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Search: WFRF:(Kamel S)

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  • 2017
  • swepub:Mat__t
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  • 2021
  • swepub:Mat__t
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  • Bravo, L, et al. (author)
  • 2021
  • swepub:Mat__t
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  • Tabiri, S, et al. (author)
  • 2021
  • swepub:Mat__t
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  • Khatri, C, et al. (author)
  • Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study
  • 2021
  • In: BMJ open. - : BMJ. - 2044-6055. ; 11:11, s. e050830-
  • Journal article (peer-reviewed)abstract
    • Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis.SettingProspective, international, multicentre, observational cohort study.ParticipantsPatients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative).Primary outcome30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality.ResultsThis study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p<0.001), age >80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787).ConclusionsPatients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups.Trial registration numberNCT04323644
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  • Veer, IM, et al. (author)
  • Psycho-social factors associated with mental resilience in the Corona lockdown
  • 2021
  • In: Translational psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11:1, s. 67-
  • Journal article (peer-reviewed)abstract
    • The SARS-CoV-2 pandemic is not only a threat to physical health but is also having severe impacts on mental health. Although increases in stress-related symptomatology and other adverse psycho-social outcomes, as well as their most important risk factors have been described, hardly anything is known about potential protective factors. Resilience refers to the maintenance of mental health despite adversity. To gain mechanistic insights about the relationship between described psycho-social resilience factors and resilience specifically in the current crisis, we assessed resilience factors, exposure to Corona crisis-specific and general stressors, as well as internalizing symptoms in a cross-sectional online survey conducted in 24 languages during the most intense phase of the lockdown in Europe (22 March to 19 April) in a convenience sample of N = 15,970 adults. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience (p < 0.0001). The resilience factor PAS also partly mediated the positive association between perceived social support and resilience, and its association with resilience was in turn partly mediated by the ability to easily recover from stress (both p < 0.0001). In comparison with other resilience factors, good stress response recovery and positive appraisal specifically of the consequences of the Corona crisis were the strongest factors. Preregistered exploratory subgroup analyses (osf.io/thka9) showed that all tested resilience factors generalize across major socio-demographic categories. This research identifies modifiable protective factors that can be targeted by public mental health efforts in this and in future pandemics.
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15.
  • Freedman, Ben, et al. (author)
  • Screening for Atrial Fibrillation A Report of the AF-SCREEN International Collaboration
  • 2017
  • In: Circulation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 135:19, s. 1851-
  • Journal article (peer-reviewed)abstract
    • Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country-and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.
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16.
  • van der Meer, PF, et al. (author)
  • Aggregates in platelet concentrates
  • 2015
  • In: Vox sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; 108:1, s. 96-125
  • Journal article (peer-reviewed)
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17.
  • Jayasiri, Subashini C., et al. (author)
  • The Faces of Fungi database: fungal names linked with morphology, phylogeny and human impacts
  • 2015
  • In: Fungal diversity. - : Springer Science and Business Media LLC. - 1560-2745 .- 1878-9129. ; 74:1, s. 3-18
  • Journal article (peer-reviewed)abstract
    • Taxonomic names are key links between various databases that store information on different organisms. Several global fungal nomenclural and taxonomic databases (notably Index Fungorum, Species Fungorum and MycoBank) can be sourced to find taxonomic details about fungi, while DNA sequence data can be sourced from NCBI, EBI and UNITE databases. Although the sequence data may be linked to a name, the quality of the metadata is variable and generally there is no corresponding link to images, descriptions or herbarium material. There is generally no way to establish the accuracy of the names in these genomic databases, other than whether the submission is from a reputable source. To tackle this problem, a new database (FacesofFungi), accessible at www.facesoffungi.org (FoF) has been established. This fungal database allows deposition of taxonomic data, phenotypic details and other useful data, which will enhance our current taxonomic understanding and ultimately enable mycologists to gain better and updated insights into the current fungal classification system. In addition, the database will also allow access to comprehensive metadata including descriptions of voucher and type specimens. This database is user-friendly, providing links and easy access between taxonomic ranks, with the classification system based primarily on molecular data (from the literature and via updated web-based phylogenetic trees), and to a lesser extent on morphological data when molecular data are unavailable. In FoF species are not only linked to the closest phylogenetic representatives, but also relevant data is provided, wherever available, on various applied aspects, such as ecological, industrial, quarantine and chemical uses. The data include the three main fungal groups (Ascomycota, Basidiomycota, Basal fungi) and fungus-like organisms. The FoF webpage is an output funded by the Mushroom Research Foundation which is an NGO with seven directors with mycological expertise. The webpage has 76 curators, and with the help of these specialists, FoF will provide an updated natural classification of the fungi, with illustrated accounts of species linked to molecular data. The present paper introduces the FoF database to the scientific community and briefly reviews some of the problems associated with classification and identification of the main fungal groups. The structure and use of the database is then explained. We would like to invite all mycologists to contribute to these web pages.
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18.
  • Schnabel, Renate B., et al. (author)
  • Searching for Atrial Fibrillation Poststroke : A White Paper of the AF-SCREEN International Collaboration
  • 2019
  • In: Circulation. - 1524-4539. ; 140:22, s. 1834-1850
  • Journal article (peer-reviewed)abstract
    • Cardiac thromboembolism attributed to atrial fibrillation (AF) is responsible for up to one-third of ischemic strokes. Stroke may be the first manifestation of previously undetected AF. Given the efficacy of oral anticoagulants in preventing AF-related ischemic strokes, strategies of searching for AF after a stroke using ECG monitoring followed by oral anticoagulation (OAC) treatment have been proposed to prevent recurrent cardioembolic strokes. This white paper by experts from the AF-SCREEN International Collaboration summarizes existing evidence and knowledge gaps on searching for AF after a stroke by using ECG monitoring. New AF can be detected by routine plus intensive ECG monitoring in approximately one-quarter of patients with ischemic stroke. It may be causal, a bystander, or neurogenically induced by the stroke. AF after a stroke is a risk factor for thromboembolism and a strong marker for atrial myopathy. After acute ischemic stroke, patients should undergo 72 hours of electrocardiographic monitoring to detect AF. The diagnosis requires an ECG of sufficient quality for confirmation by a health professional with ECG rhythm expertise. AF detection rate is a function of monitoring duration and quality of analysis, AF episode definition, interval from stroke to monitoring commencement, and patient characteristics including old age, certain ECG alterations, and stroke type. Markers of atrial myopathy (eg, imaging, atrial ectopy, natriuretic peptides) may increase AF yield from monitoring and could be used to guide patient selection for more intensive/prolonged poststroke ECG monitoring. Atrial myopathy without detected AF is not currently sufficient to initiate OAC. The concept of embolic stroke of unknown source is not proven to identify patients who have had a stroke benefitting from empiric OAC treatment. However, some embolic stroke of unknown source subgroups (eg, advanced age, atrial enlargement) might benefit more from non-vitamin K-dependent OAC therapy than aspirin. Fulfilling embolic stroke of unknown source criteria is an indication neither for empiric non-vitamin K-dependent OAC treatment nor for withholding prolonged ECG monitoring for AF. Clinically diagnosed AF after a stroke or a transient ischemic attack is associated with significantly increased risk of recurrent stroke or systemic embolism, in particular, with additional stroke risk factors, and requires OAC rather than antiplatelet therapy. The minimum subclinical AF duration required on ECG monitoring poststroke/transient ischemic attack to recommend OAC therapy is debated.
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  • Sahin, O, et al. (author)
  • International Multi-Specialty Expert Physician Preoperative Identification of Extranodal Extension n Oropharyngeal Cancer Patients using Computed Tomography: Prospective Blinded Human Inter-Observer Performance Evaluation
  • 2024
  • In: medRxiv : the preprint server for health sciences. - : Cold Spring Harbor Laboratory.
  • Journal article (peer-reviewed)abstract
    • BackgroundExtranodal extension (ENE) is an important adverse prognostic factor in oropharyngeal cancer (OPC) and is often employed in therapeutic decision making. Clinician-based determination of ENE from radiological imaging is a difficult task with high inter-observer variability. However, the role of clinical specialty on the determination of ENE has been unexplored.MethodsPre-therapy computed tomography (CT) images for 24 human papillomavirus-positive (HPV+) OPC patients were selected for the analysis; 6 scans were randomly chosen to be duplicated, resulting in a total of 30 scans of which 21 had pathologically-confirmed ENE. 34 expert clinician annotators, comprised of 11 radiologists, 12 surgeons, and 11 radiation oncologists separately evaluated the 30 CT scans for ENE and noted the presence or absence of specific radiographic criteria and confidence in their prediction. Discriminative performance was measured using accuracy, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and Brier score for each physician. Statistical comparisons of discriminative performance were calculated using Mann Whitney U tests. Significant radiographic factors in correct discrimination of ENE status were determined through a logistic regression analysis. Interobserver agreement was measured using Fleiss’ kappa.ResultsThe median accuracy for ENE discrimination across all specialties was 0.57. There were significant differences between radiologists and surgeons for Brier score (0.33 vs. 0.26), radiation oncologists and surgeons for sensitivity (0.48 vs. 0.69), and radiation oncologists and radiologists/surgeons for specificity (0.89 vs. 0.56). There were no significant differences between specialties for accuracy or AUC. Indistinct capsular contour, nodal necrosis, and nodal matting were significant factors in regression analysis. Fleiss’ kappa was less than 0.6 for all the radiographic criteria, regardless of specialty.ConclusionsDetection of ENE in HPV+OPC patients on CT imaging remains a difficult task with high variability, regardless of clinician specialty. Although some differences do exist between the specialists, they are often minimal. Further research in automated analysis of ENE from radiographic images is likely needed.
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  • Cadrin-Tourigny, Julia, et al. (author)
  • A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy
  • 2019
  • In: European Heart Journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 40:23, s. 1850-1858
  • Journal article (peer-reviewed)abstract
    • AIMS: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. METHODS AND RESULTS: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.6% reduction of ICD placements with the same proportion of protected patients (P < 0.001). CONCLUSION: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).
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  • Cadrin-Tourigny, Julia, et al. (author)
  • A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy
  • 2022
  • In: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 43:32, s. 1-9
  • Journal article (peer-reviewed)abstract
    • Aims: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. Methods and results: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: Age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.3% reduction of ICD placements with the same proportion of protected patients (P < 0.001). Conclusion: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).
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  • Cadrin-Tourigny, Julia, et al. (author)
  • Sudden Cardiac Death Prediction in Arrhythmogenic Right Ventricular Cardiomyopathy : A Multinational Collaboration
  • 2021
  • In: Circulation: Arrhythmia and Electrophysiology. - : Lippincott Williams & Wilkins. - 1941-3149 .- 1941-3084. ; 14:1
  • Journal article (peer-reviewed)abstract
    • Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with ventricular arrhythmias (VA) and sudden cardiac death (SCD). A model was recently developed to predict incident sustained VA in patients with ARVC. However, since this outcome may overestimate the risk for SCD, we aimed to specifically predict life-threatening VA (LTVA) as a closer surrogate for SCD. Methods: We assembled a retrospective cohort of definite ARVC cases from 15 centers in North America and Europe. Association of 8 prespecified clinical predictors with LTVA (SCD, aborted SCD, sustained, or implantable cardioverter-defibrillator treated ventricular tachycardia >250 beats per minute) in follow-up was assessed by Cox regression with backward selection. Candidate variables included age, sex, prior sustained VA (≥30s, hemodynamically unstable, or implantable cardioverter-defibrillator treated ventricular tachycardia; or aborted SCD), syncope, 24-hour premature ventricular complexes count, the number of anterior and inferior leads with T-wave inversion, left and right ventricular ejection fraction. The resulting model was internally validated using bootstrapping. Results: A total of 864 patients with definite ARVC (40±16 years; 53% male) were included. Over 5.75 years (interquartile range, 2.77-10.58) of follow-up, 93 (10.8%) patients experienced LTVA including 15 with SCD/aborted SCD (1.7%). Of the 8 prespecified clinical predictors, only 4 (younger age, male sex, premature ventricular complex count, and number of leads with T-wave inversion) were associated with LTVA. Notably, prior sustained VA did not predict subsequent LTVA (P=0.850). A model including only these 4 predictors had an optimism-corrected C-index of 0.74 (95% CI, 0.69-0.80) and calibration slope of 0.95 (95% CI, 0.94-0.98) indicating minimal over-optimism. Conclusions: LTVA events in patients with ARVC can be predicted by a novel simple prediction model using only 4 clinical predictors. Prior sustained VA and the extent of functional heart disease are not associated with subsequent LTVA events.
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26.
  • Elimam, A, et al. (author)
  • Growth hormone treatment downregulates serum leptin levels in children independent of changes in body mass index
  • 1999
  • In: Hormone research. - : S. Karger AG. - 0301-0163. ; 52:2, s. 66-72
  • Journal article (peer-reviewed)abstract
    • The changes in serum leptin levels during growth hormone (GH) treatment were studied in 27 children, 17 with GH deficiency (GHD), 10 with idiopathic short stature (ISS), and 9 with Prader-Willi syndrome (PWS). Within 1 month of GH treatment, serum leptin levels decreased by 40% in the GHD children (p < 0.01). There was no significant change in serum leptin level in the children with ISS. In children with PWS, the mean serum leptin level decreased by almost 60% after 3 months of treatment (p < 0.001). Thereafter, no further decline was observed in any of the 3 groups. Changes in body composition became evident first after the 3 months of treatment. In the GHD children, the BMI was unchanged while the mean body fat percentage was 2.7% lower after 1 year of GH treatment (p < 0.05). In the ISS children, neither BMI nor body fat percentage were significantly changed during treatment. The PWS children exhibited a significant decrease in BMI after 6 months of GH treatment without any further change during the remaining period of treatment. In this group, the mean body fat percentage decreased from 42 ± 2.4 to 28 ± 2.2% after treatment (p < 0.001). The finding that the fall in leptin occurs before changes in body composition become detectable suggests a direct effect of GH on leptin production, metabolism, or clearance.
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  • Fakhrai-Rad, H, et al. (author)
  • Insulin-degrading enzyme identified as a candidate diabetes susceptibility gene in GK rats.
  • 2000
  • In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 9:14, s. 2149-58
  • Journal article (peer-reviewed)abstract
    • Genetic analysis of the diabetic GK rat has revealed several diabetes susceptibility loci. Congenic strains have been established for the major diabetes locus, Niddm1, by transfer of GK alleles onto the genome of the normoglycemic F344 rat. Niddm1 was dissected into two subloci, physically separated in the congenic strains Niddm1b and Niddm1i, each with at least one disease susceptibility gene. Here we have mapped Niddm1b to 1 cM by genetic and pathophysiological characterization of new congenic substrains for the locus. The gene encoding insulin-degrading enzyme (IDE:) was located to this 1 cM region, and the two amino acid substitutions (H18R and A890V) identified in the GK allele reduced insulin-degrading activity by 31% in transfected cells. However, when the H18R and A890V variants were studied separately, no effects were observed, demonstrating a synergistic effect of the two variants on insulin degradation. No effect on insulin degradation was observed in cell lysates, indicating that the effect is coupled to receptor-mediated internalization of insulin. Congenic rats with the IDE: GK allele displayed post-prandial hyperglycemia, reduced lipogenesis in fat cells, blunted insulin-stimulated glucose transmembrane uptake and reduced insulin degradation in isolated muscle. Analysis of additional rat strains demonstrated that the dysfunctional IDE: allele was unique to GK. These data point to an important role for IDE: in the diabetic phenotype in GK.
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  • Galli, J, et al. (author)
  • Pathophysiological and genetic characterization of the major diabetes locus in GK rats
  • 1999
  • In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 48:12, s. 2463-2470
  • Journal article (peer-reviewed)abstract
    • Genetic studies of the type 2 diabetes-like GK rat have revealed several susceptibility loci for the compound diabetes phenotype. Congenic strains were established for Niddm1, the major quantitative trait locus (QTL) for postprandial glucose levels, by transfer of GK alleles onto the genome of the normoglycemic F344 rat. Despite the polygenic nature of diabetes in GK, the locus-specific diabetes phenotype was retained in the congenic strain Niddmla, containing a GK-derived genomic fragment of 52 cM from the Niddm1 locus. Furthermore, Niddm1 was divided into two non-overlapping loci, physically separated in the two congenic strains Niddmlb and Niddm1i with distinct metabolic phenotypes. Both strains displayed postprandial hyperglycemia and reduced insulin action in isolated adipose cells. Furthermore, Niddm1i already exhibits a pronounced in vivo insulin secretion defect at 65 days, while Niddm1b develops a relative insulin secretory defect at 95 days. This suggests that Niddm1i impairs mechanisms common to insulin secretion in pancreatic B-cells and insulin action in adipocytes. Niddm1b rats show signs of increasing insulin resistance with age associated with obesity, hyperinsulinemia, and dyslipidemia. Moreover, the data indicated nonallelic interaction (epistasis) between Niddm1b and Niddm1i on the postprandial glucose levels. These data emphasize the pathophysiological complexity of diabetes, even within an apparently single QTL, and demonstrate the potential of the GK model in transforming the multifactorial diabetes phenotype into single traits, suitable for positional cloning.
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34.
  • Kamel, A, et al. (author)
  • Effect of growth hormone treatment on insulin action in adipocytes from children with Prader-Willi syndrome
  • 1998
  • In: European journal of endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 138:5, s. 510-516
  • Journal article (peer-reviewed)abstract
    • OBJECTIVE: To study the effect of growth hormone (GH) treatment (2-4 months) on insulin action in adipocytes isolated from children with Prader-Willi syndrome (PWS), in whom GH deficiency appears to be a primary defect. We investigated the complex effects of GH on carbohydrate metabolism, as part of a current clinical trial of GH treatment in children with PWS. METHODS: Biopsies of subcutaneous abdominal adipose tissue were obtained from 12 children with PWS before and after 2-4 months of GH treatment. Lipogenesis was determined by the incorporation of radiolabelled glucose into lipids in isolated adipocytes, and glycerol release to the incubation medium was used as an index of lipolysis. GLUT4 RNA was measured by solution hybridization. RESULTS: With low glucose concentrations, at which glucose transport is rate-limiting, maximal insulin-induced lipogenesis was increased by 120% after GH treatment (P < 0.05), but the sensitivity to insulin (half-maximum effective hormone concentration) was unchanged. This was not accompanied by a significant change in the RNA expression of GLUT4. Neither responsiveness (maximum effect) nor sensitivity of insulin-induced inhibition of lipolysis was affected by GH treatment. CONCLUSIONS: GH treatment of children with PWS results in an upregulation of insulin-induced lipogenesis in isolated adipocytes, with no effect on insulin-induced inhibition of lipolysis. The data suggest that the site of the effect of GH on lipogenesis is distal to the insulin hormone-receptor interaction, but does not involve altered GLUT4 expression.
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37.
  • Kamel, Ihab R., et al. (author)
  • N-Methyl-D-Aspartate (NMDA) Antagonists-S(+)-ketamine, Dextrorphan, and Dextromethorphan-Act as Calcium Antagonists on Bovine Cerebral Arteries
  • 2008
  • In: Journal of Neurosurgical Anesthesiology. - 1537-1921. ; 20:4, s. 241-248
  • Journal article (peer-reviewed)abstract
    • Ketamine an intravenous anesthetic and a major drug of abuse, is a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. Ketamine's enantiomer. S(+)-ketamine, acts stereoselectively on neuronal NMDA receptors. The purpose of this in vitro study was to compare the direct effects of S(+)-ketamine. 2 other noncompetitive NMDA receptor antagonists (dextrorphan and dextromethorphan), and the calcium entry blocker nimodipine on the cerebral vasculature, using bovine middle cerebral arterics as an experimental model. Arterial rings were mounted in isolated tissue chambers equipped with isometric tension transducers to obtain pharmacologic dose-response curves. In the absence of exogenous vasoconstrictor, the NMDA antagonists or nimodipine had negligible effects oil cerebral arterial tone. When rings were preconstricted with either potassium or the stable thromboxane A(2) mimetic U46619. the NMDA antagonists and nimodipine each produced dose-dependent relaxation. Prior endothelial stripping had no effect on subsequent drug-induced relaxation of K+-constricted rings. In Ca2+-deficient media containing either potassium or U46619. the NMDA antagonists and nimodipine each produced competitive inhibition of subsequent Ca2+ induced constriction. In additional experiments, arterial strips were mounted in isolated tissue chambers to directly measure calcium uptake, using (45)calcium (Ca-45) as a radioactive tracer. The NMDA antagonists and nimodipine each blocked potasium-stimulated or U46619-stilmulated Ca-45 uptake into arterial strips. These results indicate that S(+)-ketamine, dextrorphan, arteries by acting as calcium antagonists; they all inhibit Ca-45 uptake through both potential-operated (potassium) and receptor-operated (U46619) channels in cerebrovascular smooth muscle.
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  • Kamel, Mohamed, et al. (author)
  • Synthesis, Optical, Magnetic and Thermodynamic Properties of Rocksalt Li1.3Nb0.3Mn0.4O2 Cathode Material for Li-Ion Batteries
  • 2021
  • In: Crystals. - : MDPI. - 2073-4352. ; 11:7
  • Journal article (peer-reviewed)abstract
    • Since the discovery of the reversible intercalation of lithium-ion materials associated with promising electrochemical properties, lithium-containing materials have attracted attention in the research and development of effective cathode materials for lithium-ion batteries. Despite various studies on synthesis, and electrochemical properties of lithium-based materials, fairly little fundamental optical and thermodynamic studies are available in the literature. Here, we report on the structure, optical, magnetic, and thermodynamic properties of Li-excess disordered rocksalt, Li1.3Nb0.3Mn0.4O2 (LNMO) which was comprehensively studied using powder X-ray diffraction, transient absorption spectroscopy, magnetic susceptibility, and low-temperature heat capacity measurements. Charge carrier dynamics and electron-phonon coupling in LNMO were studied using ultra-fast laser spectroscopy. Magnetic susceptibility and specific heat data are consistent with the onset of long-range antiferromagnetic order at the Neel temperatures of 6.5 (1.5) K. The effective magnetic moment of LNMO is found to be 3.60 mu B. The temperature dependence of the inverse magnetic susceptibility follows the Curie-Weiss law in the high-temperature region and shows negative values of the Weiss temperature 52 K (3), confirming the strong AFM interactions.
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39.
  • Mansouri, Kamel, et al. (author)
  • CERAPP : Collaborative Estrogen Receptor Activity Prediction Project
  • 2016
  • In: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 124:7, s. 1023-1033
  • Journal article (peer-reviewed)abstract
    • BACKGROUND: Humans are exposed to thousands of man-made chemicals in the environment. Some chemicals mimic natural endocrine hormones and, thus, have the potential to be endocrine disruptors. Most of these chemicals have never been tested for their ability to interact with the estrogen receptor (ER). Risk assessors need tools to prioritize chemicals for evaluation in costly in vivo tests, for instance, within the U.S. EPA Endocrine Disruptor Screening Program. OBJECTIVES: We describe a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) and demonstrate the efficacy of using predictive computational models trained on high-throughput screening data to evaluate thousands of chemicals for ER-related activity and prioritize them for further testing. METHODS: CERAPP combined multiple models developed in collaboration with 17 groups in the United States and Europe to predict ER activity of a common set of 32,464 chemical structures. Quantitative structure-activity relationship models and docking approaches were employed, mostly using a common training set of 1,677 chemical structures provided by the U.S. EPA, to build a total of 40 categorical and 8 continuous models for binding, agonist, and antagonist ER activity. All predictions were evaluated on a set of 7,522 chemicals curated from the literature. To overcome the limitations of single models, a consensus was built by weighting models on scores based on their evaluated accuracies. RESULTS: Individual model scores ranged from 0.69 to 0.85, showing high prediction reliabilities. Out of the 32,464 chemicals, the consensus model predicted 4,001 chemicals (12.3%) as high priority actives and 6,742 potential actives (20.8%) to be considered for further testing.CONCLUSION: This project demonstrated the possibility to screen large libraries of chemicals using a consensus of different in silico approaches. This concept will be applied in future projects related to other end points.
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40.
  • Mansouri, Kamel, et al. (author)
  • CoMPARA : Collaborative Modeling Project for Androgen Receptor Activity
  • 2020
  • In: Journal of Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 128:2, s. 1-17
  • Journal article (peer-reviewed)abstract
    • BACKGROUND: Endocrine disrupting chemicals (EDCs) are xenobiotics that mimic the interaction of natural hormones and alter synthesis, transport, or metabolic pathways. The prospect of EDCs causing adverse health effects in humans and wildlife has led to the development of scientific and regulatory approaches for evaluating bioactivity. This need is being addressed using high-throughput screening (HTS) in vitro approaches and computational modeling.OBJECTIVES: In support of the Endocrine Disruptor Screening Program, the U.S. Environmental Protection Agency (EPA) led two worldwide consortiums to virtually screen chemicals for their potential estrogenic and androgenic activities. Here, we describe the Collaborative Modeling Project for Androgen Receptor Activity (CoMPARA) efforts, which follows the steps of the Collaborative Estrogen Receptor Activity Prediction Project (CERAPP).METHODS: The CoMPARA list of screened chemicals built on CERAPP's list of 32,464 chemicals to include additional chemicals of interest, as well as simulated ToxCast (TM) metabolites, totaling 55,450 chemical structures. Computational toxicology scientists from 25 international groups contributed 91 predictive models for binding, agonist, and antagonist activity predictions. Models were underpinned by a common training set of 1,746 chemicals compiled from a combined data set of 11 ToxCast (TM)/Tox21 HTS in vitro assays.RESULTS: The resulting models were evaluated using curated literature data extracted from different sources. To overcome the limitations of single-model approaches, CoMPARA predictions were combined into consensus models that provided averaged predictive accuracy of approximately 80% for the evaluation set.DISCUSSION: The strengths and limitations of the consensus predictions were discussed with example chemicals; then, the models were implemented into the free and open-source OPERA application to enable screening of new chemicals with a defined applicability domain and accuracy assessment. This implementation was used to screen the entire EPA DSSTox database of similar to 875,000 chemicals, and their predicted AR activities have been made available on the EPA CompTox Chemicals dashboard and National Toxicology Program's Integrated Chemical Environment.
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43.
  • Nicolas, Aude, et al. (author)
  • Genome-wide Analyses Identify KIF5A as a Novel ALS Gene
  • 2018
  • In: Neuron. - : Cell Press. - 0896-6273 .- 1097-4199. ; 97:6, s. 1268-1283.e6
  • Journal article (peer-reviewed)abstract
    • To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.
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46.
  • Shahroz, M., et al. (author)
  • COVID-19 digital contact tracing applications and techniques : A review post initial deployments
  • 2021
  • In: Transportation Engineering. - : Elsevier BV. - 2666-691X. ; 5
  • Journal article (peer-reviewed)abstract
    • The coronavirus disease 2019 (COVID-19) is a severe global pandemic that has claimed millions of lives and continues to overwhelm public health systems in many countries. The spread of COVID-19 pandemic has negatively impacted the human mobility patterns such as daily transportation-related behavior of the public. There is a requirement to understand the disease spread patterns and its routes among neighboring individuals for the timely implementation of corrective measures at the required placement. To increase the effectiveness of contact tracing, countries across the globe are leveraging advancements in mobile technology and Internet of Things (IoT) to aid traditional manual contact tracing to track individuals who have come in close contact with identified COVID-19 patients. Even as the first administration of vaccines begins in 2021, the COVID-19 management strategy will continue to be multi-pronged for the foreseeable future with digital contact tracing being a vital component of the response along with the use of preventive measures such as social distancing and the use of face masks. After some months of deployment of digital contact tracing technology, deeper insights into the merits of various approaches and the usability, privacy, and ethical trade-offs involved are emerging. In this paper, we provide a comprehensive analysis of digital contact tracing solutions in terms of their methodologies and technologies in the light of the new data emerging about international experiences of deployments of digital contact tracing technology. We also provide a discussion on open challenges such as scalability, privacy, adaptability and highlight promising directions for future work.
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47.
  • White, Helen E., et al. (author)
  • Establishment of the first World Health Organization International Genetic Reference Panel for quantitation of BCR-ABL mRNA
  • 2010
  • In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 116:22, s. E111-E117
  • Journal article (peer-reviewed)abstract
    • Serial quantitation of BCR-ABL mRNA levels is an important indicator of therapeutic response for patients with chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia, but there is substantial variation in the real-time quantitative polymerase chain reaction methodologies used by different testing laboratories. To help improve the comparability of results between centers we sought to develop accredited reference reagents that are directly linked to the BCR-ABL international scale. After assessment of candidate cell lines, a reference material panel comprising 4 different dilution levels of freeze-dried preparations of K562 cells diluted in HL60 cells was prepared. After performance evaluation, the materials were assigned fixed percent BCR-ABL/control gene values according to the International Scale. A recommendation that the 4 materials be established as the first World Health Organization International Genetic Reference Panel for quantitation of BCR-ABL translocation by real-time quantitative polymerase chain reaction was approved by the Expert Committee on Biological Standardization of the World Health Organization in November 2009. We consider that the development of these reagents is a significant milestone in the standardization of this clinically important test, but because they are a limited resource we suggest that their availability is restricted to manufacturers of secondary reference materials.
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