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Biomedical subjects

C Chenal

Publications and source records attributed to C Chenal.

44 records · Page 3Linked to original sources
PubMedDate not supplied

[Radiotherapy of stage T1-T2 M0 prostatic adenocarcinoma. Analysis of the carcinologic results of a multicenter study of 610 patients. Groupe Radiothérapie de la Commission de Coopération Médicale Intercentres (CCMI)].

PURPOSE: Retrospective analysis of the results of radiotherapy in localized prostatic adenocarcinoma. Complications were excluded. PATIENTS AND METHODS: Six-hundred-and-ten T1-T2 adenocarcinomas of the prostate were treated with continuous courses of external beam radiation therapy in 19 participating Institutes between January 1983 and January 1988. The mean follow-up was 10.4 years; the mean age of patients at the beginning of radiotherapy was 68.5 years. RESULTS: A 10-year, local control had been achieved in 86% of T1-T2 (81.4% for T2). The 5- and 10-year metastatic relapse rates were 25.3% and 30% (29% and 38.1% for T2), respectively. At 10 years, 62.4% of T1-T2 were recurrence-free; overall survival rate was 45.8% and cause-specific survival rate was 70.5%; 29.9% of T1-T2 patients were alive and disease-free. T category (TNM), pathologic grade, pelvic lymph node status, local tumor control, and obstructive ureteral symptoms were correlated with survival. The influence of pelvic nodes radiation, dose, overall treatment time, previous endocrine treatment, and transuretral resection was not significant for disease-free survival (alive and disease-free) and other endpoints. CONCLUSION: There was no difference between the French series (1975-1982 and 1983-1988). The results of the literature are comparable to ours. As far as prognostic factors are concerned, this report provides evidence that the explainable variables which influence survival depend on the tumor and patient status.

Adenocarcinoma↗
PubMedDate not supplied

Genomic instability and breast cancer.

The loss of genomic stability is accepted as being one of the most important aspects of cancer. The correlation between genomic instability and cancer proneness in cases of known genetic syndromes (e.g. ataxia telengectasia, Fanconi anemia) is well established. This study was conducted to assess genomic instability in 19 patients with sporadic breast cancer. We used the comet assay on the lymphocytes of patients before radiotherapy and/or chemotherapy. The alkaline comet assay (single-cell gel electrophoresis) is a sensitive and rapid method for detecting DNA damage (single strand breaks and alkali-labile sites) in G(0) cells, at a single-cell level. This assay was achieved in vitro without irradiation and after exposure (dose ranging from 50 cGy to 5 Gy). The results show that the patients have higher baseline values than controls. At 2 Gy, the mean tail moment, score and the percentage of DNA in the tail increase for both groups but these values are much higher for patients. Our results show that the lymphocyte DNA of cancer patients is more damaged than that of controls with or without irradiation. Our hypothesis is that this baseline DNA damage reflect a genomic instability in sporadic breast cancer. This instability seems to increase after in vitro irradiation.

Aged↗
PubMedDate not supplied

Exposition of humans to low doses and low dose rate irradiation: an urgent need for new markers and new models.

In human radiation protection, the shape of the dose effects curve for low doses irradiation (LDI) is assumed to be linear, extrapolated from the clinical consequences of Hiroshima and Nagasaki nuclear explosions. This extrapolation probably overestimates the risk below 200 mSv. In many circumstances, the living species and cells can develop some mechanisms of adaptation. Classical epidemiological studies will not be able to answer the question and there is a need to assess more sensitive biological markers of the effects of LDI. The researches should be focused on DNA effects (strand breaks), radioinduced expression of new genes and proteins involved in the response to oxidative stress and DNA repair mechanisms. New experimental biomolecular techniques should be developed in parallel with more conventional ones. Such studies would permit to assess new biological markers of radiosensitivity, which could be of great interest in radiation protection and radio-oncology.

Dose-Response Relationship, Radiation↗
PubMedDate not supplied

[Radiation and the kidney (author's transl)].

The kidney is highly radiosensitive. Analysis of the literature indicates that the threshold dose is 2 350 rads in 5 weeks. A number of clinical examples are used to illustrate the precautions which must be taken by the radiotherapist in order to avoid the provocation of radiolesions whilst delivering a curative dose to the tumor.

Acute Disease↗
PubMedDate not supplied

Experimental colonic carcinogenesis: a new animal model.

The aim of this work was to develop an animal model of accessible colonic tumours simulating human carcinogenesis. A segment of the colon was exteriorized to the skin in 60 rats and swabbed with N-methyl-N-nitrosourea. All the animals developed tumoral abnormalities or frank dysplasic tissue 7 months after the beginning of the experiment. This animal model which closely mimics human colonic carcinogenesis is particularly interesting because tumour development can be monitored in live animals without interrupting normal intestinal functions.

Animals↗