bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Experimental Subunit Vaccines for Infectious Bovine Rhinotracheitis
Authors: Lupton H. W. , Reed D. E.
Published: February 2025

Subunit infectious bovine rhinotracheitis (ibr) antigens were prepared by solubilization of ibr-virus infected cell cultures with nonionic detergents Triton X-100 and NP-40. When used with Freund's incomplete adjuvant, Triton X- 100 and NP-40 subunit antigens induced high serum-neutralization titers in vaccinated calves. Two doses of Triton X-100 and NP-40 subunit vaccines prevented the appearance of clinical signs of disease in all vaccinated calves exposed 30 days after the second vaccinal dose to intranasal challenge exposure with Cooper strain of ibr virus. Furthermore, two doses of NP-40 subunit vaccine prevented shedding of the virus in all vaccinated calves after challenge exposure.
Effect of Butylated Hydroxytoluene on Newcastle Disease Virus
Authors: Winston Vern D. , Bolen Joseph B. , Consigli Richard A.
Published: February 2025

A study was done to examine the effects of butylated hydroxytoluene (bht) on purified Newcastle disease virus (ndv). Treatment of the virus with 50 µg of bht/ml caused 92% inactivation of the virion infectivity. Virion adsorption to chicken-embryonated cells was inhibited 32% and synthesis of intracellular hemagglutinin was inhibited 29%. Electron microscopy of the bht-treated virions revealed virion envelope damage.

Chicken-embryonated cells treated with 25 µg of bht/ml before ndv infection demonstrated 65% inhibition of ndv progeny production.
Leishmaniasis: In Search of New Chemotherapeutic Agents
Authors: Kinnamon Kenneth E. , Steck Edgar A. , Loizeaux Peter S. , Chapman Willie L. , Waits Virginia B. , Hanson William L.
Published: February 2025

Members of a class of compounds designated lepidines (8-amino-6- methoxy-4-methylquinoline derivatives) were tested in a hamster-Leishmania donovani model and found to have activity many-fold that of a reference drug meglumine antimoniate. One of them, 8-(7-isopropylaminoheptylamino)-6-methoxy-4-methylquinoline, was found to be 138 times as effective as the standard antimonial drug used.
Efficacy of Albendazole and Levamisole in Sheep Against Thysanosoma actinioides and Haemonchus contortus from the Edwards Plateau, Texas
Authors: Craig T. M. , Shepherd Eric
Published: February 2025

Lambs naturally infected with Thysanosoma actinioides and naturally and experimentally infected with Haemonchus contortus were used in a controlled experiment to determine the anthelmintic activity of albendazole as compared with levamisole. The lambs were given 10,000 H contortus larvae 25 to 35 days before treatment, were slaughtered 7 to 9 days after treatment, and were housed on concrete from the time of treatment until slaughter.

In lambs given doses of 7.5 mg or 3.8 mg of albendazole/kg or 7.5 mg of levamisole/kg, reductions in numbers of H contortus were 99%, 85%, and 98%, respectively. Reductions in numbers of T actinioides were 98%, 45%, and 0% respectively, as compared with untreated controls.
Sequential Ultrastructural Alterations in Ventricular Myocardium of Dogs Given Large Single Transthoracic Damped Sinusoidal Waveform Defibrillator Shocks
Authors: Van Vleet John F. , Tacker W. A. , Geddes L. A. , Ferrans Victor J.
Published: February 2025

Fifty-six dogs were allotted to eight groups and were given no shock or a single transthoracic damped sinusoidal waveform shock of 1, 3, 6, 9, 12, 15, and 20 A/kg of body weight. The dogs were euthanatized at 1 day, 2 days, 4 days, 2 weeks, and 8 weeks after shocking and small blocks of ventricular myocardium were collected for ultrastructural study from dogs given large (15 and 20 A/kg) shocks from the center of the defibrillator-induced areas of myocardial necrosis. Early (days 1, 2, and 4 after shock) ultrastructural alterations in myocardium were characterized by myocyte necrosis with contraction bands (myofibrillar degeneration). Mitochondria in damaged myocytes had flocculent matrical densities at 1 day after shock; by 2 days or more after shock mitochondria were mineralized with dense granular and spicular matrical deposits. Mineralization was also present in the lysed masses of contractile material in necrotic myocytes by 2 days or more after shock. Interstitial edema was prominent for the first 4 days after shock. Numerous neutrophilic granulocytes were in the interstitium and had invaded necrotic myocytes at 1 and 2 days after shock. By 4 days, many macrophages were infiltrated in the interstitium and into necrotic fibers and had engulfed masses of necrotic, and often mineralized sarcoplasmic debris. External laminae persisted in myocytes undergoing necrosis.

Resolving lesions were present in areas of damaged myocardium at 2 weeks and 8 weeks after shock. Only remnants of external laminae remained where myopes had undergone necrosis. The interstitium contained activeappearing fibroblasts, abundant accumulations of collagen fibrils, and occasional macrophages. In these areas of myocardial scarring, some myocytes had persisted but were degenerated as indicated by atrophy, lysis of myofibrils (myocytolysis), and focal proliferation of elements of sarcoplasmic reticulum.
Observations on Calcium Metabolism, 47Ca Absorption, and Duodenal Calcium-Binding Activity in Chronic Renal Failure; Studies in Beagles with Radiation-Induced Nephropathy
Authors: Norrdin R. W. , Miller C. W. , LoPresti C. A. , Taylor A. N. , Arnold J. S.
Published: February 2025

Observations on clinical and biochemical changes in calcium metabolism in Beagles with experimental chronic renal failure are reported. In this model of renal osteodystrophy, there are chronic progressive glomerulosclerosis and loss of outer cortical nephrons as a result of perinatal irradiation. The parathyroid glands become hyperplastic and the bone changes are principally those of secondary hyperparathyroidism with increased remodeling activity. In blood samples from 16 dogs with progressive renal failure, there was a positive correlation of phosphorus with serum urea nitrogen. There was no correlation of serum calcium with serum urea nitrogen or of serum calcium with serum phosphorus Dogs killed with marked uremia (serum urea nitrogen > 75 mg/100 ml) had significantly increased urinary calcium, phosphorus, and hydroxyproline levels (mg/kg/24 hrs). The calcium and phosphorus excretion was correlated with declining glomerular filtration rate, as measured by Na sulfanilate clearance. In a 7-day calcium balance trial, one of four uremic dogs was in negative balance with increased fecal loss of calcium. 47Ca absorption was measured in 6 dogs and no defect could be demonstrated in three of the dogs which were uremic. Examination of duodenal calcium-binding activity revealed significantly decreased activity in all irradiated dogs irrespective of renal functional status. This finding would seem to be specific for the model and might be related to loss of renal cortical tubules involved in vitamin D metabolism. The increased urinary excretion of calcium also differs from the usual findings in persons. The lack of a consistent absorption defect in these dogs may be attributable to non-vitamin D dependent calcium absorption at high levels of intake.
Factors Affecting the Assay of Bovine Type I Interferon on Bovine Embryonic Lung Cells
Authors: Rossi Charles R. , Kiesel George K. , Hoff Edwin J.
Published: February 2025

One preparation of interferon (if) on 7-day-old bovine embryonic lung cultures free of bovine viral diarrhea virus had titers ranging from 20 to 10,240 in plaque-reduction tests, using bovine vesicular stomatitis virus. Factors believed to contribute to this variation were investigated.

Although titers differed on different cell strains, different passages, and on cultures of different ages, variations between the two assays definitely could not be established as a function of these factors. However, if titers on low passage cultures were usually lower than were titers on subsequent passages of the same cell strain. Calf serum in the diluent for if reduced the titer one or two twofold dilutions. Over the range of 7 to 24 hours contact of if with bovine embryonic lung cultures, the titer decreased steadily and was one twofold dilution less at 24 hours than it was at 7 hours.

Latent viruses were not found in cultures by electron microscopy. Treatment of cultures with a noncytopathogenic strain of bovine viral diarrhea virus almost eliminated the effect of if. Naturally occurring production of if was not a major problem. While if was on the cells, the pH of if had a pronounced effect on the titer and may have been responsible for the variation observed with different passages, different cell strains, use of cultures of different ages, and use of calf serum in the diluent. Interferon at a low pH had a titer three or four twofold dilutions less than did the if at a high pH.
Evaluation of a Hemolysis-in-Gel Test for Detection and Quantitation of Antibodies to Bluetongue Virus
Authors: Jochim M. M. , Jones S. C.
Published: February 2025

A hemolysis-in-gel (hig) test was developed to detect and quantitate antibody to bluetongue virus (btv). The hig test was sensitive and accurate when applied to sera from sheep and cattle infected with btv. Sensitized sheep rbc were prepared by adsorption of partly purified btv to the cells. Regression analysis of data showed a linear relationship between the diameter of the hemolytic zone and the log of the antibody concentration. The hig test did not differentiate among antibodies to four serotypes of btv, but did differentiate between antibody to btv and antibody to epizootic hemorrhagic disease virus.
Longitudinal Study of Phenobarbital in Serum, Cerebrospinal Fluid, and Saliva in the Dog
Authors: Skinner Steven F. , Robertson Lee T. , Artero Mary , Gerding Robert K.
Published: February 2025

Serial assays for phenobarbital were done on the blood serum, cerebrospinal fluid (csf), and saliva from three epileptic and two clinically normal dogs that were given various oral doses of the drug. In all dogs, the three fluids showed considerable daily fluctuations of phenobarbital concentrations, even after several weeks at the same dosage. The average ratio for csf/serum was 0.53 and 0.39 for saliva/serum. A highly significant (P < 0.001) correlation coefficient occurred between csf and serum (0.95) and between csf and saliva (0.93); although in some dogs at particular dosages, the csf and saliva were poorly correlated. Dose-related curves demonstrated a gradually increased phenobarbital concentration in the three fluids up to dosages of 9.0 mg/kg of body weight. The present study suggests that multiple serum or saliva samples should be assayed to account for daily fluctuations; saliva can be a good indicator of unbound phenobarbital concentration in csf.
Enzyme-Linked Immunosorbent Assay for Evaluation of Antibody to Canine Distemper Virus
Authors: Noon Kerry F. , Rogul M. , Binn L. N. , Keefe T. J. , Marchwicki Ruth H. , Appel M. J.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) for canine immunoglobulin (Ig) G antibodies to canine distemper virus (cdv) was developed and its test results were compared with those of the serum-neutralization (sn) test. The sera of 273 random-source adult dogs were examined. The two tests had a high degree of correlation. Very few discrepancies occurred and most of these were at the lower limits of each test. When the sera were tested at 1:100 dilution, there was a 98% agreement between the elisa and sn test. Titrated sn and IgG elisa tests also were performed on sera from 77 dogs whose lifetime medical histories were known. The results showed excellent agreement between the tests. Only five of the 77 sera showed any discrepancies and these were at detection-threshold levels.

To follow antibody development in two dogs experimentally infected with cdv, it was necessary to use an elisa which detected both canine IgM and IgG. The elisa detected CDV-specific IgM a week before the sn test results became positive. The IgM titers rose for 3 weeks and descended to lower levels about the 4th and the 5th weeks. The sn titers closely followed the IgM titers. The elisa detected IgG antibody about the 5th and the 6th weeks of infection. Results of both the sn test and the IgG elisa remained elevated through the 70th day of testing.
End-Tidal Partial Pressure of CO2 as an Estimate of Arterial Partial Pressure of CO2 During Various Ventilatory Regimens in Halothane-Anesthetized Dogs
Authors: Hightower C. E. , Kiorpes A. L. , Butler H. C. , Fedde M. R.
Published: February 2025

The correlation between end-tidal partial pressure of CO2 (Petco2) and arterial Pco2 (Paco2) was studied in six halothane-anesthetized dogs maintained under four different ventilatory regimens: (A) spontaneous breathing; (B) assisted positive-pressure ventilation; (C) intermittent manual inflation; and (D) ventilator-controlled breathing. For procedures A, B, and D together, there was a strong correlation between PetCo2 and PaCo2 (r = 0.8) that was highly significant at P < 0.0001 for Petco2 values between 31.3 and 61 mm of Hg. In spontaneous and controlled breathing, Petco2 is representative of PaCo2 and provides a useful noninvasive tool for monitoring the patient maintained under general anesthesia. Furthermore, data suggest that any ventilatory support of the anesthetized patient markedly improves blood gas and acid-base status compared with that of the unsupported, spontaneously breathing animal.
Vascular Responses in Equine Thoracic Limb During and After Pneumatic Tourniquet Application
Authors: Sandler G. A. , Scott E. A.
Published: February 2025

Vascular responses occurring with pneumatic tourniquet application were evaluated in the equine thoracic limb. Recordings of pressure (arterial and venous) and flow (arterial) distal to the tourniquet were made for 60 minutes. Reactive hyperemia was observed; however the increased flow was neither of a sufficient duration nor of a great enough volume for total repayment of flow loss.
Characterization of Immunoglobulin A Antibody in Serum of Swine Inoculated with Transmissible Gastroenteritis Virus
Authors: Kodama Y. , Ogata Μ. , Simizu Y.
Published: February 2025

Sera and contents of the small intestine from swine inoculated with transmissible gastroenteritis (tge) virus were examined for immunoglobulin (Ig) A antibody responses by the radioimmunoprecipitation test with antiporcine IgA serum. When swine were orally inoculated with virulent virus, IgA antibody activity was detected in the contents of the small intestine and in serum from postinoculation days 7 to 56. However, IgA antibody activity was not detected in the contents of the small intestine or serum in swine inoculated im with attenuated virus.

The Ig class of serum of swine inoculated with tge virus was examined by gel filtration chromatography. When swine were orally inoculated with virulent virus, neutralizing antibody was always detected from both fractions of IgA and IgG. Neutralizing antibody was detected only from the IgG fraction in the serum of swine inoculated im with attenuated virus.

The molecular size of serum IgA antibody was determined by sucrose density gradient centrifugation. The titer of this antibody was the highest at a position between 10.9S- and 7S-marker protein. The antibody consisted almost exclusively of dimers.

It appeared that serum IgA antibody always originated from the lymphoid tissue of the intestinal tract. This antibody was regarded as an indicator of active immunity to tge virus.
Biochemical Effects of Succinylcholine Chloride in Mechanically Ventilated Horses Anesthetized with Halothane in Oxygen
Authors: Benson G. J. , Hartsfield S. Μ. , Manning J. P. , Thurmon J. C.
Published: February 2025

Succinylcholine chloride administered to horses anesthetized with halothane in oxygen and mechanically ventilated, caused slight but statistically insignificant (P < 0.01) increases in creatine phosphokinase, lactic dehydrogenase, and aspartate aminotransferase activity. The increases in these enzymes have been explained on the basis of muscle damage resulting from succinylcholine chloride induced muscle fasciculations and by hypoperfusion of tissues due to depression of the cardiovascular system caused by general anesthesia. These changes were not clinically apparent based upon the absence of myoglobinuria and ease of recovery. There was no significant effect of treatment observed on other biochemical variables. The findings in the present study agree with previous observations on serum creatine phosphokinase, lactic dehydrogenase, and aspartate aminotransferase activity.
Chemically Defined Growth Medium for Corynebacterium pyogenes
Authors: Reddy C. Adinarayana , Cornell C. P. , Fraga A. Μ.
Published: February 2025

A chemically defined medium and a relatively simple semidefined medium (sdm) which allow good growth of Corynebacterium pyogenes, a nutritionally fastidious animal pathogen, were described. The sdm contained glucose, trypticase, yeast extract, hemin, minerals, cysteine · HCl, and NaHCO3. To obtain a chemically defined medium, yeast extract in sdm was replaced with a defined mixture of nucleic acid bases, vitamins, amino acids, and trace minerals, and trypticase was replaced by myo-inositol (1 μg/ml of medium).
Effect of Prednisone on Gastric Blood Flow in Swine
Authors: Zamora C. S. , Reddy V. K. , Frandle K. A. , Samson M. D.
Published: February 2025

The effect of long-term prednisone treatment on gastric blood flow, as it relates to the development of gastric lesions, was studied. Young pigs were given (im) saline solution or prednisone (10 mg/kg) each day for various periods. Blood flow was measured, using the radioactive microsphere entrapment technique, at the end of 7, 14, and 21 days of treatment. Pigs treated with prednisone had hemorrhages in the proper gastric (fundic) gland area of the stomach. Blood flow to the mucosa and total wall of the nonglandular, cardiac gland, fundic gland, and pyloric gland regions of the stomach was higher in prednisone-treated pigs. Gastric lesions were not observed in the saline-treated pigs. Regional blood flow to the gastric mucosa increased during the formation of prednisone-induced gastric lesions in swine.
Effect of Multiple Excretory Urograms on Glomerular Filtration of Normal Dogs: A Preliminary Report
Authors: Feeney D. A. , Osborne C. A. , Jessen C. R.
Published: February 2025

Study was made of the effect of a triiodinated radiopaque contrast agent, sodium iothalamate on glomerular filtration of ten normal dogs given the dosages commonly recommended for diagnostic studies—200, 400, and 800 mg of iodine/0.45 kg of body weight administered at 2- to 6-day intervals. Renal function was evaluated by determination of serum urea nitrogen and serum creatinine concentrations and endogenous creatinine clearance immediately before each urogram and at 2 to 5 days after the last urogram. Although no significant changes in serum urea nitrogen or creatinine concentrations were identified, a statistically significant reduction in endogenous creatinine clearance following urography was identified when the data from all the dogs were evaluated as a group. However, only 3 of the 10 dogs had successively decreasing values on serial evaluations of endogenous creatinine clearances and an additional 2 animals had final endogenous creatinine clearances further than 1 sd below the preinjection (base line) mean for that animal.

Serial renal function studies will be required in dogs given a single dose of the radiopaque contrast to determine the reversibility of the decreased endogenous creatinine clearance and the significance of the decreased creatinine clearances when compared with those values in control dogs (not given radiopaque contrast medium). In addition, these studies may reveal whether the incidence, degree, and duration of reduced glomerular filtration are related to the dose rate of radiopaque contrast agent and are statistically significant were greater numbers of dogs given single and multiple doses of radiopaque contrast agent under laboratory conditions.
Activation of Antibacterial Silver Coatings on Surgical Implants by Direct Current: Preliminary Studies in Rabbits
Authors: Colmano G. , Edwards S. S. , Barranco S. D.
Published: February 2025

Staphylococcus aureus contamination on intramedullary silver pins in the femurs of rabbits was decreased 69% by the application of 9 μA for 1 hour of positive direct current/cm2 (9μAH+DC/cm2). Injection of a solution of silver chloride or silver nitrate into the bone marrow before insertion of the contaminated pins and subsequent application of 12 μAH+DC/cm2 to the stainless steel pins reduced the colony counts 25% and 64%, respectively, and indicated a need for the Ag+ and Cl− ionic state on the pins’ surfaces. Stainless steel pins electroplated with silver and charged with 12 μAH+DC/cm2 decreased the bacterial counts by 85%. A 91% inhibition with stainless steel pins electroplated with silver and chlorided indicated that bacteriostasis was possibly due to the Ag+/AgCl/Cl− surface effect. Total bacterial inhibition was achieved by 12 μAH+DC/cm2 on stainless steel pins coated with 100 monomolecular layers of silver stearate. The electrical activation of this coating eliminated up to ~3,000 S aureus contaminating the intramedullary pins.
Occurrence and Properties of Haemophilus avium Hemagglutinin
Authors: Iritani Y. , Yamaguchi T.
Published: February 2025

Hemagglutination studies on Haemophilus avium were done, using chicken rbc. Direct hemagglutinin was found in H avium cultured in solid medium. Hemagglutination ability was inactivated by heating and with formalin, but was not affected by sonication and by freezing and thawing. Serologic differences between H avium and H paragallinarum were verified by the hemagglutination-inhibition test.
Electrocardiograms of Nine Species of Nonhuman Primates Sedated with Ketamine
Authors: Gonder Janet C. , Gard Elizabeth A. , Lott Nathaniel E.
Published: February 2025

Electrocardiograms were studied in nine species of nonhuman primates sedated with ketamine hydrochloride. Electrocardiographic values were similar in all species although heart rate and other rate-related values (QT and PR intervals) were species-dependent. Arrhythmias were infrequent. Ketamine hydrochloride did not appear to induce marked alterations in the ecg of primates.
Abnormalities and Virus-Like Particles in Spermatozoa from Bulls Latently Infected with Bluetongue Virus
Authors: Foster N. M. , Alders M. A. , Luedke A. J. , Walton T. E.
Published: February 2025

Abnormalities were commonly observed in spermatozoa, and bluetongue virus (btv) was isolated from semen of 2 known btv carrier bulls and 2 of 4 btv seropositive field bulls. The spermatozoal abnormalities ranged from a small cavity between the acrosome and nucleus with some involvement of the nucleus, to an enlargement of the cavity accompanied by vesiculation that could affect the entire acrosome. Virus-like particles were occasionally observed in the affected spermatozoa, but were present in all samples. A positive relationship was found between infectivity of semen samples from btv latently infected bulls and the observation of abnormalities and virus-like particles in the heads of affected spermatozoa.
Pathologic Features of Iodide Toxicosis in Calves
Authors: Mangkoewidjojo Soesanto , Sleight Stuart D. , Convey Edward M.
Published: February 2025

Forty Holstein-Friesian heifer calves were divided into four groups of ten each and dosed orally with ethylenediamine dihydriodide to provide 0, 50, 250, or 1,250 mg of iodide/animal each day. Five calves in each group were given thyrotropin-releasing hormone at 4-week intervals. Two calves given 1,250 mg of iodide (active ingredient)/day died by 70 days and had severe bronchopneumonia. At 6 months, the remaining 38 calves were killed. Pneumonia was evident in calves given iodide, with the severity apparently dose-related. Squamous metaplasia of tracheal epithelium occurred in all calves given 1,250 mg of iodide. Similar changes were seen in the interlobular duct of the parotid gland of two calves given 1,250 mg of iodide and in one calf given 250 mg, Scanning electron microscopy revealed changes in the tracheal mucosa, the severity of which were related to the dose of iodide fed. Changes in the thyroid glands of calves given 1,250 mg of iodide included large follicles, flat epithelium, and large amounts of colloid. In calves given 1,250 mg of iodide plus thyrotropin-releasing hormone, the histologic features of the thyroid glands were similar to controls. Serum vitamin A concentrations were less in calves given 1,250 mg of iodide relative to that of control calves. In general, calves were able to compensate for excessive dietary iodide after an initial period of an apparent increased susceptibility to respiratory tract infection.
Comparison of Three Methods of Immunization Against Bovine Anaplasmosis: An Examination of Postvaccinal Effects
Authors: Corrier D. E. , Vizcaino O. , Carson C. A. , Ristic M. , Kuttler Κ. L. , Treviño G. S. , Lee A. J.
Published: February 2025

Normandy calves ranging in age from 7 to 11 months were immunized against bovine anaplasmosis, using a diluted virulent Anaplasma marginale stabilate of Colombian origin, diluted bovine blood containing an apparently mild strain of A marginale isolated in Colombia, or an attenuated A marginale vaccine of ovine origin from the United States. Calves given the stabilate generally showed a moderate degree of parasitemia and reduction in packed cell volume (pcv). Calves given the apparently mild Colombian isolate of A marginale developed a moderate parasitemia, a reduction in pcv, and in some instances, required treatment to moderate the premunization procedure. Calves given the attenuated vaccine showed minimal evidence of parasitemia and pcv reduction. Most of the immunized calves became seropositive in the complement-fixation test for anaplasmosis and all calves sampled showed evidence of a cell-mediated response, using the leukocyte migration-inhibition test.
Histochemical Observations on Muscle from Normal and Malignant Hyperthermia-Susceptible Swine
Authors: Gallant Esther M.
Published: February 2025

A comparison was made of muscle from two locations in both the longissimus and the semitendinous muscles of normal and malignant hyperthermia-susceptible swine. Serial frozen sections were stained for alkali-stable adenosine triphosphatase (ATPase), phosphorylase, and the oxidative enzymes succinate dehydrogenase and reduced nicotinamide adenine dinucleotide (NADH)-diaphorase. Myofiber types were identified on the basis of these staining reactions. There was no consistent statistically significant difference between muscle from normal and muscle from susceptible swine with any system of fiber classification. This is contrary to several published reports but consistent with physiologic studies which indicate that both oxidative and glycolytic pathways are abnormally active during the onset of malignant hyperthermia.
Pulmonary Vascular Response During Phases of Canine Heartworm Disease: Scanning Electron Microscopic Study
Authors: Schaub Robert G. , Rawlings Clarence A.
Published: February 2025

Pulmonary arteries and veins of 14 dogs in phases of heartworm disease (Dirofilaria immitis infection) were examined by scanning electron microscopy. Two dogs were infected with D immitis microfilaria only, whereas 12 dogs were infected with adult D immitis. Seven of the dogs infected with adult worms were untreated. Two of these 7 dogs had natural infections of unknown duration introduced by mosquito bite, whereas 5 were experimentally infected for 30 days. The remaining five dogs were experimentally infected for 1 year and had worms removed by drug therapy. These five dogs were maintained 12 months after treatment.

Arteries and veins from dogs infected with microfilaria had a continuous sheet of endothelial cells. Arterial endothelium from the seven nontreated dogs infected with adult heartworms exhibited swirling patterns, pore formation, and separation of intercellular junctions. Arteries from all dogs had numerous endothelialized villus protrusions; veins had similar, less extensive changes. Arteries and veins from experimentally infected dogs were similar to naturally infected dogs, indicating the infection procedure produced lesions similar to that normally seen in heartworm disease. The extent of vascular lesions was reduced in four of the five treated dogs that had been infected with adult worms. Adult worms, not microfilaria, may produce the vascular lesions seen in heartworm disease. Lesions will regress if worms are removed from the circulation. Lesions may be caused by generation of humoral factors initiated by the presence of adult worms.
Acrosome Reaction of Sperm Incubated in the Uterus of Gilts
Authors: Esbenshade K. L. , Clegg E. D.
Published: February 2025

A procedure is described for incubation and recovery of sperm from the female reproductive tract. Ova which were placed in Teflon capsules and surgically inserted into ligated uterine segments of gilts, were incubated with sperm and examined to determine whether the acrosome reaction was induced. Ova were recovered at 30-minute intervals for 2 hours and examined by electron microscopy. When 6 to 12 × 109 sperm were placed into the ligated uterine segments, 80% to 85% of the sperm were recovered. The acrosome reaction, with the characteristic vesiculation of the plasma membrane and outer acrosomal membrane, was detected in sperm at the surface of the ova after incubation for 60 or 90 minutes. Approximately 5% of the sperm outside the capsules showed similar membrane vesiculation after those time intervals.
Continuous In Vitro Cultivation of Babesia bovis
Authors: Erp Elton E. , Smith Ronald D. , Ristic Miodrag , Osorno B. Miguel
Published: February 2025

Babesia bovis was isolated from an experimentally infected calf (No. 1) and was maintained in vitro for 32 days by subculturing 14 times, using a total dilution of 192,000. A splenectomized calf was inoculated with subculture Babesia (isolate B). The agent (isolate C) was isolated and maintained in vitro for 17 days prior to inoculation of a third splenectomized calf. Babesia organisms (isolate D) were isolated and retained in vitro for 270 days. After 85 days in vitro, organisms from this third isolation (isolate D) were injected into a fourth splenectomized calf to test for infectivity. Responses of the three calves to cultural inoculation were similar to those responses that occurred from inoculation of infected bovine blood (calf 1). There was no observed change in the microscopic appearance of the Babesia in vitro with time.
Vaccination of Pregnant Ponies Against Equine Rhinopneumonitis
Authors: Crandell Robert A. , Mock Richard E. , Lock Theodore F.
Published: February 2025

Bovine herpesvirus 1247 (one dose) was given subcutaneously to five pregnant pony mares between 227 and 319 days of their gestations. There were no adverse clinical reactions, and the virus was not recovered from nasal swabs collected during a 2-week period after vaccination. Four ponies foaled full-term, live, healthy foals. The foal of the fifth mare (No. 1) was found dead, but on the basis of the pathologic and virologic examinations, the virus was not considered to be the cause of the death. At 3 weeks after vaccination, the pregnant pony mares had a 13- to 250-fold increase in serum antibody titer to equine herpesvirus-1.

A virulent-virus challenge exposure of all pony mares at 208 days after vaccination resulted in antibody titers greater than those just before this exposure. Virus was recovered from nasal swabs from vaccinated mares only on postexposure day 1, whereas the one control (nonvaccinated) pony shed virus for at least 3 days after challenge exposure.

The immunogenic and the nonabortifacient characteristics of the herpesvirus 1247 in pregnant pony mares indicate that it may be useful to vaccinate horses against equine herpesvirus-1.
Relationship Among Leukocyte Phagocytosis, Milk Immunoglobulins, and Susceptibility to Intramammary Infection
Authors: Guidry A. J. , Pearson R. E. , Paape M. J. , Williams W. F.
Published: February 2025

A study was conducted to determine the variation among cows (n = 7) and among quarters within cows in the ability of milk to support phagocytosis, immunoglobulin (Ig) concentration, and the response to intramammary challenge exposure with live Staphylococcus aureus. Before challenge exposure, the average concentration (milligrams/milliliter) of each class of Ig was: IgA = 0.05, IgG1 = 0.42, IgG2 = 0.06, and IgM = 0.05. The percentage of phagocytosis of S aureus by milk neutrophils was significantly correlated with IgA (r = 0.59; Ρ < 0.01), IgG1 (r = 0.52; Ρ < 0.01), and agglutination titer (r = 0.68; Ρ < 0.01). Agglutination titer was significantly correlated with IgA (r = 0.52; Ρ < 0.01) and IgG1 (r = 0.63; Ρ < 0.01). Bovine serum albumin was significantly correlated with IgA (r = 0.55; Ρ < 0.01) and IgG2 (r = 0.49; Ρ < 0.01). An IgG1/IgG2 ratio of 7.0 in milk, as compared with an IgG1/IgG2 ratio of 0.7 in serum, indicated a selective transport for IgG1.

After challenge exposure, the IgG1/IgG2 ratio in infected and noninfected quarters was 12.9 and 16.0, respectively. The fact that neither the bovine serum albumin nor the direct microscopic somatic cell count in the noninfected quarters changed indicated that the increase in the IgG1/IgG2 ratio was due to an increase in selective transport in all quarters and not to a change in permeability due to a generalized inflammatory response. The correlation between the number of challenge exposures required to produce an infection was significantly correlated with percentage of phagocytosis (r = 0.70; Ρ < 0.01).
Thermographic Diagnosis of Horner's Syndrome in the Horse
Authors: Purohit Ram C. , McCoy Michael D. , Bergfeld William A.
Published: February 2025

Lateral and frontal thermographic patterns of the head of normal horses before and after exercise were characterized to aid the diagnosis of diseases of the head. Surgical induction of Horner's syndrome was done in four horses by isolation and transection of the vagosympathetic trunk. One clinical case and the surgically induced cases of Horner's syndrome were evaluated clinically. Thermographic findings of the clinical case were similar to the experimental cases.
Maturation of Equine Epididymal Spermatozoa
Authors: Johnson Larry , Amann R. P. , Pickett B. W.
Published: February 2025

Spermatozoa from four regions of the epididymis and from ejaculated semen were evaluated for their resistance to cold shock, progressive motility, and structural stability. Spermatozoa were incubated at 38 C and their percentage of eosinophilia was compared with that of spermatozoa cooled to 0 C in 2 minutes, 10 C in 12 minutes, or 4 C in 22 minutes. Spermatozoal motility was estimated visually under phase-contrast microscopy and was recorded by cinematography. Structural stability of spermatozoa incubated in 0.05 M sodium borate buffer, 0.035 M sodium dodecyl sulfate (sds), 0.002 M dithiothreitol (dtt), or sds+dtt was evaluated by phase-contrast and electron microscopy.

The percentage of eosinophilic spermatozoa did not differ among regions of the epididymis and was not increased by cold shock. Cooling ejaculated spermatozoa to 0 C in 2 minutes increased (P < 0.01) the occurrence of eosinophilia (32% vs 73%). Spermatozoa released from the caput or proximal corpus epididymidis into 0.154 M NaCl were not progressively motile; only 4% of the spermatozoa from the distal corpus were motile. Cauda epididymal and ejaculated spermatozoa exhibited similar motility (41% vs 47%).

Stability of chromatin was greater in spermatozoa from the distal corpus than those from the caput epididymidis. Chromatin of spermatozoa from the distal corpus was resistant to 7.5 minutes of sds+dtt treatment, whereas virtually all spermatozoal nuclei from the caput were decondensed by sds alone. Tail organelles of spermatozoa acquired stability between the proximal corpus and the cauda epididymidis. All tail organelles of spermatozoa from the proximal corpus were dissolved by 7.5 minutes of sds treatment, whereas tail organelles of distal corpus epididymal spermatozoa had dissolved after 7.5 minutes of sds+dtt treatment. Stability of tail organelles in cauda epididymal and ejaculated spermatozoa was similar. Seemingly, equine spermatozoa are infertile until they enter the cauda epididymidis.
Pharmacokinetics, Bioavailability, and Dosage Regimens of Digoxin in Dogs
Authors: Button C. , Gross D. R. , Johnston J. T. , Yakatan G. J.
Published: February 2025

Digoxin, 30 μg/kg, was given by iv injection and orally, in the forms of pediatric elixir and tablet, on three separate occasions to six healthy dogs. Multiple serum samples were collected at timed intervals and assayed by radioimmunoassay. Data were analyzed, using nonlinear least squares regression analysis.

The mean serum digoxin-time relationship was triexponential. Rapid and slow distributive phases with half lives of 9 minutes and 4.7 hours were followed by a biological disposition phase with a half life of 30.1 hours. Mean volume of distribution by extrapolation was 15.6 L/kg. When calculated by the area method, mean volume of distribution was 12.4 L/kg.

Digoxin elixir was rapidly absorbed, with a mean bioavailability estimate of 71.4 ± 8.2% sd. Digoxin tablets were less rapidly and less completely absorbed, with a mean bioavailability estimate of 58.0 ± 11.6%.

Data collected in this series of experiments and data from the literature were applied to standard pharmacokinetic equations to formulate loading and maintenance doses of digoxin for the iv injection, the elixir, and the tablet. Mean loading doses were, in μg/kg/24 hours: 27, 38, and 45 for the iv injection, elixir, and tablet, respectively. Corresponding mean maintenance doses were 13, 18, and 23.
Thymic Abnormalities and Growth Hormone Deficiency in Dogs
Authors: Roth J. A. , Lomax L. G. , Altszuler N. , Hampshire J. , Kaeberle M. L. , Shelton M. , Draper D. D. , Ledet A. E.
Published: February 2025

A high frequency of occurrence of a wasting disease, unthriftiness, and retarded growth was observed in a group of inbred Weimaraner dogs. Affected pups had a small thymus gland, with a marked absence of thymic cortex. A litter of eight pups from a sire and dam that were known to have produced affected offspring was chosen for further study. The pups had normal concentrations of wbc and γ-globulins and were able to produce antibody in response to Brucella abortus. Two pups in the litter developed a wasting syndrome and responded well to therapy with thymosin fraction 5. One pup that survived the wasting syndrome had a significant (P < 0.05) depression of its lymphocyte blastogenic response to phytohemagglutinin compared with its surviving littermates. Pups from this litter also lacked a normal increase in plasma growth hormone concentration after the injection of clonidine HCl. These pups had concurrent abnormalities of the thymus-dependent immune function and in growth hormone metabolism. The syndrome in these pups has some features in common with the syndrome in the Ames or Snell-Bagg strains of immunodeficient dwarf mice.
Acute Aflatoxicosis in Guinea Pigs: Sequential Changes in Serum Proteins, Complement, C4, and Liver Enzymes and Histopathologic Changes
Authors: Thurston J. R. , Baetz A. L. , Cheville N. F. , Richard J. L.
Published: February 2025

Guinea pigs were fed a single toxic but sublethal dose of aflatoxin. Serum proteins, complement activity, fourth component of complement (C4), and liver enzymes (ornithine carbamoyltransferase and sorbitol dehydrogenase) as well as microscopic changes in liver tissue, were studied to correlate structural and functional abnormalities. There were no significant changes in serum proteins, but complement activity and C4 were depressed maximally 7 days after aflatoxin was given. The greatest activity of the liver enzymes in plasmas occurred at 3 days, although sorbitol dehydrogenase activity still was elevated significantly on the 7th day. Microscopic changes in the liver were maximum at 3 days with gradual recovery at 7, 10, and through 14 days.
Critical Evaluation of Creatine Phosphokinase in Cerebrospinal Fluid of Dogs with Neurologic Disease
Authors: Indrieri Richard J. , Holliday Terrell A. , Keen Carl L.
Published: February 2025

Creatine phosphokinase (cpk) concentrations in csf and in serum of dogs with a variety of neurologic diseases were evaluated. Concentrations of cpk in csf and serum were diagnostically nonspecific. Although a diagnostic advantage was not found in measurement of cpk concentrations in csf and serum, it appeared that increased cpk concentration in csf was associated more frequently with a guarded-to-poor prognosis.

The concentration of cpk in csf was statistically independent of cpk concentration in serum. Cerebrospinal fluid cpk concentration was significantly (P = 0.01) correlated to the number of rbc in csf. However, csf concentration of cpk was not significantly correlated to serum, blood, or csf variables evaluated.
Distribution of Luteinizing Hormone Releasing Hormone in the Canine Hypothalamus: Effect of Castration and Exogenous Gonadal Steroids
Authors: Kumar M. S. A. , Chen C. L. , Kalra S. P.
Published: February 2025

The effect of exogenous gonadal steroids or orchidectomy on the distribution and concentration of luteinizing hormone-releasing hormone (lhrh) in the hypothalamus of the dog was studied. Various hypothalamic areas of the canine brain were extracted with 90% methanol and processed, and lhrh was assayed, using a specific radioimmunoassay. The highest concentration of immunoreactive lhrh was found in the infundibular, premammillary, preoptic, and suprachiasmatic areas in intact male dogs and in anestrous female dogs. Measurable amounts of lhrh were found in the mammillary and lateral hypothalamic regions. The hypothalamus in the male dog had significantly (P < 0.05) higher lhrh concentrations 3 mm lateral to the midsagittal line (the lateral hypothalamic area) as compared with the area in the anestrous female dog.

Daily estrogen treatment of female dogs with 0.2 mg/day or 1 mg/day, im, or with testosterone propionate (1 mg/day, im) for 3 weeks increased lhrh concentrations 2.5- to 5-fold in the mammillary, premammillary, and infundibular areas and almost 40-fold in the preoptic, rostral commissural area and in the lateral and dorsal hypothalamic regions. Orchidectomy caused an increase in lhrh concentration in the preoptic and suprachiasmatic area with a concurrent decrease in lhrh in the infundibular area. Therefore, in the dog, lhrh is possibly synthesized or transported (or both) from different regions of the hypothalamus to the median eminence, and the gonadal steroid feedback mechanism is complex, involving multiple sites of action in the hypothalamus and the components of the limbic system.
Detection of Pseudorabies Virus Antibodies: Time of Appearance by Two Serotests
Authors: Haffer Keith , Gustafson D. P. , Kanitz C. L.
Published: February 2025

This report describes a time-course comparison of detection of pseudorabies virus antibodies in experimentally infected swine by the virus-neutralization (vn) and indirect hemagglutination tests. Specific antibody titers were observed by the iha test at 5 days after swine were inoculated, but not until 12 days by the vn test. The predominant immunoglobulin (Ig) class present in the serums of the swine at 5 and 7 days after inoculation was IgM, as determined by sulfhydryl reductions. The vn test lacked sensitivity to early Ig levels (IgM) in these experimentally infected swine, while the indirect hemagglutination test was highly sensitive to these same levels. On the basis of these results, it is possible that the vn test may read early infections as pseudorabies virus negative, due to the low presence of IgG in these samples.
Critical Tests of New Benzothiazole Anthelmintic Tioxidazole in the Horse
Authors: Drudge J. H. , Lyons E. T. , Tolliver S. C.
Published: February 2025

The basic-dose confirmation tests of tioxidazole for removal of susceptible populations of gastrointestinal parasites of the horse were made in 10 naturally infected horses, using the critical test method (experiment A). A single dose of tioxidazole, given at the rate of 11 mg/kg of body weight, was administered to 5 horses by stomach tube and to 5 horses by mixing the drug with the daily grain ration.

In the 5 horses given the drug by stomach tube, aggregate average removals were 90% or more for 5 horses infected with Strongylus vulgaris, 5 infected with S edentatus, 5 infected with small strongyles, 3 infected with Parascaris equorum, 3 infected with mature Oxyuris equi, and 5 infected with immature O equi. Bots (Gastrophilus intestinalis and G nasalis) in 5 infected horses and tapeworms (Anoplocephala perfoliata or A magna) in 3 infected horses were not removed. Activity against stomach worms (Trichostrongylus axei, Habronema muscae, and Draschia megastoma) was not evidenced.

In the 5 horses given the drug in the feed, aggregate average removals were 90% or more for 5 horses infected with S vulgaris, 5 infected with S edentatus, 1 infected with S equinus, 5 infected with small strongyles, 3 infected with P equorum, 3 infected with mature O equi, and 5 infected with immature O equi. Activity against bots, tapeworms, and stomach worms was not detected. Larval count data on fecal samples also indicated limited, if any, activity against Strongyloides westeri by tioxidazole at this dosage (11 mg/kg).

In addition to experiment A, tioxidazole (11 mg/kg) was administered via stomach tube in a single dose in a critical test to a foal naturally infected with benzimidazole-resistant small strongyles (population B) and removal was only 27% (experiment B). The same 5 species of small strongyles refractory to the benzimidazoles also exhibited resistance to tioxidazole. Specimens of P equorum and S vulgaris were all removed from the foal.

Untoward effects of tioxidazole treatment (11 mg/kg) were not observed in any of the animals.
Peripheral Serum Progesterone and Luteinizing Hormone Concentrations of Goats During Synchronization of Estrus and Ovulation with Prostaglandin F2α
Authors: Ott R. S. , Nelson D. R. , Hixon J. E.
Published: February 2025

Prostaglandin F2α (pgf2α) (2 doses, 11 days apart) was given to 20 mixed-breed dairy does to synchronize estrus and ovulation. The dose of pgf2α used was the free-acid equivalent of 8 mg which was divided between 2 injections at 0800 and 1200 hours. At the initiation of treatments, does were from day 0 (estrus) to day 18 of the estrous cycle. Seventeen of the does exhibited estrus within a mean (± se) interval of 53 ± 2 hours after the first 0800-hour injection. Peripheral progesterone concentrations determined at daily intervals indicated that pgf2α was luteolytic as early as day 4 of the cycle. Does were in the 8th to 12th days of the cycle at the time of the 2nd treatments with pgf2α. Estrus was observed in all 20 does at 50 ± 1 hour after the 0800-hour injections. Serum progesterone concentrations confirmed that luteolysis occurred in all of the does. In 19 does, concentrations of luteinizing hormone characteristic of a preovulatory peak were observed 55 ± 2 hours after the 2nd 0800-hour injection. One doe did not demonstrate a luteinizing hormone peak within the 72-hour period. Laparotomies were performed 6 days after estrus, and ovaries were examined for corpora lutea. The mean number of corpora lutea was 2.0 ± 1.0.