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Biomedical subjects

W R Mayr

Publications and source records attributed to W R Mayr.

At least 163 records · Page 9Linked to original sources
PubMed1986

The use of DNA polymorphisms demonstrated by means of the HLA system.

The advances reached by using DNA polymorphisms (restriction fragment length polymorphisms) in blood group serology are demonstrated by means of the HLA system. The potentialities for various applications (e.g. better definition of alloantigens, association with diseases, paternity testing, forensic medicine or genetic counselling) are mentioned.

DNA↗
PubMed1986

Heterogeneity of hereditary motor and sensory neuropathy type I (HMSN I): electroneurographical findings, visual evoked potentials and blood group markers in a family with Charcot-Marie-Tooth disease (CMT).

21 members of a large kinship with autosomal dominant CMT showing typical clinical findings were studied electroneurographically, with visual evoked potentials (VEP) and with blood group markers. In clinically affected members, the mean motor nerve conduction velocity (NCV) of the median nerve was found to be 17.5 m/s (SD 2.4). Contrary to previous genetic linkage studies in CMT families with comparable slow motor NCV, blood group typing in this family excluded close linkage of HMSN I to Duffy locus, which may indicate the existence of another subgroup in CMT neuropathy. Mean latencies of VEP, in both clinically affected and unaffected members, showed no pathological alterations when compared to normals. There was no correlation between NCV and P 100 latencies, but significant variation of P 100 latencies in families of twin brothers could be demonstrated. As already suggested by other authors, our findings may also indicate heterogeneity in this neuropathy.

Charcot-Marie-Tooth Disease↗
PubMed1986

Platelet-associated immunoglobulins IgG, IgM, IgA and complement C3c in chronic idiopathic autoimmune thrombocytopenia: relation to the sequestration pattern of 111indium labelled platelets.

Levels of platelet-associated immunoglobulins (PAIg) IgG, IgM, IgA and complement C3c were related to parameters of 111Indium-labelled platelet kinetics in 17 patients with chronic idiopathic autoimmune thrombocytopenia (cAITP). Elevated levels of PAIg/C3c were found in 14 patients (82%) (PAIgG n = 13, PAIgM n = 11, PAIgA n = 1, PAC3c n = 5). Only PAIgG correlated with platelet counts (RS = -0.71, p less than 0.01). Mean platelet life span (MLS) was shortened in all patients (median 12.0 h, range 0.3-45.6 h) and correlated with the platelet counts (RS = 0.49, p less than 0.05). MLS was correlated with PAIgG (RS = -0.52, p less than 0.05), but not with PAIgM, PAIgA, or PAC3c. The site of sequestration was splenic in 10 patients and splenic-hepatic in 7 patients. Although no significant correlation between either site of platelet sequestration and any of the investigated PAIg/C3c was demonstrable, platelets coated with higher PAIgG levels were more readily sequestrated in the spleen, while elevations of PAC3c were found in 4 out of 7 patients with hepatic involvement.

Adolescent↗
PubMed1986

[Heterogeneity of neural muscular atrophies].

Classification of the hereditary motor and sensory neuropathies is discussed and findings reported in the recent literature are compared to our own findings in a kinship with autosomal dominant CMT. Previous studies in CMT-families with comparable slow nerve conduction velocities had shown positive linkage of this hereditary neuropathy to the Duffy blood group locus; however, blood group typing in the recently studied kinship excluded close linkage, which may indicate the existence of another sub-group in this entity. Testing of visually evoked potentials in this kindred demonstrated significant differences in P 100 latencies of the families of twin brothers. This intrafamilial difference may also be an expression of heterogeneity.

Charcot-Marie-Tooth Disease↗
PubMed1985

Coxsackie-B-virus-specific IgM responses, complement-fixing islet-cell antibodies, HLA DR antigens, and C-peptide secretion in insulin-dependent diabetes mellitus.

To evaluate the role of Coxsackie B viruses in the pathogenesis of insulin-dependent (juvenile-onset, type 1) diabetes mellitus (IDDM), attempts were made to correlate virus-specific IgM responses with HLA genes, autoimmune responses, and C-peptide secretion. HLA DR3, DR4, or both were present in 73 of 90 (81%) diabetic patients; 22 of 23 (96%) with Coxsackie-B-virus-specific IgM had at least one of these HLA types, compared with 51 of 67 (76%) without virus-specific IgM. There was no correlation between HLA A, B, or C types or immunoglobulin allotypes and virus-specific IgM responses. 16 of 22 (64%) patients with Coxsackie-B-virus-specific IgM compared with 26 of 72 (36%) without had complement-fixing islet-cell antibodies; no relation was found between virus-specific IgM and antibodies against thyroid or adrenal tissue or parietal cells. C-peptide secretion was significantly lower in patients with Coxsackie-B-virus-specific IgM.

Adolescent↗
PubMed1985

Genetic and population structure of four Sardinian villages.

Data on microgeographic population structure on four neighbouring villages of Sardinia island (Italy) are presented and discussed. Two villages are located in the lowlands where malaria from Plasmodium falciparum was endemic until the eradication of paludism. The other two villages are located in the highlands and they were malaria-free because of the altitude. Census data, inbreeding, migration matrices and surname distributions have been collected. The genetic differentiation of the four villages, tested for 31 genetic polymorphisms (106 alleles), is only in part compatible with migration rates inferred from demographic data. The possible adaptive nature of some genetic markers with respect to malarial resistance is discussed. Ambiguous results from population genetics quantitative methods do not support definite answers.

Blood Group Antigens↗
PubMed1984

HLA-DR in meningopolyneuritis of Garin-Bujadoux-Bannwarth: contrast to Lyme disease?

Sixteen patients with meningopolyneuritis of Garin-Bujadoux-Bannwarth (MPN-GBB) were examined for HLA-DR antigens. In contrast to data in Lyme disease (LD), which is caused by an identical or closely related spirochete, no significant association was found between the neurological disease and HLA-DR. The reported association between neurological disease and HLA-DR2 in LD may be due to the inclusion of cases with neurological disease and arthritis, since chronic arthritis in LD seems to be well correlated with HLA-DR2.

Adolescent↗
PubMed1984

Immunoglobulin allotype markers and HLA DR genes in type I diabetes mellitus.

Although it is now well established that insulin-dependent (type I) diabetes mellitus is closely associated with genes of the HLA-DR locus, the genetics of the disease remains an area of controversy. It is generally believed that the HLA-linked diabetes genes provide the majority of disease susceptibility to type I diabetes, however, there is some evidence for the existence of other non-HLA-linked genetic loci predisposing to this disorder. Therefore, allotypes of the Gm (immunoglobulin heavy chain) locus on chromosome 14 and of Km (immunoglobulin light chain) locus on chromosome 2 were studied in 180 caucasoid type I diabetic patients. No association between immunoglobulin allotype markers and the whole group of type I diabetes could be observed. However, a particular immunoglobulin allotype, G1m(a), and a particular Gm immunoglobulin phenotype (a-x-f+b+) showed a significant heterogeneity within the diabetics subdivided by HLA-DR type. The data of this study support the concept that (1) the genes in the HLA region provide the majority of, but not the only, genetic susceptibility to type I diabetes mellitus and (2) Gm-associated genes could interact with these susceptibility genes at least in the DR3+4 heterozygote type I diabetics. Further studies should be undertaken in order to elucidate a possible role of these factors in the humoral immune response of type I diabetics and their families.

Diabetes Mellitus, Type 1↗
PubMed1984

Clinical and immunologic studies of HLA-DR typed insulin-dependent diabetics--a mini-review.

There is strong association between insulin-dependent (type I) diabetes and the HLA DR3 and/or DR4 factors. Also, evidence has been accumulated that an immune response gene associated to the DR3 region may be a denominator for the development of an endocrine autoimmunity. It is particularly the late onset type I diabetes that belongs to the so-called "primary" autoimmune variety and also shows an increased tendency for the development of other autoimmune disorders. HLA DR 3 and/or HLA DR 4 associated mechanisms seem to influence a variety of clinical and immunologic findings in type I diabetes. Basically, this concept is supported by findings on seasonal variations in diabetes manifestation, on viral antibodies, on anti-insulin antibody formation, and on the natural course of endogenous insulin secretion in relation to HLA haptotypes . There are, however, conflicting data concerning islet cell antibodies, circulating immune complexes, and the incidence of diabetic microangiopathy in relation to the HLA-system. Many of these findings may be explained on the basis of an HLA heterogeneity. But this does not necessarily point to an etiological genetic heterogeneity of type I diabetes.

Adult↗
PubMed1984

HLA antigens and toxicity to gold and penicillamine in rheumatoid arthritis.

One hundred sixty-eight patients with rheumatoid arthritis treated with chloroquine (n = 87), gold salts (n = 133) and/or penicillamine (n = 77) were investigated for possible associations between HLA antigens and toxic reactions. Patients with 2 or more side effects to gold and/or penicillamine had a significantly increased frequency of antigens HLA-B8 and DR3 compared to patients with one or without adverse reactions. Proteinuria to gold or penicillamine was significantly associated with HLA-B8 (relative risk [RR] 4.2) and DR3 (RR 14.0) whereas nonnephrologic side effects to gold or penicillamine were associated with B7 and DR2 (RR 3.5 and 2.8). Patients with skin reactions to gold had a significantly greater frequency of HLA-B7. We found no correlation between chloroquine side effects and any HLA antigen. The results suggest a genetic predisposition to toxic reactions to gold or penicillamine based on an immunologic dysregulation.

Adult↗