Using whole-cell patch clamp technique this study investigated the effects of adenosine (Ado) on action potential, L-type calcium current (I(Ca.L)), delayed afterdepolarizations (DADs), and transient inward current (I(ti)) induced by isoproterenol (Iso) in guinea pig isolated single ventricular myocytes. The results showed: (1) Ado alone had no significant direct effects on action potential and I(Ca.L) in guinea pig ventricular myocytes at 20-100 micromol/L. However, Ado significantly attenuated the prolongation of action potential duration (APD) and the increase of the peak amplitude of I(Ca.L) induced by Iso. Iso (10 nmol/L) markedly increased APD(50) and APD(90) from 340+/-21 ms to 486+/-28 ms and from 361+/-17 ms to 501+/-29 ms, respectively (P<0.01), and increased the amplitude of I(Ca.L) from 6.53+/-1.4 pA/pF to 18.28+/-2.4 pA/pF (P<0.01). The peak potential of current-potential relationship shifted to the left. Ado (50 micromol/L) abbreviated APD(50), APD(90) to 403+/-19 ms and 419+/-26 ms (P<0.01), and decreased the peak amplitude of I(Ca.L) to 10.2+/-1.5 pA/pF (P<0.01 vs Iso), but did not change resting membrane potential (RMP), action potential amplitude (APA), and overshoot (OS). (2) Iso (30 nmol/L) reproducibly elicited DADs with 100% incidence of DADs under this condition. Ado (50 micromol/L) completely inhibited Iso from inducing DADs. Iso (30 nmol/L) elicited I(ti) with 2-second depolarizing voltage-clamp pulses rising to +20 mV from a holding potential of -40 mV, the incidence of I(ti) being 100%, and the I(ti) was suppressed in the presence of Ado (50 micromol/L) with the incidence of I(ti) decreased to 14.3% (P<0.05). These data indicate that Ado antagonizes the stimulatory effect of Iso, and that the antiarrhythmic mechanism of Ado preventing Iso-induced DADs is due to the inhibition of intracellular Ca(2+) overload through attenuating the prolongation of APD, the enhance of I(Ca.L) and I(ti).
Action Potentials ; drug effects ; Adenosine ; pharmacology ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; physiopathology ; Calcium Channels, L-Type ; drug effects ; Female ; Guinea Pigs ; Heart Ventricles ; cytology ; Isoproterenol ; antagonists & inhibitors ; Male ; Myocytes, Cardiac ; physiology ; Patch-Clamp Techniques

The purpose of this study was to investigate the different effects of ACh on the action potential and force contraction in guinea pig atrial and ventricular myocardium by using standard microelectrodes and force transducer. The results showed that the duration of the action potential (APD) of atrial myocardium was shortened from 208.57+/-36.05 to 101.78+/-14.41 ms (n=6, P<0.01), and the APD of the ventricular myocardium was shortened from 286.73+/-36.11 to 265.16+/-30.06 ms (n=6, P<0.01).The amplitude of the action potential (APA) of the atrial myocardium was decreased from 88.00+/-9.35 to 62.62+/-20.50 mV (n=6, P<0.01), while the APA of the ventricular myocardium did not change significantly.The force contraction of atrial myocardium was inhibited completely (n=6, P<0.01), while the force contraction of ventricular myocardium was inhibited by 37.57+/-2.58% (n=6, P<0.01). The ACh effects correlated with its concentration. The K(D) of the APD shortening effects in the atrial and ventricular myocardium were 0.275 and 0.575 micromol/L. The K(D) of the negative inotropic in the atrial and ventricular myocardium were 0.135 and 0.676 micromol/L, respectively. The corresponding data points were compared using t test between the atrial and ventricular myocardium, and the differences were significant when the ACh concentration was above 10 nmol/L. Furthermore, atropine (10 micromol/L) and CsCl (20 mmol/L) blocked the effects of 10 micromol/L ACh on the APD of ventricular myocardium, while CdCl2 (0.1 mmol/L) had no influence on these effects. In conclusion, ACh could shorten the action potential duration and inhibit the force contraction of atrial and ventricular myocardium in a concentration-dependent manner. There are differences in the effects of ACh on the atrial and ventricular myocardium. The atrial myocardium is more sensitive to ACh than the ventricular myocardium. It is probable that the muscarinic receptor and the potassium channel, but not the calcium channel, are involved in the ACh-induced shortening of the ventricular APD.
Acetylcholine ; pharmacology ; Action Potentials ; drug effects ; Animals ; Calcium Channels ; metabolism ; Guinea Pigs ; Heart Atria ; drug effects ; Heart Ventricles ; drug effects ; Microelectrodes ; Potassium Channels ; metabolism ; Receptors, Muscarinic ; metabolism

AIMTo observe the regulatory volume decrease (RVD) process of human intestine cells and investigate its ion channel mechanism.

METHODSCultured human intestine cells were exposed to hypotonic solution and the cell volume was measured using Coulter Counter System. RT-PCR was explored to detect the mRNA expression of Ca(2+) -activated K+ channel.

RESULTSHuman intestine cells showed a RVD process and this process could be blocked by Cl- channel blocker NPPB and K+ channel blocker TEA. Further results demonstrated the subtype of K+ channel involved in RVD was an intermediate-conductance, Ca(2+) -activated K+ channel (IK) because of its high sensitivity to clotrimazole. RT-PCR results also showed the expression of IK in this cell line.

CONCLUSIONThe RVD process of intestine cell was dependent on the parallel activation of Cl- channel and K+ channel. The subtype of K+ channel in volved in the RVD process was IK channel.

Cell Line ; Cell Size ; drug effects ; Chloride Channels ; antagonists & inhibitors ; metabolism ; Epithelial Cells ; cytology ; Humans ; Hypotonic Solutions ; Intestine, Small ; cytology ; Potassium Channel Blockers ; pharmacology ; Potassium Channels ; metabolism ; Potassium Channels, Calcium-Activated ; metabolism

The gating mechanism of ClC-1 chloride channel was studied in this paper by heteroexpression of rat wild type ClC-1 gene in Xenopus oocytes and by two-electrode voltage clamping technique. The deactivation gating kinetic parameters were obtained by applying two exponential fitting of the deactivating currents at various extracellular chloride concentrations. It was found that decrease in extracellular chloride concentration increased the fractional amplitude of fast deactivating component, and depressed the fractional amplitude of slow deactivating component accompanied by a decrease in fast and slow deactivating time constants. These results demonstrate that the deactivation kinetic parameters of ClC-1 are largely dependent on the extracellular chloride concentration, which induces changes in channel gating.
Animals ; Chloride Channels ; drug effects ; physiology ; Chlorides ; pharmacology ; Electrophysiology ; Female ; In Vitro Techniques ; Ion Channel Gating ; drug effects ; physiology ; Oocytes ; physiology ; Rats ; Xenopus

This study aims to analyze the molecular epidemiological characteristics of HIV-1 strains prevailing among men who have sex with men (MSM) in Beijing, China. The pol gene fragments from 250 newly diagnosed HIV-1-infected MSM individuals during 2006-2010 in Beijing were amplified by RT-nested PCR, sequenced, and phylogenetically analyzed. HIV-1 pol gene from 189 individuals were amplified and analyzed; 81 (42. 9%), 3 (1. 6%), 2 (1.0%), 88 (46. 6%), and 15 (7.9%) individuals were infected with HIV-1 subtypes B, B', C, CRF01_AE, and CRF07_BC, respectively. The subtypes B and CRF01_AE could both be grouped into two clusters, and CRFO7_BC strains shared high homology and were presumed to originate from a common ancestor. The HIV-1 circulating in MSM in Beijing had a lower genetic diversity than in heterosexuals. The HIV-1 epidemic (2006-2010) in MSM in Beijing was actually a rapid spread of HIV-1 CRF01 AE and B, or rather native strains of the two viruses.
Adult ; China ; epidemiology ; Epidemics ; Genetic Variation ; HIV Infections ; diagnosis ; epidemiology ; virology ; HIV-1 ; classification ; genetics ; isolation & purification ; Homosexuality, Male ; statistics & numerical data ; Humans ; Male ; Middle Aged ; Molecular Epidemiology ; Molecular Sequence Data ; Phylogeny ; Young Adult

OBJECTIVETo explore the effect of Herba Epimedii flavone (HEF) on the osteoblast metabolism in vitro.

METHODOsteoblast were obtained from new born rat calvaria by digestive enzymes. MTF, PNPP and RT-PCR were used to observe the proliferation, activity of ALP and mRNA expression of OPG and RANKL of cultured osteoblasts in vitro.

RESULTIt was found that HEF had the effect on stimulating cell proliferation, activity of ALP and the mRNA expression of OPG of cultured osteoblasts (P < 0.01, P < 0.05).

CONCLUSIONHEF can promote the proliferation, the differentiation and the expression of OPG mRNA of the osteoblasts cultured in vitro.

Alkaline Phosphatase ; metabolism ; Animals ; Animals, Newborn ; Carrier Proteins ; biosynthesis ; genetics ; Cell Proliferation ; drug effects ; Cells, Cultured ; Epimedium ; chemistry ; Flavones ; isolation & purification ; pharmacology ; Glycoproteins ; biosynthesis ; genetics ; Membrane Glycoproteins ; biosynthesis ; genetics ; Osteoblasts ; cytology ; metabolism ; Osteoprotegerin ; Plants, Medicinal ; chemistry ; RANK Ligand ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; genetics ; Receptors, Tumor Necrosis Factor ; biosynthesis ; genetics

OBJECTIVETo study the clinical characteristics of hepatitis B virus-related acute-on-chronic liver failure patients with familial aggregation.

METHODS275 patients with hepatitis B virus--related acute-on-chronic liver failure were investigated. The patients were divided into familial aggregation and non-familial aggregation group basis on their epidemiological features. Clinical data and biochemical indicators between the two groups were analyzed statistically.

RESULTS93 of 275 patients (33.82%) case were family aggregation. There was no significant difference compared with chronic hepatitis B patients (38.3%). The mean age of the two groups was 45.98 and 43.61 years old, respectively (P > 0.05). The rates of liver cirrhosis in family aggregation group were significant higher than non-familial aggregation group (73.91% vs 58.24%, p < 0.05). Serum total (TBil) and prothrombin activities (PTA) were no significant difference between the two groups, but ALT level in familial aggregation group was much higher (407.80 U/L vs 256.45 U/L, P 0.05).

CONCLUSIONFamilial aggregation were not related to acute-on-chronic liver failure in chronic HBV hepatitis patients. But the rate of liver cirrhosis were higher in patients with familial aggregation.

Acute Disease ; Adolescent ; Adult ; Aged ; Alanine Transaminase ; blood ; End Stage Liver Disease ; etiology ; genetics ; Family ; Female ; Hepatitis B ; complications ; Humans ; Liver Cirrhosis ; epidemiology ; Male ; Middle Aged

OBJECTIVETo observe the effect of puerarin on cell proliferation, differentiation, maturation and mineralization in cultured rat osteoblasts.

METHODOsteoblasts from craniums of newly born SD rats were cultured in vitro. MTT, PNPP and ARS were used to observe the proliferation, activity of ALP and the number of mineral node of cultured osteoblasts in vitro.

RESULTIt was found that puerarin had the effect on stimulating cell proliferation, activity of ALP and the number of mineral node of cultured osteoblasts (P < 0.01 or P < 0.05).

CONCLUSIONPuerarin can promote proliferation, differentiation, maturation and mineralization of the osteoblasts in vitro.

Alkaline Phosphatase ; metabolism ; Animals ; Calcification, Physiologic ; drug effects ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Isoflavones ; pharmacology ; Osteoblasts ; cytology ; enzymology ; Rats ; Rats, Sprague-Dawley ; Skull ; cytology

Objective To explore the feasibility of "immersion program" in French-taught surgical lessons,as to provide multiple educational methods and practical experiences for the application of bilingual education in clinical medicine.Methods Twenty-nine senior students of French-taught class were randomly divided into group A(n=15) and group B(n=14)."Immersion program" and "transitional bilingual education" were employed for group A and group B,respectively for the first half of teaching session,and "transitional bilingual education" and "immersion program" for the second half,respectively.The differences between the two bilingual education models were compared through quiz.Results In the prior 2 of the 4 quiz,the scores of French quiz and the total scores were much higher in "immersion program" group,and there were significant differences between the two groups(P0.05). Conclusion "Immersion program" helps to improve the ability of presentation,comprehension and application of French in the precondition of equal educational content,and it will be more beneficial when accessing the "immersion program" on the basis of "transitional bilingual education".

OBJECTIVETo investigate the etiology, pathology, and clinical characteristics of cryptogenic liver diseases in order to develop a pathogenic profile for clinical diagnosis and therapeutic design.

METHODSThe data of the 566 patients diagnosed with abnormal liver function and who had undergone liver biopsy at our institute between January 2006 to March 2010 were retrospectively analyzed. The Chi-squared (x²) test was used to assess disease correlation with sex and the rank sum test was used to assess disease correlation with continuous data since all data had asymmetric distribution.

RESULTSAmong the 566 patients, abnormal liver function was attributed to alcoholic liver disease (n=175; 30.92%), drug-induced or environmentally-induced liver disease (n=101; 17.84%), hereditary and metabolic disease (n=93; 16.43%), infectious hepatitis disease (n=84; 14.84%), fatty liver disease (n=53; 9.36%), and autoimmune liver disease (n=30; 53.00%). Thirty patients had unknown etiology, despite liver biopsy analysis. Among these disease subgroups, there were distinct correlations with sex, age, and levels of alanine transaminase (ALT) and gamma-glutamyltransferase (GGT). The autoimmune liver disease group was correlated with sex (q=9.14, 7.435, 5.071, 9.529, and 12.5, respectively; P less than or equal to 0.01). The alcoholic liver disease group and autoimmune liver disease group were correlated with age (vs. genetic metabolic disease group: q=17.254 and 10.302; infectious hepatitis group: q=17.523 and 10.697); drug/environmentally-induced liver damage group: q=9.170 and 5.266); fatty liver group: q=7.118 and 4.661) (P less than or equal to 0.01). In addition, the alcoholic and autoimmune liver disease groups were correlated with GGT levels (vs. genetic metabolic disease group: q=8.003; infectious hepatitis group: q=4.793; drug/environmentally-induced liver damage group: q=4.404) (P less than or equal to 0.01).

CONCLUSIONLiver pathology is important for the diagnosis of cryptogenic liver diseases. Patient age, sex, and biochemistry index may facilitate diagnosis and treatment in the absence of pathology.

Adolescent ; Adult ; Biopsy ; Child ; Child, Preschool ; Female ; Humans ; Liver ; pathology ; Liver Diseases ; classification ; diagnosis ; pathology ; Male ; Middle Aged ; Young Adult