592 research outputs found

    Poor caregiver mental health predicts mortality of patients with neurodegenerative disease.

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    Dementia and other neurodegenerative diseases cause profound declines in functioning; thus, many patients require caregivers for assistance with daily living. Patients differ greatly in how long they live after disease onset, with the nature and severity of the disease playing an important role. Caregiving can also be extremely stressful, and many caregivers experience declines in mental health. In this study, we investigated the role that caregiver mental health plays in patient mortality. In 176 patient-caregiver dyads, we found that worse caregiver mental health predicted greater patient mortality even when accounting for key risk factors in patients (i.e., diagnosis, age, sex, dementia severity, and patient mental health). These findings highlight the importance of caring for caregivers as well as patients when attempting to improve patients' lives

    An Autoactive NB-LRR Gene Causes Rht13 Dwarfism in Wheat

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    Semidwarfing genes have greatly increased wheat yields globally, yet the widely used gibberellin (GA)-insensitive genes Rht-B1b and Rht-D1b have disadvantages for seedling emergence. Use of the GA-sensitive semidwarfing gene Rht13 avoids this pleiotropic effect. Here, we show that Rht13 encodes a nucleotide-binding site/leucine-rich repeat (NB-LRR) gene. A point mutation in the semidwarf Rht-B13b allele autoactivates the NB-LRR gene and causes a height reduction comparable with Rht-B1b and Rht-D1b in diverse genetic backgrounds. The autoactive Rht-B13b allele leads to transcriptional up-regulation of pathogenesis-related genes including class III peroxidases associated with cell wall remodeling. Rht13 represents a new class of reduced height (Rht) gene, unlike other Rht genes, which encode components of the GA signaling or metabolic pathways. This discovery opens avenues to use autoactive NB-LRR genes as semidwarfing genes in a range of crop species, and to apply Rht13 in wheat breeding programs using a perfect genetic marker

    A conditional mutation in a wheat (Triticum aestivum L.) gene regulating root morphology

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    Key message: Characterisation and genetic mapping of a key gene defining root morphology in bread wheat. Abstract: Root morphology is central to plants for the efficient uptake up of soil water and mineral nutrients. Here we describe a conditional mutant of hexaploid wheat (Triticum aestivum L.) that when grown in soil with high Ca 2+ develops a larger rhizosheath accompanied with shorter roots than the wild type. In wheat, rhizosheath size is a reliable surrogate for root hair length and this was verified in the mutant which possessed longer root hairs than the wild type when grown in high Ca 2+ soil. We named the mutant Stumpy and showed it to be due to a single semi-dominant mutation. The short root phenotype at high Ca 2+ was due to reduced cellular elongation which might also explain the long root hair phenotype. Analysis of root cell walls showed that the polysaccharide composition of Stumpy roots is remodelled when grown at non-permissive (high) Ca 2+ concentrations. The mutation mapped to chromosome 7B and sequencing of the 7B chromosomes in both wild type and Stumpy identified a candidate gene underlying the Stumpy mutation. As part of the process to determine whether the candidate gene was causative, we identified wheat lines in a Cadenza TILLING population with large rhizosheaths but accompanied with normal root length. This finding illustrates the potential of manipulating the gene to disconnect root length from root hair length as a means of developing wheat lines with improved efficiency of nutrient and water uptake. The Stumpy mutant will be valuable for understanding the mechanisms that regulate root morphology in wheat.</p

    A conditional mutation in a wheat (Triticum aestivum L.) gene regulating root morphology

    Get PDF
    Key message: Characterisation and genetic mapping of a key gene defining root morphology in bread wheat. Abstract: Root morphology is central to plants for the efficient uptake up of soil water and mineral nutrients. Here we describe a conditional mutant of hexaploid wheat (Triticum aestivum L.) that when grown in soil with high Ca 2+ develops a larger rhizosheath accompanied with shorter roots than the wild type. In wheat, rhizosheath size is a reliable surrogate for root hair length and this was verified in the mutant which possessed longer root hairs than the wild type when grown in high Ca 2+ soil. We named the mutant Stumpy and showed it to be due to a single semi-dominant mutation. The short root phenotype at high Ca 2+ was due to reduced cellular elongation which might also explain the long root hair phenotype. Analysis of root cell walls showed that the polysaccharide composition of Stumpy roots is remodelled when grown at non-permissive (high) Ca 2+ concentrations. The mutation mapped to chromosome 7B and sequencing of the 7B chromosomes in both wild type and Stumpy identified a candidate gene underlying the Stumpy mutation. As part of the process to determine whether the candidate gene was causative, we identified wheat lines in a Cadenza TILLING population with large rhizosheaths but accompanied with normal root length. This finding illustrates the potential of manipulating the gene to disconnect root length from root hair length as a means of developing wheat lines with improved efficiency of nutrient and water uptake. The Stumpy mutant will be valuable for understanding the mechanisms that regulate root morphology in wheat.</p

    LH-Independent Testosterone Secretion Is Mediated by the Interaction Between GNRH2 and Its Receptor Within Porcine Testes

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    Unlike classic gonadotropin-releasing hormone 1 (GNRH1), the second mammalian isoform (GNRH2) is an ineffective stimulant of gonadotropin release. Species that produce GNRH2 may not maintain a functional GNRH2 receptor (GNRHR2) due to coding errors. A full-length GNRHR2 gene has been identified in swine, but its role in reproduction requires further elucidation. Our objective was to examine the role of GNRH2 and GNRHR2 in testicular function of boars. We discovered that GNRH2 levels were higher in the testis than in the anterior pituitary gland or hypothalamus, corresponding to greater GNRHR2 abundance in the testis versus the anterior pituitary gland. Moreover, GNRH2 immunostaining was most prevalent within seminiferous tubules, whereas GNRHR2 was detected in high abundance on Leydig cells. GNRH2 pretreatment of testis explant cultures elicited testosterone secretion similar to that of human chorionic gonadotropin stimulation. Treatment of mature boars with GNRH2 elevated testosterone levels similar to those of GNRH1-treated males, despite minimal GNRH2-induced release of luteinizing hormone (LH). When pretreated with a GNRHR1 antagonist (SB-75), subsequent GNRH2 treatment stimulated low levels of testosterone secretion despite a pattern of LH release similar to that in the previous trial, suggesting that SB-75 inhibited testicular GNRHR2s. Given that pigs lack testicular GNRHR1, these data may indicate that GNRH2 and its receptor are involved in autocrine or paracrine regulation of testosterone secretion. Notably, our data are the first to suggest a biological function of a novel GNRH2-GNRHR2 system in the testes of swine

    Distinguishing the Impacts of Inadequate Prey and Vessel Traffic on an Endangered Killer Whale (Orcinus orca) Population

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    Managing endangered species often involves evaluating the relative impacts of multiple anthropogenic and ecological pressures. This challenge is particularly formidable for cetaceans, which spend the majority of their time underwater. Noninvasive physiological approaches can be especially informative in this regard. We used a combination of fecal thyroid (T3) and glucocorticoid (GC) hormone measures to assess two threats influencing the endangered southern resident killer whales (SRKW; Orcinus orca) that frequent the inland waters of British Columbia, Canada and Washington, U.S.A. Glucocorticoids increase in response to nutritional and psychological stress, whereas thyroid hormone declines in response to nutritional stress but is unaffected by psychological stress. The inadequate prey hypothesis argues that the killer whales have become prey limited due to reductions of their dominant prey, Chinook salmon (Oncorhynchus tshawytscha). The vessel impact hypothesis argues that high numbers of vessels in close proximity to the whales cause disturbance via psychological stress and/or impaired foraging ability. The GC and T3 measures supported the inadequate prey hypothesis. In particular, GC concentrations were negatively correlated with short-term changes in prey availability. Whereas, T3 concentrations varied by date and year in a manner that corresponded with more long-term prey availability. Physiological correlations with prey overshadowed any impacts of vessels since GCs were lowest during the peak in vessel abundance, which also coincided with the peak in salmon availability. Our results suggest that identification and recovery of strategic salmon populations in the SRKW diet are important to effectively promote SRKW recovery

    When to start antiretroviral therapy in resource-limited settings: a human rights analysis

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    <p>Abstract</p> <p>Background</p> <p>Recent evidence from developed and developing countries shows clear clinical and public health benefit to starting antiretroviral therapy (ART) earlier. While discussions about when to start ART have often focused on the clinical risks and benefits, the main issue is one of fair limit-setting. We applied a human rights framework to assess a policy of early treatment initiation according to the following criteria: public-health purpose; likely effectiveness; specificity; human rights burdens and benefits; potential for less restrictive approaches; and fair administration.</p> <p>Discussion</p> <p>According to our analysis, a policy of earlier ART initiation would better serve both public health and human rights objectives. We highlight a number of policy approaches that could be taken to help meet this aim, including increased international financial support, alternative models of care, and policies to secure the most affordable sources of appropriate antiretroviral drugs.</p> <p>Summary</p> <p>Widespread implementation of earlier ART initiation is challenging in resource-limited settings. Nevertheless, rationing of essential medicines is a restriction of human rights, and the principle of least restriction serves to focus attention on alternative measures such as adapting health service models to increase capacity, decreasing costs, and seeking additional international funding. Progressive realisation using well-defined steps will be necessary to allow for a phased implementation as part of a framework of short-term targets towards nationwide policy adoption, and will require international technical and financial support.</p

    Risk of organism acquisition from prior room occupants: An updated systematic review

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    Background Evidence from a previous systematic review indicates that patients admitted to a room where the previous occupant had a multidrug-resistant bacterial infection resulted in an increased risk of subsequent colonisation and infection with the same organism for the next room occupant. In this paper, we have sought to expand and update this review. Methods A systematic review and meta-analysis was undertaken. A search using Medline/PubMed, Cochrane and CINHAL databases was conducted. Risk of bias was assessed by the ROB-2 tool for randomised control studies and ROBIN-I for non-randomised studies. Results From 5175 identified, 12 papers from 11 studies were included in the review for analysis. From 28,299 patients who were admitted into a room where the prior room occupant had any of the organisms of interest, 651 (2.3%) were shown to acquire the same species of organism. In contrast, 981,865 patients were admitted to a room where the prior occupant did not have an organism of interest, 3818 (0.39%) acquired an organism(s). The pooled acquisition odds ratio (OR) for all the organisms across all studies was 2.45 (95% CI: 1.53–3.93]. There was heterogeneity between the studies (I2 89%, P < 0.001). Conclusion The pooled OR for all the pathogens in this latest review has increased since the original review. Findings from our review provide some evidence to help inform a risk management approach when determining patient room allocation. The risk of pathogen acquisition appears to remain high, supporting the need for continued investment in this area
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