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Now showing 1 - 10 of 48
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    Violence against women in sex work and HIV risk implications differ qualitatively by perpetrator.
    Decker, Michele R.; Pearson, Erin; Illangasekare, Samantha L.; Clark, Erin; Sherman, Susan G. (BioMed Central, 2013-09-23)
    BACKGROUND: Physical and sexual violence heighten STI/HIV risk for women in sex work. Against this backdrop, we describe the nature of abuse against women in sex work, and its STI/HIV implications, across perpetrators. METHODS: Adult women involved in sex work (n = 35) in Baltimore, MD participated in an in-depth interview and brief survey. RESULTS: Physical and sexual violence were prevalent, with 43% reporting past-month abuse. Clients were the primary perpetrators; their violence was severe, compromised women's condom and sexual negotiation, and included forced and coerced anal intercourse. Sex work was a factor in intimate partner violence. Police abuse was largely an exploitation of power imbalances for coerced sex. CONCLUSIONS: Findings affirm the need to address physical and sexual violence, particularly that perpetrated by clients, as a social determinant of health for women in sex work, as well as a threat to safety and wellbeing, and a contextual barrier to HIV risk reduction.
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    Basic linker of macroH2A stabilizes DNA at the entry/exit site of the nucleosome
    Chakravarthy, Srinivas; Patel, Ashok; Bowman, Gregory D. (Oxford University Press, 2012-06-29)
    MacroH2A is a histone H2A variant that is typically found in heterochromatic regions of the genome. A positively charged linker that connects the histone-fold with the macro-domain was suggested to have DNA-binding properties, and has been shown to promote oligomerization of chromatin fibers. Here we examine the influence of this basic linker on DNA of mononucleosomes. We find that the macro-linker reduces accessibility to extranucleosomal DNA, and appears to increase compaction of the nucleosome. These properties arise from interactions between the H1-like basic linker region and DNA around the entry/exit site, which increases protection of nucleosomal DNA from exonuclease III digestion by 10 bp. By stabilizing the wrapping of DNA around the histone core, this basic linker of macroH2A may alter the distribution of nucleosome-associated factors, and potentially contribute to the more compacted nature of heterochromatin.
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    Pulmonary Tuberculosis Incidence and Risk Factors in Rural Areas of China: A Cohort Study
    Chen, Wei; Shu, Wen; Wang, Min; Hou, Yongchun; Xia, Yinyin; Xu, Weiguo; Bai, Liqiong; Nie, Shaofa; Cheng, Shiming; Xu, Yihua (PLoS Organization, 2013-03-12)
    The incidence of tuberculosis (TB) and its risk factors in China remains unclear. This study examined TB incidence and relative risk factors in rural areas of China. Participants (n = 177,529) were recruited in Xiangtan County (in the central area of China) and in Danyang County (in the eastern area of China) in 2009 and a followed-up study was conducted for one year. The incidence density of pulmonary TB and smear-positive TB were 91.6 (95% CI: 78.7, 106.0) per 100,000 person-year and 36.7 (95% CI: 33.1, 52.4) per 100,000 person-year respectively in Xiangtan, and 47.3 (95% CI: 38.2, 57.5) per 100,000 person-year and 22.7 (95% CI: 16.5, 30.8) per 100,000 person-year in Danyang. The medical history of TB was associated with TB, with the relative risk (RR) of 7.00 (95% CI: 2.76, 17.18) in Xiangtan and that of 31.08 (95% CI: 13.22, 73.10) in Danyang. The association between TB and per capita living space over median was found in Xiangtan, with the RR of 1.86 (95% CI: 1.15, 3.01). No association was found between TB and the insurance status, the contact history with TB, the history of diabetes, smoking, or per capita annual income. The host genetic susceptibility, and social factors such as education and income could be considered in future studies.
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    Comparison of Sum Absolute QRST Integral, and Temporal Variability in Depolarization and Vectorcardiography Approach, in Healthy Men and Women
    Sur, Sanjoli; Han, Lichy; Tereshchenko, Larisa G. (PLoS Organization, 2013-02-22)
    BACKGROUND: Recently we showed the predictive value of sum absolute QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women. METHODS: Orthogonal ECGs were recorded at rest for 10 minutes in 160 healthy men and women (mean age 39.6±14.6, 80 men). Mean spatial TT' angle, and normalized variances of T loop area, of spatial T vector amplitude, of QT interval and Tpeak-Tend area were measured for assessment of repolarization lability. Normalized variances of spatial QRS vector and QRS loop area characterized variability of depolarization. In addition, variability indices (VI) were calculated to adjust for normalized heart rate variance. SAI QRST was measured as the averaged arithmetic sum of areas under the QRST curve. RESULTS: Men were characterized by shorter QTc (430.3±21.7 vs. 444.7±22.2 ms; P<0.0001) and larger SAI QRST (282.1±66.7 vs. 204.9±58.5 mV*ms; P<0.0001). Repolarization lability negatively correlated with spatial T vector amplitude. Adjusted by normalized heart rate variance, QT variability index was significantly higher in women than in men (-1.54±0.38 vs. -1.70±0.33; P = 0.017). However, in multivariate logistic regression after adjustment for body surface area, QTc, and spatial T vector amplitude, healthy men had 1.5-3 fold higher probability of having larger repolarization lability, as compared to healthy women (T vector amplitude variability index odds ratio 3.88 (95%CI 1.4-11.1; P = 0.012). CONCLUSIONS: Healthy men more likely than women have larger repolarization liability.
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    Mechanisms of Siglec-F-induced eosinophil apoptosis: a role for caspases but not for SHP-1, Src kinases, NADPH oxidase or reactive oxygen.
    Mao, Hui; Kano, Gen; Hudson, Sherry A.; Brummet, Mary; Zimmermann, Nives; Zhu, Zhou; Bochner, Bruce S. (PLoS Organization, 2013-06-28)
    Abstract BACKGROUND: Siglec-F and Siglec-8 are functional paralog proapoptotic cell surface receptors expressed on mouse and human eosinophils, respectively. Whereas Siglec-8 mediated death involves caspases and/or reactive oxygen species (ROS) generation and mitochondrial injury, very little is known about Siglec-F-mediated signaling and apoptosis. Therefore the objective of the current experiments was to better define apoptosis pathways mediated by Siglec-F and Siglec-8. Given that Siglec-F-induced apoptosis is much less robust than Siglec-8-induced apoptosis, we hypothesized that mechanisms involved in cell death via these receptors would differ. METHODS: Consequences of engagement of Siglec-F on mouse eosinophils were studied by measuring ROS production, and by performing apoptosis assays using eosinophils from normal, hypereosinophilic, NADPH oxidase-deficient, src homology domain-containing protein tyrosine phosphatase (SHP)-1-deficient, and Lyn kinase-deficient mice. Inhibitors of caspase and Src family kinase activity were also used. RESULTS: Engagement of Siglec-F induced mouse eosinophil apoptosis that was modest in magnitude and dependent on caspase activity. There was no detectable ROS generation, or any role for ROS, NADPH oxidase, SHP-1, or Src family kinases in this apoptotic process. CONCLUSIONS: These data suggest that Siglec-F-mediated apoptosis is different in both magnitude and mechanisms when compared to published data on Siglec-8-mediated human eosinophil apoptosis. One likely implication of this work is that models targeting Siglec-F in vivo in mice may not provide identical mechanistic predictions for consequences of Siglec-8 targeting in vivo in humans.
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    LINC-anchored actin cap connects the extracellular milieu to the nucleus for ultrafast mechanotransduction
    Chambliss, Allison B.; Khatau, Shyam B.; Erdenberger, Nicholas; Robinson, D. Kyle; Hodzic, Didier; Longmore, Gregory D.; Wirtz, Denis (Nature Publishing Group, 2013-01-18)
    Cells continuously sense and respond to external mechanical forces through their cytoskeleton. Here we show that only a small subset of actin fibers, those forming the perinuclear actin cap that wraps around the nucleus, form in response to low physiological mechanical stresses in adherent fibroblasts. While conventional basal stress fibers form only past a threshold shear stress of 0.5 dyn/cm(2), actin-cap fibers are formed at shear stresses 50 times lower and orders-of-magnitude faster than biochemical stimulation. This fast differential response is uniquely mediated by focal adhesion protein zyxin at low shear stress and actomyosin fibers of the actin cap. We identify additional roles for lamin A/C of the nuclear lamina and linkers of nucleus to cytoskeleton (LINC) molecules nesprin2giant and nesprin3, which anchor actin cap fibers to the nucleus. These results suggest an interconnected physical pathway for mechanotransduction, from the extracellular milieu to the nucleus.
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    Morphological characterization of bushy cells and their inputs in the laboratory mouse (Mus musculus) anteroventral cochlear nucleus.
    Lauer, Amanda M.; Connelly, Catherine J.; Graham, Heather; Ryugo, David K. (PLoS Organization, 2013-08-26)
    Spherical and globular bushy cells of the AVCN receive huge auditory nerve endings specialized for high fidelity neural transmission in response to acoustic events. Recent studies in mice and other rodent species suggest that the distinction between bushy cell subtypes is not always straightforward. We conducted a systematic investigation of mouse bushy cells along the rostral-caudal axis in an effort to understand the morphological variation that gives rise to reported response properties in mice. We combined quantitative light and electron microscopy to investigate variations in cell morphology, immunostaining, and the distribution of primary and non-primary synaptic inputs along the rostral-caudal axis. Overall, large regional differences in bushy cell characteristics were not found; however, rostral bushy cells received a different complement of axosomatic input compared to caudal bushy cells. The percentage of primary auditory nerve terminals was larger in caudal AVCN, whereas non-primary excitatory and inhibitory inputs were more common in rostral AVCN. Other ultrastructural characteristics of primary auditory nerve inputs were similar across the rostral and caudal AVCN. Cross sectional area, postsynaptic density length and curvature, and mitochondrial volume fraction were similar for axosomatic auditory nerve terminals, although rostral auditory nerve terminals contained a greater concentration of synaptic vesicles near the postsynaptic densities. These data demonstrate regional differences in synaptic organization of inputs to mouse bushy cells rather than the morphological characteristic of the cells themselves.
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    Bacterial expression strategies for several Sus scrofa diacylglycerol kinase alpha constructs: solubility challenges.
    Petro, Elizabeth J.; Raben, Daniel M. (Nature Publishing Group, 2013-04-05)
    We pursued several strategies for expressing either full-length Sus scrofa diacylglycerol kinase (DGK) alpha or the catalytic domain (alphacat) in Escherichia coli. Alphacat could be extracted, refolded, and purified from inclusion bodies, but when subjected to analytical gel filtration chromatography, it elutes in the void volume, in what we conclude are microscopic aggregates unsuitable for x-ray crystallography. Adding glutathione S-transferase, thioredoxin, or maltose binding protein as N-terminal fusion tags did not improve alphacat's solubility. Coexpressing with bacterial chaperones increased the yield of alphacat in the supernatant after high-speed centrifugation, but the protein still elutes in the void upon analytical gel filtration chromatography. We believe our work will be of interest to those interested in the structure of eukaryotic DGKs, so that they know which expression strategies have already been tried, as well as to those interested in protein folding and those interested in chaperone/target-protein interactions
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    Increased flap weight and decreased perforator number predict fat necrosis in DIEP breast reconstruction
    Mulvey, Carolyn L.; Cooney, Carisa M.; Daily, Francis F.; Colantuoni, Elizabeth; Ogbuago, Onyebuchi U.; Cooney, Damon S.; Rad, Ariel N.; Manahan, Michele A.; Rosson, Gedge D.; Sacks, Justin M. (American Society of Plastic Surgeons, 2013-05-28)
    BACKGROUND: Compromised perfusion in autologous breast reconstruction results in fat necrosis and flap loss. Increased flap weight with fewer perforator vessels may exacerbate imbalances in flap perfusion. We studied deep inferior epigastric perforator (DIEP) and muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps to assess this concept. METHODS: Data from patients who underwent reconstruction with DIEP and/or MS-TRAM flaps between January 1, 2010 and December 31, 2011 (n = 123) were retrospectively reviewed. Patient demographics, comorbidities, intraoperative parameters, and postoperative outcomes were collected, including flap fat necrosis and donor/recipient site complications. Logistic regression analysis was used to examine effects of flap weight and perforator number on breast flap fat necrosis. RESULTS: One hundred twenty-three patients who underwent 179 total flap reconstructions (166 DIEP, 13 MS-TRAM) were included. Mean flap weight was 658 ± 289 g; 132 (73.7%) were single perforator flaps. Thirteen flaps (7.5%) developed fat necrosis. African American patients had increased odds of fat necrosis (odds ratio, 11.58; P < 0.001). Odds of developing fat necrosis significantly increased with flap weight (odds ratio, 1.5 per 100 g increase; P < 0.001). In single perforator flaps weighing more than 1000 g, six (42.9%) developed fat necrosis, compared to 14.3% of large multiple perforator flaps. CONCLUSIONS: Flaps with increasing weight have increased risk of fat necrosis. These data suggest that inclusion of more than 1 perforator may decrease odds of fat necrosis in large flaps. Perforator flap breast reconstruction can be performed safely; however, considerations concerning race, body mass index, staging with tissue expanders, perforator number, and flap weight may optimize outcomes.
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    Improving teaching on an inpatient pediatrics service: a retrospective analysis of a program change
    Barone, Michael; Dudas, Robert; Stewart, Rosalyn; McMillan, Julia; Dover, George; Serwint, Janet (BioMed Central, 2012-10-01)
    Background: The traditional role of the faculty inpatient attending providing clinical care and effectively teaching residents and medical students is threatened by increasing documentation requirements, pressures to increase clinical productivity, and insufficient funding available for medical education. In order to sustain and improve clinical education on a general pediatric inpatient service, we instituted a comprehensive program change. Our program consisted of creating detailed job descriptions, setting clear expectations, and providing salary support for faculty inpatient attending physicians serving in clinical and educational roles. This study was aimed at assessing the impact of this program change on the learners’ perceptions of their faculty attending physicians and learners’ experiences on the inpatient rotations. Methods: We analyzed resident and medical student electronic evaluations of both clinical and teaching faculty attending physician characteristics, as well as resident evaluations of an inpatient rotation experience. We compared the proportions of “superior” ratings versus all other ratings prior to the educational intervention (2005–2006, baseline) with the two subsequent years post intervention (2006–2007, year 1; 2007–2008, year 2). We also compared medical student scores on a comprehensive National Board of Medical Examiners clinical subject examination pre and post intervention. Results: When compared to the baseline year, pediatric residents were more likely to rate as superior the quality of didactic teaching (OR=1.7 [1.0-2.8] year 1; OR=2.0 [1.1-3.5] year 2) and attendings’ appeal as a role model (OR=1.9 [1.1-3.3] year 2). Residents were also more likely to rate as superior the quality of feedback and evaluation they received from the attending (OR=2.1 [1.2-3.7] year 1; OR=3.9 [2.2-7.1] year 2). Similar improvements were also noted in medical student evaluations of faculty attendings. Most notably, medical students were significantly more likely to rate feedback on their data gathering and physical examination skills as superior (OR=4.2 [2.0-8.6] year 1; OR=6.4 [3.0-13.6] year 2). Conclusions: A comprehensive program which includes clear role descriptions along with faculty expectations, as well as salary support for faculty in clinical and educational roles, can improve resident and medical student experiences on a general pediatric inpatient service. The authors provide sufficient detail to replicate this program to other settings.