Relationship between the gene polymorphisms of transforming growth factor beta 1 and interleukin 1 beta and primary knee osteoarthritis in Xinjiang Han and Uygur populations / 中国组织工程研究

BACKGROUND:Transforming growth factor β1 (TGF-β1) and interleukin 1β (IL-1β) have been reported to play an important role in the occurrence and development of primary osteoarthritis. OBJECTIVE:To investigate the association between gene polymorphisms of TGF-β1 and IL-1β and primary knee osteoarthritis. METHODS: Han and Uyghur elderly populations in Xinjiang Uygur Autonomous Region, China were surveyed on the prevalence of osteoarthritis, followed by allotted to osteoarthritis and health groups according the symptoms and radiography. Genotyping TGF-β1-509C/T and -1348C/T and IL-1β-511C/T was performed to analyze the relationship between the gene polymorphisms of TGF-β1 and IL-1β and osteoarthritis. RESULTS AND CONCLUSION:Alleles T and C with genotypes CC, CT and TT were detected in both two groups. In the Uygur population, the genotype frequency of TGF-β1-509C/T and IL-1β-511C/T showed significant difference between osteoarthritis and health groups (P < 0.05). In the Han population, the genotype frequency of TGF-β1-1348C/T showed significant difference between two groups (P < 0.05). These results suggest that the Uygur individuals carrying TT genotype of TGF-β1-509C/T and IL-1β-511C/T, and Han people carrying the TT genotype of TGF-β -1348T are more susceptible to osteoarthritis.

Investigation on influence factors of pathogenic bacterial detection results in children lower respiratory tract infections / 国际检验医学杂志

Objective To investigate the distribution characteristics of pathogenic bacteria among different seasons and ages in children lower respiratory tract infection.Methods To retrospectively analyze the results of bacterial culture in pediatric outpatients and inpatients with lower respiratory tract infections in our hospital from September 2014 to August 2015.The pathogenic bacterial detection situation of lower respiratory tract infection among different age groups and different were statistically analyzed.Results A total of 2 809 pathogenic bacterial strains were isolated from 4 629 lower respiratory tract specimens,and detection rate was 60.7%.The pathogenic bacteria distribution was different among different age groups.Haemophilus influenzae (33.3%) ranked the first place in the lower respiratory infection among children aged from 19 d to 7 year old.The detection rates of Haemophilus parainfluenzae,Moraxella catarrhalis and staphylococcus aureus had obvious seasonality,while Streptococcus pneumoniae had no obvious seasonality.Conclusion Pathogenic bacteria causing lower respiratory tract infections in children are different from those in adults,which are affected by age and seasonal change.

Construction and identification of FRET-based MMP3 biosensor / 吉林大学学报(医学版)

Objective:To study the construction of matrix metalloproteinase 3 (MMP3)biosensor vector,and to illuminate the activated process of MMP3 in the living cells.Methods:The ECFP-MMP3-YPet biosensor vector anchored on cellular surface was constructed and identified.The MMP3 biosensor was transfected into the 293T cells.The transfection efficiency was observed 24 h after transfection.The flurorescence resonance energy transfer (FRET )-based MMP3 biosensor was observed by inversion fluorescence microscope. Results:The MMP3 biosensor vector was successfully constructed.The length of MMP3-YPet identified by double enzyme digestion and PCR was about 780 bp.The transfection efficiency of MMP3 biosensor was about 40%,and which was evenly presented in cytoplasm of 293T cells.And the FRET ratio of MMP3 biosensor was decreased after stimulation with uPA on the 293T cells. The FRET ratio reached its minimum about 30 min later. Conclusion:The MMP3 biosensor can sensitively and reliably monitor the MMP3 activation in living cells.

Regression analysis of factors affecting efficacy of arthroscopic treatment for knee osteoarthritis / 局解手术学杂志

Objective To investigate the factors that affecting the efficacy of arthroscopic debridement in the treatment of knee osteoar-thritis. Methods The clinical data of patients with knee osteoarthritis treated with arthroscopic debridement in our hospital from January 2009 to December 2013 was retrospectively analyzed,and the treatment effect was evaluated by Lysholm score. The factors that may affect the efficacy were selected to make a single factor analysis,and then made a multiple logistic regression analysis with the factors which were of sta-tistical significance through single factor analysis. Results Single factor analysis showed that age,course of disease,body mass index,psycho-logical factor,preoperative VAS score,preoperative Kellgren-Lawrence grade,preoperative Lysholm score and postoperative rehabilitation exer-cise were the factors that affected the efficacy of knee arthroscopy in the treatment of knee osteoarthritis,and the difference between the two groups was statistically significant. Further multivariate analysis showed that high body mass index,high preoperative VAS pain score,low Ly-sholm score,high psychological expectations and high preoperative Kellgren-Lawrence grading were expected to be the independent risk fac-tors of knee arthroscopy in the treatment of knee osteoarthritis. Strict compliance with the postoperative rehabilitation exercise was the protect factor. Conclusion High body mass index,high preoperative VAS pain score,low preoperative Lysholm score,high preoperative Kellgren-Lawrence grading,and high psychological expectations were expected to reduce the effect of surgery,while strict compliance with the postoper-ative rehabilitation exercise can improve the curative effect.

Characteristics of pathogens and risk factors of surgical site infection in orthopedic patients in five consecutive years / 中国感染控制杂志

Objective To investigate the incidence of surgical site infection (SSI)in patients undergoing orthopedic surgery,analyze the risk factors,and provide basis for the prevention and control of SSI.Methods All hospitalized orthopedic patients undergoing surgery in a hospital from January 2010 to December 2014 were retrospectively sur-veyed,questionnaires were designed,patients’medical records were reviewed,incidence of SSI was analyzed,risk factors for SSI were analyzed with univariate and logistic regression methods.Results A total of 14 300 orthopedic patients undergoing surgery were investigated,576 (4.03%)patients had SSI,predominantly were superficial inci-sion infection (n=429,74.48%),615 strains of pathogenic bacteria were isolated from 576 patients,mainly were Staphylococcus aureus (n=137,22.28%),Escherichia coli (n=84,13.66%),and Enterobacter cloacae (n=73, 11 .87%).The incidence of SSI decreased year by year in patients undergoing orthopedics surgery(χ2 =24.706,P <0.001);the incidence of SSI in patients with amputation was the highest (22.67%),followed by patients with de-bridement (7.16%);multivariate logistic regression analysis indicated that long duration of operation,long length of hospital stay,underlying diseases,use of implants,contaminated incision,more intraoperative blood loss,irra-tional perioperative use of antimicrobial agents,and without using negative pressure drainage were independent risk factors for SSI in patients undergoing orthopedic surgery.Conclusion The incidence of SSI is high in orthopedic pa-tients undergoing surgery,effective preventive measures should be actively taken according to the related risk factors of SSI,so as to reduce the occurrence of SSI.

Comparison of effect between tranexamic acid versus fibrin sealant after joint arthroplasty:a Meta-analysis / 重庆医学

Objective To compare the effectiveness and safety of tranexamic acid and fibrin sealant in joint arthroplasty . Methods The literatures on the application of tranexamic acid and fibrin sealant in joint arthroplasty were retrieved from PubMed , Embase ,Cochrane Library ,CNKI and other internet databases .Two reviewers independently screened the literatures according to the inclusion and exclusion standard .The RevMan 5 .2 software was adopted to conduct the statistical analysis on the extracted da‐ta .Results Four randomized controlled trials(RCTs) and 2 retrospective experiments were included ,involving 449 patients .The meta analysis results showed that tranexamic acid and fibrin sealant had no statistically significant difference in total blood loss[MD= -192 .24 ,95% CI(-496 .16 ,111 .69) ,P=0 .22] and hemoglobin loss amount[MD= -0 .49 ,95% CI(-1 .19 ,0 .20) ,P=0 .16] , had statistically significant difference in the blood transfusion rate[OR=0 .30 ,95% CI(0 .18 ,0 .52) ,P<0 .01] ,and had no statisti‐cally significant difference in the postoperative complications[OR=1 .20 ,95% CI(0 .36 ,3 .99) ,P=0 .76] .Conclusion Tranexamic acid is more effective than fibrin sealant of controlling postoperative transfusion rate in joint arthroplasty .

The modified bacterial two-hybrid system / 生物工程学报

Bacterial two-hybrid system is a newly developed method for studying protein-protein interactions. However, in our studies of the interaction of regulatory proteins in Streptomyces, it was found that the bacterial two-hybrid system is not sensitive enough by the blue-and-white selection on X-gal plate. To overcome this drawback, the reason of false positive clone was firstly determined, which was the disturbance of other direct or indirect regulation on lacZ promoter. Then the disturbance was diluted by introducing multicopy lacZ promoter, which drive another reporter gene gfp. By such design, the sensitivity of the modified bacterial two-hybrid system was significantly inproved and the two different reporters also help to decrease the rate of the false positive clones. Further the evaluation of the modifiedd bacterial two-hybrid system indicated that the sensitivity was significantly improved.

Construction and identification of urokinase-type plasminogen activator biosensor plasmid / 吉林大学学报(医学版)

Objective To construct the eukaryotic expression vector urokinase-type plasminogen activator (uPA) biosensor which was the composition of the fusion protein enhanced cyan fluorescent protein-uPA (substrate)-yellow fluorescent protein variant (ECFP-uPA substrate-linker-YPet).Methods By the template Src-biosensor, the YPet primers were designed by Primer Premier 5.0 software,and the restriction enzyme sites,uPA substrate gene sequence and linker were added in its 5′ end. With the intermediate vector pDMTM-18T, an eukaryotic expression vector which contained a fusion protein of ECFP-uPA substrate-linker-YPet was constructed by genetic engineering.Then the uPA biosensor was transfected into 293T cells.The transfection efficiency and expression of fusion proteins were observed after 24 h.Fluorescence resonance energy transfer (FRET)was observed by the inversion fluorescence microscope and measured by the MetaFlour FRET 4.6 software. Results The uPA biosensor vector was confirmed by the fragment of PCR and double restriction enzyme digestion.The transfection efficiency was nearly 40%.The immunofluorescence detection results displayed that uPA biosensor fusion protein expressed in the 293T cells membrane and the FRET of uPA biosensor in the living 293T cells was observed after incubation with the recombinant human uPA (rhuPA).Conclusion uPA biosensor is successfully constructed and it could be used as a molecular probe to study the temporal and spatial variation of uPA in living cells.

The epidemiological characteristics of Salmonella in children with infectious diarrhea in Zhuhai City from 2009 to 2014 / 国际检验医学杂志

Objective To investigate epidemiological characteristics of Salmonella infection in children with infectious diarrhea in Zhuhai City from 2009 to 2014 .Methods Isolation ,culturing ,biochemical identification and serotyping of Salmonella were carried out in strains isolated from stool specimens of 4 395 children with infectious diarrhea in inpatient and outpatient settings in Zhuhai Municipal Maternal and Child Healthcare Hospital from 2009 to 2014 ,and data were statistically analysed .Results A total of 546 strains of Salmonella was isolated(the overall isolation rate was 12 .42% ) and 30 serotypes were identified .Among children with Salmonella infection ,those under 3 years old accounted for 93 .22% .There was no statistically significant difference of isolation rate between male and female children with infectious diarrhea(P<0 .05) .June and July were peak period of Salmonella infection ,and the isolation rate was 16 .40% and 16 .09% respectively .Isolates of Salmonella typhimurium ,Salmonella enteritidis and Salmonella stanley account for 50 .92% ,13 .55% and 10 .26% respectively ,which were dominant serotypes .Conclusion Salmonella is the main pathogenic bacteria in children with infectious diarrhea in Zhuhai area ,and Salmonella typhimurium is the main serotype .The infec‐tion of Salmonella might be correlated with children′s age and climate change .

Analysis of locking plate in the treatment of proximal humerus fractures / 重庆医学

Objective To evaluate the clinical and radiological results of locking plate for treatment of proximal humerus frac‐tures and the efficacy of anatomical healing of tuberosities .Methods A total of 57 patients with proximal humerus fractures were treated with locking‐plate from July 2008 to March 2012 .A standardized radiological evaluation was conducted .Patients were divid‐ed into two groups :group A (anatomical healing of tuberosities) with 31 cases and group B (without anatomical healing of tuberosi‐ties) with 26 cases .Clinical assessment was performed using the Neer rating scale .Results Considering the entire sample ,the mean Neer score was 87 .96 ± 5 .06 points ,the excellent rate was 94 .74℅ .Comparing these parameters in the two groups ,group A was significant higher in the Neer scores and the range of movement than that of group B (P0 .05) .Conclusion the locing plate for treatment of complex proximal humerus fractures has a high subjective satisfaction rate .A good functional result depends on anatomical reestablishment of proximal humerus anatomy , particularly the healing of the greater tuberosity .

Application of polyetheretherketone cages and titanium cages combined with pedicle screw fixation operation in lumbar degenerative disease / 局解手术学杂志

Objective To explore the clinical efficacy of polyetheretherketone( PEEK) cages and titanium cages combined with pedicle screw fixation operation in treatment of lumbar degenerative disease,and provide reference for clinic. Methods The data of 50 patients with lumbar degenerative disease in our hospital from March 2011 to March 2013 were retrospectively analyzed. All patients were treated with pos-terior decompression,bone graft and transpedicular screw internal fixation,according to the different cages,they were divided into PEEK group and titanium group. The PEEK group with 25 patients used polyetheretherketone cages,and the titanium group with 25 patients used titanium cages. The JOA scores of patient before surgery,1 month,6 months and 1 year after surgery between two groups were recorded and compared. The ROM of fusion levels and adjacent segment of patients before and after operation between two groups were compared. Results There was no statistical significance of difference in JOA score,Oswestry score and fusion rate between two groups(P>0. 05). There were statistical significance of differences intervertebral disc height change between 2 groups(P<0. 05). The ROM of fusion levels and adjacent segment of patients in PEEK group was better than those in titanium group(P<0. 05). Conclusion The polyetheretherketone cages combined with pedicle screw fixation operation have a good effect in the treatment of patients with lumbar degenerative disease,especially in matter of lumbar spinal motion and intervertebral height lost.

Progress in transcriptional studies / 生物工程学报

Gene expression exhibits temporal and spatial patterns to response environmental changes and growth cycle. Gene expression is under strict control at different levels among which control at transcription level is the predominant mode, especially in prokaryotes. In this review, we summarized the new developments of methods used in transcriptional studies, including modifications and improvements of the classic methods, such as gel-shift assay, DNA foot printing, and in vivo reporter system. In addition, we introduced examples to apply new methods, such as surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) to characterize protein-DNA, ligand-protein, and ligand-protein-DNA interactions. The collection of these methods and their application could guide and accelerate relevant studies.

Randomized,controlled clinical trial comparison of sodium hyaluronate versus celecoxib in knee osteoarthritis patients / 实用医学杂志

Objective To compare the effects of sodium hyaluronate (SH) and celecoxib (CO) administration on the treatment of knee osteoarthritis (OA) and to investigate their influences on levels of uPA and MMP-3 in synovial fluid. Methods One hundred and thirty-six knee osteoarthritis (OA) patients from January 2010 to October 2011 were randomly enrolled into two groups: the SH group and the CO group. In the SH group, patients were injected with 2 mL sodium hyaluronate intra articulation once a week for 5 weeks. In the CO group , patients were given oral administration of celecoxib daily at a dosage of 200 mg for 5 weeks. Before and at 1 ,6 months after treatment, Lequesne′s index and VAS-pain were detected to assess the clinical results of these two drugs. The levels of uPA and MMP-3 in synovial fluid were measured by using ELISA assay. Results All patients were followed up for 6 months to 12 months. The Lequesne′s index and VAS-pain score were lowered at 1 and 6 moths after treatment in both the SH group and the CO group(P0.05). Dramatic reduction of the levels of uPA and MMP-3 in synovial fluid were observed in the SH group after treatment(P0.05). Conclusion The redueced levels of uPA and MMP-3 in synovial fluid after treatment of sodium hyaluronate may contribute to its longer-lasting effect than that of celecoxib. Therefore , the combination of sodium hyaluronate with celecoxib may lead to better therapeutic effect on OA patients.

The expression and significance of MMP3 in synovium of knee joint of different stage in osteoarthritis patients / 实用医学杂志

Objective To investigate the expression and significance of MMP-3 in knee joint synovium of different stage in osteoarthritis (OA) patients. Methods MMP-3 protein were detected by immunohistochemical method in knee synovial tissues from 90 OA patients (the OA group) and OA group was divided into 3 subgroups according to Kellgren and LawrenceX-ray diagnosing standards: the gradeⅠ(n = 30), gradeⅡ (n = 30) and grade Ⅲ subgroups (n = 30). 30 patients were enrolled as control group. Immunohistochemistry was used to detect the expression of MMP-3 protein in the tissue. Results The expression level of MMP-3 protein in OA group was significantly higher that in the normal synovium (P < 0.05). There existed significant difference in the expression of MMP-3 protein between the grade Ⅲ subgroup and the gradeⅠ, or Ⅱsubgroups (P < 0.05). The expression of MMP-3 protein related positively to the severity of OA (r = 0.912, P < 0.05). Conclusion The expression of MMP-3 protein related closely to the pathogenic mechanism of OA. It may serve as an important indicator of early diagnosis and the activity of OA.

Analysis of carrying status and drug susceptibility of Streptococcus agalactiae in genital tract of pregnant women / 国际检验医学杂志

Objective To understand the carrying status and drug resistance of streptococcus agalactiae in the genital tract of pregnant women.Methods The vaginal discharge from pregnant women was collected for conducting the bacterial culture.The iso-lated streptococcus agalactiae was performed the identification and the drugs susceptibility test by the VITEK 2 fully automatice bacterial identification analyzer.Results Among 1 042 samples,streptococcus agalactiae was isolated in 6 cases with the separation rate of 5.4%.The drug sensitivity test showed the Streptococcus agalactiae was highly sensitive to penicillin,cefazolin,vancomycin, linezolid and nitrofurantoin.The intermediate strains or drug resistant strains were not found.The sensitive rate to levofloxacin, moxifloxacin and clindamycin,erythromycin,tetracycline were 84.0%,84.0%,71.4%,39.3% and 8.9% respectively.Conclusion The carrying rate of streptococcus agalactiae in pregnant women is not high in our hospital.Penicillin and cefazolin should be as the drug of first choice for therapy and the clincal and laboratory nould payattention to detection of streptococcus agalactiae in pregnant women.

Antibiotic resistance of the Haemophilus inf luenzae strains isolated from respiratory tract in children / 中国感染与化疗杂志

Objective To investigate the antibiotic resistance of Haemophilus influenzae isolates collected from the children with respiratory tract infection for rational use of antibiotics in clinical practice .Methods The H .influenzae strains were isolated from children and subjected to antimicrobial susceptibility testing by Kirby-Bauer method .Nitrocefin disc test was used to detect the production of beta-lactamases .WHONET 5 .6 software was used to analyze the susceptibility data .Results A totalof1256strainsof H.influenzaewereisolated.About37.8% ,65.5% and16.5% ofthe1256strainsof H.influenzae were resistant to ampicillin ,trimethoprim-sulfamethoxazole ,and ampicillin-sulbactam ,respectively .Less than 10 .0% of these strains were resistant to any other antibiotics tested .Beta-lactamase was produced in 33 .5% of the 1 256 strains of H . influenzae .Conclusions The H . influenzae strains in this study are mainly resistant ampicillin and trimethoprim-sulfamethoxazole .About 80 .0% of these H . influenzae strains were still susceptible to cefaclor ,ampicillin-sulbactam , cefixime ,ceftazidime ,azithromycin ,ciprofloxacin ,meropenem and rifampin .The primary mechanism of ampicillin resistance in Haemophilus is production of beta-lactamases .

Analysis of Salmonella infection in 6 417 cases of infectious diarrhea / 国际检验医学杂志

Objective To understand the status quo of Salmonella infection in the patients with infectious diarrhea in Zhongshan city .Methods The fecal samples collected from 6 417 outpatients or inpatients with infection diarrhea in our hospital from January 2010 to December 2013 were performed the Salmonella culture ,isolation and identification and at the same time the serological clas-sification and the pulsed-field gel electrophoresis (PFGE) were performed .Results Among 6 417 samples ,460 strains of Salmonel-la were detected with the isolation rate of 7 .17% .Salmonella infection was dominated by children infection .The Salmonella infec-tion rate in children aged less than 1 years was 52 .4% (241 cases) ,followed by children aged 1- < 3 years ,which was 36 .7% (169 cases) .In the serological classification ,the most of detected Salmonella was salmonella typhimurium 46 .1% ,accounting for 46 .1% , Stanley salmonella accounting for 13 .5% and Salmonella enteritidis accounting for 8 .7% .The PFGE homology analysis showed that in the XbaI enzyme digestion spectral band ,26 PFGE band types had 100% homology .Conclusion Salmonella is one of the main pathogenic bacteria causing diarrhea and serious impact on health ,which is worthy of clinicians to pay attention to .

Expression and significance of matrix metalloproteinase 14 in synovial tissue and syrovial fluid of osteoarthritis / 重庆医学

Objective To evaluate the expression and clinical significance of matrix metalloproteinase 14(MMP-14) in osteoar-thritis(OA) patients in synovium and synovial fluid of knee joint .Methods Semi-quantitative RT-PCR were used to detect the ex-pression of MMP-14 mRNA in 32 case of OA (experimental group)and 26 non-OA patients(control group)synovium ;protein level expression of MMP-14 in synovial fluid were analyzed by ELISA .Results The expression of MMP-14 mRNA in experimental group synovium of knee joint was significantly increased compared with control group (P<0 .05);but the protein level of MMP-14 was low in experimental group synovial fluid compared with control group (P<0 .05) .Conclusion The expression of MMP-14 is increased in OA patients synovium and maybe promote the progress of OA directly ;the protein level of MMP-14 is decreased in OA synovial fluid ,indicated the function of MMP-14 in OA synoviocyte indirectly .

Optimized sample preparation for metabolome studies on Streptomyces coelicolor / 生物工程学报

Streptomycetes produce many antibiotics and are important model microorgansims for scientific research and antibiotic production. Metabolomics is an emerging technological platform to analyze low molecular weight metabolites in a given organism qualitatively and quantitatively. Compared to other Omics platform, metabolomics has greater advantage in monitoring metabolic flux distribution and thus identifying key metabolites related to target metabolic pathway. The present work aims at establishing a rapid, accurate sample preparation protocol for metabolomics analysis in streptomycetes. In the present work, several sample preparation steps, including cell quenching time, cell separation method, conditions for metabolite extraction and metabolite derivatization were optimized. Then, the metabolic profiles of Streptomyces coelicolor during different growth stages were analyzed by GC-MS. The optimal sample preparation conditions were as follows: time of low-temperature quenching 4 min, cell separation by fast filtration, time of freeze-thaw 45 s/3 min and the conditions of metabolite derivatization at 40 degrees C for 90 min. By using this optimized protocol, 103 metabolites were finally identified from a sample of S. coelicolor, which distribute in central metabolic pathways (glycolysis, pentose phosphate pathway and citrate cycle), amino acid, fatty acid, nucleotide metabolic pathways, etc. By comparing the temporal profiles of these metabolites, the amino acid and fatty acid metabolic pathways were found to stay at a high level during stationary phase, therefore, these pathways may play an important role during the transition between the primary and secondary metabolism. An optimized protocol of sample preparation was established and applied for metabolomics analysis of S. coelicolor, 103 metabolites were identified. The temporal profiles of metabolites reveal amino acid and fatty acid metabolic pathways may play an important role in the transition from primary to secondary metabolism in S. coelicolor.

Study of TGF-β/Smad3 signal pathway using the technology of flurorescence resonance energy transfer / 生物医学工程学杂志

The transforming growth factor-β1 (TGF-β1)/Smad3 signal pathway is related to mutiple physiological and pathological generation mechanism of human being. Up to date, however, the spacial and time information on the phosphorylated Smad3 is still unclear. In this study, the process of Smad3 phosphorylation was observed under the physiological state in the living cells. Firstly, the ECFP-Smad3-Citrine (Smad3 biosensor) fusion protein expression vector was constructed and identified. Then the Smad3 biosensor was transfected into 293T cells. The transfection efficiency and the expressions of fusion proteins were observed in 24 hours. Thirdly, Smad3 biosensor flurorescence resonance energy transfer (FRET) was observed with the inversion fluorescence microscope and measured by the MetaFlour FRET 4. 6 software. Smad3 biosensor transfection efficiency was nearly 40% and the fusion protein was seen under the fluorescence microscope. The FRET ratio of Smad3 biosensor in living 293T cells was decreased after 10 minutes incubation with the ligand of TGF-β1. The period of decreasing CFP and enhancing Citrine signals was about 300 seconds. With the technology of FRET, the TGF-β1/Smad3 signal pathway could be real time monitored dynamically under the physiological condition in living cells.