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A male 15-year-old captive Siberian tiger (Panthera tigris altaica) developed pelvic limb hypermetry over the past 10 years. Recently, an ulcerated black nodule located caudally to the right ear was observed. The animal was submitted to surgery for removing the tumor, but died during anesthetic recovery. At necropsy, another infiltrative nodule was observed caudally to the right ear. Histologically, both nodules corresponded to melanocytic neoplasia, varying from heavily pigmented to amelanotic, with metastasis to mediastinal lymph nodes, spleen and lung. Lipofuscinosis and corpora amylacea were histologically observed in the central nervous system. Macroscopic and histologic findings confirmed the diagnosis of skin metastatic melanoma in a captive adult Siberian tiger. RESUMO Um tigre-siberiano (Panthera tigris altaica) de cativeiro, macho, de 15 anos de idade, apresentou hipermetria dos membros pélvicos nos últimos 10 anos, e recentemente, foi observado um nódulo preto e ulcerado caudalmente à orelha direita. O animal foi submetido à cirurgia para remoção do nódulo e morreu durante a recuperação anestésica. À necropsia, outro nódulo infiltrativo, foi detectado caudalmente a orelha direita. Histologicamente, ambos os nódulos correspondiam à neoplasia melanocítica, com células variando de fortemente pigmentadas a amelanóticas, com metástase para linfonodos mediastinais, baço e pulmão. Havia lipofucsinose e corpora amilácea no sistema nervoso central. Os achados macroscópicos e histológicos confirmam o diagnóstico de melanoma cutâneo metastático em um tigre-siberiano adulto de cativeiro.

Studies in yeast have provided some clues to how cell size might be determined in unicellular eukaryotes; yet little attention has been paid to this issue in multicellular organisms. Reproducible cell sizes might be achieved in the dividing cells of multicellular organisms by the coordination of growth with cell division. Recently, mutations in genes encoding homologues of components of the mammalian insulin/phosphoinositide 3-kinase signalling pathway have been shown to affect organ growth and cell size during Drosophila melanogaster imaginal disc development. The data suggest that signalling through this pathway alters cell size because it primarily affects the growth of these organs (i.e. their increase in mass) and does not have a proportional impact on cell division. These observations are in keeping with the hypothesis that growth and cell division are regulated independently, and that cell size is just a consequence of the rate at which tissues grow and the cells within them divide. However, signalling through this pathway can affect cell cycle phasing and at least influence cell division. These interactions may provide a means of coordinating growth and cell division, such that cells divide only when they are above a minimum size.

Aims. Imunosuppression therapy for the control of immunologic rejection is a key aspect in liver transplantation. The objective of this study was to evaluate induction therapy with daclizumab (DAC) in living donor liver transplantation (LDLT) in children. Methods. We compared 2 different imunosuppression protocols in 30 children undergoing LDLT. The patients were divided into 2 groups: 12 patients received tacrolimus with mycophenolate mofetil (TAC-MMF), and 18 patients received tacrolimus with MMF and DAC induction therapy at days 0 and 14 after LDLT (DAC-TAC-MMF). Both groups were similar with regard to age, sex, weight, and indication for liver transplantation. The incidence of biopsy-proved rejection episodes, posttransplantation lymphoproliferative disease (PTLD), and renal dysfunction were evaluated. Tacrolimus levels at posttransplantation day 14 and at 2 months after transplantation were compared in the 2 groups. Results. Acute rejection episodes were observed in 8 patients in the TAC-MMF group (66%), and none in the DAC-TAC-MMF group (0%; P