Search Results

You are looking at 1 - 10 of 14 items for

  • Author or Editor: R.D. Welch x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

SUMMARY

The effects of intra-articular administration of dimethylsulfoxide (dmso) on chemically induced synovitis in the middle carpal joint of 6 weanling horses were evaluated. Following aseptic collection of synovial fluid, the middle carpal joint of each forelimb was injected with 50 mg of Namonoiodoacetate to induce synovitis. Eight days after injection, synovial fluid was obtained and the right middle carpal joints were injected with 2 ml of 40% dmso in lactated Ringer solution. The corresponding joints of the left limb (control) were injected with 2 ml of lactated Ringer solution. Sampling and treatments were repeated on postinjection days 11 and 14, for a total of 3 treatments. Horses were visually evaluated daily for lameness and joint effusion. Synovial fluid was evaluated for color and clarity, differential and total WBC count, total protein content, and hyaluronic acid concentration. The Kaegi gait analysis system provided an objective assessment of lameness prior to inducing synovitis, again on day 7, and on day 17. At necropsy (day 17), synovial fluid, synovial membrane, and articular cartilage specimens were collected.

Joint effusion was evident 12 hours after injection of Namonoiodoacetate in all joints. Mild lameness was evident at 24 hours; however, the lameness resolved by 72 hours. Objective assessment of lameness did not reveal significant differences between treatment or control limbs. Hyaluronic acid concentrations increased significantly (P = 0.023) above baseline values in most joints over the study period. Synovial fluid wbc counts increased significantly (P = 0.002) following Na-monoiodoacetate injection and remained significantly (P = 0.002) above baseline values throughout the study. There was a significantly greater decrease (P = 0.04) in total wbc counts between the pretreatment and final sampling period in the dmso-treated joints, compared with the controls. Histologic evaluation of synovial membrane samples revealed a significantly less inflammatory response in 4 of 6 dmso-treated joints, compared with that in the controls. Histochemical staining of articular cartilage did not reveal any observable difference between treated or control specimens.

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

Summary

From 1980 to 1989, 8 cesarean sections were performed on an elective basis in 5 mares. Four mares had partially obstructed pelvic canals; 2 of these mares had previously lost foals because of dystocia. Cervical adhesions that might obstruct passage of the fetus through the pelvic canal was suspected in the fifth mare. Cesarean section was performed prior to mares entering the first stage of labor. Readiness for birth was estimated by development of the mare's mammary gland and the presence of colostrum in the udder. A ventral midline celiotomy provided excellent exposure and healed without complications in all instances. Eight viable foals were produced. One foal developed bacterial pneumonia and septicemia after surgery and died. Follow-up evaluation of the 7 foals discharged from the hospital failed to reveal complications associated with elective cesarean section.

All mares survived the procedure. Fetal membranes were retained for up to 72 hours following surgery; however, systemic complications secondary to retained placenta did not develop. Three mares were bred subsequent to elective cesarean sections, with each mare conceiving the year following surgery. Three foals were produced by 1 mare and 2 foals have been produced by another mare by elective cesarean sections.

Free access
in Journal of the American Veterinary Medical Association

Summary:

Case records of cattle admitted to 2 university veterinary hospitals during 6 years were evaluated to determine the age, breed, sex, and treatment of cattle with upward fixation of the patella. Affected cattle were compared with those from the respective hospital populations of cattle admitted during the same time.

Of 38 cattle with upward fixation of the patella, 34 were treated surgically. Follow-up evaluation was obtained from owners of 28 of the treated cattle. Surgery was successful in eliminating all clinical signs in 25 of the 28 cattle. There was an increased risk of upward fixation of the patella associated with Brahman and Brahman-type cattle, compared with non-Brahman cattle.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the effects of porcine small intestinal submucosa (SIS) implants on the healing of meniscal lesions in dogs.

Animals—16 adult Greyhounds of both sexes.

Procedure—Unilateral osteotomy was performed at time 0 to disrupt the medial collateral ligament attachment, and two (1 cranial and 1 caudal) 4-mm circular defects were created in the avascular portion of the medial meniscus. One defect was filled with an SIS graft, and the other defect remained empty (control). Three months later, the identical procedure was performed on the contralateral limb. Three months after the second surgery, dogs were euthanatized, and meniscal tissue specimens from both stifle joints were collected for gross, histologic, biomechanical, and biochemical evaluations.

Results—Regenerative tissue was evident in 4 (2 SIS-implanted and 2 control) of 16 defects examined histologically. In 3 defects, this thin bridge of tissue was composed of immature haphazardly arranged fibrous connective tissue with a relatively uniform distribution of fibroblasts. Aggregate modulus, Poisson ratio, permeability, and shear modulus were not significantly different between control and SIS-implanted defects either 3 or 6 months after surgery. Hydroxyproline content also did not differ between SIS-implanted and control defects at 3 or 6 months.

Conclusions and Clinical Relevance—Implantation of porcine SIS into experimentally induced meniscal lesions in dogs did not promote tissue regeneration. (Am J Vet Res 2002;63:427–431)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the toxic effects of a Delphinium occidentale chemotype containing N-(methylsuccinimido) anthranoyllycoctonine (MSAL)—type alkaloids and a D occidentale chemotype lacking MSAL-type alkaloids in mice and cattle.

Animals—225 male Swiss Webster mice and 11 Black Angus steers.

Procedures—4 collections of larkspur containing MSAL-type alkaloids and 4 collections of larkspur lacking MSAL-type alkaloids were used. From each collection, total alkaloid extracts (0.05 to 0.20 mL) were administered via tail-vein injection in 27 to 29 mice. Dried, finely ground plant material from 1 collection with and 1 collection without MSAL-type alkaloids (doses equivalent to 37.6 mg of total alkaloids/kg) were each administered to 8 cattle via oral gavage in a crossover experiment; 3 cattle received a single dose equivalent to 150.4 mg of total alkaloids/kg (no MSAL-type alkaloids). In mice, clinical effects were monitored; in cattle, heart rate was monitored before (baseline) and 24 hours after treatment. At the 24-hour time point, cattle were exercised as a measure of muscle weakness.

Results—In mice, mean LD50 associated with alkaloid extracts prepared from plants that did or did not contain MSAL-type alkaloids was 2.3 and 54.2 mg/kg, respectively. In cattle at 24 hours after treatment, plant material containing MSAL-type alkaloids significantly increased heart rate from baseline and was associated with exercise-induced collapse; plant material lacking MSAL-type alkaloids had no similar effects.

Conclusions and Clinical Relevance—Taxonomic classification of D occidentale alone was not a good indicator of the toxic risk to grazing cattle.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the toxicokinetics of N-(methylsuccinimido)anthranoyllycoctonine–type low larkspur alkaloids in beef cattle.

Animals—5 Black Angus steers and 35 Swiss Webster mice.

Procedures—Low larkspur (Delphinium andersonii) was collected, dried, ground, and administered to 5 steers via oral gavage to provide a dose of 12 mg of N-(methylsuccinimido)-anthranoyllycoctonine alkaloids/kg. Steers were housed in metabolism crates for 96 hours following larkspur administration; heart rate was monitored continuously, and blood samples were collected periodically for analysis of serum concentrations of 16-deacetylgeyerline, methyllycaconitine, geyerline, and nudicauline and assessment of kinetic parameters. The LD50 of a total alkaloid extract from D andersonii was determined in Swiss Webster mice.

Results—The alkaloids were quickly absorbed, with a maximum serum concentration achieved within 18 hours after administration. Geyerline and nudicauline coeluted as 1 peak and were considered together for toxicokinetic analysis. Mean ± SD elimination half-life was 18.4 ± 4.4 hours, 15.6 ± 1.5 hours, and 16.5 ± 5.1 hours for 16-deacetylgeyerline, methyllycaconitine, and geyerline and nudicauline, respectively. There were significant differences in maximum serum concentration, amount absorbed, and distribution half-life among the 4 alkaloids. The mouse LD50 was 9.8 mg/kg.

Conclusions and Clinical Relevance—Results suggested that clinical poisoning was likely to be most severe approximately 18 hours after exposure. Cattle should be closely monitored for at least 36 hours after initial exposure. Additionally, a withdrawal time of approximately 7 days would be required to clear > 99% of the toxic alkaloids from the serum of cattle that have ingested low larkspur.

Full access
in American Journal of Veterinary Research