bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of in vivo and in vitro corticotropinreleasing hormone-stimulated release of proopiomelanocortin-derived peptides in cats
Authors: Willemse Ton , Mol Jan A.
Published: January 2024

In 6 cats, the effect of iv administration of various concentrations of ovine corticotropin-releasing hormone (ocrh) on plasma concentrations of cortisol, α-melanocyte-stimulating hormone (α-msh), and adrenocorticotropic hormone (acth) was measured. After administration of 1.0 μg of ocrh/kg of body weight, significant (P < 0.05) increases in plasma cortisol, α-msh, and acth concentrations were observed. After administration of 0.1 μg of ocrh/kg, significant increases were found only for cortisol and acth concentrations.

In vitro release of acth from dispersed feline pars distalis cells in primary culture stimulated by ocrh and arginine vasopressin (avp) was dose-dependent. Maximal stimulation was achieved by 1 nM ocrh or 100 nM avp. The ocrh-stimulated acth release was partially inhibited by dexamethasone, and avp-induced release was completely inhibited. Pars intermedia cells released 20 times as much α-msh as acth. A dose-dependent inhibition of α-msh release was induced by the dopamine agonist, bromocriptine. This inhibition could be partially abolished by coincubation with haloperidol. Bromocriptine had no effect on release of acth.

In conclusion, ocrh stimulates the pars distalis and pars intermedia of the pituitary gland of cats. Release of acth is stimulated by a direct effect on the pars distalis. In addition, in cats, ocrh is a more potent secretagogue than is avp. The msh release from the pars intermedia is sensitive to dopaminergic inhibition, indicating that dopamine may have a central role in regulation of msh secretion in cats.
Age-related changes in ocular distances in normal eyes of Samoyeds
Authors: Ehesten Björn , Torrång Ingrid
Published: January 2024

Ocular biometry, using A-scan ultrasonography and ultrasonographic pachymetry, was performed in 52 Samoyeds, 2 months to 13 years old, without intraocular or systemic diseases. Furthermore, the relative depth of the opening of the ciliary cleft was estimated from goniophotographs. The values were analyzed, and statistical models of changes in ocular distances with increasing age were identified. It was found that the changes in corneal thickness, axial anterior chamber depth, lens thickness, relative lens position, length of the vitreous body, and axial length could best be described by 1 of the 2 nonlinear models f(x) = α + β/x + γx + ε and f(x) = α + β/x + γlog x+ε. The course began with a period of rapid increase, after which the ocular distance either increased at a progressively slower rate toward infinity (comeal and lens thickness) or to a finite limit (relative lens position and axial length), or ceased to grow and finally started to decrease toward minus infinity (axial anterior chamber depth and length of the vitreous body). However, suitable model for determining relative depth of the opening of the ciliary cleft could not be established. Results indicated that age-related changes, mainly in lens thickness, cause a shallow anterior chamber, and it was suggested that this may be of importance for development of a relative pupillary block and, thus, primary angle-closure glaucoma, at least in preconditioned eyes of Samoyeds.
Evaluation of lymphocyte stimulation tests for diagnosis of bovine tuberculosis in elk (Cervus elaphus)
Authors: Hutchings Donna L. , Wilson Susan H.
Published: January 2024

Lymphocyte stimulation tests (lst), performed using 6 antigen preparations, were compared individually and in pairs. The tests were performed on 433 blood samples collected from elk in Mycobacterium bovis-infected herds. These elk were killed as part of Agriculture and Agri-Food Canada's bovine tuberculosis eradication policy, and mycobacterial culture results were obtained from tissues of each animal. The lst, which had the highest total sum of sensitivity and specificity, was a comparative test that used M bovis purified protein derivative (ppd) and M paratuberculosis (johnin) ppd. This test had a sensitivity of 76%, with confidence limits (cl) of 63 to 85% for this estimate, and specificity of 77% (cl, 72 to 81%). The lst, using only M bovis ppd antigen, had a sensitivity of 70% (cl, 57 to 80%) and specificity of 74% (cl, 69 to 79%); when it was compared with culture results, using the kappa statistic, agreement was only 32%. This indicated that the lst identified different elk than did M bovis isolation tests.
Comparison of argyrophilic nucleolar organizer regions by counting and image analysis in canine mammary tumors
Authors: Destexhe Eric , Vanmanshoven Pascal , Coignoul Freddy
Published: January 2024

Two techniques for evaluating argyrophilic nucleolar organizer regions (AgNOR) were compared on 74 canine mammary tumors to discriminate between benign and malignant lesions. For each lesion, direct counting of AgNOR on at least 100 cell nuclei was compared with area, perimeter, and integrated optical density AgNOR dot values determined by image analysis. Significant differences between benign and malignant tumors were observed with both methods; however, lesions determined as aggressive or proliferative by histologic evaluation were only singled out by image analysis measurements. Image analysis, in our hands, was a reliable, precise, and convenient technique to characterize malignancy in canine mammary tumors.
Equine herpesvirus 2 in pulmonary macrophages of horses
Authors: Schlocker Nicole , Gerber-Bretscher Rosmarie , von Fellenberg Roland
Published: January 2024

In a search of viral agents in pulmonary macrophages of horses with chronic pulmonary disease, equine herpesvirus 2 was found to be unique. In 8 of 9 horses with chronic pulmonary disease, antigens of equine herpesvirus 2 were detected by indirect immunofluorescence staining of scattered foamy macrophages immediately after harvesting by bronchoalveolar lavage and fractionation on metrizamide gradients. In a healthy horse, antigens were not found. After 1 week of cultivation of bronchoalveolar lavage cells from a second group of 9 horses with chronic pulmonary disease, viral antigens were detected in 90% of the adherent pulmonary macrophages. In 2 of 3 healthy horses, viral antigens also were found in 90% of the adherent pulmonary macrophages. Antigens of equine herpesvirus 1, equine herpesvirus 4, parainfluenza virus 3, or adenovirus were not detected. Antigens of the 5 investigated viruses also were not detected in lung tissue slices from a third group of 14 horses: 4 healthy; 7 with varying degrees of bronchiolitis, 2 of which also had chronic intestitial pneumonia; 2 with eosinophilic bronchitis; and 1 with pulmonary hemorrhage.

The exclusive presence of equine herpesvirus 2 in pulmonary macrophages was confirmed qualitatively by isolation of infective virus by cocultivation. In a fourth group of 12 horses with chronic pulmonary disease, infective virus could be isolated from pulmonary macrophages of 3 horses and from mixed- blood leukocytes of 5 horses. Virus isolations from 2 healthy horses were not successful from pulmonary macrophages, whereas 1 isolation was obtained from mixed-blood leukocytes. Other viruses were not detected by cocultivation.
Influence of a mu- and kappa-opioid agonist on isoflurane minimal anesthetic concentration in chickens
Authors: Concannon Kevin T. , Dodam John R. , Hellyer Peter W.
Published: January 2024

Chickens (n = 18), ranging in age from 30 to 50 weeks and in body weight from 1.1 to 2.1 kg, were anesthetized with isoflurane. Ventilation was controlled, and temperature was maintained at 40.1 ± 1.0 C. The minimal anesthetic concentration (mac) of isoflurane was determined by use of a bracketing technique based on purposeful movement in response to a toe clamp. After determining isoflurane mac in triplicate, birds were given a mu-opioid agonist (morphine, n = 9) or a kappa-opioid agonist (U50488H, n = 9). Determination of mac was repeated after each IV administration of agonist in progressive doses of 0.1, 1.0, and 3.0 mg/kg of body weight. Heart rate and mean arterial blood pressure (MAP) were recorded immediately before and after each injection. Control mac (mean ± SEM) was 1.24 ± 0.05% and 1.05 ± 0.03% for the mu- and kappaopioid agonist groups, respectively. Morphine and U50488H caused a dose-dependent decrease in isoflurane mac in all birds. Reduction of mac from control (mean ± SEM) was 15.1 ± 2.7, 39.7 ± 3.1, and 52.4 ± 4.0% after the 3 successive doses of morphine and was 13.3 ± 3.0, 27.6 ± 3.3, and 40.8 ± 3.8% after U50488H was given. Each opioid injection resulted in significant (P ≤ 0.05, repeated measures anova) lowering of mac. Heart rate and MAP did not change significantly (P ≤ 0.05, paired Student’s t- test) after any dose of opioid. In conclusion, morphine or U50488H decreased isoflurane mac in dose-dependent manner without significant effect on heart rate and MAP.
Persistent anthelmintic activity of ivermectin against gastrointestinal nematodes of cattle
Authors: Williams J. C. , Broussard S. D.
Published: January 2024

Two experiments were conducted to determine persistence of ivermectin (ivm) anthelmintic activity. In the first experiment, the injectable (inj) formulation at a dosage of 200 μg/kg of body weight and pour-on (po) formulation at a dosage of 500 μg/kg were compared in 5 groups of calves (n = 6/group). Calves were treated at 14 and 7 days prior to experimentally induced infection. Experimental groups were: 1-untreated, infected controls; 2-ivm po, day -14; 3-ivm po, day -7; 4-ivm inj, day -14; and 5-ivm inj, day -7. Calves were necropsied on days 28 and 29 after infection. Results of this experiment indicated a high degree of efficacy of ivm po product (93.8%) for all nematodes up to 14 days, in contrast to poor activity for ivm inj (26.3%) for all nematodes. Seven-day persistence was excellent for both ivm formulations against Ostertagia ostertagi and Cooperia spp, but a lower degree of efficacy (77.0% for PO and 88.5% for inj) was observed against Haemonchus placei.

In the second experiment, persistent efficacy of ivm po in preventing establishment of O ostertagi inhibited larvae was observed. In 3 trials, groups of 4 treated and 4 untreated control calves were exposed to natural pasture infection at 0 to 7, 10 to 17, and 20 to 27 days after treatment. Calves were necropsied 15 to 16 days after removal from pasture. After the day 0 to day 7 infection exposure, ivm po efficacy was 100% for all stages of O ostertagi, 3 adult male Cooperia spp, and Oesophagostomum radiatum; 94.9% for H placei; and 98.2% for Cooperia spp adult females. Efficacy values remained high through the day 10 to day 17 infection exposure, ranging from 93.6 to 95.6% for O ostertagi stages, 84.9% for H placei, and 100% for Oes radiatum. However, overall values for Cooperia spp decreased to 69.7%. Efficacy values for the day 20 to day 27 exposure period were 84.5% for O ostertagi adults and 80.7% for H placei. Efficacy against O ostertagi inhibited larvae was 66.4%. With the exception of C pectinata adult males, efficacy against Cooperia spp was zero.
Effects of dexamethasone on cell-mediated immune responses in cattle sensitized to Mycobacterium bovis
Authors: Doherty Michael L. , Bassett Hugh F. , Quinn Patrick J. , Davis William C. , Monaghan Michael L.
Published: January 2024

Systemic administration of dexamethasone led to a significant reduction in the size of the tuberculin reaction in response to intradermal injection of bovine purified protein derivative in 18 cattle experimentally sensitized to Mycobacterium bovis (P < 0.01) and 8 cattle naturally infected with M bovis (P < 0.001). The reaction in 6 of the 7 M bovis-infected cattle that received dexamethasone was classified as negative for the standard interpretation of the single intradermal comparative tuberculin test. Significantly fewer BoCD2+ (P < 0.05) and BoCD4+ T cells (P < 0.001) were present at the reaction site and in blood of dexamethasone-treated cattle, compared with untreated control cattle. Significantly fewer cells expressing the interleukin-2 receptor and WC1+ γδ T cells (P < 0.001), and a significantly greater number of cells expressing the ACT2 antigen (P < 0.05) were found at the reaction site in dexamethasone-treated cattle than in controls. The number of BoCD8+ T cells at the reaction site and in blood was not significantly affected by administration of dexamethasone. In vitro production of interferon-γ by lymphocytes incubated with bovine purified protein derivative also was significantly lower (P < 0.01) in the dexamethasone-treated cattle.
Evaluation of fetal infection and abortion in pregnant ponies experimentally infected with Ehrlichia risticii
Authors: Long Maureen T. , Goetz Thomas E. , Kakoma Ibulaimu , Whiteley Herbert E. , Lock Theodore E. , Holland Cynthia J. , Foreman Jonathan H. , Baker Gordon J.
Published: January 2024

Fetal infectivity of Ehrlichia risticii was investigated in 19 ponies that were E risticii negative on the basis of results of an indirect fluorescent antibody (ifa) test. Thirteen pregnant ponies were infected by iv administration of E risticii between 90 and 180 days of gestation. Six pregnant ponies served as noninfected controls. Each infected pony had clinical signs of equine monocytic ehrlichiosis, was confirmed to be ehrlichemic, and developed an ifa titer to E risticii. Two infected ponies became recumbent, were unresponsive to supportive care, and were euthanatized. After recovery from clinical illness, the remaining ponies were observed throughout gestation for reproductive abnormalities. On abortion, each fetus was necropsied and tissue specimens from the liver, bone marrow, spleen, colon, and mesenteric lymph nodes were inoculated into canine monocyte cell cultures. Six infected ponies aborted at a mean 217 days of gestation, which was between postinoculation days 65 and 111. Five fetuses were recovered for evaluation, and E risticii was isolated from 4 of them. All 5 fetuses recovered had similar histologic findings, including enterocolitis, periportal hepatitis, and lymphoid hyperplasia with necrosis of the mesenteric lymph nodes and spleen. All 5 fetuses tested negative for IgG to E risticii, although 3 had low IgM titer to E risticii. The remaining 5 infected ponies had normal parturition. Presuckle ifa titer to E risticii was measured in 4 of the term foals, and results for 3 were positive. Two foals from infected ponies were monitored for 6 months and daily gain in body weight was comparable to that of a control foal. None of the control ponies became ill or seroconverted during the clinical illness phase, and none aborted throughout gestation. Two control ponies seroconverted to E risticii 6 weeks before parturition. Results of this study indicate that E risticii is a primary abortifacient under experimental conditions.
Comparison of maternal blood and fetal liver selenium concentrations in cattle in California
Authors: Kirk John H. , Terra Ronald L. , Gardner Ian A. , Wright Jim C. , Case James T. , Maas John
Published: January 2024

Selenium concentration was measured in paired maternal blood samples and fetal liver specimens collected at a San Joaquin County, Calif, slaughterhouse (beef = 19, dairy = 54) and from bovine aborted fetuses submitted to the California Veterinary Diagnostic Laboratory System (CVDLS; beef = 20, dairy = 20). Of the slaughterhouse samples and specimens, dairy maternal blood selenium concentration was significantly (P < 0.001) higher (mean ± sd; 0.22 ± 0.056 µg/ml) than that for beef breeds (0.137 ± 0.082 µg/ml). The CVDLS mean maternal blood selenium concentration for the dairy-breed samples (0.192 ± 0.028 µg/ml) was similar to that for the slaughterhouse dairy-breed samples, but was greater than that for the slaughterhouse beef-breed samples. Slaughterhouse mean fetal liver selenium content also was higher (P < 0.001) for the dairy breeds (0.777 ± 0.408 µg/g), compared with the beef breeds (0.443 ± 0.038 µg/g). Mean fetal liver selenium content for slaughterhouse specimens was higher (P < 0.002) than that for the CVDLS specimens (beef, 0.244 ± 0.149 µg/g; dairy, 0.390 ± 0.165 µg/g). At the CVDLS, dairy fetal liver content was greater (P < 0.001) than that for beef breeds. Mean ratio of fetal liver selenium content to maternal blood selenium concentration was 3.53 ± 1.89 for dairy breeds at the slaughterhouse (liver-to-blood correlation [r] = 0.38), and was 2.11 ± 1.00 for dairy breeds at the CVDLS (r = 0.31) and 3.43 ± 1.50 for beef breeds (r = 0.58). Both slaughterhouse breed ratios were significantly (P < 0.002) greater than the CVDLS dairy-breed ratio. On the basis of these results, breed and source location should be taken into account when interpreting selenium values. Fetal liver selenium content should only be used as a screening test and combined with whole blood selenium concentration from clinically normal herdmates to evaluate herd selenium status.
Effect of hypertonic saline solution on left ventricular afterload in normovolumic dogs
Authors: Constable Peter D. , Muir William W. , Binkley Phillip F.
Published: January 2024

The effects of hypertonic saline solution (hss) and hyperosmotic dextrose (hd; 2,400 mosm/L, 4 mV kg of body weight) on left ventricular afterload were determined in normovolumic, chloralose-anesthetized, autonomically blocked dogs (n = 8). Solutions were infused iv over 3 minutes. Left ventricular afterload was assessed by use of a dual-tipped micromanometer catheter with an electromagnetic fluidvelocity sensor located in the ascending aorta, and the impedance spectrum was calculated after Fourier analysis of signal-averaged aortic pressure and flow signals. Hypertonic saline solution and hd decreased peripheral resistance, reflection coefficient at zero frequency, and frequency of the first zero crossing of the phase angle for 3 to 5 minutes after either fluid was administered. Characteristic impedance was not altered by hss or hd. These impedance spectrum changes indicate transient vasodilatation and afterload reduction. We conclude that the vascular effect of an ionic hyperosmotic solution (hss) is similar to that of a nonionic hyperosmotic solution (hd), and that hss and hd transiently decrease afterload in normovolumic dogs. The duration of the afterload reduction after hss administration appeared to be too short to be of great clinical benefit.
Site-specific proteoglycan characteristics of third carpal articular cartilage in exercised and nonexercised horses
Authors: Palmer Jan L. , Bertone Alicia L. , Malemud Charles J. , Carter Barry G. , Papay Robert S. , Mansour Joseph
Published: January 2024

The relevance of site and the influence of exercise on third carpal articular cartilage proteoglycan (pg) were assessed in 16 horses. Six horses were exercised (exercised group) for 30 minutes, 3 times/wk, for 6 weeks. The other 10 horses (nonexercised group) were housed in box stalls for the same 6-week period. At week 6, articular cartilage from the proximal surface of the right third carpal bone was harvested and cultured with radioactive sulfate to label newly synthesized pg. Endogenous pg was measured by use of a uronic acid assay. Newly synthesized and endogenous pg were characterized by use of Sepharose CL-2B chromatography, composite gel electrophoresis, and/or immunoblot analysis with monoclonal antibody 1C6 directed against the hyaluronic acid-binding region on pg.

There was a significant (P = 0.0002) effect of exercise, but not site, on newly synthesized pg, which was increased in the exercised horses, compared with the nonexercised horses at the end of the 6-week study period. The increase in newly synthesized pg was not reflected in the existing cartilage matrix as there was no significant difference between groups in endogenous pg. However, there was a significant (P = 0.01) effect of site on endogenous pg, with the nest of sites located in the palmar aspect of the radial facet containing a greater concentration of endogenous pg than the nests of sites located on the dorsal aspect of the radial facet or all sites on the intermediate facet. Most newly synthesized pg in both groups consisted of hydrodynamically small pg monomers. However, there was a change in the profile of newly synthesized pg at some sites in the exercised horses to include an early elution peak on Sepharose CL-2B, which may contain aggregating pg. All sites in both groups contained a diverse population of endogenous large and small pg on toluidine blue-stained composite gels that reacted with monoclonal antibody 1C6, indicating the potential to bind to hyaluronic acid.
Serum sensitivity of field isolates and laboratory strains of Brucella abortus
Authors: Eisenschenk F. C. , Houle J. J. , Hoffmann E. M.
Published: January 2024

Objective

To evaluate the ability of bovine complement to kill a variety of field isolates and laboratory strains of Brucella abortus.

Design

The experimental approach was to determine the sensitivity of B abortus isolates to killing by bovine serum, and to document the role of complement in brucellacidal activity.

Sample population

Six laboratory isolates and 12 field isolates of B abortus were tested.

Procedure

The ability of B abortus to survive exposure to undiluted bovine serum for 2 hours at 37 C was assessed. The role of complement in killing was determined by examining the ability of heat (56 C for 60 minutes) and cobra venom factor to obliterate the activity in serum, and by detecting binding of the ninth component of bovine complement to serum-sensitive target cells.

Results

Isolates of B abortus that were resistant to the bactericidal activity of normal bovine serum were revealed. These included field isolates and laboratory strains. Furthermore, the study confirmed earlier reports that bovine serum-mediated killing of B abortus is caused by the complement cascade.

Conclusions

Some isolates of B abortus, like other gram-negative bacteria, were resistant to complement-mediated killing. Resistance was associated with smooth colony morphology. Isolates lacking detectable O antigen were serum sensitive.
Comparative cardiopulmonary effects of intramuscularly administered etorphine and carfentanil in goats
Authors: Heard Darryl J. , Nichols Wilmer W. , Buss Daryl , Kollias George V.
Published: January 2024

Objective

To determine comparative cardiopulmonary effects of IM administered etorphine and carfentanil in goats.

Animals

Seven clinically normal adult female goats.

Design

Each goat received at least 9 drug treatments (etorphine HCI, 5 (twice], 10, 20, and 40 and carfentanil citrate, 5, 10, 20, and 40 μg/kg of body weight), with a minimal 2-day interval between trials. Although drug dosages were randomized, etorphine and carfentanil treatments were alternated. To assess for drug tolerance, the first and last treatments always were etorphine (5 μg/kg).

Procedure

All goats were instrumented for long-term cardiopulmonary variable data collection.

Results

Both drugs induced rapid catatonic immobilization, characterized by limb and neck hyperextension, with occasional vocalization and bruxation. Etorphine elicited transient violent struggling and vocalization immediately. Time to immobilization appeared dose-dependent, and was more rapid with carfentanil (≤ 5 minutes) than etorphine (5 to 10 minutes) at all dosages. Recovery to standing occurred earlier for etorphine (1 to 2 hours) than carfentanil (> 2 hours) at all dosages.

Both drugs at all dosages significantly (P ≤ 0.05) increased systemic and left ventricular (LV) end-diastolic pressures, LV peak negative dP/dt, total peripheral resistance (TPR), hemoglobin concentration, and left atrial (LA) and pulmonary O2 contents. They also significantly decreased heart and respiration rates, and TPR. A significant increase was observed at some dosages for LV stroke volume and index, LV peak positive dP/dt, mean pulmonary artery pressure, PaO2, pulmonary artery oxygen partial pressure, PaCO2, pulmonary mixed venous carbon dioxide partial pressure, LA hemoglobin saturation, LA transport index, and body temperature. Pulmonary and systemic mixed venous carbon dioxide and oxygen contents were significantly decreased at some dosages.

Conclusions

Intramuscularly administered etorphine and carfentanil induce hypertension, bradycardia, and bradypnea in goats. The hypertension appears attributable to an increase in TPR.

Clinical Relevance

Although the cardiopulmonary effects of carfentanil occurred more rapidly, these effects were similar in magnitude for etorphine and carfentanil over the evaluated dosage range. (Am J Vet Res 1996;57:87-96)
Detection of foot-and-mouth disease viral sequences in various fluids and tissues during persistence of the virus in cattle
Authors: Bergmann Ingrid E. , Malirat Viviana , Augé de Mello Paulo , Gomes Ivo
Published: January 2024

Objective

To assess whether foot-and-mouth disease virus (FMDV)-specific sequences could be identified in tissues from persistently virus-infected animals.

Design

Cattle with experimentally induced persistent FMDV infections were slaughtered at 750 days after viral exposure. Experimentally infected pigs were slaughtered at 28 days after FMDV inoculation. Postmortem specimens were asceptically removed.

Animals

Three bovids and 3 pigs were studied, as well as 1 control animal for each species.

Procedure

Various tissues were examined for the presence of FMDV-specific sequences by dot-blot hybridization assay, using a molecularly cloned FMDV cDNA corresponding to the polymerase coding region.

Results

The FMDV-specific genomic sequences were only detected in RNA from spleen, lung, larynx, tonsils, pancreas, liver, esophagus, and WBC of bovids.

Conclusions

It was established that, at late stages of the persistent infection, when virus isolation was not possible, cattle may carry FMDV-specific sequences in different tissues. Retention of viral sequences could not be demonstrated in specimens from experimentally infected swine, 28 days after viral inoculation.
Helicobacter mustelae-associated hypergastrinemia in ferrets (Mustela putorius furo)
Authors: Perkins Scott E. , Fox James G. , Walsh John H.
Published: January 2024

Objective

To determine whether ferrets naturally infected with Helicobacter mustelae were hypergastrinemic, compared with ferrets that were specific-pathogen-free (SPF) for H mustelae.

Design

Plasma gastrin concentrations in H mustelae-infected and SPF ferrets were measured at 3 time points and compared to determine whether H mustelae was associated with hypergastrinemia.

Animals

21 H mustelae-infected ferrets and 10 SPF ferrets.

Procedure

The H mustelae status of the ferrets was confirmed prior to commencement of the study. Gastric endoscopy was used to obtain gastric mucosal pinch biopsy specimens that were processed for rapid-urease assay, microaerophilic culturing, and histologic evaluation. Plasma gastrin concentrations were determined at 3 time points: baseline after a 12-hour nonfeeding period, and 30 and 60 minutes after oral administration of a standardized meal. Gastrin was measured by radioimmunoassay.

Results

The results for the H mustelae-infected group (mean ± SEM pg/ml) were: baseline, 54.4 ± 2.56; 30 minutes, 94.5 ± 6.05; and 60 minutes, 82.6 ± 5.73. The SPF group results were: baseline, 55.8 ± 7.35; 30 minutes, 80.8 ± 5.77; and 60 minutes, 59.7 ± 4.95. There was a significant (P < 0.01) difference at the 60-minute time point between the 2 groups of animals. The H mustelae group had a 17% higher mean gastrin value at 30 minutes.

Conclusions

Helicobacter mustelae is associated with hypergastrinemia in ferrets.

Clinical Relevance

Helicobacter-induced hypergastrinemia may be related to the pathogenesis of peptic ulcer disease in ferrets.
Role of prostaglandins and enteric nerves in Escherichia coli heat-stable enterotoxin (STa)-induced intestinal secretion in pigs
Authors: Hayden Ursula L. , Greenberg Richard N. , Carey Hannah V.
Published: January 2024

Objective

To examine the role of prostaglandins and enteric nerves in mediating intestinal secretion induced by enterotoxigenic Escherichia coli heat-stable enterotoxin (STa) in pig jejunum and distal portion of the colon.

Animals

Two- to 3-week-old suckling crossbred pigs were studied.

Design

Changes in ion transport in response to mucosal addition of E coli STa to jejunal and colonic tissues were studied in the presence and absence of inhibitors.

Procedure

Flat sheets of muscle-stripped proximal portions of the jejunum and distal portions of the colon were mounted in Ussing chambers equipped to measure changes in short-circuit current (Isc), a measure of active ion transport. Tissues were exposed to 200 ng of STa/ml administered to mucosal solutions, and subsequent changes in Isc were recorded.

Results

In control tissues, changes in Isc induced by STa in the distal colon were significantly greater (21.4 ± 4 µA/cm2) than those observed in the jejunum (14.0 ± 2 µA/cm2). When either segment was exposed to the neurotoxin, tetrodotoxin, or to the nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl ester, Isc responses to STa were unchanged, suggesting no involvement of submucosal nerves in mediating STa-induced secretion. When tissues from the distal portion of the colon and jejunum were pretreated with piroxicam, a prostaglandin synthesis inhibitor, the STa-induced Isc response was significantly reduced by 52 and 57%, respectively.

Conclusions

These results indicate that the pig jejunum and distal portion of the colon are sensitive to the secretory actions of enterotoxigenic E coli STa, and that the responses are mediated, in part, by release of prostaglandins.
Evaluation of travel and use as a risk factor for seropositivity to Ehrlichia risticii in horses of New York state
Authors: Atwill Edward R. , Mohammed Hussni O. , Lopez Jorge W.
Published: January 2024

Objective

To determine whether mean annual frequency and destination of equine travel was associated with exposure to Ehrlichia risticii and whether these associations were modified by horses’ place of residence.

Design

Cross-sectional study.

Sample Population

511 equine operations containing 2,587 horses were visited in New York state from a target population of 39,000 operations.

Procedure

Each horse was tested for serum antibodies against E risticii, using indirect fluorescent antibody. Information on the horse's travel history, farm's management practices, and surrounding ecology was obtained by personal interview and resource maps. Statistical analyses were performed on 2 cohorts of animals: all horses enrolled in the study and horses born on the property or that resided at least 4 years on the farm. Three countybased risk regions (RR) were identified by use of cluster analysis.

Results

Mean seroprevalence for each of the 3 RR was 2.4 (low risk), 8.5 (moderate risk), and 18.5% (high risk) for cohort 1 and 2.5, 8.0, and 18.4% for cohort 2. Among cohorts 1 and 2, pleasure riding and breeding trips were associated with exposure to E risticii, but horse residence (low, moderate, or high RR) was an effect modifier for these associations. Among cohort 1 and stratifying the analysis according to the RR for the travel destination, trail riding at low RR and trail riding at high RR were associated with exposure. Among cohort 2 and stratifying the analysis according to the RR for the travel destination, breeding trips were associated with exposure, and strong effect modification was present for horse residence (low, moderate, or high RR).

Conclusions

Only certain types of travel to specific RR were associated with higher risk of exposure to E risticii. In many instances, travel was not associated, or was associated, with a reduced risk of exposure.(Am J Vet Res 1996; 57: 272-277)
Serologic responses of cattle and other animals infected with Neospora caninum
Authors: Dubey J. P. , Lindsay D. S. , Adams D. S. , Gay J. M. , Baszler T. V. , Blagburn B. L. , Thulliez P.
Published: January 2024

Objective

To examine cross-reactivity among Neospora caninum and closely-related apicomplexans.

Design

Sera from animals were examined for antibody production to N caninum and cross-reactivity to Toxoplasma gondii.

Animals

Cattle were experimentally infected with 3 tissue cyst-forming protozoan parasites N caninum, T gondii, and Sarcocystis sp, and calves were monospecifically inoculated with the intestinal coccidia, Eimeria bovis and Cryptosporidium parvum. Similar studies were done in laboratory rabbits inoculated with N caninum, T gondii, Hammondia hammondi, and Sarcocystis sp. Additionally, sera were obtained from ewes, lambs, goats, sows, cats, rats, and mice inoculated with N caninum tachyzoites.

Procedure

The indirect fluorescent antibody (IFA) and ELISA antibody tests (cattle only) were used to examine reactivity to N caninum; the modified direct agglutination, Sabin-Feldman dye, and IFA tests were used to evaluate reactivity to T gondii.

Results

Serologic cross-reactivity among N caninum, T gondii, and Sarcocystis sp was none or minimal by the IFA test. There was some reactivity to N caninum by the use of ELISA in cattle inoculated with Sarcocystis sp.

Conclusions

The IFA test for N caninum was specific for the diagnosis of neosporosis in animals.(Am J Vet Res 1996;57:329-336)
Ultrasonography of the lungs, pleura, and mediastinum in healthy cows
Authors: Braun Ueli , Sicher Daniel , Pusterla Nicola
Published: January 2024

Objective

To describe the ultrasonographic appearance of the lungs, pleura, and mediastinum of cattle.

Design

Transcutaneous ultrasonography of the lungs and pleura was performed on the right and left sides of the thorax. The mediastinum was examined transesophageally.

Animals

50 healthy cows.

Procedure

The thoracic wall, pleura, and pulmonary surface were visualized on both sides of the thorax via transcutaneous ultrasonography. The cranial mediastinal lymph node, right azygos vein, aorta, and caudal vena cava were visualized via transesophageal ultrasonography.

Results

The layers of the thoracic wall appeared as narrow bands that varied in echogenicity. They were followed medially by an echogenic line that represented the costal and pulmonary pleurae. Reverberation artifacts were seen medial to the pleura. The pulmonary parenchyma could not be visualized ultrasonographically because of its air content. The cranial mediastinal lymph node appeared circular to oval. The right azygos vein was situated immediately adjacent to the cranial mediastinal lymph node. The aorta appeared circular to oval on cross-sectional view with an echogenic wall and an anechoic lumen. The caudal vena cava appeared as a tubular structure with an anechoic content and an echogenic wall.

Conclusion

Ultrasonography of the lungs, pleura, and mediastinum in healthy cows provides information that can be used as a reference when examining cattle with suspected disease of the thorax. (Am J Vet Res 1996; 57:432–438)
Effects of cisapride on feline colonic smooth muscle function
Authors: Washabau Robert J. , Sammarco Jill
Published: January 2024

Objective

To determine the effects of cisapride on feline colonic smooth muscle function.

Design

In vitro smooth muscle mechanical measurements.

Animals

Intact colon was obtained from healthy 2- or 3-year-old cats.

Procedure

Longitudinal smooth muscle strips from proximal and distal portions of feline colon were suspended in physiologic buffer solution (37 C, 100% O2, pH 7.4), attached to isometric force transducers, and stretched to optimal muscle length. Control responses were obtained at each muscle site with acetylcholine (10−8 to 10−4M), cholecystokinin (10−11 to 10−7M), substance P (10−11 to 10−7M), or neurotensin (10−11 to 10−7M). Muscles were then stimulated with cumulative (10−9 to 10−6M) or bolus (10−6M) doses of cisapride in the absence or presence of tetrodotoxin (10−6M) and atropine (10−6M), nifedipine (10−6M), or calcium-free buffer solution.

Results

Cisapride stimulated contractions of longitudinal smooth muscle from proximal and distal portions of feline colon that were similar in magnitude to contractions induced by substance P and neurotensin. Cisapride contractions were only partially inhibited by tetrodotoxin (10−6M) and atropine (10−6M). suggesting that cisapride responses are only partially dependent on enteric cholinergic nerves. Nifedipine (10−6M) inhibited the maximal contraction to cisapride (10−6M) by approximately 80%. Removal of extracellular calcium did not inhibit cisapride contractions to a greater extent than did inhibition by nifedipine, indicating that calcium influx through voltage dependent calcium channels was predominantly responsible for the dependence of the cisapride contraction on extracellular calcium.

Conclusions

Cisapride-induced contractions of feline colonic smooth muscle are largely smooth muscle-mediated and dependent on calcium influx, and are only partially dependent on enteric cholinergic nerves.

Clinical Relevance

Cisapride may be useful in the treatment of feline colonic motility disorders. (Am J Vet Res 1996;57:541–546)
Effects of potentiated chlorhexidine on bacteria and tarsocrural joints in ponies
Authors: Klohnen Andreas , Wilson David G. , Hendrickson Dean A. , Cooley A. James , MacWilliams Peter S.
Published: January 2024

Objectives

To evaluate the bactericidal properties of chlorhexidine diacetate (CHD) after potentiation with EDTA and Tris buffer (EDTA-Tris), and to find a potentiated CHD concentration that would achieve 90 to 100% killing for all bacteria tested.

Animals

6 adult ponies.

Procedure

Serial dilutions of CHD, CHD in EDTA-Tris, and EDTA-Tris alone were evaluated for bactericidal activity against Staphylococcus aureus, Escherichia coli, and Streptococcus zooepidemicus. The tarsocrural joints of 6 ponies were lavaged with either 1 L of phosphate buffered saline solution (control) or 1 L of 0.0005% CHD in EDTA-Tris. Synovial fluid was collected before lavage and on days 1,4, and 8. Synovia, cartilage, and bone with cartilage were collected on day 8 when the ponies were euthanatized.

Results

In vitro results indicated that 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Results of synovial fluid analysis, glycosaminoglycan analysis, and histologic examination of the synovial membrane and articular cartilage indicated that joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage of pony tarsocrural joints. Changes observed were a result of the actual lavage process, the phosphate-buffered saline solution, and hemarthrosis.

Conclusions

A concentration of 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Pony tarsocrural joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage. The efficacy of 0.0005% CHD potentiated with EDTA-Tris as a potential joint lavage fluid for treatment of infectious arthritis needs to be evaluated in clinical patients. (Am J Vet Res 1996; 57:756–761)
In vitro biomechanical comparison of the strength of the linea alba of the llama, using two suture patterns
Authors: Van Hoogmoed Linda , Snyder Jack R. , Stover Susan M. , Drake Christiana , Taylor Kenneth , Harmon Faye A. , McDuffee Laurie
Published: January 2024

Objective

To compare the strength of the sutured linea alba, in vitro, using 2 suture patterns.

Animals

12 clinically normal llamas.

Procedure

2 incisions in the linea alba of 12 llamas were closed with a simple continuous or inverted cruciate pattern, and tissue was harvested after 10 days. In 6 llamas, the simple continuous line was intact; the inverted cruciate specimens contained 6 sutures. In 6 llamas, 1 knot was excised in the simple continuous pattern to simulate a failed line; the cruciate pattern contained 5 knots. Tissue sections were taken from cranial, between, and caudal to the linea alba incisions to compare fascial thickness. The sutured specimens were mounted in a mechanical testing system and tested to failure. A mixed-model ANOVA was used to evaluate the effects of suture pattern and incisional position on mechanical properties.

Results

Significant differences were not found between suture patterns or between location for yield force, failure force, or yield strain, whereas failure strain was lower for the intact simple continuous pattern than the inverted cruciate pattern (P = 0.003). From histomorphometric analysis, the caudal tissue specimens were significantly thinner than the middle tissue specimen cranial to the umbilicus (P = 0.006).

Conclusion

There was no significant difference in monotonic breaking strength of the linea alba sutured with the simple continuous or inverted cruciate pattern.

Clinical Relevance

These results justify the use of the simple continuous pattern over the cruciate pattern for ventral midline closure in llamas because of the ease of placement and speed. (Am J Vet Res 1996;57:938–942)
Segmental variations of in vitro mechanical properties in equine superficial digital flexor tendons
Authors: Crevier Nathalie , Pourcelot Philippe , Denoix Jean-Marie , Geiger Didier , Bortolussi Claude , Ribot Xavier , Sanaa Moez
Published: January 2024

Objective

To determine the local variations of mechanical properties of the equine superficial digital flexor tendon (SDFT).

Sample Population

10 SDFT of adult horses, selected for absence of abnormality.

Procedure

Needles (with a dark marker at both ends) pinned perpendicularly through each tendon to delimit 7 segments. Each tendon was tested in traction until rupture; test was filmed, using an 8-mm video camera. For each image, the coordinates of the center of mass of each marker and the corresponding force were registered. The third-degree polynomial that best fits the stress-strain curve thus obtained was calculated by a least squares approximation. The modulus of elasticity (Emax) of each segment was evaluated as the maximum of the derivative of this polynomial.

Results

Mean rupture load of the 10 SDFT was 12,356 ± 1,333 N. The strain at tendon rupture and Emaxvaried, respectively, from 8.1 ± 1.3% and 1,002 ± 161 MPa (sesamoidean region) to 12.5 ± 1.7% and 1,189 ± 63 MPa (metacarpal region). The values of the strain corresponding to Emax were remarkably similar along the SDFT (approx 5%).

Conclusions

Emax appeared fairly homogeneous along an SDFT, although being slightly higher in the metacarpal region. The 5% strain corresponding to Emax could be the limit strain beyond which microlesions of the tendinous fibers begin to appear, this threshold being first reached during the traction test by the metacarpal segments. (Am J Vet Res 1996;57:1111–1117)
Effects of fumonisin-containing culture material on pulmonary clearance in swine
Authors: Smith Geof W. , Constable Peter D. , Smith Arnold R. , Bacon Charles W. , Meredith Filmore I. , Wollenberg Gordon K. , Haschek Wanda M.
Published: January 2024

Objective

To determine the potential effects of feeding fumonisin-containing culture material on the pulmonary clearance of blood-borne particulates and bacteria in swine.

Animals

21 healthy male pigs randomly assigned to control and treated groups.

Procedure

Control pigs were fed a standard grower ration while culture material containing fumonisins (20 mg of hydrolyzed fumonisin B1/kg of body weight/d) was added to the feed of treated pigs for 7 days. On day 8, pigs were anesthetized with halothane and catheterized, using a sterile cut-down procedure. 18 hours after recovery from anesthesia, Monastral Blue or Pseudomonas aeruginosa was infused into the right atrium of treated and control pigs for 30 minutes and pulmonary clearance was determined.

Results

Pigs that were fed fumonisin-containing culture material had a significantly (P < 0.05) decreased ability to clear Monastral Blue and P aeruginosa. Ultrastructural examination of the lung indicated that uptake of copper pigment by pulmonary intravascular macrophages was decreased in treated pigs.

Conclusions and Clinical Relevance

Fumonisins, even when fed to pigs at sub-lethal concentrations, can inhibit pulmonary intravascular macrophages from removing particulate matter and bacteria from the circulation, thus potentially predisposing swine to infectious disease. (Am J Vet Res 1996;57:1233-1238)
Toxoplasma gondii antigen recognition by serum immunoglobulins M, G, and A of queens and their neonatally infected kittens
Authors: Cannizzo K. L. , Lappin M. R. , Cooper C. M. , Dubey J. P.
Published: January 2024

Objective

To evaluate antigen recognition patterns of serum IgM, IgG, and IgA from queens and their kittens as a method of diagnosing neonatal toxoplasmosis.

Animals

5 pregnant queens were inoculated orally with Toxoplasma gondii tissue cysts during gestation (18 to 44 days). On various days after parturition (0 to 97), serum was obtained from queens and kittens (n = 19).

Procedure

Tissues from most kittens were assessed for T gondii infection by bioassay in mice. Serum samples were evaluated by IgM, IgG, and IgA western blot immunoassays for the presence of T gondii antibodies. Antigens recognized by kitten serum samples, but not by the corresponding queen serum sample, were considered to indicate neonatal infection with T gondii.

Results

Using the results of western blot immunoassay, 8 of 19 kittens (age, 2 to 97 days) were determined to be infected with T gondii. Western blot immunoassay results correlated well with bioassay results, identifying 7 of 8 bioassay-positive kittens. Western blot immunoassay additionally identified 1 kitten as infected, but tissues from the kitten had not been bioassayed. In each of the 5 kittens that developed clinical signs of toxoplasmosis, the diagnosis of neonatal toxoplasmosis was supported by results of the western blot immunoassays.

Conclusion and Clinical Relevance

Comparison of queen and kitten T gondii antigen recognition patterns of IgM, IgG, and IgA can be used for antemortem diagnosis of neonatal toxoplasmosis. (Am J Vet Res 1996;57: 1327-1330)
Physiologic effects of anesthesia induced and maintained by intravenous administration of a climazolam-ketamine combination in ponies premedicated with acepromazine and xylazine
Authors: Bettschart-Wolfensberger R. , Taylor P. M. , Sear J. W. , Bloomfield M. R. , Rentsch K. , Dawling S.
Published: January 2024

Objective

To examine the physiologic and pharmacokinetic effects of a technique of total intravenous anesthesia in ponies.

Animals

6 healthy ponies.

Procedure

Ponies were premedicated with acepromazine (0.03 mg/kg of body weight, IV) and xylazine (1.0 mg/kg, IV). Two minutes later, anesthesia was induced with ketamine (2.0 mg/kg, IV) followed by climazolam (0.2 mg/kg, IV). Anesthesia was maintained for 120 minutes by an infusion of climazolam (0.4 mg/kg/h) and ketamine (6.0 mg/kg/h). Oxygen (5 L/min) was supplemented. 20 minutes after the infusion was stopped, sarmazenil (0.04 mg/kg, IV) was administered. Cardiovascular and respiratory function measurements were taken before and after premedication, and during anesthesia. Plasma cortisol, ACTH, and catecholamine concentrations were used to assess adrenal and pituitary gland function. Ketamine and climazolam kinetics were calculated, on the basis of plasma drug concentrations.

Results

There were no significant changes from prexylazine values in heart rate, respiratory rate, arterial blood pressure, cardiac index, systemic vascular resistance, or arterial Po2, PCO2, and pH. Plasma cortisol concentration decreased during anesthesia, but plasma ACTH and catecholamine concentrations did not change. Recovery was fairly smooth, but some excitement and ataxia were noted in 2 ponies.

Conclusion

Ketamine-climazolam infusion appeared suitable for maintenance of anesthesia in ponies, although recovery was not ideal in 2 of 6 ponies. (Am J Vet Res 1996;57:1472-1477)