238 research outputs found

    Conical Defects in Higher Spin Theories

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    We study conical defect geometries in the SL(N) Chern-Simons formulation of higher spin gauge theories in AdS_3. We argue that (for N\geq 4) there are special values of the deficit angle for which these geometries are actually smooth configurations of the underlying theory. We also exhibit a gauge in which these geometries can be viewed as wormholes interpolating between two distinct asymptotically AdS_3 spacetimes. Remarkably, the spectrum of smooth SL(N,C) solutions, after an appropriate analytic continuation, exactly matches that of the so-called "light primaries" in the minimal model W_N CFTs at finite N. This gives a candidate bulk interpretation of the latter states in the holographic duality proposed in [1].Comment: 38 page

    Menstrual function among women exposed to polybrominated biphenyls: A follow-up prevalence study

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    BACKGROUND: Alteration in menstrual cycle function is suggested among rhesus monkeys and humans exposed to polybrominated biphenyls (PBBs) and structurally similar polychlorinated biphenyls (PCBs). The feedback system for menstrual cycle function potentially allows multiple pathways for disruption directly through the hypothalamic-pituitary-ovarian axis and indirectly through alternative neuroendocrine axes. METHODS: The Michigan Female Health Study was conducted during 1997–1998 among women in a cohort exposed to PBBs in 1973. This study included 337 women with self-reported menstrual cycles of 20–35 days (age range: 24–56 years). Current PBB levels were estimated by exponential decay modeling of serum PBB levels collected from 1976–1987 during enrollment in the Michigan PBB cohort. Linear regression models for menstrual cycle length and the logarithm of bleed length used estimated current PBB exposure or enrollment PBB exposure categorized in tertiles, and for the upper decile. All models were adjusted for serum PCB levels, age, body mass index, history of at least 10% weight loss in the past year, physical activity, smoking, education, and household income. RESULTS: Higher levels of physical activity were associated with shorter bleed length, and increasing age was associated with shorter cycle length. Although no overall association was found between PBB exposure and menstrual cycle characteristics, a significant interaction between PBB exposures with past year weight loss was found. Longer bleed length and shorter cycle length were associated with higher PBB exposure among women with past year weight loss. CONCLUSION: This study suggests that PBB exposure may impact ovarian function as indicated by menstrual cycle length and bleed length. However, these associations were found among the small number of women with recent weight loss suggesting either a chance finding or that mobilization of PBBs from lipid stores may be important. These results should be replicated with larger numbers of women exposed to similar lipophilic compounds

    The effects of tualang honey on female reproductive organs, tibia bone and hormonal profile in ovariectomised rats - animal model for menopause

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    <p>Abstract</p> <p>Background</p> <p>Honey is a highly nutritional natural product that has been widely used in folk medicine for a number of therapeutic purposes. We evaluated whether Malaysian Tualang honey (AgroMas, Malaysia) was effective in reducing menopausal syndrome in ovariectomised female rats; an animal model for menopause.</p> <p>Methods</p> <p>The rats were divided into two control groups and three test groups. The control groups were sham-operated (SH) and ovariectomised (OVX) rats. The SH and OVX control rats were fed on 0.5 ml of distill water. The rats in the test groups were fed with low dose 0.2 g/kg (THL), medium dose, 1.0 g/kg (THM) and high dose 2.0 g/kg (THH) of Tualang honey in 0.5 ml of distill water. The administration was given by oral gavage once daily for 2 weeks. The reproductive organs (uterus and vagina), tibia bone and aorta were taken for histopathological examination while serum for hormonal assays.</p> <p>Results</p> <p>Administration of Tualang honey for 2 weeks to ovariectomised rats significantly increased the weight of the uterus and the thickness of vaginal epithelium, restored the morphology of the tibia bones and reduced the body weight compared to rats in the ovariectomised group. The levels of estradiol and progesterone, in honey treated groups were markedly lower than that in the OVX group. At low doses (0.2 g/kg; THL group) of Tualang honey there was an increased in serum free testosterone levels compared to OVX group (P < 0.01). Progesterone concentrations was significantly decreased in the OVX group as compared to SHAM group (P < 0.05).</p> <p>Conclusions</p> <p>Tualang honey was shown to have beneficial effects on menopausal (ovariectomised) rats by preventing uterine atrophy, increased bone density and suppression of increased body weight. Honey could be an alternative to HRT.</p

    Endometrial stromal sarcoma: a population-based analysis

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    To determine independent prognostic factors for the survival of patients with endometrial stromal sarcoma (ESS), data were abstracted from the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute from 1988 to 2003. Kaplan–Meier and Cox proportional hazards models were used for analyses. Of 831 women diagnosed with ESS, the median age was 52 years (range: 17–96 years). In total, 59.9% had stage I, 5.1% stage II, 14.9% stage III, and 20.1% had stage IV disease. Overall, 13.0, 36.1, and 34.7% presented with grades 1, 2, and 3, respectively. Patients with stage I–II vs III–IV disease had 5 years DSS of 89.3% vs 50.3% (P<0.001) and those with grades 1, 2, and 3 cancers had survivals of 91.4, 95.4, and 42.1% (P<0.001). In multivariate analysis, older patients, black race, advanced stage, higher grade, lack of primary surgery, and nodal metastasis were independent prognostic factors for poorer survival. In younger women (<50 years) with stage I–II disease, ovarian-sparing procedures did not adversely impact survival (91.9 vs 96.2%; P=0.1). Age, race, primary surgery, stage, and grade are important prognostic factors for ESS. Excellent survival in patients with grade 1 and 2 disease of all stages supports the concept that these tumors are significantly different from grade 3 tumors. Ovarian-sparing surgeries may be considered in younger patients with early-stage disease

    Early menopause, association with tobacco smoking, coffee consumption and other lifestyle factors: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Early onset of menopause is a risk factor for several health problems. The objective was primarily to investigate the association between early menopause and current, past active and passive smoking. A second aim was to investigate the association between coffee and alcohol consumption and early menopause.</p> <p>Methods</p> <p>The present population-based cross-sectional study included a sub-sample of 2123 postmenopausal women born in 1940–41 who participated in the Oslo Health Study. Early menopause was defined as menopause occurring at an age of less than 45 years. We applied logistic regression analyses (crude and adjusted odds ratio (OR)) to examine the association between early menopause and selected lifestyle factors.</p> <p>Results</p> <p>Current smoking was significantly associated with early menopause (adj. OR, 1.59; 95% CI, 1.11–2.28). Stopping smoking more than 10 years before menopause considerably reduced the risk of early menopause (adj. OR, 0.13; 95% CI, 0.05–0.33). Total exposure to smoking (the product of number of cigarettes per day and time as a smoker) was positively related to early menopause and, at the highest doses, nearly doubled the odds (adj. OR, 1.93; 95% CI, 1.12–3.30). These data suggest a possible dose-response relationship between total exposure to smoking and early menopause, but no dose-response relationship was detected for the other variables examined. We found no significant association of coffee or alcohol consumption with early menopause. Of the lifestyle factors tested, high educational level (adj. OR, 0.50; 95% CI, 0.34–0.72) and high social participation (adj. OR, 0.60, 95% CI, 0.39–0.98) were negatively associated with early menopause.</p> <p>Conclusion</p> <p>This cross-sectional study shows an association between current smoking and early menopause. The data also suggest that the earlier a woman stops smoking the more protected she is from early menopause. Early menopause was not significantly associated with passive smoking, or alcohol or coffee consumption.</p

    Surface Localization of Glucosylceramide during Cryptococcus neoformans Infection Allows Targeting as a Potential Antifungal

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    Cryptococcus neoformans (Cn) is a significant human pathogen that, despite current treatments, continues to have a high morbidity rate especially in sub-Saharan Africa. The need for more tolerable and specific therapies has been clearly shown. In the search for novel drug targets, the gene for glucosylceramide synthase (GCS1) was deleted in Cn, resulting in a strain (Δgcs1) that does not produce glucosylceramide (GlcCer) and is avirulent in mouse models of infection. To understand the biology behind the connection between virulence and GlcCer, the production and localization of GlcCer must be characterized in conditions that are prohibitive to the growth of Δgcs1 (neutral pH and high CO2). These prohibitive conditions are physiologically similar to those found in the extracellular spaces of the lung during infection. Here, using immunofluorescence, we have shown that GlcCer localization to the cell surface is significantly increased during growth in these conditions and during infection. We further seek to exploit this localization by treatment with Cerezyme (Cz), a recombinant enzyme that metabolizes GlcCer, as a potential treatment for Cn. Cz treatment was found to reduce the amount of GlcCer in vitro, in cultures, and in Cn cells inhabiting the mouse lung. Treatment with Cz induced a membrane integrity defect in wild type Cn cells similar to Δgcs1. Cz treatment also reduced the in vitro growth of Cn in a dose and condition dependent manner. Finally, Cz treatment was shown to have a protective effect on survival in mice infected with Cn. Taken together, these studies have established the legitimacy of targeting the GlcCer and other related sphingolipid systems in the development of novel therapeutics

    Antidepressants and Breast and Ovarian Cancer Risk: A Review of the Literature and Researchers' Financial Associations with Industry

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    BACKGROUND: Antidepressant (AD) use has been purported to increase the risk of breast and ovarian cancer, although both epidemiological and pre-clinical studies have reported mixed results. Previous studies in a variety of biomedical fields have found that financial ties to drug companies are associated with favorable study conclusions. METHODS AND FINDINGS: We searched English-language articles in MEDLINE, PsychINFO, the Science Citations Index and the Cochrane Central Register of Controlled Clinical Trials (through November 2010). A total of 61 articles that assessed the relationship between breast and ovarian cancer and AD use and articles that examined the effect of ADs on cell growth were included. Multi-modal screening techniques were used to investigate researchers' financial ties with industry. A random effects meta-analysis was used to pool the findings from the epidemiological literature. Thirty-three percent (20/61) of the studies reported a positive association between ADs and cancer. Sixty-seven percent (41/61) of the studies reported no association or antiproliferative effect. The pooled odds ratio for the association between AD use and breast/ovarian cancer in the epidemiologic studies was 1.11 (95% CI, 1.03-1.20). Researchers with industry affiliations were significantly less likely than researchers without those ties to conclude that ADs increase the risk of breast or ovarian cancer. (0/15 [0%] vs 20/46 [43.5%] (Fisher's Exact test P = 0.0012). CONCLUSIONS: Both the pre-clinical and clinical data are mixed in terms of showing an association between AD use and breast and ovarian cancer. The possibility that ADs may exhibit a bi-phasic effect, whereby short-term use and/or low dose antidepressants may increase the risk of breast and ovarian cancer, warrants further investigation. Industry affiliations were significantly associated with negative conclusions regarding cancer risk. The findings have implications in light of the 2009 USPSTF guidelines for breast cancer screening and for the informed consent process

    3D Mapping of the SPRY2 Domain of Ryanodine Receptor 1 by Single-Particle Cryo-EM

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    The type 1 skeletal muscle ryanodine receptor (RyR1) is principally responsible for Ca2+ release from the sarcoplasmic reticulum and for the subsequent muscle contraction. The RyR1 contains three SPRY domains. SPRY domains are generally known to mediate protein-protein interactions, however the location of the three SPRY domains in the 3D structure of the RyR1 is not known. Combining immunolabeling and single-particle cryo-electron microscopy we have mapped the SPRY2 domain (S1085-V1208) in the 3D structure of RyR1 using three different antibodies against the SPRY2 domain. Two obstacles for the image processing procedure; limited amount of data and signal dilution introduced by the multiple orientations of the antibody bound in the tetrameric RyR1, were overcome by modifying the 3D reconstruction scheme. This approach enabled us to ascertain that the three antibodies bind to the same region, to obtain a 3D reconstruction of RyR1 with the antibody bound, and to map SPRY2 to the periphery of the cytoplasmic domain of RyR1. We report here the first 3D localization of a SPRY2 domain in any known RyR isoform

    Effect of Native American ancestry on iron-related phenotypes of Alabama hemochromatosis probands with HFE C282Y homozygosity

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    BACKGROUND: In age-matched cohorts of screening study participants recruited from primary care clinics, mean serum transferrin saturation values were significantly lower and mean serum ferritin concentrations were significantly higher in Native Americans than in whites. Twenty-eight percent of 80 Alabama white hemochromatosis probands with HFE C282Y homozygosity previously reported having Native American ancestry, but the possible effect of this ancestry on hemochromatosis phenotypes was unknown. METHODS: We compiled observations in these 80 probands and used univariate and multivariate methods to analyze associations of age, sex, Native American ancestry (as a dichotomous variable), report of ethanol consumption (as a dichotomous variable), percentage transferrin saturation and log(e )serum ferritin concentration at diagnosis, quantities of iron removed by phlebotomy to achieve iron depletion, and quantities of excess iron removed by phlebotomy. RESULTS: In a univariate analysis in which probands were grouped by sex, there were no significant differences in reports of ethanol consumption, transferrin saturation, log(e )serum ferritin concentration, quantities of iron removed to achieve iron depletion, and quantities of excess iron removed by phlebotomy in probands who reported Native American ancestry than in those who did not. In multivariate analyses, transferrin saturation (as a dependent variable) was not significantly associated with any of the available variables, including reports of Native American ancestry and ethanol consumption. The independent variable quantities of excess iron removed by phlebotomy was significantly associated with log(e )serum ferritin used as a dependent variable (p < 0.0001), but not with reports of Native American ancestry or reports of ethanol consumption. Log(e )serum ferritin was the only independent variable significantly associated with quantities of excess iron removed by phlebotomy used as a dependent variable (p < 0.0001) (p < 0.0001; ANOVA of regression). CONCLUSION: We conclude that the iron-related phenotypes of hemochromatosis probands with HFE C282Y homozygosity are similar in those with and without Native American ancestry reports

    Becoming the best mom that I can: women's experiences of managing depression during pregnancy – a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this constructivist grounded theory study was to develop a theoretical model that explains women's processes of managing diagnosed depression when pregnant.</p> <p>Methods</p> <p>We explored the experiences of 19 women in Ontario who were diagnosed with depression during their pregnancy.</p> <p>Results</p> <p>The model that emerged from the analysis was becoming the best mom that I can. Becoming the best mom that I can explains the complex process of the women's journey as they travel from the depths of despair, where the depression is perceived to threaten their pregnancy and their ability to care for the coming baby, to arrive at knowing the self and being in a better place. In order to reground the self and regain control of their lives, the women had to recognize the problem, overcome shame and embarrassment, identify an understanding healthcare provider, and consider the consequences of the depression and its management. When confronting and confining the threat of depression, the women employed strategies of overcoming barriers, gaining knowledge, and taking control. As a result of counseling, medication, or a combination of both, women felt that they had arrived at a better place.</p> <p>Conclusion</p> <p>For many women, the idea that depression could occur during pregnancy was antithetical to their vision of the pregnant self. The challenge for a pregnant woman who is diagnosed with depression, is that effective care for her may jeopardize her baby's future health. This provides a dilemma for about-to-be parents and their healthcare providers. Improved awareness of depression during pregnancy on the part of healthcare professionals is needed to improve the women's understanding of this disorder and their ability to recognize and seek help with depression should it occur during the prenatal period. Further qualitative research is needed to determine the specific aspects that need to be addressed in such classes.</p
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