BioMed Central - Most accessed articles

Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism

Tyler Churchward - Venne — 2012-05-17T00:00:00Z

Provision of dietary amino acids increases skeletal muscle protein synthesis (MPS), an effectthat is enhanced by prior resistance exercise. As a fundamentally necessary process in theenhancement of muscle mass, strategies to enhance rates of MPS would be beneficial in thedevelopment of interventions aimed at increasing skeletal muscle mass particularly whencombined with chronic resistance exercise. The purpose of this review article is to provide anupdate on current findings regarding the nutritional regulation of MPS and highlight nutritionbased strategies that may serve to maximize skeletal muscle protein anabolism withresistance exercise. Such factors include timing of protein intake, dietary protein type, therole of leucine as a key anabolic amino acid, and the impact of other macronutrients (i.e.carbohydrate) on the regulation of MPS after resistance exercise. We contend that nutritionalstrategies that serve to maximally stimulate MPS may be useful in the development ofnutrition and exercise based interventions aimed at enhancing skeletal muscle mass whichmay be of interest to elderly populations and to athletes.

How Not To Be A Bioinformatician

Manuel Corpas — 2012-05-28T00:00:00Z

Although published material exists about the skills required for a successful bioinformatics career, strangely enough no work to date has addressed the matter of how to excel at not being a bioinformatician. A set of basic guidelines and a code of conduct is hereby presented to re-address that imbalance for fellow-practitioners whose aim is to not to succeed in their chosen bioinformatics field. By scrupulously following these guidelines one can be sure to regress at a highly satisfactory rate.

The effect of earplugs during the night on the onset of delirium and sleep perception: a randomized controlled trial in intensive care patients

Bart Van Rompaey — 2012-05-04T00:00:00Z

IntroductionThis study hypothesised that a reduction of sound during the night using earplugs could be beneficial in the prevention of intensive care delirium. Two research questions were formulated. First, does the use of earplugs during the night reduce the onset of delirium or confusion in the ICU? Second, does the use of earplugs during the night improve the quality of sleep in the ICU? Methods: A randomized clinical trial included adult intensive care patients in an intervention group of 69 patients sleeping with earplugs during the night and a control group of 67 patients sleeping without earplugs during the night. The researchers were blinded during data collection. Assignment was performed by an independent nurse researcher using a computer program. Eligible patients had an expected length of stay in the ICU of more than 24 hours, were Dutch- or English-speaking and scored a minimum Glasgow Coma Scale of 10. Delirium was assessed using the validated NEECHAM scale, sleep perception was reported by the patient in response to five questions. Results: The use of earplugs during the night lowered the incidence of confusion in the studied intensive care patients. A vast improvement was shown by a Hazard Ratio of 0.47 (95% confidence interval (CI) 0.27 to 0.82). Also, patients sleeping with earplugs developed confusion later than the patients sleeping without earplugs. After the first night in the ICU, patients sleeping with earplugs reported a better sleep perception. Conclusions: Earplugs may be a useful instrument in the prevention of confusion or delirium. The beneficial effects seem to be strongest within 48 hours after admission. The relation between sleep, sound and delirium, however, needs further research.Trial registrationCurrent Controlled Trials ISRCTN36198138

A metagenomic study of diet-dependent interaction between gut microbiota and host in infants reveals differences in immune response

Scott Schwartz — 2012-04-30T00:00:00Z

Background: Gut microbiota and the host exist in a mutualistic relationship, with the functional composition of the microbiota strongly affecting the health and well-being of the host. Thus, it is important to develop a synthetic approach to study the host transcriptome and the microbiome simultaneously. Early microbial colonization in infants is critically important for directing neonatal intestinal and immune development, and is especially attractive for studying the development of human-commensal interactions. Here we report the results from a simultaneous study of the gut microbiome and host epithelial transcriptome of three-month-old exclusively breast- and formula-fed infants. Results: Variation in both host mRNA expression and the microbiome phylogenetic and functional profiles was observed between breast- and formula-fed infants. To examine the interdependent relationship between host epithelial cell gene expression and bacterial metagenomic-based profiles, the host transcriptome and functionally profiled microbiome data were subjected to novel multivariate statistical analyses. Gut microbiota metagenome virulence characteristics concurrently varied with immunity-related gene expression in epithelial cells between the formula-fed and the breast-fed infants. Conclusions: Our data provide insight into the integrated responses of the host transcriptome and microbiome to dietary substrates in the early neonatal period. We demonstrate that differences in diet can affect, via gut colonization, host expression of genes associated with the innate immune system. Furthermore, the methodology presented in this study can be adapted to assess other host-commensal and host-pathogen interactions using genomic and transcriptomic data, providing a synthetic genomics-based picture of host-commensal relationships.

Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice

Hiroshi Shimoda — 2006-03-17T00:00:00Z

Background: An epidemiological study conducted in Italy indicated that coffee has the greatest antioxidant capacity among the commonly consumed beverages. Green coffee bean is rich in chlorogenic acid and its related compounds. The effect of green coffee bean extract (GCBE) on fat accumulation and body weight in mice was assessed with the objective of investigating the effect of GCBE on mild obesity. Methods: Male ddy mice were fed a standard diet containing GCBE and its principal constituents, namely, caffeine and chlorogenic acid, for 14 days. Further, hepatic triglyceride (TG) level was also investigated after consecutive administration (13 days) of GCBE and its constituents. To examine the effect of GCBE and its constituents on fat absorption, serum TG changes were evaluated in olive oil-loaded mice. In addition, to investigate the effect on hepatic TG metabolism, carnitine palmitoyltransferase (CPT) activity in mice was evaluated after consecutive ingestion (6 days) of GCBE and its constituents (caffeine, chlorogenic acid, neochlorogenic acid and feruloylquinic acid mixture). Results: It was found that 0.5% and 1% GCBE reduced visceral fat content and body weight. Caffeine and chlorogenic acid showed a tendency to reduce visceral fat and body weight. Oral administration of GCBE (100 and 200 mg/kg· day) for 13 days showed a tendency to reduce hepatic TG in mice. In the same model, chlorogenic acid (60 mg/kg· day) reduced hepatic TG level. In mice loaded with olive oil (5 mL/kg), GCBE (200 and 400 mg/kg) and caffeine (20 and 40 mg/kg) reduced serum TG level. GCBE (1%), neochlorogenic acid (0.028% and 0.055%) and feruloylquinic acid mixture (0.081%) significantly enhanced hepatic CPT activity in mice. However, neither caffeine nor chlorogenic acid alone was found to enhance CPT activity. Conclusion: These results suggest that GCBE is possibly effective against weight gain and fat accumulation by inhibition of fat absorption and activation of fat metabolism in the liver. Caffeine was found to be a suppressor of fat absorption, while chlorogenic acid was found to be partially involved in the suppressive effect of GCBE that resulted in the reduction of hepatic TG level. Phenolic compounds such as neochlorogenic acid and feruloylquinic acid mixture, except chlorogenic acid, can enhance hepatic CPT activity.

Longitudinal investigation of natural killer cells and cytokines in chronic fatigue syndrome/myalgic encephalomyelitis

Ekua Brenu — 2012-05-09T00:00:00Z

Background: Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is an etiologically unexplained disorder characterised by irregularities in various aspects of the immunological function. Presently, it is unknown whether these immunological changes remain consistent over time. This study investigates Natural Killer (NK) cell cytotoxic activity, NK cell subsets (CD56brightCD16- and CD56dimCD16+) and cytokines, over the course of a12 month period in patients with CFS/ME. Methods: The participants in the study comprised 65 (47.2+/-11.5 years) CFS/ME participants and 21 (45.2 +/-9.3 years) non-fatigued controls. Flow cytometry protocols were used to assess NK subsets and NK cytotoxic activity at various time points that included baseline (T1), 6 (T2) and 12 months (T3). Cytokine secretions were measured following mitogenic stimulation of peripheral blood mononuclear cells. Results: NK cytotoxic activity was significantly decreased in the CFS/ME patients at T1, T2 and T3 compared to the non-fatigued group. Additionally, in comparison to the non-fatigued controls, the CFS/ME group had significantly lower numbers of CD56brightCD16- NK cells at both T1 and T2. Interestingly, following mitogenic stimulation, cytokine secretion revealed significant increases in IL-10, IFN-gamma and TNF-alpha at T1 in the CFS/ME group. A significant decrease was observed at T2 in the CFS/ME group for IL-10 and IL-17A while at T3, IL-2 was increased in the CFS/ME group in comparison to the non- fatigued controls. Overall cytotoxic activity was significantly decreased at T3 compared to T1 and T2. CD56brightCD16- NK cells were much lower at T2 compared to the T1 and T3. IL-10 and IL-17A secretion was elevated at T2 in comparison to the T1 and T3. Conclusion: These results confirm decreases in immune function in CFS/ME patients, suggesting an increased susceptibility to viral and other infections. Furthermore NK cytotoxic activity may be a suitable biomarker for diagnosing CFS/ME as it was consistently decreased during the course of the 12 months study.

Q&A: 'Toxic' effects of sugar: should we be afraid of fructose?

Luc Tappy — 2012-05-21T00:00:00Z

No abstract. First Paragraph:Carbohydrate is an essential component of our diet. What about fructose? Can we live without any fructose intake?Glucose is unequivocally a central component of human energy metabolism. It constitutes the nearly exclusive energy fuel for the brain, since neurons lack the enzymes required for fatty acid oxidation. The only exception to this exclusive glucose metabolism in the brain is starvation, when the expression of monocarboxylate transporters increases in brain cells, which then become able to use the ketone bodies (beta-hydroxybutyric acid and aceto-acetic acid) produced by the liver. As a consequence of this exclusive reliance on glucose for brain metabolism, intricate hormonal and neural mechanisms have evolved to maintain a constant level of glucose in the blood.

Food Advertising and Marketing Directed at Children and Adolescents in the US

Mary Story — 2004-02-10T00:00:00Z

In recent years, the food and beverage industry in the US has viewed children and adolescents as a major market force. As a result, children and adolescents are now the target of intense and specialized food marketing and advertising efforts. Food marketers are interested in youth as consumers because of their spending power, their purchasing influence, and as future adult consumers. Multiple techniques and channels are used to reach youth, beginning when they are toddlers, to foster brand-building and influence food product purchase behavior. These food marketing channels include television advertising, in-school marketing, product placements, kids clubs, the Internet, toys and products with brand logos, and youth-targeted promotions, such as cross-selling and tie-ins. Foods marketed to children are predominantly high in sugar and fat, and as such are inconsistent with national dietary recommendations. The purpose of this article is to examine the food advertising and marketing channels used to target children and adolescents in the US, the impact of food advertising on eating behavior, and current regulation and policies.

Ingesting a pre-workout supplement containing caffeine, B-vitamins, amino acids, creatine, and beta-alanine before exercise delays fatigue while improving reaction time and muscular endurance

Brandon Spradley — 2012-03-30T00:00:00Z

Background: The purpose of this study was to determine the effects of the pre-workout supplement Assault™ (MusclePharm, Denver, CO, USA) on upper and lower body muscular endurance, aerobic and anaerobic capacity, and choice reaction time in recreationally-trained males. Subjective feelings of energy, fatigue, alertness, and focus were measured to examine associations between psychological factors and human performance. Methods: Twelve recreationally-trained males participated in a 3-week investigation (mean +/- SD, age: 28 +/- 5 y, height: 178 +/- 9 cm, weight: 79.2 +/- 15.7 kg, VO2max: 45.7 +/- 7.6 ml/kg/min). Subjects reported to the human performance laboratory on three separate occasions. All participants completed a baseline/familiarization day of testing that included a maximal graded exercise test for the determination of aerobic capacity (VO2max), one-rep maximum (1-RM) for bench and leg press to determine 75% of 1-RM, choice reaction tests, and intermittent critical velocity familiarization. Choice reaction tests included the following: single-step audio and visual, one-tower stationary protocol, two-tower lateral protocol, three-tower multi-directional protocol, and three-tower multi-directional protocol with martial arts sticks. Subjects were randomly assigned to ingest either the supplement (SUP) or the placebo (PL) during Visit 2. Subjects were provided with the cross-over treatment on the last testing visit. Testing occurred 20 min following ingestion of both treatments. Results: Significant (p < 0.05) main effects for the SUP were observed for leg press (SUP: 13 ± 6 reps, PL: 11 ± 3 reps), perceived energy (SUP: 3.4 ± 0.9, PL: 3.1 ± 0.8), alertness (SUP: 4.0 ± 0.7, PL: 3.5 ± 0.8), focus (SUP: 4.1 ± 0.6, PL: 3.5 ± 0.8), choice reaction audio single-step (SUP: 0.92 ± 0.10 s, PL: 0.97 ± 0.11 s), choice reaction multi-direction 15 s (SUP: 1.07 ± 0.12 s, PL: 1.13 ± 0.14 s), and multi-direction for 30 s (SUP: 1.10 ± 0.11 s, PL: 1.14 ± 0.13 s). Conclusions: Ingesting the SUP before exercise significantly improved agility choice reaction performance and lower body muscular endurance, while increasing perceived energy and reducing subjective fatigue. These findings suggest that the SUP may delay fatigue during strenuous exercise.

Exercise-induced muscle damage is reduced in resistance-trained males by branched chain amino acids: a randomized, double-blind, placebo controlled study

Glyn Howatson — 2012-05-08T00:00:00Z

Background: It is well documented that exercise-induced muscle damage (EIMD) decreases musclefunction and causes soreness and discomfort. Branched-chain amino acid (BCAA)supplementation has been shown to increase protein synthesis and decrease muscle proteinbreakdown, however, the effects of BCAAs on recovery from damaging resistance trainingare unclear. Therefore, the aim of this study was to examine the effects of a BCAAsupplementation on markers of muscle damage elicited via a sport specific bout of damagingexercise in trained volunteers. Methods: Twelve males (mean +/- SD age, 23 +/- 2 y; stature, 178.3 +/- 3.6 cm and body mass, 79.6 +/- 8.4 kg)were randomly assigned to a supplement (n = 6) or placebo (n = 6) group. The damagingexercise consisted of 100 consecutive drop-jumps. Creatine kinase (CK), maximal voluntarycontraction (MVC), muscle soreness (DOMS), vertical jump (VJ), thigh circumference (TC)and calf circumference (CC) were measured as markers of muscle damage. All variables weremeasured immediately before the damaging exercise and at 24, 48, 72 and 96 h post-exercise. Results: A significant time effect was seen for all variables. There were significant group effectsshowing a reduction in CK efflux and muscle soreness in the BCAA group compared to theplacebo (P < 0.05). Furthermore, the recovery of MVC was greater in the BCAA group(P < 0.05). The VJ, TC and CC were not different between groups. Conclusion: The present study has shown that BCAA administered before and following damagingresistance exercise reduces indices of muscle damage and accelerates recovery in resistancetrainedmales. It seems likely that BCAA provided greater bioavailablity of substrate toimprove protein synthesis and thereby the extent of secondary muscle damage associatedwith strenuous resistance exercise. Clinical Trial Registration Number: NCT01529281.