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They say they have safety measures in place to make donors safe. Learn more about platelet-rich plasma PRP injections, including what they're used for, how much they cost, and what to expect. Blood is a lot more complex than it looks. Learn more about the different types of blood, including which one is the rarest and the role of genetics…. How often can you donate plasma? Learn how frequently you can donate, who's eligible to donate, how it compares to donating blood, and possible side….
Donating blood comes with a few restrictions, including if you have herpes. Health Conditions Discover Plan Connect. Blood Typing. Medically reviewed by Deborah Weatherspoon, Ph. The blood types. Why blood typing is done. The risks of blood typing.
How to prepare for blood typing. How blood typing is performed. However, clerical error can result in "the wrong blood" being transfused into a patient, an error which can result in the death of the patient 7, 8. If a recipient who has blood group O is transfused with non-group O RBCs, the naturally occurring anti-A and anti-B in the recipient's serum binds to their corresponding antigens on the transfused RBCs.
These antibodies fix complement and cause rapid intravascular hemolysis, triggering an acute hemolytic transfusion reaction that can cause disseminated intravascular coagulation, shock, acute renal failure, and death. Anti-A1 is a less significant cause of transfusion reactions and does not appear to fix complement. Cases of severe hemolysis that require exchange transfusions are less common, and fetal hydrops is rare 9. This is because the anti-A and anti-B formed in group O individuals tend to be of the IgG type and therefore can cross the placenta , whereas the anti-A and anti-B found in the serum of group B and A individuals, respectively, tends to be of the IgM type.
Although uncommon, cases of HDN have been reported in infants born to mothers with blood group A2 11 and blood group B However, the strength of fetal ABO blood group antigens can vary, and therefore the degree of hemolysis and hence the severity of HDN can be unpredictable However, later studies showed that the prevalence of disease that required treatment did not differ significantly among Asian, Black, Hispanic, and Caucasian infants In saliva and other bodily secretions, the enzyme that synthesizes the H antigen is encoded by the Se locus FUT2.
The ABO locus is located on chromosome 9 at 9q It contains 7 exons that span more than 18 kb of genomic DNA. Exon 7 is the largest and contains most of the coding sequence.
Exon 6 contains the deletion that is found in most O alleles and results in a loss of enzymatic activity. The residues at positions and determine the A or B specificity of the glycosyltransferase they encode The O allele differs from the A allele by deletion of guanine at position The deletion causes a frameshift and results in translation of an almost entirely different protein that lacks enzymatic activity There are many variant ABO alleles that encode a number of variant ABO phenotypes, but they do not encode specific antigens other than the A and B antigens.
The H locus is located on chromosome 19 at 19q It contains three exons that span more than 5 kb of genomic DNA, and it encodes a fucosyltransferase that produces the H antigen on RBCs. Therefore, their serum contains anti-A and anti-B, in addition to potent anti-H.
This rare phenotype of H-deficient RBCs is called the "Bombay phenotype" O h after the city in which it was first discovered. Individuals with the Bombay phenotype are healthy, but if they ever needed a blood transfusion, the antibodies in their serum would place them at a high risk of having an acute hemolytic transfusion reaction. This can be avoided by using only blood products from a donor who also has the Bombay phenotype usually a relative.
The Se locus is located on chromosome 19 at 19q It contains two exons that span about 25 kb of genomic DNA. The Se locus encodes a specific fucosyltransferase that is expressed in the epithelia of secretory tissues, such as salivary glands, the gastrointestinal tract, and the respiratory tract. The enzyme it encodes catalyzes the production of H antigen in bodily secretions. They are unable to produce a soluble form of H antigen and hence do not produce A and B antigens.
Turn recording back on. National Center for Biotechnology Information , U. Show details Dean L. Search term. Chapter 5 The ABO blood group. Antigen-carrying molecules Glycoproteins and glycolipids of unknown function The ABO blood group antigens are attached to oligosaccharide chains that project above the RBC surface. These chains are attached to proteins and lipids that lie in the RBC membrane.
The A and B alleles each encode a glycosyltransferase that catalyzes the final step in the synthesis of the A and B antigen, respectively. The O allele encodes an inactive glycosyltransferase that leaves the ABO antigen precursor the H antigen unmodified. Anti-A is found in the serum of people with blood groups O and B.
Anti-B is found in the serum of people with blood groups O and A. Antibody reactivity Capable of hemolysis Anti-A and anti-B bind to RBCs and activate the complement cascade, which lyses the RBCs while they are still in the circulation intravascular hemolysis. Transfusion reaction Yes — typically causes an acute hemolytic transfusion reaction Most deaths caused by blood transfusion are the result of transfusing ABO-incompatible blood.
Most cases are mild and do not require treatment. Background information History At the beginning of the 20th century an Austrian scientist, Karl Landsteiner, noted that the RBCs of some individuals were agglutinated by the serum from other individuals. Nomenclature Number of ABO blood group antigens: 4. Expression Although the ABO blood group antigens are regarded as RBC antigens, they are actually expressed on a wide variety of human tissues and are present on most epithelial and endothelial cells.
Diseases associated with ABO blood group antigens No diseases are known to result from the lack of expression of ABO blood group antigens, but the susceptibility to a number of diseases has been linked with a person's ABO phenotype. Clinical significance of ABO antibodies ABO antibodies are of major clinical significance for two reasons: they are naturally occurring and are found universally, and, they are highly reactive. Transfusion reactions The routine practice of blood typing and cross matching blood products should prevent adverse transfusion reactions caused by ABO antibodies.
Hemolytic disease of the newborn Most cases of hemolytic disease of the newborn HDN that arise from an ABO incompatibility require no treatment. Read more about the Hh blood group in Chapter 6. For example, people of Asian origin have a higher frequency of group B than white Europeans.
Individuals of blood group O are sometimes known as universal donors as their red cells have no A or B antigens. However, their plasma does contain anti-A and anti-B that, if present in high titre, has the potential to haemolyse the red cells of certain non-group O recipients see below.
ABO-incompatible red cell transfusion is often fatal and its prevention is the most important step in clinical transfusion practice Chapter 5.
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