Objective: The beneficial effect of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has been well established, but there is the problem of no-reflow phenomenon which is an a...Objective: The beneficial effect of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has been well established, but there is the problem of no-reflow phenomenon which is an adverse prognostic factor in primary PCI. In the present study the effect of a distal protection device (PercuSurge GuardWire; GW) on epicardial blood flow and myocardial perfusion was evaluated. Methods and Results: Patients with AMI were randomly divided into 2 groups, the GW and the control groups. The GW group included 52 patients with AMI who underwent primary PCI with GW protection and the control group included 60 patients who underwent primary PCI without GW protection. Epicardial blood flow in the infarct-related artery (IRA) and myocardial perfusion were evaluated according to the thrombolysis in myocardial infarction (TIMI) flow grade and the myocardial blush grade (MBG). We found TIMI score of 3 was obtained significantly more frequently in the GW group (96%) than in the control group (80%). The MBG score of 3 was obtained also significantly greater in the GW group (65%) than in the control group (33%). Conclusion: Primary PCI with GW protection can significantly improve epicardial blood flow and myocardial perfusion.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
AIM： To investigate the usefulness of direct hemoperfusion with a polymyxin B-immobilized fiber column （DHP-PMX therapy） for warm hepatic ischemia-reperfusion （I/R） injury after total hepatic vascular exclusion ...AIM： To investigate the usefulness of direct hemoperfusion with a polymyxin B-immobilized fiber column （DHP-PMX therapy） for warm hepatic ischemia-reperfusion （I/R） injury after total hepatic vascular exclusion （THVE） using a porcine model. METHODS： Eleven Mexican hairless pigs weighing 22-38 kg were subjected to THVE for 120 min and then observed for 360 min. The animals were divided into two groups randomly： the DHP-PMX group （n = 5） underwent DHP-PMX at a flow rate of 80 mL/min for 220 min （beginning 10 rain before reperfusion）, while the control group did not （n = 6）. The rate pressure product （RPP）： heart rate x end-systolic arterial blood pressure, hepatic tissue blood flow （HTBF）, portal vein blood flow （PVBF）, and serum aspartate aminotransferase （AST） levels were compared between the two groups. RESULTS： RPP and HTBF were significantly （P 〈 0.05） higher in the DHP-PMX group than in the control group 240 and 360 min after reperfusion. PVBF in the DHP-PMX group was maintained at about 70% of the flow before ischemia and differed significantly （P 〈 0.05） compared to the control group 360 min after reperfusion. The serum AST increased gradually after reperfusion in both groups, but the AST was significantly （P 〈 0.05） lower in the DHP-PMX group 360 min after reperfusion. CONCLUSION： DHP-PMX therapy reduced the hepatic warm I/R injury caused by THVE in a porcine model.展开更多
Blinking is regarded as the continuous interrupted eyelid closure or opening and its thermal effect will compromise between these two. During a blink, the heat loss via convection, radiation and tear evaporation from ...Blinking is regarded as the continuous interrupted eyelid closure or opening and its thermal effect will compromise between these two. During a blink, the heat loss via convection, radiation and tear evaporation from cornea is prevented, warm tear is lay- ered across corneal surface and the vessels of the palpebral conjunctiva provide heat to anterior eye. In most of the thermal models in human eye that are found in literatures, effect of blinking is not included, simulation is carried out only in open eye. Thus, in this paper, thermal effects of blinking are investigated using one-dimensional finite element method in transient state case. The bio-heat transfer process is simulated during different blinking rates, lid closure and opening. The simulation is carried out using normal and extreme values of ambient temperatures, blood temperatures, evaporation rates, blood perfusion rates, and lens thermal conduetivities. Blinking is found to increase corneal and lens temperature by 1.29℃ and 0.78℃ respectively when compared to open eye. The results obtained from this model are useful in predicting temperature distribution in different laser eye surgeries, hyperthermia and cryosurgery treatment of eyelid carci- noma, choroidal melanoma and can be used for diagnosing temperature-related diseases.展开更多
文摘Objective: The beneficial effect of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has been well established, but there is the problem of no-reflow phenomenon which is an adverse prognostic factor in primary PCI. In the present study the effect of a distal protection device (PercuSurge GuardWire; GW) on epicardial blood flow and myocardial perfusion was evaluated. Methods and Results: Patients with AMI were randomly divided into 2 groups, the GW and the control groups. The GW group included 52 patients with AMI who underwent primary PCI with GW protection and the control group included 60 patients who underwent primary PCI without GW protection. Epicardial blood flow in the infarct-related artery (IRA) and myocardial perfusion were evaluated according to the thrombolysis in myocardial infarction (TIMI) flow grade and the myocardial blush grade (MBG). We found TIMI score of 3 was obtained significantly more frequently in the GW group (96%) than in the control group (80%). The MBG score of 3 was obtained also significantly greater in the GW group (65%) than in the control group (33%). Conclusion: Primary PCI with GW protection can significantly improve epicardial blood flow and myocardial perfusion.
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.
文摘AIM： To investigate the usefulness of direct hemoperfusion with a polymyxin B-immobilized fiber column （DHP-PMX therapy） for warm hepatic ischemia-reperfusion （I/R） injury after total hepatic vascular exclusion （THVE） using a porcine model. METHODS： Eleven Mexican hairless pigs weighing 22-38 kg were subjected to THVE for 120 min and then observed for 360 min. The animals were divided into two groups randomly： the DHP-PMX group （n = 5） underwent DHP-PMX at a flow rate of 80 mL/min for 220 min （beginning 10 rain before reperfusion）, while the control group did not （n = 6）. The rate pressure product （RPP）： heart rate x end-systolic arterial blood pressure, hepatic tissue blood flow （HTBF）, portal vein blood flow （PVBF）, and serum aspartate aminotransferase （AST） levels were compared between the two groups. RESULTS： RPP and HTBF were significantly （P 〈 0.05） higher in the DHP-PMX group than in the control group 240 and 360 min after reperfusion. PVBF in the DHP-PMX group was maintained at about 70% of the flow before ischemia and differed significantly （P 〈 0.05） compared to the control group 360 min after reperfusion. The serum AST increased gradually after reperfusion in both groups, but the AST was significantly （P 〈 0.05） lower in the DHP-PMX group 360 min after reperfusion. CONCLUSION： DHP-PMX therapy reduced the hepatic warm I/R injury caused by THVE in a porcine model.
文摘Blinking is regarded as the continuous interrupted eyelid closure or opening and its thermal effect will compromise between these two. During a blink, the heat loss via convection, radiation and tear evaporation from cornea is prevented, warm tear is lay- ered across corneal surface and the vessels of the palpebral conjunctiva provide heat to anterior eye. In most of the thermal models in human eye that are found in literatures, effect of blinking is not included, simulation is carried out only in open eye. Thus, in this paper, thermal effects of blinking are investigated using one-dimensional finite element method in transient state case. The bio-heat transfer process is simulated during different blinking rates, lid closure and opening. The simulation is carried out using normal and extreme values of ambient temperatures, blood temperatures, evaporation rates, blood perfusion rates, and lens thermal conduetivities. Blinking is found to increase corneal and lens temperature by 1.29℃ and 0.78℃ respectively when compared to open eye. The results obtained from this model are useful in predicting temperature distribution in different laser eye surgeries, hyperthermia and cryosurgery treatment of eyelid carci- noma, choroidal melanoma and can be used for diagnosing temperature-related diseases.
