bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nonadrenal illness on adrenal function in the cat
Authors: Zerbe C. A. , Refsal K. R. , Peterson M. E. , Armstrong P. J. , Nachreiner R. F. , Schall W. D.
Published: February 2025

Adrenal function was assessed by a combined dexamethasone suppression-ACTH stimulation test in 18 healthy cats, 17 diabetic cats, and 19 sick nondiabetic cats. In all groups, plasma Cortisol concentrations decreased after dexamethasone was administered and increased after ACTH was administered. There were no significant (P > 0.05) differences among groups in time trend changes in Cortisol concentration. There was considerable variation in adrenal response between cats in each group. Diabetic cats had more variation in base-line and postdexamethasone plasma Cortisol concentrations (P < 0.05) than did other groups. In sick, nondiabetic cats, Cortisol concentrations tended to be higher in cats with hyperthyroidism (P = 0.06) than in cats with other diseases.
Isoprinosine and levamisole immunomodulation in artificially reared neonatal pigs
Authors: Hennessy K. J. , Blecha F. , Pollmann D. S. , Kluber E. F.
Published: February 2025

An experiment was conducted to determine the capability of isoprinosine (iso) and levamisole (lev) to augment delayed-type hypersensitivity and lymphocyte blastogenic reactions in artificially reared pigs. Sow-reared pigs (n = 15) were kept with their dams; artificially reared pigs (n = 15) were removed from sows within 2 days after parturition and reared artificially for 21 days. Isoprinosine was administered orally (75 mg/kg/day) from days 0 to 10. Levamisole (2 mg) was injected subcutaneously on days 5 and 10. Control pigs were given distilled water orally from days 0 to 10 and injected subcutaneously with 0.15M NaCl on days 5 and 10. Lymphocyte proliferative responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen were evaluated at week 2. The phytohemagglutinin skin-test responses were evaluated in all pigs at weeks 1 and 3 of the trial. Hematologic values, body weight, and mortality were evaluated each week.

The skin-test responses and mitogen-induced lymphocyte proliferative responses were lower (P < 0.05) in artificially reared controls when compared with responses in sow-reared pigs. However, iso and lev enhanced (P < 0.05) the responses in the artificially reared pigs to values comparable with those of the sow-reared controls. Body weight was greater (P < 0.01) in sow-reared pigs than in artificially reared pigs; drug treatment did not influence weight gain. These data indicate that immunopotentiation of the cellular immune responsiveness of artificially reared pigs may be possible with iso or lev.
Virulence of wild and mutant strains of Salmonella typhimurium in ligated intestinal segments of calves, pigs, and rabbits
Authors: Clarke R. C. , Gyles C. L.
Published: February 2025

A ligated intestine model in calves, pigs, and rabbits was tested for its value as an indicator of virulence of potential vaccine strains of Salmonella typhimurium. A wild virulent strain (3860C), a laboratory strain LT2, and mutants of these 2 strains were evaluated. Inoculation of calf intestinal segments with strain 3860C revealed that fluid responses were greatest in the proximal portion of the small intestine and that doses > 107 organisms were required to produce fluid responses and mucosal damage. Immunoperoxidase-stained sections of intestine revealed that a large dose of Salmonella organisms was required before mucosal invasion could be detected. Aromatic (aroA), galactose epimerase (galE), and diaminopimelic acid (dap) mutants of strain 3860C all resulted in much less fluid response, mucosal invasion, and mucosal damage compared with those by the parent organism. Strain LT2 induced such weak responses that it was not possible to evaluate reductions in virulence of its mutants. In 6-week-old pigs, there was no fluid response to any strains; however, in 1-week-old pigs, there was fluid response to the wild strain and some of its mutants. In adult rabbits, fluid responses were not observed, except when the wild strain was inoculated in the proximal portion of the small intestine. The calf and 1-week-old pig models appeared to be best suited for assessment of virulence of mutant strains of S typhimurium.
Effect of acepromazine, diazepam, fentanyl-droperidol, and oxymorphone on gastroesophageal sphincter pressure in healthy dogs
Authors: Hall J. A. , Magne M. L. , Twedt D. C.
Published: February 2025

Treatment of healthy dogs with 4 commonly used psychotropic or analgesic agents significantly decreased resting gastroesophageal sphincter pressure (gesp). Acepromazine decreased gesp by 35% (P = 0.02); oxymorphone decreased gesp by 38% (P < 0.005); diazepam decreased gesp by 42% (P = 0.005); and fentanyl-droperidol decreased gesp by 40% (P = 0.03). Therefore, esophageal manometric evaluation of gastroesophageal sphincter function should not be preceded by administration of these drugs.
Opsonins of Streptococcus in uterine flushings of mares susceptible and resistant to endometritis: Control of secretion and partial characterization
Authors: Hansen Peter J. , Asbury Atwood C.
Published: February 2025

The release of opsonins into the uterine lumen of mares susceptible or resistant to endometritis was examined after intrauterine inoculation of a filtrate of Streptococcus culture fluid or vehicle. Uterine flushings were collected at 0.5 hour before and 2, 4, 6, 8, and 24 hours after inoculation on day 2 or 3 of estrus and on day 7 or 8 after ovulation. Amounts of opsonins in flushings were quantified as the H2O2 produced by leukocytes incubated with flushings-opsonized bacteria, compared with H2O2 produced by leukocytes incubated with nonopsonized bacteria. Opsonin values in flushings increased (P < 0.025) in all mares after inoculation of filtrate or vehicle. For mares resistant to endometritis, opsonin values were greater at diestrus than at estrus. The opposite was true for mares susceptible to endometritis, resulting in a status (susceptible vs resistant) × stage of cycle interaction (P < 0.025). Overall, opsonins were higher (P < 0.05) in flushings of mares susceptible to endometritis than in flushings of mares resistant to endometritis, but this difference was only apparent at estrus. Preliminary characterization of opsonins in uterine secretions by ammonium sulfate fractionation and gel filtration indicated that opsonins were mainly associated with an ammonium sulfate-soluble fraction of high molecular weight (> 4 × 106) and an ammonium sulfate-precipitable fraction that was associated with immunoglobulin G.
Plasma amino acid analysis in dogs with experimentally induced hepatocellular and obstructive jaundice
Authors: Rutgers Carolien , Stradley Roger P. , Rogers William A.
Published: February 2025

Plasma amino acid concentrations were determined weekly for 4 weeks in 6 sham-operated control dogs, in 6 sham-operated dogs after induction of liver disease with dimethylnitrosamine (dmna), and in 6 dogs after surgical ligation of the common bile duct. Results were compared with standard biochemical indices of liver function and with histologic changes in serial liver biopsy specimens. Concentrations of most amino acids increased after 2 weeks in dmna-treated dogs, whereas they were normal or decreased in bile duct-ligated dogs. With increasing severity of the liver disease, the molar ratio (normal mean ± sem = 3.48 ± 0.14) in dmna-treated dogs decreased to 2.42 ± 0.19 by 2 weeks and to 1.17 ± 0.09 by 4 weeks. The ratio remained normal in bile duct-ligated dogs. Molar ratio and aromatic amino acid concentrations correlated better with hepatic necrosis and inflammation than did standard biochemical indices (eg, bilirubin, liver enzymes). Therefore, plasma amino acid analysis and determination of the molar ratio may be useful in the differential diagnosis of hepatocellular and obstructive jaundice in dogs. A decrease in the molar ratio may reflect portal hypertension and hepatocellular disease.
Efficacies of trimethoprim-sulfadiazine and gentamicin sulfate in the treatment of fibrinous peritonitis in rats
Authors: Emms Stephen G. , Benson Charles E.
Published: February 2025

Trimethoprim-sulfadiazine and gentamicin sulfate decreased early mortality in an established model of fibrinous peritonitis in the rat. Both drugs failed to prevent abscess formation, indicating that there was poor penetration of fibrin; however, they significantly decreased (P < 0.01) bacterial numbers in residual abcesses. The colony count per abscess in the gentamicin sulfate-treated group was significantly lower (P < 0.01) than that in the trimethoprim-sulfadiazine-treated group.
Comparison of four serotests for the detection of Dirofilaria immitis infection in dogs
Authors: Thilsted John P. , Whorton Jerry , Hibbs Clair M. , Jillson Gregory P. , Steece Rick , Stromei Mary
Published: February 2025

Three hundred two dogs were tested with 4 serotests for heartworm antigen (ag) or antibody (ab) and with the Knott test. The 4 serotests evaluated were an enzyme-linked immunosorbent assay (elisa) for adult heart-worm-specific ab (ab-elisa), a quantitative, indirect immunofluorescent assay (ifa) for adult heartworm-specific ab (ab-ifa), an ifa test for microfilaria (mf)-specific ab (mf-ifa), and an elisa for adult heartworm ag (ag-elisa).

The presence of heartworms was ascertained in all dogs by necropsy examination. Of 302 dogs, 20 (6.6%) had heartworms in the heart at necropsy. Of infected dogs, 9 (45%) had occult infections.

Test sensitivities were 75%, 95%, 70%, and 75% for the ab-elisa, ab-ifa, mf-ifa, and ag-elisa, respectively. Test specificities were 85% (ab-elisa), 77% (ab-ifa), 87% (mf-ifa), and 99% (ag-elisa). The best agreement between serotest results and necropsy findings was obtained with the ag-elisa (97%). The 4 serotests detected 86% (ab-elisa), 100% (ab-ifa), 67% (mf-ifa), and 78% (ag-elisa) of the dogs with occult heartworm infection. A significant (P < 0.05) association between intestinal parasitism and positive heartworm test results was found with only ab-ifa.

Seemingly, the Knott test, or some other concentration method for detecting circulating mf should be the first heartworm test performed. If the examination for mf is negative, the dog has clinical signs, and radiographic findings are suggestive of occult heartworm infection, then a serotest for adult heartworm ag is recommended.
Scanning electron microscope study of platelet release by canine megakaryocytes in vitro
Authors: Handagama P. J. , Jain N. C. , Feldman B. F. , Kono C. S.
Published: February 2025

Megakaryocytes were isolated from bone marrow from healthy dogs, using a combination of density-gradient centrifiigation and polysucrose-velocity sedimentation techniques. The 2-step separation technique resulted in a preparation comprising 30% to 35% megakaryocytes of total nucleated cells. Accessibility to large numbers of viable canine megakaryocytes allowed investigation of platelet release by these cells in short-term cultures. Megakaryocytes were observed to form long cytoplasmic processes that gradually developed segmental constrictions and subsequently fragmented into platelet-sized pieces. Some platelet-sized cytoplasmic pieces of megakaryocytes presumably underwent discoid transformation.
Force plate analysis of the walking gait in healthy dogs
Authors: Budsberg Steven C. , Verstraete Mary C. , Soutas-Little Robert W.
Published: February 2025

Ground reaction forces, impulses, and their relationships to morphometric measurements were evaluated for walking gait in 17 healthy dogs. A force plate was used to record forces at 1-ms intervals. Vertical, craniocaudal, and mediolateral forces were measured and normalized by body weight. Impulses, defined as the total force applied over time, were calculated in vertical and craniocaudal directions. Craniocaudal impulses were further divided into braking and propulsion phases. Braking impulses were significantly greater in the forelimbs (P ≤ 0.001), whereas propulsion impulses were generally greater in the hind limbs. Impulses and peak forces were then compared with morphometric measurements (body weight, humeral and femoral lengths, and paw length). All relationships were linear, with correlation coefficients significant (P ≤ 0.001). As the size of the dog increased, braking, propulsion and vertical impulses increased. Conversely, as morphometric measurements increased, peak vertical forces decreased. Thus, larger dogs had a lower peak force on each limb, but had a higher total impulse applied during stance phase. As stance phase time increased, peak vertical forces decreased. The results indicated that healthy dogs had significant correlations between ground reaction forces, impulses, and morphometric measurements.
Surgical procedure for chronic biliary sample collection in pigs
Authors: Thurmon J. C. , Nelson D. R. , Bevill R. F. , Harrington G. W. , Magee D. N.
Published: February 2025

To collect biliary samples from pigs, catheters were placed in the distal end of the gallbladders in twelve 20-to 30-kg pigs. An occluder cuff was placed around the bile duct proximal to the duodenum. Inflation of the occluder cuff prevented bile flow into the duodenum and allowed total collection of bile from the catheter in the gallbladder. Deflation of the occluder cuff allowed return of bile flow into the duodenum. Two pigs developed gastric ulcers and two pigs had bile duct dilatation. These responses were attributed to occluder cuffs of inadequate size which could have caused partial or complete obstruction of the bile duct.
Atrial cannulation for long-term sequential blood collection in gilts
Authors: Kemp Charles , Kruger Jan S. J.
Published: February 2025

Polyvinyl chloride tubing (id, 1.27 mm; od, 2.29 mm) was placed via the jugular vein into the right atrium of thirty-five 120- to 200-day-old gilts. Catheters remained patent for 14 to 88 days (mean, 41 days). The major cause of loss of function was damage inflicted by the gilt (20 catheters), whereas only 3 catheters lost patency because of blockage. Using a pulley and counterweight system the exteriorized end of the catheter was suspended above the gilt, facilitating blood collection and minimizing disturbance of the gilts.
T-2 toxin-enhanced resistance against listeriosis in mice: Importance of gastrointestinal lesions
Authors: Ziprin Richard L. , Corner Donald E. , Ziegler H. Kirk
Published: February 2025

The role of T-2 toxin-induced gastrointestinal lesions in T-2 toxin-enhanced resistance to listeriosis in mice was evaluated. The T-2 toxin-induced lesions did not cause a starvation effect sufficient to enhance resistance to listeriosis. Administration of polymyxin E markedly reduced the gram-negative intestinal microflora and did not eliminate the toxin-induced resistance to listeriosis. The T-2 toxin did not cause an increased expression of Ia surface antigens on peritoneal macrophages. Thus, toxin-induced anorexia and starvation or absorption of grain-negative intestinal bacteria and endotoxins through toxin-induced gastrointestinal lesions did not account for the enhancing effect of T-2 toxin on resistance to Listeria monocytogenes infection in mice.
Equine endotoxemia: Cardiovascular, eicosanoid, hematologic, blood chemical, and plasma enzyme alterations
Authors: Ward D. S. , Fessier J. F. , Bottoms G. D. , Turek J.
Published: February 2025

Ponies with electromagnetic blood flow transducers implanted around the main pulmonary and left main coronary arteries, were used to evaluate effects of chronic sublethal endotoxin on cardiac output (co), stroke volume, and left coronary blood flow (lcbf). Plasma thromboxane (tx), as indicated by txb2, prostacyclin as indicated by 6-keto-prostaglandin (pg) F1α, and hematologic and blood chemical values also were evaluated. Over 24 hours, 2 groups of ponies were given progressively increasing iv and intraperitoneal doses of Escherichia coli lipopolysac-charide (lps) at 0, 6, 12, and 18 hours. Group 1 was not treated and group 2 was treated with flunixin meglumine, before each lps insult. Initial lps inoculation in group 1 led to 10-fold increases in txb2 and 6-keto-pgf1α values by 30 and 90 minutes, respectively. These eicosanoid values returned to base line by 6 hours after each insult.

Although repeated lps injections stimulated recurring high plasma concentrations of 6-keto-pgf1α, txb2 production became less with each successive lps insult. Cardiac output decreased to 55% to 60% of base-line values in association with increased 6-keto-pgf1α values. Left coronary blood flow could not be evaluated accurately. Severe lactic acidosis developed in group 1. Group-2 ponies remained clinically normal, indicating protection of cardiovascular function and peripheral perfusion with flunixin meglumine. Seemingly, flunixin meglumine helped to maintain acceptable cardiovascular function and tissue perfusion during endotoxemia. Flunixin meglumine given to healthy ponies had no effect on cardiovascular function. The fact that txb2 generation became minimal over time in the face of progressive deterioration of co, stroke volume, and lactic acidosis indicated that tx may not be involved in the pathogenesis of altered cardiovascular function and lactic acidosis occurring late in endotoxin-induced shock. Both groups had recurring leukopenia by 90 minutes after each lps insult. Although total wbc counts returned to base-line values by 6 hours after each insult in group 1, the count remained significantly (P < 0.05) below base line until 24 hours in group 2. The primary reason for the leukopenia in both groups was a neutropenia. Neutrophils appeared to remain sequestered in ponies given flunixin meglumine.
Thermodilution cardiac output determination in the guinea pig
Authors: Hart Mark V. , Mendelson David , Hosenpud Jeffrey D.
Published: February 2025

Thermodilution cardiac output was compared with simultaneously determined aortic flow in 5 guinea pigs during thoracotomy. Total cardiac output was affected by volume expansion, adrenergic stimulation, and the volume of hemorrhage. For the equation y = mx, where y is aortic flow, x is thermodilution cardiac output, and m is the slope of the regression line, m = 0.88 ± 0.02 (95% confidence interval). The se of the regression was 27.8 ml/min. Thermodilution may have been overestimated because the aortic flow measurement did not take into account the coronary arterial blood flow, which is approximately 4% of total cardiac output in the guinea pig. Indicator loss (ie, temperature) also may be an important factor in the calculation of cardiac output, as determinations of thermodilution cardiac output were affected by sampling site in the guinea pig. Thermodilution appears to be a useful and reliable means of determining cardiac output in the guinea pig.
Protection of lambs with a purified metabolite of exsheathed third-stage Haemonchus contortus larvae
Authors: Boisvenue R. J. , Galloway R. B. , Hendrix J. C.
Published: February 2025

Helminth-free lambs (approx 4 months old) were inoculated sc with a purified metabolite of exsheathed third-stage Haemonchus contortus larvae. The metabolite was obtained from in vitro cultivation and was identified as XL3FA1. After 3 periodic XL3FA1 inoculations, lambs were challenge exposed with H contortus. Multiple vaccinations with XL3FA1 did not inhibit the development of worm populations in the lambs; however, worm egg production seemed to be inhibited.
Electromyographic evaluation of adult Labrador Retrievers with type-II muscle fiber deficiency
Authors: Moore M. P. , Reed S. M. , Hegreberg G. A. , Kramer J. W. , Alexander J. E. , Meyer K. M. , Bryan G. M.
Published: February 2025

Labrador Retrievers with type-II muscle fiber deficiency were examined electrodiagnostically. Electromyographic changes consisted of positive sharp waves, fibrillation potentials, bizarre high-frequency discharges, and, rarely, myotonic-like discharges. Fasciculation potentials were recorded infrequently. Fibrillation potentials and bizarre high-frequency discharges were the most commonly observed electromyographic changes. Bizarre high-frequency discharges were prominent in muscles of the head and neck, proximal muscles of the thoracic limbs, and the thoracolumbar paraspinal musculature. Marked abnormalities were not observed in the motor nerve conduction velocity. Decrementai responses of the evoked compound muscle action potential to repetitive nerve stimulation were not observed.
Morphologic study of inclusions in tissues from pigs inoculated with cytomegalovirus
Authors: Narita Minoru , Kawamura Hitoshi , Shirai Junsuke , Haritani Makoto
Published: February 2025

Six 5-day-old gnotobiotic pigs inoculated intranasally with the J-1 strain of porcine cytomegalovirus (pcmv) were euthanatized within 9 to 18 days after inoculation. All pigs developed a subclinical form of pcmv infection and had characteristic intranuclear inclusions in all tissues.

Morphologically, 2 types of inclusions were observed. One was a small herpetic intranuclear inclusion in reticuloendothelial cells, which contained a few nucleocapsids in the nucleus. The other was a typical cytomegalic intranuclear inclusion in macrophages in the lungs and in tubuloalveolar gland cells in the nasal mucosa. Inclusions contained many nucleocapsids in the nucleus and a large number of enveloped viral particles in the cytoplasm. The distribution of the specific immunofluorescent antigen of pcmv was coincident with the presence of herpetic and cytomegalic inclusions.
Frequency of association of noncytopathic bovine viral diarrhea virus with mononuclear leukocytes from persistently infected cattle
Authors: Bolin Steven R. , Sacks Jerome M. , Crowder Stephen V.
Published: February 2025

All mononuclear leukocytes and T lymphocyte-enriched and B lymphocyte-enriched subpopulations of mononuclear leukocytes collected from 8 cows persistently infected with 1 of 3 isolates of noncytopathic bovine viral diarrhea virus were tested for association with virus. For all persistently infected cows, approximately 4.4% of all mononuclear leukocytes, 5.4% of T lymphocyte-enriched, and 2.1% of B lymphocyte-enriched subpopulations of mononuclear leukocytes were associated with virus. Differences between leukocyte populations in percentages of leukocytes associated with virus were real (P < 0.05). Among virus isolates, significant differences in percentages of leukocytes associated with virus were not detected.
Molecular specificity of the antibody responses of cattle naturally and experimentally infected with cytopathic and noncytopathic bovine viral diarrhea virus biotypes
Authors: Donis Rubén O. , Dubovi Edward J.
Published: February 2025

The specificity of the humoral IgG response of cattle naturally or experimentally infected with bovine viral diarrhea virus (bvdv) was studied by radioimmunopre-cipitation. Serum samples were tested against radiolabeled lysates of cells infected with cytopathic and noncytopathic biotypes of bvdv. A biotype-specific serologic marker was not detected. The specificity of the IgG induced in cows naturally or experimentally infected with either bvdv biotype was essentially the same. A strong IgG response to the 2 glycoproteins (56 to 58 kilodaltons, [kD] and 48 kD) of both biotypes and to the major polypeptides was induced in infected cells: 118 kD and 80 kD by cytopathic bvdv and only 118 kD by noncytopathic bvdv. The most consistent difference among cattle was the presence of IgG specific for the 37-kD polypeptide. Sequential serum sample collection after spontaneous and induced infections with either bvdv biotype did not indicate specific IgG markers for determining infection history. Sera from cattle with a confirmed diagnosis of mucosal disease and lacking neutralizing antibodies to bvdv usually lacked ( > 80%) nonneutralizing bvdv-specific IgG. One animal had substantial amounts of IgG to the 80-kD polypeptide. Other cattle had less readily detectable amounts of IgG specific for 80-kD or 37-kD viral polypeptides.
Tissue concentrations and pharmacokinetics of florfenicol in male veal calves given repeated doses
Authors: Adams P. E. , Varma K. J. , Powers T. E. , Lamendola J. F.
Published: February 2025

The pharmacokinetic disposition of florfenicol was studied in male veal calves given 11 mg of florfenicol/kg of body weight, iv and 11 mg of florfenicol/kg po every 12 hours for 7 doses. After florfenicol administration iv, the median elimination half-life was 222.8 minutes, whereas the median half-life of the distribution phase was 7.94 minutes. Median body clearance and apparent volume of distribution were 2.87 ml/kg/min and 0.907 L/kg, respectively.

After florfenicol administration, po, there was a wide variation in the calculated half-life, which was attributed to variation in the rate of florfenicol absorption. The half-life was 167.4 to 534.9 minutes after the first oral dose and 190 to 808.8 minutes after the seventh dose. The median bioavailability after the first oral dose was 0.8888. Peak and trough concentrations of florfenicol were increased after subsequent doses were administered, compared with those after the first oral dose. The percentage of protein binding in serum from one adult cow was 22% to 26%.

Florfenicol concentrations in tissues and body fluids of male veal calves were studied after the seventh dose of 11 mg of florfenicol/kg. High concentrations of florfenicol were measured in the urine, kidney, and bile. Low concentrations were measured in the brain, CSF, and aqueous humor. Concentrations in all other tissues and fluids studied were similar to the concurrent serum concentration.
Clinical, hematologic, and humoral immune response in female dogs inoculated with Rickettsia rickettsii and Rickettsia montana
Authors: Breitschwerdt Edward B. , Walker David H. , Levy Michael G. , Burgdorfer Willy , Corbett Wayne T. , Hurlbert Sue Ann , Stebbins Martha E. , Curtis Barbara C. , Allen Daniel A.
Published: February 2025

Female Beagles were inoculated intradermally with a sublethal dose of Rickettsia rickettsii and R montana. Three dogs (group 1) were inoculated with 2 × 102 plaque-forming units (pfu) of R rickettsia and were treated with tetracycline beginning on postinoculation day (pid) 12; 3 dogs (group 2) were inoculated with 2 × 102 pfu of R rickettsii but were not treated; 3 dogs (group 3) were inoculated with 2 × 102 pfu of R montana. Group-3 dogs failed to seroconvert and were inoculated a second time on pid 68.

Groups 1 and 2 dogs inoculated with R rickettsii became depressed and developed occasional inappetence, fever, hematochezia, and ocular lesions. These dogs had a decrease in pcv and rbc count, an initial decrease in wbc count followed by leukocytosis, and a decrease in platelet count. Group-3 dogs inoculated with R montana remained healthy.

After R rickettsii inoculation, the serologic response to spotted fever group (sfg) rickettsial antigens (R rickettsii, R rhipicephali, R montana, and R bellii) was similar. The antibody response to R rickettsii was first detected on pid 9, with peak titers reached by pid 20. Serum titers to R rickettsii remained stable or decreased one dilution through pid 120. Of 4 sfg rickettsial antigens, the highest serologic response was to R rickettsii. A cross-reacting antibody response with R rhipicephali and R montana was nearly identical and was only slightly less than the response to R rickettsii. Cross-reacting antibodies to R belli were of lower mean titer and of shorter duration than were cross-reacting antibodies to other sfg rickettsiae. A second inoculation with R montana resulted in antibody titers to all 4 sfg antigens, with the highest mean antibody titer to R montana.

All 9 dogs were challenge exposed with 2 × 102 pfu of R rickettsii on pid 216. Groups 1 and 2 dogs had mild depression, fever, and ocular lesions. Challenge exposure of group-3 dogs previously inoculated with R montana resulted in a similar pattern of clinical abnormalities and hematologic alterations, as was observed in groups 1 and 2 dogs inoculated initially with R rickettsii. The mean titers to all 4 sfg antigens were greater in dogs inoculated with R montana, than were responses to these antigens after inoculation with R rickettsii only. Despite antigenic similarity in canine immune recognition to R rickettsii and R montana, the use of nonpathogenic R montana to infer protection against R rickettsii was not successful.
Natural infection with Eimeria leuckarti: Prevalence of oocysts in feces of horse foals on several farms in Kentucky during 1986
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C.
Published: February 2025

During 1986, fecal specimens were collected 1 or more times from each of 164 horse foals (158 Thoroughbred and 6 mixed light horse type), ranging in age from 0 to 252 days, on 13 farms in central Kentucky. To detect natural infection with Eimeria leuckarti, feces were examined for oocysts. Oocysts were found in 67 (41%) of the foals on 11 (85%) of the farms. The earliest age at which oocysts were first detected was 15 days (1 foal); the latest age was 123 days (1 foal). The mean age for the first appearance of oocysts in the feces of the 67 foals positive for E leuckarti was approximately 70 days. Age of the oldest foal that passed oocysts was 185 days. The longest oocyst shedding period was about 4 months, although oocyst-positive feces usually were found only sporadically during this period.
Differential extraction of antigens of Anaplasma marginale
Authors: Adams John H. , Smith Ronald D.
Published: February 2025

Strain-, group-, and genus-specific antigens of the Florida isolate of Anaplasma marginale had different solubilities in zwitterionic, nonionic, and anionic detergents. On the basis of their solubility in nonionic detergent, antigens were grouped into 3 classes: (i) a 108-kilodalton (kD) group-specific antigen and a series of poorly defined antigens (70 to 100 kD) were completely soluble in nonionic detergent; (ii) 96 kD and 75 kD group-specific antigens, and a 91-kD strain-specific antigen were completely insoluble in nonionic detergent; and (iii) a 47-kD group-specific antigen and a 41-kD genus-specific antigen were partially soluble in nonionic detergent. A mercaptoethanol-sensitive antigen of 200 kD also was present in the insoluble fraction.

Differences in solubility of taxonomic antigens of Anaplasma may reflect differences in function. Antigens totally insoluble in nonionic detergent were possibly integral membrane proteins, and those completely soluble in nonionic detergent were more likely peripheral membrane proteins that were less tightly bound to hydrophobic components of the membrane. Seemingly, all antigens were associated with membranes. Bovine preimmune and immune sera used did not react with any proteins of noninfected rbc.
Effects of single-dose and three-day trimethoprim-sulfadiazine and amikacin treatment of induced Escherichia coli urinary tract infections in dogs
Authors: Rogers Kenita S. , Lees George E. , Simpson Russell B.
Published: February 2025

Efficacy of single-dose and 3-day trimethoprim-sulfadiazine (tms) and amikacn treatment regimens for induced Escherichia coli urinary tract infections (uti) in dogs was evaluated. Using each regimen, effects of giving tms combination or amikacin were compared in males and females, and the response of treated dogs was compared with that of nontreated controls. Response to treatment was evaluated, using results of quantitative urine cultures and urinalyses obtained on 4 occasions. Abacteriuria was identified by finding a lack of bacterial organisms in specimens collected for the initial and final posttherapy evaluations.

Before treatments, magnitudes of bacteriuria were similar in all experimental groups, and uti persisted in all nontreated dogs. Single-dose treatment regimens did not reliably eradicate uti in males or females, whether amikacin or tms was administered. Magnitude of bacteriuria often diminished immediately after single-dose treatment, and such reductions of bacteriuria persisted in 2 of 8 dogs. However, no male dogs and only 1 of 4 females became abacteriuric after a single-dose treatment regimen. The single female in which uti was eradicated was treated with a single dose of amikacin.

The 3-day tms treatment regimen eradicated uti in each of 4 females, but the 3-day amikacin treatment regimen resulted in abacteriuria in only 1 of 4 females. Three-day treatment regimens were not effective in male dogs, regardless of the antimicrobial drug used. Of the short-course treatments for canine uti evaluated by this model, only 3-day tms treatment of females was consistently effective.
Pharmacokinetics of amikacin in cats
Authors: Jernigan Antoinette D. , Wilson Robert P. , Hatch Roger C.
Published: February 2025

Six mixed-breed adult cats were given 5 mg of amikacin sulfate/kg of body weight by rapid iv, im, and sc routes of administration. The serum concentration-vs-time data were analyzed, using a noncompartmental model. The harmonic mean ± pseudo-sd of the effective half-life of amikacin was 78.8 ± 19.3 minutes after iv administration, 118.7 ± 14.4 minutes after im administration, and 117.7 ± 12.8 minutes after sc administration. The arithmetic mean ± sd of mean residence time was 118.3 ± 21.7 minutes, 173.4 ± 19.9 minutes, and 171.7 ± 19.1 minutes after iv, im, and sc drug administration, respectively. The mean apparent volume of distribution at steady state was 0.17 ± 0.02 L/kg, and the mean total body clearance was 1.46 ± 0.26 ml/min/kg. Mean bioavailability was 95 ± 20% after im administration and 123 ± 33% after sc drug administration. A recommended dosage of 10 mg/kg, q 8 h can be expected to provide a therapeutic serum concentration of amikacin with a mean steady-state concentration of 14 μg/ml. The sc route of administration is preferred, because of rapid absorption, good bioavailability, and ease of administration.
Cardiopulmonary and anesthetic effects of ketamine and its enantiomers in dogs
Authors: Muir William W. , Hubbell John A. E.
Published: February 2025

Dogs were used to determine cardiopulmonary and chemical restraining effects of racemic ketamine and its enantiomers. Levorotatory ketamine induced the shortest duration of unconsciousness and recumbency when compared with effects of dextrorotatory and racemic ketamine. Administration of racemic ketamine or either of its enantiomers (30 mg/kg of body weight, iv) to dogs recovering from isoflurane anesthesia induced transient, but significant (P < 0.05), decreases in arterial blood pressure, left ventricular contractility, cardiac output, and total peripheral vascular resistance. Arterial blood pressure and left ventricular contractility significantly (P < 0.05) increased at later times after ketamine administration. Arterial pH and the Po2 values decreased after iv administration of racemic ketamine or its enantiomers. Significant differences in cardiopulmonary variables were not observed between groups given ketamine or its enantiomers.
Percutaneous endoscopic tube gastrostomy in dogs
Authors: Bright Ronald M. , Burrows Colin F.
Published: February 2025

Percutaneous endoscopic tube gastrostomy was performed in 10 dogs, using mushroom-tip catheters (16 to 24 F) maintained in place for 5 to 32 days. Dogs were observed daily. Although placement of the catheter was simple and quick, 3 dogs destroyed their catheters. Patency of the catheter was maintained with or without regular flushings with saline solution. Pyrexia (≥ 39.4 C) developed in 3 dogs, but the rectal temperature returned to base line within 24 hours after catheter removal. After catheter removal, all wounds healed without complication. All dogs were euthanatized. Five were examined radiographically before euthanasia to determine the fate of the mushroom tip after transection of the catheter at skin level between days 5 and 21, and 5 dogs were evalated at postmortem examination between days 10 and 32. In all dogs, the tip was not present in the gastrointestinal tract by 96 hours after catheter transection. During postmortem examination of the 5 dogs, minimal inflammatory lesions were seen in the gastric tissue. A gastrocutaneous fistula had formed in each dog, resulting in an adhesion between the stomach and peritoneum.
A simple and rapid high-pressure liquid chromatographic assay for pentobarbital and other barbiturates in serum
Authors: Alila A. , Heavner J. E. , Rosenberg P. H.
Published: February 2025

A single extraction technique for measuring pentobarbital and other barbiturates in serum involved high-pressure liquid chromatography and uv detection yielding a sensitivity for pentobarbital of about 1 μg/ml. We concluded that the assay provides a practical method for use in pharmacokinetic studies and in serum concentration monitoring in experimental animals.
Effect of d-glucose on in vitro short-circuit current in neonatal calf jejunum and rabbit ileum
Authors: Ferrante Pamela L. , Freeman David E. , Whitlock Robert H. , Kronfeld David S.
Published: February 2025

Thin sheets of mucosa from small intestine of neonatal calves were mounted in incubation chambers for in vitro studies. These mucosal sheets generated a potential difference (pd) of 2.05 ± 0.02 mV (mean ± sem), short-circuit current (scc) of 23.32 ± 3.81 μA × cm -2, and tissue resistance of 86.22 ± 4.41 ohms × cm2 (n = 6). Ouabain in the serosal bathing solution caused a sharp decrease in the ssc (P < 0.01) and pd (P < 0.005), a decrease in tissue K content (P < 0.05), and an increase in tissue Na content (P < 0.05). The mucosa responded to d-glucose by an increase in pd (P < 0.001) and scc (P < 0.001). In vitro methods used in the calf were validated in similar experiments on rabbit ileum.
Characterization of canine adenovirus type 1 isolated from American black bears
Authors: Whetstone Cecelia A. , Draayer H. , Collins J. E.
Published: February 2025

Viruses recovered from tissues taken at necropsy from American black bears were examined by use of immunofluorescence with polyclonal and monoclonal antibodies, virus neutralization with monoclonal antibodies, and restriction endonuclease analyses of the viral genomes. With these techniques, viruses were determined to be canine adenovirus type 1. Seronegative dogs that were inoculated with the virus had clinical signs typical of infectious canine hepatitis, suggesting that the virus, which was virulent for bears, was not a vaccinal strain, but a wild strain of canine adenovirus type 1.
Ureterocolonic anastomosis in clinically normal dogs
Authors: Stone Elizabeth Arnold , Walter Mary C. , Goldschmidt Michael H. , Biery Darryl N. , Bovée Kenneth C.
Published: February 2025

Ureterocolonic anastomosis was evaluated in 13 clinically normal dogs. Urinary continence was maintained after surgery, and the procedure was completed without technique errors in all but 2 dogs.

Three dogs died within 5 weeks (2 of undetermined causes and 1 of aspiration pneumonia and neurologic disease), and 1 dog was euthanatized 4 months after surgery because of neurologic signs. Two healthy dogs were euthanatized 3 months after surgery for light microscopic evaluation of their kidneys. Five dogs were euthanatized 6 months after surgery for light microscopic evaluation of their kidneys. Gastrointestinal and neurologic disturbances developed in 4 dogs at various postoperative intervals. Plasma ammonia concentration measured in 2 dogs with neurologic signs was increased. Plasma ammonia concentration measured in 5 dogs without neurologic signs was within normal limits. All 5 dogs, in which metabolic acidosis was diagnosed, had high normal or above normal serum chloride concentration. Serum urea nitrogen values were increased after surgery because of colonic absorption of urea. Serum creatinine concentration was increased in 1 dog 6 months after surgery. Individual kidney glomerular filtration rate was reduced in 38% (3/8) of the kidneys from 4 other dogs at 6 months after surgery. Of 5 dogs euthanatized at 3 to 4 months after surgery, 4 had bilateral pyelitis, and 1 had unilateral pyelonephritis. Six months after surgery, pyelonephritis was diagnosed in 40% (4/10) of the kidneys from 5 dogs. The ureterocolonic anastomosis procedure is a salvage procedure that should allow complete cystectomy. However, variable degrees of metabolic acidosis, hyper-ammonemia, and neurologic disease may result.
Sources of variation introduced into a phagocytosis assay as a result of the isolation of neutrophils from bovine blood
Authors: Paape Max J. , Miller Robert H.
Published: February 2025

A study was conducted to examine sources of variation introduced into a phagocytosis assay as a result of the isolation of neutrophils from bovine blood, including variation attributable to isolation of neutrophils from blood, variation between duplicate determinations of percentage phagocytosis, and the variation in the ability of neutrophils isolated from blood (over repeated collections from the jugular vein) to phagocytose.

For the phagocytosis assay, jugular venous blood from each of 4 cows was divided into 2 equal portions. The neutrophils were isolated by lysis of red blood cells with 0.2% sodium chloride. The neutrophils (2 × 107) were incubated in duplicate with 32P-labeled Staphylococcus aureus ([32P]SA; 2 × 108) in skimmed milk samples (2.5% final concentration) prepared from 4 cows. This process was repeated thrice on neutrophils isolated from 4 cows at 2-week intervals. The proportions of variation in percentage of 32P-labeled S aureus phagocytosed between duplicate neutrophil isolations and between duplicate assay determinations were 0 and 1%. Differences among skimmed milk sources and among runs, using blood neutrophils taken at different times from the same donor cow, accounted for 62 and 36% of the total variation. The results indicated that variation arising from blood neutrophil isolation introduced into a phagocytosis assay within a single-day trial is of no concern. The large variation among skimmed milk sample sources indicated differences among cows in the ability of their milk to support phagocytosis. The variation in neutrophil isolations over time for any cow was considered too large to allow for evaluation of physiologic and environmental effects on phagocytosis of neutrophils isolated from blood.
Equine neonatal isoerythrolysis: Evidence for prevention by maternal antibodies to the Ca blood group antigen
Authors: Bailey Ernest , Albright Darrilyn G. , Henney Pamela J.
Published: February 2025

Foals with the Ca blood group antigen on their rbc were given colostrum with anti-Ca antibodies (6 foals) or colostrum without anti-Ca antibodies (6 foals). The pcv were determined at birth and 2, 4, and 6 days after birth for the foals in each group. Significant differences were not observed for the pcv between the 2 groups, indicating that foals were not adversely affected by ingesting colostrum with the anti-Ca antibody.

Standardbred mares without the Aa blood group antigen were evaluated to determine whether production of anti-Ca antibodies influenced production of anti-Aa antibodies. Of 266 mares without the Aa antigen, 3 of 61 (5%) mares without the Ca blood group antigen produced anti-Aa antibodies and 43 of 205 (21%) with the Ca blood group antigen produced anti-Aa antibodies. These 2 groups of mares were significantly (P = 0.006) different; Ca-negative mares were less likely to produce antibodies to Aa than were mares with the Ca blood group antigen. This observation was consistent with a hypothesis of antibody-mediated immunosuppression of immune response to the Aa blood group antigen by antibodies to the Ca blood group antigen, ie, when a mare is exposed to her foal's rbc and already has antibodies to the Ca blood group antigen on the foal's rbc, then she is less likely to initiate an immune response to the Aa blood group antigen also on the foal's rbc.
Effects of frequency and airway pressure on gas exchange during interrupted high-frequency, positive-pressure ventilation in ponies
Authors: Wilson D. V. , Suslak L. , Soma L. R.
Published: February 2025

Cardiovascular effects and pulmonary gas exchange were compared during conventional mechanical ventilation (cmv) and interrupted high-frequency, positive-pressure ventilation (ihfppv) in 6 anesthetized ponies in dorsal recumbency.

When the peak airway pressure (Paw) was held constant at control values attained during cmv (18 to 20 cm of H2O), and the ventilator frequency of ihfppv was varied over the range, 2.5 to 12.5 Hz, significant (P < 0.05) changes from control values were observed only in the ratio of dead-space volume to tidal volume (VD/VT) and in the respiratory minute volume (

). The mean (± sem) carbon dioxide excretion (

) was 2.12 ± 0.1 ml/kg/min during ihfppv. Dead-space ventilation ranged from 40 to 73.7% of total ventilation and increased directly with increasing frequency. The

also increased, from 89 ml/kg/min at a ventilatory frequency of 2.5 Hz to 145 ml/kg/min at a frequency of 12.5 Hz.

Maintaining the frequency of ihfppv constant at 12.5Hz and increasing the Paw over the range of 5 to 30 cm of H2O caused significant (P < 0.05) changes in arterial partial pressure of O2 (Pao2),

, pulmonary shunt fraction (QS/QT),

, arterial-alveolar differences in oxygen tension (AaDo2), VD/VT, and cardiac output, compared with cmv. The Pao2 and the

increased linearly with increasing Paw. With increasing Paw, VD/VT decreased directly with increasing Paw from 98 to 69.3%. Gas exchange at a Paw of 15 cm of H2O during ihfppv was equivalent to conditions at Paw of 20 cm of H2O during cmv. At a higher Paw during ihfppv, improvements over control values were observed in gas exchange.
Prevalence of fimbrial antigens and enterotoxins in nonclassical serogroups of Escherichia coli isolated from newborn pigs with diarrhea
Authors: Fairbrother John M. , Larivière Serge , Johnson Wendy M.
Published: February 2025

Ninety-nine nonclassical serogroups isolated from newborn pigs with neonatal diarrhea were tested for fimbrial antigens F4(K88), F5(K99), F6(987P), F41, and F165, and for heat-labile enterotoxin, heat-stable enterotoxin a (STa), heat-stable enterotoxin b, verocytotoxin, and cytolethal-distending toxin. Thirty-two strains, belonging mostly to serogroups 064:K“V142,”, O9:K103, and O20:K101, were F5-positive and usually produced STa, although 5 strains produced only heat-stable enterotoxin b. Fifteen strains, belonging mostly to serogroups 064:K“V142” and O20:K101, were F41 positive and usually produced STa. Twenty-three stains, belonging mostly to serogroups 064:K“V142,” O9:K103, and O20:K101, were F6-positive and usually produced STa. Several strains produced more than one fimbrial antigen, either F5 and F41, F5 and F6, F6 and F41, F6 and F165, or F5, F6, F41, and F165. None of the strains produced heat-labile enterotoxin, verocytotoxin, or cytolethal-distending toxin. The indirect immunofluorescence test was much more sensitive than was the slide agglutination test for the detection of each of the fimbrial antigens F5, F6, F41, and F165 on strains grown in vitro. The production of F6 by certain strains for which only a low proportion of cells were F6-positive in vitro, as demonstrated by immunofluorescence, was confirmed by experimental infection of newborn pigs.
Determination by enzyme-linked immunosorbent assay of the optimal dose of staphylococcal leukocidin for systemic immunization of dairy cows
Authors: Loeffler David A. , Norcross Neil L. , Opdebeeck Joan P.
Published: February 2025

A dose-response study was conducted to determine the optimal dose of staphylococcal leukocidin toxin to use for systemic vaccination of lactating dairy cows. Each of 5 groups of cows (8 cows/group) were given 2 injections of crude leukocidin (dose range, 9 to 2,700 mg). Antileukocidin antibody concentration in milk samples collected before vaccination and at 4 and 10 weeks after vaccination was determined by use of an elisa. The highest antibody concentration at postvaccination sample collection dates was observed in cows of the group immunized with 900 mg of leukocidin. This appeared to be the optimal vaccination dose for production of antileukocidin antibodies in the mammary gland of lactating cows.