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Abstract

Objective—To determine the dimensions and volume of thyroid tissue in clinically normal cats by use of computed tomography.

Animals—8 cats.

Procedure—Helical computed tomography images (2-mm collimation) were acquired from the cranial aspect of the second cervical vertebra through the caudal aspect of the fourth cervical vertebra. Data were acquired before contrast medium administration (n = 7 cats) and immediately after contrast medium enhancement (1 cat). Length, width, and height measurements of each thyroid lobe were made by use of transverse, dorsal, and sagittal plane images. Thyroid lobe volume was estimated by use of 3 methods.

Results—All thyroid lobes were histologically normal. Mean dimensions for a thyroid lobe were 16.5 × 2.00 × 4.31 mm (length × width × height) using only data from transverse images. Mean thyroid lobar volume was 113.75 mm3 using the sum of areas method. Mean total volume of thyroid tissue was 215.25 mm3 using the sum of areas method.

Conclusions and Clinical Relevance—Results may be useful for computed tomography evaluation of abnormal thyroid glands in cats, which warrants investigation.

Full access
in American Journal of Veterinary Research

SUMMARY

The degree and type of tissue reactivity and the absorption of a new suture material was determined by implantation within rat gluteal muscles. Amount and type of tissue inflammatory reaction was compared among the new suture material, polypropylene, and coated polyamide.

Histologic evaluation of the tissues in which sutures were implanted indicated that the new suture material, polypropylene, and coated polyamide had similar amounts and types of reaction at 30 days or less after implantation, but differed after 30 days. The new suture material and polypropylene had an inflammatory reaction zone measuring less than 25% of the high-power field after 60 days, but the coated polyamide still induced reaction greater than 45% of the field at 90 days. At 60 and 90 days after implantation, the new suture material and polypropylene induced a mature fibrous reaction; the reaction to coated polyamide was either immature fibrous or granulomatous, depending on whether there was rupture of the suture coat. There was no observable absorption of the new suture material at 90 days.

This study indicated that the new suture material is nonabsorbable and is minimally reactive in rat muscle. The tissue reactions induced by this suture material are similar to those of polypropylene and significantly less than those induced by coated polyamide after 30 days following implantation.

Free access
in American Journal of Veterinary Research

Summary

A standardized cortical defect was created on the caudal cortex of the proximal portion of each ulna in 5 adult mixed-breed dogs. One gram of autogenous cancellous bone graft (acbg) was obtained from the greater tubercle of the ipsilateral humerus. The cortical defect in the ulna of 1 limb was filled with 1 g of acbg that had been compressed with 2-MPa pressure for 30 seconds. One gram of noncompressed acbg was placed into the contralateral ulnar cortical defect. The compressed and noncompressed acbg recipient sites were radiographed at weekly intervals. Dogs were euthanatized 8 weeks after surgery, and the acbg recipient sites were harvested for histomor-phometric analysis. Optical densitometry was performed on all radiographs. There was no significant difference between compressed and noncompressed acbg with optical densitometry or histomorphometric analysis for total bone area. We concluded that there was no difference in osteogenic capability between compressed and noncompressed acbg of equal mass.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effects of anti-inflammatory drugs on lipopolysaccharide (LPS)-challenged and -unchallenged equine synovial membrane in terms of production of prostaglandin E2 (PGE2) and hyaluronan, viability, and histomorphologic characteristics.

Sample Population—Synovial membranes were collected from the carpal, tarsocrural, and femoropatellar joints of 6 adult horses.

Procedure—Synovial membranes from each horse were minced and pooled and explants were treated with one of the following: no drug (control), drug, LPS alone, or LPS and drug. Treatment drugs were phenylbutazone (PBZ), flunixin meglumine (FNX), ketoprofen (KET), carprofen (CRP), meloxicam (MEL), low-concentration methylprednisolone (METH), highconcentration METH, dimethyl sulfoxide (DMSO), or an experimental COX-2 inhibitor (dissolved in DMSO). Following 48 hours of culture, medium was assayed for PGE2 and hyaluronan concentration. Synovial explants were assessed for viability and histomorphologic characteristics.

Results—For the LPS-challenged explants, PBZ, FNX, KTP, CRP, MEL, and low-concentration METH suppressed PGE2 production, compared with LPS challenge alone. Only MEL suppressed PGE2 production from LPS-challenged explants, compared with unchallenged explants. Synovial explants maintained > 90% viability and there was no significant difference in viability or hyaluronan production among explants. Histomorphologic scores were significantly decreased for explants treated with low-concentration METH or DMSO.

Conclusions and Clinical Relevance—PBZ, FNX, KTP, CRP, MEL, and low-concentration METH suppressed PGE2 production in LPS-challenged explants. Meloxicam appeared to have more selective suppression of COX-2 activity. Histomorphologic scores suggest detrimental effects of METH, DMSO, and the experimental COX-2 inhibitor. Commonly used nonsteroidal anti-inflammatory drugs suppress induced synovial membrane PGE2 production without detrimental effects on synovial membrane viability and function. ( Am J Vet Res 2001;62:54–60)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of pretreatment with α-linolenic acid, an omega-3 polyunsaturated fatty acid, on equine synovial explants challenged with lipopolysaccharide (LPS).

Animals—8 mature mixed-breed horses (4 mares and 4 geldings).

Procedure—Synovial explants were assigned to receive 1 of 7 concentrations of α-linolenic acid, ranging from 0 to 300 µg/mL. At each concentration, half of the explants were controls and half were challenged with 0.003 µg of LPS as a model of synovial inflammation. Cell inflammatory response was evaluated by measurement of prostaglandin E2 production via an ELISA. Synovial cell viability, function, histomorphologic characteristics, and cell membrane composition were evaluated by use of trypan blue dye exclusion, hexuronic acid assay for hyaluronic acid, objective microscopic scoring, and high-performance liquid chromatography, respectively.

Results—Challenge with LPS significantly increased production of prostaglandin E2 and decreased production of hyaluronic acid. Treatment with α-linolenic acid at the highest dose inhibited prostaglandin E2 production. Cell viability and histomorphologic characteristics were not altered by treatment with α-linolenic acid or LPS challenge. Treatment with α-linolenic acid increased the percentage of this fatty acid in the explant cell membranes.

Conclusions and Clinical Relevance—Results suggest that investigation of α-linolenic acid as an anti-inflammatory medication for equine synovitis is warranted. (Am J Vet Res 2005;66:1503–1508)

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective

To quantitate nitric oxide synthase (NOS) activity in healthy and interleukin 1β (IL-1β)-exposed equine synovial membrane.

Animals

6 healthy horses, 2 to 8 years old.

Procedure

Recombinant human IL-1β (0.35 ng/kg of body weight) was injected intra-articularly into 1 metacarpophalangeal joint of each horse. The contralateral joint served as an unexposed control. All horses were euthanatized 6 hours after injection of IL-1β, and synovial membrane specimens were assayed for NOS activity by measuring conversion of arginine to citrulline. Severity of inflammation was semiquantitated by analysis of synovial fluids and histologic examination of synovial membrane.

Results

Equine synovial membrane had minimal NOS activity. A significant difference was not detected in NOS activity between control and IL-1β-exposed specimens. Histologic examination revealed a neutrophilic infiltrate in synovial membrane exposed to IL-1β. Synovial fluid from IL-1β-exposed joints had a moderate inflammatory response and significantly greater concentrations of IL-1β and interleukin-6 than fluid from healthy joints.

Conclusion

Healthy equine synovial membrane had low NOS activity that was not affected by exposure to IL-1β. (Am J Vet Res 1999;60:714-716)

Free access
in American Journal of Veterinary Research

SUMMARY

We compared the frequency and severity of osteochondrosis lesions in young Thoroughbred horses with cervical stenotic myelopathy (csm) vs that in clinically normal Thoroughbreds of the same age. All lesions of the cervical vertebrae and appendicular skeleton were classified histologically as osteochondrosis or nonosteochondrosis and were measured for severity. Minimal sagittal diameter was significantly smaller in horses with csm from C2 through C6; no difference was detected at C7. Severity of cervical vertebral osteochondrosis was greater in the horses with csm, however frequency was not different. Frequency and severity of nonosteochondrosis lesions were not different in cervical vertebrae or appendicular skeleton. Frequency and severity of appendicular skeleton osteochondrosis lesions were both greater in horses with csm. Osteochondrosis and nonosteochondrosis lesions were more severe on facets at sites of compression than on facets at noncompressed sites in horses with csm. However, compression was also observed at sites with no articular facet lesions. The association of widespread osteochondrosis and spinal canal narrowing with csm suggests csm may represent a systemic failure in the development or maturation of cartilage and bone.

Free access
in American Journal of Veterinary Research

SUMMARY

Pleural effusion was induced in 12 dogs by ligation of the cranial vena cava. Pleurodesis was attempted by injecting a solution of tetracycline hydrochloride into the pleural space of 8 dogs (4 dogs, 25 mg/kg of body weight; 4 dogs, 50 mg/kg) via bilateral thoracostomy tubes. In both groups, tetracycline was diluted in 40 ml of normal saline solution and 10 ml of 1% lidocaine before injection. Half of the solution (25 ml) was instilled in each hemithorax. Four control dogs were treated in the same manner with a solution of normal saline and lidocaine. Daily pleural fluid production was measured after the attempted pleurodesis. Thirty days after administration of the solution, each dog was euthanatized and necropsied. Surface area of pleural adhesions was measured. Tissues from regions of pleural adhesions and areas of parietal and visceral pleura not involved in adhesions were analyzed histologically.

Formation of pleural fluid stopped in all but 1 control dog within 48 hours after injection of solution. This dog effused throughout the study. The resolution of effusion was not significantly (P < 0.05) different between the tetracycline-treated dogs and the control group. Although diffuse pleural adhesions were not induced in any of tbe dogs, significantly (P < 0.0027) more surface area of lung was adhered in dogs treated with the higher dose of tetracycline.

Free access
in American Journal of Veterinary Research