544 research outputs found

    Comparison of 1-repetition-maximum performance across 3 weightlifting overhead pressing exercises and sport groups

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    Objective: This study aimed to (I) compare the one repetition maximum (1RM) performance between the push press (PP), push jerk (PJ) and split jerk (SJ), and (II) explore these differences between weightlifters, CrossFit® athletes and a mixed group of athletes. Method: Forty-six resistance trained male (age: 28.8 ± 6.4 years; height: 180.0 ± 6.0 cm; body mass: 84.1 ± 10.2 kg; weightlifting training experience: 3.64 ± 3.14 years) participated in this study. The 1RM performance of the PP, PJ and SJ were assessed during the same session in a sequential order (i.e. combined 1RM assessment method). Thirty-six participants were re-tested to determine between-session reliability of the 1RM values. Results: Intraclass correlation coefficients (ICC) and associated 95% confidence intervals showed a high between-session reliability for the PP (ICC = 0.98 [0.95-0.99]), PJ (ICC = 0.99 [0.98-1.00]) and SJ (ICC = 0.99 [0.98-1.00]). There was a significant main effect of exercise (2 = 0.662) and exercise x group interaction (2 = 0.066) on the 1RM performance (p<0.0001), while the main effect of group did not reach statistical significance (p=0.072). Conclusion: This study provides evidence that the weightlifting overhead pressing derivatives impact the 1RM performance. In addition, the interaction of exercise and sport group was caused by the higher differences in the 1RM performance between-exercises for weightlifters compared to CrossFit® and a mixed group of athletes. Therefore, strength and conditioning professionals should be aware that the differences in 1RM performance between weightlifting overhead pressing derivatives may be affected by the sport group

    Does sex impact the differences and relationships in the one repetition maximum performance across weightlifting overhead pressing exercises?

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    This study aimed to determine the impact of sex on the differences and relationships of the one repetition maximum (1RM) performance between 3 overhead pressing exercises (push press [PP], push jerk [PJ] and split jerk [SJ]). 15 men (body mass [BM]: 82.3 ± 9.9 kg; weightlifting training experience: 2.6 ± 1.6 years) and 15 women (BM: 64.4 ± 7.0 kg; weightlifting training experience: 2.2 ± 1.4 years) participated in this study. A ratio-scaled (1RM·BM) was used for the comparison between them. The 1RM of the 3 exercises were evaluated within the same testing session using a combined 1RM assessment method. The interaction effect of exercise and sex did not reach statistical significance (p = 0.671; η = 0.001). In contrast, there were significant main effects of exercise (p ≤ 0.01) and sex (p < 0.001) with medium (η = 0.096) and large effect sizes (η = 0.306), respectively. A similar main effect of exercise was reported for both men (PP [1.0 ± 0.1 kg·kg] < PJ [1.1 ± 0.2 kg·kg] ∼ SJ [1.2 ± 0.2 kg·kg]) and women (PP [0.8 ± 0.1 kg·kg] < PJ [0.9 ± 0.2 kg·kg] ∼ SJ [0.9 ± 0.2 kg·kg]). The 1RM performance of the 3 exercises was significantly correlated for men (r [range] = 0.856-0.963) and women (r [range] = 0.636-0.925). Sex does not affect the differences in the 1RM performance across weightlifting overhead pressing exercises. However, stronger correlations and lower variation in the 1RM performance during the PP, PJ, and SJ are expected for men compared with women

    Soluble tumor necrosis factor receptor 1 and 2 predict outcomes in advanced chronic kidney disease : a prospective cohort study

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    Background : Soluble tumor necrosis factor receptors 1 (sTNFR1) and 2 (sTNFR2) have been associated to progression of renal failure, end stage renal disease and mortality in early stages of chronic kidney disease (CKD), mostly in the context of diabetic nephropathy. The predictive value of these markers in advanced stages of CKD irrespective of the specific causes of kidney disease has not yet been defined. In this study, the relationship between sTNFR1 and sTNFR2 and the risk for adverse cardiovascular events (CVE) and all-cause mortality was investigated in a population with CKD stage 4-5, not yet on dialysis, to minimize the confounding by renal function. Patients and methods : In 131 patients, CKD stage 4-5, sTNFR1, sTNFR2 were analysed for their association to a composite endpoint of all-cause mortality or first non-fatal CVE by univariate and multivariate Cox proportional hazards models. In the multivariate models, age, gender, CRP, eGFR and significant comorbidities were included as covariates. Results : During a median follow-up of 33 months, 40 events (30.5%) occurred of which 29 deaths (22.1%) and 11 (8.4%) first non-fatal CVE. In univariate analysis, the hazard ratios (HR) of sTNFR1 and sTNFR2 for negative outcome were 1.49 (95% confidence interval (CI): 1.28-1.75) and 1.13 (95% CI: 1.06-1.20) respectively. After adjustment for clinical covariables (age, CRP, diabetes and a history of cardiovascular disease) both sTNFRs remained independently associated to outcomes (HR: sTNFR1: 1.51, 95% CI: 1.30-1.77; sTNFR2: 1.13, 95% CI: 1.06-1.20). A subanalysis of the non-diabetic patients in the study population confirmed these findings, especially for sTNFR1. Conclusion : sTNFR1 and sTNFR2 are independently associated to all-cause mortality or an increased risk for cardiovascular events in advanced CKD irrespective of the cause of kidney disease

    aPKC Inhibition by Par3 CR3 Flanking Regions Controls Substrate Access and Underpins Apical-Junctional Polarization

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    Atypical protein kinase C (aPKC) is a key apical-basal polarity determinant and Par complex component. It is recruited by Par3/Baz (Bazooka in Drosophila) into epithelial apical domains through high-affinity interaction. Paradoxically, aPKC also phosphorylates Par3/Baz, provoking its relocalization to adherens junctions (AJs). We show that Par3 conserved region 3 (CR3) forms a tight inhibitory complex with a primed aPKC kinase domain, blocking substrate access. A CR3 motif flanking its PKC consensus site disrupts the aPKC kinase N lobe, separating P-loop/αB/αC contacts. A second CR3 motif provides a high-affinity anchor. Mutation of either motif switches CR3 to an efficient in vitro substrate by exposing its phospho-acceptor site. In vivo, mutation of either CR3 motif alters Par3/Baz localization from apical to AJs. Our results reveal how Par3/Baz CR3 can antagonize aPKC in stable apical Par complexes and suggests that modulation of CR3 inhibitory arms or opposing aPKC pockets would perturb the interaction, promoting Par3/Baz phosphorylation

    Increased ventral striatal volume in college-aged binge drinkers

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    BACKGROUND Binge drinking is a serious public health issue associated with cognitive, physiological, and anatomical differences from healthy individuals. No studies, however, have reported subcortical grey matter differences in this population. To address this, we compared the grey matter volumes of college-age binge drinkers and healthy controls, focusing on the ventral striatum, hippocampus and amygdala. METHOD T1-weighted images of 19 binge drinkers and 19 healthy volunteers were analyzed using voxel-based morphometry. Structural data were also covaried with Alcohol Use Disorders Identification Test (AUDIT) scores. Cluster-extent threshold and small volume corrections were both used to analyze imaging data. RESULTS Binge drinkers had significantly larger ventral striatal grey matter volumes compared to controls. There were no between group differences in hippocampal or amygdalar volume. Ventral striatal, amygdalar, and hippocampal volumes were also negatively related to AUDIT scores across groups. CONCLUSIONS Our findings stand in contrast to the lower ventral striatal volume previously observed in more severe forms of alcohol use disorders, suggesting that college-age binge drinkers may represent a distinct population from those groups. These findings may instead represent early sequelae, compensatory effects of repeated binge and withdrawal, or an endophenotypic risk factor

    Staphylococcus aureus bacteriuria as a prognosticator for outcome of Staphylococcus aureus bacteremia: a case-control study

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    <p>Abstract</p> <p>Background</p> <p>When <it>Staphylococcus aureus </it>is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of <it>S. aureus </it>bacteriuria among patients with <it>S. aureus </it>bacteremia.</p> <p>Methods</p> <p>A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for <it>S. aureus</it>, within 72 hours of positive blood culture for <it>S. aureus</it>. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done.</p> <p>Results</p> <p>Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible <it>S. aureus </it>(MSSA). Among 61 cases and 247 controls, predictors of <it>S. aureus </it>bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06) and genitourinary infection (OR = 9.2, p = 0.002). Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002). In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004), bladder catheter use (2.0, 1.0-4.0, p = 0.06), and Charlson score (1.1, 1.1-1.3, p = 0.02). Neither length of stay nor methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) infection was a predictor of <it>S. aureus </it>bacteriuria or death.</p> <p>Conclusions</p> <p>Among patients with <it>S. aureus </it>bacteremia, those with <it>S. aureus </it>bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.</p

    Acute WNT signalling activation perturbs differentiation within the adult stomach and rapidly leads to tumour formation

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    A role for WNT signalling in gastric carcinogenesis has been suggested due to two major observations. First, patients with germline mutations in adenomatous polyposis coli (APC) are susceptible to stomach polyps and second, in gastric cancer, WNT activation confers a poor prognosis. However, the functional significance of deregulated WNT signalling in gastric homoeostasis and cancer is still unclear. In this study we have addressed this by investigating the immediate effects of WNT signalling activation within the stomach epithelium. We have specifically activated the WNT signalling pathway within the mouse adult gastric epithelium via deletion of either glycogen synthase kinase 3 (GSK3) or APC or via expression of a constitutively active β-catenin protein. WNT pathway deregulation dramatically affects stomach homoeostasis at very short latencies. In the corpus, there is rapid loss of parietal cells with fundic gland polyp (FGP) formation and adenomatous change, which are similar to those observed in familial adenomatous polyposis. In the antrum, adenomas occur from 4 days post-WNT activation. Taken together, these data show a pivotal role for WNT signalling in gastric homoeostasis, FGP formation and adenomagenesis. Loss of the parietal cell population and corresponding FGP formation, an early event in gastric carcinogenesis, as well as antral adenoma formation are immediate effects of nuclear β-catenin translocation and WNT target gene expression. Furthermore, our inducible murine model will permit a better understanding of the molecular changes required to drive tumourigenesis in the stomach

    Adipose atrophy in cancer cachexia:morphologic and molecular analysis of adipose tissue in tumour-bearing mice

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    Extensive loss of adipose tissue is a hallmark of cancer cachexia but the cellular and molecular basis remains unclear. This study has examined morphologic and molecular characteristics of white adipose tissue in mice bearing a cachexia-inducing tumour, MAC16. Adipose tissue from tumour-bearing mice contained shrunken adipocytes that were heterogeneous in size. Increased fibrosis was evident by strong collagen-fibril staining in the tissue matrix. Ultrastructure of 'slimmed' adipocytes revealed severe delipidation and modifications in cell membrane conformation. There were major reductions in mRNA levels of adipogenic transcription factors including CCAAT/enhancer binding protein alpha (C/EBPα), CCAAT/enhancer binding protein beta, peroxisome proliferator-activated receptor gamma, and sterol regulatory element binding protein-1c (SREBP-1c) in adipose tissue, which was accompanied by reduced protein content of C/EBPα and SREBP-1. mRNA levels of SREBP-1c targets, fatty acid synthase, acetyl CoA carboxylase, stearoyl CoA desaturase 1 and glycerol-3-phosphate acyl transferase, also fell as did glucose transporter-4 and leptin. In contrast, mRNA levels of peroxisome proliferators-activated receptor gamma coactivator-1alpha and uncoupling protein-2 were increased in white fat of tumour-bearing mice. These results suggest that the tumour-induced impairment in the formation and lipid storing capacity of adipose tissue occurs in mice with cancer cachexia. © 2006 Cancer Research UK
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