Tarsocrural joint polymyxin B concentrations achieved following intravenous regional limb perfusion of the drug via a saphenous vein to healthy standing horses.

OBJECTIVE: To determine whether therapeutic concentrations (> 0.5 to 1.0 µg/mL) of polymyxin B (PB) were achieved in the tarsocrural joint of horses when the drug was administered by IV regional limb perfusion (IV-RLP) via a saphenous vein at doses of 25, 50, and 300 mg and to describe any adverse systemic or local effects associated with such administration. ANIMALS: 9 healthy adult horses. PROCEDURES: In the first of 2 experiments, 6 horses each received 25 and 50 mg of PB by IV-RLP via a saphenous vein with at least 2 weeks between treatments. For each treatment, a tourniquet was placed at the midmetatarsus and another was placed midway between the stifle joint and tarsus. Both tourniquets were removed 30 minutes after the assigned dose was administered. Blood and tarsocrural joint fluid samples were collected for determination of PB concentration before and at predetermined times after drug administration. In experiment 2, 4 horses were administered 300 mg of PB by IV-RLP in 1 randomly selected pelvic limb in a manner identical to that used in experiment 1. RESULTS: For all 3 doses, the mean synovial fluid PB concentration was > 10 times the therapeutic concentration and below the level of quantification at 30 and 1,440 minutes after drug administration, respectively. No adverse systemic or local effects were observed following PB administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that IV-RLP of PB might be a viable alternative for treatment of horses with synovial infections caused by gram-negative bacteria.

Evaluation of tyrosinase expression in canine and equine melanocytic tumors.

OBJECTIVE: To determine the tissue-restricted expression pattern of tyrosinase mRNA in canine and equine melanocytic tumors and relative tyrosinase and major histocompatibility complex (MHC) I mRNA expression in variants of melanocytic tumors. SAMPLE: 39 canine and 8 equine tumor samples and 10 canine and 6 equine normal tissue samples. PROCEDURES: RNA was isolated from formalin-fixed, paraffin-embedded tissues. Real-time PCR assays were designed to amplify canine and equine tyrosinase, S18 ribosomal RNA, and major histocompatibility complex I transcripts. Relative expression was determined by use of S18 as a reference and comparison with pigmented and nonpigmented normal tissues. RESULTS: High tyrosinase expression was found in all melanocytic tumors, compared with normal tissues, and expression had no correlation with presence or absence of tumor pigmentation. No significant difference in tyrosinase expression was found among histologic variants of melanocytic tumors. No correlation was found between MHC I and tyrosinase expression or tissue histologic classification. CONCLUSIONS AND CLINICAL RELEVANCE: In the present study, the methods used were highly sensitive and specific for detection of tyrosinase expression in equine and canine tumors, and overexpression of this transcript in melanomas was detected. This suggested that a DNA vaccine developed for use in dogs with melanoma that targets tyrosinase may be considered for use in other affected species, such as horses.

Clinical evaluation of a closed, one-stage, stapled, functional, end-to-end jejuno-ileal anastomosis in 5 horses.

This study describes the outcome and complications in horses that had a closed, one-stage, stapled, functional, end-to-end (COSFE) jejuno-ileal anastomosis (JIA) following resection of compromised small intestine. Medical records were reviewed to identify all horses that had a COSFE JIA performed during exploratory laparotomy and to determine post-operative complications and final outcome. All 5 horses that were identified had successful COSFE JIA with resection of various amounts of distal jejunum and proximal ileum. Post-operative ileus occurred in 1 of the 5 horses. All horses survived at least 1 year after surgery. The survival times and incidence of post-operative ileus compared favorably with published results for other types of small intestinal resection and anastomoses. A COSFE JIA is a viable surgical procedure to correct lesions of the distal jejunum and proximal ileum.This study describes the outcome and complications in horses that had a closed, one-stage, stapled, functional, end-to-end (COSFE) jejuno-ileal anastomosis (JIA) following resection of compromised small intestine. Medical records were reviewed to identify all horses that had a COSFE JIA performed during exploratory laparotomy and to determine post-operative complications and final outcome. All 5 horses that were identified had successful COSFE JIA with resection of various amounts of distal jejunum and proximal ileum. Post-operative ileus occurred in 1 of the 5 horses. All horses survived at least 1 year after surgery. The survival times and incidence of post-operative ileus compared favorably with published results for other types of small intestinal resection and anastomoses. A COSFE JIA is a viable surgical procedure to correct lesions of the distal jejunum and proximal ileum.

RésuméÉvaluation clinique d'une anastomose jéjuno-iléale fermée, en un temps, agrafée, fonctionnelle et termino-terminale chez 5 chevaux. Cette étude décrit le résultat et les complications d'une anastomose jéjuno-iléale (AJI) fermée, en un temps, agrafée, fonctionnelle et termino-terminale (FTAFTT) chez des chevaux après la résection d'un petit intestin compromis. Les dossiers médicaux ont été examinés pour identifier tous les chevaux qui avaient subi une AJI FTAFTT durant une laparotomie exploratoire et déterminer les complications postopératoires et le résultat final. Les 5 chevaux qui ont été identifiés ont tous subi une AJI FTAFTT réussie avec résection de diverses quantités du jéjunum distal et de l'iléon proximal. Une occlusion intestinale postopératoire s'est produite chez 1 des 5 chevaux. Tous les chevaux ont survécu au moins 1 an après la chirurgie. Le temps de survie et l'incidence d'une occlusion intestinale postopératoire ont présenté une comparaison favorable avec les résultats publiés pour d'autres types de résection du petit intestin et d'anastomoses. Une AJI FTAFTT est une intervention chirurgicale viable pour corriger les lésions du jéjunum distal et de l'iléon proximal.(Traduit par Isabelle Vallières).

Macroscopic anatomy of the reproductive tract of the reproductively quiescent female emu (Dromaius novaehollandiae).

Three reproductively quiescent female emus (Dromaius novaehollandiae) were embalmed with 10% formalin solution. The reproductive tract was dissected and described. The reproductive tract consists of an ovary and oviduct situated on the left side of the abdominal cavity. The left ovary is dark brown to black in colour with follicles covering the ventral surface. The ovary is located medial to the spleen and closely associated with the ventral surface of the cranial and middle lobes of the left kidney. The oviduct is a relatively straight tube that extends from the level of the cranial extent of the left ilium to the caudal border of the left pubic bone. The oviduct is grossly divided into the infundibulum, magnum, isthmus, uterus and vagina using variations in the mucosal fold pattern.

A new approach for perineural injection of the lateral palmar nerve in the horse.

OBJECTIVE: To evaluate the accuracy of a new technique for perineural injection of the lateral palmar nerve and to determine frequency of inadvertent injection into the carpal synovial sheath with this technique. STUDY DESIGN: Prospective experimental study. ANIMALS: Thirty equine cadaver forelimbs. METHODS: Each of 3 clinicians injected 0.5 mL of a 1% aqueous solution of new methylene blue as a marker at the medial aspect of the accessory carpal bone of 10 limbs. Immediately after each injection, the lateral palmar nerve was identified by dissection of and inspected for proximity of dye, and the carpal synovial sheath was inspected for the presence of dye. RESULTS: New methylene blue solution was observed to surround the nerve (29 limbs) or to lie within 2 mm of it (1 limb). Dye was not found in the carpal synovial sheath of any specimen. CONCLUSIONS: Using this technique, perineural injection of the lateral palmar nerve can be consistently achieved, and the carpal synovial sheath is unlikely to be penetrated by the needle during the procedure. CLINICAL RELEVANCE: The technique described provides an accurate and simple method for perineural injection of the lateral palmar nerve proximal to the origin of its deep branch. This technique can be used to anesthetize the lateral palmar nerve for diagnosis of pain originating in the palmaroproximal aspect of the metacarpus without risk of inadvertently desensitizing structures within the carpal synovial sheath.

A comparison of the mechanical strength of two stapled anastomosis techniques for equine small intestine.

OBJECTIVE: To compare bursting strength, time of construction, and cost of a closed one-stage, stapled functional end-to-end jejunojejunostomy (FEE) with a stapled side-to-side jejunojejunostomy (STS). STUDY DESIGN: Experimental, randomized block design. ANIMALS: Seven adult horses without gastrointestinal disease. METHODS: The jejunum was isolated, and three FEE, three STS, and three control segments were created in each horse using a randomized block design. Anastomosis time was recorded. The intraluminal pressure at failure and mode of failure were recorded. Length at failure was measured on digitized images. Bursting pressure (BP), bursting wall tension (BWT), anastomosis time, and cost were compared. RESULTS: Control jejunal segments were stronger (P < or = .0001) in bursting strength and bursting wall tension (P < or = .0001) than either anastomosis type; no difference was found between anastomosis types for either variable. Functional end-to-end jejunojejunostomy was significantly quicker and less costly than STS (P < or = .0001). CONCLUSIONS: Mechanically there were no significant differences between the FEE and STS techniques. The FEE technique maintained the physiologic direction of peristalsis of the segments, required less tissue manipulation, and was faster and more economical to create. CLINICAL RELEVANCE: The FEE is a clinically viable technique.