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Biomedical subjects

H Weber

Publications and source records attributed to H Weber.

At least 415 records · Page 23Linked to original sources
PubMed1984

[Ergometry and long-term ECG for assessing bradycardiac and tachycardiac heart rhythm disorders in symptomatic patients over 70].

The usefulness of exercise testing and long term-ECG recording in old age was evaluated in a retrospective study. During a period of 24 months 317 long-term-ECGs in 195 patients greater than 70 years and 208 exercise tests in patients greater than 70 years were performed. The mean age of the patients was 73 +/- 3 years. Long-term ECG revealed a high incidence of supraventricular arrhythmias, while PVCs were found in only 28.7% of patients and PVCs greater than 30/h in only 7.3% of patients. Complex ventricular arrhythmias occurred in 25% of patients. Long-term ECG recording appeared to be of particular value in detecting abnormal regulation of heart rate and bradycardia, although symptom correlation with arrhythmias recorded was rare. Exercise testing revealed a higher incidence of PVCs with PVCs recorded in 67% of patients and PVCs greater than 2/min in 42% of patients. The incidence of complex ventricular arrhythmias was slightly greater compared to long-term recording with 29% of all patients. Exercise testing was particularly useful in detecting complex arrhythmias in patients with additional signs of myocardial ischemia (ST-segment depression and/or angina pectoris during increasing levels of exercise). Thus comparing both exercise testing and long-term ECG both appeared to be useful methods to uncover arrhythmias in symptomic patients older than 70 years and have to be considered as complementary tools. Exercise testing is particularly useful in recovering complex ventricular arrhythmias in patients with signs of myocardial ischemia during exercise. Long-term ECG on the other hand allows better recognition of bradycardias and conduction defects that may also be present and may contribute to the patients symptoms.

Aged↗
PubMed1984

Autotraction versus manual traction in patients with prolapsed lumbar intervertebral discs.

Forty-nine patients with lumbago-sciatica and prolapsed lumbar intervertebral discs, comparable concerning anamnestical and clinical data were randomized for autotraction and manual traction given by the same therapist for a period of one week while strict bed rest was prescribed. A blind overall assessment performed immediately after the traction period, after two weeks follow-up training and three months after hospitalization showed that the two traction modalities are equally efficient. As treatment for hospitalized patients with lumbar intervertebral disc prolapses the relatively simple manual traction variety should be preferred, if any. Traction is suggested to be used as a prognostical aid. Pain intensity was significantly reduced in all body parts. About one fourth of patients avoided operation. After two years there was no recurrence of symptoms.

Adolescent↗
PubMed1984

Chylopericardium: a rare cause of pericardial effusion.

A 21 year old man presented with asymptomatic, isolated chylopericardium. Despite echocardiography, radionuclide-angiography, computer tomography, and chemical analysis of the chylous effusion, the etiology remained obscure. After patent blue dye infusion into peripheral soft tissues, the appearance of coloring material in the effusion at 4 hours suggested direct communication of the pericardium with an apparently large thoracic duct. Fifteen months later, cardiomegaly persists in site of medium-chain triglyceride dietary restriction.

Adult↗
PubMed1983

Formation of genes coding for hybrid proteins by recombination between related, cloned genes in E. coli.

We describe a method for the formation of hybrid genes by in vivo recombination between two genes with partial sequence homology. DNA structures consisting of plasmid vector sequences, flanked by the alpha 2 interferon gene on the one side and a portion of the alpha 1 interferon gene (homology about 80%) on the other, were transfected into E. coli SK1592. Appropriate resistance markers allowed the isolation of colonies containing circular plasmids which arose by in vivo recombination between the partly homologous interferon gene sequences. Eleven different recombinant genes were identified, six of which encoded new hybrid interferons not easily accessible by recombinant DNA techniques.

Amino Acid Sequence↗
PubMed1983

Evaluation of amitrole (aminotriazole) for potential carcinogenicity in orally dosed rats, mice, and golden hamsters.

Amitrole was evaluated for carcinogenic potential in lifespan studies on Wistar rats, NMRI mice, and golden hamsters. At the start of the studies the animals were 6 weeks old. Amitrole was administered, mixed with pulverized chow, at dietary concentrations of 0, 1, 10, and 100 micrograms/g (ppm). Each treated group and control group consisted of 75 male and 75 female rats and mice and of 76 male and 76 female golden hamsters. Additional animals were used to evaluate the functional state of the thyroid. Somewhat lower body weights, slightly reduced survival times, and transient effects on thyroid function were observed in golden hamsters at 100 ppm. In mice, a slight increase in pituitary gland hyperemias was seen at 100 ppm; also an effect on thyroid function usually occurred at the same concentration. In rats, a very large number of cystic dilatations of follicles in the thyroid at 100 ppm and a dose-unrelated increase in hemorrhages and hyperemias in the pituitary gland were indicative of an effect of amitrole on these organs. The strongest effect of amitrole on thyroid function, as compared to golden hamsters and mice, was seen in rats at 100 ppm. At this concentration a highly increased number of thyroid and pituitary gland tumors was observed in rats. In golden hamsters and mice, no tumor induction was seen.

Amitrole↗
PubMed1983

[Modern aspects of cardiogenic shock].

Since the introduction of coronary care units the in-hospital mortality decreased in acute myocardial infarction (AMI), but not the mortality which persisted at about 90% in cardiogenic shock (CS). the definition of CS is based on a cardiac index of greater than 2.2 1/min/m2 and an advancing lactate acidosis with lactate values of about 4.0 mmol/1 which leads to death in most cases by the so-called secondary ventricular fibrillation. Measurements of invasive haemodynamic parameters like cardiac index etc. were superseded by clinical parameters because of methodological problems in clinical routine. Forrester deals with clinical parameters and the pulmonary wedge pressure to separate 4 haemodynamically different subsets in the acute stage of AMI. The treatment of cardiogenic shock uses the manipulation of pre- and/or afterload. Nitrates reduce an increased PCV to normal values because of dilating the capacity vessels (preload) which leads to venous pooling. The cardiac index increases up to 20%. Vasodilators (Na-nitroprusside, phentolamine, prazosin, hydralazine, captopril) also caused an increase of the cardiac index because of afterload reduction. This therapeutic strategy demands exact continuous arterial blood pressure monitoring. A perfusion pressure greater than 80 mm Hg on an average will extend the infarction area in narrowed coronary arteries. Positive inotropic drugs (dopamine, dobutamine, amrinone) increase the contractility of the injured myocardium. From the haemodynamic point of view the best results can be achieved by application of temporary intraaortic counterpulsation (IABP) by reducing afterload and increasing diastolic perfusion of the coronary arteries. Nevertheless IABP is of restricted value because of high rate of pump-dependence.

Hemodynamics↗
PubMed1983

Genetic studies on the yeast Saccharomycopsis lipolytica. Inactivation and mutagenesis.

Spontaneous mutants of Saccharomycopsis lipolytica were selected and partially characterized. Several antibiotics and antimetabolites were used for selection of spontaneous resistant mutants from Saccharomycopsis lipolytica. The frequencies of such mutants were mainly arranged between 1 X 10(-7) and 5 X 10(-6) mutants per cell. But one class of glucosamine resistant mutants (GAMRA) occurred more frequently. Among the resistant mutants different types of dominant and recessive resistant mutants could be observed. UV light was used for inactivation of cells and induction of mutants from S. lipolytica. Comparing four haploid strains only small differences were detected in sensitivity to UV light. UV light at a dosage of 135 J/m2 was applied to increase the mutant frequencies in three haploid strains. Besides auxotrophic, temperature sensitive and colony morphology mutants, some new mutant types like small colony forming mutants, red-brown coloured mutants, some new mutant types like small colony forming mutants, red-brown coloured mutants, allylalcohol, glucosamine, 2-deoxyglucose or nystatin resistant mutants, hitherto not described for S. lipolytica, were isolated and partially characterized.

Ascomycota↗
PubMed1983

Reversible EOL-indicator: a new cause for low pacemaker rate.

A case is presented in which a new cause for decrease in pacemaker rate was encountered: six months after implantation of a Medtronic 5967 pacemaker, the first routine check-up revealed a rate of 62.5 ppm instead of 70 ppm. After application of a magnet, all measurements returned to normal. The cause for this phenomenon, which could not be attributed to battery depletion or oversensing, was probably a change of state of the flip-flop which is responsible for the sudden rate drop of 10% which serves as the end-of-life (EOL)-indicator in this pacemaker. This change of state may result from a very short decrease of power supply voltage during shipment or at the time of implant, and is fully and permanently reversible by performance of the magnet test. In order to prevent unnecessary pacemaker explants, future pacemaker circuits should be redesigned to eliminate the effect of very short voltage changes. Meanwhile, a routine magnet test should be performed immediately after implantation.

Electric Power Supplies↗
PubMed1983

First clinical trial with iohexol in myelography.

This is a report of the first clinical trial with iohexol in lumbar myelography. The investigation was carried out as an open, non-comparative study in 30 patients and was part of a multicentre trial. Iohexol doses of 10 to 15 ml (180 mg I/ml) were used and clinical and laboratory tests were performed before and during 48 h after myelography. Spinal repuncture 6 or 24 h after myelography was done in all patients. Only minor side effects of temporary duration were recorded in 8 patients. No seizures or spikes on EEG were seen. There was no significant increase in CSF parameters such as white cell counts, protein or IgG.

Cerebrospinal Fluid Proteins↗
PubMed1983

Development of breeding stocks of the yeast Saccharomycopsis lipolytica by methods of moderate inbreeding.

Sporulation parameters of genetically labelled strains, derived from a wild strain of the alkane-utilizing yeast Saccharomycopsis lipolytica were improved by a breeding program using brother-sister crosses. Sporulation frequency, the number of four-spored asci and viability of ascospores could be significantly enhanced. To date a number of genetically well-defined strains is available that have good sporulation parameters and show a 1:1 segregation pattern of markers suitable for genetic analysis.

Ascomycota↗