P-glycoprotein (P-gp) has been found expressed in normal human cells, such as bone marrow and peripheral blood cells. The aim of this study was to investigate whether HIV-protease inhibitors ...(HIV-PIs) interact with P-gp efflux function in normal human peripheral blood lymphocytes (PBLs) and CD34 progenitor cells. Moreover, we analyzed the in vivo effect of HIV-PIs on P-gp function in PBLs from HIV-infected patients receiving highly active antiretroviral therapy (HAART). We found that HIV-PIs (i.e., ritonavir, saquinavir, nelfinavir and indinavir) interfere with P-gp function in normal PBLs as demonstrated by the reduced efflux of rhodamine 123 (Rh123). This effect was dose-dependent and suggested the following hierarchyritonavir > saquinavir > nelfinavir > indinavir. We further analyzed the effect of HIV-PIs on the P-gp function in specific PBLs subsets. Our results show an HIV-PI-induced inhibition of P-gp function in CD4 and CD8 T cell subsets, mostly caused by the effect on the naive compartment of both CD4 and CD8 T cells. The same inhibitory effect was found in CD34 hematopoietic progenitor cells. With respect to the in vivo evaluation of P-gp function in PBLs from HIV-infected patients, we found reduced levels of Rh123 efflux that reached the lowest value in AIDS patients receiving HAART. We concluded that HIV-PIs interfere with P-gp function in major cellular targets for HIV infection, such as CD4 T cells and CD34 progenitor cells. This ability may contribute to P-gp efflux function defect found in HIV-infected patients and suggests that drug interaction studies are crucial to an overall understanding of the effects of this important group of drugs.
Institute of Cardiology, Catholic University, Rome, Italy. f.burzotta@eudoramail.com
BACKGROUND AND OBJECTIVES: The prognostic value of the G20210A prothrombin gene polymorphism in patients with a ...first acute coronary syndrome has not been previously assessed. We conducted a prospective study to investigate this issue. DESIGN AND METHODS: Genotyping at the 20210 prothrombin gene locus was performed in 162 patients with a first episode of myocardial infarction (MI) or unstable angina (UA) occurring before 65 years of age. Patients were stratified according to cardiovascular risk factors and to treatment strategy. The subsequent two-year relative risk (RR) of adverse events (death, MI and UA) was adjusted for possible confounders and analyzed according to genotype, risk factor category, and treatment allocation. RESULTS: In the entire study population, the prothrombin variant did not significantly increase the two-year risk of events: the adjusted RR for GA vs GG carriers was 1.82 (95% CI 0.68-4.89). However, in the absence of traditional cardiovascular risk factors the risk of events was consistently higher: among the 46 patients without hypertension, diabetes and hypercholesterolemia, GA vs GG carriership was associated with an adjusted RR at two years of 5.64 (95% CI 1.07-29.84). The gene variant also enhanced the risk of events among the 98 patients who did not undergo myocardial revascularization procedures (RR for GA vs GG: 2.89, 95% CI 1.04-8.00), but not among those who did. INTERPRETATION AND CONCLUSIONS: The present prospective study suggests that heterozygosity for the G20210A prothrombin polymorphism adversely affects prognosis after a first acute coronary syndrome in the subgroup of patients without metabolic risk factors and in those not treated by revascularization procedures.
We describe a case of pure red cell aplasia caused by a B19 parvovirus infection in a female myasthenic patient treated with plasma exchange, corticosteroids, and cholinesterase inhibitors. Two weeks ...after albumin infusion, she developed anemia with an absence of reticulocytes. A bone marrow aspirate was performed, showing a markedly hypoplastic erythroid series with numerous giant pronormoblasts. Anemia with severe reticulocytopenia and morphology of bone marrow suggested a diagnosis of pure erythroblastopenia due to parvovirus B19 infection, which was confirmed by positive immunoglobulin (Ig)M and IgG anti-B19 virus. The patient successfully responded to IVIG treatment with a complete remission. In this case, we could not confirm whether an albumin-derived infection combined with a concomitant immunocompromised condition due to myasthenia and immunosuppressive treatment was responsible for the disease. Although human B19 DNA content does not reflect infectivity, it is not possible to exclude that blood derivates, such as albumin, clot factors, and immune globulin may be infectious. Actually, blood component B19 infection is still an unresolved problem. Many strategies such as new methods for viral inactivation and discarding positive B19 units may help to increase blood product safety.
Hyperhomocysteinemia is an established risk factor for deep vein thrombosis. Factor V Leiden has been reported to potentiate the thrombotic risk related with severe hyperhomocysteinemia, being more ...represented in thrombotic patients with homocystinuria as compared with patients without a history of thrombosis. The results concerning the interaction between moderate hyperhomocysteinemia and inherited thrombophilic factors such as Factor V Leiden or the prothrombin G20210A mutation are contradictory. The relative risk for venous thrombosis has been reported to be increased 10- to 50-fold in patients carrying both hyperhomocysteinemia and inherited thrombophilia in comparison with normal controls, suggesting a synergistic interaction, yet other studies failed to confirm such conclusion. The heterogeneity of these findings is in part due to the small number of individuals with double defects, leading to statistically unreliable results. Genotyping for mutations that are possible causes of moderate hyperhomocysteinemia, such as the thermolabile variant (C677T) of methylenetetrahydrofolate reductase (MTHFR), does not seem useful to identify individuals at higher risk for venous thromboembolism. In fact, in most of the studies the presence of the C677T MTHFR homozygous genotype does not increase the thrombotic risk associated with Factor V Leiden or the prothrombin mutation.
Inherited thrombophilia is associated with thromboembolic events and/or poor obstetric outcome. We evaluated the pregnancy outcome in women with inherited thrombophilia treated with ...low-molecular-weight heparin (LMWH).
38 thrombophilic women with a history of thromboembolic events and/or poor obstetric outcome were treated during their 39 consecutive pregnancies with LMWH from pregnancy verification until 4-6 weeks in puerperium. A fixed dose of enoxaparin 4,000 IU/day (except 1 case who required nadroparin 0.3 ml/day) was administered in most cases, adopting a higher dose (6,000 IU/day to 6,000 IU twice a day) in those with previous thromboembolic events.
In the treated women, all had a good obstetric outcome, whereas in the previous untreated pregnancies (n = 78), the rate of fetal loss (early and late) was 76.9%, only 12 live infants survived (66.6%). Moreover, birth weight resulted significantly higher in live infants born to treated pregnancies in comparison to that of previous untreated pregnancies (p = 0.009). No maternal thrombosis or major bleeding complications were recorded.
The treatment with LMWH improved pregnancy outcome resulting effective and safe in thrombophilic women with a history of thromboembolic events and/or poor obstetric outcome.
Stem/progenitor cells endowed with in vitro and in vivo haematopoietic activity express the surface protein CD34. Transforming growth factor β1 (TGF‐β1) is one of the soluble molecules that regulate ...cell cycle and differentiation of haematopoietic cells, but has pleiotropic activities depending on the state of responsiveness of the target cells. It has previously been shown that TGF‐β1 maintains human CD34+ haematopoietic progenitors in an undifferentiated state, independently of any cell cycle effect. Here, we have shown that TGF‐β1 upregulates the human CD34, an effect that was evident in primary stem/progenitor cells (CD34+lin–) both at the transcriptional and protein levels, and was not associated with any relevant effect on cell growth. The presence of TGF‐β1 influenced differentiation, maintaining primary CD34+/Lin– in an undifferentiated state. This effect was associated with Smad activation and with a dramatic decrease in p38 phosphorylation. Moreover, blocking p38 phosphorylation by the SB202190 inhibitor increased CD34 RNA levels but did not enhance CD34 protein expression in CD34+/Lin– cells, suggesting that modulation of multiple signalling pathways is necessary to reproduce TGF‐β1 effects. These data establish the role that TGF‐β1 has in the modulation of the CD34 stem/progenitor protein and stem/progenitor functions, providing important clues for understanding haematopoietic development and a potential tool for the modulation of human haematopoiesis.
A retrospective study of 76 episodes of candidemia in 73 patients with underlying hematological malignancy, from 1988 until 1997, has been conducted to evaluate the clinical characteristics and to ...ascertain the variables related to the onset and the outcome of candidemia. The most frequent malignancy was acute myeloid leukemia (29 episodes). Candidemia developed mainly during aplasia in patients refractory to chemotherapy (42%). In 65 episodes (86%) the patients were neutropenic (ANC < 1×109/l) before the candidemia diagnosis for a median time of 13 d, and in 53 episodes (70%) at microbiological diagnosis of candidemia ANC was <1×109/l. Candida albicans was the most frequently isolated etiologic agent (31 episodes), but C. non‐albicans species sustained the majority of candidemia. Seventeen candidemias developed during azoles prophylaxis. One month after the diagnosis of candidemia, 26 patients died. In 19 cases, death was attributable to candidemia. The case‐control study demonstrated, at univariate analysis, that the colonization with Candida, spp. (p=0.004), antimycotic prophylaxis (p=0.01), presence of central venous catheter (p=0.01), neutropenia (p=0.002), and the use of glycopeptide (p=0.0001) increased the risk of candidemia. Using multivariate regression analysis only colonization with Candida spp. and the previous therapy with glycopeptide were associated with a significantly increased risk. Acute mortality, expressed by a cumulative probability of survival at 30 d from diagnosis of candidemia, was 0.67 (95% C.I. 0.55–0.77) and was significantly reduced in patients with neutrophils <1×109/l when compared to those with neutrophils > 1×109/l (p at Mantel‐Cox=0.029). Overall cumulative probability of survival at 1 yr was 0.38 (95% C.I. 0.27–0.49) and only the treatment with Amfotericin B significantly reduced the risk of death.
Epigenetic silencing of tumor suppressor (TS) genes is a hallmark in human leukemias, particularly through DNA methylation. Cyclin-dependent kinase inhibitors (CKI) are, among other genes, frequently ...found methylated in their promoter region. This epigenetic modification has been described also in acute lymphoblastic leukemia (ALL). However, the relationship between aberrant DNA methylation and protein expression of TS genes has not yet been extensively evaluated in adult ALL series. The aim of this study was to analyze in primary cells from newly diagnosed adult ALL patients, uniformly treated according to the LAL2000 GIMEMA protocol, the promoter methylation status of p73, p21, p15 and p16, evaluating in addition the p21, p15 and p16 protein expression. The DNA methylation status of promoter regions was investigated, according to cell availability, using a widely accepted method based on bisulfite modification of DNA, followed by methylation-specific PCR assay (MSP). Protein expression was evaluated by Western blot. Normal peripheral blood lymphocytes, as already described, resulted unmethylated for p73, p21, p15 and p16, and did not express the p21, p15 and p16 proteins. In ALL patients, in contrast, only the p21 promoter region was found constantly unmethylated. The p15, p16 and p73 promoter genes were found methylated in 15/37 (40.5%), 8/43 (18.6%) and 9/36 (25%) patients, respectively. Only 2/23 cases (8.6%) resulted simultaneously methylated for p15, p16 and p73. The p21 and p15 protein expression was found in 28/85 (32.9%) and 44/85 cases (51.8%), respectively. The p16 protein, in contrast, was never expressed. The p16 methylation was associated with the T-ALL (P=0.005) phenotype and with higher white blood cell (WBC) counts (P=0.027). Resistance to spontaneous induction of apoptosis was significantly associated with p21 protein expression (P=0.019) and its co-expression with p15 (P=0.049). Achievement of CR was not influenced by gene methylation status, nor by single protein expression. Interestingly, the co-expression of p15 and p21 was associated with failure to induction treatment: only 6/63 (9.5%) patients co-expressing p15 and p21 obtained a CR (P=0.027). Multivariate analysis confirmed the unfavorable role of this protein co-expression (P=0.059) on CR achievement. In contrast, once patients achieved remission, p21 protein expression was associated with a prolonged DFS, as confirmed by multivariate analysis for DFS (P=0.039). In conclusion, p15 and p21 protein expression plays an unfavorable prognostic role in adult ALL patients independently of the p73, p21, p15 and p16 gene promoter methylation status.
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