抗重组人肿瘤坏死因子单克隆抗体对内毒素血症家兔氧提取功能的影响

本工作采用渐进性低氧法降低总氧运输量,从而观察抗重组人肿瘤坏死因子（rhTNFα）单克隆抗体对内毒素血症家兔氧提取功能的影响。结果表明,在DO2－VO2的关系中,抗体保护组类同于对照组,可清楚地分为"非依赖"与"依赖"两部分;无关抗体组类同于内毒素组,从呼吸空气开始从未出现坪区。抗体保护组的临界氧运输量（DO2c）和合并氧提取率分别为10．80±3．21ml／（min·kg）和0．690,与对照组（分别为10．18±1．69和0．730）无显著差异（P＞0．05）;无关抗体组合并氧提取率为0．408,显著低于抗体保护组（P＜0.05）。在血浆中TNFα浓度,无关抗体组在各时间点上均显著高于抗体保护组（P＜0.01）。实验结果表明,精确特异性的重组人TNFα单抗具有阻断或逆转内毒素血症氧提取障碍的病理过程。     

肿瘤坏死因子介导病理性氧供应依赖性的实验研究

本研究采用抗肿瘤坏死因子单克隆抗体预先保护实验动物,用ＥＬＩＳＡ法测定血浆中肿瘤坏死因子（ＴＮＦ）浓度,藉以考察ＴＮＦ在内毒素诱导病理性氧供应依赖性（ＰＯＳＤ）模型中是否起介导作用。结果表明,（１）ＴＮＦ浓度内毒素组显著高于对照组,抗体保护组显著低于无关抗体组（Ｐ＜０．０１）。（２）在Ｖｏ＿２－Ｄｏ＿２关系中,抗体保护组可清楚地分为依赖段和非依赖段两部分,其临界氧运输量和合并氧提取率分别为１０．８０±３２１ｍｌ·ｍｉｎ￣（－１）·ｋｇ￣（－１）和０．６９０,而无关抗体组则只有依赖段,合并氧提取率为０．４０８,显著低于抗体保护组。从而证明,ＴＮＦ在内毒素所致的ＰＯＳＤ现象中起介导作用。     

肠道需氧革兰氏阴性杆菌与门静脉血内毒素水平关系的初步探讨

本实验以普通 Webster 大鼠为动物模型,探讨肠道需氧革兰氏阴性杆菌(Gram ne-gative,G~-杆菌)与门静脉血内毒素的关系。以抗生素联合灌胃使大鼠肠道脱污染,降低肠道定植抗力,再以4种需氧 G~-杆菌混合液灌胃,行肠道再污染,然后再分别测定正常鼠(组),脱污染鼠(组)及再污染鼠(组)不同肠段和粪便需氧 G~-杆菌及相应鼠门静脉血内毒素水平。结果表明,肠道需氧 G~-杆菌的变化与相应门静脉血内毒素水平的变化基本一致.由此可见,上消化道需氧 G~-杆菌过生长,可能会成为门静脉血内毒素水平增加的原因之一。     

不同低氧运动模式对大鼠免疫功能的影响

目的:探讨不同低氧运动模式对大鼠免疫功能的影响。方法:30只SD大鼠随机分为常氧运动组(对照组)、高住高练组和高住低练组,对照组大鼠每天在常氧环境下生活23 h,训练1 h;高住高练组每天在低氧环境生活23 h,训练1 h;高住低练组每天在低氧环境生活12 h,常氧环境下生活11 h,训练1 h。全血分析仪分析全血指标,流式细胞仪检测CD4~ 和CD8~ 占有的百分比。结果:与高住低练组及对照组比较,高住高练组大鼠血液红细胞计数(RBC)和血红蛋白水平(Hb)升高,CD4~ T细胞百分数降低,CD8~ T细胞百分数升高,CD4~ /CD8~ 比值下降,差异均具有统计学意义(P<0.05)。对照组大鼠、高住高练组和高住低练组ELISPOT斑点数依次为(230.0±10.6)/2×10~5个脾细胞、(56.5±6.8)/2×10~5个脾细胞和(89.3±9.8)/2×10~5个脾细胞,差异有统计学意义(P<0.05)。结论:低氧运动可以提高机体氧运输能力,但是可能会损害机体免疫功能。     

低溶氧量对怀头鲇呼吸代谢耗氧率的影响

在 ( 2 2± 1 )℃下 ,测定了怀头鲇在不同低溶氧量 (DO)时的摄氧量 (VO2 )和呼吸参数。结果表明 ,随着吸入水氧分压 (PiO2 )的降低 ,呼吸频率 (Fr)和VO2 略增 ;鳃通量 (Vg)和呼吸量 (Vb)显著增加 ;而氧利用率 (EO2 )则显著降低。在通常氧含量 ( 7 4 1mg L)时 ,怀头鲇呼吸代谢耗氧率 (Cr)仅为 2 6 3% ,但在严重缺氧 ( 2 5 8mg L)时 ,Cr 则增至 2 4 6 0 %。可见 ,低氧环境将严重抑制怀头鲇的生长。     

经皮穴位电刺激对老年髋关节置换术患者脑氧代谢以及术后认知功能、镇痛效果的影响

目的:探讨经皮穴位电刺激(TEAS)对老年髋关节置换术患者脑氧代谢以及术后认知功能、镇痛效果的影响。方法:选取2016年1月～2018年7月期间我院收治的行髋关节置换术患者91例为研究对象,将研究对象根据随机数字表法分为对照组(n=45)和研究组(n=46),对照组给予常规麻醉处理,研究组在对照组基础上给予TEAS,比较两组脑氧代谢、术后认知功能以及镇痛效果,记录两组术后的不良反应发生情况。结果:在降压开始后20 min(T1)、降压开始后40 min(T2)、停止降压后20 min(T3)时间点时,两组静脉血氧含量(Cjv O2)较降压前即刻(T0)时间点升高,且研究组高于对照组(P0.05),两组脑动-静脉血氧含量差(Da-jvO2)、脑氧摄取率(CERO2)较T0时间点降低,且研究组低于对照组(P0.05)。两组患者术后72h简易智能量表(MMSE)评分均较术前24h降低,但研究组高于对照组(P0.05),研究组术后认知功能障碍(POCD)发生率低于对照组(P0.05)。与术前比较,两组患者术后8h、术后24h、术后48h视觉疼痛模拟量表(VAS)评分均升高(P0.05),但研究组术后8h、术后24h、术后48h等时间点VAS评分均低于对照组(P0.05)。两组患者不良反应总发生率比较无差异(P0.05)。结论:TEAS对老年髋关节置换术后患者的镇痛效果确切,可有效改善脑氧代谢情况,提高术后认知功能,临床应用价值较高。     

西地那非抑制低氧肺血管内皮向平滑肌样细胞的转分化及其机制

目的探讨低氧条件下肺动脉内皮细胞(PAECs)向平滑肌样细胞的转分化及西地那非(sildenafil)对其的作用和可能机制。方法经免疫磁珠法(用血小板内皮细胞粘附分子PECAM-1做免疫分选标记)纯化分离的原代肺动脉内皮细胞,分为常氧组(含21%O2,5%CO2和74%N2)、低氧组(含1%O2,5%CO2,94%N2)、常氧 sildenafil组和低氧 sildenafil组。分别培养1d和7d。免疫荧光检测平滑肌特异性标志物α-平滑肌肌动蛋白(α-SM-actin)的表达,结合形态学鉴定平滑肌样细胞的转分化;用逆转录-聚合酶链式反应法(RT-PCR)检测myocardin mRNA的表达。结果(1)免疫荧光结果显示低氧7d组PAECs中α-SM-actin阳性率(2.07‰±0.06)(P<0.05)明显增高,阳性细胞呈梭形或多角形,而常氧组和低氧1d组均未见α-SM-actin的阳性表达;(2)RT-PCR显示myocardin mRNA的表达在低氧7d组(0.23±0.03)(P<0.05)明显增高,常氧各组和低氧1d组均未检测出其表达。(3)用sildenafil后,平滑肌样细胞的转分化率明显低于对应低氧7d组(1.02‰±0.05;P<0.05);Myocardin mRNA水平也明显降低(0.09±0.02)(P<0.05)。结论低氧可促进PAECs向平滑肌样细胞的转分化,sildenafil在一定程度上可抑制其转分化,其可能机制是通过抑制myocardin基因的表达而实现的。     

聚偏氟乙烯-丝氨酸血液灌流对感染性休克猪氧代谢的影响

目的:研究应用聚偏氟乙烯(polyvinylidene difluoride,PVDF)-丝氨酸(serine,Ser)吸附膜血液灌流对感染性休克氧代谢的影响.方法:雄性家猪16头,给予内毒素(lipopolysaccharides,LPS)1μg·kg-1·h-1静脉泵入4h复制感染性休克模型.随机分为实验组(E组),应用PVDF-Ser吸附膜进行血液灌流2h;对照组(C组),应用空白灌流器进行血液灌流2h.于基础期、注射内毒素后和血液灌流后分别测定中心静脉血氧饱和度(central venous oxygen saturation,ScvO2)、氧输送(oxygen delivery,DO2)、氧消耗(oxygen consumption,VO2)、氧摄取率(oxygen extraction ratio,O2ER)、血乳酸(lactation,LACT)和胃粘膜内pH(intramucosal pH,pHi).结果:血液灌流后E组ScvO2明显高于C组(68±1.7％vs62±3.1％,P=0.006);VO2、O2ER和LACT显著低于C组,分别为(204±28.1 mL·min-1·m-2 vs 249± 30.7 mL·min-1,m-2,p=0.017)、(33±3.3％vs 39±5.0％,P=0.031)和(3.1±1.0mmol/L vs 5.4±1.7mmol/L,P=0.022);E组的pHi较C组显著改善(7.29±0.09 vs 7.22±0.06,P=0.004).结论:应用PVDF-Ser吸附膜进行血液灌流,可以有效减少感染性休克的氧耗、纠正组织氧债和低灌注,改善机体氧代谢异常.     

大承气汤对MODS时肠道细菌微生态学影响的实验研究

目的探讨多器官功能不全综合征(MODS)大鼠肠道细菌微生态的变化及其与肠源性内毒素血症和细菌易位的关系,并观察大承气汤的影响。方法32只SD大鼠随机分成4组,对照组、模型组、大承气组和氨苄青霉素组。腹腔注射无菌酵母多糖A制备大鼠MODS模型。各组动物于造模后48 h无菌操作抽取外周静脉血和门静脉血进行内毒素含量测定;取肠系膜淋巴结进行细菌定量培养,取回肠和盲肠内容物进行肠腔内游离内毒素测定;取盲肠内容物进行肠道细菌微生态学分析。结果模型组外周血和门静脉血内毒素水平以及肠腔内游离内毒素含量均明显高于对照组(P<0.05);与对照组相比,模型组肠道菌群出现明显变化。肠球菌、肠杆菌数量明显增加,而双歧杆菌和乳酸杆菌数量出现显著下降,类杆菌数量亦出现明显下降(P<0.05)。模型组厌氧菌总数明显下降而需氧菌总数明显增加,同时厌氧菌总数/需氧菌总数的比值和B/E比值呈相应下降,发生倒置(P<0.05);正常对照组未发现肠道细菌向肠系膜淋巴结的易位,而模型组细菌易位阳性率是83.33%(P<0.05)。与模型组相比,大承气汤组上述各指标均出现明显变化(P<0.05);抗生素组作用不明显(P>0.05)。结论MODS时大鼠肠道细菌微生态出现明显变化,发生肠源性内毒素血症和细菌易位。大承气汤可以调整肠道菌群,恢复肠道微生态平衡,增加机体定植抗力,防治细菌易位和内毒素血症。     

静脉输注高氧液对单肺通气期间低氧血症的治疗作用

目的:探讨静脉输注高氧液对家猪OLV时肺内分流与氧合的影响.方法:30头健康家猪(25～35 kg)建立OLV模型后,随机分为2组,每组15头,即高氧液组(H组)和对照组(C组),H组动物在单肺通气后经右静内静脉以15 mL·kg-1·h-1的速度恒速输入高氧液,C组动物则以相同的方式和速度输入等量的乳酸林格氏液.分别于双肺通气时、单肺通气30 min、单肺通气60 min时抽取动脉血和混合静脉血做血气分析,并计算肺内分流率(Qs/Qt％),同时记录血流动力学指标.结果:与双肺通气时相比,单肺通气时两组PaO2,SaO2,PvO2和SvO2均显著降低,而Qs/Qt％明显升高(P＜0.01).单肺通气30 min以及60 min后,H组的PaO2,SaO2,PvO2和SvO2等指标均显著高于C组(P＜0.05),而对于肺内分流率(Qs/Qt％),两组间比较差异无统计学意义.结论:静脉输注高氧液虽然对肺内分流影响不大,却能够明显改善氧合,治疗单肺通气引起的低氧血症.     

Ceriometry,a combined method for chemical oxygen demand and dissolved oxygen (with a discussion on the precision of the winkler technique)

A ceriometric method is described in which Ce³⁺ salts are used for the determination of dissolved oxygen and Ce⁴⁺ salts for the determination of the chemical oxygen demand. The interference of COD in the O₂ determination, a common feature of most Winkler determinations, is corrected. The standard deviation is typically about 1% of the mean, and bias (inaccuracy) is very small.The method is simple, quick and reliable.The precision and accuracy of the Winkler method is discussed and compared with that of the Cerium method.     

暴露于高压氧时大鼠纹状体和下丘脑内L—Enk含量的变化

本研究目的在于探讨大鼠氧惊厥时,纹状体和下丘脑内亮-脑啡肽(L-Enk)含量的变化。实验中将32只雄性大鼠随机分为4组:常压空气组、高压常氧氮组、高压氧未惊厥组和高压氧惊厥组。用放射免疫法测定了纹状体和下丘脑内L-Enk含量。结果显示,在高压氧环境中暴露的大鼠纹状体和下丘脑内L-Enk含量明显高于常压空气组和高压常氧氮组;且增高到一定水平时发生惊厥。实验结果提示,动物惊厥与纹状体和下丘脑中L-Enk含量的增加呈正相关,而与高压氧环境及加减压方式无显著关系。     

Diffusion and seasonal dynamics of O2 in woody debris from the Pacific Northwest,USA

O₂ is an important regulator of physiological processes involved in the decomposition of woody debris, yet O₂ levels and diffusion rates within decomposing logs are largely unknown. We examined how O₂ diffusion rates in decayed and sound wood varied with moisture and density, and we compared predicted with observed seasonal changes in oxygen concentration in logs in a Pacific Northwest old-growth Pseudotsuga menziesii forest. In the laboratory, the oxygen diffusion coefficient (D_O2) was determined in the longitudinal and radial (or tangential) directions on wood cores of varying moisture content and density. In the field, O₂ was measured in tubes inserted to three radial depths (2, 6 and 15 cm) within logs of two species (Pseudotsuga menziesii and Tsuga heterophylla) and five decay classes (where class 5 = most decayed). In both the radial and longitudinal directions, D_O2 increased exponentially as the air filled pore space (AFPS) increased and as density decreased. In the field, mean O₂ concentrations in logs were not significantly different between species. Mean O₂ concentrations were significantly lower in the least decayed logs as compared to the most decayed logs. Mean O₂ concentrations decreased with radial depth only in decay class two logs. Seasonal O₂ levels did not consistently vary with log moisture, respiration, or air temperature. The comparison of the results from a model that assumes oxygen diffuses only in the radial direction to field data indicates that laboratory measurements of oxygen diffusion may underestimate field oxygen concentrations. Cracks, insect galleries and other passages in decayed logs, and longitudinal oxygen diffusion may account for this discrepancy. In the field, log oxygen concentrations were rarely as low as 2%, indicating anaerobic conditions may not be as common in logs as we previously thought. Oxygen limitations on decomposition may occur in relatively sound and/or water soaked wood, but probably not in decayed logs in a terrestrial setting.     

Ecophysiological mechanisms of plant growth under the influence of rhizosphere oxygen concentration: A review

Oxygen is an essential substance for plants, and adequate oxygen supply is necessary for plant growth and developments. As one of the major abiotic threats to plants, frequent floods could lead to oxygen deficiency in the rhizosphere. Therefore, it is important to understand the response and adaptive mechanisms of plants to rhizosphere oxygen concentration for crop productions and breeding of resistant varieties. This review shed light on the impacts of rhizosphere oxygen contents on plants from multiple perspectives. We also demonstrated the injury and acclimations caused by oxygen deficiency and the mechanism of low-oxygen signaling. We finally summarized methods to avoid oxygen deficit and prospect of further studies.     

Continuous, real-time monitoring of the oxygen uptake rate (OUR) in animal cell bioreactors

A new method for real-time monitoring of the oxygen uptake rate (OUR) in bioreactors, based on dissolved oxygen (DO) measurement at two points, has been developed and tested extensively. The method has several distinct advantages over known techniques.It enables the continuous and undisturbed monitoring of OUR, which is conventionally impossible without gas analyzers. The technique does not require knowledge of k(L)a. It provides smooth, robust, and reliable signal. The monitoring scheme is applicable to both microbial and mammalian cell bioprocesses of laboratory or industrial scale. The method was successfully used in the cultivation of NSO-derived murine myeloma cell line producing monoclonal antibody. It was found that while the OUR increased with the cell density, the specific OUR decreased to approximately one-half at cell concentrations of 16 x 10(6) cells/mL, indicating gradual reduction of cell respiration activity. Apart from the laboratory scale cultivation, the method was applied to industrial scale perfusion culture, as well as to processes using other cell lines. (c) 1994 John Wiley & Sons, Inc.     

A new method to measure the haemoglobin oxygen saturation by the oxygen electrode

We describe a new polarographic method to measure the haemoglobin oxygen saturation in whole blood, employing up to 10 μl of sample in a standard case. The measurement is done in an anaerobic staineless-steel cuvette (1 ml) recording three oxygen tension values: (1) that of an air-equilibrated buffer before the addition of the sample; (ii) that after the addition of the sample; and (iii) that after the addition of an oxidant. The haemoglobin oxygen saturation is then calculated from the three oxygen tension values, the volume of the reagents, and solubility coefficient of oxygen. This method is simple, inexpensive and accurate, and correlates well with other standard methods.     

Oxygen transfer characteristics of miniaturized bioreactor systems

Since their introduction in 2001 miniaturized bioreactor systems have made great advances in function and performance. In this article the dissolved oxygen (DO) transfer performance of submilliliter microbioreactors, and 1–10 mL minibioreactors was examined. Microbioreactors have reached k_La values of 460 h^?1, and are offering instrumentation and some functionality comparable to production systems, but at high throughput screening volumes. Minibioreactors, aside from one 1,440 h^?1 k_La system, have not offered as high rates of DO transfer, but have demonstrated superior integration with automated fluid handling systems. Microbioreactors have been typically limited to studies with E. coli, while minibioreactors have offered greater versatility in this regard. Further, mathematical relationships confirming the applicability of k_La measurements across all scales have been derived, and alternatives to fluorescence lifetime DO sensors have been evaluated. Finally, the influence on reactor performance of oxygen uptake rate (OUR), and the possibility of its real‐time measurement have been explored. Biotechnol. Bioeng. 2013; 110: 1005–1019. © 2012 Wiley Periodicals, Inc.     

Activation of Molecular Oxygen by Infrared Laser Radiation in Pigment-Free Aerobic Systems

With the goal of mimicking the mechanisms of the biological effects of low energy laser irradiation, we have shown that infrared low intensity laser radiation causes oxygenation of the chemical traps of singlet oxygen dissolved in organic media and water saturated by air at normal atmospheric pressure. The photooxygenation rate was directly proportional to the oxygen concentration and strongly inhibited by the singlet oxygen quenchers. The maximum of the photooxygenation action spectrum coincided with the maximum of the oxygen absorption band at 1270 nm. The data provide unambiguous evidence that photooxygenation is determined by the reactive singlet ¹_g state formed as a result of direct laser excitation of molecular oxygen. Hence, activation of oxygen caused by its direct photoexcitation may occur in natural systems.     

Tunable Internal and Surface Structures of the Bifunctional Oxygen Perovskite Catalysts

Perovskite oxide ceramics attracts significant attention as a strong candidate of bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalyst for the metal‐air batteries. Numerous approaches to the viability of bifunctional perovskite electrocatalyst represent that the electro­chemical performance is highly correlated with defect chemistry, surface structure, and overall polycrystalline perovskite structure. By making use of the intrinsic flexibility of internal structure and high nonstoichiometry in perovskite oxide, the heat treatment effect of the complex Ba_0.5Sr_0.5Co_xFe_1‐xO_3‐δ (x = 0.2 and 0.8) perovskites in argon atmosphere at 950 °C (Ar‐BSCF5582 and Ar‐BSCF5528) on the surface structure/defect chemistry and electrocatalytic performance is intensively investigated. Upon heat‐treatment in argon atmosphere, the amorphous thickness layer increases from ≈20 to 180–200 nm in BSCF5582, while there is little change in BSCF5528 with ≈20 nm. The electrocatalytic performance of BSCF5582 catalyst both in ORR and OER deteriorates seriously, while Ar‐BSCF5528 demonstrates a significant increase of electro­chemical performance in ORR. This study demonstrates that the electrochemical performances of a perovskite catalyst can be significantly determined by the simultaneous modification of both surface structure and internal defect chemistry, which are explained with transmission electron microscopy and atomic‐selective X‐ray absorption fine structure analyses, respectively.