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Biomedical subjects

I Takashima

Publications and source records attributed to I Takashima.

At least 55 records · Page 3Linked to original sources
PubMed1998

Urine-associated horizontal transmission of Seoul virus among rats.

To understand the mode of transmission of Seoul type hantavirus in Wistar rats, we examined the shedding of the virus and antibody production in infected rats. When 1-day-old rats were inoculated with the KI-83-262 strain of Seoul virus, S segment of the viral genome was detected in lungs, clots, urine, saliva, submaxillary glands, rectums, and kidneys by nested reverse transcriptase PCR. On the other hand, when 8-week-old rats were infected with the virus, viral genome was detected only in the lungs and rectum. In newborn rats intranasally administered urine from infected newborn rats, four of six rats shed the virus into their urine. In addition, three of eight rats kept in the same cage with infected animals also shed the virus into urine. Moreover, the virus genome was detected in the urine of urban rats (Rattus norvegicus) in an enzootic focus. These findings suggest that the urine containing virus from infected rats is an actual source of the Seoul virus infection.

Administration, Intranasal↗
PubMed1998

Urine-associated horizontal transmission of Seoul virus among rats.

To understand the mode of transmission of Seoul type hantavirus in Wistar rats, we examined the shedding of the virus and antibody production in infected rats. When 1-day-old rats were inoculated with KI-83-262 strain of Seoul virus, the S segment of the viral genome was detected in lungs, clots, urine, saliva, submaxillary glands, rectums, and kidneys by nested reverse transcriptase PCR. On the other hand, when 8-week-old rats were infected with the virus, viral genome was detected only in the lungs and rectum. In uninfected newborn rats intranasally administered urine from infected newborn rats, four of six rats shed the virus into their urine. In addition, three of eight rats kept in same cage with infected animals also shed the virus into urine. Moreover, the virus genome was detected in the urine of urban rats (Rattus norvegicus) in an enzootic focus. These findings suggest that the urine containing virus from infected rats is an actual source of Seoul virus infection.

Administration, Intranasal↗
PubMed1998

Epidemiology of tick-borne encephalitis in Japan.

A tick-borne encephalitis (TBE) patient has not been reported for many years in Japan although a serological survey of domestic animal sera suggested the presence of TBE foci in Hokkaido, the northern island of Japan. In October 1993 in Hokkaido, a severe encephalitis case in a farm wife was diagnosed as tick-borne encephalitis. Serological examination of paired sera showed a rise of neutralization (NT) antibody titer to Russian spring summer encephalitis virus. A sero-epizootiological survey of dogs showed that the TBE-related virus was prevalent in the area. Three virus isolates were obtained from the blood of sentinel dogs and the antigenic analysis grouped the isolates into TBE-related viruses. Sequence analysis of envelope protein gene identified one of the isolates as the same subtype as Russian spring summer encephalitis (Far-Eastern TBE) virus. The results provide the evidence that TBE is endemic in a certain area of Japan.

Agricultural Workers' Diseases↗
PubMed1998

Putative origin of Yersinia pseudotuberculosis in western and eastern countries. A comparison of restriction endonuclease analysis of virulence plasmids.

Yersinia pseudotuberculosis isolates from Russia east of Moscow, Korea and mainland China were used for restriction endonuclease analysis of virulence plasmid (REAP) and findings were compared with REAP of isolates from Japan and Western countries. An identical REAP pattern of each serogroup 1a, 1b, 3, 4a and 4b strain was observed among isolates from Russia, Korea, mainland China, and Japan but such was absent in West European strains. Therefore, the possibility that the origin of Y. pseudotuberculosis between West Europe and eastern Eurasia east of Moscow may be from a different clone should be considered.

Animals↗
PubMed1998

Isolation of tick-borne encephalitis virus from Ixodes ovatus (Acari: Ixodidae) in Japan.

A case of tick-borne encephalitis (TBE) was found in a farming area located in the southern part of Hokkaido, Japan, in 1993. TBE viruses were isolated from sentinel dogs in the area where the human case occurred in 1995. Ticks were collected in the area by 2 collection methods in 1995 and virus isolation was conducted on ticks in 1995 and 1996. Ixodes ovatus Neumann was found to be the predominant tick species in the area. In 1996, 2 virus strains were isolated from 600 I. ovatus ticks (300 females and 300 males), giving the minimum infection rate of 0.33% (2 of 600). The 2 virus strains were identified as TBE virus by antigenic analysis using monoclonal antibodies and the indirect immunofluorescent antibody test. The results showed that I. ovatus was a suspected vector of the emerging TBE virus in Hokkaido.

Animals↗
PubMed1998

Antigenic characterization of Hantaan and Seoul virus nucleocapsid proteins expressed by recombinant baculovirus: application of a truncated protein, lacking an antigenic region common to the two viruses, as a serotyping antigen.

Hantaan virus (HTN) and Seoul virus (SEO) are members of the genus Hantavirus in the family Bunyaviridae and are causative agents of hemorrhagic fever with renal syndrome. The complete and truncated nucleocapsid proteins (NP) of HTN and SEO were expressed by a recombinant baculovirus system. Antigenic characterization of the NP using monoclonal antibodies (MAbs) indicated that the binding sites for the serotype-specific MAbs were located between amino acids (aa) 155 and 429. A Western blot assay indicated that the serotype-specific epitopes were conformation dependent. An indirect immunofluorescence antibody (IFA) assay with the truncated NP (aa 155 to 429) was able to distinguish convalescent-phase sera from HTN and SEO patients. However, the antibody titers with the truncated NP were lower than those with the whole NP. The truncated NP of SEO (aa 155 to 429) could be used as an enzyme-linked immunosorbent assay (ELISA) antigen, but the truncated NP from HTN lost its reactivity when used for ELISA. The IFA assay using baculovirus-expressed truncated NP as an antigen is a rapid, simple, and safe test for distinguishing between HTN and SEO infections by serotype.

Adult↗
PubMed1998

Evaluation of serological diagnosis of Borna disease virus infection using recombinant proteins in experimentally infected rats.

We produced two recombinant Borna disease virus (BDV) proteins, p40 and p24, by using a baculovirus vector as a diagnostic antigen. Antigenicities of these recombinant proteins were evaluated by immune rabbit sera. Recombinant p40 was a more sensitive antigen than p24 for the detection of antibodies in infected rats. Rats inoculated with BDV within 24 hr after birth showed higher detection rates of viral RNA and viral proteins from the brain than rats inoculated at 4 weeks-old. Depending on the age of infection and the time postinfection, the detection of BDV RNA, protein, or anti-BDV antibody did not always correlate in individuals. We suggest both serological and molecular biological methods are needed in the diagnosis of BDV infection.

Animals↗
PubMed1998

Coxiellosis in domestic and wild birds from Japan.

Serological evidence of infection with Coxiella burnetii was found in 41 (2%) of 1,951 domestic birds and in 167 (19%) of 863 wild birds from 17 and 5 prefectures in Japan, respectively, by microagglutination (MA) test. The bacteriological evidence of the infection was found in 17 (41%) of 41 domestic birds and 37 (22%) of 167 wild birds by the nested polymerase chain reaction (PCR). In addition, C. burnetii was isolated from five each of serum, spleen and fecal specimens from five jungle crows (Corvus macrorhynchos) (whose sera were positive by both the MA test and PCR) by inoculating laboratory mice. Domestic quail (Coturnix coturnix japonica) (3%), domestic muscovy ducks (Cairina moschata) (3%), domestic chickens (2%), domestic mallards (Anas platyrhynchos domesticus) (2%), carrion crows (Corvus corone) (37%), jungle crows (35%), and wild rock doves (Columba livia) (6%) showed serologic evidence of experience with C. burnetii. There was a tendency for a high prevalence among birds living and/or feeding in close proximity to infected livestock. This suggests that these birds are one of the less important links in maintaining the whole cycle of C. burnetii infection.

Agglutination Tests↗
PubMed1998

A single-tube RT-PCR method for the detection of Borna disease viral genomic RNA.

For detecting Borna disease virus (BDV) genomic stranded RNA, single-tube reverse transcription-polymerase chain reaction (St RT-PCR) was developed to equal the sensitivity of RT-nested PCR but with reduced risk of contamination. BDV-genomic stranded RNA was synthesized in vitro using plasmid cDNA of BDV p24 region as a template and RNA was also extracted from BDV-persistently infected MDCK (MDCK/BDV) cells. Both RNAs were amplified by St RT-PCR in which a single round of RT and a single round of PCR were performed in the same tube. Ten copies of synthesized RNA could be amplified by St RT-PCR, indicating that St RT-PCR method is as sensitive as the ordinary RT-nested PCR method. Furthermore, this method was applied to quantify the exact copy number of genomic RNA in MDCK/BDV cells. Signals were obtained from the samples containing more than 1 pg total cellular RNA. From the results, approximately 100 copies of BDV genomic RNA exist in one MDCK/BDV cell. BDV genomic RNA from the in vivo RNA samples using St RT-PCR, indicating this method is applicable for the epidemiological study of BDV without contamination.

Animals↗
PubMed1997

Phylogenetic analyses of Chlamydia psittaci strains from birds based on 16S rRNA gene sequence.

The nucleotide sequences of 16S ribosomal DNA (rDNA) were determined for 39 strains of Chlamydia psittaci (34 from birds and 5 from mammals) and for 4 Chlamydia pecorum strains. The sequences were compared phylogenetically with the gene sequences of nine Chlamydia strains (covering four species of the genus) retrieved from nucleotide databases. In the neighbor-joining tree, C. psittaci strains were more closely related to each other than to the other Chlamydia species, although a feline pneumonitis strain was distinct (983 to 98.6% similarity to other strains) and appeared to form the deepest subline within the species of C. psittaci (bootstrap value, 99%). The other strains of C. psittaci exhibiting similarity values of more than 99% were branched into several subgroups. Two pigeon strains and one turkey strain formed a distinct clade recovered in 97% of the bootstrapped trees. The other pigeon strains seemed to be distinct from the strains from psittacine birds, with 88% of bootstrap value. In the cluster of psittacine strains, three parakeet strains and an ovine abortion strain exhibited a specific association (level of sequence similarity, 99.9% or more; bootstrap value, 95%). These suggest that at least four groups of strains exist within the species C. psittaci. The 16S rDNA sequence is a valuable phylogenetic marker for the taxonomy of chlamydiae, and its analysis is a reliable tool for identification of the organisms.

Abortion, Veterinary↗
PubMed1997

A case of tick-borne encephalitis in Japan and isolation of the the virus.

A case of tick-borne encephalitis (TBE) has not been reported for many years in Japan, although a serological survey of sera from domestic animals suggested the presence of TBE foci in Hokkaido, the northern island of Japan. Studies were conducted to prove the presence of an endemic focus of TBE virus in Japan by means of serology and virus isolation. In October 1993 in Hokkaido, a severe case of encephalitis in a dairy farmer's wife was diagnosed as TBE. Serological examination of paired serum specimens showed a rise in the neutralization antibody titer to Russian spring summer encephalitis virus. A seroepizootiological survey of dogs showed that the TBE-related virus was prevalent in the area. Three virus isolates were obtained from the blood of sentinel dogs, and antigenic analysis grouped the isolates into TBE-related viruses. Sequence analysis of the envelope protein gene identified one of the isolates as being of the same subtype as the Russian spring summer encephalitis (Far Eastern TBE) virus. The results provide evidence that TBE is endemic in a certain area of Japan.

Animals↗
PubMed1997

[A case of advanced hepatocellular carcinoma with portal invasion effectively treated by continuous intra-arterial chemotherapy with 5-fluorouracil].

A 79-year-old male diagnosed as advanced hepatocellular carcinoma with portal invasion was treated by continuous intra-arterial chemotherapy of 5-FU, which was continuously administered for 72 hours at a dose of 333 mg/mm/day every 2 weeks and repeated 12 times. Total dose of 5-FU was 14.4 g. Toxicity of this therapy was not recognized. Levels of AFP were reduced from 4385.6 ng/ml to 11.9 for 6 months. No tumor was recognized on CT scan at 6 months after starting this therapy, after 15 months of this therapy, the patient is alive and disease-free. Given the above results, continuous intra-arterial administration of this 5-FU therapy may be effective for patients with hepatocellular carcinoma.

Aged↗
PubMed1996

Modes of Seoul virus infections: persistency in newborn rats and transiency in adult rats.

To understand the mode of persistent infection of Seoul virus in rodents, we examined the distribution of the virus genome and antibody production in infected rats. When 1-day-old rats were inoculated with the KI-83-262 strain, the S segment of viral genome was detected in sera, clots, lungs and kidneys from 3 to 184 days post inoculation (d.p.i.) by nested reverse transcriptase PCR. On the other hand, when 7-week-old rats were infected with this virus, viral genome was detected only in the lungs from 3 to 50 d.p.i. The neutralizing antibody titers of rats inoculated at 1-day of age were higher than those of rats inoculated at 7 weeks of age. In both age groups, however, the IgG avidity of antibody increased along with the course of infection. We found that urban rats (Rattus norvegicus) infected early in life harbored the virus for more than 6 months.

Animals↗
PubMed1996

Polymerase chain reaction for the detection of Chlamydia psittaci in the feces of budgerigars.

The polymerase chain reaction (PCR) targeting the ompA gene of Chlamydia psittaci was evaluated for its ability to detect chlamydiae in fecal specimens of budgerigars as compared with isolation procedures using cell culture and embryonated egg inoculations. Several procedures for PCR template DNA preparation were compared so as to determine their detection levels for chlamydiae propagated in cell culture in the presence of fecal materials. Tween-20 and proteinase K treatments followed by centrifugation of the template DNA were found to be an appropriate procedure for DNA preparation for primary PCR. Subsequent nested PCR was shown to detect 4.8 IFU/ml or 84 particles/ml of chlamydiae. Chlamydiae in 50 fecal specimens from apparently healthy budgerigars were examined by nested PCR and several other methods. Nested PCR detected chlamydiae at a higher rate (12/50, 24%) than the isolation procedure in embryonated eggs (6/50, 12%). Primary PCR combined with the isolation procedure in cell culture gave a detection rate (5/50, 10%) similar to that of isolation from embryonated eggs. Detection rates by primary PCR (1/50, 2%) and in cell culture (0%) were inferior to the other procedures.

Animals↗
PubMed1996

Experimental Chlamydia psittaci infection of Japanese quail.

Japanese quail were used for the infection model of avian chlamydiosis. One-day-old Japanese quail were highly susceptible to lethal infection by a Chlamydia psittaci strain of budgerigar origin upon inoculation via the air sac route with 10(4.1) FFU of the organism, showing an acute and lethal course with chlamydial propagation. In contrast, 7-day-old quail developed resistance to the infection as shown by the lack of lethal effect with the same dose. The resistance of 7-day-old birds was abolished by immunosuppressive treatment with cyclophosphamide. Upon inoculation with a sublethal dose of 10(2.1) FFU, latent infection was established in 1-day-old birds with a minimum number of the organism. The latent infection in the birds was converted to the lethal form by treatment with cyclophosphamide along with chlamydial propagation and suppression of antibody production.

Aging↗
PubMed1996

Serotyping of Chlamydia trachomatis from inclusion conjunctivitis by polymerase chain reaction and restriction fragment length polymorphism analysis.

A molecular biological method of detecting and serotyping Chlamydia trachomatis (C. trachomatis) directly from conjunctival specimens by polymerase chain reaction (PCR) was developed and applied to the diagnosis of inclusion conjunctivitis. We amplified 1.2 kbp DNA fragments of ompA gene from 15 reference strains of C. trachomatis by two-step PCR using two pairs of primers. Restriction fragment length polymorphism analysis using a combination of three endonucleases (HinfI, HindIII and HhaI) completely differentiated 13 of the 15 serovars; the exceptions were B and Ba. We then used this method for 18 strains of C. trachomatis isolated from Japanese patients with inclusion conjunctivitis, serotyping them into six groups: D (5/18), G (5/18), E (3/18), H (2/18), F (1/18), and K (1/18). In our comparison of cell culture isolation with PCR analysis of 38 conjunctival swabs from 35 patients in Sapporo with follicular conjunctivitis, 8 were positive in culture isolation and were also positive in two-step PCR. Twenty-five of 26 strains (the 18 isolated strains and 8 strains amplified by two-step PCR) were genotyped to D, G, H, E, F, and K. One isolated strain could not be identified. The C. trachomatis which causes inclusion conjunctivitis in Japan appears to have a distribution of serovars similar to that of the sexually transmitted diseases.

Adolescent↗