Jacques Corvilain

Involvement of low-calcium diet in the reduced bone mineral content of idiopathic renal stone formers

SummaryThe possibility that low-calcium intake in renal stone formers could lead to reduced bone mineral content was investigated in 123 male patients with idiopathic urolithiasis. Radius bone mineral content, (BMC) was measured by single photon absorptiometry. Two groups of patients were analyzed: group 1 (n=63) maintained on a free diet; group 2 (n=60) maintained on a low-calcium diet (350 mg/day ±20 SEM) for 3.9 years ±0.6 SEM. The two groups of patients were investigated after a standard reduction of calcium intake for at least 1 week. The urinary excretion of calcium and of hydroxyproline, and the serum alkaline phosphatase activity were higher in both groups than in normal subjects submitted to the same low-calcium diet. Both groups of stone formers showed lowered radius BMC values at 3 cm (distal) and 8 cm (proximal) above the styloid process, but distal BMC was significantly lower in group 2 than in group 1. The results suggest that low-calcium intake could worsen the already decreased BMC of idiopathic renal stone formers.

Calcium and vitamin D metabolism in granulomatous diseases

SummaryOverproduction of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.

Expression of mRNA of parathyroid hormone-related peptide in fetal bones of the rat

SummaryPrevious studies have indicated that 19-dayold fetal long bones of the rat contain an adenylyl cyclase-stimulating activity antigenically related to parathyroid hormone-related peptide. To ascertain its origin, Northern blotting and in situ hybridization histochemistry were performed. Results demonstrate that mRNA of parathyroid hormone-related peptide is present in RNA extracted from fetal long bones of the rat and that cells responsible for its production are localized in the periosteum. These cells are not mature osteoblasts because they do not synthesize mRNA of osteocalcin. Thus the present study shows that parathyroid hormone-related peptide could be produced locally, at least in part, in the skeleton of fetal rats.

CORRECTION OF LOW CIRCULATING LEVELS OF 1,25-DIHYDROXYVITAMIN D BY 25-HYDROXYVITAMIN D DURING REVERSAL OF HYPOMAGNESAEMIA

The effect of 25‐hydroxyvitamin D (250HD), given orally during the reversal of hypomagnesaemia, was studied in five patients with hypomagnesaemic hypocalcaemia and low serum levels of 25OHD and 1,25‐dihydroxyvitamin D (1,25(OH)2D). The results were compared to those obtained in five other patients with similar initial levels of magnesium, calcium, 25OHD and 1,25(OH)2D who did not receive 25OHD. Serum levels of 1,25(OH)2D in the ten hypomagnesaemic patients were lower than in ten control subjects with low serum levels of 25OHD. The reversal of hypomagnesaemia was similar in the two groups of patients and elicited a similar increase of circulating iPTH levels. The expected increase of circulating 25OHD was observed in patients supplemented with 25OHD; their circulating 1,25(OH)2D rose within 48 h to normal levels, contrasting with the delayed and poor increase of 1,25(OH)2D in patients receiving no 25OHD. The evolution of serum calcium was however identical in the two groups. Our results suggest that vitamin D deficiency was a significant factor leading to low circulating levels of 1,25(OH)2D in hypomagnesaemic hypocalcaemic patients. The biological consequences of low serum 1,25(OH)2D in these patients remain unclear, but clearly, normal levels of 1,25(OH)2D are not essential for the correction of hypomagnesaemic hypocalcaemia.

Parathyroid Hormone and Calcium Blood Levels in Acute Renal Failure

Parathyroid hormone (PTH), creatinine, calcium and phosphate blood levels were repeatedly measured in 5 patients with acute renal failure. 1 patient developed hypercalcemia during the recovery phase o

Effects of lithium on bone resorption in cultured foetal rat long-bones

Abstract. Increased serum calcium has been observed in manic depressive patients treated with lithium (Li), and one of the mechanisms increasing serum calcium could be a sensitizing effect of Li on bone resorption. In a previous study, however, Li has been found slightly to inhibit PTH‐stimulated resorption in cultured foetal rat long‐bones. In this work, we extended the study of the effects of Li on bone resorption in culture when resorption of foetal rat long‐bones was stimulated by factors other than PTH. Li 3 mM had no effect on basal resorption, a slight and inconsistent inhibitory effect on PTH stimulated bone resorption, a moderate and inconstant inhibitory effect on prostaglandin E2 (PGE2) stimulated resorption, and did not significantly affect the enhancement of resorption by interleukin 1 (ILI). The more constant effect of Li was a nearly complete inhibition of the resorption response to 1,25‐dihydroxycholecalciferol (1,25(OH)2D3). This study confirms that Li has no stimulatory effect on bone resorption by itself, nor a sensitizing action on the stimulation of resorption by several activators. Conversely, Li has a striking inhibitory effect on bone resorption stimulated by 1,25(OH)2D3.

La Selle Turcique Vide

SummaryThe empty sella is due to a cyst-like extension of the subarachnoid space into the sella through a congenital incompletness of the sellar diaphragm. Pneumoencephalogram combined with tomography has shown that in our patient the enlarged sella was not occupied by a tumor but by the intrasellar cisterna. Despite the relative paucity of pituitary endocrine abnormalities, pituitary function should be thoroughly evaluated to exclude early endocrine deficiency.

Stimulation of calcitonin secretion by an oral calcium load test in normal subjects and in idiopathic renal stone formers

Circulating concentrations of calcitonin (CT) have been found high in idiopathic renal calcium stone formers (RSF). It has been postulated that this could result from increased serum calcium concentrations following calcium-containing meals. To verify this hypothesis, 15 male idiopathic RSF and 15 male normal subjects underwent plasma CT measurements, following an extraction-concentration technique (exCT), in basal state and during an oral calcium load test. Most RSF exhibited increased excretion of calcium following oral calcium loading, suggesting overabsorption of calcium, but serum calcium did not increase more in RSF than in normal subjects. Basal plasma exCT concentrations were normal in RSF. ExCT plasma concentrations following calcium loading, and the area under the curve of exCT levels, tended to be higher in RSF than in normal subjects, but not significantly. Our results thus do not support the hypothesis that increased plasma CT levels in RSF result from increased serum calcium concentrations following calcium-containing meals.

Evolution of parathyroid hormone and calcitonin plasma levels during haemodialysis and following renal transplantation.

SummaryCreatinine, calcium (Ca), phosphate, immuno-reactive parathyroid hormone (i PTH) and calcitonin (i CT) blood levels were measured before and after haemodialysis (HD) in 24 patients submitted to regular dialysis treatment, and in the days following successful renal transplantation (RT) in other patientsi PTH and i CT levels were elevated before HD; the rise of plasma Ca following HD was accompanied by a decrease in i PTH (P < 0.001), whereas i CT was increased, though not significantly.The levels of i PTH and i CT, elevated before RT, returned to normal after RT, together with creatinine and P levels; a rejection after some days in 2 patients was followed by a rapid increase in i PTH and i CT levels. One patient who underwent subtotal parathyroidectomy 281 days after RT because of persistent hypercalcaemia and high i FTH levels is also presented.

Hypercalcaemia after surgical treatment of Cushing's disease.

with my medical occupations to be able to cultivate their company. I should certainly be unable to satisfy Minervas curiosity about their physical ills. I never met Bertie Russell or Carrington; Lytton Strachey I knew only slightly, though he was kind to me. My closest involvement was with Virginia Stephen. I was living from October 1913 to July 1914 in a room at the top of the Stephens house in Brunswick Square and came back one night to be told that Virginia had just been found unconscious in her room apparently suffering from a deliberate overdose of drugs. The story is well known from Leonard Woolfs autobiography-the headlong rush back to Barts to get a stomach tube and funnel and the time spent that night washing out her stomach with Sir Henry Head kneeling by my side. We were in time and she recovered. This took place before she had written any of her novels and I am pleased to think that I had a hand in making possible the production of this brilliant literary achievement. GEOFFREY KEYNES