The muscle – fat duel or why obese children are taller?

BACKGROUND: Obesity the epidemic of our times appears to be a problem that is easy to resolve: just eat less and move more. However, this very common condition has turned out to be extremely troublesome, and in some cases even irreversible. METHODS: The interplay between less muscle and more fat tissue is discussed from physiological perspectives with an emphasis on the early years of childhood. RESULTS: It is suggested that the coordinated muscle-fat interactions lead to a fluctuating exchange economy rate. This bodily economic decision, slides between thrift (more fat) and prodigal (more muscle) strategies. The thrift strategy results not only in obesity and less physical activity but also in other maladies which the body is unable to manage. What leads to obesity (less muscle, more fat) might be very difficult to reverse at adulthood, prevention at childhood is thus recommended. CONCLUSION: Early recognition of the ailment (low muscle mass) is crucial. Based on studies demonstrating a 'rivalry' between muscle build-up and height growth at childhood, it is postulated that among the both taller and more obese children the percentage of children with lower muscle mass will be higher. A special, body/muscle-building gymnastics program for children is suggested as a potential early intervention to prevent the ill progress of obesity

EFFECT OF INORGANIC NITRATE ON MAX VOLUNTARY CONTRACTION AND ISOKINETIC TORQUE ACROSS THE MENSTRUAL CYCLE

Austin C. Hogwood1, Joaquin Ortiz de Zevallos Muñoz1, Ka\u27eo Kruse1, Jeison DeGuzman1, Meredith Buckley1, Arthur Weltman, FACSM1,2, Jason Allen, FACSM1,2. 1University of Virginia, Charlottesville, VA. 2University of Virginia School of Medicine, Charlottesville, VA. Background: Inorganic nitrate (NO3-) supplementation increases nitric oxide (NO) bioavailability and may improve exercise performance. In females, estrogen increases endogenous eNOS production of NO, but estrogen fluctuates throughout the menstrual cycle (MC). It is unknown if different phases of the MC or exogenous NO3-supplementation impact maximal voluntary isometric contraction (MVIC), isokinetic torque, or power in apparently healthy young females. The purpose of this study was to examine potential differences in MVIC, isokinetic torque, and power between the early (EF) and late follicular (LF) phase of the MC, and with either beetroot juice (BR-containing ~13 mmol NO3-) or identical placebo (PL) supplementation. Methods: Seven recreationally active females (age: 24.7 ± 4 yrs, VO2peak: 34.4 ± 8 mL/kg/min) with normal MC and not using contraceptives were recruited in this double-blinded crossover study. Subjects were randomized to consume BR or PL, twice daily, for 5 days prior to testing that was conducted during EF and again during LF (1-5 and 11-14 days after menses onset, respectively). Subjects also consumed the supplement 2 hours prior to the testing, and a 14-day washout period was utilized between treatments. A linear mixed effects model was used to examine differences between MC phase, supplements, and interaction effects. MVIC (at 90°), peak torque (PT), PT normalized to bodyweight, time to PT, average PT, and average power were acquired via a Biodex isokinetic dynamometer during knee extension when measured at 180°, 270°, and 360°/second. Data are mean ± SD and significance was determined a priori at p \u3c 0.05.Results: Mixed effects models revealed no significant differences in MVIC, power, or any measures of torque either between the MC, or the PL and BR supplementations (all p \u3e 0.05). There were also no significant interaction effects for MVIC (PL EF: 1.12 ± 0.3; PL LF: 1.10 ± 0.3; BR EF: 1.18 ± 0.3; BR LF: 1.14 ± 0.3 Hz; p = 0.93) or any other outcomes. Conclusion: This preliminary data suggests that neither the follicular phase of the menstrual cycle, nor NO3- supplementation, impacts MVIC or outcomes such as peak torque or average power during isokinetic knee extension in healthy young females

THE EFFECT OF DIETARY NITRATE SUPPLEMENTATION ON SKELETAL MUSCLE CONTRACTILE PROPERTIES IN FEMALES AND MALES

Joaquin Ortiz de Zevallos1, Austin C. Hogwood1, Ka’eo K. Kruse1, Jeison de Guzman1, Meredith Buckley1, Alexandra F. DeJong1,2, Arthur L. Weltman, FACSM1, Jason D. Allen, FACSM1. 1University of Virginia, Charlottesville, VA. 2The Micheli Center for Sports Injury Prevention, Boston, MA. Nitric Oxide (NO) plays a pivotal role in muscle contractile function. Inorganic nitrate (NO3-) supplementation has been demonstrated to increase NO bioavailability and potentially improve exercise performance. Currently the effects of dietary nitrate (NO3-) on muscle function in young healthy females compared to males is understudied and unclear. Purpose: To determine sex-differences of dietary NO3- supplementation on skeletal muscle function during knee extension and muscular endurance during a time to failure (TF) task. Methods: Seven healthy females (age 24.0±3.6y, BMI 24.0±3.9) and ten healthy males (age 23.4±3.7y, BMI 25.1±2.6) were randomized in a double-blind, placebo-controlled crossover study. Female subjects were tested during the Early Follicular phase of the menstrual cycle to control for estrogen levels. Subjects ingested 70ml twice/day for 5 days, either NO3--rich Beet root juice (BRJ ~13mmol NO3-) or NO3--depleted placebo (PL). The last dose (140ml) was ingested 2h prior to laboratory arrival. Knee extension contractile function was assessed using a Biodex 4 isokinetic dynamometer at three different speeds (180°, 270°, and 360°/sec) during 10 consecutive maximal efforts. Subjects were given a thirty second rest between each speed. After a 5min rest, subjects completed a TF task which consisted of cycles of 3 sec contraction at 60% maximal isometric voluntary contraction and 2 sec rest for as long as possible. An inability to maintain the 60% threshold on three different occasions despite verbal encouragement throughout the test was considered as the end of the test. Results: Repeated Measures Two-Way ANOVA revealed that there were no significant differences in peak torque (nM/Kg), average power (watts/kg) and peak power (Watts/Kg) at all speeds for males or females between BR and PL conditions (p \u3e 0.05 for all). Similarly, TF was not statistically different in females (PL; 269.14±161.17 vs BRJ; 277.14±157.50 sec; p \u3e 0.05) or males (PL; 228.20±171.13 vs BRJ;194.13±99.65 sec; p \u3e 0.05). Conclusion: Dietary nitrate supplementation did not increase muscle contractile function or endurance in healthy young males or females

Treatment for hepatitis C virus infection among people who inject drugs attending opioid substitution treatment and community health clinics: The ETHOS Study

Aims: To estimate adherence and response to therapy for chronic hepatitis C virus (HCV) infection among people with a history of injecting drug use. A secondary aim was to identify predictors of HCV treatment response. Design: Prospective cohort recruited between 2009 and 2012. Participants were treated with peg-interferon alfa-2a/ribavirin for 24 (genotypes 2/3, G2/3) or 48weeks (genotype 1, G1). Setting: Six opioid substitution treatment (OST) clinics, two community health centres and one Aboriginal community-controlled health organization providing drug treatment services in New South Wales, Australia. Participants: Among 415 people with a history of injecting drug use and chronic HCV assessed by a nurse, 101 were assessed for treatment outcomes (21% female). Measurements: Study outcomes were treatment adherence and sustained virological response (SVR, undetectable HCV RNA >24weeks post-treatment). Findings: Among 101 treated, 37% (n=37) had recently injected drugs (past 6months) and 62% (n=63) were receiving OST. Adherence ≥80% was 86% (n=87). SVR was 74% (75 of 101), with no difference observed by sex (males: 76%, females: 67%, P=0.662). In adjusted analysis, age <35 (versus ≥45years) [adjusted odds ratio (aOR)=5.06, 95% confidence interval (CI)=1.47, 17.40] and on-treatment adherence ≥80% independently predicted SVR (aOR=19.41, 95% CI=3.61, 104.26]. Recent injecting drug use at baseline was not associated with SVR. Conclusions: People with a history of injecting drug use and chronic hepatitis C virus attending opioid substitution treatment and community health clinics can achieve adherence and responses to interferon-based therapy similar to other populations, despite injecting drugs at baseline. Younger age and adherence are predictive of improved response to hepatitis C virus therapy

Ocorrência de tuberculose doença entre contatos de tuberculose sensível e multirresistente Occurrence of active tuberculosis in households inhabited by patients with susceptible and multidrug-resistant tuberculosis

INTRODUÇÃO: Desde os primeiros anos da quimioterapia anti-tuberculose, existe polêmica a respeito da transmissibilidade, infectividade, virulência e patogenicidade de bacilos sensíveis e resistentes à quimioterapia. OBJETIVO: Determinar a ocorrência de casos de tuberculose doença entre contatos intra-domiciliares de tuberculose multirresistente e tuberculose sensível. MÉTODO: Foi realizado um estudo caso-controle, sendo considerado tuberculose multirresistente o caso de portador de bacilo resistente a pelo menos rifampicina e isoniazida, e tuberculose sensível o caso que tivesse feito o primeiro tratamento num período semelhante ao primeiro tratamento do caso de tuberculose multirresistente, estando o paciente curado no momento da entrevista. Contato foi definido como o residente no domicílio do caso índice. Os casos foram selecionados a partir dos resultados dos testes de sensibilidade obtidos pelo método das proporções no Laboratório Central do Estado do Ceará, e os controles constituídos por pacientes bacilíferos registrados no Programa de Controle da Tuberculose, entre 1.990 e 1.999. RESULTADOS: Foram avaliados 126 portadores de tuberculose multirresistente e 176 de tuberculose sensível. O número de contatos foi de 557 no grupo dos casos, 752 no grupo controle e a média de contatos por caso índice foi de 4,42 e 4,27 respectivamente. Entre os casos, 4,49% dos contatos (25/557) fizeram tratamento para tuberculose após os casos índices. Esse percentual foi de 5,45% (41/752) entre os controles (p = 0,4468). Ocorreu micro-epidemia de tuberculose multirresistente confirmada por teste de sensibilidade em oito famílias. CONCLUSÃO: Os resultados deste estudo sugerem que a ocorrência de tratamentos de tuberculose gerados entre contatos intra-domiciliares de tuberculose sensível e tuberculose multirresistente é semelhante.<br>BACKGROUND: Since the first years of antituberculosis chemotherapy, there has been controversy regarding the transmissibility, infectiousness, virulence and pathogenicity of susceptible and drug-resistant strains of Mycobacterium tuberculosis. OBJECTIVE: To determine the incidence of active tuberculosis (TB) among individuals cohabiting with patients infected with susceptible and multidrug-resistant tuberculosis (MDR-TB). METHODS: A case-control study was conducted. Cases of MDR-TB were defined as those infected with M. tuberculosis strains resistant to at least rifampin and isoniazid. Susceptible TB cases (controls) were defined as those first treated at approximately the same time as the first treatment of the MDR-TB cases - and cured by the time of the interview. Study cases were selected on the basis of the results of susceptibility tests, using the proportion method, carried out at the Central Laboratory of Public Health of the State of Ceará. The control group consisted of patients enrolled in the Tuberculosis Control Program between 1990 and 1999. RESULTS: We evaluated 126 patients and 176 controls. The number of individuals sharing the household with patients was 557 in the MDR-TB group and 752 in the controls. The average number of exposed individuals per index case was 4.42 and 4.27 among patients and controls, respectively. Of the 557 MDR-TB-exposed individuals, 4.49% (25) received antituberculosis treatment after the respective index case had begun treatment, compared to 5.45% (41/752) among the controls (p = 0.4468). Microepidemics of MDR-TB were confirmed in eight families. CONCLUSION: Our results suggest that the incidence of active TB is comparable between households inhabited by MDR-TB patients and those inhabited by susceptible-TB patients

Thyroid Hormone and Estrogen Regulate Exercise-Induced Growth Hormone Release

Growth hormone (GH) regulates whole body metabolism, and physical exercise is the most potent stimulus to induce its secretion in humans. The mechanisms underlying GH secretion after exercise remain to be defined. The aim of this study was to elucidate the role of estrogen and pituitary type 1 deiodinase (D1) activation on exercise-induced GH secretion. Ten days after bilateral ovariectomy, animals were submitted to 20 min of treadmill exercise at 75% of maximum aerobic capacity and tissues were harvested immediately or 30 min after exercise. Non-exercised animals were used as controls. A significant increase in D1 activity occurred immediately after exercise (~60%) in sham-operated animals and GH was higher (~6-fold) 30 min after exercise. Estrogen deficient rats exhibited basal levels of GH and D1 activity comparable to those found in control rats. However, after exercise both D1 activity and serum GH levels were blunted compared to sedentary rats. To understand the potential cause-effect of D1 activation in exercise-induced GH release, we pharmacologically blocked D1 activity by propylthiouracil (PTU) injection into intact rats and submitted them to the acute exercise session. D1 inhibition blocked exercise-induced GH secretion, although basal levels were unaltered. In conclusion, estrogen deficiency impairs the induction of thyroid hormone activating enzyme D1 in the pituitary, and GH release by acute exercise. Also, acute D1 activation is essential for exercise-induced GH response