Spontaneous medullary thyroid carcinomas (MTCs) of old rat thyroids were analyzed for the expression of somatostatin and somatostatin binding sites in tumoral C cells in relation to the stage of tumor development, the mitotic activity of tumoral tissue and calcitonin biosynthesis as a marker of C cell differentiation. High levels of both immunoreactive somatostatin and its mRNA were detected in a subpopulation of tumoral C cells, gathered in areas suggesting a clonal proliferation and located preferentially at the periphery of the tumor. These cells also displayed high levels of calcitonin and its mRNA. However, many calcitonin immunoreactive cells showed no sign of somatostatin synthesis. The proliferative activity of the somatostatin-containing areas was low and slow compared to the areas lacking somatostatin production. However, it increased during the course of tumor growth. Somatostatin binding sites, measured with in vitro receptor autoradiography using 125I-[Tyr3]-octreotide or 125I-[Leu8, dTrp22, Tyr25]SS-28, were not detected in any of the MTCs tested. In rat MTC cells, somatostatin was associated with differentiation and slow proliferation, two parameters inversely correlated with the progression of malignancy. As expected, owing to the highly regulated secretion of the differentiated endocrine cell type, its presence was correlated with low basal calcitonin levels. However, the absence of somatostatin binding sites on any type of MTC cells does not favor a direct autocrine regulation of this peptide in this murine model of human MTC.

The purpose of this study was to evaluate practices and knowledge on infectious hazards, to determine the prevalence of viral hepatitis B and C related to occupational blood exposures among health care workers, and to propose a prevention policy. This descriptive epidemiological survey, which is multicentric and cross-cutting, was carried out in 2005 in four Moroccan cities. 1562 health care workers were contacted and 1002 accepted to reply to the questionnaire (64.1%). The mean age was 39.5 +/- 6.8 years and length of service 12.6 +/- 8.3 years. Blood was identified as the product most handled by workers (91.3%), followed by dirty linen and hospital waste. The most frequently used instruments reported were hollow needles (77.9%), followed by lancets. Re-sheathing used needles was practiced by 47.3% of the personnel. Nurses, assistants and support staff have insufficient knowledge on how viral hepatitis B and C is transmitted. Only 47.4% of personnel were adequately vaccinated against hepatitis B. Post-vaccines serology was carried out on only 2.7% of the vaccinated staff. During the last twelve months, 62.8% of the persons were victim to at least one occupational blood exposures of which 8.3% were reported. Universal precautions are not widely known or applied: only 24.4% wore gloves for invasive acts and 63% correctly disinfected their hands. Viral hepatitis B and C hazards in healthcare facilities are not sufficiently taken account. The recent creation of occupational health services in hospital facilities should contribute to improve working conditions, provide for mandatory vaccination of hospital employees against viral hepatitis B, and improve and increase information and education on hazards related to occupational blood exposures for healthcare personnel.

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