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Biomedical subjects

S Nishimura

Publications and source records attributed to S Nishimura.

At least 865 records · Page 48Linked to original sources
PubMed1982

Mutagenicity of methylglyoxal in coffee.

Major carbonyl compounds from a extract of ground roasted coffee beans were identified as 5-hydroxymethylfurfural, acetol, glyoxal, methylglyoxal and diacetyl. Among these carbonyl compounds, methylglyoxal showed considerable mutagenic activity toward Salmonella typhimurium TA100 without S9 mix (around 100,000 revertants/mg). More than 50% of the total mutagenic activity of coffee can be accounted for by the activity of methylglyoxal.

Aldehydes↗
PubMed1982

[MQF-OK therapy in advanced terminal stomach cancer--with special reference to a comparison with MFC therapy].

Sakata, et al. has already reported that the combination therapy of mitomycin-C, carboquone, 5-fluorouracil and OK-432 (MQF-OK therapy) which had established from animal experiments, was exceedingly effective for inoperable human gastric cancer. In this paper, the effectiveness of MQF-OK therapy for inoperable gastric cancer was compared with that of MFC therapy. To perform this controlled study, a "large area" co-operative study group of cancer chemotherapy, composed of 14 institutions in Aomori and a part of Akita prefectures, was organized. From April 1977 to April 1980, patients were registered and 61 cases were evaluable; 31 out of 61 were treated with MQF-OK therapy (MQF-OK group) and the others with MFC group. The background of the cases, such as sex, age etc, was not different significantly between two groups statistically. According to the response criteria of Japan Society for Cancer Therapy, 18 cases out of 31 cases of MQF-OK group and 9 of 30 cases of MFC group showed "improvement." According to Karnofsky's criteria 17 cases of MQF-OK group and 8 of MFC group showed effectiveness more than I-A, respectively. There was a statistical significance between the two groups (P less than 0.001). By Kaplan-Meier's method, the MQF-OK group survived longer than the MFC group (P = 0.05). The complications, such as leukocytopenia, thrombocytopenia or gastrointestinal complaints, were more frequently found in MQF-OK-432 group than in MFC group (P less than 0.05). But these complications decreased or resolved spontaneously 1 to 4 weeks after the administration of MQF-OK therapy. On these results, MQF-OK therapy was considered excellent method for treatment of inoperable gastric cancer and will be furthermore attempted against other cancers.

Aged↗
PubMed1982

Characterization of a rat tRNA gene cluster containing the genes for tRNAAsp, tRNAGly, and tRNAGlu, and pseudogenes.

Molecular cloning and sequence analysis of a rat DNA fragment hybridized to purified tRNAAsp revealed that the genes for tRNAAspGAU(C), tRNAGlyGGA(G), and tRNAGluGAG are in a cluster on the rat chromosome. These genes are arranged in this order and are regularly separated by DNA regions of about 450 bp. The cluster is reiterated about 10 times on the haploid DNA and is present exclusively in a 3.3 kb region cleaved by restriction endonuclease EcoRI. Five lambda clones each containing an independent repeating unit were isolated from a rat gene library. The clones revealed that the length of the repeating unit including the 3.3 kb EcoRI fragment was at least 13.5 kb. Nucleotide sequence analysis and in vitro transcription of the 3.3 kb DNA in the isolated lambda clones showed sequence variations among the repeating units and the presence of incomplete genes for tRNAGly and tRNAGlu within the clusters.

Animals↗
PubMed1982

Synthesis of mRNA of malB operons at specific stages in the cell cycle of Escherichia coli.

The mRNA synthesis of the malB operons was examined using synchronous cultures of Escherichia coli. mRNA of the malB operons were synthetized in cell cycle-specific manners different from the bulk mRNA synthesis. The synthesis occurred in two stages during a cell cycle, one in the middle of the cycle and the other at the time slightly before cell division. Identification of the species of mRNA revealed that the malK-lamB operon was preferably transcribed in the former stage of the cycle while a major fraction of mRNA of the malE-malF operon was synthesized in the later stage.

Cell Cycle↗
PubMed1982

[Thin-section CT scan of the pituitary gland (author's transl)].

Topographic anatomy of the pituitary fossa was studied by 2 mm thin-section CT scan (Somatom II). Nineteen with normal pituitary (control group) and 20 with suspected pituitary abnormality were selected. Plain and contrast CT were performed in all cases. Contrast CT was carried out immediately after the rapid infusion of 220 ml of 30% iodinated contrast medium. In all of control group but two, pituitary gland was detected as homogenous density and its density was as same as density of normal brain tissues, and was enhanced in degree of about 25 CT number. In 2 cases, small low density was visualized in the pituitary gland. Pituitary gland was differentiated from cavernous sinus was usually higher than the pituitary gland. In abnormal group, the microadenoma of the pituitary gland was diagnosed in 5 cases and 3 out of 5 cases was proved by surgery. All 3 microadenomas proved slightly dense by plain CT and enhanced higher than normal pituitary gland by contrast CT. Polytomograms showed no abnormality of the sella turcica in one of these 3 cases. Although 3 microadenomas were detected by the abnormal enhancement, we are not sure whether all of microadenoma can be detected by CT alone. Arachnoid herniation into the pituitary fossa was diagnosed in 7 of control group and 2 of abnormal group. Four out of these 9 cases were verified by using Metrizamide CT. By plain thin-section CT, the diagnosis of arachnoid herniation seems to be possible without Metrizamide CT.

Adenoma↗
PubMed1982

[Computed tomography in brain metastases (author's transl)].

CT scan of the one hundred and sixteen metastatic brain tumors in 50 patients was reviewed and compared to the previous reports. The most common primary organ was lung (43%) followed by breast (18%), colon (10%) and kidney (6%). Solitary nodule was found in 20 patients (40%). On plain CT scan, tumor nodules were demonstrated as slightly high density in 38 (33%), isodensity in 50 (43%) and slightly low density in 28 (24%). Majority of tumor nodules were present in the corticomedullary junction (82%). Brain edema seen as a peritumoral low density was extensive in comparison with the edema in the glioma of the similar size. On contrast CT scan, ring like enhancement was seen in 41 (35%). Intra-tumoral bleeding was shown in 2 metastatic nodules from choriocarcinoma and in one metastatic nodule from renal cell carcinoma. All 3 cases were proved by surgery or autopsy.

Adult↗
PubMed1982

Archaebacterial tRNA contains 1-methylinosine at residue 57 in T psi C-loop.

1-Methylinosine was isolated from unfractionated tRNAs of Sulfolobus acidocaldarius and Halobacterium volcani. The structure of 1-methylinosine was characterized by ultraviolet absorption and mass spectral analysis. 1-Methylinosine found in these archaebacterial tRNAs was located at residue 57 in T psi C-loop, indicating that the presence of 1-methylinosine is characteristic of archaebacteria.

Bacteria↗
PubMed1981

Nucleotide sequence of cytoplasmic initiator tRNA from Tetrahymena thermophila.

The total primary structure of cytoplasmic initiator tRNA from Tetrahymena thermophila mating type IV, was determined by post labeling techniques. The sequence is pa-G-C-A-G-G-G-U-m1G-G-C-G-A-A-A-D-Gm-G-A-A-U-C-G-C-G-U-Psi-G-G-G-C-U-C-A-U-t6A -A-C-Psi-C-A-A-A-A-m7G-U-m5C-A-G-A-G-G-A-Psi-C-G-m1A-A-A-C-C-U-C-U-C-U-C-U-G-C- U-A-C-C-AOH. The nucleotide residue in the position next to the 5'-end of the anticodon of this tRNA (residue No. 33) is uridine instead of cytidine, which has been found in cytoplasmic initiator tRNAs from multicellular eukaryotic organisms. The sequence of three consecutive G-C base pairs in the anticodon stem common to all other cytoplasmic initiator tRNAs is disrupted in this tRNA; namely, the cytidine at residue 40 in this region is replaced by pseudouridine in Tetrahymena initiator tRNA.

Animals↗
PubMed1981

Reduction in calcium concentration induces exocytotic secretion of catecholamines from the adrenal medulla in the absence of extracellular ions.

Cat adrenal glands were perfused with a NaCl-free medium where all NaCl had been replaced by isotonic sucrose. Exocytotic secretion of catecholamines was evoked by a simple reduction in the concentration of Ca in the medium. The response required extracellular Ca and was blocked by Ca channel blockers. The results suggest that in the absence of most ions, Ca reduction itself increases permeability of the plasma membrane to Ca, thereby evoking secretion.

Adrenal Medulla↗
PubMed1981

Nucleotide sequences of two aspartic acid tRNAs from rat liver and rat ascites hepatoma.

The nucleotide sequences of the major tRNAAsp from rat liver and a minor tRNAAsp present specifically in rat ascites hepatoma were determined by combined use of several postlabeling procedures. The sequence of rat liver tRNAAsp was determined to be pU-C-C-U-C-G-U-U-A-G-U-A-phi-A-G-U-G-G-D-G-A-G-U-A-U-C-C-C-C-G-C-U-C-manQ-U-C-A -m5C-G-C-G-G-G-A-G-A-m5C-m5C-G-G-G-G-T-phi-C-G-A-U-U-C-C-C-C-G-A-C-G-G-G-G-A-G- C-C-AOH. The nucleotide sequence of rat ascites hepatoma TRNAAsp was found to be the same as that of rat liver tRNAAsp, except that mannose-attached queuosine (manQ) present in the wobbling position of rat liver tRNAAsp was replaced by normal guanosine in rat ascites hepatoma tRNAAsp. The other modified nucleosides in the two tRNAAsp species were the same. Thus it was concluded that the new isoacceptor species of tRNAAsp that appears in the tumor tissue is due to hypomodification with respect to Q in the posttranscriptional process. The most notable feature on the sequence of the mammalian tRNAAsp is that cytidine is present in the position next to the 5'-end of the anticodon, because the only known tRNAs having cytidine in this position are cytoplasmic initiator tRNAs from multicellular eukaryotic organisms.

Animals↗
PubMed1981

Mammalian tRNA genes: nucleotide sequence of rat genes for tRNAAsp, tRNAGly and tRNAGlu.

A cloned 2.1 kb fragment of rat DNA hybridized to purified tRNAAsp has been sequenced. The result revealed that in addition to the putative gene for tRNAAspGAU(C), the fragment contained the tRNAGlyGGA(G) and tRNAGluGAG genes. The genes for tRNAAsp, tRNAGly and tRNAGlu have the same polarity, are arranged in this order and are regularly separated by DNA regions of about 450 bp. These rat genes contain neither intervening sequences nor the CCA sequence expected in the 3'-end of the mature tRNA. As observed in lower eukaryotic tRNA genes, the 5'-flanking regions of the three rat genes do not have any significant sequence homology as a regulatory element. In the 3'-flanking region, the sequences CTTTTTG and CTTTTG are present 11 bp downstream from the 3'-end of the genes for tRNAAsp and tRNAGly, respectively. The same CTTTTG sequence is repeated twice in regions 47 and 60 bp away from the tRNAGlu gene. The short T cluster common to the three genes might be the transcription termination site as in lower eukaryotic tRNA genes.

Animals↗
PubMed1981

Possible occurrence of Na+-dependent Ca2+ influx mechanism in isolated bovine chromaffin cells.

Chromaffin cells were isolated from bovine adrenals and the effects of experimental manipulations which alter the level of internal Na+ on the release of catecholamines and 45Ca uptake by these cells were investigated. In response to NA+ deprivation both parameters were increased or decreased when internal NA+ was raised or reduced, respectively. The results suggest the existence of Na+-dependent Ca2+ influx mechanism in these cells.

Animals↗