Immunocytochemical analysis of equine synovial membranes revealed presence of several neuropeptides, including substance P (SP), neurokinin A, and neuropeptide Y, in nerves of the radiocarpal, middle carpal, and metacarpophalangeal (fetlock) joints. Within the subsynovium, these neuropeptides were located perivascularly, whereas in the fronds, only neuropeptide Y was restricted to the vessels of the synovial membrane. Only SP and neurokinin A were found in the intimal layer. The intimal layer of the metacarpophalangeal joint contained more SP-immunoreactive fibers than were observed in the intimal layer of the radiocarpal joint. Substance P also was detected in the synovial fluid from all 3 joints, but mean +/- SD concentrations were significantly different only between the middle carpal joint (37.56 +/- 5.48 fmol/ml; n = 6) and the metacarpophalangeal joint (55.80 +/- 8.33 fmol/ml; n = 5) and between the middle carpal joint and the radiocarpal joint (52.43 +/- 14.60 fmol/ml; n = 7).

Intestinal permeability was assessed in 12 healthy cats by use of a differential sugar absorption test. A 50-ml isotonic aqueous solution containing a combination of 1.8 g of the disaccharide lactulose and 1.7 g of the monosaccharide mannitol was administered to cats via nasogastric tube. Urine was collected after 6 hours, and all urine samples were analyzed the same day, using a gas-liquid chromatographic technique (GLC) and an enzymatic assay (ENZ). Median urinary recovery of lactulose was 0.27 and 0.54% determined by GLC and ENZ, respectively. Differences between these groups were statistically significant (P = 0.023), and correlation between assays was high (r = 0.94, P < 0.01). Median urinary recovery of mannitol was 1.93 and 2.09% for GLC and ENZ, respectively. There were no statistically significant differences between these groups and the correlation between assays was high (r = 0.85, P < 0.01). The median lactulose-to-mannitol ratio was 0.29, using GLC, and was 0.52, using ENZ. Correlation of these ratios was again high (r = 0.93, P < 0.01).

Urethral pressures profiles (UPP) obtained by use of microtransducer catheters were determined in 8 anestrous sexually intact female Beagles during general anesthesia. A UPP study consisted of 3 consecutive recordings, and 4 UPP studies were repeated at an interval of 5 days in each dog. Maximal urethral pressure (cm of H2O), bladder pressure (cm of H2O), and anatomic urethral length (cm) were recorded. Maximal urethral closure pressure (cm of H2O) was calculated. Mean +/- SD (for all measurements) maximal urethral closure pressure was 12.8 +/- 5.6 cm of H2O (range, 2.4 to 25.2 cm of H2O). Maximal urethral closure pressure was significantly (P < 0.05) decreased during the first recording period (11.4 +/- 5.8 cm of H2O), Compared with the second (13.0 +/- 5.2 cm of H2O) or third 14.1 +/- 5.7 cm of H2O) recording periods within a UPP study (3 consecutive recordings). Mean maximal difference in urethral closure pressure during a single UPP study was 4.8 +/- 2.4 cm of H2O. Significant difference in maximal urethral closure pressure was not observed between studies. Mean (for all measurements) anatomic urethral length was 6.2 +/- 0.9 cm (4.1 to 7.8 cm). Anatomic urethral length was significantly (P < 0.05) less during the first recording period (6.1 +/- 0.9 cm), compared with values for the second and third periods (6.3 +/- 0.9 cm, 6.4 0.9 cm respectively). Anatomic urethral length for time 3 was significantly (P < 0.05) less than the value for time 1 (5.8 +/- 0.7 cm vs 6.6 +/- 0.8 cm). We conclude that the microtransducer catheter technique for measurement of UPP was reproducible during a single study and between successive studies. This method is useful in documenting maximal urethral pressure, maximal urethral closure pressure, and anatomic urethral length in clinically normal sexually intact female dogs.

Twenty newborn Holstein calves were allotted at random to 4 groups: group A received 0.9% sterile saline solution; group B received phenylbutazone (5 mg/kg of body weight, IV) and 0.9% sterile saline solution; group C received progressively increasing doses of endotoxin (0.1 to 15 micrograms/kg); and group D received phenylbutazone and endotoxin similarly as did calves of groups B and C, respectively. Phenylbutazone was given once daily and saline solution or endotoxin were given every 8 hours for 5 days. Clinical variables-PCV, plasma total protein and fibrinogen concentrations, platelet count, prothrombin time, activated partial thromboplastin time, and fibrin degradation products concentration were measured at 24-hour intervals. Necropsy was performed on each calf. Phenylbutazone suppressed the clinical response to endotoxin challenge until large doses (7.5 to 15 micrograms/kg) were administered. Calves of groups C and D remained stable until they abruptly developed severe dyspnea necessitating euthanasia. Thrombocytopenia and leukopenia developed after the initial endotoxin dose. Prothrombin time was prolonged and PCV suddenly decreased at 96 hours. Necropsy revealed consistent lesions in the vascular endothelium and lungs. Phenylbutazone administration did not enhance or ameliorate endotoxin-induced hemostatic alterations or pathologic lesions.

Efficacy of albendazole for treating giardiasis in dogs was assessed in 3 experiments. In experiment 1, Giardia cysts were cleared from feces of 5 of 7 dogs (as determined by the zinc-sulfate concentration technique) after the dogs received a single dose of albendazole (25 mg/kg of body weight, PO), whereas feces of 3 of 7 dogs became clear of cysts without treatment. In experiment 2, feces of 5 of 5 dogs became clear of cysts after albendazole treatment (25 mg/kg, PO, q 12 h for 4 doses); feces of 1 of 5 untreated control dogs became clear. In experiment 3, feces of 18 of 20 dogs became clear of cysts after albendazole 25 mg/kg, PO, q 12 h for 4 doses) was given; none of the 20 control dogs had feces clear of cysts. Signs of toxicosis were not observed in any dog. These results indicate that a single dose of albendazole (25 mg/kg, PO) is not effective for treating giardiasis in dogs. However, 4 doses of albendazole (25 mg/kg, PO, q 12 h) are highly effective and nontoxic for treatment of giardiasis in dogs.

Estradiol was administered to 3 steers (0.12 mg/kg of body weight/d for 14 consecutive days), followed by 2 days of nonfeeding (starvation). During estradiol administration, liver nuclear estrogen receptor and serum apolipoprotein B-100 (apoB-100), as well as serum triglycerides concentrations were increased, compared with values before administration. Starvation, together with interruption of estradiol administration, resulted in rapid decreases of the receptor, serum apoB-100, and serum triglycerides concentrations, and increase of nonesterified fatty acids concentration. Of the 3 steers, 2 had higher liver triglyceride content, compared with values before treatment. In the control group (3 steers that received vehicle alone, then starved similarly), these concentrations, except for serum nonesterified fatty acids and triglycerides concentrations after starvation, were not changed. In another experiment, serum apoB-100 concentration in dairy cows was significantly (P < 0.05) lower at parturition than values before and after parturition. These results indicate that estradiol may be involved in development of fatty liver in cattle.

The objectives of this experiment were to determine serum concentrations of triiodothyronine (T3), thyroxine (T4), and free thyroxine (fT4) at rest, following thyroid-stimulating hormone (TSH) administration, and following phenylbutazone administration in healthy horses. This was done to determine which available laboratory test can best be used for diagnosis of hypothyroid conditions in horses. Serum T3, T4, and fT4 concentrations in serum samples obtained before and after TSH stimulation and following phenylbutazone administration for 7 days were determined. Baseline values ranged from 0.21 to 0.80 ng of T3/ml, 6.2 to 25.1 ng of T4/ml, and 0.07 to 0.47 ng of fT3/dl. After 5 IU of TSH was administered IV, serum T3 values increased to 6 times baseline values in 2 hours. Thyroxine values increased to 3 times baseline values at 4 hours and remained high at 6 hours. Free T4 values increased to 4 times baseline values at 4 hours and remained high at 6 hours. Administration of 4.4 mg of phenylbutazone/kg, every 12 hours for 7 days significantly decreased T4 and fT4 values, but did not significantly affect serum T3 concentrations, It was concluded that a TSH stimulation test should be performed when hypothyroidism is suspected. Measurement of serum fT4 concentrations, by the single-stage radioimmunoassay, does not provide any additional information about thyroid gland function over that gained by measuring T4 concentrations. Phenylbutazone given at a dosage of 4.4 mg/kg every 24 hours, for 7 days did significantly decrease resting T4 and fT4 concentrations, but did not significantly affect T3 concentrations in horses.

Dexamethasone pharmacokinetics was studied in 10 healthy dogs receiving high-dose administration of dexamethasone (dosage, 0.1 mg/kg of body weight, IV), alone or combined with ACTH dosage, 0.5 U/kg, IV), or low-dose administration of dexamethasone (dosage, 0.01 mg/kg, IV) in an incomplete cross-over design. Serum samples were obtained at 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, 720, 1,080, 1,440, 1,920, 2,400, and 2,880 minutes after dexamethasone administration; dexamethasone was measured by radioimmunoassay validated for use in dogs. Dexamethasone pharmacokinetics was adequately described by a two-compartment first-order open model. Comparison of pharmacokinetics for the low- and high-dose protocols revealed dose dependence; area under the curve, mean residence time, clearance, and volume of distribution increased significantly when dexamethasone dosage increased, The elimination rate constant was significantly (P < 0.05) less, and the elimination half-life significantly greater for the high-dose protocols; however, the distribution rate constant and distribution half-life were not significantly different when high-dose protocols were compared with the low-dose protocol. Dose-dependent increases in volume of distribution and clearance may be related to saturation of protein-binding sites. Concurrent administration of ACTH did not affect dexamethasone disposition.

Paired CSF and serum samples were obtained from 109 rhesus macaques aged 1 to 18 years. The CSF and serum IgG and albumin concentrations were determined, using radial immunodiffusion; CSF total protein and glucose were determined, using colorimetric methods; and Na, K, and Cl concentrations were determined, using ion-specific electrodes. The CSF protein values were lower than those reported for nonhuman primates, and this finding was confirmed by results of agar gel electrophoresis. Animal age and sex had no significant effects on CSF composition, but serum IgG concentration increased with age. Concentrations of total protein, albumin, and IgG were greater, and concentrations of glucose and potassium were lower in CSF obtained from the lumbar rather than the cisternal site. Composition of CSF was not significantly altered by contamination with blood at values up to 10,000 RBC/microliter. The CSF albumin quotient, IgG quotient, and IgG index were determined and differed markedly from values reported for human beings, indicating that the properties and specificity of the blood-brain barrier may be species-specific.

Cows and calves from a 1,600-cow drylot dairy were screened for IgG antibodies to Salmonella dublin lipopolysaccharide (LPS), using an indirect ELISA. The ELISA was performed on milk samples from lactating cows and on sera from nonlactating cows and calves. Fecal samples were collected from calves and nonlactating cows for culture of Salmonella spp. All seropositive cattle were retested by culture and ELISA 5 times at monthly intervals or until antibody concentration decreased. None of the cattle remained culture-positive and seronegative. Prior to and during the sample collection period, approximately 30% of calves < 8 weeks old died of S dublin infection. Vaccination of cows with a killed S dublin/S typhimurium vaccine at cessation of lactation was a routine management practice. The ELISA-determined Igg response to vaccination had decreased by 50 days after vaccination. Eight cows and 5 calves that maintained a high serologic response to S dublin were purchased and moved to a research facility for 6 months of intensive monitoring. Lactating cows were milked twice daily, and culture of milk and feces for Salmonella spp was performed 5 times/wk. Serum IgG antibodies to S dublin LPS were measured weekly, using ELISA. At the end of 6 months, all 13 cattle were necropsied and tissues were obtained for culture of Salmonella spp. All 8 cows and 5 calves maintained persistently high ELISA titer for the 6 months of testing, and shed S dublin in the milk and/or feces during the same period. On this basis, they were termed S dublin carriers. Salmonella dublin was isolated from mammary tissue of 2 calves at necropsy, indicating that bacteremia may be a mode of mammary infection by S dublin. Results of the study indicated serologic testing can be used successfully on a large dairy to identify S dublin carrier cattle. Using initial milk screening, 42 of 1,268 lactating cows were identified as suspect, requiring repeated serologic testing. One nonlactating cow, 7 of the 42 suspect lactating cows, and 5 of the 222 calves maintained an Igg response, and were found to be S dublin carriers. Carrier cows shed S dublin in 3.35% of fecal samples and 2.51% of milk samples, and carrier calves shed S dublin in 17.26% of fecal samples.