Surveillance of extended-spectrum beta-lactamases from clinical samples and faecal carriers in Barcelona, Spain.

Objectives: The aim of the present study was to characterize and compare the extended-spectrum beta-lactamase (ESBL)-producing organisms isolated from clinical samples and faecal carriers in 2001 and 2002.

Methods: A total of 5251 Enterobacteriaceae isolated from clinical samples and 1321 stool samples were evaluated for the presence of ESBLs. The stool samples were spread onto plates of MacConkey agar containing 2 mg/L cefotaxime for selection of ESBL-producing strains.

The JAK2(V617F) tyrosine kinase mutation in myelofibrosis with myeloid metaplasia: lineage specificity and clinical correlates.

An association between an activating JAK2 mutation (JAK2(V617F)) and BCR/ABL-negative myeloproliferative disorders was recently reported in multiple simultaneous publications. In the current study, mutation analysis for JAK2(V617F) was performed in peripheral blood mononuclear cells (PBMC) from 157 patients with myelofibrosis with myeloid metaplasia (MMM) including 117 with agnogenic (AMM), 22 with postpolycythaemic (PPMM), and 18 with post-thrombocythaemic (PTMM) myeloid metaplasia. The detection rate for JAK2(V617F) was significantly higher in PPMM (91%; homozygous in 18%) compared with either AMM (45.

Surgical and radiotherapeutic approaches for myelofibrosis with myeloid metaplasia.

Sequestration of circulating immature myeloid progenitors in the chronic myeloproliferative disorder myelofibrosis with myeloid metaplasia (MMM) leads to extramedullary hematopoiesis (EMH), as well as end organ enlargement and dysfunction. When medical therapy is inadequate to control symptomatic myeloproliferation, both surgical resection and/or external beam radiotherapy may provide palliative cytoreduction in specific situations. Therapeutic splenectomy may provide relief of pain, mass effect, an improvement in cytopenias, or even palliation of portal hypertension.

Concomitant neutrophil JAK2 mutation screening and PRV-1 expression analysis in myeloproliferative disorders and secondary polycythaemia.

Polycythaemia vera (PV) is closely associated with both an acquired activating mutation of the JAK2 tyrosine kinase (JAK2(V617F)) in granulocyte-derived DNA and increased granulocyte polycythaemia rubra vera-1 (PRV-1) expression. In order to explore the correlation between these two biological markers and compare their diagnostic utility, mutation analysis for JAK2(V617F) and quantitative measurement of granulocyte PRV-1 expression were performed on the same study sample from 100 participants: 38 with PV, 22 with essential thrombocythaemia (ET), 10 with agnogenic myeloid metaplasia (AMM), 19 with secondary polycythaemia (SP) and 11 healthy volunteers. The respective overall (homozygous) JAK2(V617F) mutational frequencies were 95% (26%), 55% (0%), 30% (0%), 0% and 0%.

PS-341-mediated selective targeting of multiple myeloma cells by synergistic increase in ionizing radiation-induced apoptosis.

Objective: Multiple myeloma remains incurable with current therapy. The proteosome inhibitor, PS-341, has shown objective clinical responses in relapsed refractory myeloma patients. We investigated the potential of enhancing the radiosensitivity of myeloma cells by combining with PS-341; the underlying mechanisms were delineated.

Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis.

Polycythemia vera (PV), essential thrombocythemia (ET), and myeloid metaplasia with myelofibrosis (MMM) are clonal disorders arising from hematopoietic progenitors. An internet-based protocol was used to collect clinical information and biological specimens from patients with these diseases. High-throughput DNA resequencing identified a recurrent somatic missense mutation JAK2V617F in granulocyte DNA samples of 121 of 164 PV patients, of which 41 had homozygous and 80 had heterozygous mutations.

Heat shock protein 90 inhibition sensitizes acute myelogenous leukemia cells to cytarabine.

Previous studies demonstrated that ataxia telangiectasia mutated- and Rad3-related (ATR) kinase and its downstream target checkpoint kinase 1 (Chk1) facilitate survival of cells treated with nucleoside analogs and other replication inhibitors. Recent results also demonstrated that Chk1 is depleted when cells are treated with heat shock protein 90 (Hsp90) inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG). The present study examined the effects of 17-AAG and its major metabolite, 17-aminogeldanamycin (17-AG), on Chk1 levels and cellular responses to cytarabine in human acute myelogenous leukemia (AML) cell lines and clinical isolates.

Overexpression of Rab22a hampers the transport between endosomes and the Golgi apparatus.

The transport and sorting of soluble and membrane-associated macromolecules arriving at endosomal compartments require a complex set of Rab proteins. Rab22a has been localized to the endocytic compartment; however, very little is known about the function of Rab22a and inconsistent results have been reported in studies performed in different cell lines. To characterize the function of Rab22a in endocytic transport, the wild-type protein (Rab22a WT), a hydrolysis-deficient mutant (Rab22a Q64L), and a mutant with reduced affinity for GTP (Rab22a S19N) were expressed in CHO cells.

Long-term analysis of the palliative benefit of 2-chlorodeoxyadenosine for myelofibrosis with myeloid metaplasia.

Objective: Therapeutic splenectomy in myelofibrosis with myeloid metaplasia (MMM) may result in extreme thrombocytosis and leukocytosis and accelerated hepatomegaly. We previously described initial palliative benefit from 2-chlorodeoxyadenosine (2-CdA) in such instances. The purpose of this study is to provide long-term follow-up on the durability of response in the initial cohort and in additional subsequent cases.

Angiogenesis and anti-angiogenic therapy in myelofibrosis with myeloid metaplasia.

Myelofibrosis with myeloid metaplasia (MMM) is a clonal stem cell disorder that is characterized by florid bone marrow stromal reaction including collagen fibrosis, osteosclerosis, and angiogenesis. Almost all patients with MMM display increased bone marrow microvessel density (MVD) and the extent is among the highest in hematological malignancies. This particular information has encouraged the therapeutic use of anti-angiogenic drugs in MMM.

Somatic point mutations in RUNX1/CBFA2/AML1 are common in high-risk myelodysplastic syndrome, but not in myelofibrosis with myeloid metaplasia.

Objective: Acquired somatic point mutations in RUNX1/CBFA2/AML1 have recently been described in a subset of patients with myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). Given the importance of core-binding factor in megakaryocytic differentiation and platelet production, as well as the central role of megakaryocytes in the pathophysiology of myelofibrosis with myeloid metaplasia (MMM), we hypothesised that RUNX1 gene mutations might be common in MMM. In addition, it is unclear whether patients with MDS-associated acquired alpha thalassaemia (ATMDS), a special subgroup with a very high incidence of point mutations in the ATRX gene, have an especially high incidence of RUNX1 mutations.

Bone marrow expression of vascular endothelial growth factor in myelofibrosis with myeloid metaplasia.

The biologic relevance and prognostic impact of angiogenesis is being increasingly recognized in many solid tumors and hematologic malignancies including myelofibrosis with myeloid metaplasia (MMM). Many cytokines including vascular endothelial growth factor (VEGF) have been implicated for neoangiogenesis in MMM. However, the exact humoral basis remains to be elucidated.

Peripheral blood CD34 count in myelofibrosis with myeloid metaplasia: a prospective evaluation of prognostic value in 94 patients.

In a prospective study, peripheral blood (PB) CD34 count, bone marrow histology and other clinical parameters were concurrently evaluated in 94 patients with myelofibrosis with myeloid metaplasia (MMM) and the study cohort followed for a minimum of 3 years. Median PB CD34 count was 0.0547 x 10(9)/l (range 0-5.

Bone marrow angiogenesis and its clinical correlates in myelofibrosis with myeloid metaplasia.

Background And Objectives: Previous retrospective studies have indicated markedly increased bone marrow angiogenesis (BMA) in myelofibrosis with myeloid metaplasia (MMM). This issue is further examined in the current prospective study and clinico-pathological correlates sought.

Design And Methods: This was a prospective single institutional study of 66 patients with bone marrow biopsy-proven MMM who were consecutively accrued.

Leukemic transformation in myelofibrosis with myeloid metaplasia: a single-institution experience with 91 cases.

Among 2333 consecutive patients with myelofibrosis with myeloid metaplasia (MMM) seen at our institution, 91 fulfilled the World Health Organization (WHO) criteria for leukemic transformation (LT). All episodes of LT were myeloid in origin (acute myeloid leukemia [AML]) with all French-American-British (FAB) subtypes represented except M3; the most frequent subtypes were M7 (25.4%), M0 (22.

Myelofibrosis with myeloid metaplasia: new developments in pathogenesis and treatment.

Myeloid metaplasia with myelofibrosis (MMM) is a chronic myeloproliferative disorder (CMPD) characterized by progressive anemia, massive splenomegaly, both hepatosplenic and non-hepatosplenic extramedullary hematopoiesis (EMH), a leukoerythroblastic blood smear, circulating progenitor cells, and marked bone marrow stromal reaction including collagen fibrosis, osteosclerosis and angiogenesis. The overall median survival is 5 years although it might range from 2 to 15 years depending on the presence or absence of clinically defined prognostic factors. Death is often due to leukemic transformation, portal hypertension or infection.

Durable responses to thalidomide-based drug therapy for myelofibrosis with myeloid metaplasia.

Objective: To present the results of a long-term analysis of 2 sequential phase 2 trials of thalidomide (alone or in combination) for palliation of myelofibrosis with myeloid metaplasia (MMM).

Patients And Methods: We analyzed (March 1999 to August 2003) initial and long-term outcomes from 36 patients with symptomatic MMM who had enrolled in either our thalidomide single-agent trial (n=15) or our trial of low-dose thalidomide (50 mg/d) combined with prednisone (n=21).

Results: Among the 36 study patients, 20 (56%) showed some improvement in their clinical course.

Neutrophil PRV-1 expression across the chronic myeloproliferative disorders and in secondary or spurious polycythemia.

Recent studies have demonstrated neutrophil overexpression of the polycythemia rubra vera-1 (PRV-1) gene in polycythemia vera (PV) but not in secondary or spurious polycythemia (SP). To validate as well as expand upon this novel observation, we conducted a prospective study of 88 subjects: 30 with PV, 22 with SP, 14 with essential thrombocythemia (ET), 12 with myelofibrosis with myeloid metaplasia (MMM), and 10 controls. To minimize interstudy methodologic differences, we used a published real-time polymerase chain reaction (PCR)-based assay.

Nonhepatosplenic extramedullary hematopoiesis: associated diseases, pathology, clinical course, and treatment.

Objective: To define associated clinical conditions, pathology, natural history, and treatment outcome of nonhepatosplenic extramedullary hematopoiesis (NHS-EMH).

Patients And Methods: We retrospectively reviewed the medical charts of all patients identified as having NHS-EMH from 1975 to 2002. Diagnosis was made by tissue biopsy, fine-needle aspiration biopsy, or radionuclide bone marrow scanning.