Marcelo Seixo de Brito e Silva

Use of chitosan membrane associated with polypropylene mesh to prevent peritoneal adhesion in rats.

The correction of wall abdominal defects often requires the use of implants such as polypropylene meshes. In spite of presenting good tissue acceptance, these biomaterials can migrate to adjacent viscera, promote enterocutaneos fistulas, tissue adherence and visceral erosions. In this work, the barrier effect of chitosan films associated with polypropylene meshes on adhesion formation experimentally induced in Wistar rats was evaluated. The animals were divided into two groups with 10 animals each. Animals in the CPP group were implanted with chitosan films associated with polypropylene meshes, whereas the ones in the PP group received only polypropylene meshes. After 8 days, the animals were submitted to euthanasia using CO(2) and a descriptive study focusing adhesion formation, visceral involvement with sutures and mesh peritonization was performed. Also, subimplanted material was collected for histopathology analysis. The results showed that the CPP group presented weak adhesions to the omentum over the stitch knots in eight animals. In all animals, the meshes were peritonized, not allowing their visualization after removing the chitosan films. In the PP group, six animals presented intestinal adhesions to the meshes and, in one of them, hepatic adhesion to the mesh was observed, besides omentum adhesion on more than 50% of the mesh area. The protective effect of chitosan films when sutured over polypropylene meshes, as well as no exacerbation of inflammation associated to the peritoneal lesions was statistically demonstrated. Therefore, chitosan films can indeed minimize the formation of peritoneal adhesions induced by polypropylene meshes in rats.

Avaliação do efeito da clorpromazina sobre a função renal de cães submetidos à isquemia e reperfusão

Renal ischemia may occur in different situations such as vascular or renal surgery and also in renal transplantation. This study evaluates renal function in dogs submitted to ischemia and reperfusion after chlorpromazine application. Twelve adult mongrel dogs were distributed into two groups with six animals each. Group A was composed of dogs submitted to renal ischemia and reperfusion without previous administration of chlorpromazine. Group B was composed of dogs with renal ischemia and reperfusion previously treated with chlorpromazine. In order to evaluate the possible ischemia/reperfusion late effects, blood and urine samples were sampled in four different times: Before ischemia, early stages of reperfusion, 120 minutes after reperfusion, and every week until 28th day postsurgery. Renal function was evaluated by clinical examination, serum urea and creatinine levels and urinary GGT activity. PU/CU and GGT urinary activity were more sensitive in detecting acute tubular injury than routine urine examination because these variables showed earlier changes. Based on urinalysis, urea and creatinine serum levels plus urinary excretion of GGT and PU/CU, no evidences of protective action of chlorpromazine were observed.

Evaluation of peritoneal adhesions formation and tissue response to polypropylene - poli (2-hydroxyethyl methacrylate)-(polyHEMA) implant on rats' abdominal wall.

PURPOSE To verify if the composit poli (2-hydroxyethyl methacrylate)-PolyHEMA/polypropylene mesh implanted in the female rats abdominal wall could be suitable for the prevention of peritoneal adhesions, and for the evaluation of the tecidual response produced by this biomaterial. METHODS Polypropylene meshes (Group PP, n=20) and polypropylene meshes coated with a layer of poli (2-hydroxyethyl methacrylate)-PolyHEMA (Group PH, n=20) were implanted on the abdominal wall of Wistar female rats. Ten animals from each group were submitted to euthanasia at 15 and 30 days of the postoperative period. RESULTS The animals from the group PP presented visceral adhesions on the mesh surface, which was not observed in the ones from group PH. At the histopathological examination foreign body response was observed in both groups, whilst there was a greater intensity of inflammatory response in group PH on both moments. CONCLUSION The poli (2-hydroxyethyl methacrylate) polyHEMA hydrogel associated to polypropylene mesh reduces visceral adhesion formation in rats, although it may be associated to greater inflammatory reaction.

Evaluation of Cell Growth Characteristics on Chitosan-Alginate Membranes to Assess Their Potential Application on Highly Exuding Skin Lesions and In Vivo Evaluation in Wounded Cat

Chitosan and alginate are non-toxic, biocompatible and biodegradable polysaccharides, used in skin healing. High biocompatibility, ease of production and low cost have increased the interest in the use of both compounds in medical and pharmaceutical sectors, as components of wound dressings. The purpose of this work was to access the use of chitosan and chitosan-alginate membranes for highly exudating wounds, as the ones normally observed in cats, employing Vero cell cul- ture as an initial evaluation step. The achieved results show that the chitosan-alginate membranes stimulated cell proliferation, but not cell adhesion, whereas improving tridimentional growth with the formation of aggregates. Cell concentration both at 24 and 48 h were similar to those observed in the control samples, however, at the 72-h period, the average number of cells was lower than those in the controls. The in vivo performance evaluation of the membranes indicated that they were effective on protecting the wound from external microbial contamination, also stimulating tissue recovery. The lesion was totally healed after 30 days.

2-hydroxyethyl methacrylate composite - polypropylene mesh for preventing peritoneal adhesions in female dogs.

PURPOSE To evaluate whether the lining facing the visceral side of polypropylene mesh made with 2-hydroxyethyl methacrylate (p(HEMA)) hydrogel could avoid peritoneal adhesion in female dogs. METHODS Eight animals (group PP) had a polypropylene mesh implanted to correct a defect in the rectal abdominal muscle, whereas in the other group (group PH) the polypropylene mesh was coated with p(HEMA) composite on the surface facing the peritoneal area. RESULTS Adhesions were observed on the mesh in 62.5% of the PP group. In the PH group adhesions were present only on the suture lines. CONCLUSION p(HEMA) hydrogel was well tolerated and effective in avoiding visceral and omental adhesions on the surface of the polypropylene mesh.

PREVALÊNCIA DO NÍVEL DE FORMAÇÃO DA VEIA CAVA CAUDAL NO CÃO

A veia cava caudal no cao e a via de drenagem do sangue, advindo da pelve e membros posteriores. O nivel de uniao das veias iliacas comuns, direita e esquerda formando a veia cava caudal pode apresenta variacao. Este trabalho teve como objetivo, avaliar a prevalencia do nivel de formacao da veia cava caudal do cao. Foram utilizados 104 caes, sem raca definida, de ambos os sexos, fixados em formol, dissecados e analisados macroscopicamente quanto ao nivel de formacao da veia cava caudal. A veia cava caudal apresentou-se com frequencia de formacao de 1,93% ao nivel das vertebras lombares L3 e L6 e com prevalencia de 95,19% ao nivel da setima vertebra lombar. As veias circunflexas iliacas profundas, direita e esquerda apresentaram drenagem para a veia cava caudal, ambas cranialmente ao nivel de sua formacao, em 92,31% dos casos e de 3,85% ao nivel desta formacao. Estes vasos tambem se apresentaram com drenagem, ambas para as veias iliacas comuns (2,89%), ou ainda em 0,96% dos casos com a veia circunflexa iliaca profunda direita para veia cava caudal, e a veia circunflexa iliaca profunda esquerda para a veia iliaca comum esquerda. Em 1,93% ocorreu uma ponte de ligacao entre as veias iliacas comuns, direita e esquerda. Portanto, a formacao da veia cava caudal do cao oscila entre L3 e L7, com maior frequencia neste ultimo nivel. As veias circunflexas iliacas profundas drenam cranialmente ou ao nivel da formacao da veia cava caudal, porem, ainda que em menor frequencia, para uma ou ambas as veias iliacas comuns. Nao houve indicios de que, estas variacoes no nivel de formacao da veia cava caudal, determinem prejuizos na drenagem da pelve e membros posteriores de caninos. 10.5216/ref.v6i4.8788