Pharmacokinetic variables of skeletal muscle creatine kinase (CK) activity after IV administration of a muscle extract; CK bioavailability after IM administration of the muscle extract; and effect of IM administration of saline solution, to appreciate the possible release of CK consecutive to muscle puncture, were determined in 6 cows. A general equation for the quantitative estimation of skeletal muscle damage also was derived. Administration of saline solution IM had no effect on plasma CK activity (ANOVA, P > 0.05) in any of the cows. After IV administration of the muscle extract (150 U/kg of body weight), mean volume of the central compartment, plasma half-life, and plasma clearance of CK were 0.027 +/- 0.007 L/kg, 520 +/- 109 minutes, and 6.43 +/- 2.29 ml/kg/h, respectively. After IM administration (150 U/kg), mean bioavailability of CK was 51 +/- 17% and maximal plasma CK activity (500 +/- 97 U/L) was observed at 454 +/- 131 minutes. The rate of CK activity entry into plasma was determined by use of deconvolution analysis. Two peaks were observed; the first appeared before the 30th minute after IM administration, and the second appeared at 3.3 +/- 1.1 hours. Amplitudes were 6.31 +/- 4.45 and 6.57 +/- 3.08 U/kg/h, for the first and the second peaks, respectively. The quantity of CK liberated from control muscle was 0.69 +/- 0.12 U/kg/h, corresponding to a normal daily catabolism of 5.8 +/- 1.0 mg of muscle/kg. From these results, the following equation can be proposed to determine the corresponding mean equivalent of destroyed muscle (Qmuscle, test article) after IM administration of a test article: Qmuscle, test article (g/kg) = 4.41 X 10(-6) AUC (U/h/L), with AUC being the CK plasma activity area under the curve.

During the hunting season of 1992, 322 black bears from Pennsylvania were examined for Toxoplasma gondii- and Trichinella spp-induced infections. Toxoplasma gondii antibodies were found in 79.8% of 322 bears--titer < 1:25 in 65 (20.2%), 1:25 in 18 (5.6%), 1:50 in 11 (34.5%) and 1:500 in 128 (38.7%) bears--by use of the modified agglutination test. Muscle tissues from 89 of these bears were bioassayed for T gondii parasites. Muscles from 64 bears, including heart from 1 bear, and heart alone from another bear, were digested in pepsin, and the digested samples were bioassayed in mice. Toxoplasma gondii was isolated from 5 bears; from the heart of 1, heart and skeletal muscles of 1, and skeletal muscles of 3. The T gondii antibody titers for the 5 bears with detectable T gondii were: greater than or equal to 1:25 in all 5 bears by use of the modified agglutination test; < 1:10 (3 bears, considered Toxoplasma-negative), 1:20 and 1:320 by use of the Sabin-Feldman dye test; < 1:64 (3 bears, considered Toxoplasma-negative), 1:128, 1:512 by use of the indirect hemagglutination test, and < 1:16 (2 bears, considered Toxoplasma-negative), 1:32, 1:64, and 1:512 by use of the latex agglutination test. Toxoplasma gondii was not isolated from feces of 5 cats fed muscles from the remaining 25 bears with T gondii antibody titer < 1:25. Tissue cysts of the 4 T gondii isolates from bears were rendered noninfective by freezing at -13 C. Antibodies against Trichinella spp were found in 6 (1.8%) of 319 bear sera; Trichinella spp larvae were detected in muscle digests of 2 of 63 bears, and in histologic sections of muscles from 3 of 162 bears. Genetic typing indicated that the 2 Trichinella isolates from bears were a sylvatic genotype and were not the species found in domestic pigs.

During growth, central venous, right ventricular, pulmonary arterial, Pulmonary capillary wedge, and systemic arterial pressures, heart rate, and cardiac Output were repeatedly measured in 41 Friesian calves, considered as having conventional muscular conformation, and in 19 Belgian White and Blue double-muscled calves. A total of 123 and 70 recordings were collected in conventional and double-muscled calves, respectively. These circulatory indices were calculated: stroke volume, cardiac and stroke indices, pulmonary and systemic pulse pressures, pulmonary and systemic vascular resistance indices, and right and left ventricular work indices. Results indicated that systemic arterial and pulse pressures, as well as cardiac output, stroke volume, cardiac and stroke indices, and right and left ventricular work indices were significantly (P less than or equal to 0.05 to 0.001) lower but, in contrast, pulmonary and systemic vascular resistance indices were significantly (P less than or equal to 0.001) higher in double-muscled than in conventional calves. Right-sided vascular pressures and heart rate were similar in the 2 groups. These results indicated that global cardiac performance may be considerably poorer in double-muscled calves. Diminished cardiac performance of double-muscled calves appears to be related neither to relative bradycardia nor to reduced ventricular preload. The potential role of increased ventricular afterload or of reduced myocardial contractility in double-muscled cattle should be determined by direct measurements.

Clinical, morphologic, and morphometric findings are reported in 14 young Dalmatians with laryngeal paralysis. Neurologic signs, including megaesophagus, were observed in 13 of 14 dogs. Electromyographic abnormalities included fibrillation potentials and positive sharp waves in laryngeal, esophageal, facial, and distal appendicular muscles. Neurogenic atrophy was detected in intrinsic laryngeal and appendicular skeletal muscles. A diffuse, generalized polyneuropathy, dominated by axonal degeneration, was observed in recurrent laryngeal and appendicular peripheral nerves. Results of quantitative studies, using single teased fiber and cross-sectional nerve preparations, indicated that changes were more severe in distal parts of peripheral nerves, with preferential loss of medium sized (5.5 to 8 micrometers) and large-caliber (8.5 to 12 micrometers) myelinated nerve fibers. Ultrastructural alterations were observed in myelinated and unmyelinated nerve fibers. The term laryngeal paralysis-polyneuropathy complex is proposed for this apparent dying-back disorder, which is clinically, electrophysiologically, and pathologically different from laryngeal paralysis in young Bouvier des Flandres and Siberian Huskies. Prognosis for Dalmatians with laryngeal paralysis-polyneuropathy complex is guarded to poor. The condition is believed to be inherited.