An organotypical in vitro model for vascular tissue remodelling and its application to study radiation effects

An organotypic in vitro model, to study vascular tissueremodeling, was evaluated as a function of culture period. Inorder to validate the model as a tool for studying vascularresponses to damage, a dose-response analysis to ionizingirradiation was included.Rat aortic rings were explanted in vitro after being irradiatedwith single doses of ⁶⁰Co -rays, namely 0, 5, 10, 15, 20or 25 Gy. Irradiated and sham-irradiated aortic rings werecultured for 3 weeks. Explant outgrowth on an adhesivesubstrate was evaluated by macroscopical scoring, and ringsderived from each irradiation group together with theoutgrowths were fixed and embedded in paraffin after 2, 7, 14and 21 days. Bromodeoxyuridine incorporation, smoothmuscle actin and collagen types I and III were scored onimmunohistochemically stained sections. For each studiedparameter, irradiated and sham-irradiated rings were compared.In cultures of sham-irradiated rings, alterations from acontractile towards a synthetic/migratory smooth muscle cellphenotype were confirmed. After 3 weeks, fullgrown cultures hadformed. Irradiation slowed down the phenotypical modifications.After 15 Gy, irradiation explant outgrowth was already retarded;after 25 Gy, the outgrowth was completely blocked. On the otherhand, a dose of 15 Gy or more induced an increased collagen Iproduction in the tunica media.In conclusion, the present organotypical in vitro model fits toanalyse dynamics in the original vascular tissues as well as inthe primary outgrowth. It enables to confirm features oftissular reorganization and effects of ionizing radiationdescribed in vivo.     

Intravaginal practices, bacterial vaginosis, and HIV infection in women: individual participant data meta-analysis

Background

Identifying modifiable factors that increase women''s vulnerability to HIV is a critical step in developing effective female-initiated prevention interventions. The primary objective of this study was to pool individual participant data from prospective longitudinal studies to investigate the association between intravaginal practices and acquisition of HIV infection among women in sub-Saharan Africa. Secondary objectives were to investigate associations between intravaginal practices and disrupted vaginal flora; and between disrupted vaginal flora and HIV acquisition.

Methods and Findings

We conducted a meta-analysis of individual participant data from 13 prospective cohort studies involving 14,874 women, of whom 791 acquired HIV infection during 21,218 woman years of follow-up. Data were pooled using random-effects meta-analysis. The level of between-study heterogeneity was low in all analyses (I ² values 0.0%–16.1%). Intravaginal use of cloth or paper (pooled adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.18–1.83), insertion of products to dry or tighten the vagina (aHR 1.31, 95% CI 1.00–1.71), and intravaginal cleaning with soap (aHR 1.24, 95% CI 1.01–1.53) remained associated with HIV acquisition after controlling for age, marital status, and number of sex partners in the past 3 months. Intravaginal cleaning with soap was also associated with the development of intermediate vaginal flora and bacterial vaginosis in women with normal vaginal flora at baseline (pooled adjusted odds ratio [OR] 1.24, 95% CI 1.04–1.47). Use of cloth or paper was not associated with the development of disrupted vaginal flora. Intermediate vaginal flora and bacterial vaginosis were each associated with HIV acquisition in multivariable models when measured at baseline (aHR 1.54 and 1.69, p<0.001) or at the visit before the estimated date of HIV infection (aHR 1.41 and 1.53, p<0.001), respectively.

Conclusions

This study provides evidence to suggest that some intravaginal practices increase the risk of HIV acquisition but a direct causal pathway linking intravaginal cleaning with soap, disruption of vaginal flora, and HIV acquisition has not yet been demonstrated. More consistency in the definition and measurement of specific intravaginal practices is warranted so that the effects of specific intravaginal practices and products can be further elucidated. Please see later in the article for the Editors'' Summary     

Halacaridae (Acari) from Pujada Bay (the Philippines): description and biogeography of three new and two known species

Three new and two known Halacaridae species belonging to the genus Copidognathus collected among seagrass plants in Pujada Bay (Mindanao, the Philippines) are described. Copidognathus ivanomorsellii sp.n. belongs to the `Copidognathus gibbus' group and shows the main characteristics of the group but differs from known species as the two triangular porose areolae on AD are joined together, the typical shape of the lateral line of the costae of PD, the distance between the anterior gland pore on PD and the lateral margin of PD, tarsi III and IV with 4:4 dorsal setae, ventral seta on trochanter III almost as long as ventral seta of basifemur III, anterior end of AD with rosette pores, AE and GA only laterally fused but separated in the middle portion and elongated frontal spine (projection) on AD, lateral claws with very fine pecten ventrally. A zoogeographical distribution of the `C. gibbus' group is reported. Copidognathus pujadus sp.n. belongs to the `Copidognathus bairdi' group and is loosely related to C. sideus Bartsch, 1982, C. sidellus Bartsch, 1985 and C. euryalus Bartsch, 1997b. Differences were observed and are discussed. Copidognathus philippinensis sp.n. belongs to the `Copidognathus curassaviensis' group but differs from the four known species within the group by the elevated ridge below the middle two areolae on AD area which connects the two areolae. In addition, two known species i.e. Copidognathus uniscutatus Bartsch, 1984, C. faubeli Bartsch, 1986 were collected. The Halacaridae fauna recorded so far from the Philippines is summarised and discussed.     

The Contribution of Emotional Partners to Sexual Risk Taking and Violence among Female Sex Workers in Mombasa,Kenya: A Cohort Study

Objectives

To assess sexual risk-taking of female sex workers (FSWs) with emotional partners (boyfriends and husbands), compared to regular and casual clients. Experiences of violence and the degree of relationship control that FSWs have with emotional partners are also described.

Design

Cohort study with quarterly follow-up visit over 12-months.

Methods

Four hundred HIV-uninfected FSWs older than 16 years were recruited from their homes and guesthouses in Mombasa, Kenya. A structured questionnaire assessed participant characteristics and study outcomes at each visit, and women received risk-reduction counselling, male and female condoms, and HIV testing.

Results

Four or more unprotected sex acts in the past week were reported by 21.3% of women during sex with emotional partners, compared to 5.8% with regular and 4.8% with casual clients (P<0.001). Total number of unprotected sex acts per week was 5–6-fold higher with emotional partners (603 acts with 259 partners) than with regular or casual clients (125 acts with 456, and 98 acts with 632 clients, respectively; P<0.001). Mostly, perceptions of “trust” underscored unprotected sex with emotional partners. Low control over these relationships, common to many women (36.9%), was linked with higher partner numbers, inconsistent condom use, and being physically forced to have sex by their emotional partners. Half experienced sexual or physical violence in the past year, similarly associated with partner numbers and inconsistent condom use.

Conclusions

High-risk sexual behaviour, low control and frequent violence in relationships with emotional partners heighten FSWs'' vulnerability and high HIV risk, requiring targeted interventions that also encompass emotional partners.     

Bacterial Colonization on Fecal Pellets of Harpacticoid Copepods and on Their Diatom Food

Fecal pellets make up a significant fraction of the global flux of organic matter in oceans, and the associated bacterial communities in particular are a potential food source for marine organisms. However, these communities remain largely unknown. In the present study, the bacterial communities on fecal pellets of the benthic copepod Paramphiascella fulvofasciata feeding on the diatoms Navicula phyllepta and Seminavis robusta were analyzed. The aim of this study was to characterize the bacterial communities associated with the diatoms and the fecal pellets by means of DGGE profiling. Furthermore, isolated bacteria were characterized by means of partial 16S rRNA gene sequencing. The composition of the bacterial microflora on fecal pellets was studied in terms of the effect of the original food source, the age of the fecal pellets and the copepod’s identity. Alphaproteobacteria, Flavobacteria, and Bacilli were found on the fecal pellets; whereas on diatoms, exclusively Gammaproteobacteria were identified. Especially after eating N. phyllepta, there was an important increase in bacterial diversity, although the diatom N. phyllepta harbored a less diverse bacterial community than S. robusta. Our data suggest that the additional bacteria originate from the copepod’s digestive tract and largely depends on the initial food source.     

Analytical Performance of the Roche LightCycler? Mycobacterium Detection Kit for the Diagnosis of Clinically Important Mycobacterial Species

Background

The LightCycler® Mycobacterium Detection Kit based on real-time PCR technology for the detection of Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium kansasii was recently developed. This study evaluated its analytical sensitivity, specificity and reproducibility.

Methodology/Principal Findings

Plasmid standards were prepared and used to determine the limit of detection. The assay was also performed against organisms other than mycobacteria, other mycobacterial strains and interfering substances to exclude cross-reactivity and interference. Reference standards were prepared and tested to assess the assay''s reproducibility. All PCR assays were performed using the LightCycler® 2.0 Instrument. The detection limit for M. tuberculosis was 28 copies per microlitre. Neither cross-reactivity nor interference occurred with non-mycobacterial organisms and substances tested. Overall reproducibility for consecutive measurements, run-to-run, lot-to-lot, day-to-day and laboratory-to-laboratory achieved a coefficient of variance of less than two percent.

Significance

The LightCycler® Mycobacterium Detection kit has shown to be a robust and accurate assay with the potential to be used as a rapid TB diagnostic test.     

UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili

Archaea, like bacteria and eukaryotes, contain proteins involved in various mechanisms of DNA repair, highlighting the importance of these processes for all forms of life. Species of the order Sulfolobales of hyperthermophilic crenarchaeota are equipped with a strongly UV-inducible type IV pilus system that promotes cellular aggregation. Here we demonstrate by fluorescence in situ hybridization that cellular aggregates are formed based on a species-specific recognition process and that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency. Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Knockout strains of Sulfolobus acidocaldarius incapable of pilus production could not self-aggregate, but were partners in mating experiments with wild-type strains indicating that one cellular partner can mediate the DNA transfer. Since pilus knockout strains showed decreased survival upon UV treatment, we conclude that the UV-inducible DNA transfer process and subsequent homologous recombination represents an important mechanism to maintain chromosome integrity in Sulfolobus. It might also contribute substantially to the frequent chromosomal DNA exchange and horizontal gene transfer in these archaea in their natural habitat.     

Dectin-1 interaction with tetraspanin CD37 inhibits IL-6 production

C-type lectins are pattern-recognition receptors important for pathogen binding and uptake by APCs. Evidence is accumulating that integration of incoming cellular signals in APCs is regulated by grouping of receptors and signaling molecules into organized membrane complexes, such as lipid rafts and tetraspanin microdomains. In this study, we demonstrate that C-type lectin dectin-1 functionally interacts with leukocyte-specific tetraspanin CD37. Dectin-1 and CD37 colocalize on the surface of human APCs. Importantly, macrophages of CD37-deficient (CD37(-/-)) mice express decreased dectin-1 membrane levels, due to increased dectin-1 internalization. Furthermore, transfection of CD37 into a macrophage cell line elevated endogenous dectin-1 surface expression. Although CD37 deficiency does not affect dectin-1-mediated phagocytosis, we observed a striking 10-fold increase of dectin-1-induced IL-6 production in CD37(-/-) macrophages compared with wild-type cells, despite reduced dectin-1 cell surface expression. Importantly, the observed increase in IL-6 production was specific for dectin-1, because signaling via other pattern-recognition receptors was unaffected in CD37(-/-) macrophages and because the dectin-1 ligand curdlan was used. Taken together, these findings show that tetraspanin CD37 is important for dectin-1 stabilization in APC membranes and controls dectin-1-mediated IL-6 production.