Patterns of expression of muscle-specific markers of differentiation in satellite cell cultures: determination by enzyme-linked immunoculture assay and confocal immunofluorescent assay.

Equine satellite cell clone SE-11 and ovine satellite cell clone I(1)were evaluated for expression of myosin heavy chain, myogenin, desmin, and muscle-specific actin over a 240 h period in culture. An enzyme-linked immunoculture assay (ELICA) was capable of detecting these proteins at all time points evaluated. A linear relationship was demonstrated between the natural logarithm of the absorbance values (corrected for cell number) from the ELICA and percent fusion in both SE-11 and I(1)cultures. The r(2)values for SE-11 cultures were: desmin 0.82, muscle actin 0.81, myogenin 0.78, and myosin 0.70. The r(2)values for I(1)cultures were: desmin 0.77, muscle actin 0.72, myogenin 0.70, and myosin 0.61. Our confocal results support the idea that differences exist between species in the differentiation dynamics of satellite cells. Further, these data suggest that the ELICA may be applied to previously conducted experiments, enabling additional data to be obtained with relation to muscle protein expression.

Cardiopulmonary function in horses during anesthetic recovery in a hydropool.

OBJECTIVE: To determine the cardiovascular and respiratory effects of water immersion in horses recovering from general anesthesia. ANIMALS: 6 healthy adult horses. PROCEDURE: Horses were anesthetized 3 times with halothane and recovered from anesthesia while positioned in lateral or sternal recumbency in a padded recovery stall or while immersed in a hydropool. Cardiovascular and pulmonary functions were monitored before and during anesthesia and during recovery until horses were standing. Measurements and calculated variables included carotid and pulmonary arterial blood pressures (ABP and PAP respectively), cardiac output, heart and respiratory rates, arterial and mixed venous blood gases, minute ventilation, end expiratory transpulmonary pressure (P(endXes)), maximal change in transpulmonary pressure (deltaP(tp)max), total pulmonary resistance (RL), dynamic compliance (Cdyn), and work of breathing (W). RESULTS: Immersion in water during recovery from general anesthesia resulted in values of ABP, PAP P(endXes), deltaP(tp)max, R(L), and W that were significantly greater and values of Cdyn that were significantly less, compared with values obtained during recovery in a padded stall. Mode of recovery had no significant effect on any other measured or calculated variable. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in pulmonary and cardiovascular function between horses during recovery from anesthesia while immersed in water and in a padded recovery stall were attributed to the increased effort needed to overcome the extrathoracic hydrostatic effects of immersion. The combined effect of increased extrathoracic pressure and PAP may contribute to an increased incidence of pulmonary edema in horses during anesthetic recovery in a hydropool.

Dorsally recumbent female equine urogenital endoscopic surgery.

The ventral abdominal approach for laparoscopy is versatile. Reported techniques using a ventral approach in the mare include bilateral ovariectomy and granulosa cell tumor removal. Laparoscopic ovariectomy is performed by way of four instrument portals in the caudoventral aspect of the insufflated abdomen. The procedure has several advantages over the traditional approaches of colpotomy and celiotomy, including tension-free closure of all incisions and minimal invasiveness.

Dorsally recumbent urinary endoscopic surgery.

Laparoscopic cystotomy is the method of choice for treatment of a cystic calculus in the horse. The main advantage of this procedure over others is the excellent ability to view and gain operative access to the urinary bladder. This article describes the procedure, including techniques, instrumentation, preoperative and postoperative care, and complications.

Repeated manual evacuation for treatment of rectal tears in four horses.

Horses with tears that involve all layers of the rectum except the mesocolon (grade IIIb) have a poor prognosis for survival because of the difficulty in treating these wounds and the propensity for them to progress to full perforations (grade IV). Most treatments for grade-IIIb rectal tears involve surgery of some kind, but not all grade-IIIb rectal tears require surgical intervention. We report on 4 horses with grade-IIIb rectal tears that were evaluated via palpation per rectum and endoscopy. Two of 4 horses were admitted with signs consistent with shock and endotoxemia, and evaluation of all peritoneal fluid samples was indicative of nonseptic peritonitis. Horses were treated via administration of antibiotics and anti-inflammatory drugs and repeated manual evacuation of the terminal portion of the small colon and rectum. Treatment centered on preventing further enlargement of the rectal tear by eliminating the storage function of the terminal portion of the small colon and rectum. None of our horses had worsening of the original injury, and horses were discharged within 2 weeks of admission with full resolution of the rectal tear. Outcomes in the horses of our report indicate that repeated manual evacuation can be successful for treatment of horses with grade-IIIb rectal tears.

Culture and characterization of equine terminal arch endothelial cells and hoof keratinocytes.

OBJECTIVES: To develop methods to isolate, culture, and characterize equine hoof endothelial cells (EC) and keratinocytes. SAMPLE POPULATION: Cells harvested from the forelimbs of 8 horses. PROCEDURE: EC were obtained via catheters placed in the palmar digital arteries of the disarticulated lower portion of the forelimbs from 4 horses that had been heparinized prior to euthanasia. Phosphate-buffered saline solution was used to remove and discard RBC from blood vessels, and collagenase was used to loosen and flush EC from the vasculature. Hoof keratinocytes were obtained from 4 recently euthanatized horses by use of dispase/trypsin dissociation of the coronary band epidermis. Use of an extracellular matrix gel as a culture flask attachment factor was important to the success of hoof keratinocyte cultures. RESULTS: EC from the palmar digital arteries were successfully cultured and characterized by in vitro morphology, uptake of a fluorescence-labeled acetylated-low density lipoprotein, and lack of expression of von Willebrand factor and smooth muscle actin. Hoof keratinocytes were characterized by morphology in culture and expression of keratin proteins, as determined by immunochemical reaction. Keratinocyte cultures were also positive for vimentin expression. CONCLUSIONS: Culture techniques to isolate and characterize hoof cells should aid investigators in their study of equine hoof pathobiologic features, especially as it relates to laminitis.

Laparoscopic diagnosis of subcapsular splenic hematoma in a horse.

A 5-year-old Quarter Horse was examined after it developed signs of abdominal discomfort as a result of a training accident. Oral mucous membranes were pale, and capillary refill time was > 3 seconds. Hematologically, the PCV was low, and abdominocentesis yielded a serosanguineous fluid. Abdominal ultrasonography was performed and revealed a large hypoechoic mass associated with the cranial margin of the spleen. Because differentiation between subcapsular hematoma and extracapsular hematoma could not be made with certainty, further evaluation of the spleen was indicated. Abdominal laparoscopy was performed, with the horse standing, to evaluate the extent, severity, and nature of the splenic hematoma. Laparoscopic examination revealed a 7.5-cm-diameter splenic hematoma contained within the splenic capsule, confirming the diagnosis of subcapsular splenic hematoma. Abdominal laparoscopy provided excellent observation of the spleen and allowed for thorough evaluation and determination of the extent of the lesion. This information aided the clinician in reaching a definitive diagnosis and choosing between splenectomy and medical treatment.

Bone scintigraphy in the diagnosis of sacroiliac injury in twelve horses.

Nuclear bone scintigraphy was used to diagnose sacroiliac injury in 12 horses presented for nonspecific rear limb lameness. The most common history was decreased performance and/or a mild chronic rear limb lameness which could not be localised by routine lameness examination. The scintigraphic patterns of the 12 affected horses were compared to 5 normal horses and 10 horses with lameness not related to the pelvic region. Subjective and quantitative evaluation of the bone scans clearly separated the 12 affected horses from the 5 normal horses and the 10 horses with lameness from causes other than the sacroiliac joint disease. The 12 affected horses had a scintigraphic pattern of moderate to marked increased uptake of the radiopharmaceutical within the sacroiliac joint region on the side of lameness. In contrast, the 5 normal horses and 10 horses scanned for other causes of lameness, had a symmetric, or only slightly asymmetric pattern of radioisotope uptake. Although nonspecific for the type of injury, nuclear bone scintigraphy is considered sensitive for the detection of sacroiliac injuries in horses.

Ventral abdominal approach for laparoscopic cryptorchidectomy in horses.

OBJECTIVE: To report a ventral abdominal approach and a ligating loop technique for laparoscopic cryptorchidectomy in horses. STUDY DESIGN: Prospective. SAMPLE POPULATION: Six horses, aged 1 to 5 years, with retained testes. METHODS: One laparoscopic portal and three to four instrument portals were used for ventral abdominal laparoscopic cryptorchidectomy. Laparoscopic instruments were used to maneuver and secure the testis through a ligating loop (modified Roeder knot) that was secured from outside the abdominal cavity. Only minimal enlargement of one instrument portal was used to remove the testicle. RESULTS: Three horses were bilateral cryptorchids, and three were unilateral (left side, two; right side, one) cryptorchids. Operative time, defined as the time from laparoscope insertion to removal, ranged from 20 to 25 minutes for unilateral cryptorchids and from 40 to 50 minutes for bilateral cryptorchids. CONCLUSIONS: The reported technique allowed decreased tension on the tissues during ligation and removal of the testis from the peritoneal cavity. Improved observation of the abdominal cavity, ligation security, shortened patient confinement time, and minimally invasive technique are all considered to be benefits of laparoscopic cryptorchidectomy. CLINICAL RELEVANCE: Direct observation of retained testes and intraabdominal castration are distinct advantages of the use of laparoscopy in horses that have had previous unsuccessful surgical attempts, horses with unknown histories that have retained testicular tissue, or bilateral abdominal cryptorchids.

Injury to abdominal wall vessels during laparoscopy in three horses.

Epigastric vessels were inadvertently injured during placement of instrument portals in 3 horses undergoing laparoscopy for bilateral cryptorchidectomy, bilateral ovariectomy, and removal of electrode wires surgically implanted in the large colon. The resulting hemorrhage increased surgery time, caused hematoma formation or hemoperitoneum, and obscured the surgical field. Hemostasis was achieved by direct pressure or vessel ligation. This complication can be attributed to the high degree of vascularity of the ventral aspect of the abdominal wall.

Use of tenoscopy for management of septic tenosynovitis caused by a penetrating porcupine quill in the synovial sheath surrounding the digital flexor tendons of a horse.

A 6-year-old Quarter Horse gelding with acute onset of a grade-4/5 lameness of the left forelimb 21 days after an encounter with a porcupine was examined. Quills had been removed by the referring veterinarian, and the horse had been treated with antibiotics and hydrotherapy for 14 days. The horse was pyretic and had effusion in the digital synovial sheath. Signs of pain were elicited on palpation of the area. A tentative diagnosis of septic tenosynovitis caused by a porcupine quill was made. Exploratory tenoscopy revealed large amounts of fibrin in the sheath and a 1.2-cm quill. Bacteriologic culture of synovial fluid yielded a pure growth of Staphylococcus aureus. The horse improved dramatically after tenoscopic removal of the quill, debridement of fibrin, and lavage to dilute inflammatory mediators and bacteria, debridement of fibrin, discovery and removal of a quill, and complete evaluation of the sheath for prognostic purposes. Tenoscopy can provide a means for direct observation and enhance the ability of clinicians to debride a septic synovial sheath in a minimally invasive manner.

Laparoscopic diagnosis of ischemic necrosis of the descending colon after rectal prolapse and rupture of the mesocolon in two postpartum mares.

Two mares were referred for evaluation after dystocia and rectal prolapse. Diagnostic laparoscopy, performed while the horses were standing, was used to evaluate the condition of the distal portion of the colon, rectum, uterus, and mesocolon. In both horses, laparoscopic observation revealed tears in the mesocolon of the descending colon. Exploration from the left or right flank was adequate. Because of the poor prognosis associated with the findings, euthanasia was elected at completion of laparoscopy. Tears in the mesocolon are not easily detected by use of traditional tests. Laparoscopy proved to be a more thorough means of evaluating the caudal portion of the abdomen including the digestive and urogenital tracts in these horses. As a less invasive diagnostic tool, laparoscopy can be performed earlier in the course of disease than alternative approaches for direct viewing. Furthermore, laparoscopy can be used to access the viability of tissues as well as the location and severity of lesions for prognostic purposes. The distal portion of the descending colon can also be evaluated to determine whether celiotomy with anastomosis or colostomy may be the surgical procedure of choice.

The role of selected cations in the formation of pseudomicelles in aqueous humic acid.

The fluorescence intensity enhancement of a pyrene probe in aqueous humic acid solutions was assessed in terms of added lanthanide and thorium cations. Among the trivalent ions it was found that size played a role, with the small Lu(3+) ion producing the greatest increase in pyrene emission. This was attributed to its superior ability to cause pseudomicellization in the humic acid polymer. Slow kinetic effects were observed, leading to substantial fluorescence enhancement over a period of 7 h. This was ascribed to a continuous aggregation process in aqueous humic acid, leading to ever more viscous microenvironments for the probe molecule.

Anorectal lymphadenopathy causing colic, perirectal abscesses, or both in five young horses.

Enlarged anorectal lymph nodes can cause colic in young horses by obstructing the caudal aspect of the rectum. Dyschezia and clinical signs consistent with abdominal pain were the predominant reasons for evaluation of the 5 young (3 to 15 month old) horses of this report. Digital transrectal palpation revealed a firm mass obstructing the caudal aspect of the rectum in each horse. Results of cytologic evaluation of the masses revealed a lymphoid population of cells in 4 of 5 horses. These nodes regressed over time or became abscesses and drained into the rectum. In 1 horse, detection of a mature abscess and concomitant dysuria necessitated immediate surgical drainage of the mass; however, the other 4 horses were successfully managed medically, thereby avoiding risks associated with surgery of the perirectal area. Anorectal lymphadenopathy should be considered as a differential diagnosis in young horses with colic.

Laparoscopic ovariectomy in two horses with granulosa cell tumors.

Two mares were admitted for ovariectomy of unilateral granulosa cell tumors. Both mares were ovariectomized (1 unilateral and 1 bilateral) by use of a ventral abdominal laparoscopic technique. This approach required tilting the operative table 30 degrees to elevate the pelvis and to allow observation of the ovaries. Using a single laparoscopic portal and 3 to 4 instrument portals, a triangulation technique was used. The ovarian pedicles were isolated and secured via loop ligation. The ovaries then were divided from the ligated pedicle and placed within specimen bags for extraction. The specimen bags then were removed through a ventral midline celiotomy. Using this technique, it was determined that granulosa cell tumors or ovaries of up to 20 cm in diameter can be removed. Laparoscopic ovariectomy provided a means to provide tension-free dissection and ligation of the ovarian pedicle. In comparison to conventional techniques, this may improve suture security and reduce complications related to excessive pedicle tension. Improved observation during surgery, less pedicle tension, and minimal invasiveness made laparoscopic ovariectomy of these 2 mares advantageous.

Ventral abdominal approach for laparoscopic ovariectomy in horses.

Eleven mares and four mules were ovariectomized by a ventral abdominal laparoscopic technique. This approach required tilting the operative table about 30 degrees elevating the pelvis to allow observation of the ovaries. A triangulation technique with a single laparoscopic portal and four instrument portals was used. The ovarian pedicles were ligated and the ovaries were removed through a single enlarged instrument portal. Females ranged in age from 5 months to 18 years. Mean operative time was 44 minutes (range 20 to 90 minutes); mean operative time of the last seven animals was 26 minutes. Signs of abdominal pain occurred in three mules and one mare in the immediate postoperative period. Peritoneal fluid collected from six animals 48 hours after surgery had a mean leukocyte count of 34,463/microL: (range, 21,000 to 62,800/microL), mean protein concentration of 3.1 g/dL (range, 2.2 to 4.6 g/dL), and mean differential leukocyte count of 74% neutrophils and 26% mononuclear cells. The animals were confined for 2 weeks after surgery. Signs of estrus were observed in two mares within 6 months after ovariectomy. All owners reported satisfaction with the results of laparoscopic ovariectomy. The ventral abdominal laparoscopic approach permitted efficient and safe ovariectomy of foals and adults.

Muscle spasms associated with ear tick (Otobius megnini) infestations in five horses.

Severe muscle cramping not associated with exercise was observed in 5 horses. Focal muscle groups in various regions underwent intermittent visible contraction. Intermittent prolapse of the third eyelid, sweating, pawing, muscle tremors, and muscle fasciculations also were observed. Clinical signs often were misconstrued as signs of colic. Percussion of muscle induced contraction of muscle groups. Concentrations of serum electrolytes and the acid-base balance were within reference limits, but activities of creatine kinase and aspartate transaminase were moderately high. Muscle biopsy revealed no abnormalities except for a few necrotic muscle fibers undergoing phagocytosis. Electromyography of 1 horse was suggestive of increased motor unit activity. All horses had Otobius megnini (ear tick) infestations and had recurrence of signs until treatment was initiated for ear ticks.