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-	=Chapter 19: An Introduction to the Cardiovascular System=	+	*started here on 01/11/10.
-	*75 trillion cells in the human body.	+
-	==Blood has several important functions and unique physical characteristics==	+
-	*There are 5 main functions of blood:	+
-	**The Transportation of Dissolved Gases, Nutrients, Hormones, and Metabolic Wastes.	+
-	**The Regulation of the pH and Ion Composition of Interstitial Fluids (via diffusions of over concentrated entities from or to the blood).	+
-	**The Restriction of Fluid Losses at Injury Sites (via enzymes and other substances that respond to breaks in the vessel walls).	+
-	**Defense against Toxins and Pathogens (via delivery of white blood cells and antibodies).	+
-	**Body temperature stabilization (via dispersion of excess heat or the conservation of heat).	+
-	*Plasma is the fluid matrix in which cells are suspended.	+
-	*The protein content of plasma makes it slightly more dense than water.	+
-	*'''Formed elements''' include RBCs (erythrocytes), WBCs (leukocytes), and platelets.	+	*Essay tests!
-	*There are five types of leukocytes, each with a specific function: neutrophils, eosinophils, basophils, lymphocytes, monocytes.	+	*More articles.
-	*Platelets are membrane-bound cell fragments with enzymes and "other substances" for clotting.	+	*In general, what is presented in class is what is important.
-	*Hematopoiesis = hemopoiesis = production of formed elements.	+	*She'll be doing 90% of the lecturing.
-	*Myeloid and lymphoid stem cells generate the formed elements.	+	*There is a snow day.
-	*'''Whole blood''' is the combination of plasma and formed elements.	+	*There are four equally weighted exams. "Final" is not cumulative.
-	*Blood from any location in the body has three characteristics:	+	*The last exam will be of normal exam length.
-	**a temperature of around 38C (100.4F),	+
-	**a viscosity 5-times that of water (because of proteins, formed elements, and water molecules all sticking together),	+
-	**a pH of about 7.35 to 7.45.	+
-	*An adult male has between 5 and 6 liters of blood (5.3-6.4 quarts); women usually have between 4 and 5 liters (difference is due to body size, not physiological).	+
-	**Dividing one's mass (kg) by 7 yields a rough estimate of liters of blood.	+
-	===Clinical note===	+	*stopped here on 01/11/10.
-	*A venipuncture is usually used to obtain blood because:	+	*started here on 01/13/10.
-	**superficial veins are usually easy to find,	+
-	**the walls of a vein (compared to an equally sized artery) are thinner and therefore easier to puncture,	+
-	**the blood pressure is lower in veins and therefore the puncture wound will seal more readily.	+
-	*Arterial punctures can be useful for measuring the efficiency of gas exchange at the lungs.	+
		+	=Blood=
		+	==Extracellular fluids==
		+	*Includes blood plasma, lymph, and interstitial fluid.
		+	*Lungs are a good model of interstitial fluid because the whole organ is bathed in a fluid that is critical for function but is outside of all the cells.
-	==Plasma, the fluid portion of blood, contains significant quantities of plasma proteins==	+	===Extra versus intra cellular fluids===
		+	*Protein levels are different.
		+	*Difference is maintained by plasma membrane.
		+	*Sodium is high outside the cells, potassium is high inside.
		+	*Na+ and K+ are the molecules and gradients used to move things quickly across the membrane to equilibriate.
-	===The composition of plasma===	+	===Extracellular fluid===
-	*Plasma makes up 46-63% of the volume of whole blood.	+	*Blood, lymph, and interstitial fluid are all similar in electrolytes.
-	*Plasma is 92% water.	+	*They are not similar in the amount of blood cells, proteins, and lipids.
-	*Most of the ECF of the body is plasma and water.	+	*But the difference is less than between extra and intra- cellular.
-	*Plasma and ECF are pretty similar in composition.	+
-	*Water, ions, and small solutes can flow freely between plasma and ECF at the capillaries.	+
-	*Generally, in capillaries, more liquid and solutes are transferred from the blood to the ECF than ''vice versa''.  This is possible because the lymphatic system is draining ECF from tissue, thus decreasing the amount of ECF that needs to be drained (as the cells are generating more ECF).	+
-	*The big differences between plasma and ECF are the concentrations of oxygen / carbon dioxide and the concentrations of dissolved proteins (because plasma proteins cannot diffuse across the capillary walls).	+
-	===Plasma Proteins===	+	===Functions of blood===
-	*The proteins that are found in the plasma are generally large, globular proteins and therefore cannot escape the circulatory system.	+	*Transport, regulation of heat, ph, and fluid balance, and defense.
-	*The three major proteins are albumins, globulins, and fibrinogen; these make up 99% of the plasma proteins.	+
-	*Other proteins include enzymes, hormones, and prohormones.	+
-	====Albumins====	+	====Transport====
-	*Albumins make up 60% of the plasma proteins.	+	*Moves nutrients (sugars, aas, fatty acids, electrolytes, and water), gasses (O2 and CO2), wastes (urea, uric acid, water, CO2), and hormones.
-	*They are important for generating osmotic pressure.	+	*Blood can move things that are not very soluble in water.
-	*They transport fatty acids, thyroid hormones, some steroid hormones, and some other substances.	+
-	====Globulins====	+	====Regulation====
-	*Globulins make up 35% of plasma proteins.	+	*Heat: talked about it last semester.
-	*Globulins include antibodies and transport globulins.	+	*pH:
-	*Antibodies = immunoglobulins = attack foreign proteins and pathogens.	+	**metabolism produces pH changes but the blood has buffers to deal with this.
-	*Transport globulins transport things with low water solubility and things that might otherwise be filtered out by the kidneys.	+	**blood carries acids and bases to organs of excretion.
-	**Hormone binding proteins, like thyroid-binding globulin or transcortin (ACTH), provide a reserve of hormones.	+	**blood pH is slightly alkaline: 7.35-7.45.
-	**Metalloproteins, like transferrin, transport metals.	+	*Fluid balance:
-	**Apolipproteins carry triglycerides and other lipids.	+	**Osmotic balance is normal even though osmolytes are different.
-	**Steroid-binding proteins, like testosterone-binding globulin (TeBG), bind and transport steroid hormones.	+
-	====Fibrinogen====	+	====Defense====
-	*Fibrinogen makes up 4% of the plasma protein.	+	*Phagocytic cells:
-	*In a blood sample, one must make sure that the fibrinogen doesn't get converted to fibrin, otherwise '''serum''' is generated and the sample is no longer a proper '''plasma''' sample.	+	**Part of the innate immune system.
		+	**Ingest microorganisms.
		+	*Antibody producing cells (B cells), T cells,
		+	**Part of the specific immune system.
		+	*Chemicals to regulate blood flow and clotting.
-	====Other plasma proteins====	+	===Blood as a tissue===
-	*Other proteins found in the plasma include insulin, prolactin (PRL), TSH, FSH, LH, etc.	+	*Blood is more viscous than water.
		+	**This is because of proteins, cells, etc.
		+	**Changing levels or proteins or cells can change viscocity which can mean it takes more work to pump it around.
		+	**If the blood volume is elevated, the resulting elevated blood pressure can damage vessels and strain the heart.
-	====Clinical note====	+	==Blood - detail of components==
-	*Plasma expanders can be used to increase blood volume temporarily.	+	*After centrifugation, you get the plasma (55%), the buffy coat (the leukocytes, platelets), and the erythrocytes (RBCs, 45%).
-	*These are better than donated plasma because donations can be contaminated with viruses or bacteria.	+	*The erythrocyte fraction is called the hematocrit.
-	*Saline can be used but it is quickly absorbed into the ECF.	+	*Anemia is not making enough RBCs and therefore presents with too low hematocrit.
-	*So one can add solutes that cannot diffuse into the ECF, such as lactate in ''Ringer's solution''.	+	*Polycythemia is making too many RBCs and therefore presents with too high hematocrit.
-	*Even lactate, however, is eventually absorbed by the liver, skeletal muscles, and other tissues.	+	*Hydration can also change hematocrit, too.
-	*So we could add saline with lots of albumin in it (because it cannot be absorbed through capillaries).	+	*Plasma and serum are different.  Serum results from allowing RBCs to clot and then spinning out.  If you put in anticoagulant in, then spin, you generate plasma.  So the difference is that plasma has clotting factors and serum doesn't.
-	*The best, however, is large carbohydrate molecules in saline.  Over time, these will eventually be phagocytized by phagocytes.	+	**Edta chelates Ca++ such that blood cannot clot.
-	*Note that these only increase blood volume, they do not increase oxygen levels.	+	*95% of plasma proteins are albumins and globulins.
		+	*Fibrinogen makes up 4% of the plasma protein levels.
-	====Origins of the plasma proteins====	+	===Plasma proteins===
-	*The liver generates more than 90% of the plasma proteins, including all the albumins, all the fibrinogen, most globulins, and some prohormones.	+	*Albumin:
-	**Therefore, liver problems can lead to blood problems.	+	**Made by the liver.
-	*Lymphocytes generate plasma cells which generate antibodies.	+	**Most abundant protein in plasma.
		+	**Transports lipid-soluble components.
		+	**Add an osmotic force to the plasma.
		+	***Inside and outside of cells must be osmotically balanced and proteins can help with this.  So the albumins are blancing all the protein (like Hb) in blood cells.
		+	*Globulins:
		+	**alpha (HDL and others), beta (transferring, LDLs, VLDLs), and gamma (antibodies) globulins are called that because that's the way they came off the chromatography.  So alphas are heaviest (carrying the heaviest stuff), then beta, then gammas are the lightest.
		+	**One globulin of interest is transferrin.  It carries Fe around in the body.  It keeps Fe from wandering around and messing stuff up.  Transferrin allows the liver to store Fe.  Transferrin is a beta globulin.
		+	**The gamma globulin fraction of blood serum will have the antibodies needed after a snake bite.
		+	**Inside and outside of cells must be osmotically balanced and proteins can help with this.  So the globulins are blancing all the protein (like Hb) in blood cells.
-	==Red blood cells, formed by erythropoiesis, contain hemoglobin that can be recycled==	+	===Plasma protein function===
-	*RBCs are the most abundant cell in blood.	+	*Carriers as we've mentioned.
-	*They have hemoglobin which is a red pigment that binds oxygen.	+	*Act as buffers because they have lots of positive and negative side chains (amphoteric).
		+	*They are part of the clotting cascade.
		+	*They contribute from the osmotic pressure.  We call the choloital osmotic pressure to speak specifically of the effect of proteins on osmotic balance.
		+	*Proteins can be broken down into amino acids for energy (starvation).
-	===Abundance of RBCs===	+	==Osmotic pressure - tonicity==
-	*A single drop of blood has 260 million RBCs.	+	*Isotonic means it has the same osmotic pressure of the plasma.  Isotonic saline (0.85% NaCl) can be used to increase blood volume.
-	*There are approximately 25 trillion RBCs in the whole body.	+	*Hypertonic means that the tonicity of the plasma is higher than normal.  This can be because you have too much protein or because you have too little water.  This means water will move out of the cells.
-	*Hematocrit is the percentage of the whole blood volume made up of formed elements (which is 99.9% RBCs).	+	*Hypotonic means the tonicity of the plasma is lower than normal. This could occur because of liver disease (albumin can't be made). This decreases the choloital osmotic pressure. This causes adema because the cells will take up water to balance osmotic pressure.
-	*Adult males have hematocrit of about 46% while females are about 42%; this is primarily because the androgens found in men stimulate RBCs generation.	+
-	*Hematocrit is measured via centrifugal separation of plasma, WBCs / platelets, and RBCs.	+
-	*Because RBCS outnumber all other formed elements so easily, hematocrit is often reported as the ''volume of packed red cells'' (VPRC) or the ''packed cell volume'' (PCV).	+
-	*Hematorcit levels can vary from dehydration, EPO stimulation, or other factors.	+
-	*An abnormal hematocrit level is usually not evidence enough for diagnosis, but is an indicator that more specific tests are needed.	+
-	===Structure of RBCs===	+	==Formed elements==
-	*RBCs are highly specialized and this is reflected in their shape: a biconcave disc with a thin central region and a thicker outer marigin.	+	*We call them formed elements because most of them are not cells.
-	*The shape of a RBC is important for three reasons:	+	*Platelets nor RBCs are cells; RBCs have no nuclei and platelets are just chunks of cells.
-	**increased surface-area-to-volume-ratio for fast, efficient exchange of oxygen from intracellular proteins to tissue (through capillaries),	+	*We don't have to memorize the intermediate states of the cells (myelocytes, band cells, etc.).
-	**ability to form ''rouleaux'' (stacks of RBCs) that can flow easily through capillaries that are only slightly wider than a RBC,	+	*''Blast'' means not fully differentiated.
-	**ability to flex in order to fit through capillaries as narrow as 4 micrometers (half the normal diameter of a RBC).	+	*HSCs are committed to the hematopoietic line.
-	*RBCs have few organelles (and no nucleus in mammals) and no mitochondria and therefore have low energy demands.	+	*Factors that stimulate HSC development:
-	*The energy they do need, they generate via glycolysis of glucose absorbed from blood plasma.	+	**EPO -> RBCs
-	*RBCs cannot generate proteins.	+	**Thromopoietin -> platelets
		+	**Colony stimulating factor -> WBCs
		+	**Cytokines -> WBCs
		+	***Released by WBCs themselves and macrophages.
		+	*You can stimulate how long it takes to generate a cell but only by a day or two.
		+	*RBCs live for only a couple of weeks.
		+	*WBCs (particularly those for memory of immune pathogens) can live for years.
		+	===Erythrocytes===
		+	*Fully mature has no nucleus or organelles.
		+	*It is a biconcaved disc for increased surface area to volume ratio and flexibility.
		+	**Shape is held together by spectrin.
		+	*We can make about 2 million RBCs / second!  That's 230 billion / day.
		+	*You can make RBCs in the spleen and liver, but this is only under extreme conditions.
		+	*RBCs die after 4 months because they have no nucleus so they cannot repair themselves.
		+	*They are broken down by macrophages in the spleen, liver, and marrow.
		+	*Hemocytoblasts -> myeloid stem cells -> proerythroblast -> bone marrow -> erythroblasts (basophilic, polychromatophilic, normoblast) -> start generating lots of Hb and turning red -> loss of nucleus -> reticulocyte (still has some small organelle) -> enter circulation -> finish up making Hb -> mature red blood cell.
		+	====Stuff required for erythropoiesis====
		+	*2/3 of the body's iron is in RBCs.
		+	*We don't want to waste Fe, so we use ferritin and transferrin to store (in the liver) and transfer iron.
		+	Why is iron required?
		+	*It is required for the heme group because it is in the center.
		+	*B12 is required so you can make erythrocyte maturation factor and thus mature your RBCs.
		+	*Pyridoxine and folic acid are required for DNA synthesis since we're making lots of protein.
-	===Hemoglobin===	+	====Hormonal control of RBC production====
-	*RBCs lose any organelles not directly involved in transport of oxygen.	+	*EPO
-	*Hemoglobin (Hb) makes up 95% of intracellular protein in RBCs.	+	**Causes HSCs to go down RBC lineage.
		+	**Increases speed of differentiation.
		+	**Comes from kidney in response to hypoxia.
		+	*The stimulus is low blood oxygen, not necessarily low numbers of RBCs. So it could be:
		+	**reduced numbers of RBCs which means there is less oxygen getting carried around,
		+	**reduced O2 in the RBCs because of high altitude,
		+	***This is altitude sickness: can't catch breath, heart is going a mile a minute, etc.  Gets better because you make more RBCs.
		+	**increased tissue demand for O2 because of aerobic exercise.
		+	*EPO extends the life of patients on dialysis.  It used to be that they handed out EPO to the most needy dialysis patients.  Now that we have a recombinant form, it is abused by athletes.
		+	**EPO increases RBCs which increases O2 carrying ability which leads to increased stamina.  However, more RBCs also means increased viscocity and makes the heart work harder.
-	====Hemoglobin structure====	+	===Article about EPO abuse===
-	*Hemoglobin is made up of four globular chains, 2 alpha and 2 beta units.	+	*There have been 18 deaths among top cyclists because of EPO.
-	*Each chain, like myoglobin, contains a heme unit which is a non-protein pigment complex.	+	*Hard to measure abuse of EPO because it is natural.
-	*Each heme group contains an iron ion which can easily bind and unbind oxygen.	+	*So we try to measure the hematocrit (RBCs) but this can be counter-acted with saline injection.  Well, this leads to increased volume and harder work on the heart and death.
-	*When the iron binds oxygen, the hemoglobin unit is called oxyhemoglobin. These are bright red.	+	*Doping is when you take some blood out before the event and inject them back in before the event.
-	*When the iron does not bind oxygen, it is called deoxyhemoglobin. These appear dark red or burgundy.	+	*So, this is hard to catch, too, because hematocrit levels are quite variable based on temperature, work load, etc.
		+	*So this article suggests that we measure via transferrin receptor : ferritin ratio.
		+	*Transferring receptors are released by the RBC precursor cells so Transferrin receptor will go up whenever RBC production is up.
		+	*Ferritin gets broken down if it doesn't have Fe bound.
		+	*If you're making lots of RBCs, then Ferritin isn't storing any Fe, so it is going down.
		+	*So the ratio will be very sensitive because one factor (transferrin receptor) is going up and the other (ferritin) is going down.
		+	===More regulation of RBC production===
		+	*Intrinsic factor is required for absorbing B12 from diet.
		+	*B12 + IF bind to form erythrocyte maturation factor which is required for the last steps of RBC maturation.
		+	*If you don't have this, your RBCs will not be carrying as much oxygen and a form of anemia will occur.
		+	*stopped here on 01/13/10.
		+	*started here on 01/20/10.
-	*Infants have fetal hemoglobin (hemoglobin F) which binds oxygen more readily. In this way a fetus can "steal" oxygen from it's mother's blood stream.	+	====Hemoglobin====
-	*Hemoglobin F can be stimulated via hydroxyurea or butyrate and thus treat blood disorders like sickle cell anemia or thalassemia.	+	*Carries both oxygen and CO2.
		+	*Hb is made up of four peptide chains and four heme groups.
		+	*Heme is iron surrounded by a porferin ring.
		+	*It takes many enzymes to make the porferin ring.
		+	*Oxygen binds to heme group, CO2 binds to peptide chains.
		+	*Color of heme complex changes upon binding: bright red when oxygenated.
		+	*CO2 is more readily bound by Hb after it has lost it's oxygens.
		+	*The four chains are two sets of pairs: alpha and beta chains.
		+	*There are other versions of Hb, however, which are made of different chains.
		+	**96% is 2 alpha, 2 beta.
		+	**2% is the '''A2 form''': 2 alphas, 2 deltas.
		+	**2% is fetal Hb: 2 alpha, 2 gammas.
		+	***Fetal hemoglobin has a higher affinity for O2 such that the fetus can steal oxygen from the maternal blood supply.
		+	***Change over from fetal form to adult form 6 months after birth.
		+	Are the different chains different genes or splice variants.
		+	*Different genes.
-	====Hemoglobin function====	+	====Sickle Cell Disease====
-	*Each RBC has about 280 million hemoglobin (Hb) proteins which each have four heme groups. Thus, each RBC can carry over 1 billion molecules of oxygen.	+	*Named for the shape of the RBC.
-	*98.5% of all oxygen in the blood is carried by Hb molecules inside RBCs.	+	*Especially common in the malaria belt of Africa.
-	*When plasma oxygen levels drop, Hb releases oxygen.	+	*Phenotype is different shape, less flexibility, increased lysing of cells.
-	*When plasma CO2 levels increase, the alpha and beta chains of Hb bind CO2.  This state is called carbaminohemoglobin.	+	*Note that only the homozygous case shows the diseased phenotype because most of the beta chains will be good.
-	*These binding balances shift in the capillaries and the lungs where gas exchange is occurring.	+	*The shape blocks easy flow of blood causing hypoxia and tissue death and swelling.
-	*If hematocrit levels decrease or Hb levels within RBCs decrease, not enough oxygen will be delivered to tissues--anemia.	+	*A sickle cell crisis has pain, swelling, tissue death.
-	*Anemia can present with weakness, lethargy, and confusion as muscles, organs, and the brain are all being deprived of oxygen.	+	*Most populous form is a 2 aa change in the beta chain.
		+	**Wikipedia says glutamate to valine via one nucleotide change.
		+	*Sickle cell death was one of the first where protein mutation was characterized.  Done with individual aa sequencing.
		+	*Even though we know all this, we have no cure.
		+	*So why does this (potentially pre-maturation lethal mutation) survive in population?
		+	**The hypothesis is that it must convey some advantage to the individual.
		+	**And it does: patients who are carriers and diseased for the beta chain gene are resistant to malaria.
		+	***This occurs because the cells leak potassium which is lethal to the malaria parasite.
		+	***It could also be because malaria spends some of its time inside the cells and the ion concentration difference is harmful to the parasite.
-	===RBC formation and turnover===	+	====Biophysics of sickle cell hydroxyurea therapy====
-	*RBCs must be constantly replaced because they incur much damage in their 700 mile, 120 day lifespan.	+	*When beta chain polymerizes, you get less oxygen carrying ability and cell shape change.
-	*Phagocytes engulf and digest aging RBCs upon detection of damage.	+	*The beta chains will polymerize when they are deoxygenated.
-	*1% of all RBCs are produced and digested each day--that's a rate of 3 million new RBCs each second!	+	*The delay time for polymerization (after deoxygenation) should be longer than the transit time from capillaries (where oxygen is removed) to the lungs (where oxygen is added again).
		+	*The math shows us that if we can increase the delay time even just a little, we can make a big difference.
		+	*Hydroxyurea increases fetal Hb which increases the delay time.
		+	*Hydroxyurea can only be used in adults, because it can affect bone marrow and stem cells and might mess up growth in children.
		+	*Old paper, but there doesn't seem to be new therapies.
		+	*Arginine butyrate also increases Fb.
-	====Clinical note: Abnormal hemoglobin====	+	===RBC turnover===
-	*Two well known genetic disorders resulting in abnormal hemoglobin are thalassemia and sickle cell anemia.	+	*RBCs have a 100-120 day lifespan.
-	*Thalassemia results from the too-slow production of alpha or beta units, the subsequent low concentration of Hb in RBCs, fragile and short-lived RBCs, and thus problems with development and growth of systems throughout the body.	+	*Macrophages in spleen and liver recycle the RBCs.
-	*Patients with thalassemia may require transfusions to increase components of the blood.	+	*When broken down:
-	*Sickle cell anemia is due to a mutation in the beta chain of Hb.	+	**Aas are put into blood stream.
		+	**Iron from heme group is bound to transferrin in the blood stream.
		+	***Note that transferrin is pretty abundant.
		+	***Extra iron (that is, transferrin-bound iron) is stored in the liver.
		+	**Porferin ring is a pigment that gets broken down into biliveriden, then bilirubin, then leaves the macrophage and enters the liver via albumin, then excreted in the bile, then gets secreted (mostly in the feces, some in the urine).
		+	***Bilirubin is toxic if free in the blood.
		+	***Don't need to know all the forms, good enough to know that it gets convereted and to know the track it follows.
		+	===Jaundice===
		+	*This is a build up of bilirubin that the liver can't handle and thus it ends up in the blood stream and other tissues of the body (eyes, skin, mucus membranes).
		+	*Recall that bilirubin is toxic, mainly to the nervous system.
		+	Is it a neutortransmitter that overloads the system.
		+	*Can be caused by liver disease (one cannot process or cannot transport bilirubin) or by excessive tissue damage (because bunches of RBCs are getting turned over).
		+	*Jaundice can also be seen in newborns with a not-quite-mature liver.
		+	**Happens even in full-term babies.
		+	**It is easy to treat when the liver will mature, you just treat the bilirubin: put them under UV light because bilirubin is broken down by UV light.
		+	===Anemia===
		+	*There are lots of causes.
		+	*Can be a decrease in RBCs or a decrease in amount of oxygen carrying capacity.
		+	*Regardless of cause, symptoms include weakness, shortness of breath, chills, chronic mental and physical fatigue.
		+	**All of this due to lack of making ATP because of lack of oxygen.
-	====Hemoglobin conservation and recycling====	+	====Causes of anemia====
-	*The heme prosthetic group in hemoglobin and myoglobin is heme B.	+
-	*Macrophages and phagocytes of the liver, spleen, and bone marrow engulf deteriorating RBCs, generally (90% of the time) before they rupture (hemolyze).	+
-	*If a RBC does hemolyze, the hemoglobin will deteriorate into alpha and beta chains and be excreted via the kidneys which may lead to hemoglobinuria (red or brown urine).	+
-	*Upon damage to the kidney or vessels along the urinary tract, hematuria may occur such that fully intact RBCs are found in the urine.	+
-	*The amino-acid chains of hemoglobin are broken down into aas in the macrophages and either used in the macrophage or secreted into the blood for use by other cells.	+
-	*The heme units first have there iron molecules removed making them biliverdin (a greenish color that shows up in bruises) which gets converted into bilirubin (an orangish color) and dropped into the bloodstream where albumin transports it to the liver for excretion via bile.	+
-	**Macrophage + heme -> biliverbin -> bilirubin -> bloodstream + albumin -> liver -> bile -> out.	+
-	*If the liver cannot absorb or secrete bilirubin, the bilirubin will build up in peripheral tissues like the sclera and the skin and cause '''jaundice'''.	+
-	*Bilirubin are converted into urobilinogens and stercobilinogens by bacteria in the large intestine.  Upon exposure to oxygen, these turn into urobilins and stercobilins which give urine and feces their yellow-brown, brown color.	+
		+	=====Insufficient RBCs=====
		+	*Hemorrhagic anemia
		+	**Perhaps because of loss of blood.
		+	**Remember that this can be a slow, consistent loss, like an ulcer.
		+	*Hemolytic anemia
		+	**Body makes RBCs but they are lysing.
		+	***There may be a defect in the membrane causing them to not last as long (say 40 days) such that your body has to be making more RBCs all the time.
		+	**Incorrect infusion
		+	***This can cause lysis of lots of RBCs.
		+	**Parasitic infections.
-	====Iron====	+	*Aplastic anemia:
-	*Iron released into the blood at the liver upon destruction of heme units is bound to transferrin for transport in the blood.	+	**Most likely in cancer patients.
-	*Bone marrow tissue absorbs iron so that it can generate new Hb.	+	**Something about work environment.
-	*Ferritin and hemosiderin are used by the liver and spleen to store excess amounts of iron.	+	***I think has to do with the fact that exposure to toxins can cause aplastic anemia and the workplace is often a place of toxin exposure.
-	*This recycling program of iron from digested heme to generation of new heme is quite efficient--only 1-2 mg of iron is needed in the diet while 26 mg are used each day to produce heme units.  That is, only 1-2mg of the 26mg of iron generated from the breakdown of RBCs is lost each day.	+
-	*So, too little iron (which will decrease RBC production) or too much iron (which will increase irons stores in the liver and cardiac tissue) can cause health issues.	+
-	===RBC production===	+	=====Decreases in hemoglobin production=====
-	*Embryonic blood cells appear in the blood stream at week three.	+	*Iron-deficiency anemia
-	*For the first 8 weeks, the yolk sac is where most blood is generated.	+	**Could be from poor diet with too little iron.
-	*As other organs develop, some ESCs move into the liver, spleen, thymus, and bone marrow where they will differentiate into stem cells that generate blood cells.	+	**Inadequate absorption of iron
-	*The liver and spleen are the primary organs producing blood cells for months 2-5 of development-until the bone can mature into having marrow.	+	***There are diseases that can cause this.  Some are hereditary.
-	*In adults, RBCs are generated ''only'' in the marrow.	+	**Loss of irons stores
-	*RBCs are generated in red bone marrow (myeloid tissue).	+	***Liver disease can cause this problem.
-	*Red bone marrow is found in the vertebrae, scapulas, ribs, sternum, pelvis, skull, and the proximal limb bones.	+	**Deficiencies in iron metabolism
-	*Yellow marrow can be converted to red marrow upon extreme and sustained duress.	+	***This is very rare, might occur in iron transport proteins.
-	====Stages in RBC maturation====	+	*Pernicious anemia
-	*Hemocytoblasts can generate myeloid stem cells and lymphoid stem cells which will generate red / white blood cells and lymphocytes, respectively.	+	**This is a deficiency of vitamin B12.
-	*Hemocytoblasts -> myeloid stem cells -> proerythroblasts -> erythroblasts (basophilic -> polychromatophilic -> normoblast) -> reticulocyte -> mature RBC.	+	**If you don't have enough B12, then even if you have ''intrinsic factor'' you can't develop Erythrocyte Maturation Factor which is crucial for RBC maturation.
-	*Erythroblasts actively generate hemoglobin and are named based on their size, the amount of hemoglobin presnet, and the appearance of their nucleus.	+	**This would lead to immature RBC formation.
-	*As a reticulocyte, the cell enters circulation with 80% of its Hb generated.  Though the nucleus is gone, the RNA needed to generate the last 20% of Hb is still present.  After 24 hours in circulation, all the Hb has been generated and the RNA is gone.	+
		+	=====Abnormal hemoglobin=====
		+	*Thalassemia
		+	**Common in the Greek population.
		+	**This is a broken synthesis of the globin chains.
		+	**Alpha and beta versions are deficient in synthesis of their respective chains.
		+	*Sickle cell
		+	**Talked about it.
-	====Regulation of Erythropoiesis====	+	===Polycythemia===
-	*Generating RBCs requires that the bone marrow get enough nutrients, including vitamin B12.	+	*Too many RBCs.
-	*B12 comes from dairy and meat in our diet.	+	*Not as rare as you'd think.
-	*The stomach generates something called ''intrinsic factor'' which is required for absorbing B12.	+	*Polycythemia vera (true) comes from a tumor that generates lots of RBCs.
-	*When there isn't enough B12, pernicious anemia occurs.	+	**This is rare.
-	**This can occur because of too little B12 in the diet, too little production of ''intrinsic factor'' or because of an abnormality with B12/''intrinsic factor'' absorption.	+	**Usually due to tumors.
-	*Generating RBCs can be stimulated with erythropoietin, thyroxine, androgens, and growth hormone.  Note, however that estrogen does not stimulate RBC generation.	+	*Secondary polycythemia occurs when a consequence of a disorder is the increased production of RBCs.
-	*EPO is a glycoprotein.	+	**High altitudes:
-	*EPO is produced by the liver and kidneys.	+	***Don't have adverse effects like use of EPO.
-	*EPO is generated when peripheral tissues or the kidneys experience hypoxia which might occur because of:	+	**Emphysema:
-	**anemia,	+	***This and pulmonary fibrosis change the structure of the lung such that there is inefficient gas exchange causing low oxygen at the kidney and a continuous signal to make more RBCs.
-	**decreased blood flow to kidneys,	+	**Pulmonary fibrosis:
-	**decreased oxygen concentration in respired air (high altitude),	+
-	**damaged lung respiratory surfaces.	+
-	*EPO acts on the stem cells found in bone marrow to increase generation of erythroblasts from their progenitors and to increase erythroblast division.	+
-	*EPO also acts to increase RBC maturation rates, sometimes up to 30 fold faster!	+
-	*EPO arc: Kidney / peripheral tissues suffer hypoxia -> Liver / kidney produce / release EPO -> blood stream -> bone marrow -> myeloid cells generate more erythroblasts, erythroblasts divide more rapidly to make more RBCs, and RBCs mature faster.	+
-	*Using EPO to increase RBC counts in for athletes is dangerous because it puts a strain on the heart because of increased viscocity.	+
-	*'''Blood doping''' is when you take blood out of an athlete, sequester the RBCs, and then reinfuse them at a later date to increase RBC counts.	+
-	*Blood tests can be used to quickly, cheaply, and unobtrusively assess a patient's health in several ways.	+
		+	===Porphyrins===
		+	*A mutation in one of the many enzymes that make this complex ring molecule can cause disease.
		+	*This class of diseases are called porphuria.
		+	*Vincent van Gogh had this disease as did the royal family of Transylvania.
		+	*There are many different forms of the disease depending on the different parts of the pathway affected.
		+	*Some of these forms of disease seem to get worse at puberty.
		+	Why does that make sense?
		+	*Symptoms:
		+	**Skin lesions caused by sunlight.
		+	**Gum degeneration.
		+	**Rampant hair growth (hands and face, especially).
		+	**Aggravated by alcohol and certain chemicals in garlic.
		+	**Crankiness.
		+	**Inability to clear toxins (or something like that?).
		+	*Treatment:
		+	**Infusion of red blood cells from healthy donors.
		+	===Restoration of blood volume===
		+	*Isotonic fluids can restore blood volume.
		+	*For whole blood cells and packed RBCs, you have to do blood typing.
		+	*Anemia needs packed RBCs.
-	==The ABO blood types and Rh system are based on antigen-antibody response==	+	===Blood typing===
-	*Antigens are usually proteins but some other organic molecules can also act as antigens.	+	*Measures antigens on RBCs.
-	*Our own cells have surface antigens that mark them as native, also called agglutinogens.	+	*If you mismatch, the host cells will kill the infused cells and agglutination will occur (a clumping of the cells that are being attacked).
-	*RBCs have over 50 surface antigens, but three of particular importance are A, B, and Rh (D).	+	**This will hit the kidney first, causing kidney failure, and resulting in sepsis.
-	*These 50 antigens are integrated glycoproteins or integrated glycolipids.	+
-	*Type O: 46%, type A: 40%, type B: 10%, type AB: 4% (of US population).	+
-	*Blood plasma contains '''agglutinins''' which attack cells with foreign antigens and cause a clumping together called agglutination.	+
-	*Rh antigens are a little different in that an Rh negative patient will not have anti-Rh antigens until they have been ''sensitized'' or exposed (perhaps via pregnancy with an Rh positive child or via a transfusion).	+
		+	====ABO Antigens====
		+	*Two types: A and B.
		+	*Can have one, both, or neither.
		+	*Type AB has no antibodies so they can receive any type of blood.
		+	*Type O has A and B antibodies so they can only get O blood.
		+	*The antibodies from the donor will react onto the host blood cells, but there are not enough to be a problem.
		+	====Rh factor====
		+	*Rh because it was first described in a rhesus monkey.
		+	*Most people are Rh positive.
		+	*If you are Rh negative, you don't have the antibodies inherently, you must be sensitized to them.
		+	*So you can tolerate the first interaction, but then the person will develop antibodies.
		+	Why wouldn't you develop an immune response to the B antigen?
		+	*If you're type A and you get AB blood, you don't develop the B antibodies because you already have them.  So in this ABO case, the reaction would look like the Rh reaction upon second exposure.
-	===Cross-reactions in transfusions===	+	=====Rh in pregnancy=====
-	*When blood antigen types are not matched for a transfusion, the agglutinogens will cause the foreign cells to clump together which can block blood vessels in lethal areas like the lungs, heart, brain, or kidneys.	+	*This also manifests itself as a problem when the mother is Rh- and the fetus is Rh+.
-	*Remember that the reaction of the recipient's plasma antigens against the donor's RBCs is more important when considering cross-reaction potential because the donation will only include a very small amount of the donor's plasma such that it's attack on the recipient's RBCs will probably not generate harmful clumping.	+	**This isn't a problem in the first pregnancy because Rh factors don't cross the placental membrane.
-	**This means that one must consider most carefully the antigens on the donor's RBCs.	+	**During delivery, however, the membranes rupture and the two circulation systems can mix such that the Rh+ fetal cells enter the mother's system and she develops antibodies.
-	*One unit of blood is 500ml, of which 275ml is plasma (because the plasma content has been reduced).	+	**Still not a problem.
		+	**However, once she has a second child that is Rh+, the antibodies can cross the membrane such that '''hemolytic disease of newborns''' occurs.
		+	**This can only be treated with an in-utero blood transfusion.
		+	**So why don't ABO cause this problem?  Because they are too large and cannot cross the membrane.
		+	*Rh factor and pregnancy:
		+	**You can treat a first-time mother with RhoGam which binds the antigen (Rh factor) and blocks the mother's immune reaction.
		+	Does RhoGam prevent issues with Rh+ baby once the mother has been sensitized?
		+	**If you don't do this, and the mother develops antibodies, the fetus of a second pregnancy will require transfusions before birth and after birth (because the mom's antibodies are still floating around).
-	===Testing for transfusion compatibility===	+	===White blood cells===
-	*Before a transfusion, a compatibility test is run which identifies the antigens of the donor and then shows the results of a cross-match test.	+	*They combat foreign substances in the body.
-	*To identify antigens on a donor's RBCs, two separate drops are exposed to anti-A and anti-B antigens; if there is a reaction with both, the blood type is AB, if only with one, then A or B, respectively.	+	*They engulf stuff, chemically detoxify stuff, produce antibodies, and release chemical messengers.
-	*Rh is also noted (but the book didn't say how this test was run, which is interesting because one wouldn't necessarily have anti-Rh antigens even if they are Rh-).	+	*This provides an '''integrated defense system'''.
-	*When time permits, we try to match all 50 antigens because, though it is rare, it is possible to have a reaction to one of the other 48 antigens.	+	*WBCs must be able to leave the bloodsteam, called diapedesis.
-	*Blood typing is inherited and therefore is used in paternity testing and in crime scene detection.	+	*Lymphocytes can leave circulation and come back in; the other 5 types only cross out of the blood, then die.
-	**Testing for the other 48 antigens increases accuracy and DNA testing can generate 100% surety.	+	*Leukocytes are attracted (to cross the vessel wall) by inflammatory responses, chemical attractants, tissue damage, or chemicals released by infected tissue.
		+	*Lymphoid line leads to basophils, eosinophils, and neutrophils.
		+	*One can characterize leukocytes by nucleus shape and whether or not they have granules (spottiness in the microscope).
		+	*We want to be able to identify these cells because a differential count can give us clinically relevant clues to what is going on.
		+	====Granulocytes====
		+	*Neutrophils: stain lilac with acidic and basic dyes.
		+	*Eosinophils: stain with acidic dyes.
		+	*Basophils: stain with basic dyes.
		+	====Agranulocytes====
		+	*Monocytes:
		+	**Turn into macrophages.
		+	**Are not terminally differentiated.
		+	*Lymphocytes:
-	==The various types of white blood cells contribute to the body's defenses==	+	*White blood cells are only a small part of the blood volume.
-	*In a microliter of blood, there are about 5-10K WBCs and 4-6M RBCs.	+	*Neutrophils are most abundant among WBCs in the blood, then lymphocytes, monocytes, and eosinophils.
-	*Most WBCs are found in the connective tissue or organs of the lymphoid system.	+
-	*WBCs can be identified in a smear with a Wright stain or a Giemsa stain.	+
-	**Granular leukocytes = granulocytes: neutrophils, eosinophils, and basophils with large secretion vesicles and lysosomes.	+
-	**Agranular leukocytes = agranulocytes: monocytes and lymphocytes with much smaller vesicles and lysosomes.	+
-	===WBC circulation and movement===	+	*we'll finish Blood next time and all the readings.
-	*WBCs mostly reside and migrate through the loose and dense connective tissue.	+
-	*The only travel through the blood stream to get where they are going.	+
-	*As they are traveling through the blood stream, they can exit upon detection of a signal indicating damage.	+
-	*There are four characteristics of circulating WBCs:	+
-	**they can exit the blood stream by adhering to the endothelial wall (margination) and squeezing through the endothelial wall (emigration or diapedesis),	+
-	**they are capable of amoeboid movement through the ECM which requires ATP and Ca++,	+
-	**they are sensitive to specific chemical stimuli which act as positive chemotaxants toward damaged tissue and other activated WBCs,	+
-	**Neutrophils, eosinophils, and monocytes are capable of phagocytizing cells and materials.	+
-	*Macrophages are just monocytes that have moved out of the blood stream and are actively phagocytic.	+
-	===Types of WBCs===	+	*stopped here on 01/20/10.
-	*Neutrophils, eosinophils, basophils, and monocytes are nonspecific defenses.	+	*started here on 01/25/10.
-	*Lymphocytes are specific defenses.	+
-	====Neutrophils====	+	*we probably won't finish blood today.
-	*Neutrophils are also called polymorphonuclear leukocytes because the nucleus has several dense lobes.	+
-	*Neutrophils got their name from having a neutral coat that is hard to stain because it doesn't attract acidic or basic dyes.	+
-	*Neuts make up 50-70% of circulating WBCs.	+
-	*They have lysosomes with enzymes and bactericidal compounds.	+
-	*Neuts are very fast and active and generally the first on the scene of an injury.	+
-	*They can attack and digest bacteria and other cells that have been marked with complement proteins.	+
-	*Once a neutrophils has engulfed a cell, it turns on it's metabolism to high (called ''respiratory burst'') in order to generate superoxides and hydrogen perioxides (called ''defensins'').	+
-	*The phagocytized cell is then fused with the lysosomes (degranulation) and the enzymes destroy the cell by eating away it's membrane.	+
-	*Neutrophils also release leukotrienes to attrack other leukocytes to the site of attack.	+
-	*Neutrophils release prostaglandins in order to make the capillaries near the injury more permeable and therefore contribute to local inflammation.	+
-	*Neutrophils live about 10 hours in the blood stream, perhaps only 30 minutes if they are attacking a bad guy.	+
-	*Pus is a mixture of dead neutrophils, cellular debris, and other waste products.	+
		+	*Neuts are most abundant, then lymphocytes.
		+	*The others are important, too, though.
		+	=====Neutrophils=====
		+	*AKA polymorphonuclear leukocytes.
		+	*They usually last about 10 hours in the circulation unless activated to fight an infection.
		+	*They are the most active early-on in an infection because they can be recruited very quickly.
		+	*They are phagocytes so they can get rid of bad guys pretty quickly via hydrolytic-proteolytic enzymes.
		+	*They can also ingest particlate matter.
		+	*They release prostaglandins and leukotrienes which are inflammatory and chemoattractants for other leukocytes.
		+	*Neuts have multiple types of granulocytes:
		+	**Those containing hydrolytic-proteolytic enzymes (to fuse to phagocytized pathogen, or to release into the tissue).
		+	***Note that if you release these granules, there will be tissue damage and you will have inflammation.
		+	**Those containing defensisns, small molecular compounds that are good at poking holes in microorganisms, thus causing it to die.
		+	**Granules with prostanoids (contains prostaglandins and leukotrienes) which do some tissue damage to cause inflammation and attract other white blood cells.  This processes generally kills neutrophils such that pus is formed by the broken bodies of neutrophils.
		+	*Neuts are the most motile of all granulocytes.
-	====Eosinophils====	+	======The tangled webs that neutrophils weave======
-	*Eosinophils stain easily with eosin, a red dye.	+	*Explores how neutrophils can contain some of their noxious chemicals.
-	*They have a bilobed nucleus and are about the same size as a neut.	+	*The paper observed that when stimulated, the neutrophils were secreting DNA (which is very sticky) and histones and proteins beyond just the prostaglandins that we knew about.
-	*They make up only 2-4% of circulating WBCs.	+	**Some of these things degrade bacterial virulence factors.
-	*These guys can engulf antibody laden bad guys but generally secrete nitric oxide and cytotoxic enzymes.	+	**The authors also suggest that the DNA and proteins may serve to contain the tissue damage and the microbes.
-	*They are particularly good at attacking multicellular parasites.	+	*They determined that the neutrophils died when secreting all these things, but not through lysis.
-	*Eosinophils multiply rapidly when parasitic infection occurs or allergens are detected.	+	*Questions that remain:
-	*Eosinophils help reduce inflammation by neuts and mast cells at a site of infection, keeping it from spreading to adjacent tissue.	+	**What are the signals that make neuts do this?
		+	**Why don't all neuts do this?
		+	**How do we control this process?
-	====Basophils====	+	=====Eosinophils=====
-	*Basophils can be stained with basic dyes.	+	*Make up only 2-4% WBCs.  That is, in a normal, healthy person with no infections, etc.
-	*Basophils are smaller than neuts and eosinophils.	+	*Eosinophils are less motile than neuts, but they definitely migrate.
-	*They make up only 1% of the WBC population.	+	*The cells phagocytize proteins thus detoxifying them.
-	*Basophils release their granules into the interstitial fluid.	+	*Eosinophils have oxydases, peroxidases, and phosphatases in their granules so they can release it and destroy pathogens (find out which ones).
-	*The granules include:	+	*These cells follow chemotactants generated by an antigen-antibody interaction.
-	**histamine to dilate blood vessels,	+	*Eosinophils can also be signaled to move by mast cells / basophils (same thing for our concerns).
-	**heparin to prevent blood clotting,	+	*Eosinophils are increased upon allergic reactions and autoimmune diseases because of signals from basophils and antigen-antibody interactions.
-	**chemicals to reduce inflammation started by mast cells,	+	*Eosinophils inactivate inflammtory chemicals like histamine (because histamine is a protein).
-	**chemicals to attract eosinophils,	+	*Kill things too large for phagocytosis.
-	**chemicals to attract more basophils.	+
-	====Monocytes====	+	=====Basophils=====
-	*Monocytes are the largest WBCs.	+	*Basophils are localized whereas mast cells are systemic.
-	*Monocytes make up 2-8 percent of the WBC population.	+	*Only 1% of the WBCs.
-	*Monocytes have a kidney or oval shaped nucleus.	+	*Found more outside the bloodstream than inside (especially connective tissue).
-	*Monocytes are only in the bloodstream long enough to get to their tissue, then they become a resident macrophage.	+	*Their granules contain heparin and histamine (an anticoagulant and a vasodilator, respectively).
-	*Macrophages phagocytize aggressively.	+	**These two factors increase blood flow to an infected area, increase eosinophil and neutrophil recruitment, and increase capillary permeability.
-	*While phagocytizing, macrophages release factors that attract neutrophils, monocytes, other phagocytic cells, and fibrocytes.	+	**This is all good when there is an infection.
-	*The fibrocytes will build scar tissue.	+
	====Lymphocytes====		====Lymphocytes====
-	*Lymphocytes are 20-30% of the circulating WBC population.	+	*Second most abundant after neuts, 20-30%.
-	*Lymphocytes have a large round nucleus with only a little cytoplasm surrounding it.	+	*Found mostly in the lymphoid peripheral tissue, not in blood.
-	*Lymphocytes are circulating through the blood, peripheral tissue, and lymphatic system constantly.	+	*There are three types:
-	*The circulating fraction is only a very small portion of all lymphocytes, however.	+	**T cells: responsible for cell mediated immunity (directly killing other cells that are infected).
-	*There are three functional classes of lymphocytes, none of which can be distinguished with a microscope:	+	**B cells: antibody mediated immunity (target cells for degradation).
-	**T cells either attack foreign cells themselves or coordinate a response involving the other lymphocyte classes. T cells are responsible for ''cell-mediated immunity''.	+	**Natural Killer cells: recognize global types of antigens.
-	**B cells are responsible for the ''humoral immunity'' (fluid immunity) of the body because as mature cells (plasma cells) they generate antibodies that attack antigens on foreign cells throughout the body.	+	*B and T cells are very specific; NK cells are not that specific.
-	**Natural killer cells are responsible for immune surveillance--the detection and destruction of abnormal tissue cells like those of cancers.	+
-	*Note that T cells must migrate to their target but B cells generate antibodies which can act anywhere in the body.	+	====Monocytes====
		+	*Only live for a few days in blood stream, then move into tissue.
		+	*Originate in bone marrow.
		+	*Only fully differentiate upon moving into tissue, into macrophages.
		+	*Macrophages are phagocytic.
		+	*Macrophages release chemical signals to recruit more phagocytic cells.
		+	*There are several types of macrophages:
		+	**Fixed: reside in a particular tissue.  Then we name them like "alveolar macrophage" or "liver macrophage".
		+	**Wandering: move throughout tissues.
		+	*Macrophages are also antigen presenting cells, so they ride the fence between the innate and the adaptive immune systems.
		+	*Microglia are the macrophages of the brain.
		+
		+	====Differential WBC count====
		+	*This is about determining the relative amount of each type of WBC.
		+	*You take the buffy coat and count them.
		+	*These can support an hypothesis like those below but cannot prove any of them.
		+	*High neuts: bacterial infection or severe tissue destruction.
		+	**Upon tissue damage, platelets will recruit neutrophils.
		+	*High eosinophils: allergic reactions, parasitic infector or autoimmune disease.
		+	**Because mast cells and basophils recruit eosinophils.
		+	*High basophils: allergic reaction.
		+	*High lymphocytes: viral infection (because viruses are ''inside'' the cell, so a T cell must detect the presented antigen).
		+	*High monocytes: viral or fungal infection.
		+
		+	===Thrombocytes===
		+	*Platelets!
		+	*Come from the myeloid lineage.
		+	*The progenitor cell grows and turns into the huge megakaryocyte.
		+	*Platelets come from parts of the megakaryocyte breaking off.
		+	*Platelets have no nucleus but are surrounded by membranes.
		+	*Platelet granules contain serotonin, Ca++, enyzmes, ADP, PDGF.
		+	*Platelets aggregate and adhere to sites of vascular damage.
		+	*Platelets are key for sealing a broken vessel by aggregation.
		+	*This is the first line of defense for a broken vessel.
		+	*Megakaryocytes are generated through lots of mitosis but no cell division.
		+	*A single megakaryocyte will give off thousands of platelets.
		+	*Thrombopoietin enhances formation of mkcyte and increases formation of platelets.
		+
		+	====The root of platelet formation====
		+	*It is not just a random breaking apart of the mgcyte.
		+	*There were two theories going into this research:
		+	**Cytoplasmic fragmentation: mgcytes have cell membranes running through them that divide the cytoplasm into the platelets and then it enters the blood stream and fragments.
		+	**Proplatelet elaboration: Mgcytes sit outside the blood vessels and extend processes into the blood vessels and the sheer force of the blood stream pulls off chunks of platelets.
		+	*To distinguish between these theories, the authors:
		+	**engineered the mice to have fluorescent mgcytes,
		+	**opened marrow cavity of the brain,
		+	**use microscopy to watch the mgcyte, (this is hard to do in live animals)
		+	*Visualization of the process shows that the megakaryocyte has a membrane bound inner sac and that the mgcyte's membrane runs through the endothelial wall of the vessel such that the sheer force of the blood stream pulls off chunks of the process.
		+	*The speed of blood flow may determine how fast platelets are being broken off.
-	===The differential count and changes in WBC profiles===	+	===Leukopoiesis===
-	*We can often tell what is going on in a body by looking at the numbers of each type of WBC in a sample.	+	*Generation of WBCs.
-	*''penia'' means ''too little''.	+	*We don't need to know all the factors for each line of WBCs.
-	*''osis'' can mean ''too many''.	+	*Colony-stimulating factors is the name giving to all the leukopoiesis factors.
-	*So ''leukopenia'' means there is a low count of leukocytes (WBCs) and ''lukocytosis'' means there may be too many.	+	*All WBCs differentiate to some degree in bone marrow.
-	*''Leukemia'' refers to having boatloads of WBCs.	+	*Lymphocytes fully differentiate in lymphoid tissue.
		+	*Some of the CSFs are generated by macrophages and T-lyphocytes.
		+	*Phagocytic cells have a shorter lifespan than others.
		+	*Lymphocytes can live for years.
		+	*Leukocytes are broken down by the liver, spleen, and lymph nodes.
		+	*Increased WBCs generally means there is an infection.
		+	*Leukemia is a proliferation of immature WBCs.
		+	**Leukemias are named for their type of precursor from which they came.
		+	===WBC physiology===
		+	*In order to fight stuff, WBCs have to get out of the circulation.
		+	*There are different chemotactants for each type of WBC.
		+	*Many of these signals come from other WBCs, infected tissue, or from an infectious agent itself.
		+	*Most cells move out through the capillaries, not the main blood vessels and thus there are few cells that must be crossed by the WBCs.
		+	*Blood and cells in it are moving rapidly, however, so we must first slow down the exiting cells.
		+	*So first, it starts getting a little sticky such that it rolls.
		+	*On the endothelial cells there are selectins which interact with integrins on the exiting WBCs.  These interact to slow cells down and make them sticky.  There must be something controlling this, however, otherwise all WBCs would leave all the time!
		+	*Only lymphocytes can leave and reenter the blood stream; all others can only leave and die.
		+	====Adhesion Molecules: the path to a new understanding of acute inflammation====
		+	*This article says that chemical crosstalk is bidirectional between the exiting WBCs and the endothelial cells being crossed.
		+	*Here's the process:
		+	**A macrophage in tissue recognizes a foreign body and is giving off soluble mediators (like histamines, interleukins, etc.).
		+	**The endothelial cells and WBCs are affected by the soluble mediators.
		+	**Selectins on the PMN move out onto the tips of the cell membrane because of the signal and then the selectins start interacting with glycoproteins on the endothelial cells.  After some protein synthesis, even more selectins will be expressed.
		+	**Finally, the WBC binds and doesn't move.
		+	**Now the endothelial cell will present more immunoglobulins (fueled by inflammatory signals) such that there is tight binding.  Here, integrins bind tightly to the endothelial cells after being activated by the signals from macrophages.
		+	**Diapedesis is mediated by e-cadherin interactions.
		+	**Then the WBC flattens and spreads out.
		+	**Then WBC migrates through the tight junction.
		+	**Then WBC resumes rounder shape and performs its function.
		+	She said both have selectins.  Which cell has integrins?
		+	*Only leukocytes.
-	===WBC Production===	+	===Clinical considerations===
-	*This image is pretty much all we need to know.	+
		+	====Bone marrow transplantation====
		+	*Useful because it is enriched in stem cells.
		+	*Useful for treatment for radiation poisoning or chemotherapeutic drug poisoning.
		+	*It can also be useful for gene therapy because we can fix a problem and put it in the person and know that the change will be propagated.
		+	*We need to be careful to avoid immune reaction.
		+	**This is about HLA typing, not ABO or Rh typing.
		+	**The only identical HLA types are identical twins.
		+	**This is a typing for the antigens on host cells that might cause an immune response.  So we type as closely as possible so an immune response won't be too strong.
		+	*There is a possibility of graft versus host disease.
		+	**This is the opposite of normal transplant rejection considerations.
		+	**With bone marrow, it is possible for the donor marrow to mount an attack against the host, and that is not good.
		+	**And therefore we need to remove T-cells (lymphocytes).
		+	====Alternatives to bone marrow transplantation====
		+	*As the ability to do transplants becomes more possible, it is more needed so we don't have enough bone marrow.
		+	*But really all we need is the stem cells from bone marrow.
-	====Regulation of WBC production====	+	=====Clinical promise - ethical quandry=====
-	*The thymus secretes hormones that stimulate the production of T cells, that is, until the thymus stops working in youth.	+	*Normally UCB (umbilical cord blood) is discarded after birth.
-	*Therefore, in adults, it is the exposure to antigens that increases production of B and T cells.	+	*UCB SCs must be typed but not as strictly because it hasn't developed all of its HLA types.
-	*The non-lymphocyte WBCs are stimulated by colony-stimulating factors (CSFs).	+	**So it isn't as likely to cause an immune rejection.
-	*There are four CSFs:	+	*It has been estimated that if we just collected all the blood from every delivery, we would have all the stem cells we could need.
-	**M-CSf stimulates production of monocytes.	+	*Questions:
-	**G-CSF stimulates the production of the granulocytes (neutrophils, eosinophils, and basophils).	+	**What's the best way to collect it and store it?
-	**GM-CSF stimulates the production of monocytes and granulocytes.	+	**How long can it be stored?
-	**Multi-CSF accelerates the production of granulocytes, monocytes, platelets, and even RBCs.	+	**What testing is necessary to protect the recipient?
-	*Communcation between lymphocytes and other WBCs occurs via chemicals like the CSFs and EPO.	+	***Which tests do you do and how many do you do?
-	*Some of these communicatory chemicals are approved for clinical use: like G-CSF = filgrastim = neupogen which is given to chemotherapy patients to increase their neutrophil count.	+	**Which patient should receive the treatment until sufficient stores can be built up?
		+	***It is especially useful for treating childhood diseases and adults take more.
		+	*Issues keeping us from collecting all UCB:
		+	**Do you need to get consent from donor parents?
		+	**Should testing for genetic disease be performed?
		+	**Should the parents be informed of the results of the genetic disease?
		+	***What if the disease is terminal?
		+	***What if the disease was chronic (diabetes) and could be affect insurance coverage?
		+	*Other ethical issues:
		+	**Who should regulate the use of the material?
		+	**Should companies be allowed to approach parents before delivery to store cord blood when it is not known how long the blood can be stored?
		+	***Remember that we don't know how long it will last so maybe by 30 it's no good anymore.
		+	*$125 annual storage fee, $1700 for kit and processing, $150 shipping service, and probably multiple thousands of dollars for a Dr. to use the kit to collect the blood.
-	==Platelets, disc-shaped structures formed from megakaryocytes, function in the clotting process==	+	=====Ubilical cord blood transplantation and banking=====
-	*Platelets are called thrombocytes in nonmammals because they are still nucleated cells.	+	*An update on the previous paper.
-	*Platelets are important for clotting, along with plasma proteins and the cells and tissues of the blood vessels themselves.	+	*Stem cells are not totally free of immune response; it is still required that you do some typing.
-	*About 1/3 of our platelets are found in the spleen and other vascular organs while 2/3 are circulating.	+	*Partial response is acceptable and reduces the risk of GVHD.
-	*Platelets circulate for about 10 days before being phagocytized.	+	*Banking can occur for at least 5 years.  But beyond that we don't know.
-	*Thrombocytopenia (too few platelets) generally occurs because of bleeding along the digestive tract, withing the skin, or within the CNS (and thus platelets are lost faster than made).	+	*The issue of testing:
-	*Thrombocytosis (too many platelets) often results from accelerated production in response to infection, inflammation, or cancer.	+	**What is done now: HLA tissue typing, a few infectious agents.
		+	**No rules, no consensus, only a best practice guide by the FDA.
		+	*UCB stem cells seem to proliferate more slowly than native HSCs.
		+	*It is hard to use UCB in adults because it takes so many for a good transplantation.  This often requires multiple sources (donors) and the two fight and one overcomes the other.  However, this isn't a big problem, really.
		+	**During the first month, there is double chimerism: three different genetic materials--the host and the two recipients.
		+	*HLA matching isn't as important because
		+	*Many times these cells don't proliferate as well.
-	===Platelet function===	+	==Hemostasis==
-	*Platelets:	+
-	**release enzymes and other factors at the appropriate time to help initiate clotting,	+
-	**form a clump of platelets to plug up injuries of vessels,	+
-	**contract (via actin / myosin) to make the size of the clotted area / damaged area smaller.	+
-	===Platelet production===	+	*stopped here on 01/25/10.
-	*The generation of platelets (thrombocytopoiesis) is facilitated by megakaryocytes in the bone marrow.	+	*started here on 01/27/10.
-	*Megakaryocytes are large, have a large nucleus, and generate lots of proteins, enzymes, and membrane.	+
-	*Then segments of the megakaryocyte's cell body are slowly sheered off by the blood stream and thus are made platelets.	+
-	*Thrombocytopoiesis can be stimulated via:	+
-	**thrombopoietin (TBO, AKA: thrombocyte-stimulating factor) which is a peptide hormone produced in the kidneys,	+
-	**IL-6,	+
-	**multi-CSF.	+
-	==Hemostasis involves vascular spasm, platelet plug formation, and blood coagulation==	+	*Hemostasis is how the blood contributes to homeostasis.
-	*Hemostasis literally means blood halting; it is about stopping blood loss.	+	*What happens when a blood vessel is broken>?
-	*There are three, intermixed stages: vascular, platelet, coagulation.	+	*Four steps:
-	===The vascular phase===	+	===Local vasoconstriction===
-	*The vascular phase begins first and includes the contraction of the smooth muscle that surrounds the injured vessel. This cans slow or even stop blood loss.	+	*This is called the vascular phase.
-	*Three changes in the endothelium occur during the vascular phase:	+	*Vasculature is constricted immediately.
-	**Endothelial cells contract and expose the underlying basal lamina to the blood stream,	+	*This slows blood loss.
-	**Endothelial cells release chemical factors including ADP, tissue factor, prostacyclin, and endothelins.	+	*Collagen is exposed and cells release ADP, tissue factor, and prostacyclin.
-	***Endothelins stimulate smooth muscle contraction and the division of endothelial cells, smooth muscle cells, and fibrocytes.	+	*Collagen, ADP, and tissue factor and prostacyclin are important for the next two steps.
-	**The endothelial cells of the vessel wall become sticky and thus stick together to help seal the break.  This also helps faciliate the beginning of the platelet phase.	+
-	===The platelet phase===	+	===Formation of a platelet plug===
-	*The platelet phase begins upon ''platelet adhesion'' to the sticky endothelial cells as well as collagen fibers.	+	*Prostaglandins, thromboxanes, and prostacyclins form the prostanoids.
-	*Then the platelets aggregate to form a plug which can sometimes top blood loss if the injury is small.	+	**Prostacyclins inhibit clot formation.
-	*Platelet aggregation occurs within 15 seconds of an injury.	+	**Prostaglandins encourage clot formation.
-	*Platelets become activated as they arrive at the site of injury and thus they release:	+	*Platelets, upon being exposed to collagen, degranulate.
-	**ADP to stimulate platelet aggregation and secretion,	+	*Platelets release:
-	**Thromboxane A2 and serotonin to stimulate vascular spasms,	+	**ADP: stimulates platelet aggregation and secretion,
-	**Proteins that play a role in clotting (called ''clotting factors''),	+	**Thromboxin A2 and serotonin: stimulate vascular spasms,
-	**PDGF, a peptide hormone that promotes vessel repair, and	+	**clotting factors: proteins that play a role in clotting,
-	**calcium ions which help will aggregation and clotting.	+	**PDGF: helps epithelial repair,
-	*Because each platelet is releasing all this stuff, there is positive feedback such that this process occurs rapidly.	+	**Ca++: helps with the next couple of steps.
-	*Therefore, plug formation must be limited to the site of injury by several factors:	+	*This forms a plug by the stickifying of the membranes such that they stick to each other and to the broken cells of the endothelium and the collagen.
-	**Prostacyclin is released by endothelial cells,	+	*So how do we limit it to the site of injury?
-	**Inhibitory compounds are released by WBCs,	+	**Through the release of prostacyclin (PGI2) by endothelial cells which reduces platelet coaggulation.
-	**Plasma enzymes break down ADP (which is stimulating aggregation) near the plug,	+	**Through the breakdown of ADP by emzymes in the blood.
-	**Compounds (like serotonin) which, at high levels, block formation of more plug material, and	+	**Through high levels of serotonin which block the action of ADP to further clot formation.
-	**The formation of a blood clot isolates the plug (and therefore all the factors encouraging more plug formation) from the general circulation.	+	**Through the fact that prostaglandins (which are encouraging clot formation) have very short half-lives in the blood so they don't react throughout the body because they are degraded before they can travel very far.
		+	*So how does aspirin affect the clotting cascade?
		+	**A low dose of aspirin inhibits prostaglandins and thus decreases the platelet degranulation reaction and thus decreases plug formation.
		+	**A high dose of aspirin can affect the formation of PGI2 and thus decrease PGI2's ability to reduce platelet coaggulation.
-	===The coagulation phase===	+	===Clotting cascade===
-	*The coagulation phase takes about 30 seconds to sit in while the vascular and platelet take 0-15 seconds.	+	*This cascade involves tens to a hundred of proteins.
-	*In the coagulation phase, the blood clot is formed over the platelet plug via a complex series of steps that convert fibrinogen (a soluble protein circulating in the blood) into a mesh of fibrin in which other blood cells and such get stuck to form a filled mesh that will become something like a scab and effectively stop blood loss.	+	*We'll only study a simple model.
-	*	+	*An enzyme called thrombin converts fibrinogen (soluble in the blood) to fibrin (which is an insoluble fibrous plasma protein).
		+	*Fibrin then forms a mesh that traps RBCs and some plasma to form a clot.
		+	*The roman numerals describe the order in which they were discovered.
		+	*Other names have poorer logic like "christmas factor".
		+	*There are three stages:
		+	**Formation of prothrombinase,
		+	***prothrombinase cuts thrombinogen to thrombin.
		+	**Conversion of prothrombin to thrombin
		+	**Conversion of fibrinogen to fibrin
		+	*Intrinsic means all the factors are in the blood, extrinsic means some come from outside the blood.
		+	*There are two ways to activate factor X: intrinsic (slower) and extrinsic (faster).
		+	*We don't need to memorize the pathways.
		+	*Note, however, that Ca++ and vitamin K are absolutely necessary for both intrinsic and extrinsic cascading.
		+	*What activates intrinsic versus extrinsic.
		+	**Extrinsic would be factor III from a damaged endothelial cell whereas intrinsic would be factor XII from the blood.
		+	*Common pathway:
		+	**Requires Ca++ (can use Ca++ chelators to stop clotting).
		+	**Requires vitamin K because it is required for production of many of the proteins in this cascade, like prothrombin, and factors 7, 9 and 10.
		+	***Vitamin K comes from bacteria in the large intestine and is absorbed as a fat soluble vitamin.
		+	**Factor X generates prothrombinase which then cuts prothrombin into thrombin which then cuts fibrinogen to fibrin.
		+	===Clot retraction and dissolution===
		+	*As time goes on, the clot draws together to close wound and open a vessel.
		+	*Clot retraction is initiated by thrombosthenin, a platelet factor.
		+	*Now we need to get rid of the clot.
		+	*Fibrin is broken down by plasmin, a proteolytic enzyme.
		+	*Plasminogen must be activated into plasmin.
		+	*TPA = tissue plasminogen activator is formed by the endothelial cells and cleaves plasminogen into plasmin such that fibrin is degraded.
		+	*Staphlokinase and streptokinase are from bacteria and used clinically to activate TPA.
		+	*We use SK and SP to break apart clots in stroke and MI patients.
		+	====Clot busters====
		+	*SK and SP break up clots, that's their clinical use.
		+	*However, since, SK and SP are exogenous, they can produce an immune response.
		+	**They are cheaper (than tPA), however, because we can get them from growing up bacteria.
		+	*Note that SK will break down free fibrin which increases your chance of bleeding.
		+	*Read article on our own.
-	====Clotting factors====	+	===Anticoagulants===
-	*Clotting factors = procoagulants.	+	*There are two types: physiological (endogenous) and therapeutic (clinically administered).
-	*Clotting factors are generally proenzymes that go through a cascade of activation in order to start the clotting process.	+	*Physiological:
-	*Ca++ is also a clotting factor.	+	**PGI2 is a prostenoid that inhibits platelet adhesion (a prostacyclin).
-	*Clotting occurs through two pathways; the intrinsic pathway begins in the bloodstream while the extrinsic pathway begins outside the bloodstream, in the vessel wall.	+	**Antithromboplastin inactivates TF3 which is part of the clotting cascade. Antitrhomboplastin normally serves to balance.
-	*Both pathways activate the common pathway (see diagram above) via ''factor x''.	+	**Factor C is similar to antithromboplastin in that it blocks TFV and TFVIII.
		+	**Heparin which is released by basophils / mast cells, inactivates thrombin, thromboplastin, and prothrombin.
		+	*Therapeutics:
		+	**Heparin is great because it is natural and it can be reversed.
		+	**Calcium chelators cannot be used ''in vivo'' because it will kill them because no calcium means no neurotransmission or muscular function.
		+	**Warfarin or dicumarol inhibit synthesis of prothrombin by limiting use of vitamin K in the liver.
		+	***Warfarin won't completely inhibit clotting, so it can be titrated.
		+	===Disorders of hemostasis===
		+	====Thrombocytopenia====
		+	*Low numbers of platelets.
		+	*Can come from
		+	**decreased production in bone marrow from radiation or cytotoxic chemicals.
		+	**sequestration of platelets by the spleen
		+	***congestive splenomegaly: what is this?
		+	**destruction of platelets by autoimmune disease
		+	***idiopathic thrombocytopenic purpura: when the immune system breaks down the body's immune system.
		+	*Symptoms: easy bruising because capillaries break all the time and usually platelets are the simple fix.  There may also be bleeding in the joints because vessels there take a large beating.
-	====The extrinsic pathway====	+	====Disseminated intravascular coagulation====
-	*The extrinsic pathway starts by the release of factor III by damaged endothelial cells.	+	*This is blood clot formation in the capillaries.
-	*Factor III interacts with Ca++ and other factors to activate factor x.	+	*Usually happens in respnose to bacterial infection that damages endothelial cells.  This exposes collagen and starts the platelet clotting process.
		+	*When amniotic fluid leaks into the blood stream, it can cause init of platelet and clotting cascade.
		+	*Rarely, cancers can start this cascade.
-	====The intrinsic pathway====	+	====Hemophilia====
-	*The intrinsic pathway begins when proenzymes in the blood are activated by exposure to collagen (or a glass test tube).	+	*Hemophilia A: deficiency in factor 8
-	*Then several platelet factors and clotting factors interact before they activate factor x.	+	**85%
		+	*B: deficiency in factor IX
		+	*C: deficiency in factor XI.
		+	*A and B are x-linked so males are infected and women are carriers.
		+	*C is not x linked and is not as severe.
		+	*Symptoms include uncontrolled bleeding, subcutaneous bleeding, vessel damage in the joints, and actual damage in the joints.
-	====The common pathway====	+	====Deficiencies in clotting factors====
-	*The common pathway begins when factor x is activated which forms prothrombinase.	+	*Afibrogenemia:
-	*Prothrombinase converts prothrombin into thrombin which converts fibrinogen into fibrin.	+	**there is a hereditary form but is usually from liver disease.
		+	**if the liver isn't working, then not all the clotting proteins can be made, like fibrinogen.
-	====Interactions among the pathways====	+	*Hypoprothrombinemia
-	*The extrinsic pathway is shorter and faster and produces a quick, but small amount of thrombin.	+	**liver disease can cause this, as can vitamin K deficiency because K is required for generation of prothrombin.
-	*Clotting occurs in a matter of minutes.	+	**Hemorrahgic disease of newborns:
		+	***Because newborns don't have the normal bacteria in the gut that generates vitamin k or if their liver isn't fully formed, they may not be able to generate the proteins well enough.
		+	**Therefore it makes sense that if you are taking lots of antibiotics you may become vit k deficiency.
-	====Feedback control of blood clotting====	+	=====Thromboembolytic disorders====
-	*The common pathway speeds up both the extrinsic and intrinsic pathways via positive feedback, thus making clotting a very fast process.	+	*Thrombus:
-	*Because there is such positive feedback, there are also many factors that inhibit clot formation:	+	**A clot in an unbroken blood vessel which may occlude the whole vessel.
-	**Anticoagulants found in blood plasma,	+	**If the vessel is a coronary vessel, it generates a heart attack.
-	**Heparin, released by basophils and mast cells,	+	**We're most worried about clots in heart, lungs and brain.
-	**Thrombomodulin released by endothelial cells which activates '''protein C''' which deactivates fibrin strands,	+
-	**Prostacyclin from the platelet phase.	+
-	*Many clinical conditions require close regulation and manipulation of clotting and anticlotting factors.	+
-	====Calcium ions, vitamin K, and blood clotting====	+	*Embolus:
-	*Ca++ is required in all three pathways: intrinsic, extrinsic, and common.	+	**When a clot moves to a bad location.
-	*Vitamin K is required for the liver to generate many of the clotting factor proteins found in plasma.	+
-	*Therefore anything that messes up Ca++ or vitamin K levels can affect the patient's ability to clot.	+
-	*Vitamin K is fat soluble.	+
-	*Half our vitamin K needs are absorbed in the diet and half is generated by bacteria in the gut.	+
-	====Clot retraction====	+	*Aspirin use:
-	*Within about 30 to 60 minutes, a clot has formed and platelets are pulling together to reduce residual bleeding and to make it easier for fibrocytes, smooth muscle cells, and endothelial cells to complete their repairs.	+	**Low doses inhibits thromboxane A2 formation and therefore platelet and aggregation.
		+	**In high doses, will affect PGI2 and will have the opposite affect because it inhibits the inhibitor.
-	===Fibrinolysis===	+	*moved on to the [[Lymphatic / Immune notes]] on 01/27/10.
-	*The fibrin network can be broken down via plasminogen.	+
-	*For everything to work properly, blood has to keep flowing.  RBCs make about 2 circuits per minute.	+

---

Revision as of 02:40, 14 February 2010

• started here on 01/11/10.

• Essay tests!
• More articles.
• In general, what is presented in class is what is important.
• She'll be doing 90% of the lecturing.
• There is a snow day.
• There are four equally weighted exams. "Final" is not cumulative.
• The last exam will be of normal exam length.

• stopped here on 01/11/10.
• started here on 01/13/10.

Contents 1 Blood 1.1 Extracellular fluids 1.1.1 Extra versus intra cellular fluids 1.1.2 Extracellular fluid 1.1.3 Functions of blood 1.1.3.1 Transport 1.1.3.2 Regulation 1.1.3.3 Defense 1.1.4 Blood as a tissue 1.2 Blood - detail of components 1.2.1 Plasma proteins 1.2.2 Plasma protein function 1.3 Osmotic pressure - tonicity 1.4 Formed elements 1.4.1 Erythrocytes 1.4.1.1 Stuff required for erythropoiesis 1.4.1.2 Hormonal control of RBC production 1.4.2 Article about EPO abuse 1.4.3 More regulation of RBC production 1.4.3.1 Hemoglobin 1.4.3.2 Sickle Cell Disease 1.4.3.3 Biophysics of sickle cell hydroxyurea therapy 1.4.4 RBC turnover 1.4.5 Jaundice 1.4.6 Anemia 1.4.6.1 Causes of anemia 1.4.6.1.1 Insufficient RBCs 1.4.6.1.2 Decreases in hemoglobin production 1.4.6.1.3 Abnormal hemoglobin 1.4.7 Polycythemia 1.4.8 Porphyrins 1.4.9 Restoration of blood volume 1.4.10 Blood typing 1.4.10.1 ABO Antigens 1.4.10.2 Rh factor 1.4.10.2.1 Rh in pregnancy 1.4.11 White blood cells 1.4.11.1 Granulocytes 1.4.11.2 Agranulocytes 1.4.11.2.1 Neutrophils 1.4.11.2.1.1 The tangled webs that neutrophils weave 1.4.11.2.2 Eosinophils 1.4.11.2.3 Basophils 1.4.11.3 Lymphocytes 1.4.11.4 Monocytes 1.4.11.5 Differential WBC count 1.4.12 Thrombocytes 1.4.12.1 The root of platelet formation 1.4.13 Leukopoiesis 1.4.14 WBC physiology 1.4.14.1 Adhesion Molecules: the path to a new understanding of acute inflammation 1.4.15 Clinical considerations 1.4.15.1 Bone marrow transplantation 1.4.15.2 Alternatives to bone marrow transplantation 1.4.15.2.1 Clinical promise - ethical quandry 1.4.15.2.2 Ubilical cord blood transplantation and banking 1.5 Hemostasis 1.5.1 Local vasoconstriction 1.5.2 Formation of a platelet plug 1.5.3 Clotting cascade 1.5.4 Clot retraction and dissolution 1.5.4.1 Clot busters 1.5.5 Anticoagulants 1.5.6 Disorders of hemostasis 1.5.6.1 Thrombocytopenia 1.5.6.2 Disseminated intravascular coagulation 1.5.6.3 Hemophilia 1.5.6.4 Deficiencies in clotting factors 1.5.6.5 =Thromboembolytic disorders

Blood

Extracellular fluids

• Includes blood plasma, lymph, and interstitial fluid.
• Lungs are a good model of interstitial fluid because the whole organ is bathed in a fluid that is critical for function but is outside of all the cells.

Extra versus intra cellular fluids

• Protein levels are different.
• Difference is maintained by plasma membrane.
• Sodium is high outside the cells, potassium is high inside.
• Na+ and K+ are the molecules and gradients used to move things quickly across the membrane to equilibriate.

Extracellular fluid

• Blood, lymph, and interstitial fluid are all similar in electrolytes.
• They are not similar in the amount of blood cells, proteins, and lipids.
• But the difference is less than between extra and intra- cellular.

Functions of blood

• Transport, regulation of heat, ph, and fluid balance, and defense.

Transport

• Moves nutrients (sugars, aas, fatty acids, electrolytes, and water), gasses (O2 and CO2), wastes (urea, uric acid, water, CO2), and hormones.
• Blood can move things that are not very soluble in water.

Regulation

• Heat: talked about it last semester.
• pH:
  • metabolism produces pH changes but the blood has buffers to deal with this.
  • blood carries acids and bases to organs of excretion.
  • blood pH is slightly alkaline: 7.35-7.45.
• Fluid balance:
  • Osmotic balance is normal even though osmolytes are different.

Defense

• Phagocytic cells:
  • Part of the innate immune system.
  • Ingest microorganisms.
• Antibody producing cells (B cells), T cells,
  • Part of the specific immune system.
• Chemicals to regulate blood flow and clotting.

Blood as a tissue

• Blood is more viscous than water.
  • This is because of proteins, cells, etc.
  • Changing levels or proteins or cells can change viscocity which can mean it takes more work to pump it around.
  • If the blood volume is elevated, the resulting elevated blood pressure can damage vessels and strain the heart.

Blood - detail of components

• After centrifugation, you get the plasma (55%), the buffy coat (the leukocytes, platelets), and the erythrocytes (RBCs, 45%).
• The erythrocyte fraction is called the hematocrit.
• Anemia is not making enough RBCs and therefore presents with too low hematocrit.
• Polycythemia is making too many RBCs and therefore presents with too high hematocrit.
• Hydration can also change hematocrit, too.
• Plasma and serum are different. Serum results from allowing RBCs to clot and then spinning out. If you put in anticoagulant in, then spin, you generate plasma. So the difference is that plasma has clotting factors and serum doesn't.
  • Edta chelates Ca++ such that blood cannot clot.
• 95% of plasma proteins are albumins and globulins.
• Fibrinogen makes up 4% of the plasma protein levels.

Plasma proteins

• Albumin:
  • Made by the liver.
  • Most abundant protein in plasma.
  • Transports lipid-soluble components.
  • Add an osmotic force to the plasma.
    • Inside and outside of cells must be osmotically balanced and proteins can help with this. So the albumins are blancing all the protein (like Hb) in blood cells.
• Globulins:
  • alpha (HDL and others), beta (transferring, LDLs, VLDLs), and gamma (antibodies) globulins are called that because that's the way they came off the chromatography. So alphas are heaviest (carrying the heaviest stuff), then beta, then gammas are the lightest.
  • One globulin of interest is transferrin. It carries Fe around in the body. It keeps Fe from wandering around and messing stuff up. Transferrin allows the liver to store Fe. Transferrin is a beta globulin.
  • The gamma globulin fraction of blood serum will have the antibodies needed after a snake bite.
  • Inside and outside of cells must be osmotically balanced and proteins can help with this. So the globulins are blancing all the protein (like Hb) in blood cells.

Plasma protein function

• Carriers as we've mentioned.
• Act as buffers because they have lots of positive and negative side chains (amphoteric).
• They are part of the clotting cascade.
• They contribute from the osmotic pressure. We call the choloital osmotic pressure to speak specifically of the effect of proteins on osmotic balance.
• Proteins can be broken down into amino acids for energy (starvation).

Osmotic pressure - tonicity

• Isotonic means it has the same osmotic pressure of the plasma. Isotonic saline (0.85% NaCl) can be used to increase blood volume.
• Hypertonic means that the tonicity of the plasma is higher than normal. This can be because you have too much protein or because you have too little water. This means water will move out of the cells.
• Hypotonic means the tonicity of the plasma is lower than normal. This could occur because of liver disease (albumin can't be made). This decreases the choloital osmotic pressure. This causes adema because the cells will take up water to balance osmotic pressure.

Formed elements

• We call them formed elements because most of them are not cells.
• Platelets nor RBCs are cells; RBCs have no nuclei and platelets are just chunks of cells.
• We don't have to memorize the intermediate states of the cells (myelocytes, band cells, etc.).
• Blast means not fully differentiated.
• HSCs are committed to the hematopoietic line.
• Factors that stimulate HSC development:
  • EPO -> RBCs
  • Thromopoietin -> platelets
  • Colony stimulating factor -> WBCs
  • Cytokines -> WBCs
    • Released by WBCs themselves and macrophages.
• You can stimulate how long it takes to generate a cell but only by a day or two.
• RBCs live for only a couple of weeks.
• WBCs (particularly those for memory of immune pathogens) can live for years.

Erythrocytes

• Fully mature has no nucleus or organelles.
• It is a biconcaved disc for increased surface area to volume ratio and flexibility.
  • Shape is held together by spectrin.
• We can make about 2 million RBCs / second! That's 230 billion / day.
• You can make RBCs in the spleen and liver, but this is only under extreme conditions.
• RBCs die after 4 months because they have no nucleus so they cannot repair themselves.
• They are broken down by macrophages in the spleen, liver, and marrow.
• Hemocytoblasts -> myeloid stem cells -> proerythroblast -> bone marrow -> erythroblasts (basophilic, polychromatophilic, normoblast) -> start generating lots of Hb and turning red -> loss of nucleus -> reticulocyte (still has some small organelle) -> enter circulation -> finish up making Hb -> mature red blood cell.

Stuff required for erythropoiesis

• 2/3 of the body's iron is in RBCs.
• We don't want to waste Fe, so we use ferritin and transferrin to store (in the liver) and transfer iron.

Why is iron required?
*It is required for the heme group because it is in the center.

• B12 is required so you can make erythrocyte maturation factor and thus mature your RBCs.
• Pyridoxine and folic acid are required for DNA synthesis since we're making lots of protein.

Hormonal control of RBC production

• EPO
  • Causes HSCs to go down RBC lineage.
  • Increases speed of differentiation.
  • Comes from kidney in response to hypoxia.
• The stimulus is low blood oxygen, not necessarily low numbers of RBCs. So it could be:
  • reduced numbers of RBCs which means there is less oxygen getting carried around,
  • reduced O2 in the RBCs because of high altitude,
    • This is altitude sickness: can't catch breath, heart is going a mile a minute, etc. Gets better because you make more RBCs.
  • increased tissue demand for O2 because of aerobic exercise.
• EPO extends the life of patients on dialysis. It used to be that they handed out EPO to the most needy dialysis patients. Now that we have a recombinant form, it is abused by athletes.
  • EPO increases RBCs which increases O2 carrying ability which leads to increased stamina. However, more RBCs also means increased viscocity and makes the heart work harder.

Article about EPO abuse

• There have been 18 deaths among top cyclists because of EPO.
• Hard to measure abuse of EPO because it is natural.
• So we try to measure the hematocrit (RBCs) but this can be counter-acted with saline injection. Well, this leads to increased volume and harder work on the heart and death.
• Doping is when you take some blood out before the event and inject them back in before the event.
• So, this is hard to catch, too, because hematocrit levels are quite variable based on temperature, work load, etc.
• So this article suggests that we measure via transferrin receptor : ferritin ratio.
• Transferring receptors are released by the RBC precursor cells so Transferrin receptor will go up whenever RBC production is up.
• Ferritin gets broken down if it doesn't have Fe bound.
• If you're making lots of RBCs, then Ferritin isn't storing any Fe, so it is going down.
• So the ratio will be very sensitive because one factor (transferrin receptor) is going up and the other (ferritin) is going down.

More regulation of RBC production

• Intrinsic factor is required for absorbing B12 from diet.
• B12 + IF bind to form erythrocyte maturation factor which is required for the last steps of RBC maturation.
• If you don't have this, your RBCs will not be carrying as much oxygen and a form of anemia will occur.

• stopped here on 01/13/10.
• started here on 01/20/10.

Hemoglobin

• Carries both oxygen and CO2.
• Hb is made up of four peptide chains and four heme groups.
• Heme is iron surrounded by a porferin ring.
• It takes many enzymes to make the porferin ring.
• Oxygen binds to heme group, CO2 binds to peptide chains.
• Color of heme complex changes upon binding: bright red when oxygenated.
• CO2 is more readily bound by Hb after it has lost it's oxygens.
• The four chains are two sets of pairs: alpha and beta chains.
• There are other versions of Hb, however, which are made of different chains.
  • 96% is 2 alpha, 2 beta.
  • 2% is the A2 form: 2 alphas, 2 deltas.
  • 2% is fetal Hb: 2 alpha, 2 gammas.
    • Fetal hemoglobin has a higher affinity for O2 such that the fetus can steal oxygen from the maternal blood supply.
    • Change over from fetal form to adult form 6 months after birth.

Are the different chains different genes or splice variants.
*Different genes.

Sickle Cell Disease

• Named for the shape of the RBC.
• Especially common in the malaria belt of Africa.
• Phenotype is different shape, less flexibility, increased lysing of cells.
• Note that only the homozygous case shows the diseased phenotype because most of the beta chains will be good.
• The shape blocks easy flow of blood causing hypoxia and tissue death and swelling.
• A sickle cell crisis has pain, swelling, tissue death.
• Most populous form is a 2 aa change in the beta chain.
  • Wikipedia says glutamate to valine via one nucleotide change.
• Sickle cell death was one of the first where protein mutation was characterized. Done with individual aa sequencing.
• Even though we know all this, we have no cure.
• So why does this (potentially pre-maturation lethal mutation) survive in population?
  • The hypothesis is that it must convey some advantage to the individual.
  • And it does: patients who are carriers and diseased for the beta chain gene are resistant to malaria.
    • This occurs because the cells leak potassium which is lethal to the malaria parasite.
    • It could also be because malaria spends some of its time inside the cells and the ion concentration difference is harmful to the parasite.

Biophysics of sickle cell hydroxyurea therapy

• When beta chain polymerizes, you get less oxygen carrying ability and cell shape change.
• The beta chains will polymerize when they are deoxygenated.
• The delay time for polymerization (after deoxygenation) should be longer than the transit time from capillaries (where oxygen is removed) to the lungs (where oxygen is added again).
• The math shows us that if we can increase the delay time even just a little, we can make a big difference.
• Hydroxyurea increases fetal Hb which increases the delay time.
• Hydroxyurea can only be used in adults, because it can affect bone marrow and stem cells and might mess up growth in children.
• Old paper, but there doesn't seem to be new therapies.
• Arginine butyrate also increases Fb.

RBC turnover

• RBCs have a 100-120 day lifespan.
• Macrophages in spleen and liver recycle the RBCs.
• When broken down:
  • Aas are put into blood stream.
  • Iron from heme group is bound to transferrin in the blood stream.
    • Note that transferrin is pretty abundant.
    • Extra iron (that is, transferrin-bound iron) is stored in the liver.
  • Porferin ring is a pigment that gets broken down into biliveriden, then bilirubin, then leaves the macrophage and enters the liver via albumin, then excreted in the bile, then gets secreted (mostly in the feces, some in the urine).
    • Bilirubin is toxic if free in the blood.
    • Don't need to know all the forms, good enough to know that it gets convereted and to know the track it follows.

Jaundice

• This is a build up of bilirubin that the liver can't handle and thus it ends up in the blood stream and other tissues of the body (eyes, skin, mucus membranes).
• Recall that bilirubin is toxic, mainly to the nervous system.

Is it a neutortransmitter that overloads the system.

• Can be caused by liver disease (one cannot process or cannot transport bilirubin) or by excessive tissue damage (because bunches of RBCs are getting turned over).
• Jaundice can also be seen in newborns with a not-quite-mature liver.
  • Happens even in full-term babies.
  • It is easy to treat when the liver will mature, you just treat the bilirubin: put them under UV light because bilirubin is broken down by UV light.

Anemia

• There are lots of causes.
• Can be a decrease in RBCs or a decrease in amount of oxygen carrying capacity.
• Regardless of cause, symptoms include weakness, shortness of breath, chills, chronic mental and physical fatigue.
  • All of this due to lack of making ATP because of lack of oxygen.

Causes of anemia

Insufficient RBCs

• Hemorrhagic anemia
  • Perhaps because of loss of blood.
  • Remember that this can be a slow, consistent loss, like an ulcer.

• Hemolytic anemia
  • Body makes RBCs but they are lysing.
    • There may be a defect in the membrane causing them to not last as long (say 40 days) such that your body has to be making more RBCs all the time.
  • Incorrect infusion
    • This can cause lysis of lots of RBCs.
  • Parasitic infections.

• Aplastic anemia:
  • Most likely in cancer patients.
  • Something about work environment.
    • I think has to do with the fact that exposure to toxins can cause aplastic anemia and the workplace is often a place of toxin exposure.

Decreases in hemoglobin production

• Iron-deficiency anemia
  • Could be from poor diet with too little iron.
  • Inadequate absorption of iron
    • There are diseases that can cause this. Some are hereditary.
  • Loss of irons stores
    • Liver disease can cause this problem.
  • Deficiencies in iron metabolism
    • This is very rare, might occur in iron transport proteins.

• Pernicious anemia
  • This is a deficiency of vitamin B12.
  • If you don't have enough B12, then even if you have intrinsic factor you can't develop Erythrocyte Maturation Factor which is crucial for RBC maturation.
  • This would lead to immature RBC formation.

Abnormal hemoglobin

• Thalassemia
  • Common in the Greek population.
  • This is a broken synthesis of the globin chains.
  • Alpha and beta versions are deficient in synthesis of their respective chains.

• Sickle cell
  • Talked about it.

Polycythemia

• Too many RBCs.
• Not as rare as you'd think.
• Polycythemia vera (true) comes from a tumor that generates lots of RBCs.
  • This is rare.
  • Usually due to tumors.
• Secondary polycythemia occurs when a consequence of a disorder is the increased production of RBCs.
  • High altitudes:
    • Don't have adverse effects like use of EPO.
  • Emphysema:
    • This and pulmonary fibrosis change the structure of the lung such that there is inefficient gas exchange causing low oxygen at the kidney and a continuous signal to make more RBCs.
  • Pulmonary fibrosis:

Porphyrins

• A mutation in one of the many enzymes that make this complex ring molecule can cause disease.
• This class of diseases are called porphuria.
• Vincent van Gogh had this disease as did the royal family of Transylvania.
• There are many different forms of the disease depending on the different parts of the pathway affected.
• Some of these forms of disease seem to get worse at puberty.

Why does that make sense?

• Symptoms:
  • Skin lesions caused by sunlight.
  • Gum degeneration.
  • Rampant hair growth (hands and face, especially).
  • Aggravated by alcohol and certain chemicals in garlic.
  • Crankiness.
  • Inability to clear toxins (or something like that?).
• Treatment:
  • Infusion of red blood cells from healthy donors.

Restoration of blood volume

• Isotonic fluids can restore blood volume.
• For whole blood cells and packed RBCs, you have to do blood typing.
• Anemia needs packed RBCs.

Blood typing

• Measures antigens on RBCs.
• If you mismatch, the host cells will kill the infused cells and agglutination will occur (a clumping of the cells that are being attacked).
  • This will hit the kidney first, causing kidney failure, and resulting in sepsis.

ABO Antigens

• Two types: A and B.
• Can have one, both, or neither.
• Type AB has no antibodies so they can receive any type of blood.
• Type O has A and B antibodies so they can only get O blood.
• The antibodies from the donor will react onto the host blood cells, but there are not enough to be a problem.

Rh factor

• Rh because it was first described in a rhesus monkey.
• Most people are Rh positive.
• If you are Rh negative, you don't have the antibodies inherently, you must be sensitized to them.
• So you can tolerate the first interaction, but then the person will develop antibodies.

Why wouldn't you develop an immune response to the B antigen?
*If you're type A and you get AB blood, you don't develop the B antibodies because you already have them.  So in this ABO case, the reaction would look like the Rh reaction upon second exposure.

Rh in pregnancy

• This also manifests itself as a problem when the mother is Rh- and the fetus is Rh+.
  • This isn't a problem in the first pregnancy because Rh factors don't cross the placental membrane.
  • During delivery, however, the membranes rupture and the two circulation systems can mix such that the Rh+ fetal cells enter the mother's system and she develops antibodies.
  • Still not a problem.
  • However, once she has a second child that is Rh+, the antibodies can cross the membrane such that hemolytic disease of newborns occurs.
  • This can only be treated with an in-utero blood transfusion.
  • So why don't ABO cause this problem? Because they are too large and cannot cross the membrane.
• Rh factor and pregnancy:
  • You can treat a first-time mother with RhoGam which binds the antigen (Rh factor) and blocks the mother's immune reaction.

Does RhoGam prevent issues with Rh+ baby once the mother has been sensitized?

• • If you don't do this, and the mother develops antibodies, the fetus of a second pregnancy will require transfusions before birth and after birth (because the mom's antibodies are still floating around).

White blood cells

• They combat foreign substances in the body.
• They engulf stuff, chemically detoxify stuff, produce antibodies, and release chemical messengers.
• This provides an integrated defense system.
• WBCs must be able to leave the bloodsteam, called diapedesis.
• Lymphocytes can leave circulation and come back in; the other 5 types only cross out of the blood, then die.
• Leukocytes are attracted (to cross the vessel wall) by inflammatory responses, chemical attractants, tissue damage, or chemicals released by infected tissue.
• Lymphoid line leads to basophils, eosinophils, and neutrophils.
• One can characterize leukocytes by nucleus shape and whether or not they have granules (spottiness in the microscope).
• We want to be able to identify these cells because a differential count can give us clinically relevant clues to what is going on.

Granulocytes

• Neutrophils: stain lilac with acidic and basic dyes.
• Eosinophils: stain with acidic dyes.
• Basophils: stain with basic dyes.

Agranulocytes

• Monocytes:
  • Turn into macrophages.
  • Are not terminally differentiated.
• Lymphocytes:

• White blood cells are only a small part of the blood volume.
• Neutrophils are most abundant among WBCs in the blood, then lymphocytes, monocytes, and eosinophils.

• we'll finish Blood next time and all the readings.

• stopped here on 01/20/10.
• started here on 01/25/10.

• we probably won't finish blood today.

• Neuts are most abundant, then lymphocytes.
• The others are important, too, though.

Neutrophils

• AKA polymorphonuclear leukocytes.
• They usually last about 10 hours in the circulation unless activated to fight an infection.
• They are the most active early-on in an infection because they can be recruited very quickly.
• They are phagocytes so they can get rid of bad guys pretty quickly via hydrolytic-proteolytic enzymes.
• They can also ingest particlate matter.
• They release prostaglandins and leukotrienes which are inflammatory and chemoattractants for other leukocytes.
• Neuts have multiple types of granulocytes:
  • Those containing hydrolytic-proteolytic enzymes (to fuse to phagocytized pathogen, or to release into the tissue).
    • Note that if you release these granules, there will be tissue damage and you will have inflammation.
  • Those containing defensisns, small molecular compounds that are good at poking holes in microorganisms, thus causing it to die.
  • Granules with prostanoids (contains prostaglandins and leukotrienes) which do some tissue damage to cause inflammation and attract other white blood cells. This processes generally kills neutrophils such that pus is formed by the broken bodies of neutrophils.
• Neuts are the most motile of all granulocytes.

The tangled webs that neutrophils weave

• Explores how neutrophils can contain some of their noxious chemicals.
• The paper observed that when stimulated, the neutrophils were secreting DNA (which is very sticky) and histones and proteins beyond just the prostaglandins that we knew about.
  • Some of these things degrade bacterial virulence factors.
  • The authors also suggest that the DNA and proteins may serve to contain the tissue damage and the microbes.
• They determined that the neutrophils died when secreting all these things, but not through lysis.
• Questions that remain:
  • What are the signals that make neuts do this?
  • Why don't all neuts do this?
  • How do we control this process?

Eosinophils

• Make up only 2-4% WBCs. That is, in a normal, healthy person with no infections, etc.
• Eosinophils are less motile than neuts, but they definitely migrate.
• The cells phagocytize proteins thus detoxifying them.
• Eosinophils have oxydases, peroxidases, and phosphatases in their granules so they can release it and destroy pathogens (find out which ones).
• These cells follow chemotactants generated by an antigen-antibody interaction.
• Eosinophils can also be signaled to move by mast cells / basophils (same thing for our concerns).
• Eosinophils are increased upon allergic reactions and autoimmune diseases because of signals from basophils and antigen-antibody interactions.
• Eosinophils inactivate inflammtory chemicals like histamine (because histamine is a protein).
• Kill things too large for phagocytosis.

Basophils

• Basophils are localized whereas mast cells are systemic.
• Only 1% of the WBCs.
• Found more outside the bloodstream than inside (especially connective tissue).
• Their granules contain heparin and histamine (an anticoagulant and a vasodilator, respectively).
  • These two factors increase blood flow to an infected area, increase eosinophil and neutrophil recruitment, and increase capillary permeability.
  • This is all good when there is an infection.

Lymphocytes

• Second most abundant after neuts, 20-30%.
• Found mostly in the lymphoid peripheral tissue, not in blood.
• There are three types:
  • T cells: responsible for cell mediated immunity (directly killing other cells that are infected).
  • B cells: antibody mediated immunity (target cells for degradation).
  • Natural Killer cells: recognize global types of antigens.
• B and T cells are very specific; NK cells are not that specific.

Monocytes

• Only live for a few days in blood stream, then move into tissue.
• Originate in bone marrow.
• Only fully differentiate upon moving into tissue, into macrophages.
• Macrophages are phagocytic.
• Macrophages release chemical signals to recruit more phagocytic cells.
• There are several types of macrophages:
  • Fixed: reside in a particular tissue. Then we name them like "alveolar macrophage" or "liver macrophage".
  • Wandering: move throughout tissues.
• Macrophages are also antigen presenting cells, so they ride the fence between the innate and the adaptive immune systems.
• Microglia are the macrophages of the brain.

Differential WBC count

• This is about determining the relative amount of each type of WBC.
• You take the buffy coat and count them.
• These can support an hypothesis like those below but cannot prove any of them.
• High neuts: bacterial infection or severe tissue destruction.
  • Upon tissue damage, platelets will recruit neutrophils.
• High eosinophils: allergic reactions, parasitic infector or autoimmune disease.
  • Because mast cells and basophils recruit eosinophils.
• High basophils: allergic reaction.
• High lymphocytes: viral infection (because viruses are inside the cell, so a T cell must detect the presented antigen).
• High monocytes: viral or fungal infection.

Thrombocytes

• Platelets!
• Come from the myeloid lineage.
• The progenitor cell grows and turns into the huge megakaryocyte.
• Platelets come from parts of the megakaryocyte breaking off.
• Platelets have no nucleus but are surrounded by membranes.
• Platelet granules contain serotonin, Ca++, enyzmes, ADP, PDGF.
• Platelets aggregate and adhere to sites of vascular damage.
• Platelets are key for sealing a broken vessel by aggregation.
• This is the first line of defense for a broken vessel.
• Megakaryocytes are generated through lots of mitosis but no cell division.
• A single megakaryocyte will give off thousands of platelets.
• Thrombopoietin enhances formation of mkcyte and increases formation of platelets.

The root of platelet formation

• It is not just a random breaking apart of the mgcyte.
• There were two theories going into this research:
  • Cytoplasmic fragmentation: mgcytes have cell membranes running through them that divide the cytoplasm into the platelets and then it enters the blood stream and fragments.
  • Proplatelet elaboration: Mgcytes sit outside the blood vessels and extend processes into the blood vessels and the sheer force of the blood stream pulls off chunks of platelets.
• To distinguish between these theories, the authors:
  • engineered the mice to have fluorescent mgcytes,
  • opened marrow cavity of the brain,
  • use microscopy to watch the mgcyte, (this is hard to do in live animals)
• Visualization of the process shows that the megakaryocyte has a membrane bound inner sac and that the mgcyte's membrane runs through the endothelial wall of the vessel such that the sheer force of the blood stream pulls off chunks of the process.
• The speed of blood flow may determine how fast platelets are being broken off.

Leukopoiesis

• Generation of WBCs.
• We don't need to know all the factors for each line of WBCs.
• Colony-stimulating factors is the name giving to all the leukopoiesis factors.
• All WBCs differentiate to some degree in bone marrow.
• Lymphocytes fully differentiate in lymphoid tissue.
• Some of the CSFs are generated by macrophages and T-lyphocytes.
• Phagocytic cells have a shorter lifespan than others.
• Lymphocytes can live for years.
• Leukocytes are broken down by the liver, spleen, and lymph nodes.
• Increased WBCs generally means there is an infection.
• Leukemia is a proliferation of immature WBCs.
  • Leukemias are named for their type of precursor from which they came.

WBC physiology

• In order to fight stuff, WBCs have to get out of the circulation.
• There are different chemotactants for each type of WBC.
• Many of these signals come from other WBCs, infected tissue, or from an infectious agent itself.
• Most cells move out through the capillaries, not the main blood vessels and thus there are few cells that must be crossed by the WBCs.
• Blood and cells in it are moving rapidly, however, so we must first slow down the exiting cells.
• So first, it starts getting a little sticky such that it rolls.
• On the endothelial cells there are selectins which interact with integrins on the exiting WBCs. These interact to slow cells down and make them sticky. There must be something controlling this, however, otherwise all WBCs would leave all the time!
• Only lymphocytes can leave and reenter the blood stream; all others can only leave and die.

Adhesion Molecules: the path to a new understanding of acute inflammation

• This article says that chemical crosstalk is bidirectional between the exiting WBCs and the endothelial cells being crossed.
• Here's the process:
  • A macrophage in tissue recognizes a foreign body and is giving off soluble mediators (like histamines, interleukins, etc.).
  • The endothelial cells and WBCs are affected by the soluble mediators.
  • Selectins on the PMN move out onto the tips of the cell membrane because of the signal and then the selectins start interacting with glycoproteins on the endothelial cells. After some protein synthesis, even more selectins will be expressed.
  • Finally, the WBC binds and doesn't move.
  • Now the endothelial cell will present more immunoglobulins (fueled by inflammatory signals) such that there is tight binding. Here, integrins bind tightly to the endothelial cells after being activated by the signals from macrophages.
  • Diapedesis is mediated by e-cadherin interactions.
  • Then the WBC flattens and spreads out.
  • Then WBC migrates through the tight junction.
  • Then WBC resumes rounder shape and performs its function.

She said both have selectins.  Which cell has integrins?
*Only leukocytes.

Clinical considerations

Bone marrow transplantation

• Useful because it is enriched in stem cells.
• Useful for treatment for radiation poisoning or chemotherapeutic drug poisoning.
• It can also be useful for gene therapy because we can fix a problem and put it in the person and know that the change will be propagated.
• We need to be careful to avoid immune reaction.
  • This is about HLA typing, not ABO or Rh typing.
  • The only identical HLA types are identical twins.
  • This is a typing for the antigens on host cells that might cause an immune response. So we type as closely as possible so an immune response won't be too strong.
• There is a possibility of graft versus host disease.
  • This is the opposite of normal transplant rejection considerations.
  • With bone marrow, it is possible for the donor marrow to mount an attack against the host, and that is not good.
  • And therefore we need to remove T-cells (lymphocytes).

Alternatives to bone marrow transplantation

• As the ability to do transplants becomes more possible, it is more needed so we don't have enough bone marrow.
• But really all we need is the stem cells from bone marrow.

Clinical promise - ethical quandry

• Normally UCB (umbilical cord blood) is discarded after birth.
• UCB SCs must be typed but not as strictly because it hasn't developed all of its HLA types.
  • So it isn't as likely to cause an immune rejection.
• It has been estimated that if we just collected all the blood from every delivery, we would have all the stem cells we could need.
• Questions:
  • What's the best way to collect it and store it?
  • How long can it be stored?
  • What testing is necessary to protect the recipient?
    • Which tests do you do and how many do you do?
  • Which patient should receive the treatment until sufficient stores can be built up?
    • It is especially useful for treating childhood diseases and adults take more.
• Issues keeping us from collecting all UCB:
  • Do you need to get consent from donor parents?
  • Should testing for genetic disease be performed?
  • Should the parents be informed of the results of the genetic disease?
    • What if the disease is terminal?
    • What if the disease was chronic (diabetes) and could be affect insurance coverage?
• Other ethical issues:
  • Who should regulate the use of the material?
  • Should companies be allowed to approach parents before delivery to store cord blood when it is not known how long the blood can be stored?
    • Remember that we don't know how long it will last so maybe by 30 it's no good anymore.
• $125 annual storage fee, $1700 for kit and processing, $150 shipping service, and probably multiple thousands of dollars for a Dr. to use the kit to collect the blood.

Ubilical cord blood transplantation and banking

• An update on the previous paper.
• Stem cells are not totally free of immune response; it is still required that you do some typing.
• Partial response is acceptable and reduces the risk of GVHD.
• Banking can occur for at least 5 years. But beyond that we don't know.
• The issue of testing:
  • What is done now: HLA tissue typing, a few infectious agents.
  • No rules, no consensus, only a best practice guide by the FDA.
• UCB stem cells seem to proliferate more slowly than native HSCs.
• It is hard to use UCB in adults because it takes so many for a good transplantation. This often requires multiple sources (donors) and the two fight and one overcomes the other. However, this isn't a big problem, really.
  • During the first month, there is double chimerism: three different genetic materials--the host and the two recipients.
• HLA matching isn't as important because
• Many times these cells don't proliferate as well.

Hemostasis

• stopped here on 01/25/10.
• started here on 01/27/10.

• Hemostasis is how the blood contributes to homeostasis.
• What happens when a blood vessel is broken>?
• Four steps:

Local vasoconstriction

• This is called the vascular phase.
• Vasculature is constricted immediately.
• This slows blood loss.
• Collagen is exposed and cells release ADP, tissue factor, and prostacyclin.
• Collagen, ADP, and tissue factor and prostacyclin are important for the next two steps.

Formation of a platelet plug

• Prostaglandins, thromboxanes, and prostacyclins form the prostanoids.
  • Prostacyclins inhibit clot formation.
  • Prostaglandins encourage clot formation.
• Platelets, upon being exposed to collagen, degranulate.
• Platelets release:
  • ADP: stimulates platelet aggregation and secretion,
  • Thromboxin A2 and serotonin: stimulate vascular spasms,
  • clotting factors: proteins that play a role in clotting,
  • PDGF: helps epithelial repair,
  • Ca++: helps with the next couple of steps.
• This forms a plug by the stickifying of the membranes such that they stick to each other and to the broken cells of the endothelium and the collagen.
• So how do we limit it to the site of injury?
  • Through the release of prostacyclin (PGI2) by endothelial cells which reduces platelet coaggulation.
  • Through the breakdown of ADP by emzymes in the blood.
  • Through high levels of serotonin which block the action of ADP to further clot formation.
  • Through the fact that prostaglandins (which are encouraging clot formation) have very short half-lives in the blood so they don't react throughout the body because they are degraded before they can travel very far.
• So how does aspirin affect the clotting cascade?
  • A low dose of aspirin inhibits prostaglandins and thus decreases the platelet degranulation reaction and thus decreases plug formation.
  • A high dose of aspirin can affect the formation of PGI2 and thus decrease PGI2's ability to reduce platelet coaggulation.

Clotting cascade

• This cascade involves tens to a hundred of proteins.
• We'll only study a simple model.
• An enzyme called thrombin converts fibrinogen (soluble in the blood) to fibrin (which is an insoluble fibrous plasma protein).
• Fibrin then forms a mesh that traps RBCs and some plasma to form a clot.
• The roman numerals describe the order in which they were discovered.
• Other names have poorer logic like "christmas factor".
• There are three stages:
  • Formation of prothrombinase,
    • prothrombinase cuts thrombinogen to thrombin.
  • Conversion of prothrombin to thrombin
  • Conversion of fibrinogen to fibrin
• Intrinsic means all the factors are in the blood, extrinsic means some come from outside the blood.
• There are two ways to activate factor X: intrinsic (slower) and extrinsic (faster).
• We don't need to memorize the pathways.
• Note, however, that Ca++ and vitamin K are absolutely necessary for both intrinsic and extrinsic cascading.
• What activates intrinsic versus extrinsic.
  • Extrinsic would be factor III from a damaged endothelial cell whereas intrinsic would be factor XII from the blood.
• Common pathway:
  • Requires Ca++ (can use Ca++ chelators to stop clotting).
  • Requires vitamin K because it is required for production of many of the proteins in this cascade, like prothrombin, and factors 7, 9 and 10.
    • Vitamin K comes from bacteria in the large intestine and is absorbed as a fat soluble vitamin.
  • Factor X generates prothrombinase which then cuts prothrombin into thrombin which then cuts fibrinogen to fibrin.

Clot retraction and dissolution

• As time goes on, the clot draws together to close wound and open a vessel.
• Clot retraction is initiated by thrombosthenin, a platelet factor.
• Now we need to get rid of the clot.
• Fibrin is broken down by plasmin, a proteolytic enzyme.
• Plasminogen must be activated into plasmin.
• TPA = tissue plasminogen activator is formed by the endothelial cells and cleaves plasminogen into plasmin such that fibrin is degraded.
• Staphlokinase and streptokinase are from bacteria and used clinically to activate TPA.
• We use SK and SP to break apart clots in stroke and MI patients.

Clot busters

• SK and SP break up clots, that's their clinical use.
• However, since, SK and SP are exogenous, they can produce an immune response.
  • They are cheaper (than tPA), however, because we can get them from growing up bacteria.
• Note that SK will break down free fibrin which increases your chance of bleeding.
• Read article on our own.

Anticoagulants

• There are two types: physiological (endogenous) and therapeutic (clinically administered).
• Physiological:
  • PGI2 is a prostenoid that inhibits platelet adhesion (a prostacyclin).
  • Antithromboplastin inactivates TF3 which is part of the clotting cascade. Antitrhomboplastin normally serves to balance.
  • Factor C is similar to antithromboplastin in that it blocks TFV and TFVIII.
  • Heparin which is released by basophils / mast cells, inactivates thrombin, thromboplastin, and prothrombin.
• Therapeutics:
  • Heparin is great because it is natural and it can be reversed.
  • Calcium chelators cannot be used in vivo because it will kill them because no calcium means no neurotransmission or muscular function.
  • Warfarin or dicumarol inhibit synthesis of prothrombin by limiting use of vitamin K in the liver.
    • Warfarin won't completely inhibit clotting, so it can be titrated.

Disorders of hemostasis

Thrombocytopenia

• Low numbers of platelets.
• Can come from
  • decreased production in bone marrow from radiation or cytotoxic chemicals.
  • sequestration of platelets by the spleen
    • congestive splenomegaly: what is this?
  • destruction of platelets by autoimmune disease
    • idiopathic thrombocytopenic purpura: when the immune system breaks down the body's immune system.
• Symptoms: easy bruising because capillaries break all the time and usually platelets are the simple fix. There may also be bleeding in the joints because vessels there take a large beating.

Disseminated intravascular coagulation

• This is blood clot formation in the capillaries.
• Usually happens in respnose to bacterial infection that damages endothelial cells. This exposes collagen and starts the platelet clotting process.
• When amniotic fluid leaks into the blood stream, it can cause init of platelet and clotting cascade.
• Rarely, cancers can start this cascade.

Hemophilia

• Hemophilia A: deficiency in factor 8
  • 85%
• B: deficiency in factor IX
• C: deficiency in factor XI.
• A and B are x-linked so males are infected and women are carriers.
• C is not x linked and is not as severe.
• Symptoms include uncontrolled bleeding, subcutaneous bleeding, vessel damage in the joints, and actual damage in the joints.

Deficiencies in clotting factors

• Afibrogenemia:
  • there is a hereditary form but is usually from liver disease.
  • if the liver isn't working, then not all the clotting proteins can be made, like fibrinogen.

• Hypoprothrombinemia
  • liver disease can cause this, as can vitamin K deficiency because K is required for generation of prothrombin.
  • Hemorrahgic disease of newborns:
    • Because newborns don't have the normal bacteria in the gut that generates vitamin k or if their liver isn't fully formed, they may not be able to generate the proteins well enough.
  • Therefore it makes sense that if you are taking lots of antibiotics you may become vit k deficiency.

=Thromboembolytic disorders

• Thrombus:
  • A clot in an unbroken blood vessel which may occlude the whole vessel.
  • If the vessel is a coronary vessel, it generates a heart attack.
  • We're most worried about clots in heart, lungs and brain.

• Embolus:
  • When a clot moves to a bad location.

• Aspirin use:
  • Low doses inhibits thromboxane A2 formation and therefore platelet and aggregation.
  • In high doses, will affect PGI2 and will have the opposite affect because it inhibits the inhibitor.

• moved on to the Lymphatic / Immune notes on 01/27/10.