Toshihiro Watari

Regional variations and age-related changes detected with magnetic resonance spectroscopy in the brain of healthy dogs

OBJECTIVE To investigate age-related and regional differences in estimated metabolite concentrations in the brain of healthy dogs by means of magnetic resonance spectroscopy (MRS). ANIMALS 15 healthy Beagles. PROCEDURES Dogs were grouped according to age as young (n = 5; all dogs were 2 months old), adult (5; mean age, 4.5 years), or geriatric (5; all dogs were 12 years old). Imaging was performed by use of a 1.5-T MRI system with T1- and T2-weighted spin-echo and fluid-attenuated inversion recovery sequences. Signal intensity measurements for N-acetyl aspartate, creatine, choline, and lactate-alanine (the spectroscopic peaks associated with alanine and lactate could not be reliably differentiated) were determined with MRS, and areas under the spectroscopic peaks (representing concentration estimates) were calculated. Ratios of these metabolite values were compared among age groups and among brain regions with regression analysis. RESULTS The choline-to-creatine ratio was significantly higher in young dogs, compared with other age groups. The N-acetyl aspartate-to-choline ratio was significantly lower in young dogs and geriatric dogs than in adult dogs. When all age groups were considered, the choline-to-creatine ratio was significantly higher and N-acetyl aspartate-to-choline ratio was significantly lower in the frontal lobe than in all other regions. The N-acetyl aspartate-to-creatine ratio was significantly lower in the cerebellum than in other regions. CONCLUSIONS AND CLINICAL RELEVANCE Metabolite ratios varied significantly among age groups and brain regions in healthy dogs. Future studies should evaluate absolute concentration differences in a larger number of dogs and assess clinical applications in dogs with neurologic diseases.

Plasma thrombin- antithrombin complex concentrations in dogs with malignant tumours

IT has been suggested that coagulation abnormalities such as disseminated intravascular coagulation (DIC) might be caused by the excessive activation of coagulation in dogs with malignant tumours (O’Keefe and Couto 1988). Since excessive activation of coagulation leads to over-generation of thrombin, increased concentrations of thrombin measured in circulating blood would indicate an activation of coagulation. Thrombin-antithrombin complexes (TATs), which are formed rapidly after thrombin production, have been identified as a marker of coagulation activation (Pelzer and others 1988). The plasma TAT concentration has been reported to be useful for evaluating the activation of coagulation in dogs (Ravanat and others 1995), and is available as a marker of the hypercoagulable state in dogs with Cushing’s syndrome (Jacoby and others 2001). However, the plasma TAT concentrations in dogs with malignant tumours have not been reported. This short communication describes the plasma TAT concentrations in dogs with benign or malignant tumours and the incidence of a hypercoagulable state in dogs with malignant tumours. The plasma TAT concentrations of three groups of dogs were examined. Group 1 comprised 16 clinically healthy adult dogs; the dogs were considered clinically normal on the basis of physical examination, routine haematological examination and serum biochemical analysis. Group 2 comprised 11 dogs with benign tumours: five with an adenoma, three with a leiomyoma, two with a haemangioma and one with a lipoma. Group 3 consisted of 62 dogs with malignant tumours, this group was further divided into four subgroups: 27 dogs with epithelial tumours, 17 with mesenchymal tumours except haemangiosarcoma; 10 with haemangiosarcomas and eight with haematopoietic tumours. The dogs in groups 2 and 3 were referred to the Animal Medical Center of Nihon University and their tumours were diagnosed by histopathological examination. None of the dogs received any anticoagulants or blood products before blood sampling. Blood samples were collected into tubes containing 0·13M trisodium citrate (nine parts blood to one part anticoagulant) and centrifuged at 2000 g for 10 minutes, and the citrated plasma was frozen at –30°C until analysis. The plasma TAT concentrations were measured by enzyme immunoassay (TAT Test Kokusai-F; International Reagents Corporation). Mann-Whitney U tests were used to compare plasma TAT concentrations between the groups. For statistical analysis, plasma TAT concentrations undetectable by the assay method used (<0·4 ng/ml) were regarded as 0·4 ng/ml. To detect the incidence of a hypercoagulable state, a reference range of plasma TAT concentration was established as the mean (2sd) concentration obtained from group 1. Dogs with plasma TAT concentrations above the reference range were regarded as displaying a hypercoagulable state. The median (range) plasma TAT concentrations were 0·5 (<0·4 to 0·6) ng/ml in group 1, 0·4 (<0·4 to 6·3) ng/ml in group 2 and 1·3 (0·4 to 49·3) ng/ml in group 3; concentrations were significantly higher in group 3 than in group 1 (P<0·0001). However, there was no significant difference in the plasma TAT concentrations of groups 1 and 2 (P=0·8823) (Fig 1). Within group 3, the TAT concentrations were 0·8 (0·4 to 3·8) ng/ml for the dogs with epithelial tumours, 0·7 (0·4 to 49·3) ng/ml for those with mesenchymal tumours, 17·3 (4·4 to 42·5) ng/ml for those with haemangiosarcomas, and 8·2 (2·1 to 19·0) ng/ml for those with haematopoietic tumours. The plasma TAT concentrations were significantly elevated in all subgroups of group 3 (P<0·001, P<0·01, P<0·0001 and P<0·0001, respectively) compared with group 1 (Fig 2). The mean (2sd) plasma TAT concentration of dogs in group 1 was 0·49 (0·12) ng/ml, and thus dogs with plasma TAT concentrations in excess of 0·61 ng/ml were considered as disVeterinary Record (2005) 156, 839-840

Inhibitory effect of stromal cell derived factor-1 on the replication of divergent strains of feline immunodeficiency virus in a feline T-lymphoid cell line

The effect of a CXC-chemokine, stromal cell derived factor-1 (SDF-1), on the replication of divergent strains of feline immunodeficiency virus (FIV) was examined in order to identify the mechanism of cell entry of FIV. A chemotaxis assay, using a modified Boyden chamber method, confirmed the biological activity of recombinant human (rh) SDF-1 for a feline T-lymphoid cell line (Kumi-1). The viral replication of FIV, as measured by the reverse transcriptase (RT) activity in the culture supernatant, was significantly suppressed by addition of rhSDF-1 in a dose-dependent manner in Kumi-1 cells. Furthermore, PCR analysis of the FIV proviral genome indicated that the inhibitory effect of rhSDF-1 on the replication of FIV in Kumi-1 cells was due to the inhibitory effect in the early event of replication. The inhibitory effect on viral replication by exogenous rhSDF-1 was shown for four divergent FIV isolates of subtypes A, B, and D in Kumi-1 cells.

NOD2 mRNA expression and NFkappaB activation in dogs with lymphocytic plasmacytic colitis.

BACKGROUND Nucleotide Oligomerization Domain Two (NOD2) is suggested to be an intracellular pathogen-associated molecular pattern recognition molecule. NOD2, plays a key role against bacteria by triggering a host defense response through activation of the transcription factor NFkappaB and subsequent proinflammatory cytokine production. NOD2 recently was reported to be overproduced in inflamed colonic mucosa in Crohns disease, and to be accompanied by a significant increase in NFkappaB activity. However, few studies to date have investigated intercellular signaling molecules in dogs with lymphocytic plasmacytic colitis (LPC). HYPOTHESIS NOD2 mRNA expression and NFkappaB activation are increased in mucosal biopsies of LPC dogs as compared with control dogs. ANIMALS Five healthy dogs and 19 dogs with LPC. METHODS Descending colon biopsies were obtained endoscopically. Expression of NOD2 mRNA was evaluated by semiquantitative RT-PCR in the colonic mucosa. NFkappaB binding activity was assessed by electrophoretic mobility shift assay. RESULTS NOD2 mRNA expression was approximately 63% greater in LPC dogs than in healthy controls (P = .019). NFkappaB binding activity was approximately 45% higher in the inflamed colonic mucosa of the LPC dogs, as compared with healthy controls (P = .011). No correlations were observed among NOD2 mRNA expression levels, NFkappaB binding activity, and CIBDAI in LPC dogs. CONCLUSIONS AND CLINICAL IMPORTANCE NOD2 mRNA and NFkappaB activity were significantly higher in the inflamed colon of dogs with LPC, as compared with healthy controls. Our data suggest that NOD2 and NFkappaB play an important role in the pathogenesis of LPC.

Thiazole orange-positive platelets in healthy and thrombocytopenic dogs

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The Clinical Efficacy of Dietary Fat Restriction in Treatment of Dogs with Intestinal Lymphangiectasia

Background Intestinal lymphangiectasia (IL), a type of protein‐losing enteropathy (PLE), is a dilatation of lymphatic vessels within the gastrointestinal tract. Dietary fat restriction previously has been proposed as an effective treatment for dogs with PLE, but limited objective clinical data are available on the efficacy of this treatment. Hypothesis/Objectives To investigate the clinical efficacy of dietary fat restriction in dogs with IL that were unresponsive to prednisolone treatment or showed relapse of clinical signs and hypoalbuminemia when the prednisolone dosage was decreased. Animals Twenty‐four dogs with IL. Methods Retrospective study. Body weight, clinical activity score, and hematologic and biochemical variables were compared before and 1 and 2 months after treatment. Furthermore, the data were compared between the group fed only an ultra low‐fat (ULF) diet and the group fed ULF and a low‐fat (LF) diet. Results Nineteen of 24 (79%) dogs responded satisfactorily to dietary fat restriction, and the prednisolone dosage could be decreased. Clinical activity score was significantly decreased after dietary treatment compared with before treatment. In addition, albumin (ALB), total protein (TP), and blood urea nitrogen (BUN) concentration were significantly increased after dietary fat restriction. At 2 months posttreatment, the ALB concentrations in the ULF group were significantly higher than that of the ULF + LF group. Conclusions and Clinical Importance Dietary fat restriction appears to be an effective treatment in dogs with IL that are unresponsive to prednisolone treatment or that have recurrent clinical signs and hypoalbuminemia when the dosage of prednisolone is decreased.

Case report: First confirmed case of canine peritoneal larval cestodiasis caused by Mesocestoides vogae (syn. M. corti) in Japan.

Canine peritoneal larval cestodiasis (CPLC) is an unusual parasitic disease in dogs that is caused by asexual proliferation of larval Mesocestoides. A 12 year-old spayed Shetland sheepdog with abdominal distension was referred to the Animal Medical Center at Nihon University, Japan. The presence of ascites was confirmed by abdominal ultrasonography and X-ray imaging. In addition, a number of parasites were observed in the ascitic fluid collected by abdominal paracentesis. Each of the whitish colored parasites was less than 1mm in size. The parasites were morphologically identified as Mesocestoides sp. tetrathyridia. The parasites had four suckers and calcareous corpuscles, but no hooks or rostellum. Mitochondrial (mt) 12S rDNA and mt cytochrome c oxidase subunit 1 DNA amplified from the tetrathyridia were used for molecular identification to species level. DNA sequence analysis showed that the tetrathyridia shared more than 99% identity with M. vogae (syn. M. corti) for each gene. The patient was treated with a standard dose (5mg/kg) of praziquantel, which was administered subcutaneously twice at an interval of 14 days. This resulted in successful deworming. This is the first case that CPLC was diagnosed in a dog that had never been taken outside of Japan, indicating that M. vogae is distributed in this country.

Activation of nuclear factor-kappa B and cell adhesion molecule mRNA expression in duodenal mucosa of dogs with lymphocytic-plasmacytic enteritis

Lymphocytic-plasmacytic enteritis (LPE) is the most common form of inflammatory bowel disease (IBD) affecting the canine small intestine; however, the molecular basis of the pathogenesis remains unclear. It has recently been hypothesized that the primary defect is impaired innate immune function, as is the case for human IBD. Nuclear factor-kappa B (NFkappaB) plays a central role in innate immunity, and is a major transcriptional regulator of several proinflammatory cytokines, pattern recognition receptors (PRRs) such as toll-like receptors (TLRs), nucleotide-binding oligomerization domain-like receptors and cell adhesion molecules (CAMs). The purpose of this study was to evaluate, in the duodenal mucosa of 21 dogs with LPE and 8 control dogs, the degree of NFkappaB activity and the mRNA expression of two selected cytokines, nucleotide oligomerization domain two (NOD2) receptor and three selected CAMs, all of which are regulated by NFkappaB, using the electrophoretic mobility shift assay and real-time reverse transcription PCR. NFkappaB binding activity was significantly higher in the inflamed duodenal mucosa of the LPE dogs as compared to healthy controls. Furthermore, expression of mRNA for intercellular cell adhesion molecule 1 (ICAM-1) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) was significantly higher and vascular cell adhesion molecule 1 (VCAM-1) mRNA significantly lower in LPE dogs than in healthy controls. However, there was no significant difference in the mRNA levels for TNFα, IL1β and NOD2 between the two groups. These results suggest that NFkappaB and CAMs may play important roles in the pathogenesis of canine LPE.

Dystrophin-deficient muscular dystrophy in an Alaskan malamute

DYSTROPHIN-deficient muscular dystrophy is an X-linked inherited degenerative myopathy. It is the most common form of muscular dystrophy seen in dogs, and is similar to that termed Duchennes muscular dystrophy in human medicine (Shelton and Engvall 2002, Schatzberg and Shelton 2004). Dystrophin-deficient muscular dystrophy has been reported in several breeds, summarised in Table 1 (Shelton and Engvall 2002, Schatzberg and Shelton 2004, Wieczorek and others 2006, Baltzer and others 2007, Klarenbeek and others 2007, Walmsley and others 2010). This short communication reports a confirmed case of dystrophin-deficient muscular dystrophy in an Alaskan malamute, which has only previously been suspected in this breed (Cardinet and Holliday 1979). View this table: Table 1 Breeds of dog confirmed to be affected by dystrophin-deficient muscular dystrophy A four-month-old, 12.9 kg, intact male Alaskan malamute was presented to the Animal Medical Center at Nihon University with a one-month history of anorexia, excessive salivation, exercise intolerance, dysphagia and impaired growth. In addition to these clinical signs, the owner had also observed abnormal movement of the tongue and difficulty when drinking water. The owner reported no deficits in mentation or in behaviour, learning or house training compared with its littermates. Rectal temperature was slightly elevated (39.9°C). Physical examination revealed hypertrophy of the tongue and laryngopharyngeal muscles, but other muscles appeared relatively unaffected and without pain on palpation. Postural reactions and spinal reflexes were normal, but the swallowing reflex was poor and abnormal movement of the tongue was also apparent. In addition, there was a reduced menace reaction with normal palpebral reflex and nasal sensation. Complete blood count was unremarkable but serum biochemistry indicated elevated creatine kinase (CK) activity …

Successful Resolution of Esophageal Granulomas in a Dog Infected with Spirocerca lupi

ABSTRACT A 13-year-old female Labrador Retriever presented with chronic regurgitation. Radiography and computed tomography (CT) revealed nodules in the caudal esophagus. Upper gastrointestinal endoscopy followed by histopathological examination revealed esophageal granulomas caused by Spirocerca lupi. The infection was treated with milbemycin oxime. The therapy was successful, and a remarkable reduction in granulomas was observed. This case report describes the diagnostic imaging findings and treatment outcome of a dog with S. lupi infection in Japan.