Unilateral bicep curl hemodynamics: Low-pressure continuous vs high-pressure intermittent blood flow restriction.

Light-load exercise training with blood flow restriction (BFR) increases muscle strength and size. However, the hemodynamics of BFR exercise appear elevated compared with non-BFR exercise. This questions the suitability of BFR in special/clinical populations. Nevertheless, hemodynamics of standard prescription protocols for BFR and traditional heavy-load exercise have not been compared. We investigated the hemodynamics of two common BFR exercise methods and two traditional resistance exercises. Twelve young males completed four unilateral elbow flexion exercise trials in a balanced, randomized crossover design: (a) heavy load [HL; 80% one-repetition maximum (1-RM)]; (b) light load (LL; 20% 1-RM); and two other light-load trials with BFR applied (c) continuously at 80% resting systolic blood pressure (BFR-C) or (d) intermittently at 130% resting systolic blood pressure (BFR-I). Hemodynamics were measured at baseline, during exercise, and for 60-min post-exercise. Exercising heart rate, blood pressure, cardiac output, and rate-pressure product were significantly greater for HL and BFR-I compared with LL. The magnitude of hemodynamic stress for BFR-C was between that of HL and LL. These data show reduced hemodynamics for continuous low-pressure BFR exercise compared with intermittent high-pressure BFR in young healthy populations. BFR remains a potentially viable method to improve muscle mass and strength in special/clinical populations.

Including arm exercise during a cold water immersion recovery better assists restoration of sprint cycling performance.

Sprint (high-intensity) exercise performance is reduced when immediately preceded by cold water immersion (CWI). We aimed to investigate whether this performance effect could be attenuated by combining an active recovery (arm exercise) with hip-level CWI, and whether this attenuation may be related to an effect on core temperature (Tcore ). Participants (n = 8) completed three Wingate tests before (Ex1) and after (Ex2) four different 30-min recovery interventions: CWI at 15 °C (CW15), arm exercise during CWI at 15 °C (CW15+AE), arm exercise during thermoneutral immersion at 34 °C (TW34+AE) and non-immersed arm exercise (AE). After AE and TW34+AE, performance during Ex2 was not different from Ex1; while after CW15+AE and CW15, performance was reduced by 4.9% and 7.6%, respectively. Arm exercise maintained Tcore during recovery in CW15+AE, while it declined to a larger extent upon commencement of Ex2 (-0.9 °C) when compared with CW15 (-0.6 °C). This suggests similar leg muscle cooling during recovery in CW15 and CW15+AE. Without any other significant effects (e.g., on blood lactate), these data suggest that the improvement in sprint performance following an active CWI recovery, over CWI alone, may be related to maintained Tcore and its effect on neurophysiological mechanisms that drive muscle activation, but not by reduced muscle cooling.

Objectively measured muscle fatigue in Crohn's disease: correlation with self-reported fatigue and associated factors for clinical application.

BACKGROUND & AIMS: The association of fatigue with decreased physical performance and underlying mechanisms are poorly understood in Crohn's disease (CD). We aimed to measure and compare self-reported fatigue with skeletal muscle fatigue in CD subjects and healthy controls, and to identify associated factors that may be amenable to change. METHODS: Demographic and clinical data were collected and fatigue assessed using the Fatigue Impact Scale (FIS) in 27 consecutive CD patients and 22 matched healthy controls. Circulating cytokines and growth factors were measured. The rate of quadriceps muscle fatigue was assessed using an isokinetic dynamometer as the decrement of force with 30 contractions performed over a 5-minute period. RESULTS: Compared with healthy controls, CD patients reported greater levels of fatigue (mean global FIS score 45.3 vs 10.5, physical dimension score 12.3 vs 2.7 respectively; each p<0.01) and muscle fatigue (-5.2 vs -1.3 Nm min(-1); p<0.05). The two indices were correlated (r = -0.52 in CD; p<0.01). Patients with CD had lower mean serum IGF-1 levels (16.1 vs 25.4 pmol/L, p<0.01) and higher oxidative stress (TBARS assay 4.3 vs 3.9 µM, p<0.05). On multivariate analysis, low serum vitamin D, IGF-1 and magnesium, and higher IL-6 levels were associated with increased muscle fatigue (all p ≤ 0.05). CONCLUSION: Subjects with CD had more muscle fatigue than matched healthy controls and this correlated well with self-reported fatigue. Of circulating factors that were independently associated with increased muscle fatigue, vitamin D, magnesium and IGF-1 could be targeted in future studies to reduce fatigue and improve physical performance.

Assessing the value of matrix metalloproteinase 9 (MMP9) in improving the appropriateness of referrals for colorectal cancer.

BACKGROUND: A blood test may be an effective means of improving the appropriateness of referrals for symptomatic patients referred to specialist colorectal clinics. We evaluated the accuracy of a serum matrix metalloproteinase (MMP9) test in indicating colorectal cancer or its precursor conditions in a symptomatic population. METHODS: Patients aged over 18, referred urgently or routinely to secondary care following primary care presentation with colorectal symptoms completed a questionnaire and provided a blood sample for serum MMP9 estimation. Univariate analysis and logistic regression modelling investigated the association between presenting symptoms, MMP9 measurements and the diagnostic outcome of patient investigations, in order to derive the combination of factors which best predicted a high risk of malignancy. RESULTS: Data were analysed for 1002 patients. Forty-seven cases of neoplasia were identified. Age, male gender, absence of anal pain, diabetes, blood in stools, urgent referral, previous bowel polyps and previous bowel cancer were significantly associated with neoplasia. Matrix metalloproteinase 9 measurements were not found to be associated with significant colorectal pathology. CONCLUSION: This study, despite robust sampling protocols, showed no clear association between MMP9 and colorectal neoplasia. Matrix metalloproteinase 9 therefore appears to have little value as a tool to aid referral decisions in the symptomatic population.

The effect of seeking consent on the representativeness of patient cohorts: iron-deficiency anaemia and colorectal cancer.

AIM: The study aimed to establish the level of selection bias that may occur should individual patient consent be sought, by comparing characteristics of consenters and nonconsenters to a request for access to medical records within a cohort of patients diagnosed with iron-deficiency anaemia (IDA). METHOD: A cohort study and cross-sectional survey was carried out of consent preferences that compared the sociodemographic characteristics of patients providing or not providing consent for access to their records, the consent rates by participant subgroup and the predictors of consent/nonconsent. RESULTS: Of 599 patients mailed requesting consent for access to their medical records, 425 (71.0%) responses were received. Of the valid responses, explicit consent was granted by 371 (62.7%) respondents, with 47 (7.9%) refusals. The characteristics of consenters and nonconsenters differed with regard to age, gender and deprivation quartile. Nonconsent was associated with younger age (40-60 years vs 60 + years; bivariate OR = 2.84; 95% CI = 2.01-4.02), female gender (OR = 1.62; 95% CI = 1.13-2.34) and being socioeconomically deprived (OR = 1.61; 95% CI = 1.15-2.26). CONCLUSION: The current research governance framework demonstrates a conflict between protecting the rights of the individual and the development of a sound research base to improve the delivery of healthcare services for society as a whole. If epidemiological research includes data only from individuals who have given consent for access to their records, the resulting selection bias may have consequences for the scientific validity and generalizability of research findings, and ultimately the quality of patient care.

The use of herbal medicines by people with cancer: a cross-sectional survey.

BACKGROUND: A large proportion of cancer patients are estimated to use herbal medicines, but data to substantiate this are lacking. This study aimed to investigate the prevalence of herbal medicine use among cancer patients in the West Midlands, and determine the characteristics predicting herbal medicine use. METHODS: A cross-sectional survey of oncology patients (n=1498) being followed up at a hospital in Coventry was undertaken. Recipients were asked about herbal medicine use since their cancer diagnosis, and the association between sociodemographic and cancer-related characteristics and herbal medicine use was evaluated. RESULTS: A total of 1134 responses were received (75.7%). The prevalence of herbal medicine use was 19.7% (95% CI: 17.4-22.1; n=223). Users were more likely to be affluent, female, and aged under 50 years. Usage increased with time since cancer diagnosis (X(2) for trend=4.63; P=0.031). A validation data set, derived from a survey of oncology patients in Birmingham (n=541) with differing socioeconomic characteristics showed no significant difference in estimated prevalence (16.6%; 95% CI: 11.9-22.2). CONCLUSION: A substantial number of people with cancer are likely to be taking herbal medicines. Understanding the self-medication behaviours of these individuals is essential if health-care professionals are to support treatment adherence and avoid unwanted pharmacological interactions.

The use of herbal medicines by people with cancer in the UK: a systematic review of the literature.

BACKGROUND AND AIM: Little is known about the use of herbal medicines by people living with cancer in the UK. This systematic review aimed to estimate the prevalence of herbal medicine use by this group, the characteristics of users, factors motivating use, and attitudes towards herbal remedies. DESIGN AND METHODS: Fifteen electronic databases were searched. People who were research-active in the field were contacted and asked about further published or unpublished work. All studies identified as relevant to the purpose of the review were assessed. Searches were not restricted by publication type or date. RESULTS: Of 1288 unique references identified, 11 met the eligibility criteria. Studies were excluded where research had been conducted outside the UK; where information on herbal medicine use was not differentiated from that relating to complementary and alternative therapies more broadly, and where neither prevalence of use nor information on user characteristics was included. Prevalence estimates ranged from 3.1 to 24.9%. Most studies did not obtain information specifically on herbal medicines and only one examined the characteristics and motivations of users of herbal medicines as distinct from complementary and alternative therapies in general. CONCLUSION: The high degree of heterogeneity of methodology, sample selection and characteristics, and research design resulted in a wide range of estimates of prevalence. Well-designed research is needed to define the evidence base about the herbal medicines taken by people with cancer in the UK, the reasons for use, knowledge about possible effects and potential risks, and where people seek information.

Functional and histological characteristics of skeletal muscle and the effects of leptin in the genetically obese (ob/ob) mouse.

BACKGROUND: Skeletal muscle mass in genetically obese (ob/ob) mice displays a reduced mass compared with their normal lean counterpart mice. However, the functional capacity of the available skeletal muscle mass in these animals has not yet been determined. OBJECTIVE: To investigate the properties of skeletal muscle in ob/ob mice and determine the effects of leptin administration on skeletal muscle in these mice. METHODS: Following 4 weeks of i.p. leptin administration (or control treatment) anaesthetized ob/ob and lean mice had their extensor digitorum longus and soleus muscles removed, and standard measures of isometric contractile properties and fatigability were performed. Histochemistry was used to determine fibre type proportions and individual fibre areas of all muscles. RESULTS: Leptin had no effect on the morphology or function of ob/ob skeletal muscle despite reducing body mass in ob/ob mice. Force production was unaltered in obese mice. However, a significant prolongation of contraction and relaxation times were evident. Obese skeletal muscle was also more fatigue resistant. Fibre proportions displayed a more slow type profile in ob/ob skeletal muscle, and in conjunction with previous work a reduced ability to hypertrophy. CONCLUSION: Skeletal muscle from obese mice is morphologically and functionally different from lean mouse skeletal muscle. Obese muscle is very similar to skeletal muscle from aged mice, and the specific contractile properties examined appear to be determined by the fibre make-up of these muscles.

Effects of resistance training on bone parameters in young and mature rats.

1. Osteoporosis is a major public health problem that is predicted to worsen over the next decade and preventative strategies that increase bone strength have become the focus of substantial research. 2. Although mechanical load is a primary factor in the acquisition and maintenance of skeletal tissue, the type of exercise used and when in life it is most effectively prescribed remain inconclusive. 3. The present study compared 10 weeks of resistance training in both young and mature female Sprague-Dawley rats and measured bone density and body composition by dual energy X-ray absorptiometry and biomechanical properties by three point bending tests of the tibia and femur. 4. No significant differences were observed for any of the bone parameters when comparing exercise and control groups at either age. This was despite using a comparable training protocol to that in humans and using loads of approximately 150% bodyweight. 5. The present study concludes that more intensive work programmes of resistance training or different outcome measures are required when using animal models for skeletal research.

Muscle metabolites and performance during high-intensity, intermittent exercise.

Six men were studied during four 30-s "all-out" exercise bouts on an air-braked cycle ergometer. The first three exercise bouts were separated by 4 min of passive recovery; after the third bout, subjects rested for 4 min, exercised for 30 min at 30-35% peak O2 consumption, and rested for a further 60 min before completing the fourth exercise bout. Peak power and total work were reduced (P < 0. 05) during bout 3 [765 +/- 60 (SE) W; 15.8 +/- 1.0 kJ] compared with bout 1 (1,168 +/- 55 W, 23.8 +/- 1.2 kJ), but no difference in exercise performance was observed between bouts 1 and 4 (1,094 +/- 64 W, 23.2 +/- 1.4 kJ). Before bout 3, muscle ATP, creatine phosphate (CP), glycogen, pH, and sarcoplasmic reticulum (SR) Ca2+ uptake were reduced, while muscle lactate and inosine 5'-monophosphate were increased. Muscle ATP and glycogen before bout 4 remained lower than values before bout 1 (P < 0.05), but there were no differences in muscle inosine 5'-monophosphate, lactate, pH, and SR Ca2+ uptake. Muscle CP levels before bout 4 had increased above resting levels. Consistent with the decline in muscle ATP were increases in hypoxanthine and inosine before bouts 3 and 4. The decline in exercise performance does not appear to be related to a reduction in muscle glycogen. Instead, it may be caused by reduced CP availability, increased H+ concentration, impairment in SR function, or some other fatigue-inducing agent.

A method for measuring sarcoplasmic reticulum calcium uptake in the skeletal muscle using Fura-2.

We have presented an assay for measuring the rate of sarcoplasmic reticulum (SR) Ca2+ uptake and Ca2+ release in skeletal muscle homogenates using the fluorescent Ca2+ probe Fura-2. Using this assay, we investigated the effects of an elevated temperature (40 degrees C) and lowered pH (6.8), two factors proposed to be involved in skeletal muscle fatigue, on SR Ca2+ uptake. The EDL muscle was found to have a higher rate of Ca2+ uptake than the soleus (34%). Exposure of the muscles to a raised temperature, but not a reduced pH, resulted in a reduction in the rate of Ca2+ uptake in both the EDL and soleus homogenates. This uptake process was blocked by cyclopiazonic acid (CPA) a specific inhibitor of the major transport protein of the sarcoplasmic reticulum, the Ca(2+)-ATPase. Calcium release was induced using AgNO3 after loading of the vesicles during the uptake process. It was found that AgNO3 was only effective in producing Ca2+ release in the EDL muscles. The soleus muscles did not release Ca2+ under varying [Mg2+] or with Hg2+ substitution for Ag+, suggesting that fast- and slow-twitch muscle fibres require different conditions for maximum Ca2+ release, or that different isoforms of the Ca2+ release channels are present in the different fibres.

Rehabilitation of lower limb amputees and some implications for surgical management.

Aspects of peri-operative management, amputation level and rehabilitation of the lower limb amputee are reported in the context of a review of a rehabilitation service for amputees which includes an integrated prosthetic service. Two hundred admissions were reviewed and some complex cases described. It is concluded that: a very close liaison between the surgeon and the rehabilitation team (ideally with preoperative consultation) is in the patient's best interests; any person previously walking (or a potential walker) should be considered for a trial of prosthetic walking; an integrated prosthetic service enhances the efficiency of the rehabilitation service; and that modification of the current Artificial Limb Scheme to allow manufacture of first definitive limbs in prosthetic rehabilitation units would further enhance service to patients.