bluuebunny/crossref_metadata_2025 huggingface dataset:
Topically applied benzathine cloxacillin for treatment of experimentally induced infectious bovine keratoconjunctivitis
Authors: Daigneault Josée , George Lisle W.
Published: January 2024

The efficacy of an ophthalmic ointment containing benzathine cloxacillin for treatment of infectious bovine keratoconjunctivitis was determined in 2 experiments. In the first experiment, Holstein calves (n = 6/group) were inoculated with Moraxella bovis and treated on postinoculation days 3 and 6 with either topically applied benzathine cloxacillin (250 mg/eye) or long-acting oxytetracycline formulation (20 mg/kg of body weight, im). A third group of inoculated calves remained untreated as controls. For the second experiment, 4 groups of calves (n = 6/group) were inoculated and treated on postinoculation days 3 and 6 with 50, 125, 250, or 375 mg of benzathine cloxacillin; a fifth untreated group served as controls. Ocular specimens were obtained for microbiologie culture, and eyes were observed and assigned a clinical score daily. Eyes were photographed on alternate days. Ulcer surface area was measured, using a planimeter.

In experiment 1, the week-2 ulcer surface area measurements for both groups of treated calves were smaller than those for controls. There was a greater frequency of M bovis isolation from the ocular secretions of controls than from those of benzathine cloxacillin-treated calves during postinoculation weeks 2 and 3. The number of M bovis isolations from the benzathine cloxacillin- and oxytetracycline-treated calves was not significantly different at any sample collection interval. On week 3, the scores of the benzathine cloxacillin-treated calves were smaller than those of controls.

In experiment 2, calves of the 250- and 375-mg groups had smaller ulcer surface area measurements than did controls on week 2. By week 3, calves of the 375-mg group had smaller scores than did controls. During postinoculation weeks 1 through 3, M bovis was isolated less frequently from the ocular secretions of calves of the 250- and 375-mg groups than from those of the control calves.
Pharmacokinetic and tissue residue characteristics of fenprostalene, a prostaglandin F2α analog, in swine
Authors: Spires H. R. , Bowen J. L. , Tomlinson R. V. , Donahue D. J.
Published: January 2024

Fenprostalene, a prostaglandin F2α analog, can be used to induce parturition in swine. As part of the approval process for that indication, pharmacokinetic characteristics of the absorption and elimination of fenprostalene and the depletion of drug residues from the principal edible tissues of swine were studied. Blood samples, urine, and feces were collected from 8 gilts (body weight, 95 ± 1.7 kg) for up to 72 hours after a single dose of 0.5 mg of 13,14-[3H]-fenprostalene in polyethylene glycol-400 was administered sc. At intervals of 24, 48, 72, and 168 hours after dosing, 2 gilts each were killed, and samples of liver, kidney, muscle, and abdominal fat were obtained for analysis. The mean (± sem) maximal concentration of fenprostalene radioequivalents in plasma (0.41 ± 0.05 nanogram-equivalents/ml; n = 8) was observed at 12 hours and decreased biexponentially, with half-lives of approximately 8 hours and 9 days. Mean cumulative recovery (n = 4) of the administered dose by 72 hours was 61.2 ± 5.9% in urine and 18.5 ± 2.6% in feces. The highest tissue fenprostalene concentration was in kidneys and liver, probably reflecting the role of those organs in excreting fenprostalene. Rates of depletion of fenprostalene equivalents from the injection site, kidneys, and liver were comparable with those previously observed in cattle.

The composition of residue in the liver of 2 gilts slaughtered 12 hours after sc administration of [3H]-fenprostalene was examined in a second study. Results suggested that approximately 4% of the total residue was pharmacologically potent fenprostalene or the carboxylic acid form of fenprostalene. Approximately 29% of the residue was extensively degraded to acidic metabolites. The remaining 67% was bound, nonextractable material.
Pharmacokinetics, inhibition of lymphoblast transformation, and toxicity of cyclosporine in clinically normal pigs
Authors: Vaden Shelly L. , Riviere J. Edmond
Published: January 2024

Pharmacokinetic variables were calculated from time-concentration data obtained after iv (10 mg/kg of body weight; n = 9) and oral (12.5 mg/kg to group A [n = 3]; 25 mg/kg to group B [n = 3]; and 50 mg/kg to group C [n = 3] pigs) cyclosporine (formerly, cyclosporine A) administration. Resulting mean (± sd) pharmacokinetic variables were as follows: half life of distribution, 0.96 (± 0.7) hours; half life of elimination, 7.71 (± 2.6) hours; volume of distribution at steady state, 4.47 (± 2.22) L/ kg; volume of the central compartment, 1.71 (± 0.78) L/ kg; and systemic clearance, 8.95 (± 2.7) ml/kg/min. Oral bioavailability was: overall 57 (± 19) %; group A, 44 (± 11) %; group B, 78 (± 15) %; group C, 48 (± 6) %. Time to peak concentration was 3.55 (± 0.88) hours. During the 22 days of daily oral cyclosporine administration, blood 24-hour trough concentrations were: group A, 224.3 (± 78.4) ng/ml; group B, 640.7 (± 174.6) ng/ml; and group C, 2,344 (± 1,095) ng/ml. Lymphoblast transformation stimulation index was suppressed in all pigs except 1, which had a corresponding cyclosporine concentration of 92.4 ng/ml. Minimal, although statistically significant, decreases in serum albumin and magnesium concentrations and increases in serum creatinine and urea nitrogen concentrations were evident in pigs of some treatment groups. Histologic examination of necropsy specimens revealed mild hepatic necrosis (n = 1 pig), renal tubular dilatation (n = 5), and pulmonary inflammation (n = 2). Pigs given 25 and 50 mg of cyclosporine/kg failed to gain weight.
Suspected ciliary dysfunction in Chinese Shar Pei pups with pneumonia
Authors: Dhein Cheryl R. , Prieur David J. , Riggs Michael W. , Potter Kathleen A. , Widders Philip R.
Published: January 2024

Chronic pneumonia was investigated in a litter of young Chinese Shar Pei in which 4 of 6 dogs were affected. Serum immunoglobulin concentrations (IgA, IgG, IgM) determined by radial immunodiffusion varied over time, but were not consistently lower in affected dogs, compared with control dogs. Two dogs that died had hydrocephalus and lymphoid depletion, in addition to severe bronchopneumonia. Evaluation of ciliary ultrastructure in 2 affected dogs revealed random orientation of adjacent respiratory tract or oviductal cilia and a greater number of microtubular disarrangements, compared with control dogs. In vivo tracheal mucociliary clearance of 99mtechnetium macroaggregated albumin was absent in 1 dog examined. The ciliary abnormalities were suspected to have resulted in an inefficient mucociliary transport system predisposing to the development of pneumonia. Further evaluation of 1 Chinese Shar Pei revealed lymphocyte mitogenesis results that were not consistently less than those of a control dog, normal total hemolytic complement values, and normal blood neutrophil chemotaxis.
Peroxidase-antiperoxidase and immunogold labeling of Salmonella typhimurium and Salmonella choleraesuis var kunzendorf in tissues of experimentally infected swine
Authors: Pospischil Andreas , Wood Richard L. , Anderson Timothy D.
Published: January 2024

Peroxidase-antiperoxidase immunoenzymatic labeling and immunogold labeling techniques were evaluated for microscopic detection and location of Salmonella organisms in tissues of experimentally infected swine. Salmonella typhimurium and Salmonella choleraesuis var kunzendorf were labeled specifically by the peroxidase-antiperoxidase technique in paraffin-embedded tissues of infected swine for conventional light microscopy and by postembedding immunogold labeling on ultrathin sections for electron microscopy. Salmonella typhimurium had a low tendency to invade the enteric mucosa and did not reveal any predilection for a specific intestinal location. Salmonella choleraesuis var kunzendorf, however, was located preferentially in colon and on the luminal surface of ileal M cells of Peyer patches and had a tendency to invade the enteric mucosa there.
Identification of a free skin flap from the region vascularized by the deep circumflex iliac artery of horses
Authors: Lees Michael J. , Bowen C. Vaughan , Fretz Peter B. , Leach Douglas H.
Published: January 2024

Areas of skin vascularized by large axial vessels potentially suitable for microvascular anastomosis were investigated in 10 horse cadavers. Eleven such areas were dissected, and the skin over the flank region vascularized by the deep circumflex iliac artery was most suitable. The anatomy of this area was further defined, using angiography and latex injection studies on 10 cadavers.
In vitro effects of cyclopiazonic acid mycotoxin on turkey papillary muscles
Authors: Miller Charles D. , Richard John L. , Hembrough Frederick B. , Osweiler Gary D. , Cox David F.
Published: January 2024

An in vitro bioassay system was used to study the effects of cyclopiazonic acid (cpa) mycotoxin on cardiac muscle. Acute exposure to 6 μg of cpa/ml of modified Krebs-Henseleit solution significantly (P < 0.05) decreased 5 in vitro turkey cardiac muscle performance criteria: maximal weight a muscle could lift; maximal contraction velocity; relaxation velocity; time to peak contraction; and total time for muscle contraction and relaxation. The effect on these 5 criteria appeared to result from intracellular changes partially associated with calcium availability and were irreversible, suggesting that physiologic changes had developed after acute exposure to cpa.
Clinicopathologic analysis of herpesvirus-induced urinary tract infection in specific-pathogen-free cats given methylprednisolone
Authors: Kruger John M. , Osborne Carl A. , Goyal Sagar M. , O'Brien Timothy D. , Pomeroy Kem A. , Semlak Ruth A.
Published: January 2024

The clinicopathologic manifestations of bovid herpesvirus-4 (bhv-4; FCAHV strain)-induced infection of the lower portion of the urinary tract were characterized in 12 adult neutered male and 6 female specific-pathogen-free cats, and were compared with those in 12 neutered male control cats. Six neutered male and 6 female cats were given immunosuppressive doses of methylprednisolone acetate prior to inoculation of their urinary bladders with bhv-4. Six neutered male control cats were given immunosuppressive doses of methylprednisolone acetate prior to inoculation of their urinary bladders with uninfected tissue culture control inoculum. Six additional neutered male control cats were exposed only to uninfected tissue culture control inoculum. All cats were observed for 90 days following inoculation. Dysuria and gross hematuria were observed in only 1 bhv-4-exposed cat. Radiographic abnormalities of the lower portion of the urinary tract were not observed. Microscopic hematuria, crystalluria, and lipiduria were identified with similar frequency in bhv-4-exposed and control cats. Results of urine culturing for bacteria, mycoplasma, ureaplasma, and viruses were negative. Viruses were not isolated from blood leukocytes collected from exposed or control cats. Three to 6 weeks after inoculation, high concentrations of bhv-4 serum antibodies were detected in all exposed cats by an indirect fluorescent antibody test.

Light microscopic examination of the urinary tract revealed multifocal lymphoid cystitis in 2 bhv-4-exposed cats. Except for suppurative bronchitis in 1 bhv-4-exposed cat given glucocorticoids, morphologic differences in urinary and extraurinary tissues were not observed. In urinary bladder tissue collected 90 days after inoculation, bhv-4 was reisolated from urinary bladder explants of all but 1 exposed cat. Virus was also isolated from a kidney explant of 1 exposed male cat, and spleen cell cocultures of 1 exposed female cat given glucocorticoids.

Bovid herpesvirus-4 (FCAHV strain) caused persistent urinary tract infections in male and female specific-pathogen-free cats. Detection of occult bhv-4 infection required isolation of virus from tissues by explantation, or demonstration of specific bhv-4 antibodies by immunofluorescent techniques. Administration of glucocorticoids prior to inoculation did not enhance morbidity associated with bhv-4 urinary tract infection. Further investigations are needed to determine the pathogenic role of bhv-4 in noninduced feline lower urinary tract disease.
Interferon and 2′,5′-oligo(A) synthetase activities in serum and blood mononuclear leukocytes of cattle after injection of bovine interferon-α1
Authors: Perino Louis J. , Short Everett C. , Burge Lurinda J. , Winter Douglas A. , Fulton Robert W.
Published: January 2024

Cell extracts that were prepared from blood mononuclear leukocytes from 66 samples obtained from 6 clinically normal calves contained mean 2′,5′-oligoadenylate (2′,5′-oligo[A]) synthetase activity sufficient to synthesize 186 ± 82 pmol of 2′,5′-oligo(A)/h/106 cells. Calves had no measurable serum interferon (ifn) activity. Five calves were given im injections of 104, 105, 5 × 105, 106, and 107 U of bovine ifn-α1/kg of body weight at 2-week intervals. Five dosing sequences were used with a 5 × 5 Latin square design so that each calf received each dose once. Activity of 2′,5′-oligo(A) synthetase increased at 24 hours in response to all dosages of ifn and then declined following first-order kinetics, with an apparent half-life (t½) of 2.1 ± 0.5 days. The area under the concentration-time curve for 2′,5′-oligo(A) synthetase increased with dose of ifn more rapidly than did peak response. Serum ifn that was measured at 1-day intervals following administration of ifn was consistently measurable only at dosages above 106 U of ifn/kg. The t½ for circulating ifn was 12.4 ± 1.0 hours. Over all dosages, increases in 2′,5′-oligo(A) synthetase activity were measurable for 3.5 days longer than were increases in ifn following im injection of ifn. None of the calves developed detectable anti-ifn antibodies.
Diagnosis of transplacentally induced toxoplasmosis in pigs
Authors: Dubey J. P. , Urban J. F.
Published: January 2024

Seventeen sows were fed 1,000 Toxoplasma gondii oocysts of isolates GT-1 or PT-1 at 32 to 92 days of gestation, and the products of conception were examined for T gondii anibodies and parasites. Twelve of these sows were euthanatized near term between 21 and 62 days after being fed T gondii; fetal body fluids or fetal sera were examined for agglutinating T gondii antibodies, and tissues were bioassayed in mice for T gondii parasites. Six sows produced pigs that had been transplacentally infected with T gondii; one of them aborted a T gondii-infected fetus 17 days after ingesting oocytes.

Agglutinating antibodies were detected in fetuses infected in utero, but transplacental transfer of T gondii antibodies was not observed in noninfected fetuses. Transcolostrally acquired T gondii antibodies disappeared by 3 months of age. Diagnosis of transplacental toxoplasmosis was confirmed on the basis of detection of T gondii organisms in fetal tissues by use of histologic examination and bioassay in mice. In conclusion, finding of T gondii antibodies in body fluids could serve as a rapid screening test for transplacental T gondii infection in pigs.
Alteration of intestinal enzyme activities associated with extensive large-colon resection in horses
Authors: Bertone Alicia L. , Toofanian Farshid , Stashak Ted S.
Published: January 2024

Lactase, maltase, sucrase, and alkaline phosphatase activities were determined in the intestinal mucosa from 3 locations in the small intestine and 4 locations in the large intestine 1 year after extensive large-colon resection (group 1; n = 5) and 1 year after sham operation (group 2; n = 3) in horses.

Lactase, maltase, and sucrase activities were similar (P > 0.05) between group-1 and group-2 horses in all locations measured in the intestinal tract. Alkaline phosphatase activity in the remaining large colon of group-1 horses was significantly (P < 0.05) greater than the activity in the large colon of group-2 horses. Decreased apparent digestion of phosphorus and a negative phosphorus balance are persistent features of large-colon resection in horses. Increases in alkaline phosphatase activity in the remaining colon of horses with extensive large-colon resection may be a specific functional adaptive mechanism that attempts to counteract the derangements in phosphorus metabolism.
Immunologic factors related to survival and performance in neonatal swine
Authors: Tyler Jeff W. , Cullor James S. , Thurmond Mark C. , Douglas Vicki L. , Parker Kent M.
Published: January 2024

Logistic regression was used to develop models predicting preweaning survival in 334 neonatal swine. Measured risk factors included birth weight, litter size (live born), dam parity, serum IgG concentration, serum elisa titers recognizing common gram-negative core antigens, and serum concentrations of the third component of complement. Larger birth weights were associated with increased probability of preweaning survival. The highest mortality was observed in litters with more than 12 pigs. Pigs with serum concentration of the third component of complement (C3) in the lowest stratum, < 20% adult pooled C3 standard (APC3), had reduced mortality, compared with high (> 38% APC3) and middle (20 to 38% APC3) groups. Associations between all other variables, including total serum IgG concentration and preweaning survival were not significant. Few pigs had hypogammaglobulinemia, < 3% of the study population had serum IgG concentrations < 1 g/dl. Of all measured variables, only birth weight and dam parity were significant predictors of preweaning gain. Larger pigs and pigs born to third or greater parity dams had more preweaning gain than other pigs.
Maturation of spinal-evoked potentials to tibial and ulnar nerve stimulation in clinically normal dogs
Authors: Steiss Janet E. , Wright James C.
Published: January 2024

Spinal-evoked potentials were recorded from 2 litters of clinically normal mixed-breed dogs between 35 and 300 days of age. Summated responses to tibial nerve stimulation were recorded from percutaneous needle electrodes placed at L7-S1, L4-5, T13-L1, C7-T1, and the cisterna cerebellomedullaris. The ulnar nerve was stimulated with recordings at C7-T1 and the cisterna cerebellomedullaris. Amplitudes did not change significantly with age, but were significantly (P < 0.05) different between various recording sites. On day 35, segmental and overall (L7-cisterna cerebellomedullaris) conduction velocities were less than half of the adult values. Spinal cord conduction velocities increased with age, reaching adult values at approximately 9 months of age. It was determined that quadratic equations best predicted the conduction velocities during maturation.
Postadulticide pulmonary hypertension of canine heartworm disease: Successful treatment with oxygen and failure of antihistamines
Authors: Rawlings Clarence A. , Tackett Randall L.
Published: January 2024

Postadulticide pulmonary hypertension mechanisms and treatment with antihistamines and supplemental oxygen were studied in eight dogs with heartworm disease. To ensure severe postadulticide thromboembolism, additional heartworms (either 20 or 40 into 4 dogs each) were transplanted into naturally infected dogs before thiacetarsamide treatment. During pentobarbital anesthesia, 2 pulmonary hemodynamic studies were conducted on each dog with a sequence of baseline, hypoxia with FlO2 = 10%, hyperoxia with FlO2 = 100%, a second baseline, treatment with either diphenhydramine (D) or cimetidine (C), and another hypoxia.

All dogs were pulmonary hypertensive, with each dog having a mean pulmonary arterial pressure (PPA) > 20 mm of Hg. Mean PPA increased from baseline conditions (25.0 ± 4.5 SD for D and 24.3 ± 4.4 for C) to hypoxia (28.5 ± 4.7 for D and 28.4 ± 3.7 for C), and decreased during hyperoxia (16.9 ± 3.0 for D and 17.4 ± 3.0 for C), respectively. Neither antihistamine reduced PPA at normoxia. The degree of pulmonary hypertension when breathing room air increased even more during hypoxia, and this increase was not attenuated by either antihistamine. Histamine did not appear to mediate pulmonary hypertension during postadulticide thromboembolism, nor to modify the hypoxia-mediated pulmonary hypertension at this disease stage. Because baseline PO2 was low (66.6 ± 11.7 mm of Hg for D and 69.4 ± 14.2 for C) and because PPA decreased during administration of oxygen, the pulmonary hypertension was mostly hypoxia-induced. In addition to the arterial lesions, much of the pulmonary hypertensive mechanism was an active and reversible vasoconstriction in response to hypoxia caused by the secondary lung disease. Supplemental oxygen to dogs with pulmonary hypertension could reduce PPA and right ventricular afterload. This study supports the use of oxygen, but not antihistamine drugs, in the treatment of postadulticide heartworm disease in dogs that are hypoxic, with signs of congestive heart failure or dyspnea.
Effects of cyclophosphamide in newly hatched chickens after inoculation with avian nephritis virus
Authors: Narita Minoru , Kawamura Hitoshi , Furuta Kenji , Shirai Junsuke , Nakamura Kikuyasu
Published: January 2024

Effects of immunosuppression were compared in newly hatched chickens given cyclophosphamide (cy) after inoculation with avian nephritis virus (anv). All cy-treated infected chickens died within 13 days after inoculation of the virus and had heavy urate deposits throughout the body. However, non-cy-treated infected, cy-treated noninfected, and non-cy-treated noninfected control chickens survived through the observation period. In a chronologic study, the value of serum uric acid in cy-treated infected chickens was more than 3 times higher than that in non-cy-treated infected chickens, and more than 9 times higher than in noninfected chickens. Serum uric acid values were coincident with the positive degree of anv antigen in the tubular epithelial cells in the kidneys and with the severity of renal degeneration. Serologic and immunohistologic examinations did not reveal detectable antibody and IgG- and IgM-containing cells in the spleen and kidneys of cy-treated infected chickens. However, non-cy-treated infected chickens had an increased number of IgM- and IgG-containing cells and antibody against anv on postinoculation day 6. These findings demonstrated that cy treatment enhanced the susceptibility of chickens to anv infection.
Effect of gentamicin administration on the neuromuscular blockade induced by atracurium in cats
Authors: Forsyth Sandra F. , Ilkiw Jan E. , Hildebrand Susan V.
Published: January 2024

Atracurium besylate, a nondepolarizing neuromuscular blocking agent, was administered as an infusion to 8 anesthetized cats in which neuromuscular blockade was assessed, using the train-of-four response. Once 50% depression of the first-twitch (T1) response was achieved, the infusion was held constant for 60 minutes before being discontinued and the recovery time was determined. The time for recovery was recorded as the time for the train-of-four ratio (T4 ratio) to increase from 50% to 75%. After-recovery, atracurium infusion was reinstituted and the cats were again maintained for 60 minutes at 50% depression. A single bolus of gentamicin sulfate (2.0 mg/kg of body weight) was administered iv, and the infusion was continued for another 60 minutes before it was discontinued and the time for recovery was recorded.

Within 1 minute of gentamicin administration, the mean ± SD T1 response decreased from 49 ± 5% to 33 ± 8% of baseline and the T4 ratio decreased from 28 ± 19% to 14 ± 11%. Peak effect occurred at 5 minutes, with a T1 response of 29 ± 6% of baseline and a T4 ratio of 13 ± 12%. By 60 minutes after gentamicin administration, the T1 response had increased to 38 ± 7% of baseline and the T4 ratio had increased to 21 ± 13%. The time for recovery significantly (P < 0.03) increased from 9.9 ± 3.4 minutes during the control study to 18.1 ± 10.7 minutes during the gentamicin study.

In this study, gentamicin potentiated the neuromuscular blockade induced by atracurium and increased the recovery time. Residual blockade, observed after gentamicin administration was reversed with edrophonium.
Method for obtaining bovine zygotes produced in vivo
Authors: Ellington Joanna E. , Farrell Paul B. , Simkin Michael E. , Foote Robert H.
Published: January 2024

A superovulatory and surgical protocol was developed for recovery of bovine zygotes. Holstein cows and heifers were given follicle-stimulating hormone and cloprostenol to induce superovulation. Surgical cannulation and lavage of the uterine tube was performed 40 to 48 hours after the start of standing estrus. In general, cows had more corpora hemorrhagica than did heifers, but a higher percentage (P < 0.05) of ova recovered from cows were infertile. Several heifers were subjected to the procedure twice, and embryo recovery rates were equivalent both times.
Plasma hormone concentrations after administration of dexamethasone during the middle of the luteal phase in cows
Authors: Vighio Ghulam H. , Liptrap Robert M.
Published: January 2024

The effect of glucocorticoids on gonadal steroid and gonadotropic hormone concentrations and subsequent follicular activity in cows undergoing normal estrous cycles was evaluated by administration of dexamethasone (DXM) during the middle of the luteal phase. Seven cows were given physiologic saline solution twice daily from day 13 to day 17 of the estrous cycle (control experiment). During the next estrous cycle, cows were administered dxm (2 mg, im) twice daily on days 13 through 17. Plasma specimens obtained twice daily throughout the control and dxm-treatment cycles were assayed for progesterone and estradiol concentrations. The appearance of estrus after dxm treatment was delayed until days 23 to 25 in 3 cows and was not seen by day 35 in the other 4 cows, compared with mean (± sd) cycle length of 22.4 ± 3.2 in cows during the control experiment. Progesterone concentration remained significantly (P < 0.01) high on days 19 to 23, whereas estradiol values failed to increase (P < 0.05) on days 19 and 20 after treatment with dxm.

Blood samples were obtained at 15-minute intervals for 12 hours to compare (by analysis of covariance) the effect of dxm treatment on plasma hormone concentrations on day 15 of each cycle with those of day 10. Compared with values during the control experiment, a significant (P < 0.05) decrease was observed in the size of the pulses of luteinizing hormone (lh) and estradiol, although the number of pulses of each hormone per 12 hours was not affected when cows were given dxm. Baseline concentrations of lh and estradiol were not altered by type of treatment. Change in variables describing progesterone secretion was not seen. Results indicate that high glucocorticoid concentrations in the middle of the cycle may delay the onset of the next estrus. This delay appears to be attributable to prolonged luteal activity that may be associated with reduction in pulsatile estradiol secretion as a consequence of suppressed lh concentration in the middle of the cycle.
Modified transvenous endomyocardial biopsy technique in dogs
Authors: Keene Bruce W. , Kittleson Mark E. , Atkins Clarke E. , Rush John E. , Eicker Steven W. , Pion Paul , Regitz Vera
Published: January 2024

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in healthy dogs and dogs with dilated cardiomyopathy positioned in lateral recumbency. This technique allowed acquisition of multiple biopsy specimens from the right ventricle of each of 22 hemodynamically normal dogs and 40 of 42 dogs with congestive heart failure. In 2 dogs with dilated cardiomyopathy, transvenous access to the right ventricle could not be achieved, but left ventricular biopsy was performed without complication. Complications were infrequent, and dogs recovered to at least their baseline status within 48 hours. Evaluation of the efficacy and complication rate of the procedure with each of the 2 biopsy instruments currently available identified no differences between them.
Correlation of brain stem auditory-evoked responses with cranium size and body weight of dogs
Authors: Pook Harold. A. , Steiss Janet E.
Published: January 2024

Brain stem auditory-evoked responses were recorded in 9 male and 11 female clinically normal mature dogs, weighing between 2 and 36 kg. Mean wave latency for the entire group of dogs, using 60-dB hearing level click stimuli at 11/s for waves I to VII was: 1.41, 2.21, 2.85, 3.31, 3.71, 5.12, and 6.46 ms, respectively. The mean interpeak latency for waves I and V (ipliv) was 2.32 ms. Neither gender nor ear effect was detectable.

Positive correlation was observed between cranium length, cranium width, nasion-external auditory meatus interval, and body weight for wave-V latency and ipliv. Such correlation was not documented for wave I. The regression equations for their effects on ipliv were: cranium length, y = 0.05x + 1.85; cranium width, y = 0.07x + 1.32; nasion-external auditory meatus interval, y = 0.05x + 1.79; and body weight, y = 0.01x + 2.15. On the basis of any of the 3 variables of cranium size or body weight, the study population could be classified into groups of large and small dogs, with the large group having significantly (P < 0.05) longer latency for wave V and ipliv. It is recommended that the effect of size variation in dogs on brain stem auditory-evoked responses should be compensated for by use of the regression equation based on cranium length.
Atypical cilia in the oviductal epithelium of healthy prepubertal gilts
Authors: Roperto F. , Galati P. , Papparella S. , Campofreda M. , Rossacco P.
Published: January 2024

Specimens of the uterine tube epithelium (ampulla) were obtained from 20 healthy, prepubertal, ovariohysterectomized gilts. A 2 to 3% proportion of atypical cilia was observed. Of 6,600 transversely sectioned cilia, 122 (1.8%) had microtubular disorganization, whereas 444 of 48,080 totally examined cilia (0.9%) were compound, 104 (0.2%) were swollen, and 44 (0.09%) were intracytoplasmic.
Effect of sodium bicarbonate infusion on serum osmolality, electrolyte concentrations, and blood gas tensions in cats
Authors: Chew Dennis J. , Leonard Mark , Muir William W.
Published: January 2024

The effects of single iv injections of sodium bicarbonate (0.5 mEq/kg of body weight, 1 mEq/kg, 2 mEq/kg, and 4 mEq/kg) on serum osmolality, serum sodium, chloride, and potassium concentrations, and venous blood gas tensions in 6 healthy cats were monitored for 180 minutes.

Serum osmolality increased and remained significantly (P < 0.05) increased for 120 minutes in cats given 4 mEq of sodium bicarbonate/kg. Serum sodium was increased significantly (P < 0.05) for 30 minutes in cats given 4 mEq of sodium bicarbonate/kg. Serum sodium decreased and remained significantly (P < 0.05) decreased for 120 minutes in cats given 1 g of 20% mannitol/kg, and serum osmolality was significantly (P < 0.05) decreased at 30 and 60 minutes. Serum chloride decreased significantly (P < 0.05) for 10 minutes in cats given 1 mEq of sodium bicarbonate/kg, and was significantly decreased for 30 minutes in cats given 2 mEq and 4 mEq of sodium bicarbonate/kg. Serum chloride decreased and remained significantly (P < 0.05) decreased for 30 minutes in cats given 1 g of 20% mannitol/kg. Serum sodium and serum osmolality did not change significantly (P < 0.05) in cats given 4 ml of 0.9% sodium chloride/kg.

Serum potassium decreased significantly (P < 0.05) for 10 minutes in cats given 1 mEq of sodium bicarbonate/kg, and for 120 minutes in cats given 2 mEq/kg or 4 mEq/kg. There was a significantly (P < 0.05) greater decrease in serum potassium that lasted for 30 minutes after giving sodium bicarbonate at the dosage of 4 mEq/kg, compared with other dosages given. Serum potassium did not change significantly in cats given 1 g of 20% mannitol/kg, but was significantly (P < 0.05) decreased 10 minutes following 4 ml of 0.9% sodium chloride/kg.

Sodium bicarbonate infusion significantly (P < 0.05) increased venous blood pH and plasma bicarbonate concentration in all cats. The magnitude and duration of these changes were significantly greater following administration of sodium bicarbonate at dosages of 2 mEq/kg and 4 mEq/kg. Significant (P < 0.05) increases in Pco2 were associated only with the highest dosage of sodium bicarbonate (4 mEq/kg). Base excess increased significantly (P < 0.05) in all cats following sodium bicarbonate infusion. There were significantly (P < 0.05) greater increases in base excess lasting 30 minutes following administration of sodium bicarbonate at dosages of 2 mEq/kg and 4 mEq/kg. Significant (P < 0.05) changes in venous blood pH, Pco2, or bicarbonate were not observed in cats given 4 ml of 0.9% sodium chloride/kg, or in cats given 1 g of 20% mannitol/kg. Base excess was significantly (P < 0.05) increased for 10 minutes in cats given 1 g of 20% mannitol/kg.

As expected, 4 mEq of sodium bicarbonate/kg induced the most time- and dosage-related effects. Caution should be used when administering sodium bicarbonate iv to cats at dosages > 2 mEq/kg, because of the potential for important acid-base and electrolyte changes.
Pudendal reflexes and effects of conditioning stimuli in cats
Authors: Cook James R. , Oliver John E. , Purinton Paul T.
Published: January 2024

Evaluation of pudendal reflexes and effects of pudendal branch conditioning on those reflexes was carried out in 2 studies. In the first study of pudendal reflexes, 20 adult male and female mixed-breed cats underwent surgical isolation of the anal branch, urethral branch, and distal trunk (consisting primarily of the dorsal nerve of the penis/clitoris) of the pudendal nerve. Reflexes were tested in all possible ipsilateral and contralateral test-response combinations. Latency values and effects of increasing stimulus rate on response amplitude were recorded. Reflexes were detected in all combinations, with response latencies between 6.3 and 13.0 ms. Response amplitudes were diminished at stimulus rates of 3 to 5 Hz, and responses were apparently abolished at 4 to 16 Hz, suggesting that pudendal reflexes are polysynaptic.

In the second study of conditioning effects, 9 adult male and female mixed-breed cats underwent preparation similar to that for study 1. A train of conditioning stimuli was applied to branches of the pudendal nerve prior to attempting to induce reflex responses, as performed in study 1. Conditioning completely abolished reflex responses for a period of 70 to 130 ms. Reflex responses were diminished in amplitude, compared with those observed during preconditioning trials, for 180 to 300 ms after conditioning.
Seroprevalence of ovine progressive pneumonia virus in various domestic and wild animal species, and species susceptibility to the virus
Authors: Cutlip Randall C. , Lehmkuhl Howard D. , Brogden Kim A. , Schmerr Mary Jo F.
Published: January 2024

Ovine progressive pneumonia is caused by a lentivirus of known infectivity only for sheep and goats. Virus susceptibility of 11 other species of animals was examined. Species included cattle, chickens, deer, dogs, goats, hamsters, horses, mice, pigs, rabbits, and rats. Of these species, only goats and rabbits could be experimentally infected with the virus. The infection in rabbits was acute, and virus did not persist or induce antibody production as it does in sheep and goats. Sera obtained from several people working in close contact with the virus and from several wild species, with unknown exposure history, were tested for antibodies to viral antigens. All results were negative. Knowledge of the host range of this virus is important for scientific studies and for virus eradication programs.
Effects of flunixin meglumine on endotoxin-induced prostaglandin F2α secretion during early pregnancy in mares
Authors: Daels Peter F. , Stabenfeldt George H. , Hughes John P. , Odensvik Kristina , Kindahl Hans
Published: January 2024

The role of prostaglandin F2α (pgf2α) in embryonic loss following induced endotoxemia was studied in mares that were 21 to 44 days pregnant. Thirteen pregnant mares were treated with a nonsteroidal anti-inflammatory drug, flunixin meglumine, to inhibit the synthesis of pgf2α caused by Salmonella typhimurium endotoxin given iv. Flunixin meglumine was administered either before injection of the endotoxin (group 1, -10 min; n = 7), or after endotoxin injection into the mares (group 2, 1 hour, n = 3; group 3, 2 hours, n = 3); 12 pregnant mares (group 4) were given only S typhimurium endotoxin.

In group 4, the secretion of pgf2α, as determined by plasma 15-keto-13,14-dihydro-pgf2α concentrations, was biphasic, initially peaking at 30 minutes followed by a second, larger peak approximately 105 minutes after the endotoxin was given iv. When flunixin meglumine was administered at −10 minutes, synthesis of pgf2α was inhibited for several hours, after administration of flunixin meglumine at 1 hour, the second secretory surge of pgf2α was blocked, and administration of the drug at 2 hours did not substantially modify the secretion of pgf2α.

Plasma progesterone concentrations were unchanged after endotoxin injections were given in group 1. In group 2, progesterone values decreased < 2 ng/ml and remained low for several days. In group 3 and group 4, progesterone concentrations decreased to values < 0.5 ng/ml by 48 hours after endotoxin injections were given. Pregnancy continued in all 7 mares in group 1; in group 2, pregnancy continued in 2 of 3 mares; and in group 3, none of the 3 mares was pregnant by 4 days after endotoxin administration.

The abortifacient effect of endotoxemia in mares < 2 months pregnant is mediated indirectly through the secretion of pgf2α; compromised luteal activity and inadequate progesterone secretion are the primary causes of fetal death. Although flunixin meglumine administration can be used to prevent loss of pregnancy in cases of endotoxemia, it must be initiated at an early stage of the endotoxemia, that is, when clinical signs are often not yet apparent.
Pharmacologie enhancement or suppression of phagocytosis by bovine neutrophils
Authors: Paape Max J. , Miller Robert H. , Ziv Gideon
Published: January 2024

Sixty-three drugs, belonging to 10 chemical classes, were tested in vitro to determine effects on phagocytosis of 32P-labeled Staphylococcus aureus by neutrophils isolated from milk. Within each class, the number of antibiotics tested were: nonsteroidal anti-inflammatory drugs (nsaid; 8), peptolids (2), aminoglycosides (8), tetracyclines and fusidic acid (4), β-lactam antibiotics (25), secretolytic agents (2), macrolides (5), polypeptides (2), and antibacterial quinolones (8). Percentage of phagocytosis was determined after incubating (2 hours at 37 C) 12.5 × 106 viable neutrophils, 200 × 106 32P-labeled S aureus with antibiotics and 5% skimmed milk. Concentrations of antibiotics tested were 1,000, 500, and 10 μg/ml of incubation media. When compared with nonantibiotic controls at the highest drug concentration, the nsaid acetylsalicylic acid and centrophenoxine increased phagocytosis 23.2 and 8.8%, respectively, and benzydamine, indomethacin, phenylbutazone, ibuprofen, and acetominophen decreased phagocytosis 22.8, 14.2, 9.8, 27.0, and 18.2%, respectively. The peptolids novobiocin and pristinamycin decreased phagocytosis 24.5 and 22.0%, respectively. The aminoglycosides tobramycin, amikacin, and gentamicin decreased phagocytosis 21.1, 15.4, and 19.2%, respectively. For the tetracyclines and fusidic acid, minocycline and doxycycline decreased phagocytosis 39.8 and 54.2%, respectively. The β-lactam antibiotics carfecillin, cephapirin sodium, and cephacetrile sodium decreased phagocytosis 11.2, 12.8, and 23.8%, respectively. The secretolytic agent, bromhexin, increased phagocytosis 10.8%. These data indicate that the potential for enhanced phagocytosis exists through use of some nsaid, and for depressed phagocytosis through use of aminoglycosides, peptolids, tetracyclines, and beta-lactams, as well as certain other nsaid.
Effects of α-ketoisocaproate on adrenocorticotropin-induced suppression of lymphocyte function in sheep
Authors: Kuhlman Gail , Roth James A. , Nissen Steven
Published: January 2024

Previous studies of the amino acid analogue, α-ketoisocaproate (kjc), indicate that it can stimulate lymphocyte blastogenesis and antibody responses of sheep. To determine whether kic could overcome the effects of adrenocorticotropic hormone (acth)-induced lymphocyte suppression, 24 lambs were fed a control diet, a diet supplemented with 0.05% kic, or a diet supplemented with 0.05% of the parent amino acid leucine. Immune status was monitored by determining lymphocyte blastogenic responsiveness to phytohemagglutinin-P (pha), concanavalin A (conA), and pokeweed mitogen (pwm) and percentages of T-cell subsets in the blood, using monoclonal antibodies and a flow cytometer. Serum Cortisol, insulin, and glucagon concentrations also were determined. After 60 days of consuming the respective diet, lambs were administered either saline solution or acth (100 IU) twice daily for 3 consecutive days. Administration of acth increased serum cortisol and insulin concentrations; however, no effects were seen for serum glucagon concentration. Compared with saline administration, acth administration significantly (P < 0.05) suppressed mitogen-stimulated lymphocyte blastogenesis by approximately 50%, regardless of the mitogen used, and significantly (P < 0.01) decreased the percentage of circulating T lymphocytes and decreased (P < 0.01) the ratio of T4 to T8 cells. Lambs fed kic had greater pha- and conA-stimulated blastogenic responses and significantly (P < 0.05) increased ratio of T4 to T8 cells in the blood, compared with lambs fed the leucine-supplemented diet or the control diet and given corresponding injections. These data indicate that acth decreased in vitro lymphocyte blastogenesis and altered the subset ratios of blood lymphocytes in sheep. These changes were partially prevented by feeding kic.
Effect of ivermectin on the immune response in mice
Authors: Blakley B. R. , Rousseaux C. G.
Published: January 2024

To assess the effect of ivermectin on immune function (antibody production), male CD-1 mice were inoculated with an antigen the day after sc administration of ivermectin (0.2 mg/kg of body weight or 20 mg/kg). Responses were evaluated 5 days after inoculation of the antigen. Antibody production against sheep rbc, a T lymphocyte-, macrophage-dependent response, was enhanced by ivermectin treatment (P = 0.00049). In contrast, antibody production against dinitrophenyl-Ficoll, a T lymphocyte independent, macrophage-dependent response, was not altered by ivermectin treatment. Results indicate that the immunostimulatory properties of ivermectin are associated with altered function of T lymphocytes, in particular, T-helper lymphocytes. The immunomodulating effects of ivermectin may provide an alternative approach for treatment of disease problems involving immunosuppression.
Colonization control of lactose-fermenting Salmonella typhimurium in young broiler chickens by use of dietary lactose
Authors: Ziprin Richard L. , Elissalde Marcel H. , Hinton Arthur , Beier Ross C. , Spates George E. , Corrier Donald E. , Benoit Thomas G. , DeLoach John R.
Published: January 2024

Inclusion of lactose in the diets of chickens has been determined to reduce cecal colonization with Salmonella typhimurium. We hypothesized, therefore, that dietary lactose may be a practical means for reducing the prevalence of Salmonella contamination of chicken products. Because some strains of Salmonella are atypical and ferment lactose, we investigated the effects of dietary lactose on cecal colonization with lactose-fermenting S typhimurium. Broiler chicks were inoculated intracloacally with Lac+ S typhimurium selected for resistance to novobiocin and rifampicin. The chicks also were inoculated orally with certain anaerobes that do not effectively inhibit colonization by S typhimurium, but do appear essential for lactose mediated inhibition of cecal colonization. Control chicks were not given dietary lactose, and chicks in the experimental group were fed a diet containing 7% lactose. Enumeration of Lac+ S typhimurium in cecal contents revealed dietary lactose to be effective at controlling this organism. Control was correlated with changes in cecal pH and increases in undissociated volatile fatty acids, especially propionic acid.
Serum glucose and insulin responses to an insulin-containing ophthalmic solution administered topically in clinically normal cats
Authors: Hopper Patrick E. , Murphy Christopher J. , Feldman Edward C. , Nelson Richard W. , Bottoms G. D. , Franti Charles E.
Published: January 2024

Serum glucose and immunoreactive insulin concentrations were monitored after topical administration of an insulin-containing ophthalmic solution in 20 clinically normal cats. Three ophthalmic surface-acting agents, benzalkonium chloride, dimethyl sulfoxide, and proparacaine hydrochloride, were evaluated individually for their effectiveness in enhancing absorption of topically applied insulin. The ophthalmic effects of insulin-containing ophthalmic preparations were assessed by complete ophthalmic examination before and at the conclusion of each test period. Withholding of food overnight (12 hours) preceded each topical application of insulin-containing ophthalmic solution (12.25 to 26.4 U/cat), either alone or in combination with surface-acting agents, after which blood samples were drawn serially from an indwelling iv catheter over a period of 8 hours. Baseline serum insulin concentration, after food was withheld for 12 hours, in nonstressed cats was 6.0 μU/ml (geometric mean), and an exponentiation of the logarithmic quantity (mean ± sd) yielded values of 1.5 to 23.0 μU/ml. All ophthalmic solutions tested failed to significantly lower serum glucose concentration or increase serum insulin concentration. Solutions used did not induce deleterious effect on ocular structures. Results indicate that topical administration of insulin-containing ophthalmic solution, either alone at the concentrations used or in combination with surfaceacting agents, did not result in effective absorption of insulin across the conjunctival and lacrimal nasal mucosa in biologically relevent quantities. Thus, this route of insulin administration, under these specific conditions, is not an effective alternative or adjunct to SC administration of insulin for treatment of cats with insulin-dependent diabetes mellitus or severe noninsulin-dependent diabetes mellitus.
Serially determined plasma α-tocopherol concentrations and results of the oral vitamin E absorption test in clinically normal horses and in horses with degenerative myeloencephalopathy
Authors: Blythe L. L. , Craig A. M. , Lassen E. D. , Rowe K. E. , Appell L. H.
Published: January 2024

Plasma α-tocopherol (vitamin E) values were monitored serially in 9 foals sired by a stallion with equine degenerative myeloencephalopathy (EDM) and in 5 agematched control foals (sired by a clinically normal stallion) raised in the same environment for the first year of life. Clinical evaluation determined that 8 of the 9 foals sired by the stallion with EDM had neurologic deficits consistent with the disease on one or more occasions during the study period, whereas control foals had normal gait. From 6 weeks to 10 months of age, plasma α-tocopherol values in foals with signs of EDM were significantly (P < 0.001) lower than those in control foals. An oral vitamin E absorption test was performed, and results for 8 of the affected horses and the affected stallion were compared with results for 4 of the monitored control horses and 4 additional control horses. Significant differences were not evident in any of the absorption indices. On the basis of data from this study and supported by reported prophylactic and therapeutic benefits of supplemented vitamin E, low plasma concentration of vitamin E is concluded to be a factor in the development of EDM in the first year of life of hereditarily predisposed foals. It was also concluded that the significantly lower α-tocopherol values seen in the foals in this study did not reflect a primary gastrointestinal tract absorption problem.