77 research outputs found

    Comparative inhibition by substrate analogues 3-methoxy- and 3-hydroxydesaminokynurenine and an improved 3 step purification of recombinant human kynureninase.

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    BACKGROUND: Kynureninase is a key enzyme on the kynurenine pathway of tryptophan metabolism. One of the end products of the pathway is the neurotoxin quinolinic acid which appears to be responsible for neuronal cell death in a number of important neurological diseases. This makes kynureninase a possible therapeutic target for diseases such as Huntington's, Alzheimer's and AIDS related dementia, and the development of potent inhibitors an important research aim. RESULTS: Two new kynurenine analogues, 3-hydroxydesaminokynurenine and 3-methoxydesaminokynurenine, were synthesised as inhibitors of kynureninase and tested on the tryptophan-induced bacterial enzyme from Pseudomonas fluorescens, the recombinant human enzyme and the rat hepatic enzyme. They were found to be mixed inhibitors of all three enzymes displaying both competitive and non competitive inhibition. The 3-hydroxy derivative gave low K(i )values of 5, 40 and 100 nM respectively. An improved 3-step purification scheme for recombinant human kynureninase was also developed. CONCLUSION: For kynureninase from all three species the 2-amino group was found to be crucial for activity whilst the 3-hydroxyl group played a fundamental role in binding at the active site presumably via hydrogen bonding. The potency of the various inhibitors was found to be species specific. The 3-hydroxylated inhibitor had a greater affinity for the human enzyme, consistent with its specificity for 3-hydroxykynurenine as substrate, whilst the methoxylated version yielded no significant difference between bacterial and human kynureninase. The modified purification described is relatively quick, simple and cost effective

    Evaluation of NSW Community-based Mental Health Programs: Community Living Supports and Housing and Accommodation Support Initiative. CLS-HASI Evaluation Report

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    The Community Living Supports (CLS) and Housing and Accommodation Support Initiative (HASI) are community-based programs that support people with severe mental illness to live and participate in the community, the way that they want to. The programs offer psychosocial support, tenancy support and, where appropriate, clinical mental health services. Many consumers are also supported to access secure housing. CLS-HASI are statewide programs funded by the NSW Ministry of Health (Ministry) and delivered locally through partnerships between local health district (LHD) mental health services and specialist mental health Community Managed Organisations (CMOs). The programs also have a strong partnership with the NSW Department of Communities and Justice (DCJ) and community housing providers for social housing. The Ministry commissioned the Social Policy Research Centre (SPRC) to evaluate the CLS-HASI programs. The evaluation involved two rounds of qualitative interviews and focus groups, as well as the analysis of quantitative program data and statewide outcomes data about consumers. It ran from November 2017 to January 2020. CLS-HASI supported 5,533 consumers in the study period from 2015 to 2019. Most consumers were in the programs for only part of this period. The average time in CLS-HASI was 10.7 months. Overall, the evaluation shows that CLS-HASI is generally working well, achieving its goals and is cost effective. At a broad summary level: • Consumers liked the programs, and most experienced positive outcomes – overall the programs improved wellbeing, helped people better manage their mental health, enhanced aspects of consumers’ physical health and increased opportunities for social inclusion. • Consumer contact with community mental health services decreased by 10% in the first year in CLS-HASI and was 63.7% less if they remained in the programs for more than one year. • Hospital admissions due to mental health decreased by 74% following program entry, and the average length of stay decreased by 74.8% over two years. This improvement was sustained after consumers exited the programs. • Consumers with a new charge in the criminal justice system and with community corrections orders dropped to almost zero in the year after program entry

    ω-3 Polyunsaturated fatty acids prevent pressure overload-induced ventricular dilation and decrease in mitochondrial enzymes despite no change in adiponectin

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    <p>Abstract</p> <p>Background</p> <p>Pathological left ventricular (LV) hypertrophy frequently progresses to dilated heart failure with suppressed mitochondrial oxidative capacity. Dietary marine ω-3 polyunsaturated fatty acids (ω-3 PUFA) up-regulate adiponectin and prevent LV dilation in rats subjected to pressure overload. This study 1) assessed the effects of ω-3 PUFA on LV dilation and down-regulation of mitochondrial enzymes in response to pressure overload; and 2) evaluated the role of adiponectin in mediating the effects of ω-3 PUFA in heart.</p> <p>Methods</p> <p>Wild type (WT) and adiponectin-/- mice underwent transverse aortic constriction (TAC) and were fed standard chow ± ω-3 PUFA for 6 weeks. At 6 weeks, echocardiography was performed to assess LV function, mice were terminated, and mitochondrial enzyme activities were evaluated.</p> <p>Results</p> <p>TAC induced similar pathological LV hypertrophy compared to sham mice in both strains on both diets. In WT mice TAC increased LV systolic and diastolic volumes and reduced mitochondrial enzyme activities, which were attenuated by ω-3 PUFA without increasing adiponectin. In contrast, adiponectin-/- mice displayed no increase in LV end diastolic and systolic volumes or decrease in mitochondrial enzymes with TAC, and did not respond to ω-3 PUFA.</p> <p>Conclusion</p> <p>These findings suggest ω-3 PUFA attenuates cardiac pathology in response to pressure overload independent of an elevation in adiponectin.</p

    Improved Mitochondrial Function with Diet-Induced Increase in Either Docosahexaenoic Acid or Arachidonic Acid in Membrane Phospholipids

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    Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP). We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA; 22:6n3) and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6) in mitochondrial membranes is associated with a greater Ca2+ load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6). Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca2+-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca2+ load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs

    The Relationship of Maternal Prepregnancy Body Mass Index and Pregnancy Weight Gain to Neurocognitive Function at Age 10 Years among Children Born Extremely Preterm

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    OBJECTIVE: To assess the association between maternal prepregnancy body mass index and adequacy of pregnancy weight gain in relation to neurocognitive function in school-aged children born extremely preterm. STUDY DESIGN: Study participants were 535 ten-year-old children enrolled previously in the prospective multicenter Extremely Low Gestational Age Newborns cohort study who were products of singleton pregnancies. Soon after delivery, mothers provided information about prepregnancy weight. Prepregnancy body mass index and adequacy of weight gain were characterized based on this information. Children underwent a neurocognitive evaluation at 10 years of age. RESULTS: Maternal prepregnancy obesity was associated with increased odds of a lower score for Differential Ability Scales-II Verbal IQ, for Developmental Neuropsychological Assessment-II measures of processing speed and visual fine motor control, and for Wechsler Individual Achievement Test-III Spelling. Children born to mothers who gained an excessive amount of weight were at increased odds of a low score on the Oral and Written Language Scales Oral Expression assessment. Conversely, children whose mother did not gain an adequate amount of weight were at increased odds of a lower score on the Oral and Written Language Scales Oral Expression and Wechsler Individual Achievement Test-III Word Reading assessments. CONCLUSION: In this cohort of infants born extremely preterm, maternal obesity was associated with poorer performance on some assessments of neurocognitive function. Our findings are consistent with the observational and experimental literature and suggest that opportunities may exist to mitigate risk through education and behavioral intervention before pregnancy

    Linkage of Type I Interferon Activity and TNF-Alpha Levels in Serum with Sarcoidosis Manifestations and Ancestry

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    BACKGROUND: Both type I interferon (IFN), also known as IFN-α and tumor necrosis factor alpha (TNF-α) have been implicated in the pathogenesis of sarcoidosis. We investigated serum levels of these cytokines in a large multi-ancestral sarcoidosis population to determine correlations between cytokine levels and disease phenotypes. METHODS: We studied serum samples from 98 patients with sarcoidosis, including 71 patients of African-American ancestry and 27 patients of European-American ancestry. Serum type I IFN was measured using a sensitive reporter cell assay and serum TNF-α was measured using a commercial ELISA kit. Clinical data including presence or absence of neurologic, cardiac, and severe pulmonary manifestations of sarcoidosis were abstracted from medical records. Twenty age-matched non-autoimmune controls were also studied from each ancestral background. Differences in cytokine levels between groups were analyzed with Mann-Whitney U test, and correlations were assessed using Spearman's rho. Multivariate logistic regression models were used to detect associations between cytokines and clinical manifestations. RESULTS: Significant differences in cytokine levels were observed between African- and European-American patients with sarcoidosis. In African-Americans, serum TNF-α levels were significantly higher relative to matched controls (P = 0.039), and patients with neurologic disease had significantly higher TNF-α than patients lacking this manifestation (P = 0.022). In European-Americans, serum type I IFN activity was higher in sarcoidosis cases as compared to matched controls, and patients with extra-pulmonary disease represented a high serum IFN subgroup (P = 0.0032). None of the associations observed were shared between the two ancestral groups. CONCLUSIONS: Our data indicate that significant associations between serum levels of TNF-α and type I IFN and clinical manifestations exist in a sarcoidosis cohort that differ significantly by self-reported ancestry. In each ancestral background, the cytokine elevated in patients with sarcoidosis was also associated with a particular disease phenotype. These findings may relate to ancestral differences in the molecular pathogenesis of this heterogeneous disease

    Creative destruction in science

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    Drawing on the concept of a gale of creative destruction in a capitalistic economy, we argue that initiatives to assess the robustness of findings in the organizational literature should aim to simultaneously test competing ideas operating in the same theoretical space. In other words, replication efforts should seek not just to support or question the original findings, but also to replace them with revised, stronger theories with greater explanatory power. Achieving this will typically require adding new measures, conditions, and subject populations to research designs, in order to carry out conceptual tests of multiple theories in addition to directly replicating the original findings. To illustrate the value of the creative destruction approach for theory pruning in organizational scholarship, we describe recent replication initiatives re-examining culture and work morality, working parents\u2019 reasoning about day care options, and gender discrimination in hiring decisions. Significance statement It is becoming increasingly clear that many, if not most, published research findings across scientific fields are not readily replicable when the same method is repeated. Although extremely valuable, failed replications risk leaving a theoretical void\u2014 reducing confidence the original theoretical prediction is true, but not replacing it with positive evidence in favor of an alternative theory. We introduce the creative destruction approach to replication, which combines theory pruning methods from the field of management with emerging best practices from the open science movement, with the aim of making replications as generative as possible. In effect, we advocate for a Replication 2.0 movement in which the goal shifts from checking on the reliability of past findings to actively engaging in competitive theory testing and theory building. Scientific transparency statement The materials, code, and data for this article are posted publicly on the Open Science Framework, with links provided in the article

    Prevalence and architecture of de novo mutations in developmental disorders.

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    The genomes of individuals with severe, undiagnosed developmental disorders are enriched in damaging de novo mutations (DNMs) in developmentally important genes. Here we have sequenced the exomes of 4,293 families containing individuals with developmental disorders, and meta-analysed these data with data from another 3,287 individuals with similar disorders. We show that the most important factors influencing the diagnostic yield of DNMs are the sex of the affected individual, the relatedness of their parents, whether close relatives are affected and the parental ages. We identified 94 genes enriched in damaging DNMs, including 14 that previously lacked compelling evidence of involvement in developmental disorders. We have also characterized the phenotypic diversity among these disorders. We estimate that 42% of our cohort carry pathogenic DNMs in coding sequences; approximately half of these DNMs disrupt gene function and the remainder result in altered protein function. We estimate that developmental disorders caused by DNMs have an average prevalence of 1 in 213 to 1 in 448 births, depending on parental age. Given current global demographics, this equates to almost 400,000 children born per year

    Extremely low gestational age and very low birthweight for gestational age are risk factors for autism spectrum disorder in a large cohort study of 10-year-old children born at 23-27 weeks’ gestation

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    No prospective cohort study of high-risk children has used rigorous exposure assessment and optimal diagnostic procedures to examine the perinatal antecedents of autism spectrum disorder (ASD), separately among those with and without cognitive impairment
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