10 research outputs found

    Characterisation of Bidor Kaolinite and Illite

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    Two types of commercial clay minerals from the Bidor region of Perak were studied. From the X-ray diffraction study, these clays were identified as disordered kaolinite and 2 M polymorph of illite. The morphologies, the surface properties, the pore structures and the infrared absorption properties were examined. The basis for the identification of these clays is discussed

    Determinants of male reproductive health disorders: the Men in Australia Telephone Survey (MATeS)

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    Background: The relationship between reproductive health disorders and lifestyle factors in middle-aged and older men is not clear. The aim of this study is to describe lifestyle and biomedical associations as possible causes of erectile dysfunction (ED), prostate disease (PD), lower urinary tract symptoms (LUTS) and perceived symptoms of androgen deficiency (pAD) in a representative population of middle-aged and older men, using the Men in Australia Telephone Survey (MATeS). Methods: A representative sample (n = 5990) of men aged 40+ years, stratified by age and State, was contacted by random selection of households, with an individual response rate of 78%. All men participated in a 20-minute computer-assisted telephone interview exploring general and reproductive health. Associations between male reproductive health disorders and lifestyle and biomedical factors were analysed using multivariate logistic regression (odds ratio [95% confidence interval]). Variables studied included age, body mass index, waist circumference, smoking, alcohol consumption, physical activity, co-morbid disease and medication use for hypertension, high cholesterol and symptoms of depression. Results: Controlling for age and a range of lifestyle and co-morbid exposures, sedentary lifestyle and being underweight was associated with an increased likelihood of ED (1.4 [1.1-1.8]; 2.9 [1.5-5.8], respectively) and pAD (1.3 [1.1-1.7]; 2.7 [1.4-5.0], respectively. Diabetes and cardiovascular disease were both associated with ED, with hypertension strongly associated with LUTS and pAD. Current smoking (inverse association) and depressive symptomatology were the only variables independently associated with PD. All reproductive disorders showed consistent associations with depression (measured either by depressive symptomatology or medication use) in both age-adjusted and multivariate analyses. Conclusion: A range of lifestyle factors, more often associated with chronic disease, were significantly associated with male reproductive health disorders. Education strategies directed to improving general health may also confer benefits to male reproductive health.Carol A. Holden, Robert I. McLachlan, Marian Pitts, Robert Cumming, Gary Wittert, Johnathon P. Ehsani, David M. de Kretser, David J. Handelsma

    Associations between weight change and biomarkers of cardiometabolic risk in South Asians:secondary analyses of the PODOSA trial

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    Background/Objectives: The association of weight changes with cardiometabolic biomarkers in South Asians has been sparsely studied. Subjects/Methods: We measured cardiometabolic biomarkers at baseline and after 3 years in the Prevention of Diabetes and Obesity in South Asians Trial. We investigated the effect of a lifestyle intervention on biomarkers in the randomized groups. In addition, treating the population as a single cohort, we estimated the association between change in weight and change in biomarkers. Results: Complete data were available at baseline and after 3 years in 151 participants. At 3 years, there was an adjusted mean reduction of 1·44 kg (95% confidence interval (95% CI): 0.18–2.71) in weight and 1.59 cm (95% CI: 0.08–3.09) in waist circumference in the intervention arm as compared with the control arm. There was no clear evidence of difference between the intervention and control arms in change of mean value of any biomarker. As a single cohort, every 1 kg weight reduction during follow-up was associated with a reduction in triglycerides (−1.3%, P=0.048), alanine aminotransferase (−2.5%, P=0.032), gamma-glutamyl transferase (−2.2%, P=0.040), leptin (−6.5%, P<0.0001), insulin (−3.7%, P=0.0005), fasting glucose (−0.8%, P=0.0071), 2-h glucose (−2.3%, P=0.0002) and Homeostatic Model Assessment of insulin resistance (HOMA-IR: −4.5%, P=0.0002). There was no evidence of associations with other lipid measures, tissue plasminogen activator, markers of inflammation or blood pressure. Conclusions: We demonstrate that modest weight decrease in SAs is associated with improvements in markers of total and ectopic fat as well as insulin resistance and glycaemia in South Asians at risk of diabetes. Future trials with more intensive weight change are needed to extend these findings

    Genetic mechanisms of critical illness in COVID-19.

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    Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice

    Relationships between resistance to cross-linking agents and glutathione metabolism, aldehyde dehydrogenase isozymes and adenovirus replication in human tumour cell lines

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    In a panel of 10 human tumour cell lines with no prior exposure to drugs in vitro, resistance to cisplatin correlated with resistance to the nitrogen mustard derivatives Asta Z-7557 (mafosfamide, an activated form of cyclophosphamide), melphalan and chlorambucil. Simultaneous treatment with dl-buthionine-S,R-sulfoximine did not enhance the toxicity of cisplatin or Asta Z-7557, and no correlation was found between drug resistance and cellular levels of metallothioneins (as judged by sensitivity to cadmium chloride), glutathione (GSH), GSH reductase, GSH transferase, or γ-glutamyltranspeptidase. The two cell lines most resistant to Asta Z-7557 expressed aldehyde dehydrogenase cytosolic isozyme 1, found also in normal ovary, but not isozyme 3. Treatment of resistant cells with cisplatin or Asta Z-7557 inhibited cellular DNA synthesis and replication of adenovirus 5 to a lesser extent than in sensitive cells. The virus could be directly inactivated by both drugs prior to infection, subsequent replication being inhibited to the same extent in sensitive and resistant cells. In contrast to Asta Z-7557 and other DNA damaging agents, cisplatin was much more toxic to adenovirus (d 0.022-0.048 μM) than to cells (d 0.25-2.5 μM). The adenovirus 5 mutant Ad5ts125 having a G → A substitution was even more sensitive to cisplatin (d 7-8 nM) than wild type virus and another mutant. Cisplatin was detoxified less by sonicated resistant cells than sensitive cells, as judged by inactivation of Ad5ts125 added to the reaction mixture. It can be inferred that (i) the major differences in cellular resistance to cisplatin and Asta Z-7557 in the present material did not involve enhanced DNA repair or protection by metallothioneins or GSH, but were associated with the ability to continue cellular and viral DNA synthesis during treatment, (ii) resistance was not associated with less template damage, and (iii) the adenovirus genome may be a suitable probe for predicting tumour resistance to cisplatin and for elucidating the DNA sequence dependence of cisplatin toxicity

    Mapping the human genetic architecture of COVID-19

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    The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3–7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease

    Mapping the human genetic architecture of COVID-19

    Get PDF
    The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3,4,5,6,7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease
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