bluuebunny/crossref_metadata_2025_split huggingface dataset:
Safety and efficacy of a mutagen-attenuated Rift Valley fever virus vaccine in cattle
Authors: Morrill J. C. , Mebus C. A. , Peters C. J. 
Published: January 2024

Abstract

Objective
To examine safety and efficacy of a mutagen-attenuated Rift Valley fever virus (RVFV) vaccine (RVF MP-12) in cattle.

Animals
38 pregnant cows, 14 steers, and 10 lactating dairy cows.

Procedure
Pregnant cows in their third, fifth, or eighth month of gestation were vaccinated (1 ml of RVF MP-12 containing 5 log10 plaque-forming units [PFU] of virus) and were monitored daily through parturition for signs of disease, viremia, and immunologic response. Additionally, 10 vaccinated pregnant cows were challenge inoculated with virulent RVFV at postvaccination day (PVD) 30 and were monitored daily for untoward effects. Ten unvaccinated pregnant cows also were challenge inoculated with virulent RVFV and served as challenge controls. Vaccinated lactating dairy cows were monitored for viremia and virus shedding in the milk through PVD 14. Yearling steers were vaccinated to assess their immunologic response to various doses of vaccine and were challenge inoculated with virulent RVFV at PVD 28 to assess protection.

Results
10 of 38 (26.3%) cows vaccinated during pregnancy developed transient postvaccination viremia titer ≥ 2.5 log10 PFU/ml of serum. All vaccinated cows delivered live, healthy calves that were RVFV seronegative at birth, but which quickly acquired colostral antibodies. Vaccinated cows and their fetuses were protected when challenge exposed with virulent RVFV at PVD 30, whereas unvaccinated pregnant cows inoculated with RVFV became febrile and viremic, and aborted. Vaccine virus was unsuccessfully sought from milk of lactating dairy cows after vaccination, suggesting that shedding of vaccine virus through milk should not be a concern. Steers, inoculated with tenfold escalating vaccine doses, beginning with 1.0 log10 PFU, were protected against virulent RVFV challenge exposure.

Conclusions
RVF MP-12 may be safe and efficacious for use in pregnant or lactating bovids, and a minimal dose of vaccine may provide suitable protection against viremia. (Am J Vet Res 1997;58:1104–1109)
Safety of a mutagen-attenuated Rift Valley fever virus vaccine in fetal and neonatal bovids
Authors: Morrill J. C. , Mebus C. A. , Peters C. J. 
Published: January 2024

Abstract

Objective
To examine effects of in utero inoculation with a mutagen-attenuated Rift Valley fever virus (RVFV) vaccine (RVF MP-12) on fetal bovids and to assess the safety and efficacy of calfhood vaccination with RVF MP-12.

Animals
18 pregnant Hereford and Hereford-type cows in the third or fifth month of gestation, their progeny, and 25 calves from cows immunized with RVF MP-12 during pregnancy.

Procedure
Bovine fetuses were inoculated, via laparotomy, with 1 ml of RVF MP-12 containing 5 log10 plaque-forming units (PFU) of virus. Blood was obtained from newborn calves prior to their ingestion of colostrum. Immune-naive calves and calves born to RVF MP-12-vaccinated dams, ranging in age from 2 to 45 days, were vaccinated with RVF MP-12, and some were later challenge exposed with 1 ml of 5.7 log10 PFU of virulent RVFV strain ZH-501. Cows were monitored for viremia and antibody responses and for hematologic and serum biochemical alterations through parturition or abortion.

Results
Surviving in utero-vaccinated calves were healthy, with no noticeable defects. Except for 1 vaccine-inoculated fetus that died on postinoculation day 21, all in utero-vaccinated fetuses had serum neutralizing antibody titer ≥ 1:20 at the time of delivery. All dams of in utero-vaccinated fetuses also developed neutralizing antibody titer. Calves born to cows vaccinated during gestation did not have antibody at birth, and all but 1 quickly acquired colostral antibody. Postparturient inoculation of immune-naive calves and calves with colostral antibodies resulted in no untoward effects, and all calves with detectable neutralizing antibodies were protected against virulent virus challenge exposure.

Conclusions
Fetal death and abortion would be rare even if fetuses were exposed to RVF MP-12. The trauma and complications associated with in utero inoculation do not make this a practical method of immunization. RVF MP-12 was safe, immunogenic, and protective in calves as young as 2 days of age. (Am J Vet Res 1997;58:1110–1114)
Evaluation of aspartate transaminase activity and β-hydroxybutyrate concentration in blood as tests for prediction of left displaced abomasum in dairy cows
Authors: Geishauser Thomas , Habil  , Leslie Ken , Duffield Todd , Edge Victoria 
Published: January 2024

SUMMARY

Objectives
To evaluate aspartate transaminase (AST) activity and β-hydroxybutyrate (BHB) concentration in blood obtained during the first or second postpartum (PP) week as tests for prediction of subsequent left displaced abomasum (LDA) diagnosis in dairy cows.

Animals
36 cows with LDA tested at a mean 3 PP days, which was 7 to 22 days prior to LDA diagnosis (25, 75% quantiles), and 28 cows with LDA tested at 10 PP days, which was 5 to 18 days prior to LDA diagnosis, were matched to 3 controls per case by herd and calving date. Data were available from a large field study.

Procedure
Odds ratio, sensitivity, specificity, and likelihood ratio were determined for various AST and BHB cutoff values.

Results
AST, using cutoff values between 100 and 180 U/L, and BHB, using cutoff values between 1,000 and 1,600 μmol/L, were significantly associated with subsequent LDA diagnosis. When cutoff values were increased, odds ratio and likelihood ratio increased; however, sensitivity decreased and specificity increased.

Conclusion and Clinical Relevance
AST activity and BHB concentration in blood obtained during the first or second PP week might be useful as predictors of subsequent LDA diagnosis. (Am J Vet Res 1997;58:1216–1220)
Effects of high-dose gentamicin sulfate on neuromuscular blockade in halothane-anesthetized horses
Authors: Hague Brent A. , Martinez Elizabeth A. , Hartsfield Sandee M. 
Published: January 2024

SUMMARY

Objective
To evaluate effects of a single high dose of gentamicin on neuromuscular function in horses anesthetized with halothane.

Animals
6 healthy adult horses.

Procedure
Halothane-anesthetized horses were positioned in left lateral recumbency, and the right hind limb was immobilized in a reusable fiberglass cast fixed to a steel frame. The hoof was attached to a force transducer, and resting tension of 0.93 ± 0.16 kg was maintained. A supramaximal train-of-four stimulus of 2 Hz for a duration of 0.25 millisecond was applied to the superficial peroneal nerve every 20 seconds by a square-wave stimulator. The force of the evoked digital extensor tension was recorded to determine first muscle twitch tension, compared with the baseline value (T1%) and the ratio of the force of the fourth twitch to the first twitch (T4/T1). Data were recorded at 5, 10, 15, 30, and 60 minutes after IV administration of vehicle or gentamicin (6 mg/kg of body weight).

Results
There was a significant (P = 0.04) treatment-time interaction for the effect of gentamicin on T1%; T1% associated with vehicle decreased from 100% to 92% during the 60- minute study period, but no decrease was associated with gentamicin. For T4/T1, there was no significant effect of treatment or time or treatment-time interaction between gentamicin and vehicle.

Conclusions
Gentamicin did not cause a decrease in initial muscular strength, nor did it impair the muscles’ ability to sustain strength.

Clinical Relevance
A single high dose of gentamicin does not cause significant neuromuscular blockade when administered alone to healthy horses anesthetized with halothane. (Am J Vet Res 1997;58:1324–1326)
Room temperature storage and cryopreservation of canine platelet concentrates
Authors: Allyson Kay , Abrams-Ogg Anthony C. G. , Johnstone Ian B. 
Published: January 2024

SUMMARY

Objective
To determine whether in vitro viability and function, and microbiological sterility, of canine platelet concentrates (PC) could be retained during storage at 20 to 24 C (room temperature [RT]) for up to 7 days and cryopreservation for 6 months.

Animals
14 mature dogs.

Procedure
PC prepared by centrifugation of fresh blood were stored for 7 days at RT with continuous agitation. An aliquot of each was cryopreserved with 6% dimethyl sulfoxide at −74 C for 6 months. Fresh PC (day 0) were tested by microbial culture and measurement of platelet count, mean platelet volume, pH, glucose and lactate concentrations, lactate dehydrogenase activity, response to hypotonic stress, and aggregation. Tests were also performed on PC stored at RT on days 3, 5, and 7, and on the cryopreserved aliquots after thawing.

Results
After 7 days at RT, microbial growth was not evident, and decrease in platelet number was not significant. On the basis of pH and glucose and lactate concentrations, metabolic activity was maintained throughout RT storage. On the basis of mean platelet volume and lactate dehydrogenase activity, platelet swelling and membrane damage had occurred. Aggregatory responses decreased during RT storage, and platelets recovered poorly from hypotonic stress. After cryopreservation for 6 months, microbial growth was not evident, but platelet numbers were significantly decreased. Mean platelet volume and lactate dehydrogenase activity were significantly greater, compared with values for day-0 PC. Crypreserved platelets aggregated poorly and did not respond to hypotonic stress.

Conclusions
Platelet viability and microbiological sterility are retained in canine PC stored for 7 days at RT, but platelet function progressively decreases and day-7 platelets are substantially damaged. Crypreservation of PC results in considerable damage, compared with that of PC stored at RT.

Clinical Relevance
Similar to human PC, canine PC stored at RT for up to 5 days can be recommended for treatment. (Am J Vet Res 1997;58:1338–1347)
Comparison of radiography, magnetic resonance imaging, and surgical findings in dogs with elbow dysplasia
Authors: Snaps F. R. , Balligand M. H. , Saunders J. H. , Park R. D. , Dondelinger R. F. 
Published: January 2024

SUMMARY

Objective
To describe the magnetic resonance imaging (MRI) appearance of medial coronoid process and humeral condyle lesions in dysplastic cubital joints and to compare survey radiography and MRI for evaluation of fragmented medial coronoid process (FMCP) and lesions of the medial aspect of the humeral condyle (MAHC).

Animals
18 dogs with elbow dysplasia.

Procedure
Radiography of 22 cubital joints was performed. The 22 joints then underwent MRI. The scans were evaluated with regard to the shape and signal of the coronoid process; articular cartilage change, subchondral bone disruption of the MAHC. Surgical findings were used as the standard to calculate accuracy, sensitivity, specificity, and positive- and negative-predictive values for specific diagnosis of FMCP (free fragment) and lesions of the MAHC.

Results
At surgery, 31.8% of the joints had FMCP (free), 36.4% had nondisplaced unmineralized coronoid process, and 27.2% had nondisplaced mineralized coronoid process. Eleven joints had lesions of the MAHC, and wear lesions were observed in 41 % of the joints. On radiography, FMCP (free) was visualized in 9% of the joints and lesions of the MAHC were observed in 23%. MRI had the highest accuracy (95.5%), sensitivity (100%), and negative-predictive value (100%) for detection of FMCP (free), and had accuracy (91 %), sensitivity (87.5%), specificity (92.5%), and positive (87.5%)- and negative (92.5%)- predictive values for detection of nondisplaced unmineralized coronoid process.

Conclusions and Clinical relevance
Compared with radiography, MRI was useful for detection of nondisplaced unmineralized coronoid process; images consistently correlated with surgical findings. The technique is accurate and especially useful when radiographic findings are inconclusive. (Am J Vet Res 1997;58:1367–1370)
Infection of bone marrow macrophages by equine infectious anemia virus
Authors: Swardson C. J. , Lichtenstein D. L. , Wang S. , Montelaro R. C. , Kociba G. J. 
Published: January 2024

SUMMARY

Objective
To characterize infection of bone marrow-derived macrophages (BMDM) with equine infectious anemia virus (EIAV) by determining virus production, effects on viability, and induction of cytokines.

Sample Population
BMDM obtained from bone marrow of 6 clinically normal adult horses.

Procedure
BMDM were infected with EIAV at a multiplicity of infection of 8. Cell viability, percentage of cells with detectable viral protein, reverse transcriptase activity, and concentrations of infective virus (focus-forming units/ml), interleukin 6, and tumor necrosis factor-α were measured in culture supernatant samples obtained at various days after infection.

Results
Cell viability was decreased on day 4 and was maximally decreased on day 8. The number of cells with detectable viral protein and supernatant reverse transcriptase activity increased significantly on day 4 and increased until day 6. Virus concentration (focus-forming units per milliliter) peaked on day 4 after infection and was constant thereafter. Infection with EIAV caused significant induction of interleukin 6 production by BMDM. The maximal difference was seen on day 4 after infection. Control and infected BMDM produced only negligible amounts of tumor necrosis factor-α.

Conclusions
BMDM are useful, as a cell population, to study the effects of infection with EIAV, including cell death and induction of interleukin 6 but not tumor necrosis factor-α production. (Am J Vet Res 1997;58:1402–1407)
Comparison of pulsed-field gel electrophoresis and phage typing for discriminating poultry strains of Staphylococcus aureus
Authors: Shimizu Akira , Kawano Junichi , Yamamoto Chikage , Kakutani Osamu , Fujita Manabu 
Published: January 2024

SUMMARY

Objective
To compare pulsed-field gel electrophoresis (PFGE) patterns of Staphylococcus aureus from chickens in England, Belgium, Bulgaria, Argentina, and Japan, to assess the value of PFGE for discriminating strains, and to compare results obtained by PFGE with those obtained by biotyping and phage typing.

Sample Population
78 S aureus isolates from diseased and healthy chickens.

Procedure
Chromosomal DNA of S aureus was digested with restriction endonuclease Sma l, and fragments were separated by PFGE in 1 % agarose gel.

Results
All 78 strains from 5 countries were classified as poultry ecovar according to a previously established biotyping system. Chromosomal DNA was cut by Sma l into 18 to 23 fragments ranging from about 3 to 685 kb. Seventy-eight strains produced 15 types, arbitrarily designated A to O, and 45 subtypes. Some differences were observed in PFGE patterns among countries. However, 10 fragments (333, 190, 110, 63, 55, 42, 34, 19, 10, and 3 kb) were highly conserved and were shared by almost all (> 78%) of the strains examined. The PFGE patterns were compared with those obtained by phage typing. All 29 strains belonging to avian phage-group II produced type A and 19 subtypes. Of the 15 strains belonging to phage-group I, 11 produced 8 types (B to H, O) and 5 subtypes that were different from those of type A.

Conclusions
Genomic DNA fingerprinting by PFGE is an effective technique for discriminating poultry S aureus strains and appears to be a useful method for subtyping strains of avian phage groups or the poultry-specific ecovar. (Am J Vet Res 1997;58:1412–1416)
Effect of low-dose atropine administration on dobutamine dose requirement in horses anesthetized with detomidine and halothane
Authors: Weil Ann B. , Keegan Robert D. , Greene Stephen A. 
Published: January 2024

SUMMARY

Objective
To determine whether a low dose of atropine is associated with decreased requirement for cardiovascular supportive treatment in horses given detomidine prior to maintenance of general anesthesia with halothane.

Animals
3 groups of 10 healthy horses.

Procedure
Detomidine (20 μg/kg of body weight, IM) was administered to all 30 horses. Then, 10 horses received atropine (0.006 mg/kg, IV) 1 hour after detomidine administration, 10 horses received atropine (0.012 mg/kg, IM) at the time of detomidine administration, and 10 horses served as a control group. Heart rate was measured prior to detomidine administration and at fixed intervals throughout anesthesia. The dobutamine infusion rate necessary to maintain mean arterial blood pressure between 70 and 80 mm of Hg was recorded. Systemic blood pressures, end-tidal halothane, end-tidal CO2, and arterial blood gas tensions were measured at fixed intervals.

Results
Mean heart rate was higher among horses receiving atropine IV or IM, compared with that in control horses. Horses that received atropine IV had higher systemic arterial blood pressure and required a lower dobutamine infusion rate than did horses of the other groups.

Conclusion
Detomidine-treated, halothane-anesthetized horses given atropine IV required less dobutamine, compared with horses receiving or not receiving atropine IM. Complications, such as colic and dysrhythmias, from use of higher doses of atropine, were not observed at this lower dose of atropine.

Clinical Relevance
IV administration of a low dose of atropine prior to induction of general anesthesia may result in improved blood pressure in horses that have received detomidine before anesthesia with halothane. (Am J Vet Res 1997;58:1436–1439)
Effects of medetomidine on serum insulin and plasma glucose concentrations in clinically normal dogs
Authors: Burton Shelley A. , Lemke Kip A. , Ihle Sherri L. , Mackenzie Allan L. 
Published: January 2024

SUMMARY

Objective
To determine the effects of medetomidine, administered IV, on serum insulin and plasma glucose concentrations in clinically normal dogs.

Animals
6 healthy adult Beagles.

Procedure
Dogs were randomly assigned to each of 3 treatments in a prospective cross-over study design. Serum insulin and plasma glucose concentrations were determined before and 20, 40, 60, 120, 180, 240, 300, 360, 420, and 480 minutes after IV administration of 0.9% NaCI solution (control) or medetomidine (10 or 20 μg/kg of body weight).

Results
Mean serum insulin concentration decreased after medetomidine administration and was significantly (P ≤ 0.05) lower than control values 20, 40, 60, and 120 minutes after drug administration. Mean plasma glucose concentration tended to increase after medetomidine administration, but did not differ significantly from control values.

Conclusions
In dogs, IV administration of medetomidine at dosages of 10 and 20 μg/kg transiently decreases serum insulin concentration, but plasma glucose concentration remains within the normal physiologic range.

Clinical Relevance
Medetomidine can be given at low, preanesthetic dosages without significantly altering plasma glucose concentration in clinically normal dogs. (Am J Vet Res 1997;58:1440–1442)
Exercise capacity in young and old mares
Authors: McKeever Kenneth Harrington , Malinowski Karyn 
Published: January 2024

SUMMARY

Objective
To test the hypothesis that, compared with unfit young horses, unfit older horses have lower aerobic capacity and reduction in other indices of exercise capacity.

Animals
6 young (mean ± SEM, 5.3 ± 0.8 years and 445 ± 13 kg) and 6 aged (22.0 ± 0.4 years and 473 ± 18 kg) healthy Standardbred and Thoroughbred mares.

Procedures
The mares, accustomed to running on a treadmill, were tested by use of an incremental exercise test. None of the mares had received exercise training for at least 4 months prior to the study. During testing, mares ran up a fixed 6% grade, starting at a speed of 4 m/s, with 1 m/s increase every 60 seconds (omitting 5 m/s) until they reached fatigue. Maximal oxygen uptake (VO2max) was measured by use of an open-flow calorimeter. Venous blood samples (10 ml) were collected during the last 10 seconds of each step and were used to measure blood lactate concentration and PCV. Calculated performance indices included velocity at VO2max, maximal velocity, and velocity at lactate concentration of 4 mmol/L; work rate (watts) at those velocities also was determined.

Results
There were differences (P < 0.05) between old and young mares for maximal run velocity attained during the test (8.7 ± 0.5 versus 10.8 ± 0.5 m/s, respectively), VO2max (89.4 ± 4.3 versus 117.3 ± 9.5 ml/kg of body weight/min, respectively), and velocity at VO2max (8.0 ± 0.4 versus 9.8 ± 0.7 m/s, respectively). Also, velocity required to reach blood lactate concentration of 4 mmol/L was lower (P < 0.05) in old (7.5 ± 0.4 m/s), compared with young (10.2 ± 0.7 m/s), mares.

Conclusion
Older mares have substantially (−24%) lower maximal aerobic capacity than do young mares.

Clinical Relevance
Many horses participate in athletic activities into their late teens and some do so beyond the age of 20 years; thus, the need exists to explore ways to adjust training programs for older horses. (Am J Vet Res 1997;58:1468–1472)
Cardiorespiratory effects of sevoflurane, isoflurane, and halothane anesthesia in horses
Authors: Grosenbaugh D. A. , Muir W. W. 
Published: January 2024

SUMMARY

Objective
To determine and compare cardiorespiratory and recovery effects of sevoflurane, isoflurane, and halothane in horses.

Animals
8 clinically normal horses (4 mares, 4 geldings), 5 to 12 years old.

Procedure
Inhalation anesthesia was maintained for 90 minutes with sevoflurane, isoflurane, or halothane. Anesthesia depth was maintained at 1.5 minimum alveolar concentration of halothane, isoflurane, and sevoflurane, then was reduced at 30 and 60 minutes. A surgical plane of anesthesia was reinduced by administration of ketamine or thiopental or by increasing the fractional inspired concentration of sevoflurane. Cardiovascular and pulmonary variables were recorded and compared among inhalation anesthetics. Recovery was monitored, and subjective assessment of recovery quality was performed.

Results
Hemodynamic and pulmonary indices during sevoflurane anesthesia were similar to those of isoflurane. Cardiac output and systemic arterial pressure decreased less during sevoflurane and isoflurane anesthesia than during halothane anesthesia. After 90 minutes, cardiac output was greater for sevoflurane and isoflurane, respectively, compared with halothane. Mean arterial pressure was similar for all thre anesthetic agents. Respiratory rate for sevoflurane and isoflurane was less than that for halothane. This apparent respiratory depression correlated with greater increase in Paco2 and decreased pH when sevoflurane and isoflurane were compared with halothane. Recovery from sevoflurane anesthesia was qualitatively similar and superior to recovery from isoflurane and halothane, respectively. Time to standing did not differ significantly between sevoflurane and isoflurane, but was shorter than halothane.

Conclusions
Sevoflurane induced cardiorespiratory effects that were comparable to those of isoflurane and halothane. Cardiac output was greater and respiratory rate was less than that for halothane at 1.5 MAC. Sevoflurane anesthesia was characterized by good control of anesthesia depth during induction, maintenance, and recovery. Recovery time after sevoflurane anesthesia was comparable to that for isoflurane, and recovery was smooth and controlled in a manner consistent with recovery from halothane. (Am J Vet Res 1998;59:101–106)