Hydroxyl radical concentrations measured in ambient air

Diurnal variations in the hydroxyl radical concentration of ambient air were measured for the first time by the technique of laser-induced fluorescence.     

THE USE OF ELECTROCARDIOGRAPHY IN THE DIAGNOSIS OF POOR RACING PERFORMANCE IN THE HORSE

Electrocardiograms were reocrded from 153 racehorses and 10 Olympic three-day-event horses. The horses were then grouped into those presented for routine examination, those in which there was a complaint of poor performance, those going to the Montreal Olympics, and those with upper respiratory tract abnormalities. When the ECGs of the four groups were compared on the basis of detection of abnormality, it was found that 93.2% of the poor performance group showed abnormalities of various types. The routine examination group showed 21.1% of horses with abnormal ECGs, and over half of these have been followed to the point where it can be said they raced unsuccessfully. In particular, this applied to those horses with T wave abnormalities in 4 or more leads, and to those with intraatrial block. There were significant T wave changes in 50% of the Olympic horses, and 43.7% of horses with laryngeal hemiplegia showed abnormality. While it can be concluded that T wave changes are highly significant findings in an ECG, it is also true that modification of the training programme is a way of helping trainers to get the best out of horses which might otherwise have a serious limitation of their performance potential.     

Evaluation of jitter by stimulated single-fiber electromyography in normal dogs

Single-fiber electromyography (SFEMG), a technique used to investigate neuromuscular transmission, has been described previously in the pelvic limb of dogs. Because preferential involvement of isolated muscle groups can occur in disorders of neuromuscular transmission, SFEMG was done in the peroneus longus (PL), extensor carpi radialis (ECR), and orbicularis oculi (OO) muscles of 10 adult, clinically normal dogs. Jitter was calculated as the mean absolute value of the consecutive differences in latency of 50 single muscle fiber action potentials after stimulation of intramuscular nerve bundles at the level of the motor point in at least 20 muscle fibers per muscle. Bilateral recordings were performed in 3 dogs. Mean jitter values were determined for each muscle, and differences among muscle groups and among dogs were compared. The upper limits of mean consecutive difference (mean plus 3 standard deviations) for the PL, ECR, and OO muscles were 21.94, 22.53, and 23.39 micros, respectively, and the upper limit of mean consecutive difference for individual muscle fibers in the respective fiber pools was 28.62, 36.39, and 35.68 micros. Jitter values for the ECR and OO were significantly higher than the jitter value for the PL muscle (P < .05). Significant differences among muscles or dogs or between sides were not observed for the ECR. Significant differences among dogs were observed for OO jitter values and were attributed to extremely low jitter values in 1 dog. Significant differences were demonstrated between sides for the PL and were attributed to small sample size. Results of this study provide normative data that can be used in the application of the stimulated SFEMG technique to dogs with suspected disorders of neuromuscular transmission.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Myxozoans infecting the sharptooth catfish, Clarias gariepinus in the Okavango River and Delta, Botswana, including descriptions of two new species, Henneguya samochimensis sp. n. and Myxobolus gariepinus sp. n

During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.