SB-224289 Antagonizes the Antifungal Mechanism of the Marine Depsipeptide Papuamide A

In order to expand the repertoire of antifungal compounds a novel, high-throughput phenotypic drug screen targeting fungal phosphatidylserine (PS) synthase (Cho1p) was developed based on antagonism of the toxin papuamide A (Pap-A). Pap-A is a cyclic depsipeptide that binds to PS in the membrane of wild-type Candida albicans, and permeabilizes its plasma membrane, ultimately causing cell death. Organisms with a homozygous deletion of the CHO1 gene (cho1ΔΔ) do not produce PS and are able to survive in the presence of Pap-A. Using this phenotype (i.e. resistance to Pap-A) as an indicator of Cho1p inhibition, we screened over 5,600 small molecules for Pap-A resistance and identified SB-224289 as a positive hit. SB-224289, previously reported as a selective human 5-HT1B receptor antagonist, also confers resistance to the similar toxin theopapuamide (TPap-A), but not to other cytotoxic depsipeptides tested. Structurally similar molecules and truncated variants of SB-224289 do not confer resistance to Pap-A, suggesting that the toxin-blocking ability of SB-224289 is very specific. Further biochemical characterization revealed that SB-224289 does not inhibit Cho1p, indicating that Pap-A resistance is conferred by another undetermined mechanism. Although the mode of resistance is unclear, interaction between SB-224289 and Pap-A or TPap-A suggests this screening assay could be adapted for discovering other compounds which could antagonize the effects of other environmentally- or medically-relevant depsipeptide toxins

A deep X-ray observation of NGC 4258 and its surrounding field

We present a deep X-ray observation of the low-luminosity active galactic nucleus in NGC4258 (M106) using ASCA. The soft X-ray spectrum <2keV is dominated by thermal emission from optically-thin plasma with kT~0.5keV. The hard X-ray emission is clearly due to a power-law component with photon index Gamma=1.8 absorbed by a column density of N_H=8x10^22/cm^2. The power-law is readily identified with primary X-ray emission from the AGN central engine. We also clearly detect a narrow iron K-alpha emission line at 6.4keV. No broad component is detected. We suggest that the bulk of this narrow line comes from the accretion disk and, furthermore, that the power-law X-ray source which excites this line emission (which is typically identified with a disk corona) must be at least 100GM/c^2 in extent. This is in stark contrast to many higher-luminosity Seyfert galaxies which display a broad iron line indicating a small 10 GM/c^2 X-ray emitting region. It must be stressed that this study constrains the size of the X-ray emitting corona rather than the presence/absence of a radiatively efficient accretion disk in the innermost regions. If, instead, a substantial fraction of the observed narrow line originates from material not associated with the accretion disk, limits can be placed on the parameter space of possible allowed relativistically broad iron lines. By comparing our data with previous ASCA observations, we find marginal evidence for a change in absorbing column density through to the central engine, and good evidence for a change in the AGN flux.Comment: 11 pages, 9 postscript figures. Accepted for publication in Ap

Comparison of ALitretinoin with PUVA as the first-line treatment in patients with severe chronic HAnd eczema (ALPHA):study protocol for a randomised controlled trial

Introduction Hand eczema (HE) is one of the most common skin disorders and an important cause for morbidity and occupational disability. The 1-year prevalence of HE is estimated to be up to 10% and it is estimated that 5%–7% of those develop severe chronic HE. However, current clinical evidence is not compelling enough to guide clinical practice. In a survey among 194 UK dermatologists the most frequent first choice approaches were psoralen combined with ultraviolet A (UVA) treatment (PUVA), oral steroids and alitretinoin (AL). When asked which strategy was most efficient for long-term outcome 20% of clinicians indicated they did not know; 43% of clinicians reported AL and 30% reported PUVA. Methods and analysis ALPHA is a multicentre, open, prospective, two-arm parallel group, randomised controlled trial comparing PUVA and AL with a planned sample size re-estimation. Between 500 and 780 participants will be randomised on a 1:1 basis. The physician’s global assessment (PGA) will direct treatment after randomisation, non-responders will be treated according to usual clinical practice; providing valuable pilot data on second line therapeutic approaches to inform future trials. Assessments will be conducted up to 52 weeks post randomisation. The primary outcome measure is the Hand Eczema Severity Index at 12 weeks. Secondary outcome measures include modified Total Lesion Symptom Score, PGA, time to relapse, patient reported outcome measures and DNA extraction and assessment of genetic variants. A substudy on molecular inflammatory mediators will provide information on subgroup specific treatment responses. Photographs will be taken and HE severity assessed by a central review panel

The effects of moderate alcohol supplementation on estrone sulfate and DHEAS in postmenopausal women in a controlled feeding study

BACKGROUND: We have demonstrated that moderate alcohol consumption (15 g/d, 30 g/d) for 8 weeks resulted in significantly increased levels of serum estrone sulfate and DHEAS in 51 postmenopausal women in a randomized, placebo-controlled trial. We now report on the relationships between serum estrone sulfate and dehydroepiandrosterone sulfate (DHEAS) levels after 4 weeks of moderate alcohol supplementation, and compare the results to the 8 weeks data to elucidate time-to-effect differences. METHODS: Postmenopausal women (n = 51) consumed 0 (placebo), 15 (1 drink), and 30 (2 drinks) g alcohol (ethanol)/ day for 8 weeks as part of a controlled diet in a randomized crossover design. Blood samples were drawn at baseline, at 4 weeks and at 8 weeks. Changes in estrone sulfate and DHEAS levels from placebo to 15 g and 30 g alcohol per day were estimated using linear mixed models. RESULTS AND DISCUSSION: At week 4, compared to the placebo, estrone sulfate increased an average 6.9% (P = 0.24) when the women consumed 15 g of alcohol per day, and 22.2% (P = 0.0006) when they consumed 30 g alcohol per day. DHEAS concentrations also increased significantly by an average of 8.0% (P < 0.0001) on 15 g of alcohol per day and 9.2% (P < 0.0001) when 30 g alcohol was consumed per day. Trend tests across doses for both estrone sulfate (P = 0.0006) and DHEAS (P < 0.0001) were significant. We found no significant differences between the absolute levels of serum estrone sulfate at week 4 versus week 8 (P = 0.32) across all doses. However, absolute DHEAS levels increased from week 4 to week 8 (P < 0.0001) at all three dose levels. CONCLUSIONS: These data indicate that the hormonal effects due to moderate alcohol consumption are seen early, within 4 weeks of initiation of ingestion