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K Iwatsuki

Publications and source records attributed to K Iwatsuki.

At least 19 recordsLinked to original sources
PubMed1997

STAT5 activation correlates with erythropoietin receptor-mediated erythroid differentiation of an erythroleukemia cell line.

Interaction between erythropoietin (EPO) and its membrane receptor induces the proliferation and differentiation of erythroid progenitors. EPO has been shown to activate the JAK2-STAT5 pathway in various hematopoietic cell lines, although the physiological role of this pathway is unclear. We have previously shown that epidermal growth factor activates a chimeric receptor bearing the extracellular domain of the epidermal growth factor receptor linked to the cytoplasmic domain of the EPO receptor, resulting in proliferation of interleukin-3-dependent hematopoietic cells and erythroid differentiation (globin synthesis) of EPO-responsive erythroleukemia cells. In the present study, we introduced various deletion and tyrosine to phenylalanine substitution in the cytoplasmic domain of the chimeric receptor and expressed these mutant chimeras in an EPO-responsive erythroleukemia cell line, ELM-I-1. Mutant chimeric receptors retaining either Tyr343 or Tyr401 could activate STAT5, judged by tyrosine-phosphorylation of STAT5 and induction of CIS, a target gene of STAT5. These mutants were able to induce erythroid differentiation. However, a chimeric receptor containing both Y343F and Y401F mutations could not activate STAT5 nor induce erythroid differentiation. Thus, Tyr343 or Tyr401 of the EPO receptor are independently necessary for erythroid differentiation as well as STAT5 activation. Moreover, exogenous expression of dominant-negative STAT5 suppressed EPO-dependent erythroid differentiation. These findings suggest that STAT5 plays an important role in erythroid differentiation through the EPO receptor cytoplasmic domain.

Animals↗
PubMed1997

Species-specific beta-N-acetylgalactosaminylation of serum IgG proteins.

Lectin blot analysis of bovine, goat, human, rabbit and mouse serum immunoglobulin G (IgG) samples revealed that Wisteria floribunda agglutinin (WFA) binds to the heavy chains of bovine, goat and human serum IgG proteins but not those of the rabbit and mouse proteins. WFA-positive light chain bands were also detected in bovine, goat and human serum IgG samples only after the filters were treated with Arthrobacter ureafaciens sialidase. The WFA-binding to these IgG proteins was abolished by treatment of the filter with sialidase and then beta-N-acetylhexosaminidase or N-glycanase prior to incubation with the lectin. WFA-agarose column chromatography of the oligosaccharides released by hydrazinolysis from the IgG samples followed by reduction with NaB3H4 revealed that 0.15, 0.09 and 0.07% of the total oligosaccharides from bovine, goat and human serum IgG samples bind to the column, respectively. Partial characterization of WFA-positive bovine IgG oligosaccharides by Bio-Gel P-4 column chromatography suggested that the major oligosaccharide is of non-fucosylated biantennary complex-type. These results indicate that beta-N-acetylgalactosaminylation occurs to N-linked sugar chains of heavy and light chains of IgG proteins in a species-specific manner.

Animals↗
PubMed1997

Molecular and phylogenetic analyses of the haemagglutinin (H) proteins of field isolates of canine distemper virus from naturally infected dogs.

We isolated three strains of canine distemper virus (CDV)--the Ueno, Hamamatsu, and Yanaka strains--from dogs in Japan and analysed the molecular properties of their haemagglutinin (H) proteins. Immunoprecipitation of all three strains with a monoclonal antibody revealed H proteins with molecular masses of 84 kDa, which differs from the molecular mass (78 kDa) of the H protein of the Onderstepoort vaccine strain. However, after tunicamycin treatment immunoprecipitation identified H proteins of identical molecular mass (68 kDa) for all three field isolates and the vaccine strain. Sequence analysis showed nine potential sites for asparagine-linked glycosylation in the H proteins of the new isolates, in contrast to four in the H protein of the Onderstepoort strain. Thus, variation in glycosylation of the H proteins of the isolates and the vaccine strain may cause differences in antigenicity of the viruses. Sequences of the H genes showed that the new Japanese isolates have 99% identity with each other, 95% with other European and American isolates (from seals, a German dog, a ferret and large felids) and 90% with the vaccine strain. Phylogenetically, the new Japanese isolates form one cluster which is separate from recent European or American isolates, all of which are distinct from vaccine strains.

Amino Acid Sequence↗
PubMed1997

Expression of the nucleocapsid protein gene of the canine distemper virus.

We constructed a cDNA clone of canine distemper virus (CDV) encoding an entire nucleoprotein (NP) gene, by means of the reverse transcription-polymerase chain reaction (RT-PCR). The cloned NP gene was inserted into the eucaryotic expression vector, pRVSV. After transfection of the plasmid into Vero cells, we examined the expression of CDV-specific NP antigen by means of indirect immunofluorescence assay (IFA) and Western blotting, using various antibodies against NP of CDV and an antiserum against NP of measles virus. The CDV-NP specific antigen was detected in the nuclei of the cells transfected with pRV-ON, by means of IFA with antibodies specific to the NP.

Animals↗
PubMed1997

[Treatment of metastatic brain tumors from lung cancer: analysis of performance status between treatment methods].

Retrospective analysis was performed in 280 patients; 112 surgical cases and 168 non-surgical cases to determine which of three treatments, alone or in combination provides more prolonged improvement of performance status (PS: Karnofsky score) in patients with metastatic brain tumors from lung cancer. The treatments under scrutiny were surgical removal of metastatic brain tumor (S), radiation therapy (R) and chemotherapy (C). KS in the group treated with S or C showed a significantly better result than that in the non-S group or non-C group during the two-year observation period. However, R group showed no significant improvement in KS compared to that in the non-C group during the two-year period. During the first year after admission, two subgroups of S plus R and R alone showed most rapid decrease in KS. However, subgroups of S plus C and S plus R and C showed better results than other subgroups. In analyzing the changes in KS over the short period from admission to one month after treatment had been completed, the non-S group showed a significant decrease in KS, while the S group showed a slight increase in mean KS. The subgroup of R alone showed the greatest decrease in KS. Thus, retrospective analysis showed that surgical removal of a metastatic brain tumor led to improved KS for a short period and chemotherapy was useful in prolonging the duration of better Q.O.L.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Molecular cloning and characterization of a new member of the rat placental prolactin (PRL) family, PRL-like protein D (PLP-D).

The rat placental PRL family consists of molecules structurally similar to PRL and GH, and to date, seven members have been identified. During investigation of pregnancy stage-specific placental factors by the differential display method, we obtained a complementary DNA (cDNA) fragment (199 bp) encoding a peptide homologous to PRL-like protein (PLP)-C. By using the 3' and 5' rapid amplification of cDNA ends method, a full-length cDNA was cloned and tentatively named PLP-D. The cDNA encoded a mature protein of 240 amino acids, including a 29-amino acid signal sequence. PLP-D contains one putative N-glycosylation site and six cysteine residues that are highly conserved in the placental PRL family. Sequence comparison between PLP-D and other members of the placental PRL family showed that PLP-D is highly homologous to PLP-C (80%) and decidual PRL-related protein (73%). Northern blot analysis revealed that PLP-D messenger RNA (mRNA) first appeared at day 14 of pregnancy, and that its expression increased until term. In situ hybridization analysis indicated that PLP-D mRNA was specifically expressed in spongiotrophoblast cells and trophoblast giant cells of the placental junctional zone. Differentiated Rcho-1 cells also expressed PLP-D mRNA, whereas undifferentiated Rcho-1 cells did not.

Amino Acid Sequence↗
PubMed1996

Epidemiological observations on recent outbreaks of canine distemper in Tokyo area.

Recent outbreaks of canine distemper virus (CDV) infection in Tokyo area were investigated on the basis of clinical features and serological test. The affected dogs were clinically classified into two groups; dog with respiratory and gastrointestinal signs associated with central nervous system (CNS) signs, and those with CNS signs alone. Of 62 dogs examined, 34 belonged to the former and 28 to the latter. In immunoperoxidase assay, anti-Onderstepoort strain of CDV serum reacted at a low level against 2 field isolates of CDV. These results suggested the presence of different types of CDV population in the field.

Animals↗
PubMed1996

Serological analysis of canine distemper virus using an immunocapture ELISA.

As a rapid and sensitive method to detect canine distemper virus (CDV), an immunocapture enzyme-linked immunosorbent assay (ELISA) was performed. The sensitivity and specificity of the immunocapture ELISA were considered to be high enough. Virus neutralizing (VN) test was also established using the immunocapture ELISA. By using this test, the different cross VN titers between sera of dogs experimentally infected with the Onderstepoort strain and those with a field isolate of CDV were observed.

Animals↗
PubMed1996

Abnormal desmoglein expression by squamous cell carcinoma cells.

Abnormal expression of cell adhesion molecules and related proteins has been observed in various carcinoma cells. We compared expression patterns of desmosomal cadherins, E-cadherin, and cytoplasmic plaque proteins of four different human squamous cell carcinoma cell lines and in vivo squamous cell carcinoma cells with those of normal human keratinocytes. Unlike normal human keratinocytes, the squamous cell carcinoma cells, both in culture and in vivo, exhibited diminished or unusual expression of desmoglein 3 and desmoglein 1, which bear pemphigus vulgaris and pemphigus foliaceus antigens, respectively. Abnormal expression of E-cadherin and cytoplasmic plaque proteins such as desmoplakin and plakoglobin was also observed. Western blotting study demonstrated that three squamous cell carcinoma cell lines expressed two desmogleins with a predominant 150 kDa molecule, and a minor 130 kDa one. Although these molecular sizes were similar to those of cultured normal human keratinocytes, the 130 kDa desmoglein, which usually carries pemphigus antigenic epitopes, was weakly or negatively reactive with pemphigus vulgaris serum. One squamous cell carcinoma cell line showed a doublet of 140 and 145 kDa bands in addition to the 130 kDa band. All the carcinoma cell lines constantly expressed desmoglein 2 and desmoglein 3 mRNA, whereas cultured normal human keratinocytes always expressed desmoglein 1 and desmoglein 3 mRNA, with or without desmoglein 2 mRNA. These findings indicate that the squamous cell carcinoma cells revealed abnormal expression of desmoglein isoforms, which may be related to tumor cell kinetics such as cell invasion and metastasis.

Antigens↗
PubMed1995

Increase in plasma nitric oxide end products following rat cortical injury.

The changes in plasma nitric oxide (NO) end products, nitrite (NO2-) and nitrate (NO3-), were studied following cortical injury in rats. At 3 days after stereotactic cortical injury (day 3), plasma NO end products were significantly increased (P < 0.01), and decreased by day 7. This increase on day 3 was inhibited by a selective inhibitor of inducible NO synthase (NOS), aminoguanidine (100 mg/kg, i.p. on days 1 and 2, P < 0.001). The present study first demonstrated the temporary increase in plasma NO end products, which is attributable to the inducible NOS activation after cerebral injury.

Animals↗
PubMed1995

A bovine IgG heavy chain contains N-acetylgalactosaminylated N-linked sugar chains.

A 56K protein co-purified with bovine milk fat globule membrane (MFGM) proteins bound to Wisteria floribunda agglutinin (WFA) like most MFGM glycoproteins. Treatment with N-glycanase or beta-N-acetylhexosaminidase abolished the lectin binding to the protein. Amino acid sequence and immunoblot analyses revealed that the 56K protein is an IgG heavy chain. Lectin column chromatography of the oligosaccharides released by hydrazinolysis from the purified IgG heavy chains revealed that 0.08% of the total N-linked sugar chains bind to a WFA-agarose column, suggesting that they contain the beta-N-acetylgalactosaminylated structure.

Acetylgalactosamine↗
PubMed1995

Prostaglandin I1 analogues, SM-10902 and SM-10906, affect human keratinocytes and fibroblasts in vitro in a manner similar to PGE1: therapeutic potential for wound healing.

The newly synthesized prostaglandin (PG) I1 analogues, SM-10902 and SM-10906, were compared with PGE1 in terms of their biological effects on cultured normal human keratinocytes (NHKs) and human dermal fibroblasts (HDFs) in order to evaluate their therapeutic potential for cutaneous wound healing. The PGI1 analogues had a direct effect on cell proliferation of HDFs as did PGE1, but inhibited cell growth of NHKs in contrast to the stimulatory effect observed with PGE1. In contrast to NHKs stimulated with PGI1 analogues, which exhibited low levels of adenosine 3,5-cyclic monophosphate (cAMP). HDFs stimulated with these analogues responded in a dose-dependent manner with extremely high levels of cAMP. Conditioned media (CM) derived from media in which HDFs had been incubated with both the PGI1 analogues promoted NHK proliferation. HDF production of interleukin (IL)-6 increased in response to the PGI1 analogues. Since IL-6 was shown to promote cell growth of NHKs, enhancement of NHK proliferation by CM was thought to be due to IL-6 derived from HDFs stimulated with the PGI1 analogues.

Alprostadil↗
PubMed1995

Induction of the thigmotaxis in Paramecium caudatum.

Induction of thigmotaxis in Paramecium caudatum was examined. We succeeded in the induction by changing the ionic concentration and the Ja-value ([K+]/[Ca2+]1/2) of the surrounding medium. P. caudatum showed thigmotaxis stably in the solution containing a relatively high ionic concentration but a lower Ja-value. We found that the Paramecium cell touched the object with the tip of its oral groove and the cilia touching the object scarcely beat when the organism showed thigmotaxis.

Animals↗
PubMed1995

Immunohistochemical analysis of the lymphoid organs of dogs naturally infected with canine distemper virus.

The pathogenesis of acute canine distemper in three naturally infected dogs was investigated. The lymphoid organs showed atrophy without secondary follicles. The distribution of canine distemper virus (CDV) antigens was examined immunohistochemically with monoclonal antibodies specific for canine Thy-1, immunoglobulin (Ig) M, CD4, CD8, CD21 and CD45RB, and anti-measles virus nucleocapsid protein serum. The viral antigens were located in the T-cell-dependent areas and in the follicles of lymphoid organs; they were observed mainly in the Thy-1, or CD4-positive cells, but also in the CD8-, CD21-, or IgM-positive cells. The results indicated that Thy-1-positive and CD4-positive T cells serve as major target cells for CDV during the acute stage of infection.

Animals↗
PubMed1995

Differences in the expression of pemphigus antigens during epidermal differentiation.

Epidermal desmogleins with molecular weights of 130/140 kDa (Dsg3 or PVA) and 150/160 kDa (Dsg1 or DGI) are recognized by autoantibodies from patients with pemphigus vulgaris (PV) and pemphigus foliaceus (PF), respectively. In order to understand the histogenesis of both types of pemphigus, we studied the expression patterns of Dsg1 and Dsg3 during stratification of cultured keratinocytes. Monolayers of cultured normal human keratinocytes demonstrated uniform intercellular staining with PV sera. The staining pattern was distinct from the focal staining with PF sera observed only in the stratified areas. Both Dsg1 and Dsg3 proteins and their mRNA were expressed by the monolayers, whereas no production of Dsg2 (HDGC) mRNA was found. The relative ratio of Dsg3 to the total desmogleins, as determined by density on immunoblotting, decreased as the cultured keratinocytes stratified. In the completely stratified keratinocytes cultured on collagen membrane, Dsg1 became predominant, with subsequent reduction of PV antigen expression. The relative decrease of Dsg3 (PVA) during epidermal differentiation might be responsible for the induction of suprabasal acantholysis in PV.

Autoantigens↗
PubMed1995

Diversity of immunobiological functions of T-cell lines established from patients with adult T-cell leukaemia.

In order to understand the variety of HTLV-1-associated cutaneous diseases, we studied the cytological profile of HTLV-1-infected T-cell lines established from patients with adult T-cell leukaemia (ATL). Among four CD4+ cell lines, termed 16T(-), 35T(-), MH-1, and KS-2, the 16T(-) cells secreted elevated quantities of IL-4, IL-6 and IFN-gamma and expressed mRNA for each cytokine in the absence of exogenous stimulation. The 35T(-) cells secreted IL-6 and a small amount of IFN-gamma, but not IL-4. The MH-1 and KS-2 cells secreted only IL-6 in the absence of stimulation. In response to stimulation with phorbol-12-myristate-13 acetate (PMA), the 16T(-) cells produced more IL-4 and IFN-gamma, whereas the 35T(-) and MH-1 cells exhibited increased secretion of IFN-gamma, but still no IL-4 or IL-4 mRNA production. Although neither IL-4 nor IFN-gamma were found in the culture supernatant of KS-2 cells, the production of IL-4 mRNA was detected by RT-PCR. Culture supernatants from the 16T(-) and 35T(-) cells induced the expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-DR by cultured keratinocytes. This response was inhibited by pretreatment of the supernatant with anti-IFN-gamma antibodies. These results indicate that some HTLV-1-infected T-cell lines constitutively secrete various cytokines, including biologically active IFN-gamma. The diversity of immunobiological functions of the T-cell lines may be related to the variety of clinical features present in ATL patients.

Adult↗
PubMed1995

Malignant hemangioendothelioma.

BACKGROUND: The administration of interleukin-2 (IL-2) has recently been reported to be favorable for treating malignant hemangioendothelioma (MHE). METHODS: Two patients with MHE responded well to intralesional injections of recombinant IL-2 (rIL-2) without major side effects. The purpose of this study was to characterize cells infiltrating the regressing tumor following rIL-2 treatment. Immunohistochemical studies were performed on biopsy specimens taken from rIL-2-injected lesional skin. RESULTS: It was shown that CD8+ lymphocytes and CD56+ natural killer (NK) cells infiltrated at the rIL-2-injection sites, suggesting that these cells contributed to the tumor regression. In addition, MHE cells bore intercellular adhesion molecule-1 (ICAM-1) whose expression was augmented by rIL-2 injections. CONCLUSIONS: These findings suggested, that rIL-2 not only induces lymphokine-activated killer (LAK) cells and NK cells, but also facilitates these cytotoxic cells to adhere to MHE cells by enhancing ICAM-1 expression of tumor cells.

Aged↗