Intestinal Tumorigenesis Is Not Affected by Progesterone Signaling in Rodent Models

Clinical data suggest that progestins have chemopreventive properties in the development of colorectal cancer. We set out to examine a potential protective effect of progestins and progesterone signaling on colon cancer development. In normal and neoplastic intestinal tissue, we found that the progesterone receptor (PR) is not expressed. Expression was confined to sporadic mesenchymal cells. To analyze the influence of systemic progesterone receptor signaling, we crossed mice that lacked the progesterone receptor (PRKO) to the ApcMin/+ mouse, a model for spontaneous intestinal polyposis. PRKO-ApcMin/+mice exhibited no change in polyp number, size or localization compared to ApcMin/+. To examine effects of progestins on the intestinal epithelium that are independent of the PR, we treated mice with MPA. We found no effects of either progesterone or MPA on gross intestinal morphology or epithelial proliferation. Also, in rats treated with MPA, injection with the carcinogen azoxymethane did not result in a difference in the number or size of aberrant crypt foci, a surrogate end-point for adenoma development. We conclude that expression of the progesterone receptor is limited to cells in the intestinal mesenchyme. We did not observe any effect of progesterone receptor signaling or of progestin treatment in rodent models of intestinal tumorigenesis

Implantação de um programa de controle de qualidade de um acelerador linear de 6 MeV de fótons Implementation of a quality control program for a 6 MeV linear photon accelerator

Este trabalho apresenta a parte operacional do processo final envolvido na implantação de um programa de controle de qualidade por meio de testes rotineiros mecânicos e de radiação. O programa de controle de qualidade, durante 35 meses, mostrou a estabilidade excelente deste acelerador.<br>This paper describes the operational characteristics of the final process of implementation of a quality control program using routine mechanical and radiation tests. The quality control program was performed during 35 months and demonstrated the excellent stability of this accelerator

Prevenção da xerostomia e da mucosite oral induzidas por radioterapia com uso do laser de baixa potência Low level laser therapy in the prevention of radiotherapy-induced xerostomia and oral mucositis

OBJETIVO: Verificar se o uso do laser de InGaAlP com comprimento de onda de 685 nm pode reduzir a incidência de xerostomia, gravidade da mucosite oral e da dor associada à mucosite em pacientes portadores de câncer de cabeça e pescoço submetidos a radioterapia. MATERIAIS E MÉTODOS: Sessenta pacientes portadores de carcinoma de cabeça e pescoço foram submetidos a radioterapia com dose diária de 1,8 a 2,0 Gy e dose final de 45 a 72 Gy. O volume salivar foi medido nos dias um, 15, ao final do tratamento e após 15 e 30 dias, e a mucosite oral em avaliações semanais. Vinte e nove pacientes se submeteram a radioterapia sem laser e 31 foram submetidos a radioterapia e laser com dose diária de 2 joules/cm&sup2; em pontos pré-determinados da mucosa oral e glândulas parótida e submandibular. RESULTADOS: No grupo submetido a radioterapia e laser, a incidência de mucosite (p < 0,001) e dor (p < 0,016) foram significativamente menores e o volume salivar se manteve maior (p < 0,001) durante e após o tratamento. CONCLUSÃO: Os pacientes submetidos à associação de radioterapia e laser tiveram menor incidência de xerostomia, mucosite oral e dor quando comparados ao grupo de radioterapia sem laser, com resultados com significância estatística.<br>OBJECTIVE: To verify if the use of InGaAIP laser with 685 nm wave length can reduce the xerostomy incidence, the oral mucositis severity and the pain related to mucositis in patients with head and neck cancer submitted to radiotherapy. MATERIALS AND METHODS: Sixty patients presenting head and neck carcinoma were submitted to radiotherapy with daily doses of 1.8 to 2.0 Gy and a final dose of 45 to 72 Gy. The salivary volume was evaluated in the first and fifteenth days, at the end of the treatment and after 15 and 30 days. The oral mucositis was evaluated on a weekly basis. Twenty-nine patients were submitted to radiotherapy without laser and 31 were submitted to radiotherapy and laser with daily doses of 2 joules/cm&sup2; in predetermined areas of the oral mucosa and the parotid and submandibular glands. RESULTS: In the group submitted to radiotherapy and laser the incidence of mucositis (p < 0.001) and pain (p < 0.016) was significantly lower and the salivary volume (p < 0.001) was kept higher during and after the treatment. CONCLUSION: The group of patients submitted to radiotherapy and laser had lower incidence of xerostomy, oral mucositis and pain when compared to the group treated with radioteraphy without laser, producing statistically significant results