In Vitro Activity and Resistance Profile of Dasabuvir,a Nonnucleoside Hepatitis C Virus Polymerase Inhibitor

Dasabuvir (ABT-333) is a nonnucleoside inhibitor of the RNA-dependent RNA polymerase encoded by the hepatitis C virus (HCV) NS5B gene. Dasabuvir inhibited recombinant NS5B polymerases derived from HCV genotype 1a and 1b clinical isolates, with 50% inhibitory concentration (IC₅₀) values between 2.2 and 10.7 nM, and was at least 7,000-fold selective for the inhibition of HCV genotype 1 polymerases over human/mammalian polymerases. In the HCV subgenomic replicon system, dasabuvir inhibited genotype 1a (strain H77) and 1b (strain Con1) replicons with 50% effective concentration (EC₅₀) values of 7.7 and 1.8 nM, respectively, with a 13-fold decrease in inhibitory activity in the presence of 40% human plasma. This level of activity was retained against a panel of chimeric subgenomic replicons that contained HCV NS5B genes from 22 genotype 1 clinical isolates from treatment-naive patients, with EC₅₀s ranging between 0.15 and 8.57 nM. Maintenance of replicon-containing cells in medium containing dasabuvir at concentrations 10-fold or 100-fold greater than the EC₅₀ resulted in selection of resistant replicon clones. Sequencing of the NS5B coding regions from these clones revealed the presence of variants, including C316Y, M414T, Y448C, Y448H, and S556G, that are consistent with binding to the palm I site of HCV polymerase. Consequently, dasabuvir retained full activity against replicons known to confer resistance to other polymerase inhibitors, including the S282T variant in the nucleoside binding site and the M423T, P495A, P495S, and V499A single variants in the thumb domain. The use of dasabuvir in combination with inhibitors targeting HCV NS3/NS4A protease (ABT-450 with ritonavir) and NS5A (ombitasvir) is in development for the treatment of HCV genotype 1 infections.     

Hormone replacement therapy and mortality in 52- to 70-year-old women: the Kuopio Osteoporosis Risk Factor and Prevention Study

OBJECTIVES: To analyze prospectively the association between hormone replacement therapy (HRT) and mortality in women before old age. DESIGN AND METHODS: A group of 11,667 women (91% of the age cohort of the area) aged 52-62 years from the population-based Kuopio Osteoporosis Risk Factor and Prevention Study were followed for 7 years in 1994-2001. Information about HRT use and health events was obtained from two repeated questionnaires in 1989 and 1994. Information about deaths and causes of death from the follow-up period was obtained from the Statistics Finland. Cox's proportional-hazards models were used to calculate risk of death related to the use of HRT. RESULTS: At the start of follow-up, 2203 women had used HRT > 5 years, 3945 women < or = 5 years and 5519 women had never used it. During the follow-up, 361 deaths occurred. Compared with non-users of HRT, the adjusted hazard ratio (HR) of death from any cause was 1.05 (95% confidence interval (CI) 0.80-1.36) in women who used HRT < or = 5 years and 1.06 (95% CI 0.78-1.46) in women who used HRT > 5 years. The adjusted HR for coronary heart disease (CHD) mortality in women who used HRT < or = 5 years was 0.79 (95% CI 0.36-1.73), and in women who used HRT > 5 years, 2.16 (95% CI 0.93-4.98). For breast cancer mortality the adjusted HR for < or = 5 years of HRT use was 0.96 (95% CI 0.32-2.82) and 2.62 (95% CI 0.98-7.00) for > 5 years of HRT use. CONCLUSIONS: History of HRT use does not affect overall or CHD mortality in women. More than 5 years of HRT use may increase the risk of breast cancer mortality.     

Carotid artery intima-media thickness in Finnish families with familial combined hyperlipidemia

BACKGROUND: Familial combined hyperlipidemia (FCHL) is the most common hereditary lipid disorder that predisposes the patients to premature coronary heart disease. Members of FCHL families are categorised as affected or unaffected according to serum lipid levels. This study is aimed to evaluate whether there is a difference in carotid artery wall thickness between asymptomatic FCHL family members who are affected and those who are unaffected according to the currently used lipid criteria. METHODS AND RESULTS: Carotid artery ultrasonography with intima-media thickness (IMT) measurements was performed for 148 members of 39 Finnish FCHL families. Study subjects who had no history of coronary heart disease or stroke were divided into two groups according to their serum total cholesterol and/or triglyceride levels. The average carotid IMT of the affected subjects (0.75+/-0.15 mm) was not significantly different from that of their unaffected relatives (0.73+/-0.13 mm), P=0.90. In multivariate analysis, age, gender, and pulse pressure, but no lipid variables, contributed significantly to the variation of carotid IMT. CONCLUSIONS: The IMT findings in FCHL family members indicate that the current lipid criteria alone are of limited value in predicting long-term risk of cardiovascular disease in asymptomatic members of FCHL families.     

The role of facemasks and hand hygiene in the prevention of influenza transmission in households: results from a cluster randomised trial; Berlin, Germany, 2009-2011

Background

Previous controlled studies on the effect of non-pharmaceutical interventions (NPI) - namely the use of facemasks and intensified hand hygiene - in preventing household transmission of influenza have not produced definitive results. We aimed to investigate efficacy, acceptability, and tolerability of NPI in households with influenza index patients.

Methods

We conducted a cluster randomized controlled trial during the pandemic season 2009/10 and the ensuing influenza season 2010/11. We included households with an influenza positive index case in the absence of further respiratory illness within the preceding 14 days. Study arms were wearing a facemask and practicing intensified hand hygiene (MH group), wearing facemasks only (M group) and none of the two (control group). Main outcome measure was laboratory confirmed influenza infection in a household contact. We used daily questionnaires to examine adherence and tolerability of the interventions.

Results

We recruited 84 households (30 control, 26 M and 28 MH households) with 82, 69 and 67 household contacts, respectively. In 2009/10 all 41 index cases had a influenza A (H1N1) pdm09 infection, in 2010/11 24 had an A (H1N1) pdm09 and 20 had a B infection. The total secondary attack rate was 16% (35/218). In intention-to-treat analysis there was no statistically significant effect of the M and MH interventions on secondary infections. When analysing only households where intervention was implemented within 36 h after symptom onset of the index case, secondary infection in the pooled M and MH groups was significantly lower compared to the control group (adjusted odds ratio 0.16, 95% CI, 0.03-0.92). In a per-protocol analysis odds ratios were significantly reduced among participants of the M group (adjusted odds ratio, 0.30, 95% CI, 0.10-0.94). With the exception of MH index cases in 2010/11 adherence was good for adults and children, contacts and index cases.

Conclusions

Results suggest that household transmission of influenza can be reduced by the use of NPI, such as facemasks and intensified hand hygiene, when implemented early and used diligently. Concerns about acceptability and tolerability of the interventions should not be a reason against their recommendation.

Trial registration

The study was registered with ClinicalTrials.gov (Identifier NCT00833885).     

Up-regulation of a HOXA-PBX3 homeobox-gene signature following down-regulation of miR-181 is associated with adverse prognosis in patients with cytogenetically abnormal AML

Increased expression levels of miR-181 family members have been shown to be associated with favorable outcome in patients with cytogenetically normal acute myeloid leukemia. Here we show that increased expression of miR-181a and miR-181b is also significantly (P < .05; Cox regression) associated with favorable overall survival in cytogenetically abnormal AML (CA-AML) patients. We further show that up-regulation of a gene signature composed of 4 potential miR-181 targets (including HOXA7, HOXA9, HOXA11, and PBX3), associated with down-regulation of miR-181 family members, is an independent predictor of adverse overall survival on multivariable testing in analysis of 183 CA-AML patients. The independent prognostic impact of this 4-homeobox-gene signature was confirmed in a validation set of 271 CA-AML patients. Furthermore, our in vitro and in vivo studies indicated that ectopic expression of miR-181b significantly promoted apoptosis and inhibited viability/proliferation of leukemic cells and delayed leukemogenesis; such effects could be reversed by forced expression of PBX3. Thus, the up-regulation of the 4 homeobox genes resulting from the down-regulation of miR-181 family members probably contribute to the poor prognosis of patients with nonfavorable CA-AML. Restoring expression of miR-181b and/or targeting the HOXA/PBX3 pathways may provide new strategies to improve survival substantially.     

Has Admission Blood Pressure Any Prognostic Value in Patients With Subarachnoid Hemorrhage: An Emergency Department Experience

Hypertension is a well‐known risk factor for the development and rupture of cerebral aneurysms. The authors conducted a study to investigate the prognostic value of admission blood pressure (BP) on prognosis in patients with subarachnoid hemorrhage (SAH). Two hundred patients with SAH were divided into two groups according to Hunt Hess score (good prognosis: 1 to 3, and poor prognosis: 4 and 5) and according to death in hospital (surveyed and died). The prognostic factors of SAH and BP changes according to Hunt Hess scores in the acute stages of the event were evaluated. Admission mean arterial BP values of the patients who died in hospital were significantly lower than in the patients who were surveyed (P=.026). The admission mean arterial BP values were found to be lower in the poor prognostic patients (Hunt Hess score of 4 and 5) (P<.001). Decreased admission BP values were found to be associated with poor prognosis and mortality.     

Congestive Heart Failure and Treatment in Thalassemia Major

The homozygous β-thalassemias are a group of genetically inherited hemoglobin (Hb) disorders characterized by dyserythropoietic anemia. According to the degree of anemia, two main forms, sharing a common basic molecular mechanism, are distinguished: thalassemia major (TM) and thalassemia intermedia (TI). The severity of the clinical phenotype differentiates the two forms. Thalassemia major usually presents as a severe anemia requiring life-long transfusion therapy for survival.

The dramatic improvement in life expectancy of β-thalassemia (thal) patients achieved during the past few decades by virtue of therapeutic advances, has motivated investigators' interest in a better understanding of the clinical consequences of this genetic defect. Heart complications still represent the leading cause of mortality from the disease. The mechanisms of cardiac injury along with its treatment and prevention have attracted the main research efforts in this field. In this review, we present existing knowledge and our personal experience of 30 years of follow-up of over 1,000 thalassemic patients, regarding the basis of the cardiac injury, the clinical findings and the global strategy of the therapeutic intervention in TM patients who develop congestive heart failure (CHF).