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991.
Fujiko Ozawa Yoshitoshi Kasuya Hiroshi Hama Sachie Asada Tetsuo Inada Katsutoshi Goto 《Journal of neurochemistry》1997,69(2):562-569
Abstract: We investigated the effect of cytoskeleton modulators on endothelin-B (ETB ) receptor expression in rat primary cultured astrocytes. Northern blot analysis and a binding study revealed that colchicine and nocodazole, microtubule-disrupting agents, decreased the levels of both ETB receptor mRNA and the number of ET-1 binding sites in quiescent astrocytes. Down-regulation of both ETB receptor mRNA and the number of binding sites for ET-1 was also observed in quiescent astrocytes treated with taxol, a microtubule-stabilizing agent. In contrast, neither β-lumicolchicine, an inactive isomer of colchicine, nor cytochalasin D, a microfilament-disrupting agent, influenced ETB receptor expression. The level of ETB receptors in astrocytes was affected by the cell state, namely, proliferative, quiescent, or differentiated state. The order of ETB receptor expression according to the cell state was proliferative state < quiescent state ≪ differentiated state induced by dibutyryl cyclic AMP. Also, in proliferative astrocytes and differentiated astrocytes, colchicine significantly down-regulated both ETB receptor mRNA and the number of binding sites for ET-1. However, thymidine assay revealed that colchicine did not change quiescent astrocytes and differentiated astrocytes to a proliferative state. Furthermore, the increase in glutamine synthetase activity in differentiated astrocytes was not affected by colchicine. These results suggest that microtubule dynamics possibly regulates ETB receptor expression in astrocytes without affecting the cell state. 相似文献
992.
M. Iino S. Ciani K. Tsuzuki S. Ozawa Y. Kidokoro 《The Journal of membrane biology》1997,155(2):143-156
Ion permeation properties of the mouse e2/ζ1 NMDA receptor channel expressed in Xenopus oocytes were studied using the outside-out patch-clamp technique. In symmetrical Na+ solutions, the single-channel I-V relations were almost linear at low electrolyte concentrations, but rectified inwardly for Na+ concentrations above 50 mm. In symmetrical Na+ solutions, the ``zero-current conductance' increased with Na+ concentration and saturated according to a hyperbolic curve, the half-maximal saturating activity, K
M
(Na), being 14.2 mm and the maximal conductance, G
max(Na), 53.9 pS. When Ca2+ was present with Na+ in the external solution, the single-channel current was lower than in pure Na+, although the reversal potential indicated a higher permeability for Ca2+ than for Na+. Using ion activities, PCa/PNa was found to be about 17. The I-V data were fitted with a model based on the Eyring's rate theory, assuming a one-ion pore with three energy barriers and two
sites. The K
M
(Ca) and G
max (Ca) were 76.5 μm and 21.2 pS, respectively. According to the estimated rate constants, K
M
for Ca2+ is mainly determined by the binding strength of a site located 80% away from the channel opening at the external membrane-solution
interface, a position similar to that postulated previously for the Mg2+ blocking site.
Received: 3 May 1996/Revised: 25 September 1996 相似文献
993.
Miyako Kabasawa Sadakazu Ejiri Kooji Hanada Hidehiro Ozawa 《Biotechnic & histochemistry》1995,70(2):66-69
To investigate the time course of mineralization in undecalcified dental tissues, calcein-and tetracycline-labeled rat maxillary molar sections were stained with Villanueva bone stain en bloc, embedded in methyl-methacrylate (MMA), ground to 50 μm thickness, and observed by confocal laser scanning microscopy (CLSM). This method allowed observation of dental structures including odontoblasts, pulp cells and periodontal ligament, and dentinal tubules and enamel rods at high resolution; labeled enamel, dentine, and cementum could be observed simultaneously regardless of section thickness. CLSM permitted simultaneous observation of both the components of calcified tissue and the cellular components of dental tissues, and assessment of the mineralization time course of hard tissues labeled by tetracycline or calcein. The technique is useful for both assessing the elements composing dental structure and observing the histological dynamics by which dental structure develops. 相似文献
994.
Isolation and characterization of linear deoxyribonucleic acid plasmids from Kluyveromyces lactis and the plasmid-associated killer character. 总被引:36,自引:9,他引:27
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Two linear deoxyribonucleic acid plasmids, designated pGK11 and pGK12, were isolated from the yeast Kluyveromyces lactis IFO 1267. pGK11 and pGK12 had molecular weights of 5.4 X 10(6) and 8.4 X 10(6), respectively. Both plasmids possessed the same density of 1.687 g/cm3, lighter than the densities of mitochondrial (1.692 g/cm3) and nuclear (1.699 g/cm3) deoxyribonucleic acids. A restriction map of pGK11 was constructed from digestions by EcoRI, HindIII, PstI, and BamHI. pGK12 was cleaved by EcoRI into seven fragments and by BamHI into two fragments K. lactis IFO 1267 killed Saccharomyces cerevisiae sensitive and killer strains and certain strains of Saccharomyces italicus, K. lactis, Kluyveromyces thermotolerans, and K. vanudenii. All K. lactis strains lacking the pGK1 plasmids were nonkillers. A hybrid was constructed between K. lactis IFO 1267 and a nonkiller K. lactis strain lacking the plasmids and subjected to tetrad analysis after sporulation. The killer character was extrachromosomally transmitted in all tetrads in association with the pGK1 plasmids. The double-stranded ribonucleic acid killer plasmid could not be detected in any K. lactis killer strains. It is thus highly probable that the killer character is mediated by the linear deoxyribonucleic acid plasmids. A single chromosomal gene was found which was responsible for the resistance to the K. lactis killer. 相似文献
995.
When a plasma membrane preparation isolated from rat liver was incubated with [gamma-32P]ATP and Mg2+, protein-bound 32P increased rapidly, followed by a gradual decrease. The time course suggested the existence of membrane-bound kinase(s) and phosphatase(s) phosphorylating and dephosphorylating endogenous proteins. The extent of phosphorylation was not affected by inclusion of cyclic AMP in the reaction mixture. The extent of the maximum phosphorylation was dependent on membrane concentration, owing to rapid hydrolysis of ATP by the membrane-bound ATPase activity. Thus, phosphorylation proceeded further on repeated addition of ATP. Both phosphorylation and dephosphorylation were stimulated by Mg2+, an effective rate of phosphorylation being obtained at 15 mM. Pi up to 20 mM stimulated phosphorylation with little effect on the rate of dephosphorylation. At higher phosphate concentrations, the maximum 32P-incorporation decreased again, and at 100 mM, dephosphorylation was prevented significantly. Autoradiography after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and urea revealed six main phosphorylated bands, two of which (Band 3 and 5) were partly extractable with 1 M NaCl. In the presence of 100 mM Pi, very strong phosphorylation of Band 5 (about 23,000 daltons) was noted, and a new strongly labeled band (Band P, about 20,000 daltons) was observed. It was concluded that the phosphoproteins in the membrane may be turned over at different rates and high concentrations of Pi may affect the turnover rate of some phosphoproteins, probably through interference with the phosphatase. 相似文献
996.
Nghi Ngoc Tran Tai The Pham Kyoko Ozawa Muneko Nishijo Anh Thi Nguyet Nguyen Tuong Quy Tran Luong Van Hoang Anh Hai Tran Vu Huy Anh Phan Akio Nakai Yoshikazu Nishino Hisao Nishijo 《PloS one》2016,11(1)
Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder. 相似文献
997.
BackgroundDespite accounting for approximately one fifth of all acute gastroenteritis illnesses, norovirus has received comparatively less attention than other infectious pathogens. With several candidate vaccines under development, characterizing the global economic burden of norovirus could help funders, policy makers, public health officials, and product developers determine how much attention and resources to allocate to advancing these technologies to prevent and control norovirus.MethodsWe developed a computational simulation model to estimate the economic burden of norovirus in every country/area (233 total) stratified by WHO region and globally, from the health system and societal perspectives. We considered direct costs of illness (e.g., clinic visits and hospitalization) and productivity losses.ResultsGlobally, norovirus resulted in a total of $4.2 billion (95% UI: $3.2–5.7 billion) in direct health system costs and $60.3 billion (95% UI: $44.4–83.4 billion) in societal costs per year. Disease amongst children <5 years cost society $39.8 billion, compared to $20.4 billion for all other age groups combined. Costs per norovirus illness varied by both region and age and was highest among adults ≥55 years. Productivity losses represented 84–99% of total costs varying by region. While low and middle income countries and high income countries had similar disease incidence (10,148 vs. 9,935 illness per 100,000 persons), high income countries generated 62% of global health system costs. In sensitivity analysis, the probability of hospitalization had the largest impact on health system cost estimates ($2.8 billion globally, assuming no hospitalization costs), while the probability of missing productive days had the largest impact on societal cost estimates ($35.9 billion globally, with a 25% probability of missing productive days).ConclusionsThe total economic burden is greatest in young children but the highest cost per illness is among older age groups in some regions. These large costs overwhelmingly are from productivity losses resulting from acute illness. Low, middle, and high income countries all have a considerable economic burden, suggesting that norovirus gastroenteritis is a truly global economic problem. Our findings can help identify which age group(s) and/or geographic regions may benefit the most from interventions. 相似文献
998.
999.
1000.
Theresa?Frank Anna?Reichel Olav?Larsen Anne-Charlotte?Stilp Mette?M.?Rosenkilde Thomas?Stamminger Takeaki?Ozawa Nuska?TschammerEmail authorView authors OrcID profile 《Cell communication and signaling : CCS》2016,14(1):31