Presence of Observers Increases One Repetition Maximum in College-age Males and Females

Purpose: To determine if the presence of observers affects muscular strength performance in college-age males and females. Methods: Twenty-five women and 24 men participated in the study. Two counter-balanced trials were performed in which participants completed 1-RM tests in bench press and leg press. During one trial, two members of the opposite gender observed the 1-RM tests. During the other trial there were no observers, other than the tester. Results: 1-RM for females increased 3.4±0.8 lbs on bench press (p\u3c.001) and increased 9.2±3.8 lbs on leg press (p=.025) when observers were present. 1-RM for males increased 4.2±1.1 lbs on bench press (p=.001) and increased 18.8±5.2 lbs on leg press (p=.002) with observers present. There was no difference in the percent increase in 1-RM between males and females for either leg press (p=.71) or bench press (p=.08). Conclusion: College-age males and females lifted more weight during a 1-RM test when observers were present

Self-estimation of Body Fat is More Accurate in College-age Males Compared to Females

Objective: To determine the effect of gender on the ability to accurately estimate one’s own body fat percentage. Participants: Fifty-five college-age males and 99 college-age females Methods: Participants estimated their own body fat percent before having their body composition measured using a BOD POD. Participants also completed a modified Social Physique Anxiety Scale (SPAS). Results: Estimated body fat was significantly lower compared to measured body fat percent in females (26.8±5.6% vs. 30.2±7.0%, p\u3c0.001) but not in males (16.8±6.8% vs. 18.1±8.3%, p=0.09). The mean difference between estimated and measured body fat was significantly higher for females compared to males (p\u3c0.001). There was a moderate, significant correlation found between measured body fat percent and SPAS score for males (r=0.331, p=0.014) and females (r=.427, p\u3c0.001). Conclusions: Males estimated their body fat percent more accurately than females. Despite these findings, 62% of males and 76% of females underestimated their body fat

Type of Encouragement Influences Peak Muscle Force in College-Age Women

Purpose: To investigate if the type of encouragement during a maximal voluntary isometric contraction (MVIC) had an influence on peak muscle force in strength-trained versus untrained collegiate women. Methods: Eleven strength-trained (20.4 + 1 yr) and twelve untrained (20.8 + 1 yr) women participated in three, five-second MVICs of seated knee extension. The three trials consisted of verbal only encouragement, verbal + visual encouragement, and verbal + pain avoidance encouragement. In all three trials, the participants received the same verbal encouragement. Trials were counterbalanced to minimize any possible order effects. A repeated measure ANOVA was used to analyze data. Any significant main effects were further analyzed using Tukey post hoc tests. Results: There was no interaction between training status and encouragement type for all subjects F(2,42) = 1.5474, p = 0.22). For all subjects, a main effect for encouragement type was detected (F(2,42) = 6.616, p \u3c0.05) with significant differences found in MVIC between the verbal encouragement and verbal + visual feedback (99.5±29 ft-lbs and 115.6±29 ft-lbs, p\u3c0.01). No significant differences were found between the verbal only and the addition of pain avoidance (99.5±29 ft-lbs and 109.9±26.3 ft-lbs, p=0.069) or the visual and pain avoidance trials (115.6±29 ft-lbs and 109.9±26 ft-lbs, p=0.43). Conclusion: In this study, training status did not significantly influence the response to type of encouragement. Individuals produced the most force during a MVIC with verbal and visual encouragement. The incorporation of verbal encouragement and visual feedback is an important factor in eliciting peak force in college-aged women. This may have important implications in training and rehabilitation models that incorporate resistive loading of the skeletal muscles

Upper Body Muscular Activation during Variations of Push-Ups in Healthy Men

International Journal of Exercise Science 6(4) : 278-288, 2013. The purpose of this study was to assess neural activity for upper body musculature in college-age men during repetitions of a conventional pushup or a Perfect PushupTM. Eighteen healthy men (21.6±1 yr, 182.5±7 cm, 87.4±15 kg) completed five repetitions of a conventional pushup and Perfect PushupTM while using a wide hand base of support for the upper body. Body position, hand placement, and cadence of the pushup were standardized. Root mean square electromyography (RMS-EMG, mV/Sec) was collected for the triceps brachii (TB), pectoralis major (PM), serratus anterior (SA), and posterior deltoid (PD) during all repetitions. RMS-EMG values were normalized to a maximal voluntary isometric contraction in the pushup position (%MVICPU). For each muscle, %MVICPU for repetitions 1, 3, and 5 were analyzed for differences due to type of push-up. No differences in %MVICPU due to type ofpush-up for the TB (p=0.079) or the SA (p=0.45) were detected. The Perfect PushupTM increased %MVICPU compared to the conventional pushup (44%, p\u3c0.05). Additionally, the Perfect PushupTM increased %MVICPU by the third repetition (p\u3c0.05) while the conventional pushup did not until the 5th repetition. The conventional pushup activated more PD (76%, p\u3c0.05). The type of push-up that requires the greatest neural activity for a given number of repetitions should result in improved adaptations. The Perfect PushupTM was superior for activating the pectoralis major while individuals would elicit more neural activation in the posterior deltoid by conventional push-ups. Trainers and rehabilitation specialists should consider these data when attempting to train or isolate upper body skeletal muscles using a push-up movement

Variation in the organization and subunit composition of the mammalian pyruvate dehydrogenase complex E2/E3BP core assembly

The final version of this article is available at the link below.Crucial to glucose homoeostasis in humans, the hPDC (human pyruvate dehydrogenase complex) is a massive molecular machine comprising multiple copies of three distinct enzymes (E1–E3) and an accessory subunit, E3BP (E3-binding protein). Its icosahedral E2/E3BP 60-meric ‘core’ provides the central structural and mechanistic framework ensuring favourable E1 and E3 positioning and enzyme co-operativity. Current core models indicate either a 48E2+12E3BP or a 40E2+20E3BP subunit composition. In the present study, we demonstrate clear differences in subunit content and organization between the recombinant hPDC core (rhPDC; 40E2+20E3BP), generated under defined conditions where E3BP is produced in excess, and its native bovine (48E2+12E3BP) counterpart. The results of the present study provide a rational basis for resolving apparent differences between previous models, both obtained using rhE2/E3BP core assemblies where no account was taken of relative E2 and E3BP expression levels. Mathematical modelling predicts that an ‘average’ 48E2+12E3BP core arrangement allows maximum flexibility in assembly, while providing the appropriate balance of bound E1 and E3 enzymes for optimal catalytic efficiency and regulatory fine-tuning. We also show that the rhE2/E3BP and bovine E2/E3BP cores bind E3s with a 2:1 stoichiometry, and propose that mammalian PDC comprises a heterogeneous population of assemblies incorporating a network of E3 (and possibly E1) cross-bridges above the core surface.This work was partly supported by EPSRC (under grants GR/R99393/01 and EP/C015452/1)

Critical Structural and Functional Roles for the N-Terminal Insertion Sequence in Surfactant Protein B Analogs

Surfactant protein B (SP-B; 79 residues) belongs to the saposin protein superfamily, and plays functional roles in lung surfactant. The disulfide cross-linked, N- and C-terminal domains of SP-B have been theoretically predicted to fold as charged, amphipathic helices, suggesting their participation in surfactant activities. Earlier structural studies with Mini-B, a disulfide-linked construct based on the N- and C-terminal regions of SP-B (i.e., approximately residues 8-25 and 63-78), confirmed that these neighboring domains are helical; moreover, Mini-B retains critical in vitro and in vivo surfactant functions of the native protein. Here, we perform similar analyses on a Super Mini-B construct that has native SP-B residues (1-7) attached to the N-terminus of Mini-B, to test whether the N-terminal sequence is also involved in surfactant activity.FTIR spectra of Mini-B and Super Mini-B in either lipids or lipid-mimics indicated that these peptides share similar conformations, with primary alpha-helix and secondary beta-sheet and loop-turns. Gel electrophoresis demonstrated that Super Mini-B was dimeric in SDS detergent-polyacrylamide, while Mini-B was monomeric. Surface plasmon resonance (SPR), predictive aggregation algorithms, and molecular dynamics (MD) and docking simulations further suggested a preliminary model for dimeric Super Mini-B, in which monomers self-associate to form a dimer peptide with a "saposin-like" fold. Similar to native SP-B, both Mini-B and Super Mini-B exhibit in vitro activity with spread films showing near-zero minimum surface tension during cycling using captive bubble surfactometry. In vivo, Super Mini-B demonstrates oxygenation and dynamic compliance that are greater than Mini-B and compare favorably to full-length SP-B.Super Mini-B shows enhanced surfactant activity, probably due to the self-assembly of monomer peptide into dimer Super Mini-B that mimics the functions and putative structure of native SP-B

Grifonin-1: A Small HIV-1 Entry Inhibitor Derived from the Algal Lectin, Griffithsin

Background: Griffithsin, a 121-residue protein isolated from a red algal Griffithsia sp., binds high mannose N-linked glycans of virus surface glycoproteins with extremely high affinity, a property that allows it to prevent the entry of primary isolates and laboratory strains of T- and M-tropic HIV-1. We used the sequence of a portion of griffithsin's sequence as a design template to create smaller peptides with antiviral and carbohydrate-binding properties. Methodology/Results: The new peptides derived from a trio of homologous β-sheet repeats that comprise the motifs responsible for its biological activity. Our most active antiviral peptide, grifonin-1 (GRFN-1), had an EC50 of 190.8±11.0 nM in in vitro TZM-bl assays and an EC50 of 546.6±66.1 nM in p24gag antigen release assays. GRFN-1 showed considerable structural plasticity, assuming different conformations in solvents that differed in polarity and hydrophobicity. Higher concentrations of GRFN-1 formed oligomers, based on intermolecular β-sheet interactions. Like its parent protein, GRFN-1 bound viral glycoproteins gp41 and gp120 via the N-linked glycans on their surface. Conclusion: Its substantial antiviral activity and low toxicity in vitro suggest that GRFN-1 and/or its derivatives may have therapeutic potential as topical and/or systemic agents directed against HIV-1

The combined influence of distance and neighbourhood deprivation on Emergency Department attendance in a large English population: a retrospective database study

YesThe frequency of visits to Emergency Departments (ED) varies greatly between populations. This may reflect variation in patient behaviour, need, accessibility, and service configuration as well as the complex interactions between these factors. This study investigates the relationship between distance, socio-economic deprivation, and proximity to an alternative care setting (a Minor Injuries Unit (MIU)), with particular attention to the interaction between distance and deprivation. It is set in a population of approximately 5.4 million living in central England, which is highly heterogeneous in terms of ethnicity, socio-economics, and distance to hospital. The study data set captured 1,413,363 ED visits made by residents of the region to National Health Service (NHS) hospitals during the financial year 2007/8. Our units of analysis were small units of census geography having an average population of 1,545. Separate regression models were made for children and adults. For each additional kilometre of distance from a hospital, predicted child attendances fell by 2.2% (1.7%-2.6% p<0.001) and predicted adult attendances fell by 1.5% (1.2% -1.8%, p<0.001). Compared to the least deprived quintile, attendances in the most deprived quintile more than doubled for children (incident rate ratio (IRR) = 2.19, (1.90-2.54, p<0.001)) and adults (IRR 2.26, (2.01-2.55, p<0.001)). Proximity of an MIU was significant and both adult and child attendances were greater in populations who lived further away from them, suggesting that MIUs may reduce ED demand. The interaction between distance and deprivation was significant. Attendance in deprived neighbourhoods reduces with distance to a greater degree than in less deprived ones for both adults and children. In conclusion, ED use is related to both deprivation and distance, but the effect of distance is modified by deprivation