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Biomedical subjects

C Proye

Publications and source records attributed to C Proye.

At least 217 records · Page 12Linked to original sources
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↗
PubMedDate not supplied

[Usefulness and limits of intraoperative hormone measurements in surgery of endocrine duodeno-pancreatic tumors: experience of 72 cases].

Intraoperative hormonal measurement has been successfully used to guide the surgical treatment of various endocrine diseases. In this study, we report the results of intraoperative insulin measurement in patients with organic hypoglycemia (n = 52 operations in 51 patients) and the results of intraoperative gastrin measurement in patients with gastrinoma (n = 20). Measurements were done in the systemic and portal blood at the beginning of the operation, and 20 min after removal of the lesion(s), with intra-operative secretin stimulation test for gastrinoma in some cases. Results accurately predicted cure (insulinomas) or non-cure (half of gastrinomas) of the disease. Limitations of the method are the possibility of normal hormone base line levels at the time of surgery and the importance of secretion of pro-insulin products by insulinomas not taken in account by the assay with monoclonal antibodies.

Biomarkers, Tumor↗
PubMedDate not supplied

Human pancreatic ductal cells: large-scale isolation and expansion.

The in vitro differentiation of pancreatic stem cells has recently been shown to represent a new source of beta cells for cell therapy in diabetes. Human ductal cell differentiation, in vitro, has been documented in three-dimensional (3D) culture and recently substantiated. Although encouraging, the optimization of the ductal cell source, expansion and differentiation ex vivo are mandatory for clinical relevance. We compared three sources of human ductal cells (hDC) (method A1-2, B, and C). The classical main duct isolation of hDC by explant (A1), or enzymatic digestion (A2), was compared with two indirect methods: from 3D cultured human islet/duct-enriched fractions (B) and dedifferentiated exocrine fractions (C). Method A: few viable hDC were obtained from the main duct. Method B: embedding islet/duct rich fraction in 3D collagen gels expands the cytokeratin 19 (CK19)-positive ductal component in the form of ductal cysts, as we described previously; monolayers derived from digested cysts were 80% ductal (CK19). Method C: initially adherent amylase-positive exocrine clusters contained 12% (CK19) to 22% (CK7) ductal cells. One-week exocrine cultures were amylase negative and 46% (CK19) to 63% (CK7) ductal. Cell viability varied: <20% (A1), 81+/-12% (B), 91+/-2% (C). Extrapolating total yields we obtained (+/-SEM): 10.5+/-4.6 x 10(3) (A1), 36+/-18 x 10(3) (A2), 292+/-50 x 10(6) (B), 1696+/-526 x 10(6) (C) viable hDC per pancreas. A secondary monolayer expansion of cyst-derived hDC (method B) was achieved with NuSerum (4.2-fold on plastic, 2.6-fold on 804G matrix; p < 0.05 vs. control cells on plastic). First passage exocrine-derived ductal cells also responded to matrix and to growth factors, albeit not significantly. In conclusion, this study demonstrated that an abundant hDC supply can be obtained from islet/duct or exocrine fractions followed by monolayer expansion with NuSerum. If their differentiation capacity is confirmed, in particular exocrine-derived ductal cells may represent a promising abundant source of islets for allogenic and autologous diabetes cell therapy.

Cell Differentiation↗
PubMedDate not supplied

[Surgery of insulinoma].

Pre-operative imaging of insulinomas should always be considered, but, if diagnosis is certain, negative imaging studies should never preclude laparotomy. A pre-operative medical trial with Diazoxide is mandatory to check its efficiency and thus allow better therapy at the end of a fruitless exploration, avoiding unnecessary blind pancreatic resection. And even sometimes, its efficiency may lead to discard surgery in a frail elderly patient or in the special patient with multiple tumors and the MEN I syndrome. State-of-the-art surgical exploration requires careful intra-operative monitoring of blood glucose--possibly with biostator--allowing control of completeness of the procedure. Intra-operative localization of the inciting tumor requires full pancreatic mobilization, careful palpation, intra-operative echography and sometimes insulin staged portal sampling with quick intra-operative assay. Insulinomas are very rarely ectopic, but they are multiple in 10% of cases, three out of four such cases in a MEN I setting. Any type of pancreatic resection can be used for tumour removal, but the more conservative one, i.e, enucleation should be elicited, especially in the head. Ultrasonic dissection is a useful tool. Left pancreatic resection should aim to spare the spleen. Completeness of tumor removal is assessed by the hyperglycemic rebound--sometimes delayed till 40 minutes--, a dramatic plasma insulin decrease and possibly change in biostator output. Blind pancreatic resection should be given up. Surgery of liver metastases is of anecdotal interest. Chemotherapy and SMS-analogs can provide long-term palliation.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic Imaging↗