Molecular cloning of canine Wilms' tumor 1 for immunohistochemical analysis in canine tissues.

Wilms' tumor 1 (WT1) expression has been investigated in various human cancers as a target molecule for cancer immunotherapy. However, few studies have focused on WT1 expression in dogs. Firstly, cDNA of canine WT1 (cWT1) was molecularly cloned from normal canine kidney. The cross-reactivity of the anti-human WT1 monoclonal antibody (6F-H2) with cWT1 was confirmed via Western blotting using cells overexpressing cWT1. Immunohistochemical staining revealed that cWT1 expression was detected in all canine lymphoma tissues and in some normal canine tissues, including the kidney and lymph node. cWT1 is a potential immunotherapy target against canine cancers.

Bimodal immunoglobulin A gammopathy in a cat with feline myeloma-related disorders.

A 10-year-old female spayed mixed breed cat with a subcutaneous mass on the right hind limb was revealed with bimodal monoclonal gammopathy composed of IgA by immunoelectrophoresis and immunofixation. Approximately 1 month after referral, the cat died due to renal failure. Postmortem immunohistopathologic evaluation of the subcutaneous mass revealed neoplastic cell proliferation of plasma cells and giant myeloma cells. Neoplastic cells were also present in the liver and spleen. These results led to the diagnosis of a rare case of feline myeloma-related disorders with extramedullary plasmacytoma infiltrating in multiple locations. This report emphasizes the necessity to accumulate cases with similar clinicopathologic findings in the future.

Expression of O(6)-methylguanine-DNA methyltransferase causes lomustine resistance in canine lymphoma cells.

The DNA repair protein O (6)-methylguanine-DNA methyltransferase (MGMT) causes resistance to nitrosoureas in various human cancers. In this study, we analyzed the correlation between canine lymphomas and MGMT in vitro. Two of five canine lymphoma cell lines required higher concentrations of lomustine to inhibit cell growth by 50%, but their sensitivity to the drug increased when they were cultured with an MGMT inhibitor. Fluorometric oligonucleotide assay and real-time polymerase chain reaction of these cell lines revealed MGMT activity and high MGMT mRNA expression, respectively. We analyzed the methylation status of the CpG islands of the canine MGMT gene by the bisulfite-sequencing method. Unlike human cells, the canine lymphoma cell lines did not show significant correlation between methylation status and MGMT suppression levels. Our results suggest that in canine lymphoma MGMT activity may influence sensitivity to nitrosoureas; thus, inhibition of MGMT activity would benefit nitrosourea-resistant patients. Additional studies are necessary to elucidate the mechanism of regulation of MGMT expression.

La protéine de réparation O6-méthylguanine-DNA méthyltransferase (MGMT) cause de la résistance aux produits nitroso-urée dans divers cancers humains. Dans la présente étude nous avons analysé in vitro la corrélation entre les lymphomes canins et le MGMT. Deux des cinq lignées cellulaires de lymphome canin ont nécessité des concentrations plus élevées de lomustine pour inhiber de 50 % la croissance cellulaire, mais leur sensibilité au médicament augmenta lorsqu'elles furent mises en culture avec un inhibiteur de MGMT. Une épreuve fluorométrique des oligonucléotides et une épreuve d'amplification en chaîne par la polymérase en temps réel sur ces lignées cellulaires ont révélé, respectivement, une activité MGMT et une expression élevée d'ARNm de MGMT. Nous avons analysé le statut de méthylation des ilots CpG du gène MGMT canin par la méthode de séquençage au bisulfite. Contrairement aux cellules humaines, les lignées cellulaires canines de lymphome n'ont pas montré de corrélation significative entre le statut de méthylation et les niveaux de suppression de MGMT. Nos résultats suggèrent que lors de lymphome canin l'activité de MGMT peut influencer la sensibilité aux produits nitroso-urée; ainsi, l'inhibition de l'activité MGMT bénéficierait les patients résistants au nitroso-urée. Des études additionnelles sont nécessaires pour élucider le mécanisme de régulation de l'expression de MGMT.(Traduit par Docteur Serge Messier).

[Increased body mass index in young adults is associated with metabolic syndrome].

OBJECTIVES: Specific Health Examinations and Guidance (Tokutei kenko shinsa/Tokutei hoken shido) are provided for people over 40 years of age to reduce the incidence of metabolic syndrome (MetS). In the present study, we evaluated the importance of weight control in people below 40 years of age. METHODS: Male subjects (n = 877), aged 30 years, without MetS, were examined. Subjects were classified into 3 groups based on body mass index (BMI): non-obese (BMI < 22), pre-obese (22 ≤ BMI < 25), and obese (BMI ≥ 25). Cox proportional hazards regression analysis was performed for each group to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of MetS in individuals in their 40s on the basis of changes in their BMI, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, high-density lipoprotein, and triglyceride levels between 30 and 35 years of age. In addition, subjects were classified into 3 sub-groups based on changes in BMI: stable-decrease (BMI change < 1), slight increase (1 ≤ BMI increase<2), and increase (2 ≤ BMI increase). HRs for the 3 BMI change sub-groups for MetS were calculated for non-obese and pre-obese subjects. RESULTS: There was a significant association between changes in BMI and the incidence of MetS for non-obese individuals in their 40s (HR: 2.80, 95% CI: 1.61-4.88) and pre-obese subjects (HR: 2.00, 95% CI: 1.44-2.77). There were also significant associations between the stable/decrease and increase (HR: 9.39, 95% CI: 1.52-57.70) sub-groups and MetS in the non-obese group, as well as for the slight increase (HR: 2.30, 95% CI: 1.03-5.11) and increase (HR: 10.13, 95% CI: 4.30-23.80) sub-groups in the pre-obese group. CONCLUSIONS: BMI change in young adults is an important risk factor for MetS among individuals in their 40s. Even subjects with a BMI lower than 25 had differences in the risk of developing MetS based on their BMI change sub-group. In the field of occupational health, it will be necessary to promote stable weight control in young adults to reduce the incidence of MetS.

Oncolytic reovirus in canine mast cell tumor.

The usage of reovirus has reached phase II and III clinical trials in human cancers. However, this is the first study to report the oncolytic effects of reovirus in veterinary oncology, focusing on canine mast cell tumor (MCT), the most common cutaneous tumor in dogs. As human and canine cancers share many similarities, we hypothesized that the oncolytic effects of reovirus can be exploited in canine cancers. The objective of this study was to determine the oncolytic effects of reovirus in canine MCT in vitro, in vivo and ex vivo. We demonstrated that MCT cell lines were highly susceptible to reovirus as indicated by marked cell death, high production of progeny virus and virus replication. Reovirus induced apoptosis in the canine MCT cell lines with no correlation to their Ras activation status. In vivo studies were conducted using unilateral and bilateral subcutaneous MCT xenograft models with a single intratumoral reovirus treatment and apparent reduction of tumor mass was exhibited. Furthermore, cell death was induced by reovirus in primary canine MCT samples in vitro. However, canine and murine bone marrow-derived mast cells (BMCMC) were also susceptible to reovirus. The combination of these results supports the potential value of reovirus as a therapy in canine MCT but warrants further investigation on the determinants of reovirus susceptibility.

Establishment of five canine lymphoma cell lines and tumor formation in a xenotransplantation model.

Five novel, canine lymphoma cell lines (Ema, CLC, CLK, Nody-1 and UL-1) were established from dogs suffering from lymphoma and characterized in vitro and in vivo. All cell lines, except CLC, were characterized with T-cell phenotypes, by flow cytometric analysis and polymerase chain reaction for antigen receptor rearrangement. Cell proliferation rates and transcriptional levels of MYC, PTEN, KIT and FLT3 varied between each cell line. Intraperitoneal xenotransplantation of Ema, CLC, Nody-1 and UL-1 lymphoma cell lines into NOD/SCID mice induced ascites, intraperitoneal tumors and severe infiltration of lymphoma cells into the pancreas and mesentery. Establishment of novel canine lymphoma cell lines with different characteristics is critical for elucidating the pathophysiology of canine lymphoma and improving current therapies.

Ehrlichia canis infection in two dogs that emigrated from endemic areas.

Two dogs, emigrated from Zambia and China to Japan, were diagnosed with Ehrlichia canis infection. Both cases had thrombocytopenia, non-regenerative anemia, and hypergloblinemia with polyclonal gammopathy. Case 1 had ataxia of the hind limbs. Severe meningitis was revealed by magnetic resonance imaging examination. Intracytoplasmic inclusions were observed in mononuclear cells of cerebrospinal fluid. Case 2 had a history of bilateral epistaxis, and severe pancytopenia was noticed in complete blood count. Diagnosis was finally achieved by nested polymerase chain reaction and sequence analysis. Thus, even in non-endemic areas, E. canis infection should be included in the differential diagnosis of clinically ill dogs that emigrated from endemic areas.

Development of high-grade B-cell lymphoma concurrent with T-cell chronic lymphocytic leukemia in a dog.

Second malignancies are frequent complications in human patients with chronic lymphocytic leukemia (CLL). However, the clinical details and outcome of this phenomenon were unclear in their canine counterparts. Here, we report a dog with high-grade lymphoma concurrent with T-cell CLL. A 10-year-old male golden retriever presented with lymphadenopathies. The lymph nodes contained large-sized lymphocytes, raising suspicion of high-grade lymphoma. Meanwhile, small lymphocytic lymphocytosis in the peripheral blood was consistent with CLL. Interestingly, molecular biological analyses revealed that CLL cells were of the T-cell type, whereas lymphoma cells were of the B-cell type. Chemotherapy using the L-VCA short protocol was effective for 155 days, but the dog died on day 194 after diagnosis, despite rescue therapies.

Neutropenia associated with osteomyelitis due to Hepatozoon canis infection in a dog.

A 4-year-old, intact male Shiba dog was referred to Yamaguchi University Animal Medical Center, Yamaguchi, Japan, for the following complaints: anorexia, lethargy, intermittent fever, gingival bleeding and abdominal purpura. The dog presented with persistent neutropenia. Histopathological examination of a bone marrow sample revealed round to oval structures that resembled Hepatozoon micromerozoites and formed a "wheel-spoke" pattern. Furthermore, mature neutrophils were observed around these structures. PCR and sequencing using bone marrow aspirate confirmed Hepatozoon canis (H. canis) infection. These findings suggest that the neutropenia observed in this case was associated with osteomyelitis due to H. canis infection. This is the first report of neutropenia associated with H. canis infection. H. canis infection can be included in the differential diagnosis in canine cases of neutropenia in areas where the disease is endemic.

Prekallikrein deficiency in a dog.

Prekallikrein (PK) deficiency is an uncommon disorder in dogs. In this report, we describe a case of a dog that was referred for neurological defects and had a prolonged activated partial thromboplastin time (aPTT) and normal prothrombin time (PT) with no hemostatic defects. By using human PK-deficient plasma, the dog was diagnosed to have PK deficiency. The nucleotide sequence of normal canine PK cDNA was determined and compared with the genomic sequences of PK in the affected dog. The comparison revealed that the dog had a point mutation in exon 8 that leads to an amino acid substitution in the fourth apple domain of PK. This is the first report showing a point mutation of PK in a dog with PK deficiency.

Nafamostat mesilate is not appropriate as an anticoagulant during continuous renal replacement therapy in dogs.

We performed continuous renal replacement therapy (CRRT) in clinically healthy dogs (n=7) to evaluate the utility of nafamostat mesilate (NM) as an anticoagulant. In 3 of the 7 dogs, CRRT had to be discontinued before the target duration due to coagulation in the extracorporeal circuit, into which NM was administered constantly at the rate of 2.0-6.0 mg/kg per hour. The rate of administration of NM was greater than the recommended dose of NM in humans. Further, all the dogs suffered vomiting during CRRT with NM infusion. We therefore recommend that NM is not used as an anticoagulant during CRRT in dogs.

Evaluation of the hemodynamic impact of continuous renal replacement therapy in healthy dogs.

We performed continuous renal replacement therapy (CRRT) on clinically healthy dogs to evaluate the effects of CRRT on hemodynamics. Heart rate, arterial blood pressure, and central venous pressure of the dogs (n=6) were recorded during the procedure, which was performed under general anesthesia. Throughout the CRRT, heart rate and arterial blood pressure were stable. Central venous pressure increased after CRRT termination but returned to the basal level within 30 min. In this study, hemodynamic alterations, including hypotension, hypertension, and arrhythmias, were not observed during CRRT. These observations suggest that the CRRT protocol used in the present study can be safely applied to clinical cases with acute renal failure.

Aberrations of the FHIT gene and Fhit protein in canine lymphoma cell lines.

The fragile histidine triad (FHIT) gene is a tumor-associated gene, and aberrant FHIT gene and protein expression have been described in many types of human tumors. Furthermore, it has been reported that FHIT gene inactivation is induced by hypermethylation of 5' CpG islands in the gene or by genomic deletion around the open reading frame (ORF). In this study, we explored the aberrations in the canine FHIT gene and Fhit protein expression and assessed the methylation status and genomic deletions by using 5 canine lymphoma cell lines. We found that the decrease in the expression of the Fhit protein in canine lymphoma cell lines was similar to that in human tumors. The expression of the wild-type FHIT transcript was reduced in all 5 cell lines. However, we could not confirm the involvement of aberrant methylation events in the 5' CpG islands of the canine FHIT gene. We were able to identify homozygous or heterozygous deletions in the canine FHIT genes in all 5 cell lines. Moreover, a widespread genomic deletion of the FHIT gene, which included the ORF region, was detected in 1 cell line. In the present study, we detected aberrations in the FHIT gene and Fhit protein expression in all 5 canine lymphoma cell lines, and this phenomenon might be an important factor in promoting canine lymphoma.

Application of polymerase chain reaction to analysis of antigen receptor rearrangements to support endoscopic diagnosis of canine alimentary lymphoma.

We evaluated the usefulness of polymerase chain reaction for antigen receptor gene rearrangement analysis (PARR) of endoscopic biopsy specimens for diagnosis of canine alimentary lymphoma. Two endoscopic biopsy specimens were obtained from each lesion in 78 dogs with gastrointestinal symptoms. One specimen was histopathologically examined by a pathologist, and the other was analyzed by PARR. All samples were categorized into three groups [lymphoma (n=4), adenocarcinoma (n=5) and enteritis groups (n=69)] based on the histopathological diagnosis. In the lymphoma group, one case was IgH major-positive, and three cases were TCRgamma-positive, representing clonal expansion of B- and T-cells, respectively. PARR produced negative results for all cases in the adenocarcinoma group. In the enteritis group, six cases were TCRgamma-positive. Two of the six TCRgamma-positive enteritis cases were cytologically diagnosed as lymphoma by fine needle aspiration during a laparotomy. In the enteritis group, the survival times were compared between the TCRgamma-positive and TCRgamma-negative cases. The overall survival time of the TCRgamma-positive enteritis cases was significantly shorter than that of the TCRgamma-negative enteritis cases according to a log-rank test (p<0.0001). With regard to other factors, such as age, clinical signs and the serum albumin concentration, there were no significant differences between the TCRgamma-positive and TCRgamma-negative enteritis cases. In conclusion, PARR is capable of detecting alimentary lymphoma and latent alimentary lymphoma, which cannot be histopathologically diagnosed using endoscopic biopsy specimens. Furthermore, a TCRgamma-positive result in PARR may imply a poor prognosis.

Molecular cloning of the canine fragile histidine triad (FHIT) gene and Fhit protein expression in canine peripheral blood mononuclear cells.

A fragile histidine triad (FHIT) gene has been studied as a tumor-associated gene in humans. The aberrant FHIT gene and its protein expression have been reported in many types of human cancers. The present study explored the canine FHIT gene structure and its protein expression in the peripheral blood mononuclear cells of healthy dogs by RT-PCR, RACE and immunoblot analysis. The obtained canine FHIT gene contained nine small exons and was located on canine chromosome 20. Furthermore, we identified an alternative splicing form of the FHIT transcript. The deduced amino acid sequence was well conserved between species, and anti-human Fhit antibody could be used to detect the canine Fhit protein. These findings will be useful for future research.

Use of formalin-fixed paraffin-embedded tissue and single-strand conformation polymorphism analysis for polymerase chain reaction of antigen receptor rearrangements in dogs.

PCR for antigen receptor gene rearrangement analysis (PARR) is a new diagnostic method for lymphoid neoplasia. In PARR using formalin-fixed paraffin-embedded tissues (PARR-FFPE), control DNA amplification was successful in only three of five samples. The formalin fixation times of the three samples were shorter than those of the others. Analysis of the formalin fixation time and DNA amplification controls suggested that a formalin fixation time of less than one week is appropriate. Additionally, application of single strand conformation polymorphism (SSCP) for PARR provided clearer results than conventional PARR in 16 unfixed tissues and three FFPE tissues. These results show that PARR-FFPE is viable for tissues with an appropriate formalin fixation time and that application of FFPE and SSCP for PARR are useful for diagnosis and retrospective study of canine lymphoid neoplasia.

Superficial necrolytic dermatitis associated with extrapancreatic glucagonoma in a dog.

An 11-year-old Shih Tzu presented with crusting and erythema, mainly on the abdomen and the root of the tail. Based on histopathological findings, blood examinations and necropsy findings, the condition was diagnosed as superficial necrolytic dermatitis associated with a glucagon-secreting extrapancreatic neuroendocrine tumour. Gross necropsy revealed tumour invasion into the spleen, liver, adrenal glands and mesenteric lymph nodes. Immunohistochemical analysis of the neoplastic cells revealed that the tumour was a glucagonoma, consistent with earlier findings of persistent glucagonaemia and hypoaminoacidaemia.

A dog with myelodysplastic syndrome: chronic myelomonocytic leukemia.

An eleven-year-old female pug was referred to Yamaguchi University Animal Hospital for evaluation of anemia and thrombocytopenia. The cytological examination of the peripheral blood showed some giant monocytic lineage blast cells. A few granulocytes and platelets had dysplastic features. On day 7, in addition to increasing the monocytic lineage cells, the dysplastic features of the blood had also increased compared to the initial examination. We performed bone marrow aspiration upon her death. The bone marrow revealed dysplastic features in all three hematopoietic cell lines, and an increase in the monocytic cell line. Based on the features of the bone marrow and the peripheral blood, this case was confirmed to be myelodysplastic syndrome--Chronic myelomonocytic leukaemia (MDS-CMML).

Detection of Borrelia garinii, Borrelia tanukii and Borrelia sp. closely related to Borrelia valaisiana in Ixodes ticks removed from dogs and cats in Japan.

Ticks removed from 1136 dogs and 134 cats all over Japan were examined for Borrelia infection by PCR and sequencing. The 5S-23S rDNA intergenic spacer of Borrelia was detected from two Ixodes persulcatus ticks from two dogs and two unidentified Ixodes spp. from another two dogs in Hokkaido, and two Ixodes granulatus ticks from two cats in Okinawa. Additional 2 I. granulatus from the same cats also showed positive. Sequence analysis of the PCR products revealed that the one from Hokkaido was similar to B. garinii, the three from Hokkaido to B. tanukii, and the four from Okinawa to a novel Borrelia sp. closely related to B. valaisiana. The data was confirmed by analysis of the flagellin gene sequence. Infected ticks carried by companion animals can be introduced into the human environment.

Cloning of the feline GADD45 cDNA and analysis of its mutation in feline lymphoma cell lines.

Growth arrest and DNA damage-inducible protein 45 (GADD45) plays an important role in suppressing multistep carcinogenesis. In this report, we describe the isolation of the complete wild-type feline GADD45 cDNA from feline tissues. Expression of feline GADD45 mRNA was detected in the liver, spleen, kidney, lung, and testis. The predicted amino acid sequences encoded by the full-length feline GADD45 cDNA display sequence homology with those from other vertebrates, and as in the case of human GADD45, cell growth suppression was observed by ectopic expression of feline GADD45. However, no mutations were detected by sequence analysis of feline GADD45 in several feline lymphoma cell lines, indicating that the GADD45 mutation might be uncommon in feline oncogenesis.