bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survival analysis of risk factors associated with the occurrence of lameness in a Michigan horse population
Authors: Ross Whitney A. , Kaneene John B. , Gardiner Joseph C. 
Published: January 2024

SUMMARY

Objective
To evaluate the associations of operation and individual animal-level risk factors with occurrence of lameness in the Michigan horse population.

Sample Population
3,925 horses monitored from 138 randomly selected Michigan operations for a total of 814,753 horse-days.

Procedure
All horses monitored < 60 days were eliminated from the source population. From the remaining horses, a prospective unmatched case-control study population was generated that included all cases and a random sample of noncases. Analysis of risk factors associated with occurrence of lameness was conducted, using Cox's proportional hazards regression model.

Results
Horses in larger operations, compared with horses in the first operation size quartile, were associated with decreased risk of lameness (2nd quartile [Qj: hazard ratio [HR] = 0.57; 95% confidence interval [CI]: 0.36, 0.91; 3rd Q: HR = 0.74; 95% CI: 0.49, 1.13; 4th Q: HR = 0.46; 95% CI: 0.28, 0.76). Compared with mares, stallions (HR = 1.90; 95% CI: 1.17, 3.07) and geldings (HR = 1.46; 95% CI: 1.02, 2.09) were at increased risk of lameness. Compared with horses used for breeding purposes only, those participating in exercise or performance-related activities including racing (HR = 4.70; 95% CI: 1.70, 13.03) and showing (HR = 2.80; 95% CI: 1.07, 7.28) also were at increased risk of lameness.

Conclusions
Comparison of these results with those conducted using multivariable logistic regression strengthens the argument that there is decreased risk of lameness for horses in larger operations and increased risk of lameness for active horses. Additionally, results of this analysis suggested that stallions and geldings are at increased risk of lameness, compared with mares.

Clinical Relevance
Lameness prevention strategies in the horse industry should focus principally on horses participating in exercise or performance-related activities, including racing and showing, on male horses, and on horses stabled in smaller operations. (Am J Vet Res 1998;59:23–29)
Molecular cloning and cartilage gene expression of equine stromelysin 1 (matrix metalloproteinase 3)
Authors: Balkman Cheryl E. , Nixon Alan J. 
Published: January 2024

SUMMARY

Objective
To clone and determine molecular structure of equine stromelysin 1 (matrix metalloproteinase 3) and examine stromelysin expression in articular cartilage.

Samples and Procedure
Total RNA was harvested from equine arthritic cartilage specimens and was used for reverse transcription and polymerase chain reaction amplification to develop overlapping complementary DNA (cDNA) clones. Four cDNA sequences were ligated into plasmid (pGEM3Z) constructs and subcloned into bacterial expression vectors, and sequence was determined by automated dye terminator sequencing. Stromelysin mRNA expression was assessed in normal and arthritic cartilage and synovium by northern blotting. Interleukin 1 (IL-1) regulation of stromelysin transcriptional activity in articular chondrocytes cultured in the presence of 0, 20, and 50 ng of IL-1α/ml was assessed by northern blotting of total RNA isolated from the cell layer and probed with 32P-labeled stromelysin cDNA.

Results
4 overlapping clones provided the full-length cDNA sequence of equine stromelysin, including portions of untranslated 5′ and 3′ regions, and the entire translated portion coding for the stromelysin prepropeptide. The coding region of 1,431 base pairs was well conserved between species, with 86, 83, and 78% sequence homology to that of human, rabbit, and mouse stromelysin, respectively. Predicted amino-acid (AA) sequence data indicated highly conserved features. Comparison of the equine AA sequence revealed 89, 88, and 84% homology to the AA structure in human, rabbit, and mouse stromelysin, respectively. Minimal stromelysin mRNA expression was evident in normal cartilage and synovium, and increased expression was evident in arthritic cartilage. Marked dose-dependent up-regulation of stromelysin transcriptional activity was evident in chondrocyte cultures exposed to 20 and 50 ng of IL-1/ml.

Conclusions
Stromelysin DNA sequence in horses is similar to that in people and rodents. Constitutive stromelysin message amounts in normal cartilage and synovium are low, but considerably increased in arthritic cartilage and in chondrocytes exposed to IL-1. (Am J Vet Res 1998;59:30–36)
Expression of adhesion molecules on neutrophils of periparturient cows and neonatal calves
Authors: Lee Eun-kyung , Kehrli Marcus E. 
Published: January 2024

SUMMARY

Objective
To determine expression of the β2-integrin (CD18) family of adhesion molecules and L-selectin (CD62L) on neutrophils from periparturient cows and calves.

Animals
8 periparturient Holstein cows and 9 Holstein calves.

Procedure
Constitutive CD18 and CD62L expression on neutrophils was determined by flow cytometry, using specific monoclonal antibodies. Platelet-activating factor was used to activate neutrophils in vitro to measure down-regulation of CD62L and up-regulation of CD18 on activated neutrophils.

Results
Mean values for constitutive and platelet-activating factor-stimulated CD18 expression on neutrophils from cows and calves were highest at parturition, then decreased during the first 24 hours after parturition on calf neutrophils, whereas CD62L expression decreased markedly by 9 to 24 hours after parturition on cow and calf neutrophils. Constitutive amounts of CD18 and CD62L on cow neutrophils returned to prepartum values by day 3 after parturition. Amounts of CD18 expression on calves’ neutrophils recovered by 1 week of age, but did not reach original birth values, whereas CD62L expression exceeded birth values by day 3 after parturition. Cows had leukocytosis (neutrophilia), with a doubling of circulating neutrophils 9 hours after calving that was inversely correlated with CD62L expression on neutrophils.

Conclusions and Clinical Relevance
Low amounts of CD62L and CD18 on calf neutrophils and of CD62L on neutrophils from cows for several days after parturition may result in impaired inflammatory response. Low CD62L expression may contribute to increased susceptibility to disease. (Am J Vet Res 1998;59:37–43)
Disposition of cyproheptadine in cats after intravenous or oral administration of a single dose
Authors: Norris Carol R. , Boothe Dawn M. , Esparza Teri , Gray Connie , Ragsdale Michelle 
Published: January 2024

SUMMARY

Objective
To determine disposition of cyproheptadine hydrochloride in cats after intravenous or oral administration of a single dose.

Animals
6 healthy cats.

Procedure
A randomized crossover design was used, and each cat was studied after intravenous (2 mg) and oral (8 mg) administration of cyproheptadine. Blood samples were collected at fixed time intervals after drug administration, and serum cyproheptadine concentration was determined by means of polarized immunofluorescence.

Results
Mean (± SD) residence time was significantly longer after oral (823 ± 191 minutes) than after intravenous (339 ±217 minutes) administration, but no significant differences were detected between other pharmacokinetic parameters after oral and intravenous administration. Mean ± SD oral bioavailability was 1.01 ± 0.36. Mean elimination half-life after oral administration was 12.8 ± 9.9 hours. Peak extrapolated cyproheptadine concentration was 669 ± 206 ng/ml. Only 1 cat developed adverse effects (transient vocalization).

Conclusions
Cyproheptadine appeared to be well tolerated in cats and had high bioavailability after oral administration. The mean elimination half-life of 12 hours indicated that approximately 2.5 days must elapse to achieve steady-state concentrations of cyproheptadine after oral administration of multiple doses. A 12-hour dosing interval is acceptable, but an 8-hour interval may be indicated for some cats.

Clinical Relevance
On the basis of pharmacokinetic parameters determined in this study, the oral form of cyproheptadine appears to be suitable for use in clinical trials to treat anorexia in cats. Its half-life is compatible with once or twice daily dosing. (Am J Vet Res 1998;59:79–81)
Safety, immunogenicity, and efficacy of an inactivated avian polyomavirus vaccine
Authors: Ritchie Branson W. , Latimer Kenneth S. , Leonard Joan , Pesti Denise , Campagnoli Raymond , Lukert Phil D. 
Published: January 2024

SUMMARY

Objective
To determine safety, immunogenicity, and efficacy of an inactivated avian polyomavirus vaccine in nonbudgerigar psittacine birds that varied in age, species, and immunologic status.

Animals
Safety of the vaccine was evaluated in 1,823 psittacines representing more than 80 species. Immunogenicity was evaluated in 285 birds (260 of various Psittaciformes species, 25 chickens). Efficacy was evaluated in 104 birds (78 of various Psittaciformes species, 26 chickens).

Procedures
Safety was evaluated by vaccinating birds that were determined to be seronegative or seropositive (titer > 1:10) prior to vaccination. Birds were then evaluated for clinically detectable systemic or local reactions for 2 months to 2 years. Immunogenicity was evaluated by testing for virus-neutralizing antibodies, vaccinating each bird twice, and then testing for a significant change in antibody titer. Efficacy was evaluated by vaccinating birds, followed in 2 to 4 weeks by intramuscular or intravenous challenge exposure. After challenge exposure, protection was evaluated by attempting to recover virus from tissues or by observing birds for clinical signs of disease and testing for a significant change in titer.

Conclusions
Avian polyomavirus vaccine is safe, immunogenic, and efficacious for use in multiple species of mature and immature psittacines.

Clinical Relevance
Until now, prevention of polyomavirus infection in psittacine birds could only be accomplished through strict isolation to reduce potential exposure to the virus. The USDA-registered inactivated avian polyomavirus vaccine can safely be used to protect vaccinates from infection and control spread of this virus in flocks. (Am J Vet Res 1998,59:143–148)
Effect of endotoxin on hormonal responses to thyrotropin and thyrotropin-releasing hormone in dogs
Authors: Yu Anthony A. , Kemppainen Robert J. , MacDonald John M. 
Published: January 2024

SUMMARY

Objective
To determine whether administration of endotoxin affects thyroid gland function in dogs.

Animals
24 Beagles.

Procedure
Dogs were given thyrotropin (TSH) or thyrotropin-releasing hormone (TRH) on 2 occasions. Twenty-four hours before the second challenge with TSH or TRH, all dogs were given 5 μg of endotoxin/kg of body weight. Serum concentrations of thyroxine (T4), free T4 (fT4), 3,3′,5-triiodothyronine (T3), reverse T3, autoantibodies to T3, and plasma concentrations of ACTH and cortisol were determined.

Results
Treatment with endotoxin was associated with reduced baseline concentration of serum T3 and increased baseline concentration of reverse T3 and free T4. Endotoxin treatment resulted in reduced peak serum concentration of T4 after TSH and TRH. However, peak serum concentration of fT4 after TSH and TRH were not affected by endotoxin.

Conclusions
A single dose of endotoxin affects several aspects of thyroid gland function in dogs, including T4 binding, deiodinase activity, and the thyroidal response to TSH and TRH.

Clinical Relevance
Acute or chronic nonthyroidal illness may affect thyroid gland function in dogs. Determination of fT4 concentration may provide a means of differentiating the effects of nonthyroidal illness from those of thyroid dysfunction, because endotoxin treatment was associated with increased baseline serum free T4 concentration and unchanged peak serum fT4 concentration after administration of TSH or TRH. (Am J Vet Res 1998;59:186–191)
Effect of five percent dehydration on breath hydrogen concentrations in dogs
Authors: Bissett S. A. , Guilford W. G. , Haslett S. J. , Sunvold G. D. 
Published: January 2024

Abstract

Objective
To determine the effect of mild dehydration (5%) on expired breath H2 concentrations in dogs.

Animals
10 healthy, colony-source dogs.

Procedure
Expired breath samples were collected at baseline, and every 90 minutes for 18 hours after ingestion of a test meal (commercial dog food and kibbled wheat) in fully hydrated dogs and in the same dogs when they had lost 5% of their body weight after food and water deprivation. The areas under the breath H2 concentration versus time curves (AUC) for the dehydrated and nondehydrated states were compared, using a two-stage, balanced, crossover, repeated measures technique. The number of breath samples considered to be contaminated by flatus were compared by use of a one-sided sign test.

Results
Expired breath H2 concentration of dogs during the dehydration test period was significantly (P < 0.02) greater than that during the nondehydration test period. In addition, flatulence was significantly (P < 0.033) more frequent in dogs during the dehydration period.

Conclusions
Dehydrated dogs have greater expired breath H2 concentration and produce more flatus after ingestion of a carbohydrate-containing meal. Considered together, these findings suggest that dehydration results in an increase in the net amount of H2 produced in the gastrointestinal tract.

Clinical Relevance
Care should be taken to assess the hydration status, and to correct hydration deficits of dogs prior to breath H2 testing. (Am J Vet Res 1998;59:245–249)
Serum markers of bone metabolism in dogs
Authors: Allen Matthew J. , Hoffmann Walter E. , Richardson Daniel C. , Breur Gert J. 
Published: January 2024

Abstract

Objective
To establish reference values for a panel of serum markers of bone turnover in dogs of various ages.

Animals
Dogs in 4 age groups (0 to 1 year; 1 to 2 years; 3 to 7 years; > 8 years).

Procedure
Serum concentrations of the carboxyterminal propeptide of type-I procollagen (PICP) and the aminoterminal propeptide of type-I procollagen (PINP), both markers of type-I collagen synthesis (hence, bone formation), were measured by use of commercial human radioimmunoassay kits. Serum concentrations of the carboxyterminal cross-linked telopeptide of type-I collagen (ICTP), a marker for type-I collagen breakdown (hence, bone resorption), also were measured by use of a commercial human radioimmunoassay kit. Serum osteocalcin (OC) concentrations and alkaline phosphatase (ALP) isoenzyme activities were measured by use of techniques developed specifically for dogs.

Results
As expected, the highest values for all of the markers were found in young dogs (< 12 months old). Concentrations of OC and ICTP decreased with age, and were lowest in dogs > 8 years old. Total ALP and bone-specific ALP activities initially decreased with age, then increased in dogs > 8 years old.

Conclusions and Clinical Relevance
Serum markers of bone turnover may be useful diagnostic and prognostic tools for management of dogs with musculoskeletal disorders. (Am J Vet Res 1998;59:250–254)
Pharmacokinetics of ketoprofen in healthy foals less than twenty-four hours old
Authors: Wilcke Jeff R. , Crisman Mark V. , Scarratt W. Kent , Sams Richard A. 
Published: January 2024

Abstract

Objective
To determine pharmacokinetic variables that describe disposition of ketoprofen after its IV administration to foals < 24 hours old.

Animals
6 healthy foals (1 male and 5 females); mean age, 12.5 (range, 8.5 to 17) hours at time of dose administration.

Procedure
Ketoprofen was administered IV to foals at a dosage of 2.2 mg/kg of body weight. Ketoprofen concentration in plasma samples was analyzed, using high-performance liquid chromatography. Concentration versus time profiles were analyzed according to standard pharmacokinetic techniques. Blood samples were obtained from foals by jugular venipuncture at defined times during a 48-hour period. Samples were centrifuged, and plasma was frozen at −70 C until analyzed. One-, two-, and three-compartment analyses were conducted. The most appropriate model was determined by use of Akaike's information criterion analysis.

Results
Plasma concentration versus time profiles were best described, using a two-compartment open model. Clearance (normalized for body weight) was significantly lower than that determined for adult horses. Volume of distribution (normalized for body weight) was larger than that determined for adult horses. Mean (harmonic) plasma half-life for healthy foals < 24 hours old was 4.3 hours.

Clinical Relevance
Although additional factors, such as dehydration or sepsis, must be considered on a case-by-case basis, the dose of ketoprofen administered to foals < 24 hours old should be different from the dose administered to adult horses. Under similar clinical circumstances, doses in foals should be increased by as much as 1.5 times to produce comparable therapeutic concentrations; longer dose intervals, based on clinical response, would be necessary to avoid drug toxicity. (Am J Vet Res 1998;59:290–292)
Evaluation of serologic responses, lymphocyte proliferative responses, and clearance from lymphatic organs after vaccination of bison with Brucella abortus strain RB51
Authors: Olsen Steven C. , Jensen Allen E. , Palmer Mitchell V. , Stevens Mark G. 
Published: January 2024

Abstract

Objective
To evaluate clearance of the vaccine strain, immunologic responses, and potential shedding of Brucella abortus strain RB51 organisms after vaccination of bison calves.

Animals
Fourteen 7-month-old female bison calves.

Procedure
10 bison calves were vaccinated SC with 1.22 × 1010 colony-forming units of B abortus strain RB51. Four bison calves were vaccinated SC with 0.15M NaCl solution. Rectal, vaginal, nasal, and ocular swab specimens were obtained to evaluate potential shedding by vaccinated bison. The superficial cervical lymph node was biopsied to evaluate clearance of the vaccine strain. Lymphocyte proliferative responses to strain RB51 bacteria were evaluated in lymph node cells obtained from biopsy specimens and also in peripheral blood mononuclear cells.

Results
Strain RB51 was recovered from superficial cervical lymph nodes of vaccinates examined 6, 12, and 18 weeks after vaccination (4/4, 3/4, and 1/4, respectively) but not in vaccinates examined at 24 weeks (0/3) after vaccination or nonvaccinates examined at all sample collection times (n = 1 bison/sample period). Serologic, immunologic, and bacterial culture techniques failed to reveal shedding of strain RB51 by vaccinates or infection of nonvaccinated bison. Lymphocyte proliferative responses were evident in lymph node cells and blood mononuclear cells from strain RB51-vaccinated bison beginning 12 weeks after vaccination.

Conclusion
Strain RB51 was cleared from bison by 18 to 24 weeks after vaccination. Bison vaccinated with strain RB51 did not shed the vaccine strain to nonvaccinated bison housed in close proximity. Strain RB51 did not induce antibody responses in bison that would interfere with brucellosis surveillance tests, but did stimulate cell-mediated immunity. (Am J Vet Res 1998;59:410–415)
Cloning of equine interleukin 1α and equine interleukin 1ß and determination of their full-length cDNA sequences
Authors: Howard Rick D. , McIlwraith C. Wayne , Trotter Gayle W. , Nyborg Jennifer K. 
Published: January 2024

Abstract

Objectives
To clone equine interleukin 1α (IL-1α) and equine interleukin 1β (IL-1β) and determine their full-length cDNA sequences.

Procedure
The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a λ phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1α and IL-1ß cDNA probes. The cDNA nucleotide sequences for equine IL-1α and equine IL-1β were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using computer software, for sequence characteristics and compared with sequences reported for other species.

Results
The cDNA for equine IL-1α was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equine IL-1β was 1,473 base pairs in length with an ORF encoding a peptide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL- 1α and sequences for IL-1 α of other species ranged from 62.5 to 82.2%; similarity between amino acid sequence of equine IL-1ß and sequences for IL-1β of other species ranged from 62.5 to 66.4%. Similarity between amino acid sequences of equine IL-1α and equine IL-1β was 26%.

Conclusions and Clinical Relevance
Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:704-711)
Comparison of anion gap and strong ion gap as predictors of unmeasured strong ion concentration in plasma and serum from horses
Authors: Constable P. D. , Hinchcliff K. W. , Muir W. W. 
Published: January 2024

SUMMARY

Objective
To compare the accuracy of anion gap (AG) and strong ion gap (SIG) for predicting unmeasured strong ion concentration in plasma and serum from horses.

Animals
6 well-trained Standardbred horses undergoing high-intensity exercise (experimental study) and 78 horses and ponies that underwent IV administration of lactic acid or endotoxin, and endurance, submaximal, or high-intensity exercise.

Procedure
Anion gap was calculated as AG = (Na+ + K+) − (Cl- + HCO−3), and SIG was calculated, using the simplified strong ion model, whereby SIG (mEq/L) = 2.24 × total protein (g/dl)/(1 + 106.65−pH) − AG. The relation between AG or SIG and plasma lactate concentration was evaluated, using linear regression analysis.

Results
Linear relations between plasma lactate concentration and AG and SIG were strong for the experimental study (r2 = 0.960 and 0.966, respectively) and the published studies (r2 = 0.914 and 0.925, respectively). The following relations were derived: AG = 1.00 × plasma lactate + 10.5; SIG = 0.99 × plasma lactate + 2.8. An AG > 15 mEq/L indicated an increased unmeasured anion concentration, whereas a SIG < −2 mEq/L indicated an increased unmeasured strong anion concentration.

Conclusions and Clinical Relevence
Anion gap and SIG can be used to predict plasma lactate concentration in horses. AG is accurate and clinically useful for estimating unmeasured strong ion concentration in horses with total protein concentrations within or slightly outside reference range, whereas SIG is more accurate in horses with markedly abnormal total protein concentrations and those of various ages and with various concentrations of albumin, globulin, and phosphate. (Am J Vet Res 1998;59:881–887)