Classification of spatiotemporal hemodynamics from brain perfusion MR images using expectation-maximization estimation with finite mixture of multivariate gaussian distributions.

The ability to cluster different perfusion compartments in the brain is critical for analyzing brain perfusion. This study presents a method based on a mixture of multivariate Gaussians (MoMG) and the expectation-maximization (EM) algorithm to dissect various perfusion compartments from dynamic susceptibility contrast (DSC) MR images so that each compartment comprises pixels of similar signal-time curves. This EM-based method provides an objective way to 1) delineate an area to serve as the in-plane arterial input function (AIF) of the feeding artery for adjacent tissues to better quantify the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT); 2) demarcate regions with abnormal perfusion derangement to facilitate diagnosis; and 3) obtain parametric maps with supplementary information, such as temporal scenarios and recirculation of contrast agent. Results from normal subjects show that perfusion cascade manifests (in order of appearance) the arteries, gray matter (GM), white matter (WM), veins and sinuses, and choroid plexus mixed with cerebrospinal fluid (CSF). The averaged rCBV, rCBF, and MTT ratios between GM and WM are in good agreement with those in the literature. Results from a patient with cerebral arteriovenous malformation (CAVM) showed distinct spatiotemporal characteristics between perfusion patterns, which allowed differentiation between pathological and nonpathological areas.     

Influence of bradykinin B1 and B2 receptors in the immune response triggered by renal ischemia–reperfusion injury

Bradykinin B1 receptors are exclusively expressed in inflamed tissues. For this reason, they have been related with the outcomes of several pathologies. Ischemia–reperfusion injury is caused by the activation of inflammatory and cytoprotective genes, such as macrophage chemoattractant protein-1 and heme oxygenase-1, respectively. This study was aimed to analyze the involvement of bradykinin B1 and B2 receptors (B1R and B2R) in tissue response after renal ischemia–reperfusion injury. For that, B1R (B1−/−), B2R (B2−/−) knockout animals and its control (wild-type mice, B1B2+/+) were subjected to renal bilateral ischemia, followed by 24, 48 and 120 h of reperfusion. At these time points, blood serum samples were collected for creatinine and urea dosages. Kidneys were harvested for histology and molecular analyses by real-time PCR. At 24 and 48 h of reperfusion, B1−/− group resulted in the lowest serum creatinine and urea levels, indicating less renal damage, which was proved by renal histology. Renal protection associated with B1−/− mice was also related with higher expression of HO-1 and lower expression of MCP-1. In conclusion, the absence of B1R had a protective role against inflammatory responses developed after renal ischemia–reperfusion injury.     

舒张功能障碍对冠心病的诊断价值

目的应用超声多普勒方法评价冠心病患者的左室整体舒张功能及舒张功能障碍的发生率，探讨舒张功能障碍在冠心病无创诊断中的价值。方法对入选病人行常规检查，同时进行二尖瓣血流频谱、肺静脉血流频谱及二尖瓣环组织多普勒检查，对比临床标准与舒张功能障碍标准对冠心病的诊断率。结果舒张功能障碍标准对冠心病的检出率显著高于临床标准。结论舒张功能检查可作为冠心病诊断的初筛检查。     

兔膝关节持续被动活动对前交叉韧带重建术后切口局部组织血氧饱和度的影响

目的 探讨膝关节持续被动活动（continuous passive motion, CPM）对兔前交叉韧带重建术后切口局部组织血氧饱和度的影响. 方法 20 只八月龄雄性新西兰大白兔右侧后肢膝关节行自体双股半腱肌腱移植重建前交叉韧带手术,术后随机分为2组：自由活动组（n＝10）和CPM组（n＝10）.自由活动组笼内自由活动;CPM组应用兔膝关节持续被动活动器运动.术后第2天,近红外光技术装置ODISseyTM 局部组织血氧监护仪测量每一来回（屈曲30°～110°）不同CPM速度（分别为2.35°/s、3.2°/s 、8°/s）时的切口局部组织血氧饱和度（tissue oxygen saturation ,StO2）变化,选择最好的CPM范围和速度.分别在术前和术后第2、4、6、8、10、14天观察膝关节CPM不同角度时切口局部组织StO2的变化. 结果 与自由活动组相比,3种速度的CPM在不同屈曲角度下均保持较高的StO2,且有显著性差异（P＜0.05）,不同CPM速度之间StO2有显著性差异（P＜0.05）.每一来回（屈曲30°～110°）运动速度为3.2°/s时保持最高的StO2.在术前和术后第2、4、6、8、10、14天等各时间点,膝关节屈曲30°、60°、90°、110°时StO2均无显著性差异（P＞0.05）,不同的时间点（术前和术后第2、4、6、8、10、14天）切口的StO2差别均有显著统计学意义（P＜0.05）.术后第2～4天最低,然后逐渐上升.术后第2周拆线后,切口愈合良好,没有感染、血肿和切口裂开. 结论 兔膝前交叉韧带重建术后第2天开始进行膝关节CPM（屈曲30°～110°）,可增加切口局部组织血氧饱和度,以3.2°/s的CPM速度最佳.     

An automated on-line method for simultaneous analysis of phenothiazines in human serum by high-performance liquid chromatography/sonic spray ionization mass spectrometry using backflush column switching

An automated on-line method for simultaneous analysis of five phenothiazine drugs by high-performance liquid chromatography (HPLC)/sonic spray ionization mass spectrometry (SSI-MS) has been established, using backflush column switching. A 400-μl portion of serum sample diluted 81-fold with distilled water was subjected to the on-line system. In the system, an Oasis HLB cartridge was used as the precolumn for extraction; large molecules such as proteins in serum were discarded by use of distilled water containing 0.1% formic acid as a mobile phase. After switching a valve, the analytes trapped in the precolumn were eluted in the backflush mode and separated by a Chromolith Performance RP-18e column, which is composed of C₁₈-bonded monolithic silica. The column effluents were then introduced into the SSI-MS. The present method provided successful separation and determination of six phenothiazines including an internal standard. Satisfactory linearities, reproducibility, and sensitivity were obtained at concentration levels that matched the toxic levels of phenothiazines. All drug peaks appeared within 18 min, and the system could be reequilibrated in only about 8 min for the next run. Because of the simplicity and rapidness of the method, it is likely to be useful in the fields of emergency medicine and forensic toxicology.     

术前无创正压通气治疗对脊柱侧凸患者围手术期肺功能的影响

目的:研究术前使用呼吸机无创正压通气治疗对脊柱侧凸患者围手术期肺功能的影响。方法:将40例Cobb角≥60°、肺功能存在中度以上限制性通气功能障碍、行脊柱侧凸矫形术的脊柱侧凸患者,随机分成A组和B组,每组20例。A组在术前采用BiPAP呼吸机,经用面罩无创正压通气(NIPPV)治疗1个月;B组常规术前准备。观察A组患者治疗前后肺功能的改善及两组患者围手术期肺功能的差异。结果:两组患者性别、年龄、身高、体重、Cobb角度、手术时间、手术径路、融合椎体数等基本情况比较无统计学差异(P>0.05);A组患者经NIPPV治疗后肺活量(VC)、肺活量占预计值的百分比(VC%)、用力肺活量(FVC)、第一秒最大呼气量(FEV1.0)、最大通气量(MVV)和最大通气量占预计值的百分比(MVV%)较治疗前明显改善(P<0.01);两组患者术中氧合指数、术后拔管时间、拔管后15min动脉血气PO2、PCO2比较有显著性差异(P<0.05)。结论:术前无创正压通气治疗可改善脊柱侧凸患者围手术期的肺功能,可缩短手术后气管插管的拔管时间,改善术后通气功能,有助于脊柱侧凸患者手术后早期恢复。     

Stigma rises despite antiretroviral roll-out: A longitudinal analysis in South Africa

Stigma is a recognised problem for effective prevention, treatment, and care of HIV/AIDS. However, few studies have measured changes in the magnitude and character of stigma over time. This paper provides the first quantitative evaluation in Africa of the changing nature of stigma and the potential determinants of these changes. More specifically, it evaluates the dynamic relationship between stigma and (1) increased personal contact with people living with HIV/AIDS and (2) knowing people who died of AIDS. Panel survey data collected in Cape town 2003 and 2006 for 1074 young adults aged 14–22 years were used to evaluate changes in three distinct dimensions of stigma: behavioural intentions towards people living with HIV/AIDS; instrumental stigma; and symbolic stigma. Individual fixed effects regression models are used to evaluate factors that influence stigma over time. Each dimension of stigma increased in the population as a whole, and for all racial and gender sub-groups. Symbolic stigma increased the most, followed by instrumental stigma, while negative behavioural intentions showed a modest increase. Knowing someone who died of AIDS was significantly associated with an increase in instrumental stigma and symbolic stigma, while increased personal contact with people living with HIV/AIDS was not significantly associated with any changes in stigma. Despite interventions, such as public-sector provision of antiretroviral treatment (which some hoped would have reduced stigma), stigma increased among a sample highly targeted with HIV-prevention messages. These findings emphasise that changes in stigma are difficult to predict and thus important to monitor. They also indicate the imperative for renewed efforts to reduce stigma, perhaps through interventions to weaken the association between HIV/AIDS and death, to reduce fear of HIV/AIDS, and to recast HIV as a chronic manageable disease.     

应用复合小梁切除术治疗具有手术失败高危因素青光眼的临床观察

个月的术后观察及随访,39眼眼压<21mmHg,成功率为70 %.9眼+药物治疗眼压<30mmHg,总有效率为84%.8例手术失败,其中1例为发育型青光眼,7例为新生血管性青光眼.并发症持续性低眼压发生率7.1 %,低眼压性黄斑变性1.7%.结论 对具有手术失败高危因素青光眼的复合小梁切除术与传统小梁切除术相比可明显提高好手术成功率.如药物浓度及作用时间适当,其抗增殖药物副作用的并发症与传统小梁切除术并发症闭角无明显提高.