Search PubMed⌕ Search

Biomedical subjects

D Schindler

Publications and source records attributed to D Schindler.

At least 91 records · Page 5Linked to original sources
PubMed1986

Pulmonary embolism after short-term treatment of acne vulgaris with ovulation suppressor agents.

A case of recurrent pulmonary embolism with infarction is described. The patient, a 28-year-old woman, had been treated over a four-month period with a preparation of cyproterone acetate plus ethinyloestradiol for acne vulgaris. It is suggested that the use of oral contraceptive preparations for the treatment of innocent disorders should be avoided when factors that may potentiate a thrombogenic effect are present.

Acne Vulgaris↗
PubMed1986

Structure, origin and effects of a supernumerary marker chromosome 15.

A de novo supernumerary small marker chromosome 15 was observed in a female infant with mental and statomotoric retardation as well as minor facial dysmorphia. The marker chromosome was analyzed by ten different staining techniques and 5-azacytidine treatment of lymphocyte cultures. It is shown that the supernumerary chromosome was derived by a non-sister chromatid exchange between the two homologous maternal chromosomes 15. The cytogenetical properties of the marker chromosome, the different activity of its two nucleolus organizer regions and the somatic pairing configurations revealed by 5-azacyidine are reported.

Child, Preschool↗
PubMed1986

Changing pattern of lung tuberculosis.

In 46 (20%) of 233 consecutive patients with active lung tuberculosis, the localization of the tuberculous process was unusual. The majority of patients (81%) were greater than 40 years of age. Men predominated in the usual localized tuberculosis group, whereas women predominated in the group with unusual localized tuberculosis (UNLT). The most common site of tuberculosis in the UNLT group was the anterior segment of the upper lobe or the middle lobe. In 17.5% of the patients in the UNLT group, the diagnosis was established by thoracotomy only. In patients with "protracted pneumonia," or chest X-ray suggestive of neoplastic disease, tuberculosis should be included in the differential diagnosis, irrespective of the site of the lesion.

Adolescent↗
PubMed1985

BrdU-Hoechst flow cytometry reveals regulation of human lymphocyte growth by donor-age-related growth fraction and transition rate.

An improved BrdU-Hoechst flow assay was applied to cell kinetic studies of human lymphocyte cultures during a 24-96 hr interval after PHA stimulation. The assay shows that the duration of the initial lag phase and the proportions of noncycling cells increase as a function of donor age, whereas the rates of transition from each cell cycle compartment to the next decrease. Cell cycle arrest occurs in the first S and G2 phase after stimulation of lymphocytes from a 75-year-old donor but not from younger donors. The data are consistent with several models of cell cycle kinetics, so long as these models are modified to include a fraction of noncycling cells in each cell cycle compartment.

Aging↗
PubMed1985

Recurrent mutation pressure does not explain the prevalence of the marker (X) syndrome.

In order to test the hypothesis that the high prevalence of the mar(X) syndrome is caused by a high mutation rate in male germ cells only, the fraction of new mutants among mothers of probands in 112 informative families has been examined by segregation analysis among their brothers and sisters. The estimated fraction of new mutants among these mothers is much lower than expected if a stable equilibrium existed between an unusually high mutation rate and a selective disadvantage of mentally retarded, male and female mar(X) carriers. Hence, the above-mentioned hypothesis could not be confirmed.

Female↗
PubMed1985

[Are there genetic risk factors in the occurrence of choriocarcinoma?].

Now that we know about the genetic production mechanisms of diseases of the trophoblast, interest is concentrated on the question which risk factors can produce a disposition in the patient - seen from a clinico-genetic angle - towards malignancy of a complete mole. Many years before the genetic interrelations became known, there had been discussions on blood relationship as a possible aetiological factor in the production of chorionic carcinoma. Since consanguinity in preceding generations can lead to a selection of certain genotypes, this question was reexamined on a limited patients material (10 patients with chorionic carcinoma and 11 with mole). The negative result of this study contradicts - similar to other recent publications on this subject - the hitherto frequently advanced hypothesis that homozygotism is responsible, for a recessive "onko" gen, for rendering a complete mole malignant. Recent investigations, for example, point to a close correlation between the presence of a Y chromosome in a complete mole, and malignancy.

Choriocarcinoma↗
PubMed1985

Cell cycle kinetics by BrdU-Hoechst flow cytometry: an alternative to the differential metaphase labelling technique.

Human lymphocyte cell cycle kinetics was studied in parallel in whole blood and in isolated lymphocyte cultures by differential metaphase labelling and by flow cytometry, employing the principle of quenching of Hoechst fluorescence by BrdU substituted DNA. The BrdU-Hoechst flow technique yields information on the kinetics of cell recruitment and cell cycle progression superior to the differential metaphase staining, since it provides data from interphase cells, including cycle compartment durations, non-cycling cell fractions and transition probabilities. The Smith and Martin model, modified to include a fraction of non-cycling cells, yields excellent correspondence to the experimental data. We show that lymphocytes isolated from Ficoll gradients respond to PHA stimulation with a 4-6 hr delay compared to whole blood cultures or to cultures with autologous serum supplementation. A detailed study of the effects of such culture supplements on lag phase duration, cell cycle compartment length, non-cycling cell fractions and transition probabilities illustrates the application and reproducibility of the flow assay. The potential of the method is further documented with two examples showing the dependence of lymphocyte proliferation on donor age and donor genotype.

Adult↗
PubMed1985

Endogenous blockage and delay of the chromosome cycle despite normal recruitment and growth phase explain poor proliferation and frequent edomitosis in Fanconi anemia cells.

BrdU-Hoechst flow cytometry was employed to study the proliferation kinetics of blood lymphocytes from patients with Fanconi anemia (FA). Compared to controls, untreated FA lymphocytes show normal response to PHA stimulation, normal G0/G1 exit rates, and normal first S-phase durations. The G2 phase of the first cell cycle, however, is severely prolonged, and 24% of the recruited population become arrested during the first chromosome cycle (S, G2/M phases). The delay suffered during G2 appears to be compensated in part by a subsequent G1 phase duration that is unusually short for postnatal human cells (3.7 +/- 0.5 hrs). In analogy to what has been observed in other cell systems after experimental delays of the chromosome cycle, we therefore postulate that at least some FA cells enter their second growth phase without prior completion of the delayed chromosome cycle. Renewed replication would ensue in such cells without prior passing through mitosis and cytokinesis, leading to endoreduplication, which is a frequent finding in the FA syndrome.

Adolescent↗
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↗
PubMed1981

Retroregulation of the int gene of bacteriophage lambda: control of translation completion.

Bacteriophage lambda regulates the integration--excision reaction as a crucial aspect of the choice of pathway during lysogenic or lytic viral development. This control involves differential expression of the tightly linked, partially overlapping int and xis genes from two promoter sites: pI, positively regulated by cII/cIII proteins, and pL, positively regulated by N protein. After lambda infection, Int is synthesized from the pI transcript under cII regulation; however, very little Int is produced from the pL RNA because of the existence of a cis-acting regulatory element, sib, on the opposite side of the int gene from the pL promoter. Presumably sib serves to prevent unwanted synthesis of Int protein during the lytic response; the Int protein necessary for excisive recombination from a prophage can be supplied by pL transcription because sib is separated from int by prophage insertion. We have studied the effect of sib on nearby lambda genes by means of gel electrophoresis of labeled proteins from infected cells. Deletion of the sib region greatly enhances production of Int protein without substantial effect on Xis production; thus, sib regulation normally is highly specific for Int. When the sib region is moved past int and xis by deletion, regulation of the adjacent gene for the protein Ea22 occurs, suggesting that sib regulation can work on other genes. Although synthesis of wild-type Int is severely inhibited by sib, shorter Int protein fragments generated by nonsense mutations escape sib regulation, indicating that the regulation is translational and occurs near the completion stage of protein synthesis. Regulation by sib thus exhibits novel regulatory features: distal location, recombinational control, and regulation of the completion of protein synthesis. Because Int and Ea22 control is lost in a RNase III- host, we suggest that sib regulation might involve RNase III cleavage of a RNA duplex region that includes sib and the regulatory target (normally the int gene). We note such a potential site within int.

Bacteriophage lambda↗
PubMed1980

Tests of bile-acid and vitamin B12 metabolism in ileal Crohn's disease.

The bile-acid breath test, fecal analysis of labeled bile acids, and Schilling test were used to study bile-acid and vitamin B12 metabolism in 31 patients with ileal Crohn's disease. Results of the bile-acid breath test were positive for 42% of the patients; Schilling test, 42%; fecal analysis of bile-acid labels, 19%. Combination of the tests increased the percentage of positive cases to 65. About 50% of the patients who had positive breath tests had evidence of normal bile-acid absorption, indicating increased bile-acid deconjugation by small-intestinal bacteria. The other 50% had evidence of various degrees of bile-acid malabsorption. Disease activity did not correlate with results of any test. Extent of ileal involvement correlated with results of the bile-acid tests, but not with those of the Schilling test. The study demonstrates that there is a wide spectrum of disturbances of bile-acid and vitamin B12 metabolism in ileitis, and that the tests should be useful in the diagnostic evaluation of patients with proven or questionable Crohn's disease who have diarrhea and malabsorptive abnormalities that could be related to disturbances of bile-acid and vitamin B12 metabolism.

Adolescent↗
PubMed1979

Sensitivity of bile acid breath test in the diagnosis of bacterial overgrowth in the small intestine with and without the stagnant (blind) loop syndrome.

The bile acid breath test was studied to examine its sensitivity for establishing the diagnosis of bacterial overgrowth in comparison to that of the Schilling test and small-intestinal cultures in 12 patients with a stagnant (blind) loop syndrome, as well as in 38 patients who had other conditions with suspected bacterial contamination of the small intestine. The presence of bile acid malabsorption was excluded in all 50 patients by studies of fecal excretion of radioactively labeled bile acids. The bile acid breath test was positive in 100% (12/12) of the patients with a stagnant (blind) loop syndrome, whereas 92% (11/12) had a positive Schilling test and 75% (9/12) a positive small-intestinal culture. The abnormal tests improved only in 2 of 4 patients treated with tetracycline. In the group of 38 patients without demonstrable dilated or blind loops of small bowel who were suspected of having bacterial contamination of small bowel, the bile acid breath test was positive in 53% (20/38), the Schilling test in 39% (15/38), and the small-intestinal culture in 45% (17/38). The difference in the incidence of positive results between the tests in the two patient groups was statistically not significant. The findings of these studies have the following diagnostic implications: (1) Bile acid breath test, Schilling test, and cultures of aspirates from the upper small bowel are of comparable sensitivity in the detection of bacterial overgrowth in the small intestine. (2) A negative bile acid breath test makes the diagnosis of a stagnant (blind) loop syndrome very unlikely.

Bacteria↗
PubMed1978

Studies on the mode of action of hygromycin B, an inhibitor of translocation in eukaryotes.

Hygromycin B is an unusual aminoglycoside antibiotic active against both prokaryotic and eukaryotic cells. Hygromycin B at 0.38 mM concentration completely halts yeast cell growth in rich media, presumably by preventing protein synthesis by cytoplasmic ribosomes. Polypeptide synthesis in cell-free extracts from rabbit reticulocytes, wheat germ and yeast is strongly blocked by low concentrations of hygromycin B. The antibiotic inhibits peptide chain elongation by yeast polysomes by preventing elongation factor EF-2-dependent translocation, although it does not affect either the formation of the EF-2-GTP-ribosome complex or the EF-2- and ribosome-dependent GTP hydrolysis which takes place uncoupled from translocation. The inhibition of translocation by hygromycin B might result from the stabilization of peptidyl-tRNA bound to the ribosomal acceptor site, since the stability of [3H]Phe-tRNA-EF-1-poly(U)-ribosome and [3H]Phe-tRNA-poly(U)-ribosome complexes is increased in the presence of hygromycin B. The inhibition of polyphenylalanine synthesis by reticulocyte ribosomes and enzymic translocation of peptidyl-tRNA by yeast polysomes can be reversed by increasing concentrations of EF-2 suggesting a relationship between the binding sites of EF-2 and hygromycin B on the ribosome. Neither non-enzymic translocation, that takes place in the presence of high potassium concentrations, nor the peptide bondforming step are affected by hygromycin B.

Animals↗
PubMed1977

[Hyperoxaluria in intestinal and liver diseases].

Excretion of oxalic acid in urine was measured in 28 healthy and 97 patients with gastrointestinal diseases. We found significantly higher values in the following groups: patients after resection of parts of the small intestine, patients with sprue and other diseases with malabsorption, patients with M. Crohn of the small intestine, colitis ulcerosa and granulomatosa, patients with chronical diseases of the pancreas gland and patients with cirrhosis of the liver. In 4 patients after resection of parts of the small intestine or pancreas urolithiasis could be verified. Reduction of fat and food without ballast reduced the excretion of oxalic acid in urine. Hyperoxaluria correlied significantly with the following parameters: excretion of fat in feces, exhalation of 14CO2 in the glykocholate breath test, resorption of vit. B12 and the length of resected small intestine. This form of hyperoxaluria is caused by hyperresorption of oxalic acid from food. The mechanism of this hyperresorption is not clarified yet, an important factor seems to be ill resorption of fat.

Amino Acids↗