bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of lufenuron against developmental stages of fleas (Ctenocephalides felis felis) in dogs housed in simulated home environments
Authors: Blagbum Byron L. , Hendrix Charles M. , Vaughan Joy L. , Lindsay David S. , Barnett Sharron H.
Published: January 2024

Twenty-four, adult, female Beagles were arranged by body weight from greatest to least and allocated to 2 groups of 12 dogs, using random numbers. Dogs were housed collectively in 2 adjacent metal buildings, each divided into 4 rooms measuring 2.1 × 3.7 m. Each room was paneled and carpeted and had an access door to the outside with a connecting run that measured 2.1 × 9.1 m. Each run had a surface consisting of 5 cm of pea gravel overlaying 5 cm of sand, and was partially covered by an awning that provided shade at its proximal end. For placement in room/run units, dogs in each of the treated and control groups were allotted to 4 subgroups of 3 dogs each. Each subgroup of dogs was placed in a separate room/run unit. Units containing treatment or control subgroups were alternated to avoid placing identically treated subgroups adjacent to each other. Dogs of subgroups A, C, E, and G were treated with lufenuron monthly at a minimal target dosage of 10 mg/kg of body weight; those of subgroups B, D, F, and H were treated with excipient tablets. Dogs were treated on study days 7, 37, 68, and 98. Each dog was infested with 100 newly emerged, unfed, insectary-reared, adult Ctenocephalides felts on each of study days 0 and 2. Thereafter, infestations on all dogs were dependent on continued development of fleas either in the indoor or outdoor environment. Numbers of fleas on each of the treated and control dogs were determined, using a nondestructive counting technique on days 6, 14, 21, 28, 35, 56, 70, 84, 98, 112, and 119. On study day 21 and on each collection day thereafter, numbers of adult fleas recovered from treated dogs were significantly (P < 0.05) fewer than those recovered from control dogs. Proportion reduction of fleas on treated vs control dogs exceeded 90% by study day 35 and 95% by study day 56. Efficacies exceeded 95% on all remaining study days except days 98 (94.4%) and 119 (90%). Results of this study indicate that control of flea populations can be achieved in treated dogs approximately 4 to 5 weeks after initial treatment with lufenuron, and that continued monthly treatments will maintain effective control of flea infestations. Adverse reactions or side effects to treatment with lufenuron were not observed in dogs after treatment at any time throughout the study.
Articular chondrocalcinosis of the humeral head in Greyhounds
Authors: Woodard J. Carroll , Riser Wayne H. , Morrone Augusto A. , Khan Saeed R.
Published: January 2024

Of 143 Greyhounds necropsied consecutively, 6 (4%) had chondrocalcinosis of the scapulohumeral joint; lesions were identified in 6 additional dogs. Lesions were seen exclusively in the humeral head, mainly in the plateau region. The lesions in the dogs of the initial group were unilateral, but 2 of the 6 additional dogs had bilateral lesions. Focal mineralization of articular cartilage appeared as a white raised nidus, sometimes surrounded by a translucent halo in the opaque cartilage. Circular, small translucent cartilage foci, with or without beginning mineralization, were adjacent to definitive chondrocalcinosis lesions. Chondrocyte necrosis and matrix degradation were considered to antedate appearance of matrical mineral granules; mineralization of the cartilage was considered a secondary process, but not necessarily an epiphenomenon. Scanning electron microscopy indicated that the chondrocalcinosis lesion was composed of deposits of irregularly fused stone material that, in scanning and transmission electron micrographs, was composed of irregular spheroids, 0.05 to 0.5 μm in diameter. The spheroids contained poorly formed needle-like crystals of apatite. Sparse transformation of the mineral phase into hydroxyapatite was considered to be attributable to a biological mechanism that inhibited phase transition. Cartilage degeneration and chondrocalcinosis of the plateau region of the humeral head appear to be unique lesions that develop in young Greyhounds. It is possible that these lesions are the result of the biomechanical stress of training and racing.
Cloning and expression of an antigenic domain of glycoprotein gE of pseudorabies virus in Escherichia coli and its use as antigen in diagnostic assays
Authors: Ro L. H. , Lai S. S. , Hwang W. L. , Chou H. H. , Huang J. N. , Chang E. L. , Yang H. L.
Published: January 2024

Use of a combination of an effective gE gene-deleted pseudorabies virus (prv) vaccine with a companion diagnostic kit for prv glycoprotein gE has proven successful in several pseudorabies-eradication programs. To produce a large quantity of functional gE protein for development of a prv-gE diagnostic kit, an Escherichia coli expression system containing the distal region of the prv-gE gene of a prv strain CF was constructed. The expressed protein contained 134 amino adds of gE protein (amino acids 77-210) fused to a 19-amino acids tag containing 6 histidine residues. After induction, a truncated prv-gE polypeptide of 18-kd was expressed to about 20% of the total E coli proteins. Results of immunoblot analysis indicated that this E coli-produced prv-gE protein reacted specifically with serum from prv-hyperimmunized pigs and from field prv-infected pigs, but not with serum samples from specific-pathogen-free pigs or pigs inoculated with gE-deleted prv vaccine. These data indicate that, although the recombinant gE protein is produced in E coli, it still retains the antigenicity of the viral gE glycoprotein. Comparison between the recombinant gE protein, using immunoblot analysis with a commercial gE ELISA containing natural prv-gE protein, revealed comparable test performance. This finding indicated that recombinant gE protein produced by E coli can be used for development of a companion serologic assay for a prv-gE gene-deleted vaccine.
Effects of atipamezole and yohimbine on medetomidine-induced central nervous system depression and cardiorespiratory changes in lambs
Authors: Ko Jeff C.H. , McGrath Charles J.
Published: January 2024

We compared the ability of 2 α2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 ± 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 μg/kg of body weight, IV), followed in 15 minutes by IV administration of atipamezole (30 or 60 μg/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (≤ 70 beats/min) and other arrhythmias did riot occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and Paco2. Arterial oxygen tension was within acceptable range (Pao2, = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change Pao2, significantly. Lambs treated with 30 or 60 μg of atipa- mezole/kg were able to walk unassisted in 2.4 ± 0.4 and 2.3 ± 0.7 minutes, respectively, whereas yohimbine- and saline-treated lambs did not walk unassisted until 15.6 ± 2.7 and 73.0 ± 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs. Atipamezole at dosage of 30 or 60 μg/kg was equally effective, and was more effective in antagonizing medetomidine-induced CNS depression than was yohimbine.
Effects of temperature and storage time on pin pull-out testing in harvested canine femurs
Authors: Huss Brian T. , Anderson Mark A. , Wagner-Mann Colette C. , Payne John T.
Published: January 2024

Effects of temperature and storage time on canine bone-transfixation pin specimens were tested by comparing pin pull-out forces. A total of 16 femurs from 8 mature dogs were tested. Five nonthreaded Steinmann pins were placed through both cortices in the diaphysis of each femur. The femurs were then sectioned transversely between each pin, with a bonepin specimen placed evenly into each of 5 groups prior to biomechanical testing. Four bone-pin specimen groups were stored at −20 or −70 C for 14 or 28 days, while 1 specimen group was immediately tested. Pull-out forces for frozen groups were compared with pull-out forces for the fresh group.

Using two-way anova, there was no statistical difference in mean axial-extraction forces among bonepin specimens in any of the tested groups. It is concluded that acute pin pull-out forces are not significantly affected by freezing temperature or time. However, specimens stored at −20 C for as few as 14 days had a trend for increased pull-out forces, compared with freshly harvested specimens. Therefore, the authors recommend storage of bone-pin specimens at −70 C when possible.
Clinical relevance of the microvasculature of the equine proximal sesamoid bone
Authors: Trumble Troy N. , Amoczky Steven P. , Stick John A. , Stickle Russ L.
Published: January 2024

The blood supply to the proximal sesamoid bone of the equine forelimb was examined in 18 cadaver limbs from adult horses, using x-ray computed tomography and a tissue-clearing (Spalteholz) technique. Results of the study indicated that the proximal sesamoid bones were supplied by multiple branches of the medial and lateral palmar digital arteries, which entered the proximal half of the bones on their non-articular, abaxial surface. After entering the bone, the vessels traverse dorsally, axially, and distally, arborizing into several smaller branches that appear to supply the entire bone. The major branches of these vessels reside in bony canals, the orientation and distribution of which parallel the radiographic lucencies seen in horses with sesamoiditis and correspond to the configuration of apical fracture patterns.
Effects of vascular pedicle ligation on blood flow in canine semitendinosus muscle
Authors: Solano Mauricio , Purinton Paul T. , Chambers Jonathan N. , Munnell John F.
Published: January 2024

Blood flow to the semitendinosus muscle was studied in 12 dogs after ligation of either the proximal or distal vascular pedicle and elevation of the muscle from its normal position. Using 15-μm-diameter radioactive microspheres, flow was measured at rest, 6 and 18 days after muscle elevation and pedicle ligation. Mean blood flow in the proximal region of the muscle 6 and 18 days after ligation of the caudal gluteal (proximal) pedicle was not significantly different from mean blood flow calculated in the middle and distal regions of the muscle. There was also no significant difference in mean blood flow among proximal, middle, and distal regions of the muscle, 6 and 18 days after ligation of the distal caudal femoral (distal) pedicle. There was significantly (P < 0.05) increased blood flow between group-A (ligation of caudal gluteal artery) and group-C (operated-control) muscles, 6 and 18 days after surgery. There was no loss of muscle fiber striations or nuclei, or presence of fibrous tissue that might have indicated ischemic necrosis in any of the experimental groups. These results indicate that the entire semitendinosus muscle can be sustained by the blood flow from either of its 2 vascular pedicles, which reinforces its potential as a muscle flap.
Mural blood flow distribution in the large colon of horses during low-flow ischemia and reperfusion
Authors: Moore Rustin M. , Hardy Joanne , Muir William W.
Published: January 2024

Six horses were subjected to 3 hours of low-flow ischemia and 3 hours of reperfusion of the large colon. After induction of anesthesia, the large colon was exteriorized through a ventral midline celiotomy. Colonic blood flow was measured continuously, using Doppler ultrasonic flow probes placed on the colonic arteries supplying the dorsal and ventral colons and was allowed to stabilize for 15 to 30 minutes after instrumentation. Low-flow ischemia was induced by reducing colonic arterial blood flow to 20% of baseline (bl) flow. Colonic mucosal, seromuscular, and full-thickness blood flow were determined on a tissue-weight basis by injecting colored microspheres proximally into the colonic artery supplying the ventral colon. Reference blood samples were obtained at a known flow rate from the colonic artery and vein at a site more distal to the site of injection. Left ventral colon biopsy specimens were harvested at bl, 3 hours of ischemia, and 15 minutes of reperfusion. Blood and tissue samples were digested and filtered to collect the microspheres, and dimethylformamide was added to release the colored dyes. Dye concentration in blood and tissue samples was measured by use of spectrophotometry, and tissue-blood flow was calculated. Data were analyzed, using two-way anova for repeated measures; statistical significance was set at P < 0.05. Doppler blood flow decreased to approximately 20% of BL, whereas microsphere blood flow ranged between 13.7 and 15.5% of bl at 3 hours of ischemia. Doppler-determined blood flow increased immediately on restoration of blood flow, reached 183% of bl at 15 minutes of reperfusion, and remained at or above bl throughout 3 hours of reperfusion. This reactive hyperemia was also detected, using the colored microspheres; blood flow increased to 242 and 327% of bl at 15 minutes of reperfusion in the mucosal and seromuscular layers, respectively. Mucosal blood flow was not different from seromuscular blood flow at any time, indicating relatively equal distribution of blood flow between these 2 layers. As determined from the venous reference samples, there was no evidence of arteriovenous anastomoses.
Effects of α2-adrenergic receptor agonist and antagonist drugs on cholinergic contraction in bovine tracheal smooth muscle in vitro
Authors: Manning Melanie M. , Broadstone Richard V.
Published: January 2024

Effects of α2-adrenergic receptor stimulation on the cholinergic contractile response of bovine tracheal smooth muscle were studied. To determine the presence and function of α2-adrenergic receptors on cholinergic nerves innervating bovine tracheal muscle, effects of 2 α2-adrenoceptor agonists and an antagonist were determined. Muscular contractions were elicited by either electrical field stimulation (efs) or exogenous acetylcholine (ach).

The contractile response to efs and exogenous ach was examined for each tissue. Electrical field stimulation of bovine tracheal smooth muscle caused contractions that were completely abolished by atropine, indicating the predominant excitatory innervation of bovine trachea is cholinergic. The α2-adrenoceptor agonists clonidine and medetomidine (10-6M to 10-4M) concentration-dependently inhibited the contractile response to efs but not the response to exogenous ach. Contractions induced by efs were significantly (P < 0.05) inhibited in clonidine (10-4M)-treated tissues at low frequencies (0.1 to 10 Hz), whereas medetomidine (10-4M, 10-4M) inhibited contractions at all frequencies (0.1 to 30 Hz). Inhibitory effects of the α2-adrenoceptor agonists clonidine and medetomidine were attenuated by the (α2-adrenoceptor antagonist tolazoline. The α2-agonists used in this study appear to cause prejunctional inhibition of cholinergic nerves, because the smooth muscle contractions elicited by efs, but not exogenous ach, were inhibited, compared with controls.
Pharmacokinetics of heparin and its pharmacodynamic effect on plasma lipoprotein lipase activity and coagulation in healthy horses
Authors: McCann M. E. , Watson T. D. G. , Boudinot F. D. , Moore J. N.
Published: January 2024

We evaluated the pharmacokinetics of iv administered sodium heparin and the pharmacodynamic effect of heparin on lipoprotein lipase (lpl) activity. Horses were allotted to 3 groups. Plasma samples were obtained from each horse before and at various times for 6 hours after heparin administration for determination of heparin concentration, lpl activity, and activated partial thromboplastin time (aptt). The disposition of heparin was dose dependent. The area under the plasma heparin concentration vs time curve (auc) increased more than proportionally with dose, indicating that heparin elimination was nonlinear. Total clearance of heparin was similar after the 40 and 80 IU/kg of body weight dosages, averaging 0.45 and 0.36 IU/kg/min, respectively. However, after administration of the 120 IU/kg dose, clearance was significantly less than that after the 40 IU/kg dose. The half-life of heparin averaged 53, 70, and 136 minutes after 40, 80, and 120 IU/kg, respectively, with significant differences observed between the low and high doses. In contrast to heparin, the area under the plasma concentration vs time curve for lpl activity increased less than proportionally with dose. Maximal lpl activity observed was independent of dose, averaging 4.8 μmol of free fatty acids/ml/h. The aptt was significantly prolonged for 120 minutes after administration of the 40 IU/kg dose. Correlation coefficients for lpl activity vs either plasma heparin concentration or aptt were less than 0.7, indicating that neither laboratory measure can be used to accurately predict plasma lpl activity.
Serologic studies in experimentally induced Salmonella choleraesuis var kunzendorf infection in pigs
Authors: Srinand S. , Robinson R. A. , Collins J. E. , Nagaraja K. V.
Published: January 2024

Two indirect elisa containing outer membrane protein (omp) and lipopolysaccharide (lps) antigens from a field isolate of Salmonella choleraesuis var kunzendorf developed and evaluated in experimentally infected and uninfected control pigs. Experimentally induced infection with S choleraesuis was successfully established in 10 pigs by oral inoculation with 108 organisms, and 3 pigs died of clinical salmonellosis at postinoculation (pi) weeks 1, 2, and 4. Swab specimens from tonsils, nostrils, and rectum of pigs were obtained for culture, and sera were evaluated at weekly intervals for 9 weeks after inoculation. The elisa containing omp and lps antigens with either anti-swine IgG or protein albumin-to-globulin ratio (antiglobulin) conjugates were standardized for serologic evaluation. All 4 elisa (2 omp and 2 lps) detected seroconversion by pi week 3 and had sensitivities and specificities of 97.8 and 88.8, 100 and 100, 95.6 and 88.8, and 93.3 and 72.5%, at their ideal cutoff points (negative mean optical density + 2 sd). There was excellent agreement between all 4 elisa systems as determined by kappa values. Cultures of fecal, tonsil, and nasal swab specimens were positive for S choleraesuis until the fourth week of infection. Fecal swab specimens from 1 pig were positive for S choleraesuis until pl week 7. Persistent infection after antemortem culture results were negative was detected by all 4 elisa, which indicated consistently high titers until the end of pi week 9. Conventional bacteriologic examination of intestines, mesenteric lymph nodes, bone marrow, lung, liver, spleen, and bile yielded positive results for S choleraesuis in the 3 pigs that died of clinical infection, whereas results were negative in the other 7 pigs infected by the end of pl week 9. Histologic examination of lung, liver, spleen, intestines, and mesenteric lymph nodes from the 3 pigs that died of S choleraesuis infection revealed severe ulceration and inflammatory cell infiltration in the lamina propria and submucosa of the intestine, whereas minimal changes were observed in other organs.
Abortions, fetal death, and stillbirths in pregnant pygmy goats inoculated with tachyzoites of Neospora caninum
Authors: Lindsay D. S. , Rippey N. S. , Powe T. A. , Sartin E. A. , Dubey J. P. , Blagburn B. L.
Published: January 2024

Neospora caninum-induced abortion is a major production problem in the dairy cattle industry in the United States and worldwide. Abortions attributable to naturally acquired N caninum infection also have been observed in pygmy goats. We studied experimentally induced infections with N caninum in pregnant pygmy does to determine whether abortions attributable to N caninum infection would occur after inoculation. Seven pregnant pygmy does (1 control doe and 6 inoculated with N caninum) were studied. The control doe remained clinically normal throughout the study and delivered 2 healthy kids. Abortion, fetal death, and stillbirths were observed in some pregnant does inoculated with N caninum. Two pregnant pygmy does inoculated with N caninum early in gestation (day 51) had fetuses that died and were aborted, or died and were reabsorbed. Neospora caninum tachyzoites and lesions were observed in the brain, spinal cord, and heart of aborted fetuses; parasites also were isolated from the placenta. Four additional pregnant pygmy does (2 inoculated at mid-gestation [day 85], and 2 at late gestation [day 127]) did not abort after inoculation. However, 1 doe inoculated during midgestation delivered a stillborn fetus that had died about 1 week prior to parturition. This kid was congenitally infected with N caninum. Neospora caninum was isolated from the placentas of all inoculated does examined. Neonatal neosporosis was not observed in live-born kids, nor were stages of N caninum isolated from any live-born kid. Does did not undergo abortion or have congenitally infected kids when they were rebred and evaluated for neosporosis.
Effect of glucocorticoids on serum osteocalcin concentration in horses
Authors: Geor Raymond , Hope Esther , Lauper Linda , Piela Suzanne , Klassen Joan , King Vicky , Murphy Michael
Published: January 2024

The effects of dexamethasone (0.2 mg/kg of body weight; iv, im, and po) and methylprednisolone acetate (120 mg, given intra-articularly) on serum osteocalcin and cortisol concentrations were studied in 6 horses. Serum osteocalcin and cortisol concentrations were serially monitored after each treatment. A significant (P < 0.05) decrease in serum osteocalcin and cortisol concentrations was observed from 12 to 24 and 2 to 48 hours, respectively, after iv and im administrations of dexamethasone. Serum osteocalcin and cortisol concentrations were significantly decreased from 6 to 48 and 3 to 72 hours, respectively, after oral administration. In contrast, a change in serum osteocalcin concentration was not detected after intra-articular administration of methylprednisolone. Oral, iv, or im treatment with 0.2 mg of dexamethasone/kg caused a decrease in serum osteocalcin concentration in horses.
Vertical loading rates in clinically normal dogs at a trot
Authors: Budsberg Steven C. , Verstraete Mary C. , Brown John , Reece Lynn
Published: January 2024

Present data describe the rates of vertical loading and unloading generated by clinically normal dogs in a trotting gait. Forward velocity was found to influence maximal rates of limb loading and unloading in forelimbs and hind limbs. The rates increased as the velocity of the dog/handler increased. The position of maximal limb loading during the stance phase was independent of velocity in the forelimbs, but in the hind limbs, as velocity increased, the position of maximal unloading occurred earlier in the stance phase.

Within velocity groups, the forelimbs had greater rates of vertical loading and unloading than did hind limbs. The position at which maximal loading occurred was earlier in the forelimbs than in the hind limbs. There was a difference in the position of maximal unloading between forelimbs and hind limbs, with the forelimbs unloading earlier in the stance phase. Difference between paired forelimbs or paired hind limbs was not found for any measurement within any group.

Calculation of loading and unloading rates provides another method of examining functional limb loading in dogs. This method of analysis can be adapted to any animal gaited across a force platform in which single limb strides can be recorded. Calculations can also be done in any axis of measurement. Data indicated loading and unloading rates to be consistent, and easily determined. Use of data generated from rates of limb loading can be classified into 2 areas: documentation of acceptance of load by the limb, and indirect measurement of functional stresses placed on bones of the appendicular skeleton.
Sandwich enzyme-linked immunosorbent assay for quantitative measurement of serum amyloid A protein in horses
Authors: Satoh Megumi , Fujinaga Toru , Okumura Masahiro , Hagio Mitsuyoshi
Published: January 2024

To measure the concentration of serum amyloid A (saa) protein in horses, a sensitive and highly reproducible sandwich (elisa) was established, using affinity purified saa antibody. Results of the elisa were found to have a high correlation (r = 0.95) with those of the single radial immunodiffusion test. Equine saa concentration was measured by use of this elisa. In clinically normal horses, the concentration of saa was high immediately after birth to 2 weeks of age. After that, saa concentration had periodic fluctuations in the range of approximately 10 to 30 μg/ml. Mean (± sd) concentrations of saa in foals (≤ 12 months old) and adult horses (≥ 18 months old) were 21.23 ± 12.20 and 14.93 ± 9.07 μg/ml, respectively. In mares during the perinatal period, saa concentration remained stable within the reference range before parturition. It increased quickly after delivery, and reached a peak value of 101.29 ± 98.82 μg/ml on postpartum day 3, then began to decrease, at postpartum week 2, to the reference range by the end of postpartum month 1. In horses with experimentally induced inflammation, saa concentration increased quickly and reached approximately four- to 40-fold increase over the pretreatment value on day 1 and remained high on days 2 to 6 after treatment. It then returned to the baseline value by 2 to 4 weeks in association with disappearance of local signs of inflammation. The saa concentration was high in most horses with clinical signs of inflammation. It was concluded from these data that this elisa is sensitive and reliable for measuring saa in horses.
Evaluation of multiple doses of 4 and 6% timolol, and timolol combined with 2% pilocarpine in clinically normal Beagles and Beagles with glaucoma
Authors: Gelatt Kirk N. , Larocca Robert D. , Gelatt Justina K. , Strubbe D. Todd , MacKay Edward O.
Published: January 2024

Topically applied 4% timolol, 4% timolol combined with 2% pilocarpine, 6% timolol, and 6% timolol combined with 2% pilocarpine were evaluated in clinically normal Beagles and Beagles with glaucoma. The drugs were instilled twice daily for 5 days. Changes in intraocular pressure (iop), pupil size, and heart rate were recorded on days 1, 3, and 5 at 0, 2, 5, and 8 hours, starting at 8:30 am. In clinically normal dogs, 4 and 6% topically administered timolol did not cause consistent reductions in iop; however, with addition of 2% pilocarpine, iop was consistently lower. In the Beagles with glaucoma, 4 and 6% timolol and, to a greater extent, 4 and 6% timolol combined with 2% pilocarpine lowered iop. The combinations lowered iop and reduced pupil size consistently. In all test groups, either 4 or 6% topically applied timolol caused approximately 10% decrease in mean heart rate.
Ocular squamous cell carcinoma in Simmental cattle in Zimbabwe
Authors: Den Otter Willem , Hill F. W. Graham , Klein Wim R. , Everse Linda A. , Ruitenberg E. Joost , Van der Ven Leo T. M. , Koten Jan Willem , Steerenberg Peter A. , Faber Joop A. J. , Rutten Victor P. M. G.
Published: January 2024

In Zimbabwe, ocular squamous cell carcinoma (oscc) was frequently observed in 5 breeding herds of Simmental cattle, a Bos taurus breed originating from Switzerland. In these herds, initial signs of oscc were already noticeable in cattle about 3 years old. Gradually, oscc prevalence increased, and 36 to 53% of cattle over 7 years old had 1 or more tumors. More tumors developed in Simmental cattle with periorbital white skin than in cattle with periorbital pigmented skin. Other breeds of cattle (eg, Friesian) also are partly white-faced and live in Zimbabwe in a comparable environment; yet, oscc prevalence was lower in those breeds.
Enzyme-linked immunosorbent assay for screening of milk samples for Salmonella typhimurium in dairy herds
Authors: Hoorfar J. , Wedderkopp A.
Published: January 2024

We investigated the ability of an antibody-specific, O antigen-based elisa to document Salmonella typhimurium herd infections by screening of milk samples. Three cattle populations, 20 herds with no history of salmonellosis, 8 herds with history of S typhimurium epsiodes within the previous 7 months, and 220 herds of unknown disease status, were tested. A herd was considered elisa positive if at least 5% of the cows had OD values > 0.3. Among the 20 herds without history of salmonellosis, only 2 herds were elisa positive, whereas all 8 herds with a known history of salmonellosis were elisa positive (herd specificity, 0.9 and herd sensitivity, 1.0). A significant correlation (P < 0.001) was found between the OD values of serum and milk samples from cows in the herds with a history of salmonellosis. It was concluded that elisa testing of individual milk samples can be used for surveillance of herds for S typhimurium infections, but further modifications are needed to test bulk tank milk samples.
Development and characterization of a flow cytometric assay for detection of platelet-bound immunoglobulin G in dogs
Authors: Lewis David C. , McVey D. Scott , Shuman Wilma S. , Muller Wayne B.
Published: January 2024

Objective

To develop a flow cytometric assay for detection of platelet-bound IgG in dogs.

Sample Population

Negative-control platelets were obtained from 5 clinically normal Greyhounds. Positive-control platelets were platelets from 1 clinically normal dog, sensitized with dog anti-canine platelet alloantibodies.

Procedure

Washed platelets were incubated with mouse anti-canine IgG conjugated to fluorescein isothiocyanate and analyzed by flow cytometry. Optimal dilution of antibody reagent and dose-response were determined, as were effects on platelet-bound IgG detection of storage time and temperature of K3EDTA-anticoagulated blood samples, variable platelet numbers, and variable filling of K3EDTA evacuated tubes.

Results

A 1:128 dilution of antibody reagent was optimal. There was a linear increase in platelet-bound IgG when normal canine platelets were incubated with increasing concentrations of positive-control serum. Variable numbers of positive-control platelets tested and variable filling of K3EDTA evacuated tubes had no significant effect on platelet-bound IgG concentration. Platelet-bound IgG concentration increased with storage time at room temperature (P = 0.0003), but not when blood was kept cool. Sufficient platelets for assay were able to be isolated from 3 ml of blood from 5 dogs with < 10,000 platelets/μl.

Conclusions

This assay for platelet-bound IgG in dogs is simple, repeatable, and practical. The assay is not affected by platelet count or variable filling of evacuated tubes, and requires only 3 ml of K3EDTA-anticoagulated blood. Blood samples for testing require packaging on ice and overnight delivery but, after arrival at the laboratory, can be refrigerated and analyzed within 72 hours of collection.

Clinical Relevance

Assays for platelet-bound IgG may help in assessing causes and treatment of thrombocytopenia.
Effect of diethylstilbestrol or zeranol on fetal development, gestation duration, and number of offspring in NMRI mice
Authors: Pérez-Martínez C. , García-Iglesias M. J. , Bravo-Moral A. M. , Ferreras-Estrada M. C. , Martínez-Rodríguez J. M. , Escudero-Díez A.
Published: January 2024

Objective

To evaluate the effects of diethylstilbestrol (des) or α-zearalanol (zeranol) on fetal development, gestation duration, and number of offspring.

Design

Study effects of prenatal administration of des or zeranol on various pre- and perinatal variables in an experimental group of mice, compared with effects in a control group.

Animals

Pregnant NMRI mice.

Procedure

Diethylstilbestrol or zeranol (150 mg/kg of body weight) or vehicle (controls) was administered sc to pregnant mice on days 9 and 10 of gestation. Fetuses from pregnant mice of each group were counted and weighed, and their size and head length were recorded. Additional pregnant mice delivered their fetuses naturally, and pups from each group were counted and their sex was determined. At the end of gestation, abortions were evaluated. All data were statistically analyzed.

Results

Mean number of fetuses was significantly lower (P < 0.0001) in des-treated (4.59 ± 0.48) than in control mice (8.33 ± 0.49). Both estrogenic substances significantly reduced fetal size and weight (P < 0.0001), compared with control mice. Diethylstilbestrol significantly increased abortion frequency (P < 0.0001) and gestation duration (P < 0.0001), compared with values for control mice. A reduced number of live pups (P < 0.0001) from pregnant mice administered des (5.48 ± 0.38) or zeranol (5.97 ± 0.49) was observed, compared with control mice (8.52 ± 0.50), because of reduced number of male offspring (P < 0.0001).

Conclusions

Diethylstilbestrol or zeranol administered during mid-pregnancy leads to decreased fetal weight and size and lower numbers of male offspring at birth. Likewise, des induced a significant increase in abortions and gestation duration.
Detection of strain-specific antigenic epitopes on the lipo-oligosaccharide of Haemophilus parasuis by use of monoclonal and polyclonal antibodies
Authors: Zucker Bert A. , Baghian Abolghasem , Truax Robert , O’Reilly Kathy L. , Storz Johannes
Published: January 2024

Objective

To investigate the antigenic diversity of lipo-oligosaccharides of Haemophilus parasuis.

Procedures

Immunoblot assays were done with monoclonal and polyclonal antibodies on whole-cell lysates. Individual colonies of H parasuis strains H 54, H 53, and H 128 were tested for reactivity with lipo-oligosaccharide-specific monoclonal antibodies after a single passage on chocolate agar, and colonies of strain H 54 were analyzed after 10 passages. Colony blot tests were used to screen H parasuis strains for spontaneously occurring antigenic variation in their lipo-oligosaccharides.

Results

Eight H parasuis strains were separated into 4 lipo-oligosaccharide serovars on the basis of immunoblot reactions with 3 polyclonal rabbit antisera. Nine monoclonal antibodies against lipo-oligosaccharides of a lipo-oligosaccharide-serovar I strain reacted with all tested serovar I strains but failed to react with other H parasuis strains.

Conclusions

Variations in the antigenic reactivity after 1 or 10 passages on chocolate agar were not observed. The serovar I lipo-oligosaccharide strains included virulent as well as avirulent H parasuis strains, indicating that these epitopes do not correlate directly with virulence properties of H parasuis. (Am J Vet Res 1996;57:63-67)
Ampicillin and amoxicillin residue detection in milk, using microbial receptor assay (Charm II) and liquid chromatography methods, after extra-label administration of the drugs to lactating cows
Authors: Anderson Kevin L. , Moats William A. , Rushing John E. , Wesen Donald P. , Papich Mark G.
Published: January 2024

Objective

A microbial receptor assay method (MRAM; Charm II test) for β-lactam antibiotics and a liquid chromatography (LC) method with a detection limit of 2 to 5 ppb were evaluated for detection of ampicillin or amoxicillin residues in milk samples from individuell cows.

Design

The MRAM was compared to the LC in 2 respects. Measured concentrations of drugs were compared, as well as the classification of samples relative to the FDA tolerance value of 10 ppb.

Animals

A total of 6 clinically normal lactating Holstein cows were used per drug.

Procedure

Ampicillin trihydrate or amoxicillin trihydrate was administered at an extra-label dosage of 22 mg/kg of body weight, IM, once to each of 6 cows/drug. Milk samples were collected at milkings prior to and for 156 hours after drug administration. Drug concentrations in milk samples from individual cows were determined by use of the MRAM and LC tests. Additionally, the classification of milk samples relative to the presence or absence of residues above the FDA tolerance value was determined. Pharmacokinetic analysis was performed on derived milk drug concentrations.

Results

Concentration of ampicillin in milk samples from all cows was < 10 ppb by the MRAM and LC methods by the fourth milking (48 hours) after treatment with ampicillin. Values were < 10 ppb by both methods for all cows treated with amoxicillin by the sixth milking (72 hours) after treatment. For individual milk samples, significant differences were found between test methods in the proportion of positive (failing) tests; the MRAM had a higher proportion of presumptive positives.

Conclusions

Even at an extra-label dosage of 22 mg/kg, IM, milk residues > 10 ppb (the FDA tolerance value) were not detected beyond the label milk withholding times for ampicillin (48 hours) and amoxicillin (96 hours). When used for testing milk of individual cows by the control point procedure, the MRAM had a tendency to give presumptive positive test results for milk samples containing < 10 ppb ampicillin or amoxicillin as determined by LC. (Am J Vet Res 1996;57:73-78)
Use of hypertonic saline-dextran solution to resuscitate hypovolemic calves with diarrhea
Authors: Constable Peter D. , Gohar Hani M. , Morin Dawn E. , Thurmon John C.
Published: January 2024

Objective

To determine effectiveness of a new and practical method for fluid resuscitation of dehydrated diarrheic calves.

Design

Animals randomly allocated to 4 groups with appropriate controls.

Animals

16 healthy male dairy calves, 3 to 6 days old.

Procedure

After instrumentation and recording baseline data, diarrhea and hypovolemia were induced by administering milk replacer (33 ml/kg of body weight) and isotonic sucrose solution (2 g of sucrose in 19.5 ml of water/kg, PO) every 8 hours, and furosemide (2 mg/kg, IM) every 4 to 8 hours. Administration of milk replacer and furosemide was discontinued when calves became 6% dehydrated. Calves were then randomly allocated as: control (no treatment); hypertonic saline-dextran (HSD) solution (4 ml/kg, 2,400 mOsm/L NaCl in 6% dextran-70, administered once over 4 minutes, IV); isotonic alkalinizing oral electrolyte solution (55 ml/kg, PO, q 8 h); and HSD-oral electrolyte solution (combination of HSD and oral treatments). Calves were monitored for 24 hours after treatment.

Results

Significant changes included moderate dehydration (8% body weight), marked lethargy, decreased cardiac output and plasma volume, and increased blood lactate concentration, hematocrit, and serum concentrations of albumin, creatinine, sodium, and phosphate. Control calves continued to be lethargic and dehydrated, with significant increases in hematocrit and serum creatinine concentration. Increase in cardiac output and plasma volume was transient in the HSD group and waned by 2 to 8 hours after treatment. Oral electrolyte fluid administration caused slow and sustained increase in cardiac output and plasma volume, and decrease in heart rate, blood lactate concentration, and hematocrit. Combined administration of HSD-oral electrolyte solution caused immediate and sustained increase in cardiac output and plasma volume, and decrease in heart rate, blood lactate concentration, and hematocrit.

Conclusions and Clinical Relevance

Treatment of hypovolemic diarrheic calves with IV HSD and oral electrolyte solution is superior to administration of either solution alone. (Am J Vet Res 1996;57:97-104)
Effect of heartworm infection on fade of norepinephrine-induced constriction in canine pulmonary vein
Authors: Mupanomunda Maria , Williams Jeffrey F. , Kaiser Lana
Published: January 2024

Objective

To test the possible role of endothelial cells in mediating fade of norepinephrine-induced constriction and the effect of heartworm infection on these responses.

Design

Rings of pulmonary vein from control and heartworm-infected dogs were constricted with norepinephrine (10−5.5M) and followed over 65 minutes. Time profiles were established by measuring active tension every 2 minutes for the first 10 minutes, then every 5 minutes for 15 minutes, then every 10 minutes for 40 minutes. Time profiles were done in pulmonary vein rings with and without endothelial cells, and in the presence and absence of N-nitro-L-arginine methyl ester (L-NAME; nitric oxide synthase inhibitor), mefenamic acid (cyclooxygenase inhibitor), or methylene blue (guanylate cyclase inhibitor).

Animals

12 noninfected control and 11 heartworm-infected dogs.

Results

Pulmonary vein constricted with norepinephrine spontaneously loses tension (fades) over time. Fade was not different between control and heartworm-infected dogs. In pulmonary vein from control dogs, methylene blue decreased fade while L-NAME and mefenamic acid did not. In pulmonary vein from heartworm-infected dogs, L-NAME and methylene blue significantly decreased fade, but mefenamic acid did not.

Conclusion

Nitric oxide, but not cyclooxygenase products, mediates fade of norepinephrine-induced constriction in pulmonary vein from heartworm-infected dogs. In control dogs, neither nitric oxide nor cyclooxygenase products appear to be involved in fade. We conclude that in canine pulmonary vein, fade of norepinephrine-induced constriction is mediated, in part, by endothelial cells.

Clinical Relevance

Altered production of endothelium-derived relaxing factors may be important in the pathogenesis of heartworm disease.
Plasma, urine, and synovial fluid disposition of methylprednisolone acetate and isoflupredone acetate after intra-articular administration in horses
Authors: Lillich J. D. , Bertone A. L. , Schmall L. M. , Ruggles A. J. , Sams R. A.
Published: January 2024

Objective

To document plasma, urine, and synovial fluid disposition of 2 common intra-articularly administered steroid preparations, methylprednisolone acetate (MPA) and isoflupredone acetate (IPA).

Design

Descriptive investigation.

Sample Population

100 mg of MPA or 4 mg of IPA was administered to 2 groups of 4 healthy sound radiographically normal female horses.

Procedure

Blood samples were collected at time 0 (before) and 2, 4, 6, 8, 10, 12, 24, 36, 48, 72, and 96 hours after administration of the designated steroid. Complete urine collection for measurement of designated steroid was accomplished by use of occluding 28-F balloon catheters. Synovial fluid samples were aseptically aspirated from the injected and contralateral uninjected tarsocrural joint at time 0 and 8, 24, 48, 240, and 672 hours after administration of the designated steroid. All samples were screened by ELISA to detect parent drug or metabolite equivalent, with a sensitivity of 2.5 ng/ml for MPA and 0.1 ng/ml for IPA. If drug was detected by ELISA in the plasma or synovial fluid, the samples were further quantified and specified, using HPLC with a lower limit of quantification (10 ng/ml).

Results

Between 2 and 12 hours after administration, plasma contained < 10 ng of MPA or IPA/ml (parent drug or metabolite equivalent), as intermittently detected by ELISA. Parent drug or metabolite equivalent was detected in the urine for 24 and 72 hours after injection of IPA and MPA, respectively. Synovial fluid from the contralateral joint contained no detectable MPA or IPA at any sample collection time. Median half-life for MPA, as detected by HPLC, was 10.3 hours (range, 6.1 to 10.6) in the synovial space. Median half-life for methylprednisolone, as detected by HPLC, was 10.4 (range, 9.9 to 32.1) hours.

Conclusions

Both steroids appeared to be rapidly hydrolyzed to their respective ester forms, as detected by HPLC. The ELISA appeared to be a useful screening tool for detection of corticosteroids in this variety of body fluids.
Familial basis of exertional rhabdomyolysis in Quarter Horse-related breeds
Authors: Valberg Stephanie J. , Geyer Charles , Sorum Sandra A. , Cardinet George H.
Published: January 2024

Objectives

To trace pedigrees from affected horses, identify likely contributing founder horses, and determine the conditional probability of founder genotypes.

Design

Muscle biopsy records from the Neuromuscular Disease Laboratory at the University of California-Davis and the University of Minnesota were searched to identify horses with a polysaccharide storage myopathy and exercise intolerance/rhabdomyolysis. Pedigrees containing 5 to 6 generations were obtained where possible.

Animals

13 Quarter Horses, 4 American Paint Horses, 3 Appaloosas, and 3 Quarter Horse crossbreds (16 mares, 4 geldings, and 3 stallions) were identified with polysaccharide storage myopathy. Pedigrees were available for 18 horses.

Procedure

Inbreeding coefficients, founder contributions, and conditional probability of founder genotypes were calculated.

Results

Three stallions (A, B, and C) were featured prominently in the pedigrees. Stallions A and B descended from a common sire. On average, A contributed 8.8% (range, 0 to 23%) of the genes in affected horses, B contributed 4.2% (range, 0 to 14%), and C contributed 3.0% (range, 0 to 14%). The sire and dam of 4 horses were descendants of stallion A, the sire and dam of 1 horse were descendants of stallion B, and the sire and dam of 11 horses were descendants of a combination of stallions A and B. The pattern of inheritance resembled an autosomal recessive disorder. Assuming this pattern of inheritance, the conditional probability that these founders were carriers or recessive for the trait was > 99.29% for stallions A and B and 92% for stallion C.

Conclusions

Results support a familial basis for polysaccharide storage myopathy and associated exertional rhabdomyolysis in Quarter Horse-related breeds. The strong contribution of particular founder stallions to the gene pool in some lines of Quarter Horses may explain the high incidence of exertional rhabdomyolysis in these horses.(Am J Vet Res 1996; 57: 286-290)