不同压力的PEEP和CPAP在电视辅助胸腔镜手术下行单肺通气时对氧合作用及分流的影响

目的评价呼气末正压通气(PEEP)和连续气道正压通气(CPAP)在电视辅助胸腔镜手术(VATS)行单肺通气麻醉时对患者血氧合作用的影响.方法选择30例在VATS下行肺叶切除的单纯肺癌患者,随机分为A、B两组.A组于手术开始后15 min(A1)、单肺通气后15 min(A2)、术肺0 CPAP健肺5 cm H2O PEEP后15 min(A3)、术肺5 cm H2O CPAP健肺0 PEEP后15 min(A4)、术肺5 cm H2O CPAP健肺5 cm H2O PEEP后15 min(A5)分别监测平均肺动脉压(PAP)、平均动脉压(MAP)、心率(HR)、动脉血氧分压(PaO2)、动脉血氧饱和度(SaO2)、混和静脉血氧饱和度(SvO2)并计算分流(Qs/Qt)值.B组用10 cm H2O PEEP和10 cm H2O CPAP重复上述过程.结果A组间PAP、MAP、HR、PvO2、SaO2以及SvO2无显著性差异(P＞0.05);与A2(PaO2119.5±28.7,Qs/Qt35.7±6.3)时相比,A3时的PaO2(200.8±30.6)显著增加,Qs/Qt值(23.8土6.5)显著降低;A4时的PaO2(221.4±16.6)显著增加,Qs/Qt值(24.8±5.9)显著降低;A5时的PaO2(240.2±46.3)显著增加,Qs/Qt值(23.5±6.4)显著降低(P＜0.05),A3,A4,A5间相比较无显著差异(P＞0.05).B组间PAP、MAP、HR、PvO2、SaO2以及SvO2无显著性差异(P＞0.05);与B2相比,B3、B4、B5 PaO2显著增加、Qs/Qt值显著降低(P＜0.05).但与A组相比无显著差异(P＞0.05).结论在VATS行单肺通气麻醉时,健肺使用PEEP、患肺使用CPAP或联合使用PEEP和CPAP能提高患者手术中的氧合作用,降低Qs/Qt值;与5 cm H2O PEEP和CPAP比较,10 cm H2O PEEP和CPAP不能进一步改善PaO2和Qs/Qt.     

不同对比剂对双源CT冠状动脉成像中患者心率的影响

目的 探究双源CT冠状动脉成像中,静脉注射碘克沙醇320与碘普罗胺370对比剂对患者心率的影响.方法 回顾性搜集行冠状动脉CTA检查的389例患者的病例资料,根据注射对比剂不同分为2组,A组采用碘克沙醇320,B组采用碘普罗胺370,记录CT增强扫描前屏气状态下心率(基础心率)、扫描过程中注射对比剂时屏气状态下心率(注射时心率).基础心率<75次/min时,舌下含服硝酸甘油0.25 mg.比较所有患者注射对比剂前后的心率变化并对2组患者的心率变化进行比较.结果 注射对比剂后心率变化>10次/min的患者A组有8例(4.4%),B组有10例(4.8%),2组无统计学差异(P>0.05).经静脉内注射对比剂时,2种对比剂均使患者心率减低(碘克沙醇下降4.2次/min、碘普罗胺下降2.7次/min,P>0.05),服用硝酸甘油均减轻对比剂对心率的影响.结论 经静脉注射碘克沙醇320与碘普罗胺370后,均约有4%的患者心率变化>10次/min,2种对比剂对心率的影响是一致的.     

Comparison of the correlations between impact loading rates and peak accelerations measured at two different body sites: Intra- and inter-subject analysis

BackgroundHigh average (VALR) and instantaneous vertical loading rates (VILR) during impact have been associated with many running-related injuries. Peak acceleration (PA), measured with an accelerometer, has provided an alternative method to estimate impact loading during outdoor running. This study sought to compare both intra- and inter-subject correlations between vertical loading rates and PA measured at two body sites during running.MethodsGround reaction force data were collected from 10 healthy adults (age = 23.6 ± 3.8 years) during treadmill running at different speeds and inclination surfaces. Concurrently, PAs at the lateral malleoli and the distal tibia were measured using synchronized accelerometers.ResultsWe found significant positive intra-subject correlation between loading rates and PA at the lateral malleoli (r = 0.561–0.950, p < 0.001) and the distal tibia (r = 0.486–0.913, p < 0.001). PA measured at the lateral malleoli showed stronger correlation with loading rates (p = 0.004) than the measurement at the distal tibia. On the other hand, inter-subject variances were observed in the association between PA and vertical loading rates. The inter-subject variances at the distal tibia were 3.88 ± 3.09 BW/s and 5.69 ± 3.05 BW/s in VALR and VLIR respectively. Similarly, the inter-subject variances in the measurement at lateral malleoli were 5.24 ± 2.85 BW/s and 6.67 ± 2.83 BW/s in VALR and VLIR respectively.ConclusionsPA measured at lateral malleoli has stronger correlation with VALR or VILR than the measurement at distal tibia. Caution is advised when using PA to conduct inter-subject comparisons of vertical loading rates during running.     

Comparison of three physiologically-based pharmacokinetic models for the prediction of contrast agent distribution measured by dynamic MR imaging

PURPOSE: To compare the performance of three physiologically-based pharmacokinetic (PBPK) models for predicting gadolinium contrast agent concentration-time curves (Gd-CTCs) obtained in superior sagittal sinus (SSS), cerebral cortex, and psoas muscle. MATERIALS AND METHODS: Three published whole-body PBPK models were modified to predict Gd-CTCs in normal-appearing tissue. The models differed in the number of organs modeled and total number of compartments, and were designated as the "well-mixed," "delay," and "dispersion" models. The suitability of the three models to predict Gd-CTC was studied using data from dynamic contrast-enhanced MR perfusion imaging obtained at 1.5T from 10 patients with glioblastoma multiforme and at 3.0T from five patients with liver metastases. RESULTS: The dispersion model produced better fits than the delay model in the SSS (P < 0.0001) and cerebral cortex (P < 0.0001), and better fits than the well-mixed model in psoas muscle (P < 0.005). No model produced better fits than the dispersion model at any of the three locations. CONCLUSION: In this evaluation, the dispersion model was most robust for prediction of Gd-CTCs derived from dynamic contrast-enhanced (DCE)-MRI. This represents a preliminary step in the development of a PBPK model useful for predicting Gd-CTCs at a time resolution appropriate for dynamic MRI applications.     

Muscle excitability during sustained maximal voluntary contractions by a separate analysis of the M‐wave phases

This study was designed to examine separately the changes in the first and second phases of the muscle compound action potential (M‐wave) during and after a sustained 3‐minutes maximal voluntary contraction (MVC). M‐waves were evoked by supramaximal single shocks to the femoral nerve given at 10‐seconds intervals throughout a sustained isometric 3‐minutes MVC and also during six brief MVCs performed throughout a 30‐minutes recovery period. The amplitude, duration, and area of the M‐wave first and second phases, together with muscle conduction velocity and force, were measured. During the 3‐minutes MVC, the amplitude of the first phase increased progressively for the first minute (33%‐43%, P<.01) and remained stable thereafter, whereas the second phase initially increased for 25‐35 seconds (30%‐50%, P<.01), but subsequently decreased significantly before stabilizing. During the recovery period, the amplitude of the M‐wave first phase showed a decreasing trend, returning to pre‐fatigue values (P>.01) within 5‐10 minutes, while the second phase increased progressively and remained higher than control (7%‐20%, P<.01) after the 30‐minutes recovery time. Maximal cross‐correlations between the time course of the first phase amplitude and those of conduction velocity and force (0.9‐0.93) occurred for a lag of 0 seconds, whereas maximal cross‐correlations corresponding to the second‐phase amplitude (0.6‐0.7) occurred for a 50‐seconds time lag. The present findings indicate that the potentiation of the first phase results from impaired muscle membrane excitability. The peak‐to‐peak amplitude and second‐phase amplitude are not valid indicators of muscle excitability as they might be critically affected by muscle architectural features.     

Sagittal plane translation of the knee during stair walking in healthy volunteers measured by an electrogoniometer chain

Maximal sagittal plane knee translation during stair walking was investigated in 5 healthy male subjects without any previous history of knee joint trauma during 2 types of ascents and descents (straight and side) using an electrogoniometer system (CA-4000, OS Inc., Hayward CA, USA). During the ascents, the tibia moved anteriorly in relation to femur, whereas during the descents it moved posteriorly. The maximum translations occurred within the range of 39° to 51° of knee flexion and were significantly larger during the ascents than during descents, but there was no difference between straight and side activities. There were significant interindividual differences in the maximum translations during the ascent or descent cycles but no differences between trials or the right or left limbs. The mean difference between repeated trials was 1.2 mm and the 95% confidence interval was ±0.6 mm.     

两种不同溶液体系提取大鼠脊髓蛋白双向电泳图谱比较

目的：比较尿素／CHAPS和尿素／硫脲／CHAPS／SB3－10两种不同溶液体系提取大鼠脊髓蛋白双电泳（two-dimensional electrophoresis,2-DE)图谱的差异。方法：大鼠脊髓经三氯醋酸／丙酮沉淀粉蛋白后,分别用尿素／CHAPS和尿素／硫脲／CHAPS／SB3－10两种不同的溶液体系提取蛋白。以固相PH梯度（IPG）等电聚焦为第一向,SDS－PAGE水平电泳为第二向进行蛋白质2－DE。图像分析软件ImageMaster 2D Elite3.01分析蛋白质2－DE图谱。结果：两种蛋白提取溶液分别获得1059和1023个蛋白（亚基）斑点,其中790个蛋白在两张图谱中重叠,其余269和233个蛋白点为两种体系各自所特有。两种提取方法共获得1292个蛋白斑点。结论：综合使用不同蛋白提取方法有助于提高组织蛋白2－DE图谱的完整性。     

蒙特卡罗N粒子运输法计算与实际测量的60 Co治疗机剂量分布比较

目的 探讨蒙特卡罗N粒子运输法(MCNP)模拟计算的可行性.方法 用百分深度剂量(PDD)分布及标准峰值散射因子(NPSP),比较水模体计算值和实际测量及报告值之间的差异.结果 在10 cm×10 cm射野时,测量值和计算值之间差异无统计学意义(t=-0.41,P>0.05),而在5 cm×5 cm及12 cm×12 cm时,测量值与计算值之间差异有统计学意义(t=7.2、-4.6,P<0.05).计算值和报告值之间符合良好,差异无统计学意义(t=-1.906,P>0.05).同一射野最大剂量点下百分深度剂量随深度增大而减少,同一深度处百分深度剂量随射野增大而增大;同一深度处射野中心轴上的剂量最高,向射野边缘剂量逐渐减少.结论 利用蒙特卡罗MCNP可以建立一组准确和全面的百分深度剂量及标准峰值散射因子参数,为放疗质量保证和质量控制提供依据.

Abstract：

Objective To discuss the feasibility of Monte Carlo N-particle transport code(MCNP)simulated calculation.Methods The calculation in water phantom was contrasted with the practical measurements and the reported values using the percent depth dose(PDD)curve and normal peak scatter factor.Results There Was no significant difference between calculated and measured results in the 10 cm×10 cm field(t＝-0.41,P>0.05),however,there were significant differences in the 5 cm×5 cm field(t=7.2,P<0.05)and in the 12 cm×12 cm field(t=-4.6,P<0.05).There was no significant difierence between the calculated results and the reported values(t=-1.91,P>0.05).In the same radiation field,the PDD decreased as the depth increased,but increased as the size of the radiation field increased at the same depth.PDD and normal peak scatter factor were both important parameters for calculation of prescribed dose.Conclusions It is possible to establish a set of accurate and comprehensive percent depth doses and normal peak scatter factor parameters so as to provide the basis of clinical use, quality assurance and quality control for radiotherapy.     

Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P‐MRS

To investigate the high‐energy phosphate metabolism by ³¹P‐nuclear magnetic resonance spectroscopy during off‐transition of exercise in different muscle groups, such as calf muscles and biceps femoris muscles, seven male long‐distance runners (LDR) and nine untrained males (UT) performed both submaximal constant and incremental exercises. The relative exercise intensity was set at 60% of the maximal work rate (60%Wmax) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate (P_i) and phosphocreatine (PCr) peaks were determined. During the 5‐min recovery following the 60%Wmax, the time constant for the PCr off‐kinetics was significantly faster in the plantar flexion (LDR: 17.3 ± 3.6 s, UT: 26.7 ± 6.7 s) than in the knee flexion (LDR: 29.7 ± 4.7 s, UT: 42.7 ± 2.8 s, P < 0.05). In addition, a significantly faster PCr off‐kinetics was observed in LDR than in UT for both exercises. The ratio of P_i to PCr (P_i/PCr) during exercise was significantly lower during the plantar flexion than during the knee flexion (P < 0.01). These findings indicated that the calf muscles had relatively higher potential for oxidative capacity than that of biceps femoris muscles with an association of training status.     

肌肉注射灭活SARS病毒早期对BALB/c小鼠黏膜部位淋巴细胞表型的影响

目的了解灭活SARS病毒肌肉途径注射小鼠后早期对小鼠黏膜免疫系统的影响.方法将5周龄的雌性BALB/c小鼠随机分为两组,每组5只,实验组每只小鼠经肌肉注射溶于100μl PBS中的50μg纯化的灭活SARS病毒,对照组注射等量的PBS,3d后处死小鼠,用流式细胞仪测定不同黏膜组织中淋巴细胞表型的变化.结果肌肉注射灭活SARS病毒使鼻黏膜相关淋巴组织(NALT)中CD+4荧光强度显著增加(P<0.05)、CD+3荧光强度有增加趋势(P=0.052);鼻通道(NP)淋巴细胞中CD+4和CD+8构成比显著增加(P<0.05)、CD+3构成比和T/B比值有增加趋势,而CD+4,CD+3和B细胞荧光强度都有显著增加(P<0.05);肺CD+8构成比显著降低(P<0.05)、B细胞构成比显著增加(P<0.01)、CD+4构成比有降低趋势(P=0.238)、T/B比值有降低趋势(P=0.077)、CD+4/CD+8比值有增加趋势,而CD+3荧光强度显著增加(P<0.05)、CD+4荧光强度有增加趋势(P＝0.086);小肠派氏集合淋巴结(PP)中B细胞构成比显著增加(P<0.05).结论肌肉注射SARS灭活病毒早期,可以使多部位黏膜淋巴组织的淋巴细胞表型发生变化,显示其可能诱导机体产生黏膜免疫应答.