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Biomedical subjects

H Furuta

Publications and source records attributed to H Furuta.

At least 163 records · Page 9Linked to original sources
PubMed1988

Analysis of superhelical structures of nucleic acid-lipid conjugates by image processing.

Nucleoside-phospholipid conjugates containing a nucleotidyl residue and two long alkyl chains have been synthesized and their self-organization and morphology have been investigated. In particular, 5'-phosphatidylcytidine spontaneously assembled to form linear and circular strands. Image processing analysis of the electron micrograph of the strands confirmed that they are indeed double helix reminiscent of the double-helical structure of nucleic acids. The linear and circular strands from 5'-phosphatidylcytidine had grooves of approximately 100 A in diameter and right-handed helical pitch of approximately 240 A.

Cytidine↗
PubMed1987

Differences of superoxide production in blood leukocytes stimulated with thymol between human and non-human primates.

Thymol induced superoxide production (O2-) by blood leukocytes was examined in various primates including man. Leukocytes of chimpanzee and hamadryas baboon cells showed only 35% of the maximal O2- production rate obtained in human cells, and those of the Japanese monkey and orang-utan failed to respond. In contrast, when cells were stimulated with 12-O-tetradecanoyl phorbol acetate, no significant difference in the O2- production rate was observed between human and monkey cells except for chimpanzee. These results showed that human leukocytes are the most sensitive to thymol among the primates tested. The responsiveness of non-human primate leukocytes could be classified into two types, African-type(chimpanzee and baboon) and Asian-type(orang-utan and macaque).

Animals↗
PubMed1987

Activation of the plasma kallikrein-kinin system by Vibrio vulnificus protease.

Vibrio vulnificus protease enhanced hypodermic vascular permeability when injected into the dorsal skin of a guinea pig. Enhancement of permeability was observed within 2 min, and the permeability-enhancing reaction terminated at about 10 min postinjection. The permeability-enhancing reaction was greatly augmented by simultaneous injection of a kininase II inhibitor, whereas the reaction was inhibited by soybean trypsin inhibitor, a well-known inhibitor of plasma kallikrein. Furthermore, in vitro activation of plasma prekallikrein to kallikrein by V. vulnificus protease was observed. These results indicate that V. vulnificus protease enhances vascular permeability through activation of the plasma kallikrein-kinin system which generates bradykinin, factor in edema formation.

Animals↗
PubMed1987

[Renal cell carcinoma incidentally found by computed tomography: report of 4 cases].

A clinical study was made on 26 patients with renal cell carcinoma, who visited our department between October, 1979 and April, 1984. There were 21 men and 5 women. As the major initial symptoms, hematuria and flank pain were observed in 14 cases (53.8%), followed by symptoms of metastatic tumors in 7 cases (26.9%). Four cases of malignant renal masses which showed no abnormality on the excretory urogram were diagnosed by chance at the time of examination of the abdominal computed tomography (CT). CT was especially useful in diagnosing the renal cell carcinomas.

Adult↗
PubMed1985

Isolation and characterization of histamine-releasing peptides from human parotid saliva.

Peptides responsible for releasing histamine were purified from human parotid saliva. The amino acid composition of the peptides showed a high proportion of histidine, lysine and arginine. Molecular weights of these peptides were between 3000 and 5000 as determined by SDS-acrylamide gel electrophoresis. These peptides induced histamine release from rat-isolated mast cells accompanied with degranulation in a dose-dependent manner over the concentration range 5-50 micrograms/ml.

Amino Acids↗
PubMed1985

Histamine-release induced by 7S nerve-growth factor of mouse submandibular salivary glands.

The 7S nerve-growth factor (7S NGF) purified from mouse submandibular glands induced histamine release from rat-isolated mast cells in the presence of lysophosphatidyl-serine. When 7S NGF was injected intradermally into the rat skin, the vascular permeability increased. This response was abolished by the antihistamine, diphenhydramine. These results show that 7S NGF acts as a potent histamine releaser.

Animals↗
PubMed1985

Eugenol-mediated superoxide generation and cytotoxicity in guinea pig neutrophils.

Eugenol is the medicament used routinely as an anodyne and antiseptic in dentistry and a food flavour and fragrance agent. The drug stimulates the superoxide (O2-.) release of guinea pig neutrophils without a lag time. The production rate increases with the drug concentration and reaches a plateau at 5 mM. However, the induction accompanies the cytotoxicity. The stimulation system of O2-. production is sensitive to mild heating (45 degrees C, 15 min). The system proceeds without artifacts which may be mediated by a radical chain reaction with H2O2 and hydroxy radical, since neither catalase, mannitol nor azide changes the rate. Ca2+ and Ni2+ in the medium enhance the activity, but Mg2+ and Zn2+ have no effect. EDTA inhibits completely, suggesting that intracellular metal ions are involved in this system. Phenolic compounds used as dental medicaments other than eugenol act as potent stimulators of the O2-. production, with the following order of potency: thymol greater than eugenol greater than o-cresol. Resorcinol, guaiacol and hexachlorophene show little activity. This order of potency agrees with the order of hydrophobicity of these chemicals and that of the cytotoxicity to neutrophils. The data suggest that phenolic antiseptic drugs bind to the cell surface hydrophobically, trigger the oxygen burst and make the plasma membrane fragile at a high dose of drugs.

Animals↗
PubMed1984

Histamine release induced by dynorphin-(1-13) from rat mast cells.

Dynorphin is a potent opioid peptide. A synthetic dynorphin-(1-13) (Dyn) induced histamine release accompanied by degranulation from isolated rat mast cells in a dose-dependent manner over the concentration range 10(-7)-10(-5) M. Dynorphin-(1-13)-induced histamine release completed within 10 sec at 37 degrees C, and the release was not accompanied by the leakage of lactate dehydrogenase. Calcium (10(-5)-10(-3) M) enhanced the release, although higher concentration than 10(-3) M suppressed the release. The pH for the maximum release by Dyn was about 7.3. Disodium cromoglycate (5 X 10(-6)-10(-4) M) inhibited the histamine release by Dyn, but naloxone and leucine-enkephalin did not. These results indicate that Dyn-induced histamine release was not mediated by opioid receptors of the mast cells. Its mode of action appeared to that of anaphylactic histamine release.

Animals↗
PubMed1983

Dimeric hemoglobin of the bivalve mollusc Anadara broughtonii: complete amino acid sequence of the globin chain.

The complete amino acid sequence of a dimeric hemoglobin (HbI) from the marine bivalve mollusc Anadara broughtonii was determined by sequencing of the intact chain and peptide fragments produced by cleavage at two asparaginylglycine bonds and at methionyl, arginyl, and tryptophanyl residues. The clam hemoglobin consists of two identical polypeptide chains. The globin chain has 146 amino acid residues with a proline at the NH2 terminus and a leucine at the COOH terminus. The calculated molecular mass of the native hemoglobin was 32945 daltons. The clam hemoglobin contains only two histidine residues, which correspond to the distal and proximal heme-linked positions. Compared with human beta chain, an additional segment of seven residues is present in the NH2-terminal region and also five less residues in the COOH-terminal region. Although such an amino-terminal elongation has been known to be characteristic of hemoglobins from the most primitive living vertebrates Cyclostomata, a very similar structure was found to occur in the hemoglobin from the primitive invertebrate arcid clam.

Amino Acid Sequence↗
PubMed1983

The distribution of keratin type intermediate-sized filaments in so-called mixed tumour of the skin.

Epithelial cells can be distinguished from various non-epithelial cells by the presence of keratin-type intermediate-sized filaments, which can be detected by immunofluorescence microscopy, using antibodies to alpha-keratin. In the present study, two types of antibodies were obtained. One of them was specific for alpha-keratin (mol. wt. 49,000 to 69,000 daltons) in whole epidermis, and the other for alpha-keratin (mol. wt. 62,000 and 69,000 daltons) in prickle and granular cells but not in basal cells. Four cases of so-called mixed tumour of the skin were studied by immunofluorescence microscopy using these antibodies. Tumour cells nests of cuboidal and polygonal cells, tubular structures and keratinous cysts reacted with these antibodies, as did individually-dispersed tumour cells within the myxoid and chondroid matrix. These results indicate that all the tumour cells of the so-called mixed tumour of the skin are of epithelial origin. Differences in staining intensity between these tumor cells and their specificity for these two antibodies are discussed with reference to keratin differentiation in tumour cells.

Adult↗
PubMed1981

Ligand-dependent polymerization of tetrameric hemoglobin from the blood clam Anadara broughtonii.

Hemoglobin (Hb II) of the blood clam Anadara broughtonii has a alpha 2 beta 2 sub-unit structure in athe oxy form with a sedimentation constant of 4.8 S. When deoxygenated, Hb II polymerizes with a major component, S20,w = 11.5 (above 150 microM in heme). Deoxy polymerization was not observed in a highly diluted protein below 20 microM (in heme). Gel filtration of Hb II in the deoxygenated state indicated that the major component has an apparent molecular weight of 195 000, which corresponds to a dodecamer. However, the sedimentation pattern and the elution profile of gel filtration showed the polymerization to be somewhat asymmetric. These results suggest that deoxy Hb II may polymerize with different polymerization states. We examined oxygen equilibria of Hb II in a range of 3--180 microM (in heme). Influences of the polymerization on its oxygen affinity and cooperativity were found to be very small. We have also found that the deoxy polymerization was completely prevented when all the sulfhydryl groups of the hemoglobin molecule were modified with p-chloromercuribenzoate.

Animals↗