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Biomedical subjects

Keiji Iwatsuki

Publications and source records attributed to Keiji Iwatsuki.

At least 19 recordsLinked to original sources
PubMed2006

A novel, noninvasive diagnostic probe for hydroa vacciniforme and related disorders: detection of latency-associated Epstein-Barr virus transcripts in the crusts.

OBJECTIVE: To establish a new diagnostic method for Epstein-Barr virus (EBV)-associated cutaneous disorders. DESIGN: Skin biopsy is usually required to confirm the latent EBV infections in cutaneous lesions of EBV-associated NK/T-cell lymphoproliferative disorders, including hydroa vacciniforme (HV) and hypersensitivity to mosquito bites (HMB). We have devised a novel, noninvasive method to detect EBV-encoded small RNA (EBER), BamHI A rightward transcripts (BARTs) in the skin crusts and scales of such patients. PATIENTS: Six patients with EBV-associated cutaneous lesions were enrolled in the present study, including three patients with HV, one with HV-like eruptions and chronic active EBV infection, and two with EBV-associated cutaneous lymphoma. MAIN OUTCOME MEASURES: RNA was extracted from the crusts obtained from the cutaneous lesions by forceps, converted to cDNA, and processed for polymerase chain reaction (PCR) amplification with a specific set of primers. The PCR products were assayed by a DNA sequencer. RESULTS: Intact RNAs were successfully extracted from the crusts as well as control materials. EBER1 and BARTs RNAs were detected in all 7 crusts, and in 6 of 7 crusts of EBV-associated cutaneous diseases, respectively. One of 23 crusts from non EBV-associated diseases was positive for EBER1 RNA. The sensitivity and specificity of our assay for latent EBV infection were 100% and 95.8% for EBER1 RNA, and 85.7% and 100% for BARTs mRNA, respectively. The correct DNA sequence for EBER1 and BARTs was confirmed in the PCR products by a direct sequencing method. CONCLUSIONS: Our procedure may be of use as a biomarker for EBV-associated cutaneous lesions, including HV, HMB, and NK/T-cell lymphomas.

Adolescent↗
PubMed2006

Staphylococcal cutaneous infections: invasion, evasion and aggression.

Staphylococcal infections cause a variety of cutaneous and systemic infections, including impetigo, furuncle, subcutaneous abscess, staphylococcal scalded skin syndrome (SSSS), toxic shock syndrome (TSS) and neonatal toxic shock syndrome-like exanthematous disease (NTED), in association with microbial virulence factors. The virulence factors produced by Staphylococcus aureus have a wide array of biological properties, including disruption of the epithelial barrier, inhibition of opsonization by antibody and complement, interference with neutrophil chemotaxis, cytolysis of neutrophils, and inactivation of antimicrobial peptides. Exfoliative toxins (ETs) induce the 'acantholytic' infection of S. aureus due to the disruption of cell-to-cell cohesion, which allows the pathogenic organisms to spread within the epithelium. Furthermore, S. aureus expresses exotoxins with biological properties of superantigens that induce T-cell activation with subsequent anergy and immunosuppression. Of the S. aureus leukotoxins, Panton-Valentine leukocidin (PVL) is involved in the development of multiple furuncles with more intense erythema, particularly in healthy young adults. TSS is an acute life-threatening illness caused by TSS toxin-1 (TSST-1) and is usually classified into two categories; menstrual TSS, originally described in association with tampon use, and nonmenstrual TSS with a variety of clinical settings. NTED is a neonatal disease induced by TSST-1 although clinical symptoms are much milder than those of TSS. In TSS and NTED, the expansion of TSST-1-reactive Vbeta2-positive T cells is observed. The production of pathogenic S. aureus exotoxins and biofilm formation is regulated by the accessory gene regulator (agr) locus in the quorum-sensing signaling pathway. There is no doubt that targeting the quorum-sensing signaling pathway or anti-toxin therapy is a promising therapeutic approach supportive of primary antibiotic therapy.

Biofilms↗
PubMed2006

Pathogenic link between hydroa vacciniforme and Epstein-Barr virus-associated hematologic disorders.

OBJECTIVES: To determine the pathogenic association of latent Epstein-Barr virus (EBV) infections with both typical hydroa vacciniforme (HV) and severe HV-like eruptions, and to survey the complications and outcomes of patients. DESIGN: Case series. PATIENTS: Twenty-nine patients with HV or severe HV-like eruptions. INTERVENTIONS: In situ hybridization and immunostaining of biopsy specimens; extraction of DNA samples from cutaneous lesions and/or peripheral blood mononuclear cells for EBV DNA assay. MAIN OUTCOME MEASURES: Clinicopathologic manifestations, hematologic findings, complications, and outcomes; presence of latent EBV infection. RESULTS: T cells positive for EBV-encoded small nuclear RNA (EBER) were detected, to various degrees, in cutaneous infiltrates in 28 (97%) of 29 patients, including all 6 patients with definite HV with a positive phototest reaction, 11 of 12 patients with probable HV without evidence of photosensitivity, and all 11 patients with severe HV associated with systemic symptoms. In addition to EBER-positive T cells, many cytotoxic T lymphocytes expressing T-cell intracellular antigen 1 and granzyme B were present in the cutaneous lesions. Natural killer (NK) cells were absent or at a background level. The UV-induced cutaneous lesions showed histopathologic findings consistent with those of HV, containing many EBER-positive cells. Although no hematologic abnormalities were found in the definite and probable HV groups, the amounts of EBV DNA were increased in the peripheral blood mononuclear cells. By contrast, the severe HV group had markedly increased levels of EBV DNA associated with NK-cell lymphocytosis, and complications including chronic active EBV infection, hypersensitivity to mosquito bites, and hemophagocytic syndrome. Five patients with severe disease died of EBV-associated NK/T-cell lymphomas or hemophagocytic syndrome 2 to 14 years after onset. CONCLUSION: Both typical and severe HV are included within the spectrum of cutaneous disorders mediated by EBV-infected T cells, and the severe HV group may have overt EBV-associated NK/T-cell lymphoproliferative disorders with a frequently fatal outcome.

Adolescent↗
PubMed2006

Database of two-dimensional polyacrylamide gel electrophoresis of proteins labeled with CyDye DIGE Fluor saturation dye.

CyDye DIGE Fluor saturation dye (saturation dye, GE Healthcare Amersham Biosciences) enables highly sensitive 2-D PAGE. As the dye reacts with all reduced cysteine thiols, 2-D PAGE can be performed with a lower amount of protein, compared with CyDye DIGE Fluor minimal dye (GE Healthcare Amersham Biosciences), the sensitivity of which is equivalent to that of silver staining. We constructed a 2-D map of the saturation dye-labeled proteins of a liver cancer cell line (HepG2) and identified by MS 92 proteins corresponding to 123 protein spots. Functional classification revealed that the identified proteins had chaperone, protein binding, nucleotide binding, metal ion binding, isomerase activity, and motor activity. The functional distribution and the cysteine contents of the proteins were similar to those in the most comprehensive 2-D database of hepatoma cells (Seow et al.., Electrophoresis 2000, 21, 1787-1813), where silver staining was used for protein visualization. Hierarchical clustering on the basis of the quantitative expression profiles of the 123 characterized spots labeled with two charge- and mass-matched saturation dyes (Cy3 and Cy5) discriminated between nine hepatocellular carcinoma cell lines and primary cultured hepatocytes from five individuals, suggesting the utility of saturation dye and our database for proteomic studies of liver cancer.

Cell Line, Tumor↗
PubMed2006

Toward a comprehensive quantitative proteome database: protein expression map of lymphoid neoplasms by 2-D DIGE and MS.

Using 2-D DIGE, we constructed a quantitative 2-D database including 309 proteins corresponding to 389 protein spots across 42 lymphoid neoplasm cell lines. The proteins separated by 2-D PAGE were identified by MS and assigned to the expression data obtained by 2-D DIGE. The cell lines were categorized into four groups: those from Hodgkin's lymphoma (HL) (4 cell lines), B cell malignancies (19 cell lines), T cell malignancies (16 cell lines), and natural killer (NK) cell malignancies (3 cell lines). We characterized the proteins in the database by classifying them according to their expression level. We found 28 proteins with more than a 2-fold difference between the cell line groups. We also noted the proteins that allowed multidimensional separation to be achieved (1) between HL cells and other cells, (2) between the cells derived from B cells, T cells and NK cells, and (3) between HL cells and anaplastic large cell lymphoma cells. Decision tree classification identified five proteins that could be used to classify the 42 cell lines according to differentiation. These results suggest that the quantitative 2-D database using 2-D DIGE will be a useful resource for studying the mechanisms underlying the differentiation phenotypes of lymphoid neoplasms.

Algorithms↗
PubMed2006

Cutaneous angiolipoleiomyoma.

We describe a girl with cutaneous angiolipoleiomyoma on the buttock. The 16-year-old girl had a 2.5- x 1.5-cm subcutaneous tumor on the right buttock, which was slightly tender. The tumor appeared to be vascular and was, therefore, surgically excised. Histologically, the lesion was poorly circumscribed and was composed of differently sized blood vessels, smooth-muscle bundles, and mature adipose tissue. These histologic findings were consistent with those of angiomyolipoma, which commonly occurs in the kidney. Cutaneous angiomyolipoma, which is also known as cutaneous angiolipoleiomyoma, is a rare benign mesenchymal tumor. To our knowledge, only 16 cases have been reported in the English-language literature. In our report, we review the clinical features of 17 cases, including the current one. We point out the differences between the cutaneous and renal forms of angiomyolipoma, and conclude that the cutaneous lesion is distinct from a renal lesion in several aspects, including tuberous sclerosis complex association and immunoreactivity to both HMB-45 and MART-1.

Adolescent↗
PubMed2006

A case of infectious eccrine hidradenitis.

We report a case of "infectious" neutrophilic eccrine hidradenitis who developed papules on the upper arm and trunk. Histological findings revealed vacuolar degeneration and necrosis of epithelial cells in the eccrine sweat ducts and neutrophils that had migrated through ductal epithelium to the lumen. A microabscess was also seen in the eccrine sweat gland coil. Our patient had received no chemotherapy such as cytarabine. Gram-positive cocci were present in the lesional eccrine duct indicating an infective origin of the disease. Human beta defensin-2, one of epithelial antimicrobial peptides, was present in the lesional epidermis and eccrine duct.

Aged↗
PubMed2006

An immunostimulatory DNA sequence from a probiotic strain of Bifidobacterium longum inhibits IgE production in vitro.

The immunostimulatory oligodeoxynucleotide (ODN) BL07 (5'-GCGTCGGTTTCGGTGCTCAC-3') was identified from the genomic DNA of the probiotic strain Bifidobacterium longum BB536. ODN BL07 stimulated B-lymphocyte proliferation and induced interleukin-12 (IL-12) production in macrophage-like J774.1 cells. ODNs BL07 and BL07S (modified with phosphorothioate backbone) significantly inhibited immunoglobulin E (IgE) production and stimulated interferon-gamma (IFN-gamma) and IL-12 production, but did not affect IL-4 secretion in murine splenic cells of ovalbumin-primed BALB/c mice. These ODNs also significantly inhibited production of IgE in purified murine B cells in the presence of IL-4 and anti-CD40. The results suggest the potential of ODNs BL07 and BL07S in preventing IgE-related immune responses and the possible involvement of ODN BL07 in the antiallergic efficacy of B. longum BB536.

Animals↗
PubMed2006

Oral administration of an immunostimulatory DNA sequence from Bifidobacterium longum improves Th1/Th2 balance in a murine model.

We have reported the antiallergic activities of the immunostimulatory oligodeoxynucleotide (ODN) BL07S, identified from genomic DNA of Bifidobacterium longum BB536 from in vitro and in vivo studies. The present study evaluated the efficiency of ODN BL07S in preventing allergic responses by oral administration. Oral administration of BL07S suppressed serum ovalbumin (OVA)-specific immunoglobulin (Ig) E levels and improved the OVA-specific IgG2a/IgG1 ratio. ODN BL07S increased Th1 cytokine and decreased Th2 cytokine production in splenocytes. These results suggest that immunostimulatory ODNs are potentially associated with the antiallergic effects of probiotics.

Adjuvants, Immunologic↗
PubMed2005

The association between Staphylococcus aureus strains carrying panton-valentine leukocidin genes and the development of deep-seated follicular infection.

BACKGROUND: Panton-Valentine leukocidin (PVL) is mainly associated with necrotic suppurative lesions, such as furuncles and abscesses in the skin and subcutaneous tissue, but it has also been isolated from patients with community-acquired, severe, necrotizing pneumonia. However, the clinical manifestations of furuncles caused by PVL-producing Staphylococcus aureus and the role of patients' background are not fully understood. METHODS: We used polymerase chain reaction amplification to test for the PVL gene in 161 strains of S. aureus isolated from suppurative skin lesions. For all PVL gene-positive strains isolated from furuncles, we analyzed cutaneous manifestations, patient background characteristics, and bacteriological markers, including coagulase types, presence of the mecA gene, and toxin profiles, and we compared these results with those for PVL gene-negative strains. RESULTS: PVL genes were detected in 16 (40%) of the 40 S. aureus strains isolated from furuncles, 2 (28%) of the 7 strains isolated from carbuncles, 1 (14%) of the 7 strains isolated from abscesses, and 1 (5%) of the 20 strains isolated from folliculitis. PVL gene-positive S. aureus usually causes multiple (rather than single) furuncles, and such furuncles are usually associated with more-intense erythema around the lesions. PVL gene-positive strains were isolated from young adults without underlying diseases, whereas PVL gene-negative strains were isolated from patients with various systemic complications, including diabetes, leukemia, and autoimmune diseases. CONCLUSIONS: PVL gene-positive S. aureus strains are involved in the development of multiple furuncles with more-intense erythema, particularly in healthy young adults. An understanding of the characteristics of furuncles due to PVL gene-positive strains might be useful for preventing the development of the severe systemic infections.

Adolescent↗
PubMed2005

Proteomic study of human hepatocellular carcinoma using two-dimensional difference gel electrophoresis with saturation cysteine dye.

To identify the proteomic alterations associated with carcinogenesis of hepatocellular carcinoma (HCC), we compared the protein expression profiles of nine HCC cell lines with those of primary cultured hepatocytes established from five individuals. A differential proteomic study was performed by two-dimensional difference gel electrophoresis, in which protein samples are labeled with different fluorescent dyes and separated according to their isoelectric point and molecular weight. To label the protein samples, we used a newly developed and highly sensitive fluorescent dye, which reacts with all reduced cysteine residues of proteins. Principal component analysis based on the intensity of 1238 protein spots indicated that the HCC cells and the normal hepatocytes had distinct proteomic profiles. The Wilcoxon test was used to determine the protein spots whose intensity was differentially regulated in the HCC cells compared with the normal hepatocytes, and mass spectrometric analysis was used to identify the proteins corresponding to the spots. The proteins identified are involved in cell cycle regulation, binding to a tumor-suppressor gene product, fatty acid binding, and regulation of translation. Western blotting with specific antibodies revealed the overexpression of PCNA, EB1 and E-FABP in HCC tissues compared with noncancerous tissues. Aberrant regulation of EB1 and E-FABP has not previously been implicated in the development of HCC.

Adult↗
PubMed2005

Protein expression pattern distinguishes different lymphoid neoplasms.

To identify proteins associated with the histological subtypes of lymphoid neoplasms, we studied the proteomes of 42 cell lines from human lymphoid neoplasms including Hodgkin's lymphoma (HL; four cell lines), B cell malignancies (19 cell lines), T cell malignancies (16 cell lines), and natural killer (NK) cell lymphoma (three cell lines). The protein spots were sequentially selected by (i) Wilcoxon or Kruskal-Wallis tests to find the spots whose intensity was significantly (p <0.05) different among the cell line groups, (ii) by statistical-learning methods to prioritize the spots according to their contribution to the classification, and (iii) by unsupervised classification methods to validate the classification robustness by the selected spots. The selected spots discriminated (i) between HL cells and other cells, (ii) between the cells from B cell malignancies, T cell malignancies, and NK cell lymphoma cells, and (iii) between HL cells and anaplastic large cell lymphoma cells. Among the 31 informative protein spots, MS identified 24 proteins corresponding to 23 spots. Previous reports did not correlate these proteins to lymphocyte differentiation, suggesting that a proteomic study would identify the novel mechanisms responsible for the histogenesis of lymphoid neoplasms. These proteins may have potential as differential diagnostic markers for lymphoid neoplasms.

Amino Acid Sequence↗
PubMed2005

Defining early mycosis fungoides.

This editorial review summarizes the results of 5 meetings sponsored by the International Society for Cutaneous Lymphoma at which the clinicopathologic and ancillary features of early mycosis fungoides were critically examined. Based on this analysis, an algorithm was developed for the diagnosis of early mycosis fungoides involving a holistic integration of clinical, histopathologic, immunopathologic, and molecular biological characteristics. A novel aspect of this algorithm is that it relies on multiple types of criteria rather than just one, for example, histopathology. Before its finalization, the proposed diagnostic algorithm will require validation and possibly further refinement at multiple centers during the next several years. It is anticipated that a more standardized approach to the diagnosis of early mycosis fungoides will have a beneficial impact on the epidemiology, prognostication, treatment, and analysis of clinical trials pertaining to this most common type of cutaneous lymphoma.

Algorithms↗
PubMed2005

Eradication of Epstein-Barr virus episome and associated inhibition of infected tumor cell growth by adenovirus vector-mediated transduction of dominant-negative EBNA1.

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1), a latent viral protein consistently expressed in infected proliferating cells, is essentially required in trans to maintain EBV episomes in cells. We constructed a mutant (mt) EBNA1 and examined whether it exerted dominant-negative effects on maintenance of the viral episome thereby leading to abrogation of EBV-infected tumor cell growth. Using lymphocyte and epithelial cell lines converted with neomycin-resistant recombinant EBV (rEBV) as models, adenovirus vector-mediated transduction of mtEBNA1, but not LacZ, brought about rapid and striking reductions in rEBV-derived wild-type EBNA1 levels and viral genomic loads in converted lines of three major viral latencies. This outcome was further validated at the single-cell level by cellular loss of G418 resistance and viral signals in situ. The mtEBNA1 transduction significantly impaired growth of naturally EBV-harboring Burkitt lymphoma cells in vitro and in vivo, largely in association with the eradication of viral episomes. Expression of mtEBNA1 per se caused no detectable cytotoxicity in EBV-uninfected cells. These results indicate that mtEBNA1 can act as a dominant-negative effector that efficiently impedes the EBV-dependent malignant phenotypes in cells regardless of viral latency or tissue origin. The mutant will afford an additional therapeutic strategy specifically targeting EBV-associated malignancies.

Adenoviridae↗
PubMed2005

NK-cell neoplasms in Japan.

Neoplasms putatively originating from precursor and mature natural killer (NK) cells are rare, and their clinical features are unclear. A nationwide survey was performed in Japan to clarify the clinical features of these neoplasms diagnosed between 1994 and 1998, and data for 237 patients who met the criteria for putative NK cell-lineage neoplasms were analyzed. Among them, 11 had myeloid/NK-cell precursor acute leukemia, 15 blastic NK-cell lymphoma, 21 precursor NK-cell acute lymphoblastic leukemia, 22 aggressive NK-cell leukemia/lymphoma, 149 nasal-type NK-cell lymphoma (123 nasal and 26 extranasal) and 19 chronic NK lymphocytosis. The median overall survival time of patients with aggressive NK-cell leukemia/lymphoma was 2 months, which for chronic NK lymphocytosis was more than 8 years, and that for the other types of NK-cell neoplasms was between 6 and 22 months. Nasal NK-cell lymphoma and extranasal NK-cell lymphoma share the same histology. The age of affliction was the same, but the sex was different with males predominantly having nasal NK-cell lymphoma and females extranasal NK-cell lymphoma. Patients with extranasal NK-cell lymphoma had the tendency to exhibit a more advanced state of disease, with significantly higher International Prognostic Index and LDH levels, and significantly lower hemoglobin and platelet levels. The overall survival, however, did not differ significantly. Precursor NK-cell acute lymphoblastic leukemia and blastic NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of blastic cells in the bone marrow or peripheral blood, but there were no significant differences for affected age, gender, involved sites or prognosis. Aggressive NK-cell leukemia/lymphoma and extranasal NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of large granular lymphocytes in the bone marrow or peripheral blood and it is possible that aggressive NK-cell leukemia/lymphoma is a leukemic phase of extranasal NK-cell lymphoma. The incidence of skin involvement, however, was significantly higher for extranasal NK-cell lymphoma, suggesting that the two diseases are different. In nasal NK-cell lymphoma, Epstein-Barr virus in tumor cells was detected in all patients tested, suggesting its causative role.

Disease-Free Survival↗