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Rat liver microsomes and, to a lesser extent, nuclei were previously shown to produce reactive oxygen species at elevated rates after chronic ethanol treatment. The ability of intact rat liver mitochondria to interact with iron and either NADH or NADPH, and the effects of ethanol treatment, on production of reactive oxygen intermediates was determined. In the presence of ferric-ATP, NADH or NADPH catalyzed mitochondrial lipid peroxidation. Rates were elevated two- to threefold with mitochondria from ethanol-fed rats with both reductants. Mitochondrial lipid peroxidation was insensitive to superoxide dismutase, catalase, or hydroxyl radical scavengers but was sensitive to GSH and anti-oxidants such as trolox. Mitochondrial generation of hydroxyl radical-like species (assayed by oxidation of chemical scavengers) was increased after chronic ethanol treatment, as was H2O2 production. Modifiers of mitochondrial metabolism such as rotenone, cyanide, or an uncoupling agent, had no effect on mitochondrial production of reactive oxygen intermediates. The membrane-impermeable thiol reagent, p-chloromercuribenzoate, was complete inhibitory with both mitochondrial preparations. The activity of the rotenone-insensitive NADH-cytochrome c reductase, an enzyme of the outer mitochondrial membrane, was increased 40 to 60% by the ethanol treatment. These results suggest that NADH acting via the outer membrane NADH reductase can catalyze an iron-dependent production of oxygen radicals by rat liver mitochondria. The outer mitochondrial membrane fraction, prepared by digitonin fractionation, displayed increased rotenone-insensitive NADH-cytochrome c reductase activity after ethanol treatment and was more reactive in catalyzing scission of pBR322 DNA from the supercoiled form to the open circular forms. Rates of oxygen radical production by mitochondria and the extent of increase produced by chronic ethanol treatment are similar to those previously found with microsomes when NADH is the cofactor. Oxidation of ethanol by alcohol dehydrogenase generates NADH, and NADH-dependent production of reactive oxygen species by various organelles is increased after chronic ethanol treatment. These acute metabolic interactions coupled to induction by chronic ethanol treatment may play an important role in the development of a state of oxidative stress in the liver by ethanol. 相似文献
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An original operation is proposed for localization of the diverticulum in the descending portion of the duodenum which excludes traumas of the pancreas. Clinical observations are described. 相似文献
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In-phase(IP) and out-of-phase(OP)thermal-mechanical fatigue(TMF) behavior of cast Ni-base superalloy K417 was studied.All experiments were carried out under total strain control with temperature cycling between 400-850℃.Both in-phase and out-of-phase TMF specimens exhibited cyclic hardening followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the maximum temperature.OP TMF life was longer than of IP TMF.Various damage mechanisms operating in different controlled strain ranges and phasing were discussed.A few life prediction methods for isothermal fatigue were used to handle TMF fatigue and their applicability to superalloy K417 was evaluated.The SEM analysis of the fracture surface showed that transgranular fracture was the principal cracking mode for both IP and OP TMF.Oxidation was the main damage mechanism in causing shorter fatigue life for IP TMF compared with OP TMF. 相似文献
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Three-stage treatment using a day hospital instead of a sanatorium with regards to the pattern of a tuberculosis process can achieve the results of closure of decay and abacillation cavities, which are not inferior to those with the conventional treatment, by reducing the basic regimen through the length of a hospital stage. The efficiency of two-stage treatment (day hospital--outpatient clinic) of lung tissue decay and culture-positive patients depends on the duration of the basic regimen, patient compliance, and the presence of a concomitant abnormality. 相似文献
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硅酸盐矿物和碳酸盐矿物是构成地壳的主要造岩矿物,论述了两类矿物溶解动力学的研究现状与展望,指出两类矿物的溶解和沉积过程中CO2吸收和释放,对全球环境有重要影响。 相似文献
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LW Delbridge NA Younes AI Guinea TS Reeve P Clifton-Bligh BG Robinson 《Canadian Metallurgical Quarterly》1998,168(4):153-156
Twenty-two cases of ameloblastoma and ten cases of adenomatoid odontogenic tumour (AOT) were analyzed comparatively by the AgNOR technique. Ameloblastomas were distributed into three groups according to their clinical behaviour: primary lesions without recurrences (PLWTR), 5 cases; primary lesions with recurrences (PLWR), 4 cases; and recurrences, 13 cases. The cases were also regrouped according to their histological pattern: follicular (9 cases), plexiform (7 cases), acanthomatous (4 cases) and unicystic (2 cases). Considering histological patterns, there was a significant statistical difference only between follicular and plexiform types. There were no significant differences between the group of ameloblastomas and the group of AOTs or between the three groups of ameloblastomas with different clinical behaviour. Our results strongly suggest that the distinct clinical behaviour of ameloblastomas and AOT is not correlated with their cellular proliferation ratio. Thus, the infiltrative ability of the ameloblastomas is probably not related to the cellular proliferation index of these tumours. 相似文献
20.
There is a general impression in the literature that women are more accurate reporters of familial psychiatric history. In this regard, this study presents data from a large cohort of young men (n = 427) and women (n = 607) who in answering a questionnaire self-reported alcohol abuse symptoms for various biological relatives. No significant gender differences emerged for any of the family history comparisons including reports for father, mother, either parent, any first- or second-degree relatives, or men or women relatives. The findings are discussed in the context of the existing literature. 相似文献