bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences between longitudinal and circular smooth muscle in β-adrenergic control of motility of isolated equine ileum
Authors: Belloli Chiara , Re Giovanni , Arioli Francesco , Badino Paola , Carcano Roberta , Odore Rosangela , Girardi Carlo , Beretta Carlo 
Published: January 2024

SUMMARY

Objective
To identify β-adrenoceptor subtypes involved in motility inhibition of circular and longitudinal smooth muscle layers of equine ileum.

Sample Population
Isolated strips of equine ileum circular smooth muscle and membrane preparations from circular and longitudinal muscle layers.

Procedure
Functional assays of circular muscle preparations and radioligand binding assays and measurements of cAMP production in smooth muscle membranes from circular and longitudinal layers.

Results
Selective β-adrenergic agonists exerted inhibitory effects on circular muscle preparations. Binding studies of cell membranes indicated that the density and distribution of 3 β-adrenoceptor subtypes did not differ between longitudinal and circular muscle layers. Measurement of cAMP production in membrane preparations of longitudinal and circular muscle after selective β-stimulation confirmed presence of the 3 adenylate cyclase-coupled β-adrenoceptor subtypes; however, preparations from the 2 layers had differing cAMP production efficacy.

Conclusions
The data may partly explain the differing functional responses between circular and longitudinal muscle preparations.

Clinical Relevance
Findings support the important role of β-atypical adrenoceptors in the inhibitory regulation of equine ileum motility. (Am J Vet Res 1997;58:1422–1426)
Pharmacokinetics of cisapride in horses after intravenous and rectal administration
Authors: Cook Gabriel , Papich Mark G. , Roberts Malcolm C. , Bowman Karl F. 
Published: January 2024

SUMMARY

Objectives
To determine the IV pharmacokinetics of cisapride and measure systemic absorption after rectal administration.

Animals
5 healthy adult mares (380 to 610 kg).

Procedure
Cisapride was administered, IV, at a dosage of 0.1 mg/kg of body weight. In the same horses, after a 1-week washout period, cisapride was administered rectally at a dosage of 1 mg/kg by mixing crushed tablets with propylene glycol and administering the mixture into the rectum. After each drug administration, a series of blood samples were collected. Plasma was obtained and analyzed by high-performance liquid chromatography to determine cisapride concentration profiles after each drug administration.

Results
After IV administration, peak plasma concentration was 221.4 ng/ml and harmonic mean half-life was 1.9 hours. Rectal absorption of cisapride was negligible. Cisapride was detected in plasma from only 3 of 5 horses for which mean systemic availability was 1.23%. Mean maximal plasma concentration after rectal administration of cisapride was 13.5 ng/ml.

Conclusion and Clinical Relevance
After IV administration of cisapride, plasma concentration is high for approximately 2 hours. Cisapride mixed with propylene glycol and administered rectally at a dosage of 1 mg/kg is poorly and incompletely absorbed. Thus, cisapride is not clinically useful for rectal administration in horses. (Am J Vet Res 1997;58:1427–1430)
Insulin-like growth factor I peptide elution profiles from fibrin polymers determined by use of high-performance liquid chromatography
Authors: Foley Robert L. , Nixon Alan J. 
Published: January 2024

SUMMARY

Objective
To develop a high-performance liquid chromatography (HPLC) assay for insulin-like growth factor I (IGF-I) and to use it to quantify elution of IGF-I from polymerized fibrin in an in vitro system.

Sample Population
Equine fibrinogen and calcium-activated bovine thrombin were used to form fibrin containing human recombinant IGF-I.

Procedure
Multiple fibrin disks were formed from polymerized fibrinogen and thrombin; 6 disks were loaded with 25 μg of recombinant human IGF-I at the time of polymerization, and 4 remained as unladen controls. The resultant clots were incubated at 37 C and 90% humidity for 22 days. Phosphate-buffered saline solution in each well was replaced daily, and IGF-I content was assayed by HPLC. Solid-phase separation was used to assay free IGF-I peptide peaks. A scan was done to determine optimal wavelength for IGF-I absorbance. Commercially pure IGF-I was used to construct a standard curve, and the IGF-I content of medium removed from all 10 wells each day was assayed.

Results
Pure unbound IGF-I eluted from the fibrin polymers for 22 days; initial rapid daily release of 1.6 to 1.7 μg of IGF/ml of medium changed after day 3 to commence an asymptotic decrease to 110 ng of IGF/ml by day 22. The fibrin disks had dissolved by day 22, and the experiment was terminated. Control disks did not have detectable IGF-I content at any time. Limit of the HPLC assay was 25 ng of IGF-l/ml. Retention time for nonprotein-bound IGF-I was 10.3 ± 0.15 minutes.

Conclusion
IGF-I (25 μg) can be added to polymerized fibrin and eluted as free ligand over a 22-day period of culture at 37 C. Release of IGF-I was initially independent of fibrin dissolution, but later appeared to follow a pattern consistent with fibrin degradation.

Clinical Relevance
IGF-I can be incorporated as a depot form in polymerized fibrin and is released over time in sufficient concentration to effectively stimulate articular chondrocyte metabolic activity. (Am J Vet Res 1997;58:1431–1435)
Comparison of alveolar ventilation, oxygenation, pressure support, and respiratory system resistance in response to noninvasive versus conventional mechanical ventilation in foals
Authors: Hoffman Andrew M. , Kupcinskas Rachel L. , Paradis Mary Rose 
Published: January 2024

SUMMARY

Objective
To compare the efficacy of positive pressure ventilation applied through a mask versus an endotracheal tube, using anesthetized/paralyzed foals as a model for foals with hypoventilation.

Animals
Six 1-month-old foals.

Procedure
A crossover design was used to compare the physiologic response of foals to 2 ventilatory techniques, noninvasive mask mechanical ventilation (NIMV) versus endotracheal mechanical ventilation (ETMV), during a single period of anesthesia and paralysis. Arterial pH, Pao2, Paco2, oxygen saturation, end-tidal CO2 tension, airway pressures, total respiratory system resistance, resistance across the upper airways (proximal to the midtracheal region), and pos-itive end-expiratory pressures (PEEP) were measured. Only tidal volume (VT; 10, 12.5, and 15 ml/kg of body weight) or PEEP (7 cm of H2O) varied.

Results
Compared with ETMV, use of NIMV at equivalent VT resulted in Paco2 and pH values that were significantly higher, but Pao2 was only slightly lower. Between the 2 methods, peak airway pressure was similar, but peak expiratory flow was significantly lower and total respiratory resistance higher at each VT for NIMV. Delivery of PEEP (7 cm of H2O) was slightly better for ETMV (7.1 ± 1.3 cm of H2O) than for NIMV (5.6 ± 0.6 cm of H2O).

Conclusion
These data suggest that use of NIMV induces similar physiologic effects as ETMV, but the nasal cavities and mask contribute greater dead space, manifesting in hypercapnia. Increasing the VT used on a per kilogram of body wieght basis, or the use of pressure-cycled ventilation might reduce hypercapnia during NIMV.

Clinical Relevance
Use of NIMV might be applicable in selected foals, such as those with hypoventilation and minimal changes in lung compliance, during weaning from endotracheal mechanical ventilation, or for short-term ventilation in weak foals. (Am J Vet Res 1997;58:1463–1467)
Clinical effects of porcine reproductive and respiratory syndrome virus on pigs during the early postnatal interval
Authors: Mengeling William L. , Lager Kelly M. , Vorwald Ann C. 
Published: January 2024

SUMMARY

Objective
To determine the effect of congenital and early postnatal infection of pigs with porcine reproductive and respiratory syndrome virus (PRRSV) on postnatal survival and growth.

Animals
20 pregnant gilts and their pigs and fetuses.

Procedure
16 pregnant gilts (principals) comprising 4 groups (4 gilts/group) were exposed oronasally to 4 strains of PRRSV (a vaccine strain, and 3 field strains) at or about day 90 of gestation. Four pregnant gilts (controls) were kept under similar conditions, except for exposure to PRRSV. Samples collected from pigs before ingestion of colostrum and samples and specimens collected from pigs at selected times thereafter were tested for PRRSV and homologous antibody. Pigs were observed for clinical signs and were weighed at birth and at weekly intervals until they were euthanatized and necropsied at about 3 weeks of age.

Results
At least some members of all litters of principal gilts were infected congenitally. Most noninfected, liveborn littermates became infected within the first week of life. Infection of pigs with field strains did, and infection of pigs with the vaccine strain did not, adversely affect postnatal survival and growth rate. All infected pigs had generalized lymph node enlargement.

Conclusion
Exposure of pregnant gilts to either attenuated (vaccine) or virulent (field) strains of PRRSV can result in congenital infection. Vaccine as well as field strains can be transmitted postnatally from infected to noninfected littermates. Pigs infected with field strains have a poorer rate of survival and growth than do noninfected pigs.

Clinical Relevance
Because attenuated (vaccine) PRRSV can cause congenital infection and be transmitted postnatally from congenitally infected to immune-naive pigs, the use of attenuated virus during gestation is, at best, questionable. (Am J Vet Res 1998;59:52–55)
Effects of training on collagen fibril populations in the suspensory ligament and deep digital flexor tendon of young Thoroughbreds
Authors: Patterson-Kane J. C. , Firth E. C. , Parry D. A. D. , Wilson A. M. , Goodship A. E. 
Published: January 2024

SUMMARY

Objective
To determine the effect of a specific galloping exercise regimen on collagen fibril mass-average diameters (MAD) in the deep digital flexor tendon (DDFT) and suspensory ligament (SL) of young Thoroughbreds.

Animals
12 Thoroughbred fillies, 21 ± 1 (mean ± SD) months old.

Procedure
6 horses underwent a specific 18-month treadmill training program involving galloping exercise. The remaining 6 horses served as controls, undertaking low-volume walking exercise over the same period. Sections were excised from the midpoint of the DDFT and SL, and small strips were dissected from central and peripheral locations for each structure. Fibril diameters were measured from micrographs of transverse ultrathin sections, using a computerized image analysis program. An MAD value was calculated for the central and peripheral regions of the DDFT and SL for each horse. Values for both regions were compared between exercised and control horses.

Results
The MAD did not change significantly with exercise for either the DDFT or the SL.

Conclusion
Loading of the DDFT as a result of this exercise regimen was not sufficient to stimulate collagen fibril hypertrophy, in keeping with current data that indicate this tendon, compared with the SL and superficial digital flexor tendon (SDFT), is subjected to low loads. Microtrauma, in terms of reduction in fibril MAD, may have occurred in the SL at a site different from that sampled. Another possibility is that, between the trot and the gallop, loading of the SL does not increase to the same extent as that of the SDFT. (Am J Vet Res 1998;59:64–68)
Effects of hypochlorous acid and ascorbic acid on conductance, permeability, and structure of equine colonic mucosa in vitro
Authors: Inoue Olivia J. , Freeman David E. , Wallig Matthew 
Published: January 2024

SUMMARY

Objectives
To study effects of hypochlorous acid (HOCI) on equine colonic mucosa in vitro, and determine whether addition of ascorbic acid protects against the effects.

Animals
6 healthy horses and ponies.

Procedure
Short-circuit current was measured in mucosa mounted in Ussing chambers. Incubation conditions were: control (no additions); 5 mM HOCI; 1 mM HOCI; same and 5 mM ascorbic acid; 3 mM HOCI; 3 mM HOCI and 5 mM ascorbic acid; 7 mM HOCI; and 7 mM HOCI plus 5 mM ascorbic acid. Permeability was measured with [3H]mannitol and, at the conclusion of each experiment, tissues were examined microscopically to assess the effects of HOCI and ascorbic acid, alone or in combination.

Results
Short circuit current and conductance increased transiently in response to 1 mM HOCI. Tissues had mild surface epithelial damage, as evident by swelling and separation of isolated cells. These changes were abolished when tissues were coincubated with 5 mM ascorbic acid and 1 mM HOCI. At 3 and 7 mM concentrations, HOCI caused marked increase in tissue conductance, short circuit current, and permeability to mannitol; these changes were associated with histologic damage. Again, coincubation with 5 mM ascorbic acid protected against these changes. Additional studies indicated that the effects of HOCI and the protective effects of ascorbic acid were not mediated through changes in pH.

Conclusions
HOCI in low concentrations is capable of increasing the short-circuit current in equine colon, possibly by increasing secretions; however, higher concentrations can cause tissue damage. The addition of 5 mM ascorbic acid blocks these changes.

Clinical Relevance
The concentration of HOCI produced by activated neutrophils could damage equine colonic mucosa and potentially contribute to or cause reperfusion injury. The ability of ascorbic acid to ameliorate this injury in an in vitro setting offers a potential method for pharmacologic evaluation of this injury and for treatment. (Am J Vet Res 1998;59:82–87)
Cell trafficking, mediator release, and articular metabolism in acute inflammation of innervated or denervated isolated equine joints
Authors: Hardy Joanne , Bertone Alicia L. , Weisbrode Steven E. , Muir William W. , O'Dorisio Thomas M. , Masty Jerome 
Published: January 2024

SUMMARY

Objectives
To describe the acute cellular response, inflammatory mediator release, and effect on chondrocyte metabolism of interleukin 1β (IL-1β) in isolated innervated or denervated equine metacarpophalangeal joints.

Animals
One metacarpophalangeal joint of 24 adult horses.

Procedures
The metacarpophalangeal joint was isolated for 6 hours in a pump-perfused, auto-oxygenated, innervated or denervated metacarpophalangeal joint preparation. Isolated joints were assigned to 4 groups: control, control-denervated, inflamed, and inflamed-denervated, and inflammation was induced by intra-articular injection of IL-1β. Synovial fluid was collected for cytologic examination and determination of IL (IL)-1β, (IL-6), prostaglandin E2 (PGE2), and substance P (SP) values. Synovial membrane was immunostained with SP and nerve-specific enolase (NSE) antibodies. Cartilage was collected for determination of proteoglycan (PG) synthesis and degradation.

Results
IL-1β induced significant neutrophilic leukocytosis in synovial fluid and synovial membrane. IL-1β concentration had returned to baseline by 5.5 hours, but IL-6 concentration significantly increased throughout the study. Total SP content was significantly higher in inflamed joints. There was a significant increase in 24- and 48-hour PG degradation in inflamed innervated joints.

Conclusion
Cellular response to IL-1β was rapid and sustained; joint clearance of IL-1β was rapid, and endogenous production of IL-1β did not follow. The IL-6 and PGE2 concentrations significantly increased, and SP content was increased in association with inflammation but not denervation. A degradative response of cartilage to IL-1β was observed, and was enhanced by innervation. This model was useful for investigation of the articular response to acute inflammation and the influence of denervation in modulating this response. (Am J Vet Res 1998;59:88–100)
Cardiopulmonary effects of anesthesia induced and maintained with isoflurane in cats
Authors: Hodgson David S. , Dunlop Colin I. , Chapman Phillip L. , Grandy Jacqueline L. 
Published: January 2024

SUMMARY

Objective
To determine the cardiopulmonary effects of anesthesia induced and maintained with isoflurane (ISO) in cats.

Animals
8 healthy cats between 1 and 5 years old.

Procedure
Anesthesia was induced with ISO in oxygen. Two anesthetic depths were maintained in each cat; mean alveolar concentrations (MAC) were 1.3 and 2.0 times MAC. Ventilation was either spontaneous or controlled. Each cat received each treatment combination according to a Latin square design. Cardiopulmonary measurements were made after 20 minutes of constant conditions with each combination of anesthetic depth and ventilatory mode.

Results
Cardiac index was not different between ISO doses, but 2.0 MAC ISO reduced arterial blood pressure and total peripheral resistance. Cardiac index and systolic arterial blood pressure were reduced by controlled ventilation. The PaCO2 and pulmonary artery pressure were highest in association with 2.0 MAC ISO during spontaneous ventilation. Changes in pHa were attributable to changes in PaCO2.

Conclusions
2.0 MAC ISO causes hypotension and hypercapnia; however, cardiac index is maintained. Hypercapnia may be abolished with controlled ventilation, but at the expense of reduced cardiac index. 1.3 MAC ISO results in minimal cardiopulmonary depression, especially when healthy cats are allowed to breathe spontaneously.

Clinical Relevance
Hypoventilation associated with untoward physiologic responses to 2.0 MAC may be overcome with controlled ventilation, but results in marked reduction in cardiovascular performance; thus, use of 2.0 MAC ISO should be avoided in cats. (Am J Vet Res 1998;59:182–185)
Evaluation of digital and laminar blood flow in horses given a low dose of endotoxin
Authors: Ingle-Fehr J. E. , Baxter G. M. 
Published: January 2024

SUMMARY

Objective
To measure blood flow in the palmar digital artery and laminae corium, using ultrasonic and laser Doppler flowmetry, respectively.

Animals
6 healthy horses.

Procedure
Digital blood flow and laminar perfusion, respectively, were measured by placing a flow probe around the palmar digital artery and a laser Doppler flow probe in a hole in the dorsal aspect of the hoof wall. All horses were given saline (0.9% NaCI) solution (1 L, IV, during a 30-minute period). Seven days later, each horse was given endotoxin (0.1 μg/kg of body weight, IV, in 1 L of saline solution, during a 30-minute period). Digital blood flow, laminar perfusion, heart and respiratory rates, body temperature, and clinical signs of endotoxemia were recorded throughout a 240-minute period. Repeated-measures ANCOVA was used to evaluate changes in outcome variables.

Results
Treatment with saline solution did not cause a change in measured variables. All horses had mild clinical signs of endotoxemia. Endotoxin treatment caused a significant decrease in digital blood flow and increases in heart rate and body temperature. Laminar perfusion decreased after endotoxin treatment.

Conclusions
Endotoxin administration caused a profound transient decrease in digital blood flow and a less substantial decrease in laminar perfusion.

Clinical Relevance
Horses with clinical endotoxemia were likely to have decreased digital blood flow and, possibly, decreased laminar perfusion, potentially predisposing them to vascular alterations within the digits. (Am J Vet Res 1998;59:192–196)
Use of the urine cortisol-to-creatinine ratio for monitoring dogs with pituitary-dependent hyperadrenocorticism during induction treatment with mitotane (o, p'-DDD)
Authors: Randolph John F. , Toomey Jane , Center Sharon A. , Scarlett Janet M. , Reimers Thomas , Graham Peter , Nachreiner Raymond F. 
Published: January 2024

Abstract

Objective
To determine whether the urine cortisol-to-creatinine ratio (UCCR) could replace the ACTH stimulation test in monitoring effectiveness of mitotane induction treatment in dogs with pituitary-dependent hyperadrenocorticism (PDH).

Animals
15 dogs with PDH.

Procedure
All 15 dogs were given an induction dose of mitotane (o, p'-DDD: 35 to 50 mg/kg of body weight/d) for 3 to 14 days. During the induction period, free-catch morning urine samples were collected for determination of UCCR, followed by ACTH stimulation testing, every other day. Treatment response was divided into 3 categories: well-controlled PDH (post-ACTH serum cortisol concentration ≥ 28 nmol/L but ≤ 138 nmol/L), deficient cortisol secretion (post-ACTH serum cortisol concentration < 28 nmol/L), and excess cortisol secretion (post-ACTH serum cortisol concentration > 138 nmol/L).

Results
The linear relation between UCCR and post-ACTH serum cortisol concentration was significant (P < 0.001); however, the prediction intervals surrounding the line were too broad to be clinically useful. The UCCR overlapped among the 3 categories of treatment response. Nevertheless, dogs with PDH receiving mitotane induction treatment and with UCCR > 79 × 10−6 were always classified as having excess cortisol secretion.

Conclusion and Clinical Relevance
The UCCR failed to predict post-ACTH cortisol concentration during mitotane induction treatment sufficiently close to be a clinically reliable indicator of treatment control. Seemingly, however, UCCR > 79 × 10−6 obtained from a dog with PDH during mitotane induction would indicate inadequate adrenal cortex destruction and the need for continued mitotane induction; UCCR ≤ 79 × 10−6 would be inconclusive. (Am J Vet Res 1998;59:258–261)
Effect of α-chymotrypsin on breaking strength and ultrastructural morphology of canine ciliary zonules
Authors: Halenda Ruth Marrion , Nasisse Mark P. , Dykstra Michael J. 
Published: January 2024

Abstract

Objective
To determine the effect of α-chymotrypsin treatment on breaking strength and ultrastructural morphology of canine ciliary zonules.

Sample Population
Eyes from young random-source dogs from an animal shelter.

Procedure
Eyes were obtained immediately after euthanasia of dogs. The enzyme α-chymotrypsin was applied to the ciliary zonules of 1 eye of each dog; the other eye was treated with saline solution as a control. The breaking strength of ciliary zonules was measured, using a linear actuator and force transducer. The lenses and ciliary bodies were then analyzed by scanning and transmission electron microscopy.

Results
α-Chymotrypsin reduced the breaking strength of ciliary zonules by a mean ± SD 44 (± 20)%, compared with that for saline-treated control eyes. Increasing the volume of enzyme further decreased the breaking strength of the zonules. Differences in the appearance of the ciliary body by electron microscopy were not apparent between enzyme- and saline-treated specimens.

Conclusions and Clinical Relevance
Application of α-chymotrypsin to enucleated canine eyes at a concentration used in people significantly reduces the breaking strength of canine ciliary zonules without any apparent damage to the ciliary body. α-Chymotrypsin may be useful in the removal of subluxated canine lenses and in removal of cataractous lenses in young dogs, in which phacoemulsification often results in appreciable post operative capsular opacification. (Am J Vet Res 1998;59:335–339)