A novel cis-AB variant allele arising from a nucleotide substitution A796C in the B transferase gene.
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Biomedical subjects
Publications and source records attributed to J A Condon.
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A chimeric individual possesses two or more genetically distinct cell populations. Although the chimerism may not be evident in all gene systems, various loci display greater numbers of alleles than genetically "normal" individuals. The proposita was referred for further laboratory investigation due to a mixed-field ABO blood group reaction following routine antenatal testing. Various molecular (HLA class II, ABO genotyping, and 10 short tandem repeat [STR] microsatellites) and serologic (HLA class I and red cell blood groups) typing techniques were employed to investigate a number of polymorphic loci located on different chromosomes. Chimerism was identified in 8 out of the 14 chromosomes tested: chromosome 1 (Duffy), 6 (HLA class I and II), 9 (ABO), 11 (HUMTH01), 12 (HUMPLA2A1), 15 (HUMFES/FPS), 18 (Kidd) and 21 (D21S11). The proposita was determined to be a probable dispermic chimera, based on the results of the serology and molecular studies.
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Genotyping enables the identification of both maternally and paternally derived alleles. A number of protocols have been described for the genotyping of the ABO blood group system. Generally, these methods have a number of disadvantages including the use of hazardous reagents, being technically demanding, and the excessive use of materials. In this study, a relatively simple polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) method is described. Four different amplifications were used that were specific for nucleotides sites 261, 526, 703, and 796 to distinguish the A, B, O1 and O2 alleles. The ABO genotypes of 294 random individuals were determined and were found to completely correlate with the serologic phenotypes. The protocol is applicable for investigations of weak or nonexpression of ABO alleles, paternity determinations, and population analysis.
ABO polymorphism at the gene level has been investigated by molecular methods, predominantly sequencing and restriction fragment length polymorphism (RFLP). We describe the application of the polymerase chain reaction-sequence specific oligonucleotide (PCRSSO) method, which is considered to be more versatile for large sample numbers, compared with conventional ABO genotyping by PCR-RFLP. PCR-SSO, while maintaining accurate and reliable results, reduces costs and labor. A population of 155 random individuals was investigated for the three O alleles, O1, O1*, and O2. The allelic frequencies were 35 percent, 26 percent, and 5 percent, respectively. PCR-SSO results correlated completely with both serologic and PCRRFLP results.
Studies on blood samples from a 30-year-old woman of Korean origin, her husband and children, showed the presence of the cis-AB genotype in the mother and one child. The cis-AB red cells showed abnormal reactions with both polyclonal and monoclonal anti-B reagents and an elevated level of H antigen. The serum contained weak anti-B that reacted with normal B antigen but not with that on cis-AB cells. Normal levels of A substance but reduced levels of B and H substances were present in the saliva. Conversely, the serum showed reduced A and normal B and H blood group transferase activity.
A strategy using staff nurses' criticisms is described, which may be a useful addition to the repertoire of strategies used by staff development educators to elicit and meet unit-based learning needs. It is also argued that this strategy has the potential to equip staff nurses to move more independently from criticism to problem setting and problem solving.