| 1. |
- Hvarfner, Andreas, et al.
(författare)
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Interactions between indices of calcium metabolism and blood pressure during calcium infusion in humans
- 1989
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Ingår i: Journal of Human Hypertension. - 1476-5527. ; 3:4, s. 211-220
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Tidskriftsartikel (refereegranskat)abstract
- Calcium plays a central role in maintaining vascular tone. Recent studies indicate that there are continuous relationships between systemic calcium metabolism and BP, as over the whole range of normal and raised BPs there is an inverse correlation between plasma ionised calcium concentration and BP. Twenty-two subjects with normal or moderately elevated BP participated in the present study, undertaken to investigate the interactions between systemic calcium metabolism and BP during a two-hour constant-rate calcium infusion in the absence and in the presence of concomitant verapamil infusion. During the infusion there was an increase in plasma ionised calcium by 0.40 mmol/l, SBP rose by 14 mmHg, and DBP by 9.7 mmHg. Higher basal plasma ionised calcium and lower basal serum parathyroid hormone concentrations were associated with a more pronounced diastolic pressor response to the calcium infusion. A greater DBP increase was also accompanied by more pronounced parathyroid hormone suppression, determined as cyclic adenosine monophosphate excretion, and greater tissue uptake of calcium during the infusion. Conversely, higher basal BPs were associated with greater tissue calcium uptake during the infusions. This relationship was abolished when verapamil was present. The present findings extend the previous observations of continuous relationships between indices of calcium metabolism and BP and indicate that both a direct effect of the calcium ion and indirect effects, as evidenced by cyclic adenosine monophosphate excretion, affect the BP response to acute hypercalcaemia.
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| 2. |
- Ljunghall, S, et al.
(författare)
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Clinical studies of calcium metabolism in essential hypertension
- 1987
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Ingår i: European Heart Journal. - 1522-9645. ; 8:Suppl. B, s. 37-44
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Tidskriftsartikel (refereegranskat)abstract
- Many factors can ultimately lead to an increased blood pressure and it is a generally accepted view that an increase in the active tension of arterioles reflects an increase of the free calcium concentration in the cytosol of the vascular smooth muscle cells. Only recently, however, has the possibility been considered that blood pressure regulation could be influenced by calcium homeostasis. A background for these studies has been provided by the epidemiological observations which link hypertension to a low dietary intake of calcium as well as experimental studies in animals, mostly rats, which have demonstrated that various disturbances of calcium metabolism are related to a raised blood pressure. This review is focused on clinical studies of a possible association between systemic calcium metabolism and the regulation of blood pressure.
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| 3. |
- Pollare, T, et al.
(författare)
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Metabolic effects of diltiazem and atenolol: results from a randomized, double-blind study with parallel groups
- 1989
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Ingår i: Journal of Hypertension. - 1473-5598. ; 7:7, s. 551-559
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Tidskriftsartikel (refereegranskat)abstract
- In a randomized, double-blind study (n = 58) with parallel groups, the effects of diltiazem (mean dose 329 mg/day) and atenolol (mean dose 67 mg/day) on carbohydrate and lipoprotein metabolism in hypertensive patients were compared. The mean systolic blood pressure (SBP)/diastolic blood pressure (DBP) reductions in the supine position were similar and satisfactory, 9/11 and 11/9 mmHg during atenolol and diltiazem treatment, respectively. Insulin-mediated glucose uptake, measured with the euglycaemic insulin clamp technique, decreased during atenolol treatment, from 7.1 to 5.6 mg/kg per min (P = 0.05). but not during treatment with diltiazem (initial value 6.8, final value 6.7 mg/kg per min; P greater than 0.8). Treatment differences between groups were statistically significant (P less than 0.05). During atenolol treatment there was a slight but significant increase in plasma glucose in the fasting state (P less than 0.05) and at the end of an intravenous glucose tolerance test (IVGTT; P less than 0.01), and in plasma insulin at the end of IVGTT (P less than 0.05). Despite increased insulin resistance the increase in insulin response was small, suggesting inhibition of insulin release. The insulin peak was decreased by 13% during diltiazem treatment (P less than 0.05). The concentrations of very-low and low-density lipoprotein triglycerides increased, whereas high-density lipoprotein cholesterol decreased and low-density lipoprotein cholesterol was unaffected during atenolol treatment. In conclusion, there was no difference between the antihypertensive effects of atenolol and diltiazem, but atenolol decreased insulin sensitivity and altered the lipid profile, thus possibly increasing the risk of diabetes mellitus and theoretically reducing the benefits of blood pressure reduction with regard to risk of coronary heart disease.
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| 4. |
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| 5. |
- Hvarfner, Andreas, et al.
(författare)
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Indices of mineral metabolism in relation to blood pressure in a sample of a healthy population
- 1986
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Ingår i: Acta Medica Scandinavica. - 0001-6101. ; 219:5, s. 461-468
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Tidskriftsartikel (refereegranskat)abstract
- Indices of mineral metabolism in blood and urine were analysed in relation to blood pressure in 97 healthy subjects aged 16-82 years. In a multivariate analysis, after allowing for the effects of sex, body mass index (BMI) and age, there was an inverse relationship between plasma level of ionized calcium and mean blood pressure (MBP) (beta = -50.0 mmHg/mmol/l P-ionized calcium, p = 0.0005). In univariate analyses MBP also showed statistically significant inverse relationships with plasma ionized calcium, serum phosphate and renal threshold concentration of phosphate; positive relationships to MBP were found for fasting urinary excretion of calcium and cyclic adenosine monophosphate. However, when examined multivariately, only the relation between MBP and plasma ionized calcium persisted. This study supports previous findings of an inverse relationship between blood pressure and serum ionized calcium and extends the observations to the physiological range. It is further evident from this study that BMI and age should be taken into account in analyses of the relationship between blood pressure and mineral metabolism.
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| 6. |
- Joborn, H, et al.
(författare)
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Serum electrolytes and parathyroid hormone in patients in a coronary care unit
- 1989
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Ingår i: Journal of Internal Medicine. - 1365-2796. ; 225:1, s. 9-14
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Tidskriftsartikel (refereegranskat)abstract
- A prospective study was carried out in 499 patients admitted to a coronary care unit (CCU) in order to evaluate the incidence of clinically significant electrolyte disturbances. Low serum potassium values (less than 3.6 mmol l) occurred in 7% of the CCU patients and low serum magnesium values (less than 0.70 mmol l-1) in 6%. Few patients had low values of both these ions (1.9%). In 49 patients the contents of these electrolytes in muscle biopsies were similar to the values of control subjects and were unrelated to treatment with diuretics. Serum calcium was determined in 444 of the patients and was above the reference range in 11 (2.5%). If we consider their concomitant parathyroid hormone (PTH) values, primary hyperparathyroidism was likely to occur in at least seven patients (1.5%). Patients with acute myocardial infarction (AMI) had mean PTH and electrolyte values similar to those of individuals without this disease. In conclusion, the present study indicates that clinically important disturbances of magnesium, potassium or calcium homeostasis are rare among unselected patients admitted to a CCU.
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| 7. |
- Lind, L, et al.
(författare)
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Long-term treatment with active vitamin D (alphacalcidol) in middle-aged men with impaired glucose tolerance. Effects on insulin secretion and sensitivity, glucose tolerance and blood pressure
- 1989
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Ingår i: Diabetes Research (Edinburgh, Scotland). - 0265-5985. ; 11:3, s. 141-147
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Tidskriftsartikel (refereegranskat)abstract
- There are specific receptors for the active metabolite of vitamin D on the pancreatic beta cells and severe vitamin D deficiency can inhibit insulin secretion. In the present study 14 middle aged men with impaired glucose tolerance and low glucose-stimulated insulin values received 2 micrograms alphacalcidol daily for 18 months. On treatment there was a transient increase of both the peak and the late insulin response to intravenous glucose while neither intravenous nor oral glucose tolerance were consistently altered. Nor was the peripheral insulin sensitivity, measured by the euglycemic clamp technique, significantly affected. In the untreated state there was a positive relationship (r = 0.77) between the tissue insulin sensitivity and the serum concentrations of 25-hydroxyvitamin D. There was also an inverse relationship (r = 0.61) between systolic blood pressure and the serum levels of 1,25-dihydroxy vitamin D. Although the subjects were normotensive and not overweight, treatment with alphacalcidol tended to lower both systolic (6 +/- 12 mmHg) and diastolic blood pressures (5.8 +/- 9.1 mmHg) and there was a small reduction (0.9 kg) in body weight. In conclusion, subjects with impaired glucose tolerance without vitamin D deficiency do not benefit from vitamin D supplementation, which however has some hypotensive action also in normotensive individuals.
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| 8. |
- Ljunghall, S, et al.
(författare)
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Serum electrolytes and parathyroid hormone concentrations in acute myocardial infarction
- 1986
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Ingår i: Experimental and Clinical Endocrinology. - 0232-7384. ; 88:1, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- Serum concentrations of calcium, magnesium, potassium and phosphate can be lowered experimentally by adrenaline, which also can stimulate the secretion of parathyroid hormone (PTH). In order to evaluate the possible clinical importance of these mechanisms serial blood samples were drawn during the first three hospital days in 26 patients with acute myocardial infarction (AMI), a condition known to increase plasma catecholamine levels. During the study period there were no consistent significant changes of the serum electrolytes. The serum PTH levels, however, were significantly raised in the AMI patients already on admission and did not normalize during the observation time. The PTH concentrations were unexplained by infarct size, concomitant diseases or medication. These findings suggest that PTH could be an independent risk factor for AMI.
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