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Biomedical subjects

M Schmid

Publications and source records attributed to M Schmid.

At least 505 records · Page 28Linked to original sources
PubMed1985

[Familial, structural aberration of the Y chromosome with fertility disorders].

Cytogenetic studies on a patient with Klinefelter's syndrome revealed an inherited, structural aberration of the Y-chromosome which has not been described before. The aberrant Y-chromosome was characterized by eight different banding methods. The value of individual staining techniques in studies on Y-heterochromatin aberrations is emphasized. Analysis of the cytogenetic studies (banding methods, restriction endonuclease of DNA, and measurement of the length of the Y-chromosome) permits an interpretation to be made on how the aberrant Y-chromosome originated. The functions of the Y-chromosome are discussed. The decrease in fertility (cryptozoospermia) in the two brothers with the same aberrant Y-chromosome was striking.

Adolescent↗
PubMed1984

[Improvement of blood rheology by intensive physical training].

In a comparative study of athletes and sedentary normal persons, it is shown that the former have significantly better hemorheological factors. In a follow-up study, it is further shown that in healthy subjects, an intensive training programme continued for a period of three months, leads to a lowering of blood viscosity, which is comparable with the effects that can be achieved with suitable hemorheological treatment.

Adult↗
PubMed1984

[Delta superinfection of hepatitis B in Switzerland: histology and serology of 28 patients].

A series of 610 consecutive liver biopsies collected from Jan. 1980 to Oct. 1983 in two Swiss gastro-enterological centers was studied by immunohistology for the presence of delta-antigen, HBsAg and HBcAg in frozen sections. This led to the identification of 46 tissue and 45 serum samples of 28 patients, including 5 with follow-up biopsies. All had ongoing hepatitis B (HB) with delta-superinfection, representing 13.3% of all patients with HB. The sera were studied for HBsAg, anti-HBs, anti-HBc and HBe-markers by RIA, for anti-delta by indirect immunofluorescence on delta-positive test sections and for Dane particles by immune electromicroscopy. 18 of the 21 native Swiss patients were i.v. drug users between 20 and 28 years of age (30% of all drug users in this series). The other patients were residents from Mediterranean countries (n = 5), Eastern Europe (n = 1) and Asia (n = 1). Female patients (n = 5) were seen only among i.v. drug users. The most frequent histological type of HB was chronic active (aggressive) hepatitis (CAH) (26 of 46 biopsies or 13 of 28 patients, respectively), followed by acute HB with histological signs of possible transition to chronicity (8 of 46 biopsies or 6 of 28 patients), and acute lobular HB (6 of 46 biopsies or 5 of 28 patients). Chronic persistent HB (CPH) was rare (5 of 46 biopsies, final diagnosis in 3 patients). The delta-infection was found to persist in sequential biopsies when a chronic HB was established, the longest documented period being 72 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Malignant neuroleptics syndrome].

The neuroleptic malignant syndrome is clinically characterised by the presence of severe muscular rigidity, altered consciousness, hyperthermia and by signs of autonomic dysfunction. A severe form of the syndrome lasting several weeks was observed in a 20-year-old, mentally retarded female patient while under fluphenazine treatment. Cerebrospinal fluid was examined for monoamine metabolites by high-performance liquid chromatography both during the acute and the convalescent phases of the disease. Since the disease carries a considerable mortality, early diagnosis and rapid withdrawal of all neuroleptic medication is of primary importance.

Adult↗
PubMed1984

Application of a high-resolution TV-microscope system to estimate the sequence of centromere separation in muntjak chromosomes.

The sequence of centromere separation in muntjak fibroblasts was studied using a high-resolution TV-microscope system. Computer programs that identify the chromosomes as well as measure the centromere separation are described. Important prerequisites for this study are the high sampling rate and the digital processing of the two images from the red and green channel of a color TV-camera. The study demonstrates that the centromeres do not separate in a random sequence and that the separation sequence is not solely controlled by the amount of constitutive heterochromatin in the chromosomes.

Animals↗
PubMed1984

Satellited Y chromosomes: structure, origin, and clinical significance.

Three cases of inherited satellited Y chromosomes (Yqs) were analysed using several cytogenetic techniques. The cytogenetic data of the 14 cases of Yqs chromosomes described to date were reviewed. All Yqs chromosomes carry an active nucleolus organizer region (NOR) in their long arm and must have developed from translocations involving the short arms of the acrocentric autosomes. The structure of the heterochromatic satellite region in the Yqs chromosomes shows conspicuous inter-familial differences; this permits the reconstruction of the translocations from which the various Yqs were derived. Some causal factors leading to the development of Yqs chromosomes are considered: the specific localization of the four satellite DNAs and highly methylated DNA sequences in the karyotype, and some new experimental data on the spatial arrangement of heterochromatic regions in interphase nuclei. These provide distinct evidence for a preferential involvement of the autosomes 15 and 22 in the translocations with the Y heterochromatin. All clinical reports documenting Yqs males born with malformations were reviewed. It appears that the presence of an extra NOR and NOR-associated heterochromatin in the Yqs chromosomes does not cause any phenotypic abnormalities (as long as the Y euchromatin is intact). The possibility that a Yqs chromosome predisposes to non-disjunction and/or to translocations of other chromosomes is discussed.

Adolescent↗
PubMed1984

Segregation of HLA-DR2 among affected and non-affected offspring of 66 families with type 1 (insulin-dependent) diabetes.

Segregation of HLA-DR2 among affected and unaffected offspring was studied in 66 HLA-genotypes families with Type 1 diabetes in whom at least one parent carried DR2. The frequency of DR2-positive parents (21%) was not different from that of control families (29%). Among the diabetic probands, the gene frequency of DR2 was significantly decreased compared with control subjects (0.05 versus 0.17, p less than 0.001) as were DR5 (0.07 versus 0.17, p less than 0.01) and DR7 (0.06 versus 0.13, p less than 0.003). Twenty probands carried DR2, in 11 or whom (55%) it was found in combination with either DR3 or DR4. The nine cases who carried another DR allele included one who was DR2 homozygous. Transmission of DR2 was reduced in affected offspring, and random in unaffected siblings, compared with the expected ratio. However, when the DR2 transmission was analysed separately for parents bearing DR2 with DR3, DR4 or another DR allele, it appeared that DR2 transmission to affected offspring was random when the parents carried neither DR3 or DR4, the transmission deficit being due to over-transmission of DR3 and DR4. The haplotype analysis showed that the haplotype A3, Cw7, B7, GfS, DR2, found in 19% of "non-diabetic" DR2 haplotypes was practically absent among "diabetic" DR2-haplotypes (4%). In conclusion, population and segregation analysis could not demonstrate a specific protective effect of DR2.

Diabetes Mellitus, Type 1↗
PubMed1984

Genetic polymorphism of the fourth component of complement and type 1 (insulin-dependent) diabetes.

The complement proteins, Bf, C2, C4A and C4B, are closely linked to HLA. In 74 propositi and their families, and 97 controls genotyped for HLA-A, -B, -C, DR, -Bf, a high incidence of the C4BQ0 variant was detected in the patient group (33% versus 12%, p less than 0.00001); C4BQ0 was more frequent in propositi than in non-affected siblings (40 out of 74 versus 36 out of 92, p less than 0.05). When comparing the distribution of the phenotype C4BQ0 in Type 1 diabetic patients and normal control subjects, the difference was significant in patients bearing DR3 or DR4 (56% and 25%, respectively, p less than 0.003). The main linkage disequilibria were observed among the 74 propositi: B18, BfF1, C4, A3, BQ0, DR3; B12, BfS, C4, A3, BQ0, DR4. The existence of a silent allele at the C4 B locus is known to be associated with a defective immune response.

Complement C4↗
PubMed1984

5-Azacytidine-induced undercondensations in human chromosomes.

The cytosine analogue 5-azacytidine induces very distinct undercondensations in human chromosomes if applied to lymphocyte cultures. The number of induced undercondensations and their chromosomal localization can be varied by the 5-azacytidine dose and the treatment time. "Pulverized" chromosomes or undercondensations in the G-band-positive chromosome regions are produced with high doses and long treatment times. If applied in low doses during the last hours of culture, 5-azacytidine induces specific undercondensations in the heterochromatin of chromosomes 1, 9, 15, 16, and Y. Optimum conditions required for inducing the various types of undercondensation in the chromosomes were determined. Various examples of the use of 5-azacytidine in the analysis of chromosome rearrangements involving heterochromatic regions are presented.

Azacitidine↗
PubMed1984

The use of distamycin A in human lymphocyte cultures.

The effect of the oligopeptide antibiotic distamycin A on human lymphocyte cultures was examined. Distamycin A specifically inhibits the condensation of the Y heterochromatin and induces a fragile site in the chromosome 16 (band q22) in some individuals. The optimal culture conditions under which an undercondensation of the Y heterochromatin and an induction of the fragile site in 16q22 can be achieved by in vitro treatment of lymphocytes were determined. This also permits the use of distamycin A in routine diagnostics of human chromosomes. The use of this technique in the analysis of translocations involving the Y chromosome is presented. The distamycin A-DNA interaction and the different possible explanations for the distamycin A-induced undercondensations of the Y heterochromatin and fragile sites 16q22 are discussed.

Cells, Cultured↗
PubMed1984

Specific silver staining of experimentally undercondensed chromosome regions.

Treatment of human and mouse cell cultures with DNA binding AT-specific compounds and with some base analogues induced distinct undercondensations in several heterochromatic chromosome regions. All those heterochromatic regions undercondensed by AT-specific DNA ligands (distamycin A, DAPI, Hoechst 33258) could be heavily labeled with the silver(Ag)-staining technique; but the heterochromatic regions undercondensed with the cytidine analogue 5-azacytidine were Ag-negative. In metaphase chromosomes from BrdU-treated human cell cultures, the bifilarly substituted chromatids, which show a slight undercondensation, were also Ag-negative. Cytochemical analyses of the Ag-stained undercondensed heterochromatic regions showed that the Ag-stainable material consisted of nonhistone proteins. The mechanism of Ag staining in the undercondensed heterochromatic regions was compared with Ag staining of the nucleolus organizer regions.

Animals↗
PubMed1984

[Preliminary study of HLA markers in French Catalonia].

Forty-two sets of parents and their two children, who had their origins for at least three generations in French Catalonia, were studied for HLA-A,B,C,DR and Bf alleles of the Properdine complement factors. Four haplotypes were observed to be in strong linkage disequilibrium (p less than 10(-3)): A1, Cw7, B8, DR3; Aw30 (Cw5), B18, BfF1, DR3; A1 (Cw6), B17; A29 or Aw23, Cw4, B12, BfF, DR7. The observed linkage disequilibria of these haplotypes in the French Catalonian population were compared with those already described among populations from the Basque country, the Toulouse area and Spanish Catalonia.

Adult↗
PubMed1984

Monoclonal gammopathy in chronic active hepatitis.

Immunoelectrophoresis was performed in 31 of 272 patients with chronic active hepatitis (CAH) because of an M-spike component (seven patients, 2.6%) or hypergammaglobulinemia (24 patients) revealing a monoclonal gammopathy (MG) in 11 patients. In addition, 50 randomly selected patients with CAH and no evidence for an M-spike component were tested by immunoelectrophoresis. In 13 patients (26%), an MG was found. The mean age of the 24 patients with MG was 57.4 years (range: 23-76). HBsAg was present in nine patients (37.5%), no HBV-marker was detected in ten patients (41.7%). The immunoglobulin class of MG was IgG in ten patients (41.7%), IgA in one patient (4.2%) and IgM in 11 patients (45.8%). In two patients, Bence Jones protein was found in either serum or urine. In only one patient was the MG associated with multiple myeloma, whereas none of the other 23 patients developed a malignant lymphoproliferative disease within the median observation period of 6 years. We conclude that there is an unexpectedly high prevalence of benign MG in patients with CAH.

Adolescent↗
PubMed1984

Distamycin A/DAPI bands and the effects of 5-azacytidine on the chromosomes of the chimpanzee, Pan troglodytes.

The chromosomes of the chimpanzee were stained with distamycin A/DAPI, which labels specific C-bands. Bright distamycin A/DAPI fluorescence was found in the heterochromatic regions of chromosomes 6, 11, 14 to 16, 18 to 20, and 23 and the Y. Lymphocyte cultures from chimpanzees were treated with low doses of 5-azacytidine during the last hours of culture. This cytosine analog induces highly distinct undercondensations in 28 heterochromatic regions of 19 chromosomes. These 5-azacytidine-sensitive regions are predominantly located in the terminal C-bands of the chromosomes. In vitro treatment with 5-azacytidine also preserves into the metaphase stage somatic pairings between the 5-azacytidine-sensitive heterochromatic regions in interphase nuclei. The homologies and differences regarding the chromosomal localization of distamycin A/DAPI-bright C-bands, 5-azacytidine-sensitive heterochromatin, 5-methylcytosine-rich DNA sequences, and satellite DNAs in the chimpanzee and man are discussed.

Animals↗
PubMed1984

[Interferon production in acute virus hepatitis].

Serum interferon activity was measured in 40 patients with acute viral hepatitis A, B and non-A-non-B during the acute stage of the disease and correlated with the severity, the long-term outcome and the viral etiology of the disease. Patients with alcoholic hepatitis, patients with an influenza-like illness and healthy volunteers served as controls. 80% of all patients with virus hepatitis revealed no measureable or only borderline interferon activity in their serum. No correlation was found with severity and long-term outcome of the disease, but patients with virus hepatitis A showed a stronger interferon induction than patients with hepatitis B and non-A-non-B. Further investigations of the interferon system in patients with virus hepatitis might help to improve our understanding of the different forms of the disease. The data presently available, however, do not permit as yet to define the value of interferon in the treatment of severe forms of acute virus hepatitis.

Hepatitis A↗
PubMed1984

HLA-DR genotype risks in seropositive rheumatoid arthritis.

We studied the distribution of HLA-A, B, C, and -DR antigens in 77 Caucasian patients with sero-positive rheumatoid arthritis. Forty-four patients were genotyped and compared with the control panel of 110 unrelated Caucasian genotyped donors. The data obtained confirm the association of DR4 with RA, and reveal an increased risk of disease for patients carrying DR1, DR2, and DR3, compared to the risk for those carrying other antigens, such as DR5, DRw6, and DR7. There is a higher risk for DR4/4 homozygotes than for DR4/1, DR4/2, or DR4/3 heterozygotes. DR4/5, DR4/6, and DR4/7 have a lower risk than the previously mentioned genotypes. The genotype risks are compatible with the inheritance of a single, linked genetic determinant of disease susceptibility, but we are unable to distinguish between recessive and dominant inheritance of susceptibility using the "antigen-frequencies-amongst-diseases" method. DR4 seems to be more frequent in patients in whom onset occurs before the age of 35 (79% vs. 54% DR4 positive). A significant excess of DR3 + is observed in patients with toxic complications following treatment with gold salts (X2(1) = 8.96).

Adult↗
PubMed1984

[Clinical course of non-A, non-B hepatitis].

Diagnosis of seronegative hepatitis non-A-non-B today can only be established by exclusion. The infectious agent probably is of vital nature. Two or more viruses seem to occur: One of these leads to outbreaks of the disease after short incubation (2-5 weeks), the other one after long incubation (6-26 weeks). Transmission essentially occurs parenterally. The disease starts with extreme fatigue; only 20-25% of the patient will get jaundice. Usually increase of transaminases is smaller than in hepatitis B, and the clinical picture milder. In about 50% of the cases hepatitis non-A-non-B becomes chronic; tendency for complete cure, however, is greater than in hepatitis B. In chronic cases biopsy of the liver seems to be important, since in our experiences relatively typical changes of the portal fields occur. There are no general recommendations for therapy. Blood donors with increased SGPT should not be accepted.

Bile Ducts↗