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101.
F. H. M. Mikx 《Oral microbiology and immunology》1997,12(4):249-253
The effect of pH, redox potential, O2 and H2 on the growth and proteolytic activity of Treponema denticola ATCC 33520 was studied in a chemostat at different growth rates. The peptidase and protease activities were estimated using different amido-methyl coumarin derivatives and azocasein. The maximum growth rate of T. denticola ATCC 33520 was 0.14 h−1 . Reduction of the growth rate of T. denticola by 50–60% gave: an increase in cell mass of 150–200%, a higher acetogenesis and a shift of the pH optimum. The protease and phenylalanine peptidase activities seemed to be of greater importance for the growth of T. denticola ATCC 33520 than the rather low arginine and proline peptidase activities. The redox potential (Eh ) played a secondary role. At microaerophilic conditions with 1–5% O2 , the cultures maintained a redox potential below −311 mV and an optimal acetogenesis. The presence of H? induced a marked growth stimulation of T. denticola ATCC 33520. It is concluded that the cell mass and proteolytic activity of T. denticola ATCC 33520 are modulated by the growth rate and the pH and to a lesser extend by the redox potential and presence of O2 . Stagnation of the exudate-flow influences these factors and will lead to an increase of the spirochetal population and proteolysis in the periodontal pocket. 相似文献
102.
103.
Attenuation of myocardial injury due to oxygen free radicals(OFR) by pretreatment with OFR or calcitonin gene-related peptide 总被引:3,自引:0,他引:3
目的:研究氧自由基(OFR)及降钙素基因相关肽(CGRP)预处置对OFR所致离体大鼠心脏损伤的拮抗作用.方法:Langendorf法灌流心脏,电解KH液产生OFR.结果:CGRP或OFR预处置减轻OFR所致心脏收缩功能下降,冠脉流量减少和肌酸激酶(CK)释放增加.蛋白激酶C(PKC)抑制剂H7可取消OFR预处置的心脏保护作用(对照组,OFR损伤组,OFR预处置组,H7加OFR预处置组及H7组的CK释放量分别是110±7,215±23,169±14,240±30,113±19U·L-1).结论:OFR或CGRP预处置对OFR所致心肌损伤具有拮抗作用,该作用与PKC激活有关. 相似文献
104.
PSA方式制氧是目前最先进的制氧方式,PSA制氧系统是各医院首选的供氧设备。本文阐述了PSA制氧的工作原理及购置理由,并就如何配置此系统进行了全面地论证。 相似文献
105.
In patients with peritonitis, the biological effects of oxygen aeroions reflect the interplay between molecular and cellular
effects manifesting themselves in the inhibition of lipid peroxidation, increased antioxidizing potential of blood plasma,
and decreased aggregating activity of platelets.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 9, pp. 283–285, September, 1997 相似文献
106.
红花注射液对家兔脑缺血再灌注损伤时氧自由基变化的影响 总被引:12,自引:1,他引:11
目的:探讨红花注射液对脑缺血-再灌注损伤(CIRI)的防治效应。方法:制作健康日本大耳白兔脑缺血-再灌注损伤模型,随机平均分为红花组(n=10)、缺血-再灌注组(n=10)和假手术对照组(n=10),应用黄嘌呤氧化酶法测定血浆SOD活性,用放免法测定血浆MDA浓度,并行脑组织电镜观察。结果:脑缺血再灌注期间,血浆SOD活性明显低于假手术对照组(P<0.05);血浆MDA浓度显著高于假手术对照组,尤以再灌注120min变化更显著(P<0.01);脑组织超微结构发生异常改变。使用红花注射液后,上述指标的异常变化均明显减轻,其差异有显著性。结论:氧自由基是CIRI的重要发病学因素之一,而红花注射液可能通过清除氧自由基减轻CIRI。 相似文献
107.
我们用哈白兔以3%凝固气油致25%Ⅲ°烧伤休克持续了3h复苏的动物模型研究了丹参、维生素E、抗氧化剂协同治疗烧伤休克的作用,效果显著。第5天SOD活性和MDA值均达到伤前水平,提高了动物存活时间。各项生化指标和病理证实,该组实验动物脏器无明显病变,说明联合用药,不仅可以有效的清除氧自由基,还能拮抗脂质过氧化作用,对脏器有较好的保护作用。 相似文献
108.
I. L. Kanstrup J. Marving N. Gadsbøll H. Lønborg-Jensen P. F. Høilund-Carlsen 《European journal of applied physiology》1995,72(1-2):86-94
Left ventricle systolic and diastolic functional parameters were measured by gated equilibrium radionuclide cardiography in 12 healthy men (age 33–51 years) at rest and during graded supine exercise. The leftventricle end-diastolic volume showed an initial small (11%) increase during low submaximal exercise [from mean 163 (SD 40) at rest to mean 181 (SD 48) ml], while left ventricle end-systolic volume decreased successively [from mean 59 (SD 19) to mean 39 (SD 21) ml] with increasing exercise. Stroke volume was therefore elevated at all exercise levels compared with rest [mean 104 (SD 23) ml], and the peak value [mean 128 (SD 33) ml] was found at the lowest exercise level, contributing 40% to the initial increase in cardiac output. Cardiac output increased from mean 6.2 (SD 1.4) at rest to mean 20.2 (SD 5.0) 1 · min–1 at maximum. Left ventricle peak ejection and peak filling rates increased from mean 449 (SD 89) and mean 442 (SD 85) ml · s–1 at rest to mean 996 (SD 227) and mean 1255 (SD 333) ml · s–1, respectively, at maximum. The myocardium oxygen consumption, assumed to be proportional to the sum of the stroke work and the potential energy, increased fourfold, but absolute values were twice as high as expected, indicating that extrapolation from data obtained in dog hearts (as we have done) cannot be directly applied to humans. Selected vaso-active hormones were measured at all exercise intensities. Noradrenaline (NA), adrenaline (A) and angiotensin II (AII) concentrations showed a very pronounced increase at maximal exercise compared with the preceding lower intensites, while atrial natriuretic factor (ANF) and cyclic guanosinemonophosphate (cGMP) concentrations showed a more continuous increase, and dopamine (DA) remained almost unchanged. This speaks in favour of a crucial role for NA, A and AII in preserving blood pressure at maximum exercise, while DA probably has no importance for the cardiovascular homeostasis during exercise. Increases in concentrations of ANF and cGMP were highly correlated (r = 0.86). Our data supported the opinion that there is a cardiac limitation to maximal performance connected to the cardiac pumping capacity. 相似文献
109.
采用动脉血氧饱和度仪对52例新生儿肺炎患儿,在雾化吸入治疗过程中的动脉血氧饱和度(SaO2)进行了监测,对比了吸氧与否对SaO2改变的影响。结查表明:与基础值比较,雾化吸入时患儿的SaO2显著下降(P<0.01),而雾化吸入同时吸氧者SaO2无明显变化(P>0.05),但两者比较具有显著性差异(P<0.01)。结果提示雾化吸入可使新生儿肺炎患儿SaO2下降;同时吸氧,对防止SaO2的下降有一定作用。 相似文献
110.
An investigation of the feasibility and validity of measurement of the conjunctival oxygen tension as a monitor of peripheral circulation, blood and extracellular fluid volume and cerebral circulation was carried out in 7 healthy volunteers and 5 unconscious critical care patients with proven total cerebral infarction. The healthy volunteers were subjected to changes in hydration achieved by the administration of furosemide and subsequent rehydration by administration of normal saline. Conjunctival oxygen tension was found to be a sensitive indicator of changes in the degree of hydration presumably by its ability to detect changes in peripheral circulation depending upon circulating blood and extracellular fluid volume. A drawback is that other stimuli of the sympatho-adrenergic system such as temperature and pain, interfere with measurement in the conscious volunteer. In patients with presumed total brain infarction the conjunctival PO2 cannot be used as a reliable monitor of cerebral blood flow because of varying perfusion of the palpebral conjunctiva from the external carotid artery in the occasional patient. 相似文献