Guiding of Charged Particle Beams in Curved Plasma-Discharge Capillaries.

We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. We experimentally prove that the guiding is much less affected by the beam chromatic dispersion with respect to a conventional bending magnet and, with the support of numerical simulations, we show that it can even be made dispersionless by employing larger discharge currents. This proof-of-principle experiment extends the use of plasma-based devices, that revolutionized the field of particle accelerators enabling the generation of GeV beams in few centimeters. Compared to state-of-the-art technology based on conventional bending magnets and quadrupole lenses, these results provide a compact and affordable solution for the development of next-generation tabletop facilities.

Acceleration and focusing of relativistic electron beams in a compact plasma device.

Plasma wakefield acceleration represented a breakthrough in the field of particle accelerators by pushing beams to gigaelectronvolt energies within centimeter distances. The large electric fields excited by a driver pulse in the plasma can efficiently accelerate a trailing witness bunch paving the way toward the realization of laboratory-scale applications like free-electron lasers. However, while the accelerator size is tremendously reduced, upstream and downstream of it the beams are still handled with conventional magnetic optics with sizable footprints and rather long focal lengths. Here we show the operation of a compact device that integrates two active-plasma lenses with short focal lengths to assist the plasma accelerator stage. We demonstrate the focusing and energy gain of a witness bunch whose phase space is completely characterized in terms of energy and emittance. These results represent an important step toward the accelerator miniaturization and the development of next-generation table-top machines.

Severe Bartter syndrome type 1: Prompt postnatal management thanks to antenatal identification of SLC12A1 pathogenic variants.

Bartter syndrome (BS) refers to a group of hereditary kidney disorders. One antenatal form is Bartter syndrome type 1 (BS1), caused by pathogenic variants in the SLC12A1 gene. We report a case of BS1 presenting with severe polyhydramnios. The fetus was found to carry three pathogenic variants of SLC12A1, leading to the antenatal diagnosis of BS1 and its prompt management. At age 18 days, clinical conditions were complicated by the onset of sepsis requiring supportive measures as well as steroid and antibiotic therapy. Any newborn with an antenatal history of polyhydramnios or postnatal polyuria should be suspected of having BS, since delayed diagnosis may lead to rapid renal failure.

Methodological Issues and the Impact of Age Stratification on the Proportion of Participants with Low Appendicular Lean Mass When Adjusting for Height and Fat Mass Using Linear Regression: Results from the Canadian Longitudinal Study on Aging.

BACKGROUND: Using residual values calculated from models regressing appendicular lean mass on fat mass and height is one of several suggested strategies for adjusting appendicular lean mass for body size when measuring sarcopenia. However, special consideration is required when using this technique in different subgroups in order to capture the correct individuals as sarcopenic. OBJECTIVES: To provide guidance about how to conduct stratified analyses for the regression adjustment technique using age groups as an example. DESIGN: Cross-sectional study. SETTING: Data collected at baseline (2012-2015) for the Canadian Longitudinal Study on Aging. PARTICIPANTS: Community dwelling participants of European descent aged 45 to 85 years (n=25,399). MEASUREMENTS: Appendicular lean mass, height, and weight were measured. Sex-specific residuals were calculated in participants before and after stratifying participants by age group (45-54, 55-64, 65-74, 75-85 years). Cut offs corresponding to the sex-specific 20th percentile residual values in participants ≥65 years were determined first in the residuals calculated in all participants and residuals calculated in only those aged ≥65 years. For each set of cut offs, the percentage of age and sex-stratified participants with low appendicular lean mass were compared for the residuals calculated in all participants and the residuals calculated after stratifying by age. RESULTS: In 12,622 males and 12,737 females, regardless of the cut off used, the percentage of participants with low appendicular lean mass decreased with age when residuals were calculated after age stratification. When the residuals were calculated in all participants, the percentage of participants with sarcopenia increased from the youngest to the oldest age groups. CONCLUSIONS: Sex-specific residuals in all participants should be calculated prior to stratifying the sample by age group, or other stratification variables, for the purposes of developing appendicular lean mass cut offs or subgroup analyses.

Stereotactic Body Radiotherapy Versus Metastasectomy in Patients With Pulmonary Metastases From Soft Tissue Sarcoma.

The lung is the preferred site of metastasis from soft tissue sarcoma (STS). This systematic review aims to evaluate the outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy (MTS) for the treatment of lung metastases from STS. A systematic review was carried out according to the PRISMA protocol. PubMed, Medline, EMBASE, Cochrane Library, Ovid and Web of Knowledge databases were searched for English-language articles to December 2018 using a predefined strategy. Retrieved studies were independently screened and rated for relevance. Data were extracted by two researchers. In total, there were 1306 patients with STS: 1104 underwent MTS and 202 had SBRT. The mean age ranged from 40 to 55.8 years in the MTS group and from 47.9 to 64 years in the SBRT group. The cumulative death rate was 72% (95% confidence interval 59-85%) in the MTS group and 56% (38-74%) in the SBRT group. The cumulative mean overall survival time was 46.7 months (36.4-57.0%) in the MTS group and 47.6 months (33.7-61.5%) in the SBRT group. The cumulative rate of patients alive with disease was 5% (2-9%) in the MTS group and 15% (6-36%) in the SBRT group. Finally, the cumulative rate of patients alive without disease in the two groups was 19% (9-29%) and 20% (10-50%), respectively. Our study showed that local treatment of pulmonary metastases from STS with SBRT, compared with surgery, was associated with a lower cumulative overall death rate and similar overall survival time and survival rates without disease. By contrast, SBRT was associated with a higher survival rate with disease than MTS. Large randomised trials are necessary to confirm these findings and to establish whether SBRT may be a reliable option for early stage disease.

The prevalence of sarcopenia in community-dwelling older adults, an exploration of differences between studies and within definitions: a systematic review and meta-analyses.

Background: sarcopenia in ageing is a progressive decrease in muscle mass, strength and/or physical function. This review aims to summarise the definitions of sarcopenia in community-dwelling older adults and explore similarities and differences in prevalence estimates by definition. Methods: a systematic review was conducted to identify articles which estimated sarcopenia prevalence in older populations using search terms for sarcopenia and muscle mass. Overall prevalence for each sarcopenia definition was estimated stratified by sex and ethnicity. Secondary analyses explored differences between studies and within definitions, including participant age, muscle mass measurement techniques and thresholds for muscle mass and gait speed. Results: in 109 included articles, eight definitions of sarcopenia were identified. The lowest pooled prevalence estimates came from the European Working Group on Sarcopenia/Asian Working Group on Sarcopenia (12.9%, 95% confidence interval: 9.9-15.9%), International Working Group on Sarcopenia (9.9%, 3.2-16.6%) and Foundation for the National Institutes of Health (18.6%, 11.8-25.5%) definitions. The highest prevalence estimates were for the appendicular lean mass (ALM)/weight (40.4%, 19.5-61.2%), ALM/height (30.4%, 20.4-40.3%), ALM regressed on height and weight (30.4%, 20.4-40.3%) and ALM / body mass index (24.2%, 18.3-30.1%) definitions. Within definitions, the age of study participants and the muscle mass cut points used were substantive sources of between-study differences. Conclusion: estimates of sarcopenia prevalence vary from 9.9 to 40.4%, depending on the definition used. Significant differences in prevalence exist within definitions across populations. This lack of agreement between definitions needs to be better understood before sarcopenia can be appropriately used in a clinical context.

The effect of exercise mode on the acute response of satellite cells in old men.

AIM: A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults. METHODS: Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m(-2) ) were randomly assigned to complete an acute bout of either resistance exercise, high-intensity interval exercise on a cycle ergometer or moderate-intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections. RESULTS: Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II-associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high-intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I-associated SC co-expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001). CONCLUSION: Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high-intensity interval exercise was also more potent than moderate-intensity aerobic exercise in inducing satellite cell activity.

Gene expression profiling in human skeletal muscle during recovery from eccentric exercise.

We used cDNA microarrays to screen for differentially expressed genes during recovery from exercise-induced muscle damage in humans. Male subjects (n = 4) performed 300 maximal eccentric contractions, and skeletal muscle biopsy samples were analyzed at 3 h and 48 h after exercise. In total, 113 genes increased 3 h postexercise, and 34 decreased. At 48 h postexercise, 59 genes increased and 29 decreased. On the basis of these data, we chose 19 gene changes and conducted secondary analyses using real-time RT-PCR from muscle biopsy samples taken from 11 additional subjects who performed an identical bout of exercise. Real-time RT-PCR analyses confirmed that exercise-induced muscle damage led to a rapid (3 h) increase in sterol response element binding protein 2 (SREBP-2), followed by a delayed (48 h) increase in the SREBP-2 gene targets Acyl CoA:cholesterol acyltransferase (ACAT)-2 and insulin-induced gene 1 (insig-1). The expression of the IL-1 receptor, a known regulator of SREBP-2, was also elevated after exercise. Taken together, these expression changes suggest a transcriptional program for increasing cholesterol and lipid synthesis and/or modification. Additionally, damaging exercise induced the expression of protein kinase H11, capping protein Z alpha (capZalpha), and modulatory calcineurin-interacting protein 1 (MCIP1), as well as cardiac ankryin repeat protein 1 (CARP1), DNAJB2, c-myc, and junD, each of which are likely involved in skeletal muscle growth, remodeling, and stress management. In summary, using DNA microarrays and RT-PCR, we have identified novel genes that respond to skeletal muscle damage, which, given the known biological functions, are likely involved in recovery from and/or adaptation to damaging exercise.

Analysis of global mRNA expression in human skeletal muscle during recovery from endurance exercise.

To search for novel transcriptional pathways that are activated in skeletal muscle after endurance exercise, we used cDNA microarrays to measure global mRNA expression after an exhaustive bout of high-intensity cycling (approximately 75 min). Healthy, young, sedentary males performed the cycling bout, and skeletal muscle biopsies were taken from the vastus lateralis before, and at 3 and 48 h after exercise. We examined mRNA expression in individual muscle samples from four subjects using cDNA microarrays, used repeated-measures significance analysis of microarray (SAM) to determine statistically significant expression changes, and confirmed selected results using real-time RT-PCR. In total, the expression of 118 genes significantly increased 3 h postcycling and 8 decreased. At 48 h, the expression of 29 genes significantly increased and 5 decreased. Many of these are potentially important novel genes involved in exercise recovery and adaptation, including several involved in 1) metabolism and mitochondrial biogenesis (FOXO1, PPARdelta, PPARgamma, nuclear receptor binding protein 2, IL-6 receptor, ribosomal protein L2, aminolevulinate delta-synthase 2); 2) the oxidant stress response (metalothioneins 1B, 1F, 1G, 1H, 1L, 2A, 3, interferon regulatory factor 1); and 3) electrolyte transport across membranes [Na+-K+-ATPase (beta3), SERCA3, chloride channel 4]. Others include genes involved in cell stress, proteolysis, apoptosis, growth, differentiation, and transcriptional activation, as well as all three nuclear receptor subfamily 4A family members (Nur77, Nurr1, and Nor1). This study is the first to characterize global mRNA expression during recovery from endurance exercise, and the results provide potential insight into 1) the transcriptional contributions to homeostatic recovery in human skeletal muscle after endurance exercise, and 2) the transcriptional contributions from a single bout of endurance exercise to the adaptive processes that occur after a period of endurance exercise training.

Na+,K+-ATPase concentration and fiber type distribution after spinal cord injury.

Complete spinal cord injury (SCI) is characterized, in part, by reduced fatigue-resistance of the paralyzed skeletal muscle during stimulated contractions, but the underlying mechanisms are not fully understood. The effects of complete SCI on skeletal muscle Na(+),K(+)-adenosine triphosphatase (ATPase) concentration, and fiber type distribution were therefore investigated. Six individuals (aged 32.0 +/- 5.3 years) with complete paraplegia (T4-T10; 1-19 years since injury) participated. There was a significantly lower Na(+),K(+)-ATPase concentration in the paralyzed vastus lateralis (VL) when compared to either the subjects' own unaffected deltoid or literature values (from our laboratory, utilizing the same methodology) of VL Na(+),K(+)-ATPase concentration for the healthy able-bodied (141.6 +/- 50.0, 213.4 +/- 23.9, 339 +/- 16 pmol/g wet wt., respectively; P < 0.05). There was also a significant negative correlation between the Na(+),K(+)-ATPase concentration in the paralyzed VL and years since injury (r = -0.75, P < 0.05). These findings are clinically relevant as they suggest that reductions in Na(+),K(+)-ATPase contribute to the fatigability of paralyzed muscle after SCI. Unexpectedly, the VL muscles of our subjects had a higher proportion of their area represented by type I fibers compared to literature values for the VL of the healthy able-bodied (52.6 +/- 25.3% vs. 36 +/- 11.3%, respectively; P < 0.05). As all our subjects had upper motor neuron injuries and, therefore, experienced muscle spasticity, our findings warrant further investigation into the relationship between muscle spasticity and fiber type expression after SCI.

Resistance-training-induced adaptations in skeletal muscle protein turnover in the fed state.

Resistance training changes the balance of muscle protein turnover, leading to gains in muscle mass. A longitudinal design was employed to assess the effect that resistance training had on muscle protein turnover in the fed state. A secondary goal was investigation of the potential interactive effects of creatine (Cr) monohydrate supplementation on resistance-training-induced adaptations. Young (N = 19, 23.7 +/- 3.2 year), untrained (UT), healthy male subjects completed an 8-week resistance-training program (6 d/week). Supplementation with Cr had no impact on any of the variables studied; hence, all subsequent data were pooled. In the UT and trained (T) state, subjects performed an acute bout of resistance exercise with a single leg (exercised, EX), while their contralateral leg acted as a nonexercised (NE) control. Following exercise, subjects were fed while receiving a primed constant infusion of [d5]- and [15N]-phenylalanine to determine the fractional synthetic and breakdown rates (FSR and FBR), respectively, of skeletal muscle proteins. Acute exercise increased FSR (UT-NE, 0.065 +/- 0.025 %/h; UT-EX, 0.088 +/- 0.032 %/h; P < 0.01) and FBR (UT-NE, 0.047 +/- 0.023 %/h; UT-EX, 0.058 +/- 0.026 %/h; P < 0.05). Net balance (BAL = FSR - FBR) was positive in both legs (P < 0.05) but was significantly greater (+65%) in the EX versus the NE leg (P < 0.05). Muscle protein FSR and FBR were greater at rest following T (FSR for T-NE vs. UT-NE, +46%, P < 0.01; FBR for T-NE vs. UT-NE, +81%, P < 0.05). Resistance training attenuated the acute exercise-induced rise in FSR (T-NE vs. T-EX, +20%, P = 0.65). The present results demonstrate that resistance training resulted in an elevated resting muscle protein turnover but an attenuation of the acute response of muscle protein turnover to a single bout of resistance exercise.

Creatine-dextrose and protein-dextrose induce similar strength gains during training.

BACKGROUND: Creatine supplementation during resistance exercise training has been reported to induce greater increases in fat-free mass (FFM), muscle fiber area, and strength when compared with a placebo. We have recently shown that timing of nutrient delivery in the postexercise period can have positive effects on whole body protein turnover (B. D. Roy et al., Med Sci Sports Exerc. 32(8):1412-1418, 2000). PURPOSE: We tested the hypothesis that a postexercise protein-carbohydrate supplement would result in similar increases in FFM, muscle fiber area, and strength as compared with creatine monohydrate (CM), during a supervised 2-month resistance exercise training program in untrained men. METHODS: Young healthy male subjects were randomized to receive either CM and glucose (N = 11; CM 10 g + glucose 75 g [CR-CHO] (CELL-Tech)) or protein and glucose (N = 8; casein 10 g + glucose 75 g [PRO+CHO]), using double-blinded allocation. Participants performed 8 wk of whole body split-routine straight set weight training, 1 h.d(-1), 6 d.wk(-1). Measurements, pre- and post-training were made of fat-free mass (FFM; DEXA), total body mass, muscle fiber area, isokinetic knee extension strength (45 and 240 degrees.s(-1)), and 1 repetition maximal (1RM) strength for 16 weight training exercises. RESULTS: Total body mass increased more for CR-CHO (+4.3 kg, 5.4%) as compared with PRO-CHO (+1.9 kg, 2.4%) (P < 0.05 for interaction) and FFM increased after training (P < 0.01) but was not significantly different between the groups (CR-CHO = +4.0 kg, 6.4%; PRO-CHO = +2.6 kg, 4.1%) (P = 0.11 for interaction). Muscle fiber area increased similarly after training for both groups (approximately 20%; P < 0.05). Training resulted in an increase in 1RM for each of the 16 activities (range = 14.2-39.9%) (P < 0.001), isokinetic knee extension torque (P < 0.01), with no treatment effects upon any of the variables. CONCLUSIONS: We concluded that postexercise supplementation with PRO-CHO resulted in similar increases in strength after a resistance exercise training program as compared with CR-CHO. However, the greater gains in total mass for the CR-CHO group may have implications for sport-specific performance.

Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis.

Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men (n = 13) and women (n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3-4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of L-[1-(13)C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (-19.6%) and plasma leucine rate of appearance (-7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.

Selective serotonin reuptake inhibitors: Their effect on high-intensity exercise performance.

OBJECTIVE: To determine the neuromuscular and performance effects of acute and long-term exposure to selective serotonin reuptake inhibitors (SSRIs). DESIGN: Two randomized, double-blind, crossover studies. SETTING: Departments of Kinesiology and Medicine, McMaster University, Hamilton, Ont, Canada. PARTICIPANTS: Eleven healthy, college-aged men in the acute study; 12 healthy, college-aged men in the chronic study. INTERVENTIONS: In the acute study, subjects were given a placebo and fluoxetine (40 mg) 6 hours before testing, in the chronic study, they were given fluoxetine (40mg/d) and an identical placebo for 2 weeks before testing. MAIN OUTCOME MEASURES: Target measures were maximum voluntary contractions (MVCs), evoked peak torque, and percentage of motor unit activation for muscle strength and central drive. Repeated Wingate cycle ergometer tests were used to measure anaerobic power, capacity, and fatigue index. VO2max tests (80%, 90%) were used to measure time to exhaustion and cardiorespiratory responses. RESULTS: In the acute study phase, MVC was lower for fluoxetine versus placebo (p =.05) and a slight fatigue resistance was measured in the repeated Wingate tests for the fluoxetine group; however, there were no affects on any other measured variable. In the chronic study phase, minute ventilation was lower for the fluoxetine trial (p <.05); however, there were no treatment affects on any of the other measurements. CONCLUSION: Acute and chronic SSRI intake does not effect strength or high-intensity exercise performance in young adult men.

Myoadenylate deaminase deficiency does not affect muscle anaplerosis during exhaustive exercise in humans.

1. Myoadenylate deaminase (AMPD) deficiency is present in 1--2 % of the population. In theory, this deficiency may alter exercise energy metabolism by impairing the purine nucleotide cycle (PNC) and reducing tricarboxylic acid (TCA) cycle anaplerosis. The role of the PNC in TCA cycle anaplerosis is still a debated issue in physiology. Using patients with the AMPD1 mutation will allow a human 'knockout' approach to answering this question. 2. Muscle AMPD activity and genotype (whole blood AMPD1 analysis) was used to classify participants into three groups: n = 3 with absence of AMPD activity and -/- AMPD1 genotype (homozygous); n = 4 with less than 50 % normal AMPD activity and +/- genotype (heterozygous) and n = 12 with normal AMPD activity and +/+ genotype (control). Biopsies were taken from the vastus lateralis muscle before and after incremental cycle ergometry exercise to exhaustion. The muscle biopsies were analysed for AMPD activity, purine nucleotides/nucleosides and bases, creatine, phosphocreatine, amino acids, and the TCA cycle intermediates malate, citrate and fumarate. 3. Time to exhaustion on the cycle ergometer was not different between groups. Muscle adenosine monophosphate increased significantly with exercise for homozygous subjects as compared with the other groups (P < 0.05). Inosine monophosphate increased significantly after exercise for control (P < 0.05) but not for the homozygous subjects. There were no other between-group differences for any other measured variables. 4. In summary, complete and partial muscle AMPD deficiency did not affect TCA cycle anaplerosis, phosphocreatine hydrolysis, energy charge or exercise performance.

The utility of resistance exercise training and amino acid supplementation for reversing age-associated decrements in muscle protein mass and function.

Advancing age is associated with reduced skeletal muscle protein synthesis, altered expression of and chemical modifications to muscle proteins, reduced muscle strength, muscle strength per unit muscle mass and muscle power (sarcopenia). These age-associated impairments in the quantity and quality of contractile protein contribute to physical disability and frailty, a loss of independent function, the risk of falling and fractures, and escalating health-care costs. Progressive resistance exercise training is a potent, non-pharmacologic, efficacious therapy for the impairment in muscle quantity and quality in middle age and physically frail adults. Evidence is accumulating that dietary amino acid supplementation may also improve muscle protein balance in the elderly. Several potential cellular mechanisms for the loss of muscle protein and resistance exercise-induced improvements in muscle quantity and quality in elderly adults are reviewed.

Recurrent spontaneous abortion. Etiologic factors.

BACKGROUND: Spontaneous abortion is the most common complication of pregnancy. It may be unique, remaining random and having no consequences on the reproductive process, or it can repeat itself, starting a clinical picture known as recurrent spontaneous abortion or habitual abortion. The term of RSA syndrome is used to define the repetition of three or more consecutive abortions before the 24th week. METHODS: A population of 195 couples with recurrent spontaneous abortion were screened for genetic, metabolic, infective, morphological, endocrine and autoimmune factors. Eighty-five completed the investigation, 44 are being tested and 66 did not complete the diagnostic course. Causes of recurrent abortion were evaluated in relation to the period of abortion and number of embryo losses. RESULTS: Forty-six percent of patients who completed the investigation turned out to be sine causa, which is in accordance with the findings in literature. CONCLUSIONS: Couple with RSA require accurate counselling and it is fundamental to eliminate any pathologies that can be discovered so as to improve the likelihood of the pregnancy's reaching term.

Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistance-training-induced changes in body composition and skeletal muscle in older men.

BACKGROUND: Very limited data suggest that meat consumption by older people may promote skeletal muscle hypertrophy in response to resistance training (RT). OBJECTIVE: The objective of this study was to assess whether the consumption of an omnivorous (meat-containing) diet would influence RT-induced changes in whole-body composition and skeletal muscle size in older men compared with a lactoovovegetarian (LOV) (meat-free) diet. DESIGN: Nineteen men aged 51-69 y participated in the study. During a 12-wk period of RT, 9 men consumed their habitual omnivorous diets, which provided approximately 50% of total dietary protein from meat sources (beef, poultry, pork, and fish) (mixed-diet group). Another 10 men were counseled to self-select an LOV diet (LOV-diet group). RESULTS: Maximal strength of the upper- and lower-body muscle groups that were exercised during RT increased by 10-38% (P < 0.001), independent of diet. The RT-induced changes in whole-body composition and skeletal muscle size differed significantly between the mixed- and LOV-diet groups (time-by-group interactions, P < 0. 05). With RT, whole-body density, fat-free mass, and whole-body muscle mass increased in the mixed diet group but decreased in the LOV- diet group. Type II muscle fiber area of the vastus lateralis muscle increased with RT for all men combined (P < 0.01), and the increase tended to be greater in the mixed-diet group (16.2 +/- 4.4 %) than in the LOV diet group (7.3 +/- 5.1%). Type I fiber area was unchanged with RT in both diet groups. CONCLUSION: Consumption of a meat-containing diet contributed to greater gains in fat-free mass and skeletal muscle mass with RT in older men than did an LOV diet.

Direct measurement of high-energy phosphate compounds in patients with neuromuscular disease.

Several neuromuscular disorders are associated with reductions in intramuscular adenosine triphosphate (ATP) and/or phosphocreatine (PCr). These alterations have been primarily characterized using (31)P-magnetic resonance spectroscopy ((31)P-MRS). We prospectively measured total creatine, PCr, and ATP in muscle biopsies from 81 patients: normal controls (n = 33), mitochondrial cytopathy (n = 8), neuropathic (n = 3), dystrophy/congenital myopathies (n = 7), inflammatory myopathy (n = 12), and miscellaneous myopathies (n = 18) using direct biochemical analysis. Intramuscular concentrations of PCr and ATP were lower for the dystrophy/congenital myopathy, inflammatory myopathy, and mitochondrial disease patients with ragged red fiber (RRF) as compared with normal controls (P < 0.05). Total creatine was lower for the dystrophy/congenital myopathy group as compared with the normal control group (P < 0.05). These values compare favorably to results from other studies using (31)P-MRS and provide external validation for the values obtained using that method. Given the reductions in high-energy phosphate compounds in these patients, there is the potential for therapeutic intervention with creatine monohydrate supplementation.