Caffeine dose response.

<p>Histogram of Indo-1 response to increasing concentrations of caffeine in adenovirally-transduced equine myotubes. Results show mean (+/−1 SEM) derived from 40 myotubes from 2 control horses sequentially exposed to 5, 10 and 20 mM caffeine at 2 and 3 weeks’ differentiation.</p

Effect of dantrolene on calcium transients.

<p>A) Depolarization with 60 mM KCl and 20 mM caffeine in normal buffer, followed by exposure to sequential exposures to caffeine in the presence of 10 µM dantrolene. B) The amplitude of the caffeine transient in the absence or presence of dantrolene. Note that dantrolene almost completely inhibits the ability of the myotubes to respond to caffeine (p<0.05) and lowers the cytoplasmic calcium concentration of resting myotubes. C) Indo-1 fluorescence at increasing calcium concentration, in the presence or absence of 10 µM dantrolene. Note that there was no direct effect of dantrolene on Indo-1 fluorescence.</p

Depolarisation with KCl.

<p>Representative experiment where skin-derived equine myotubes were subjected repeatedly to depolarization with 60 mM KCl (red line). 10 mM caffeine responses (blue line) are shown for comparison. Note that responses are reproducible and near maximal within approximately 4 minutes.</p

Management regimes used for prevention of ERS reported by 22 Standardbred trainers in Sweden with one or more horses with ERS in training from March 2006- February 2007.

<p>Management regimes used for prevention of ERS reported by 22 Standardbred trainers in Sweden with one or more horses with ERS in training from March 2006- February 2007.</p

Descriptive statistics of continuous horse-level and performance variables for Swedish Standardbred trotters with (cases) and without (controls) exertional rhabdomyolysis syndrome.

<p>sd  =  standard deviation; iqr  =  inter-quartile range.</p

Pre- and post exercise muscle enzyme activites.

<p>Graph illustrating the pre and post exercise (a) CK activity and (b) AST activity for each GYS1 genotype (n = 4) (HH = homozygotes, HR = heterozygote, RR = control).</p

Results of multivariable conditional logistic regression analysis of variables associated with exertional rhabdomyolysis syndrome in Swedish Standardbred trotters.

<p>Models were derived using a stepwise forward selection approach with variables retained in the model if they were significantly associated with ERS (P_Wald <0.05) and/or improved model fit (P_LRS <0.05). Pwald =  Wald test P-value; P_LRS  =  Likelihood Ratio Statistic P-value.</p

Signalment of all horses participating in each section of the study, showing no significant differences between matched groups.

<p>Signalment of all horses participating in each section of the study, showing no significant differences between matched groups.</p

Muscle fibre type distributions.

<p>Boxplots illustrating the muscle fibre type composition of horses homozygous (HH) (n = 4), heterozygous (HR) (n = 8) and control horses (RR) (n = 6). * Denotes significant differences between individual groups (p<0.05) following post- hoc analysis.</p

Resting muscle enzyme activities.

<p>Box plots illustrating the resting (a) CK activity and (b) AST activity for each GYS1 genotype (n = 8) (HH = homozygotes, HR = heterozygote, RR = control) * Denotes significant differences between individual groups (p<0.05) following post- hoc analysis.</p