bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of blood flow during moderate and strenuous exercise in ponies (Equus caballus)
Authors: Parks Christine M. , Manohar Murli
Published: February 2025

SUMMARY AND CONCLUSIONS

Blood flow to the brain, heart, kidneys, diaphragm, and skeletal muscles was studied at rest and during graded treadmill exercise, using radionuclide-labeled microspheres (15 µm diameter), in 11 healthy adult ponies. Hemodynamic changes brought about by exercise included marked increases in cardiac output, mean aortic pressure, left ventricular end-diastolic pressure, and right ventricular systolic and end-diastolic pressures. Blood flow to the brain stem and cerebral hemispheres was unchanged during both moderate exercise (heart rate = 154 ± 3 beats/min) and severe exercise (heart rate = 225 ± 7 beats/min). Despite marked hypocapnia during severe exercise, cerebellar blood flow increased by 32% above control value (94 ± 7 ml/min/100 g). Myocardial blood flow increased transmurally with both levels of exercise. The endo:epi (inner:outer) perfusion ratio for the left ventricle and the interventricular septum decreased during exercise. It was, however, not different from unity. During severe exercise, renal blood flow decreased to 19% of its control value. Blood flow to the diaphragm exceeded that to the skeletal muscles during both intensities of exercise. Blood flow to the exercising muscles of the brachium and thigh increased by 31- to 38-fold during moderate exercise and by 70- to 76-fold during severe exercise. It is concluded that the cardiovascular response to strenuous exercise in the pony included an increase in blood flow to the cerebellum, myocardium, diaphragm, and exercising skeletal muscles, while blood flow was diverted away from the kidneys. It would appear that the pony's cardiovascular response to severe exercise is similar to that of persons.
Modification of the effects of aflatoxin B1 and warfarin in young pigs given selenium
Authors: Davila J. C. , Edds G. T. , Osuna O. , Simpson C. F.
Published: February 2025

Selenium may be related to the hepatic metabolism of the coumarin compounds aflatoxin B1 and warfarin. Selenium evidently increased the pharmacologic activity of warfarin, probably due to a displacement of warfarin from albumin by selenium, the close relationship among selenium, vitamin E, and sulphur-containing groups (eg, glutathione), or the antioxidant effect of selenium. A diet containing selenium in a concentration of 2.5 mg/kg of feed was protective against the toxic effects of both coumarins in pigs given 4 daily oral doses of 0.2 mg/kg of body weight. Selenium, as glutathione peroxidase, at least in part, protects the hepatic cells against the toxic effects of aflatoxin B1 and warfarin. The protection was demonstrated by alteration of clinical responses and hematologic (prothrombin times), electrophoretic, and clinical chemistry values. It also was demonstrated that selenium at 2.5 mg/kg of feed does not produce toxic effects; however, dietary selenium at a concentration of 5 mg/kg (and in the presence of both toxic agents) was toxic for young pigs within the 3-week experimental period. Warfarin was more active as an anticoagulant than aflatoxin B1.
Considerations of the structure of sesquiterpene lactones on biological activity: Influence of the α-methylene-γ-lactone moiety on mast cell degranulation
Authors: Elissalde M. H. , Ivie G. W. , Rowe L. D. , Elissalde G. S.
Published: February 2025

Mast cell degranulation was quantitated by measuring percentage of histamine release, 45Ca2+ ion influx, or c-AMP cellular levels after stimulation with various concentrations of the sesquiterpene lactones hymenovin, helenalin, or tenulin. Hymenovin and helenalin, which contain an α-methylene-γ-lactone moiety, produced extensive degranulation. Alkylation of the α-methylene-γ-lactone group of these compounds with the amino acid cysteine before mast cell stimulation drastically reduced the capacity of these lactones to stimulate histamine release. Tenulin, which does not contain an α-methylene-γ-lactone moiety, generally stimulated degranulation approximately equal to that of cysteine-treated hymenovin or helenalin. These data indicate that sesquiterpene lactones containing α-methylene-γ-lactone are potent stimulators of mast cell degranulation. This phenomenon may have a significant role in the toxicity of some sesquiterpene lactones of poisonous plants when ingested by livestock.
Standard antisera produced in ponies for the identification of bovine mycoplasmas: Comparative growth-inhibition results from six laboratories
Authors: Stalheim O. H. V. , Cottew G. S. , Freundt E. A. , Koski T. A. , Leach R. H. , Perreau P. , Stone S. S.
Published: February 2025

Antisera to 10 mycoplasmal species of bovine origin were produced in 10 ponies and were distributed for evaluation in growth-inhibition tests at 6 laboratories in Australia, England, Denmark, France, and the United States. Except for a few failures with some antigens produced at the 6 laboratories, the antisera induced large zones of growth inhibition in homologous, but not heterologous, systems. These antisera may be useful as standard reagents for the identification of the bovine mycoplasmas.
Infectivity in sheep of blood lymphocytes from bovine leukemia virus-infected cows with different nuclear pocket prevalences
Authors: Weber A. F. , Schmerr M. J. , Sorensen D. K. , Bingham C. , Pomeroy K. , Miller J. M. , Van Der Maaten M. J.
Published: February 2025

The infectivity for the bovine leukemia virus (blv) of bovine blood lymphocytes, with varying lymphocyte nuclear pocket (lnp) prevalence, was studied by intradermal injection of buffy coat leukocytes from cows into sheep.

Thirty-five sheep were assigned to 3 groups of 9, 11, and 15, respectively, as recipients of blood leukocytes from individual cows as follows: 9 leukocyte donor cows included 3 blv-seropositive cows with high (≥ 2.0%) lnp prevalence (group 1); 3 blv-seropositive cows with low (< 0.5%) lnp prevalence (group 2); and 3 blv-seronegative cows with increased (≥ 0.5%) lnp prevalence (group 3).

The 9 sheep in group 1 became blv-seropositive by postinoculation day (pid) 57 as determined by the agar-gel immunodiffusion test; 2 of 11 sheep in group 2 became agar-gel immunodiffusion seropositive by pid 40; none of the 15 sheep of group 3 became seropositive by pid 92.

Seemingly, there is a real difference in infectivity among blv-seropositive cattle which is related to lnp prevalence, and seronegative cattle with increased lnp prevalence may be noninfectious, ie, were not carrying covert blv virogene.
Characteristics of the polyriboinosinic acid:polyribocytidylic acid assay for noncytopathogenic bovine viral diarrhea virus
Authors: Rossi Charles R. , Kiesel George K.
Published: February 2025

The use of polyriboinosinic acid:polyribocytidylic acid (poly I:C) for noncytopathogenic bovine viral diarrhea virus (nc-bvdv) assay (pinba) was studied. Several viruses were tested for their suitability as test challenge viruses. In addition to vesicular stomatitis virus, which previously was shown to be a suitable challenge virus, bovine enteroviruses also were found to be suitable, whereas infectious bovine rhinotracheitis virus and parainfluenza type 3 virus were only marginally suitable. Bovine embryonic skin (bes) cultures developed resistance to pinba within a few in vitro passages, whereas bovine embryonic lung (bel) cultures did not. At certain passages, bes cultures were 500,000 times more resistant than bel cultures. To determine whether the difference in viral titers on bel and bes cultures was due to nc-bvdv replication, pinba and fluorescent antibody assays were compared on the cultures. Resistance of bes cultures to pinba was not due to an inability of the virus to replicate in the cultures, but was due to an inability of pinba to detect the virus. Viral titers were comparable by fluorescent antibody assay titers on bes and bel cultures, but were considerably higher than viral titers on bes cultures with pinba. Variations in viral titers, using pinba on bel cultures, were observed and were considered to be due to cultural conditions, such as the presence of low levels of bvdv antibodies in bovine fetal serum used in the medium. Treatment of bel cultures with poly I:C or interferon showed that nc-bvdv was sensitive to interferon as determined by virus-yield reduction.
Transfer of adult Strongylus vulgaris via stomach tube
Authors: Hofing G. L. , Bennett D. G.
Published: February 2025

Patent infections with Strongylus vulgaris were established in 6 of 8 helminth-free ponies given 41 to 101 adult worms via nasogastric tube. The parasites were removed from the cecum and ventral colon and transferred within 1 to 2 hours of the death of the donor horses. Eggs were found in the feces of the recipients in 2 or 3 days; egg counts reached maximum, 28 eggs per gram of feces, at 4 weeks after ponies were inoculated.

In 6 ponies euthanatized 3 to 7 weeks after parasitic transfers were done, 28% of the inoculated worms were found alive at necropsy. A 7th pony was maintained as a donor for establishing infections for chemotherapy trials and, although never passing more than 6 eggs per gram of feces, shed infective larvae over a period of 2 years.
Response of gilts with delayed puberty to pregnant mare serum gonadotropin or estrogen
Authors: Hurtgen John P. , Johnston Shirley D.
Published: February 2025

The effect of pregnant mare serum gonadotropin (pmsg) or estradiol cyclopentylpropionate (ec) on the induction of estrus, duration of estrus, and serum progesterone concentration after estrus was evaluated in 8 gilts with delayed puberty. Four gilts were given 500 IU of pmsg im and 4 were given 2 mg of ec, im. The inactive status of the ovaries at the time of treatment was verified by serum progesterone values of < 0.5 ng/ml in serial samples collected before treatment.

The 4 ec-treated gilts came into estrus at a mean of 3.5 days after treatment, but 1 of the gilts did not form corpora lutea. Three pmsg-treated gilts came into estrus at a mean of 4.0 days after treatment. The remaining pmsg-treated gilt remained anestrus and did not form corpora lutea. The mean duration of estrus in ec-treated gilts was 5.25 days compared with 2.0 days for pmsg-treated gilts (P < 0.05). Serum progesterone concentrations were higher in pmsg-treated gilts than in ec-treated gilts at 8, 11, and 17 days after treatment (P < 0.05).
Interaction of dichlorvos-crotoxyphos insecticide with phenothiazine anthelmintic in sheep with or without Haemonchus and Trichostrongylus infections
Authors: Mohammad Fouad K. , St. Omer Vincent E. V.
Published: February 2025

The temporal interaction of an emulsifiable mixture of 2.3% dichlorvos and 10% crotoxyphos with phenothiazine anthelmintic was studied in 8 groups of 5 lambs each, free from or parasitized with Haemonchus and Trichostrongylus spp. Each lamb in 1 of 3 parasitized groups and 1 of 3 nonparasitized groups was treated with phenothiazine orally (12.5 g initially and 4 days later with 6.25 g every 3 days for 9 treatments) and/or the mixture of dichlorvos and crotoxyphos dermally (1,550 ml of 0.25% emulsion sprayed every 2 weeks for 3 applications). Two groups served as controls.

Onset of clinical signs of toxicosis, lethality, and erythrocyte acetylcholinesterase (eace) activity were monitored. After each dichlorvos-crotoxyphos mixture spray, clinical signs of toxicosis were seen within 40 minutes in parasitized and nonparasitized lambs regardless of concurrent phenothiazine treatment. Phenothiazine alone was not toxic and did not inhibit eace activity. The eace activities of dichlorvos-crotoxyphos mixture-sprayed lambs were significantly (P < 0.05) depressed regardless of parasitism or concurrent phenothiazine treatments. The severity of inhibition increased with each dichlorvos-crotoxyphos mixture spray, but eace activity recovered within 48 hours after each spray although base-line values were never attained. There was no apparent potentiation of the toxic effects of the dichlorvos-crotoxyphos mixture by phenothiazine.
Leptospirosis in rodents from an arid environment
Authors: Songer J. Glenn , Chilelli C. J. , Reed R. E. , Trautman R. J.
Published: February 2025

Rodents (n = 358) were trapped from 6 locations in Arizona, including 2 dairies, 2 swine raising operations, and 2 areas where domestic animal access was limited. Isolates of Leptospira interrogans serovar ballum were obtained from 3 house mice (Mus musculus) trapped in dairies. Leptospira were seen in silver-stained kidney sections of 10.4% of the rodents. The usefulness of serologic data in detecting leptospiral infection in these rodents was uncertain because so few animals yielded isolates that valid comparisons of culture positives to serologic positives were not possible. Titers ≥ 1:160 were obtained to serovars autumnalis, ballum, bratislava, canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona. Nearly 60% of the rodents had microscopic lesions in kidneys, including 20 of 34 (59%) of those in which leptospira were seen.
Mice and rabbit models for oral and percutaneous absorption and disposition of amphoteric surfactant C31G
Authors: Michaels E. B. , Hahn E. C. , Kenyon A. J.
Published: February 2025

A topical antimicrobial agent (C31G), composed of amphoteric surfactants (alkyl betaines and alkyl amine oxides), had a significant (P < 0.001) and concentration dependent rate of percutaneous absorption in mice and rabbits. Percutaneous absorption studies (3 concentrations for 3 exposure periods) in mice indicated that dermal interaction resulted in nonlinear changes for rate of penetration and transport as a function of exposure and concentration.

Kinetic studies of absorption and disposition after oral dosing in mice with [3H]C31G were used to determine the body burden (0.21 g/kg of body weight) at a no effect level. Dermal penetration (P) and transport (T) resulting from percutaneous exposure at variations of time and dosage concentrations were shown to fit the equation T = a + k ln t. The regression coefficient k represents the characteristic change of T with exposure time (t). For low concentrations k equaled 1.89 and at the high concentration k equaled 2.68. This increase of T indicated the interaction of the agent with the dermal barrier at high concentrations. Dermal transport in the rabbit was less than one-fourth of that in the mouse.

Excretion of C31G after oral or dermal dosing was predominantly renal at higher dosage levels, whereas fecal excretion dominated at the lowest dosage levels. The half-life of [3H]C31G in the mouse was 68 hours and 86 hours in the rabbit. Data and statistical methods allowed prediction of the effects of daily exposures.
Acepromazine-xylazine combination in dogs: Antagonism with 4-aminopyridine and yohimbine
Authors: Cronin Michael F. , Booth Nicholas H. , Hatch Roger C. , Brown John
Published: February 2025

Groups of fasted atropinized crossbred dogs of both sexes were injected im with a standard dosage of a xylazine-acepromazine combination (2.2 mg/kg and 0.5 mg/ kg, respectively). Righting reflex was uniformly lost and considered to be the point of maximum sedation. After maximal sedation, dogs were injected iv with 4-aminopyridine (4-ap, 0.5 mg/kg), yohimbine (0.25 mg/kg), or a combination of 4-ap and yohimbine. Controls were given (iv) 1 ml of saline solution.

The 4-ap, yohimbine, and 4-ap + yohimbine significantly reduced walk times (time to arousal and ability to walk on a leash) from a control value of 43.1 minutes to 7.6, 4.4, and 1.9 minutes, respectively (P < 0.05). Relapse to unconsciousness did not occur with any antagonist regimen and recovery was uneventful.

In 3 dogs sedated with the xylazine-acepromazine combination supplemented with halothane having surgically placed cannulas and electrodes for measurement of electroencephalo-, electrocardio-, and electromyographic (eeg, ecg, and emg) responses, arterial blood pressure, and respiratory rates and depth, iv injection of 4-ap + yohimbine caused transient femoral arterial hypotension with tachycardia, increases in respiratory rate, depth, and minute volume, increased emg and eeg activities preceding and accompanying gross movements, slight speeding of ecg, and behavioral arousal within 3 minutes. Increased heart rate also was observed in intact dogs given yohimbine. Increased rate and depth of respiration also was seen in all intact dogs given antagonists.

Curiously, the xylazine-acepromazine combination did not induce arterial hypotension as expected from the product literature. To what extent pretreatment with atropine sulfate may have counteracted this effect is unknown.

The results indicate that the xylazine-acepromazine combination produced a state of relaxation, immobility, deep sedation, and moderate analgesia that could be useful in restraint, preanesthetic medication, and minor surgical procedures in veterinary medicine. A major advantage of this sedative combination is that it can be safely antagonized with 4-ap and yohimbine.
Serum γ-glutamyl transpeptidase activity in healthy cats and cats with induced hepatic disease
Authors: Spano Joseph S. , August John R. , Henderson Ralph A. , Dumas Martha B. , Groth A. H.
Published: February 2025

Activities of serum γ-glutamyl transpeptidase (ggt), alkaline phosphatase (alp), and alanine aminotransferase (alt) were determined in healthy cats and in cats before and after treatment: common bile duct ligation, carbon tetrachloride administration, sham surgery, or anesthesia only. Significant (P < 0.01) increases in serum ggt, alp, and alt occurred in cats with ligated bile ducts. Significant (P < 0.01) increases in serum alt occurred in carbon tetrachloride-treated cats. Increases of serum ggt, alp, or alt were not observed in cats subjected to sham surgery or anesthesia only compared with these cats’ baseline values and values in healthy cats.

Tissue ggt activity was measured in liver, renal cortex, jejunal mucosa, and bile ducts. There was a 1.5-fold increase in ggt activity in livers of cats with ligated bile ducts, compared with that in livers of healthy cats.
Augmented T lymphocyte responses and abnormal B lymphocyte numbers in goats chronically infected with the retrovirus causing caprine arthritis-encephalitis
Authors: DeMartini J. C. , Banks K. L. , Greenlee A. , Adams D. S. , McGuire T. C.
Published: February 2025

Caprine arthritis-encephalitis is a retrovirus-induced disease resulting in lymphoproliferative lesions of the cns and joints. Peripheral blood leukocytes of chronically infected goats were analyzed for the types of cells present and for their reactivity to viral antigen and polyclonal stimulants. Two of 9 infected goats had abnormal numbers of B lymphocytes—one elevated and the other deficient. Lymphocyte reactivity to viral antigens was transiently detectable by a lymphoblastogenic assay in 5 of the 9 goats. The reactive cells were peanut agglutinin-negative T lymphocytes. Concanavalin A induced more division in T lymphocytes of infected goats than in lymphocytes of noninfected goats, whereas the reactions to phytohemagglutinin, pokeweed mitogen, and bacterial lipopolysaccharide were no different in the 2 goat groups. It is concluded that goats infected by the caprine arthritis-encephalitis virus have antigen-reactive T lymphocytes and that infection promotes the response to a nonspecific T-cell stimulant.
Growth of ovine granulocyte-macrophage precursors in vitro without exogenous colony-stimulating activity
Authors: Chandra P. , Joel D. D. , Chanana A. D.
Published: February 2025

Ovine granulocyte-macrophage colony-forming units (cfu-gm) from peripheral blood and bone marrow were cultured in vitro. The colony-stimulating activity (csa) was provided by various conditioned-media previously reported to contain csa and by homologous sheep serum (ss). The maximum number of cfu-gm was observed in the cultures containing ss without the addition of exogenous csa. The cfu-gm appeared earlier in the cultures containing bone marrow cells when compared to the peripheral blood cfu-gm. Replacement of ss by bovine fetal serum resulted in suboptimal growth of ovine cfu-gm.
Identification of porcine transmissible gastroenteritis virus in house flies (Musca domestica Linneaus)
Authors: Gough P. M. , Jorgenson R. D.
Published: February 2025

Transmissible gastroenteritis (tge) virus was detected in house flies (Musca domestica Linneaus) by staining with specific fluorescent antibody. The flies were collected within a swine confinement facility in which tge was enzootic.

Laboratory-reared flies were infected experimentally with tge virus and the virus was recovered from the insects for 72 hours after infection. The tge virus was identified both by the fluorescent antibody technique and by isolation in cell culture. The nature of plaque formation in cell monolayers inoculated with the virus passaged through flies changed from a large plaque (4 mm or greater in diameter) to a small plaque (1 mm in diameter) over the period. Large plaques were observed early after infection and were attributed to tge virus mechanically carried by the flies. Small plaques occurred 8 to 12 hours after infection and were considered to be produced by virus replicated in the dipterous cell.
Phenylbutazone kinetics and metabolite concentrations in the horse after five days of administration
Authors: Soma L. R. , Gallis D. E. , Davis W. L. , Cochran T. A. , Woodward C. B.
Published: February 2025

Phenylbutazone (pbz) was administered (8.8 mg/kg of body weight) every 24 hours for 5 consecutive days, orally for the first 4 days and iv on day 5. The half-life (t½) after this daily administration was 6.2 hours and the volume of distribution was 0.152 ± 0.014 L/kg; the bioavailability after oral administration was 91.8 ± 2.5%. The plasma concentration of pbz at experimental hour (eh) 24 (24 hours after the 1st oral dose) was 1.7 ± 0.39 µg/ml and increased to 4.2 ± 0.29 µg/ml at eh 48 (24 hours after the 2nd oral dose). Values at eh 72, 96, and 120 (24 hours after administration of oral doses 3 and 4, and dose 5, respectively) were 4.8 ± 0.62 µg/ml, 5.3 ± 0.84 µg/ml, and 4.3 ± 1.1 µg/ml, respectively. Significant increases (P < 0.05) were measured between eh 24 and 48 with no changes during the subsequent 3 days. Changes in the urinary concentrations of pbz were not seen over the 5-day dosing period. There were increases in the metabolites oxyphenbutazone and the α-alcohol during the 5-day dosing period. There was a delay in the appearance of α-alcohol in urine after oral and iv administration.
Acute experimentally induced aflatoxicosis in the weanling pony
Authors: Bortell R. , Asquith R. L. , Edds G. T. , Simpson C. F. , Aller W. W.
Published: February 2025

Nineteen weanling ponies and 1 adult pony were given a single oral dose of aflatoxin B1 (AFB1). Dosages were: 0, 0.5, 1, 2, 4, 5, 6, and 7.4 mg of AFB1/kg of body weight. Vital signs were monitored, and whole blood and serum collected for analysis of serum enzymes, prothrombin time, blood cell counts, and serum urea nitrogen. Ponies that died were examined for gross lesions, and tissues were collected for histopathologic examination and analysis of AFB1 and AFM1 residues.

Two of the 4 ponies given the 2 mg/kg dose and all ponies given the larger dosages died within 76 hours. Clinical signs included increased rectal temperature, faster heart and respiratory rates, abdominal straining, bloody feces, and tetanic convulsions. At necropsy, ponies that died of acute aflatoxicosis showed visceral petechiae and hepatic focal lesions. Histopathologic changes included severe hepatic necrosis, vacuolation, and bile duct hyperplasia. Aflatoxins B1 and M1 were recovered from liver, kidney, skeletal muscle, and gastrointestinal contents. One other pony given the 2 mg/kg dose died 32 days after dosing, and 1 control pony died after 70 days.

Continuous elevations in prothrombin time and serum aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transpeptidase levels were observed in ponies dosed at 4 mg/kg or more. Significant (P < 0.05) elevations in these values, which peaked 2 to 3 days after dosing, were seen in ponies given the 2 mg/kg dose. This group also had significant increases over controls in pcv and hemoglobin concentration 5 days after dosing.
Clinical, clinicopathologic, and pathologic alterations in acute monensin toxicosis in cattle
Authors: Van Vleet John F. , Amstutz Harold E. , Weirich Walter E. , Rebar Alan H. , Ferrans Victor J.
Published: February 2025

Twenty beef calves weighing approximately 180 kg were allotted to 3 groups. In group A, 6 calves were given 25 mg of mycelial monensin/kg of body weight orally and were evaluated at 1, 2, and 4 days for clinical, ecg, clinicopathologic, and pathologic alterations. In group B, 7 calves were given a single dose of monensin (40 mg/kg) and 5 were given a 2nd 40 mg/kg dose on day 7; calves were evaluated at days 1, 2, 4, 7, 8, 9, and 11. In group C, 2 calves served as controls.

Monensin-treated calves developed anorexia, diarrhea, and lethargy after day 1. One group B calf died on day 7 with lesions of congestive heart failure. Electrocardiographic abnormalities were not observed in group A calves; in group B, prolongation of Q-T and QRS intervals occurred from days 2 to 11 and first degree heart block was seen from days 7 to 11. Clinicopathologic alterations included: increased serum activities of aspartate aminotransferase and creatine kinase in group B calves after day 2; decreased serum K+, Na+, and Ca2+ concentrations in both groups, and postdosing occurrence of leukocytosis.

Calves were euthanatized sequentially and the lesions of monensin toxicosis were present in the heart, skeletal muscles, and rumen in groups A and B. Disseminated pale yellowish-brown areas of necrosis were present in the ventricular myocardium of 6 of 12 group B calves. Gross lesions were not present in the skeletal muscles or rumen. Microscopically, the myocardial and skeletal muscular lesions were characterized by sarcoplasmic vacuolation from mitochondrial swelling and lipid accumulation in calves killed after day 1 in groups A and B, and by myocardial necrosis with contraction bands, but without calcification, in group B calves killed by day 4. Acute rumenitis was present in groups A and B calves.

Myotoxic effects of monensin may be related to its action as an ionophore producing altered intracellular ion concentrations and initiating degeneration and necrosis in striated muscle fibers.
Histamine-induced suppressor macrophage inhibits fibroblast growth and wound healing
Authors: Kenyon Alan J. , Ramos L. , Michaels E. B.
Published: February 2025

To determine whether there is histamine-induced suppressor activity in macrophage-related functions other than in immunity, extracts and media from a macrophage cell line, RAW 264, were tested for suppressor effect on fibroplasia. The procedure consisted of priming confluent RAW 264 cells in culture with media or cellular extracts of washed mastocytes (P-815). The inoculum was removed from the RAW 264 cells by rinsing with fresh medium 24 hours later, and then with medium replacement and 3 more days of culture. The culture media or extracts of washed RAW 264 cells were tested for suppressor activity. The primed RAW 264 cells were lysed by 4 freezethaw cycles and cleared by centrifugation, and the resulting supernatant was tested on fibroblast (3T3) cell growth and wound healing in mice and for suppressor activity on T cells.

Replication of 3T3 cells, as quantitated by uptake of [3H]thymidine, was reduced 75% when “suppressor” material from RAW 264 cells was added to 3T3 cultures and not when media or extracts of unprimed RAW 264 cells were added. Tensiometric measurements of wound breaking strength (full-thickness incised wounds) were reduced 31% by day 4 and 47% by postsurgical day 7 when “suppressor” RAW 264 extracts were instilled into wounds. Leukocyte cultures stimulated with phytohemagglutinin had a reduced uptake of [3H]thymidine (suppressed 90% to 95%) when exposed to primed RAW 264 extracts, whereas kidney cell culture lines were unaffected. The data obtained indicated that mastocyte (histamine)-induced suppressor factors are present for fibroblast activity as well as T-cell function.
Pathogenicity of Campylobacter jejuni and Campylobacter coli strains in the pregnant guinea pig model
Authors: SultanDosa A. B. , Bryner J. H. , Foley J. W.
Published: February 2025

Pathogenicity of 17 Campylobacter isolates for pregnant guinea pigs was investigated. Of 14 isolates, 12 (86%) produced rates of abortion ranging from 13% to 87%. Two isolates did not produce abortion. Reference strains of C fetus subsp venerealis produced abortion in 60% to 87% and C fetus subsp fetus produced abortion in 60% of the guinea pigs. Inoculated organisms were recovered from uterus, blood, liver, kidney, spleen, and gallbladder of the guinea pigs at rates as high as 83% for 2 ovine isolates and as low as 13% for 2 bovine and 1 human isolates. Most isolations were from the uterus. Two avian isolates were not recovered. Within the C jejuni and C coli group, the ovine and the human isolates appear to be more pathogenic. Swine, bovine, and avian isolates were less pathogenic. Seemingly, the pregnant guinea pig was a suitable and practical model for evaluating the pathogenicity of Campylobacter organisms, regardless of their host of origin.
Horse red blood cells frozen with 20% (w/v) glycerol and stored at −150 C for five years
Authors: Valeri C. R. , Valeri D. A. , Gray A. , Contreras T. J. , Lindberg J. R.
Published: February 2025

When equine rbc were frozen with 20% (w/v) glycerol and stored at −150 C for as long as 5 years, there were no adverse effects on freeze-thaw or freeze-thaw-wash recovery or oxygen transport function. The manner in which the glycerol was added to, and removed from, the equine rbc was shown to be an important consideration in ensuring optimal freeze-thaw-wash recovery values.
Experimental infection of sheep by caprine arthritis-encephalitis virus and goats by progressive pneumonia virus
Authors: Banks Keith L. , Adams D. S. , McGuire T. C. , Carlson Jan
Published: February 2025

The lentiviruses, caprine arthritis-encephalitis virus (caev) and progressive pneumonia virus (ppv) of sheep, cause major diseases in their respective hosts; however, the infectivity of these viruses for closely related species has not been determined. Experiments were conducted to determine whether caev would infect sheep and whether ppv would infect goats.

Upon inoculation with caev, lambs developed a nonsuppurative arthritis and antibody to caev, and the virus was isolated up to 4 months later. Exposure of 3 lambs to caev-infected adult goats did not lead to demonstrable infection after 18 months. Young goats inoculated with ppv replicated the virus and developed arthritis and antiviral antibody. These results demonstrate that these distinctly different lentiviruses may infect and cause diseases in species other than their accustomed host. Presently used techniques may not be effective in differentiating which lentivirus is responsible for infection of sheep and goats. Our results also indicate that mixing sheep and goats may adversely influence attempts to eradicate lentiviruses from these species.
Indocyanine green clearance and ammonia tolerance in partially hepatectomized and hepatic devascularized, anesthetized dogs
Authors: Prasse Keith W. , Bjorling Dale E. , Holmes Robert A. , Cornelius Larry M.
Published: February 2025

SUMMARY AND CONCLUSIONS

Indocyanine green clearance and ammonia tolerance were measured in anesthetized dogs with 60% hepatectomy, 40% hepatectomy, portacaval shunt, and hepatic artery ligation. With a dose of 0.5 mg of indocyanine green/kg of body weight, plasma clearance of the dye was significantly (P < 0.001) delayed only in dogs with 60% hepatectomy. Ammonia tolerance was abnormal in dogs in this group, because after they were given a gastric challenge load of an ammonium salt, they had a 5-fold increase in plasma ammonia concentration, compared with a 2.5-fold increase in the control group. Before challenge loading, base-line plasma ammonia concentration was significantly (P < 0.05) increased within 5 minutes after surgical preparation of the portacaval shunt. After challenge loading the stomach with an ammonium salt, dogs with portacaval shunt had increased plasma ammonia concentration, but the amount was not significantly different from postchallenge-loading values in control dogs. Dogs with 40% hepatectomy and with hepatic artery ligation could not be differentiated from control dogs by indocyanine green clearance or by ammonia tolerance testing.

Abnormal tolerance to a challenge gastric load of an ammonium salt or delayed clearance of indocyanine green may indicate marked loss of functional hepatic mass, but normal tolerance or normal dye clearance may not exclude liver disease or dysfunction. Seemingly, base-line plasma ammonia concentration was a sensitive indicator of abnormal portal circulation. In dogs with clinical portasystemic shunt, the magnitude of increase in plasma ammonia concentration after challenge oral loading with an ammonium salt may not be greater than that of controls, until secondary hepatic atrophy reaches some critical level. At a dosage level of 0.5 mg of indocyanine green/kg, dye clearance in clinical portasystemic shunt dogs would not be expected to be abnormal until some critical degree of atrophy had occurred.
Hyaloid artery patency in neonatal Beagles
Authors: Duddy James A. , Powzaniuk Wolodymyr C. , Rubin Lionel F.
Published: February 2025

The patency of the hyaloid artery in neonatal Beagles was evaluated after liquid latex perfusion. As early as postpartum day 5, some pups had closure of the most distal branches of the vessels of the posterior lens tunica, but in these, many larger branches were open. Other pups at postpartum days 5 and 6 had substantially all of the blood vessels of the posterior tunica vasculosa lentis open. Few tunica vessels were patent in any pups beyond day 13, and none was patent after day 17. Persistent hyaloid remnants at the optic disk were evident in 3 of 16 pups 17 to 28 days old, but absent in the others.
System for enumerating and separating bovine lymphocytes, using coordinated En and Ea markers: Evaluation of lymph node lymphocytes
Authors: Hurley David John , Mastro Andrea M.
Published: February 2025

A procedure was developed for enumeration and separation of bovine lymph node T-lymphocyte sub-populations. An evaluation was made of T-lymphocyte rosetting with sheep erythrocytes treated with aminoethylisothiouronium bromide and neuraminidase (Ea and En) in RPMI and L-15 media. The effect of holding the lymphocytes in culture over a period of 7 days on the En and Ea markers was established. The optimal period of incubation at 0 C for isolation of the rosetting populations with respect to initial rosette formation, enrichment of the rosetting population in the recovered cells, viability after incubation, and recovery of the cells after the separation was determined. An estimate of the overlap of the Ea and En populations also was made from the separation data. We found that approximately 32% of the lymph node lymphocytes marked with En and Ea rosettes, 11% with only En, and 27% with only Ea.
Changes in penetrability of bovine papillary duct to endotoxin after milking
Authors: Schultze W. Donald , Bright Susan C.
Published: February 2025

The relative penetrability of bovine papillary ducts was assayed using frequency of inflammatory response to implantation of Escherichia coli endotoxin at a depth of 3 mm. Penetrability immediately after machine milking, compared with penetrability after delays of 10 to 480 minutes, indicated a decrease in frequency of penetrability to a minimum at 2 hours after milking, a decrease of about 75%. Four and 8 hours after milking, frequency of penetrability increased to about 55% of that measured immediately after milking.
Experimental infection of lambs with ovine adenovirus isolate RTS-151: Lesions
Authors: Cutlip R. C. , Lehmkuhl H. D.
Published: February 2025

Young lambs, inoculated with ovine adenovirus isolate RTS-151, were killed sequentially (to postinoculation day 21), and their morphologic lesions were studied. Lesions were found only in the respiratory tract and were most severe in the terminal airways. Many cells of the respiratory epithelium had severe cytomegaly and karyomegaly with intranuclear inclusions. Desquamation of affected cells was accompanied by hyperplasia of airway and alveolar epithelium and by accumulation of necrotic cellular debris and neutrophils in terminal airways and alveoli. Virus replicated in the nucleus of enlarged epithelial cells in the airways, but not in alveolar epithelium. Intranuclear inclusions representing viral replication progressed from clumps of finely granular material without virions to a granular material with virions and finally to a dense inclusion with numerous virions.
Serologic diagnosis of infectious cyclic thrombocytopenia in dogs using an indirect fluorescent antibody test
Authors: French Tracy W. , Harvey John W.
Published: February 2025

An indirect fluorescent antibody test was used for detection of serum antibodies to the platelet-specific rickettsial organism that is the causative agent of infectious cyclic thrombocytopenia (ict) in dogs. The test converted from negative to positive in 7 of 7 experimentally inoculated dogs. One of 2 attempts to recover the rickettsial agent of ict from naturally occurring seropositive dogs, by blood inoculation of experimental dogs, was successful. Seemingly, the test did not detect antibodies to Ehrlichia canis, nor did a similar test, using E canis antigen slides, detect antibodies to the rickettsial agent of ict. The rickettsial agent of ict has been classified tentatively as E platys.

When applied to sera from a group of healthy random-source dogs, the test revealed a relatively low (5%) occurrence of positive reactions. A higher occurrence of positive reactions (35%) was noticed in sera from a group of thrombocytopenic dogs from the University of Florida. A majority of these positive sera were also positive for antibodies to E canis. The highest occurrence of positive reactions was found (> 50%) in E canis-positive sera from dogs at the University of Florida, as well as from dogs from 9 other states.
Effects of propranolol on thyroid function in the dog
Authors: Center S. A. , Mitchell J. , Nachreiner R. F. , Concannon P. W. , Reimers T. J.
Published: February 2025

The effect of propranolol on thyroid function was evaluated in 6 mature euthyroid Beagles. Propranolol was administered orally in doses of 20 mg given 3 times daily for 2 weeks and then increased to 40 mg given 3 times daily for an additional 2 weeks. Six age- and sex-matched, euthyroid Beagles served as controls. Serum base-line concentrations of tetraiodothyronine (T4), triiodothyronine (T3), and reverse triiodothyronine (rT3) were measured before propranolol administration and at weekly intervals thereafter. Thyroid response to 5 IU of aqueous thyroid stimulating hormone administered iv was monitored before propranolol administration and at the 2- and 4-week treatment intervals. The T4, T3, and rT3 concentrations were measured by radioimmunoassay.

There were no significant differences in base-line or postthyroid stimulating hormone serum concentrations of T4, T3, or rT3 in any individual or between the treatment or control groups at any treatment interval (P > 0.05). Seemingly, the therapeutic use of propranolol in euthyroid dogs should not alter thyroid hormone metabolism.
Validation of radioimmunoassays to measure prostaglandins F2α and E2 in canine endometrium and plasma
Authors: Olson P. N. , Bowen R. A. , Behrendt M. D. , Olson J. D. , Nett T. M.
Published: February 2025

Equilibrium, double-antibody radioimmunoassay (ria) procedures were validated to measure concentrations of prostaglandin (pg) F2α and E2 in canine plasma and endometrium. The procedure for measuring pgf2α or pge2 used [125I]pgf2α or [3H]pge2, respectively, as radiolabeled antigens. Specificity was demonstrated by determining the relative potency of selected pg. Relative potencies were calculated by dividing the mass of pgf2α or pge2 producing 50% inhibition of maximum bound tubes (Bo) by the quantity of test pg producing 50% inhibition in the same assay. Only pgf1α and pge1 had relative potencies of > 1.0% in the pgf2α and pge2 ria, respectively. To assess the accuracy of the 2 assay systems, known amounts of authentic hormone were added to plasma, tissue, or 0.05M phosphate-buffered saline solution containing 0.1% gelatin (gel-pbss). When increasing amounts of pgf2α or pge2 were added to plasma, tissue, or gel-pbss, concentrations of pg assayed from extracted or extracted plus chromatographed samples were similar. Additionally, pgf1α or pge1 was not detected in canine plasma or tissue; therefore, extraction was the only purification needed before analysis of pgf2α or pge2.

The intra-assay precision of 10 assay replicates for a low (70% Bo) and high (27% Bo) sample was 16.0% and 6.7% (coefficient of variation), respectively, for the pgf2α assay. The intra-assay precision of 3 assay replicates for a low (80% Bo) and high (32% Bo) sample was 7.6% and 4.4%, respectively, for the pge2 assay. Sensitivities of the pgf2α and pge2 assays were 52 and 4 pg/tube, respectively. Plasma and tissue samples containing varying pgf2α and pge2 concentrations were assayed at different volumes to determine the ability to measure pg from different parts of the standard curve (ie, determine parallelism). Concentrations of pg assayed in 200-, 100-, or 50-μl aliquote were not different (P > 0.05).

These ria should enable quantitation of pgf2α and pge2 in canine plasma and endometrium to determine whether pgf2α or pge2 are important physiologic regulators of luteal function in the nonpregnant and/or pregnant bitch.
Response of great horned owls given the optical isomers of ketamine
Authors: Redig Patrick T. , Larson Alice A. , Duke Gary E.
Published: February 2025

The relative anesthetic effects of the 2 purified isomers and the racemic mixture of ketamine were compared in 6 great horned owls (Bubo virginianus), a species in which racemic ketamine is poorly tolerated. Other investigators have reported that the l(−) form is only a 3rd as potent as the d(+) form with respect to analgesic action in mammals. Accordingly, the racemic and the – forms were given at 2 × and 3 ×, respectively, the dose of the + form in an attempt to achieve a potentially equivalent state of anesthesia. At these dose levels, there was no difference observed in the average duration of anesthesia with the 3 ketamine preparations. The - isomer yielded a poorer anesthetic response characterized by inadequate muscle relaxation, cardiac arrhythmias, and marked excitatory behavior during recovery. With the dosages used, the + form and the racemate were comparable in degree of muscle relaxation produced. The + form yielded smoother inductions and less cardiac arrhythmia than did the racemate.
Cervical vertebral interbody fusion in the horse: A comparative study of bovine xenografts and autografts supported by stainless steel baskets
Authors: DeBowes R.M. , Grant B. D. , Bagby G. W. , Gallina A. M. , Sande R. D. , Ratzlaff M. H.
Published: February 2025

A modified form of the Cloward technique for anterior cervical fusion in human beings was used in the application of different grafts for evaluation of their effectiveness in stabilizing equine cervical vertebrae. Results of bovine xenograft implants in 8 horses were compared with results of stainless steel baskets (ssb) packed with cancellous autogenous bone in 8 horses. Graft material was incorporated in all cases. Evidence of graft rejection was not present. Both forms of implants decreased the mobility of the intervertebral space in which they were implanted. A fibrous connective tissue union was prevalent after xenograft implantation. Osseous union was prevalent after implantation of the ssb. Reduction in range of motion was greatest at those sites with the ssb.
Hematologic and coagulation abnormalities in acute bovine sarcocystosis
Authors: Frelier P. F. , Lewis R. M.
Published: February 2025

Calves inoculated with Sarcocystis cruzi sporocysts developed severe anemia 4 weeks later. The anemic crisis was paralleled by a hyperbilirubinemia, with up to 88% of the increased total bilirubin attributed to indirect reacting bilirubin. The anemia was characterized as normocytic and normochromic. In a few instances, according to Coombs's tests (antiglobulin test) and erytrocyte eluates from infected calves, immunoglobulin G was associated with the rbc membrane. In the histopathologic examinations of tissues from calves dying during the anemic crisis, there was deposition of iron in the splenic red pulp. The hematologic studies supported the claim that the anemia in acute bovine sarcocystosis is an extravascular hemolytic event, probably with an immunologic basis.

In the coagulation studies, consumption coagulopathy consistent with disseminated intravascular coagulation was seen to occur during acute sarcocystosis. At 4 weeks after inoculations were done, there were prolongations of activated partial thromboplastin and 1-stage prothrombin times and decreased functional fibrinogen concentration, and thrombocytopenia, although increase of fibrinogen-fibrin degradation products were not demonstrable. These findings indicate that endothelial parasitism by schizonts of S cruzi may cause endothelial damage, resulting in coagulation abnormalities that include disseminated intravascular coagulation.
Monoclonal antibody-purified antigen for the immunodiagnosis of trichinosis
Authors: Gamble H. R. , Graham C. E.
Published: February 2025

Monoclonal antibodies generated from spleen cells of Balb/cJ mice infected with Trichinella spiralis reacted with antigenic determinants present in some other common swine parasites, especially Trichuris suis. An antigenic determinant unique to T spiralis was recognized by one immunoglobulin M monoclonal antibody (7C2C5); this determinant was found on larval T spiralis proteins with molecular weights of 53,000, 49,000, and 45,000. These proteins were components of in vitro-derived worm excretory-secretory products. Immunoperoxidase staining techniques and reactions of the monoclonal antibody with living parasites indicated that the source of the antigen was the stichocyte. Two of the proteins (53,000 and 49,000 molecular weight) possessing this determinant were isolated by monoclonal antibody-affinity chromatography, using hybridoma 7C2C5. When used in a serologic enzyme-linked immunosorbent assay, the affinity-isolated antigen was able to completely eliminate false-positive reactions with serum from healthy swine and to detect all pigs infected with T spiralis.
Heterogeneity of contagious ecthyma virus isolates
Authors: Buddle Bryce M. , Dellers Robert W. , Schurig Gerhardt G.
Published: February 2025

Results of cross-neutralization tests of 4 isolates of contagious ecthyma (ce) virus and their antisera indicated that the isolates were neutralized to various degrees by the ce virus antisera. Cross-reactions among isolates were unilateral, but not bilateral, and therefore grouping of ce virus isolates by neutralization tests was not possible to obtain.

Structural analysis of polypeptides from 11 isolates of ce virus by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the profiles obtained were similar to one another, except for differences observed in the molecular weight region of 37,000 to 44,000. On the basis of these differences, the isolates could be classified into 4 groups. The polypeptides which varied among the different isolates were shown to be in the surface component of the virion and appeared to be components of the surface tubules. Unilateral cross-reactions detected in cross-neutralization tests were found to correlate with the 37,000 to 44,000 dalton polypeptide grouping of the isolates.