Circulating myostatin is reduced with aging in humans but not altered by short-term, high intensity training

Introduction: Ageing involves a loss of muscle mass and function. The rate of decline is associated with negative health outcomes and increased mortality (1). Muscle atrophy is observed at a predictable rate from 30 years of age (2), however maintenance of function is seen in masters athletes > 60 years of age (3). Myostatin acts as a negative regulator of muscle mass (4) and underlies hypertrophy with chronic resistance training (5) and atrophy in chronic conditions (4). Experiment 1: Declared healthy participants (n = 83, 18 - 75 years of age, 36 male, 47 female) were recruited. Body composition, metabolic rate, grip strength and 6-minute walk test were recorded. Venous blood was collected and total myostatin concentration (herein referred to as myostatin) quantified by enzyme-linked immunosorbent assay. Total myostatin was lower in females compared with males (2176.1 [135.3] vs. 2788.7 [180.2] pg.mL-1 [p = 0.007]). Stepwise regression observed that myostatin concentration is best predicted firstly by gender, then by age (r = 0.399, p = 0.02), and was not further improved by the addition of measures of metabolism, muscle mass or function. Experimental 2: A cohort of aged sedentary (SED) males (n = 14; 63.9 [5.6] years of age) and masters athletes (lifelong exerciser [LEX]; n = 10, 61.1 [5.8] years of age) completed 6 weeks of high intensity interview training (HITT). Two way ANOVA suggested no group (SED, LEX) × time (pre, post) interaction on myostatin concentration (p = 0.649), nor a main effect of time (p = 0.757), however there was a trend towards increased myostatin in the LEX group relative to SED (p = 0.083). Discussion: Loss of muscle mass and function occurs at a predictable rate from ~30 years of age, however the rate of loss differs between active and inactive populations. Here we demonstrate that total circulating myostatin decreases as age increases, and differs significantly between males and females. Total circulating myostatin negatively correlates with increasing age, however alterations in myostatin do not appear after short term training interventions. Longer term activity may alter myostatin, thus our next work will follow up experiment 2 with a 3 year longitudinal analysis

Circulating myostatin is reduced with aging in humans but not altered by short-term, high intensity training

Ageing involves a loss of muscle mass and function. The rate of decline is associated with negative health outcomes and increased mortality (1). Muscle atrophy is observed at a predictable rate from 30 years of age (2), however maintenance of function is seen in masters athletes > 60 years of age (3). Myostatin acts as a negative regulator of muscle mass (4) and underlies hypertrophy with chronic resistance training (5) and atrophy in chronic conditions (4). Experiment 1: Declared healthy participants (n = 83, 18 - 75 years of age, 36 male, 47 female) were recruited. Body composition, metabolic rate, grip strength and 6-minute walk test were recorded. Venous blood was collected and total myostatin concentration (herein referred to as myostatin) quantified by enzyme-linked immunosorbent assay. Total myostatin was lower in females compared with males (2176.1 [135.3] vs. 2788.7 [180.2] pg.mL-1 [p = 0.007]). Stepwise regression observed that myostatin concentration is best predicted firstly by gender, then by age (r = 0.399, p = 0.02), and was not further improved by the addition of measures of metabolism, muscle mass or function. Experimental 2: A cohort of aged sedentary (SED) males (n = 14; 63.9 [5.6] years of age) and masters athletes (lifelong exerciser [LEX]; n = 10, 61.1 [5.8] years of age) completed 6 weeks of high intensity interview training (HITT). Two way ANOVA suggested no group (SED, LEX) × time (pre, post) interaction on myostatin concentration (p = 0.649), nor a main effect of time (p = 0.757), however there was a trend towards increased myostatin in the LEX group relative to SED (p = 0.083). Discussion: Loss of muscle mass and function occurs at a predictable rate from ~30 years of age, however the rate of loss differs between active and inactive populations. Here we demonstrate that total circulating myostatin decreases as age increases, and differs significantly between males and females. Total circulating myostatin negatively correlates with increasing age, however alterations in myostatin do not appear after short term training interventions. Longer term activity may alter myostatin, thus our next work will follow up experiment 2 with a 3 year longitudinal analysis

Athenian University Students on Facebook and Privacy: A Fair “Trade-Off ”?

This article explores how Athenian university students “manage” their privacy on Facebook while socially interacting with other users. Survey data of undergraduate students in Athens reveal that the social network site use “validates” and enhances the pre-existing social context and that the relationship level has an impact on the way users contact other users on it. We find that Facebook users feel that they are able to use most of the privacy settings to protect their personal data. Yet, they are concerned about the disclosure of their personal information which is perceived to be their primary responsibility. Despite these concerns, they appear to feel in control of their privacy through the abilities they are offered by the social networking site (SNS). We also argue that even if they realize that they are disclosing their personal information, this doesn’t cause a great deal of insecurity. © 2016, © The Author(s) 2016

An animal model of limitation of gut colonization by carbapenemase-producing Klebsiella pneumoniae using rifaximin

Current knowledge suggests that infection by carbapenem-resistant enterobacteria is preceded by gut colonization. It is hypothesized that colonization is eradicated by non-absorbable antibiotics like rifaximin. We investigated the effect of rifaximin against carbapenem-resistant Klebsiella pneumoniae (CRKP) in vitro and in a mouse model. We studied the in vitro efficacy of rifaximin against 257 CRKP clinical isolates, 188 KPC producers and 69 OXA-48 producers, by minimum inhibitory concentration and time-kill assays. We then developed a model of gut colonization by feeding 30 C57Bl6 mice with 108 cfu of one KPC-KP isolate for 7 days; mice were pre-treated orally with saline, omeprazole or ampicillin. Then, another 60 mice with established KPC-2 gut colonization received orally for 7 consecutive days rifaximin 180 mg/kg dissolved in ethanol and 4% bile or vehicle. On days 0, 3 and 7 stool samples were collected; mice were sacrificed for determination of tissue outgrowth. At a concentration of 1000 μg/ml rifaximin inhibited 84.8% of CRKP isolates. Α 3 × log10 decrease of the starting inoculum was achieved by 100, 250 and 500 μg/ml of rifaximin after 24 h against 25, 55 and 55% of isolates. Pre-treatment with ampicillin was necessary for gut colonization by KPC-KP. Treatment with rifaximin succeeded in reducing KPC-KP load in stool and in the intestine. Rifaximin inhibits at clinically meaningful gut concentrations the majority of CRKP isolates and is efficient against gut colonization by KPC-KP. © 2022, The Author(s)

Alleviation of organic solvent inhibition with improved copper recovery from low grade sulphide ore by bioaugmentation with newly isolated Candida sp. OR3 and OR6

All rights reserved.Organic compounds used in solvent extraction (SX) processes severely inhibit copper bioleaching microorganisms. In this experimental study, it was found that bioleaching microorganisms at 0.5% and 0.75% organic (SX) resulted in lower Cu recovery from low grade sulphide ore. Two new Candida species OR3 and OR6 were isolated from the liquid phase in solvent extraction process and these isolated strains were tolerant and capable of growing on 1% organic phase. The inhibition of organic phase to bioleaching microorganisms was alleviated by the addition of the 2 isolates and as a result the Cu recovery remained at high level. This is the first study which shows that the organic SX mixture inhibition to acidophilic microorganism can be overcome by the addition of other microorganisms

Analysing the relationship between the problem-solving-related beliefs, competence and teaching of three Cypriot primary teachers

In this article, we analyse the problem-solving-related beliefs, competence and classroom practice of three Cypriot upper-primary teachers. Data derived from semistructured interviews focused on teachers’ beliefs about the nature of mathematical problems, problem-solving, and their competence as both problem-solvers and teachers of problem-solving; clinical interviews during which teachers solved a context-free geometrical problem, and observations of a lesson during which teachers introduced that problem to students of grade six. Analyses, structured by a framework derived from key problem-solving literature, indicated firstly, that the framework was an effective tool, sensitive to variation within and across the data from teachers, and secondly, that all participants, in largely explicable ways, exhibited consistency and inconsistency in the ways in which their beliefs, competence and practice interacted. Some implications for further research are discussed

Immigrant pupils in elementary classrooms of Cyprus: how teachers view them as learners of mathematics

Research in diverse mathematics classrooms suggests that pupils’ learning is influenced by both linguistic and cultural factors. In recent years, the demographics of Cypriot (mathematics) classrooms have become very diverse. In 2003, the Ministry of Education and Culture introduced the Zones of Educational Priorities, a UNESCO strategy for positive discrimination, to support schools with high proportions of immigrant pupils. This paper examines how elementary teachers in such schools see their immigrant pupils as learners of mathematics. The findings confirm two main factors identified in the literature (language and culture), yet the Cypriot teachers in this study share some particular views on how these features impact mathematics learning. Some recommendations for policy-making and future research are discussed at the end of this paper