bluuebunny/crossref_metadata_2025 huggingface dataset:
Urine-blood carbon dioxide tension gradient in healthy dogs
Authors: Shaw Darcy H.
Published: January 2024

The urine-blood carbon dioxide tension (Pco2) gradient was measured in 10 healthy mature Beagles after alkalinization of the urine by administration of sodium bicarbonate. The mean (± sd) urine-blood Pco2 gradient was 65.92 ± 14.42 mm of Hg, with range of 38.2 to 82.2 mm of Hg. Mean urine Pco2 was 110.21 ± 14.19 mm of Hg, with range of 84.1 to 127.3 mm of Hg. Because urine-blood Pco2 gradient < 30.0 mm of Hg or urine Pco2 < 55 mm of Hg in people is diagnostic for a defect in distal nephron acidification, similar values might be applicable to diseases in dogs.
Evaluation of progesterone deficiency as a cause of fetal death in mares with experimentally induced endotoxemia
Authors: Daels Peter F. , Stabenfeldt George H. , Hughes John P. , Odensvik Kristina , Kindahl Hans
Published: January 2024

The role of decreased luteal activity in embryonic loss after induced endotoxemia was studied in mares 21 to 35 days pregnant. Fourteen pregnant mares were treated daily with 44 mg of altrenogest to compensate for the loss of endogenous progesterone secretion caused by prostaglandin F2α (pgf2α) synthesis and release following intravenous administration of Salmonella typhimurium endotoxin. Altrenogest was administered daily from the day of endotoxin injection until day 40 of gestation (group 1; n = 7), until day 70 (group 2; n = 5), or until day 50 (group 3; n = 2).

In all mares, secretion of pgf2α, as determined by the plasma 15-keto-13,14-dihydro-pgf2α concentrations, followed a biphasic pattern, with an initial peak at 30 minutes followed by a second, larger peak at 105 minutes after endotoxin injection. Plasma progesterone concentrations decreased in all mares to values < 1 ng/ml within 24 hours after endotoxin injection.

In group 1, progesterone concentrations for all mares were < 1 ng/ml until the final day of altrenogest treatment. In 6 of 7 mares in group 1, the fetuses died within 4 days after the end of treatment, with progesterone concentrations < than 1 ng/ml at that time. In the mare that remained pregnant after the end of treatment, plasma progesterone concentration was 1.6 ng/ml on day 41 and increased to 4.4 ng/ml on day 44.

In group 2, all mares remained pregnant, even though plasma progesterone concentrations were < 1 ng/ml in 4 of 5 mares from the day after endotoxin injection until after the end of altrenogest treatment. One group-2 mare appeared to develop a secondary corpus luteum before day 70, with progesterone concentrations greater than 1 ng/ml from day 36 through day 70.

Daily altrenogest administration consistently prevented pregnancy loss, which usually follows induced endotoxemia. Altrenogest administration offers a reliable and practical treatment for the prevention of fetal loss following endotoxemia in mares < 2 months pregnant.

One group-3 mare remained pregnant, and in the other mare, fetal death was diagnosed 8 days after endotoxin administration, although this mare was still being treated with altrenogest. In that case fetal death was believed to be unrelated to the treatment.
Effects of topical administration of 2.0% pilocarpine on intraocular pressure and pupil size in cats
Authors: Wilkie David A. , Latimer Claire A.
Published: January 2024

Effects of topical administration of a single dose of 2% pilocarpine on intraocular pressure (iop) and pupil diameter were evaluated in normotensive eyes of 10 clinically normal cats over 12 hours. Mean (± sem) normal iop was 17.1 (± 1.1) mm of Hg and, diurnal fluctuation was observed, with the highest iop seen in the evening. Mean ( ± sem) normal pupil diameter was found to be 10.1 (± 0.5) mm. Topical treatment with pilocarpine resulted in reduction of iop in treated and nontreated eyes. This effect was time-dependent and was first observed at 4 hours after treatment. Mean reduction of iop was 15.2% in the treated eye and 9.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction in pupil diameter was 28.5% in the treated eye and 14.2% in the nontreated eye.

Topically administered pilocarpine results in reduction of iop and pupil diameter in treated and contalateral eyes, which supports the use of pilocarpine for treatment of glaucoma in cats.
Ototoxic potential of gentamicin in ponies
Authors: Nostrandt Amy C. , Pedersoli Waldir M. , Marshall A. Edward , Ravis William R. , Robertson Benjamin T.
Published: January 2024

Ototoxicosis was evaluated in 6 healthy ponies given 5 mg of gentamicin/kg of body weight, q 8 h, im. Ponies 1, 2, and 3 were dosed for 7 days and ponies 4, 5, and 6 were dosed for 14 days. Serum peak and trough concentrations of gentamicin were measured by radioimmunoassay at regular intervals. Brain stem auditory-evoked responses were recorded every 5 days up to 60 days after the first dose to monitor auditory function. Although serum gentamicin concentrations were within or above the accepted clinical therapeutic range, loss of auditory function was not observed at the frequency range (1 to 4 kHz) tested. Serum chemical values remained within the accepted clinical range and no evidence of nephrotoxicosis was observed. Seemingly, gentamicin given im to healthy ponies was safe and had minimal risk of side effects.
Effect of dietary α-linolenic acid on endotoxin-induced production of tumor necrosis factor by peritoneal macrophages in horses
Authors: Morris Debra Deem , Henry Michelle M. , Moore James N. , Fischer J. Kay
Published: January 2024

A study was conducted to determine whether dietary supplements with α-linolenic acid altered the ability of equine peritoneal macrophages to produce tumor necrosis factor (tnf) in response to endotoxin. Peritoneal macrophages were harvested from 6 healthy adult horses before and after the horses were fed a nutritionally balanced ration that contained 8% linseed oil as a source of α-linolenic acid. The macrophages were cultured in media containing no additives (control), endotoxin (0.5 to 50 ng/ml), or the calcium ionophore, A23187. Macrophage supernatants were collected after 6 and 24 hours’ incubation and stored at −70 C. Tumor necrosis factor activity was estimated by a modified in vitro cytotoxicity bioassay, using the murine fibrosarcoma cell line, WEHI 164 clone 13. The tnf activity after 6 and 24 hours’ incubation was greater in culture media of macrophages exposed to endotoxin than in media from control macrophages. For macrophages cultured in media that contained endotoxin, neither the concentration of endotoxin nor incubation time had any effect on tnf activity. Endotoxin-induced macrophage production of tnf, as determined by measurement of tnf activity, was significantly less after horses were fed the α-linolenic acid-rich ration for 8 weeks.
Effect of administration of phenylbutazone or progesterone on recovery of embryos from the uterus of mares 5 days after ovulation
Authors: Hinrichs Katrin , Watson Elaine D.
Published: January 2024

Twelve horse mares were used to investigate the effect of phenylbutazone or progesterone administration on uterine tubal motility, as reflected by embryo recovery from the uterus on day 5 after ovulation. Four treatment groups were used: group A (controls), in which uterine flush was performed 7 to 11 days after ovulation; group B (5-day controls), in which uterine flush was performed 5 days after ovulation; group C, in which uterine flush was performed 5 days after ovulation following administration of phenylbutazone (2 g, iv) on day 3; and group D, in which uterine flush was performed 5 days after ovulation following administration of progesterone in oil (250 mg, im) on days 0, 1, and 2. Each mare was randomly assigned to each group once. Embryo recovery for each group was: group A, 13 embryos from 12 mares; group B, 3 embryos from 12 mares; group C, 4 embryos from 11 mares; and group D, 1 embryo from 11 mares. Recovery of embryos on day 5 in 3 of 12 nontreated mares indicated that equine embryos may enter the uterus before day 6. Neither treatment increased embryo recovery from the uterus on day 5 over that from the uterus of the 5-day controls.
Evaluation of intravenous administration of concentrated immunoglobulin G to colostrum-deprived foals
Authors: Liu Irwin K. M. , Brown Christopher , Myers Robert C. , Hao Yu Lee
Published: January 2024

Ten foals of various breeds were deprived of colostrum from birth to 36 hours of age, then were allotted to 2 groups. Foals of group 1 (n = 6) were given 20 g (200 ml) of purified equine IgG iv in a 10% solution, and foals of group 2 (n = 4) were given 30 g (300 ml) of the same preparation. Total administration time for each 10 g of IgG in 100 ml was approximately 10 minutes. Serum IgG concentration in foals was assessed prior to, between 24 and 48 hours, and at 7 and 14 days after IgG administration.

Between 24 and 48 hours after IgG administration, mean serum IgG concentration in group-1 foals was 425 mg/dl (range, 350 to 480 mg/dl). Mean body weight for this group of foals was 50.3 kg (range, 43.3 to 54.7 kg).

For group-2 foals, mean serum IgG concentration was 768 mg/dl (range, 640 to 920 mg/dl) between 24 and 48 hours after administration of IgG. Foals of this group had mean body weight of 43.2 kg (range, 36.5 to 47.5 kg). Serum IgG concentration in group-2 foals at 24 to 48 hours was significantly (P = 0.005) greater than that in group- 1 foals.

Mean total IgG recovery at 24 to 48 hours, calculated on the basis of 94.5 ml of plasma volume/kg of body weight, was approximately 100%.

Values of IgG measured in all foals 1 and 2 weeks after administration of the IgG concentrate were equivalent to values expected after normal decay of passively acquired IgG. Mild, adverse reactions occurred in 3 of the 10 foals treated (1 group-1 foal and 2 group-2 foals).
Identity of Bacteroides isolates and previously named Bacteroides spp in clinical specimens of animal origin
Authors: Jang Spencer S. , Hirsh Dwight C.
Published: January 2024

During the years 1984 through 1987, 2,574 isolates of obligately anaerobic bacteria were isolated from samples submitted for analysis. The most common anaerobic isolates were members of the genus Bacteroides, representing 44.6% of the isolates. Of these, the most commonly isolated identifiable microorganisms were bile-resistant and nonpigmented, belonging to the B fragilis group of Bacteroides. Importantly, obvious predilections for any one species or group of Bacteroides were not apparent for animal or site (condition), except that the proportion of isolates belonging to the nonpigmented, bile-resistant group obtained from the respiratory tract was significantly (P < 0.005) higher than that not belonging to this group. On the other hand, the proportion of isolates of the nonpigmented, bile-resistant group obtained from abscesses was significantly lower than that not belonging to this group.
Acute hemolytic anemia induced by oral administration of indole in ponies
Authors: Paradis Mary Rose , Breeze R. G. , Laegreid W. W. , Bayly W. M. , Counts D. F.
Published: January 2024

Eight ponies were allotted to 2 groups of 4. Group-1 ponies (1-4) were given 0.2 g of indole/kg of body weight orally and group-2 ponies (5 to 8) were given 0.1 g of indole/kg. Various physical, hematologic, and physiologic measurements were obtained after administration of indole.

Intravascular hemolysis and hemoglobinuria were detected in both groups within 24 hours of dosing. Hemolysis was reflected by decreases in pcv, hemoglobin concentration, and rbc count, and an increase in indirect bilirubin. Erythrocyte fragility appeared to increase in both groups at 8 hours after dosing and peaked at 16 hours after dosing. At 72 hours after dosing, the rbc fragility value was less than predose measurements. Heinz body formation was noticed in group-2 ponies, but not in group 1.

Plasma indole concentrations increased in both groups from the nondetectable predose concentrations. Group-1 values were 203% of group-2 values. In group 2, plasma indole was nondetectable by 12 hours, whereas low concentrations could still be measured in the group-1 ponies at 24 hours.

Ponies in group 1 died or were euthanatized between 24 and 72 hours after dosing, whereas group-2 ponies were euthanatized between 48 and 120 hours. At necropsy, all body fat, mucous membranes, and elastic tissue were stained yellow. Hemoglobinuric nephrosis was the most prominent microscopic lesion.

Results of this study indicated that indole, a metabolite of the amino acid tryptophan, causes acute intravascular hemolysis in ponies.
Effects of gamma radiation and azathioprine on Brucella abortus infection in BALB/c mice
Authors: Elzer Philip H. , Rowe Gail E. , Enright Fred M. , Winter Alexander J.
Published: January 2024

Sublethal irradiation of BALB/c mice 4 hours prior to inoculation with 5 × 104 virulent Brucella abortus, caused significant (P < 0.01) reductions in bacterial numbers in comparison with numbers in unirradiated controls. Numbers of brucellae in the spleen were significantly lower by 5 days after inoculation and decreased thereafter, so that at 2 and 3 weeks after inoculation, there were up to 1,000-fold fewer organisms in the spleen of irradiated mice. The number of brucellae in the spleen increased in irradiated mice thereafter. The course of events in the liver was similar, but developed more slowly, and peak differences in bacterial numbers were about 1 log less. These phenomena were not attributable to differences in implantation of brucellae in the liver or spleen, nor to an abnormal distribution of organisms in other organs of irradiated mice. Irradiation of mice during the plateau phase of infection also resulted in significant (P < 0.05) reductions in bacterial counts in the spleen during the succeeding 4 weeks. Macrophage activation in the spleen, measured by a Listeria monocytogenes-killing assay, was significantly (P < 0.01) increased by irradiation alone at 1 week after inoculation and at that time was significantly (P < 0.01) greater in B abortus -infected, irradiated mice than in B abortus-infected controls. Histologic, cytologic, and immunologic studies revealed that the decrease in numbers of organisms between 1 and 2 weeks after inoculation in irradiated mice occurred at a time when their immune response to B abortus was suppressed and when numbers of neutrophils and monocytes infiltrating the spleen were significantly (P < 0.01) diminished. The increase in numbers of B abortus in organs of irradiated mice that began after the third week coincided with recovery of the immune response and an increase in numbers of neutrophils and monocytes in the infected organs. The course of B abortus infection was not substantially altered during the first 11 days after inoculation in mice infected at the height of a profound monocytopenia and neutropenia induced by azathioprine, a drug that by itself failed to activate macrophages. We hypothesized that, in irradiated mice, a rapid radiation-induced activation of resident macrophages to a brucellacidal state was coupled with an absence of newly formed monocytes in which virulent strains of B abortus could establish persistent infection, and that as susceptible monocytes emerged in mice recovering from the effects of irradiation, chronic infection became established.
Serologic detection and practical consequences of antigenic diversity among bovine viral diarrhea viruses in a vaccinated herd
Authors: Bolin Steven R. , Littledike E. Travis , Ridpath Julia F.
Published: January 2024

Samples of sera were obtained from 5,725 cows in a semiclosed herd. In each of the preceding 7 years, the herd was vaccinated against bovine viral diarrhea (bvd) with killed virus. Neutralizing antibody tests were done on all samples of sera, using cytopathic virus, bvd-tgac virus, that was antigenically distinct from the vaccine virus. Most samples of sera had high titers of neutralizing antibodies against bvd-tgac virus. In 48 samples of sera, neutralizing antibodies were not detected against bvdtgac virus, but were detected against the vaccine virus. Neutralizing antibodies against selected noncytopathic bvd viruses were not detected in several samples of serum that had neutralizing antibodies against the vaccine virus and bvd-tgac virus. Noncytopathic bvd virus was isolated from sera obtained from 3 cows < 4 years old. Two cows were available for further testing, and persistent infection with bvd virus was confirmed in both cows. The bvd viruses isolated from those cows were not neutralized by several samples of sera. Immunoprecipitation of polypeptides induced by the vaccine virus was done with selected samples of serum. Two patterns of immunoprecipitated viral-induced polypeptides were identified. One pattern was consistent with exposure of cows with live virus. The other pattern was consistent with exposure of cows with only the killed virus vaccine.
Transformation of Corynebacterium pseudotuberculosis by electroporation
Authors: Songer J. Glenn , Hilwig Ronald W. , Leeming Michael N. , landolo John J. , Libby Stephen J.
Published: January 2024

Corynebacterium pseudotuberculosis was transformed by electroporation, using pNG2, an erythromycin-resistaiice plasmid from C diphtheriae. Corynebacterium pseudotuberculosis cultivated in brain-heart infusion broth was washed 3 times with water, and resuspended to a final concentration of about 5 × 1013 colony-forming units/ml. An electroporator constructed in our laboratory incorporated an electrode with 0.8-mm interelectrode gap, using disposable spectrophotometer cuvettes as containers for electroporation. The pNG2 was prepared in Escherichia coli and 4 to 16 μg of pNG2 dna was mixed with 400-μl amounts of cell suspension in prechilled cuvettes. After incubation on ice for 5 to 10 minutes, the mixture was electroporated at field strengths of up to 18 kV/cm, mixed with 1.5 ml of brain-heart infusion broth, and incubated at 37 C for 2 hours with agitation. Aliquots were then plated on brain-heart infusion blood agar with 15 μg of erythromycin/ml. Corynebacterium pseudotuberculosis was transformed at a maximal efficiency of ≈ 4 × 104 transformants/μg of pNG2 dna. Most total transformants and most transformants per microgram of pNG2 were generated at a field strength of 18 kV/cm. When the concentration of pNG2 dna was varied, the average total number of transformants increased through a concentration of 30 μg/ml, but the efficiency of transformation was highest at the lowest dna concentration. Transformants contained unmodified pNG2.
Characteristics of digital flexor tendon sheath fluid from clinically normal horses
Authors: Malark J. A. , Nixon A. J. , Skinner K. L. , Mohammed H.
Published: January 2024

Physical, biochemical, and cytologic properties of synovial fluid from digital flexor tendon sheaths of clinically normal horses were investigated. Tendon sheath fluid was pale yellow, clear, and did not clot. Volume of fluid within a tendon sheath varied minimally, with a mean of 2.11 ml. Total erythrocyte counts were higher than values observed in normal equine joint fluid, whereas values for total leukocyte count (770 ± 73 cells/mm3), viscosity (6.05 ± 0.58 cs), and protein concentration (7.87 ± 0.03 mg/ml) were similar to those in joint fluid. Large mononuclear cells were the predominant synovial fluid cell type. Mean hyaluronic acid concentration (0.74 ± 0.02 mg/ml) and mucinous precipitate quality were lower than values in joint fluid.
Effect of dietary protein on functional, morphologic, and histologic changes of the kidney during compensatory renal growth in dogs
Authors: White J. V. , Finco D. R. , Crowell W. A. , Brown S. A. , Hirakawa D. A.
Published: January 2024

Two diets similar in caloric density and mineral content, but markedly different in protein content, were used to study the effects of dietary protein on renal function and morphologic and histopathologic changes in dogs that had functional renal tissue reduced by seven-eighths nephrectomy. The effects of moderate protein intake (MPrI = 15% protein; dry-matter basis) and high-protein intake (HPrI = 31% protein; dry-matter basis) were studied for the initial 7 months (period 1 [P1]) after renal mass reduction. Diets were then switched between groups during the following 7 months (period 2 [P2]) to evaluate the effects of increased or decreased protein intake.

The HPrI caused significantly (P < 0.05) greater glomerular filtration rate (gfr) and renal growth than did MPrI during P1. Dogs that maintained HPrI during P1 and MPrI during P2 (group 1) had significant (P < 0.05) reduction in gfr during P2. Dogs that maintained MPrI during P1 and HPrI during P2 (group 2) had significant (P < 0.05) improvement in gfr and renal growth during P2. At the end of the study, renal reserve was evaluated in both groups of dogs before and after group 1 was returned to HPrI for 2 weeks. During this 2-week feeding trial, group-1 dogs had marked improvement in renal reserve, relative to group 2, and gfr increased to the terminal P1 values. Results indicate a possible residual benefit from HPrI during the early phase of compensatory renal growth in the form of functional compensatory memory to HPrI.

The severity of renal lesions was indistinguishable between dogs of dietary groups during both study phases. Plasma electrolyte concentrations rapidly returned to normal range after renal ablation, but mild azotemia and proteinuria persisted throughout most of the study. High protein intake was not associated with increased degree or progression of proteinuria.
Microvascular circulation of the cecum in horses
Authors: Dart Andrew J. , Snyder Jack R. , Julian Dolores , Hinds Dave M.
Published: January 2024

The microvascular circulation of the cecum was studied in 15 adult horses, using microangiography and light microscopy combined with gross studies and scanning electron microscopy of vascular replicas. After heparinization, the horses were euthanatized and the cecum was transected at the cecocolic junction. Blood was flushed free of the circulation with isotonic NaCl and the cecal lumen was slightly distended. In 6 horses, the vascular system was injected with a modified radiopaque medium and evaluated radiographically. Sections evaluated radiographically were also prepared for histologic examination by standard methods. Eight horses were injected with 1 of 2 types of plastics and studied grossly or by scanning electron microscopy. In 1 additional horse, the lateral and medial arteries were injected with different colored plastic for gross studies.

The lateral and medial cecal arteries appear to supply the respective areas of the cecum with minimal mixing of the 2 circulations. The major vascular supply to the cecal apex appeared to be through the medial cecal artery. Both the lateral and medial cecal arteries gave rise to cecal retia, which formed a mesh-like network around the respective veins. Vessels from these retia supplied the cecal tissue and the cecal lymph nodes. The continuation of the retia was through long terminal arteries that coursed around the circumference in the submucosa, forming an extensive submucosal plexus. This plexus supplied both the mucosa, and the tunica muscularis and serosa. Vessels within the longitudinal and circular muscle layers of the muscularis externa ran parallel to the muscle fibers, and consequently, perpendicular to each other. Arteries supplying the mucosa branched into a capillary network as they penetrated the muscularis mucosa at the base of the cecal glands. These capillary networks anastomosed with the networks around adjacent glands at the luminal surface, forming a honeycomb-like pattern. Drainage was facilitated by more sparsely distributed venules that united with venules from adjacent areas and descended to the submucosal veins. These veins were characterized by regular helical smooth muscle constrictions.
Serum tumor necrosis factor activity in horses with colic attributable to gastrointestinal tract disease
Authors: Morris Debra Deem , Moore James N. , Crowe Natalie
Published: January 2024

Over a 24-month period, serum tumor necrosis factor (tnf) activity was determined in 289 horses with colic attributable to gastrointestinal tract disease. Serum tnf activity was quantitated by use of a modified in vitro cytotoxicity bioassay, using WEHI 164 clone-13 murine fibrosarcoma cells. Causes for colic, determined by clinical and laboratory evaluation, exploratory celiotomy, or necropsy included: gastrointestinal tract rupture (gtr); ileal impaction; small intestinal strangulating obstruction (sio); proximal enteritis (pe); transient small intestinal distention; large-colon displacement; large-colon vovulus; large-colon impaction; colitis; small-colon obstruction; peritonitis; and unknown. Each diagnosis was placed into 1 of 3 lesion categories: inflammatory disorders (gtr, pe, colitis, peritonitis); strangulating intestinal obstruction (sio, large-colon volvulus); and nonstrangulating intestinal obstruction (ileal impaction, transient small intestinal distension, large-colon displacement, large-colon impaction, small-colon obstruction, unknown). The prevalence of high serum tnf activity and/or mortality were evaluated. Differences were tested at significance level of P < 0.05.

Approximately 20% of the 289 horses has serum tnf activity greater than that found in clinically normal horses (> 2.5 U/ml). Twenty-three horses (8%) had marked increase in serum tnf activity (≥ 10 U/ml) which was more prevalent among horses with sio and pe than in horses of other diagnostic groups, except those with gtr. Mortality and marked increase in serum tnf activity were greater in horses with intestinal inflammatory disorders or strangulating intestinal obstruction than in horses with nonstrangulating intestinal obstruction. Similarly, a greater proportion of the horses that died had markedly high serum tnf activity than did horses that lived. Mortality of horses with serum tnf ≥ 10 U/ml was greater than that of horses with serum tnf activity < 10 U/ml. Results indicate possible association between colic and serum tnf activity in horses and that high mortality may be associated with horses with markedly increased serum tnf activity.
Growth hormone concentrations in plasma of healthy pigs and pigs with atrophic rhinitis
Authors: Ghoshal Nani G. , Niyo Yosiya , Trenkle Allen H.
Published: January 2024

Plasma concentrations of porcine growth hormone (pgh) were similar in healthy pigs and those with atrophic rhinitis (ar), therefore, observed reduced growth rates and feed efficiency in naturally infected pigs with ar were not attributed to low concentrations of plasma pgh. Also, pituitary glands in both groups of pigs were responsive to growth hormone-releasing hormone (ghrh) challenge by increasing pgh secretion. Administration of clonidine hydrochloride to pigs naturally infected with ar failed to elicit any significant change (5.3 ± 1.4 ng/ml) in the plasma concentration of pgh within a 45-minute bleeding interval. The pretreatment concentrations of pgh were similar in specific-pathogen-free toxin-treated and specific-pathogen-free control groups, but they increased significantly in toxin-treated pigs (20.7 ± 8.2 ng/ml) within 15 minutes after ghrh injection. Porcine growth hormone release in toxin-treated pigs was variable; however, all pigs did not respond to ghrh administration: 3 responded with an increase in pgh release (35.6 ± 10.6 ng/ml), 2 did not respond (6.7 ± 0.5 ng/ml), and 1 had a decrease in pgh release (3.9 ng/ml).

Therefore, the observed reduced growth rates reported in the literature may be attributed to factors at the target level of pgh action, such as insufficient or down-regulation of pgh receptors, changes or impaired ability in the pgh receptor-binding characteristics, and inability of pgh receptor complex to transduce signal. Toxins are known to modulate signal transduction pathways. It has been speculated that serotype-D Pasteurella multocida toxin may influence growth by its effect on signal transduction from pgh receptor complex on the cell membrane to the interior of the cell. This would account for the presence of high concentrations of pgh in the plasma and a functionally competent hypophysis cerebri, which responded to ghrh injection that have retarded growth in pigs affected with ar.
Effects of diet on acidic and neutral goblet cell populations in the small intestine of early weaned pigs
Authors: Dunsford B. R. , Haensly W. E. , Knabe D. A.
Published: January 2024

Effects of dietary manipulation on Alcian blue-positive (ab +) and periodic acid-Schiff-positive (pas+) goblet cell populations were determined for the villi and intestinal crypts in the small intestine of early weaned pigs. Pigs were weaned at 21 days of age and samples from the distal portion of the duodenum and the middle and distal portions of the jejunum were obtained when pigs were 21, 24, 27, 30, 33, and 36 days old. Pigs were assigned to 1 of 3 dietary treatments; all diets contained 20% protein, on the basis of hydrolyzed casein, soybean meal, or corn-soybean meal. By day 24, three days after weaning, the populations of ab+ and pas+ goblet cells were markedly decreased, regardless of diet. Goblet cell populations in the villi tended to increase from 3 to 15 days after weaning, whereas those in the intestinal crypts remained low throughout the study. Differences between any of the dietary treatments were not apparent for ab+ or pas+ goblet cell populations in the villi or in the intestinal crypts. It appeared that early weaning per se, and not diet, was the primary cause for decreases in goblet cell populations.
Antibody response to glycoprotein I in maternally immune pigs exposed to a mildly virulent strain of pseudorabies virus
Authors: van Oirschot J. T. , Daus F. , Kimman T. G. , van Zaane D.
Published: January 2024

To study the antibody response to glycoprotein I (gI) of pseudorabies virus (prv) in maternally immune pigs, 3 groups of 6 pigs were given low doses of the mildly virulent Sterksel strain of prv at 3 and 11 weeks of age. Group A consisted of seronegative pigs; groups B and C consisted of pigs with maternal antibodies deficient of antibodies to gI. At 3 weeks of age, 3 pigs of each group were inoculated intranasally with 102.5 plaque-forming units (groups A and B), or with 103.5 plaque-forming units (group C) of prv. The 3 other pigs in each group were contact-exposed to the inoculated pigs.

In group A, 4 of 6 pigs shed virus and all developed antibodies to gI of prv and produced prv-specific IgM and virus-neutralizing antibodies. In groups B and C, 10 pigs shed virus and all developed low and inconsistent titers of gI antibodies, whereas only 3 pigs produced prv-IgM antibodies with low titers. Thus, after prv infection of pigs with high concentrations of maternal antibodies deficient of gI antibodies, the antibody responses to prv were severely inhibited.

The pigs were reinoculated with 103 plaque-forming units of the same virus 8 weeks after the first inoculation. The pigs in group A did not respond at all, as they were immune. The pigs in groups B and C shed considerable amounts of virus. Three pigs had a clear secondary antibody response to gI, whereas the others developed an early to normal antibody response to gI. None of the pigs mounted a secondary neutralizing antibody response to prv.

We concluded that inoculation of pigs having high titers of gI-deficient maternal antibodies with low doses of a mildly virulent prv, induced low to undetectable concentrations of antibodies to gI.
Use of polymerase chain reaction to detect latent channel catfish virus
Authors: Boyle John , Blackwell Jeanne
Published: January 2024

Polymerase chain reaction was used to detect an economically important herpesvirus, channel catfish virus (ccv). A segment of the viral dna was sequenced and oligonucleotide primers were produced from that sequence. After the primers were tested for the possibility of hybridization to catfish dna, they were used to prime the polymerase chain reaction, using pure ccv dna, ccv dna added to catfish dna, and dna from catfish infected and not infected with ccv. In all cases, the method proved to be simple and sensitive in its detection of ccv dna. When catfish dna was present, < 0.1 pg of ccv dna was detectable. Channel catfish virus dna in a latent carrier of ccv was readily detectable.
Evaluation of a topically administered carbonic anhydrase inhibitor (MK-927) in normotensive and glaucomatous Beagles
Authors: King Tracey C. , Gum Glenwood G. , Gelatt Kirk N.
Published: January 2024

A new topically administered anhydrase inhibitor, MK-927, was evaluated for its ocular hypotensive activity in normotensive and glaucomatous Beagles. Single- and multiple-dose studies were performed. Six concentrations of the drug were evaluated in the single-dose study and the 2% solution was used for multiple-dose evaluation. The decrease in intraocular pressure (iop) was greater in glaucomatous Beagles at the higher concentrations of the drug. The 2 and 4% solutions of MK-927 significantly lowered iop (mean, 5 mm of Hg; sem ± 1.6 and sem ± 1.2, respectively) in normotensive and glaucomatous Beagles. In the multiple-dose study, iop was significantly decreased in the normotensive (mean, 4 mm of Hg; sem ± 0.74) and glaucomatous Beagles (mean, 9 mm of Hg; sem ± 1.2). The maximal effect was observed by day 4. A contralateral effect was found in glaucomatous Beagles, with the maximal effect on day 4.
Clinical and pathologic effects of oral administration of transmissible gastroenteritis vaccine to gnotobiotic pigs
Authors: Waxier G. L.
Published: January 2024

Pigs from 3 fitters kept under gnotobiotic conditions were inoculated orally with virulent transmissible gastroenteritis (tge) virus, a tge vaccine, or Hank’s balanced salt solution at 2 days of age and then euthanatized at intervals ranging from 1 to 7 days after inoculation. Pigs exposed to the vaccine had clinical evidence of diarrhea and weakness. Lesions resembling those of tge were revealed grossly, microscopically, and by scanning electron microscopy. Viral antigen was seen in intestinal epithelial cells by the direct fluorescent antibody technique. The disease induced by the vaccine virus had a longer incubation period and lesions were less severe than that induced by the virulent virus.
Measurements of left and right ventricular pressures and their derivatives by transcutaneous puncture in rats
Authors: Hamlin Robert L.
Published: January 2024

Eighteen rats were anesthetized with xylazine/ketamine and placed in right lateral recumbency, and a small incision was made in the skin of the left hemithorax. A 21-gauge, 1-inch, short-beveled hypodermic needle, attached directly to a pressure transducer filled with degassed saline solution, was advanced through the incision into the left ventricle and then advanced through the septum into the right ventricle. High-fidelity tracings of right and left ventricular pressures and their derivatives were obtained through this approach in 13 rats. In 5 rats, measurements of right ventricular pressures were obtained by additional right ventricular puncture through the incision in the left hemithorax. Right and left ventricular pressures were recorded on single occasions in 18 rats, twice at 2-week intervals in 6 rats, and 3 times at 2-week intervals in 3 rats. Minimal hemopericardium was observed, but most rats had evidence of hemorrhage on the visceral pericardium. Left and right ventricular pressures can be measured rapidly, safely, and repeatedly in anesthetized rats by this method.
Vaccination of Lewis rats against Mycoplasma arthritidis- induced arthritis
Authors: Washburn Leigh Rice , Hirsch Shannon , McKenzie Matt , Voelker LeRoy L.
Published: January 2024

The nature of Mycoplasma arthritidis antigens responsible for eliciting protective immunity in rats was studied by inoculation of rats with mycoplasmal components that had been subjected to a variety of physical and chemical treatments. All inocula tested induced good protection against development of clinical illness, as assessed by changes in body weight and appearance of joint swelling and/or temporary hind limb paralysis. Although all preparations stimulated development in inoculated rats of high titer of antimycoplasmal antibodies measured by elisa, the complement-fixation antibody response was poor and, in some cases, lacking altogether. This indicated that completion-fixation antibodies may not be involved in protecting rats against M arthritidis-indaced illness.

Protective antigens were stable to heat (100 C for 10 minutes), formalin, and denaturation by sodium dodecyl sulfate (sds). Inoculation with membrane and soluble cytoplasmic fractions was protective, as was inoculation with 5 M arthritidis fractions separated according to molecular weight by sds-polyacrylamide gel electrophoresis (sds-page). For this latter experiment, rat antisera obtained after vaccination, but prior to challenge exposure, were tested by immunoblot analysis against electrophoretically separated M arthritidis membrane proteins. Interestingly, all antisera from these rats recognized antigens migrating far outside the molecular weight range of the cell fractions with which rats were inoculated. This indicated either that the protective antigens may be composed of numerous antigenically related subunits that separated by sds-page into a variety of molecular weight ranges or that a few major antigens may exist in several forms or phases within a given population of M arthritidis.
Evaluation of peritoneal fluid following intestinal resection and anastomosis in horses
Authors: Hanson R. Reid , Nixon Alan J. , Gronwall R. , Meyer D. , Pendergast J.
Published: January 2024

Postoperative abdominal fluid changes were compared in 2 groups of horses; those undergoing double small-colon resection and anastomosis (n = 10) and those undergoing exploratory celiotomy alone (n = 5). Peritoneal fluid was collected before surgery and on postoperative days 1, 3, 5, and 7. Total and differential nucleated cell counts, rbc numbers, and total protein and fibrinogen concentrations were evaluated. In both groups, all values were significantly higher than normal on the first postoperative day (after small-colon resection and anastomoses, wbc = 130,350 ± 23,310 cells/µl, rbc = 7,389,000 ± 6,234,000 cells/µl, total protein = 3.63 ± 0.16 g/dl; after exploratory celiotomy alone, wbc = 166,620 ± 34,340 cells/µl, rbc = 295,000 ± 86,070 cells/µl, total protein 4.38 ± 0.54 g/dl). The number of total peritoneal nucleated cells and rbc significantly decreased after the first postoperative day, whereas total protein and fibrinogen concentrations, percent neutrophils, and percent mononuclear cells remained unchanged. None of the values had returned to normal by postoperative day 7 (after small-colon resection and anastomoses, wbc = 45,600 ± 8,765 cells/µl, rbc= 95,390 ± 53,380 cells/µl, total protein = 4.39 ± 0.23 g/dl; after exploratory celiotomy alone, wbc= 43,340 ± 7,746 cells/µl, rbc = 12,860 ± 11,790 cells/µl, total protein = 3.92 ± 2.20 g/dl.) The resection and anastomosis group had a significantly lower total protein concentration on the first postoperative day and a significantly higher mean total rbc count over the entire 7-day postoperative evaluation than did horses that underwent celiotomy alone. Other values in the 2 groups of horses did not differ significantly. As a result, there was insufficient evidence to conclude that resection and anastomosis of the small colon in healthy horses causes a different inflammatory response than does manipulation of the intestine alone.
Effect of experimentally induced endotoxemia on serum interleukin-6 activity in horses
Authors: Morris Debra Deem , Moore James N. , Crowe Natalie , Moldawer Lyle L.
Published: January 2024

A study was conducted to determine whether serum interleukin-6 (il-6) activity increased in horses during experimentally induced endotoxemia and whether serum il-6 activity correlated to changes in clinical or laboratory data. Six clinically normal horses were given endotoxin iv (30 ng/kg of body weight) in 0.9% NaCl solution over 1 hour. Five of these and 1 additional horse served as controls and were given only 0.9% NaCl solution. Venous blood, for determination of serum il-6 activity and wbc count, was collected before and at various times through 8 hours after the start of endotoxin or NaCl infusion. Rectal temperature and heart and respiratory rates were recorded throughout the study period. Serum il-6 activity was determined by bioassay of proliferation of the B13.29 clone B.9 hybridoma cell line. From 1.5 through 5 hours after start of the infusion, serum il-6 activity was significantly (P < 0.05) increased in horses given endotoxin. Mean peak serum il-6 activity was observed between 3 and 4 hours. In response to endotoxin infusion, horses became lethargic, tachycardic, and febrile. Leukopenia developed by 1 hour, followed by leukocytosis at 8 hours. Significant (P < 0.05) positive association and linear correlation were apparent between mean serum il-6 activity and mean rectal temperature in the group of horses that were given endotoxin. Changes from baseline were not evident in any of the clinical or laboratory values in horses given only NaCl solution.
Evaluation of a single injection of 99mTc-labeled diethylenetriaminepentaacetic acid for measuring glomerular filtration rate in horses
Authors: Walsh Donald, M. , Royal Henry D.
Published: January 2024

Glomerular filtration rate (gfr) was measured in 12 clinically normal horses, using the standard inulin clearance method, and values were compared with values for 2 methods, using a single rapid iv injection of 99mTc-la-beled diethylenetriaminepentaacetic acid (99mTc-dtpa). The first 99mTc-dtpa method used a 2-compartment model to calculate gfr blood clearance of the tracer. The second method used sequential digital gamma camera images of the kidneys to determine fractional accumulation of the total dose of the tracer in the kidneys (percentage of injected dose, gamma camera) from 0 to 10 minutes after radionuclide administration. Linear correlation among the 3 methods was determined.

Mean (± SD) gfr, using the inulin clearance method, was 154.67 ± 42.28 ml/min/100 kg of body weight. Mean gfr, using the 2-compartment blood clearance curve, was 146.92 ± 27.49 ml/min/100 kg. Mean gfr, using percentage of injected dose (gamma camera method) was 154.7 ± 22.00 ml/min/100 kg. The percentage of injected dose (gamma camera method) did not correlate significantly to the inulin clearance results. However, a significant (r = 0.666, P < 0.018) correlation was observed between the inulin method and the 99mTc-dtpa blood clearance method. Significant (P < 0.0001) difference also was observed in the split function of the equine kidneys, with gfr of the right kidney contributing 60.1 ± 9.12% of the total function, as determined by 99mTc-dtpa gamma camera imaging.

Because the 99mTc-dtpa blood clearance method does not require urine collection, it may be a more practical procedure to measure gfr in the horse.
Lymphoscintigraphy in healthy dogs and dogs with experimentally created thoracic duct abnormalities
Authors: Hodges Carlos C. , Fossum Theresa W. , Komkov Andrea , Hightower Dan
Published: January 2024

Lymphoscintigraphic evaluation of the thoracic duct (td) was performed in 10 healthy and 12 dogs with experimentally created td abnormalities (6 dogs with td lacerations and 6 dogs with cranial vena ligations). Complete imaging took 4 hours and caused no adverse effects or complications. Lymphoscintigraphy of healthy dogs failed to image the td; however, background activity in the abdomen and thorax, and radioactivity in the kidneys, bladder, liver, and heart were noticed.

Lacerations and transections of the td were experimentally created in 6 dogs to ascertain whether td rupture could be detected with lymphoscintigraphy. Lymphoscintigraphy was performed within 48 hours of creating the td defect. There was no significant difference in the scintigraphic pattern of healthy dogs and those with experimentally created td defects.

Ligation of the cranial vena cava was performed in 6 dogs; 3 dogs developed chylothorax. In those 3 dogs, diffuse radioactivity was imaged in the thorax and was compatible with thoracic lymphangiectasia. In one of these dogs, linear activity consistent with the td and localized regions of radioactivity cranial to the heart (compatible with the mediastinal lymph nodes) were noticed. Lymphoscintigraphic findings in these dogs correlated with lymphangiographic findings.
Bronchial circulation during prolonged exercise in ponies
Authors: Manohar Murli , Duren Stephen E. , Sikkes Bridget P. , Day Jennifer , Baker John P.
Published: January 2024

Tracheal, bronchial, and renal blood flow were studied in 8 healthy ponies at rest and during exercise performed on a treadmill at a speed setting of 20.8 km/h and 7% grade (incline) for 30 minutes. Blood flow was determined with 15-μm-diameter radionuclide-labeled microspheres that were injected into the left ventricle when the ponies were at rest, and at 5, 15, and 26 minutes of exertion. Heart rate and mean aortic pressure increased from resting values (40 ± 2 beats/min and 124 ± 3 mm of Hg, respectively) to 152 ± 8 beats/min and 133 ± 4 mm of Hg at 5 minutes of exercise, to 169 ± 6 beats/min and 143 ± 5 mm of Hg at 15 minutes of exercise, and to 186 ± 8 beats/min, and 150 ± 5 mm of Hg at 26 minutes of exercise. Tracheal blood flow at rest and during exercise remained significantly (P < 0.05) less than bronchial blood flow. Tracheal blood flow increased only slightly with exercise. Vasodilation caused bronchial blood flow to increase throughout exercise. Pulmonary arterial blood temperature of ponies also increased significantly (P < 0.05) with exercise and a significant (P < 0.005) correlation was found between bronchial blood flow and pulmonary arterial blood temperature during exertion. At 5 minutes of exercise, renal blood flow was unchanged from the resting value; however, renal vasoconstriction was observed at 15 and 26 minutes of exercise. We concluded that bronchial circulation of ponies increased with exercise in close association with a rise in pulmonary arterial blood temperature. Also, increased thermal burden necessitated redistribution of blood flow away from kidneys late in exercise.