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Biomedical subjects

H Ozeki

Publications and source records attributed to H Ozeki.

At least 73 records · Page 4Linked to original sources
PubMed1988

[Combination chemotherapy of 5-fluorouracil (5-FU), adriamycin (ADM), cis-diamminedichloroplatinum (II) (CDDP) and mitomycin C (MMC) (FAP.MMC) in advanced gastric cancer].

Twenty patients with advanced gastric cancer were treated with FAP.MMC (5-FU 350 mg/m2 i.v. on days 1-3, ADM 40 mg/m2 i.v. on day 1, CDDP 20 mg/m2 i.v. on days 1-3, MMC 6 mg/m2 i.v. on day 1), administering 5-FU, ADM and CDDP every 4 weeks and MMC every 8 weeks. Fourteen patients were evaluable for responses. Four (29%) partial responses and two minor responses were observed. The median duration of partial response was 3.8 months (range 2.5-7 months). The median overall survival time was 5 months (range 1.5-15 months). Leukopenia was relatively severe, with a median WBC nadir of 1,300/mm3. Nausea and vomiting were frequent but moderate. However, these toxicities were clinically manageable. FAP.MMC was thus considered effective for advanced gastric cancer.

Adult↗
PubMed1988

[Phase I study of SM-5887, a new anthracycline derivative].

SM-5887, a new totally synthetic anthracycline derivative, was studied in a phase I setting. Twenty-nine evaluable courses of treatment were conducted in groups at doses increasing from 10 to 130 mg/m2. At 130 mg/m2 the median lowest WBC count was 0.7 x 10(3)/mm3 (range 0.3-1.8) and the median lowest platelet count was 57 x 10(3)/mm3 (range 4-176). Nonhematological side effects were mild gastrointestinal symptoms and hair loss. The recommended dose and schedule for a phase II setting is 100 mg/m2 every 3 weeks.

Adult↗
PubMed1987

Nucleotide sequence and molecular evolution of mouse retrovirus-like IAP elements.

We determined the nucleotide (nt) sequences of cDNA and genomic clones for murine intracisternal type A particle (IAP) elements, which are retrovirus-like repetitive sequences in rodent genomes. The nucleotide sequence of the cDNA resembled that of retrovirus RNA genomes in its lack of the U5 sequence within the 3' long terminal repeat. By sequence comparison of our clones with reported rodent IAP elements, we located the probable gag, pol and env gene regions. The sequences for the pol, env and the 3' two-thirds of the gag region were conserved among the IAP elements. In the regions, synonymous substitutions occurred more frequently than non-synonymous ones, which suggested that the regions in question were functionally constrained until fairly recently. The rate of nucleotide substitutions in the regions was estimated to be 6-10 X 10(-9) nt per site per year, and significantly higher than that of the cellular genes. These rates may exemplify a characteristic of the nucleotide substitutions for an endogenous retrovirus. The sequence homology between the IAP element and IgE-binding factor gene is discussed.

Animals↗
PubMed1987

[Combination chemotherapy with cis-platinum, vinblastine and adriamycin for non-small cell lung cancer].

A combination chemotherapy consisting of cis-platinum (CDDP), vinblastine (VLB) and adriamycin (ADM) was given to fourteen patients with non-small cell lung cancer. The treatment consisted of CDDP 60 mg/m2 i.v., divided over two days (on days 1 and 2) or five days (on days 1-5), and VLB 3.5 mg/m2 and ADM 40 mg/m2 i.v. on day 1 and repeated every four weeks. Of fourteen evaluable patients, there were two with partial responses (14%), eleven with no change and one with progressive disease. The durations of the partial responses were 3 and 4 months, respectively. The median time to disease progression in the patients with partial response plus no change was 6 months. The median survival time of all treated patients was 13.5 months. Leukopenia of less than 2,000/mm3 was seen in 36% and decreased hemoglobin of more than 1 g/dl in 50%. Mild transient renal dysfunction was observed in 7%, cumulative renal dysfunction in 29%, alopecia in 100%, nausea and vomiting in 93% and peripheral neuropathy in 43%. We conclude that a combination chemotherapy with CDDP, VLB and ADM has moderate activity against non-small cell lung cancer.

Aged↗
PubMed1987

[Phase II study of chlorambucil in patients with hematological malignancies].

Eight patients with various hematological malignancies were treated with chlorambucil, an analogue of nitrogen mustard. Five patients with CLL, 2 patients with malignant lymphoma, and one each with pseudolymphoma of the lung and primary macroglobulinemia were given 4-6 mg of chlorambucil per day for 1-2 weeks at 2-4 week intervals or a daily dose of 6 mg continuously. Two cases of CLL and one each of follicular lymphoma and pseudolymphoma achieved partial remission. Side effects included myelosuppression, especially leukopenia. Chlorambucil can be used orally without severe toxicity for longer periods and the major indication for this drug seems to be CLL and favorable type of malignant lymphoma.

Administration, Oral↗
PubMed1987

[Phase II study of prednimustine in follicular lymphoma and chronic lymphocytic leukemia].

A phase II study of Prednimustine (PMN) was conducted for follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). PMN at a dose of 40-60 mg/body, p.o. every day, was administered to 17 patients with FL and 4 with CLL. The dose and schedule of PMN was modified according to hematological toxicity. Among the 17 patients with FL, there were 6 (35.3%) CRs and 7 (41.2%) PRs, with a high response rate of 76.5%. Among the 4 patients with CLL, there were 2 PRs and one case which showed clinical improvement. PMN was effective for cases of FL and CLL refractory to alkylating agents, and therefore the result suggested a lack of clinical cross-resistance to these agents. As to the side effects observed in patients with FL, mild leukopenia (median of lowest count 3,150/mm3) occurred. One case experienced anorexia, while increased appetite was observed in 4 cases. We conclude that PMN is effective for FL and CLL, and that in addition, it has an advantage in that its mild side effects allow long-term administration through outpatient clinics, so that the quality of life for patients is not impaired.

Administration, Oral↗
PubMed1986

[Phase II study of medroxyprogesterone acetate in advanced breast cancer].

A phase II study of high-dose medroxyprogesterone acetate (MPA) was performed in 18 patients with advanced breast cancer. MPA was administered at a dosage of 1,200mg orally per day. Of the 15 evaluable patients, partial response was obtained in 3, minor response in 1, no change in 5 and progressive disease in 6 patients. The response rate was 20%, which was as effective as that of tamoxifen. As the responders had been previously treated with tamoxifen, the result suggested that MPA showed no cross-resistance to the latter. Eight patients (53%) experienced weight gain which, in 4 cases (27%), necessitated discontinuation of the treatment. One patient exhibited an allergic reaction and the drug was discontinued. Palpitation in 4 patients (27%), vaginal bleeding in 2 (13%), and edema in 1 (7%) were observed, but these effects were tolerable. We therefore conclude that high-dose MPA is an effective therapy for advanced breast cancer, and that further study is warranted.

Administration, Oral↗
PubMed1984

Nucleotide sequence of Marchantia polymorpha chloroplast DNA: a region possibly encoding three tRNAs and three proteins including a homologue of E. coli ribosomal protein S14.

The nucleotide sequence of a region of Marchantia polymorpha chloroplast DNA was determined. On this DNA sequence (3.38kb), three open reading frames (ORFs) and three putative tRNA genes were detected in the following order: -ORF701-tRNASer(UGA)-ORF702-tRNAGly(GCC)-initiator tRNAMet(CAU)-ORF703-. The ORF703 is composed of 100 codons in which those for lysine (15%) and arginine (11%) are abundant, and could be accounted for as a counterpart of E. coli ribosomal protein S14 since they share 45% homology in the amino acid sequences. The ORF701 appears to code for a membrane protein, showing a periodic appearance of seven clusters of hydrophobic amino acids. Although the mechanisms remain unknown, the ORF701 causes a streptomycin-sensitive phenotype in resistant mutants of E. coli. The ORFs and tRNA genes are separated from each other by extremely AT-rich spacers containing sequences of dyad symmetry. The third letter positions of the codons in the ORFs are also rich in A and T residues.

Base Sequence↗
PubMed1984

Identification of transfer RNA suppressors in Escherichia coli. III. Ochre suppressors of lysine tRNA.

Transducing phages of lambda carrying suppressors, lysT (Su+ beta), supG and and supL, were isolated in vivo. Upon infection with each of these phages, the production of tRNALys and tRNAVal1 was markedly enhanced. Fingerprint analysis of these tRNAs revealed that they consisted of normal tRNALys, mutant tRNALys and tRNAVal1 in equimolar ratios. The mutant tRNALys carried a single-base alteration at the anticodon, from 5'-UUU-3' to 5'-UUA-3', which makes it an ochre suppressor. DNA sequence analysis of the entire transducing fragment (730 base-pairs) of lambda pSu+ beta revealed that three tRNA genes are tightly clustered within a transcription unit in the following order; i.e. promoter-(48 base-pairs)-wild-type tRNALys-(132 base-pairs)-tRNAVal1-(2 base-pairs)-Su+ beta tRNALys-. In wild-type bacteria there are two identical tRNALys genes in one operon. Although we have shown that in Su+ beta it is the distal tRNALys that has been mutated to the ochre suppressor by a single base change at the anticodon (U36 to A36), we have not determined which of the two genes bears the supG or the supL mutation. The sequences following both tRNALys genes are highly homologous: both are about 100 base-pairs long and both terminate with an 18 base-pair sequence homologous to the last 18 bases of each tRNA. The sequences of tRNALys and tRNAVal1 are also very similar. Thus, including the 3'-portions of these tRNA genes, the 18 base-pair sequence is more or less periodically repeated five times in the DNA sequence.

Bacteriophage lambda↗
PubMed1984

Identification of transfer RNA suppressors in Escherichia coli. IV. Amber suppressor Su+6 a double mutant of a new species of leucine tRNA.

An Escherichia coli DNA fragment containing an Su+6 amber suppressor gene (supP) was cloned into a lambda gt lambda Ch vector by the shotgun method, selecting a Su+6 transducing phage lambda pSu+6. Through prophage integration followed by induction occurring at the transducing region of the lambda pSu+6 in Su- E. coli, a counterpart transducing phage carrying the wild-type allele (Su degrees 6) was isolated (lambda pSu degrees 6). The fingerprint of a tRNA encoded by lambda pSu degrees 6 was identical to that of an unidentified tRNAE previously reported (Ikemura & Ozeki, 1977). The cloverleaf structure of this tRNA was determined by combining the results of tRNA analysis and DNA sequencing of the gene. Judging from the anticodon of 5'-CAA-3', Su degrees 6 tRNA was identified as a new type of leucine isoacceptor in E. coli. Unlike other suppressors analyzed, Su+6 tRNA differed by two nucleotides from Su degrees 6 tRNA; one at the anticodon (CAA to CUA) and the other at the junction of D- and anticodon-stem (A27 to G27). DNA sequence analysis revealed that a single stretch of tRNA is flanked by the putative sequences of promoter and terminator. Thus a single copy of the Su degrees 6 tRNA gene constitutes a solitary tRNA transcription unit. Southern blotting showed only one copy of Su degrees 6 tRNA gene per haploid genome of E. coli. Since this single gene can mutate to the Su+6 suppressor, the Su degrees 6 leucine tRNA may be accounted as a dispensable species among the leucine isoacceptor tRNAs. Two possible open reading frames are found immediately following the Su degrees 6 tRNA gene.

Bacteriophage lambda↗
PubMed1984

Transfer RNA mischarging mediated by a mutant Escherichia coli glutaminyl-tRNA synthetase.

We have isolated mutations in the Escherichia coli glnS gene encoding glutaminyl-tRNA synthetase [GlnS; L-glutamine:tRNAGln ligase (AMP-forming), EC 6.1.1.18] that give rise to gene products with altered specificity for tRNA and are designated "mischarging" enzymes. These were produced by nitrosoguanine mutagenesis of the glnS gene carried on a transducing phage (lambda pglnS+). We then selected for mischarging of su+3 tRNATyr with glutamine by requiring suppression of a glutamine-requiring beta-galactosidase amber mutation (lacZ1000). Three independently isolated mutants (glnS7, glnS8, and glnS9) were characterized by genetic and biochemical means. The enzymes encoded by glnS7, glnS8, and glnS9 appear to be highly selective for su+3 tRNATyr, because in vivo mischarging of other amber suppressor tRNAs was not detected. The GlnS mutants described here retain their capacity to correctly aminoacylate tRNAGln. All three independently isolated mutant genes encode proteins with isoelectric points that differ from those of the wild-type enzyme but are identical to each other. This suggests that only a single site in the enzyme structure is altered to give the observed mischarging properties. In vitro aminoacylation reactions with purified GlnS7 protein show that this enzyme can also mischarge some tRNA species lacking the amber anticodon. This is an example of mischarging phenotype conferred by a mutation in an aminoacyl-tRNA synthetase gene; the results are discussed in the context of earlier genetic studies with mutant tRNAs.

Amino Acyl-tRNA Synthetases↗