bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of constant administration of a gonadotropin-releasing hormone agonist on reproductive activity in mares: Induction of ovulation during seasonal anestrus
Authors: Fitzgerald Barry P. , Meyer Steven L. , Affleck Karen J. , Silvia Pamela J. 
Published: January 2024

Summary
The potential of a gonadotropin-releasing hormone (GnRH) agonist (goserelin acetate), delivered constantly for 28 days via a subcutaneous depot, to induce ovulation in seasonally anestrous mares, was investigated. Two experiments were conducted, in which a range of doses (30 to 240 µg/mare/d) was examined. Mares were selected on the basis of lack of substantial follicular development (follicle diameter < 20 mm determined ultrasonically) and low serum concentrations of luteinizing hormone (lh) and progesterone.
Constant administration of the GnRH agonist-induced ovulation in anestrous mares, but a dose-response relation was not observed. Furthermore, with identical doses tested in consecutive or alternate years, considerable variation was observed in the ovulatory response. In general, ovulation in all treated mares was accompanied by increased circulating concentrations of lh and a decrease in follicle-stimulating hormone values. Ovulation was preceded by an increase in estradiol and lh concentrations. In mares in which ovulation did not occur, concentration of lh increased during agonist treatment, whereas that of follicle-stimulating hormone either increased or did not change.
It was concluded that constant administration of GnRH agonists may induce ovulation in mares during seasonal anestrus; however, percentage of mares ovulating and the lack of reproducibility of effect indicate that this approach is inappropriate for use as a reliable method to manipulate breeding activity in commercial broodmares.
Brain stem auditory evoked potentials from bone stimulation in dogs
Authors: Strain George M. , Green Kelly D. , Twedt Alan C. , Tedford Bruce L. 
Published: January 2024

Summary
Brain stem auditory evoked potential (baep) testing with air-conducted click stimuli can be used to diagnose sensorineural deafness in dogs if conductive deafness can be ruled out. Detection of conductive deafness can be performed by recording baep elicited by a vibratory stimulus transducer placed against the skull. Air- and bone-conducted baep were compared in dogs, varying bone stimulator placement, click polarity, and stimulus intensity. Optimal bone stimulator placement was determined to be over the mastoid process, followed by the mandible and the zygomatic arch. Condensation polarity clicks gave responses preferable to those elicited by rarefaction or alternating polarity. Bone-conducted baep peak latencies were significantly longer than air-conducted latencies after correction of the latencies for the air conduction time accompanying air-conducted stimuli. Significant differences between stimulus modalities were not seen for baep peak amplitudes or interpeak latencies. Latency-intensity and amplitude-intensity regressions had similar effects for both modalities: latencies decreased and amplitudes increased as stimulus intensity increased.
Ultrasound-guided brain biopsy in dogs
Authors: Thomas William B. , Sorjonen Donald C. , Hudson Judith A. , Cox Nancy R. 
Published: January 2024

Summary
Ultrasound-guided brain biopsy of the cingulate gyrus and the head of the caudate nucleus was performed in clinically normal dogs. Dogs survived the surgery, and neurologic deficits were not detected in the 14-day postoperative period. Magnetic resonance imaging detected changes in the brain associated with biopsy in 9 dogs (90%) immediately after surgery and in 6 dogs (60%) 14 days after surgery. Fourteen days after surgery, sonography of the brain, performed through the skin overlying the burr hole, detected changes associated with biopsy in 9 dogs (90%). Histopathologic changes evident in the brain 14 days after surgery consisted of focal malacia and hemorrhage with associated subacute encephalomeningitis. Postmortem examination indicated that the biopsy specimen was accurately obtained from the desired site in 9 dogs (90%). Tissue specimens suitable for histologic examination were obtained from 10 dogs (100%). Accuracy and low morbidity of ultrasound-guided biopsy indicate that this may be a useful technique for diagnosis of focal brain disease in dogs.
Colorectal blood supply in dogs
Authors: Goldsmid S. E. , Bellenger C. R. , Hopwood P. R. , Rothwell J. T. 
Published: January 2024

Summary
To determine blood supply in the area, dye or radioopaque contrast material was injected into the named arteries supplying the terminal colon and recturn in 10 dogs. The cranial rectal artery appeared to supply most of the blood to the terminal colon and rectum. The middle and caudal rectal arteries supplied variable and relatively insignificant amounts. The intrapelvic rectum had a less adequate blood supply than did the terminal colon or proximal rectum.
A ventral midline laparotomy and pubic osteotomy were performed in an additional 11 dogs to provide access to the terminal colon and rectum. When the cranial rectal artery was ligated and the coloreetal junction was transected and anastomosed, the intrapelvic rectum developed marked congestion, edema, and discoloration. Rectal fluorescence, after iv administration of fluorescein, was either poor or absent. Histologically, partial- to full-thickness mucosai necrosis was evident in most tissue specimens taken from the rectum, and muscle necrosis was evident in some.
These findings suggest that, in dogs, the cranial rectal artery should be preserved if at all possible and, if the cranial rectal artery is ligated, most of the intrapelvic rectum should be resected to ensure adequate blood supply to the anastomosis.
Toxicity of desoxycorticosterone pivalate given at high dosages to clinically normal Beagles for six months
Authors: Chow Edward , Campbell William R. , Turnier John C. , Lynn Randy C. , Pavkov Kenneth L. 
Published: January 2024

Summary
Desoxycorticosterone pivalate was administered im to juvenile Beagles at 0, 2.2, 6.6, or 11 mg/kg of body weight daily over a consecutive 3-day period every 28 days (equivalent to a cumulative monthly dosage of 0, 6.6, 19.8, or 33 mg/kg) for 6 months. Polyuria, polydipsia, and decreases in serum potassium and bun concentrations were detected while the dogs were being treated. Transient increases in serum sodium concentrations also were detected. The treated males had significant decreases in body weight gain, resulting in an 18% decrease in body weight in the 11-mg/kg dosage group, compared with the controls. The weights of the adrenal glands, epididymides, and testes also were lower in the treated males. Organ weights for the 2.2, 6.6, and 11-mg/kg dosage groups were: 86, 79, and 69%, respectively, of the controls (adrenal glands); 80, 70, and 68%, respectively, of the controls (epididymides); and, 79, 75, and 67%, respectively, of the controls (testes). When normalized to body weight, these decreases in organ weight were still dosage-dependent, but the differences were less remarkable. In contrast, the relative weight (to body weight) of the kidneys (males and females) and of the thyroid and parathyroid glands (males) were higher dosage-dependently. All of the treatment-related effects, other than organ and body weight changes, appeared to be reversible following the cessation of treatment. On the basis of these results, it was concluded that treatment with desoxycorticosterone pivalate could be tolerated, even when given at dosages 15-fold the therapeutic dosage of 2.2 mg/kg every 25 days.
Radiographie study of homotypic variation of long bones in dogs
Authors: Markel Mark D. , Sielman Emily 
Published: January 2024

Summary
Dogs have been used extensively as an experimental model for studying musculoskeletal disorders. Many of these studies incorporated sequential radiography to quantitate a particular treatment's effect, using the contralateral bone as the control condition. The contralateral bone can be used as a control only if there is bilateral symmetry between right and left limbs. We performed radiography (craniocaudal and lateromedial views) on 10 pairs of humeri, radii, femora, and tibiae from dogs, using an alignment jig, to radiographically determine homotypic geometric variations or long bones. The bones were divided into 5 regions: proximal epiphysis, proximal metaphysis, diaphysis, distal metaphysis, and distal epiphysis. The toal bone diameter, medullary diameter, and cortical width (total of medial + lateral cortex or total of cranial + caudal cortex) were measured at specified slices throughout each of these regions. Fourteen of 540 homotypic comparisons revealed significant differences between right and left bones at either a slice or region. Although there were only 14 significant differences between right and left bones at any region or slice, measurements were more precise with lower coefficients of variation in the diaphyseal and epiphyseal regions. Homotypic differences in diaphyseal and epiphyseal regions were < 5.3 and 7.5%, respectively (power = 0.8). In metaphyseal regions, however, homotypic differences were larger; these differences could have been as large as 11.5% for total bone diameter, 15.6% for medullary diameter, and 80.0% for cortical width without achieving significant differences between populations (power = 0.8). This study validated the concept of using the contralateral limb as the control condition in orthopedic studies using dogs, particularly when evaluating the geometric properties of long bones radiographically.
Specific expression of cellular oncogenes c-myc and c-myb in T-cell lines established from three types of bovine lymphosarcomas
Authors: Ishiguro Naotaka , Matsui Takane , Shinagawa Morikazu 
Published: January 2024

Summary
Expression of cellular oncogenes in 3 lymphoid cell lines, BTL-PC3 (BoCD2−, BoCD4−, BoCD8−, BoWC1+), BLS1 (BoCD2+, BoCD4−, BoCD8−, B0WC1+) and BLT2 (BoCD2−, BoCD4−, BoCD8−, BoWC1−), which have been established from calf, skin, and thymic types of lymphosarcomas, respectively, were analyzed by dna-rna (northern blot) hybridization. To determine specific expression of oncogenes involved in malignant transformation of the lymphoid cells, cellular rna was isolated from bovine tumor cell lines, BTL-PC3, BLS1, and BLT2, and from Madin Darby bovine kidney cells used as a control for bovine cell lines. The rna was hybridized against 5 viral oncogene probes (v-jun, v-myc, v-erbB, v-erbA and v-fes), 6 human cellular oncogene probes (N-ras, c-Blym-1 c-erbB-2, c-fos, c-myb and c-abl), human p53 tumor suppressor gene, and bovine LDH-A gene probes. Line BTL-PC3 expressed 2.4-kilobase (kb) c-myc and 4.0- and 3.6-kb c-myb transcripts, and line BLT2 expressed a 3.8-kb c-myb transcript, but line BLS1 expressed no message for the oncogenes tested. Specific transcripts of p53 were found in BTL-PC3 and BLT2 lines, but not in BLS1. Madin Darby bovine kidney cell line expressed multiple cellular oncogenes, c-jun, c-myc, and c-fos, and p53 genes. Southern blot hybridization did not reveal abnormal dna rearrangements associated with the expressed oncogenes (c-myc and c-myb) in the 3 bovine tumor lines. From these results and the immunophenotype of the lymphoid cells, it appeared that c-myb specific mRNA were transcribed more often in immature bovine leukemia T cells (calf and thymic types) than in mature T cells from the skin type.
Assembly pathway of avian infectious laryngotracheitis virus
Authors: Guo Peixuan , Scholz Elke , Turek John , Nodgreen Robert , Maloney Bryan 
Published: January 2024

Summary
Infectious laryngotracheitis virus (iltv) is the causative agent of a highly contagious upper respiratory tract infection in chickens. At present, iltv vaccines are not satisfactory because of development of a latent carrier status in vaccinated birds. Development of recombinant virus vaccines has been hampered by the limited information available on the molecular level and organization of this virus. We isolated 3 assembly intermediates, designated A, B, and C from iltv-infected cells. Analysis of [3H] thymidine- and [35S]methionine-labeled particles, and electron microscopic studies indicated that particle A was the empty capsid, particle B was the procapsid containing scaffolding protein, and particle C was the dna-filled capsid. The iltv procapsids could only be found in the nucleus, which indicated that procapsids could not translocate through the nuclear membrane until they packaged the dna. The dna-filled capsids migrated through the nuclear membrane and obtained an envelope from the inner membrane of the nucleus. The enveloped particles then migrated through the lumen of the endoplasmic reticulum into vacuoles in the cytoplasm. Infective virions were isolated from within the infected cells, indicating that budding through the cytoplasmic membrane is not a necessary step in iltv maturation. Abundant arrays composed of tubules about 45 to 50 nm wide were found in the cytoplasm of chicken embryonic liver cells about 30 to 38 hours after infection. Comparison of the assembly intermediates and the dna packaging pathway of iltv with that of bacteriophage ϕ29 indicates that similarity exists. A model for the pathway of iltv assembly is proposed.
Cardiopulmonary and behavioral responses to computer-driven infusion of detomidine in standing horses
Authors: Daunt David A. , Dunlop Colin I. , Chapman Phillip L. , Shafer Steven L. , Ruskoaho Heikki , Vakkuri Olli , Hodgson David S. , Tyler Liz M. , Maze Mervyn 
Published: January 2024

Summary
Cardiopulmonary and behavioral responses to detomidine, a potent α2-adrenergic agonist, were determined at 4 plasma concentrations in standing horses. After instrumentation and baseline measurements in 7 horses (X̄ ± sd for age and body weight, 6 ± 2 years, and 531 ± 48.5 kg, respectively), detomidine was infused to maintain 4 plasma concentrations: 2.1 ± 0.5 (infusion 1), 7.2 ± 3.5 (infusion 2), 19.1 ± 5.1. (infusion 3), and 42.9 ± 10 (infusion 4) ng/ml, by use of a computer-controlled infusion system.
Detomidine caused concentration-dependent sedation and somnolence. These effects were profound during infusions 3 and 4, in which marked head ptosis developed and all horses leaned heavily on the bars of the restraining stocks. Heart rate and cardiac index decreased from baseline measurements (42 ± 7 beats/min, 65 ± 11 ml·kg of body weight−1·min−1) in linear relationship with the logarithm of plasma detomidine concentration (ie, heart rate = −4.7 [loge detomidine concentration] + 44.3, P < 0.01; cardiac index = −10.5 [loge detomidine concentration] + 73.6, P < 0.01). Second-degree atrioventricular block developed in 5 of 7 horses during infusion 3, and in 6 of 7 horses during infusion 4. Mean arterial blood pressure increased significantly from 118 ± 11 mm of Hg at baseline to 146 ± 27 mm of Hg at infusion 4. Similar responses were observed for mean pulmonary artery and right atrial pressures. Systemic vascular resistance (baseline, 182 ± 28 mm of Hg·ml−1·min−1·kg−1) increased significantly during infusions 3 and 4 (to 294 ± 79 and 380 + 58, respectively). Plasma atrial natriuretic peptide concentration was significantly increased with increasing detomidine concentration (20.4 ± 3.8 pg/ml at baseline to 33.5 ± 9.1 at infusion 4). There were few significant changes in respiration rate and arterial blood gas and pH values. We conclude that maintenance of steady-state detomidine plasma concentrations resulted in cardiopulmonary changes that were quantitatively similar to those induced by detomidine bolus administration in horses.
Kinetic analysis of D-xylose absorption after its intragastric administration to mares deprived of food
Authors: Ferrante Pamela L. , Freeman David E. , Ramberg Charles F. , Kronfeld David S. 
Published: January 2024

Summary
Multicompartmental analysis was applied to study the kinetics of D-xylose distribution after its intragastric administration to healthy mares deprived of food for 12, 36, 72, and 96 hours. Disposition of D-xylose was described by a 5-compartment model. Maximal plasma D-xylose concentration was similar for 12 and 36 hours of food deprivation and was greater (P = 0.0001) than the values for 72 and 96 hours. Peak concentration of D-xylose appeared progressively later as food deprivation proceeded (P = 0.0001). Fractional rate of transfer (k1,6) was less after 96 hours of food deprivation, compared with 12 hours (P = 0.0001), and percentage of D-xylose absorbed was reduced (P = 0.0441) after food deprivation. Fractional rate of transfer (k6,5), representing gastric emptying, tended to progressively decrease with food deprivation.
Results indicated that formal kinetic analysis can be applied to D-xylose absorption kinetics in horses. Reduction in the extent of D-xylose absorption after food deprivation may be partly caused by decreased rate of D-xylose absorption across the small intestinal mucosa, but other factors, such as gastric emptying and nonabsorptive losses, may also be involved.
Alterations in the arrhythmogenic dose of epinephrine after xylazine or medetomidine administration in isoflurane-anesthetized dogs
Authors: Lemke Kip A. , Tranquilli William J. , Thurmon John C. , Benson G. John , Olson William A. 
Published: January 2024

Summary
Eight dogs (body weight, 12.5 to 21.5 kg) were assigned at random to each of 3 treatment groups (is, ix, im) that were not given glycopyrrolate and to each of 3 groups that were given glycopyrrolate (igs, igx, igm). Dogs were anesthetized with isoflurane (1.95% end-tidal concentration), and ventilation was controlled (PCO2, 35 to 40 mm of Hg end-tidal concentration). Glycopyrrolate was administered iv and im at a dosage of 11 μg/kg of body weight, each. Saline solution, xylazine (1.1 mg/kg, im), or medetomidine (15 μg/kg, im) was administered 10 minutes after baseline ade determination. Redetermination of the ade at the same infusion rate was started 10 minutes after drug administration. Arrhythmogenic dose was determined by constant infusion of epinephrine at rates of 1.0, 2.5, and 5.0 μg/kg/min. The ade was defined as the total dose of epinephrine that induced at least 4 ectopic ventricular depolarizations within 15 seconds during a 3-minute infusion, or within 1 minute after the end of the infusion. Total dose was calculated as the product of infusion rate and time to arrhythmia. Statistical analysis of the differences between baseline and treatment ade values was performed by use of one-way anova. Mean ± sem baseline ade values for groups is, ix, and im were 1.55 ± 0.23, 161 ± 0.28, and 1.95 ± 0.65 μg/kg, respectively. Differences for groups is, ix, and im were – 0.12 ± 0.05, – O.31 ± 0.40, and – 0.17 ± 0.26, respectively. Differences for groups igs, igx, and igm could not be calculated because arrhythmias satisfying the ade criteria were not observed at the maximal infusion rate of 5.0 μg/kg/min. Differences among groups is, ix, and im were not significant. We conclude that in isoflurane-anesthetized dogs: preanesthetic dosages of xylazine (1.1 mg/kg, im) or medetomidine (15 μg/kg, im) do not enhance arrhythmogenicity, and at these dosages, there is no difference in the arrhythmogenic potential of either α2-adrenergic receptor agonist.
Safety of albendazole in developing bovine fetuses
Authors: Theodorides Vassilios J. , Carakostas Michael C. , Colaianne James J. , Freeman John F. , Page Stephen W. 
Published: January 2024

Summary
Albendazole, administered orally at a dose rate of 25 mg/kg of body weight to presumed pregnant cows or heifers on days 21, 31, 41, 51, and 61 of gestation, did not induce toxicosis in embryos or fetuses, and all calves born were structurally normal. Albendazole administration at a rate of 25 mg/kg to cows at 7 and/or 14 days of gestation decreased the apparent conception rate (ie, embryolethality), but did not have a teratogenic effect. Apparent embryolethality was greater in cows administered 25 mg/kg only on day 14, compared with those administered the drug only on day 7. Single dosage of 25 mg/kg given in the final 3 months of gestation did not induce abortion. There were no adverse effects of albendazole at a dosage of 10 or 15 mg/kg on developing embryos or fetuses when administered to presumed pregnant cows at various times in early gestation.
Mechanism of hemolysis of canine erythrocytes induced by L-sorbose
Authors: Goto Ikuo , Inaba Mutsumi , Shimizu Toshio , Maede Yoshimitsu 
Published: January 2024

Summary
The cause of species difference in the susceptibility of erythrocytes to L-sorbose, and the difference in the hemolytic effect of sorbose on high potassium-containing (hk) and low potassium-containing (lk) canine erythrocytes were examined. L-Sorbose was phosphorylated in canine erythrocytes, but not in human erythrocytes. Furthermore, sorbose-1-phosphate, a metabolite of L-sorbose, strongly inhibited the hexokinase of lk canine erythrocytes, but not that of hk canine erythrocytes. These results strongly indicated that inhibition of hexokinase by sorbose-1-phosphate in lk erythrocytes induced severe glycolytic limitation in these cells, resulting in hemolysis, and that hk erythrocytes are resistant to sorbose-induced hemolysis because these cells have a high hexokinase activity.
Alterations in blood viscosity in horses competing in cross country jumping
Authors: Sommardabl Carla S. , Andrews Frank M. , Saxton Arnold M. , Geiser Dennis R. , Maykuth Patricia L. 
Published: January 2024

Summary
Packed cell volume and plasma total protein (tp), serum albumin (Alb) and globulin (Glb), and plasma ionized calcium (PCa) concentrations, blood viscosity (bv), and plasma viscosity (pv) were measured in 42 horses at rest and after the cross country jumping phase of a horse trial competition. The bv and pv were determined at 6 shear rates (230, 115, 46, 23, 11.5, 5.75 s−1), using a digital rotational cone and plate microviscometer. A paired t-test was used to determine differences between pcv, tp, Alb, Glb and PCa values at rest and after exercise. The pcv, tp, Alb, and Glb values increased (P < 0.05) in horses after exercise. The PCa concentration decreased (P < 0.05) in horses after exercise. Mean bv and pv in the 42 horses at rest and after exercise were fitted to an asymptotic function. Significant (P < 0.05) correlation at all shear rates was seen between bv at rest and pcv, tp, Alb, Glb, and PCa values at rest; and between bv after exercise and pcv, tp, Alb, Glb, and PCa values after exercise. Significant correlation was not seen between pv at rest and tp, Alb, Glb, and PCa at rest, or between pv after exercise and tp, Alb, Glb, and PCa concentrations after exercise at any shear rate.