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Biomedical subjects

R Villet

Publications and source records attributed to R Villet.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Subclinical identification of cancer of the breast. Radiologic progress, proposition for treatment].

In the case of breast cancer with no clinical signs, radiological signs are the decisive factors to indicate surgery, histological studies or treatment. Foci of microcalcifications currently are the feature to identify as a rule. However, they reveal canalicular carcinoma in only 1 case out of 3. We propose a radiological technique allowing the selection of the microcalcifications to be operated by means of the digitization of a mammographic film and of a software-controlled morphometric analysis. 10,000 microcalcifications have been studied in this way. The most reliable of the 12 parameters that were distinguished is compacity. 100 files were studied with conventional mammography and a morphometric and histological analysis. Any microcalcification less compact than 0.35 is highly suspicious, since this parameter is the only one having a significant difference, with a confidence interval of 95%. The patients are now selected in this way. Differences in the age of the lesions, multiple foci and sometimes lesions with multiple centers lead us to automatically propose the exeresis of the gland, followed by immediate reconstruction of its shape and volume. According to a retrospective study we carried out on 111 subclinical intracanalicular carcinomas after a 5 to 20-year time interval, recurrence is observe in only 4.5% of all cases.

Breast Neoplasms↗
PubMed1989

[Diagnosis and treatment of epithelial cancer of the ovary. Apropos of 102 cases].

This is a retrospective study including 102 cases records of female patients presenting with epithelial carcinoma of the ovary. Survival, as in the other series, depended upon the stage of the cancer at the time of diagnosis, mean survival rates being 77.1, 57.7, 26.6 and 19.3 for stages I, II, III and IV respectively. However, most of all, survival was related to the quantity of remanent tumoral tissue following the initial laparotomy. The 5-year survival rates were 84%, 42% and 10% when there was no residual tumor, when the latter measured less than 2 cm, and more than 2 cm, respectively. In contradistinction to what is generally found in such studies, the diagnosis here was established at earlier stages, since 53% of the cases of interest were female patients with stage I or II carcinoma. The chief argument, therefore, is based on the methods of early diagnosis and, judging from what is generally admitted in literature, on the place of extended surgery.

Adult↗
PubMed1988

Generation of high specificity of effect through low-specificity binding of proteins to DNA.

It is proposed that proteins can bind with relatively low-affinity and specificity to multiple sites, defined as sequence motifs, on polynucleotide chains, and that such binding can collectively be turned into high-affinity, high-specificity binding through cooperative effects, especially when the sequence motifs recur periodically. The selection of individual nucleotides has in general been thought to be the condition of the existence and conservation of function in most of the noncoding sequences. This condition seems unnecessary. Calculations are presented as a step in the direction of giving credibility to a model of stable gene repression.

DNA↗
PubMed1988

Concentration-affinity equivalence in gene regulation: convergence of genetic and environmental effects.

It is proposed that equivalent phenotypic effects can be obtained by either structural changes in macromolecules involved in gene regulation or changes in activity of the structurally unaltered macromolecules. This equivalence between changes in activity (concentration) and changes in structure can come into play within physiologically plausible limits and seems to represent an important interface between environment and genome--namely, between environmentally determined and genetically determined gene expression. The equivalence principle helps explain the appearance of phenocopies. It also points to a general pathway favorable to the occurrence, during evolution, of frequent episodes corresponding to Waddington's genetic assimilation and is likely to represent one component of the system responsible for the high frequency of recurrence of parallel evolution.

Biological Evolution↗
PubMed1985

Vascular evolution of single-layer end-on colonic anastomosis. A microangiographic study of 180 anastomoses in the rat from two to 180 days.

One hundred eighty left colonic single-layer end-on anastomoses performed on 90 rats by microsurgical techniques, using polydioxanone monofilament absorbable sutures, were examined histopathologically and microangiographically at nine different times, from two to 180 days. There was no anastomotic leakage. The vascular state after suturing and the evolution of the neovascularization are described. The neovascularization appeared to follow the same process of evolution as tissue restoration. It began early, was greatest on the seventh day, and diminished thereafter. When granulation tissue was narrow, the anastomoses were barely hypervascular, the neovascularization assured by submucosal plexus. A voluminous granulation tissue was hypervascular, had a slower evolution, and neovascularization was then assured above all by the peritoneal formations adherent to the suture.

Animals↗
PubMed1985

Hyperenteroglucagonaemia and small intestinal mucosal growth after colonic perfusion of glucose in rats.

Beside intraluminal factors, humoral agents play an important role in intestinal adaptation. Enteroglucagon, the mucosal concentration of which is maximal in the terminal ileum and colon, is the strongest candidate for the role of small intestinal mucosal growth factor. The present experiment was designed to study the role of colonic enteroglucagon in stimulating mucosal growth in rats with a normal small intestine. After eight days of glucose large bowel perfusion, enteroglucagon plasma concentrations were 120.7 +/- SEM 9.2 pmol/l, versus 60.1 +/- 6.8 in mannitol perfused control rats (p less than 0.001). Gastrin, cholecystokinin, neurotensin, pancreatic glucagon, and insulin plasma concentrations were unchanged. Crypt cell proliferation, measured by the vincristine metaphase arrest technique, increased significantly in the small intestine of glucose perfused animals (p less than 0.005-0.001) in comparison with the controls. This resulted in a greater mucosal mass in both proximal and distal small bowel: mucosal wet weight, DNA, protein and alpha D-glucosidase per unit length intestine were all significantly higher (p less than 0.05-0.001) than in mannitol perfused rats. Our data, therefore, support the hypothesis that enteroglucagon is an enterotrophic factor and stress the possible role of the colon in the regulation of small bowel trophicity.

Animals↗
PubMed1985

[Hemorrhagic rectocolitis associated with idiopathic thrombopenic purpura].

This case report documents severe autoimmune thrombocytopenia in a 20 yrs. old patient with ulcerative colitis. Diagnosis of idiopathic thrombocytopenic purpura was made on the presence of bound antiplatelet antibodies and on the absence of any other disorder capable of provoking a platelet fall. Colonic lesions were moderate but were resistant to steroids and total parenteral nutrition. Thrombocytopenia resisted to steroids and vincristine and a major fall in the platelet count (less than 10,000/mm3) occurred in two instances. However, platelets rose transiently after high-dose intravenous gamma-globulins. The patient underwent splenectomy, colectomy and ileostomy because of life-threatening colonic hemorrhage. The platelet count rose to normal levels within one week after surgery. Ileorectal anastomosis was subsequently performed. One year later the patient was in good health and his platelet count had returned to normal.

Adult↗
PubMed1983

Selective increased tissue histamine levels in tumour-bearing rodents.

Histamine levels increased in the fundus of mice bearing a primary 3-methylcholanthrene-induced fibrosarcoma, and in the ventral skin, skeletal muscle and rumen of rats bearing a D.M.B.A. induced mammary adenocarcinoma; they did not increase in the tissues of mice bearing a McC3-1 fibrosarcoma (38th passage) or a Lewis lung carcinoma before the appearance of metastasis, but an increase in histamine levels was observed in dorsal skin, ventral skin and fundus, after the appearance of metastasis.

Animals↗
PubMed1979

[Thyroid carcinoma. Indications and results of treatment (author's transl)].

Frozen section histological study of all cold nodules requiring total extracapsular lobectomy is absolutely essential during surgery. Whilst total thyroidectomy for intracapsular carcinomas is most often proposed in extracapsular carcinomas, the authors deliberately leave a small part of the gland in contact with the parathyroids. The need for recurrent laryngeal lymph node dissection is accepted, as is the principle of jugulo-carotid dissection.

Adult↗