Astrocytes and Microglia Respond to Estrogen with Increased apoE mRNAin Vivoandin Vitro

This study examined the regulation of apolipoprotein E (apoE) by 17β-estradiol (E2) in brain glia, using rats with regular ovulatory cycles as anin vivomodel and cultured astrocytes and mixed glia asin vitromodels. Two brain regions were examined which had demonstrated transient synaptic remodeling during the estrous cycle. In the hippocampal CA1 region and the hypothalamic arcuate nucleus, apoE mRNA was elevated at proestrus when plasma E2 was high and synaptic density was increasing. Both astrocytes and microglia contributed to this increase in apoE mRNA.In vitro,E2 treatment had no effect on apoE mRNA levels in monotypic cultures of either astrocytes or microglia. In contrast, mixed glial cultures responded to E2 with increased apoE mRNA and protein, suggesting that heterotypic cellular interactions are important in the brain response to estrogens.In situhybridization in combination with cell-specific markers showed that E2 increased apoE mRNA levels in both astrocytes and microglia. These results, which are the first evidence of apoE mRNA localization to microgliain vivoand the control of apoE expression in brain cells by estrogens, are discussed in terms of the possible protective role of E2 in Alzheimer's disease and prior findings that emphasize the expression of apoE mRNA in astrocytes within the brain.     

Phase I clinical and pharmacology study of clofarabine in patients with solid and hematologic cancers.

Purpose: To define the maximum-tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of clofarabine, given as a 1-hour infusion daily for 5 days, in patients with solid tumors and with acute leukemia. Patients and Methods: The initial part of the study defined the MTD and DLT in solid tumors. The second part of the study defined the MTD and DLT in acute leukemia. Results: The starting dose of clofarabine (15 mg/m(2)) was myelosuppressive, requiring several dose de-escalations to 2 mg/m(2), the dose suggested for phase II studies in solid tumors. Dose escalation in acute leukemia started at 7.5 mg/m(2), with several escalations to 55 mg/m(2). The DLT was reversible hepatotoxicity at 55 mg/m(2). The recommended dose for acute leukemia phase II studies was 40 mg/m(2). Among 32 treated patients with acute leukemia, two achieved a complete response and three had a marrow complete response without platelet recovery (hematologic improvement), for an overall response rate of 16%. At 40 mg/m(2), the median plasma clofarabine level was 1.5 micro mol/L (range, 0.42 to 3.2 micro mol/L; n = 7). Cellular and plasma pharmacokinetic studies suggested dose proportionality but showed a wide variation in intracellular concentrations of clofarabine triphosphate. Conclusion: This phase I study defined the following two MTDs for clofarabine given as a 1-hour infusion daily for 5 days: 2 mg/m(2) for solid tumors, the DLT being myelosuppression; and 40 mg/m(2) for acute leukemia, the DLT being hepatotoxicity. Encouraging activity was observed in acute leukemia.     

A whole blood assay for platelet HPA1 (PLA1) phenotyping applicable to large-scale screening

Any future programme of antenatal screening of pregnancies for risk of neonatal alloimmune thrombocytopenia will have as a major requirement the availability of cost-effective assays which can be applied to large numbers of samples. To address this, we developed a competitive ELISA to type whole blood samples for the platelet alloantigen HPA1a, based on the use of purified glycoprotein (GP) IIb/IIIa from donors of known HPA1 genotype along with well characterized anti-HPA1a antiserum. Microtitre plates were coated with purified GPIIb/IIIa from donors of genotype HPA1a1a/3a3a. Anticoagulated whole blood of unknown HPA1 type was added to each well followed by anti-HPA1a. Residual antiHPA1a antibody not bound to the platelets in the test blood sample, bound to the immobilized HPA1a on the plate and was quantitated by standard ELISA. 475 blood donors were typed by the assay and the results compared in a blinded comparison with typing in the Capture-P^tm assay. Concordance was 100% (468 HPA1a positive and seven HPA1a negative). The HPA1 type of control samples stored as whole blood could be discriminated by this assay for up to 23 d of storage at 4°C. This assay should be suitable for use in large-scale population screening programmes.     

Clinical Significance of Bone Marrow Blast Percentage in Patients With Myelofibrosis and the Effect of Ruxolitinib Therapy

BackgroundThe effect of bone marrow (BM) blasts on the outcome of patients with myelofibrosis (MF) is poorly understood, unless they are ≥ 10% and represent a more aggressive accelerated phase. Similarly, the role of the JAK inhibitor, ruxolitinib (RUX), has not been assessed in correlation with BM blasts.Patients and MethodsHerein, we present clinical characteristics and outcomes of 1412 patients with MF stratified by BM blasts and therapy.ResultsSeven percent and 4% of patients had 5% to 9% and ≥ 10% BM blasts, respectively. Forty-four percent of patients were treated with RUX throughout their disease course. Overall survival (OS) differed among patients with 0% to 1%, 2% to 4%, and 5% to 9% BM blasts, with median OS of 64, 48, and 22 months, respectively (P < .001). Patients with 5% to 9% BM blasts had similar OS as patients with ≥ 10% BM blasts (22 vs. 14 months; P = .73). All patients with < 10% blasts who were treated with RUX showed superior OS to patients who did not receive RUX.ConclusionsOur results indicate that patients with MF with ≥ 5% BM blasts represent a high-risk group with adverse clinical characteristics and inferior outcome. However, they still appear to derive substantial survival benefit from therapy with RUX.