bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacokinetics of cefepime and comparison with those of ceftiofur in horses
Authors: Guglick Mary Ann , MacAllister Charles G. , Clarke Cyril R. , Pollet Robert , Hague Christinia , Clarke Jean Μ. 
Published: January 2024

Abstract

Objective
To determine pharmacokinetics of IV, IM, and oral administration of cefepime in horses and to compare pharmacokinetics of IM administration of cefepime with those of ceftiofur sodium.

Animals
6 clinically normal adult horses.

Procedure
Horses received 3 doses of cefepime (11 mg/kg of body weight, PO; 2.2 mg/kg, IV; and 2.2 mg/kg, IM) and 1 dose of ceftiofur (2.2 mg/kg, IM). Two horses also received l-arginine, PO and IV, at doses identical to those contained in the cefepime dihydrochloride-l-arginine preparations previously administered. Blood samples were collected for 24 hours after administration of cefepime or ceftiofur and were assayed for cefepime and ceftiofur concentrations.

Results
Pharmacokinetic analysis of disposition data indicated that IV administration data were best described by a 2-compartment open model, whereas IM administration data were best described by a 1-compartment absorption model. Median elimination half-life and volume of distribution after IV administration of cefepime were 125.7 minutes and 225 ml/kg, respectively. After IM administration of cefepime, mean maximal plasma concentration of (8.13 μg/ml) was reached at a mean time of 80 minutes. Absorption of cefepime after IM administration was complete, with a median bioavailability of 1.11. Intramuscular administration of ceftiofur resulted in similar mean maximal plasma concentration (7.98 μg/ml) and mean time to this concentration (82 minutes). Cefepime was not detected in samples collected after oral administration. Adverse effects consisting principally of gastrointestinal disturbances were observed after oral and IM administration of cefepime and after 1 IM administration of ceftiofur.

Conclusions and Clinical Relevance
Cefepime, administered IV or IM at a dosage of 2.2 mg/kg, every 8 hours is likely to provide effective antibacterial therapy for cefepime-sensitive organisms in horses. Further studies are needed to evaluate adverse effects on the gastrointestinal tract. (Am J Vet Res 1998;59:458–463)
Changes in plasma atrial natriuretic peptide concentration in exercising horses in relation to hydration status and exercise intensity
Authors: Nyman Sara , Kokkonen Ulla-Maija , Dahlborn Kristina 
Published: January 2024

Abstract

Objective
To investigate effects of hydration status and exercise intensity on plasma atrial natriuretic peptide (ANP) concentration in exercising horses.

Animals
4 trained Standardbreds.

Procedure
Horses performed a 40-minute exercise test at 65 to 70% maximal heart rate (HRmax; no incline) and a 12-minute test at approximately 90% HRmax (3.5° incline). The 40-minute test was performed with ad libitum access to drinking water (normohydration), after water had been withheld for 24 hours (dehydration), and 30 minutes after 12 L of water at body temperature had been given via nasogastric tube (hyperhydration). The 12-minute test was only performed with normohydrated horses.

Results
Plasma ANP concentration was higher toward the end of exercise during hyperhydration than during the other 2 hydration states, and the area under the plasma ANP concentration curve was significantly greater during hyperhydration than during dehydration. The maximal plasma ANP value induced during the 12-minute test was similar to that of the 40-minute test. After the 12-minute test, plasma ANP concentration did not decrease during the first 30 minutes of recovery, whereas after the 40-minute test, plasma ANP concentration decreased by approximately 30% during the same period.

Conclusions
Hydration status can affect plasma ANP concentration in horses during submaximal exercise. Maximal plasma ANP concentration was similar at the 2 exercise intensities studied, but the postexercise return to baseline values differed.

Clinical Relevance
Changes in hydration status can cause alterations in plasma concentration of ANP, one of the hormones involved in the control of cardiovascular functions during exercise. (Am J Vet Res 1998;59:489–494)
Evaluation of antemortem polymerase chain reaction and serologic methods for detection of Lawsonia intracellularis-exposed pigs
Authors: Knittel Jeffrey P. , Jordan Dianna Μ. , Schwartz Kent J. , Janke Bruce H. , Roof Michael B. , McOrist Steven , Harris D. L. 
Published: January 2024

Abstract

Objective
To evaluate polymerase chain reaction (PCR) for detection of Lawsonia intracellularis DNA in feces and an indirect fluorescent antibody test (IFAT) for detecting serum IgG antibodies in pigs exposed to L intracellularis.

Animals
15 seven-week-old pigs and 42 three-week-old pigs.

Procedure
During 3 experiments, 23 pigs were inoculated with a pure culture of L intracellularis, 31 pigs served as noninoculated controls, and 3 pigs were used as sentinels. Fecal shedding of L intracellularis was monitored by use of PCR analysis at 7-day intervals. At euthanasia, the ileum was obtained for PCR and histologic analyses. Serum was obtained at 7-day intervals for use in the IFAT.

Results
Polymerase chain reaction analysis detected L intracellularis DNA in the feces of 39% of the inoculated pigs; by postinoculation days 21 to 28, 90% of inoculated pigs developed IgG antibodies detected by IFAT. Neither L intracellularis DNA nor IgG antibodies were detected in any of the noninoculated control pigs at euthanasia. Sera from pigs inoculated with enteric pathogens other than L intracellularis did not contain detectable antibodies that reacted with L intracellularis by use of the IFAT.

Conclusion
The IFAT for L intracellularis IgG antibody detection appeared to be a more sensitive antemortem test for detecting pigs experimentally infected with L intracellularis than was a PCR method for direct detection of the organism in the feces.

Clinical Relevance
Not all animals that are infected with L intracellularis shed the organism in feces at detectable amounts. (Am J Vet Res 1998;59:722-726)
Detection of Staphylococcus aureus in milk by use of polymerase chain reaction analysis
Authors: Khan M. A. , Kim C-H. , Kakoma I. , Morin E. , Hansen R. D. , Hurley W. L. , Tripathy D. N. , Baek B. K. 
Published: January 2024

SUMMARY

Objective
To evaluate polymerase chain reaction (PCR) analysis for detection of Staphylococcus aureus (nuc gene) in fresh and formalin-preserved milk.

Sample Population
Samples from 80 lactating sheep and 100 lactating dairy cows.

Procedure
4 lactating sheep were inoculated with S aureus by intramammary infusion. A set of primers specific for the nuc gene of S aureus was used to develop a PCR technique, and modification of the rapid boil method was used to isolate bacterial DNA. Milk was obtained from experimentally infected sheep before and after infusion with S aureus, and from the 100 cows and remaining 76 sheep. Samples were screened by bacteriologic culture and PCR. To validate the PCR assay, S aureus or other pathogens were added to distilled water and “normal” sheep milk samples, with and without formalin.

Results
The PCR assay was 100% specific for S aureus when known negative and positive samples were tested. Sensitivity was 100% for samples with added S aureus or other pathogens. Sensitivity was lower for samples obtained from experimentally infected sheep, but increased from 53% to 90% with increased washing of target DNA.

Conclusions
The PCR technique based on the nuc gene is able to detect S aureus in sheep milk yields results faster than does traditional culturing, is highly specific, and is able to detect S aureus in formalin-fixed milk samples.

Clinical Relevance
The assay is particularly suitable for analysis of samples shipped or stored without refrigeration. Although antibiotics in milk may inhibit growth in culture, they should not affect the results of the PCR assay. (Am J Vet Res 1998;59:807–813)
Interferon-γ and interleukin 4 gene expression in cows infected with Mycobacterium paratuberculosis
Authors: Sweeney Raymond W. , Jones Douglas E. , Habecker Perry , Scott Phillip 
Published: January 2024

SUMMARY

Objective
To determine whether clinical progression of paratuberculosis in cattle was associated with alterations in cytokine gene expression in affected tissues.

Animals
5 uninfected adult Holstein cows, 7 adult Holstein cows naturally infected with Mycobacterium paratuberculosis that did not have clinical signs of disease, and 4 adult Holstein cows naturally infected with M paratuberculosis that had progressive clinical signs of infection.

Procedure
Samples of ileum and cecal lymph nodes were obtained from each animal at the time of slaughter. A reverse transcriptase-competitive polymerase chain reaction assay was used to determine mRNA expression of interferon-γ (IFN-γ) and interleukin 4 in each sample.

Results
Interferon-γ gene expression was significantly higher in ileum and cecal lymph node samples from subclinically infected cows than from clinically infected cows.

Conclusions and Clinical Relevance
Progression of paratuberculosis to clinical stages is associated with reduced expression of IFN-γ at site of infection. If immune response to M paratuberculosis can be manipulated so that IFN-γ expression is increased, resistance to infection in cattle might be enhanced. (Am J Vet Res 1998;59:842–847)
Effect of intravenous calcium administration on gentamicin-induced nephrotoxicosis in ponies
Authors: Brashier Michael K. , Geor Raymond J. , Ames Trevor R. , O'Leary Terrance P. 
Published: January 2024

Abstract

Objective
To determine whether supplemental IV calcium administration would attenuate or prevent gentamicin-induced acute renal failure, defined as an increase in serum creatinine concentration ≥ 50% above baseline.

Animals
10 healthy pony mares.

Procedure
Pony mares were randomly assigned to receive calcium at a dosage of 20 mg/kg of body weight or saline solution IV, twice daily for 14 days. All pony mares received gentamicin at a dosage of 20 mg/kg IV every 8 hours for 14 days. Gentamicin pharmacokinetic, serum biochemical, and urinalysis data were measured every other day for the 14-day study period. Renal histologic examination was performed, and results were scored at the end of the 14-day period.

Results
4 of 5 mares not receiving calcium supplementation developed acute renal failure. Only 1 of the 5 mares receiving calcium supplementation developed acute renal failure. Over the course of the study, pony mares receiving calcium supplementation had significantly fewer changes in urinalysis variables, and significantly less microscopic renal damage.

Conclusion
Daily IV administration of calcium attenuated gentamicin-induced acute renal failure.

Clinical Relevance
Calcium supplementation may help diminish the risk of acute renal failure associated with aminoglycoside antibiotics. (Am J Vet Res 1998;59:1055–1062)
Detection of milk antibiotic residues by use of screening tests and liquid chromatography after intramammary administration of amoxicillin or penicillin G in cows with clinical mastitis
Authors: Anderson Kevin L. , Moats William A. , Rushing John E. , O'Carroll Julia M. 
Published: January 2024

Abstract

Objective
To compare results of 6 commercially available milk antimicrobial screening tests with results of liquid chromatography (LC) when testing milk samples from individual cows treated for mild clinical mastitis by intramammary (IMM) infusion with amoxicillin or penicillin G.

Animals
6 cows with noninduced clinical mastitis: 3 treated by IMM infusion with amoxicillin and 3 treated by IMM infusion with penicillin G.

Procedure
Composite milk samples were collected before, during, and after treatment. Samples were assayed by use of the screening tests and their results and those of LC were compared. The LC results were assumed to represent the true result.

Results
Results of screening tests compared well with results of LC, with agreement of 94%. Positive screening test results for samples containing drug values below the established tolerance or safe level, as evaluated by LC, were obtained from 2 cows in which abnormal milk, as well as marked increases in composite milk somatic cell count, were observed. With the exception of 1 test in 1 cow, all screening tests had negative results at the end of the labeled milk-withholding time.

Conclusions and Clinical Implications
On the basis of results of the limited sample reported, the screening tests appeared to provide good agreement overall, compared with LC results, when testing milk of individual cows treated by IMM infusion with amoxicillin or penicillin G. Positive screening test results for milk samples containing amoxicillin or penicillin G at values below the established tolerance or safe level, as evaluated by LC, may occasionally be obtained. (Am J Vet Res 1998;59:1096-1100)
Comparison of radiographic and necropsy findings of lung lesions in calves after challenge exposure with Pasteurella multocida
Authors: Jones Gary F. , Feeney Daniel A. , Mews Cindy 
Published: January 2024

Abstract

Objectives
To test suitability of radiographic evaluation of lung lesions as a substitute for lung lesion scores derived by examination at necropsy in challenge-exposure models of bovine pneumonia.

Animals
10 calves selected by body weight from 20 multiple-source male Holstein calves approximately 1 to 2 months old enrolled in a Pasteurella multocida challenge-exposure study.

Procedure
Calves were paired on the basis of weight and randomly assigned within pairs to vaccine or control (saline solution) group. By use of deep tracheal cannulation, calves were challenge exposed with a culture of virulent P multocida, observed for 10 days, euthanatized, and necropsied, and the lungs were scored for pneumonic lesions. Radiographic views of the lung fields of the calves were taken before challenge exposure and before necropsy and were evaluated for alveolar disease by a veterinary radiologist. Lung lesion scores were compared with radiographic evaluations.

Results
There was a strong and significant correlation (R2 = 0.91, P < 0.001) between results of the evaluation of postchallenge-exposure radiographs and necropsy results. There also was also strong and significant correlation (R2 = 0.90, P < 0.001) between evaluation of the prechallenge-exposure radiographs and necropsy results.

Conclusions
Radiographic evaluation of lung lesions correlates well with lung lesions found at necropsy. The findings emphasize the need for caution in interpreting the results of challenge-exposure studies of bovine respiratory tract disease in which small numbers of calves are studied. (Am J Vet Res 1998;59: 1108-1112)
Expression and bioactivity of recombinant canine erythropoietin
Authors: MacLeod James N. , Tetreault Jonathan W. , Lorschy Kellie A. S. , Gu Da Nian 
Published: January 2024

Abstract

Objective
To produce recombinant canine erythropoietin (rcEPO) and compare its biological activity with that of recombinant human EPO (rhEPO).

Animals
C57BL/6J mice.

Procedure
The gene encoding cEPO was isolated from a genomic library and subcloned into an eucaryotic expression vector. Production of rcEPO was achieved by stable transfection of the expression construct into Chinese hamster ovary cells. Biological activity was evaluated in vitro by analyzing the mitogenic activity of rcEPO on murine erythroid progenitor cells. In vivo bioactivity was assessed in mice by measuring the ability of rcEPO to increase blood reticulocyte counts.

Results
Size and glycosylation of rcEPO expressed in Chinese hamster ovary cells were similar to values for commercial rhEPO. Canine and human EPO stimulated proliferation of murine erythroid progenitor cells in vitro and murine reticulocytosis in vivo in a dosedependent manner.

Conclusions
Comparable biological activity was observed for rcEPO and rhEPO in the 2 murine-based assay systems studied. By avoiding interspecies variation in protein structure and the resulting potential for immunogenicity, rcEPO should represent a better option than rhEPO for treatment of dogs with erythropoietin-dependent anemia.

Clinical Relevance
Therapeutic use of rhEPO in companion animals is limited by its immunogenicity and the resulting potential to induce pure red cell aplasia. Development and availability of species-specific EPO preparations should avoid this problem. (Am J Vet Res 1998;59:1144-1148)
Anti-inflammatory effects of topically applied dimethyl sulfoxide gel on endotoxin-induced synovitis in horses
Authors: Smith Gregory , Bertone Alicia L. , Kaeding Christopher , Simmons Emily J. , Apostoles Steven 
Published: January 2024

Abstract

Objective
To evaluate the effect of topically applied dimethylsulfoxide (DMSO) on lipopolysaccharide (LPS)-induced synovitis in the mid-carpal joint.

Animals
6 sound, healthy, adult horses (12 carpi).

Procedure
In a double-blinded, crossover, paired study with a 1-week washout period, mid-carpal joints were allocated to group 1 (DMSO, n = 6) or group 2 (control, n = 6). Each joint was injected with 1.3 ml (0.0125 ng/dl) of LPS to induce synovitis. For group-1 joints, DMSO gel (15 g; 90%) was applied after injection of LPS and at 12-hour intervals for 60 hours. Joints of group 2 received LPS, but not DMSO gel. All horses were evaluated by serial lameness examinations and synovial fluid analyses (total and differential WBC count and total protein concentration) at 12- hour intervals for 60 hours after LPS injection. Plasma and synovial fluid were obtained at baseline and 36 hours to document presence of DMSO.

Results
Mean WBC concentration was significantly (P < 0.05) lower in group-1, compared with group-2 joints, at 24 hours and had a trend to be lower at 36 hours. Mean total neutrophil count was significantly lower in group-1, compared with group-2 joints at 24 hours. In group-1 joints, DMSO was detected by use of gas chromatography in the synovial fluid of 5 of 6 joints and in plasma from 1 of 6 horses.

Conclusion
Topically applied DMSO penetrated into synovial fluid in sufficient quantities to be detected and to decrease joint inflammation. (Am J Vet Res 1998;59:1149-1152)
Detection of Haemobartonella felis in cats with experimentally induced acute and chronic infections, using a polymerase chain reaction assay
Authors: Berent Linda M. , Messick Joanne B. , Cooper Sandra K. 
Published: January 2024

Abstract

Objective
To develop a test for detection of Haemobartonella felis, using a polymerase chain reaction (PCR) assay.

Animals
4 adult cats seronegative for FeLV and feline immunodeficiency virus.

Procedure
Cats were infected with H felis by IV administration of 1 ml of blood obtained from an infected cat. Rectal temperature, PCV, and microscopic examination of blood smears for organisms were monitored daily. At peak of infection, doxycycline treatment was initiated for 21 days. Blood samples were collected at weekly intervals. Six months after treatment, 2 cats were given methylprednisolone (14 mg/kg of body weight, IM). Daily blood samples were collected for CBC, detection of organisms, and PCR evaluation. On the basis of the 16S rRNA gene sequence of H felis,specific PCR primers were created for a 393-basepair internal fragment.

Results
The 393-basepair product was consistently amplified from blood samples obtained during peak parasitemia but not during the last week of or immediately after completion of doxycycline treatment. After treatment, PCV returned to the reference range, and organisms were not observed in blood samples; however, the PCR product could be consistently amplified. After administration of methylprednisolone, organisms were only rarely observed in blood smears but were consistently detected by PCR analysis.

Clinical Relevance
Using PCR analysis, it was possible to detect H felisin blood samples obtained from cats during peak parasitemia, during most of the carrier phase, and after challenge with immunosuppressive drugs. During and immediately after antibiotic treatment, this test may fail to detect the organisms. (Am J Vet Res1998;59:1215–1220)
Effects of acepromazine and butorphanol on positive-contrast upper gastrointestinal tract examination in dogs
Authors: Scrivani Peter V. , Bednarski Richard M. , Myer C. Wendy 
Published: January 2024

Abstract

Objective
To determine whether acepromazine (ACE) and butorphanol (BUT) combination can be used for restraint of dogs during positive-contrast upper gastrointestinal tract (UGIT) examination.

Animals
6 healthy dogs.

Procedure
In a randomized crossover design study, weekly UGIT examinations were performed on each dog for 5 weeks after administration of normal saline solution (0.5 ml), xylazine (1.0 mg/kg of body weight), or a combination of ACE (0.1 mg/kg) and 1 of 3 doses of BUT (0.05, 0.2, 1.0 mg/kg). Gastrointestinal tract emptying time, GI motility, pulse, respiratory rate, and quality of restraint were assessed.

Results
Total gastric emptying time was significantly prolonged by use of an ACE and BUT (0.05 mg/kg) combination. Xylazine and higher dosages of BUT significantly prolonged gastric and intestinal emptying times. All anesthetic protocols significantly decreased motility and facilitated nonmanual restraint. Xylazine and BUT (1.0 mg/kg) significantly decreased pulse and respiratory rate.

Conclusion
The ACE and BUT combination prolonged GI tract emptying times, decreased GI motility, and facilitated nonmanual restraint for duration of the examination. Although GI motility was decreased and total gastric emptying time was prolonged, administration of ACE (0.1 mg/kg) plus BUT (0.05 mg/kg) allowed morphologic examination of the GI tract within 5 hours. Xylazine prolonged GI tract emptying, decreased GI motility, and provided good to excellent initial restraint.

Clinical Relevance
The ACE and BUT combination prohibits functional examination of the GI tract; however, morphologic examination is possible when low dosages of BUT (0.05 mg/kg) are used. (Am J Vet Res 1998;59:1227–1233)
Effects of buprenorphine on cardiovascular and pulmonary function in clinically normal horses and horses with chronic obstructive pulmonary disease
Authors: Szöke Mihàly O. , Blais Diane , Cuvelliez Sophie G. , Lavoie Jean-Pierre 
Published: January 2024

Abstract

Objectives
To evaluate the cardiovascular and respiratory effects of buprenorphine administered intravenously in clinically normal horses and horses with chronic obstructive pulmonary disease (COPD).

Animals
5 clinically normal horses and 5 horses with COPD that were in partial clinical remission (period A) or were having an acute attack of airway obstruction (period B).

Procedures
Pulmonary function testing, arterial blood gas analysis, and arterial blood pressure measurements were performed before and after a single intravenous bolus of buprenorphine (3 μg/kg of body weight). Respiratory rate (f), tidal volume (VT), expiratory-to-inspiratory time ratio (TE/TI), minute expiratory ventilation (VE), maximal change in transpulmonary pressure (ΔPL), dynamic compliance (Cdyn), and pulmonary resistance (RL) were calculated with a pulmonary function computer. Heart rate (HR) and systolic (SABP), diastolic (DABP), and mean arterial blood pressures (MABP) were measured.

Results
At baseline, COPD horses in period A had decreased Cdyn and increased f, VE, PL, and HR, whereas COPD horses in period B had decreased TE/TI and Cdyn, arterial blood pH, and Po2, and increased f, vE, ΔPL, and RL, compared with clinically normal horses. After drug administration, SABP, DABP, and MABP increased in all horses, f and VE increased in clinically normal horses, and Pao2 decreased within 60 minutes in horses with COPD.

Conclusion and Clinical Relevance
Buprenorphine can induce excitement in unsedated horses or horses that do not have signs of pain, but does not seem to induce severe respiratory depression or adverse cardiovascular effects in clinically normal horses or those with COPD. (Am J Vet Res 1998;59:1287–1291)