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Biomedical subjects

A Le Treut

Publications and source records attributed to A Le Treut.

At least 19 recordsLinked to original sources
PubMed1997

Magnetic resonance imaging in the treatment planning of radiation therapy in carcinoma of the cervix treated with the four-field pelvic technique.

PURPOSE: To evaluate magnetic resonance imaging (MRI) in the planning of radiation therapy for patients with carcinoma of the cervix treated with a four-field technique. METHODS AND MATERIALS: Between May 1994 and February 1995, 18 patients with carcinoma of the cervix were entered in the study (1 T1 N-; 2 T2a N-; 1 T2b NO; 10 T2b N-; 2 T2b N+; 2 T3b N+). Node status was assessed by a laparoscopic pelvic lymphadenectomy. During the first step, all the patients were simulated with an isocentric four-field pelvic technique. In one group (11 patients) simulation was done based on clinical examination, computed tomography (CT), and standard guidelines. In the second group (seven patients) simulation was based on clinical examination, CT, and with the help of diagnostic MRI, which was available at that time. During the second step, MRI in treatment position with skin markings of the isocenter of the radiation fields was then performed in every patient. During the third step, in each patient, the simulated radiation fields were correlated with the MRI defined target volume by superimposing them on midsagittal and midcoronal MR images. The adequacy of the margins was arbitrarly defined as 1 cm around the MRI defined target volume (tumor of the cervix and its extension, and uterus). RESULTS: In the first group (11 patients), MRI in treatment position led to a change in 7 patients: six inadequate margins in the lateral fields and one in the anterior and lateral field. In almost all the cases, the adjustments were of an increase of 10 mm, equally matched between the anterior and posterior borders of the lateral fields. In the second group (seven patients), MRI in treatment position has led to a change in lateral fields in five patients. The mean adjustment was 10 mm: four increases (two anterior border, one posterior border, one anterior and posterior border), and one decrease of the posterior border. In the two groups, modifications of the anterior border of the lateral fields have allowed adequate margins around the uterine fundus and modifications of the posterior border have allowed adequate coverage of the cervical tumor. CONCLUSION: When treating carcinoma of the cervix with a four-field radiation technique, standard portals do not exist. The design of lateral fields has to be based on individual morbid anatomy, which is given accurately by diagnostic MRI. Magnetic resonance imaging in treatment position assesses the design of simulated lateral fields.

Adenocarcinoma↗
PubMed1995

Structural analysis of CFTR gene in congenital bilateral absence of vas deferens.

Congenital bilateral absence of the vas deferens (CBAVD) is found in most males with cystic fibrosis (CF), but this malformation can be observed without any pulmonary or digestive features. We have analyzed 13 exons of the CF gene in a cohort of 25 CBAVD patients. Among the 50 chromosomes studied, 24 mutations were identified: delta F508 (14 cases), R117H (7 cases), R1070W (2 cases), 621 + 1 G --> T (1 case), and A1067V (1 case). Except for delta F508, the most frequent mutations (R117H, R1070W) were not observed in the CF group (109 patients) studied in our laboratory. We discuss the significance of these results.

Adult↗
PubMed1995

Proteases.

Proteases are enzymes which are widely distributed in cells and play a key role in protein metabolism. The aim of this paper is to review the classification and nomenclature of proteases, their catalytic mechanisms, the regulation of proteolytic activity and finally the major biological functions of proteases.

Animals↗
PubMed1994

Anonymous marker loci within 400 kb of HLA-A generate haplotypes in linkage disequilibrium with the hemochromatosis gene (HFE)

The hemochromatosis gene (HFE) maps to 6p21.3 and is less than 1 cM from the HLA class I genes; however, the precise physical location of the gene has remained elusive and controversial. The unambiguous identification of a crossover event within hemochromatosis families is very difficult; it is particularly hampered by the variability of the phenotypic expression as well as by the sex- and age-related penetrance of the disease. For these practical considerations, traditional linkage analysis could prove of limited value in further refining the extrapolated physical position of HFE. We therefore embarked upon a linkage-disequilibrium analysis of HFE and normal chromosomes from the Brittany population. In the present report, 66 hemochromatosis families yielding 151 hemochromatosis chromosomes and 182 normal chromosomes were RFLP-typed with a battery of probes, including two newly derived polymorphic markers from the 6.7 and HLA-F loci located 150 and 250 kb telomeric to HLA-A, respectively. The results suggest a strong peak of existing linkage disequilibrium focused within the i82-to-6.7 interval (approximately 250 kb). The zone of linkage disequilibrium is flanked by the i97 locus, positioned 30 kb proximal to i82, and the HLA-F gene, found 250 kb distal to HLA-A, markers of which display no significant association with HFE. These data support the possibility that HFE resides within the 400-kb expanse of DNA between i97 and HLA-F. Alternatively, the very tight association of HLA-A3 and allele 1 of the 6.7 locus, both of which are comprised by the major ancestral or founder HFE haplotype in Brittany, supports the possibility that the disease gene may reside immediately telomeric to the 6.7 locus within the linkage-disequilibrium zone. Additionally, hemochromatosis haplotypes possessing HLA-A11 and the low-frequency HLA-F polymorphism (allele 2) are supportive of a separate founder chromosome containing a second, independently arising mutant allele. Overall, the establishment of a likely "hemochromatosis critical region" centromeric boundary and the identification of a linkage-disequilibrium zone both significantly contribute to a reduction in the amount of DNA required to be searched for novel coding sequences constituting the HFE defect.

Alleles↗
PubMed1992

Anonymous markers located on chromosome 6 in the HLA-A class I region: allelic distribution in genetic haemochromatosis.

Two yeast artificial chromosomes of the HLA class I region were subcloned. Four of the subclones studied displayed restriction polymorphisms that corresponded to six bi-allelic series. Allelic distribution of the anonymous markers was then studied by comparing a control population with a group of patients with familial haemochromatosis. Only one marker presents an unequivocal association with the haemochromatosis gene and is 100 kb centromeric to HLA-A. This association however is not as strong as with HLA-A3. The results suggest two possible locations for the haemochromatosis gene: less than 100 kb centromeric to the HLA-A locus, or on the telomeric side.

Alleles↗
PubMed1992

[Breast microcalcifications].

Microcalcifications of the breast are better recognized as the quality of mammographs is improving. The clinical examination and complementary modalities are often essential to evaluate their significance and point out to an indication for surgery. However, especially when the microcalcifications are detected during a systematic examination, a strict analysis of mammographs is essential. The number of useless punctures must be reduced, as their psychological impact and socioeconomic weight are already demonstrated. Although there is no consensus, most recent publications contain ideas converging on the selection of the indications for a histological control on the basis of an accurate semiological study.

Breast Diseases↗
PubMed1992

[Extramammary carcinoid tumor metastatic to the breast. Apropos of a case].

We report the case of a 42-year-woman treated for an appendicular carcinoid tumor with bilateral ovary metastases and mesenteric node involvement. After a systematic mammography, an infraclinical lesion of the breast was detected. Mammographic and echographic images revealed nodular mass with possibly malignant features. Fine-needle aspiration biopsy indicated malignancy. The definitive diagnosis of breast metastasis of a carcinoid tumor was made by biopsy. This case is related to 14 previously published cases. The authors emphasize the importance of making a precise histological diagnosis to avoid overtreatment of a metastatic lesion.

Adult↗
PubMed1991

Metastases to the breast: differential diagnosis from primary breast carcinoma.

Eight patients with breast metastases from primary tumors other than breast carcinoma were studied: 3 malignant melanomas, 2 rhabdomyosarcomas, 1 malignant mesothelioma, 1 appendiceal carcinoid, and 1 epidermoid cervical carcinoma. All had mammographic, histopathologic, and immunohistochemical examinations. The main problem was differential diagnosis from primary breast carcinoma. History of extramammary primary tumor was helpful but breast metastasis was the first clinical feature in 2 cases. Patients had noticed palpable, round, rapid growth masses which were mammographically benign. Pathologic diagnosis was difficult and immunohistochemical studies necessary, whenever the proliferation had histologic features of primary breast carcinoma or when no primary tumor was known. However, some histologic features were of value for diagnosis of metastasis: atypical histologic features for a primary breast carcinoma, a well-circumscribed tumor with multiple satellite foci, the absence of an intraductal component, and the presence of many lymphatic emboli. In adults, the most frequent types of tumors metastasizing in the breast are malignant melanoma and neuroendocrine-like tumors, especially small cell carcinoma and carcinoid. In children, rhabdomyosarcoma is the most common. Accurate diagnosis of breast metastasis is important to avoid unnecessary mastectomy and to implement an appropriate systemic therapy.

Adolescent↗
PubMed1989

Biochemical aspects of alpha-L-fucosidase in hepatocellular carcinoma.

Biochemical characteristics of alpha-L-fucosidase (alpha-L-fucoside hydrolase, EC 3.2.1.51) were studied in tumorous and nontumorous human hepatocellular carcinoma (n = 14). Five parameters were studied: (i) specific activity, (ii) thermostability, (iii) enzyme affinity for an artificial substrate (Km), (iv) isoenzyme patterns of the glycosidase before and after neuraminidase treatment and (v) pH influence on enzyme activity. The specific activity of alpha-L-fucosidase was significantly decreased in tumoral liver when compared to nontumoral liver. The curve of pH activity constantly showed a broad optimum centered near pH 5, whereas two optima were always observed in nontumoral areas. In contrast, there was no modification of the thermostability, the substrate affinity and the isoenzyme patterns of alpha-L-fucosidase in hepatocellular carcinoma.

Adenoma↗
PubMed1989

Pathophysiological variations in the rat liver plasma membrane serine proteinase activity.

The effects of fasting, diabetes, cholestasis, two-third hepatectomy and adrenalectomy on the rat liver plasma membrane serine proteinase activity were studied. Our results show a significant decrease of the enzyme activity during fasting (-50%), during experimental diabetes (-50%), in regenerating liver after partial hepatectomy (-70%) and after extrahepatic cholestasis (-70%). No modifications are noted when the rats are bilaterally adrenalectomized. These findings suggest that the enzyme activity may be linked to the level of circulating insulin, and may be regulated in physiological cellular proliferation so as to prevent undesirable protein degradation.

Adrenalectomy↗
PubMed1989

[Diagnosis of bilateral secondary tumors of the kidney. Contribution of cytology. Apropos of 2 cases].

The authors report bilateral secondary tumors of the kidney in two patients: one previously treated for an epidermoid tumor, the other for an anaplastic bronchial tumor. In both patients, clinical and radiological features were those of a malignant process. Scan-guided percutaneous fine needle aspiration provided the material necessary to make a definitive cytological diagnosis; it was thus possible to assess the malignancy and recognize the histological type of lesions.

Adult↗
PubMed1989

Effects of perhexiline maleate on asialo-orosomucoid receptor endocytosis and recycling in HTC cells.

Perhexiline is a lysosomotropic agent which has proved to be very valuable to certain patients suffering from angina pectoris. However long-term administration of the drug may induce hepato- and neuro-toxicity. Using HTC cells (a rat hepatoma-derived cell line) whose plasma membranes were labeled with NaB[3H]4 after oxidation by NaIO4, endocytosis and recycling of labeled asialo-orosomucoid (ASOR) receptors were investigated in the presence of 50 mumols/l perhexiline maleate. The results demonstrate that the drug induces a significant decrease of the rate of both the internalization and the recycling of ASOR receptors. The mechanisms responsible for these effects have not yet been elucidated. However, the current findings may be related to the previously observed inhibitory effect of perhexiline on cellular (Na+, K+)-ATPase and Mg++-ATPase activities. Our findings would then reflect insufficient cellular energy production, resulting from depressed ATP hydrolysis in the presence of perhexiline.

Animals↗
PubMed1989

[Adrenal myelolipoma and Castleman's pseudotumor. A case of association in a retroperitoneal tumor].

The authors report a case of a voluminous retroperitoneal tumor as an incidental finding in a patient with acute urine retention induced by an ovarian compressive cyst. Radiological findings supported the hypothesis of a malignant tumor. The histological examination of the surgical specimen only permitted the diagnosis and showed the association of an adrenal myelolipoma with a Castleman's pseudo-tumor.

Adrenal Gland Neoplasms↗
PubMed1988

Adjuvant trial for stage II receptor-positive breast cancer: CMF vs. CMF + tamoxifen in a single centre.

The purpose of a randomized trial achieved in a single centre (Fondation Bergonié, Bordeaux, France) was to compare chemotherapy alone (intravenous CMF) versus chemotherapy and hormonotherapy (CMF plus tamoxifen-30 mg per day during 2 years), for patients with stage II breast carcinoma and positive values of estrogen and/or progesterone receptor (EPR) (greater than 10 and greater than 15 fmoles mg protein-1 respectively). Three hundred and thirty four women treated by surgery +/- radiotherapy are included in this trial from 06.01.81 to 12.31.84. No patient is lost for follow-up. Eight are excluded. Three hundred and twenty six patients are evaluable with a 38 month median follow-up. For EPR assay, the dextran charcoal micromethod was used in the same centre. The two groups are identical as far as age, hormonal status, TNM, EPR values, and histological features are concerned. Analysis of results shows a significant improvement of relapse free survival (p = 0.018) and also overall survival (p = 0.04) for the CMF+ tamoxifen group.

Adult↗