排序方式: 共有67条查询结果,搜索用时 15 毫秒
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M Zorbas R H Kennedy E Seifen 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1988,89(2):333-336
1. Inotropic effects of isoproterenol and extracellular Ca2+ were compared in left atrial muscle isolated from F344 and SD rats. Preparations from the F344 strain were more sensitive to the actions of both agents. 2. The chronotropic action of isoproterenol was not different in right atria isolated from the two strains. 3. This suggests that the strain-related difference in responsiveness to the inotropic effect of isoproterenol is not caused by heterogeneity in the beta-adrenoceptor/adenylate cyclase system but rather by variations in excitation-contraction coupling. 相似文献
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Intense interest in the biological roles of DNA methylation, particularly in eukaryotes, has produced at least eight different methods for identifying 5-methylcytosine and related modifications in DNA genomes. However, the utility of each method depends not only on its simplicity but on its specificity, resolution, sensitivity and potential artifacts. Since these parameters affect the interpretation of data, they should be considered in any application. Therefore, we have outlined the principles and applications of each method, quantitatively evaluated their specificity,resolution and sensitivity, identified potential artifacts and suggested solutions, and discussed a paradox in the distribution of m5C in mammalian genomes that illustrates how methodological limitations can affect interpretation of data. Hopefully, the information and analysis provided here will guide new investigators entering this exciting field. 相似文献
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Bernhard Miller Stefan Wild Haralabos Zorbas Wolfgang Beck 《Inorganica chimica acta》1999,290(2):400-246
Mono- and bis(platinum) complexes containing N-alkyl-ethylenediamine units of the type {cis-PtCl2[H2NCH2CH2NH(CH2)nCH3]} (n=8, 9, 11, 15) and [{cis-PtCl2(H2NCH2CH2NH)}2(CH2)n] (n=6, 8, 10, 12) and their corresponding dihydroxo-platinum(IV) complexes were synthesized. The structures of the metal chelates were derived from elemental analyses and their 1H, 13C, IR spectra. The length of the aliphatic chains has been varied systematically, in order to increase the lipophilicity. Enlargement of the linker could also lead to more flexibility of one platinum sphere in reference to the attached DNA species. Using in vitro cytotoxicity tests it is shown that the biological activity of the bis(platinum) complexes increased, up to n=12, with the length of the linker. The longest linker in the ligands resulted in the most effective bis(platinum) complexes against L1210 murine leukemia cells. 相似文献
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Yan G. Zorbas Nikolai A. Kuznetsov Youri N. Yaroshenko 《Biological trace element research》1997,57(2):169-181
The objective of this investigation was to determine the effect of prolonged restriction of motor activity (hypokinesia [HK])
on several parameters of water metabolism in primates. The studies were performed on 12 rhesus monkeys aged 4–5 yr (5.10–6.85
kg) during the hypokinetic period of 90 d and during the prehypokinetic period of 30 d. They were divided into two equal groups:
the first group was placed under ordinary vivarium conditions (vivarium control animals) and the second group was subjected
to 90 d of HK (hypokinetic animals). For the simulation of the hypokinetic effect, the primates were immobilized on their
abdomens in special tables. The legs of the monkeys were immobilized with hip and knee joints extended. The primates retained
freedom of movement at elbow, wrist, and ankle. During the preexperimental period of 30 d and during the experimental period
of 90 d, the following variables were determined: body weight, total body fluid content, specific total body fluid, mean fluid
consumed and eliminated in urine, specific plasma resistance, hematocrit level, and plasma concentrations of sodium (Na) and
potassium (K). In the hypokinetic primates, body weight decreased significantly when compared to the controls. Mean fluid
intake, total body fluid, and specific total body fluid decreased, whereas mean daily fluid loss and specific mean daily fluid
elimination increased significantly. Specific plasma resistance, hematocrit level, and plasma electrolyte concentrations increased
significantly when compared to the control primates. It was concluded that prolonged restriction of motor activity induces
significant changes in water metabolic parameters of primates leading in decreased total water content of the body. 相似文献