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Biomedical subjects

T Munakata

Publications and source records attributed to T Munakata.

At least 73 records · Page 4Linked to original sources
PubMed1985

Induction of interferon-gamma production by human natural killer cells stimulated by hydrogen peroxide.

Interferon (IFN)-inducing activity of hydrogen peroxide in human peripheral mononuclear cells was investigated. Among the mononuclear cells, purified nonadherent cells produced IFN, but not B cells and monocytes. The maximal titer of IFN by purified nonadherent cells was observed after a 72-hr cultivation in the presence of 10(-2) mM H2O2 without affecting their viability. Furthermore, the purified nonadherent cells, but not the unpurified mononuclear cells, showed an augmented cytotoxicity to K562 when stimulated with hydrogen peroxide. By using Percoll discontinuous density gradient centrifugation, peripheral blood nonphagocytic and nonadherent mononuclear cells were divided into the low and high density fractions for which natural killer (NK) cells and T cells were enriched, respectively. The NK-enriched low density fractions, but not the T cell-enriched high density fractions, showed IFN production by the stimulation of hydrogen peroxide. IFN production as well as large granular lymphocytes and HNK-1+, Leu-11+ cells of the NK-enriched fractions were abrogated by treatment of the cells with monoclonal antibody against human NK cells (HNK-1+) but not against T cells (OKT3) in the presence of complement. Moreover, hydrogen peroxide-inducing IFN production seems to be regulated by monocytes. The antiserum neutralizing IFN-alpha and IFN-beta failed to neutralize substantially IFN-produced NK cells. The treatment with either pH 2 or antiserum-neutralizing human IFN-gamma resulted in marked reduction, indicating that a major part of IFN was IFN-gamma. The purified nonadherent cells showed IFN production and augmented cytotoxicity when cultured separately from activated macrophages by opsonized zymosan; furthermore, both IFN production and enhancement of cytotoxicity were abrogated by catalase. These results suggest that both exogenous and endogenous hydrogen peroxide might be responsible for a part of immunoregulation.

Adult↗
PubMed1983

Safracins, new antitumor antibiotics. III. Biological activity.

Safracins A and B have antibacterial activity against Gram-positive and Gram-negative bacteria in vitro but no therapeutic activity in mice infected with Staphylococcus aureus. Safracins A and B induce abnormal morphological changes in Echerichia coli cells. Tests with transplantable mice tumors demonstrate that safracins A and B inhibit the growth of P388 leukemia and IMC carcinoma.

Animals↗
PubMed1982

Psycho-social influence on self-care of the hemodialysis patient.

The purpose of this paper is to clarify the psycho-social factors needed for chronic hemodialysis patients to properly engage in self-care behaviors for diet and other matters. The hypotheses concerning the psycho-social factors of self-care for hematocrit, water, sodium and potassium were verified. This study has yielded several results, of which the following four are the most important. First, since patients engage in many kinds of self-care behaviors--some effectively and others not so--it is important that we distinguish them according to their effectiveness. Some patients are in fact doing things every day that are actually detrimental to their health. Second, the physical patient's conditions, 'behavioral senses' regarding his habits, and the criticisms he receives in his work place generally tend to interfere with his self-care behaviors. Yet those who are aware of its influence and who try hard to overcome it tend to be more successful than those who are less aware and do not try as hard. Moreover, the factor that distinguishes these two types of patient is their personality characteristic of perceived 'external-internal locus of control over what happens to them'. Thus it is important to perceive the 'internal locus of control'. Fourth, since the patient's feeling that life is meaningful enables him to actively pursue self-care efforts, such a feeling helps bring about favorable medical test scores. And whether the patient is able to develop a feeling that his life is meaningful is closely related to his family and work. Therefore, it can be said that the patient will need to be provided with such psychosocial support as helping him to solve whatever problem he may have in his family and job, so that he may feel that 'life is meaningful'.

Adult↗