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Biomedical subjects

W R Mayr

Publications and source records attributed to W R Mayr.

At least 55 records · Page 3Linked to original sources
PubMed1999

A dispermic chimerism in a 2-year-old Caucasian boy.

Detection of two different cell populations in a child is a rare event. The following case of a dispermic chimera was diagnosed before surgery due to problems in blood group determination. A 2-year-old phenotypically male child was admitted for correction of a penoscrotal hypospadia and unilateral cryptorchism. During presurgical laboratory investigation, difficulties in blood group determination occurred. Blood group typing was performed by the DiaMed-ID Micro Typing System and by FACS. Additionally, cytogenetic analysis of lymphocytes and analysis of DNA polymorphisms in different tissues were performed. Two populations of red blood cells were detected, O cells accounting for 75% and B cells for 25%. Analysis of DNA-PCR polymorphisms in lymphocytes, nails, and in cells of the oral mucous membrane demonstrated a chimerism, with two alleles inherited from the father and one from the mother. A cytogenetic analysis of cultured lymphocytes showed a mosaic 46, XY/46,XX. Surgery revealed a prostatic utricle grade III, also called pseudovagina; genitography confirmed a vagina. Bilateral gonad biopsy showed a testis on one side and an ovary on the other. This case of chimerism represents a true hermaphroditism that most probably developed by double fertilization of one or more egg nuclei by two sperms.

Blood Grouping and Crossmatching↗
PubMed1998

Inherited platelet glycoprotein polymorphisms and a risk for coronary heart disease in young central Europeans.

Among central Europeans polymorphisms of GPIIIa, GPIb, GPIIb, and GPIa named human platelet antigen-1 (HPA-1), -2, -3, and -5 are the clinically most relevant systems in which alloimmunization occurs. These genetically determined polymorphisms of glycoproteins may render platelets sensible for plaque formation and thus could increase risk for coronary artery disease (CAD). We therefore determined gene frequencies of HPA-1, -2, -3, and -5 in European patients suffering from CAD (n = 92; median age, 46 years) or CAD accompanied by diabetes mellitus (DM) (n = 30; median age, 60 years, DM I/II, 5/25) and compared the data obtained with those in DM patients without CAD (n = 80; median age, 43 years; DM I/II, 53/27) and a control group (newborns, n = 906). Triglyceride and cholesterin levels as well as the percentage of smokers was significantly higher in the CAD group compared with the diabetics without DM (p < 0.005). No significant difference of the frequencies of any HPA-type between CAD patients with or without DM, diabetics, or controls could be detected. This was also true when evaluating a subgroup of patients aged 45 years or younger. To include a mutual influence of the described HPA-polymorphisms, we condensed the four HPA genotypes to joint glycoprotein variants. Again the same frequencies were found in patient groups and controls, when analyzing the five most common condensed joint glycoprotein variants. The analysis of the combined published studies shows that the pooled HPA-1 allele frequencies are identical in controls and CAD patients. Thus, no significant association between the polymorphisms of any of the studied HPA systems and the development of CAD can be found in central Europeans.

Adolescent↗
PubMed1998

Genetic variation and sequence studies of a highly variable short tandem repeat at the D17S976 locus.

The STR locus D17S976 was investigated by PCR amplification and native polyacrylamide gel electrophoresis in 158 unrelated Austrian Caucasians. No deviations from Hardy-Weinberg expectations were observed. The mean exclusion chance was 0.792, the discriminating power was 0.980 and the observed heterozygosity rate was 0.873. Moreover two alternative denaturing electrophoretic protocols are proposed. An allelic ladder consisting of 14 sequenced alleles (236-288 bp) was constructed. Sequence analysis revealed that the locus contained three different repeat motifs: ATCA, ATCT and ACCT, all of which vary in number between alleles. The aggregate number of the three tetrameric repeat types was used for allele designation. As a repeat with a single base deletion (ATC) was found in both the smallest and the largest alleles, a ".3" was added to the allele designation in those cases. Therefore the smallest allele is designated 19.3, and the largest allele is designated 32.3. To evaluate the exact extent of sequence variation more extensive sequence studies are necessary.

Alleles↗
PubMed1998

RHD genotyping in weak D phenotypes by multiple polymerase chain reactions.

BACKGROUND: Weak D phenotypes involve a quantitative variation of D. The genomic basis in weak D has been disputed, however. STUDY DESIGN AND METHODS: Five sequence-specific polymerase chain reactions (SSP-PCRs) on exons 2, 5, and 7 of the RHD gene were evaluated in 248 white and 98 Japanese blood donors and compared with the results obtained by amplification of intron 4 and serology. All methods and SSP-PCR testing on the 3' non-coding region of the RHD gene were applied to the genotyping of 94 DNA samples derived from individuals expressing weak D phenotypes. RESULTS: Concordant results were obtained with all genotyping and phenotyping methods in testing 201 D-positive and 145 D-negative donors. Four of 94 weak D samples were typed as D-negative by amplification of intron 4 and SSP-PCR on exon 5. Phenotyping with monoclonal antibodies revealed a DVI category in one of these cases and DFR phenotype in three of these cases. One weak D sample, which reacted like normal D-positive cells with all applied monoclonal antibodies, was typed falsely negative by SSP-PCR on exon 5 because of a point mutation at nucleotide 667 (T-->G) that resulted in a Phe223Val amino acid substitution. In this individual, heterozygosity was found at two other amino acid positions (Glu233Gln and Val238Met) by restriction fragment length polymorphism analysis. CONCLUSION: Genetic diversity in weak D phenotypes is rare. Only 1 of 90 true weak D phenotypes (1.1%) had a genetic variation in testing on seven gene regions of the RHD gene.

Asian People↗
PubMed1998

DNA recommendations 1997 of the International Society for Forensic Genetics.

The DNA commission of the International Society for Forensic Haemogenetics (ISFH) has over the years published a series of documents providing guidelines and recommendations concerning the application of DNA polymorphisms to problems of identification. This latest report provides recommendations relating to the nomenclature of short tandem repeat system (STR) typing systems which are at the forefront of systems used at present by forensic scientists and are likely to remain so for the immediate future.

Alleles↗
PubMed1997

Additional variability at the D12S391 STR locus in an Austrian population sample: sequencing data and allele distribution.

The highly polymorphic STR locus D12S391 was investigated in an Austrian population sample (N = 150) by PCR-amplification, comparative detection on native and denaturing polyacrylamide gels and solid phase single stranded sequencing of three size variant alleles and several additional alleles. A total of 15 alleles, distinguishable by size under denaturing conditions, could be detected. No deviations from Hardy-Weinberg equilibrium were observed in the population investigated (P = 0.52). Sequencing of size variants designated 17.3 and 18.3 showed an incomplete (GAT) repeat unit at position two of the tandem region. Additional new sequence variants due to varying compositions of the number of (AGAT) and (AGAC) repeats could be identified. Due to distinct electrophoretical mobilities of alleles of the same size but different sequence structures, denaturing detection conditions should be employed when the aim is standardization.

Alleles↗
PubMed1997

Target platelet antigens of autoantibodies in patients with primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is an autoimmune disease of the liver, frequently associated with thrombocytopenia. As various immune abnormalities have been described in PBC, we hypothesized that thrombocytopenia is also an autoimmune phenomenon in these patients. We therefore assessed the frequency of platelet antibodies and their target platelet glycoprotein (GP) specificities. We investigated 66 PBC patients with a median disease duration of 25 months. Twenty-two patients with alcoholic liver disease and thrombocytopenia served as controls. Specificities of platelet antibodies were determined by the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay using monoclonal antibodies directed against GPIIb/IIIa and GPIb/IX. The notion that immunoglobulins are nonspecifically bound to platelets was further evaluated by the production of eluates from antibody-coated platelets. The specificities of antibodies in these eluates were again determined by the MAIPA assay. Twenty-six PBC patients had platelet antibodies, whereas antibodies were not detectable in control alcoholic patients. Seven of 13 thrombocytopenic PBC patients had detectable antibodies. Overall, GP Ib/IX and GP IIb/IIIa served in a similar frequency as target antigens. Antibody specificities were confirmed by the production of eluates from platelets. These studies provide evidence that antibodies are specifically bound to platelets in patients with PBC and that the development of immune phenomena in PBC may also involve immuno-mediated platelet destruction.

Adult↗
PubMed1997

A new allele at the short tandem repeat locus HumF13A01.

We investigated the (AAAG)n short tandem repeat (STR) polymorphism HumF13A01 an Austrian Caucasoid population sample (n = 674). PCR amplified fragments were detected on an automatic A.L.F. DNA sequencer using laser-induced fluorescence. A total of 14 alleles could be identified including a new 179 bp allele which was designated allele 3. Sequence determination of allele 3 confirmed the typing results by revealing three continuous copies of the core repeat, whereas in sequencing of 54 additional alleles no further variants or microheterogeneities could be observed. The population data showed no significant deviation from Hardy-Weinberg equilibrium.

Austria↗
PubMed1997

Lupus anticoagulants: strong association with the major histocompatibility complex class II and platelet antibodies.

A relationship between the presence of platelet autoantibodies and major histocompatibilty complex class II alleles was determined in 27 patients with lupus anticoagulants. Twenty-two patients had a primary antiphospholipid syndrome' and five patients had lupus erythematosus (SLE). Platelet antibodies against the platelet glycoproteins (GP) IIb/IIIa were detectable in 20 patients. Anti-GPIb/IX or -GPIV antibodies were detectable only in patients with anti-GPIIb/IIIa antibodies. An increased frequency of HLA-DQB1*06 was demonstrable in the total patient population. The association between the lupus anticoagulants and HLA-DQB1*06 was even stronger if patients also had detectable platelet antibodies. This association was also seen if patients with a history of thromboembolic disease were considered separately. However, within the patient population there was no difference between frequencies of HLA alleles detectable platelet antibodies.

Adolescent↗