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Biomedical subjects

I Grimbert

Publications and source records attributed to I Grimbert.

8 recordsLinked to original sources
PubMed1986

[Histomorphometric data in 5 cases of pseudohypoparathyroidism: discussion on bone sensitivity to parathyroid hormone].

We studied 5 patients (aged 8 to 18) presenting chronic calcipenia with hyperphosphatemia and an increase in C terminal-specific immunoreactive parathyroid hormone. Systematic radiography of the hands revealed 2 cases with signs of subperiosteal resorption characteristic of hyperparathyroidism and 2 cases of cortical fibrillation. These cases were monitored by measuring phosphate levels in the urine after injection of parathyroid hormone (Ellsworth-Howard test), by determining urinary elimination of cyclic AMP after injection of parathyroid hormone (Chase-Aurbach test) and by assaying cyclic AMP levels in the plasma after intravenous administration of parathyroid hormone (Tomlinson-Hendy test). These 3 measurements revealed no changes upon injection of parathyroid hormone, even after administration of vitamin D, thus suggesting renal resistance to parathyroid hormone. The absence of cyclic AMP secretion is suggestive of perturbation of the membrane receptor. Histomorphometric study of the bones showed an increase in resorption and osteoid areas and in the relative osteoid volume without modification of osteoid thickness, which is very suggestive of an effect of parathyroid hormone on the bone. Pseudohypoparathyroidism was, then, characterized by renal resistance to parathyroid hormone and an effect of the latter on bone cells.

Adolescent↗
PubMed1986

[Sensitivity of bone to parathyroid hormone in type I pseudohypoparathyroidism. 6 cases].

The sensitivity of bone to parathormone in pseudoparathyroidism is not well known. Six patients with Type I pseudohypoparathyroidism (4 with Albright's osteodystrophy) had increased alkaline phosphatase levels (5 patients) and radiological signs of periosteal resorption in the hand in one case. All patients had histological signs of increased surfaces of resorption and periosteocytic lacunae, increased osteoid surfaces and relative osteoid volume with no change of the index of osteoid thickness. These changes are identical to those observed in hyperparathyroidism which leads on to the discussion of the role of the increased parathormone secretion induced by the lack of calcium on the remodeling of bone. Our six cases show that there is no bone resistance to parathormone. The diversity of bone changes in hyperparathyroidism, similar to that of primary hyperparathyroidism, is without doubt dependent on the degree of renal insensitivity to PTH through the inactivation of vitamin D.

Adolescent↗
PubMedDate not supplied

[Alpha-methyl-paratyrosine in the treatment of malignant pheochromocytoma].

Alpha-methyl-paratyrosine (Demser) is a specific inhibitor of tyrosine hydroxylation to dopa. It is administered orally and may be given in combination with symptomatic treatments to reduce the hypersecretion of catecholamines. We report two cases of malignant phaeochromocytoma in which this drug was used. A pharmacological study of the compound is presented, and the literature on its long-term use in the treatment of malignant phaeochromocytoma is reviewed. In our second patient, who received alpha-methyl-paratyrosine for 9 months, a study of changes in differential catecholamine excretion showed that the urinary catecholamines were redistributed, with an increase in the dopamine/norepinephrine ratio. An HPLC study of urinary excretion of catecholamines demonstrated that their levels cannot be significantly increased by excretion of alpha-methyl-paratyrosine or its metabolites.

Adrenal Gland Neoplasms↗