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1.
摘要 目的:探讨右美托咪定联合罗哌卡因腹横肌平面阻滞(TAPB)对老年腹腔镜胃癌根治术患者炎症反应、应激反应及术后谵妄的影响。方法:选择2017年7月~2019年10月期间我院接收的行腹腔镜胃癌根治术的老年患者118例,按随机信封抽签法将其分为A组(n=59,罗哌卡因TAPB麻醉)和B组(n=59,右美托咪定联合罗哌卡因TAPB麻醉),对比两组血流动力学指标、应激反应、炎症反应、术后疼痛、术后谵妄及不良反应发生率。结果:两组TAPB阻滞即刻(T1)~拔管时(T4)时间点心率(HR)、平均动脉压(MAP)均较麻醉前(T0)时间点升高(P<0.05),B组T1~T4时间点HR、MAP低于A组(P<0.05)。两组术后3 d、术后5 d皮质醇(Cor)、去甲肾上腺素(NE)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平高于术前,但术后5 d 低于术后3 d(P<0.05),B组术后3 d、术后5 d的IL-6、TNF-α、Cor、NE水平低于A组(P<0.05)。B组的术后谵妄发生率较A组降低(P<0.05),两组不良反应发生率对比无差异(P>0.05)。B组术后6 h、术后12 h、术后24 h、术后48 h视觉模拟评分法(VAS)评分低于A组(P<0.05)。结论:老年腹腔镜胃癌根治术患者采用右美托咪定联合罗哌卡因TAPB可维持血流动力学稳定,减轻应激反应、炎症反应,降低术后谵妄发生率,术后镇痛效果良好,且安全性较好。 相似文献
2.
摘要 目的:观察腹腔镜下直肠癌根治术患者应用右美托咪定复合羟考酮在术后镇痛中的作用以及对应激反应和胃肠功能恢复的影响。方法:纳入我院2018年1月~2019年12月收治的腹腔镜下直肠癌根治术患者100例,根据随机数字表法分为对照组(n=50,术后镇痛选用羟考酮)和研究组(n=50,术后镇痛选用右美托咪定复合羟考酮)。观察术后镇痛、镇静情况,分析术后不同时间点应激反应指标变化情况,观察两组术后胃肠功能恢复情况和不良反应情况。结果:两组术后不同时间点(3 h、12 h、24 h)Ramsay镇静评分、视觉模拟量表(VAS)评分随着时间的延长而降低(P<0.05)。研究组术后不同时间点(3 h、12 h、24 h)VAS评分均低于对照组,Ramsay镇静评分则高于对照组(P<0.05)。两组肠鸣音出现时间、排气时间、排便时间组间对比差异无统计学意义(P>0.05)。两组术后不同时间点(3 h、12 h、24 h)的白介素-6(IL-6)、皮质醇(Cor)、去甲肾上腺素(NE)水平先升高后降低(P<0.05)。研究组术后12 h和术后24 h的IL-6、Cor、NE水平低于对照组(P<0.05)。两组不良反应发生率组间对比无差异(P>0.05)。结论:右美托咪定复合羟考酮应用于腹腔镜下直肠癌根治术患者,可获得良好的镇静镇痛效果,同时还可减轻机体应激反应,且不影响机体胃肠功能恢复,安全有效。 相似文献
3.
摘要 目的:探讨帕瑞昔布钠和右美托咪定联合麻醉对老年腹腔镜胃癌手术患者细胞免疫功能、应激反应和认知功能的影响。方法:纳入2019年8月~2022年7月期间西安交通大学第二附属医院收治的150例老年腹腔镜胃癌手术患者。按照随机数字表法将患者分为帕瑞昔布钠组(n=50,帕瑞昔布钠)、右美托咪定组(n=50,右美托咪定)和联合组(n=50,右美托咪定联合帕瑞昔布钠)。对比三组临床指标、视觉模拟评分法(VAS)、简易精神状态检查表(MMSE)评分、术后认知功能障碍(POCD)发生率、应激反应指标[皮质醇(Cor)、肾上腺素(E)、促肾上腺皮质激素(ACTH)]、细胞免疫功能变化情况。结果:联合组的术后住院天数、肛门排气时间短于右美托咪定组、帕瑞昔布钠组(P<0.05)。联合组术后12 h、术后24 h、术后48 h VAS评分低于右美托咪定组、帕瑞昔布钠组(P<0.05)。联合组术后24 h、术后72 h MMSE评分高于右美托咪定组、帕瑞昔布钠组(P<0.05)。联合组的POCD发生率低于右美托咪定组、帕瑞昔布钠组(P<0.05)。三组术后1 d Cor、E、ACTH升高,但联合组低于帕瑞昔布钠组、右美托咪定组同期(P<0.05)。三组术后1 d CD8+升高,但联合组低于帕瑞昔布钠组、右美托咪定组同期;CD3+、CD4+、CD4+CD8+下降,但联合组高于帕瑞昔布钠组、右美托咪定组同期(P<0.05)。结论:右美托咪定联合帕瑞昔布钠应用于老年腹腔镜胃癌手术患者,镇痛效果显著,可减轻机体的应激反应、免疫抑制及对认知功能的损害。 相似文献
4.
摘要 目的:观察胃癌根治术患者在依托咪酯靶控输注联合右美托咪定麻醉下,机体细胞免疫功能、炎症因子、应激反应的影响。方法:选取2021年4月~2022年6月期间我院收治的择期行胃癌根治术患者100例,按照信封抽签的形式将患者分为对照组(n=50)和观察组(n=50),对照组患者麻醉选用依托咪酯注射液靶控输注,观察组则在对照组的基础上结合静脉输注盐酸右美托咪定注射液。观察两组患者不良反应发生情况、血流动力学指标[心率(HR)、收缩压(SBP)、舒张压(DBP)]、应激反应指标[皮质醇(Cor)、肾上腺素(E)、促肾上腺皮质激素(ACTH)]、炎症因子[肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、超敏C反应蛋白(hs-CRP)]、细胞免疫功能指标。结果:观察组用药时、拔管时SBP、HR、DBP低于对照组(P<0.05)。两组不良反应发生率组间对比无差异(P>0.05)。观察组术后1 d E、IL-6、Cor、TNF-α、ACTH、 hs-CRP、 CD8+低于对照组(P<0.05)。观察组术后1 d CD4+、CD3+、CD4+/CD8+高于对照组(P<0.05)。结论:胃癌根治术患者使用依托咪酯靶控输注联合右美托咪定麻醉,血流动力学、应激反应可得到有效控制,炎症因子、免疫功能的影响也可大大减轻,利于手术的顺利进行。 相似文献
5.
摘要 目的:探讨舒芬太尼联合右美托咪定在老年下肢骨折术后镇痛中的效果及对术后应激反应和认知功能的影响。方法:选取我院2017年4月~2021年12月期间收治的老年下肢骨折手术患者80例,根据随机数字表法分为对照组和研究组,各为40例。对照组术后镇痛予以舒芬太尼,研究组术后镇痛予以右美托咪定联合舒芬太尼,观察两组镇静镇痛效果,并观察镇痛方案对患者血流动力学、术后应激反应和认知功能的影响,记录两组不良反应情况。结果:研究组术后8 h(T1)~术后16 h(T2)时间点平均动脉压(MAP)、心率(HR)低于对照组(P<0.05)。研究组T1~术后24 h(T3)时间点视觉模拟评分法(VAS)评分低于对照组,Ramsay 镇静评分高于对照组(P<0.05)。研究组T3时间点去甲肾上腺素(NE)、肾上腺素(E) 、皮质醇(Cor)水平低于对照组(P<0.05)。研究组的术后认知功能障碍(POCD)发生率低于对照组(P<0.05)。研究组T1、T3时间点简易精神状态量表(MMSE)评分高于对照组(P<0.05)。两组的不良反应发生率对比无差异(P>0.05)。结论:右美托咪定联合舒芬太尼应用于老年下肢骨折术后患者,镇痛镇静效果确切,可减轻术后应激反应,降低POCD发生率。 相似文献
6.
摘要 目的:探讨羟考酮联合右美托咪定术后镇痛对腹腔镜下结肠癌根治术患者炎性因子、T细胞亚群和认知功能的影响。方法:选取我院于2013年1月~2019年12月期间收治的80例行腹腔镜下结肠癌根治术的患者,采用随机数字表法将患者分为A组和B组,各40例,A组给予舒芬太尼联合右美托咪定术后镇痛,B组给予羟考酮联合右美托咪定术后镇痛,对比两组围术期指标、炎性因子、T细胞亚群和认知功能。结果:B组自主呼吸恢复时间、定向力恢复时间、拔管时间短于A组,自控镇痛泵(PCA)总按压次数少于A组,PCA有效按压次数多于A组(P<0.05)。两组术前、术后1 d、术后3 d的白介素-6(IL-6)、C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)水平呈先升高后降低趋势(P<0.05),B组术后1 d、术后3 d的IL-6、CRP、TNF-α水平低于A组(P<0.05)。两组术前、术后1 d、术后3 d 的CD3+、CD4+、CD4+/CD8+呈先降低后升高趋势,CD8+呈先升高后降低趋势(P<0.05),B组术后1 d、术后3d CD3+、CD4+、CD4+/CD8+高于A组,CD8+则低于A组(P<0.05)。两组术后1 d、2 d、3 d简易精神状态检查表(MMSE)评分呈升高趋势(P<0.05),B组术后1 d、2 d、3 d的MMSE评分高于A组(P<0.05)。结论:腹腔镜下结肠癌根治术患者采用羟考酮联合右美托咪定术后镇痛,可减轻患者炎性反应及免疫抑制,同时还可减轻其认知功能损伤,促进其术后恢复。 相似文献
7.
摘要 目的:探讨右美托咪定联合舒芬太尼术后镇痛对卵巢癌根治术患者细胞免疫功能和炎症应激反应的影响。方法:根据随机数字表法将2020年2月至2023年2月期间陕西省肿瘤医院120例择期行卵巢癌根治术的患者分为对照组(n=60,术后镇痛药物选用舒芬太尼)和研究组(n=60,术后镇痛药物选用右美托咪定联合舒芬太尼)。对比两组镇静(Ramsay镇静评分)、细胞免疫功能[CD3+、CD4+、CD8+、CD4+/CD8+]、镇痛情况[视觉模拟评分法(VAS)]、不良反应、炎症应激反应[白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、皮质醇(Cor)和去甲肾上腺素(NE)]变化情况。结果:与对照组术后6 h、12 h、24 h、48 h 相比,研究组同时间点VAS评分更低,Ramsay镇静评分更高(P<0.05)。与对照组术后24 h相比,研究组同时间点CD3+、CD4+、CD4+/CD8+更高,CD8+更低(P<0.05)。两组不良反应发生率组间对比未见差异(P>0.05)。与对照组术后24 h相比,研究组同时间点IL-6、TNF-α、Cor、NE更低(P<0.05)。结论:右美托咪定联合舒芬太尼用于卵巢癌根治术患者术后镇痛,镇静、镇痛效果显著,同时还可减轻机体炎症应激反应,缓解免疫抑制。 相似文献
8.
摘要 目的:探讨腹腔镜辅助远端胃癌根治术中十二指肠优先离断对胃癌患者应激反应、炎性因子和生活质量的影响。方法:回顾性选取2018年3月~2020年12月期间河北省邯郸市中心医院收治的行腹腔镜辅助远端胃癌根治术的胃癌患者93例,根据患者手术方式的不同将患者分为对照组45例和研究组48例,对照组给予左侧后入路的腹腔镜辅助远端胃癌根治术,研究组给予十二指肠优先离断腹腔镜辅助远端胃癌根治术,比较两组围术期指标、应激反应、炎性因子、生活质量以及术后并发症情况。结果:两组清除淋巴结数量对比差异无统计学意义(P>0.05),研究组手术时间、胃肠道功能恢复时间、住院时间短于对照组,术中出血量少于对照组(P<0.05)。研究组术后3 d、术后5 d血糖、皮质醇、肾上腺素低于对照组(P<0.05)。研究组术后3 d、术后5 d白介素-6(IL-6)、C反应蛋白(CRP)、肿瘤坏死因子-?琢(TNF-?琢)低于对照组(P<0.05)。研究组术后1个月主观症状、生理功能状态、社会活动功能、心理情绪状态评分高于对照组(P<0.05)。两组术后并发症发生率对比无差异(P>0.05)。结论:与左侧后入路的腹腔镜辅助远端胃癌根治术相比,十二指肠优先离断可简化腹腔镜辅助远端胃癌根治术的手术步骤,减少胃癌患者术后应激反应和炎性反应,可有效促进患者术后恢复。 相似文献
9.
摘要 目的:探讨术前超声引导下腰方肌阻滞(QLB)联合全身麻醉对肾移植患者术后血清应激反应和疼痛相关指标的影响。方法:选择我院2019年9月~2021年8月期间收治的行肾移植手术的患者82例作为观察对象。根据随机数字表法分为A组和B组,分别为41例。A组给予全身麻醉,B组给予术前超声引导下QLB联合全身麻醉,对比两组静息视觉疼痛模拟(VAS)评分、自控静脉镇痛中的舒芬太尼使用量、有效按压次数,对比两组术后血清应激反应和疼痛相关指标变化,对比两组不良反应发生情况。结果:B组术后6 h、12 h、24 h、48 h静息VAS评分低于A组(P<0.05)。B组自控静脉镇痛中的舒芬太尼使用量少于A组,有效按压次数少于A组(P<0.05)。B组拔管后、术后24 h血糖(Glu)、皮质醇(Cor)低于A组(P<0.05)。两组术后24 h P物质(SP)、前列腺素E2(PGE2)及5-羟色胺(5-HT)均升高,但B组低于A组(P<0.05)。两组的不良反应发生率对比无差异(P<0.05)。结论:术前超声引导下QLB联合全身麻醉用于肾移植手术患者,可有效减轻疼痛和应激反应,减少自控静脉镇痛中的舒芬太尼使用量、有效按压次数,且不增加不良反应发生率。 相似文献
10.
摘要 目的:观察右美托咪定联合舒芬太尼术后镇痛对老年肺癌患者T细胞亚群、血清炎性因子和疼痛介质指标的影响。方法:选取2017年7月~2020年12月期间200例我院收治的行肺癌根治术的老年患者,按随机数字表法分为研究组(n=100)、对照组(n=100)。对照组术后镇痛选用舒芬太尼,研究组术后镇痛选用右美托咪定联合舒芬太尼,观察两组患者视觉模拟评分法(VAS)评分和Ramsay镇静评分、外周血T细胞亚群、血清炎性因子和疼痛介质指标、不良反应。结果:两组术后6 h、12 h、24 h、48 h的Ramsay镇静评分、VAS评分均较术后1 h下降(P<0.05),且研究组以上时间点Ramsay镇静评分高于对照组,而VAS评分低于对照组(P<0.05)。两组术后24 h血清干扰素-γ(IFN-γ)、白细胞介素-6(IL-6)升高,但研究组术后24 h血清IFN-γ、IL-6低于对照组(P<0.05)。两组术后24 h外周血CD8+升高,CD3+、CD4+、CD4+/CD8+降低(P<0.05),但术后24 h研究组CD8+低于对照组,CD3+、CD4+、CD4+/CD8+高于对照组(P<0.05)。术后24 h两组血清β-内啡肽(β-EP)、P物质(SP)以及一氧化氮(NO)水平均升高,但研究组低于对照组(P<0.05)。两组不良反应发生率组间对比无统计学差异(P>0.05)。结论:右美托咪定联合舒芬太尼用于老年肺癌患者术后镇痛,镇痛、镇静效果确切,同时可减轻免疫抑制及炎性反应,且安全性高。 相似文献
11.
The ATP/ADP exchange is shown to be a partial reaction of the by the absence of measurable nucleoside diphosphokinase activity and the insensitivity of the reaction to , -di(adenosine-5′) pentaphosphate, a myokinase inhibitor. The exchange demonstrates an absolute requirement for Mg2+ and is optimal at an ADP/ATP ratio of 2. The high ATP concentration () required for maximal exchange is interpreted as evidence for the involvement of a low affinity form of nucleotide site. The ATP/ADP exchange is regarded as evidence for an ADP-sensitive form of the phosphoenzyme. In native enzyme, pre-steady state kinetics show that the formation of the phosphoenzyme is partially sensitive to ADP while modification of the enzyme by pretreatment with 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) in the absence of Mg2+ results in a steady-state phosphoenzyme population, a component of which is ADP sensitive. The ATP/ADP exchange reaction can be either stimulated or inhibited by the presence of K+ as a function of pH and Mg2+. 相似文献
12.
Purified cytochrome from bovine adrenocortical mitochondria was incorporated into liposomes by the cholate-dilution method utilizing either dialysis or Sephadex gel filtration. Among synthetic phospholipids tested, dioleoylglycerophosphocholine showed the best stability during the incorporation of into liposomes. A maximum amount of heme was incorporated into liposomes at a molar ratio of phospholipid to the cytochrome of approx. 200. When was incorporated into the dioleoylglycerophosphocholine liposomes by the cholate-filtration method, the showed two major populations on the elution pattern of the Sepharose 4B gel filtration, and were seen at a diameter of 200–600 Å and its aggregated forms. When the cytochrome was incorporated into dioleoylglycerophosphocholine liposomes or cholesterol-free adrenocortical mitochondrial liposomes, was less stable than in aqueous solution. Cholesterol or adrenodoxin markedly stabilized the liposomal . Liposomal required cholesterol for its optimum reduction with adrenodoxin, adrenodoxin reductase, and NADPH in the presence of CO. About 70% of the total heme in the dioleoylglycerophosphocholine liposomes was reduced by the enzymatic reduction in the presence of cholesterol, indicating that 70% of the total molecules are exposed to the surface of the outer monolayer. In order to see the location of the heme in membrane, the dioleoylglycerophosphocholine-liposomal was subjected to treatment. This reagent destroyed the liposomal . These results suggest that the heme is located in the proximity of the reacting sites which are exposed to the surface, or located on the vincinity of polar heads of the membrane. 相似文献
13.
The partial purification of from pig lens has been achieved by treatment with deoxycholate followed by density gradient centrifugation. The specific activity of the final preparation, ranging from 300 to 500 nmol/h per mg protein, is increased approx. 100-fold compared to the homogenate. A parallel increase in activity is also observed. Sodium dodecyl sulfate (SDS) gel electrophoresis reveals six major protein bands, one of which is the 93 kDa α subunit of which can be phosphorylated by reaction with [γ-32P]ATP. A second band contains a glycoprotein which displays an apparent molecular weight of 51 000 and thus appears to be the β subunit of the enzyme. The enzyme is sensitive to ouabain with the for and inhibition being 1.2 and 1.3 μM, respectively. Several agents which inhibit from other tissues such as oligomycin, Ca2+, vanadate, , (PCMBS) and 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) also inhibit the lens enzyme. Monovalent cations other than K+ are partially effective in activating the ()-ATPase and activities. The K+ congeners were relatively more effective in supporting compared to activity. Other kinetic properties of the lens enzyme are also comparable to those of the enzyme from other tissues. Utilizing the partially purified membrane bound enzyme, discontinuities in Arrhenius plots of activity, activity and fluoresence polarization of the fluidity probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), are observed near the physiological temperature of lens. The possible significance of these observations for the mechanism of cataract formation are discussed. 相似文献
14.
Showdomycin inhibited pig brain ( with pseudo first-order kinetics. The rate of inhibition by showdomycin was examined in the presence of 16 combinations of four ligands, i.e., Na+, K+, Mg2+ and ATP, and was found to depend on the ligands added. Combinations of ligands were divided into five groups in terms of the magnitude of the rate constant; in the order of decreasing rate constants these were: (1), (2) , , and none, (3) , and , (4) and , , , and ATP. The highest rate was obtained in the presence of Na+, Mg2+ and ATP. The apparent concentrations of Na+, Mg2+ and ATP for half-maximum stimulation of inhibition () were 3 mM, 0.13 mM and 4μM, respectively. The rate was unchanged upon further increase in Na+ concentration from 140 to 1000 mM. The rates of inhibition could be explained on the basis of the enzyme forms present, including E1, E2, ES, E1-P and E2-P, i.e., E2 has higher reactivity with showdomycin than E1, while E2-P has almost the same reactivity as E1-P. We conclude that the reaction of ( proceeds via at least four kinds of enzyme form (E1, E2, E1 · nucleotide and EP), which all have different conformations. 相似文献
15.
Background
Assignment of function to new molecular sequence data is an essential step in genomics projects. The usual process involves similarity searches of a given sequence against one or more databases, an arduous process for large datasets. 相似文献16.
目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009(CA7)与A/California/4/2009(CA4)两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。 相似文献
17.
The modulating effect of membrane lipids on enzyme function has been described by several investigators. We have used the spin probe methyl stearate (M 12-NSE) to study this interaction in ox brain membranes enriched with . This methyl ester of stearic acid is practically insoluble in aqueous media, and consequently spectra of M 12-NSE-labelled preparations are free of “liquid lines”.At least two types of spectra may be obtained when ox brain microsomes are spin labelled with M 12-NSE, indicating the presence of two distinct binding sites. At one site the spin label is relatively unrestricted and gives rise to an isotropic spectrum. A second spectrum, which is obtained from spin label at another site, is similar to that which is observed after incorporation of M 12-NSE into phospholipid bilayers. This suggests that this latter site is within the core of the microsomal membrane.The two binding sites differ in their affinity for the spin probe. The low affinity site is both more abundant in crude preparations and is more easily removed by detergent treatment; spin labels at this site produce isotropic spectra. The high affinity sites are fewer in number and produce broad spectra. In addition these high affinity sites increase in concentration as the enzyme undergoes purification.The two sites are quite distinct in their sensitivity to ascorbic acid, the low affinity site showing a considerably greater rate of reduction by this agent.This study also demonstrates that the delipidation effects of sodium dodecyl sulfate and sodium deoxycholate on microsomes from ox brain are not identical.It is suggested that the two spin probe binding sites represent two different lipid domains, one of which is very closely associated with the enzyme and may reflect a protein-directed phospholipid specificity for this enzyme. 相似文献
18.
Flaviano S. Martins Aparecida A. Silva Angélica T. Vieira Flávio H. F. Barbosa Rosa M. E. Arantes Mauro M. Teixeira Jacques Robert Nicoli 《Archives of microbiology》2009,191(8):623-630
The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances,
survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation
by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast
was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice.
Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better
microorganism depending on the therapeutic or prophylactic application. 相似文献
19.
A.C. Simmonds J.M. East O.T. Jones E.K. Rooney J. McWhirter A.G. Lee 《生物化学与生物物理学报:生物膜》1982,693(2):398-406
Quenching of the fluorescence of the purified from muscle sarcoplasmic reticulum can be used to measure relative binding constants of hydrophobic compounds to the phospholipid-protein interface. We show that the binding constant for cholesterol is considerably less than that for phosphatidylcholine, so that cholesterol is effectively excluded from the phospholipid annulus around the ATPase. However, dibromocholestan-3β-ol causes quenching of the fluorescence of the ATPase, and so has access to other, non-annular sites. We suggest that these non-annular sites could be at protein/protein interfaces in ATPase oligomers. Oleic acid can bind at the phospholipid/protein interface, although its binding constant is less than that for a phosphatidylcholine, and it can also bind at the postulated non-annular sites. The effects of these compounds on the activity of the ATPase depend on the structure of the phospholipid present in the systems. 相似文献
20.
The parameters estimated from traditional A/C
i curve analysis are dependent upon some underlying assumptions that substomatal CO2 concentration (C
i) equals the chloroplast CO2 concentration (C
c) and the C
i value at which the A/C
i curve switches between Rubisco- and electron transport-limited portions of the curve (C
i-t) is set to a constant. However, the assumptions reduced the accuracy of parameter estimation significantly without taking
the influence of C
i-t value and mesophyll conductance (g
m) on parameters into account. Based on the analysis of Larix gmelinii’s A/C
i curves, it showed the C
i-t value varied significantly, ranging from 24 Pa to 72 Pa and averaging 38 Pa. t-test demonstrated there were significant differences in parameters respectively estimated from A/C
i and A/C
c curve analysis (p<0.01). Compared with the maximum ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation rate (Vcmax), the maximum electron transport rate (Jmax) and Jmax/Vcmax estimated from A/C
c curve analysis which considers the effects of g
m limit and simultaneously fits parameters with the whole A/C
c curve, mean Vcmax estimated from A/C
i curve analysis (Vcmax-C
i) was underestimated by 37.49%; mean Jmax estimated from A/C
i curve analysis (Jmax-C
i) was overestimated by 17.8% and (Jmax-C
i)/(Vcmax-C
i) was overestimated by 24.2%. However, there was a significant linear relationship between Vcmax estimated from A/C
i curve analysis and Vcmax estimated from A/C
c curve analysis, so was it Jmax (p<0.05). 相似文献