975 resultados para CARDIAC-MUSCLE


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We investigated functional, morphological and molecular adaptations to strength training exercise and cold water immersion (CWI) through two separate studies. In one study, 21 physically active men strength trained for 12 weeks (2 d⋅wk–1), with either 10 min of CWI or active recovery (ACT) after each training session. Strength and muscle mass increased more in the ACT group than in the CWI group (P<0.05). Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P<0.05) but not the CWI group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed by CWI or ACT. Muscle biopsies were collected before and 2, 24 and 48 h after exercise. The number of satellite cells expressing neural cell adhesion molecule (NCAM) (10−30%) and paired box protein (Pax7)(20−50%) increased 24–48 h after exercise with ACT. The number of NCAM+ satellitecells increased 48 h after exercise with CWI. NCAM+- and Pax7+-positivesatellite cell numbers were greater after ACT than after CWI (P<0.05). Phosphorylation of p70S6 kinaseThr421/Ser424 increased after exercise in both conditions but was greater after ACT (P<0.05). These data suggest that CWI attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered.

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Equine metabolic syndrome is characterized by obesity and insulin resistance (IR). Currently, there is no effective pharmacological treatment for this insidious disease. Glucose uptake is mediated by a family of glucose transporters (GLUT), and is regulated by insulin-dependent and -independent pathways, including 5-AMP-activated protein kinase (AMPK). Importantly, the activation of AMPK, by 5-aminoimidazole- 4-carboxamide-1-D-ribofuranoside (AICAR) stimulates glucose uptake in both healthy and diabetic humans. However, whether AICAR promotes glucose uptake in horses has not been established. It is hypothesized that AICAR administration would enhance glucose transport in equine skeletal muscle through AMPK activation. In this study, the effect of an intravenous AICAR infusion on blood glucose and insulin concentrations, as well as on GLUT expression and AMPK activation in equine skeletal muscle (quantified by Western blotting) was examined. Upon administration, plasma AICAR rapidly reached peak concentration. Treatment with AICAR resulted in a decrease (P < 0.05) in blood glucose and an increase (P < 0.05) in insulin concentration without a change in lactate concentration. The ratio of phosphorylated to total AMPK was increased (P < 0.05) in skeletal muscle. While GLUT4 and GLUT1 protein expression remained unchanged, GLUT8 was increased (P < 0.05) following AICAR treatment. Up-regulation of GLUT8 protein expression by AICAR suggests that this novel GLUT isoform plays an important role in equine muscle glucose transport. In addition, the data suggest that AMPK activation enhances pancreatic insulin secretion. Collectively, the findings suggest that AICAR acutely promotes muscle glucose uptake in healthy horses and thus its therapeutic potential for managing IR requires investigation.

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Purpose We determined the effect of reduced muscle glycogen availability on cellular pathways regulating mitochondrial biogenesis and substrate utilization after a bout of resistance exercise. Methods Eight young, recreationally trained men undertook a glycogen depletion protocol of one-leg cycling to fatigue (LOW), while the contralateral (control) leg rested (CONT). Following an overnight fast, subjects completed 8 sets of 5 unilateral leg press repetitions (REX) at 80 % 1 Repetition Maximum (1RM) on each leg. Subjects consumed 500 mL protein/CHO beverage (20 g whey + 40 g maltodextrin) upon completion of REX and 2 h later. Muscle biopsies were obtained at rest and 1 and 4 h after REX in both legs. Results Resting muscle glycogen was higher in the CONT than LOW leg (~384 ± 114 vs 184 ± 36 mmol kg−1 dry wt; P < 0.05), and 1 h and 4 h post-exercise (P < 0.05). Phosphorylation of p53Ser15 increased 1 h post-exercise in LOW (~115 %, P < 0.05) and was higher than CONT at this time point (~87 %, P < 0.05). p38MAPKThr180/Tyr182 phosphorylation increased 1 h post-exercise in both CONT and LOW (~800–900 %; P < 0.05) but remained above rest at 4 h only in CONT (~585 %, P < 0.05; different between legs P < 0.05). Peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) mRNA was elevated 4 h post-exercise in LOW (~200 %, P < 0.05; different between legs P < 0.05). There were no changes in Fibronectin type III domain-containing protein 5 (FNDC5) mRNA for CONT or LOW legs post-exercise. Conclusion Undertaking resistance exercise with low glycogen availability may enhance mitochondrial-related adaptations through p53 and PGC-1α-mediated signalling.

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Background Recovery strategies are often usedwith the intention of preventing orminimisingmuscle soreness after exercise. Whole-body cryotherapy, which involves a single or repeated exposure(s) to extremely cold dry air (below -100 °C) in a specialised chamber or cabin for two to four minutes per exposure, is currently being advocated as an effective intervention to reduce muscle soreness after exercise. Objectives To assess the effects (benefits and harms) of whole-body cryotherapy (extreme cold air exposure) for preventing and treating muscle soreness after exercise in adults. Search methods We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, the British Nursing Index and the Physiotherapy Evidence Database. We also searched the reference lists of articles, trial registers and conference proceedings, handsearched journals and contacted experts. The searches were run in August 2015. Selection criteria We aimed to include randomised and quasi-randomised trials that compared the use of whole-body cryotherapy (WBC) versus a passive or control intervention (rest, no treatment or placebo treatment) or active interventions including cold or contrast water immersion, active recovery and infrared therapy for preventing or treating muscle soreness after exercise in adults. We also aimed to include randomised trials that compared different durations or dosages of WBC. Our prespecified primary outcomes were muscle soreness, subjective recovery (e.g. tiredness, well-being) and adverse effects. Data collection and analysis Two review authors independently screened search results, selected studies, assessed risk of bias and extracted and cross-checked data. Where appropriate, we pooled results of comparable trials. The random-effects model was used for pooling where there was substantial heterogeneity.We assessed the quality of the evidence using GRADE. Main results Four laboratory-based randomised controlled trials were included. These reported results for 64 physically active predominantly young adults (mean age 23 years). All but four participants were male. Two trials were parallel group trials (44 participants) and two were cross-over trials (20 participants). The trials were heterogeneous, including the type, temperature, duration and frequency of WBC, and the type of preceding exercise. None of the trials reported active surveillance of predefined adverse events. All four trials had design features that carried a high risk of bias, potentially limiting the reliability of their findings. The evidence for all outcomes was classified as ’very low’ quality based on the GRADE criteria. Two comparisons were tested: WBC versus control (rest or no WBC), tested in four studies; and WBC versus far-infrared therapy, also tested in one study. No studies compared WBC with other active interventions, such as cold water immersion, or different types and applications of WBC. All four trials compared WBC with rest or no WBC. There was very low quality evidence for lower self-reported muscle soreness (pain at rest) scores after WBC at 1 hour (standardised mean difference (SMD) -0.77, 95% confidence interval (CI) -1.42 to -0.12; 20 participants, 2 cross-over trials); 24 hours (SMD -0.57, 95%CI -1.48 to 0.33) and 48 hours (SMD -0.58, 95% CI -1.37 to 0.21), both with 38 participants, 2 cross-over studies, 1 parallel group study; and 72 hours (SMD -0.65, 95% CI -2.54 to 1.24; 29 participants, 1 cross-over study, 1 parallel group study). Of note is that the 95% CIs also included either no between-group differences or a benefit in favour of the control group. One small cross-over trial (9 participants) found no difference in tiredness but better well-being after WBC at 24 hours post exercise. There was no report of adverse events. One small cross-over trial involving nine well-trained runners provided very low quality evidence of lower levels of muscle soreness after WBC, when compared with infrared therapy, at 1 hour follow-up, but not at 24 or 48 hours. The same trial found no difference in well-being but less tiredness after WBC at 24 hours post exercise. There was no report of adverse events. Authors’ conclusions There is insufficient evidence to determine whether whole-body cryotherapy (WBC) reduces self-reportedmuscle soreness, or improves subjective recovery, after exercise compared with passive rest or no WBC in physically active young adult males. There is no evidence on the use of this intervention in females or elite athletes. The lack of evidence on adverse events is important given that the exposure to extreme temperature presents a potential hazard. Further high-quality, well-reported research in this area is required and must provide detailed reporting of adverse events.

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Rationale, aims and objectives: Patients with both cardiac disease and diabetes have poorer health outcomes than patients with only one chronic condition. While evidence indicates that internet based interventions may improve health outcomes for patients with a chronic disease, there is no literature on internet programs specific to cardiac patients with comorbid diabetes. Therefore this study aimed to develop a specific web-based program, then to explore patients’ perspectives on the usefulness of a new program. Methods: The interpretive approach using semi-structured interviews on a purposive sample of eligible patients with type 2 diabetes and a cardiac condition in a metropolitan hospital in Brisbane, Australia. Thematic analysis was undertaken to describe the perceived usefulness of a newly developed Heart2heart webpage. Results: Themes identified included confidence in hospital health professionals and reliance on doctors to manage conditions. Patients found the webpage useful for managing their conditions at home. Conclusions: The new Heart2heart webpage provided a positive and useful resource. Further research on to determine the potential influence of this resource on patients’ self-management behaviours is paramount. Implications for practice include using multimedia strategies for providing information to patients’ comorbidities of cardiac disease and type 2 diabetes, and further development on enhancement of such strategies

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BACKGROUND Many patients presenting to the emergency department (ED) for assessment of possible acute coronary syndrome (ACS) have low cardiac troponin concentrations that change very little on repeat blood draw. It is unclear if a lack of change in cardiac troponin concentration can be used to identify acutely presenting patients at low risk of ACS. METHODS We used the hs-cTnI assay from Abbott Diagnostics, which can detect cTnI in the blood of nearly all people. We identified a population of ED patients being assessed for ACS with repeat cTnI measurement who ultimately were proven to have no acute cardiac disease at the time of presentation. We used data from the repeat sampling to calculate total within-person CV (CV(T)) and, knowing the assay analytical CV (CV(A)), we could calculate within-person biological variation (CV(i)), reference change values (RCVs), and absolute RCV delta cTnI concentrations. RESULTS We had data sets on 283 patients. Men and women had similar CV(i) values of approximately 14%, which was similar at all concentrations <40 ng/L. The biological variation was not dependent on the time interval between sample collections (t = 1.5-17 h). The absolute delta critical reference change value was similar no matter what the initial cTnI concentration was. More than 90% of subjects had a critical reference change value <5 ng/L, and 97% had values of <10 ng/L. CONCLUSIONS With this hs-cTnI assay, delta cTnI seems to be a useful tool for rapidly identifying ED patients at low risk for possible ACS.

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IMPORTANCE Patients with chest pain represent a high health care burden, but it may be possible to identify a patient group with a low short-term risk of adverse cardiac events who are suitable for early discharge. OBJECTIVE To compare the effectiveness of a rapid diagnostic pathway with a standard-care diagnostic pathway for the assessment of patients with possible cardiac chest pain in a usual clinical practice setting. DESIGN, SETTING, AND PARTICIPANTS A single-center, randomized parallel-group trial with blinded outcome assessments was conducted in an academic general and tertiary hospital. Participants included adults with acute chest pain consistent with acute coronary syndrome for whom the attending physician planned further observation and troponin testing. Patient recruitment occurred from October 11, 2010, to July 4, 2012, with a 30-day follow-up. INTERVENTIONS An experimental pathway using an accelerated diagnostic protocol (Thrombolysis in Myocardial Infarction score, 0; electrocardiography; and 0- and 2-hour troponin tests) or a standard-care pathway (troponin test on arrival at hospital, prolonged observation, and a second troponin test 6-12 hours after onset of pain) serving as the control. MAIN OUTCOMES AND MEASURES Discharge from the hospital within 6 hours without a major adverse cardiac event occurring within 30 days. RESULTS Fifty-two of 270 patients in the experimental group were successfully discharged within 6 hours compared with 30 of 272 patients in the control group (19.3% vs 11.0%; odds ratio, 1.92; 95% CI, 1.18-3.13; P = .008). It required 20 hours to discharge the same proportion of patients from the control group as achieved in the experimental group within 6 hours. In the experimental group, 35 additional patients (12.9%) were classified as low risk but admitted to an inpatient ward for cardiac investigation. None of the 35 patients received a diagnosis of acute coronary syndrome after inpatient evaluation. CONCLUSIONS AND RELEVANCE Using the accelerated diagnostic protocol in the experimental pathway almost doubled the proportion of patients with chest pain discharged early. Clinicians could discharge approximately 1 of 5 patients with chest pain to outpatient follow-up monitoring in less than 6 hours. This diagnostic strategy could be easily replicated in other centers because no extra resources are required.

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Chlamydia pneumoniae is an obligate intracellular bacterium implicated in a wide range of human diseases including atherosclerosis and Alzheimer's disease. Efforts to understand the relationships between C. pneumoniae detected in these diseases have been hindered by the availability of sequence data for non-respiratory strains. In this study, we sequenced the whole genomes for C. pneumoniae isolates from atherosclerosis and Alzheimer's disease, and compared these to previously published C. pneumoniae genomes. Phylogenetic analyses of these new C. pneumoniae strains indicate two sub-groups within human C. pneumoniae, and suggest that both recombination and mutation events have driven the evolution of human C. pneumoniae. Further fine-detailed analyses of these new C. pneumoniae sequences show several genetically variable loci. This suggests that similar strains of C. pneumoniae are found in the brain, lungs and cardiovascular system and that only minor genetic differences may contribute to the adaptation of particular strains in human disease.

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Introduction Hospitalisation for percutaneous coronary intervention (PCI) is often short, with limited nurse-teaching time and poor information absorption. Currently, patients are discharged home only to wait up to 4-8 weeks to commence a secondary prevention program and visit their cardiologist. This wait is an anxious time for patients and confidence or self-efficacy (SE) to self-manage may be low. Objectives To determine the effects of a nurse-led, educational intervention on participant SE and anxiety in the early post-discharge period. Methods A pilot study was undertaken as a randomised controlled clinical trial. Thirty-three participants were recruited, with n=13 randomised to the intervention group. A face-to-face, nurse-led, educational intervention was undertaken within the first 5-7 days post-discharge. Intervention group participants received standard post-discharge education, physical assessment, with a strong focus on the emotional impact of cardiovascular events and PCI. Early reiteration of post-discharge education was offered, along with health professional support with the aim to increase patients’ SE and to effectively manage their post-discharge health and well being, as well as anxieties. Self-efficacy to return to normal activities was measured to gauge participants’ abilities to manage post-PCI after attending the intervention using the cardiac self-efficacy (CSE) scale. State and trait anxiety was also measured using the State-Trait Anxiety Inventory (STAI) to determine if an increase in SE would influence participant anxiety. Results There were some increases in mean CSE scores in the intervention group participants over time. Areas of increase included return to normal social activities and confidence to change diet. Although reductions were observed in mean state and trait anxiety scores in both groups, an overall larger reduction in intervention group participants was observed over time. Conclusion It is essential that patients are given the education, support, and skills to self-manage in the early post-discharge period so that they have greater SE and are less anxious. This study provides some initial evidence that nurse-led support and education during this period, particularly the first week following PCI, is beneficial and could be trialled using alternate modes of communication to support remote and rural PCI patients and extend to other cardiovascular patients.

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Percutaneous coronary interventions have increased 50% in Australia, yet vascular and cardiac complications remain ongoing outcome issues for patients. Managing complications is confounded by reduced length of patient stay, yet is an integral component of a cardiac nurses’ scope of practice. The aim of this study was to highlight in and out of hospital vascular and cardiac complications, for twelve months post patient discharge after PCI. Prospective data was collected from the hospital angioplasty database from 1089 consecutive patients who had PCI procedures from 1 January 2005 to 31 December 2006. In hospital vascular complications were reported by 391 (35%) of the 1089 patients, following PCI. Of these, 22.4% had haemorrhage only, 7.1% haematoma only. Cardiac complications in hospital were, one death (0.09%) following PCI, three deaths (0.27%) during the same admission and no incidence of myocardial infarction or bypass surgery. Patients who had PCI in 2005 (525) were telephone followed up after discharge at one and twelve months. Surprisingly, ongoing vascular outcomes were noted, with a 2.5% incidence at one month and 4% at 12 months. Cardiac complications were also identified, 51 (9.7%) patients requiring readmission for repeat angiogram, 19 (3.6%) a repeat PCI and 7 (1.3%) patients undergoing bypass surgery. This review highlights that vascular and cardiac problems are ongoing issues for PCI patients both in and out of hospital. The results suggest that cardiac nurses focus more on improving the monitoring and discharge care of patients and families for recovery after PCI.

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Research Review on: Mueller X, Tinguely F, Tevaearai H, Revelly J, Chiolero R & Von Segess L. Pain location, distribution and intensity after cardiac surgery. Chest 2000; 118(2):391.396.

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Previous studies have shown that the external growth records of the posterior adductor muscle scar (PAMS) of the bivalve Pinna nobilis are incomplete and do not produce accurate age estimations. We have developed a new methodology to study age and growth using the inner record of the PAMS, which avoids the necessity of costly in situ shell measurements or isotopic studies. Using the inner record we identified the positions of PAMS previously obscured by nacre and estimated the number of missing records in adult specimens with strong abrasion of the calcite layer in the anterior portion of the shell. The study of the PAMS and inner record of two shells that were 6 years old when collected showed that only 2 and 3 PAMS were observed, while 6 inner records could be counted, thus confirming our working methodology. Growth parameters of a P. nobilis population located in Moraira, Spain (western Mediterranean) were estimated with the new methodology and compared to those obtained using PAMS data and in situ measurements. For the comparisons, we applied different models considering the data alternatively as length-at-age (LA) and tag-recapture (TR). Among every method we tested to fit the Von Bertalanffy growth model, we observed that LA data from inner record fitted to the model using non-linear mixed effects and the estimation of missing records using the calcite width was the most appropriate. The equation obtained with this method, L = 573*(1 - e(-0.16(t-0.02))), is very similar to that calculated previously from in situ measurements for the same population.

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Adenine nucleotides and their related compounds were determined in muscle extracts from two species of fish that were stored in ice after thawing. The fish were the closely related species, Australian barramundi (Lates calcarifer ) and Kenyan Nile perch (Lates niloticus ) which had different process histories. For all samples, adenine nucleotides did not exceed 6% of the total nucleotide pool. Inosine monophosphate (IMP) decreased steadily with storage. Hypoxanthine (Hx) was the major product of adenosine triphosphate (ATP) degradation in both barramundi and Nile perch, showing a steady increase with days of iced storage. The Hx level did not reach a maximum during the 9d storage period. The K-value also increased regularly with time of storage and for the later stages (i.e., 7 and 9d) and was significantly different (P < 0.01) for the two species. The iced storage life of these typical samples of barramundi and Nile perch was estimated to be 3d after thawing using a K-value of < 30% to indicate excellent quality. Despite the differences in process history the nucleotide profiles were remarkably similar during storage. This precludes the use of nucleotide levels as a means of differentiating between these species.

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Between-subject and within-subject variability is ubiquitous in biology and physiology and understanding and dealing with this is one of the biggest challenges in medicine. At the same time it is difficult to investigate this variability by experiments alone. A recent modelling and simulation approach, known as population of models (POM), allows this exploration to take place by building a mathematical model consisting of multiple parameter sets calibrated against experimental data. However, finding such sets within a high-dimensional parameter space of complex electrophysiological models is computationally challenging. By placing the POM approach within a statistical framework, we develop a novel and efficient algorithm based on sequential Monte Carlo (SMC). We compare the SMC approach with Latin hypercube sampling (LHS), a method commonly adopted in the literature for obtaining the POM, in terms of efficiency and output variability in the presence of a drug block through an in-depth investigation via the Beeler-Reuter cardiac electrophysiological model. We show improved efficiency via SMC and that it produces similar responses to LHS when making out-of-sample predictions in the presence of a simulated drug block.