Is peritoneal reflection the best anatomical repair landmark in experimental colorectal surgery on rats? / A reflexão peritoneal é o melhor reparo anatômico na cirurgia experimental colorretal em ratos?

PURPOSE: To validate Peyer's patch as an anatomical repair landmark for colorectal surgery in rats and to measure the collagen content in segments of the colon containing or not containing Peyer's patch. METHODS: The distance between Peyer's patch and the peritoneal reflection was measured in forty-five Wistar rats. The colon and rectum were resected for quantification of collagen content by means of computer-assisted image analysis in regions of the colon with and without Peyer's patch. RESULTS: There was great variation in the distance between Peyer's patch and the peritoneal reflection when the male and female rats were considered as a single group (p=0.04). Comparison between the genders showed that the distance between the patch and the peritoneal reflection was greater in female than in male rats (p=0.001). The colonic segment containing Peyer's patch was observed to have lower tissue collagen content than the segment in which this structure was not present (p=0.02). CONCLUSION: Peyer's patch can be indicated as an anatomical repair landmark, and there is a need to study the healing of colorectal anastomoses in rats based on differing quantities of tissue collagen existing in the colonic wall with or without this structure.

OBJETIVO: Validar a placa de Peyer como reparo anatômico para a cirurgia colorretal em ratos e mensurar a quantidade de colágeno em segmentos da parede cólica que contém ou não a placa de Peyer. MÉTODOS: Foi aferida a distância entre a placa de Peyer e a reflexão peritoneal em 45 ratos Wistar. O cólon e o reto foram ressecados, para a quantificação do colágeno, por meio de análise de imagem assistida por computador, em regiões do cólon que continham ou não a placa de Peyer. RESULTADOS: Existe grande variação entre a distância da placa de Peyer e a reflexão peritoneal quando se consideraram os animais de ambos os gêneros como grupo único (p= 0.04), sendo a distância entre a placa e a reflexão peritoneal maior entre as fêmeas (p=0.001). Constatou-se que o segmento cólico que contém a placa de Peyer apresenta conteúdo menor de colágeno quando comparado ao segmento onde a estrutura não estava presente (p=0.02). CONCLUSÃO: A placa de Peyer pode ser indicada como reparo anatômico e no estudo da cicatrização de anastomoses colorretais em ratos, baseado nas diferentes quantidades de colágeno tecidual existente na parede cólica que contém ou não esta estrutura.

Expressions of p53 and p21 in Primary Gastric Lymphomas

The p21 overexpression is thought to be a consequence of the p53 induced activation of the p21 gene. The immunohistochemical evaluation of p53 and p21 can be a valuable means of assessing the functional status of the p53 gene product. We examined the overexpression of p21 and p53 proteins in primary gastric lymphomas and the correlation with prognosis. A total of 32 cases of gastric lymphomas was classified into low-grade lymphomas of mucosa-associated lymphoid tissue type (n=16) and high-grade B-cell lymphomas (n=16). In low-grade lymphomas, only one case showed p53 positivity and all cases were p21-negative. In high-grade lymphomas, seven cases were p53+/p21- (44%), one case was p53+/p21+ (6%), and eight cases were p53-/p21- (50%). The p53+/p21- cases had a much lower percentage of patients sustaining a continuous complete remission state (3/7, 43%) compared with other cases (6/7, 86%). From these results, we concluded that p21 expression is rare in primary gastric lymphomas. Therefore, p53-positive lymphomas can be assumed as having p53 mutation. And combined studies of p53 and p21 may be used as a prognostic indicator in primary gastric high-grade lymphomas.

Ultrastructural specialization of intestinal epithelium over Peyer's patches in the bonnet monkey, Macaca radiata.

The follicle associated epithelium (FAE) which separates the lymphoid follicle of Peyer's patch from the gut lumen is known to have specialized cells called M cells or "microfold" cells in man and certain animals. These cells are considered to be involved in antigen uptake and transport. Our light microscopic study of the small intestine of bonnet monkeys suggested the presence of such specialised cells in FAE. We have confirmed the presence of M cells in bonnet monkey FAE having ultrastructural features very similar to those of human M cells.