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Biomedical subjects

H Hamada

Publications and source records attributed to H Hamada.

At least 541 records · Page 30Linked to original sources
PubMed1982

[Clinical use of amikacin sulfate in the treatment of bacterial infections and prevention of postoperative infections in the orthopedic field].

Investigation was made on the effectiveness and safety of amikacin (AMK) in the treatment of bacterial infections and prevention of postoperative infections in the orthopedic field. The details of 14 infectious patients treated with AMK were as follows; osteomyelitis in 5, purulent arthritis in 3, decubitius in 3, cystitis in 2 and purulent peritonitis in 1. For prevention of postoperative infections, AMK was administered to 9 patients. In 14 infectious patients, clinical response was excellent in 2, good in 11 and poor in 1, while in 9 postoperative patients clinical response was excellent or good in all of them. As side effects, a slight rise of the GOT and GPT levels was observed in 1 but normalized by discontinuation of the medication. In the aspects of effectiveness and safety, AMK may be considered to be a useful available antibiotic in the orthopedic field.

Adolescent↗
PubMed1981

Mutated beta-actin gene: coexpression with an unmutated allele in a chemically transformed human fibroblast cell line.

By in vitro translation, we have identified the mRNA species that codes for a novel actin polypeptide (Ax-actin) in the chemically transformed human fibroblast line HuT-14. The relatedness of the coding sequences of the Ax- and beta-actin genes is indicated by our finding that pcDd actin ITL-I DNA, a recombinant plasmid DNA that contains a DNA sequence complementary to actin mRNA of Dictyostelium discoideum, hybridizes both the Ax-actin mRNA and the beta-actin mRNA but not the gamma-actin mRNA. In contrast, pcHa-1 DNA, a recombinant plasmid constructed by cloning a DNA sequence complementary to human actin mRNA from HuT-14 cells into pBR322, hybridized to all three mRNA species. In addition, no difference was observed between Ax- and beta-actin mRNAs when their molecular size was determined either by sucrose density gradient sedimentation or by methyl mercury agarose gel electrophoresis. Southern blot transfer of radioactive pcDd actin DNA to restriction endonuclease-digested Hut-14 DNA produced only a single hybrid band (a 6-kilobase fragment); the pcHa-1 DNA probe detected one additional band (a 3-kilobase fragment). These results suggest that HuT-14 cells contain only one copy per haploid genome for Ax- or beta-actin. When considered together with recent determination of the entire amino acid sequences of Ax- and beta-actin, our findings indicate that Ax-actin is the product of a mutated beta-actin gene and are evidence for the occurrence of a mutation in a chemically transformed cell.

Actins↗
PubMed1980

3'-terminal processing of ribosomal RNA precursors in mammalian cells.

The 3'-terminal structures of ribosomal 28S RNA and its precursors from rat and mouse were analyzed by means of periodate oxidation followed by reduction with 3H-borohydride. 3'-terminal labeled nucleoside derivatives produced by RNase T2 digestion were determined by thin-layer chromatography and oligonucleotides generated by RNase T1 digestion were analyzed by DEAE-Sephadex chromatography. In the rat, the major 3'-terminal sequences of ribosomal 28S RNA, nucleolar 28S, 32S, 41S, and 45S RNAs were YGUoh, GZ2Uoh, GZ12Uoh, GZ2Uoh, and GZ7Goh, respectively, whereas in the mouse corresponding sequences were YGUoh, GZ1,2, or 3Uoh, Goh, Uoh and GZ 13Uoh, respectively. (Y: pyrimidine nucleoside, Z: any nucleoside other than guanosine) These results suggest that a "transcribed spacer" sequence is present at the 3'-terminus of the 45S pre-ribosomal RNA, which is gradually removed during the steps of processing.

Animals↗
PubMed1980

In vitro splicing of SV40 late mRNA in isolated nuclei from CV-1 cells.

An in vitro splicing system utilizing isolated nuclei of SV40 infected cells has been developed. Nuclei were isolated from CV-1 cells at a late stage of SV40 infection after a pulse-labeling with 3H-uridine. In nuclei prepared under mild isotonic conditions, 19S viral coded RNA synthesized in vivo was converted in vitro into 16S mRNA. In contrast, the nuclei prepared with RSB, a hypotonic medium, showed a very low splicing activity only. Addition of a "nuclear extract" to these nuclei restored the activity almost to the original level. These results indicate that 1) 19S RNA is indeed a precursor to 16S mRNA 2) the splicing of 19S RNA into 16S RNA takes place in the nucleus, and 3) at least a part of the enzyme system required for splicing could be extracted from the nucleus. This in vitro system may be useful for the assay of the splicing enzyme(s).

Base Sequence↗
PubMed1980

Identification of type A and type C virus particles in BF murine osteosarcoma.

Two types of virus particles, intracisternal type A and extracellular type C with budding, were detected in the same cells of BF osteosarcoma, its cultured cell lines, and their BFO tumors in CBA mice. The type C particles were approximately 100 microns in diameter. The buoyant density of the virions was 1.16g/ml in sucrose and 1.07 g/ml in Ficoll. A 72S RNA was demonstrated by gel electrophoresis, but no DNA was detected. Reverse transcriptase activity was also demonstrated in detergent-treated virions. Thus, the particles seem to be RNA virus. Cellular transformation and focus formation were observed after rat and mouse embryo cell monolayers were infected with the virus. The same kind of osteosarcoma was produced by inoculation of cloned transformed cells (BFOSV) of CBA embryo cells into CBA mice. Thus, the virus seems to be an oncornavirus.

Animals↗
PubMed1980

[A case of intracranial chordoma with a special reference to the findings in computed tomography (author's transl)].

A case of chordoma was reported with a special reference to the computed tomography. A 22-year-old female, who had been in good health, was admitted to Kagoshima University Hospital on December 8, 1978 with a chief complaint of diplopia. Physical examination was nothing particular and neurologic examination revealed the left abducent nerve palsy. The labolatory findings including blood count, serum electrolytes, hormonal study, carcinoembrynonic antigen (CEA) and alpha-fetoprotein were within normal limits. Plain skull filsm showed a retro-sellar calcification in combination with a bony erosion of the dorsum sellae and the clivus. The left vertebral arteriography and the left carotid arteriography showed a space taking lesion extended from the retro-clival to the left parasellar region. The axial CT scanning showed a round and irregular high density area consistent with calcification, at the retro-clival area, middle cranial fossa, and parasellar region in the left side, and no enhancement effect was acquired. The coronal CT appearance showed a round but discontinuous high density area like a coral reef, based on the clivus. These CT findings indicated the extension of the space taking legion, clearly. Intra-capsular removal of the tumor was performed and histologic examination confirmed the chordoma. It will be emphasized that CT scan, particularly coronal section was one of the most useful diagnostic procedure of amss of the skull base.

Adult↗
PubMed1979

In vitro synthesis of a 5S RNA precursor by isolated nuclei of rat liver and HeLa cells.

Isolated rat liver nuclei were incubated under appropriate conditions in the presence of 0.5 micrograms/ml alpha-amanitin and an RNAase inhibitor prepared from cytosol fraction, together with alpha-32P-UTP or alpha-32P-CTP and three other nucleoside triphosphates. RNA extracted by an SDS-hot phenol procedure was fractionated with sucrose density gradient centrifugation followed by acrylamide gel electrophoresis. Fingerprint analysis of the in vitro synthesized "5S" RNA, which was slightly larger than mature 5S RNA on gel electrophoresis, showed that it contained all the sequences of mature 5S RNA except for the oligonucleotide at the 3' end. Instead, it contained two additional spots which were not present in mature 5S RNA. Analysis of the extra spots revealed that they were derived from the 3' end of the in vitro synthesized "5S RNA, which were sequenced tentatively as -CUUGAUGCUUoh (extra sequence underlined). The 5' end of the product was (p)pGU--. Isolated HeLa cell nuclei synthesized similar sized "5S" RNA under the same conditions. We conclude from these results that in isolated nuclei of these mammalian cells RNA polymerase III starts transcription of 5S RNA gene at the same site as the 5' end of mature 5S RNA, proceeds toward the 3' direction and stops at a site probably 8 nucleotides downstream from the 3' end of mature 5S RNA. Experiments with a short pulse and with various "chases" have demonstrated the presence of a short-lived precursor 5S RNA which is similar in size and sequence to in vitro "5S" RNA, suggesting that 5S RNA is synthesized in vivo as a longer precursor molecular as demonstrated in this in vitro system, and is rapidly processed into mature 5S RNA.

Animals↗
PubMed1979

Bioconversion and biosynthesis of 16-membered macrolide antibiotics. XIII. Regulation of spiramycin I 3-hydroxyl acylase formation by glucose, butyrate, and cerulenin.

The effects of glucose, butyrate, and cerulenin on the formation of spiramycin I 3-hydroxyl acylase were investigated by using the cell-free extract prepared from the spiramycin-producing strain of Streptomyces ambofaciens KA-1028. Glucose induced the formation of the acylase, and this induction was remarkably repressed by butyrate. Cerulenin, on the other hand, not only cancelled the repression by butyrate but also stimulated the formation of the acylase. The unsuccessful trapping of spiramycin I as an intermediate during the bioconversion from neospiramycin I to spiramycin III in the presence of cerulenin was due to the rapid acylation of spiramycin I caused by the acylase induced by cerulenin.

Acyltransferases↗
PubMed1979

Effect of glucose and oxygen on the structure of the plasma membrane of Staphylococcus aureus.

The effects of glucose and oxygen on the formation of the plasma membrane of Staphylococcus aureus were studied. Phospholipids were consistent components of the membrane and were not affected by glucose or oxygen. Phospholipid fatty acids in cells grown in glucose containing media were rich in Ceven (C18, C20) fatty acid chains, whereas cells grown in glucose deficient media (normal broth) had anteiso Codd (C15,C17) fatty acid chains in place of Ceven chains. This may indicate increased membrane rigidity of the cells grown in glucose containing media. Cytochromes and ATPase were present in the membrane from cells grown in normal broth, but were deficient in the cells grown in glucose containing media. Polypeptide analysis of the membrane proteins showed a deficiency of the bands corresponding to these enzymes. They were not induced by the additionof oxygen to cells grown in glucose containing media. It was concluded that glucose was the dominant factor inhibiting the formation of these membrane enzymes.

Cell Membrane↗