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Biomedical subjects

H Hartmann

Publications and source records attributed to H Hartmann.

At least 199 records · Page 11Linked to original sources
PubMed1985

Chromatographic studies on the radiolysis of DNA in aqueous solution.

Radiation-induced degradation of double-stranded DNA from calf thymus in aqueous solution with sodium phosphate was studied by conventional gel chromatography and by high-performance liquid-gel permeation chromatography. Comparison of the data after radiolysis of aqueous solutions of DNA under anaerobic and aerobic conditions indicates that double-strand breakage is not enhanced by oxygen. An increase of ionic strength impedes the break-down of the DNA molecules, so that loss of DNA can only be observed at doses above 100 Gy. Only reactions of OH-radicals contribute to the fragmentation of DNA, while the presence of hydrated electrons, H.-or formate radicals does not lead to a loss of highly polymerized DNA up to doses of 1500 Gy. High-performance liquid-chromatography proved to be an excellent method of studying the degradation of macromolecules as a function of dose.

Chromatography, Gel↗
PubMed1985

Insulin-like action of proinsulin on rat liver carbohydrate metabolism in vitro.

Short-term effects of human proinsulin on metabolic rates and its long-term action on enzyme induction were studied in primary cultures of rat hepatocytes and in the perfused rat liver, and compared with the effects of bovine insulin. In the perfused rat liver, proinsulin decreased the glucagon-dependent increase of glycogenolysis. The action of 0.5 nM glucagon was almost completely suppressed by 100 nM proinsulin. Proinsulin and insulin showed similar potency. In cultured rat hepatocytes, proinsulin stimulated glycolysis up to fivefold with a half-maximal effective dose of 30 nM. Proinsulin induced the key glycolytic enzymes glucokinase and pyruvate kinase by twofold and antagonized the glucagon-dependent induction of phosphoenolpyruvate carboxykinase with a half-maximal effective dose at 3 nM. For the effects in cultured hepatocytes, about 100-fold higher concentrations of proinsulin than of insulin were required.

Animals↗
PubMed1985

[Modified holding therapy. A basic therapy in the treatment of autistic children].

Seven autistic children were selected at random from a group of 14 and treated with modified holding therapy (MHT) for 4 weeks. The remaining 7 children (control group) were not treated during a 4-week waiting period. Four of these children were then treated with MHT. The children's parents assessed positive behavior changes (increases in desirable behavior and decreases in undesirable behavior) and negative changes on a behavior rating scale. Significantly more positive changes in behavior problems were reported for the experimental group than for the control group (untreated group) in each of the four symptom categories assessed (disturbances in perception, in speech and in social interaction and obsessive-compulsive or ritualistic behavior). The 4 children in the control group who were later treated with MHT showed behavior changes that correlated highly with those reported for the experimental group. The results are discussed and interpreted from the viewpoint of the two-system theory of information processing and its meaning for psychoses.

Adaptation, Psychological↗
PubMed1984

Regulation of oxygen consumption in perfused rat liver: decrease by alpha-sympathetic nerve stimulation and increase by the alpha-agonist phenylephrine.

In livers perfused with Krebs-Henseleit bicarbonate buffer containing bovine red cells, 5 mM glucose and 2 mM lactate, electrical stimulation round the hepatic artery and the portal vein caused via alpha-receptors a decrease in oxygen consumption and portal flow, an increase in glucose output and a switch from lactate uptake to output. In livers perfused with erythrocyte- and substrate-free buffer both in a volume- or pressure-constant system stimulation of the liver nerves resulted in similar changes. Infusion of the alpha-agonist phenylephrine mimicked the metabolic and hemodynamic nerve effects, but led to an increase in oxygen uptake. The converse effects of alpha-sympathetic nerve stimulation and alpha-agonist infusion on oxygen consumption indicate either a different mode of action or a complex mechanism with opposing metabolic and hemodynamic components.

Animals↗
PubMed1984

Favourable outcome of hepatic veno-occlusive disease in a renal transplant patient receiving azathioprine, treated by portacaval shunt. Report of a case and review of the literature.

Veno-occlusive disease (VOD) developed in a 45-year-old white male 2 years after cadaveric kidney transplantation while receiving combined immunosuppressive therapy with prednisone and azathioprine. Early clinical signs at presentation included ascites and tender hepatomegaly. The diagnosis of VOD was established at laparoscopy and by histological examination of liver biopsies. Azathioprine was discontinued. Gross ascites refractory to medical treatment and decreasing liver function required surgical treatment by portacaval shunt. Transient postoperative complications were hepatic encephalopathy and considerable hyperbilirubinaemia. 8 months later the patient is well, with stable renal function and no clinical signs of hepatic disease.

Azathioprine↗
PubMed1984

Prolonged cholestatic jaundice and leukopenia associated with piroxicam.

A case of prolonged cholestatic jaundice and leukopenia occurring in a 60 year old wh piroxicam--a non-steroidal antiinflammatory agent--is reported. Histological examination of liver biopsy revealed pronounced canalicular and intracellular bile retention. After discontinuation of the drug serum bilirubin declined to normal values over a period of 10 weeks.

Anti-Inflammatory Agents↗