Search PubMed⌕ Search

Biomedical subjects

U Schmidt

Publications and source records attributed to U Schmidt.

At least 469 records · Page 26Linked to original sources
PubMed1979

[Subtotal parathyroidectomy in the advanced stages of renal osteodystrophy].

In 7 haemodialysis patients with progressing renal osteopathy a partly subtotal, partly total parathyroidectomy was carried out. Postoperatively in all cases a clinical improvement developed, which, however, in part was only transient. The laboratory parameters showed a rapid tendency to normalisation, the X-ray diagnostic finding and the bone mineral content remained essentially unchanged, also the histological skeletal findings. The results are compiled in form of tables. The value of the diagnostic measures which should precede a subtotal parathyroidectomy is discussed. At present the different postoperative courses apparently cannot be prospectively estimated with the help of the hitherto usual diagnostic measures. On the basis of the partly good results and of the operation risk which is to be thoroughly demanded of a haemodialysis patient it seems that after having used all conservative possibilities the surgical interventions nevertheless indicated in progressing renal osteopathy.

Adult↗
PubMed1978

[Results of veterinary tumor research and their significance for practice].

Enzootic bovine leucosis and Marek's disease of fowl are the most important tumour diseases of farm animals, with the greatest repercussions on the national economy, today. Experimental findings obtained from either disease in recent years are reported in this paper, and an assessment is made of their importance to practice. In the context of enzootic bovine leucosis, particular reference is made to those findings which helped to establish the presence of virus infection, results by which the pathogen could be characterised, and to studies undertaken with the view to devising methods for virologico-serological diagnosis. In the context of Marek's disease, reference is made to virological, epizootiological, and diagnostic aspects, however, with emphasis being laid on possibilities for immunisation and, in that connection, on known fundamental concepts for successful immunoprophylaxis against that tumour disease.

Animals↗
PubMed1978

Liver cell heterogeneity. The distribution of fructose-bisphosphatase in fed and fasted rats and in man.

Periportal and perivenous hepatocytes were isolated by microdissection from lyophilized liver slices (16 micrometer) from fed and fasted rats and from a human patient. NADP/NADPH cycling was used to determine fructose-1,6-bisphosphatase activity in the isolated hepatocytes (10 ng dry weight). The periportal hepatocytes contain 3 times as much fructose-1,6-bisphosphatase activity as the perivenous hepatocytes. A 24 h fast led to two-fold increase in the activity in the periportal hepatocytes and a four-fold increase in the perivenous hepatocytes. Fructose-1,6-bisphosphatase parallels closely with the key enzyme phosphoenolpyruvate carboxykinase, and therefore can be considered a suitable marker for gluconeogenic capacity.

Animals↗
PubMed1978

[2 1/2-year experience with highly-effective short-term dialyses in Erfurt].

At present 18 of 19 dialysis patients undergo the highly effective short-term dialysis, which is used in the Erfurt centre since November 1974. The therapy is performed by two parallel dialysators C-DAK 4 for 3 to 4 hours (24.4 square metres -- hours/week). During the period of observation of 2 1/2 years altogether 35 patients were treated with the short-term dialysis. There are compared clinical and paraclinical parameters of 12 patients who on an average for 2 years underwent the short-term dialysis. The serum levels of retained substances of protein and albumin as well as the "optimum weight" did not or only unessentially differ from each other. Also the blood pressure values scarcely deviated from each other before and after dialysis. The manifold use of the C-DAK 4 is the cause for an increased substitution of erythrocytes. Insufficient compensation of the circulation and a low body weight are regarded as contraindication to the short-term dialysis.

Adolescent↗
PubMed1978

Effect of storage and processing on tetracycline residues in meat and bones.

A semiquantitative microbiological screening test for antibiotics, a sensitive and quantitative microbiological assay, and a fluorometric method specific for tetracyclines are described. Using these procedures, tetracycline residues in animals derived from feed can be detected in tissues like organs, muscles, and bones. Meat contaminated with chlortetracycline (CTC) and oxytetracycline (OTC) and stored at +8 degrees C and -22 degrees C showed very little decrease in antibiotic concentration; however, heating above 65 degrees C reduced the tetracycline content in meat. Temperatures above 130 degrees C were necessary to destroy CTC in bones, CTC in bones was insoluble above pH 4. Manufacturing products with contaminated meat reduced the tetracycline content only if heating was involved.

Animal Feed↗
PubMed1977

[Silymarin for the treatment of acute viral hepatitis? Report of a controlled trial (author's transl)].

Silymarin has been claimed to have a benificial effect in various types of liver injury. In a prospective study in patients with acute viral hepatitis (n = 151) the effectiveness of this drug on the cause of the disease was tested. The groups with and without Silymarin (Legalon) were comparable concerning age and sex distribution and the frequency of HBs-antigen positive hepatitis; Laboratory findings (total serum bilirubin, activity of GOT, GPT and alkaline phosphatase and prothrombin time) were determined in intervals of 5 to 7 days over a period of 5 weeks beginning with the onset of jaundice. There were no statistical significant differences between both groups in the decrease of mean values of all parameters tested. The frequency of nearly normalized values of transaminases and serum bilirubin after 10, 20 and 30 days was not higher in the group treated with Silymarin as compared to the controls. It is concluded that Silymarin has no favourable effects on the cause of acute viral hepatitis.

Adolescent↗
PubMed1977

Effect of papaverine on the frequency-force relationship in guinea-pig left atria.

Contractile responses of guinea-pig atria to papaverine were analyzed under different stimulation frequencies. Atria, driven at 2 Hz, showed positive inotropic responses to papaverine which were maximal within 10-15 min. These responses were maintained for 60 min in the presence of low concentrations of papaverine (up to 10(-5) M), but reversed into marked negative inotropic effects under the influence of higher concentrations. The well-known frequency-force relationship was reversed by papaverine. At low stimulation rates papaverine elicited positive inotropic responses, which gradually decreased with increasing frequencies until strong cardiodepression occurred. A frequency-force curve obtained in the presence of both the Ca2+-antagonistic drug D 600 and the inhibitor of the phosphodiesterase theophylline was similar to that obtained under the influence of papaverine. Theophylline alone evoked positive inotropic effects at all frequencies studied and left the character of the ascending staircase unchanged. In contrast, D 600 was ineffective at low, but cardiodepressive at high stimulation frequencies. In the presence of D 600 or papaverine high external Ca2+ could not restore a normal frequency-force relationship. The reversal of the frequency-force relationship as produced by D 600 and papaverine could not be obtained by lowering of the external Ca2+. The present results show that papaverine is able to evoke marked positive inotropic effects at low stimulation frequencies by inhibition of phosphodiesterase. At high frequencies, however, these effects are masked by negative inotropic responses due to the inhibitory action of papaverine on Ca2+-exchange of the cardiac muscle cell.

Animals↗
PubMed1977

H1 - and H2-receptor mediated responses to histamine on contractility and cyclic AMP of atrial and papillary muscles from guinea-pig hearts.

On guinea-pig heart we investigated whether cyclic AMP serves as a messenger for H1 - and/or H2-mediated responses to histamine. (1) On papillary muscle histamine elicited positive inotropic responses which were antagonized by burimamide but not by promethazine. The stimulation of H2-receptors was not only associated with an increase in contractility but also with an increase in cAMP. As shown by the time course of effects for 10(-5) M histamine, the maximal increase in cAMP preceded the maximum in contractility. The mechanical and biochemical responses to histamine were potentiated by the phosphodiesterase inhibitor papaverine, but antagonized by burimamide. (2) On the left guinea-pig atrium containing H1-receptors the inotropic response to histamine (10(-5) M) was not accompanied by increases in cAMP at stimulation frequencies of 0.5 and 2 Hz, respectively. In addition, in the presence of papaverine (3 X 10 (-5) M) no change in the cyclic AMP level occurred after application of histamine. Papaverine by itself, however, concomitantly increased contractility and cyclic AMP at a stimulation frequency of 0.5 Hz. In contrast, at 2 Hz papaverine increased only cAMP leaving the contractility unchanged. At this frequency the well-known Ca2+-antagonistic effect comes into prominence, thus masking the positive inotropic effect attributable to the inhibition of the phosphodiesterase. (3) On the right guinea-pig atrium the mediation of the positive chronotropic response to histamine by H2-receptors which is partly involved in the inotropic effect via the frequency-force relationship does not lead to a concomitant increase in cAMP. Also, in the presence of papaverine, histamine had no influence on the cAMP. However, papaverine potentiated the cardioacceleration produced by histamine. Although it is very likely that the cAMP in the sinus node rises, we were not able to detect an increase in cAMP in the whole atrial tissue. From the present results the conclusion can be drawn that the mediation of the inotropic effect due to stimulation of H2-receptors by histamine is associated with an increase of cyclic AMP, whereas that of H1-receptors is not. The view that cAMP may be the second messenger in the chronotropic action of histamine needs further elucidation by experiments on sino-atrial cells.

Animals↗
PubMed1977

Echolocation performance of the vampire bat (Desmodus rotundus).

The neotropical vampire bats (Desmodus rotundus) echolocate using ultrasonic pulses like those of the Latin American phyllostomatid bats. In this paper the orally produced echolocation sounds of Desmodus are analysed and the performance of the echolocation system is studied in two-choice training experiments on two vampire bats. Ability to detect objects is relatively limited; both animals were capable of discerning the presence of a 1 cm wide metal strip at a distance of 50 cm, but they failed with 0.5 cm wide strips. The ultrasonic pulses produced at a distance of 50 cm appear to sample an area with a diameter of 2.5 to 3.0 cm (i.e., the solid angle tested with each pulse is 3 degrees to 3 degrees 40' in extent).

Animals↗