Biomedical subjects

I Eide

Publications and source records attributed to I Eide.

At least 55 records · Page 3Linked to original sources

PubMed1993

Plasma vasopressin, catecholamines and atrial natriuretic factor during hemodialysis and sequential ultrafiltration.

In 13 patients with chronic renal failure on maintenance hemodialysis, plasma vasopressin, atrial natriuretic factor, catecholamines and renin activity were measured during ordinary hemodialysis with fluid removal, and during isolated isoosmotic ultrafiltration and a subsequent isovolemic hemodialysis. Concomitant with a significant fall in serum osmolality, plasma vasopressin decreased significantly from 6.3 +/- 0.8 to 3.8 +/- 0.4 pg/ml (p < 0.05). Predialytic plasma vasopressin was significantly correlated to serum osmolality (r = 0.62, p = 0.001). No such relationship was observed after dialysis. During isolated ultrafiltration (1.25 +/- 0.13 L) through 1 hour, no change in either osmolality or vasopressin was observed, whereas atrial natriuretic factor decreased (700 +/- 136 to 564 +/- 115 pg/ml, p < 0.05). Atrial natriuretic factor was excessively high at all times, and may explain the low plasma renin activity observed in these patients even after fluid removal. No consistent changes were observed in the catecholamines during hemodialysis or ultrafiltration alone, despite marked changes in blood pressure and heart rate. Thus, even in patients with chronic renal failure osmotic regulation of vasopressin seems intact, and volume reduction through ultrafiltration causes a decrease in atrial natriuretic factor.

Arginine Vasopressin↗

PubMed1993

A double-blind, long-term, comparative study on quality of life, safety, and efficacy during treatment with amlodipine or enalapril in mild or moderate hypertensive patients: a multicenter study.

Amlodipine (5-10 mg, once daily) and enalapril (10-40 mg, once daily) were compared in terms of quality of life, efficacy, and tolerability, in a multicenter, double-blind trial lasting for 50 weeks in 461 mild or moderate hypertensive patients. Both drugs were similarly effective in lowering blood pressure while maintaining quality of life. Apart from class-typical effects, such as edema for calcium antagonists, and cough for angiotensin-converting enzyme inhibitors, both drugs were equally well tolerated, with few adverse effects of clinical significance. Only a few patients [eight amlodipine (4%); nine enalapril (4%)] were withdrawn from the trial due to drug-related adverse events, demonstrating that tolerability was good. Neutral to slightly beneficial effects were found in blood lipid concentrations after treatment with amlodipine. Both drugs reduced the calculated risk of coronary heart disease over the next 10 years. It was concluded that amlodipine compared favorably with enalapril as an effective and well-tolerated antihypertensive drug.

Adult↗

PubMed1992

[Treatment of hypertension in the elderly].

The effect of treating hypertension in the elderly (aged 60-65 years and above), and isolated systolic hypertension in particular, has not been adequately documented. In three recent studies, however, a good effect in respect of cardiovascular end points has been observed in this group of patients. We have previously suggested pharmacological treatment of a diastolic blood pressure above 100mm Hg after three to six months' observation and non-pharmacological intervention. In a patient with essential hypertension, and with no concomitant disease, systolic blood pressure should also be taken into account, and when this exceeds (100 + age) mm Hg after the same period of observation the patient should be treated pharmacologically. If a patient shows additional indications for treatment of high blood pressure, the level for initiating treatment may be lower. As of today, diuretics and beta-blockers have proven effective in reducing cardiovascular morbidity and mortality, while data on the other antihypertensive agents are still lacking.

Age Factors↗

PubMed1992

Mild essential hypertension in nonobese premenopausal women is characterized by low renin.

The pathophysiological mechanisms in hypertension may differ in men and women. Plasma renin activity was measured in 27 premenopausal, never-treated hypertensive women (blood pressure 141 +/- 2/93 +/- 1 mm Hg) and in 18 age-matched normotensive women (blood pressure 113 +/- 2/71 +/- 2 mm Hg). All subjects were unaware of their blood pressure status. The hypertensive women had on average lower plasma renin activity (0.21 +/- 0.03 nmol/L/h) than their normotensive controls (0.42 +/- 0.07 nmol/L/h, P less than .01). Serum estradiol was also lower in the hypertensive women (0.57 +/- 0.06 v 0.81 +/- 0.09 nmol/L, P less than .05). No difference in epinephrine, norepinephrine, atrial natriuretic peptide, or vasopressin was found between the groups. Plasma renin activity was positively correlated to plasma norepinephrine in the hypertensive women only (r = 0.41, P less than .05). Since low renin hypertension is associated with less cardiovascular complications, this may offer an explanation for the better prognosis of hypertension in women.

Adult↗

PubMed1992

Effects of hydrocarbons on transformation and intercellular communication in Syrian hamster embryo cells.

The ability of 18 different hydrocarbons to induce and promote morphological transformation and to inhibit intercellular communication in primary Syrian hamster embryo cells in culture have been studied. The compounds were: the n-alkanes octane, nonane, decane, undecane, dodecane and tridecane; the iso-alkanes 2-methylheptane, 2-methyloctane and 2-methylnonane; the naphthenes 1,2-dimethylcyclohexane, 1,2,4-trimethylcyclohexane and tert-butylcyclohexane; the aromates 1,2-dimethylbenzene, 1,2,4-trimetylbenzene and tert-butylbenzene; and the alkenes 1-octene, 1-nonene and 1-decene. None of the hydrocarbons induced morphological transformation of Syrian hamster embryo cells. When the hydrocarbons were incubated together with benzo(a)pyrene, enhancement of the transformation frequency was observed for the naphthene 1,2-dimethylcyclohexane and the iso-alkanes 2-methylheptane and 2-methyloctane. None of the n-alkanes, alkenes or aromates enhanced the transformation frequency induced by benzo(a)pyrene. The alkane tridecane and the iso-alkanes 2-methyloctane and 2-methylnonane reduced intercellular communication in the primary Syrian hamster embryo cells.

Animals↗

PubMed1992

Inhalation kinetics of C6 to C10 aliphatic, aromatic and naphthenic hydrocarbons in rat after repeated exposures.

The toxicokinetic properties of C6 to C10 n-alkanes, aromates and naphthenes have been investigated in rats during inhalation of 100 p.p.m. of the single hydrocarbons for 3 days, 12 hr/day. The concentration of hydrocarbon was measured by head space gas chromatography in blood, brain, liver, kidneys and perirenal fat at days 1, 2 and 3, immediately after termination of exposure and 12 hr after exposure on day 3. The main conclusions drawn from the study were: a) Aromatic hydrocarbons show high concentrations in blood and low concentrations in organs. b) Naphthenic hydrocarbons show low concentrations in blood and high concentrations in organs. c) n-Alkanes show very low concentrations in blood, relatively high concentrations in brain and a high potential for accumulation in fat with repeated exposures. d) Biological concentrations of hydrocarbons within one class increase in general with increasing molecular weight, though with specific exceptions. e) Accumulation is obviously influenced by differences in metabolism and enzyme induction potential. f) Lipid solubility is not the only parameter relevant for the evaluation of hydrocarbon accumulation.

Adipose Tissue↗

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 epinephrine-blood platelet connection with special reference to essential hypertension.

About three decades ago it was shown by an aggregometer that epinephrine activated blood platelets, and it was proposed that platelets could be the link between stress and cardiovascular disease. During the past 10 years this hypothesis has been tested in clinical studies. It has been found that subjects with hypertension consistently have raised plasma catecholamine levels and in particular elevated epinephrine levels. Arterial but not venous epinephrine concentrations correlated with plasma concentrations of the platelet-release reaction marker beta-thromboglobulin (BTG). Plasma BTG is elevated in hypertensive patients, and psychological stress (i.e., hypertension labeling) stimulates plasma epinephrine and BTG. When a physiologic dose of epinephrine is infused into essential hypertensive patients, platelet counts, platelet size, and plasma BTG concentrations increase more than in normotensive subjects. Data suggest that there is a connection between psychological stress, plasma epinephrine levels, and platelet function, especially in patients with essential hypertension.

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

Awareness of high blood pressure stimulates platelet release reaction.

The present study aimed at testing the hypothesis of a link between mental stress and blood platelet function. Twenty-nine 19-year-old men were recruited from the 98th percentile of mean blood pressure (116 mmHg) at a routine medical screening. They were not informed about their elevated blood pressures at the time of the screening. One year later they were randomized into two groups. Group 1 (n = 16) was exposed to mental stress by a letter informing them about their high blood pressure, while group 2 (n = 13) was sent a neutral letter. At an examination 2 weeks later, heart rate (p less than 0.05) and plasma adrenaline (p less than 0.05) responses to a cold pressor test were exaggerated in the informed group. The plasma beta-thromboglobulin (beta TG) concentration was elevated in the informed group (p less than 0.05) as was mean blood pressure (p less than 0.05). beta TG correlated positively with hematocrit (r = 0.59, p less than 0.005) and mean blood pressure (r = 0.43, p less than 0.05), and negatively with plasma HDL (r = -0.61, p = 0.001). The study shows that awareness of hypertension induces a hyperadrenergic state which is associated with the platelet release reaction. Under these circumstances platelet release seems to be correlated to established coronary heart disease risk factors.

Adult↗

PubMed1990

Childhood traumas and psychosocial characteristics of 50-year-old men with essential hypertension.

The aim of the present study was to describe childhood traumas and other psychosocial characteristics of middle-aged men with never-treated essential hypertension. Hypertensive (N = 17) and normotensive (N = 18) 50-yr-old men were selected from the Oslo Study of Cardiovascular Diseases based on their age, sex, blood pressure and otherwise healthy condition without chronic medication. They were interviewed semistructurally by a psychiatrist who was unaware of their blood pressure status. Eleven hypertensives and five normotensives (p less than 0.05) had experienced considerable traumas in childhood, e.g. death of a parent, psychotic parent, separation from one or both parents, or beating by an alcoholic father. The hypertensives had fewer siblings and fewer sons than the normotensives (p less than 0.05). The normotensives were better educated; 12 had finished at least 12 yr in school as opposed to one hypertensive (p less than 0.01). The normotensives' parents (p less than 0.05) and spouses (p less than 0.001) were better educated than the hypertensives'. The normotensives' yearly income was higher (p less than 0.05). The hypertensives showed more Type A behaviour patterns (p less than 0.05) and lower Spielberger State Curiosity (p less than 0.05). Although the groups were small, they were rigorously characterized. These results therefore suggest that middle-aged men with essential hypertension have more childhood traumas and lower educational and income levels and that these social characteristics are associated with Type A behaviour patterns. The study favours a psychosocial understanding of the pathogenesis of essential hypertension.

Arousal↗

PubMed1990

A review of exposure conditions and possible health effects associated with aerosol and vapour from low-aromatic oil-based drilling fluids.

This paper reviews investigations on possible health effects after inhalation of aerosol and vapour from the low-aromatic oil-based drilling fluids which have replaced the diesel-based fluids. The main advantage of the low-aromatic base oils with respect to health hazard is their lower volatility. However, some aliphatic and naphthenic hydrocarbons are distributed more efficiently to the brain than are the corresponding aromatic ones. Reducing the content of aromatic hydrocarbons becomes particularly important when the upper end of the boiling point range is sufficiently high for the base oil to contain carcinogenic polycyclic aromatic hydrocarbons (PAH). As a result of enclosure and local extract ventilation it has been possible to reduce time-weighted average concentrations of aerosol and vapour to below 100 mg m-3. Effects on the central nervous system have only been observed at higher concentrations of the actual hydrocarbons, and male rat hydrocarbon nephropathy is not considered predictive of a normal human response. Insufficient information is available on possible long-term effects of exposure to the low-aromatic oil-based drilling fluids, especially regarding carcinogenicity and changes in the lungs.

Aerosols↗

PubMed1990

Increased arterial adrenaline is related to pain in uncomplicated myocardial infarction.

Plasma levels of catecholamines, beta-thromboglobulin (BTG) and arginine vasopressin (AVP), and degree of pain were examined in 22 patients with suspected uncomplicated myocardial infarction within 24 h following onset of chest pain. Sixteen patients developed infarction with peak creatine phosphokinase at 1280 Ul-1 (range 293-3770 Ul-1). Fifteen healthy men served as controls (C). Arterial adrenaline levels were significantly higher in patients with pain (1.15 +/- 0.23 nmol l-1, n = 8, mean value +/- SEM) than in those without pain (0.60 +/- 0.10 nmol l-1, n = 14, P less than 0.05). Plasma catecholamines were moderately but significantly elevated in myocardial infarction; the concentration of arterial adrenaline was 0.83 +/- 0.14 nmol l-1 and that of arterial noradrenaline was 2.70 +/- 0.28 nmol l-1 compared with 0.44 +/- 0.04 nmol l-1 (P less than 0.025) and 1.47 +/- 0.05 nmol l-1 (P less than 0.0005), respectively, in C. One week later, plasma catecholamines had returned to baseline levels. Plasma BTG showed borderline elevation (1.0 +/- 0.1 pmol l-1) compared with C (0.6 +/- 0.1 pmol l-1, P = 0.04), and remained unchanged 1 week later. Plasma AVP was at baseline level. Uncomplicated myocardial infarction, regardless of size, was associated with only moderately increased sympathetic tone. Plasma adrenaline was related more to the degree of pain than to the presence of acute myocardial infarction. Arterial adrenaline may be a sensitive marker of sympatho-adrenal activity related to pain.

Arginine Vasopressin↗

PubMed1990

Accumulation and distribution of aliphatic (n-nonane), aromatic (1,2,4-trimethylbenzene) and naphthenic (1,2,4-trimethylcyclohexane) hydrocarbons in the rat after repeated inhalation.

The concentrations of the C9 hydrocarbons n-nonane, 1,2,4-trimethylbenzene and 1,2,4-trimethylcyclohexane were measured in rat blood, brain and perirenal fat after exposures to 1000 p.p.m. of the individual compounds. Measurements were made by head space gas chromatography at the end of 12 hr exposures on days 1, 3, 7, 10 and 14 of the exposure periods. The relative concentrations of hydrocarbons in each organ were, brain: n-nonane "trimethylcyclohexane approximately trimethylbenzene, blood: trimethylbenzene "n-C9 greater than trimethylcyclohexane and perirenal fat: trimethylbenzene greater than n-nonane greater than trimethylcyclohexane, showing the widely different distribution properties of the different hydrocarbons. Brain/blood ratios of 11.4, 2.0 and 11.4, and fat/blood ratios of 113, 63 and 135 were found for n-nonane, trimethylbenzene and trimethylcyclohexane, respectively. A marked decrease in biological concentrations of trimethylbenzene and trimethylcyclohexane during the initial phase of exposure indicate that these hydrocarbons are capable of inducing their own metabolic conversion resulting in lower steady state levels. A special attention was made to n-nonane showing the highest concentration in brain concomitantly with a low blood concentration. This observation demonstrate that biological monitoring of occupational exposure by blood measurements not should be performed without knowledge of the distribution properties of the compounds investigated.

Absorption↗

PubMed1989

Effect of beta-adrenergic blockade on hormonal responses during continuous and intermittent exercise.

The modifying effect on exercise performance and neuroendocrine response of the nonselective beta blocker timolol (10 mg b.i.d. for 5 days) and the beta 1-selective beta blocker metoprolol (100 mg b.i.d. for 5 days) was studied. The hormones studied were growth hormone, prolactin, cortisol, renin, epinephrine, dopamine, and norepinephrine. The response was studied during short-term maximal dynamic exercise, using two different exercise protocols; continuous (n = 11) and intermittent (n = 9) bicycle ergometry, in normal healthy young men. Accumulated work on placebo was nearly identical in the two studies, but was significantly reduced by 10.4% and 6.6% with timolol and by 4.7% and 6.7% with metoprolol, during continuous and intermittent exercise, respectively. During continuous exercise, accumulated work was 5.8% lower (p less than 0.05) with timolol than with metoprolol. The hormonal plasma concentrations of all hormones except renin were higher during continuous exercise than during intermittent exercise. Beta blockade had no effect on baseline hormonal levels, but the response was markedly changed during exercise. Maximum epinephrine, cortisol, and prolactin responses increased after beta blockade; dopamine remained nearly unchanged; while the renin responses were attenuated. Norepinephrine concentrations were slightly increased during continuous exercise by beta blockade and rose in direct proportion to the increase in workload. During intermittent exercise, maximum norepinephrine levels were significantly reduced by beta blockade compared with placebo. Thus the effect of beta 1-selective and nonselective beta receptor blockade on circulating hormones does not seem to explain the reduced exercise capacity following beta blockade.

Adrenergic beta-Antagonists↗

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

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↗