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Biomedical subjects

J Trap-Jensen

Publications and source records attributed to J Trap-Jensen.

At least 91 records · Page 5Linked to original sources
PubMed1979

Cardiovascular and adrenergic effects of cigarette smoking during immediate non-selective and selective beta adrenoceptor blockade in humans.

The cardiovascular and adrenergic responses to cigarette smoking during acute selective and non-selective beta adrenoceptor blockade were studied in seven young healthy volunteers in a double blind cross-over fashion. Heart rate, arterial blood pressure, forearm blood flow and plasma levels of adrenaline and noradrenaline were determined before and during the terminal 5 min period of 15 min smoking test. During smoking, plasma concentrations of adrenaline increased markedly and evenly by approximately 0.3 ng/ml in all three experimental sessions. Plasma concentrations of noradrenaline remained unchanged. Propranolol, a non-selective beta blocker, caused a marked rise in diastolic and mean blood pressure and forearm vascular resistance during smoking. This response was not seen in the control series or after selective beta-1 blockage with atenolol. This difference is attributable to propranolol's blockade of adrenaline's vasodilating effect mediated by beta-2 receptors in the resistance vessels. Furthermore, atenolol attenuated the systolic blood pressure and tachycardiac responses induced by cigarette smoking by comparison with placebo. This study suggests that selective beta-1 blockers are preferable in the management of patients who are habitual smokers.

Adult↗
PubMed1978

Effect of labetalol on plasma noradrenaline and adrenaline in hypertensive man.

Injection i.v. of labetalol, a new adrenergic alpha- and beta-blocking agent, decreased arterial blood pressure in 9 hypertensive subjects resting in the supine position, when standing and during supine exercise. Heart rate after labetalol was unchanged in the resting supine position, and it fell in the latter two conditions. Plasma noradrenaline concentration was higher after labetalol in all three experiments as compared to a control study. Plasma adrenaline after labetalol was increased only in the standing position, when the highest plasma noradrenaline concentrations were observed. Blood glucose concentration tended to increase after labetalol, but the difference was not statistically significant. The changes in plasma noradrenaline and blood glucose after labetalol mimic findings observed after alpha-adrenergic receptor blockade. The beta-adrenergic receptor blocking property of labetalol is responsible for the reduced heart rate and it is likely to contribute to the higher plasma noradrenaline concentration observed when standing and during supine exercise.

Adult↗
PubMed1978

Effect of adrenergic beta receptor blockade on ethanol elimination and on ethanol-induced changes in carbohydrate and lipid metabolism in man.

The effect of adrenergic beta receptor blockade on the elimination rate of ethanol was studied in seven healthy young men. The studies were performed before and after 14 days of propranolol 240 mg/day: the ethanol was given per-orally--0.8 mg/kg b.w. The blood concentration of ethanol, glucose, lactate and glycerol, and the plasma concentration of free fatty acids and triglycerides were followed in samples from the superior vena cava taken every 20 min for four hours. The splanchnic hepatic blood flow was estimated with a single i.v. injection of indocyanine green. The absorption rate, absorption fraction and elimination rate of ethanol were not changed by propranolol. The splanchnic hepatic blood flow was significantly reduced (mean 19 per cent) during beta receptor blockade. The ethanol-induced change in the concentration of glucose, lactate and free fatty acids was affected by propranolol, the time-concentration curves for glucose and lactate being significantly elevated and that for free fatty acids being significantly reduced. The time-concentration curves for glycerol and triglycerides did not differ in the two studies.

Adolescent↗
PubMed1978

The distensibility of the resistance vessels of skeletal muscle in hypertensive patients.

The distensibility of the resistance vessels of skeletal muscle was evaluated in 23 patients with essential arterial hypertension (WSHO grade I--II), and in 14 normotensive control sugjects. Five of the hypertensive patients were well treated for over 2 years and 18 were untreated. The 133Xenon wash-out rate from the anterior tibial muscle during reactive hyperemia was recorded before and during an increase of the vascular transmural pressure, brought about by application of a subatmospheric pressure to the leg. At ambient pressure the 133Xenon wash-out rate did not differ between the normotensive and hypertensive subjects, reflecting equal muscle blood flows. However, when the transmural pressure was augmented the 133Xenon wash-out rate in the normotensive subjects increased about twice as much as in the hypertensive patients. This suggests a decreased distensibility of the resistance vessels in hypertensive patients as compared to normotensive subjects, and supports the concept that structural changes of these vessels take place in arterial hypertension. Since the vascular distensibility was equally reduced in the untreated and well treated hypertensive patients it is indicated that the structural changes in the resistance vessels of the leg muscles do not readily decline during antihypertensive treatment.

Adult↗
PubMed1978

Hepato-biliary scintigraphy and hepatography with Tc-99m diethyl-acetanilido-iminodiacetate in obstructive jaundice.

Tc-99m diethyl-IDA was used for combined serial hepato-biliary scintigraphy and processing of hepatographic curves, using a scintillation camera and an image-processing system. Patients with obstruction of the common bile duct, proven by operation, were investigated. Hepatograms from an area of interest corresponding to the periphery of the right liver lobe varied predictably with changes in the serum levels of alkaline phosphatase and bilirubin. Both anatomical and functional information was obtained. The investigation could be carried out even under reduced liver function. Hepatic uptake of the agent was noted at serum alkaline phosphatase levels up to 1000 U/l and serum bilirubin levels up to 170 mumol/l.

Acetanilides↗
PubMed1977

Regulation of gluconeogenesis and ketogenesis during rest and exercise in diabetic subjects and normal men.

The splanchnic-hepatic metabolism of glucose, lactate, pyruvate, alanine, glycerol, non-esterified fatty acids (NEFA), ketone bodies and oxygen were investigated in five normal men and six juvenile diabetic subjects at rest and during exercise after an overnight fast. A linear relationship was found between load (arterial concentration multiplied by hepatic blood flow) and splanchnic-hepatic uptake of lactate, pyruvate, glycerol and NEFA. The uptake of alanine was highly sensitive to load, but was also regulated by the concentration of hepatic venous glucagon. The uptake of pyruvate was high in exercising diabetic subjects, who had a high lactate/pyruvate concentration ratio in hepatic venous blood. The rate of uptake of the total measured gluconeogenic precursors was significantly higher in the diabetic group at a given load. The rate of ketogenesis was linearly related to the NEFA load in both groups; however, the rate of ketogenesis was twofold at a given load in the diabetic group. The highest rates of ketogenesis were found coincident with the highest concentrations of glucagon in hepatic venous blood. The observed antiketogenic effect of exercise was due to a decreased load of NEFA, mainly caused by a decrease in the hepatic blood flow.

Adult↗
PubMed1977

Central and regional circulatory effects of adding arm exercise to leg exercise.

7 young, healthy, male subjects performed exercise on bicycle ergometers in two 20 min periods with an interval of 1 h. The first 10 min of each 20 min period consisted of arm exercise (38--62% of Vo2 max for arm exercise) or leg exercise (58--78% of Vo2 max for leg exercise). During the last 10 min the subjects performed combined arm and leg exercise (71--83% of Vo2 max for this type of exercise). The following variables were measured during each type of exercise: oxygen uptake, heart rate, mean arterial blood pressure, cardiac output, leg blood flow (only during leg exercise and combined exercise), arterio-venous concentration differences for O2 and lactate at the levels of the axillary and the external iliac vessels. Superimposing a sufficiently strenuous arm exercise (oxygen uptake for arm exercise greater than 40% of oxygen uptake for combined exercise) on leg exercise caused a reduction in blood flow and oxygen uptake in the exercising legs with unchanged mean arterial blood pressure. Superimposing leg exercise on arm exercise caused a decrease in mean arterial blood pressure and an increased axillary arterio-venous oxygen difference. These findings indicate that the oxygen supply to one large group of exercising muscles may be limited by vasoconstriction or by a fall in arterial pressure, when another large group of muscles is exercising simultaneously.

Adult↗
PubMed1977

99mTc-DTPA scintillation-camera renography: a new method for estimation of single-kidney function.

A new method of combined serial scintigraphy and renography, using a scintillation camera and 99mTc-DTPA is evaluated. Renographic curves, corresponding to light-pen "areas of interest" over the renal parenchyma, were processed. "Blood-background" curves were recorded from an external detector over the temporal region of the head and also from an "area of interest" corresponding to the aorta and inferior vena cava. The uptake phase of the renogram was always linear. The sum of the slopes of the uptake phase of both kidneys correlated well with the measured glomerular filtration rate in 25 patients with renal insufficiency of various degrees. Single-kidney function estimated from the slopes correlated reasonably well with single-kidney function estimated from 131I-Hippuran renography with external detectors. The method described minimizes errors in the estimation of single-kidney function, and both anatomic and functional information is obtained.

Humans↗
PubMed1976

Leg muscle blood flow during reactive hyperemia. Effects of different body positions, and of subatmospheric pressure.

In normal man at rest transition from the supine to the upright body position is accompanied by autoregualtion of the blood flow to tissues in the dependent extremities. In 11 young healthy males the influence of postural changes and external pressure changes on the blood flow in the anterior tibial muscle during reactive hyperemia was studied. The muscle blood flow was evaluated by means of the Xenon-133 wash-out technique. Transmural pressure changes in the resistance vessels were estimated by measuring the systolic blood pressure at ankle level, using the strain-gauge plethysmograph technique. The mean leg muscle blood flow increased from 48 ml - 100 g-1 - min-1 in a body position with the legs elevated 65 cm above heart level, to 101 ml - 100 g-1 - min-1 in the supine position, and to 151 ml - 100 g-1 - min-1 in a sitting position with dependent legs 70 cm below heart level. The muscle blood flows increased from 92 ml - 100 g-1 - min-1 at ambient pressure to 139 ml - 100 g-1 - min-1 at a subatmospheric pressure of -50 mm Hg. The differences were highly significant (P less than 0.001). Systemic blood pressure measured at heart level did not change during postural changes and external pressure changes. The post-ischemic muscle blood flow was found to increase with the increasing vascular transmural pressure. It is concluded that during reactive hyperemia the normal compensatory vaso-reactions can be inactivated, so that the vessels react passively to changes in the transmural pressure.

Adult↗
PubMed1976

The effect of metabolic regulation on microvascular permeability to small and large molecules in short-term juvenile diabetics.

The microvascular permeability to small and large molecules was studied during good and poor metabolic regulation in ten short duration juvenile diabetics. The following variables were measured; daily urinary albumin and beta2-microglobulin-excretion rates, whole body transcapillary escape rate of albumin (TER), glomerular filtration rate (GFR), capillary filtration coefficient (CFC), and capillary diffusion capacity (CDC). The urinary albumin and beta2-microglobulin concentration were measured by sensitive radioimmunoassays; TER was detemined from the initial disappearance of intravenously injected 125I-labelled human serum albumin; GFR was measured on the forearm by straingauge plethysmography and CDS for 51Cr-EDTA clearance; CFC was measured on the forearm by straingauge plethysmography and CDC, for 51Cr-EDTA was determined in the jyperaemic anterio tibial muscle by the local clearance technique. All the above mentioned variables, except CDC, were significantly increased during poor metabolic regulation, indicating a functional microangiopathy. The mechanisms of these alterations appear to be increased filtration pressure in the microcirculation and/or increased porosity of the microvasculature. The findings of increased microvascular albumin passage are compatible with the hypothesis that the organic - histologicallly demonstrated - diabetic microangiopathy is a long-term effect of periods of increased extravasation of plasma proteins, with subsequent protein deposition in the microvascular wall, i.e. the concept to plasmatic vasculosis.

Adolescent↗
PubMed1976

Heart rate and arterial blood pressure during exercise in patients with angina pectoris. Effects of training and of nitroglycerin.

In 29 patients with typical exertional angina pectoris, intra-arterial systolic blood pressure (SBP), heart rate (HR), and the rate-pressure product (RPP = HR X SBP X 10(-2) were continuously recorded during repeated bouts of leg or arm exercise. Development of chest pain was independent of the workload and occurred at a fairly constant value of RPP, of HR, and of SBP in each patient for a given type of exercise, but the pain threshold values for all three variables were consistently higher during arm exercise than during leg exercise. The reproducibility of the pain threshold values was assessed for leg exercise. The variation, based on individual coefficients of variation, ranged from 1.3% to 13% (group mean, about 6%). There was no significant difference between the SBP values obtained by the traditional, noninvasive cuff technique and the values during intra-arterial monitoring. In 25 patients a physical training program of an average of three months increased the maximal amount of work (watt X sec) performed before onset of pain by 100%. The most conspicuous effect of training on cardiac function was a 10% reduction of HR at a given workload, SBP being unchanged. Over-all, the data suggest that the increased exercise capacity caused by training could be accounted for by the reduction in the relation between RPP and external workload. The improvement in exercise capacity resulting from training was on the same level of magnitude as the 90% increase obtained in 11 untrained patients after administration of 0.25 to 0.50 mg of nitroglycerine sublingually prior to exercise. In contrast to the finding after training, nitroglycerin administered to subjects increased HR by 10%, but reduced SBP by 13%, RPP remaining unchanged. Therefore to explain the effect of nitroglycerin on exercise capacity additional economizing changes in myocardial performance (e.g., reduction of heart volume) are required.

Adult↗
PubMed1975

Pulmonary ventilation, blood gases, and blood pH after training of the arms or the legs.

In two groups of young healthy subjects who performed arm training (N = 5) and leg training (N = 5), respectively, the respiratory adaptation to submaximal exercise with trained and nontrained muscle groups was compared by measurement of the ventilatory equivalent (Ve/Vo2, pH, and blood gases (Pco2, Po2, and So2) in arterial blood and in venous blood from exercising extremities. After training Ve/Vo2 was significantly reduced during exercise with trained muscles, but unchanged during exercise with nontrained muscles. The reduction in Ve/Vo2 was closely related to a less pronounced increase in heart rate and in arterial lactate content, but showed no quantitative correlation to changes in arterial adaptations in trained muscles are mainly responsible for the reduction in Ve/Vo2. After training during exercise with trained as well as nontrained muscles a shift to the right of the blood oxygen dissociation curve occurred as extremities was lower while corresponding Po2 was higher.

Adult↗