Endoscope-assisted three-wire technique for extensive nasal septum resection in horses.

OBJECTIVE: To describe a 3-wire method with endoscopic guidance for extensive nasal septum resection. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Thirteen horses with nasal septum diseases. METHODS: In anesthetized horses in left lateral recumbency, endoscopic guidance was used to place obstetrical wires for the ventral and caudal incisions in the nasal septum and a trephine opening was used to place the dorsal wire. The rostral aspect of the septum was incised with a scalpel, followed by incisions with the preplaced wires, and the nasal passages were packed with gauze. Horses were recovered with a temporary tracheotomy. RESULTS: Conversion to intraoral placement of wires was required in two horses, one to correct entangled wires and the other because hemorrhage obscured the endoscopic view. Exercise tolerance was improved postoperatively, abnormal respiratory noise was decreased or eliminated by surgery in all horses, and all owners were satisfied. One Thoroughbred racehorse performed with modest success. CONCLUSIONS: Modification of the 3-wire method was effective and safe for extensive nasal septum removal. Technical complications of the procedure include entangling of wires and intraoperative hemorrhage. CLINICAL SIGNIFICANCE: Endoscopic guidance can be used to place obstetrical wires for nasal septum resection in small horses and precludes use of a large tracheotomy for anesthetic delivery. Reasons for athletic failures were difficult to establish retrospectively, although assessment of postoperative noise at speed might be more relevant to recovery of athletic potential than assessment at slower gaits.

Nonsteroidal antiinflammatory drugs reduce anion secretion and increase apoptosis in equine colonic mucosa ex vivo.

OBJECTIVE: Right dorsal colitis causes chronic colic associated with long-term treatment with nonsteroidal antiinflammatory drugs (NSAIDs). This study was designed to determine if NSAIDs could inhibit anion transporters that protect against intestinal mucosal injury in other species. ANIMALS: 20 healthy horses. METHODS: The effects of indomethacin (INDO) and firocoxib (FIR), on short-circuit current (Isc) in mucosa from the right dorsal colon (RDC) and right ventral colon (RVC) were measured in Ussing chambers by standard electrophysiological techniques. Immunohistochemical methods were used to detect apoptosis (caspase-3) with these NSAIDs and phenylbutazone (PBZ) and to locate the NKCC1 transporter. RESULTS: The Isc in RDC and RVC incubated with INDO or FIR was increased almost 3-fold (P < .0001) by prostaglandin E2 (PGE2) through a system inhibited by loop diuretics (P < .0001). Although these findings and anion replacement studies were consistent with anion secretion, the RDC also displayed an Isc response suggestive of a unique transporter apparently absent in RVC or NSAID-free solutions. In RDC, FIR, INDO, and PBZ induced apoptosis in the lower half of crypts. However, significant differences in apoptotic index were recorded in the RDC between NSAID-treated and control tissues (no NSAID). CLINICAL RELEVANCE: The effects of NSAIDs on Isc were consistent with reduced anion secretion, which could represent the pharmacological equivalent of the transport failure responsible for Cystic Fibrosis (CF) in other species. Failure of anion secretion could interfere with buffering acid from intraluminal fermentation, which could suggest a treatment target for right dorsal colitis.

Repeat Celiotomy-Current Status.

Repeat celiotomy can be lifesaving in horses with a surgically treatable postoperative obstruction, although guidelines for its use are lacking, except for uncontrollable postoperative pain. Overdiagnosis of ileus as the cause of postoperative obstruction could delay a second surgery so the disease progresses beyond a manageable level of severity. Although many horses respond favorably to repeat celiotomy, complications can be severe and life threatening, such as incisional infection and adhesions. Repeat celiotomy does not seem to exacerbate postoperative ileus, despite additional surgical manipulation. An important benefit of repeat celiotomy is termination of hopeless cases, thereby reducing cost and suffering.

Surgical enlargement of the epiploic foramen in horses.

OBJECTIVE: To assess the safety and efficacy of a method for digitally enlarging the caudal aspect of the epiploic foramen (EF). STUDY DESIGN: Healthy horses and clinical cases of EF entrapment (EFE). ANIMALS: Fourteen healthy horses and three clinical cases. METHODS: Through a ventral midline celiotomy under general anesthesia, the EF was enlarged by digital separation of the caudal attachments of the caudate lobe of the liver from right dorsal colon, right kidney, gastropancreatic fold, and pancreas. Healthy horses were euthanized under anesthesia, and the enlarged EF was measured at necropsy. RESULTS: The method used for enlarging the EF did not cause clinically relevant hemorrhage, as determined by visual inspection of the EF in 14 horses at necropsy and by vital parameters under anesthesia in all horses. In clinical cases, EFE was reduced following enlargement of the EF, and no intraoperative complications were encountered. In one clinical case, necropsy at 30 days confirmed partial closure of the enlarged EF. CONCLUSION: The method proposed enlarged the EF safely and effectively. Limitations of the study include the small number of clinical cases and the lack of postoperative follow-up on the healthy horses. CLINICAL SIGNIFICANCE: Enlargement of the EF at its caudal extent should be considered in selected cases of EFE in which manual reduction is difficult or protracted. Although the procedure was safe in this study, knowledge of the anatomy, practice on cadavers, and careful selection of cases with greatest need are recommended before clinical use.

Ex vivo and in vivo evaluation of a modified interrupted Lembert pattern for small intestinal anastomoses in horses.

OBJECTIVE: To compare single-layer anastomoses (modified continuous Lembert [mod-CL] and modified-interrupted Lembert [mod-IL]) and a 2-layer simple continuous anastomosis (2 L; seromuscular and mucosal) for jejunojejunal anastomoses in equine cadavers and to compare ex vivo to in vivo time to complete the anastomosis and stoma size with a mod-IL pattern. STUDY DESIGN: Measurements in jejunum from cadaver and anesthetized horses. ANIMALS: Ten live horses and 18 equine cadavers. METHODS: Time to complete anastomosis, bursting pressures (BP), leakage sites, and anastomotic index (size ratio of anastomotic lumen to control lumen) were recorded. Time to completion and lumen size were compared between in vivo and ex vivo mod-IL patterns. RESULTS: The mod-CL pattern was fastest (8.44 ± 1.30 min, p < .05), and the 2 L pattern was slower (17.07 ± 2.0 min) than the mod-CL and mod-IL (p < .05). The anastomotic index exceeded 100 and did not differ between patterns. Segments reached higher bursting pressures when anastomosed with mod-IL (145.94 ± 24.18 mm Hg) than mod-CL (p < .05). In vivo closure was approximately 8 minutes slower than ex vivo, and with a smaller anastomotic index. CONCLUSIONS: All anastomoses increased lumen size over control segments ex vivo. Lumen size after placement of a mod-IL was greater ex vivo than in vivo, and completion was slower in vivo than ex vivo. [Corrections added on 26 Dec 2022, after online publication: added "ex vivo" to the first line of Conclusions in the Abstract.] CLINICAL SIGNIFICANCE: Slower and smaller anastomoses should be anticipated in vivo compared to ex vivo results. Anastomoses with a mod-IL pattern appear clinically advantageous, producing a comparable lumen size in less time than 2 L.

Effects of age, disease and anastomosis on short- and long-term survival after surgical correction of small intestinal strangulating diseases in 89 horses.

BACKGROUND: Although survival rates have been reported after small intestinal surgery for strangulating diseases in horses, none have followed survival for periods relevant to the long lifespan of horses and none have described effect of age, disease and surgical treatments over such long survival periods. OBJECTIVES: To examine effects of age, disease and type of surgery on long-term survival in horses after surgical treatment of small intestinal strangulating diseases over periods relevant to the expected lifespan of a horse. STUDY DESIGN: Retrospective clinical study. METHODS: Post-operative data were gathered from medical records and owner contact for 89 horses with small intestinal strangulation. Survival times from surgery to the date of death or the date of last follow-up were analysed by Kaplan-Meier statistics. Variables of interest were age, type of strangulating disease and surgical correction. Cox proportional hazards regression was used to evaluate these variables. RESULTS: Short-term survival was not affected by any of the variables measured. For long-term survival with Kaplan-Meier statistics, horses ≥16 years old had significantly shorter (P = .002) median survival times (72 months; 95% CI 32.0-96.0) than younger horses (121.7 months; 95% CI 90.0-162), horses without resection had significantly longer (P = .02) survival times (120 months; 95% CI 86-212) than horses that had jejunocecostomy (76.8 months; 95% CI 24-125), and horses with miscellaneous diseases had significantly longer (P = .02) median survival times (161.9 months; 95% CI 72.0-M) than horses with strangulating lipoma (79.8 months; 95% CI 32.0-120.0). In the multivariable Cox Proportional Hazard model, age (HR = 2.67; 1.49-4.75, P < .001) and anastomosis (HR = 0.65; 0.46-0.92, P = .02) had the most significant effect on median survival time. MAIN LIMITATIONS: Limitations were small numbers in some categories, loss of cases to follow-up, owner recall failures and lack of a control group. CONCLUSIONS: The remaining lifespan of older horses at the time of surgery had the greatest effect on survival. Age could influence long-term survival studies after colic surgery, and therefore needs to be considered for survival analyses. Horses that did not require resection and anastomosis had favourable outcomes, underscoring the potential importance of early intervention to reduce the need for resection.

J-incision to approach the cranial abdomen in the adult horse.

OBJECTIVE: To describe a modified celiotomy to improve access to cranial abdominal structures in horses. ANIMALS: Four horses. STUDY DESIGN: Short case series. METHODS: Three horses with gastric impactions were treated with gastrotomies. One horse was treated for a diaphragmatic hernia with herniorrhaphy and mesh augmentation. In all horses, the ventral midline celiotomy was modified cranially with a J-incision through the body wall, along the paracostal arch. RESULTS: The only surgical complications were midline incisional infections in all horses. Three of the four horses had good long-term outcomes; the remaining horse underwent euthanasia for reasons likely unrelated to incisional complications. CONCLUSION: The J-incision improved access to the stomach and diaphragm in these horses. The paracostal component healed in all cases without evidence of infection or dehiscence. CLINICAL SIGNIFICANCE: This modified celiotomy may be considered to improve access during gastrotomy and repair of dorsally located diaphragmatic hernias.

Prevention and Treatment of Postoperative Complications in Equines / Prevención y tratamiento de complicaciones postoperatorias en equinos / Prevenção e tratamento de complicações pós-operatórias em equinos

Abstract Colic surgery is one of the most expensive procedures in equine clinics throughout the world. Although costs of surgery and anesthesia can be standardized to some extent, the cost of aftercare is less predictable. It can be altered considerably by the development of complications, such as surgical site infection, postoperative ileus, and formation of post-operative hernias, among others. Colic surgery places enormous demands on personnel, time, and resources. Nevertheless, it is a life-saving procedure. Complications increase cost through prolonged nursing care, technician salaries, extended treatment with antibiotics and other drugs, repeated laboratory analysis, and high-volume fluid therapy. Additional surgery, such as repeat celiotomy or repair of incisional complications, increases the costs considerably. Because none of these can be anticipated in most cases, a critical part of case management is a complete evaluation of expected and probable unexpected costs for the owner.

Resumen La cirugía de cólicos es uno de los procedimientos más costosos en la clínica de equinos en todo el mundo. Aunque los costos de la cirugía y la anestesia se pueden estandarizar hasta cierta medida, el costo de cuidado posterior es menos predecible y se puede alterar considerablemente mediante el desarrollo de complicaciones, tales como infección del sitio quirúrgico, ileus postoperatorio y formación de hernias postoperatorias, entre otros. La cirugía de cólicos le trae exigencias enormes al personal y requiere tiempo y recursos. Sin embargo, es un procedimiento que salva vidas. Las complicaciones aumentan el costo debido a que el cuidado de enfermería se prolonga, hay que pagar salarios a los técnicos, se amplía el tratamiento con antibióticos y otros medicamentos, hay que repetir análisis de laboratorio y se requiere terapia de fluidos con altos volúmenes. La cirugía adicional, como una celiotomía repetida o reparación de las complicaciones incisionales, aumenta los costos considerablemente. Como ninguno en la mayoría de los casos no se puede prever ninguna de estas cosas, una parte crítica del manejo de casos es la evaluación completa de los costos esperados y los probables no-esperados que cubrirá el propietario.

Resumo A cirurgia de cólica é um dos mais custosos procedimentos clínicas equinas ao redor do mundo. No entanto, os custos de cirurgia e anestesia possam ser padronizados até certo ponto, o custo dos cuidados posteriores é menos previsível e pode se alterar consideravelmente a causa de complicações, tais como infecção do local cirúrgico, íleo pós-operatório e formação de hérnias pós-operatórias, entre outras. A cirurgia de cólica impõe uma enorme demanda de pessoal, tempo e recursos, toda vez que é um procedimento que salva vidas. As complicações aumentam o custo por meio de cuidados prolongados de enfermagem, salários dos técnicos, tratamento prolongado com antibióticos e outros medicamentos, análises laboratoriais repetidas e fluidoterapia de alto volume. Cirurgias adicionais, como repetição de celiotomia ou reparo de complicações incisionais, aumentam consideravelmente os custos. Como nada disso pode ser previsto na maioria dos casos, uma parte crítica do gerenciamento de casos é a avaliação completa dos custos esperados e prováveis inesperados para o proprietário.

Effect of lidocaine on inflammation in equine jejunum subjected to manipulation only and remote to intestinal segments subjected to ischemia.

OBJECTIVE To examine effects of continuous rate infusion of lidocaine on transmural neutrophil infiltration in equine intestine subjected to manipulation only and remote to ischemic intestine. ANIMALS 14 healthy horses. PROCEDURES Ventral midline celiotomy was performed (time 0). Mild ischemia was induced in segments of jejunum and large colon. A 1-m segment of jejunum was manipulated by massaging the jejunal wall 10 times. Horses received lidocaine (n = 7) or saline (0.9% NaCl) solution (7) throughout anesthesia. Biopsy specimens were collected and used to assess tissue injury, neutrophil influx, cyclooxygenase expression, and hypoxia-inducible factor 1α (HIF-1α) expression at 0, 1, and 4 hours after manipulation and ischemia. Transepithelial resistance (TER) and mannitol flux were measured by use of Ussing chambers. RESULTS Lidocaine did not consistently decrease neutrophil infiltration in ischemic, manipulated, or control tissues at 4 hours. Lidocaine significantly reduced circular muscle and overall scores for cyclooxygenase-2 expression in manipulated tissues. Manipulated tissues had significantly less HIF-1α expression at 4 hours than did control tissues. Mucosa from manipulated and control segments obtained at 4 hours had lower TER and greater mannitol flux than did control tissues at 0 hours. Lidocaine did not significantly decrease calprotectin expression. Severity of neutrophil infiltration was similar in control, ischemic, and manipulated tissues at 4 hours. CONCLUSIONS AND CLINICAL RELEVANCE Manipulated jejunum did not have a significantly greater increase in neutrophil infiltration, compared with 4-hour control (nonmanipulated) jejunum remote to sites of manipulation, ischemia, and reperfusion. Lidocaine did not consistently reduce neutrophil infiltration in jejunum.

Response to early repeat celiotomy in horses after a surgical treatment of jejunal strangulation.

OBJECTIVE: To determine the outcome after early repeat celiotomy in horses operated for jejunal strangulation. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 22) that underwent repeat celiotomy for postoperative reflux (POR) and/or postoperative colic (POC) that did not improve within 48 hours from onset after initial surgical treatment of strangulating jejunal lesions by jejunojejunostomy (n = 14) or no resection (n = 8). METHODS: Medical records were reviewed for clinical signs, duration of signs before repeat surgery, surgical findings and treatment, and outcome. Survival was documented by phone call at long-term follow-up. The influence of POC and POR on timing of surgery were analyzed. Long-term survival was examined by Kaplan-Meier analyses. RESULTS: Repeat celiotomy was performed at a median of 57 hours after initial surgery and 16.5 hours from onset of signs, and earlier in horses with POC compared with POR (P < .05). A total of 3/22 horses were euthanatized under anesthesia. A total of 9 of 11 horses with initial jejunojejunostomy required resection of the original anastomosis due to anastomotic complications. In 8 horses without resection, second surgery included resection (4) or decompression (4). Repeat celiotomy was successful in 13/16 horses with POR. Repeat celiotomy eliminated POC in all horses (n = 9). A total of 19 horses were recovered from anesthesia and all survived to discharge. Incisional infections were diagnosed in 13/17 horses where both surgeries were performed through the same ventral median approach, and hernias developed in 4/13 infected incisions. Median survival time was 90 months. CONCLUSION: Repeat celiotomy can eliminate signs of POR and/or POC, and the additional surgery does not appear to aggravate POR. Criteria for repeat celiotomy in this study could provide guidelines for managing POC and POR after surgery for jejunal strangulation.

Effects of experimental mechanical manipulations on local inflammation in the jejunum of horses.

OBJECTIVE: To determine characteristics of the inflammatory reaction in the jejunum of horses in response to various mechanical manipulations. ANIMALS: 12 adult warm blood horses without gastrointestinal tract disorders. PROCEDURES: The proximal aspect of the jejunum in each horse was divided into 5 segments, and the following manipulations were performed: manual emptying, placement of Doyen forceps, enterotomy alone, enterotomy with mucosal abrasion, and serosal abrasion. Jejunum samples were collected before (control), immediately after, and 30 minutes after the end of manipulations and histologically evaluated to determine distribution of neutrophils and eosinophils. RESULTS: Macroscopically, all manipulations resulted in jejunal hemorrhage and edema. Compared with control samples, neutrophil numbers were significantly higher after manipulations in the serosa (after all manipulation types), circular muscle layer (after manual emptying), submucosa (after placement of Doyen forceps), and mucosa (after all manipulations except enterotomy alone). Eosinophil numbers were significantly higher in the submucosa after mechanical abrasion of the serosa and manual emptying versus control samples. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated mechanical manipulation of the jejunum resulted in local inflammatory reactions characterized predominantly by infiltration of neutrophils. This could contribute to the development of postoperative ileus or adhesions in horses without macroscopically detectable injury of the jejunum during surgery.

New ways to diagnose and treat equine dental-related sinus disease.

The diagnosis and treatment of equine dental-related sinus disease is often challenging. Dental-related sinus disease is common and knowledge of these diseases is becoming increasingly important in veterinary medicine. Diagnostic capabilities are continually improving, leading to early diagnostic and therapeutic successes. With advanced imaging modalities, such as computed tomography and magnetic resonance imaging, understanding of the intimate anatomic relationship between teeth and the paranasal sinuses continues to progress. There are many therapeutic options available for the treatment of these common and challenging disorders. A complete understanding of the disease, therapeutic options, and potential complications is vital to overall successful resolution of clinical signs in equine dental-related sinus disorders.

A single caudally based frontonasal bone flap for treatment of bilateral mucocele in the paranasal sinuses of an American miniature horse.

OBJECTIVE: To describe successful surgical treatment of bilateral mucocele in an American Miniature horse using a single bone flap to approach right and left paranasal sinuses simultaneously. STUDY DESIGN: Clinical report. ANIMAL: A castrated 6-year-old American Miniature Horse with a bilateral mucocele of the paranasal sinuses. METHODS: A single bilateral frontonasal sinus flap was used in a standing procedure to access the left and right conchofrontal sinuses simultaneously to remove the mucous contents and to establish permanent drainage into the nasal cavities. RESULTS: The novel procedure used in this horse allowed excellent access to right and left paranasal sinuses simultaneously and completely resolved nasal discharge and difficulty breathing. CONCLUSIONS: A single, bilateral frontonasal sinus flap can be used successfully as a standing procedure to treat bilateral sinonasal disease in horses.

Removal of ureteral calculi in two geldings via a standing flank approach.

CASE DESCRIPTION: Two geldings, aged 11 and 17 years, were examined for treatment of ureteroliths located approximately 10 cm proximal to the bladder. CLINICAL FINDINGS: Ureteral obstruction was an incidental finding in 1 horse that was referred because of urinary tract obstruction and a cystic calculus. This horse did not have clinical or laboratory evidence of renal failure, although severe hydronephrosis was evident on transabdominal ultrasonography. The second patient had a serum creatinine concentration of 6.3 mg/dL (reference range, 0.8 to 2.2 mg/dL) and mild hydronephrosis of the affected left kidney. TREATMENT AND OUTCOME: In both patients, the obstructed ureter was exteriorized through a flank incision as a standing procedure, and the calculus was crushed and removed with a uterine biopsy forceps introduced through a ureterotomy approximately 25 cm proximal to the calculus. The cystic calculus was removed through a perineal urethrostomy by lithotripsy, piecemeal extraction, and lavage. The horse without azotemia developed pyelonephritis in the affected kidney and was euthanatized because of complications of a nephrectomy 13 months later. In the horse with azotemia, the serum creatinine concentration decreased after surgery, and the horse returned to its intended use. However, it was euthanatized approximately 2 years after surgery because of progressive renal failure, and a large nephrolith was found in the previously unobstructed right kidney. CLINICAL RELEVANCE: The technique used for ureterolith removal was successful in both horses in this report, did not require sophisticated equipment, and could be effective in the early stages of ureteral obstruction as a means of restoring urine flow and renal function. The outcome in the horse with advanced unilateral renal disease without azotemia would suggest that nephrectomy should be considered as a treatment in such patients.

The effects of low-level laser therapy in a rat model of intestinal ischemia-reperfusion injury.

BACKGROUND AND OBJECTIVE: To investigate the effects of low-level laser therapy applied to the serosal surface of the rat jejunum following ischemia and reperfusion. MATERIALS AND METHODS: Ninety-six male Sprague-Dawley rats were assigned to 15 groups and anesthetized. Small intestinal ischemia was induced by clamping the superior mesenteric artery for 60 minutes. A laser diode (70 mW, 650 nm) was applied to the serosal surface of the jejunum at a dose of 0.5 J/cm(2) either immediately before or following initiation of reperfusion. Animals were maintained under anesthesia and sacrificed at 0, 1, and 6 hours following reperfusion. Intestinal, lung, and liver samples were evaluated histologically. RESULTS: Intestinal injury was significantly worse (P < 0.0001) in animals treated with laser and no ischemia-reperfusion injury (IRI) compared to sham. Intestinal injury was significantly worse in animals that underwent IRI and laser treatment at all time points compared to sham (P < 0.001). In animals that underwent IRI, those treated with laser had significantly worse intestinal injury compared to those that did not have laser treatment at 0 (P = 0.0104) and 1 (P = 0.0015) hour of reperfusion. After 6 hours of reperfusion there was no significant difference in injury between these two groups. Lung injury was significantly decreased following IRI in laser-treatment groups (P < 0.001). CONCLUSIONS: At the dose and parameters used, low-level laser did not protect against intestinal IRI in the acute phase of injury. However, laser did provide protection against distant organ injury. Failure to observe a therapeutic response in the intestine may be due to inappropriate dosing parameters. Furthermore, the model was designed to detect the histologic response within the first 6 hours of injury, whereas the beneficial effects of laser, if they occur, may not be observed until the later phases of healing. The finding of secondary organ protection is important, as lung injury following IRI is a significant source of morbidity and mortality.

Comparison of surgical and medical treatment of 49 postpartum mares with presumptive or confirmed uterine tears.

OBJECTIVE: To determine outcome after medical or surgical treatment of postpartum mares with confirmed or presumptive uterine tears. STUDY DESIGN: Case series. METHODS: Postpartum mares were included if foaling had occurred within 7 days and uterine tear was confirmed surgically or, in medically treated mares, by palpation or presumed based on peritonitis. Information (age, breed; physical examination, laboratory and abdominocentesis findings; treatment, survival rates, length of hospital stay, treatments costs, and breeding performance after discharge) was obtained from the medical records (1990-2007). The influence of variables was compared between medical and surgical treatment, and between survivors and nonsurvivors. RESULTS: For 49 mares, survival was 75%, with no significant difference between medical (11/15; 73%) or surgical (26/34; 76%) treatment. Admission variables, treatment cost, duration of hospital stay, and likelihood of foaling after discharge were not significantly different between treatment groups. Nonsurvivors were significantly more likely to have gastric reflux, higher heart rate, anion gap, lower total CO(2), and leukocyte count, compared with survivors. Tears were significantly (P=.018) more likely to occur in the right uterine horn than in other parts of the uterus. CONCLUSIONS: Uterine tears occur more commonly in the uterine horns, more so the right horn, and survival is similar with surgical or medical treatment of uterine tears in postpartum mares. CLINICAL RELEVANCE: Medical treatment may be a reasonable alternative to surgical treatment for uterine tears, although the severity of tear that can resolve with medical treatment is unknown, and medical therapy can be as expensive as surgical treatment.

Epidemiologic analysis of nosocomial Salmonella infections in hospitalized horses.

OBJECTIVE: To examine the relationship between abdominal surgery and nosocomial Salmonella infections and the relationship between high caseload in combination with abdominal surgery and nosocomial Salmonella infections in hospitalized horses with signs of gastrointestinal tract disease. ANIMALS: 140 horses. DESIGN: Case-control study. PROCEDURES: To accomplish the first objective, 1 to 4 control horses were matched with each nosocomial case horse on the basis of admission date of a primary case horse. The frequency of abdominal surgery and other investigated exposure factors were compared between nosocomial case horses and control horses. For the second objective, 4 control horses were matched with each nosocomial case horse on the basis of year of admission. The frequency of high caseload (>or=26 inpatients), abdominal surgery, and other factors was compared between nosocomial case horses and control horses. RESULTS: The odds of nosocomial Salmonella infection were 8 times as high (odds ratio=8.2; 95% confidence interval=1.11, 60.24) in horses that underwent abdominal surgery, compared with the odds for horses that did not undergo surgery. High caseload alone or in combination with abdominal surgery was not associated with increased risk of nosocomial Salmonella infection. CONCLUSIONS AND CLINICAL RELEVANCE: Abdominal surgery was identified as a risk factor for nosocomial Salmonella infections in horses. Horses that undergo abdominal surgery require enhanced infection control and preventative care. Risk of nosocomial Salmonella infections may be reduced by implementation of biosecurity measures (such as the use of plastic boots, gloves, and footbaths) immediately after surgery.

Immunohistochemical characterization and quantitative analysis of neurons in the myenteric plexus of the equine intestine.

The present study was performed on whole-mount preparations to investigate the chemical neuroanatomy of the equine myenteric plexus throughout its distribution in the intestinal wall. The objective was to quantify neurons of the myenteric plexus, especially the predominant cholinergic and nitrergic subpopulations. Furthermore, we investigated the distribution of vasoactive intestinal polypeptide and the calcium-binding protein calretinin. Samples from different defined areas of the small intestine and the flexura pelvina were taken from 15 adult horses. After fixation and preparation of the tissue, immunofluorescence labeling was performed on free floating whole-mounts. Additionally, samples used for neuropeptide staining were incubated with colchicine to reveal the neuropeptide distribution within the neuronal soma. The evaluation was routinely accomplished using confocal laser-scanning microscopy. For quantitative and qualitative analysis, the pan-neuronal marker anti-HuC/D was applied in combination with the detection of the marker enzymes for cholinergic neurons and nitrergic nerve cells. Quantitative data revealed that the cholinergic subpopulation is larger than the nitrergic one in several different locations of the small intestine. On the contrary, the nitrergic neurons outnumber the cholinergic neurons in the flexura pelvina of the large colon. Furthermore, ganglia are more numerous in the small intestine compared with the large colon, but ganglion sizes are bigger in the large colon. However, comparison of the entire population of neurons in the different locations of the gut showed no difference. The present study adds further data on the chemoarchitecture of the myenteric plexus which might facilitate the understanding of several gastrointestinal disorders in the horse.