bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of an orally administered vaccine, using hydrogels containing bacterial exotoxins of Pasteurella haemolytica, in cattle
Authors: Bowersock Terry L. , Shalaby Waleed S.W. , Levy Michel , Samuels Myra L. , Lallone Roger , White M. Randy , Borie Della L. , Lehmeyer Joyce , Park Kinam
Published: January 2024

Poly(methacrylic acid) hydrogels were tested for oral delivery of a vaccine against Pasteurella haemolytica infection in cattle. Culture supernatants of P haemolytica, the most common bacterium associated with pneumonia in cattle, were used as the antigens in the vaccine. Hydrogels containing culture supernatants were administered orally to calves. Calves were then challenge-exposed with virulent P haemolytica. Calves were euthanatized 3 days after challenge exposure. The lungs of each calf were scored for severity and size of pneumonic lesions. Results indicated that vaccinated calves had smaller, less severe pneumonic lesions and lived longer than nonvaccinated calves. These results indicated that hydrogels can be used to deliver vaccines orally to calves to enhance resistance to pneumonia caused by P haemolytica.
Cardiorespiratory effects of induction and maintenance of anesthesia with ketamine-midazolam combination, with and without prior administration of butorphanol or oxymorphone
Authors: Jacobson John D. , McGrath Charles J. , Smith Eric P.
Published: January 2024

Cardiorespiratory effects of an iv administered bolus of ketamine (7.5 mg/kg of body weight) and midazolam (0.375 mg/kg) followed by iv infusion of ketamine (200 μg/kg/min) and midazolam (10 μg/kg/min) for 60 minutes was determined in 6 dogs. Ketamine-midazolam combination was administered to dogs on 3 occasions to determine effects of prior administration of iv administered saline solution (1 ml), butorphanol (0.2 mg/kg), or oxymorphone (0.1 mg/kg). The infusion rate of ketamine and midazolam was decreased by 25% for anesthetic maintenance after opioid administration.

There were no significant differences in cardiorespiratory variables after saline solution or butorphanol administration; however, oxymorphone caused significant (P < 0.05) increases in mean arterial blood pressure, systemic vascular resistance, and breathing rate. Bolus administration of ketamine-midazolam combination after saline solution caused significant (P < 0.05) increases in heart rate, mean arterial blood pressure, cardiac index, mean pulmonary blood pressure, venous admixture, and significant decreases in stroke index, pulmonary capillary wedge pressure, arterial and mixed venous oxygen tension, arterial oxygen content, and alveolar-arterial oxygen gradient. Opioid administration was associated with significantly (P < 0.05) lower values than was saline administration for heart rate, mean arterial blood pressure, and arterial and mixed venous pH and with higher values for stroke index, pulmonary capillary wedge pressure, and arterial and mixed venous carbon dioxide tension. Prior oxymorphone administration resulted in the highest (P < 0.05) values for mean pulmonary blood pressure, venous admixture, and arterial and mixed venous carbon dioxide tension, and the lowest values for arterial oxygen tension, and arterial and mixed venous pH. Each treatment provided otherwise uncomplicated anesthetic induction, maintenance, and recovery. Time to extubation, sternal recumbency, and walking with minimal ataxia was similar for each treatment.
Effect of anticoagulant and blood storage time on platelet-bound antibody concentrations in clinically normal dogs
Authors: Lewis David C. , Meyers Kenneth M.
Published: January 2024

A solid-phase elisa to detect antibodies bound to the surface of canine platelets (platelet-bound antibodies) is described. Using this assay, the effect of anticoagulant and storage time of anticoagulant blood on the concentration of antibodies bound to the surface of platelets from clinically normal dogs was investigated. Blood from 3 clinically normal dogs was anticoagulated with acid citrate dextrose, Na3 citrate, and aqueous K3 edta and stored on ice for up to 48 hours. Platelet-bound antibody concentration was measured on platelets isolated from anticoagulated blood immediately after venipuncture and subsequent to storage of blood for 24 and 48 hours. Differences in platelet-bound antibody concentrations were investigated among dogs, anticoagulants, and storage times by anova and Bonferroni pair-wise comparison of means. There was no effect of dog on platelet-bound antibody concentration. The effect of time was significant (P < 0.0001), with higher concentration of platelet-bound antibodies detected with increasing storage time. Effect of anticoagulant on platelet-bound antibody concentration was not statistically significant; however, there was a trend to increasing concentration of antibodies bound to platelets isolated from Na3 citrate- and K3 edta-anticoagulated blood. Moreover, there was significant (P = 0.02) interaction between anticoagulant and time. Platelet-bound antibody concentration increased with storage of anticoagulated blood prior to platelet isolation and with use of Na3 citrate and K3 edta anticoagulants. The preferred anticoagulant for platelet-bound antibody measurement is acid citrate dextrose. Platelet-bound antibody concentration should be determined not longer than 24 hours after blood collection.
Treatment of group E streptococci-induced lymphadenitis in swine by feeding various concentrations of chlortetracycline: Relation of antibody with prevalence of abscesses
Authors: Olson LeRoy D. , Miller Robert B. , Schlink Gerald T.
Published: January 2024

Consumption of chlortetracycline (ctc) at concentration of 220 mg/kg of feed for 4 weeks in experiment 1 and at concentrations of 110 and 220 mg/kg for 3 weeks and 440 mg/kg for 2 weeks in experiment 2 failed to eliminate streptococci-induced lymphadenitis from swine referred to as principals. Abscesses, mostly in the head and neck, developed in at least a third of all swine in the various groups fed these ctc concentrations. Feeding of 220 mg of ctc/kg of feed in experiment 1 began 12 weeks after exposure of principals to an untypeable group E streptococci (ges; isolate 3X29A). In experiment 2, feeding of 110 and 220 mg of ctc/kg of feed began 5 weeks after exposure of principals to ges and feeding of 440 mg of ctc/kg of feed began 6 weeks after exposure. One or more cohabitating sentinel swine of experiment 1 and one or more sentinels in all groups of principals of experiment 2, except group 2, developed abscesses that were mostly in the head and neck. In experiment 2, correlation between serum GES antibody titer and development of one or more abscesses in the principals was highly significant (P < 0.01); however, correlation between antibody titer and abscesses in the sentinels only approached significance (P < 0.10).
Effectiveness of doramectin for treatment of experimentally induced gastrointestinal tract larval nematode infections in calves
Authors: Yazwinski T. A. , Featherston H. , Tucker C.
Published: January 2024

Anthelmintic efficacy of doramectin, a macrocyclic lactone of the avermectin family, was evaluated against larval parasitic nematodes in calves. The investigational product was given sc at a dosage of 0.2 mg/kg of body weight to 10 calves infected 6 days previously with third-stage larvae of the genera Haemonchus, Ostertagia, Cooperia, and Nematodirus. Ten additional calves with identical larval exposure were given saline solution sc also at 6 days after inoculation, and served as the nonmedicated controls. At 14 or 15 days after treatment, the calves were slaughtered in complete replicate for nematode recovery and subsequent quantifications. In comparing nematode numbers at necropsy for the saline- and dora-mectin-treated groups, nematocidal effectiveness as directed against fourth-stage larvae was: 100% for Haemonchus placei and Cooperia spp, > 99% for Ostertagia ostertagi, and 64.5% for Nematodirus helvetianus. All treatments were easily administered, and adverse behavioral or tissue reactions were not seen to result from doramectin administration.
Effects of parathyroid hormone depletion in dogs with induced renal failure
Authors: Finco Delmar R. , Brown Scott A. , Cooper Tanya , Crowell Wayne A. , Hoenig Margarethe , Barsanti Jeanne A.
Published: January 2024

Six parathyroidectomized (ptx) and 6 control dogs had renal mass reduced by 15/16, and were studied for effects of parathyroid hormone depletion on progression of renal failure. All ptx dogs and 4 of 6 control dogs survived until necropsy after 32 weeks.

Plasma parathyroid hormone concentration was undetectable in ptx dogs throughout the study, but was greater than normal in control dogs. Serum inorganic phosphate (P) concentration was increased in ptx dogs (6.8 ±0.1 mg/dl) and in control dogs (7.5 ± 0.2), but did not differ significantly (P = 0.254) between groups. Ionized blood calcium values (Ca2+) were significantly (P = 0.014) lower in ptx dogs (1.31 ± 0.01 mmol/L) than in control dogs (1.36 ± 0.00 mmol/L), but were more variable in ptx dogs.

Values in ptx dogs were not significantly different from those in control dogs for glomerular filtration rate (P = 0.914), plasma creatinine concentration (P = 0.903), and urine protein to creatinine ratio (P = 0.756) determined at intervals during the study. Terminal glucose tolerance and plasma insulin concentrations, P tolerance, and renal P excretion did not differ between groups.

Histologic comparison of kidneys removed during reduction of renal mass with kidneys removed at necropsy revealed development of lesions in both groups of dogs, and no protective effect from parathyroidectomy.

Mineral analysis of aorta, brain, heart, lungs, and skeletal muscle obtained at necropsy revealed no significant difference between ptx and control groups. Renal cortical calcium concentration was significantly (P < 0.05) greater in kidneys obtained at necropsy than in kidneys obtained during nephrectomy, but ptx did not protect renal cortex from calcium deposition.
Effects of choreito consumption on struvite crystal growth in urine of cats
Authors: Buffington C. A. , Blaisdell Jean L. , Komatsu Yasuhiro , Kawase Kiyoshi
Published: January 2024

The effect of a dietary supplement, choreito, on in vitro struvite crystal growth in feline urine was evaluated. Adult specific-pathogen-free cats (4 females, 4 males) considered to be clinically normal on the basis of physical examination findings and normal results of cbc, serum biochemical analyses, and urinalyses obtained before the beginning of the study were used. Before 24-hour urine sample collections were made, cats were fed a commercial canned diet with 0 or 500 mg of choreito supplement/kg of body weight for at least 2 weeks in a cross-over design with 4 cats/treatment. Filtered urine samples were analyzed for urine pH, specific gravity, osmolality, and urine electrolytes. The struvite activity product was calculated, using a statistical software program that calculates urine saturation. Urine samples were placed in wells of cell culture plates, increasing concentrations of ammonium hydroxide were added to adjacent wells to stimulate struvite crystal growth, and the plates were incubated at 37 C. Crystal growth was assessed by determination of number of crystals and supersaturation index by direct visualization, using an inverted microscope. Supplementation of the diet with choreito (at this concentration) did not change urine pH, specific gravity, osmolality, urine electrolyte composition, or calculated struvite activity product. However, supplementation significantly (P < 0.05) reduced crystal number and supersaturation index. These results indicate that direct observation of struvite crystal formation in whole urine may more accurately predict the effects of treatments to prevent or treat struvite urolithiasis than do calculations based on electrolyte concentration that do not account for the effect of urine macromolecules. It also may mean that choreito consumption affects the concentration of inhibitors or promoters in urine. It was concluded that choreito significantly (P < 0.05) reduced growth of struvite crystals in feline urine, and thus may have a role in prevention of feline struvite urolithiasis. In vivo studies will be necessary to test this hypothesis.
Effect of bacterial lipopolysaccharides on sulfated glycosaminoglycan metabolism and prostaglandin E2 synthesis in equine cartilage explant cultures
Authors: MacDonald Melinda H. , Stover Susan M. , Willits Neil H. , Benton Hilary P.
Published: January 2024

The metabolic responses of equine articular cartilage to incubation with bacterial lipopolysaccharide (lps) were studied, using explant cultures of articular cartilage obtained from the metatarsophalangeal joints of 15 horses, age of which ranged from 3 months to 20 years. For comparison, explants were also established from the metatarsophalangeal joints of 3 calves. Explants were cultured for 3 days in medium containing various concentrations of lps from 0 (control) to 100 μg/ml. Glycosaminoglycan (gag) released during the 3-day incubation was determined by a spectrophotometric assay, using the dye 1,9-di-methylmethylene blue. Newly synthesized gag content was assayed by measuring [35S]sulfate incorporation during a 3-hour pulse labeling period. In addition, prostaglandin E2 (pge2) synthesis was quantified, using a [3H]pge2 radioimmunoassay kit and magnetic separation. Finally, explants from 3 animals were used to evaluate the effect of supplementing culture medium with 5% serum on the response of explants to lps, and explants from 1 horse were used to compare responses to stimulation with lps derived from 2 bacterial sources.

Equine explants cultured with bacterial lps had a dose-dependent decrease in synthesis and increase in release of gag, and these responses were significantly (P < 0.0001) greater in explants from younger horses. In addition, equine explants had a significant (P = 0.0001) dose-dependent increase in concentration of pge2 released into the culture medium in response to incubation with lps.

Comparison of data for gag synthesis from equine and bovine explants revealed a significant (P = 0.025) difference in responsiveness to lps between the 2 species. Equine explants tended to have a greater suppression of gag synthesis in response to incubation with increasing concentrations of lps than did age-corrected bovine samples. However, similar analysis of data on gag release did not indicate any difference in sensitivity between the 2 species for this response. There was no evidence that the presence or absence of serum supplementation or the use of lps derived from different bacterial sources made a significant difference in the response of explants to incubation with lps.
Comparison of humoral immunity and induction of proliferating T lymphocytes in vaccinia virus-infected rabbits and rhesus macaques
Authors: Schäffner Jörg-Wolfgang , Dittmer Ulf , Otteken Ahlert , Coulibaly Cheik , Bodemer Walter , Voss Gerald , Hunsmann Gerhard
Published: January 2024

Vaccina virus (VV) infection induces specific antibodies and cytotoxic T cells in various animal species. Therefore, helper T cells also should be induced that stimulate the humoral and cellular immune responses. We determined such helper T-cell activity in 2 species after VV infection. Rabbits and rhesus macaques were infected with the Copenhagen strain of VV or with recombinant VV expressing retroviral proteins. Animals of both species developed antibodies and specific proliferative T-cell response. This reactivity could be enhanced by booster infection with VV. The proliferating macaque cells were CD4+ and major histocompatability complex class Il-restricted. These data confirm the broad immunogenicity of VV. Expression of additional polypeptides expressed from a recombinant VV does not lead to altered immune response to VV antigens. However, strength of the helper T-cell response, as well as clinical reactions, differed between macaques and rabbits. Infection with recombinant VV as delivery vectors offers the opportunity for combined vaccination against recombinant proteins and does not diminish cellular and humoral immune responses to VV itself.
Histopathologic evidence of reperfusion injury in the large colon of horses after low-flow ischemia
Authors: Moore Rustin M. , Bertone Alicia L. , Muir William W. , Stromberg Paul C. , Beard Warren L.
Published: January 2024

Effects of low-flow ischemia and reperfusion of the large colon on mucosal architecture were determined in horses. Twenty-four adult horses were randomly allocated to 3 groups: sham-operated (n = 6), 6 hours of ischemia (n = 9), and 3 hours of ischemia and 3 hours of reperfusion (n = 9). Low-flow ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline values. Systemic hemodynamic and metabolic variables were maintained constant and in a normal physiologic range. Full-thickness biopsy specimens were obtained from the left ventral colon for histomorphologic and morphometric examination at baseline and at 30-minute intervals for 6 hours; additional biopsy specimens were collected at 185, 190, and 195 minutes (corresponding to 5-, 10-, and 15-minute periods of reperfusion in group-3 horses). There were no differences among groups at baseline or across time in group-1 horses for any of the histopathologic variables. There were significant (P < 0.05) increases in percentage of surface mucosal disruption, estimated and measured percentage depth of mucosal loss, mucosal hemorrhage, mucosal edema, and cellular debris index during 0 hour to 3 hours, compared with baseline, and from 3 hours to 6 hours, compared with 3 hours in horses of groups 2 and 3. Estimated percentage depth of mucosal loss and cellular debris index were significantly (P < 0.05) greater in group-3 horses, compared with group-2 horses during the interval from 3 to 6 hours. There were trends toward greater percentage of surface mucosal disruption and mucosal edema during the early phase of reperfusion (3 to 4 hours) and greater mucosal hemorrhage, measured percentage depth of mucosal loss, and mucosal interstitial-to-crypt ratio during the late phase (4 to 6 hours) of reperfusion in group-3 horses vs group-2 horses. Reestablishment of colonic arterial blood flow after low-flow ischemia caused greater mucosal injury than did a comparable period of continued ischemia. Thus, reperfusion injury was detected in the large colon of horses after low-flow arterial ischemia. The serial mucosal alterations that developed in the colon were comparable in horses of groups 2 and 3; however, reperfusion exacerbated colonic mucosal injury.
Androgen receptors in the pelvic diaphragm muscles of dogs with and without perineal hernia
Authors: Mann F. A. , Nonneman D. J. , Pope E. R. , Boothe H. W. , Welshons W. V. , Ganjam V. K.
Published: January 2024

Levator ani and coccygeus muscle estrogen and androgen receptors were measured in 6, healthy, ≥ 5-year-old, noncastrated, male Beagles (controls) and in 24 dogs with perineal hernia. Estrogen and androgen receptor analyses were performed on levator ani and coccygeus muscle specimens obtained from control dogs at the time of castration; contralateral levator ani and coccygeus muscle specimens were assayed 2 months after castration. During herniorrhaphy of dogs with perineal hernia, levator ani (non-castrated, n = 12; castrated, n = 7) and/orcoccygeus (noncastrated, n = 5; castrated, n = 4) muscle biopsy specimens were obtained for estrogen and androgen receptor analyses. For estrogen and androgen receptor assays, each muscle biopsy specimen was homogenized in Tris-edta-glycerol buffer, and centrifuged at 30,000 × g; extracts were used for binding with ligands: [3H]methyltrienolone (H-R1881) for androgen receptors, and [3H] estradiol-17β for estrogen receptors. Extracts were incubated overnight at 0 to 4 C. Nonspecific binding was estimated, using 100-fold concentration of cold ligands. Bound and free hormones were separated, using hydroxylapatite batch assay. Receptor numbers for each tissue were calculated as femtomoles (fmol) per milligram of protein. Quantified data were compared between precastration and postcastration controls, using a paired t-test. One-way anova and Bonferroni post-hoc test were used to compare values for precastration controls, postcastration controls, castrated dogs with perineal hernia, and noncastrated dogs with perineal hernia. Significance was set at P < 0.05.

Estrogen receptors were not detected. Androgen receptors were characterized by Scatchard analysis (dissociation constant = 3.16 to 6.6 nM R1881, receptor number = 23 to 175 fmol/mg of protein). Postcastration controls had significantly higher numbers of androgen receptors in levator ani and coccygeus muscles than did precastration controls. Dogs with perineal hernia (castrated and noncastrated) had lower numbers of androgen receptors than did either control group. The paucity of androgen receptors in pelvic diaphragm muscles of dogs with perineal hernia, compared with controls, suggests that decreases in quantity of androgen receptors contribute to the etiopathogenesis of perineal hernia in dogs.
Influence of four diets containing approximately 11% protein (dry weight) on uric acid, sodium urate, and ammonium urate urine activity product ratios of healthy Beagles
Authors: Bartges Joseph W. , Osborne Carl A. , Felice Lawrence J. , Allen Timothy A. , Brown Charles , Koehler Lori A. , Bird Kathy A. , Unger Lisa K. , Chen Menglan
Published: January 2024

Urine activity product ratios of uric acid (aprua), sodium urate (aprna), and ammonium urate (aprau), and urinary excretion of 10 metabolites were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of consumption of 4 diets containing approximately 11% protein (dry weight) and various protein sources: a 72% moisture, casein-based diet; a 10% moisture, egg-based diet; a 72% moisture, chicken-based diet; and a 71% moisture, chicken-based, liver-flavored diet. Significantly (P < 0.05) higher aprua, aprna, and aprau were observed when dogs consumed the egg-based diet, compared with the other 3 diets; there were no differences in these ratios among the other 3 diets.

Twenty-four-hour urinary excretions of chloride, potassium, phosphorus, and oxalic acid were significantly (P < 0.05) higher when dogs consumed the egg-based diet. Twenty-four-hour urinary excretions of sodium were significantly (P < 0.05) higher when dogs consumed the egg-based diet, compared with the casein-based diet and the chicken-based, liver-flavored diet, but were not significantly different between the egg-based diet and chicken-based diet. Twenty-four-hour urine volume was similar when dogs consumed the 4 diets. Twenty-four-hour endogenous creatinine clearance was significantly (P < 0.05 lower when dogs consumed the casein based diet there were no differences among the other 3 diets. Although consumption all diets was associated with production alkaline urine, the 24-hour urine pH was significantly (P < 0.05) higher when dogs consumed the egg-based diet.

These results suggest that use diets containing approximately 10.5% protein (dry weight) and 70 moisture protocols designed for dissolution and prevention urate uroliths may be beneficial. The source dietary protein in canned formulated diets does not appear significantly influence the saturation of urine with uric acid, sodium urate, or ammonium urate.
Cortical bone concentrations of enrofloxacin in dogs
Authors: Duval Julie M. , Budsberg Steven C.
Published: January 2024

Cortical bone concentrations of enrofloxacin were determined over time in dogs after sc administration of the drug. Nineteen healthy adult dogs were anesthetized and were given 2.5 or 5.0 mg of enrofloxacin/kg of body weight, sc. Serial serum and bone samples were obtained for determination of enrofloxacin concentrations at intervals until 8 hours after drug administration. Cortical bone samples were procured by surgical disarticulation of successive second phalanges. Additional cortical bone samples were taken from long bones in 4 dogs. Mean ± sd peak serum enrofloxacin concentration was 0.54 ± 0.10 μg/ml for the 2.5-mg/kg dosage and 0.97 ± 0.34 μg/ml for the 5.0-mg/kg dosage. Serum concentration was significantly higher than bone concentration for each dosage. Mean peak bone concentrations reached 29% of peak serum values: 0.15 ± 0.09 μg/g and 0.29 ± 0.09 μg/g for 2.5-mg/kg and 5.0-mg/kg dosages, respectively. Serum concentration for the 5.0-mg/kg dosage was significantly greater than that for the 2.5-mg/kg dosage for all times, whereas bone concentrations for the 5.0-mg/kg dosage were significantly higher at all times after 180 minutes. For the duration of the study, cortical bone concentrations of enrofloxacin at either dosage exceeded the minimum inhibitory concentration (mic) for the Enterobacteriaceae, but reliably exceeded the mic for Staphylococcus sp only at the 5.0-mg/kg dosage. At no time did cortical bone concentrations of enrofloxacin exceed the mic for Pseudomonas aeruginosa at either dosage.

To validate extrapolation of data from the second phalanx to long bones and from anesthetized to awake dogs, 16 healthy dogs being euthanatized in unrelated studies were given 2.5 or 5.0 mg of enrofloxacin/kg, sc. These dogs were not anesthetized but were euthanatized at 60, 120, or 240 minutes after drug administration, and multiple cortical bone samples were taken. Antibiotic concentrations in the second phalanx were not significantly different from those in long bones. Comparison of enrofloxacin concentrations in cortical bone of awake and anesthetized dogs suggested no differences between groups. We concluded that general anesthesia and use of the antibiotic concentrations in the second phalanx as representative of those in long bones did not affect results of this study.
Cannulation of a lateral ventricle in the brain of Holstein calves
Authors: Ames N. Kent , Tucker H. Allen , Chapin Larry T. , Gaynor Paula J.
Published: January 2024

A surgical technique was developed for implanting a flexible polyurethane cannula in a lateral ventricle in the brain of calves. Initially, measurements were made on 25 calves at necropsy to develop equations for calculating coordinates for cannula placement. The distance (cm) caudal, in the sagittal plane, from the coronal suture line to the center of a hole to be drilled in the parietal bone of the skull was: 0.73 + (0.00925 × body weight [kg]). The distance (cm) lateral from the midline to the center of the hole to be drilled was: 0.018 + (0.6464 × distance caudal). The depth (cm) from the surface of the skull to the dorsal surface of the lateral ventricle was: 2.29 + (0.0159 × body weight [kg]). Surgery was subsequently performed on 17 calves. A 5-mm-diameter hole was drilled through the skull with a hand trephine at coordinates derived from the aforementioned regression equations. A polyurethane cannula (total length, 30 cm; 1 mm id; 2 mm od) covering a stainless-steel 20-gauge blunt-tipped needle (stylet) was lowered through the brain and into a lateral ventricle at an angle of 20.5° relative to the frontal bones of the skull. The blunt-tipped needle was then removed, and csf was allowed to drip from the cannula to verify placement. One stainless-steel screw was inserted 0.6 cm medial, and another was inserted 0.6 cm caudal to the hole in the skull. The area around the cannula, bone screws, and hole in the skull was covered with dental acrylic (approx 2 cm in diameter) to stabilize the cannula. With minimal restraint of calves, injection of substances into and withdrawal of csf from a lateral ventricle of the brain were possible in most calves for at least 6 weeks after surgery was performed.
Myocardial edema and compromised left ventricular function attributable to dirofilariasis and cardiopulmonary bypass in dogs
Authors: Rohn Douglas A. , Davis Karen L. , Mehlhom Uwe , Allen Steven J. , Laine Glen A.
Published: January 2024

We investigated the relation between left ventricular dysfunction and myocardial edema in dogs with heartworm (Dirofilaria immitis) infection that were undergoing cardiopulmonary bypass. Dogs with and without D immitis were anesthetized by continuous thiopental infusion and were mechanically ventilated. Sonomicrometry crystals were placed on the long and short axes of the left ventricle, and a Millar pressure transducer was placed in the left ventricular chamber. Pressure-volume loops were digitized and continuously recorded. Dogs with and without D immitis were placed on standard hypothermic cardiopulmonary bypass, with 1 hour of aortic cross-clamp. Wet-to-dry weight ratio corrected for residual blood volume was used to quantitate the volume of myocardial edema. Preload recruitable stroke work was used as a preload-independent index of systolic function. Tau, the isovolumic relaxation time constant, was determined to assess diastolic relaxation. Dogs with D immitis had increased baseline myocardial wet-to-dry weight ratio. After cardiopulmonary bypass, myocardial edema increased in all dogs. Acute edema attributable to cardiopulmonary bypass decreased preload recruitable stroke work in all dogs of both groups, and dogs with D immitis could not be weaned from cardiopulmonary bypass. Myocardial edema increased diastolic relaxation times (τ) in dogs with and without D immitis. We conclude that cardiopulmonary bypass and heartworm infection induce myocardial edema. This edema compromises left ventricular systolic and diastolic function making D immitis an important confounding factor in weaning dogs from cardiopulmonary bypass.
Diaphyseal structural properties of equine long bones
Authors: Hanson Peter D. , Markel Mark D. , Vanderby Ray
Published: January 2024

We evaluated the single-cycle structural properties for axial compression, torsion, and 4-point bending with a central load applied to the caudal or lateral surface of a diaphyseal segment from the normal adult equine humerus, radius, third metacarpal bone, femur, tibia, and third metatarsal bone. Stiffness values were determined from load-deformation curves for each bone and test mode. Compressive stiffness ranged from a low of 2,690 N/mm for the humerus to a high of 5,670 N/mm for the femur. Torsional stiffness ranged from 558 N · m/rad for the third metacarpal bone to 2,080 N · m/rad for the femur. Nondestructive 4-point bending stiffness ranged from 3,540 N · m/rad for the radius to 11,500 N · m/rad for the third metatarsal bone. For the humerus, radius, and tibia, there was no significant difference in stiffness between having the central load applied to the caudal or lateral surface. For the third metacarpal and metatarsal bones, stiffness was significantly (P < 0.05) greater with the central load applied to the lateral surface than the palmar or plantar surface. For the femur, bones were significantly (P < 0.05) stiffer with the central load applied to the caudal surface than the lateral surface. Four-point bending to failure load-deformation curves had a bilinear pattern in some instances, consisting of a linear region at lower bending moments that corresponded to stiffness values from the nondestructive tests and a second linear region at higher bending moments that had greater stiffness values. Stiffness values from the second linear region ranged from 4,420 N · m/rad for the humerus to 13,000 N · m/rad for the third metatarsal bone. Differences in stiffness between nondestructive tests and the second linear region of destructive tests were significant (P < 0.05) for the radius, third metacarpal bone, and third metatarsal bone. Difference between stiffness values of paired left and right bones was not detected for any test. Four-point bending ultimate failure bending moments ranged from 260 N · m for the femur to 940 N · m for the third metatarsal bone. There was no difference in failure bending moment between the directions of applied central load for a given bone.
Effect of deferoxamine and hyperbaric oxygen on free, autogenous, full-thickness skin grafts in dogs
Authors: Hosgood Giselle , Hodgin E. Clay , Strain George M. , Lopez Mae K. , Lewis Daniel D.
Published: January 2024

Free, autogenous, full-thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (def-hes; 50 mg/kg of body weight, iv), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (hes) in 0.9% saline solution (5 ml/kg, iv). All dogs (def-hes/hbo- and hes/hbo-treated) were exposed to 60 minutes of hyperbaric oxygen (hbo) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in hes/hbo-treated dogs (mean ± sd, 13.3 ± 21.3%; median, 3.0%) than in def-hes/hbo-treated dogs (64.7 ± 39.2%; 88.3%; P = 0.095, Mann-Whitney two-tailed test). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs (r = 0.91) and for hes/hbo-treated dogs (r = 0.97). The def-hes/hbo-treated dogs had less consistent correlation (r = 0.67). Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of def-hes/hbo-treated dogs. These cells were also observed in the dermis, but not subcutaneous tissue of the control skin sections, and in some viscera of def-hes/hbo-treated dogs. Deferoxamine appears to attenuate the detrimental effect of hbo and hes on survival of free skin grafts. However, clinical use of hbo is not recommended as adjunct treatment for free skin grafts in dogs in the first 10 days after grafting. Administration of def-hes is not recommended because it has failed to improve the survival of free skin grafts, and the consequence of the cellular response seen in this study is undetermined.
Arrhythmia prevalence during ambulatory electrocardiographic monitoring of Beagles
Authors: Ulloa Herman M. , Houston Barry J. , Altrogge Douglas M.
Published: January 2024

Ambulatory ecg, approximately 18 to 24 hours in duration, were obtained from 113 male and 115 female clinically normal, purpose-bred Beagles. The ecg analyzed semi-automatically (44 males, 46 females) were evaluated for heart rate, ventricular ectopic complexes (vec), bradycardia, and sinus pause; those analyzed by visual inspection (69 males, 69 females) were evaluated for vec, second-degree atrioventricular block, and supraventricular escape complexes. Mean heart rate was highest at times of maximal human contact (eg, feeding, cleaning) and lowest at periods of no human contact. Bradycardia was observed in 27 of 44 males (61.4%) and 18 of 46 females (39.1%). Sinus pause was identified in 33 of 44 males (75%) and 30 of 46 females (65.2%). Frequency of bradycardia and sinus pause tended to vary inversely with mean heart rate. Ventricular ectopic complexes were detected in 18.8 to 26.1% of the ecg analyzed by use of either method. Although vec runs and bigeminy were observed, most vec were single and occurred sporadically. Second-degree atrioventricular block was observed in 6 of 69 males (8.7%) and 14 of 69 females (20.3%); episodes often were single and occurred sporadically. Supraventricular escape complex occurred in 2 of 69 females (2.9%). Multiple types of abnormal complexes were observed in 2 of 69 males (2.9%) and 6 of 69 females (8.7%). Among clinically normal Beagles, ambulatory electrocardiography detects a higher percentage of dogs with vec, second-degree atrioventricular block, and supraventricular ectopic complexes than does resting electrocardiography.
Simultaneous identification and determination of residual penicillins by use of high-performance liquid chromatography with spectrophotometric or fluorometric detectors
Authors: Hong Chih-Chun , Lin Chin-Lan , Tsai Chin-En , Kondo Fusao
Published: January 2024

Using 7 penicillins (amoxicillin, ampicillin, methicillin, penicillin G, oxacillin, cloxadllin, and dicloxadllin), simultaneous and direct determination of residual penicillins in biological samples was carried out by use of bioassay and high-performance liquid chromatography with spectrophotometric or fluorometric detectors.

By use of assay medium seeded with penicillin-sensitive Micrococcus luteus (ATCC No. 9341) as a test organism, we were able to detect penicillins even at low concentrations. All penicillins treated with 10 U of penicillinase/ml did not produce inhibition zones by disk testing even at a concentration of 100 μg of penicillin/ml/assay plate.

Using a mobile phase of acetonitrile:methanol: 0.01M KH2PO4 (19:11:70, v/v/v; pH, 7.1), standard solutions of the penicillins were separated from each other by use of high-performance liquid chromatography analysis, producing symmetric peaks without tailing each of which had a characteristic retention time. Simultaneous detection of residual penicillins in bovine serum, kidneys, and liver, for the 5 penicillins for which analysis was possible by use of the uv method, yielded recovery rates from 71.4 to 102.3%; for the 2 amino-penicillins, amoxicillin and ampicillin, which could only be detected by use of the fluorometric method, recovery rate ranged from 72.9 to 103%.
Enantioselective glucuronidation and subsequent biliary excretion of carprofen in horses
Authors: Soraci Alejandro , Benoit Etienne , Jaussaud Philippe , Lees Peter , Delatour Paul
Published: January 2024

Carprofen (cpf) enantiomers and their glucuronide conjugates (gluc) were measured in plasma and bile of horses after iv administration of the racemic compound (0.7 mg/kg of body weight). The cpf was detectable in plasma for up to 72 hours after dosing, whereas gluc appeared early (time for maximal plasma concentration, 1 hour) and was measurable transiently at low concentration (maximal plasma concentration, 0.5 μg/ml). The enantiospecific plasma profiles indicated a clear predominance of R-cpf, whereas the stereoselectivity of the glucuronides favored S-gluc. At 1, 2, and 12 hours after administration of the drug, bile concentrations of gluc were high compared with those in plasma and enantioselectivity favored S-gluc. These data indicate that the higher body clearance observed for S-cpf is a consequence of the enantioselectivity in liver glucuronidation and subsequent biliary excretion of the S enantiomer of the drug.
Specific antibodies in serum and vaginal mucus of heifers inoculated with a vaccine containing Tritrichomonas foetus
Authors: Gault Ruth A. , Kvasnicka William G. , Hanks Donald , Hanks Maynard , Hall Mark R.
Published: January 2024

Thirty-five heifers were allotted to 3 groups. Group 1 (control) consisted of 10 heifers that were not vaccinated and were challenge exposed by breeding to infected bulls. Group 2 (natural challenge exposure) consisted of 10 heifers that were vaccinated and challenge exposed by breeding to infected bulls. Group 3 (experimental challenge exposure) consisted of 15 heifers that were vaccinated and challenge exposed by breeding to infected bulls and by intravaginal inoculation with 107 Tritrichomonas foetus. Total immunoglobulin concentrations and specific trichomonal antibodies were determined in serum and vaginal secretions of heifers, using radial immunodiffusion and elisa procedures.

Control heifers remained infected for a mean of 10.6 weeks (range, 0 to 18 weeks), and heifers of the natural and experimental challenge-exposure groups remained infected for 3.2 and 5.0 weeks, respectively (range, 0 to 12 weeks). Total serum and cervicova- ginal mucus concentrations of IgM, IgA, IgG1, and IgG2 did not change significantly after vaccination or challenge exposure. However, elisa titers of total trichomonal antibodies increased up to 1:10,000 (range, 1:400 to 1:10,000) in serum after vaccination, and increased approximately tenfold above background in cervicovaginal mucus. In serum, the predominant trichomonal antibody isotype was IgG1, although trichomonal IgA and IgM antibodies also increased. The predominant trichomonal antibody detected in cervicovaginal mucus was IgA. Antibody titers in serum and cervicovaginal mucus of vaccinated heifers were not increased by infection. However, in control heifers, the total local trichomonal antibody response increased three- to fivefold after infection. In these heifers, specific antibodies in serum were predominantly IgGI and local (cervicovaginal) antibodies were predominantly IgA.
Influence of allopurinol and two diets on 24-hour urinary excretions of uric acid, xanthine, and ammonia by healthy dogs
Authors: Bartges Joseph W. , Osborne Carl A. , Felice Lawrence J. , Unger Lisa K. , Chen Menglan
Published: January 2024

Hyperxanthinuria and xanthine uroliths have been recognized with increased frequency in dogs with ammonium urate uroliths that had been given allopurinol. We hypothesized that dietary modification might reduce the magnitude of uric acid and xanthine excretion in urine of dogs given allopurinol. To test this hypothesis, excretion of metabolites, volume, and pH were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of allopurinol administration (15 mg/kg of body weight, PO, q 12 h) and consumption of 2 special purpose diets: a 10.4% protein (dry matter), casein-based diet and a 31.4% protein (dry matter), meat-based diet.

Significantly lower values of uric acid (P = 0.004), xanthine (P = 0.003), ammonia (P = 0.0002), net acid (P = 0.0001), titratable acid (P = 0.0002), and creatinine (P = 0.01) excreted during a 24-hour period were detected when dogs consumed the casein-based diet and were given allopurinol, compared with the 24-hour period when the same dogs consumed the meat-based diet and were given allopurinol. For the same 24-hour period, urine pH values, urine volumes, and urine bicarbonate values were significantly (P = 0.0004, P = 0.04, and P = 0.002, respectively) higher during the period when the dogs were fed the casein-based diet and given allopurinol than when they were fed the meat-based diet and given allopurinol. Endogenous creatinine clearance was significantly (P = 0.006) lower when dogs were fed the casein-based diet and given allopurinol than when they were fed the meat-based diet and given allopurinol. Significantly lower concentrations of plasma uric acid (P = 0.0001), plasma xanthine (P = 0.01), and serum urea nitrogen (P = 0.0001) were detected when dogs consumed the casein-based diet and were given allopurinol than when they consumed the meat-based diet and were given allopurinol. On the basis of these results, use of the casein-based diet and allopurinol in protocols designed for dissolution of urate uroliths may be beneficial in preventing hyperxanthinuria and xanthine urolith formation.
Clinical pharmacologic aspects of cefixime in dogs
Authors: Lavy E. , Ziv G. , Aroch I. , Glickman A.
Published: January 2024

The minimal inhibitory concentration (mic) of cefixime, a new third-generation orally administered caphalosporin, was determined for reference and clinical isolates from dogs. The mic of the drug for all but 1 of the 18 Enterobacteriaceae isolates tested, 1 Pasteurella canis, 1 Rhodococcus equi, 1 Streptococcus canis, and 1 Streptococcus group G isolate, was less than 1.0 μg/ml. The mic for 9 Staphylococcus intermedius isolates ranged from 1.56 to 6.25 μg/ml and, for 8 Sta aureus isolates, the mic values ranged from 1.56 to 12.5 μg/ml. Pseudomonas aeruginosa, Actinomyces sp, and a single Bordetella bronchiseptica isolate were considered resistant to cefixime.

Cefixime was administered orally in 2 phases at a standard dosage of 5 mg/kg of body weight to clinically normal adult male and female dogs. In the first phase, the drug was given once as a capsule and once as a suspension. In the second phase, it was administered once per day for 6 consecutive days in capsule form. Serum drug concentration was determined by use of a microbiological assay, and the following kinetic values were estimated for each dog: area under the concentration-time curve, peak serum drug concentration (Cmax), time of Cmax, absorption half-life, and elimination half-life (t1/2el) The kinetic profile of the drug in serum after oral administration of a single dose of cefixime was similar, with mean Cmax values of 3.36 and 4.76 μg/ml after treatment with the capsule and suspension, respectively. Quick oral absorption is characteristic for cefixime in dogs; mean absorption half-life values of 1.3 and 0.58 hours for the capsule and suspension, respectively, were calculated. Drug elimination from serum was biphasic, with an initial mean t1/2el of 8.1 to 8.6 hours and a secondary mean t1/2el of 11.7 to 14.5 hours. In the trial involving once daily treatment for 6 days, serum drug concentration after the sixth dose was significantly (P < 0.05) higher than that after the first dose, indicating drug accumulation. Cefixime is extensively bound to canine serum proteins (82 to 92% at concentration ranging between 7.5 and 1.5 μg/ml). Concentration of cefixime was determined in the uterus, ovaries, and abdominal fat tissues 24 hours after single-dose treatment and 24 hours after the sixth treatment. Tissue drug distribution was limited after administration of the single dose, but improved after the sixth dose. The in vitro antibacterial activity of the drug and its pharmacokinetic properties warrant assessing its clinical and bacteriologic efficacy as a longterm once-daily orally administered treatment for common bacterial infections in dogs.
Assessment of protection from systemic infection or disease afforded by low to intermediate titers of passively acquired neutralizing antibody against bovine viral diarrhea virus in calves
Authors: Bolin Steven R. , Ridpath Julia F.
Published: January 2024

Colostrum-deprived calves (n = 24) were fed various amounts of colostrum, colostrum substitute, or milk replacer to establish a range in titer of passively acquired viral neutralizing antibody in serum. The calves were then challenge exposed intranasally with a virulent, noncytopathic bovine viral diarrhea virus (bvdv-890). After viral challenge exposure, calves were monitored for fever, leukopenia, thrombocytopenia, and diarrhea. In addition, viral isolation and viral titration were performed on specimens of nasal secretions, buffy coat cells, and serum obtained from the calves. Fever and systemic spread of virus were detected in calves that had viral neutralizing titer of 256 or lower. Calves that had viral neutralizing titer lower than 16 developed severe clinical disease manifested by fever, leukopenia, thrombocytopenia, and diarrhea. Severity and duration of signs of disease decreased as titers of passively acquired viral neutralizing antibody increased. These results indicate that low to intermediate titers of passively acquired viral neutralizing antibody were not sufficient to fully protect calves from virulent bovine viral diarrhea virus.
Bovine immunodeficiency virus in stud bull semen
Authors: Nash Jerry W. , Hanson Larry A. , Cyr Coats Karen St.
Published: January 2024

Bovine immunodeficiency virus (biv), a lentivi- rus, is prevalent in dairy and beef cattle in southeastern United States and may be associated with a lymphoproliferative disease. The mode(s) of biv transmission are undefined. Because artificial insemination is a common practice in dairy production, contaminated stud semen could serve as an important source of infection if the virus is harbored in seminal fluids. To evaluate this possibility, we procured 11 cryopreserved semen specimens from a stud semen repository. Leukocytes were purified from the specimens, and the leukocyte dna was used as template in a polymerase chain reaction procedure that targeted a 235-base pair, highly conserved domain of the biv pol gene. The target sequence was amplified from the seminal leukocyte dna of 9 of the specimens (82%), and nucleotide sequencing confirmed the biv specificity of the fragment. This finding provides evidence that stud bull semen may serve as an important reservoir of biv, suggesting the possibility that artificial insemination of dairy cows may have a major role in transmission and wide-spread dissemination of this bovine lentivirus.