Search PubMed⌕ Search

Biomedical subjects

R Zimmermann

Publications and source records attributed to R Zimmermann.

At least 415 records · Page 23Linked to original sources
PubMed1988

Increase in calcium sensitivity of cardiac myofibrils contributes to the cardiotonic action of sulmazole.

The aim of this study was to investigate whether increasing calcium sensitivity of myofibrils plays a role in the positive inotropic activity of the cardiotonic agent sulmazole. We studied the effects of the stereoisomers of sulmazole on cardiac contractility in vivo and in vitro, arterial blood pressure, cardiac (Na-K)ATPase activity, cAMP/cGMP-phosphodiesterase activity of cardiac and smooth muscle tissue and calcium sensitivity of skinned myocardial fibres. Both stereoisomers of sulmazole were equipotent vasodilators in vivo and this can be explained by their equipotent cAMP- and cGMP-phosphodiesterase inhibitory activities in smooth muscle tissue. However, (+)sulmazole was a much stronger positive inotropic agent than (-)sulmazole in vivo and in vitro. This difference in inotropic activity cannot be explained by cAMP- or cGMP-phosphodiesterase inhibition or (Na-K)ATPase inhibition in cardiac tissue. Only (+)sulmazole produced a dose-dependent increase in calcium sensitivity of skinned myocardial fibres. Therefore, the calcium sensitizing effect on myofibrils evoked by (+)sulmazole might be responsible for the difference in inotropic activity observed between the stereoisomers of sulmazole.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

[Childbirth in 2 patients with congenital analgesia].

Pregnancy and labour in two cases of congenital analgesia are reported. Not only was there total absence of labour pains but also no perception of uterine contractions. In both cases the women did not notice the onset of labour till the moment of spontaneous rupture of the membranes. Due to the absence of bearing down efforts, expulsion ceased for several hours in the second stage; nevertheless, delivery followed spontaneously. As the patient is unaware of labour, fetal asphyxia may occur during the second stage if the child is not under technical control. Stillborn children have been reported. For this reason we recommend programmed birth in cases of congenital analgesia.

Adult↗
PubMed1988

[Initial experiences with the effect of chronic intermittent electromyostimulation in patients with hyperlipoproteinemias and arterial circulatory disorders].

Metabolic and clinical effects of an original electromyostimulation are explained which induces muscle contractions by changes of the field intensity in the region of microseconds in forms of delivered impulse groups. On account of the good local compatibility due to optimal irritation parameters the muscle stimulator was suitable for a long-term application. Examinations on 23 patients with hyperlipoproteinaemia and mixed HLP (n = 15) and primary hypercholesterolaemia (n = 8) after a 2 times 2 hours/day mutual stimulation of the femoral musculature in a frequency of 2 s-1 lasting four weeks yielded a significant decrease of the triglyceride and cholesterol concentrations as well as an increase of the HDL-cholesterol in mixed HLP-forms. Examinations not yet finished refer to an increase of the extrahepatic activity of the postheparin-lipoprotein lipase and to the concentration of the HDL2-cholesterol. An influence of the hypercholesterolaemia IIa could not be made evident. An electrostimulation performed for 3 months in 8 patients with obliterating arteriosclerosis resulted in a more sufficient collateral blood supply of the legs. The long-term use of the device was unobjectionable also under ambulatory conditions. On the basis of additionally gathered experiences further indications of an electrostimulation were cited. Possible variations of the electrostimulation irritation parameters might make accessible further fields for the preventive and curative medicine.

Adult↗
PubMed1988

Import of honeybee prepromelittin into the endoplasmic reticulum: energy requirements for membrane insertion.

The import of small precursor proteins, derived from the honeybee secretory protein prepromelittin, into dog pancreas microsomes is independent of signal recognition particle (SRP) and docking protein, but requires that charged amino acids at the amino terminus of the mature part are counterbalanced by amino acids with the opposite charge at the carboxy terminus. The import pathway of such precursor proteins was resolved into two sequential steps: (i) binding of precursors to microsomes, and (ii) insertion of precursors into the membrane. Formation of an intramolecular disulfide bridge within the mature part of these precursor proteins allowed association of the oxidized precursors with the microsomal membrane but reversibly inhibited their membrane insertion. Furthermore, membrane insertion was inhibited by ATP depletion. Different prepromelittin derivatives were found to depend on ATP to varying degrees. We conclude that insertion of prepromelittin-derived precursor proteins into microsomal membranes involves a competent conformation of the precursor proteins and that, in general, this is accomplished with the help of both a cytoplasmic component and ATP.

Adenosine Triphosphate↗
PubMed1988

Seventy-kilodalton heat shock proteins and an additional component from reticulocyte lysate stimulate import of M13 procoat protein into microsomes.

Processing of M13 procoat protein, synthesized in a bacterial cell-free extract, to transmembrane coat protein by dog pancreas microsomes is stimulated by a system which is present in rabbit reticulocytes and depends on nucleoside triphosphates. This system consists of (at least) two components which act synergistically: members of the 70-kd heat shock protein family and (at least) one additional component. This component depends on ATP (or GTP) for its action.

Adenosine Triphosphate↗
PubMed1988

Effect of dried garlic on blood coagulation, fibrinolysis, platelet aggregation and serum cholesterol levels in patients with hyperlipoproteinemia.

The effects of intake of dried garlic on blood coagulation, fibrinolysis, platelet aggregation, serum cholesterol levels, and blood pressure were studied in 20 patients with hyperlipoproteinemia over a period of four weeks. Fibrinogen and fibrinopeptide A significantly decreased by 10%. Streptokinase activated plasminogen and fibrinopeptide B beta 15-42 significantly increased by about 10%. Serum cholesterol levels significantly decreased by 10%. Systolic and diastolic blood pressure decreased. ADP and collagen induced platelet aggregation were not influenced.

Adult↗
PubMed1988

Active movements of the cuticular plate induce sensory hair motion in mammalian outer hair cells.

It has been suggested that active motor capacities may explain the high sensitivity and sharp tuning of auditory transduction in the mammalian cochlea. Recently, slow and fast motile responses of isolated outer hair cells (OHCs) have been demonstrated. These consist of reversible length changes in the cylindrical cell body. Here we show that isolated OHCs are also capable of slow and fast movements of the cuticular plate (CP) which cause passive displacements of the stereocilia. The molecular mechanisms that underlie the slow movements appear to reside in the highly organized actomyosin cytoskeleton in the CP. Additional, fast movements of the CP were observed in OHCs which were exposed to alternating electrical fields. These rapid mechanical events followed the electrical stimulus cycle-by-cycle, and unlike the slow movements, did not depend on the actomyosin skeleton in the CP. The fast motility of the CP and the attached stereocilia suggest an additional active mechanism which may contribute to the sensitivity and the sharp tuning of the cochlea near threshold. By controlling the operating point of the reticular lamina and of the hair bundles, the slow CP and stereociliary movements may influence basilar membrane homeostasis and temporary threshold shift at high sound pressure levels.

Adenosine Triphosphate↗
PubMed1988

Regional myocardial nitrogen-13 glutamate uptake in patients with coronary artery disease: inverse post-stress relation to thallium-201 uptake in ischemia.

The purpose of the present study was to evaluate the clinical significance of myocardial scintigraphy with nitrogen-13 (N-13) glutamate as a marker of myocardial metabolism. Within 2 weeks after cardiac catheterization, 25 patients with single vessel left anterior descending coronary artery disease underwent thallium-201 imaging (5 min and 3 h after injection) and N-13 glutamate scintigraphy (10 min after injection). Radionuclide studies were performed in the 30 degrees left anterior oblique projection after symptom-limited bicycle exercise, and regional tracer uptake was quantified by computer-assisted placement of regions of interest within the regions of myocardial activity. Poststenotic tracer uptake in the perfusion bed of the left anterior descending coronary artery (septum) was then normalized to the tracer uptake in the nondiseased left circumflex territory (posterolateral segments = 100%). In 14 patients with a history of previous myocardial infarction (Subgroup A), deficient poststenotic N-13 uptake correlated closely with thallium-201 uptake in both initial (r = 0.82, p less than 0.001) and redistribution (r = 0.74, p less than 0.01) scintigrams. By contrast, in 11 patients with no previous myocardial infarction and normal left ventricular function at rest (Subgroup B), initial uptake of both tracers was inverse: poststenotic N-13 glutamate uptake increased with decreasing thallium-201 uptake during exercise-induced ischemia (r = -0.64, p less than 0.05) and was closely correlated with the percent thallium-201 redistribution (r = 0.74, p less than 0.01). Thus, augmented accumulation of N-13 glutamate in reversibly ischemic (that is, viable) myocardium, and decreased uptake in myocardial scar tissue suggest the clinical usefulness of this metabolic tracer in the differentiation between viable (metabolically active) and irreversibly damaged myocardium.

Coronary Disease↗
PubMed1988

Noninvasive assessment of coronary artery bypass patency: determination of myocardial thallium-201 washout rates.

This prospective study was undertaken to investigate the response of thallium-201 washout rates to coronary artery bypass surgery. Thirty-four patients with coronary heart disease were studied before and after coronary artery bypass grafting, 27 patients with normal coronary arteries serving as controls. All patients underwent cardiac catheterization and thallium-201 serial imaging, including assessment of myocardial washout rates. Pre-operatively, thallium-201 washout rates yielded a considerably higher sensitivity in detection of coronary artery disease, without significant loss of specificity compared to qualitative evaluation of serial static thallium-201 scintigrams. Post-operatively, 50 of 57 segments supplied by a patent graft showed normal washout rates, while in 9 out of 11 segments an occlusion of the graft was indicated by decreased washout rates. Compared to pre- and post-operative qualitative interpretation of static thallium-201 images, the post-operative assessment of washout rates increased both sensitivity (82% vs. 64%) and specificity (88% vs. 77%) for the evaluation of bypass graft patency. Thus, quantitative assessment of thallium-201 washout rates improves the diagnostic reliability of noninvasive detection of myocardial ischaemia with regard to the evaluation of coronary artery bypass graft patency.

Coronary Artery Bypass↗
PubMed1988

Significance of thrombin-receptors of thrombocytes for the interaction of heparins and low-molecular-weight heparin in human whole blood clotting.

We describe in the present paper the results of the influence of normal and low-molecular-weight heparin on the interaction of human fibrinogen and thrombocytes in human whole blood cotting ex vivo. During the coagulation process sequential measurements of fibrinopeptide A reflect fibrin formation and determination of platelet factor 4 indicate activation of thrombocytes. The data show that low-molecular-weight heparin inhibits plasma thrombin generation in vivo for longer than normal heparin and it affects the fibrinogen platelet binding less. There is good evidence that a lonely factor Xa inhibition mediates this anticoagulant mechanism. Therefore, these data favor the hypothesis that antifactor Xa activity prevents indeed blood clotting.

Blood Coagulation↗
PubMed1988

Primary and secondary long-term prophylaxis of thromboembolism in outpatients with the low-molecular-weight heparin Kabi 2165.

Bleeding episodes and other side effects may complicate the treatment with oral anticoagulants. We report on the results of 66 patients who were treated with a low molecular weight heparin fraction for up to 19 months. The data of the study demonstrate the effective long-term anticoagulation with low-molecular-weight heparin and the reduced incidence of hemorrhages compared with conventional anticoagulants. Thus, low-molecular-weight heparin may be effectively and safely used for long-term anticoagulation in patients with bleeding problems on conventional anticoagulants.

Clinical Trials as Topic↗
PubMed1988

[Thrombolytic therapy of deep venous thrombosis with rt-PA].

Recombinant human tissue-type plasminogen activator (rt-PA) was given to seven patients with phlebographically documented deep vein thrombosis at a dose of 60-120 mg/day (0.71-1.76 mg/kg body weight/24 h) for 2 to 4 days. rt-PA induced evident recanalization in 6 of 7 cases. The lowest here used dose of 0.71 mg/kg/24 h was thrombolytical highly effective, but a dose of 1.4 mg/kg/24 h and over was accompanied by bleeding from venous puncture sites. Coagulation analysis showed no obvious decrease of fibrinogen, while euglobulin clot lysis time and thrombelastography demonstrated the systemic fibrinolytic activity. Thus, therapy with rt-PA may represent an alternative and effective therapeutic procedure in treatment of venous thrombosis. The initial results make a case for expanded investigational use of rt-PA in patients with deep vein thrombosis to clarify conceivable advantages of therapy with this fibrin selective thrombolytic agent.

Blood Coagulation Tests↗
PubMed1988

Dysfunctional uterine bleeding.

Abnormal uterine bleeding in the reproductive age, that is, dysfunctional uterine bleeding, is a very common symptom encountered in office gynecology. The judicious use of hysteroscopy to manage this medical entity adds a new dimension in handling this often perplexing problem. This article focuses mainly on abnormal uterine bleeding in the reproductive years because the use of hysteroscopy for this problem in the peri- or postmenopausal woman is less well defined.

Endoscopy↗