Exercise for acutely hospitalised older medical patients.

BACKGROUND: A high incidence of functional decline (deterioration in physical or cognitive function) during hospitalisation of older adults is reported. The role of exercise in preventing these deconditioning effects is unclear. OBJECTIVES: To determine the effect of exercise interventions for acutely hospitalised older medical patients on functional status, adverse events and hospital outcomes. SEARCH STRATEGY: We searched MEDLINE (1966-Feb 2006), CINAHL (1982-Feb 2006), EMBASE (1988 to Feb 2006), Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2006), PEDro (1929- Feb 2006), Current Contents (1993- Feb 2006) and Sports Discus (1830-Feb 2006). The Journal of the American Geriatrics Society was hand searched. Additional studies were identified through reference and citation tracking, personal communications with a content expert and contacting authors of eligible trials. There was no language restriction. SELECTION CRITERIA: Eligible studies were prospective randomised controlled trials (RCT) or prospective controlled clinical trials (CCT) comparing exercise for acutely hospitalised older medical patients to usual care or no treatment controls. DATA COLLECTION AND ANALYSIS: Two independent reviewers extracted data relating to patient and hospital outcomes and assessed the method quality of included studies. Data were pooled in meta-analysis using the relative risk (RR) and absolute risk reduction (ARR) for dichotomous outcomes and the standardised mean difference (SMD) or the weighted mean difference (WMD) for continuous outcomes. MAIN RESULTS: Of 3138 potentially relevant articles screened, 7 randomised controlled trials and 2 controlled clinical trials were included. The effect of exercise on functional outcome measures is unclear. No intervention effect was found on adverse events. Pooled analysis of multidisciplinary interventions that included exercise indicated a small significant increase in the proportion of patients discharged to home at hospital discharge (Relative Risk 1.08, 95% CI 1.03 to 1.14 and Numbers Needed to Treat 16, 95% CI 11 to 43) and a small but important reduction in acute hospital length of stay (weighted mean difference, -1.08 days, 95% CI -1.93 to -0.22) and total hospital costs (weighted mean difference, -US$278.65, 95% CI -491.85 to -65.44) compared to usual care. Pooled analysis of exercise intervention trials found no effect on the proportion of patients discharged to home or acute hospital length of stay. AUTHORS' CONCLUSIONS: There is 'silver' level evidence (www.cochranemsk.org) that multidisciplinary intervention that includes exercise may increase the proportion of patients discharged to home and reduce length and cost of hospital stay for acutely hospitalised older medical patients.

Encouraging healthy spine habits to prevent low back pain in children: an observational study of adherence to exercise.

BACKGROUND: Low back pain (LBP) in adolescence is a predictor of adult LBP. Strategies to educate children and encourage healthy spine habits may prevent LBP. Poor adherence to health programmes can be a barrier to their success. This study addresses the potential for habitualisation of a short daily exercise programme that draws attention to factors thought to keep the spine healthy. OBJECTIVES: To describe adherence to a 9-month exercise programme, and analyse factors that may influence adherence. DESIGN: Observational cohort study. SETTING: Four primary schools in New Zealand. OUTCOME MEASURES: Outcomes included self-evaluation of adherence to exercise, and self-reported incidence and severity of LBP. PARTICIPANTS: Children (n=469) aged 8 to 11 years. METHODS: Participants were taught four simple spine movements for daily practice as part of a health programme that emphasised 'back awareness' and self-care of the spine. Strategies to encourage adherence were implemented. Data on self-reported adherence and episodes of LBP during the previous week were collected through an online survey completed on trial days 7, 21, 49, 105, 161 and 270 over a 9-month period. RESULTS: Daily exercise adherence was 34% on day 7 and dropped to 9% by day 270. Exercise adherence of at least once per week was 84% on day 7 and 47% by day 270. Frequency of exercise was not associated with episodes of LBP [odds ratio (OR) 1.16, 95% confidence interval (CI) 0.92 to 1.47, P=0.21], previous history of LBP (OR 0.97, 95% CI 0.77 to 1.23, P=0.77), lifetime first episode of LBP (defined as the first episode of LBP in the study period for participants with no previous history of LBP) (OR 0.39, 95% CI 0.15 to 1.34, P=0.14) or severity of LBP (OR 1.59, 95% CI 0.99 to 2.52, P=0.05). CONCLUSION: This study applied a comprehensive set of strategies considered to be important in encouraging adherence, but was not successful in sustaining the interest of more than half of the cohort. Innovative strategies are needed to develop new exercise habits in children. CLINICAL TRIAL REGISTRATION NUMBER: ACTRN12611000551998.

The influence of subject and test design on dynamometric measurements of extremity muscles.

In the context of broader discussions of clinical dynamometry, earlier reviews have raised concerns about the potential effects of variations in subject factors and test procedures on measurements. None, however, have dealt exclusively with these effects. We therefore reviewed more than 200 articles to evaluate in detail the effects of variations in subject factors and test procedures on measurements. Factors relating to subjects that affected measurements were age, gender, weight, athletic background, disability, and limb dominance. Test conditions that led to variations in measurements were range of movement in which values were obtained, type of contraction or movement (concentric, eccentric, isokinetic, isometric, isotonic), pretest procedures (warm-up and gravity-correction procedures, starting position, stabilization, axes alignment, lever arm length, preload, damp/ramp settings), test conditions (speed, test sequence, rest intervals, feedback), and type of data analysis (the data selected and how they are manipulated). In the majority of the publications, the authors failed to provide sufficient detail for accurate replication of test procedures or for comparison with other studies. We advocate that the factors identified in this review be included whenever measurements obtained with a dynamometer are reported. Effective development of normative data, formation of ratios, comparison of measurements across studies, and relating measurements with other performance criteria (eg, measurements of functional performance) all require descriptions of variables relating to subjects and testing. Similarly, meaningful use of these measurements in clinical practice requires consideration and documentation of these variables.

Method-related variations in estimates of gravity correction values using electromechanical dynamometry: a knee extension study.

Dynamometry is widely used to measure subject strength. The method employed to correct dynamometry scores for gravitational influences can result in differing correction estimates. This study investigates differences between mathematical estimates of correction values and directly measured passive forces. Using the Kin-Com dynamometer, passive force measurements from 90 degrees of knee flexion to full extension were collected for nine asymptomatic subjects. These measurements were then compared with correction estimates mathematically extrapolated from a force reading obtained at one point in the test range. Direct passive measurements obtained between 0 and 70 degrees of knee flexion and mathematical estimates of correction values differed by as much as 50 N. The equivalence of gravity correction values obtained using the two methods detailed cannot be assumed. Mathematical estimates of correction values for knee scores obtained between 0 and 90 degrees of flexion were found to be clinically identical to direct passive measurements when: 1) the limb was weighed close to 50 degrees of flexion and 2) the angular location of the lower limb mass relative to the horizontal was not assumed to be represented by the angular location of the lever arm, but rather 15 degrees further below the horizontal than the lever arm.

Comparison of forehead Max-Fast pulse oximetry sensor with finger sensor at high positive end-expiratory pressure in adult patients with acute respiratory distress syndrome.

In the critical care setting it may be difficult to determine an accurate reading of oxygen saturation from digital sensors as a result of poor peripheral perfusion. Limited evidence suggests that forehead sensors may be more accurate in these patients. We prospectively compared the accuracy of a forehead reflectance sensor (Max-Fast) with a conventional digital sensor in patients with acute respiratory distress syndrome during a high positive end-expiratory pressure (PEEP) recruitment manoeuvre (stepwise recruitment manoeuvre). Sixteen patients with early acute respiratory distress syndrome were enrolled to evaluate the blood oxygen saturation during a stepwise recruitment manoeuvre. PEEP was increased from baseline (range 10 to 18) to 40 cmH2O, then decreased to an optimal level determined by individual titration. Forehead and digital oxygen saturation and arterial blood gases were measured simultaneously before, during and after the stepwise recruitment manoeuvre at five time points. Seventy-three samples were included for analysis from 16 patients. The SaO2 values ranged from 73 to 99.6%. The forehead sensor provided measurements that deviated more from arterial measures than the finger sensor (mean absolute deviations 3.4%, 1.1% respectively, P=0.02). The greater variability in forehead measures taken at maximum PEEP was reflected in the unusually large precision estimates of 4.24% associated with these measures. No absolute differences from arterial measures taken at any other time points were significantly different. The finger sensor is as accurate as the forehead sensor in detecting changes in arterial oxygen saturation in adults with acute respiratory distress syndrome and it may be better at levels of high PEEP such as during recruitment manoeuvres.

The purification of ribosomal RNA gene chromatin from Physarum polycephalum.

We have undertaken the purification of ribosomal RNA gene (rDNA) chromatin from the slime mold Physarum polycephalum, in order to study its chromatin structure. In this organism rDNA exists in nucleoli as highly repeated minichromosomes, and one can obtain crude chromatin fractions highly enriched in rDNA from isolated nucleoli. We first developed a nucleolar isolation method utilizing polyamines as stabilization agents that results in a chromatin fraction containing far more protein than is obtained by the more commonly used divalent cation isolation methods. The latter method appears to result in extensive histone loss during chromatin isolations. Two methods were then used for purifying rDNA chromatin from nucleoli isolated by the polyamine procedure. We found that rDNA chromatin migrates as a single band in agarose gels, well separated from other components in the chromatin preparation. Although the utility of this technique is somewhat limited by low yields and by progressive stripping of protein from rDNA chromatin, it can provide useful information about rDNA chromatin protein composition. The application of this technique to the fractionation of gene and spacer chromatin fragments produced by restriction enzyme digestion is discussed. We also found that rDNA chromatin, if RNase-treated, bands discretely in metrizamide equilibrium density gradients with a density lighter than that of non-nucleolar chromatin. These characteristics suggest that we have identified a transcriptionally active rDNA chromatin fraction which possesses a lower protein to DNA ratio than does non-nucleolar chromatin. This technique yields sufficient purified rDNA chromatin for further biochemical studies and does not cause extensive protein stripping. The procedures developed here should be applicable to the analysis of a variety of chromatin fractions in other systems.

The characterization of ribosomal RNA gene chromatin from Physarum polycephalum.

We have isolated ribosomal RNA gene (rDNA) chromatin from Physarum polycephalum using a nucleolar isolation procedure that minimizes protein loss from chromatin and, subsequently, either agarose gel electrophoresis or metrizamide gradient centrifugation to purify this chromatin fraction (Amero, S. A., Ogle, R. C., Keating, J. L., Montoya, V. L., Murdoch, W. L., and Grainger, R. M. (1988) J. Biol. Chem. 263, 10725-10733). Metrizamide-purified rDNA chromatin obtained from nucleoli isolated according to the new procedure has a core histone/DNA ratio of 0.77:1. The major core histone classes comigrate electrophoretically with their nuclear counterparts on Triton-acid-urea/sodium dodecyl sulfate two-dimensional gels, although they may not possess the extent of secondary modification evident with the nuclear histones. This purified rDNA chromatin also possesses RNA polymerase I activity, and many other nonhistone proteins, including two very abundant proteins (26 and 38 kDa) that may be either ribonucleoproteins or nucleolar matrix proteins. Micrococcal nuclease digestion of the metrizamide-purified rDNA chromatin produces particles containing 145-base pair DNA fragments identical in length to those in total chromatin and which contain both transcribed and nontranscribed rDNA sequences. Some smaller fragments (30, 70, and 110 base pairs) are also seen, but their sequence content is not known. These particles sediment uniformly at 11 S in sucrose gradients containing 15 mM NaCl, and at 4-11 S in gradients containing 0.35 M NaCl. Particles enriched in gene or nontranscribed spacer sequences are not resolved in these sucrose gradients or in metrizamide gradients. Our findings suggest that the rDNA chromatin fraction we have identified contains transcriptionally active genes and that an organized, particle-containing structure exists in active rDNA chromatin.

Issues in setting health-based cleanup levels for arsenic in soil.

Health risk assessments often do not take into account the unique aspects of evaluating exposures to arsenic in soil. For example, risks from ingestion of arsenic in soil are often based on toxicity factors derived from studies of arsenic (soluble arsenate or arsenite) in drinking water. However, the toxicity of arsenic in drinking water cannot be directly extrapolated to toxicity of soil arsenic because of differences in chemical form, bioavailability, and excretion kinetics. Because of the differences between soil arsenic and water arsenic, we conclude that risks from arsenic in soil are lower than what would be calculated using default toxicity values for arsenic in drinking water. Site-specific risk assessments for arsenic in soil can be improved by characterizing the form of arsenic in soil, by conducting animal feeding or in vitro bioavailability studies using site soils, and by conducting studies to evaluate the relationship between urinary arsenic and soil arsenic levels. Such data could be used to more accurately measure the contribution that soil arsenic makes to total intake of arsenic. Available data suggest that arsenic usually makes a small contribution to this total.