The polarity protein Par-3 directly interacts with p75NTR to regulate myelination

Cell polarity is critical in various cellular processes ranging from cell migration to asymmetric cell division and axon and dendrite specification. Similarly, myelination by Schwann cells is polarized, but the mechanisms involved remain unclear. Here, we show that the polarity protein Par-3 localizes asymmetrically in Schwann cells at the axon-glial junction and that disruption of Par-3 localization, by overexpression and knockdown, inhibits myelination. Additionally, we show that Par-3 directly associates and recruits the p75 neurotrophin receptor to the axon-glial junction, forming a complex necessary for myelination. Together, these results point to a critical role in the establishment of cell polarity for myelination.     

Systemic granulomatous disease and sialometaplasia in a dog with Bartonella infection

Systemic granulomatous disease involving the spleen, heart, lymph nodes, omentum, liver, kidney, lung, mediastinum, and salivary glands developed in an 8-year-old Rottweiler. The dog also had sialometaplasia of both submandibular salivary glands. Bartonella henselae and B. vinsonii subsp. berkhoffii DNA was amplified from the salivary gland by polymerase chain reaction analysis. Bartonellae may be the cause of this systemic disease, but to the authors' knowledge, involvement of omentum, mediastinum, and salivary glands has not previously been reported in association with Bartonella infection. Bartonellae should be considered potential causes of sialometaplasia.     

Development of allometric leaf area models for intensively managed black walnut (Juglans nigra L.)

? Introduction

Intensive plantation management of high-value hardwoods, such as black walnut (Juglans nigra L.), is focused on maximizing both stem form and growth at the stand and tree level. While significant research has focused on genetic improvement in black walnut, little is known about the production ecology of this species in plantation settings.

? Objectives

The aim of this study is to assess the applicability of nondestructive projected leaf area (PLA) estimation based on the pipe model theory in three single-aged J. nigra plantations representing discrete age classes ranging from 3 to 27?years of age.

? Results

Branch-level PLA was modeled as a function of branch basal cross-sectional area (R ²?=?0.875). Six nondestructive tree-level PLA models were assessed, with four models yielding R ²?>?0.90. Tree-level models performed well across age classes, with model fits comparable to previous studies in coniferous species.

? Conclusion

This study demonstrates that allometric approaches to modeling leaf area distribution in hardwoods are feasible, but future efforts may need to use different sampling approaches and/or quantify variables that have not been significant in conifers. This study represents an important first step into more quantitative analysis of production ecology of deciduous species in the CHFR of the USA.     

Sensitivity and specificity of radiography for detection of elbow incongruity in clinical patients

Elbow incongruity is an important factor regarding the treatment and prognosis of elbow dysplasia. Our purpose was to determine the sensitivity and specificity for radiographic detection of elbow incongruity in clinical patients, to establish inter- and intraobserver variation for different parameters, and to evaluate the possibility of radiographic grading of incongruity. Standard radiographic projections were acquired from 29 incongruent and nine congruent elbows of dogs of various ages and breeds. Computed tomography (CT) was used to diagnose and grade the incongruity. All radiographs were evaluated by four observers for detection and grading of elbow incongruity. Sensitivity, specificity, inter- and intraobserver variability were calculated. The mean sensitivity for detection of incongruity was very good (88.8%) with a mean specificity of 91.7%. Correct grading of incongruity was difficult. The radioulnar step and the widening of the humeroulnar and humeroradial joint space were seen most frequently. Intraobserver and interobserver variability were fair to excellent (Kappa = 0.372-0.809), depending on the investigated parameters. Radiography is valuable to screen for elbow incongruity. In over 91% of the patients, a clear distinction could be made between a congruent and an incongruent joint grading was not possible.     

Stomach wall evaluation using helical hydro-computed tomography

In helical hydro-computed tomography (helical hydro-CT), water is used as a neutral luminal contrast medium together with intravenous iodine contrast medium for the diagnosis and staging of human gastric neoplasia. We evaluated the feasibility of helical hydro-CT in 11 healthy animals (nine dogs and two cats). Adequate uniform gastric distension was obtained with 30 ml water/kg body weight. Fourteen client-owned dogs and four cats with suspected or diagnosed gastric neoplasia then underwent helical hydro-CT followed by intravenous contrast medium administration. Focal thickening with moderate contrast enhancement was found in 10 dogs and 3 cats. The extent of the lesion was assessed easily in all these patients. Three dogs and one cat had a normal stomach wall. One dog had multifocal thickening of the antrum but no histopathologic diagnosis was made. Helical hydro-CT, followed by intravenous contrast medium administration, is a simple technique for assessing the stomach wall.     

What is your diagnosis? Shoulder mass in a dog with lameness

Abstract: An adult castrated male Golden Retriever of unknown age was presented with a history of weight loss and progressive left thoracic limb lameness. On physical examination, a solid mass was palpated on the left scapula that had areas of lysis on radiographs and an area of cortical bone loss on ultrasound. Hepatomegaly, abdominal distension, and numerous intra‐abdominal soft tissue masses were also found. Fine‐needle aspirates of the scapula and several abdominal masses contained numerous free nuclei mixed with fewer individualized, intact cells that were round in shape and rarely formed small sheets. The cells had high nuclear to cytoplasmic ratios, central nuclei, coarsely stippled chromatin, 1–2 prominent nucleoli, and basophilic cytoplasm with indistinct cell borders. The cytopathologic interpretation was neuroendocrine neoplasia, either metastatic or multicentric. The dog was subsequently euthanized and based on gross and histologic findings at necropsy, a diagnosis of pheochromocytoma with multiple metastases was made. The neoplastic cells stained positive with Grimelius stain and were immunoreactive for synaptophysin and chromogranin A. Pheochromocytomas are rare tumors in dogs and uncommonly undergo distant metastasis, especially to bone.     

Arthroscopic visualisation of the third metacarpal and metatarsal condyles in the horse

Reasons for performing study: Arthroscopy of the fetlock joints is a routine surgical procedure in the horse. It is unclear how much of the articular surface of the condyles of the metacarpal (MCIII)/metatarsal (MTIII) bone can be visualised using either the dorsal or palmar/plantar arthroscopic approach. Objectives: To investigate which part of the articular surface of the MCIII/MTIII condyles of the fetlock joints can be evaluated arthroscopically using: 1) dorsal approach in combination with flexion; 2) standard palmar/plantar approach; or 3) additional portal at the base of the sesamoid bone with joint extension. Methods: All 3 arthroscopic approaches were performed on 20 fore‐ and 20 hindlimbs of 14 cadavers. For each approach, a curette was inserted ipsilaterally to create a lesion at the most distal part of the condyle that could be seen. After disarticulation and placement of a nail in each lesion, the maximally reachable angle was calculated on a perfect lateromedial radiograph. The 0° angle was determined as the distal crossing of the best fitting circle around the condyle with a line parallel to the dorsal MCIII/MTIII bone running through the circle centre (positive angle dorsal to 0°, negative palmar/plantar to 0°). Results: Using the dorsal approach with flexion, a significantly larger area of visualisation was present in the hind‐ (?23.4°) compared to the forelimb (+2.7°). Using the palmar/plantar approach (fore: ?60.4°; hind: ?70.7°) and the approach at the base of the sesamoid bone (fore: ?36.3°; hind: ?47.6°) more cartilage could be seen in the fore‐ compared to the hindlimb. When combining the 3 approaches, the remaining nonvisible part measured 38.9° in the fore‐ and 24.2° in the hindlimb, both located palmaro/plantarodistally. Conclusions: The use of dorsal and palmar/plantar arthroscopic approaches in combination with flexion and extension of the fetlock joint allows visualisation of the majority of the cartilage of the MCIII/MTIII condyles. The nonvisible section is smaller in the hindlimb compared to the forelimb. Potential relevance: Knowledge of the specific areas of visualisation of the condyles on arthroscopy is important for both diagnostic and therapeutic planning of fetlock disorders.     

Idiopathic Eosinophilic Masses of the Gastrointestinal Tract in Dogs

Background: Eosinophilic inflammation of the gastrointestinal tract of dogs occurs in numerous disorders, typically resulting in diffuse intestinal thickening. Rarely, eosinophilic masses have been reported.
Objective: Describe a series of dogs with 1 or more idiopathic eosinophilic gastrointestinal masses (IEGM) to better characterize the clinical features, treatment, and prognosis.
Animals: Seven dogs with 1 or more gastrointestinal masses composed primarily of eosinophilic infiltrates for which no underlying cause was found.
Methods: Retrospective case series.
Results: Rottweilers and purebred, large breed dogs predominated. Dogs were middle-aged and typically had chronic signs of upper or lower gastrointestinal disease. Decreased appetite, vomiting, and evidence of gastrointestinal hemorrhage were present in the majority of cases. An abdominal or rectal mass was frequently noted on physical examination. Common laboratory abnormalities included peripheral eosinophilia, mature neutrophilia, hypoproteinemia, and hypocholesterolemia. The masses were histologically composed of moderate to severe eosinophilic infiltrates, which were often transmural and accompanied by fibrosis. All dogs treated with surgery alone died of complications of their disease. Treatment with corticosteroids and ivermectin improved clinical signs, caused resolution of eosinophilic infiltrates, and prolonged survival in most dogs treated medically.
Conclusions and Clinical Importance: These findings suggest that the prognosis for dogs with IEGM may be good when recognized and managed appropriately. When surgery is performed, medical treatment should also be added.     

Transcatheter Atrial Septal Defect Closure with the AMPLATZER® Atrial Septal Occluder in 13 Dogs: Short- and Mid-Term Outcome

Background: Transcatheter atrial septal defect (ASD) closure in the dog was first reported in 2005.
Objectives: Describe the technique and both short- and mid-term outcome of transcatheter ASD closure with the Amplatzer^® atrial septal occluder (ASO).
Animals: Thirteen client-owned dogs with ASD.
Methods: Records of the initial 13 dogs in which transcatheter ASD closure was attempted at Texas A&M University were reviewed.
Results: All dogs had hemodynamically relevant septum secundum ASD. Two dogs had concurrent congenital abnormalities. ASOs were deployed in 13 dogs and released in 12. Eleven were released by a right jugular approach and 1 by a transatrial approach through a right lateral thoracotomy. Transthoracic echocardiographic estimates of ASD size were 14.0 ± 5.4 mm (mean ± 1 standard deviation) with a range of 7–22 mm. Accidental right atrial release occurred in 1 dog and embolization after release occurred in 2 dogs. Transcatheter ASD closure was successful in 10 dogs. Transthoracic color Doppler echocardiography the day after ASD closure indicated complete occlusion in 5 dogs, trivial to mild residual shunting in 4 dogs, and moderate residual shunting in 1 dog. Follow-up echocardiograms (mean of 12.4 ± 7.4 months postprocedure) were available for 9 dogs. There was no residual ASD shunting in 6 dogs. In 3 of the 5 dogs with postoperative residual shunting it was judged to be decreased and hemodynamically unimportant relative to the dogs' postoperative evaluations. The mean length of event-free survival in the 10 dogs that underwent successful transcatheter ASD closure was 22.2 ± 10.2 months.