Histology and histopathology Vol.16, nº 1 (2001)
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- PublicationOpen AccessImmunohistochemical expression of p53 in animal tumors: a methodological study using four anti-human p53 antibodies(2001) Albaric, O.; Bret, L.; Amardeihl, M.; Delverdier, M.Mutations in the p53 tumor suppressor gene are the most common genetic alterations in human cancers. These mutations usually lead to strongly enhanced protein stabilization and allow detection by immunohistochemistry. Two monoclonal (DO-7 and PAb-240) and two polyclonal (Ab-7 and CM-l) antibodies were evaluated by standard immunoperoxidase method in domestic animal tumors, chiefly squamous cell carcinomas (Scq, and osteosarcomas as positive controls. Immunoreactivity was detected in SCC of cattle, sheep, horse and cat as well as in feline actinic keratosis, with PAb-240 and CM-l antibodies. One polyclonal antibody (Ab-7) did not give positive result at all, whereas DO-7 monoclonal antibody did not react in dogs and cats. Immunodetection of p53 protein is thus possible in all domestic species tested, especially with CM-l and PAb-240 antibodies, and p53 alterations seem to occur early in carcinogenesis of feli ne SCC as in comparable human lesions.
- PublicationOpen AccessFunction of inflammatory cells and neoral cyclosporin-A in heart transplant-associated coronary vasculopathy(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Buján, J.; Jurado, F.; Gimeno, M. J.; Rodriguez, M.; Bellón, J. M.The role of Sandimmun Neoral® (S-n) and the immune response in transplant-associated coronary vasculopathy (TACV) was evaluated in a Lewis (Lew)- to-Fischer-344 (F344) rat abdominal heterotopic heart transplant model. Some of the transplant recipients were treated with S-n (5mg/ kg/ day) for 14 days posttransplant, or until sacrifice. Grafts were subjected to immunohistochemical (ED1, CD4, CD8 and a-actin+ cells) anal ysis from day 7 to 100 post-transplant. Singenic controls did not develop TACV, irrespective of whether they had received the drug or not. TACV was detected in Lew-F344 transplants regardless of S-n administration with participation of ED1+, CD8+ and aactin+ cells, although its incidence was lower in animals receiving prolonged S-n treatment. In this model, accelerated arteriosclerosis of the graft appeared to be related more to the rejection effect than to the action of the immunosuppressive agent.
- PublicationOpen AccessMicroglial reaction in focal cerebral ischaemia induced by intra-carotid homologous clot injection(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Ng, Y.-K.; Ling, E.-A.This study examined the microglial reaction in a simulated thrombo-embolus ischaemia in rats given an intracarotid injection of a suspension of homologous blood clot. All rats including the controls receiving vehicle injection were perfused at 5 hours, and 1, 3 and 7 days post-operation. The brains were removed and processed for immunohistochemistry using a panel of monoclonal antibodies: OX-42, OX-18 and OX-6 for labeling of microglia. In rats given saline injection OX42 immunoreactive microglial cells were observed to be distributed quite evenly throughout the whole brain. When injection of clot suspension was given, microglial cells responded vigorously, particularly in the ipsilateral hippocampus. Microglial reaction was also detected in the ipsilateral cerebral cortex, caudate as well as septal nuclei. The majority of the detected reactive microglial cells were hypertrophied showing thick or stout processes. Some rod-like and amoeboid microglia were also observed. Rarely did the reactive microglia express OX-6 immunoreactivity. All microglial cells were unreactive for OX-18. The actual mechanisms leading to the microglial activation as well as functions of reactive microglia in focal cerebral ischaemia remain speculative. In the absence of direct evidence, it could only be suggested that they may act as sensor cells for detection of subtle alterations in the microenvironment, probably in response to focal ischaemia and/or leakage of serumderived factors induced by thrombo-embolus stroke.
- PublicationOpen AccessInvolvement of gap junctional communication and connexin expression in trophoblast differentiation of the human placenta(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Cronier, L.; Bastide, B.; Defamie, N.; Niger, C.; Pointis, G.; Gasc, J. M.; Malassine, A.Gap junctional intercellular communication (GJIC) permits coordinated cellular activities during development and d ifferentiation processes, and its dysfunction or mutation of connexin genes have been implicated in pathologies. In the human placenta, two distinct differentiation pathways of cytotrophoblastic cell coexist leading to a double model: fusion phenotype (villous trophoblast) a nd proliferative/ invasive phenotype (extravillous trophob last). This review focuses on current knowledge on the connexin expression and the implication of GJIC in trophoblastic differentiation. Experimental evidence obtained in human placenta demonstrates the involvement of connexin 43-gap junctions in the trophoblastic fusion process and of a connexin switch during the spatially and temporally controlled proliferation/invasion process.
- PublicationOpen AccessStudies on the involvement Histology and Histopathology Cellular and Molecular Biology of endogenous neuropeptides in the control of thymocyte proliferation in the rat(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Trejter, M.; Warchol, J. B.; de Caro, R.; Brelinska, R.; Nussdorfer, G. G.; Malendowicz, L. K.The possible involvement of endogenous vasoactive intestinal peptide (VIP), cholecystokinin (CCK) and neurotensin (NT) in the control of thymocyte proliferation ha s been investigated in vivo in the immature rat. For this task, we have studied the effects of the administration of selective antagonists of the receptors of the three neuropeptides on the mitotic index (%0 of metaphase-arrested cells after vincristin injection) of thymocytes. Both CCK- and TN-receptor antagonists were ineffective. In contrast, two VIP receptor antago nists (VIP-As) enhanced the mitotic index of thymocytes. VIP reversed the effect of VIP-As, but when administered alone it did not alter the mitotic activity of thymocytes. In light of these findings, we conclude that endogenous VIP exerts a maximal tonic inhibitory influence on the basal proliferative activity of rat thymocytes, while endogenous CCK and NT do not play a relevant modulatory role in thi process.