ABSTRACT
PURPOSE: To investigate the carcinogenic action of hydrochloric acid, pepsin and sodium nitrate on the oropharyngeal mucosa of rats, simulating the reflux of gastric contents. METHODS: Eighty-two Wistar rats were divided in seven groups and submitted to 2 or 3 weekly applications of hydrochloric acid, pepsin and sodium nitrate on the pharyngeal mucosa during six months. Study groups comprised 12 animals each. Rats in groups I and II were submitted to 2 (GI) or 3 (GII) weekly applications of 0.1N hydrochloric acid. Groups III and IV were submitted to 2 (GIII) or 3 (GIV) weekly applications of 0.1N hydrochloric acid solution with pepsin. Groups V and VI were submitted to 2 (GV) or 3 (GVI) weekly applications of 0.1N hydrochloric acid and treated with daily nitrate diluted in water. Group VII consisted of 10 animals submitted to 2 weekly applications of filtered water. RESULTS: No dysplasia, intra-epithelial neoplasia or invasive carcinomas were detected. Inflammatory changes were observed in varying degrees and mast cells were more common in Groups V and VI (p=0.006). CONCLUSION: The data of the current study could not corroborate the hypothesis that gastroesophageal and pharyngolaryngeal refluxes are carcinogenic factors to the laryngopharyngeal mucosa, and more studies are necessary in the future.
OBJETIVO: Investigar a ação carcinogênica do ácido clorídrico, pepsina e nitrato de sódio na mucosa orofaríngea de ratos, simulando o refluxo do conteúdo gástrico à mucosa do faringo-laringea. MÉTODOS: Oitenta e dois ratos Wistar foram divididos em 7 grupos e submetidos a 2 ou 3 aplicações semanais de ácido clorídrico, pepsina e nitrato de sódio na mucosa orofaríngea durante 6 meses. Os grupos de estudo envolveram 12 animais cada. Os ratos nos grupos I e II foram submetidos à 2 (GI) ou 3 (GII) aplicações semanais de ácido clorídrico 0,1N. Nos grupos III e IV foram 2 (GIII) ou 3 (GIV) aplicações semanais de ácido clorídrico e pepsina. Nos grupos V e VI foram 2 (GV) ou 3 (GVI) aplicações semanais de ácido clorídrico além da oferta de nitrato diluído em água diariamente. Grupo VII era composto por 10 animais submetidos a 2 aplicações semanais de água filtrada. RESULTADOS: Não se observou displasia, neoplasia intra-epitelial ou neoplasia invasora. Alterações inflamatórias em graus variados foram observadas, com infiltrado mastocitário mais intenso nos grupos V e VI. (p=0,006). CONCLUSÃO: Os dados do presente estudo não confirmam a hipótese que o refluxo gastro-esofágico e faringo-laringeo são fatores carcinogênicos para a mucosa laringo-faringea e mais estudos são necessários no futuro.
Subject(s)
Animals , Male , Rats , Carcinogens/toxicity , Carcinoma, Squamous Cell/chemically induced , Gastrointestinal Agents/toxicity , Hydrochloric Acid/toxicity , Nitrates/toxicity , Oropharyngeal Neoplasms/chemically induced , Carcinogenicity Tests , Carcinoma, Squamous Cell/pathology , Drug Evaluation, Preclinical , Mouth Mucosa/pathology , Oropharyngeal Neoplasms/pathology , Pepsin A/toxicity , Random Allocation , Rats, WistarABSTRACT
A hospital based, group matched case control study was conducted with the objective to assess the association between tobacco consumption practices and risk of development of oro-pharyngeal cancer in Central India. The study included 123 cases of oro-pharyngeal cancer, diagnosed on the basis of histopathology at three tertiary care centers in Nagpur city. Each case was matched for age and sex with two hospital controls: one selected from non-cancer patients and another from patients having cancer of other sites. Tobacco chewing (OR=7.98, 95% CI 4.11-13.58) and tobacco smoking (OR=2.25, 95% CI 1.22-3.70) were found to be significantly associated with oro-pharyngeal cancer on unconditional multiple logistic regression analysis. Further analysis revealed a dose-response relationship between increasing frequency, duration and retention time of tobacco in mouth and risk of oro-pharyngeal cancer. Other risk factors which were also found to contribute significantly in the outcome of oro-pharyngeal cancer in the study population were: use of traditional/local substances (eg pan, betel nut, lime) with or without tobacco, use of tobacco containing material for teeth cleaning, type of smoking (eg bidi, chillum, cigarette) and outdoor occupations. High values of estimates of attributable risk percent (ARP) and population attributable risk percent (PARP) confirmed the positive impact of reduction or elimination of the tobacco consumption practices on reducing the risk of oro-pharyngeal cancer in the population of Central India.
Subject(s)
Adult , Analysis of Variance , Case-Control Studies , Female , Humans , Incidence , India/epidemiology , Logistic Models , Male , Middle Aged , Odds Ratio , Oropharyngeal Neoplasms/chemically induced , Plants, Toxic , Risk Factors , Smoking/adverse effects , Tobacco, Smokeless/adverse effectsABSTRACT
La mayoría de ensayos in vitro para realizar pruebas de quimiosensibilidad se han desarrollado utilizando metodología relativamente compleja, sin la obtención de resultados favorables. Desarrollamos una prueba de quimiosensibilidad, in vitro, para cánceres humanos y la aplicamos en 8 biopsias de tumores de cabeza y cuello, cultivándolas por medio de la técnica de explante primario en medio líquido, y agregando distintos fármacos (Actinomivins D, Adriamicina, Bleomicina, Cisplatino, 5-Fluoruracilo, Metotrexate, Mitomicina C, Vinblastina y Vicristina) a concentraciones variadas. Se observó un 100 por ciento de eficacia de proliferación celular en ausencia de fármacos, así como una inhibición diferente que dependía de la droga citotóxica empleada. Algunos explantes fueron altamente inhibidos mientras que otros resultaron muy resistentes, esta variabilidad de respuesta se obtuvo en distintos explantes aún cuando se utilizaba el mismo fármaco. Metrotexate demostró tener una alta selectividad inhibitoria para los explantes de crecimiento rápido, mientras que Bleomicina, a dosis bajas, para los de crecimientos lento.