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101.
Drake TE 《The Western journal of medicine》1984,141(1):111-113
The use of the do-not-resuscitate order has become accepted medical practice. To date, however, no study has been done of how often it is used or factors associated with its use. Reports of all deaths of inpatients occurring during calendar year 1981 at San Bernardino County Medical Center were eligible for study. Retrospective review of the 237 cases indicated that a do-not-resuscitate order had been written for 165 (69.6%) of the patients. Comparison of reports of those for whom such an order had been written with those for whom no order had been written indicated that a do-not-resuscitate order was not associated with age, sex, ethnicity or pay status. Indices of mental clarity, however, were associated with orders not to resuscitate; those patients residing in nursing homes, and not alert and oriented on admission were overrepresented in the group given this order. Primary discharge diagnosis was also associated with such an order, as was an increased duration of hospital stay. 相似文献
102.
Mice of the PL/J strain exhibit a high percentage of morphologically abnormal sperm and provide a model for studying the function of abnormal sperm. The ability of such sperm to reach the site of fertilization within the female reproductive tract has been investigated. We have found a decrease in the percentage of structurally abnormal sperm within the population that reaches the oviduct. This observation suggests either that there is an active selection against abnormal sperm or that they are physiologically disadvantaged in reaching the site of fertilization. 相似文献
103.
The relaxant actions of vaso-active intestinal polypeptide (VIP), acetylcholine (ACh), histamine and papaverine have been compared using circular muscle strips of rat aorta contracted with noradrenaline (NA). Arachidonic acid (AA) in a low dose (6.7 × 10 − 7M) also relaxed the aorta. The relaxant actions of all these substances except papaverine were abolished by removal of the endothelial cells. Higher doses of AA (6.7–13.4 × 10–6M) contracted aortic strips in the absence of NA but the con tractile effect “faded” while AA was still present in the bathing fluid. De-endothelialisation abolished this “fade” portion of the response leaving a sustained contracture. Indomethacin inhibited the contractile effect of AA revealing a weak inhibitory effect. However, it did not affect the relaxations induced by VIP, ACh, histamine or papaverine. ETYA abolished the relaxant actions of all these substances except papaverine. The results are consistent with the hypothesis that VIP, ACh and histamine relax the rat aorta via an endothelial-dependent mechanism which may involve the synthesis of a lipoxygenase product. 相似文献
104.
105.
1H nuclear magnetic resonance (NMR) spectra at 500 MHz have been obtained for taurocholate/egg phosphatidylcholine mixtures of varying composition. The excellent chemical shift dispersion permits identification of most resonances for each component. This high-resolution character of the NMR spectra is retained until the phosphatidylcholine (PC) mole fraction exceeds 60–70% (the exact limit depends on ionic strength). 1H linewidths have been monitored as a function of solute composition in order to evaluate trends in local molecular mobility of each component as the distribution of aggregate particles is varied, and to examine the effects of added NaCl in altering micellar size and shape. Although prior light scattering studies (Mazer, N.A., Benedek, G.B. and Carey, M.C. (1980) Biochemistry 19, 601–615) and our own work indicate a 6-fold increase in particle hydrodynamic radius from pure taurocholate micelles to 1 : 1 taurocholate/PC mixtures containing 150 mM NaCl, both lipid components retain substantial motional freedom and exhibit narrow NMR signals in this compositional region. As the solubilization limit for PC is approached (approx. 2:1 PC:taurocholate), differential behavior is observed for the two components: the motion of taurocholate becomes preferentially restricted, while polar portions of the PC remain mobile until large multilayers predominate. 相似文献
106.
Isolation and Characterization of a Novel Thermophilic, Freshwater Methanogen 总被引:4,自引:1,他引:3 下载免费PDF全文
A novel thermophilic, coccoid methanogen isolated from nonthermal freshwater sediments is described. Hydrogen plus carbon dioxide and formate were substrates for methanogenesis, and methane production was stimulated by yeast extract, Casamino Acids, and tryptose. Growth also occurred autotrophically. Elevated levels of sodium chloride were not required for maximum growth and were inhibitory above 2%. The minimum doubling time occurred at 57°C, and the upper and lower limits for methane production were 62 and 26°C, respectively. The optimum pH for growth was between 7.0 and 7.5. Inhibitory antibiotics included metronidazole, anisomycin, chloramphenicol, and lasalocid. Colonies were circular, dark yellow, shiny, and convex with entire edges. Cells were 1 to 2.5 μm in diameter, nonmotile, occurring singly or in pairs, and fimbriated. Cells were lysed by pronase or trypsin digestion, glass-distilled water, and 1% sodium dodecyl sulfate. Electron micrographs of thin sections showed a monolayered cell wall ca. 20 nm thick. The DNA base ratio was 49.2 mol% guanine plus cytosine. The whole cell protein pattern differed from that of other named coccoid methanogens. 相似文献
107.
Characterization of a new marine methylotroph 总被引:1,自引:0,他引:1
Abstract A methanol-oxidizing bacterium from a marine environment has been isolated and characterized. The bacterium was a Gram-negative rod, capable of growth on methanol and methylamine, but not on multicarbon compounds. It showed a temperature optimum of 30°C, a salt optimum of 0.4% (w/v) and the mol % G + C of its DNA was 46%. Carbon was assimilated via the ribulose monophosphate pathway for formaldehyde fixation during growth on methanol. This bacterium superficially resembled other obligate methylotrophs requiring NaCl reported previously which were designated Methylomonas thalassica . It also appeared similar to many strains of obligate freshwater methylotrophs, except for its NaCl requirement and its lower mol % G + C. 相似文献
108.
109.
Cell culture of sixteen-day-old rat embryo cerebra and associated changes in ganglioside pattern 总被引:3,自引:3,他引:0
Abstract— Cortical slices from rat brain were incubated in Krebs-Ringer phosphate medium. Activity of the pyruvate dehydrogenase complex (PDH) was measured in homogenates of the incubated tissue. Increasing the extracellular KCI concentration from 5 to 75 mM caused a dose-dependent increase in activity of this rate-limiting mitochondrial enzyme. The increase in PDH activity, produced by high concentration of KCI. was associated with a decrease in the tissue content of ATP. Omission of calcium, or replacement of sodium by choline, reduced, and addition of ouabain prevented, the activation of the enzyme in the depolarized tissue.
The mechanism by which extracellular potassium can affect PDH activity is unknown. However, it is most likely that the alterations in enzyme activity are related to changes in properties of cell membranes during depolarization leading to intracellular events directly affecting the enzyme complex. These could include alterations in the concentrations of adenine nucleotides or free calcium ions in the cell. 相似文献
The mechanism by which extracellular potassium can affect PDH activity is unknown. However, it is most likely that the alterations in enzyme activity are related to changes in properties of cell membranes during depolarization leading to intracellular events directly affecting the enzyme complex. These could include alterations in the concentrations of adenine nucleotides or free calcium ions in the cell. 相似文献
110.
We examined the effects of isopropanol (ISOP) pretreatment on the metabolism of 14CCl4 to 14CO2 and CHCl3 exhaled in the breath, to 14C metabolite excreted in 24 hr urine and feces from 0 to 24 hr, and to 14C metabolite bound to liver at 24 hr. Fasted male rats were given 0.1 or 2.0 mmoles 14CCl4/kg. ISOP pretreatment, which markedly enhanced the hepatotoxicity of CCl4, selectively enhanced the rate and total extent of 14CO2 and CHCl3 metabolite exhalation. The pathways of CCl4 metabolism leading to CO2 and CHCl3 metabolite formation may be more relevant to the hepatotoxicity of CCl4 than the pathways leading to urinarym fecal or covalently bound metabolites. 相似文献