bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of cofactor effect of feline syncytium-forming virus on feline immunodeficiency virus infection
Authors: Zenger Elisabeth , Brown Wendy C. , Song Wenru , Wolf Alice M. , Pedersen Niels C. , Longnecker Michael , Li Junzhou , Collisson Ellen W.
Published: January 2024

Although feline immunodeficiency virus (fiv) and the unrelated retrovirus feline leukemia virus (FeLV) are associated with acquired immune deficiency in cats, experimental and field evidence indicates that coinfection with both viruses may lead to more serious disease syndrome. A third feline retrovirus, feline syncytium-forming virus (FeSFV), which is far more prevalent than either fiv or FeLV and is considered nonpathogenic in nature, is consistently coisolated from sick, fiv-infected cats. To determine the potential role of FeSFV in enhancement of FIvV-mediated disease, persistent FeSFV infection was established in 14 of 24 nine-month-old cats. Four months later, half the FeSFV-infected and half the noninfected cats were inoculated with blood obtained from a cat persistently infected with the Petaluma strain of fiv. At postinoculation week 17, 1 male cat infected with only fiv died of bacterial bronchopneumonia that could have been attributed to fiv-induced acquired immune deficiency-like syndrome. However, none of the remaining cats had clinical illness, whether infected with either virus alone or coinfected with both viruses. As early as postinoculation week 6, decreases were observed in the CD4+ to CD8+ T-lymphocyte ratio of both groups of cats inoculated with fiv. Infection with FeSFV had no effect on the CD4+ to CD8+ T-cell ratio, Mitogen stimulation assays and total WBC count were unaffected by FeSFV infection, although an increase in numbers of neutrophils from FeSFV-infected cats was consistent, especially when compared with the decrease observed after fiv infection. Overall, results of the study indicate that coinfection with FeSFV may not enhance progression of the fiv-induced early stages of disease and that the positive correlation between FeSFV and fiv-induced acquired immune deficiency-like syndrome is attributable to a common mode of transmission, rather than to a synergistic effect of coinfection.
Cryopreservation of bovine buffy coat leukocytes for use in immunologic studies
Authors: Truax Robert E. , Powell Mary D. , Dietrich Marilyn A. , French Dennis D. , Ellis John A. , Newman Mark J.
Published: January 2024

A simple cryogenic technique for preserving bovine buffy coat leukocytes was developed. This was coupled with a variation of the standard discontinuous gradient technique to purify mononuclear cells that retained immunologic function. The total number of mononuclear cells recovered from cyropreserved samples were only 87 to 42% of those recovered from freshly obtained blood samples. However, the functional capabilities of mononuclear cells from cyopreserved buffy coat preparations were retained. Polyclonal proliferative responses to 3 mitogens were measured, using a titration of mitogen concentrations, and were found to be normal, compared with those of cells isolated from fresh blood. Blood samples collected after vaccination with Brucella abortus contained leukocytes that responded to irradiated B abortus. These antigen-specific responses were also retained through cyopreservation. Cell surface expression of T-lymphocyte antigens, CD2, CD4, and CD8, and cell-surface IgM on B lymphocytes was also evaluated. Flow cytometric analysis of fresh and cryopreserved mononuclear cell preparations indicated that the relative proportions of different subpopulations were not altered. The technical simplicity of our cryopreservation system will allow processing of large numbers of samples with the ability to assay various immune functions at a later time.
Critical tests of thiabendazole, oxibendazole, and oxfendazole for drug resistance of population-B equine small strongyles (1989 and 1990)
Authors: Tolliver S. C. , Lyons E. T. , Drudge J. H. , Stamper S. , Granstrom D. E.
Published: January 2024

Critical tests were conducted in horses (n = 11) with naturally acquired infections of benzimidazole(bz)-resistant population-B small strongyles in 1989 and 1990. Anthelmintics administered were thiabendazole (44 mg/kg of body weight, n = 4), oxibendazole (10 mg/kg, n = 3), and oxfendazole (ofz, 10 mg/kg; n = 4). All compounds were paste formulations administered orally except for 1 of the ofz treatments, which was a suspension formulation given by stomach tube.

Aggregate mean efficacy was calculated for all species of small strongyles, drug-resistant and non-resistant. The highest efficacy was for oxibendazole (98%) and ofz (94%); efficacy for thiabendazole was 63%.

Five genera and 16 species of small strongyles were recovered from the 11 horses, ranging from 7 to 13 species (mean, 11). Of these, 7 species were found to have resistance in variable degrees to most of the anthelmintics. These strongyles were Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus goldi, Cylicostephanus longibursatus, and Cylicostephanus minutus.

The large strongyle, Strongylus vulgaris, was present in all 11 test horses, and efficacy was 100% for all drugs. Seven of the bz-treated foals (at least 1 horse from each bz-treatment group), were infected with S edentatus; removal was 100%.
Circulatory and respiratory responses of spontaneously breathing, laterally recumbent horses to 12 hours of halothane anesthesia
Authors: Steffey E. P. , Dunlop C. I. , Cullen L. K. , Hodgson D. S. , Giri S. N. , Willits N. , Woliner M. J. , Jarvis K. A. , Smith C. M. , Elliott A. R.
Published: January 2024

Cardiovascular and respiratory changes that accompany markedly long periods (12 hours) of halothane anesthesia were characterized. Eight spontaneously breathing horses were studied while they were positioned in left lateral recumbency and anesthetized only with halothane in oxygen maintained at a constant end-tidal concentration of 1.06% (equivalent to 1.2 times the minimal alveolar concentration for horses). Results of circulatory and respiratory measurements during the first 5 hours of constant conditions were similar to those previously reported from this laboratory (ie, a time-related significant increase in systemic arterial blood pressure, cardiac output, stroke volume, left ventricular work, pcv, plasma total solids concentration, and little change in respiratory system function). Beyond 5 hours of anesthesia, arterial blood pressure did not further increase, but remained above baseline. Cardiac output continued to increase, because heart rate significantly (P < 0.05) increased. Peak inspiratory gas flow increased significantly (P < 0.05) in later stages of anesthesia. There was a significant decrease in inspiratory time beginning at 4 hours. Although PaO2 and PaCO2 did not significantly change during the 12 hours of study, increased significantly (P < 0.05) and progressively with time, beginning 6 hours after the beginning of constant conditions. Metabolic acidosis increased with time (significantly [P < 0.05] starting at 9 hours), despite supplemental iv administered NaHCO3, Plasma concentrations of eicosanoids: 6-ketoprostaglandin F1α (pgf1α a stable metabolite of pgi1), pgf2α, pge, and thromboxane (TxB2, a stable metabolite of TxA2) were measured in 5 of the 8 horses before and during anesthesia. Significant changes from preanesthetic values were not detected. Dynamic thoracic wall and lung compliances decreased with time.
Regional danofloxacin lung tissue concentrations and their relationship to regional pulmonary blood flow in consolidated and nonconsolidated bovine lung
Authors: Apley Michael D. , Upson Dan W.
Published: January 2024

Six calves with areas of pulmonary consolidation attributable to bronchopneumonia, and 6 calves with no areas of consolidation were given iv injections of danofloxacin. This injection was followed approximately 55 minutes later by injection of 15-μm radiolabeled microspheres to measure regional pulmonary blood flow.

Calves were euthanatized exactly 1 hour after the danofloxacin injection. Six samples for determination of danofloxacin concentration, each surrounded by 4 samples for determination of gamma emission counts, were taken from each lung. Additional samples focusing on the line of demarcation between consolidated and nonconsolidated tissue were taken from calves with pulmonary consolidation.

Data from calves with no areas of pulmonary consolidation indicated that blood flow was significantly reduced in the caudodorsal position of the left lung and the caudodorsal and cranioventral positions of the right lung, compared with that in other positions within the lungs. Danofloxacin concentrations in the cranioventral positions of the right and left lungs were significantly lower than those in the middle-dorsal positions.

Differences in danofloxacin concentrations and blood flow were analyzed in consolidated and nonconsolidated cranioventral and middle-ventral positions of the lungs from calves with pulmonary consolidation. Decreases in blood flow in consolidated lung tissue ranged from 83.3 to 91.7%. Danofloxacin concentrations in consolidated lung tissue were significantly reduced by 41% in the middle ventral position of the left lung.

The line of demarcation step study revealed a significant reduction of blood flow at 2 and 4 cm into consolidated lung tissue, with reductions of 84 and 88%, respectively. Danofloxacin concentration did not significantly decrease in consolidated tissue.
Gastric pH monitoring in healthy, suckling pony foals
Authors: Baker Simon J. , Gerring E. Lawrence
Published: January 2024

Gastric pH was monitored in neonatal foals from birth to 3 months of age. Background pH decreased, especially during the first week of life. Milk had complex effects that depended on pH prior to sucking, confounded by the age of the foal: nearly neutral background pH tended to be acidified after milk intake; moderately acid background pH tended to be neutralized; low background pH was only slightly increased by milk. Absolute magnitude of the effects of milk decreased with age. Existence of a proulcerative intragastric environment in preweaning foals is postulated, but this must be considered in the context of what probably is a multifactorial pathogenesis.
Determinants of glomerular ultrafiltration in cats
Authors: Brown Scott A.
Published: January 2024

To investigate the determinants of glomerular ultrafiltration, renal micropuncture studies were performed in 9 cats. Mean single nephron glomerular filtration rate (sngfr), directly measured in outer cortical nephrons, was 29.4 ± 3.0 nl/min. This was similar to the estimated value for sngfr (31.3 ± 4.6 nl/min) obtained by dividing left kidney total glomerular filtration rate (1.41 ± 0.12 ml/min/kg of body weight) by left glomerular count (175,200 ± 13,600 glomeruli/kidney). In micropuncture studies performed at mean renal perfusion pressure of 101.3 ± 1.0 mm of Hg, the glomerular capillary hydrostatic pressure was 58.0 ± 1.4 mm of Hg. The glomerular transcapillary hydrostatic pressure gradient (40.0 ± 1.8 mm of Hg) exceeded colloid osmotic pressure at the efferent end of the glomerular capillaries (28.4 ± 2.1 mm of Hg) in all cats studied, indicating existence of positive effective filtration pressure throughout the glomerular capillary bed. These results indicate that glomerular capillary pressure is sufficiently high to prevent forces from reaching filtration pressure equilibrium in feline outer cortical nephrons. Thus, the value of sngfr in feline nephrons depends on the glomerular transcapillary hydrostatic pressure gradient and the glomerular ultrafiltration coefficient.
Association between the effacing (eae) gene and the Shiga-like toxin-encoding genes in Escherichia coli isolates from cattle
Authors: Mainil Jacques G. , Jacquemin Etienne R. , Kaeckenbeeck Albert E. , Pohl Pierre H.
Published: January 2024

Two hundred ninety-six Escherichia coli isolates from feces or intestines of calves with diarrhea were hybridized with 7 gene probes. One probe (the eae probe) was derived from The eae gene coding for a protein involved in the effacement of the enterocyte microvilli by the group of bacteria called attaching and effacing E coli (aeec), and 2 probes were derived from genes coding for the Shiga-like toxins (slt) 1 and 2 produced by the verocytotoxic E coli (vtec). The other 4 probes were derived from dna sequences associated with the adhesive properties of enteroadherent E coli (eaec) to cultured cells (the eaf probe for the localized adherence pattern, probes F1845 and aida-1 for the diffuse adherence pattern, and the Agg probe for the aggregative adherence pattern). Hybridization results for the eae probe were in agreement, for all but 1 of the 8 isolates, with previously published phenotypic results of microvilli effacement. The latter was previously reported as effacing the microvilli of calf enterocytes, but was eae probe-negative. Two classes of isolates hybridized with the eae probe. Members of a first class (60 isolates) additionally produced a positive signal with 1 or both of the slt probes (vtec-aeec isolates). Isolates hybridizing with the eae and the slt1 probes were the most frequent: 56 isolates (ie, 93% of all vtec-aeec). Members of the second class (10 isolates) failed to hybridize with either slt probe (non-vtec-aeec isolates). Most isolates of these 2 classes belong to only 4 serogroups: O5, O26, O111, and O118. In addition to these 2 aeec classes, a vtec class (20 isolates) was observed. Such isolates were positive with 1 or both slt probes, but were negative with the eae probe. All but 1 isolate belonged to serogroups not found among the aeec isolates. Only 7 of all aeec and vtec isolates were positive with the eaf, the F1845, or the aida-1 probe, and none were positive with the Agg probe. On the other hand, 32 non-vtec, non-aeec isolates were positive with the F1845 probe only, 2 were positive with the eaf probe only, and 1 was positive with the aida-1 probe only, thus constituting a possible class of eaec isolates from cattle. The eae gene and the gene coding for the slt1 are, thus, associated in most aeec isolates from cattle. The isolates with other hybridization results (vtec and eaec isolates) need more work to be clearly defined.
Serogrouping of Bacteroides nodosus isolates from 62 sources in the United States
Authors: Gradin Joseph L. , Sonn Anita E. , Petrovska Liljana
Published: January 2024

Bacteroides nodosus isolates from 62 sources in the United States were obtained from sheep with infectious foot diseases. Serotypic analysis of these isolates revealed 21 serotypes (designated I-XXI). These serotypes were compared with British and Australian/ New Zealand B nodosus strains by use of reciprocal tube agglutination tests. These tests, as well as the cross-matching tube agglutination tests of the US serotypes, resulted in arranging the US serotypes into 11 serogroups, and comparing these serogroups with their Australian/New Zealand serogroup and British serotype counterparts. Three US serogroups and 1 additional British serotype had little or no relationship to any of the Australian/New Zealand serogroups A-H (the vaccine strains). One or more of these unrelated serogroups were found in 29% of the sources studied. The most frequently found US serotype was serotype XV at 29%. The most frequently found US serogroups were the serogroups analogous to serogroup B (43.5%) and serogroup H (37%); the other serogroups were found in 22.6% or less of the sources studied. Evaluation of 3 sources revealed that multiple serotypes in a single flock are common, multiple serotypes from a single lesion are possible, B nodosus isolates obtained from goats (unlike those from cattle) appear identical to the isolates obtained from sheep, and disease can appear in vaccinated animals, even in a flock that appears to be harboring only a single serogroup-B serotype (the serogroup for which there are 3 strains in the current vaccine).
Pharmacokinetics of ibuprofen in lactating dairy cows
Authors: DeGraves Fred J. , Anderson Kevin L. , Aucoin David P.
Published: January 2024

The pharmacokinetics of ibuprofen were studied in 6 adult lactating dairy cows after a single iv or oral administration of ibuprofen (25 mg/kg of body weight). Ibuprofen concentrations in milk and serum were analyzed by use of high-performance liquid chromatography. The lower limit of detection of the ibuprofen assay was 50 ng/ml.

Serum ibuprofen concentration-time curves after iv administration best fit an open two-compartment model. Harmonic mean volume of distribution at steady state was 0.14 (range, 0.12 to 0.17) L/kg, elimination half-life was 1.55 (range, 1.33 to 1.73) hours, and total clearance was 86.2 (range, 68.8 to 106.2) ml/kg/h. Harmonic mean oral bioavailability was 99% (range, 79 to 112). Adverse effects were not observed in cows given ibuprofen.
Development to blastocysts of one- to two-cell equine embryos after coculture with uterine tubal epithelial cells
Authors: Ball Barry A. , Brinsko Steven P. , Thomas Philip G. A. , Miller Paula G. , Ellington Joanna E.
Published: January 2024

Development of 1- to 2-cell in vivo fertilized equine embryos cultured with or without uterine tubal epithelial cells (utec) was studied. One- to 2-cell embryos (n = 26) were collected surgically from the uterine tubes of pony mares 1 day after ovulation. Four- to 8-cell embryos (n = 9) were collected 2 days after ovulation. Presumptive zygotes and 2-cell embryos were cultured with (n = 17) or without (n = 9) utec, and all 4- to 8-cell embryos were cocultured with utec as positive controls. Uterine tubal epithelial cells were used as cell suspensions within 2 weeks after initiation of cultures. Embryos were cultured to blastocysts or until the embryo had morphologic degeneration. Six presumptive zygotes failed to cleave in vitro. Development to blastocysts of 1-cell (4 of 11) and 2-cell (2 of 6) embryos cocultured with utec was similar. Coculture of 1- to 2-cell embryos with utec significantly (P = 0.05) improved development to blastocysts, compared with culture in medium alone (35 vs 0%, respectively); however, development to blastocysts of 1- to 2-cell embryos cocultured with utec was less (P < 0.025) than that of 4- to 8-cell embryos cocultured with utec (35 vs 89%, respectively).
Evaluation of bending strength of five interdental fixation apparatuses applied to canine mandibles
Authors: Kern Douglas A. , Smith Mark M. , Grant J. Wallace , Rockhill Amy D.
Published: January 2024

Strength in bending was determined for interdental fixation apparatuses applied to hemimandibles obtained from 24 canine cadavers. Hemimandibles were osteotomized perpendicular to the long axis between the third and fourth premolars, and segments were stabilized with 1 of 5 interdental fixation apparatuses: Erich arch bar (eab, n = 6); Stout loop (sl, n = 6); acrylic (a, n = 6); Stout loop and acrylic (sla, n = 24); and Erich arch bar and acrylic (eaba, n = 6). Ultimate strengths (mean ± sem) of eab, sl, a, sla, and eaba were 395 ± 48; 523 ± 57; 1,106 ± 102; 1,306 ± 156; and 2,707 ± 504 N·m, respectively. Stiffness (mean ± sem) of eab, sl, a, sla, and eaba were 2,944 ± 357; 6,322 ± 2,201; 16,010 ± 5,017; 15,777 ± 1,026; and 27,079 ± 5,576 N·m/ radian, respectively. Yield strengths (mean ± sem) of eab, sl, a, sla, and eaba were 66 ± 6; 264 ± 19; 911 ± 126; 1,114 ± 159; and 1,855 ± 401 N·m, respectively. There were no significant differences in acrylic weight, cross-sectional area of the acrylic, or area moment of inertia of acrylic at the osteotomy site among a, sla, and eaba; and there were no significant differences in osteotomy surface area and area moment of inertia at the osteotomy site among all apparatuses (P > 0.05). The eaba apparatus had significantly higher mean ultimate strength, mean stiffness, and mean yield strength compared to other interdental fixation apparatuses. There were no significant differences in the mean ultimate strength, mean stiffness, or mean yield strength between eab and sl (P > 0.05). Apparatuses that combine acrylic with metal reinforcement (sla, eaba) were significantly stronger and stiffer than those that used metal alone (eab, sl) or acrylic alone (A).
Scanning electron microscopy of intraocular lenses that had been implanted in dogs
Authors: Gilger Brian C. , Whitley R. David , McLaughlin Susan A. , Wright James C. , Boosinger Timothy R.
Published: January 2024

Scanning electron microscopy was used to evaluate changes on the surfaces of polymethylmethacrylate (pmma), silicone, and polyhydroxyethylmethacrylate (hema) intraocular lenses (iol) that had been implanted in the anterior chambers of the right eyes of 15 dogs. Five dogs received pmma iol; 5 dogs received silicone iol; and 5 dogs received hema iol. Twenty-eight days after surgery, the iol were removed and processed for scanning electron microscopy. Nonimplanted iol of each type were processed identically for comparison. Implanted pmma iol had significantly more debris and macrophages on their surfaces than did silicone iol or hema iol. Silicone iol had significantly less fibrin deposition than did pmma or hema iol. Silicone iol had surface defects attributable to handling by surgical instruments. Implanted hema iol had multiple pits that appeared to be caused by biodegradation.
Effect of intramuscularly administered polysulfated glycosaminoglycan on articular cartilage from equine joints injected with methylprednisolone acetate
Authors: Fubini S. L. , Boatwright C. E. , Todhunter R. J. , Lust G.
Published: January 2024

Intra-articularly administered, long-acting corticosteroids are a beneficial treatment for many equine joint disorders because they alleviate inflammation and signs of pain, but they also exert detrimental effects on the biochemical composition and morphologic features of articular cartilage. Chondroprotective drugs have been shown to mitigate some of the deleterious effects of intra-articularly administered corticosteroids on articular cartilage of laboratory animals. Twenty-one ponies were assigned at random to receive 1 of 3 treatments in the right middle carpal joint. Group-1 ponies (n = 8) had methylprednisolone acetate (mpa; 0.2 mg/kg of body weight) and saline solution administered intra-articularly and im, respectively. Group-2 ponies (n = 9) received mpa (0.2 mg/kg) and polysulfated glycosaminoglycan (gag; 2 mg/kg). Group-3 ponies (control; n = 4) had saline solution administered intra-articularly and im. The corticosteroid or saline solution was injected into the right middle carpal joint on day 1. The im administered polysulfated gag or saline solution was administered at the same time, then was repeated every 3 days for 20 days. Ponies were euthanatized 21 days after initial injection by overdose of pentobarbital sodium.

The cartilage of younger ponies was significantly (P < 0.05) more responsive to the proteoglycan-depleting effects of mpa. Ponies < 10 years old of groups 1 and 2 had significantly (P < 0.05) lower gag content in the articular cartilage than did control ponies. Systemic treatment with polysulfated gag did not result in a protective effect against proteoglycan loss from the articular cartilage. Twenty-one days after mpa injection, difference in [35S]sulfate incorporation into proteoglycan, between either mpa-treated group and the control group, was not significant. There was an approximate tenfold increase in keratan sulfate concentration in synovial fluid from mpa-treated joints, compared with control joints. Chondroprotective effect of polysulfated gag on the basis of keratan sulfate release from the articular cartilage into the synovial fluid was not observed. Methylprednisolone acetate caused a decrease in the fibronectin content of articular cartilage, but there was no effect of polysulfated gag on the fibronectin content of mpa-treated articular cartilage.
Increase of mannose residues, as Salmonella typhimurium-adhering factor, on the cecal mucosa of germ-free chickens infected with Eimeria tenella
Authors: Baba Eiichiroh , Tsukamoto Yasutaka , Fukata Tsuneo , Sasai Kazumi , Arakawa Akira
Published: January 2024

To study increase of the Salmonella population in the cecum of chickens infected with Eimeria te-nella, changes in mannose residues on the cecal mucosa were investigated. Inhibition of S typhimurium adherence to the cecum by a 2% carbohydrate (d-mannose, d-galactose, l-fucose, α-methyl- d-glucoside) in phosphate-buffered saline solution was examined. Only d-mannose had inhibitory effects. Whereas d-galactose had somewhat enhancing effects on adherence of S typhimurium to the cecal mucosa of uninfected germ-free chickens. In infected and uninfected chickens, d-mannose inhibited adherence of Styphimurium. d-Mannose significantly (P< 0.05) increased adherence of Bacteroides sp. In infected and uninfected chickens, d-mannose did not have any effect on adherence of Clostridium perfringens and Bifidobacterium thermophilum. Under microscopic observation, only concanavalin A and Lens culinaris agglutinin, of 8 lectins examined, were recognized as lectin-positive staining lines or spots in the cecal mucosa, indicating presence of mannose residues on the cecal mucosa. In E tenella-infected chickens, lectin-positive staining was seen strongly on the coarse surface of damaged cells and at the bottom of the crypts. These results indicate that coccidial infection may induce increase of mannose residues on the intestinal surface and allow adhesion of more salmonellae to the intestine.
In vitro antibacterial activity of cefoxitin and cefotetan and pharmacokinetics in dogs
Authors: Petersen Steven W. , Rosin Eberhard
Published: January 2024

The susceptibility of 50 clinical Escherichia coli isolates to various antibacterials, including cefoxitin and cefotetan was ascertained, and the minimal inhibitory concentration (mic) of cefoxitin and cefotetan for each of these isolates was determined. The pharmacokinetics of cefoxitin and cefotetan after a single iv or sc injection (30 mg/kg of body weight) were determined in 4 dogs. Of the 50 E coliisolates, 98% were susceptible in vitro to cefotetan, 90% were susceptible to cefoxitin, and 88% were susceptible to gentamicin. The mic that would inhibit the growth of 90% of the E coliisolates (mic90) was 0.25 µg/ml for cefotetan and 4 µg/ml for cefoxitin. Plasma cefotetan concentrations remained above mic90 for (mean ± SD) 8.2 ± 1.72 8.2 ± 1.72 hours and 13.52 ± 0.28 hours after iv and sc administration, respectively. Plasma cefoxitin concentrations remained above mic90 for (mean ± SD) 5.37 ± 1.18 hours and 7.95 ± 0.71 hours after iv and sc administration, respectively. We concluded that cefotetan was superior to cefoxitin·was superior to cefoxitin in activity against E coli in vitro. We recommend that cefotetan be given at a dosage of 30 mg/kg, iv, every 8 hours, Or sc, every 12 hours.
Comparison of flunixin, prednisolone, dimethyl sulfoxide, and a lazaroid (U74389F) for treating endotoxemic neonatal calves
Authors: Semrad Susan D.
Published: January 2024

Saline (0.9% NaCl) solution, flunixin meglumine (1.1 mg/kg), prednisolone sodium succinate (1.1 mg/ kg), U74389F (1.5 mg/kg), and dimethyl sulfoxide (0.5 g/kg) were each administered FV to 5 neonatal calves 15 minutes after the start of a 3-hour infusion of Escherichia coli lipopolysaccharide (lps; 2 µg/kg/hr). Four additional calves were given a 3-hour IV infusion of saline solution alone. Only flunixin significantly suppressed eicosanoid production and mitigated clinical signs associated with endotoxemia. Prednisolone provided partial protection against lps-induced hypotension and lacticemia. Pronounced hypoglycemia and lacticemia were observed in U74389F-treated calves; LPS-induced hypotension and hypoglycemia were marked in dimethyl sulfoxide-treated calves.
Immune responses and protection against infection and abortion in cattle experimentally vaccinated with mutant strains of Brucella abortus
Authors: Cheville N. F. , Stevens M. G. , Jensen A. E. , Tatum F. M. , Halling S. M.
Published: January 2024

Twenty-four 10-month-old Polled Hereford heifers were inoculated sc with live cells of one of the following strains of Brucella abortus: S19Δ31K (n = 4), S19ΔSOD (n = 4), RB51 (n = 4), and strain 19 (n = 6); controls (n = 6) were given saline solution. Heifers given the deletion mutants S19Δ31K and S19ΔSOD, and those given strain 19 developed antibody responses to B abortus and cutaneous reactions to brucellin. Heifers given strain RB51 did not develop antibodies that reacted in the standard tube agglutination test, but sera reacted in tests, using an antibody dot-blot assay containing RB51 antigen. The S19Δ31K and S19ΔSOD strains of B abortus isolated from lymph node tissue after vaccination did not differ genetically from the master stock strain. All heifers were bred naturally at 16 to 17 months of age, and were challenge-exposed intraconjunctivally with virulent B abortus strain 2308 during the fifth month of pregnancy. All vaccinated heifers were protected (ie, none aborted and none had B abortus isolated from their tissues after parturition). Calves born from vaccinated dams were free of B abortus. Antibody responses in heifers after challenge exposure were an indicator of immunity. All 5 control heifers (nonvaccinated) developed serum antibodies after challenge exposure; 3 aborted, and 1 delivered a small, weak calf at 8.5 months of gestation. Thus, live mutant strains of B abortus can induce protective immunity when given at 10 months of age, and strain RB51 is a strong candidate for further testing.
Antigenic and genetic analysis of a recently isolated H1N1 swine influenza virus
Authors: Olsen Christopher W. , McGregor Martha W. , Cooley A. James , Schantz Brian , Hotze Brian , Hinshaw Virginia S.
Published: January 2024

Hemagglutinins (ha) of H1N1 swine influenza viruses isolated in the United States have remained antigenically and genetically conserved for many years. In contrast to such conservation, the ha of A/Swine/Nebraska/1/92 (Sw/Neb) could readily be distinguished from those of contemporary porcine viruses. Twenty-eight amino acid mutations differentiated the ha of Sw/Neb and A/Swine/Indiana/1726/88, the most recent H1N1 swine influenza virus for which ha sequence data were available. Among these differences were mutations at potential asparagine-linked glycosylation sites and charge changes at many residues. The Sw/Neb virus also could be differentiated from other swine influenza viruses in hemagglutination-inhibition assays with monoclonal antibodies to recent Hl swine ha. Nonetheless, overall sequence analysis of the ha and the nucleoprotein genes of Sw/Neb indicated that this virus was more closely related genetically to classic H1N1 swine influenza viruses than to H1N1 avian or human viruses. Infection of swine with Sw/Neb under experimental conditions induced clinical signs and lesions typical of swine influenza. However, affected swine in the field had high, persistent fevers, but relatively mild signs of respiratory tract disease. This study indicated that an antigenically and genetically novel variant of swine influenza virus was detected in the United States.
Use of random fragments of chromosomal DNA to highlight restriction site heterogeneity for fingerprinting isolates of Salmonella typhimurium from hospitalized animals
Authors: Hansen Lori M. , Jang Spencer S. , Hirsh Dwight C.
Published: January 2024

Random fragments of dna were obtained from a cosmid library of Salmonella agona genomic dna. From this library, 2 fragments were chosen and pooled to probe isolates of S typhimurium obtained during an episode of salmonellosis in a veterinary medical teaching hospital. Chromosomal dna from the Salmonella isolates was digested with restriction endonucleases, and was probed with the random fragments of chromosomal dna. This procedure resulted in a fingerprint pattern for each isolate. We found that the method permitted discrimination between isolates involved in the disease episode and S typhimurium obtained prior to the episode. We conclude that random fragments of chromosomal dna are useful for fingerprinting isolates of S typhimurium. Analysis of plasmid dna obtained from the isolates was not as useful. Some isolates found to be identical by restriction site analysis, had plasmids of different molecular weight. These results indicate that plasmid analysis may not be as useful a fingerprinting tool as previously reported.
Serologic and parasitologic responses of domestic chickens after oral inoculation with Toxoplasma gondii oocysts
Authors: Dubey J. P. , Ruff M. D. , Camargo M. E. , Shen S. K. , Wilkins G. L. , Kwok O. C. H. , Thulliez P.
Published: January 2024

Four-week-old chickens were inoculated orally with 1,000 or 100,000 oocysts of the ME-49 or GT- 1 strain of Toxoplasma gondii, and their antibody responses were measured, using the direct modified agglutination test, latex agglutination test, indirect hemagglutination test, elisa, and the Sabin-Feldman dye test. Antibodies against T gondii were detected by use of the modified agglutination test and elisa within 2 weeks of oocyst inoculation, and antibodies persisted until termination of the study by postinoculation day 68. The latex agglutination test was insensitive in detecting T gondii antibodies, and antibodies were not detected by use of the dye and indirect hemagglutination tests. Of tissues bioassayed in mice for tissue cysts by pepsin digestion of individual organs of chickens on postinoculation day 68, tissue cysts were found in the brain of all 5, heart of 3, and leg muscles of 2, but not in the liver and breast muscles. None of the birds developed clinical toxoplasmosis.
Influence of anesthetic regimens on the perioperative catecholamine response associated with onychectomy in cats
Authors: Lin H. C. , Benson G. J. , Thurmon J. C. , Tranquilli W. J. , Olson W. A. , Bevill R. F.
Published: January 2024

Plasma catecholamine concentrations in response to onychectomy were examined in 27 cats receiving different anesthetic regimens. Each cat was anesthetized with a dissociative-tranquilizer combination, and onychectomy was performed on 1 forefoot. One week later, each cat was anesthetized with the same dissociative-tranquilizer combination plus either butorphanol or oxymorphone, and onychectomy was performed on the other forefoot. Four treatment groups were studied: tiletamine-zolazepam and tiletamine-zolazepam-butorphanol combinations were administered to group-1 cats, ketamine-acepromazine and ketamine-acepromazine-butorphanol combinations were administered to group-2 cats, tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone combinations were administered to group-3 cats, and ketamine-acepromazine and ketamine-acepromazine-oxymorphone combinations were administered to group-4 cats. All drug combinations were administered im. Central venous blood samples were drawn for catecholamine analysis after injection of drug(s), after onychectomy, and 1, 2, and 4 hours after injection. Tiletamine-zolazepam alone or tiletamine-zolazepam-butorphanol prevented epinephrine release for 2 hours after injection of drug(s). Norepinephrine concentration increased significantly (P < 0.05) from baseline after onychectomy for tiletamine-zolazepam-butorphanol and at 4 hours for tiletamine-zolazepam and tiletamine-zolazepam-butorphanol. After onychectomy, there was no difference in epinephrine values between tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone. Ketamine-acepromazine prevented increases in norepinephrine and epinephrine concentrations for up to 2 hours after surgery. Addition of butorphanol to ketamine-acepromazine decreased norepinephrine values immediately after onychectomy. Addition of oxymorphone to ketamine-acepromazine resulted in lower epinephrine values 4 hours after surgery.
Measurement of pulmonary diffusing capacity for carbon monoxide and functional residual capacity during rebreathing in conscious Thoroughbreds
Authors: Aguilera-Tejéro Escolastico , Pascoe John R. , Amis Terrence C. , Kurpershoek Cornelis J. , Woliner Michael J.
Published: January 2024

A rebreathing method for measurement of pulmonary diffusing capacity for carbon monoxide (DlCO) and functional residual capacity (frc) was evaluated in conscious horses. Horses were manually ventilated through an endotracheal tube, using a custom-made syringe filled with a gas mixture containing 18-carbon monoxide (18CO) and helium (He). The 18CO and He concentrations were continuously monitored by use of a mass spectrometer connected to the rebreathing circuit. Values for DlCO and frc were calculated from changes in the concentration of these 2 gases. In 11 Thoroughbreds, mean (± sd) DlCO was 330.3 ± 56.9 ml•min−1•mm of Hg−1, and frc was 20.21 ± 3 35 L. Body weight normalization yielded mean (± sd) values of 0.652 ± 0.114 ml•min−1•mm of Hg−1•kg−1 for DlCO, and 39.9 ± 6.4 ml•kg−1 for frc.
Influence of hydration state on renal functions of dogs
Authors: Tabaru Hideki , Finco Delmar R. , Brown Scott Alan , Cooper Tanya
Published: January 2024

Clinically normal dogs were evaluated in states of dehydration, euhydration, and after fluid administration to determine effects of hydration state on renal clearance values. Endogenous creatinine, exogenous creatinine, and [14C]inulin clearances, were determined to measure glomerular filtration rate (gfr); in some experiments p-aminohippurate clearance was determined to measure renal plasma flow.

Dehydration caused significant (P < 0.05) decrease in clearance values, compared with euhydration, and clearance values during euhydration were significantly (P < 0.05) less than values obtained after a single gavage with water (30 ml/kg of body weight).

Sustained administration of 3 fluid regimens was evaluated for effects on clearance values (treatment A = 30 ml of lactated Ringer’s solution/kg/h; treatment B = 30 ml of water/kg by gavage hourly; treatment C = 10 ml of glucose:lactated Ringer’s solution/kg/h). All regimens of fluid therapy caused significant P < 0.05), progressive increases in gfr, but treatment C resulted in the most stable gfr values. Increases in clearance values were associated with positive fluid balance; the rate of fluid administration was greater than the rate of urine formation.

Data from 285 gfr determinations on 85 dogs were evaluated retrospectively. For each determination, three 20-minute urine collections were made beginning 40 minutes after 30 ml of water/kg was given by gavage. Values between collections were significantly (P < 0.05) different, but varied by < 3%.

Comparison of methods for measurement of gfr indicated that endogenous creatinine clearance and [14C]inulin clearance were highly correlated (R2 = 0.82), but mean clearance values were markedly different (mean ± sem, 28.70 ± 0.01 and 37.07 ± 1.29 ml/min, respectively).

Exogenous creatinine clearance and [14C]inulin clearance were highly correlated (R2 = 0.95), and mean values were 40.54 ± 0.70 and 41.02 ± 0.70 ml/min respectively.

We conclude that: state of hydration has a marked effect on gfr; rate of fluid administration that exceeds rate of urine production results in progressive increases in gfr; a single water gavage of 30 ml/kg gives stable gfr values for three 20-minute collection periods, may avoid subclinical states of dehydration, and facilitates accurate urine collections; and endogenous creatinine clearance, as conducted in this study, does not accurately measure gfr.
Circulating concentration of dexamethasone in healthy dogs, dogs with hyperadrenocorticism, and dogs with nonadrenal illness during dexamethasone suppression testing
Authors: Kemppainen Robert J. , Peterson Mark E.
Published: January 2024

Concentration of dexamethasone was determined in plasma or serum samples from dogs after iv administration of a low dose (0.01 mg/kg of body weight) or high dose (0.1 mg/kg) of dexamethasone. On the basis of history, clinical signs of disease, and degree of cortisol suppression in response to dexamethasone, dogs were assigned to these groups: healthy dogs, dogs with nonadrenal illness, and dogs with hyperadrenocorticism. Four hours after administration of the low dose of dexamethasone, concentration of the steroid was reduced (P < 0.05) in dogs with hyperadrenocorticism, compared with healthy dogs, but not compared with values from dogs with nonadrenal illness. By 8 hours after dexamethasone administration, values were similar across groups. Dexamethasone concentration 4 and 8 hours after high-dose administration was similar between healthy dogs and dogs with hyperadrenocorticism. Concentration of dexamethasone 4 and 8 hours after its administration overlapped after the 2 doses. For example, in 11 of 66 dogs from all groups, concentration measured 4 hours after the low dose was greater than the minimal concentration determined in the 18 dogs given the high dose. These data indicate that dexamethasone metabolism may be altered in dogs with hyperadrenocorticism, and that individuals may have appreciable variability in dexamethasone clearance. Such variability provides a possible explanation for false-positive and false-negative results associated with dexamethasone suppression testing in dogs.
Effects of vena caval banding in experimentally induced multiple portosystemic shunts in dogs
Authors: Butler-Howe Lisa M. , Boothe Harry W. , Boothe Dawn M. , Laine Glen A. , Calvin James A.
Published: January 2024

Effects of vena caval banding on portal venous and vena caval hemodynamics were examined in 6 control dogs and in 10 dogs that had undergone attenuation (banding) of the abdominal part of the caudal vena cava and had dimethylnitrosamine-induced multiple portosystemic shunts (pss). Additionally, indocyanine green (icg) extraction and clearance after infusion to steady state were used to calculate hepatic plasma flow in these dogs. Sixteen dogs were randomly assigned to 2 groups: control (n = 6) or diseased(n= 10). Diseased dogs were administered dimethylnitrosamine (2 mg/kg, po, twice weekly) until multiple pss developed, as assessed by results of clinical laboratory tests, ultrasonography, and hepatic scintigraphy. Shunts were confirmed visually at celiotomy and by contrast portography. Venous pressures (caudal vena caval, portal, and hepatic) were recorded before and after vena caval banding for up to 7 days in dogs from both groups. Peritoneal cavity pressures were recorded in all dogs after closure of the body wall. To determine icg extraction and clearance, a bolus injection of icg (0.5 mg/kg, iv) was administered, followed by steady-state infusion of 0.097 mg/min. Extractions and clearances of icg were measured, and from these, hepatic plasma flow rates were determined immediately before and after banding and at 6 hours, 48 hours, and 7 days after banding.

The gradient (caudal vena caval pressure within 1 to 2 mm of Hg of portal pressure) between caudal vena cava and portal venous pressures established at banding was maintained after the first hour in both groups. Caudal vena cava pressures established at banding were maintained throughout the study, with the exception of the first hour in diseased dogs. Extraction ratios were higher in control dogs at all times, except at 48 hours. Clearance was higher in control dogs at all times. Hepatic plasma flow did not differ between groups, except immediately after banding, when flow was greater in diseased dogs, and differences were not found over time in either group. This study indicated that vena caval banding in this model of experimentally induced multiple pss increases and maintains caudal vena cava pressure, relative to portal venous pressure (after the first hour) for 7 days, and that calculated hepatic plasma flow is not persistently improved by vena caval banding.
Sensitivity and specificity of bronchoalveolar lavage and protected catheter brush methods for isolating bacteria from foals with experimentally induced pneumonia caused by Klebsiella pneumoniae
Authors: Hoffman Andrew M. , Viel Laurent , Staempfli Henry R. , Muckle Catherine A. , Yager Julie A.
Published: January 2024

One indication for referral of horses to veterinary hospitals is for diagnosis of the microbiologic cause of pneumonia, particularly when the initial treatment fails. Although endoscopic methods have long been available for microbiologic sample collection, accuracy of these methods under these conditions have not been studied in detail. We compared the bacteria isolated from samples obtained by bronchoalveolar lavage (bal) with those obtained by protected catheter brush (pcb) from foals with unilateral pneumonia induced by inoculation with Klebsiella pneumoniae. As part of previously described clinical trials, foals were administered antimicrobial therapy im (n = 15) or vehicle im (n = 7), and collection of distal airway secretion samples was conducted during the treatment period. Sensitivity and specificity of the sample collection methods were assessed by comparison of the isolates from bal or pcb samples with isolates from tissue of the inoculated lung lobe, which was the most severely affected lung region. Sensitivity and specificity of bal for recovery of K pneumoniae (challenge strain) and Streptococcus zooepidemicus (common secondary pathogen) was 90 and 69%, respectively, compared with 76 and 85%, respectively, for the pcb method. Sensitivity was significantly (P = 0.03) higher for bal (100%) than for pcb (69%) for recovery of K pneumoniae (P = 0.03) from lungs. However, difference in the sensitivity of these methods for recovery of S zooepidemicus was not significant. In conclusion, bal was a more reliable method for recovery of bacteria from the lungs in chronically infected foals that received antimicrobial treatment.
Automated morphometric analysis of stallion spermatozoa
Authors: Davis Russell Oren , Gravance Curtis Guy , Casey Patrick Joseph
Published: January 2024

Tissue variation in microscope slides made for spermatozoon analysis and variation introduced by the subjective techniques used to analyze these slides reduce the statistical power of studies that seek to use spermatozoon morphology to predict fertility. A simple specimen preparation method was developed to standardize stallion spermatozoon morphologic smears, and a new, automated spermatozoa morphometry instrument was used to objectively analyze the efficacy of the specimen preparation technique. The method achieved a standard spermatozoon concentration and reduced field-to-field variation in the number of spermatozoa analyzed. Metric measurements of spermatozoon head dimensions from clinically normal, fertile stallions revealed small, but highly significant, differences between stallions. The variation in metric measurements between replicate slides within stallions was small, indicating that replicate slide analysis probably is not necessary for clinically normal stallions. Coefficients of variation were generally < 11% for metric measurements between stallions, and were < 4% within stallions. This study revealed that a high degree of statistical power can be achieved when using these new, standardized specimen preparation and objective analysis techniques. Such power makes possible the detection of subtle differences between clinically normal stallions, and may facilitate accurate detection of abnormal fertility (ie, subfertility) installions.