bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of acute infection with noncytopathic or cytopathic bovine viral diarrhea virus isolates on bovine platelets
Authors: Bezek David M. , Gröhn Yrjö T. , Dubovi Edward J.
Published: January 2024

A total of 21 calves were inoculated IV with 1 of the following isolates of bovine viral diarrhea virus (BVDV); CD87 (n = 10), NY-1 (n = 3), NADL (n = 5), or were sham-inoculated with virus-free medium (n = 3). Subsequent to inoculation, platelet counts were monitored to detect differences between noncytopathic (CD87, NY-1) and cytopathic (NADL) isolates in their ability to induce thrombocytopenia. Platelet count decrease throughout infection was statistically analyzed by comparing the slope of the line drawn from the count on the day of infection to the lowest count achieved by that calf. Significant difference was observed in the CD87-inoculated calves and in the NY-1-inoculated calves, compared with those of the same control group. Significant difference was not observed in the slope of platelet count decrease between the cytopathic NADL-infected calves and control-group calves. The data indicate that noncytopathic BVDV isolates may more easily induce thrombocytopenia than do cytopathic isolates in immune-naive, immunocompetent calves; acute infection with 1 cytopathic BVDV isolate (NADL) did not induce thrombocytopenia. In addition, although each calf seroconverted, virus was rarely isolated from mononuclear cells obtained from calves with cytopathic infections. At some point after infection, virus was always isolated from each of the calves undergoing noncytopathic infections, and occasionally, transient association of noncytopathic BVDV antigen with platelets was observed during these infections.
Evaluation of immunoreactivity of normal tissues from dogs, using monoclonal antibody B72.3
Authors: Clemo F. A. S. , DeNicola D. B. , Zimmermann J. L.
Published: January 2024

Monoclonal antibody (MAB) B72.3, which recognizes human tumor-associated glycoprotein-72, has immunoreactivity for malignant epithelial neoplasms in human beings and dogs. To further characterize the range of immunoreactivity of MAB B72.3 in canine tissues, MAB B72.3 and 2 other tumor-associated glycoprotein-72 antibodies (MAB CC49 and CC83) were tested against a wide spectrum of normal tissues from dogs. Immunoreactivity was detected, using an avidin-biotin-complex immunoperoxidase method. Monoclonal antibody B72.3 did not stain most types of normal canine tissues, but various types of epithelial cells within the gastrointestinal and respiratory tract mucosae, salivary gland, esophagus, epididymis, uterus, thymus, hair follicle, and apocrine glands of the anal sac had variable staining with MAB B72.3. A similar range of immunoreactivity in comparable types of normal tissues was seen for MAB CC49 and CC83; however, MAB CC49, but not MAB B72.3 and CC83, stained the endothelium of capillaries and small vessels in most normal tissues. Staining of frozen and paraffin-embedded tissues was similar. In conclusion, we found that MAB B72.3, CC49, and CC83 had selected immunoreactivity for specific types of normal canine epithelial cells, especially those involved with mucin production.
Mechanical properties of long bones in dogs
Authors: Markel Mark D. , Sielman Emily , Rapoff Andrew J. , Kohles Sean S.
Published: January 2024

Basic research in canine mechanics must be performed to better understand the forces and moments the appendicular skeleton must withstand. This type of research may allow surgeons to make substantial advances in total joint replacement and fracture fixation design and may enhance our understanding of bone remodeling and fracture occurrence in relation to exercise and trauma. In our study, craniocaudal bending stiffness, mediolateral bending stiffness, axial compressive stiffness, and torsional stiffness of the humerus, femur, radius, and tibia of dogs was determined, using nondestructive bending, compression, and torsional tests. Entire diaphyseal and middiaphyseal properties of these long bones were evaluated. Bones also were tested to failure in torsion to quantify the failure properties of these long bones. Left to right variability was examined to validate the use of contralateral limbs as the control condition for experimental studies. There were no significant right to left differences in entire diaphyseal mechanical properties for any of the long bones, except for compressive stiffness of femurs. Homotypic differences in entire diaphyseal mechanical properties, if present, ranged from 8.0 to 35% for the 4 long bones (power = 0.8). For middiaphyseal mechanical properties, there were no significant right to left differences in the 4 long bones, except for craniocaudal bending stiffness of tibias. The homotypic differences in middiaphyseal mechanical properties, if present, ranged from 7.2 to 62% for the 4 long bones (power = 0.8). In all bones and loading modes, middiaphyseal stiffness was greater than entire diaphyseal stiffness (P < 0.0001). In torsional energy to failure and maximal torsional displacement at failure, entire diaphyseal properties were significantly (P < 0.0001) higher than middiaphyseal properties. In axial compression, there were no entire diaphyseal or middiaphyseal mechanical property differences among the 4 bones. In craniocaudal bending, humeruses were significantly (P < 0.05) more stiff than the other 3 bones in the entire diaphysis, and were more stiff than radiuses and tibias in the middiaphysis. In mediolateral and craniolateral bending and in torsion, radiuses were less stiff, in the entire diaphysis and in the middiaphysis, than were the other 3 bones (P < 0.05). In torsion, there were no significant differences in energy to failure or in maximal displacement at failure among the 4 bones, either in the entire diaphysis or middiaphysis.
Biological half-life of aerosolized 99mTc-diethylenetriaminepentaacetate in various lung regions of clinically normal Beagles
Authors: Steyn Phillip F. , Gillette Sharon , Gillette Edward L.
Published: January 2024

The biological half-life (TB) of aerosolized 99mTc-diethylenetriaminepentaacetate was determined in 14 lung regions of 18 clinically normal Beagles. Three groups of lung regions or volumes were identified on the basis of significantly (P < 0.05) different TB. Group A (mean ± SD TB, 82 ± 21 minutes) included the transversely oriented cranial and caudal nonperihilar regions. Group B (mean ± SD, 61 ± 15 minutes) represented all sagittally oriented lung regions and the entire lung field. Group C (mean ± SD, 49 ± 11 minutes) included the transversely oriented cranial and caudal perihilar regions. Clearance of 99mTc-diethylenetriaminepentaacetate is considered a function of transepithelial transport into the blood, as well as bronchial transport via the mucociliary transport mechanism.
Prolonged gestation, decreased triiodothyronine concentration, and thyroid gland histomorphologic features in newborn foals of mares grazing Acremonion coenophialum-infected fescue
Authors: Boosinger Timothy R. , Brendemuehl James P. , Bransby David L. , Wright James C. , Kemppainen Robert J. , Kee David D.
Published: January 2024

Newborn foals of mares grazing on Acremonium coenophialum-infected fescue pasture throughout gestation or from gestation day 300 to parturition had increased gestation duration and decreased serum triiodothyronine concentration. Pregnant mares were allotted to 4 treatments: grazing continuously on endophyte-free (E−) fescue, grazing continuously on endophyte-infected (E+) fescue, grazing on E+ fescue from gestation day 300 to parturition, and grazing on E+ fescue from conception to gestation day 300. Morphometric studies indicated that foals born to mares exposed to endophyte late in gestation had large, distended thyroid follicles lined by flat cuboidal epithelial cells. Mean triiodothyronine concentration in foals exposed to endophyte (395.2 ng/dl) was decreased (P < 0.01), compared with mean values in control foals (778.0 ng/dl). Thyroxine and reverse triiodothyronine concentrations were not significantly different among groups. Foal organ weight as a percentage of foal body weight was not significantly different among experimental groups.
Parathyroid hormone-related protein and calcium homeostasis during the periparturient period of dairy cows
Authors: Kocabagli Nese , Riond Jean-Luc , Spichiger Ursula E. , Wanner Marcel
Published: January 2024

Plasma and milk concentrations of parathyroid hormone-related protein (PTHrP) at various stages of pregnancy and lactation were determined in thirtynine 3- to 16-year-old Brown Swiss and Red Holstein × Simmental dairy cows originating from 4 herds. Eighteen of the cows were separated into 2 groups: low-parity (lp, n = 8) cows if they were in their first or second pregnancy and high-parity (hp, n = 10) cows if they were in their third or greater pregnancy. Blood samples were collected from each cow on 1 occasion, 15 to 5 days before calving, and blood and milk samples were collected daily during 6 days after calving. Serum total and ionized calcium (Catot and Ca2+, respectively) and milk Catot concentrations were also quantified.

A transient postpartum decrease of serum Catot and Ca2+ concentrations was observed, whereas milk Catot concentration was constant. Plasma concentration of PTHrP was detected in 11 of 21 cows by use of an immunoradiometric assay (range, 0.45 to 1.82 pmol/L). Daily mean (± sd) colostrum and milk PTHrP concentrations ranged from 3.25 (± 3.23) to 4.69 (± 1.36) nmol/L in lp cows and 2.74 (± 0.5) to 5.95 (± 0.33) nmol/L in hp cows. In all cows of the hp group and most cows of the lp group, milk PTHrP concentration was highest in the day-1 sample. Milk PTHrP concentration correlated positively with milk Catot concentration in hp cows (r = 0.5959, P < 0.0001). In contrast, there was a negative relation between milk PTHrP and milk Catot concentrations in lp cows (r = −0.3285, P < 0.02). Milk PTHrP concentration was not correlated with serum Ca2+ concentration at postpartum days 5 and 6, when serum Catot and Ca2+ concentrations had returned to prepartum values. Because correlation did not exist between the lowest serum Ca2+ values and milk PTHrP concentration of the corresponding day, milk PTHrP concentration most likely is not a major determinant of Ca transport into milk and the PTHrP released into the blood stream is most likely not a major determinant of the endocrine regulation of serum Catot and Ca2+.

Thus, although it is involved, PTHrP is not a major factor in the integrative endocrine, paracrine, and autocrine regulation of Ca homeostasis in lactating cows. It is hypothesized that Ca may be actively transported from blood into milk with a process modulated by PTHrP. These data suggest that PTHrP produced by the mammary gland is most likely not involved in the pathogenesis of parturient paresis (milk fever) in dairy cows.
Comparison of volume-conducted far-field short-latency glossopharyngeal nerve evoked potentials recorded from the scalp with similarly obtained near-field potentials from the solitary nucleus in dogs
Authors: Venker-van Haagen Anjop J. , van den Brom Walter E. , Peeters Marijke E. , Barbas-Henry Heleen A.
Published: January 2024

In 11 dogs, potentials recorded from the scalp and from the solitary nucleus after stimulation of the glossopharyngeal nerve were compared. The far-field potentials recorded from the scalp consisted of negativity, with peak latency of 2.10 to 3.45 milliseconds (mean, 2.93 milliseconds), followed by positivity, with peak latency of 3.20 to 5.95 milliseconds (mean, 4.86 milliseconds) and duration of 4.65 to 6.95 milliseconds (mean, 5.70 milliseconds). The near-field potentials recorded from the solitary nucleus consisted of positivity, with peak latency of 2.15 to 2.70 milliseconds (mean, 2.45 milliseconds), followed by negativity, with peak latency of 4.05 to 5.05 milliseconds (mean, 4.39 milliseconds) and duration of 4.45 to 5.80 milliseconds (mean, 5.21 milliseconds). Comparison of the far-field potentials (n = 10) with the near-field potentials (n = 5) indicated that polarity of the waves was reversed and that the first peak’s latency was slightly (approx 0.5 milliseconds) longer in the scalp-recorded far-field potentials. Neither the difference in latency of the second peak nor the difference in its duration, measured from the onset of the potentials to the return to the baseline of the activity, was significant. The results strongly suggest that the response in the solitary nucleus evoked by electrical stimulation of the glossopharyngeal nerve is the source of at least part of the scalp-recorded responses to stimulation of the same nerve. The scalp-recorded far-field potentials could, therefore, be characterized as volume conducted from the evoked response in the solitary nucleus.
Body weight, heart weight, and heart-to-body weight ratio in Greyhounds
Authors: Schoning Polly , Erickson Howard , Milliken George A.
Published: January 2024

Heart and body weights were obtained from 230 Greyhounds during necropsy. Sex and age were recorded for each Greyhound. Twenty-nine racing and 21 nonracing Greyhounds among the 230 dogs were compared. Heart-to-body weight ratio was calculated. Statistical analysis was done to determine the effects of age, sex, and racing on heart and body weights and heart-to-body weight ratio.

In adult Greyhounds, mean ± SD body weight was 28.4 ± 3.1 and 31.5 ± 2.8 kg, heart weight was 355.6 ± 52.8 and 381.4 ± 50.8 g, and heart-to-body weight ratio was 1.3 ± 0.2 and 1.2 ± 0.2% for females and males, respectively. Heart and body weights were significantly different between sex and age groups and among nonracing and racing males. However, heart-to-body weight ratio was not significantly different among age, sex, or racing groups.
Eicosanoid concentrations in digital venous blood from horses with chronic laminitis
Authors: Owens Jane G. , Kamerling Steven G. , Keowen Michael L.
Published: January 2024

The eicosanoids are a family of lipid-derived autocoids that are released in response to a variety of physical and hormonal stimuli. In this study, prostaglandin E2 (pge2) and leukotriene B4 (ltb4) were measured in the digital veins of clinically normal horses and horses with chronic laminitis to determine whether these arachidonic acid metabolites have a role in mediating signs of hoof pain and lesions associated with chronic laminitis. Horses were evaluated at rest and after a brief exercise period, to determine whether eicosanoids are released into the circulation after mild concussion. Digital vein eicosanoid concentrations in horses with signs of hoof pain attributable to chronic laminitis were not different than those in clinically normal horses. There was no difference in resting and postexercise pge2 or ltb4 concentrations. Mean digital vein pge2 concentration for the 2 groups was 187.18 pg/ml, whereas mean digital vein ltb4 concentration for the 2 groups was 74.71 pg/ml. These data do not support the hypothesis that pge2 and ltb4 have a role in mediating the signs of pain and pathologic features of chronic laminitis.
Effect of xylazine, cisapride, and naloxone on myoelectric activity of the ileocecocolic area in cows
Authors: Steiner Adrian , Roussel Allen J. , Iselin Urs
Published: January 2024

The effect of xylazine, cisapride, and naloxone on myoelectric activity of the ileum, cecum, and proximal loop of the ascending colon (plac) was determined in 4 healthy Jersey cows implanted with 8 pairs of bipolar electrodes. A 4 × 4 Latin square design was used. The treatments included xylazine (0.04 mg/kg of body weight), cisapride (0.08 mg/kg), naloxone (0.05 mg/kg), and 0.9% sodium chloride solution (20 ml). All treatments were administered IV during early phase I of the migrating myoelectric complex in the ileum. Myoelectric activity was recorded for 4 hours after treatment, and data were analyzed for each hour separately.

Xylazine significantly (P < 0.05) increased the duration of phase I of the first migrating myoelectric complex in the ileum to 220.72 ± 26.89 minutes, compared with 30.91 ± 10.11 minutes after administration of 0.9% sodium chloride solution. The number of cecocolic spikes per minute per electrode and the duration of cecocolic spike activity (percentage of recording time) were significantly (P < 0.05) decreased for the first 3 hours, and the number of propagated spike sequences in the cecum and PLAC was significantly (P < 0.05) decreased for the first 2 hours after administration of xylazine. Significant difference was not found between control and either cisapride or naloxone treatment of healthy cows. However, during hour 1 after treatment with cisapride, number of spikes per minute, duration of spike activity, and number of propagated spike sequences were highest, compared with the other treatments.

It was concluded that naloxone at the dosage used in this study was not suitable for medical treatment of cecal dilatation in cattle, when hypomotility of the cecum and PLAC must be reversed. Xylazine should not be used for relief of signs of pain in cases of cecal dilatation, because it significantly reduced myo electric activity of the cecum and PLAC for at least 2 hours after treatment. Furthermore, results of this study indicated a trend (P > 0.05) toward increase of cecocolic myoelectric activity after administration of cisapride. It is the authors’ opinion that the potential benefit of cisapride for medical treatment of cecal dilatation in cattle needs further evaluation.
Effect of sodium hexametaphosphate on dental calculus formation in dogs
Authors: Stookey George K. , Warrick Janice M. , Miller Linda L.
Published: January 2024

A series of studies was conducted to identify a practical measure for preventing dental calculus formation in dogs. The studies involved a colony of 27 Beagles that received an initial dental prophylaxis. The dogs were then stratified on the basis of their normal rate of calculus formation and randomly assigned to parallel groups within each strata. During 4-week test periods, a variety of experimental regimens were instituted, followed by clinical assessments of calculus. Major observations were that a crystal growth inhibitor, soluble pyrophosphate, incorporated into a dry dog food modestly reduced calculus formation when used at high concentrations; anticalculus effects attributable to this agent were significant (P < 0.05) only when it was used as a surface coating; the coating of dry dog chow or plain biscuits with a calcium sequestrant, sodium hexametaphosphate (hmp), provided the greatest benefit and resulted in significant (P < 0.05) reductions in calculus formation of about 60 to 80%, depending on the dosage regimen; and the feeding of a single daily snack of 2 hmp-coated plain biscuits (0.6% hmp) decreased calculus formation by nearly 80%. We concluded that the coating of dry dog chow or plain dog biscuits with hmp is an effective means of reducing calculus formation in dogs.
Effects of long-term zearalenone administration on spermatogenesis and serum luteinizing hormone, follicle-stimulating hormone, and prolactin values in male rats
Authors: Milano Guillermo D. , Becú-Villalobos Damasia , Tapia M. Ofelia
Published: January 2024

Body and testis weights, serum luteinizing hormone, follicle-stimulating hormone, and prolactin values and volume fractions of Sertoli cells, spermatogonia, early and late primary spermatocytes, and round and long spermatids were evaluated in 70-day-old male rats treated orally with 20 mg of zearalenone/kg of body weight daily for 5 weeks. A significant (P < 0.05) increase in serum prolactin concentration was consistently observed during the 5 weeks of treatment with zearalenone. Significant changes were not observed in any of the other variables evaluated.
Comparative analyses of peritoneal fluid from calves and adult cattle
Authors: Anderson David E. , Cornwell Dean , Anderson Lane S. , St-Jean Guy , Desrochers André
Published: January 2024

Reference values for hematologic variables change with increasing age in cattle. Therefore, the purpose of the study reported here was to describe the peritoneal fluid constitutents of clinically normal young calves, and to compare cellular concentration and distribution in blood and peritoneal fluid of young calves with those of adult cattle.

Eight healthy 8-week-old male Holstein calves and 8 healthy 3- to 8-year-old Holstein cows were studied. Peritoneal fluid was collected from calves along the ventral midline, 4-cm cranial to the umbilicus. Abdominocentesis was performed in the region of the lower right flank in adult cattle. Correlation analysis, using the Pearson's correlation coefficient, and regression analysis were performed for blood and peritoneal fluid data from calves. Data from calves were compared with those of cows, using Wilcoxon's rank sum test. A P value < 0.05 was considered significant for all tests.

Calves had significantly lower blood eosinophil count (P < 0.003) and plasma protein concentration (P < 0.001) than did cows. Calves had significantly higher peritoneal fluid nucleated cell (P < 0.05) and mononuclear cell (P < 0.05) counts, but lower peritoneal fluid eosinophil cell count (P < 0.003) than did cows. For calves, nucleated cell and lyphocyte cell counts in the blood had a high, positive correlation with those of peritoneal fluid. However, the prediction equation for nucleated cell count accounted for a modest proportion of variability. A prediction equation for peritoneal fluid lymphocyte cell count was established.

On the basis of results of this study, reference ranges established for peritoneal fluid constituents of clinically normal adult cattle may not be appropriate for interpretation of peritoneal fluid analysis of calves.
Effect of long-term administration of a prolonged release formulation of bovine somatotropin (sometribove) on clinical lameness in dairy cows
Authors: Wells S. J. , Trent A. M. , Collier R. J. , Cole W. J.
Published: January 2024

A matched case-control study design was used to assess the effects of long-term administration of a prolonged release formulation of bovine somatotropin (sometribove) on clinical lameness and limb lesions in dairy cows. Cows treated with sometribove for at least 2 lactations (cases) and nontreated dairy cows matched by herd, parity, age, and stage of lactation (controls) in 8 herds were evaluated for clinical lameness (as assessed by gait abnormality) and limb lesions by 2 observers, using a standardized scoring procedure at a single herd visit. Although a high proportion of the study cows were clinically lame (43%), an association was not detected between chronic administration of sometribove and prevalent lameness. Of 21 types of limb lesions identified, 2 were positively associated and 2 were negatively associated with long-term sometribove use. Superficial laceration of the tarsus (odds ratio [or] = 2.1) and superficial swelling of the metatarsophalangeal joint (or = 4.5) were positively associated with sometribove treatment, whereas femoral lesions (or = 0.2) and superficial lacerations of the femur (or = 0.14) were negatively associated with sometribove treatment.
Effectiveness of the ivermectin sustained-release bolus in the control of bovine nematodosis
Authors: Yazwinski T. A. , Featherston H. , Tucker C.
Published: January 2024

Objective

To evaluate the nematocidal effectiveness of the ivermectin sustained-release bolus throughout its 135-day delivery period.

Design

Twenty-four naturally infected calves were randomly allocated to 1 of 3 equivalent experimental groups: group-T1 calves were untreated controls, group-T2 calves each received a sustained-release bolus on trial day 0, and group-T3 calves were rendered nematode-free and used at 35-day intervals during the study as tracers. One contaminated pasture was used for all principal calves for the 135-day grazing interval of the study. Calves of groups T1 and T2 were also artificially administered mixed infective nematode larvae at intervals during the grazing period, after which, all calves were confined to concrete for 21 days prior to necropsy.

Animals

All calves were approximately 6 months old on trial day 0, weighed from 136 to 216 kg, and were of mixed breeding and sex.

Procedure

At intervals during the study, feces from all calves were analyzed for nematode egg counts, and all calves were weighed and examined for bolus retention (T2 calves only). For nematode recovery, all calves were necropsied 21 to 22 days after removal from the contaminated pasture.

Results

Parasitic populations of Haemonchus, Ostertagia, Trichostrongylus, Cooperia, Bunostomum, and Oesophagostomum spp were significantly reduced in cattle treated with the ivermectin sustained-release bolus.

Conclusion

The nematocidal activity of the ivermectin sustained-release bolus proved highly effective, with > 98% efficacy for all nematode species present.
Influence of four diets on uric acid metabolism and endogenous acid production in healthy Beagles
Authors: Bartges Joseph W. , Osborne Carl A. , Felice Lawrence J. , Unger Lisa K. , Koehler Lori A. , Bird Kathy A. , Chen Menglan
Published: January 2024

Objective

To evaluate the influence of 3 diets used to dissolve or prevent ammonium urate uroliths in dogs, and a diet formulated for growth, on 24-hour excretions of uric acid, ammonia, net acid, titratable acid, bicarbonate, and creatinine: 24-hour urine volumes: pH values of 24-hour urine samples; plasma uric acid concentration; serum creatinine concentration; and endogenous creatinine clearance values.

Design

Randomized block.

Animals

Six reproductively intact female Beagles, 3.9 to 4.2 years old, weighing 8.5 to 11.1 kg.

Procedures

Four diets were evaluated for their ability to dissolve magnesium ammonium phosphate hexahydrate (struvite) uroliths (diet S); to minimize uric acid excretion (diet U); to minimize clinical signs associated with renal failure (diet K); and to promote growth in pups (diet P). Each diet was fed for 14 days; then 24-hour urine samples were collected. An adult maintenance diet was fed during a 7-day washout period.

Results

Consumption of diet U was associated with lowest plasma uric acid concentration, lowest 24-hour urinary uric acid, ammonia, titratable acid, and net acid excretions, lowest endogenous creatinine clearance values, highest 24-hour urinary bicarbonate excretion and urine pH values, and highest 24-hour urine volumes. Consumption of diet P was associated with opposite results; results of consumption of diets S and K were intermediate between those for diets U and P.

Conclusion

Consumption of diet U by healthy Beagles is associated with reduced magnitude of urinary excretion of uric acid and ammonia, with alkaluria, and with polyuria, which may be beneficial in the management of ammonium urate uroliths in dogs.

Clinical Relevance

Results support use of diet U for management of ammonium urate urolithiasis in dogs.(Am J Vet Res 1996;57:324-328)
Myocarditis in mice and guinea pigs experimentally infected with a canine-origin Borrelia isolate from Florida
Authors: Breitschwerdt Edward B. , Geoly Frank J. , Meuten Donald J. , Levine Jay F. , Howard Peter , Hegarty Barbara C. , Stafford Laurie C.
Published: January 2024

Objective

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

Design

Prospective experimental infection.

Animals

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

Procedure

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

Results

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

Conclusions

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

Objective

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

Design

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

Animals

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

Procedure

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

Results

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

Conclusions

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

Objective

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

Design

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

Animals

32 adult mixed-breed dogs of either sex.

Procedure

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

Results

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

Conclusion

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

Clinical Relevance

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

Objective

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

Design

Event-time analysis (survival analysis).

Sample Population

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

Procedure

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

Results

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

Conclusions

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

Objective

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

Design

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

Procedure

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

Results

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

Conclusions

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

Clinical Relevance

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

Objective

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

Animals

5 healthy unsedated Friesian calves.

Procedure

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

Results

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

Conclusions

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

Clinical Relevance

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

Objective

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

Design

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

Animals

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

Procedure

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

Results

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

Conclusion

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

Objective

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

Animals

20 colostrum-deprived, cesarean-derived pigs.

Design and Procedure

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

Results

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

Conclusions

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

Clinical Relevance

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

Objective

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

Design

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

Animals

40 ocular-normal dogs.

Procedure

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

Results

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

Conclusions

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

Objective

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

Design

Case-control study.

Animals

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

Procedure

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

Results

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

Clinical Relevance

Avoiding the use of toe grabs should decrease the incidence of FMI, especially SAF, in Thoroughbred racehorses. The use of rim shoes that are more consistent with natural hoof shape may decrease injury risk. (Am J Vet Res 1996;57:1147-1152)