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Biomedical subjects

S Ljunghall

Publications and source records attributed to S Ljunghall.

At least 271 records · Page 15Linked to original sources
PubMed1987

Treatment with clodronate in patients with hypercalcemia secondary to malignancy.

Dichloromethylene bisphosphonate (clodronate, Cl2MDP) is a synthetic analogue to pyrophosphate, which inhibits increased bone resorption. This drug was given to 12 patients with hypercalcemia secondary to advanced malignant disease. Clodronate in a daily dose of 1.6 to 3.2 g generally caused a return of the serum calcium values to normal within 5-10 days with a concomitant improvement of symptoms related to the hypercalcemia. Side effects were few. Thus, clodronate appears to be a valuable adjunct for the medical management of patients with malignancy-associated hypercalcemia.

Adult↗
PubMed1987

Comparative effects of calcitonin and clodronate in hypercalcaemia.

Both calcitonin and clodronate inhibit bone resorption and have therefore been used as therapy for malignancy-associated hypercalcaemia. In order to evaluate their effects a compilation was made of data from 78 patients receiving oral or intravenous clodronate which was compared with a previous review of the effects of calcitonin. Both drugs induced significant reductions of serum calcium but the decrease was greater with clodronate, particularly when given intravenously. Whereas the response to calcitonin generally was of short duration, clodronate was capable of maintaining normal serum calcium values over several weeks with oral administration. Thus, from the clinical point of view clodronate is a very useful adjunct to the available therapy, but the limited experience so far has not fully outlined its position in the management of patients with hypercalcaemia.

Administration, Oral↗
PubMed1987

Incidence of upper urinary tract stones.

During the last few decades there has been a steady rise of the incidence of upper urinary tract stones in the industrialized countries. Dietary factors, mainly an increased consumption of animal protein, probably explain part of this dramatic change. Little is, however, known how other components of the altered life styles might affect the propensity for stone formation. The prevalence of renal stones, as obtained in postmortem or radiographic studies, is 1-3% without apparent sex differences. In several unselected population surveys the life time risk for males approaches 20% while for females it is 5-10%. The recurrence rate is high and around 50% will experience another stone within 5 years from the onset. The annual incidence is around 1% in males with a peak in the fifth decade. Thus upper urinary tract stones are much more common than is generally appreciated, but most studies of their pathophysiology are only concerned with the small fraction of patients that is investigated in specialized research clinics.

Hospitalization↗
PubMed1987

Mortality after surgery for primary hyperparathyroidism: a follow-up of 441 patients operated on from 1956 to 1979.

Four hundred forty-one patients who were operated on for primary hyperparathyroidism were observed for up to 22 years. Mortality was significantly higher than expected during the first postoperative years, for both men and women. This was predominantly due to a higher than expected incidence of diseases of the circulatory organs. The greater risk of death--compared with the expected mortality in the general patient population--appeared to decrease after the initial 5 to 8 postoperative years. However, for the entire follow-up period, the cumulative survival ratio (i.e., the ratio between the expected and the observed rates) was less than 1 for both sexes. The preoperative concentration of serum calcium did not influence the survival rates. The findings are consistent with the hypothesis that untreated hyperparathyroidism carries an increased risk of death, particularly from cardiovascular diseases but that this risk is gradually reduced after surgery.

Actuarial Analysis↗
PubMed1987

Relationships between calcium metabolic indices and blood pressure in patients with essential hypertension as compared with a healthy population.

Relations between indices of mineral metabolism and blood pressure were examined in 182 subjects, comprising 58 patients with essential hypertension (EHT) and 124 healthy subjects attending a general health survey. Multivariate techniques of statistical analysis were employed to test the hypothesis of different relationships between blood pressure and calcium metabolism within the subpopulations and to eliminate confounding effects of age, sex and obesity. Plasma ionized calcium was inversely related and the urinary calcium excretion positively related to blood pressure in the total group. This was not significantly different between the groups. Serum parathyroid hormone (PTH) was, however, related to diastolic blood pressure only in the EHT group. The EHT patients had significantly lower plasma levels of ionized calcium, significantly higher levels of PTH and significantly greater excretion of calcium in the urine than the healthy subjects. The results of this investigation support the hypothesis that among patients with EHT the renal tubular reabsorption of calcium is impaired resulting in a reduction of plasma ionized calcium and thereby stimulation of PTH. The findings of linear relationships suggests the possibility of a direct association between calcium metabolism and the regulation of blood pressure.

Adult↗
PubMed1986

Dual effects of a new hypocalcemic agent, WR-2721, on cytoplasmic Ca2+ and parathyroid hormone release of dispersed parathyroid cells from patients with hyperparathyroidism.

The effects of the new hypocalcemic agent, WR-2721, on calcium-regulated parathyroid hormone (PTH) release, cytoplasmic Ca2+ (Ca2+i) and membrane potential were measured in dispersed parathyroid cells from patients with hyperparathyrodisim (HPT). The drug had no effects in the absence of extracellular Ca2+ but acted synergistically with Ca2+ in the 0.5-1.5 mM range by depolarizing the cells, increasing Ca2+i and inhibiting PTH release. Although the depolarizing effect of 3.0 mM Ca2+ was unaffected by WR-2721 the drug antagonized the effect of Ca2+ by decreasing Ca2+i and stimulating PTH release. Whereas the inhibitory actions of WR-2721 on PTH release may result from the activation of the mechanism for Ca2+ gating in the parathyroid cell plasma membrane, the stimulatory effect probably reflects increased intracellular Ca2+ sequestration. The drug is considered potentially important for the treatment of HPT.

Amifostine↗
PubMed1986

Crystal inhibition: the effects of polyanions on calcium oxalate crystal growth.

The inhibition of calcium oxalate crystal growth by the glycosaminoglycans, chondroitin sulphates and heparin, by the low-molecular-weight heparin analogue pentosan polysulphate and by Tamm-Horsfall glycoprotein extracted from human urine, was measured by using a seeded crystal procedure and compared with the inhibition by pyrophosphate. It was found that the most pronounced inhibition was obtained with the polyanions with the highest charge density, i.e., heparin and pentosan polysulphate. Tamm-Horsfall glycoprotein caused an inhibition of a similar magnitude as urinary chondroitin sulphates. Urinary polyanions with a high affinity to Sepharose 4B were more efficient inhibitors than those with a low or no affinity to the gel. It is concluded that urinary polyanions are important inhibitors of calcium oxalate crystal growth and that the potency of inhibition increases with the charge density.

Anions↗
PubMed1986

Normalizing effect of Ca2+ ionophore on cytoplasmic Ca2+ and parathyroid hormone release of dispersed parathyroid cells from patients with hyperparathyroidism.

The effects of the Ca2+ ionophore A23187 on parathyroid hormone (PTH) secretion and cytoplasmic free Ca2+ concentration (Ca2+i) were measured at different extracellular Ca2+ concentrations using dispersed cells from patients with hyperparathyroidism (HPT). The addition of a low concentration of the Ca2+ ionophore to quin2-loaded cell preparations resulted in the apparent normalization of calcium-regulated Ca2+i. At all extracellular calcium concentrations Ca2+i reached significantly higher values in the presence of the ionophore and the dose-response relationship was shifted to the left. Under similar conditions calcium-regulated PTH release was correspondingly corrected with an increased suppressibility and left-shifted dose-response relationship. The data render strong support for a disturbed regulation of Ca2+i as a major factor in the pathophysiology of HPT.

Aminoquinolines↗
PubMed1986

Histologic parathyroid abnormalities in an autopsy series.

The parathyroid glands from 422 subjects without clinical, biochemical, or advanced histologic signs of renal disease were dissected at autopsy. The glands were evaluated histologically in relation to the subjects' age, sex, histologic renal features, other diseases, and medical therapy. Normal parathyroid glands generally had diffuse cellular arrangements, with variable fat cell content. Increased nodularity was observed, especially in enlarged parathyroid glands. Hyperplasia was present in 7 per cent and adenomas in 2.4 per cent. Hyperplastic glands were often nodular and asymmetric, and numbers of oxyphil cells were frequently increased. Some large nodules were histologically indistinguishable from adenomas. Serum calcium levels were elevated in subjects with adenomas or with hyperplastic glands containing large nodules. The findings seem to indicate that nodularity of the parathyroid tissue is a sign of abnormality and that adenomas may arise from such nodular hyperplasia. Hyperplasia and adenomas were more common in elderly subjects and in those with slight or moderate nephrosclerosis. Other diseases or medical therapy were not found to be correlated with parathyroid weight or histologic features.

Adolescent↗
PubMed1986

Binding of glycosaminoglycans to sodium urate and uric acid crystals.

The binding of heparin, chondroitin sulphate and the low molecular weight heparin analogue pentosan polysulphate to sodium urate and uric acid crystals was studied by the use of radioactively labelled glycosaminoglycans were used in the binding step, and varying amounts of unlabelled glycosaminoglycans for the competition experiments. The experiments were carried out in 140 mmol/l NaCl at pH 6, with or without 5 mmol/l CaCl2 in the solution. A reversible and almost complete binding of heparin and chondroitin sulphate to sodium urate crystals did occur in the presence of calcium, whereas pentosan polysulphate bound incompletely. The binding was much less pronounced in the calcium-free conditions. Uric acid crystals did not bind any of the three inhibitors, not even with calcium present. The clinical relevance depends on whether sodium urate microcrystals are present in the urine of calcium stone patients, to cause a binding and thereby a masking or inactivation of these inhibitors in the urine, which seems to be possible in the presence of calcium. However, the potential of pentosan polysulphate for the treatment of calcium stone patients does not seem to be at risk from this effect.

Binding, Competitive↗
PubMed1986

Serum electrolytes and parathyroid hormone concentrations in acute myocardial infarction.

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.

Calcium↗
PubMed1986

Primary hyperparathyroidism in patients with organic brain syndrome.

In a retrospective study of 552 patients operated on for primary hyperparathyroidism (HPT) the effects of parathyroid surgery were selectively investigated in 13 elderly patients with organic brain syndrome. With a few exceptions, these 13 patients had mild or moderate hypercalcaemia but severe mental impairment. Ten patients had a clinical diagnosis of senile dementia and 12 had been admitted from a mental hospital. Postoperatively, eight patients improved mentally and seven of them were able to return to their homes or could be transferred to somatic units. The eight patients who showed improvement, either temporary or more permanent, had a relatively short duration of mental symptoms preoperatively, all less than 2 years, while those who did not improve mentally after surgery had a longer history of mental illness. Screening for HPT was subsequently performed in a psychogeriatric clinic to investigate the prevalence of HPT in this population. Hypercalcaemia and probable HPT was found in five (5%) of 101 patients. The results indicate that parathyroidectomy may improve the mental state in patients with HPT and organic brain syndrome. As a substantial number of patients in a psychogeriatric population seem to have HPT, the disease should be searched for in patients with newly diagnosed organic brain syndrome.

Aged↗
PubMed1986

Indices of mineral metabolism in relation to blood pressure in a sample of a healthy population.

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.

Adolescent↗
PubMed1986

Prolonged low-intensity exercise raises the serum parathyroid hormone levels.

Twelve healthy males performed 5 h exercise on a bicycle ergometer at a constant work load of approximately 50% of their maximum capacity. The serum concentrations of parathyroid hormone (PTH) increased after the first hour and were continuously elevated throughout the exercise period. The rise in PTH was 5-7% above pre-exercise levels, corresponding to 20-30% of the maximal increase obtained by the same assay during prolonged hypocalcaemia. The probable cause for the rise in PTH was that the plasma ionized calcium tended to be lowered during exercise. Since the total serum calcium concentrations were raised (by 3-5%) during exercise the reduction of the free, ionized, fraction was presumably largely due to increased complex-binding although an outward transport from plasma was not excluded. The serum concentrations of magnesium were gradually reduced during exercise while those of phosphate and potassium were raised throughout, probably as a result of leakage from the working muscle.

Adult↗
PubMed1986

Enzymatic determination of urinary chondroitin sulphate: applications in renal stone disease and acromegaly.

A method was developed for the determination of urinary chondroitin sulphate (CS), including dermatan sulphate and chondroitin 4 and 6-sulphates, using an enzymatic degradation with chondroitinase-ABC followed by precipitation with Alcian blue, whereby CS was determined as the difference between undigested and chondroitinase digested material. The method was linear in the range 0-100 mg l-1 with a detection limit of 1 mg l-1 and allowed determinations on small urine volumes without pretreatment of the urine. It could be demonstrated that males excreted more CS than females, and growing children had the highest urinary content of CS. Renal calcium stone formers did not differ from healthy controls in urinary CS. Patients with acromegaly had a higher excretion of CS compared with controls. There was also, in these patients, a positive correlation between the serum growth hormone levels and the urinary CS, indicating that CS-excretion may be an estimate of the activity of the pituitary disorder.

Acromegaly↗
PubMed1986

Alteration in density, morphology and parathyroid hormone release of dispersed parathyroid cells from patients with hyperparathyroidism.

Dispersed parathyroid cells from normal human and bovine glands and from 10 patients with primary (7 adenomas, 3 hyperplasias) and 4 patients with uraemic hyperparathyroidism (HPT) have been investigated with respect to density, morphology and parathyroid hormone (PTH) release. Percoll density gradients enabled an efficient isolation of viable parathyroid cells which generally banded between 1.035-1.090 g/ml. The average density was significantly higher in cells from the normal than the abnormal glands. The pathological glands contained large chief cells, oxyphil and transitional oxyphil cells and, in one case, water-clear cells which were enriched in fractions with densities below 1.055 g/ml. Measurements of cell diameters revealed an increased proportion of enlarged cells in the preparation of abnormal glands. Nuclear diameters were similar in the normal human glands, adenomas and hyperplasias, but the variability was greater among the adenomas. In comparison to normal bovine parathyroid cells, PTH release of cells from the pathological human glands was reduced and abnormally insensitive to extracellular calcium. The oxyphil and water-clear cells secreted similar amounts of PTH as the chief cells of the abnormal glands. The disturbed PTH release in secondary HPT seemed to be confined mainly to cells within nodules of the hyperplastic glands. The results show that the disturbed hormone regulation in HPT is related to morphological changes of the cells and that buoyant density gradients can be used to accumulate the abnormal cells.

Adenoma↗