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1.
Biochemical Study on the Critical Period for Treatment of the Mottled Brindled Mouse 总被引:2,自引:0,他引:2
Hemizygous mottled brindled mice (Mobr/y mice) were treated by subcutaneous injection of copper and were decapitated on postnatal day 14. Cytochrome c oxidase (COX) activity of the brain mitochondria in the mice given 10 micrograms of copper/g on day 4 or 7 showed significant increases compared with that of untreated Mobr/y animals, and these mice had no neurological symptoms. Mice given 10 micrograms of copper/g on day 12 showed neither increases in COX activity nor clinical improvement. The brain levels of copper, noradrenaline, and dopamine in the mice treated on day 12 were the same as those in animals treated on day 4 or 7. The in vitro activities of dopamine-beta-hydroxylase of the brain were also the same among the treated mice, irrespective of the date of treatment. The results indicate that delays in copper treatment produce irreversible changes in COX activity of the brain and lead to clinical unresponsiveness to treatment. 相似文献
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Atsushi Takeda Masatoshi Nakamura Hiroaki Fujii Chihiro Uematsu Tatsuya Minamino Paul A. Adlard Ashley I. Bush Haruna Tamano 《PloS one》2014,9(12)
We examined an idea that short-term cognition is transiently affected by a state of confusion in Zn2+ transport system due to a local increase in amyloid-β (Aβ) concentration. A single injection of Aβ (25 pmol) into the dentate gyrus affected dentate gyrus long-term potentiation (LTP) 1 h after the injection, but not 4 h after the injection. Simultaneously, 1-h memory of object recognition was affected when the training was performed 1 h after the injection, but not 4 h after the injection. Aβ-mediated impairments of LTP and memory were rescued in the presence of zinc chelators, suggesting that Zn2+ is involved in Aβ action. When Aβ was injected into the dentate gyrus, intracellular Zn2+ levels were increased only in the injected area in the dentate gyrus, suggesting that Aβ induces the influx of Zn2+ into cells in the injected area. When Aβ was added to hippocampal slices, Aβ did not increase intracellular Zn2+ levels in the dentate granule cell layer in ACSF without Zn2+, but in ACSF containing Zn2+. The increase in intracellular Zn2+ levels was inhibited in the presence of CaEDTA, an extracellular zinc chelator, but not in the presence of CNQX, an AMPA receptor antagonist. The present study indicates that Aβ-mediated Zn2+ influx into dentate granule cells, which may occur without AMPA receptor activation, transiently induces a short-term cognitive deficit. Extracellular Zn2+ may play a key role for transiently Aβ-induced cognition deficits. 相似文献
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K Watanabe Y Fujii H Ohkubo S Kuramitsu H Kagamiyama S Nakanishi O Hayaishi 《Biochemical and biophysical research communications》1991,181(1):272-278
The full-length bovine lung prostaglandin(PG) F synthase cDNA was constructed from partial cDNA clones and ligated into bacterial expression vector pUC8 to develop expression plasmid pUCPF1. This plasmid permitted the synthesis of bovine lung PGF synthase in Escherichia coli. The recombinant bacteria overproduced a 36-KDa protein that was recognized by anti-PGF synthase antibody, and the expressed protein was purified to apparent homogeneity. The expressed protein reduced not only carbonyl compounds including PGD2 and phenanthrenequinone but also PGH2; and the Km values for phenanthrenequinone, PGD2, and PGH2 of the expressed protein were 0.1, 100, and 8 microM, respectively, which are the same as those of the bovine lung PGF synthase. The protein produced PGF2 alpha from PGH2, and 9 alpha, 11 beta-PGF2 from PGD2 at different active sites. Moreover, the structure of the purified protein from Escherichia coli was essentially identical to that of the native enzyme in terms of C-terminal sequence, sulfhydryl groups, and CD spectra except that the nine amino acids provided by the lac Z' gene of the vector were fused to the N-terminus. These results indicate that the expressed protein is essentially identical to bovine lung PGF synthase. We confirmed that PGF synthase is a dual function enzyme catalyzing the reduction of PGH2 and PGD2 on a single enzyme and that it has one binding site for NADPH. 相似文献
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Cryosurgical hemorrhoidectomy was performed on 171 patients with excellent results achieved in the great majority. The key to successful results is based on the prevention of prolapse of the edematous tissue after freezing. To prevent the edema, it is important to pull out the hemorrhoid as much as possible during the freezing, to freeze only on the rectal side of the anal verge, to carefully avoid freezing the anal verge, and to freeze the hemorrhoids in two or three stages when they are large. Less than satisfactory results were achieved in 11.7% of the patients. The anal discomfort and discharge in these patients were related to prolapse of the frozen tissue. Cryosurgery is an effective method of treatment for hemorrhoids if care is taken to use the proper technique. 相似文献
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Yasuo Kato Yasuhisa Asano Akiko Nakazawa Kiyosi Kondo 《Biocatalysis and Biotransformation》1990,3(3):207-215
Synthesis of D-alanine oligopeptides from D-alanine methylester hydrochloride has been demonstrated by use of immobilized D-aminopeptidase from Ochrobactrum anthropi (Achromobacter sp.) in non-aqueous media. D-Alanine dimer and trimer were obtained in 56% and 6% yield, respectively, when 250 mM of the substrate was incubated for 3 hours with urethane-prepolymer immobilized D-aminopeptidase (1.5 U/ml) and 3 equivalents of triethylamine in water-saturated toluene. The kcat of this reaction was calculated to be 19,500 (min-1), which is several ten thousand times greater than that of the known enzymatic syntheses of amino acid oligomers. 相似文献
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Purified host DNA-suppressing factor (DSF) produced into culture fluid of HeLa C-9 cells infected with measles virus inhibited cellular DNA synthesis in HeLa cells. When purified DSF was added into cultures of synchronous HeLa cells at the early G1-phase, cellular DNA synthesis was irreversibly inhibited. However, DSF did not affect the stability of native double-stranded DNA nor the chain-elongation of single-stranded DNA in cells of the S-phase. 相似文献