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Biomedical subjects

M Schmid

Publications and source records attributed to M Schmid.

At least 577 records · Page 32Linked to original sources
PubMed1981

Somatic pairings of the Y heterochromatin in human XYY and XYqi cells.

In human interphase nuclei containing Yq isochromosomes or two Y chromosomes, there are conspicuous somatic pairings between the brightly fluorescing Y-heterochromatin regions. These somatic pairings cannot be demonstrated in metaphases from conventional cell cultures because they are disrupted at the mitotic prophase. However, in lymphocytes cultivated in a medium containing distamycin A, the somatic pairing between Y-heterochromatin is preserved to metaphase. The present findings are compared with earlier observations of somatically paired heterochromatin. An explanation for the highly disparate frequency of somatic pairing between the Y-heterochromatin regions in Yq isochromosomes and YY chromosomes is proposed.

Chromosome Aberrations↗
PubMed1981

H-Y antigen as a tool for the determination of the heterogametic sex in Amphibia.

H-Y antigen was investigated in three amphibian species with different degrees of sex-chromosome differentiation: Bufo bufo, Triturus vulgaris, and Pyxicephalus adspersus. No heteromorphic sex chromosomes were found in B. bufo, but an examination of the progeny of hermaphrodites (Ponse, 1942) indicated that the female of this species was heterogametic (ZW). Sex chromosomes differing only by a very small heterochromatic region at their telomeres were found in the male of T. vulgaris (XY). Pyxicephalus adspersus revealed high differentiated ZW sex chromosomes. The results of the H-Y antigen studies on these three species indicate that H-Y antigen is expressed only in the heterogametic sex, irrespective of differences in morphological differentiation of the sex chromosomes. Therefore, H-Y antigen could be a valuable tool in determining the heterogametic sex, not only in Amphibia but possibly also in other vertebrate species that have either evolved no heteromorphic sex chromosomes or where sex-reversal experiments are not possible.

Amphibians↗
PubMed1981

The effects of distamycin A on gorilla-, chimpanzee- and orangutan lymphocyte cultures.

Lymphocyte cultures from the gorilla, chimpanzee, and orangutan were treated with the oligopeptide antibiotic distamycin A. This AT-specific DNA-ligand induces a distinct undercondensation in the quinacrine-bright heterochromatin of the gorilla and chimpanzee. This is also the case in human lymphocyte cultures. Distamycin A further causes an undercondensation in the nonheterochromatic bands 17q21 of the gorilla and 16q22 of man. No visible distamycin A-sensitive chromosome regions are determined in the orangutan. The in vitro treatment with distamycin A preserves the somatic pairings between the quinacrine-bright heterochromatic regions existing in the interphase nucleus until the succeeding metaphase stage. The phylogenetic origin of the quinacrine-bright and distamycin A-sensitive heterochromatin in the ancestor of man, the gorilla, and the chimpanzee is discussed.

Animals↗
PubMed1981

Diagnostic value of the fecal chymotrypsin test in pancreatic insufficiency, particularly chronic pancreatitis: correlation with the pancreozymin-secretin test, fecal fat excretion and final clinical diagnosis.

The diagnostic value of the fecal chymotrypsin test (FCT) was reevaluated with regard to (a) proved pancreatic hypofunction of different severity (183 pancreozymin-secretin tests); (b) the final clinical diagnosis, and (c) fecal fat excretion (208 patients with chronic pancreatitis; CP). Progressive pancreatic disease (cancer, CP) was mainly associated with moderate or severe pancreatic hypofunction (119/138; 86.2%) and a low incidence of false-normal FCT values (14/138; 10.1%). Miscellaneous disorders (mainly reversible pancreatic hypofunction) were mainly associated with slight pancreatic hypofunction and a high incidence of false-normal FCT values (17/45; 37.8%). Pancreatic steatorrhea (greater than 10 g/day) was found only in patients with markedly depressed FCT values. Progressive deterioration of pancreatic function was demonstrated by repeated FCT in CP (n = 220).

Celiac Disease↗
PubMed1981

[Contraceptives and the liver].

Among the typical complications of oral contraceptive use are intrahepatic cholestasis, occurring in women with a special and probably genetical predisposition only, and a thrombotic diathesis secondary to increased hepatocellular synthesis of coagulation factors, both effects induced by the estrogens. This state of hypercoagulability may lead to thrombosis of the hepatic veins and may thus cause the Budd-Chiari syndrome. A tendency to gallstone formation is explained by a derangement in the synthesis of bile acids and by changes in the permeability of liver cell membranes and of epithelial cells of the gallbladder, an effect again due to the estrogen component of the contraceptives. After long-term use, an increased incidence of benign liver cell adenomas is observed; malignant liver tumors do occur very rarely. A causal relationship with focal nodular hyperplasia, however, is unlikely. Only the typical vascular changes of this entity are probably due to the effects of the contraceptives.

Adenoma↗
PubMed1980

[Therapy of chronic hepatitis].

Treatment with glucocorticosteroids alone or in combination with azathioprine can be considered the most successful therapy in "chronic active hepatitis" of the "autoimmune" type. Immunosuppressive treatment of HBs+ chronic active hepatitis remains controversial and should be confined exclusively to severe cases. Caution is even more indicated in chronic active hepatitis of the non-A-non-B type. Antiviral therapy in chronic active hepatitis is still controverted. Relatively little experience has been gained of the enormously expensive interferon treatment.

Adrenal Cortex Hormones↗
PubMed1980

[Iodine deficiency is still endemic in Switzerland].

To obtain information on the present state of iodine supply in Switzerland random urine samples have been collected from 770 individuals for the purpose of measuring iodine and creatinine excretion. As a first step the widely used method of measuring iodine concentration per gram creatinine in casual urine samples was validated by quantitatively collecting urines for 6 consecutive 4 h periods in 11 healthy volunteers. True ioduria could thereby be compared with that calculated from random samples. 83% of all values were found to be within +/- 30% of the true mean value. The mean iodine content of all 770 samples collected in the field study was 93.3 microgram per gram creatinine (I/Cr). This mean value is slightly below the adequate iodine supply. Of even more concern is the fact that less than 60 microgram I/g Cr was found in 20% of all samples. Therefore, in the population sample as a whole the mean ioduria is still clearly below that indicating a sufficient iodine supply, and in one out of five individuals iodine excretion was typical of marked iodine deficiency. Low ioduria correlated significantly with low natriuria in both male and female subjects. This finding indicates that iodized table salt is an important though inadequate source of alimentary iodine. The increase in iodine admixture to table salt already agreed upon appears to be an appropriate means of improving nutritional iodine availability. Iodine deficiency may still be an important cofactor in the high prevalence of goiter in Switzerland. The long established goiter prophylaxis by iodine admixture to table salt may have lost part of its efficiency due to the sharp decrease in per capita consumption of salt.

Creatinine↗
PubMed1980

HLA genotype studies in juvenile insulin-dependent diabetes.

HLA genotypes were ascertained in 53 French Caucasian families, comprising 68 juvenile onset insulin-dependent diabetic siblings. Among the 49 alleles detected at different loci in the HLA complex (A, C, B, Bf, DR) 4 appeared to occur at a significantly higher frequency among the 53 index cases than in a control series of 116 healthy individuals: HLA-B18 (p < 10(-3)), DRw3, DRw4 and BfF1 (p < 10(-6)). The excess of HLA identical affected siblings confirms genotype disequilibrium and supports the hypothesis of an HLA-linked gene(s) conferring susceptibility. There was no increase of homozygosity for HLA DRw3 and DRw4 whereas there was a marked excess heterozygosity for HLA DRw3/DRw4 in diabetic patients (32% versus 0% in the control series, p < 0.001). These data provide evidence for the existence of two cooperating genes, linked to each of the HLA DR alleles.

Alleles↗
PubMed1980

Chromosome banding in amphibia. IV. Differentiation of GC- and AT-rich chromosome regions in Anura.

The chromosomes of 26 species of Anura from variously highly envolved groups were analysed with the fluorescent GC-specific antibiotics mithramycin and chromomycin A3 as well as with the AT-specific quinacrine. The mithramycin- and chromomycin A3-stainings generally resulted in a pattern of the constitutive heterochromatin opposite to the one obtained with quinacrine stain. The weaker a heterochromatic region fluoresces with quinacrine, the stronger is the intensity of the fluorescence achieved with mithramycin and chromomycin A3. Some of the telomeric and interstitial heterochromatic regions, however, exhibit no enhanced fluorescence with any of the fluorochromes. The nucleolar constrictions of the nucleolus organizer regions (NORs) displayed the brightest mithramycin- and chromomycin A3-fluorescence in the karyotypes and interphase nuclei of all species examined. The contrast of the brightly fluorescing GC-rich heterochromatin and of the NORs is considerably enhanced, when the non-fluorescent AT-specific oligopeptide distamycin A is employed as a counterstain. No banding patterns were observed with the fluorochromes in the euchromatic regions of the metaphase chromosomes; this attributed to the strong spiralization of the anuran chromosomes. A cytochemical classification of the various chromatin types in the anuran chromosomes is discussed on the basis of the differential labelings found on the constitutive heterochromatin by means of the fluorochromes.

Amphibians↗
PubMed1980

Demonstration of a heritable fragile site in human chromosome 16 with distamycin A.

Fragile sites are induced in chromosome 16 (band q22) of lymphocytes from some individuals, when the lymphocyte cultures are treated with the oligopeptide antibiotic distamycin A. These induced fragile sites are inherited in a Mendelian fashion; there are interfamilial differences in their appearance. The interactions between distamycin A and chromosomal DNA and the possible composition of the DNA at the induced fragile sites are discussed.

Chromosome Aberrations↗
PubMed1980

[Management of liver cell adenoma and focal nodular hyperplasia].

Since 1975 six cases with hepatic adenoma (5 females, 1 male) and five cases with focal nodular hyperplasia (3 females, 2 males) have been treated at our hospital. Four of the five women with hepatic adenoma took oral contraceptive pills before the diagnosis was made, only one patient took the pills in the group with focal nodular hyperplasia. Hepatic adenomas were resected electively in three patients; one patient underwent operation because of ruptureed adenoma with intraabdominal hemorrhage. In the other two cases with hepatic adenoma resections were not possible, but both tumors have regressed after the cessation of oral contraceptives. One patient in the group with focal nodular hyperplasia underwent liver resection because of intratumoral hemorrhage with recurrent pain; in the other four cases no treatment was done as symptoms were absent. We recommend elective resection for hepatic adenoma because of the high risk of spontaneous ruptur. Embolization or ligation of the hepatic artery are alternative procedures when resection is not possible and tumors do not regress after the cessation of oral contraceptives. On the other hand a more conservative attitude is suggested for focal nodular hyperplasia because those patients do not frequently bleed; resection is indicated in case of symptoms or growth of tumor.

Adult↗