bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiac electrophysiologic measurements in dogs before and after intravenous administration of atropine and propranolol
Authors: Wright Kathy N. , Hines Debrah A. , Bright Janice M. 
Published: January 2024

Abstract

Objectives
To assess baseline cardiac electrophysiologic (EP) measurements in dogs undergoing a clinically used anesthetic protocol, and to study the effects of IV administered atropine and propranolol on these EP variables.

Animals
15 adult dogs with cardiac function within reference ranges, as assessed by physical examination, electrocardiography, and echocardiography.

Procedure
13 cardiac EP variables were measured in isofluorane-anesthetized dogs before and after IV administration of atropine and propranolol. Multipolar electrode catheters were positioned against the endocardium of the dorsal portion of the right atrium, His bundle region, and right ventricular apex. Incremental pacing and pacing-extrastimulus techniques were used to obtain EP measurements of the sinoatrial node, atrioventricular node, and atrial and ventricular myocardia in the control state and after IV administration of 0.04 mg of atropine and 0.2 mg of propranolol/kg of body weight.

Results
Only the atrial effective refractory period changed significantly after muscarinic and β-adrenergic receptor antagonism. Marked individual variation in response to these agents, however, was apparent. Two dogs had substantial decreases in sinoatrial and/or atrioventricular nodal measurements, and 7 dogs had notable increases in atrioventricular nodal measurements.

Conclusions
Cardiac EP measurements vary widely among clinically normal, isofluorane-anesthetized dogs. Individual dogs can have variable degrees of autonomic tone, which can be minimized by pharmacologic receptor antagonism.

Clinical Relevance
Although effects of receptor antagonism at clinically applicable dosages were not significant for 12 of 13 measurements, withdrawal of vagal tone can induce marked EP changes and may be important during a clinical study. (Am J Vet Res 1996;57:1695–1701)
Investigation of an outbreak of Aleutian disease on a commercial mink ranch
Authors: Jackson M. Keven , Winslow Scott G. , Dockery Larry D. , Jones Jedd K. , Sisson Donald V. 
Published: January 2024

Abstract

Objective
To determine the modes of transmission of Aleutian mink disease in a natural outbreak.

Animals
5,580 black and 9,087 brown mink from a ranch with an outbreak of Aleutian mink disease.

Procedure
Each mink had serum tested by counter-electrophoresis for Aleutian disease antibody. If a mink was seropositive for Aleutian disease virus by counter-electrophoresis, it was considered to be infected. Correlation of prevalence of the disease in kits and parents was determined. Spatial arrangement of infected and uninfected mink also was studied.

Results
Infected black dams were more likely to produce infected kits than were uninfected dams. In contrast, infected black sires were less likely to produce infected kits than were uninfected sires. In brown mink, in which prevalence of Aleutian disease was lower, transmission from infected dams and sires to kits was apparent. Infected black mink appeared to be more efficient in transmitting the disease horizontally than were infected brown mink. Although the spatial arrangement of infected mink indicated that mechanical transmission of the disease may be the most efficient mode of horizontal transmission, airborne transmission also occurred.

Conclusions and Clinical Relevance
Infected sires with nonprogressive Aleutian disease may confer protection to their kits in the face of a severe outbreak. Brown mink may be less able to transmit the virus horizontally than are black mink. Airborne transmission is substantial, but may not be as efficient as mechanical transmission. (Am J Vet Res 1996;57:1706–1710)
Cardiopulmonary and gastrointestinal motility effects of xylazine/ketamine-induced anesthesia in horses previously treated with glycopyrrolate
Authors: Singh Sukhpal , McDonell Wayne N. , Young Simon S. , Dyson Doris H. 
Published: January 2024

Abstract

Objective
To assess the usefulness of glycopyrrolate (GLY) in preventing the decrease in cardiac index (Cl) usually caused by xylazine (XYL)/ketamine (KET)-induced anesthesia in horses.

Animals
6 healthy horses.

Procedure
Horses were treated with saline solution or 2.5 μg of GLY/kg of body weight, administered IV. 15 minutes later, XYL (1 mg/kg) was administered IV followed 5 minutes later by KET (2 mg/kg) administration. The horses were positioned in left lateral recumbency, insufflated with 15 L of oxygen/min, and maintained for 30 minutes on the infusion of 0.05 mg of XYL and 0.1 mg of KET/kg/min. Mean, systolic, and diastolic arterial blood pressures, mean pulmonary arterial and central venous pressures, heart rate, Cl, and arterial and mixed venous blood gas tensions were recorded up to 40 minutes after anesthesia induction. Intestinal motility was assessed by auscultation of 4 abdominal quadrants for 24 hours after induction. Data were analyzed by Wilcoxon's rank-sum test for nonparametric observations, and by ANOVA for repeated measures and Scheffe's test for continuous parametric variables.

Results
Horses given GLY had significantly higher heart rate; mean, systolic, and diastolic arterial blood pressures; Cl; oxygen delivery; and mixed venous oxygen tensions, with significantly less tissue oxygen extraction, compared with saline-treated horses. Both groups had complete loss of intestinal motility associated with general anesthesia.

Conclusions
GLY significantly reduced the cardiovascular dysfunction attributable to general anesthesia with XYL and KET. The return of intestinal motility was delayed by 3 to 6 hours without causing any serious side effects. (Am J Vet Res 1996;57:1762–1770)
Resynthesis of glycogen in skeletal muscle from Standardbred trotters after repeated bouts of exercise
Authors: Hyyppä Seppo , Räsänen Leena A. , Pösö A. Reeta 
Published: January 2024

Abstract

Objective
To determine glycogen resynthesis rate and changes in plasma metabolite concentrations in horses before and after repeated exercise.

Animals
6 clinically normal Standardbred trotters.

Procedure
Horses trotted distances of 3,000, 3,000, and 2,000 m (trial A) and 3 days later, trotted 2, 100, 2, 100, and 1,600 m (trial B). Horses had 1 hour rest periods between bouts of exercise. Trotting speed was increased with each exercise bout, up to a near maximal. Muscle biopsy specimens and venous blood samples were obtained before each trial and 0, 4, 24, 48, and 72 hours after the third bout. Blood samples were also taken between exercise bouts. Muscle glycogen content and plasma glucose, glycerol, nonesterified fatty acid, and triglyceride concentrations were determined.

Results
Muscle glycogen content was significantly decreased immediately after exercise from 473 ± 45 to 329 ± 79 mmol/kg of dry weight in trial A, and from 472 ± 128 to 347 ± 59 mmol/kg in trial B. Further decreases were measured 4 hours after exercise. Glycogen resynthesis was negligible 24 hours after exercise. Basal muscle concentrations of glycogen were obtained 72 hours after exercise in trial A (472 ± 128 mmol/kg), but not in trial B (279 ± 52 mmol/kg). Plasma concentrations of glucose were greater than or equal to before-exercise values. Plasma concentrations of lipid metabolites, glycerol, triglycerides, and nonesterified fatty acids, were less than before-exercise values 2 to 72 hours after exercising.

Conclusions
Repeated bouts of exercise decrease glycogen repletion rate, which is not attributable to hypoglycemia, but may be influenced by limited availability of lipids for energy production. (Am J Vet Res 1997;58:162–166)
Skeletal muscle characteristics and metabolic response to exercise in young Standardbreds
Authors: Ronéus N. , Essén-Guslavsson B. 
Published: January 2024

Abstract

Objective
To determine whether performance capacity in a group of young trained Standardbreds is related to skeletal muscle characteristics and metabolic response to exercise.

Animals
13 clinically normal 2-year-old Standardbreds.

Procedure
Venous blood and middle gluteal muscle biopsy samples were obtained from each horse within 1 to 2 minutes after trotting at high speed for 1,600 m.

Results
There was a positive correlation between plasma lactate and muscle glucose-6-phosphate (G-6-P) concentrations and trotting speed. There was a negative correlation between muscle adenosine triphosphate concentration and trotting speed, plasma lactate concentration, and muscle lactate and G-6-P concentrations. Muscle concentration of G-6-P was positively correlated with muscle lactate and plasma lactate concentrations. Percentage of type-1, -2A, and -2B fibers in skeletal muscle and muscle enzyme activities of hexokinase, 3-OH-acyl-CoA dehydrogenase, lactate dehydrogenase, and citrate synthase were not correlated with trotting speed.

Conclusion
Speed of trotting at a distance of 1,600 m in young trained Standardbreds is related to the ability of muscle to produce energy by use of anaerobic glycolysis. (Am J Vet Res 1997;58:167–170)
Use of dew-point hygrometry, direct sweat collection, and measurement of body water losses to determine sweating rates in exercising horses
Authors: Kingston Janene K. , Geor Raymond J. , McCutcheon L. Jill 
Published: January 2024

Abstract

Objective
To compare dew-point hygrometry, direct sweat collection, and measurement of body water loss as methods for determination of sweating rate (SR) in exercising horses.

Animals
6 exercise-trained Thoroughbreds.

Procedure
SR was measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km, with a 15-minute rest at the end of each 15-km phase. Each horse completed 2 exercise trials. Dew-point hygrometry, as a method of local SR determination, was validated in vitro by measurement of rate of evaporative water loss. During exercise, local SR was determined every 10 minutes by the following 2 methods: (1) dew-point hygrometry on the neck and lateral area of the thorax, and (2) on the basis of the volume of sweat collected from a sealed plastic pouch attached to the lateral area of the thorax. Mean whole body SR was calculated from total body water loss incurred during exercise.

Results
Evaporation rate measured by use of dewpoint hygrometry was significantly correlated (r2 = 0.92) with the actual rate of evaporative water loss. There was a similar pattern of change in SR measured by dew-point hygrometry on the neck and lateral area of the thorax during exercise, with a significantly higher SR on the neck. The SR measured on the thorax by direct sweat collection and by dew-point hygrometry were of similar magnitude. Mean whole body SR calculated from total body water loss was not significantly different from mean whole body SR estimated from direct sweat collection or dew-point hygrometry measurements on the thorax.

Conclusions
Dew-point hygrometry and direct sweat collection are useful methods for determination of local SR in horses during prolonged, steady-state exercise in moderate ambient conditions. Both methods of local SR determination provide an accurate estimate of whole body SR. (Am J Vet Res 1997;58:175–181)
Pregnancy-associated changes in material properties of the third metacarpal cortical bone in mares
Authors: Hawkins Dan L. , Stover Susan M. 
Published: January 2024

Abstract

Objective
To investigate the effect of late gestation, age, and parity on material properties of third metacarpal (MCIII) cortical bone in mares.

Animals
8 healthy mares (treatment group) that died or were euthanatized within 24 hours after parturition because of foaling complications and 6 age-matched, healthy, nonpregnant mares (control group).

Procedures
After random assignment for mechanical testing and microradiography, the dorsal half of transverse mid-diaphyseal sections of each MCIII bone was divided into lateral, dorsal, and medial regions. Cylinders of bone from each of the 3 regions were tested in compression in a single cycle to failure. Contact microradiographic views were taken of 100-µm-thick sections prepared from methylmethacrylate-embedded transverse dorsal region specimens, which were further divided into periosteal, intracortical, and endosteal regions for assessment of bone mineral density and porosity.

Results
Postpartum mares had lower yield strain in the dorsal and medial regions and failure strain in the medial region. Increasing parity was associated with decreasing elastic modulus in the dorsal region and yield stress and failure stress in the lateral region. Age and parity were positively correlated (r = 0.865; P = 0.0001), but significant correlations were not found between treatment group and age or between treatment group and parity. Increasing age and parity were associated with increasing porosity in the periosteal region.

Conclusions and Clinical Relevance
On the basis of the material properties evaluated for MCIII cortical bone in late pregnancy, any increased risk for fractures in mares in late gestation may be related to parity or age or both, and less likely to pregnancy per se. (Am J Vet Res 1997;58:182–187)
Effects of anesthesia of the palmar digital nerves on kinematic gait analysis in horses with and without navicular disease
Authors: Keegan Kevin G. , Wilson Daniel J. , Wilson David A. , Frankeny Rebecca L. , Loch Wayne E. , Smith Bryan 
Published: January 2024

Abstract

Objective
To determine the effect of local anesthesia of the palmar digital nerves on forelimb kinematics in Quarter Horses with and without navicular disease.

Animals
12 adult Quarter Horses; 5 clinically normal (sound) and 7 with navicular disease.

Procedure
Kinematic measurements were made on adult horses trotting on a treadmill, before and after palmar digital nerve block (PDNB). Twenty-three displacement, joint angle, and temporal gait measurements of the right forelimb and head were made for 5 strides in each horse. Initial (before local anesthesia) right forelimb measurements were obtained after a left forelimb PDNB. Kinematic measurements were compared before and after PDNB of the right forelimb by multiple ANOVA with an α = 0.05, adjusted for posthoc comparisons by Bonferroni correction.

Results
In sound horses, the only significant change in kinematic measurements after PDNB nerve block was in the maximum extension of the metacarpophalangeal joint at mid-stance, which was decreased by an angle of 2°. In horses with navicular disease, mean maximum extension of the metacarpophalangeal joint during stance phase and maximum flexion of the carpal joint during swing phase were significantly increased after PDNB. Also, total stance phase, cranial stance phase, and breakover durations were significantly shorter. In horses with navicular disease, differences between minimum head heights during stance phase of each forelimb and total vertical head excursion during a complete stride were significantly smaller after PDNB.

Conclusion
Several kinematic measurements of gait can be used to determine improvement of lameness in horses with navicular disease after PDNB block while trotting on a treadmill. (Am J Vet Res 1997; 58:218–223)
Effect of amount and type of dietary fiber on food intake in energy-restricted dogs
Authors: Butterwick R. F. , Markwell P. J. 
Published: January 2024

Abstract

Objective
To evaluate the effect of adding different amounts of insoluble (IF) or soluble (SF) dietary fiber to a commercial diet formulated for weight reduction on satiety and perception of hunger in dogs.

Animals
6 adult dogs.

Procedure
Test diets included 2 low-fiber control diets (CL1 and CL2), 2 diets with increased amount of IF (IF1 and IF2), and 2 diets with increased amount of SF (SF1 and SF2). Each test diet was fed for 12 days to 6 dogs in a Latin square design, and in amounts that correspond to the food allowance recommended for weight reduction. Behavioral characteristics of dogs were recorded for 30-minute periods after introduction of test diets. On 2 occasions during each test period, exactly 3 hours after feeding of the test diet, dogs were given a challenge meal consisting of a standard commercial canned dog food ad libitum. At the end of each 12-day feeding period, all dogs entered a 6-day washout period in which they were offered a standard commercial canned dog food ad libitum.

Results
Diet had no significant effect on intake of the challenge meal, intake of food during the subsequent washout period, or perception of hunger, as represented by behavioral characteristics during the 30-minute period after presentation of test diets. In addition, diet had no significant effect on percentage of weight loss.

Conclusions
Inclusion of high amounts of IF or SF in a commercial low-energy diet has no apparent beneficial effects on satiety when fed to dogs on an energy intake regimen corresponding to allowances for weight reduction. (Am J Vet Res 1997;58:272–276)
Efficacy of doramectin for treatment of experimentally induced infection with gastrointestinal nematodes in calves
Authors: Couvillion C. Edward , Pote Linda M. W. , Siefker Carla , Logan Nigel B. 
Published: January 2024

Abstract

Objective
To determine the efficacy of injectable doramectin against experimentally induced infections with adult and larval (L4) stages of gastrointestinal nematodes in calves.

Procedures
In each experiment, between 20 (experiments 1 and 2) and 30 (experiment 3) parasite-free yearling calves were selected and allotted to groups of 10/group. All calves received oral inoculation of the following infective larval stages of these nematode species: Cooperia onchophora, C punctata, C zurna-bada, Cooperia spp, Haemonchus placei, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei and T colubriformis. Infections or treatments were timed so that, by day of treatment, the population of each parasite species had matured to the stage to be tested (adult or L4). On day of treatment, calves received doramectin (200 µg/kg of body weight, SC), and infected nonmedicated control calves received saline solution SC at the same time. All calves were slaughtered at least 14 days after treatment.

Results
Efficacy against the following adult and L4 species was ≥ 99%: C onchophora, C punctata, C zurnabada, Cooperia spp, H placei, Oes radiatum, O ostertagi, and T colubriformis. Doramectin was also 100% efficacious against the L4 stage of T axei. Efficacy against the adult and L4 stages of N helvetianus was 9.6 and 77.4 to 83.3%, respectively.

Conclusions
Doramectin, at a dosage of 200 µg/kg, is effective in controlling the prevalent gastrointestinal nematodes (adult and L4 stages) found in naturally infected calves.

Clinical Relevance
Doramectin, a new anthelmintic, was effective against recent field strains of the most prevalent gastrointestinal parasites found in cattle in the United States, and could provide another alternative for control of these parasites, (Am J Vet Res 1997;58:282–285)
Safety and immunogenicity of Brucella abortus strain RB51 vaccine in pregnant cattle
Authors: Palmer Mitchell V. , Olsen Steven C. , Cheville Norman F. 
Published: January 2024

Abstract

Objective
To determine the safety and immunogenicity of Brucella abortus strain RB51 as a vaccine in pregnant cattle.

Animals
12 Polled Hereford heifers obtained from a brucellosis-free herd and bred on site at 16 months of age to a brucellosis-free bull.

Procedure
Pregnant heifers were vaccinated at 6 months’ gestation with 109 colony-forming units of B abortus strain RB51 (n = 5), 3 × 108 colony-forming units of B abortus strain 19 (n = 5), or sterile pyrogen-free saline solution (n = 2). Samples were periodically collected for serologic testing and lymphocyte blastogenesis assays. At full gestation, heifers were euthanatized and specimens were collected for bacteriologic culture, histologic analysis, and lymphocyte blastogenesis assay, using various antigenic stimuli.

Results
None of the strain RB51- or strain 19-vaccinates aborted or had gross or microscopic lesions at necropsy that were consistent with brucellosis. Maternal blood mononuclear cells from strain RB51- and strain 19-vaccinates had proliferative responses to γ-irradiated strain RB51 and strain 19 that were greater than responses by cells from nonvaccinated controls. In contrast, maternal superficial cervical lymph node cells from strain 19-vaccinates had proliferative responses to γ-irradiated strain RB51 or strain 19 bacteria greater than those of cells from RB51-vaccinates and nonvaccinated controls. None of the heifers vaccinated with strain RB51 developed antibodies detected by use of the standard tube agglutination test, but all developed antibodies to strain RB51 that reacted in a dot ELISA, using irradiated strain RB51 as antigen.

Conclusions
Pregnant cattle can be safely vaccinated with strain RB51 without subsequent abortion or placentitis. Furthermore, strain RB51 is immunogenic in pregnant cattle, resulting in humoral and cell-mediated immune responses, but does not interfere with serologic diagnosis of field infections. (Am J Vet Res 1997;58:472–477)
Effects of certain vasoactive agents on the long-term pattern of blood pressure, heart rate, and motor activity in cats
Authors: Brown Scott A. , Langford Kimberly , Tarver Stacy 
Published: January 2024

Abstract

Objective
To determine whether a diurnal pattern exists in cardiovascular variables and motor activity, and whether pharmacologic agents that decrease (angiotensin converting enzyme inhibitor) or increase (Nω-nitro-L-arginine methyl ester [L-NAME]) blood pressure alter the pattern.

Animals
6 clinically normal cats.

Procedure
Radiotelemetric implants were used to measure systemic arterial pressure, heart rate, and motor activity in conscious cats maintained in cages. Measurements were obtained during absence of treatment (control), treatment with dietary salt restriction plus an inhibitor of angiotensin converting enzyme (2.5 mg of lisinopril, PO, daily) and treatment with an inhibitor of nitric oxide production (0.1% L-NAME in the drinking water).

Results
A diurnal pattern in arterial pressure and motor activity was observed, with highest values obtained during presence of laboratory personnel. Mean values for arterial pressure obtained during light hours varied from those obtained during darkness (P < 0.05), but by < 3 mm of Hg. Dietary sodium restriction did not have an appreciable effect on arterial pressure, but the combined administration of a low sodium diet plus lisinopril decreased (P < 0.05) measured indices of arterial pressure. Administration of L-NAME increased arterial pressure (P < 0.05) and altered its diurnal pattern.

Conclusions
Although a diurnal pattern of arterial pressure was observed, variations were mostly associated with presence of human beings. Administration of L-NAME, but not lisinopril, altered this diurnal pattern.

Clinical Relevance
Factors that modify arterial pressure may alter the diurnal pattern of cardiovascular variables. In measuring arterial pressure in cats, the effects of human contact may artifactually increase such variables. (Am J Vet Res 1997;58:647–652)