MPL immunohistochemical expression as a novel marker for essential thrombocythemia and primary myelofibrosis differential diagnosis.

To evaluate the grading of fibrosis and immunohistochemical expression of MPL in bone marrow biopsies of ET and PMF. Fibrosis in bone marrow biopsies (BMBs) was evaluated according to the European Consensus for grading of fibrosis, according to reticulin proliferation. Immunohistochemical analysis was performed in samples from 18 ET and 38 PMF patients: 19 were classified as pre-fibrotic and 19 were classified as fibrotic according to the World Health Organization (WHO) criteria, by means of the MPL antibody. Six bone marrow donors' biopsies were used as controls. Average reticulin (p<0.003) and MPL (p<0.008) values differed significantly between the ET group and the pre-fibrotic stage PMF group. The MPL immunohistochemical expression may represent a new marker for differential diagnosis between ET and pre-fibrotic stage PMF.

The relationship of the active and latent forms of TGF-ß1 with marrow fibrosis in essential thrombocythemia and primary myelofibrosis.

The aim of this study was to perform an immunohistochemical analysis from 100 megakaryocytes per sample, analyzing positivity and intensity levels of anti-LAP human TGF-ß1 (or Latent TGF-ß1) and anti-TGF-ß1 (or Active TGF-ß1) antibodies from 18 essential thrombocythemia (ET) and 38 primary myelofibrosis (PMF) patients (being 19 pre-fibrotic and 19 fibrotic). Six bone marrow donor biopsies were used as controls. Fibrosis in bone marrow biopsies (BMB) was evaluated according to the European Consensus. The average fibrosis grade differed between each group (P=0.001 or P=0.003). Latent TGF-ß1 values differed significantly between pre-fibrotic (P=0.018) and fibrotic (P=0.031) groups when compared with the control group. The high immunoexpression level of Latent TGF-ß1 in the megakaryocytes from patients with myelofibrosis, which was not observed in patients with essential thrombocythemia, may be associated with the development of bone marrow fibrosis.

Phosphorylation and cytoplasmic localization of MAPK p38 during apoptosis signaling in bone marrow granulocytes of mice irradiated in vivo and the role of amifostine in reducing these effects.

We studied p38 phosphorylation and its intracellular localization during p53 and Puma (a p53 upregulated modulator of apoptosis) apoptotic signaling pathway in bone marrow granulocytes in mice irradiated in vivo and the role of the radioprotector amifostine in ameliorating these responses. Sixty-four C57BL mice were randomly assigned in two non-irradiated (Ami-/rad- and Ami+/rad-) and two irradiated (Ami-/rad+ and Ami+/rad+) groups. Animals received 400mg/kg of amifostine i.p. 30 min prior to a single whole body radiation dose of 7Gy. The experiments were performed using immunohistochemistry for caspase-3, cleaved caspase-3, p53, p-p53 (Ser 15), Puma, p38 and p-p38 (Thr 180/Tyr 182) protein expression. In addition transmission electron microscopy was used for ultrastructural characterization of apoptosis. Data showed that: (i) amifostine significantly reduced the number of apoptotic cells, (ii) p-p53 and Puma proteins were strongly immunostained in granulocytes after irradiation (Ami-/rad+), (iii) amifostine decreased the immunostaining of the proteins (Ami+/rad+), (iv) p38 was immunolocalized in physiological conditions in the nucleus and cytoplasm of granulocytes and neither radiation nor amifostine changed the protein immunostaining or its subcellular distribution, but influenced its activation, (v) radiation-induced p38 phosphorylation and its cytoplasmic accumulation during apoptosis signaling in granulocytes after whole body high radiation dose and amifostine markedly reduced these effects.

Duas classes de mutação na evolução de policitemia vera para leucemia mielóide aguda / Two-hit model of leukemogenesis in the evolution of polycythemia vera to acute myeloid leukemia

Policitemia vera (PV) é doença mieloproliferativa crônica com risco de transformação para mielofibrose ou para leucemia mielóide aguda (LMA) na evolução da doença. Dez a 25 por cento dos pacientes têm anormalidade citogenética ao diagnóstico, chegando a 50 por cento com a progressão. Relatamos caso de PV com transformação para LMA no qual foi possível demonstrar a teoria de duas classes de mutação: uma indutora de proliferação e outra de bloqueio de maturação. Caso: Paciente feminina, 55 anos, PV diagnosticada em 2002, com mutação JAK2V617F, cariótipo normal, tratada com flebotomias e hidroxiureia. Em 2006 houve progressão para mielofibrose pós-policitêmica e novo cariótipo mostrou 46,XX,del(20)(q13.1) em 4/20 metáfases. Análise por FISH para região 20q13 em amostra estocada confirmou a deleção ao diagnóstico. Após um ano houve transformação para LMA. A mutação JAK2V617F é suficiente para causar proliferação de precursores eritropoéticos, sendo o mecanismo fisiopatogênico primário na PV. Entretanto, a evolução da doença é heterogênea, sugerindo a ocorrência de fenômenos adicionais, levando à instabilidade genômica e contribuindo para a leucemogênese. O caso apresentado sustenta o modelo de dois passos na progressão da PV para LMA, no qual uma classe de mutação gênica confere vantagem proliferativa (JAK2V617F) e outra classe bloqueia a diferenciação hematopoética (deleção 20q). Evidenciaram-se nessa paciente dois eventos contribuindo para a proliferação e para o bloqueio de maturação. Outros mecanismos devem estar implicados e estudos prospectivos devem ser encorajados na tentativa de elucidação dos diferentes passos envolvidos na leucemogênese.

Polycythemia vera (PV) is a chronic myeloproliferative disorder that can evolve to marrow fibrosis or acute leukemia (AML). Cytogenetic alterations can be detected in around 25 percent of patients at diagnosis and in up to 50 percent of those with progression. We report a case of PV with evolution to AML in which it was possible to demonstrate the two-hit model of leukemogenesis: one mutation confers proliferative advantage and another interferes with differentiation. Case: A 55-year-old female patient was diagnosed with PV in 2002 and treated with phlebotomies and hydroxyurea. In 2006, there was progression topost-polycythemic fibrosis with AML one year later. She presented the JAK2V617F mutation. The result of karyotyping performed at diagnosis was normal and at transformation, 46,XX,del(20)(q13.1) was detected in 4/20 metaphases. FISH analysis of a stored sample for 20q13 showed the deletion in 20 percent of interphases confirming the earlier presence of a clonal abnormality that was not detected by karyotyping. The JAK2V617F mutation is sufficient to cause proliferation of hematopoietic cells and has been established as a primary pathogenetic mechanism in PV. However, the evolution of the disease is heterogeneous, suggesting the occurrence of additional phenomena contributing to leukemogenesis. This case demonstrates the two-hit model in the progression of PV to LMA, in which a class of mutation induces proliferative advantage and another blocks differentiation. Two events which contribute to proliferation and to maturation blockade were detected in this patient. Other mechanisms may be implicated and prospective studies should be encouraged in an attempt to elucidate the different steps involved in leukemogenesis.

Serum ferritin level remains a reliable marker of bone marrow iron stores evaluated by histomorphometry in hemodialysis patients.

BACKGROUND AND OBJECTIVES: As well as being a marker of body iron stores, serum ferritin (sFerritin) has also been shown to be a marker of inflammation in hemodialysis (HD) patients. The aim of this study was to analyze whether sFerritin is a reliable marker of the iron stores present in bone marrow of HD patients. DESIGN: Histomorphometric analysis of stored transiliac bone biopsies was used to assess iron stores by determining the number of iron-stained cells per square millimeter of bone marrow. RESULTS: In 96 patients, the laboratory parameters were hemoglobin = 11.3 +/- 1.6 g/dl, hematocrit = 34.3 +/- 5%, sFerritin = 609 +/- 305 ng/ml, transferrin saturation = 32.7 +/- 22.5%, and C-reactive protein (CRP) = 0.9 +/- 1.4 mg/dl. sFerritin correlated significantly with CRP, bone marrow iron, and time on HD treatment (P = 0.006, 0.001, and 0.048, respectively). The independent determinants of sFerritin were CRP (beta-coef = 0.26; 95% CI = 24.6 to 132.3) and bone marrow iron (beta-coef = 0.32; 95% CI = 0.54 to 2.09). Bone marrow iron was higher in patients with sFerritin >500 ng/ml than in those with sFerritin < or =500 ng/ml. In the group of patients with sFerritin < or =500 ng/ml, the independent determinant of sFerritin was bone marrow iron (beta-coef = 0.48, 95% CI = 0.48 to 1.78), but in the group of patients with sFerritin >500 ng/ml, no independent determinant of sFerritin was found. CONCLUSIONS: sFerritin adequately reflects iron stores in bone marrow of HD patients.

Amifostine does not prevent activation of TGFbeta1 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.

Comparison of cytogenetics with FISH in 40 myelodysplastic syndrome patients.

Karyotyping is important for diagnosis and prognosis of myelodysplastic syndrome (MDS). Using fluorescence in situ hybridization (FISH) either mitotic or interphase cells can be analyzed and a higher number of cells can be screened. This study evaluated the effectiveness of FISH in detecting the most common chromosomal abnormalities [-5/del 5q/-7/+8/del 11q23 and -Y] in 40 patients with MDS. Karyotype detected abnormalities in 35.2% of the patients and FISH in 35%, while some abnormalities remained undetected by each approach but the association of both methods increased the detection rate up to 40%.

In vivo radioprotection of mouse bone marrow: protection from apoptotic death by WR-2721

Apoptotic cell death is an important phenomenon in radiation bone marrow injury and the compound WR-2721 can protect hematopoietic tissue against such injury. In this study, we assessed the ability of WR-2721 to prevent radiation-induced apoptosis in bone marrow cells. Femoral bone marrow from C57BL male mice was used. The marrow was studied 4 h, 12 h, 24 h and 10 days after a single whole-body radiation dose of 7 Gy. Mice which received WR-2721 (400 mg/kg, i.p.) 30 min before irradiation were compared with unprotected mice. Less injury and a significant reduction in the number of apoptotic cells were observed 4 h (49.6 per cent less) and 12 h (40.8 per cent less) after irradiation in the group that received WR-2721 compared to the unprotected mice. An earlier than expected recovery was also observed 10 days after irradiation in the protected group. This is the first study in vivo to report the protection by WR-2721 of bone marrow cells from apoptosis following exposure to radiation.

Peritoneal infection by Candida albicansL study of number and size limphocytes and phagocitic activity of peritoneal macrophages in mice

The main purpose of this investigation was to study some aspects of leucocytes (granulocytes and limphocytes) and the phagocitic activity of peritoneal macrophages. In this experiment, which took place at Escola Paulista de Medicina - Universidade Federal de SÒo Paulo - Brazil, it was used twenty female C57BLACK mice. Half of them were submitted to radiation to obtain immunossupressed animals (group A - irradiated mice). The other ten mice were not irradiated (Group B - control). The animals were sorted in four subgroups: A-1, A-2, B-1 and B-2. Mice of the groups A-1 and B-1 were injected with saline, and those the subgroups A-2 and B-2, were infected with Candida albicans (ATCC 90029). The resultant data showed significant differences in the number of leucocytes (granulocytes and limphocytes), and in the medium size of limphocytes between irradiated and non irradiated mice. Related to peritoneal macrophages, it was observed that the number of macrophages was lower in irradiated mice and the phagocitic activity was decreased in the irradiated and infected animals.

Alteraçäo da fibrose hepática induzida pelo tetracloreto de carbono, pela administraçäo prévia de vitamina A

A administraçäo prévia de vitamina A a ratos em que a fibrose hepática foi induzida por injeçöes i.p. de tetracloreto de carbono resultou em significativa reduçäo dos valores de colágeno hepático e na fibrose hepática histologicamente avaliada. Os possíveis mecanismos de atuaçäo da vitamina A säo discutidos