INCOMPLETE OSSIFICATION OF THE HUMERAL CONDYLE IN VIETNAMESE POT-BELLIED PIGS

The purpose of this study was to evaluate the occurrence of humeral condylar fractures in Vietnamese pot-bellied pigs and to postulate a possible predisposing cause for these fractures. Thirteen Vietnamese pot-bellied pigs (Group A) were evaluated over an eight year period (1990-1998), each with a history of either a unilateral or bilateral forelimb lameness. The cause of lameness was localized to the elbow region. Of the thirteen pigs, twenty-one elbows were evaluated radiographically. Pigs ranged in age from six months to four years old. All pigs over the age of seven months showed radiographic evidence of elbow degenerative joint disease. Fractures involving the medial aspect of the humeral condyle were identified in 8/21 studies (38%). A well-defined linear intracondylar articular lucency was identified in 7/21 studies (33%) on the craniocaudal projection. The site of this lucency corresponded to the location of the articular component of the fractures seen involving the humeral condyle. The elbows of five pot-bellied pigs with no known history of forelimb lameness or trauma (Group B) were evaluated radiographically following euthanasia. All five pigs were of unknown age and gender. An intracondylar vertical linear lucency was identified bilaterally in three pigs (60%). Concurrent degenerative joint disease was present in all instances. The remaining two pigs were radiographically normal. Computed tomography of the elbows was performed in one affected pig from Group B. The radiographic findings in this pig were verified. Histopathology of the right elbow of this affected pig was diagnostic for incomplete endochondral ossification of the humeral condyle. A similar condition involving the humeral condyle has been previously described in Cocker and Brittany Spaniels. These canine breeds also have a high incidence of humeral condylar fractures. It is postulated that Vietnamese pot-bellied pigs are similarly prone to humeral condylar fractures, even in the absence of known trauma, due to incomplete ossification of the humeral condyle.     

Multiple organ dysfunction syndrome in humans and dogs

Objective: To describe the clinical appearance and theories on the pathogenesis of multiple organ dysfunction syndrome (MODS) in humans, and to review the evidence suggesting that a similar syndrome occurs in critically ill dogs. Human‐based studies: Currently, there are a multitude of publications describing the pathogenesis and clinical course of MODS in humans. Providing much of the basis for on‐going research and the development of clinical applications, a consensus statement made by the American College of Chest Physicians and Society of Critical Care Medicine defined parameters that had guided and shaped much of what is known about MODS. Veterinary‐based studies: To date, there are few publications describing MODS in dogs and much of what is known has been derived from case reports and reviews of various critical illnesses in dogs. While a similar syndrome of multiple organ dysfunction likely exists in dogs, a consensus statement defining clinical parameters has not been made. Data sources: Veterinary and human literature review. Conclusions: The development of MODS in human critical illness is widely recognized and major strides have been made in the understanding of this complex syndrome. Scoring schemes applied to human MODS patients have established that with increasing numbers of failing organs, there is a worse prognosis. As a similar finding likely exists in dogs, an awareness of MODS is vital to veterinary critical care clinicians and a consensus definition of MODS in dogs is warranted.     

Use of quantitative two-dimensional color tissue Doppler imaging for assessment of left ventricular radial and longitudinal myocardial velocities in dogs

OBJECTIVE: To determine left ventricular free wall (LVFW) radial and longitudinal myocardial contraction velocities in healthy dogs via quantitative 2-dimensional color tissue Doppler imaging (TDI). ANIMALS: 100 dogs. PROCEDURE: TDI was used by a single trained observer to measure radial and longitudinal myocardial movement in the LVFW. Radial myocardial velocities were recorded in segments in the endocardial and epicardial layers of the LVFW, and longitudinal velocities were recorded in segments at 3 levels (basal, middle, apical) of the LVFW. RESULTS: LVFW velocities were higher in the endocardial layers than in the epicardial layers. Left ventricular free wall velocities were higher in the basal segments than in the middle and apical segments. Radial myocardial velocity gradients, defined as the difference between endocardial and epicardial velocities, were (mean +/- SD) 2.5 +/- 0.8 cm/s, 3.8 +/- 1.5 cm/s, and 2.3 +/- 0.9 cm/s in systole, early diastole, and late diastole, respectively. Longitudinal myocardial velocity gradients, defined as the difference between basal and apical velocities, were 5.9 +/- 2.2 cm/s, 6.9 +/- 2.5 cm/s, and 4.9 +/- 1.7 cm/s in systole, early diastole, and late diastole, respectively. A breed effect was detected for several systolic and diastolic TDI variables. In all segments, systolic velocities were independent of fractional shortening. CONCLUSIONS AND CLINICAL RELEVANCE: LVFW myocardial velocities decreased from the endocardium to the epicardium and from base to apex, thus revealing intramyocardial radial and longitudinal velocity gradients. These indices could enhance conventional echocardiographic analysis of left ventricular function in dogs. Breed-specific reference intervals should be defined.     

Toxicity, dosage, and efficacy of vinorelbine (Navelbine) in dogs with spontaneous neoplasia

The purpose of this study was to evaluate short-term adverse effects and determine a safe dosage for vinorelbine (Navelbine)--a new semisynthetic vinca alkaloid--in dogs with malignant tumors. Nineteen dogs were treated with vinorelbine as a 5-minute IV infusion every 7 days at starting dosages ranging from 10 to 20 mg/m2. The median number of treatments per dog was 7 (range, 1-11). The maximum tolerated dosage varied between 15 and 18 mg/m2, and a starting dosage of 15 mg/m2 is recommended. Neutropenia was the dose-limiting toxicity. Although efficacy was a secondary endpoint of this dosage-finding study, 2 dogs with metastatic bronchoalveolar carcinoma experienced a partial response for an overall response rate of 12.5% in 16 dogs with gross measurable disease. Three dogs with microscopic disease were treated (incompletely excised bronchoalveolar carcinoma or lymph node metastatic disease). Two died of pulmonary metastatic disease 113 and 196 days posttreatment, and 1 is still alive after at least 730 days. The well-tolerated toxicity profile and clinical activity observed in dogs with bronchoalveolar carcinoma warrants further investigation.     

Features of follicular dendritic cells in ovine pharyngeal tonsil: an in vivo and in vitro study in the context of scrapie pathogenesis

Although the alimentary tract has been suggested as the most likely portal of entry in natural scrapie, a growing amount of data indicates that the respiratory system and more specifically the pharyngeal tonsils serve as a natural portal of entry for scrapie. This study describes for the first time the broad cell populations in the lymphoid compartment of pharyngeal tonsils and more specifically inside the lymphoid follicles where the scrapie agent accumulates during the period of latency. Follicular dendritic cells (FDCs), stromal cells located in the light zone of the germinal centre of lymphoid follicles, seem to be the principal causal factor in the accumulation of the infectious agent in transmissible spongiform encephalopathy (TSE) diseases. Knowing that efficient lymphoreticular prion propagation requires PrPc expression, we analysed the expression of PrPc with the mouse monoclonal antibody Pri 909 both in situ and on FDC-cluster-enriched cell suspensions. In situ, a positive staining was observed in the germinal centre of pharyngeal lymph follicles. The germinal centre labelling was due to the presence of a follicular dendritic network as revealed after immunogold staining of isolated FDC clusters. Our results suggest that the pharyngeal lymphoreticular system and more specifically PrPc expressing follicular dendritic cells could serve as a prion "reservoir" during the latency phase, thus playing a key role during the scrapie lymphoinvasion.     

ULTRASOUND-GUIDED FINE-NEEDLE ASPIRATION BIOPSY OF BONE LESIONS: A PRELIMINARY REPORT

The purpose of this preliminary study was to determine the feasibility of ultrasound-guided fine-needle aspiration biopsy of suspected neoplastic lesions of bone. Ultrasound-guided fine-needle aspiration biopsy samples were obtained in 23 patients (22 dogs and one cat) with radiographic evidence of a destructive or destructive/productive bone lesion. The lesions were located in the appendicular skeleton in 20 patients and in the axial skeleton in three. Histopathology from tissue core biopsies and/or necropsy was not deemed necessary in 11 patients where ultrasound-guided fine-needle aspiration biopsy results were conclusive for neoplasia. A cytologic diagnosis from ultrasound-guided fine-needle aspiration biopsy was confirmed by histologic samples obtained at surgery or necropsy in five patients. In one of these five, ultrasound-guided fine-needle aspiration biopsy samples were diagnostic for sarcoma when tissue-core biopsy was inconclusive. Both ultrasound-guided fine-needle aspiration biopsy and tissue core biopsy techniques were inconclusive in one patient. Ultrasound-guided fine-needle aspiration biopsy samples were nondiagnostic in five patients where a follow-up histopathologic diagnosis of neoplasia was made. It was concluded that ultrasound-guided fine-needle aspiration biopsy of bone, if diagnostic, may help avoid the need for a tissue-core biopsy in some instances. However, a negative ultrasound-guided fine-needle aspiration biopsy sample does not rule out neoplasia. A negative ultrasound-guided fine-needle aspiration biopsy should be followed by a tissue-core biopsy and histologic analysis in all patients. Ultrasound-guided fine-needle aspiration biopsy seems to be a promising technique for the diagnosis of bone lesions.     

Persistent dorsal displacement of the soft palate attributable to a frenulum of the epiglottis in a racing Thoroughbred

CASE DESCRIPTION: A 7-year-old sexually intact male Thoroughbred racehorse was evaluated because of exercise intolerance, respiratory tract noise, and coughing when eating. CLINICAL FINDINGS: A persistent dorsal displacement of the soft palate was identified during endoscopic examination of the upper portions of the respiratory tract. Radiography of the pharyngeal and laryngeal regions revealed a hypoplastic epiglottis that was ventral to, and not in contact with, the soft palate. The horse was anesthetized, and an oral endoscopic examination revealed a subepiglottic frenulum that had resulted in the dorsal displacement of the soft palate. TREATMENT AND OUTCOME: The frenulum was transected transendoscopically by use of a diode laser. Twenty-four hours following surgery, repeat endoscopic and radiographic examinations revealed that the epiglottis had returned to its correct anatomic position in relation to the soft palate. Four weeks after surgery, endoscopy of the upper portions of the airway revealed recurrence of the dorsal displacement of the soft palate. CLINICAL RELEVANCE: A subepiglottic frenulum should be considered as a cause of persistent dorsal displacement of the soft palate in horses. An endoscopic examination of the oropharyngeal region should be performed in horses prior to undertaking any surgical interventions to treat persistent dorsal displacement of the soft palate.     

COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE NORMAL CANINE STIFLE

Computed tomographic (CT) imaging of eight normal cadaveric canine stifles was performed before and after intra-articular administration of iodinated contrast medium. Transverse CT images were reconstructed in dorsal, parasagittal, and oblique planes. The following ligamentous structures were identified on transverse CT images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, and the medial and lateral collateral ligaments. The following ligamentous structures were identified on transverse computed tomographic arthrography (CTA) images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, meniscofemoral ligament, cranial meniscotibial ligaments, caudal meniscotibial ligaments, intermeniscal (transverse) ligament, and the medial and lateral collateral ligaments. The patellar tendon was identified on transverse and reconstructed dorsal and sagittal CT and CTA images in all stifles. Multiplanar reconstructions enabled further evaluation of the continuity of the cranial and caudal cruciate ligaments and menisci. The medial and lateral collateral ligaments were not clearly identified on CT or CTA multiplanar reconstructed images.     

Assessment of neutrophil function in canine cancer patients undergoing chemotherapy and correlation with neutrophil numbers

Decreased neutrophil function following administration of chemotherapy has been reported in dogs with lymphoma. The first objective of our study was to determine if neutrophil oxidative burst and phagocytic activity are affected by chemotherapy 7 to 10 days following initiation of treatment in dogs with lymphoma and non-lymphoma malignancies. The second objective was to determine if there is a correlation between neutrophil numbers and neutrophil function before or after initiation of chemotherapy. Flow cytometric assessment of neutrophil oxidative burst and phagocytosis following stimulation with Escherichia coli was performed in 9 dogs diagnosed with lymphoma and 17 non-lymphoma tumor-bearing dogs pre- and post-chemotherapy, as well as 14 tumor-free control dogs. Spearman rank correlation was performed to determine if blood neutrophil numbers and neutrophil function were significantly correlated. Lymphoma patients showed significantly reduced percentage neutrophil oxidative burst post-chemotherapy compared to healthy controls as well as compared to pre-chemotherapy values (P = 0.0022 and P = 0.0020, respectively). Lymphoma patients also exhibited significantly reduced neutrophil phagocytosis activity post-chemotherapy compared to controls and pre-chemotherapy values (P = 0.0016 and P = 0.014, respectively). Dogs with non-lymphoma malignancies also showed a significant decrease in both percentage oxidative burst and phagocytosis post-chemotherapy compared to pre-chemotherapy values (P = 0.00040 and P = 0.029, respectively). Neutrophil numbers and function were not significantly correlated. The results of the study suggest that chemotherapeutic treatment decreases neutrophil oxidative burst and phagocytic activity 7 to 10 days post-treatment in dogs with various malignancies. Furthermore, neutrophil numbers cannot be used to predict neutrophil function.     

Metabolic phenotyping of mouse mutants in the German Mouse Clinic

The German Mouse Clinic was established as a phenotyping center to provide the scientific community with systematic standardized phenotyping of mouse models from various genetic backgrounds. We found metabolic phenotypes in nine out of 20 mutant lines screened in a primary screen. Based on these findings, the mutants were analyzed in secondary and tertiary screens. Mice of a sample mutant line, isolated from the ENU‐screen at the National Research Center for Environment and Health in Munich, were found to have lower body weight, consume less food, but have higher ratios of metabolized energy per unit body weight compared with their wild‐type littermates. Basal metabolic rate and heat production were simultaneously increased by 16–18%, whereas body fat content was reduced by 11–16%. The combination of various parameters of energy consumption, expenditure and energy storage illustrate the metabolic demands of the sample mutant mouse line and demonstrate the utility of the powerful phenotyping tool used at the German Mouse Clinic.