Urethral pressure profiles (UPPs) were recorded in ten adult healthy male cats before and after administration of either phenoxybenzamine, diazepam, nifedipine or xylazine. A significant decrease (p < 0.05) in urethral pressure at the level of the prostate was observed following treatment with all drugs. Xylazine produced a significant decrease in urethral pressure 4 to 7 cm from the tip of the penis in healthy male cats. None of the drugs used decreased urethral pressure in the zones of pure striated muscle or pure smooth muscle in these cats, making current recommendations for pharmacological management of urethral spasm suspect. Further studies are necessary to evaluate clinical cases of urethral spasm and to study the effects of these drugs on the urethral pressure of cats suffering from this spasm.

The association between ocular squamous cell tumors and various measures of solar radiation was evaluated for 2,775 contemporaneous Hereford cattle. The animals were from 34 herds located in 21 states in the United States and in one Canadian province. Examinations and photographs were made of the eyes of all cows and heifers in a herd; 33 herds were examined between June and August 1957 and 1 herd was examined in 1958. Solar radiation was measured by altitude and mean annual hours of sunshine applying to an individual herd, and global radiation, a cloudiness index, and elevation of nearby National Weather Service stations. All measures of solar radiation provided evidence of a significant association between increasing risks of developing cancer eye and increasing levels of radiation; adjustments were made for possible confounding effects of age and corneoscleral pigmentation. Associations were evident whether affliction was defined as the occurrence of any type of tumor (ie, plaque, papilloma, or carcinoma), or as the occurrence of only papilloma or carcinoma. Average ages of affected cattle also tended to be lower at high radiation levels than at low levels, further supporting the hypothesis that solar radiation has an important role in the development of this disease. In view of the heritability of eye pigmentation and its inhibitory effect on lesions, cancer eye may be controlled by selective breeding for increased pigmentation in and around the eye to afford protection against the harmful effects of incident UV radiation.

Sodium hyaluronate reduces adhesions after tendon repair in rodents and dogs, and has been used in limited clinical trials in people. To evaluate its effect on tendon healing and adhesion formation in horses and to compare these effects with those of a compound of similar viscoelastic properties, a study was performed in horses, using a model of collagenase injection in the flexor tendons within the digital sheath. Eight clinically normal horses were randomly allotted to 2 groups. Adhesion formation between the deep digital flexor tendon and the tendon sheath at the pastern region was induced in the forelimbs of all horses. Using tenoscopic control, a 20-gauge needle was inserted into the deep digital flexor tendon of horses under general anesthesia and 0.2 ml of collagenase (2.5 mg/ml) was injected. The procedure was repeated proximally at 2 other sites, spaced 1.5 cm apart. A biopsy forceps was introduced, and a 5-mm tendon defect was created at each injection site. Group-A horses had 120 mg of sodium hyaluronate (NaHA) gel injected into the tendon sheath of one limb. Group-B horses had methylcellulose gel injected at the same sites. The contralateral limbs of horses in both groups served as surgical, but noninjected, controls. Horses were euthanatized after 8 weeks of stall rest. Ultrasonographic evaluation revealed improved tendon healing after NaHA injection, but no difference in peritendinous adhesion formation. Tendon sheath fluid volume and hyaluronic acid (HA) content were greater in NaHA-treated limbs. Gross pathologic examination revealed considerably fewer and smaller adhesions when limbs were treated with NaHA. However, significant difference in pull-out strengths was not evident between NaHA-treated and control limbs. Histologically, the deep digital flexor tendon from the NaHA-treated limbs had reduced inflammatory cell infiltration, improved tendon structure, and less intratendinous hemorrhage. Treatment with methylcellulose had no significant effect on tendon healing, adhesion size, quantity, or strength or on the volume and composition of the tendon sheath fluid. Sodium hyaluronate, administered intrathecally, appears to have a pharmaceutically beneficial action in this collagenase-induced tendinitis and adhesion model in horses.

The role of L-asparaginase (L-ASP) in limiting signs of methotrexate (MTX) toxicosis was studied. Eight dogs were randomly allotted to 2 groups of 4 dogs. All dogs were given 400 IU of L-ASP/kg of body weight IM, on day 1. On day 10, group-1 dogs were given 3 mg of MTX/kg, IV, and group-2 dogs were given 6 mg of MTX/kg, IV. All dogs were given 400 IU of L-ASP/kg, IM, 24 hours later (on day 11). One group-2 dog was euthanatized on day 16 because of severe gastrointestinal signs that were unresponsive to treatment. A second dose of MTX, identical to that given on day 10, was given on day 20 to each surviving dog, followed by L-ASP on day 21. On day 67, the 7 surviving dogs were given 3 mg gf MTK/kg, IV. Adverse reactions observed were vomiting diarrhea, and weight loss. Gastrointestinal side effects of MTX were not attenuated with L-ASP and would be a serious limitation to use of MTX administered at an intermediate dose in the treatment of lymphoma in dogs.

To evaluate the use of technetium pertechnetate (99mTcO4) as a means of estimating gastric mucosal integrity, nuclear images of the empty stomach were obtained from 6 dogs at 20, 40, 60, 120, 180, and 240 minutes after IV administration of the radiopharmaceutical. Blood and gastric secretion samples were collected during the same time intervals. The left lateral-view image of the stomach was used to calculate the relative fraction of the dose in the stomach and the count density ratio. Between 20 and 40 minutes and 40 and 60 minutes, significant differences (P < 0.001) were apparent in the amount of 99mTcO4 in the stomach. Blood concentration of 99mTcO4 decreased significantly (P < 0.001), whereas gastric secretion concentration increased significantly (P < 0.001) over time. Qualitative assessment of the gastric nuclear scans and the statistical analytic results indicated that the optimal time for imaging the canine stomach was between 40 and 60 minutes after radiopharmaceutical administration. In a second study, the same dogs were pretreated with the H2-receptor antagonist cimetidine and the cholinergic antagonist glycopyrrolate to block gastric secretions. Over time, changes in the relative dose fraction in the stomach and the density ratio were the same as values obtained during the experiment performed without use of cimetidine and glycopyrrolate. Results of the study indicate that nuclear imaging with 99mTcO4 outlines normal canine gastric mucosa and that pretreatment with cimetidine and glycopyrrolate has no effect on the quality of the gastric image.

Sixty-nine specific pathogen-free male Wistar rats approximately eight weeks of age were used to evaluate the efficacy of an attentuated strain of sialodacryoadenitis (SDA) virus in providing protection against infection on subsequent challenge with virulent SDA virus. Fifty-four animals were inoculated intranasally with approximately 10-1.5 median cell culture infectious doses of the 25th passage of SDA virus in L-2 cells. Randomly-selected vaccinated animals were killed in order to evaluate the safety and efficacy of attenuated virus by histopathological examination of the salivary glands, lacrimal glands, and lower respiratory tract, and titration of sera for antibody to SDA virus. At three months and six months post-vaccination (pv), animals were selected at random and challenged with virulent SDA virus. Seronegative, age-matched animals were also challenged, and served as controls. In animals examined at six to ten days pv, lesions were absent in submandibular and parotid salivary glands and lacrimal glands, but transient lesions were present in major airways of the lower respiratory tract. In a comparison of the incidence and extent of lesions, and antibody titers in challenged vaccinates and seronegative controls, lesions were minimal or absent in vaccinates compared to challenged naive rats, particularly in animals inoculated at three months pv. In addition, antibody titers in challenged vaccinates were much higher than were postinoculation titers in inoculated controls. In a comparison of lesions in salivary and lacrimal glands in vaccinated and control animals challenged at six months pv, there was a significant reduction in the number of animals without lesions in the vaccinated group (p = < 0.0001). Based on the incidence of lesions in target tissues and the marked antibody response in vaccinates on challenge with virulent SDA virus, it was concluded that prior inoculation with the attenuated strain of SDA virus provided a significant level of protection for up to six months postvaccination.

Pulmonary function tests were performed on seven adult dairy cows with an expanded tung field (ExLF) and the results were compared to the values from seven cows with normal lung fields. The cows with ExLF had an increased functional residual capacity (FRC) and end-tidal N2 concentration of the final breath of the multiple-breath N2 washout (FET(N2),fb), and an abnormal distribution of ventilation. The measurements of ventilation and gas exchange and pulmonary mechanics did not differ between the two groups. Postmortem examination of the lungs of five of the cows in each group indicated the cows with ExLF had a bronchiolitis with varying degrees of goblet cell hyperplasia, epithelial cell hyperplasia and metaplasia, smooth muscle hypertrophy, inflammatory cell infiltrate, vascular thickening, peribronchiolar fibrosis, and a mild overinflation of the lung. A histopathological score, based on the preceding indices and bronchus-associated lymphoid tissue, was correlated with FRC, FET(N2),fb, the lung clearance index and pulmonary resistance. There were no correlations between the histopathological score and any of the measures of ventilation and gas exchange.

Age, breed, and gender distributions of 168 horses with umbilical hernia treated at the University of Pennsylvania School of Veterinary Medicine were analyzed to determine risk factors for this disease. For the 3 breeds that constituted the largest proportion of hospital and case populations, Thoroughbred, Standardbred, and Quarter Horse, the overall ratio of females to males was 1.63. In a hospital population of the same age group, 0 to 48 months, the female to male ratio was 0.93. Compared with males, females were at significantly higher risk for umbilical hernia after adjustment for breed and age (odds ratio, 2.01; 99% confidence interval, 1.31 to 3.10; P = 0.00002). Of the 2 major breeds, Thoroughbreds were at greater risk than Standardbreds for umbilical hernia, after adjustment for gender and age (odds ratio, 1.80; 99% confidence interval, 1.10 to 2.95; P = 0.0020). The results provide information about a common congenital defect in horses that can be used for future genetic research.

Comparisons of the MacKay-Marg and Tono-Pen applanation tonometers in open and closed in vitro systems were made for the eyes of cats. Both instruments significantly underestimated intraocular pressure (IOP) vs direct manometry (P < 0.001), but in readily predictable manner, with high coefficients of determination (r2 = 0.99). For tonometer 1 (MacKay-Marg), calculated actual IOP = 1.36 X (MacKay-Marg measurement) - 1.67 mm of Hg; and for tonometer 2 (Tono-Pen), calculated actual IOP = 1.37 X (Tono-Pen measurement) + 0.8 mm of Hg, using measurements from 11 enucleated eyes. In vivo comparisons were initially made in 81 clinically normal eyes (n = 41 cats) by applying the Tono-Pen first followed by the MacKay-Marg. Compared with the MacKay-Marg, the Tono-Pen significantly (P < 0.001) underestimated IOP in these cats. When the order of tonometer applanation was subsequently reversed in 73 clinically normal eyes (n = 37 cats) the Tono-pen again significantly (P < 0.001) underestimated IOP, compared with the MacKay-Marg. Alterations in tonometer order did not result in significant differences in measured IOP for the MacKay-Marg when compared with itself, but Tono-Pen measurements were significantly (P < 0.05) less when its use followed rather than preceded, that of the MacKay-Marg. Mean (+/- SD) IOP in clinically normal cats when each tonometer was used first was 22.6 +/- 4.0 mm of Hg (range, 14 to 32 mm of Hg) for the MacKay-Marg and 19.7 +/- 5.6 mm of Hg (9 to 31 mm of Hg) for the Tono-Pen. The mean (+/- SD) absolute value of the differences between MacKay-Marg measurements and those obtained by use of the Tono-Pen was 3.2 +/- 3.1 (range, 0 to 13 mm of Hg difference).

Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P < 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was > 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.