bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual nematocidal effectiveness of ivermectin in cattle
Authors: Yazwinski T. A. , Featherston H. , Tucker C. , Johnson Z. 
Published: January 2024

Summary
We assessed the duration of ivermectin persistence by measuring posttreatment nematocidal effectiveness; topical and injectable formulations of ivermectin were evaluated. Thirty-five nematode-free calves were randomly allocated to 1 of 5 treatment groups (7 calves/group). The treatment (Trt) group designations were: Trt 1, nonmedicated; Trt 2, injectable ivermectin administered at the rate of 0.2 mg/kg of body weight on day 0; Trt 3, injectable ivermectin administered at the aforementioned rate, but on day 7; Trt 4, topically administered ivermectin at the rate of 0.5 mg/kg on day 0; and Trt 5, topically administered ivermectin at the aforementioned rate, but on day 7. All calves were subsequently given infective larvae of Haemonchus, Cooperia, Trichostrongylus, and Oesophagostomum spp on day 21. One week later, each calf was additionally administered infective larvae of Dictyocaulus and Ostertagia spp. Trial calves were euthanatized on trial days 49 to 52 for nematode quantitation. On the basis of geometric mean comparisons, total nematode burdens were reduced from control group counts by 98.9 and 86.3% for calves treated on days 7 and 0 with injectable formulations, respectively, and 97.2 and 64.7% for calves treated on days 7 and 0 with pour-on formulations, respectively. Trichostrongylus colubriformis infections were most refractory to the persistent activity of ivermectin, with H placei also proving to be persistence limiting. All treatments were easily administered, and adverse behavioral or tissue reactions were not observed.
Evaluation of total serum bile acids concentration and bile acid profiles in healthy cats after oral administration of ursodeoxycholic acid
Authors: Day Deborah G. , Meyer Dennis J. , Johnson Susan E. , Weisbrode Steven E. , Thudium Douglas T. , Rhodes Diane C. 
Published: January 2024

Summary
Ursodeoxycholic acid (udca; 10 mg/kg of body weight) was administered orally to 5 healthy cats for 3 months. Signs of illness were not apparent in any cat during treatment with udca. Results of monthly CBC, serum biochemical analysis, and urinalysis were unchanged during drug administration. There was a decrease in serum cholesterol concentration in 4 cats. Total postprandial serum bile acids (ppsba) concentration was significantly (P = 0.0003) increased over total preprandial serum bile acids (prsba) concentration at all sample collection periods. The PRSBA and PPSBA concentrations were significantly (P < 0.05) increased at all sample collection periods after administration of udca, compared with baseline values. Ursodeoxycholic and tauroursodeoxycholic acids were not detected in serum prior to initiating administration of udca. Both bile acids were detected in the serum of all cats 1 and 2 months after udca administration and were detected in the serum of 2 cats 3 months after initiating UCDA administration. Hepatic ultrasonographic findings were normal before and after completion of udca administration. A mild, focal lymphocytic infiltrate was observed in 3 cats 3 months after initiating udca administration. Results of the study indicate that udca is absorbed into the systemic circulation of cats after oral administration, undergoes hepatic conjugation, and appears to be safe.
Rate of change of QT interval in response to a sudden change in the heart rate in dogs
Authors: Oguchi Yoko , Hamlin Robert L. 
Published: January 2024

Summary
Although it is known that the QT interval is dependent on the preceding RR interval, QT interval does not vary during respiratory sinus arrhythmia, despite a wide variation in heart rate. To assess the rate of change of the QT interval following an abrupt increase or decrease in heart rate, QT intervals were measured from ecg of healthy, anesthetized, thoracotomized dogs in which a junctional rhythm had been induced by destroying the sinoatrial node. Atria were paced at 800- or 600 -millisecond cycle durations until a steady state was reached, and then the cycle duration was changed suddenly to a new cycle duration (600 or 800 milliseconds, respectively). The time and number of heart beats required until the QT interval achieved a value of 63% (1 time constant) of the new steady state were calculated. Time constants for change in QT interval vs the number of beats following the change were 2.8 (sd = 1.3 s) seconds when heart rate was accelerated and 4.7 (sd = 2.1 s) seconds when heart rate was slowed. Differences were not statistically significant. The time constants for change in QT interval duration vs duration after the sudden change in heart rate were 1.7 (sd = 0.8 s) seconds when heart rate was accelerated and 3.7 (sd = 1.7 s) seconds when heart rate was slowed. These time constants differed significantly (P < 0.01). Response of QT interval, therefore, depended on the number of heart beats following sudden change in heart rate, but not time, except as time determined the number of heart beats. The QT interval did not change until 3 to 5 beats after the heart rate was suddenly changed. This number of beats would be more than that which would occur in 1 respiratory cycle in dogs; therefore, QT interval memory would prohibit changes in QT intervals that occur during respiratory sinus arrhythmia.
Critical appraisal of pressure-frequency relation for estimation of diaphragm function in conscious calves
Authors: Desmecht Daniel J.-M. , Linden Annick S. , Lekeux Pierre M. 
Published: January 2024

Summary
A method yielding functional diaphragmatic variables in conscious animals is crucially needed to determine whether concepts and conclusions drawn from deeply anesthetized, highly instrumented clinically normal animals can be extrapolated to patients. Transdiaphragmatic pressure (Pdi) was, therefore, measured in 20 conscious calves during supramaximal transvenous bilateral stimulations of the phrenic nerves (pulse duration, 0.2 milliseconds; pulse frequency, 1, 10, 20, 30, 40, 70, and 100 Hz). Constancy of phrenic activation and precontraction length and geometry was ensured by respectively monitoring the amplitudes of right and left mass action potentials and triggering each activation train at end-expiratory lung volume against an occluded airway. Repeated phrenic activation and pressure recording procedures were well tolerated, safe, specific, and able to achieve constant and symmetric diaphragmatic tetanic contractions for prolonged periods. The Pdi increased with frequency of stimulation, so that, at 10, 20, 40, and 70 Hz, the mean ± sd generated Pdi was 33 ± 5, 65 ± 8, 82 ± 6, and 94 ± 6% of Pdi at 100 Hz, respectively. The general shape of the Pdi-frequency relation and the absolute values of the generated Pdi were reproducible at 10-hour intervals despite CO2- or resistor-induced substantial changes in breathing pattern. It is concluded that this experimental model provides a reliable assessment of diaphragm function in conscious animals and can be used to study diaphragmatic contractility.
Immunomodulatory effects of staphylococcal antigen and antigen-antibody complexes on canine mononuclear and polymorphonuclear leukocytes
Authors: DeBoer Douglas J. 
Published: January 2024

Summary
Staphylococcal antigens and immune complexes (ic) prepared from antigen and hyperimmune canine serum were tested for their effects on certain functions of mononuclear (mn) and polymorphonuclear (pmn) leukocytes (cells) obtained from healthy dogs. The effect on mn cells was studied by determining the ability of antigen or ic to augment or inhibit mitogenesis induced by phytohemagglutinin (pha). The effect of antigen or ic on pmn cells was studied by measurement of H2O2 production as an indicator of respiratory burst. Neither the antigen nor the ic, when cultured with mn cells, was mitogenic. Coincubation of antigen or ic with mn cells and pha resulted in a concentration-dependent decrease in mitogenesis. The decreased mitogenesis could not be overcome by addition of excess pha, and may in part have been related to toxic effects of the antigen or ic on mn cells. When mn cells were instead preincubated with antigen or ic, then washed and stimulated with pha, there was still a concentration-dependent inhibition of mitogenesis, although toxicity to the cells was not observed. Low concentrations of staphylococcal antigen or IC stimulated slight H2O2 production by pmn cells. When pmn cells were co-incubated with ic and another stimulus (opsonized zymosan or phorbol myristate acetate), ic appeared to augment phorbol myristate acetate-, but not zymosan-induced stimulation. These results suggest that staphylococcal antigens, either alone or complexed with antibody, have the ability to stimulate pmn cells and inhibit mn cell function. Such actions may have a role in the pathogenesis of recurrent staphylococcal infection in canine patients.
Characterization of a pseudorabies virus that is defective in the early protein 0 and latency genes
Authors: Cheung Andrew K. , Fang Jing , Wesley Ronald D. 
Published: January 2024

Summary
A recombinant pseudorabies virus that is defective in the early protein 0 (EP0) and large latency transcript (LLT) genes was constructed. A portion of the EP0 and LLT genes was replaced by the lacZ gene of Escherichia coli that had been placed under the control of the pseudorabies virus gX gene promoter. This recombinant virus produces smaller size plaques and yields less virus than does the parent virus on Madin-Darby bovine kidney cells. Although the time course of virus replication and release into the medium of the recombinant and parent viruses are similar, the recombinant virus did not reach as high a titer. Similar to the parent virus, the recombinant virus replicates in the upper segment of the respiratory tract of swine, but the amount of progeny viruses produced is significantly reduced. The data indicated that the EP0 and LLT genes of pseudorabies virus are nonessential for replication. Virus that lacks these 2 genes has impaired growth in tissue culture and is attenuated for swine, compared with the parent virus.
Characterization of a murine monoclonal antibody generated against Neospora caninum tachyzoites by use of western blot analysis and immunoelectron microscopy
Authors: Cole Rebecca A. , Lindsay David S. , Dubey J. P. , Toivio-Kinnucan Maria A. , Blagburn Byron L. 
Published: January 2024

Summary
A murine monoclonal antibody (mab) 6G7 generated against tachyzoites of Neospora caninum recognized 8 major and several minor antigens, as observed by western blot analysis. Relative rate of migration of the 8 major antigens ranged from 31 to 97.4 kd. In addition, mab 6G7 recognized a Toxoplasma gondii tachyzoite antigen with a relative rate of migration of 107 kd. Immunogold labeling of N caninum tachyzoites grown in human foreskin fibroblast cells indicated that mab 6G7 binds to micronemes, dense granules, basal portions of rhoptries, and intravacuolar tubules within the parasitophorous vacuole. Monoclonal antibody 6G7 also bound to micronemes and basal portions of rhoptries within tachyzoites of T gondii. Monoclonal antibody 6G7 did not significantly inhibit development of tachyzoites in vitro.
Effect of topically applied 2% pilocarpine and 0.25% demecarium bromide on blood-aqueous barrier permeability in dogs
Authors: Krohne Sheryl Greve 
Published: January 2024

Summary
The effect of topically applied 2% pilocarpine and 0.25% demecarium bromide on aqueous humor flare was evaluated while treating normal eyes of dogs 3 times daily for 8 days. Fifteen clinically normal Beagles were allotted to 2 drug treatment groups, and flare was measured/using laser flaremetry. Pilocarpine caused an increase of flare to 167 photon counts (pc)/ms at 7 hours, compared with the nontreated control eye mean value 3.7 pc/ms. By 31 hours, flare had decreased to 70 pc/ms with 3 daily topical treatments. By 55 hours, the flare measurement was in the normal range. Intraocular pressure (iop) decreased in the treated eyes, compared with the non-treated eyes, and maximal decrease in iop was observed at the same time as maximal flare. Demecarium induced a similar increase in flare and decrease in iop, with peak effect seen at 31 hours. At that time, the flaremetry result was 28 pc/ms, compared with 3.4 pc/ms in the nontreated control eyes. After 8 days of 3 times daily treatment, flare values had returned to normal in eyes of dogs in both treatment groups. The transient increase in aqueous humor protein concentration did not result in ocular or visual damage, and long-term changes were not seen. The amount of flare increase attributable to topical application of pilocarpine was greater than the increase in human eyes when measured by use of laser flaremetry.
Effect of succinylcholine, diazepam, and dantrolene on the urethral pressure profile of anesthetized, healthy, sexually intact male cats
Authors: Straeter-Knowlen Ingrid M. , Marks Steven L. , Speth Robert C. , Wirth W. , Knowlen Grant G. 
Published: January 2024

Summary
Effects of the neuromuscular blocking agent succinylcholine (n = 9), the centrally acting skeletal muscle relaxant diazepam (n = 11), and the direct-acting skeletal muscle relaxant dantrolene sodium (n = 8) on the urethral pressure profile were evaluated in anesthetized, healthy, sexually intact, adult male cats. Intravenous administration of succinylcholine (0.075 mg/kg of body weight) significantly decreased mean absolute pressure in the prostatic and post-prostatic/penile intraurethral segments by −9.5 and −6.5 mm of Hg, respectively (P = 0.0002 and P = 0.0006, respectively). Dantrolene (1.0 mg/kg, iv) significantly decreased mean prostatic and postprostatic/penile intraurethral segmental pressures by −3.5 and −2.8 mm of Hg, respectively (P = 0.005 and P = 0.0181, respectively). Diazepam (0.8 mg/kg, iv) did not significantly alter mean intraurethral segmental pressures. None of the drugs caused a change in segmental lengths of the urethra. These results indicate that skeletal muscle makes a substantial contribution to intraurethral tone in anesthetized, healthy, sexually intact male cats and that skeletal muscle relaxation may be successful in reducing prostatic and post-prostatic/penile urethral segmental tone in male cats. These results also suggest that dantrolene sodium may be valuable for the pharmacologic management of urethral disorders in male cats.
Comparison of ethanol and 4-methylpyrazole as treatments for ethylene glycol intoxication in cats
Authors: Dial Sharon M. , Thrall Mary Anna Hull , Hamar Dwayne W. 
Published: January 2024

Summary
The efficacy of 4-methylpyrazole (4-mp) and ethanol as treatment for ethylene glycol (eg) intoxication in cats was compared. Twenty-two cats were assigned at random to 6 experimental groups. Cats of 1 experimental group were given only 4-mp; those of another experimental group were given only eg. Cats of 3 experimental groups were intoxicated with eg and given 4-mp at 0 hour or 2 or 3 hours after eg ingestion, and those of 1 experimental group were given eg and treated with ethanol 3 hours after eg ingestion. Physical, biochemical, hematologic, blood gas, serum and urine eg concentrations, and urinalysis findings were evaluated at 0, 1, 3, 6, 9, 12, 24, 48, and 72 hours, 1 week, and 2 weeks after eg ingestion or 4-mp treatment in cats of the 4-mp only group. The half-life of eg and percentage of ingested eg excreted unchanged were determined for each group.
4-Methylpyrazole treatment at 0 hour was most effective at preventing metabolism of eg. 4-Methylpyrazole was not effective in preventing development of renal failure when given 2 or 3 hours after eg ingestion. Ethanol given 3 hours after eg ingestion was successful in preventing development of renal dysfunction in 2 of the 6 cats treated 3 hours after eg ingestion. Of the remaining 4 cats treated with ethanol, 2 developed transient renal dysfunction and 2 developed acute oliguric renal failure and were euthanatized.
4-Methylpyrazol given 2 or 3 hours after eg ingestion was less effective in preventing eg metabolism than was ethanol given 3 hours after eg ingestion. Therefore 4-mp, at the dose found to be effective in dogs, cannot be recommended as an alternative to ethanol for treatment of eg intoxication in cats.
Effect of exercise intensity on plasma prostaglandin concentrations in horses
Authors: Mitten L. A. , Hinchcliff K. W. , Pate J. L. , Kohn C. W. , McKeever K. H. 
Published: January 2024

SUMMARY
Exertion has an effect on plasma, serum, and/or urine prostanoid concentrations in many species. We investigated the effect of exercise intensity on plasma prostaglandin concentrations during and after exercise in horses. Six Thoroughbreds completed 4 trials: 3 exercise trials (low-, medium-, and high-speed) and 1 nonexercise (control) trial on a high-speed treadmill. Blood samples were collected from a jugular catheter before, during, and after exercise. The pcv and blood lactate, plasma protein, plasma prostacyclin (6-keto-pgf1α), thromboxane B2 (txb2), and prostaglandin E2 (pge2) concentrations were measured before, during, and after exercise. Exercise significantly (P = 0.001) increased plasma txb2 concentration during and after exercise in the low-, medium-, and high-speed trials, although effect of exercise intensity was not detected. Exercise was associated with an increase in pcv and blood lactate and plasma protein concentrations. There was no effect of exercise on plasma 6-keto-pgf1α concentrations; pge2 was not detected in plasma from any horse in any trial.
Cardiorespiratory effects of acepromazine maleate and buprenorphine hydrochloride in clinically normal dogs
Authors: Stepien Rebecca L. , Bonagura John D. , Bednarski Richard M. , Muir William W. 
Published: January 2024

SUMMARY
Cardiorespiratory effects of the combination of acepromazine maleate (acp) and buprenorphine hydrochloride (bpn) were studied in 11 healthy, conscious dogs. Values for systemic and pulmonary artery blood pressure, cardiac output, arterial and venous pH and blood gas tensions, and invasive and noninvasive estimates of ventricular systolic function, preload, and afterload were obtained before sedation and after administration of each drug. Acepromazine maleate (0.1 mg/kg, iv) depressed cardiac function, compared with baseline values for unsedated dogs. Cardiac output decreased from a mean (± sd) value of 4.2 (± 1.5) L/min to 3.1 (± 0.8) L/min (P < 0.001), a change not attributed to heart rate. Pulmonary capillary wedge pressure decreased from 8.3 (± 4.2) mm of Hg to 6.5 (± 4.3) mm of Hg (P < 0.01), but mean right atrial pressure did not change. Left ventricular measurement of the maximal positive rate of pressure change (dP/dtmax) decreased from 2,668 (± 356)/mm of Hg/s to 2,145 (± 463) mm of Hg/s (P < 0.001), and ventricular stroke volume decreased from 43.2 (± 15.2) ml/beat to 32.3 (± 8.6) ml/beat. Noninvasive indices of left ventricular function, ventricular shortening fraction, peak aortic velocity, and aortic average acceleration were decreased after acp administration, but were not statistically different from baseline values. Mean systemic arterial blood pressure decreased from 121 ± 12 mm of Hg to 96 ± 13 mm of Hg 15 minutes after acp administration (P < 0.001). Total systemic vascular resistance was not significantly different from the baseline value. Sequential administration of cumulative doses of bpn (0.005, 0.01, and 0.1 mg/kg of body weight, iv), initiated 15 minutes after administration of acp, did not cause statistically significant depression of hemodynamic variables, except for heart rate, which decreased after bpn, and left ventricular dP/dtmax, which decreased slightly at the highest dose of bpn. Small, clinically insignificant changes in blood pH, venous bicarbonate concentration, and Paco2 were observed after administration of acp and bpn. Respiratory rate decreased from 60 ± 48 breaths/min to 24 ± 12 breaths/min, and sedation level was significantly (P < 0.05) increased from baseline values by administration of acp. Sedation level was further increased by administration of bpn at the lowest dose (P < 0.05). The combination of acp and bpn resulted in good to excellent sedation, but depressed ventricular function; however, most of the hemodynamic effects could be attributed to administration of acp and withdrawal of sympathetic activity.
Cardiopulmonary responses in healthy dogs during endoscopic examination of the gastrointestinal tract
Authors: Jergens Albert E. , Riedesel Dean H. , Ries Philip A. , Miles Kristina G. , Bailey Theodore B. 
Published: January 2024

SUMMARY
Cardiopulmonary responses were evaluated in 12 dogs undergoing endoscopy (gastroscopy and enteroscopy). Constant endoscopic insufflation was used to distend the stomach and small intestine for 30 minutes in groups of small (< 10 kg; n = 4), medium (10 to 20 kg; n = 4), and large (> 20 kg; n = 4) dogs. Cardiopulmonary measurements within groups prior to gastric distention (preendoscopy) were compared with postendoscopy measurements and with those made during endoscopy. After distending the stomach and small intestine, increased luminal pressure within the body of the stomach and in the descending duodenum (P < 0.05) and increased abdominal girth (P < 0.05) were observed, with the greatest changes in small dogs. Caudal vena cava pressures and mean arterial and pulmonary artery pressures increased (P < 0.05) during endoscopy. Cardiac index varied, with small dogs having greater cardiac index (P < 0.05) during endoscopy, compared with that in medium and large dogs. Minute volume remained unchanged during insufflation, despite a decrease in tidal volume (P < 0.05), because of an increase in respiratory rate (P < 0.05). Arterial blood gas analysis revealed a mild, mixed metabolic/respiratory acidosis in all groups. Although cardiopulmonary changes associated with gastrointestinal tract endoscopy were common, the changes were often small and of little clinical significance.
Administration of recombinant human interleukin 1 receptor antagonist during endotoxin-induced mastitis in cows
Authors: Shuster D. E. , Kehrli M. E. 
Published: January 2024

SUMMARY
The role of interleukin 1 (il-1) as an inflammatory mediator during mastitis and the therapeutic effect of recombinant human il-1 receptor antagonist (il-1ra) for bovine mastitis was studied. Cows were intramammarily infused with lipopolysaccharide (25 μg) in 1 mammary gland. Half the cows also received infusions of 5 mg of il-1ra into the same mammary gland just prior to endotoxin infusion and 4, 8, and 12 hours later. After endotoxin infusion, tumor necrosis factor and high il-1 bioactivity were detected in whey from infused glands. Vascular permeability changes and neutrophil accumulation in milk paralleled the appearance of cytokines. A systemic reaction, characterized by pyrexia and an increase in blood cortisol concentration, also were observed. Milk yield was inhibited and milk composition was altered in infused and noninfused glands. The increase in il-1 bioactivity in milk after endotoxin infusion was almost completely prevented in glands receiving il-lra. However, il-lra had no effect on local inflammation, systemic reaction, or impairment in productive performance. These results indicate that il-1 does not mediate its effect within the milk compartment, and suggest either that il-1 is not critical to the mastitic response or that intramammary infusion of il-1ra does not place the antagonist where il-1 interacts with its receptor.