[Drugs exist--but changing of life style can be sufficient in the prevention of osteoporosis].
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Aged↗
Biomedical subjects
S Ljunghall
Publications and source records attributed to S Ljunghall.
Delayed hypersensitivity in primary and secondary hyperparathyroidism. Treatment with active vitamin D.
The vitamin D endocrine system, besides its traditional role in mineral metabolism, also affects the immune system. A recent study demonstrated that vitamin D supplementation restored a blunted delayed hypersensitivity response (DH) in elderly vitamin D-deficient subjects. In the present study the DH, as measured by the tuberculin test (PPD), was studied in two groups of patients with a disturbed vitamin D system, i.e. primary hyperparathyroidism (HPT) and secondary HPT due to chronic renal failure. A significant reduction in DH was found in the patients with chronic renal failure when compared to control subjects (4.1 +/- 5.3 vs 12 +/- 9.3 mm, p less than 0.05) whereas only a non-significant tendency to a reduced DH was seen in the HPT patients (9.5 +/- 9.2 mm). Treatment with alphacalcidol, a synthetic analogue to the active vitamin D metabolite over 3-6 months did not affect the DH in any of the hyperparathyroid patient groups. Thus it seems likely that other factors than vitamin D were involved in their reduced DH response.
Calcitriol↗
Indices of mineral metabolism in subjects with an impaired glucose tolerance.
An altered mineral metabolism has been described both in insulin dependent and non-insulin dependent diabetes mellitus. In order to investigate if a disturbed mineral homeostasis was an early feature in the development of diabetes, 52 middle-aged men who all had recently developed an impaired glucose tolerance (IGT) were compared to healthy control persons. The IGT subjects showed higher levels of serum calcium (2.38 +/- 0.081 mmol/l (SD) vs 2.35 +/- 0.065 in controls) but similar levels of plasma ionized calcium indicating an increased protein binding of serum calcium in IGT. Serum magnesium was significantly lower in the IGT subjects (0.79 +/- 0.060 mmol/l vs 0.85 +/- 0.065, p less than 0.001) while serum phosphate was unaltered. This study demonstrates indices of an impaired mineral metabolism in IGT subjects similar in characteristics to what has previously been reported in manifest diabetes mellitus suggesting that an alteration of mineral homeostasis could be part of a primary event.
Electrolytes↗
Calcium metabolic indices, vascular retinopathy, and plasma renin activity in essential hypertension.
The interplays between calcium metabolic indices, retinal vascular status, plasma renin activity and blood pressure were examined in 67 patients with untreated essential hypertension. There was an inverse relationship between plasma ionized calcium and blood pressure (P = .002), whereas albumin-modified total serum calcium was directly related to blood pressure (P = .02). The plasma cyclic AMP level (P = .05) and the 24 h urinary excretion of cyclic AMP (P = .03) were also positively associated with blood pressure. Patients with vascular retinopathy had lower plasma ionized calcium concentrations (P = .01) and higher 24 h urinary cyclic AMP excretions (P = .05) than those without such changes, even when the differences in blood pressure, age, sex and body mass index were taken into account in analyses of covariance. Plasma renin activity did not interfere with the relationships between calcium metabolic indices and blood pressure, nor were there any associations between the renin status and the calcium metabolic indices. These findings suggest that a low concentration of plasma ionized calcium is an independent risk factor for vascular disease.
Adult↗
Impaired secretion of parathyroid hormone in patients with rheumatoid arthritis: relationship to inflammatory activity.
Hypocalcaemic tests, employing infusion of EDTA over 1 h, were performed in 22 patients with rheumatoid arthritis (RA) and 14 healthy controls. The basal levels of calcium and parathyroid hormone (PTH) were not significantly different in the two groups. The RA patients displayed a markedly impaired PTH response during infusion of EDTA compared with the controls although the reduction of plasma ionized calcium was similar. The PTH response was furthermore significantly, inversely, related to the inflammatory activity measured as sedimentation rate (r = 0.65; P less than 0.01), i.e. the more pronounced the inflammation, the less the capacity to secrete PTH. Since secretion of PTH is related to the intracellular calcium concentration of the parathyroid cells, these findings are in line with previous observations of a higher intracellular calcium content in inflammatory disease. They also support the earlier indications of reduced bone turnover in inflammatory arthritides. An insufficient parathyroid function could be one factor contributing to bone disease in these conditions.
Acute-Phase Reaction↗
Hyperoxaluria or hypercalciuria in nephrolithiasis: the importance of renal tubular functions.
The role of the kidney in states of hyperoxaluria and hypercalciuria was investigated in seven patients with hyperoxaluria after jejunoileal bypass (JIB) and six patients with idiopathic hypercalciuria (IHC). Eight apparently healthy persons formed a control group. Besides hyperoxaluria, the patients with JIB displayed an elevated plasma concentration of oxalate and the oxalate clearance was increased and higher than creatinine clearance, indicating a net tubular secretion of oxalate. The JIB patients had lower 24-h urinary excretions of calcium, phosphate, magnesium and citrate and higher serum parathyroid hormone (PTH) than controls, indicating increased secretion of PTH to compensate for calcium malabsorption. IHC patients exhibited increased fasting urinary calcium even though their serum values were similar to those in the controls. These results indicate a reduced tubular calcium reabsorption, which was most pronounced in patients with highest PTH values. We conclude that hyperoxaluria in JIB patients is associated both with intestinal hyperabsorption and with enhanced tubular secretion of oxalate, and that in some patients with IHC hypercalciuria is due to reduced tubular reabsorption of calcium.
Adult↗
Effects of prolonged adrenaline infusion and of mental stress on plasma minerals and parathyroid hormone.
The role of the sympatho-adrenal system for the secretion of PTH in humans is not established. Previous studies on the effects of adrenaline on plasma mineral homeostasis have focused on injections or short-term infusions of adrenaline, and conflicting results concerning calcium and parathyroid hormone (PTH) responses have been reported. We therefore infused adrenaline or placebo continuously for 3 h to 10 healthy volunteers and studied several plasma minerals, as well as PTH levels. Venous plasma adrenaline concentrations increased to the upper physiological range (5 nmol l-1) during adrenaline infusion. Another nine volunteers were exposed for 25 min to mental stress (a colour word conflict test; CWT), which causes marked circulatory changes and raises plasma catecholamine concentrations. Plasma ionized and total calcium, and magnesium concentrations were slowly and gradually reduced during infusion of adrenaline, but there was only a small increase in PTH. Plasma potassium was decreased by adrenaline within 30 min and thereafter did not change further during infusion. There was a marked but transient increase in the plasma free fatty acids concentration, which were not related to the reduction of the calcium or magnesium levels. The adrenaline-induced decrements in calcium, magnesium and potassium, and increases in heart rates persisted 30 min after the infusion, despite a rapid decrease in plasma adrenaline concentrations within 5 min of termination of the infusion. Plasma phosphate concentrations were lowered during the first 90 min of adrenaline infusion, but after 3 h they had returned to baseline despite continued infusion. CWT induced small increments of the plasma ionized calcium and PTH concentrations. Plasma potassium levels were raised despite increases in plasma adrenaline at the beginning of the stress test, while phosphate values were reduced at the end of the test. Thus, long-lasting elevations of circulating adrenaline lower plasma ionized and total calcium, phosphate, magnesium and potassium, but the time courses for these changes differed markedly. Despite the reduction of plasma ionized calcium there was only little increase in PTH and thus no indication that sustained elevations of circulating adrenaline stimulates the secretion of PTH in vivo in humans. Responses to acute mental stress and adrenaline infusion differed qualitatively, indicating that adrenaline responses to stress are of minor importance in this respect.
Adult↗
Effects on serum parathyroid hormone of intravenous treatment with alphacalcidol in patients on chronic hemodialysis.
Secondary hyperparathyroidism is common in chronic renal failure and is due to inadequate synthesis of calcitriol, the active metabolite of vitamin D. Intravenous administration of alphacalcidol, a synthetic analogue which is metabolized to calcitriol, was given during 12 weeks to 51 patients on chronic hemodialysis in doses between 1 and 4 micrograms/dialysis session. The treatment caused a modest rise, by 0.25 mmol/l, in serum calcium but a 60% reduction of intact serum PTH concentrations. Most patients acquired normal PTH values and hypercalcemia was easily avoided by dose adjustments. There was a significant reduction in serum PTH within the 1st week before the serum calcium concentrations were increased, but after that time the induced suppression of PTH was correlated to the induced rise in serum calcium. These observations are compatible with the view that calcitriol exerts both a direct inhibition of PTH release and increases the gland's sensitivity to calcium. The major implication of the study is that intravenous treatment with alphacalcidol is of great clinical value since it is easy to administer and provides suppression of hypersecretion of PTH with few side effects.
Aluminum↗
Platelet and plasma catecholamines in relation to plasma minerals and parathyroid hormone following acute myocardial infarction.
Epinephrine has been shown to lower the plasma concentrations of several minerals and elevate those of parathyroid hormone (PTH). In order to evaluate the possible clinical importance of such experimental observations, 34 patients with acute myocardial infarction (AMI) were studied with daily determinations of plasma catecholamines, minerals, and PTH during the first week after AMI and at follow-up one month later. In addition, platelet catecholamines were determined as they fluctuate more slowly than plasma catecholamines. After infarction initial platelet epinephrine and norepinephrine levels were higher (p less than 0.05 for both) in nonsurvivors than survivors during a one year follow-up. Results suggested that activation of the sympathoadrenal system influences calcium homeostasis following AMI, but that the impact of sympathoadrenal activation on mineral metabolism is of minor clinical significance in the average AMI patient. High platelet catecholamine levels may predict a poor outcome after AMI.
Adrenal Medulla↗
Hypercalcemia in pulmonary tuberculosis.
Tuberculosis can affect calcium metabolism, mainly through an enhanced production of active vitamin D. The incidence of hypercalcemia among unselected patients with active pulmonary tuberculosis was investigated, retrospectively, during a ten-year period. Among 67 patients, the mean serum calcium concentration on admission was significantly raised compared to healthy controls (2.51 +/- 0.16 (SD) vs 2.43 +/- 0.07 mmol/l; p less than 0.001) and 25% of the patients had hypercalcemia. After one year of successful tuberculostatic treatment the serum calcium values had normalized.
Aged↗
Clinical and experimental advances in sporadic primary hyperparathyroidism.
Primary hyperparathyroidism (HPT) has shown prevalence of up to 3% among elderly women in Nordic health screening surveys, and is increasingly diagnosed in patients with diffuse neuromuscular or psychiatric symptoms. Primary HPT, even with mild hypercalcemia, is associated with increased mortality risk, mainly from cardiovascular disease. Despite the efficacy of new methods, reliable histopathologic distinction between adenomatous and hyperplastic parathyroid disease may still be difficult, and indeed circumstantial evidence suggests that adenoma and chief cell hyperplasia are not always distinctly separate pathophysiologic entities. Irrespective of symptoms, the hyperplasia is associated mainly with mild to moderate hypercalcemia, and may thus constitute an early form of HPT. A more liberal attitude to surgery in primary HPT would increasingly extend treatment to less clear-cut cases. The demonstration by monoclonal antiparathyroid antibodies of a specialized calcium receptor mechanism on the surface of parathyroid cells and its reduced expression in pathologic parathyroid tissue seems to explain defective parathyroid cell function and ensuing hypercalcemia in HPT. These antibodies appear to offer new prospects in parathyroid histopathology and research.
Antibodies, Monoclonal↗
Clinical characteristics and surgical treatment of sporadic primary hyperparathyroidism with emphasis on chief cell hyperplasia.
In 570 patients with sporadic primary hyperparathyroidism, the age, sex, symptoms, and preoperative serum calcium values were related to the histopathologic diagnoses, operative findings, and the extent and outcome of parathyroid surgery. Renal stone formation was especially prevalent in younger patients with slight hypercalcemia and parathyroid chief cell hyperplasia, whereas neuromuscular and psychiatric disturbances were overrepresented among older women with higher serum calcium values. Serum calcium concentration was inversely correlated to the proportional incidence of chief cell hyperplasia and positively correlated to the glandular weight of both adenomas and hyperplasias. Glandular size was markedly irregular in chief cell hyperplasia, with increased gland weights of no more than two glands in 78% of patients. During follow-up, for as long as 27 years, normocalcemia was obtained in 91% of patients with adenomas, with failures mainly depending on difficulties in identifying the parathyroid glands. The rate of normocalcemia was lower (80%) among patients with hyperplasia, but an inability to visualize the glands was not a major cause of failure. In patients with hyperplasia with asymmetric and more markedly enlarged glands, it appeared sufficient to remove only the enlarged glands, whereas the findings advocated a subtotal 3- to 3.5-gland resection in patients with more symmetrically or less enlarged hyperplastic glands.
Adenoma↗
Treatment of enteric hyperoxaluria with calcium-containing organic marine hydrocolloid.
An organic marine hydrocolloid (OMH) charged with calcium ('Ox-Absorb') was studied in vitro for oxalate binding and in patients with enteric hyperoxaluria to investigate oxalate excretion and the inhibitory activity on crystal formation of the urine. In-vitro experiments showed complete binding of oxalate to OMH. In clinical studies in nineteen patients with intestinal disorders and stone formation, urinary oxalate excretion was significantly lower during OMH treatment than off treatment. The activity product index of calcium oxalate was reduced on treatment. A pronounced rise in the inhibitory activity of urine was seen in two patients with very low pretreatment values. Most patients experienced virtual normalisation of bowel function, and in those with severe stone formation there was substantial clinical improvement. It is concluded that OMH has the capacity to bind oxalate in vitro and to reduce urinary oxalate excretion. These observations suggest a new promising treatment for enteric hyperoxaluria.
Administration, Oral↗
[Bone mass, osteoporosis and fractures--what do heredity and environment mean?].
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Adult↗
[Hypertension as a systemic metabolic disease].
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Blood Glucose↗
[Hypercalcemia and skeletal engagement in malignancy--development and therapeutic possibilities].
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Bone Neoplasms↗
Binding of glycosaminoglycan inhibitors to calcium oxalate crystals in relation to ionic strength.
Several inhibitors of calcium oxalate crystallization have been identified and shown to exhibit quantitative and qualitative differences in efficacy. Glycosaminoglycans are potent inhibitors of crystal growth and aggregation, and the efficiency seems to increase with an increasing charge density. In order to investigate the mechanism of inhibition, we performed binding experiments of radioactivity labelled heparin, chondroitin sulphate and the low-molecular mass heparin analogue pentosan polysulphate to calcium oxalate crystals and subsequent displacements by increasing the amounts of non-radioactive ligands or increasing ionic strength. Ligands with a high charge density bound more readily and with a seemingly higher affinity than ligands with a low charge density, but were also more susceptible to displacement when the ionic strength was increased. It is concluded that a higher affinity to the crystals may be the reason why highly charged glycosaminoglycans are more efficient inhibitors of calcium oxalate crystal growth.
Calcium Oxalate↗
Muscle function in patients with primary hyperparathyroidism.
The muscle contraction of the anterior tibial muscle was investigated by measurements of electrically stimulated and computer-analyzed muscle twitches in 18 unselected patients with primary hyperparathyroidism (HPT) and in 20 healthy control persons. The HPT patients had a lower muscle twitch tension (TT) at single stimulation, compared with the control group [76 +/- 24 N (SD) and 99 +/- 33 N respectively, P less than 0.05]. At high-frequency stimulation the difference in muscle force increased, and at 20 Hz stimulation the force in the HPT patients was 73% of that in the controls (P less than 0.01). There were no differences between the HPT patients and the control persons in neither contraction time nor half relaxation time at single muscle twitch nor in twitch potentiation after 20 and 90 seconds maximal voluntary contraction. The results indicate that patients with primary HPT have an impaired muscle function of probable importance for their symptoms of weakness and generalized fatigue.
Adult↗