Nevirapine Concentration in Hair Samples Is a Strong Predictor of Virologic Suppression in a Prospective Cohort of HIV-Infected Patients

Effective antiretroviral (ARV) therapy depends on adequate drug exposure, yet methods to assess ARV exposure are limited. Concentrations of ARV in hair are the product of steady-state pharmacokinetics factors and longitudinal adherence. We investigated nevirapine (NVP) concentrations in hair as a predictor of treatment response in women receiving ARVs. In participants of the Women’s Interagency HIV Study, who reported NVP use for >1 month from 2003–2008, NVP concentrations in hair were measured via liquid-chromatography-tandem mass-spectrometry. The outcome was virologic suppression (plasma HIV RNA below assay threshold) at the time of hair sampling and the primary predictor was nevirapine concentration categorized into quartiles. We controlled for age, race/ethnicity, pre-treatment HIV RNA, CD4 cell count, and self-reported adherence over the 6-month visit interval (categorized ≤ 74%, 75%–94% or ≥ 95%). We also assessed the relation of NVP concentration with changes in hepatic transaminase levels via multivariate random intercept logistic regression and linear regression analyses. 271 women contributed 1089 person-visits to the analysis (median 3 of semi-annual visits). Viral suppression was least frequent in concentration quartile 1 (86/178 (48.3%)) and increased in higher quartiles (to 158/204 (77.5%) for quartile 4). The odds of viral suppression in the highest concentration quartile were 9.17 times (95% CI 3.2–26, P < 0.0001) those in the lowest. African-American race was associated with lower rates of virologic suppression independent of NVP hair concentration. NVP concentration was not significantly associated with patterns of serum transaminases. Concentration of NVP in hair was a strong independent predictor of virologic suppression in women taking NVP, stronger than self-reported adherence, but did not appear to be strongly predictive of hepatotoxicity.     

Characterization of HTT Inclusion Size,Location, and Timing in the zQ175 Mouse Model of Huntington′s Disease: An In Vivo High-Content Imaging Study

Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Major pathological hallmarks of HD include inclusions of mutant huntingtin (mHTT) protein, loss of neurons predominantly in the caudate nucleus, and atrophy of multiple brain regions. However, the early sequence of histological events that manifest in region- and cell-specific manner has not been well characterized. Here we use a high-content histological approach to precisely monitor changes in HTT expression and characterize deposition dynamics of mHTT protein inclusion bodies in the recently characterized zQ175 knock-in mouse line. We carried out an automated multi-parameter quantitative analysis of individual cortical and striatal cells in tissue slices from mice aged 2–12 months and confirmed biochemical reports of an age-associated increase in mHTT inclusions in this model. We also found distinct regional and subregional dynamics for inclusion number, size and distribution with subcellular resolution. We used viral-mediated suppression of total HTT in the striatum of zQ175 mice as an example of a therapeutically-relevant but heterogeneously transducing strategy to demonstrate successful application of this platform to quantitatively assess target engagement and outcome on a cellular basis.     

Do Foliar,Litter, and Root Nitrogen and Phosphorus Concentrations Reflect Nutrient Limitation in a Lowland Tropical Wet Forest?

Understanding nutrient limitation of net primary productivity (NPP) is critical to predict how plant communities will respond to environmental change. Foliar nutrients, especially nitrogen and phosphorus concentrations ([N] and [P]) and their ratio, have been used widely as indicators of plant nutritional status and have been linked directly to nutrient limitation of NPP. In tropical systems, however, a high number of confounding factors can limit the ability to predict nutrient limitation —as defined mechanistically by NPP responses to fertilization— based on the stoichiometric signal of the plant community. We used a long-term full factorial N and P fertilization experiment in a lowland tropical wet forest in Costa Rica to explore how tissue (foliar, litter and root) [N] and [P] changed with fertilization, how different tree size classes and taxa influenced the community response, and how tissue nutrients related to NPP. Consistent with NPP responses to fertilization, there were no changes in community-wide foliar [N] and [P], two years after fertilization. Nevertheless, litterfall [N] increased with N additions and root [P] increased with P additions. The most common tree species (Pentaclethra macroloba) had 9 % higher mean foliar [N] with NP additions and the most common palm species (Socratea exohrriza) had 15% and 19% higher mean foliar [P] with P and NP additions, respectively. Moreover, N:P ratios were not indicative of NPP responses to fertilization, either at the community or at the taxa level. Our study suggests that in these diverse tropical forests, tissue [N] and [P] are driven by the interaction of multiple factors and are not always indicative of the nutritional status of the plant community.     

GRAF1 promotes ferlin-dependent myoblast fusion

Myoblast fusion (a critical process by which muscles grow) occurs in a multi-step fashion that requires actin and membrane remodeling; but important questions remain regarding the spatial/temporal regulation of and interrelationship between these processes. We recently reported that the Rho-GAP, GRAF1, was particularly abundant in muscles undergoing fusion to form multinucleated fibers and that enforced expression of GRAF1 in cultured myoblasts induced robust fusion by a process that required GAP-dependent actin remodeling and BAR domain-dependent membrane sculpting. Herein we developed a novel line of GRAF1-deficient mice to explore a role for this protein in the formation/maturation of myotubes in vivo. Post-natal muscles from GRAF1-depleted mice exhibited a significant and persistent reduction in cross-sectional area, impaired regenerative capacity and a significant decrease in force production indicative of lack of efficient myoblast fusion. A significant fusion defect was recapitulated in isolated myoblasts depleted of GRAF1 or its closely related family member GRAF2. Mechanistically, we show that GRAF1 and 2 facilitate myoblast fusion, at least in part, by promoting vesicle-mediated translocation of fusogenic ferlin proteins to the plasma membrane.     

Hypofractionated radiotherapy has the potential for second cancer reduction

Background and Purpose  

A model for carcinoma and sarcoma induction was used to study the dependence of carcinogenesis after radiotherapy on fractionation.     

Association of serum markers with improvement in clinical response measures after treatment with golimumab in patients with active rheumatoid arthritis despite receiving methotrexate: results from the GO-FORWARD study

Introduction  

The goal of this study was to identify serum markers that are modulated by treatment with golimumab with or without methotrexate (MTX) and are associated with clinical response.     

The occurrence of chronic disease and other conditions in a large population-based cohort of native Californian twins.

We describe the prevalence of chronic diseases and conditions in a large cohort of twins, which has been developed to facilitate studies of the role of genetics and environment in the development of disease. The California Twin Program (CTP) comprises twins born in California between 1908 and 1982. Birth records from all multiple births (256,616 in total) were linked (multiple times between 1990 and 2001) with the California Department of Motor Vehicles (DMV) roster of licensees to obtain address information. The linkages have revealed 161,109 matches and, because of less complete DMV records in some years, were less successful in older females than in all others. To date over 51,000 of these twins have completed a detailed 16-page mailed risk factor questionnaire. Based on estimates of numbers of individuals receiving a questionnaire, our crude response rates are as high as 63.6% (among females currently in their 50s), with an overall crude response rate of 37.9%. Similar to our previous report regarding the first 42,000 twins, the current group who have completed the questionnaire are representative of the population from which they were drawn (in terms of age, sex, race and residential distribution). Self-reported disease frequencies are provided, along with current estimates of future cancer incidence and mortality rates likely to be observed in the group. We outline our plans for cohort expansion, additional studies using the cohort, and future plans for inviting collaboration.     

Synthesis of linear and comb-like peptide constructs containing up to four copies of a T cell epitope and their capacity to stimulate T cells.

Polypeptide constructs containing up to four copies of the T cell epitope 306-318 of influenza virus haemagglutinin have been synthesized on solid phase. Between the copies, a non-natural PEG-based spacer amino acid has been introduced. The oligomeric epitopes were analysed by RP-HPLC and ES-MS. The arrangement of the epitopes within the peptide constructs was either linear or comb-like. The proliferative response in a T helper cell assay induced by these oligomerized epitopes has been tested, showing that the linearly arranged epitopes are more effective than the comb-like oligomers.