bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosis of persistent aphthovirus infection and its differentiation from vaccination response in cattle by use of enzyme-linked immunoelectrotransfer blot analysis with bioengineered nonstructural viral antigens
Authors: Bergmann Ingrid E. , de Mello Paulo Augé , Neitzert E. , Beck E. , Gomes I.
Published: January 2024

A highly sensitive enzyme-linked immunoelectrotransfer blot (eitb) assay, capable of detecting aphthovirus-specific antibodies to replicating virus in sera from cattle with persistent infection, was developed. The assay uses a set of purified recombinant dna-derived nonstructural viral antigens as serologic probes in lieu of the traditionally used virus infection-associated antigen(s) partially purified from baby hamster kidney-infected cells.

Sera from cattle with experimentally induced aphthovirus infection were analyzed sequentially by eitb at various postinoculation days, and the results were compared with those obtained by currently used techniques. It was established that, in all cases, eitb results remained positive at late stages of infection. At these times, results of virus infection-associated antigen-antibody determinations were negative by use of the conventional immunodiffusion in agarose gel test, and virus was recovered only occasionally from esophageal-pharyngeal fluid.

Specificity of the eitb test was indicated by negative results for sera from cattle in aphthovirus-free areas, including samples from cattle infected with a variety of bovine viruses. Moreover, the test eliminated a substantial number of false-positive results (on the basis of the immunodiffusion in agarose gel assay) caused by reactivity of sera from vaccinated cattle. Use of additional nonstructural viral antigens, other than rna polymerase, is proposed to differentiate between seropositivity resulting from vaccination or infection. This procedure may be considered to have potential applications as a sensitive, safe, rapid, and economic field test for specific diagnosis of persistent aphthovirus infection in affected animals.
Evaluation of intraocular penetration of topically administered tissue plasminogen activator in dogs
Authors: Gerding Paul A. , Eurell Thomas E.
Published: January 2024

Topically administered tissue plasminogen activator (tPA) was evaluated for its penetration into aqueous humor of clinically normal dogs. Two concentrations of tPA (5 mg/ml and 10 mg/ml) were evaluated in a single-dose study, and a concentration of 5 mg of tPA/ml was used for a multiple-dose study. The contralateral eye served as a nontreated control. Enzyme substrate analysis of aqueous humor was used to determine tPA activity. The activity of tPA in aqueous humor was significantly (P ≤ 0.05) greater in treated eyes of all dogs, compared with that in control eyes. Significant differences in activity of tPA were not detected at different doses in treated eyes.
Cytokeratins as markers of initial stages of squamous metaplasia in feline mammary carcinomas
Authors: Ivanyi D. , Minke J. M. H. M. , Hageman Ph. C. , Groeneveld E. , van Doornewaard G. , Misdorp W.
Published: January 2024

Expression of keratins (cytokeratins, ck) known to be suitable markers for different types of epithelial differentiation was analyzed in specimens of feline mammary tissue. A panel of specific anti-ck monoclonal antibodies (MAb) was used to determine ck distribution pattern in normal feline tissues (n = 3), and in benign (n = 18) and malignant (n = 20) feline mammary tumors. In selected tumors, the ck distribution pattern was also determined by biochemical methods. A MAb specific for α-smooth muscle actin was used to discriminate between myoepithelial cells and luminal epithelial cells.

In normal mammary gland tissues, 6 MAb reacted exclusively, either with myoepithelial cells or with luminal epithelial cells. Luminal epithelial cells reacted with MAb specific for ck typical of simple epithelia, whereas myoepithelial cells reacted with MAb specific for ck in basal cells of stratified epithelia. A similar distribution of ck was detected in specimens from benign tumors, except that ck4 was not detected in normal mammary gland tissues and was detected in some ducts in specimens with adenosis. Almost all tumor cells in specimens from malignant tumors reacted with MAb specific for ck typical of simple epithelia. Concomitant expression of ck typical of stratified epithelia was detected in small or large subpopulations of tumor cells in 70% of carcinomas. Cytokeratins typical of basal cell layers and typical for suprabasal layers of inner stratified epithelia were detected. Cytokeratins typical of stratified epithelia were always found in areas of squamous metaplasia, but also were found in adenocarcinomal cells surrounding these areas. We postulate that these adenocarcinoma cells represent transitional cells where the initial stages of squamous metaplasia have taken place, but squamous metaplasia is not yet detectable by light microscopy.
Isolation and characterization of porcine milk lactoferrin
Authors: Chu Redman M. , Wang Shih-Rong , Weng Chung-Nan , Pursel Vernon G.
Published: January 2024

We purified porcine whey lactoferrin by affinity chromatography on a heparin-Sepharose column, followed by high-performance liquid chromatography. Molecular mass of purified lactoferrin (plf) is 78,000 daltons. The iron-binding activity of plf had a uv/visible-light absorption spectrum indistinguishable from that of human and bovine lactoferrins (absorbance ratio [465 nm/280 nm] approx 0.046). The growth ratio of WIL-2 cells in plf-supplemented medium is 70% of that in serum-containing medium. The aforementioned characteristics are similar to those of human and bovine lactoferrins. Immunoblot analysis, using polyclonal antibody raised in rabbits against porcine whey lactoferrin, revealed high specificity for plf, and low cross-reactivity with commercial human and bovine lactoferrins.
Histomorphometric analysis of the omasum of sheep during development
Authors: Franco A. , Robina A. , Regodón S. , Vivo J. M. , Masot A. J. , Redondo E.
Published: January 2024

Histomorphometric and scanning electron microscopic analyses were performed on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histologic differentiation of the omasum took place at 33 days of fetal life, with the appearance of first-order laminae. Second-, third-, and fourth-order laminae appeared at 39, 50, and 59 days, respectively. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life, decreasing quantitatively until birth, before subsequently stabilizing in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Growth curves and formulas were constructed for each tissue layer. Initial tests involved multiplicative (y = axb), exponential (y = EXP [a + bx]), linear (y = a + bx), and polynomial models (y = a + bx + cx2 + dx3).
Variation of abscess formation in cattle after vaccination with a modified-live Pasteurella haemolytica vaccine
Authors: Littledike Ernest Travis
Published: January 2024

During the spring of the first year of a vaccine study, 57 of 238 calves (24%), in which modified-live Pasteurella haemolytica vaccine (mlv) was injected twice, developed 1 or more abscesses. Abscesses were not observed after multiple visual examinations of 437 calves given killed P haemolytica bacterin or placebo injections of similar adjuvants used in the vaccine and bacterin. Calves that developed abscesses after the second injection of mlv weighed significantly (P < 0.05) less (on the basis of body weight adjusted for weaning weight) at the second injection than did those that did not develop abscesses. Compared with calves given mlv that did not develop observable abscesses, calves developing abscesses after the second injection of mlv weighed 11.0 and 14.2 kg less, respectively, at 56 days and 112 days after injection, and they had 11.0 kg less gain at 56 days after injection. Abscess prevalence tended to be highest on certain days or at certain locations used for cattle processing, and the prevalence of abscesses increased in cattle processed later on a given day. Abscesses were not observed in 2 other groups of similarly treated calves vaccinated in the autumn or in the subsequent spring.
Evaluation of limb symmetry indices, using ground reaction forces in healthy dogs
Authors: Budsberg Steven C. , Jevens Dermot J. , Brown John , Foutz Tim L. , DeCamp Charles E. , Reece Lynn
Published: January 2024

Limb symmetry was evaluated by measuring ground reaction forces in 2 groups of normal-gaited dogs at a trot. Data were collected from 2 groups of 21 dogs trotted at dog/handler velocities of 1.25 to 1.55 m/s and 1.85 to 2.05 m/s, respectively. Of these dogs, 9 participated in both groups to allow comparison of data at both velocities. Additionally, 16 of the dogs in group 1 were measured in 2 directions of movement to determine whether directional dependence was present. Collected data were then applied to 3 described symmetry indices.

Each index was easy to calculate, but all had limitations. A major limitation was variation in magnitude of ground reaction forces measured between the different axes and the effect of this variation on precision of the derived indices. Vertical ground forces provided the most consistent symmetry indices, in part because of their large magnitude. The indices indicated that no dog had perfect right-to-left symmetry during a trotting gait. Statistical differences were not found in any of the measurements of directional dependence. Likewise, comparing symmetry data in dogs trotted at both velocities indicated no significant differences in any axis.

However, further analysis of the data revealed the actual amount that a variance attributable to right-left limb variation was negligible. Most of the variance was attributable to trial variation. Thus, the aforementioned indices, which use nonconsecutive footfall methods to evaluate limb symmetry, actually measure principally trial variation and not limb-to-limb variation.
Evaluation of the indirect fluorescent antibody test for diagnosis of Babesia gibsoni infections in dogs
Authors: Yamane I. , Thomford J. W. , Gardner I. A. , Dubey J. P. , Levy M. , Conrad P. A.
Published: January 2024

We determined the extent of the serologic cross-reactivity in the indirect fluorescent antibody (ifa) test for Babesia gibsoni, and the optimal cut-off titer for seropositivity in the test. The lowest titer to B gibsoni detected in a dog with naturally acquired clinical babesiosis was 1,280, and 7 of 12 dogs had titer between 10,240 and 20,480. Two experimentally infected normosplenic dogs developed high titer (40,960 to 81,920) to B gibsoni, and the same sera reacted in ifa tests for B canis (titer ≤ 640), Toxoplasma gondii (titer ≤ 2,560), and Neospora caninum (titer ≤ 10,240). Dogs that were experimentally infected with B canis and T gondii had titer ≤ 160 to B gibsoni. Dogs that were experimentally infected with N caninum had titer (80 to 10,240) to N caninum, but failed to have serologic reactivity to B gibsoni. Serologic titer of healthy dogs from Australia, a country where B gibsoni is not known to exist, was ≤ 160 to B gibsoni. On the basis of these findings, a cut-off titer of 320 was considered to be appropriate for serodiagnosis of B gibsoni in dogs with clinical signs of babesiosis. A more conservative titer of 1,280 was established as the cut-off titer for seroepidemiologic studies based on relative costs and benefits of false-positive results and failure to isolate B gibsoni parasites after splenectomy and immunosuppression from a clinically normal dog with B gibsoni titer of 640. Results of the study indicate the importance of establishing optimal cut-off titer for the B gibsoni ifa test that takes into consideration the purpose of the test, seroreactivity to antigenically related parasites, and factors that contribute to interlaboratory test variation.
Use of a DNA probe to detect the intracellular organism of proliferative enteritis in swine feces
Authors: Jones Gary F. , Ward Gilbert E. , Gebhart Connie J. , Murtaugh Michael P. , Collins James E.
Published: January 2024

A method of extracting bacterial dna from swine feces was developed and used in a molecular assay for the presence of ileal symbiont (is) intracellularis, formerly known as the Campylobacter-like organism associated with swine with proliferative enteritis. Hybridization with a digoxigenin-labeled, is intracellularis-specific probe detected the presence of is intracellularis at a concentration of 107 organisms/g of feces. This method was sufficient to detect is intracellularis in the feces of swine with experimentally induced and naturally acquired infection. Results of the hybridization were in agreement with those from histologic postmortem examination.
Efficacy of Pasteurella haemolytica subunit antigens in a goat model of pasteurellosis
Authors: Purdy Charles W. , Straus David C. , Struck Douglas , Foster Gene S.
Published: January 2024

The effectiveness of Pasteurella haemolytica biovar A, serovar 1 (Ph1) subunit vaccines was tested in goats, using challenge exposure by transthoracic injection. Twenty-two weanling male Spanish goats were randomly allotted to 4 groups. Six goats were given 2 transthoracic injections into the lung 18 days apart with live Ph1 impregnated in agar beads (positive controls). Six goats were not given injections (negative controls). Five goats were given 2 transthoracic injections into the lung 18 days apart with 4.6 mg of cytotoxin in agar beads. The remaining 5 goats were given 2 im injections, 18 days apart, into the thigh with 4.6 mg of cytotoxin emulsified in incomplete Freunds’ adjuvant. Twenty-four days after the second injection, all goats were challenge-exposed to live Ph1 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Serum neutralizing anticytotoxin titer was measured throughout the experiment. Mean volume of consolidated lung tissue was 0.38 cm3 for the positive control group, 32 cm3 for the negative control group; 19 cm3 for the cytotoxin-lung group; and 88 cm3 for the cytotoxin-adjuvant-im group. Only the positive control group was protected from Ph1 challenge exposure. The Ph1 cytotoxin subunit vaccine alone appeared to be ineffective, and the anticytotoxin titer was not correlated with protection.

In a separate trial, 32 weanling male Spanish goats were randomly allotted to 5 groups. Each was given 2 transthoracic injections into the lung 22 days apart. Six goats were given Ph1 cytotoxin impregnated into agar beads; 6 were given Ph1 lipopolysaccharide impregnated in agar beads; 6 were given Ph1 capsule impregnated in agar beads. Six goats were given agar beads only (negative controls), and 6 were given live Ph1 impregnated into agar beads (positive controls). Twenty days after the second injection, all goats were challenge-exposed to live Ph1 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied. Mean volume of consolidated lung tissue was 0.14 cm3 for the positive control group, 7.59 cm3 for the negative control group, 11.21 cm3 for the cytotoxin group, 10.19 cm3 for the lipopolysaccharide group, and 1.6 cm3 for the capsule group. Again, only injection of live Ph1 (positive controls) induced solid protection; however, the capsule subunit vaccine induced partial protection against challenge exposure in this trial. Lipopolysaccharide and cytotoxin subunit vaccines were ineffective in protecting goats against challenge exposure with live Ph1.
Delayed seroconversion following naturally acquired caprine arthritis-encephalitis virus infection in goats
Authors: Rimstad E. , East N. E. , Torten M. , Higgins J. , DeRock E. , Pedersen N. C.
Published: January 2024

One hundred eight milking goats from a dairy that had been using a modified caprine arthritis-encephalitis virus (caev) eradication program were tested for caev antibodies by serologic methods and for proviral caev dna by use of polymerase chain reaction (pcr) technology. All goats were free of clinical symptoms of caev infection. Twenty-seven of the 108 goats were considered seropositive, on the basis of elisa results. Proviral caev dna was detected, using pcr techniques, in mononuclear leukocytes in blood samples obtained from 25 of the these 27 seropositive goats. Twenty of the 81 seronegative goats also had positive pcr test results. Ten of these goats seroconverted by 8 months later, and virus was readily isolated from mononuclear leukocytes in venous blood samples after the goats had seroconverted. Virus was also isolated from mononuclear leukocytes in blood samples collected from 4 of 11 goats that were seronegative, but had positive pcr test results. These results indicated that seroconversion can be delayed for many months following natural infection with caev. Delayed seroconversion appears to be a feature of caev infection, which may have direct implications for caev eradication programs and epidemiologic studies that rely on serologic methods to detect infected goats.
Cytologic responses of Staphylococcus aureus-infected mammary glands of heifers to interferon gamma and interleukin-2 treatment
Authors: Quiroga German H. , Sordillo Lorraine M. , Adkinson R. Wayne , Nickerson Stephen C.
Published: January 2024

Cytologic and bacteriologic responses, and changes in cytokine activity were evaluated in secretions of Staphylococcus aureus-infected mammary glands after treatment of heifers with recombinant bovine interferon gamma (rbIFNγ) or interleukin 2 (rbIL-2). Two groups of 4 heifers each, experimentally infected with 107 colony-forming units (cfu) of S aureus, were injected in 2 quarters via the teat canal, with 105 U of rbIFNγ (trial 1) or 7.5 × 105 U of rbIL-2 (trial 2) 2 weeks after experimentally induced infection; control quarters received phosphate-buffered saline solution. Mammary secretion samples were taken on days 0, 1, 2, 3, 4, 7, and 14 after cytokine infusion. Secretions were diluted 1:10 and used to perform somatic cell counts (scc), differential cell counts, and cfu enumerations, and to determine the number of leukocytes expressing major histocompatibility complex class-II (mhc II) antigens. In addition, mammary secretion samples taken on days 0, 1, and 2 were processed to obtain skimmed milk for evaluation of rbIFNγ- and rbIL-2-like activities. Treatment with rbIFNγ did not influence scc, or differential or bacteria counts, or the number of leukocytes expressing mhc II antigens. However, rbIL-2 stimulated leukocytosis, which may have reduced bacteria counts early in the trial; treatment with this cytokine also increased the neutrophil, macrophage, lymphocyte, and eosinophil counts in secretions. Similarly, numbers of mhc II-positive leukocytes were greater in rbIL-2-treated quarters vs controls. Compared with day 0, IFNγ-like activity was increased on only day 1 in both trials. Interleukin-2-like activity was not influenced in the rbIFNγ trial, but was increased on days 1 and 2 in the rbIL-2 trials. Results indicated that neither cytokine may have had a major influence on the course of established S aureus infections. However, the increased scc in rbIL-2-treated quarters may have accounted for the reduction in cfu throughout the trial after treatment with this cytokine. Greatest cytokine-like activity was observed on day 1; however, the consequences of cytokine activity, such as the sustained eosinophilia after rbIL-2 treatment, were detected over the 14-day trial period, indicating possible prolonged action.
Effects of ephedrine on cardiovascular function and oxygen delivery in isoflurane-anesthetized dogs
Authors: Wagner Ann E. , Dunlop Colin I. , Chapman Phillip L.
Published: January 2024

The hemodynamic effects of 2 dosages of ephedrine were studied in 6 dogs anesthetized with isoflurane only (end-tidal concentration equivalent to 1.5 times minimum alveolar concentration). Following instrumentation, baseline (time 0) measurements included heart rate (hr), respiratory rate, mean arterial blood pressure (map), cardiac output, and blood gas tensions. Cardiac index (ci), stroke volume (sv), systemic vascular resistance (svr), arterial oxygen content (Cao2), and oxygen delivery and consumption (Do2 and Vo2, respectively) were calculated. Three dogs were given ephedrine iv at a dosage of 0.1 mg/kg of body weight, and 3 dogs were given ephedrine iv at a dosage of 0.25 mg/kg. Measurements were recorded at 5, 10, 15, 30, and 60 minutes. Each dog then received the alternate dosage of ephedrine, and measurements were again recorded at the same intervals. Effects of ephedrine varied with dosage. Neither dosage was associated with significant changes in pH, Pao2, Paco2, Vo2, or respiratory rate. Ephedrine at a dosage of 0.1 mg/kg caused transient significant increases in map, ci, sv, Cao2, and Do2, significant decreases in hr and svr, and a late, slight decrease in Cao2. Ephedrine at a dosage of 0.25 mg/kg caused a greater and more prolonged increase in map, as well as increases in ci, sv, and svr, and a decrease in hr. The higher dosage of ephedrine also caused a pronounced increase in hemoglobin concentration and CaO2, resulting in a 20 to 35% increase in Do2 throughout the 60-minute experiment.
Lymphocyte proliferative responses in neonatal pigs with high or low plasma cortisol concentration after stress induced by restraint
Authors: Brown-Borg H. M. , Klemcke H. G. , Blecha F.
Published: January 2024

High plasma cortisol concentration is associated with perception of stress and reduced immune function in pigs. Neonatal pigs (12, 19, or 26 days old) were tested to determine maximal cortisol response to a mild restraint stressor. Pigs were fitted with indwelling jugular cannulas 4 days prior to restraint. One day before restraint, 10 ml of blood was removed for lymphocyte isolation and subsequent in vitro lymphocyte proliferation and interleukin 2 (il-2) assays. On the day of restraint, blood samples were drawn 10 minutes before and 3, 10, and 20 minutes after holding each pig in a supine position for 1 minute. Plasma cortisol concentration was determined by use of radioimmunoassay. Pigs with maximal cortisol response greater than the mean value for that age group were classified in the high-responder (hires) group. Conversely, those with values lower than the mean maximal response were assigned to the low-responder (lores) group. The HIRES pigs had larger relative adrenal gland weights and higher baseline and maximal cortisol responses, compared with lores pigs (P = 0.0170, P = 0.0002, P = 0.0001, respectively). Mitogen-induced lymphocyte proliferative responses (to phytohemagglutinin, concanavalin A, and pokeweed mitogen) were 60% lower (P = 0.0037, P = 0.0432, P = 0.0103, respectively) in hires vs lores pigs. In vitro il-2 production did not differ between hires and lores pigs. Lymphocyte proliferation induced by the B-cell mitogen, pokeweed mitogen, decreased 56% with age (P = 0.0151). Production of il-2 was numerically decreased (P = 0.06) by 50% in 26-day-old pigs, compared with earlier ages. These results indicate that neonatal pigs with low cortisol response to stress may have an advantage, from an immunologic standpoint, over pigs prone to stress.
Pharmacokinetics of L-thyroxine after its oral administration in dogs
Authors: Nachreiner R. F. , Refsal K. R. , Ravis W. R. , Hauptman J. , Rosser E. J. , Pedersoli W. M.
Published: January 2024

Twelve mature (5 sexually intact males, 4 castrated males, and 3 females) mixed-breed dogs were surgically thyroidectomized and used in a Latin-square design pharmacokinetic study of orally administered l-thyroxine. The dogs were treated with 44, 22, and 11 μg of l-thyroxine/kg as a single morning dose or in divided doses, morning and evening. Serum concentration of thyroxine (T4) was evaluated to determine a number of pharmacokinetic variables for comparison. Mean steady-state concentrations (Css) were determined from the area under the curve. Variables were analyzed for comparisons between dosages by use of anova.

Concentration at steady state was highest for dogs of the 44-μg/kg of body weight once-daily group and was lowest for dogs of the group given 11 μg/kg in 2 daily doses. Single daily administration resulted in higher Css, except at the 22-μg/kg/d dosage. Clearance was faster for the 22- and 44-μg/kg/d dosages than for the 11-μg/kg/d dosage. The half-life (t1/2) and mean residence time (mrt) also were shorter for the 44-μg/kg/d dosage, possibly indicating more rapid elimination of the drug at higher doses and dose-dependent kinetics. Perhaps, as the dogs’ metabolism increased with higher iodothyronine concentrations, hormone degradation was accelerated. Interval (divided vs single dose) caused some expected changes: maximal concentration was higher and minimal concentration was lower when single administration was used. These undulations resulted in iodothyronine concentrations above the physiologic range for a number of hours, whereas concentration closer to physiologic ranges was achieved by use of divided doses. Delayed absorption (lag time) was seen in 37 of the 72 data sets, but was generally short, about 0.25 hour. Mean time to maximal concentration was 3 to 4 hours. At the higher dosages, serum total T4 concentration was high normal or above normal during most of the time after l-thyroxine administration, but serum concentration of total 3,5,3′-triiodothyronine did not remain within the normal range until the 44-μg/kg/d dosage was used. The customary dosage of 22 μg/kg/d (0.1 mg/10 lb/d) may not be adequate for most dogs. Pharmacokinetic variables appear to be highly dependent on the individual dog. Those with rapid absorption and higher concentration tended to have these characteristics at each dosage in this study. The pharmacokinetic variables, therefore, appear to be highly individualized, and dosages recommended for treatment of hypothyroidism should be considered to be only a starting point for the average dog. To avoid underdosing or overdosing, monitoring of treatment to adjust dose for individual dog kinetic variables seems to be imperative.
Effects of the 21-aminosteroid U-74389G on ischemia and reperfusion injury of the ascending colon in horses
Authors: Vatistas Nicholas J. , Snyder Jack R. , Hildebrand Susan V. , Harmon Faye A. , Woliner Michael J. , Henry Pegeen , Enos L. Reed , Magliano David , Brown Scott Anthony , Drake Christiana
Published: January 2024

Sixteen horses were allotted at random to 3 groups: vehicle only; low dosage (vehicle and 3 mg of U-74389G/kg of body weight); high dosage (vehicle and 10 mg of U-74389G/kg). These solutions were given prior to reperfusion. The ascending colon was subjected to 2 hours of ischemia followed by 2 hours of reperfusion. Before, during, and after ischemia, full-thickness colonic tissue biopsy specimens were obtained for measurement of malondealdehyde (mda) concentration and myeloperoxidase activity and for morphologic evaluation.

Although increases were not significant, mda concentration and myeloperoxidase activity increased during ischemia and reperfusion. Administration of U-74389G did not have significant effects on mda concentration and myeloperoxidase activity. However, the lower dosage tended (P = 0.08) to reduce myeloperoxidase activity at 30 and 60 minutes of reperfusion.

In horses of the vehicle-only group, ischemia induced a decrease in mucosal surface area that was continued into the reperfusion period (P ≤ 0.05). Administration of U-74389G at both dosages (3 and 10 mg/kg) prevented the reperfusion-induced reduction in mucosal surface area, which was significant at 60 minutes (high dosage; P = 0.05) and 90 minutes (low and high dosages; P = 0.02). After initial reduction in horses of all groups, mucosal volume increased for the initial 60 minutes of reperfusion.

Our results indicate that lipid peroxidation may be partially involved in continued cellular death after ischemia of the ascending colon of horses. The 21-aminosteroid, U-74389G, prevented further loss of mucosa and partially attenuated the induced increase in myeloperoxidase activity during reperfusion of the ascending colon.
Effect of cryoprecipitate and plasma on plasma von Willebrand factor multimeters and bleeding time in Doberman Pinschers with type-I von Willebrand's disease
Authors: Ching Yvonne N. L. H. , Meyers Kenneth M. , Brassard Jaqueline A. , Wardrop K. Jane
Published: January 2024

We determined whether administration of cry-oprecipitate or fresh-frozen plasma (ffp) would enhance glass bead platelet retention and shorten the bleeding time in von Willebrand factor (vWf)-deficient Doberman Pinschers. Plasma concentration of vWf was <15% of the reference value in these dogs and, on the basis of multimeric analysis of vWf, these dogs had type-I von Willebrand's disease (vWd). Concentration of vWf in cryoprecipitate (prepared from ffp of clinically normal dogs) was enriched almost 20 times, and the preparation was a concentrate of the largest and most physiologically active multimers. Administration of a dose of cryoprecipitate calculated to increase plasma vWf concentration of recipient dogs to 50 U/dl increased plasma vWf concentration in recipient dogs to about 40 U/dl. Mean buccal mucosal bleeding time (bmbt) shortened from 6.7 minutes before treatment to 3.8 minutes at 2 hours after treatment. Cryoprecipitate from donor dogs treated with deamino-8-d-arginine vasopressin (1 μg/ kg of body weight) effectively shortened mean bmbt from 6.4 minutes to 3.1 minutes. Administration of cryoprecipitate from vWf-deficient dogs prolonged, rather than shortened, the bmbt. After ffp (450 ml) infusion, plasma vWf concentration increased in recipient dogs, but the bmbt did not shorten. Glass bead platelet retention did not change after administration of cryoprecipitate or ffp. Thus, cryoprecipitate, especially from deamino-8-d-arginine vasopressin-treated donor dogs, is a concentrate of the most hemostatically active multimers of vWf and decreases the bmbt in dogs with vWd.
Secretagogue-induced [14C]aminopyrine uptake in isolated equine parietal cells
Authors: Campbell-Thompson Martha
Published: January 2024

Equine oxyntic mucosal cells were obtained by sequential exposure to pronase and collagenase. Acid production by parietal cells was assessed by uptake of [14C]aminopyrine (ap), a weak base that accumulates in intracellular acidic spaces. Incubation for various times revealed a maximal ap uptake at 10 minutes for histamine and carbachol. Similar secretagogue responses were observed for parietal cells from the mucosal cell preparation or after enrichment by elutriation. Histamine and isobutyl-methylxanthine (ibmx) stimulated AP uptake with a dose-dependent response and maximal effective concentration of 100 μM. Carbachol, 1 to 100 μM, and pentagastrin (pg), 1 to 1,000 μM, were ineffective stimulants of ap uptake. The ap uptake values for 100 μM ibmx, 1 μM carbachol, or 100 nM pg were 77 ± 6%, 50 ± 3-2%, and 40 ± 4.5%, respectively, of that observed with maximal stimulation by 100 μM histamine (mean ± sem, n = 4 to 14). Uptake of ap by nonstimulated control cells was 36 ± 3.6% of maximal histamine stimulation. The ap accumulations during control conditions and after stimulation with 100 μM histamine and IBMX, 1 μM carbachol, or 100 nM pg were 1.18 ± 0.39, 2.81 ± 0.85, 1.93 ± 0.48, 1.44 ± 0.36, and 1.23 ± 0.33 pmol of ap/105 parietal cells, respectively. Individual histamine dose-response curves were shifted to the right by increasing ranitidine and cimetidine concentrations (0.1 to 50 μM). These results indicate that isolated equine parietal cells are maximally stimulated by histamine and minimally stimulated by carbachol and pg.
Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage
Authors: Morris Elisabeth A. , Treadwell Benjamin V.
Published: January 2024

The effect of interleukin 1 (il-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of il-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to il-1 caused a decrease in total protein synthesis by 45, 68, and 87% after 1, 3, and 5 days, respectively, in culture while selectively inducing synthesis of the 57-kd neutral metalloproteinase stromelysin (matrix metallo-proteinase-3) in young and adult horses. Identification of stromelysin was confirmed by functional characterization and immunoprecipitation. Baseline total protein synthesis, as well as specific synthesis of stromelysin in cartilage from adult and aged horses, was markedly less than that of young horses. The il-1- induced reduction in total protein synthesis may not be a characteristic of equine articular cartilage from affected joints of horses with naturally acquired osteoarthritis as indicated by an overall increase in protein synthesis by osteoarthritic explants.

Introduction of il-1 into an equine articular cartilage explant culture system resulted in decrease of matrix component synthesis and increase in specific degradative enzyme synthesis and activity. Articular cartilage from aged horses had markedly less overall metabolic activity, compared with cartilage from young horses. Articular cartilage from affected joints of horses with naturally acquired osteoarthritis did not have metabolic alterations identical to those of il-1-stimulated normal articular cartilage from the same individual, necessitating reevaluation of the validity of the il-1-induced model of osteoarthritis. Osteoar thritis is a common, naturally acquired disease of horses, and tissue from animals of all ages and stages of osteoarthritis is available. The equine model of osteoarthritis may afford an important means of studying the alterations in articular cartilage metabolism as a function of age and disease severity.
Responses of the skin over the dorsum to sunlight in hairless descendants of Mexican hairless dogs
Authors: Kimura Tohru , Doi Kunio
Published: January 2024

Responses of the skin over the dorsum to solar uv irradiation (2 hours/d for 6 consecutive days) were investigated in hairless descendants of Mexican hairless dogs. Assessment of skin color changes, using a spectrophotometer, indicated that luminance values began to decrease from the third day of uv irradiation, reached the minimal value at 3 weeks, and almost recovered 12 weeks after completion of uv irradiation. The number of the dihydroxyphenylalanine-positive melanocytes increased significantly (P < 0.01) from the third day of uv irradiation, reached its maximal value at 2 weeks, and recovered to normal at 12 weeks after completion of uv irradiation. On the second day of uv irradiation, the epidermis became focally thick, with disarrangement of component cells that had degenerative changes. In addition, a few so-called sunburn cells with pyknotic nuclei were seen in the epidermis. On the third day of uv irradiation, apparent suntan reaction developed, and a large number of epithelial cells in the epidermis were heavily pigmented with melanin granules. At 12 weeks after completion of uv irradiation, the epidermis appeared almost normal. On the other hand, significant changes were not detected in the dermis throughout the study.
Efficacy of injectable abamectin against gastrointestinal tract nematodes and lungworms of cattle
Authors: Kaplan R. M. , Courtney C. H. , Kunkle W. E. , Zeng Q. Y. , Jernigan A. D. , Eagleson J. S.
Published: January 2024

Efficacy of abamectin against gastrointestinal tract nematodes and lungworms of cattle was determined in 4 experiments. The first 2 experiments were controlled trials in which efficacy was determined at necropsy in calves with either experimentally induced (n = 14) or naturally acquired (n = 16) infections. Half the calves in each experiment were treated with abamectin (200 μg/kg of body weight, sc), and half were left untreated as controls. Efficacy was > 99% against adult stages of Dictyocaulus viviparus, Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, Cooperia punctata, Trichuris discolor, and C oncophora, and was 92.4% against Nematodirus helvetianus. The second 2 experiments were clinical trials in which efficacy was determined by fecal egg count reduction in naturally infected yearling heifers (n = 75) or 2-year-old heifers (n = 75). Within replicates of 5, 4 heifers were assigned at random to treatment with 200 μg of abamectin/kg and 1 was left untreated as a control. Abamectin was 100% effective in eliminating strongylate nematode eggs from the feces of these heifers. In all experiments, adverse reactions were limited to small, clinically unimportant injection site swellings in 29% of abamectin treated calves. Abamectin was judged to be safe and effective in these trials.
Effects of zeranol implanted during a postweaning weight gain test on testicular, semen, and endocrine characteristics of bulls
Authors: Floyd James G. , Ott Randall S. , Hixon James E. , Veeramachaneni D. N. Rao , Willms Clifton L. , Parrett Douglas F.
Published: January 2024

At initiation of a 140-day postweaning weight gain test, Angus bulls were assigned in equal numbers (n = 5) to 1 of 3 treatment groups to determine effects of implantation with zeranol, an estrogenic growth promotant, on selected reproductive characteristics. The bulls, whose age (mean ± sd) was 233 ± 20 days at initiation of the test (day 0), were implanted with 36 mg of zeranol on day 0, on days 0 and 60, or were not implanted. At day 140, scrotal circumference and testicular consistency were unaffected by zeranol implantation. Zeranol implantation did not affect the morphologic characteristics of semen samples collected by electroejaculation on day 159. There was no effect of zeranol treatment on paired weights of testes, epididymides, or vesicular glands from bulls at slaughter 47 to 68 days after day 140. Microscopic lesions associated with estrogenic exposure were not observed in accessory sex glands or epididymides of any bull. Histopathologic changes in the seminiferous epithelium were not induced by zeranol treatment. Implantation with zeranol did not affect body weight or hip weight at day 140 or carcass weight at slaughter. Plasma concentration of luteinizing hormone was increased (P = 0.04), whereas testosterone concentration tended to be less (P = 0.08) in both groups of zeranol-implanted bulls after administration of gonadotropin-releasing hormone on day 140.
Predicting the number of herds infected with pseudorabies virus in the United States
Authors: Miller G. Y. , Forster D. L. , Tsai J. , Bech-Nielsen S.
Published: January 2024

Epidemiologic modeling of the likely herd-to-herd transmission of pseudorabies virus (prv) was developed to assess the progress and potential for the prv-eradication program in the United States. The herd-to-herd transmission of prv over a 20-year period (1993 to 2012) in the United States was simulated under various scenarios, which included variable program-funding levels and variable prevalences. A transition model (Markov process model) was used to predict yearly changes in herd prevalence of prv infection. Five mutually exclusive states of nature for herds were assumed: uninfected and not vaccinated; uninfected and vaccinated; known to be infected and not vaccinated; known to be infected and vaccinated; and infected, but not known to be infected. Three prevalences for states in the United States were assumed: higher prevalence, moderate prevalence, and lower prevalence. Three funding levels were assumed: no eradication program, continued funding at the current level, and increased funding of 25%. Estimates made by an expert panel for determining probabilities in the state-transition matrices were used. A model also was developed, and was considered to be the most optimistic scenario likely under increased funding of 25%. The most optimistic estimates of the probabilities that still lay within the range of estimates made by the expert panel were used for this model. Only the optimistic transmission matrices allowed for total eradication of prv. Using the optimistic matrices, all states in the United States of America had moved into the moderate- or low-level risk status by the year 2000. The longest time taken to achieve eradication was for the state of Iowa, where eradication was not achieved until 2012.
Administration of total parenteral nutrition in pigeons
Authors: Degernes Laurel , Davidson Gigi , Flammer Keven , Kolmstetter Christine , Munger Laddie
Published: January 2024

Venous access devices connected to jugular vein catheters were implanted sc in 2 groups of 6 White Carneau pigeons (Columba livia). Total parenteral nutrition (tpn), or a control solution (lactated Ringer's solution) was infused as a bolus 4 times daily. Physiologic, hematologic, and biochemical variables were monitored over 5 days. Complications in the TPN-treated pigeons included 8.7% weight loss during the 5-day trial, hyperglycemia for up to 90 minutes after infusion, and glucosuria after infusion. Control pigeons lost 1.3% of their body weight and did not become hyperglycemic or glucosuric after infusion. Hematocrit in both groups of pigeons decreased to a value slightly below published reference values for pigeons. Five pigeons developed venous thrombosis in the proximal part of the cranial vena cava. Results indicated that intermittent administration of tpn is possible in birds; however, further research is required to develop better techniques for administration of tpn solutions. Additionally, it is important to determine, more specifically, the caloric and nutrient requirements of pigeons under stress and receiving tpn.
Bluetongue virus infection in pregnant ewes
Authors: Parsonson Ian M. , Luedke Albert J. , Barber Thomas L. , Walton Thomas E.
Published: January 2024

Inoculation of 53 ewes after 35, 45, 60, or 80 days of gestation with bluetongue virus serotypes 10, 11, 13, or 17, or with epizootic hemorrhagic disease virus serotypes 1 or 2, resulted in overt clinical disease in the 47 ewes inoculated with bluetongue virus but not in the 6 ewes inoculated with epizootic hemorrhagic disease virus. None of the lambs produced by these ewes had developmental defects or any evidence of persistence of viremia.
Disposition of penicillin G after administration of benzathine penicillin G, or a combination of benzathine penicillin G and procaine penicillin G in cattle
Authors: Papich Mark G. , Korsrud Gary O. , Boison Joe O. , Yates W. D. G. , MacNeil J. D. , Janzen E. D. , McKinnon J. J. , Landry D. A.
Published: January 2024

Plasma concentration of penicillin G was evaluated in beef steers after administration of either a combination of benzathine penicillin G and procaine penicillin G in a 1:1 mixture at a dosage of 9,000 U/kg of body weight, im (n = 5), 24,000 U/kg, im (n = 5), or 8,800 U/kg, sc (n = 5), or benzathine penicillin G alone at a dosage of 12,000 U/kg, im (n = 7). Plasma concentration of penicillin G was measured by use of a high-performance liquid chromatography assay that had a limit of determination of 0.005 µg/ml. At a dosage for this combination of 9,000 U/kg im, and 8,800 U/kg, sc, which are approved label recommendations in Canada, and the United States, respectively, mean (± sem) peak plasma concentration was 0.58 (± 0.15) and 0.44 (± 0.02) µg/ml, respectively. Although plasma penicillin concentration was quantifiable for 7 days in the steers that received 9,000 U/kg, im, and for 4 days in the steers that received 8,800 U/kg, sc, the concentration was < 0.1 µg/ml in both groups after the first 12 hours. After administration of the combination at dosage of 24,000 U/kg, im, there was an initial peak plasma concentration at approximately 2 hours; thereafter, plasma concentration decreased slowly, with half-life of 58 hours. Although plasma penicillin G concentration was quantifiable for 12 days at this dosage, concentration was < 0.1 µg/ml after the first 48 hours. After the initial 48 hours, plasma concentration of penicillin was of similar magnitude and decreased at similar rate for the combination at dosage of 24,000 U/kg and for 12,000 U/kg of benzathine penicillin G alone. Most of the plasma penicillin G concentration in the first 24 hours after administration of a 1:1 combination of benzathine penicillin G and procaine penicillin G is attributable to absorption of procaine penicillin G. After the first 48 hours, most of the plasma drug concentration appeared to be produced by absorption of penicillin G from benzathine penicillin G. Absorption of benzathine penicillin G produces quantifiable plasma penicillin G concentrations for several days, but they are below the level of susceptibility for most bacteria.
Clinical efficacy and toxicity of doxorubicin encapsulated in glutaraldehyde-treated erythrocytes administered to dogs with lymphosarcoma
Authors: Matherne Curt M. , Satterfield William C. , Gasparini Anna , Tonetti Michela , Astroff A. Barry , Schmidt Russell D. , Rowe Loyd D. , DeLoach John R.
Published: January 2024

Doxorubicin was encapsulated in canine erythrocytes, treated with 0.32% glutaraldehyde, and administered at a dosage equivalent to 30 mg of free doxorubicin/m2 of body surface area to dogs with diagnosis of lymphosarcoma. Compared with administration of free doxorubicin, this method of drug delivery substantially reduced peak plasma concentration and prolonged higher plasma concentration of doxorubicin. As such, this method was comparable to continuous iv infusion. Previous studies have indicated this method’s potential for reduction in toxic side effects, particularly cardiotoxicosis, while allowing higher total doses of doxorubicin to be administered. In this study, doxorubicin encapsulated in glutaraldehyde-treated erythrocytes induced a triphasic exponential decay of doxorubicin from plasma, the highest relative contribution to the total area of the curve being the terminal phase. The treatment was effective in inducing complete and partial remissions of lymphosarcoma, with minimal acute toxicosis and no evidence of cardiotoxicosis. However, substantial, unanticipated, chronic, nonregenerative myelosuppression developed, and was most strikingly expressed as profound thrombocytopenia. Efforts to ameliorate or circumvent this toxic effect will be required prior to further consideration of this doxorubicin delivery system for treatment of systemic neoplasia.
Cutaneous delayed hypersensitivity reactions of cattle vaccinated with mutant strains of Brucella abortus, using brucellins prepared from various brucellar strains
Authors: Cheville Norman F. , Jensen Allen E. , Morfitt David C. , Stabel Thomas J.
Published: January 2024

Cutaneous reactivity to brucellin was evaluated in 10-month-old heifers vaccinated with low-virulence mutant strains of Brucella abortus and was compared with brucellin reactions in postparturient cows with active brucellosis. In the cows, the cutaneous lesion was characterized microscopically as severe, acute, serofibrinous vasculitis; dermal lesions at 6, 12, 25, and 48 hours after brucellin injection consisted of endothelial activation and perivascular exudation that led to progressive accumulation of fibrin, monocytes, macrophages, and lymphocytes. In vaccinated heifers, cutaneous tests were done, using standard brucellin, brucellin prepared from strain RB51, and the purified brucellar proteins-31K and superoxide dismutase. Negative-control cattle given saline solution, did not have cutaneous reactions. Standard brucellin induced the most marked reactions in vaccinated heifers. Brucellin from rough strain RB51 caused positive reactions in heifers vaccinated with strain 19, but reactions were variable in other groups. Skin lesions induced by purified superoxide dismutase and 31-kd proteins in vaccinated cattle were not acceptable for diagnosis. Marked variability of test responses in vaccinated cattle precludes field use of this test to determine vaccination status.