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K Gomi

Publications and source records attributed to K Gomi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Synthesis and antitumor activity of duocarmycin derivatives: A-ring pyrrole compounds bearing beta-(5',6',7'-trimethoxy-2'-indolyl)acryloyl group.

A series of A-ring pyrrole derivatives of duocarmycin bearing beta-(5',6',7'-trimethoxy-2'-indolyl)acryloyl group were synthesized, and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. New Seg-B analogues bearing beta-(5',6',7'-trimethoxy-2'-indolyl)acryloyl group containing double bond as spacer had lower peripheral blood toxicity than the derivatives bearing 5',6',7'-trimethoxyindole-2'-carboxyl group in Seg-B of the natural type. Moreover, most of them exhibited potent antitumor activity against in vivo murine tumor models.

Animals↗
PubMed2000

Synthesis and antitumor activity of duocarmycin derivatives: modification at C-8 position of A-ring pyrrole compounds bearing the simplified DNA-binding groups.

A series of the 8-O-substituted A-ring pyrrole derivatives of duocarmycin bearing the simplified DNA-binding moieties such as cinnamoyl or heteroarylacryloyl groups were synthesized, and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. In addition, the stability of the 8-O-substituted analogues in aqueous solution and the conversion to their active form (cyclopropane compound) from the 8-O-substituted analogues in mice or human serum were examined. The 8-O-substituted A-ring pyrrole derivatives bearing the simplified DNA-binding moieties showed remarkably potent in vivo antitumor activity and low peripheral blood toxicity compared with the 8-O-substituted A-ring pyrrole derivatives having the trimethoxyindole skeleton in segment-B (Seg-B), which were equal to 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxycinnamates and 4'-methoxy-beta-heteroarylacrylates. Moreover, among 8-O-substituted analogues, several compounds can be chemically or enzymatically converted to their active form in human serum. This result indicated that new 8-O-substituted derivatives were different prodrugs from KW-2189 and 8-O-substituted analogues being the same type of prodrug as KW-2189.

Animals↗
PubMed2000

Population dynamics of Tetranychus kanzawai (Acari: Tetranychidae) on hydrangea.

The seasonal occurrence of Tetranychus kanzawai Kishida populations on hydrangea (Hydrangea macrophylla) was studied at two different localities in Ibaraki, Japan, during a three-year period. There were two types of seasonal population trends: one with a population peak from May to June, and the other with the spring peak in June and the autumn peak in September-October. Each year the populations on hydrangea plants abruptly declined just after the spring peak. Predators showed a delayed density-dependent numerical response. The population crashed even in the absence of predators, suggesting that the predators had nothing to do with the June decline. Furthermore, the rate of development from larva to adult and the fecundity in adult females on detached hydrangea leaves decreased markedly just prior to the abrupt decline in density in June. Consequently, seasonal changes in plant quality (perhaps influenced by secondary compounds) seem to contribute to the drastic decline of T. kanzawai density on hydrangea in June.

Animals↗
PubMed2000

Molecular cloning and characterization of a transcriptional activator gene, amyR, involved in the amylolytic gene expression in Aspergillus oryzae.

A gene, designated amyR, coding for a transcriptional activator involved in amylolytic gene expression has been cloned from Aspergillus oryzae by screening for a clone that enabled to reverse the reduced expression of the alpha-amylase gene (amyB) promoter. amyR encodes 604 amino acid residues of a putative DNA-binding protein carrying a zinc binuclear cluster motif (Zn(II)2Cys6) belonging to the GAL4 family of transcription factors. The amyR gene disruptants showed a significant restricted growth on starch medium and produced little of the amylolytic enzymes including alpha-amylase and glucoamylase compared with a non-disruptant, indicating that amyR is a transcriptional activator gene involved in starch/maltose-induced efficient expression of the amylolytic genes in A. oryzae. In addition, sequencing analysis found that amyR, agdA (encoding alpha-glucosidase), and amyA (encoding alpha-amylase), are clustered on a 12-kb DNA fragment of the largest chromosome in A. oryzae, and that amyR is about 1.5 kb upstream of agdA and transcribed in the opposite direction. Furthermore, transcriptional analysis revealed that the amyR gene was expressed in the presence of glucose comparable to the level in the presence of maltose, while the amylolytic genes were transcribed at high levels only in the presence of maltose.

Amino Acid Sequence↗
PubMed2000

[Hepatitis B virus gene mutations in the sera of three patients with coexisting hepatitis B surface antigen and anti-surface antibody].

We analyzed gene mutations in the Hepatitis B virus of three virus carriers with coexisting Hepatitis B surface(HBs) antigen and anti-HBs antibody. Viral DNAs were extracted from sera and the pre-S, S and X(including core promoter and pre-core region) regions were amplified by PCR, and sequenced. Case 1 and Case 2 were positive for HBe antigen, while Case 3 was negative. All three cases were positive for HBe antibody and HBV DNA. In the S gene region, various point mutations were detected in all three cases. Mutations were clustered in the first hydrophilic loop region(codon 47-46) essential for the secretion of surface antigen. A few mutations were detected in 'a' loop(codon 124-147) of the S gene. None of the cases had an amino acid substitution of codon 145 of the S gene that is reported to be responsible for weak recognition by the HBs antibody. These data suggest the existence of hyper-variable sequence in S region, or otherwise result of low-fidelity of Taq DNA polymerase-reaction. Case 1 possessed a point mutation, T to C at nucleotide position 1753, in the region overlapping the coding region of the X gene and the CCAAT/enhancer binding protein(C/EBP) binding region within the core promoter region. Case 2 possessed both a large deletion(129 bp) in the pre-S1 and in-frame deletions of 15 and 27 bp in the pre-S2 region. Case 3 had an in-frame deletion of 30 bp in the pre-S2 region, and a point mutation in precore region. The point mutation, G to A at a nucleotide position 1986, converts Trp(TGG) to a stop codon TAG, and may contribute the fulminant hepatitis. These results suggest that the mutations in the pre-S, the core promoter, or the X gene may imply coexistence of the HBs antigen and antibody after seroconversion, while the point mutations in the S region are not likely to be responsible for the HBV escape mutant.

Adult↗
PubMed2000

[Genome analysis of Helicobacter pylori by pulsed-field gel electrophoresis].

The molecular epidemiology of total 121 isolates of Helicobacter pylori was analyzed by pulsed-field gel electrophoresis method with restriction enzyme Spe I. Seventy-seven isolates were separated from the clinical samples, 36 isolates from pyloric antrum and the body of stomach of 18 patients and 8 isolates from pyloric antrum of 4 patients that include one colony before and after sterilizing treatment to each patient. Seventy-five in 77 isolates showed different genomic types respectively, and the other 2 isolates had the same genomic type and were suspected to be caused by intersective infection of medical workers or the instruments that used in examination because they were from patients who were examined by gastric microscope in same time and same laboratory. In isolates from 4 patients who were treated by sterilizing method, 2 patients showed same genomic types with that observed before the treatment, and one patient showed an incomplete treatment because the genomic type of its colony was is similar, and another patient could be infected again because its isolates showed different genomic type. In 18 patients whose isolates were separated from pyloric antrum and body of the stomach respectively to each person, isolates of 3 patients showed different genomic types in the two different part of stomach indicating that they had two and more clones of H. pylori.

Cloning, Molecular↗
PubMed2000

CTLA-4 gene polymorphism in Japanese patients with rheumatoid arthritis.

OBJECTIVE: To examine whether CTLA-4 gene confers susceptibility to rheumatoid arthritis (RA) in Japanese. METHODS: We investigated the distribution of a CTLA-4 gene polymorphism in 85 Japanese patients with RA and 200 controls. An A/G transition at position 49 of exon 1 was analyzed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. The patients were also analyzed with respect to HLA-DR status. HLA-DR typing was performed by PCR sequence-specific oligonucleotide typing. RESULTS: The distribution of genotype frequencies differed between RA and controls (chi-squared 8.63, 2 df, p = 0.013). The CTLA-4 AG genotype occurred more frequently in patients with RA (59 vs 44%), and the presence of at least one G allele (GG or AG) conferred an odds ratio of 2.53 (95% CI 1.74-3.32). When the patients were analyzed with respect to HLA-DR status, this association was restricted to patients carrying the susceptible HLA allele (HLA-DRB1*0405). CONCLUSION: The CTLA-4 gene is associated with Japanese patients with RA carrying the susceptible HLA allele.

Abatacept↗
PubMed2000

Rapid detection of homologously integrated DNA fragments and accurate quantitation of their copy number in transgenic Aspergillus oryzae by PCR.

A simple and rapid method for the analysis of artificially introduced DNA fragments has been developed using competitive PCR and long and accurate PCR. The locus and the copy number of the DNA fragments in each Aspergillus oryzae transformant could be detected more rapidly and accurately by this method than by the conventional Southern hybridization method.

Journal Article↗
PubMed1999

CTLA-4 gene polymorphism may modulate disease in Japanese multiple sclerosis patients.

Multiple sclerosis (MS) is widely believed to have a T-cell-mediated autoimmune etiology. The CTLA-4 gene is a strong candidate for involvement in autoimmune diseases because it plays an important role in the termination of T-cell activation. To examine the genetic association of the CTLA-4 gene locus with MS, we analyzed the CTLA-4 gene exon 1 A/G polymorphism in 74 Japanese MS patients and 93 controls. We also investigated the possible interactions of the CTLA-4 gene polymorphism with clinical course and severity, with MRI findings, with another genetic marker-HLA antigens, and with oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). The CTLA-4 exon 1 polymorphism was similar between MS patients and controls. Conversely, clinical disability was significantly more severe in AA homozygous patients than in the other patients, and the allele frequency and the phenotype frequency of the A allele were significantly higher in patients with severe-grade MRI findings of cerebral white matter than in patients with mild-grade MRI findings. The allele frequency and the phenotype frequency of the A allele were significantly higher in patients with OCB than in patients without. This CTLA-4 polymorphism may modulate the prognosis of patients with MS and may be relevant to generation of OCB in the CSF.

Abatacept↗
PubMed1999

Synthesis and antitumor activity of water-soluble duocarmycin B1 prodrugs.

The water-soluble duocarmycin B1 prodrugs such as glycoside 3, phosphate 4 and carbamate 5 were synthesized for improving biological and pharmaceutical profiles of duocarmycin. Among these prodrugs, N-methylpiperazinylcarbamoyl derivative 5 exhibited potent antitumor activity against several human tumors in vivo.

Animals↗
PubMed1999

Direct proteasome inhibition by clasto-lactacystin beta-lactone permits the detection of ubiquitinated p21(waf1) in ML-1 cells.

The ubiquitin proteasome pathway regulates the expression of major cellular regulatory proteins. The ubiquitin proteasome system has been demonstrated to be involved in the expression of the cyclin kinase inhibitor, p21. Ubiquitinated p21 is degraded immediately by 26S proteasome, therefore, the detection of p21 is difficult. We report here an improvement for the detection of ubiquitinated p21 using a proteasome inhibitor, clasto-lactacystin beta-lactone. A p21-enriched cell lysate is obtained by pretreating the cells with deferoxamine to induce p21 mRNA expression followed by treatment with 1x10(-6) M beta-lactone. The concentration of p21 from the cell lysate was performed using an anti-p21 antibody crosslinked to protein G Sepharose. Ubiquitinated p21 was detected on Western blots of the concentrated sample using an anti-ubiquitin antibody. This detection system will be used for further analysis of the regulation of p21 ubiquitination.

Acetylcysteine↗
PubMed1999

Radiotherapy following mastectomy: indication and contraindication of chest wall irradiation.

PURPOSE: To determine in which cases radiotherapy of the chest wall following mastectomy is indicated, based on the local recurrent rate in patients with locally advanced breast cancer. METHODS AND MATERIALS: From 1984 until 1994, 105 patients who had four or more histopathologically confirmed axillary nodes metastases, or T3-4Nany, were subjected to mastectomy and were administered radiotherapy postoperatively using the hockey-stick field, which included the ipsilateral supraclavicular fossa and internal mammary nodes, except the chest wall. Median age was 51 years old (range, 23 to 82 years old). Eighty-five patients underwent radical mastectomy, 18 modified radical mastectomy, and 2 extended radical mastectomy. Fraction size was 2 Gy/day, the weekly fraction size was 10 Gy and the total dose ranged from 44 Gy to 54 Gy (median 50 Gy). Seventy-four patients were administered adjuvant chemotherapy, and 61 patients were administered hormone therapy. RESULTS: The 5-year disease-free survival rates of the whole study population were 66%. The 5-year chest wall recurrence rates were 10%. The 5-year chest wall recurrence rates of the patients who had no vascular invasion (n = 19) and the patients who had definite vascular invasion (n = 38) were 0% and 24%, respectively (p = 0.036). All the patients who presented chest wall recurrence had four or more axillary nodes metastases. Nine of the 10 patients who presented chest wall recurrence had definite vascular invasion, while there was no information about vascular invasion for the remaining patient. Factors such as age, pathological subtypes, tumor location, estrogen receptors, extent of resection, chemotherapy, and hormone therapy did not influence the development of chest wall recurrence. CONCLUSION: Among patients with breast cancer who have four or more positive axillary nodes or T3-4Nany, those who have no vascular invasion or less than 4 axillary nodes metastases do not need to be subjected to chest wall irradiation after radical mastectomy.

Adult↗
PubMed1999

Molecular and enzymic properties of recombinant 1, 2-alpha-mannosidase from Aspergillus saitoi overexpressed in Aspergillus oryzae cells.

For the construction of an overexpression system of the intracellular 1,2-alpha-mannosidase (EC 3.2.1.113) gene (msdS) from Aspergillus saitoi (now designated Aspergillus phoenicis), the N-terminal signal sequence of the gene was replaced with that of the aspergillopepsin I (EC 3.4.23.18) gene (apnS) signal, one of the same strains as described previously. Then the fused 1, 2-alpha-mannosidase gene (f-msdS) was inserted into the NotI site between P-No8142 and T-agdA in the plasmid pNAN 8142 (9.5 kbp) and thus the Aspergillus oryzae expression plasmid pNAN-AM1 (11.2 kbp) was constructed. The fused f-msdS gene has been overexpressed in a transformant A. oryzae niaD AM1 cell. The recombinant enzyme expressed in A. oryzae cells was purified to homogeneity in two steps. The system is capable of making as much as about 320 mg of the enzyme/litre of culture. The recombinant enzyme has activity with methyl-2-O-alpha-d-mannopyranosyl alpha-D-mannopyranoside at pH 5.0, while no activity was determined with methyl-3-O-alpha-D-mannopyranosyl alpha-D-mannopyranoside or methyl-6-O-alpha-D-mannopyranosyl alpha-D-mannopyranoside. The substrate specificity of the enzyme was analysed by using pyridylaminated (PA)-oligomannose-type sugar chains, Man9-6(GlcNAc)2-PA (Man is mannose; GlcNAc is N-acetylglucosamine). The enzyme hydrolysed Man8GlcNAc2-PA (type 'M8A') fastest, and 'M6C' {Manalpha1-3[Manalpha1-2Manalpha1-3(Manalpha1-6) Manalpha1-6]Manbeta1- 4GlcNAcbeta1-4GlcNAc-PA} slowest, among the PA-sugar chains. Molecular-mass values of the enzyme were determined to be 63 kDa by SDS/PAGE and 65 kDa by gel filtration on Superose 12 respectively. The pI value of the enzyme was 4.6. The N-terminal amino acid sequence of the enzyme was GSTQSRADAIKAAFSHAWDGYLQY, and sequence analysis indicated that the signal peptide from apnS gene was removed. The molar absorption coefficient, epsilon, at 280 nm was determined as 91539 M-1.cm-1. Contents of the secondary structure (alpha-helix, beta-structure and the remainder of the enzyme) by far-UV CD determination were about 55, 38 and 7% respectively. The melting temperature, Tm, of the enzyme was 71 degrees C by differential scanning calorimetry. The calorimetric enthalpy, DeltaHcal, of the enzyme was calculated as 13.3 kJ.kg of protein-1. Determination of 1 g-atom of Ca2+/mol of enzyme was performed by atomic-absorption spectrophotometry.

Amino Acid Sequence↗
PubMed1999

Nerve growth factor modifies the expression of inflammatory cytokines by mast cells via a prostanoid-dependent mechanism.

Nerve growth factor (NGF) is well recognized to have a number of potent effects on mast cells, including increasing mast cell numbers in vivo and inducing mast cell degranulation in vitro. More recently, NGF has been demonstrated to induce PGD2 production by mast cells through the induction of mast cell cyclooxygenase expression. We have observed that NGF at doses as low as 10 ng/ml will induce IL-6 production and inhibit TNF-alpha release from rat peritoneal mast cells in the presence of lysophosphatidylserine as a cofactor. NGF synergizes with LPS treatment of peritoneal mast cells (PMC) for the induction of IL-6. Examination of the mechanism of this phenomenon has revealed that NGF can induce both rat PMC and mouse bone marrow-derived cultured mast cells to produce substantial levels of PGE2. This response is maximal at later time points 18-24 h after NGF activation. The ability of NGF to induce PGE2 is not dependent on mast cell degranulation. Other stimuli capable of inducing IL-6, such as LPS, do not induce production of this prostanoid. Inhibition of cyclooxygenase activity by PMC using either flurbiprofen or indomethacin inhibited both the NGF-induced PGE2 synthesis and the NGF-induced alterations in TNF-alpha and IL-6 production. These results suggest a role for mast cell-derived prostanoids in the regulation of local inflammatory responses and neuronal degeneration after tissue injury involving induction of NGF production.

Animals↗
PubMed1999

New water-soluble duocarmycin derivatives: synthesis and antitumor activity of A-ring pyrrole compounds bearing beta-heteroarylacryloyl groups.

A series of A-ring pyrrole compounds of duocarmycin bearing 4'-methoxy-beta-heteroarylacryloyl groups were synthesized and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. Most of the 4'-methoxy-beta-heteroarylacrylates displayed in vitro anticellular activity equivalent to that of 4'-methoxycinnamates. Among the 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxy-beta-heteroarylacrylates, compound 15b having a (4-methoxy-3,5-pyrimidinyl)acryloyl as segment-B (Seg-B) showed remarkably potent in vivo antitumor activity and low peripheral blood toxicity compared with the A-ring pyrrole derivatives having the trimethoxyindole skeleton in Seg-B, which were equal to 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxycinnamates. Moreover, these 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxy-beta-heteroarylacrylates had high aqueous solubility.

Adenocarcinoma↗
PubMed1999

Purification and characterization of a new enzyme, N-alkylglycine oxidase from Cladosporium sp. G-10.

A new enzyme, N-alkylglycine oxidase, was isolated from a soil mold, Cladosporium sp. G-10. This protein, which was purified to near homogeneity by ammonium sulfate precipitation followed by successive column chromatography on phenyl-Sepharose, DEAE-Sepharose and Sephadex G-200, was a single polypeptide with a molecular mass of 52,000. In the presence of O2 and H2O, this enzyme acted on some N-alkylglycine derivatives, such as N epsilon-carboxymethyllysine, N-carboxymethyl-6-aminocaproic acid, sarcosine and N-ethylglycine, and produced corresponding N-alkylamine, glyoxylic acid and H2O2. This enzyme had optimum activity at 30 degrees C, pH 8-10, and was most inhibited by ZnSO4, pCMB, iodoacetic acid, and SDS.

Amino Acid Oxidoreductases↗
PubMed1999

A novel histone variant localized in nucleoli of higher plant cells.

Immunofluorescence staining with antisera raised against p35, a basic nuclear protein that accumulates in the pollen nuclei of Lilium longiflorum, specifically stained the nucleoli in interphase nuclei of somatic tissues, including root and leaf, and in pachytene nuclei during meiotic division, whereas antisera raised against histone H1 uniformly stained the entire chromatin domain with the exception of the nucleoli in these nuclei. Further, p35-specific antisera stained the nucleoli in root and leaf nuclei of the monocotyledonous plants Tulipa gesneriana, Allium cepa and Triticum aestivum and of the dicotyledonous plants Vicia faba and Nicotiana tabacum. Thus, these novel antisera stained the nucleoli in cells of all higher plants examined, although the staining patterns within nucleoli were somewhat different among plant species and tissues. The full-length cDNA of p35 was cloned on the basis of the partial amino acid sequence. The deduced amino acid composition and amino acid sequence of p35 indicate that this nucleolar protein is a novel variant of histone Hl. Further, p35 was strongly bound to ribosomal DNA in vitro. The results of immunoblotting of histones extracted from each tissue of the various plant species with the nucleolus-specific antibodies also suggested the conservation of similar epitope(s) in both mono- and dicotyledonous plants. From these results, it is suggested that similar variants of histone Hl are specifically distributed in the nucleoli of all plant species and help to organize the nucleolar chromatin.

Amino Acid Sequence↗