Platelet VASP phosphorylation assessment in clopidogrel-treated patients: Lack of agreement between Western blot and flow cytometry

Vasodilator-stimulated phosphoprotein (VASP) 239 phosphorylation flow cytometric assessment has been reported as a tool to evaluate the responsiveness to clopidogrel in coronary heart disease (CHD) patients. We report for the first time the comparison between flow cytometry and two challenger assays, aggregometry and Western blot. We studied 21 clopidogrel-treated CHD patients, and 28 healthy volunteers. Aggregometry showed platelet function inhibition in patients. VASP 239 phosphorylation was assessed using flow cytometry and Western blot. ADP receptor response index (RI) were calculated using the formula (PGE1) – (PGE1?+?ADP)/(PGE1)?×?100. Flow cytometry was not able to detect clopidogrel intake, as RI were 99?±?10% [68–130] in healthy volunteers, and 91?±?17% [66–127] in treated patients (ns). On the contrary, RI mean in Western blot was 91?±?8% [76–127] in healthy volunteers, and 37?±?25% [4–80] in patients (p<0.05). The extreme values in Western blot revealed inter-individual variability in response to treatment. The comparison between both tests showed a total lack of agreement. Flow cytometric VASP 239 phosphorylation assay lacks sensitivity to detect clopidogrel intake, contrary to Western blot and aggregometry. Caution is required before classifying patients as ‘low-responders’ to thienopyridines using such method.     

New cooperation between doctors and hospital personnel at the Assistance publique-Hopitaux de Paris

Article 51 of the "Hospital, patients, health and territories" law and its implementing provisions emphasise the local nature of cooperation protocols which concern named healthcare professionals. This measure raises a certain number of questions in healthcare institutions. The Paris hospitals authority, Assistance publique-H?pitaux de Paris, has initiated a think tank to consider the issue at an institutional level.     

Four new carvotanacetone derivatives from Sphaeranthus ukambensis, inhibitors of the ubiquitin-proteasome pathway

Six carvotanacetone derivatives (1- 6), amongst which four new compounds (1- 4), were isolated from the aerial parts of Sphaeranthus ukambensis Vatke & O. Hoffm. The structures of the molecules were elucidated by complementary spectroscopic methods, and their biological properties were investigated using human DLD-1 colon cancer cells engineered to stably express a 4?ubiquitin-luciferase (4?Ub-Luc) reporter protein. Five of the isolated carvotanacetone derivatives (2- 6) were found to inhibit the proliferation of the colon cancer cells and interfere with the ubiquitin-proteasome pathway, with potencies in a micromolar range.     

组蛋白去甲基化酶家族中组蛋白去甲基化酶4作用机制及其应用的研究进展

组蛋白甲基化是一种重要的表观遗传性修饰方式,是一个可逆的动态调节过程。组蛋白去甲基化酶家族中组蛋白去甲基化酶4能催化去除组蛋白赖氨酸残基甲基标记,调节染色质的结构,参与精细调控基因转录,维持染色质的活性和非活性平衡。组蛋白去甲基化酶4异常可能导致细胞增殖、分化、个体发育、能量代谢及肿瘤发生发展等多种生物进程异常。研究显示组蛋白去甲基化酶4可作为新的药物靶标。本文就组蛋白去甲基化酶4家族的结构、作用机制、在疾病发生发展进程中的生物学功能及特异性抑制剂开发的最新研究进展作一综述。     

Evaluation of pharmacokinetic interactions after oral administration of mycophenolate mofetil and valaciclovir or aciclovir to healthy subjects

OBJECTIVE: To investigate a potential pharmacokinetic interaction between mycophenolate mofetil (MMF) and aciclovir or valaciclovir.STUDY DESIGN AND PARTICIPANTS: Fifteen healthy subjects were enrolled in a prospective, randomised, open-label, single-dose, cross-over study conducted at a single centre. Subjects received each of the following five oral treatments: (i) aciclovir 800 mg alone; (ii) valaciclovir 2 g alone; (iii) MMF 1 g alone; (iv) valaciclovir 2 g + MMF 1 g; and (v) aciclovir 800 mg + MMF 1 g. The following pharmacokinetic parameters were estimated for aciclovir, mycophenolic acid (MPA) and its inactive glucuronide metabolite (MPAG) from the plasma concentration-time data using noncompartmental methods: area under the concentration-time curve from zero to infinity (AUC infinity), terminal elimination half-life (t1/2z), peak concentration (Cmax) and time to Cmax (tmax). The renal clearance (CLR) of aciclovir was also calculated. These parameters were compared when aciclovir or valaciclovir were coadministered with MMF relative to aciclovir, valaciclovir or MMF given alone.RESULTS AND DISCUSSION: Aciclovir Cmax, tmax and AUC infinity were significantly increased by 40%, 0.38 hour and 31%, respectively, following coadministration of aciclovir and MMF, whereas aciclovir t1/2z was significantly decreased by 11%. Following coadministration of valaciclovir and MMF, aciclovir pharmacokinetic parameters were not significantly modified except for tmax (about 0.5 hour shorter with MMF). MPA and MPAG pharmacokinetic parameters were not significantly modified following coadministration of MMF with valaciclovir or aciclovir except for MPAG AUC infinity, which was decreased by 12% with valaciclovir. Our results are similar to those reported in the literature, except for MPAG AUC. In urine, following coadministration of aciclovir and MMF, aciclovir CLR was significantly decreased by 19%. Competition between MPAG and aciclovir for renal tubular secretion could partly explain this phenomenon. Following coadministration of valaciclovir and MMF, aciclovir CLR was not significantly modified.CONCLUSION: In healthy subjects, interactions are observed after coadministration of MMF and aciclovir, but the extent of the interactions is unlikely to be of clinical significance. These interactions should be investigated in patients with abnormal renal function.     

Haemophilus influenzae carriage in children attending French day care centers: a molecular epidemiological study

The nasopharyngeal Haemophilus influenzae flora of healthy children under the age of 3 years attending day care centers in three distinct French geographic areas was analyzed by sampling during two periods, spring 1999 (May and June) and fall 1999 (November and December). The average carrier rate among 1,683 children was 40.9%. The prevalence of capsulated H. influenzae carriers was 0.4% for type f and 0.6% for type e. No type b strains were found among these children, of whom 98.5% had received one or more doses of anti-Haemophilus b vaccine. Among the strains, 44.5% were TEM-type beta-lactamase producers and nine (1.3%) were beta-lactamase-negative ampicillin-resistant strains. Pulsed-field gel electrophoresis restriction patterns showed a large diversity with 366 SmaI patterns from 663 strains. Among the strains isolated during a given period, 33% were isolated simultaneously in more than one area. In each area, depending on the sampling period, 68 to 72% of the strains had new pulsotypes and persistence of 28 to 32% of the strains was noted. For the 297 beta-lactamase-producing strains, 194 patterns were found. The genomic diversity of these strains was comparable to that of the whole set of strains and does not suggest a clonal diffusion. Among the beta-lactamase-producing strains isolated in November and December, depending on the area, 66 to 73% had new pulsotypes with persistence of only 27 to 33% of the strains. In any given geographic area, colonization by H. influenzae appears to be a dynamic process involving a high degree of genomic heterogeneity among the noncapsulated colonizing strains.     

Therapeutic effects of D-aspartic acid β-hydroxamate (DAH) on friend erythroleukemia

D-aspartic acid β-hydroxamate (DAH), an aspartic acid analogue, exerts anti-tumoral activity against murine leukemia L5178Y bath in vitro and in vivo. We show here that DAH displays activity against Friend leukemia cells (FIX) in vitro: a concentration of 2 mM results in a total inhibition of cell growth. DAH is also active in vivo against Friend virus (FV-P)-induced erythroleukemia. Treatment with DAH, given for 95 days as a single daily i.p. injection to DBA/2 mice 3 days following FV-P inoculation, induced a marked increase of 212% in the mean survival time (MST) of treated animals. Since FV-P-induced erythroleukemia is characterized by the proliferation of mature erythroid precursors, we examined the effect of DAH treatment on erythroid colony-forming cells (CFU-E) and observed that the number of CFU-E per spleen was 30 times lower in DAH treated mice than in the controls. To gain further insight into the early effects of DAH treatment on the early phase of Friend disease, we examined the effects of short DAH treatment on spleen size, hematocrit and viremia in FV-P-infected mice. DAH treatment initiated 3 days post infection (p.i.) inhibited splenomegaly, prevented virus-induced polycythemia, and reduced serum viremia. Late DAH treatment (18 days p.i.) induced regression of FVP-induced disease as evidenced by reduction of spleen weight.