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K Iwatsuki

Publications and source records attributed to K Iwatsuki.

At least 55 records · Page 3Linked to original sources
PubMed2000

Dermal fibroblasts are one of the therapeutic targets for topical application of 1alpha,25-dihydroxyvitamin D3: the possible involvement of transforming growth factor-beta induction.

BACKGROUND: Transforming growth factor (TGF) -beta has been suggested to be an effective inhibitor for abnormal keratinocyte growth in psoriasis. As a majority of the secreted TGF-beta are biologically latent complexes, activation is essential for TGF-beta-mediated cellular responses in vitro and in vivo. Objectives Here we report the response of the TGF-beta regulation system to 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3], an active vitamin D3 analogue Patients/methods We studied two types of fibroblasts derived from normal and psoriatic lesional skin, using an enzyme-linked immunosorbent assay and Northern blotting techniques. RESULTS: 1,25(OH)2D3 caused a dose-dependent induction of latent and active TGF-beta1 proteins in both cell cultures. The increases were significant over 72 h, but not within 48 h after stimulation. The time course of TGF-beta1 mRNA expression showed a biphasic response consisting of early ( approximately 1 h) and late phases ( approximately 96 h) of induction. Concomitant increases of TGF-beta2 and -beta3, other mammalian isoforms, were observed in the 1,25(OH)2D3-treated cells, but the kinetics were all different. Co-incubation with metabolic inhibitors, actinomycin D and cycloheximide, revealed that the early induction of TGF-beta1 mRNA by 1,25(OH)2D3 is dependent on de novo RNA synthesis, but not on RNA stabilization or protein synthesis. It seems likely to be a transient and negligible response given the absence of TGF-beta1 protein production. The late induction of TGF-beta1 mRNA was partially blocked by adding isoform-specific antibodies to TGF-beta1, -beta2 and -beta3, indicating TGF-beta autoregulation. Despite these marked responses, there were no significant differences in the TGF-beta expression between normal and psoriatic fibroblasts. CONCLUSIONS: These results suggest that antiproliferative and anti-inflammatory effects of 1,25(OH)2D3 on psoriatic lesional skin may be mediated, at least in part, by a complex TGF-beta regulation in local dermal fibroblasts.

Administration, Topical↗
PubMed2000

Novel point mutations in the steroid sulfatase gene in patients with X-linked ichthyosis: transfection analysis using the mutated genes.

X-linked ichthyosis is caused by steroid sulfatase deficiency which results from abnormalities in its coding gene. The majority of X-linked ichthyosis patients ( approximately 90%) have complete or partial deletions of the steroid sulfatase gene. In this study, we examined the mutations of the steroid sulfatase gene in two unrelated X-linked ichthyosis patients without complete deletion of the gene. Polymerase chain reaction-single-strand conformation polymorphism and direct sequencing analyses showed that each patient has a different single base pair substitution within exon 8 encoding the C-terminal half of the steroid sulfatase polypeptide. Both mutations resulted in the transversion of functional amino acids: a G-->C substitution at nucleotide 1344, causing a predicted change of a glycine to an arginine, and a C-->T substitution at nucleotide 1371, causing a change from a glutamine to a stop codon. In vitro steroid sulfatase cDNA expression using site-directed mutagenesis revealed that these mutations are in fact pathogenic and reflect the levels of steroid sulfatase enzyme activities in each of the X-linked ichthyosis patients.

Adult↗
PubMed2000

Elastase expression by infiltrating neutrophils in gliomas.

Polymorphonuclear neutrophil elastase is a neutral protease released by activated polymorphonuclear neutrophils and plays a crucial role in maintaining host defense. However, under certain conditions, this enzyme damages normal tissue and facilitates infiltration of tumor cells. In this study, surgical specimens were obtained from the tumor core and infiltrating margin of the glioma of 12 patients with astrocytoma of varying degrees of malignancy, and the specimens were tested for the presence of elastase by immunohistochemical analysis. Polymorphonuclear neutrophil elastase was not present in the tumor core of any of the 12 cases. Elastase was expressed in areas of tumor infiltration of the brain in all four glioblastoma cases, three of the four anaplastic astrocytoma cases, and none of the four low-grade astrocytoma cases. There was a higher percentage of elastase-positive polymorphonuclear neutrophils in the infiltrating margin of tumors with greater degree of malignancy. Polymorphonuclear neutrophils are recruited to malignant gliomas, and the elastase released by these cells aids in the infiltration of gliomas.

Aged↗
PubMed2000

A novel secretory protein produced by rat spongiotrophoblast.

The placenta secretes various factors in stage- and cell-specific manners. We have identified a cDNA encoding a novel protein with 124 amino acids, which was named spongiotrophoblast specific protein (SSP). SSP is highly homologous to mouse 4311, showing 81% and 59% similarity at the nucleotide and amino acid levels, respectively. Northern blot analysis showed that SSP mRNA was first detected on Day 14 of pregnancy, peaked on Day 16, and remained elevated until term. In situ hybridization analysis showed that SSP mRNA was specifically expressed in spongiotrophoblast cells of Day 20 placenta but not in Day 12 placenta. No expression was detected from the differentiated or undifferentiated rat choriocarcinoma Rcho-1 cell line. Native SSP was detected as a 19-kDa molecule by Western blotting in cell extracts prepared from the junctional zone. SSP was predicted to be a secretory protein, because 1) a hydropathy test revealed that SSP contained an N-terminal hydrophobic region and 2) native SSP was also detected in the cultured media of junctional zone explants. To further investigate a potential signal peptide of this protein, sets of recombinant SSP were generated using a COS7 transfection system. The N-terminal amino acid sequence of secreted recombinant SSP confirmed that the N-terminal 17 amino acids had been cleaved to produce a secretory protein. Thus, we have identified and cloned a novel secretory protein, SSP, which is specifically expressed by rat spongiotrophoblast cells during the latter half of pregnancy.

Amino Acid Sequence↗
PubMed2000

Sequence analysis of the genes encoding the phosphoprotein of recent isolates of canine distemper virus in Japan.

The nucleotide sequences of the phosphoprotein (P) of canine distemper virus (CDV) strains isolated between 1992 and 1996 in Japan were determined. This is the first report of the complete sequences of the P genes of recently prevalent CDV strains. The deduced amino acid sequences of the P, C and V proteins showed that in the new Japanese isolates, these proteins have approximately 93%, 90-91% and 92% identities with those of the Onderstepoort vaccine strain, respectively. The predicted functional regions were conserved. RNA editing resulting in a shift to the open reading frame (ORF) of the V protein was shown to occur with the same efficiency in both the field isolates and vaccine strain.

Amino Acid Sequence↗
PubMed2000

Magnetic resonance imaging findings in primary amyloidosis-associated arthropathy.

The MRI findings of amyloid arthropathy associated with primary amyloidosis are presented here possibly for the first time in the literature. Two types of lesions are noted: (1) capsular and tendon lesions; these regions are thickened, hypointense and enhanced by gadolinium (Gd) on T1 weighted imaging (T1WI), and hyperintense on T2 weighted imaging (T2WI), and (2) periarticular and osseous lesions; these regions appear to be tumor-forming and hypointense on both T1WI and T2WI and are not enhanced by Gd. It is necessary to differentiate these findings from other diseases such as chondrosarcoma, rhabdomyosarcoma and chronic inflammatory lesions such as tuberculosis.

Amyloidosis↗
PubMed2000

[A case of neuro-Behçet's disease with HLA B54 and predominant cerebral white matter lesions].

We report a 55-year-old woman with neuro-Behçet's disease with HLA B54 and predominant cerebral white matter lesions. She showed a cryptogenic high fever and cerebral cortical symptoms such as perseveration, limbkinetic apraxia and dementia. CSF study showed an increase of cell count and protein and a decrease of sugar. MRI showed diffuse T2-high signal intensity mainly in the subcortical white matter of left parieto-occipital lobes and basal ganglia. Her clinical signs greatly improved after administration of prednisolone. Her HLA type was not B51 but B54. Though our patient did not completely satisfy clinical criteria for neither neuro-Behçet's disease nor Sweet's syndrome, she showed partial features of both Behçet's disease and Sweet's syndrome.

Behcet Syndrome↗
PubMed1999

Epitopes and nuclear localization analyses of canine distemper virus nucleocapsid protein by expression of its deletion mutants.

A series of nucleocapsid protein (NP)-deleted genes of the Onderstepoort strain was constructed in order to locate antigenic regions of the NP of canine distemper virus. The expression of proteins from 5'-deleted NP genes was examined in COS-7 cells by indirect immunofluorescence assay using three monoclonal antibodies (MAbs), c-5, f-5 and h-6, and a rabbit serum against NP. These MAbs reacted with two regions of NP. Amino acid residues from 1 to 80, and 337-358, were necessary and sufficient for formation of the epitopes identified by MAbs f-5 and h-6, and c-5, respectively. The proteins translated from intact or 3'-deleted genes were found to be localized in the nuclei of COS-7 cells, whereas the proteins from the 5'-deleted genes were mainly detected in the cytoplasm. These results suggested that 80 amino acid residues at the N-terminus are required for transportation of NP into the nucleus.

Animals↗
PubMed1999

Overexpression of monocyte-derived cytokines in active psoriasis: a relation to coexistent arthropathy.

An overexpression of inflammatory cytokines has been found in the lesional skin as well as peripheral blood in patients with psoriasis, although its etiological significance is not yet understood. In order to evaluate the cell type responsible for the elevated cytokines in the peripheral blood, we investigated cytokine profiles of the fractionated peripheral blood mononuclear cells (PBMCs) in 30 patients with psoriasis and 27 healthy controls. Without stimulation, higher levels of interleukin (IL)-1beta, IL-6, and IL-8 were produced by freshly isolated PBMCs from the patients than those from the controls. In the fractionated PBMCs, the monocyte-rich fractions were mainly responsible for the production of these cytokines and mRNA. The elevated levels of monocyte-derived cytokine mRNAs decreased following successful treatment with cyclosporin A. Although no correlation was found between the cytokine levels and the psoriasis area and severity index (PASI) scores, patients with arthropathy showed significantly high production levels of IL-1beta, IL-6, and IL-8. These findings suggest that monocytes are the major cell source producing inflammatory cytokines in the peripheral blood of psoriasis, and the increased cytokine levels are related to the coexistent arthropathy rather than the severity of cutaneous lesions.

Adult↗
PubMed1999

Establishment of a persistent mutant of canine distemper virus.

We produced a B95a lymphoid cell line persistently infected with canine distemper virus (CDV), in which virus-specific antigens were present in nearly 100% of cells without causing cytopathic effect. The virus recovered from this cell line was able to infect fresh B95a cells persistently, indicating that a persistent CDV was established.

Amino Acid Sequence↗
PubMed1999

Clinical trial of intrathecal administration of 5-fluoro-2'-deoxyuridine for treatment of meningeal dissemination of malignant tumors.

Intrathecal administration of 5-fluoro-2'-deoxyuridine (FdUrd) was performed in patients with meningeal dissemination of malignant tumors during the period from January 1996 to September 1998, and they were followed up until February 1999. The study population consisted of 23 patients: 12 with lung cancer, 4 with breast cancer, 2 with colon cancer, 1 with malignant lymphoma, 2 with glioblastoma and 2 with metastatic brain tumors of unknown origin. FdUrd was administered intrathecally through an Ommaya reservoir placed in the lateral ventricle initially at a dose of 1 microg twice per week, and the dose was increased to 10 microg and administration schedule was also increased every day. Headache and nuchal pain were relieved in all patients regardless of responsiveness to intrathecal FdUrd therapy as determined from the findings in the cerebrospinal fluid (CSF). Patients showed no side effects during the course of intrathecal chemotherapy except for slight nausea in two patients and dull headache in one. Sixteen of the 23 patients showed decreased cell number in the cerebrospinal fluid (CSF). Positive cytological findings in CSF became negative in 6 of the 23 patients, and the levels of CSF tumor markers were decreased in 14. Responsiveness to intrathecal administration of FdUrd was defined as 'response' when both the cell number and tumor markers were decreased in both ventricular and spinal CSF or when the cell number was decreased in cases in which the tumor markers were not detected. Overall, 16 of the 23 patients (70%) showed complete or partial responses to intrathecal FdUrd therapy as determined from CSF findings. These results demonstrated the efficacy of intrathecal FdUrd chemotherapy without apparent neurotoxicity for treatment of meningeal dissemination of malignant tumors.

Aged↗
PubMed1999

Molecular cloning and sequence analysis of the phosphoprotein (P) gene of the lapinized rinderpest virus.

We determined the nucleotide sequence of the coding region for the phosphoprotein (P) gene of the L strain of rinderpest virus (RPV). The gene encodes two overlapping open reading frames of 1521 and 531 nucleotides. Use of the first ATG would produce a P polypeptide of 507 amino acids, while use of the second ATG would produce a C polypeptide of 177 amino acids. In addition, the insertion of an extra G residue at the editing site generates an alternative mRNA potentially encoding the V protein of RPV. Homology comparisons of the P, C and V proteins among various viruses suggest that RPV is closer to measles virus (MV) than to canine distemper virus (CDV). Alignment of the sequences unique to the V protein revealed that the cysteine residues are well conserved among RPV, MV and CDV, and form a "zinc finger"-like motif.

Amino Acid Sequence↗
PubMed1999

Internalization of constitutive desmogleins with the subsequent induction of desmoglein 2 in pemphigus lesions.

Acantholytic blisters in pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are caused by a dissociation of desmosomes mediated by autoantibodies against desmoglein (Dsg) 3 and Dsg 1, respectively. The blistering occurs at the suprabasilar level in PV and at the subcorneal level in PF, which corresponds to the distribution of target antigens in the epidermis: there is a more prominent expression of Dsg 1 in the upper layer, whereas Dsg 3 is more prominent in the lower layer. To elucidate the histogenesis of acantholysis, we studied the alterations of the desmosomal components and the expression pattern of Dsg isoforms in the lesional and perilesional epidermis of pemphigus patients. The results demonstrated an internalization of the desmosomes in the lower epidermis of PV, PF and pemphigus vegetans. A similar phenomenon was induced in monolayers of keratinocytes cultured with PV sera. However, little change was observed in E-cadherin expression until acantholysis became manifest. This internalization occurred prior to overt acantholysis, and was frequently associated with the induction of Dsg 2 expression in the basilar or lower layers of the epidermis. These findings indicate an alteration of Dsg isoform expression in subclinical pemphigus lesions, which might be related to the characteristic acantholytic patterns: the suprabasilar layer in PV and the upper epidermis in PF.

Cells, Cultured↗
PubMed1999

The association of latent Epstein-Barr virus infection with hydroa vacciniforme.

Patients with hydroa vacciniforme (HV)-like eruptions and malignant potential have been reported from Asia and Mexico, and those patients frequently had an associated latent Epstein-Barr virus (EBV) infection. In order to elucidate the association of latent EBV infection with HV, we studied six children with typical manifestations of HV by detection of EBV genes and EBV-related RNAs in biopsy specimens from cutaneous lesions. Cutaneous lesions of all six children with typical HV contained EBV-encoded small nuclear RNA (EBER)+ cells in 3-10% of the dermal infiltrates, whereas no Bam HI-H, l-fragment (BHLF) mRNA, or transcripts encoding EA-D antigen, were detected. No EBER + cells were detected in other inflammatory or benign lymphoproliferative skin disorders tested. Polymerase chain reaction amplification confirmed the presence of EBV DNA sequences in five of six biopsy specimens from the patients. Latent EBV infection is associated with the development of cutaneous lesions of HV.

Burkitt Lymphoma↗
PubMed1999

Induction of transcription factor AP-2 by inflammatory cytokines in human keratinocytes.

Activator protein-2 is an important transcription factor for the activation of a number of genes. Here we report the induction of activator protein-2 in response to inflammatory cytokines such as interleukin-6 in keratinocytes. Immunoblotting and semiquantitative reverse transcriptase-polymerase chain reaction assays using normal human keratinocytes revealed that interleukin-6 caused a time- and concentration-dependent induction of activator protein-2 mRNA and protein. The increase of activator protein-2 mRNA was detected at 30 min after stimulation and that of activator protein-2 protein was at 2 h. Their levels were lower than the control levels at 24 h. The interleukin-6-dependent induction of activator protein-2 mRNA was completely blocked by adding actinomycin D, whereas it was approximately 50% affected by cycloheximide. Co-incubation with neutralizing antibodies against various inflammatory cytokines resulted in inhibition of the interleukin-6-dependent activator protein-2 induction at varying degrees, indicating an involvement of various cytokines in the activator protein-2 induction. The activator protein-2 induction was observed in keratinocytes derived from lesional skins with psoriasis or squamous cell carcinoma, and the high levels of activator protein-2 were histochemically detected in these lesions. Furthermore, a gel mobility shift assay using the nuclear extracts from interleukin-6-treated cells showed that interleukin-6 induced the functional activator protein-2 protein for the gene activation. These findings suggest a possible regulation mechanism of activator protein-2 through a complex cytokine system, which is conceivably the initial reaction leading to skin inflammation, and resultant keratinocyte growth and carcinogenesis.

Aged↗