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.

Plasma concentration of immunoreactive atrial natriuretic peptide (ir-ANP) was investigated in 83 Cavalier King Charles Spaniels with variable severity of mitral regurgitation caused by chronic valvular disease (CVD). Severity of mitral incompetence was assessed by echocardiography. Significant differences in plasma concentrations of ir-ANP were not found between clinically normal dogs (New York Heart Association functional class O), dogs with only cardiac murmur (class I), and dogs with echocardiographic evidence of slight to moderate left atrial and ventricular dilatation (class II). Dogs with severe left atrial and ventricular dilatation and clinical signs of congestion (classes III and IV) were found to have significantly (P < 0.001) increased plasma concentration of ir-ANP. Overall, moderate degree of association was found between plasma concentration of ir-ANP and left atrial and left ventricular diameters (Pearson's r = 0.65, 0.60, respectively, P < 0.001), as well as heart rate (r = 0.47, P < 0.01). However, left atrial enlargement as found to have the predominant effect on plasma ir-ANP concentration. It is concluded that the plasma concentration of ir-ANP did not become markedly increased before decompensation of chronic mitral regurgitation associated with severe enlargement of the left atrium and ventricle in Cavalier King Charles Spaniels.

Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (MSD) values and application of the established MSD values for diagnosis of cervical stenotic myelopathy (CSM). Variability in MSD determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The MSD of the vertebral canal was determined in 50 horses with CSM and 50 control horses, using a radiopaque marker method for correction of magnification. In addition, a ratio of the absolute MSD to the sagittal width of the vertebral body and a ratio of the absolute MSD to the length of the vertebral body were determined in 100 CSM-affected and 100 control horses. Response operating characteristic curve analysis of each method determined that the sagittal ratio method of canal diameter assessment provided the most accurate interpretation of cervical radiographs for diagnosis of CSM, with sensitivity and specificity of larger than or equal to 89% at each vertebral site. The accuracy of the ratio method, without consideration of bony malformation, supports the importance, and perhaps prerequisite, of generalized vertebral canal stenosis in the pathogenesis of CSM. Subjective evaluation of bony malformations from cervical radiographs of 100 CSM-affected horses and 100 control horses indicated that CSM-affected horses have more severe bony malformation than do control horses. However, moderate to marked degenerative joint disease of the articular processes was frequently observed in control horses. Subjective evaluation of bony malformation does not distinguish between CSM-affected and unaffected horses.

Temporal changes, as well as differences in distribution, in concentrations of 24 amino acids in plasma and whole blood of neonatal foals were determined from birth to 2 days of age. In addition, differences in concentrations of amino acids in plasma between mare and foal pairs were determined at birth. Significant (P < 0.05) hypoaminoacidemia existed for 15 amino acids in plasma of foals at birth, compared with mares (paired t-test). Concentrations of 7 amino acids (aspartate, glutamate, glutamine, glycine, hydroxyproline, phenylalanine, proline) in plasma of foals were higher (P < 0.05) at birth than in mares, and concentrations of 2 (taurine, tryptophan) were not different (P > 0.05). Significant (P < 0.05) temporal changes for concentrations of 19 of 24 amino acids in plasma were observed during the 48-hour period. Concentrations of 13 of the 19 amino acids in plasma that had significant changes were higher (P < 0.05) at 48 hours. Significant (P > 0.05) effect of time on concentration of 5 amino acids (alanine, methionine, phenylalanine, taurine, threonine) in plasma was not found after birth. Temporal changes in concentrations of 7 amino acids (alanine, asparagine, glutamine, histidine, hydroxyproline, methionine, and threonine) in whole blood were not significantly (P > 0.05) different from those in plasma. Temporal changes for concentrations of the remaining 17 amino acids in whole blood were significantly (P < 0.05) different, compared with plasma. Distribution of the concentrations of 18 amino acids between whole blood and plasma was significantly (P < 0.05) different. Concentrations of 5 amino acids (citrulline, cystine, glutamine, methionine, tryptophan) were significantly (P < 0.05) lower in whole blood than in plasma, whereas concentrations of 13 amino acids were significantly (P < 0.05) higher in whole blood vs plasma. Concentrations of 6 amino acids (asparagine, isoleucine, leucine, proline, serine, valine) in whole blood were not significantly different from concentrations in plasma. Significant differences in temporal patterns of concentrations of amino acids in plasma and whole blood may be attributable to nutritional or physiologic changes associated with parturition. Significant differences between concentrations of amino acids in whole blood and plasma may be attributable to ontogeny or specificity of transport systems across cell membranes.

A former secondary lead smelter was in operation in Granite City, Ill, until the early 1980s. As a result, the surrounding area is heavily contaminated with lead. Soil concentrations as high as 5,000 ppm have been measured in prior studies. Because of growing concerns about health defects associated with low levels of lead exposure in human beings, a major study has been conducted on people living in the area. The study reported here was a corollary to the human exposure study. Lead concentration was determined in 84 dogs and 26 cats in the town and ranged between < 5 and 28 microgram/dl. None of the dogs had clinical signs of lead poisoning. The CBC and serum biochemical values did not indicate many significant differences between dogs with a high (larger than or equal to 10 microgram/dl) or low blood lead concentration (BLC). Hemoglobin concentrations were lower, and WBC counts were higher in dogs and cats with higher BLC, but they were still within reference ranges. Free erythrocyte protoporphyrin concentration was determined. Normal values appeared to be similar for dogs and cats. Only animals with BLC larger than or equal to 20 microgram/dl were found to have somewhat increased concentration of free erythrocyte protoporphyrin. Delta-aminolevulinic acid dehydratase activity was measured and found to be negatively correlated with BLC. The relation was strong, even at low BLC (5 to 10 microgram/dl) in both species. Age or sex difference was not observed. Therefore, biological changes associated with low BLC were limited to BLC in the 10- to 30-microgram/dl range.

A solid-phase ELISA to detect antibodies bound to the surface of canine platelets (platelet-bound antibodies) is described. Using this assay, the effect of anticoagulant and storage time of anticoagulant blood on the concentration of antibodies bound to the surface of platelets from clinically normal dogs was investigated. Blood from 3 clinically normal dogs was anticoagulated with acid citrate dextrose, Na3 citrate, and aqueous K3 EDTA and stored on ice for up to 48 hours. Platelet-bound antibody concentration was measured on platelets isolated from anticoagulated blood immediately after venipuncture and subsequent to storage of blood for 24 and 48 hours. Differences in platelet-bound antibody concentrations were investigated among dogs, anticoagulants, and storage times by ANOVA and Bonferroni pair-wise comparison of means. There was no effect of dog on platelet-bound antibody concentration. The effect of time was significant (P < 0.0001), with higher concentration of platelet-bound antibodies detected with increasing storage time. Effect of anticoagulant on platelet-bound antibody concentration was not statistically significant; however, there was a trend to increasing concentration of antibodies bound to platelets isolated from Na3 citrate- and K3 EDTA-anticoagulated blood. Moreover, there was significant (P = 0.02) interaction between anticoagulant and time. Platelet-bound antibody concentration increased with storage of anticoagulated blood prior to platelet isolation and with use of Na3 citrate and K3 EDTA anticoagulants. The preferred anticoagulant for platelet-bound antibody measurement is acid citrate dextrose. Platelet-bound antibody concentration should be determined not longer than 24 hours after blood collection.

The usefulness of tidal breathing flow-volume loops (TBFVL) to evaluate pulmonary function was investigated in 6 Standardbreds during treadmill exercise. Tidal breathing flow-volume loops are a graphic representation of airflow rate vs tidal volume for each individual breath. These TBFVL were obtained from horses exercising it speeds corresponding to 75 and 100% of maximum heart rate. Measurements were recorded in each horse before and after ovalbumininduced allergic lung disease. Moderate obstructive lung disease, characterized by a significant increase in pulmonary resistance, was observed while the horses were at rest. We found that in horses with airway obstruction exercising at 75 or 100% of maximum heart rate, the quantitative indices describing TBFVL shape and size were not markedly different from those in clinically normal horses exercising at similar speeds.

Schirmer tear test (STT), intraocular pressure (IOP) measurement, slit-lamp biomicroscopy, and indirect ophthalmoscopy were performed on 8 dogs with (13)l-induced hypothyroidism and 4 euthyroid control dogs at weeks 0, 9, 13, 17, immediately prior to treatment with levothyroxine, after 5 weeks of levothyroxine administration (0.022 mg/kg of body weight, PO, q 12 h), and at euthanasia 7 weeks after discontinuation of replacement therapy. Although the control group had higher baseline STT values than the hypothyroid group after randomization of dogs into the 2 groups (P < 0.01), STT values remained unchanged from their respective baseline values at all time intervals for both groups. Hypothyroid and control dogs had significant (P < 0.05) reduction in IOP from baseline values at all subsequent time points, but differences were not observed when hypothroid dogs were compared with controls. Goblet cell indices determined from biopsy samples of the inferior-nasal conjunctival fornix obtained before induction of hypothyroidism (baseline), immediately prior to and at conclusion of levothyroxine therapy, and at euthanasia were not significantly different when values for hypothyroid dogs were compared with their own baseline values or with values for control dogs. Histologic examination of the globes and adnexa at euthanasia also failed to indicate consistent qualitative differences between hypothyroid and control dogs. Marked reduction in serum thyroid hormone concentrations had little effect on the eye and ocular adnexa over the course of the study.

An ELISA, using purified flagellin of Borrelia burgdorferi as the solid-phase antigen, was used to measure antibody concentrations to B burgdorferi in dairy cattle in Wisconsin. Serum obtained from 5,060 cows in 160 randomly selected herds in the state were tested. Serum from an additional 2,600 cattle in Barron County, Wis, a county with a high annual incidence of B burgdorferi infections in human beings, was also tested. Only 7% of the cows that were tested, but 66% of the herds that were tested, were seropositive for B burgdorferi. Sixteen percent of the herds had a prevalence of 15% seropositive cows, whereas 50% of the herds had a prevalence of 1 to 14% seropositive cows. Seropositive herds were concentrated in the west-central part of Wisconsin. An association existed between the geographic location of seropositive herds and counties in which B burgdorferi infection of human beings was acquired (P < 0.05) as well as the geographic location of seropositive herds and the geographic distribution of Ixodes scapularis (P < 0.05). Barron County, in which B burgdorferi infection is endemic, had a significantly (P < 0.05) higher percentage of seropositive cows (17%) than did the state of Wisconsin (7%).

Equine endometria representative of Kenney's categories I, II, and III were incubated in vitro with phosphate buffer, Streptococcus pneumoniae, or S zooepidemicus. Endometrial tissues from mares in estrus and diestrus were first categorized according to Kenney's classification, then were tested for adherence of S pneumoniae and S zooepidemicus to the epithelia. Bacteria were not observed when the endometrial tissue was incubated with phosphate buffer or S pneumoniae. There was no statistical difference in attachment of S zooepidemicus to endometrial tissue from mares in estrus or diestrus if endometrial classification was ignored. However, bacterial attachment was significantly (P less than or equal to 0.05) higher in category III endometrium during estrus.