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Biomedical subjects

W Klein

Publications and source records attributed to W Klein.

At least 307 records · Page 17Linked to original sources
PubMed1990

[Pregnancy outcome with intensified insulin therapy in manifest diabetes].

In 1981, the intensified insulin therapy for achievement of euglycaemia in pregnant diabetics was introduced at the University Department of Obstetrics and Gynaecology in Cologne. This study compares the results of 112 pregnancies in women with overt diabetes monitored before (1971-1980) or after (1981-1988) changing the therapeutic regimen. In the period from 1981 to 1988, the proportion of euglycaemic patients (preconceptionally 19%, before delivery 79%) was clearly higher than from 1971 to 1980 (n = 42; 7% and 9%, respectively). The tight blood glucose control resulted in a doubling of hypoglycaemic episodes during pregnancy. The proportion of preterm deliveries was reduced from 47% to 24%. The rate of caesarean sections was nearly constant (1971-1980: 38%, 1981-1988: 34%). The marked success of therapy was the decrease of perinatal mortality from 20.9% to 2.9%. The perinatal morbidity also diminished, as shown by the decreasing rates (30-90%) of foetopathy, macrosomy, respiratory distress syndrome, birth trauma, hypoglycaemia, hypocalcaemia and polycythaemia. The malformation rate, however, remained high (1971-1980 = 7%, 1981-1988 = 11%). The results demonstrate the necessity of a strict blood glucose control during pregnancy, beginning before the time of conception.

Adult↗
PubMed1990

Trehalose transport and metabolism in Escherichia coli.

Trehalose metabolism in Escherichia coli is complicated by the fact that cells grown at high osmolarity synthesize internal trehalose as an osmoprotectant, independent of the carbon source, although trehalose can serve as a carbon source at both high and low osmolarity. The elucidation of the pathway of trehalose metabolism was facilitated by the isolation of mutants defective in the genes encoding transport proteins and degradative enzymes. The analysis of the phenotypes of these mutants and of the reactions catalyzed by the enzymes in vitro allowed the formulation of the degradative pathway at low osmolarity. Thus, trehalose utilization begins with phosphotransferase (IITre/IIIGlc)-mediated uptake delivering trehalose-6-phosphate to the cytoplasm. It continues with hydrolysis to trehalose and proceeds by splitting trehalose, releasing one glucose residue with the simultaneous transfer of the other to a polysaccharide acceptor. The enzyme catalyzing this reaction was named amylotrehalase. Amylotrehalase and EIITre were induced by trehalose in the medium but not at high osmolarity. treC and treB encoding these two enzymes mapped at 96.5 min on the E. coli linkage map but were not located in the same operon. Use of a mutation in trehalose-6-phosphate phosphatase allowed demonstration of the phosphoenolpyruvate- and IITre-dependent in vitro phosphorylation of trehalose. The phenotype of this mutant indicated that trehalose-6-phosphate is the effective in vivo inducer of the system.

Biological Transport↗
PubMed1990

Noninvasive and invasive diagnosis of a huge congenital aneurysm of the left atrium: a case report.

An intrapericardial aneurysm of the left atrium in a twenty-eight-year old asymptomatic woman is reported. The aneurysm was diagnosed by two-dimensional echocardiography and the specific intraaneurysmatic flow pattern was described by color blood flow imaging. To the authors' knowledge such a noninvasive diagnosis of a left atrial aneurysm has never been reported in the literature before. The diagnosis was confirmed by angiocardiography. The aneurysm was successfully resected. The patient was discharged without medication and continues to do well.

Adult↗
PubMed1990

Continuous induction of unscheduled DNA synthesis by gamma irradiation.

The induction of DNA-synthesis in non-S-phase cells is a very sensitive measure of a preceding damage of DNA. Usually, in an in vivo-in vitro test (treatment of an animal, incorporation of H3-thymidine in a cell suspension) the damaging of DNA takes place hours to days before the evaluation. In this case, the time course of the UDS-induction after a single dose of 1 Gy gamma irradiation was observed over a long period of time (21 months). C57 black mice served as test animals. In an age of about 80 days they were irradiated and the induction of unscheduled DNA synthesis was measured at ten time intervals during the whole life-span of the animals. Although the repair in this gamma radiation damage in DNA is a very quick process--with centrifugation in alkaline sucrose a half-life of some minutes is found--an induction of unscheduled DNA synthesis could be seen at the irradiated animals until the end of their life (640 days). The reason for this could be permanent disorders in cellular regulation caused by the gamma irradiation.

Animals↗
PubMed1990

Ketanserin prevents early restenosis following percutaneous transluminal coronary angioplasty.

In the treatment of coronary artery stenoses restenosis represents the main problem in 25-35% of cases following successful percutaneous transluminal coronary angioplasty (PTCA). In the present trial the effect of the 5HT2-serotonergic receptor antagonist ketanserin on the rate of restenosis after 24 h ('early restenosis') or 4-9 months ('late restenosis') was investigated. Preliminary studies demonstrated that ketanserin infused at the dose of 0.1 mg/min inhibited platelet aggregation without evidence of side effects. In the restenosis study, 43 patients (37 males, 6 females; mean 55 years) were randomized into two groups. After PTCA, 22 patients were treated with conventional therapy (group A), whereas 21 received additionally ketanserin (0.1 mg/min for 24 h, group B). The angiograms (prior to, after, 24 h after, and 4-9 months after PTCA) were examined in a blind manner using a computer-based quantitative angiographic system. After 24 h, 3 patients of group A, but none of group B showed restenosis (more than 50% decrease in diameter stenosis). In total, the diameter at the site of stenosis prior to PTCA decreased by 11% in the controls, but remained unchanged in the ketanserin-treated patients. After 4-9 months, 26% of group A (5 out of 19 patients examined) and 22% of the controls (4 out of 18 patients examined) developed restenosis of more than 50%; there was no statistical difference in the degree of residual stenosis between both groups. These findings suggest that a 24-hour infusion of ketanserin following PTCA may prevent early restenosis, but does not influence the incidence of late restenosis.

Adenosine Diphosphate↗
PubMed1990

201Tl myocardial SPECT and beta-endorphin levels in patients with suspected silent ischemia.

Today silent myocardial ischemia (SMI) is a well-recognized phenomenon. However, in the absence of clinical signs suggesting coronary artery disease (CAD), a streamlined diagnostic approach for precise clarification has proved to be difficult. Sensitivity and specificity of ergometric results are rather poor in symptom-free patients. Thus the question arises, whether the necessity of coronary angiography can be established more precisely by 201Tl myocardial SPECT in these patients. Treadmill exercise according to the Bruce protocol, 201Tl myocardial SPECT and coronary angiography were performed in a total of 106 patients with suspected SMI. In group I (high probability of ischemia; n = 46), reversible defects detected by SPECT correlated well with significant stenoses and irreversible defects with subtotal stenoses or complete occlusions. SPECT sensitivity in the detection of ischemia was 91%, its specificity 96%. In group II (low probability of ischemia; n = 60), SPECT sensitivity was as high as in group I (94%) but due to a high number of false-positive results (e.g. cardiomyopathy) specificity was only 75%. However, SPECT was superior to exercise ECG (sensitivity 70%; specificity 56%) in the detection of SMI. In addition, beta-endorphin levels were determined in 180 healthy subjects, 37 patients with symptomatic CAD and in 34 patients with SMI before and during maximum exercise. Exercise values in patients with SMI were significantly higher than in healthy subjects or in patients with symptomatic CAD.

Adult↗
PubMed1990

[A 58-year-old woman with unstable angina pectoris and restenosis after PTCA: successful therapy with ketanserin].

This case report describes a 58-year-old female suffering from unstable angina pectoris showing two-stem disease with occlusion of the left anterior descending artery at angiography. Due to continuous symptoms and ECG-deviations, percutaneous transluminal coronary angioplasty of the occlusion was performed twice with primary success. However, acute re-occlusion with angina and ECG-changes developed after 6 and 2 h, respectively. For technical reasons, immediate bypass surgery was impossible and thus, patient underwent a third dilatation followed by infusion of ketanserin (0.1 mg/min), a S2-serotonergic receptor antagonist, for 24 h. During this period, patient was without complaints and showed normal ECG. Hematocrit fell and viscosity as well as elasticity improved markedly by ketanserin. Renewed angina and ECG-deviations developed 2 h after discontinuation of ketanserin therapy and patient had to undergo coronary artery bypass grafting.

Angina, Unstable↗
PubMed1990

Serum selenium levels in distinct manifestations of coronary artery disease.

The trace element selenium plays an important role in the oxidation of lipids and is therefore closely associated with atherosclerosis. In a series of 49 unselected male patients having undergone coronary angiography, the serum selenium level was determined using flameless atomic absorption spectrometry (Zeeman technique), and compared to a standard (Seronorm; Nycomed). In the whole series the serum selenium levels were markedly decreased with no significant difference between patients with or without coronary artery disease. The severity of the coronary artery disease (CAD) did not correlate with the selenium level. However, patients with prior myocardial infarction had a significant higher selenium level than those without. Thus, the level of selenium does not appear to be a marker or a risk factor for coronary artery disease.

Aged↗
PubMed1989

[Tl-201 myocardial SPECT in silent myocardial ischemia and angiographically proven coronary heart disease].

Silent myocardial ischemia is defined as true myocardial ischemia without angina pectoris in patients with angiographically detected coronary artery disease. In this study 52 patients (46 male, 8 female: mean age 53 years) with a pathological exercise test but no symptoms were investigated. They showed stenosis of 75% or more of the diameter in at least one coronary segment on angiography. Prior to or after catheterization (within 14 days) Tl-201 SPECT was done and evaluated independently of angiography. A clear correlation between angiographically confirmed stenosis and reversible perfusion defects with Tl-201 SPECT was established (62 out of 76 lesions). Furthermore, there was a significant relation between angiographically detected subtotal or total occlusions of coronary vessels and irreversible perfusion defects using Tl-201 SPECT (35 in 44 lesions) (p less than 0.001). In patients with ST depression but without angina pectoris during the exercise test, the Tl-201 SPECT is highly suited to determine the hemodynamic effect of coronary stenoses.

Angina Pectoris↗
PubMed1989

[Management of acute intrathoracic aortic dissection].

At the intensive care station of the Internal Medicine Department, University Clinic Graz, all patients admitted were promptly and carefully examined in case of suspected acute intrathoracic aortic dissection and immediately treated. In 1987 a total of 4446 patients were referred to this CCU, 893 suffered from acute thoracic pain. In 21 patients of the latter a clinical suspicion of aortic dissection was observed. In 9 patients of these, diagnosis could be established within 5 hours by echocardiography, CT and angiography. 11 patients had no dissection while one positive finding could only be determined by postmortem exam. Retrospectively, these figures for 1982 were 3908 admitted patients, 790 suffering from acute thoracic pain of which only 5 showed suspected dissection. In 3 cases dissection could be confirmed using the same diagnostic procedures, but 2 were without finding. Further 3 patients out of the total series were affected with dissection which could only be determined postmortem. Out of the 9 patients with positive diagnosis, 6 showed Typ I, 1 Typ II and 2 Typ III dissection according to DeBakey (8m, 1f, range 46-78 years). 2 patients underwent surgery immediately after diagnosis, 1 after 12 hours, while 4 cases were conservatively treated. These 7 patients have survived by controlled hypotension up to now (10 to 22 months). Two patients died 2 and 10 hours, respectively, after admission with positive diagnosis. In spite of the severity of this disease prompt and efficient diagnosis and rapid therapeutic management are the key to survival.

Aged↗
PubMed1989

Differentiation of Al3+ and Al species in environmental samples by isotachophoresis.

An isotachophoretic method for the determination of free [Al(H2O)6]3+ ions in different aluminium salt solutions was developed. The electrolyte system consists of 0.01 M sodium acetate (leading system) and 0.01 M tris(hydroxymethyl)amino-methane (terminating system). Separation was effected with a precapillary tube (diameter 0.05 cm) followed by a main capillary tube of length 20 cm and of smaller cross-section. The detection limit for [Al(H2O)6]3+ ions was 0.05 mg/l. The method was applied to the determination of free Al3+ ions ([Al(H2O)6]3+) in soil leachates and aqueous soil extracts.

Acid Rain↗
PubMed1989

[Redilatation with the trefoil balloon catheter in 2 patients with a high degree of aortic stenosis].

Percutaneous transluminal balloon valvuloplasty (PTBV) is successfully applied in the treatment of calcified aortic stenosis. However, results following redilatation have not yet been dealt with in the literature. This method was successfully used in two patients (62a m/70a f) suffering from severe sclerotic aortic stenoses. Redilatation was undertaken in the first case after one month and after four in the second. A second redilatation by balloon catheter was done upon request of the patients after a further nine months. Following this third dilatation both patients suffered from femoral thrombosis which was treated surgically in the second case, while in the first local thrombolysis was done. In the management of the first patient valve replacement had to be performed four months after the last dilatation due to renewed complaints, while the second patient showed no evidence of recurrence within three months after the last dilatation.

Aged↗
PubMed1989

Stereoselective hemodynamic effects of (R)-and (S)-propranolol in man.

In a randomized, double-blind, placebo-controlled, cross-over study 24 healthy volunteers were examined before and 2 h after oral administration of 80 mg (R,S)-, 40 mg (R)- and 40 mg (S)-propranolol.HCl; 8 of them received placebo in an additional run. During exercise on a bicycle ergometer and a rest period the rate pressure product was decreased by 80 mg (R,S)-propranolol.HCl (-32.8% p less than 0.0001) and 40 mg (S)-propranolol.HCl (-32.3%; p less than 0.0001), whereas 40 mg (R)-propranolol.HCl as well as placebo showed no effect. Corresponding binding inhibition experiments using (-)-(125I)iodocyanopindolol in a sarcolemma-enriched cardiac membrane preparation yielded a eudismic ratio of 179 for (S)- over (R)-propranolol. 2 h after oral application, stereospecific HPLC analysis revealed different individual concentrations in plasma of (R)- 22.3 +/- 21.7 ng/ml) and (S)-propranolol (30.4 +/- 26.9 ng/ml) when 80 mg of (R,S)-propranolol.HCl was administered. The plasma levels were similar when 40 mg of the pure enantiomer of (R)- (22.7 +/- 20.3 ng/ml) or (S)-propranolol.HCl (28.7 +/- 22.5 ng/ml) was applied. (R)- and (S)-propranolol are two substances with different pharmacodynamic and pharmacokinetic properties. As there are methods available to produce the optically pure enantiomers, they should be used rather than the racemic mixture.

Adult↗