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991.
Fertilization of human eggs in vitro: morals, ethics and the law 总被引:2,自引:0,他引:2
R G Edwards 《The Quarterly review of biology》1974,49(1):3-26
992.
Phenethylamines in brain and liver of rats with experimentally induced phenylketonuria-like characteristics 总被引:3,自引:0,他引:3
1. Phenethylamines were extracted from brain and liver of rats with phenylketonuria-like characteristics produced in vivo by inhibition of phenylalanine hydroxylase (EC 1.14.3.1) with p-chlorophenylalanine, with or without phenylalanine administration. To protect amines against oxidation by monoamine oxidase, pargyline was also administered. 2. beta-Phenethylamine was the major compound found in brain and liver. beta-Phenethanolamine and octopamine were also present, in lesser amounts, and the concentrations of these three amines paralleled blood phenylalanine concentrations. By comparison, tissues from control animals had only very low concentrations of these amines. 3. Small amounts of normetadrenaline, m-tyramine and 3-methoxytyramine were also found. 4. The inhibitors used, p-chlorophenylalanine and pargyline, gave rise to p-chlorophenethylamine and benzylamine respectively, the first via decarboxylation, the second probably by breakdown during extraction. 5. Distribution of phenethylamines in different brain regions and in subcellular fractions of rat brain cells was also investigated. The content of phenethylamine was highest in the striatum. 6. These findings are discussed in the light of changes occurring in human patients with uncontrolled phenylketonuria. 相似文献
993.
994.
A mutant of Neurospora crassa (cni-1) has been isolated that has two pathways of mitochondrial respiration. One pathway is sensitive to cyanide and antimycin A, the other is sensitive only to salicyl hydroxamic acid. Respiration can proceed through either pathway and both pathways together in this mutant account for greater than 90% of all mitochondrial respiration. The cni-1 mutation segregates as a nuclear gene in crosses to other strains of Neurospora. Absorption spectra of isolated mitochondria from cni-1 show typical b- and c-type cytochromes but the absorption peaks corresponding to cytochrome aa(3) are not detectable. Extraction of soluble cytochrome c-546 from these mitochondria followed by reduction with ascorbate reveals a new absorption peak at 426 nm that is not present in wild-type mitochondria. This peak may be due to an altered cytochrome oxidase with abnormal spectral properties. Mitochondria from cni-1 have elevated levels of succinate-cytochrome c reductase but reduced levels of nicotinamide adenine dinucleotide reduced form cytochrome c reductase and of cyanide- and azide-sensitive cytochrome c oxidase. These studies suggest that the cni-1 mutation results in the abnormal assembly of cytochrome c oxidase so that the typical cytochrome aa(3) spectrum is lost and the enzyme activity is reduced. As a consequence of this alteration, a cyanide-insensitive respiratory pathway is elaborated by these mitochondria which may serve to stimulate adenosine 5'-triphosphate production via substrate level phosphorylation by glycolysis and the Krebs cycle. 相似文献
995.
996.
Peter W. Edwards 《BMJ (Clinical research ed.)》1952,1(4763):868-869
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998.
Virological investigations were undertaken on nasopharyngeal secretions from 186 children who were admitted to the Hospital for Sick Children, Toronto, with acute laryngotracheobronchitis between December 1961 and March 1962. Patients who required tracheotomy for relief of respiratory obstruction were excluded from this series. Myxoviruses which were isolated from 47 patients included the following antigenic types: 29 Parainfluenza-1, four Parainfluenza-2, five Parainfluenza-3 and nine Influenza B. The average duration of hospitalization, 3.0 days, was identical for the 47 virus-positive patients and the entire group of 186 patients. Ages of 135 patients were less than three years.Between November 1960 and March 1962, myxoviruses were isolated from 150 of 445 laryngotracheobronchitis patients. The dominant strain, Parainfluenza-1, was isolated from 119 patients who became ill between November 1960 and April 1961, and between October 1961 and March 1962. Parainfluenza-3 virus was isolated irregularly from patients during both cool and warm months. Influenza B and Parainfluenza-2 isolations were made only during 1961-62 winter. Rising antibody levels in paired sera from 20 of 23 Parainfluenza-1 virus excretors and in four patients who yielded Parainfluenza-3 virus confirmed infection with these agents. 相似文献
999.
1000.