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Background and Aim: Platelets provide many functions in the body, especially to the liver. The purpose of this study is to investigate the effect of thrombocytosis with acute hepatitis induced by anti-Fas antibody and its mechanism., Methods: Acute hepatitis was induced by administration of anti-Fas antibody in normal and thrombocytotic C57BL6J mice. For thrombocytosis, thrombopoietin; PEG-rHuMGDF was injected 5 days before and just prior to administration of anti-Fas antibody. To investigate the mechanisms, hepatocyte cell line (AML12) and sinusoidal endothelial cell line (M1) were induced apoptosis by staurosporine. They were cultured with platelets or thrombopoietin. Examination items were as follows: platelet number, alanine aminotransferase (ALT), histological findings, TUNEL (TdT-mediated dUTP-biotin Nick End Labeling) staining, and the expression of proteins associated with apoptosis in vivo and in vitro., Results: Platelets were significantly increased in the thrombocytotic group (P < 0.01). Serum ALT levels were significantly reduced by thrombocytosis at 6, 24 and 72 h after the administration (P < 0.05). In histological findings, hemorrhagic necrosis was observed in the normal group, but not observed in the thrombocytotic group. TUNEL-positive hepatocytes were reduced and the expression of cleaved caspase-3 was significantly decreased in the thrombocytotic group. The phosphorylation of Akt, the increment of Bcl-xL and the decrease of cleaved caspase-3 were observed in AML12 cells cultured with platelets, but were not observed cultured with thrombopoietin. Platelets and thrombopoietin had no anti-apoptotic effect on M1 cells., Conclusion: Increase of platelets has a preventative effect against acute hepatitis induced by the anti-Fas antibody. It is suggested that platelets have a direct protective effect against apoptosis of hepatocytes., (© 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)

Aims: The incidence, bone marrow morphology and genetic features of bcr+ essential thrombocythaemia were investigated., Methods and Results: Sixty-four consecutive patients meeting the criteria of essential thrombocythaemia have been investigated for bcr-abl rearrangement and chimera mRNA expression. Reverse transcriptase-polymerase chain reaction indicated bcr-abl expression in six patients, in two of whom large fraction of the blood and bone marrow cells proved to be positive for Philadelphia chromosome (Ph) by fluorescent in-situ hybridization (FISH) and conventional cytogenetic analysis. In the remaining four patients FISH analysis could not detect Ph+ cells among the blood cells, but in one of these four patients conventional cytogenetic analysis indicated a very small fraction (2%) of Ph+ mitoses in the bone marrow (bcr+ essential thrombocythaemia patients). In three of these four patients, X-chromosome-linked clonality assay showed that the disease is of uncommitted stem cell origin. During an average of 57 month long follow-up no transformation to chronic myeloid leukaemia type of disease or acceleration/blastic crisis could be observed in the four bcr+ essential thrombocythaemia patients. They did not differ significantly from typical essential thrombocythaemia patients in quantitative indices of bone marrow cellularity or the size of megakaryocytes. In these two parameters as well as in the total nucleolus organizer region area per nucleus, however, significant differences could be detected between these four as well as typical chronic myeloid leukaemia patients. Statistical analysis of the morphometric data obtained from all six Ph+ and bcr+ essential thrombocythaemia patients combined indicated a shift of the bone marrow morphology towards the chronic myeloid leukaemia type of myeloproliferation., Conclusions: These investigations indicate that bcr+ essential thrombocythaemia is infrequent among essential thrombocythaemia patients, and this condition resembles essential thrombocythaemia more than chronic myeloid leukaemia. Various expansions of the Ph+ clone appear to lead to either essential thrombocythaemia or, rather, chronic myeloid leukaemia type of myeloproliferation; however, data in the present study do not indicate that bcr+ essential thrombocythaemia would be a form fruste variant of chronic myeloid leukaemia.

Both bone marrow and peripheral blood was investigated light and electron microscopically in 3 cases with polycythemia vera, 2 cases with primary thrombocythemia and 1 case with panmyelosis. In 5 cases the peripheral blood showed persistent increase in cells of two or three hematopoietic systems. Giant thrombocytes in the peripheral blood were seen in 3 cases. Erythroblasts, granulocytic young forms, and megakaryocytes were often observed in the blood. Histologic bone marrow examination showed prominent proliferation of all 3 hematopoietic cells in every case. Cytological and electron microscopical examinations of the bone marrow revealed many mitotic figures, morphological abnormalities, and unbalanced nucleocytoplasmic maturation in various hematopoietic cells. These findings suggested that the proliferation of all 3 hematopoietic cells in the bone marrow was not simply reactive in nature, but an idiopathic progressive process. It is considered that these disorders and primary myelosclerosis represent no separate entities and must be unified as "chronic panmyelosis".

An autopsy case of severe thrombocytosis associated with cancer of gallbladder is described as the first case in the literature. A 78-year-old male patient was admitted to the hospital with abnormal hepatic functions on August 6, 1975. Laboratory examination revealed platelet count of 5,664,000/cu mm, anemia, leukocytosis and bilirubinemia. Jaundice was progressive and the patient died after a month. Severe thrombocytosis persisted throughout the course. Main autopsy findings were cancer of gallbladder with metastasis to the liver, fibrosis of spleen and purulent bronchopneumonia. A possible mechanism of unusually severe degree of thrombocytosis associated with the present case is discussed in light of the literature.