Search PubMed⌕ Search

Biomedical subjects

K Hanada

Publications and source records attributed to K Hanada.

At least 199 records · Page 11Linked to original sources
PubMed1995

Nucleotide sequence analysis of two nuclear inclusion body and coat protein genes of a sweet potato feathery mottle virus severe strain (SPFMV-S) genomic RNA.

Recombinant DNA molecules containing cDNA of a sweet potato feathery mottle virus severe strain (SPFMV-S) RNA genome were constructed and the partial nucleotide sequences were determined for three DNA inserts, which cover 4-2 kb from the 3'-terminus excluding the poly (A) tail. This region of the genome consists of an open reading frame of 1340 amino acids (a.a.) and a 3'-non-translated region of 224 nucleotides. The protein products expected were 6K2 (53 a.a.), NIa (435 a.a.), NIb (521 a.a.) and CP (315 a.a.). Among NIa, NIb and coat proteins, the NIb protein was found to be the most conserved (59-68%) when compared to the corresponding proteins of other distinct potyviruses.

Amino Acid Sequence↗
PubMed1995

Possible role of 1,25-dihydroxyvitamin D3-induced metallothionein in photoprotection against UVB injury in mouse skin and cultured rat keratinocytes.

Previously cadmium chloride was successfully used to prevent sunburn cell (SBC) induction in mouse skin in vivo and to promote human cell survival in vitro after UVB exposure, indicating a protective effect of cadmium-induced metallothionein (MT) with the property of anti-oxidant action. Although cadmium is a potent inducer of MT, the cytotoxic metal is not available for clinical use. The aim of this study is to affirm MT gene expression by the active for of vitamin D3, 1,25-dihydroxyvitamin D3, [1,25(OH)2D3] in cultured keratinocytes and examine in vivo and in vitro the photo-protective effects of 1,25(OH)2D3. Northern hybridization with human MT-IIa cDNA showed a significant increase in the gene expression of MT in the cells treated with 1,25(OH)2D3. Intraperitoneal injection and topical application of 1,25(OH)2D3 caused a significant reduction in SBC formation in mouse skin after UVB administration. The experiment showed the existence of an optimum level of 1,25(OH)2D3 for reducing photodamage. The cells exposed to 1,25(OH)2D3 showed increased tolerance (cell survival) to UVB injury. 1,25(OH)2D3-induced MT may act as a radical scavenger in oxygen-mediated UV injury including SBC formation in the skin. These results indicate that 1,25(OH)2D3 may be practically applied to humans for the purpose of photoprotection.

Animals↗
PubMed1995

A Chinese hamster ovary cell mutant defective in the non-endocytic uptake of fluorescent analogs of phosphatidylserine: isolation using a cytosol acidification protocol.

Transmembrane movement of phosphatidylserine (PS) and various PS analogs at the plasma membrane is thought to occur by an ATP-dependent, protein-mediated process. To isolate mutant CHO cells defective in this activity, we first obtained conditions which inhibited the endocytic, but not the non-endocytic pathway of lipid internalization since PS may enter cells by a combination of these two pathways. We found that acidic treatment of cells, which blocks clathrin-dependent endocytosis, enhanced the energy-dependent uptake of 1-palmitoyl-2-(6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl -sn- glycero-3-phosphoserine (C6-NBD-PS) in CHO cells from donor vesicles (liposomes) by about twofold. Control experiments demonstrated that the enhanced uptake of C6-NBD-PS at acidic pH was not due to: (a) an increase in the capacity of the plasma membrane to incorporate C6-NBD-PS from the donor vesicles; (b) a decrease in the rate of loss of C6-NBD-PS from the cells; or (c) fusion or engulfment of the donor vesicles. When cytosolic acidification (to pH 6.3) was imposed without acidification of the extracellular medium, C6-NBD-PS uptake by intact cells was increased by about 50% compared to control values determined in the absence of acidification. These results suggested that a protein and energy dependent system(s) for transbilayer movement of the fluorescent PS was stimulated by cytosolic acidification. A screening method for mutant cells defective in the non-endocytic uptake of fluorescent PS analogs with replica cell colonies at acidic pH was then devised. After selection of mutagenized CHO-K1 cells by in situ screening, we obtained a mutant cell line in which uptake of fluorescent PS analogs was reduced to about 25% of the wild type level at either pH 6.0 or 7.4. Control experiments demonstrated that the reduced uptake of fluorescent PS analogs in the mutant cells was unrelated to multidrug resistance, and that endocytosis of another plasma membrane lipid marker occurred normally in the mutant cells. These results suggested that a non-endocytic pathway responsible for uptake of fluorescent PS analogs was specifically affected in the mutant cells.

4-Chloro-7-nitrobenzofurazan↗
PubMed1995

Successful treatment of dark-colored epidermal nevus with ruby laser.

The pulsed ruby laser has a selective thermolytic effect. Recently, it has been available for the treatment of superficial pigmented disorders. We studied 5 cases of epidermal nevus treated with the pulsed ruby laser. In comparison with the usual methods including electrocautery, cryotherapy and skin abrasion, ruby laser therapy is an excellent tool due to technological ease and rapid improvement. Depigmentation after treatment in 2 cases was the only side effect of this therapy. Bose cases had a dark pigmentation of the skin. Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.

Adolescent↗
PubMed1995

Stimulation of endosteal bone formation by systemic injections of recombinant basic fibroblast growth factor in rats.

In vivo effects of basic fibroblast growth factor (bFGF) on bone formation was examined in rats. Daily systemic injections of 100 micrograms/kg bFGF for 7 days caused a marked stimulation of endosteal bone formation in both cortical and secondary cancellous bone areas. Histological examinations revealed that the sequence of responses to the injections of bFGF consisted of three phases: an early increase in the number of preosteoblastic cells over the osteoblastic cell layer (days 1-3), recruitment of osteoblasts from preosteoblastic cells (days 3-5), and an increase in new bone formation (days 5-7). These histological changes in the endosteum correlated closely with histomorphometrical parameters of bone formation, and the endosteal mineral apposition rate was almost unaffected during the initial 4 days but was markedly enhanced after this period. Immunohistochemical examinations using antitransforming growth factor (TGF)-beta 1 antibody demonstrated that immunostaining of preosteoblastic cells for TGF-beta already increased 1 day after bFGF treatment. Distribution of TGF-beta in osteoblasts and bone matrices began to increase on day 3, and all the osteoblasts and new bone matrices were intensively immuno-stained on day 7. These results demonstrate that systemic injections of bFGF in rats stimulate endosteal bone formation, and that the stimulation of bone formation is preceded by an initial increase in preosteoblastic cells with later recruitment of osteoblasts from these cells. Because the distribution of TGF-beta in the endosteal cells is increased by bFGF, the effect of bFGF may at least in part be mediated by TGF-beta. However, the precise mechanism of action of bFGF on bone formation remains to be clarified.

Animals↗
PubMed1995

Expression of the proliferative cell nuclear antigen (PCNA) in adenocarcinoma of the gallbladder, and its relationship to prognosis.

Proliferative cell nuclear antigen (PCNA) has been correlated with degree of differentiation in some tumours, but information on PCNA expression in adenocarcinoma of the gallbladder is currently limited. Therefore, we examined PCNA expression in adenocarcinoma of the gallbladder, and its relationship to prognosis. The expression of PCNA was studied by immunohistochemistry in 70 formalin-fixed, paraffin-embedded specimens of surgically removed adenocarcinomas of the gallbladder. The percentage of stained nuclei was recorded, and the PCNA-labelling index (LI) was expressed as the ratio of labelled nuclei to the total number of nuclei counted. In all histological types, the PCNA-LI in the invasive zone of the tumour was higher than that in the luminal zone of the tumour (p < 0.05). The PCNA-LI showed a stepwise increase with decreasing degrees of differentiation in both the invasive and the luminal zone of the tumour (p < 0.01). In advanced adenocarcinomas, patients whose tumours had a PCNA-LI of less than 35 in the invasive zone had significantly longer survival rates than those with PCNA-LI equal to or greater than 35 (p < 0.01). Multivariate analysis, using the Cox proportional hazards model, indicated that a PCNA-LI > or = 35 in the invasive zone of the tumour was a significantly unfavourable prognostic factor (p = 0.002). The PCNA-LI of routinely processed specimens of adenocarcinoma of the gallbladder may be helpful for the evaluation of cell proliferation and prognosis.

Adenocarcinoma↗
PubMed1995

Histological observations of dental tissues using the confocal laser scanning microscope.

To investigate the time course of mineralization in undecalcified dental tissues, calcein- and tetracycline-labeled rat maxillary molar sections were stained with Villanueva bone stain en bloc, embedded in methyl-methacrylate (MMA), ground to 50 microns thickness, and observed by confocal laser scanning microscopy (CLSM). This method allowed observation of dental structures including odontoblasts, pulp cells and periodontal ligament, and dentinal tubules and enamel rods at high resolution; labeled enamel, dentine, and cementum could be observed simultaneously regardless of section thickness. CLSM permitted simultaneous observation of both the components of calcified tissue and the cellular components of dental tissues, and assessment of the mineralization time course of hard tissues labeled by tetracycline or calcein. The technique is useful for both assessing the elements composing dental structure and observing the histological dynamics by which dental structure develops.

Animals↗
PubMed1995

A novel bioactive delta lactone FD-211. Taxonomy, isolation and characterization.

During our screening program for natural product drugs effective against multidrug-resistant mammalian cells, we have discovered a new delta lactone FD-211 from the fermantation broth of Myceliophthora lutea TF-0409. FD-211 had a broad spectrum activity against cultured tumor cell lines, including adriamycin-resistant HL-60 cells.

Animals↗
PubMed1994

Regulation of mouse UBF gene by multiple growth-related control elements.

Transcription of the mouse Upstream Binding Factor (mUBF) gene, that encodes one of the essential transcription factors for ribosomal DNA transcription, starts from several nucleotides. Neither typical TATA-box nor CCAAT-box is found upstream of the transcription initiation site. In the promoter region, there are eight GC-boxes, eight AP-2 binding consensus sequences, four cAMP response elements, and several serum response element equivalent sequences. These elements appear to play a positive role for the regulation of the mUBF gene as a whole. Among serum response elements, members located between -1182 and -343 are indeed responsive to serum, suggesting their important role in the high expression of mUBF under cell growth conditions.

Animals↗
PubMed1994

High conservation of subunit composition of RNA polymerase I(A) between yeast and mouse and the molecular cloning of mouse RNA polymerase I 40-kDa subunit RPA40.

Mouse RNA polymerase I (or A) was purified from an ascites cell line MH134 to virtual homogeneity using a novel purification procedure and examined for subunit composition. In marked contrast to older purifications that reported 5-8 subunits, polymerase I was found to have 11 subunits with remarkable correspondence to those of yeasts. The cDNA encoding a 40-kDa subunit of this enzyme, designated RPA40, was isolated. It predicts a polypeptide of 355 amino acids (M(r) = 40,065) and is encoded by a single copy gene. Protein sequence analysis reveals that RPA40 is the homolog of yeast RPC40, having homology to alpha subunit of Escherichia coli RNA polymerase, yeast RPB3, and human RPB33 RNA polymerase II subunits. The high conservation of this subunit among distant eukaryotes and different RNA polymerases suggests functional importance of this protein as a core subunit.

Amino Acid Sequence↗
PubMed1994

Cloning and nucleotide sequence of a bacterial cytochrome P-450VD25 gene encoding vitamin D-3 25-hydroxylase.

The gene encoding an enzyme that catalyzes the hydroxylation at position 25 of vitamin D-3 was cloned from an actinomycete strain, Amycolata autotrophica, by use of a host-vector system of Streptomyces lividans. The amino acid sequence deduced from the nucleotide sequence revealed that this enzyme, tentatively named P-450VD25, contains several regions of strong similarity with amino acid sequences of cytochromes P-450 from a variety of organisms, primarily in the regions of an oxygen-binding site and a heme ligand pocket. Especially, P-450VD25 shows end-to-end similarity in amino acid sequence to P-450dNIR of Fusarium oxysporum and P-450SU2 of Streptomyces griseolus. The recombinant S. lividans strain containing the P-450VD25 gene on a multicopy plasmid converted vitamin D-3 in the medium into 25-hydroxyvitamin D-3 at a maximum yield of 10%.

Actinomycetales↗
PubMed1994

Structural features unique to a new 405-nucleotide satellite RNA of cucumber mosaic virus inducing tomato necrosis.

The complete nucleotide sequence of a new satellite RNA (KN-satRNA) of cucumber mosaic virus (CMV) strain KN, isolated from tomato plants showing severe necrosis, has been determined by the analysis of a full-length cDNA clone from which biologically active transcript was produced. KN-satRNA was 405 nucleotides and is the largest among the known CMV-satRNAs. Comparison of the sequence with D-CARNA5 (335 nucleotides) revealed three extensive homologous regions, which were the 5' region (position 1-80), the 3' half (position 213-405), and a middle section (position 116-177) of the molecule. The total length of the three regions covers almost the entire molecule of D-CARNA5. Thus, it is apparent that insertions would occur at two sites of D-CARNA5, positions 81-86 and 146, to evolve the larger size satRNA. These insertions did not alter the proposed secondary structure model of Q-satRNA. The in vitro transcript of the cDNA clone of KN-satRNA induced necrosis on tomato which was identical to that of native KN-satRNA. The 3'half of the RNA contained the "necrogenic consensus" sequence reported for other satRNAs, to which the pathogenicity of KN-satRNA may be attributed.

Base Sequence↗
PubMed1994

Dissociation between plasma bioactive and immunoactive ACTH concentrations in depressed patients.

Previous studies have reported dissociations between plasma cortisol and immunoactive adrenocorticotropic hormone (ACTH) concentrations in both normal controls and in patients with major depression. In order to investigate this issue further, placebo and dexamethasone (DEX) were administered to normal controls and depressed patients at 11 PM, and plasma cortisol and ACTH were measured the following morning at 7 AM. Plasma ACTH concentrations were quantitated by both immunoassay (I-ACTH) and by bioassay (B-ACTH). In 10 normal controls, DEX (0.25, 0.5, and 1.0 mg, PO, elixir) produced a dose-related suppression of cortisol, I-ACTH and B-ACTH, with all three hormones significantly suppressed by DEX (0.5 and 1.0 mg) (p < or = 0.01). In 20 depressed patients, 7 AM plasma ACTH and cortisol concentrations were assessed following a single dose of DEX (0.5 mg). Fifteen patients were classified as suppressors and five as escapers, as reflected by mean (+/- SEM) cortisol concentration of 19.9 +/- 3.0 ng/ml and 81.2 +/- 7.0 ng/ml, respectively. Mean I-ACTH concentrations were comparable in both the escapers (8.6 +/- 1.6 pg/ml) and in the suppressors (7.0 +/- 1.0 pg/ml). In contrast, the mean B-ACTH concentration was more than two-fold higher in the escapers (4.5 +/- 0.5 pg/ml) than in the suppressors (2.2 +/- 0.3 pg/ml) (p < or = 0.001). Eleven of the 20 patients received both placebo and DEX (0.5 mg) on two separate occasions. Although DEX significantly suppressed both cortisol (p < or = 0.0001) and B-ACTH (p < or = 0.01) concentrations, I-ACTH was not significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1994

The survival of rat cerebral cortical neurons in the presence of trophic APP peptides.

One function of Alzheimer amyloid protein precursor (APP) is the regulation of growth and differentiation in several types of cells, including fibroblasts, PC12 cells, and neurons. This activity is represented by a small stretch of amino acids in the center of the molecule around RERMS. The APP 17-mer peptide containing the RERMS domain supported survival and neurite extension of rat cortical neurons in a dose-dependent and sequence-specific manner. The APP fragment synthesized in Escherichia coli supported the survival and neurite extension of rat cortical neurons, whereas the mutant APP fragment lacking the 30 amino acids around the RERMS domain had drastically reduced activity to support the survival and neurite extension. The current study established APP as a neuron survival factor and determined that the sequence around RERMS is important for this function.

Alzheimer Disease↗
PubMed1994

Suppression of IgE production in unseparated spleen cell cultures.

When B cells from BALB/c mice were cultured with lipopolysaccharide (LPS) and interleukin-4 (IL-4), a large amount of IgE was detected in the culture supernatants. The IgE production from unseparated spleen cells cultured with LPS and IL-4 was less than the amount of IgE obtained from separated B cells. When syngeneic T cells were added to separated B cells cultures, which were subsequently stimulated with LPS and IL-4, less IgE was produced, as compared to cultures without T cells. The hypothesis that T cells, or factors secreted by these cells, inhibit IgE production is supported by the fact that the degree of suppression of IgE production paralleled the number of T cells added. CD8(+)-enriched T cells were slightly more suppressive than CD4(+)-enriched T cells. Addition of exogenous IL-3 was only partially suppressive. These observations suggest that IL-4 added to unseparated spleen cells in vitro stimulates B cells for IgE production and also stimulates T cells. Lymphokines secreted by these stimulated T cells may in turn act on B cells. Some of these lymphokines, such as interferon-gamma and IL-2, may have a suppressive action on IgE production.

Animals↗
PubMed1994

Melanosis Riehl-like facial pigmentation in a Japanese case of AIDS.

An AIDS patient with the cardinal complaint of severe pigmentation on the face is reported. Hyperpigmentation is an unusual symptom of AIDS. This is a Japanese patient who presented melanosis Riehl-like discoloration. The importance of pigmented lesions in patients who have not been given any anti-HIV agents has not been emphasized in the literature.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Bullous pemphigoid sera induce bullous-pemphigoid-like lesions in neonatal mice pretreated with a limited dose of ultraviolet B irradiation.

The role of bullous pemphigoid (BP) autoantibodies (Abs) in the pathogenesis of BP is unclear. Lack of a confirmed experimental animal model prevents studies of the pathogenetic role of BP Abs. We hypothesized that some alterations of BP antigens (BP Ags) will be necessary for causative binding of BP Abs to the Ags. To cause an artificial and reproducible alteration, neonatal mice were irradiated with ultraviolet B (UVB). After the irradiation of 600 mJ/cm2 of UVB, BP serum was intraperitoneally injected. When the BP sera, which recognized only the 230-kD BP Ag, or both 230- and 180-kD BP Ags, were transferred into the UVB-treated mice, erosions and vesicles appeared in 14-78% of the animals. Histopathological examination revealed subepidermal blister formation in the mice treated with UVB and BP sera. Electron microscopy demonstrated that the separation occurred at the level of the lamina lucida. Human IgG and C3 were deposited at the dermal-epidermal junction. Control animals to which healthy sera were injected after the same dose of UVB irradiation showed degeneration of the upper epidermis but no apparent dermal-epidermal cleft formation histopathologically. These results suggest that BP antibodies play a pathogenetic role in vivo. This animal model can contribute to a study of the pathogenesis of BP.

Animals↗