Sports injury experiences from the Western Australian Sports Injury Cohort Study

OBJECTIVE: The Western Australian Sports Injury Study is the first prospective cohort study of sports injuries sustained during community-level sports participation in Australia. METHODS: The players were nonprofessional/non-elite participants of hockey, Australian football, basketball and netball from metropolitan Perth. Players completed a baseline questionnaire relating to their sports injury history, training practices, protective equipment use, demographic profile, general health and lifestyle factors. Sports participation and injury experiences were monitored by monthly telephone surveys over two consecutive five-month winter sporting seasons during 1997 and 1998. RESULTS: Of the 1,512 players recruited into the initial cohort, 966 (i.e. 64%) responded to at least 700% of the callback surveys over the two-year follow-up. Across all sports, the injury incidence rate was 16.1 injuries/ 1,000 exposure hours (both games and training). Injury rates were highest in Australian football and lowest in netball. Lower limb injuries were twice as common as those to the upper limb (67% vs. 31%). Three-quarters of injured players sought treatment from a health care practitioner. CONCLUSIONS AND IMPLICATIONS: This is the first longitudinal study of injuries to community-based sports participants in Australia. Compared with elite sports participants, the risk of injury is relatively low. The results provide valuable direction for the design and conduct of further aetiological studies.     

NoiseChem: An European Commission research project on the effects of exposure to noise and industrial chemicals on hearing and balance

Exposure to multiple physical and chemical agents is common in occupational environments but workplace hazards and occupational safety criteria for combined exposures is lacking. NoiseChem is an European Commission research project examining the effects of exposure to noise and chemicals on hearing and balance. Partners in Sweden, Finland, France, Denmark, UK and Poland with expert guidance from partners in USA will examine workers and study the mechanisms of action in animals to determine the levels of risk associated with joint exposure to noise and solvents. This paper briefly outlines the project details.     

Occupational exposure to insecticides and their effects on the auditory system

The objective of this investigation was to study the effects of occupational exposure to organophosphates and pyrethroid insecticides on the central auditory system. The study group consisted of 98 workers exposed to insecticides and 54 non-exposed workers. Data on work history, medical history, present diseases, occupational and non-occupational exposure to noise or chemicals and lifestyle factors were obtained through an interview. Central auditory system functions were assessed through frequency patterns and duration patterns testing. Fifty-six percent of the exposed workers had hearing dysfunction at the central level and its relative risk was 7.58 for the group with exposure to insecticides (95% CI 2.9- 19.8) when compared to the non-exposed group. The group exposed to insecticides and noise had a relative risk for central disorders of 6.5 (95% CI 2.2-20.0) when compared to the non-exposed group and 9.8 (95% CI 1.4-64.5) when compared to the group exposed only to noise. The finding suggests that exposure to organophosphates and pyrethroid products can induce damage to central auditory system. Further research is needed on the ototoxic mechanisms of these chemicals, and on hearing loss prevention measurements that are applicable and adequate to such risks and populations.     

Differential sensitivity to tetrodotoxin and lack of effect of prostaglandin E2 on the pharmacology and physiology of propagated action potentials

1. We have studied the effects of prostaglandin E(2) (PGE(2)) on action potential propagation in the isolated, desheathed vagus and saphenous nerves of rats using an extracellular grease gap recording method. 2. PGE(2) evoked a small depolarization of vagus nerves but had no effect on the stimulation threshold, size or latency of either the A wave (corresponding to conduction in A fibres) or the C wave (corresponding to conduction in C fibres) of the compound action potential (CAP) recorded from either vagus or saphenous nerves. 3. Lidocaine (0.01 - 10 mM) reduced all components of the CAP of both vagus and saphenous nerves. PGE(2) had no significant effect on the sensitivity of any component of the CAP to lidocaine. 4. Tetrodotoxin (TTX, 10 microM) blocked completely both the A wave and the C wave of the CAP in either vagus or saphenous nerves. 5. In saphenous nerve preparations the A wave was blocked by lower concentrations of TTX than the C wave or any component of the CAP in vagus nerve preparations which suggests that somatosensory A fibres express a different sub-type of TTX-sensitive voltage-gated sodium channel (VGSC) than somatosensory C-fibres or visceral sensory fibres. 6. Chemical activation of VGSCs with veratridine (10 or 50 microM) induced a depolarization in either nerve. The depolarization induced by 50 microM veratridine was blocked by 10 microM TTX. 7. Although TTX-insensitive VGSCs are expressed by some vagal and some somatosensory neurones they do not appear to be expressed functionally in the axons.     

Effect of prolonged incubation with copper on endothelium-dependent relaxation in rat isolated aorta

1 We investigated the effects of prolonged exposure to copper (Cu(2+)) on vascular functioning of isolated rat aorta. 2 Aortic rings were exposed to CuSO(4) (3-24 h) in Dulbecco's modified Eagle medium with or without 10% foetal bovine serum (FBS) and then challenged with vasoconstrictors or vasodilators in the absence of Cu(2+). 3 Exposure to 2 micro M Cu(2+) in the absence of FBS did not modify the response to phenylephrine (PE) or acetylcholine (ACh) in aortic rings incubated for 24 h. Identical exposure in the presence of FBS increased the contractile response to 1 micro M PE by 30% (P<0.05) and impaired the relaxant response to 3 micro M ACh or 1 micro M A23187 (ACh, from 65.7+/-7.1 to 6.2+/-1.1%, n=8; A23187, from 74.6+/-8.2 to 12.0+/-0.8%, n=6; P<0.01 for both). Cu(2+) exposure did not affect the relaxant response to NO-donors. 4 Impairment of vasorelaxation appeared 3 h after incubation with 2 micro M Cu(2+) and required 12 h to attain a steady state. Vasorelaxation to ACh was partially restored by 1 mM tiron (intracellular scavenger of superoxide ions; maximum relaxation 34.2+/-6.4%, n=10, P<0.01 vs Cu(2+) alone), whereas catalase, superoxide dismutase or cycloheximide were ineffective. 5 Twenty-four hour-exposure to 2 micro M Cu(2+) did not affect endothelium integrity or eNOS expression, and increased the Cu content in arterial rings from 6.8+/-1.1 to 18.9+/-2.9 ng mg(-1) wet weight, n=8; P<0.01. 6 Our results show that, in the presence of FBS, prolonged exposure to submicromolar concentrations of Cu(2+) impaired endothelium-dependent vasorelaxation in aortic rings, probably through an intracellular generation of superoxide ions. British Journal of Pharmacology (2002) 136, 1185-1193     

Mutations inducing divergent shifts of constitutive activity reveal different modes of binding among catecholamine analogues to the beta(2)-adrenergic receptor

1. We compared the changes in binding energy generated by two mutations that shift in divergent directions the constitutive activity of the human beta(2) adrenergic receptor (beta(2)AR). 2. A constitutively activating mutant (CAM) and the double alanine replacement (AA mutant) of catechol-binding serines (S204A, S207A) in helix 5 were stably expressed in CHO cell lines, and used to measure the binding affinities of more than 40 adrenergic ligands. Moreover, the efficacy of the same group of compounds was determined as intrinsic activity for maximal adenylyl cyclase stimulation in wild-type beta(2)AR. 3. Although the two mutations had opposite effects on ligand affinity, the extents of change were in both cases largely correlated with the degree of ligand efficacy. This was particularly evident if the extra loss of binding energy due to hydrogen bond deletion in the AA mutant was taken into account. Thus the data demonstrate that there is an overall linkage between the configuration of the binding pocket and the intrinsic equilibrium between active and inactive receptor forms. 4. We also found that AA mutation-induced affinity changes for catecholamine congeners gradually lacking ethanolamine substituents were linearly correlated to the loss of affinity that such modifications of the ligand cause for wild-type receptor. This indicates that the strength of bonds between catechol ring and helix 5 is critically dependent on the rest of interactions of the beta-ethanolamine tail with other residues of the beta(2)-AR binding pocket.     

Ribose-modified nucleosides as ligands for adenosine receptors: synthesis, conformational analysis, and biological evaluation of 1'-C-methyl adenosine analogues

1'-C-Methyl analogues of adenosine and selective adenosine A(1) receptor agonists, such as N-[(1R)-1-methyl-2-phenylethyl]adenosine ((R)-PIA) and N(6)-cyclopentyladenosine, were synthesized to further investigate the subdomain that binds the ribose moiety. Binding affinities of these new compounds at A(1) and A(2A) receptors in rat brain membranes and at A(3) in rat testis membranes were determined and compared. It was found that the 1'-C-methyl modification in adenosine resulted in a decrease of affinity, particularly at A(1) and A(2A) receptors. When this modification was combined with N(6) substitutions with groups that induce high potency and selectivity at A(1) receptors, the high affinity was in part restored and the selectivity was increased. The most potent compound proved to be the 1'-C-methyl analogue of (R)-PIA with a K(i) of 23 nM for the displacement of [(3)H]CHA binding from rat brain A(1) receptors and a > 435-fold selectivity over A(2A) receptors. In functional assays, these compounds inhibited forskolin-stimulated adenylate cyclase with IC(50) values ranging from 0.065 to 3.4 microM, acting as full agonists. Conformational analysis based on vicinal protonminus signproton J-coupling constants and molecular mechanics calculations using the MM2 force field proved that the methyl group on C1' in adenosine has a pronounced impact on the furanose conformation by driving its conformational equilibrium toward the north, gamma+, syn form.     

Antihypertensive,vasodilator and antioxidant effects of a vinifera grape skin extract

Cumulative evidence suggests that moderate wine consumption exerts a cardioprotective effect. We investigated the occurrence of an antihypertensive effect of an alcohol-free hydroalcoholic grape skin extract (GSE) obtained from skins of a vinifera grape (Vitis labrusca) in experimental rodent hypertension models. The vasodilator effect of GSE (polyphenols concentration 55.5 mg g(-1)) was also assessed in the isolated mesenteric vascular bed of Wistar rats and the antioxidant effect was studied on lipid peroxidation of hepatic microsomes. Oral administration of GSE significantly reduced systolic, mean and diastolic arterial pressure in Wistar rats with desoxycorticosterone acetate-salt and N(G)-nitro-L-arginine methyl ester (L-NAME) induced experimental hypertension. In the rat isolated mesenteric vascular bed pre-contracted with norepinephrine, bolus injections of GSE induced endothelium-dependent vasodilatation that was substantially inhibited by L-NAME, but not by indometacin, tetraethylammonium or glibenclamide. Lipid peroxidation of hepatic microsomes estimated as malondialdehyde production was concentration-dependently inhibited by GSE. In conclusion, the antihypertensive effect of GSE might be owing to a combination of vasodilator and antioxidant actions of GSE. These findings also suggest that the beneficial effect of moderate red wine consumption could be owing to an antihypertensive action induced by compounds occurring in the skin of vinifera grapes.     

Cardiac and thermoregulatory effects of instilled particulate matter-associated transition metals in healthy and cardiopulmonary-compromised rats

Particulate matter air pollution has been associated with cardiopulmonary morbidity and mortality in many recent epidemiological studies. Previous toxicological research has demonstrated profound cardiac and thermoregulatory changes in rats following exposure to residual oil fly ash (ROFA), a combustion-derived particulate. The response to ROFA appeared biphasic, consisting of both immediate (0-6 h) and delayed (24-96 h) bradycardia and hypothermia. Other studies have demonstrated that much of the pulmonary toxicity of ROFA was caused by its constitutive transition metals, namely, Fe, Ni, and V. This study examined the contributions of these metals to the observed cardiac and thermoregulatory changes caused by ROFA in conscious, unrestrained rats. Prior to exposure, each animal was surgically implanted with a radiotelemetry device capable of continuously monitoring heart rate, electrocardiographic, and core temperature data. Individual metals were intratracheally instilled in healthy rats (n = 4 per metal species) and in rats with monocrotaline (MCT; 60 mg/kg)-induced pulmonary hypertension (n = 10 per metal species); combinations of metals were instilled in MCT-treated rats only (n = 6 per combination of metal species). Metals were administered in doses equivalent to those found in the highest dose of ROFA used in previous studies, that is, 105 microg Fe(2)(SO(4))(3), 263 microg NiSO(4), and 245 microg VSO(4). Healthy and MCT-treated rats demonstrated similar responses to metals. Fe caused little response, whereas V caused marked bradycardia, arrhythmogenesis, and hypothermia immediately following instillation and lasting approximately 6 h. Ni caused no immediate response, but induced a delayed bradycardia, arrhythmogenesis, and hypothermia that began approximately 24 h after instillation and lasted for several days. When instilled in combination, Ni appeared to exacerbate the immediate effects of V, whereas Fe attenuated them. These data suggest that the biphasic response to instilled ROFA may result from a summation of the temporally different effects of V and Ni.     

Effect of acupuncture in the treatment of seasonal allergic rhinitis: a randomized controlled clinical trial

The clinical efficacy and safety of acupuncture in the treatment of Seasonal Allergic Rhinitis (SAR) was evaluated by employing a two-phase crossover single-blind clinical trial. Thirty subjects were randomly assigned to two groups with 17 and 13 subjects respectively and treated with real or sham acupuncture (three times per week) for four consecutive weeks and then a crossover for treatments for a further four weeks without a washout period. The administration of real acupuncture treatment was guided by a syndrome differentiation according to Chinese Medicine Theory. Subjects were assessed by various criteria before, during and after the treatments. Outcome measures included subjective symptom scores using a five-point scale (FPS), relief medication scores (RMS) and adverse effect records. Twenty-six (26) subjects completed the study. There was a significant improvement in FPS (nasal and non-nasal symptoms) between the two types of acupuncture treatments. No significant differences were shown in RMS between the real acupuncture treatment group and the sham acupuncture treatment group. No side effects were observed for both groups. The results indicate that acupuncture is an effective and safe alternative treatment for the management of SAR.