Influence of Nutrition on Malignant Hyperthermia in Pigs

In 2 experiments malignant hyperthermia susceptible Danish Landrace pigs were fed, for 2 or 4 weeks, synthetic diets containing casein as protein source or no protein. Minerals and vitamins were supplied to both groups. The animals were anaesthetized weekly for a maximum of 20 min with a halothane-oxygen mixture. In the first experiment malignant hyperthermia was equally delayed in both groups. If malignant hyperthermia developed, the appearance was at the end of the anaesthetic period. In the second experiment a deeper anaesthesia was employed. Malignant hyperthermia was delayed in both groups, but most markedly in the protein-deficient animals. Malignant hyperthermia developed faster after return to the original feed. These results provide evidence for a nutritional influence on the penetrance of malignant hyperthermia susceptibility during halothane anaesthesia in pigs.     

射频热疗技术在脑胶质瘤治疗中的应用进展

近几年,射频(radio frequency,RF)热疗技术以其靶向、微创、效果好,副作用少等特点,在临床治疗中,尤其是恶性肿瘤的治疗方面,取得了巨大的发展。随着研究的逐步深入,射频热疗技术越来越受到人们的重视,其应用范围也逐渐宽泛。脑胶质瘤呈广泛侵袭性生长,尤其是Ⅲ～Ⅳ级胶质瘤,具有高度间变的生长特点,术后复发快,手术加放化疗的平均生存期仅为8～11个月,严重威胁人类健康,是神经外科治疗领域中最难治疗的肿瘤。因而有关恶性脑胶质细胞瘤发生、发展及治疗的研究一直是神经外科领域的热点之一。本文就射频热疗技术的基本原理、脑胶质瘤治疗现状、射频热疗技术在脑胶质瘤治疗方面的应用,最新研究方向及进展做一综述。     

Effects of Amphetamine on Protein Synthesis and Energy Metabolism in Mouse Brain: Role of Drug-Induced Hyperthermia

Abstract: Changes in brain protein synthesis activity, and in brain levels of glucose, glycogen, and several high-energy phosphate metabolites, were evaluated under conditions of amphetamine-induced hyperthermia in mice. Protein synthesis showed a striking dependence on rectal temperature ( T _R), falling abruptly at T _R above 40°C. A similar result was obtained following direct heating of the animals. Protein synthesis activity in liver showed the same temperature dependence observed for brain. Increased synthesis of a protein with characteristics of the major mammalian stress protein, hsp 70, was demonstrated in both brain and liver following amphetamine administration. Brain protein synthesis showed significant recovery within 2 h after amphetamine administration whereas that of liver remained below 30% of control activity, suggesting significant temporal and quantitative differences in the response of individual tissues to elevated temperatures. Brain glycogen levels after amphetamine administration were significantly lower under conditions of ambient temperature which resulted in more severe drug-induced hyperthermia but did not correlate as strikingly as protein synthesis with the temperatures of individual animals. Brain glycogen also fell in animals whose temperatures were increased by brief exposure at high ambient temperature. Brain glucose levels did not consistently change with hyperthermia. Slight decreases in high-energy phosphates with increasing T _R were likely the result of fixation artifact. These results demonstrate the fundamental role of hyperthermia in the reduction of protein synthesis in brain and other tissues by amphetamine, and suggest that temperature also constitutes a significant source of variability in the effects of this drug on brain energy metabolism, in particular glycogenolysis.     

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.     

常压氧与高压氧对成年大鼠脑缺血再灌注损伤后 微血管新生影响的比较

目的:研究常压氧与高压氧对成年大鼠脑缺血再灌注损伤后微血管新生影响的差异。方法:将成年SD雄性大鼠随机分为三组:假手术组(SS组)、常压氧治疗组(NBO组)、高压氧治疗组(HBO组),每组又随机分为3、7、10天三个亚组。采用线栓法对NBO组和HBO组大鼠进行大脑中动脉栓塞(MCAO),缺血1.5小时后拔出栓子再灌注,NBO组进行常压氧治疗,HBO组进行高压氧治疗。大鼠分别在3、7、10天麻醉处死,取脑组织切片,血管内皮生长因子(VEGF)、VEGF受体-1(FLT-1)和CD34免疫组化染色,光镜观察取图和统计分析。结果:NBO各组与SS各组相比,VEGF、FLT-1和CD34阳性细胞数目均明显增多(P<0.05);HBO各组与NBO各组比较,7天、10天组VEGF、FLT-1和CD34阳性细胞数目均显著增多(P<0.05)。结论:HBO治疗较NBO治疗对成年大鼠微血管的新生更有促进作用。     

Phosphorylated Forms of Connexin43 Predominate in Rat Brain: Demonstration by Rapid Inactivation of Brain Metabolism

Abstract: The gap junction protein connexin43 (Cx43) has been reported to exist as several phosphorylated forms migrating at ˜43 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as well as an unphosphorylated 41-kDa form. In brain, Cx43 is expressed predominantly in astrocytes and is also expressed in several other cell types. Whereas the phosphorylated forms of Cx43 predominate in heart, several studies have indicated that high levels of the unphosphorylated form of Cx43 are present in brain. Various experiments in this report indicate that the 41-kDa molecular form in brain is a postmortem dephosphorylation product of phosphorylated Cx43. In rats killed by cranial high-energy microwave irradiation leading to rapid inactivation of brain metabolism, Cx43 in cerebral cortex was present almost exclusively as the 43-kDa phosphorylated form. Rapid dissection of brain followed by heat treatment or inclusion of phosphatase inhibitors during tissue homogenization also largely prevented the conversion of the 43-to the 41-kDa form. The 41-kDa species was generated after alkaline phosphatase digestion of the 43-kDa material obtained by immunoprecipitation from microwave-irradiated brain. Immunolabeling patterns and relative regional levels of Cx43 as seen by immunohistochemical and western blot detection were the same whether or not metabolism to the 41-kDa species was prevented. In developing rat brain, Cx43 levels in frontal cortex and brainstem increased with age, but the degree of dephosphorylation of the 43-to the 41-kDa form was greater at earlier ages in the brainstem. It appears that brain contains a phosphatase that may be involved in modulating the phosphorylation state of Cx43 and thus may regulate intercellular communication via astrocytic gap junctions.     

Nasal Colonization of Humans with Methicillin-Resistant Staphylococcus aureus (MRSA) CC398 with and without Exposure to Pigs

Background

Studies in several European countries and in North America revealed a frequent nasal colonization of livestock with MRSA CC398 and also in humans with direct professional exposure to colonized animals. The study presented here addresses the question of further transmission to non exposed humans.

Methods

After selecting 47 farms with colonized pigs in different regions of Germany we sampled the nares of 113 humans working daily with pigs and of their 116 non exposed family members. The same was performed in 18 veterinarians attending pig farms and in 44 of their non exposed family members. For investigating transmission beyond families we samples the nares of 462 pupils attending a secondary school in a high density pig farming area. MRSA were detected by direct culture on selective agar. The isolates were typed by means of spa-sequence typing and classification of SCCmec elements. For attribution of spa sequence types to clonal lineages as defined by multi locus sequence typing we used the BURP algorithm. Antibiotic susceptibility testing was performed by microbroth dilution assay.

Results

At the farms investigated 86% of humans exposed and only 4.3% of their family members were found to carry MRSA exhibiting spa-types corresponding to clonal complex CC398. Nasal colonization was also found in 45% of veterinarians caring for pig farms and in 9% of their non exposed family members. Multivariate analysis revealed that antibiotic usage prior to sampling beard no risk with respect to colonization. From 462 pupils only 3 were found colonized, all 3 were living on pig farms.

Conclusion

These results indicate that so far the dissemination of MRSA CC398 to non exposed humans is infrequent and probably does not reach beyond familial communities.     

异丙酚联合地氟烷麻醉对颅脑损伤患者脑保护及脑供氧平衡的影响

目的:探讨异丙酚联合地氟烷麻醉对颅脑损伤患者脑保护及脑供氧平衡的影响。方法:选取我院2018年1月至2019年1月接受手术治疗的80例颅脑损伤患者,按照双盲随机原则将入选对象分为研究组和对照组各40例,两组患者采取相同的术前麻醉诱导,术中对照组患者采取异丙酚维持麻醉,研究组患者采取异丙酚联合地氟烷维持麻醉,对比两种麻醉方案对颅脑损伤患者脑保护及脑供氧平衡的影响。结果:研究组患者苏醒时间、定力恢复时间明显短于对照组(P0.05);两组患者诱导前脑氧分压(Pbr O2)对比差异无统计学意义(P0.05),术中及术后,研究组患者PbrO2水平明显高于对照组(P0.05);术毕及术后1 h,研究组患者丙二醛(MDA)、谷氨酸(Glu)均明显低于对照组(P0.05),而血浆超氧化物歧化酶(SOD)明显高于对照组(P0.05);T0时刻,两组患者脑氧摄取率(OER)、动-静脉血氧含量差(Da-jvO2)、脑灌注压(CPP)、平均动脉压(MAP)对比无统计学差异(P0.05),T1-T3时刻,两组患者OER、Da-jvO2、CPP、MAP对比差异有统计学意义(P0.05)。结论:异丙酚联合地氟烷用于颅脑损伤患者的麻醉,具有稳定的麻醉效果,并可保护患者脑组织,维持脑供氧平衡,确保手术顺利开展,且预后效果良好。     

Rapid Inhibition of Leaf Growth by Root Cooling in Wheat: Kinetics and Mechanism

Cooling of the roots was shown here to cause marked and rapidinhibition of leaf growth in wheat seedlings, as in some otherspecies. The root-shoot signal involved in this response wasinvestigated. Displacement transducers were used for the simultaneousmonitoring of leaf growth rate and leaf thickness in individualseedlings. Leaf water status was inferred from leaf thickness.Kinetics of changing water status were compared with those ofchanging leaf growth rate in the same seedling. Leaf water statuswas found to decline markedly beginning immediately after rootcooling. This occurs because cooling reduces the hydraulic conductivityof roots almost to zero. Apparent leaf growth rate was extremelysensitive to small changes in leaf water status, and the initialdecrease in leaf water status after root cooling was sufficientto cause cessation of leaf growth. Complications arising fromleaf elasticity and other sources were considered. Prolongedroot cooling caused a sustained depression in both leaf waterstatus and leaf growth rate. The effects of root cooling onleaf thickness and growth rate were completely prevented ifwater was made freely available to the shoot. It is thereforeconcluded that hydraulic factors (signals) can explain the short-and(at least in part) the medium-term effects of root cooling onleaf growth rate in wheat. Key words: Triticum durum L., leaf growth rate, hydraulic signals, root cooling     

丙泊酚镇静对颅脑损伤患者脑氧供需平衡的影响

目的:探讨丙泊酚实施不同程度镇静对颅脑损伤患者脑氧供需平衡的影响。方法:选择急性闭合性颅脑损伤需行机械通气患者46例,随机分为轻度镇静组(A组),设定目标脑电双频谱指数(BIS)值75%;中度镇静组(B组),设定目标BIS值65%。主要观察达设定目标BIS值时丙泊酚靶控输注(TCI)浓度、Ramsay镇静评分、脑氧供需平衡指标颈内静脉血氧饱和度(SjvO_2)和脑氧摄取率(CERO_2)以及心率(HR)、平均动脉压(MAP)。结果:两组设定镇静目标需丙泊酚TCI浓度有明显差异(P0.05),但Ramsay评分比较差异无统计学意义;中度镇静组SjvO_2较基础值增加约12%(P0.05),CERO_2较基础值下降约15%(P0.05);而轻度镇静组对SjvO_2和CERO_2基础值没有影响。两组HR均较基础值减慢(P0.05),但对MAP均没有影响。结论:颅脑损伤患者维持目标镇静BIS值65%,调控丙泊酚靶浓度1.5-1.6μg/mL,更有利于改善脑氧供需平衡。     

Rapid Kinetics of Potassium-Evoked Release of Acetylcholine from Rat Brain Synaptosomes: Analysis by Rapid Superfusion

The rapid kinetics of spontaneous and evoked [3H]acetylcholine efflux from synaptosomes was investigated using the technique of rapid superfusion. Synaptosomes were isolated from whole rat brain and the intraterminal pool of acetylcholine was radiolabeled by preincubation with [3H]choline. Synaptosomes were retained within the superfusion system on filter disks and superfused with Krebs-bicarbonate buffer, pH 7.4, at flow rates of 0.3-0.5 ml/s. These experimental conditions provided a mixing half-life of 119 ms and efficiency of superfusion of greater than 85%. The kinetics of tritium efflux was followed on the second and subsecond time scales by collection of serial 4.8-s and 50-ms samples for a total of 67.2 and 1.0 s, respectively. Superfusion for 48 s with isoosmotic Krebs buffer containing 10, 20, 30, 50, 75, and 100 mM potassium ion stimulated concentration-dependent tritium release. All of potassium-evoked release, but only 17% of spontaneous release, was calcium-dependent. Kinetic analysis of net (total minus spontaneous) potassium-stimulated release revealed a single calcium-dependent component of release that fit a single exponential function with a half-life of 12.7 s. Analysis of the area under the tritium efflux curves observed on the millisecond time scale revealed that 0.111, 0.550, and 0.614% net tritium release was evoked by superfusion for 750 ms with isoosmotic buffer containing 20, 50, and 100 mM KCl, respectively. Consistent with the results observed on the second time scale, a small fraction of spontaneous release and all of potassium-evoked release observed on the millisecond time scale were calcium-dependent. These data indicate that the technique of rapid superfusion can be utilized for the direct investigation of spontaneous and evoked [3H]acetylcholine release, as well as the factors that regulate this release from brain synaptosomes on the second and millisecond time scales.     

Supravital Staining of Mammalian Brain with Intraarterial Methylene Blue Followed by Pressurized Oxygen

In 25-day-old rats, injected intraperitoneally with 0.2 ml aliquots of 6% methylene blue in saline over 1 hr followed by a single 4-6 ml intra-arterial injection; O₂ pressurized to 45 lb/in² was used to improve reblueing of 1.5-2 mm slices of cerebellum, thus increasing staining selectivity. Factors believed to influence this selectivity for axonal elements and fine dendrites are the rapidity and pressure (about 300 mm Hg) of the terminal intra-arterial injection, the hyperbaric O₂ treatment of tissue slabs for 1 hr as a substiute for room air, and immersion in 6% ammonium molybdate for 1 hr before return to atmospheric conditions.     

Exposure Time Related Oxidative Action of Hyperbaric Oxygen in Rat Brain

Hyperbaric oxygen (HBO) is known to cause oxidative stress in several organs and tissues. Due to its high rate of blood flow and oxygen consumption, the brain is one of the most sensitive organs to this effect. The present study was performed to elucidate the relation of HBO exposure time to its oxidative effects in rats’ brain cortex tissue. For this purpose, 49 rats were randomly divided into five groups. Except the control group, study groups were subjected to three atmospheres HBO for 30, 60, 90, and 120 min. Their cerebral cortex layer was taken immediately after exposure and used for analysis. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and nitrate–nitrite (NO_X) levels were determined. TBARS and SOD levels were found to increase in a time-dependent manner. GSH-Px activity reflected an inconsistent course. NO_X levels were found to be increased only in the 120 min exposed group. The results of this study suggests that HBO induced oxidative effects are strongly related with exposure time.     

经鼻高流量湿化氧疗与无创正压通气在改善AECOPD患者二氧化碳潴留临床疗效的比较

目的:经鼻高流量氧疗(HFNC)已广泛应用于缺氧性呼吸衰竭患者的治疗.本研究分析了HFNC治疗对慢性阻塞性肺疾病急性加重(AECOPD)合并Ⅱ型呼吸衰竭的治疗效果.方法:本研究前瞻性观察分析了2017年1月至2019年1月入住我院呼吸科和重症医学科,诊断为AECOPD且合并有中度Ⅱ型呼吸衰竭(血气分析PaO2/FiO2...     

经鼻高流量氧疗对阻塞性睡眠呼吸暂停综合征患者的临床疗效研究

目的:探讨经鼻高流量氧疗对阻塞性睡眠呼吸暂停综合征患者的临床疗效。方法:选择2013年7月至2017年7月我院接诊的80例急阻塞性睡眠呼吸暂停综合征患者进行研究,通过随机数表法分为观察组(n=45)和对照组(n=35)。观察组采用经鼻高流量氧疗进行治疗,对照组采用无创正压通气进行治疗,比较两组临床疗效、夜间呼吸暂停时间、呼吸暂停低通气指数(AHI)、总睡眠时间、醒觉时间、血氧饱和度、治疗前后血压、高敏C反应蛋白(hs-CRP)、低密度脂蛋白(LDL)、总胆固醇(TC)水平及生活质量评分的变化。结果:观察组患者治疗后有效率为88.89%,显著高于对照组(71.43%,P0.05)。治疗后,观察组夜间最低血氧饱和度、总睡眠时间、醒觉时间、生活质量评分均明显高于对照组,AHI、收缩压、舒张压、平均动脉压、血清hs-CRP、LDL以及TC水平均显著低于对照组(P0.05)。结论:经鼻高流量氧疗用于阻塞性睡眠呼吸暂停综合征患者的临床疗效明显优于无创正压通气进行治疗,其可显著改善患者的临床症状,提高患者的生活质量。     

Ethanol-Induced Oxygen Radical Formation and Lipid Peroxidation in Rat Brain: Effect of Chronic Alcohol Consumption

Abstract: The effect of chronic and in vitro ethanol exposure on brain oxygen radical formation and lipid peroxidation was analyzed. Ethanol induces a dose-dependent increase in lipid peroxidation in brain homogenates. The peroxidative effects of alcohol seem to be related to both cytochrome P450 and the ethanol-inducible form of cytochrome P450 (CYP2E1), because preincubation with metyrapone (an inhibitor of cytochrome P450) or with an antibody against CYP2E1 abolished the ethanol-increased lipid peroxidation. Using the formation of dichlorofluorescein, we also demonstrated that both in vitro and chronic alcohol exposure significantly enhanced the formation of oxygen radical species in synaptosomes. Chronic alcohol treatment also leads to an induction of cytochrome P450 (230%), NADPH cytochrome c reductase (180%), NADPH oxidation (184%), and CYP2E1 in brain microsomes. In addition, this treatment produced a decrease in the GSH/GSSG ratio in brain and significantly enhanced the levels of superoxide dismutase and catalase activities. This mechanism could be involved in the toxic effects of ethanol on brain and membrane alterations occurring after chronic ethanol intake.     

腹部肠管火器伤后脑组织COX-2的表达与细胞凋亡的研究

目的:探讨猪腹部肠管火器伤后脑组织环氧化酶-2(COX-2)的表达与细胞凋亡之间的关系.方法:健康长白仔猪42头随机分为对照组以及伤后1h、2h、4h、8h、12h和24h组,实验组建立腹部火器伤肠管穿透模型后,用免疫组化图像分析法测定各组脑组织COX-2的表达,采用TUNEL法观察脑细胞凋亡情况.结果:腹部肠管火器伤后COX-2在脑组织中的表达随着时间延长而表达增强、细胞凋亡率也随之增加,24小时组COX-2表达最强、细胞凋亡率最高,各实验组COX-2的表达和凋亡率明显高于对照组(P<0.01),各实验组COX-2表达与凋亡率明显高于上一时间组,具有显著性差异(P<0.05或P<0.01),Pearson直线相关分析表明,COX-2的表达与细胞凋亡率均呈正相关,相关系数为0.857(P<0.01).结论:腹部肠管火器伤后脑组织中COX-2表达与脑细胞凋亡趋势一致,且二者密切相关,提示腹部肠管火器伤后COX-2可能通过调控各种凋亡因子来促进脑细胞凋亡,从而在继发性脑损害过程中起重要作用.