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Biomedical subjects

T Meinertz

Publications and source records attributed to T Meinertz.

At least 379 records · Page 21Linked to original sources
PubMed1979

Pharmacokinetics of azapropazone following single oral and intravenous doses.

The pharmacokinetics of azapropazone (Prolixan) was studied in 7 healthy volunters following single oral and i.v. doses of 600 mg. After i.v. injection plasma concentration declined biexponentially with time. The half-life of the beta-phase was 13.6 +/- 2.6 h (mean +/- SD), the apparent volume of distribution 11.9 +/- 3.5 l, and the total clearance 10.1 +/- 2.1 ml . min-1. Following oral administration peak plasma concentrations occurred between 3 and 6 h and declined with a beta-phase half-life of 14.3 +/- 2.8 h. The binding of azapropazone to plasma proteins was high (ranging from 99.52 to 99.67% at a total plasma concentration of 75 micrograms/ml). The bioavailability of azapropazone when administered as capsules was 83 +/- 19%.

Administration, Oral↗
PubMed1978

The positive inotropic effect of phenylephrine in the presence of propranolol. Increase in time to peak force and in relaxation time without increase in c-AMP.

The effects of phenylephrine on the shape of the contraction curve and on the cyclic adenosine 3',5'-monophosphate (c-AMP) content were studied in electrically driven (frequency 0.2 Hz) cat papillary muscles. All experiments were done in the presence of 1 micron propranolol in order to minimize interference from beta-adrenoceptors. 1. Phenylephrine increased the force of contraction in a concentration-dependent manner. Maximal effects (about 200% of control) occurred at 30 micron phenylephrine. 2. The positive inotropic effect (PIE) of phenylephrine was antagonized by phentolamine. Phentolamine, 5 micron, produced a parallel shift of the concentration-response curve for the PIE of phenylephrine by about two log units to the right. 3. The PIE of 30 micron phenylephrine occurred without any detectable increase in the c-AMP levels of the preparations. 4. The PIE of 30 micron phenylephrine developed about three times more slowly than the PIE of an equieffective concentration of isoprenaline. 5. The PIE of phenylephrine was accompanied by significant, concentration-dependent increases in both time to peak force and relaxation time. 6. It is concluded that the PIE of phenylephrine in the presence of propranolol is mediated mainly by a stimulation of alpha-adrenoceptors. It is unlikely to be related to an increase in c-AMP. With respect to time course and influence on the shape of the contraction curve it is qualitatively different from the effects of beta-adrenoceptor stimulation. These data are taken to support the hypothesis that the mechanical effects of alpha- and beta-adrenoceptor stimulating agents on the heart are produced by different mechanisms.

Adrenergic beta-Antagonists↗
PubMed1978

Diagnosis of dissecting aortic aneurysm with suprasternal echocardiography.

A 33 year old woman with Marfan's syndrome and aortic root dissection was studied with precordial and suprasternal echocardiography. The precordial approach revealed some typical features of aortic root dissection. With suprasternal echocardiography it was possible to visualize the characteristic diagnostic feature of this disease: within the aortic lumen an m-shaped pattern--the aortic intimal flap--moving downward to the posterior aortic wall during systole. The diagnosis was confirmed with aortic cineangiography and intraoperative findings. Thus, suprasternal echocardiography can be a useful method of detecting aortic root dissection, especially in patients with aortic arch dissection alone.

Adult↗
PubMed1978

Enhanced elimination of warfarin during treatment with cholestyramine.

1 The elimination and anticoagulant activity of a single intravenous dose of warfarin (1.0-1.2 mg/kg) without and with concomitant cholestyramine treatment (about 4 g three times daily) was studied in five healthy male subjects. 2 Cholestyramine treatment decreased the biological half-life of plasma warfarin (from a mean value of 2 days -1.3 days) and increased the total clearance of this drug (from a mean value of 37 ml kg-1 day-1--53 ml kg--1 day--1). 3 The total anticoagulant effect per dose of warfarin, as measured by the area under the effect v time curve, was also reduced by cholestyramine (average reduction of about 25%). 4 Warfarin possibly undergoes enterohepatic recycling in man which can be interrupted by cholestyramine.

Adult↗
PubMed1978

Positive inotropic but no relaxant effects of phenylephrine in cat papillary muscle.

The effect of phenylephrine (30 micron) in the presence of propranolol (1 micron) on electrically induced isometric twitches and on KCl-contractures was studied in papillary muscles from reserpine-pretreated cats at 25 degrees C. Under these conditions phenylephrine has previously been shown to act solely via alpha-adrenoceptors and not to increase c-AMP. Phenylephrine increased force of contraction, time to peak tension and relaxation time. Contracture tension remained unaffected. These data indicate that the stimulation of cardiac alpha-adrenoceptors, in contrast to beta-adrenergic stimulation, does not lead to so-called relaxant effects. This qualitative difference between the two responses is probably due to the different capacity of both stimuli to increase c-AMP.

Animals↗
PubMed1978

[The facial muscles of insectivora. I. Erinaceus europaeus and Talpa europaea].

This investigation includes the area of n. facialis in Erinaceus europaeus and Talpa europaea. It is indicated that the topography of muscles diverges considerably from the equally conditions in Rodentia, Carnivora, and Ungulata. The dorsal length musculature thus is an almost undivided mass of muscles in the 2 investigated species as also the laterally and ventrally situated musculature at certain points diverges from the conditions within other above mentioned animal groups.

Animals↗