bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular, clinical, and pathologic comparison of two distinct strains of Haemobartonella felis in domestic cats
Authors: Foley Janet E. , Harrus Shimon , Poland Amy , Chomel Bruno , Pedersen Niels C. 
Published: January 2024

Abstract

Objective
To characterize 2 strains of Haemobartonella felis by use of molecular techniques.

Animals
35 specific-pathogen-free cats, 6 months to 4 years old.

Procedure
Intraperitoneal or IV inoculation with blood containing H felis small form (Hfsm, 18 cats) or H felis large form (Hflg, 11 cats); 6 cats were uninfected controls. Hfsm was evaluated for capability to cross-protect against the more virulent Hflg. Morphology of both strains was compared by light microscopy of Wright-Giemsa-stained blood smears, and the 16S rRNA genes were sequenced.

Results
Infection with Hflg induced signs of depression, fever, and severe macrocytic normochromic anemia with nucleated erythrocytes. More than 95% of erythrocytes were parasitized. Inoculation with Hfsm and uninfected control blood induced mild or no clinical signs and no hematologic abnormalities. Anti-Hfelis lgG was first detected on postinoculation day (PID) 21, and increased to maximal titer of 400 by PID 28. Reactivated infection was observed in 8 of 29 cats (4 Hfsm and 4 Hflg), with 5% parasitized erythrocytes during the later attack. On PID 8, Hflg-inoculated cats had positive results of polymerase chain reaction analysis (PCR) that persisted until cats were treated with doxycycline or oxytetracycline; Hfsm-inoculated cats had positive PCR results that persisted for duration of observation (3 months).

Conclusions
Genetically and morphologically distinct strains of H felis infect cats in the field. The level of genetic difference suggested that these strains may be different species or genera.

Clinical Relevance
PCR is a critical diagnostic aid to detect occult Haemobartonella spp infection, as well as response to treatment and clearance of the organism. (Am J Vet Res 1998;59:1581-1588)
Effect of high-intensity exercise on arterial blood gas tensions and upper airway and cardiac function in clinically normal Quarter Horses and horses heterozygous and homozygous for hyperkalemic periodic paralysis
Authors: Maxson-Sage A. , Parente E. J. , Beech J. , Lindborg S. , May L. L. , Teleis D. C. 
Published: January 2024

Abstract

Objective
To determine the effect of exercise on arterial blood gas tensions and upper airway and cardiac function in clinically normal Quarter Horses and horses heterozygous and homozygous for hyperkalemic periodic paralysis (HYPP).

Animals and Procedure
5 clinically normal Quarter Horses, and 5 heterozygous and 2 homozygous HYPP-affected horses were examined before, during, and after exercise on a high-speed treadmill. Arterial blood gas tensions, ECG, and echocardiogram were obtained prior to exercise. Upper airway endoscopy, collection of arterial blood samples, and continuous electrocardiography were performed during a high-intensity stepwise exercise test. An ECG was obtained within 1 minute after completion of the final step.

Results
None of the horses homozygous or heterozygous for HYPP had signs of weakness or muscle fasciculations before, during, or after exercise. Horses homozygous for HYPP had intermittent laryngospasm, dynamic pharyngeal collapse, and appreciable hypoxemia, hypercapnia, and ventricular premature contractions during exercise. Heterozygous and clinically normal horses did not have any abnormalities. Potassium concentration increased significantly above the baseline reference range during exercise in all groups of horses.

Conclusions
Horses homozygous for HYPP had laryngospasm and dynamic pharyngeal collapse associated with exercise, most likely secondary to increase in potassium concentration. Upper airway dysfunction is the most likely cause of hypoxemia and hypercapnia. Cardiac arrhythmias were most likely caused by a combination of hypoxemia and hyperkalemia. (Am J Vet Res 1998;59:615–618)
Hemodynamic effects of thyroidectomy in sedentary horses
Authors: Vischer Carol M. , Foreman Jonathan H. , Constable Peter D. , Benson G. John , Kline Kevin H. , Freeman David E. , Campbell Karen L. , Grubb Tamara L. 
Published: January 2024

Abstract

Objective
To investigate hemodynamic effects of thyroidectomy in horses at rest.

Animals
6 healthy aged Quarter Horse mares.

Procedure
Horses were monitored for 5 months before and 4 weeks after thyroidectomy and for an additional 4 weeks after administration of thyroid hormone supplement (2.5 µg of thyroxine/kg of body weight, PO, q 12 h, and 0.6 µg of triiodothyronine/kg, PO, q 12 h). Responses to thyroid-stimulating hormone (TSH) were measured before and 4 weeks after thyroidectomy. Other variables monitored daily were resting rectal temperature (T), heart rate (HR), respiratory rate (RR), and body weight (BW), Monthly cardiac output (Q), blood volume (BV), plasma volume (PV), standard electrocardiographic measures, systolic and right ventricular blood pressure, and HR responses were determined after IV administration of isoproterenol and phenylephrine. Variables were analyzed by use of repeated-measures ANOVA.

Results
Complete thyroidectomy was confirmed by minimal response to TSH 4 weeks after surgery. Resting HR, RR, T, Q, and β-adrenergic responsiveness to isoproterenol decreased significantly after thyroidectomy. Resting T, Q, and β-adrenergic responsiveness increased after administration of supplement and was not significantly different from euthyroid values. Blood volume and PV increased significantly after thyroidectomy but did not return to euthyroid values despite administration of supplement. Response to phenylephrine was minimally different between treatments.

Conclusions and Clinical Relevance
Thyroidectomy in horses caused decreased resting HR, RR, T, Q, and isoproterenol responsiveness and increased BV, PV, PQ interval, and QT interval corrected for HR. Some of these surgically induced changes appeared to be partially reversed by administration of thyroid hormone supplement. (Am J Vet Res 1999;60:14–21)
Regulation of α-melanocyte-stimulating hormone secretion from the pars intermedia of domestic cats
Authors: Kemppainen Robert J. , Peterson Mark E. 
Published: January 2024

Abstract

Objective
To identify factors regulating secretion of α-melanocyte-stimulating hormone (α-MSH) from the pars intermedia (PI) of the pituitary gland of cats.

Animals
28 healthy adult cats.

Procedure
Indwelling catheters were placed in 1 jugular vein of each of 7 to 10 cats, depending on treatment group. Sixteen hours later, 3 blood samples were collected for determination of baseline plasma hormone concentrations, and saline solution or a test substance (haloperidol, corticotropin-releasing hormone, bromocriptine, isoproterenol, insulin, or dexamethasone) was administered via the catheter. Subsequent blood samples were collected at regular intervals for up to 240 minutes after injection. Concentrations of ACTH, cortisol, and α-MSH were measured in plasma by use of specific radioimmunoassays. Cats were rested for at least 3 weeks between experiments.

Results
Administration of haloperidol and isoproterenol resulted in increased, and bromocriptine and insulin in decreased, circulating concentrations of α-MSH from baseline. ACTH and plasma cortisol concentrations increased after administration of all test substances except dexamethasone. Dexamethasone injection resulted in decreased plasma concentrations of ACTH and cortisol.

Conclusions
Secretion of α-MSH from the PI of cats appears to be inhibited by dopaminergic activity and stimulated by β-adrenergic influences. Activation of secretion of α-MSH from the PI can be dissociated from activation of secretion of other proopiomelanocortin-derived peptides, such as ACTH, arising from the pars distalis. Regulation of secretory activity of the PI of cats resembles that of rats. (Am J Vet Res 1999;60:245–249)
Purification and biochemical characterization of equine pulmonary surfactant protein D
Authors: Hobo Seiji , Ogasawara Yoshinori , Kuroki Yoshio , Akino Toyoaki , Yoshihara Toyohiko 
Published: January 2024

Abstract

Objective
To characterize surfactant protein D (SP-D) isolated from bronchoalveolar lavage fluid (BALF) of healthy horses.

Sample Population
BALF from 10 Thoroughbreds (5 males, 5 females; 26 to 40 months old) without history or clinical signs of respiratory tract disease.

Procedure
BALF was obtained and centrifuged at 33,000 × g. The supernatant was applied to a mannose-Sepharose 6B affinity column in the presence of calcium, and the bound protein fraction was analyzed by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis; amino acid composition was determined and partial sequencing was done. Phospholipid binding and liposome aggregation assay were performed, using purified proteins.

Results
The protein isolated by use of mannose affinity matrices was SP-D. It bound carbohydrates and phosphatidylinositol, which are the characteristic features of SP-D isolated from other animal species. Amino acid analysis and partial primary sequence of the isolated protein indicated high homology with rat and human SP-D. Furthermore, immunoblot analysis indicated that equine SP-D reacted with human and rat SP-D-specific antibodies.

Conclusion and Clinical Relevance
SP-D exists in equine lungs; its measurement may be useful in evaluating equine lung disease. (Am J Vet Res 1999;60:368–372)
Identification of serotype by use of serologic assay and detection of the enterotoxin gene of Escherichia coli by means of a polymerase chain reaction assay for isolates from pigs, chickens, and cows
Authors: Jung Hee Kon 
Published: January 2024

Abstract

Objective
To serotype an enterotoxin gene from Escherichia coli isolated from cows, pigs, and chickens in Korea.

Sample population
Isolates from 37 cows with mastitis, 51 diarrheic pigs, and 5 diarrheic chickens.

Procedure
Serogroups and serotypes were identified by slide agglutination testing, using pathogenic E coli sera. Detection of E coli enterotoxins by use of reversed passive latex agglutination and ELISA was compared by proving existence of the gene by polymerase chain reaction (PCR) analysis.

Results and Conclusions
Detection of E coli enterotoxin by either method was positive for 1 strain (O20:H10; heat-labile enterotoxin [LP+], heat-stable enterotoxin [STa+]; isolation rate, 2%) and 3 other strains (0111:H10, 0119:H9, and 0125:H6, STa+; isolation rate, 5.9%) isolated from fecal specimens obtained from diarrheic pigs. The E coli enterotoxin genes were identified by use of PCR analysis in 1 strain containing the 417- and 163-base pair (bp) genes (LT+, Sta+; O20:H10) and in 3 strains containing only the 163-bp gene (STa+; 0111:H10, 0119:H9, and 0125:H6).

Clinical Relevance
Serotyping of E coli enterotoxin may be used to analyze patterns of transmission among species of domestic animals. (Am J Vet Res 1999;60:468-472)
Systemic dexamethasone concentration in horses after continued topical treatment with an ophthalmic preparation of dexamethasone
Authors: Spiess Bernhard M. , Nyikos Sibylle , Stummer Eva , Sahin Ali , Naegeli Hanspeter 
Published: January 2024

Abstract

Objective
To determine concentrations of dexamethasone in serum and urine of horses treated repeatedly with a topically administered ophthalmic dexamethasone preparation.

Animals
4 clinically normal horses (2 mares, 2 geldings).

Procedure
0.1% dexamethasone ophthalmic ointment was administered to the left eye of each horse every 5 to 9 hours for 8 consecutive days, yielding an estimated cumulative dexamethasone dose of 6.4 μg/kg of body weight. Serum and urine samples were obtained before the first dexamethasone treatment, on days 4 and 8 of treatment, and 24, 48, and 96 hours after cessation of treatment. To detect small concentrations of dexamethasone, serum and urine samples were analyzed by use of a competitive enzyme immunoassay.

Results
During the period of continued topical treatment, serum dexamethasone concentrations increased to between 0.10 and 0.49 ng/ml, then decreased below the limit of detection (0.06 ng/ml) within 24 hours after cessation of treatment. Dexamethasone also was detected in urine samples at concentrations of up to 0.98 ng/ml.

Conclusions
Repeated topical administration of dexamethasone ophthalmic ointment generated low, but detectable glucocorticoid concentrations in serum and urine.

Clinical Relevance
Because treatment of performance horses with dexamethasone is prohibited for most types of competitions and because enhanced glucocorticoid detection methods may result in positive test results, owners and trainers may wish to reconsider entering horses in competitions during periods of treatment with ophthalmic dexamethasone preparations. (Am J Vet Res 1999;60:571–576)
Anesthesia of horses with a combination of detomidine, zolazepam, tiletamine, and isoflurane immediately after strenuous treadmill exercise
Authors: Rankin David C. , Greene Stephen A. , Keegan Robert D. , Weil Ann B. , Schneider Robert K. , Bayly Warwick M. 
Published: January 2024

Abstract

Objectives
To evaluate effects of strenuous exercise in adult horses immediately before anesthesia and to determine whether prior exercise affects anesthesia induction, recovery, or both.

Animals
6 healthy Thoroughbreds in good condition and trained to run on a treadmill, each horse serving as its own control.

Procedure
Horses ran on a treadmill until fatigued, then were sedated immediately with detomidine hydrochloride and anesthetized with a zolazepam hydrochloride-tiletamine combination. Anesthesia was maintained with isoflurane in oxygen for another 90 minutes. Blood samples were taken before, during, and after exercise and during anesthesia.

Results
During exercise, changes in heart rate, core body temperature, plasma lactate concentration, arterial pH, and PaCO2 were significant. Plasma ionized calcium concentration was lower after exercise, compared with baseline values, and remained lower at 30 minutes of isoflurane anesthesia. Compared with baseline values, plasma chloride concentration decreased significantly during anesthesia after exercise. Cardiac output during anesthesia was significantly lower than that during preexercise, but significant differences between experimental and control periods were not observed. Arterial blood pressure during anesthesia was significantly lower than that during preexercise and initially was maintained better during isoflurane anesthesia after exercise. Cardiac output and blood pressure values were clinically acceptable throughout anesthesia.

Conclusion
Administration of detomidine hydrochloride followed by zolazepam hydrochloride-tiletamine appeared to be safe and effective for sedation and anesthesia of horses that had just completed strenuous exercise.

Clinical Relevance
Anesthetic given in accordance with this protocol can be used to anesthetize horses that are injured during athletic competition to assess injuries, facilitate first aid, and possibly allow salvage of injured horses. (Am J Vet Res 1999;60:743–748)
Doppler echocardiographic study of left and right ventricular function during dobutamine stress testing in conscious healthy dogs
Authors: Entee Kathleen Mc , Clercx Cécile , Amory Hélène , Michaux Charles , Dardenne Jean-Jacques , Soyeur Daniel , Henroteaux Marc 
Published: January 2024

Abstract

Objective
To evaluate left and right ventricular filling and ejection performances by use of Doppler echocardiography in healthy, conscious dogs submitted to dobutamine stress testing.

Animals
10 unsedated, healthy adult Beagles.

Procedure
Doppler echocardiography was performed during cardiac stress testing on each dog twice at 24-hour intervals. Dobutamine was infused in 10 µg/kg of body weight/min incremental dosages, from 12.5 to 42.5 µg/kg/min. Duration of each step was 15 minutes. Doppler measurements were recorded at baseline and at each stage of dobutamine infusion, whereas aortic diameter was measured at baseline and at peak dosage by use of two-dimensional echocardiography.

Results
Dobutamine infusion induced a significant increase in velocity time integrals and in peak flow velocities at the aortic, pulmonic, mitral, and tricuspid valves. Acceleration time-to-deceleration time ratio at the aortic wave also was increased significantly. On the other hand, ejection time, acceleration time, and deceleration time at the aortic and pulmonic valves and peak flow velocity of the E wave-to-peak flow velocity of the A wave ratio at the mitral and tricuspid valves decreased significantly during the test. The acceleration time-to-deceleration time ratio at the pulmonic wave was unchanged. A significant, progressive increase in cardiac index also was observed during dobutamine infusion, with a maximal increase of 104% from baseline. This was mediated initially by an increase in stroke index and, at higher dosages, by an increase in heart rate.

Conclusions and Clinical Relevance
Doppler echocardiography performed during dobutamine stress testing may be a reliable method of assessing myocardial function in dogs with cardiovascular disease. (Am J Vet Res 1999;60:865–871)
Pharmacokinetics and therapeutic efficacy of rimantadine in horses experimentally infected with influenza virus A2
Authors: Rees William A. , Harkins J. Daniel , Lu Ming , Holland Robert E. , Lehner Andreas F. , Tobin Thomas , Chambers Thomas M. 
Published: January 2024

Abstract

Objective
To determine pharmacokinetics of single and multiple doses of rimantadine hydrochloride in horses and to evaluate prophylactic efficacy of rimantadine in influenza virus-infected horses.

Animals
5 clinically normal horses and 8 horses seronegative to influenza A.

Procedure
Horses were given rimantadine (7 mg/kg of body weight, IV, once; 15 mg/kg, PO, once; 30 mg/kg, PO, once; and 30 mg/kg, PO, q 12 h for 4 days) to determine disposition kinetics. Efficacy in induced infections was determined in horses seronegative to influenza virus A2. Rimantadine was administered (30 mg/kg, PO, q 12 h for 7 days) beginning 12 hours before challenge-exposure to the virus.

Results
Estimated mean peak plasma concentration of rimantadine after IV administration was 2.0 µg/ml, volume of distribution (mean ± SD) at steady-state (VdSS) was 7.1 ± 1.7 L/kg, plasma clearance after IV administration was 51 ± 7 ml/min/kg, and β-phase halflife was 2.0 ± 0.4 hours. Oral administration of 15 mg of rimantadine/kg yielded peak plasma concentrations of < 50 ng/ml after 3 hours; a single oral administration of 30 mg/kg yielded mean peak plasma concentrations of 500 ng/ml with mean bioavailability (F) of 25%, β-phase half-life of 2.2 ± 0.3 hours, and clearance of 340 ± 255 ml/min/kg. Multiple doses of rimantadine provided steady-state concentrations in plasma with peak and trough concentrations (mean ± SEM) of 811 ± 97 and 161 ± 12 ng/ml, respectively. Rimantadine used prophylactically for induced influenza virus A2 infection was associated with significant decreases in rectal temperature and lung sounds.

Conclusions and Clinical Relevance
Oral administration of rimantadine to horses can safely ameliorate clinical signs of influenza virus infection. (Am J Vet Med 1999:60:888–894)
Alterations in bone remodeling in the femur after medullary reaming and cemented hip arthroplasty in dogs
Authors: VanEnkevort Bruce A. , Markel Mark D. , Manley Paul A. 
Published: January 2024

Abstract

Objective
To determine whether medullary reaming alone, or followed by cemented hemiarthroplasty, influenced porosity, vascularity, and new bone formation in the proximal portion of the femur in dogs.

Animals
12 adult mixed-breed dogs.

Procedure
Unilateral femoral head and neck excisions were performed, followed by femoral medullary reaming in 6 dogs and femoral medullary reaming and cemented hemiarthroplasty in 6 dogs; the contralateral femur was used as a control. All dogs were euthanatized 28 days after surgery, and femurs were harvested. Vascularity, porosity, and new bone formation were quantified for all femurs of dogs from both groups at 3 proximal-to-distal levels, 3 regions (periosteal, midcortical, and endosteal), and 4 quadrants (cranial, caudal, medial, and lateral) of the femur.

Results
Medullary reamed and cemented hemiarthroplasty femurs had significant increases in vascularity and porosity at all levels and in new bone formation at levels 2 and 3. Porosity was increased significantly in the periosteal region of the cemented hemiarthroplasty (9.7 ± 0.7%), compared with control (2.3 ± 0.2%) and medullary reamed (8.4 ± 0.7%) femurs. Porosity was increased in the caudal and medial quadrants in the medullary reamed and cemented hemiarthroplasty femurs; vascularity results were similar.

Conclusion
Increased porosity, vascularity, and new bone formation in reamed and cemented hemiarthroplasty-treated femurs supports the theory that surgical trauma associated with medullary reaming is an important factor in early cortical bone loss after hip arthroplasty.

Clinical Relevance
Femoral remodeling associated with reaming and broaching is appreciable but may be only a temporary response, whereas other factors may be responsible for chronic cortical bone loss. (Am J Vet Res 1999;60:922–928)
Response of embryonic chicken lymphocytes to in ovo exposure to lymphotropic viruses
Authors: St. Hill Catherine A. , Sharma Jagdev M. 
Published: January 2024

Abstract

Objective
To examine effects of virus exposure on embryonic lymphoid organ structure, apoptosis, and lymphoid cell subpopulations.

Animals
Eggs of specific pathogen free (SPF) White Leghorn chickens at embryonation day (ED) 17.

Procedures
Eggs were inoculated with 2,000 plaque-forming units (PFU) of serotype 1 herpesvirus (Marek’s disease virus [MDV 1]), 2,000 PFU of herpesvirus of turkeys (MDV 3), or 1,000 embryo infectious doses (EID50) of infectious bursal disease virus (IBDV). On post-inoculation days (PID) 3 and 5, lymphoid organ to body weight ratios were determined, and bursa of Fabricius, thymus, and spleen were evaluated for lesions and apoptosis. Proportions of lymphoid cell subpopulations of PID-3 chicken embryos and 7- to 10-day-old chicks were quantitated by flow cytometry.

Results
Lymphoid organ weights were similar in virus-free, MDV 1, and IBDV groups. Embryos inoculated with 2,000 PFU MDV 3/egg had lower bursal weights than virus-free controls. In a repeated trial, MDV 3 (1,000 PFU to 4,000 PFU) did not reduce bursal weights among groups. Histologic changes were seen in bursae after MDV 1 and IBDV inoculation. Apoptosis was greater in bursae of MDV 1-infected embryos than controls. Lymphoid cell subpopulations were similar among all groups with the exception of CD8+ and IgM+ cells in spleens of IBDV-infected 10-day-old chicks.

Conclusions and Clinical Relevance
Infection with pathogenic strains of MDV 1 and IBDV did not alter lymphocyte subpopulations in embryos or cause complete destruction of lymphoid organs. Changes in lymphoid cell subpopulations exposed as embryos to IBDV were seen only after hatching. (Am J Vet Res 1999;60:937–941)