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Biomedical subjects

M Audran

Publications and source records attributed to M Audran.

At least 145 records · Page 8Linked to original sources
PubMed1988

Brain penetration of orally administered sodium pyroglutamate.

The absorption and brain penetration of [3H]pyroglutamate was determined after oral administration to rats. Gas-liquid chromatography of the methylated derivatives followed by mass fragmentometry was used to analyse the plasma and brain levels of pyroglutamate. [3H]Pyroglutamate was separated from other labelled compounds by thin layer chromatography. The administration of 500 mg kg-1 [3H]pyroglutamate resulted in a 30-fold increase in plasma levels and a doubling in the brain levels. Over 60% of the cerebral radioactivity was present as [3H]pyroglutamate demonstrating that pyroglutamate is not only well absorbed but also penetrates in significant amounts into the brain.

Animals↗
PubMed1988

[Primary hyperparathyroidism. Recent physiopathological data].

Recent advances in the physiology of the parathyroid hormone permit a better demonstration of the mechanisms of inappropriate hypersecretion which characterizes hyperparathyroidism, even through the etiology of primary forms still remains unknown. There have been also some progress achieved understanding and evaluating the impact od hypersecretion on target organs, especially bone and kidney. Some studies give an indication of the therapeutic modalities which would enable to reduce the excess of secretion, to counteract the effect of the hormone on its receptor sites or finally limit its consequences on osteopenia.

Animals↗
PubMed1988

Comparison of the metabolism and pharmacokinetics of metbufen and itanoxone and their analogues in rats.

Metbufen, II, itanoxone, I, and two other derivatives of gamma-aryl-gamma-keto-substituted butyric acids labelled with 14C in their carbonyl group were synthesized for a metabolic investigation in rats. Profound changes in pharmacokinetic parameters, most specifically in the distribution, elimination, and metabolic pathways, were induced by substitution in the aromatic nucleus or changes in saturation of the aliphatic chain. The metabolites isolated from plasma and urine were identified by gas chromatography and mass spectrometry, by comparison with chemical controls, revealing the processes of metabolism of these structural analogues. This difference in metabolism further understanding of the diversity of biological effects inherent in these compounds.

Administration, Oral↗
PubMed1987

Sarcomatous degeneration in Paget's bone disease.

The authors report 12 cases (8 men and 4 women) of sarcomatous degeneration in Paget's bone disease, with an average age of 72.3 years. Sarcomatous degeneration occurred often in polyostotic Paget's disease, and osteitis deformans was seen in 4 cases. Femur and pelvis were the most affected bones. Pain was a constant feature, whereas tumefaction and fracture were less common. Osteolytic lesions were more frequent than condensed or mixed lesions and radiological signs of malignancy were usually found. Seven cases were histologically classified as osteogenic sarcoma and 3 cases as fibrosarcoma. Electron microscopy was performed on 2 osteogenic sarcomas and in 1 case revealed microcylindrical inclusions in Pagetic osteoclasts and in multinucleated giant tumor cells, but none in mononucleated tumor cells. The average survival time for the patients in this study was only 4.5 months.

Aged↗
PubMed1987

Transient hypoparathyroidism induced by synthetic human parathyroid hormone-(1-34) treatment.

Daily injections of low doses of a synthetic fragment of human PTH [hPTH-(1-34) have increased iliac trabecular bone volume when used in the treatment of osteoporosis. In approximately 50 patients no major side-effects had occurred. However, during daily sc 100-micrograms injections of the peptide, one patient repeatedly developed parathyroid hypofunction which resolved each time treatment was stopped. Specific immunoglobulin G (IgG) antibodies binding [125I]hPTH-(1-34) were identified in the patient's serum, and positive immunohistochemical reactions were obtained when bovine parathyroid sections were exposed to the patient's IgG. After adsorption with PTH, the patient's IgG, free of anti-PTH antibodies, reacted with renal cell membranes, as demonstrated by indirect immunofluorescence and blocked renal PTH-dependent adenylate-cyclase activation in vitro. These results support the hypothesis that anti-PTH receptor as well as anti-PTH antibodies were generated during hPTH-(1-34) treatment, which led to the development of hypoparathyroidism when their titers were high.

Adenylyl Cyclases↗
PubMed1987

[Serum concentrations of 1,25-dihydroxyvitamin D in cases of osteomalacia, parathyroid dysfunction and idiopathic hypercalciuria].

1,25 dihydroxyvitamin D (1,25(OH)2 D) is the active metabolite of vitamin D and has an essential role in bony metabolism on the regulation of the calcium-phosphorus balance. The circulating level of 1,2(OH)2 D is normally between 25 and 45 pg/ml. Isolation of the fraction to be titrated requires sophisticated purification techniques using high performance chromatography (HPLC). In osteomalacia secondary to a deficiency the mean level of 1,25(OH)2 D is low (14.1 +/- 6.9 pg/ml) because of substratum deficiency. Administration of vitamin D supplements is quickly followed by a supraphysiological increase of the level of active metabolite. The role of the parathyroid hormone on the activity of 1-hydroxylase is illustrated by the results of the titration in parathyroid dysfunctions: decrease of the mean level in hypoparathyroidism (18 +/- 6.9 pg/ml), and on the contrary, a significant increase in hyperparathyroidism (56.6 +/- 15.4 pg/ml) despite of a spread of the individual values. In 18 cases of idiopathic hypercalciuria, we have only observed an increase of 1,25(OH)2 D level, in two cases. Titration of 1,25(OH)2 D complements the calcium-phosphorus evaluation to precise the physiopathogenic mechanism of the disorders observed in various diseases. Its interpretation requires the joint measurement of the substratum level, 25-hydroxyvitamin D, and the evaluation of the parathyroid function.

Adult↗
PubMed1987

[Ankylosing panarthritis].

The authors report 4 cases of "Sheathing Panarthritis" (S.P.): two female patients with a positive rheumatoid serology, presented a complete ankylosis of the articular system, including the temporo-mandibular joint and the spine; two male patients presented a complete articular ankylosis of the lower extremities and a more or less total spine ankylosis, by only a slight involvement of the upper extremities. The study of the HLA system, carried out in ten cases--3 in this series--showed the presence of B27 in six cases, and the presence of A2 in five cases out of eight. A single study of locus DR revealed the presence of DR 1. On the nosological point of view, this radio-clinical picture, individualized by Forestier, was successively considered as an autonomous affection, a rheumatoid polyarthritis (P.R.), an ankylosing spondylarthritis (AS). The author's opinion is dual since, from the analysis of the cases, they do not feel that it is possible to classify all cases either with P.R. or with A.S. After studying the various radio-clinical aspects of P.R., they believe that, in patients with S.P., it exists an ankylosing "factor X" which exacerbates the ability of P.R. and A.S. to manufacture sclerosis, transforming these diseases into S.P.

Adult↗
PubMed1986

The physiology of the vitamin D endocrine system.

It is clear that the vitamin D endocrine system plays a central role in the maintenance of calcium and phosphate homeostasis. It may be involved in the cellular differentiation and growth of various cells. Investigation of these properties in the future is likely to yield interesting information concerning the biology of this sterol hormone.

Animals↗
PubMed1985

Physicochemical and structural study of sulfamethazine.

We have shown by several physicochemical methods that the existence of different crystal habits for a given molecule does not necessarily imply polymorphism. For sulfamethazine, we found one polymorph, form 1, whose crystalline structure is published herein, and a methanol solvate.

Calorimetry, Differential Scanning↗
PubMed1985

The physiology and pathophysiology of vitamin D.

The vitamin D endocrine system plays an important role in the maintenance of normal calcium homeostasis. Abnormalities of this system occur in many conditions, such as rickets, osteomalacia, hypoparathyroidism, and hyperparathyroidism. The diagnosis and treatment of these disorders will be facilitated if the clinician understands the general mechanisms by which defects in vitamin D metabolism and action occur. We review this information and discuss the use and limitations of vitamin D metabolite assays for diagnosis of clinical disorders of mineral metabolism.

Calcifediol↗