bluuebunny/crossref_metadata_2025_split huggingface dataset:
Digoxin Pharmacokinetics, Bioavailability, Efficacy, and Dosage Regimens in the Horse
Authors: Button C. , Gross D. R. , Johnston J. T. , Yakatan G. J. 
Published: February 2025

SUMMARY
The pharmacokinetics of iv administered digoxin and the bioavailability of intragastrically administered powdered digoxin tablets suspended in water were investigated in 6 clinically normal adult horses by 125I radioimmunoassay. The effect of 3 to 5 sequential iv doses of 5 μg of digoxin/kg of body weight at 2-hour intervals on a left ventricular index of contractility (Vmax) was assessed in 5 clinically normal horses. Standard pharmacokinetic equations and mean pharmacokinetic variables were used to derive parenteral and oral (loading and maintenance) doses for digoxin in horses. The calculated dosage regimens were administered and resulting plasma digoxin concentrations were monitored in 5 horses and 1 pony.
Digoxin disposition after iv injection was triexponential. A rapid distributive phase with a half life (t1/2 of 15 minutes was followed by a slow distributive phase with a t1/2 of 4.1 hours. The biological disposition t1/2 was 23.1 hours. The volume of distribution by extrapolation was 6.79 L/kg of body weight and 4.89 L/kg by the area method. The average bioavailability estimate for intragastrically administered digoxin was 19.2%. The Vmax increased significantly (P < 0.01) after iv digoxin administration. Greatest changes in Vmax were recorded after the first 2 injections (5 μg of digoxin/kg) corresponding to plasma digoxin concentrations of 0.83 and 1.68 ng/ml. Doses of digoxin were calculated as follows: iv loading 14, iv maintenance 7, oral loading 70, and oral maintenance 35 μg/kg/24 hours.
When these doses were given to a group of horses, plasma digoxin concentrations measured 12 and 24 hours after administration were mostly in the proposed therapeutic, nontoxic range of 0.5 to 2.0 ng/ml.
Antibody-Producing Cells in Bovine Lacteal Secretions After Local Immunization
Authors: Chang C. C. , Winter A. J. , Norcross N. L. 
Published: February 2025

SUMMARY
The indirect Jerne plaque assay was used to determine the presence of antibody-forming cells in lacteal secretions of 2 cows inoculated in the mammary gland with T4 phage. Two adjacent mammary glands of 2 nonlactating 7-months pregnant cows were inoculated by intramammary injection 4 times at 3- to 5-day intervals. The presence of plaque-forming cells (pfc) was assessed in each quarter beginning on postinoculation day 8 and at 4- to 14-day intervals thereafter. Amounts of antibodies in serum and secretions were measured by an indirect hemagglutination test.
The pfc were detected in secretions from all quarters of both cows between postinoculation days 8 and 32. Concentrations of pfc fluctuated within quarters during the course of the experiment but no relationship was evident between numbers of pfc in a quarter and its inoculation status. The use of monospecific antiglobulin sera at 1 sample-collection period revealed that cells synthesizing immunoglobulin (Ig)G and IgA antibodies were predominant in lacteal secretions. Antibody amounts in serum and secretions rose after inoculation, and titers in secretions were markedly higher in most instances.
Antibody-forming cells were thus demonstrated to accumulate in the mammary gland after intramammary inoculation. The presence of antibody-forming cells in noninoculated glands may have been the result of antigen transfer among quarters, but was considered more likely to have resulted from systemic migration of antigen-stimulated cells with migration into all quarters, regardless of inoculation status. Antibodies in lacteal secretions may have accumulated through a combination of local synthesis and selective transport from the bloodstream.
Effect of Local Immunization of the Mammary Gland on Phagocytosis and Intracellular Kill of Staphylococcus aureus by Polymorphonuclear Neutrophils
Authors: Guidry A. J. , Paape Μ. J. , Pearson R. E. , Williams W. F. 
Published: February 2025

SUMMARY
Four cows in the latter part of their 2nd, 3rd, or 4th lactations were immunized by multiple intramammary infusions of heat-killed Staphylococcus aureus in 2 quarters. The direct bactericidal effects of milk whey from the immunized and control quarters, before and after immunization, and the ability of these whey to support phagocytosis and intracellular kill were determined by incubating live S aureus with polymorphonuclear neutrophils isolated from milk. Immunoglobulins (Ig) were determined by single radial immunodiffusion. One immunized and 1 control quarter in each cow were challenge exposed with live S aureus and the courses of the infections were determined for 2 weeks.
There were significant cow differences in all Ig classes and in percentage of phagocytosis. Immunization resulted in a significant increase in IgA, IgG2, and IgM in the immunized quarters. Whey collected from immunized quarters supported phagocytosis of S aureus by isolated milk polymorphonuclear neutrophils significantly greater than did whey from control quarters. Extracellular live S aureus in the incubation medium was decreased by 59% in whey collected after immunization from immunized quarters. This decrease in extracellular S aureus was associated with a concomitant increase in total intracellular S aureus. However, intracellular live organisms showed no change. This lack of change indicated that the additional S aureus that were phagocytosed were killed. Direct bactericidal effects of whey were not observed. Intracellular live S aureus was not significantly correlated with any of the variables measured.
Scanning Electron Microscopy of Canine Pulmonary Arteries and Veins
Authors: Schaub Robert G. , Rawlings Clarence A. , Stewart Gwendolyn J. 
Published: February 2025

SUMMARY
In this communication we describe (1) a method for preparing pulmonary arteries and veins for examination by scanning electron microscopy and (2) the topographic characteristics of the luminal surface of these vessels. Seven healthy adult dogs were used in this study. The pulmonary vasculature was washed free of blood by perfusion with Tyrode's solution. Blood vessels were partially fixed in situ under physiologic pressure in 3 dogs (15 mm of Hg) or 2 times physiologic pressure in 4 dogs (30 mm of Hg) by perfusion with 1% glutaraldehyde. The pulmonary artery and aorta were tied off and the lungs were removed and immersed in 1% glutaraldehyde for 4 hours for additional fixation under pressure. Blood vessels were dissected free of surrounding tissue, further fixed in 2.5% glutaraldehyde, postfixed in osmium tetroxide, dehydrated, and critical point dried. The luminal surfaces were sufficiently flat to allow visualization of most of the topographic features of the luminal surface. Even 1 missing endothelial cell would have been obvious. Contrary to previous reports, we did not find a dense population of finger-like projections on the surface of arterial endothelium. Rather, we found a modest number of small rounded blebs. The venous endothelial sheet was similar in appearance. These observations demonstrate that scanning electron microscopy may be used to study vascular lesions in pulmonary vessels, as well as in more accessible peripheral vessels.
Effects of Ketamine HCl-Xylazine HCl Combination on Cardiovascular and Pulmonary Values of the Rhesus Macaque (Macaca mulatta)
Authors: Reutlinger Richard A. , Karl Alva A. , Vinal Steven I. , Nieser Mary Jo 
Published: February 2025

SUMMARY
Rhesus monkeys (Macaca mulatta) were anesthetized with 4% thiamylal sodium and then surgically prepared (instrumented) to record mean arterial blood pressure, heart rate, arterial Po2 and Pco2, venous Po2 and Pco2 and rectal temperature. Arterial blood pH and respiratory rate were manually recorded. Monkeys were placed in a restraint chair and allowed to regain full consciousness. A 30-minute base-line period was recorded and this was followed by an im injection of ketamine (7 mg/kg), xylazine (0.6 mg/kg), or ketamine-xylazine combination; the physiologic values were recorded for 255 minutes. Similar experiments conducted substituting saline solution for the drugs served as controls (saline control), with values recorded for 180 minutes.
When compared with one another, there was no significant difference of the 3 anesthetic regimens and saline control values with regard to (1) mean respiratory rate, (2) mean arterial pH, (3) mean arterial Po2, (4) mean arterial Pco2, or (5) mean venous Pco2. Statistically significant effects were expressed by the ketamine-xylazine combination and xylazine alone with regard to mean arterial blood pressure and heart rate. Both regimens exhibited an approximate 46% decrease (P < 0.05) in mean blood pressure and a 32% decrease (P < 0.01) in mean heart rate when compared with saline control and ketamine alone. These effects occurred within 30 minutes of injections being made and gradually returned toward but did not reach base-line values during the experimental period. When compared with control or ketamine values, ketamine-xylazine combination and xylazine significantly decreased mean rectal temperature. Statistically significant effects of the anesthetic agents on blood gases included a 28% maximum increase in venous Po2 at 30 minutes with ketamine, which gradually returned to normal over the 225-minute experimental period (P < 0.05 compared with saline control), and a 26% maximum decrease in venous Po2 at 30 minutes following ketamine-xylazine injection, which value remained depressed throughout the 225-minute experimental period (P < 0.05 compared with saline control).
The results indicate that although, clinically, the ketamine-xylazine combination appears to have offsetting pharmacologic effects, vital physiologic factors are being compromised for a long time.
An Age-Related Coagulation Disorder Associated with Experimental Infection with Infectious Bursal Disease Virus
Authors: Skeeles J. K. , Slavik Μ. , Beasley J. N. , Brown A. H. , Meinecke C. F. , Maruca S. , Welch S. 
Published: February 2025

SUMMARY
Specific-pathogen-free White Leghorn chickens were inoculated with a field strain of infectious bursal disease virus. One group (A) was inoculated at 17 days after the chicks were hatched, and the other groups (C and E) were inoculated at posthatch day 42. Blood samples were obtained for determination of clotting times (whole blood recalcification, prothrombin, and activated partial thromboplastin times), virus-neutralizing antibody, and total hemolytic complement. There were significant increases in clotting times for groups C and E at 3 and 5 days after they were inoculated. There were no significant increases in clotting times at 3 days after inoculation in the group A chickens (inoculated at 17 days after hatching). There were no significant decreases in total complement activity in any of these chickens (groups A, C, and E).
This study indicates that the mortality and clinical symptoms observed in chickens experimentally infected with infectious bursal disease virus may be associated with a clotting abnormality because it was noted only in chickens that developed severe clinical disease (inoculated at 42 days after hatching) and was not noted in chickens that remained clinically normal (inoculated at 17 days).
Collection and Processing of Blood Samples Dried on Paper for Microassay of Newcastle Disease Virus and Avian Influenza Virus Antibodies
Authors: Brugh Max , Beard C. W. 
Published: February 2025

SUMMARY
A practical method for collection and processing of dried whole blood samples on filter paper was developed to facilitate large-scale testing programs for Newcastle disease virus and avian influenza virus antibodies. A modified paper punch was used to cut and place dried blood samples simultaneously in a standard 96-well microplate for elution of antibody. Twelve eluted samples were simultaneously transferred to another microplate for the hemagglutination-inhibition (hi) microtest.
Similar hi titers were obtained with simultaneously collected serum and dried blood samples. Minor differences were not considered of practical importance in diagnostic serologic studies. Dried blood titers were not markedly affected by method of drying (37 C for 2 hours or 26 C for 4 hours), by storage for 24 hours before drying, or by storage of dried samples at 4 C for 28 days or 30 C for 14 days. Blood dried on paper was a satisfactory sample for assay of hi antibodies to Newcastle disease virus and avian influenza virus.
Serum Hydrocortisone (Cortisol) Values in Glaucomatous and Normotensive Beagles
Authors: Chen C. L. , Gelatt K. N. , Gum G. G. 
Published: February 2025

SUMMARY
Serum hydrocortisone (cortisol) values were measured by radioimmunoassay in 5 normotensive and 20 glaucomatous Beagles at 1 am, 7 am, 1 pm, and 7 pm. Significant differences (P < 0.01) in mean serum values of cortisol occurred between glaucomatous (20.9 ng/ml) and normotensive (9.5 ng/ml) Beagles. The slightly increased serum cortisol values in glaucomatous Beagles at 1 am and 7 am coincided with increases in intraocular pressure of glaucomatous Beagles. However, neither the normotensive nor glaucomatous Beagles exhibited any diurnal variations in serum cortisol values.
Collateral Arterial Blood Supply to the Normal and Ischemic Canine Kidney
Authors: Christie B. A. 
Published: February 2025

SUMMARY
Latex rubber was perfused into the abdominal aorta of 10 healthy dogs. Each kidney was found to have 4 to 6 vascular extensions of interlobar or arcuate arteries which communicated with an extrarenal artery. Renal collateral arterial connections were made with the phrenicoabdominal, spermatic, deep circumflex iliac, ureteral, caudal mesenteric, lumbar, and adrenal arteries.
The renal collateral circulation was stimulated in 4 dogs by gradual compression of the renal artery and the presence of hypertrophied vessels confirmed by angiography.
In 1 of these 4 dogs, the right renal artery was gradually compressed and finally occluded. Subsequently, contralateral nephrectomy was performed. Nine weeks later, the dog was still active, alert, and eating well.
Excretion of Mycobacterium avium from Lesions in the Intestine and Tonsils of Infected Swine
Authors: Ellsworth Steven , Kirkbride Clyde A. , Johnson Darrell D. 
Published: February 2025

SUMMARY
Five 8-week-old pigs were given an oral dose of approximately 108 viable units of Mycobacterium avium and confined in such a way as to prevent ingestion of fecal material. At necropsy 70 to 79 days later, there were granulomatous lesions, some containing acid-fast organisms, in the tonsils, aggregated lymphatic follicles (Peyer's patches) of the jejunum and ileum, mucosa of the caudal portion of the ileum, ileocecal valve, and cecum. The organism was isolated from tonsils, intestine, and swabs from the surface of some of these tissues. Mycobacterium avium that apparently originated from lesions in the pigs was first detected in the feces 20 to 23 days after the animals were inoculated. The number of organisms excreted began to decrease at 55 days, and none was isolated from feces at 69 days. It was concluded that lesions in the intestine and possibly the tonsils were the sources of the organisms in the feces. The role of tonsil and intestine lesions of swine as sources of perpetual herd infections is discussed.
Serum Complement Activity of Protein-Energy Malnourished Beef Cows
Authors: Woodard L. F. , Eckblad W. P. , Olson D. P. , Bull R. C. , Everson D. O. 
Published: February 2025

SUMMARY
Beef heifers were fed protein- or energy-deficient rations (or both) for approximately the last 5 months of pregnancy. Serum samples were periodically collected and were analyzed for amounts of total complement (C) hemolytic activity. After being fed the rations for approximately 2 months, heifers given low-energy rations had significantly lower (P < 0.01) amounts of C than did those fed adequate energy rations. This decrease in C was observed regardless of the amount of dietary protein, although low protein intake seemed to exaggerate the effect of low energy consumption. Reduced protein in the rations had no effect on C titers when caloric intake was adequate. Also, the depressive effect of low dietary energy on C values was no longer apparent after approximately 4 months of feeding the rations. Amounts of C dropped by 20 to 40 U for all groups at or near the time of parturition. The C values averaged over all test dates were significantly lower (P < 0.05) for those heifers given low energy in their rations as compared with values for heifers fed adequate energy rations (146.9 vs 160.8 U).
Pathogenesis of Rotaviral Enteritis in Gnotobiotic Pigs: A Microscopic Study
Authors: McAdaragh J. P. , Bergeland Μ. E. , Meyer R. C. , Johnshoy Μ. W. , Stotz I. J. , Benfield D. A. , Hammer R. 
Published: February 2025

SUMMARY
The pathogenesis of rotavirus (rv) infection was studied in gnotobiotic pigs orally inoculated with a field isolate of porcine rotavirus. Virus-intestinal cell interactions were examined by fluorescent antibody technique, light microscopy, and scanning and transmission electron microscopy. Clinical signs of diarrhea were observed in inoculated pigs at postinoculation hours (pih) 12 through 96. Examination of negative-stained fecal preparations revealed large numbers of coreless rotaviral particles in fecal material collected at pih 24 to 72, whereas nearly 100% of the virus particles were complete in fecal samples collected at pih 96. Specific fluorescence was observed in the cytoplasm of a few villous absorptive cells in the duodenum and upper portion of the jejunum (uj) at pih 12 with the most intense fluorescence at pih 24 to 96 in the absorptive cells of villi in the uj through the midportion of the small intestine. Virus replication resulted in desquamation of villous absorptive cells in the lower portion of the jejunum (lj) through the upper portion of the ileum (ui) beginning at pih 24. In the uj through the ui, the loss of villous absorptive cells resulted in a progressively shortened villi beginning at pih 24 and was most severe in inoculated pigs killed at pih 72 to 84. Crypt hyperplasia was observed in the uj through the ui at pih 60 to 96, resulting in replacement of villous absorptive cells, as evidenced by an increase in cuboidal villous epithelial cells present at pih 72 to 96 and an apparent increase in the length of villi at pih 96.
Segments of the small intestine examined by scanning electron microscopy revealed villous fusion, rounded absorptive cells, villous atrophy, and exposure of the lamina propria especially in the lj through the ui. Thin sections of the small intestine examined by transmission electron microscopy revealed rv particles in the absorptive cells of the midportion of the small intestine and duodenum through the ui at pih 12 and 24, respectively. Cytoplasmic lysis of absorptive epithelial cells was evident at pih 36, and viral particles were observed in the lumen near microvilli. Rotavirus-induced changes in the small intestine of gnotobiotic pigs were characteristic of those described for natural rv infection.
Effect of Cholecystokinin, Secretin, Glucagon, and Insulin on Gastric Emptying and Acid Secretion in the Calf
Authors: McLeay L. Μ. , Bell F. R. 
Published: February 2025

SUMMARY
The effect of iv infusion of secretin, cholecystokinin (cck), glucagon, and insulin on the gastric electromyogram (emg), gastric emptying, and gastric acid secretion during a saline test meal was studied in milk-fed calves. Secretin (1 U/kg of body weight/hr) and glucagon (5 μg/kg/hr) reduced the incidence of antral action potentials, slowed gastric emptying, and reduced gastric acid secretion. The cck (0.5 to 4 U/kg/hr) reduced the incidence of (at lower doses) and abolished (at higher doses) antral action potentials, inhibited gastric emptying, but increased gastric acid secretion. Insulin (1 U/kg/hr) at first reduced gastric emg activity in abomasal body and antrum, and diminished gastric emptying and acid secretion; however, greater secondary excitatory effects on the emg and marked emptying developed 30 to 35 minutes later and were attributed to hypoglycemic vagal excitation. In the calf, secretin and glucagon are inhibitory to gastric function, but cck, although it is inhibitory to gastric emptying, is an agonist to gastric acid secretion.
Bovine Mammary Gland Macrophage: Isolation, Morphologic Features, and Cytophilic Immunoglobulins
Authors: Desiderio J. V. , Campbell S. G. 
Published: February 2025

SUMMARY
Macrophages can be obtained easily and in large numbers from the involuted mammary gland of the cow without the use of stimulating agents. Daily injection of sterile isotonic saline solution into 1 quarter of the udder resulted in a gradual change of the resident cell population. After approximately 1 week, the macrophage was the predominant cell type present.
Upon initial harvesting, macrophages were round with a cell diameter of 30 to 40 μm. Through adherence to glass and subsequent washings, monolayers were obtained consisting of 95% to 99% macrophages. By 24 hours of culture in vitro, macrophages underwent a substantial change in general morphologic features, involving the reorganization of intercellular structures and the development of cytoplasmic processes.
Bovine immunoglobulins (Ig) of the IgG1 and IgG2 subclasses were both shown to be cytophilic for bovine mammary gland macrophages in vitro, although IgG2 was considerably more so.
Bovine Mammary Gland Macrophage: Effects of Colostral Components on Phagocytosis
Authors: Desiderio J. V. , Campbell S. G. 
Published: February 2025

SUMMARY
The interaction of bovine mammary gland macrophages with components of bovine colostrum was shown to have considerable influence on phagocytosis of Escherichia coli 078K80. Colostrum appeared to contain specific and nonspecific factors which affect the macrophage, as well as the target bacteria.
Neutrophil Leukocyte as a Source of Lactoferrin in Bovine Milk
Authors: Harmon R. J. , Newbould F. H. S. 
Published: February 2025

SUMMARY
The lactoferrin (lf) concentration of bovine blood and milk neutrophilic polymorphonuclear leukocytes (pmn) was determined and an estimate made of the pmn contribution to the elevated lf concentrations in milk during inflammation of the mammary gland. The mean blood and milk pmn concentrations of lf were 8.63 and 2.98 μg/106 pmn, respectively. It was suggested that this difference may be due to the phagocytosis of fat and degranulation by milk pmn, causing lf release. The results of immunoperoxidase staining of blood leukocytes indicated that lf was found only in pmn as no lf was detectable in bovine eosinophils, lymphocytes, or monocytes. Staining for lf appeared to be limited to the cytoplasm.
Increases in lf values in milk during endotoxin-induced mammary gland inflammation were preceded by increased somatic cell counts (94% pmn). It was estimated that an average of 4.9% of the peak lf levels in whey could have come from the pmn, suggesting this cell is not the major source of lf in milk during mastitis.