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Biomedical subjects

T Tokunaga

Publications and source records attributed to T Tokunaga.

At least 181 records · Page 10Linked to original sources
PubMed1989

Heterogeneity of the effects of monensin on two types of contractions evoked by inhibition of Na+-K+ ATPase in the guinea-pig vas deferens.

The interactions between ouabain or K+-free medium and monensin on noradrenaline (NA) release and Ca2+-evoked contractions were assessed in guinea-pig vas deferens. Ouabain (10 microM) produced large, sustained contractions and monensin (1 microM) small, transient contractions. The ouabain-evoked contraction tended to be potentiated in the presence of monensin. The marked contraction induced by ouabain plus monensin was nearly abolished by phentolamine or by treatment with 6-hydroxydopamine. Ouabain caused the release of NA from the tissue, as determined in an HPCL-ECD study. This ouabain-evoked release of NA was enhanced by the simultaneous administration of monensin. High Ca2+ (10 mM) per se, ouabain, monensin or K+-free medium did not elicit contraction of the tissue in the presence of phentolamine. However, 10 mM Ca2+ caused a large contraction 45-65 min after exposure to ouabain or K+-free medium and this contraction was suppressed by monensin. The contraction evoked by Ca2+ in the presence of ouabain was further inhibited by amiloride, an inhibitor of Na+-Ca2+ or Na+-H+ exchange transport, but not by nifedipine, a voltage-dependent Ca2+ antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1989

A fluorescence sandwich ELISA for detecting soluble and cell-associated human interleukin-2.

A fluorescence sandwich ELISA was developed for the quantitation of human interleukin-2 (IL-2) using a combination of two anti-human IL-2 antibodies, L61 and biotinylated anti-IL-2 rabbit IgG. The minimum level of IL-2 detectable by this ELISA was 0.3 pg/ml, indicating that this method is about 100 times more sensitive than the usual colorimetric human IL-2 ELISA. The ELISA specifically detected human IL-2 in cell culture supernatants and serum, and also in extracts from mitogen-stimulated peripheral blood mononuclear cells. All of the IL-2 species detected in the supernatants, sera and cell lysates were shown to have a molecular weight of 15,000, as estimated by size exclusion high performance liquid chromatography.

Animals↗
PubMed1989

Soluble IL-2 receptor in AIDS. Correlation of its serum level with the classification of HIV-induced diseases and its characterization.

By using a fluorescence sandwich ELISA, elevated IL-2R levels were detected in the sera from both HIV-infected hemophiliacs and other HIV-infected patients. The serum IL-2R levels were reflective of the classification of HIV-induced diseases by the Centers for Disease Control. Moreover, the IL-2R levels were negatively correlated most prominently with CD4 cell counts, with lymphocyte counts, and with a decrease in the CD4-CD8 ratio but not with either WBC counts or B cell counts. As striking elevations of serum IL-2R were noted in AIDS patients with group IVD infection, the serum IL-2R was purified sequentially by using size-exclusion HPLC, high-pressure chromatofocusing, and H48 affinity HPLC. The isoelectric point values of IL-2R were separated into 4.2 and 3.8, whereas the Mr was determined to be only 45 kDa by immunoprecipitation with H48 antibody followed by SDS-PAGE. However, production of cellular and supernatant IL-2R was not elevated in PBMC of patients with AIDS or in any of the 19 HIV-I- or HIV-II-infected cell line cells. In contrast, PBMC from patients with adult T cell leukemia and cell line cells that expressed human T cell lymphotropic virus -I or -II produced soluble IL-2R, constitutively. The mechanisms by which serum levels of IL-2R might be elevated in HIV-infected patients are discussed in comparison with that in adult T cell leukemia patients.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Human immunosuppressive factors produced by T cell hybridoma.

A Human OKT8-positive T cell hybridoma was established by using concanavalin A (ConA)-activated peripheral blood mononuclear cells (PBMC) fused with CEM-AGR cells. A culture supernatant of the established T cell hybridoma HI4.2D6 inhibited the mitogen induced proliferation of peripheral blood mononuclear cells (PBMC). It inhibited IL-1-, IL-2, or IL-3-dependent proliferation of each factor-dependent mouse cell lines. While the inhibitory activity of IL-1-induced proliferation was stable, that of IL-2- and IL-3-induced proliferation was abrogated within a week at 4 degrees C. Inhibition of IL-2-dependent growth was also observed using human IL-2-dependent cells, but the growth of other factor-independent human hematopoietic cell lines was not affected at all. By gel filtration, the activity inhibiting IL-2- or IL-3-dependent proliferation was found in the fractions with approximate molecular weight of 18,000 and 100,000.

Cell Line↗
PubMed1989

Utilization and excretion of a new sweetener, fructooligosaccharide (Neosugar), in rats.

In order to study the digestibility of the fructooligosaccharide "Neosugar," [U-14C]Neosugar or [U-14C]sucrose was orally administered to germfree, conventional and antibiotic-treated rats and the radioactivities of expired 14CO2, urine and feces were determined 24 h later. More than 50% of the Neosugar was expired as CO2 in conventional rats. This was the same as for sucrose, but the time course was delayed by about 2 h. In germfree rats, no 14CO2 was released for the first 8 h, and 14CO2 released after 8 h probably reflected bacterial colonization of the gut. The radioactivity of the urine was about 3-4% in all groups, but that of the feces from germfree rats was about eight times higher than the level in conventional rats. When [U-14C]Neosugar was anaerobically incubated with the cecal contents of conventional rats, more than 10% of the added Neosugar was metabolized to CO2, about 66% to volatile fatty acids and about 7% to microbes. More than 58% of 1-14C-volatile fatty acids such as acetic acid, propionic acid or butyric acid injected directly into the cecum of conventional rats was excreted as CO2 within 24 h. These results indicate that Neosugar given orally to rats is metabolized mainly to volatile fatty acids and CO2 by intestinal microorganisms, and the volatile fatty acids produced are absorbed and further converted to CO2 in the body. Thus, the data indicate that Neosugar is partially utilized as an energy source.

Acetates↗
PubMed1989

In situ infiltration of natural killer-like cells induced by intradermal injection of the nucleic acid fraction from BCG.

Intradermal injection of MY-1, a nucleic acid fraction extracted from Mycobacterium bovis strain BCG, induced in situ infiltration of mononuclear cells, most of which were asialo GM1 (GA1)-positive as determined by immunofluorescence microscopy. The infiltration occurred with as little as 1 microgram of MY-1 and lasted for a week. Double immunofluorescence microscopy revealed that the infiltrating GA1-positive cells were all positive for Ly-5, and partially positive for Thy-1.2, but negative for Mac-1, Ia, mu-chain, Lyt-1, Lyt-2, L3T4, and Fc receptor II. They contained neither peroxidase nor nonspecific esterase. The infiltrating cells thus markedly resembled natural killer (NK) cells in their cytochemical characteristics and surface markers. DNase and RNase destroyed the GA1-positive cell-inducing activity of MY-1. These results indicate that the nucleic acid components of MY-1 are responsible for this effect.

Animals↗
PubMed1989

Two types of suppressor T cells that inhibit delayed-type hypersensitivity to Mycobacterium intracellulare in mice.

Mycobacterium intracellulare Mino grows progressively in the organs of C57BL/6 mice. When C57BL/6 mice were injected with strain Mino, very weak or almost no delayed-type hypersensitivity (DTH) to the specific antigen, M. intracellulare purified protein derivative, was observed. The DTH response was enhanced by cyclophosphamide pretreatment, indicating that some suppression mechanism(s) might be involved in DTH. In cell transfer experiments it was shown that two types of suppressor T cells, afferent type (TS-Aff) and efferent type (TS-Eff), are induced in the spleens of Mino-infected mice. TS-Aff were detected from the early stage to the late stage of infection. TS-Eff were detected only in the late stage of infection. These two types of suppressor T cells were both Thy-1 positive and Lyt-2 positive; however, TS-Aff seemed to be I-J positive, and TS-Eff seemed to be I-J negative. Cross-reactivity in suppression was observed between Mino and Mycobacterium bovis BCG but not between Mino and sheep erythrocytes. DTH to Mino and BCG was not cross-reactive. The possible role of suppressor T cells in M. intracellulare infection is discussed.

Animals↗
PubMed1989

Nuclear transplantation of male primordial germ cells in the mouse.

We examined the developmental ability of enucleated eggs receiving embryonic nuclei and male primordial germ cells (PGCs) in the mouse. Reconstituted eggs developed into the blastocyst stage only when an earlier 2-cell nucleus was transplanted (36%) but very rarely if the donor nucleus was derived from a later 2-cell, 8-cell, or inner cell mass of a blastocyst (0-3%). 54-100%, 11-67%, 6-43% and 6-20% of enucleated eggs receiving male PGCs developed to 2-cell, 4-cell, 8-cell and blastocyst stage, respectively, in culture. The overall success rate when taking into account the total number of attempts at introducing germ cells was actually 0-6%. Live fetuses were not obtained after transfer of reconstituted eggs to recipients, although implantation sites were observed. The developmental ability of reconstituted eggs in relation to embryonic genome activation and genomic imprinting is discussed.

Animals↗
PubMed1989

[Muscle fiber conduction velocity and frequency parameters of surface EMG during fatigue of the human masseter muscle. 1. Muscle fiber conduction velocity].

The muscle fiber conduction velocity is used as an indication of a localized muscular fatigue or some muscular diseases. The purpose of this study was non-invasively to estimate the conduction velocity of the human masseter muscle using surface electrode arrays. Informed consent was obtained from a group of 8 healthy subjects (24-27 yr) without functional disturbances of the jaws and with natural dentitions. Each subject was asked to perform a brief isometric contraction at 10, 20, 30, 40 and 50% of the maximum EMG amplitude and an endurance of 30 and 50% MVC in the intercuspal position. The myoelectric potential was derived from an adjacent pair of electrode wires and the velocity was estimated by the electrode distance divided by the time delay between two myoelectric signals. The time delay was calculated by the cross-correlation technique. The results obtained were as follows: 1. The muscle fiber conduction velocity slightly increased with contraction force. 2. The exponential reduction in velocity was shown during fatiguing contraction of 50% MVC. 3. The muscle fiber conduction velocity decreased with the time after fatiguing contraction. 4. It was suggested that the conduction velocity of the muscle membrane discharge was an important index of muscular fatigue.

Adult↗
PubMed1989

[Muscle fiber conduction velocity and frequency parameters of surface EMG during fatigue of the human masseter muscle. 2. Frequency parameters].

During sustained isometric contraction of the jaw muscles, muscular fatigue causes a shift towards lower frequencies in the EMG frequency power spectrum. This shift is due to a reduction of myoelectric conduction velocity. The purpose of this study was to investigate the effect of surface electrode location on the estimates of frequency components, and to determine the appropriate frequency parameters of surface EMG which provided the best fit when comparing conduction velocity. Studies were performed in the masseter muscles of 8 healthy subjects. The myoelectric potentials were derived using 12 differential amplifiers from electrode arrays. The frequency parameters calculated were as follows: peak frequency, mean power frequency, cumulative power function (10, 25, 50 and 75%), median frequency ratio, low frequency ratio and measure H. As the results, following findings were obtained: 1. The high frequency content occurred at the region of end-plate zone and tendonous insertion of the muscle. 2. EMG spectra obtained during fatigue were shifted to lower frequencies for all regions except adjacent end-plate zone. 3. The relationships between conduction velocity and frequency parameters during fatiguing contractions were almost linear except peak frequency. 4. It was concluded that the location between distal end-plate and the tendon was "stable" zone for studying muscular fatigue.

Electromyography↗
PubMed1989

Hatomamicin (YL-0358M-A), a new alkaloid antibiotic: fermentation, isolation, structure, and biological properties.

Hatomamicin, a new alkaloid antibiotic, was isolated from the culture filtrate of a strain of Saccharopolyspora. The antibiotic was extracted with EtOAc and purified by silica gel column chromatography. The free alkaloid was obtained as pale yellowish prisms from CH3CN solution. It exhibits antimicrobial activity against Gram-positive organisms. The apparent molecular formula of hatomamicin was determined to be C22H31NO5. The structure has been established by a combination of spectroscopic and X-ray crystallographic studies.

Alkaloids↗
PubMed1989

[Activation of macrophages with Hochu-ekkito].

We attempted to analyse the mode of action of Hochu-ekkito on host defense mechanism, especially the effect of the drug on macrophage activation. Peptone-induced murine peritoneal exudate macrophages were incubated with/without Hochu-ekkito and interferon-gamma (IFN-gamma) for 16 hours at 37 degrees C, and then the supernatants harvested were assayed for the activities of TNF, IL-1 and prostaglandin E2. Cytotoxic activity of the macrophages against 51Cr-labeled EL-4 tumor cells was also assayed. It was found that Hochu-ekkito rendered macrophages cytotoxic against EL-4 cells. Hochu-ekkito also augmented the production of TNF, IL-1 or Prostaglandin E2 from macrophages. Synergistic effect of IFN-gamma for augmenting production of TNF or cytotoxic activity was noted. These results suggested that Hochu-ekkito activated macrophages directly in vitro.

Animals↗
PubMed1989

[The immunology of tuberculosis].

An introductory overview on the present state and future prospect of the immunology of tuberculosis is presented with the following six chapters. 1. Contribution of tuberculosis immunologists to the modern immunology. When one reminds Koch's phenomenon, Freund's adjuvant, and the findings or new ideas of, for instance, cell-mediated transfer of tuberculin allergy, test of MIF which was first described as "lymphokines", effector macrophages activated with immune lymphocytes against mycobacterial infection, MHC-restriction for presenting tuberculin-antigen from macrophages to T cells, everyone may agree with saying that the tuberculosis immunology contributed greatly to the opening and development of modern immunology. 2. Central dogma of tuberculosis immunology. Tuberculosis immunology possesses a central dogma : infection of tubercle bacilli----phagocytosis----antigen presentation----expansion of specific T cell clone----production of lymphokines----macrophage activation----killing of the bacilli. Recent knowledges from modern immunology have clarified many things in or around this immunological process. However, there remain many important questions. In the following chapters and subtitles, what have been clarified and what are still unsolved will be described. 3. Induction of tuberculosis immunity. (1) Mechanisms of phagocytosis with macrophages, and natural resistance. (2) Antigen presentation and sensitized T cells. 4. Expression of tuberculosis immunity. (1) Lymphokines. (2) Activation of macrophages. (3) Immune suppression. 5. Special characters of tubercle bacilli in relation to the host response. Biochemistry of cellular components of tubercle bacilli and their biological activities have been reported by many investigators already in this journal. Therefore, the following items only are discussed here. (1) Mycobacterial proteins produced by gene-technology. (2) Adjuvant active derivatives of MDP. (3) DNA from BCG and its biological activities. (4) Difference of immunity induced by viable and dead bacilli. About (4), possible mechanisms to explain the difference are discussed, with emphasis of both MPB70 protein as an antigenic metabolite released from viable bacilli and the heat-shock mycobacterial proteins. 6. Unsolved problems in tuberculosis immunology. (1) Mechanisms of endogenous reactivation. (2) Development of new vaccine. (3) Others. In addition to the practical problems on tuberculin diagnosis and BCG vaccination, problems to be solved in and around the central dogma are discussed. Some examples of these problems are illustrated in Fig.7 in English.

Animals↗
PubMed1989

Mechanism of action of 15-deoxyspergualin. I. Suppressive effect on the induction of alloreactive secondary cytotoxic T lymphocytes in vivo and in vitro.

The effects of 15-deoxyspergualin (DSG) and its derivative deoxymethylspergualin (MeDSG), which is more stable than DSG in solution, on the induction of alloreactive secondary cytotoxic T lymphocytes (CTL) in mice in vivo and in vitro were determined. Secondary CTL were generated in vivo or in vitro by injecting mice with mitomycin C (MMC)-treated allogenic tumour cells twice with a 1-week interval or by culturing spleen cells of alloantigen-primed mice with MMC-treated allogenic mouse spleen cells, respectively. DSG preferentially suppressed the generation of secondary CTL at the differentiation but not at the effector phase. DSG also suppressed the responsiveness of spleen cells to secondary antigen in a non-specific manner. MeDSG suppressed the in vitro induction of secondary CTL in a dose-dependent manner; however, it did not suppress the activity of CTL already induced. The inhibitory effect of MeDSG on CTL induction was totally abolished by exogenous recombinant murine interferon-gamma (IFN-gamma) and partly by interleukin-2 (IL-2), suggesting that suppressive mechanisms of MeDSG (DSG) may be mainly mediated by the inability of lymphocytes to produce IFN-gamma or by impairment of an unknown cascade(s) reconstituted by IFN-gamma.

Animals↗
PubMed1989

[Thoracic and lumbo-sacral spinal lipoma in an infant].

We reported a case of thoracic and lumbosacral spinal lipoma in an 8 month-old boy. He was born in asphyxia. Six months after birth, spastic paraparesis developed gradually at both lower extremities and secondary funnel chest due to shallow thoracic movement and scoliosis in the thoracic region was observed. MRI was then performed where tumor mass demonstrated by the high signals in both T1 and T2 in ages was confirmed in the thoracic and lumbo-sacral regions. Surgery was performed only for the thoracic lesion which was considered primary. The tumor in the Th3-4 level had developed subdurally, while the tumor in the Th5-10 extradurally. Only partial removal could be done for the subdural tumor because its boundary with the spinal cord was not clearly identified. Postoperative histological study revealed it as lipoma. During the following 6 months only slight recovery from paraparesis was observed. Surgical intervention against the mass in the lumbosacral region was not performed for the conus medullaris was found located in its normal position and no concomitant symptoms could be observed. In summary, it is considered that spinal lipoma is rare (1% of total spinal tumor) and commonly associated with other types of congenital anomalies (in 31% of spinal lipoma). Particularly in infants, spinal lipoma in the thoracic region as experienced in our case is extremely rare and any medical treatment started after clinical symptoms once developed seems ineffective.

Humans↗
PubMed1988

Effects of granulocyte-macrophage colony-stimulating factor and colony-stimulating factor-1 on the proliferation and differentiation of murine alveolar macrophages.

Murine alveolar macrophages (AM) were shown to have proliferative ability and to form colonies in vitro. The factors in lung-conditioned medium (CM) and L929-CM which stimulate the proliferation of AM were considered to be granulocyte-macrophage colony-stimulating factor (GM-CSF) and CSF-1, respectively, because recombinant murine (rm)GM-CSF and recombinant human (rh)CSF-1 could replace the activities of lung-CM and L929-CM, respectively. The phenotype of the cells in the colonies formed by AM incubated with rmGM-CSF or lung-CM was AM-like; more than 90% of the cells were stained by anti-asialo GM1 but not by FITC-LPS, and had AM-like morphology. Expression of Mac-1 Ag determined by M1/70HL in these cells as well as original AM was low. However, the phenotype of the cells in the colonies formed by AM incubated with rhCSF-1 or L929-CM was peritoneal macrophage (PM)-like; more than 90% of the cells were stained by FITC-LPS and M1/70HL, but not by anti-asialo GM1, and showed PM-like morphology. The cells in the colonies formed by AM incubated with rmGMCSF changed their phenotype after treatment with rhCSF-1; the percentage of cells stained by anti-asialo GM1 decreased, and that of cells stained by FITC-LPS increased. The cells in the colonies formed by AM incubated with rhCSF-1 never changed their phenotype after incubation with rmGM-CSF. In contrast to AM, more than 90% of the cells in all colonies formed by PM incubated with either rmGM-CSF, rhCSF-1, lung-CM, or L929-CM were stained by FITC-LPS but not by anti-asialo GM1. These results show that although AM and PM can proliferate, AM, in contrast to PM, are bipotential cells that can differentiate into two types of macrophages responding to distinct types of CSF, and that one of the molecular mechanisms controlling macrophage heterogeneity may be based on the type of CSF produced at distinct tissues.

Animals↗
PubMed1988

Fluorescence sandwich enzyme-linked immunosorbent assay for detecting human interleukin-2 receptors.

A very sensitive fluorescence sandwich enzyme-linked immunosorbent assay (FS-ELISA) for the detection of soluble and cell-associated human interleukin-2 receptors (IL-2R) has been developed. For use in this assay system, two anti-human IL-2R monoclonal antibodies, H 48 and biotinylated HA 26, were selected from six monoclonal antibodies directed against different epitopes on the IL-2R molecule. The FS-ELISA specifically detected human IL-2R in both the culture supernatants and cell lysates of human IL-2R-bearing cells and the assay displayed a 10(3)-fold increase in sensitivity over the usual colorimetric IL-2R ELISA. The IL-2R molecules in supernatants and lysates of the PHA-stimulated mononuclear cells were of 50,000 and 60,000 molecular weight, respectively, as estimated by size exclusion high performance liquid chromatography.

Antibodies, Monoclonal↗