Mating Type Gene (MAT) and Itraconazole Susceptibility of Trichophyton tonsurans Strains Isolated in Japan.

Infection by Trichophyton tonsurans is an emerging fungal epidemic in Japan. Itraconazole (ITZ) and terbinafine have been used for the treatment of this infection for 15 years. However, patients with T. tonsurans infections have been shown to remain uncured or to become reinfected, suggesting that subclinical infection or polyphyletic strains and/or antifungal drug-resistant strains might be occurring in Japan. In this study, PCR analysis was performed to confirm the presence of the mating type locus MAT in genomic DNA from 60 Japanese clinical isolates of T. tonsurans, and to assess the previously postulated clonal origin of clinical isolates of this species. Antifungal susceptibility testing on isolates also was performed to confirm the absence of strains resistant to ITZ. PCR analysis proved that all 60 strains contained the MAT1-1 allele, while none contained the MAT1-2 allele. As determined by E-test, the mean MIC of ITZ in the 60 strains was 0.023 mg/L (range 0.002-0.125 mg/L). All strains of T. tonsurans isolated in Japan were clonal and were not resistant to ITZ. Therefore, dermatophytosis due to T. tonsurans is expected to respond to ITZ, since clinical isolates of T. tonsurans tested to date have been susceptible to this antifungal. This infection is proliferating as a subclinical infection in Japan.

Therapeutic efficacy of ABT-737, a Bcl-2 inhibitor, in a canine melanoma cell line.

The small molecule inhibitor, ABT-737, inhibits Bcl-2 that is overexpressed in many tumor cell lines and, in combination with an anticancer drug, can strongly enhance proapoptotic activity. In the present study, we evaluated the inhibitory activity of ABT-737 on the survival of a canine melanoma cell line (MCM-N1). MCM-N1 cell viability was decreased following 24- and 48-hr culture with ABT-737, depending on ABT-737 concentration, while cell viability was unchanged in controls. ABT-737 synergized with carboplatin to promote cell death. Notably, approximately 50% of MCM-N1 cells survived following culture with 2-4 µg/ml of carboplatin; whereas, less than 20% of MCM-N1 cells survived following culture with ABT-737 (1 mM) plus carboplatin (2-10 µg/ml).

The first reported case of canine subcutaneous Cryptococcus flavescens infection.

This report describes the first documented case of subcutaneous infection due to Cryptococcus flavescens in a dog. The chief symptoms of the patient dog were abscessed lesions on the dorsal muzzle, right eyelid, and lower jaw. Biopsy specimens from the lesions on the dorsal muzzle and lower jaw showed pyogranulomatous inflammation with numerous yeast cells. The patient dog was diagnosed with a subcutaneous fungal infection and orally received 5 mg/kg itraconazole once a day for 2 months, the abscesses disappeared. After 1 month at the end of treatment, the skin lesions did not redevelop. Isolates from the biopsy specimens were identified as C. flavescens by molecular analysis as well as morphologic and biochemical examination, indicating that C. flavescens is a potential canine pathogen.

The antagonist activity of lipid IVa on the stimulation by lipid A of TNF-alpha production from canine blood mononuclear cells.

Lipid A, the active component of lipopolysaccharide (LPS), exists in the outer membrane of Gram-negative bacteria and binds to the Toll-like receptor 4 (TLR4) and MD-2 complex. On the other hand, the synthetic precursor of Escherichia coli lipid A, tetraacylated lipid IVa, is an agonist for TLR4 and MD-2 complex in murine, equine and feline cells but is an antagonist for lipid A in human cells. The aim of the study was to examine the function of canine Toll-like receptor 4 (TLR4) and MD-2 complex on canine blood mononuclear cells (BMC), by analyzing lipid A- or lipid IVa-induction of TNF-α production from these cells in order to understand canine innate immune system. After 5-h culture of canine BMC with lipid A (lipid A culture) or lipid IVa (lipid IVa culture), the TNF-α, as determined by ELISA, had increased in the supernatants of the lipid A cultures in a dose-dependent manner, whereas the TNF-α was undetectable in supernatant of lipid IVa-treated cultures. The TNF-α was statistically significantly different between the lipid A and lipid IVa cultures (100 and 1000 ng/ml). TNF-α production from canine BMC was inhibited, in a lipid IVa-dose-dependent manner, when the BMC were pre-cultured with lipid IVa for 60 min and then cultured with lipid A for 5h, while in control BMC cultures production if TNF-α was unchanged. These results indicate that the TNF-α production stimulated by lipid A was competed out by pre-exposing the BMC to lipid IVa. Thus, lipid A is an agonist for TNF-α production in canine BMC, whereas lipid IVa appears to be an antagonist against this lipid A stimulation of canine BMC.

Chronic ulcerative dermatitis caused by Fusarium sporotrichioides.

The present study describes the isolation of Fusarium sporotrichioides from a canine cutaneous ulceration. A 2-year-old male Beagle dog weighing 8.6 kg, with a history of immune-mediated hemolytic anemia (IMHA), had been treated with prednisone for 9 months. Physical examination revealed cutaneous ulceration on the left foreleg. Histopathological examination of skin samples from the ulcerative area revealed many branching hyphae surrounding neutrophils. Since itraconazole (ITZ) is recommended for miscellaneous fungal infections, the dog was treated with ITZ. However, the ulcerative lesions did not improve and after 3 weeks of treatment the dog died due to renal failure. No autopsy was performed. Since the isolate recovered from the biopsy specimen was identified as Fusarium species by morphological characteristics, the animal was diagnosed as having had an infection caused by this mould. The dog's prior prednisone treatment may have played a role in establishing the fungal infection. Comparative sequence analyses of the ITS regions of the clinical isolate with those in GenBank showed that it was 100% identical to F. sporotrichioides and less than 96% similar to ITS of other Fusarium species. Based on these findings, F. sporotrichioides was established as the etiologic agent of the canine infection, a situation that has not been previously reported in dogs, as well as humans.

Experimental infection of bovine mammary gland with prototheca zopfii genotype 1.

Prototheca zopfii is divided into three genotypes, one of which, P. zopfii genotype 2, appears to be the main causative agent of bovine protothecal mastitis. However, the difference in pathogenicity between genotypes 1 and 2 has not been well investigated. In the present study, we experimentally infected normal bovine mammary gland with P. zopfii genotype 1 to investigate its pathogenicity. The mammary gland infected with P. zopfii genotype 1 showed no clinical signs. However, the histopathologic features of the infected mammary gland consisted of interstitial infiltrates of macrophages, plasma cells, lymphocytes, and fibroblasts with neutrophils in acinar lumens. Algae were present in macrophages and free in the alveolar lumens and the interstitium. Histopathology of the resultant tissue samples revealed that genotype 1 also induced a granulomatous lesion in the cow teat, similar to the mastitis lesion due to genotype 2.

Small interfering RNA (siRNA) against the survivin gene increases apoptosis in a canine melanoma cell line.

The effect of down-regulation of survivin expression by small interfering RNA (siRNA) against the canine survivin gene on apoptosis was investigated by transfecting MCM-N1 (a canine malignant oral melanoma cell line) cells with siRNA using cationic liposomes. The siRNA against the canine survivin gene induced an increase in the rate of apoptotic cells and a decrease in the number of viable cells. We also measured sequence-specific down-regulation of survivin expression by reverse transcription-PCR and western blot analysis. The siRNA directed against survivin reduced both mRNA and protein expression in MCM-N1 cells. These findings suggest the importance of survivin in canine melanoma tumors for inducing apoptosis, and reinforce the possibility of using survivin as a putative therapeutic target in canine malignant melanoma tumor.

Detection of autoantibodies against survivin in sera from cancer dogs.

Survivin overexpression has been reported in relation to tumor malignancy, suggesting that it is an unfavorable prognostic marker, and antibody responses to this protein have been confirmed in human cancer patients. In this study, we investigated antibody responses to survivin in canine cancer cases, and examined the prevalence of such responses by enzyme-linked immunosorbent assay (ELISA) using recombinant canine survivin protein as the antigen. The cut-off value for positivity in the anti-survivin ELISA was 0.35, as determined using the mean absorbance +2 S.D. of samples from healthy dogs. Sera from 16 of 59 (27.1%) cancer and 3 of 25 (12%) non-cancer disease dogs were positive on ELISA. The highest positivity rates (>50%) among the cancer cases were seen in dogs with mammary tumor, squamous cell carcinoma and melanoma.

Small interfering RNA (siRNA) against the Bcl-2 gene increases apoptosis in a canine melanoma cell line.

The effects of down-regulation of Bcl-2 expression, by small interfering RNA (siRNA) against the canine Bcl-2 genes, on apoptosis were investigated by transfecting MCM-N1 (canine malignant oral melanoma cell line) cells with siRNA using cationic liposomes. The siRNA against the canine Bcl-2 genes increased the number of apoptotic cells. In addition, sequence-specific down-regulation of Bcl-2 expression was measured by RT-PCR and western blot analysis. The siRNA directed against these genes reduced both mRNA and protein expression in the MCM-N1 cells. Our study suggests the importance of Bcl-2 in canine melanoma tumors for inducing apoptosis and reinforces using Bcl-2 as a putative therapeutic target in canine malignant melanoma tumor.

Effectiveness of small interfering RNA (siRNA) against the Mcl-1 gene in a canine mammary gland tumor cell line.

The effect of down-regulation of Mcl-1 expression by small interfering RNA (siRNA) against the canine Mcl-1 gene on apoptosis was investigated by transfecting CF33 (canine mammary gland tumor cell line) with siRNA using cationic liposomes. The siRNA against canine Mcl-1 increased the rate of apoptotic cells and decreased the numbers of viable cells. Further, sequence-specific down-regulation of Mcl-1 expression was measured by real time-PCR and Western blot analysis. The siRNA directed against the Mcl-1 gene reduced both the mRNA and protein expression in the CF33. Our study suggests the importance of Mcl-1 in canine mammary tumors for inducing apoptosis and reinforces using Mcl-1 as a putative therapeutic target in canine mammary gland tumor.

Characterization of CD34+ cells from canine umbilical cord blood, bone marrow leukocytes, and peripheral blood by flow cytometric analysis.

Characterization of CD34+ cells in canine bone marrow, umbilical cord blood, and peripheral blood was performed by flow cytometric analysis. The ratio of CD34+CD45hi cells, which are absent in human blood, was high in the CD34+ cell fraction, but 98% of these was suggested B-cells. The remaining CD34+CD45lo cells may comprise canine hematopoietic progenitor cells, and these cells accounted for 0.23 +/- 0.07% of the fraction in cord blood, 0.30 +/- 0.07% in bone marrow, and 0.02 +/- 0.01% in peripheral blood.

Missense mutation with/without nonsense mutation of the p53 gene is associated with large cell morphology in human malignant lymphoma.

Mutations in p53 gene exons 5-9 were studied in 44 non-Hodgkin's lymphomas (NHL) consisting of 35 B-NHL and 9 T-NHL. Missense mutations were found in two diffuse large B-cell lymphomas (DLBL) and one peripheral T-cell lymphoma (unspecified). Double transversion missense and nonsense mutations were detected in one DLBL and one adult T-cell leukemia/lymphoma. Silent mutations were found in two DLBL. Detailed histomorphological study showed that cases harboring p53 missense mutation with/without nonsense mutation tended to have larger nuclei with much more prominent nucleoli. Cytomorphometric analysis was therefore conducted by measuring the gross area of 100 lymphoma cell nuclei in 44 cases and the results were compared between lymphomas harboring p53 missense mutation with/without nonsense mutation and lymphomas harboring p53 silent mutation or lacking mutation. It was found that the lymphomas harboring p53 missense mutation with/without nonsense mutation had a highly significantly larger nuclear gross area than lymphomas with silent p53 mutation or lacking mutation (two-sample t-test, P < 0.00001; Exact Wilcoxon rank-sum test, P < 0.00001). This result suggests that p53 mutation might induce enlargement of neoplastic cell nuclei by some molecular mechanism.

Fulminant Epstein-Barr virus (EBV)-associated T-cell lymphoproliferative disorder with hemophagocytosis following autologous peripheral blood stem cell transplantation for relapsed angioimmunoblastic T-cell lymphoma.

Post-transplant lymphoproliferative disorder (PTLD) is a complication that can develop after either solid-organ or hematopoietic stem cell transplantation (HSCT). T-cell PTLD is a rare disorder, especially following autologous HSCT. Here we report a case of T-cell PTLD which occurred after autologous peripheral blood stem cell transplantation (PBSCT) for relapsed angioimmunoblastic T-cell lymphoma (AILT). Three months after the transplant, the patient developed fever with elevated plasma Epstein-Barr virus (EBV)-PCR values. The patient subsequently developed pneumonitis, hepatomegaly and marked pancytopenia due to hemophagocytosis. The patient died of multi-organ failure, despite antiviral and steroid pulse therapy. Our post-mortem study confirmed the marked proliferation of EBV-infected T-cells that differed from the original AILT clone and macrophages/histiocytes were observed in the marrow, liver, lymph nodes and lungs. Phagocytosis was most evident in the bone marrow. The patient's AILT remained in complete remission. To the best of our knowledge, this is the first case of fulminant EBV-associated T-cell lymphoproliferative disorder (LPD) following autologous HSCT.