Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary micro...Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation,but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography(MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction,respectively,and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall,MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice,but the approval of regulatory authorities is lacking.展开更多
Background： Large-scale muscle tissue engineering remains a major challenge. An axial vascular pedicle and perfusion bioreactor are necessary for the development and maintenance of large-scale engineered muscle to en...Background： Large-scale muscle tissue engineering remains a major challenge. An axial vascular pedicle and perfusion bioreactor are necessary for the development and maintenance of large-scale engineered muscle to ensure circulation within the construct. We aimed to develop a novel experimental model of a large-scale engineered muscle flap from an existing rat groin fat flap. Methods： A fat flap based on the superficial interior epigastric vascular pedicle was excised from rats and placed into a perfusion bioreactor. The flaps were kept in the bioreactor for up to 7 weeks, and transdifferentiation of adipose to muscle tissue could have taken place. This system enabled myogenic-differentiation medium flow through the bioreactor at constant pH and oxygen concentration. Assessment of viability was pertbrmed by an immunofluorescence assay, histological staining, a calcein-based live/dead test, and through determination of RNA quantity and quality after 1, 3, 5, and 7 weeks. Results： Immunofluorescence staining showed that smooth muscle around vessels was still intact without signs of necrosis or atrophy. The visual assessment of viability by the calcein-based live/dead test revealed viability of the rat adipose tissue preserved in the bioreactor system with permanent perfusion. RNA samples from different experimental conditions were quantified by spectrophotometry, and intact bands of 18S and 28S rRNA were detected by gel electrophoresis, indicating that degradation of RNA was minimal. Conclusions： Flow perfusion maintains the long-term viability of a rat groin engineered muscle flap in vitro, and a large-scale vascularized muscle could be engineered in a perfusion bioreactor.展开更多
目的:应用多普勒超声观察体外循环(cardiopulmonary bypass,CPB)不同灌注流量对颈动脉血流的影响。方法:选择2014年12月至2015年1月在湘雅医院择期行瓣膜置换术或室间隔缺损修补术的患者共45例。分为G1,G2,G3组,灌注流量分别为(62±...目的:应用多普勒超声观察体外循环(cardiopulmonary bypass,CPB)不同灌注流量对颈动脉血流的影响。方法:选择2014年12月至2015年1月在湘雅医院择期行瓣膜置换术或室间隔缺损修补术的患者共45例。分为G1,G2,G3组,灌注流量分别为(62±2),(72±2),(82±2)mL/(kg·min)。在麻醉前(T1),麻醉后(T2),CPB开始后10 min(T3),20 min(T4),40 min(T5),60 min(T6)及CPB结束后20 min(T7),利用便携式多普勒超声诊断仪行颈总动脉(common carotid artery,CCA)和颈内动脉(internal carotid artery,ICA)测量,并记录灌注流量、颈总动脉管径(diameter of common carotid artery,CCAD)、颈总动脉峰值流速(peak velocity of common carotid artery,CCAV)、颈总动脉血流量(flow of common carotid artery,CCAF)、颈内动脉管径(diameter of internal carotid artery,ICAD)、颈内动脉峰值流速(peak velocity of internal carotid artery,ICAV)和颈内动脉血流量(flow of internal carotid artery,ICAF)。用α稳态法在CPB期间转机前(P1)、CPB期间体温降至最低(P2)、CPB复温至35℃(P3)、CPB停止后20 min(P4)和2 h(P5)行血气分析,对比血红蛋白(hemoglobin,Hb)和乳酸水平。记录手术时间、CPB时间、主动脉阻断时间,术后患者拔管时间、ICU时间、术后住院时间及术后并发症的情况。结果:3组患者Hb和乳酸的差异无统计学意义(均P>0.05)。组内比较:P2~P5各时间点的Hb水平均比P1的低,差异均有统计学意义(均P<0.05),在P2和P3时Hb水平最低。P3~P5各时间点的乳酸水平均比P1的高,差异均有统计学意义(均P<0.05)。麻醉前患者左右两侧CCAD,CCAV,CCAF,ICAD,ICAV,ICAF比较差异均无统计学意义(均P>0.05)。3组患者间CCAV和CCAF差异无统计学意义(均P>0.05)。组内比较:T2~T6的CCAV较T1明显下降(P<0.05);T7的CCAV较T3~T6明显回升(均P<0.05),但仍然明显低于T1(P<0.05)。T2~T5的CCAF与T1比较差异有统计学意义(均P<0.05)。在T3时,G1组的ICAV低于G3组(P<0.05);在T4时,G1组的ICAV低于G2组,G2组的ICAV低展开更多
Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods...Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods:Twenty-four CAD patients and 19 cognitively normal(CN)age-matched controls were recruited.A retinal function imager(RFI,Optical Imaging Ltd.,Rehovot,Israel)was used to measure the retinal blood flow supplying the macular area of a diameter of 2.5 mm centered on the fovea.Blood flow volumes of arterioles(entering the macular region)and venules(exiting the macular region)of the supplied area were calculated.Macular blood flow was calculated as the average of arteriolar and venular flow volumes.Custom ultra-high-resolution optical coherence tomography(UHR–OCT)was used to calculate macular tissue volume.Automated segmentation software(Orion,Voxeleron LLC,Pleasanton,CA)was used to segment six intra-retinal layers in the 2.5 mm(diameter)area centered on the fovea.The inner retina(containing vessel network),including retinal nerve fiber layer(RNFL),ganglion cell-inner plexiform layer(GCIPL),inner nuclear layer(INL)and outer plexiform layer(OPL),was segmented and tissue volume was calculated.Perfusion was calculated as the flow divided by the tissue volume.Results:The tissue perfusion in CAD patients was 2.58±0.79 nl/s/mm^(3)(mean±standard deviation)and was significantly lower than in CN subjects(3.62±0.44 nl/s/mm^(3),P<0.01),reflecting a decrease of 29%.The flow volume was 2.82±0.92 nl/s in CAD patients,which was 31%lower than in CN subjects(4.09±0.46 nl/s,P<0.01).GCIPL tissue volume was 0.47±0.04 mm^(3) in CAD patients and 6%lower than CN subjects(0.50±0.05 mm^(3),P<0.05).No other significant alterations were found in the intra-retinal layers between CAD and CN participants.Conclusions:This study is the first to show decreased retinal tissue perfusion that may be indicative of diminished tissue metabolic activity in patients with clinical Alzheimer’s disease.展开更多
Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insuff iciency of perfusion, is a common mechanism for tiss...Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insuff iciency of perfusion, is a common mechanism for tissue death or degeneration, and at a lower threshold, a mechanism for the generation of sensory signalling including pain. It is of considerable interest to study perfusion of pe- ripheral abdominal tissues in a variety of circumstances. Microvascular disease of the abdominal organs has been implicated in the pathogenesis of a variety of disorders, including peptic ulcer disease, inflammatory bowel disease and chest pain. The basic principle of laser Doppler perfusion monitoring (LDPM) is to analyze changes in the spectrum of light reflected from tissues as a response to a beam of monochromatic laser light emitted. It reflects the total local microcirculatory blood perfusion, including perfusion in capillaries, arterioles, venules and shunts. During the last 20-25 years, numerous studies have been performed in different parts of the gastroin-testinal (GI) tract using LDPM. In recent years we have developed a multi-modal catheter device which includes a laser Doppler probe, with the intent primarily to investigate patients suffering from functional chest pain of presumed oesophageal origin. Preliminary studies show the feasibility of incorporating LDPM into such catheters for performing physiological studies in the GI tract. LDPM has emerged as a research and clinical tool in preference to other methods; but, it is important to be aware of its limitations and account for them when reporting results.展开更多
文摘Our understanding of coronary syndromes has evolved in the last two decades out of the obstructive atherosclerosis of epicardial coronary arteries paradigm to include anatomo-functional abnormalities of coronary microcirculation. No current diagnostic technique allows direct visualization of coronary microcirculation,but functional assessments of this circulation are possible. This represents a challenge in cardiology. Myocardial contrast echocardiography(MCE) was a breakthrough in echocardiography several years ago that claimed the capability to detect myocardial perfusion abnormalities and quantify coronary blood flow. Research demonstrated that the integration of quantitative MCE and fractional flow reserve improved the definition of ischemic burden and the relative contribution of collaterals in non-critical coronary stenosis. MCE identified no-reflow and low-flow within and around myocardial infarction,respectively,and predicted the potential functional recovery of stunned myocardium using appropriate interventions. MCE exhibited diagnostic performances that were comparable to positron emission tomography in microvascular reserve and microvascular dysfunction in angina patients. Overall,MCE improved echocardiographic evaluations of ischemic heart disease in daily clinical practice,but the approval of regulatory authorities is lacking.
文摘Background： Large-scale muscle tissue engineering remains a major challenge. An axial vascular pedicle and perfusion bioreactor are necessary for the development and maintenance of large-scale engineered muscle to ensure circulation within the construct. We aimed to develop a novel experimental model of a large-scale engineered muscle flap from an existing rat groin fat flap. Methods： A fat flap based on the superficial interior epigastric vascular pedicle was excised from rats and placed into a perfusion bioreactor. The flaps were kept in the bioreactor for up to 7 weeks, and transdifferentiation of adipose to muscle tissue could have taken place. This system enabled myogenic-differentiation medium flow through the bioreactor at constant pH and oxygen concentration. Assessment of viability was pertbrmed by an immunofluorescence assay, histological staining, a calcein-based live/dead test, and through determination of RNA quantity and quality after 1, 3, 5, and 7 weeks. Results： Immunofluorescence staining showed that smooth muscle around vessels was still intact without signs of necrosis or atrophy. The visual assessment of viability by the calcein-based live/dead test revealed viability of the rat adipose tissue preserved in the bioreactor system with permanent perfusion. RNA samples from different experimental conditions were quantified by spectrophotometry, and intact bands of 18S and 28S rRNA were detected by gel electrophoresis, indicating that degradation of RNA was minimal. Conclusions： Flow perfusion maintains the long-term viability of a rat groin engineered muscle flap in vitro, and a large-scale vascularized muscle could be engineered in a perfusion bioreactor.
文摘目的:应用多普勒超声观察体外循环(cardiopulmonary bypass,CPB)不同灌注流量对颈动脉血流的影响。方法:选择2014年12月至2015年1月在湘雅医院择期行瓣膜置换术或室间隔缺损修补术的患者共45例。分为G1,G2,G3组,灌注流量分别为(62±2),(72±2),(82±2)mL/(kg·min)。在麻醉前(T1),麻醉后(T2),CPB开始后10 min(T3),20 min(T4),40 min(T5),60 min(T6)及CPB结束后20 min(T7),利用便携式多普勒超声诊断仪行颈总动脉(common carotid artery,CCA)和颈内动脉(internal carotid artery,ICA)测量,并记录灌注流量、颈总动脉管径(diameter of common carotid artery,CCAD)、颈总动脉峰值流速(peak velocity of common carotid artery,CCAV)、颈总动脉血流量(flow of common carotid artery,CCAF)、颈内动脉管径(diameter of internal carotid artery,ICAD)、颈内动脉峰值流速(peak velocity of internal carotid artery,ICAV)和颈内动脉血流量(flow of internal carotid artery,ICAF)。用α稳态法在CPB期间转机前(P1)、CPB期间体温降至最低(P2)、CPB复温至35℃(P3)、CPB停止后20 min(P4)和2 h(P5)行血气分析,对比血红蛋白(hemoglobin,Hb)和乳酸水平。记录手术时间、CPB时间、主动脉阻断时间,术后患者拔管时间、ICU时间、术后住院时间及术后并发症的情况。结果:3组患者Hb和乳酸的差异无统计学意义(均P>0.05)。组内比较:P2~P5各时间点的Hb水平均比P1的低,差异均有统计学意义(均P<0.05),在P2和P3时Hb水平最低。P3~P5各时间点的乳酸水平均比P1的高,差异均有统计学意义(均P<0.05)。麻醉前患者左右两侧CCAD,CCAV,CCAF,ICAD,ICAV,ICAF比较差异均无统计学意义(均P>0.05)。3组患者间CCAV和CCAF差异无统计学意义(均P>0.05)。组内比较:T2~T6的CCAV较T1明显下降(P<0.05);T7的CCAV较T3~T6明显回升(均P<0.05),但仍然明显低于T1(P<0.05)。T2~T5的CCAF与T1比较差异有统计学意义(均P<0.05)。在T3时,G1组的ICAV低于G3组(P<0.05);在T4时,G1组的ICAV低于G2组,G2组的ICAV低
基金supported by the McKnight Brain Institute,NIH Center Grant P30 EY014801,UM Dean's NIH Bridge Award(UM DBA 2019-3)a grant from Research to Prevent Blindness(RPB)and the North American Neuroophthalmology Society.
文摘Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods:Twenty-four CAD patients and 19 cognitively normal(CN)age-matched controls were recruited.A retinal function imager(RFI,Optical Imaging Ltd.,Rehovot,Israel)was used to measure the retinal blood flow supplying the macular area of a diameter of 2.5 mm centered on the fovea.Blood flow volumes of arterioles(entering the macular region)and venules(exiting the macular region)of the supplied area were calculated.Macular blood flow was calculated as the average of arteriolar and venular flow volumes.Custom ultra-high-resolution optical coherence tomography(UHR–OCT)was used to calculate macular tissue volume.Automated segmentation software(Orion,Voxeleron LLC,Pleasanton,CA)was used to segment six intra-retinal layers in the 2.5 mm(diameter)area centered on the fovea.The inner retina(containing vessel network),including retinal nerve fiber layer(RNFL),ganglion cell-inner plexiform layer(GCIPL),inner nuclear layer(INL)and outer plexiform layer(OPL),was segmented and tissue volume was calculated.Perfusion was calculated as the flow divided by the tissue volume.Results:The tissue perfusion in CAD patients was 2.58±0.79 nl/s/mm^(3)(mean±standard deviation)and was significantly lower than in CN subjects(3.62±0.44 nl/s/mm^(3),P<0.01),reflecting a decrease of 29%.The flow volume was 2.82±0.92 nl/s in CAD patients,which was 31%lower than in CN subjects(4.09±0.46 nl/s,P<0.01).GCIPL tissue volume was 0.47±0.04 mm^(3) in CAD patients and 6%lower than CN subjects(0.50±0.05 mm^(3),P<0.05).No other significant alterations were found in the intra-retinal layers between CAD and CN participants.Conclusions:This study is the first to show decreased retinal tissue perfusion that may be indicative of diminished tissue metabolic activity in patients with clinical Alzheimer’s disease.
文摘Perfusion of individual tissues is a basic physiological process that is necessary to sustain oxygenation and nutrition at a cellular level. Ischemia, or the insuff iciency of perfusion, is a common mechanism for tissue death or degeneration, and at a lower threshold, a mechanism for the generation of sensory signalling including pain. It is of considerable interest to study perfusion of pe- ripheral abdominal tissues in a variety of circumstances. Microvascular disease of the abdominal organs has been implicated in the pathogenesis of a variety of disorders, including peptic ulcer disease, inflammatory bowel disease and chest pain. The basic principle of laser Doppler perfusion monitoring (LDPM) is to analyze changes in the spectrum of light reflected from tissues as a response to a beam of monochromatic laser light emitted. It reflects the total local microcirculatory blood perfusion, including perfusion in capillaries, arterioles, venules and shunts. During the last 20-25 years, numerous studies have been performed in different parts of the gastroin-testinal (GI) tract using LDPM. In recent years we have developed a multi-modal catheter device which includes a laser Doppler probe, with the intent primarily to investigate patients suffering from functional chest pain of presumed oesophageal origin. Preliminary studies show the feasibility of incorporating LDPM into such catheters for performing physiological studies in the GI tract. LDPM has emerged as a research and clinical tool in preference to other methods; but, it is important to be aware of its limitations and account for them when reporting results.
