bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Summary
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

Summary
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

Summary
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

SUMMARY
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

SUMMARY
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

SUMMARY
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

SUMMARY
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

SUMMARY
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

SUMMARY
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

SUMMARY
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

SUMMARY
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.