Biomedical subjects

Y Zeng

Publications and source records attributed to Y Zeng.

At least 19 recordsLinked to original sources

PubMed2001

Stressed apoptotic tumor cells express heat shock proteins and elicit tumor-specific immunity.

In attempting to develop effective anticancer immunotherapies, the relative ability of apoptotic cells to induce an immune response remains an important but controversial consideration. A novel gene-transfer approach was used by which rapid induction of pure apoptosis can be selectively achieved in a transfected tumor cell population following exposure to a semisynthetic dimerizing ligand, AP20187. Inoculation of BALB/c mice with apoptotic and viable 12B1-D1 leukemia cells, at a 12:1 ratio subcutaneously, led to early tumor growth. Heat stress up-regulated the expression of membrane heat shock proteins (HSP72 and HSP60) on apoptotic 12B1-D1 cells, and stressed apoptotic cells were capable of generating a T-cell-mediated specific antitumor response. Pulsing of stressed apoptotic leukemia cells onto syngeneic dendritic cells resulted largely in rejection of coinjected viable 12B1-D1 cells. Mice rejecting the primary 12B1-D1 inoculum were immune to the same but not to a different leukemia challenge. Our findings indicate that tumor immunogenicity is dependent on whether cells are stressed before apoptosis induction and suggest that the immune system is capable of distinguishing between stressed and nonstressed cells undergoing programmed cell death. (Blood. 2001;97:3505-3512)

Animals↗

PubMed2001

Regional characteristics of sulfur and lead isotope ratios in the atmosphere at several Chinese urban sites.

Sulfur and lead isotope ratios in the atmosphere were measured at several selected sites (Harbin, Changchun, Dalian, Waliguan, Shanghai, Nanjing, Guiyang) in China and Tsukuba (Japan), to reveal regional sources characteristics over Eastern Asia. Average S isotope ratios for SO2 and sulfate in the atmosphere in China were close to those of the coals used in each region, indicating a considerable contribution of coal combustion to the sulfur compounds in the atmosphere. Most northern cities had around 5% sulfur isotope ratio, while Guiyang, a southwestern city in China, showed a considerably lower sulfur isotope ratio (about -3%) because of the unusually light sulfur isotope ratio of coals in this region. These were considerably different from the value (-1.4%) for Tsukuba (Japan). Lead isotope ratios also suggested that coal combustion considerably contributed to atmospheric lead in some cases in China. At the same time, influences by the emission of Chinese lead ores were also observed in northern cities. Seasonal variations of both sulfur and lead isotope ratios indicated the existence of a certain amount of industrial sources other than coal combustion. In addition, fractionation effect between SO2 and sulfate showed a seasonal tendency (high in winter (0-6%) and low in summer (-1-3%)), suggesting the oxidation pathway of SO2 changed seasonally.

Air Pollution↗

PubMed2001

Accumulation of caveolin in the endoplasmic reticulum redirects the protein to lipid storage droplets.

Caveolin-1 is normally localized in plasma membrane caveolae and the Golgi apparatus in mammalian cells. We found three treatments that redirected the protein to lipid storage droplets, identified by staining with the lipophilic dye Nile red and the marker protein ADRP. Caveolin-1 was targeted to the droplets when linked to the ER-retrieval sequence, KKSL, generating Cav-KKSL. Cav-DeltaN2, an internal deletion mutant, also accumulated in the droplets, as well as in a Golgi-like structure. Third, incubation of cells with brefeldin A caused caveolin-1 to accumulate in the droplets. This localization persisted after drug washout, showing that caveolin-1 was transported out of the droplets slowly or not at all. Some overexpressed caveolin-2 was also present in lipid droplets. Experimental reduction of cellular cholesteryl ester by 80% did not prevent targeting of Cav-KKSL to the droplets. Cav-KKSL expression did not grossly alter cellular triacylglyceride or cholesteryl levels, although droplet morphology was affected in some cells. These data suggest that accumulation of caveolin-1 to unusually high levels in the ER causes targeting to lipid droplets, and that mechanisms must exist to ensure the rapid exit of newly synthesized caveolin-1 from the ER to avoid this fate.

Amino Acid Sequence↗

PubMed2001

Cloning and functional expression of a degradation-resistant novel isoform of p27Kip1.

p27(Kip1) is an inhibitor of cyclin-dependent kinases. It has been implicated as having a role in the induction of growth arrest at the G(1) phase of the cell cycle in response to anti-mitogenic signals such as cell contact and serum starvation. Proteasome-mediated degradation plays an important role in the rapid inactivation of p27(Kip1), causing quiescent cells to re-enter the cell cycle. Although the existence of a second isoform has been suggested, no such isoform was isolated. Through screening of a cDNA library derived from growth-arrested confluent porcine endothelial cells, we obtained clones for a novel isoform of p27(Kip1) in addition to the original isoform. The novel isoform differed from the original isoform at the C-terminus. The tissue-specific expression of the original and novel isoforms was demonstrated at the mRNA and protein levels. An in vitro degradation assay demonstrated this novel isoform to be resistant to proteasome-mediated destruction. The expression as a fusion protein with green fluorescent protein revealed this isoform to be targeted to the nucleus by a bipartite nuclear-localization signal with a C-terminal part different from that of the original isoform. The expression of the novel isoform caused the growth arrest of HeLa cells and an accumulation of cells in the G(0)/G(1) phase, and this effect was similar to that seen with the original isoform. The present study suggests that the novel isoform functions as a negative regulator of the cell cycle, and may play a distinct role. The novel isoform was named p27(Kip1R) because of its resistance to degradation.

Alternative Splicing↗

PubMed2001

Dendritic-cell-peptide immunization provides immunoprotection against bcr-abl-positive leukemia in mice.

Chronic myelogenous leukemia (CML) is a clonal disorder characterized by proliferation of cells that possess the bcr-abl fusion gene resulting in the production of one of two possible chimeric 210-kDa tyrosine kinase proteins. Since these chimeric proteins are expressed only in leukemic cells they have the potential to serve as tumor-specific antigens for cytotoxic T lymphocytes (CTL). Using the 12B1 murine leukemia cell line, derived by retroviral transformation of BALB/c bone marrow cells with the bcr-abl (b3a2) fusion gene, we have demonstrated that intravenous inoculation of 12B1 cells into BALB/c mice results in a disseminated acute leukemia analogous to human CML in blast crisis. Histological sections of liver and spleen and polymerase chain reaction analysis of peripheral blood, bone marrow, liver, spleen and lymph nodes confirmed the presence of bcr-abl+ leukemia cells in these murine tissues, while Western blot data demonstrated the expression of the fusion protein in 12B1 cells. Immunization of mice with dendritic cells (DC) loaded with the synthetic bcr-abl chimeric nonapeptide, GFKQSSKAL, led to a 150 times higher frequency of bcr-abl-specific CTL precursors in the spleen than in mice immunized with peptide alone. In vitro re-stimulation of DC-peptide-primed splenocytes resulted in substantial secretion of interferon gamma and augmented cytolytic activity against 12B1 targets. Finally, vaccination with peptide-loaded DC significantly prolonged survival of BALB/c mice that were challenged with 12B1 leukemia. The capacity to generate bcr-abl-specific CTL in vivo by DC-based immunization may have clinical implications in the treatment of CML.

Animals↗

PubMed2001

The studies of hemoglobinopathies and thalassemia in China--the experiences in Shanghai Institute of Medical Genetics.

BACKGROUND: In the past two decades, a large-scale survey of hemoglobinopathies and thalassemia was carried out in mainland China, involving nearly one million people in 28 provinces. The incidences of hemoglobin (Hb) variants, alpha-thalassemia and beta-thalassemia were 0.33%, 2.64% and 0.66%, respectively. The chemical structural analysis identified 67 Hb variants. Among them, 20 are new variants. The analysis of the alpha-globin gene organization in 111 HbH patients showed 76 cases (68.5%) were of the deletion type, 8 had Hb Constant Spring and the other cases were of non-deletion type. The results of the molecular characterization of more than 200 beta-thalassemia alleles showed that the most common types of beta-thalassemia mutations in China are CD 41/42 (-4 bp), IVS-II-nt.654 C-->T, CD 17 A-->T, CD 71/72 (+A) and -28 A-->G. METHODS: To explore the simple method for molecular diagnosis of beta-thalassemia, multiplex allele-specific amplification (MAS-PCR) was used that could simultaneously detect the above five common types of beta-thalassemia mutations. RESULTS: Based on the molecular analysis of beta-thalassemia intermedia, beta-thalassemia homozygotes or compound heterozygotes combined with alpha-thalassemia, as well as the conjunctive abnormalities of beta-thalassemia heterozygote with triplicated haplotype of alpha-globin genes, were the most common cause of thalassemia intermedia in China. We also used the RT-PCR quantitation method to show that the most common beta-thalassemia allele, IVS-II-nt.654 C-->T, still produced a small amount (about 15%) of normally spliced beta-globin mRNA, therefore, causing beta+-thalassemia. In clinical trials of hydroxyurea (HU) treatment for beta-thalassemia patients, we found that HU may enhance the expression of the beta-globin gene in some patients, leading to an alleviation of clinical symptoms. In the studies of the reversal of aberrant splicing of IVS-II-nt.654 C-->T allele by the antisense approach, we constructed a mammalian expression vector that can produce an antisense RNA targeting against the aberrant splice sites of IVS-II-nt.654 C-->T pre-mRNA. CONCLUSIONS: The results indicated that the antisense RNA produced from the vector could efficiently suppress the aberrant splicing pattern and restore the correct splicing pathway in vitro and in vivo, leading to the improvement of globin chain biosynthesis in thalassemia cells.

China↗

PubMed2001

A comparison of biomechanical properties between human and porcine cornea.

Due to the difficulty in obtaining human corneas, pig corneas are often substituted as models for cornea research. The purpose of this study is to find the similarities and differences in the biomechanical properties between human and porcine corneas. Uniaxial tests were conducted using an Instron apparatus to determine their tensile strength, stress-strain relationship, and stress-relaxation properties. The tensile strength and stress-strain relation were very similar but significant differences between the two tissues were observed in the stress-relaxation relationship. Under the same stretch ratio lambda=1.5, porcine cornea relaxed much more than human cornea. If tensile strength and the stress-strain relation are the only mechanical factors to be investigated, porcine cornea can be used as a substitute model for human cornea research. However, when stress relaxation is a factor, porcine corneas cannot be used as an appropriate model for human corneas in mechanical property studies. It is very difficult to get enough specimens of human cornea, so we did the experiments for stress-strain relationship at a specific value of strain rate (corresponding to the velocity of loading 10mm/min), and for stress relaxation at a specific stretch ratio lambda=1.5.

Animals↗

PubMed2001

Gene therapy restores vision in a canine model of childhood blindness.

The relationship between the neurosensory photoreceptors and the adjacent retinal pigment epithelium (RPE) controls not only normal retinal function, but also the pathogenesis of hereditary retinal degenerations. The molecular bases for both primary photoreceptor and RPE diseases that cause blindness have been identified. Gene therapy has been used successfully to slow degeneration in rodent models of primary photoreceptor diseases, but efficacy of gene therapy directed at photoreceptors and RPE in a large-animal model of human disease has not been reported. Here we study one of the most clinically severe retinal degenerations, Leber congenital amaurosis (LCA). LCA causes near total blindness in infancy and can result from mutations in RPE65 (LCA, type II; MIM 180069 and 204100). A naturally occurring animal model, the RPE65-/- dog, suffers from early and severe visual impairment similar to that seen in human LCA. We used a recombinant adeno-associated virus (AAV) carrying wild-type RPE65 (AAV-RPE65) to test the efficacy of gene therapy in this model. Our results indicate that visual function was restored in this large animal model of childhood blindness.

Animals↗

PubMed2001

The R region found in the human foamy virus long terminal repeat is critical for both Gag and Pol protein expression.

It has been suggested that sequences located within the 5' noncoding region of human foamy virus (HFV) are critical for expression of the viral Gag and Pol structural proteins. Here, we identify a discrete approximately 151-nucleotide sequence, located within the R region of the HFV long terminal repeat, that activates HFV Gag and Pol expression when present in the 5' noncoding region but that is inactive when inverted or when placed in the 3' noncoding region. Sequences that are critical for the expression of both Gag and Pol include not only the 5' splice site positioned at +51 in the R region, which is used to generate the spliced pol mRNA, but also intronic R sequences located well 3' to this splice site. Analysis of total cellular gag and pol mRNA expression demonstrates that deletion of the R region has little effect on gag mRNA levels but that R deletions that would be predicted to leave the pol 5' splice site intact nevertheless inhibit the production of the spliced pol mRNA. Gag expression can be largely rescued by the introduction of an intron into the 5' noncoding sequence in place of the R region but not by an intron or any one of several distinct retroviral nuclear RNA export sequences inserted into the mRNA 3' noncoding sequence. Neither the R element nor the introduced 5' intron markedly affects the cytoplasmic level of HFV gag mRNA. The poor translational utilization of these cytoplasmic mRNAs when the R region is not present in cis also extended to a cat indicator gene linked to an internal ribosome entry site introduced into the 3' noncoding region. Together these data imply that the HFV R region acts in the nucleus to modify the cytoplasmic fate of target HFV mRNA. The close similarity between the role of the HFV R region revealed in this study and previous data (M. Butsch, S. Hull, Y. Wang, T. M. Roberts, and K. Boris-Lawrie, J. Virol. 73:4847--4855, 1999) demonstrating a critical role for the R region in activating gene expression in the unrelated retrovirus spleen necrosis virus suggests that several distinct retrovirus families may utilize a common yet novel mechanism for the posttranscriptional activation of viral structural protein expression.

Gene Expression Regulation, Viral↗

PubMed2001

Identification of a vibrational frequency corresponding to H-atom translocation in hypericin.

Using time-resolved infrared spectroscopy, ab initio quantum mechanical calculations and synthetic organic chemistry a region in the infrared spectrum of triplet hypericin has been found between 1400 and 1500 cm-1 corresponding to the translocation of the hydrogen atom between the enol and the keto oxygens, O...H...O. This result is discussed in the context of the photophysics of hypericin and of eventual measurements to observe directly the excited-state H-atom transfer.

Anthracenes↗

PubMed2001

The genetic events of HPV-immortalized esophageal epithelium cells.

We studied cytogenesis, telomere and telomerase, and c-myc, ras, bcl-2, and p53 genes of cells in the progressive process of immortal epithelial cells from embryonic esophagus induced by human papillomavirus (HPV). The SHEE cell line, established by us, consist of immortalized epithelial cells from the embryonic esophagus induced by genes E6E7 of HPV type 18. It was in initial malignant transformation when cultivated over 60 passages without co-carcinogens. Cells of the 10th, 31st, and 60th passages were represented in the progressive process within the immortal period. In these three stages of the cell line, the modal number of chromosome and karyotypes were analyzed. The telomere length was assayed by Southern blot methods, and the telomerase activity was analyzed by hTR and hTERT assay. C-myc, p53, bcl-2, ras genes were assayed by the multi-PCR method. The morphology of the 10th passage cells exhibited good differentiation, the 60th passage cells were relatively poorly differentiated, and the 31st passage cells differentiated in two distinct ways. The growth characteristics of the 31st and 60th passage cells were weakened at contact-inhibition and anchorage-dependent growth. Karyotypes of three cell passages belonged to hyperdiploid and hypotriploid with abnormal chromosomes +1, +3, +7, +9, +17, +18; del(1)(p32); der(4), t(4;?)(q31;?); der(5),t(5;?)(q31;?); der(13),t(13;13)(p11;q11) and others. Bimodal distribution of chromosomes with more aberrant chromosomes appeared in the 31st and 60th passage cells. Telomere length sharply shortened from normal fetal esophagus to the 10th and 31st passage step by step, but was stable from the 31st to the 60th passage and the telomerase activities measured were expressed at late two passages. p53 mutant was positive in three passages, c-myc was positive in the 31st and the 60th passage K-ras only in the last. The results reveal that changes of chromosomes, telomere length, telomerase activity and certain gene expressions are important events of HPV-immortalized esophageal epithelium cells. All of these changes occurred in dynamic progressive process. This cell line may be useful for the elucidation of the genetic mechanism of cellular immortalization.

Cell Line, Transformed↗

PubMed2001

A comparative study of telomerase activity and malignant phenotype in multistage carcinogenesis of esophageal epithelial cells induced by human papillomavirus.

To examine certain characteristics of multistep carcinogenesis, we studied telomerase activity and malignant phenotypes in the immortal, premalignant and malignant stages of esophageal epithelial cells induced by HPV. An immortalized human fetal esophageal epithelial cell line (SHEE) was induced by E6E7 genes of human papillomavirus (HPV) type 18. Cells in the 10th passage, (SHEE10), 31st passage (SHEE31), 61st passage (SHEE61) and SHEE61A which were selected and expanded from anchorage-independent growth colonies of SHEE61, were examined as follows: cell morphology by electron-microscopy; the cell cycle by flow cytometry, telomerase activity by TRAP assay, tumorigenic detection including anchorage-independent growth by soft agar culture and tumor formation by inoculating cells into SCID and nude mice, and detection of HPV18 E6E7 oncoprotein by Western blot. The morphology of the SHEE10 cells exhibited good differentiation, the SHEE60 and SHEE61A cells were relatively poorly differentiated, and the SHEE31 cells were differentiated in two distinct ways. The telomerase was activated in SHEE31, SHEE61 and SHEE61A, but not in SHEE10 cells. SHEE61 and SHEE61A cells were weakened in contact-inhibition and increased in anchorage-independent growth. Inoculated into SCID and nude mice, the cells of the earlier two passages could not develop tumors; the SHEE61 developed one tumor in four SCID mice, but not in nude mice, and the SHEE61A cells developed tumors in both strains of immunodeficient mice. HPV18 E6E7 DNA detection by Western blotting was positive in all cell passages. In the process of carcinogenesis by HPV, the cells of SHEE31 are in an immortalized state with telomerase activity. The fact that SHEE61 cells remained immortalized and also demonstrated anchorage-independent growth, reveals premalignant character; the cells of SHEE61A exhibited malignant transformation with tumor formation in mice. The results revealed that the telomerase activity, anchorage-independent growth and tumor formation in nude mice are the indicators for immortalization, premalignancy and malignancy, respectively.

Animals↗

PubMed2001

The effect of fluid shear stress on ICAM-1 expression of rat brain microvascular endothelial cells.

Intercellular adhesion molecule-1 (ICAM-1) is an adherence molecule that is an important factor in many pathophysiological processes such as atherosclerosis, thrombosis and inflammation. It is secretion of endothelial cells by a variety of biochemical stimulations. But hemodynamic forces can also induce various functional changes in vascular endothelium. Some researches have proved that shear stress can modulate the expression of ICAM-1. But most of them examine the regulation of expression of ICAM-1 in human umbilical vein endothelial cells. There is no detail on the effect of shear stress (SS) on ICAM-1 expression of microvascular endothelial cells (RBMECs). In this experiment, we use cultured rat brain microvascular endothelial cells (RBMECs). By using the parallel plate flow chamber method, we give two magnitudes of lamminar shear stresses (0.2 dyn/cm2, 0.4 dyn/cm2) for different perieods of time on the slides of cells. Immunostaining method and image analysis shows a specific upregulation in ICAM-1 expression on RBMECs, which is different from endothelial cells of other species or vascular beds. Expression of ICAM-1 is increased 0.5h after the onset of SS, and reached its highest level 4h after onset of SS, then declines after that. The effect is time-dependent, not force magnitude-dependent. Endothelial cell surface expression of ICAM-1 in the supernatants of RBMECs exposed to SS was not modified excluding the possibility that RBMECs exposed to SS synthesize factors that upregulate ICAM-1. The experiment data are relevant to the current understanding of basic mechanisms that explain the signal transudation pathway occurring inside the endothelial cells under the effect of SS.

Animals↗

PubMed2001

[Gene diagnosis of facioscapulohumeral muscular dystrophy].

OBJECTIVE: Perform gene diagnosis for Chinese facioscapulohumeral muscular dystrophy(FSHD). METHODS: Digest genome DNA with restriction enzymes EcoR I only and EcoR I associated with Bln I. Use 0.6% agarose gel electrophoresis and Southern blotting hybridization with probe P13E11. RESULTS: For FSHD patients, the sizes of EcoR I + Bln I/P13E11 DNA fragments ranged from 15kb to 33kb. For normal controls, they were over 41kb. Two presymptomatic patients were found. CONCLUSION: It is feasible to perform gene diagnosis and presymptomatic diagnosis for most Chinese FSHD patients by Southern blotting hybridization with probe P13E11, following double digestion of genome DNA with restriction enzymes EcoR I and Bln I.

Adult↗

PubMed2001

[Expression property of adhesive molecule ICAM-1 on vitro-cultured pulmonary microvascular endothelial cells under the stimuli of asthmatic serum].

It has been recognized only in the past 15 years that the major pathological mechanism of asthma is inflammation, which has a hallmark of focal leukocyte extravasation. The different recruitment behaviors of inflammatory cells depend on the expression of specific adhesive molecules on both leukocytes and endothelial cells (EC). Intercellular cellular adhesion molecule-1(ICAM-1) plays a major role. In the previous detailed in-vivo study of asthmatic models, we have proved the significant pathological increase of both the leukocyte-endothelium adhesion phenomenon and the ICAM-1 expression in the tissues of asthmatic lung. It may be due to an ICAM-1 accumulation on the microvascular endothelial cells and thus an enhancement of adhesion force during the course of disease. In this study, endothelial cells were obtained from rats by mechanical isolation of lung tissues and in vitro culture on glass. Confluent endothelial cells were incubated with serum collected from rat blood of normal and asthmatic models and were used for in vitro study of endothelial cell adhesion. The effect of pathological serum stimulation was examined on the expression of ICAM-1 of the pulmonary microvascular endothelial cells (PMEC). The expression of ICAM-1 on PMEC was measured by indirect immuno-fluorescence with flow cytometry. We found that the surface expression of ICAM-1 was obviously increased on serum-incubated EC as compared with that on the culture solution-incubated one, and that asthmatic serum increased the expression of ICAM-1 on EC to a peak in 4 hours and then decreased it rapidly, the expression level remained the same in the whole course when EC was treated with culture solution or normal serum.

Animals↗

PubMed2001

[Structure and function of pancreatic microcirculation].

To gain an insight into the relationship between structure and function in pancreatic microcirculation, observations were carried out in 9 corpse, 30 monkeys, 24 dogs, 62 Wistar rats and 24 rabbits by the use of scanning electron microscopy and light microscopy with the technique of retaining microcirculatory dynamic and tissular information in the static specimens, and/or by intravital fluorescence microscopy with FITC-labeled erythrocytes. The results showed: there were two capillary beds destined for the endocrine and exocrine parts of pancreas between the intralobular arteriole and venule; the blood of pancreatic portal circulation flowed from the endocrine to the exocrine part; each pancreatic lobule was supplied by a single centrally located intralobular artery and there was no anastomosis between the intralobular arterioles or any of their branches, so they were end arteries; the physiological blood flow was about 1.18 +/- 0.05 nl/min per capillary with stable capillary perfusion pattern; a profound decreased functional capillary density and capillary perfusion was observed in the early phase of acute pancreatitis. These results suggest that pancreatic lobule is a structured and functional basic unit of pancreatic microcirculation, insulo-acinar portal circulation represents the basic feature of the pancreatic microcirculation, and the intralobular arteriole, being an end artery, forms the anatomical basis of the pancreatic microcirculatory disturbance during acute pancreatitis.

Adult↗

PubMed2001

[Therapeutic potential of recombinant adenovirus expressing p53 in hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the effects of the recombinant adenoviral vector Ad-p53 on the biological behavior of hepatocellular carcinoma (HCC) cells in vitro and in vivo. METHODS: With recombinant adenoviral vector expressing WT-p53 (Ad-p53), p53 gene was transfected into the HCC cell line, PLC/PRF/5. The cytotoxicities of Ad-p53 to cells were measured by MTT assay. Cell growth properties and cell cycle patterns were assessed with flow cytometry. The animal model was developed by injecting HCC cells into the dorsum of nude mice. Ad-p53 was injected intratumorally. The animals were killed, and then excised tumors were weighed and analyzed for p53 and p21 protein expression using western blot assay. RESULTS: The introduction of exogenous wild-type p53 resulted in the inhibition of cell growth, high G2/M ratio and cell apoptosis, and low S ratio in PLC/PRF/5. The expression of both p53 and p21 proteins was upregulated in the cells. CONCLUSIONS: Replication-deficient adenoviral vector expressing WT-p53 may be useful for gene therapy of HCC.

Adenoviridae↗

PubMed2001

Mechanosensitive channel currents recorded in rat microvascular endothelial cells with whole-cell mode.

Using the whole-cell patch-clamp technique, we recorded delayed outward currents in rat brain microvascular endothelial cells (BRMECs), which were nearly completely inhibited by 20 mmol/L extracellular TEA-Cl and 5 mM extracellular CsCl. Whole-cell currents were elicited under voltage clamp condition by 2100 ms depolarizing voltage pulses applied every 7 s between -100 to 90 mV in 10 mV increment from a holding potential of -100 mV. The currents were defined as delayed rectified K+ currents (IKv), which were inhibited in a concentration-dependent manner by bath application of TEA-Cl, with an IC50 approximately 2.0 mM, similar to that reported on IKv in other preparations. In the present of mechanical force, outward currents were increased in amplitude as compared with controls. These mechanical force induced currents were also defined as IKv, which are different from previous described mechanosensitive currents with characteristic of inward rectifier.

Animals↗