Project description:Previous studies have shown that low cardiorespiratory fitness (CRF), visceral obesity and low muscle mass may share pathophysiological mechanisms, such as insulin resistance and chronic inflammation. In this study, we investigated whether low CRF is associated with low muscle mass, visceral obesity, and visceral obesity combined with low muscle mass.The associations between CRF and low muscle mass and combined low muscle mass and visceral obesity were examined in 298 apparently healthy adults aged 20-70 years. Low muscle mass was defined using a skeletal muscle mass index (SMI) that was calculated using dual energy X-ray absorptiometry. Visceral obesity was defined as a visceral fat area (VFA) exceeding 100 cm2 in women and 130 cm2 in men. We classified the participants into 4 low muscle mass/visceral obesity groups according to SMI and VFA. CRF was measured using a cycle ergometer test.CRF level correlated positively with SMI and negatively with VFA. Individuals with low muscle mass had lower CRF values than those without low muscle mass. After adjustment for age, sex, lifestyle factors, and markers for insulin resistance and inflammation, participants in the lowest quartile of CRF had an odds ratio (OR) for low muscle mass of 4.98 compared with those in the highest quartile (95% confidence interval (CI) = 1.19-12.99; P for trend = 0.001) and an OR for combined low muscle mass and visceral obesity of 31.46 (95% CI = 4.31-229.68; P for trend = 0.001).Individuals with lower CRF exhibited increased risk of low muscle mass and combined low muscle mass and visceral obesity. These results suggest that low CRF may be a potential indicator for low muscle mass and combined low muscle mass and visceral obesity in Korean adults.
Project description:Researchers may be interested in finding proteomics runs, which have been deposited into online repositories, that are similar to their own data. However, it is difficult to measure the similarity of a pair of proteomics runs. Here, we present a new method, MS1Connect, that only uses intact peptide scans to calculate the similarity between a pair of runs. We show evidence that the MS1Connect score accurately measures the similarity between two proteomics runs. Specifically, we show that MS1Connect outperforms baseline methods for predicting the species a sample originated. In addition, we show that MS1Connect scores are highly correlated with similarities based o peptide fragment scans by observing a high correlation between MS1Connect scores and the Jaccard index between the sets of confidently detected peptides for a pair of runs.
Project description:Health outcomes of the elderly vary between rural and urban areas. Sarcopenia is diagnosed as loss of muscle strength or impaired physical performance, namely "low muscle function" and low muscle mass. Outcomes of low muscle mass and low muscle function are not equal. This study aimed to investigate the prevalence of low muscle mass, low muscle function, and sarcopenia in rural and urban populations and to determine whether regional differences were associated with each of these components. Participants aged ≥ 69 years (n = 2354) were recruited from three urban districts and one rural district in Korea. Low muscle mass was defined by appendicular lean mass using bioelectrical impedance analysis. Low muscle function was defined by handgrip strength and 5-chair stand test. Sarcopenia was defined as low muscle mass plus low muscle function. The prevalence of low muscle function (53.7% vs. 72.8%), and sarcopenia (16.3% vs. 24.4%) were higher in the rural elderly population. Rural residence was associated with low muscle function (OR 1.63; 95% CI 1.13-2.37, P = 0.009), but not with low muscle mass (OR 0.58; 95% CI 0.22-1.54, P = 0.271) or with sarcopenia (OR 1.13; 95% CI 0.63-2.00, P = 0.683). Interventions to detect and improve low muscle function in rural elderly population are needed.
Project description:IntroductionComputed tomography (CT) can accurately measure muscle mass, which is necessary for diagnosing sarcopenia, even in dialysis patients. However, CT-based screening for such patients is challenging, especially considering the availability of equipment within dialysis facilities. We therefore aimed to develop a bedside prediction model for low muscle mass, defined by the psoas muscle mass index (PMI) from CT measurement.MethodsHemodialysis patients (n = 619) who had undergone abdominal CT screening were divided into the development (n = 441) and validation (n = 178) groups. PMI was manually measured using abdominal CT images to diagnose low muscle mass by two independent investigators. The development group's data were used to create a logistic regression model using 42 items extracted from clinical information as predictive variables; variables were selected using the stepwise method. External validity was examined using the validation group's data, and the area under the curve (AUC), sensitivity, and specificity were calculated.ResultsOf all subjects, 226 (37%) were diagnosed with low muscle mass using PMI. A predictive model for low muscle mass was calculated using ten variables: each grip strength, sex, height, dry weight, primary cause of end-stage renal disease, diastolic blood pressure at start of session, pre-dialysis potassium and albumin level, and dialysis water removal in a session. The development group's adjusted AUC, sensitivity, and specificity were 0.81, 60%, and 87%, respectively. The validation group's adjusted AUC, sensitivity, and specificity were 0.73, 64%, and 82%, respectively.Discussion/conclusionOur results facilitate skeletal muscle screening in hemodialysis patients, assisting in sarcopenia prophylaxis and intervention decisions.
Project description:Sarcopenia is a multifaceted geriatric syndrome associated with the loss of muscle mass. We examined the relationship between low muscle mass and inflammatory cytokines in the context of aging. This study involved 299 participants (127 men and 172 women; mean age 63.3 ± 9.8 years) who underwent health checkups for body composition and inflammatory cytokine (TNF-alpha, IL-6, and MCP-1) levels. Muscle mass was determined using the skeletal muscle mass index. We divided the participants into the normal (N) and low muscle mass (L) groups and compared the levels of inflammatory cytokines in nonelderly (<65 years) and elderly (≥65 years) participants. Among the nonelderly subjects, C-reactive protein was significantly lower in the L group than in the N group (p < 0.05). However, there was no significant difference in the inflammatory cytokine levels between the groups. Among the elderly subjects, the TNF-alpha level was significantly lower in the L group than in the N group (p < 0.05), whereas there were no significant differences in the IL-6 and MCP-1 levels. Moreover, TNF-alpha was identified as a risk factor for the L group in the logistic regression analysis (Exp (B) 0.935, 95% CI: 0.876-0.997, p = 0.04). Although a low TNF-alpha level is a risk factor for low muscle mass, inflammatory cytokine levels are not necessarily elevated in elderly individuals with the loss of muscle mass.
Project description:In order to determine whether dis-regulation of a genetic pathway could explain the increased apoptosis of parp-2-/- double positive thymocytes, the gene expression profiles in double positive thymocytes derived from wild-type and parp-2-/- mice were analysed using Affymetrix oligonucleotide chips (mouse genome 430 2.0).
Project description:ImportanceGiven the risks of postoperative morbidity and its consequent economic burden and impairment to patients undergoing colon resection, evaluating risk factors associated with complications will allow risk stratification and the targeting of supportive interventions. Evaluation of muscle characteristics is an emerging area for improving preoperative risk stratification.ObjectiveTo examine the associations of muscle characteristics with postoperative complications, length of hospital stay (LOS), readmission, and mortality in patients with colon cancer.Design, setting, and participantsThis population-based retrospective cohort study was conducted among 1630 patients who received a diagnosis of stage I to III colon cancer from January 2006 to December 2011 at Kaiser Permanente Northern California, an integrated health care system. Preliminary data analysis started in 2017. Because major complication data were collected between 2018 and 2019, the final analysis using the current cohort was conducted between 2019 and 2020.ExposuresLow skeletal muscle index (SMI) and/or low skeletal muscle radiodensity (SMD) levels were assessed using preoperative computerized tomography images.Main outcomes and measuresLength of stay, any complication (≥1 predefined complications) or major complications (Clavien-Dindo classification score ≥3), 30-day mortality and readmission up to 30 days postdischarge, and overall mortality.ResultsThe mean (SD) age at diagnosis was 64.0 (11.3) years and 906 (55.6%) were women. Patients with low SMI or low SMD were more likely to remain hospitalized 7 days or longer after surgery (odds ratio [OR], 1.33; 95% CI, 1.05-1.68; OR, 1.39; 95% CI, 1.05-1.84, respectively) and had higher risks of overall mortality (hazard ratio, 1.40; 95% CI, 1.13-1.74; hazard ratio, 1.44; 95% CI, 1.12-1.85, respectively). Additionally, patients with low SMI were more likely to have 1 or more postsurgical complications (OR, 1.31; 95% CI, 1.04-1.65) and had higher risk of 30-day mortality (OR, 4.85; 95% CI, 1.23-19.15). Low SMD was associated with higher odds of having major complications (OR, 2.41; 95% CI, 1.44-4.04).Conclusions and relevanceLow SMI and low SMD were associated with longer LOS, higher risk of postsurgical complications, and short-term and long-term mortality. Research should evaluate whether targeting potentially modifiable factors preoperatively, such as preserving muscle mass, could reverse the observed negative associations with postoperative outcomes.
Project description:The muscle index of the first vertebra (L1MI) derived from computed tomography (CT) is an indicator of total skeletal muscle mass. Nevertheless, the cutoff value and utility of L1MI derived from low-dose chest CT (LDCT) remain unclear. Adults who received LDCT for health check-ups in 2017 were enrolled. The cutoff values of L1MI were established in subjects aged 20-60 years. The cutoff values were used in chronic obstructive pulmonary disease (COPD) patients to determine muscle quantity. A total of 1780 healthy subjects were enrolled. Subjects (n = 1393) aged 20-60 years were defined as the reference group. The sex-specific cutoff values of L1MI were 26.2 cm2/m2 for males and 20.9 cm2/m2 for females. Six subjects in the COPD group (6/44, 13.6%) had low L1MI. COPD subjects with low L1MI had lower forced expiratory volume in one second (0.81 ± 0.17 vs. 1.30 ± 0.55 L/s, p = 0.046) and higher COPD assessment test scores (19.5 ± 2.6 vs. 15.0 ± 4.9, p = 0.015) than those with normal L1MI. In conclusion, LDCT in health assessments may provide additional information on sarcopenia.
Project description:BackgroundA universal definition of sarcopenia is still lacking. Since the European criteria have been recently revised, we aimed at studying prevalence of low muscle strength (LMS) and low muscle mass (LMM), as defined according to the European Working Group of Sarcopenia in Older People (EWGSOP) 2 and 1 definitions, and their individual contribution toward mortality and incident mobility disability in a cohort of community-dwelling older people.MethodsLongitudinal analysis of 535 participants of the InCHIANTI study. LMS and LMM were defined according to the criteria indicated in the EWGSOP2 and 1. Cox and log-binomial regressions were used to examine association with mortality and 3-year mobility disability (inability to walk 400 m).ResultsWe observed a lower prevalence of the combination LMM/LMS according to EWGSOP2 compared to EWGSOP1 (3.2% vs 6.2%). Using the new criteria, all sarcopenia components were associated with mortality, although the hazard ratio [HR] for the group LMM/LMS was no longer significant after adjustment for confounders (LMM: HR 2.69, 95% confidence interval [CI] 1.04-6.94; LMS: HR 3.18, 95% CI 1.44-7.01; LMM/LMS: HR 2.95, 95% CI 0.86-10.16). Using EWGSOP1, LMS alone was independently associated with mortality (HR 4.43, 95% CI 1.85-10.57). None of the sarcopenia components conferred a higher risk of mobility disability.ConclusionsThe EWGSOP2 algorithm leads to a reduction in the estimated prevalence of sarcopenia defined as combination of LMM/LMS. The finding that, independent of the adopted criteria, people with LMS and normal mass have a higher mortality risk compared to robust individuals, confirms that evaluation of muscle strength has a central role for prognosis evaluation.