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Pathological composition of Hb:
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Pathological composition of Hb:

HbCO (carboxyhemoglobin) – the composition of Hb with CO.

Chemical relativity of Hb to CO is in 300 times higher than O2. That’s why carbon monoxide displaces O2 from hemoglobin, decreasing the ability of the blood to bind oxygen. Even small number of CO leads to the significant increase in formation of HbCO. When concentration of the CO in the air is 0,1% - 80% Hb binds not with O2, but with CO. When concentration of CO in the air is 1%, in few seconds it will cause death.

It is dangerous because HbCO is persistent and Hb cannot transport oxygen anymore.

Low intoxication with CO is a reversible process and after breathing fresh air, CO will gradually detach. Breathing with clean oxygen has positive effect.

Normally HbCO is 1% of all the Hb. In smokers body it is 3%, after heavy pull – 10%.

Met Hb (HbOH - methemoglobin) – hemoglobin, which contains Fe3+ and has brown color. Oxidation of Fe2+ to Fe3+ in hemoglobin occurs when interacting with strong oxidizers (KMnO4, aniline), and also with medicine of oxidative properties. Insignificant oxidation of hemoglobin to methemoglobin also occurs in normal conditions. But with the help of fermenting systems of erythrocyte (NADH-methemoglobinreductase system) methemoglobin turns in to hemoglobin. Inherited absence of this fermentation can cause inherited methemoglobinemia.

In pathological conditions, when methemoglobin is formed, blood with high oxygen content circulates in the organism, but it is not entering tissues.

The amount of hemoglobin in blood of healthy human is 140-160 g/L for men, 120-140 g/L for women, 200 g/L – for newborns.

The definition of hemoglobin content:

Definition of the amount of bonded oxygen (1g of Hb can bind 1,34 ml of O2).

Analysis of iron level in blood (iron content in hemoglobin is 0,34%).

Tintometry (comparison of blood color with color of standard solution) – Sali method.

Spectrophotometry.

Method 1 and 2 require sophisticated apparatus. Third – is inaccurate. Fourth method is very popular nowadays. Blood is mixed with the solution of potassium ferricyanide, potassium cyanide, sodium bicarbonate. These substances will cause destruction of erythrocytes; Hb turns to cyan methemoglobin (HbCN). Unlike Hb, HbCN is stable and it can be stored for few weeks. The solution is rayed with monochromatic light with ? = 546nm, then extinction is defined. The content of Hb is defined by special calibration scale.

T he following showings are important in estimation of eryt forms of anemia:

Average hemoglobin content in one erythrocyte (AHC) – characterizes the absolute number of Hb in the erythrocyte.

AHC = Hb / E

Normally AHC = 26-36 picogram

When AHC is normal, than erythrocytes, they are called normochromic.

When AHC is less than normal, erythrocytes are called hypochromic.

When AHC is higher than normal, erythrocytes are called hyperchromic.

 Color index (CI) – the index which characterizes the relative content of Hb in 1 erythrocyte.

CI = Hb / first three numbers in the amount of erythrocytes

Normally CI = 0,85 – 1,15

If CI is normal, erythrocytes (and anemia) are normochromic. If CI is lower than normal – hypochromic. If CI is higher than normal – hyperchromic.

Oxygen-carrying capacity of blood (OCC) – the amount of oxygen, which is transported with 1 liter of blood

1 g of Hb can bind 1,34 ml of O2 - it is Hufner's number.

OCC = Hufner’s number • Hb (in g/l).



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