Hiromi Katae

Myelodysplastic syndromes and acute myeloid leukemia in cats infected with feline leukemia virus clone33 containing a unique long terminal repeat.

Feline leukemia virus (FeLV) clone33 was obtained from a domestic cat with acute myeloid leukemia (AML). The long terminal repeat (LTR) of this virus, like the LTRs present in FeLV from other cats with AML, differs from the LTRs of other known FeLV in that it has 3 tandem direct 47‐bp repeats in the upstream region of the enhancer (URE). Here, we injected cats with FeLV clone33 and found 41% developed myelodysplastic syndromes (MDS) characterized by peripheral blood cytopenias and dysplastic changes in the bone marrow. Some of the cats with MDS eventually developed AML. The bone marrow of the majority of cats with FeLV clone33 induced MDS produced fewer erythroid and myeloid colonies upon being cultured with erythropoietin or granulocyte‐macrophage colony‐stimulating factor (GM‐SCF) than bone marrow from normal control cats. Furthermore, the bone marrow of some of the cats expressed high‐levels of the apoptosis‐related genes TNF‐α and survivin. Analysis of the proviral sequences obtained from 13 cats with naturally occurring MDS reveal they also bear the characteristic URE repeats seen in the LTR of FeLV clone33 and other proviruses from cats with AML. Deletions and mutations within the enhancer elements are frequently observed in naturally occurring MDS as well as AML. These results suggest that FeLV variants that bear URE repeats in their LTR strongly associate with the induction of both MDS and AML in cats.

Assessment of the Significance of Virulence Factors of Uropathogenic Escherichia coli in Experimental Urinary Tract Infection in Mice

Four Escherichia coli strains, isolated from cystitis patients, belonging to serotype O2:H− and possessing different combinations of urovirulence factors were examined in an experimental pyelonephritis mouse model to assess the relative importance of virulence factors in causation of urinary tract infections (UTI). The results suggest not only that the each virulence factor has a role in causation of UTI but also that the presence of P fimbriae and production of hemolysin significantly reduced the LD50 and ID50 of the strains in the mouse model. The results also demonstrate that the presence of additional virulence factors acts in an additive or synergetic fashion enhancing the cumulative impact of the strain.

Differentiation of vaccine virus from field isolates of feline panleukopenia virus by polymerase chain reaction and restriction fragment length polymorphism analysis

In an attempt to distinguish feline panleukopenia virus (FPLV) live vaccine strains from FPLV field isolates in Japan, we compared restriction fragment length polymorphisms (RFLP) of polymerase chain reaction (PCR)-amplified fragments of live FPLV vaccine strains with those of FPLV Japanese field isolates. On the basis of nucleotide sequence differences between PLI-IV, a live vaccine strain, and FPV-483, a recent field isolate, two restriction enzymes, Dra I and Afa I, were selected for PCR-RFLP analysis of nucleotide (nt) differences at nt 3695 and 4508, respectively. Three live vaccine strains including the PLI-IV strain could be distinguished from the Japanese field isolates by their PCR-RFLP patterns by Afa I, but one live vaccine strain was indistinguishable from the Japanese isolates when Dra I and Afa I were used. The Japanese field isolates were divided into two groups by the profile of PCR-RFLP patterns generated by Dra I and Afa I, suggesting that PCR-RFLP analysis using several enzymes provides a good genetic estimate of strain differentiation. No isolate that shows a Dra I-negative/Afa I-negative pattern has emerged in Japan, indicating the possibility that the live vaccine viruses with a Dra I-negative/Afa I-negative pattern, such as the PLI-Iv strain, are candidates for use as live FPLV vaccine strain in Japan where they can be genetically distinguished from field strains.

Two genomic variations in the E1 region of canine adenovirus type 2 strains

We amplified the E1 region of canine adenovirus type 2 genomes by the polymerase chain reaction (PCR) and analyzed the PCR products by using eight restriction endonucleases. Restriction patterns of the E1 region cleaved with HaeIII and RsaI revealed two genomic variations among the canine adenovirus type 2 strains. Although the clinical significance of two distinct genotypes among the canine adenovirus type 2 strains is currently unknown, these genomic variations are well conserved among different strains in each genotype and suggest that the Japanese field strains, with reference to the E1 region, are different from the non-Japanese strains examined.