Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve domi...Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist.This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential.In this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital.The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage.In the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings.In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral sclerosis.In addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores.These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position,and that this method is more suitable for monitoring disease progression than the traditional montage.This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.展开更多
The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and...The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.展开更多
α-smooth muscle actin （α-SMA） and tenascin-C are stress-induced phenotypic features of myofibroblasts. The expression levels of these two proteins closely correlate with the extracellular mechanical microenvironme...α-smooth muscle actin （α-SMA） and tenascin-C are stress-induced phenotypic features of myofibroblasts. The expression levels of these two proteins closely correlate with the extracellular mechanical microenvironment. We investigated how the expression of α-SMA and tenascin-C was altered in the periodontal ligament （PDL） under orthodontic loading to indirectly reveal the intrinsic mechanical microenvironment in the PDL. In this study, we demonstrated the synergistic effects of transforming growth factor-β1 （TGF-β1） and mechanical tensile or compressive stress on myofibroblast differentiation from human periodontal ligament cells （hPDLCs）. The hPDLCs under higher tensile or compressive stress significantly increased their levels of α-SMA and tenascin-C compared with those under lower tensile or compressive stress. A similar trend was observed in the tension and compression areas of the PDL under continuous light or heavy orthodontic load in rats. During the time-course analysis of expression, we observed that an increase in α-SMA levels was matched by an increase in tenascin-C levels in the PDL under orthodontic load in vivo. The time-dependent variation of α-SMA and tenascin-C expression in the PDL may indicate the time-dependent variation of intrinsic stress under constant extrinsic loading.展开更多
The effects of dismerinone (DMR), a derivative of milrinone, on high K+ depolarized slow response action potentials (APs) and intracellular cAMP levels were studied in guinea pig papillary muscles. DMR induced slow AP...The effects of dismerinone (DMR), a derivative of milrinone, on high K+ depolarized slow response action potentials (APs) and intracellular cAMP levels were studied in guinea pig papillary muscles. DMR induced slow APs in high K+ depolorized guinea pig papillary muscles and increased APA, Vmaxand APD50 of the slow APs in dose dependent way ; cAMP levels in same preparations were elevated by DMR. These effects of DMR are similar to isoprenaline (ISO). Bead adrenocepter blocker propranolol had no influence on DMR effect. Overall, the results from this study suggested that effects of DMR were not related to Beta adrenocepter, and might be related to its inhibiting phosphodiesterase Ⅲ(PDE Ⅲ) action.展开更多
The effect of Ce3+ on cardiac muscle of rat and guinea pig was studied. In vitro, 0.05 mmol·L-1 solution of Ce3+ inhibited the contraction of guinea pig atria. The change of action potential duration(APD) of gui...The effect of Ce3+ on cardiac muscle of rat and guinea pig was studied. In vitro, 0.05 mmol·L-1 solution of Ce3+ inhibited the contraction of guinea pig atria. The change of action potential duration(APD) of guinea pig papillary muscle exposed to 0.4 mmol·L-1 Ce3+ was significant, and those exposed to 0.1 and 0. 2 mmol·L-1 Ce3+ were not significant. In vivo, compared with the control group, the APD for rat cardiac muscle after long-term feed on Ce3+ was significantly delayed in high dose, and that was not significantly delayed in low dose. The results suggest that Ce3+ with long-term high dose intake might affect the influx of Ca2+, Na+ and outflow of K+ for rat cardiac muscle.展开更多
The effects of iodium-heterocyclic compound（3,6-di-[dimethytamino]-dibcnzopyrodoniun formate,IHC-64）on the action potentials and contractile force of the isolatedguinca pig papillary muscles were investigatad.50 μm...The effects of iodium-heterocyclic compound（3,6-di-[dimethytamino]-dibcnzopyrodoniun formate,IHC-64）on the action potentials and contractile force of the isolatedguinca pig papillary muscles were investigatad.50 μmol/L IHC-64 only inhibited contractile forceand had no effect on APA,dv/dt max,APD<sub>5</sub>0 and APD<sub>9</sub>0 of fast action potentials in Tyrode’s so-lution.All of these parametres were depressed by further increasing concentration of IHC-64.InK-rich Tyrodc’s solution,the depressive action of IHC-64 on slow action potentials andcontractile force could be antagonized by incrcased extracellular calcium.These results suggesr thatIHC-64 inhibit not only slow calcium influx but also fast sodium influx,and it may.（?）new calci-urn channd blockcr.展开更多
The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening ...The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening of APD50 produced by THP was concentration dependent,APD90was shortened only at higher concentrations of THP,APA and Vmax were decreased by increasing theTHP concentration to 100 and 300 μmol/L. In Veutricular muscles,THP,at higher Concentration,shortened APDs,and APD90 The reductions of Vmax and APA were significant only at highest concentration,300 μmol/L,ERP was relatively prolonged in both Purldnje fibers and ventricular muscles.These studies suggest that THP may inhibit Ca2+ and Na+ movement across the membrane of myocardlal cells.展开更多
Objective:To investigate the changes of left ventricular papillary muscle action potentials in guinea pigs with iron deficiency anemia and heart failure.Methods:A total of 20 cases of iron deficiency anemia with heart...Objective:To investigate the changes of left ventricular papillary muscle action potentials in guinea pigs with iron deficiency anemia and heart failure.Methods:A total of 20 cases of iron deficiency anemia with heart failure were treated with experimental group and 10 normal guinea pigs as control group. Blood samples were collected to determine hemoglobin content, red blood cell number and whole blood iron index, and the changes of cardiac function and hemodynamics were detected by 6240 biological signal collection system to determine whether the model was successful or not, Intracellular microelectrode technique was used to determine the action potentials of the papillary muscles in the model group and the control group. the potential amplitudes (APA), overshoot values (APA), maximum depolarization rate (Vmax), 20 % of repolarization, 50 % and 90 % of repolarization (APD20, APD50 and APD90 ) and the average velocity of repolarization were measured. Compare statistical difference between the model group and the control group.Results: 14 cases of model group survived completely, compared with control group, APD50 and APD90 prolonged, and the average velocity decreased.Conclusions: the action potential repolarization duration in the guinea pig papillary muscle of iron deficiency anemia with heart failure is prolonged, and the average repolarization velocity is slow.展开更多
About 75% of all bladder cancer diagnosed are non-muscle invasive bladder cancer(NMIBC), recurring over 50% of them after transurethral resection of the bladder tumor. In order to prevent recurrences, adjuvant intrave...About 75% of all bladder cancer diagnosed are non-muscle invasive bladder cancer(NMIBC), recurring over 50% of them after transurethral resection of the bladder tumor. In order to prevent recurrences, adjuvant intravesical chemotherapy with mitomycin C and immunotherapy with bacillus Calmette-Gu-érin(BCG) is traditionally used. Unfortunately, many patients relapse after receiving these treatments and a significant proportion of them require surgery. After a one-to-three years BCG maintenance, the risk for progression at 5 years was 19.3% for T1G3 tumors. Many new treatment approaches are being investigated to increase the effectiveness of adjuvant intravesical therapy. One of the developing treatments for intermediate and high-risk NMIBC is the combination of intravesical chemotherapy and hyperthermia, called chemohyperthermia. This article provides a review of the mechanism of action, current status and indications, results and future perspectives.展开更多
We identified that oncological treatments in general (chemotherapies, immunotherapies and radiotherapies) frequently cause peripheral neuropathy, including cramps, characterized by excess protons due to metabolic and ...We identified that oncological treatments in general (chemotherapies, immunotherapies and radiotherapies) frequently cause peripheral neuropathy, including cramps, characterized by excess protons due to metabolic and neuronal factors, such as sudden changes in pH, uremia and aspects that affect neuromotor functions. Such situations and others like them are often neglected in treatment, which naturally concerns itself with the main problem: Cancer. Sometimes toxic solutions are implemented that have comorbid side effects, such as duloxetine (standard treatment). Based on monitoring of cancer patients who used the non-toxic product, called “Magicramp® Electrostatic Charge Reduction Cushion” (MECRC), approved in Europe more than 10 years ago, we carried out a controlled test in Brazil. In this clinical trial, we hypothesized that reducing excessive ionic charges (electrostatic charge), which is one of the side effects often described in the literature as “Chemotherapy-Induced Peripheral Neuropathy” (CIPN), would decrease or eliminate cramping, under the hypothesis that such elimination would prevent or attenuate muscular vulnerability to action impulses, and increase the power of relaxation through the same mechanism. In this double-blind and randomized clinical trial, 40 (forty) adult patients with muscle cramps caused by oncological treatments were tested, evaluating the degree of efficiency of the product that aims to reduce muscle cramps, by eliminating and/or reducing excess loads electrostatic ionic. Data from the clinical research conducted in this study are available online at https://doi.org/10.7910/DVN/QUS94U.展开更多
基金supported by the National Natural Science Foundation of China,Nos.81873784,82071426Clinical Cohort Construction Program of Peking University Third Hospital,No.BYSYDL2019002(all to DSF)。
文摘Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist.This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential.In this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital.The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage.In the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings.In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral sclerosis.In addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores.These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position,and that this method is more suitable for monitoring disease progression than the traditional montage.This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.
文摘The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.
基金funded by National Nature Science Foundation of China (Grant Nos 30970705, 11172190, 81371171, and 81371172)
文摘α-smooth muscle actin （α-SMA） and tenascin-C are stress-induced phenotypic features of myofibroblasts. The expression levels of these two proteins closely correlate with the extracellular mechanical microenvironment. We investigated how the expression of α-SMA and tenascin-C was altered in the periodontal ligament （PDL） under orthodontic loading to indirectly reveal the intrinsic mechanical microenvironment in the PDL. In this study, we demonstrated the synergistic effects of transforming growth factor-β1 （TGF-β1） and mechanical tensile or compressive stress on myofibroblast differentiation from human periodontal ligament cells （hPDLCs）. The hPDLCs under higher tensile or compressive stress significantly increased their levels of α-SMA and tenascin-C compared with those under lower tensile or compressive stress. A similar trend was observed in the tension and compression areas of the PDL under continuous light or heavy orthodontic load in rats. During the time-course analysis of expression, we observed that an increase in α-SMA levels was matched by an increase in tenascin-C levels in the PDL under orthodontic load in vivo. The time-dependent variation of α-SMA and tenascin-C expression in the PDL may indicate the time-dependent variation of intrinsic stress under constant extrinsic loading.
文摘The effects of dismerinone (DMR), a derivative of milrinone, on high K+ depolarized slow response action potentials (APs) and intracellular cAMP levels were studied in guinea pig papillary muscles. DMR induced slow APs in high K+ depolorized guinea pig papillary muscles and increased APA, Vmaxand APD50 of the slow APs in dose dependent way ; cAMP levels in same preparations were elevated by DMR. These effects of DMR are similar to isoprenaline (ISO). Bead adrenocepter blocker propranolol had no influence on DMR effect. Overall, the results from this study suggested that effects of DMR were not related to Beta adrenocepter, and might be related to its inhibiting phosphodiesterase Ⅲ(PDE Ⅲ) action.
基金the National Natural Science Foundation of China!29671034
文摘The effect of Ce3+ on cardiac muscle of rat and guinea pig was studied. In vitro, 0.05 mmol·L-1 solution of Ce3+ inhibited the contraction of guinea pig atria. The change of action potential duration(APD) of guinea pig papillary muscle exposed to 0.4 mmol·L-1 Ce3+ was significant, and those exposed to 0.1 and 0. 2 mmol·L-1 Ce3+ were not significant. In vivo, compared with the control group, the APD for rat cardiac muscle after long-term feed on Ce3+ was significantly delayed in high dose, and that was not significantly delayed in low dose. The results suggest that Ce3+ with long-term high dose intake might affect the influx of Ca2+, Na+ and outflow of K+ for rat cardiac muscle.
文摘The effects of iodium-heterocyclic compound（3,6-di-[dimethytamino]-dibcnzopyrodoniun formate,IHC-64）on the action potentials and contractile force of the isolatedguinca pig papillary muscles were investigatad.50 μmol/L IHC-64 only inhibited contractile forceand had no effect on APA,dv/dt max,APD<sub>5</sub>0 and APD<sub>9</sub>0 of fast action potentials in Tyrode’s so-lution.All of these parametres were depressed by further increasing concentration of IHC-64.InK-rich Tyrodc’s solution,the depressive action of IHC-64 on slow action potentials andcontractile force could be antagonized by incrcased extracellular calcium.These results suggesr thatIHC-64 inhibit not only slow calcium influx but also fast sodium influx,and it may.（?）new calci-urn channd blockcr.
文摘The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening of APD50 produced by THP was concentration dependent,APD90was shortened only at higher concentrations of THP,APA and Vmax were decreased by increasing theTHP concentration to 100 and 300 μmol/L. In Veutricular muscles,THP,at higher Concentration,shortened APDs,and APD90 The reductions of Vmax and APA were significant only at highest concentration,300 μmol/L,ERP was relatively prolonged in both Purldnje fibers and ventricular muscles.These studies suggest that THP may inhibit Ca2+ and Na+ movement across the membrane of myocardlal cells.
文摘Objective:To investigate the changes of left ventricular papillary muscle action potentials in guinea pigs with iron deficiency anemia and heart failure.Methods:A total of 20 cases of iron deficiency anemia with heart failure were treated with experimental group and 10 normal guinea pigs as control group. Blood samples were collected to determine hemoglobin content, red blood cell number and whole blood iron index, and the changes of cardiac function and hemodynamics were detected by 6240 biological signal collection system to determine whether the model was successful or not, Intracellular microelectrode technique was used to determine the action potentials of the papillary muscles in the model group and the control group. the potential amplitudes (APA), overshoot values (APA), maximum depolarization rate (Vmax), 20 % of repolarization, 50 % and 90 % of repolarization (APD20, APD50 and APD90 ) and the average velocity of repolarization were measured. Compare statistical difference between the model group and the control group.Results: 14 cases of model group survived completely, compared with control group, APD50 and APD90 prolonged, and the average velocity decreased.Conclusions: the action potential repolarization duration in the guinea pig papillary muscle of iron deficiency anemia with heart failure is prolonged, and the average repolarization velocity is slow.
文摘About 75% of all bladder cancer diagnosed are non-muscle invasive bladder cancer(NMIBC), recurring over 50% of them after transurethral resection of the bladder tumor. In order to prevent recurrences, adjuvant intravesical chemotherapy with mitomycin C and immunotherapy with bacillus Calmette-Gu-érin(BCG) is traditionally used. Unfortunately, many patients relapse after receiving these treatments and a significant proportion of them require surgery. After a one-to-three years BCG maintenance, the risk for progression at 5 years was 19.3% for T1G3 tumors. Many new treatment approaches are being investigated to increase the effectiveness of adjuvant intravesical therapy. One of the developing treatments for intermediate and high-risk NMIBC is the combination of intravesical chemotherapy and hyperthermia, called chemohyperthermia. This article provides a review of the mechanism of action, current status and indications, results and future perspectives.
文摘We identified that oncological treatments in general (chemotherapies, immunotherapies and radiotherapies) frequently cause peripheral neuropathy, including cramps, characterized by excess protons due to metabolic and neuronal factors, such as sudden changes in pH, uremia and aspects that affect neuromotor functions. Such situations and others like them are often neglected in treatment, which naturally concerns itself with the main problem: Cancer. Sometimes toxic solutions are implemented that have comorbid side effects, such as duloxetine (standard treatment). Based on monitoring of cancer patients who used the non-toxic product, called “Magicramp® Electrostatic Charge Reduction Cushion” (MECRC), approved in Europe more than 10 years ago, we carried out a controlled test in Brazil. In this clinical trial, we hypothesized that reducing excessive ionic charges (electrostatic charge), which is one of the side effects often described in the literature as “Chemotherapy-Induced Peripheral Neuropathy” (CIPN), would decrease or eliminate cramping, under the hypothesis that such elimination would prevent or attenuate muscular vulnerability to action impulses, and increase the power of relaxation through the same mechanism. In this double-blind and randomized clinical trial, 40 (forty) adult patients with muscle cramps caused by oncological treatments were tested, evaluating the degree of efficiency of the product that aims to reduce muscle cramps, by eliminating and/or reducing excess loads electrostatic ionic. Data from the clinical research conducted in this study are available online at https://doi.org/10.7910/DVN/QUS94U.
