bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum amylase activity and calcium and magnesium concentrations in young cattle grazing fescue and Bermuda grass pastures
Authors: Nutting David F. , Tolley Elizabeth A. , Toth Linda A. , Ballard Steve D. , Brown Michael A.
Published: January 2024

The study reported here was part of a long-term investigation of the effects of genotype on growth, reproduction, and metabolism in cattle grazing common Bermuda grass and endophyte-infected fescue pastures. In June 1990, blood samples were collected from the tail vein of yearling heifers and steers (Angus [aa], Brahman [bb], and their reciprocal crosses [ab, ba], n = 97). Serum amylase activity was assayed enzymatically; serum Ca and Mg concentrations were determined by atomic absorption spectrophotometry. The effects of endophyte-infected fescue depended on genotype (P < 0.001). In yearlings having at least 1 Angus parent (aa, ab, ba), grazing endophyte-infected fescue was associated with higher serum amylase activity than was grazing Bermuda grass. But serum amylase activities of bb yearlings consuming either forage were similar. Moreover, for either forage, substantial differences were related to genotype (P < 0.007) and gender (P < 0.05). Angus yearlings had higher serum amy-lase activity than did Brahman yearlings; ab and ba yearlings had intermediate values. Heifers had higher amylase activity than did steers. The relationship among serum values of amylase, Ca, and Mg depended on forage. Yearlings consuming endophyte-infected fescue and hav-ing at least 1 Angus parent had a moderate negative correlation between serum amylase activity and Ca concentration (r = —0.53; P < 0.0005); that is, in calves of genotypes with increased amylase activity while consuming endophyte-infected fescue (aa, ab, ba), the higher the amylase activity, the lower the serum Ca concentration. However, in yearlings consuming Bermuda grass, serum amylase and Ca values were not correlated. Conversely, grazing Bermuda grass was associated with moderate positive correlation between Ca and Mg concentrations (r = 0.46; P < 0.0003), but in yearlings grazing endophyte-infected fescue, Ca and Mg concentrations were independent. The cause, pathophysiologic mechanism, and clinical importance of these effects remain to be determined. In conclusion, serum amylase activity in yearling cattle was influenced by genotype, gender, and consumption of endophyte-infected fescue. We speculate that yearlings having at least 1 Angus parent may develop a persistent subclinical derangement of the exocrine portion of the pancreas when exposed to common environmental toxins associated with endophyte-infected fescue grass, and that purebred Brahman yearlings can resist this aspect of fescue toxicosis.
Acute effects of a γ-glutamylated derivative of S-(1,2-dichlorovinyl)-l-cysteine on renal function and ultrastructure in pentobarbital-anesthetized dogs: Site-specific toxicity involving S1 and S2 cells of the proximal tubule
Authors: Ridgewell Richard E. , Krejci Mark E. , Koechel Daniel A.
Published: January 2024

It has been established that l-γ-glutamylated derivatives of α-amino acids are delivered more efficiently to the kidneys than are the parent α-amino acids. Therefore, we synthesized L-γ-glutamyl-S-(1,2-dichlorovinyl)-l-cysteine (L-γ-glutamyl-l-dcvc), the simplest l-γ-glutamylated derivative of the nephrotoxic α-amino acid S-(1,2-dichlorovinyl)-l-cysteine (l-dcvc), and investigated its effects on renal function and ultrastructure in pentobarbital-anesthetized dogs. Intravenous doses of 23.15 and 92.60 (μmol of L-γ-glutamyl-l-dcvc/kg of body weight induced significant increases in urinary protein output and significant decreases in the clearance of inulin during the 6-hour post-injection period. Changes were not observed in any of the other 13 renal function variables or in the 11 plasma and blood variables that were monitored throughout the same period. Both doses of L-γ-glutamyl-l-dcvc induced renal ultrastructural lesions in the S1 and S2 cells of the canine proximal tubule; the remaining 8 cell types downstream and the glomeruli were not damaged. The onset and magnitude of renal function changes and the cell types affected by L-γ-glutamyl-l-dcvc were virtually identical to those observed previously following iv administration of equivalent doses of l-dcvc to pentobarbital-anesthetized dogs. Rapid removal of the l-γ-glutamyl group from L-γ-glutamyl-l-dcvc (ie, deglutamylation) resulting in formation of the parent α-amino acid, l-dcvc, can best explain the extreme similarity in the nephrotoxic profiles of these 2 toxicants.
Relation of fructosamine to serum protein, albumin, and glucose concentrations in healthy and diabetic dogs
Authors: Kawamoto M. , Kaneko J. J. , Heusner A. A. , Feldman E. C. , Koizumi I.
Published: January 2024

The relation of the glycated serum protein, fructosamine, to serum protein, albumin, and glucose concentrations was examined in healthy dogs, dogs with hypo- or hyperproteinemia, and diabetic dogs. Fructosamine was determined by use of an adaptation of an automated kit method. The reference range for fructosamine in a composite group of control dogs was found to be 1.7 to 3.38 mmol/L (mean ± sd, 2.54 ± 0.42 mmol/L). Fructosamine was not correlated to serum total protein, but was highly correlated to albumin in dogs with hypoalbuminemia. To normalize the data with respect to albumin, it is suggested that the lower limit of the reference range for albumin concentration (2.5 g/dl) be used for adjustment of fructosamine concentration and only in hypoalbuminemic dogs. In 6 hyperglycemic diabetic dogs, fructosamine concentration was well above the reference range. It is concluded that although fructosamine may be a potentially useful guide to assess the average blood glucose concentration over the preceding few days in dogs, further study is required to establish its value as a guide to glucose control in diabetic dogs.
Effects of intracameral injection of tissue plasminogen activator on corneal endothelium and intraocular pressure in dogs
Authors: Gerding Paul A. , Essex-Sorlie Diane , Yack Robert , Vasaune Steven
Published: January 2024

Contact wide-field specular microscopy was performed on eyes of 16 healthy dogs after tissue plasminogen activator at a concentration of 25 μg/100 μl (group 1, n = 8) or 50 μg/100 μl (group 2, n = 8) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Applanation tonometry was used to measure intraocular pressure in both eyes for up to 168 hours. By use of computerized morphometric analysis and pachymetry, changes from baseline values in endothelial cell density, cell morphologic features, and corneal thickness were evaluated at postinjection hours 24, 48, and 168. Significant mean differences in intraocular pressure were not detected between treated eyes of group-1 dogs and those in group 2 at designated times, or between treated and nontreated eyes of dogs in either group. Mean corneal thickness of treated and nontreated eyes was similar in both groups through postinjection hour 168. Changes in mean percentage of endothelial cell sides were observed only in treated eyes of group-2 dogs, with the mean percentage of hexagons at postinjection hour 168 decreasing by 18%, a decrease that was significantly (P < 0.05) greater than the decrease in nontreated eyes. The mean percentage of 6-sided cells in treated eyes of group-2 dogs was significantly (P < 0.05) less than that in treated eyes of group-1 dogs at postinjection hour 168.
Detection of hemorrhagic septicemia virus of salmonid fishes by use of an enzyme-linked immunosorbent assay containing high sodium chloride concentration and two noncompetitive monoclonal antibodies against early viral nucleoproteins
Authors: Sanz Fernando A. , Coll Julio M.
Published: January 2024

Inclusion of high-ionic strength buffers helped us to develop a sandwich elisa to detect hemorrhagic septicemia virus (hsv) in cell culture and infected trout tissue extracts. For maximal sensitivity of 0.1 to 0.2 ng/well/100 μl or about 10 to 50 tcld50/well/100 μl, trout extracts were diluted 1:1 and assayed for the earliest synthesized nucleoprotein N. Simultaneous binding of the N protein from hsv in the sample to the wells coated with monoclonal antibody (2D5 against the N protein) and to the peroxidase-labeled monoclonal antibody (2C9 against the N protein) proceeded during a 2-hour incubation at 20 to 22 C (room temperature). The response was linear between 6 to 60 ng/well of purified virus. Monoclonal antibodies used were noncompetitive with each other and reacted with F1, F2, 23.75, and 5 Spanish isolates of hsv, but not with infectious hematopoietic necrosis or infectious pancreatic necrosis viruses. Tissue specimens with low content of hsv virus may now be assayed directly without use of cell culture, rapidly, and with high precision, during the acute phase of the disease in salmonid fishes.
Effects of xylazine on ventilation in horses
Authors: Lavoie J. P. , Pascoe J. R. , Kurpershoek C. J.
Published: January 2024

The effects of 3 commonly used dosages (0.3, 0.5, and 1.1 mg/kg of body weight, iv) of xylazine on ventilatory function were evaluated in 6 Thoroughbred geldings. Altered respiratory patterns developed with all doses of xylazine, and horses had apneic periods lasting 7 to 70 seconds at the 1.1 mg/kg dosage. Respiratory rate, minute volume, and partial pressure of oxygen in arterial blood () decreased significantly (P < 0.001) with time after administration of xylazine, but significant differences were not detected among dosages. After an initial insignificant decrease at 1 minute after injection, tidal volume progressively increased and at 5 minutes after injection, tidal volume was significantly (P < 0.01) greater than values obtained before injection. Partial pressure of carbon dioxide in arterial blood () was insignificantly increased. After administration of xylazine at a dosage of 1.1 mg/ kg, the mean maximal decrease in was 28.2 ± 8.7 mm of Hg and 22.2 ± 4.9 mm of Hg, measured with and without a respiratory mask, respectively. Similarly, the mean maximal increase in PaCO2 was 4.5 ± 2.3 mm of Hg and 4.2 ± 2.4 mm of Hg, measured with and without the respiratory mask, respectively. Significant interaction between use of mask and time was not detected, although the changes in PaO2 were slightly attenuated when horses were not masked. The temporal effects of xylazine on ventilatory function in horses should be considered in selecting a sedative when ventilation is inadequate or when pulmonary function testing is to be performed.
Effects of Ehrlichia phagocytophila infection on serum thyroid hormone concentrations and on antipyrine clearance and metabolite formation in dwarf goats
Authors: Offiah Veronica N. , Nijmeijer Sandra M. , van Duin Cock T. M. , Witkamp Renger F. , van Miert Adelbert S. J. P. A. M.
Published: January 2024

The influence of infection with Ehrlichia phagocytophila (ep) on serum thyroid hormone concentrations and on antipyrine (25 mg/kg of body weight, iv) plasma elimination and urinary metabolite excretion was studied in castrated male dwarf goats. Mean thyroid hormone concentrations moderately decreased in ep-infected goats, with maximal decrease in total and free triiodothyronine and thyroxine serum concentrations of 56, 64, 23, and 19%, respectively. The estimated pharmacokinetic values of antipyrine (ap) in ep-infected goats were similar to those in the goats when healthy. However, glucuronidation of the ap-metabolites 3-hydroxymethyl-ap, 4,4′-dihydroxy-ap, and 4-hydroxy-ap was reduced during the febrile episode of the acute-phase response to ep infection.
Efficacy of orally administered moxidectin against naturally acquired gastrointestinal nematodes in cattle
Authors: Zimmerman Gary L. , Hoberg Eric P. , Pankavich John A.
Published: January 2024

Anthelmintic efficacy of moxidectin, an experimental antiparasitic macrocyclic lactone, was evaluated in a group of 15 calves harboring naturally acquired gastrointestinal nematodes. Three groups of 5 calves each served as untreated controls (group 1) or principals that were given moxidectin po at the rate of 0.2 mg/kg (group 2) or 0.4 mg/kg (group 3) of body weight. Equal numbers of control and treated calves were necropsied for parasite recovery on days 10 (3 control and 3 of each treatment group) and 11 (2 control and 2 of each treatment group) after treatment. Efficacies at both doses were > 99.8 and 99.9% against active and inhibited larvae and adults of Ostertagia spp, respectively. The overall mean efficacy of each dose was > 99.9%.
Pathogenicity of porcine enterotoxigenic Escherichia coli that do not express K88, K99, F41, or 987P adhesins
Authors: Casey Thomas A. , Nagy Bela , Moon Harley W.
Published: January 2024

Three-week-old weaned and colostrum-deprived neonatal (< 1 day old) pigs were inoculated to determine the pathogenicity of 2 enterotoxigenic Escherichia coli isolates that do not express K88, K99, F41, or 987P adhesins (strains 2134 and 2171). Strains 2134 and 2171 were isolated from pigs that had diarrhea after weaning attributable to enterotoxigenic E coli infection. We found that both strains of E coli adhered in the ileum and caused diarrhea in pigs of both age groups. In control experiments, adherent bacteria were not seen in the ileum of pigs < 1 day old or 3 weeks old that were noninoculated or inoculated with a nonpathogenic strain of E coli. These control pigs did not develop diarrhea. Antisera raised against strains 2134 and 2171 and absorbed with the autologous strain, grown at 18 C, were used for bacterial-agglutination and colony-immunoblot assays. Both absorbed antisera reacted with strains 2134 and 2171, but not with strains that express K99, F41, or 987P adhesins. A cross-reaction was observed with 2 wild-type K88 strains, but not with a K12 strain that expresses K88 pili. Indirect immunofluorescence with these absorbed antisera revealed adherent bacteria in frozen sections of ileum from pigs infected with either strain. We concluded that these strains are pathogenic and express a common surface antigen that may be a novel adhesin in E coli strains that cause diarrhea in weaned pigs.
Serum free and total iodothyronine concentrations in dogs with hyperadrenocorticism
Authors: Ferguson Duncan C. , Peterson Mark E.
Published: January 2024

Serum concentrations of total and free thyroxine (T4 and FT4, respectively), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (reverse T3) were measured in 42 dogs with hyperadrenocorticism, and were compared with values determined in clinically normal dogs. Mean total T4 concentration in dogs with hyperadrenocorticism (14.3 nmol/L) was significantly (P < 0.001) lower than the normal value (25.7 nmol/L), with 38% of the dogs having low serum T4 concentration. Although 16 (38%) of the 42 dogs with hyperadrenocorticism had a high FT4 fraction, indicative of diminished serum T4 binding, normal FT4 concentration was found in only 6 of the 16 dogs (38%) with low total T4 values. Mean serum T3 concentration in dogs with hyperadrenocorticism (0.79 nmol/L) was also significantly (P < 0.001) lower than the normal value (1.16 nmol/L), with 39% of the dogs having T3 values below the normal range. Individual T3-to-T4 and T3-to-FT4 ratios, indices of T3 production and/or clearance, were above the normal range in 29 and 24% of dogs with hyperadrenocorticism, respectively. Mean reverse T3 concentration in dogs with hyperadrenocorticism (0.17 nmol/L) was also significantly (P < 0.001) lower than the normal mean value (0.39 nmol/L), with 48% of the dogs having reverse T3 values below the normal range. Of the 21 dogs in which all iodothyronines were measured, 6 (29%) had undetectable values for all hormones. Therefore, of dogs with hyperadrenocorticism, a subgroup had reduced serum T4 binding and another group had low values for all iodothyronines consistent with secondary hypothyroidism, but few dogs had low T3-to-FT4 ratio (indicative of inhibition of T4 to T3 conversion) commonly seen in human patients with Cushing's syndrome. The pattern of changes in dogs was reminiscent of the changes observed in rats with chronic glucocorticoid excess, in which pituitary thyrotropin secretion is suppressed and T3 production and degradation are depressed. Despite the severity of the changes in FT4 concentration in some dogs, it is possible that overt hypothyroidism is averted by maintenance of serum T3 concentration.
Pharmacokinetics of metronidazole and its concentration in body fluids and endometrial tissues of mares
Authors: Specht T. E. , Brown Murray P. , Gronwall Ronald R. , Rib Wendy J. , Houston A. E.
Published: January 2024

Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single iv injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg.

Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal fluid, and urine. Metronidazole concentrations in csf and endometrial tissues were measured after the fourth maintenance dose. The highest mean concentration in serum was 13.9 ± 2.18 μg/ml at 40 minutes after the loading dose (time 0). The highest mean synovial and peritoneal fluid concentrations were 8.9 ± 1.31 μg/ml and 12.8 ± 3.21 μg/ml, respectively, 2 hours after the loading dose. The lowest mean trough concentration in urine was 32 μg/ml. Mean concentration of metronidazole in csf was 4.3 ± 2.51 μg/ml and the mean concentration in endometrial tissues was 0.9 ± 0.48 μg/g at 3 hours after the fourth maintenance dose.

Two mares hospitalized for treatment of bacterial pleuropneumonia were given metronidazole (15.0 mg/kg, po, initially then 7.5 mg/kg, po, q 6 h), while concurrently receiving gentamicin, potassium penicillin, and flunixin meglumine iv. Metronidazole pharmacokinetics and serum concentrations in the sick mares were similar to those obtained in the healthy mares.
Effect of hypertonic and isotonic saline solutions on plasma constituents of conscious horses
Authors: Bertone Joseph J. , Shoemaker Katherine E.
Published: January 2024

Blood constituents and vascular volume indices were determined in 5 standing horses by use of 2-period crossover experimental design. Horses were either administered hypertonic (2,400 mosm/kg of body weight, iv) or isotonic (300 mosm/kg, iv) saline solution. Each solution was administered at a dosage of 5 ml/kg (infusion rate, 80 ml/min). Samples for determination of pcv, plasma volume, blood volume, plasma osmolality, total amount of plasma protein and plasma concentrations of protein, Na, K, and Cl were collected at 0 hour (baseline, before fluid infusion) and 0.5 hour (at the end of fluid infusion), and subsequently, at 0.25- or 0.5-hour intervals for 4.5 hours. All horses were given the predetermined dose of fluids by 0.5 hour after beginning the saline infusion. Values of P ≤ 0.05 were considered significant.

Administration of hypertonic saline solution was associated with decreased mean body weight by 4.5 hours, but weight change after isotonic saline administration was not significant. Other than body weight and plasma protein concentration, between-trial difference (treatment effect) was not observed for any measured variable or index. The F values indicated that increasing the number of horses would have not changed these results. A time effect was evident across both trials, so that mean (±sd) plasma volume increased (12.3 ± 1.07%) and mean plasma protein concentration (−12.1 ± 1.03%) and pcv (−11.9 + 0.67%) decreased proportionately and transiently in association with administration of either fluid at that volume. Other time effects included increased plasma osmolality and Na and Cl concentrations. Blood volume estimates and total amount of plasma protein remained unchanged. These data indicate that in conscious clinically normal horses, changes in plasma protein concentration reflect changes in plasma volume and that blood volume may be regulated by alterations in plasma volume and red cell mass. These data also indicate that changes in plasma volume and constituent concentrations may be similar in response to administration of either 0.9% (300 mosm/kg) or 7.2% (2,400 mosm/kg) NaCl solutions (5 ml/kg) and that clinically normal horses can rapidly regulate variable Na loads.
Bronchoscopy of the horse
Authors: Sweeney Corinne Raphel , Weiher Janice , Baez Jennifer L. , Lindborg Susan R.
Published: January 2024

The endobronchial anatomy of 12 lung specimens from horses and 12 healthy, standing, sedated horses was evaluated, using a 200-cm-long, 9.5-mm-diameter videoendoscope. On the basis of these findings, the nomenclature system of Amis and McKiernan was modified for identification of airways of horses during bronchoscopy. Lobar bronchi are identified on the basis of the side of the bronchial tree on which they were found and the order in which they originated from the primary bronchus. Thus, RB1, RB2, and RB3 referred to right cranial lobar bronchus, respectively. On the left side, the designation of LB1 and LB2 refer to the left cranial lobar bronchus and the left caudal lobar bronchus, respectively. Segmental bronchi are identified by consecutive numbers in the order of origination from the lobar bronchus. The direction of the segmental bronchus was denoted by the capital letter D (dorsal), V (ventral), L (lateral), M (medial), R (rostral), and C (caudal). Subsegmental bronchi were identified in the order of origination from the segmental bronchi, using lower case letters (eg, RB2, 1V, a or RB2, 1V, aV). For subsequent branching of the subsegmental bronchi, the branches were numbered consecutively by their order of origination (eg, RB2, 1V, aV, 1D).
Immunotoxicity of ochratoxin A to growing gilts
Authors: Harvey Roger B. , Elissalde Marcel H. , Kubena Leon F. , Weaver Elizabeth A. , Carrier Donald E. , Clement Beverly A.
Published: January 2024

Ochratoxin A (oa) was incorporated in the diets of growing gilts (mean body weight, 20.1 kg) at a concentration of 2.5 mg of oa/kg of feed and was fed continuously for 35 days. Humoral and cell-mediated immunologic measurements were evaluated to determine the effects of oa on immune function in swine. Cutaneous basophil hypersensitivity to phytohemagglutinin (pha), delayed hypersensitivity to tuberculin, pha-induced lymphocyte blastogenesis, interleukin-2 production, total and isotype immunoglobulin concentrations, antibody response to chicken rbc, and macrophage activation were used to evaluate immune function. Gilts treated with oa had reduced cutaneous basophil hypersensitivity response to pha, reduced delayed hypersensitivity to tuberculin, decreased stimulation index for lymphoblastogenesis, decreased interleukin-2 production when lymphocytes were stimulated with concanavalin A, and decreased number and phagocytic activity of macrophages. Differences were not observed for total and isotype immunoglobulin concentrations, or humoral hemagglutination (chicken rbc) titer. These data indicate that oa may suppress cell-mediated immune response in growing swine.
Physiologic effects of administration of interleukin 1β in cows
Authors: Goff Jesse P. , Naito Yoshihisa , Kehrli Marcus E. , Hayes Phillip , Daley Michael
Published: January 2024

The immunomodulating polypeptide interleukin 1β (il-1β) has been shown to be homologous to osteoclast-activating factor and is capable of stimulating increased osteoclastic bone resorption. This effect prompted an investigation into the potential use of il-1β for prevention of parturient paresis, a disease of dairy cows characterized by hypocalcemia and poor osteoclastic resorption of bone. Six nonpregnant cows were treated with a high dosage of il-1β (166 ng/kg of body weight) every 8 hours for 4 days. The il-1β treatment significantly (P < 0.05) increased urinary hydroxyproline excretion, an index of osteoclast activity, indicating that bone calcium resorption might be stimulated by il-1β treatment of cows. However, il-1β treatment also caused transient fever, inappetence, increased pulse and respiratory rate, and diuresis. The acute, but transient, effect of il-1β treatment was to cause a decrease in plasma calcium and phosphorus concentrations. The pleiotropic effects of il-1β administration negated the positive effects on osteoclastic bone resorption, and indicates that this cytokine may be of minimal benefit for prevention of parturient paresis.
Cross-reactivity between a monoclonal antibody that recognizes a tumor-associated antigen on bovine lymphosarcoma cells and blood lymphocytes from various mammalian species
Authors: Aida Yoko , Okada Kosuke , Kageyama Rena , Amanuma Hiroshi
Published: January 2024

Tumor-associated antigens that are expressed in lymphosarcoma B cells of cattle with enzootic bovine leukosis had been analyzed in terms of their reactivity with 13 monoclonal antibodies (mab). By use of flow cytometry and radioimmunoprecipitation, 1 of the mab (c143) that recognized a tumor-associated antigen cross-reacted with blood lymphocytes (bl) from various mammalian species. By use of flow cytometry, the c143 mab reacted with 10 to 49% of bl derived from human beings, mice, dogs, horses, pigs, llamas, sheep, goats, and cattle. Titer of the c143 mab with bl from horses, pigs, human beings, and llamas ranged between 1:6.0 × 104 and 1:5.3 × 105; titer associated with bl of goats and sheep was 1:1.6 × 106; and that associated with bl of cattle was 1:4.3 × 107. The c143 mab specifically immunoprecipitated 3 homologous proteins from cell extracts of caprine, ovine, and bovine bl (32-, 34-, and 36- to 37-kDa bovine proteins; 31-, 32-, and 36- to 37-kDa caprine proteins; and 31.5-, 33-, and 36- to 37-kDa ovine proteins), but none was immunoprecipitated from human, murine, canine, porcine, and llama bl. These results indicate that the avidity of the c143 mab in binding to bl from ruminants (eg, goats, sheep, and cattle) is higher than that to bl from human beings, mice, dogs, horses, pigs, and llamas. In sheep, the c143 mab could immunoprecipitate the aforementioned proteins from bl of the Suffolk breed, but not bl from the Corriedale breed, whereas the c143 mab immunoprecipitated apparently identical proteins from bl of 4 breeds of cattle.
Evaluation of a modified-live virus vaccine administered in ovo to protect chickens against Newcastle disease
Authors: Ahmad Jamil , Sharma Jagdev M.
Published: January 2024

The B1 strain of Newcastle disease virus (ndv-B1), which is nonpathogenic for newly hatched chickens, killed embryos when it was used to inoculate chicken eggs at embryonation day 18. Treatment of ndv-B1 with an alkylating agent, ethylmethane sulfonate (ems) markedly reduced the pathogenicity of the virus for 18-day-old chicken embryos. Eggs inoculated with the modified virus (ndv-B1-ems) hatched, and the virus was isolated from lungs and spleen of 1-day-old chickens. The hatched chickens developed antibody to ndv and were protected against challenge exposure (at 4 weeks of age) with a highly virulent GB-Texas strain of ndv. Presence of maternal antibody to ndv in embryonating eggs did not influence the protective ability of ndv-B1-ems, which also induced protective immunity when administered to 4-week-old chickens. The 50% protective dose of ndv-B1-ems in maternal antibody-negative and -positive embryos was calculated to be 10.77 and 17.70 embryo 50% lethal doses, respectively. Results of the study indicated that ndv-B1-ems may be used as an embryo vaccine to protect chickens against Newcastle disease.
Arterial-venous difference in atrial natriuretic peptide concentration during exercise in horses
Authors: McKeever Kenneth H. , Hinchcliff Kenneth W. , Cooley Jodi L. , Lamb David R. , Muir William W.
Published: January 2024

Six nontrained mares were subjected to steady-state, submaximal treadmill exercise to examine the effect of exercise on the plasma concentration of atrial natriuretic peptide (anp) in arterial, compared with mixed venous, blood. Horses ran on a treadmill up a 6° grade for 20 minutes at a speed calculated to require a power equivalent to 80% of maximal oxygen uptake (Vo2MAX). Arterial and mixed venous blood samples were collected simultaneously from the carotid and pulmonary arteries of horses at rest and at 10 and 20 minutes of exercise. Plasma was stored at − 80 C and was later thawed; anp was extracted, and its concentration was determined by radioimmunoassay. Exercise caused significant (P < 0.05) increases in arterial and venous plasma anp concentrations. Mean ± sem arterial anp concentration increased from 25.2 ± 4.4 pg/ml at rest to 52.7 ± 5.2 pg/ml at 10 minutes of exercise and 62.5 ± 5.2 pg/ml at 20 minutes of exercise. Mean venous anp concentration increased from 24.8 ± 4.3 pg/ml at rest to 67.2 ± 14.5 pg/ml at 10 minutes of exercise and 65.3 ± 13.5 pg/ml at 20 minutes of exercise. Significant differences were not evident between arterial or mixed venous anp concentration at rest or during exercise, indicating that anp either is not metabolized in the lungs or is released from the left atrium at a rate matching that of pulmonary metabolism.
Regulation of matrix metabolism in equine cartilage explant cultures by interleukin 1
Authors: MacDonald Melinda H. , Stover Susan M. , Willits Neil H. , Benton Hilary P.
Published: January 2024

Explant cultures were set up, using articular cartilage obtained from metatarsophalangeal joints of 11 horses. Explants from 2 horses were used to determine culture conditions appropriate for tissue viability. The cartilage explants maintained steady-state metabolism of proteoglycans during a 13-day evaluation period. The metabolic response of equine articular cartilage to incubation with recombinant human interleukin 1 (0.01 to 100 ng/ml) was studied, using cartilage obtained from the remaining 9 horses, age of which ranged from 3 months to 20 years. Interleukin 1 induced a dose-dependent release of glycosaminoglycan from the matrix during a 3-day incubation period. It also caused dose-dependent inhibition of glycosaminoglycan synthesis during a 3-hour pulse-labeling period. Expiants obtained from older horses were significantly (P < 0.05) less responsive to interleukin 1, with respect to synthesis and release of glycosaminoglycan.
Effects of chlorothiazide on urinary excretion of calcium in clinically normal dogs
Authors: Lulich Jody P. , Osborne Carl A.
Published: January 2024

Administration of thiazide diuretics has been recommended to prevent calcium oxalate urolith development in dogs. To evaluate the effects of thiazide diuretics in dogs, 24-hour urine excretion of calcium was measured in 6 clinically normal Beagles after administration of chlorothiazide (ctz) for 2 weeks, administration of ctz for 10 weeks, and administration of calcium carbonate and ctz for 2 weeks. Compared with baseline values, 24-hour urine calcium excretion did not decrease after ctz administration. When ctz was given at a high dosage (130 mg/ kg of body weight), urinary calcium excretion was significantly (P < 0.04) higher than baseline values. Based on these observations, we do not recommend ctz for treatment or prevention of canine calcium oxalate urolithiasis.
Effect of short-term exposure of chickens to corticosterone on resistance to challenge exposure with Escherichia coli and antibody response to sheep erythrocytes
Authors: Gross W.B.
Published: January 2024

Chickens in a low-stress environment (heterophil/lymohocyte ratio 0.31) were given feed containing 30, 40, or 60 mg of corticosterone/kg of feed for 0.5 hour. Between 0.5 to 12 hours later, chickens were exposed to Escherichia coli via the air sac route. For each dose of corticosterone, there was an untreated control group that was exposed to E coli via the air sac route. The prevalence of pericarditis was reduced from 78 to 7% between 2 and 4 hours after exposure. Resistance was associated with heterophil/lymphocyte (h/l) ratios greater than 1.04. Peak h/l ratios correlated positively with amount of corticosterone in the feed.

In one experiment, chickens were inoculated iv with sheep erythrocytes at various times after consumption of feed containing corticosterone. Suppression of antibody responsiveness was most pronounced 4 hours later. Antibody responsiveness correlated positively with lymphocyte numbers.

Histologic examination of air sacs was made following euthanasia at various times after E coli exposure. Lesions observed in control chickens included: edema at 0.5 hour, beginning of heterophil infiltration at 1 hour, increased edema and heterophil infiltration at 2 hours, and severe edema and heterophil infiltration at 4 hours. Lesions were not observed in chickens that had been given feed containing 40 mg of corticosterone/kg of feed.
Double-antibody sandwich enzyme-linked immunosorbent assay and immunoblot analysis used for control of caseous lymphadenitis in goats and sheep
Authors: ter Laak E. A. , Bosch J. , Bijl G. C. , Schreuder B. E. C.
Published: January 2024

A double-antibody sandwich elisa for detection of antibodies directed against the exotoxin of Corynebacterium pseudotuberculosis, the cause of caseous lymphadenitis (CL) in small ruminants, was developed. A concentrated exotoxin was used. For interpretation of elisa results, these sera were tested: sequentially obtained sera of C pseudotuberculosis-inoculated goats and sheep that were monitored for 68 weeks; sequentially obtained sera from 80 goats of 3 flocks with CL; sera from 652 goats of 7 flocks without CL; sera from 160 sheep of 4 flocks without CL; and 2,265 caprine and 208 ovine sera submitted for diagnostic testing. Data regarding the infection status and history of 10,454 of the 23,302 animals were collected after testing; most of these were goats that had been part of a CL control program. Specificity and sensitivity of the elisa were nearly 100%. Subsequently, 31,978 animals from which no data on infection status of flocks had been collected were then tested. It was concluded that the elisa is a useful diagnostic test for CL eradication programs. Sera with doubtful or inconclusive elisa results were examined by use of immunoblot analysis. Proteins from C pseudotuberculosis culture supernatant were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nitrocellulose. Six proteins with molecular mass of 68, 65, 39, 38, 31, and 29 kDa reacted with sera from goats and sheep with experimentally induced or naturally acquired infection. Immunoblot analysis was valuable in classifying sera with doubtful or inconclusive results by elisa.
Urethral pressure response to α-adrenergic agonist and antagonist drugs in anesthetized healthy male cats
Authors: Frenier Susan L. , Knowlen Grant G. , Speth Robert C. , Moore Michael P.
Published: January 2024

Urethral smooth muscle tone in response to treatment with phenylephrine, a selective α1-adrenergic receptor agonist, and prazosin a selective α1-adrenergic receptor antagonist, was evaluated in 12 anesthetized healthy adult sexually intact male cats. Intravenous administration of prazosin (20 to 30 μg/kg of body weight) decreased the average preprostatic and prostatic intraurethral pressure, compared with baseline and postphenylephrine (20 to 30 μg/kg) administration, values. Neither prazosin nor phenylephrine administration had an effect on functional urethral length. Results have implications for the pharmacologic management of lower urinary tract disorders in male cats.
Histomorphometric analysis of the rumen of sheep during development
Authors: Franco A. , Regodón S. , Robina A. , Redondo E.
Published: January 2024

Histomorphometric and scanning electron microscopic analyses were carried out on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histodifferentiation of the rumen took place at 33 days of fetal life. Ruminal pillars were observed at 42 days, and at 61 days, ruminal papillae appeared as evaginations of the epithelial stratum basale. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life; thereafter, numbers decreased gradually and subsequently stabilized in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Age and diet were recognized as factors that determine the structure of the ruminal mucosa. Growth curves and formulas were set out for each tissue layer.
Effects of orally administered prednisone on glucose tolerance and insulin secretion in clinically normal dogs
Authors: Moore George E. , Hoenig Margarethe
Published: January 2024

Prednisone was administered orally for 4 weeks at a dosage of 1.1 mg/kg of body weight/d, in divided dose every 12 hours, to a group of healthy adult dogs (n = 12). Intravenous glucose tolerance testing was performed before and after the 28-day regimen in each dog, as well as in dogs of a control group (n = 6). Glucose metabolism was evaluated by measurement of preprandial plasma insulin and glucose concentrations, total insulin secretion, and fractional clearance of glucose.

Mean preprandial plasma insulin and glucose concentrations were not increased after the 4-week regimen of prednisone. Total insulin secretion in response to an IV administered glucose load was not increased in treated dogs, compared with pretreatment values or with values for control dogs. The fractional clearance of glucose was also not altered in dogs given prednisone. Results indicate that anti-inflammatory doses of prednisone, given orally for 4 weeks, probably do not alter insulin sensitivity or glucose tolerance in clinically normal dogs.
Pulmonary response to intravenous administration of 5-hydroxytryptamine after type-2 receptor blockade in healthy calves
Authors: Linden Annick S. , Desmecht Daniel J.-M. , Amory Hélène , Rollin Frédéric A. , Michaux Charles L. , Lekeux Pierre
Published: January 2024

The purpose of this study was to investigate the mechanism by which 5-hydroxytryptamine (5-ht) modifies respiratory function, specifically, hyperventilation, diffuse bronchoconstriction, and pulmonary arterial hypertension in cattle. We determined whether the IV response to 5-ht in calves was attributable to stimulation of 5-ht2 receptors.

Six healthy unsedated young bull calves of the Friesian (n = 4) and of the Belgian White and Blue (n = 2) breeds were used. A specific 5-ht2 antagonist (metrenperone, 0.05 mg/kg of body weight) was administered IM 30 minutes before the cattle were given a 5-minute IV 5-ht infusion. Pulmonary function values were registered before, during, and after the 5-ht challenge infusion. Minute volume increased significantly, because of an increase in respiratory rate. Conversely, lung dynamic compliance, total pulmonary resistance, and pulmonary arterial pressure were not changed.

We concluded that in cattle, 5-ht-induced ventilatory response is not mediated through activation of 5-ht2 receptors. However, the 5-ht2 receptors are involved in 5-ht-induced broncho- and pulmonary vasoconstriction.
Serum triiodothyronine, total thyroxine, and free thyroxine concentrations in horses
Authors: Sojka Janice E. , Johnson M. A. , Bottoms G. D.
Published: January 2024

The objectives of this experiment were to determine serum concentrations of triiodothyronine (T3), thyroxine (T4), and free thyroxine (fT4) at rest, following thyroid-stimulating hormone (tsh) administration, and following phenylbutazone administration in healthy horses. This was done to determine which available laboratory test can best be used for diagnosis of hypothyroid conditions in horses. Serum T3, T4, and fT4 concentrations in serum samples obtained before and after tsh stimulation and following phenylbutazone administration for 7 days were determined.

Baseline values ranged from 0.21 to 0.80 ng of T3/ml, 6.2 to 25.1 ng of T4/ml, and 0.07 to 0.47 ng of fT3/dl. After 5 IU of tsh was administered IV, serum T3 values increased to 6 times baseline values in 2 hours. Thyroxine values increased to 3 times baseline values at 4 hours and remained high at 6 hours. Free T4 values increased to 4 times baseline values at 4 hours and remained high at 6 hours. Administration of 4.4 mg of phenylbutazone/kg, every 12 hours for 7 days significantly decreased T4 and fT4 values, but did not significantly affect serum T3 concentrations. It was concluded that a tsh stimulation test should be performed when hypothyroidism is suspected. Measurement of serum fT4 concentrations, by the single-stage radioimmunoassay, does not provide any additional information about thyroid gland function over that gained by measuring T4 concentrations. Phenylbutazone given at a dosage of 4.4 mg/kg every 24 hours, for 7 days did significantly decrease resting T4 and fT4 concentrations, but did not significantly affect T3 concentrations in horses.
Clinical pathologic profiles of dogs and turkeys with congestive heart failure, either noninduced or induced by rapid ventricular pacing, and turkeys with furazolidone toxicosis
Authors: O'Brien Peter James , O'Grady Michael , Lumsden John H. , Holmberg David L. , Shen Hua , Weiler Janice E. , Horn Rhonnie D. , Mirsalimi S. Mehdi , Julian Richard J.
Published: January 2024

Characteristic alterations in the serum and urine biochemical profiles of Doberman Pinschers with congestive heart failure (chf) resulting from idiopathic dilated cardiomyopathy were determined. We compared these alterations with those observed in 2 other models of chf: rate overload induced by rapid ventricular pacing in dogs, and biventricular hypertrophy and dilatation induced in turkey poults by furazolidone toxicosis. Serum and urine biochemical changes in both models of chf in dogs were mild to moderate in degree, and were moderately consistent. They could be attributed to secondary neurohumoral, hepatic, and renal effects of heart failure. The most marked and consistent changes observed were mildly decreased anion gap that developed, in part, because of decreased serum sodium concentration, moderately increased catecholamine concentrations, moderate lactaciduria, hyposthenuria, and mildly increased urea concentrations and liver enzyme activities. In birds with furazolidone cardiomyopathy, we observed mild increases in serum urate concentration, liver and muscle enzyme activities, but moderately increased sodium concentration with decreased chloride concentration. In the pacing and furazolidone models, in which chf was rapidly induced, moderate to marked hypoproteinemia was attributable to decreases in albumin and globulin concentrations. Using the avian model we found that the hypoproteinemia could be largely attributed to blood volume expansion, and to a lesser extent, inanition. Development of hypoalbuminemia during rapid ventricular pacing and furazolidone treatment may contribute to the effects of rate overload or drug toxicity in the pathogenesis of chf, because hypoalbuminemia may contribute to altered hemodynamics and neuroendocrine system activation. Our data indicate that clinical biochemical analysis of serum and urine may be useful for assessing progression of chf.
Temporal matrix synthesis and histologic features of a chondrocyte-laden porous collagen cartilage analogue
Authors: Nixon Alan J. , Sams Andrew E. , Lust George , Grande Daniel , Mohammed Hussni O.
Published: January 2024

Cartilage resurfacing by chondrocyte transplantation, using porous collagen matrices as a vehicle to secure the cells in cartilage defects, has been used experimentally in animals. This in vitro study evaluated the temporal morphologic features and proteoglycan synthesis of chondrocyte-laden collagen matrices. Forty-two porous collagen disks were implanted with a minimum of 6 × 106 viable chondrocytes, covered by a polymerized collagen gel layer, and 6 disks were harvested after 0, 3, 7, 10, 14, 18, or 22 days of incubation in supplemented Ham's F12 medium at 37 C and 5% CO2. Histologic and histo-chemical evaluation of formalin-fixed segments of the cultured disks indicated that the chondrocytes proliferated in the implant, producing small groups and linear segments of cells by day 14. The collagen framework remained intact over the course of the study with thick areas attributable to depositions of matrix material after day 10. Alcian blue-stained matrix was evident in the pericellular region of chondrocytes in sections of disks harvested on days 14, 18, and 22.

Glycosaminoglycan (GAG) assay by dimethyl-methylene blue dye binding after papain digestion of the disk segments revealed negligible amounts of GAG at day 0. Significant (P ≤ 0.0001) increase in total GAG content was observed by day 3 (0.329 M-μg of disk) and further increases were observed until a plateau in GAG quantity was seen on day 14. Mean peak GAG content was 0.553 ± 0.062 μg/mg. Secondary treatment of the papain-digested implants with keratanase and chondroitinase ABC yielded similar trends in chondroitin sulfate (CS) and keratan sulfate (KS) concentrations. The CS content significantly (P = 0.0002) increased for the first 14 days of incubation, then a plateau was observed for the remainder of the study. Peak CS content was 0354 ± 0.037 μg/mg. Concentration of KS reached a plateau earlier than did CS content, with peak amount of 0.193 ± 0.027 μg/mg on day 10. Fluctuations in K5 content were not significant until an increase on day 22.

Chondrocytes actively populated the collagen implants, increasing in number and synthesizing matrix GAG epitopes over the 22 days of incubation. These results indicate that chondrocyte-laden porous collagen matrices may be suitable cartilage analogue materials and the optimal metabolic time for transfer to cartilage defects is 10 to 14 days.
Blockade of endotoxin-induced cecal hypoperfusion and ileus with an α2 antagonist in horses
Authors: Eades Susan C. , Moore James N.
Published: January 2024

Stimulation of α2 adrenergic receptors inhibits colonic motility and may constrict some peripheral vascular beds. Endotoxemia elicits release of sympathetic neurotransmitters and increases sympathetic nerve activity, which may result in stimulation of α2 adrenergic receptors. The objective of this study was to determine whether blockade of α2 adrenergic receptors would restore cecal motility and blood flow during endotoxemia in horses. Strain-gauge force transducers and ultrasonic flow probes were used to measure cecal and colonic mechanical activity and lateral cecal arterial blood flow. Intravenous infusion of endotoxin (cumulative dose of 0.03 mg/kg) significantly decreased cecal and right ventral colon contractile activity and lateral cecal arterial blood flow. Slow iv infusion of yohimbine (cumulative dose of 75 μg/kg) significantly attenuated those effects of endotoxin. On the basis of our findings, we concluded that endotoxemia causes cecal and proximal colonic ileus and cecal hypoperfusion via a mechanism that involves α2 adrenergic receptors.
Contributions to variance in force-plate analysis of gait in dogs
Authors: Jevens D. J. , Hauptman J. G. , DeCamp C. E. , Budsberg S. C. , Soutas-Little R. W.
Published: January 2024

Coefficients of variation were calculated for peak vertical force and for vertical, cranial, and caudal impulses recorded from the left forelimb and left hind limb of 5 dogs that were trotted across a force plate 5 times by 5 handlers. To determine the percentages of variance attributable to dogs, handlers, and trial repetitions, data recorded for each force measurement were analyzed according to a two-factor anova. Coefficients of variation for peak vertical forces and for vertical impulses varied between 5.8 and 8.5%. Coefficients of variation for the forelimb cranial and caudal impulses and for the hind limb cranial and caudal impulses were 26.4 and 30.5%, and 63.0 and 25.9%, respectively. The percentage of the total variance attributable to dogs and to trial repetitions ranged from 14 to 69% and from 29 to 85%, respectively, depending on the force or impulse evaluated. The percentage of variance attributable to handlers varied between 0 and 7%. The trivial amount of variation attributable to handlers indicated that multiple handlers may be used in experiments without an appreciable influence on the results.