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Background/aim TLR-4 Knock-out (KO) mice are protected from colitis-associated cancer in the established AOM/DSS mouse model. The aim of this study was to assess whether the TLR4 KO mice would still be protected from carcinogenesis after platelet depletion and transfusion with TLR4 wild-type platelets. Materials and methods Thirty-two female C57BL6 mice were divided into 6 groups. Among the three groups that received Azoxymethane/Dextran Sulfate Sodium (AOM/DSS), one group included TLR4KO mice, which were depleted of their platelets and were then transfused with platelets from TLR4 wild-type mice. The other two groups included wild-type and TLR-4KO mice that only received AOM/DSS. Results All 6 animals in the KO group that underwent platelet depletion/transfusion succumbed. Three of them died before the administration of DSS and three in the week following DSS administration. In contrast, mice in the other two groups experienced less weight loss and only 1 mouse died in each of them. Conclusion Platelet depletion/transfusion was detrimental in TLR-4 transgenic mice that received AOM/DSS.

The hemorrhagic syndrome of leptospirosis was studied in guinea pigs. The study correlates hematological, histopathological and immunohistochemical alterations in sixty animals inoculated by the intraperitoneal route with lml of the culture of virulent strain of Leptospira interrogans serovar copenhageni. Leptospirae antigens were detected by immunoperoxidase, chiefly in liver, kidney and heart muscle capillaries. Possible pathogenic mechanisms responsible for hemorrhagic syndrome are discussed with emphasis on toxic and anoxic attacks causing damage to endothelia, platelet depletion and alterations to hemostasia rates: prothrombin time [FT], partial thromboplastin time [PIT] and fibrinogen concentrations. Tide clinical-laboratoiy picture is compatible with the histopathological observation of disseminated intravascular coagulation [D1C] in most of the guinea pigs from day 4 of infection.Os autores estudam a síndrome hemorrágica da leptospirose em cobaios inoculados com amostra virulenta de Leptospira interrogans sorovar copenhageni. São abordados aspectos hematológicos, hístopatolôgicos e imuno- histoquímicos. Aumento do tempo de protrombina (PT) e do tempo parcial tromboplastina (PTT), bem como redução do número de plaquetas e do fibrinogênio acompanharam-se de congestão vascular, hemorragias e coagulação intravascular no fígado, rim, coração, músculo esquelético e pulmão. O antígetzo de Leptospira foi detectado principalmente em tecido hepático, renal e cardíaco. São discutidos possíveis mecanismos patogênicos responsáveis pela síndrome hemorrágica, com ênfase na agressão tóxico- anóxica do endotêlio vascular, que propiciaria a instalação de coagulação intravascular disseminada (CIVD) observada, sobretudo, nos cobaios dos grupos 4, 5 e 6.

Background: Post-operative anastomotic insufficiency following major hepato-biliary surgery has significant impacts on the post-operative course. Recent reports have revealed that platelets play an important role in liver regeneration and wound healing. From these experimental and clinical results on platelet function, we hypothesized that post-operative platelet depletion (to