Search PubMed⌕ Search

Biomedical subjects

M Schmid

Publications and source records attributed to M Schmid.

At least 397 records · Page 22Linked to original sources
PubMed1990

[Chronic hepatitis B: diagnostic value of hepatitis-B-virus DNA analysis in serum and liver tissue].

The diagnostic value of hybridization analyses for the detection of hepatitis B virus (HBV) DNA in serum and liver tissue was investigated in 79 patients with chronic liver disease. Active viral replication was demonstrated by the detection of HBeAg or HBV-DNA in serum or liver tissue. However, HBV-DNA was also detected in the absence of HBeAg in serum. No correlation was found between the presence of HBV-DNA in serum or liver tissue and clinico-chemical or histological disease. In HBsAg-negative patients no HBV-DNA was detected in serum or liver tissue. These data indicate that serological markers are sufficient for the diagnosis of HBV infection. However, detection of HBV-DNA in serum or active viral replication in liver tissue is important in selecting patients for antiviral therapy (e.g. interferon) and monitoring its efficacy.

Adolescent↗
PubMed1990

[Acute hepatitis following administration of fansidar].

Since 1971 pyrimethamine-sulfadoxine (Fansidar, Roche) has been used worldwide for prophylaxis and therapy of chloroquine resistant Plasmodium falciparum malaria. The drug monitoring team of the producing firm has received reports of a number of cutaneous adverse reactions, some severe, and a few even with fatal outcome. Liver reactions were also encountered, with severe cases only in the recent literature. We report on two patients with hepatitis in temporal relationship to pyrimethamine-sulfadoxine, the first with a second event after later exposure to the same drug. After discontinuing the medication the liver function abnormalities returned to normal limits within a few weeks. Liver biopsy and a positive lymphocyte transformation test against sulfadoxine, a component of Fansidar, strongly suggest that Fansidar was the cause of hepatic injury.

Adult↗
PubMed1990

Heterogeneities in the distribution of (GACA)n simple repeats in the karyotypes of primates and mouse.

Tandemly organized simple repetitive sequences are widespread in all eukaryotes. The organization of the simple tetrameric (GACA)n sequences at chromosomal loci has been investigated using in situ hybridization with chemically pure oligonucleotide probes. Both biotin- and digoxigenin-attached (GACA)4 probes reveal specific hybridization signals over the short arms of all acrocentric autosomes in man. In the other examined primates the NOR-bearing autosomes could be detected by in situ hybridization with (GACA)4, and a major concentration of the GACA simple repeats could be observed on the Y chromosome in the gibbon and mouse: the hybridization site in the gibbon Y chromosome coincides particularly with the silver-stainable NOR. In the past, accumulations of (GACA)n sequences were demonstrated mainly on vertebrate sex chromosomes. Therefore, the organization of GACA simple sequences is discussed in the context of their evolutionary potential accumulation and the possible linkage with the primate rDNA loci.

Animals↗
PubMed1990

Y isochromosome associated with a mosaic karyotype and inactivation of the centromere.

A patient with azoospermia and a Y isochromosome is described. The breakpoint producing this i(Y) was within the terminal short arm of the Y chromosome. Lymphocyte cultures from peripheral blood contained a high proportion of 45,X cells and cells with different Y-chromosome rearrangements. The i(Y) had either a monocentric or dicentric appearance. In dicentrics, anti-kinetochore immunofluorescence was present at both centromeres. However, this was also true for most of the functional monocentrics (pseudodicentrics). Kinetochore staining was generally positive at the site of the inactive centromeres; only a minority of the suppressed centromeres had lost their antigenic properties. Permanently growing lymphoblasts consistently showed a monocentric i(Y) with only one fluorescing kinetochore; the immunonegative Y centromere did not recover antigenicity.

Adult↗
PubMed1990

Cytogenetic and molecular analysis of a Yq isochromosome.

The dicentric Yq isochromosome of a male with azoospermia and some features of Klinefelter's syndrome was examined using cytogenetic and molecular methods. C- and R-banding of chromosomes of peripheral blood lymphocytes revealed a complex mosaic consisting of 46,X,i(Yq)/45,XO/46,XY/47,XYY/47,XY, i(Yq)/47,X,i(Yq),i(Yq) cells. EBV-transformed lymphocytes either had a 46,X,i(Yq) (90%) or a 46,X, + mar (10%) karyotype. The marker chromosome was shown to be Y-derived by in situ hybridization. C-banding, quinacrine- and DA/DAPI-staining indicated inactivation of one of the centromeres in almost all Yq isochromosomes. The use of Y chromosomal DNA sequences demonstrated that most of the Y chromosome, including its short arm, was duplicated.

Adult↗
PubMed1990

Kinetochore formation in experimentally undercondensed chromosomes.

Treatment of human and mouse cell cultures with the cytidine analogue 5-azadeoxycytidine and the AT-specific DNA ligand Hoechst 33258 dramatically inhibited condensation of the pericentromeric heterochromatin in several chromosomes. When stained with antikinetochore autoimmune sera, these experimentally undercondensed chromosomes showed kinetochores with preserved antigenicity. The undercondensed and normally condensed chromosomes share the major antigenic determinants of the kinetochore.

Animals↗
PubMed1990

4'-O-tetrahydropyranyl-doxorubicin in advanced breast cancer: a phase II study.

In a phase II study, 35 patients with advanced breast cancer were treated with 4'-O-tetrahydropyranyl-doxorubicin (THP-DXR) (70 mg/m2 i.v. on day 1); treatment was repeated every 3 weeks. Eight patients had failed prior chemotherapy for advanced disease. A total of 34 patients were evaluable for response. After a median of 10 treatment courses (range, 3-15), objective tumor response was seen in 59% (20 of 34 patients) (95% confidence limits, 42%-75%). In all, 17 partial remissions and 3 complete remissions were observed; stable disease occurred in 13 patients. The median duration of response was 42+ weeks (range, 21 - 77+ weeks). The dose-limiting side effects were leukopenia (26 patients, WHO grade III-IV) and thrombocytopenia (9 patients, WHO grade II-IV). Nausea/vomiting was experienced by 34 patients; in 18, it reached WHO grade II-III. Other treatment-related side effects included alopecia (WHO grade II-III) in 26 patients and stomatitis and diarrhea (WHO grade I-III) in 9 patients. At cumulative doses of THP-DXR of at least 700 mg/m2 (range, 700-1,050 mg/m2), no signs of congestive heart failure were observed. We conclude that THP-DXR is effective for first- and second-line chemotherapy in advanced breast cancer and that side effects are manageable.

Adult↗
PubMed1990

Correlation between T cell receptor gamma delta isotypic forms and cytotoxic activity: analysis with human T cell clones and lines.

Three biochemically distinct isotypic forms of the human T cell receptor (TcR) gamma delta structure can be expressed at the cell membrane. This unique variation in structure of TcR, which is due to C gamma gene segments utilization, prompted us to look for isotype-association functional differences. In this regard, we have developed human T cell clones or lines from normal thymus or peripheral blood from several patients. In the present report, we have selected by phenotypic, biochemical, and TcR gene rearrangement analysis representative pairs of IL2-dependent clones or lines for each TcR gamma delta isotypic form. The results showed a lack of correlation between the TcR isotypes and the ability of the cells to proliferate in response to TcR stimulation mediated through the CD3 molecular complexes. By contrast, despite the fact that all of these representative cells exhibit an NK-like activity, as measured by their ability to kill K562, the strongest lytic activity was observed with the cells having the disulfide-bonded form of the receptor. Moreover only those latter cells were able to efficiently kill the LAK-sensitive Daudi cell line.

Clone Cells↗
PubMed1990

Nucleolar transcriptional activity in mouse Sertoli cells is dependent on centromere arrangement.

Experimental evidence suggests that centromere arrangement is relevant to the expression of ribosomal genes in murine Sertoli cells. Nuclei endowed with a nucleolus inactive in rRNA synthesis presented several clusters, each containing a bunch of individual centromeres. RNA polymerase I was not cytochemically detected in the nucleolar structure, which contained only small amounts of fibrillarin. In the course of nucleolar activation, the centromeres within the separate clusters became fused into larger centromeric bodies. Synthesis of precursor rRNAs and their processing were visualized by strong nucleolar fluorescence signals using antibodies to RNA polymerase I and fibrillarin.

Animals↗
PubMed1990

Paired arrangement of nonhomologous centromeres during vertebrate spermiogenesis.

Indirect immunofluorescence staining with human anti-kinetochore antibodies was used to study the position of centromeres during vertebrate spermiogenesis. Many species of Amphibia have a low chromosome number and very large spermatids and spermatozoa. The number of kinetochore dots correlates exactly with the haploid chromosome number. This implies that kinetochore duplication occurs in the interval between meiosis I and meiosis II. The nonhomologous centromeres are arranged in tandem during the entire course of spermiogenesis and in mature spermatozoa. A higher order centromere arrangement was found in spermiogenic cells of Anura and Urodela. In mammals, immunofluorescence analysis is complicated by the extreme condensation of chromatin during spermiogenesis and the high chromosome numbers. Nevertheless, centromere-centromere associations were observed in mammalian round spermatids and sporadically in testicular spermatozoa. This indicates that pair-wise association of centromeres is a universal principle of centromere arrangement at the postmeiotic stage.

Animals↗
PubMed1990

The dystrophin gene is autosomally located on a microchromosome in chicken.

The dystrophin gene has been mapped to a pair of microchromosomes in Gallus domesticus. In situ hybridization using a pool of biotinylated human cDNA probes allowed detection of this huge single-copy sequence without having to employ isotopic labeling. The autosomal nature of the DMD gene in chicken is supported by molecular data from quantitative Southern blot analysis and is in sharp contrast to that in all eutherian mammals studied, where it is a characteristically X-linked locus. With previous data taken into consideration, these results should prove significant in understanding the evolution of sex chromosomes during speciation as well as highlighting the importance of avian microchromosomes.

Animals↗
PubMed1990

Organization of DYZ2 repetitive DNA on the human Y chromosome.

The location of the human Y-specific repetitive DNA sequence DYZ2 with HaeIII cleavage sites spaced at 2.1 kb was reexamined. Previous reports had mapped the 2000 DYZ2 copies to the very distal end of the heterochromatic Yq12 band. In the present study, a cloned DYZ2 fragment (pHY2.1) was used for Southern and slot blot analyses of male DNA as well as for nonradioactive in situ hybridization to chromosomes. DNA and metaphase preparations from 79 individuals with polymorphic or aberrant Y chromosomes were examined. DYZ2 repeats are not confined to the distal tip of Yq12, but extend through the entire heterochromatin of Yq12. In the naturally occurring length polymorphisms of Yq, the amount of DYZ2 sequence varies in proportion to the measured sizes of band Yq12. Explanations are presented for the fact that previous studies restricted the location of DYZ2 to the telomeric end of Yq12.

Blotting, Southern↗
PubMed1990

[Malignant germ cell tumor in XY gonadal dysgenesis (Swyer syndrome)].

UNLABELLED: Case of a 20-year-old patient with severe abdominal pain, right adnexal mass, positive beta-HCG titre and free fluid in the abdominal cavity, as diagnosed by ultrasound. Laparotomy resulted in a ruptured ovarian tumour (chorionic carcinoma). Despite chemotherapy, the tumour developed fulminant metastases with a follow-up of 3 months. FINAL DIAGNOSIS: Gonadal dysgenesis, XY female type (Swyer-Syndrome).

Adult↗
PubMed1990

Increased genetic risk of hypertension in glomerulonephritis?

The present study was carried out to test the hypothesis that the familial risk of hypertension is elevated in individuals with glomerulonephritis. Sixty-three parents of 39 consecutive patients below the age of 50 years who were admitted with biopsy-confirmed primary glomerulonephritis (excluding familial glomerulonephritis) were examined. Of these parents, 57% had blood pressure greater than or equal to 160/95 mmHg and/or were taking antihypertensive medication (81% of hypertensives). In 138 parents of 87 controls (age- and sex-matched patients admitted to a surgical ward for trauma), hypertension was found in 32.6% (of whom 73% were on antihypertensive medication). Age, sex ratio and body mass index were comparable in both groups of parents. A similar proportion of parents of patients with glomerulonephritis (27%) and parents of controls (25%) had already died. There was no evidence of excess cardiovascular or renal mortality in either group of parents. Urinary abnormalities were found in a similar proportion of the parents of patients with glomerulonephritis (5%) and controls (8%). Although the effects of a shared environment are not formally excluded, the data are consistent with a possible increased genetic risk of hypertension in patients with primary chronic glomerulonephritis.

Age Factors↗
PubMed1990

High total and free 1,25-dihydroxyvitamin D concentrations in serum of premature infants.

We investigated the relationship between serum total and free 1,25-dihydroxyvitamin D (1,25-OH2D) and the biochemical regulation of 1,25-OH2D production in premature infants. We measured 1,25-OH2D, vitamin D binding protein and related biochemical parameters and calculated the free 1,25-OH2D index in serum of 17 premature infants (birthweight 810-1700 g; gestational age 31-36 weeks) on two different occasions defined by body weight (Study A: 1,750-1,850 g, Study B: 2,100-2,200 g). Dietary calcium (Ca) intake was 1,5 or 2,6 mmol/kg/d, phosphorus (P) intake 1,7 mmol/kg/d and vitamin D intake 1,000 IU/d. Biochemical results were similar in infants with different Ca intakes and all were within reference ranges. Concentrations of vitamin D binding protein (Study A 0.15 +/- 0.03 g/l, Study B 0.14 +/- 0.03 g/l; means +/- SD) were lower, concentrations of 1,25 (OH)2D (Study A 180 +/- 67 pmol/l, Study B 216 +/- 53 pmol/l) were higher, and consequently the free 1,25-OH2D index (Study A 6.6 +/- 2.7, Study B 8.8 +/- 2.6) was 4 to 6 times higher than in previously studied term infants. 1,25-OH2D and the free 1,25-OH2D index increased significantly with age and were not correlated with serum P or parathyroid hormone. The data indicate that in premature infants with normal biochemical parameters of Ca and P metabolism elevated concentrations of 1,25-OH2D signify an increased fraction of free 1,25-OH2D and that increased production of 1,25-OH2D is not due to hypophosphatemia or hyperparathyroidism.

Calcitriol↗
PubMed1990

Immunocytogenetics. IV. Human autoantibodies to heterochromatin-associated proteins.

We report here a novel class of human autoantibodies with immunological affinity for constitutive heterochromatin. Indirect immunofluorescence localized different proteinaceous antigens to the AT-rich paracentromeric heterochromatin of mouse chromosomes, the GC-rich heterochromatic regions of sheep chromosomes, and the large C-banded regions of human chromosomes 1, 9, and 16. Minor amounts of the heterochromatin-associated proteins were uniformly distributed on the chromosomes of all vertebrate species. Their antigenic determinants have been highly conserved during evolution. The chromosomal distribution of the heterochromatin-associated antigens is not altered in interspecific somatic cell hybrids but apparently reflects a stable structural property germane to each chromosome type. The antigenic proteins remain bound to their respective epitopes throughout the entire cell cycle and in meiosis. The heterochromatin-associated antigens represent a major nonhistone component of the mitotic chromosome scaffold and the interphase nuclear matrix. Immunoblotting performed with a human autoimmune serum to mouse heterochromatin revealed a characteristic pattern of polypeptides with molecular weights ranging from 35 to 120 kDal. Drugs that interfere in vivo with the higher-order chromatin structure had no effect on the expression and chromosomal distribution of the heterochromatin-associated antigens. However, the antibody binding sites in chromatin can be completely masked by treating fixed cell preparations with certain DNA-binding ligands.

Animals↗
PubMed1990

Immunocytogenetics. V. A highly conserved NOR antigen (He) is facultatively associated with nucleolar or nucleoplasmic granules.

A new protein antigen of the nucleolus organizer region (NOR), designated He, was recognized by human autoantibodies obtained from a patient with Raynaud phenomenon. In mitotic cells of all vertebrate species tested. He serum selectively immunostained the chromosomal NORs. A completely unexpected characteristic of the He antigen was its location during interphase. In mammalian cell substrates, it was concentrated in numerous nucleoplasmic granules, with minor amounts of the antigen uniformly distributed throughout the entire nucleus. In interphase nuclei of lower vertebrate cells, however, the antigen was preferentially located in the nucleolus. The antigenicity of He is not dependent on RNA or DNA; its cytochemical properties operationally classify it as a nonhistone component of the chromosome scaffold. The He antigen was present in the residual nucleolar structures of cells that were not at all active in rRNA synthesis, such as mammalian late spermatids and amphibian erythrocytes.

Animals↗