Effect of ligation on internal carotid artery blood pressure in horses.

The effect of a single ligature on back pressure in the internal carotid artery was studied in nine horses. In six anesthetized horses, one internal carotid artery was catheterized 2 cm from its origin and blood pressure was recorded continuously. Then the artery was ligated, pressure was recorded again, and the horses were euthanatized. In another three anesthetized horses, indwelling catheters were placed in both internal carotid arteries and a loose ligature was placed proximal to one catheter. After horses recovered from anesthesia, the ligature was tied and blood pressure was recorded in both arteries on that day and 3 days later, then these horses were euthanatized. The anatomy of the cerebral arteries was examined in all nine horses. Blood pressure in the internal carotid arteries did not change after ligation. Subjectively, collateral channels considered most likely to maintain blood pressure in the ligated internal carotid artery were the caudal intercarotid artery and the cerebral arterial circle. We concluded that ligation of the internal carotid artery would not prevent severe hemorrhage from the internal carotid artery in horses with guttural pouch mycosis until the ligated artery thrombosed to the level of the lesion.

Use of a bovine hemoglobin preparation in the treatment of cyclic ovarian hemorrhage in a miniature horse.

Anemia that was secondary to ovarian hemorrhage in a 4-year-old miniature horse mare was treated prior to laparotomy with polymerized ultrapurified bovine hemoglobin (PUBH). Two previous whole-blood transfusions had resulted in acute transfusion reaction, and a suitable blood donor could not be found among 9 horses, necessitating use of the blood substitute. Subsequent blood typing revealed the mare to be Aa-negative, with allo-antibodies against Aa in serum. Serious adverse reactions were not observed after infusion of PUBH, and the mare recovered. Although the safety and efficacy of using PUBH in horses has not been established, PUBH may prove to be an excellent alternative to whole-blood transfusions, when indicated.

Diagnosis and prediction of cervical vertebral malformation in thoroughbred foals based on semi-quantitative radiographic indicators.

Over a period of 5 years on a central Kentucky Thoroughbred stud farm 132 foals were evaluated for the presence of cervical vertebral malformation (CVM). Lateral cervical vertebral radiographs were obtained on 70 standing foals. These radiographs were evaluated semi-quantitatively and scored numerically for the presence of stenosis of the vertebral canal, enlarged physeal growth plates, caudal extension of the dorsal border of the orifice of the vertebral canal, angular fixation, delayed ossification of bone and degenerative joint disease. From these scores a total CVM score was given for each set of radiographs. All foals were repeatedly examined for clinical signs of neurological disease. Foals with no clinical signs of CVM had maximal total CVM scores (mean +/- sd) of 5.7 +/- 2.8 and foals affected with CVM had maximal total CVM scores of 17.0 +/- 2.8. Determination of the total CVM score was non-invasive, inexpensive and a very accurate procedure for predicting and diagnosing the presence of CVM in Thoroughbred foals up to 1 year of age.

Loop colostomy for management of rectal tears and small-colon injuries in horses: 10 cases (1976-1989).

Loop colostomy was performed in 10 horses as treatment for grade-III rectal tears (n = 6 horses), small-colon infarction (n = 2 horses), perirectal abscess and stenosis (n = 1 horse), and small-colon stricture (n = 1 horse). In 7 horses, the colostomy was constructed through a single incision low in the left flank, with closure of the incision around the stoma (single-incision technique). In 3 horses, 2 of which had colostomy performed as a standing procedure, the selected segment of small colon was placed from a flank incision into a separate, small incision low in the left flank (double-incision technique). Five horses underwent colostomy reversal (at 18 to 63 days) and 2 of these horses, both with grade-III rectal tears, recovered completely. Of 8 horses that did not survive, 6 died from the primary disease or associated complications. Technical problems associated with colostomy accounted for death of 2 horses. One horse had gastric rupture attributable to suture occlusion of the small intestine after colostomy reversal, and another horse had complications of incisional infection after repair of a peristomal hernia. Small-colon prolapse through the stoma necessitated premature reversal of the colostomy in a horse that was euthanatized because of worsening laminitis. Minor complications of the colostomy procedure were partial stomal dehiscence (n = 4 horses), partial dehiscence of the flank wound after colostomy reversal (n = 2 horses), and small ventral midline hernia after colostomy reversal (n = 1 horse). Loop colostomy may be of benefit to horses with rectal tears, provided it is done soon after the tear occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical management and surgical repair of atresia coli in calves: 66 cases (1977-1988).

The medical records of 66 calves with atresia coli were reviewed; 64 calves were examined at the New York State College of Veterinary Medicine, and 2 calves were examined at the New Bolton Center. In each case, the site of the atresia was within the spiral loop of the ascending colon. In 1 of these calves, a segment of jejunum was also atretic. Absence of feces, progressive weakness, and abdominal distension were the most common clinical signs observed. Other congenital abnormalities were detected in 12 (18%) of 66 calves. Of the 66 calves examined, 5 were euthanatized or died on admission, and 61 had an exploratory celiotomy performed. Eight calves were euthanatized or died during the surgery. In the remaining 53 calves, surgical treatment consisted of enterotomy followed by meconium evacuation, resection of the proximal blind end (in 30 calves), and restoration of intestinal continuity. Restoration of intestinal continuity was done either by side-to-side anastomosis of the proximal to distal blind ends (5 calves), or by side-to-side or end-to-side anastomosis of the proximal blind end to the descending colon (48 calves). Of the 66 calves seen, 27 (41%) were discharged from the hospital, and 11 of these reached reproductive age (11 calves were lost to follow-up before they were 2 years old). From the 11 calves reaching reproductive age, 33 calves were born, one of which may have had atresia coli. The owners should anticipate that long-term survivors likely will have loose feces and normal offspring, but may not grow as well as otherwise expected.

In vitro transport of cycloleucine by equine cecal mucosa.

Mucosa obtained from the cecum of healthy horses and incubated in vitro with 0.1 mM cycloleucine could accumulate this amino acid against an apparent concentration gradient after 60 and 120 minutes. Accumulation by the serosal (antiluminal) surface of the tissue was 3 times greater than accumulation by the mucosal (luminal) surface after 120 minutes (P less than 0.001). Cycloleucine accumulation was significantly reduced by Na deprivation after 60 minutes (P less than 0.05) and 120 minutes (P less than 0.01) and by anoxic conditions after 120 minutes (P less than 0.05). Transmucosal flux from mucosal to serosal surface of the tissue was significantly (P less than 0.05) greater than the opposing flux, but both unidirectional fluxes were small and were largely attributed to passive processes. It was concluded that the most avid transport system for cycloleucine was on the serosal surface of the horse's cecal mucosa, and an active transport system was not evident on the mucosal surface. An active transport system for amino acids on the serosal surface could be explained by the need for crypt cells, the predominant epithelial cell type in the cecum, to obtain nutrients from blood, rather than from the intestinal lumen.

Third-degree perineal lacerations and rectovestibular fistulae in cattle: 20 cases (1981-1988).

The case records of 20 cows with either a third-degree perineal laceration or rectovestibular fistula were reviewed to ascertain the signalment, history, treatment, and long-term result of treatment. Fifteen cows, including 10 first-calf cows, had third-degree perineal lacerations that occurred at calving. Surgery was done in 14 of 15 cows; 10 of the 14 (71%) remained fertile. The cow that was not treated surgically was culled after 24 months because of infertility. Five cows had a rectovestibular fistula; 4 of these were treated surgically. The cow that did not have surgery healed by second intention and remained fertile, and 3 of the 4 cows in which surgery was performed were fertile. None of the cows that produced calves after the initial injury suffered a perineal laceration at subsequent calvings. Single-stage surgical repair of third-degree perineal laceration or rectovestibular fistula appeared to have a good prognosis for subsequent fertility in cows.

In vitro transport of L-alanine by equine cecal mucosa.

When sheets of mucosa from the cecum of clinically normal horses were incubated in vitro with radiolabeled L-alanine, they could accumulate this amino acid against an apparent concentration gradient after 60 to 150 minutes of incubation. The active transport system for L-alanine was on the serosal surface of the mucosal sheet only. L-Alanine accumulation at 60 minutes was partly inhibited by 20 mM glycine (P less than 0.01), 0.5 mM ouabain (P less than 0.05), and Na deprivation (P less than 0.02). Anoxia for 60 minutes increased L-alanine accumulation, but had adverse effects on cell structure and intracellular cation distributions. Transmucosal fluxes induced a small, but significant (P less than 0.05), net secretion of L-alanine, and the mean (+/- SEM) transmucosal potential difference was 7.3 +/- 0.7 mV over the period of flux measurement. It was concluded that L-alanine was accumulated by the serosal surface of the cecal mucosa, possibly to provide substrate for tissue metabolism. There was no evidence that the cecal mucosa could actively transport this amino acid from the luminal bathing medium.

Equine class II MHC antigens: identification of two sets of epitopes using anti-human monoclonal antibodies.

Six mouse and 13 rat monoclonal antibodies (mAb) recognizing HLA-DR, DQ and DP antigens were used for the detection of cell surface class II MHC antigens of equine lymphocytes. The monoclonal antibodies were tested against peripheral blood lymphocytes (PBL) from a panel of thoroughbred horses, using two-color fluorescence flow cytometry. Seven of these mAbs reacted with both surface immunoglobulin positive (sIg+) and surface immunoglobulin negative (sIg-) lymphocytes. sIg+ cells stained consistently brighter than sIg- cells. The fluorescence pattern did not vary from donor to donor for each of the mAbs tested, except for SFR1-MI.2, which reacted with a variable intensity with cells from 47 of 53 horses tested. Immunoprecipitation with mAb SFR1-MI.2 and analysis by two-dimensional electrophoresis demonstrated the presence of light and heavy chains equivalent to HLA class II alpha and beta chains. Antibody N297 (DQ specific), previously shown to react with an epitope expressed on human B cells but not on mitogen-induced T cells, reacted only with sIg+ cells in 42 of 53 horses tested. The lack of staining of horses sIg- cells with N297 may be due to a low or lack of expression of this determinant on these cells or to a weak cross-reactivity of this antibody with equine antigens.

Guttural pouch tympany: 15 cases (1977-1986).

From 1977 to 1986, guttural pouch tympany was diagnosed in 15 horses--11 fillies and 4 colts. Review of the medical records provided results of physical, microbiologic, radiographic, and endoscopic examinations, treatment protocols, complications, and recovery rate. All affected horses had visible swelling in the parotid gland region, 9 had abnormal respiratory noise, 5 had pneumonia, and 1 had dysphagia. Six horses were treated by median septum fenestration alone, and in 8 horses, this procedure was combined with resection of the mucosal flap at the pharyngeal orifice of the eustachian tube. One horse was not treated. Follow-up information was obtained for 13 horses. Rate of recurrence was 33% (2/6) after fenestration alone and was 29% (2/7) when both procedures were combined. One horse that had been treated using combined procedures died of pneumonia, and a horse treated unsuccessfully by septum fenestration was euthanatized because of persistent dysphagia. Eight horses greater than 2 years old when follow-up information was obtained were reported to be healthy, and 4 of these had raced successfully.

The use of skin expansion to repair cosmetic defects in animals.

Skin expansion was used in three horses, one heifer, and one dog to aid in the repair of cosmetic defects. Skin expansion was produced by inserting an expandable silicone device subcutaneously and gradually inflating the device with saline. Skin expansion allowed skin to be mobilized and sutured over cosmetic defects without excessive tension. A successful outcome was achieved in four of the five cases reported here. In one animal, two attempts to create a pocket for a silicone prosthesis failed because the expanders ruptured. Complications included implant failure, wound dehiscence, and exposure of an expander. Skin expansion can be used to enable closure of skin defects in areas where skin tension usually precludes repair by local transposition.

Occlusion of the external carotid and maxillary arteries in the horse to prevent hemorrhage from guttural pouch mycosis.

Balloon-tipped catheters were used to occlude the external carotid artery and its branches in nine horses with hemorrhage caused by guttural pouch mycosis. The internal carotid artery on the affected side was occluded simultaneously in four horses and had been occluded previously in two others. In three horses, a single balloon-tipped catheter was inserted in the external carotid artery beneath the floor of the guttural pouch and its tip was advanced blindly into distal branches. In one horse, the superficial temporal artery was occluded briefly during surgery by a balloon-tipped catheter so a catheter inserted into the external carotid artery could be diverted into the maxillary artery. In the other five horses, the external carotid artery was occluded proximally and the maxillary artery was occluded immediately caudal to the alar canal by a balloon-tipped catheter inserted into the major palatine artery. Serious postoperative hemorrhage did not occur in eight horses, but one horse that had a single balloon-tipped catheter inserted into the external carotid artery had profuse hemorrhage 11 days after surgery and was euthanatized. One horse was euthanatized because of persistent dysphagia. The only complication related to use of balloon catheters was a mild incisional infection in one horse. It was concluded that the external carotid and maxillary arteries must be occluded on both sides of the eroded segment to prevent hemorrhage from normograde and retrograde flow.

Hepaticojejunostomy for treatment of common hepatic duct obstructions associated with duodenal stenosis in two foals.

Two female Standardbred foals 2 and 3 months of age were presented with signs of gastroduodenal obstruction that was confirmed with contrast radiography and exploratory surgery. Ventral midline celiotomy was performed, showing stenosis of the duodenum proximal and distal to the hepatopancreatic ampulla. The common hepatic duct, the pancreatic duct, and the sigmoid section of the duodenum proximal to the stenosis were greatly dilated. To bypass the intestinal obstruction, a side-to-side duodenojejunostomy was performed. Obstruction of the common hepatic duct was relieved by side-to-side hepaticojejunostomy. In addition, jejunojejunostomy was performed distal to the other anastomoses. Both foals recovered. On admission, the foals' total bilirubin, aspartate aminotransferase, and gamma glutamyl transferase levels were greatly elevated. During the subsequent 6 to 8 months, they returned to normal. Six months after the first surgery, one foal was readmitted with an acute abdominal crisis. At surgery, there was greater than 360 degrees clockwise rotation of the mesenteric root involving most of the jejunum. At necropsy, the previously created stomas were patent. The liver and bile duct were grossly and histologically normal. The second foal continues to progress normally 12 months after surgery.

Diagnosis and surgical correction of patent ductus venosus in a calf.

Patent ductus venosus was diagnosed in a 10-week-old Holstein heifer with acute onset of collapse and marked tenesmus. Additional clinical signs observed during the course of hospitalization included depression, anorexia, hind limb ataxia, bruxism, and poor growth. Clinicopathologic test results included high blood ammonia concentration, prolonged sulfobromophthalein half-life, and high serum bile acid concentration. Liver biopsy revealed mild periportal fibrosis, but no appreciable hepatocyte atrophy. Mesenteric portography and percutaneous ultrasonography confirmed the patent ductus venosus. An atrial septal defect prosthesis was placed in the ductus venosus, using a catheterization technique. After surgery, however, clinicopathologic test results were unchanged. Ultrasonography revealed that the prosthesis had pulled away from one side of the vessel. When the calf was 10.5 months old, surgical correction was achieved by a transhepatic ligation technique. Ultrasonography confirmed closure of the ductus venosus during and after surgery. Blood ammonia and serum bile acid concentrations and sulfobromophthalein half-life were normal 3 weeks after surgery. The calf had no further episodes of hepatoencephalopathy and was successfully bred at 18 months of age.

Prognostic index for acute abdominal crisis (colic) in horses.

Selected physical and laboratory findings in 29 horses with acute abdominal crisis were evaluated retrospectively with a logistic regression equation to predict survival or death. Of 17 variables examined, 2 were found to have good predictive correlation. Serum lactate and packed cell volume had a combined predictive value of 94%. Packed cell volume mean values of 43 and 50%, respectively, differentiated survival from death. Serum lactate values of 28.18 mg/dl and 51.28 mg/dl differentiated survival and death. Analysis of data from a previous study of 36 horses with the logistic regression equation predicted survival rate of 96% accuracy, further substantiating the statistical model.

Esophageal duplication cyst as a cause of choke in the horse.

A mare was examined for episodic choking and an abscess in the perilaryngeal region. One month before referral, the mass progressively enlarged, causing esophageal choking. An extraluminal compression of the esophagus 90 cm from the external nares was found on endoscopy and contrast radiography. Serosanguinous fluid aspirated from the mass contained keratinized squamous cells and neutrophils, compatible with an esophageal cyst. Surgical exploration was performed, with incomplete surgical excision. The remaining portion of the cyst was marsupialized and treated locally with a 2% inorganic iodine solution. Further episodes of esophageal choke in this horse have not been reported.

Omental fibrosarcoma in a horse.

A 13-year-old Thoroughbred mare had a 2-week history of weight loss and intermittent fever. Examination of abdominal and pleural fluid revealed peritonitis and pleuritis. Ultrasonography of the ventral abdominal midline revealed an intra-abdominal mass. Exploratory celiotomy was performed, but the mass was not surgically excisable. The mare was euthanatized and necropsied. Histologically, the mass was determined to be a fibrosarcoma of omental origin.

Implantation of a permanent transvenous pacing catheter in a horse with complete heart block and syncope.

A permanent, transvenous, atrioventricular, sequential pacing system was implanted successfully in a 7-year-old Quarter Horse gelding with complete heart block. The transvenous atrial and ventricular electrodes were placed in their respective positions in the heart, using real-time, 2-dimensional echocardiography. The horse was able to return successfully to competition as a show horse.

Normal motility of the cecum and right ventral colon in ponies.

To study the normal motility of the cecum and right ventral colon (RVC) in 3 mature Shetland ponies, a 6-part, indwelling, intraluminal catheter system was used to measure intraluminal pressure changes. Three catheters were placed in the cecum at 10, 25, and 40 cm from the cecocolic orifice, and 3 catheters were placed in the RVC at 10, 20, and 30 cm from the cecocolic orifice. Recordings were made during the interdigestive period beginning 2 weeks after surgical operation was done. Frequent, low-amplitude peaks (0.35 +/- 0.13 coordinated peaks/min) were seen involving the cecal body and caudal cecal base, which represented a haustra-to-haustra mixing pattern. Coordinated pressure peaks originated in the cecal body and progressed to the cranial cecal base (0.07 +/- 0.01/min) or originated in the cranial cecal base and progressed to the cecal body (0.07 +/- 0.04/min). Associated with a loud rush of ingesta heard on transabdominal auscultation and progression of liquid ingesta confirmed with barium contrast radiography, there was a series of coordinated, progressive pressure peaks which originated in the cecal body, sequentially involved the cecal base, traversed the cecocolic orifice, and extended into the RVC (0.36 +/- 0.05/min). It seemed that a pacemaker region existed in the cecal body and initiated the important aborally propagated progressive pattern responsible for the transit of ingesta from the cecum to the RVC. A separate mechanism for the transit of gas was not identified. In the RVC, infrequent, nondirectional, low-amplitude segmental pressure peaks (0.12 +/- 0.06/min), and aborally progressive coordinated pressure peaks originating at the beginning of the RVC (0.09 +/- 0.02/min), occurred.(ABSTRACT TRUNCATED AT 250 WORDS)