AIM To determine the optimum resting tension(ORT) for in vitro human pulmonary artery(PA) ring preparations.METHODS Pulmonary arteries were dissected from disease free sections of the resected lung in the operating th...AIM To determine the optimum resting tension(ORT) for in vitro human pulmonary artery(PA) ring preparations.METHODS Pulmonary arteries were dissected from disease free sections of the resected lung in the operating theatre and tissue samples were directly sent to the laboratory in Krebs-Henseleit solution(Krebs).The pulmonary arteries were then cut into 2 mm long rings.PA rings were mounted in 25 m L organ baths or 8 m L myograph chambers containing Krebs compound(37 ℃,bubbled with 21% O_2:5% CO_2) to measure changes in isometric tension.The resting tension was set at 1-gram force(gf) with vessels being left static to equilibrate for duration of one hour.Baseline contractile reactions to 40 mmol/L KCl were obtained from a resting tension of 1 gf.Contractile reactions to 40 mmol/L KCl were then obtained from stepwise increases in resting tension(1.2,1.4,1.6,1.8 and 2.0 gf).RESULTS Twenty PA rings of internal diameter between 2-4 mmwere prepared from 4 patients.In human PA rings incrementing the tension during rest stance by 0.6 gf,up to 1.6 gf significantly augmented the 40 mmol/L KCl stimulated tension.Further enhancement of active tension by 0.4 gf,up to 2.0 gf mitigate the 40 mmol/L KCl stimulated reaction.Both Myograph and the organ bath demonstrated identical conclusions,supporting that the radial optimal resting tension for human PA ring was 1.61 g.CONCLUSION The radial optimal resting tension in our experiment is 1.61 gf(15.78 m N) for human PA rings.展开更多
There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca2+-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from th...There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca2+-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from the fast-relaxing phase was investigated for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius in vitro, in comparison to the single exponential model and the classical bi-exponential model. During repetitive stimulations at a 2-s interval by square pulses of a 2-ms duration at 12 V direct currency (DC), the isometric tension of Bufo gastrocnemius was recorded at 100 Hz. The relaxation curve with tensions falling from 90% of the peak to the 15th datum before next stimulation was analyzed by three exponential models using a program in MATLAB 6.5. Both the goodness of fit and the distribution of the residuals for the best fitting sup- ported the comparable validity of this new bi-exponential model for kinetic analysis of the relaxation process of the control muscles. After CPA treatment, however, this new bi-exponential model showed an obvious statistical superiority for kinetic analysis of the muscle relaxation process, and it gave the estimated rest tension consistent to that by experimentation, whereas both the classical bi-exponential model and the single exponential model gave biased rest tensions. Moreover, after the treatment of muscles by CPA, both the single exponential model and the classical bi-exponential model yielded lowered relaxation rates, nevertheless, this new bi-exponential model had relaxation rates of negligible changes except much higher rest tensions. These results suggest that this novel linearly-combined bi-exponential model is desirable for kinetic analysis of the relaxation process of muscles with altered Ca2+-pumping activity.展开更多
Tension-type headache（TTH） is the most prevalent type of primary headache. Many studies have shown that the pathogenesis of primary headache is associated with fine structural or functional changes. However, these s...Tension-type headache（TTH） is the most prevalent type of primary headache. Many studies have shown that the pathogenesis of primary headache is associated with fine structural or functional changes. However, these studies were mainly based on migraine. The present study aimed to investigate whether TTH patients show functional disturbances compared with healthy subjects. We used restingstate functional magnetic resonance imaging（f MRI） and regional homogeneity（Re Ho） analysis to identify changes in the local synchronization of spontaneous activity in patients with TTH. Ten patients with TTH and 10 age-, gender-, and education-matched healthy controls participated in the study. After demographic and clinical characteristics were acquired, a 3.0-T MRI system was used to obtain restingstate f MRIs. Compared with healthy controls, the TTH group exhibited significantly lower Re Ho values in the bilateral caudate nucleus, the precuneus, the putamen, the left middle frontal gyrus, and the superior frontal gyrus. There was no correlation between mean Re Ho values in TTH patients and duration of TTH, number of attacks, duration of daily attacks, Visual Analogue Scale score, or Headache Impact Test-6 score. These results suggest that TTHpatients exhibit reduced synchronization of neuronal activity in multiple regions involved in the integration and processing of pain signals.展开更多
本文以肌钙蛋白抑制亚基(troponin I subunit,TnI)作为肌节蛋白降解的分子标记,探讨舒张期肌纤维内Ca2+浓度升高与肌原纤维降解的关系。采用在收缩期增加肌质网(sarcoplasmic reticulum,SR)钙离子释放通道开放机率的caffeine,以及在舒...本文以肌钙蛋白抑制亚基(troponin I subunit,TnI)作为肌节蛋白降解的分子标记,探讨舒张期肌纤维内Ca2+浓度升高与肌原纤维降解的关系。采用在收缩期增加肌质网(sarcoplasmic reticulum,SR)钙离子释放通道开放机率的caffeine,以及在舒张期引起SR钙离子释放通道钙漏的H2O2,灌流大鼠离体比目鱼肌,以Western blot技术检测TnI表达水平,并比较其降解程度。结果显示,离体比目鱼肌肌条在40min无钙Krebs液灌流期间,静息张力未见明显改变,发展张力缓慢降低,TnI未发生降解。用低浓度caffeine(1与5mmol/L)灌流肌条,静息张力仅在疲劳收缩期间短暂升高,对肌条疲劳程度与疲劳后的恢复速率均无显著性影响,灌流后肌条的TnI未发生降解;高浓度caffeine(10mmol/L)灌流使静息张力持续升高,肌条易发生疲劳,且疲劳收缩后肌条的发展张力不能恢复,TnI发生明显降解。H2O2灌流对肌条疲劳程度没有明显影响,疲劳收缩后发展张力呈迅速恢复后较快下降,静息张力持续增加,且呈浓度依赖性。用1mmol/L H2O2灌流肌条,TnI未发生降解,用5与10mmol/L H2O2灌流肌条时,TnI降解程度随浓度增大而增加。由于肌条静息张力与舒张期间肌纤维内Ca2+浓度密切相关,以上结果提示,舒张期SR钙离子释放通道钙漏增加,可能引起肌纤维TnI降解。展开更多
文摘AIM To determine the optimum resting tension(ORT) for in vitro human pulmonary artery(PA) ring preparations.METHODS Pulmonary arteries were dissected from disease free sections of the resected lung in the operating theatre and tissue samples were directly sent to the laboratory in Krebs-Henseleit solution(Krebs).The pulmonary arteries were then cut into 2 mm long rings.PA rings were mounted in 25 m L organ baths or 8 m L myograph chambers containing Krebs compound(37 ℃,bubbled with 21% O_2:5% CO_2) to measure changes in isometric tension.The resting tension was set at 1-gram force(gf) with vessels being left static to equilibrate for duration of one hour.Baseline contractile reactions to 40 mmol/L KCl were obtained from a resting tension of 1 gf.Contractile reactions to 40 mmol/L KCl were then obtained from stepwise increases in resting tension(1.2,1.4,1.6,1.8 and 2.0 gf).RESULTS Twenty PA rings of internal diameter between 2-4 mmwere prepared from 4 patients.In human PA rings incrementing the tension during rest stance by 0.6 gf,up to 1.6 gf significantly augmented the 40 mmol/L KCl stimulated tension.Further enhancement of active tension by 0.4 gf,up to 2.0 gf mitigate the 40 mmol/L KCl stimulated reaction.Both Myograph and the organ bath demonstrated identical conclusions,supporting that the radial optimal resting tension for human PA ring was 1.61 g.CONCLUSION The radial optimal resting tension in our experiment is 1.61 gf(15.78 m N) for human PA rings.
基金Project supported by the National Natural Science Foundation of China (No. 30472139)the Education Commission for the First Batch of Excellent Young Teachers in Universities of Chongqing City, China
文摘There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca2+-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from the fast-relaxing phase was investigated for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius in vitro, in comparison to the single exponential model and the classical bi-exponential model. During repetitive stimulations at a 2-s interval by square pulses of a 2-ms duration at 12 V direct currency (DC), the isometric tension of Bufo gastrocnemius was recorded at 100 Hz. The relaxation curve with tensions falling from 90% of the peak to the 15th datum before next stimulation was analyzed by three exponential models using a program in MATLAB 6.5. Both the goodness of fit and the distribution of the residuals for the best fitting sup- ported the comparable validity of this new bi-exponential model for kinetic analysis of the relaxation process of the control muscles. After CPA treatment, however, this new bi-exponential model showed an obvious statistical superiority for kinetic analysis of the muscle relaxation process, and it gave the estimated rest tension consistent to that by experimentation, whereas both the classical bi-exponential model and the single exponential model gave biased rest tensions. Moreover, after the treatment of muscles by CPA, both the single exponential model and the classical bi-exponential model yielded lowered relaxation rates, nevertheless, this new bi-exponential model had relaxation rates of negligible changes except much higher rest tensions. These results suggest that this novel linearly-combined bi-exponential model is desirable for kinetic analysis of the relaxation process of muscles with altered Ca2+-pumping activity.
基金supported by the National Natural Science Foundation of China (81071140)
文摘Tension-type headache（TTH） is the most prevalent type of primary headache. Many studies have shown that the pathogenesis of primary headache is associated with fine structural or functional changes. However, these studies were mainly based on migraine. The present study aimed to investigate whether TTH patients show functional disturbances compared with healthy subjects. We used restingstate functional magnetic resonance imaging（f MRI） and regional homogeneity（Re Ho） analysis to identify changes in the local synchronization of spontaneous activity in patients with TTH. Ten patients with TTH and 10 age-, gender-, and education-matched healthy controls participated in the study. After demographic and clinical characteristics were acquired, a 3.0-T MRI system was used to obtain restingstate f MRIs. Compared with healthy controls, the TTH group exhibited significantly lower Re Ho values in the bilateral caudate nucleus, the precuneus, the putamen, the left middle frontal gyrus, and the superior frontal gyrus. There was no correlation between mean Re Ho values in TTH patients and duration of TTH, number of attacks, duration of daily attacks, Visual Analogue Scale score, or Headache Impact Test-6 score. These results suggest that TTHpatients exhibit reduced synchronization of neuronal activity in multiple regions involved in the integration and processing of pain signals.
