Dynamic sex chromosomes in Old World chameleons (Squamata: Chamaeleonidae).

Much of our current state of knowledge concerning sex chromosome evolution is based on a handful of 'exceptional' taxa with heteromorphic sex chromosomes. However, classifying the sex chromosome systems of additional species lacking easily identifiable, heteromorphic sex chromosomes is indispensable if we wish to fully understand the genesis, degeneration and turnover of vertebrate sex chromosomes. Squamate reptiles (lizards and snakes) are a potential model clade for studying sex chromosome evolution as they exhibit a suite of sex-determining modes yet most species lack heteromorphic sex chromosomes. Only three (of 203) chameleon species have identified sex chromosome systems (all with female heterogamety, ZZ/ZW). This study uses a recently developed method to identify sex-specific genetic markers from restriction site-associated DNA sequence (RADseq) data, which enables the identification of sex chromosome systems in species lacking heteromorphic sex chromosomes. We used RADseq and subsequent PCR validation to identify an XX/XY sex chromosome system in the veiled chameleon (Chamaeleo calyptratus), revealing a novel transition in sex chromosome systems within the Chamaeleonidae. The sex-specific genetic markers identified here will be essential in research focused on sex-specific, comparative, functional and developmental evolutionary questions, further promoting C. calyptratus' utility as an emerging model organism.

Meta-analysis of randomized and quasi-randomized clinical trials of topical antibiotics after primary closure for the prevention of surgical-site infection.

BACKGROUND: Surgical-site infections (SSIs) increase patient morbidity and costs. The aim was to identify and synthesize all RCTs evaluating the effect of topical antibiotics on SSI in wounds healing by primary intention. METHODS: The search included Ovid MEDLINE, Ovid Embase, the Cochrane Wounds Specialized Register, Central Register of Controlled Trials and EBSCO CINAHL from inception to May 2016. There was no restriction of language, date or setting. Two authors independently selected studies, extracted data and assessed risk of bias. When sufficient numbers of comparable trials were available, data were pooled in meta-analysis. RESULTS: Fourteen RCTs with 6466 participants met the inclusion criteria. Pooling of eight trials (5427 participants) showed that topical antibiotics probably reduced the risk of SSI compared with no topical antibiotic (risk ratio (RR) 0·61, 95 per cent c.i. 0·42 to 0·87; moderate-quality evidence), equating to 20 fewer SSIs per 1000 patients treated. Pooling of three trials (3012 participants) for risk of allergic contact dermatitis found no clear difference between antibiotics and no antibiotic (RR 3·94, 0·46 to 34·00; very low-quality evidence). Pooling of five trials (1299 participants) indicated that topical antibiotics probably reduce the risk of SSI compared with topical antiseptics (RR 0·49, 0·30 to 0·80; moderate-quality evidence); 43 fewer SSIs per 1000 patients treated. Pooling of two trials (541 participants) showed no clear difference in the risk of allergic contact dermatitis with antibiotics or antiseptic agents (RR 0·97, 0·52 to 1·82; very low-quality evidence). CONCLUSION: Topical antibiotics probably prevent SSI compared with no topical antibiotic or antiseptic. No conclusion can be drawn regarding whether they cause allergic contact dermatitis.

Cimetidine is an antiandrogen in the rat.

Cimetidine has been associated with gynecomastia as a side effect. Because other antiandrogens have been linked to the development of breast enlargement in men, the suggestion by earlier workers that cimetidine possessed antiandrogenic properties prompted us to study the endocrine effects of cimetidine in rats. Cimetidine directly antagonized the effects of exogenously administered testosterone on androgen target tissues. Ventral prostate and seminal vesicle weights were less in cimetidine-treated castrate adult male rats androgenized with testosterone-filled subcutaneous silastic capsules than in vehicle-injected controls. Cimetidine possessed no intrinsic androgen-like bioactivity in prepubertal male rats when given in doses of 50 mg/kg/day for 1 wk. Cimetidine competitively inhibited DHT binding to its cytoplasmic receptor and decreased specific nuclear uptake of [3H]dihydrotestosterone in rat ventral prostate slices. No effects on plasma gonadotropin or testosterone concentrations were observed. We conclude that cimetidine is a nonsteroidal-antiandrogen and that this property may contribute to the production of gynecomastia in cimetidine-treated men.

Sequence and topology of the CorA magnesium transport systems of Salmonella typhimurium and Escherichia coli. Identification of a new class of transport protein.

The CorA Mg2+ transport systems of Salmonella typhimurium and Escherichia coli mediate both influx and efflux of Mg2+. The product of the CorA locus is sufficient for mediation of Mg2+ influx while product(s) of the unlinked CorBCD loci allow CorA to mediate efflux in addition to influx. The nucleotide sequences of the S. typhimurium and E. coli CorA loci have been determined. The locus in each species consists of a single gene expressing a protein with gel molecular masses of 42 kDa (S. typhimurium) and 39 kDa (E. coli). The predicted amino acid sequences of these proteins are each 316 amino acids in length, are 98% identical, and lack homology to any known protein. Although CorA is an integral membrane protein by biochemical criteria, its predicted amino acid sequence contains 28% charged amino acid. Membrane localization of CorA was shown to be dependent on the Sec pathway in E. coli. Hydropathy analysis predicts two C-terminal hydrophobic sequences of sufficient length to span the membrane bilayer. The membrane topology of CorA was determined by constructing deletion derivatives of CorA and genetically fusing them to BlaM or LacZ cassettes. The enzymatic activities of these hybrid proteins indicate that the N-terminal 235 amino acid residues of the CorA protein are located within the periplasmic space, comprising a single periplasmic domain. The C-terminal region of CorA is composed of three membrane-spanning segments rather than the two suggested by hydropathy plots, thus depositing the C terminus within the cytoplasm. This topology suggests that CorA functions as an oligomer since three membrane loops are most likely insufficient for any sort of membrane pore or channel. Its lack of homology to known proteins and its topology indicate that the CorA Mg2+ transporter represents a new class of membrane transport system.