Effects of age and prosthesis material on in vitro cartilage retention of laryngoplasty prostheses in horses

Cartilage retention strengths of laryngoplasty prostheses were compared in larynges of 2-, 3-, and 4-year-old horses, using doubled polyester and expanded polytetrafluoroethylene prostheses. Bilateral laryngoplasties were performed on each of 15 (seven 2-year-old, two 3-year-old, and six 4-year-old) larynges, which were collected at an abbatoir. Prostheses were secured to a mechanical testing machine, and tension causing arytenoid cartilage abduction was applied, until total failure of the cartilage or prosthesis resulted. Tension caused cricoid cartilage failure in 1 specimen, and muscular process cartilage failure in the remainder. There was no significant effect of age, prosthetic material, or side of prosthesis placement on cartilage retention of the prostheses. Additionally, frequency of multiple load-displacement peaks, indicating partial muscular process failure, was not affected by age or prosthetic material variables.     

Characterization of a panel of monoclonal antibodies and their use in the study of the antigenic diversity of bovine viral diarrhea virus

A panel of 40 monoclonal antibodies (MAb) specific for bovine viral diarrhea virus (BVDV) was produced, and each MAb was characterized and grouped according to its viral protein specificity, immunoglobulin subclass, virus-neutralizing activity, and immunoreactivity with a large collection of BVDV isolates. The MAb were found to be specific for 1 of 3 sets of related viral-induced proteins found in cells infected with the Singer strain of BVDV. Group-1 MAb were specific for the 80- and 118-kilodalton (kD) proteins of BVDV. Group-2 MAb recognized 3 proteins with molecular sizes of 54, 56, and 58 kD. Group-3 MAb recognized a 43- and a 65-kD protein. The MAb belonged to either the IgG1, IgG2a, IgG2b, IgG3 subclasses or the IgE class of mouse immunoglobulin. All MAb in group 2 were able to neutralize BVDV and had neutralization titers that ranged from 24 to 1,600,000. The reactivity of the MAb with numerous field isolates of BVDV was highly variable. Both cytopathic and noncytopathic biotypes of BVDV were examined and had the same degree of antigenic variation. The greatest degree of variation was detected with group-2 MAb. The data demonstrate that BVDV isolates have a high degree of antigenic variation that is largely confined to the envelope glycoproteins associated with virus neutralization. The results also suggest that antigenic variability of this virus is important in the development and severity of the disease it causes.     

Strength Characteristics and Failure Modes of Locking-Loop and Three-Loop Pulley Suture Patterns in Equine Tendons

Size 3-0 polydioxanone was used as a single strand, single braid (3 strands), or double braid (6 strands) to create six suture material-pattern combinations for equine tenorrhaphy: single-strand locking loop, single-braid locking loop, double-braid locking loop, single-strand three-loop pulley, single-braid three-loop pulley, and double-braid three-loop pulley. Maximum load to failure for the single-strand locking loop (46.1 +/- 2.9 newtons [N]) was less than for all other sutures (range, 103-155 N). The load required to form a 2 mm gap between tendon ends was greater for the single-braid three-loop pulley (66.7 +/- 6.9 N) and double-braid three-loop pulley (85.4 +/- 17.7 N) than any other sutures. The load required to produce a 10 mm gap was least for the single-strand locking loop (34.3 +/- 3.9 N) and greatest for the double-braid three-loop pulley (131.5 +/- 27.5 N). Gap between tendon ends at maximum load was greater for the single-braid (18.1 +/- 0.9 mm) and double-braid (19.2 +/- 2.2 mm) locking loops than for any other sutures. Suture material broke in 53% of the locking-loop tests but in only 17% of the three-loop pulley tests. Tendon matrix disruption accounted for 43% of the locking-loop failures and 77% of the three-loop pulley failures. The three-loop pulley pattern provided more support, less tendon distraction, and less tendon matrix constriction and distortion than the locking-loop pattern.(ABSTRACT TRUNCATED AT 250 WORDS)     

Safety and efficacy of two sustained-release intrareticular selenium supplements and the associated placental and colostral transfer of selenium in beef cattle

One hundred fifty Se-deficient, pregnant, crossbred beef cows were assigned to 1 of 4 treatment groups: group A, Se-deficient control; group B, 1 Se bolus at 0 and 119 days; group C, 1 Se bolus at 0 days; and group D, 2 Se pellets at 0 days. The Se bolus is an osmotic pump designed to release 3 mg of Se/d into the reticulorumen. The Se pellets weight approximately 30 g and contain 10% elemental Se, which is liberated in the reticulorumen. The Se bolus is designed to provide Se supplementation for 120 days and the Se pellets provide supplementation for up to 18 months. Cattle were maintained on Se-deficient pasture or forages prepared from these pastures for the duration of the experiment. Blood samples were collected from cows prior to treatment (time 0) and at 28, 52, 119, and 220 days thereafter and analyzed for blood Se (BSe) concentration. Body weights were recorded at each sampling time. Blood Se concentration of cows from all supplemented groups were significantly (P less than 0.01) higher than control values at all sample dates after treatments began. By the end of the 220-day study, treatment group-B cattle had significantly (P less than 0.01) higher BSe concentrations than any other group. Body weights of treatment groups fluctuated throughout the study, but did not differ (P greater than 0.05) between groups. One cow and 6 calves born to cows during the experimental period died. Necropsy of 5 calves provided no evidence linking these deaths to treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of isoenergetic infusions of propionate and glucose on portal-drained visceral nutrient flux and concentrations of hormones in lambs maintained by total intragastric infusion

Three lambs were used in a repeated Latin square design to determine the influence of isoenergetic infusions of propionate or glucose on portal-drained visceral flux (PDV) of nutrients and concentrations of insulin, glucagon, growth hormone and prolactin. Lambs were fitted with appropriate catheters for blood sampling and maintained on total intragastric infusion of nutrients. Basal VFA, casein, mineral and vitamin infusions (isocaloric and isonitrogenous) were supplemented with an additional 22 +/- .5 kcal/h from propionate, glucose or a combination of propionate plus glucose. Ruminal fluid proportion and arterial blood concentration and PDV flux of propionate increased (P less than .10) by 17 mol/100 mol, .02 mM and 40 mmol/h, respectively, with infusion of an additional 61 mmol/h of propionate. Regression equations predicted that, on a net basis, 67% of ruminally infused propionate and 43% of abomasally infused glucose appeared in portal blood. Arterial L-lactate, beta-hydroxybutyrate and acetate concentrations, and beta-hydroxybutyrate flux were increased (P less than .10) by .34 mM, .20 mM, .50 mM and 4.2 mmol/h, respectively, with infusion of 33 mmol/h of added glucose. Net utilization of glucose by the PDV was approximately 4.4 mmol/h when no glucose was infused. Increased infusion of propionate resulted in a 22.2-micrograms/h increase in PDV flux of insulin (P less than .08) but had no effect on arterial insulin, glucagon and prolactin concentrations (P greater than .10). Arterial growth hormone increased by 3.8 ng/ml with increasing glucose infusion (P less than .08).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of biochemical evidence of congenital nutritional myopathy in two-week prepartum fetuses from selenium-deficient ewes

Muscle damage attributable to selenium (Se)/vitamin E deficiencies is known to develop at birth or later in lambs. The purpose of this study was to determine whether and when muscle damage develops in utero. Thirty pregnant ewes maintained on Se-deficient forages from birth were allotted to 3 equal groups. Half of each group was given a single IM injection of 0.056 mg of Se/kg of body weight, 1 month before parturition. At 3 weeks before parturition, cesarean section-derived fetuses from Se-deficient ewes did not have evidence of muscle damage. At 2 weeks before parturition, fetuses from Se-deficient ewes had biochemical evidence of congenital nutritional myopathy, as evidenced by low blood Se concentration (P less than 0.05) and by increased plasma creatinine kinase (P less than 0.001) and lactate dehydrogenase (P less than 0.01) activities, compared with fetuses from Se-treated ewes. Thus, for optimal protection of fetuses and newborn lambs in Se-deficient areas, Se should be administered to ewes at least 1 month before parturition.     

Infarction of the pons and medulla oblongata caused by arteriolar thrombosis in a horse

Infarction of the pons and rostral medulla secondary to arteriolar thrombosis was documented histologically in a 17-year-old mixed-Arabian female horse. Clinically, the animal experienced a sudden onset of a head tilt and subsequent non-controllable seizures. There was no historical, clinical or histological evidence to suggest the presence of infection of Equine Herpesvirus-1 or the feeding of corn contaminated by Fusarium moniliforme.