The effect of fungi on the growth of body organs in mice was investigated. Single, intraperitoneal injections of yeasts (Cryptococcus albidus, Saccharomyces cerevisiae, Schizosaccharomyces octosporus) or molds (Aspergillus niger, Geotrichum candidum, Mucor haemalis) induced an increase in the mass of seminal vesicles and coagulating glands independent of whole body weight changes in mice.

Six Rocky Mountain bighorn sheep were raised in captivity from birth (n = 5) or taken from the wild as a lamb (n = 1). After the bighorn sheep were in captivity for over a year, 6 clinically normal domestic sheep were placed on the 2 ha of pasture on which the bighorn sheep were kept. Nasal swab specimens were obtained from all sheep at the time the domestic sheep were introduced. Pasteurella haemolytica was isolated from swab specimens obtained from 4 of 6 domestic sheep, but not from specimens obtained from the bighorn sheep. All 6 bighorn sheep died of acute hemorrhagic pneumonia after exposure to domestic sheep. Death in the bighorn sheep occurred on days 4, 27, 27, 29, 36, or 71 after initial exposure to domestic sheep. Pasteurella haemolytica was isolated from respiratory tract tissue specimens of all bighorn sheep at the time of death. None of the domestic sheep were clinically ill during the study. At the end of the study, 3 of 6 domestic sheep were euthanatized, and at necropsy, P haemolytica was isolated from 2 of them. The most common serotypes in bighorn and domestic sheep were P haemolytica T-3 and A-2. Other serotypes isolated included P haemolytica A-1, A-9, and A-11 in bighorn sheep and A-1 in domestic sheep. On the basis of results of this study and of other reports, domestic sheep and bighorn sheep should not be managed in proximity to each other because of the potential fatal consequences in bighorn sheep.

Serum vitamin E and blood glutathione peroxidase values were determined in 40 horses with a histologically confirmed diagnosis of degenerative myeloencephalopathy and in 49 age-matched control horses with normal neurologic function. Significant differences were not detected in serum vitamin E or blood glutathione peroxidase values between horses affected with degenerative myeloencephalopathy and control horses. These findings fail to support a reported role of vitamin E deficiency as a cause of equine degenerative myeloencephalopathy.

Pilus-mediated adherence is a virulence attribute of Moraxella bovis. Several pilus types have been shown to exist among strains of this bacterium, but correlation between pilus type and specific field cases of the disease has not been done. During the summer of 1987, an epizootic of infectious bovine keratoconjunctivitis was reported in 7 Iowa counties. Eight isolates of M bovis were secured from 12 episodes studied. All 8 of the isolates were nearly homogeneous in biochemical properties and had the same plasmid biotype. Pilus typing performed by immunofluorescence and immunogold electron microscopy identified a single new pilus type among 5 of the 8 isolates. This pilus type was identified in field cases that developed within a narrow time frame and over large distances. The implication of these findings is that infectious bovine keratoconjunctivitis epizootics may be associated with emergence of a novel pilus type, and that rapid dissemination over wide distances can occur, presumably by transportation of carrier cattle.

The influence of distention (high baseline intraluminal pressure) and neostigmine methylsulfate on intestinal vascular resistance, oxygen uptake, and intraluminal pressure changes (rhythmic contractions) was studied in terminal jejunal segments which were perfused at a constant rate, in 16 anesthetized ponies. When baseline intraluminal pressure was increased to 10 mm of Hg, the intestinal vascular resistance and amplitude of rhythmic contractions were increased. Neostigmine induced cyclic increases in amplitude of rhythmic contractions whether intraluminal pressure was 0 or 10 mm of Hg. Neostigmine also increased intestinal oxygen uptake at intraluminal pressures of 0 mm of Hg, but not at 10 mm of Hg, and vascular resistance was not altered at either intraluminal pressure. The results indicate that intestinal hemodynamics are adversely affected by distention. Further, neostigmine did not adversely affect intestinal hemodynamics while increasing rhythmic contractions, suggesting that neostigmine may be useful in the treatment of ileus in equids.

Twenty-one mixed-breed pony foals, reared and maintained under parasite-free conditions, were used to test the efficacy of ivermectin in oral drench and paste formulations (200 microgram/kg) against 11-day-old migrating larvae of Parascaris equorum. Three replicates of 4 foals and 3 replicates of 3 foals were formed on the basis of age. Foals in replicates of 4 were randomly allocated to be indicators, or to receive vehicle (control) or ivermectin paste or ivermectin liquid. Foals in replicates of 3 were randomly allocated to receive vehicle or ivermectin paste or ivermectin liquid. The recovery of larvae from the lungs, liver, and small intestines of the indicator foals showed that 99.9% of the larvae were in the lungs 11 days after inoculation (day 0 of treatment). The recoveries of larvae from lungs and small intestines of controls at 25 days after inoculation indicated that all larvae had migrated to the small intestine by this time. The mean length of larvae recovered from the lungs (11 days after inoculation) was 0.87 mm; the mean length of those recovered from the small intestine (25 days after inoculation) was 3.65 mm. Using larvae recovered from small intestinal contents for calculations, ivermectin in both formulations was 100% effective against 11-day P equorum (P less than 0.01, compared with control group geometric mean of 1498.4).

Wick catheters were used to measure intracompartmental pressures of the extensor carpi radialis muscles and long heads of the triceps brachii muscles of 7 horses maintained under halothane anesthesia during controlled ventilation. Horses were positioned in left lateral recumbency on a water bed for 4 hours. Using a crossover design, 6 of the 7 horses were subjected to normotensive and hypotensive anesthesia on separate occasions. Hypotension was achieved by increasing the inspired halothane concentration. Hematologic and biochemical measurements were determined at designated intervals before, during and for 7 days after each anesthetic episode. Under hypotensive conditions, 2 horses developed severe, generalized myositis and were euthanatized. Three of the 5 other horses developed swelling of the downside masseter muscle, 4 demonstrated mild extensor deficits of the downside forelimb, and 1 had a severe extensor deficit of the uppermost hind limb. As a group, the hypotensive horses had markedly increased activities of serum enzymes (creatine kinase, aspartate transaminase, and blood lactate) and abnormalities in calcium-phosphorus homeostasis. Lameness or enzyme alterations were not observed in normotensive horses. Altough the intracompartmental pressure values were markedly increased in the muscle bellies of the compressed limbs of all horses, there was a statistically significant difference in intracompartmental pressures between the downside or compressed muscle compartments of the extensor carpi radialis of hypotensive and normotensive horses. High concentrations of halothane may predispose anesthetized horses to postanesthetic myositis, even when protective padding is used. Intracompartmental muscle pressure, as measured by the wick catheter, may not be a reliable predictor of equine postanesthetic lameness.

We tested the hypothesis that lymphocytes from swine with susceptibility to malignant hyperthermia (MH) had increased sensitivity to the membrane-perturbing effects of halothane that increase cytoplasmic calcium. Cytoplasmic concentration of ionized calcium in lymphocytes isolated from blood was determined in the presence and absence of halothane for 10 Pietrain X Poland China swine that were susceptible to MH and 20 Yorkshire swine that were resistant to MH. Calcium was determined by dual-emission spectrofluorometry and by measuring the ratio of free to calcium-bound form of the fluorescent calcium dye Indo-1. Mean values for calcium concentrations in lymphocytes from MH-susceptible (MHS) swine were 80% less than control values (40.5 +/- 38.8 and 185.3 +/- 91.6 nmol/L; P less than 0.01). Untreated lymphocytes from MHS swine accumulated calcium at half the rate observed for controls. Exposure to 1 mmol/L halothane resulted in a 3-fold increase of free calcium concentration to 127.9 +/- 81.9 nmol/L in the lymphocytes of MHS swine, but had no significant effect on lymphocytes from control swine (225.0 +/- 91.4; P less than 0.01). Exposure to 2 mmol/L halothane resulted in a 6-fold increase of free calcium concentration to 255.9 +/- 91.4 nmol/L in lymphocytes from MHS swine and a 63% increase in lymphocytes from controls (303.8 +/- 116). The rate of halothane-induced increase in cytosolic calcium was 13 times greater in lymphocytes from MHS swine, compared with controls. These data indicated that the molecular defect that results in halothane-hypersensitivity and is characteristic of muscle of MHS swine also occurs in lymphocytes from MHS swine.

A 4% pilocarpine gel applied topically to eyes was evaluated in glaucomatous Beagles and normotensive Miniature Schnauzers to determine its efficacy in reducing intraocular pressure (IOP) and to assess any side effects. Pilocarpine gel significantly (P less than 0.05) reduced IOP for 24 hours after treatment, compared with baseline (pre-drug) values, untreated fellow eyes, and placebo-treated eyes. The IOP remained significantly lower (P less than 0.05) during 3 treatment days, as well as the first 2 days after treatment. The pupil sizes were significantly smaller (P less than 0.01) in all treated dogs after the first administration of pilocarpine, compared with baseline values, untreated eyes, and placebo-treated eyes. The subsequent pilocarpine gel administrations induced significant miosis (P less than 0.01), compared with baseline values, but the extent of miosis and duration were significantly less (P less than 0.01) as the number of treatments increased. Conjunctival irritation and blepharospasm were observed mainly in the first 2 days of treatment and were minimal after subsequent applications. There was no contralateral effect on IOP or pupil size, compared with baseline values and placebo-treated eyes.

The relationships of various iron-related analytes were evaluated in 95 dogs. Liver and spleen nonheme iron content was determined coulometrically on acid-digested tissue specimens. Serum iron concentration and total iron-binding capacity also were measured coulometrically, whereas serum ferritin concentration was measured by ELISA. Significant (P less than 0.0002) correlation was found between serum ferritin concentration and nonheme iron stores. Significant correlation was not found between nonheme iron stores and serum iron concentration or total iron-binding capacity. Serum ferritin concentration should provide a convenient and relatively noninvasive means of estimating iron stores in dogs.