An engineered bivalent neuregulin protects against doxorubicin-induced cardiotoxicity with reduced proneoplastic potential

BACKGROUND

Doxorubicin (DOXO) is an effective anthracycline chemotherapeutic, but its use is limited by cumulative dose-dependent cardiotoxicity. Neuregulin-1β is an ErbB receptor family ligand that is effective against DOXO-induced cardiomyopathy in experimental models but is also proneoplastic. We previously showed that an engineered bivalent neuregulin-1β (NN) has reduced proneoplastic potential in comparison with the epidermal growth factor-like domain of neuregulin-1β (NRG), an effect mediated by receptor biasing toward ErbB3 homotypic interactions uncommonly formed by native neuregulin-1β. Here, we hypothesized that a newly formulated, covalent NN would be cardioprotective with reduced proneoplastic effects in comparison with NRG.

METHODS AND RESULTS

NN was expressed as a maltose-binding protein fusion in Escherichia coli. As established previously, NN stimulated antineoplastic or cytostatic signaling and phenotype in cancer cells, whereas NRG stimulated proneoplastic signaling and phenotype. In neonatal rat cardiomyocytes, NN and NRG induced similar downstream signaling. NN, like NRG, attenuated the double-stranded DNA breaks associated with DOXO exposure in neonatal rat cardiomyocytes and human cardiomyocytes derived from induced pluripotent stem cells. NN treatment significantly attenuated DOXO-induced decrease in fractional shortening as measured by blinded echocardiography in mice in a chronic cardiomyopathy model (57.7±0.6% versus 50.9±2.6%, P=0.004), whereas native NRG had no significant effect (49.4±3.7% versus 50.9±2.6%, P=0.813).

CONCLUSIONS

NN is a cardioprotective agent that promotes cardiomyocyte survival and improves cardiac function in DOXO-induced cardiotoxicity. Given the reduced proneoplastic potential of NN versus NRG, NN has translational potential for cardioprotection in patients with cancer receiving anthracyclines.

Ss-bCNGa: a unique member of the bacterial cyclic nucleotide gated (bCNG) channel family that gates in response to mechanical tension

Bacterial cyclic nucleotide gated (bCNG) channels are generally a nonmechanosensitive subset of the mechanosensitive channel of small conductance (MscS) superfamily. bCNG channels are composed of an MscS channel domain, a linking domain, and a cyclic nucleotide binding domain. Among bCNG channels, the channel domain of Ss-bCNGa, a bCNG channel from Synechocystis sp. PCC 6803, is most identical to Escherichia coli (Ec) MscS. This channel also exhibits limited mechanosensation in response to osmotic downshock assays, making it the only known full-length bCNG channel to respond to hypoosmotic stress. Here, we compare and contrast the ability of Ss-bCNGa to gate in response to mechanical tension with Se-bCNG, a nonmechanosensitive bCNG channel, and Ec-MscS, a prototypical mechanosensitive channel. Compared with Ec-MscS, Ss-bCNGa only exhibits limited mechanosensation, which is most likely a result of the inability of Ss-bCNGa to form the strong lipid contacts needed for significant function. Unlike Ec-MscS, Ss-bCNGa displays a mechanical response that increases with protein expression level, which may result from channel clustering driven by interchannel cation-π interactions.

Engineered bivalent ligands to bias ErbB receptor-mediated signaling and phenotypes

The ErbB receptor family is dysregulated in many cancers, and its therapeutic manipulation by targeted antibodies and kinase inhibitors has resulted in effective chemotherapies. However, many malignancies remain refractory to current interventions. We describe a new approach that directs ErbB receptor interactions, resulting in biased signaling and phenotypes. Due to known receptor-ligand affinities and the necessity of ErbB receptors to dimerize to signal, bivalent ligands, formed by the synthetic linkage of two neuregulin-1β (NRG) moieties, two epidermal growth factor (EGF) moieties, or an EGF and a NRG moiety, can potentially drive homotypic receptor interactions and diminish formation of HER2-containing heterodimers, which are implicated in many malignancies and are a prevalent outcome of stimulation by native, monovalent EGF, or NRG. We demonstrate the therapeutic potential of this approach by showing that bivalent NRG (NN) can bias signaling in HER3-expressing cancer cells, resulting in some cases in decreased migration, inhibited proliferation, and increased apoptosis, whereas native NRG stimulation increased the malignant potential of the same cells. Hence, this new approach may have therapeutic relevance in ovarian, breast, lung, and other cancers in which HER3 has been implicated.

External coaptation for the treatment of long bone fractures in cattle: a retrospective study of 35 cases (1996-2001)

The objective of this retrospective study was to report the history, signalment, frequency, types, complications, and long-term outcome of long bone fractures in cattle treated using external coaptation techniques. The sex, age, breed, history, physical examination findings, and radiographic findings were recorded. Of 35 cases with long bone fractures treated using external coaptation, 31 were discharged alive. The mean hospitalization time for these cattle was 2 days. Six to 12 months after treatment, 26 (84%) cases were considered satisfactorily healed. It was concluded that cattle with long bone fractures could be treated successfully using external coaptation with minimal effect on productivity.

Neodymium:yttrium aluminum garnet laser ventriculocordectomy in standing horses

OBJECTIVE

To develop a technique for neodymium:yttrium-aluminum-garnet (Nd:YAG) laser ventriculocordectomy in standing horses and document healing in horses undergoing laser ventriculocordectomy.

ANIMALS

6 horses between 2 and 32 years old.

PROCEDURE

Under endoscopic guidance, the left laryngeal ventricle was everted with grasping forceps and excised with an Nd:YAG laser, using 60 watts of power in a noncontact fashion (6,403 to 9,197 Joules). Following removal of the ventricle, the vocal cord was photoablated. Horses were examined endoscopically 2, 7, 14, 21, 30, and 47 days after ventriculocordectomy, and 1 horse was euthanatized on each of these days. At necropsy, the larynx was removed intact and examined grossly. Samples were collected for histologic examination of the ventriculocordectomy site.

RESULTS

Endoscopic examination revealed granulation tissue by day 7, the start of epithelialization by day 21, and healing by day 47. At necropsy, 4 horses were found to have a small amount of ventricular mucosa remaining dorsally and 1 additional horse was found to have a mucocele. Granulation tissue was identified grossly and histologically in the horses euthanatized between 7 and 30 days after surgery. Incipient reepithelialization was evident histologically on day 14, and complete reepithelialization of the surgery site was evident by day 47.

CONCLUSION AND CLINICAL RELEVANCE

Results suggest that ventriculocordectomy can safely be performed with an Nd:YAG laser in standing horses.

Fistulation of the auditory tube diverticulum (guttural pouch) with a neodymium:yttrium-aluminum-garnet laser for treatment of chronic empyema in two horses

Two horses with chronic empyema of the auditory tube diverticulum (guttural pouch) were refractory to medical treatment; empyema was bilateral in 1 horse and unilateral in the other. Both horses were treated by fistulation of the cartilage of the pharyngeal orifice by use of a neodymium:yttrium-aluminum-garnet laser in a noncontact manner. To maintain patency of the fistulae, indwelling catheters were placed into the openings created by the laser. For both horses, long-term follow-up did not reveal complications, and both owners were satisfied with results of the procedure. The authors recommend this procedure for horses that are unresponsive to medical treatment for chronic guttural pouch empyema.

Treatment of supraspinous bursitis by use of debridement in standing horses: 10 cases (1968-1999)

OBJECTIVE

To evaluate efficacy of debridement for treatment of supraspinous bursitis in horses and to evaluate the outcome.

DESIGN

Retrospective study.

ANIMALS

10 horses with clinical signs of supraspinous bursitis.

PROCEDURE

Medical records were reviewed for signalment, anamnesis, results of physical and radiographic examination, microbial culture results of supraspinous bursa tissue or exudate, Brucella abortus titers, type of antimicrobial and anti-inflammatory therapies, surgical technique, complications of the surgical procedure, and findings on histologic examination of excised nuchal ligament and bursal tissue. Telephone follow-up with owners, trainers, or referring veterinarians was performed.

RESULTS

The described surgical technique was effective in resolving drainage from the supraspinous bursal region in 5 of 6 horses available for long-term follow-up. The most common complication following surgery was the development of purulent wound drainage. Two horses required multiple surgeries to resolve clinical signs of supraspinous bursitis. The most common organism isolated from the supraspinous bursa was beta-hemolytic Streptococcus spp. All horses were discharged from the hospital and long-term follow-up was available for 6 horses. All 6 horses could be used for their intended use.

CONCLUSIONS AND CLINICAL RELEVANCE

Debridement in standing horses is an effective method of resolving clinical signs of supraspinous bursitis.

Diagnosis of sporotrichosis in a donkey using direct fluorescein-labeled antibody testing

A 4-year-old female donkey residing in an open field in Indiana was admitted for evaluation of facial lesions of 2 years duration. Cytologic and histologic examination of exudate and tissue from the lesions revealed a pyogranulomatous inflammatory reaction with numerous yeasts. Sporothrix schenckii was suspected to be the infectious agent; however, multiple culture attempts did not provide positive identification of the organism. Serologic examination supported infection with S. schenckii. A specific direct immunofluorescent antibody test performed on paraffin-embedded tissue sections confirmed the organism as S. schenckii. Clinical signs resolved after appropriate iodide therapy.

High intraosseous pressure as a cause of lameness in a horse with a degloving injury of the metatarsus

A 6-year-old Paint mare undergoing treatment for a degloving injury of the right metatarsus developed a non-weight-bearing lameness 19 days after admission. Diagnostic nerve blocks localized the source of pain to the area between the tarsus and the metatarsophalangeal joint. Radiography of the metatarsus and metatarsophalangeal joint, arthrocentesis of the metatarsophalangeal joint, and ultrasonography of the flexor tendons, flexor tendon sheath, and suspensory ligament failed to identify the cause of the lameness. The horse was anesthetized and intraosseous pressure was measured in the left and right third metatarsal bones, using a self-tapping cannulated screw attached to a pressure transducer. Pressure in the affected limb (46 mm Hg) was 3.5 times as high as pressure in the unaffected limb (13 mm Hg). The day after pressures were measured and fenestration was performed, signs of lameness were substantially improved. High intraosseous pressure in the affected limb was most likely secondary to edema, inflammation, and partial venous thrombosis, in combination with bone neovascularization, that impaired intraosseous venous drainage from the medullary cavity. Fenestration of the affected bone relieved the excessive pressure and allowed for resolution of pain.

Surgical correction of polydactyly in a camel (Camelus dromedarius)

A 2-mo-old, 90-kg, intact male camel (Camelus dromedarius) was admitted for surgical removal of a supernumerary digit associated with the medial aspect of the right carpus and metacarpus. Radiographic views of the carpus and metacarpus revealed the supernumerary digit articulating with the middle carpal joint via an extra carpal bone. The supernumerary digit consisted of three bones. Surgical removal of the supernumerary digit was recommended to restore normal limb conformation, limit the possibility of future lameness, and improve the cosmetic appearance of the limb. Complete surgical removal of the digit was performed by disarticulating the extra carpal bone from its attachments to the second and radial carpal bones. One year after surgery, the leg appeared grossly normal and the camel showed no sign of lameness.

Management of rupture of the gastrocnemius and superficial digital flexor muscles with a modified Thomas splint-cast combination in a horse

A 6-month-old warmblood filly had traumatic rupture in the gastrocnemius and superficial digital flexor muscles of the left hind limb. A modified Thomas splint-cast combination, which was custom fitted to the limb, was placed to prevent further disruption of the caudal reciprocal apparatus. The external coaptation device was removed after 21 days. The horse developed lesions consistent with osteochondrosis of the femoropatellar articulation within 8 weeks of the initial injury. Examination of the horse 6 months after injury revealed fibrous healing of the muscles and restoration of caudal reciprocal apparatus function. There was no obvious difference in the external appearance of the hind limbs.

Complete fractures of the third metacarpal or metatarsal bone in horses: 25 cases (1980-1996)

OBJECTIVES

To compare treatments of complete fractures of the third metacarpal (MC) or metatarsal (MT) bone in horses and to identify factors that could impact prognosis.

DESIGN

Retrospective case series.

ANIMALS

25 horses with fractures of the third MC or MT bone that were treated by use of internal fixation, external coaptation, or both.

PROCEDURE

Medical records from the Veterinary Medical Data Base of horses treated for fractures of third MC or MT bone at Texas A&M University from 1980 to 1994 and Purdue University from 1980 to 1996 were reviewed. Information on signalment, results of physical and radiographic examinations, treatment, and outcome were obtained. For horses that had radiographic evidence of healing, long-term follow-up information was obtained by telephone contact with owners or referring veterinarians.

RESULTS

Age, sex, weight, and limb affected were not related to outcome; however, affected horses were younger than the general hospital populations. Seventeen horses had open fractures at referral. Infection was the most common complication after surgery, with open fractures more likely to become infected. Nonunion in an infected fracture was the most common reason for postoperative failure (7 horses). Long-term follow-up was available for 16 horses; 11 of these had no complications related to surgical repair.

CLINICAL IMPLICATIONS

Fractures of the MC or MT bone are not always associated with a poor prognosis in horses. Proper case selection, rigid fracture stabilization, and efforts to prevent or treat infection will improve success rate.

Cobalt 60 radiotherapy for treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses in three horses

Three adult horses underwent aggressive treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses, using course-fractionated cobalt 60 radiotherapy. Squamous cell carcinoma of the nasal cavity and paranasal sinuses is not commonly diagnosed in horses. Historically, horses with this type of neoplasm have not been treated or have undergone some form of surgery. The prognosis for long-term survival or cure has been poor. Long-term results of cobalt 60 radiotherapy were good to excellent and exceeded those usually reported for horses treated surgically. On the basis of these results, use of radiotherapy for these neoplasms is recommended.

Primary hyperparathyroidism with osteodystrophia fibrosa of the facial bones in a pony

A 17-year-old pony mare was admitted for evaluation of progressive enlargement of the facial bones during the preceding 9 months. Laboratory testing revealed that the pony had hypercalcemia, hypophosphatemia, high urinary fractional excretion of phosphorus, and high serum concentration of intact parathyroid hormone (185.1 pmol/L; reference range, 0.25 to 2.0 pmol/L). On the basis of these findings, a diagnosis of primary hyperparathyroidism was made by ruling out nutritional secondary hyperparathyroidism, chronic renal disease, and pseudohyperparathyroidism resulting from neoplasia. Although primary hyperparathyroidism is best treated by surgical removal of the affected parathyroid gland, the owners declined surgical exploration of the neck in this pony. Because of the poor prognosis, the pony was euthanatized. A functional lesion of the parathyroid tissue was not located on necropsy or histologic examination. Difficulty localizing and grossly identifying parathyroid tissue in horses complicates definitive diagnosis and treatment of primary hyperparathyroidism.

Laryngoplasty with or without ventriculectomy for treatment of left laryngeal hemiplegia in 230 racehorses

OBJECTIVE

The purpose of this study was to examine the influence of laryngoplasty on racing performance and to determine if any of the following variables had a significant effect on outcome: breed (Thoroughbred v Standardbred), endoscopic grade of laryngeal function, ventriculectomy versus no ventriculectomy, type of prosthetic suture used, and number of prostheses placed.

STUDY DESIGN

Retrospective study of laryngoplasty with or without ventriculectomy for treatment of left laryngeal hemiplegia in racehorses between 1986 and 1993.

ANIMALS OR SAMPLE POPULATION

230 horses (174 Thoroughbreds, 56 Standardbreds).

METHODS

The medical records of racehorses or horses intended for racing were reviewed. Signalment, admitting complaints, physical examination findings, resting endoscopic grade of laryngeal function, type of prosthetic suture material used, number of prosthetic sutures placed, presence or absence of ventriculectomy, and postoperative complications were recorded.

RESULTS

Upper respiratory tract noise and exercise intolerance were the most common presenting complaints. Two horses had a laryngeal grade of 2, 109 horses a laryngeal grade of 3, and 119 horses a laryngeal grade of 4. Two double-strand braided polyester sutures were used in 147 horses, a single double-strand polyester suture was used in 49 horses, and a single double-strand nylon suture was used in 34 horses. Ventriculectomy was performed on 186 horses. The most common complication recognized during hospitalization was coughing in 50 horses. Telephone follow-up was obtained for 176 horses. For 168 horses, respiratory noise after surgery was decreased in 126 horses, the same in 28, and increased in 14. After hospital discharge, coughing occurred in 43 of 166 horses, and a nasal discharge occurred in 26 horses. Postoperative racing performance for 167 horses was subjectively evaluated by respondents as being improved in 69% of the horses. Overall owner satisfaction with the outcome after surgery was 81%. Of 230 horses, 178 raced at least one time after surgery. Overall, 117 horses raced three or more times before and after surgery, and 65 of these horses had improved performance index scores. None of the variables of surgical interest affected performance index scores.

CONCLUSIONS AND CLINICAL RELEVANCE

Laryngoplasty with or without ventriculectomy allowed 77% of the horses to race at least one time after surgery, improved racing performance in 56% of the horses that completed three races before and after surgery, and improved subjectively evaluated racing performance in 69% of the horses.

Sepsis of the common digital extensor tendon sheath secondary to hemicircumferential periosteal transection in a foal

A 4-month-old Quarter Horse was admitted for evaluation of infection that developed following bilateral hemicircumferential periosteal transection and elevation. Sepsis of the common digital extensor tendon sheath was diagnosed. Treatment included lavage of the tendon sheath, placement of an indwelling drain for lavage after surgery, establishment of drainage, and administration of antimicrobial and anti-inflammatory drugs. Three months after treatment, the foal was clinically normal.

Lateral buccotomy for removal of a supernumerary cheek tooth in a horse

A 3-year-old female Standardbred was admitted for evaluation of a firm swelling on the right side located rostral to the facial crest and a firm intraoral swelling located rostral to the erupted cheek teeth. Examination of skull radiographs revealed a supernumerary cheek tooth rostral to the erupted third premolar. The supernumerary tooth was removed via lateral buccotomy. The horse did not have complications after surgery and resumed racing. Lateral buccotomy should be considered for removal of rostrally located maxillary or mandibular cheek teeth. Supernumerary cheek teeth can be found in locations in the upper dental arcade, other than caudal to the last molar.

Alar fold resection in horses: 24 cases (1979-1992)

Between 1979 and 1992, the alar folds were resected bilaterally in 22 horses and unilaterally in 2 horses. Abnormal respiratory tract noise and exercise intolerance were the primary complaints prior to surgery. Significantly (P = 0.01) more Standardbreds underwent resection of the alar folds, compared with the number of Standardbreds in the hospital population during the same period. The alar folds palpated abnormally thick in 13 horses and normal in 11 horses. Temporary dilatation of the nares with mattress sutures or clips lessened the respiratory tract noise and improved exercise tolerance in all 8 horses in which the diagnostic test was performed. Manual elevation of the alar folds reduced respiratory noise in the 11 horses evaluated. Long-term follow-up evaluation by telephone was available for 14 horses. All surgical incisions had healed cosmetically. Respiratory tract noise was decreased, and exercise tolerance improved in 10 of 14 (71%) horses. Complete charted racing information was obtained for 16 horses. Fourteen horses started their first race a mean of 118 days (range, 13 to 321 days) after surgery. The mean number of starts after surgery was 51, with 14 of 16 (88%) horses starting more than 6 times after surgery. Of the 16 horses, 8 horses raced at least 3 times before and after surgery; 4 had improved racing performance, 2 had similar performance, and 2 had decreased performance. Five Standardbreds never raced, and 1 Standardbred raced once before surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of pharmacologically induced ejaculation to obtain semen from a stallion with a fractured radius

Ejaculation was pharmacologically induced in a 13-year-old Quarter Horse stallion with a spiral fracture of the radius. The owners desired to have semen from the stallion frozen prior to euthanatizing the horse, but because of the debilitating injury, standard methods of semen collection could not be used. With the stallion standing quietly in a stall, a plastic collection bag was positioned over the stallion's penis, and clomipramine hydrochloride (2.2 mg/kg of body weight, IV) was administered. Fifty-five minutes later, xylazine hydrochloride (0.5 mg/kg, IV) was administered. The stallion ejaculated 2 minutes after xylazine administration. The semen sample was of low volume and had a high concentration of spermatozoa; however, motility of spermatazoa was poor and the semen was unacceptable for freezing. The stallion was euthanatized. Semen aspirated from the epididymis after euthanasia was of similar quality to that of the ejaculated sample. Pharmacologic induction of ejaculation can be useful for obtaining semen from stallions when standard techniques cannot be applied.

Transection of the accessory ligament of the superficial digital flexor muscle for the treatment of superficial digital flexor tendinitis in standardbreds: 40 cases (1988-1992)

Medical records of 40 racing Standardbreds with superficial digital flexor tendinitis that underwent transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) were reviewed. Surgery was performed bilaterally in 32 horses and unilaterally in 8. Concurrent palmar annular desmotomy was performed in 8 horses in which tendinitis involved the distal metacarpal region and confinement of the deep and SDF tendons by the annular ligament was suspected. Follow-up information was obtained for 32 horses, by telephone, and racing results were available for 39 horses (1 horse is currently in training, but had a qualifying race prior to surgery). Tendinitis recurred in 8 of 32 (25%) horses that returned to training. Thirty-five of 38 (92%) horses started at least 1 race after surgery. Mean +/- SD time between surgery and first race was 237 +/- 86 days. Overall, 33 of 38 horses completed 5 or more races after surgery; however, SDF tendinitis recurred in 6, and treatment was, therefore, considered to be successful in 27 horses. Horses started a median of 18 races after surgery. Median amount of money won per start after surgery (median, $418; range, $0 to $4,626) was significantly less than median amount won per start before surgery (median, $1,155; range, $0 to $14,603). Inflammation of the interosseous muscle (suspensory ligament) developed in 5 horses with bilateral SDF tendinitis and in 2 horses with unilateral SDF tendinitis. All horses with inflammation of the interosseous muscle had undergone bilateral superior check desmotomy.

Epiglottitis in horses: 20 cases (1988-1993)

Epiglottitis was diagnosed and treated in 20 horses (13 Thoroughbreds and 7 Standardbreds) over a 5-year period. Eighteen horses were used for racing, and 2 Standardbreds were broodmares. Primary clinical signs were exercise intolerance, respiratory noise, and coughing. The most common endoscopic diagnosis made by referring veterinarians was epiglottic entrapment (11 horses). In 19 horses, endoscopic evaluation at admission revealed mucosal ulceration and thickening of the lingual surface of the epiglottis. Other endoscopic findings included dorsal displacement of the soft palate (14 horses), and dorsal deviation of the epiglottic axis (11 horses). Only 1 horse had epiglottic entrapment. Treatment consisting of stall confinement for 7 to 14 days, topical administration of a solution of furacin, dimethyl sulfoxide, glycerin, and prednisolone, and systemic administration of nonsteroidal anti-inflammatory drugs and corticosteroids was effective in controlling epiglottic edema and inflammation. Antimicrobials were administered to 6 horses. Racing performance of the 18 racehorses was evaluated by examination of racing records. One horse was still convalescing at the time of the study, and 1 horse had been euthanatized 1 week after treatment for epiglottitis because of colic. The remaining 16 horses all started at least 1 race (mean time between initial examination and start of first race, 74 days; range, 8 to 265 days). Thirteen horses started at least 4 races following treatment for epiglottitis; racing performance after treatment was the same in 8 and decreased in 5. Long-term sequelae of epiglottitis included epiglottic deformity (5 horses), intermittent or persistent dorsal displacement of the soft palate (4 horses), and epiglottic entrapment (1 horse).

Peritonitis in horses: 67 cases (1985-1990)

Peritonitis was diagnosed in 67 horses between 1985 and 1990: 14 horses developed septic peritonitis after intestinal rupture, 25 horses developed peritonitis after abdominal surgery, and 28 horses had peritonitis not associated with intestinal rupture or abdominal surgery. Forty of 67 horses (59.7%) did not survive. Nonsurvivors had higher heart rates (P = 0.01), RBC count (P = 0.039), serum creatinine concentration (P = 0.036), PCV (P = 0.007), and anion gap (P = 0.005); lower venous blood pH (P = 0.002); and a greater number of bacterial species cultured from peritoneal fluid samples (P = 0.054), compared with those from survivors. Nonsurvivors were more likely to have signs of abdominal pain (P < 0.000), circulatory shock (P = 0.009), and bacteria in peritoneal fluid samples (P = 0.042). Physical examination and peritoneal fluid analysis were the most valuable diagnostic aids for intestinal rupture. Peritonitis after abdominal surgery resulted in high mortality (56%); peritonitis not associated with intestinal rupture or abdominal surgery had lower mortality (42.9%). Clinical and laboratory indices can be of value in determining the prognosis for horses with peritonitis.

Small intestinal incarceration through the lateral ligament of the urinary bladder in a horse

Small intestinal incarceration through the lateral ligament of the urinary bladder was diagnosed in a 14-year-old, 569-kg, castrated Quarter Horse. The incarceration was corrected by ventral midline celiotomy. Approximately 70 cm of the middle portion of the jejunum was resected and end-to-end, single-layer anastomosis was performed. After surgery, the horse developed signs of adynamic ileus and lameness in the right forelimb. The horse developed laminitis in all 4 feet within 24 hours of surgery. The horse was euthanatized because of poor prognosis for survival. At necropsy, a 4.5-cm rent was found in the left lateral ligament of the urinary bladder. The cause of the rent in the ligament of this horse was not determined.