Hiroaki Iwata

Publications (13)35.74 Total impact

• Source

  Available from: Osamu Gotoh

  Dataset: Benchmarking spliced alignment programs

  Hiroaki Iwata, Osamu Gotoh
• Source

  Available from: Osamu Gotoh

  Dataset: Information contens of intron recognition signal

  Hiroaki Iwata, Osamu Gotoh
• Article: Bullous pemphigoid: role of complement and mechanisms for blister formation within the lamina lucida.

  Hiroaki Iwata, Yasuo Kitajima
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  ABSTRACT: Bullous pemphigoid (BP), an autoimmune subepidermal blistering skin disease, demonstrates tense blisters with or without widespread erythema, blistering along the lamina lucida, immunoglobulin G and/or complement deposits at the basement membrane zone, and the presence of circulating autoantibodies against hemidesmosomal molecules. These autoantibodies usually react against 180-kDa and/or 230-kDa proteins, designated as BP180 and BP230, respectively. The precise blistering mechanisms after autoantibodies bind to antigens are not fully understood. Immune complexes are thought to initially activate the complement cascade, which may induce activation of proteases and/or cytokines and cause dermal-epidermal separation. However, why does separation run specifically within the lamina lucida in a space as narrow as 500 nm wide? This review mainly focuses on the possible mechanisms of BP-specific blistering and how separation occurs along the lamina lucida, based on existing evidence.
  Experimental Dermatology 04/2013; · 3.54 Impact Factor
• Article: Benchmarking spliced alignment programs including Spaln2, an extended version of Spaln that incorporates additional species-specific features.

  Hiroaki Iwata, Osamu Gotoh
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  ABSTRACT: Spliced alignment plays a central role in the precise identification of eukaryotic gene structures. Even though many spliced alignment programs have been developed, recent rapid progress in DNA sequencing technologies demands further improvements in software tools. Benchmarking algorithms under various conditions is an indispensable task for the development of better software; however, there is a dire lack of appropriate datasets usable for benchmarking spliced alignment programs. In this study, we have constructed two types of datasets: simulated sequence datasets and actual cross-species datasets. The datasets are designed to correspond to various real situations, i.e. divergent eukaryotic species, different types of reference sequences, and the wide divergence between query and target sequences. In addition, we have developed an extended version of our program Spaln, which incorporates two additional features to the scoring scheme of the original version, and examined this extended version, Spaln2, together with the original Spaln and other representative aligners based on our benchmark datasets. Although the effects of the modifications are not individually striking, Spaln2 is consistently most accurate and reasonably fast in most practical cases, especially for plants and fungi and for increasingly divergent pairs of target and query sequences.
  Nucleic Acids Research 07/2012; · 8.03 Impact Factor
• Article: Overexpression of monocyte chemoattractant protein-1 in the overlying epidermis of multicentric reticulohistiocytosis lesions: a case report.

  Hiroaki Iwata, Yuka Okumura, Mariko Seishima, Yumi Aoyama
  International journal of dermatology 04/2012; 51(4):492-4. · 1.18 Impact Factor
• Article: Characterization of NLRP3 variants in Japanese cryopyrin-associated periodic syndrome patients.

  Hidenori Ohnishi, Takahide Teramoto, Hiroaki Iwata, Zenichiro Kato, Takeshi Kimura, Kazuo Kubota, Ryuta Nishikomori, Hideo Kaneko, Mariko Seishima, Naomi Kondo
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  ABSTRACT: The etiology of cryopyrin-associated periodic syndrome (CAPS) is caused by germline gene mutations in NOD-like receptor family, pryin domain containing 3 (NLRP3)/cold-induced autoinflammatory syndrome 1 (CIAS1). CAPS includes diseases with various severities. The aim of this study was to characterize patients according to the disease severity of CAPS. Five Japanese patients with four kinds of gene variations in NLRP3 were found and diagnosed as CAPS or juvenile idiopathic arthritis. Two mutations in NLRP3, Y563N and E688K, found in CAPS patients exhibit significant positive activities in the nuclear factor-κB reporter gene assay. Increased serum interleukin (IL)-18 levels were only observed in severe cases of CAPS. In mild cases of CAPS, the serum IL-18 levels were not increased, although lipopolysaccharide- or hypothermia-enhanced IL-1β and IL-18 production levels by their peripheral blood mononuclear cells were detectable. This series of case reports suggests that a combination of in vitro assays could be a useful tool for the diagnosis and characterization of the disease severity of CAPS.
  Journal of Clinical Immunology 12/2011; 32(2):221-9. · 3.08 Impact Factor
• Article: Three siblings with systemic lupus erythematosus.

  En Shu, Yoshiro Ichiki, Chie Moriya, Hiroaki Iwata, Yasuo Kitajima, Mariko Seishima
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  ABSTRACT: We present the cases of three siblings with systemic lupus erythematosus (SLE). The diagnosis was made when the sisters were of age 21, 25 and 28 years. They shared some clinical features, including typical facial rash, photosensitivity and Raynaud's phenomenon, and tested positive for antinuclear antibodies. However, their symptoms and clinical courses varied. Human leukocyte antigen (HLA) typing revealed that DR4 and A2 were present in all three sisters, while HLA type A11, B35 and B54 were each found in two of the three sisters. The two elder sisters developed lupus glomerulonephritis 8 and 11 years after the onset of SLE. It is suggested that there are genes responsible for the onset of the disease and also unknown regulatory genes other than HLA result in different phenotypes.
  The Journal of Dermatology 12/2011; 39(2):164-7. · 1.49 Impact Factor
• Article: Applicability of radiocolloids, blue dyes and fluorescent indocyanine green to sentinel node biopsy in melanoma.

  Hisashi Uhara, Naoya Yamazaki, Minoru Takata, Yuji Inoue, Akihiro Sakakibara, Yasuhiro Nakamura, Keisuke Suehiro, Akifumi Yamamoto, Riei Kamo, Kosuke Mochida, [......], Hiroaki Iwata, Takafumi Kadono, Yoshitaka Kai, Shoichi Watanabe, Satoru Murata, Tetsuya Ikeda, Hidekazu Fukamizu, Toshihiro Tanaka, Naohito Hatta, Toshiaki Saida
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  ABSTRACT: Patients with primary cutaneous melanoma underwent sentinel node (SN) mapping and biopsy at 25 facilities in Japan by the combination of radiocolloid with gamma probe and dye. Technetium-99m ((99m)Tc)-tin colloid, (99m)Tc-phytate, 2% patent blue violet (PBV) and 0.4% indigo carmine were used as tracers. In some hospitals, 0.5% fluorescent indocyanine green, which allows visualization of the SN with an infrared camera, was concomitantly used and examined. A total of 673 patients were enrolled, and 562 cases were eligible. The detection rates of SN were 95.5% (147/154) with the combination of tin colloid and PBV, 98.9% (368/372) with the combination of phytate and PBV, and 97.2% (35/36) with the combination of tin colloid or phytate and indigo carmine. SN was not detected in 12 cases by the combination method, and the primary tumor was in the head and neck in six of those 12 cases. In eight of 526 cases (1.5%), SN was detected by PBV but not by radiocolloid. There were 13 cases (2.5%) in which SN was detected by radiocolloid but not by PBV. In 18 of 36 cases (50%), SN was detected by radiocolloid but not by indigo carmine. Concomitantly used fluorescent indocyanine green detected SN in all of 67 cases. Interference with transcutaneous oximetry by PVB was observed in some cases, although it caused no clinical trouble. Allergic reactions were not reported with any of the tracers. (99m)Tc-tin colloid, (99m)Tc-phytate, PBV and indocyanine green are useful tracers for SN mapping.
  The Journal of Dermatology 09/2011; 39(4):336-8. · 1.49 Impact Factor
• Article: False-negative sentinel lymph node biopsy resulting from obstruction of lymphatic basin by nodal metastasis: a case report of malignant melanoma.

  Hiroaki Iwata, Hideki Kamiya, Yasuo Kitajima
  The Journal of Dermatology 05/2011; 38(11):1121-4. · 1.49 Impact Factor
• Source

  Available from: Osamu Gotoh

  Article: Comparative analysis of information contents relevant to recognition of introns in many species.

  Hiroaki Iwata, Osamu Gotoh
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  ABSTRACT: The basic process of RNA splicing is conserved among eukaryotic species. Three signals (5' and 3' splice sites and branch site) are commonly used to directly conduct splicing, while other features are also related to the recognition of an intron. Although there is experimental evidence pointing to the significant species specificities in the features of intron recognition, a quantitative evaluation of the divergence of these features among a wide variety of eukaryotes has yet to be conducted. To better understand the splicing process from the viewpoints of evolution and information theory, we collected introns from 61 diverse species of eukaryotes and analyzed the properties of the nucleotide sequences relevant to splicing. We found that trees individually constructed from the five features (the three signals, intron length, and nucleotide composition within an intron) roughly reflect the phylogenetic relationships among the species but sometimes extensively deviate from the species classification. The degree of topological deviation of each feature tree from the reference trees indicates the lowest discordance for the 5' splicing signal, followed by that for the 3' splicing signal, and a considerably greater discordance for the other three features. We also estimated the relative contributions of the five features to short intron recognition in each species. Again, moderate correlation was observed between the similarities in pattern of short intron recognition and the genealogical relationships among the species. When mammalian introns were categorized into three subtypes according to their terminal dinucleotide sequences, each subtype segregated into a nearly monophyletic group, regardless of the host species, with respect to the 5' and 3' splicing signals. It was also found that GC-AG introns are extraordinarily abundant in some species with high genomic G + C contents, and that the U12-type spliceosome might make a greater contribution than currently estimated in most species. Overall, the present study indicates that both splicing signals themselves and their relative contributions to short intron recognition are rather susceptible to evolutionary changes, while some poorly characterized properties seem to be preserved within the mammalian intron subtypes. Our findings may afford additional clues to understanding of evolution of splicing mechanisms.
  BMC Genomics 01/2011; 12:45. · 4.07 Impact Factor
• Article: Generalized eruption with histopathologic toxic epidermal necrolysis caused by occupational exposure to thiourea dioxide.

  Yumi AOYAMA, Keiko KOUCHI, Yuko HIRAMITSU, Hiroaki IWATA, Yasuo KITAJIMA
  European journal of dermatology: EJD 07/2009; 19(5):509-11. · 2.53 Impact Factor
• Article: IgG from patients with bullous pemphigoid depletes cultured keratinocytes of the 180-kDa bullous pemphigoid antigen (type XVII collagen) and weakens cell attachment.

  Hiroaki Iwata, Naoko Kamio, Yumi Aoyama, Yukari Yamamoto, Yoshiaki Hirako, Katsushi Owaribe, Yasuo Kitajima
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  ABSTRACT: We have shown that binding of bullous pemphigoid (BP)-patient IgG (BP-IgG) causes the internalization of BP180 from the cell membrane. This study examined whether BP-IgG treatment can deplete cultured keratinocytes of BP180, how it affects cellular levels of alpha6 and beta4 integrins (by western blot analysis using monoclonal antibodies to these antigens), and whether it reduces adhesion of cells to the culture dish (by a vibration detachment assay). All BP-IgG or BP sera with high values of BP180-ELISA from 18 BP patients before and after oral corticosteroid treatment showed dramatically decreased BP180 in cells after 6 hours of BP-IgG stimulation, whereas alpha6 and beta4 integrin levels were not decreased. Even IgG from patients in whom oral corticosteroid had suppressed active blistering could deplete cells of BP180, as long as sera retained a high value of BP180-ELISA. On the other hand, reduction of cell BP180 content increased detachment of cells from the dish. These results suggest that BP-IgG reduces hemidesmosomal BP180 content, weakening the adhesion of hemidesmosomes to the lamina densa. In the presence of BP180 deficiency, inflammation generated by BP180 immune-complex formation might then tear the weakened lamina lucida, and this could lead to generation of the BP-specific split at the lamina lucida.
  Journal of Investigative Dermatology 02/2009; 129(4):919-26. · 6.31 Impact Factor
• Article: Cicatricial pemphigoid with prominent alopecia.

  Hiroaki Iwata, Yumi Aoyama, Chikako Esaki, Yasuo Kitajima
  European journal of dermatology: EJD 17(4):338-9. · 2.53 Impact Factor