bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of glomerular lesions in dogs with acute experimentally induced Ehrlichia canis infection
Authors: Codner E. C. , Caceci T. , Saunders G. K. , Smith C. A. , Robertson J. L. , Martin R. A. , Troy G. C.
Published: January 2024

Six male Beagles were inoculated with Ehrlichia canis. Transient proteinuria was confirmed during the acute phase of infection by serial determination of urinary protein-to-creatinine ratio. Peak urine protein loss, consisting principally of albumin, was observed 2.5 to 3.5 weeks after inoculation. Renal biopsy specimens were obtained before inoculation, during peak proteinuria, and 10 weeks after inoculation when proteinuria had resolved. Renal tissue was evaluated by use of light, immunofluorescent, and electron microscopy to correlate specific glomerular lesions with development of proteinuria.

Histologic examination revealed perivenular and interstitial infiltrates of lymphocytes and plasma cells localized principally to the renal cortex. Glomerular lesions were minimal to absent. Immunofluorescent staining revealed moderate to marked deposition of anti-canine IgG and IgM in the glomerular tufts and mesangium. Depositions of anti-canine complement factor C3 were not observed. Immunofluorescent staining persisted 10 weeks after inoculation, despite resolution of proteinuria, and probably represented passive trapping of immunoglobulins.

Ultrastructural examination revealed fusion of podocyte processes that coincided with development of proteinuria. Electron-dense deposits or changes in the basement membrane were not observed. Morphometric measurements of average podocyte process length and percentage of coverage of basement membrane by podocyte processes were used to quantify the degree of process fusion. Both measurements increased significantly (P < 0.05) during peak proteinuria, and returned to preinoculation values when proteinuria had resolved 10 weeks after E canis inoculation.

These findings indicated possible minimal-change glomerulopathy, rather than immune-complex glomerulonephritis, during acute E canis infection and could explain transient proteinuria without histologic evidence of glomerular disease.
Pharmacokinetics of clindamycin phosphate in dogs after single intravenous and intramuscular administrations
Authors: Budsberg Steuen C. , Kemp Douglas T. , Wolski Nancy
Published: January 2024

Clindamycin phosphate was administered to dogs at dosage of 11 mg/kg of body weight via iv and im routes. The disposition curve for iv administration was best represented as a 2-compartment open model. Mean elimination half life was 194.6 ± 24.5 minutes for iv administration and 234.8 ± 27.3 minutes for im administration. Bioavailability after im administration was 87%. Dosage of 11 mg/kg, iv, given every 8 hours, provided serum concentration of clindamycin that exceeded the minimal inhibitory concentration for all Staphylococcus spp, as well as most pathogenic anaerobes, throughout the dosing interval. Intramuscular administration induced signs of pain and cannot be recommended.
Regulation of adrenocorticotropin secretion from cultured canine anterior pituitary cells
Authors: Kemppainen R. J. , Clark T. P. , Sartin J. L. , Zerbe C. A.
Published: January 2024

Pituitary cells, collected from five healthy dogs, were cultured and treated with various doses of ovine corticotropin-releasing hormone (crh), arginine vasopressin (avp), oxytocin (ot), or angiotensin II (aii) to determine which of these hypothalamic peptides affected adrenocorticotropin (acth) secretion. Of the 4 peptides, only crh significantly increased acth secretion from cultured canine anterior pituitary cells. The lowest dose of crh tested, 0.01 nM, significantly stimulated acth release. Co-addition of avp, ot, or aii with crh did not increase acth secretion beyond that caused by addition of crh alone. Similarly, neither co-addition of avp with ot, avp with aii, or ot with aii significantly stimulated acth secretion. These results support a role for crh in the physiologic regulation of acth secretion from the canine anterior pituitary, but do not support regulatory roles for avp, ot, or aii.
Collection of pancreatic exocrine secretions by formation of a duodenal pouch in cattle
Authors: St-Jean G. , Harmon D. L. , Peters J. P. , Ames N. K.
Published: January 2024

Collection of exocrine pancreatic secretions from cattle by use of a single-unit cannula was performed. The major advantage of the cannula was simple technical management. A small pouch of the duodenum into which the major pancreatic duct drains was formed. Continuity of the duodenum was reestablished by end-to-end anastomosis. A side arm of the cannula was inserted into the pouch to collect exocrine secretions, and the main portion of the cannula was placed cranial to the anastomosis to return pancreatic secretions to the small intestine between collection periods. The accessory pancreatic duct was ligated in 2 of 4 cattle to evaluate possible secretory contribution from this source.

All cattle remained healthy after cannulation, and cattle gained approximately 100 kg of body weight in the 5 months after surgery. The mean secretory rate for exocrine pancreatic secretion in cattle was 106 ± 6.8 ml/h. There was no effect of feeding on the pattern of secretion nor were there significant differences between cattle, A fistula formed between the pouch and duodenum approximately 120 days after surgery in the first 2 cattle used. Development of fistulas was prevented for 300 days in subsequently prepared cattle by use of surgical mesh around the cannulas, leading to functional cannulation sites. Preparation of a duodenal pouch appeared useful for long-term studies of pancreatic exocrine secretion in cattle.
Use of computerized interactive morphometry in the diagnosis of mammary adenoma and adenocarcinoma in dogs
Authors: Ciurea Doina , Wilkins Robert J. , Shalev Moshe , Liu Zhiyuan , Barba Joseph , Gil Joan
Published: January 2024

We attempted to define quantitative objective criteria for diagnosis of mammary adenoma and adenocarcinoma in dogs. To that end, correlation between diagnosis made by conventional histologic examination and morphometric descriptors, obtained by computerized histologic analysis, was assessed in biopsy specimens of mammary tissue from 63 dogs. We used 2 interactive computer procedures: one assessed mean nuclear perimeter, mean nuclear area, and circularity factor; and the other evaluated nuclear stratification and cell crowding. A data base was generated with 11 specimens from normal mammary tissue, 17 specimens from mammary adenoma, 18 specimens from low-grade mammary adenocarcinoma, and 15 specimens from mammary adenocarcinoma. The mean values of nuclear perimeter, nuclear area, nuclei per millimeter of basement membrane, and minimal distances from cells to basement membrane gradually increased from normal to high-grade malignancy. Distributions of nuclear areas and of minimal distances from cells to basement membrane were shifted in specimens from malignant tumors. Multivariate analysis confirmed the homogeneity of the diagnostic groups.
Effect of intravenous and aerosol administration of 5-hydroxytryptamine on pulmonary function values in healthy calves
Authors: Desmecht Daniel J-M. , Linden Annick S. , Rollin Frederic A. , Amory Hélène , Lekeux Pierre M.
Published: January 2024

Effects of iv and aerosol administration of 5-hydroxytryptamine (5-ht) on ventilation, pulmonary mechanics values, pulmonary arterial pressure, and heart rate were investigated in healthy unsedated Friesian calves.

Minute volume increased significantly, mainly because of an increase in respiratory rate. Except for total pulmonary resistance after bolus injection, continuous administration of 5-ht given by either route caused significant alterations of lung dynamic compliance and total pulmonary resistance, the former decreasing to one-fifth of its baseline value and the latter increasing twofold. Pulmonary arterial pressure increased significantly, whatever the speed or route of administration. Administration of a bolus did not affect heart rate, whereas continuous iv administration of 5-ht as well by perfusion or by aerosol resulted in sustained tachycardia.

It was concluded that 5-ht induces reversible bronchoconstriction and pulmonary vasoconstriction in healthy unsedated calves, 5-ht-induced functional alterations depend on the speed of administration, and excess of 5-ht production or depression in uptake by the lungs during bovine respiratory tract diseases could contribute to pulmonary dysfunction.
Clinical and metabolic findings in dogs with chronic renal failure fed two diets
Authors: Hansen Bernie , DiBartola Stephen P. , Chew Dennis J. , Brownie Cavell , Nagode Larry
Published: January 2024

Exogenous creatinine clearance, urinary electrolyte excretions, calcium and phosphorus balance, serum cholesterol concentration, arterial blood pressure, and body weight were evaluated in dogs with chronic renal failure that were fed 2 commercial diets. Nine dogs ranging in age from 1 to 15 years were identified as having mild to moderate chronic renal failure (crf, exogenous creatinine clearance = 0.5 to 2.13 ml/kg of body weight/min). These dogs and a group of 10 clinically normal controls were fed a diet containing 31% protein for 8 weeks at which time hematologic and biochemical evaluations and clearance studies were performed. All dogs then were fed a phosphorus-restricted diet containing 16% protein and then reevaluated after 8 weeks.

The dogs in this study had hematologic and biochemical abnormalities typical of crf. Urine absolute and fractional excretion of electrolytes was higher in dogs with crf than in controls and was affected by diet. Serum cholesterol concentration was higher in dogs with crf and increased in those dogs after feeding the low protein diet. Changes in dietary sodium intake did not affect arterial blood pressure. The phosphorus-restricted diet did not affect serum amino terminal parathyroid hormone concentration in either group. Control dogs lost body weight, whereas dogs with crf gained weight when fed the low protein diet.

We concluded that dogs with mild to moderately severe crf have the same biochemical abnormalities and response to dietary restriction of protein and phosphorus as has been previously reported in dogs with experimentally induced crf. Restriction of dietary sodium may not decrease arterial blood pressure in some dogs with crf. Dogs with crf may be predisposed to hypercholesterolemia when fed restricted protein commercial diets, and reduction of dietary phosphorus intake may be inadequate to control renal secondary hyperparathyroidism in dogs with crf.
Effect of probenecid on the pharmacokinetics of flunixin meglumine and phenylbutazone in healthy mares
Authors: Zertuche Juan Manuel L. , Brown Murray P. , Gronwall Ronald , Merritt Kelly
Published: January 2024

Pharmacokinetic values for flunixin meglumine (1 mg/kg of body weight) and phenylbutazone (4 mg/kg) dosages were determined after a single iv injection with and without concurrent intragastric administration of probenecid (50 mg/kg) in 6 healthy mares. Significant difference was not apparent in the pharmacokinetic values of flunixin meglumine with and without concurrent probenecid administration. Significant (P ≤ 0.05) increase was evident in the 12-hour mean concentration of phenylbutazone (11.45 ± 1.66 μg/ml without probenecid; 14.56 ± 1.20 μg/ml with probenecid) along with significant (P ≤ 0.05) reduction in its volume of distribution at steady state associated with concurrent probenecid administration (218.6 ± 11.52 ml/kg without probenecid; 169.4 ± 9.25 ml/kg with probenecid).
Factors affecting skim milk progesterone assay results
Authors: Nachreiner R. F. , Oschmann S. J. , Edqvist L. -E. , Richards J. I.
Published: January 2024

Five studies were performed to determine factors affecting progesterone concentration in skim milk. Results of the first study indicated that progesterone concentration was higher in skim milk of samples kept 16 hours in an ice bath (0 C) than of those left at room temperature (21 C). In the second study, this temperature effect was found to be reversible, with skim milk progesterone concentration increasing when whole milk samples were cooled prior to centrifugation. In the third study, [3H]-labeled progesterone was used to determine the relationship between fat content of foremilk (the first milk obtained from the teats), midmilk (milk obtained midway through milking), and strippings (milk obtained immediately after milking machines have been removed) samples and temperature (4 C and 21 C) on the percentage of progesterone in the skim milk fraction. The relationship between percentage of butterfat and percentage of progesterone in skim milk was linear when the log of these variables was used for calculations. In the fourth study, assayable progesterone in the skim milk fraction of foremilk, midmilk, and strippings was affected by temperature. In the fifth study, a multiple-regression procedure was used to determine the amount of variation in percentage of radioactive progesterone in the skim milk - fraction. Independent variables (whole milk butterfat and temperature of incubation [1, 3, 13, 22, 37, and 50 C]) and the natural log of each variable, were entered into a step-wise multiple-regression analysis. The log of the temperature and percentage of butterfat of whole milk at the time of centrifugation accounted for 89.2% (r2 = 0.892) of the variation in the log of the progesterone concentration in the skim milk fractions. The equation describing this relationship was: log percentage of progesterone in the skim milk fraction = 4.046 — 0.144 × (log of temperature of whole milk sample) × 0.688 × (log percentage of butterfat in whole milk sample). The loss of progesterone from skim milk fractions of warm whole milk samples is possibly a physical phenomenon dependent on the temperature of the sample and its percentage of butterfat. A nomograph was created to allow others to use these variables in making adjustments in progesterone concentrations.
Antigenic variation of Mycoplasma gallisepticum, as detected by use of monoclonal antibodies
Authors: Panangala Victor S. , Morsy Mohamad A. , Gresham Martha M. , Toivio-Kinnucan Maria
Published: January 2024

A panel of monoclonal antibodies (MAb) developed against Mycoplasma gallisepticum strain PG31 was used to probe the antigenic profiles of 5 recognized strains (PG31, R, S6, F, A5969) and 6 field isolates of M gallisepticum. Monoclonal antibody G9 predominantly recognized antigens at apparent molecular mass positions of 90 to 98 kDA. The MAb reacted with all strains and isolates, but the molecular mass position of the antigens varied among some mycoplasmas. Monoclonal antibody G12 reacted with all strains and isolates of M gallisepticum and had an identical banding pattern. However, MAb G10 and G11 reacted selectively only with a limited number of strains and/or isolates. Surface distribution of the MAb-recognized antigens was revealed by immunoelectron microscopy.

Partial physicochemical characterization of MAb G9-recognized antigens identified glycopeptide characteristics. Monoclonal antibody G9 reacted with surface antigens and, hence, participated in agglutination of M gallisepticum. However, the degree of agglutination varied among the various strains and isolates, indicating a quantitative or conformational limitation or an alteration in the anomeric expression of the epitopes. Antigenic variation in M gallisepticum may be mediated by immunologic selective pressures, or a proclivity for habit niche in the host.
Use of infected cultured cells to compare ultrastructural features of Neospora caninum from dogs and Toxoplasma gondii
Authors: Lindsay D. S. , Speer C. A. , Toivio-Kinnucan M. A. , Dubey J. P. , Blagburn B. L.
Published: January 2024

The ultrastructure of tachyzoites of 3 isolates of Neospora caninum from dogs was examined, using transmission electron microscopy of infected cultured cells. Ultrastructure of the 3 isolates was similar. Tachyzoites had a pellicle, 22 subpellicular microtubules, a conoid, anterior and posterior polar rings, 8 to 12 electron-dense rhoptries, numerous micronemes, a single vesicular nucleus, tubular mitochondria, Golgi complexes, ribosomes, endoplasmic reticula, an inactive micropore, electron-dense bodies, lipid bodies, and amylopectin bodies. Most tachyzoites were located adjacent to the host cell nucleus in a parasitophorous vacuole that contained numerous intravacuolar tubules. Tachyzoites divided by endodyogeny. Neospora caninum tissue cysts were not seen. Comparison of N caninum with Toxoplasma gondii tachyzoites indicated that the 2 species can be differentiated on the basis of structure and numbers of rhoptries and numbers and location of micronemes and electron-dense bodies.
Effects of oral administration of anti-inflammatory doses of prednisone on thyroid hormone response to thyrotropin-releasing hormone and thyrotropin in clinically normal dogs
Authors: Moore George E. , Ferguson Duncan C. , Hoenig Margarethe
Published: January 2024

Prednisone was given orally to 12 dogs daily for 35 days at an anti-inflammatory dosage (1.1 mg/kg of body weight in divided dose, q 12 h) to study its effect on thyroxine (T4) and triiodothyronine (T3) metabolism. Six of these dogs were surgically thyroidectomized (THX-Pred) and maintained in euthyroid status by daily SC injections of T4 to study peripheral metabolism while receiving prednisone; 6 dogs with intact thyroid gland (Pred) were given prednisone; and 6 additional dogs were given gelatin capsule vehicle as a control group (Ctrl).

Baseline T4 concentration after 4 weeks of treatment was not significantly different in dogs of the THX-Pred or Pred group (mean ± SEM, 2.58 ± 0.28 or 3.38 ± 0.58 μg/dl, respectively) vs dogs of the Ctrl group (2.12 ± 0.30 μg/dl). A supranormal response of T4 to thyrotropin was observed in dogs of the Pred group, but the T4 response to thyrotropinreleasing hormone was normal. Baseline T3 concentration in dogs of both steroid-treated groups was significantly (P< 0.05) lower after 2 and 4 weeks of prednisone administration vs pretreatment values, but normalized 2 weeks after prednisone was stopped. Free T3 (FT3) and T4 (FT4) fractions and absolute FT3 and FT4 concentrations were not altered by prednisone administration. Reverse T3 (rT3) concentration in vehicle-treated Ctrl dogs (26.6 ± 3.5 ng/dl) was not different from rT3 concentration in dogs of the THX-Pred (25.7 ± 4.3 ng/dl) and Pred (28.9 ± 3.8 ng/dl) groups after 4 weeks of medication. These data indicate that daily oral administration of such anti-inflammatory dose of prednisone for 1 month reduces baseline serum T3 concentration, does not alter serum T4 concentration, and enhances thyroidal sensitivity to thyrotropin.
Peripartum acute-phase protein serum amyloid-A concentration in plasma or cows and fetuses
Authors: Alsemgeest S. Peter M. , Taverne Marcel A. M. , Boosman Roel , van der Weyden Bert C. , Gruys Erik
Published: January 2024

Concentration of the acute-phase protein serum amyloid-A (saa) was measured by means of an indirect ELISA method, in plasma of 3 pregnant cows and in plasma taken by cannula from another 4 pregnant cows and, by separate cannula, from their fetuses. Blood samples were taken daily from approximately 72 hours before until 72 hours after parturition. After parturition, saa concentration increased significantly (P < 0.05) in maternal plasma. In fetal plasma, only a nonsignificant increase was found at time of delivery. The concentration of maternal saa started to increase within the first 24 hours after delivery, reaching a peak value between 24 and 48 hours after delivery.

In the aforementioned plasma samples from the 4 pregnant cows and their fetuses, the concentration of maternally derived cortisol increased nonsignificantly after parturition. The concentration of fetally derived cortisol was significantly (P< 0.05) increased at parturition (t = 0), compared with the initial fetal cortisol concentration at 120 hours before delivery.

Peripartum concentration of maternal saa increased and maternal cortisol remained low, whereas fetal saa concentration remained low and fetal cortisol concentration increased. These findings indicate possible suppressive action of fetal cortisol on fetal saa production. However, it might be argued that the main cause of the difference in saa concentration is the difference in tissue damage between cows and fetuses at parturition.
Refractive state of aphakic and pseudophakic eyes of dogs
Authors: Davidson M. G. , Murphy C. J. , Nasisse M. P. , Hellkamp A. S. , Olivero D. K. , Brinkmann M. C. , Campbell L. H.
Published: January 2024

Streak retinoscopy was performed by 5 ophthalmologists on 256 eyes (191 dogs) to determine their postoperative refractive state after cataract extraction. Aphakic and pseudophakic eyes that had been implanted with 1 of 5 intraocular lenses (iol) with dioptric powers ranging from + 14.5 to + 38 diopters (D) were studied. By use of ANOVA, breed and body type of dog and individual performing refraction were found to have no detectable effect on final refractive state. Mean refractive state of aphakic eyes was +14.4 ± 2.10 D. Mean refractive state for different iol powers was as follows: + 14.5 D iol = + 11.54 ± 1.18 D (n = 13); +30 D iol = + 5.15 ± 1.18 D (n = 105); + 34.0 D iol = +3.5 D (n = 1); +36 D iol = +2.34 ± 0.73 D 9 (n = 61); and +38 D iol = + 1.41 ± 0.56 D (n = 28). Residual hyperopia ranged from +0.5 D to +2.5 D with +38 D iol, and no eyes were myopic (overcorrected) by use of any of the iol studied. Linear regression analysis of refractive state on iol power for all dogs predicted that dioptric strength of +41.53 D was necessary to best approximate emmetropia for the population as a whole. Body type of the dog had only slight effect (< 1.0 D) on predicted optimal iol power. Further linear regression analysis of the 7 breeds studied predicted variations from +39.62 to +43.14 D in iol powers necessary to approximate emmetropia. Results of the study support the routine use of canine iol with dioptric strength of approximately + 41.5 D in circumstances in which preoperative biometry and keratometry are not practical. The findings further suggest that, for the specific population of dogs studied, most of the dogs could be corrected to near emmetropia by use of a small range of iol dioptric strengths, irrespective of body type or breed.
Qualitative and morphometric radiographic findings in the distal phalanx and digital soft tissues of sound Thoroughbred racehorses
Authors: Linford Robert L. , O'Brien Timothy R. , Trout Donald R.
Published: January 2024

Lameness examinations and radiography of the distal phalanx and associated soft-tissue structures of the front feet of 103 Thoroughbred racehorses, 4 to 9 years old, were performed to determine normal radiographic appearance and morphometry. Of 103 horses examined, 41 were used in the study that were without clinical signs of foot problems or lameness, had raced at least twice prior to radiography, and had raced at least twice more in the 6 months after radiography.

Lateromedial and dorsoproximal-palmarodistal radiographic views of each front distal phalanx were used to measure 28 bone and soft-tissue structures, and to evaluate 14 radiographic findings. Significant differences were not observed between left and right digits for any radiographic determination.

Mean thickness of the soft tissues dorsal to the distal phalanx, which provides an evaluation of the epidermal laminae, was 14.6 ± 1.0 mm when measured adjacent to the distal aspect of the distal phalanx. Most horses had straight, smooth hoof walls that were parallel to the dorsal cortex of the distal phalanx. The mean degree of palmar rotation of the distal phalanx was −0.5 ± 1.3, and none was rotated more than 4°.

The dorsal cortex was smooth and straight, without bone deposition or reaction in either digit for only 5 of the 41 horses. Active bone formation was seen unilaterally along the middle portion of the dorsal cortex in 7 horses, and along the distal portion of the dorsal cortex in 4 of the phalanges from 3 horses. New bone formation along the distal dorsal cortex was often accompanied by resorption of the palmar cortex. For 26 of the 31 horses without active bone deposition, smooth inactive bone formation along the midportion of the dorsal cortex was identified in 1 or both distal phalanges.

Bone at the solar margin of the distal phalanx was uniformly dense and finely trabeculated, without evidence of resorption or fractures. Severe irregularity of the solar margin was not found in any digit, and the margin of both phalanges was smooth in 8 horses. Various degrees of solar margin irregularity were observed in the other 33 horses.

The mean number of vascular canals within the distal phalanx was 8.4 ± 1.7, and the diameter of the largest canal was 3.4 ± 0.6 mm. A mean number of 2.0 ± 1.2 vascular canals was oriented parallel to the radiographic beam on the dorsoproximal-palmarodistal view, and these were termed end-on vessels, because they were visualized as radiolucent dots ≥ 1 mm in diameter in the central portion of the distal phalanx.

Racing performance of horses with subtle radiographic signs of laminitis (palmar rotation, hoof wall curvature or undulations, palmar cortical resorption, distal dorsal cortical bone deposition) was poorer than that of horses without these signs. These findings are suggestive of a subclinical laminitis condition, which may influence performance without causing overt clinical signs.
Biomechanical study of the effect of coxofemoral positioning on passive hip joint laxity in dogs
Authors: Heyman Steven J. , Smith Gail K. , Cofone Mark A.
Published: January 2024

Ten coxofcmoral joints from 5 dog cadavers were used to study the effect of coxofcmoral positioning on passive hip laxity. A material test system was used to measure lateral translation when force was between 20 N of compression and 40 N of distraction. Using the orthogonal coordinate system imposed in this study, neutral position was empirically defined at 15° of extension and 10° of abduction, relative to the plane of the pelvis, and no internal or external rotation of the femur. The hips were mounted in a custom-designed jig that allowed 1 rotational degree of freedom (ie, either flexion extension, adduction/ abduction, or internal/external rotation), while holding the other 2 constant. Lateral translation of the hips was tested at 10° intervals from 30° of flexion to 70° of extension, 40° of adduction to 60° of abduction, and 30° of internal rotation to 40° of external rotation. Lateral displacement was maximal at 10° of extension, 20° of abduction, and 10° of external rotation, approximating the neutral coxofcmoral position during stance. As the hips were rotated into extreme positions, the amount of lateral displacement occurring with the same applied load decreased significantly to 32.0 to 65.3% of the maximal displacement. Determining the position of the hip associated with maximal passive laxity in vitro is essential to the design of a precise and accurate clinical stress-radiographic method to quantitate joint laxity in dogs. Our results confirm earlier work that passive hip joint laxity is at a maximum with the hip approximately in a neutral weight-bearing position.
Dose-response relation between plasma concentrations of corticotropin and Cortisol after administration of incremental doses of cosyntropin for corticotropin stimulation testing in cats
Authors: Peterson Mark E. , Kemppainen Robert J.
Published: January 2024

We compared the plasma Cortisol and immunoreactive corticotropin (IR-ACTH) responses to incremental doses (1.25, 12.5 and 125 μg) of synthetic ACTH (cosyntropin) administered IV to 6 clinically normal cats. Mean plasma Cortisol concentration increased significantly (P < 0-0001) after administration of all 3 doses of cosyntropin. After administration of the 1.25- and 12.5-μg doses, plasma Cortisol concentration peaked at 30 minutes, then decreased to values not significantly different from baseline concentration by 90 and 120 minutes, respectively. In contrast, after administration of the 125-μg dose, mean Cortisol concentration peaked at 60 minutes and remained significantly (P < 0.05) higher than baseline values at 120 minutes. Compared with the 1.25- and 12.5-μg doses, administration of the 125-μg dose of cosyntropin induced significantly (P < 0.05) higher Cortisol responses at 60, 90, and 120 minutes. Although individual cat's peak plasma Cortisol concentration after administration of the 125-μg dose was higher than the peak value determined after administration of the 2 lower doses of cosyntropin, these differences were not statistically significant. Mean plasma IR-ACTH concentration increased significantly (P < 0.0001) and reached a maximal value at 30 minutes after administration of all 3 doses of cosyntropin. After administration of the 1.25- and 12.5-μg doses, plasma IR-ACTH concentration decreased to values not significantly different from baseline concentration by 60 and 120 minutes, respectively, whereas mean IR-ACTH concentration remained significantly (P < 0.05) higher than baseline values 120 minutes after administration of the 125-μg dose. Mean peak plasma IR-ACTH concentration attained after administration of the 125-μg dose of cosyntropin was significantly higher than that attained after administration of the 2 lower doses. Peak plasma IR-ACTH concentration attained after administration of the 12.5-μg dose of cosyntropin was significantly higher than that attained after administration of 1.25 μg of cosyntropin. Results of the study indicate that IV administration of cosyntropin at doses ranging from 1.25 to 125 μg induces similar peak plasma cortisol responses in clinically normal cats, indicating that all of the doses may maximally stimulate the adrenal cortex. Administration of the higher cosyntropin doses did, however, result in more prolonged adrenocortical response.
Changes in fluid composition on the serosal surface of jejunum and small colon subjected to venous strangulation obstruction in ponies
Authors: Ruggles Alan J. , Freeman David E. , Acland Helen M. , Simmons Marie Fitz
Published: January 2024

In 6 anesthetized ponies, 3 segments of jejunum and 3 segments of small colon were isolated from the peritoneal cavity in plastic bags filled with Hanks' balanced salt solution. One jejunal and 1 small colon segment were subjected to venous strangulation obstruction for 3 hours (vso-3), venous strangulation obstruction for 6 hours (vso-6), or a 6-hour sham procedure to control for changes induced by isolation in a plastic bag. Additional segments of jejunum and colon that were not placed in bags served as controls for histologic examination and collagenase measurements. Samples of fluid surrounding the intestine were obtained for chemical analyses, nucleated cell count, aerobic and anaerobic bacteriologic culture, and measurement of collagenase activity. Full-thickness tissue samples were obtained for histologic examination and measurement of collagenase content.

Bacteria did not cross the intestinal wall after 3 and 6 hours of vso, despite severe mucosal lesions in these segments. At 6 hours, Po2 was significantly less and Pco2 was significantly (P<0.05) greater in the fluid surrounding the vso-6 jejunal segments, compared with the sham jejunal segments. The pH was significantly (P<0.05) less in fluid surrounding vso-6 small colon segments, compared with the sham colon segments at 6 hours. For jejunum and small colon, phosphate and lactate concentrations were significantly (P<0.05) greater in vso-6 fluid than in the corresponding sham fluids at 6 hours. Fibrin formed around all vso segments, although fibrinogen was not detected in the surrounding fluid, indicating possible rapid conversion of fibrinogen to fibrin. Fluid collagenase activity increased significantly (P<0.05) in all segments over 6 hours. The preparation used in this study was successful in measuring local changes on the serosal surface of intestine subjected to vso and in isolating segments under study in a sterile environment.
Vertical ground reaction force distribution during experimentally induced acute synovitis in dogs
Authors: Rumph Paul F. , Kincaid Steven A. , Baird Debra K. , Kammermann John R. , Visco Denise M. , Goetze Leopold F.
Published: January 2024

The pattern of vertical ground reaction force redistribution among limbs during episodes of acute synovitis of the stifle in 12 mixed-breed dogs was investigated as an adjunct to a blinded nonsteroidal anti-inflammatory drug efficacy study. Without regard to drug efficacy groupings, the redistribution of vertical forces before and during the acute synovitis episode was evaluated by analysis of gait, using a force platform.

Acute synovitis was induced by intrasynovial injection of sodium urate crystals. Simultaneously, each dog was given 1 of 4 treatment regimens, including iv injection of sterile saline solution (as a negative control), phenylbutazone (as a positive control), or 1 of 2 proprietary nonsteroidal anti-inflammatory drugs. Postinjection analyses took place at 2, 4, 8, 12, 24, and 36 hours. The peak vertical force redistribution in the 3 untreated limbs of the dogs was described.

The greatest redistribution was observed 4 hours after substance injection when the synovitis was clinically at maximum. Thereafter, there was steady improvement and the dogs had a clinically normal gait 24 hours after substance injection. During synovitis, peak vertical force increased in the contralateral hind limb. During the more severe synovitis episodes, force was decreased in both forelimbs. There was good correlation between severity of lameness and peak vertical force response in the contralateral hind limb. Results of the study indicate that the untreated limbs of the same animal should not be used as a control during acute lameness studies.
Evaluation of the caudoventral portion of the mandible as a donor site for corticocancellous bone for periodontal surgery in dogs
Authors: Smith Mark M. , Saunders Geoffrey K. , Moon Martha L. , Payne John T.
Published: January 2024

Corticocancellous bone graft was obtained from the caudoventral portion of the mandible of 8 dogs. The recipient site was an alveolar jugal and alveolar defect from vital root amputation of the mesiobuccal root of the maxillary fourth premolar. Anatomic observations of 20 canine cadavers indicated that guidelines for harvesting bone from the caudoventral portion of the mandible of dogs were the mesial aspect of the masseteric fossa, the distal aspect of the roots of the first mandibular molar, and the ventral aspect of the mandibular canal. The mean weight of corticocancellous bone harvested was 0.4 ± 0.1 g. Harvested corticocancellous bone was adequate to fill recipient sites measuring a mean volume of 105.0 ± 28.5 mm3. Histologic evaluation of the recipient site revealed progressive osseous integration of the bone-graft site during a mean follow-up period of 3.5 ± 1.9 months. There was normal bone healing of the donor site without adverse effects on the mandibular molars or neurovascular structures of the mandibular canal. Vital amputation sites receiving silver amalgam had evidence of plasmacytic/lymphocytic inflammation associated with residual silver amalgam in the bone-graft area. The caudoventral portion of the mandible may be used as a donor site for autogenous corticocancellous bone in periodontal surgery of dogs.
Accuracy of a reflectance pulse oximeter in anesthetized horses
Authors: Watney G. C. G. , Norman Wendy M. , Schumacher J. P. , Beck E.
Published: January 2024

The accuracy of a reflectance pulse oximeter was determined in 22 anesthetized horses. Oximetric blood oxygen saturation was measured with the pulse oximeter probe attached to the mucosa of the mandible. Arterial blood oxygen saturation (Sao2) was calculated from arterial blood gas values and the equine blood oxygen dissociation curve. The mean ± SD difference between oximetric blood oxygen saturation and Sao2 was −1.3 ± 3.1% for values of Sao2 ranging from 80 to 100%. The difference between oximetric blood oxygen saturation and Sao2 was influenced by Sao2, the mean arterial blood pressure, and preanesthetic medication administered, but not by age, sex, or body weight of the horse, individual animal effect, anesthetic induction or maintenance agent, procedure performed, body position, mode of lung ventilation, time of sampling, arterial pH, or carbon dioxide tension.
Effects of dietary electrolyte balance on subluxation of the femoral head in growing dogs
Authors: Kealy R. D. , Lawler D. F. , Monti K. L. , Biery D. , Helms R. W. , Lust G. , Olsson S.-E. , Smith G. K.
Published: January 2024

Effects of increased dietary chloride and reduced sodium and potassium ion concentrations on coxofemoral joint conformation, as assessed by radiography, were examined in growing dogs. Dietary electrolyte balance was quantified by dietary anion gap (dag), defined as Na+ + K+ - Cl- in milliequivalents per 100 g of food. Diets had anion gap ranging from 8 to 41 mEq/100 g of food. One hundred sixty-seven pups from 27 litters representing 5 breeds were studied during the period of rapid growth. The extent of subluxation of the femoral head was measured on radiographs, using the method of Norberg. On average, less subluxation of the femoral head (P < 0.05) was observed when diets with lower dag were fed. Differences in dag balance did not result in different rates of weight gain; therefore, the reduction in coxofemoral joint subluxation attributable to low dag was unrelated to weight gain. Norberg angles measured at 30 weeks of age were highly correlated with coxofemoral joint status at 2 years of age, as measured by the Swedish diagnostic system and the scoring system of the Orthopedic Foundation for Animals (|r| ≥ 0.70, P < 0.0002, n = 24). This diet-related improvement in coxofemoral joint subluxation would be expected, on average, to delay or mitigate the characteristic clinical and radiographic signs of hip dysplasia in growing dogs.
Pharmacokinetics and concentrations of ceftiofur sodium in body fluids and endometrium after repeated intramuscular injections in mares
Authors: Cervantes Carlos C. , Brown Murray P. , Gronwall Ronald , Merritt Kelly
Published: January 2024

Each of 5 healthy mares was given 5 consecutive im injections of ceftiofur sodium (2 mg/kg of body weight; 50 mg/ml) at 12-hour intervals. Ceftiofur concentrations were measured serially in serum, synovial fluid, peritoneal fluid, and urine, and were measured in CSF and endometrial tissue after the fifth dose. Mean elimination rate constant was 0.354 ± 0.101 h−1 and elimination half-life was 2.49 ± 0.49 hour. Mean serum ceftiofur concentrations peaked approximately 1 hour after each injection. The highest mean ceftiofur concentration was 5.09 μg/ml at 1 hour after the fifth dose for serum, 3.02 μg/ml at 2 hours after the fifth dose for synovial fluid, and 3.23 μg/ml at 4 hours after the fifth dose for peritoneal fluid. Mean urine concentrations reached 15.72 μg/ml at 1 hour after the fifth dose. Ceftiofur was not detected in csf or endometrial tissue. None of the mares had adverse reactions to the drug.
Dexamethasone pharmacokinetics in clinically normal dogs during low- and high-dose dexamethasone suppression testing
Authors: Greco Deborah S. , Brown Scott Anthony , Gauze Johna J. , Weise Dale W. , Buck Joan M.
Published: January 2024

Dexamethasone pharmacokinetics was studied in 10 healthy dogs receiving high-dose administration of dexamethasone (dosage, 0.1 mg/kg of body weight, iv), alone or combined with acth (dosage, 0.5 U/kg, iv), or low-dose administration of dexamethasone (dosage, 0.01 mg/kg, iv) in an incomplete cross-over design. Serum samples were obtained at 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, 720, 1,080, 1,440, 1,920, 2,400, and 2,880 minutes after dexamethasone administration; dexamethasone was measured by radioimmunoassay validated for use in dogs. Dexamethasone pharmacokinetics was adequately described by a two-compartment first-order open model.

Comparison of pharmacokinetics for the low- and high-dose protocols revealed dose dependence; area under the curve, mean residence time, clearance, and volume of distribution increased significantly when dexamethasone dosage increased. The elimination rate constant was significantly (P < 0.05) less, and the elimination half-life significantly greater for the high-dose protocols; however, the distribution rate constant and distribution half-life were not significantly different when high-dose protocols were compared with the low-dose protocol. Dose-dependent increases in volume of distribution and clearance may be related to saturation of protein-binding sites. Concurrent administration of acth did not affect dexamethasone disposition.
Histomorphologic features of the nasal cavity of pigs exposed to Pasteurella multocida type-D dermonecrotic toxin
Authors: Ghoshal Nani G. , Niyo Yosiya
Published: January 2024

Microscopic examination of the nasal mucosa of clinically normal specific-pathogen-free pigs and of toxicogenic type-D Pasteurella multocida toxin challenge-exposed_ specific-pathogen-free pigs indicated that the surface epithelium in pigs of both groups was microscopically normal; erosions or appreciable inflammatory changes were not evident. In pigs of both groups and in all 3 regions of the nasal cavity, the endothelial lining of all blood vessels appeared normal without detectable changes to the walls at postinoculation day 10. Vascular injury in the cartilage or the bone was not discernible in control or challenge-exposed pigs.

There were marked differences in the osseous structures of the conchae when the 2 groups were compared. In control pigs, active bone formation and remodeling were observed, and the septal cartilage was normal. In toxin challenge-exposed pigs, there likewise was normal bone formation and remodeling in the vestibular region, and the septal cartilage was normal. In marked contrast, conspicuous changes were observed in the osseous core of the conchae of the respiratory and, sometimes, the olfactory regions. These changes consisted of bone necrosis and resorption by large numbers of osteoclasts with variable replacement by dense mesenchymal stroma, which resulted in conchal atrophy. In the absence of any discernible damage or injury (angiopathy) to the nasal vessels, it appears that the action of the dermonecrotoxin of P multocida serotype D is on the most active osteoblasts and the associated organic matrix of the bone, with subsequent disruption of normal bone formation and remodeling of the nasal conchae.
Ultrastructural features and pathogenesis of knobbed spermatozoa in a boar
Authors: Toyama Yoshiro , Itoh Yoneto
Published: January 2024

Ultrastructures of knobbed spermatozoa in a boar were observed. The knobs, found at the apex of the spermatozoa, were spherical swellings of the acrosome; vacuoles were found in the swellings. According to the contents, 2 types of the vacuoles were recognized: a vacuole containing cell debris that was surrounded by 2 or 3 layers of membranes, and a vacuole containing an amorphous material that was surrounded by a single membrane. Several vacuoles might be observed in a knob. Observations of both testes indicated that the cell debris in the vacuole of the knob was derived from the cytoplasm of the Sertoli cell, which evaginated into the spermatid. Origin of the amorphous material in the other type of knob is not known.
Use of flow-volume loops to evaluate upper airway obstruction in exercising Standardbreds
Authors: Lumsden Jonathan M. , Derksen Frederik J. , Stick John A. , Robinson N. Edward
Published: January 2024

Flow-volume loops generated from 6 Standardbreds at rest and during treadmill exercise were evaluated for their use in detecting upper airway obstruction. Tidal breathing flow-volume loops (tbfvl) were obtained from horses at rest and exercising at speeds corresponding to 75% of maximal heart rate and at maximal heart rate. The tbfvl were evaluated, using a pulmonary function computer; calculated indices describing airflow rate and expiratory-to-inspiratory airflow ratio for individual loops were determined. In addition to tbfvl indices, standard variables of upper airway function also were measured: peak airflow, peak pressure, and calculated inspiratory and expiratory impedances. Measurements were recorded before left recurrent laryngeal neurectomy (lrln; baseline) and 14 days after surgically induced left laryngeal hemiplegia.

When horses were at rest, tbfvl shape and indices describing the loop were highly variable. In contrast, in exercising horses, tbfvl shape was consistent and coefficients of variation of loop indices were less during exercise than at rest. After lrln, tbfvl from exercising horses indicated marked inspiratory airflow limitation, while the expiratory airflow curve was preserved. Peak inspiratory flow rate and inspiratory flow at 50 and 25% of tidal volume decreased, and the ratio of peak expiratory to inspiratory airflow and that of midtidal volume expiratory and inspiratory airflow rates increased significantly (P < 0.05). Inspiratory impedance also increased after lrln.

Although in resting horses tbfvl were not a useful indicator of upper airway obstruction, examination of tbfvl from exercising horses allowed objective, specific, and repeatable detection of upper airway obstruction. The technique was noninvasive, rapid, and well tolerated by horses; thus, it is a potentially valuable clinical diagnostic test.
Furosemide attenuates the exercise-induced increase in pulmonary artery wedge pressure in horses
Authors: Manobar Murli
Published: January 2024

Right atrial (ra), right ventricular (rv), pulmonary artery (pa), and pulmonary artery wedge (paw) pressures were examined, using catheter-mounted micromanometers, in 8 healthy horses at rest and during galloping on a treadmill at belt speeds of 8, 10, and 13 m/s. The in vivo signals from the micromanometers were matched with those from conventional fluid-filled catheter transducers leveled at the scapulohumeral joint. Thirty minutes after completing control exercise measurements, furosemide was administered iv at a dosage of 1 mg/kg of body weight, and resting, as well as exercise, measurements were repeated 4 hours later. Studies also were performed on a separate day, when only postfurosemide resting and exercise data were collected. Prefurosemide and postfurosemide heart rate values for rest (37 ± 2 beats/min, mean ± sem), as well as for exercise (213 ± 5 beats/min at 13 m/s), were similar. Prefurosemide mean ra, pa, and paw pressures were increased significantly (P < 0.05) from resting values of 8 ± 2, 31 ± 2, and 18 ± 2 mm of Hg, respectively, to 44 ± 4,89 ± 5, and 56 ± 4mm of Hg with exercise at 13 m/s. Furosemide administration resulted in marked diuresis, and resting mean ra, pa, and paw pressures decreased significantly (P < 0.05) to 1 ± 1, 27 ± 2, and 11 ± 2 mm of Hg, respectively, 4 hours after furosemide administration. Although pressures increased markedly with exercise (corresponding values being 31 ± 5, 79 ± 6, and 44 ± 4 mm of Hg), these 4-hour postfurosemide exercise values were significantly (P < 0.05) less than those recorded with prefurosemide exertion. Intravascular pulmonary capillary pressure, calculated as the average of mean pa and paw pressures, during prefurosemide exercise (73 ± 5 mm of Hg) significantly (P < 0.05) exceeded that during exercise performed 4 hours after furosemide administration (61 ± 5mm of Hg). Attenuation by furosemide of the exercise-induced increase in pulmonary capillary pressure may have a role in limiting or reducing the extent of exercise-induced pulmonary hemorrhage in horses.