bluuebunny/crossref_metadata_2025 huggingface dataset:
Erythrocyte characteristics in vitamin E-responsive anemia of the owl monkey (Aotus trivirgatus)
Authors: Brady P. S. , Sehgal P. K. , Hayes K. C.
Published: February 2025

To characterize the vitamin E-responsive anemia occurring in owl monkeys (Aotus trivirgatus), osmotic fragility, and H2O2-induced and time-dependent hemolysis, as well as rbc lipid peroxidation, were compared in anemic and nonanemic owl monkeys. Whereas vitamin E serves as a lipid-soluble antioxidant, the glutathione peroxidase system functions in the water-soluble phase of the cell. Thus, activity of glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase, as well as reduced glutathione concentrations in owl monkeys’ rbc, were compared with those of rhesus macaques and cebus and squirrel monkeys fed the same diet and maintained under the same management scheme. Osmotic fragility did not differ between anemic and nonanemic owl monkeys. The H2O2-induced and time-dependent hemolysis was approximately 10-fold greater among anemic owl monkeys than among their nonanemic counterparts, and lipid peroxidation values tended to be higher in the anemic monkeys. Owl monkeys, as a species and independent of anemia, exhibited higher rbc peroxidation than did 2 other New World species, cebus and squirrel monkeys. The glutathione peroxidase system was not depressed in owl monkey rbc. The only observed difference in this system was in the glucose-6-phosphate dehydrogenase activity, which was 3- to 6-fold higher in the owl monkey than in the other species, indicating an increased activity of the peroxidase system. Thus, a defect in the glutathione peroxidase system could not be identified.
Effect of berberine on intestinal secretion mediated by Escherichia coli heat-stable enterotoxin in jejunum of pigs
Authors: Zhu Beilei , Ahrens Franklin A.
Published: February 2025

Intraluminal perfusion with Escherichia coli heat-stable enterotoxin (st) reversed water and electrolyte movements from net absorption to net secretion in porcine jejunal segments. Addition of berberine hydrochloride (3.2 × 10−5M) to the perfusate reduced the jejunal secretory response of water, sodium, potassium, and chloride to st and enhanced water and electrolyte absorption in control segments. At lower concentrations (1.1 × 10−5M), berberine reduced the secretory response in st-exposed segments, but only the decrease of sodium flux was significant. In the presence of berberine, the mucosal enzyme activities of adenosine triphosphatase and disaccharidases were not significantly different between control and st-exposed segments.

Doses of 1,2,3,4, 5, and 10 mg of berberine were injected into ligated loops of proximal part of the jejunum with 1 ml of st filtrate. At doses of 2 or more mg/loop, berberine was effective in reducing water and electrolyte secretions induced by st; the effect was dose-dependent. These findings indicate that berberine may be an effective antidiarrheal agent in E coli heat-stable enterotoxin mediated secretory diarrhea and provide a basis for the frequent empirical use of berberine alkaloid and berberine-containing plants in gastroenteritis and infectious diarrhea in Asian and other countries.
α-Difluoromethylornithine: A promising lead for preventive chemotherapy for coccidiosis
Authors: Hanson William L. , Bradford Marion M. , Chapman Willie L. , Waits Virginia B. , McCann Peter P. , Sjoerdsma Albert
Published: February 2025

α-Difluoromethylornithine (dfmo; RMI 71,782) given in drinking water in concentrations as low as 0.0625% inhibited infections of Eimeria tenella and minimized the development of lesions in chickens. It had approximately the same activity as a currently used anticoccidial drug, amprolium, and also had the advantage of being relatively nontoxic in chickens. Body weight gains were not reduced in chickens given 0.0625% dfmo or less for 14 days starting 8 days before they were inoculated with oocysts, but were reduced in chickens given drinking water containing 0.125 and 0.25% dfmo. The anticoccidial activity of dfmo was completely reversed by injection (intraabdominal) of putrescine hydrochloride (300 mg/kg of body weight/day), indicating that the drug may act by blocking putrescine biosynthesis. Inoculated chickens, in which coccidial lesion development was suppressed by dfmo, resisted subsequent challenge exposure with E tenella, as did nontreated infected control birds which had recovered from infection.
Pharmacodynamic and pharmacokinetic properties of diazepam in horses
Authors: Muir W. W. , Sams R. A. , Huffman R. H. , Noonan J. S.
Published: February 2025

The cardiopulmonary, behavioral, and pharmacokinetic properties of diazepam were determined in horses. Heart rate, cardiac output, mean pulmonary artery, aortic and right atrial blood pressures, respiratory rate, and arterial pH and blood gas values did not change after iv diazepam (0.05, 0.1, 0.2, 0.4 mg/kg) administration. Increasing doses of diazepam resulted in signs of muscle weakness including fixed stance, muscle fasciculations of the head, neck, and thorax muscles, ataxia, and then recumbency. Dosages of diazepam exceeding 0.2 mg/kg produced mild sedation. Behavioral changes persisted for up to 2 hours with a dosage of 0.4 mg/kg.

Plasma concentration-time data in horses given brief (5 min) infusions of diazepam were described by a triexponential equation. Total body clearances of diazepam were between 6.94 and 9.56 ml/min/kg, and the half-life values between 2.52 and 21.6 hours. The volume of distribution at steady state was 1.56 to 2.94 L/kg.

N-Desmethyldiazepam was identified by gas chromatography-mass spectrometry following glucuronide hydrolysis of urine. Oxazepam, N-methyloxazepam, and N-desmethyl-diazepam, but not diazepam, were detected after glucuronide hydrolysis of urine collected from 1 horse which was given 140 mg of iv diazepam. Only N-desmethyldiazepam was detected in hydrolyzed urine samples collected from other horses given 80 mg of diazepam.
Bovine herpesvirus-1 vaccination against experimental bovine herpesvirus-1 and Pasteurella haemolytica respiratory tract infection: Onset of protection
Authors: Jericho K. W. F. , Yates W. D. G. , Babiuk L. A.
Published: February 2025

The onset of protection offered by intranasal vaccination with attenuated bovine herpesvirus-1 (bhv-1) was studied in 18 calves given a virulent bhv-1 aerosol challenge inoculum and an aerosol challenge exposure to Pasteurella haemolytica. Calves challenge exposed with virus 3, 7, 11, 15, or 19 days after vaccination and challenge exposed 4 days later with Pasteurella haemolytica did not develop viral-bacterial pneumonia, whereas 2 of 3 control calves died of fibrinous bronchopneumonia 40 and 60 hours after the bacterial aerosol and the 3rd control calf had similar lesions. All vaccinated and control calves had detectable amounts of interferon at the time of viral challenge exposure. Protection was observed before detection of neutralizing antibodies to bhv-1 in nasal secretions or in serum. Protection was therefore present from day 3 through day 19 after vaccination, but the mechanism could not be explained completely by neutralizing antibody or interferon.
Immunoperoxidase labeling of canine distemper virus replication cycle in Vero cells
Authors: Higgins R. J. , Krakowka S. , Metzler A. E. , Koestner A.
Published: February 2025

An indirect immunocytochemical labeling technique, using horseradish peroxidase-conjugated antibody was used to detect the intracellular and surface membrane localization of canine distemper virus (R252-cdv) antigens during productive virus replication in infected Vero cells. Specific labeling of intracellular viral antigens was restricted to rough nucleocapsid aggregates. Surface membrane labeling correlated directly with the appearances both of virus-specific membrane spikes and buds and of mature virions. Syncytial cell formation was associated with labeled cytoplasmic nucleocapsid, but there was no evidence of productive cdv formation on surface membranes. The immunoperoxidase technique provided precise ultrastructural antigenic localization with concomitant preservation of excellent ultrastructural detail within single virus-infected cells during cdv replication cycle in vitro.
Effects of estrogen-progesterone implants on the blood coagulation system of lambs
Authors: Al-Baker J. , Keeton K. S.
Published: February 2025

Results of a study on the effects of estrogen-progesterone implants on the coagulation system in lambs indicated that fibrinogen concentration and factors II, VII, and IX activities were increased, whereas antithrombin III levels were lowered. The prothrombin time and activated partial thromboplastin time were decreased. These changes, together with the exaggerated response of platelet aggregation to adenosine diphosphate, identified the development of a hypercoagulable state in the lambs.
Isolation of equine neutrophils and analysis of functional characteristics by chemiluminescence and bactericidal assays
Authors: Jacobsen K. , Gintz T. , Reed S. M. , Newbry Jerry , Bayly W. M. , Perryman Lance E. , Leid R. Wes
Published: February 2025

Equine neutrophils (pmn) were isolated to > 99% purity by isopyknic sedimentation on coated colloidal silica particles. A cell recovery of 84.7 ± 4.0%, with a viability of > 99%, was observed with this method. The isolated pmn were compared with mixed population of equine peripheral leukocytes with respect to functional integrity by chemiluminescence and bactericidal assays. There was no significant difference (P < 0.01) observed in either assay between the isolated equine pmn and the mixed-cell populations. The methods used in both the isolation, as well as the functional characterization of the equine pmn, were rapid and highly reproducible and should readily find use in clinical and research laboratories. It is now feasible to rapidly assess equine pmn integrity in those cases which warrant this type of study. This is the first direct comparison of the chemiluminescence assay with the microbicidal assay, using equine pmn.
Reaction of normal equine eyes to radio-frequency current-induced hyperthermia
Authors: Neumann Sylvia M. , Kainer Robert A. , Severin Glenn A.
Published: February 2025

In the main study, hyperthermia was induced by radio-frequency current to obtain a single, central, corneal lesion in the right eye and 2 separate limbal lesions in the left eye of 13 light horses and 8 ponies. Intracorneal and intralimbal temperature profiles for the procedure were obtained in a separate study from the eyes of a horse and a pony treated in the same manner.

After treatment of the principal eyes and 6 sham-treated eyes, clinical observations were conducted for up to 6 months, using indirect ophthalmoscopy, biomicroscopy, and fluorescein staining. Immediately after hyperthermic treatment of the eyes, dense opaque imprints of the electrodes of the localized current field device were present. Ulcerative keratitis persisted variably from day 2 through day 6 after treatment; anterior uveitis was present from day 2 through day 7. A mucopurulent discharge occurred infrequently, and conjunctival hyperemia was variable. Depigmentation resulted from hyperthermic treatment at pigmented limbal sites. Small scars persisted at 1 central site and 6 limbal sites where the electrodes were positioned vertically. Vision was not compromised in any of the horses permitted to live beyond a week.

Microscopically, denudation and subsequent repair of the corneal epithelium correlated with the presence and then the absence of fluorescein staining. Stromal inflammation, edema, disorganization of collagenous fibers, and temporary disruption of corneal endothelium contributed to transitory corneal opacity. Time required for repair of corneal tissues varied, but all layers were integral 8 days after exposure to hyperthermia. Later changes included choroidal hydrops, vascular damage in conjunctival vessels, stromal neovascularization, and corneal fibroplasia.
Ultrastructure of the articular cartilage and synovium in the early stages of degenerative joint disease in canine hip joints
Authors: Greisen Helen A. , Summers Brian A. , Lust George
Published: February 2025

A combined light and electron microscopic study recorded the developing degenerative changes in the hip joints of dogs with spontaneous joint disease. Synovium from joints with normal articular cartilage contained 33% type A and 64% type B cells. The 1st evidence of articular cartilage degeneration was loss of the surface amorphous layer and disruption of collagen fibrils. In the face of the earliest focal cartilage defects, the number of type A cells decreased (P < 0.01) and remained low. Necrotic synoviocytes and synoviocytes of uncertain type increased as articular cartilage lesions progressed. The earliest pathologic changes in the synovium and the articular cartilage surface were evident only on ultrastructural examination.
Intravenous glucose tolerance test in cats: Influenced by acetylpromazine, ketamine, morphine, thiopental, and xylazine
Authors: Hsu Walter H. , Hembrough Frederick B.
Published: February 2025

Influences of chemical restraining agents of iv glucose tolerance test were studied in 3 cats. An iv injection of 0.5 g of glucose/kg produced hyperglycemia which was apparent at 15 minutes after the injection was done and disappeared at 45 minutes. All of the following drugs studied influenced the iv glucose tolerance test (0.5 g of glucose/kg): thiopental sodium (16 mg/kg, iv), ketamine (11 and 33 mg/kg, im), acetylpromazine (2.2 mg/kg, im), xylazine (2.2 mg/kg, im), and morphine (0.1 mg/kg, im). The results indicate that in cats glucose tolerance tests probably should be performed without chemical restraint. Data derived from tests where chemical restraint was used should be interpreted carefully, since the restraint drug, per se, may interfere with the test.
Pulmonary effects of intravenous histamine in the conscious pony: Dose-response relationships and reproducibility
Authors: Derksen F. J. , Slocombe R. F. , Robinson N. E.
Published: February 2025

In standing sedated ponies, we measured dynamic lung compliance (Cdyn) and pulmonary resistance (RL) during iv infusion of various doses of histamine; this was done in a given pony 3 times at 1-week intervals between experiments. Histamine doses causing a decrease in Cdyn of 50% and 75% and an increase in RL of 300% and 600% (ED50Cdyn, ED75Cdyn, ED300RL and ED600RL, respectively) were interpolated from the histamine dose-response curves. We also measured respiratory frequency, tidal volume, minute ventilation, functional residual capacity, arterial oxygen tension, arterial carbon dioxide tension, arterial pH, and mean systemic blood pressure before and after infusion of histamine sufficient to cause a decrease in Cdyn of at least 75% and at least a 600% increase in RL- Histamine decreased arterial oxygen tension and functional residual capacity, but did not alter arterial carbon dioxide tension, pH, respiratory frequency, tidal volume, minute ventilation, and mean arterial blood pressure. There was at least a 6-fold variability in ED50Cdyn, ED75Cdyn, ED300RL, and ED600RL between ponies, but these values were very reproducible for each individual. The ED50Cdyn, ED75Cdyn, ED300RL, and ED600RL all decreased with increasing age.
Antagonism of xylazine sedation by 4-aminopyridine and yohimbine in cattle
Authors: Kitzman Joseph V. , Booth Nicholas H. , Hatch Roger C. , Wallner Barbara
Published: February 2025

Twenty-four crossbred steers (4 groups of 6 steers each) were injected im with a standard dosage range of xylazine hydrochloride (0.2 to 0.3 mg/kg of body weight). When the steers were maximally sedated, group I (control group) were given isotonic saline solution (1 ml, iv), group II were given 4-aminopyridine (4-ap, 0.3 mg/kg) iv, group III were given yohimbine hydrochloride (0.125 mg/kg) iv, and group IV were given 4-ap (0.3 mg/kg) plus yohimbine hydrochloride (0.125 mg/kg) iv.

The 4-ap decreased mean standing time (mst; time until animal could stand unaided) from 94.3 minutes (control) to 13.4 minutes. Yohimbine decreased mst to 27 minutes. The combination of 4-ap + yohimbine decreased mst to 7.4 minutes. Mean total recovery time (mtrt; time from xylazine injection until normal behavior, including eating and drinking) was not significantly (P = > 0.05) decreased from control values by any of the antagonists tested.

The combination of 4-ap + yohimbine decreased mst in animals given a 3× overdose of xylazine (0.6 mg/kg) from 124 minutes (control) to 30.3 min. The mtrt was not significantly (P > 0.05) decreased from control values. Two animals given a 5× overdose of xylazine (1 mg/kg) and then given 4-ap + yohimbine had a mst of 32.5 minutes and a mtrt of 3.7 hours.

The combination of 4-ap + yohimbine produced marked antagonism of xylazine sedation in cattle. The combination of antagonists may prove to be useful for the arousal of animals sedated with xylazine alone or with a combination of sedatives including xylazine.
Recovery of pulmonary alveolar macrophages from nonanesthetized calves
Authors: Corstvet Richard E. , Rummage John A. , Homer John T.
Published: February 2025

A bronchopulmonary lavage technique is described for the recovery of pulmonary alveolar macrophages from nonanesthetized calves. The recovered fluid was shown to have between 106 and 107 macrophages for each 60 ml of volume infused. Of these, more than 95% were viable cells. Radiographically, it was shown that the site of recovery was a 4-mm airway.
New biological effect of edema disease principle Escherichia coli—neurotoxin) and its use as an in vitro assay for this toxin
Authors: Dobrescu Lucia
Published: February 2025

Edema disease principle (edp) extracted from porcine Escherichia coli strains was shown to be cytotoxic for Vero cells. This biological effect was thermolabile and specifically neutralized by anti-edp serum. The edp did not cross-neutralize with antiheat-labile enterotoxin or anti-Vero toxin sera. Parallel studies conducted in mice indicated that the same entity may be responsible for the in vivo and in vitro effects. The results of these experiments provide an effective basis for the first in vitro edp serologic test.
Thermographic evaluation of corticosteroid efficacy in amphotericin B-induced arthritis in ponies
Authors: Bowman K. F. , Purohit R. C. , Ganjam V. K. , Pechman R. D. , Vaughan J. T.
Published: February 2025

Thermographic evaluation of corticosteroid efficacy in amphotericin B-induced intercarpal and tibiotarsal arthritis was done in 12 ponies. Arthritis was induced in 8 joints by intra-articular injection of 10 mg of amphotericin B. Eight joints each were treated with intra-articular injection of 100 mg of methylprednisolone acetate before or after arthritis induction. AU joints were evaluated by physical examination, thermography, acid phosphatase activity in synovial fluid, radiography, and necropsy.

Intra-articular corticosteroid therapy, either before or after arthritis induction, was effective in alleviating the clinical signs of lameness in comparison with the clinical signs of nontreated arthritis. It was difficult to distinguish increased thermal patterns between corticosteroid-treated and nontreated joints on days 1 and 2 after arthritis induction; therefore, it was important to correlate the physical findings and distribution of increased heat patterns. There was no significant difference (P > 0.05) in the return to normal thermographic patterns between any treated intercarpal joints; corticosteroid therapy did not decrease the healing time of intercarpal arthritis. In contrast, corticosteroid therapy, before or after arthritis induction in the tibiotarsal joint, significantly decreased (P < 0.05) the time for return to normal thermographic patterns. This apparent difference between the intercarpal and tibiotarsal joints was not explained.

Acid phosphatase activity was highest and persisted longest in the synovial fluid of nontreated induced arthritis.

Radiographic evidence of osteoarthritis was found in 3 of 8 nontreated cases of induced arthritis. Production of osteoarthritic changes by induced synovial inflammation supports previous evidence that chronic arthritis without articular fracture may cause degenerative joint disease in the equine species.

Thermography was useful in detecting inflammation in the absence of clinical signs and aided the evaluation of the healing processes in amphotericin B-induced arthritis.
Congestive cardiomyopathy induced in ducklings fed graded amounts of furazolidone
Authors: Van Vleet John F. , Ferrans Victor J.
Published: February 2025

Newly hatched male White Pekin ducklings (n = 119) were allotted to 7 groups of 17 each and fed furazolidone (fz) at dose levels of 0. 100, 250, 500, 750, 1,000, and 1,250 mg/kg of feed for 4 weeks. The frequency and severity of clinical signs of fz toxicosis, including growth retardation, ascites, and mortality, were dose related. At necropsy, the affected ducklings had ascites, hydropericardium, and biventricular dilatation. The frequencies of cardiomyopathy, ascites, and mortality, respectively, for the several dose levels of drug were as follows: 0, 100, and 250 mg of fz/kg of feed—0%, 0%, 0%; for the 500 mg/kg level—35%, 12%, 0%; for the 750 mg/kg level—53%. 18%; for the 1,000 mg/level—79%, 57%, 57%; and for the 1,250 mg/kg level-33%, 20%, 73%. Ducklings with fz-induced congestive cardiomyopathy had decreased left ventricular free wall and ventricular septal thickness, increased left ventricular chamber diameter, increased left ventricular dilatation score, decreased absolute heart weight, and increased relative heart weight. Cardiac histopathologic changes were minimal; some ducklings had myocytolysis. Liver and lungs were congested. Furazolidone-induced cardiomyopathy in ducklings offers a model for studies of congestive cardiomyopathy in a species that is free from the hereditary cardiomyopathy (“round heart disease”) seen in turkeys.
Use of modified live feline panleukopenia virus vaccine to immunize dogs against canine parvovirus
Authors: Pollock Roy V. H. , Carmichael Leland E.
Published: February 2025

Modified live feline panleukopenia virus (fplv) vaccine protected dogs against canine parvovirus (cpv) infection. However, unlike the long-lived (≥ 20-month) immunity engendered by cpv infection, the response of dogs to living fplv was variable. Doses of fplv (snow leopard strain) in excess of 105.7 tcid50 were necessary for uniform immunization; smaller inocula resulted in decreased success rates.

The duration of immunity, as measured by the persistence of hemagglutination-inhibiting antibody, was related to the magnitude of the initial response to vaccination; dogs with vigorous initial responses resisted oronasal cpv challenge exposure 6 months after vaccination, and hemagglutination-inhibiting antibodies persisted in such dogs for > 1 year.

Limited replication of fplv in dogs was demonstrated, but unlike cpv, the feline virus did not spread to contact dogs or cats. Adverse reactions were not associated with living fplv vaccination, and fplv did not interfere with simultaneous response to attenuated canine distemper virus.
Pharmacokinetics of dexamethasone and its effect on adrenal gland function in the dog
Authors: Toutain Pierre L. , Alvinerie Michel , Ruckebusch Yves
Published: February 2025

The pharmacokinetics of dexamethasone (dxm) was studied in a group of 5 dogs given dxm alcohol or dxm 21-isonicotinate (as a solution) iv or im (1 mg/kg of body weight) and dxm 21-isonicotinate (as a suspension) im (0.1 or 1 mg/kg). Plasma concentrations were determined, using a high-performance liquid chromatography method. After iv administration, the half time of elimination was similar (120 to 140 minutes) for both formulations. In addition, all other pharmacokinetic parameters were not significantly different, indicating that dxm 21-isonicotinate renders dxm almost totally available. After im administration, absorption was rapid for both solutions with a peak plasma concentration at 30 to 40 minutes. Bioavailability was approximately 100% for dxm alcohol, but limited (40%) for dxm 21-isonicotinate. After im administration of dxm 21-isonicotinate (as a suspension) at 2 dosage rates (0.1 or 1 mg/kg), dxm was not detected in the plasma, suggesting a long phase of absorption. Plasma hydrocortisone (cortisol) values were similar after im and iv administrations of dxm alcohol and dxm 21-isonicotinate (as a solution); after a short increase lasting 15 minutes, plasma hydrocortisone values decreased and returned to base line after a delay of 24 to 48 hours. After im administration of dxm 21-isonicotinate as a suspension, plasma hydrocortisone values decreased for up to 10 days after the low dosage rate (0.1 mg/kg) and 1 month after the higher dosage rate (1 mg/kg).
Molecular epizootiologic studies of equine herpesvirus-1 infections by restriction endonuclease fingerprinting of viral DNA
Authors: Allen G. P. , Yeargan M. R. , Turtinen L. W. , Bryans J. T. , McCollum W. H.
Published: February 2025

The DNA from 297 field isolates of equine herpesvirus-1 (ehv-1) were analyzed by digestion with 5 restriction endonucleases (BamHI, EcoRI, BglII, SalI, and SstI). Two markedly different DNA cleavage patterns, designated subtypes 1 and 2 were found among the ehv-1 isolates. The majority of 25 respiratory tract isolates possessed subtype 2 DNA fingerprint patterns, and all but 1 of the 272 fetal isolates exhibited the subtype 1 fingerprint type. More subtle genomic heterogeneity could be demonstrated within each major subtype of ehv-1 on the basis of loss or gain of 1 or more cleavage sites for the 5 restriction endonucleases used. A minimum of 16 different DNA fingerprints occurred among subtype 1 isolates of ehv-1, while subtype 2 isolates could be further subdivided into 13 different cleavage patterns. Fetal isolates were encountered which possessed DNA fingerprints identical to those of 2 modified live-virus vaccine strains used for vaccination of the aborting mares. Two subtype 1 strains of ehv-1 (1P and 1B) accounted for 90% of the total number of nonvaccine abortion isolates examined. Using as a basis for comparison only those DNA differences resulting from a loss or gain of restriction enzyme cleavage sites, virus isolates recovered from the same epizootic of abortion or respiratory tract disease nearly always possessed identical DNA fingerprint patterns. Minor variations were observed in the electrophoretic mobility of certain fragments from epidemiologically related ehv-1 isolates, as well as from clonal isolates derived from plaque-purified virus stocks. In contrast to the genetic heterogeneity exhibited by subtype 2 isolates, the majority of epizootiologically unrelated subtype 1 isolates of ehv-1 could not be differentiated from one another on the basis of the DNA fingerprints generated by digestion with the 5 restriction endonucleases used. The data indicate the existence of little genetic heterogeneity among ehv-1 subtype 1 isolates and that this ehv-1 subtype may not exist as the large number of cocirculating, genetically distinct strains commonly found for other herpesviruses.
Sodium retention and cortisol (hydrocortisone) suppression caused by dexamethasone and triamcinolone in equids
Authors: Slone D. E. , Purohit R. C. , Ganjam V. K. , Lowe J. L.
Published: February 2025

Three ponies and 1 horse were bilaterally adrenalectomized (badx). The initial hypoadrenal episode after badx was reversed with 20 mg of dexamethasone (dxm) im (n = 2) or 20 mg of triamcinolone (tmc) im (n = 2). Nine hypoadrenal crises were reversed with 20 mg of dxm given im (n = 4) or 20 mg of tmc given im (n = 5). Sodium and chloride retention and potassium excretion were documented based on changes in serum electrolytes and urinary excretion.

Eight intact adult horses were randomly assigned to 2 groups to study the effects of a single im injection of dxm (0.044 mg/kg of body weight) or tmc (0.044 mg/kg). Cortisol (hydrocortisone) suppression was found to be maximal (nondetectable amounts of cortisol) by 12 hours in both groups. Cortisol was again detectable in the dxm group at 24 hours after injection and was at pretreatment values at 168 hours. Cortisol was not detectable in the tmc group for 192 hours and did not reach pretreatment values until 336 hours.

The duration of the gluconeogenic effect was compared with the duration of cortisol suppression exerted by dxm and tmc in these intact animals. Assuming that the decrease in plasma glucose coincides with the decrease in glucocorticoid activity of the respective steroid, a relative hypoadrenocortical state was found in the animals treated with dxm between the 2nd and 7th day after treatment, whereas this state occurred between the 6th and 14th day after treatment with tmc.
Serum proteins in healthy Basenjis and Basenjis with chronic diarrhea
Authors: Breitschwerdt Edward B. , Barta Ota , Waltman Celeste , Hubbert Nancy L. , Pourciau Susan S. , Liu Wendy
Published: February 2025

A serologic survey was conducted to characterize the electrophoretic patterns of serum proteins in healthy Basenji dogs (n = 137) and Basenjis with chronic diarrhea (n = 32). Serum protein electrophoresis values for Basenjis were similar to previously reported values from dogs of other breeds. Dogs with histologically confirmed lymphocytic-plasmacytic enteritis had a statistically significant (P < 0.05) decrease in total protein, albumin, and albumin/globulin ratio. α2-Globulin and γ-globulin values were significantly increased in old dogs (9 years of age or older) with lymphocytic-plasmacytic enteritis. Although not statistically significant, γ-globulin values were generally increased in Basenjis with lymphocytic-plasmacytic enteritis when compared with the values in age-matched clinically healthy Basenjis.
Cardiopulmonary effects of butorphanol tartrate in dogs
Authors: Trim Cynthia M.
Published: February 2025

The effects of butorphanol given (iv) at dose levels of 0.1 and 0.4 mg/kg were evaluated in conscious dogs, n = 5 for each dose. Mild sedation occurred, though it was greater in dogs given the larger dose. Two dogs in each group panted, but PaCO2 was not significantly changed. Small, but significant, decreases in arterial blood pressure, heart rate, and PaO2 occurred (P < 0.05). Base excess developed a negative trend. The pcv and total protein decreased slightly in dogs given the smaller dose, but were unchanged with the larger dose. Plasma glucose remained within acceptable limits.
Characterization of the hemolysin produced by Haemophilus pleuropneumoniae
Authors: Nakai Toyotsugu , Sawata Akira , Kume Katsumi
Published: February 2025

Production and characterization of Haemophilus pleuropneumoniae hemolysin were investigated by using 5 serotype 2 strains. The hemolysin was produced in chicken meat-infusion broth medium both in stationary and in shaking cultures. In stationary culture, hemolytic activity against horse rbc reached max-imum at postincubation day 5 (at the late stage of stationary phase), and the activity was maintained at the same level for 2 days thereafter. The hemolytic activity of shaking culture reached a maximum at postincubation hour 9 (at the early stage of logarithmic-growth phase), gradually decreased, and disappeared at postincubation day 2. The hemolysin was shown to be an extracellular product of the bacterial cells.

The rbc of horses, rabbits, and sheep were highly susceptible to the hemolysin, and those of pigs and guinea pigs were less susceptible, whereas rbc of 60-day-old chicks were not susceptible. The hemolysin was not inactivated by autoclaving at 121 C for 2 hours, and by treatments with formalin, trypsin, or pronase. The presence of calcium or magnesium ions did not change the activity, whereas iodoacetic acid significantly reduced the activity.
Cardiovascular effects of submaximal aerobic training on a treadmill in Standardbred horses, using a standardized exercise test
Authors: Bayly W. M. , Gabel A. A. , Barr S. A.
Published: February 2025

Seven healthy, nonexercised, previously trained, adult Standardbred horses were allotted to 2 groups and trained 78 days on a treadmill set at a 7° 30' angle. The groups were trained on different schedules, and the effects of training on heart rate, cardiac output, stroke volume, arteriovenous oxygen difference, systemic blood pressure, and venous lactic acid were determined.

Measurements were made at rest, during exercise on the treadmill at rates of 55 m/min, 75 m/min, 100 m/min, and 154 m/min, and at 5 minutes after exercise (standardized exercise test).

Heart rate and cardiac output decreased during the training period. Significantly slower heart rates were observed at 55 m/min by day 8, at 100 m/min and 154 m/min by day 36, at 1 minute after exercise by day 57, and at 5 minutes after exercise by day 78 (P < 0.05). Stroke volume increased with exercise, but not significantly.

The arteriovenous oxygen difference increased significantly (P < 0.05) with each increase in work load. There was no significant increase with training, although an upward trend was recorded.

Mean systemic blood pressure did not differ from resting with treadmill rates of 55 m/min, 75 m/min, or 100 m/min. It was greater at 154 m/min, although this was not significant. During exercise, the total peripheral resistance decreased to as little as 30% of its resting value. After exercise, diastolic and mean arterial blood pressures and peripheral resistance increased. Marked increases in blood volume and blood viscosity during exercise were closely related to the decrease in peripheral resistance. There was no significant effect of training on blood pressure.

Venous lactic acid concentrations at rest were greater than those of the horses on the treadmill at rates of 55 m/min, 75 m/min, and 100 m/min and at 5 minutes after exercise on days 1, 8, and 15. Subsequently, they were not different from resting values.

Differences in the effects of the different training programs could not be detected.
Mechanical responses to peroneal nerve stimulation in halothane-anesthetized horses in the absence of neuromuscular blockade and during partial nondepolarizing blockade
Authors: Klein Lin , Hopkins Judy , Beck Ernest , Burton Bridget
Published: February 2025

Neuromuscular function in anesthetized horses was monitored by stimulating the peroneal nerve and recording the mechanical responses. Responses to stimulation at various frequencies during halothane anesthesia in the absence of neuromuscular blockade, during partied nondepolarizing blockade, and after pharmacologic antagonism of the blockade are reported.
Chromosome identification of the rusty-spotted cat (Felis rubiginosa): One more down and four to go
Authors: Centerwall Willard R. , Wurster-Hill Doris H. , Maruska Edward J. , Kramer Lynn W.
Published: February 2025

The chromosomes of the rusty-spotted cat, Felis rubiginosa, of Sri Lanka (Ceylon) were analyzed. Although the 38-chromosome complement of F rubiginosa closely resembles that of several other species, it seems to be unique with only minor variations in the D and F chromosomes. This reduces, from 5 to 4, the number of the 37 recognized world feline species not yet cytogenetically studied.

Despite great differences in size and distribution, the feline species of the world are one of the most homogenous families of mammals, with only subtle chromosomal differences separating most species. By comparative cytogenetic analyses, it is becoming possible to map the probable evolutionary pathway of the world’s cats.
Immunochemical studies to purify rabbit and chicken immunoglobulin G antibody by protein A-Sepharose chromatography
Authors: Ansari A. A. , Chang T. S.
Published: February 2025

The immunoglobulin (Ig) G binding properties of protein A made affinity chromatography with protein A an acceptable method for isolation of IgG in mammals. Rabbit IgG was isolated by fractionation of serum on a column containing protein A coupled to Sepharose. The IgG molecules of subclasses 1, 2, and 4 and their fragments containing the Fc region had this affinity, but not IgG-3. The second peak, after washing with 1M acetic acid eluate (pH 7.0) as shown in the Ouchterlony agar immunodiffusion test, was the IgG fraction. Similar studies on normal and hyperimmune chicken sera indicated that chicken IgG does not bind to protein A molecules. Further studies indicated that chicken plasminogen did not bind covalently to protein A molecules and subsequently did not interfere in the affinity of protein A to bind to IgG molecules. The inhibition of binding of chicken IgG to protein A molecule is still unknown.
Comparison of two oxytetracycline formulations in the treatment of laboratory-induced pasteurellosis of pigs
Authors: George Lisle W. , Magonigle Robert , Weiss Raul
Published: February 2025

Two experiments were performed. In the first, pigs were given an intratracheal inoculation of Pasteurella multocida and then were either left untreated (group T1; n = 10) or 4 hours later, were given a commercially available oxytetracycline formulation. Pigs (group T2; n = 10), one of the antibiotic treatment groups, were given an im administration (11 mg of antibiotic/kg of body weight) of a formulation containing oxytetracycline (50 mg/ml). The dose was repeated 12 hours later. The pigs in the other treated group (group T3; n = 10) were given a single im administration (20 mg of antibiotic/kg of body weight) of a long-lasting formulation containing oxytetracycline (200 mg/ml). On the 7th post inoculation day, all of the pigs that survived were euthanatized. Necropsies were performed on all pigs immediately after death. By the 7th day after the pigs were inoculated, 7 of the controls and 1 of the 1-time treated pigs (200 mg/ml formulation) had died. Clinical signs and pathologic changes in the lungs of the pigs given the 200 mg/ml formulation were similar to those in the pigs given the 2 doses of the 50 mg/ml formulation. In general, both groups of treated pigs gained more weight, were less depressed (cns), had lower total wbc counts, and had less severe lung lesions than did the controls.

In the 2nd experiment, serum antibiotic concentrations produced by each formulation were measured in pigs. Four pigs were given either 1 im dose, or 2 equivalent doses (11 mg/ kg of body weight) spaced 12 hours apart of the 50 mg/ml formulation. Ten days later, 4 of the pigs were given a single im dose (20 mg of oxytetracycline/kg of body weight) of the 200 mg/ml formulation. In all pigs, the average peak serum antibiotic concentrations were similar in magnitude and occurred 2 hours after the drugs were administered. The pigs given the 50 mg/ml formulation twice and the 200 mg/ml formulation once had serum oxytetracycline concentrations exceeding 1 μg/ml for 48 hours. The average serum oxytetracycline concentration of pigs given a single dose of the 50 mg/ml formulation was < 0.5 μg/ml by 16 hours.
Relation of lipid content and exotoxin production to virulence of Corynebacterium pseudotuberculosis in mice
Authors: Muckle C. A. , Gyles C. L.
Published: February 2025

Twenty-five isolates of Corynebacterium pseudotuberculosis from lesions of caseous lymphadenitis in goats were examined for cell wall lipid content, exotoxin production, and virulence in mice. The mean percentage of lipid content was 6.52% and significant (P < 0.005) differences were demonstrated between some isolates. Exotoxin in broth culture filtrates of the 25 isolates was measured by the staphylococcal β-hemolysin inhibition (bhi) test and a radioassay for phospholipase D. All isolates were positive for exotoxin in both tests and 1 isolate had higher activity than the others. Because the correlation between the bhi test and radioassay was poor, it may be that the radioassay detects only enzymatically active exotoxin, whereas the bhi test detects active and inactive exotoxin. All isolates were virulent in mice at 2 dosage levels used to produce subacute-chronic and acute disease. Differences in virulence among isolates were detected only at the lower dosage level. There was a direct relationship between percentage of lipid and induction of chronic abscessation in mice, but not between lipid content and mortality. Although exotoxin production in vitro could not be related quantitatively to virulence, the results of inoculating mice with bacterial cells and broth culture supernatant were consistent with a role for exotoxin in disease.
Distribution of abscesses and shedder state in swine inoculated with group E streptococci via routes other than oral
Authors: Miller R. B. , Olson L. D.
Published: February 2025

The pathogenesis of group E streptococcal abscesses of swine which occur at sites other than the head and neck (atypical sites) was studied after groups of swine were each inoculated by 1 of 4 routes (intragastric, intraenteric, footpad, or intratracheal). Abscesses were observed in the head and neck of all swine and at atypical sites in 3 of the 5 swine inoculated by the intragastric route. In 20 swine inoculated by the intraenteric route, head and neck abscesses were recognized in 7 and abscesses at atypical sites occurred in 11. Inoculation by footpad scarification induced head and neck abscesses in 1 of 5 swine and atypical sites abscesses in 2 of 5 swine. Intratracheal inoculation produced head and neck abscesses in 3 of 5 swine and an abscess at an atypical site (lung parenchyma) in 1 of the 3 with head and neck abscesses. Four of 5 noninoculated swine had abscesses in the mandibular lymph nodes 55 days after they had access to a manure pit used also by swine inoculated by footpad scarification. Abscesses in atypical sites were not recognized in 29 sentinel swine with abscesses exposed by nose and/or oral contact.

In transmission studies, all principal swine were inoculated with group E streptococcus by the intraenteric route. A group of 5 principals transmitted the organism to 1 of 2 susceptible penmates. Each of another 5 principals transmitted group E streptococcus to 4 of 5, 4 of 4, 3 of 4, 3 of 4, and 2 of 4 of their respective contact sentinels. In the last experiment, when 5 swine were inoculated and penned separately, 2 of 2 transmitted group E streptococcus by drinking water, 2 of 3 transmitted group E streptococcus by drinking water and/or nose contact, and 2 of 5 transmitted group E streptococcus by their feces. Transmission was determined by isolation of group E streptococcus from sentinel abscess exudate. In the last experiment, transmission also was determined by a microtitration agglutination test.
Contagious equine metritis: Distribution of organisms in experimental infection of mares
Authors: Acland H. M. , Allen P. Z. , Kenney R. M.
Published: February 2025

After contagious equine metritis bacteria were inoculated into the uterus of mares, genital tract tissues were examined for presence of the organism by bacteriologic cultural technique and an indirect immunofluorescent staining technique. Up to 14 days after mares were inoculated, the organism was frequently in the lumen of the uterus and in the cervix and, less frequently, in the vagina, vestibule, clitoral fossa, clitoral sinus, and uterine tubes. After 21 to 116 days, the organism was occasionally found on the ovarian surface, in the uterine tubes, uterus, cervix, and vagina and more frequently in the clitoral sinus and clitoral fossa. The distribution of organisms in the remainder of the genital tract was not different in mares that had been clitorectomized.
Depression of polymorphonuclear leukocyte function associated with experimentally induced Escherichia coli mastitis in sows
Authors: Löfstedt J. , Roth J. A. , Ross R. F. , Wagner W. C.
Published: February 2025

In a study of susceptibilities of sows from 2 herds to experimentally induced Escherichia coli mastitis, a marked difference was seen. The “susceptible” sows were from a conventional herd and “resistant” sows were from a specific-pathogen-free herd. The purpose of the study was to determine whether deficient neutrophil function was associated with increased susceptibility to E coli-induced mastitis. Four in vitro procedures were used to evaluate polymorphonuclear leukocyte (pmn) function: (i) random migration under agarose, (ii) ingestion of 125I-iododeox-yuridine-labeled Staphylococcus aureus, (iii) quantitative nitroblue tetrazolium reduction, and (iv) iodination.

After parturition and intramammary inoculation with E coli, sows from the susceptible herd were neutropenic and the neutrophils which were present in the peripheral blood had reduced function. Specifically, there were depressed random migration under agarose, S aureus ingestion, and iodination when compared with pmn function in resistant sows. These data indicate that susceptibility to E coli mastitis was associated with deficiencies in pmn numbers and function. Potential causes of the neutrophil dysfunction are discussed and include possible systemic hormonal aberrations or the presence of an inapparent viral or bacterial infection.
Analysis of serum and lymphocyte surface IgM of healthy and immunodeficient horses with monoclonal antibodies
Authors: McGuire Travis C. , Perryman Lance E. , Davis William C.
Published: February 2025

Nine monoclonal antibodies which reacted with equine immunoglobulin (Ig)M and not other equine Ig and serum proteins were prepared. Cells producing antibodies (C 1.9) which precipitated with IgM and bound to staphylococcal protein A were triple-cloned (C 1.9/3.2) and the antibodies further characterized. Monoclonal antibody C 1.9/3.2 reacted with an IgM determinant present on serum IgM from horses of several breeds. Studies with 125I-labeled IgM revealed the presence of this determinant on all IgM molecules. The monoclonal antibody enabled quantitation of IgM in presuckling foal and adult horse sera, using rocket electrophoresis. This procedure was used because presumably it gives a positive precipitation reaction over a wide range of antigen-antibody ratios. The C 1.9/3.2 monoclonal antibody recognized an exposed μ-chain determinant on live B lymphocytes, as determined by immunofluorescence, Also, IgM-containing cells could be identified in acetone-fixed frozen sections of lymphoid tissue. Sera from several other species carry the determinant identified by C 1.9/3.2, suggesting that the reagent may be useful for IgM studies in other species.
In vivo harboring of equine herpesvirus-1 in leukocyte populations and subpopulations and their quantitation from experimentally infected ponies
Authors: Scott J. C. , Dutta S. K. , Myrup A. C.
Published: February 2025

Pony foals were experimentally inoculated with equine herpesvirus-1 (ehv-1) to detect and quantitate the in vivo presence of the virus in peripheral blood leukocyte populations and subpopulations, plasma, and nasal secretions. Pony foals had typical clinical signs of respiratory tract disease and developed a transient lymphopenia that peaked on postinoculation day (pid) 4 involving T and B lymphocytes. However, the relative proportions of the lymphocytes subpopulations remained constant during the course of the lymphopenia.

Equine herpesvirus-1 was not detected by plaque assay from the disrupted leukocytes. It was detected 4 from the mononuclear cells and sub-populations (T cells, B cells, and monocytes) by infective center (ic) assay by cocultivation of intact cells onto permissive equine monolayer cell cultures.

After mitogen stimulation in culture, virus was detected in a higher number of these cells by ic assay, and a large concentration of virus was also detected by plaque assay. The highest number of mononuclear cells harboring virus was on pid 4 with a value of 43 ic/2 × 106 and 514 ic/2 × 106 cells and 0 plaque-forming unit (pfu)/ml and 6,803 pfu/ml for noncultured and cultured cells, respectively. Of the mononuclear cells, the predominant cells harboring virus were the T lymphocytes with peak values on pid 4 of 76 ic/2 × 106 and 851 ic/2 × 106 cells for noncultured and cultured cells, respectively. The corresponding plaque-assay titers were 0 and 10,464 pfu/ml, respectively. A lower number of B lymphocytes and monocytes contained virus on pid 4. Virus was detected in the mononuclear cells up to pid 14. The virus was not detected in neutrophils, before and after culture, by ic assay or plaque assay.

A low and variable concentration of ehv-1 was detected from the plasma samples up to pid 7, and on subsequent days, it was not detected. The virus was recovered from nasal swab samples up to pid 14 to 20. Seemingly, ehv-1 is a T-lympho-tropic herpesvirus.