次声暴露对大鼠脾、肝脏某些酶活性的影响

目的:观察8 Hz,130 dB次声暴露不同时间对大鼠脾、肝脏某些酶活性的影响.方法:35只SD大鼠随机分为5组,即对照组,1周,2周,3周,4周组.每天次声暴露1次,每次2 h.实验后,观察大鼠脾、肝脏组织中MAO,GSH-px,SOD活性和MDA含量的变化.结果:大鼠脾脏MAO活性1周,2周时显著增高(P＜0.01),3周下降,4周时又显著增加(P＜0.05).肝脏组织MAO活性变化不明显(P＞0.05).脾脏组织中GSH-px活性在4周时明显增高(P＜0.05),肝脏组织中GSH-px活性在1周时就有显著性增高(P＜0.05).脾脏SOD活性在1周至4周均有显著性增高(P＜0.05).肝脏组织在实验期变化不明显(P＞0.05).脾脏组织中MDA含量在3周至4周时有显著性增高(P＜0.05).肝脏组织在1至2周时有非常显著的增高(P＜0.01),在3周时下降,到4周时又显著高于对照组(P＜0.05).结论:8Hz,130 dB次声暴露,大鼠脾、肝脏组织活性氧自由基、脂质过氧化物增高,抗氧化能力降低,造成对组织的损伤.     

氧自由基对大鼠心肌细胞核钙转运系统的影响

观察氧自由基对心肌细胞核钙转运系统的影响。方法;大鼠心肌细胞核采用蔗糖密度梯度心分离纯化,用酶学方法测定了ＡＴＰａｓｅ活性,用＾４５Ｃａ＾２＋同位素法测定下摄取。结果;低浓度的Ｈ２Ｏ２短时间作用使核钙泵活性增加３１．６％,高浓度Ｈ２Ｏ２使核钙泵活性降低,呈时间和剂量信赖性。     

模拟65msw氦氧饱和潜水对人体氧化应激的影响

目的：探讨模拟65 msw饱和潜水暴露对机体氧化应激的影响。方法：7名健康男性潜水员参加65 msw饱和潜水,在暴露前、中、后取24 h尿检测超氧化物歧化酶（SOD）、丙二醛（MDA）、总氨基酸（T-AA）、总抗氧化能力（T-AOC）含量,同时监测24 h尿量及体重变化。结果：总氨基酸含量在减压末期比基础值显著增高,减压后1周恢复至正常水平;SOD、MDA、T-AOC在各时间点无明显变化。进舱后第1天尿量比进舱前基础值明显减少,随后逐渐恢复。加压后第2天开始体重逐渐增高,减压结束时比进舱前体重明显增高。结论：模拟65 msw饱和潜水暴露未造成参试潜水员明显氧化损伤。在饱和潜水试验中实时监测24 h尿量及氧化应激程度对防止机体损伤具有重要意义。     

氧自由基对大鼠心肌α1肾上腺素受体及其亚型的影响

采用放射配体结合方法观察外源性氧自由基对大鼠心肌α_１肾上腺素受体（α_１受体）及其亚型α_（１Ａ）与α_（１Ｂ）的影响和对β肾上腺素受体（β受体）的影响。发现：（１）·ＯＨ,使α_１受体与~（１２５）ＩＢＥ２２５４最大结合量（Ｂ_（ｍａｘ））分别下降５５％与３６％。（２）·ＯＨ可使α_１受体与~（１２５）ＩＢＥ２２５４结合的Ｋ_ｄ值增高１７１％,而对Ｋ_ｄ值无影响。（３）·ＯＨ,均使α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例增加。（４）·ＯＨ,对β受体与~（１２５）ＩＰＩＮ最大结合量Ｂ_（ｍａｘ）和Ｋ_ｄ值均无影响。（５）氧自由基清除剂甘露醇或超氧化物歧化酶均可对抗氧自由基引起α_１受体及其亚型的改变。上述结果提示,氧自由基可直接作用于心肌膜,引起α_１受体数量和亲和性下降,α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例改变。     

空气CO2增高条件下荔枝叶片光合作用和超氧自由基产率

研究结果表明,生长在77±5PaCO₂分压下30d的荔枝幼树,其光合速率较大气CO₂分压(39.3Pa)下的低23%,光下线粒体呼吸速率和不包含光下呼吸的CO₂补偿点亦略有降低.空气CO₂增高使叶片最大羧化速率(V_cmax)和最大电子传递速率(J_max)降低,表明大气增高CO₂分压下叶片的光系统I(PSI)能量水平较低,叶片超氧自由基产率亦降低39%,叶片感染荔枝霜疫霉病率则从生长在大气CO₂分压下的1.8%增至9.5%.可能较低光合和呼吸代谢诱致较低的超氧自由基产率,而使叶片易受病害侵染.叶片受病害侵染后表现为超氧自由基的激增.在全球大气CO₂分压增高趋势下须加强对荔枝霜疫霉病的控制.     

胸腺因子对老龄雄性大鼠氧自由基及抗氧化剂的作用

目的：探讨胸腺因子对老龄雄性大鼠氧自由基及抗氧化剂的作用。方法：18只21月龄老龄鼠随机分2组。一组隔日皮下注射胸腺因子D(TFD)2mg．kg^-13个月,另一老龄组和9只6月龄幼龄组作对照,注射等体积生理盐水3个月;3个月后,眼眶采血,分离血清检测。结果：老龄雄性大鼠与幼龄鼠比较,MT无变化,NO降低,LPO升高,SOD和CAT降低;TFD处理后,这种老年性改变可得到改善,并接近幼龄对照组水平;这种逆转除NO外都发生在9Am和／或8Pm。结论;胸腺因子可能对延缓衰老有益,其机制可能与胸腺-神经-内分泌-免疫-自由基网络有关。使用TFD以白天为宜。     

利多卡因对人中性粒细胞释放氧自由基的影响

目的：研究利多卡因对人中性粒细胞释放氧自由基的影响。方法：分别用５、１０、２０、５０μｇ／ｍｌ利多卡因与中性粒细胞孵育３０ｍｉｎ（３７℃）,再用趋化寡肽（ｆｍＬＰ）或佛波酯（ＰＭＡ）刺激,用化学发光法测定ｆｍＬＰ或ＰＭＡ介导的中性粒细胞化学发光反应。结果：上述各浓度的利多卡因对ｆｍＬＰ介导的中性粒细胞化学发光反应有显著的抑制作用,其抑制率分别为４７２２％、７６６３％、８４４３％、８６７２％。当用ＰＭＡ刺激时,利多卡因显著抑制其介导的中性粒细胞化学发光反应。结论：利多卡因能抑制人中性粒细胞释放氧自由基     

人工饲养鳄蜥的潜水行为及影响因素

性能是有机体完成某些生态相关任务的定量指标,自愿潜水的最长潜水持续时长是量化潜水性能的重要指标。鳄蜥（Shinisaurus crocodilurus）作为一种濒危的半水生蜥蜴,常将潜水行为作为避敌策略。2021年7至8月,人为干扰（不直接触碰）广西大桂山鳄蜥国家级自然保护区人工饲养的鳄蜥,摄像记录其相应的潜水行为,利用Pearson相关分析、单因素方差分析、一般线性模型、一元线性回归及逐步回归5种方法分析了25只亚成体、19只成体雌性、17只成体雄性共61只人工饲养鳄蜥的潜水行为及影响因素。结果表明,人工饲养鳄蜥的潜水行为具有可重复性。不同性别和年龄的人工饲养鳄蜥的最长潜水持续时长没有差异,人工饲养鳄蜥潜水时的行为不影响其最长潜水持续时长,温度也不影响人工饲养鳄蜥的最长潜水持续时长。人工饲养鳄蜥的最长潜水持续时长与尾长、尾部体积呈负相关,与尾部损失呈正相关。本研究结果表明,人工饲养鳄蜥的潜水性能受到尾部特征的影响,潜水性能和游泳性能之间可能发生了权衡。     

脾切除后自体脾组织移植的研究进展

现已证明了脾脏是人体内最大周围淋巴器官,拥有多种免疫活动性细胞因子,又是储血、滤血、造血、毁血的器官,有着重要的抗感染、抗肿瘤功能,决不能随意切除。所以正确的处理切脾与保脾、保命与保功能的关系至关重要,脾切除后自体脾组织移植进行保留脾脏功能已逐渐被认可。     

3.6MPa氦氧饱和潜水对潜水员心功能的影响

为了使我国大深度饱和潜水向纵深发展,适应未来海洋开发的需要,我所建成了500m饱和潜水设备系统,结合验收该设备的性能,进行了3.6MPa(350m)氦氧饱和潜水模拟实验的医学保障研究,心血管功能监测是实验研究的一部分。 1 材料和方法 500m(5.1MPa)饱和潜水设备系统由居住舱(17m~3)、过渡舱(8m~3)和巡潜水舱(19m~3)三部分组成。本次实验的模拟压力为3.6MPa。呼吸氦氧混合气,其中Po_2为40±2kPa,P_(N2)为90kPa,P_(co2)—     

北虫草抗氧自由基和羟自由基作用的研究

基于很多疾病与脂质过氧化有关 ,探讨了利用人工培育的北虫草的抗脂质过氧化作用。结果显示 :人工培育的北虫草子座对 Fenton反应生成的羟自由基具有较强的清除作用 ,且作用明显强于相同剂量的羟自由基特异清除剂甘露醇 (P<0 .0 1 ) ;北虫草对邻苯三酚自氧化体系产生的氧自由基亦具有清除作用 ,与对照组比较 P<0 .0 1 ,但作用弱于相同剂量的抗坏血酸。结果提示 :北虫草具有抗脂质过氧化作用。     

Modification of contractile proteins by oxygen free radicals in rat heart

This study was undertaken to investigate the effects of oxygen free radicals on myofibrillar creatine kinase activity. Isolated rat heart myofibrils were incubated with xanthine+xanthine oxidase (a superoxide anion radical-generating system) or hydrogen peroxide and assayed for creatine kinase activity. To clarify the involvement of changes in sulfhydryl groups in causing alterations in myofibrillar creatine kinase activity, 1) effects of N-ethylmaleimide (sulfhydryl groups reagent) on myofibrillar creatine kinase activity, 2) effect of oxygen free radicals on myofibrillar sulfhydryl groups content, and 3) protective effects of dithiothreitol (sulfhydryl groups-reducing agent) on the changes in myofibrillar creatine kinase activity due to oxygen free radicals were also studied. Xanthine+xanthine oxidase inhibited creatine kinase activity both in a time-and a concentration-dependent manner. Superoxide dismutase (SOD) showed a protective effect on the depression in creatine kinase activity caused by xanthine+xanthine oxidase. Hydrogen peroxide inhibited creatine kinase activity in a concentration-dependent manner; this inhibition was prevented by the addition of catalase. N-ethylmaleimide reduced creatine kinase activity in a dose-dependent manner. The content of myofibrillar sulfhydryl groups was decreased by xanthine+xanthine oxidase; this reduction was protected by SOD. Furthermore, the depression in myofibrillar creatine kinase activity by xanthine+xanthine oxidase was protected by the addition of dithiothreitol. Oxygen free radicals may inhibit myofibrillar creatine kinase activity by modifying sulfhydryl groups in the enzyme protein. The reduction of myofibrillar creatine kinase activity may lead to a disturbance of energy utilization in the heart and may contribute to cardiac dysfunction due to oxygen free radicals.     

Decrease of myocardial infarct size with desferrioxamine: possible role of oxygen free radicals in its ameliorative effect

The ability of an iron chelator, desferrioxamine, to inhibit the infarct size in in vivo rat heart was assessed. Anaesthetised rats were subjected to coronary artery ligation (CAL) for 72 hr and infarct size was measured macroscopically using TTC staining. Systolic blood pressure and ECG were monitored. Desferrioxamine (10 mg/kg and 20 mg/kg i.v.) administered half an hour after CAL markedly reduced the infarct size. However, drug treatment did not alter the systolic blood pressure of animals. In addition, desferrioxamine in vitro and in vivo demonstrated an inhibition of rat PMN-evoked and luminol-enhanced chemiluminiscence. The capacity of desferrioxamine to impair the generation or to scavenge directly oxygen free radicals may be responsible for its beneficial effect on myocardial infarct size in rats.     

活性氧、自由基与植物的衰老

介绍近 1 0年来有关活性氧、自由基的产生 ,对植物的伤害及植物对活性氧、自由基清除的研究进展。     

氧自由基清除剂的应用

对筛选和研究氧自由基清除剂的方法和模型、已知的自由清除剂、具抗氧化作用的中草药与食物及开发中的微生物来源的自由基清除剂的研究现状和最新进展作了概述。     

家蝇幼虫提取物清除氧自由基的作用

探讨了家蝇Musca domesticaL.幼虫提取物对氧自由基的清除作用。采用脱氧核糖-铁体系和邻苯三酚自氧化体系分别测定了不同浓度的提取物对羟自由基和超氧阴离子自由基的清除率,同时采用H2O2氧化体系测定了提取物的抗氧化值。结果显示家蝇幼虫提取物对羟自由基和超氧阴离子自由基的IC50分别为1.93 mg/mL和3.26 mg/mL;浓度为0.5%的提取物的抗氧化值为9.01 mg/g,为同浓度维生素C抗氧化值的1.29倍。     

The effect of weak 50 Hz magnetic fields on the number of free oxygen radicals in rat lymphocytes in vitro

The aim of the work was verification of the hypothesis that weak power frequency (50 Hz) magnetic fields (MF) affected the number of free oxygen radicals in living biological cells and that these changes could be qualitatively explained by the radical pair mechanism. The experiments were performed on rat lymphocytes. One-hour exposure to 50 Hz MF at 20, 40, or 200 microT flux densities was performed inside a pair of Helmholtz coils with axis along or crosswise to the Earth's static MF. Iron ions (FeCl2) were used as a stimulator of the oxidation processes. Oxygen radicals were measured by fluorimetry using a DCF-DA fluorescent probe. Only in the lymphocytes exposed at 40 microT MF directed along the Earth's static MF there was a decrease of fluorescence in relation to non-exposed samples. Our observation seems to confirm the hypothesis that low level power frequency MF affects oxidative processes which occur in living biological cells and that this effect can be explained by the radical pair mechanism.     

Oxygen free radicals in essential hypertension

Membrane abnormalities in essential hypertensives (EH) are well known. The respiratory burst enzyme, NADPH oxidase is located in the cell membrane of the neutrophil (PMNLs) and its activity is important in generation of oxygen derived free radical (OFR). Recently OFR have been implicated in vascular changes in variety of conditions. An attempt was made to delineate the status of OFR and antioxidants in EH. Ten, age and sex-matched, healthy controls (GpI) and 26 untreated EH (Gp IIA mild-8, Gp IIB Moderate-8, Gp IIC Severe-10) were studied. After clinical examination and basic laboratory evaluation of subjects, neutrophils isolated from their blood were studied. Chemiluminescence (CL) emitted by PMNLs after stimulation was measured (counts/min) in a luminometer and was taken as measure of OFR production and thereby of NADPH oxidase activity. The levels of antioxidants, super oxide dismutase (SOD) and reduced glutathione (GSH), were also estimated. Chemiluminescence was increased significantly (p < 0.01) in Gp IIC (243.04 ± 24.9 × 10³ counts per minute) as compared to Gp IIA (2.80 ± 1.87), Gp IIB (34.54 ± 30.24) and Gp I (0.52 ± 0.15) and SOD was reduced significantly (p < 0.05) in all EH (Gp IIA 3.9 ± 0.3 units per mg protein, Gp IIB 3.5 ± 0.3 and Gp IIC 3.12 ± 0.3) as compared to controls (4.1 ± 0.2). Similarly GSH was reduced (p < 0.05) in EH (Gp IIA 11.2 ± 1.7 mg per gm protein, Gp IIB 8.5 ± 1.1 and Gp IIC 6.6 ± 0.3) as compared to Gp I (13.5 ± 2.5). In essential hypertensives a curvilinear positive correlation was obtained between CL and both systolic (r = 0.7077, p < 0.01) and diastolic (r = 0.7965, p < 0.01) blood pressure. A significant inverse correlation (p < 0.05) was obtained between systolic and diastolic blood pressure on one hand and GSH and SOD on the other. Thus PMNLs of EH have increased emission of CL and depletion of antioxidants. The results indicate that in essential hypertension increased membrane NADPH oxidase activity is present.Abbreviations EH Essential Hypertensives - PMNLs Polymorphonuclear leucocytes - OFR Oxygen derived free radicals - Gp Group - NADPH Reduced Nicotinamide Adenine Dinucleotide Phosphate - CL Chemiluminescence - SOD Superoxide Dismutase - GSH Reduced Glutathione - SBP Systolic blood pressure - DBP Diastolic blood pressure     

心肺复苏后大鼠神经元氧自由基的变化及卡尼汀的干预作用

目的:研究心肺复苏后大鼠脑细胞氧自由基的改变及卡尼汀的干预作用。方法:本实验采用窒息合并冰氯化钾停跳液致大鼠心跳骤停5min后开始心肺复苏的动物模型,SD大鼠88只,随机分为11组:对照组(假手术组)、复苏后3、12、24、48、72h组(每组8只),复苏后卡尼汀干预3、12、24、48、72h组(每组8只)。各组抽静脉血测定血液中丙二醛(MDA)含量及超氧化物歧化酶(SOD)活力。结果:心跳骤停/心肺复苏后各组大鼠血清中MDA含量较对照组显著升高(p<0.05),SOD活力显著降低(P<0.05)。使用卡尼汀干预后,血清MDA含量显著降低(P<0.05),SOD活力基本正常(P<0.05)。结论:心肺复苏后大鼠氧自由基产生增多,清除减少;卡尼汀干预后,氧自由基产生减少。卡尼汀对心肺复苏后大鼠具有保护作用。     

模拟100 m氦氮氧常规潜水对家兔氧化应激和炎性反应的影响

目的：探讨模拟100 m氦氮氧（Trimix）常规潜水对家兔氧化应激和炎性反应的影响。方法：空白组家兔8只,模拟100 m Trimix;常规潜水组家兔8只。模拟潜水按照Haldane理论计算所得的水下阶段减压表减压。Elisa法检测家兔模拟潜水前、后血清超氧化物歧化酶（SOD）、谷胱甘肽（GSH）、过氧化氢酶（CAT）、丙二醛（MDA）和过氧化脂质（LPO）等氧化/抗氧化指标的变化。同样采用Elisa法检测空白组和潜水组家兔肺、脑组织γ干扰素（IFN-γ）、肿瘤坏死因子-α（TNF-α）、白介素6（IL-6）、白介素8（IL-8）、髓过氧化物酶活力（MPO）和基质金属蛋白酶9（MMP-9）等炎性因子的表达,并比较组织湿干比（Wet/Dry ratio）。结果：家兔潜水后SOD和GSH活性明显降低（P<0.01）,CAT、MDA和LPO含量明显升高（P<0.01）;潜水组家兔肺、脑组织中IL-8、IL-6、IFN-γ、TNF-α、MMP-9和MPO的表达均较空白组显著升高（P<0.05,P<0.01）;潜水组家兔肺、脑组织湿干比与空白组差异不显著。结论：模拟100 m Trimix常规潜水对家兔氧化应激和炎性反应有显著影响。