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T F Liu

Publications and source records attributed to T F Liu.

At least 19 recordsLinked to original sources
PubMed2001

PDZ domain protein GIPC interacts with the cytoplasmic tail of melanosomal membrane protein gp75 (tyrosinase-related protein-1).

Tyrosinase and tyrosinase-related proteins (TRPs) are a family of melanosomal membrane proteins involved in mammalian pigmentation. Whereas the melanogenic functions of TRPs are localized in their amino-terminal domains that reside within the lumen of melanosomes, the sorting and targeting of these proteins to melanosomes is mediated by signals in their cytoplasmic domains. To identify proteins that interact with the cytoplasmic tail of gp75 (TRP-1), the most abundant melanosomal membrane protein, we performed yeast two-hybrid screening of a melanocyte cDNA library. Here, we show that the cytoplasmic domain of gp75 interacts with a PDZ domain-containing protein. The gp75-interacting protein is identical to GIPC, an RGS (regulator of G protein signaling)/GAIP-interacting protein, and to SEMCAP-1, a transmembrane semaphorin-binding protein. Carboxyl-terminal amino acid residues, Ser-Val-Val, of gp75 are necessary and sufficient for interaction of gp75 with the single PDZ domain in GIPC. Although endogenous and transfected GIPCs bind efficiently to transiently expressed gp75, only a small amount of GIPC is found associated with gp75 at steady state. Using a strategy to selectively synchronize the biosynthesis of endogenous gp75, we demonstrate that only newly synthesized gp75 associates with GIPC, primarily in the juxtanuclear Golgi region. Our data suggest that GIPC/SEMCAP-1 plays a role in biosynthetic sorting of proteins, specifically gp75, to melanosomes.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Copper(II) complexes with N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine: synthesis, characterization, DNA-binding thermodynamical and kinetic studies.

Copper(II) complexes (Cu-L, L=N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine) were synthesized and characterized by elemental analyses, IR spectra and conductance measurement. The interaction of the copper(II) complex with calf thymus DNA was studied by means of UV melting experiments, fluorescence spectra and circular dichroic spectra. Using ethidium bromide as a fluorescence probe, the binding mode of the complexes Cu-L with calf-thymus DNA was studied spectroscopically. The results indicate that the complexes Cu-L perhaps interact with calf-thymus DNA by both intercalative and covalent binding. Kinetics of binding of the cupric complexes to DNA was studied for the first time using ethidium bromide as a fluorescence probe with stopped-flow spectrophotometer under pseudo-first-order condition. The stronger binding of two steps in the process of the complexes Cu-L interacting with DNA was observed, and the probable interaction process was discussed in detail. The corresponding k(obs) and E(a) of binding to DNA (where k(obs) is the observed pseudo-first-order rate constant, E(a) is the observed energy of activation) were obtained.

Amines↗
PubMed2001

Calcium-activated potassium current in single Novikoff cell.

The electrophysiological properties of the hemichannels of the gap junction in a single Novikoff cell was studied using patch-clamp whole-cell recording techniques. During the experiments, a transient outward current (peak current, Ip) was found to be evoked by the increment of depolarized pulses. Ip was voltage-dependent and could be inhibited partly by CsCl and tetraethylammonium (TEA), but was blocked completely by quinidine. When the intracellular free Ca2+ concentration ([Ca2+]i) was increased, the amplitude of Ip was enhanced. Adding 10 mmol/l EGTA in the pipette solution, Ip disappeared. When the cells were bathed in symmetrical high-K+ solution, Ip also completely disappeared. These results suggest that Ip is a calcium-activated potassium current, although it cannot be blocked by apamin.

Animals↗
PubMed2001

Effect of tetramethyl pyrazine on L-type calcium channel in rat ventricular myocytes.

To elucidate possible ionic mechanisms of antimyocardial ischemia and antiarrythmia of tetramethyl pyrazine (TP), we studied L-type Ca2+ currents (I(Ca.L)) in adult rat ventricular myocytes using the whole-cell patch-clamp technique. The results showed: (i) under physiological conditions, 0.25 mmol/L TP decreased amplitude of I(Ca.L) to 60.6% and this inhibition was increased with increasing concentration of TP. ID50 was 0.20 mmol/L. (ii) The Ca2+-antagonistic effect of TP was voltage-dependent. A marked negative shift of the steady-state inactivation curve was observed with long (10 s) conditioning prepulses, but not with short (350 ms) ones. (iii) The time course of inhibition during TP treatment was increased with an increase in drug concentration, and recovery from TP-induced inactivation of I(Ca.L) was slower than in control cases. (iv) Tonic block and use-dependent block with TP treatment, which was induced by increasing the frequency of stimulation, occurred. We suggest that TP inhibits the I(Ca.L) mainly by binding to inactivated Ca2+ channels. The high affinity of TP for the inactivated state of I(Ca.L) may play an important role in developing therapies for pathological conditions.

Animals↗
PubMed2000

The impact of overall treatment time on outcomes in radiation therapy for non-small cell lung cancer.

PURPOSE: A retrospective study was carried out to evaluate the impact of overall treatment time (OTT) on the results of radiation therapy for non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: From Jan. 1990 to Dec. 1996, 256 patients with stages I-IIIb NSCLC entered this analysis. All patients received definitive radiotherapy. Biologically effective dose (BED) was used to standardize the irradiation effects. The correlation between OTT and local progression-free survival was analyzed by linear-regression and Cox proportional hazard models. The prognostic variables for survival and distant metastasis were also briefly studied. RESULTS: OTT had been shortened in 64 patients because of an accelerated hyperfractioned irradiation, while OTT was prolonged i n 114 patients due to interruptions of irradiation courses. The main ca uses of interruption were machine breakdown or delayed preparations of c errobend block for boost fields (55%), holidays (11%) and treatment toxi city and side effects (34%). Patients tre ated with prolonged OTT (> 45 days) had significant poorer local progression-free survival than whom with OTT of </=45 days, 1, 3 and 5 year actuarial local progression-free survivals being 49, 17 and 15% for the former, and 74, 35 and 25% for the latter, respectively (P<0.001). BED-T that contained the factor of OTT correlated directly to local controls, which implied that BED-T represented radiobiological effects accurately, in other words, OTT had played a role in determining the radiobiological effects. Linear-regression on 103 cases treated with BED of 80-85 Gy(10) showed that 3 year local progression-free survival decreased by 9% per week with prolongation of OTT, or vice versa it increased by 9% per week with shortening OTT in an OTT range of 30-76 days. Cox multivariate analyses confirmed that OTT was an independent prognostic factor for local controls. CONCLUSION: OTT may have played an important role in determining local controls in radiotherapy for NSCLC. One should always keep in mind to make the OTT as short as possible, provided the patients can tolerate it, and to reduce irradiation interruptions for whatever reasons to a minimum.

Adult↗
PubMed2000

Synthesis, characterization and cytotoxicity of lanthanum(III) complexes with novel 1,10-phenanthroline-2,9-bis-alpha-amino acid conjugates.

Eight lanthanum(III) complexes with novel 1,10-phenanthroline-2,9-bis-alpha-amino acid conjugates were synthesized and characterized by elemental analyses, IR, MS, 1H-NMR, thermal analysis and conductance measurement. All lanthanum(III) complexes and the corresponding soluble ligand in water have been assayed for antitumor activity in vitro against HL-60 (human leukocytoma) cells, HCT-8 (human coloadenocarcinoma) cells, BGC-823 (human stomach carcinoma) cells, BeL-7402 (human liver carcinoma) cells and KB (human nasopharyngeal carcinoma) cells. The results show that several complexes have relative activity against different cell lines. In particular, the complexes La(L2) and La(L5) show relatively high activity against the BeL-7402 cell line. Moreover, they are slightly more effective than cisplatin. DNA binding studies indicate that the complex La(L2) possibly interacts with calf thymus DNA by both intercalative and covalent binding.

Amino Acids↗
PubMed1999

Impaired production of IL-12 in systemic lupus erythematosus. III: deficient IL-12 p40 gene expression and cross-regulation of IL-12, IL-10 and IFN-gamma gene expression.

Interleukin 12 (IL-12) is a heterodimer comprising p35 and p40 subunits which are encoded and regulated separately. The authors previously demonstrated deficient IL-12 production in SLE which correlates negatively with disease activity. The present study was designed to determine whether deficiency of IL-12 and excess production of IL-10 and IL-6 in systemic lupus erythematosus (SLE) are due to aberrant regulation at the gene level. Using semiquantitative RT-PCR assay, it was shown that constitutive expression of IL-12 p35 gene is somewhat impaired in SLE compared with controls and that IL-12 p40 mRNA, which was present at low levels in controls, was undetectable in unstimulated SLE peripheral blood mononuclear cells (PBMC). Gene expression of IL-12 p35 and p40 was significantly increased in response to SAC, with significantly lower SAC-induced expression of p40 in SLE patients than controls. SAC-stimulated IL-12 p35 and p40 mRNAs were significantly augmented by interferon gamma (IFN-gamma). Exogenous IL-12 or IFN-gamma significantly inhibited IL-10 gene expression, without affecting IL-6 mRNA or other proinflammatory cytokine mRNA levels. These observations were further confirmed by studies of protein production at the single cell level using ELISPOT assay. Downregulation of IL-12 p40 expression appears to be the cause of IL12 p70 deficiency in SLE. If this defect could be repaired, normalization of IL-12 and IFN-gamma production should reduce excessive IL-10 and prevent pathology.

Cells, Cultured↗
PubMed1998

Impaired production of IL-12 in systemic lupus erythematosus. I. Excessive production of IL-10 suppresses production of IL-12 by monocytes.

Interleukin 12 (IL-12) plays a crucial role in defensive immune responses, modulation of cytokine production and is involved in the pathogenesis of some autoimmune diseases. The authors investigated whether decreased in vitro production of IL-12 occurs in systemic lupus erythematosus (SLE), in which the cytokine secreting pattern is predominantly type 2. IL-12 production by SLE peripheral blood mononuclear cells (PBMC) was significantly impaired compared with normal PBMC, and this was not due to decreased numbers of monocytes. After depletion of non-adherent cells from PBMC, monocytes of SLE patients produced significantly less IL-12 than those of controls, but IL-12 levels in SLE and control non-adherent cells supernatants were not significantly different. Exogenous recombinant (r)IL-10 strongly inhibited IL-12 production by both SLE and normal PBMC and anti-IL-10 neutralizing antibody significantly reversed the IL-12 deficiency of SLE PBMC and SLE monocytes, while not affecting normal PBMC. Recombinant interferon gamma (rIFN-gamma) considerably enhanced IL-12 production in both SLE and normal PBMC, but it did not significantly reverse the inhibitory effect of rIL-10 on IL-12 production. IL-12 production was significantly lower in patients with active SLE than those in remission. These results suggest that SLE monocytes may be deficient in IL-12 production and that this is secondary to abnormal production of various cytokines, especially excessive production of IL-10.

B-Lymphocytes↗
PubMed1998

Impaired production of IL-12 in system lupus erythematosus. II: IL-12 production in vitro is correlated negatively with serum IL-10, positively with serum IFN-gamma and negatively with disease activity in SLE.

Interleukin 12 (IL-12) is a key cytokine in regulating type 1 or type 2 cytokine production and in determining the nature of immune responses. Our previous studies demonstrated that its production was significantly impaired in systemic lupus erythematosus (SLE) patients and this deficient IL-12 production was mainly mediated by excessive endogenous IL-10. The present study was designed to further reveal the relationships of in vitro IL-12 production with abnormalities of in vivo cytokine synthesis and disease activity in SLE. Experimental results showed that IL-12 production in vitro was inversely correlated with serum IL-10 level, anti-ds DNA antibody level and SLE disease activity index (DAI), but positively correlated with serum interferon gamma (IFN-gamma) level, with which serum IL-10 correlated negatively. Data also showed that serum IL-10 was significantly higher than that of controls and closely correlated with anti-ds DNA antibody level and SLEDAI. The study confirms that deficient IL-12 production in SLE patients is associated with in vivo abnormalities of cytokine production, especially with increased IL-10 production.

Adult↗
PubMed1997

Hyperfractionated accelerated radiation therapy for non-small cell lung cancer: clinical phase I/II trial.

PURPOSE: In an attempt to improve local control and survival of nonsmall cell lung cancer (NSCLC), hyperfractionated accelerated radiation therapy (HART) was carried out as a clinical phase I/II trial. METHODS AND MATERIALS: HART was delivered by 1.1 Gy/fraction, three fractions per day with intervals of 4 h and five treatment days per week. The clinical tumors were irradiated to 74.3 Gy (72.6-75.9)/66-69 fx, 33 days (29-40) (not corrected for lung density), and the subclinical lesions, to 50.0 Gy (48.4-50.6)/44-46 fx, 33 days (29-40). Sixty-nine patients with NSCLC were enrolled in this study. Nine patients were withdrawn from the study during HART due to different reasons. Sixty patients formed the study for outcome analyses. They were 57 males and 3 females with median age of 61 years (21-77). There were 41 cases of squamous cell carcinoma, 15 cases of adenocarcinoma, and 4 cases of large cell carcinoma. Overall, favorable patients (KPS > or = 70, weight loss < 5% and Stages I, II, IIIa) accounted for 73% (44 of 60) of all patients. Forty-four patients (73%) received adjuvant chemotherapy (DDP + VP16) with median cycles of 1.8 before and/or after HART. In order to compare the outcome of HART with conventional irradiation, 50 NSCLC patients treated by conventional fractionated irradiation (CFI) during the same period were chosen as the basis to evaluate relative effects of HART. They derived from the control group of another clinical trial of hyperfractionated irradiation for NSCLC in the same department. They received median tumor dose of 63.9 Gy (62.8-65.0)/34 fx (32-36), 48 days (45-53). RESULTS: 1. Acute and late complications: (a) In HART, 87% of patients (52 cases) developed acute radiation esophagitis: Grade 1-2, 46 cases (77%) and Grade 3, 6 cases (10%), at 2.5 weeks (2-3.5 weeks) after HART began. Five patients with Grade 3 esophagitis had their HART interrupted for <7 days. In CFI, esophagitis was much less (44%,p < 0.05) with 38% of Grade 1-2 and 6% of Grade 3. (b) In HART, acute pulmonary symptoms (RTOG Grade 1-2) occurred in 17% (10 cases), and acute radiation pneumonitis (Grade 3), in 8% (5 cases), while in CFI, they were 24% and 2% (p > 0.05), respectively. Late lung fibrosis (RTOG Grade 1-2) appeared in 20% (12 cases), whereas 18% in CFI (p > 0.05). (c), No other severe acute or late complications have been observed so far in HART. 2. Immediate response. In HART, 20% of patients (12 cases) achieved CR, 60% (36 cases), PR and 20% (12 cases), NR or PD. In CFI, the above three percentages were 10, 28, and 62%, respectively (p < 0.001). 3. Follow-up. The 1-, 2-, and 3-year actuarial survivals were 72, 47, and 28% for HART, and 60, 18, and 6% for CFI, respectively (p < 0.001). Better local control was seen in HART than in CFI with 1-, 2-, and 3-year local control rates being 71, 44, 29%, and 60, 20, and 5%, respectively (p = 0.001). Distant metastases developed less in HART than in CFI. The 1-, 2-, and 3-year distant metastasis rates were 23, 36, and 50% in HART, but 30, 48, and 80% in CFI (p = 0.021). CONCLUSION: 1. HART could be tolerated by most of the favorable NSCLC patients. The predominant complication was acute esophagitis. No other severe acute or late complications have been observed so far. 2. HART resulted in better survivals and local controls, and less distant metastases than CFI.

Adenocarcinoma↗
PubMed1997

The ionic mechanisms of early after depolarization in mouse ventricular myocytes: the role of IK1.

The occurrence of early after depolarization (EAD) in single mouse ventricular myocytes was observed and its ionic mechanisms were studied using the patch clamp technique. Under treatment with perfusion of Tyrode's solution containing 3 mM KCl and 3 mM CsCl, 3/6 cases exhibited EAD, while with 3 mM KCl or 3 mM CsCl alone, EAD was not induced. The background steady-state current-voltage (I-V) curves of the myocytes showed no negative slope, i.e., the slope in the range of 50 mV positive to the reversal potential was virtually flat and stayed at a low current level. Under perfusion of 3 mM KCl and 3 mM CsCl, the outward current in the above region decreased nearly to 0: in the myocytes which exhibited EAD, a net inward current (crossover) was displayed in the same region, which was abolished by 10 microM TTX and 10 microM nifedipine. The results of whole-cell inward rectifier current I-V curves were similar to the above background steady-state I-V curves. In mouse ventricular myocytes, transient outward current was very strong with a peak current density of 63 +/- 19 pA/pF, whereas low K+ and Cs+ had no significant effect. 11/30 cases showed obvious delayed rectifier current, but the tail current recorded by envelope method was relatively weak (1.19 +/- 0.35 pA/pF) and insensitive to CsCl or changing of the KCl concentration. The results suggest that under treatment with low K+ and Cs+, the inhibition of inward rectifier current is the basis of the formation of second plateau, while Na and Ca currents contribute to the generation of triggered bursts.

Animals↗
PubMed1997

Inhibitory effects of 12-O-tetradecanoylphorbol-13-acetate on dye leakage from single Novikoff cells and on dye transfer between reaggregated cell pairs.

The inhibitory effects of 12-O-tetradeconylphorbol-13-acetate (TPA) on the Lucifer Yellow leakage in single (nondissociated and dissociated) Novikoff cells in the presence of ethyleneglycotetraacetic acid (EGTA) and transfer between reaggregated cell pairs were investigated. Under treatment with TPA, single Novikoff cells showed inhibition of the dye leakage in the presence of EGTA, especially after 60-min treatment. There were only slight differences between nondissociated and dissociated cells in these experiments. The dye transfer in reaggregated cell pairs were significantly inhibited after 30-min treatment with TPA. In pretreatment with TPA during the recovery period of reaggregation the dye transfer in cell pairs was completely blocked. It was suggested that TPA blocks the assembly of gap junction, while it had no remarkable effect on gating mechanism of the hemichannels.

Animals↗
PubMed1996

Cancer risks among iron and steel workers in Anshan, China, Part II: Case-control studies of lung and stomach cancer.

Nested case-control interview studies of lung cancer (610 incident cases), stomach cancer (292 incident cases), and 959 controls were conducted to follow up leads from a proportional mortality analysis of deaths among male workers in a large integrated iron-steel complex in Anshan, China. For lung cancer, after adjusting for the significant non-occupational risk factors (smoking, other pulmonary disease, family history of lung cancer, and low consumption of fruit or tea), risks were significantly elevated for those employed for 15 or more years in smelting and rolling (OR = 1.5, CI = 1.1-2.2), in the fire-resistant brick factory (OR = 2.9, CI = 1.4-5.9), in general loading (OR = 2.5, CI = 1.0-6.1), and as coke oven workers (OR = 3.4; CI = 1.4-8.5). For stomach cancer, after adjusting for consumption of pickled vegetables, prior gastric diseases, family history of stomach cancer, low intake of fruits and vegetables, and education, risks were significantly elevated for those employed for 15 or more years in ore sintering and transportation (OR = 2.1, CI = 1.0-4.4), in the fire-resistant brick factory (OR = 2.5, CI = 1.1-5.8), in general loading (OR = 3.2, CI = 1.2-8.9), as boilerworkers and cooks (OR = 2.6, CI = 1.2-5.6), and as coke oven workers (OR = 5.4, CI = 1.8-16.0). For both lung and stomach cancers, significant dose-response gradients were observed for exposure to total dust and benzo(a)pyrene, but not for specific chemical components of dust. Overall, long-term steel workers with exposure to workplace pollutants had a 40% increased risk of both lung and stomach cancers. These case-control studies confirm many of the occupational findings reported in the proportionate mortality analysis, and suggest avenues for further work to evaluate the carcinogenicity of individual components of dust.

Adult↗
PubMed1996

Lifestyle, environmental pollution and lung cancer in cities of Liaoning in northeastern China.

Several studies were conducted in cities of Liaoning Province, one of the areas of China with heavy concentrations of industry, to investigate the effects of life-style factors and environmental pollutants on lung cancer causation. A case-control study involving 1249 lung cancer patients and 1345 population-based controls was conducted in 1985-1988 in Shenyang, the capital of Liaoning. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the disease in males and 37% in females. There was also a significant increase in lung cancer risk associated with an overall index of indoor air pollution due to coal-burning emission. The population attributable risk (PAR) for indoor air pollution was 13% for males and 17% for females. Risks were significantly increased for workers in the non-ferrous smelter (odds ratio (OR) = 2.6, 95% CI, 1.3-5.1), chemical and drug manufacturing (OR = 3.0, 95% CI, 1.0-8.0), and the glass and pottery industry (OR = 1.6, 95% CI, 1.0-2.5). Studies in the Anshan Iron-Steel Complex showed a significant excess of lung cancer for workers exposed to a variety of dusts. A standardized proportional mortality ratio (SPMR) study of 8887 deaths during 1980-1989 among male workers of the complex indicated a 37% excess risk of lung cancer compared to residents of the city. A nested case-control study was then conducted in that complex. A total of 610 cases of lung cancer diagnosed during 1987-1993 and 959 randomly selected controls from 196 993 active and retired employees of the complex were interviewed. Historical monitoring records for dust and benzo(a)pyrene (B(a)P) were collected from 1956-1992 to calculate cumulative exposure for each person. Results suggested that risks were increased for all occupations in which there was exposure to dusts, with the highest risks seen among coke oven workers (OR = 3.5, 95% CI, 2.0-6.4) and fire-resistant brick makers (OR = 2.9, 95% CI, 1.9-4.4). Significant dose-response patterns between cumulative total dust, cumulative total B(a)P and lung cancer risk were observed. The findings suggest that smoking and environmental pollution combine to account for elevated rates of lung cancer in cities of northeastern China.

Adenocarcinoma↗
PubMed1996

Properties and regulation of gap junctional hemichannels in the plasma membranes of cultured cells.

During the assembly of gap junctions, a hemichannel in the plasma membrane of one cell is thought to align and dock with another in an apposed membrane to form a cell-to-cell channel. We report here on the existence and properties of nonjunctional, plasma membrane connexin43 (Cx43) hemichannels. The opening of the hemichannels was demonstrated by the cellular uptake of 5(6)-carboxyfluorescein from the culture medium when extracellular calcium levels were reduced. Dye uptake exhibited properties similar to those of gap junction channels. For example, using different dyes, the levels of uptake were correlated with molecular size: 5(6)-carboxyfluorescein (approximately 32%), 7-hydroxycoumarin-3-carboxylic acid (approximately 24%), fura-2 (approximately 11%), and fluorescein-dextran (approximately 0.4%). Octanol and heptanol also reduced dye uptake by approximately 50%. Detailed analysis of one clone of Novikoff cells transfected with a Cx43 antisense expression vector revealed a reduction in dye uptake levels according to uptake assays and a corresponding decrease in intercellular dye transfer rates in microinjection experiments. In addition, a more limited decrease in membrane resistance upon reduction of extracellular calcium was detected in electrophysiological studies of antisense transfectants, in contrast to control cells. Studies of dye uptake in HeLa cells also demonstrated a large increase following transfection with Cx43. Together these observations indicate that Cx43 is responsible for the hemichannel function in these cultured cells. Similar dye uptake results were obtained with normal rat kidney (NRK) cells, which express Cx43. Dye uptake can be dramatically inhibited by 12-O-tetradeconylphorbol-13-acetate-activated protein kinase C in these cell systems and by a temperature-sensitive tyrosine protein kinase, pp60v-src in LA25-NRK cells. We conclude that Cx43 hemichannels are found in the plasma membrane, where they are regulated by multiple signaling pathways, and likely represent an important stage in gap junction assembly.

Alcohols↗
PubMed1996

Comparison of lucifer yellow leakage and cell-to-cell transfer following intracellular injection in normal and antisense Novikoff cells under treatment with low extracellular Ca2+.

Single and paired control Novikoff and connexin 43 antisense-transfected Novikoff cells (antisense cells) were used to investigate the differences of intercellular dye transfer and leakage between these two types of cells. Lucifer Yellow was injected into cells by iontophoresis. There was no dye leakage in single cells of both types in Swims solution. The dye transfer from injected cell to recipient cell in the normal solution was different in the two types of cell pairs. The transfer was significantly suppressed in antisense cells; 46/84 cases were blocked vs. 1/84 in Novikoff cell pairs. Under EGTA treatment, the dye leakage in single antisense cells was suppressed showing an increase in the very slow rate of leakage (16/40 vs. 6/40), and the mean rate of leakage was also significantly low. This suggests that dye transfer and leakage are suppressed in antisense cells and demonstrates that connexin 43 plays an important part both in dye transfer in paired cells and dye leakage in single cells.

Calcium↗
PubMed1995

[Progress in the study of potassium channels in cardiomyocytes].

The application of molecular biology and the development of patch clamp techniques led to a dramatic progress in the study of diversified and complicated K+ channels in the cardiomyocytes. Molecular studies suggested that all K+ channels are composed of four subunits encoded by genes from a big K+ channel gene family. The mechanisms of K+ channel inactivation include N-, C- and P-types of inactivation. S5-S6 linker was postulated to form the pore of K+ channels by site-directed mutagenesis. Though the molecular structures among K+ channels are very close, a wide range of their functional properties has been observed. The channel conductances, the characterizations of activation, inactivation, rectification and external K+ sensitivity, the agonists, antagonists and modulators of eight K+ channels found in cardiomyocytes up to now are different with each other.

Animals↗