bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of the large intestine in the pathogenesis of diarrhea in weaned pigs
Authors: van Beers-Schreurs Hetty Μ. G. , Nabuurs Μ. J. A. , Vellenga L. , Wensing Th. , Breukink H. J.
Published: January 2024

Objective

To determine whether the large intestine may have a role in counterbalancing the loss of fluid from the small intestine of pigs with diarrhea.

Animals

2 groups of pigs (1 from a specific-pathogen-free herd and 1 from a herd with a history of diarrhea).

Procedure

At weaning and 4, 7, 11, and 14 days after weaning, the percentage of dry matter in the large intestinal contents, total and individual concentrations of volatile fatty acids in large-intestinal contents and blood, and concentration of aldosterone in the blood were measured.

Results

Large intestinal contents of pigs with diarrhea had a lower percentage of dry matter, lower acetate and butyrate concentrations, and higher propionate concentrations than did those of specific-pathogen-free pigs, and blood of pigs with diarrhea also had lower total volatile fatty acids concentration, higher aldosterone concentration, and lower sodium concentration.

Clinical Relevance

The large intestine has a role in the pathogenesis of diarrhea in weaned pigs. (Am J Vet Res 1998;59:696-703)
Antibody responses to Pasteurella haemolytica 1:A and three of its outer membrane proteins in serum, nasal secretions, and bronchoalveolar lavage fluid from calves
Authors: Brennan Robert E. , Corstvet Richard E. , Paulson Daniel B.
Published: January 2024

Objective

To determine systemic and mucosal antibody responses in calves to Pasteurella haemolytica 1:A and to 2 major outer membrane proteins (OMP) and 1 major iron-regulated OMP of P haemolytica 1:A.

Animals

23 crossbred calves.

Procedure

2 experiments were performed. In the first experiment, 6 calves were vaccinated and challenge exposed intranasally with an aerosol of P haemolytica 1:A and 6 calves were only challenge exposed. In the second experiment, 8 calves were vaccinated in the area of the tracheal bifurcation with an aerosol of P haemolytica 1:A and 3 calves were used as controls. Serum, nasal secretions, and bronchoalveolar lavage (BAL) samples were collected, and IgG1, IgG2, IgA, and IgM titers were determined. Nasal secretions and BAL samples were also submitted for bacterial culture.

Results

Serum antibody responses in the 2 groups were similar. Antibody titers in nasal secretions and BAL samples increased in calves vaccinated intranasally. In calves vaccinated in the area of the tracheal bifurcation, antibody titers increased in BAL samples but not in nasal secretions. Antibody responses did not correlate with results of bacterial culture.

Conclusions

Results indicated that intranasal administration of P haemolytica 1:A may be a better method for stimulating protective immune responses in the upper portion of the respiratory tract than lung administration. The single dilution ELISA provided a reliable and economical method for determining antibody titers. (Am J Vet Res 1998;59:727-732)
Impaired cytosolic calcium mobilization and aggregation in response to collagen in platelets from Japanese Black cattle with Chediak-Higashi syndrome
Authors: Shiraishi Mitsuya , Ikeda Masahiro , Ogawa Hiroyuki , Tu Chien-Hsien , Ito Katsuaki
Published: January 2024

Objective

To examine whether impaired aggregation of platelets from Japanese Black cattle with Chediak-Higashi syndrome (CHS) was attributable to mobilization of cytosolic Ca2+.

Animals

4 healthy Japanese Black cattle and 3 Japanese Black cattle with CHS.

Procedure

Aggregation and mobilization of cytosolic Ca2+ in response to various receptor agonists was measured in platelets from healthy cattle and cattle with CHS. Involvement of endogenous ADP and arachidonic acid in collagen-induced responses was examined. Cytosolic Ca2+ concentration was measured after platelets were loaded with the Ca2+ indicator fura-PE3. Platelet aggregation was measured with an aggregometer.

Results

Collagen (3 to 15 μg/ml)-induced increases in cytosolic Ca2+ concentration and aggregation were markedly impaired for platelets from cattle with CHS, compared with values for platelets from healthy cattle. Although aggregation and the sustained phase of the cytosolic Ca2+ response to ADP were also decreased in platelets from cattle with CHS, these decreases were small, compared with those in response to collagen. A cyclooxygenase inhibitor and a phospholipase A2 inhibitor did not have any effect on peak cytosolic Ca2+ concentration or collagen-induced aggregation of platelets from healthy cattle. Responses to a P2T-purinoceptor antagonist suggested that decreased release of endogenous ADP was only partially involved in the impaired response to collagen among platelets from cattle with CHS.

Conclusions and Clinical Relevance

Marked inhibition of collagen-induced Ca2+ mobilization, rather than decreased release of endogenous substances, appeared to be the major cause of impaired platelet response to collagen and the hemorrhagic tendency in cattle with CHS. (Am J Vet Res 1998;59:744-749)
Changes in sulfation patterns of chondroitin sulfate in equine articular cartilage and synovial fluid in response to aging and osteoarthritis
Authors: Brown Murray P. , West Leigh A. , Merritt Kelly A. , Plaas Anna H. K.
Published: January 2024

Objectives

To determine effects of aging on sulfation of chondroitin sulfate (CS) in articular cartilage and synovial fluid from normal equine middle carpal joints, and to determine whether CS compositional analysis can be used to assess alterations in proteoglycan turnover in degenerative cartilage obtained from horses with carpal osteochondral fractures.

Sample Population

Carpal articular cartilage and synovial fluid from 44 cadavers with normal joints and from 16 Thoroughbred racehorses during routine carpal arthroscopic surgery.

Procedure

After papain/chondroitinase digestion of cartilage, CS disaccharides (unsulfated disaccharide ΔDi0S, and monosulfated disaccharides ΔDi4S and ΔDi6S) were quantified by capillary zone electrophoresis. The CS was purified from synovial fluid chondroitinase digested, and analyzed. The CS nonreducing terminal residues, N-acetylgalactosamine (galNAc) or glucuronic acid adjacent to a 4-sulfated or 6-sulfated galNAc, were quantified.

Results

In cartilage, the ΔDi6S-to-ΔDi4S ratio increased with age; in degenerative cartilage, this ratio was not significantly different from the normal value. Percentage of ΔDi0S decreased with age and was significantly higher in degenerative than in normal cartilage. The galNAc4S and galNAc4,6S represented > 96% of the terminal residues. There was a significant decrease in 6-sulfation of the terminal residues in degenerative cartilage.

Conclusions

6-Sulfation of internal and terminal CS residues increased with age. Cartilage degeneration in racehorses was accompanied by deposition of CS chains with altered sulfation patterns. In normal and diseased joints of horses > 2 years old, synovial fluid CS was not indicative of cartilage CS and may represent turnover products of a subpopulation of proteoglycan within the matrix. (Am J Vet Res 1998;59:786-791)
Clinical, urodynamic, and histologic effects of urethral intussusception in clinically normal dogs
Authors: Bertrand Scott G. , Bellah Jamie R. , Ginn Pamela E.
Published: January 2024

Objective

To evaluate clinical and histologic effects of surgically created urethral intussusception and determine whether it creates a high-pressure zone that resists passive urine flow in clinically normal dogs.

Animals

8 healthy adult sexually intact female dogs.

Procedure

Urethral pressure profilometry was used to measure maximal urethral closure pressure (MUCP) and functional profile length (FPL) in dogs sedated with xylazine hydrochloride and atropine before and 2, 4, 7, 14, 28, 60, and 90 days after surgery. Cystourethral leak point pressure (CLPP) and cystourethral leak point volume (CLPV) were determined in anesthetized dogs immediately before and after surgery. Dogs were assigned to 4 groups of 2 dogs each; groups were euthanatized 4, 14, 28, and 90 days later, and representative tissues were examined.

Results

Dog 1 developed complete postoperative urethral obstruction. The procedure was altered, and all dogs recovered without complication. Mild inflammation attributable to surgical manipulation, but not ischemic damage or reduction of the intussusception, was evident. Comparison of preoperative MUCP and FPL with postoperative values did not yield significant differences. Immediate postoperative CLPP and CLPV were significantly higher than preoperative values, but were not significantly increased at euthanasia. A distinct but nonsignificant pressure spike was observed in postoperative urethral pressure profiles and persisted in 7 of 8 dogs.

Conclusions

Urethral intussusception does not have deleterious effects when performed as described. Urodynamic data do not support the premise that urethral intussusception will create a high-pressure zone in the urethra that will resist passive urine flow long term in clinically normal dogs. (Am J Vet Res 1998;59:904–912)
Evaluation of a hand-held electrical conductivity meter for detection of subclinical mastitis in cattle
Authors: Musser Jeffrey M. B. , Anderson Kevin L. , Caballero Magaly , Amaya Daniel , Maroto-Puga Jorge
Published: January 2024

Objective

To assess, under field conditions, whether a hand-held electrical conductivity (EC) meter could be used to detect subclinical mastitis caused by pathogens most commonly associated with mastitis in dairy cows.

Animals

425 lactating cows on 15 dairies in Costa Rica.

Procedure

Immediately prior to milking, milk samples from each quarter were tested, using a hand-held EC meter. A milk sample from the quarter with the highest score was submitted for bacteriologic culture. Results of bacteriologic culture were compared with highest absolute EC score for each cow and with differential EC score (ie, difference between the highest and lowest absolute EC scores for the 4 quarters of each cow).

Results

Absolute EC score for cows with subclinical mastitis was significantly higher than that for cows without subclinical mastitis, and absolute EC score was significantly associated with detection of subclinical mastitis. If absolute EC score ≥ 7 was considered indicative of subclinical mastitis, sensitivity was 0.43, specificity was 0.83, predictive value of a positive result was 0.39, and predictive value of a negative result was 0.85. Differential EC score for cows with mastitis was significantly higher than that for cows without subclinical mastitis. If differential EC score ≥ 2 was considered indicative of subclinical mastitis, sensitivity was 0.53, specificity was 0.77, predictive value of a positive result was 0.37, and predictive value of a negative result was 0.87.

Clinical Implications

A hand-held EC meter may be used to screen cows for subclinical mastitis. (Am J Vet Res 1998;59:1087-1091)
Development of a simple enzyme immunoassay for blood haptoglobin concentration in cattle and its application in improving food safety
Authors: Saini P. K. , Riaz M. , Webert D. W. , Eckersall P. D. , Young C. R. , Stanker L. H. , Chakrabarti E. , Judkins J. C.
Published: January 2024

Objective

To verify the role of haptoglobin, a major acute-phase reactant protein in cattle, as a marker to identify health/disease status in cattle and further assess its potential in improving food safety.

Sample Population

Serum samples from various cattle groups: clinically normal cattle comprising steers (n = 157) and culled dairy cows (n = 92) before death (antemortem [AM]); retained carcasses (n = 57) railed off the line during postmortem (PM) inspection; and apparently AM normal culled dairy cows (n = 57).

Procedure

-Efficacy of the simplified monoclonal antibody-based enzyme immunoassay was established by comparing results of haptoglobin tests performed independently on aliquots of serum samples by 3 laboratories.

Results

Haptoglobin concentration was significantly (P ≤ 0.0001) different between the PM retained carcass group (n = 57) and the AM steer (n = 157) and culled dairy cow (n = 92) groups. In addition, haptoglobin concentration in AM steers (n = 157) and culled dairy cows (n = 92) was significantly (P < 0.0012) different, possibly reflecting a higher percentage of underlying pathologic or inflammatory conditions in animals of the latter group. Evaluation in 3 laboratories of sera from a group of culled dairy cows (n = 57), each laboratory performing a different test procedure, indicated that correlation of haptoglobin concentrations was good between the reported test procedure and the unmodified test and the classical hemoglobin-binding assay that measures peroxidase activity.

Conclusion

Haptoglobin determination is effective in identifying diseased and healthy cattle. It may be a potentially important tool for application at the farm and slaughterhouse as an aid in improving food safety. (Am J Vet Res 1998;59:1101-1107)
Evaluation of periparturient dairy cows and contact surfaces as a reservoir of Cryptosporidium parvum for calfhood infection
Authors: Atwill Edward R. , Harp James A. , Jones Ted , Jardon Phillip W. , Checel Stephanie , Zylstra Mike
Published: January 2024

Objective

To determine whether periparturient cows or contact surfaces to which newborn calves are exposed are reservoirs of Cryptosporidium parvum oocysts.

Animals

Periparturient cows and their calves.

Procedure

Using direct fluorescent antibody (DFA) and acid-fast (AF) assays, fecal samples taken before and after calving from periparturient cows were tested for C parvum oocysts. Fecal samples from calves were collected every other day from age 7 to 21 days and were tested by use of the AF assay. Topsoil from close-up and maternity pens and scrapings from wooden walls and floors of calf hutches were tested for C parvum oocysts by use of DFA assay.

Results

None of the 384 fecal samples obtained 1 to 21 days before or after calving or on the day of calving from 154 periparturient cows contained detectable C parvum oocysts. Despite this lack of detectable periparturient shedding, the period prevalence of calfhood infection was 92% (123/134) from age 7 to 21 days. Soil samples from the close-up and maternity pens where newborn calves spend the first 12 hours of life also were negative for C parvum oocysts. Wood scrapings from the outer 2 mm of the walls and floors of empty and cleaned calf hutches that were ready to receive calves were C parvum oocyst-positive.

Conclusions

Conditional on sensitivity of DFA, periparturient cows did not appear to shed detectable C parvum oocysts. In contrast, the floors and walls of wooden calf hutches contained detectable C parvum oocysts on the surface. (Am J Vet Res 1998;59:1116-1121)
Histamine-induced adherence and migration of equine eosinophils
Authors: Foster A. P. , Cunningham F. M.
Published: January 2024

Objectives

To examine effects of histamine on equine eosinophil adherence in vitro and to determine the histamine receptor subtype(s) and cell surface adhesion molecules that mediate this response. In addition, to determine the receptor subtypes involved in histamine-induced eosinophil migration.

Animals

8 healthy ponies.

Procedure

Effects of histamine on equine eosinophil adherence to serum- or fibronectin-coated plastic, and migration in a microchemotaxis assay were examined. In some experiments, eosinophils were pretreated with histamine receptor antagonists or monoclonal antibodies raised against cell adhesion molecules. For comparison, the effect of histamine on equine neutrophil adherence and migration was studied.

Results

Histamine induced adherence of equine eosinophils, but not neutrophils, to serum- and fibronectin-coated plastic (P < 0.01). Histamine also caused migration of equine eosinophils, but not neutrophils (P < 0.01). Histamine-induced adherence and migration of equine eosinophils were inhibited by histamine, (H1)-receptor antagonists chlorpheniramine and mepyramine (P < 0.01 ), but not H2- or H3-receptor antagonists cimetidine and thioperamide. Monoclonal antibodies raised against CD18, but not very late antigen 4, reduced histamine-induced equine eosinophil adherence to serum- and fibronectin-coated plastic (P < 0.01).

Conclusions

When released from mast cells or basophils, histamine could stimulate adherence and migration of equine eosinophils via H1 receptor activation and induce adherence of equine eosinophils to opsonized surfaces or dermal connective tissue matrix proteins via CD18 activation.

Clinical Relevance

Histamine may have a part in regulating equine eosinophil function during parasitic killing or antigen-induced responses in horses with insect hypersensitivity. (Am J Vet Res 1998;59:1153— 1159)
Evaluation of treatment with a pulsed electromagnetic field on wound healing, clinicopathologic variables, and central nervous system activity of dogs
Authors: Scardino M. Stacie , Swaim Steven F. , Sartin Eva A. , Steiss Janet E. , Spano Joseph S. , Hoffman Charles E. , Coolman Shindok L. , Peppin Barbara L.
Published: January 2024

Objective

To evaluate effects of treatment with a pulsed electromagnetic field (PEMF) on healing of open and sutured wounds, clinicopathologic variables, and CNS activity of dogs.

Animals

12 adult female Beagles.

Procedure

Open and sutured wounds were created in the skin of the trunk of the dogs. Dogs were divided into 2 groups. One group received PEMF treatment and 1 group served as untreated (control) dogs. The PEMF-treated dogs received treatment twice a day starting the day before surgery and lasting through day 21 after surgery. Wounds were evaluated by use of tensiometry, planimetry, laser Doppler perfusion imaging, and histologic examination. Clinicopathologic variables and electroencephalographic tracings were also evaluated.

Results

Use of PEMF treatment resulted in significantly enhanced epithelialization of open wounds 10 and 15 days after surgery. Five days after surgery, wounds of control dogs had a negative value for wound contraction, whereas PEMF-treated wounds had a positive value. The PEMF treatment did not cause significant changes in short-term planimetric, perfusion, tensiometric, histologic, clinicopathologic, or electroencephalographic results.

Conclusions

The PEMF treatment enhanced wound epithelialization in open cutaneous wounds and provided indications of early contraction without significant short-term changes in other variables. (Am J Vet Res 1998;59:1177-1181)
Isolation and chondrocytic differentiation of equine bone marrow-derived mesenchymal stem cells
Authors: Fortier Lisa A. , Nixon Alan J. , Williams Janice , Cable Christina S.
Published: January 2024

Objective

To isolate mesenchymal stem cells from adult horses and determine specific monolayer culture conditions required to enhance biochemically and phenotypically defined chondrocytic differentiation.

Animals

2 adult horse bone marrow donors without skeletal or hematologic abnormalities.

Procedure

Bone marrow was aspirated from the sternebra, and mesenchymal stem cells were isolated by centrifugation and cultured in monolayers. Subcultures were established in 24-well plates on day 13. Culture medium was harvested every 2 days, and culture of 12 of the 24 wells was terminated on day 6 and of the remaining wells on day 12. Medium proteoglycan content was determined for all samples, and proteoglycan monomeric size was determined for pooled samples from days 2-6 and 8-12. Total nucleated cell numbers were determined at culture termination on days 6 and 12. Histologic, histochemical, and collagen immunohistochemical analyses of multiwell chamber slides harvested on day 6 or 12 were performed.

Results

Mesenchymal cells were an abundant cellular constituent of bone marrow aspirates, and separation of hematopoietic elements was achieved by centrifugation and delayed medium exchange. The remaining mesenchymal stem cells progressed from large, spindyloid, fibroblastic-appearing cells to a rounder shaped cell which formed colony plaques; isolated cells remained more spindyloid. Mesenchymal cell transformation toward a chondrocytic phenotype was verified by a shift in expression from collagen type I to type II, and an increase in quantity and molecular size of proteoglycans synthesized over time.

Conclusions

Mesenchymal stem cells obtained from adult horses have the capacity to undergo chondrogenic differentiation in monolayer cultures and may provide a locally recruitable or transplantable autogenous cell source for articular cartilage repair. (Am J Vet Res 1998;59:1182-1187).
Effect of three types of half-limb casts on in vitro bone strain recorded from the third metacarpal bone and proximal phalanx in equine cadaver limbs
Authors: Schneider Robert K. , Ratzlaff Marc C. , White Karl K. , Hopper Scott A.
Published: January 2024

Objective

To determine effect of 3 half-limb casts on bone strains recorded from the proximal phalanx (P-1) and third metacarpal bone (MCIII) of equine cadaver limbs, using a mechanical testing machine.

Animals

12 equine cadaver limbs and 4 live horses.

Procedure

Bone strains were recorded at middorsal P-1 and the dorsal cortical aspect of the distal third of MCIII while limbs were variably loaded with 100 to 1,000 lb of force. To determine ability of the cast to protect the distal portion of the limb from weight-bearing loads, strains were recorded with the limb in 1 of the 3 casts and with it unsupported. To determine cast-induced discomfort, weight-supporting and transfixation pin casts were evaluated on 2 live horses

Results

All 3 casts significantly reduced bone strain at P-1. Significant differences were observed: mean 61 % reduction for the standard half-limb cast, 84% for the transfixation pin cast, and 97% for the weight-supporting cast at weight-bearing force of 500 lb. Only the weight-supporting cast significantly reduced strains recorded from MCIII. The weight-supporting cast was not well tolerated by 2 live horses.

Conclusions

The 3 casts significantly reduced transfer of weight-bearing forces to the distal portion of the limb. The weight-supporting cast effectively reduced strain on the P-1 to near 0, but was well tolerated by live horses. The transfixation pin cast reduced strain on the P-1 by > 80% at weight-bearing loads of 500 lb, and live horses were comfortable. Standard half-limb casts significantly reduced strains on the P- 1, but to a lesser degree than did other casts. (Am J Vet Res 1998;59:1188-1193)
Morphometric analysis of endometrial periglandular fibrosis in mares
Authors: Evans T. J. , Miller M. A. , Ganjam V. K. , Niswender K. D. , Ellersieck M. R. , Krause W. J. , Youngquist R. S.
Published: January 2024

Objectives

To develop an objective, quantifiable assay for endometrial periglandular fibrosis (EPF) and correlate assay results with histologic and ultrastructural changes in equine endometrial biopsy specimens.

Sample Population

Endometrial biopsy specimens from 70 mares from 3 to 27 years old in estrus.

Procedure

In a double-blinded study design, endometrial biopsy specimens were graded histologically (modified Kenney classification) for EPF and inflammation. Endometrial periglandular collagen volume fraction (%EPCVF) was determined by light microscopic image analysis of picrosirius red-stained sections. Specimens from selected mares were examined by transmission electron microscopy.

Results

%EPCVF values varied significantly among the 4 modified Kenney EPF categories (I, IIA, IIB, and III) and increased with increasing age of mares. Morphologically, EPF consisted of concentric layers of transformed fibroblasts with myofibroblastic features and deposition of fibrillar collagen around unaltered glandular basal laminae.

Conclusions and Clinical Relevance

%EPCVF correlates well with morphologic changes in endometrial biopsy specimens. Determination of %EPCVF could be useful in evaluation and clinical management of subfertile mares and in investigations of the pathogenesis of EPF. (Am J Vet Res 1998;59:1209-1214)
Shear-induced platelet activation and platelet-neutrophil aggregate formation by equine platelets
Authors: Weiss Douglas J. , Evanson Oral A. , McClenahan David , Fagliari José , Walcheck Bruce
Published: January 2024

Objectives

To determine whether platelets become activated and form platelet-platelet or platelet-neutrophil aggregates, or both, when subjected to shear.

Sample Population

Blood obtained from 3 Thoroughbreds.

Procedures

Blood, with PCV adjusted to 32 (low hematocrit) or 60 (high hematocrit)%, was subjected to shear rates of 11.25, 22.5, 45, 90, 225, and 750/s for 3 minutes by use of a cone-plate viscometer. Flow cytometric techniques were used to identify activated platelets, platelet-platelet aggregates, and platelet-neutrophil aggregates.

Results

Shear resulted in decreased platelet count, increased mean platelet volume, platelet activation, and formation of platelet-platelet and platelet-neutrophil aggregates. These changes occurred at lower shear rates in blood with high hematocrit. Platelet-neutrophil aggregate formation was inhibited by blocking P-selectin, but not CD11/CD18 receptors.

Conclusions

Shear-induced platelet activation and aggregate formation occur at physiologic shear rates.

Clinical Relevance

Shear-induced platelet activation may explain the exercise-associated platelet-neutrophil aggregates observed in Thoroughbreds undergoing treadmill exercise. (Am J Vet Res 1998;59:1243-1246)
Sequence and structural analysis of feline interleukin-5 cDNA
Authors: Padrid Philip A. , Qin Yimin , Wells T. N. C. , Solway Julian , Camoretti-Mercado Blanca
Published: January 2024

Objective

To clone and characterize the cDNA encoding feline interleukin-5 (IL-5) cDNA and the 170 basepairs (bp) of the 5' flanking region of the feline IL-5 gene.

Sample Population

Blood mononuclear cells from a healthy cat.

Procedures

Cells were cultured, stimulated for 48 hours with concanavalin A, and harvested for RNA and DNA isolation. Recovered RNA was used in northern blot and reverse transcription-polymerase chain reaction analyses. Resulting cDNA was used for rapid amplification of 3' cDNA ends, dideoxy chain termination sequencing, and primer extension analysis.

Results

Full length cDNA was 838 bp, including a 402-bp open reading frame that encoded a precursor protein of 134 amino acids including a putative peptide signal of 19 residues. Homologies of the nucleotide and derived protein sequences between feline and human IL-5 cDNA were 72 and 71%, respectively. There also was homology between the human and predicted feline cytokines at amino acid positions that are critical for IL-5 receptor binding and signal transduction. The 5' flanking region of the feline gene was homologous to corresponding regions of the human (88%) and murine (72%) genes, and included putative transcriptional regulatory elements.

Conclusions and Clinical Relevance

Identification of feline IL-5 cDNA is an important step toward a detailed, fully comprehensive characterization of the mechanisms that may be operative in the pathogenesis of eosinophilic disorders in cats. The striking homology between the human and feline IL-5 genes suggests that cats can be used as animal models for human diseases characterized by eosinophil infiltration of tissues. (Am J Vet Res 1998;59:1263–1269)
Local hemodynamics, permeability, and oxygen metabolism during acute inflammation of innervated or denervated isolated equine joints
Authors: Hardy Joanne , Bertone Alicia L. , Muir William W.
Published: January 2024

Objectives

To determine oxygen metabolism, permeability, and blood flow in isolated joints in response to interleukin 1β (IL-1β) and contribution of innervation.

Sample Population

One metacarpophalangeal (MCP) joint of 24 adult horses.

Procedure

The MCP joint was isolated for 6 hours in a pump-perfused, auto-oxygenated, innervated or denervated preparation. Isolated joints were assigned to the following 4 groups: control, control-denervated, inflamed, and inflamed-denervated, and inflammation was induced by intra-articular injection of IL-1β. Circuit arterial and venous pressures, flows, and blood gas tensions, synovial fluid production, and intra-articular pressure were measured. Total vascular resistance; oxygen delivery, consumption, and extraction ratio (ER); and permeability surface area product were calculated. Synovial membrane blood flow was determined at 0, 60, and 330 minutes. Synovial membrane wet-to-dry ratio was obtained, and permeability to macromolecules was determined by intra-articular injection of Evans blue albumin and fluorescein isothiocyanate-conjugated dextran.

Results

Oxygen delivery and synovial membrane blood flow progressively increased but were not different among groups. Oxygen consumption and ER significantly increased in inflamed joints, as did intraarticular pressure and synovial fluid production. Inflamed joints had greater wet-to-dry ratio. Albumin permeability significantly increased in the villous synovial membrane of the inflamed groups, and dextran permeability was increased in the innervated groups, with a trend toward increased permeability in inflamed groups.

Conclusion

Inflammation significantly increased oxygen demand, which was initially met by increased ER. Permeability to small molecules was increased with inflammation; innervation increased permeability to large molecules. Use of an isolated joint model enabled documentation of the physiologic responses of the joint to acute inflammation. (Am J Vet Res 1998;59:1307–1316)
Functional responses of neonatal chicken and turkey heterophils following stimulation by inflammatory agonists
Authors: Kogut Michael H. , Holtzapple Carol , Lowry Virginia K. , Genovese Kenneth , Stanker Larry H.
Published: January 2024

Objective

To determine functional responses of neonatal chicken and turkey heterophils to various inflammatory agonists.

Animals

100 one-day-old chickens and turkeys.

Procedure

Blood heterophils were isolated and stimulated for 30 minutes at 39 C with ionomycin, phorbol myristate acetate (PMA), opsonized zymosan (OZ), or formyl-methionyl-leucyl-phenylalanine (FMLP). Functional responses (shape change, adherence, phagocytosis, influx of intracellular calcium, and oxidative burst) of stimulated heterophils were measured and compared with responses of unstimulated (control) heterophils.

Results

Turkey and chicken heterophils did not respond to FMLP stimulation. Stimulation of chicken and turkey heterophils with ionomycin resulted in significant increases in adherence, percentage of cells with a shape change, phagocytosis, intracellular calcium concentration, and oxidative burst. Turkey heterophils did not respond to PMA stimulation, whereas stimulation of chicken heterophils with PMA resulted in significant increases in adherence, percentage of cells with a shape change, phagocytosis, and oxidative burst but not intracellular calcium concentration. Stimulation of chicken and turkey heterophils with OZ resulted in significant increases in oxidative burst.

Conclusions

Mechanisms regulating initiation of heterophil activation in neonatal chicken and turkey heterophils are consistent with those described for heterophils isolated from mature birds. The biochemical and cytoskeletal systems of neonatal avian heterophils undergo functional alterations following stimulation with inflammatory agonists.

Clinical Relevance

Understanding heterophil activation and regulation should eventually lead to methods for controlling bacterial diseases in poultry. (Am J Vet Res 1998;59:1404–1408)
Effect of concurrent experimentally induced bovine respiratory syncytial virus and bovine viral diarrhea virus infection on respiratory tract and enteric diseases in calves
Authors: Brodersen Bruce W. , Kelling Clayton L.
Published: January 2024

Objective

To compare experimentally induced concurrent bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV) infection with single virus infection.

Animals

9- to 12-month-old calves.

Procedure

Calves were allotted to 4 groups: 1, mock-infected control (n = 3); 2, BRSV infected (5); 3, BVDV infected (5); and 4, concurrent BRSV and BVDV infected (5). Total and differential WBC counting was done. Concentration and duration of BVDV in nasal secretions and serum, and duration of BRSV in nasal secretions were determined. Concentration of BVDV in various tissues was determined, and isolation of BRSV from lung tissue was attempted. Histologic examination and immunohistochemical analysis were done to detect lesions and distribution of viral antigens, respectively.

Results

Calves with concurrent infection developed more severe clinical signs of disease (fever and diarrhea), leukopenia, and more severe lesions. They also shed virus from nasal secretions in greater concentration and for longer duration, and BRSV was isolated from their lungs. Calves with concurrent infection also had more extensive lung lesions. Alimentary epithelial necrosis and severe lymphoid depletion were associated with BVDV infection in calves with or without concurrent BRSV infection. BVDV antigen in lymphatic tissue was detected in stromal cells only.

Conclusions

Concurrent infection with BRSV and BVDV resulted in more severe respiratory tract and enteric disease than did infection with either virus alone, possibly indicating synergistic effect between the viruses. BVDV’s role in causing respiratory tract disease is attributable, indirectly, to effects on the host’s immune system, not to infection of the lungs. (Am J Vet Res 1998;59:1423–1430)
Pharmacokinetics of multiple-dose administration of eltenac in horses
Authors: Dyke T. M. , Sams R. A. , Thompson K. G. , Ashcraft S. M.
Published: January 2024

Objective

To compare pharmacokinetics of eltenac after first and last IV administrations (0.5 mg/kg), using a multiple dosing schedule.

Animals

6 adult mares.

Procedure

Eltenac (50 mg/ml) was administered IV at a dosage of 0.5 mg/kg of body weight every 24 hours for days 0 through 4. On days 0 and 4, blood samples were collected before, then periodically for 8 hours after eltanac administration. Concentration of eltenac in plasma samples was determined by use of high-performance liquid chromatography.

Results

On day 0, median area under the plasma eltenac concentration versus time curve (AUC) was 6.77 μg•h/ml (range, 5.61 to 8.08 μg•h/ml), median plasma clearance was 1.23 ml/min/kg (range, 1.03 to 1.40 ml/min/kg), and median steady-state volume of distribution was 191 ml/kg (range, 178 to 218 ml/kg). Median terminal half-life of eltenac was 2.36 hours (range, 2.30 to 2.98 hours). On day 4, median eltenac AUC was 6.70 μg•h/ml (range, 5.21 to 7.44 μg•h/ml), median plasma clearance was 1.23 ml/min/kg (range, 1.12 to 1.53 ml/min/kg), and median steady-state volume of distribution was 193 ml/kg (range, 172 to 205 ml/kg). Median terminal half-life of eltenac was 2.40 hours (range, 2.11 to 3.25 hours). Protein binding of eltenac, determined by ultrafiltration, was > 99% at a total plasma concentration of 36 μg/ml.

Conclusion

Pharmacokinetic variables determined for each horse were not different between days 0 and 4.

Clinical Relevance

Under conditions of this study, there was no clinically relevant accumulation of eltenac in equine plasma or alteration of pharmacokinetic variables after multiple IV dosing of 0.5 mg/kg of eltenac. (Am J Vet Res 1998;59:1447–1450)
Pharmacokinetics of thiamphenicol in dogs
Authors: Castells Glòria , Intorre Luigi , Franquelo Carme , Cristòfol Carles , Pérez Belén , Martí Gabriel , Arboix Margarita
Published: January 2024

Objective

To determine pharmacokinetic parameters of thiamphenicol (TAP) after IV and IM administration in dogs.

Animals

6 healthy 2- to 3-year-old male Beagles.

Procedure

In a crossover design study, 3 dogs were given TAP IV, and 3 dogs were given TAP IM, each at a dosage of 40 mg/kg of body weight. Three weeks later, the same dogs were given a second dose by the opposite route. At preestablished times after TAP administration, blood samples were collected through a catheter placed in the cephalic vein, and TAP concentration was determined by use of a high-performance liquid chromatography.

Results

Kinetics of TAP administered IV were fitted by a biexponential equation with a rapid first disposition phase followed by a slower disposition phase. Elimination half-life was short (1.7 ± 0.3 hours), volume of distribution at steady state was 0.66 ± 0.05 L/kg, and plasma clearance was 5.3 ± 0.7 ml/min/kg. After IM administration, absorption was rapid. Peak plasma concentration (25.1 ± 10.3 μg/ml) was reached about 45 minutes after drug administration. The apparent elimination half-life after IM administration (5.6 ± 4.6 hours) was longer than that after IV administration probably because of the slow absorption rate from the muscle. Mean bioavailability after IM administration was 96 ± 7%.

Conclusion

The pharmacokinetic profile of TAP in dogs suggests that it may be therapeutically useful against susceptible microorganisms involved in the most common infections in dogs, such as tracheobronchitis, enterocolitis, mastitis, and urinary tract infections. (Am J Vet Res 1998;59:1473–1475)
Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells
Authors: Braden T. D. , Fry C. , Sartin J. L.
Published: January 2024

Objective

To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells.

Sample Population

Cells from pituitary glands collected from 8- to 14-month-old wethers.

Procedure

Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1α, IL-1β, and IL-2), tumor necrosis factor-α (TNF), and interferon-γ (IFN-γ). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1α and IL-1β.

Results

Similar to effects of endotoxin, IL-1α and IL-1β stimulated release of LH. Interleukin 2, TNF, and IFN-γ did not have a detectable effect on release of LH. Stimulation of LH release by IL-1αand IL-1β required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C.

Conclusions

IL-1αand IL-1β may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-γ do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin.

Clinical Relevance

Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function. (Am J Vet Res 1998;59:1488–1493)
Chromogenic assays for equine coagulation factors VII, VIII:C, IX, and X, and C1-esterase inhibitor
Authors: Topper Michael J. , Prasse Keith W.
Published: January 2024

Objectives

To adapt manual human chromogenic assays for coagulation factors VII (F.VII), VIII:coagulant (F.VIII:C), IX (F.IX), and X (F.X), and C1-esterase inhibitor (C1-INH) for use with an automated analyzer, and to measure the activity of these proteins in horses.

Animals

10 healthy horses were used to determine ranges for the assays. Pooled plasma for standards was collected from an additional 20 healthy horses.

Procedure

A computer-assisted analyzer was programmed from the manual method for commercially available human F.VII, F.VIII:C, F.IX, F.X, and C1-INH chromogenic assay kits. Standards were prepared from pooled citrated equine plasma for the F.VII, F.VIII:C, and F.X assays, and from commercial pooled citrated human plasma for F.IX and C1-INH assays.

Results

Mean ± SD activities in citrated equine plasma from 10 horses were 226 ± 19% for F.VII; 209 ± 31% for F.VIII:C; 149 ± 38% for F.IX; 88 ± 12% for F.X; and 18.4 ± 8.4% for C1-INH. Intra-assay coefficients of variation (CV) were 5.3% for F.VII; 2.1% for F.VIII:C; and 3.0% for C1-INH. Interassay CV were 5.7% for F.VII; 7.4% for F.VIII:C; 3.8% for F.IX; 14.4% for F.X; and 22.0% for C1-INH.

Conclusions

Human chromogenic assay kits can be automated and used to measure F.VII, F.VIII:C, F.IX, F.X, and C1-INH activities in citrated equine plasma.

Clinical Relevance

Human chromogenic assays can be routinely used to measure F.VII, F.VIII:C, F.IX, F.X, and C1-INH in horses, and may be useful in evaluation of horses with disorders of hemostasis. (Am J Vet Res 1998;59:538–541)
Cardiopulmonary effects of propofol and a medetomidine-midazolam-ketamine combination in mallard ducks
Authors: Machin Karen L. , Caulkett Nigel A.
Published: January 2024

Objective

To compare safety of propofol with a medetomidine-midazolam-ketamine (MMK) combination as an anesthetic agent in mallard ducks.

Animals

12 healthy adult female mallard ducks.

Procedure

Each duck was anesthetized twice in a crossover study design with 5 days between randomized treatments. Ducks were given medetomidine (50 μg), midazolam (2 mg), and ketamine (10 mg) in combination, IV, or propofol (10 mg, IV, followed by 1- to 4-mg boluses). Systolic, diastolic, and mean arterial pressures, heart and respiratory rates, and esophageal temperature were recorded before anesthesia and every 5 minutes after induction for 30 minutes, and at 5 minutes after reversal with atipamezole (250 μg) and flumazenil (25 μg; MMK group) or last bolus (propofol group). Arterial blood samples from 8 ducks were collected before anesthesia, 5, 10, 15, 30 minutes after induction, and after reversal or last bolus.

Results

8 ducks survived the MMK anesthesia; 1 duck died and 3 ducks required resuscitation to prevent death. All ducks survived propofol anesthesia. Ducks anesthetized with either anesthetic agent had a significant increase in arterial carbon dioxide tension and decrease in arterial oxygen tension, arterial pH, and esophageal temperature. Ducks given MMK had a decrease in mean arterial pressure and respiratory rate, whereas ducks given propofol had an increase in respiratory rate. Rapid reversal of the effects of MMK was achieved with atipamezole and flumazenil. All physiologic variables, except esophageal temperature in the propofol group, returned to approximate baseline values after reversal or last bolus.

Conclusions

The MMK combination is unsafe for use in ducks. Ducks can be anesthetized safely with propofol but should be monitored and ventilated artificially. (Am J Vet Res 1998;59:598–602)
Culture and characterization of equine terminal arch endothelial cells and hoof keratinocytes
Authors: Wunn Denise , Wardrop K. Jane , Meyers Kenneth , Kramer John , Ragle Claude
Published: January 2024

Objectives

To develop methods to isolate, culture, and characterize equine hoof endothelial cells (EC) and keratinocytes.

Sample Population

Cells harvested from the forelimbs of 8 horses.

Procedure

EC were obtained via catheters placed in the palmar digital arteries of the disarticulated lower portion of the forelimbs from 4 horses that had been heparinized prior to euthanasia. Phosphate-buffered saline solution was used to remove and discard RBC from blood vessels, and collagenase was used to loosen and flush EC from the vasculature. Hoof keratinocytes were obtained from 4 recently euthanatized horses by use of dispase/trypsin dissociation of the coronary band epidermis. Use of an extracellular matrix gel as a culture flask attachment factor was important to the success of hoof keratinocyte cultures.

Results

EC from the palmar digital arteries were successfully cultured and characterized by in vitro morphology, uptake of a fluorescence-labeled acetylated-low density lipoprotein, and lack of expression of von Willebrand factor and smooth muscle actin. Hoof keratinocytes were characterized by morphology in culture and expression of keratin proteins, as determined by immunochemical reaction. Keratinocyte cultures were also positive for vimentin expression.

Conclusions

Culture techniques to isolate and characterize hoof cells should aid investigators in their study of equine hoof pathobiologic features, especially as it relates to laminitis. (Am J Vet Res 1999;60:128–132)
Urolithiasis in dogs V: Regional comparisons of breed, age, sex, anatomic location, and mineral type of calculus
Authors: Franti Charles E. , Ling Gerald V. , Ruby Annette L. , Johnson Deedra L.
Published: January 2024

Objective

To determine extent and nature of regional differences in distribution of canine urinary calculi.

Sample population

13,552 calculus specimens: 7,056 (52.1%) from females, 6,492 (47.9%) from males, and 4 from dogs of unrecorded sex.

Procedure

Records were used to compile information from all specimens submitted between July 1981 and December 1995. Results from mixed-breed and various breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of dogs, and anatomic location and mineral composition of specimens were analyzed and compared for 6 US geographic regions.

Results

Struvite-, apatite-, and urate-containing calculi were reported significantly most often from female dogs of the Mountain/Pacific region. Oxalate-, silica-, and brushite-containing calculi were reported significantly most often from male dogs in the New England/mid-Atlantic (NEMA) region. Cystine-containing calculi were reported most frequently from the NEMA and South Central (SC) regions. Dogs from the NEMA region were oldest in average age at diagnosis. Significant regional differences in distribution were found for several breeds. Sex distribution of renal calculi in 11 breeds of dogs (Lhasa Apso, Yorkshire Terrier, Shih Tzu, Basset Hound, Pug, Mastiff, Bichon Frise, Doberman Pinscher, Dalmatian, English Bulldog, and Pekingese) reported to be at high risk of renal lithiasis differed among the 6 geographic regions. Renal and ureteral calculi were reported significantly most often from dogs in the South Atlantic region, and bladder and urethral calculi were reported most often from dogs in the SC region.

Conclusions

Wide regional differences exist in distribution of stone-forming dogs by sex, average age at diagnosis, breed, and minerals contained within and anatomic location of calculi. (Am J Vet Res 1999;60:29–42)
Effect of a conjugate of polymyxin B-dextran 70 in horses with experimentally induced endotoxemia
Authors: MacKay Robert J. , Clark Carol K. , Logdberg Lennart , Lake Philip
Published: January 2024

Objective

To determine the efficacy of polymyxin B-dextran 70 (PBD) for treatment of endotoxemic horses.

Animals

15 horses during study 1 and 6 horses during study 2.

Procedures

3 groups were used in study 1. Horses in groups 1 and 2 were given 30 ng of lipopolysaccharide (LPS)/kg of body weight, IV, over 60 minutes. Horses in group 3 were given saline (0.9% NaCI) solution. Beginning 15 minutes before LPS infusion and continuing for 75 minutes, horses in groups 1 and 3 were given PBD, IV. Horses in group 2 were given dextran 70. Blood samples were obtained for hemograms and determination of cytokine, lactate, and prostanoid concentrations. In study 2, horses were given ketoprofen (2.2 mg/kg) or saline solution 15 minutes before infusion of PBD. Fourteen days later, treatments were reversed, using a crossover design. Blood samples were obtained for measurement of thromboxane B2 (TXB2) concentration.

Results

For study 1, prior treatment with PBD completely blocked endotoxin-induced changes for heart and respiratory rates, rectal temperature, WBC count, and plasma tumor necrosis factor, interleukin 6, TXB2, and prostaglandin F1 concentrations. There was transient tachypnea, sweating, and increased plasma TXB2 concentration in horses given PBD (with or without LPS). Prior treatment with ketoprofen eliminated all PBD-induced signs and prevented the increase in plasma TXB2 concentration.

Conclusions

Signs of endotoxemia were prevented in horses by treatment with PBD, although its use was associated with mild adverse effects.

Clinical Relevance

When used in combination with a cyclooxygenase-inhibiting drug, PBD has potential for treatment of horses with endotoxemia. (Am J Vet Res 1999;60:68–75)