Candida albicans repetitive elements display epigenetic diversity and plasticity

Transcriptionally silent heterochromatin is associated with repetitive DNA. It is poorly understood whether and how heterochromatin differs between different organisms and whether its structure can be remodelled in response to environmental signals. Here, we address this question by analysing the chromatin state associated with DNA repeats in the human fungal pathogen Candida albicans. Our analyses indicate that, contrary to model systems, each type of repetitive element is assembled into a distinct chromatin state. Classical Sir2-dependent hypoacetylated and hypomethylated chromatin is associated with the rDNA locus while telomeric regions are assembled into a weak heterochromatin that is only mildly hypoacetylated and hypomethylated. Major Repeat Sequences, a class of tandem repeats, are assembled into an intermediate chromatin state bearing features of both euchromatin and heterochromatin. Marker gene silencing assays and genome-wide RNA sequencing reveals that C. albicans heterochromatin represses expression of repeat-associated coding and non-coding RNAs. We find that telomeric heterochromatin is dynamic and remodelled upon an environmental change. Weak heterochromatin is associated with telomeres at 30?°C, while robust heterochromatin is assembled over these regions at 39?°C, a temperature mimicking moderate fever in the host. Thus in C. albicans, differential chromatin states controls gene expression and epigenetic plasticity is linked to adaptation

Potent Inhibition of HIV-1 Replication by a Tat Mutant

Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection

Characterization of highly stable liposomal and immunoliposomal formulations of vincristine and vinblastine

Liposome and immunoliposome formulations of two vinca alkaloids, vincristine and vinblastine, were prepared using intraliposomal triethylammonium sucroseoctasulfate and examined for their ability to stabilize the drug for targeted drug delivery in vivo. The pharmacokinetics of both the encapsulated drug (vincristine or vinblastine) and liposomal carrier were examined in Sprague Dawley rats, and the in vivo drug release rates determined. Anti-HER2 immunoliposomal vincristine was prepared from a human anti-HER2/neu scFv and studied for targeted cytotoxic activity in cell culture, and antitumor efficacy in vivo. Nanoliposome formulations of vincristine and vinblastine demonstrated similar pharmacokinetic profiles for the liposomal carrier, but increased clearance for liposome encapsulated vinblastine (t 1/2 = 9.7 h) relative to vincristine (t 1/2 = 18.5 h). Immunoliposome formulations of vincristine targeted to HER2 using an anti-HER2 scFv antibody fragment displayed a marked enhancement in cytotoxicity when compared to non-targeted liposomal vincristine control; 63- or 253-fold for BT474 and SKBR3 breast cancer cells, respectively. Target-specific activity was also demonstrated in HER2-overexpressing human tumor xenografts, where the HER2-targeted formulation was significantly more efficacious than either free vincristine or non-targeted liposomal vincristine. These results demonstrate that active targeting of solid tumors with liposomal formulations of vincristine is possible when the resulting immunoliposomes are sufficiently stabilized

Definitions and methods of measuring and reporting on injurious falls in randomised controlled fall prevention trials: a systematic review

<p>Abstract</p> <p>Background</p> <p>The standardisation of the assessment methodology and case definition represents a major precondition for the comparison of study results and the conduction of meta-analyses. International guidelines provide recommendations for the standardisation of falls methodology; however, injurious falls have not been targeted. The aim of the present article was to review systematically the range of case definitions and methods used to measure and report on injurious falls in randomised controlled trials (RCTs) on fall prevention.</p> <p>Methods</p> <p>An electronic literature search of selected comprehensive databases was performed to identify injurious falls definitions in published trials. Inclusion criteria were: RCTs on falls prevention published in English, study population ≥ 65 years, definition of injurious falls as a study endpoint by using the terms "injuries" and "falls".</p> <p>Results</p> <p>The search yielded 2089 articles, 2048 were excluded according to defined inclusion criteria. Forty-one articles were included. The systematic analysis of the methodology applied in RCTs disclosed substantial variations in the definition and methods used to measure and document injurious falls. The limited standardisation hampered comparability of study results. Our results also highlight that studies which used a similar, standardised definition of injurious falls showed comparable outcomes.</p> <p>Conclusions</p> <p>No standard for defining, measuring, and documenting injurious falls could be identified among published RCTs. A standardised injurious falls definition enhances the comparability of study results as demonstrated by a subgroup of RCTs used a similar definition. Recommendations for standardising the methodology are given in the present review.</p

Trends and connections across the Antarctic cryosphere

Satellite observations have transformed our understanding of the Antarctic cryosphere. The continent holds the vast majority of Earth’s fresh water, and blankets swathes of the Southern Hemisphere in ice. Reductions in the thickness and extent of floating ice shelves have disturbed inland ice, triggering retreat, acceleration and drawdown of marine-terminating glaciers. The waxing and waning of Antarctic sea ice is one of Earth’s greatest seasonal habitat changes, and although the maximum extent of the sea ice has increased modestly since the 1970s, inter-annual variability is high, and there is evidence of longer-term decline in its extent

Health status rated with the Medical Outcomes Study 36-Item Short-Form Health Survey after spinal cord injury.

OBJECTIVE: To describe the health status of Australians with spinal cord injury (SCI). DESIGN: Survey. SETTING: Australian population-based sample. PARTICIPANTS: Participants (N=305) with SCI at recruitment to a randomized trial. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) health questionnaire. RESULTS: Compared with the general population, our sample reported significantly lower scores in 6 SF-36 domains (physical function, role-physical, bodily pain, general health, social function, vitality) and the physical component summary (PCS) score, but unexpectedly higher mental component summary (MCS) scores (difference in mean MCS scores, 4.6; 95% confidence interval [CI], 2.4-6.8). Compared with people with tetraplegia, those with paraplegia had better physical function and PCS scores (difference, 21; 95% CI, 17-24; difference, 3; 95% CI, 1-5, respectively), and worse bodily pain scores (difference, 9; 95% CI, 2-15). Recent urinary infections were associated with worse general health, vitality, mental health, and MCS scores. Receiving family or external physical care was associated with worse physical function and PCS scores, but better mental health and MCS scores. Older age at injury was associated with lower bodily pain and PCS scores. CONCLUSIONS: Using the SF-36, Australians with SCI rate their physical (not mental) health status as worse than the general population

The SF-36 walk-wheel: a simple modification of the SF-36 physical domain improves its responsiveness for measuring health status change in spinal cord injury.

OBJECTIVE: To evaluate the validity and responsiveness of a modified SF-36 within a spinal cord-injured (SCI) population. STUDY DESIGN: SF-36 scores collected at baseline and on completion of a randomized controlled trial in 305 patients with SCI and neuropathic bladder. SETTING: New South Wales, Australia. METHODS: Subjects were administered the standard SF-36 plus three additional questions, in which 'walk' was replaced with 'wheel' for three of the physical function (PF) questions. Discriminant validity was determined by comparing participants with paraplegia and tetraplegia using the effect size (ES). Responsiveness was assessed in the subset of patients who developed a urinary tract infection (UTI) during the trial using the standardized response mean (SRM). RESULTS: Compared with the standard SF-36, the SF-36 walk-wheel modification (SF-36ww) increased the mean PF score from 18 to 39 (P<0.001) and the physical composite score from 33 to 37 (P<0.001). Discriminant validity was similar for both versions (PF paraplegia/tetraplegia: ES 1.09(SF-36) vs 1.08(SF-36ww), n=305). Among 138 SCI patients who developed a UTI, the SF-36ww almost doubled PF responsiveness for all neurological levels (SRM increased from 0.36 to 0.68), more so in tetraplegic (SRM, 0.11 vs 0.58; n=77) than paraplegic groups (SRM, 0.77 vs 0.86; n=61). CONCLUSION: The SF-36ww is a simple, pragmatic modification of the SF-36 PF items, which addresses some problems of content validity and floor effect for SCI subjects and greatly improves responsiveness, particularly for those with tetraplegia. Because it comprises a simple addition to the standard SF-36, external comparisons are preserved