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Biomedical subjects

H Schmidt

Publications and source records attributed to H Schmidt.

At least 739 records · Page 41Linked to original sources
PubMed1987

Determination of nucleotides, nucleosides and nucleobases in cells of different complexity by reversed-phase and ion-pair high-performance liquid chromatography.

Procedures are presented for the analysis of profiles of purine and pyridine compounds in human and rabbit red blood cells by reversed-phase high-performance liquid chromatography and in Ehrlich ascites tumour cells of mouse by ion-pair high-performance liquid chromatography. These compounds are present in rabbit erythrocytes in higher concentrations than in human blood cells, and in rabbit reticulocytes the concentration of purine compounds is still higher. During glucose-free incubation, human red cells accumulate adenosine and adenine in the presence of coformycin owing to the inhibition of adenosine and AMP deamination. Ehrlich ascites tumour cells lose major portions of purine mono-, di- and triphosphates between the seventh and eleventh day after inoculation into mouse peritoneal cavities.

Animals↗
PubMed1987

[Campylobacter pylori in the stomach, duodenum and colon of gastroenterological patients. An epidemiologic study of 120 subjects].

In a prospective study of 120 gastroenterological patients in Berlin, Germany, the prevalence of Campylobacter pylori was determined. When the gastric mucosa was normal, the prevalence was one in 19 patients (5.3%). In 101 patients with chronic gastritis it was cultured in 55 (54.5%). In 31 patients with chronic atrophic gastritis the organism was cultured in 25 (81%); in 60 patients with severe gastritis it was present in 75%, in 35 with moderate or severe chronic active gastritis in 82.8%. The diagnosis of gastric ulcer (9) or duodenal ulcer (12) was associated with the isolation of Campylobacter pylori in 55.6 and 91.7%, respectively. The prevalence of this organism in antral mucosa of this group of patients thus corresponds to that in Australia, England and North America. The organism was also demonstrated in the duodenum of 10 among 25 patients examined. But in none of 25 patients was it demonstrated in the sigmoid colon.

Berlin↗
PubMed1987

Characterization in vitro and in vivo of progressively adriamycin-resistant B16-BL6 mouse melanoma cells.

Adriamycin (ADR)-resistant sublines of B16-BL6 mouse melanoma selected by exposure to increasing concentrations of ADR were characterized in vitro for growth properties and in vivo for tumorigenicity and pulmonary metastases. The progressively resistant sublines adapted to grow in the presence of 0.025, 0.05, 0.1, and 0.25 microgram/ml ADR in monolayer culture were found to be 5-, 10-, 20-, and 40-fold ADR-resistant, respectively, compared to the parental sensitive cells, using a soft-agar colony assay and continuous ADR treatment for 7 days. The doubling time in monolayer culture of the parent sensitive and progressively ADR-resistant sublines of B16-BL6 melanoma cells was approximately 16-18 h. Although the colony-forming efficiency in soft agar of parental sensitive cells was only 0.5-4%, the 5-, 10-, 20-, and 40-fold ADR-resistant sublines had colony-forming efficiencies of 15, 20, 30, and 77%, respectively. Tumorigenicity in C57BL/6 mice of progressively ADR-resistant sublines was similar to parental sensitive cells following s.c. and i.p. implantation of 10(5)-10(6) tumor cells. Experimental pulmonary metastases were significantly lower in ADR-resistant sublines with progressive resistance. Additionally, unlike the parental sensitive and 5-fold ADR-resistant B16-BL6 cells, the 10-, 20-, and 40-fold ADR-resistant sublines were spontaneously nonmetastatic. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunochemical detection of P-glycoprotein revealed the presence of a Mr 170,000 plasma membrane glycoprotein in the 40-fold ADR-resistant subline and its counterpart maintained for 1 year in ADR-free medium. Results from this study suggest that progressively ADR-resistant B16-BL6 mouse melanoma cells selected in vitro demonstrate a marked increase in colony formation in soft agar and a decrease in the ability to produce pulmonary metastases, without alterations in tumorigenicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1987

[Echocardiography in clinically suspected chronic cor pulmonale].

UNLABELLED: In a prospective study the echocardiography (M-mode-and two dimensional methodology) as well as the electrocardiography were tested in 40 patients with chronic bronchopulmonary diseases and suspicion of chronic cor pulmonale concerning their statements about right-ventricular hypertrophy and dilatation of the right-sided cavities of the heart. RESULTS: In the question of right-ventricular hypertrophy the electrocardiography showed only a slight sensitiveness of 0.125. However, the echocardiographic criteria of the right-ventricular hypertrophy and of the dilatation of the right-sided cavities of the heart a sensitiveness of 0.809 and a specificity of 0.750. With only 3 out of 40 echocardiograms which could not be evaluated for reasons of the image quality the rate of the success of the echocardiographic investigation of 0.925 was significantly high in the group of patients who are difficult to be examined in this respect.

Cardiomegaly↗
PubMed1987

Chloroquine is a muscarinic antagonist. Binding and dose-response studies with chick embryo cells.

A muscarinic acetylcholine receptor is present on undifferentiated cells of the chick embryo. We show that, in the chick embryo, chloroquine binds to the muscarinic receptor site and behaves as a muscarinic antagonist. In competition studies performed with cell suspensions, chloroquine displaced the specific muscarinic ligand [3H]quinuclidinylbenzilate ([3H]QNB) from the receptor. The dissociation constant (KD) of chloroquine was calculated to be 6.0 X 10(-6) M. In saturation studies performed in chick embryo homogenate, chloroquine shifted the binding curve of [3H]QNB to the right (KD = 4.8 X 10(-6) M). Dose-response curves were established by measuring the acetylcholine-triggered Ca2+ mobilization in cell suspensions by means of a fluorometric assay with chlorotetracycline. Chloroquine shifted the dose-response curve to the right. The inhibitory constant (KI) of chloroquine calculated from the dose-response curve was 1.5 X 1 10(-5) M. Our observations provide an explanation for the known interference of chloroquine with the muscarinic cholinergic systems in a variety of adult organs.

Animals↗
PubMed1987

Successful bone marrow transplantation from an unrelated donor in a child with AML in second remission.

In February 1986 we transplanted a 10-year-old girl with AML in second remission with the bone marrow of an unrelated donor. HLA-types were different for one A- and one B-antigen between patient and donor. Conditioning regimen consisted of 14 Gy total body irradiation with lung shielding, 8 X 3 g/m2 cytosin arabinoside and 90 mg/kg cyclophosphamide. GVHD-prophylaxis was performed with cyclosporin A, methotrexate and prednisolone. Only mild GVHD I of the skin could be observed after rapid engraftment. 100 days after transplantation the patient was in good clinical condition and GVHD-prophylaxis was discontinued without any reactivation of acute or chronic GVHD. Engraftment was documented by sex chromosome and blood group typing. 120 days after transplantation leukemic blasts were detected in the peripheral blood and the child died 130 days after BMT from relapse of the leukemia. Despite the negative outcome, this was the first successful bone marrow transplantation from a unrelated donor in Germany.

Bone Marrow Transplantation↗
PubMed1987

Philadelphia-positive chronic myelogenous leukemia with breakpoint 5' of the breakpoint cluster region but within the bcr gene.

We report on the first Philadelphia chromosome (Ph) positive chronic myelogenous leukemia (CML) characterized by a rearrangement within the 5' part of the bcr gene on chromosome 22, but outside the restricted breakpoint cluster region. In situ hybridization studies revealed a translocation of the c-abl oncogene to the Ph chromosome and Northern blot analysis identified a chimeric 8 kb bcr/abl RNA transcript in leukemic cells. These data suggest that 1. less bcr coding sequences than previously assumed may be essential for the putative transforming activity of the rearranged bcr/abl gene and 2. the bcr probes currently used for diagnostic purposes could miss Ph-positive CML cases.

Adult↗
PubMed1987

Strains of Schizosaccharomyces pombe with a disrupted swi1 gene still show some mating-type switching.

The swi1+ gene is necessary for effective mating-type (MT) switching in Schizosaccharomyces pombe. It was cloned on a 4.2 kb genomic DNA fragment. By site-directed integration into the genome and gene disruption experiments it was proved that the swi1+ gene itself and not a suppressor had been isolated. Disruption of the swi1+ gene causes a phenotype identical to that of the original swi1 mutant, i.e. the strain still shows some MT switching. The swi1 gene is unique in the genome and gives rise to a 3 kb mRNA.

Chromosome Mapping↗
PubMed1987

Identification of a lys2 mutant of Candida maltosa by means of transformation.

We have isolated five mutants of Candida maltos, which lack the 2-aminoadipate reductase activity, an enzyme involved in the lysine biosynthesis. By means of complementation analysis using protoplast fusion, the isolated mutants were divided into two complementation groups. Thereof the C. maltosa strain G457 could be transformed by the plasmids pDP12 and pDP13, which contain the LYS2-coding gene of Saccharomyces cerevisiae. On the basis of our presented results obtained by studies on hybridization, stability, and recovery of plasmids from C. maltosa transformants, we suggest that transformation does proceed integratively.

Aldehyde Oxidoreductases↗