bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of virulence and pathogenesis of a canine strain of Leishmania leishmania infantum in hamsters and dogs
Authors: Binhazim Awadh A. , Chapman Willie L. , Shin Sung S. , Hanson William L.
Published: January 2024

Visceral leishmaniasis was experimentally induced in hamsters by the intracardiac inoculation of 107 amastigotes of Leishmania leishmania infantum of canine origin. At postinoculation (pi) days 7, 21, 42, and 63, hamsters were euthanatized. Body weights and total parasite numbers of the liver and spleen were determined. Gross and histologic evaluations of tissues were done. Dogs also were inoculated IV with 108 amastigotes/kg of body weight. Samples were obtained from dogs prior to infection and at biweekly pi intervals for CBC and serum chemical analysis, for lymphocyte blastogenic assay by use of blood leukocytes, and for ELISA to determine antileishmanial antibody titers. At pi week 12, dogs were necropsied; organ weights, tissue imprints of the liver and spleen, and histologic interpretations of tissues were obtained.

Hamsters developed high parasite numbers within 7 days after inoculation, at which time the total parasite numbers in the liver (3.51 × 107 amastigotes) was observed to be approximately 11 times that in the spleen (2.93 × 106). The liver had the highest parasite numbers throughout the infection period. Some infected hamsters became either cachectic and emaciated or ascitic. Two of the 10 infected hamsters died at pi days 54 and 58. Moderate to severe hepatosplenomegaly with granulomatous inflammatory reactions characterized by the presence of varied numbers of parasitized macrophages, giant cells, and hepatic Schaumann bodies were observed in infected hamsters. Infected dogs developed significantly altered hematologic values consisting of mild anemia and moderate leukopenia at pi weeks 8 to 12. Hyperproteinemia characterized by hyperglobulinemia (4.5 g/dl) was noticed at pi week 4. Serum globulin values remained high and increased to > 5.0 g/dl at pi weeks 8, 10, and 12. At pi week 4, ELISA titers were > 16. By pi week 12, all infected dogs had titers > 1,024. The dog with the highest antibody titer had the lowest number of parasites and mild pathologic changes. Evidence of lymphoproliferative response was not noticed up to pi week 12. Similarities between infected hamsters and dogs included the presence of higher parasite numbers in the liver than in other organs. The highest total parasite numbers in the spleen and liver were 1.12 × 109 and 2.86 × 109, respectively. Mild to moderate granulomatous inflammatory reactions were observed in the liver, spleen, thymus, and lymph nodes. Within 12 weeks after inoculation, parasitized macrophages were found in the dermis.

The overall results indicate that hamsters are highly susceptible to experimental infection, and that infected hamsters develop findings similar to those in natural human infections. Our findings also indicate that dogs are susceptible and develop high antileishmanial titers that correspond to low parasite numbers. This suggests the possible role of antibody in determining the seriousness of disease.
Infection rates, disease frequency, pilin gene rearrangement, and pilin expression in calves inoculated with Moraxella bovis pilin-specific isogenic variants
Authors: Ruehl W. W. , Marrs C. P. , George L. , Banks S. J. M. , Schoolnik G. K.
Published: January 2024

Pili have been implicated as virulence factors that result in increased infcctivity of Moraxella bovis, the causative agent of infectious bovine keratoconjunctivitis (ibk). Healthy calves' eyes were inoculated with I- or Q-piliate or nonpiliate M bovis Epp63 to compare the pathogenicity of these isogenic variants. Pathogenicity was determined by the rate of persistent M bovis infection and the prevalence of clinical IBK. Inoculation with M bovis expressing the Q pili resulted in the highest frequency of infection and ibk, whereas I-piliate M bovis elicited a lower rate and nonpiliate M bovis did not result in infection.

In vivo pilin gene rearrangement and pilin-type switching were evaluated by DNA hybridization and immunoblot. Gene rearrangement and type switching varied dependently, and were observed only in eyes inoculated with Q-piliate M bovis. This study suggests that Q pili are specific for colonization of bovine corneal epithelium, whereas I pili enable maintenance of an established infection.
Differential study of electrocardiographic intervals in two neonatal crossbred swine
Authors: Rubio M. Dolores , Tovar Pura , Santisteban Rafael , de Oliveira Manoel , Castejón Francisco
Published: January 2024

The influence of the QT, TQ, and ST intervals, and heart score on both cardiac cycle duration (RR) and diastole/systole (D/S) quotient were analyzed during the neonatal (1 day and 5 days) pigs belonging to 2 crossbreeds of different rusticity, Landrace × Belgian White (LBW) and Landrace × Duroc Jersey (LDJ). Our findings indicate that the shortening of the RR interval in 5-day-old pigs of both crossbreeds was determined by different variables in each breed. In LDJ pigs, this shortening was only associated with a shortening of ventricular activation, and in each age group, the systole and the diastole contributed equally to the RR value. The D/S quotient did not differ significantly in 1-day-old vs 5-day-old pigs, and at both ages, the quotient was only determined by the TQ value. In LBW pigs, the RR, QT, TQ, and ST were shortened, but only the shortening of QT was significant as a result of an acceleration of the ventricular recuperation process. Moreover, differences were found between 1-day-old vs 5-day-old pigs with regard to the contribution of the different intervals to the RR duration. In 1-day-old pigs, the RR depended closely on the TQ, whereas in 5-day-old pigs, all intervals contributed significantly to its duration. The D/S quotient was not significantly different in 1-day-old vs 5-day-old pigs, but a different contribution of the variables studied was observed at the 2 ages selected. In 1-day-old pigs, D/S quotient depended on the diastole duration, whereas in 5-day-old pigs, the diastole and systole contributed to its variation.
Intrastadial and interstadial transmission of Anaplasma marginale by Boophilus annulatus ticks in cattle
Authors: Samish M. , Pipano E. , Hadani A.
Published: January 2024

The 1-host tick Boophilus annulatus was found to transmit anaplasmosis in cattle transstadially. Anaplasma marginale was invariably transmitted when ticks that had been pulled off Anaplasma-infected calves either after 7 days (as fully engorged larvae) or after 14 to 15 days (as fully engorged nymphs) were transferred within 4 days to susceptible calves. Three morphologically different A marginale isolates, 1 round (tailless) and 2 with different types of appendages (tailed) were transmitted by the ticks. These findings might explain the overlap of the geographic distribution of the disease and that of Boophilus spp in some areas of the world.
Electrocardiographic findings in rats with cardiomyopathy
Authors: Pocchiari Ronald J. , Hamlin Robert L. , McCune Sylvia A.
Published: January 2024

The purpose of this study was to evaluate changes in the ecg in a strain of rats, SHHF/Mcc-cp that developed cardiomyopathy and congestive heart failure naturally. Lead-I, -aVF, and -V5 ecg were obtained from male rats at approximately 6, 10, and 19 months of age, corresponding to early, mild, and severe heart failure, respectively. Electrocardiograms also were obtained from male Wistar-Furth rats matched for age with SHHF/Mcc-cp rats. Heart rate, amplitude and duration of component deflections, degree of notching of P waves and QRS complexes, and orientation of means QRS vectors in the frontral plane were analyzed from the ecg. Durations of P waves, PQ intervals, QRS complexes, and QT intervals were prolonged and amplitude of R waves in lead aVF was decreased only in SHHF/Mcc-cp rats at the 19-month recording. Increased notching in QRS complexes, but not in P waves, was observed more frequently at all ages, in SHHF/Mcc-cp rats than in Wistar rats, and notching was greatest at 19 months. Arrhythmias were not observed in Wistar rats, but infrequent supraventricular premature depolarizations were observed in 2 of 10 SHHF/Mcc-cp rats at 19 months. In leads aVF and V5, T waves increased in amplitude as Wistar rats aged; however, in SHHF/Mcc-cp rats, T-wave amplitude peaked in all leads at 10 months, but returned to the 6-month value at month 19. We conclude that cardiomyopathy, heart failure, or both, resulted in changes in the ecg, but that these changes could be used to detect heart failure only when rats reached 19 months of age and were severely affected.
Preparation and transfusion of canine platelet concentrates
Authors: Abrams-Ogg Anthony C. G. , Kruth Stephen A. , Carter Ronald F. , Valli Victor E. , Kamel-Reid Suzanne , Dubé Ian D.
Published: January 2024

A protocol was developed for preparation of platelet concentrates (pc) to support thrombocytopenic dogs. Four clinically normal dogs with platelet counts that ranged from 200 to 330 × 109 platelets/L were used as donors. One unit (450 ml) of blood was collected by venipuncture into a double blood bag. Whole blood (wb) was centrifuged for 4 minutes at 1,000 × g (braking time = 2 minutes, 30 seconds) to prepare platelet-rich plasma (prp). The prp was expressed into the satellite bag and was centrifuged for 10 minutes at 2,000 × g (braking time = 2 minutes, 36 seconds). The platelet-poor plasma was expressed, leaving 40 to 70 ml of plasma and the pelleted platelets in the satellite bag. The resulting pc was left undisturbed for 60 minutes to promote disaggregation, and the platelets were then resuspended by gentle manual agitation.

Forty-eight pc were prepared. Mean (± sd) platelet yield from wb to prp was 78 (±13)% (range, 35 to 97%); yield from prp to pc was 94 (± 6)% (range, 75 to 100%); and overall yield (pc from wb) was 74(± 13)% (range, 36 to 91%). Mean pc platelet count was 8.0 (± 3.0) × 1010 platelets/pc (range, 2.3 to 13.4 × 1010 platelets/pc). The wbc content was 0.1 to 2.3 × 109 platelets/pc, representing 3 to 74% of wbc in the wb. Hematocrit was 0.1 to 26.2%. Results of bacterial and fungal culturing were negative.

The pc were irradiated (18 Gy) and transfused to 5 cross-matched dogs undergoing bone marrow transplantation that developed profound thrombocytopenia of up to 8 weeks’ duration. Transfusions were given over 5 to 15 minutes, using a latex-free transfusion set. Platelet count in recipients was monitored to confirm reduction in the degree of thrombocytopenia. Mean actual 24-hour post-pc transfusion platelet count was significantly (P < 0.0001) higher than mean expected 24-hour platelet count without pc transfusion. Recipients were closely observed for hemorrhage, which did not occur. Prevalence of transfusion reactions was 17%; signs were fever (5/46), urticaria (1/46), vomiting (1/46), and anaphylaxis (1/46).
Role of an intramammary device in protection against experimentally induced staphylococcal mastitis in ewes
Authors: Penadés José R. , Albizu Iñaki , Baselga Rafael , Marco Juan , Barberán Montserrat , Amorena Beatriz
Published: January 2024

An intramammary device (imd) was adapted for use in ewes; this device was made of abraded polyethylene material (1.7 mm in diameter, 47 mm long) and formed a 15-mm-diameter loop in the gland cistern. The imd was inserted in 1 gland in each of 43 ewes. A significant (P < 0.0001) increase in milk somatic cell count (scc) was observed in glands provided with an imd. This increase was attributable to an increase in neutrophil numbers and was observed during the first 12 weeks after insertion. The imd had a protective effect against experimentally induced staphylococcal mastitis (Staphylococcus aureus and S epidermidis), although different milk scc were required for protection from each bacterial species in most ewes (106 and 2 × 105 cells/ml, respectively). Histologic studies revealed that the imd induced local squamous metaplasia in the glandular part of the lactiferous sinus. Erythrocytes were found in milk from glands provided with an imd throughout the studied period (35 days of the 45-day lactation) and, in some cases, blood clots were observed during the first 2 weeks of lactation. Glands with imd also had lower milk production and quality at 30 and 32 days of lactation. Eight ewes with imd were studied throughout a subsequent lactation. Milk from the imd-containing glands had an increase in scc, as in the previous lactation period; did not contain blood clots or erythrocytes; and had normal composition (similar to that in glands without the imd).
Comparison of kittens fed queen's milk with those fed milk replacers
Authors: Remillard Rebecca L. , Pickett J. P. , Thatcher Craig D. , Davenport D. J.
Published: January 2024

Fifteen 2-week-old kittens were randomly assigned to 1 of 3 milk treatment groups as the sole source of nutrition for 4 weeks: queen's milk, commercially available kitten milk replacer (cmr), and an experimental milk replacer (exp). Kittens fed queen's milk suckled ad libitum, whereas cmr- and exp-fed kittens were tube-fed every 6 hours. Kittens were weaned at 6 weeks of age and were fed a feline growth diet ad libitum for an additional 4 weeks. Kittens were examined at 2, 4, 6, 8 and 10 weeks of age; the procedure included an ophthalmic examination and blood sample collection for cbc and serum biochemical and amino acid analyses. Kittens fed cmr and exp diets had weight gain greater than that for queen's milk-fed kittens. The kittens fed cmr, however, had diarrhea throughout most of the milk-feeding trial and developed diffuse anterior and posterior lens opacification and vacuolation at the posterior Y-sutures. The lens opacities noticed in the kittens during the milk treatments resolved to a residual perinuclear halo, and a few incipient cortical opacities were observed by the end of the growth diet-feeding period. Serum arginine concentration was significantly (P ≤ 0.05) lower in the cmr-fed kittens, but was not different during the growth diet-feeding period. We concluded that the exp diet supported normal growth in 2- to 6-week-old kittens; cmr supported normal kitten growth rate, but resulted in diarrhea and cataract formation; and serum amino acid data indicated that low arginine concentration may have been related to the cmr-induced cataract formation.
Use of survival analysis to compare cull rates between bovine leukemia virus seropositive and seronegative dairy cows
Authors: Pollari Franklin L. , DiGiacomo Ronald F. , Evermann James F.
Published: January 2024

Bovine leukemia virus (blv) infection and culling of cows in a commercial dairy herd were evaluated to determine whether a relation existed between the 2 factors. Cattle from the study population, a Holstein dairy herd consisting of approximately 400 milking cows, were tested for antibodies to blv, using the agar gel immunodiffusion test, semiannually for 2 years, annually for 2 years, and when cattle were culled. Complete records of blv test results were available for 849 (79%) of the 1, 078 cattle that had at least 1 test during the study period. Using the Cox hazard model, the cull hazard rates (culls/cow-months) were greater for blv seropositive cows than for seronegative cows > 36 months old. Hence, among older dairy cows, blv-infected cows were culled prematurely, compared with uninfected cows.
Pharmacokinetics and effects of repeated administration of phenylbutazone in neonatal calves
Authors: Semrad Susan Diane , McClure J Trenton , Sams Richard Alvin , Kaminski Lucille Marie
Published: January 2024

Age, species, and disease state may substantially alter the disposition and clearance of pharmacologic agents. This is particularly important when drugs with low therapeutic index are used in ill neonates. Pharmacokinetic variables for phenylbutazone were determined in 24- to 32-hour-old healthy and endotoxemic calves after iv administration of a single dose (5 mg/kg of body weight, iv). Elimination halflife was 207 and 168 hours, and clearance was 0.708 and 0.828 ml/kg/h in healthy and endotoxemic calves, respectively. Intravenous infusion of endotoxin at the dose (2 μg/kg over 4 hours) given did not significantly alter any of the calculated pharmacokinetic variables. Serum thromboxane B2 concentration was significantly (P = 0.05) suppressed for 3 hours after phenylbutazone administration in healthy calves and for 4 hours in endotoxin-challenged calves. Daily administration of phenylbutazone (10 mg/kg loading, then 5 mg/kg for 9 days) to healthy and endotoxemic calves failed to induce any lesions consistent with nonsteroidal anti-inflammatory drug toxicosis.
Effects of atropine on the arrhythmogenic dose of dobutamine in xylazine-thiamylal-halothane-anesthetized horses
Authors: Light Gwendolyn S. , Hellyer Peter W.
Published: January 2024

We investigated the influence of parasympathetic tone on the arrhythmogenic dose of dobutamine in horses premedicated with xylazine, anesthetized with guaifenesin and thiamylal, and maintained on halothane in oxygen. Six horses were used in 12 randomized trials. In each trial, after end-tidal halothane concentration was stabilized at 1.1% (1.25 times minimum alveolar concentration [mac]) in oxygen, either saline solution (0.02 ml/kg of body weight) or atropine (0.04 mg/kg) was administered iv. Five minutes later, dobutamine infusion was started at dosage of 2.5 μg/kg/min, iv. The dobutamine infusion was continued for 10 minutes, or until 4 or more premature ventricular complexes occurred within 15 seconds, or sustained narrow-complex tachyarrhythmia clearly not sinus in nature occurred. If the criteria for termination were not met, dobutamine infusion was increased by 2.5 μg/kg/min, after the hemodynamic variables had returned to baseline. The horses were allowed to recover, and were rested for at least 1 week before the second trial. The arrhythmogenic dose of dobutamine was calculated by multiplying the infusion rate by the elapsed time into infusion when arrhythmia occurred. There was significant difference between the arrhythmogenic dose of dobutamine (add) in saline-treated horses (mean ± sem, add = 105.6 ± 16.3 μg/kg) and atropimzed horses (add = 36.2 ± 8.7 μg/kg). There were no differences in the prearrhythmia or immediate postarrhythmia ventricular heart rate (hr) or systolic (sap), diastolic (dap), or mean (map) arterial pressures between treated and control groups. The change in hemodynamic variables from prearrhythmia to immediate postarrhythmia formation was not different between the 2 groups. Ventricular beats were clearly evident in 8 of the 12 arrhythmias meeting the criteria for establishing the add. These results indicate that atropine may lower the arrhythmogenic threshold for dobutamine in halothane-anesthetized horses.
Evaluation of occlusive dressings for management of full-thickness excisional wounds on the distal portion of the limbs of horses
Authors: Howard R. D. , Stasbak T. S. , Baxter G. M.
Published: January 2024

Two 2.5-cm2 full-thickness skin wounds were created surgically over the lateral aspect of the cannon bone of each limb of 6 horses (n = 48 wounds). Dressings evaluated were a nonadherent gauze pad (group 1); a synthetic semiocclusive dressing, (group 2); equine amnion (group 3); and a synthetic fully occlusive dressing (group 4). Wounds were assessed subjectively at each dressing change, and total wound area, area of granulation tissue, and area of epithelium in each wound were determined by computerized digital analysis of photographs of the wounds. Complete healing time (wound covered by epithelium) also was determined for each wound. Statistical comparisons were made, using Kruskal-Wallis analysis and a Mann-Whitney U test.

Median time to complete healing was: group 1, 53 days; group 2, 71 days; group 3, 63 days; and group 4, 113 days. Time to complete healing was significantly longer for wounds of group-4 horses than all other groups, and wounds of group-1 horses healed faster than did those of group-2 horses (P < 0.05). Wounds in group-4 horses required significantly (P ≤ 0.05) more excisions of granulation tissue (median, 11.5 times) than did those in group-1 (median, 3 5), group-2 (median, 5.5) or group-3 (median, 2.5) horses. Epithelial tissue was detected later in wounds of group-4 horses (median, 27 days) than in wounds of horses in groups 1, 2 or 3 (median, 17 days); however, this difference was not statistically significant. Significant differences were not found for percentage of healing attributable to wound contraction or epithelialization. Use of synthetic semiocclusive and fully occlusive dressings resulted in significantly (P < 0.05) prolonged healing and production of excess wound exudate, compared with control wounds. In this model, occlusion of wounds was not beneficial for healing of full-thickness skin wounds of the distal portion of the limbs of horses.
Effect of medetomidine on the pharmacokinetics of propofol in dogs
Authors: Hall Leslie W. , Lagerweij Evert , Nolan Andrea M. , Sear John W.
Published: January 2024

Pharmacokinetic variables of propofol were investigated in 6 mixed-breed dogs, and the effect of medetomidine (10 μg/kg of body weight) on these kinetics was investigated using a two-way crossover design. On 2 occasions, dogs received either a bolus dose of propofol sufficient to allow endotracheal intubation, followed by an infusion of propofol (0.4 mg/kg/min) for 120 minutes, or medetomidine (10 μg/kg, im), 15 minutes prior to induction of anesthesia as described, followed by infusion of propofol (0.2 mg/kg/min). Dogs given medetomidine received atipamezole (50 μg/kg, im) at the end of the 120-minute propofol infusion. Blood propofol concentration was measured, using high-performance liquid chromatography with fluorescence detection. Mean elimination half-life, blood clearance, mean residence time, and mean volume of distribution at steady state, were 486.2 minutes, 34.4 ml/kg/min, 301.8 minutes, and 6.04 L/kg, respectively, in the absence of medetomidine, and 136.9 minutes, 36.2 ml/ kg/min, 215.1 minutes, and 3.38 L/kg, respectively, in the presence of medetomidine. Mean time to walking without ataxia was 174 minutes in the nonpremedicated dogs (with a median blood propofol concentration of 2.2 μg/ml) and was 160 minutes in the premedicated dogs in which median blood propofol concentration was 1.03 μg/ml.
Estimation of glomerular filtration rate and evaluation of renal function in ferrets (Mustela putorius furo)
Authors: Esteves Maria I. , Marini Robert P. , Ryden Eva B. , Murphy James C. , Fox James G.
Published: January 2024

Three methods of determining glomerular filtration rate (gfr) were performed in adult ferrets, 9 months to 7 years old. Endogenous creatinine clearance was determined, using serum and urine creatinine values obtained during 24- and 48-hour collection periods from 27 ferrets housed in metabolic cages. Creatinine and radiolabeled inulin were administered to 12 female ferrets by constant iv infusion during isoflurane-induced anesthesia. Serial 20-minute urine collections, together with serum samples obtained at the midpoint of urine collection, provided measures for clearance calculations of these substances. Mean ± sd endogenous creatinine clearance in ferrets for metabolic cage collections was 2.50 ± 0.93 ml/min/ kg of body weight. There were no significant differences between the 24- and 48-hour clearance rates. Mean inulin clearance was 3.02 ± 1.78, and mean exogenous creatinine clearance was 3.32 ± 2.16 ml/ min/kg. Analysis of variance, using least-squared means adjustment, did not yield any significant differences between inulin and exogenous creatinine clearance rates. Exogenous creatinine clearance-to-inulin clearance ratio was 0.99 ± 0.46, and there was significant correlation between the 2 methods (r = 0.82, P = 0.0001). Significant body temperature effects on inulin or exogenous creatinine clearance were not found. Infused inulin clearance, the generally preferred method for gfr calculation in mammalian species, was significantly (P = 0.0069) higher in younger (3.65 ml/min/kg) vs older ferrets (2.29 ml/min/kg). Results of this study indicate that inulin clearance is an adequate measure of gfr in ferrets as it is in other species. Compared with inulin clearance, exogenous creatinine clearance also provides a reliable estimate of gfr in ferrets.
Analysis of physeal growth in dogs, using biplanar radiography
Authors: Conzemius Michael G. , Smith Gail K. , Brighton Carl T. , Marion Michael J. , Gregor Thomas P.
Published: January 2024

Biplanar radiography was used to study normal growth of the left and right radius in 5 Beagles and growth of the left radius alone in 15 additional Beagles. We explored the applicability of this radiographic method in veterinary medicine by measuring the contribution to total radius length from each growth plate. Spherical tantalum markers (0.5 mm) were embedded in the proximal epiphysis, diaphysis, and distal epiphysis of each dog's radius at 10 weeks of age. Simultaneous biplanar radiographic views were obtained every 4 weeks until skeletal maturity was documented. A three-dimensional coordinate system was constructed allowing for measurement of growth (in millimeters). Resolution of the measuring system was 0.074 mm. Mean ± sem length of the skeletally mature Beagle's radius, as measured from proximal epiphyseal bead to distal epiphyseal bead, was 95.33 ± 1.07 mm. The percentage of contribution to the total radius length from the proximal and distal growth plates was 36.76 and 64.73%, respectively, with 95% confidence interval of 2.29%. The percentage of contribution to radius length from the distal radial growth plate increased for each consecutive time segment, with the distal radial physis contributing 61.75% from 10 to 14 weeks of age and increasing to 70.22% from 22 to 26 weeks of age. Significant growth was not observed after 26 weeks of age. The period of most rapid growth was between 10 and 14 weeks of age.

Biplanar radiography was accurate and precise in quantifying the relative contribution of the proximal and distal growth plate to radius length in Beagles. The method is applicable in veterinary research or clinical medicine for monitoring of axial and angular growth: physiologic, iatrogenic, or pathologic.
Assessment of vertebral canal diameter and bony malformations of the cervical part of the spine in horses with cervical stenotic myelopathy
Authors: Moore Bonnie Rush , Reed Stephen M. , Biller David S. , Kohn Catherine W. , Weisbrode Steven E.
Published: January 2024

Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (msd) values and application of the established msd values for diagnosis of cervical stenotic myelopathy (csm). Variability in msd determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The msd of the vertebral canal was determined in 50 horses with csm and 50 control horses, using a radiopaque marker method for correction of magnification. In addition, a ratio of the absolute msd to the sagittal width of the vertebral body and a ratio of the absolute msd to the length of the vertebral body were determined in 100 csm-affected and 100 control horses. Response operating characteristic curve analysis of each method determined that the sagittal ratio method of canal diameter assessment provided the most accurate interpretation of cervical radiographs for diagnosis of csm, with sensitivity and specificity of ≥ 89% at each vertebral site. The accuracy of the ratio method, without consideration of bony malformation, supports the importance, and perhaps prerequisite, of generalized vertebral canal stenosis in the pathogenesis of csm. Subjective evaluation of bony malformations from cervical radiographs of 100 csm-affected horses and 100 control horses indicated that csm-affected horses have more severe bony malformation than do control horses. However, moderate to marked degenerative joint disease of the articular processes was frequently observed in control horses. Subjective evaluation of bony malformation does not distinguish between csm-affected and unaffected horses.
Determination of calcium, phosphorus, and magnesium values in rib bones from clinically normal cattle
Authors: Beighle D. E. , Boyazoglu P. A , Hemken R. W. , Serumaga-Zake P. A.
Published: January 2024

Mean phosphorus (P) content in bovine rib bone was 102.9, 108.3, and 182.7 mg/g of bone on fresh, dry, and ash weight bases, respectively. Values for calcium (Ca) were 194.3, 203.7, and 344.6 mg/g, respectively, and for magnesium (Mg) were 5.3, 5.5, and 9.4 mg/g, respectively. Mean percentage of ash in rib bone was 59.12%. Expected concentrations of Ca, P, and Mg were determined on fresh, dry, and ash weight bases and for 3 age groups, 3 breeds, and bulls, females, and steers. On an ash weight basis, cattle 6 to 18 months old had 185.74 mg of P/g, 372.52 mg of Ca/g, and 12.37 mg of Mg/g. Those 19 to 36 months old had 182.02 mg of P/g, 322.35 mg of P/g, and 8.09 mg of Mg/g. Those > 36 months old had 174.80 mg of P/g, 340.36 mg of Ca/g, and 6.62 mg of Mg/g. Steers had 183.93 mg of P/g, 352.73 mg of Ca/g, and 10.15 mg of Mg/g. Females had 178.47 mg of P/g, 320.28 mg of Ca/g, and 6.5 mg of Mg/g. Males had 176.15 mg of P/g, all on an ash weight basis. Dairy breeds were found to have 186.08 mg of P/g, 351.25 mg of Ca/g, and 10.47 mg of Mg/g. Cattle of mixed breeding had 177.42 mg of P/g, 341.28 mg of Ca/g, and 6.54 mg of Mg/g. The Africander breed of beef cattle had 167.07 mg of P/g, all on an ash weight basis.
Plasma concentrations of immunoreactive proopiomelanocortin peptides and cortisol in clinically normal cats
Authors: Peterson Mark E. , Kemppainen Robert J. , Orth David N.
Published: January 2024

We measured immunoreactive (ir) plasma concentrations of the proopiomelanocortin (pomc)-derived peptides (adrenocorticotropic hormone [actch]; β-endorphin/β-lipotropin [βend/βlph]; and α-melanocyte stimulating hormone [αmsh]) and of cortisol in 100 clinically normal cats. Median plasma concentration of ir-acth was 2.7 pmol/L (range, ≤ 1.1 to 22 pmol/L), of βend/βlph was 28 pmol/L (range, 3.8 to 130 pmol/L), of αmsh was 36 pmol/L (range, ≤ 3.6 to 200 pmol/L), and of cortisol was 35 nmol/L (range, 5 to 140 nmol/L). Plasma concentrations of IR-ACTH, αmsh, and βend/βlph were at or below the assay sensitivity in 34, 3, and 0% of the cats, respectively. We did not detect a correlation between plasma concentrations of ir-acth and βend/βlph (r = 0.23) or between plasma concentrations of ir-acth and αmsh (r = 0.19). However, there was a significant (P < 0.001) correlation between plasma concentrations of ir-βend/βlph and αmsh (r = 0.81). There was not a significant correlation between plasma concentration of cortisol and plasma concentration of any of the ir-pomc peptides. High plasma concentrations of ir-αmsh and βend, pomc peptides secreted predominantly by melanotrophs in other species, indicate that clinically normal cats have an actively secreting pars intermedia. Although the βend/βlph assay used in this study measures the pars distalis-derived peptide β-lph, as well as βend itself, over 95% of the ir-βend/βlph activity in feline plasma containing high concentrations of αmsh, but low concentrations of ir-acth, was found to coelute with human βend on gel filtration chromatography. In contrast to the high plasma concentrations of ir-αmsh and βend/βlph, many cats had low to undetectable concentrations of ir-acth, a peptide secreted predominantly by pars distalis corticotrophs. The pattern of plasma pomc peptide concentrations found in cats is similar to that reported in rats, but is markedly different from that reported in dogs, in which the secretion of pars intermedia pomc peptides is normally low.
Effects of low and high fractions of inspired oxygen on ventilation in ducks anesthetized with isoflurane
Authors: Seaman Grant C. , Ludders John W. , Erb Hollis N. , Gleed Robin D.
Published: January 2024

High fractions of inspired oxygen are commonly used during general anesthesia in birds. Observations in ducks anesthetized with halothane or pentobarbital indicated that high fractions of inspired oxygen depress ventilation. The purpose of this study was to test the hypothesis that ducks hypoventilate when breathing high fractions of inspired oxygen, compared with the same ducks breathing low fractions of inspired oxygen.

Respiratory variables were recorded in 7 ducks anesthetized with 1.4% isoflurane in oxygen. Four concentrations of oxygen (21, 40, 70, and > 90%) were used for each duck. Respiratory rate decreased as the fraction of inspired oxygen increased, but not significantly. There was a significant decrease in tidal volume as Paco2 increased. Hyperoxia was observed to contribute to hypoventilation in ducks anesthetized with isoflurane in oxygen.
Identification of subspecies- and serotype 1-specific epitopes on the 80- to 90-kilodalton protein region of Chlamydia psittaci that may be useful for diagnosis of Chlamydial induced abortion
Authors: Souriau Armel , Salinas Jesus , De Sa Carlos , Layachi Khalid , Rodolakis Annie
Published: January 2024

Genus-, subspecies-, and serotype 1-specific antigens of Chlamydia psittaci were characterized by immunoblot analysis, using monoclonal antibodies that recognize 2 C psittaci strains: AB7 isolated from an ewe that had aborted, and iBl isolated from feces of a healthy ewe. Genus-specific epitopes were detected on lipopolysaccharide, on a 47-kd protein, and on a 27- to 30-kd doublet. Subspecies-specific epitopes were located on a 30-kd protein, and a 80- to 90-kd protein region was identified, which bore subspecies- and serotype l-specific epitopes. These 80- to 90-kd proteins were highly reactive with serum from ewes that had aborted and could be a useful antigen for diagnosis of Chlamydial induced abortion of ruminants.
Effects of experimentally induced hypothyroidism on the eye and ocular adnexa of dogs
Authors: Miller Paul E. , Paneiera David L.
Published: January 2024

Schirmer tear test (stt), intraocular pressure (iop) measurement, slit-lamp biomicroscopy, and indirect ophthalmoscopy were performed on 8 dogs with 131I-induced hypothyroidism and 4 euthyroid control dogs at weeks 0, 9, 13, 17, immediately prior to treatment with levothyroxine, after 5 weeks of levothyroxine administration (0.022 mg/kg of body weight, po, q 12 h), and at euthanasia 7 weeks after discontinuation of replacement therapy. Although the control group had higher baseline stt values than the hypothyroid group after randomization of dogs into the 2 groups (P < 0.01), stt values remained unchanged from their respective baseline values at all time intervals for both groups. Hypothyroid and control dogs had significant (P < 0.05) reduction in iop from baseline values at all subsequent time points, but differences were not observed when hypothroid dogs were compared with controls. Goblet cell indices determined from biopsy samples of the inferiornasal conjunctival fornix obtained before induction of hypothyroidism (baseline), immediately prior to and at conclusion of levothyroxine therapy, and at euthanasia were not significantly different when values for hypothyroid dogs were compared with their own baseline values or with values for control dogs. Histologic examination of the globes and adnexa at euthanasia also failed to indicate consistent qualitative differences between hypothyroid and control dogs. Marked reduction in serum thyroid hormone concentrations had little effect on the eye and ocular adnexa over the course of the study.
Adrenocorticotropic hormone and cortisol concentrations after corticotropin-releasing hormone stimulation testing in cats administered methylprednisolone
Authors: Crager Cynthia Susan , Dillon Allen Ray , Kemppainen Robert James , Brewer William Grafton , Angarano Donna Walton
Published: January 2024

The hypothalamic-pituitary-adrenocortical (hpa) axis was studied in 8 healthy cats after administration of supraphysiologic doses of methylprednisolone (mp). Ovine corticotropin-releasing hormone (oCHR) administration increased cortisol and adrenocorticotropic hormone (acth) concentrations. Significant (P < 0.05) suppression of cortisol and a trend toward suppression of acth was observed after 1 week of mp administration. The hpa axis quickly recovered from suppressive effects of mp 1 week after administration of the steroid was discontinued. Side effects of ocrh administration were minimal in 7 cats; however, 1 cat had a severe hypotensive reaction. Clinical abnormalities were not associated with mp administration.

The hpa axis was suppressed by supraphysiologic doses of mp in all treated cats that lacked clinical signs consistent with iatrogenic hpa axis suppression. Despite the relatively active pars intermedia in cats, compared with human beings and dogs, feedback of mp on the hpa axis resulted in similar trends in ocrh-stimulated acth and cortisol concentrations as observed in human beings and dogs. Lack of consistent correlation between acth and cortisol concentrations was observed in 3 cats and possibly was related to the active pars intermedia in the cat.
Use of hepatobiliary scintigraphy in clinically normal cats
Authors: Newell Susan M. , Selcer Barbara A. , Roberts Royce E. , Mahaffey Mary B. , Cornelius Larry M. , Mahaffey Edward , Brown John
Published: January 2024

Hepatobiliary scintigraphy provides a noninvasive assessment of hepatobiliary structure and function, and has been used extensively in people. Hepatocellular measurements determined in the cats of this study include cardiac washout (≤ 2 minutes) and time of maximal hepatic activity (≤ 5 minutes) and hepatic washout (≤ 30 minutes). The gallbladder response to synthetic cholecystokinin was determined to be ≤ 3 minutes. Additional measurements also were identified. Potential use of hepatobiliary scintigraphy in feline medicine is discussed.
Inhibition of complement-mediated killing of Brucella abortus by fluid-phase immunoglobulins
Authors: Hoffmann Edward Marker , Kellogg William Lee , Houle Jeri Joan
Published: January 2024

Bovine immunoglobulin preparations from normal serum and from sera containing antibodies against Brucella abortus interfered with the brucellacidal action of bovine serum, whereas unfractionated normal serum and antisera were not inhibitory. The inhibitory property of immunoglobulin appeared to be attributable to some anticomplementary property because it also interfered with serum-mediated hemolysis of antibody-coated erythrocytes. The supernatant phase obtained after ultracentrifugation of bovine anti-B abortus immunoglobulin did not inhibit brucellacidal activity of normal bovine serum. Results of this study indicate that bovine anti-B abortus immunoglobulin preparations contain microaggregates of protein that can inhibit the ability of bovine serum to kill B abortus. The most likely mechanism is nonspecific activation of complement by microaggregated immunoglobulin, which consumes complement and makes it unavailable for bactericidal activity.
Pharmacokinetics of single-dose administration of tinidazole in unweaned calves
Authors: Pyörälä Satu , Soback Stefan , Rainio Vesa , Silvennoinen Paula , Nokelainen Marja
Published: January 2024

In a crossover trial, 7 healthy, 7- to 29-day-old, unweaned Finnish Ayrshire calves were given a single dose of 20 mg of tinidazole/kg of body weight, iv, and a single dose of 25 mg of tinidazole/kg orally. Blood samples were collected serially, and serum concentration of tinidazole was measured by use of high-performance liquid chromatography.

Serum concentration vs time data were analyzed by use of the statistical moment theory. Terminal half-life was 394 minutes after iv administration and 524 minutes (harmonic mean) after oral administration. The corresponding system moment mean residence times were 542 ± 61.8 minutes and 812 ± 117 minutes (arithmetic mean ± sd), respectively. Estimated volume of distribution at steady state and total body clearance were 0.74 ± 0.05 L/kg and 1.37 ± 0.13 ml/min/kg, respectively. Tinidazole was rapidly and totally absorbed from the gastrointestinal tract. Mean absorption time was 270 ± 160 minutes, and the observed peak serum concentration was detected at 240 minutes. Bioavailability was 99.5 ± 3.9%.
Persistence of immunity to toxoplasmosis in pigs vaccinated with a nonpersistent strain of Toxoplasma gondii
Authors: Dubey J. P. , Baker D. G. , Davis S. W. , Urban J. F. , Shen S. K.
Published: January 2024

Persistence of the vaccine RH strain of Toxoplasma gondii was studied by bioassay and histologically in 14 pigs. Pigs were euthanatized 2, 4, 7, 8, 14, 15, 21, 29, 36, 42, 52, 57, and 76 days after im inoculation with 100,000 T gondii tachyzoites. Viable T gondii tachyzoites derived from the RH strain were isolated by bioassay in mice inoculated with tissues of pigs euthanatized up to 14 days after vaccination. Except for fever, pigs vaccinated im with the RH strain remained clinically normal. Two other pigs inoculated iv with 100,000 T gondii tachyzoites of the RH strain became ill, and 1 pig was comatose by 4 days after inoculation. These findings indicate that route of inoculation may influence the response of pigs to T gondii. To evaluate protective immunity in pigs vaccinated with the RH strain, 16 age-matched pigs were allotted to 4 groups (A-D) of 4 pigs each. Eight pigs (groups A and C) were vaccinated im with 100,000 RH strain tachyzoites and 8 pigs (groups B and D) were nonvaccinated controls. Pigs of groups A and C were challenge-inoculated orally with a lethal dose of T gondii oocysts (100,000 oocysts) 81 days after vaccination, pigs of groups B and D were inoculated similarly 220 days after vaccination. The concentration of T gondii at 3 days after challenge inoculationl of pigs vaccinated 81 days earlier was reduced 100,000-fold in mesenteric lymph nodes, compared with that in a nonvaccinated pig euthanatized at 3 days after challenge inoculation. Another nonvaccinated pig became comatose and had to be euthanatized at 7 days after challenge inoculation; numerous tachyzoites were in its mesenteric lymph nodes, intestines, and liver. The vaccinated pigs generally remained clinically normal after challenge inoculation with oocysts. Toxoplasma gondii was not isolated by bioassays from tissues of 5 of 8 vaccinated pigs, but was recovered from all nonvaccinated pigs. Results indicate that protective immunity persisted in pigs for at least 7 months after vaccination with the nonpersistent RH strain of T gondii.
Efficacy of fenbendazole against giardiasis in dogs
Authors: Barr Stephen C. , Bowman Dwight D. , Heller Ruth L.
Published: January 2024

Efficacy of fenbendazole at 2 dosages for treating naturally acquired giardiasis in dogs was assessed. Giardia cysts were not detected in the feces of 6 of 6 group-1 dogs (as determined by use of the zinc sulfate concentration technique) after fenbendazole treatment (50 mg/kg of body weight, po, q 24 h, for 3 doses). Cysts were not detected in the feces of 6 of 6 group-2 dogs after fenbendazole treatment (50 mg/ kg of body weight, po, q 8 h, for 3 days). However, cysts were not detected in the feces of only 1 of 6 group-3 (nontreated control) dogs. Signs of toxicosis were not observed in any dog. These results indicate that the current label dosage (for the treatment of Toxocara canis, Toxascarisleonina, Ancylostoma canmum, Uncinaria stenocephala, Trichuris vulpis, and Taenia pisiformis, but not Giardia spp) of fenbendazole (50 mg/kg, po, q 24 h, for 3 doses) is also effective for treating giardiasis in dogs.
Toxoplasma gondii-specific antibodies in the aqueous humor of cats with toxoplasmosis
Authors: Chavkin M. J. , Lappin M. R. , Powell C. C. , Cooper C. M. , Muñana K. R. , Howard L. H.
Published: January 2024

We decided to determine whether Toxoplasma gondii-specific IgM or IgG is produced locally or is deposited in the aqueous humor of T gondii-naive cats after primary or secondary inoculation with T gondii. Cats were orally inoculated with T gondii tissue cysts during weeks 0 and 36. Aqueous humor and serum Tgondii-specific IgM and IgG were measured, using ELISA, during weeks 0, 2, 4, 6, 8, 12, 16, 20, 26, 34, 38, 40, 42, 44, 48, 56, 62, 66, and 72 after primary oral inoculation. Total immunoglobulin-based Goldmann-Witmer coefficients were calculated to verify intraocular antibody production.

Toxoplasmagondii-specific IgM was not detected in the aqueous humor of any cat. Data indicate that cats have transient local production of T gondii-specific IgG in the aqueous humor after primary and secondary oral inoculations with T gondii tissue cysts.

The intraocular immune response to systemic T gondii infection may signal ocular recruitment of antigen-specific lymphocytes that function independently from the general humoral response to T gondii infection. Cautious interpretation of results that suggest intraocular production of Tgondii-specific IgG in cats with uveitis is warranted.
Experimental induction of hepatic lipidosis in cats
Authors: Biourge Vincent C. , Groff Joseph M. , Munn Robert J. , Kirk Claudia A. , Nyland Thomas G. , Madeiros Victoria A. , Morris James G. , Rogers Quinton R.
Published: January 2024

The effect of long-term voluntary fasting on hematologic variables, biochemical profiles, and liver histologic findings was assessed in 15 obese cats (> 40% overweight). Clinical signs and laboratory results consistent with hepatic lipidosis were observed in 12 of 15 cats after 5 to 7 weeks of fasting, and were associated with 30 to 35% reduction of initial body weight. Histologic examination of successive liver biopsy specimens revealed that obesity was not associated with liver parenchymal lipid accumulation, but that fasting resulted in lipidosis in all 15 cats. The long-term fast was associated with an early (after 2 to 4 weeks of fasting) and significant (P< 0.05) reduction in serum urea, glucose, and albumin concentrations, and RBC mass. Fasting for 5 to 7 weeks was associated with a significant (P< 0.05) increase in hepatic-associated enzyme activities and in total and direct serum bilirubin concentrations. Significant (P< 0.05) changes in serum alkaline phosphatase developed as early as 3 weeks before the onset of hyper-bilirubinemia. Except for development of hepatic lipidosis, cats appeared to tolerate the fast without other adverse effect. This study confirmed that longterm fasting may induce clinical hepatic lipidosis in obese cats. Fasting appears to induce a syndrome of hepatic lipidosis that is indistinguishable from feline idiopathic hepatic lipidosis and may be an appropriate model to study the pathophysiologic features and treatment of hepatic lipidosis.
Polymerase chain reaction for detection of Borrelia coriaceae, putative agent of epizootic bovine abortion
Authors: Zingg Barbara C. , LeFebvre Rance B.
Published: January 2024

The nucleotide sequence of a chromosomally encoded antigen-expressing gene of Borrelia coriaceae was determined and used as a target for the polymerase chain reaction (PCR). Two primer sets were designed specifying the amplification of 269- and 701-bp dna fragments. Primer set I, producing the short amplicon, was tenfold more sensitive than primer set II. As little as 10 fg of purified B coriaceae dna could consistently be detected. The pcr assays, containing controlled numbers of whole spirochetes, allowed detectable amplification of 2 to 10 organisms. An internal, nonradioactively labeled gene-specific probe verified specificity of the pcr amplicons. Neither primer set cross-reacted with other related spirochetes. This pcr assay was adapted and found suitable for identification of B coriaceae in biological samples, such as blood and thymus. Evidence for presence of B coriaceae in biological samples was not found in tissue samples obtained from experimentally infected cows and their fetuses. These data failed to establish a definite association between B coriaceae and epizootic bovine abortion.