Hiroshi Ichimura

Prof. Hiroshi Ichimura

Department of Viral Infection and International Health, Graduate School of Advanced Preventive Medical Sciences/Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan

Research Focus & Metrics

Academic Career Length

36Years (1991-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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AIAzumi Ishizaki
Azumi Ishizaki
XBXiuqiong Bi
Xiuqiong Bi
LNLam Van Nguyen
Lam Van Nguyen
KMKazunori Matsuda
Kazunori Matsuda
HPHung Viet Pham
Hung Viet Pham
HIHiroshi Ichimura
Hiroshi Ichimura
Here, we investigated the effects of the probiotic strain Lactobacillus casei Shirota (LcS) on immune profiles and intestinal microbial translocation among children infected with human immunodeficiency virus (HIV). This prospective study included 60 HIV-infected children—including 31 without antiretroviral therapy (ART) (HIV(+)) and 29 who received ART for a median of 3.5 years (ART(+)) and 20 children without HIV infection (HIV(−)). Participants were recruited in Vietnam. All children were given fermented milk containing LcS (6.5 × 109 cfu) daily for 8 weeks. Before and after LcS ingestion, blood samples were collected for virological, immunological, and bacteriological analyses. After LcS ingestion, peripheral CD4+ T-cell and Th2 (CXCR3−CCR6−CD4+) counts significantly increased in both HIV-infected groups; Th17 (CXCR3−CCR6+CD4+) counts increased in all three groups; regulatory T-cell (CD25highCD4+) counts decreased in the ART(+) and HIV(−) groups; activated CD8+ cells (CD38+HLA-DR+CD8+) decreased from 27.5% to 13.2% (p < 0.001) in HIV(+) children; and plasma HIV load decreased slightly but significantly among HIV(+) children. No group showed a significantly altered frequency of bacterial 16S/23S rRNA gene detection in the plasma. No serious adverse events occurred. These findings suggest that short-term LcS ingestion is a safe supportive approach with immunological and virological benefits in HIV-infected children.

22 June 2010 in Journal of Medical Virology
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TTTomoaki Tanimoto
Tomoaki Tanimoto
NCNguyen Hung Cuong
Nguyen Hung Cuong
AIAzumi Ishizaki
Azumi Ishizaki
PCPhan Thi Thu Chung
Phan Thi Thu Chung
HHHoang Thi Thanh Huyen
Hoang Thi Thanh Huyen
HIHiroshi Ichimura
Hiroshi Ichimura
To identify hepatitis C virus (HCV) transmission routes among injection drug users in Northern Vietnam, plasma samples were collected from 486 drug users in Hai Phong. Plasma viral RNA was extracted from 323 (66.5%) samples that were positive for anti-HCV antibodies. Portions of the HCV 5′-untranslated (5′UTR)-Core and NS5B genes were amplified by reverse-transcriptase polymerase chain reaction, sequenced directly, and genotyped in 194 and 195 specimens, respectively. Both regions were genotyped in 137 specimens. In the 5′UTR-Core region, genotype 6a was predominant (32.5%), followed by genotype 1a (23.7%), genotype 1b (20.6%), and genotype 6e (14.4%). In the NS5B region, genotype 1a was predominant (42.6%), followed by genotype 1b (24.1%), genotype 6a (14.4%), genotype 3b (7.2%), and genotype 6e (5.1%). Of the 137 specimens with both regions genotyped, 23 (16.8%) showed discordant genotyping results between the two regions, suggesting possible recombination and/or dual infection. Phylogenetic analysis revealed close associations between Hai Phong strains and strains from Southern China: the Yunnan province for genotype 3b; the Guangxi province for genotype 6e; the USA for genotype 1a; and Southern Vietnam for genotypes 1a and 6e. The human immunodeficiency virus (HIV) infection rate among HCV-infected injection drug users was 52.6–55.4% and did not differ significantly by HCV genotype. Most drug users infected with HIV-1 [98.8% (171/173)] were co-infected with HCV. These results suggest multiple routes of HCV transmission among injection drug users in Northern Vietnam that may also be HIV transmission routes. J. Med. Virol. 82:1355–1363, 2010.

1 May 2009 in Journal of Virological Methods
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NHNorimitsu Hosaka
Norimitsu Hosaka
NNNicaise Ndembi
Nicaise Ndembi
AIAzumi Ishizaki
Azumi Ishizaki
SKSeiji Kageyama
Seiji Kageyama
KNKei Numazaki
Kei Numazaki
HIHiroshi Ichimura
Hiroshi Ichimura
A rapid one-step reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay targeting the pol-integrase gene was developed to detect human immunodeficiency virus type 1 (HIV-1) group M. This HIV-1 RT-LAMP assay is simple and rapid, and amplification can be completed within 35min under isothermal conditions at 60 degrees C. The 100% detection limit of HIV-1 RT-LAMP was determined using a standard strain (WHO HIV-1 [97/656]) in octuplicate and found to be 120 copies/ml. The RT-LAMP assay was evaluated for use for clinical diagnosis using plasma samples collected from 57 HIV-1-infected and 40 uninfected individuals in Cameroon, where highly divergent HIV-1 strains are prevalent. Of the 57 samples from infected individuals, 56 harbored group-M HIV-1 strains, such as subtypes A, B, G, F2, and circulating recombinant forms (CRFs) _01, _02, _09, _11, _13; all were RT-LAMP positive. One sample harboring group-O HIV-1 and the 40 HIV-1-uninfected samples were RT-LAMP negative. These findings indicate that HIV-1 RT-LAMP can detect HIV-1 group-M RNA from plasma samples rapidly and with high sensitivity and specificity. These data also suggest that this RT-LAMP assay can be useful for confirming HIV diagnosis, particularly in resource-limited settings.

1 September 2006 in JAIDS Journal of Acquired Immune Deficiency Syndromes
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YKYusuke Koizumi
Yusuke Koizumi
NNNicaise Ndembi
Nicaise Ndembi
MMMichiko Miyashita
Michiko Miyashita
RLRaphael Bvm Lwembe
Raphael Bvm Lwembe
SKSeiji Kageyama
Seiji Kageyama
HIHiroshi Ichimura
Hiroshi Ichimura
Summary: The prevalence of antiretroviral therapy (ART) resistance-associated mutations among HIV-1 strains in western Cameroon was evaluated by genotypically analyzing strains isolated from drug-naive individuals. Proviral DNA was extracted from 54 blood samples and amplified by polymerase chain reaction of protease, reverse transcriptase, integrase, and envelope genes. At least 4 clones per sample were analyzed. Of 54 HIV-1 strains, 45 (83.3%) had a concordant subtype or circulating recombinant form (CRF) designation: 40 CRF02_AG, 2 subtype A1, 2 G, and 1 F2. The remaining 9 (16.7%) had a discordant subtype: 6 subtype A1/CRF02_AG, 2 D/CRF02, and 1 G/CRF02. Protease inhibitor-associated primary resistance mutations were found in 4 (7.4%) cases: M46L with full clones in 1 case, and M46I, M46L, and V82A as minor populations in 1 case each. Reverse transcriptase inhibitor-associated primary resistance mutations were found in 5 (9.8%) samples: Y188C in 2 cases, and L100I, M184V, and V75I in 1 case each, although all of these mutations were found as minor populations. This is one of the first reports of the emergence of primary ART resistance mutations among drug-naive, non-B subtype HIV-1-infected individuals in Cameroon. Follow-up studies should be conducted to assess whether these drug-resistant mutants found as minor populations might impact future ART.

16 January 2009 in Journal of Medical Virology
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MMMichiko Miyashita
Michiko Miyashita
DADorothy M. Agdamag
Dorothy M. Agdamag
TSToshiyuki Sasagawa
Toshiyuki Sasagawa
KMKaori Matsushita
Kaori Matsushita
LSLourdes Ma. Salud
Lourdes Ma. Salud
HIHiroshi Ichimura
Hiroshi Ichimura

1 December 2004 in AIDS Research and Human Retroviruses
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Journal Article
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KKKayoko Kita
Kayoko Kita
NNNicaise CDC Ndembi
Nicaise CDC Ndembi
MEMichel Ekwalanga
Michel Ekwalanga
EIEiji Ido
Eiji Ido
RKRigobert Kazadi
Rigobert Kazadi
HIHiroshi Ichimura
Hiroshi Ichimura
To investigate the prevalence of subtypes A and C, and the existence of recombinants of both subtypes in the southeast of the Democratic Republic of Congo (DRC), blood samples were collected from 27 HIV-infected individuals in Likasi, located in an area bordering close to Zambia, and analyzed phylogenetically. Out of the 24 strains with a positive PCR profile for pol-IN and env-C2V3, 15 (62.5%) had a discordant subtype or CRF designation: one subtype A/G (pol/env), four A/U (unclassified), three G/A, one G/CRF01, three H/A, one J/C, one CRF02 (G)/A, and one U/A. Nine (37.5%) strains had a concordant subtype or CRF designation: five subtype A, two C, one D, and one CRF02/G. The remaining three samples negative for PCR with env-C2V3 primers used in this study were further analyzed with env-gp41 primers and revealed the presence of two profiles: two J/J (pol-IN/env-gp41) and one C/G. These data highlight the presence of a high proportion (16/27, 59.3%) of recombinant strains and a low prevalence (4.1 and 7.4%) of subtype C based on env-C2V3 and pol-IN analyses, respectively, in Likasi. In addition, this is the first report that CRF02_AG exists in DRC, though the epidemiological significance of the existence of CRF02_AG in DRC remains unknown.