Cochrane review: Whole-body cryotherapy (extreme cold air exposure) for preventing and treating muscle soreness after exercise in adults

Delayed-onset muscle soreness, or ‘DOMS’, affects many people after exercise and can impair future performance. It usually peaks one to four days after exercise and several strategies are used to overcome it. The effectiveness and safety of many of these strategies applied and promoted is unknown.

Young at heart, old at work? Relations between age, (meta-)stereotypes, self-categorization, and retirement attitudes

The aims of this study were to examine how workers' negative age stereotypes (i.e., denying older workers' ability to develop) and negative meta-stereotypes (i.e., beliefs that the majority of colleagues feel negative about older workers) are related to their attitudes towards retirement (i.e., occupational future time perspective and intention to retire), and whether the strength of these relationships is influenced by workers' self-categorization as an “older” person. Results of a study among Dutch taxi drivers provided mixed support for the hypotheses. Negative meta-stereotypes, but not negative age stereotypes, were associated with fewer perceived opportunities until retirement and, in turn, a stronger intention to retire. Self-categorization moderated the relationships between negative age (meta-)stereotypes and occupational future time perspective. However, contrary to expectations, the relations were stronger among workers with a low self-categorization as an older person in comparison with workers with a high self-categorization in this regard. Overall, results highlight the importance of psychosocial processes in the study of retirement intentions and their antecedents.

Comparing population attributable risks for heart disease across the adult lifespan in women

Background Recent estimates suggest that high body mass index (BMI), smoking, high blood pressure (BP) and physical inactivity are leading risk factors for the overall burden of disease in Australia. The aim was to examine the population attributable risk (PAR) of heart disease for each of these risk factors, across the adult lifespan in Australian women. Methods PARs were estimated using relative risks (RRs) for each of the four risk factors, as used in the Global Burden of Disease Study, and prevalence estimates from the Australian Longitudinal Study on Women's Health, in 15 age groups from 22–27 (N=9608) to 85–90 (N=3901). Results RRs and prevalence estimates varied across the lifespan. RRs ranged from 6.15 for smoking in the younger women to 1.20 for high BMI and high BP in the older women. Prevalence of risk exposure ranged from 2% for high BP in the younger women to 79% for high BMI in mid-age women. In young adult women up to age 30, the highest population risk was attributed to smoking. From age 31 to 90, PARs were highest for physical inactivity. Conclusions From about age 30, the population risk of heart disease attributable to inactivity outweighs that of other risk factors, including high BMI. Programmes for the promotion and maintenance of physical activity deserve to be a much higher public health priority for women than they are now, across the adult lifespan.

The relationship between forward head posture and cervical muscle performance in healthy individuals

Background Forward head postures (FHP) are proposed to adversely load cervical spine structures. Neck muscles provide support for the neck, and thus an imbalance in neck muscle performance could potentially contribute to the development of FHP. Previous studies have not considered the interaction of multiple muscle groups with regard to postural orientation. Given the interdependence of muscles along the cervical spine for optimal orientation and physical support of the vertebral column, the performance of a single muscle group may not accurately reflect the coordinated ability of the muscles to maintain a neutral neck posture. Purpose The purpose of this study was to investigate the relationship between FHP and the balance between the cervical extensor and flexor muscle groups in healthy individuals. We hypothesised that the magnitude of FHP would be associated with the strength and endurance performance ratios between the cervical extensor and flexor muscle groups. Methods Twenty male and 24 female volunteers were photographed in the sagittal plane wearing surface markers. The FHP of each participant was measured via the tragus-sternum marker distance over two conditions: (1)in relaxed standing and (2)during a sustained sitting task. Maximal strength (Nm) and endurance (s) performance of the extensor and flexor muscle groups were recorded at the upper (craniocervical flexion/extension (CCF/CCE)) and lower (cervicothoracic flexion/extension (CTF/CTE)) cervical regions. Muscle performance measures were expressed as extension:flexion ratios and their relation to FHP evaluated. A stepwise multiple regression analysis using backward elimination was utilised to examine the relationship between the postural measures and the muscle performance ratio measures. Separate models were used for the two different postural conditions (standing, sustained sitting). Gender was included as a constant correction factor in all regression models. Where gender was a significant variable in the model, analyses were repeated separately for males and females. Results Greater FHP in standing was significantly associated with reduced proportional CTE to CCF strength in females (R2 = 0.21, P = 0.03) and greater proportional CTE to CTF strength in males (R2 = 0.23, P = 0.03). A greater drift into FHP during sustained sitting was associated with a relative reduction in CCE endurance proportional to CTF endurance in females only (R2 = 0.27, P = 0.017). Conclusion(s) This initial study indicates that the balance in performance between the cervical flexor and extensor muscle groups may impact FHP in healthy individuals. However, the findings were inconsistent across different muscle performance ratios and gender. Larger scale studies are therefore now needed to further clarify the relationship between FHP and muscle performance. Implications The findings suggest that relative performance of the various cervical muscle groups needs to be accounted for when considering postural correction strategies in the clinical setting, as is often recommended.

A pilot education on heart failure self-management and introduction of the teach-back method to cardiac nurses in Vietnam

It is recognised that patients with chronic disease are unable to remembercorrectly information provided by health care profesionals. The teach-back method is acknowledgedas a technique to improve patients’ understanding. Yet it is not used in nursing practice in Vietnam. Objectives This study sought to examine knowledge background of heart failure among cardiac nurses, introduce a education about heart failure self-management and the teach-back method to assist teaching patients on self-care. The study also wanted to explore if a short education could benefit nurses’ knowledge so they would be qualified to deliver education to patients. Methods A pre/post-test design was employed. Cardiac nurses from 3 hospitals (Vietnam National Heart Institute, E Hospital, Huu Nghi Hospital) were invited to attend a six-hour educational session which covered both the teach-back method and heart failure self-management. Role-play with scenarios were used to reinforce educational contents. The Dutch Heart Failure Knowledge Scale was used to assess nurses’ knowledge of heart failure at baseline and after the educational session. Results 20 nurses from3 selected hospitals participated. Average age was 34.5±7.9 years and years of nursing experience was 11.6±8.3. Heart failure knowledge score at the baseline was 12.7±1.2 and post education was 13.8±1.0. There was deficiency of nurses knowledge regarding fluid restriction among heart failure people, causes of worsening heart failure. Heart failure knowledge improved significantly following the workshop (p < 0.001). All nurses achieved an overall adequate knowledge score (≥11 of the maximum 15) at the end. 100% of nurses agreed that the teach-back method was effective and could be used to educate patients about heart failure self-management. Conclusions The results of this study have shown the effectiveness of the piloteducaiton in increasing nurses’ knowledge of heart failure. The teach-back method is accepted for Vietnamese nurses to use in routine cardiac practice.

Oxidation of succinate in heart, brain, and kidney mitochondria in hypobaria and hypoxia

Exposure of rats to hypobaric stress for periods of up to 36 h caused a consistent change in the succinate-NT reductase activity of the heart mitochondria whereas there was no significant change in the activities of either succinate dehydrogenase and succinate-NT reductase of the brain and the kidney. Mitochondrial succinate dehydrogenase of the heart, the brain and the kidney was activated 2- to 7-fold with the substrate and malonate. The activations obtained with oxalate, citrate and dinitrophenol were relatively lower in comparison to succinate and malonate. Benzohydroquinone and 2-nitrophenol had no stimulatory effect on the heart, the brain and the kidney mitochondria. THE ACTIVATIONS OBTAINED WITH THE VARIOUS EFFECTORS PARTIALLY (OR COMPLETELY IN THE CASE OF SUCCINATE) REVERSED ON WASHING THE MITOCHONDRIAL SAMPLES WITH THE SUCROSE HOMOGENIZING MEDIUM. The effect of ubiquinol, which also activated the enzyme, was only partially reversed after the second preincubation with succinate in the brain and the kidney whereas in the heart the activity was fully reversed. The increased activity of succinate dehydrogenase obtained with ATP and ADP was further enhanced by Mg2+ exclusively in the brain mitochondria, suggesting the possibility of Mg2+-AIP complex as the active species. Succinate-NT reductase of the heart, the brain and the kidney mitochondria showed a high activation with ubiquinone whereas its reduced form had no stimulatory effect.

The biological functions of mouse twinfilin isoforms

The actin cytoskeleton is essential for many cellular processes, including motility, morphogenesis, endocytosis and signal transduction. Actin can exist in monomeric (G-actin) or filamentous (F-actin) form. Actin filaments are considered to be the functional form of actin, generating the protrusive forces characteristic for the actin cytoskeleton. The structure and dynamics of the actin filament and monomer pools are regulated by a large number of actin-binding proteins in eukaryotic cells. Twinfilin is an evolutionarily conserved small actin monomer binding protein. Twinfilin is composed of two ADF/cofilin-like domains, separated by a short linker and followed by a C-terminal tail. Twinfilin forms a stable, high affinity complex with ADP-G-actin, inhibits the nucleotide exchange on actin monomers, and prevents their assembly into filament ends. Twinfilin was originally identified from yeast and has since then been found from all organisms studied except plants. Not much was known about the role of twinfilin in the actin dynamics in mammalian cells before this study. We set out to unravel the mysteries still covering twinfilins functions using biochemistry, cell biology, and genetics. We identified and characterized two mouse isoforms for the previously identified mouse twinfilin-1. The new isoforms, twinfilin-2a and -2b, are generated from the same gene through alternative promoter usage. The three isoforms have distinctive expression patterns, but are similar biochemically. Twinfilin-1 is the major isoform during development and is expressed in high levels in almost all tissues examined. Twinfilin-2a is also expressed almost ubiquitously, but at lower levels. Twinfilin-2b turned out to be a muscle-specific isoform, with very high expression in heart and skeletal muscle. It seems all mouse tissues express at least two twinfilin isoforms, indicating that twinfilins are important regulators of actin dynamics in all cell and tissue types. A knockout mouse line was generated for twinfilin-2a. The mice homozygous for this knockout were viable and developed normally, indicating that twinfilin-2a is dispensable for mouse development. However, it is important to note that twinfilin-2a shows similar expression pattern to twinfilin-1, suggesting that these proteins play redundant roles in mice. All mouse isoforms were shown to be able to sequester actin filaments and have higher affinity for ADP-G-actin than ATP-G-actin. They are also able to directly interact with heterodimeric capping protein and PI(4,5)P2 similar to yeast twinfilin. In this study we also uncovered a novel function for mouse twinfilins; capping actin filament barbed ends. All mouse twinfilin isoforms were shown to possess this function, while yeast and Drosophila twinfilin were not able to cap filament barbed ends. Twinfilins localize to the cytoplasm but also to actin-rich regions in mammalian cells. The subcellular localizations of the isoforms are regulated differently, indicating that even though twinfilins biochemical functions in vitro are very similar, in vivo they can play different roles through different regulatory pathways. Together, this study show that twinfilins regulate actin filament assembly both by sequestering actin monomers and by capping filament barbed ends, and that mammals have three biochemically similar twinfilin isoforms with partially overlapping expression patterns.

Novel TBK1 truncating mutation in a familial amyotrophic lateral sclerosis patient of Chinese origin

Missense and frameshift mutations in TRAF family member-associated NF-kappa-B activator (TANK)-binding kinase 1 (TBK1) have been reported in European sporadic and familial amyotrophic lateral sclerosis (ALS) cohorts. To assess the role of TBK1 in ALS patient cohorts of wider ancestry, we have analyzed whole-exome sequence data from an Australian cohort of familial ALS (FALS) patients and controls. We identified a novel TBK1 deletion (c.1197delC) in a FALS patient of Chinese origin. This frameshift mutation (p.L399fs) likely results in a truncated protein that lacks functional domains required for adapter protein binding, as well as protein activation and structural integrity. No novel or reported TBK1 mutations were identified in FALS patients of European ancestry. This is the first report of a TBK1 mutation in an ALS patient of Asian origin and indicates that sequence variations in TBK1 are a rare cause of FALS in Australia. © 2015 Elsevier Inc.

Microneurovascular free muscle transfer with cross-over nerve grafts in facial reanimation

Microneurovascular free muscle transfer with cross-over nerve grafts in facial reanimation Loss of facial symmetry and mimetic function as seen in facial paralysis has an enormous impact on the psychosocial conditions of the patients. Patients with severe long-term facial paralysis are often reanimated with a two-stage procedure combining cross-facial nerve grafting, and 6 to 8 months later with microneurovascular (MNV) muscle transfer. In this thesis, we recorded the long-term results of MNV surgery in facial paralysis and observed the possible contributing factors to final functional and aesthetic outcome after this procedure. Twenty-seven out of forty patients operated on were interviewed, and the functional outcome was graded. Magnetic resonance imaging (MRI) of MNV muscle flaps was done, and nerve graft samples (n=37) were obtained in second stage of the operation and muscle biopsies (n=18) were taken during secondary operations.. The structure of MNV muscles and nerve grafts was evaluated using histological and immunohistochemical methods ( Ki-67, anti-myosin fast, S-100, NF-200, CD-31, p75NGFR, VEGF, Flt-1, Flk-1). Statistical analysis was performed. In our studies, we found that almost two-thirds of the patients achieved good result in facial reanimation. The longer the follow-up time after muscle transfer the weaker was the muscle function. A majority of the patients (78%) defined their quality of life improved after surgery. In MRI study, the free MNV flaps were significantly smaller than originally. A correlation was found between good functional outcome and normal muscle structure in MRI. In muscle biopsies, the mean muscle fiber diameter was diminished to 40% compared to control values. Proliferative activity of satellite cells was seen in 60% of the samples and it tended to decline with an increase of follow-up time. All samples showed intramuscular innervation. Severe muscle atrophy correlated with prolonged intraoperative ischaemia. The good long-term functional outcome correlated with dominance of fast fibers in muscle grafts. In nerve grafts, the mean number of viable axons amounted to 38% of that in control samples. The grafted nerves characterized by fibrosis and regenerated axons were thinner than in control samples although they were well vascularized. A longer time between cross facial nerve grafting and biopsy sampling correlated with a higher number of viable axons. P75Nerve Growth Factor Receptor (p75NGFR) was expressed in every nerve graft sample. The expression of p75NGFR was lower in older than in younger patients. A high expression of p75NGFR was often seen with better function of the transplanted muscle. In grafted nerve Vascular Endothelial Growth Factor (VEGF) and its receptors were expressed in nervous tissue. In conclusion, most of the patients achieved good result in facial reanimation and were satisfied with the functional outcome. The mimic function was poorer in patients with longer follow-up time. MRI can be used to evaluate the structure of the microneurovascular muscle flaps. Regeneration of the muscle flaps was still going on many years after the transplantation and reinnervation was seen in all muscle samples. Grafted nerves were characterized by fibrosis and fewer, thinner axons compared to control nerves although they were well vascularized. P75NGFR and VEGF were expressed in human nerve grafts with higher intensity than in control nerves which is described for the first time.

Ibuprofen ingestion does not affect markers of post-exercise muscle inflammation

Purpose: We investigated if oral ingestion of ibuprofen influenced leucocyte recruitment and infiltration following an acute bout of traditional resistance exercise Methods: Sixteen male subjects were divided into two groups that received the maximum over-the-counter dose of ibuprofen (1200mg d−1) or a similarly administered placebo following lower body resistance exercise. Muscle biopsies were taken from m.vastus lateralis and blood serum samples were obtained before and immediately after exercise, and at 3 and 24 h after exercise. Muscle cross-sections were stained with antibodies against neutrophils (CD66b and MPO) and macrophages (CD68). Muscle damage was assessed via creatine kinase and myoglobin in blood serum samples, and muscle soreness was rated on a ten-point pain scale. Results: The resistance exercise protocol stimulated a significant increase in the number of CD66b+ and MPO+ cells when measured 3 h post exercise. Serum creatine kinase, myoglobin and subjective muscle soreness all increased post-exercise. Muscle leucocyte infiltration, creatine kinase, myoglobin and subjective muscle soreness were unaffected by ibuprofen treatment when compared to placebo. There was also no association between increases in inflammatory leucocytes and any other marker of cellular muscle damage. Conclusion: Ibuprofen administration had no effect on the accumulation of neutrophils, markers of muscle damage or muscle soreness during the first 24 h of post-exercise muscle recovery.