Morphometry of megakaryocytes in the liver of New Zealand White rabbits during intrauterine and postnatal development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of thrombopoietic activity through the quantification of megakaryocytes in bone marrow cytology and reticulated platelets

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Amifostine does not prevent activation of TGF beta 1 but induces smad 7 activation in megakaryocytes irradiated in vivo

Experiments were undertaken to assess the role of amifostine in the activation of latent TGFbeta1 and in the smad proteins cascade (smad 2/3, smad4, smad7), focusing on megakaryocytes, in the bone marrow irradiated in vivo. Non-irradiated megakaryocytes were negative for active TGFbeta1. Immunopositivity to active TGFbeta1 was detected in megakaryocytes 10 days after irradiation in amifostine- treated and untreated marrows. Smad 2/3 and smad 4 were strongly positive in the nucleus of megakaryocytes 10 days after irradiation. At the same time, a predominant hypocellular bone marrow with foci of hematopoiesis was observed with few megakaryocytes. An increase in the number of reticulin fibers was also seen. In amifostine-treated marrows, smad 2/3 and smad4 were not detected in the nucleus but were positive in the cytoplasm of megakaryocytes 10 days after irradiation. Coincidentally, bone marrows were cellular with megakaryocytes. Smad7 immunoexpression was detected in the cytoplasm of megakaryocytes in the non-irradiated, amifostine-treated and in the irradiated, amifostine-treated marrows. Data indicate that amifostine does not prevent latent TGFbeta1 activation in irradiated megakaryocytes. While TGFbeta1 signal transduction occurs in megakaryocytes in untreated bone marrows, it is inhibited in megakaryocytes in amifostine-treated marrows due to the induction of smad 7 activation. This is the first report showing smad 7 activation by amifostine. Our results also suggest a role for TGFbeta1 as an inhibitor of megakaryocytes in vivo. (C) 2002 Wiley-Liss, Inc.

Extramedullary hematopoiesis in a case of benign mixed mammary tumor in a female dog: cytological and histopathological assessment

Backgroud: Extramedullary hematopoiesis (EMH) is defined as the presence of hematopoietic stem cells such as erythroid and myeloid lineage plus megakaryocytes in extramedullary sites like liver, spleen and lymph nodes and is usually associated with either bone marrow or hematological disorders. Mammary EMH is a rare condition either in human and veterinary medicine and can be associated with benign mixed mammary tumors, similarly to that described in this case.Case presentation: Hematopoietic stem cells were found in a benign mixed mammary tumor of a 7-year-old female mongrel dog that presents a nodule in the left inguinal mammary gland. The patient did not have any hematological abnormalities. Cytological evaluation demonstrated two distinct cell populations, composed of either epithelial or mesenchymal cells, sometimes associated with a fibrillar acidophilic matrix, apart from megakaryocytes, osteoclasts, metarubricytes, prorubricytes, rubricytes, rubriblasts, promyelocytes, myeloblasts. Histological examination confirmed the presence of an active hematopoietic bone marrow within the bone tissue of a benign mammary mixed tumor.Conclusions: EMH is a rare condition described in veterinary medicine that can be associated with mammary mixed tumors. It's detection can be associated with several neoplastic and non-neoplastic mammary lesions, i.e. osteosarcomas, mixed tumors and bone metaplasia.

In vitro detection of hepatitis C virus in platelets from uninfected individuals exposed to the virus

Introduction ,,,,,Despite hepatocytes being the target cells of hepatitis C virus (HCV), viral ribonucleic acid RNA has been detected in other cells, including platelets, which have been described as carriers of the virus in the circulation of infected patients. Platelets do not express cluster differentiation 81 CD81, the main receptor for the virus in hepatocytes, although this receptor protein has been found in megakaryocytes. Still, it is not clear if HCV interacts with platelets directly or if this interaction is a consequence of its association with megakaryocytes. The aim of this study was to evaluate the interaction of HCV with platelets from non-infected individuals, after in vitro exposure to the virus. ,,,, ,,,, ,,,,,Methods ,,,,,Platelets obtained from 50 blood donors not infected by HCV were incubated in vitro at 37°C for 48h with serum containing 100,000IU∕mL of genotype 1 HCV. After incubation, RNA extracted from the platelets was assayed for the presence of HCV by reverse transcription – polymerase chain reaction RT-PCR. ,,,, ,,,, ,,,,,Results ,,,,,After incubation in the presence of virus, all samples of platelets showed HCV RNA. ,,,, ,,,, ,,,,,Conclusions ,,,,,The results demonstrate that, in vitro, the virus interacts with platelets despite the absence of the receptor CD81, suggesting that other molecules could be involved in this association.

IMMUNOHISTOCHEMICAL CHARACTERIZATION OF PROBABLE INTRAVASCULAR HEMATOPOIESIS IN THE VASA RECTAE OF THE RENAL MEDULLA IN ACUTE TUBULAR-NECROSIS

Immunohistochemistry was applied to identify the nature of the nucleated cells that accumulate in the vasa rectae of the corticomedullary junction in acute tubular necrosis. In all 6 cases studied, there were intravascular cells that reacted with monoclonal antibodies to erythroblast, macrophages, myeloid cells, T and B lymphocytes and rave megakaryocytes. The findings are consistent with the occurrence of intravascular haematopoiesis in the renal medulla in acute tubular necrosis.

Immunohistochemical characterisation of probable intravascular haematopoiesis in the vasa rectae of the renal medulla in acute tubular necrosis

Immunohistochemistry was applied to identify the nature of the nucleated cells that accumulate in the vasa rectae of the corticomedullary junction in acute tubular necrosis. In all 6 cases studied, there were intravascular cells that reacted with monoclonal antibodies to erythroblast, macrophages, myeloid cells, T and B lymphocytes and rare megakaryocytes. The findings are consistent with the occurrence of intravascular haematopoiesis in the renal medulia in acute tubular necrosis.

Interdisciplinary approach to treat dyskeratosis congenita associated with severe aplastic anemia: A case report

This paper reports on a 4-year-old male who had dyskeratosis congenita and who acquired severe aplastic anemia. The patient developed hyperpigmentation of the face, neck and chest region, arms, shoulders and legs. In addition, he had dry skin, deformed fingernails and toenails, sparse hair and eyebrows and hyperkeratosis of the dorsum of the hands and feet. Laboratory and histological analysis revealed severe pancytopenia and dyserythropoiesis of red blood cells, hypocellularity of white blood cells and decreased megakaryocytes with dysplasia. The intraoral examination identified bleeding gums; petechiae of the palate, tongue and cheek mucosa; and an atrophic, smooth and shining dorsal surface of the tongue. There were deep carious lesions in the deciduous mandibular molars and maxillary anterior teeth; as well as mobility of mandibular left canine, which had bone loss. The treatment for oral lesions included diet changes, improved oral hygiene, and extraction of the deciduous teeth destroyed by caries.

Detecção in vitro da hepatite C (VHC) em plaquetas provenientes de indivíduoas não infectados expostas ao vírus

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Plaquetas reticuladas na avaliação da trombopoiese medular em cães

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da infecção de megacariócitos e plaquetas pelo VHC e sua influência na fisiopatologia da hepatite C

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB