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61.
Toshiaki Koizumi Toshiki Yokota Mikiko Fukuchi Hideki Tatsumoto Yasuhiro Yamane 《Cell biology and toxicology》1991,7(4):357-369
In order to clarify the protective mechanism of sodium molybdate against the acute toxicity of cadmium chloride in rat, the effect of in vivo sodium molybdate pretreatment on the cytotoxic action of cadmium in isolated hepatocytes was studied. The cytosolic pH of hepatocytes isolated from untreated rats immediately decreased with incubation in either neutral Hank's balanced salt solution (HBS), pH 7.4, containing 5 µM cadmium chloride minimum or acidic HBS (pH 7.1, 6.8, 6.5, and 6.2). The presence of 5 µM cadmium in HBS adjusted to pH 7.1 aggravated cytosalic acidification induced by the acidic medium alone. Cell viability of hepatocytes incubated in HBS at pH 6.2 was significantly reduced as compared to that of control cells in HBS at pH 7.4, but the presence of cadmium in the acidic HBS had no aggravating action against such a toxic action of the acidic medium although cellular uptake of the metal in the medium increased, as compared to that in HBS at pH 7.4. Molybdenum pretreatment alleviated cytoplasmic acidification induced by the treatment with HBS at pH 7.4 or 7.1 containing cadmium or by extracellular acid load wothout cadmium. This pretreatment also prevented the loss of cell viability induced by the treatment with HBS at pH 6.2 but could not attenuate that when cadmium was present in the medium.These facts suggest that molybdenum pretreatment alleviated the acute toxicity of cadmium in rat by preventing cytoplasmic acidification caused by the harmful metal. 相似文献
62.
63.
Differentiation of extracutaneous melanocytes in embryos of the turtle, Trionyx sinensis japonicus. 总被引:1,自引:0,他引:1
L Hou T Takeuchi 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》1991,4(4):158-162
The present study investigates the mode of differentiation of neural crest-derived melanocytes in the embryos of the soft-shell turtle, Trionyx sinensis japonicus. DOPA reaction-positive melanoblasts were first detected in 10-day-old embryos. Melanocyte differentiation in terms of pigmentation takes place from the day 16 of development. Melanin pigments were found in the dorsal integument as well as in various extracutaneous tissues such as skeletal muscle, dorsal aorta, peritoneum, blood vessels, choroid, lung, bone marrow, fat tissues and in the connective tissue of the nose. These results suggest the presence of a specific environmental regulation of the melanoblast differentiation in the soft-shell turtle. 相似文献
64.
Masamitsu Honma Eiko Kataoka Kiyokata Ohnishi Tadao Ohno Masao Takeuchi Nobuo Nomura Hiroshi Mizusawa 《In vitro cellular & developmental biology. Animal》1992,28(1):24-28
Summary Using the polymorphic DNA probes, ChdTC-15, ChdTC-114, pYNH24, and λTM-18, a DNA profiling system was developed that verified
identities of individual cultured cell lines collected in the Japanese cell banks, JCRB, RCB, and IFO. These highly polymorphic
DNA probes include both VNTR (Variable Number of Tandem Repeats) sequences and substantial lengths of unique regions. In the
mixed probe system, several distinct bands from four to eight can be used for cell line identification. These bands were widely
spread in a range of molecular sizes, and were stable and reproducible under stringent conditions of Southern blot hybridization.
Because the DNA profile was specific for each individual human cell line, it is useful not only to authenticate many existing
cultured cell lines but also to monitor their identity during propagation in a laboratory, and to confirm newly established
lines as unique. 相似文献
65.
Inhibition of epidermal growth factor-induced DNA synthesis by tyrosine kinase inhibitors 总被引:10,自引:0,他引:10
Kazuo Umezawa Takashi Hori Hirohisa Tajima Masaya Imoto Kunio Isshiki Tomio Takeuchi 《FEBS letters》1990,260(2):201-205
We prepared methyl 2,5-dihydroxycinnamate as a stable analogue of erbstatin, a tyrosine kinase inhibitor. This analogue was about 4 times more stable than erbstatin in calf serum. It inhibited epidermal growth factor receptor-associated tyrosine kinase in vitro with an IC50 of 0.15 μg/ml. It also inhibited in situ autophosphorylation of epidermal growth factor receptor in A431 cells. Methyl 2,5-dihydroxycinnamate was shown to delay the S-phase induction by epidermal growth factor in quiescent normal rat kidney cells, without affecting the total amount ofDNA synthesis. The effect of erbstatin on S-phase induction was smaller, possibly because of its shorter life time. 相似文献
66.
T. Itoh M.D. S. Kasahara S. Aizu K. Kato M. Takeuchi T. Mori 《Cell and tissue research》1982,226(3):469-476
Summary In the monolayer of an established epithelial cell line from the rat thymus, IT-26R21, characteristic cell aggregates quite similar to Hassall's corpuscles were formed. These aggregates were examined by light and electron microscopy, and immunohistochemically. Their interpretation as Hassall's corpuscles is based on the following observations: (1) The aggregates are formed in the monolayer of cells that greatly resemble medullary epithelial cells of the thymus. (2) They consist of flattened epithelial cells in a concentric pattern with one or more degenerating cells in the center. (3) Loss of microvilli suggests that these cells are keratinizing. (4) The aggregates show strongly positive reactions in immunofluorescent staining with antikeratin and antiprekeratin.When Hassall's corpuscles increase in size, cellular proliferation is somewhat suppressed. Both in vivo and in vitro, they may be interpreted as an expression of a changing growth pattern in confined spaces and thus seem to have little immunological function. 相似文献
67.
Differences between smooth and skeletal muscle myosins in their interactions with F-actin 总被引:1,自引:0,他引:1
K Takeuchi 《Journal of biochemistry》1982,91(3):1001-1007
Myosin and F-actin were prepared from bovine carotid arterial smooth muscle and the properties of the binding of myosin to F-actin were compared with those of the binding of skeletal muscle myosin to F-actin. The following differences were observed between skeletal and smooth muscle myosins. 1. The rate of ATP-induced dissociation of arterial actomyosin was equal to that of hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin, but was much lower than those of skeletal muscle actomyosin and of hybrid actomyosin reconstituted from skeletal muscle myosin and arterial F-actin. 2. The amount of ATP necessary for complete dissociation of arterial actomyosin was 2 mol/mol of myosin, although it is well known that skeletal muscle actomyosin is dissociated completely by the addition of 1 mol ATP per mol of myosin. 3. Arterial actomyosin and hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin did not dissociate upon addition of 0.1 mM PPi, while skeletal muscle actomyosin dissociated completely. 4. In the absence of Mg2+, neither dissociation by ATP nor ATPase [EC 3.6.1.3] activity was observed with arterial actomyosin and hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin. On the other hand, skeletal muscle actomyosin dissociated almost completely upon addition of ATP and showed a considerably high ATPase activity. These observations reveal marked differences between myosins from skeletal and smooth muscles in their binding properties to F-actin. 相似文献
68.
Protoplasts prepared from suspension-cultured Vinca rosea cellswere cultured for 5 days. The cell walls regenerated from theprotoplasts were mainly composed of glucans having 1,3- and1,4-linkages. To investigate the molecular species, these glucanswere separated into four fractions: EDTA (50 mM, pH 4.5)-soluble(fraction E), KOH (24%)- soluble but not precipitatable by neutralizationwith acetic acid (fraction K-S), KOH (24%)-soluble and precipitatableby neutralization with acetic acid (fraction K-P), and KOH (24%)-insoluble(fraction C). By means of sugar composition analysis, methylationanalysis, periodate oxidation and enzymatic digestion, the molecularspecies of the glucans contained in the regenerated cell wallswere deduced to be ß-1,4-glucan (cellulose) and ß-1,3-glucan.Fraction C was mainly composed of ß-1,4-glucan; ß-1,3-glucanwas mainly recovered in fraction K-P. The ß-l,3-glucanwas soluble in dilute alkali solution, but was only slightlysoluble in water. The ß-1,3-glucan had an essentiallyunbranched structure, and its weight average molecular weightestimated by gel permeation chromatography was 4.55.0x 104.
1 Present address: Division of Environmental Biology, NationalInstitute for Environmental Studies, Yatabe, Tsukuba, Ibaraki305, Japan (Received May 21, 1981; Accepted October 13, 1981) 相似文献
69.
70.
Eiji Ichishima Yoshinori Tsuruda Taro Ushijima Takehiko Nomi Shoji Suzuki Michio Takeuchi Akiko Yamane 《Current microbiology》1980,4(2):85-89
The enzymological, physical, and immunological properties of soluble and bound forms of intracellular acid carboxypeptidase
isolated from fresh mycelia ofAspergillus saitoi are reported. In the broken mycelia, about 60% of the total activity was found in the 2,000×g precipitate, with most of the remainder in the 100,000×g supernantant. The highly purified enzymes, Ia and Ib, from the 100,000×g supernatant were found to be homogeneous by such criteria as disc gel electrophoresis at pH 9.4 The bound enzyme, II, was
solubilized from the 2,000×g precipitate by self-digestion at pH 6.4 and was highly purified by chromotography. The two forms of intracellular enzymes,
the soluble enzymes (Ia and Ib) from the 100,00×g supernatant and the solubilized enzyme (II) from the 2,000×g precipitate, were closely related to, but not completely identical with, the extracellular acid carboxypeptidase. 相似文献