bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of Pasteurella haemolytica leukotoxic activity by bovine serum albumin
Authors: Waurzyniak Barbara J. , Clinkenbeard Kenneth D. , Anthony W.Confer Anthony W. Confer , Srikumaran S.
Published: January 2024

Growth of Pasteurella haemolytica A1 in RPMI 1640 medium containing 0.5% bovine serum albumin (bsa) for 2.5 hours enhanced culture supernatant leukotoxic activity (30,700 ± 12,900 toxic units/ml, compared with leukotoxic activity of culture supernatants produced in RPMI 1640 medium alone (120 ± 40 toxic units/ml). Gel filtration chromatography of the leukotoxic activity from RPMI 1640 medium supernatants in buffer containing 50 mM NaCl indicated a single leukotoxic activity peak (peak I) eluting near the gel resin molecular mass exclusion limit (estimated molecular mass of approx 8,000 kd). In contrast, culture supernatants produced in RPMI 1640 plus bovine serum albumin medium (RPMI + bsa) had peak I and 2 additional leukotoxic activity peaks (peaks II and III) with estimated molecular mass of approximately 80 and < 30 kd, respectively. All leukotoxic activity peaks were composed of approximately 100-kd molecular mass leukotoxin protomer, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with a monoclonal antibody against leukotoxin. Subjecting culture supernatant leukotoxic activity produced in RPMI + bsa to gel filtration chromatography in buffer containing 500 mM NaCl or 6M urea resulted in detection of only a single leukotoxic activity peak with estimated approximate molecular mass of 250 and 800 kd, respectively. These findings suggest that Phaemolytica exists as a high molecular mass aggregate with low leukotoxic activity which, in the presence of bsa, partially disaggregates to multiple toxin forms with enhanced leukotoxic activity. Some of these leukotoxin forms interact with dextran-based gel resins at low ionic strength.
Differential artificial ventilation in anesthetized horses positioned in lateral recumbency
Authors: Moens Y. , Lagerweij E. , Gootjes P. , Poortman J.
Published: January 2024

Effects of differential ventilation on gas exchange were studied in 7 isoflurane-anesthetized, laterally recumbent horses, and were compared with effects of conventional ventilation, using similar minute volume. A tracheal tube-in-tube intubation technique allowed each lung to be connected separately to an anesthetic circle system with a ventilator. Two distribution patterns of tidal volume were investigated; half the tidal volume was distributed to each lung and two-thirds the tidal volume was distributed to the dependent lung. Effects of the combination of these patterns with positive end-expiratory pressure (peep) of 10 and 20 cm of H2O to the dependent lung were investigated.

Differential ventilation maintained PaCO2, but significantly increased PaCO2 from 180 to 270 mm of Hg (+44%) and decreased shunt perfusion from 22 to 19% (-15%), regardless of the distribution pattern used. Mean airway pressure was lower than the value detected during conventional ventilation. The combination of differential ventilation with selective peep was followed by a decrease in PaCO2 and further increase of PaCO2 and decrease of shunt, which were similar for both distribution patterns. Effects of peep of 20 cm of H2O were more pronounced than those of peep of 10 cm of H2O. Owing to the combined effects of differential ventilation and selective peep, PaCO2 increased to 399 mm of Hg and shunt decreased to 15%. This represents increase of 112% and decrease of 33% respectively, compared with values for conventional ventilation. Mean airway pressure increased maximally to 23 cm of H2O, which was 11 cm of H2O greater than the value for conventional ventilation. During differential ventilation, alveolar dead space in the dependent lung became greater than that in the nondependent lung and maximum was 39%. There were no significant changes in arterial blood pressure. Beneficial effects on gas exchange can be explained by improved matching of ventilation and perfusion, possibly attributable to reopening of previously closed units in the dependent lung.
Effect of prior lavage on bronchoalveolar lavage fluid cell population of lavaged and unlavaged lung segments in horses
Authors: Sweeney Corinne R. , Rossier Yves , Ziemer Ellen L. , Lindborg Susan R.
Published: January 2024

Bronchoalveolar lavage (bal) was performed on 16 horses to determine whether it caused local or diffuse inflammation in the lungs. In 7 horses, bal was performed in both lungs twice, 48 hours apart. Although total cell counts of the bal samples did not change significantly, there were increased numbers and percentage of neutrophils in the second lavage fluid samples. In 5 horses, bal was performed in 1 lung and repeated 48 hours later in the same lung and in the corresponding airway in the contralateral lung. The absolute cell count and percentage of neutrophils were significantly (P = < 0.05) increased in the second sample from the lung that was lavaged twice. In 4 horses, bal was performed in 1 lung and 48 hours later, repeated in an adjacent airway to the first bal site, and in the corresponding airway in the contralateral lung. Significant differences were not detected the total or differential cell counts of the bal fluid recovered at any time, except for an increase in neutrophil percentage in the second sample in the contralateral lung. The increased neutrophil percentage values were within the range of normal for healthy horses.

Results of the study suggested that, in horses, bal induces a localized pulmonary neutrophil influx that persists at least 48 hours and is characterized by a relative and absolute increase in the number of neutrophils in the lavage fluids.
Experimentally induced infection with bluetongue virus serotype 11 in cows
Authors: Parsonson Ian M. , Thompson Lee H. , Walton Thomas E.
Published: January 2024

The consequences of inoculation of bluetongue virus (btv) serotype 11 into 16 susceptible cows either at the time of breeding or at specified stages of pregnancy were studied. The cows were free of btv or epizootic hemorrhagic disease virus, and none had antibodies to btv before virus inoculation. A group of 4 cows was mated naturally to a bull reported to shed btv-11 (CO75B300 strain) in the semen. The bull was suspected of infecting cows at mating with btv-11, which subsequently transplacentally infected the developing fetuses and induced persistently infected and congenitally malformed progeny.

Two groups of 4 pregnant cows were inoculated with an insect-derived strain of btv-11 (CO75B300), one group by direct deposit into the uterus at estrus, the other, by intradermal and sc administrations. A 90-day fetus was inoculated in utero with virus from the same pool.

Four pregnant cows were inoculated with sheep blood-passaged virus of the same btv-11 strain (CO75B300) by intradermal and sc routes. Three cows were inoculated with btv-free suspending fluids and ovine erythrocytes by the intrauterine and intradermal-sc routes and were used as in-contact controls.

Infection with insect-derived btv-11 was confirmed in 3 cows of 1 group by virus isolation and by detection of serum antibodies. The 4 cows inoculated with sheep blood suspension of btv- 11 developed viremia and produced antibodies to the virus. None of the cattle had clinical signs of bluetongue, other than 2 cows that had a slight rectal temperature increase on postinoculation day 4.

All cows and fetuses that ranged in gestational age from 69 to 217 days appeared grossly normal at necropsy. Antibodies were not detected in fetal blood. Viral antigen was not detected in fetal tissues by inoculation into sheep or by immunofluoerscence, and viral rna was not detected by use of the polymerase chain reaction.

Developmental deformities were not seen in any fetus. The btv-11 was not transmitted via the bull semen after natural mating. The btv-11 strain CO75B300, isolated from this bull and passaged either as insect-derived or ovine erythrocyte suspensions, infected 8 cows. However, the virus was not transplacentally transmitted to their fetuses. It was concluded that there was no evidence for congenital btv-11 infection in this study.
Blood coagulopathy in dogs with shock induced by injection of heartworm extract
Authors: Kitoh K. , Watoh K. , Kitagawa H. , Sasaki Y.
Published: January 2024

A crude, whole-body extract of female heartworms was administered iv to 10 dogs with and 13 dogs without heartworm (hw) infection. Shock developed in 8 of 10 infected dogs and 11 of 13 noninfected dogs, and blood coagulopathy was observed in 12 of 19 dogs with shock. Prevalence and severity of blood coagulopathy were proportionate to prevalence and severity of shock. Platelet count decreased in all dogs with shock with or without blood coagulopathy; thus, the decrease in platelet count might be related to shock. In 4 dogs, activated partial thromboplastin time (aptt) was prolonged - 192.0 seconds at 30 minutes after hw injection - and prothrombin time (pt) was increased-13.8 seconds at initial collapse. In 8 dogs, aptt was increased - 200 seconds for 2 hours after hw injection - and pt was increased - 200 seconds at 30 minutes after the injection. The aptt prolongation might have been caused mainly by decreases in activities of factors VIII, IX, XI, and XII of the intrinsic blood coagulation pathway. In dogs with severely prolonged pt plasma fibrinogen concentration and factor II activity decreased slightly. Prolonged pt was corrected in vitro by addition of normal plasma at high concentration (> 80 %), but prolonged aptt could not be corrected in vitro by addition of 80 % normal plasma. Serum fibrin degradation products concentration was < 10 μg/ml, and soluble fibrin monomer complex was negative in all dogs. Thrombi were not found in blood vessels of any organ at necropsy and after histologic study. Therefore, it was suggested that blood coagulopathy resulting from inhibition of coagulation factor activities might develop in shock induced by hw extract.
Whole-blood platelet aggregation, buccal mucosa bleeding time, and serum cephalothin concentration in dogs receiving a presurgical antibiotic protocol
Authors: Schermerhorn Thomas , Barr Stephen C. , Stoffregen Dana A. , Koren-Roth Yossi , Erb Hollis N.
Published: January 2024

Whole-blood platelet aggregation (using the impedance method) and adenosine triphosphate (atp) release, buccal mucosal bleeding time (bt), and serum cephalothin concentration were measured in 21 adult female Beagles before (pre) and 1 hour (1hr) after iv administration of cephalothin (22 mg/kg). A second injection of cephalothin (22 mg/kg) was given 3 hours after the first, and blood samples were obtained 1 hour (4 hr, 4 hours after the first injection) and 3 hours (6 hr, 6 hours after the first injection) after the second injection. Samples of jugular blood were obtained from each dog, using citrate as an anticoagulant. A platelet count was obtained for each sample. Platelet aggregation and atp released from the aggregating platelets were measured within 1 hour of sample collection, using a whole-blood aggregometer. Adenosine diphosphate (ADP) and collagen were used as aggregating agents. Aggregation was measured over 6 minutes for each aggregating agent; atp release in response to collagen, but not to ADP, was measured over the same period. For 1 hr samples, there was a significant (P < 0.01) reduction from pre values in the ability of platelets to aggregate in response to ADP. Bleeding time was determined, using a published procedure, with each dog as its own control. Bleeding time during the same period was found to be significantly increased over pre values for 1 hr (P < 0.01) and 6 hr (P < 0.02) samples. There was no significant difference between bt for 1 hr and 4 hr samples. Median serum cephalothin concentrations in pre, 1 hr,4hr, and 6 hr samples did not correlate significantly to platelet aggregation, atp release, platelet count, or bt at any time during the study. Because serum cephalothin concentration was so low, and because there are few reports of the kinetics of cephalothin after iv administration, serum cephalothin was measured in 2 dogs over 2 hours after single iv administration of cephalothin. Values reached a peak at 2 minutes after drug administration, then decreased rapidly over 10 to 15 minutes, and were low by 2 hours.
Investigation of oxygen-derived free radical generation in cancellous bone specimens obtained from dogs
Authors: Lewis Daniel D. , Church Daniel F. , Hosgood Giselle , van Ee Rene T.
Published: January 2024

Generation of free radicals and the ability ofvarious antioxidants to attenuate radical production in freshly procured cancellous bone specimens was investigated, using spin-trapping and electron spin resonance (esr) techniques. Seven core cancellous bone specimens, 10 mm long and 7.9 mm in diameter, were obtained using aseptic technique, from the proximal portion of the humerus of 9 adult mixedbreed dogs. One core cancellous bone specimen from each dog was incubated in spin trap α-phenyl-N tert-butylnitrone in Eagle's minimum essential medium and served as a control. The other 6 specimens from each dog were incubated in α-phenyl-N-tertbutylnitrone/Eagle's minimum essential medium plus 1 of the following antioxidants: superoxide dismutase, catalase, superoxide dismutase/catalase, indomethacin, allopurinol, or deferoxamine mesylate. All specimens were incubated at 26 C for 90 minutes, then frozen at -20 C until they were prepared for analysis by esr spectroscopy. Each specimen was thawed, homogenized, and extracted in a low-dielectric organic solvent prior to obtaining an esr spectrum which was analyzed for hyperfine splitting constants to identify radicals. Each first-derivative spectrum was digitally double-integrated to obtain an area: these areas were used to compare intensities of the spin. For each treatment group, the areas from the treated specimens were compared with the areas from the control specimens, using a paired t-test. Significance was accepted at P ≤ 0.05.

Spin adducts were detected in all cancellous bone specimens. Specimens incubated in deferoxamine (P = 0.0017) and superoxide dismutase/catalase (P = 0.0452) had significantly smaller areas than did control specimens. The areas for the other treatment groups did not differ significantly from controls. Our results substantiate free radical production in freshly procured cancellous bone specimens and that radical formation is attenuated by in vitro incubation with deferoxamine or superoxide dismutase/catalase.
Effect of intravenous administration of hydroxyethyl-starch-deferoxamine on oxygen-derived free radical generation in cancellous bone specimens obtained from dogs
Authors: Lewis Daniel D. , Church Daniel F. , Hosgood Giselle
Published: January 2024

The ability of iv administered hydroxyethyl-starch-deferoxamine to attenuate radical production in freshly procured cancellous bone specimens was investigated, using spin-trapping and electron spin resonance (esr) techniques. A core cancellous bone specimen 10 mm long and 5.6 mm in diameter was obtained, using aseptic technique, from the proximal portion of the humerus of 30 adult mixed-breed dogs. After procurement of the initial bone specimen, 10 dogs received a 10 % solution of hydroxyethyl-starch-deferoxamine in 0.9% NaCl (50 mg/kg of body weight, iv), 10 dogs received an equivalent volume (5 ml/kg, iv) of a 10% solution of hydroxyethyl-starch in 0.9 % NaCl, and 10 dogs received 0.9 % saline solution (5 ml/kg, iv). A second core cancellous bone specimen was obtained from the contralateral humerus of each dog 45 minutes after treatment. All specimens were individually incubated in the spin trap α-phenyl-N-tert-butylnitrone in Eagle's minimum essential medium, at 26 C for 45 minutes, then were frozen at -20 C until they were prepared for analysis by esr spectroscopy. Each specimen was thawed, homogenized, and extracted in a low-dielectric organic solvent prior to obtaining an esr spectrum, which was analyzed for hyperfine splitting constants for radical identification. Each first-derivative spectrum was digitally double-integrated to obtain an area; these areas were used to compare intensities of the spin adducts. Difference in the area obtained before and after treatment for each dog was expressed as a ratio of that dog's pretreatment area ([pretreatment-posttreatment ]/pretreatment). The calculated ratios for saline-, hydroxyethyl-starch-, and hydroxyethyl-starch-deferoxamine-treated dogs were compared, using a Kruskal-Wallis (KW) nonparametric test for multiple comparisons of ranked data. Significance was determined at P ≤ 0.05. Ad hoc comparisons were performed, using the KW procedure for individual comparisons, with a set at 0.05.

The mean ± sd and median ratio for each of the treatment groups were: saline-treated dogs, 0.005 ± 0.40 and 0.045; hydroxyethyl-starch-treated dogs, -0.063 0.27 and -0.025; hydroxyethyl-starch-deferoxamine-treated dogs, 0.261 ± 0.278 and 0.335, respectively. There was a significant (P < 0.01, KW) difference in the ratios between treatment groups. Ratios for hydroxyethyl-starch-deferoxamine-treated dogs were significantly (P < 0.05, KW) higher than that for hydroxyethyl-starch-treated dogs but not for saline-treated dogs. The ratios for saline- and hydroxyethyl-starch-treated dogs were not significantly different. We could not associate significant attenuation of radical generation in freshly harvested core cancellous bone specimens with iv administration of hydroxyethyl-starch-deferoxamine. The potential for unconjugated hydroxyethyl-starch to function as an oxidant must considered.
Pathologic findings of experimentally induced Streptococcus uberis infection in the mammary gland of cows
Authors: Thomas Lewis H. , Haider Wolfram , Hill Alan W. , Cook Roy S.
Published: January 2024

Twenty-five quarters of 12 daily cows, 3 to 8 years old, with a bacteriologic history of freedom from infection with Streptococcus uberis were inoculated via the teat canal with S uberis (23 quarters) or sterile medium (2 quarters). The cows were sent to slaughter 1, 3, or 6 days later. Acute inflammatory response involving accumulation of large numbers of polymorphonuclear, neutrophilic leukocytes (neutrophils) in the secretory acini was recognized after 24 hours in infected cows. After 6 days, the neutrophil response was still evident, but infiltration of septa by lymphocytes, septal edema, extensive vacuolation of secretory cells, focal necrosis of alveoli, small outgrowths of the secretory and ductular epithelium, and widespread hypertrophy of the ductular epithelium also were recognized. Early stages of involution and fibrosis also were evident at that stage. Streptococci were identified by immunoperoxidase labeling, free or phagocytosed, in macrophages; in the alveolar lumina, adherent to damaged secretory or ductular epithelium; in the subepithelium and septal tissue; and in lymphatic vessels and lymph nodes. The importance of the macrophage as the primary phagocytic cell is highlighted, and doubt is cast on the value of the exuberant neutrophil response by the host in defense of the gland.
Changes in renal function associated with treatment of hyperthyroidism in cats
Authors: Graves Thomas K. , Olivier N. Bari , Nachreiner Ray F. , Kruger John M. , Walshaw Richard , Stickle Russ L.
Published: January 2024

We measured glomerular filtration rate (gfr) estimated by plasma disappearance of 99mTc-labeled diethylenetriaminepentaacetic acid, serum concentrations of thyroxine (T4), creatinine, and urea nitrogen, and urine specific gravity in 13 cats with naturally acquired hyperthyroidism before and 30 days after treatment by bilateral thyroidectomy, and in a group of 11 control cats. Mean (±sd) serum T4 concentration decreased from a pretreatment value of 120.46 (± 39.21) nmol/L to a posttreatment value of 12.15 (± 6.26) nmol/L (P < 0.0001; reference range, 10 to 48 nmol/L). Treatment of hyperthyroidism resulted in a decrease in mean (± sd) glomerular filtration rate, from 2.51 (± 0.69) ml/kg of body weight/min to a posttreatment value of 1.40 (± 0.41) ml/kg/min (P < 0.0001). Mean serum creatinine concentration increased from 1.26 (± 0.34) mg/dl to 2.05 (± 0.60) mg/dl (P < 0.01). Mean serum urea nitrogen concentration increased from 26.62 (± 6.83) mg/dl to a mean postthyroidectomy concentration of 34.92 (± 8.95) mg/dl (P < 0.01). All changes were significant. Two cats developed overt renal azotemia after treatment of hyperthyroidism. Our results provide further evidence that treatment of hyperthyroidism can result in impaired renal function. In addition, our results suggest that, in some instances, thyrotoxicosis might mask underlying chronic renal insufficiency.
Effects of chloramphenicol on infusion pharmacokinetics of propofol in Greyhounds
Authors: Mandsager Ronald E. , Clarke Cyril R. , Shawley Richard V. , Hague Christinia M.
Published: January 2024

To investigate the effect of chloramphenicol, a cytochrome P-450 inhibitor, on the pharmacokinetics of propofol, either chloramphenicol (50 mg/kg of body weight, iv) or saline solution was administered iv to 5 Greyhounds in randomized manner, with at least 2 weeks between trials. Thirty minutes after either chloramphenicol or saline treatment, a bolus dose of propofol (10 mg/kg, iv) was administered, followed by a 2-hour infusion of propofol (0.4 mg/kg/min, iv). Samples for determination of blood propofol concentration were collected sequentially over a 6-hour period during each trial. After termination of propofol infusion, the time to spontaneous head lift, extubation, sternal recumbency, and standing was recorded. Blood propofol concentration was determined by use of high-performance liquid chromatography. Concentration-time data were fitted to a two-compartment open pharmacokinetic model and pharmacokinetic variables were determined, using a microcomputer program for modeling and simulation of concentration-time data. The effect of chloramphenicol on the pharmacokinetics of propofol and recovery time were evaluated, using paired t-tests and Wilcoxon's test for parameters that are not normally distributed (t½(β), Vd(ss), ClB). Significant (P < 0.05) effects of chloramphenicol pretreatment included increased t1/2(β) (by 209%), and decreased ClB (by 45%), and prolonged recovery indices (by 768 to 946%). These results indicate that cytochrome P-450 metabolic pathways have an important role in propofol clearance and propofol anesthetic recovery in Greyhounds.
Serum swainsonine concentration and α-mannosidase activity in cattle and sheep ingesting Oxytropis sericea and Astragalus lentiginosus (locoweeds)
Authors: Stegelmeier Bryan L. , James Lynn F. , Panter Kip E. , Molyneux Russell J.
Published: January 2024

Serum α-mannosidase activity and swainsonine concentration were determined in 4 cattle and 15 sheep (3 groups of 5 each) that were administered ground locoweed (Oxytropis sericea or Astragalus lentiginosus) containing swainsonine at dosages of approximately 0.8 mg/kg of body weight/d (cows, 30 days each) and 0, 1.0, and 1.5 mg/kg/d (sheep, 11 days each). The cattle developed mild clinical signs of locoism, including signs of depression, lethargy, and slight intention tremors. Clinical signs of toxicosis were not observed in the sheep. Within 24 hours of initial treatment, serum α-mannosidase activity in cows and sheep, measured by the release of 4-methylumbelliferone from an artificial substrate, was markedly decreased to 28 and 40 μmol of 4-methylumbelliferone/L, respectively. Mean serum α-mannosidase activity of control cows and sheep was 400 ± 94 and 422 ± 42 (mean ± sd), respectively. In the treated animals, decreased serum α-mannosidase activities returned to normal or higher activities within 6 days after treatment was discontinued. Using a jack bean α-mannosidase assay, increased swainsonine activity (153, 209, and 381 ng/ml, respectively) was detected in the serum of cattle and of sheep in the high- and low-dose groups within 24 hours after treatment with locoweed. Swainsonine concentration remained high, with mean concentrations of 204, 432, and 395 ng/ml (cows and 2 sheep groups, respectively) during the treatment period. After treatment, swainsonine was rapidly cleared, with estimated serum half-life of 16.4, 17.6, and 20.3 hours (cows, and high- and low-dose sheep groups, respectively). Significant differences in either α-mannosidase activity or swainsonine concentration were not detected between the 2 groups of treated sheep. These results suggest that serum α-mannosidase and swainsonine values are sensitive indicators of locoweed intoxication in cattle and sheep. Furthermore, it suggests that swainsonine is rapidly absorbed, resulting in rapid inhibition of serum α-mannosidase activity, leading to high serum swainsonine concentration. After exposure is eliminated, swainsonine is rapidly cleared from the serum, with serum α-mannosidase activity returning to normal values shortly thereafter.
Fluid, electrolyte, and packed cell volume shifts in racing Greyhounds
Authors: Toll P. W. , Gaehtgens P. , Neuhaus D. , Pieschl R. L. , Fedde M. R.
Published: January 2024

Arterial blood samples were obtained at rest, just before, and 5 minutes after a 704-m race, to quantify changes in hematologic variables, plasma electrolyte and protein concentrations, osmolality, and acid/base variables. Changes in plasma volume were estimated from the change in plasma protein concentration. Immediately prior to the race, plasma volume decreased by 10% from rest and total circulating rbc volume increased by 60%, attributable to increased rbc number rather than size. Increases in blood volume (VB) by 24% and pcv by 29% also were detected before the race. Five minutes after the race, plasma volume was 21% below the resting value and total circulating rbc volume had increased 73% above the resting value, resulting in a 40% increase in pcv. Contraction of the spleen appeared responsible for increased pcv and VB before the race and maintenance of VB after the race.

Plasma chloride concentration was the same before and after the race; the chloride content of the plasma decreased by the same fraction (22%) as did the plasma volume, indicating Cl- loss from the plasma. Plasma Na+ content decreased by a smaller fraction (13%), causing Na+ concentration to increase from 151 mEq/L at rest to 167 mEq/L after the race. Assuming that Na+ concentration was the same throughout the extracellular fluid, H2O likely moved into the intracellular compartment. As a consequence of these changes, the inorganic strong ion difference in plasma increased by about 16 mEq/L, tending to minimize the acid/base disturbance induced by the 33 mEq/L increase in lactate concentration.

Results indicated that the physiologic changes taking effect during strenuous sprint exercise in Greyhounds enhance blood volume and aid in acid/base homeostasis, both of which are adaptive for this type of exercise.
Prophylactic effect of dietary zinc in a laboratory mouse model of swine dysentery
Authors: Zhang Peng , Duhamel Gerald E. , Mysore Jagannatha V. , Carlson Michael P. , Schneider Norman R.
Published: January 2024

Reduced prevalence of diarrhea and mortality has been reported after dietary supplementation with zinc compounds in swine with naturally acquired colibacillosis and those challenge-exposed with Serpulina hyodysenteriae; however, the usefulness of this approach for control of enteric diseases of swine remains to be determined. To examine the effect of dietary zinc-containing compounds on the colonization and development of cecal lesions associated with S hyodysenteriae infection, a defined diet alone or with added ZnO, ZnSO4, or Zn-methionine complex to a final concentration of approximately 6,000 mg of Zn2+/kg of complete feed was fed ad libitum to 156 female mice (strain C3H/HeN) for 10 days prior to oral inoculation either with S hyodysenteriae or sterile trypticase soy broth. Rations were continued for 42 days, while at weekly intervals, 3 mice/group were necropsied for determination of body weight, cecal weight, liver zinc concentration, presence of S hyodysenteriae in the cecum, and gross and histologic assessments of cecal lesions. From postinoculation day 0 to 42, the liver zinc concentration of mice fed the zinc-supplemented diets was approximately twice that of mice fed the basal diet, irrespective of the source of zinc. From postinoculation day 7 through 42, the overall recovery rate of S hyodysenteriae in infected mice fed the basal diet was 77.8%. In contrast, recovery rates of S hyodysenteriae from S hyodysenteriae-inoculated mice fed the zinc-supplemented diets were 0% for Zn-methionine and ZnO and 16.7% for ZnSO4. Mice fed the basal diet had significantly (P < 0.05) higher weight gain than mice fed the zinc-supplemented diets. However, the severity of cecal lesions, as determined by histologic examination and quantitative determination of longitudinal crypt length of the cecum was significantly (P < 0.05) less in mice fed the zinc-supplemented diets than in mice fed the basal diet. Data from this study indicate that dietary supplementation with 6,000 mg of zinc/kg of feed significantly reduced the recovery rate of S hyodysenteriae and provided partial protection against development of cecal lesions in mice inoculated with S hyodysenteriae. However, at this concentration, zinc had a deleterious effect on growth of the mice.
Effect of methacholine on mucociliary transport in bovine trachea in vitro
Authors: Mars Maria H. , Henricks Paul A. J. , Hajer Rob , Breukink Henk J.
Published: January 2024

A method is described to evaluate pharmacologic influence on bovine tracheal mucus transport in vitro. In this model, cholinergic agonist methacholine stimulated transport velocity. Methacholine at concentration of 10−6M increased velocity by 13.6%, whereas 10−5M increased velocity by 26%. Stimulation was inhibited by atropine.
Electrophysiologic evaluation of the phrenic nerve-diaphragm pathway in an intact, conscious calf model
Authors: Desmecht Daniel J.-M. , Linden Annick S. , Lekeux Pierre M.
Published: January 2024

Owing to technical and ethical limitations, a substantial part of the knowledge about the pathophysiologic mechanism of the human diaphragm has been obtained from studies in which phrenic nerve activation was usually carried out by direct surgical exposure of the nerves in the neck of deeply anesthetized, mechanically ventilated animals. Novel information has been gleaned from such studies, but the restrictive conditions under which it was collected preclude reliable extrapolation. We, therefore, addressed the question of whether accurate electrophysiologic evaluation of the phrenic nerve-diaphragm pathway can be performed in intact, nonanesthetized calves.

Transjugular phrenic activation was well tolerated, safe, specific, and able to achieve constant symmetric and supramaximal phrenic stimulations during prolonged periods. Eighteen noninvasive cutaneous and esophageal reception circuits were tested for their ability to record the diaphragmatic evoked potential. In addition, they were compared for specificity and reproducibility of the recorded potentials during prolonged periods of tidal or stimulated respiration. The best diaphragmatic potential was recorded from surface electrodes attached to the skin of the ninth and tenth intercostal spaces, using a xyphoidian reference.

We describe a method that allows easy, longterm, and reliable electrophysiologic evaluation of the phrenic nerve-diaphragm pathway in intact, conscious calves. It is hoped that such a model will produce relevant novel information regarding pathophysiology of the diaphragm.
Assessment of the effectiveness of vaccination against pseudorabies in finishing pigs
Authors: Stegeman Arjan , Van Nes Arie , de Jong Mart C. M. , Bolder Freddie W. M. M.
Published: January 2024

Whereas the clinical efficacy of vaccination against pseudorabies has been studied extensively, methods to evaluate the influence of vaccination on pseudorabies virus (prv) transmission have only recently become available. In this study, prv transmission and growth performance in finishing pigs vaccinated either once or twice were compared.

The incidence of prv infections was significantly (P = 0.039) higher in the group vaccinated once (38%) than in the group vaccinated twice (10%). The reproduction ratio R, which is defined as the average number of new infections caused by 1 infectious individual, was estimated in both groups. This ratio was also significantly (P = 0.025) higher among single vaccinated pigs (R = 3.4) than among pigs that had received double vaccination (R = 1.5). In compartments where serologic evidence of prv introduction was observed, the mean daily weight gain was significantly (P = 0.029) lower in pigs vaccinated once (698 g/d) than in pigs vaccinated twice (721 g/d).

Results of this study document the possibility to objectively evaluate the effect of vaccination on prv transmission under field conditions. From the results, we concluded that double vaccination is advantageous in populations of finishing pigs at risk for prv introduction. However, even among pigs vaccinated twice, extensive spread of prv can occur.
Response to demineralized bone matrix implantation in foals and adult horses
Authors: Douglas Janet , Clarke Andrew
Published: January 2024

Equine demineralized bone matrix, particle size 2 to 4 mm, was implanted sc and IM in 4 foals and 4 adult horses. The implants were removed between 5 and 8 weeks after implantation. Bone formation was induced by sc and IM implantations in all animals. The implantation site had a marked effect on the amount of bone that developed, bone being formed earlier and in greater amounts when the matrix was implanted IM. The amount of bone formed increased with increasing time after matrix implantation at both sites. Demineralized bone matrix implantation also led to formation of small amounts of chondroid tissue; this tissue was more common in IM than sc matrix implants, and increased in amount with increasing time after implantation. Formation of this chondroid tissue did not precede the formation of bone, and there was no evidence that implantation of demineralized bone matrix in horses induced endochondral ossification. Age of the host did not appear to affect the response.
Abortion in heifers inoculated with a thymidine kinase-negative recombinant of bovine herpesvirus 1
Authors: Miller Janice M. , Whetstone Cecelia A. , Bello Leonard J. , Lawrence William C. , Whitbeck J. Charles
Published: January 2024

The Cooper isolate of bovine herpesvirus 1 (bhv-1) was used to produce a thymidine kinase-negative ( tk−) recombinant by insertion of a β-galactosidase (bgal) expression cassette into the tk coding region. The recombinant virus (tk− bgal+) was tested for abortifacient activity in cattle by inoculation of 5 pregnant heifers at 25 to 29 weeks gestation. Five additional heifers were inoculated with the Cooper tk−positive ( tk+) virus to serve as controls. After inoculation, both groups of heifers developed similar febrile responses and neutralizing antibody titers. Virus was isolated from blood of all heifers during the first postinoculation (pi) week, and isolation frequencies were similar for both groups. In contrast, whereas virus was isolated from many of the nasal and vaginal swab specimens of heifers inoculated with tk+ virus, only rare virus isolations were made from the heifers given tk− bgal+ virus. All heifers inoculated with tk+ virus aborted between pidays 19 and 35. The finding of characteristic microscopic lesions and viral antigen in fetal tissues indicated that the abortions were caused by bhv-1 infection. Virus was isolated from 3 fetuses, and all isolates were tk+. Two heifers inoculated with tk− bgal+ virus aborted at PI days 25 and 39. Fetal tissues had typical bhv-1 microscopic lesions and viral antigen. Virus was isolated from blood of both fetuses, and the isolates were tk− bgal+. Results of this study indicate that inactivation of the tk gene reduces, but does not eliminate, the abortifacient activity of bhv-1.
Influence of two amounts of dietary casein on uric acid, sodium urate, and ammonium urate urinary activity product ratios of healthy Beagles
Authors: Bartges Joseph W. , Osborne Carl A. , Felice Lawrence J. , Brown Charles , Allen Timothy A. , Koehler Lori , Unger Lisa , Bird Kathy , Chen Menglan
Published: January 2024

Casein has been used as a protein source in diets designed to dissolve canine ammonium urate uroliths and to prevent their recurrence, because it contains fewer purine precursors than do many other sources of protein. However, an important question is whether reduced quantities of dietary casein have any benefit in modifying saturation of urine with urates. To answer this question, activity productd ratios of uric acid, sodium urate, and ammonium urate were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of consumption of a 10.4% protein, casein-based (10.4% casein) diet and a 20.8% protein, casein-based (20.8% casein) diet. Significantly lower activity product. ratios of uric acid, sodium urate, and ammonium urate were observed when dogs consumed the 10.4% casein diet. Significantly lower 24-hour urinary excretions of ammonia and phosphorus were observed when dogs consumed the 10.4% casein diet. Twenty-four-hour urinary excretions of magnesium and 24-hour urine pH values were significantly higher when dogs were fed the 10.4% casein diet. These results suggest that use of the 10.4% casein diet in protocols designed for dissolution and prevention of uric acid, sodium urate, and ammonium urate uroliths in dogs may be beneficial.
Cultured pig rhabdomyosarcoma cells with a deletion in the Xq24-qter chromosome region: an immunochemical and cytogenetic characterization
Authors: van der Loop F. T. L. , Bosma A. A. , Vos J. H. , Mirck M. H. , Schaart G. , van den Ingh T. S. G. A. M. , Ramaekers F. C. S.
Published: January 2024

A pig rhabdomyosarcoma cell line (PRUM59) was established, and the immuno(histo)chemical and cytogenetic characterization of these cells was determined. At various swine farms in the Netherlands, pigs were observed that had solitary or multiple skin nodules, which were diagnosed as rhabdomyosarcomas. Cells of a tumor derived from a 3.5-week-old female pig were cultured for immunochemical and cytogenetic analyses. The cell line had characteristic features of undifferentiated muscle cells, similar to those observed in tumor tissue sections; they contained titin, a high-molecular weight protein specific for striated muscle, as dot-like aggregates and as filaments, desmin filaments and cross-striations, smooth muscle actin stress fibers, and vimentin filaments. The cells stained positively for striated muscle actin and tropomyosin as well. The immunohistochemical staining results were supported by results of immunoblotting experiments. Karyotyping of the cells revealed a deletion of a major part of Xq24-qter, a part of the long arm of 1 of the 2 X chromosomes. The other X chromosome and all autosomes appeared to be normal.
Bupivacaine disposition and pharmacologic effects after intravenous and epidural administrations in dogs
Authors: Franquelo Carme , Toledo Alfonso , Manubens Jordi , Cristòfol Carles , Arboix Margarida
Published: January 2024

Pharmacokinetic variables of bupivacaine (bpv) were determined after iv and epidural administrations in the same 6 dogs. Plasma bpv concentration curves after iv administration were adjusted to biexponential kinetics: a rapid distribution phase was followed by a slower elimination phase, with half-life of 34.5 ± 7.8 minutes. Mean plasma clearance was 20.2 ± 7.4 ml/min/kg of body weight, and mean volume of distribution at steady state was 0.7 ± 0.2 L/kg.

After epidural administration, absorption was rapid. Peak plasma concentration, 1.4 ± 0.4 μg/ml, was detected approximately 5 minutes after bpv administration. The half-life corresponding to epidural administration (179 ± 33.6 minutes) was 5 to 6 times longer than that observed after iv administration, possibly because of the slow release of bpv from the epidural space. Induction times were short (2.3 ± 2.2 minutes); anesthesia quickly began and lasted for more than 2 hours (158 ± 48.8 minutes). During that period, bpv plasma concentration ranged between 1.4 and 0.2 μg/mi. Changes in systolic blood pressure and heart rate were correlated to high plasma concentration of bpv. These modifications were observed for the first 30 minutes, reaching baseline values after 60 minutes.
New approach to percutaneous muscle biopsy in dogs
Authors: Reynolds Arleigh J. , Fuhrer Laurent , Valentine Beth A. , Kallfelz Francis A.
Published: January 2024

The size and quality of muscle specimens obtained by use of a percutaneous biopsy technique were studied. All biopsies were performed under local anesthesia, using an 11-gauge biopsy needle. The mean ± sem size of specimens obtained from 128 biopsies of the semitendinosus muscles of 16 Alaskan Huskies was 23.8 ± 4.4 mg. All biopsy specimens were of sufficient quality to permit histochemical differentiation of the fiber types by use of myosin ATPase staining. An additional 8 biopsy specimens were obtained from 1 dog and analyzed for muscle glycogen content. These specimens contained 50.6 ± 7.2 mmol of glucose/kg of muscle wet weight. This modified biopsy procedure was free of notable complications, and repeatable use produced specimens of adequate size and quality for histologic and biochemical analysis. It is concluded that this procedure is a safe and reliable alternative to open biopsy for diagnosis and management of neuromuscular, metabolic, and nutritional myopathies.
Field trial to evaluate immunogenicity of a glycoprotein I (gE)-deleted pseudorabies virus vaccine after its administration in the presence of maternal antibodies
Authors: Weigel Ronald M. , Lehman James R. , Herr Leslie , Hahn Edwin C.
Published: January 2024

A field trial was conducted on a commercial swine farm quarantined because of infection with pseudorabies virus. The purpose was to investigate, in growing pigs born to hyperimmunized sows, the immunogenicity of a vaccine with a glycoprotein I (gE) deletion. One hundred twenty pigs were assigned at random to 1 of 3 vaccination schedules at ages: 8 and 12 weeks; 8, 12, and 14 weeks; and 8,12, and 16 weeks. Immune response was measured at 8, 12, 14, 16, and 18 weeks, using the serum neutralization test, a screening elisa, and assays of IgG and IgA in serum and nasal secretions. Results of the serum neutralization test and the screening elisa indicated that, for pigs vaccinated only at 8 and 12 weeks, the percentage of pigs with pseudorabies virus serum antibodies decreased substantially by 18 weeks; for pigs given a booster at 14 or 16 weeks, the prevalence of serum antibodies at 18 weeks was higher, with 16-week booster vaccination eliciting the best response. At each age, nasal IgA and IgG values were highly correlated (r ≥ 0.70), as were serum IgA and IgG values; correlations of serum with nasal IgA and IgG values were somewhat lower (approx range, r = 0.40 to 0.70). Nevertheless, an increase in serum IgA or IgG values on vaccination was no guarantee of an increase in nasal IgA or IgG values. For serum and nasal mucosal antibodies, a poor immune response was associated with high quantities of maternally derived antibodies. Vaccination at 16 weeks was necessary to ensure eliciting of an immune response in almost all pigs.
Effects of short-term restraint stress on plasma concentrations of catecholamines, β-endorphin, and cortisol in gilts
Authors: Roozen Antoine W. M. , Tsuma Victor T. , Magnusson Ulf
Published: January 2024

The effects of short-term restraint stress, by means of snaring, on plasma concentrations of catecholamines, β-endorphin, and cortisol were studied in 6 gilts. A catheter was inserted into the jugular vein, and 2 blood samples were collected before onset of stress. Thereafter, a hog snare was applied, and blood samples were collected at 0.5,2, and 3.5 minutes after the start of snaring. Plasma epinephrine and norepinephrine concentrations increased (P < 0.001) within 0.5 minute after start of restraint and decreased thereafter. Plasma concentration of β-endorphin increased (P < 0.05) within 2 minutes after start of restraint, whereas that of cortisol increased (P < 0.05) 3.5 minutes after start of restraint. Taken together, short-term stress, such as snaring, may increase the plasma concentration of catecholamines, β-endorphin, and cortisol in pigs.
Isolation of Mycobacterium paratuberculosis from colostrum and milk of subclinically infected cows
Authors: Streeter Robert N. , Hoffsis Glen F. , Bech-Nielsen Steen , Shulaw William P. , Rings D. Michael
Published: January 2024

Mycobacterial culture was performed on colostrum, milk, and feces from 126 clinically normal cows of a single herd with high prevalence of Mycobacterium paratuberculosis infection. Thirty-six (28.6%) cows were determined to be shedding the organism in the feces. Of the 36 fecal culture-positive cows, M paratuberculosis was isolated from the colostrum of 8 (22.2%) and from the milk of 3 (8.3%). Cows that were heavy fecal shedders were more likely to shed the organism in the colostrum than were light fecal shedders.
Effect of treatment with a monoclonal antibody against equine tumor necrosis factor (TNF) on clinical, hematologic, and circulating TNF responses of Miniature Horses given endotoxin
Authors: Cargile Jana L. , MacKay Robert J. , Dankert John R. , Skelley Leslie
Published: January 2024

Tumor necrosis factor-α (tnf) is an important mediator of endotoxin-induced pathologic changes. To help define the role of tnf in equids with endotoxemia, the effects of pretreatment with a murine monoclonal antibody (mab) against equine tnf were evaluated in Miniature Horses given endotoxin. Five horses were given tnf mab at a dosage of 1.86 mg/kg of body weight, iv, and 5 were given control mab. Five minutes later, lipopolysaccharide (lps; Escherichia coli O55:B5), 0.25 µg/kg, was given to all horses by bolus iv infusion. Clinical signs of disease were monitored at intervals up to 24 hours after lps infusion, and blood was taken for determination of hematologic and clinical responses of horses given wbc count, pcv, plasma total protein concentration, plasma tnf activity, and serum mab concentration. Reduction of plasma tnf activity in anti-tnf-treated horses was highly significant (P < 0.001), compared with that in control horses. Horses given tnf mab had significantly improved clinical abnormality score (P < 0.010), lower heart rate (P < 0.001), and higher wbc count (P < 0.001), compared with horses given control mab. Rectal temperature, respiratory rate, pcv, and plasma total protein concentration were not significantly different between groups. Serum mab concentration peaked at 68 µg/ml 30 minutes after the end of antibody infusion in both groups. Neutralization of lps-induced tnf activity reduced the hematologic and clinical responses of horses given lps iv.