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Biomedical subjects

H Schmidt

Publications and source records attributed to H Schmidt.

At least 19 recordsLinked to original sources
PubMed1992

The protein sequence and some intron positions are conserved between the switching gene swi10 of Schizosaccharomyces pombe and the human excision repair gene ERCC1.

The switching gene swi10+ has a function in mating-type switching as well as in the repair of radiation damages. We have cloned the genomic swi10+ gene by functional complementation of the switching defect of the swi10-154 mutant. The swi10+ gene is not essential for viability. The DNA sequence revealed an open reading frame of 759 nucleotides interrupted by three introns of 127, 52 and 60 bp, respectively. The positions of intron I as well as of intron III of swi10 are evolutionary conserved in comparison to the introns III and IV of the human ERCC1 gene. The analysis of cDNA clones isolated by PCR amplification confirmed the structure of the swi10 gene. The putative Swi10 protein has homologies to the human and mouse ERCC1 protein, to Rad10 of Saccharomyces cerevisiae and to parts of UvrA and UvrC of E. coli. All these proteins are essential components for excision repair of damaged DNA. The Swi10 protein contains a putative DNA binding domain previously found in other proteins. Northern blot experiments and the analyses of cDNA clones indicate that intron I of the swi10 gene is not efficiently spliced.

Amino Acid Sequence↗
PubMed1992

Modulation of the glucagon-dependent activation of the phosphoenolpyruvate carboxykinase gene by oxygen in rat hepatocyte cultures. Evidence for a heme protein as oxygen sensor.

The glucagon-dependent activation of the phosphoenolpyruvate carboxykinase (PCK) gene is modulated by oxygen. It was proposed that heme proteins might function as O2 sensors; their actions are impaired after replacement of the central Fe2+ ion by Co2+ and inhibition of heme synthesis by succinylacetone (SA). Therefore, the effects of CoCl2 and SA, alone and in combination, on the glucagon-dependent induction of PCK activity and PCK mRNA were investigated at different physiological oxygen tensions in primary rat hepatocyte cultures. The cells were exposed to 50 microM CoCl2 and/or 2 mM SA from 4-24 h. After addition of fresh media without CoCl2 or SA, PCK was induced with 1 nM glucagon. PCK activity and PCK mRNA were elevated to 100% at 16% O2 and to about 65% at 8% O2. CoCl2 reduced these increases to about 45% at 16% O2 and to about 35% at 8% O2. SA lowered the inductions to about 50% and 40% each at 16% and 8% O2. CoCl2 plus SA diminished the elevations to about 5% at both oxygen tensions. In the presence of CoCl2 and/or SA, ornithine decarboxylase induction by insulin was not impaired; lactate dehydrogenase did not leak from the cells, which in electron microscopical inspections had normal cell structures. These findings support the hypothesis that a heme protein is involved in the activation of the PCK gene and that it acts as an O2 sensor.

Animals↗
PubMed1992

[Digital luminescence radiography in the framework of ERCP. Initial results in comparison to conventional radiography].

Forty-seven patients submitted to an ERCP were submitted, in one and the same session, to radiological examination with both conventional and digital luminescence radiography (DLR). Within the framework of this orientational study, DLR provided at least the same amount of information as the conventional examination, but was also associated with diagnostic advantages in particular in the region of the intrahepatic bile ducts and in the representation of a cholelithiasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1992

Balancing of energy-consuming processes of K 562 cells.

A balance of ATP-consuming processes in human erythroleukemia (K 562) cells by use of the decreased 14CO2 formation from [1-14C]-glutamate following inhibition of energy-requiring processes is presented. This method was tested on Ehrlich mouse ascites tumour cells and was used in suspensions of K 562 cells with a low cell content. More than 90 percent of the ATP produced by oxidative phosphorylation could be accounted for in K 562 cells. Protein synthesis consumed about 35 percent, Na+/K(+)-ATPase about 20 percent and transcription processes 5-10 percent of the total ATP. The share of the Ca(2+)-dependent reactions was notably high at 25 percent in comparison with Ehrlich mouse ascites tumour cells, reticulocytes or hepatocytes. ATP consumption by DNA synthesis was assessed at 5-10 percent. Only less than 10 percent of the consumption of ATP produced oxidatively remained for other cellular reactions. The degree of coupling of K 562 cells was high in comparison with that of other eukaryotic cell types.

Adenosine Triphosphate↗
PubMed1992

Effects of Ca2+ and other divalent cations on K(+)-evoked force production of slow muscle fibers from Rana esculenta and Rana pipiens.

Slow muscle fibers were dissected from cruralis muscles of Rana esculenta and Rana pipiens. Isometric contractures were evoked by application of K(+)-rich Ringer's containing Ca2+, Ni2+, Co2+, Mn2+ or Mg2+. High (7.2 mmol/liter) external Ca2+ concentration raised, 0 Ca2+ lowered the K+ threshold. Replacing Ca2+ by Ni2+ or Co2+ had an effect similar to that of high Ca2+ Ringer's. In Mg2+ Ringer's the K+ concentration-response curve was flattened. These effects were observed already after short exposure times in both species of slow fibers. When Ca2+ was removed for long periods of time the slow fibers of R. esculenta lost their contractile response to application of high K+ concentrations much more quickly than those of R. pipiens, while the response to caffeine (20 mmol/liter) was maintained. Upon read-mission of Ca2+ contractile ability was quickly restored in the slow fibers of both R. esculenta and R. pipiens, but the effects of Ni2+ (or Co2+, Mn2+ and Mg2+) were much larger in R. esculenta than in R. pipiens slow fibers. It is concluded that divalent cations have two different sites of action in slow muscle fibers. K+ threshold seems to be affected through binding to sites at the membrane surface; these sites bind Ni2+ and Co2+ more firmly than Ca2+. The second site is presumably the voltage sensor in the transverse tubular membrane, which controls force production, and where Ca2+ is the most effective species of the divalent cations examined.

Animals↗
PubMed1992

The switching gene swi6 affects recombination and gene expression in the mating-type region of Schizosaccharomyces pombe.

The products of 11 switching (swi) genes are required for efficient mating-type (MT) switching in homothallic (h90) strains of Schizosaccharomyces pombe. The MT region of h90 comprises three cassette genes: the expression site mat1:1 and two silent loci, mat2:2 and mat3:3. Besides reducing MT switching, the swi6 mutation leads to deletions in the MT region caused by intrachromosomal cross-overs between two paired cassettes. These deletions only arise if DNA double-strand breaks are present at mat1:1, which initiate MT switching. Furthermore, swi6 allows meiotic recombination in the K region, a region of 16 kb between mat2:2 and mat3:3; in wild-type strains no recombination occurs in K. swi6 also allows the simultaneous expression of two different cassettes in the same haploid cell. Thus swi6 may have an influence on the general chromatin structure in the MT region.

Blotting, Southern↗
PubMed1992

Characterization of a novel enzyme, N6-acetyl-L-lysine: 2-oxoglutarate aminotransferase, which catalyses the second step of lysine catabolism in Candida maltosa.

A novel aminotransferase catalyzing the second step of lysine catabolism, the oxidative transamination of the alpha-group of N6-acetyllysine, was identified and characterized in the yeast Candida maltosa. The enzyme was strongly induced in cells grown on L-lysine as sole carbon source. Its activity was specific for both N6-acetyllysine and 2-oxoglutarate. The Km values were 14 mM for the donor, 4 mM for the acceptor and 1.7 microM for pyridoxal-5-phosphate. The enzyme had a maximum activity at pH 8.1 and 32 degrees C. Its molecular mass estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis was 55 kDa. Since the native molecular mass determined by gel filtration was 120 kDa, the enzyme is probably a homodimer.

Candida↗
PubMed1992

Treatment of fish parasites. 9. Effects of a medicated food containing malachite green on Ichthyophthirius multifiliis Fouquet, 1876 (Hymenostomatida, Ciliophora) in ornamental fish.

For systemic therapy against trophozoites of the skin-inhabiting stage of Ichthyophthirius multifiliis in ornamental fish, the latter were fed medicated food flakes containing malachite green once daily for 1-11 days ad libitum. Naturally or artificially infected cardinal tetras (Paracheirodon axelrodi), blue gouramis (Trichogaster trichopterus), or clown loach (Botia macracantha) were used in the trials. The fish were maintained in aerated 12.5- or 60-1 aquaria at 23 degrees C. Ultrastructural investigations (scanning and transmission electron microscopy) revealed clear deleterious effects of malachite green on the parasitic stages. Following the initial application, the inner membrane of the mitochondria was destroyed. In fish fed for 2 days, aggregation of the mucocysts and polymerization the microtubules within the macronucleus occurred. Finally, the trophozoite's membrane was completely destroyed. In fish fed for 4 days, the medicated food killed all trophozoites of I. multifiliis. Sensitive ornamental fish (e.g., P. axelrodi) showed no adverse effects after they had been fed with only the medicated food flakes for 2 months. Therefore, the oral administration of malachite green using this newly developed medicated food considerably reduces the risk of toxic effects on the fish hosts, which are sometimes caused by malachite green following its application by immersion therapy. The feeding of flakes medicated with malachite green provides and easy-to-handle and highly effective treatment of I. multifiliis in ornamental fish.

Animal Feed↗
PubMed1992

Retrospective approach to explain growth retardation and urolithiasis in a child with long-term nutritional acid loading.

An infant with phenylketonuria unintentionally received a highly acidic low phenylalanine diet for 29 months. Temporary growth retardation and urolithiasis were observed, probably as direct effects of chronic acid loading. Caries at the age of 6 years may be a late consequence. This case report shows that chronic dietary acid load may cause serious side effects.

Acid-Base Equilibrium↗
PubMed1992

Development of height and weight in children with diabetes mellitus: report on two prospective multicentre studies, one cross-sectional, one longitudinal.

Optimal regimen for insulin therapy should lead to normal longitudinal growth and weight gain in children with diabetes mellitus. However, reports published so far indicate that this goal of paediatric diabetology is currently not achieved in a considerable number of patients. In a cross-sectional sample of 89 children with insulin dependent diabetes mellitus (IDDM) for more than 3 years, we found the relation of height to weight to be significantly different compared to 102 healthy school children of similar age. Using bivariate analysis, body shape in these children with diabetes was shifted towards small and obese (P less than 0.05) compared to control children. We subsequently initiated a longitudinal study and followed children from the onset of diabetes for the following 3 years, recording height, weight and bone age as well as glycosylated haemoglobin and daily insulin requirement. At diagnosis, height SDS was identical in children with IDDM (+0.04 +/- 0.10) compared to control children (-0.07 +/- 0.10; M +/- SE), while weight SDS was -0.26 +/- 0.10 in children with diabetes (controls: + 0.01 +/- 0.01). Bone age was identically retarded in newly diagnosed IDDM children (-0.73 +/- 0.12 SDS) and in our control group of children from the same regional background (-0.50 +/- 0.12; n.s.). In this group of children with diabetes mellitus followed prospectively, height to weight relationship differed from controls after 2 and after 3 years of the disease (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Flow cytometric analysis of uterine sarcoma: ploidy and S-phase rate as prognostic indicators.

Flow cytometry of various gynecological tumors has shown that aneuploid tumors and a high S-phase rate carry a prognosis worse than that of diploid tumors or tumors with a low S-phase. The aim of this study is to investigate the prognostic importance of DNA ploidy and S-phase rate in relation to mitotic count, tumor stage, tumor grade, and histology in 37 patients with uterine sarcoma stages I-IV (FIGO). Flow cytometry was performed on archival paraffin-embedded tumor tissue and the histologic specimens were reviewed by a single pathologist. Nineteen (51%) of the tumors were classified as DNA aneuploid. The S-phase fraction (SPF) was determined in 33 cases. The mean SPF (+/- SD) was 15.0% (+/- 9.5%). The mean SPF was three times higher in aneuploid tumors than in diploid cases. Both the proportion of aneuploid tumors and the mean SPF were significantly higher in later stage tumors, more poorly differentiated tumors, and tumors with a higher mitotic index. No significant differences were seen between histologic types with respect to the two cytometric variables. The 5-year cancer survival rate was only 11% in aneuploid cases compared with 59% in diploid cases (log rank, P = 0.0002). There was a significantly worse prognosis in cases with a higher SPF (P = 0.0009) and in case with a higher mitotic index (P = 0.0016). In the multivariate survival analysis using the Cox proportional hazards model, DNA ploidy showed a significant prognostic value (P = 0.046) even when adjusted for stage, grade, and mitotic index. When adjusted for stage and grade only, SPF showed significant additional prognostic value.

Adult↗
PubMed1992

[Histochemical light and electron microscopic investigations on an eosinophilic granuloma].

An eosinophilic granuloma has been investigated by means of histochemical proofs for enzymes and tissue elements and common staining methods. The best method was be found the proof for the enzyme phenol oxidase (EC 1.14.18.1). In this way it is possible to determine eosinophils rapidly and surely and to receive an overview on the frequency and distribution of these cells. The histiocytic-like cells was identified electron microscopical as Langerhans' cells. This cells are in narrow contact to many eosinophilic granulocytes. Their granula have manifold changes in their structure. The granula are possibly able to produce new structures of the cell. The eosinophilic granuloma correspond to a cell mediating immunological defence reaction approximate to the type of a delayed hypersensitivity.

Acid Phosphatase↗
PubMed1992

Mdr1/P-glycoprotein, topoisomerase, and glutathione-S-transferase pi gene expression in primary and relapsed state adult and childhood leukaemias.

In a variety of adult and childhood leukaemia cell samples collected at different states of the disease, we analysed in a series of sequentially performed slot-blot or Northern-blot hybridisation experiments the expression of genes possibly involved in multiple drug resistance (MDR) (mdr1/P-glycoprotein, DNA topoisomerase II, glutathione-S-transferase pi), and the expression of the DNA topoisomerase I and histone 3.1 genes. Occasionally, P-glycoprotein gene expression was additionally examined by indirect immunocytofluorescence using the monoclonal antibody C219. No significant difference in mdr1/P-glycoprotein mRNA levels between primary and relapsed state acute lymphocytic leukaemias (ALL) was seen on average. Second or third relapses, however, showed a distinct tendency to an elevated expression of this multidrug transporter gene (up to 10-fold) in part well beyond the value seen in the moderately cross-resistant T-lymphoblastoid CCRF-CEM subline CCRF VCR 100. Increased mdr1/P-glycoprotein mRNA levels were also found in relapsed state acute myelogenous leukaemias (AML), and in chronic lymphocytic leukaemias (CLL) treated with chlorambucil and/or prednisone for several years. Topoisomerase I and topoisomerase II mRNA levels were found to be very variable. Whereas in all but one case of CLL topoisomerase II mRNA was not detected by slot-blot hybridizations, strong topoisomerase I and topoisomerase II gene expression levels, frequently exceeding the levels monitored in the CCRF-CEM cell line, were seen in many cell samples of acute leukaemia. If topoisomerase II mRNA was undetectable, expression of topoisomerase I was clearly visible throughout. These observations might be valuable considering the possible treatment with specific topoisomerase I or topoisomerase II inhibitors. Significant positive correlations were found (i) for topoisomerase I and histone 3.1 gene expression levels in general (P less than 0.001), and (ii) in the CLL samples additionally for the expression levels of the mdr1 gene, and the histone 3.1, topoisomerase I, and glutathione-S-transferase pi genes, respectively.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

[Anesthesia and acute hepatic porphyrias].

Acute hepatic porphyrias are inherited disorders of heme biosynthesis. A characteristic feature of acute porphyrias is the occurrence of acute attacks which are often precipitated by drugs. Many of the commonly used anaesthetic agents may trigger such a potentially lethal attack. Thus, only safe agents should be administered to predisposed patients. Recommendations given are based on results from animal experiments and on a series of anecdotal reports. Regional anaesthesia is presented as anaesthetic technique of choice. General anaesthesia should be based on a fentanyl-nitrous oxide regimen, with propofol as induction agent. In the case of an acute attack, treatment consists of glucose and haematin administration.

Anesthetics↗
PubMed1992

[Suture fixation of a Swan Ganz catheter to the left brachiocephalic vein during re-thoracotomy].

This case report describes the intraoperative fixation of a Swan-Ganz catheter at the left brachiocephalic vein by a suture during rethoracotomy in a cardiac surgical patient. In case of a rethoracotomy by median sternotomy the right-sided veins should be preferred for the insertion of a Swan-Ganz-catheter. Furthermore the free mobility of the catheter should be controlled before closure of the thorax.

Brachiocephalic Veins↗
PubMed1992

Nosocomial sinusitis in ventilated patients. Nasotracheal versus orotracheal intubation.

A total of 68 postoperative patients whose lungs were ventilated for more than 4 days were studied prospectively during a one-year study period to investigate the effect of the mode of intubation on the paranasal sinuses. After an initial X ray of the skull showing no pathological findings, patients were assigned randomly to one of the study groups; the lungs of patients in group A were ventilated via an orotracheal tube (n = 32), and patients in group B via a nasotracheal tube (n = 36). X ray examinations of the sinuses were performed at regular intervals. Diagnosis of sinusitis was confirmed by transantral needle puncture and culture of fluids obtained. Antibiotic regimens were altered according to laboratory testing. Two patients in group A developed signs of sinusitis in comparison to 15 patients in group B (p less than 0.01). However, there were significantly more airway complications in the orotracheal group, particularly during the period of weaning from ventilation. We conclude that orotracheal intubation should be preferred as the routine route of intubation.

Aged↗