受孕龄28～30周早产儿脑电图高幅慢波改变对其预后的评估价值及临床意义

目的 观察受孕龄(conceptional age,CA) 28～ 30周早产儿脑电图高幅慢波改变情况,探讨其对早产儿预后的评估价值及临床意义.方法 2011年8月至2012年5月我院新生儿重症监护病房收治受孕龄28～30周早产儿34例,于生后1～3d进行床旁视频脑电图(video electroencephalogram,VEEG)监测,根据受孕龄将受监测者分为受孕龄28～ 29周及30周2个观察组,根据随访结果又将2个观察组细分为死亡组和存活组,各12例,对每份VEEG记录的暴发间隔时间(interburst interval duration,IBI)及高幅慢波进行20 min半定量分析.结果 死亡组与存活组比较,最大IBI时程在受孕龄28 ～ 29周及30周均差异显著(P＜0.01)；高幅慢波主要分布于颞、枕区,形态以光滑δ波占优势,其次为δ刷,波幅以150～300 μV为主,在该波幅段优势空间分布及优势波形分布无差异,＞300 μV慢波在死亡组中数量高于存活组,在空间分布上于颞、枕及前额区有差异(P＜0.05),在形态上重叠多高尖波的δ波分布差异最为显著(P＜0.01),其次为尖样δ波和δ刷(P＜0.05)；畸形δ刷、畸形δ波中重叠多高尖波的δ波和一般畸形δ波在死亡组中的发生率均高于存活组(P＜0.05).结论 早产儿早期床旁VEEG中IBI时程过长及特殊形态的畸形高幅慢波过多提示脑损伤和/或预后不良发生可能.     

Respiratory Variations in Arterial Blood Pressure and Heart Rate in Normotensive and Renal Hypertensive Dogs

Respiratory sinus arrhythmia (RSA), systolic and diastolic respiratory blood pressure waves (RBPWsyst, RBPWdiast), mean heart rate (HR), mean respiratory frequency (RF) and the heart beat to respiratory cycle ratio (HB/RC) were measured in 23 spontaneously breathing, normotensive or renal hypertensive dogs under light anaesthesia. No significant differences were found between conditions of normal and chronically elevated blood pressure. All these parameters were analyzed statistically by means of linear regression analysis and rank correlation coefficient (rs). A correlation was found to exist between RSA and mean systolic blood pressure (negative), RF (negative), RBPWsyst (positive), RBPWdiast (positive). RF correlated with both HB/RC (negative) and RBPWsyst (negative). A correlation was also seen between PA and both BPsyst (positive) and BPdiast (positive), BPsyst and BPdiast (positive) and between HR and RBPWdiast (negative); however, all the remaining, theoretically possible correlations were not significant. The results may be referred to resonance mechanisms in a common nervous oscillator system.     

On the mechanism of colonic motility: the electric activation theory of colonic contraction

PURPOSE: A previous study has demonstrated that the longitudinal muscle possesses electric activity, while the circular does not (A. Shafik and A. A. Shafik, 2000, Front. Biosci. 5, b5). In the current study, we investigated the mechanism of action of the two colonic muscle coats in the motility of the gut. METHODS: Fourteen patients (43.8 years, 10 men) with left colon or rectal cancer were scheduled to have transverse colostomy as a part of their operation. The electric activity of the ascending colon was recorded by three electrodes applied to each of the circular and the longitudinal (taenia coli) muscle coats. Simultaneously, the colonic pressure was recorded before and after colonic distension. The test was repeated after longitudinal muscle anesthetization. RESULTS: Electric waves in the form of pacesetter (PPs) and action (APs) potentials were recorded from the longitudinal but not the circular muscle fibers. APs were associated with an intracolonic pressure rise. Colonic distension produced significant increase in the PPs and APs recorded from the longitudinal muscle with appearance of similar electric activity from the circular muscle. Electric activity and colonic pressure increased upon increase in the colonic distension until the balloon in the proximal part of the ascending colon moved to the transverse colon in one mass contraction. Ten minutes after longitudinal muscle anesthetization, no electric activity was recorded from the longitudinal and circular muscles upon colonic distension. CONCLUSIONS: The electric waves appear to be transmitted from the longitudinal to the circular muscle upon colonic distension. The giant migrating contractions of the colon that move the food bolus from the cecum to the transverse colon are suggested to be a function of the longitudinal muscle electric activation with gut lumen modulation by the circular fibers.     

Mechanisms of shock wave induced endothelial cell injury

BACKGROUND AND OBJECTIVES: Medical procedures, for example, laser angioplasty and extracorporeal lithotripsy as well as high-energy trauma expose human tissues to shock waves (SWs) that may cause tissue injury. The mechanisms for this injury, often affecting blood vessel walls, are poorly understood. Here we sought to assess the role of two suggested factors, viz., cavitation or reactive oxygen species (ROS). STUDY DESIGN/MATERIALS AND METHODS: A laser driven flyer-plate model was used to expose human umbilical cord vein endothelial cell (HUVEC) monolayers to SWs or to SWs plus cavitation (SWC). Cell injury was quantified with morphometry, trypan blue staining, and release of (51)Cr from labeled HUVECs. RESULTS: HUVECs, exposed to SWs only, could not be distinguished from controls in morphological appearance or ability to exclude trypan blue. Yet, release of (51)Cr, indicated a significant cell injury (P < 0.05). HUVEC cultures exposed to SWC, exhibited cell detachment and cell membrane damage detectable with trypan blue. Release of (51)Cr was fourfold compared to SW samples (P < 0.01). Signs of cell injury were evident at 15 minutes and did not change over the next 4 hours. No protective effects of ROS scavengers were demonstrated. CONCLUSIONS: Independent of ROS, SWC generated an immediate cell injury, which can explain, for example, vessel wall perturbation described in relation to SW treatments and trauma.     

Photomechanical delivery of 100-nm microspheres through the stratum corneum: implications for transdermal drug delivery

BACKGROUND AND OBJECTIVES: Photomechanical waves (PWs) render the stratum corneum permeable and allow molecules to diffuse into the epidermis. The aim of this study was to investigate the probe size that could be delivered through the stratum corneum and into the epidermis. STUDY DESIGN/MATERIALS AND METHODS: A single PW was applied onto the rat skin in vivo. Aqueous suspensions of fluorescent microspheres, 100 nm in diameter, were used as probes for transdermal delivery. The presence of the microspheres in the epidermis was measured by a fiber-based spectrofluorimeter after the stratum corneum was removed by tape-stripping (TS). RESULTS: Exposure of the rat skin to a PW permeabilized the stratum corneum and allowed the fluorescent microspheres to diffuse into the epidermis. CONCLUSIONS: The experiments show that PWs can facilitate the delivery of very large molecules and probes into the epidermis.     

远红外线治疗仪(TDP)特定电磁波肛部理疗对直肠癌Miles术后恢复的作用

目的评价TDP特定电磁波肛部理疗对直肠癌Miles术后患者恢复的治疗效果。方法1999年6月～2004年6月，将102名直肠癌Miles术后患者随机分为对照组及治疗组两组。治疗组自术后第2天开始使用TDP治疗器照射肛部伤口。前瞻性比较两组术后疼痛评分、运动功能指数、排便受阻时间、住院时间及创面愈合时间的差异。结果治疗组术后第8、15天疼痛评分，第10、20天运动功能指数，排便受阻时间，住院时间及创面愈合时间与对照组比较差异均有显著性（P〈0．05或0．01）。结论TDP特定电磁波肛部理疗能促进直肠癌Miles术后患者肛部伤口的恢复。     

ST-T改变与Q-T离散度

体表十二导联心电图不同导联间最长、最短Q-T间期的差值即:QT离散度(QTdispersion,QTd)。通过QT离散度可反映心室复极的不均一性和电不稳定性。如果心肌复极不均匀性增加,心肌细胞膜电位差增加,易形成多发性折返,导致心肌的传导和自律性异常,促发各种心律失常,甚至室颤的发生。因此QT离散度在临床上的应用越来越被重视,在本文中也显示出在缺血性心脏病中有一定的作用。在体表十二导联心电图上测量、计算QT离散度最为简便、无创伤、重复性好。     

Initiation sites for Ca2+ signals in endothelial cells

Intracellular Ca²⁺ signals in response to inositol 1,4,5-trisphosphate-producing agents often present themselves as Ca²⁺ oscillations and propagating Ca²⁺ waves originating at discrete initiation sites. We studied the spatial organization of the Ca²⁺ signal in single CPAE endothelial cells stimulated with adenosine triphosphate. The long, thin processes presented a higher agonist sensitivity and, for the same agonist concentration, a faster rise in cytoplasmic Ca²⁺ concentration and rate of wave propagation than the cell body. Ca²⁺ waves originated preferentially in one of these processes and then invaded the cell body. Removal of external Ca²⁺ induced a progressive inhibition up to blockade of the response in the process but not in the cell body. These findings suggest that CPAE cells contain many individual store units, each of which has the inherent ability to set the stage for Ca²⁺ release. A diffusing messenger originating from the initiation zone then coordinates the events leading to Ca²⁺ release in the individual store units to produce a Ca²⁺ wave.     

Working memory and preparation elicit different patterns of slow wave event-related brain potentials

Some event-related brain potential (ERP) studies of working memory have used delayed match-to-sample designs in which a stimulus (S1) is held in memory for comparison with a subsequent stimulus (S2). During the S1-S2 interval, ERP slow negativities varied with both the type and amount of material held in working memory. One interpretation is that these slow waves index working memory operations. An alternative explanation is that they only reflect general preparatory processing for the response to S2. To decide between these explanations, we used two visual processing tasks that required similar preparation for S2. In one task, visual memory rehearsal operations were required. During the S1-S2 interval, there were clear differences between the amplitudes, topographies, and the effect of information load on the slow waves in the two tasks, thus ruling out preparation only as an explanation.     

Endothelial function and outdoor temperature

Studies within populations consistently showed that cardiovascular mortality increases with hot weather. However, the biological mechanisms underlying this association remain largely unknown. Endothelial function plays a pivotal role in the pathogenesis of cardiovascular disease. Therefore, we investigated the association between endothelial function and outdoor temperature. We measured flow-mediated vasodilatation (FMD) as index of endothelial function in 274 randomly recruited subjects (50% women, mean age 40.6 year). Both before (partial r = −0.14, p = 0.017) and after adjustment (partial r = −0.17, p = 0.006) for sex, age, body mass index, brachial artery diameter and current smoking, FMD was negatively associated with mean daily temperature. The odds of endothelial dysfunction increased by 58% (95% CI: 4–141%; p = 0.03) for each 10 °C increment in mean daily temperature during the week before the examination. Our findings suggest that endothelial dysfunction might contribute to the increase in cardiovascular morbidity and mortality associated with hot weather.