bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of phenytoin on isoproterenol-induced myocardial fibrosis in rats
Authors: Besbasi Faiza S. , Hamlin Robert L.
Published: January 2024

A study was designed to determine whether phenytoin (phe) prevents the myocardial necrosis and subsequent fibrosis produced by isoproterenol (iso). Seven groups of female rats of the Wistar strain were used. Rats in groups 1 and 5 served as controls, Rats in group 3 were injected sc with 85 mg of iso/kg of body weight for 2 consecutive days. Rats in groups 2 and 6 received 100 mg of phe/kg orally. Rats in groups 4 and 7 received both PHE and iso. There were 6 to 9 rats/group. Effects of iso and phe were evaluated gravimetrically, histologically, and electrocardiographically. Heart weight/body weight ratios for each group receiving iso, with or without phe, were greater than for groups not receiving iso (P < 0.05). Light microscopic examination of heart sections of rats given iso alone or iso + phe revealed multiple and diffuse areas of fibrosis. Fibrosis in hearts from rats receiving phe + iso was less severe than that in hearts from rats receiving iso alone, but the difference was not statistically significant. Electrocardiographic changes of statistical significance were not observed in rats receiving any compound (alone or in combination), when compared with the control groups of equal age.
Effects of Mycoplasma hyopneumoniae and Actinobacillus (Haemophilus) pleuropneumoniae infections on alveolar macrophage functions in swine
Authors: Caruso J. P. , Ross R. F.
Published: January 2024

Alveolar macrophages were collected at necropsy from pigs inoculated with Mycoplasma hyopneumoniae or Actinobacillus pleuropneumoniae or both and were tested for phagocytic capabilities, using in vitro techniques. Macrophages from noninoculated littermates were used as controls. Alveolar macrophages from pigs inoculated with either M hyopneumoniae or A pleuropneumoniae had significantly (P < 0.05 to P < 0.0025) higher phagocytic capacity than that of noninoculated controls. Macrophages from A pleuropneumoniae-inoculated pigs were comparatively more stimulated than were those from M hyopneumoniae-inoculated pigs. Pigs inoculated with M hyopneumoniae and then challenge-exposed with A pleuropneumoniae 2 and 4 weeks later had greatly reduced phagocytosis. Infection with M hyopneumoniae or A pleuropneumoniae caused stimulation of alveolar macrophage functions, and M hyopneumoniae infections may have suppressed phagocytic responses when pigs were challenge-exposed with a secondary pathogen (A pleuropneumoniae). This potential suppression may represent a prediposition of the host by M hyopneumoniae to secondary bacterial infections.
Reactivation of latent pseudorabies virus infection in vaccinated commercial sows
Authors: Cowen Peter , Li Shugen , Guy James S. , Erickson Gene A. , Blanchard Decatur
Published: January 2024

Pseudorabies virus (prv) was isolated from 9 of 44 prv-vaccinated seropositive sows on 5 of 11 farms. Although serum-neutralization antibody titers were 1:16 to 1:256, 28 virus isolates were obtained from tonsil, nasal, or buccal swab samples from 9 sows given 2 ml of dexamethasone/kg of body weight im for 5 days. Pseudorabies virus was isolated from 6 of 20 sows (3 of 5 farms) given a killed-virus vaccination. Virus was obtained from 3 of 24 sows (2 of 6 farms) given modified-live virus and killed-virus vaccination.

Evaluation of the 9 prv with 5 restriction endonucleases revealed 4 prv existing genotypes. The 9 isolated types of prv appeared to be indistinguishable by Kpn I and BamHI restriction endonuclease analysis; however, when analyzed with Sal I, HinfI, and Pst I, isolates 7 (farm D), 8 (farm C), and 9 (farm B) had numerous differences. Isolates 1, 2, 3, and 4 (farm F) and 5 and 6 (farm G) appeared to be the same genotype when further analyzed with Pst I, HinfI, and Sal I.
Renal excretion of creatinine, electrolytes, protein, and enzymes in healthy sheep
Authors: Garry Franklyn , Chew Dennis J. , Rings D. M. , Tarr M. J. , Hoffsis Glen F.
Published: January 2024

Urinary indices of renal function and damage were measured in 6 healthy, mature ewes over a 48-hour period. Endogenous creatinine clearance, total and fractional electrolyte excretion rates, protein excretion, urine volume, and urine γ-glutamyltransferase and β-glucuronidase activities were measured. Significant variations in the excretion rates of creatinine, electrolytes, and protein were not found between intervals within the 48-hour urine collection period. Total urinary electrolyte excretion rates were significantly (P < 0.001) correlated with fractional electrolyte excretion rates normalized for creatinine concentration; however, coefficient of determination was low.
Effects of age, sex, and body size on serum concentrations of thyroid and adrenocortical hormones in dogs
Authors: Reimers Thomas J. , Lawler Dennis F. , Sutaria Perry M. , Correa Maria T. , Erb Hollis N.
Published: January 2024

Thyroxine (T4), 3,5,3′-triiodothyronine (T3), and cortisol frequently are quantified in canine serum or plasma samples to aid in the diagnosis of hypothyroidism, hypoadrenocorticism, and hyperadrenocorticism. Many laboratories have established reliable references values for concentrations of these hormones in blood of clinically normal animals. However, nonpathologic factors that affect thyroidal and adrenocortical secretion may lead to misinterpretation of test results when values for individual animals are compared with reference values. The objective of the study reported here was to identify effects of age, sex, and body size (ie, breed) on serum concentrations of T3, T4, and cortisol in dogs.

Blood samples were collected from 1,074 healthy dogs, and serum concentrations of the iodothyronines and cortisol were evaluated for effects of breed/size, sex, and age. Mean (± sem) serum concentration of T4 was greater in small (2.45 ± 0.06 μg/dl)- than in medium (1.94 ± 0.04 μg/dl)- or large (2.03 ± 0.03 μg/dl)-breed dogs, the same in females (2.11 ± 0.04 μg/dl) and males (2.08 ± 0.04 μ/dl), and greater in nursing pups (3.04 ± 0.05 μg/dl) than in weanling pups (1.94 ± 0.05 μg/dl), rapidly growing dogs (1.95 ± 0.04 μg/dl), and young adult (1.90 ± 0.06 μg/dl), middle-aged adult (1.72 ± 0.05 μg/dl), or old adult (1.50 ± 0.05 μg/dl) dogs. Dogs > 6 years old had lower mean serum T4 concentration than did dogs of all other ages, except middle-aged adults. Mean serum T3 concentration in medium-sized dogs (1.00 ± 0.01 ng/ml) was greater than that in small (0.90 ± 0.01 ng/ml)- and large (0.88 ± 0.01 ng/ml)-breed dogs. Serum T3 concentration was lowest in nursing (0.85 ± 0.01 ng/ml) and weanling (0.77 ± 0.02 ng/ml) pups, increased in rapidly growing dogs (0.99 ± 0.01 ng/ml) and young adult dogs (1.10 ± 0.04 ng/ml), and decreased slightly in middleaged (0.98 ± 0.02 ng/ml) and old (1.01 ± 0.03 ng/ml) adult dogs. Serum T3 concentration was unaffected by sex. Mean serum cortisol concentration was greater in small (1.06 ± 0.07 μg/dl)- than in large (0.79 ± 0.03 μg/ dl)-breed dogs. Serum from nursing pups (0.57 ± 0.04 μg/ dl) contained less cortisol than did serum from older dogs (mean values ≥ 0.92 μg/dl). Serum cortisol concentration was not different between males and females. These effects of breed/size and age on serum T3, T4, and cortisol concentrations should be considered when evaluating thyroid and adrenocortical functions in dogs.
Comparison of the complement-fixation and agar gel immunodiffusion tests for diagnosis of subclinical bovine paratuberculosis
Authors: Sherman David M. , Gay John M. , Bouley Diane S. , Nelson Glen H.
Published: January 2024

The performance of the serum complement fixation (cf) test was compared with that of a serum agar gel immunodiffusion (agid) test on 74 subclinically infected and 154 uninfected cattle in 6 commercial midwestern dairy herds with Mycobacterium paratuberculosis infection and on 30 cattle in a herd that was free of infection. Infection status of cattle within herds was established by performance of a series of 3 or more fecal cultures and of ileocecal lymph node cultures of culled cattle.

In cattle with subclinical infection detected by culturing, the sensitivity estimates of the cf and agid tests were 10.8% (3.6% se) and 18.9% (4.5% se), respectively, In the cattle classified as disease free, the specificity estimates of the cf and agid tests were 97.4% (1.3% se) and 99.4% (0.6% se), respectively. Neither set of estimates was significantly different.

Negative test results obtained with the use of either test in apparently normal cattle from suspect herds should be interpreted with caution because both tests suffer from how sensitivities in subclinically infected animals. However, the agid test may be more useful in regulatory situations in which the cf test is currently used because the agid test is easier to perform and to interpret.
Biological effects of staphylococcal protein A immunotherapy in cats with induced feline leukemia virus infection
Authors: Lafrado Louis J. , Mathes Lawrence E. , Zack Philip M. , Olsen Richard G.
Published: January 2024

Biological effects of staphylococcal protein A (spa) immunotherapy were studied in 5 viremic and 6 nonviremic cats with induced FeLV infection and in 6 control cats. The spa therapy neither reversed FeLV viremia nor resulted in consistent improvement in humoral immune responses to FeLV antigens. However, spa immunotherapy induced a proliferative response in bone marrow granulocytic lineage, possibly resulting in expression of FeLV-free mature neutrophils in the blood. Seemingly, viral burden and chemiluminescent responses were reversed in viremic cats during spa immunotherapy.
Influence of tolazoline on caudal epidural administration of xylazine in cattle
Authors: Skarda Roman T. , Jean Guy St. , Muir William W.
Published: January 2024

Eight adult female cattle (6 Holstein, 1 Jersey, 1 Brown Swiss) were used to determine the antagonistic effects of tolazoline, an α2-adrenoceptor antagonist, on xylazine-induced (via caudal epidural administration) depression of cns, respiratory, and cardiovascular activity and rumen motility. A 2% solution of xylazine HCl was injected into the epidural space at the first coccygeal interspace, using a dosage of 0.05 mg/kg of body weight, diluted to a 5-ml volume with sterile water, and administered at a rate of approximately 1 ml/30 s. Eight minutes after xylazine injection, either tolazoline (0.3 mg/kg) or saline solution (4 ml) was administered iv. All 8 cattle were treated, using both regimens in a random sequence; at least 1 week elapsed between treatments. Epidurally administered xylazine induced caudal analgesia (S3 to coccyx), as evaluated by no response to superficial and deep muscular pinprick, and induced sedation, cardiopulmonary depression, and inhibition of rumen motility, but all cattle remained standing. Tolazoline effectively reversed xylazine-induced rumen hypomotility, and partially antagonized xylazine-induced cardiopulmonary depression without affecting sedation and desirable local (S3 to coccyx) analgesic effects.
Effect of age and training status on pharmacokinetics of flunixin meglumine in Thoroughbreds
Authors: Jensen R. C. , Fischer J. H. , Cwik M. J.
Published: January 2024

The effect of age and training status on the pharmacokinetics of flunixin meglumine was evaluated in 16 Thoroughbreds. Horses were assigned to 1 of 3 groups on the basis of age and training status: group A (n = 6), horses in active training and ≤ 5 years old; group B (n = 5), horses out of training for a minimum of 6 weeks and ≤ 5 years old; and group C (n = 5), horses out of training for at least 2 years and ≥ 9 years old. After administration of 500 mg of flunixin meglumine iv, multiple serum and urine samples were obtained over 24 hours and assayed for flunixin by high-performance liquid chromatography. Although the mean distribution rate constant and volume of distribution were similar for the 3 groups, mean total body clearance and elimination rate constant were significantly (P < 0.05) greater and half-life significantly (P < 0.01) less in groups A and B, compared with group C. Differences in pharmacokinetic values were not observed between the horses in groups A and B. In addition, the changes in clearance, elimination rate constant, and half-life of flunixin were found to significantly (P < 0.05) correlate with age. The results of this investigation indicated that age, but not training status, influences disposition of flunixin meglumine in Thoroughbreds.
Antibodies to bovine parvovirus acquired by neonatal pigs through ingestion of virus and antibody in the diet
Authors: Mengeling W. L. , Matthews P. J.
Published: January 2024

The ability of pigs to respond immunologically to ingestion of bovine parvovirus (bpv) was tested by feeding 4 cesarean-derived, colostrum-deprived (cdcd) pigs a live virus-contaminated, liquid diet for the first 4 weeks of life. Virus-neutralizing (vn) antibodies were detected in the serum of 2 of the 4 pigs when they were 4 weeks old. Antibody titer remained at about the same level for several weeks, then decreased during the remainder of the 29-week interval of testing. The relative reactivity of these sera based on results of indirect immunofluorescence paralleled the corresponding vn titer. Neither of the other 2 pigs exposed to bpv had any appreciable immune response. The potential for passive acquisition of antibody from the diet was tested by feeding 4 other cdcd pigs bovine colostrum containing antibodies to bpv and bovine viral diarrhea virus (bvdv) for the first 2 days of life. All had serum vn antibodies for both viruses when they were tested at 2 days of age. The decay rate of the heterologous, passively acquired antibody was approximately linear; however, antibody half-life was relatively short, about 3.5 days, and titers were no longer detectable when pigs were 4 weeks (bpv) and 6 weeks (bvdv) old. An additional 4 cdcd pigs fed a liquid diet without virus or antibody remained free of any appreciable serum reactivity for either bpv or bvdv. Results supported the hypothesis that antibodies for bpv previously detected in the serum of pigs and people may reflect ingestion of virus-contaminated bovine milk or milk products.
Immunoglobulin isotype of specific antibodies in reproductive tract secretions and sera in Tritrichomonas foetus-infected heifers
Authors: Skirrow Susan Z. , BonDurant R. H.
Published: January 2024

Four virgin heifers were experimentally inoculated intravaginally with 7 × 106 Tritrichomonas foetus, and 2 heifers served as uninfected controls. The durations of infection were 13, 20, 21, and 28 weeks, respectively. An ELISA that used whole T foetus antigen was used to detect anti-T foetus immunoglobulins (IgA, IgG1, IgG2, and IgM) in vaginal, cervical, and uterine secretions, and sera during the course of infection. The vaginal and cervical antibody responses were characterized by significantly increased T foetus-specific IgA and IgG1 at 7 to 9 weeks of infection, whereas uterine IgA and IgG1 responses peaked at 10 to 12 weeks. The antibody response in serum was predominantly of the IgG1 and IgG2 subclasses. In all reproductive tract regions, IgA persisted at least until the time of T foetus clearance, and usually longer. The next most persistent isotype was IgG1, lasting longest in the vagina, then cervix, and for the shortest time in the uterus. In local secretions, IgG2 was seen only transiently, increasing at weeks 13 to 15 in the vagina, and at weeks 10 to 12 in the cervix. Little IgM, relative to that present before infection, was detected in any secretion or serum, although cervical secretions had the greatest amount. Eight to 12 weeks after clearance, the 4 experimental heifers were inoculated intravaginally with 1 × 105 T foetus; transient infections (2 to 3 weeks' duration) were established in only 2 of 4 heifers, as determind by culturing of reproductive tract secretions. The lag times of antibody responses during this reinfection were shorter than in the initial infection, and elisa optical densities were at least as high as during the primary infection, suggesting an anamnestic response.
Effect of interferon or Propionibacterium acnes on the course of experimentally induced feline infectious peritonitis in specific-pathogen-free and random-source cats
Authors: Weiss Richard C. , Cox Nancy R. , Oostrom-Ram Theresia
Published: January 2024

Seventy-four cats (52 treated and 22 untreated) were evaluated in efficacy studies of interferon (ifn), Propionibacterium acnes, or a combination of these drugs against experimentally induced feline infectious peritonitis (fip). Cats were given doses of recombinant human leukocyte (α) ifn (rHuIFN-α), feline fibroblastic (β) ifn (FIFN-β) or P acnes at regular intervals before and after inoculation of virulent fip virus (fipv). Prophylactic and therapeutic administration of high doses (106 U/kg of body weight) or moderate doses (104 U/kg) of rHuIFN-α, FIFN-β (103 U/kg), or P acnes (0.4 or 4 mg) did not significantly reduce mortality in treated vs untreated cats. However, the mean survival time in cats treated with 106 U of rHuIFN-α-/kg alone or combined with doses of P acnes was significantly (P = 0.03) increased after inoculation of highly lethal amounts (200 LD100) of FIPV vs survival time in untreated cats. Although P acnes alone was ineffective, there was some indication that a combination of P acnes and high doses of rHuIFN-α was more effective than rHuIFN-α alone. Seemingly, the efficacy of rHuIFN-α treatment was improved in cats challenge-exposed with less fipv; in 1 trial, 4 of 5 cats (80%) treated with high doses of rHuIFN-α survived after inoculation of minimal lethal amounts (0.6 LD100) of fipv, whereas only 2 of 5 untreated cats (40%) survived.

Pretreatment of cats with 106 U of rHuIFN-α/kg resulted in detectable serum ifn activity 24 hours later; serum ifn activity was not detected in cats pretreated with P acnes, fifn-β, or 104 U of rHulFn-α/kg. After inoculation of fipv, increase in serum ifn activity and virus-neutralizing antibody (vna) titer was observed in treated or untreated cats, but increase in serum ifn activity or vna titer was not associated with protective immunity. In contrast to untreated cats, those treated with high doses of rHuIFN-α had temporary suppression of clinical signs of fip and decreased serum ifn or vna responses to fipv, suggesting some antiviral or immunomodulatory (or both) activities. Immunomodulation by rHuIFN-α in cats inoculated with fipv also was suggested by necropsy findings of increased paracortical hyperplasia and decreased necrosis in lymphoid tissues of ifn-treated vs untreated cats.

Results indicated that intensive treatment alone with ifn or P acnes failed to protect most cats against fatal disease after challenge exposure with lethal doses of fipv. High doses of rHuIFN-α alone or combined with P acnes, however, temporarily suppressed disease signs and extended survival time, suggesting a potential role of rHulFN-α as adjunctive, rather than primary, treatment for fip.
Morphometric and ultrastructural study of postnatal lung growth and development in calves
Authors: Castleman W. L. , Lay J. C.
Published: January 2024

The objectives of this study were to characterize basic patterns of postnatal lung growth in 1- to 150-day-old Holstein calves and to identify periods of accelerated lung growth and times of epithelial cell development that might correlate with periods of heightened susceptibility to pulmonary injury by infective agents and dietary toxins. Calves had fully developed alveoli at birth. There was an age-associated increase in total alveolar surface area and alveolar number, which was most marked in calves older than 30 days. Lung volume and body weight increases were also most marked when calves were older than 30 days. Mean bronchiolar cross-sectional area increased significantly (P < 0.05) with age, and there was a significant (P < 0.05) decrease in the percentage of terminal bronchioles with diameters < 3 × 104 μm between 1 and 150 days. In newborn calves, nonciliated bronchiolar epithelial cells retained fetal characteristics of differentiation, including abundant cytoplasmic glycogen and sparse agranular endoplasmic reticulum. Glycogen deposits were depleted, and agranular endoplasmic reticulum was developed in nonciliated cells by the time calves were 30 days old. We concluded that bronchiolar epithelium in calves is well differentiated by the time they are 30 days old and that lung growth in calves raised in semi-isolation begins most rapidly when calves are approximately 30 days old.
Role of complement S protein (vitronectin) in adherence of Streptococcus dysgalactiae to bovine epithelial cells
Authors: Filippsen Laerte F. , Valentin-Weigand Peter , Blobel Hans , Preissner Klaus T. , Chhatwal Gursharan S.
Published: January 2024

The binding of bovine complement S protein (vitronectin) to Streptococcus dysgalactiae isolates from cattle with mastitis and the S protein's role in streptococcal adherence to bovine epithelial cells were investigated. All 25 clinical isolates of S dysgalactiae interacted with bovine S protein. None of the other streptococcal species tested bound to bovine S protein. The S protein-binding sites were saturable and highly sensitive to trypsin. The binding of bovine S protein to S dysgalactiae isolates was specific and could not be inhibited by other plasma proteins, such as fibronectin, albumin, fibrinogen, α2-macroglobulin, or IgG. Similarly, streptococcal binding of bovine S protein was not influenced by the synthetic peptide Gly-Arg-Gly-Asp-Ser, which constituted the host cell attachment sequence of S protein. In adherence experiments, prior binding of bovine S protein to S dysgalactiae enhanced streptococcal adherence to bovine epithelial cells. The enhancing effects by bovine S protein were abolished when the respective binding sites on the streptococci were digested by trypsin. Thus, bovine S protein could be an important mediator of adherence of S dysgalactiae to bovine epithelial cells.
Evaluation of the efficacy and safety of two formulations of pyrantel pamoate in cats
Authors: Reinemeyer Craig R. , DeNovo Robert C.
Published: January 2024

The efficacy of paste and granule formulations of pyrantel pamoate against concurrent infections of Toxocara cati and Ancylostoma tubaeforme in cats was examined in a controlled trial. Three groups of 8 cats received either no medication (controls) or pyrantel pamoate in paste or granule formulations at a dosage of 20 mg/kg of body weight. After administration of the paste formulation, fecal egg counts of A tubaeforme and T cati were decreased by 98.6 and 96.4%, respectively, and 100% of hookworms and 93.5% of ascarids were removed from the intestine. After administration of the granule formulation, fecal egg counts of A tubaeforme and T cati were decreased by 99.4 and 78.2%, respectively, and 100% of adult hookworms and 88.9% of ascarids were removed. All reductions of egg counts and worm numbers were significant (P < 0.01).

The clinical safety of pyrantel pamoate was evaluated in 4- to 6-week-old kittens. Three groups of 10 kittens received either no medication (controls) or pyrantel pamoate in paste or granule formulations at the rate of 100 mg/kg for 3 consecutive days. Adverse effects were not observed in young kittens following administration of the high dose of pyrantel pamoate.
Acute airsacculitis in turkeys inoculated with phorbol myristate acetate
Authors: Ficken M. D. , Barnes H. J.
Published: January 2024

Phorbol myristate acetate (pma), which induces acute pulmonary injury in mammals, induced acute airsacculitis in turkeys after intra-airsac inoculation of 0.1 mg/kg. Grossly, air sacs contained multifocal to diffuse hemorrhage and edema at postinoculation hours (pih) 3 and 6. Microscopically, there was multifocal congestion and small thrombocyte aggregates within small blood vessels by pih 0.5, with a few vessels containing small numbers of marginating heterophils. By pih 1.5, thrombocyte aggregates were larger and more numerous, and moderate numbers of heterophils were located perivascularly. Erythrocytes and proteinaceous fluid were in air sac interstitium. By pih 3 and 6, hemorrhage and exudation of proteinaceous fluid had increased, in some instances severely distending the air sac. Ultrastructurally, changes resulting from pma-induced injury were thrombocyte aggregation and degeneration, air sac epithelial cell vacuolation with separation of interdigitating cell processes, and endothelial cell vacuolar degeneration with loss of vascular integrity. Air sac lavage fluids had mildly increased total cell counts by pih 1.5, but values returned to baseline by the end of the experiment, indicating lack of cell exudation into the air sac lumen. Circulating leukocyte changes included transient lymphopenia at pih 3 and marked heterophilia at pih 6. These results indicate that thrombocytes and/or heterophils are central to the pathogenesis of injury induced in air sacs by pma and that the air sac responds differently to pma than to pathogenic bacteria.
Bovine leukosis virus transmission with mouthparts from Tabanus abactor after interrupted feeding
Authors: Perino L. J. , Wright R. E. , Hoppe K. L. , Fulton R. W.
Published: January 2024

A successful attempt was made to mechanically transmit bovine leukosis virus (blv) from a blv-infected cow with a normal lymphocyte count to sheep by inoculation with horse fly (Tabanus abactor) mouthparts. After interrupted natural feeding, horse flies were anesthetized with CO2. Mouthparts were severed and pooled into a tissue grinder containing medium. Five inocula containing the mouthparts of 10 flies each, and 5 inocula containing the mouthparts of 20 flies each, were prepared and inoculated sc in the right axilla of 10 blv antibody-negative sheep. Five additional sheep served as controls. Serum samples were collected at 2-week intervals and tested by agar gel immunodiffusion for blv antibodies.

One sheep injected with 20 mouthparts developed antibodies to blv at 10 weeks after inoculation. Six months after inoculation with fly mouthparts, 1 blv antibody-negative sheep was randomly selected from each treatment group and injected, in the left axilla, with 3 ml of blood from the donor cow to confirm susceptibility of the sheep. All 3 sheep developed antibodies to blv within 4 weeks.
Cardiovascular effects of butorphanol in halothane-anesthetized dogs
Authors: Greene S. A. , Hartsfield S. M. , Tyner C. L.
Published: January 2024

Cardiovascular effects of butorphanol (0.2 mg/kg of body weight, iv) and responses associated with subsequent administration of naloxone (0.04 mg/kg, iv) were studied in halothane (1.2% end-tidal concentration)-anesthetized dogs. Transient, but statistically significant (P < 0.05), decreases in heart rate, mean and diastolic arterial blood pressures, and rate-pressure product were observed after butorphanol administration. Cardiac index, stroke volume, and systemic vascular resistance did not change significantly. Except for the decrease in heart rate, changes in the values of the cardiovascular variables measured after butorphanol administration did not appear to be clinically relevant. Sixty minutes after butorphanol administration, naloxone was given. Statistically significant (P < 0.05) increases in heart rate, arterial blood pressures, cardiac index, and rate-pressure product, along with dysrhythmias were observed. Stroke volume and systemic vascular resistance remained unchanged after administration of naloxone. Naloxone administration was associated with changes indicative of increased myocardial oxygen consumption.
Comparison of plasma, liver, and skeletal muscle carnitine concentrations in cats with idiopathic hepatic lipidosis and in healthy cats
Authors: Jacobs Gilbert , Cornelius Larry , Keene Bruce , Rakich Pauline , Shug Austin
Published: January 2024

Concentrations of total, free, and esterified carnitine were determined in plasma, liver, and skeletal muscle from cats with idiopathic hepatic lipidosis and compared with values from healthy cats. The mean concentrations of plasma, liver, and skeletal muscle total carnitine; plasma and skeletal muscle free carnitine; and plasma and liver esterified carnitine were greater (P < 0.05) in cats with idiopathic hepatic lipidosis than in control cats. The mean for the ratio of free/total carnitine in plasma and liver was lower (P < 0.05) in cats with idiopathic hepatic lipidosis than in control cats. These data suggest that carnitine deficiency does not contribute to the pathogenesis of feline idiopathic hepatic lipidosis.
Quantitative noninvasive assessment of liver size in clinically normal dogs
Authors: Godshalk Cynthia P. , Kneller Stephen K. , Badertscher Robert R. , Essex-Sorlie Diane
Published: January 2024

Measurements of liver size were made from radiographs of 16 clinically normal anesthetized dogs. Two measurements were made from each of 3 views: right and left lateral and ventrodorsal. Each measurement was correlated with liver weight and volume. Liver weight and volume were also correlated with both measurements from the same radiograph multiplied together. All measurements, with the exception of ventrodorsal depth, correlated significantly (P < 0.05) with liver weight and volume. The multiplication of the 2 measurements made from the right lateral radiograph correlated most highly with liver weight. These data were then compared with those from similar studies involving liver measurements obtained from nuclear scintigraphic and ultrasonographic scans on the same dogs. The radiographic measurements made from the right lateral view had the highest correlation with liver weight, followed by the nuclear scintigraphic measurements made from the same position.
Complement resistance in Actinobacillus (Haemophilus) pleuropneumoniae infection of swine
Authors: Rycroft A. N. , Cullen J. M.
Published: January 2024

The possible role of the complement-mediated bactericidal system in protection of swine against contagious pleuropneumonia was investigated. Strains of Actinobacillus (Haemophilus) pleuropneumoniae representing serotypes 2, 3 and 5 were found to be fully resistant to the bactericidal action of porcine serum from precolostral, clinically normal adult, and chronically infected pigs. All strains were also resistant to hyperimmune rabbit serum, but 3 of 4 strains were sensitive to normal human serum. This bactericidal effect was lost when human serum was previously absorbed with the homologous bacteria, indicating that antibody was necessary for killing. Addition of human serum to porcine serum or to absorbed human serum did not restore the bactericidal system. Pretreatment of the bacteria with undiluted heat-treated human serum also failed to sensitize the bacteria to the absorbed serum, indicating that a heat-labile, absorbable factor may have been required for killing of A pleuropneumoniae. None of the strains was sensitized to porcine serum by sublethal treatment with polymyxin B, a treatment that is known to disrupt the integrity of the outer membrane and induce serum sensitivity in gram-negative bacteria. The ability of A pleuropneumoniae to resist complement killing in vitro may reflect a virulence mechanism in vivo that assists bacteria in avoiding the pulmonary defenses of swine and promotes bacterial invasion of the lungs.
Ventricular arrhythmogenic dose of epinephrine in dogs and cats anesthetized with tiletamine/zolazepam and halothane
Authors: Bednarski Richard M. , Muir William W.
Published: January 2024

The ventricular arrhythmogenic dose of epinephrine (ade) was determined in 6 dogs anesthetized with halothane alone or with halothane after injection of tiletamine/zolazepam (tz). Respiratory rate and tidal volume were controlled and sodium bicarbonate was administered to maintain arterial pH and blood gas values within reference range. Heart rate and arterial blood pressure were recorded during determination of the ade. The ade (mean ± sd) was no different during anesthesia with use of halothane alone (8.9 ± 4.3) than it was when injections of tz preceded administration of halothane (6.7 ± 2.8). Tiletamine/zolazepam was also administered iv immediately after determination of the ade during halothane-induced anesthesia. The tz administered in this manner did not alter the ade. Blood pressure and heart rate were significantly greater during infusion of epinephrine than immediately prior to infusion. The administration of tz did not alter blood pressure response.

The ade was also determined in 6 cats anesthetized with halothane preceded by administration of tz. The ade (mean ± sd) was 0.7 ± 0.23 μg/kg, a value similar to that reported for cats during anesthesia with halothane alone.
Heritability of susceptibility to scrotal herniation in swine
Authors: Vogt D. W. , Ellersieck M. R.
Published: January 2024

Data on 5,711 Duroc-sired, 2,227 Landrace-sired, and 2,494 Yorkshire-sired male pigs born over a 9-year period were used to evaluate the genetic influence on scrotal herniation. Differences in frequency of this defect among boar breeds (Duroc, Landrace, and Yorkshire) were significant (P < 0.01). Differences among sires within the Duroc and Landrace boar groups were significant (P < 0.001 and P < 0.05, respectively), but differences within the Yorkshire group were not significant. Frequency of scrotal hernia among male full siblings of affected males was consistently higher than the overall frequency of the defect among progeny in each of their respective breed of boar groups. Percentage of affected pigs among male full siblings of affected males for Duroc, Landrace, and Yorkshire groups, respectively, was 3.0, 3.0, and 2.7 times greater than the overall percentage affected in their respective breed groups. Heritability of susceptibility to scrotal hernia development was estimated to be 0.29 ± 0.17, 0.34 ± 0.23, and 0.34 ± 0.19 in Duroc, Landrace, and Yorkshire-sired pig groups, respectively.
Procollagen type-III aminoterminal peptide in serum and synovial fluid of dogs with hip dysplasia and coxarthrosis
Authors: Madsen J. S. , Jensen L. T. , Strøm H. , Hørslev-Petersen K. , Svalastoga E.
Published: January 2024

Hip dysplasia is an affection of the coxofemoral joint that progresses until stabilization is caused by fibrosis and osteoarthritic changes. This stabilization process can be examined by clinical and radiographic methods. The capability of evaluating the procollagen concentrations in liquids, such as serum and synovial fluid, has further offered the basis for an objective biochemical evaluation of the stabilization process. Our study was performed to evaluate whether determination of procollagen concentrations was suitable for the use in practice.

The procollagen type-III aminoterminal peptide (p-III-np) concentration was measured in serum and in synovial fluid from coxofemoral joints in 20 dogs. Dogs were grouped on the basis of evidence of dysplasia and osteoarthritic changes of the hip: (1) a control group of 6 dogs without clinical or radiographic signs of hip dysplasia, and (2) dysplastic group of 14 dogs, which was further grouped with respect to the coxofemoral joint laxity, as determined by the Ortolani test.

Synovial fluid concentration of p-III-np was significantly (P < 0.05) higher in fluid from dysplastic joints than in fluid from normal joints. Serum concentrations of p-III-np were significantly (P < 0.05) higher in dogs in which results of the Ortolani test were positive.
Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after sedation with xylazine
Authors: Dooley M. P. , Pineda M. H. , Hopper J. G. , Hsu W. H.
Published: January 2024

Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after administration of xylazine was examined. In experiment 1, the mean (± SD) spermatozoal concentration in urine collected by cystocentesis before ejaculation was 0.322 ± 0.645 × 106/ml. After ejaculation, motile spermatozoa were present in the urine collected by cystocentesis from 12 of 15 dogs, and the concentration of spermatozoa in the urine (5.139 ± 7.014 × 106/ml) was higher (P < 0.025) than the concentration in the urine collected before ejaculation. The percentage of the total number of spermatozoa that were displaced during ejaculation and flowed into the urinary bladder (retrograde flow) ranged from 0 to 99.75% (24.67 ± 33.98%).

In experiments 2 and 3, administration of xylazine to sexually rested dogs induced retrograde flow of spermatozoa into the urinary bladder. In experiment 2, all dogs had spermatozoa in urine collected after xylazine administration, with motile spermatozoa present in the urine from 9 of 10 dogs. In experiment 3, urine collected from dogs before administration of xylazine was azoospermic or contained few, nonmotile spermatozoa (0.063 ± 0.135 × 106/ml), whereas urine collected after administration of xylazine had more (P < 0.025) and motile spermatozoa (3.717 ± 4.273 × 106/ml).

In experiment 4, administration of xylazine to dogs after ejaculation did not increase the concentration of spermatozoa in the urine. Results indicate that spermatozoa flow into the urinary bladder of dogs during ejaculation or after administration of xylazine to sexually rested dogs.
Endomyocardial biopsy in cats
Authors: Rush John E. , Keene Bruce W. , Eicker Steven W.
Published: January 2024

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in anesthetized healthy cats positioned in left lateral recumbency. At least 6 endomyocardial biopsy specimens were obtained from the right ventricle or interventricular septum of 11 cats. In 4 cats, the right jugular vein was torn during attempts to pass the introducing catheter into the right ventricle; however, in only 1 cat did this preclude catheter passage. This cat's heart was biopsied via the left jugular vein. Except for damage to the jugular vein, complications were infrequent, and the biopsy procedure was well tolerated by all cats.
Morphologic and ultrastructural evaluation of effect of ischemia and dimethyl sulfoxide on equine jejunum
Authors: Arden Warwick A. , Slocombe Ronald F. , Stick John A. , Parks Andrew H.
Published: January 2024

Morphologic changes in equine jejunal segments subjected to 1 hour of ischemia and 1 hour of reperfusion, and protective effects of systemic administration of dimethyl sulfoxide (dmso; 1 g/kg of body weight) were investigated in 18 ponies, using light microscopy and scanning and transmission electron microscopy. Ponies were allotted to 4 groups: group 1—control (n = 3); group 2—dmso (n = 3); group 3—ischemia (n = 6); and group 4—ischemia and dmso (n = 6). In each pony, 2 jejunal sections were evaluated. The first section was obtained prior to induction of ischemia, and the second was obtained 2 hours later after reperfusion. Mucosal lesions were graded from 0 (normal) to 5 (most severe).

Combined ischemia and reperfusion of 2 hours’ duration induced moderately severe mucosal injury to the equine jejunum (group 3; grade 1.5 to 2.5), characterized principally by disruption of enterocyte attachment from the basement membrane and lamina propria. Fluid accumulation disrupted enterocyte cell-to-cell adhesion toward cell bases, while apical tight junctions and desmosomal junctions toward the luminal surface remained intact. Intracytoplasmic organellar changes within enterocytes were not a prominent feature of the injury. The aforementioned processes were marked at the villus tip and progressed down the villus sides. These findings support the importance of mechanisms leading to early sub-epithelial fluid accumulation rather than that of direct severe enterocyte injury. Further, fluid accumulation does not appear to arise from intercellular migration from the luminal surface. In this model, a pathomechanical effect caused by vigorous villus retraction appears to exacerbate epithelial lifting toward the villus tip. Systemic administration of dmso (1 g/kg) prior to reperfusion failed to improve the appearance of the mucosa (group 4; grade 1.5 to 4.0), suggesting that it was ineffective in preventing this form of ischemia-reperfusion injury.
Lectin histochemical characteristics of the canine female mammary gland
Authors: Castagnaro Massimo , Canese Maria G.
Published: January 2024

Twelve biotinylated lectins and an avidin-biotin-peroxidase method were used to detect and localize specific carbohydrate residues on formalin-fixed, paraffin-embedded female canine mammary gland sections. Histologic sections from 3 lactating and 7 nonlactating mixed-breed dogs (age 5.6 ± 0.35 years) were incubated with Arachis hypogea agglutinin (peanut agglutunin; pna), Concanavalia ensiformis agglutinin (conA), Dolichos biflorus agglutinin (dba), Glycine max agglutinin (sba), Griffonia simplicifolia agglutinin-I (gs-I), Lens culinaris agglutinin (lca), Lycopersicon esculentum agglutinin (lea), Phytolacca americana mitogen (pokeweed mitogen; pwm), Ricinus communis agglutinin-I and-II (rca-I and -II), Triticum vulgaris (wga), and Ulex europaeus agglutinin-I (uea-I). Each lectin had a specific binding pattern, except sba and dba.

In nonlactating glands, pna, conA, lea, and uea-I stained duct cells in a linear-binding pattern, with a mean percentage of positive ducts per section of 28.7 (± 0.6), 65.7 (± 0.3), 100 (± 0), and 8.4 (± 0.2), respectively. Strong apical, lateral, basal, and cytoplasmic positivity on duct cells was seen after incubation of the sections with rca-I, rca-II, and wga in all ducts. In acinar cells, the binding pattern and the staining distribution of all the lectins studied were similar to those in duct cells. However, for pna, conA, and uea-I, the mean percentage of positive lobules per section was 33.7 (± 0.9), 62 (± 0.5), and 10.5 (± 0.2), respectively.

In glands from lactating dogs, conA and uea-I did not stain. The cytoplasm of all myoepithelial cells was moderately stained with rca-I, rca-II, and wga. Endothelial cells stained with gs-I, pwm, rca-I, rca-II, wga, conA, and lca. The extracellular matrix, especially the periacinar and periduct regions, and the interstitial fibroblasts were positive for lca, rca-I, rca-II, and wga. Peripheral unmyelinated nerve fibers of the nipple were strongly positive for GS-I, pwm, rca-I, rca-II, and wga. Some of the lectins used (ie, pna, conA, uea-I, gs-I, pwm, and lea) appear to have selective staining of mammary gland structures that seems to be correlated with various physiologic functions. The contrasting binding pattern of lectins specific for the same sugar indicates a lack of knowledge of interactions between lectins and carbohydrate residues in tissue sections.
Evaluation of the Schirmer tear test in clinically normal rabbits
Authors: Abrams Kenneth L. , Brooks Dennis E. , Funk Richard S. , Theran Peter
Published: January 2024

Mean (± SD) value for results of the Schirmer tear test without use of topical anesthesia on 142 rabbit eyes was 5.30 (± 2.96) mm/min; range was 15 mm/min, with low value of 0 and high value of 15 mm/min. Two SD from the mean provided a normal clinical range of 0 to 11.2 mm/min for inclusion of 95% of the population. Significant differences were not evident between eye (right vs left) or gender or among breeds; interaction among eye, gender, and breed also was not observed. Although mean values for 2 breeds were significantly different from values in the other 10 breeds and from each other, they were still within the proposed normal range of 2 SD. The Schirmer tear test without topical anesthesia may be useful in rabbits for evaluation of increased values correlated with ocular irritation, rather than for determination of decreased values associated with keratoconjunctivitis sicca.
Hemodynamic effects of carbon dioxide during intermittent positive-pressure ventilation in horses
Authors: Wagner Ann E. , Bednarski Richard M. , Muir William W.
Published: January 2024

The hemodynamic effects of high arterial carbon dioxide pressure (PaCO2) during anesthesia in horses were studied. Eight horses were anesthetized with xylazine, guaifenesin, and thiamylal, and were maintained with halothane in oxygen (end-tidal halothane concentration = 1.15%). Baseline data were collected while the horses were breathing spontaneously; then the horses were subjected to intermittent positive-pressure ventilation, and data were collected during normocapnia (PaCO2, 35 to 45 mm of Hg), moderate hypercapnia (PaCO2, 60 to 70 mm of Hg), and severe hypercapnia (PaCO2, 75 to 85 mm of Hg). Hypercapnia was induced by adding carbon dioxide to the inspired gas mixture. Moderate and severe hypercapnia were associated with significant (P < 0.05) increases in aortic blood pressure, left ventricular systolic pressure, cardiac output, stroke volume, maximal rate of increase and decrease in left ventricular pressure (positive and negative dP/dtmax, respectively), and median arterial blood flow, and decreased time constant for ventricular relaxation. These hemodynamic changes were accompanied by increased plasma epinephrine and norepinephrine concentrations. Administration of the β-blocking drug, propranolol hydrochloride, markedly depressed the response to hypercapnia. This study confirmed that in horses, hypercapnia is associated with augmentation of cardiovascular function.
Evaluation of equine digital Starling forces and hemodynamics during early laminitis
Authors: Allen Douglas , Clark E. Susan , Moore James N. , Prasse Keith W.
Published: January 2024

A carbohydrate overload model was used in 8 horses to evaluate Starling forces and hemodynamics of the digit during the prodromal stage of acute laminitis. A pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, capillary pressure, isogravimetric capillary filtration coefficient, osmotic reflection coefficient, and vascular compliance.

From these data, pre- and postcapillary resistances and pre- to postcapillary resistance ratios were determined. Vascular and tissue oncotic pressures were estimated from plasma and lymph protein concentrations, respectively. The osmotic reflection coefficient, an estimation of capillary permeability, was determined by means of the lymph protein wash-down technique. Using the collected data, tissue pressure in the digit was calculated by use of the Starling equation.

In the isolated digit, mean isogravimetric capillary pressure was 55.13 mm of Hg, mean plasma and lymph oncotic pressures were 22.29 mm of Hg and 7.2 mm of Hg, respectively, the mean osmotic reflection coefficient was 0.66, the mean capillary filtration coefficient was 0.003 ml/min/mm of Hg/100 g, and mean interstitial fluid pressure was 44.82 mm of Hg. The high capillary pressure appeared to be caused by high vascular resistance from the venous side, predisposing to enhanced capillary filtration and interstitial fluid accumulation.
Effects of a histamine type-2 receptor antagonist (BMY-25368) on gastric secretion in horses
Authors: Orsini James A. , Dreyfuss Daniel J. , Vecchione Josephine , Spencer Pamela A. , Uhlman Richard
Published: January 2024

The effects of a potent new histamine-2 (H2) receptor antagonist, BMY-25368, were studied on gastric acid secretion in 5 foals from which food was withheld. Doses of 0.02, 0.11, 0.22, and 1.10 mg/kg of body weight were administered im in a randomly assigned treatment sequence. Following BMY-25368 administration, hydrogen ion concentration was decreased and mean pH was higher than baseline values in a dose-response pattern. At the 0.22 and 1.10 mg/kg doses, the high pH was sustained for > 4 hours. The BMY-25368 thus may be useful for treating gastric ulcer disease in horses.