Association of loss of heterozygosity with cytogenetic abnormalities in acute myeloid leukemia and myelodysplastic syndrome

Deletions on chromosomes 5 and 7 are frequently seen in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). It is assumed that these deletions indicate loss of tumor suppressor genes on these chromosomes and until these tumor suppressor genes are identified, the functional consequences of these deletions and the molecular basis of these myeloid disorders cannot be completely understood. We evaluated loss of heterozygosity (LOH) in 44 patients (18 MDS and 26 AML, diagnosed according to WHO classification criteria) at diagnosis, using a four-microsatellite marker panel: an intragenic marker on the 7th intron of gene IRF-1 of the 5q31.1 region and three markers located inside the 7q31.1 region and correlated the LOH with karyotype abnormalities. The microsatellites chosen corresponded to chromosome regions frequently deleted in MDS/AML. The samples with Q (peak area) less than or equal to 0.50 were indicative of LOH. The percent of informative samples (i.e., heterozygous) for the intragenic microsatellite in gene IRF-1 and in loci D7S486, D7S515 and D7S522 were 66.6, 73.7, 75.5, and 48.8 percent, respectively. Cytogenetic abnormalities by G-banding were found in 36 percent (16/44) of the patients (2 of 18 MDS and 14 of 26 AML patients). We found a significantly positive association of the occurrence of LOH with abnormal karyotype (P < 0.05; chi-square test) and there were cases with LOH but the karyotype was normal (by G-banding). These data indicate that LOH in different microsatellite markers is possibly an event previous to chromosomal abnormalities in these myeloid neoplasias.

Plasmablastic multiple myeloma is associated with increased vascular endothelial growth factor immunoexpression

The biologic basis of the negative prognosis of plasmablastic myeloma is not fully understood. To determine whether histologically aggressive multiple myeloma (MM) is associated with a more angiogenic marrow environment, bone marrow samples from 50 recently diagnosed MM patients were evaluated. Twelve percent (6/50) of patients presented plasmablastic MM, and this feature correlated with moderate/strong intensity of vascular endothelial growth factor staining of plasma cells (P = 0.036). Although plasmablastic MM was not associated with increasing of microvessel density, this new evidence of increased expression of vascular endothelial growth factor on plasmablasts suggests that the adverse prognosis conferred by plasmablastic disease may be due, at least in part, to secretion of this angiogenic cytokine, also suggesting that the subset of MM patients with plasmablastic features may derive particular benefit from antiangiogenic therapies.

Fungal infections in marrow transplant recipients under antifungal prophylaxis with fluconazole

Fungal infection is one of the most important causes of morbidity and mortality in bone marrow transplant (BMT) recipients. The growing incidence of these infections is related to several factors including prolonged granulocytopenia, use of broad-spectrum antibiotics, conditioning regimens, and use of immunosuppression to avoid graft-versus-host disease (GvHD). In the present series, we report five cases of invasive mold infections documented among 64 BMT recipients undergoing fluconazole antifungal prophylaxis: 1) A strain of Scedosporium prolificans was isolated from a skin lesion that developed on day +72 after BMT in a chronic myeloid leukemic patient. 2) Invasive pulmonary aspergillosis (Aspergillus fumigatus) was diagnosed on day +29 in a patient with a long period of hospitalization before being transplanted for severe aplastic anemia. 3) A tumoral lung lesion due to Rhizopus arrhizus (zygomycosis) was observed in a transplanted patient who presented severe chronic GvHD. 4) A tumoral lesion due to Aspergillus spp involving the 7th, 8th and 9th right ribs and local soft tissue was diagnosed in a BMT patient on day +110. 5) A patient with a history of Ph1-positive acute lymphocytic leukemia exhibited a cerebral lesion on day +477 after receiving a BMT during an episode of severe chronic GvHD. At that time, blood and spinal fluid cultures yielded Fusarium sp. Opportunistic infections due to fungi other than Candida spp are becoming a major problem among BMT patients receiving systemic antifungal prophylaxis with fluconazole

Açäo dos raios X corpo total sobre os neutrófilos do sangue periférico em primata Cebus apella (macaco prego) / Effects of whole-body X-radiation on the neutrophils of the peripheral blood of the primate Cebus apella (weeping capuchin)

Amostras de sangue periférico foram obtidas de cinco primatas Cebus apella (macaco prego), antes e após exposiçäo aos raios X corpo inteiro, na dose única de 25,8 mC/kg (100R). Parte das amostras foi utilizada para a contagem global de cariosquizes e o restante para a realizaçäo de extensöes sanguíneas e submetidas à coloraçäo de Wright e aos seguintes métodos citoquímicos: ácido periódico Schiff (PAS) para a identificaçäo de glicogênio, Sudan black B para a detecçäo de fosfolipídios e o-toluidina-água oxigenada para a demonstraçäo da mieloperoxidase. Com o método de Wright foram observadas aos 1, 3 e 6 dias após exposiçäo à radiaçäo, alteraçöes nucleares e citoplasmáticas. Após aplicaçäo dos métodos citoquímicos acima referidos, foram observados, de modo geral, nos mesmos períodos de tempo após irradiaçäo: alteraçäo no padräo de distribuiçäo dos grânulos de glicogênio, grânulos mieloperoxidase positivos e sudanófilos de neutrófilos. No que diz respeito a cariosquizes, constatou-se um aumento dos mesmos após 1 dia, persistindo até o 3§ dia após irradiaçäo. Noventa dias após, näo foi observada nenhuma alteraçäo acima referida

Evaluation of the effect of ionizing radiation of mouse hemocytopoietic tissue by reticulocyte count

The effects of exposure to a single, whole body X-ray dose of 154.8 mC/Kg (600 R) on mouse (Mus musculus) hemocytopoietic tissue were analyzed by means of reticulocyte counts in peripheral blood, evaluating indirectly variations of the erythrocyte sector of bone marrow. The efficiency of the method for the evaluation of this tissue was demonstrated, constituting one more radiobiologic parameter to corroborate those existing already