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41.
SUMMARY The presence of abnormal T waves in three or more electrocardiographic leads has been used to diagnose the cause of poor race performance in horses. This study investigated the relationship between previous racing performance in Standardbred horses and T waves, and the effect of training on the T wave. Thirty-two horses were electrocardiographed in two Sydney racing stables. Sixteen horses (50%) had ECGs with three or more leads with abnormal T waves, and these horses had won more races, had a greater ratio of wins per start and a greater number of dollars earned per start than horses with less than three abnormal T waves (P < 0.05). Horses with abnormal T waves also had significantly faster racing times (P < 0.01). There were significant (P < 0.01) correlations between the number of abnormal T waves and both number of wins (R = 0.47) and dollars earned per start (R = 0.45). Fastest winning mile rate was also negatively correlated with number of leads with abnormal T waves (R =?0.52, P < 0.01). Twenty two horses were also electrocardiographed within seven days of good racing performance. The mean number of abnormal T waves was 2.7 ± 0.41, and the mean T wave amplitude in the four chest leads (CV, CR, CL, CF) was 0.9 ± 0.15 mV. Thirteen horses (59%) had abnormal T waves in three or more leads. The effect of training on the T wave was also investigated in nine previously untrained and unraced Standardbred racehorses. There were significant effects of training (P < 0.01) on the number of abnormal T waves and mean chest lead T wave amplitude. These increases occurred in the second phase of training during which faster exercise, race trials and racing were conducted. We concluded that abnormal T waves are a common finding in the race-fit Standardbred horse, and can be found in more than 50% of horses currently performing well in races. In addition, chest lead T waves become more positive after training. 相似文献
42.
CAROL A. NEFF-DAVIS LLOYD E. DAVIS THOMAS E. POWERS 《Journal of veterinary pharmacology and therapeutics》1978,1(3):233-240
The tissue distribution of tetraethylammonium (TEA), a highly polar drug which does not undergo biotransformation, was studied in intact and nephrectomized dogs and goats. Values for β, the overall elimination rate constant, were significantly reduced by nephrectomy but species differences were not significant. Values for apparent specific volume of distribution (V'd ) were unexpectedly large and tissue to plasma ratios were 4.0 and 5.0 in the nephrectomized goat and dog, respectively. The distribution of TEA to various tissues followed closely the expected pattern of regional blood flow, although TEA attained concentrations in liver, heart, lungs and viscera in excess of the concentration in the plasma. 相似文献
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R. G. THOMAS 《Grass and Forage Science》1981,36(2):121-125
Flowering behaviour of plants of six cultivars of Trifolium repens (Kent Wild White, Grasslands Huia, S100, Blanca, Olwen and Milkanova) growing in field plots at the Grassland Research Institute, Hurley, was recorded in mid-July. Half of each plot had been defoliated in early May, the other half in mid-June. In all cultivars defoliated in May, inflorescence initiation had stopped even though the natural photoperiod at that time was well above the critical daylength for initiation Defoliation in mid-June had led to a renewal of inflorescence initiation in all cultivars.
The results confirm that the stimulatory effect of defoliation on inflorescence initiation in plants that have stopped initiation in long days, which has previously been observed in Grasslands Huia in controlled environments, also occurs in the field and in other cultivars. 相似文献
The results confirm that the stimulatory effect of defoliation on inflorescence initiation in plants that have stopped initiation in long days, which has previously been observed in Grasslands Huia in controlled environments, also occurs in the field and in other cultivars. 相似文献
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R. RANDY BASINGER DVM DENNIS N. ARON DVM DiplomateACVs DENNIS T. CROWE DVM DiplomateACVs P. THOMAS PURINTON DVM PhD 《Veterinary surgery : VS》1987,16(6):427-434
Experimentally induced osteofascial compartment syndrome (OFCS) has been reported in the craniolateral compartment of the canine crus. In this study, anatomic dissections and contrast radiographs were used to describe three additional osteofascial compartments in canine limbs. Experimental OFCS was produced in four different compartments, and caused muscle and nerve pathology in each. When compartment pressures were evaluated in traumatized animals, moderate elevations in compartment pressures were found. A compartment syndrome that developed in one dog was surgically decompressed, returning elevated pressures to a safe level. 相似文献
48.
THOMAS K. DAY DVM MS Diplomate ACVA WILLIAM W. MUIR III DVM PhD Diplomate ACVA 《Veterinary surgery : VS》1994,23(3):206-212
Complete atrioventricular (AV) block was produced in 32 chloralose-anesthetized autonomically intact dogs to determine the effects of halothane, enflurane, and isoflurane on supraventricular and ventricular rate. Halothane (n = 17), enflurane (n = 6), and isoflurane (n = 9) were administered in three separate experiments in sequential minimum alveolar concentration (MAC) multiples of 0.5, 1.0, 1.5, 2.0, 1.5, and 1.0. Supraventricular rate, ventricular rate, and mean arterial blood pressure (MAP) were measured and recorded at baseline and after a 20-minute equilibration period of each inhalation anesthetic at each MAC multiple. Increasing concentrations of enflurane and isoflurane significantly decreased supraventricular rate ( P < .05). Ventricular rate was not significantly changed by sequential MAC multiples of halothane, enflurane, and isoflurane. Increasing concentrations of halothane, enflurane, and isoflurane significantly decreased MAP with enflurane producing the most significant decrease ( P < .05). Ventricular arrhythmias occurred in 5 of 17 dogs anesthetized with halothane and 1 of 9 dogs anesthetized with isoflurane. Inhalation anesthesia can significantly decrease supraventricular rate and MAP, does not alter ventricular rate, and can produce ventricular arrhythmias in dogs with complete AV block. 相似文献
49.
SUMMARY: Vascular access ports were surgically placed, first in rabbits maintained under laboratory conditions, and then in koalas maintained in a wildlife park. The ports remained patent for 9 months in rabbits and for up to 13 months in the koalas and were removed successfully. They allowed collection of blood samples without assistance or disturbance in koalas, and without stress as reflected by plasma cortisol concentration. The use of retention rings on the cannula tubing is recommended. 相似文献
50.
Large undisturbed soil cores (20 cm diam. × 25–30 cm long) were irrigated at rates of 0.5–4 cm h?1 with 0.005 M CaCl2 solution labelled with 3HOH. The cores were used at varying initial water contents and flow in all cases was unsaturated. Breakthrough curves for Cl and 3HOH were markedly asymmetric and unlike those reported for columns of packed aggregates. The data could be satisfactorily described using a density distribution function of the logarithm of cumulative drainage D. The mean and standard deviation of In D were estimated by a curve-fitting procedure from Cl and 3HOH effluent concentrations in each core. The mean pore water velocity and fraction of the soil water that participated in solute transport (the mobile volume) were also calculated. The apparent velocity of Cl movement was always greater than that of 3HOH which suggested that the mobile volume involved in convective and diffusive transport of Cl was less than that for 3HOH. We suggest that Cl and 3HOH diffused at different rates out of flowing water films in a relatively few large conducting channels into essentially immobile water within the surrounding soil matrix. The difference in mobile volume for Cl and 3HOH was used to calculate the perimeter of voids in any horizontal cross-section of the soil through which water flowed, assuming a planar interface between the mobile and immobile water. 相似文献