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Biomedical subjects

N Takai

Publications and source records attributed to N Takai.

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

Studies of the development of optical fiber sensors for biochemical analysis.

An optical fiber sensor utilizing Thymol blue and an ion-exchange resin complex in a cellulose acetate membrane was developed. By monitoring several different chromophores of Thymol blue, the sensor could measure the pH of the solution from 1.0 to 12.0 with good reproducibility. An optical fiber glucose sensor utilizing a cellulose acetate membrane containing glucose oxidase, 2,7-diaminofluorene dihydrochloride, and sodium N-(3-sulfopropyl)-3,3',5,5'-tetramethylbenzidine was developed. Reflectance changes at 580 nm were large enough to trace changes in glucose concentration in physiological saline solution.

Biosensing Techniques↗
PubMed1991

The role of substance P in parasympathetic nerve-induced secretion in the rat submandibular gland.

Fluid secretion from rat submandibular saliva evoked by electrical stimulation of the chorda tympani (parasympathetic secretory stimulation) was greatly reduced in the presence of atropine. However, some secretion was always evident at frequencies of 5 Hz and higher. The substance P-antagonist ([D-Arg1, D-Pro2, D-Trp7,9, Leu11]-substance P) also reduced the chorda-evoked saliva. Salivary secretion induced by the electrical stimulation of the superior cervical ganglion (sympathetic secretory nerve) was not affected by either atropine or substance P-antagonist. Continuous chordal stimulation reduced the glandular content of substance P to approximately 50% after 60 min, but similar stimulation of the superior cervical ganglion failed to produce such a reduction. Electron histochemical observation showed that the chordal stimulation caused depletion of substance P from the appropriate nerve fibers within the gland. The reduced secretory capability after continuous stimulation of the chorda at high frequency (20 Hz) was reversed by infusion of a subthreshold dose of exogenous substance P. Histological examination of granular duct cells revealed no degranulation in either chorda-stimulated or substance P-infused rats. The summation of findings suggests that endogenous substance P plays a complementary role in the regulation of parasympathetic nerve-induced fluid secretion in the acinus but is minimally involved in degranulation from granular duct cells.

Animals↗
PubMed1990

Simultaneous determination of ginsenosides and saikosaponins by high-performance liquid chromatography.

Octadecyl porous glass was used as the packing for reversed-phase high-performance liquid chromatography. A mixture of ginsenosides and saikosaponins (saponins of ginseng and bupleurum root, respectively) were analysed with detection at 203 nm. A well resolved chromatogram of ginsenoside Rb1, Rc, Rb2 and Rd and saikosaponin a, b2 and c was obtained with acetonitrile-water (25.5:74.5) as the mobile phase. The whole separation was achieved in 20 min with a flow-rate of 1.5 ml/min. Calibration graphs for ginsenoside Rb1, Rc, Rb2 and Rd and saikosaponin a and c were linear up to 5 micrograms. Rapid and accurate simultaneous determinations of the saponins are possible by the described method.

Chromatography, High Pressure Liquid↗
PubMed1990

Preparative high-performance liquid chromatography on chemically modified porous glass. Isolation of saponins from ginseng.

Preparative high-performance liquid chromatography on octadecylsilyl porous glass (pore size, 550 A) with acetonitrile-water as the mobile phase was applied for the isolation of saponins from Panax ginseng. In a single run, several milligrams of pure ginsenosides were obtained from 10 g of roots of Panax ginseng. The method was simple, rapid and convenient and should be applicable to isolation of other saponins of crude drugs.

Chemical Phenomena↗
PubMed1990

Inhibitory effect of validamine, valienamine and valiolamine on activities of carbohydrases in rat small intestinal brush border membranes.

Three pseudo-aminosugars, validamine, valienamine and valiolamine, produced by Streptomyces hygroscopicus subsp. limoneus showed potent inhibitory action on rat small intestinal carbohydrase activities such as sucrase, maltase, glucoamylase, isomaltase and trehalase activities, but negligible action on lactase activity and pancreatic alpha-amylase activity. Where inhibition was seen, kinetic analysis showed fully competitive inhibition of the carbohydrase activities by all three inhibitors. Valiolamine has more potent carbohydrase inhibitory activity than validamine or valienamine, and the apparent Ki values of valiolamine for sucrase, maltase, glucoamylase, isomaltase and trehalase activities were 3.2 x 10(-7), 2.9 x 10(-6), 1.2 x 10(-6), 9.1 x 10(-7) and 4.9 x 10(-5) M, respectively, which are 10(-5) to 10(-3) times smaller than the apparent Km values.

Animals↗
PubMed1990

Autonomic regulation of tight junctional permeability in the rat submandibular gland.

The permeability of tight junctions to tracers having different molecular weights was investigated in the submandibular gland of rats stimulated parasympathetically, sympathetically, or both. Lactoperoxidase (82,000 daltons), horseradish peroxidase (40,000 daltons), and microperoxidase (1,630 daltons) were used as the tracers. The tracers were administered by close arterial infusion via the glandular artery, and their secretion into the saliva was quantified biochemically, and their secretory routes within the gland were determined histochemically at the electron microscopic level. Microperoxidase and horseradish peroxidase passed into the saliva by electrical stimulation of either the chorda or superior cervical ganglion, and the combined stimulation of both caused a larger output of both tracers. No output of lactoperoxidase into the saliva occurred with any type of nerve stimulation. Electron microscopic histochemical observations showed that molecules of molecular weight equal to or lower than that of horseradish peroxidase entered the lumen through the tight junctions between adjacent acinar cells following combined stimulations of chorda and superior cervical ganglion. These findings indicate that electrical stimulation of parasympathetic and sympathetic nerves causes an increase in tight junctional permeability of acinar cells to microperoxidase and horseradish peroxidase. Although the combined stimulation of parasympathetic and sympathetic nerves resulted in increased junctional permeability to these tracers, the junctions remained impermeable to larger molecules, i.e., lactoperoxidase.

Animals↗
PubMed1989

Effects of cytokines on cultured microvascular endothelial cells derived from gerbil brain.

Microvascular endothelial cells were isolated from gerbil brain and cultured. These cells retained an endothelial-specific marker, FVIII-related antigen. Alkaline phosphatase activity was also present in early passage. Two weeks after plating, these cells were attached to the culture dishes and had become like cobblestones in appearance. Then, the addition of tumor necrosis factor at a concentration of 1000 U/ml or more suppressed the DNA synthesis activity of endothelial cells by about 70% and induced morphological changes in the cells, which developed a spindle-like form and showed overlapping of cells, indicating loss of contact inhibition. The administration of interferon-tau induced no change. When a similar experiment was performed using culture supernatants of human glioma cells that had been cultured for a few days, DNA synthesis activity was suppressed by approximately 50% or more in 6 of 12 samples. The suppression of activity, however, was abolished by the addition of anti-tumor necrosis factor antibody in these 6 cases, suggesting the presence of activity resembling that of the tumor necrosis factor in the culture supernatants.

Animals↗
PubMed1989

Analysis of mixed lymphocyte-tumor culture in patients with malignant brain tumor.

To ascertain whether tumor-specific immune response occurs in patients with malignant brain tumors, lymphocyte blastogenetic responses to tumor cells were examined in 18 patients prior to operation and other treatment. Among 12 patients with malignant glioma, the peripheral blood lymphocytes (PBL's) showed a positive blastogenetic response to their own glioma cells in seven (58.3%), whereas the tumor-infiltrating lymphocytes (TIL's) showed a positive response in only three (25%). In four (66.7%) of six patients with metastatic brain tumors, however, both the PBL's and TIL's showed a positive blastogenetic response to their own tumor cells. In these four patients, this lymphocyte blastogenetic response to tumor cells were at a much lower level compared with phytohemagglutinin P or allogeneic lymphocyte stimulation. Furthermore, these responses were increased when the cells were cultured with interferon-gamma (500 U). Other lymphokines had no effect on the response. This method appears to be useful in identifying the tumor-specific immune response in patients with malignant brain tumor.

Adolescent↗
PubMed1989

Permeability increase in rat submandibular gland by glandular substance P.

When the chorda tympani was stimulated at 20 Hz, infused horseradish peroxidase (HRP) entered the saliva through the tight junctions in the rat submandibular gland. This response was not inhibited by atropine but was reduced by a substance P(SP)-antagonist. The increase in junctional permeability for HRP never occurred in the gland that was stimulated at 5 Hz or in the SP-depleted gland. Our data suggest that the effect of parasympathetic stimulation on the increase in junctional permeability for macromolecules was due to the release of SP in the gland.

Animals↗
PubMed1988

Local administration of autologous lymphokine-activated killer cells and recombinant interleukin 2 to patients with malignant brain tumors.

Lymphokine-activated killer cells (LAK cells) were induced from lymphocytes from patients with malignant glioma by using interleukin 2 (IL-2), and their killing activity was examined. Their LAK activity against Daudi cells was 66.2 +/- 13.1% and 48.7 +/- 12.7% against self glioma cells, 54.4 +/- 10.1% against K562 cells, 43.1 +/- 7.9% against Raji cells, and 33.5 +/- 16.2% against allogeneic glioma cells. The phenotype of these LAK cells was Leu 1 (++), 2a (+/-), 3a (++), 7 (+), and 11 (++). The phenotype of precursor LAK cells, on the other hand, was Leu 1 (-), 2a (-), 3a (+), 7 (-), and 11 (++). Other activated killer cells, including LAK cells, phytohemagglutinin-activated killer cells, autoactivated killer cells, and their precursor LAK cells, were studied serologically in order to identify their phenotypic characteristics. From these data, the LAK cell populations were considered to be polyclonal. Using these LAK cells plus IL-2, local adoptive immunotherapy was undertaken in 23 patients with recurrent malignant glioma. We injected, that is, autologous LAK cells plus IL-2 directly into the cavities of the brain tumors; 1.2 to 324 x 10(8) LAK cells per ml and 0.8 to 5.4 x 10(3) units of IL-2 were directly injected into the brain tumor by using an Ommaya reservoir. Definite tumor regression, improvement of some clinical symptoms, and continuous remission over 6 mo or more were observed in six, nine, and three patients, respectively. There were no marked side effects, except for slight fever and chill, in eight and three patients, respectively. These results suggested the possibility of induction of a sufficient number of LAK cells from the lymphocytes of the patients with recurrent malignant glioma, indicating that local adoptive immunotherapy by direct injections of LAK cells and IL-2 into the brain tumor will prove to be an effective means of immunotherapy. Additional follow-up of the patients will be required before its therapeutic value can be established.

Adolescent↗
PubMed1988

In vivo and in vitro effect of adoptive immunotherapy of experimental murine brain tumors using lymphokine-activated killer cells.

Adoptive immunotherapy for the experimental murine brain tumor was investigated by using lymphokine-activated killer (LAK) cells both in vitro and in vivo. Supernatants of 48-h culture medium of spleen cells from Wistar rats in the presence of concanavalin A were used as interleukin 2 (IL-2). LAK cells were generated by cocultivation of spleen cells from Fischer rats with IL-2 with the peak reactivity on Day 2 or 3 of culture. Lytic activity was observed against not only syngenic tumor cells but also allogenic and xenogenic tumor cells, while no lytic activity was observed against normal brain cells. The cell depletion test, dye exclusion test, and immunofluorescence method using monoclonal antibodies revealed that LAK cells partially belonged to the population of the activated T-cell group, but the precursor cells did not react with any monoclonal antibodies used. On the basis of these results in vivo study was performed. LAK cells and immune spleen cells were adoptively transferred to the rats i.v. or intratumorally (i.t.) on the seventh day after the inoculation of T9, a gliosarcoma induced by methylcholanthrene from Fischer rats, into the right basal ganglia. Then the survival rate and necrotic foci were compared between the groups treated with those cells and the control. The survival rate of the groups treated with LAK cells was significantly higher than that of the control (administered i.v.; P less than 0.01, administered i.t.; P less than 0.05). But the treatment with immune spleen cells was not effective. The incidence and area of necrotic foci in the tumors treated with LAK cells were greater than those of the others. Microautoradiography was also performed using [3H]thymidine-labeled LAK cells, which were administered i.v. to the models on the 14th day after the inoculation of T9. It was revealed that LAK cells accumulated in the lung shortly after the administration and then in the liver and spleen, especially in the white pulp. IL-2 inhibitor activity of the sera from the tumor-bearing rats was greater than that of normal rats (P less than 0.001), but it was depressed markedly by cyclophosphamide (P less than 0.01). The adoptive transfer of LAK cells may be one of the effective treatments of malignant brain tumor. The nature of IL-2 inhibitors is necessary to be clarified for more effective immunotherapy.

Animals↗
PubMed1988

Development of motion analyzing system for implanted tilting disk valves.

A motion-analyzing system was developed to quantitatively evaluate functions of the implanted tilting disk valve, e.g., an open angle and a duration of valve open and/or shut. In this system a picture of the valve on an x-ray cinefilm is displayed on the CRT screen by the TV camera for extraction of valve position. Data extracted are stored in the computer and are used to calculate parameters for motion analysis of the valve. The reliability of this system was confirmed within 3 degrees of error using the valve model prior to the evaluation of cinefilms clinically procured. With the aid of this motion analyzing system, complicated motions of the tilting disk valve were easily quantified and the useful information as given for clinical diagnosis and further valve development.

Computer Graphics↗
PubMed1988

[Analysis of tumor specific immunological response in the patients with malignant brain tumors by the mixed lymphocyte-tumor cell reaction].

In considering immunological approaches to treatment of the patients with malignant brain tumors, it seems very important to enhance the tumor specific immunity. Then, to ascertain whether tumor specific immune response occurs in these patients with malignant brain tumors, lymphocyte blastogenetic responses to tumor cells were examined in 18 patients with malignant brain tumors. Furthermore, to compare the systemic immunological responses with the local responses in the brain tumor tissues, both peripheral blood lymphocyte (PBL) and tumor infiltrating lymphocyte (TIL) were used as blastogenetic stimulators to the tumor cells. The PBL from the patients with malignant gliomas showed any positive blastogenetic response to their own glioma cells in 7 or 12 cases (about 58%). But, TIL from these patients showed a positive response in the only 3 cases (25%). In 6 cases of metastatic brain tumors, otherwise, their PBL showed any positive blastogenetic response to their own tumor cells in 4 of 6 cases (about 67%), and their TIL showed any positive blastogenetic responses in these same 4 cases. So, the tumor specific immunological responses may be stronger in the patient with metastatic brain tumors than in the patient with malignant gliomas. These immunological responses were, furthermore, more weak in the brain tumor tissues than in the systemic immunity. Then, this lymphocyte blastogenetic response to tumor cells were compared with other lymphocyte stimulating examination such as rectine or allogenetic lymphocyte stimulation. Our studies revealed that this lymphocyte blastogenetic response to tumor cells were at lower level compared with rectine such as PHA, PWM, and Con A, or allogenetic lymphocyte stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Effects of cytokines on cultured microvascular endothelial cells derived from gerbil brain].

We studied the effects of cytokines on cultured microvascular endothelial cells derived from gerbil brain. Microvascular endothelial cells were derived from the endothelial cells of gerbil brain. First, effects of tumor necrosis factor (TNF) or [3H] thymidine up-take by the endothelial cells and human smooth muscle cells were studied. After 4 days exposure to TNF, 50 microCi/ml of [3H] thymidine were added to these cells. [3H] thymidine up-take by the endothelial cells were suppressed by adding TNF dose-dependently. Especially, [3H] thymidine up-take by endothelial cells cultured with 1000 U/ml TNF for 4 days were 25 to 62% of the control values. These cells exposed to 1000 U/ml TNF, furthermore, became spindlelike in appearance and over up each other. But, TNF had no effect on human smooth muscle cells. Second, instead of TNF, interferon-gamma (gamma IFN) were studied in the same way. But, [3H] thymidine up-take by the endothelial cells were not effected by adding gamma IFN. Third, the supernatant of the cultured glioma cells were studied in the same way. The supernatants of 6 glioma cells in 8 cases showed TNF like activity to the endothelial cells of gerbil brain. These supernatants, that is, suppressed [3H] thymidine up-take by the endothelial cells over 50%. These suppression were, furthermore, released by adding 50 microliter anti-TNF antibodies. So, we found the cytotoxic effects of TNF on the endothelial cells of gerbil brain. The supernatants of glioma cells, also, showed TNF like activity to the endothelial cells.

Animals↗
PubMed1988

[Observations on the local administration of autologous lymphokine activated killer cells and recombinant interleukin-2 in patients with malignant gliomas].

Recently lymphocytes from patients with cancer have proved to be activated by interleukin 2 (IL-2), and show a strong cytotoxicity. On the basis of this fact, we have tried to inject lymphokine activated killer (LAK) cells and recombinant IL-2 (rIL-2) directly into the cavity of brain tumor. We describe here preliminary results of the local administration of LAK cells and the rIL-2 to patients with malignant gliomas. Lymphocytes from the patients were separated from venous blood on a Ficoll gradient. By culture with rIL-2 for five days, the lymphocytes were activated to generate LAK activity, which was measured by chromium release assay. These LAK cells were capable of killing various kinds of tumor cells including their own cells. For example, their LAK activity to Daudi cell and self tumor cells was approximately 66 and 49%, respectively. These LAK cells showed a strong killing activity in excess of 40 to 70% against various tumor cells. Furthermore, activated killer cells, such as LAK cells, phytohemagglutinin-activated killer cells, and their precursor cells were serologically studied for the recognition of their biological characteristics. The phenotype of these LAK cells were sensitive to Leu 1, 3a, 7, and extremely so to 11 monoclonal antibodies, whereas LAK precursors were mainly sensitive to Leu 11 monoclonal antibodies. This observation led us to think that LAK cells belonged to the polyclonal cell populations. Following the fundamental studies, we applied this adoptive immunotherapy to 12 patients with malignant gliomas in whom standard therapy turned to be unsuccessful. All patients had histological evidence and progressive disease in spite of standard radiochemotherapy and other treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Study on adoptive immunotherapy for experimental brain tumor].

Adoptive immunotherapy for the experimental murine brain tumor has been investigated using LAK cells generated in vitro from normal spleen cells with IL-2 and immune spleen cells from Fischer rats immunized against syngenic gliosarcoma, T9. IL-2 inhibitor(s) activity in serum was also studied. LAK cells and immune spleen cells were adoptively transferred to the rats intravenously or intratumorally on the 7th day after the inoculation of T9 into the right basal ganglia. Then the survival rate and necrotic foci were compared between the groups treated with those cells and the control. The survival rate of the groups treated with LAK cells was significantly higher than that of the control (administrated intravenously; P less than 0.01, administrated intratumorally; P less than 0.05). But the treatment with immune spleen cells was not effective. The incidence and area of necrotic foci in the tumors treated with LAK cells were greater than those of the others. Microautoradiography was also performed using 3H-TdR labeled LAK cells, which were administrated intravenously to the model. It was revealed that LAK cells accumulated in lung shortly after the administration, then in liver and spleen, especially in the white pulp. IL-2 inhibitor activity of the sera from the tumor-bearers was greater than that of normal rats, while it was depressed markedly by cyclophosphamide (60 mg/kg i.p.). In conclusion, the adoptive transfer of LAK cells can be one of the effective and attractive treatments of the brain tumor. In order to make immunotherapy more effective it should be necessary to clarify the nature of IL-2 inhibitor(s).

Animals↗