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K Gomi

Publications and source records attributed to K Gomi.

At least 55 records · Page 3Linked to original sources
PubMed1999

An aureobasidin A resistance gene isolated from Aspergillus is a homolog of yeast AUR1, a gene responsible for inositol phosphorylceramide (IPC) synthase activity.

The AUR1 gene of Saccharomyces cerevisiae, mutations in which confer resistance to the antibiotic aureobasidin A, is necessary for inositol phosphorylceramide (IPC) synthase activity. We report the molecular cloning and characterization of the Aspergillus nidulans aurA gene, which is homologous to AUR1. A single point mutation in the aurA gene of A. nidulans confers a high level of resistance to aureobasidin A. The A. nidulans aurA gene was used to identify its homologs in other Aspergillus species, including A. fumigatus, A. niger, and A. oryzae. The deduced amino acid sequence of an aurA homolog from the pathogenic fungus A. fumigatus showed 87% identity to that of A. nidulans. The AurA proteins of A. nidulans and A. fumigatus shared common characteristics in primary structure, including sequence, hydropathy profile, and N-glycosylation sites, with their S. cerevisiae, Schizosaccharomyces pombe, and Candida albicans counterparts. These results suggest that the aureobasidin resistance gene is conserved evolutionarily in various fungi.

Amino Acid Sequence↗
PubMed1999

Cloning and functional analysis of the Aspergillus oryzae conidiation regulator gene brlA by its disruption and misscheduled expression.

We cloned the brlA gene from Aspergillus oryzae genomic DNA using the A. nidulans brlA gene as a probe. A 3.1-kb EcoRI-BalI genomic DNA fragment was cloned and sequenced. The deduced amino acid sequence revealed 70% identity with A. nidulans BRLA and contained two C2H2 zinc finger motifs in its carboxyl terminus, and the promoter sequence contained a 43-bp highly conserved region, indicating that the cloned gene was an A. oryzae homologue of A. nidulans brlA. Disruption of the brlA gene by homologous recombination resulted in the loss of ability to form conidiophores. These results suggest that the brlA gene of A. oryzae plays a fundamental role in controlling conidiophore development. When the brlA gene was expressed under the control of the amyB promoter in A. oryzae transformants, highly differentiated and compact colonies were observed on a solid medium. The misscheduled expression of the brlA gene in submerged culture, in which conidiation does not normally occur, caused the development of complex conidiophore structures with vesicles, phialides and conidia.

Journal Article↗
PubMed1999

Antitumor activity of KF22678, a novel thioester derivative of leinamycin.

KF22678, a novel thioester derivative of leinamycin with the 1-oxo-1,2-dithiolane-3-one moiety, was examined for anti-tumor activity, toxicity in mice and activation mechanism. KF22678 showed a broad antitumor spectrum against human carcinoma xenografts (lung, colon, ovary and prostate). The efficacy of KF22678 was significantly higher than that of cisplatin. KF22678 exhibited low cross-resistance against various drug-resistant cell lines of MDR1 or MRP overexpressing human tumors, and, in addition, exhibited more potent antitumor activity in vivo than ADM against A2780/ADM and KB/MRP xenograft. DL-Buthionine sulfoximine (BSO) pretreatment significantly reduced intracellular glutathione (GSH) level in human lung carcinoma A549 cells, leading to decrease in the cytotoxicity of KF22678, whereas the cytotoxicity of melphalan was augmented by BSO pretreatment. DNA single-strand breaks (SSB) were observed in A549 cells treated with KF22678 and bleomycin. DNA SSB induced by KF22678 was greatly reduced in the presence of BSO in the cells, whereas DNA SSB induced by bleomycin was not. In addition, the antitumor activity of KF22678 against BSO-pretreated human lung carcinoma PC-9 tumor was significantly decreased. These results suggest that the activation of KF22678 by intracellular GSH might be important for DNA SSB and antitumor activity in vitro and in vivo.

Animals↗
PubMed1999

In vitro activity of HSR-903, a new oral quinolone, against bacteria causing respiratory infections.

The in vitro activity of HSR-903, an oral quinolone, against 196 recent clinical isolates of respiratory pathogens was evaluated. HSR-903 was 2 to 32 times more active than ofloxacin, ciprofloxacin, and sparfloxacin against Staphylococcus aureus, including methicillin-resistant strains, and Streptococcus pneumoniae and was at least as active as the other quinolones against gram-negative pathogens.

Anti-Infective Agents↗
PubMed1999

Synthesis and antitumor activity of duocarmycin derivatives: a-ring pyrrole compounds bearing 5-membered heteroarylacryloyl groups.

A series of A-ring pyrrole compounds of duocarmycin bearing 5-membered heteroarylacryloyl groups (thienylacryloyl and pyrrolylacryloyl) and heteroarylcarbonyl 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 thienylacrylates displayed in vitro anticellular activity equivalent to 4'-methoxycinnamates. Among the 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of methoxy-thienylacrylates, compound 11b, having 4'-methoxy-2'-thienylacryloyl as segment-B (Seg-B), showed remarkably potent antitumor activity and low peripheral blood toxicity in vivo, which were equal to those of 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxycinnamates, compared with the A-ring pyrrole derivatives having the trimethoxyindole skeleton in Seg-B. On the other hand, the 2'-pyrrolylacrylates having a double bond as spacer showed 10(2)- to 10(3)-fold stronger anticellular activity than 2'-pyrrolecarboxylates (IC50 < 0.3 nM, 72 h-exposure). The 8-O-acetate and 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 2'-pyrrolylacrylates exhibited an antitumor effect at a lower dose compared with the 8-O-[(N-methylpiperazinyl] derivatives of 4'-methoxycinnamate (1j). Moreover, it was expected that the antitumor activity would be increased by the strength of the extra hydrogen bond formed between the nitrogen of the pyrrole amido group and DNA, owing to the increase of the number of N-methyl-2'-pyrrolecarboxamide units. However, 2'-pyrrolylacrylates having three N-methyl-2'-pyrrolecarboxamide units showed nearly equal antitumor activity to 2'-pyrrolylacrylates having only one N-methyl-2'-pyrrolecarboxamide unit.

Acrylates↗
PubMed1999

Insertion analysis of putative functional elements in the promoter region of the Aspergillus oryzae Taka-amylase A gene (amyB) using a heterologous Aspergillus nidulans amdS-lacZ fusion gene system.

Expression of the Taka-amylase A gene (amyB) of Aspergillus oryzae is induced by starch or maltose. The A. oryzae amyB gene promoter contains three highly conserved sequences, designated Regions I, II, and III, compared with promoter regions of the A. oryzae glaA encoding glucoamylase and the agdA encoding alpha-glucosidase. To identify the function of these sequences within the amyB promoter, various fragments containing conserved sequences in the amyB promoter were introduced into the upstream region of the heterologous A. nidulans amdS gene (encoding acetamidase) fused to the Escherichia coli lacZ gene as a reporter. Introduction of the sequence between -290 to -233 (the number indicates the distance in base pairs from the translation initiation point (+1)) containing Region III significantly increased the expression of the lacZ reporter gene in the presence of maltose. The sequence between -377 to -290 containing Region I also increased the lacZ activity, but its maltose inducibility was less than that of Region III. The sequence between -233 to -181 containing Region II had no effect on the expression. These results indicated that Region III is most likely involved in the maltose induction of the amyB gene expression.

Amidohydrolases↗
PubMed1999

Lack of association between CTLA-4 gene polymorphism and IDDM in Japanese subjects.

Susceptibility to insulin-dependent diabetes mellitus (IDDM) is determined by both environmental and genetic factors. The main gene associated with predisposition to IDDM is HLA. Recent studies have described linkage and association of IDDM to the CTLA-4 gene (IDDM12) in Caucasians. CTLA-4 is a candidate gene for T-cell-mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. We investigated the distribution of a CTLA-4 gene polymorphism in 110 Japanese patients with IDDM and 200 control subjects. In 84 patients, we also investigated associations between this CTLA-4 gene polymorphism and GAD65 antibody positivity. An A/G transition at position 49 of exon 1 was analyzed by the polymerase chain reaction-restriction fragment length polymorphism method. GAD65 antibody was detected using a radioligand binding assay. There was no significant difference in the distribution of CTLA-4 alleles in patients and controls and no difference was observed in prevalence of CTLA-4 alleles when GAD65 antibody-positive and -negative individuals in the IDDM groups were compared. The present study did not support an association between the CTLA-4 gene and IDDM in the Japanese population.

Abatacept↗
PubMed1999

[In vitro activity of biapenem (BIPM) against clinically isolated respiratory pathogens in 1996-1998].

The in vitro antibacterial activity of biapenem (BIPM), a new carbapenem antibiotic, was compared with those of imipenem (IPM), panipenem (PAPM), meropenem (MEPM), ceftazidime (CAZ) and piperacillin (PIPC) against 280 isolates of 9 respiratory pathogens. The MIC90s of biapenem (BIPM) for methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Haemophilus influenzae were 0.12, 32, 0.25, 0.06, 4 and 8 micrograms/ml, respectively. In comparison with other antibiotics, the activity of biapenem (BIPM) for P. aeruginosa was as potent as meropenem (MEPM), but for H. influenzae it was slightly less than those of other antibiotics, and for other respiratory pathogens it was as potent as those of other antibiotics. The MIC90s of biapenem (BIPM) for Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens were 0.06, 1, 1, 0.5 microgram/ml, respectively, and which were equal to or somewhat lower than those of other antibiotics. Biapenem (BIPM) showed strong activity against Gram-positive and Gram-negative pathogens, especially P. aeruginosa in general. Based on these results, biapenem (BIPM) is seemed to be highly useful antibiotic for the treatment of respiratory infections with several organism.

Bacteria↗
PubMed1998

DNA damage induces p21 protein expression by inhibiting ubiquitination in ML-1 cells.

We previously reported that deferoxamine, an iron chelating agent, induced p53 and cell accumulation in the G1 phase of ML-1 cells in the same way as the DNA damaging agent, etoposide. Etoposide treatment increased expression of the p21 gene, a cyclin kinase inhibitor, at both the mRNA and protein levels. However, deferoxamine treatment only increased the p21 mRNA level without the appearance of a detectable protein product. A substrate for cyclin kinase, pRB, was unphosphorylated by etoposide treatment, but remained unaffected by deferoxamine, indicating that p21 was functional after etoposide, but not after deferoxamine treatment. Therefore, in the present study, we investigated the involvement of the ubiquitin proteasome pathway in post-transcriptional regulation of p21. By the addition of lactacystin, a proteasome inhibitor, to deferoxamine treatment, the level of unubiquitinated p21 protein product was similar to that induced by etoposide treatment, and the ubiquitinated p21 bands became apparent. After etoposide treatment, the level of ubiquitinated p21 was diminished and a high level of unubiquitinated p21 expression was observed. We concluded that (1) efficient expression of p21 protein requires inhibition of the ubiquitin-proteasome pathway, and (2) DNA damage inhibits the ubiquitination of p21.

Acetylcysteine↗
PubMed1998

Short-term and long-term cytokine release by mouse bone marrow mast cells and the differentiated KU-812 cell line are inhibited by brefeldin A.

Mast cells and basophils produce a wide range of cytokines, including large amounts of both IL-6 and granulocyte-macrophage CSF (GM-CSF). However, the route by which cytokines are secreted is poorly understood. In the current study, we used two inhibitors of vesicular transport, brefeldin A and monensin, to examine the routes of secretion of IL-6 and GM-CSF in the differentiated KU812 human cell line and cultured mouse bone marrow mast cells (mBMMC). Studies of cytokine production over 6 to 24 h demonstrated that IL-6 and GM-CSF release from both cell types were inhibited by brefeldin A (BFA) following activation with calcium ionophore, A23187. Monensin had similar inhibitory effects to that of BFA on the initial and ongoing IL-6 release from KU812 cells. In contrast, the amount of each cytokine remaining within the cells was significantly enhanced. Similar results were obtained following IgE-mediated activation of mBMMC. BFA significantly inhibited both the constitutive secretion of IL-6 and the immediate ionophore-induced increase in IL-6 release from KU812 cells at 20 min postactivation. However, treatment with these agents did not alter the release of histamine and beta-hexaminidase from either mBMMC or KU812 cells. These studies suggest that both the initial 20-min release of IL-6 and secretion of IL-6 and GM-CSF over up to 24 h by mBMMC and differentiated KU-812 cells occur predominately through a vesicular transport-dependent mechanism, and that little, if any, IL-6 and GM-CSF is released through degranulation.

Animals↗
PubMed1998

Structure-activity relationships of the 7-substituents of 5,4'-diamino-6,8,3'-trifluoroflavone, a potent antitumor agent.

Recently, we reported that 5,4'-diamino-6,8,3'-trifluoroflavone (1b) exhibits potent antitumor activity against certain types of human cancer cell lines both in vitro and in vivo. Since the antiproliferative activity of 5,4'-diaminoflavone (1a), the lead compound of 1b, was modulated by the addition of apigenin, we hypothesized that the 7-position is important for the interaction with a putative target molecule. On the basis of this hypothesis, the structure-activity relationships of the substituents at the 7-position of 1b were explored. As a result, 7-methyl (7a), 7-hydroxymethyl (7l), 7-(acyloxy)methyl (9a,c,e,g,j), and 7-aminomethyl (12f) derivatives were found to exhibit comparable or superior antitumor activity to compound 1b against MCF-7 cells both in vitro and in vivo (po administration). In particular, compounds 9e,g,j, and 12f were sufficiently water-soluble as compared with 1b which hardly solubilizes in water. A lipophilic 7-(hexanoyloxy)methyl derivative (9c) was also found to exhibit strong antitumor activity especially in vivo. Since the modes of action and the target molecule(s) are unknown, a mechanistic study will be important in the future.

Animals↗
PubMed1998

Mucosa-adhesive water-soluble polymer film for treatment of acute radiation-induced oral mucositis.

PURPOSE: To examine the usefulness and safety of a mucosa-adhesive water-soluble polymer film (AD film) containing anesthetics and antibiotics for the treatment of acute radiation-induced oral mucositis. MATERIALS AND METHODS: To prepare AD films, 600 mg of hydroxy-propyl-cellulose was dissolved in ethyl alcohol, and mixed with a solution containing tetracaine, ofloxacine, miconazole, guaiazulene, and triacetin. The gel obtained was dried to form 30 translucent round sheets (20 mg per sheet) of 7.5 cm in diameter and 0.2 mm in thickness. The AD film showed excellent adhesive and coating properties when placed on wet oral mucosa. From 1993 to 1994, we used the AD film in 25 patients with acute radiation-induced oral mucositis, in an attempt to alleviate their pain and prevent secondary oral infection. All patients had received definitive radiotherapy for oral carcinoma. Intensity and duration of oral pain from mucositis, relief rates at rest and while eating, and presence of bacterial and/or fungal infection were compared with those of 27 patients treated with topical anesthetics (viscous lidocaine, Xylocaine and/or general systemic analgesics from 1990 to 1992 (NonAD Group). RESULTS: The intensity of oral pain was the same in the two groups. The mean duration of pain of the AD film Group (10 days) was significantly shortened compared with the NonAD Group (15 days). The rates of complete pain relief at rest and while eating of the AD film Group were statistically higher than those of the NonAD Group: 82% vs. 44%, and 68% vs. 22%, respectively. No secondary bacterial or fungal infections were observed in the AD film Group, whereas 4 cases of documented infections were found in the NonAD Group. No acute or chronic adverse effects of AD film were observed during the 3-year follow-up period. The rates for local control of oral carcinoma and overall survival, at the end of the follow-up period, were 96% and 87% for the AD film Group vs. 92% and 85% for the NonAD Group, respectively. CONCLUSION: The AD film, containing topical anesthetics and antibiotics, proved useful to alleviate pain due to acute radiation-induced oral mucositis, maintain good peroral feeding, and prevent secondary oral infections, without inducing adverse reactions.

Administration, Buccal↗
PubMed1998

Improvement of promoter activity by the introduction of multiple copies of the conserved region III sequence, involved in the efficient expression of Aspergillus oryzae amylase-encoding genes.

The role of the conserved sequence region III in the promoter regions of the amylase-encoding genes amyB, glaA and agdA of Aspergillus oryzae was examined. Introduction of multiple copies of the region III fragment into the agdA promoter resulted in a significant increase in promoter activity at the transcriptional level. This result suggests that the fragment comprising region III consists of one or more cis-acting sequence(s). Moreover, expression of the agdA gene under the control of the improved agdA promoter resulted in efficient overproduction of alpha-glucosidase, even in the presence of glucose. Thus, overexpression of genes controlled by the improved promoter incorporating region III is possible. Interestingly, expression of the amyB and glaA genes in the transformant was strongly repressed. This result suggests that the trans-acting regulatory protein(s) that interact with region III are common to these amylase genes and that the titration of regulatory protein(s) reduced the expression of the amyB and glaA genes.

Amylases↗
PubMed1998

Antitumor activity of KW-2170, a novel pyrazoloacridone derivative.

5-(3-Aminopropyl)amino-7,10-dihydroxy-2-(2-hydroxethyl)-aminoethyl -6H-pyrazolo[4,5,1-de]acridin-6-one dihydroxy-chloride (KW-2170), a novel derivative of pyrazoloacridone, was selected and evaluated for its antitumor activity and toxicity in mice. KW-2170 exhibited antitumor activity superior to adriamycin (ADM) against Sarcoma 180, breast carcinoma MM102 and fibrosarcoma Meth A inoculated s.c. in mice. Its therapeutic index (LD10/ED50) was higher than that of ADM on two murine carcinoma models, MM102 and Meth A. KW-2170 showed significant antitumor activity against 17 human tumor xenografts of a total of 24 tumors tested and the total tumor response rate by treatment with KW-2170 was significantly higher than that by ADM (70.8 versus 58.3%). In particular, human lung carcinoma was highly sensitive to KW-2170, and a marked tumor regression was observed on Lu-65 and Lu-99 human lung carcinoma xenograft models. Ovary and pancreas carcinomas were also sensitive to the drug. Additionally, its therapeutic index was also high on these human carcinoma models in comparison with that of ADM. The best antitumor efficacy of KW-2170 was observed by a weekly treatment schedule followed by a single treatment schedule and a successive administration schedule also tended to be toxic to the hosts. KW-2170 exhibited very low cross-resistance against four lines of multidrug resistant tumors expressing high levels of P-glycoprotein, and the drug showed significant antitumor activity against ADM-resistant human ovary carcinoma A2780/ADM and against nasopharynx carcinoma KB-A1 xenografts which were not sensitive to ADM. These results indicate that KW-2170 has a very potent antitumor activity and is feasible as a new antitumor drug against ADM-refractory solid tumors in clinics.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[New application of ultrasound imaging using contrast agent].

Recently, various ultrasound contrast agent have been developed all over the world. This paper reviewed recent development of some contrast agent and clinical application of new imaging using contrast agent (Enhanced color Doppler Imaging, Harmonic Imaging, Flash Echo Imaging and Loss of Correlation Imaging). These new methods are easily feasible with a clinical ultrasound diagnosis machine for evaluating further information, for example, slow or deeply located lesion's blood flow, furthermore tissue perfusion. Contrast enhanced ultrasound imaging such as Harmonic imaging is enable to evaluate tissue function.

Animals↗
PubMed1998

[Occurrences of penicillin-binding protein 2B gene in clinically isolated penicillin-resistant Streptococcus pneumoniae].

We analyzed 88 strains of Streptococcus pneumoniae (S. pneumoniae) isolated in Showa University Hospital from June 1995 to July 1996. The ratios of antibiotic resistance were 39% to penicillin G, 50% to erythromycin, and 2% to imipenem. No resistant to cefotaxime and ofloxacin was observed. Thirty-four strains (39%) were considered to be penicillin-resistant S. pneumoniae (PRSP) strains (MIC of penicillin G > or = 0.5 microgram/ml), according to the breakpoint determined by the Japanese Working Group for Penicillin-Resistant Streptococcus pneumoniae. The ratio of PRSP was higher in S. pneumoniae isolated from inpatients (25/47) when compared to that from outpatients. By PCR analysis, DNA regions of autolysin were amplified in all the 88 strains, confirming that the isolates were S. pneumoniae. Penicillin-binding protein 2B (PBP2B) class B region was positive in 32 strains, and PBP2B class A was in 2 strains. Twenty eight of 34 strains of PRSP contained the PBP2B class B gene. In the remaining six PRSP strains, neither the PBP2B class A nor B region was amplified. The PBP2B class B region was detected as a 180-kb fragment of SmaI digestion of S. pneumoniae DNA by Southern blot analysis, confirming that the detection of PBP2B class B gene by PCR is reliable. We concluded that the PBP2B class B gene is considered to be a major gene responsible for phenotypic resistance of PRSP. We performed genotyping by SmaI digestion pattern using pulsed field gel electrophoresis. No identical pattern was observed in isolates from inpatients, suggesting that apparent nosocomial infection of S. pneumoniae was negligible.

Aminoacyltransferases↗