[Hypervitaminosis A: physiopathology and liver toxicity].
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Biomedical subjects
Publications and source records attributed to J Rahier.
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Insulin, glucagon, somatostatin and pancreatic polypeptide cells were stained by immunoperoxidase techniques and quantitated morphometrically in sections of pancreases obtained from eight control subjects, four Type 1 (insulin-dependent) and eight Type 2 (non-insulin-dependent) diabetic patients. The whole pancreas was studied to take into consideration the heterogeneous distribution of the different cell types. From the volume density of each cell type, and the weight of each lobe of the pancreas, the total mass of endocrine tissue was calculated. It averaged 1395 mg in control subjects, 413 mg in Type 1 and 1449 mg in Type 2 diabetic patients. The loss of endocrine tissue observed in the Type 1 patients was almost restricted to the lobe poor in pancreatic polypeptide cells. In these patients, B cells were practically absent (at the most seven per section), but the 'atrophic islets' still contained numerous A, D, or pancreatic polypeptide cells. The mass of A, D and pancreatic polypeptide cells and the ratio of D to A cells were not different from those measured in the control subjects. This shows that the disappearance of B cells in Type 1 diabetes has no preferential effect on any other endocrine cell of the pancreas. In Type 2 diabetes, the mass of A cells was increased, whereas that of B, D and pancreatic polypeptide cells was not changed. This hyperplasia of A cells leads to a decrease in the ratio of B to A and of D to A cells. These alterations may enlighten certain aspects of the physiopathology of Type 2 diabetes.
Pancreases from insulin-dependent diabetics (IDDM), noninsulin-dependent diabetics (NIDDM), and nondiabetic subjects were analyzed by stereological and morphometrical methods in order to determine the weight of the lobe rich in pancreatic polypeptide (PP) cells in relation to the total weight of the pancreas and the volume density of PP cells in both parts of the gland, those rich and poor in PP cells. In control subjects, neither the relative weight of the lobe rich in PP cells, nor the volume density of PP cells varied significantly with aging. In IDDM and NIDDM, the volume density of PP cells was similar to that observed in control subjects. The total weight of the pancreas was markedly decreased in IDD because of an almost selective atrophy of the lobe poor in PP cells; the relative weight of the lobe rich in PP cells was thus much higher than that in control subjects. A less marked atrophy, restricted to the lobe poor in PP cells, was also observed in NIDDM. It is suggested that PP may exert a local trophic role which protects the lobe of the pancreas rich in PP cells from atrophy in diabetic patients. The results further show that the elevated levels of PP in the plasma of elderly or diabetic subjects cannot be ascribed to a hyperplasia of PP cells.
A 47 year-old male epileptic who had been treated for eight years with variable doses of phenobarbital and valproate was hospitalized in the intensive care unit with the following clinical and biological features: coma grade 2, metabolic acidosis, acute renal and hepatic failure. The recent clinical history revealed that he had been using CCl4 to clean paintings for the last three days in a confined atmosphere. Upon admission, the recent absorption of CCl4 was confirmed by the detection of the solvent in blood and adipose tissue. Cellular lipoperoxidation was suggested by the presence of an increased concentration of pentane in expired air. Evidence of microsomal enzyme induction was provided by the relative preservation of aminopyrine demethylation as indicated by the 14C-aminopyrine breath test and also by the morphological evidence of endoplasmic reticulum proliferation at liver biopsy. Supportive therapy, repeated haemodialysis and administration of antioxidant drugs resulted in a complete recovery. The unusual severity of CCl4-induced liver and renal injury observed in this case is best explained by the induction of CCl4 microsomal activation due to phenobarbital therapy.
Corpora lutea from 12 pregnant women were prepared for immunohistochemical localization of relaxin using a highly specific antiserum. A positive response is given by luteal cells that are diffusely distributed throughout the corpus luteum. These cells do not form a distinctive group in any particular area. A negative response is seen in the adjacent ovarian tissue, and also in nongestational corpora lutea in early luteal phase.
Pancreases from normoglycaemic neonates (less than 15 days), infants (6 months) and adults were examined using immunoperoxidase techniques. Sections taken from five regions of the gland were analysed by morphometry. The volume density of total endocrine tissue was found to be higher than previously reported: 15% in neonates, 6-7% in infants and 2-3% in adults. In neonates, many endocrine cells were located in small clusters, sometimes budding from ducts, and up to 15% were isolated in ducts and acini. Similar clusters were still present, though less frequent, in infants. The relative proportion of all cell types varied only slightly between the different regions, except in the posterior part of the head, which comprised 90% of all PP(polypeptide) cells. With age, the proportion of somatostatin cells decreased (from about 30% in neonates to about 10% in adults), that of insulin cells increased (50 to 70%) and that of glucagon cells remained stable (20%). In the posterior part of the head, the proportion of PP cells tended to be higher in adults than in neonates or infants. This study shows that both the endocrine cell populations and the proportion of endocrine tissue in the pancreas change markedly in early life. It also suggests that "nesidioblastosis" is a normal feature of the pancreas of normoglycaemic neonates and young infants.
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Pancreatic polypeptide (PP) cells were studied in human endocrine pancreatic tumours and in normal human pancreata by immunohistochemical techniques and electron miscroscopy. The existence of long cytoplasmic processes was demonstrated both in tumours and normal tissue. These processes are in close contact with other endocrine cells or with acinar cells. This particular morphological aspect suggests that PP cells may control the function of other cells via paracrine secretion.
Pancreatic somatostatin cells have been studied in human neonates and adults using an immunoperoxidase technique. Their volume density in the head, isthmus, corpus and tail of the gland has been estimated by morphometry. Somatostatin cells were about 20 times more frequent in the neonate (5% of all pancreatic cells) than in the adult (0.23%). Their distribution between the different zones of the pancreas showed few differences except for the lobe of the head rich in PP cells, where the volume density of somatostatin cells was 40% lower.
The localization of pancreatic polypeptide (PP) cells was studied in the pancreas of four human neonates by specific immunocytochemical techniques. PP cells were detected in all parts of the pancreas. However, examination at low magnification showed that they were considerably more numerous in a small lobe, located at the posterior-inferior part of the head region. It is suggested that this lobe corresponds to the part of the pancreas that is derived from the ventral primordium. Both in the lobe rich in PP cells and in the remainder of the pancreas, approximately 75% of PP cells were present in the islets and 25% distributed among acini and ducts.
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The authors report the case of two patients with secondary hemochromatosis in whom a C282Y mutation in the heterozygotic form was observed. They discuss the potential relationship between secondary hemochromatosis and the presence of the genetic abnormality.
We report on a patient who presented, on 2 occasions at one-year interval after a treatment with the amoxicillin-clavulanic acid association, a clinical and biological picture in keeping with the diagnosis of immuno-allergic hepatocellular hepatitis. On liver biopsies, the most characteristic finding was portal and lobular eosinophilic infiltration without cholestasis and biliary ducts damage.
The aim of this study was to report the clinical characteristics of 13 patients with Hürthle carcinoma. In the vast majority of them, disease was suspected by a palpable thyroid nodule. The results of preoperative examination (scintigraphy, ultrasonography, thyroglobulin) are also discussed as well as the pathological aspects and follow-up characteristics after total thyroidectomy.
A case of a thirty-nine year old woman with cerebral cavernous angiomas who developed anaemia and thrombocytopenia secondary to diffuse liver angiosarcoma is reported. This unique association of liver angiosarcoma and cerebral cavernous angiomas may suggest that this tumour may potentially develop from benign vascular lesions. Hematologic abnormalities in angiosarcomas are moreover reviewed based on recent literature search.
We report the case of a 24-year-old euthyroid woman in whom the discovery of a cold nodule in the left thyroid lobe led to a thyroidectomy. The surgical specimen was characterized by a diffuse black discoloration. Optical examination revealed brown granules within the apical portion of the follicular cells whereas ultrastructural studies showed intralysosomal lipofuscin-like deposits, all findings consistent with pathological descriptions reported in black thyroids associated with the intake of minocycline. Retrospectively, we were told that the patient had received this antibiotic for at least three years for the treatment of acne vulgaris. As experimental models have demonstrated potential antithyroid effects of the drug, it appears relevant to monitor thyroid tests in patients receiving long-term minocycline therapy.