hematology student notes

Some of the many Functions of Plasma Proteins

1) they maintain oncotic (osmotic) pressure.

2) they buffer for optimal pH

3) they are antibodies

4) they are hormones

5) they transport steroid and thyroid-calorigenic hormones

6) they transport metals, ions, fatty acids, amino acids,bilirubin and heme

7) they are plasma enzymes (e.g., renin, thrombin)

8) they provide for clotting (and fibrinolytic) reactions

9) they are substrates for many plasma reactions (e.g.,angiotensinogen)

Just some of the Liver’s Contributions to Plasma Proteins

Albumin Binding & carrierproteins, osmotic reg.

Hemopexin Binds to porphyrins,heme, for recycling

Orosomucoid uncertain Transferrin Transport of iron

1-Antiprotease Trypsin, and general

protease inhibitorApolipoprotein B Assembly of

lipoproteins-Fetoprotein Binding & carrier

proteins, osmotic reg.Angiotensinogen Precursor to

Angtiotensin I

2-Macroglobulin Inhibitor of serumendoproteases

Most clottingfactors

Blood clotting

Antithrombin-III Protease inhibitor ofclotting system

Protein C Fibrinolytic system

Ceruloplasmin Transport of copper IGFs growth factors

C-reactive prot. uncertain – possiblywith tissue inflam.

Steroid hormonebinding globulin

carrier proteins forsteroid hormones

Fibrinogen Precursor of Fibrin Thryoxinebinding hormone

carrier proteins forcalorigen. hormones

Haptoglobin Binding/transport of Hb Transthyretin carrier proteins forcalorigen. hormones

denotes those we will, or have already, learned about.

Classification and appearance of leukocytes

Granulocytes (has cytoplasmic granules, lobed nucleus)

Neutrophils – stains “neutrally” – active “microphage”

Eosinophils – stains with a predominance of Eosin (one of twocomponents of Wright’s Stain, a classic stain) – secretes toxiccompounds to combat larger foreign entities, e.g., parasites.

Basophils – stains with a predominance of Methylene Blue (theother component of Wright’s) – contribute to inflammation, andto allergic reactions.

Agranulocytes (those without cytoplasmic granules )

Lymphocytes – those that have an ovoid nucleus – expressesthe immune response (cellular by T’s, humoral by B’s).

Monocytes – wandering “Macrophages” (as well as precursor ofpolynuclear or “fused cell” Osteoclasts, etc.) – “half-moon”nucleus – “scouts” for antigens to alert the immune system.

Dig. enzymes

Blood Cell Pathology

Leukocytes

Leukopenia too few (due to poison, radiation, etc.)

Leukocytosis too many

Physiological e.g., response to stress

Pathological infection, or ….

…Leukemia

Myeloid of granulocytes

Lymphoid of agranulocytes

Erythrocytes size and shape

very highlowest SA / V SA / V ratio

ratio

Compromise unoxygenated high volume

(wasted) Hb but lesswaste of Hb

min. diffusion that is withindistance

for the time in capillaries

for the reaction: Hb + O2 HbO (“oxyhemoglobin”)

Now, let’s substitute Hb and oxygen for this reaction,

HbO

Depend.Variable

Independent Variable O2

Although Fe serves as the primary “attractant” ofO2 , hemoglobin’s polypeptides serve as enzymesto control the reactions of the Fe atom:

1) the reaction of Fe with O2 is usually (inorganic) one-way(i.e., not readily reversible)! This would not be suitable – the Fe inside Hb, after itbecome HbO, would not release O2 to the cells!

2) the expected linearity of a typical reversible reaction isbetter (for biological purposes) altered to a sigmoid curve, called the Hemoglobin Dissociation Curve: (a) to“load” O2 over a wider range of concentrations, and (b)to readily release O2 in the “tissue” range of conditions.

Hb also serves additional, less critical functions:e.g., helping CO2 transport; as a buffer; etc.

Hemoglobin Dissociation Curve

The amountof Hb that iscombinedwith O2 as“HbO”.

The abundance of O2 moleculesin the tissues surrounding the blood.

How to describe Oxygen Abundance? Instead of needing to use two factors, Concentration and

Pressure, at the same time to measure the availability of oxygen, we should pursue a single parameter (it makes graphing easier).

Based on Dalton’s Law (from your chem class?) there is such aparameter. Physiologists use a measure called PARTIAL PRESSURE (e.g., “ pO2 ”) – a single value that incorporates pressure and concentration to create a physiologicallymeaningful measure of oxygen abundance.

It is quantified, simply*, as the product of the concentration of agas in the air times the total pressure:

Partial Pressure = A (proportion, as a decimal) X B (total pressure, in mm Hg)

e.g., the pO2 of our air, at sea level, is calculated as:pO2 = 0.20 X 760mm Hg = ~ 152mm Hg

* for gases dissolved in water, solubility makes this more complex

Hemoglobin Dissociation Curve

100%(saturated)

% HbOof total Hb

e.g.:muscles e.g.: lungs

low pO2 high

Altitude vs. Pressures

Note: Pressures are not linear withaltitude because air is compressible

total atmos.pressure

alt. (ft.) comments psi mm Hg pO2

0 sea level 14.7 760 1526,000 suitable for altitude athletic training 11.6 600 120

10,000 start of effects of “Mtn. Sickness” 10.0 517 10316,000 physiological limit for acclimation 7.9 400 8020,000 top of Mt. McKinley (Denali), AK 6.6 340 6824,000 beginning of the “Death Zone” 5.0 260 5229,000 top of Mt. Everest, Tibet 4.6 240 48

One of the most common physiological compensations(i.e., modes of acclimation) that occurs is SecondaryPolycythemia – an increase in Erythropoietin (EPO, a hormone that regulates the rate of erythrocyte production)by the Kidneys results in an increased Erythrocyte count –thus increasing the amount of O2 that is carried in theblood.

Remember what causes the TERTIARY structure of a protein?…(note: the 3° structure is responsible for much ofa protein’s enzymatic activity)

There are four factors, and two are constant (environment-independent):

Hydrophilic/-phobic

Disulfide bonds,

We don’t have to concern ourselves

The other two factors determining the TERTIARY structure of a protein are variable (environment-dependent):

Hydrogen bonding between certain amino acids

These bonds vary their strength, and the pull(and distance) between amino acids, as a functionof temperature, giving proteins (or enzymes) temperature dependent characteristics

Reminder: Didn’t you do experiments in General Biology (you did when I taught it) on enzyme temperature dependence?

and

Zwitterion Effect! Any “old” students rememberthis from last term?????

Zwitterion Effect

Certain Amino Acids change their charge as a function ofpH

+ isoelectric points of variouselectro- example amino acidsstaticcharge 0

-pH

Thus, the charges and resulting electrostatic attractionbetween amino acids can vary with different pH, andenzymes will assume different 3° structure, andcharacteristics, in different pH environments.

When do you encounter decreased pH, increasedtemperature, or increased CO2?

When tissues are very active (e.g., muscles working hard):

1) they generate more heat and warm the blood.

2) they release more CO2 into the blood.

3) they may even become anaerobic and release lactic acid– this, and the carbon dioxide, too, lowers the pH.

Thus, the very things (above) that metabolically very activetissues, which need more oxygen, do to the blood are alsoexactly what changes Hb to release more oxygen thanusual.

Fetal Production of HbF

switching, and the genes for these Production p.p.’s, are on chromosome 11.Rate

polypeptide polypeptide

it takes time for the Hb’s to change

(it’s changed in about 4 mos.)

AgeGestation Parturition

(birth)

HbF combines and (2

2) HbA combines with

Fetal Hemoglobin Dissociation Curve

wants toload O2

% HbOof total Hb

The Placenta’senvironment

wants torelease O2

pO2

Myoglobin Dissociation Curves

wants toload O2

Myoglobinreadily loads,

% HbO and stores, O2

of total Hb in muscles andother tissues,only reluctantlyreleasing it atthe lowest pO2

levels – in direwants to emergencies:release O2 near anoxia!

Near Anaerobic pO2

Effects of Carbon Monoxide (CO)

wants toload O2

The problem withCO poisoning is Dose?

% HbO that it both reducesof total Hb capacity to carry

O2 and release Hbit to tissues –anoxia

“Hb limited?”wants torelease O2

pO2

Erythrocyte Pathologies

Anemias (Type: insufficient RBCs):

Iron deficiency lacks Fe

Aplastic slow hemopoietic tissue production(due to poison, radiation, etc.)

Hemolytic too rapid hepatic breakdown

Hemorrhagic blood loss has lost RBCs – the fluidportion (plasma) is replaced faster,leaving a low RBC count

Pernicious results similar to Aplastic, butbecause of a specific deficiency(e.g., Vit. B12)

The RBC count is a balance between rate of production and rate of destruction

Normal RBC productionis indicated by findingabout 1% Reticulocytes


Anemias (Type: defective Hemoglobin):

Thalassemias (normal polypeptides, but in deficient amounts (a gene “regulatory” problem – e.g., insufficent gene expression of or chains results in overall shortage of Hb)

Hemoglobinopathies (abnormal polypeptide chains):

HbA is normal, in comparison to, e.g., HbC, HbG (SanJose), HbM (Saskatoon), HbO (Arabia), etc. – example:HbS has abnormal chains – they polymerize at lowpO2 levels and distort and stiffen erythrocytes (“Sickle-cell”) – though offer resistance to malaria.

HbF (fetal Hb) – some individuals don’t stop making it.


Polcythemias (too many RBCs):

Primary (1º), a.k.a., “Polycythemia vera”and “Hyperplasia” – cellular pathology:

blood cells (often, leukocytes as well aserythrocytes) are produced too rapidly.

Secondary (2º) – usually temporary or environmental an overproduction due to increases in EPO

(e.g., a low pO2 environment)

release of extra RBCs stored in the Spleen(e.g., stress, Sympathetic ANS stimulation)

The kidney’s production of EPO, and its effect on bonemarrow, can vary RBC production as much as 5-fold.

Erythrocyte Blood Types

There are about a dozen systems just for Erythrocytes,including ABO, Rh, MNS, Lutheran, Kell, and Kidd (there are manymore for Leukocytes, viz., Human Leukocyte Antigens, or HLAs).All but one of these Erythrocyte systems are somatic (i.e., Xg issex-linked).

For the ABO system, often taught in Gen. Biol., note that thereare really two A variants, A1 and A2 (the latter is a very weakantigen, often confused with “O”); there is also an “H” antigen, aprecursor of both A and B antigens that is missing in type Oindividuals, that shows up in tests.

Under the Rh system, also taught in Gen. Biol., there areactually three major variations, C (i.e., C and c alleles), D and E. The D variation is most significant.

Blood typing’s main importance is, in transfusing blood, the clinical danger of emboli and hemolytic transfusion reactions (i.e., releasing the contents of hemolyzed erythrocytes) leading tojaundice and renal tubular damage, anuria, and death.

ABO (simplified – e.g., no A1 or A 2 distinctions)

The locus for this system is symbolized as I or H.

Using the former, there are three alleles, IA, IB,and II ; or A, B, and O,respectively (but the latter are often confused with phenotypes, so Iprefer the former). IA and IB are dominant; Ii is recessive.

The first two alleles code for oligosaccharide antigens, a.k.a. agglutinogens (i.e., substances that can induce an immune response),that we’ll call A and B. II does not produce any antigen – there is no O.

Antibodies, or agglutinins, against these antigens are called anti-Aand anti-B; obviously, there is no anti-O.

Genotypes IAIA IAIi IBIB IBIi IAIB IiIi

Antigens present A B A & B none

Phenotype A B AB ODonate blood to A & AB B & AB AB all

Antibodies? anti-B anti-A none both Accept blood from A & O B & O all O

Why do, e.g., type A individuals innately have anti-B antibodies?

Rh (using the D system as an example)

Simple mendelian, autosomal, 2-allele, dominant/recessive, inheritance:

DD and Dd are both phenotype Rh+ and produce the antigen D; dd is phenotype Rh- and produces no antigen.

There is for Rh, however, an additional clinicalsignificance beyond transfusion – pregnancy. Anti-Dagglutinins or antibodies can cross the placenta and causeErythroblastosis fetalis, or “Hemolytic disease of thenewborn”. The fetus may die in utero, or develop anemia , severe jaundice (not the more typical temporary jaundice of newborns that’s simply corrected by UV lights), edema (Hydrops fetalis), or Kernicterus (bilirubin deposits in basal ganglia – because of immature blood-brain barrier –producing severe CNS deficit).

Concerned yet?

Rh (using the D system as an example)

Scenario:

Required: Mother is dd, Rh- ; father is D– (the dash signifies that it may be D or d, i.e., that he may behomozygous dominant or heterozygous), in any case Rh+.

Then, the mother, being Rh-, might* produce antibodiesagainst a fetus that is Rh+ (only possible with a Rh+ father –if he’s homozygous, the chance of the fetus being Rh+ is100%; if he’s heterozygous, the chance is 50%).

* An Rh- mother does not innately have anti-Rh antibodies; only by prior exposure to D antigen (earlier pregnancy with an Rh+ fetus without treatment, improper transfusion, etc.).

Hemostasis

There are THREE components to preventing blood loss:

1) Vascular Spasm – the blood vessels’ walls (smoothmuscle) vigorously contract to reduce the flow rate ofbleeding.

2) Platelet aggregation – platelets adhere to each otheraround the site of a vessel leak (aspirin reduces theirstickiness, making such small bleedings more frequent).

3) Blood clotting – a series of reactions produces a Fibrin(essentially, precipitated Fibrinogen) net-like matrix thatentraps blood cells and forms a “clot”. This is a balance between two systems, Clotting vs. Fibrolysis.

Some Blood Clotting Factors

I Fibrinogen X Stuart-Prower FactorII Prothrombin XI Plasma Thromboplastin

Antecedent (PTA)III Thromboplastin XII Hageman (glass) factorIV Ca++ XIII Fibrin-stabilizing factorV Proaccelerin HMW

-KLaki-Lorand Factor

VII Proconvertin, SPCA Pre-K Prekallikrein, Fletcher FactorVIII Antihemophiliac Factor Ka Kallikrein FactorIX Plasma thromboplastic

Component (PTC)PL Platelet Phospholipid

there is no factor VI

The Fibrolytic System

You probably learned about the just-shown clottingsystem in Gen. Biol., but this Fibrolytic System is usuallyignored in such texts despite its importance.

Thrombomodulin + Thrombin(on endothelial surfaces)

Prot. C Activated Prot. C (APC)

inactivates VIII,Antihemophiliac factor

inactivates V,Proaccelerin

inactivates inhibitor of t-PA,“Tissue Plasminogen Activator”

Plasminogen Plasmin, (a.k.a.

Fibrinolysin) lyses FIBRIN

Note: I’m sure that you’vealready heard of t-PA as anew treatment for CVAs.

Some Anticoagulants

Chelating Agents:Removes Ca++

Coumarins (Warfarins):blocks four different factors, II (Prothrombin), VII, IX,and X which would promote clotting, and alsofacilitates actions of prot. C which promotesfibrinolysis; ; also blocks the action of Vit. K (anecessary clotting cofactor); and slows the liver’sproduction of Fibrinogen.

Heparin:blocks Thrombin, and helps antithrombin III, a factorthat binds to several clotting factors, preventing theirinvolvement in the clotting process.

Some Hemostasis disorders, including Hemophilia

Diminished clotting ability:I Afibrinogenemia temporary depletionII Hypoprothrombinemia decreased synthsis,

usually from Vit. K def.V Parahemophilia inheritedVII Hypoconvertinemia inheritedVIII Hemophilia A (classic) X-linked inheritedIX Hemophilia B (“Xmas”) X-linked inheritedX Stuart-Prower factor inheritedXI t-PA deficiency inheritedXII Hagerman trait inheritedvon Willebrand factor von Willebrand’s dis. inherited

Diminished ability to dissolve clots:V (again) APC resistance inheritedProtein S Protein S deficiency inheritedProtein C (for breakingdown Fibrin)

Protein C deficiency inherited

hematology student notes

Documents