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Biomedical subjects

J Trap-Jensen

Publications and source records attributed to J Trap-Jensen.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effects of smoking on the heart and peripheral circulation.

Cigarette smoking increases heart rate, arterial blood pressure, and plasma catecholamine levels. In healthy subjects the increase in heart rate occurs in the absence of peripheral vasoconstriction. In the studies reported here, short-term beta-blockade increased peripheral vascular resistance during smoking, more so for the nonselective beta-blocker propranolol than for the beta 1-selective blocker atenolol. However, after 3 months of continuous treatment of hypertensive patients with beta-blockers, smoking produced similar increases in blood pressure for atenolol and propranolol. Smoking attenuated the beneficial blood pressure-lowering effect of beta-blockers. Short-term clinical studies with the nonselective alpha-inhibitor phentolamine have suggested that blockade of arteriolar alpha-receptors may eliminate the increase in blood pressure response to smoking. Treatment with alpha-inhibitors also increased coronary sinus blood flow in patients with atherosclerotic artery disease. For patients who smoke, alpha-inhibiting drugs may provide beneficial therapy for hypertension and other cardiovascular disorders.

Atenolol↗
PubMed1988

Acute unilateral obstruction of ureter. Disparity in divided renal function calculated from 131I-hippuran and 99mTc-DTPA renography.

Fifteen patients with acute unilateral obstruction of ureter and 30 control patients were studied with simultaneous 131I-Hippuran and 99mTc-DTPA gamma camera renography. In severe outflow obstruction the relative function of the obstructed kidney was higher when calculated with Hippuran than with DTPA. No difference was found in the control subjects. This means that the glomerular filtration rate of an obstructed kidney may be relatively more reduced than the renal blood flow. Therefore, measurement of the single kidney fraction of total glomerular filtration rate has to be calculated with a glomerular filtered tracer, e.g., 99mTc-DTPA.

Adult↗
PubMed1988

The effect of exercise on platelet beta-adrenoceptor function and platelet aggregation in healthy human volunteers.

UNLABELLED: Plasma levels of adrenaline and noradrenaline, platelet cyclic-AMP (cAMP) content, platelet aggregation, platelet release of beta-thromboglobulin, and platelet factor 4 and serum content of thromboxane B2(TXB2) and 6-keto-PGF1 alpha were measured in 12 healthy male volunteers (age 38-72, mean 54.2 years) who were tested at rest and immediately after five min light cycle exercise. The plasma levels of adrenaline and noradrenaline increased significantly after exercise (P less than 0.01). The platelet cAMP level was not changed by exercise. The functional capacity of platelet beta-adrenoceptors, determined as cAMP production after beta-adrenoceptor stimulation in vitro, decreased highly significantly after exercise in all 12 volunteers (P less than 0.01). No alteration was observed in platelet aggregation induced by adrenaline or in platelet release of beta-thromboglobulin or platelet factor 4. No change was observed in the serum levels of TXB2 and 6-keto-PGF1 alpha. IN CONCLUSION: light cycle exercise results in a decreased functional capacity of platelet beta-adrenoceptors, but has no effect on platelet aggregation or platelet release. This might indicate a concomitant and equal decreased functional capacity of platelet alpha-adrenoceptors.

Adult↗
PubMed1988

Long term haemodynamic effects of pinacidil and hydralazine in arterial hypertension.

Eight patients with a diastolic blood pressure greater than or equal to 100mm Hg when treated with a diuretic and a beta-blocker participated in a randomised crossover study comparing the haemodynamic effects of adjunctive therapy with pinacidil or hydralazine. The vasodilator dose was increased until the diastolic blood pressure was less than 90mm Hg or the maximum dosage, hydralazine 100mg twice daily, or pinacidil 50mg twice daily, was reached. Treatment continued for 3 to 6 months and a haemodynamic study was performed. After washout, the patients received the alternative treatment. In the upright position, during supine rest and during isometric as well as dynamic exercise, pinacidil lowered blood pressure more effectively than hydralazine. No differences between the 2 treatments were found in heart rate, stroke index, cardiac index, end systolic wall stress or glomerular filtration rate. Pulmonary mean and wedge pressure were lower during treatment with pinacidil. Forearm blood flow was higher and forearm vascular resistance lower during treatment with pinacidil. Cardiac contractility, judged from the systolic time interval ratio PEP: LVET, was lower during treatment with pinacidil compared with hydralazine. The median daily dose of pinacidil was 50mg and that of hydralazine 200mg. It was also noted that during long term treatment, pinacidil seemed more effective in reducing blood pressure than hydralazine.

Antihypertensive Agents↗
PubMed1988

Prenalterol in severe congestive heart failure. I. The immediate haemodynamic effects as compared to nitroglycerine.

The immediate haemodynamic effects of prenalterol and nitroglycerine were examined in 15 patients, with severe chronic heart failure. Prenalterol was given intravenously in increasing doses of 2, 4, and 8 mg. Cardiac index increased significantly by 16%, 24%, and 32%, respectively. Heart rate increased by 16%, 19%, and 24%. Stroke volume index, systemic artery pressure, pulmonary artery pressure, and right atrial pressure did not change. Prenalterol reduced systemic vascular resistance by 15%, 17%, and 24%, respectively. Forearm blood flow and forearm vascular resistance was unchanged. Cardiac index and heart rate were not changed by 0.5 mg nitroglycerine, administered sublingually. Systolic and diastolic blood pressure were on average reduced by 14% and 12%, respectively. Systolic and diastolic pulmonary artery pressure and right atrial pressure were similarly reduced by 17%, 31%, and 39%, respectively. Nitroglycerine lowered calculated systemic vascular resistance by 11%, whereas forearm blood flow and forearm vascular resistance was unchanged. The conclusion is that prenalterol acutely increased cardiac index and improved haemodynamics in 14 out of 15 patients, mainly due to an increased heart rate. Nitroglycerine did not change cardiac index in the same group of patients.

Aged↗
PubMed1988

Prenalterol in severe congestive heart failure. II. Long-term oral treatment. Results with comments on the methods for evaluation of drugs in congestive heart failure.

Nine patients with severe congestive heart failure were treated with a partial beta-1-agonist prenalterol for 9.6 months on average. Five of the nine patients improved with an increase in NYHA-functional capacity of one class. In four of these patients, the improvement was maintained for 12 months. Upon discontinuation, deterioration occurred only in one case; in the latter, improvement reoccurred on reinstitution of prenalterol treatment. Significant improvement on exercise testing, however, occurred only in two patients. Prediction as to which patients would benefit from oral prenalterol was not possible from the pretreatment haemodynamic variables; similarly, the effect of oral prenalterol treatment could not be predicted from the response to prenalterol given intravenously. A critical review of the methods for evaluation of therapeutic intervention in congestive heart failure concludes the article.

Administration, Oral↗
PubMed1987

Immediate haemodynamic effects of a novel partial agonist, beta 1-adrenoceptor blocking drug ICI 141,292 after intravenous administration to healthy young volunteers and patients with ischaemic heart disease.

ICI 141,292 is a new beta 1-adrenoceptor blocking drug. The beta 1-adrenoceptor antagonistic effect of ICI 141,292 was examined in a double-blind, randomised crossover study in eight healthy young volunteers and compared with atenolol. Three doses of ICI 141,292 (1, 2 and 4 mg) and atenolol 5 mg were administered intravenously. The attenuation in exercise induced tachycardia varied between 16.0 and 21.2% (P less than 0.01). A significant reduction in blood pressure could be demonstrated following all three doses of ICI 141,292 and atenolol during exercise. At rest in the sitting position HR decreased approximately 8% following all three doses of ICI 141,292 and 14.9% after atenolol 5 mg. No changes in blood pressure were observed under resting conditions after any of the drugs. In six patients with ischaemic heart disease the intrinsic sympathomimetic activity following intravenous administration of four sequential doses (0.5, 0.5, 1.0 and 2.0 mg) of ICI 141,292 was examined. HR decreased 7% (P less than 0.05) following ICI 141,292 1 mg with no further decrease following the succeeding doses. Cardiac output decreased 5.2% (P less than 0.05) following a cumulative dose of 4 mg. No significant changes were observed in mean arterial blood pressure, stroke volume or total peripheral resistance whereas an increase in supine resting mean pulmonary arterial pressure of 3.4 mm Hg (P less than 0.05) could be demonstrated. ICI 141,292 seems to be a potent (at least five times as potent as atenolol) beta 1-adrenoceptor blocking agent possessing moderate intrinsic sympathomimetic activity.

Adrenergic beta-Antagonists↗
PubMed1987

Progressive central hypovolaemia in man--resulting in a vasovagal syncope? Haemodynamic and endocrine variables during venous tourniquets of the thighs.

Hypotensive functional haemorrhage induced by venous pooling of blood in the legs has been reported to be characterized by a vasovagal reaction. In the present study these observations were extended by determination of the hormonal profile developed during progressive central hypovolaemia and an emotionally induced vasovagal syncope. In six subjects venous pooling resulted in normotensive central hypovolaemia, in one subject hypotensive central hypovolaemia was induced, and one subject experienced an emotionally induced vasovagal syncope. During normotensive central hypovolaemia heart rate increased from 58 +/- 4 to 76 +/- 4 beats min-1 (P less than 0.05) and cardiac output fell from 6.1 +/- 0.4 to 4.1 +/- 0.2 1 min-1. Pulse pressure and central venous pressure decreased from 64 +/- 4 to 53 +/- 4 mmHg, and from 8 +/- 2 to 3 +/- 2 mmHg, respectively. Adrenaline and noradrenaline increased from 87 +/- 10 to 120 +/- 20 pg/ml and from 196 +/- 33 to 370 +/- 50 pg/ml, respectively. Angiotensin II increased from 13 +/- 4 to 36 +/- 6 pg/ml and aldosterone from 63 +/- 9 to 180 +/- 27 pg/ml. In hypotensive central hypovolaemia the decrease in mean arterial pressure was accompanied by a decrease in heart rate and increments in the plasma concentrations of pancreatic polypeptide, indicating increased vagal activity and beta-endorphin, while plasma noradrenaline was unchanged. In emotionally induced syncope heart rate decreased to cardiac arrest for 13 s, associated with increments in the plasma concentrations of pancreatic polypeptide and beta-endorphin. It is concluded that normotensive functional haemorrhage in man is associated with increased sympathetic activity and that the qualitatively similar observations obtained during an emotionally and a hypovolaemic-induced hypotensive episode indicate that the hypotensive functional haemorrhage is characterized by a vasovagal reaction.

Adult↗
PubMed1987

Increased sympathetic tone in forearm subcutaneous tissue in primary hypothyroidism.

Sympathetic reflex regulation of subcutaneous blood flow (SBF) in the forearm was studied in eight patients with primary hypothyroidism. Diastolic arterial pressure was greater than or equal to 95 mmHg in five patients. SBF was determined by local clearance of Na99mTcO4. Sympathetic vasoconstriction normally seen after lowering the forearm 40 cm below heart level was absent since SBF only decreased by 4% (+/- 7%, P greater than 0.1) during these conditions. In head-up vertical position we noticed a diminished baroreceptor response as SBF at heart level was reduced by 11% (+/- 7%, P greater than 0.1) compared to supine position. After proximal local anaesthesia SBF increased by 351% (+/- 81%, P less than 0.01) and disclosed a normal vasoconstrictor response as SBF was reduced by 53% (+/- 5%, P less than 0.01) during arm lowering. Five of the treated patients were restudied in the euthyroid state. Mean arterial pressure was reduced in mean by 20 mmHg (+/- 6 mmHg, P less than 0.02) during treatment and a significant vasoconstriction was observed both during arm lowering (SBF = -52% (+/- 6%, P less than 0.02)) and in head-up vertical position (SBF = -45% (+/- 11%, P less than 0.02)). In conclusion sympathetic vasoconstrictor activity in adipose tissue is markedly increased in primary hypothyroidism. Sympathetic tone and arterial pressure are reduced during treatment.

Adult↗
PubMed1987

Haemodynamic effects of disopyramide using a new model of intravenous administration.

Intravenous treatment with disopyramide is usually performed by administration of a bolus injection of 150 mg given over 5 min. followed by a continuous infusion of 18-24 mg hour-1. A decrease in cardiac output is associated with this rapid bolus injection. Seven patients with ischaemic heart disease entered an open randomised cross-over trial to elucidate if an extension of the bolus injection time to 20 min. resulted in a smaller decrease in cardiac output. Cardiac index decreased significantly (P less than 0.001) in both situations, with maximum decrease observed at time 5 and 20 min., respectively (equivalent to the ending of the administration of 150 mg disopyramide). The decrease in Cardiac index (mean +/- S.E.M.) was identical in the two situations (2.56 +/- 0.23 to 1.78 +/- 0.21 l/min. X m2 (30%) and 2.66 +/- 0.17 to 1.94 +/- 0.19 l/min. X m2 (27%], respectively. Blood pressure was unchanged, while heart-rate (P less than 0.025) and preejection period index (P less than 0.005) increased significantly and to the same extent in the two situations. Significant correlations between the log free and log total serum concentration of disopyramide and the relative change in preejection period index of r = 0.840 (P less than 0.01) and 0.919 (P less than 0.01), respectively, were observed giving disopyramide over 5 min. A significant anticlockwise hysteresis was observed extending the time of administration to 20 min. As no haemodynamic advantages are achieved by the slower way of administration we would still recommend the bolus injection to be given over 5 min.

Disopyramide↗
PubMed1986

Haemodynamic effects of atenolol, pindolol and propranolol during adrenaline infusion in man.

In a double blind, cross over study the haemodynamic effects of an i.v. infusion of adrenaline during concomitant administration of atenolol, pindolol, propranolol or placebo were examined in 7 healthy volunteers. During coadministration with placebo, adrenaline caused an increase in systolic blood pressure (SBP) of 26 mm Hg and a decrease in diastolic blood pressure (DBP) of 20 mm Hg. Heart rate (HR) and stroke volume (SV) were increased by about 20-30%. Total peripheral resistance (TPR) fell significantly. When the subjects were pretreated with atenolol, the adrenaline increased SBP by 16 mm Hg, the DBP did not change, HR and SV increased by 19 and 30%, and TPR fell. During concomitant administration of the non-selective betablocker pindolol, which has strong intrinsic sympathomimetic activity (ISA), adrenaline increased SBP by 11 mm Hg and DBP by 17 mm Hg. This pure pressor response led to a significant reduction in HR and SV and an increase in TPR, probably mediated through the baroreceptors. The haemodynamic response to adrenaline during coadministration of propranolol was very similar to that seen after pindolol. It is concluded that a beta1-selective blocker interferes very little with the haemodynamic response to adrenaline, whereas it is changed to a pure pressor response during coadministration of a non-selective betablockers. ISA did not significantly modify the pressor response.

Adult↗
PubMed1986

Haemodynamic effects and kinetics of concomitant intravenous disopyramide and atenolol in patients with ischaemic heart disease.

The haemodynamic effects of concomitant intravenous administration of disopyramide (Norpace) and atenolol (Tenormin) were studied in a cross-over trial in 7 patients with ischaemic heart disease. Following 150 mg disopyramide i.v. the cardiac index (CI) and stroke volume index (SVI) decreased by 14% and 26%, respectively and the heart rate (HR) and preejection period index (PEPI) increased by 13% and 19%, respectively. A decrease in CI of 14% and HR of 21%, respectively were noted after intravenous administration of 7.5 mg atenolol; PEPI increased by 10% whereas SVI remained unchanged. The cardiac Index (CI) fell by 33% following the administration of both drugs. The effect on CI of the two drugs was additive. The effect of disopyramide and atenolol on HR, SVI and PEPI was not significantly modified by coadministration of the other drug. No change in blood pressure was observed after disopyramide or atenolol. A correlation (rho) of 0.540 and 0.387 was observed between the change in PEPI and the log free and total serum concentrations of disopyramide, respectively. Combined intravenous use of the two drugs in patients with incipient or overt heart failure is not recommended, unless it is due to the arrhythmia to be treated.

Aged↗
PubMed1986

Xamoterol, a new selective beta-1-adrenoceptor partial agonist, in the treatment of postural hypotension.

Three patients severely disabled from postural hypotension were treated with xamoterol, a selective beta-1-adrenoceptor antagonist with a high degree of partial agonist activity. Oral treatment (200 mg b.i.d.) was chosen on the basis of the effects of acute intravenous administration of xamoterol and pindolol, a non-selective beta-adrenoceptor antagonist with partial agonist activity. In these patients pindolol had a predominantly antagonist effect, whereas xamoterol had a predominantly agonist effect after intravenous administration. Oral treatment was carried out with placebo control in a single-blind fashion. The patients reported gradual improvement during the first days of treatment. After 1 month of oral treatment, heart rate had increased by 15 beats/min, systolic blood pressure from 131 to 170 mmHg, diastolic blood pressure from 77 to 91 mmHg and mean blood pressure by 22 mmHg (mean values, supine). During the placebo period (2 weeks) heart rate decreased to pretreatment levels and mean blood pressure was reduced by only 14 mmHg. The patients reported substantial improvement in their condition during active medication. Xamoterol seems to be a useful alternative in the treatment of postural hypotension.

Adrenergic beta-Agonists↗
PubMed1986

Metabolism of exercising skeletal muscle during beta 1-selective adrenoceptor blockade.

Concentrations of glycogen, glucose, glucose-6-phosphate and lactate in the lateral vastus muscle were measured in seven subjects before and after dynamic muscle exercise at a work load of 75% of each subject's maximal working capacity, and with and without intravenous administration of the beta 1-selective beta-adrenoceptor blocking agent, atenolol. Pulmonary oxygen uptake was measured during exercise. Heart rate and arterial blood pressure were measured throughout the study. Arterial concentrations of glucose, lactate and free fatty acids were measured at rest and during exercise. The muscle concentration of glycogen and the extent of glycogen depletion with exercise were not influenced by the beta 1-adrenoceptor blocker. Similarly, there was no change in the muscle concentrations of glucose, glucose-6-phosphate and lactate. Heart rate decreased at rest and during exercise. Arterial blood pressure was not influenced by beta-blockade. Pulmonary oxygen uptake decreased by 6.5%. The exercise induced rise in arterial blood concentration of free fatty acids was abolished by beta 1-selective beta-blockade. It is concluded that the decrease in lactate release from exercising muscles during beta 1-adrenoceptor blockade seen in other studies cannot be explained by an impaired breakdown of muscle glycogen. It may be inferred, however, that a reduced availability of free fatty acids in the exercising muscles during beta 1-selective (and non-selective) beta-blockade may enhance the combustion of pyruvic acid and thereby decrease the production of lactate.

Adult↗
PubMed1986

Reliability of a 99mTc-DTPA gamma camera technique for determination of single kidney glomerular filtration rate. A comparison to plasma clearance of 51Cr-EDTA in one-kidney patients, using the renal clearance of inulin as a reference.

In a recent paper we described a method for calculation of single kidney glomerular filtration rate (SKGFR) from the 99mTc-DTPA renogram obtained by gamma camera. Determination of the injected dose and collection of urine or blood was not needed. In this paper the reliability of the method was compared to other methods for estimation of GFR in 20 unilaterally nephrectomized patients. The renal clearance of inulin served as reference measure of GFR. The values for SKGFR obtained from the renograms and from the estimated endogenous creatinine clearances according to serum creatinine concentration and a nomogram were both accurate. The reliability of the renography method was significantly better judged by less variance in the estimates. SKGFR calculated from the plasma clearance of 51Cr-EDTA overestimated the renal clearance of inulin on an average by 11.3%. No difference was found in the variance of the values obtained from the renograms and from the plasma clearances of 51Cr-EDTA compared to the renal clearance of inulin. Apart from the inaccuracy in the GFR values calculated from the plasma clearance of 51Cr-EDTA, the reliability of these two methods was equal. The day to day variation of SKGFR estimated from the renograms in 24 patients (48 kidneys) with SKGFR values from 5 to 76 ml/min was 8.8%. This equals the day to day variation in the plasma clearance of 51Cr-EDTA.

Aged↗