bluuebunny/crossref_metadata_2025 huggingface dataset:
Microsomal activation of constituents of white snakeroot (Eupatorium rugosum Houtt) to form toxic products
Authors: Beier Ross C. , Norman James O. , Irvin T. Rick , Witzel Donald A.
Published: February 2025

Components of white snakeroot, a plant toxic to livestock and human beings, were activated by Aroclor 1254-induced rat liver microsomes. The toxic products of microsomal activation were evaluated in murine melanoma (B16F1) cell cultures. Toxic products in white snakeroot were inactive in cell culture systems without microsomal activation. This activation system revealed that at least 2 fractions of white snakeroot were metabolically activated to cytotoxic agents. The autocatalytic inactivator of cytochrome P-450, 1-aminobenzotriazole, inhibited activation of white snakeroot constituents by rat liver microsomes.
Enzyme-linked immunosorbent assay for detection of Mycoplasma californicum-specific antibody in bovine serum: Optimization of assay determinants and control of serologic cross-reactions
Authors: Thomas C. B. , Jasper D. E. , Boothby J. T. , Dellinger J. D.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was adapted to detect Mycoplasma californicum-specific antibodies in bovine serum. Cross-reactive antibody was found in the M californicum-positive reference serum when assayed against each of 7 solid-phase antigens of heterologous mycoplasma species. Cross-reactivity was further demonstrated by inhibition of elisa reactivity to M californicum solid-phase antigen by incubation of sera with antigen suspensions of each heterologous species. Incubation of test sera with a cross-reacting antigen mixture containing equal proportions of the 7 cross-reactive mycoplasmas was used to minimize cross-reactivity in the M californicum-specific elisa. Specificity of antibody reactivity to M californicum, as measured by elisa, was determined by enzyme-linked immunosorbance inhibition, in which sera were incubated with M californicum antigen suspensions before determining elisa reactivity to M californicum solid-phase antigen. Seropositive and suspect sera (n = 55) were obtained from 3 dairies that had bacteriologically verified epizootics of M californicum mastitis. The percentage of inhibition demonstrated in enzyme-linked immunosorbance inhibition was determined for each serum. Inhibition percentages below the 15th percentile (61% inhibition) of this distribution were classified as nonspecific.
Rectal transmission of bovine leukemia virus in cattle and sheep
Authors: Henry Edward T. , Levine Jay F. , Coggins Leroy
Published: February 2025

Bovine leukemia virus (blv) was transmitted by rectal inoculation of blv-infective whole blood into cattle and sheep. Two cows and 2 sheep each were given 500 ml and 50 ml of blood, respectively, by rectal infusion. Two sheep which served as positive controls each were given 1 ml of the same blood, iv. All animals became seropositive to blv by postinoculation week 5. Although relatively large volumes of blood were used for rectal inoculation, a base line for infectivity was established for the rectal route.
Effect of yohimbine on xylazine-induced hypoinsulinemia and hyperglycemia in mares
Authors: Greene S. A. , Thurmon J. C. , Tranquilli W. J. , Benson G. J.
Published: February 2025

Serum insulin and plasma glucose concentrations were determined in 8 mares. Four iv treatments were studied: (i) xylazine (1.1 mg/kg of body weight); (ii) yohimbine (0.125 mg/kg); (iii) yohimbine (0.125 mg/kg) followed 5 minutes later by xylazine (1.1 mg/kg); and (iv) 5 ml of isotonic saline solution as a control. Blood samples were collected before (time 0) and at 5, 15, 30, 60, 120, and 180 minutes after drug administration. Serum insulin concentration decreased and plasma glucose concentration increased in mares given xylazine. Plasma glucose concentration was unchanged in control mares and in mares given yohimbine or yohimbine followed by xylazine. Serum insulin concentration was unchanged in mares given saline solution, but transiently increased in mares given yohimbine alone. Treatment with yohimbine prevented xylazine-induced hypoinsulinemia and hyperglycemia.
Pharmacokinetics of single doses of phenobarbital given intravenously and orally to dogs
Authors: Pedersoli W. M. , Wike J. S. , Ravis W. R.
Published: February 2025

Pharmacokinetics of phenobarbital was studied in 10 healthy dogs after single iv or oral administration. Phenobarbital sodium was administered iv to 5 dogs in group A (5.5 mg/kg of body weight) and 5 dogs in group B (15 mg/kg). Serial venous blood samples (n = 21) were collected from each dog before (base line) and after the administration of phenobarbital sodium for pharmacokinetic evaluation. After a 30-day resting period, 3 dogs in group A and 3 in group B were randomly selected and used for an iv crossover treatment. The iv treatment mean half-life of phenobarbital sodium was 92.6 ± 23.7 and 72.3 ± 15.5 hours, whereas mean total clearance was 5.60 ± 2.31 and 6.66 ± 0.78 ml/hr/kg for doses of 5 and 15 mg/kg, respectively. The mean residence time was 124 ± 34 hours and 106 ± 23 hours for the 5.5 and 15 mg/ kg, iv doses, respectively. Significant differences (P > 0.05) were not observed in pharmacokinetic parameters between the 2-dose study.

After a 35-day resting period, dogs in groups A and B were treated as described for the single iv treatment, except that they were given a phenobarbital tablet orally. Serial venous blood samples (n = 24) were collected before (base line) and after the administration of phenobarbital. Mean bioavailability was 88.1 ± 12.4% and 96.8 ± 9.0%, half life of absorption was 0.263 ± 0.185 and 0.353 ± 0.443 hour, and lag time was 0.611 ± 0.683 and 0.741 ± 0.554 hour for groups A and B, respectively. A significant difference (P > 0.05) was not measured for these values between groups A and B.
Antimicrobial alternatives for calf diarrhea: Sera trace element responses to Escherichia coli-, deferoxamine-, or gallium-induced diarrhea
Authors: Fettman Martin J. , Brooks Patricia A. , Phillips Robert W.
Published: February 2025

Aseptic and septic inflammatory diseases often are associated with marked changes in tissue and sera trace element kinetics. Iron and zinc sequestration by the host may serve as a protective effect against microbial proliferation, but may deprive host tissues of these necessary elements as well. Conversely, systemic iron administration has been shown to increase susceptibility to, and severity of, infectious diseases, although deficient iron stores may be repleted. Escherichia coli enteritis in calves provides a model wherein the effects of enteric iron antagonism and parenteral iron supplementation may be studied simultaneously. Male calves (n = 12) were given (im injection) 300 mg of iron-dextran after base-line blood samples were obtained, then the calves were allotted to 4 groups (each of 3 calves): group 1 (control)—orally given nonpathogenic E coli; group 2—orally given enterotoxigenic B44 E coli; group 3—orally given deferoxamine (50 mg/kg, twice a day); group 4—orally given gallium (4 mg/ kg; twice a day). Calves were studied for 8 days; blood samples were obtained each day (day 1 through day 8) for hematologic and serum biochemical analyses. There were significant increases in serum iron concentration and % saturation in all calves within 24 hours of iron-dextran administration, which returned to base-line values in all but group 4 (given gallium) within 3 days. In the exceptional group (4), total iron-binding capacity decreased with time, as in the other groups, but serum iron concentration remained significantly increased, implying gallium interference with systemic iron assimilation. Serum Zn concentrations were decreased, and Cu concentrations increased in association with the onset of fever, diarrhea, and hypoglycemia in all treated groups (2, 3, and 4). Although mean corpuscular volume gradually decreased with time in all groups, there were no major treatment effects on hematologic variables (erythrocyte numbers or hemoglobin concentrations) during the study. Although the expected trace element responses to intestinal disease were seen in groups 3 (deferoxamine treatment) and 2 (given B44 E coli), gallium treatment (group 4) may have antagonized systemic iron kinetics without improving host response to disease.
Heterotransplantation of canine sarcoma cells (BLU284) in athymic (nude) mice
Authors: Aaronson Laura M. , Pardini Lani L. , Pardini Ronald S.
Published: February 2025

Undifferentiated canine sarcoma cells from a primary lesion were implanted subcutaneously in athymic (nude) mice. Tumors were implanted at 2 sites in each of 4 mice, and 6 of the 8 inoculation sites developed into tumors. Tumors grew and invaded surrounding tissues, as shown by histologic examination. Karyotype analysis verified that tumors were of canine origin. Cells from this tumor were serially heterotransplanted 26 times without consistent change in growth rate. Once established in nude mice, samples from 2 generations of this canine sarcoma cell line were stored cryogenically and were implanted into nude mice. Over 26 generations, 93.7% of fresh implants developed into tumors. Preliminary screening of antineoplastic drugs indicated that this tumor line was sensitive to cyclophosphamide and vincristine. The difference in sensitivity of this heterotransplanted tumor in nude mice toward the various antineoplastic agents provides a useful model for the elucidation of biochemical bases of antineoplastic drug resistance in tumors.
Gastric spirillosis in Beagles
Authors: Henry G. A. , Long P. H. , Burns J. L. , Charbonneau D. L.
Published: February 2025

Light microscopic, ultrastructural, and microbiologic evaluations were performed on stomachs from 30 healthy laboratory-reared Beagles. Spiral-shaped microorganisms were seen in the gastric glands and parietal cell canaliculi of all the dogs. Organisms were most numerous in the cardia and in the region of the fundic-pyloric junction. Lymphoreticular hyperplasia, dilatation of parietal cell canaliculi, and degeneration of individual parietal cells (rarely seen) were the only morphologic alterations seen. Organisms were helical, had tufts of flagella at each end, and were approximately 0.5 × 7.0 µm; some had a distinct axial fibril (indicating two distinct forms of the organism). Attempts to propagate a viable culture of the organism were not successful.

The organism most closely resembled those of the genus Spirillum. Because the organism was commonly found in the gastric mucosa of healthy Beagles, it probably should be considered part of the natural gastric flora of dogs.
Actinobacillus suis-like organisms in horses
Authors: Jang Spencer S. , Biberstein Ernst L. , Hirsh Dwight C.
Published: February 2025

Actinobacillus suis-like organisms have been recognized in equine specimens at the University of California Veterinary Medical Teaching Hospital since 1975. The most common source (65%) of the organism was transtracheal washings. The organism was gram-negative, produced hemolysis on blood agar, and gave a positive reaction for oxidase, urease, o-nitrophenyl-ß-d-galactopyranoside, and esculin. Carbohydrate reactions were variable, consisting of 4 main patterns. Actinobacillus suis-like organisms were (90%) sensitive to therapeutic concentrations of amikacin, cephalothin, chloramphenicol, gentamicin, kanamycin, tetracycline, and trimethoprim-sulfamethoxazole. Other aerobic and anaerobic bacteria were recovered frequently with the organism.
Rhinitis, pneumonia, and defective neutrophil function in the Doberman Pinscher
Authors: Breitschwerdt Edward B. , Brown Talmage T. , De Buysscher Edward V. , Andersen Burton R. , Thrall Donald E. , Hager Elizabeth , Ananaba Goodwin , Degen Melissa A. , Ward Marsha D. W.
Published: February 2025

Eight closely related Doberman Pinschers with chronic rhinitis and pneumonia had normal or increased numbers of structurally normal leukocytes. Serum concentrations of immunoglobulins and complement were above or within normal ranges. Lymphocyte transformation indices for 3 mitogens were normal in 7 of the 8 dogs; the remaining dog had low values for all mitogens. Neutrophils phagocytized bacteria normally, but had impaired bactericidal ability. The bactericidal defect may have been related to the inability of neutrophils to generate normal numbers of oxygen radicals after stimulation, as determined by decreased ability of neutrophils to reduce nitroblue tetrazolium and to produce superoxide following opsonized zymosan stimulation. These observations, plus finding chronic inflammatory disease in the lungs of one dog, indicated that the disease may have some similarity to chronic granulomatous disease or to complement receptor deficiency in man.
Plasma lidocaine concentrations in conscious horses after cervicothoracic (stellate) ganglion block with 1% lidocaine HCl solution
Authors: Skarda Roman T. , Muir William W. , Couri Daniel
Published: February 2025

Arterial and/or central venous plasma concentrations of lidocaine were determined in 12 nonmedicated adult horses (422 ± 59 kg of body weight, mean ± sd) after injecting a 1% lidocaine HCl solution into the cervicothoracic ganglion (ctg). A mean dosage of 2.9 ± 0.5 mg of lidocaine/kg of body weight was used to induce unilateral ctg blockade in 8 horses and 4.8 ± 0.8 mg was used to induce bilateral ctg blockade in 4 horses. Blood samples were collected before and at 5, 15, 30, 45, 60, 75, 90, 105, and 120 minutes after injection. The plasma lidocaine concentrations were determined by use of gas chromatography (sensitivity < 0.01 µg/ml).

Cervicothoracic sympathetic blockade was characterized by Horner's syndrome and by profuse sweating over the face, neck, and thoracic limbs. Mean maximal venous concentrations of lidocaine were 0.86 ± 0.33 µg/ml at 26.3 ± 6.9 minutes after unilateral ctg blockade, and 1.14 ± 0.25 µg/ml at 31.2 ± 18.9 minutes after bilateral ctg blockade. The mean venous and arterial concentrations of lidocaine were not significantly different at 45 and 120 minutes after injection. Venous concentrations of lidocaine were consistently higher than were concentrations in simultaneously collected arterial blood samples in 2 horses in which the right ctg and brachial plexus were temporarily anesthetized after repeated administration of 100 ml of lidocaine into the right ctg.

The plasma lidocaine concentrations determined during unilateral and bilateral ctg blockades did not induce direct systemic effects on the cardiovascular system (ie, heart rate and arterial blood pressure) and did not have an effect on selected laboratory data (ie, arterial pH and total protein concentration). Clinical signs of systemic toxicosis were not observed.
Effects of etomidate on adrenocortical function in canine surgical patients
Authors: Kruse-Elliott Kris T. , Swanson Clifford R. , Aucoin David P.
Published: February 2025

Adrenocortical function in canine surgical patients given etomidate at 1 of 2 dosages (1.5 mg/kg of body weight or 3 mg/kg, iv) was evaluated and compared with that of dogs given thiopental (12 mg/kg, iv). The adrenocortical function was evaluated by use of adrenocorticotropic hormone (acth) stimulation tests and determination of plasma Cortisol concentrations at 0 minute (base line) and 60 minutes after acth administration. At 24 hours before administration of either drug (ie, induction of anesthesia), each dog had an increase in plasma Cortisol concentration when given acth. The acth stimulation tests were repeated 2 hours after induction of anesthesia. Dogs given thiopental had base-line plasma Cortisol concentrations greater than preinduction base-line values, but did not increase plasma Cortisol in response to acth stimulation. Postinduction acth stimulation tests in dogs given etomidate at either dose indicated base-line and 60-minute plasma Cortisol concentrations that were not different from preinduction base-line values. Therefore, adrenocortical function was suppressed 2 and 3 hours after the administration of etomidate in canine surgical patients.
Effects of collection time and food consumption on the urine protein/creatinine ratio in the dog
Authors: Jergens Albert E. , McCaw Dudley L. , Hewett John E.
Published: February 2025

Effects of collection time and food consumption on the variability of the urine protein/creatinine ratio were determined in 10 healthy dogs. In trial 1, dogs were fasted for 12 hours, and urine specimens were obtained by bladder catheterization every 2 hours over an 8-hour collection period during the day. After a 1-week rest, the dogs were entered into trial 2. Dogs were fed at least 60 kcal of a high protein meal/kg of body weight, and urine specimens were obtained every 2 hours over an 8-hour period during the day. Urine total protein and urine creatinine concentrations and the urine protein/creatinine ratio were determined for each urine specimen obtained.

Friedman's 2-way analysis by ranks was used to determine the constancy of this ratio over the 4 periods in the 2 trials (fasted and fed). There was no significant variability (P > 0.05) in ratios over the 8-hour collection periods in the fasted or fed trial. Feeding did not significantly alter this ratio, because there was no significant difference (P > 0.05) in the urine protein/creatinine ratios of the dogs when they were fasted, compared with those of the dogs when they were fed. Seemingly, urine specimens obtained anytime during the day from dogs in both trials (fasted and fed) reflected the urine protein/creatinine ratio.
Evaluation of neutrophil function in female goats
Authors: Maddux Jeanne M. , Keeton Kerry S.
Published: February 2025

Polymorphonuclear neutrophils (pmn) were isolated from the blood of healthy adult female goats on each of 3 consecutive days. The pmn isolated were evaluated, using random migration, Chemotaxis, Staphylococcus aureus ingestion, cytochrome C reduction, iodination, and antibody-dependent cell-mediated cytotoxicity assays. Over the 3 days, mean values for each of the assays ranged as follows: area of random migration, 11.3 to 19.9 mm2; chemotactic index, 6.4 to 11; chemotactic difference, 2.8 to 4.2 mm; S aureus ingestion, 18.3% to 26.1% ingested; cytochrome C reduction, 2.7 to 3.2 nmoles of O2− produced/ well; iodination, 19.4 to 25.1 nmoles of NaI/107 pmn/h; and antibody-dependent cell-mediated cytotoxicity 59% to 90% 51Cr released. Significant (P < 0.05) day-to-day variations were found for all assays. Parallel increases and decreases for all test results on a per day basis indicated a common denominator influencing cell functional status rather than variability inherent in the assays themselves. Alterations induced in the cells during the cell isolation procedure were considered a probable cause.
Neurophysiologic maps of cutaneous innervation of the external genitalia of the ram
Authors: Kirk E. J. , Kitchell R. L. , Carr D. H.
Published: February 2025

The area of skin innervated by the afferent fibers in a peripheral nerve is called the cutaneous area (ca) of that nerve. Mapping of those areas that were responsive to movement of wool/hairs in the genital region of 18 anesthetized rams, combined with subsequent identification of spinal nerves and dissection of the pudendal nerve plexus, indicated considerable differences in the extent of the ca and the origins of cutaneous branches from the pudendal plexus. The ca of the proximal and distal cutaneous branches of the pudendal nerve (or plexus) overlapped craniocaudally by approximately one-half, and the latter included most of the skin of the ipsilateral half of the scrotum. The ca of the deep perineal and caudal rectal nerves lay immediately adjacent to the anus. The ca of the scrotal branches of the pudendal nerve were restricted primarily to the scrotum. Fascicles in the dorsal nerve of the penis irregularly supplied ca along the length of the prepuce and consistently supplied the cranial free end of the prepuce. The ca of the ventral cutaneous branches of the caudal thoracic spinal nerves, the first 2 or 3 lumbar spinal nerves, and the genitofemoral nerve extended to the midline of the prepuce. Overlapping of ca was extensive, especially on the prepuce.
Arterial and venous supply to the bovine jejunum and proximal part of the ileum
Authors: Levine Susan A. , Smith Donald F. , Wilsman Norman J. , Kolb David S.
Published: February 2025

The blood vasculature of the bovine jejunum and proximal part of the ileum was studied in 20 mature dairy cows at slaughter. The cranial mesenteric artery and vein supplied the jejunum and ileum, and their major branches were present in all specimens and supplied similar regions of the intestinal tract. Proximal branches of the cranial mesenteric artery were pancreatic arteries, caudal pancreaticoduodenal artery, middle colic artery, and ileocolic artery. A large collateral branch arose from the proximal segment of the cranial mesenteric artery, anastomosing with the continuation of the cranial mesenteric artery distally along the jejunum. Jejunal arteries arose from the continuation of the cranial mesenteric artery, forming a series of anastomosing arches. Straight vessels arising from these arches did not branch or anastomose before entering the serosal layer of the intestine. The proximal part of the ileum was supplied by branches from the continuation of the cranial mesenteric artery; these branches anastomosed with the mesenteric ileal (ilei mesenterialis) artery, a branch of the ileocolic artery. The venous supply paralleled the arterial supply in all specimens.
Electroretinography in Labrador Retrievers given ketamine-xylazine anesthesia
Authors: Kommonen Bertel , Raitta Christina
Published: February 2025

Electrophysiologic examination of scotopic and photopic retinal function was done in 31 young healthy Labrador Retrievers and 6 Labrador Retrievers with ophthalmoscopic signs of generalized progressive retinal atrophy (pra). Scotopic responses to 4 stimulus intensities (b-wave threshold and 0.65-, 1.60-, and 2.59-log relative units above b-wave threshold, tests 1, 2, 3, and 6, respectively) were determined, using single-flash stimulation. Alternating current recorded single-flash c waves (stimulus intensity 3.18-log relative units above b-wave threshold, test 4) and 30-Hz photopic flicker (stimulus intensity 1.92-log relative units above b-wave threshold, test 7) responses were recorded.

Results of the single-flash recordings from 31 healthy dogs were analyzed statistically. The method used allowed for a separation of rod and cone function. Tests 3, 6, and 7 were most useful in determination of retinal disease, when results of the healthy young dogs were compared with results obtained from generalized pra-affected dogs. Various doses of ketamine and xylazine in dogs with ophthalmoscopically normal fundi had no significant effects on a- and b-wave amplitudes when dogs were given single-flash stimuli 1.60-log relative units above b-wave threshold (test 3).

Three 3-year-old dogs, with ophthalmoscopic signs of generalized pra, had greatly reduced a- and b-wave amplitudes and unaltered or slightly shortened a- and b-wave latencies. One 3-year-old dog with normal-appearing fundi had responses similar to those of dogs with generalized pra of the same age. On repeated examination 6 months later, this dog had ophthalmoscopic and angiographic signs of generalized pra. These four 3-year-old dogs had 30-Hz photopic flicker responses of normal latency and slightly lowered amplitude. Two 5-year-old dogs had ophthalmoscopic signs of advanced generalized pra and isoelectric responses including isoelectric 30-Hz flicker responses.

The cone response was slightly decreased at a stage when the rod response was already severely altered. Electrophysiologic findings correlated well with ophthalmoscopic findings (except in 1 dog) and with age. Electrophysiologic findings combined with ophthalmoscopic findings in dogs of different ages indicated that the type of generalized pra described may be a generalized progressive rod-cone dystrophy.
Clearance of indocyanine green in dogs with partial hepatectomy, hepatic duct ligation, and passive hepatic congestion
Authors: Rakich Pauline M. , Prasse Keith W. , Bjorling Dale E.
Published: February 2025

Clearance of 5 submaximal doses of indocyanine green (icg) was measured in 5 dogs to determine the maximal removal rate (0.188 mg/kg of body weight/min) and Michaelis constant (Km, 1.25 mg/kg). From these results, 5 mg of icg/kg of body weight was chosen on the basis of the recommendation that the dose should be at least 4 × Km, to achieve sensitivity as a measure of hepatic function and independence from hepatic blood flow. Clearances of low (0.5 mg/kg) and high (5 mg/kg) doses of icg were measured in 35 healthy dogs to determine reference values. Fractional disappearance was 15.1 ± 10%/min for the low dose and 3.9 ± 1%/min for the high dose; plasma half-life was 6.3 ± 3.6 minutes and 19 ± 4.8 minutes, respectively.

The sensitivity of 2 doses of icg was evaluated in dogs with 20% and 40% hepatectomy, nonhyperbilirubinemic obstructive cholestasis, or hepatic congestion; sham-operated dogs served as controls. Fractional disappearance and plasma half-life of icg in the 40% hepatectomy and hepatic congestion groups were significantly different (P < 0.05) from those in controls using both icg doses, indicating that both doses were affected by hepatic perfusion, as well as hepatic mass. The fractional disappearance of the dye in the cholestasis group also differed significantly (P < 0.05) from that of the controls at the high dose. Plasma clearance of both doses by dogs with 20% hepatectomy was not significantly different from that of controls.
Induction and characterization of acrosome reaction in equine spermatozoa
Authors: Varner Dickson D. , Ward Cynthia R. , Storey Bayard T. , Kenney Robert M.
Published: February 2025

Equine spermatozoa were incubated in a chemically defined medium for 8 hours. The medium preserved spermatozoal viability, as assessed by total spermatozoal motility, progressive spermatozoal motility, and spermatozoal exclusion of eosin stain. Effects of time and divalent cation ionophore, A23187, on the occurrence and character of the spermatozoal acrosome reaction were determined. Two light microscopic assays, a triple-stain technique and a chlortetracycline fluorescence assay, were calibrated with transmission electron microscopy for detection of the acrosome reaction. Incubation time and A23187 addition increased the percentage of acrosome reactions in sperm populations (P < 0.05).
A vaccine strain of pseudorabies virus with deletions in the thymidine kinase and glycoprotein X genes
Authors: Marchioli C. C. , Yancey R. J. , Wardley R. C. , Thomsen D. R. , Post L. E.
Published: February 2025

A Pseudorabies virus (prv) mutant with deletions in genes for glycoprotein X (gX) and thymidine kinase, designated ΔGXΔTK, was constructed and evaluated as a vaccine for protecting swine against prv-induced mortality. Doses ≥ 103 plaque-forming units (pfu) of this strain given to mice provided protection from challenge exposure with virulent prv. Sera tested from mice inoculated with ΔGX ΔTK had high titers of neutralizing antibody to prv, but reactivity in the same sera was not significantly different from that in sera from noninoculated mice (controls) when sera from both groups were evaluated by use of an elisa with gX antigen produced in Escherichia coli. Compared with noninoculated pigs (controls), those given ΔGXΔTK (≥102 pfu) were protected completely from lethal challenge exposure, without experiencing adverse effects on weight gain and with reduction of shedding of virulent challenge virus. Serotest results indicated that, although inoculated pigs responded with strong neutralizing antibody titers, the response of ΔGXΔTK-inoculated pigs to gX, as determined by elisa before challenge exposure, was not significantly greater than the elisa values obtained from control pigs. The elisa values from a group of pigs inoculated with a commercially available vaccine were significantly (P < 0.05) higher than those of control pigs. The experimental vaccine, ΔGXΔTK, was avirulent for mice, swine, and sheep, but was mildly virulent for calves (mortality, 1 of 12) and more virulent for dogs (mortality, 3 of 6) and cats (mortality, 2 of 6). These results indicate that this constructed attenuated vaccine might be used to protect swine from prv and, coupled with an elisa specific for gX, might allow differentiation of vaccinated pigs from those exposed to field-type virus.
Effect of intravenous administration of dextrose or lactated Ringer's solution on seizure development in dogs after cervical myelography with metrizamide
Authors: Gray Peter R. , Lowrie Charles T. , Wetmore Lois A.
Published: February 2025

The effect of fluid (5% dextrose in water or lactated Ringer's solution) administered intravenously on the development of seizures after cervical myelography with metrizamide was studied in 10 dogs. In a crossover experimental design, 8 dogs were used twice. Urine output was measured during the second part of the study to determine whether diuresis was a factor affecting seizure development.

Dogs given 5% dextrose in water had significantly (P < 0.05) fewer seizures than did dogs given lactated Ringer's solution. This was attributed to an increase in CSF glucose concentration and was not associated with diuresis.
Effect of antigenic modulation and phase variation on adherence of Bordetella bronchiseptica to porcine nasal epithelial cells
Authors: Ishikawa Hitoshi , Isayama Yasuro
Published: February 2025

In parallel with bacterial density, Bordetella bronchi-septica phase-I, X-mode cells adhered well to porcine nasal epithelial cells, whereas C-mode cells and variant cells in phases II, III, and rough adhered feebly. Cell surface components lost, on transition from X to C mode or from phase I to degraded phases, may confer much of the organism's adherence ability.
Immunostimulation in mice infected with Sendai virus
Authors: Brownstein David G. , Weir Eleanor C.
Published: February 2025

The effect of Sendai virus infection on the splenic primary plaque-forming cell (pfc) response to sheep rbc in 2 strains of mice, with contrasting susceptibility to Sendai viral pneumonia, was examined. Mice were given single inoculations of sheep rbc, which varied relative to time of inoculation with Sendai virus, pfc were counted 6 days later, and were compared with pfc responses from noninfected mice. The IgM- and IgG-pfc responses were augmented in resistant C57BL/6J mice 7 and 9 days after inoculation with Sendai virus (sheep rbc given 1 and 3 days after inoculation with Sendai virus, respectively) and in susceptible DBA/2J mice 7, 9, 10, and 13 days after inoculation with Sendai virus. Augmentation was restricted mainly to IgM-, IgG3-, and IgG2b-pfc.

The number of splenic background antitrinitrophenyl sheep rbc pfc in mice of both strains was examined during the course of Sendai virus infection. Only a marginal increase in background pfc was seen in C57BL/6J mice on or after viral inoculation day 11 and no change was seen in DBA/2J mice. Serum of infected mice also was examined sequentially for α/β interferon (ifn). Despite vigorous lung ifn production, infected mice rarely had detectable circulating ifn. Seemingly, Sendai virus infection can induce transient hyperresponsiveness to a nonviral antigen.
Plasma, red blood cell, total blood, and extracellular fluid volumes in healthy horse foals during growth
Authors: Spensley Michael S. , Carlson Gary P. , Harrold Doris
Published: February 2025

During the growth interval encompassing age 2 days through 24 weeks, plasma, rbc, total blood, and extracellular fluid (ecf) volumes were determined in 7 healthy, resting foals. Evans blue dye and sodium thiocyanate were used to estimate plasma and ecf volumes, respectively. Absolute plasma volume remained stable from 2 days through 2 weeks of age, then increased progressively through 24 weeks of age. After decreasing between 2 days and 2 weeks of age, absolute rbc and total blood volumes progressively increased. Absolute ecf volume increased progressively from 2 days of age through 24 weeks of age, but plasma, rbc, and total blood volumes decreased relative to body weight increase. During the first 12 weeks of life, ecf volume decreased relative to body weight increase, and then remained stable during the next 12 weeks. There were close correlations between age, as well as body weight, and plasma, rbc, total blood, and ecf volumes. The relationship defined between age and the respective fluid and blood volumes provided a useful tool for evaluation and management of alterations of fluid balance in the foal.
Plasma endogenous ACTH concentrations and plasma cortisol responses to synthetic ACTH and dexamethasone sodium phosphate in healthy cats
Authors: Smith Marcia C. , Feldman Edward C.
Published: February 2025

Plasma Cortisol responses of 19 healthy cats to synthetic acth and dexamethasone sodium phosphate (dsp) were evaluated. After administration of 0.125 mg (n = 5) or 0.25 mg (n = 6) of synthetic acth, im, mean plasma Cortisol concentrations increased significantly (P < 0.05) at 15 minutes, reached a peak at 30 minutes, and decreased progressively to base-line values by 120 minutes. There was no significant difference (P > 0.05) between responses resulting from the 2 dosage rates. After administration of 1 mg of dsp/kg of body weight, iv (n = 7), mean plasma Cortisol concentrations decreased at postadministration hour (pah) 1, and were significantly lower than control Cortisol concentrations at pah 4, 6, 8, 10, and 12 (P < 0.01). Administration of 0.1 mg of dsp/kg, iv (n = 8) or 0.01 mg of dsp/kg, iv (n = 14) induced results that were similar, but less consistent than those after the 1 mg of dsp/kg dosage. Mean plasma Cortisol concentrations returned to base-line values by pah 24. There was not a significant difference between the 3 doses (P > 0.05) at most times. Measurement of endogenous acth in 16 healthy cats revealed plasma acth of < 20 to 61 pg/ml.

Seemingly, administration of synthetic acth consistently induced a significant (P < 0.05) adrenocortical response in healthy cats. On the basis of time-response studies, post-acth stimulation Cortisol samples should be collected at 30 minutes after acth administration to ensure detection of peak adrenocortical response. Administration of dsp at 0.01,0.1, or 1 mg/kg suppressed plasma Cortisol concentrations in the cat; post-dsp Cortisol samples should be collected at 6 to 10 hours after dsp administration. These adrenocortical function tests can be used reliably to evaluate the hypophysis-adrenal axis in the healthy cat.
Morphologic comparison of healing patterns in ethylene oxide-sterilized cortical allografts and untreated cortical autografts in the dog
Authors: Johnson Ann L. , Stein L. E.
Published: February 2025

Full-thickness canine cortical allografts were harvested cleanly, sterilized with ethylene oxide, and stored at 22 C. The sterilized allografts were incorporated into segmental, femoral fracture repairs and evaluated for 6 months. Allografts were compared with untreated cortical autografts, which also were incorporated into segmental, femoral-fracture repairs for 6 months. Sequential fluorochrome labeling at 8, 11, 21, and 24 weeks after surgery made it possible to evaluate retrospectively the time of new bone formation. Morphometric evaluations were made of the numbers of labeled haversian systems, the percentage of labeled bone, and the porosity of the bone. The cortical allografts had bone formation in the proximal and distal portions of the graft, with the greatest activity at 5 to 6 months after surgery. Activity in the center of the allograft was minimal. Cortical autografts had bone formation throughout the graft, with the greatest number of haversian systems labeled at 3 months after surgery. We concluded that cortical allografts heal and remodel more slowly and in a different sequence of events than do cortical autografts.
Synergistic effects of Fusobacterium necrophorum lipopolysaccharide, cytoplasmic, and culture supernatant fractions on induction of acute hepatic necrosis in rabbits
Authors: Nakajima Yasuyuki , Ueda Hisashi , Takeuchi Syotaro
Published: February 2025

Synergistic effects of toxic fractions of Fusobacterium necrophorum were examined for evaluation of the role of the toxin in inducing liver abscesses in rabbits. Cytoplasmic and culture supernatant fractions of F necrophorum had preparative activity for the Shwartzman reaction, and lipopolysaccharide of F necrophorum had preparative and provocative activities for the reaction. All 3 fractions were hepatotoxic. Inoculation into the bile duct with each fraction followed by intravenous inoculation with F necrophorum or Escherichia coli lipopolysaccharide had a greater synergistic effect in inducing severe hepatic necrosis than did inoculations with double doses of the cytoplasmic or supernatant fractions of F necrophorum. This synergism may have been attributable to the Shwartzman reaction.
Effects of topical application of amitraz on plasma glucose and insulin concentrations in dogs
Authors: Hsu Walter H. , Schaffer David D.
Published: February 2025

Amitraz, a formamidine insecticide, is used topically in the treatment of demodicosis and other ectoparasitic infestations. When 3.78 L (containing 2.1 g) of amitraz (twice the recommended concentration) was applied to 5 dogs 4 hours before glucose (0.6 g/kg of body weight) was administered iv, plasma glucose concentration increased, but the increase in plasma insulin concentration, which usually follows iv administered glucose, was suppressed. The results suggested that amitraz induced hyperglycemia at least partly by inhibiting insulin release.
Hemodynamics, plasma eicosanoid concentrations, and plasma biochemical changes in calves given multiple injections of Escherichia coli endotoxin
Authors: Templeton C. B. , Bottoms G. D. , Fessler J. F. , Turek J. J.
Published: February 2025

Twelve male neonatal calves (39 to 50 kg) were allotted to 3 groups of 4 calves each. All calves were anesthetized with halothane, and then Escherichia coli endotoxin was given intravenously (3 times) and intraperitoneally (3 times) during a 6-hour period. Group-1 calves were untreated, group-2 calves were pretreated with a low dose of flunixin meglumine (1.1 mg/kg of body weight), and group-3 calves were pretreated with a high dose of flunixin meglumine (4.4 mg/kg).

In calves of group 1, the mean systemic arterial blood pressure (mabp) and cardiac output (co) decreased, but pulmonary arterial pressure increased after the initial intravenous and intraperitoneal injections of endotoxin. In calves of this group, these changes were accompanied by increased plasma thromboxane B2 (TxB2) concentration. During this period, increased plasma TxB2 concentration or hemodynamic changes were not detected in calves of groups 2 and 3. Only calves of group 1 had altered hemodynamics early in the experiment; however, after 6 hours, calves of all 3 groups had similarly decreased co and mabp.

In calves of the untreated group, plasma 6-keto-prostaglandin (pg)F1α concentration increased steadily from the beginning of the experiment until 3 hours later. The co and mabp were low at the time when serum 6-keto-pgf1α concentration was high; however, these 2 measurements also were low in treated calves who did not have correspondingly high plasma 6-ketopgf1α concentration. Regional blood flow analysis did not reveal correlations between prostanoid concentrations and altered blood flow to selected tissues.

Results indicated that endotoxin given to calves caused increases in plasma TxB2 and 6-keto-pgf1α concentrations, along with hemodynamic changes similar to those observed in other species. Flunixin meglumine (1.1 mg/kg) administration prevented the increase in plasma eicosanoid concentrations and the associated hemodynamic changes during early shock. However, in treated calves, after 3 hours, the co and mabp also were decreased without a corresponding increase of plasma 6-keto-pgf1α concentration. Therefore, something other than increased prostacyclin accumulation may have caused the later decrease in co and mabp.
Enzyme-linked immunosorbent assay for the detection of antibodies to the alcelaphine herpesvirus of malignant catarrhal fever in exotic ruminants
Authors: Wan Saio-Kun , Castro Anthony E. , Heuschele Werner P. , Ramsay Edward C.
Published: February 2025

An elisa for antibodies to the alcelaphine herpesvirus-1 of malignant catarrhal fever was developed. Of sera that represented 42 exotic ruminant species, 216 were evaluated by the elisa and a virus-neutralization test. A significant correlation (r = 0.564, P < 0.001, n = 216) between the elisa and virus-neutralization test results was found. Of the sera having positive test results by virus neutralization, 86.1% also had positive results by the elisa, and of the sera having negative test results by virus neutralization, 83.9% also had negative results by the elisa. The presence of antibody, as measured by the elisa, correlated with clinical signs of malignant catarrhal fever and the isolation of herpesvirus.
Oral administration of an attenuated strain of canine adenovirus (type 2) to raccoons, foxes, skunk, and mongoose
Authors: Sumner John W. , Shaddock John H. , Wu Guang-jer , Baer George M.
Published: February 2025

An attenuated strain of canine adenovirus type-2 (cav-2) was administered orally to 2 foxes (Vulpes fulva), 6 raccoons (Procyon lotor), a skunk (Mephitis mephitis), and a mongoose (Herpestus auropunctatus). Blood was collected weekly from the animals to monitor cav-2 virus-neutralizing antibody titers. All animals had increases in titers. Sera from 8 foxes, 30 mongooses, 52 raccoons, and 22 skunks trapped in the field had naturally occurring antibody to cav-2.
Experimental induction of abdominal tympany, abomasitis, and abomasal ulceration by intraruminal inoculation of Clostridium perfringens type A in neonatal calves
Authors: Roeder B. L. , Chengappa M. M. , Nagaraja T. G. , Avery T. B. , Kennedy G. A.
Published: February 2025

The etiologic role of Clostridum perfringens type A in the acute abdominal syndrome characterized by abomasal and rumen tympany, abomasitis, and abomasal ulceration was investigated in neonatal calves. Eight calves, 4 to 12 days old, were inoculated intraruminally with toxigenic C perfringens type A. Before and after C perfringens inoculation, blood samples were collected from all calves for blood gas and serum biochemical analysis and for determination of serum copper concentration; ruminal fluid was obtained for isolation of C perfringens. Calves were monitored daily for clinical signs of the syndrome and, depending on the severity of clinical signs, they were either euthanatized or redosed within 4 to 7 days. After necropsy, specimens obtained from the abomasum and rumen for macroscopic and microscopic examination and for anaerobic bacteriologic culture were processed in routine manner.

Intraruminal inoculation of C perfringens type A into healthy calves induced anorexia, depression, bloat, diarrhea, and in some calves, death. Serum copper concentration was within normal range. Necropsy revealed variable degrees of abomasitis, petechial and ecchymotic hemorrhages, and ulcers (ranging from pinpoint to nearly perforate) in the abomasum. Seven of those calves also had multiple trichobezoars in the rumen. These necropsy findings were not seen in calves (controls) given distilled H2O only. In affected calves, acute abdominal syndrome was unrelated to copper deficiency, and C perfringens type A given intraruminally was able to induce clinical signs similar to those of the naturally acquired disease.
Suppression of feline bone marrow fibroblast colony-forming units by feline leukemia virus
Authors: Wellman Maxey L. , Kociba Gary J. , Mathes Lawrence E. , Olsen Richard G.
Published: February 2025

Bone marrow fibroblast colony-forming units (cfu-f) were evaluated in cats experimentally infected with feline leukemia virus (FeLV). Cats that developed persistent viral infection and anemia (progressor cats) had a progressive decrease in the number of cfu-f at 2, 4, 6, 8, and 10 weeks after inoculation with FeLV. This suppression of cfu-f number in progressor cats ranged from 16 to 44% of the preinoculation cfu-f value. Cats that did not develop persistent viral infection or anemia (regressor cats) had decreased numbers of cfu-f (24% of the preinoculation cfu-f value) at 2 weeks after inoculation, but normal cfu-f numbers at 4, 6, 8, and 10 weeks after inoculation.

In vitro incubation of bone marrow mononuclear cells from healthy cats with the 15,000-dalton envelope protein of FeLV resulted in decreased number of cfu-f (21% of that of untreated cultures). The number of cfu-f from bone marrow mononuclear cells incubated with the 27,000-dalton core protein of FeLV was similar to that from untreated cultures.
Measurements of bone strain in foals with altered foot balance
Authors: Firth E. C. , Schamhardt H. C. , Hartman W.
Published: February 2025

Two to 7 days after birth, 9 foals were anesthetized, and strain gauges were applied to lateral and medial aspects of the third metacarpal bone of the left forelimb. In 5 of these foals, strain gauges also were applied to the radius of the left forelimb. Four to 6 days later, foals were walked (5 sets of 10 to 20 strides), and compressive and tensile strains in the bone beneath strain gauges were recorded on paper and diskette. After recording base-line data, a wedge was fitted to the hoof of the limb with the strain gauges, in such a way that the lateral bearing surface was raised, and strains were recorded again. The wedge was left in place, and further recordings were made every 2 to 3 days for 10 days.

At the normal walk (base-line data), the compressive strain was higher than the tensile strain in the third metacarpal bone, on the medial side of which the mean principal compressive strain was approximately twice that on the lateral surface. Immediately after application of the wedge, strain values from the medial surface of the third metacarpal bone decreased by 40%, and the lateral surface compressive strain increased by 100%. These changes gradually decreased over 10 days, at which time there was no significant difference from base-line values (P < 0.05). Similar but much less obvious trends were observed in the radius. Abnormal hoof balance apparently had no lasting effect on compressive forces running through the limb, and the natural situation of higher compressive strain medially was restored quickly.
Histopathologic findings in Brucella abortus-infected, pregnant goats
Authors: Meador V. P. , Hagemoser W. A. , Deyoe B. L.
Published: February 2025

Twenty-eight pregnant goats in midgestation were exposed to a bovine pathogenic strain of Brucella abortus to determine the histologic changes associated with infection. Does were necropsied 0 to 7 days or 4 to 6 weeks after delivery of aborted, stillborn, or live, full-term fetuses. Aborted and stillborn fetuses were necropsied within 16 hours of delivery. Selected, paired tissue specimens were collected for histologic and bacteriologic examination. An avidin-biotin-peroxidase complex immunostaining procedure was used to detect Brucella antigen in tissue section.

Histologic changes were evident in specimens from infected does and aborted fetuses. Postpartum does had endometritis, lymphoid hyperplasia in lymph nodes and spleen, and lymphocytic mastitis. The most prominent finding in aborted fetuses was an interstitial pneumonia. Lesions in does and fetuses were similar to those described in Brucella-infected cows and fetuses; however, lesions were less consistently observed in goat fetuses than has been observed in bovine fetuses.

Brucella antigen was detected by immunoperoxidase staining within the cytoplasm of placental chorioallantoic trophoblastic cells, macrophages, neutrophils, and uterine epithelial cells. Also, stained brucellae were free in placental and fetal vascular lumens and in the interstitium of autolyzed fetal tissues.