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41.
In normal male rabbits loaded dietary cholesterol, intravital-microscopy revealed a marked acceleration of intravascular adhesiveness of white blood cells and aggregability of red blood cells and a swarming of lipid-laden macrophages in connective tissue space concurrently with a systemic hyperlipidemia and anemia. Possible roles of the microcirculatory changes in the atherogenesis were discussed. 相似文献
42.
The antibody responses to membrane and early antigens and thymidine kinase of varicella-zoster virus (VZV) were studied in sera during both varicella and zoster by a test with fluorescent antibody to membrane antigen (FAMA), staining the biochemically transformed cells by the immunofluorescent technique and neutralization of virus-specific thymidine kinase activity, respectively. Similar increases in FAMA antibody titers were demonstrated in sera from patients with varicella and zoster. IgM was detected in both groups, but appeared earlier during varicella than during zoster. Furthermore, the antibody titers to early antigens and virus-specific thymidine kinase were higher in patients with zoster than in those with varicella. These data suggest that different types of antibody responses occur during varicella and zoster. 相似文献
43.
Enhancement of ATPase Activity by a Lipid Peroxide of Arachidonic Acid in Rat Brain Microvessels 总被引:5,自引:5,他引:0
Tohru Koide Takao Asano Hiroshi Matsushita Kintomo Takakura 《Journal of neurochemistry》1986,46(1):235-242
The effects of 15-hydroperoxyarachidonic acid (15-HPAA) on Na+, K+- and Mg+-ATPase activities in the blood-brain barrier (BBB) were examined using rat brain microvessels (MV). 15-HPAA markedly stimulated these ATPase activities in MV at low concentrations whereas the synaptosomal Na+, K+-ATPase activity was inhibited in a dose-dependent manner. Further neurochemical analysis revealed that this stimulatory effect of 15-HPAA in MV was not due to a simple detergent-like action of the compound on the membranes but rather to stimulation of the phospholipase A2 and lipoxygenase activity within MV. In addition, it was shown that free radical reactions were involved in the mechanism. Since such anti-edema drugs as 1,2-bis(nicotinamido)propane were proved to be potent suppressors of the enhanced ATPase activity, further speculations on the role of this effect for ischemic brain edema are offered. 相似文献
44.
3-Ketovalidoxylamine A C-N lyase of Flavobacterium saccharophilum is a monomeric protein with a molecular weight of 36,000. Amino acid analysis revealed that the enzyme contains 5 histidine residues and no cysteine residue. The enzyme was inactivated by diethylpyrocarbonate (DEP) following pseudo-first order kinetics. Upon treatment of the inactivated enzyme with hydroxylamine, the enzyme activity was completely restored. The difference absorption spectrum of the modified versus native enzyme exhibited a prominent peak around 240 nm, but there was no absorbance change above 270 nm. The pH-dependence of inactivation suggested the involvement of an amino acid residue having a pKa of 6.8. These results indicate that the inactivation is due to the modification of histidine residues. Substrates of the lyase, p-nitrophenyl-3-ketovalidamine, p-nitrophenyl-alpha-D-3-ketoglucoside, and methyl-alpha-D-3-ketoglucoside, protected the enzyme against the inactivation, suggesting that the modification occurred at or near the active site. Although several histidine residues were modified by DEP, a plot of log (reciprocal of the half-time of inactivation) versus log (concentration of DEP) suggested that one histidine residue has an essential role in catalysis. 相似文献
45.
Tatsuo Nakahara Takashi Matsumoto Makoto Hirano Hideyuki Uchimura Hideyasu Yokoo Kaoru Nakamura Kenji Ishibashi Hitoshi Hirano 《Peptides》1985,6(6):1093-1099
Acute and chronic effects of γ-butyrolactone-γ-carbonyl-histidyl-prolinamide (DN-1417) were investigated on motor activity, dopamine (DA) metabolites and DA receptors in various brain regions of rats. The motor activity, as measured with Automex recorder, was enhanced after a single injection with DN-1417 (20 mg/kg, IP), and the motor stimulating action persisted during 21 daily injections. Acute DN-1417 elevated both homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in 7 brain regions, prefrontal cortex polar, medial and lateral fields, nucleus accumbens, olfactory tubercles, amygdala and striatum. After chronic treatment for 7 days, the acute effect of DN-1417 on DA metabolites disappeared in all regions except for the striatum in which DN-1417 still increased HVA and DOPAC. The response of striatal DA metabolites was also observed after chronic treatment for 21 days. Chronic DN-1417 produced no significant change in 3H-spiperone binding in the prefrontal cortex, nucleus accumbens, olfactory tubercles and striatum, while striatal 3H-DA binding displaced by 30 nM spiperone was enhanced after chronic treatment. These results indicate that DN-1417 interacts with mesocortical, mesolimbic and nigrostriatal DA systems in the different modes of action. The lack of tolerance to motor hyperactivity, however, raises the question as to whether DN-1417-induced hyperactivity may be mediated by the activation of mesolimbic DA neurons. The involvement of nigrostriatal neurons in DN-1417-induced motor hyperactivity is suggested. 相似文献
46.
Kihachi Saito Kenji Ishii Norihisa Fujita Masanobu Nakahiro Reizo Inoki 《Neurochemistry international》1985,7(6):1033-1036
Two parameters of Ca2+ dynamics in brain preparations (45Ca-uptake to slices and [3H]nitrendipine binding to membrane fractions) were measured in naive and chronic morphine-administered rats. While morphine did not have any effect on 45Ca-uptake to striatal slices in normal Krebs-Ringer solution, it inhibited K+-stimulated 45Ca-uptake to slices. Furthermore, the effect of morphine was antagonized by naloxone. Inhibition of K+-stimulated 45Ca-uptake to striatal slices by morphine was not observed in preparations obtained from chronic morphine-administered rats (6 mg/kg/b.i.d./7 days). In membrane fractions, [3H]nitrendipine binding increased by 34% in striatum following chronic morphine treatment, whereas no change was observed in the cortex and hippocampus. The results will be discussed in relation to the phenomena underlying chronic morphine administration. 相似文献
47.
Leucine dehydrogenase (l-leucine: NAD+ oxidoreductase, deaminating, EC 1.4.1.9) has been purified to homogeneity from a moderate thermophilic bacterium, Bacillus stearothermophilus. Am improved method of preparative slab gel electrophoresis was used effectively to purify it. The enzyme has a molecular mass of about 300,000 and consists of six subunits with identical molecular mass (Mr, 49,000). The enzyme does not lose its activity by heat treatment at 70° C for 20 min, and incubation in the pH range of 5.5–10.0 at 55° C for 5 min. It is stable in 10 mM phosphate buffer (pH 7.2) containing 0.01% 2-mercaptoethanol at over 1 month, and is resistant to detergent and ethanol treatment. The enzyme catalyzes the oxidative deamination of branched-chain l-amino acids and the reductive amination of their keto analogs in the presence of NAD+ and NADH, respectively, as the coenzymes. The pH optima are 11 for the deamination of l-leucine, and 9.7 and 8.8 for the amination of -ketoisocaproate and -ketoisovalerate, respectively. The Michaelis constants were determined: 4.4 mM for l-leucine, 3.3 mM for l-valine, 1.4 mM for l-isoleucine and 0.49 mM for NAD+ in the oxidative deamination. The B. stearothermophilus enzyme shows similar catalytic properties, but higher activities than that from Bacillus sphaericus.Dedicated to Prof. Dr. G. Drews on the occasion of his 60th birthday 相似文献
48.
The properties and application of l-methionine γ-lyase [methioninase, l-methionine methanethiol-lyase (deaminating), EC 4.4.1.11], a pyridoxal 5′-phosphate enzyme, purified from Pseudomonas putida and Aeromonas sp. are presented. The enzyme has multicatalytic functions: it catalyses α,γ-elimination and γ-replacement reactions of l-methionine and its analogues (e.g. ethionine, homocysteine, O-acetylhomoserine and selenomethionine), α,β-elimination and β-replacement reactions of l-cysteine and its analogues (e.g. S-methylcysteine, O-acetylserine and Se-methylselenocysteine), deamination and γ-addition of vinylglycine, and deuterium labelling at the α and β positions of l-methionine and other straight-chain l-amino acids. These reactions are applicable to the synthesis of various optically active sulphur and selenium amino acids, preparation of deuterium or tritium labelled l-amino acids, and determination of sulphur amino acids. In addition, the enzyme shows potent anti-neoplastic activity. 相似文献
49.
Toshihisa Ohshima Christian Wandrey Miyuki Sugiura Kenji Soda 《Biotechnology letters》1985,7(12):871-876
Summary Screening of leucine and alanine dehydrogenases in thermophilicBacillus strains was carried out to develop their utilization for industrial and analytical catalysts. Out of the 28 thermophilic strains tested, four strains,Bacillus sp. DSM 405, 730 and 1521, andB.
sphaericus DSM 462, abundantly produce both the enzymes. Both the enzyme activities in these thermophiles are enhanced by addition of the substrates to a polypeptone medium. 相似文献
50.
SV40 vector with early gene replacement efficient in transducing exogenous DNA into mammalian cells.
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An early replacement SV40 vector, SV40-Mu beta, was constructed by replacing part of the early genes of the virus with mouse interferon-beta (IFN-beta) cDNA. Upon transfection of COS-7 cells with this DNA, transducing viral particles were produced, which could infect various cells and cause efficient production of mouse IFN-beta. The viral stock contained no detectable wild-type SV40. The IFN production after the virus infection was very high in monkey kidney cells, but less so in human epithelial cells, and low in mouse, pig, hamster cells and in human lymphocytes. The efficiency of introduction of the DNA to monkey kidney cells was compared with that by the calcium phosphate precipitation method, and the viral vector was found to be more efficient by a factor of several tens to hundreds. 相似文献