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PubMedDate not supplied

Partitioning of respiration between the gills and air-breathing organ in response to aquatic hypoxia and exercise in the pacific tarpon, Megalops cyprinoides.

The evolution of air-breathing organs (ABOs) is associated not only with hypoxic environments but also with activity. This investigation examines the effects of hypoxia and exercise on the partitioning of aquatic and aerial oxygen uptake in the Pacific tarpon. The two-species cosmopolitan genus Megalops is unique among teleosts in using swim bladder ABOs in the pelagic marine environment. Small fish (58-620 g) were swum at two sustainable speeds in a circulating flume respirometer in which dissolved oxygen was controlled. For fish swimming at 0.11 m s(-1) in normoxia (Po2 = 21 kPa), there was practically no air breathing, and gill oxygen uptake was 1.53 mL kg(-0.67) min(-1). Air breathing occurred at 0.5 breaths min(-1) in hypoxia (8 kPa) at this speed, when the gills and ABOs accounted for 0.71 and 0.57 mL kg(-0.67) min(-1), respectively. At 0.22 m s(-1) in normoxia, breathing occurred at 0.1 breaths min(-1), and gill and ABO oxygen uptake were 2.08 and 0.08 mL kg(-0.67) min(-1), respectively. In hypoxia and 0.22 m s(-1), breathing increased to 0.6 breaths min(-1), and gill and ABO oxygen uptake were 1.39 and 1.28 mL kg(-0.67) min(-1), respectively. Aquatic hypoxia was therefore the primary stimulus for air breathing under the limited conditions of this study, but exercise augmented oxygen uptake by the ABOs, particularly in hypoxic water.

Air Sacs↗
PubMed2001

Techniques for precision irradiation of the lateral half of the rat cervical spinal cord using 150 MeV protons [corrected].

Techniques for high precision irradiation experiments with protons, to investigate the volume dependence of the tolerance dose of the rat cervical spinal cord are described. In the present study, 50% of the lateral cross section of the spinal cord was irradiated. The diameter of the cross section of this part of the rat spinal cord is at maximum 3.5 mm. Therefore, a dedicated procedure was developed to comply with the needs for a very high positioning accuracy and high spatial resolution dosimetry. By using 150 MeV protons a steep dose gradient (20-80% = 1 mm) in the centre of the spinal cord was achieved. This yields a good dose contrast between the left and right halves of the cord. A home-made digital x-ray imager with a pixel resolution of 0.18 mm/pixel was used for position verification of the spinal cord. A positioning accuracy of 0.09 mm was obtained by using information of multiple pixels. The average position stability during the irradiation was found to be 0.08 mm (1 SD) without significant systematic deviations. Profiles of the dose distribution were measured with a 2D dosimetry system consisting of a scintillating screen and a CCD camera. Dose volume histograms of the whole spinal cord as well as separately of the white and grey matters were calculated using MRI imaging of the cross section of the rat cervical spinal cord. From the irradiation of 20 animals a dose-response curve has been established. MRI showed radiation-induced damage at the high dose side of the spinal cord. Analysis of the preliminary dose-response data shows a significant dose-volume effect. With the described procedure and equipment it is possible to perform high precision irradiations on selected parts of the spinal cord.

Animals↗
PubMed2005

The significance of skeletal-related events for the health-related quality of life of patients with metastatic prostate cancer.

BACKGROUND: We examined the clinical relevance of skeletal-related events (SREs) for health state preferences, pain and health-related quality of life in patients with advanced prostate cancer and a history of bone metastases. PATIENTS AND METHODS: Data were from a clinical trial of zoledronic acid versus placebo in the treatment of SREs associated with advanced prostate cancer metastatic to bone. Patients (n=248) were included if they experienced an SRE during the study. Outcome measures were assessed at fixed intervals. We used mixed-effects models to estimate changes in outcomes after each patient's first SRE. RESULTS: There were clinically meaningful and statistically significant declines in physical well-being after: radiation and pathologic fractures; functional well-being after radiation; and emotional well-being after radiation and pathologic fractures. There also were meaningful and significant declines in preference and utility scores after radiation and fracture. Pain intensity declined after radiation, but not after other SREs; no other pain measure changed substantively. CONCLUSIONS: SREs have important and significant effects on measures of health-related quality of life in men with prostate cancer. Treatments that prevent SREs may not demonstrate corresponding effects on outcomes if the effects of SREs occur between scheduled outcome assessments. Implications for trial design are discussed.

Aged↗
PubMed1995

Maternal dietary carbohydrate restriction and mild-to-moderate exercise during pregnancy modify aspects of fetal development in rats.

To determine whether acute bouts of exercise during pregnancy would predispose the fetus to increased risk if maternal dietary carbohydrate were restricted, untrained pregnant rats were randomly assigned to a 0% (low), 12% (moderate) or 60% (high) glucose diet, and either rested or exercised daily for 20 min from d 16 to term on a rodent treadmill at a mild (15.5 m/min) or moderate (24.3 m/min) intensity. A 3 x 3 nested factorial model with and without food intake as a covariate was employed. Both greater exercise intensity and the lower levels of dietary carbohydrate independently decreased term maternal liver and plantaris glycogen concentrations and increased plasma lactate concentrations. However, significant differences due to exercise disappeared (except for plasma lactate) with food intake controlled for in the model, indicating that energy deficits modulated these exercise effects. In contrast, for the offspring, when food intake was controlled for, a restricted level of maternal dietary carbohydrate significantly lowered fetal weight, plasma glucose and insulin concentrations and liver glycogen concentrations measured at term. Exercise alone did not reduce mean fetal weight if nested weights within a litter were used in the statistical analysis. Mild to moderate maternal exercise lowered only fetal plasma glucose concentrations and only if maternal food intake was not controlled for. These results indicate that acute exercise during pregnancy can have detrimental effects on fetal development only if dietary glucose is severely restricted. Otherwise, adequate glucose and energy in the maternal diet in untrained pregnant rats during repeated bouts of acute exercise seem to protect the fetus.

Amniotic Fluid↗
PubMed1987

Perceptions of physical therapy competencies in rheumatology. Physical therapists versus rheumatologists.

The purpose of this article is to report the differences in perceptions among three groups of respondents who assessed the importance of 80 competencies for entry-level physical therapists who treat patients with arthritis. Nonparametric statistics were used to analyze the responses of physical therapists and rheumatologists who completed a questionnaire regarding the competencies. I used the Kruskal-Wallis one-way analysis of variance to make group comparisons and the Mann-Whitney U test to complete pair-wise comparisons. The results revealed significant differences of opinion among the groups (p = .007) for 20 of the 80 competencies. The significant differences in opinion were among physical therapy clinical educators (n = 100), physical therapy arthritis health professionals (n = 108), and rheumatologists (n = 80). Although the results suggested that some groups perceived certain physical therapy competencies in rheumatology to be useful but not essential for the entry-level physical therapist to perform, considerable variability existed within groups. Despite the variance in opinions, teaching of these competencies should be included in the entry-level physical therapy curriculum or in clinical settings.

Arthritis↗
PubMed1995

Significant digits: foundations, myths and utilization.

Scientific text books, journal articles, and all types of other sources of scientific information frequently give certain recommendations and/or make statements of presumed fact concerning the issue of significant digits in scientific computation. Most of these "well-known" facts concerning significance in computation are false. This article discusses the folklore of significant digits, debunks the common cliches, illustrates the actual behavior of computational significance in a typical scenario, and makes recommendations concerning these matters.

Biometry↗
PubMed2000

Verification and modification of the ICRP-67 model for plutonium dose calculation.

On the basis of the available data and empirical expressions for the plutonium excretion after injection, an age-related compartmental model has been developed. It provides a better agreement with measured urinary excretion data than the current ICRP 67 model. Moreover, the revised model avoids unphysiological assumptions such as the transfer of activity from soft tissue to urinary bladder, that were part of the ICRP model. The new predictions of the activity in feces and in blood after an injection are closer to the available data than the ICRP 67 estimations and there is also a good agreement with the partitioning of plutonium between skeleton and liver obtained from different autopsy studies. Furthermore, the urinary excretion estimated by the improved model has been checked using some data from occupationally exposed individuals. As the plutonium uptake in these workers occurred by inhalation, the improved model and the ICRP 67 model were compared by connecting them to the ICRP 66 respiratory tract model. The improved model consistently yields a better agreement with the measured excretion and higher estimations of intake than the ICRP 67 model.

Body Burden↗
PubMed1985

Assessment of tardive dyskinesia using the Abnormal Involuntary Movement Scale.

Over a 10-month period, 33 patients with tardive dyskinesia (TD) were evaluated with the Abnormal Involuntary Movement Scale (AIMS) simultaneously and independently by two experienced and two inexperienced raters. The experienced raters generally had higher levels of agreement and their scores were more consistent over time. It is concluded that experience with TD influences AIMS inter-rater reliability and that it is useful to differentiate TD movements into the dimensions of quality, frequency, and amplitude, dimensions not currently used in the AIMS. The usefulness and difficulty of developing more specific guidelines for AIMS ratings are discussed.

Ambulatory Care↗
PubMed1997

Swimmers' compliance with training prescription.

The purpose of this study was to determine how closely competitive swimmers complied with their coaches' prescriptions when training in squads. A training session early in the buildup phase of the season was observed for each of 24 coaches who had been randomized to two groups: an experimental, high-intensity, low-distance program (E) and a control (usual) program (C). Swim distances, rest durations, and swim durations for at least one set of prescribed repetitions (reps) were recorded for each of 47 swimmers (87 sets, 429 reps) in E and for 49 swimmers (79 sets, 402 reps) in C. The pace of each rep, expressed as percent of the swimmer's current personal best pace for the distance of the rep, represented observed intensity. There was almost perfect agreement between the prescribed and observed swim distances for the set of reps (Spearman r = 0.99 in both groups). Prescribed and observed rest intervals were also closely matched in E and C (Spearman r = 0.87 and 0.77 respectively). Four coaches in E and 10 coaches in C prescribed intensity subjectively as easy, moderate, hard, or race-pace; mean +/- SD observed intensities (%) for their swimmers were 79 +/- 6, 81 +/- 3, 91 +/- 2, and 93 +/- 5, respectively. The relationship between these coaches' subjective training prescription and individual swimmers' interpretations of these intensities was poor (Cohen's kappa = 0.39). Nine coaches in E prescribed intensity as percent of personal best pace. Although the mean prescribed and observed intensities for their swimmers were similar (89 +/- 4 and 90 +/- 7, respectively), the relationship between individual values was poor (Pearson r = 0.30). We conclude that swimmers complied with prescribed distances and rest intervals but were less effective in judging the intensity of swim training. We recommend that coaches monitor training intensity more closely.

Humans↗
PubMed1998

Creatine supplementation in endurance sports.

PURPOSE: Creatine is a physiologically active substance indispensable to muscle contraction. The increase in creatine phosphate obtained by supplementation is greater than the increase in total creatine achieved by specific sports training. Less well-trained people can produce an immediate energy store when supplementing creatine such as is otherwise achieved by top athletes on normal nutrition by means of speed and power training. The publications so far available indicate that creatine accumulation in muscle was accomplished using relatively high doses (20 g daily over 5 d). The objective of our study was to investigate the alterations in creatine and creatinine concentrations following lower dosages. METHODS: As intermediate and finishing spurts under anaerobic conditions are gaining in importance in endurance sports, we created a special exercise test for triathletes combining endurance and interval performance. After a pretreatment exercise test was performed, the athletes ingested 6 g of creatine daily, divided into two portions for 5 d. On day 6, another exercise test was performed. RESULTS: Creatine supplementation was found to have no influence on the cardiovascular system, oxygen uptake, and blood lactate concentration. The fall in blood glucose during the exercise test was significantly reduced after consumption of creatine. Although interval power performance was significantly increased by 18%, endurance performance was not influenced. CONCLUSIONS: We conclude that creatine supplementation at doses of 6 g daily has positive effects on short-term exercise included into aerobic endurance exercise.

Administration, Oral↗
PubMed1999

Is determination of exercise intensities as percentages of VO2max or HRmax adequate?

UNLABELLED: Often exercise intensities are defined as percentages of maximal oxygen uptake (VO2max) or heart rate (HRmax). PURPOSE: The purpose of this investigation was to test the applicability of these criteria in comparison with the individual anaerobic threshold. METHODS: One progressive cycling test to exhaustion (initial stage 100 W, increment 50 W every 3 min) was analyzed in a group of 36 male cyclists and triathletes (24.9 +/- 5.5 yr; 71.6 +/- 5.7 kg; VO2max: 62.2 +/- 5.0 mL x min(-1) x kg(-1); individual anaerobic threshold = IAT: 3.64 +/- 0.41 W x kg(-1); HRmax: 188 +/- 8 min). Power output and lactate concentrations for 60 and 75% of VO2max as well as for 70 and 85% of HRmax were related to the IAT. RESULTS: There was no significant difference between the mean value of IAT (261 +/- 34 W, 2.92 +/- 0.65 mmol x L(-1)), 75% of VO2max (257 +/- 24 W, 2.84 +/-0.92 mmol x L(-1)), and 85% of HRmax (259 +/- 30 W, 2.98 +/- 0.87 mmol L(-1)). However, the percentages of the IAT ranged between 86 and 118% for 75% VO2max and 87 and 116% for 85% HRmax (corresponding lactate concentrations: 1.41-4.57 mmol x L(-1) and 1.25-4.93 mmol x L(-1), respectively). The mean values at 60% of VO2max (198 +/- 19 W, 1.55 +/- 0.67 mmol x L(-1)) and 70% of HRmax (180 +/- 27 W, 1.45 +/- 0.57 mmol x L(-1)) differed significantly (P < 0.0001) from the IAT and represented a wide range of intensities (66-91% and 53-85% of the IAT, 0.70-3.16 and 0.70-2.91 mmol x L(-1), respectively). CONCLUSIONS: In a moderately to highly endurance-trained group, the percentages of VO2max and HRmax vary considerably in relation to the IAT. As most physiological responses to exercise are intensity dependent, reliance on these parameters alone without considering the IAT is not sufficient.

Adult↗
PubMed2001

Do 9- to 12 yr-old children meet existing physical activity recommendations for health?

PURPOSE: The purpose of this study was to investigate whether a sample of 9- to 12-yr-old children fulfilled existing U.S. and UK physical activity recommendations for health. METHODS: Habitual physical activity levels of 79 pre- and early pubertal children were assessed using continuous heart rate monitoring over a period of 4 d. Mean, daily, cumulative physical activity levels spent above heart rate thresholds were compared with U.S. and UK recommended values. RESULTS: In this study, when cumulative amounts of physical activity were considered, at intensities greater than 120 beats x min(-1) and 75% above resting heart rate, pre- and early pubertal British children appear to engage in sufficient physical activity to meet U.S. and UK minimum daily recommendations. CONCLUSIONS: Interpretations of children's physical activity levels depend on thresholds set for intensity of physical activity and whether cumulative or continuous bouts of activity are included in the analysis.

Anthropometry↗
PubMed2005

Hyperbaric oxygen for the treatment of fournier's gangrene.

PURPOSE: Fournier's gangrene is a necrotizing fasciitis of the genitalia that is associated with high morbidity and mortality. Groups at many institutions have initiated routine adjuvant hyperbaric oxygen (HBO) therapy. We examined whether HBO has made a difference in the morbidity, mortality and costs associated with treating this disease. We also analyzed predictors of extended hospital stay and mortality. MATERIALS AND METHODS: The records of patients with the hospital discharge diagnoses of Fournier's gangrene, necrotizing fasciitis, gangrene of the genitalia and scrotal gangrene from 1993 to 2002 were reviewed. Data concerning clinical presentation characteristics, hospital stay, complications, hospital charges and outcomes, including graft failure and death, were analyzed. RESULTS: A total of 42 patients were identified and followed a median 4.2 years. Of the patients 16 underwent surgical debridement and antibiotic therapy alone, and 26 were treated with HBO plus surgery and antibiotics. Overall disease specific mortality was 21.4%, that is 12.5% in the nonHBO group and 26.9% in the HBO group. Three or more complications occurred in 13% of nonHBO and in 19% of HBO cases, of which the most common was myocardial infarction. The skin graft failure rate was 6% (nonHBO) and 8% (HBO). Physical disability was a statistically significant predictor of extended hospital stay (p <0.01). There was a trend toward a correlation between known coronary artery disease and death (p = 0.2). A statistically significant difference was noted in average daily hospital charges in nonHBO vs HBO cases ($2,552 vs $3,384 daily, p <0.01). CONCLUSIONS: These data do not support routine HBO in the treatment of Fournier's gangrene. There was a trend toward higher morbidity and mortality in the HBO group, suggesting that treatment may have been given to patients who were more ill.

Adult↗
PubMed2004

Resonant Raman spectroscopy of nanotubes.

Single and double resonances in Raman scattering are introduced and six criteria for the observation and identification of double resonances stated. The experimental situation in carbon nanotubes is reviewed in view of these criteria. The evidence for the D mode and the high-energy mode is found to be overwhelming for a double-resonance process to take place, whereas the nature of the radial breathing-mode Raman process remains undecided at this point. Consequences for the application of Raman scattering to the characterization of nanotubes are discussed.

Carbon↗