肌肉高温与线粒体生物合成：TRPV1的可能作用及机制

急性暴露于热环境下运动会导致热应激,对有氧运动能力有不利影响。而长期在热环境下运动能够诱导热适应,改善有氧运动能力。热环境和运动的双重刺激会更快诱导更高的肌肉温度,温度直接或间接影响生物的各种生命活动,而过高的肌肉温度会影响骨骼肌线粒体的功能。骨骼肌线粒体功能对于有氧运动能力非常重要,线粒体生物合成的提高能改善线粒体功能。瞬时受体电位香草酸亚型1(TRPV1)是可以被高温（≥40°C）激活的蛋白,可能在肌肉高温影响线粒体生物合成中发挥作用。本文将肌肉高温、线粒体生物合成和TRPV1联系起来,探讨TRPV1在肌肉高温调节线粒体生物合成中的可能作用及机制。长期诱导肌肉高温能够促进线粒体生物合成,而急性诱导的肌肉高温会抑制线粒体生物合成,其可能机制与TRPV1、Ca2+、AMP激活的蛋白激酶（AMPK）和过氧化物酶体增殖物激活受体γ共激活因子1α (PGC-1α)等关键因子有关。TRPV1对其所在的细胞环境温度非常敏感,40℃～45℃的高温能够激活TRPV1。TRPV1被急性激活会使细胞内Ca2+水平升高,导致线粒体Ca2+过载,从而产生过量ROS不利于线粒体生物合成。TRPV1被长期激活可...     

热疗联合柔红霉素对CD34+CD38-白血病细胞增殖和凋亡的影响

目的 观察热疗联合柔红霉素(DNR)对CD34+ CD38-急性髓白血病KG1a细胞增殖的抑制作用和对其凋亡的影响.方法 免疫磁珠分离KG1a细胞中的CD34+ CD38- 细胞,以DNR作用48h后抑制50%CD34+ CD38- 细胞生长的药物浓度(IC50)作为后续实验的工作浓度.将CD34+CD38- 细胞分为对照组、热疗组(40℃、42℃)、化疗组和热化疗组(40℃、42℃).热疗、热化疗组在恒温水浴箱(40℃或42℃)hu加热60min,化疗组、热化疗组以IC50浓度的DNR处理48h.MTT法检测DNR对CD34+CD38- KG1a细胞增殖的抑制作用;流式细胞仪检测细胞凋亡率及42℃条件下细胞内DNR平均荧光强度的变化;甲基纤维素培养体系分析42℃条件下细胞的克隆形成能力.结果 KG1a细胞中分离出的CD34+CD38- 细胞纯度达95%以上,DNR的IC50为0.40μg/ml.热疗组、化疗组、热化疗组CD34+CD38-细胞增殖均明显受抑,且抑制作用随温度升高而增强(P<0.05).热疗组、化疗组及热化疗组细胞凋亡率均较对照组显著增加,且随温度升高凋亡率增加(P<0.05),热化疗组较化疗组及相同温度热疗组的细胞凋亡率显著增加(P<0.05).42℃热化疗组细胞内的DNR荧光强度(6.74±0.58)明显高于对照组(0.26±0.05)及化疗组(2.08±0.14,P<0.05).42℃热疗组、化疗组、42℃热化疗组细胞的集落形成率明显低于对照组,且42℃热化疗组明显低于42℃热疗组和化疗组(P<0.05).结论 热疗能增强DNR抑制CD34+ CD38- KG1a细胞增殖的作用,使细胞凋亡增多.     

高温对大鼠热应激蛋白的影响

在模拟高温环境下,测定大鼠热应激蛋白70kd(HSP 70)的合成,HSP70mRNA基因表达及肛温、心率、细胞形态学改变。探讨高温对HSP70的影响及HSP70在热应激中的作用。结果显示:高温使机体心率、体温升高,引起细胞损伤。三者与HSP70基因表达负相关。提示HSP70水平可成为判断机体热应激能力     

热应激对小鼠神经元骨架蛋白和热休克蛋白70表达的影响

目的观察不同温度下体外培养的小鼠皮层神经元的形态及骨架蛋白表达变化,以及与热休克蛋白70(HSP70)变化的关系。方法取小鼠胚胎大脑皮层进行神经元原代培养,7天后给予不同温度刺激,应用倒置相差显微镜观察刺激后神经元的形态变化,应用激光共聚焦扫描观察不同温度刺激后神经元中骨架蛋白(β-tubulin)、HSP70的表达变化。结果光镜观察见38℃时漂浮细胞增加,神经网络稀疏;39℃时部分细胞坏死;42℃时大部分细胞出现坏死,胞体碎裂,突起漂浮或消失。激光共聚焦扫描见高温(38~42℃)刺激后β-tubulin荧光强度低于37℃时,且温度愈高荧光强度降低愈明显;HSP70荧光强度呈钟形分布,39℃最高,37℃、42℃较低。结论热应激可以导致神经元形态变化,β-tubulin结构紊乱可能是其原因之一,HSP70也可能参与了该病理过程。     

热应激复合敌敌畏中毒对小鼠全血乙酰胆碱脂酶和组织抗氧化能力的影响

目的研究热应激复合有机磷敌敌畏（O,O-dimethyl-O-2,2-dichlorovinylphosphate,DDVP）中毒对小鼠全血乙酰胆碱酯酶活性及组织脂质过氧化的影响。方法将54只小鼠随机分为对照组、热应激组和热应激复合DDVP中毒组。实验舱相对湿度控制在（60±5）%,对照组小鼠置于24℃环境下1 h,热应激组小鼠置于38或40℃的热环境下1 h。有机磷中毒组小鼠经腹腔注射给予9或15 mg/kg DDVP,对照组给予等量生理盐水。30 min后,取全血测量乙酰胆碱酯酶（AChE）活性,取心、脑和肝组织匀浆,测量其超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量和羟自由基（.OH）抑制能力。实验期间观察小鼠一般情况,记录实验前后小鼠体质量。结果热环境（38或40℃）暴露使小鼠烦躁不安,活动量明显增加,摄水量降低,体质量减轻。与不同环境温度暴露的对照组相比,热应激复合DDVP中毒组小鼠全血AChE活性和心、脑和肝组织SOD活性和羟自由基抑制能力均明显下降（P〈0.05）,而MDA含量明显升高（P〈0.05）。热应激和DDVP中毒对上述指标的影响有交互作用。结论在本实验条件下,热应激和DDVP中毒对小鼠乙酰胆碱酯酶有显著的抑制作用,同时可引起组织脂质过氧化增强,提示氧化应激机制与高热复合DDVP中毒的加重效应有关。     

体力负荷对高温耐力的影响

本文研究了环境温度为27～50℃,相对湿度50～75%,中等强度以下体力负荷时机体生理反应特点。探讨了高温耐力与体力负荷、环境温、湿度的关系。结果表明在环境温湿度、体力负荷综合作用下,直肠温度和皮肤温度升高的幅度存在着差异,此差异决定丁机体与环境热交换的数量和性质。机体高温耐受时间随环境温湿度、体力负荷应激的增加而缩短。并将该种关系拟合了数学模型,此模型可预测环境温度40～50℃,相对湿度50～75%、中等强度以下体力负荷时机体高温耐受时间。     

热应激条件下精氨酸对胸腺的影响

近年来,精氨酸特异性免疫促进作用的研究成果令人瞩目。许多学者在对精氨酸作用机制进行探讨时,用体外培养的方法研究了精氨酸对免疫细胞功能的调节作用。因此,我们综述热应激时精氨酸对胸腺结构和免疫功能等影响的研究情况,以供同行参考。1　热应激对胸腺的影响热应激是指热环境刺激机体,激发机体温觉感受器发放神经冲动,刺激体温调节中枢,从而发生的一系列生理生化反应。在高温环境下,机体内分泌的变化是一种急性热接触的反应,尤其是在环境温度突然升高的情况下引起热应激反应时,下丘脑-垂体-肾上腺皮质系统功能增强,此时下丘脑体温调节中…     

模拟失重大鼠心肌组织HSP70表达下降

目的　研究模拟失重是否可引起大鼠心肌与血管组织HSP70的诱导表达发生改变。　方法　雄性 SD大鼠 48只随机分为两组 ,即模拟失重 4周组和对照组。模拟失重 4周后两组又各随机分为 3个小组 ,即常温组、热应激并在 2 5℃恢复 1h组和 2 h组。采用尾部悬吊大鼠模型模拟失重 4周后进行配对热应激处理。腹腔麻醉稳定后置气温 (4 3± 0 .5 )℃、湿度 2 0 %的高温舱内待结肠温度升至 42℃维持 15 m in,取出恢复室温下用 Northern杂交检测心肌和血管组织 HSP70表达的变化。　结果　热应激环境暴露后 ,各组大鼠心肌组织的 HSP70 m RNA表达均显…     

急性应激大鼠脑组织NO、SOD含量变化及意义

目的 :观察急性应激大鼠脑组织一氧化氮 (NO)含量和超氧化物歧化酶 (SOD)活力变化 ,探讨其在急性应激障碍发病中的作用。方法 :通过建立急性应激模型 ,分别取脑边缘系统大脑额叶、海马、下丘脑及中脑 ,制成脑组织匀浆测定NO的含量和SOD的活力。结果 :急性应激组大鼠大脑额叶、海马、下丘脑及中脑组织SOD活力明显高于对照组 (P <0 .0 5) ,NO含量在海马、下丘脑升高明显 (P <0 .0 5)。结论 :结果提示 ,在应激反应过程中自由基对脑有损害作用 ,可能参与应激障碍的发病。     

带呼吸囊管式背心抗荷服的热负荷测定

测定5名志愿被试者在34－35℃环境中着用带呼吸囊管式背心抗荷服时的加权平均皮肤温度（TS）、囊下局部皮肤温度、口腔温度等指标。结果表明，与不带呼吸囊组比较，管式背心加呼吸囊后除局部皮肤温度略有升高（1．2±0．1℃）外，其他各项指标均无显著差别（P＞0．05）。初步认为，在环境热负荷强度不大时，该装备不会引起飞行员显著热应激。     

Causes of interscan variability of coronary artery calcium measurements at electron-beam CT

RATIONALE AND OBJECTIVES: The authors performed this study to investigate the causes of interscan variability of coronary artery calcium measurements at electron-beam computed tomography (CT). MATERIALS AND METHODS: Two sets of electron-beam CT scans were obtained in 298 consecutive patients who underwent electron-beam CT to screen for coronary artery calcium. Interscan variations of coronary artery calcium characteristics and the effects of heart rate, electrocardiographic (ECG) triggering method, image noise, and coronary motion on interscan variability were analyzed. RESULTS: The interscan mean variabilities were 21.6% (median, 11.7%) and 17.8% (median, 10.8%) with the Agatston and volumetric score, respectively (P < .01). Variability decreased with increasing calcification score (34.6% for a score of 11-50 and 9.4% for a score of 400-1,000, P < .0001). The absolute difference in Agatston score between scans was 44.1 +/- 95.6. The correlation coefficient between the first and second sets of scans was 0.99 (P < .0001). Lower interscan variability was found in younger patients (<60 years), patients with stable heart rates (heart rate changing less than 10 beats per minute during scanning), patients with no visible coronary motion, and those with an optimal ECG triggering method (P < .05 for all). Results of multivariate logistic analysis showed that changes in calcium volume, mean attenuation, and peak attenuation were significant predictors of interscan variability and caused the interscan variations of the coronary artery calcium measurements (r2 = 0.83, P < .0001). CONCLUSION: Coronary calcification at electron-beam CT varies from scan to scan. Volumetric scoring and optimal ECG triggering should be used to reduce interscan variability. Baseline calcium score and interscan variability must be considered in the evaluation of calcium progression.     

表面修饰人工晶状体兔眼植入扫描电镜观察

目的表面修饰硅凝胶人工晶状体植入兔眼180d，对人工晶状体表面进行分析。方法术前与术后180d对人工晶状体进行扫描电镜观察。结果表面修饰技术不影响人工晶状体表面形态，修饰后人工晶状体表面的异物反应减轻。结论表面修饰提高了硅凝胶人工晶状体葡萄膜的生物相容性。     

毛发-鼻-指(趾)综合征病例分析并文献复习

目的:探讨毛发-鼻-指(趾)综合征(TRPS)的主要临床特征、骨骼X线表现及毛发超微结构特点,提高对该病的认识.方法:用刻度尺在X线片上测量患者手足长骨长度,分析患者手足骨正位片、鼻骨侧位片、脊柱正位片、骨盆正位片,以及髋关节与骶髂关节MRI图像.总结不同类型TRPS的临床特征及鉴别诊断要点.取患者头发于光镜及电镜下观...     

不育症患者精子头部及尾部超微结构的研究

目的 研究不育男性精子超微结构的形态特征。方法 利用透射电镜对8例不育男性新鲜精液标本中的精子头及尾部超微结构进行观察。结果 在电镜下不育男性精子存在多形态超微结构异常,有以下几种类型：（1）顶体异常精子,包括顶体膜受损,顶体发育不良、缺失,顶体内形成包涵体精子。（2）头部异常精子,包括其尖头精子、圆头精子、头部含空泡精子。（3）尾部异常精子：①尾部形态异常精子,包括无尾精子、短尾精子、卷尾精子、体尾胞质残余;②尾部结构异常精子,包括线粒体缺失精子、尾部线粒体多种形态和结构异常。结论不育男性精子存在顶体、头部、尾部线粒体、微管多种形态和结构异常。     

Scanning electron microscopy of intrahepatic microvasculature casts following experimental hepatic artery embolization

The initial site of occlusion of the intrahepatic microvasculature in rats following hepatic artery embolization was studied by scanning electron microscopy of microvasculature casts. The rats were divided into four groups: embolization with gelatin powder (n=3), polyvinyl alcohol (n=3, 125–150 μm), gelatin sponge (n=3, 212–250 μm), and ionized oil. Not only the hepatic arteires but also vessels in the peribiliary plexus were occluded. However, the size of the hepatic arteries and vessels of the peribiliary plexus occluded correlated with the size of the embolic material, except in the case of the gelatin powder which occluded vessels smaller than the particle size.     

Reproducibility of electron-beam CT measures of aortic valve calcification

RATIONALE AND OBJECTIVES: The authors performed this study to establish the interscan, interobserver, and intraobserver reproducibility of aortic valve calcification (AVC) measurements obtained with electron-beam computed tomography (CT). MATERIALS AND METHODS: The authors evaluated electron-beam CT scans from all patients who had undergone two serial examinations on the same day as part of a study of coronary artery calcification reproducibility. In patients in whom aortic valve calcium was identified at electron-beam CT, AVC scores were measured with both the Agatston and the volumetric methods, which were developed previously to quantify coronary calcium. RESULTS: Forty-four asymptomatic patients (mean age, 66 years +/- 9) with AVC at electron-beam CT were included in the analyses. AVC score reproducibility was excellent with both the Agatston and the volumetric methods (R2 = 0.99, P = .0001 for both), with median interscan variabilities of 7% and 6.2%, respectively. Interscan reproducibility was similar, whether the analysis included all scans or was restricted to those with scores greater than 10 or greater than 30. For the volumetric method, the median interobserver variability was 5% and the median intraobserver variability was 1%. CONCLUSION: The low interscan, interobserver, and intraobserver variabilities at electron-beam CT suggest that this method should be useful for the noninvasive monitoring of AVC changes over time and for assessing the efficacy of therapies aimed at slowing AVC accumulation.     

模拟失重状态下大鼠小肠黏膜光镜及电镜的形态学改变

目的 以尾部悬吊大鼠模型模拟失重的影响,探讨模拟失重是否可引起小肠黏膜的改变. 方法 用光学显微镜和扫描电镜,观察了对照(CON)、尾部悬吊14 d(SUS-14 d)和尾部悬吊21 d(SUS-21 d)大鼠小肠绒毛的超微结构改变. 结果 光镜下SUS-21 d组和SUS-14 d组大鼠小肠黏膜的绒毛高度降低、宽度增加、隐窝变浅,与CON组比较差异有显著性(F=294.24、60.05、328.63,P<0.05);电镜下SUS-21 d组和SUS-14 d组大鼠小肠黏膜的微绒毛高度减低、表面积缩小,微绒毛间的间距增宽,微绒毛糖衣厚度减小,与CON组比较差异有显著性(F=234.90、138.07、104.69、195.35,P<0.01). 结论 模拟失重14 d和21 d,光镜和电镜结果 均提示小肠黏膜可出现绒毛和微绒毛的变稀少,变短、变宽,表面积减小等改变.本工作还提示小肠黏膜微观结构的改变可能是造成航天员在航空飞行中出现腹泻、腹胀等消化和吸收不良症状的重要原因之一.     

紫外线对大肠杆菌的损伤机制研究

目的：观察紫外线消毒对水中大肠杆菌（E．coli）的损伤情况及其损伤机制。方法选择 E．coli ATCC 25922为实验菌,用平板计数法研究不同紫外线照射剂量下 E．coli 的灭活率及损伤情况,用拉曼光谱和透射电子显微镜分别观察紫外线消毒后该菌的膜通透性和细胞形态的变化。结果紫外线消毒后 E．coli 细胞膜通透性增加4．87倍,拉曼光谱测量显示损伤状态的该菌存在蛋白质、脂质及糖类的结构变化,透射电镜观察显示损伤状态的E．coli 质壁出现一定程度的分离。结论紫外线消毒对 E．coli 的损伤表现在蛋白质、核酸、糖类等多种生物活性分子的不同程度损伤,而不是某种结构的单一损伤。     

Measurement of the RT interval on ECG records during electron-beam CT

RATIONALE AND OBJECTIVES: The R wave of the electrocardiogram is used widely as a trigger for cardiac imaging. This study was designed to determine the optimal interval between the R wave and end systole for triggering of electron-beam computed tomography (CT) in a group of patients with various heart rates who are undergoing assessment for coronary artery calcification. MATERIALS AND METHODS: A total of 862 consecutive asymptomatic patients referred for screening with electron-beam CT for coronary artery calcification were enrolled in the study. Patients' R-R, RT, and PR intervals were measured by using the software of the CT console computer. Correlation coefficients were computed and linear regression analyses were performed for all intervals measured. Results were analyzed according to patient age (three subgroups), sex (two subgroups), and heart rate (nine subgroups). Separate formulas for calculating the length of RT intervals in men and in women were developed. RESULTS: After correction for heart rate, a significant difference was found in mean RT and PR intervals between women and men, with the mean intervals in women being longer (P < .001). No significant difference was found in these intervals within the three age-defined subgroups (< or = 40, 41-60, and >60 years; P > .05). However, significant negative correlations were found between heart rates and the lengths of all measured intervals. The results of statistical analysis indicate that most of the variation in the R-R interval with different heart rates occurred in diastole and that the duration of systole was relatively constant. CONCLUSION: For optimal cardiac imaging, triggering should take place in late systole, avoiding the RT interval variability that occurs in diastole.     

含银海藻酸盐敷料理化性质及其抗菌性能的研究

目的：探索含银海藻酸盐敷料的理化性质、生物安全性及抗菌活性。方法通过扫描电子显微镜（ SEM ）等实验方法对含银离子海藻酸盐敷料进行形貌及理化特征分析;通过MTT法,检测敷料的生物安全性;结合体外抑菌实验,研究敷料的抗菌效果。结果与海藻酸钙敷料相比,3种不同含量的银离子敷料透气率无显著差异（P＞0．05）;银离子浓度越高,其溶胀比率越高,吸水能力越强,降解越慢;MTT结果显示,细胞毒性较低;体外抑菌实验证实,银离子敷料对革兰阳性、阴性菌均具有良好的抑菌作用,同时显示银离子浓度越高,其抑菌效果越好。结论含银海藻酸盐敷料具有良好的生物相容性和抗菌活性,在创面愈合治疗中具有潜在的应用前景。