bluuebunny/crossref_metadata_2025 huggingface dataset:
Viral matrix inclusion bodies in myocardium of lymphoid leukosis virus-infected chickens
Authors: Gilka F. , Spencer J. L.
Published: February 2025

Chicken embryos and healthy adult chickens naturally infected with lymphoid leukosis virus were used to investigate viral inclusion bodies in myocardial cells by light and electron microscopies and by immunocytochemical technique. Intracytoplasmic viral matrix inclusion bodies frequently appeared in the myocardium of adult chickens, but not in that of embryos. In light microscopic preparations, inclusions were irregularly distributed, were basophilic, and contained ribonucleic acid. Ultrastructurally, inclusions in myocardial cells were in areas containing numerous interstitial C-type particles. Early inclusions were composed of clusters of ribosomes associated with sarcoplasmic tubules; spherical bodies developed among these ribosomes. Mature inclusions were composed of numerous spherical bodies (50 to 75 nm) with interspersed ribosomes and of ribosomes clustered at the periphery. Inclusions were not membrane-enclosed. Occasionally, spherical bodies were in paracrystalline arrays. Multiple budding occurred on cell membranes adjacent to matrix inclusions. The viral group-specific protein, p27, was demonstrated by the peroxidase-antiperoxidase method and by the protein A-gold method in the spherical bodies, in nucleoids of mature virus particles, and among ribosomes of inclusions. The results indicate that the matrix inclusions were the result of lymphoid leukosis virus infection and were the product of viral protein synthesis on ribosomes.
Bovine neutrophils treated with chemotactic agents: Morphologic changes
Authors: Forsell J. H. , Kateley J. R. , Smith C. W.
Published: February 2025

Neutrophils were isolated from the peripheral blood of cattle. After the neutrophils were incubated with zymosan-activated serum, the neutrophils changed from spherical to a bipolar shape. Ninety percent of the neutrophils became bipolar in 5 to 10 minutes. Bacterial cell filtrate and casein also induced bipolar shape changes in neutrophils, but N-formyl-l-methionyl-l-leucinyl-l-phenylalanine did not. The neutrophil-shape-change response was a rapid in vitro assay to evaluate early chemotactic events.
Efficacy of furosemide in the treatment of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses
Authors: Pascoe John R. , McCabe Anne E. , Franti Charles E. , Arthur Rick M.
Published: February 2025

The repeatability of endoscopic observations of exercise-induced pulmonary hemorrhage (eiph) and the efficacy of furosemide as a prophylactic treatment of horses with eiph were studied in Thoroughbred race horses after consecutive breezes (at or near maximum speed, approx 16 m/s). Of 56 horses examined ≥ 2 times, 21 (38%) had identical eiph scores, whereas 26 (46%) and 9 (16%) had scores that differed by ≥ 1 grade. In 56 nontreated horses, there was good agreement between 2 consecutive observations (K = 0.59, Z = 4.54, P < 0.001). Similar comparisons after placebo (saline solution) treatment of 21 horses yielded fair to good agreement, whereas poorer agreement was seen after furosemide treatment of 23 horses. Comparison of average and maximum eiph scores of 44 horses with a minimum of 4 observations (2 nontreated, 1 saline-treated, and 1 furosemide-treated) indicated that although furosemide did not stop eiph, it did reduce the eiph score in 28 (64%) horses.
Swine trichinosis in New England slaughterhouses
Authors: Schad Gerhard A. , Leiby David A. , Duffy Charles H. , Murrell K. Darwin
Published: February 2025

Diaphragms of 5,315 slaughter hogs from the New England states were examined for Trichinella spiralis infection between June 22 and Dec 22, 1983. Thirty-nine hogs (0.73%) were infected. The infections were light, none exceeding 30 larvae/g of tissue, with an arithmetic mean of 4.7 larvae/g. Infected hogs originated from 5 of 6 New England states. The widespread occurrence of porcine trichinosis in New England indicates that the small or part-time hog farming operations frequently found in this region may be especially vulnerable to the introduction and maintenance of the parasite.
Effects of multiple intramuscular injections and doses of dexamethasone on plasma cortisol concentrations and adrenal responses to ACTH in horses
Authors: MacHarg M. A. , Bottoms G. D. , Carter G. K. , Johnson M. A.
Published: February 2025

Adrenocortical function was assessed in horses given multiple im doses of dexamethasone to determine the duration of adrenocortical suppression and insufficiency caused by 2 commonly used dosages of dexamethasone (0.044 and 0.088 mg/kg of body weight). Dexamethasone was administered at 5-day intervals for a total of 6 injections. Daily blood samples were collected. The plasma was frozen and later assayed for cortisol. An ACTH response test was determined 2 days before the first injection of dexamethasone and again 8 days after the last dexamethasone injection. Maximum suppression of plasma cortisol was observed in horses given both dosages of dexamethasone (0.044 and 0.088 mg/kg). Plasma cortisol concentrations returned to base-line values in all horses by 4 days after dexamethasone injection. Normal ACTH responses observed after 6 dexamethasone injections given at 5-day intervals indicated that measurable adrenal atrophy did not develop under the conditions of this study.
Enzyme immunoassay for surveillance of Q fever
Authors: Behymer D. E. , Ruppanner R. , Brooks D. , Williams J. C. , Franti C. E.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was developed to monitor antibodies against Coxiella burnetii among animal populations used in research and teaching facilities. Various antigenic components of C burnetii prepared from phase I and phase II whole cells and commercially available antigens were evaluated. A trichloroacetic acid extract was selected for routine use. There was a linear relationship between the transformed absorbance readings of the elisa results and microagglutination (ma) titers. Comparison between positive or negative results of the ma test and elisa gave 98.6% concordance. Using the ma test as the standard, elisa results were 97.8% sensitive and 100% specific. The efficacy of elisa was evaluated by testing ruminants with known histories of C burnetii infection. Antibody prevalence was 0 in 117 sheep with no history of C burnetii infection, 22% in 145 naturally infected sheep used for research, and 53% in 115 sheep used for vaccine field trials. Forty-eight percent of 120 dairy cows and 52% of 79 goats from endemically infected herds were seropositive. These results indicate that elisa should be the test of choice for mass screening and surveillance of animals when Q fever is a suspected biohazard.
Seroepidemiologic survey for antibodies to selected viruses in the respiratory tract of lambs
Authors: Lehmkuhl Howard D. , Cutlip Randall C. , Bolin Steven R. , Brogden Kim A.
Published: February 2025

A serologic study was conducted to determine the prevalence of antibodies to, and infection rate of, Mastad-enouirus ovi 5, M ovi 6, parainfluenza-3 (pi-3) virus, bovine herpesvirus-1 (bhv-1), respiratory syncytial virus (rsv), bovine viral diarrhea (bvd) virus, and ovine progressive pneumonia (opp) virus in lambs at a ram lamb growth-rate test station. For 2 consecutive years, serum samples were prepared from blood collected from 1- to 2-month-old ram lambs as they entered the test station (1st sample) and again 2 months later (2nd sample). The 1st year, 59 producers submitted 237 lambs; the 2nd year, 65 producers submitted 253 lambs. Microtitration serum virus-neutralization tests were used to determine antibody titers for M ovi 5, M ovi 6, pi-3 virus, bhv-1, and bvd virus. Antibodies to rsv and opp virus were determined, using indirect hemagglutination and agar-gel immunodiffusion, respectively. Based on results of the 1st blood samples collected, the mean prevalence for both years was as follows: 95% of the lambs were seropositive for M ovi 5; 87.2% for pi-3 virus; 84.5% for rsv; 41.7% for M ovi 6; 8.7% for bvd virus; 5.4% for bhv-1; and 3.3% for opp virus. Based on the 2-year mean, M ovi 6 had the highest infection rate (207 of 484 [42.8%]) as determined by the number of lambs evaluated having a ≥ 4-fold increase in serum antibody titer from the 1st to the 2nd sampling. Infection rates of the other viruses were: 31.0% for M ovi 5; 15.3% for pl-3 virus; 5.6% for rsv; 0.6%. for bvd virus; and 0.4% for bhv-1. One lamb became seropositive for OPP virus the 2nd year.
Identification of antigens of two isolates of Anaplasma marginale, using a western blot technique
Authors: Adams John H. , Smith Ronald D. , Kuhlenschmidt M. S.
Published: February 2025

Antigens of the Illinois (IAM) and Florida (FAM) isolates of Anaplasma marginale were analyzed, using the western blot technique and antiserum from A marginale-infected calves. Crude antigens were prepared from the parasitemic blood of each. Antiserum was collected after the primary and recrudescent parasitemias. Antigens were separated, using sodium dodecyl sulfate Polyacrylamide gel electrophoresis. Antigens were then transferred onto nitrocellulose membranes and exposed to test sera. Antibodies attached to the membrane-bound antigens were detected, using an avidin/biotin peroxidase assay and biotinylated rabbit anti-goat immunoglobulin G. Antigens detected were of a high molecular weight group (108 to 91 kilodaltons [kd]) or of a low molecular weight group (47 to 27 kd). The IAM antigens were 100 kd, 96 kd, 47 kd, 38 to 43 kd, and 27 kd; these antigens were detected, using anti-IAM and anti-FAM antibodies, but the anti-FAM antibodies had a strong reaction to only the 100-kd and 38- to 43-kd antigens of IAM. The FAM antigens were 108 kd, 91 kid, 47 kd, 38 to 43 kd, and 27 kd; these antigens were detected, using anti-FAM antibodies and, except the 91 kd antigen, anti-IAM antibodies. Because the 91-kd antigen was detected only in the FAM antigen and detected only by sera from FAM-infected calves, this isolate-specific antigen may be associated with the ability of FAM to induce disease in an IAM-immune animal. Sheep anti-A ovis antibodies reacted only to the 38- to 43-kd antigens of each isolate, indicating that these antigens may be genus-specific. The high molecular weight antigens 108 kd, 100 kd, and 96 kd may be species-specific because they were detected when using their respective heterologous antisera but were not detected when using the anti-A ovis antisera. These genus-, species-, and isolate-specific antigens may be a basis for strain differentiation of Anaplasma isolates.
Evaluation of three formulations of fenbendazole (10% suspension, 0.5% pellets, and 20% premix) against nematode infections in cattle
Authors: Blagburn Byron L. , Hanrahan Lynn A. , Hendrix Charles M. , Lindsay David S.
Published: February 2025

Anthelmintic efficacies of 3 formulations of fenbendazole were evaluated in cattle naturally parasitized with nematodes: a 10% oral suspension, 0.5% pellets as a top dressing on feed, and a 20% premix. All formulations of fenbendazole were > 99% effective in removing adults of Haemonchus contortus, Ostertagia spp, Cooperia spp, and Oesophagostomum radiatum. Fenbendazole was > 96% effective in removing adults of Strongyloides papillosum and > 85% effective in the removal of Trichuris sp. Fenbendazole was > 96% effective against immature nematodes, which were thought to be primarily Cooperia spp. Adverse reactions were not observed in calves treated with the 3 formulations of fenbendazole.
Acute arthritis in caprine arthritis-encephalitis virus challenge exposure of vaccinated or persistently infected goats
Authors: McGuire Travis C. , Adams D. Scott , Johnson Gayle C. , Klevjer-Anderson Paula , Barbee David D. , Gorham John R.
Published: February 2025

Goats vaccinated with inactivated caprine arthritis-encephalitis virus (CAEV) developed more severe arthritis after infectious CAEV challenge exposure than did goats vaccinated with tissue culture medium. Arthritis also developed more rapidly in the group vaccinated with inactivated virus.

In another experiment, goats with persistent CAEV infection developed acute arthritis after at least 2 injections of infectious CAEV at monthly intervals. In this experiment, the control group consisted of goats with persistent CAEV that were given tissue culture medium. Seemingly, the immune response to CAEV is an important cause of the CAEV-induced arthritis.
Enzyme-linked immunosorbent assay to detect subgroup-specific antibodies to avian leukosis viruses
Authors: Mizuno Yoshio , Itohara Shigeyoshi
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was developed to detect antibodies against avian leukosis viruses (alv), using antigens extracted from Rous-associated virus-inoculated chicken embryo fibroblast (cef) cells by Nonidet P-40 treatments. The antigens reacted strongly to sera of chickens immunized with antigenically homologous viruses, but weakly to those of chickens immunized with heterologous viruses. Antigens extracted from non-inoculated cef cells by the same procedures did not react to either of the immune sera. Normal control sera did not react to any of the antigens. Reactivities of immune sera were decreased markedly by the sera adsorbing with homologous Rous-associated virus-inoculated cef cells, but not with heterologous cef cells. The elisa-specific optimal doses (the differences between the optimal doses with antigens from alv-inoculated and noninoculated cef cells) were correlated strongly with the virus-neutralization titers (r = 0.876, P < 0.01). Examination of the antibody response from alv-inoculated chickens revealed that elisa detected antibodies at the same time or several weeks earlier than did the virus-neutralization test.
Conduction velocities and myelinated fiber diameter spectra of the infraorbital and palpebral nerves of the dog
Authors: Whalen L. R. , Carsten R. E.
Published: February 2025

Maximum conduction velocities of compound-action potentials of the infraorbital (ion) and palpebral (pn) nerves were determined by averaging potentials evoked and recorded through subcutaneous needle electrodes. The specificity of the stimulating and recording sites was verified by recording before and after cutting the nerves. Conduction times for orthodromically and antidromically conducted potentials of the ion were essentially the same. The unipolarly recorded antidromic compound-action potentials of the ion were of higher peak-to-peak amplitude and were more reliably recorded than were the bipolarly recorded orthodromic action potentials. Areas of cutaneous innervation were not found for the pn. Neuromuscular blockade eliminated the volume-conducted muscle action potentials that were recorded after pn stimulation, allowing triphasic nerve action potentials to be recorded unobscured. Mean conduction velocities were: ion = 83.9 ± 3.5 m/s; pn = 56.4 ± 2.8 m/s. Distributions of the external diameters of myelinated fibers within the ion and the pn were determined.
Age and dosage dependency in the plasma disposition and the renal clearance of sulfamethazine and its N4-acetyl and hydroxy metabolites in calves and cows
Authors: Nouws Jacques F. M. , Vree Tom B. , Baakman Margriet , Driessens Freek , Breukink Henk J. , Mevius Dick
Published: February 2025

Plasma disposition, protein binding, urinary recovery, and renal clearance of sulfamethazine (smz), its N4-acetylsulfamethazine (N4-smz), and its 2 hydroxy metabolites—6-hydroxymethylsulfamethazine (sch2oh) and 5-hydroxysulfamethazine (soh)—and the glucuronide of the latter were studied in 7 cows and 7 calves to determine the relationship between these values and the age of the animal and dosage applied. A capacity-limited hydroxylation of smz into sch2oh was observed in cows and calves given dosages of 100 to 200 mg/kg. A biphasic smz elimination curve and steady state in sch2oh plasma concentration (6 to 15 μg/ml) were observed. The N4-smz plasma concentration-time curve was parallel to that of smz at the dosages and in all animals.

The total body clearance and the cumulative urinary recovery (expressed as percentage of the dose) for smz and its metabolites depended on drug dosage and age of the animals. At dosages of smz < 25 mg/kg, the main metabolite in the urine of calves and cows was sch2oh (23% to 55.2%), whereas in calves given a larger dosage (100 mg/kg), the N4-smz and soh percentages increased.

The plasma protein binding of smz and its metabolites depended on the smz plasma concentration. Hydroxylation lowered the protein binding (from 75-80%) to 50%.

The renal clearance of smz was dependent on urine flow in all animals. The renal clearance of the sch2oh metabolite was 2 to 3 times greater than the creatinine clearance value; thus, this compound was excreted by glomerular filtration and partly by tubular secretion.

Both N4-smz and soh were predominantly excreted by tubular secretion; at dosages of smz of 100 to 200 mg/kg, and N4-smz clearance was diminished. Intravenous administration of N4-smz to a calf resulted in deacetylation and a subsequent hydroxylation of the formed smz into the 2 hydroxy metabolites.

It was concluded that the elimination half-life of smz in ruminants depended mainly on the extent of the metabolism, which was dose related, and on the renal clearance of its metabolites.
Unconventional aqueous humor outflow of microspheres perfused into the equine eye
Authors: Smith P. J. , Samuelson D. A. , Brooks D. E. , Whitley R. D.
Published: February 2025

Normal drainage of aqueous humor from the anterior chamber of the equine eye occurred through conventional and unconventional routes. To determine the degree of uveoscleral outflow in the pony, 1- and 3-μm (diam) microspheres were perfused through the anterior chamber for 60 and 90 minutes. Two eyes were treated with pilocarpine before perfusion of spheres to observe any effect on outflow. Presence of spheres was detected by scanning electron microscopy and verified by light microcoopy.

By 60 minutes of the perfusion 1- and 3-μm spheres thoroughly infiltrated the anterior uveal trabecular meshwork. The 3-μm spheres were notably excluded from the corneoscleral trabecular meshwork, whereas the 1-μm spheres packed into the corneoscleral trabecular meshwork and mixed with the angular aqueous plexus and intrascleral plexus vessels. After 90 minutes, 1- and 3-μm spheres penetrated the prominent supraciliary space and mixed with the suprachoroidea of the midchoroid. The 1-μm spheres infiltrated tissues more extensively than did the 3-μm spheres, packing into the anterior meshwork and supraciliary space and also moving as far posterior as the suprachoroidea of the peripapillary retina.

Spheres also entered the iris, mostly at the root. Several 3-μm spheres moved into the interstitial spaces around axon bundles and vessels in the iris. The 1-μm spheres packed into these spaces in the iris root and were observed in the lumens of iris vessels. Single 1-μm spheres were observed in the lumens of choroidal vessels posteriorly. The present study supported evidence for uveoscleral and uveovortex flow in the horse and indicated that it may be more extensive than that in other species investigated (ie, the dog).
Scanning electron microscopic studies of megakaryocytes and platelet formation in the dog and rat
Authors: Handagama Prem , Jain N. C. , Kono C. S. , Feldman B. F.
Published: February 2025

Megakaryocyte morphology and platelet formation in canine and murine bone marrows were studied by scanning electron microscopy. In situ-fixed bone marrow preparations and cell suspensions of bone marrow provided complementary information for the 2 species (dogs and rats).

Cylindrical processes (proplatelets) of variable length and thickness, originating from the megakaryocyte surface, were in the larger marrow sinusoids and the central vein. Regional constrictions along the length of proplatelets, particularly near their apical region, and the presence of fragments of such processes supported the concept of platelet formation through segmentation of proplatelets.

Megakaryocytes presented varied morphology. Surface features resembling platelets were observed on megakaryocytes, indicating that platelets may have been released through surface budding.

In conclusion, megakaryocytes formed long proplatelet processes that actively migrated to venous sinusoids to release platelets by fragmentation. Scanning electron microscopy analysis revealed a complex and variable megakaryocyte surface topography. The platelet-like structures on megakaryocyte surfaces may represent platelet release by a budding mechanism. The similarity between murine platelet release and canine platelet release demonstrates that data from rodent models may be applicable to nonrodents.
Infectivity of three Anaplasma marginale isolates for Dermacentor andersoni
Authors: Wickwire Kathie B. , Kocan Katherine M. , Barron Selwyn J. , Ewing S. A. , Smith Ronald D. , Hair Jakie A.
Published: February 2025

Three isolates of Anaplasma marginale—Virginia (vam), Illinois (iam), and Florida (fam)—were compared for infectivity for Dermacentor andersoni. The isolates were selected, in part, because of a tail-like appendage that has been demonstrated in the vam and iam, but not in the fam. Ticks were exposed to the isolates as nymphs either naturally by feeding on a calf with anaplasmosis or artificially by percutaneous inoculation with infected bovine erythrocytes. They were examined for infectivity after molting to the adult stage (i) by determining their capability to transmit the disease to susceptible calves and (ii) by demonstrating colonies in tick gut sections. Only those ticks exposed to the vam proved to be infected with A marginale; ticks naturally exposed and those artificially infected with this isolate transmitted the disease to susceptible calves. Colonies of A marginale were observed only in gut tissues of ticks naturally infected with vam. The iam (appendage present) and fam (appendage absent) could not be found in ticks exposed by either method, indicating that factors other than the presence of inclusion appendages may be involved in infection of ticks by A marginale.
Demonstration of Pasteurella-specific immunoglobulin E in bovine serum
Authors: Gershwin Laurel J. , Friebertshauser Kathleen
Published: February 2025

On the basis of recent observations that immunoglobulin (Ig) E antibodies specific for bacterial antigens occur in the serum of persons with chronic respiratory tract disease, we used bovine ϵ chain-specific antiserum to investigate the possibility that IgE antibodies are induced in cattle infected with Pasteurella. Using enzyme-linked immunosorbent assay and Western blotting techniques, we studied bovine sera to detect and quantitate the presence of IgE antibodies specific for antigens of Pasteurella. Immunoglobulin E antibodies reactive with whole formalinized P haemolytica, potassium thiocyanate, and saline solution extracts were detected in serum of calves with bronchopneumonia, feedlot steers with interstitial pneumonia, as well as nonaffected penmates, and adult dairy cows.

The role of parenteral vaccination in eliciting an IgE response was examined in healthy calves; vaccination with a Pasteurella bacterin failed to induce an IgE response. Adsorption studies were done to demonstrate the specificity of the antibodies for Pasteurella. Enzyme-linked immunosorbent assay absorbance values were significantly decreased by adsorption with P haemolytica, whereas adsorption with other gram-negative bacteria only moderately decreased serum absorbance values.

To begin identification of the antigen(s) to which the IgE binds, Western blotting of P haemolytica extract with sera from calves with bronchopneumonia was done. A dense band of protein (˜60,000 daltons) reacted strongly with IgE in the highest titer sera. These results indicate that Pasteurella-specific IgE antibodies are not readily induced by parenteral vaccination, but can be found in serum of some cattle, possibly induced by existing or previous infection. Persistence ofP haemolytica-specific IgE in serum may reflect environmental exposure of cattle after resolution of acute pneumonia.
An evaluation of agglutination and coagglutination techniques for serotyping of Haemophilus pleuropneumoniae isolates
Authors: Mittal K. R. , Higgins R. , Lariviere S.
Published: February 2025

A comparative evaluation of rapid slide agglutination, tube agglutination, 2-mercaptoethanol tube agglutination, and coagglutination tests was made for serotyping isolates of Haemophilus pleuropneumoniae. The results indicated that a majority of the isolates could be serotyped by any of these tests. But, it was not uncommon to find isolates which were inagglutinable or poorly agglutinable in homologous sera. Heat treatment of whole-cell suspensions of such isolates was essential to unmask the serotype-specific antigenic determinants; however, in the process of heat treatment, cross-reactive common antigens of minor nature were also exposed. The antibodies involved in such cross-reactions were mainly of immunoglobulin M type, because the cross-reactivities were completely abolished in coagglutination and 2-mercaptoethanol agglutination tests. Thus, both these tests were satisfactory for serotyping inagglutinable mucoid strains. For serotyping strains which were either polyagglutinating or autoagglutinating, agglutination tests could not be used, but the coagglutination test proved to be satisfactory. The coagglutination test was serotype-specific, sensitive, simple, rapid, reproducible, and easier to read and interpret than rapid slide or tube agglutination tests. This test could be used to serotype mucoid, smooth, or rough isolates.
Relationships of bovine leukemia virus prevalence in dairy herds and density of dairy cattle to human lymphocytic leukemia
Authors: Donham Kelley J. , Burmeister Leon F. , VanLier Stephanie F. , Greiner Timothy C.
Published: February 2025

A case-control study was conducted to examine possible relationships between human acute lymphoid leukemia and exposure to dairy cattle and drinking of raw milk. Two hundred twenty-three persons with acute lymphoid leukemia, diagnosed during the years 1969 to 1971 and 1973 to 1980 from the 87 most rural Iowa counties, were accessed from case records at the Iowa State Health Registry for participation in the present study.

Each person and 2 matched controls were interviewed for history of residence, exposure to dairy cattle, and consumption of nonpasteurized dairy products.

Two types of comparisons between affected persons and controls were done: (1) the prevalence of bovine leukemia virus infection (as measured by serologic study) in dairy herds with which the affected persons and controls had either occupational contact or from which they had consumed raw milk and (2) the density of dairy cattle in the townships where affected persons and controls lived.

The bovine leukemia virus infection prevalence in dairy herds with which affected persons had contact was 20%, whereas the infection prevalence in the herds with which the controls had contact was 38%.

The density of dairy cows in townships where affected persons resided was generally less than that in townships where controls resided. However, there was one exception; the density of dairy cows at 20 years before diagnosis was higher (589) in townships where affected adult female persons resided, compared with that in townships where controls resided (567).
Clinical chemistry reference values in two breeds of swine and their changes during percutaneous exposure to soman
Authors: James John T. , Manthei James H. , Goodwin Bradford S. , Heitkamp Dale , Liebenberg Stanley P.
Published: February 2025

Clinical chemistry reference values in blood from 48 nonfasting Chester White/Yorkshire and 48 Hanford Miniature swine were determined. Subsequently, 40 animals of each breed were restrained in a cloth sling and fasted for 24 hours while exposed percutaneously to pinacolyl methylphosphonofluoridate (soman). The range of dosages for the Hanford Miniature swine was 2.0 to 15.8 mg/kg, and for the Chester White/Yorkshire swine, the range was 4.0 to 25.0 mg/kg. Shamexposed groups, consisting of 8 animals of each breed, were treated in an identical manner, except no anticholinesterase agent was administered. Samples of blood were drawn at 1, 7, 14, and 28 days after soman or sham exposure. In the sham-exposed groups, significant changes from the reference values were observed as a result of the 24-hour restraint. In both breeds, skeletal muscle enzyme activities were increased, plasma Cholinesterase activity (ChEPL) was decreased, calcium concentration was decreased, and phosphorus concentration was increased. Percutaneous exposure to soman resulted in decreases of ChEPL and erythrocyte Cholinesterase activities (ChERBC). The ChEPL recovered more quickly than the ChERBC in both breeds. Even in asymptomatic swine, the decrease of ChEHBC was > 60% after 24 hours. In the swine of each breed given the largest dosage, hyperglycemia was apparent in blood samples taken at the onset of apnea, especially when the animal survived for > 2 hours. We conclude that both breeds of swine, on the basis of dispersion in clinical chemistry reference values, were equally suited for this type of dermatotoxicity study. The sling method of restraint, however, caused some undesirable changes in biochemical values.
Immunohistochemical diagnosis of toxoplasmosis in fetuses and fetal membranes of sheep
Authors: Uggla A. , Sjöland L. , Dubey J. P.
Published: February 2025

A peroxidase antiperoxidase technique was developed for visualizing intact Toxoplasma gondii and its antigenic residues in sections of formalin-fixed, paraffin-embedded tissues from fetal membranes recovered from ewes with induced toxoplasmosis. The peroxidase antiperoxidase method was specific and sensitive, allowing the detection of T gondii antigen even in severely decomposed tissues. Toxoplasma gondii infection was most commonly demonstrated in the cotyledons, heart, lungs, brain, and skeletal muscles of the fetus.
Pneumonie pasteurellosis: Examination of typable and untypable Pasteurella haemolytica strains for leukotoxin production, plasmid content, and antimicrobial susceptibility
Authors: Chang Yung-Fu , Renshaw Harland W. , Young Ry
Published: February 2025

Plasmid DNA screening experiments were conducted to determine whether a relationship existed between the presence of plasmids and antibiotic resistance in Pasteurella haemolytica or the capability to produce hemolysin or leukotoxin (cytotoxin). Regardless of plasmid content, all P haemolytica isolates produced characteristic hemolysis on blood agar plates. Similarly, standardized suspensions of living bacteria and sterile concentrated (approx 200:1) culture supernatant from strains representing each of the 15 recognized P haemolytica serotypes and 7 field strains of P haemolytica (biotype A, serotype 1) produced leukotoxin, which was detected by their capability to cause inhibition of the luminol-dependent chemiluminescence response of bovine neutrophils. However, neither living bacterial suspensions nor concentrated culture supernatant from 4 untypable P haemolytica strains or a P multocida strain caused an inhibition of the luminol-dependent chemiluminescence response. The production of neither hemolysin nor leukotoxin by P haemolytica seemed to be plasmid mediated. Leukotoxin production is apparently a stable phenotypic characteristic of pathogenic P haemolytica strains, and the gene(s) coding for this activity is probably located on the bacterial host chromosome. Antibiotic susceptibility profiles were determined for the different bacterial strains. Studies of ampicillin and penicillin resistance in 8 P haemolytica (biotype A, serotype 1) strains provided evidence that the plasmid, with size of approximately 5,200 base pairs, may code for their resistance to these compounds.
Shiga-like toxin production and attaching effacing activity of Escherichia coli associated with calf diarrhea
Authors: Mainil Jacques G. , Duchesnes Christiane J. , Whipp Shannon C. , Marques Lilian R. M. , O'Brien Alison D. , Casey Thomas A. , Moon Harley W.
Published: February 2025

Four hundred twenty-nine isolates of Escherichia coli from calves were tested for the production of HeLa cell cytotoxin(s). Isolates that produced enough cytotoxin to be detected in culture supernatants of iron-depleted broth were considered to produce increased amounts of cytotoxins. Isolates also were tested for homology with a DNA probe for a gene that encodes localized adherence of human enteropathogenic E coli. Four isolates produced increased amounts of cytotoxin that was neutralized by Shiga antitoxin (toxin designated as Shiga-like toxin-I [slt-I]). A 5th isolate produced increased amounts of cytotoxin (slt+) that was not neutralized by the Shiga antitoxin, but was neutralized by antitoxin against a variant of slt (toxin designated as slt-II). None of the isolates hybridized with the probe for the localized adherence gene. Three of the slt+ isolates belonged to human enteropathogenic E coli serogroups O26 and O111. All 5 of the slt+ isolates were from calves with diarrhea, but none of the 5 slt+ isolates contained genes for classic heat-labile or heat-stable enterotoxins, for K99 fimbriae, or for invasiveness; neither did any of them adhere to HeLa cells in culture. Three of the 5 slt+ isolates had attaching and effacing activities when inoculated into ligated intestinal loops of rabbits. One of the isolates with attaching and effacing activity in rabbits was originally isolated from a calf with lesions characteristic of those produced by attaching effacing E coli (aeec). Calves inoculated with this slt+ aeec isolate developed focal colonic lesions characteristic of those produced by aeec, but did not develop diarrhea. Seemingly, increased slt production and aeec activity occur together in some E coli isolates from calves in the United States. However, the prevalence of such isolates in the collection studied was low.
Serum agglutinin titers against somatic and flagellar antigens of Campylobacter jejuni and isolation of Campylobacter spp in chickens
Authors: Yoshida Shin-ichiroh , Kaneko Ken-ichi , Ogawa Masuo , Takizawa Takayasu
Published: February 2025

From June 1983 to June 1984, two hundred twenty-five 3- to 30-month-old chickens (hens) on 10 different farms were examined for Campylobacter spp. Watering trays and fly vectors also were examined for Campylobacter spp on 6 of the 10 farms. Campylobacter jejuni was isolated from fecal specimens from 64 hens (28.4%), C coli was isolated from 6 hens (2.7%), and C laridis was isolated from 9 hens (4%). The isolation rate of C jejuni was 6.7% to 46.7% for 9 of the 10 farms. On 2 farms, agglutinin titers ≥ 1:40 against somatic and flagellar antigen of C jejuni were detected in hens from which the bacteria were isolated. Hens having titers ≥ 1:40 against C jejuni or hens from which C jejuni had been isolated often occupied adjacent pens. Campylobacter jejuni was isolated from a watering tray on 1 farm and from fly vectors on 2 farms.
Efficacy, safety, and residue evaluation of levamisole gel formulation in sows
Authors: Berger H. , Garces T. R. , Fisher R. K. , DeLay R. L. , Gale G. O. , Boyd J. E. , Simkins K. L.
Published: February 2025

Anthelmintic efficacy, safety, and residue studies were conducted in sows and gilts with a levamisole gel containing 11.5% levamisole HCl. In 12 sows and 12 gilts, 8 mg of levamisole HCl equivalent/kg of body weight orally was 100% (resinate) and 91.1% (gel) effective against 55-day-old Ascaris suum and 100% (gel) and 96.1% (resinate) effective against Oesophagostomum dentatum.

In 20 sows given levamisole gel (8 mg of levamisole HCl/kg) orally just before breeding, 4 to 6 weeks after breeding, 4 to 6 weeks before farrowing, and just before farrowing, there were no adverse effects. Transient salivation was noticed in five sows after treatment.

In 4 groups of 4 sows each given levamisole gel orally to provide 8, 24, 40, or 80 mg of levamisole HCl/kg, adverse clinical signs were not observed in sows treated with 8 mg/kg. Transient salivation was noticed in one sow given 24 mg/kg, two sows given 40 mg/kg, and four sows given 80 mg/kg. Multiple emesis and chomping occurred in one sow given 80 mg/kg.

Levamisole residues in edible tissues from sows given 8 mg of levamisole gel/kg orally were < 0.1 mg/kg of muscle and fat in sows killed on posttreatment day (ptd) 3 and < 0.1 mg/kg of kidney in sows killed on ptd 5. Liver residues averaged 0.78 mg/kg in sows killed on ptd 3 and were reduced to 0.31 mg/kg in sows killed on ptd 5. The 99% upper tolerance limit with 95% confidence on the withdrawal time to assure levamisole residues of < 0.10 mg/kg in liver tissue was 11 days.
Acute changes in pancreatic insulin secretion and hepatic glucose kinetics in endotoxemic miniature pigs
Authors: Fettman Martin J. , Hand Michael S. , Van Order Paula , Phillips Robert W.
Published: February 2025

We have proposed a misinformed B-cell hypothesis to describe the effects of increased glucose flux across the pancreatic B cell early in endotoxemia, whereby those cells might misinterpret the true glycemic state and thus induce increased insulin release. This hypothesis was supported by the observations that [6-3H]glucose-derived rates of glucose disappearance increased before systemic hyperinsulinemia appeared in endotoxemic Yucatan miniature pigs. Reevaluation of this hypothesis later showed that pancreatic insulin secretion increased before any changes in systemic glucose disappearance or insulin concentrations and, because of significant increases in hepatic insulin extraction, may have led to some local effects of insulin on hepatic carbohydrate metabolism. The present study was conducted with more frequent sampling periods early during endotoxemia to further characterize the effects of this initial acute increase in pancreatic insulin secretion on hepatic glucose uptake, concomitant to net hepatic glucose production, as well as to further clarify the temporal relationships between pancreatic insulin release and the onset of hypoglycemia.

We found that an increase in pancreatic insulin secretion is, indeed, the first event to occur, 30 minutes after initiation of endotoxin infusion, coincidental to the onset of significant decreases in portal and hepatic venous blood flow. [33H]Glucose-derived rate of glucose disappearance first increased significantly at 60 minutes, and net hepatic glucose output increased significantly after 80 minutes of endotoxin infusion. Net [3-3H]glucose uptake by the liver occurred through 50 minutes of endotoxin infusion. After this, there was a significant reversal in transhepatic isotope kinetics, resulting in net release of [3-3H]glucose from the liver for the duration of endotoxin infusion (140 minutes). Rerelease of [3-3H]glucose from the liver occurred coincidental to significant increases in pancreatic insulin secretion, hepatic insulin extraction, and concurrent net hepatic glucose production. This rerelease of [3-3H]glucose from the liver may contribute, in part, to underestimation of [3H]glucose-derived rates of glucose appearance during endotoxemia and account for discrepancies between actual rates of glucose infusion and derived rates of glucose appearance during euglycemic clamps of endotoxemic pigs. The extreme degree of glucoregulatory counterstimulation due to enhanced hepatic insulin extraction, probable increases in glucocounterregulatory hormone secretion, and alterations in hepatocellular energy charge and decreased nucleotide levels may have contributed to increased rates of futile cycling of glucose through hepatic metabolic pathways during acute endotoxemia.
In vitro platelet release by rat megakaryocytes: Effect of heterologous antiplatelet serum
Authors: Handagama P. J. , Jain N. C. , Feldman B. F. , Farver T. B. , Kono C. S.
Published: February 2025

A visual assay to study megakaryocte platelet release via proplatelet formation in vitro was established. Samples of megakaryocte-enriched rat bone marrow were incubated (37 C) in rpmi-1640 medium with 15% autologous serum in specially prepared chambers. In the culture system, approximately 6% of megakaryocytes formed proplatelet processes within 24 hours. Inclusion of a heterologous antiplatelet antibody in the culture system inhibited proplatelet formation, compared with that in controls.
Evaluation of granulocyte transfusion in healthy neonatal pony foals
Authors: Morris Debra Deem , Bruce James , Gaulin Ginette , Whitlock Robert H.
Published: February 2025

Granulocyte transfusions (gt), 0.98 × 109 neutrophils/Kg of body weight, were performed on 7 healthy pony foals between 2 and 7 days old. The mean neutrophil count of the foals was significantly (P < 0.05) greater than base line (4,830 ± 1,260/μl) 1 hour after gt (8,870 ± 3,350/μl) and was similar to base line by 15 to 18 hours after gt (6,550 ± 2,310/μl).

Leukocyte concentrates (lc) used for gt were harvested from clinically normal adult horses by continuous-flow centrifugation leukapheresis (cl), 3 to 6 hours after hydrocortisone sodium succinate was administered to increase the blood neutrophil count. The mean neutrophil count of the lc used for gt was 68,050 ± 13,990/μl, and the mean lc volume was 377.4 ± 79.2 ml (14.82 ± 3.54 ml/kg). The mean time required to collect the lc used for gt was 232.1 ± 73.4 minutes. Neutrophils from lc had significantly reduced in vitro stimulated migration to zymosan-activated serum, when compared with peripheral blood neutrophils of the donors (P < 0.05). Neutrophil phagocytosis and bactericidal capacity were not significantly changed in lc. Mean neutrophil migration indices were not significantly different in foals after gt.

Mild depression and transient diarrhea was noticed in 1 foal 30 minutes after the start of the gt. The donor of lc for this foal and 1 other donor experienced depression, piloerection, and muscle tremors during cl, indicating that complement had been activated. Problems were eliminated by the use of new disposable plastic materials for blood processing in each cl procedure.
Temporal effects of halothane and isoflurane in laterally recumbent ventilated male horses
Authors: Dunlop C. I. , Steffey E. P. , Miller M. F. , Woliner M. J.
Published: February 2025

Cardiopulmonary function was monitored in 6 nonmedicated, healthy male horses, anesthetized with halothane or isoflurane in O2 at a constant dose (1.2 times the minimum alveolar concentration). Horses were exposed once to each anesthetic agent, and a minimum of 2 weeks separated anesthetic exposures. All horses were studied in left lateral recumbency, and ventilation was mechanically controlled to induce a PaCO2 of 35 to 45 mm of Hg and an inspiratory peak airway pressure of 18 to 22 cm of H2O. After 1 hour of horse preparation, constant conditions were begun. With duration of anesthesia, cardiac output increased (P < 0.05) with both anesthetic agents, because of an increase in stroke volume (P < 0.05). Heart rate did not change from initial values with either agent. Mean arterial blood pressure also increased (P < 0.05) with both agents. With both anesthetics, respiratory rate (P < 0.05) was increased progressively to maintain acceptable PaCO2 values. Arterial O2 tension did not change with time.
Response of calves to exposure with swine influenza virus
Authors: Lopez Jorge W. , Woods George T.
Published: February 2025

In calves inoculated with live swine influenza virus (siv) A/sw/IL/75 (H1N1) intranasally, siv was isolated for 7 days, and respiratory tract disease was observed. Antibody was detected in serum of inoculated calves from postinoculation day 9, and virus-neutralization antibody was demonstrated on postinoculation days 14 and 21. The primary response was low, but readily differentiated from the secondary response after calves were challenge exposed with homologous siv. Pneumonic lesions were observed at necropsy, and histopathologic changes in airways and lungs were consistently found. Fluorescent staining revealed viral activity in epithelial cells of airways. The virus was transferred to healthy calves housed with inoculated calves.
Comparison of methods used to collect canine intestinal tissues for histologic examination
Authors: Fenwick Brad W. , Kruckenberg S.
Published: February 2025

Five commonly used methods of collecting canine intestinal tissues for histologic examination were compared by analysis of the histologic artifact frequency, types, and severity, using a double-blind study design. Tissue samples from the duodenum, jejunum, ileum, and colon from 12 dogs were collected, using the following methods: method 1, longitudinally incising the intestine along the antimesenteric border and stapling the free ends of the intestine to a wooden tongue depressor; method 2, ligating the ends of an unopened length of intestine and injecting the lumen with formalin; method 3, longitudinally incising the intestine along the antimesenteric border and laying the opened intestine on a dry paper towel with the serosal surface down; method 4, placing a segment of unopened and uninjected intestine directly into formalin; and method 5, longitudinally incising the intestine along the antimesenteric border. All tissues were fixed by immersion in neutral-buffered 10% formalin and were processed, using routine histologic techniques. Two of these dogs were perfused iv with formalin before tissues were collected. Samples of intestinal tissue were examined by scanning electron microscopy to confirm the histologic findings.

Method 2 resulted in significantly fewer and less severe artifacts (P < 0.02) than did the other methods. Method 4 resulted in significantly more artifacts of greater severity (P < 0.02) than did the other methods. The number of artifacts and the severity of artifacts induced by methods 1, 3, and 5 were not significantly different. Significantly (P < 0.05) more artifacts and artifacts of greater severity occurred in the duodenum and jejunum than occurred in the ileum and colon, regardless of the method used.
Effect of intramammary devices on the outcome of induced Escherichia coli infection of bovine mammary quarters
Authors: Bright Susan A. , Schultze W. Donald , Paape Max J. , Peters Robert R.
Published: February 2025

Eighteen Holstein cows, free of intramammary infection, were fitted with smooth (n = 9) or abraded (n = 9) intramammary devices (imd) in 2 diagonally opposed quarters within 4 weeks after calving. The 2 other quarters of each cow were used as controls. Three to 6 weeks after imd insertion, depending on when milk somatic cell counts returned to a base-line value of < 4 × 105/ml, all cows were subjected to bacterial challenge exposure in the front or rear quarters by intracisternal injection of about 30 colony-forming units of Escherichia coli/quarter. Challenge exposure was done immediately after milking. Three weeks after the initial bacterial exposure, the other quarter pairs were similarly challenge exposed. Quarter bacteriologie status, concentration of milk somatic cells, and clinical observations (rectal temperature, milk appearance, udder palpation, and general condition of the cow) were monitored.

Infection developed in 14 of 16 (88%) quarters with smooth imd vs 16 of 16 (100%) control quarters and in 7 of 17 (41%) quarters with abraded imd vs 17 of 17 (100%) control quarters. The difference in infection frequency between quarters with smooth imd and quarters with abraded imd was significant (P < 0.05). Protection against establishment of infection was associated with somatic cell counts > 8.0 × 105/ml in milk collected immediately after milking (7 of 12 quarters) or 4 hours later (11 of 12 quarters). In 10 quarters (59%) of cows fitted with abraded imd, secretory abnormalities appeared before bacterial challenge inoculation. Abnormal milk or visible blood was observed over periods varying from 2 weeks after insertion through the entire lactation.