bluuebunny/crossref_metadata_2025_split huggingface dataset:
Myocarditis in mice and guinea pigs experimentally infected with a canine-origin Borrelia isolate from Florida
Authors: Breitschwerdt Edward B. , Geoly Frank J. , Meuten Donald J. , Levine Jay F. , Howard Peter , Hegarty Barbara C. , Stafford Laurie C. 
Published: January 2024

Abstract

Objective
To characterize the pathogenic potential of a unique Borrelia isolate obtained from a dog from Florida (FCB isolate).

Design
Prospective experimental infection.

Animals
32 preweanling Swiss Webster mice and 12 adult male Hartley guinea pigs were injected intraperitoneally with 105 spirochetes.

Procedure
Mice were used as controls and blood recipients, and at 3- to 4-day intervals, 1 control mouse and 2 infected mice were necropsied, tissues were cultured, and a recipient mouse was inoculated with blood. Guinea pigs were randomized to 4 groups and inoculated intradermally with 100, 102, 103, or 104 spirochetes. For 48 days, clinical, hematologic, serologic, and microbiologic tests were performed on them, after which they were necropsied.

Results
In mice, spirochetemia was detectable between postinoculation days (PID) 3 and 13, and seroreactivity to homologous antigen was detectable during PID 10 through 31. Compared with control mice, infected mouse spleens were 2 to 3 times larger. Histologic lesions included lymphoid hyperplasia, neutrophilic panniculitis, epicarditis, and myocarditis, with intralesional spirochetes detected from PID 3 through 6. During PID 10 through 31, nonsuppurative epicarditis developed. Signs of illness and hematologic abnormalities were not observed in guinea pigs, despite isolating spirochetes from blood during PID 7 to 27. When necropsied on PID 48, histologic lesions included lymphoid hyperplasia and lymphocytic plasmacytic epicarditis.

Conclusions
The FCB isolate causes spirochetemia, lymphoid hyperplasia, dermatitis, and myocardial injury in Swiss Webster mice and can be transmitted by blood inoculation. In Hartley guinea pigs, the isolate causes spirochetemia, lymphoid hyperplasia, and epicarditis. Documentation of disease in mice, guinea pigs, and, presumably, dogs raises the level of concern that the FCB isolate might be pathogenic for man and other animal species. (Am J Vet Res 1996;57:505–511)
Effect of pertussis toxin and B-oligomer on platelet-activating factor-induced generation of inositol phosphates in porcine alveolar macrophages
Authors: Dodam John Richard , Adler Kenneth Bruce , Olson Neil Chester 
Published: January 2024

Abstract

Objective
To test the hypothesis that platelet-activating factor (PAF) induces inositol phosphate turnover through a receptor-linked, pertussis toxin-sensitive guanine nucleotide-binding (G) protein-dependent pathway in porcine alveolar macrophages.

Design
Randomized complete block design was used with 2 or 3 replicates/block.

Animals
Porcine alveolar macrophages were obtained by lavage of excised lungs from Yorkshire-type pigs (mean ± SEM, 21 ± 2 kg).

Procedure
Phospholipase C activation was assessed, using anion exchange chromatography to measure accumulation of inositol phosphates in [3H)myo-inositol-labeled alveolar macrophages. Macrophages were incubated with saline solution, pertussis toxin (4.75 nM), or B-oligomer (4.75 nM) for 2 hours. Cells then were washed and incubated for 5 minutes with PAF (0, 0.1, 1.0, or 10 μM; n = 15). Results were expressed as total inositol phosphates (inositol monophosphate, bisphosphate, trisphosphate, and tetrakisphosphate).

Results
Concentrations of total inositol phosphates were significantly (P < 0.05) increased to 162 ± 7, 172 ± 4, and 194 ± 9% of control in response to 0.1, 1.0, and 10 μM PAF, respectively. Pertussis toxin attenuated the PAF-induced increase in total inositol phosphates by approximately 50% (P < 0.05). The B-oligomer of pertussis toxin failed to modify PAF-induced increases in total inositol phosphates. The specific PAF receptor antagonist WEB 2086 markedly attenuated PAF-induced (10 μM) increase in inositol phosphates.

Conclusions
We conclude that PAF stimulates accumulation of inositol phosphates through a specific receptor and that a pertussis toxin-sensitive G protein is involved in the signal transduction process leading to activation of phospholipase C in porcine alveolar macrophages. (Am J Vet Res 1996;57:574-579)
Surgical creation of portacaval shunts during temporary intestinal arterial and venous occlusion in dogs
Authors: Allen S. W. , Laflamme D. P. , Huber T. L. , Prasse K. W. 
Published: January 2024

Abstract

Objective
To surgically create complete portacaval shunts in dogs during temporary arrest of intestinal arterial and portal venous blood flow.

Design
Complete portacaval anastomoses were surgically created, and liver function was evaluated for 14 to 18 weeks after surgery.

Animals
32 adult mixed-breed dogs of either sex.

Procedure
Administration of deferoxamine and temporary intestinal arterial occlusion were used to minimize the intestinal cellular damage resulting from the complete, temporary arrest of portal venous blood flow during creation of the portacaval anastomosis. Side-to-side, appositional anastomoses (> 2 cm diameter) were formed between the portal vein and caudal vena cava. Dogs were observed daily for signs of hepatic encephalopathy, and food intake was recorded. Body weight was recorded weekly. Preprandial plasma ammonia, serum urea nitrogen, and glucose concentrations and sulfobromophthalein retention were measured monthly. The dogs were euthanatized, and necropsy was performed 14 to 18 weeks after surgery.

Results
30 of 32 dogs recovered without complications. Complete portosystemic shunting was documented by increased plasma ammonia concentration, decreased serum urea nitrogen and glucose concentrations, prolonged sulfobromophthalein retention (P < 0.01), and inspection at necropsy.

Conclusion
This method of providing temporary, complete arrest of portal venous blood flow was helpful in allowing accurate, appositional portacaval anastomoses to be created that remained patent for 14 to 18 weeks.

Clinical Relevance
This method of providing temporary, complete arrest of portal venous blood flow may prove useful in clinical surgery when temporary arrest of portal blood flow is desired. (Am J Vet Res 1996;57:588-591)
Event-time analysis of the effect of season of parturition, parity, and concurrent disease on parturition-to-conception interval in dairy cows
Authors: Harman J. L. , Gröhn Y. T. , Erb H. N. , Casella G. 
Published: January 2024

Abstract

Objective
To quantify the effect of season of parturition, parity, and various diseases on time to conception.

Design
Event-time analysis (survival analysis).

Sample Population
44,450 cows delivering calves between September 1985 and September 1986, from 6,227 Ayrshire dairy herds in 80 Finnish communities.

Procedure
Primiparous and multiparous cows were analyzed in separate Cox proportional hazards models for postpartum days 56 to 120. Occurrence of 43 diseases or disorders was recorded; codes were condensed into 25 variables offered to each model. Season of parturition was categorized into spring, summer, and fall-winter; for multiparous cows, 3 categorical variables represented parity. Models controlled for 60-day milk and milk fat production, herd milk production, and community. For all observations, parturition-to-conception interval was plotted against calendar day of parturition.

Results
For multiparous cows, parturition in the spring or summer and being of parity 2 or 3-4 (vs older) increased the chance of conceiving; 10 diseases or disorders decreased this probability. Similarly, in the model for primiparae, parturition in spring or summer increased the probability of conception, and 6 disorders decreased it. Disorders that were detrimental in both models were anestrus, ovulatory dysfunction, other infertility, late metritis, and clinical ketosis.

Conclusions
The effect of season on the parturition- to-conception interval was marked at this latitude. Parturition during late April, causing confluence of postpartum day 55 with the summer solstice, was associated with the shortest parturition-to-conception intervals. Ketosis was found to be an important factor in lengthening the parturition-to-conception interval, highlighting the effect of negative energy balance on postpartum restoration of reproductive function. (Am J Vet Res 1996; 57:640–645)
Pharmacokinetics of diminazene in plasma and lymph of goats
Authors: Mamman Mohammed , McKeever Declan J. , Aliu Yusuf O. , Peregrine Andrew S. 
Published: January 2024

Abstract

Objective
To characterize the pharmacokinetics of diminazene in plasma and pseudo-afferent lymph of East Africa × Galla goats.

Design
The efferent prescapular lymphatic duct of 3 goats was cannulated 8 weeks after surgical removal of the lymph node. Thereafter, 3.5 mg of diminazene base/ kg of body weight was administered to these goats and to 3 noncannulated goats.

Procedure
Using high-performance liquid chromatography, concentration of diminazene was determined in plasma and lymph collected up to 96 hours after treatment.

Results
Maximal concentrations of diminazene in plasma of noncannulated goats (median [range], 4.30 [4.28 to 5.01] μg/ml), plasma of cannulated goats (3.94 [2.94 to 4.06] μg/ml), and lymph (1 06 [0.73 to 1.86] μg/ ml) were significantly different (P <0.05); values in lymph were considerably lower than those in plasma from noncannulated and cannulated animals. Time to reach maximal concentration did not differ significantly between lymph and plasma of noncannulated and cannulated goats. Over the first 24 hours after drug administration, concentration of diminazene in plasma of noncannulated goats was generally higher than that in lymph, but thereafter was similar. Apparent volume of distribution of diminazene in the plasma of noncannulated (2.57 [1.93 to 2.60] L/kg) and cannulated (2.30 [1.04 to 2.40] L/kg) goats did not differ significantly. Penetration ratio of diminazene into lymph, compared with plasma, of cannulated goats was 1.69:1.

Conclusions
Disposition of diminazene in goats is characterized by higher concentration in plasma than in lymph. However, the drug persists longer in lymph than in plasma.

Clinical Relevance
The longer persistence of diminazene in lymph than in plasma may account for the enhanced therapeutic efficacy of diminazene in the early stage, compared with later stages, of a tsetse fly-transmitted trypanosome infection. (Am J Vet Res 1996; 57:710–714)
Cardiovascular response to exogenous serotonin in healthy calves
Authors: Linden Annick S. , Desmecht Daniel J. M. , Amory Hélène , Beduin Jean-Marie , Lekeux Pierre M. 
Published: January 2024

Abstract

Objective
To characterize the cardiovascular response to IV administration of serotonin (5-hydroxytryptamme [5- HT]) in calves.

Animals
5 healthy unsedated Friesian calves.

Procedure
41 5-HT administrations were performed: 11 slow infusions (duration, 5 minutes) and 30 bolus infusions (duration, 5 seconds). Cardiovascular function values were recorded before, during, and after the infusions.

Results
Slow infusion of 5-HT first resulted in a brief period of severe bradycardia, then in sustained tachycardia with a concomitant increase in cardiac output. Systemic blood pressure response to 5-HT was triphasic, with initial hypotension concomitant with bradycardia, then a pressor phase associated with an increase in systemic vascular resistance, and finally, a long-lasting hypotensive phase associated with decreased systemic vascular resistance. Pulmonary hypertension was associated with increased pulmonary vascular resistance, reflecting intense pulmonary vasoconstriction. Bolus infusion at increasing dosages resulted in dose-dependent bradycardia and systemic hypotension, followed by dose-dependent systemic hypertension. Unlike with slow infusion, neither the second tachycardic nor the third systemic hypotensive phases were evident.

Conclusions
5-HT induces dose-dependent cardiovascular responses, including a reflex response followed by pulmonary and systemic vasoconstriction, in healthy calves.

Clinical Relevance
Determining the type of serotonergic receptors responsible for these responses may help to determine whether 5-HT is involved in the mechanisms underlying brisket disease in cattle. (Am J Vet Res 1996; 57:731–738)
Mitral valve protrusion assessed by use of B-mode echocardiography in dogs with mitral regurgitation
Authors: Nakayama Tomohiro , Wakao Yoshito , Nemoto Hirofumi , Uechi Masami , Kageyama Toshiaki , Muto Makoto , Takahashi Mitsugi 
Published: January 2024

Abstract

Objective
To examine our hypothesis that changes of the mitral valve in dogs with mitral regurgitation lead to various degrees of protrusion of the cusp in individual dogs in systole.

Design
Assessing the mitral protrusion, using B-mode echocardiography in dogs with mitral regurgitation.

Animals
33 dogs with chronic mitral regurgitation and 40 clinically normal dogs.

Procedure
The mitral valve was imaged in the right parasternal left ventricular long-axis view, and we measured the height (H) from the coaptation point or tip of the protruded cusp to the mitral annular plane. When the tip of the protruded cusp was located beyond the mitral annular plane extending into the left atrium, H was expressed as negative values.

Results
The H in clinically normal dogs was 3.7 ± 0.8 mm. In dogs with mitral regurgitation, the mitral cusp protruded toward the left atrium to various degrees, and H was −0.7 ± 1.9 mm (range, 2.9 to −5.0 mm). The 2 dogs in the latter group with the lowest H (−5.0 and −4.5 mm, respectively) presented typical mitral flail on B-mode images. The indices of left atrial and ventricular dimension (left atrial dimension/aortic dimension and left ventricular end-diastolic dimension/body weight, respectively) were significantly higher than those in the clinically normal dogs and were negatively correlated with H.

Conclusion
The mitral valve in individual dogs with mitral regurgitation has different degrees of protrusion. The degree of protrusion might be related to the hemodynamic condition in mitral regurgitation. (Am J Vet Res 1996;57:791–797)
Effect of Pasteurella multocida toxin on physeal growth in young pigs
Authors: Ackermann Mark R. , Register Karen B. , Stabel Judith R. , Gwaltney Sharon M. , Howe Tricia S. , Rimler Richard B. 
Published: January 2024

Abstract

Objective
To determine whether Pasteurella multocida toxin (PMT) affects growth of the proximal portion of the humerus of young pigs.

Animals
20 colostrum-deprived, cesarean-derived pigs.

Design and Procedure
5 groups (n = 4/group) of pigs were formed. Group-1 pigs received 0.1 ml of phosphate-buffered saline solution for 4 weeks; group-2 pigs received 0.05 μg of PMT/kg of body weight at 14 and 21 days; group-3 pigs received 0.05 μg of PMT/kg at 28 and 35 days; group-4 pigs received 0.1 μg of PMT/kg at 14 and 21 days; and group-5 pigs received hyperimmune serum (from a sow given purified toxin) on days 13, 20, 27, and 34, and 0.1 μg of PMT/kg on days 14, 21, 28, and 35.

Results
All pigs given 0.1 μg of PMT/kg without serum died or were euthanatized, as were 4 pigs given 0.05 μg of PMT/kg. These pigs had increased serum interleukin 1 and 6 bioactivities. Pigs surviving 0.05 μg of PMT had decreased weight gain, rough coat, marked atrophy of the ventral concha (as determined by turbinate perimeter ratios), and small stature. The surviving pigs also had reduced area and decreased proliferation indices in physeal chondrocytes on the basis of bromodeoxyuridine immunoreactivity. Control and serum-treated pigs gained weight, had no clinical effects, had similar physeal areas, and had higher cell proliferation indices.

Conclusions
PMT inhibits endochondral bone formation by reducing physeal area and chondrocyte proliferation in vivo. Hyperimmune serum neutralizes the effects of toxin on weight gain, clinical appearance, physeal area, and chondrocyte proliferation.

Clinical Relevance
PMT may affect growth of the skeletal system. Antiserum to PMT is protective. (Am J Vet Res 1996;57:848–852)
Comparative efficacy of topically applied flurbiprofen, diclofenac, tolmetin, and suprofen for the treatment of experimentally induced blood-aqueous barrier disruption in dogs
Authors: Ward Daniel A. 
Published: January 2024

Abstract

Objective
To compare the relative efficacies of 4 topical nonsteroidal anti-inflammatory drugs at preventing blood-aqueous barrier (BAB) disruption in dogs.

Design
1 eye of each dog was treated with 1 % suspensions of diclofenac, flurbiprofen, suprofen, or tolmetin, or with control solution. After 4 applications of eyedrops at 10-minute intervals, BAB disruption was induced in the treated eye by anterior chamber paracentesis. The severity of BAB disruption was measured by anterior chamber fluorophotometry.

Animals
40 ocular-normal dogs.

Procedure
After pretreatment with eyedrops, rapid, 100-μl nonleaking anterior chamber paracentesis was performed in 1 eye of each dog to induce BAB disruption. 1 day after paracentesis, 1 ml of 10% fluorescein sodium was injected IV. The amount of fluorescein entering the anterior chamber of each eye was measured 30 to 60 minutes later by use of a computerized scanning fluorophotometer. The degree of BAB disruption was determined by comparing the amount of fluorescein entering the aqueous humor of the paracentesed eye with that of the nonparacentesed eye.

Results
At postparacentesis day 1, the order of statistically significant BAB-stabilizing efficacy among groups was: diclofenac > flurbiprofen > suprofen > tolmetin = control solution.

Conclusions
Topically applied 1% suspensions of diclofenac, flurbiprofen, and suprofen are effective at preventing BAB disruption after paracentesis in dogs, indicating their potential usefulness for treatment of prostaglandm-mediated ocular disease. 1 % tolmetin is no more effective than control solution. (Am J Vet Res 1996;57:875–878)
Horseshoe characteristics as possible risk factors for fatal musculoskeletal injury of Thoroughbred racehorses
Authors: Kane Albert J. , Stover Susan M. , Gardner Ian A. , Case James T. , Johnson Bill J. , Read Deryck H. , Ardans Alex A. 
Published: January 2024

Abstract

Objective
To evaluate selected shoe characteristics as risk factors for fatal musculoskeletal injury (FMI) and specifically for suspensory apparatus failure (SAF) and cannon bone condylar fracture (CDY) of Thoroughbred racehorses in California.

Design
Case-control study.

Animals
Thoroughbred racehorses (n = 201) that died or were euthanatized at California racetracks between August 1992 and July 1994.

Procedure
Shoe characteristics were compared between case horses affected by FMI (155), SAF (79), and CDY (41) and control horses that died for reasons unrelated to the appendicular musculoskeletal system (non-FMI; 46). Multivariable logistic regression was used to estimate odds ratios for FMI, SAF, and CDY.

Results
Toe grabs were identified as possible risk factors for FMI, SAF, and CDY. The odds of FMI, SAF, and CDY were 1.8, 6.5, and 7.0, respectively, times greater for horses shod with low toe grabs than for horses shod without toe grabs on front shoes. Horses shod with regular toe grabs on front shoes had odds 3.5, 15.6, and 17.1 times greater (P < 0.05) for FMI, SAF, and CDY, respectively, compared with horses shod without toe grabs. The odds of horses shod with rim shoes were a third (P < 0.05) of those shod without rim shoes for either FMI or SAF. The apparent association between toe grab type and CDY may, in part, be attributable to concurrent SAF and CDY injuries in many horses.

Clinical Relevance
Avoiding the use of toe grabs should decrease the incidence of FMI, especially SAF, in Thoroughbred racehorses. The use of rim shoes that are more consistent with natural hoof shape may decrease injury risk. (Am J Vet Res 1996;57:1147-1152)
Pulmonary function measurements during repeated environmental challenge of horses with recurrent airway obstruction (heaves)
Authors: Tesarowski David B. , Viel Laurent , McDonell Wayne N. 
Published: January 2024

Abstract

Objectives
To evaluate the degree of reproducibility in clinical variables, blood gas measurements, and lung function variables, and the changes in these variables caused by exposure to moldy hay in naturally sensitized and control horses.

Procedure
The magnitude of variation in arterial blood gas and pulmonary function measurements were evaluated in a model of naturally acquired heaves. Horses with heaves and similarly aged control horses were studied prior to moldy hay challenge and again after the horses with heaves manifested clinical signs of airway obstruction. This cycle of testing was repeated 3 times to determine the variation of the before and after challenge measurements. Variables evaluated for repeatability included: clinical score; arterial O2 and CO2 tensions; pulmonary function variables, such as breathing rate (f), tidal volumes, and flow rates; lung resistance (Rl); dynamic compliance; and work of breathing (Wb).

Results
Before challenge, significant differences observed between control horses and horses with heaves included clinical score, expiratory flow rate at near-end expiration, Rl, and Wb. After exposure to moldy hay, variables measured in control horses were largely unchanged. However, in the afflicted horses, significant changes were observed for clinical score, arterial O2 and CO2 tensions, breathing rate, peak tidal inspiratory and expiratory flow rates, dynamic compliance, Rl, and Wb, compared with prechallenge values and with control horses' postchallenge values. Analysis of the data revealed few statistically significant differences between repeats of challenges.

Conclusion
Horses afflicted with heaves manifest airway obstruction that can be measured in repeatable fashion. (Am J Vet Res 1996;57:1214-1219)
In vitro and in vivo effects of activated macrophage supernatant on distal limb wounds of ponies
Authors: Wilson D. A. , Adelstein E. H. , Keegan K. G. , Barrett B. A. , Kutz R. R. 
Published: January 2024

Abstract

Objective
To determine whether monokines produced by activated rabbit peritoneal macrophages can inhibit development of exuberant granulation tissue formation in distal limb wounds in ponies.

Design
Randomized block.

Animals
5 castrated male ponies, 2 to 6 years old and weighing 140 to 190 kg.

Procedure
In vitro activity of cell-free rabbit peritoneal macrophage supernatant was determined after incubation of fibroblasts from the flank and the distal portion of limbs of horses and ponies. Tritiated thymidine was then added, and after reincubation, radioactivity was measured.
After creation of a 4-cm2, full-thickness wound on the mid dorsal aspect of each metacarpus and metatarsus of each pony, in vivo activity of the macrophage supernatant was evaluated. Biopsy specimens were collected at random sites near a border of each wound at 4, 6, and 10 weeks after creation of the wounds. Treatment effects were evaluated on the basis of presence of exuberant granulation tissue requiring excision, number of times that excision was required, total area of the wound, epithelialized area, area of granulation bed, and histologic evaluation of the biopsy specimens.

Results
The macrophage supernatant effectively inhibited proliferation of equine fibroblasts in vitro. No significant in vivo treatment effects were found among the 4 treatment groups.

Conclusion and Clinical Relevance
Monokines from stimulated rabbit peritoneal macrophages may have potential for improving wound healing in horses and ponies because of their effective inhibition in vitro of equine fibroblast proliferation. (Am J Vet Res 1996;57:1220-1224)