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Biomedical subjects

H Vogt

Publications and source records attributed to H Vogt.

At least 73 records · Page 4Linked to original sources
PubMed1989

Afterload dependence of cardiac contraction parameters.

In rabbits the afterload dependence of baroreflex inotropy was studied, based on the contraction parameters CI = (dP/dt/P)max and a systolic time interval RP. These were estimated 1. for stepwise aortic coarctation and 2. for aortic nerve stimulation under pressure clamp conditions. CI is enhanced by aortic pressure elevation whereas RP is shortened. Aortic nerve stimulation caused higher CI and RP effects at free-running pressure than under pressure clamp conditions. The RP effects are always smaller. For clamping at low holding pressures the CI effects are higher and vice versa, whereas the RP effects are nearly independent of pressure. These results show that baroreflex inotropy, generally, is influenced by concomitant afterload changes, but the CI parameter and its inotropic effect is more afterload-dependent than RP.

Animals↗
PubMed1988

Specific recognition of the 3'-terminal adenosine of tRNAPhe in the exit site of Escherichia coli ribosomes.

Ribosomes from Escherichia coli possess, in addition to A and P sites, a third tRNA binding site, which according to its presumed function in tRNA release during translocation has been termed the exit site. The exit site exhibits a remarkable specificity for deacylated tRNA; charged tRNA, e.g. N-AcPhe-tRNAPhe, is not bound significantly. To determine the molecular basis of this discrimination, we have measured the exit site binding affinities of a number of derivatives of tRNAPhe from E. coli, modified at the 3' end. Binding to the exit site of the tRNAPhe derivatives was measured fluorimetrically by competition with a fluorescent tRNAPhe derivative. We show here that removal of the 2' and 3' hydroxyl groups of the 3'-terminal adenosine decreases the affinity of tRNAPhe for the exit site 15 and 40-fold, respectively. Substitutions at the 3' hydroxyl group (aminoacylation, phosphorylation, cytidylation) as well as removal of the 3'-terminal adenosine (or adenylate) of tRNAPhe lower the affinity below the detection limit of 2 x 10(5) M-1, i.e. more than 100-fold. Modification of the adenine moiety (1,N6-etheno adenine) or replacement of it with other bases (cytosine, guanine) has the same dramatic effect. In contrast, the binding to both P and A sites is virtually unaffected by all of the modifications tested. These results suggest that a major fraction (at least -12 kJ/mol, probably about -17 kJ/mol) of the free energy of exit site binding of tRNAPhe (-42 kJ/mol at 20 mM-Mg2+) is contributed by the binding of the 3'-terminal adenine to the ribosome. The binding most likely entails the formation of hydrogen bonds.

Adenosine↗
PubMed1988

Effect of androgens on the response to antithymocyte globulin in patients with aplastic anaemia.

30 patients with aplastic anaemia (18/30 with severe aplastic anaemia) were prospectively randomized to be treated with 100 mg/kg ATG with or without the oral androgen Methenolone (3 mg/kg). 15 of 30 patients responded. Among the 15 patients receiving ATG plus androgen, 11 patients (73%) responded, including 8 complete and 3 partial responses. 4 of the 15 patients (31%) receiving ATG only responded, including 2 complete and 2 partial responses. The difference in response rate was statistically significant (p = 0.01). The survival rate in the total population of 30 patients was 64%. The survival rate in the group receiving ATG plus androgen was 87%; in the group receiving ATG only it was 43%. The difference in survival rates between both groups did not reach statistical significance (p = 0.15). Toxicity of ATG and androgens was considerable but manageable. These data support the result of the recent European reevaluation of a large pool of patients by the EBMT (39), that androgens in addition to ATG increase survival in patients with aplastic anaemia. They are, however, in contradiction to a controlled American study showing no benefit of a combined treatment with androgens as compared to ATG only. Further controlled studies on a larger number of patients are indicated to determine the therapeutic efficacy of androgens in addition to immunosuppression in aplastic anaemia.

Androgens↗
PubMed1988

Reproductive performance of hens fed field beans and potential relationships to vicine metabolism.

Field beans (faba beans, broad beans, horse beans, ackerbohnen, Vicia faba L.) depress weight of eggs when fed to laying hens. Vicine isolated from field beans has been shown to depress egg weight and hatchability when fed in large amounts. The present study was undertaken to determine the effect of using three varieties of field beans, varying in tannin and total vicines content, at 20% in breeder diets on reproductive performance of hens and associated vicine transfer from the diet to the egg. Data on egg production, feed consumption, egg weight, body weight, egg quality, hatchability, and hen blood chemistry were obtained. Direct spectrophotometric and high pressure liquid chromatographic (HPLC) analyses of field beans, egg albumen, and egg yolk were conducted. Performance of the hens was excellent on all production characteristics except that there was a nonsignificant reduction in egg weight, a significant reduction in egg shell thickness for hens fed all three types of field beans, and a highly significant reduction in hatchability of eggs from hens fed one but not the other two sources of field beans. The hatchability effect was not correlated with vicine or tannin content of the field beans and only traces of vicine were transferred to the egg by the hen from the diet. Although larger amounts of vicine depressed hatchability when injected into fertile eggs, the trace amounts found in eggs from feeding field beans did not account for the reduction in hatchability observed in this study. It is possible that the hydrolysis product of vicine, divicine or the analogous product from convicine, isouramil, or both, may be involved in toxicity, because these substances are known to be the cause of a hemolytic anemia in some humans that suffer from favism due to consumption of field beans.

Animal Feed↗
PubMed1987

[Cognitive performance profile in schizophrenic patients].

The cognitive abilities of 189 schizophrenics were investigated by standard tests of intelligence, verbal and non-verbal, selected according to current models of information processing in schizophrenia, to show a specific cognitive deficit. The diagnostic procedure followed the St. Louis research diagnostic criteria. The following cognitive profile has been found: Good verbal abilities and good abilities in verbal abstractions, middle-sized deficit in non-verbal intelligence and non-verbal abstractions but also in cognitive accuracy and in the range of attention. The deficit in concentrations was very high. This characteristic cognitive profile is very useful for the rehabilitation of the patients and probably also for the diagnosis.

Attention↗
PubMed1986

The use of high-frequency jet-ventilation in operative bronchoscopy.

The authors report on the use of HFJV in operative laser fibre-optic bronchoscopy, especially in combination with the laser technique. The method and initial results are discussed. Also high-risk patients can be treated with this method without the need for general anaesthesia.

Anesthesia, Local↗
PubMed1982

Measurement of prostatic acid phosphatase in serum and bone marrow: radioimmunoassay and enzymic measurement compared.

We quantitated the concentrations of prostatic acid phosphatases (EC 3.1.3.2) in serum and bone-marrow aspirates with three commercial radioimmunoassay kits, and the catalytic activities with a thymolphthalein monophosphate-based enzyme test. The enzyme's immunological activity in serum was compared with its catalytic activity for its potential as a detector of early prostatic cancer and its performance as an early marker of metastatic activity in bone. Neither measurement is useful for detecting early stages of prostatic cancer. The spread of carcinoma to lymph nodes or to bone is detected with greater frequency by radioimmunoassay than by the enzymic test. Radioimmunoassay also detected metastasis to the bone more frequently than did physical methods. Analytical and clinical performance of the four methods is described.

Acid Phosphatase↗
PubMed1981

Clinical assessment of gestational age in the newborn infant. An evaluation of two methods.

The scoring systems of Dubowitz et al. and Parkin et al. were evaluated in two selected materials of newborn infants referred to a neonatal unit. Our estimation of gestational age by Dubowitz scores tended to be too high for the extreme prematures. "Small-for-dates" were also overestimated, whilst "appropriate-for-dates" and infants with respiratory difficulties were underestimated. "Large-for-dates" fell close to the standard curve. Ninety-five per cent confidence limits were up to +/- 5 weeks for Dubowitz scores and nearly +/- 6 weeks for Parkin scores. Further statistical analysis displayed some limitations in the use of linear regression formulas for scoring systems based on external and/or neurological characteristics. Thus, the results obtained with these methods must be used with caution in some selected newborn materials.

Birth Weight↗
PubMed1979

[Radio-nuclide phlebography: methods, indications and clinical value (author's transl)].

Radionuclide venography (RNV) is an easily performed, rapid and non-invasive diagnostic examination for the detection of deep-vein thrombosis. Provided the procedure is followed out in a standardized order, the results are highly reliable and accurate, especially in the iliac and femoral veins. Therefore, because of this advantage and the possibility of simultaneous lung perfusion scanning and the lack of serious complications this method fills a gap between contrast phlebography and fibrinogen test. 122 limbs of 69 patients were investigated by RNS. 65% showed pathologic results. In 48% thrombotic venous occlusions could be demonstrated. Pulmonary embolic perfusion defects were found in 46% of patients presenting deep vein thrombosis but only in 15% of patients without pathologic findings in RNV. In correlation with contrast phlebography in 11 patients there was no discrepancy neither in recognition nor in localization of the thrombotic occlusion. The essential findings in RNV and the resulting diagnostic conclusions are demonstrated.

Humans↗