bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survival of Mycobacterium paratuberculosis and preservation of immunoglobulin G in bovine colostrum under experimental conditions simulating pasteurization
Authors: Meylan Mireille , Rings D. Michael , Shulaw William P. , Kowalski Joseph J. , Bech-Nielsen Steen , Hoffsis Glen F. 
Published: January 2024

Abstract

Objective
To determine whether Mycobacterium paratuberculosis could survive in colostrum after pasteurization. Additionally, this study investigated the effect pasteurization had on IgG concentration in colostrum.

Animals
Colostrum samples were collected from cattle (beef and dairy) owned by the state of Ohio.

Procedure
Colostrum was divided into aliquots and inoculated with variable concentrations of M paratuberculosis (ATCC No. 19698: 104, 103, and 102 colony-forming units/ml). Half the samples at each concentration were subjected to pasteurization temperatures (63 C) for 30 minutes and the remainder were kept at approximately 20 to 23 C. All samples were incubated (Herrold's egg yolk medium with and without mycobactin J) and observed for growth during the next 16 weeks. Additionally, the IgG concentration of colostrum was determined by radioimmunoassay before and after pasteurization. Samples that coagulated at pasteurization temperatures were mechanically resuspended before measurement of IgG concentration.

Results
Growth of M paratuberculosis was retarded but not eliminated by pasteurization. Growth was observed in all unpasteurized samples incubated on Herrold's egg yolk medium with mycobactin J but in only 2 of 18 pasteurized samples similarly cultured. Growth from pasteurized samples appeared 5 to 9 weeks after growth was observed from nonpasteurized samples.
Mean colostral IgG concentration was 44.4 g/L in nonpasteurized samples and 37.2 g/L in pasteurized sample, a decrease of 12.3%. High-quality colostrum (> 48 g of IgG/L) had a significantly greater loss of IgG concentration than did colostrum of lesser quality (P = 0.002).

Conclusions
Pasteurization lessened, but did not eliminate, growth of M paratuberculosis from experimentally inoculated colostrum samples. Pasteurization resulted in a significant decrease in colostral IgG concentration but not to an unmanageable level that would preclude the colostrum's use for passive transfer of immunity.

Clinical Relevance
Colostrum is macrophage rich and may serve as a source of M paratuberculosis infection to calves. Pasteurization of colostrum may lessen the risk of infection, but will not totally eliminate M paratuberculosis. (Am J Vet Res 1996;57:1580–1585)
Attempted transmission of Ehrlichia canis by Rhipicephalus sanguineus after passage in cell culture
Authors: Mathew J. S. , Ewing S. A. , Barker R. W. , Fox J. C. , Dawson J. E. , Warner C. K. , Murphy G. L. , Kocan K. M. 
Published: January 2024

Abstract

Objectives
To compare the transmissibility by the brown dog tick, Rhipicephalus sanguineus, of a recent isolate of Ehrlichia canis (Ebony) with that of another isolate (Oklahoma) that had been passaged in cell culture, and to assess the genetic similarity of the 2 isolates as reflected in the nucleotide (NT) sequence of 16S rDNA.

Animals
13 healthy dogs of various ages and breeds.

Procedure
Larval and nymphal ticks were acquisition fed on acutely infected dogs, and, after molting, they were transmission fed as nymphs and adults, respectively, on Ehrlichia-naive dogs. All dogs were monitored daily by blood smear evaluation for evidence of parasitized leukocytes and by physical examination for clinical signs of ehrlichiosis. Serologic and hematologic values were measured weekly. Using a nested polymerase chain reaction, the 16S rDNA was amplified, and the NT sequence of the template DNA was determined.

Results
The Ebony isolate of E canis was successfully transmitted to dogs by nymphal and adult ticks. In contrast, no ticks that fed on dogs harboring the cell-cultured isolate (Oklahoma) transmitted it to dogs. On the basis of 16S rDNA sequence, the 2 isolates were 99.9% similar, with only 1 NT difference.

Conclusions
These results reconfirm the vector potential of R sanguineus for E canis. Passage of the Oklahoma isolate of E canis in cell culture apparently adversely affected its transmissibility by ticks, raising the possibility that cell-cultured isolates of this rickettsia may lose their affinity for ticks. Determination of 16S rDNA sequence suggests minor strain variation within the species E canis. (Am J Vet Res 1996;57:1594–1598)
Abortion and placentitis in pregnant bison (Bison bison) induced by the vaccine candidate, Brucella abortus strain RB51
Authors: Palmer Mitchell V. , Olsen Steven C. , Gilsdorf Michael J. , Philo Lee M. , Clarke Patrick R. , Cheville Norman F. 
Published: January 2024

Abstract

Objective
To determine the ability of Brucella abortus strain RB51 to induce placentitis and abortion in bison after SC vaccination.

Animals
10 pregnant bison cows, 3 to 10 years old and at 3 to 8 months' gestation.

Procedure
Pregnant bison cows on a Montana ranch were vaccinated SC with 109 colony-forming units of B abortus strain RB51. Two cows, identified prior to the study, were euthanatized and examined 5 weeks after vaccination to obtain optimal histologic samples of placenta. Other cows were euthanatized and examined after abortion. After euthanasia, tissue specimens were collected for histologic and immunohistochemical evaluation. Tissue and fluid specimens for bacteriologic culture were also collected during necropsy.

Results
Of 8 cows, 2 aborted at 68 and 107 days after vaccination. Aborting cows had endometritis. Strain RB51 was isolated from reproductive tissues and supramammary lymph nodes. Fetal lesions were not seen; however, fetal bronchial lymph nodes and amniotic fluid contained strain RB51. Cows examined 5 weeks after vaccination had placentitis and endometritis, with numerous bacteria within trophoblastic epithelial cells that were immunoreactive for strain RB51 antigen. Strain RB51 was isolated from placentomes and numerous lymph nodes. Fetal lesions were not seen 5 weeks after vaccination; however, strain RB51 was isolated from numerous lymph nodes and lung, allantoic fluid, and rectal swab specimens.

Conclusions
The vaccine candidate B abortus RB51 has tropism for the bison placenta, and can cause placentitis, which induces abortion in pregnant bison. The vaccine dose used was similar to that being tested in cattle, but may not be appropriate for pregnant bison. (Am J Vet Res 1996;57:1604–1607)
Effects of naturally acquired decompensated mitral valve regurgitation on the renin-angiotensin-aldosterone system and atrial natriuretic peptide concentration in dogs
Authors: Häggström Jens , Hansson Kerstin , Kvart Clarence , Karlberg Bengt E. , Vuolteenaho Olli , Olsson Kerstin 
Published: January 2024

Abstract

Objective
To investigate activity of the renin-angiotensin-aldosterone system and N-terminal pro-atrial natriuretic peptide (NT-proANP) during development of clinical signs of decompensated mitral valve regurgitation (MR).

Animals
11 Cavalier King Charles Spaniels with advanced MR attributable to chronic valvular disease.

Procedure
Dogs were subjected to repeated examinations at 6-month intervals until signs of decompensation had developed (end point). Data acquired at end point were compared with data obtained from examinations 1 year and 1 to 6 months before decompensation. Each examination included physical examination, collection of venous blood, thoracic radiography, and echocardiography.

Results
Echocardiography measurements of left atrial-to-aortic root ratio and left ventricular end diastolic diameter increased considerably during the study, whereas left ventricular end systolic diameter remained unchanged. The increase in cardiac size was associated with increased plasma concentration of NT-proANP. In contrast, plasma concentrations of aldosterone and angiotensin II were reduced at decompensation (aldosterone compared with the 2 earlier examinations and angiotensin II compared with values obtained 1 to 6 months before), despite decreased plasma protein concentration and hematocrit, suggesting fluid retention. The urine-to-plasma creatinine ratio was reduced at end point.

Conclusion and Clinical Implications
Early decompensated MR in dogs was not associated with increased circulating renin-angiotensin-aldosterone system activity, which may be caused by increased activity of ANP, and may be important for future therapeutic strategies of MR. (Am J Vet Res 1997;58:77–82)
Optimization of prothrombin time measurements in canine plasma
Authors: Mischke Reinhard , Nolte Ingo 
Published: January 2024

Abstract

Objective
To optimize a prothrombin time (PT) method designed for human plasma for use with canine plasma.

Sample Population
100 plasma samples from healthy dogs and 50 plasma samples with reduced activity of the single factors II, V, VII or X.

Procedure
Canine plasma samples with various coagulation activity values (100, 75, 50, 25 and 10%: prepared by dilution from a plasma pool [n = 100]) were assayed at various sample dilutions and dilutions of the thromboplastin component of 3 commercial calcium thromboplastin reagents. The so-named optimized PT test was compared with the standard test with respect to its sensitivity and correlation with the sum of the activity decreases of single factors II, V, VII, and X in relation to the respective reference range.

Results
The time intervals between various coagulation activity values, which were small by use of the standard test, could be increased by diluting the sample and substituting fibrinogen, but not by diluting the tissue thromboplastin component of PT reagent. On the basis of 50 abnormal plasma samples, the optimized test had high sensitivity (0.90 to 1.00, dependent on reagent and sample dilution) in contrast to the standard test, which had low sensitivity (0.24 to 0.58, dependent on reagent). Also, correlation with the sum of the activity decreases was closer by use of the optimized (0.90 to 0.93) than the standard (0.58 to 0.84) test.

Conclusions
In contrast to the standard test, an optimized test is suitable as a sensitive screening test of the extrinsic coagulation system in dogs.

Clinical Relevance
The optimized PT method is easy to perform and, therefore, should be in general use for assay of canine plasma. (Am J Vet Res 1997; 58:236–241)
Stability of γ-glutamyltransferase activity in calf sera after refrigerated or frozen storage
Authors: Muller Fred , Tyler Jeff W. , Parish Steven M. , Johnson Kristen A. , Krytenberg Denise S. , Wilson Leilani K. 
Published: January 2024

Abstract

Objectives
To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves.

Animals
10 commercial beef calves between 36 and 60 hours old.

Procedure
Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (−20 C).

Results
Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity.

Conclusion
The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity. (Am J Vet Res 1997;58:354-355)
Effects of thermal environment on response to acute peripheral lipopolysaccharide challenge exposure in neonatal pigs
Authors: Klir John J. , Shahbazian L. Masoud , Matteri Robert L. , Fritsche Kevin L. , Becker B. Ann 
Published: January 2024

Abstract

Objective
To evaluate effects of thermal environment on response to acute peripheral lipopolysaccharide (LPS) challenge exposure in neonatal pigs.

Animals
26 neonatal pigs.

Procedure
Pigs were assigned to the following treatment groups: 1 warm environment/LPS; 2 warm environment/saline solution; 3 cool environment/LPS; and 4 cool environment/saline solution. For each pig given LPS. 1 littermate of the same sex was given saline solution. Sows with baby pigs were housed in a warm (32 C) or cool (21 C) thermal environment. At 28 days of age, pigs were given 150 µg/kg of body weight of Escherichia coli LPS or saline solution intraperitoneally as a control. Rectal temperature and signs of sickness were monitored for 3 hours after LPS administration, when pigs were euthanatized and blood samples were collected to determine serum concentrations of tumor necrosis factor (TNF) α and cortisol. To determine in vitro production of TNFα, alveolar macrophages were collected by tracheal lavage and incubated for 24 hours at 37 or 41 C, with or without LPS (10 µg/ml).

Results
Thermal environment had a significant (P = 0.0004) effect on rectal temperature; LPS administration induced a febrile response (P = 0.0007) only in pigs in the warm environment. All LPS-injected pigs developed signs of endotoxemia; serum TNFα and cortisol concentrations were significantly increased (TNFα, P = 0.003; cortisol, P = 0.0001); there was no significant in vivo thermal effect on serum TNFα and cortisol concentrations. LPS-stimulated alveolar macrophages produced significantly less (P = 0.0086) TNFα when incubated at 41 C.

Conclusions
Thermal environment can have a significant impact on the response of neonatal pigs exposed to bacterial endotoxins. (Am J Vet Res 1997; 58:364-369)
Evaluation of arginine-glycine-aspartate-containing peptides as inhibitors of equine platelet function
Authors: Weiss Douglas J. , Evanson Oral A. , Wells Roger E. 
Published: January 2024

Abstract

Objectives
To determine whether synthetic peptides containing the arginine-glycine-aspartate (RGD) sequence inhibit equine platelet function.

Animals
For in vitro studies of blood, 3 healthy Thoroughbreds; for in vivo and ex vivo studies of administration of RGD-containing peptides, 4 young adult pony mares.

Procedure
Blood was incubated with and without addition of aspirin or RGD-containing peptides (RGDS, RPR 110885) and platelet aggregation responses and platelet adhesion to subendothelial collagen were determined. RPR 110885 was administered IV, and platelet function was evaluated. Platelet aggregation was determined by a turbidimetric method, and platelet adhesion was evaluated by the Baumgartner perfusion method. RPR110885 was administered IV at dosages of 30 and 60 μg/kg of body weight, and bleeding time, platelet aggregation responses, and platelet count were determined at hourly intervals for 4 hours.

Results
Both RGDS and RPR 110885 inhibited platelet aggregation in vitro in dose-dependent manner and inhibited platelet adhesion to subendothelial collagen. The concentration of RGDS that inhibited platelet aggregation by 50% (IC50) was 100 to 142 μM for the various agonists tested, whereas the concentration of RPR 110885 that inhibited platelet aggregation by 50% was 0.03 to 0.05 μM. When administered to ponies at 30 or 60 g/kg, RPR 110885 almost completely inhibited ADP-induced platelet aggregation.

Conclusions
RGDS and RPR 110885 inhibited equine platelet function; however, RPR 110885 was several thousand times more potent than RGDS.

Clinical Relevance
RGD-containing peptides may be useful for treatment of thrombotic diseases of horses. (Am J Vet Res 1997;58:457–460)
Temporal effects of an infusion of dopexamine hydrochloride in horses anesthetized with halothane
Authors: Young L. E. , Blissitt K. J. , Clutton R. E. , Molony V. 
Published: January 2024

Abstract

Objective
To evaluate the hemodynamic effects of a 60-minute infusion of dopexamine in horses anesthetized with halothane.

Animals
7 adult Thoroughbreds.

Procedure
Measurements of left ventricular function obtained by transesophageal Doppler echocardiography and cardiac catheterization.

Results
Infusion of dopexamine (4 μg/kg of body weight/min) significantly increased heart rate, cardiac output, maximal rates of increase and decrease of left ventricular pressure, and maximal acceleration and maximal velocity of aortic blood flow. Left ventricular ejection time significantly increased, and pre-ejection period decreased during the infusion. Cardiac output, maximal rate of increase of left ventricular pressure, and maximal acceleration continued to increase as the infusion progressed. Right ventricular end-diastolic pressure was significantly decreased after 20 minutes of infusion and decreased progressively throughout the remaining time of infusion. Many hemodynamic variables, including right ventricular end-diastolic pressure, had not returned to control values 30 minutes after the infusion was discontinued. A number of undesirable adverse effects were observed in horses receiving dopexamine infusion; during administration, profuse sweating occurred in every horse. In 6 horses, recovery from anesthesia was associated with excitement and violent shivering. Colic developed in 2 horses within 3 hours of recovery.

Conclusions
Dopexamine (4 μg/kg/min) does not achieve a peak effect on many hemodynamic variables within a short period of commencing administration, and the effects of infusion may persist for extended periods after drug administration is discontinued.

Clinical Relevance
Dopexamine has a hemodynamic profile suited to treatment of low cardiac output in anesthetized horses; however, at the dosage rate studied (4 μg/kg/min), its administration was associated with a number of undesirable adverse effects which could preclude its clinical use. (Am J Vet Res 1997;58:516–523)
Muscarinic hyperresponsiveness of antigen-sensitized feline airway smooth muscle in vitro
Authors: Mitchell R. W. , Ndukwu I. M. , Leff A. R. , Padrid P. A. 
Published: January 2024

Abstract

Objective
To determine the effect of in vivo antigen sensitization (Ascaris suum) of cats on tracheal smooth muscle (TSM) and bronchial smooth muscle (BSM) muscarinic reactivity in vitro.

Animals
Healthy domestic shorthair cats of either sex.

Procedure
Cats were sensitized and were longterm antigen (or sham) challenge exposed for 6 weeks by aerosolization with soluble Ascaris suum. Tracheal and BSM preparations were obtained and stimulated in vitro by electrical field stimulation (EFS), acetylcholine (ACh, a muscarinic agonist), and physostigmine (an AChase inhibitor). Responses were compared with responses of comparable tissues from sham antigen challenge-exposed cats.

Results
Tracheal and BSM from sensitized, compared with sham-sensitized (control), cats had greater isometric contraction (expressed as percentage of the response observed for isotonic, 63 mM KCl-elicited contraction [% KCI]) in response to endogenous (EFS) and exogenous muscarinic receptor activation (ACh). Contractions in response to EFS by TSM from control cats were 74 % KCI vs 97 %KCI for antigen-sensitized TSM (P < 0.04). Muscarinic responses were augmented comparably by in vivo sensitization; TSM from control cats contracted to 190 % KCI vs 230 % KCl (P < 0.03) for TSM from immune-sensitized cats. Physostigmine augmented responses of all tissues to ACh so that TSM from control (290 %KCI) and antigen-sensitized (257 %KCI) cats were similar. Responses of BSM from antigen-sensitized cats had similar augmentation of contractile response to EFS and ACh.

Conclusions
Long-term in vivo antigen sensitization increases numbers of muscarinic receptors on airway smooth muscle or decreases the availability or activity of AChase in cats.

Clinical Relevance
Modulation of muscarinic receptors may be useful for treatment of asthmatic cats with in vivo airway hyperreactivity. (Am J Vet Res 1997;58:672–676)
Endocrine changes in cerebrospinal fluid, pituitary effluent, and peripheral plasma of anesthetized ponies
Authors: Luna Stelio P. L. , Taylor Polly M. , Bloomfield Malcolm 
Published: January 2024

Abstract

Objective
To investigate the effects of inhalation and total IV anesthesia on pituitary-adrenal activity in ponies.

Animals
9 healthy ponies: 5 geldings and 4 mares.

Procedure
Catheters were placed in the cavernous sinus below the pituitary gland and in the subarachnoid space via the lumbosacral space. After 72 hours, administration of acepromazine was followed by induction of anesthesia with thiopentone and maintenance with halothane (halothane protocol), or for the IV protocol, anesthesia induction with detomidine and ketamine was followed by maintenance with IV infusion of a detomidine-ketamine-guaifenesin combination. Arterial blood pressure and gas tensions were measured throughout anesthesia. Peptide and catecholamine concentrations were measured in pituitary effluent, peripheral plasma, and CSF. Peripheral plasma cortisol, glucose, and lactate concentrations also were measured.

Results
Intravenous anesthesia caused less cardiorespiratory depression than did halothane. ACTH, metenkephalin, arginine vasopressin, and norepinephrine pituitary effluent and peripheral plasma concentrations were higher during halothane anesthesia, with little change during intravenous anesthesia. Pituitary effluent plasma β-endorphin and peripheral plasma cortisol concentrations increased during halothane anesthesia only. Dynorphin concentrations did not change in either group. Hyperglycemia developed during intravenous anesthesia only. Minimal changes occurred in CSF hormonal concentrations during anesthesia.

Conclusion
The pituitary gland has a major role in maintaining circulating peptides during anesthesia. Compared with halothane, IV anesthesia appeared to suppress pituitary secretion. (Am J Vet Res 1997;58:765–770)
Vitreous body glutamate concentration in dogs with glaucoma
Authors: Brooks D. E. , Garcia G. A. , Dreyer E. B. , Zurakowski D. , Franco-Bourland R. E. 
Published: January 2024

Abstract

Objective
To analyze the vitreal amino acid concentrations in dogs with breed-related primary glaucoma to determine whether excitotoxic amino acids associated with retinal ganglion cell death in other species were present in affected dogs.

Samples
11 normal control and 10 glaucomatous canine eyes.

Procedure
Amino acid analyses were performed by high-pressure liquid chromatography in masked manner.

Results
Eyes from dogs with primary glaucoma had significantly high vitreal glutamate concentration, compared with values for eyes of clinically normal control dogs. Mean (± SD) glutamate concentrations were 31.7 ± 12.4 and 6.9 ± 6.3 μM in glaucomatous and normal eyes, respectively (P < 0.0001). Eyes from dogs with glaucoma also had lower vitreal glycine (37.0 ± 17.0 vs 59.4 ± 28.2 μM; P < 0.043) and higher of vitreal tryptophan (39.0 ± 22.8 vs 17.5 ± 11.2 μM; P < 0.012) concentrations, compared with values for normal eyes.

Conclusion
Glutamate concentration potentially toxic to retinal ganglion cells is associated with the pathogenesis of primary glaucoma in dogs. Increased glutamate concentration provides evidence of an ischemic mechanism for retinal ganglion cell death and optic nerve atrophy in dogs with glaucoma.

Clinical Relevance
The emphasis on reduction and normalization of high intraocular pressure as the primary focus of treatment for glaucoma in dogs should be augmented by other therapeutic approaches. (Am J Vet Res 1997;58:864–867)