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Biomedical subjects

M Fuss

Publications and source records attributed to M Fuss.

At least 73 records · Page 4Linked to original sources

Effect of 1,25-dihydroxyvitamin D3 and nifedipine on prolactin release in normal man.

In normal man 1,25 (OH)2-vitamin D3 [1,25 (OH)2D] increases both basal and TRH-stimulated prolactinemia; this effect is completely reversible by the calcium antagonist nifedipine. Similarly the 1,25 (OH)2D-induced hypercalcemia is totally inhibited by nifedipine. These findings suggest that both biological effects of 1,25 (OH)2D are mediated by calcium-dependent mechanisms.

Adult↗

Magnesium administration reverses the hypocalcaemia secondary to hypomagnesaemia despite low circulating levels of 25-hydroxyvitamin D and 1,25-dihydroxy vitamin D.

The effect of parenteral administration of magnesium was studied in five patients with hypomagnesaemic hypocalcaemia. The initial metabolic state was characterized by a normal level of serum immunoreactive parathyroid hormone (iPTH), and by low or undetectable serum 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25 (OH)2D). A parathyroid response was elicited by the acute intravenous injection of magnesium chloride. In contrast, 1,25(OH)2D did not change up to 24 h after the injection. Intramuscular magnesium sulphate restored serum magnesium and calcium to normal, whereas iPTH was transiently increased. 25OHD remained low and unchanged. 1,25(OH)2D rose very slowly, but the correction of hypocalcemia began before any change in 1,25(OH)2D levels could be demonstrated. Thus, the early correction of hypocalcemia mainly depended on the restoration of an adequate parathyroid function independently of the secretion of 1,25(OH)2D.

25-Hydroxyvitamin D 2↗

Usefulness of 99mTc pyrophosphate bone scintigraphy in the survey of dialysis osteodystrophy.

Fogelman's score (FS) was used to determine the usefulness of 99mTc pyrophosphate (Tc-PP) bone scintigraphy in the evaluation of dialysis osteodystrophy. FS correlated well with bone 47Ca accretion rate. It remained stable after six months in patients treated with 1 alpha (OH)D3 and increased significantly in a randomised group of untreated patients. It decreased after two years of 1 alpha (OH)D3 therapy while serum calcium increased and iPTH and alkaline phosphatases decreased. Patients with low FS, treated by 1 alpha (OH)D3, rapidly developed hypercalcaemia. In cases of spontaneous hypercalcaemia, parathyroidectomy did not normalise serum calcium in patients with low FS despite a significant decrease in serum iPTH. Lower FS were associated with a higher increase in serum aluminium after desferrioxamine (DFO) administration and in two cases of proven aluminium osteomalacia, DFO therapy was followed by a dramatic increase in FS.

Bone and Bones↗

[Familial hypocalciuric hypercalcemia. A new family].

A new example of familial hypocalciuric hypercalcaemia is reported. The family studied consists of 19 members over four generations. The first patient described in this study had already undergone a classical surgical operation for "primary hyperparathyroidism" before the correct diagnosis was established: that of a new syndrome described for the first time by Foley in 1972 and subsequently studied by Marx since 1977. The features of this syndrome are: hypercalcaemia accompanied by hypocalciuria, autosomal dominant transmission with strong penetrance, with early appearance of hypercalcaemia, absence of signs of familial multiple endocrine neoplasia, benign course and persistence of the hypercalcaemia despite classical sub-total parathyroidectomy. Following a family survey, the authors discovered eight other members of the family who also presented this syndrome.

Adult↗

Whole body and regional retention of 99mTc-labeled pyrophosphate at 24 hours: physiological basis of the method for assessing the metabolism of bone in disease.

The retention of 99mTc-labeled pyrophosphate (PPi) at 24 h was measured in 235 patients, 119 of whom had a normal bone metabolism. The mean retention in the group of normal subjects is 52% of the injected dose. Reproducibility of the measurement in a given person is 5.5% coefficient of variation (CV). The value depends strongly on sex (higher in males) and age (higher with increasing age, especially in cortical bone). Retention increases slowly with the decrease in glomerular filtration rate (GFR) between 50 and 120 ml/min; it rises very rapidly with values below 50 ml/min. The slowing down of the GFR with age does not account for the increase in PPi retention with age. When expressed as a percentage of the expected value for sex and age, retention is frequently low in osteoporosis (P less than .001), more so when urinary hydroxyproline is low; it is normal or high in osteomalacia, and in some cases rises after vitamin D treatment is started; it is high in hyperparathyroidism (P less than .01). The PPi retention is correlated with bone calcium accretion rate, alkaline phosphatase level, and above all, the urinary hydroxyproline level. The lower the bone mineralization (Ca/hydroxyproline ratio in biopsy), the higher the retention value. We conclude that the PPi retention is an index of bone metabolism when GFR is higher than 50 ml/min. It allows for classification of metabolic bone diseases according to the bone turnover rate. It has the advantage over the usual biologic examinations in that it affords better observation of highly localized bone disorders and can be used in combination with a morphologic record, the bone scintigraphy.

Adolescent↗

Comparison between the fractional isotopic calcium absorption and an oral calcium tolerance test.

In 27 subjects with several disorders of calcium metabolism, the fractional intestinal absorption of 47CaCl2 was rather poorly correlated with the urinary output of calcium or with the maximal increase of serum calcium after an oral calcium load. Conversely, a good correlation was observed with the product of these parameters. We propose that this product be used as an estimate of intestinal calcium absorption when a radioisotopic method is not available.

Calcium↗

Bone mineral content in idiopathic renal stone disease and in primary hyperparathyroidism.

Bone mineral content (BMC) was measured with the Norland Cameron apparatus in 120 renal stone formers (RSF) with idiopathic stone disease and in 41 patients with primary hyperparathyroidism. RSF were classified, according to an oral calcium load test, into three groups: no hypercalciuria (HC; 41 cases); absorptive HC (53 cases), and resorptive or renal HC (25 cases). BMC values in RSF as a group were significantly lower than normal (p less than 0.001, Mann-Whitney test) though higher than in hyperparathyroid patients. There was a trend for BMC to decrease from male RSF without HC to patients with renal or resorptive HC. No statistical difference was found between the groups, however, BMC values in absorptive HC were different from normal (p less than 0.001). Why patients with HC are demineralized is unclear since no correlation was found between BMC and basal values of serum phosphate, TRP, calculated TmP/GFR, urinary calcium or hydroxyproline. Nevertheless our results indicate that urolithiasis, and possibly its treatment, is not a benign condition for the skeleton.

Bone and Bones↗

Predictive value of 99mTc pyrophosphate bone scintigraphy for vitamin D trials in uraemia.

The usefulness of 99mTc-Pyrophosphate (99mTc-PPi) bone scintigraphy was evaluated in the follow up of 21 haemodialysed patients without clinical or radiological evidence of osteodystrophy. 99mTc-PPi bone scintigraphy was semi-quantitatively analysed using Fogelman's score. Patients were randomised to receive vitamin D analogues (1 alpha hydroxyvitamin D3 or dihydrotachysterol, n = 12) or to serve as controls (n = 9), both groups being given oral calcium supplements. Bone scintigraphy deteriorated in patients only on calcium therapy but not in patients treated by vitamin D-analogues. Vitamin D therapy reduced secondary hyperparathyroidism in all cases but induced rapid intoxication with normal doses in 4 of the 12 treated patients. Since intoxicated patients had significantly lower Fogelman's score than the patients who tolerated the treatment well, 99mTc-PPi bone scintigraphy is proposed as a screening test before vitamin D-analogues trials.

Bone and Bones↗