294 research outputs found

    Siderastrea siderea Spawning and Oocyte Resorption at High Latitude

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    At high latitudes (\u3e25°), sexual reproduction and the maintenance of coral populations can be impaired by marginal environmental conditions. However, little is known about sexual reproduction of many coral species at high latitude on the northern-most extension of the Florida Reef Tract. This study aimed to histologically characterize the reproductive ecology of Siderastrea siderea, near Fort Lauderdale, Florida (26°N). Tissue samples of S. siderea were collected semi-monthly to multiweekly from August to November in 2007 and 2008. Spawning was inferred from gametogenesis and oocyte resorption was observed in detail. Environmental variables including temperature and lunar cycle were examined for relationship with potential spawning times. Based on the histological evidence, we infer that spawning likely occurred primarily in October. Gametogenesis in this species is likely mediated by seasonal temperature variation, whereas lunar cycle could act as finer scale environmental cue for coordination of spawning. Our findings highlight that S. siderea spawning occurs later in the year compared to other populations of this species throughout the Caribbean and to other coral species near Fort Lauderdale. For the first time, oocyte resorption stages are described and constitute a baseline for future projects that aim to understand this process in corals

    Scleractinian Coral Recruitment to Reefs Physically Damaged by Ship Groundings

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    The southeast Florida reef system faces a number of stress factors, among which ship groundings are one of the most physically damaging. Portions of the Florida reef tract located near Port Everglades, Broward County, Florida, USA have been damaged by ship groundings. In 2004, physical damage of more than 30,000 m2 was caused by the groundings of two large cargo ships, the MV Eastwind and MV Federal Pescadores. The present study was designed to measure differences of scleractinian coral recruitment patterns (recruit diversity and richness) and rates to these injured sites in comparison to undamaged reef sites. Coral recruitment rates were measured on unglazed ceramic tiles deployed for a period of one year from February 2007 to February 2008 at five different locations: three control sites (including a high coral cover site), and the two ship grounding sites. Morphology and genetic markers including CO1 and cytb were used to identify the coral recruits. A whole genome amplification kit (REPLI-g, Qiagen) was used to obtain sufficient amounts of DNA. Results revealed low recruitment rates (0.5-2.7 recruitsm-2 yr-1) to the studied sites, suggesting a low potential for recovery of the damaged areas

    Fecundity and Sexual Maturity of the Coral Siderastrea siderea at High Latitude Along the Florida Reef Tract, USA

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    Siderastrea siderea is one of the most abundant corals at high latitude shallow sites along the Florida Reef Tract (25°–27°N). This species is able to tolerate wide seawater temperature fluctuations and sedimentation stress, but its reproductive status at high latitudes and under marginal environmental conditions is poorly understood. The objectives of this study were to evaluate the reproductive potential of S. siderea along a latitudinal gradient (25°–27°N) and to determine if sexual maturity occurs in small (\u3c12.0 cm) S. siderea colonies. Samples of coral tissue were collected in 2007, 2008, and 2009 at three sites along the latitudinal gradient and were processed for histological analysis. Oocyte size, volume, and abundance were used to calculate fecundity. Results showed that fecundity decreased with increasing latitude and that oocyte volume was the major contributing factor to this variation. Mature oocytes were observed in S. siderea colonies at sizes as small as 1.1 cm in diameter. The ability of S. siderea to reach fertility at high latitude areas suggests this species is able to reproduce under marginal environmental conditions; however, reduction in oocyte size could increase local retention of larvae. The presence of mature oocytes in small colonies suggests that stress can reduce somatic growth and shift sexual maturity to smaller colony sizes

    Disenfranchised grievers - The GP's role in management

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    Copyright © 2007 The Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.Disenfranchised grief results from a loss that is not or cannot be openly acknowledged, publicly mourned, or socially supported. This article aims to explain the concept and varying presentations of disenfranchised grief and outlines the importance of the general practitioner's role. Preliminary quantitative results of a study of 15 cross cultural workers re-entering Australia are presented, showing more than half experiencing grief during re-entry and all having some form of disenfranchised grief. Disenfranchised grievers present with various symptoms, however, primary care has focused on mental illness, with little recognition of loss and grief issues, especially disenfranchised grief. Further research is required and currently underway to design and formally test a model that can be implemented within an Australian fee-for-service setting.Susan Selby, Alison Jones, Teresa Burgess, Sheila Clark, Nicole Moulding, Justin Beilb

    The cell adhesion molecule L1 regulates the expression of choline acetyltransferase and the development of septal cholinergic neurons

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    Mutations in the L1 gene cause severe brain malformations and mental retardation. We investigated the potential roles of L1 in the regulation of choline acetyltransferase (ChAT) and in the development of septal cholinergic neurons, which are known to project to the hippocampus and play key roles in cognitive functions. Using stereological approaches, we detected significantly fewer ChAT-positive cholinergic neurons in the medial septum and vertical limb of the diagonal band of Broca (MS/VDB) of 2-week-old L1-deficient mice compared to wild-type littermates (1644 ± 137 vs. 2051 ± 165, P = 0.038). ChAT protein levels in the septum were 53% lower in 2-week-old L1-deficient mice compared to wild-type littermates. ChAT activity in the septum was significantly reduced in L1-deficient mice compared to wild-type littermates at 1 (34%) and 2 (40%) weeks of age. In vitro, increasing doses of L1-Fc induced ChAT activity in septal neurons with a significant linear trend (*P = 0.0065). At 4 weeks of age in the septum and at all time points investigated in the caudate-putamen (CPu), the number of ChAT-positive neurons and the levels of ChAT activity were not statistically different between L1-deficient mice and wild-type littermates. The total number of cells positive for the neuronal nuclear antigen (NeuN) in the MS/VDB and CPu was not statistically different in L1-deficient mice compared to wild-type littermates, and comparable expression of the cell cycle marker Ki67 was observed. Our results indicate that L1 is required for the timely maturation of septal cholinergic neurons and that L1 promotes the expression and activity of ChAT in septal neurons

    Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung

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    Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation

    Effective Caspase Inhibition Blocks Neutrophil Apoptosis and Reveals Mcl-1 as Both a Regulator and a Target of Neutrophil Caspase Activation

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    Human tissue inflammation is terminated, at least in part, by the death of inflammatory neutrophils by apoptosis. The regulation of this process is therefore key to understanding and manipulating inflammation resolution. Previous data have suggested that the short-lived pro-survival Bcl-2 family protein, Mcl-1, is instrumental in determining neutrophil lifespan. However, Mcl-1 can be cleaved following caspase activity, and the possibility therefore remains that the observed fall in Mcl-1 levels is due to caspase activity downstream of caspase activation, rather than being a key event initiating apoptosis in human neutrophils

    Does psychological status influence clinical outcomes in patients with inflammatory bowel disease (IBD) and other chronic gastroenterological diseases: An observational cohort prospective study

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    Background: Whether there is a temporal relationship between psychological problems and clinical outcomes in patients with diseases of the digestive tract has not been widely researched. Thus, our aims were 1) To observe and compare prospectively clinical outcomes in relation to psychological co-morbidity in patients with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and chronic hepatitis C (HCV) and, 2) To test the hypothesis that patients with psychological co-morbidities are less likely to have a satisfactory response to standard treatment at 12 months. Methods: Overall, 139 patients were enrolled in this observational cohort prospective study. Over the ensuing year, physical and psychological measures were made at baseline and after 12 months (HADS, SCL90, SF-12 and disease activity measures). A logistic regression was conducted to observe any relationship between baseline characteristics and patients' clinical outcomes after 12 months. Results: Overall, there was no relationship between psychological status and quality of life at baseline and relapse at 12 months (p > 0.05). However, patients with inactive disease at baseline were at lower risk of relapse after 12 months (OR = 0.046, CI: 0.012–0.178). No significant relationship was found between psychological problems such as depression/anxiety and a total number of relapses in the IBD group. However, interestingly, patients with an active disease at baseline tended to have a greater number of relapses (OR = 3.07, CI: 1.650–5.738) and CD participants were found at lower risk of relapse than UC participants (OR = 0.382, CI: 0.198–0.736). Conclusion: In contrast to previous investigations, this study suggests that there is no temporal relationship between psychological problems at baseline and clinical outcomes over time. Longer and larger prospective studies are needed to better understand this result.Antonina A Mikocka-Walus, Deborah A Turnbull, Nicole T Moulding, Ian G Wilson, Gerald J Holtmann and Jane M Andrew

    Screening for latent tuberculosis infection among undocumented immigrants in Swiss healthcare centres; a descriptive exploratory study

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    BACKGROUND: Migration is one of the major causes of tuberculosis in developed countries. Undocumented patients are usually not screened at the border and are not covered by a health insurance increasing their risk of developing the disease unnoticed. Urban health centres could help identify this population at risk. The objective of this study is to assess the prevalence of latent tuberculosis infection (LTBI) and adherence to preventive treatment in a population of undocumented immigrant patients. METHODS: All consecutive undocumented patients that visited two urban healthcare centres for vulnerable populations in Lausanne, Switzerland for the first time were offered tuberculosis screening with an interferon-gamma assay. Preventive treatment was offered if indicated. Adherence to treatment was evaluated monthly over a nine month period. RESULTS: Of the 161 participants, 131 (81.4%) agreed to screening and 125 had complete examinations. Twenty-four of the 125 patients (19.2%; CI95% 12.7;27.2) had positive interferon-gamma assay results, two of which had active tuberculosis. Only five patients with LTBI completed full preventive treatments. Five others initiated the treatment but did not follow through. CONCLUSION: Screening for tuberculosis infection in this hard-to-reach population is feasible in dedicated urban clinics, and the prevalence of LTBI is high in this vulnerable population. However, the low adherence to treatment is an important public health concern, and new strategies are needed to address this problem
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