Evaluation of an arthroscopic approach for transection of the equine collateral sesamoidean ligament

Objective: To evaluate: (1) an arthroscopic technique for transection of the collateral sesamoidean ligament (CSL); and (2) the healing response using magnetic resonance (MR) and microscopic examination. Study Design: Experimental study. Animals: Adult horses (n=6). Methods: Six sound horses with normal front foot radiographic and MR examinations were used. Lameness examination was performed before surgery and monthly for 12 months. Front foot radiography was performed at 180 and 360 days after surgery. Front foot MR was performed before, and at 7, 90, 180, and 360 days after surgery. Arthroscopic CSL desmotomy was performed on 1 forelimb. Gross and microscopic examination was performed on the CSL from both forelimbs at 360 days after surgery. Lameness scores were compared over time using the nonparametric Friedman's test for paired groups. CSL measurements were compared using paired t‐tests with a 2‐tailed significance level of P<.05. Results: Radiographs remained normal throughout study period. Surgery resulted in lameness on the operated limb for up to 2 months, after which all horses returned to soundness. CSL transection was confirmed during arthroscopy and with MR examination 7 days after surgery. Gross and microscopic evaluation confirmed ligament healing. Conclusions: CSL desmotomy resulted in short‐term lameness after surgery followed by healing of the CSL confirmed by gross and microscopic analysis.     

ENDOSCOPIC ULTRASOUND INSTRUMENTATION, APPLICATIONS IN HUMANS, AND POTENTIAL VETERINARY APPLICATIONS

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.     

Serologic responses of dogs given a commercial vaccine against Leptospira interrogans serovar pomona and Leptospira kirschneri serovar grippotyphosa

OBJECTIVE: To evaluate serum titers obtained by use of the microscopic agglutination test (ie, MAT titers) to Leptospira interrogans serovar pomona and autumnalis and Leptospira kirschneri serovar grippotyphosa in dogs given a commercial vaccine against serovars pomona and grippotyphosa. ANIMALS: Forty 12-week-old puppies and 20 mature Beagles. PROCEDURE: Puppies received a commercial vaccine against serovars pomona and grippotyphosa at 12 weeks of age, then received a booster vaccine and 3 weeks later; mature dogs received the vaccine once. Serum MAT titers to serovars pomona, autumnalis, and grippotyphosa were measured before vaccination and at 2, 4, 6, 10, and 16 weeks after the first or only vaccination. RESULTS: Of the 40 puppies vaccinated, 40, 0, and 40 developed MAT titers of > 100 after vaccination to serovars pomona, grippotyphosa, and autumnalis, respectively. Microscopic agglutination test titers to serovar autumnalis were higher than MAT titers to serovars pomona and grippotyphosa and persisted in some dogs for 16 weeks (6 weeks longer than for titers to serovar pomona). Of the 20 mature dogs, 13, 5, and 20 developed MAT titers of > 100 at 2 weeks to serovars pomona, grippotyphosa, and autumnalis, respectively. Titers to serovar pomona were higher and persisted in some dogs beyond 16 weeks after vaccination, compared with titers to serovars pomona and grippotyphosa, which persisted for 10 and 6 weeks, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Subunit vaccines against serovars pomona and grippotyphosa induce MAT titers not only to homologous antigens but also to serovar autumnalis, which could lead to a misdiagnosis of leptospirosis caused by serovar autumnalis.     

Toxic shock syndrome in a horse with Staphylococcus aureus pneumonia

A 3-year-old Thoroughbred gelding was examined because of clinical signs of pneumonia and shock. Mucous membrane petechiation and ventral edema were observed and considered to be a result of vasculitis. Epidermal necrosis developed on the distal portions of the limbs. The horse had a persistent high fever that was unresponsive to nonsteroidal anti-inflammatory treatment, and Staphylococcus aureus was isolated from a nasal swab specimen and 2 transtracheal wash fluid samples. Antimicrobial, anti-inflammatory, and supportive treatment resulted in clinical improvement. However, resolution of the pulmonary infection required long-term (42 days) antimicrobial administration. Staphylococcus aureus strains isolated from this horse were positive for the toxic shock syndrome toxin-1 gene and were shown to produce toxic shock syndrome toxin-1, the causative factor in toxic shock syndrome in humans. The horse's clinical signs were attributed to toxic shock syndrome secondary to pulmonary S. aureus infection.     

Measurements of the acid-binding capacity of ingredients used in pig diets

: Some feed ingredients bind more acid in the stomach than others and for this reason may be best omitted from pig starter foods if gastric acidity is to be promoted. The objective of this study was to measure the acid-binding capacity (ABC) of ingredients commonly used in pig starter foods. Ingredients were categorised as follows: (i) milk products (n = 6), (ii) cereals (n = 10), (iii) root and pulp products (n = 5), (iv) vegetable proteins (n = 11), (v) meat and fish meal (n = 2), (vi) medication (n = 3), (vii) amino acids (n = 4), (viii) minerals (n = 16), (ix) acid salts (n = 4), (x) acids (n = 10). A 0.5 g sample of food was suspended in 50 ml distilled de-ionised water with continuous stirring. This suspension was titrated with 0.1 mol/L HCl or 0.1 mol/L NaOH so that approximately 10 additions of titrant was required to reach pH 3.0. The pH readings after each addition were recorded following equilibration for three minutes. ABC was calculated as the amount of acid in milliequivalents (meq) required to lower the pH of 1 kg food to (a) pH 4.0 (ABC-4) and (b) pH 3.0 (ABC-3). Categories of food had significantly different (P < 0.01) ABC values. Mean ABC-4 and ABC-3 values of the ten categories were: (i) 623 (s.d. 367.0) and 936 (s.d. 460.2), (ii) 142 (s.d. 79.2) and 324 (s.d. 146.4), (iii) 368 (s.d. 65.3) and 804 (s.d. 126.7), (iv) 381 (s.d. 186.1) and 746 (s.d. 227.0), (v) 749 (s.d. 211.6) and 1508 (s.d. 360.8), (vi) 120 (s.d. 95.6) and 261 (s.d. 163.2), (vii) 177 (s.d. 60.7) and 1078 (s.d. 359.0), (viii) 5064 (s.d. 5525.1) and 7051 (s.d. 5911.6), (ix) 5057 (s.d. 1336.6) and 8945 (s.d. 2654.1) and (x) -5883 (s.d. 4220.5) and -2591 (s.d. 2245.4) meq HCl per kg, respectively. Within category, ABC-3 and ABC- 4 values were highly correlated: R2 values of 0.80 and greater for food categories i, iv, v, vi, vii and viii. The correlation between predicted and observed ABC values of 34 mixed diets was 0.83 for ABC-4 and 0.71 for ABC-3. It was concluded that complete diets with low ABC values may be formulated through careful selection of ingredients. The final pH to which ABC is measured should matter little as ABC-3 and ABC-4 are highly correlated.     

Surgical treatment and radiation therapy of frontal lobe meningiomas in 7 dogs

The cases of 7 adult dogs with generalized seizures managed by surgical excision and radiation therapy for frontal lobe meningiomas were reviewed. The neurological examination was unremarkable in 6 of the 7 dogs. Five dogs were operated on using a bilateral transfrontal sinus approach and 2 using a unilateral sinotemporal approach to the frontal lobe. One dog was euthanized 14 d after surgery; radiation therapy was initiated 3 wk after surgery in the remaining 6 dogs. Long-term follow-up consisted of neurological examination and magnetic resonance imaging (MRI) and/or computed tomography (CT) scan after radiation therapy. The mean survival time for dogs that had surgery and radiation therapy was 18 mo after surgery. Frontal lobe meningiomas have been associated with poor prognosis. However, the surgical approaches used in these cases, combined with radiation therapy, allow a survival rate for frontal lobe meningiomas similar to that for meningiomas located over the cerebral convexities.     

Measuring Eastern Redcedar (Juniperus virginiana L.) Mass With the Use of Satellite Imagery

Eastern redcedar (Juniperus virginiana L.) is an aggressively spreading native species in Oklahoma grasslands. It decreases rangeland forage production, and has been implicated in reducing stream flow and groundwater recharge. Industrial-scale plans to use redcedar as a biofuel source are being considered. Optimal placement of redcedar-based industries requires determination of redcedar availability. Such large-area inventories of redcedar mass can be practically addressed via aircraft or satellite remote sensing. Therefore, we conducted a study in central and western Oklahoma to develop and test a remote-sensing–based allometric equation relating redcedar canopy area to aboveground dry mass (AGM). We used automated methods to measure tree canopy area from georectified, pan-sharpened, multispectral QuickBird images having a spatial resolution of 0. 45 m² per pixel ground sample area. We also measured the canopy area and fresh and dry mass of these trees with the use of destructive sampling techniques. Regression analysis showed that satellite-derived measurements of canopy coverage explained about 85% of field-measured redcedar dry AGM in the study plots. The resulting allometric equation was applied to an independent data set, yielding dry AGM of 38.2 metric tons ? ha^?1, which was well within the field-measured range of 36–43 metric tons ? ha^?1. The allometric equation was then applied to Natural Resources Conservation Service measurements of redcedar canopy coverage for 17 counties in Oklahoma, to determine that the area of interest contains a median value of about 11.5 million metric tons of redcedar AGM. These results indicate that 0.45-m² spatial resolution multispectral imagery can be a useful tool for rapid and reliable measurement of redcedar dry AGM.     

VARIATIONS IN MAGNETIC RESONANCE VENOGRAPHIC ANATOMY OF THE DORSAL DURAL VENOUS SINUS SYSTEM IN 51 DOGS

Variations in intracranial dural venous sinus anatomy have been widely reported in humans, but there have been no studies reporting this in dogs. The purpose of this retrospective study was to describe variations in magnetic resonance (MR) venographic anatomy of the dorsal dural venous sinus system in a sample population of dogs with structurally normal brains. Medical records were searched for dogs with complete phase contrast, intracranial MR venograms and a diagnosis of idiopathic epilepsy. Magnetic resonance venograms were retrieved for each dog and characteristics of the dorsal dural sinuses, symmetry of the transverse sinuses and other anatomic variations were recorded. A total of 51 dogs were included. Transverse sinus asymmetry was present in 58.8% of the dogs, with transverse sinus hypoplasia seen in 39.2%, and aplasia in 23.5% of dogs. For 70.6% of dogs, at least one anatomic variation in the dorsal sagittal sinus was observed, including deviation from the midline (33.3%) and collateral branches from either the dorsal sagittal sinus or dorsal cerebral veins (54.9%). In 5 dogs (9.8%) a vessel was also identified running from the proximal transverse sinus to the distal sigmoid sinus, in a similar location to the occipital sinus previously reported in children. Findings from this study indicated that, as in humans, anatomic variations are common in the intracranial dural venous sinus system of dogs. These anatomic variations should be taken into consideration for surgical planning or diagnosis of cerebrovascular disease.     

CANINE BRAIN ANATOMY ON MAGNETIC RESONANCE IMAGES

Magnetic resonance (MR) images of the canine brain were acquired during investigation of dogs with neurologic disease. A paramagnetic contrast medium was used for enhancement. MR provided images with excellent contrast between grey and white matter, as well as brain tissue and cerebrospinal fluid. Good resolution and anatomic detail of the canine brain were obtained. A series of images was compiled and labelled as a reference for MR anatomy of the canine brain.     

The effects of cooling and vitrification of embryos from mares treated with equine follicle-stimulating hormone on pregnancy rates after nonsurgical transfer

Equine embryos can remain viable for 12 to 24 hours when cooled and stored at 5°C.¹ Cryopreservation of embryos would allow for long-term preservation of genetic material and more efficient management of embryo recipients. This study compared pregnancy rates after transfer of equine embryos vitrified within 1 hour of collection or cooled for 12 to 19 hours before vitrification. Mares (N = 40) were superovulated using equine follicle-stimulating hormone (eFSH). Embryos were recovered 6.5 days after ovulation or 8 days after human chorionic gonadotropin. Forty morulae or early blastocysts with a grade of 1 to 2 and <300 mm in diameter were randomly assigned to 1 of 2 treatments: Group 1 (n = 20), washed 4 times in a commercial holding medium and then vitrified; Group 2 (n = 20), washed 3 times and then stored in the same holding medium at 5°C to 8°C in a passive cooling device for 12 to 19 hours before being vitrified. To thaw, embryos were warmed by holding the straw in air at room temperature for 10 seconds and then submerged in a water bath (20°C to 22°C) for an additional 10 seconds. The contents of the straw were transferred directly into a recipient that had ovulated 4 to 6 days previously. There were no differences (P > .05) in embryo diameter, grade, or morphology score between treatment groups before vitrification. Pregnancy rates (day 16) were not different (P > .05) between embryos vitrified immediately after collection (15 of 20; 75%) and embryos cooled for 12 to 19 hours before vitrification (13 of 20; 65%). Based on these results, small equine embryos (<300 mm) can be stored at 5°C to 8°C for 12 to 19 hours before vitrification without a significant loss of viability.