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Biomedical subjects

A Westheim

Publications and source records attributed to A Westheim.

At least 19 recordsLinked to original sources
PubMed1992

Haemodynamic and neurohumoral effects of cold pressor test in severe heart failure.

The effect of a cold pressor test (CPT) on haemodynamics in relation to general and regional sympathetic activity and arginin vasopressin (AVP), was studied in eleven patients with severe congestive heart failure (CHF). Compared to an age-matched control group (C), resting arterial plasma noradrenaline (NA) (419 +/- 77 vs. 182 +/- 15 pg ml-1), and adrenaline (A) (142 +/- 28 vs 54 +/- 10 pg ml-1) were higher (P less than 0.05) in CHF. AVP showed no significant difference (14 +/- 4 vs. 9 +/- 4 pg ml-1). During CPT systolic and diastolic blood pressure and systemic vascular resistance increased (P less than 0.01), as did NA (delta 114 +/- 39 pg ml-1, P less than 0.01), A (delta 33 +/- 10 pg ml-1, P less than 0.01) and heart rate (delta 10 beats min-1, P less than 0.01). The myocardial v-a difference of NA decreased (P less than 0.05), but was unchanged across the renal vascular bed during CPT. The a-v difference of NA in the hepatic vascular bed, and fractional extraction of A in the coronary sinus, renal and hepatic vascular beds remained unchanged during CPT. AVP did not change significantly and no change in cardiac index or left ventricular filling pressure was observed during CPT. These data suggest that despite an increased activation of the sympathetic nervous system at rest, a further increase in blood pressure and catecholamines took place during CPT. Thus, the effect of a CPT which activates the central sympathetic system seems not to be altered in patients with severe CHF.

Aged↗
PubMed1992

Physical activity and the metabolic cardiovascular syndrome.

Hyperinsulinemia, lipid abnormalities, and impaired fibrinolytic capacity may accompany hypertension, and comprise the metabolic cardiovascular syndrome. They are all independent risk factors for coronary artery disease. Lifestyle modifications can reduce the coronary artery risk. Physical activity has been shown to improve insulin sensitivity, reduce hypertriglyceridemia, improve fibrinolytic capacity, and reduce the blood pressure. A sedentary lifestyle is associated with increased mortality compared to a physically active lifestyle. Hypertensive patients, who often have other atherothrombogenic risk factors, should be encouraged to undertake physical activity as an adjuvant to other nonpharmacological interventions as well as to pharmacological treatment.

Blood Pressure↗
PubMed1991

[Ambulatory non-invasive 24-hour blood pressure measurement--do we need it?].

The introduction of non-invasive, portable, automatic blood pressure measurement devices enables characterization of the blood pressure profile throughout the day in an ambulatory setting. The article advises against uncritical use. 24-hour ambulatory blood pressure measurements have become a valuable tool in scientific research, however, especially in studies dealing with antihypertensive efficacy. In hypertensive patients with "white coat hypertension", important data cannot be obtained without the use of 24-hour ambulatory blood pressure monitoring or blood pressure measurement at home.

Ambulatory Care↗
PubMed1991

[The effect of doxazosin on blood pressure, lipids, fibrinogen and plasminogen activator inhibitor. A comparative study among smokers and non-smokers with essential hypertension].

Hypertensive cigarette smokers run particularly high risk of coronary heart disease. Doxazosin, which has beneficial effects on haemodynamic factors and lipid metabolism, may be a suitable agent for treating these patients. The effects on blood pressure and metabolic parameters were investigated in a 16-week, open, parallel, comparative study comprising 64 heavy cigarette smokers and 69 non-smokers who received doxazosin after four weeks on placebo. Eight patients (three smokers and five non-smokers) dropped out due to adverse effects. Blood pressure was significantly reduced in both groups, but there was no change in heart rate. Doxazosin induced a decrease in the triglyceride, total cholesterol and LDL-cholesterol levels, and an increase in HDL-cholesterol concentration. Thus, doxazosin has favourable effects on atherogenic factors in smoking hypertensive patients. There was also a significant lowering of plasma fibrinogen levels and plasminogen activator inhibitor (PAI-1) concentration in non-smokers.

Adult↗
PubMed1991

Awareness of high blood pressure increases arterial plasma catecholamines, platelet noradrenaline and adrenergic responses to mental stress.

Thirty-six, 19-year-old men within the 95th percentile of mean blood pressure (110 mmHg) at a routine medical screening were randomized into two groups and requested to return for a follow-up visit in 2 weeks. One group was sent a neutral letter, while the other was sent a letter conveying the information that their blood pressures were elevated. After 15 min sitting in the laboratory, there was a significantly higher heart rate (P less than 0.05) in the informed group. Thirteen informed and 13 uninformed subjects were examined further by intra-arterial blood pressure recording and serial sampling of arterial catecholamines during cold pressor and mental stress tests. The study was undertaken examiner-blind. Informing the subjects of high blood pressure increased both baseline plasma noradrenaline (P less than 0.01) and adrenaline (P less than 0.05) and intraplatelet noradrenaline (P less than 0.05). Blood pressure (P less than 0.05) and heart rate (P less than 0.05) increased significantly more in the informed group when the subjects were told of the cold pressor test. In addition, there were exaggerated adrenaline (P less than 0.05) and diastolic blood pressure (P less than 0.05) responses to mental stress in the informed group. Thus, awareness of high blood pressure in young men may increase sympathetic tone and responses as measured in the laboratory. Conclusions from studies on early pathogenesis of essential hypertension should therefore be drawn with more caution when patients are aware of their high blood pressure.

Adult↗
PubMed1991

Faster and more reliable absorption of adrenaline by aerosol inhalation than by subcutaneous injection.

1. The aim of the present study was to compare absorption of adrenaline given by aerosol spray inhalation with absorption after subcutaneous injection. 2. Arterial plasma adrenaline was measured in nine healthy volunteers following adrenaline administration by both methods. 3. Following inhalation of 20 puffs of adrenaline aerosol, 0.15 mg/puff, a peak arterial adrenaline concentration after 1 min and a rapid fall to baseline from this peak occurred. 4. When given by subcutaneous injection absorption was slower with a peak arterial adrenaline concentration after 4 min. The fall in arterial adrenaline from this peak level was not statistically significant within 30 min after injection. 5. There was less intersubject variation of arterial adrenaline concentration following inhalation when compared with injection. 6. Heart rate, blood pressure and finger tremor followed the changes in arterial adrenaline concentrations. 7. These results indicate that absorption is more reliable when adrenaline is given by inhalation. The rapid fall in arterial adrenaline following inhalation, suggests that repeated inhalations are necessary when such adrenaline therapy is required.

Absorption↗
PubMed1990

Doxazosin in combination with atenolol in essential hypertension: a double-blind placebo-controlled multicentre trial.

Doxazosin (mean dose 11 mg) given once daily in combination with 100 mg atenolol (n = 44) was compared with placebo and atenolol (n = 43) in a double-blind, multicenter study in patients with mild to moderate essential hypertension. In the atenolol/doxazosin-treated group, standing blood pressure significantly decreased by 17.0/12.3 mm Hg compared to 6.2/6.7 mm Hg in the atenolol/placebo group whereas supine blood pressure decreased by 13.2/9.8 mm Hg and 9.2/6.0 mm Hg, respectively in the two groups. Serum lipids did not change significantly in either group. The majority of side-effects reported were mild and transient. This study confirms that doxazosin may be safely combined with a beta-blocker. Doxazosin proved to be well tolerated and effective in patients with blood pressure refractory to atenolol alone.

Adolescent↗
PubMed1990

Renal haemodynamic and sympathetic responses to head-up tilt in essential hypertension.

Nine mild-to-moderate hypertensive patients (HT), aged 41 +/- 0.6 years (mean +/- SEM) and nine age-matched normotensive control subjects (NT) were tilted to 60 degrees for 10 min. During tilt, both systolic (S) blood pressure (BP) (p less than 0.01) and diastolic (D) BP (p less than 0.05) increased in HT, but not in NT. At supine rest renal blood flow was higher in HT than in NT and increased by 17% in HT during tilt, while a decrease of 13% was observed in NT (p less than 0.05). Renal vascular resistance was unchanged in HT during tilt, while a significant increase (p less than 0.01) was observed in NT. Arterial plasma noradrenaline increased in both groups (p less than 0.05) during tilt, significantly more in HT than in NT (p less than 0.05). No statistically significant difference was observed between the groups in renal catecholamine uptake or release. Our data indicate enhanced general sympathetic and circulatory responses to tilt in subjects with mild-to-moderate essential hypertension. However, the enhanced haemodynamic and sympathetic responses were not shared by hypertensive kidneys and renovascular resistance remained unaffected by tilt.

Adult↗
PubMed1990

Selective alpha 1 inhibition with doxazosin in hypertensive smokers and non-smokers: haemodynamic and metabolic effects.

Hypertensive cigarette smokers have an especially high risk of coronary heart disease. Doxazosin, which has beneficial effects on haemodynamic factors and lipid metabolism, may be suitable for treating these patients. The haemodynamic and metabolic effects of doxazosin were investigated in a 16-week open, parallel, comparative study of 64 heavy cigarette smokers and 69 non-smokers after a 4-week placebo period. Of the 133 patients who entered, six patients (one smoker and five non-smokers) withdrew due to adverse events. Doxazosin significantly reduced blood pressure without reflex tachycardia in both the smokers and the non-smokers. The therapeutic success rates (reduction in sitting diastolic blood pressure to less than or equal to 90 mmHg and greater than or equal to 5 mmHg reduction, or greater than or equal to 10 mmHg reduction from baseline) were similar for the smokers (93.3%) and the non-smokers (92.5%). Doxazosin significantly decreased total cholesterol and low-density lipoprotein (LDL) cholesterol, but increased high-density lipoprotein (HDL) cholesterol and the HDL:total cholesterol ratio in both smokers and non-smokers. Doxazosin corrected the reduction in HDL cholesterol caused by smoking; compared with baseline, doxazosin increased HDL cholesterol by 19% in hypertensive smokers. The beneficial effects of doxazosin on blood pressure and the lipid profile were apparent in the change in the 10-year probability of developing coronary heart disease as calculated by the Framingham equation; the calculated risk of coronary heart disease decreased by 39% in smokers and by 33% in non-smokers. Plasma fibrinogen and plasminogen activator inhibitor, which independently contribute to atherosclerosis, were significantly reduced by doxazosin in the non-smokers but not in the smokers.

Adrenergic alpha-Antagonists↗
PubMed1989

Late sequelae of lung contusion.

Twenty-four patients with severe lung contusion and multiple rib fractures were studied at a mean 4.9 years (range 2-9 years) after injury. All patients had been in good health before the accident. After the accident 15 (63 per cent) patients had respiratory symptoms such as dyspnoea at rest or moderate exercise (4), pain (8), cough or increased expectoration (11) and frequent bronchopulmonary infections (5). Three patients had changed their job because of respiratory disturbance. The average vital capacity, forced expiratory volume in 1 s, maximal voluntary ventilation and CO transfer factor were reduced respectively to 87, 88, 82 and 83 per cent of predicted values (P less than 0.01), while total lung capacity, residual volume and helium mixing time showed no definite changes (P greater than 0.05). Arterial blood gases at rest and at maximum exercise showed slight changes only. Maximal working capacity and ECG, as well as the ventilatory cost of moderate exercise were normal, where as the CO2 recovery time after moderate exercise was slightly increased (P less than 0.05). Overall there was a tendency towards poorer function in patients treated with artificial ventilation. Chest radiographs were normal in 10 patients (42 per cent), and moderate changes were seen in 14 patients. Diaphragmatic movements were essentially normal in all patients. Severe injury to the chest causes frequent respiratory symptoms. However, objective tests were only moderately reduced when compared with normal values. There was no unequivocal association between the subjective symptoms and the pulmonary function.

Adult↗
PubMed1989

Effect of dopamine and dopamine-antagonist infusion on blood platelet count, size and release reaction in hypertensive and normotensive subjects.

To examine the effect of dopamine on in vivo platelet function and a possible platelet contribution to the clearance of dopamine we measured platelet count, platelet size and plasma concentration of the platelet specific protein beta-thromboglobulin (BTG) in groups of 40 year old untreated hypertensive and normotensive men. One hypertensive (n = 10) and one normotensive (n = 10) group received dopamine infusion at doses from 0.5 to 2.0 micrograms/kg/min which increased plasma dopamine 100-fold from baseline. Two other groups of hypertensive (n = 10) and normotensive (n = 11) subjects received 10 mg of the dopamine antagonist metoclopramide intravenously, upon which serum prolactin concentration increased 10-fold. No significant effect on platelet function in any group was observed during these interventions. Platelet phenol-sulphotransferase may contribute to dopamine conjugation. However, the selected platelet parameters correlated only weakly with dopamine kinetics during the infusion. Neither dopamine nor a dopamine antagonist altered the selected platelet parameters, nor did these parameters influence the clearance of dopamine during a short-lasting pharmacological infusion.

Blood Platelets↗
PubMed1988

Decreased serum phosphate in essential hypertension. Related to increased sympathetic tone.

Forty-year old men with untreated mild essential hypertension (n = 35) had decreased serum phosphate (P less than 0.001) concomitant with elevated resting plasma epinephrine (P less than 0.05) and heart rate (P less than 0.001) compared with age-matched, normotensive control men (n = 44). Blood pressure correlated negatively with serum phosphate (P less than 0.001) and positively with plasma epinephrine (P less than 0.01) and heart rate (P less than 0.01). Serum phosphate was significantly lowered during infusion of epinephrine, increasing arterial plasma epinephrine within the lower pathophysiological range corresponding to arousal reactions. Serum concentrations of immunoreactive parathyroid hormone were unchanged. Thus, hypophosphatemia in patients with mild essential hypertension appears to be inversely related to sympathetic adrenal tone and may be caused by increased plasma epinephrine within pathophysiologic arterial concentrations.

Adult↗
PubMed1988

Increased platelet and vascular smooth muscle reactivity to low-dose adrenaline infusion in mild essential hypertension.

During low-dose adrenaline infusion, platelet count, platelet size, plasma beta-thromboglobulin (BTG) and forearm vascular resistance (FVR) were measured in twelve 40-year-old men with mild, untreated hypertension. The average platelet count increased from 195 to 226 X 10(9)/l (P less than 0.001), platelet size from 7.31 to 7.53 X 10(-15)/l (P less than 0.01), BTG from 0.61 to 1.08 nmol/l (P less than 0.02) and FVR decreased from 97 to 58 (arbitrary units; P less than 0.001) during the infusion. The change in platelet count reflects splenic release of platelets, the change in plasma BTG reflects platelet release reaction, while the reduced FVR reflects vascular smooth muscle cell relaxation. In 11 normotensive men aged 40 years, platelet count increased from 187 to 201 X 10 g/l (P less than 0.01) during an equal low-dose adrenaline infusion. This increase in platelet count is significantly less than in the hypertensive group (P less than 0.01). There was statistically no significant change in platelet size, BTG or FVR in the normotensive group. Arterial adrenaline rose from 0.5 to 2.5 nmol/l in the hypertensive and from 0.5 to 2.4 nmol/l in the normotensive group. A third group of 12 normotensive men received saline infusion: neither platelet parameters nor FVR changed in this group. Thus, a small and equal dose of adrenaline elicited a greater increase in platelet count, an enhanced platelet release reaction and a more pronounced forearm vasodilation in hypertensive than in normotensive subjects.

Adult↗
PubMed1988

Hyper-responsiveness to low-dose epinephrine infusion in mild essential hypertension.

The present study was undertaken to evaluate the effects of intravenous infusion of small amounts of epinephrine on haemodynamics, renal electrolyte excretion and blood platelets in essential hypertension. Arterial plasma epinephrine concentrations were increased during the infusion to approximately 2.5 nmol/l both in a group of 40-year-old men with untreated mild essential hypertension (blood pressure 154 +/- 3/100 +/- 3 mmHg, n = 12) and in a group of age-matched male controls (124 +/- 3/78 +/- 2 mmHg, n = 11). In the hypertensive group only, mean blood pressure decreased, forearm blood flow increased, forearm vascular resistance decreased (P less than 0.001 for all) and the urinary excretion of sodium and potassium increased (P less than 0.01 for both). The hypertensive group also responded with an increase in plasma beta-thromboglobulin (P less than 0.05), blood platelet size (P less than 0.05) and a higher increase in platelet counts than in the normotensive group (P less than 0.05). Thus, in several ways the hypertensive patients showed a hyper-responsiveness to amounts of epinephrine which corresponds well to the plasma concentration achieved during psychological and physical activity.

Adult↗
PubMed1988

Changes in coronary haemodynamics and myocardial metabolism at rest and during exercise after a cardiotonic drug (prenalterol) in patients with coronary artery disease.

To elucidate the myocardial metabolic and haemodynamic effects of an inotropic drug in patients with coronary artery disease (CAD) without evident congestive heart failure (CHF), the acute effects of prenalterol were studied in nine patients. Patients with documented CAD by leftsided cardioangiography and end-diastolic pressure greater than 15 mm Hg were included in the study. They were examined at rest and during supine exercise at a level just below their anginal threshold before and after prenalterol. At rest, rate pressure product (RPP) increased by 40% (P less than 0.01), cardiac index rose 20% (P less than 0.01), cardiac venous flow (CVF) increased by 18% (P less than 0.05), and myocardial oxygen consumption (MVO2) increased by 20% (P less than 0.05) after prenalterol administration. Despite a decrease in mean pulmonary capillary venous pressure (PCV) of 40% (P less than 0.01), myocardial lactate extraction fell significantly (P less than 0.01) and lactate production was observed in three of nine patients compared to before prenalterol administration. During exercise, RPP increased by 20% (P less than 0.01), cardiac index remained unchanged, CVF increased by 25% (NS) and MVO2 showed a tendency to an increase (NS) after prenalterol administration. Mean PCV pressure decreased by 30% (P less than 0.01). Myocardial lactate extraction was markedly reduced during exercise (P less than 0.01) and five of nine patients showed lactate production compared to that before prenalterol administration. Thus, despite a decrease in left ventricular filling pressure, increased myocardial oxygen demand occurred after acute administration of prenalterol. Prenalterol and probably similar inotropic drugs should be used cautiously in patients with CAD without clinical evidence of congestive heart failure.

Catheterization, Swan-Ganz↗
PubMed1988

Sodium depletion increases platelet and plasma catecholamines in hypertensive men.

The catecholamine content in blood platelets is considerably higher than that in plasma, and platelet catecholamines must be taken up from plasma, since blood platelets lack enzymes for catecholamine synthesis. However, it is unknown whether platelets take up and store catecholamines during physiological in vivo increments in plasma catecholamines. Previously untreated 50-year-old men (n = 17) with mild to moderate essential hypertension were given a low sodium diet for 2 weeks. Urinary excretion of sodium decreased from 201 +/- 11 (SE) to 24 +/- 5 and 19 +/- 4 mmol/24 hr after 1 and 2 weeks, respectively. During the first week, the blood platelet concentration of norepinephrine increased from 27.2 +/- 2.9 to 39.6 +/- 4.7 pg/mg (p less than 0.005) and venous plasma norepinephrine increased from 3.7 +/- 0.4 to 5.6 +/- 0.5 pg/ml (p less than 0.005), and venous plasma dopamine increased from 26 +/- 4 to 41 +/- 5 pg/ml (p less than 0.05). During the second week, both plasma and platelet norepinephrine and dopamine remained elevated. Platelet epinephrine showed a small increase from baseline to the second week (p less than 0.05), but no concomitant increase in plasma epinephrine occurred. Thus, sodium depletion increases both platelet and plasma catecholamines and blood platelets may take up catecholamines in vivo. Platelet catecholamine content may be an integrated measure of plasma catecholamine concentrations during variations caused by sodium depletion.

Blood Platelets↗
PubMed1987

Increased platelet release reaction in 50-year-old men with essential hypertension: correlation with atherogenic cholesterol fractions.

Beta-thromboglobulin (BTG) is a platelet-specific release product. Plasma BTG was significantly increased (p less than 0.01) in 50-year-old, untreated essential hypertensive men (1.22 +/- 0.13 nmol/L, n = 39, mean +/- SE) compared to 50-year-old, healthy normotensive control men (0.82 +/- 0.07 nmol/L, n = 31). Plasma BTG in the hypertensive group correlated significantly with the total serum cholesterol concentration (r = 0.47, p less than 0.01) and with the atherogenic cholesterol fractions low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) cholesterol (r = 0.50, p less than 0.01). In the normotensive group, no significant correlation was observed between plasma BTG and total serum cholesterol (r = 0.14) or between plasma BTG and LDL + VLDL cholesterol (r = 0.08). Neither was any significant correlation found between plasma BTG and serum high-density lipoprotein (HDL) cholesterol or total triglycerides in either group. Thus, middle-aged men with untreated essential hypertension have an increased blood platelet release reaction related to their concentrations of atherogenic blood lipids. This relationship may be of pathogenetic importance for atherogenesis in hypertension.

Blood Platelets↗