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Biomedical subjects

B Stanek

Publications and source records attributed to B Stanek.

70 records · Page 4Linked to original sources
PubMed1981

Cardiovascular effects of dihydroergotamine during epidural anaesthesia in dogs.

The haemodynamic changes during epidural anaesthesia and following the administration of dihydroergotamine (DHE; 10 micrograms/kg i.v.) were studied in 7 dogs (epidural group). Epidural anaesthesia was associated with reductions in mean arterial, mean pulmonary arterial and mean right atrial pressures. Femoral flow was increased by 119.9 +/- 35.0% and femoral resistance fell by 62.7 +/- 7.2%. All these changes were abolished by additional administration of DHE during epidural anaesthesia. In a second group of dogs (control group, n = 8) with intact innervation, i.e. without epidural block, DHE (10 micrograms/kg iv.) also decreased femoral flow and increased femoral resistance which, however, was significantly less pronounced ( p less than 0.01). It is concluded that DHE in epidural anaesthesia constricts arteriolar resistance vessels, mainly within the blocked areas.

Anesthesia, Epidural↗
PubMed1980

Plasma concentrations of noradrenaline and adrenaline and plasma renin activity during extradural blockade in dogs.

Anaesthetized dogs (pentobarbitone 25 mg kg-1 + 3 mg kg-1 h-1) with a Teflon catheter inserted to the femoral artery for pressure and heart rate measurement and blood sampling were studied. Extradural puncture was carried out at L7--S1 under x-ray control and 2% lignocaine (1 ml min-1) infused for approximately 10 min. During extradural block a decrease in arterial pressure was accompanied by a simultaneous decrease in plasma noradrenaline concentration (NA) and a compensatory increase in plasma renin activity (PRA), which became significant 15 min after commencing the block when the arterial pressure was at the minimum. Dihydroergotamine (DHE) led to a rapid reversal of the hypotension with no change in heart rate and a decrease in PRA. Hypovolaemia (blood loss 5 ml kg-1) was induced before and during block, respectively, in two further experimental groups. Increased NA and PRA were found under hypovolaemia without extradural block, but only PRA increased with hypovolaemia and a block. The effects of DHE in the later studies were comparable to those observed in the initial study.

Anesthesia, Epidural↗
PubMed1980

[Animal model for testing the influence of drugs on partially ischaemic and normal myocardial regions (author's transl)].

Blood flow was measured both in the circumflex and descending branch of the left coronary artery of anaesthetized dogs. Venous blood was sampled from the areas supplied by these vessels and arterial blood from the aorta for determination of oxygen-saturation, haemoglobin content, pCO2, glucose, lactate, and free fatty acids (FFA). The coronary blood flow in both branches, heart rate, aortic blood pressure, LVEDP and LVdp/dtmax were registered continuously. After taking control values, resting blood flow in the circumflex branch was mechanically reduced by 40% and the changes in haemodynamics and myocardial metabolism were measured 30 min thereafter. Heart rate, blood flow in the descending branch and LVEDP rose, whilst arterial blood pressure and LVdp/dt were not significantly changed. The partially ischaemic myocardium showed a decrease in lactate, FFA and oxygen uptake and CO2 release. The simultaneously determined metabolic parameters for the non-ischaemic region showed significant increases in lactate and oxygen uptake and CO2 and H-ion release. The overall balance (partially ischaemic and normal regions) showed a significant decrease in lactate and FFA uptake, which was, however, of very small magnitude. These results show that the antianginal action of drugs should not be assessed by determination of arterio-coronary venous balances for the whole heart, but for partially ischaemic and normal regions separately, as is possible in the presented experimental model. Moreover, sympathetic or direct stimulation can be used to stimulate increased effort of the heart such as occurs in angina pectoris.

Animals↗
PubMedDate not supplied

The effect of repeated intravenous and oral doses of molsidomine (N-carboxy-3-morpholino-sydnonimine-ethylester) on plasma renin activity and plasma catecholamine levels in conscious dogs.

The responses of plasma renin activity (PRA) and plasma catecholamine levels to molsidomine, administered both intravenously and orally, were investigated in conscious trained dogs. Intravenous administration of molsidomine at increasing dosage up to 0.4 mg/kg with a constant dose interval of 4 hours did not lead to a sustained increase in PRA. By contrast, a significant increase in PRA was still present after 4 hours on administration of 0.4 mg/kg molsidomine by the oral route. This longer-lasting increase in PRA following oral administration is discussed in relation to the conversion of molsidomine to an active metabolite in the liver. A reduction of dose interval to 3 hours or less led to a marked cumulative increase in PRA. It appears that substances acting via venous pooling lead to persistent activation of the renin angiotensin aldosterone system (RAA system), which counteracts its primary therapeutic effect. A slight increase in plasma noradrenaline levels was observed in response to repeated oral administration of 0.4 mg/kg molsidomine at a dose interval of 2 hours, indicating participation of the sympathetic nervous system in the counterregulatory process.

Animals↗