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31.
Difference between effects of sulfur dioxide (SO2) and ozone (O3) on groundnut plants (Arachis hypogaea L.) was studied by use of an exposure system of enzymatically-isolated mesophyll cells. SO2 inhibited photosynthesis of intact groundnut leaves but induced no visible injury on leaves. SO2 also inhibited photosynthesis of isolated mesophyll cells but did not kill the cells, suggesting that SO2 inhibits photosynthesis by attacking rather specifically the photosynthetic apparatus in chloroplasts. O3 inhibited photosynthesis of intact leaves and at the same time induced visible injury corresponding to the extent of photosynthesis
inhibition. O3 also inhibited photosynthesis of isolated mesophyll cells and killed the cells to the extent corresponding to photosynthesis
inhibition, suggesting that O3 inhibits photosynthesis not directly by attacking the photosynthetic apparatus but indirectly by killing cells. Since the
response of intact leaves to each pollutant resembled that of isolated mesophyll cells, the difference between responses of
intact leaves to both pollutants may considerably reflect that of mesophyll cells. 相似文献
32.
Masato Maekawa Kayoko Sudo Masato Kitajima Yukio Matsuura Steven S.-L. Li Takashi Kanno 《Human genetics》1993,92(2):163-168
In northwest European countries maternal age is increasing. This will lead to an increase of the prevalence of Down syndrome conceptuses. Meanwhile, the increased use of prenatal cytogenetic diagnosis (PCD) will lead to a decrease in the prevalence of Down syndrome among livebirths. We were interested to know what the result of these two opposite developments would be in the near future, and we describe here a model to quantify these processes and the resulting livebirth prevalence of Down syndrome. The model is demonstrated for The Netherlands from 1992 to 2001. The predicted livebirth prevalence for The Netherlands in 1992 is 1.36 per 1000. Demographic factors will cause an increase to 1.76 per 1000 in 2001 with present indications for PCD and a utilization ratio of 50%. An increase of the utilization ratio to 90% in 2001 will lead to a prevalence of 1.22 per 1000, a little less than the present prevalence. Alternative screening programs, including maternal serum screening, could lead to a further decrease of the livebirth prevalence. The model described here can be used for evaluation of the consequences of alternative forms of Down syndrome screening. 相似文献
33.
Yoshio Oka Tetsuro Kobayashi Shoichi Fujita Nariaki Matsuura Shigeru Okamoto Hideki Asakawa Atsuo Murata Takesada Mori 《In vitro cellular & developmental biology. Animal》1993,29(7):537-542
Summary A human anaplastic thyroid cancer cell line K-119, derived from a 77-yr-old woman who had developed marked neutrophilia and
underwent surgery for anaplastic thyroid cancer, has been established. The spindlelike and polygonal cells in shape are stably
proliferating since the beginning of its culture 2 yr ago. The cells grow rapidly and the population doubling time is 26 h.
The chromosomes show many abnormalities and many marker chromosomes have been observed. Heterotransplantation of the cells
into nude mice has resulted in the formation of tumors that are histologically interpreted as anaplastic cancer. The most
noteworthy characteristics of the cell line are the many Ki-67-positive cells (86.3%) and that the cell line spontaneously
secretes granulocyte colony-stimulating factor (G-CSF) and releases increased amounts of G-CSF in response to the stimulation
of tumor necrosis factor, interleukin 1α, and interleukin 1β. The conditioned medium obtained from K-119 cells contains an
autocrine factor stimulating the proliferation of themselves. 相似文献
34.
35.
Kenji Matsuura Hideo Takashina 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,616(2)
A gas chromatographic—mass spectrometric method for determining tiopronin, which has a thiol group, in human blood has been described. To prevent the oxidative degradation of tiopronin in the blood, its thiol group was immediately protected by treatment with isobutyl acrylate, which reacted readily with tiopronin in a 0.1 M Na2HPO4 solution (pH 9.1). The reaction was quantitative within 30 min. The blood sample was deproteinized and purified by a combination of liquid—liquid extraction and solid-phase extraction. Finally, the carboxyl moiety of the ester adduct was derivatized to the pentafluorobenzyl ester. The derivatives of tiopronin and the internal standard were analysed with gas chromatography—mass spectrometry. The precision of the method was satisfactory, and the calibration curve had good linearity in the concentration range investigated. The limit of determination of tiopronin in blood was estimated to be ca. 1 ng/ml. 相似文献
36.
37.
H Oritani Y Deyashiki T Nakayama A Hara H Sawada K Matsuura Y Bunai I Ohya 《Archives of biochemistry and biophysics》1992,292(2):539-547
A pyrazole-sensitive carbonyl reductase from pig lung was purified to homogeneity by electrophoretic criteria. Chemical cross-linking study suggested that the native enzyme is a tetramer with a Mr of 103,000, consisting of apparent identical subunits of Mr 24,000. The enzyme reduced aliphatic and aromatic carbonyl compounds with NADPH as a preferable cofactor to NADH and catalyzed the oxidation of secondary alcohols and the aldehyde dismutation in the presence of NAD(P)+. Immunohistochemical study with the antibodies against the enzyme revealed that the enzyme was localized in the ciliated cells, nonciliated bronchiolar cells, Type II alveolar pneumocytes, and the epithelial cells of the ducts of the bronchial glands in the pig lung. In addition to the properties and distribution, the pig lung enzyme was immunochemically similar to the pulmonary enzymes in the guinea pig and mouse. However, the pig enzyme showed the following unusual features. (1) The enzyme exhibited an equatorial specificity in the reduction of 3-ketosteroids; the 4-pro-S hydrogen of NADPH was transferred to the carbonyl carbon atom of 5 alpha- and 5 beta-androstanes, and the respective reduced products were identified as 3 beta- and 3 alpha-hydroxysteroids. (2) Although the NADPH-linked reduction of carbonyl compounds apparently obeyed the Michaelis-Menten kinetics at pH 6.0, the double-reciprocal plots of the velocity vs concentrations of the carbonyl substrates were convex at pH higher than 6.5. The Hill coefficients and [S]0.5 values for the substrates decreased as the pH for reaction increased. The results suggest that the pig enzyme exhibits negative cooperativity with respect to the carbonyl substrates and that the hydrogen ion acts as an allosteric effector abolishing the negative interaction. 相似文献
38.
Motohiro Matsuura Shinji Saito Yoshikazu Hirai Haruki Okamura 《European journal of biochemistry》2003,270(19):4016-4025
Production of nitric oxide (NO) in response to bacterial lipopolysaccharide (LPS) was investigated using cultures of mouse peritoneal exudate cells (PEC) and the macrophage cell line RAW264.7. In the presence of anti-(interferon-gamma) (IFN-gamma), NO production was markedly suppressed in the PEC culture but not in the RAW264.7 culture. In the PEC culture, LPS induced both IFN-gamma production and activation of IFN response factor-1, which leads to the gene expression of inducible NO synthase, but neither was induced in the culture of RAW264.7 cells. In addition to anti-(IFN-gamma), antibodies against interleukin (IL)-12 and IL-18 showed a suppressive effect on LPS-induced NO production in the PEC culture, and these antibodies in synergy showed strong suppression. Stimulation of the PEC culture with IL-12 or IL-18 induced production of IFN-gamma and NO, and these cytokines, in combination, exhibited marked synergism. Stimulation of the culture with IFN-gamma induced production of NO, but not IL-12. The macrophage population in the PEC, prepared as adherent cells, responded well to LPS for IL-12 production, but weakly for production of IFN-gamma and NO. The macrophages also responded well to IFN-gamma for NO production. For production of IFN-gamma by stimulation with LPS or IL-12 + IL-18, nonadherent cells were required in the PEC culture. Considering these results overall, the indirect pathway, through the production of intermediates (such as IFN-gamma-inducing cytokines and IFN-gamma) by the cooperation of macrophages with nonadherent cells, was revealed to play the main role in the LPS-induced NO production pathway, as opposed to the direct pathway requiring only a macrophage population. 相似文献
39.
40.
S Kanegasaki Y Kojima M Matsuura J Y Homma A Yamamoto Y Kumazawa K Tanamoto T Yasuda T Tsumita M Imoto 《European journal of biochemistry》1984,143(2):237-242
Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities. 相似文献