Sheng-Mai-San(SMS), a well-known Chinese medicinal plant formula, is widely used for the treatment of cardiac diseases characterized by deficiency of Qi and Yin syndrome. A mouse chronic intermittent hypoxia(CIH) mode...Sheng-Mai-San(SMS), a well-known Chinese medicinal plant formula, is widely used for the treatment of cardiac diseases characterized by deficiency of Qi and Yin syndrome. A mouse chronic intermittent hypoxia(CIH) model was established to mimic the primary clinical features of deficiency of Qi and Yin syndrome. Mice experienced CIH for 28 days(nadir 7% to peak 8% oxygen, 20 min per day), resulting in left ventricle(LV) dysfunction and structure abnormalities. After administration of SMS(0.55, 1.1, and 5.5 g·kg-1·d-1) for four weeks, improved cardiac function was observed, as indicated by the increase in the ejection fraction from the LV on echocardiography. SMS also preserved the structural integrity of the LV against eccentric hypotrophy, tissue vacuolization, and mitochondrial injury as measured by histology, electron microscopy, and ultrasound assessments. Mechanistically, the antioxidant effects of SMS were demonstrated; SMS was able to suppress mitochondrial apoptosis as indicated by the reduction of several pro-apoptotic factors(Bax, cytochrome c, and cleaved caspase-3) and up-regulation of the anti-apoptosis factor Bcl-2. In conclusion, these results demonstrate that SMS treatment can protect the structure and function of the LV and that the protective effects of this formula are associated with the regulation of the mitochondrial apoptosis pathway.展开更多
The behavior of large deformations of cellular tissues is usually affected by the local properties of cells and their interactions,resulting in folding which acts as an important role in the embryonic development,as w...The behavior of large deformations of cellular tissues is usually affected by the local properties of cells and their interactions,resulting in folding which acts as an important role in the embryonic development,as well as growing and spreading of a tumor,which can rapidly promote the stereo complexity of the architecture of the tissues.In the present study,a cylindrical vertex model is constructed to explore the morphology of the tubular cell sheets subject to an embedded contractile ring.It is found that an inner region of the contractile ring in equilibrium will protrude from the tube wall,and it will suddenly collapse when the contractile strength exceeds a threshold,indicating the occurrence of a bifurcation.These results on the effect of embedded contraction in the tubular shell are quite different from the planar cases,which can reveal the importance of the interaction between the geometric and material non-linearity in cylindrical geometry.The dependence of the large deformation on the bending modulus parameters and contraction strength is also analyzed for the cylindrical cell shell.展开更多
The incidence of gallstone is higher in patients with diabetes mellitus than in general popula- tion. It is generally attributed to hypomotility and lowered emptying function of the gallblad- der. In this study, we in...The incidence of gallstone is higher in patients with diabetes mellitus than in general popula- tion. It is generally attributed to hypomotility and lowered emptying function of the gallblad- der. In this study, we investigate if chronic hy- perglycemia is correlated with reduced contrac- tile function of the bile ducts in rat. Hypergly- cemic rats were induced by streptozotocin-nic-otinamide treatment. Hyperglycemic rats were sacrificed eight months after induction and bile ducts were removed for the subsequent studies. The bile duct contractility of the normal rats is consistently higher than that of the hypergly- cemic rats. The contractities were measured to be 5.5 ± 0.2 mg vs. 4.2 ± 0.1 mg without CCK stimulation, and 5.5 ± 0.3 mg vs. 7.9 ± 0.4 mg with CCK stimulation, respectively for hypergly-cemic and normal rats. There was no significant difference in plasma CCK concentration in hy- perglycemic rats and normal rats. The expres- sion of CCK-A receptor protein in the bile duct tissue was decreased in hyperglycemic rats compared with that of the normal rats, and it may, at least in part, responsible for a reduced contractility. A reduced bile duct motility may cause bile retention, and may be one of the factors predispose to gallstone formation in type 2 diabetes patients, which is characterized with chronic hyperglycemia.展开更多
Background Cathepsin S and its endogenous inhibitor cystatin C are implicated in the pathogenesis of atherosclerosis,especially in the plaque destabilization and rupture leading to acute coronary syndrome.However, whe...Background Cathepsin S and its endogenous inhibitor cystatin C are implicated in the pathogenesis of atherosclerosis,especially in the plaque destabilization and rupture leading to acute coronary syndrome.However, whether circulating cathepsin S and cystatin C also change in association with coronary plaque morphology is unknown yet. Methods Sprague-Dawley rats were randomly divided into three groups;Sham group,CME group and SB203580 group (n=10 per group).CME rats were produced by injection of 42μm microspheres into the left ventricle with occlusion of the ascending aorta.SB203580,a p38 MAPK inhibitor,was injected into femoral vein after finishing the injection of microspheres in SB203580 group.Left ventricular Ejection Fraction was determined by echocardiography.The level of phosphorylated and total P38 MAPK in myocardium was assessed by Western Blot.Results Left ventricular(LV) Ejection Fraction was depressed at 3 hours and until up to 12 hours in CME group.The increased p38 MAPK activation was observed in CME group.The administration of SB203580 partly inhibited the p38 MAPK activity and preserved cardiac contractile function.Conclusions p38 MAPK is significantly activated by CME and the inhibition of p38 MAPK can partly preserve cardiac contractile function.展开更多
It is not certain whether the myocyte contractile function in the heartfailure is normal according to recent some studies,therefore the contractile functionof the myocytes with the heart failure should be studied. The...It is not certain whether the myocyte contractile function in the heartfailure is normal according to recent some studies,therefore the contractile functionof the myocytes with the heart failure should be studied. The myocyte heart failuremodel was set up by the method of stretching the cultured myocytes,and the myocytes with and without the heart failure were measured the contractile mechanicscharacteristic,the parameters being the maximal contractive velocity of the myocyte(Vmax), the maximal shortening length of myocyte contraction (ΔLmax) and themaximal decrease of the myocyte size during contraction (ΔSmax), by the videoedgedetector system. And then the protein genes (including α-MHC and β-MHC)expression of these myocytes were quantitatively measured by the dot blotting. Thecorrelative and regressive analysis were used to analyze the relationship between themyocyte contractile mechanics characteristic and the contractile protein genes expression level. The results showed that the contractile mechanics parameters,Vmax=41．5±6．0(μm/sec), △Lmax= 10．6±1．9 (% ) and △Smax= 14．3± 2．3 (% ), in themyocytes with the heart failure are statistically significant lower than the normalmyocytes (P<0．01), whose parameters are Vmax=67．9±6．7 (μm/sec), △Lmax=17．7±1．6 (% ) and △Smax=21．5±2．4 (%). The myocyte contractile protein gene (αMHC) expression level in the heart failure myocytes is statistically significant lowerthan that in the normal myocytes,but β-MHC gene expression level is statisticallysignificant higher than the normal myocytes. The α-MllC gene expression level is apositive correlation coefficient with the myocyte contractile mechanics parametersseparately,covering Vmax,△Lmax and △max; but the β- MHC gene expression levelis a negative correlation coefficietn with the myocyte contractile mechanics parameters separately.展开更多
AIM: To investigate the alterations in both structure and contractile responsiveness of ocular ciliary artery(OCA) in spontaneously hypertensive rat(SHR).METHODS: In this experiment, 20-week-old male SHR and Wistar Ky...AIM: To investigate the alterations in both structure and contractile responsiveness of ocular ciliary artery(OCA) in spontaneously hypertensive rat(SHR).METHODS: In this experiment, 20-week-old male SHR and Wistar Kyoto rat(WKY) were studied. The heart rate(HR), the blood pressure(BP; the systolic BP and the diastolic BP) of rats with an electronic sphygmomanometer were measured. Vascular morphometry and isometric tension measurement were used to investigate the alterations in structure and contractility of OCA.RESULTS: A general narrowing of OCAs was observed in SHR compared to the control WYK. In SHR, the media of OCAs were thicker, the luminal diameters were smaller, and the media-to-lumen ratios were higher when compared with WKY(P<0.05). The contractions of OCAs evoked by norepinephrine were smaller in SHR compared to control(P<0.05). Then, OCAs were pretreated with iberiotoxin, L-NAME, or indomethacin 30 min before norepinephrineinduced contraction. Iberiotoxin(0.1 μmol/L) has not changed the norepinephrine-induced contractions in OCAs from both groups. However, L-NAME(100 μmol/L) increased the vasoconstrictions, the increased extents were similar in SHR and WKY(P>0.05). Indomethacin(10 μmol/L) decreased the contractions induced by norepinephrine in OCAs from WKY(P<0.05), but did not change those contractions in vessels from SHR(P>0.05).CONCLUSION: Our results demonstrate that the structure and function of OCAs are altered in hypertension. OCAs from SHR are remodeled with decreased lumen diameter and increased media-to-lumen ratio. Moreover, the contractile responsiveness of OCAs from SHR is diminished due to the disruption of vasoconstrictive effect of prostaglandins.展开更多
While fatty acids play essential roles in the physiology of the myocardium,conventional culture media contain little lipid.We previously revealed that rat neonatal myocardium mainly contains docosahexaenoic(DHA),linol...While fatty acids play essential roles in the physiology of the myocardium,conventional culture media contain little lipid.We previously revealed that rat neonatal myocardium mainly contains docosahexaenoic(DHA),linoleic(LA),and arachidonic(AA)acids as polyunsaturated fatty acids(PUFAs),and these contents in cultured cardiomyocytes derived from fetal rats were markedly lower than those in the neonatal myocardium.In this study,we first assessed the effects of supplementation of DHA,LA,or AA on the fatty acid contents and the percentage change of contractile area in primarily cultured rat cardiomyocytes.Based on this assessment,we then evaluated the effects of DHA or AA supplementation on mRNA expression and further directly measured the contractile force of cardiomyocytes with the supplementations.This study revealed that percentage change of contractile area was maximized under 20μM DHA or 50μM AA supplementation while LA supplementation did not affect this contraction index,and that a widespread upregulation tendency of the mRNA expression related to differentiation,maturity,fatty acid metabolism,and cell adhesion was seen in the cultured cardiomyocytes with supplementation of DHA or AA.In particular,upregulation of the gene expression of cellular adhesion molecules connexin43 and N-cadherin were remarkable,whereas the effects on differentiation and maturation were less pronounced.Correspondingly,the increase of the percentage change of the contractile area of cardiomyocyte clusters in culture dishes with the supplementations was significant,whereas the enhancement of the contractile force was modest.These results suggest that supplementation of DHA or AA to the fetal cardiomyocyte culture may play effective roles in preventing the de-differentiation of the cardiomyocytes in culture and that the enhancement of the contractile performance may be mainly attributed to the improvement of intercellular connection.展开更多
Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harves...Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harvested from gluteus max of adult mongrel dogs and the cells were cultured and expanded before being labeled with DAPI (4’, 6-diamidino-2-phenylindone). The labeled cells were then implanted into the acute myocardial infarct site via the ligated left anterior descending (LAD) coronary artery. Specimens were taken at 2nd, 4th, 8th week after myoblast implantation for histologic and contractile force evaluation, respectively. Results The satellite cells with fluorescence had been observed in the infarct site and also in papi- llary muscle with consistent oriented direction of host myocardium. A portion of the implanted cells had differen- tiated into muscle fibers. Two weeks after implantation, the myocardial contractile force showed no significant difference between the cell implant group and control group. At 4 and 8 week, the contractile force in the cell implant group was better than that in control group. Conclusion The skeletal muscle satellite cells, implanted into infarct myocardium by intracoronary arterial perfusion, could disseminate through the entire infarcted zone with myocardial regeneration and improve the contractile function of the infarcted myocardium.展开更多
Background: Anastatica hierochuntica L. (Brassicaceae) has been claimed to treat various conditions, including complicated childbirth. The principal objective of this research was to provide scientific evidence on the...Background: Anastatica hierochuntica L. (Brassicaceae) has been claimed to treat various conditions, including complicated childbirth. The principal objective of this research was to provide scientific evidence on the contractile effect of the aqueous and hydroethanolic extracts of the whole plant from A. hierochuntica during labor. Method: Qualitative and quantitative methods helped identify and quantify the phytoconstituents in both extracts. The antioxidant activity was studied using four standard methods (ABTS, DPPH, FRAP, and LPO). Results: The inhibitory power of the extracts on pro-inflammatory enzymes such as 15-lipoxygenase and phospholipase A<sub>2</sub> was determined. The contractile effects of the extracts were evaluated using isolated pregnant mice uteri. Steroids, triterpenoids, flavonoids, tannins, coumarins, and reduced compounds were identified in both extracts. The hydroethanolic extract exhibited higher content of hydrolyzable tannins (15.07 ± 0.24 mg tannic acid equivalent/g) than the aqueous decoction (11.8 ± 0.69 mg TAE/g). The extracts demonstrated the ability to scavenge DPPH and ABTS radicals, reduce ferric ions, and inhibit especially lipid peroxidation. No significant difference was noted in the phospholipase inhibition between the extracts and betamethasone. The hydroethanolic extract displayed the most significant anti-lipoxygenase activity with an IC<sub>50</sub> value of 55.82 ± 1.15 μg/mL. The lethal dose (LD<sub>50</sub>) of extracts was estimated to be superior to 2000 mg/kg body weight (bw). The ability of the samples to produce one cm amplitude of contraction at 50% effective concentrations (EC<sub>50</sub>) was 5.33 × 10<sup>−8</sup> ± 0.32 mg/mL for oxytocin, 1.51 ± 0.08 mg/mL for aqueous extract and 3.57 ± 0.61 mg/mL for hydroethanolic extract. Conclusion: These findings could provide evidence for using Anastatica hierochuntica to facilitate childbirth.展开更多
A printable artificial muscle assembled from biomolecular motors,which we have recently developed,showed great potential in overcoming the design limitations of conventional biohybrid robots as a new bioactuator.Chara...A printable artificial muscle assembled from biomolecular motors,which we have recently developed,showed great potential in overcoming the design limitations of conventional biohybrid robots as a new bioactuator.Characterizing its contractility for extending its applicability is important.However,conventional measurement methods are composed of complex operations with poor reproducibility,flexibility,and real-time responsiveness.This study presents a new method for measuring the contractile force generated by artificial muscles.A measurement system was constructed,wherein artificial muscles were patterned by UV laser scanning in an oil-sealed microchamber,and the contractile force was measured in real time using a microforce sensor extended by a 3D-printed microcantilever.The measurement accuracy of the sensor was ensured through calibration and correction.For demonstration purposes,a series of contractile measurements were carried out using the proposed system.The relationship between contractile force and the dimensions of the activation space of the artificial muscles,as well as the tensile properties of the contracted muscle chain were evaluated.The results will help characterize the contractile properties of the artificial muscle and lay the foundations for its further application in biohybrid robotics.展开更多
Emerging heart-on-a-chip platforms are promising approaches to establish cardiac cell/tissue models in vitro for research on cardiac physiology,disease modeling and drug cardiotoxicity as well as for therapeutic disco...Emerging heart-on-a-chip platforms are promising approaches to establish cardiac cell/tissue models in vitro for research on cardiac physiology,disease modeling and drug cardiotoxicity as well as for therapeutic discovery.Challenges still exist in obtaining the complete capability of in situ sensing to fully evaluate the complex functional properties of cardiac cell/tissue models.Changes to contractile strength(contractility)and beating regularity(rhythm)are particularly important to generate accurate,predictive models.Developing new platforms and technologies to assess the contractile functions of in vitro cardiac models is essential to provide information on cell/tissue physiologies,drug-induced inotropic responses,and the mechanisms of cardiac diseases.In this review,we discuss recent advances in biosensing platforms for the measurement of contractile functions of in vitro cardiac models,including single cardiomyocytes,2D monolayers of cardiomyocytes,and 3D cardiac tissues.The characteristics and performance of current platforms are reviewed in terms of sensing principles,measured parameters,performance,cell sources,cell/tissue model configurations,advantages,and limitations.In addition,we highlight applications of these platforms and relevant discoveries in fundamental investigations,drug testing,and disease modeling.Furthermore,challenges and future outlooks of heart-on-a-chip platforms for in vitro measurement of cardiac functional properties are discussed.展开更多
Acute respiratory failure is the most frequent indication for the application of mechanical ventilation. As commonly used in clinical settings, lung protective strategies and recruitment manoeuvres are applications o...Acute respiratory failure is the most frequent indication for the application of mechanical ventilation. As commonly used in clinical settings, lung protective strategies and recruitment manoeuvres are applications of higher than normal airway pressure to open the collapsed alveoli and prevent lung atelectasis caused by minimal vital ventilation. Under those conditions, we pay more attention to the lung injury and circulatory failure,展开更多
Purpose This study aimed to compare the effects of ground and treadmill running on energy metabolism and muscle con-tractile properties,providing a basis for the general public to choose running venues.Methods Ten mal...Purpose This study aimed to compare the effects of ground and treadmill running on energy metabolism and muscle con-tractile properties,providing a basis for the general public to choose running venues.Methods Ten male college students(age,20.10±1.53 years;height,176.20±5.49 cm;weight,72.14±8.25 kg;body fat percent,12.41%±4.65%)were recruited in this study.Energy expenditure(EE)was measured using the accelerometer(GT9X)combined with specific estimation equations.Average heart rate(HR)was measured using a heart rate band(Polar).Muscle contractile properties were assessed by measuring muscle displacement(Dm)and contraction velocity(Vc)using tensiomyography(TMG-S1).Blood glucose(Glu)and lactate(Lac)were measured by portable devices(eB-G and Lactate Scout).The running speed was 9 km/h and the duration was 25 min.Two-way ANOVA(protocol×time)was used to analyze the effect of running protocols on energy metabolism and muscle contractile properties.Results EE of treadmill running was significantly higher than EE of ground running(protocol main effect,P<0.001),and HR of treadmill running was significantly higher than that of ground running in the first testing time(protocol simple effect,P=0.026;protocol×time interaction P=0.043).The decrease in Dm of the rectus femoris after treadmill running was significantly higher than that of ground running(protocol main effect,P=0.009).The interaction of different running protocols and testing times on Lac was significant(P=0.025),but all results of the simple effects analysis were not statisti-cally significant(P>0.05).Conclusion Our study found a difference in energy expenditure between treadmill and ground running at 9 km/h with duration of 25 min.In addition,treadmills are more likely to cause a decrease in muscle displacement distance of the rectus femoris measured after exercise than ground running.Future studies are needed to further investigate whether the differences are induced by internal metabolism or the environmental conditions of running.展开更多
Background： Hemorrhagic shock （HS） results in myocardial contractile dysfunction. Studies showed that 17β-estradiol protects the myocardium against contractile dysfunction. The study investigated the cardioprotect...Background： Hemorrhagic shock （HS） results in myocardial contractile dysfunction. Studies showed that 17β-estradiol protects the myocardium against contractile dysfunction. The study investigated the cardioprotective effects of treatment with 17β-estradiol before resuscitation following 1 h of HS and resuscitation. Methods： Male Sprague-Dawley rats were assigned to 2 sets of experimental protocols： Ex vivo and in vivo treatment and resuscitation. Each set had three experimental groups （n = 6 per group）： Normotensive （N）, HS and resuscitation （HS-R） and HS rats treated with 17β-estradiol （E） and resuscitated （HS-E-R）. Rats were hemorrhaged over 60-rain to reach a mean arterial blood pressure of 40 mmHg. In the ex vivo group, hearts were resuscitated by perfusion in the Langendorff system. In the 17β-estradiol treated group, 17β-estradiol 280 μg/kg was added for the first 5 min. Cardiac function was measured. Left ventricular generated pressure （LVGP） and ＋dP/dt were calculated. In the in vivo group, rats were treated with 17β-estradiol 280 ±g/kg s.c. after 60-rain HS. Resuscitation was performed in vivo by the reinfusion of the shed blood for 30-min to restore normotension. Results： Treatment with 17β-estradiol before resuscitation in ex vivo treated and resuscitated isolated hearts and in the in vivo treated and resuscitated rats following HS improved myocardial contractile function. In the in vivo treated group, LVGP and ＋dP/dt max were significantly higher in 17β-estradiol treated rats compared to the untreated group （LVGP 136.40 ± 6.61 compared to 47.58 ± 17.55, and ＋dP/dt 661.85 ± 49.88 compared to 88.18 ± 0.85）. Treatment with 17β-estradiol improved LVGP following HS. Conclusions： The results indicate that treatment with 17β-estradiol before resuscitation following HS protects the myocardium against dysfunction.展开更多
AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameter...AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameters over time.METHODS: Twenty-one patients after subtotal esophagectomy and 18 healthy volunteers were studied.Complaints were compiled by using a questionnaire, and a symptom score was formed. Synchronous electrogastrography and gastric manometry were performed in the fasting state and postprandially.RESULTS: Eight of the operated patients were symptomfree and 13 had symptoms. The durations of the postoperative periods for the symptomatic (9.1±6.5 mo)and the asymptomatic (28.3±8.8 mo) patients were significantly different. The symptom score correlated negatively with the time that had elapsed since the operation. The percentages of the dominant frequency in the normogastric, bradygastric and tachygastric ranges differed significantly between the controls and the patients.A significant difference was detected between the power ratio of the controls and that of the patients. The occurrence of tachygastria in the symptomatic and the symptom-free patients correlated negatively both with the time that had elapsed and with the symptom score. There was a significant increase in motility index after feeding in the controls, but not in the patients. The contractile activity of the stomach increased both in the controls and in the symptom-free patients. In contrast, in the group of symptomatic patients, the contractile activity decreased postprandially as compared with the fasting state.CONCLUSION: The patients' post-operative complaints and symptoms change during the post-operative period and correlate with the parameters of the myoelectric and contractile activities of the stomach. Tachygastria seems to be the major pathogenetic factor involved in the contractile dysfunction.展开更多
AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In ...AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In each group, fi vetime-lapse movies containing 3 representative bile cana-liculi were taken under phase-contrast microscopy for12 h. The number of bile canalicular contractions andthe intervals between consecutive canalicular contrac-tions were calculated. Furthermore, the effects of TLC onIRHC were examined by transmission electron micros-copy.RESULTS: The bile canalicular contractions were spon-taneous and forceful in the controls. Active vesicularmovement was observed in the pericanalicular region.Immediately after the addition of TLC, the bile canaliculiwere deformed, and canalicular bile was incorporatedinto the vacuoles. The canaliculi were gradually dilated,and canalicular contractions were markedly inhibited byTLC. The vesicular movements became extremely slowin the pericanalicular region. The number of canalicularcontractions significantly decreased in the TLC-treatedgroups, as compared with that in the controls. The timeintervals were prolonged, as the TLC dosage increased,indicating that bile secretion into the canaliculi wasimpaired with TLC. Transmission electron microscopyrevealed the lamellar transformation of the canalicularmembranes in IRHC treated with TLC.CONCLUSION: TLC impairs both the bile canalicularcontractions and the canalicular bile secretion, possiblyby acting directly on the canalicular membranes in TLC-induced cholestasis.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
Acoustic tweezing cytometry(ATC)is a recently developed method for cell mechanics regulation.Tar-geted microbubbles,which are attached to integrins and subsequently the actin cytoskeleton,anchor,amplify and transmit t...Acoustic tweezing cytometry(ATC)is a recently developed method for cell mechanics regulation.Tar-geted microbubbles,which are attached to integrins and subsequently the actin cytoskeleton,anchor,amplify and transmit the mechanical energy in an acoustic field inside the cells,eliciting prominent cy-toskeleton contractile force increases in various cell types.We propose that a mechanochemical con-version mechanism is critical for the high efficiency of ATC to activate cell contractility responses.Our models predict key experimental observations.Moreover,we study the influences of ATC parameters(ul-trasound center frequency,pulse repetition frequency,duty cycle,and acoustic pressure),cell areas,the number of ATC stimuli,and extracellular matrix rigidity on cell contractility responses to ATC.The simu-lation results suggest that it is large molecules,rather than small ions,that facilitate global responses to the local ATC stimulation,and the incorporation of visible stress fiber bundles improves the accuracy of modeling.展开更多
A finite element(FE) model for the numerical control(NC) bending of Ti-3 Al-2.5 V titanium alloy seamless tube is established, considering the variation in the contractile strain ratio(CSR) and elastic modulus(E). The...A finite element(FE) model for the numerical control(NC) bending of Ti-3 Al-2.5 V titanium alloy seamless tube is established, considering the variation in the contractile strain ratio(CSR) and elastic modulus(E). The wall thinning characteristics of Ti-3 Al-2.5 V tube under different geometric and process conditions were investigated. The results showed that the CSR-E variation can change the wall thickness, but has no remarkable effect on the change characteristics. The reasonable parameter ranges are as follows: a bending-radius range not less than 1.5 times the outer diameter, a bend angle up to 180?, and a mandrel extension of 0-3 mm. The friction coefficient between the pressure die and the tube should be in the range of 0.20-0.35, and between the bending die and the tube should be in the range of 0.05-0.15. As long as the performance meets the requirements, the relative push-assistant speed should be as small as possible.展开更多
The number of patients suffering from symptoms associated with gastrointestinal(GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. C...The number of patients suffering from symptoms associated with gastrointestinal(GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. Currently available drugs,which can directly affect gastrointestinal smooth muscle and restore altered smooth muscle contractility to normal,are not satisfactory for treating patients with GI motility disorders. We have recently shown that ERK1/2 and p38MAPK signaling pathways play an important role in the contractile response not only of normal intestinal smooth muscle but also of inflamed intestinal smooth muscle. Here we discuss the possibility that ERK1/2 and p38MAPK signaling pathways represent ideal targets for generation of novel therapeutics for patients with GI motility disorders.展开更多
基金supported by National Natural Science Foundation of China(No.81303076)the Clinical Science and Technology Project of Department of Science and Technology of Jiangsu Province(No.BL2012060)the Eleventh Five-Year Technology Support Project(No.2008BAI51B03)
文摘Sheng-Mai-San(SMS), a well-known Chinese medicinal plant formula, is widely used for the treatment of cardiac diseases characterized by deficiency of Qi and Yin syndrome. A mouse chronic intermittent hypoxia(CIH) model was established to mimic the primary clinical features of deficiency of Qi and Yin syndrome. Mice experienced CIH for 28 days(nadir 7% to peak 8% oxygen, 20 min per day), resulting in left ventricle(LV) dysfunction and structure abnormalities. After administration of SMS(0.55, 1.1, and 5.5 g·kg-1·d-1) for four weeks, improved cardiac function was observed, as indicated by the increase in the ejection fraction from the LV on echocardiography. SMS also preserved the structural integrity of the LV against eccentric hypotrophy, tissue vacuolization, and mitochondrial injury as measured by histology, electron microscopy, and ultrasound assessments. Mechanistically, the antioxidant effects of SMS were demonstrated; SMS was able to suppress mitochondrial apoptosis as indicated by the reduction of several pro-apoptotic factors(Bax, cytochrome c, and cleaved caspase-3) and up-regulation of the anti-apoptosis factor Bcl-2. In conclusion, these results demonstrate that SMS treatment can protect the structure and function of the LV and that the protective effects of this formula are associated with the regulation of the mitochondrial apoptosis pathway.
基金Project supported by the National Natural Science Foundation of China(Nos.11772183 and11832017)
文摘The behavior of large deformations of cellular tissues is usually affected by the local properties of cells and their interactions,resulting in folding which acts as an important role in the embryonic development,as well as growing and spreading of a tumor,which can rapidly promote the stereo complexity of the architecture of the tissues.In the present study,a cylindrical vertex model is constructed to explore the morphology of the tubular cell sheets subject to an embedded contractile ring.It is found that an inner region of the contractile ring in equilibrium will protrude from the tube wall,and it will suddenly collapse when the contractile strength exceeds a threshold,indicating the occurrence of a bifurcation.These results on the effect of embedded contraction in the tubular shell are quite different from the planar cases,which can reveal the importance of the interaction between the geometric and material non-linearity in cylindrical geometry.The dependence of the large deformation on the bending modulus parameters and contraction strength is also analyzed for the cylindrical cell shell.
文摘The incidence of gallstone is higher in patients with diabetes mellitus than in general popula- tion. It is generally attributed to hypomotility and lowered emptying function of the gallblad- der. In this study, we investigate if chronic hy- perglycemia is correlated with reduced contrac- tile function of the bile ducts in rat. Hypergly- cemic rats were induced by streptozotocin-nic-otinamide treatment. Hyperglycemic rats were sacrificed eight months after induction and bile ducts were removed for the subsequent studies. The bile duct contractility of the normal rats is consistently higher than that of the hypergly- cemic rats. The contractities were measured to be 5.5 ± 0.2 mg vs. 4.2 ± 0.1 mg without CCK stimulation, and 5.5 ± 0.3 mg vs. 7.9 ± 0.4 mg with CCK stimulation, respectively for hypergly-cemic and normal rats. There was no significant difference in plasma CCK concentration in hy- perglycemic rats and normal rats. The expres- sion of CCK-A receptor protein in the bile duct tissue was decreased in hyperglycemic rats compared with that of the normal rats, and it may, at least in part, responsible for a reduced contractility. A reduced bile duct motility may cause bile retention, and may be one of the factors predispose to gallstone formation in type 2 diabetes patients, which is characterized with chronic hyperglycemia.
文摘Background Cathepsin S and its endogenous inhibitor cystatin C are implicated in the pathogenesis of atherosclerosis,especially in the plaque destabilization and rupture leading to acute coronary syndrome.However, whether circulating cathepsin S and cystatin C also change in association with coronary plaque morphology is unknown yet. Methods Sprague-Dawley rats were randomly divided into three groups;Sham group,CME group and SB203580 group (n=10 per group).CME rats were produced by injection of 42μm microspheres into the left ventricle with occlusion of the ascending aorta.SB203580,a p38 MAPK inhibitor,was injected into femoral vein after finishing the injection of microspheres in SB203580 group.Left ventricular Ejection Fraction was determined by echocardiography.The level of phosphorylated and total P38 MAPK in myocardium was assessed by Western Blot.Results Left ventricular(LV) Ejection Fraction was depressed at 3 hours and until up to 12 hours in CME group.The increased p38 MAPK activation was observed in CME group.The administration of SB203580 partly inhibited the p38 MAPK activity and preserved cardiac contractile function.Conclusions p38 MAPK is significantly activated by CME and the inhibition of p38 MAPK can partly preserve cardiac contractile function.
文摘It is not certain whether the myocyte contractile function in the heartfailure is normal according to recent some studies,therefore the contractile functionof the myocytes with the heart failure should be studied. The myocyte heart failuremodel was set up by the method of stretching the cultured myocytes,and the myocytes with and without the heart failure were measured the contractile mechanicscharacteristic,the parameters being the maximal contractive velocity of the myocyte(Vmax), the maximal shortening length of myocyte contraction (ΔLmax) and themaximal decrease of the myocyte size during contraction (ΔSmax), by the videoedgedetector system. And then the protein genes (including α-MHC and β-MHC)expression of these myocytes were quantitatively measured by the dot blotting. Thecorrelative and regressive analysis were used to analyze the relationship between themyocyte contractile mechanics characteristic and the contractile protein genes expression level. The results showed that the contractile mechanics parameters,Vmax=41．5±6．0(μm/sec), △Lmax= 10．6±1．9 (% ) and △Smax= 14．3± 2．3 (% ), in themyocytes with the heart failure are statistically significant lower than the normalmyocytes (P<0．01), whose parameters are Vmax=67．9±6．7 (μm/sec), △Lmax=17．7±1．6 (% ) and △Smax=21．5±2．4 (%). The myocyte contractile protein gene (αMHC) expression level in the heart failure myocytes is statistically significant lowerthan that in the normal myocytes,but β-MHC gene expression level is statisticallysignificant higher than the normal myocytes. The α-MllC gene expression level is apositive correlation coefficient with the myocyte contractile mechanics parametersseparately,covering Vmax,△Lmax and △max; but the β- MHC gene expression levelis a negative correlation coefficietn with the myocyte contractile mechanics parameters separately.
基金Supported by the Natural Science Foundation of China(No.81100695)the Japan Society for the Promotion of Science(JSPS)([C] 25462750)
文摘AIM: To investigate the alterations in both structure and contractile responsiveness of ocular ciliary artery(OCA) in spontaneously hypertensive rat(SHR).METHODS: In this experiment, 20-week-old male SHR and Wistar Kyoto rat(WKY) were studied. The heart rate(HR), the blood pressure(BP; the systolic BP and the diastolic BP) of rats with an electronic sphygmomanometer were measured. Vascular morphometry and isometric tension measurement were used to investigate the alterations in structure and contractility of OCA.RESULTS: A general narrowing of OCAs was observed in SHR compared to the control WYK. In SHR, the media of OCAs were thicker, the luminal diameters were smaller, and the media-to-lumen ratios were higher when compared with WKY(P<0.05). The contractions of OCAs evoked by norepinephrine were smaller in SHR compared to control(P<0.05). Then, OCAs were pretreated with iberiotoxin, L-NAME, or indomethacin 30 min before norepinephrineinduced contraction. Iberiotoxin(0.1 μmol/L) has not changed the norepinephrine-induced contractions in OCAs from both groups. However, L-NAME(100 μmol/L) increased the vasoconstrictions, the increased extents were similar in SHR and WKY(P>0.05). Indomethacin(10 μmol/L) decreased the contractions induced by norepinephrine in OCAs from WKY(P<0.05), but did not change those contractions in vessels from SHR(P>0.05).CONCLUSION: Our results demonstrate that the structure and function of OCAs are altered in hypertension. OCAs from SHR are remodeled with decreased lumen diameter and increased media-to-lumen ratio. Moreover, the contractile responsiveness of OCAs from SHR is diminished due to the disruption of vasoconstrictive effect of prostaglandins.
基金Challenging Exploratory Research(16K12864)Grants-in-Aid for Scientific Research(C)(23500539)and(21K12661)from the Japan Society for the Promotion of Science.
文摘While fatty acids play essential roles in the physiology of the myocardium,conventional culture media contain little lipid.We previously revealed that rat neonatal myocardium mainly contains docosahexaenoic(DHA),linoleic(LA),and arachidonic(AA)acids as polyunsaturated fatty acids(PUFAs),and these contents in cultured cardiomyocytes derived from fetal rats were markedly lower than those in the neonatal myocardium.In this study,we first assessed the effects of supplementation of DHA,LA,or AA on the fatty acid contents and the percentage change of contractile area in primarily cultured rat cardiomyocytes.Based on this assessment,we then evaluated the effects of DHA or AA supplementation on mRNA expression and further directly measured the contractile force of cardiomyocytes with the supplementations.This study revealed that percentage change of contractile area was maximized under 20μM DHA or 50μM AA supplementation while LA supplementation did not affect this contraction index,and that a widespread upregulation tendency of the mRNA expression related to differentiation,maturity,fatty acid metabolism,and cell adhesion was seen in the cultured cardiomyocytes with supplementation of DHA or AA.In particular,upregulation of the gene expression of cellular adhesion molecules connexin43 and N-cadherin were remarkable,whereas the effects on differentiation and maturation were less pronounced.Correspondingly,the increase of the percentage change of the contractile area of cardiomyocyte clusters in culture dishes with the supplementations was significant,whereas the enhancement of the contractile force was modest.These results suggest that supplementation of DHA or AA to the fetal cardiomyocyte culture may play effective roles in preventing the de-differentiation of the cardiomyocytes in culture and that the enhancement of the contractile performance may be mainly attributed to the improvement of intercellular connection.
文摘Objective To study the improvement of infarcted myocardial contractile force after autologous skeletal muscle satellite cell implantation via intracoronary arterial perfusion. Methods Skeletal muscle cells were harvested from gluteus max of adult mongrel dogs and the cells were cultured and expanded before being labeled with DAPI (4’, 6-diamidino-2-phenylindone). The labeled cells were then implanted into the acute myocardial infarct site via the ligated left anterior descending (LAD) coronary artery. Specimens were taken at 2nd, 4th, 8th week after myoblast implantation for histologic and contractile force evaluation, respectively. Results The satellite cells with fluorescence had been observed in the infarct site and also in papi- llary muscle with consistent oriented direction of host myocardium. A portion of the implanted cells had differen- tiated into muscle fibers. Two weeks after implantation, the myocardial contractile force showed no significant difference between the cell implant group and control group. At 4 and 8 week, the contractile force in the cell implant group was better than that in control group. Conclusion The skeletal muscle satellite cells, implanted into infarct myocardium by intracoronary arterial perfusion, could disseminate through the entire infarcted zone with myocardial regeneration and improve the contractile function of the infarcted myocardium.
文摘Background: Anastatica hierochuntica L. (Brassicaceae) has been claimed to treat various conditions, including complicated childbirth. The principal objective of this research was to provide scientific evidence on the contractile effect of the aqueous and hydroethanolic extracts of the whole plant from A. hierochuntica during labor. Method: Qualitative and quantitative methods helped identify and quantify the phytoconstituents in both extracts. The antioxidant activity was studied using four standard methods (ABTS, DPPH, FRAP, and LPO). Results: The inhibitory power of the extracts on pro-inflammatory enzymes such as 15-lipoxygenase and phospholipase A<sub>2</sub> was determined. The contractile effects of the extracts were evaluated using isolated pregnant mice uteri. Steroids, triterpenoids, flavonoids, tannins, coumarins, and reduced compounds were identified in both extracts. The hydroethanolic extract exhibited higher content of hydrolyzable tannins (15.07 ± 0.24 mg tannic acid equivalent/g) than the aqueous decoction (11.8 ± 0.69 mg TAE/g). The extracts demonstrated the ability to scavenge DPPH and ABTS radicals, reduce ferric ions, and inhibit especially lipid peroxidation. No significant difference was noted in the phospholipase inhibition between the extracts and betamethasone. The hydroethanolic extract displayed the most significant anti-lipoxygenase activity with an IC<sub>50</sub> value of 55.82 ± 1.15 μg/mL. The lethal dose (LD<sub>50</sub>) of extracts was estimated to be superior to 2000 mg/kg body weight (bw). The ability of the samples to produce one cm amplitude of contraction at 50% effective concentrations (EC<sub>50</sub>) was 5.33 × 10<sup>−8</sup> ± 0.32 mg/mL for oxytocin, 1.51 ± 0.08 mg/mL for aqueous extract and 3.57 ± 0.61 mg/mL for hydroethanolic extract. Conclusion: These findings could provide evidence for using Anastatica hierochuntica to facilitate childbirth.
基金partly funded by KAKENHI(nos.21H05880,21K18700,and 22H04951)New Energy and Industrial Technology Development Organization(NEDO).
文摘A printable artificial muscle assembled from biomolecular motors,which we have recently developed,showed great potential in overcoming the design limitations of conventional biohybrid robots as a new bioactuator.Characterizing its contractility for extending its applicability is important.However,conventional measurement methods are composed of complex operations with poor reproducibility,flexibility,and real-time responsiveness.This study presents a new method for measuring the contractile force generated by artificial muscles.A measurement system was constructed,wherein artificial muscles were patterned by UV laser scanning in an oil-sealed microchamber,and the contractile force was measured in real time using a microforce sensor extended by a 3D-printed microcantilever.The measurement accuracy of the sensor was ensured through calibration and correction.For demonstration purposes,a series of contractile measurements were carried out using the proposed system.The relationship between contractile force and the dimensions of the activation space of the artificial muscles,as well as the tensile properties of the contracted muscle chain were evaluated.The results will help characterize the contractile properties of the artificial muscle and lay the foundations for its further application in biohybrid robotics.
基金The authors acknowledge the Canadian Institutes of Health Research(CIHR)and the Natural Sciences and Engineering Research Council of Canada(NSERC)for financial support through a Collaborative Health Research Projects(CHRP)grant.W.K.D.acknowledges the Ted Rogers Centre for Heart Research Education Fund for a fellowshipN.L.acknowledges the National Natural Science Foundation of China(NSFC)for financial support under Grant 61933008。
文摘Emerging heart-on-a-chip platforms are promising approaches to establish cardiac cell/tissue models in vitro for research on cardiac physiology,disease modeling and drug cardiotoxicity as well as for therapeutic discovery.Challenges still exist in obtaining the complete capability of in situ sensing to fully evaluate the complex functional properties of cardiac cell/tissue models.Changes to contractile strength(contractility)and beating regularity(rhythm)are particularly important to generate accurate,predictive models.Developing new platforms and technologies to assess the contractile functions of in vitro cardiac models is essential to provide information on cell/tissue physiologies,drug-induced inotropic responses,and the mechanisms of cardiac diseases.In this review,we discuss recent advances in biosensing platforms for the measurement of contractile functions of in vitro cardiac models,including single cardiomyocytes,2D monolayers of cardiomyocytes,and 3D cardiac tissues.The characteristics and performance of current platforms are reviewed in terms of sensing principles,measured parameters,performance,cell sources,cell/tissue model configurations,advantages,and limitations.In addition,we highlight applications of these platforms and relevant discoveries in fundamental investigations,drug testing,and disease modeling.Furthermore,challenges and future outlooks of heart-on-a-chip platforms for in vitro measurement of cardiac functional properties are discussed.
基金This research was supported by Doctor’s Science Project Foundation of Liaoning Province (No.20021033), and by Young Science and Development Foundation of Shenyang City (No.2003-48).
文摘Acute respiratory failure is the most frequent indication for the application of mechanical ventilation. As commonly used in clinical settings, lung protective strategies and recruitment manoeuvres are applications of higher than normal airway pressure to open the collapsed alveoli and prevent lung atelectasis caused by minimal vital ventilation. Under those conditions, we pay more attention to the lung injury and circulatory failure,
文摘Purpose This study aimed to compare the effects of ground and treadmill running on energy metabolism and muscle con-tractile properties,providing a basis for the general public to choose running venues.Methods Ten male college students(age,20.10±1.53 years;height,176.20±5.49 cm;weight,72.14±8.25 kg;body fat percent,12.41%±4.65%)were recruited in this study.Energy expenditure(EE)was measured using the accelerometer(GT9X)combined with specific estimation equations.Average heart rate(HR)was measured using a heart rate band(Polar).Muscle contractile properties were assessed by measuring muscle displacement(Dm)and contraction velocity(Vc)using tensiomyography(TMG-S1).Blood glucose(Glu)and lactate(Lac)were measured by portable devices(eB-G and Lactate Scout).The running speed was 9 km/h and the duration was 25 min.Two-way ANOVA(protocol×time)was used to analyze the effect of running protocols on energy metabolism and muscle contractile properties.Results EE of treadmill running was significantly higher than EE of ground running(protocol main effect,P<0.001),and HR of treadmill running was significantly higher than that of ground running in the first testing time(protocol simple effect,P=0.026;protocol×time interaction P=0.043).The decrease in Dm of the rectus femoris after treadmill running was significantly higher than that of ground running(protocol main effect,P=0.009).The interaction of different running protocols and testing times on Lac was significant(P=0.025),but all results of the simple effects analysis were not statisti-cally significant(P>0.05).Conclusion Our study found a difference in energy expenditure between treadmill and ground running at 9 km/h with duration of 25 min.In addition,treadmills are more likely to cause a decrease in muscle displacement distance of the rectus femoris measured after exercise than ground running.Future studies are needed to further investigate whether the differences are induced by internal metabolism or the environmental conditions of running.
文摘Background： Hemorrhagic shock （HS） results in myocardial contractile dysfunction. Studies showed that 17β-estradiol protects the myocardium against contractile dysfunction. The study investigated the cardioprotective effects of treatment with 17β-estradiol before resuscitation following 1 h of HS and resuscitation. Methods： Male Sprague-Dawley rats were assigned to 2 sets of experimental protocols： Ex vivo and in vivo treatment and resuscitation. Each set had three experimental groups （n = 6 per group）： Normotensive （N）, HS and resuscitation （HS-R） and HS rats treated with 17β-estradiol （E） and resuscitated （HS-E-R）. Rats were hemorrhaged over 60-rain to reach a mean arterial blood pressure of 40 mmHg. In the ex vivo group, hearts were resuscitated by perfusion in the Langendorff system. In the 17β-estradiol treated group, 17β-estradiol 280 μg/kg was added for the first 5 min. Cardiac function was measured. Left ventricular generated pressure （LVGP） and ＋dP/dt were calculated. In the in vivo group, rats were treated with 17β-estradiol 280 ±g/kg s.c. after 60-rain HS. Resuscitation was performed in vivo by the reinfusion of the shed blood for 30-min to restore normotension. Results： Treatment with 17β-estradiol before resuscitation in ex vivo treated and resuscitated isolated hearts and in the in vivo treated and resuscitated rats following HS improved myocardial contractile function. In the in vivo treated group, LVGP and ＋dP/dt max were significantly higher in 17β-estradiol treated rats compared to the untreated group （LVGP 136.40 ± 6.61 compared to 47.58 ± 17.55, and ＋dP/dt 661.85 ± 49.88 compared to 88.18 ± 0.85）. Treatment with 17β-estradiol improved LVGP following HS. Conclusions： The results indicate that treatment with 17β-estradiol before resuscitation following HS protects the myocardium against dysfunction.
文摘AIM: To investigate the electric and contractile mechanisms involved in the deranged function of the transposed stomach in relation to the course of the symptoms and the changes in contractile and electrical parameters over time.METHODS: Twenty-one patients after subtotal esophagectomy and 18 healthy volunteers were studied.Complaints were compiled by using a questionnaire, and a symptom score was formed. Synchronous electrogastrography and gastric manometry were performed in the fasting state and postprandially.RESULTS: Eight of the operated patients were symptomfree and 13 had symptoms. The durations of the postoperative periods for the symptomatic (9.1±6.5 mo)and the asymptomatic (28.3±8.8 mo) patients were significantly different. The symptom score correlated negatively with the time that had elapsed since the operation. The percentages of the dominant frequency in the normogastric, bradygastric and tachygastric ranges differed significantly between the controls and the patients.A significant difference was detected between the power ratio of the controls and that of the patients. The occurrence of tachygastria in the symptomatic and the symptom-free patients correlated negatively both with the time that had elapsed and with the symptom score. There was a significant increase in motility index after feeding in the controls, but not in the patients. The contractile activity of the stomach increased both in the controls and in the symptom-free patients. In contrast, in the group of symptomatic patients, the contractile activity decreased postprandially as compared with the fasting state.CONCLUSION: The patients' post-operative complaints and symptoms change during the post-operative period and correlate with the parameters of the myoelectric and contractile activities of the stomach. Tachygastria seems to be the major pathogenetic factor involved in the contractile dysfunction.
文摘AIM: To investigate the effects of taurolithocholate (TLC)on the canalicular motility in isolated rat hepatocyte cou-plets (IRHC).METHODS: TLC was added to IRHC at concentrationsof 10 and 50 μmol/L, respectively. In each group, fi vetime-lapse movies containing 3 representative bile cana-liculi were taken under phase-contrast microscopy for12 h. The number of bile canalicular contractions andthe intervals between consecutive canalicular contrac-tions were calculated. Furthermore, the effects of TLC onIRHC were examined by transmission electron micros-copy.RESULTS: The bile canalicular contractions were spon-taneous and forceful in the controls. Active vesicularmovement was observed in the pericanalicular region.Immediately after the addition of TLC, the bile canaliculiwere deformed, and canalicular bile was incorporatedinto the vacuoles. The canaliculi were gradually dilated,and canalicular contractions were markedly inhibited byTLC. The vesicular movements became extremely slowin the pericanalicular region. The number of canalicularcontractions significantly decreased in the TLC-treatedgroups, as compared with that in the controls. The timeintervals were prolonged, as the TLC dosage increased,indicating that bile secretion into the canaliculi wasimpaired with TLC. Transmission electron microscopyrevealed the lamellar transformation of the canalicularmembranes in IRHC treated with TLC.CONCLUSION: TLC impairs both the bile canalicularcontractions and the canalicular bile secretion, possiblyby acting directly on the canalicular membranes in TLC-induced cholestasis.
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.
基金This work is supported by the National Natural Science Founda-tion of China(Grant No.11874280)the State Key Laboratory of Acoustics,Chinese Academy of Sciences(Grant No.SKLA202211).
文摘Acoustic tweezing cytometry(ATC)is a recently developed method for cell mechanics regulation.Tar-geted microbubbles,which are attached to integrins and subsequently the actin cytoskeleton,anchor,amplify and transmit the mechanical energy in an acoustic field inside the cells,eliciting prominent cy-toskeleton contractile force increases in various cell types.We propose that a mechanochemical con-version mechanism is critical for the high efficiency of ATC to activate cell contractility responses.Our models predict key experimental observations.Moreover,we study the influences of ATC parameters(ul-trasound center frequency,pulse repetition frequency,duty cycle,and acoustic pressure),cell areas,the number of ATC stimuli,and extracellular matrix rigidity on cell contractility responses to ATC.The simu-lation results suggest that it is large molecules,rather than small ions,that facilitate global responses to the local ATC stimulation,and the incorporation of visible stress fiber bundles improves the accuracy of modeling.
基金the China Postdoctoral Science Foundation(No.2016M590677)the National Natural Science Foundation of China(No.51741503)+1 种基金the Fund of the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP201631)the Basic and Advanced Technology Research Program of Henan Province(No.162300410211)
文摘A finite element(FE) model for the numerical control(NC) bending of Ti-3 Al-2.5 V titanium alloy seamless tube is established, considering the variation in the contractile strain ratio(CSR) and elastic modulus(E). The wall thinning characteristics of Ti-3 Al-2.5 V tube under different geometric and process conditions were investigated. The results showed that the CSR-E variation can change the wall thickness, but has no remarkable effect on the change characteristics. The reasonable parameter ranges are as follows: a bending-radius range not less than 1.5 times the outer diameter, a bend angle up to 180?, and a mandrel extension of 0-3 mm. The friction coefficient between the pressure die and the tube should be in the range of 0.20-0.35, and between the bending die and the tube should be in the range of 0.05-0.15. As long as the performance meets the requirements, the relative push-assistant speed should be as small as possible.
基金Supported by the Research Grant from the Canadian Institutes for Health Research,and Partly by an Alberta Innovates-Health Solutions Senior Scholar Award and Canada Research Chair in Smooth Muscle Pathophysiology
文摘The number of patients suffering from symptoms associated with gastrointestinal(GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. Currently available drugs,which can directly affect gastrointestinal smooth muscle and restore altered smooth muscle contractility to normal,are not satisfactory for treating patients with GI motility disorders. We have recently shown that ERK1/2 and p38MAPK signaling pathways play an important role in the contractile response not only of normal intestinal smooth muscle but also of inflamed intestinal smooth muscle. Here we discuss the possibility that ERK1/2 and p38MAPK signaling pathways represent ideal targets for generation of novel therapeutics for patients with GI motility disorders.
