Cardiopulmonary exercise test predicts sustained ventricular arrhythmias in chronic heart failure

Background

The cardiopulmonary exercise test (CPX) is an affordable tool for risk prediction in patients with chronic heart failure (CHF). We aimed to determine the role of CPX parameters in predicting the risk of incidence of sustained ventricular arrhythmias (SVA) in CHF.

Methods

Sixty-one consecutive patients with CHF enrolled in the Daunia Heart Failure Registry underwent CPX and were followed for 327 ± 247 days. Clinical follow-up was performed every month and anticipated in case of re-hospitalisation for cardiac disease. Incidence of SVA was evaluated by direct clinical examination (ECG, ambulatory ECG).

Results

Patients with episodes of SVA (N 14) showed lower values of pVO2 and PetCO2, and higher values of VE/VCO2, VE/VCO2 slope, and VE%. After correction for age, gender, diabetes, ischaemic heart disease and left ventricular ejection fraction, peak VO2 (hazard ratio (HR) 0.68, 95 % confidence interval (CI) 0.51–0.91, p < 0.05), VE% (HR 1.38, 95 % CI 1.04–1.84, p < 0.05), VE/VCO2 (HR 1.38, 95 % CI 1.04–1.82, p < 0.05), VE/VCO2 slope (HR 1.77, 95 % CI 1.31–2.39, p < 0.01), PetCO2 (HR 0.66, 95 % CI 0.50–0.88, p < 0.01) were found as predictors of SVA. At Kaplan-Meier analysis, lower event-free rates were found in subjects with peak VO2 values below median (log rank p < 0.05), values of VE/VCO2 above mean (p < 0.05), higher VE/VCO2 slope tertiles (p <0.05), and values of PetCO2 below median (p < 0.05).

Conclusions

CPX provides prognostic independent information for risk of SVA in subjects with CHF.     

血管回声跟踪技术评价慢性肾功能衰竭患者股总动脉内皮功能

目的：应用血管回声跟踪技术（echo-tracking,ET）评价慢性肾功能衰竭患者股总动脉内皮功能,并探讨该技术治疗慢性肾衰患者心血管并发症的临床意义。方法：选择2012年1月至12月在我院就诊的82例慢性肾功能衰竭患者为观察组,另选47例健康体检者为对照组。应用ET技术检测两组患者的左右侧股总动脉血管弹性指标,包括压力应变弹性系数（Ep）,脉搏波传导速度（PWVβ）,增大指数（AI）,硬度指数（β）和脉顺应性（AC）。观察两组患者的检测结果并进行比较。结果：观察组中,压力应变弹性系数（Ep）,脉搏波传导速度（PWVβ）,增大指数（AI）和硬度指数（β）均高于对照组所对应的值;而脉顺应性（AC）值低于对照组,两组差异有统计学意义（P〈0.05）。观察组中,需要透析的患者组β、PWVβ、Ep和AI的值均高于非透析患者组对应的值,AC值低于非透析患者组的值,差异有统计学意义（P〈0.05）。结论：ET对慢性肾功能衰竭患者心血管并发症的早期治疗,改善患者的愈后具有一定的临床指导意义。     

老年重症肺炎患者机械通气后短期预后的相关影响因素分析

目的：探讨分析该疾病患者短期预后的相关影响因素。方法：对120例老年重症肺炎机械通气患者的临床资料进行回顾性分析,采用Logistic回归分析法,对老年重症肺炎患者的机械通气后的病死率与并发症的相关因素进行分析。结果：病死率为29．17％,经回归分析后,病死率与心力衰竭、电解质紊乱与酸碱失衡、肝功能衰竭以及呼吸衰竭等因素有关（P〈0．05）;而与循环衰竭、胃肠损害（消化道出血异常）以及气胸等因素无关（P〉0．05）;影响患者短期预后的独立预测因素包括：高急性生理与慢性健康评分（APACHEII）、高急性生理学评分（APS）、低格拉斯哥昏迷（GCS）评分以及低白蛋白水平。结论：老年重症肺炎患者机械通气后,能够引起心力衰竭等症状,影响患者短期预后情况的重要因素。     

小鼠慢性高眼压模型下视网膜神经节细胞的损伤

目的:通过巩膜外静脉烧烙术建立慢性高眼压模型,研究小鼠慢性高眼压状态下视网膜神经节细胞的凋亡情况.方法:取C57BL/6J小鼠30只.3只作为空白对照组,其余27只右眼为实验眼,左眼为对照眼.术前用iCare眼压计测量眼压,按巩膜外静脉烧烙法建立慢性高眼压模型,术后用iCare眼压计每日监测眼压.分剐取空白对照组6眼,术后1w、4 w造模成功的小鼠各8只16眼眼球,石蜡切片行Tunel法,荧光显微镜下采集图像.小鼠眼压的组间比较采用t检验.结果:给予巩膜外静脉烧烙术后1d、1w、4w小鼠慢性高眼压眼眼压(11.15±0.98、10.65±0.95、10.35±1.05)与对照眼(6.40±0.95、6.35±1.05、6.50±1.15)相比,差异有统计学意义(t=10.77～18.08,P＜0.001).Tunel法结果显示,正常小鼠空白对照组未见明显凋亡的视网膜神经节细胞.慢性高眼压组术后1w、4w可见Tunel阳性表达.而对照组术后1w及4w均未见Tunel阳性表达.结论:巩膜外静脉烧灼法能诱导出持续的肯定的小鼠慢性高眼压模型,慢性高眼压状态下小鼠视网膜神经节细胞发生凋亡,细胞凋亡是小鼠慢性高眼压状态下视网膜神经节细胞损伤的主要方式.     

COPD患者改善体质量指数与肺功能变化的相关性

目的:探讨COPD患者改善体质量指数(BMD与肺功能变化的相关性.方法:经加强营养达正常BMI的患者(A组)与低BMI的COPD患者(B组),比较2组肺功能指标、6min步行距离、呼吸困难评分.结果:与B组相比,A组FEV1％、FEV1/FVC、SVC、MVV、IC均明显升高(P＜0.01),RV/TLC明显上升(P＜0.01),6min步行距离延长(P＜0.01)、呼吸困难评分明显降低(P＜0.01).Pearson 相关性分析显示,FEV1％、FEV1/FVC、SVC、MVV、IC、RV/TIC与BMI相关,6min步行距离与BMI呈正相关,呼吸困难评分与BMI呈负相关.结论:改善BMI可明显改善COPD患者的肺功能指标,减轻临床症状.     

儿童链球菌性肺炎的季节特点及病原菌的耐药性分析

目的:回顾性分析因肺炎就诊我院的儿童其感染肺炎链球菌对青霉素等临床常用抗生素的耐药性.方法:调阅2008年一月-2012年1月间,所有因肺炎入住我院并在我院治愈的患儿病历及呼吸道标本中的细菌分离、培养、耐药性报告单,剔除其他病原菌所致的儿童肺炎,仅针对分离出的388株肺炎链球菌药敏结果进行回顾性分析.结果:选定的研究期间内,肺炎链球菌所致的儿童肺炎有鲜明的季节特点,以冬春,秋冬交替时段高发.肺炎链球菌对青霉素的耐药率呈逐年上升趋势,分别为48.9％、53.8％、52.6％和55.7％.另外,统计还发现SP对临床常用的抗生素如头孢呋辛(77.8％)、阿奇霉素(82.0％)、红霉素(86.9％)、四环素(79.9％)、克林霉素(80.9％)、甲氧苄啶/磺胺甲恶唑(69.1％)等的耐药性也较以往的报道为高.尽管SP的耐药性较为严峻,但SP对临床部分抗生素尚具有较高的敏感性,这其中比较敏感的包括头孢噻肟、头孢曲松、美罗培南、万古霉素、氧氟沙星以及利奈唑胺,这给临床使用抗生素治疗SP所致的感染性肺炎提供了很好的取舍参考.结论:链球菌所致的儿童肺炎具有鲜明的季节特点,经典的治疗药物青霉素的耐药逐年升高,本地区儿童肺炎链球菌的耐药情况较为严峻,使用抗生素治疗SP感染时应注意参考药敏试验结果.     

厄贝沙坦对慢性心力衰竭患者血清骨桥蛋白水平的影响

目的:探讨厄贝沙坦对心力衰竭(心衰)患者血清骨桥蛋白(OPN)水平及心功能的影响.方法:选择心衰患者106例,随机分为两组,并随机接受厄贝沙坦治疗,每组均为53例,常规治疗组,予以利尿剂、洋地黄制剂和β受体阻滞剂常规治疗,厄贝沙坦组,在常规治疗下加用厄贝沙坦150 mg/d,治疗12周,比较治疗前后各组患者血清OPN、B型利钠肽(BNP)水平、左室射血分数(LVEF)及左室舒张末内径(LVEDd).结果:心衰患者随着心衰程度的加重,血清OPN、BNP水平及LVEDd逐渐升高,而LVEF逐渐降低(P＜0.0l);与治疗前相比,治疗后两组患者血清OPN及BNP水平均明显降低(P＜0.01),而LVEF升高,LVEDd降低(P＜0.05),但厄贝沙坦组OPN、BNP水平及LVEF、LVEDd较常规治疗组变化更显著(P＜0.05).结论:OPN可反映心衰严重程度及判断患者的预后,在常规心衰治疗的基础上加服厄贝沙坦能进一步降低血清OPN水平,改善心功能及心衰患者的预后.     

顺尔宁对稳定期慢性阻塞性肺疾病患者的疗效分析

目的：探讨顺尔宁治疗稳定期慢性阻塞性肺疾病（COPD）患者的临床效果。方法：将60例稳定期COPD患者随机分为研究组和对照组,每组各30例。经2周洗脱期后,对照组采用常规治疗,研究组在常规治疗基础上加用顺尔宁治疗,共治疗4周。比较两组患者肺功能参数、血气分析、生活质量以及血清LTB4、IL-8浓度的变化。结果：治疗后两组患者的肺功能参数、血气分析指标和生活质量均有改善,研究组肺功能参数改善程度较对照组显著（P〈0．05）;研究组的生活质量改善明显优于对照组（P〈0．05）：治疗后两组患者的血清LTB4、IL-8水平较治疗前均下降,且研究组明显低于对照组（P〈0．05）。结论：顺尔宁能降低稳定期慢性阻塞性肺疾病患者血清LTB4、IL-8含量,改善患者肺功能及血气分析指标,有效提高患者的生命质量,值得临床推广。     

Chronic hypoxia leads to a glycolytic phenotype and suppressed HIF-2 signaling in PC12 cells

Background

Along with other regulators of cell metabolism, hypoxia-inducible factors HIF-1 and HIF-2 differentially regulate cell adaptation to hypoxia. Switches in HIF-1/HIF-2 signaling in chronic hypoxia have not been fully investigated.

Methods

Proliferation, viability, apoptosis, neuronal and bioenergetic markers, mitochondrial function, respiration, glycolysis, HIF signalling, responses to O₂ and glucose deprivation (OGD) were examined using tumor PC12 and SH-SY5Y cells continuously grown at 3% O₂.

Results

Hypoxic PC12 cells (H-cells) exhibit reduced proliferation and histone H4 acetylation, NGF-independent differentiation, activation of AMPK, inhibition of Akt, altered mitochondria and response to NGF. Cellular cytochrome c is increased with no effect on apoptosis. Reduction in respiration has minor effect on cellular ATP which is maintained through activated uptake (GLUT1) and utilization (HK2, PFK2) of glucose. H-cells exhibit resistance to OGD linked to increased glycogen stores. HIF-2alpha protein is decreased without changes in mRNA. Unlike HIF-1alpha, HIF-2alpha is not stabilized pharmacologically or by O₂ deprivation. Capacity for HIF-2alpha stabilization is partly restored when H-cells are cultured at normoxia. In low-respiring SH-SY5Y cells cultured under the same conditions HIF-2alpha stabilization and energy budget are not affected.

Conclusions

In chronically hypoxic PC12 cells glycolytic energy budget, increased energy preservation and low susceptibility to OGD are observed. HIF-2alpha no longer orchestrates adaptive responses to anoxia.

General significance

Demonstrated switch in HIF-1/HIF-2 signaling upon chronic hypoxia can facilitate cell survival in energy crisis, by regulating balance between energy saving and decrease in proliferation, on one hand and active cell growth and tumor expansion, on the other.     

Relationship of Chronotype to Sleep,Light Exposure,and Work-Related Fatigue in Student Workers

Students who work during the school year face the potential of sleep deprivation and its effects, since they have to juggle between school and work responsibilities along with social life. This may leave them with less time left for sleep than their nonworking counterparts. Chronotype is a factor that may exert an influence on the sleep of student workers. Also, light and social zeitgebers may have an impact on the sleep-related problems of this population. This study aimed to document sleep, light exposure patterns, social rhythms, and work-related fatigue of student workers aged 19–21 yrs and explore possible associations with chronotype. A total of 88 student workers (mean?±?SD: 20.18?±?.44 yrs of age; 36 males/52 females) wore an actigraph (Actiwatch-L; Mini-Mitter/Respironics,Bend, OR) and filled out the Social Rhythm Metric for two consecutive weeks during the school year. Also, they completed the Morningness-Eveningness Questionnaire (MEQ), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Occupational Fatigue Exhaustion/Recovery Scale (OFER). Repeated and one-way analyses of variance (ANOVAs), Pearson's chi-square tests, and correlation coefficients were used for statistical comparisons. Subjects slept an average of 06:28?h/night. Actigraphic sleep parameters, such as sleep duration, sleep efficiency, wake after sleep onset, and sleep latency, did not differ between chronotypes. Results also show that evening types (n?=?17) presented lower subjective sleep quality than intermediate types (n?=?58) and morning types (n?=?13). Moreover, evening types reported higher levels of chronic work-related fatigue, exhibited less regular social rhythms, and were exposed to lower levels of light during their waking hours (between 2 and 11 h after wake time) as compared to intermediate types and morning types. In addition, exposure to light intensities between 100 and 500 lux was lower in evening types than in intermediate types and morning types. However, bright light exposure (≥1000 lux) did not differ between chronotypes. In conclusion, results suggest that student workers may constitute a high-risk population for sleep deprivation. Evening types seemed to cope less well with sleep deprivation, reporting poorer sleep quality and higher levels of work-related fatigue than intermediate types and morning types. The higher chronic work-related fatigue of evening types may be linked to their attenuated level of light exposure and weaker social zeitgebers. These results add credence to the hypothesis that eveningness entails a higher risk of health-impairing behaviors. (Author correspondence: luc.laberge@uqac.ca)