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Biomedical subjects

N Higashi

Publications and source records attributed to N Higashi.

At least 73 records · Page 4Linked to original sources
PubMed1991

TNF-mediated cytotoxicity. Importance of intracellular cGMP level for determining TNF-sensitivity.

Previous work on the cytolytic action of activated macrophages indicated that tumor necrosis factor (TNF) showed synergistic cytolytic activity with NO, which has been shown to act as a cyclic GMP (cGMP) generator [Higuchi et al., J. Immun. 144, 1425-1431, (1990)]. In this study, we investigated the relationship between the accumulation of intracellular cGMP and the cytotoxic action of TNF. It was demonstrated that TNF-mediated cell lysis was closely related to the background level of intracellular cGMP, and that the accumulation of cGMP within TNF resistant cells induced TNF sensitivity. We reached these conclusions on the basis of the following results; (1) agents (sodium nitroprusside and isobutylmethylxantine) that cause the accumulation of cGMP intracellularly increased the TNF-sensitivity of TNF-resistant cells; (2) the addition of dibutyryl cGMP to TNF-resistant cells increased the TNF-sensitivity; and (3) treatment at 40 degrees C or agents such as interferon gamma and actinomycin D, that synergistically kill tumor cells together with TNF, potentially increased the cGMP level. Therefore, intracellular cGMP may be one of the key molecules that lead to cell death caused by TNF.

Animals↗
PubMed1991

Human monocytes in a long-term culture with interleukin-2 show high tumoricidal activity against various tumor cells.

We compared the tumoricidal activity of human monocytes cultured with interleukin-2 (IL-2) or human recombinant interferon-gamma (IFN-gamma) alone, or IFN-gamma in combination with a small amount of lipopolysaccharides (LPS). Human monocytes cultured with IL-2 for 7 days or longer, termed lymphokine-activated macrophages (LAMs), showed higher tumoricidal activity than those cultured for 1 day. In contrast, monocytes cultured with IFN-gamma alone or in combination with LPS for 7 days or longer showed lower tumoricidal activity. LAMs were identified as macrophages by nonspecific esterase staining and immunofluorescence staining with anti-CD14 antibody. LAMs were not induced in fetal calf serum-containing medium, but they were induced when colony-stimulating factor-1 was added to the medium. LAMs showed high tumoricidal activity against all human and murine tumor cell lines tested, although they showed no cytotoxic activity against human normal cells. During incubation with IL-2, tumoricidal activity of LAMs was maximal at days 8-16 and was sustained until day 28. The difference in tumoricidal mechanism between LAMs and lymphokine-activated killer (LAK) cells was also shown by using two kinds of cytotoxic assay systems. LAMs require a long incubation time to kill tumor cells, but LAK cells can kill them immediately. Furthermore, LAMs kill tumor cells with complete DNA degradation, whereas LAK cells can induce significant but not complete DNA degradation. These results indicate that LAMs and LAK cells have different tumoricidal mechanisms for killing target cells, although they were induced by incubation with the same lymphokine, IL-2.

Animals↗
PubMed1990

Cytolytic mechanisms of activated macrophages. Tumor necrosis factor and L-arginine-dependent mechanisms act synergistically as the major cytolytic mechanisms of activated macrophages.

We examined the cytolytic mechanisms of activated macrophages by using proteose peptone- or thioglycollate broth-induced mouse peritoneal macrophages or mouse macrophage hybridomas as effector cells, L.P3 cells, a clone of L929 cells, and P815 cells as target cells, and IFN-gamma and LPS as activators. It was determined that TNF is the main cytolytic molecule against L.P3 cells from the following results: 1) activated macrophages can produce TNF; 2) TNF shows cytotoxic activity against L.P3 cells; 3) the addition of anti-TNF antibody inhibited most of the cytolytic activity of activated macrophages against L.P3 cells. On the other hand, it was concluded that the main cytolytic mechanism against P815 cells is the production of NO2-/NO3- from L-arginine, from the following results: 1) activated macrophages can produce NO2-; 2) NaNO2 shows high cytotoxic activity against P815 cells; 3) the depletion of L-arginine from the medium inhibited most of the cytolytic activity of activated macrophages against P815 cells and NO2- production by activated macrophages. In this study, however, cytostatic effects of L-arginine-dependent effector mechanism were not studied. Thus, these results show that activated macrophages can express at least two cytolytic mechanisms independently, namely, the one that appears to be mediated by the L-arginine-dependent effector mechanism and the second that appears to be mediated directly by TNF. Furthermore, it was demonstrated that TNF and L-arginine-dependent NO2- production act synergistically as killing mechanisms of activated macrophages. These mechanisms can explain the cytolytic activity of activated macrophages against a variety of target cells.

Animals↗
PubMed1990

[A case of the anomalous intercostal, subcostal and lumbar arteries in man].

This report describes an anomalous case of the multiple ipsilateral common trunk formation in the parietal arteries encountered during observed in the dissection of a 71 year-old Japanese female cadaver in the anatomical laboratory of Kanazawa Medical University. This subject had thirteen parietal arteries. Among the thirteen parietal arteries two arose from both the subclavian arteries (superior intercostal artery), and eleven arose from the descending aorta (aortic parietal arteries). Five arteries (R-1-R-5) were located on the right side, and eight (L-1-L-8) on the left. Of the eleven aortic parietal arteries, nine formed the ipsilateral common trunk, and the other two were independent branches (left 11th intercostal and 2nd lumbar arteries). The branching states of these parietal arteries were as follows: on the right side, R-1 was the common trunk for the 1st and 2nd intercostal arteries (the right superior intercostal artery), R-2 (was the common trunk) for the 3rd, 4th, 5th, 6th and 7th intercostal arteries, R-3 for the 8th and 9th intercostal arteries, R-4 for the 10th and 11th intercostal arteries and R-5 for the subcostal, 1st, 2nd, 3rd and 4th lumbar arteries. On the left side, L-1 was the common trunk for the 1st and 2nd intercostal arteries (the left superior intercostal artery), L-2 for the 3rd, 4th and 5th intercostal arteries, L-3 for the 6th and 7th intercostal arteries, L-4 for the 8th, 9th and 10th intercostal arteries, L-6 for the subcostal and 1st lumbar arteries, and L-8 for the 3rd and 4th lumbar arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Effect of systemic administration of mouse recombinant interferon-gamma on the lung tumor metastases in mice.

The purpose of this study was to examine the effective anti-metastatic activity by multiple i.v. administrations of mouse recombinant interferon-gamma (IFN-gamma) against pulmonary metastases of 3LL or B16-BL6 melanoma cells after surgical excision of primary tumors. Multiple treatments with IFN-gamma reduced effectively the incidence of pulmonary tumor metastases. Repeated 4 consecutive treatment modalities with IFN-gamma showed remarkable reduction of lung tumor colonies, and also rendered alveolar macrophages (AM) cytotoxic against B16-BL6 cells. In contrast, 14 consecutive administrations of IFN-gamma at any doses (10(2) and 10(3) U/mouse) could not activate macrophages to become cytotoxic, but were effective in regressing metastases. Thus, antimetastatic activity of IFN-gamma may be due to the stimulation of host immune defense systems such as induction of tumoricidal macrophages, presumably the direct antiproliferative action to tumor cells, or both actions under the appropriate administration conditions. We found that the systemic administration of IFN-gamma under appropriate multiple treatment modalities results in the reduction of the lung metastases and can activate AM to become tumor cytotoxic at relatively low doses (10(2) U). High-dose IFN-gamma in the multiple administration schedule was also effective for the reduction of lung tumor colonies, but strongly suppressed the nonspecific immune function and could not activate tumoricidal properties of AM.

Animals↗
PubMed1988

A novel outer-membrane-associated protease in Escherichia coli.

Human gamma interferon produced by recombinant Escherichia coli was degraded by endogenous protease after cell disruption. Specific cleavages took place at the center of two pairs of basic amino acids (Lys-131-Arg-132 and Arg-142-Arg-143) in the C-terminal region, giving rise to products with molecular weights of 17,500 and 16,000. The proteolytic activity was associated with the outer membrane of E. coli. It was insensitive to the protease inhibitors diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, tosyl-L-lysine chloro-methyl ketone, EDTA, and p-chloromercuribenzoate. Benzamidine and the bivalent cations Zn2+ and Cu2+ inhibited the activity. Dynorphin A(1-13) (Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys) was a good substrate and was preferentially cleaved at the center of Arg-6-Arg-7. Neither the amino nor carboxyl sides of Arg-9 and Lys-11 were digested. These results indicate that the protease specifically cleaves the peptide bond between consecutive basic residues and therefore is different from the known membrane enzymes, proteases IV, V, and VI. We have designated this new enzyme protease VII.

Amino Acid Sequence↗
PubMed1984

Differentiation of human pulmonary alveolar epithelial cells revealed by peroxisome changes in pulmonary proteinosis.

Regenerating areas of human lungs in pulmonary fibrosis were observed electron microscopically, and peroxidatic activity of catalase in lung peroxisomes were demonstrated cytochemically. Proliferation of Type II cells was prominent there, and some of the cells extended their cytoplasms to cover the denuded basement membrane. Unusual intermediate cells between Type II and Type I cells were observed. The extension of cytoplasmic processes with new generation of pinocytotic vesicles strongly suggested a Type I cell profile. However, catalase-positive peroxisomes were found in these cells simultaneously. From these results it was concluded that Type I cells may originate from Type II cells in human lungs as they do in experimental animals.

Catalase↗
PubMed1984

Effect of glycosidases on the properties of human interferon gamma.

Heterogeneity of human gamma interferon (IFN-gamma) induced by the combined treatment with OK-432 and Staphylococcal enterotoxin B (SEB) was demonstrated by chromatofocusing. Treatment of IFN-gamma with a mixture of neuraminidase, and beta-galactosidase eliminated the charge heterogeneity. Apparent molecular weight of IFN-gamma was decreased by enzyme treatment. These results suggest that the heterogeneity of IFN-gamma induced in our system was the result of the difference in the content of sialic acids.

Glycoside Hydrolases↗
PubMed1983

Expression in Escherichia coli of chemically synthesized gene for the human immune interferon.

A 454 base pair fragment of double stranded DNA consisting of a gene for a human immune interferon (hIFN-gamma), initiation and termination signals plus appropriate restriction endonuclease sites, was totally synthesized. The synthesis involved preparation of 62 oligodeoxyribonucleotides by rapid, solid phase procedures, and enzymatic ligation of the oligonucleotides. This synthetic gene was expressed in E. coli under the control of the lac UV5 promoter. The product has antiviral activity which was acid labile and completely neutralized by antiserum to hIFN-gamma but not by antiserum to hIFN-alpha or hIFN-beta. Molecular weight of hIFN-gamma produced by E. coli was estimated to be about 32,000 and 17,000 by gel filtration and SDS-polyacrylamide gel electrophoresis respectively.

Amino Acid Sequence↗