Creatine supplementation does not impair the thermoregulatory response during a bout of exercise in the heat.

AIM: The aim of this work was to examine the effects of creatine (Cr) supplementation on resting body water volumes and on core temperature and sweat loss during a bout of exercise in a warm environment. METHODS: Twenty-four aerobically trained male subjects (age 22.93+/-3.01 years, height 179.52+/-7.28 cm, mass 82.06+/-14.32 kg) volunteered to participate in this study. Each subject was assessed for resting body water volumes and for body mass (BM), heart rate (HR), blood pressure (BP), and core temperature immediately before and following a 60-min bout of exercise in a warm environment. Core temperature, HR, and BP were also recorded at 10-min intervals during exercise. Subjects were then randomly assigned to either a Cr or placebo (P) group. Each subject returned following a 5-day supplementation period and was reassessed using identical testing procedures. BM was measured using a standard electronic scale. Body water volumes were assessed using a multi-frequency BIS (Xitron Technologies, San Diego, CA, USA). Core body temperature was measured using a CorTemp Disposable Temperature Sensor and a CT2000 Miniaturized Ambulatory Recorder (HTI Technologies, Inc., Palmetto, FL, USA). RESULTS: The Cr group experienced a significant increase in all body water volumes. No changes were observed in the P group. No changes in core temperature or sweat loss were observed in either group following supplementation. CONCLUSIONS: Cr loading did not impair the thermoregulatory response during a bout of exercise in the heat.

Public health risks of railroad hazardous substance emergency events.

The number of railroad events reported to the Agency for Toxic Substances and Disease Registry's Hazardous Substances Emergency Events Surveillance system increased from 84 in 1993 to 177 in 1998. Comparisons of data on railroad and non-railroad events were made. The results overall indicated a greater potential impact of railroad events on public health. A median number of 2039 persons were living within a 1-mile radius of railroad events versus 982 for non-railroad events. The percentage of events during times when people are more likely to be home was also greater for railroad events. Railroad event victims were more likely to need hospital treatment than non-railroad event victims, which suggested the need for better community planning, reevaluation of current federal regulations and priorities for railroad hazardous material transport, and enhanced railroad industry commitment to safety.

Ephedra and its application to sport performance: another concern for the athletic trainer?

OBJECTIVE: The ma huang herb, otherwise known as ephedra, has gained widespread popularity as an ergogenic supplement. With the sympathomimetic alkaloid ephedrine as its primary active ingredient, ma huang is marketed to reduce fatigue; increase strength, power, and speed; decrease reaction time; and improve body composition. Although numerous side effects have been associated with the use of ma huang, its popularity in athletes continues to grow. This review provides rationale for the ergogenic claims regarding ma huang and compares and contrasts those claims with data from scientifically controlled investigations. DATA SOURCES: MEDLINE and SPORT Discus were searched from 1970 to 2000 using the key words ma huang, ephedra, and ephedrine in combination with humans, exercise, performance, and side effects. DATA SYNTHESIS: Ephedrine has been used alone or in combination with other drugs as an effective weight-loss agent. The weight loss has been attributed to thermogenic and lipolytic effects which, in combination with the central nervous system stimulating effects, have also resulted in its use as an ergogenic aid. Most of the scientific data, however, do not support manufacturers' ergogenic claims, and numerous side effects have been associated with ephedrine use. Thus, the safety and efficacy of ma huang as an ergogenic supplement must be questioned. CONCLUSIONS/RECOMMENDATIONS: It appears that the risks associated with the use of ma huang far outweigh any possible ergogenic benefits. Thus, it is extremely important that athletic trainers educate athletes on these issues so they can continue to perform at an optimum level in a safe and healthy manner.

Effect of strength and proprioception training on eversion to inversion strength ratios in subjects with unilateral functional ankle instability.

OBJECTIVES: To examine the effect of six weeks of strength and proprioception training on eversion to inversion isokinetic strength ratios (E/I ratios) in subjects with unilateral functional ankle instability. METHODS: Thirty eight subjects were randomly assigned to one of four treatment groups: strength training (S); proprioception training (P); strength + proprioception training (B); control (C). Isokinetic strength was tested before and after training using a Kin Com 125 automatic positioning isokinetic dynamometer. Subtalar joint eversion and inversion motions were tested both concentrically and eccentrically through a range of motion involving 40 degrees. All peak torque and average torque values were normalised for body mass. E/I ratios were calculated from average torque and peak torque measures by taking the concentric eversion value and combining it with the eccentric inversion value. Data were analysed using a mixed model analysis of variance with repeated measures on the test factor. Average torque and peak torque E/I ratios at 30 and 120 degrees/s were analysed separately. RESULTS: There were no significant differences in average torque and peak torque E/I ratios of the functionally unstable ankle for any of the groups after training compared with before. CONCLUSIONS: Six weeks of strength and proprioception training (either alone or combined) had no effect on isokinetic measures of strength in subjects with self reported unilateral functional instability. Further studies examining this agonist (concentric) to antagonist (eccentric) muscle group strength ratio are needed.

Tyrosine, phenylalanine, and disulfide contributions to the circular dichroism of proteins: circular dichroism spectra of wild-type and mutant bovine pancreatic trypsin inhibitor.

Improved descriptions of the lowest energy excited states of tyrosine and phenylalanine side chains have been developed in order to extend the capabilities of calculating the circular dichroism (CD) spectra of proteins. Four transitions (Lb, La, Bb, and Ba) for each of the side-chain chromophores were considered, and the transition monopole charges were obtained from a CNDO/S calculation on models representing the individual groups. Monopole charges at midpoints of the bonds, corresponding to the maximum transition charge densities in the Lb band, and monopole charges representing the vibronic coupling with the B transitions for the La transition were also included. The aromatic transitions were combined with the peptide transitions (npi, pi0pi n'pi, and pi+pi) and disulfide transitions (n1sigma and n4sigma) in the framework of the origin-independent matrix method to compute the CD spectra of different crystal forms and Y --> L and F --> L mutants of bovine pancreatic trypsin inhibitor (BPTI). The structures of the mutants were obtained by replacing the appropriate tyrosine or phenylalanine residue by leucine in the wild-type crystal structure. The CD calculations were performed on the energy-minimized structures. The CD spectrum calculated for the form II crystal structure of BPTI showed the best agreement with experiment. In the far UV, the calculated and experimental CD spectra agree to various extents for the wild-type and mutant BPTI. Among the mutants, the calculated CD spectra of Y4L, Y10L, Y23L, and F45L showed reasonable agreement with experiment, while those of Y21L and F22L, the two residues interacting with most aromatic groups, showed poor agreement. In the near UV, the negative bands predicted for the wild-type and mutant BPTI have much less intensity than observed experimentally.

Thermal stability of low molecular weight urokinase during heat treatment. II. Effect of polymeric additives.

Turbidimetric or light scattering assays can be used to determine the extent of aggregation in protein formulations. Using low molecular weight urokinase (LMW-UK) as a model protein, the effect of polymeric additives on heat-induced aggregation was evaluated. Previous work has shown that under 60 degrees C heat treatment, LMW-UK initially denatures and the unfolded protein associates to form soluble aggregates. Eventually, these aggregates associate to form a precipitate. The effects of polymers on the initial aggregation phase was examined. Hydroxyethyl (heta) starch, polyethylene glycol 4000, and gelatin were found to be effective, concentration-dependent inhibitors of aggregation, whereas polyvinylpyrrolidone (PVP) and polyethylene glycol 300 were ineffective. Overall, the effect of polymeric additives on the stability of thermally-stressed LMW-UK can be accounted for by preferential exclusion of the solute from the surface of the protein.