Predictors of high on-clopidogrel platelet reactivity in patients with acute coronary syndrome

High on-clopidogrel platelet reactivity (HPR) is a predictor of ischemic events after percutaneous coronary intervention. We conducted a prospective cohort study to identify variables related to HPR in acute coronary syndrome patients who are at high thrombotic risk. We enrolled 463 patients undergoing urgent coronary angiography. Platelet reactivity was measured 12-36 hours after 600 mg clopidogrel loading with multiple electrode aggregometry (Multiplate® analyzer, Roche, Basel, Switzerland, 6.4 µM ADP). HPR was defined by the consensus cut-off area under the curve >46 U. The rate of HPR was 16.0%. We analyzed simple clinical and laboratory parameters with backward multivariate logistic regression and identified the following predictors of HPR: platelet count (per G/L, OR: 1.0073, 95% CI: 1.0035-1.0112, p = 0.0002), CRP level (per mg/L, OR: 1.0077, 95% CI: 1.0016-1.01372, p = 0.01), and active smoking (OR: 0.51, 95% CI: 0.29-0.89, p = 0.02). We developed and internally validated a risk prediction model demonstrating moderate discriminative capacity (area-under-the-receiver operating characteristic curve = 0.67). In conclusion, we found a relatively low rate of high on-clopidogrel platelet reactivity (16.0%) even in an acute patient cohort. HPR measured by Multiplate was associated with high platelet count and CRP level on admission and was inversely related to active smoking. The model with rapidly available simple parameters might help to identify individuals at risk for HPR in the acute setting.

Simultaneous plasma and genital pharmacokinetics and pharmacodynamics of atazanavir and efavirenz in HIV-infected women starting therapy

Few studies have characterized longitudinal female plasma and genital antiretroviral pharmacokinetics and pharmacodynamics. Among 20 regimen-naive HIV-infected adult women initiating atazanavir-based therapy (n = 9) or efavirenz-based therapy (n = 11), we measured blood CD4+ T lymphocytes, and paired plasma and genital HIV RNA and atazanavir or efavirenz 2 days before starting therapy and 2, 4, 7, 10, 21, 28, 60, 120, and 180 days after. The mean (range) log10 baseline plasma viral load was 4.89 copies/mL (2.64-6.09 copies/mL), and genital was3.30 (1.60-5.00). In the atazanavir and efavirenz groups, mean (SD) days to a 50% decrease in plasma viral load was 8.2 (4.9) versus 9.3 (7.4), P = .7, and in the genital tract it was 7.3 (3.5) versus 9.3 (7.7), P = .5. The median (interquartile range) plasma:genital concentration ratio for atazanavir was 0.11 (0.001-0.46) versus 0.34 (0.05-1.30) for efavirenz, P = .5. Average plasma efavirenz or atazanavir concentrations over time did not affect virologic response. Blood CD4+ percentages increased by +2.3 (P = .06) and +3.0 (P = .003) for every 1 mg/L increase in average plasma and genital drug concentration, respectively. Plasma and genital viral pharmacodynamics were similar between the groups and independent of average concentrations, but blood CD4+ response was related in particular to genital extravascular drug concentrations.

Clinical pregnancy following pre-implantation genetic diagnosis for cystic fibrosis

Pre-implantation genetic diagnosis (PGD) is an established alternative to prenatal testing for couples at risk of transmitting genetic disorders such as cystic fibrosis (CF).PGD screens pre-implantation embryos, allowing the safe transfer of those identified as unaffected. Awareness of CF carrier status in Ireland is increasing following the introduction of neonatal screening in 2011. PGD is the most acceptable reproductive strategy for many at risk Irish couples but until now the treatment necessitated travelling abroad. In 2012, the Irish Medicines Board licenced two Irish fertility clinics to carry out embryo biopsy for PGD. This is the first reported clinical pregnancy following PGD carried out in Ireland.

Alteration of select gene expression patterns in individuals infected with HIV-1

Multiple human proteins have been shown to both support and restrict viral replication, and confirmation of virus-associated changes in the expression of these genes is relevant for future therapeutic efforts. In this study a well-characterized panel of 49 individuals either infected with HIV-1 or uninfected was compiled and analyzed for the effect of HIV infection status, viral load, and antiretroviral treatment on specific gene expression. mRNA was extracted and reverse transcribed from purified CD4+ cells, and quantitative real-time PCR was utilized to scrutinize differences in the expression of four host genes that have been demonstrated to either stimulate (HSP90 and LEDGF/p75) or restrict (p21/WAF1 and APOBEC3G) proviral integration. HIV infection status was associated with slight to moderate alterations in the expression of all four genes. After adjusting for age, mRNA expression levels of HSP90, LEDGF/p75 and APOBEC3G were found to all be decreased in infected patients compared to healthy controls by 1.43-, 1.26-, and 4.71-fold, respectively, while p21/WAF1 expression was increased 2.35-fold. Furthermore, individuals receiving raltegravir exhibited a 1.28-fold reduction in LEDGF/p75 compared to those on non-raltegravir antiretroviral treatment. Identification of these and similar HIV-induced changes in gene expression may be valuable for delineating the extent of host cell molecular mechanisms stimulating viral replication.