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Biomedical subjects

T Brecht

Publications and source records attributed to T Brecht.

At least 19 recordsLinked to original sources
PubMed1991

Acute haemodynamic effects of i.v. nitrendipine in healthy subjects.

The haemodynamic effects of an i.v. infusion of 2 mg nitrendipine have been studied in six healthy volunteers. Nitrendipine significantly decreased the systolic (-8.3%) diastolic (-19.9%) and mean arterial (-11.6%) blood pressures and the peripheral vascular resistance (-57.8%), and significantly increased leg blood flow (+128%). Stroke volume did not change. Due to the increase in heart rate (+28.5%), the cardiac output (2.8.2%) rose significantly. The haemodynamic effects were closely related to the serum nitrendipine concentration. The sigmoidal Emax-model was appropriate to describe the data. Pronounced interindividual differences in the serum nitrendipine concentrations required to elicit 50% of the maximum haemodynamic effect (EC50) were observed. The EC50 for the increase in leg blood flow ranged from 2.9 to 30.9 ng/ml and for the reduction in peripheral vascular resistance from 2.1 to 25.7 ng/ml. Interindividual differences in EC50 values were less pronounced if based on unbound serum nitrendipine levels. The fraction of nitrendipine not bound to serum proteins showed a three-fold difference between subjects, with free fractions ranging from 0.011 to 0.036. The unbound EC50 values for the increase in leg blood flow varied between 0.06 and 0.44 ng/ml and for the reduction in peripheral vascular resistance from 0.07 to 0.35 ng/ml. Based on the serum concentrations associated with comparable haemodynamic effects nitrendipine was at least three-times more potent than nifedipine.

Adult↗
PubMed1987

Effects of misoprostol on human circulation.

Prostaglandins (PGs) of the E-type are potent vasodilators in most species and in most vascular beds. However, vasoconstrictor effects of PGEs have also been noted at selected sites. This study examined the effects of misoprostol, a PGE1 analog with antiulcer activity, on the human cardiovascular system. Twenty healthy subjects participated in this double-blind, placebo-controlled, parallel group study. Following a 12 hour fast, heart rate, arterial blood pressure, light reflex plethysmography of the finger, resting blood flow volume in the lower arm and leg and peripheral vascular resistance were measured at 10 min. intervals for 1 hour prior to drug administration, to permit calculating baseline values. Misoprostol (400 mcg) or its matching placebo were administered orally, and the measurements were repeated at 10 min. intervals over the next 2 hours. A decrease in leg blood flow volume and a corresponding increase in leg peripheral vascular resistance were noted in the misoprostol group. A statistically significant decrease in heart rate between the two treatment groups was also noted. These small changes were not considered to be of clinical importance. No adverse experiences were reported. In conclusion, a single dose of misoprostol (400 mcg) has no clinically significant vasoconstrictive or vasodilative properties in man.

Alprostadil↗
PubMed1986

[Sonographic diagnosis of arterial occlusive disease].

In 32 patients presenting symptoms of arterial occlusive disease, 50 lower limbs were examined both by ultrasonography and angiography (DSA). Sonography was performed using a 5.0 MHz real-time scanner; common femoral, superficial femoral and deep femoral arteries were visualized continuously in whole length. In 84% both the results from sonography and digital subtraction angiography verified or excluded arterial occlusion. Since lack of pulsation is the ultrasonic criterion of occlusion, real-time ultrasound does not differentiate between haemodynamically effective high-grade stenosis and total occlusion.

Aged↗
PubMed1986

[Pharmacodynamics of etilfrine pivilate in the orthostatic syndrome].

Etilefrine pivalate is synthesized by esterification of etilefrine with pivalic acid anhydride. The pharmacodynamics were investigated in 8 subjects suffering from the orthostatic syndrome. Cardiocirculatory parameters were measured in the lying and standing position for 3 h after the oral ingestion of 30 mg of etilefrine pivalate. In the supine position only minor effects on the blood pressure were seen. In three subjects with true orthostatic syndrome the systolic blood pressure was increased from 10 to 60 min after medication. Up to 30 min positive inotropic effects were seen. During 70 degree tilt etilefrine pivalate could stabilize the blood pressure 20 min after medication, the pathological increase in heart rate was reduced. In non-orthostatic patients positive inotropic effects were seen in the lying position only. Blood pressure and heart rate were not influenced in the supine position.

Blood Pressure↗
PubMed1985

Circulation parameters during intravenous and intra-arterial administration of increasing doses of prostaglandin E1 in healthy subjects.

Increasing doses of prostaglandin E1 given intravenously do not influence the hemodynamic parameters up to a dosage of 1500 ng/min. Intra-arterial administration of a mixture of nucleotides and nucleosides in therapeutic doses induces an increase in the blood flow volume at rest of up to 400%. With dosages of 20 ng/min and more, intra-arterial administration of PGE1 induces only a slight increase in the blood flow volume of the extremity under treatment. The therapeutic effects of the substance, therefore, are probably more due to other mechanisms of action than to hemodynamic effects.

Adult↗
PubMed1985

The effect of dextro-, levo-, and racemic verapamil on atrioventricular conduction in humans.

To study the dromotropic effects of dextro(D)- and levo(L)-verapamil on atrioventricular (AV) conduction in humans, we investigated the prolongation of the PR interval following intravenous administrations of each isomer and racemic preparation (D, 5, 25, and 50 mg; L, 5, 7.5, and 10 mg; racemic, 10 mg). The plasma drug concentration-effect relationship was analyzed by log-linear regression and the sigmoidal Emax model. The sigmoidal Emax model provided a significantly better fit for the data than log-linear regression (p less than 0.01). Maximum drug effect (Emax) and plasma drug concentration associated with 50% Emax (EC50) were calculated by means of the Emax model. The dromotropic potency of each isomer was assessed in terms of EC50 and the drug concentration associated with a 10% PR prolongation from the basal level calculated by the Emax model. The results demonstrated that L-verapamil was 10 and 18 times more potent than D-verapamil in terms of EC50 (D, 188.9 +/- 108.4 ng/ml; L, 17.7 +/- 11.3 ng/ml; p less than 0.05) and drug concentration associated with 10% PR prolongation (D, 166.6 +/- 48.1 ng/ml; L, 9.1 +/- 2.8 ng/ml; p less than 0.01), respectively. A stereospecific difference in plasma protein binding was observed (D, 93.7 +/- 2.2%; L, 88.5 +/- 1.6%; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

[Effect of digitalis on hemodynamics during rest in patients with arterial occlusive diseases, stage II, without cardiac insufficiency].

In 6 patients without clinical symptoms of myocardia insufficiency and with stage II occlusive disease of the femoral artery, blood flow volume at rest, arterial blood pressure and heart rate were measured before, during and for two hours after an iv. infusion of 1.0 mg desacetyl-lanatoside. Blood flow at rest decreased by 23% and peripheral vascular resistance increased by 34%. The increase in the blood pressure amplitude was compensated by a decrease in heart rate. The mechanism of action is discussed. It is concluded that patients suffering from stage II arterial occlusive disease do not benefit at rest from the prophylactic administration of digitalis.

Aged↗
PubMed1981

Therapeutic effects of intraarterial phentolamine in "Raynaud's syndrome".

Five patients suffering from "Raynaud's syndrome" were studied as regards the effects of increasing doses of intraarterially administered phentolamine on the blood flow to the digital arteries. Upon angiography they had shown multiple occlusions of their digital arteries. Venous occlusive plethysmography of the forearm, volume pulse amplitude of a finger tip of treated and untreated extremity, respectively, intraarterial pressure in the brachial artery and ECG lead II have been monitored continuously. The blockade of the alpha-adrenoceptors by phentolamine resulted in a favourable effect upon the accompanying functional component: The volume pulse amplitude of and the blood flow to the treated extremity increased considerably, without significant changes in the other hemodynamic parameters upon administration of doses up to 0.5 mg of phentolamine. A dose of 0.5 to 1.0 mg of phentolamine seems to be the optimum, higher doses yielding no better results. The effective blockade of the alpha-adrenoceptors could be demonstrated by the influence on the arterial blood pressure during a Valsalva maneuver, on the venous reflex response, and the diminished effectiveness of noradrenaline in the treated extremity.

Adult↗
PubMed1980

[Changes in the arteries in the hand and fingers due to vinyl chloride exposure (author's transl)].

The results of angiography of the hand in workers in the vinyl chloride industry are described. Amongst 93 patients, there were 19 on whom angiograms of the hand were performed because of Raynaud-like changes, pain or other pathological findings. All patients examined by angiography showed abnormalities in the vessels in the hands and fingers of varying severity. Vascular occlusions (17 patients), stenoses (9 patients) and thread-like narrowing of the digital arteries (6 patients) with the development of a collateral circulation, were prominent findings. In addition there was elongation and tortuosity of the digital arteries (14 patients) which were regarded as cirsoid aneurysms. The angiographic findings have been correlated with the known histological changes.

Adult↗
PubMed1979

[Fibrinolytic treatment with urokinase in older phlebothrombosis (author's transl)].

28 patients with 1 to 6 week old occlusions of the femoral and/or iliac veins as well as the subclavian veins were treated with a standardised urokinase-heparin-scheme. The fibrinolytic therapy was generally performed over a period of 7 to 14 days. In 2 patients, the 1 and 6 weeks respectively old thromboses of the iliac, femoral and tibial veins, and in 4 patients the 5 to 16 days old thromboses of the subclavian veins could be dissolved completely, 16 patients showed clinically and phlebographically a substantial amelioration. In 6 patients no marked success was found.

Adult↗
PubMed1979

[Computer tomography in the diagnosis of aortic aneurysms (author's transl)].

The paper describes the diagnosis of ten thoracic, 20 abdominal and three peripheral arterial aneurysms by computer tomography. This permits a definite diagnosis by a non-invasive method, it defines the extent of the aneurysm and the amount of thrombus in the aneurysm; it permits recognition of a leak and is painless and without risk and can be performed rapidly. Morever, computer tomography provides an accurate control of growth of the aneurysm. In some cases a dissection can be recognised. The use of adequate quantities of intravenous contrast medium prevents any possibility of an incorrect diagnosis. The extent and density of the aneurysms, their lumina, clot and wall thickness, as determined by computer tomography are described. The values are compared with the aortic diameters of patients with normal vessels. The advantages of the method, compared with other procedures, are discussed and its role in the diagnosis of aortic and peripheral arterial aneurysms is described.

Aged↗
PubMed1978

[Vascular effects of digitalis in human extremities (author's transl)].

The effect of lanatosid C on the peripheral vascular system was studied in a randomized double-blind cross-over study. 1 mg lanatosid C in saline or a corresponding volume of saline were applied intravenously for 30 min to healthy subjects. A significant drop of 28% in blood flow and an increase of peripheral vascular resistence at rest of 44% during and after the application of the cardiac glycoside could be seen while the placebo effect was minimal.

Adult↗