category: Medicine, health

Rhesus Factor and rhesus conflict

"lost money - sorry, lost time - angry, lost his health - hopeless ".

G. Ratner.

Title "Rh factor" comes from the name of the form monkeys - rhesus monkeys. In 1940 Australian scientist Karl Landsteiner (he in 1900 opened blood group, for which in 1930 received the Nobel Prize) and U.S. AS scientists Wiener in red blood cells of the monkey was detected antigen called the Rhesus factor.

presence or the absence of Rh factor in human red blood cells causes them to belong Rhesus positive (Rh +) or Rhesus negative (Rh-) group.

found that 86% of people caucasian (white) race have Rh-positive (99% of Indians and Asians), and 14% - rhesus negative factor (7% of Africans).

Rhesus affiliation does not change during the life of man.

"Rh-positive" properties of blood due to the influence of a dominant gene, and "Rh-negative" - a recessive gene.

Blood "Rh-positive and Rh-negative" people incompatible. Because if it enters the blood, Rh-negative " individual Rh factor antigen induces the formation of antibodies (immune reaction), which may lead to a serious condition as anaphylactic shock.

"Rhesus negative" patients could transfuse only "Rh negative" blood, "Rh-positive" - as "Rh positive" and "Rh-negative.

Rhesus-conflict mother and fetus

In Marriage a man who has Rh-positive factor, and women with Rh-negative factor may be increasingly conceived "Rh-positive" fruit.

fetal antigens during pregnancy in a small number are able to penetrate into the bloodstream mother through the placenta and cause the formation of antibodies (especially if there pathology of child seats). In the first pregnancy (and sometimes in the second) their concentration in blood is relatively low and the embryo develops, not experiencing the harmful effects of these antibodies. Painting

sharply changes in subsequent pregnancies: the concentration of antibodies more and more increases, due to the small size they are able to freely penetrate placenta into the bloodstream and damage to the fetus Rh-positive erythrocytes (hemolysis) and blood-forming organs. The result is the emergence of a Child hemolytic disease.

In early manifestation of the disease Rhesus-conflict may be the cause of preterm birth or miscarriage, and stillbirth. Analysis of Rhesus-conflict typically produce at the 8th week of pregnancy and determine the presence Rh antibodies in the blood. This is especially important if in the past have abortions, miscarriages or performed a blood transfusion.

Today time medicine has ways to combat the hemolytic disease in the form rapid transfusion of infant rhesus negative blood or the introduction anti-Rh-antibodies for prevention of maternal immunization.

If "Rhesus negative" woman wants to have a second or third Child of "rhesus positive" men, then she must consult a doctor and be screened for the presence of Rh antibodies in blood.

Something interesting

If little deeper, I can tell you that the Rh factor is only one multiple antigens that make up the system of Rh. Ie erythrocytes each Rights contain a complex of Rh antigens, consisting of three pairs of antigens. Different combinations of these 6 antigens make up the 27 groups of rhesus. But everyday medical practice, the definition of these groups (which in itself is important blood transfusion donor recipient) is impossible because of extreme rarity antisera (some of them are even hypothetical).

therefore more actual definition of three antigens, which may be present in erythrocytes Rights, together or separately, forming 7 different combinations, which including possible lack of red blood cells of all 3 of these antigens are 8 major groups of rhesus. And

. What As for natural selection in evolution. So, scientists believe that death of a newborn as a result of hemolytic disease (if not medical care) is a form of natural selection (performing stabilization fund and the maintenance of genetic inheritance diversity).

So in "Rhesus negative" mother "rhesus positive" fruit always the heterozygote, ie, has both a recessive (Rh-) and dominant (Rh +) allele. This means that with the death of the individual from the gene pool of populations removed an equal number of alleles "Rh.

selection in this If directed against heterozygotes. And as the dominant genes more than recessive in a population, then such selection gradually leads to a decrease in the proportion rarer (Rh-). It is estimated that the decline in its share from 14% (Europeans) to 1% by selection against heterozygotes would require 600 generations, or about 15000 years.

List References

To prepare This work has benefited from medicinform.net/


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