Biomarkers ; blood ; Biopsy, Needle ; utilization ; Hepatitis C ; complications ; Humans ; Liver ; pathology ; Liver Cirrhosis ; diagnosis ; pathology

The phytoestrogen genistein has been shown to relax agonist-preconstricted arteries in vitro, the mechanism of this relaxation remains incompletely understood. The present study aimed to investigate the effect of phytoestrogen genistein on the tension of rabbit femoral arteries in vitro and to determine the mechanism of such relaxation. The results are as follows: (1) genistein (10~40 micromol/L) relaxed femoral arterial rings in a concentration-dependent manner under the condition of precontraction induced by phenylephrine (PE, 1 micromol/L); (2) removal of the endothelium significantly inhibited genistein-induced relaxation; (3) pretreatment with NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 100 micromol/L) also significantly inhibited this relaxation by genistein, implying that the concentration-dependent vasorelaxation caused by genistein is endothelium-dependent and involved nitric oxide; and (4) pretreatment with an L-type calcium channel agonist, Bay K 8644 (0.5 micromol/L), also significantly inhibited the genistein-induced relaxation in both endothelium-intact and endothelium-denuded rings. The results suggest that the genistein-induced vascular relaxation of these rabbit arteries is partially endothelium-dependent and involves calcium antagonistic mechanism.
Animals ; Calcium Channels, L-Type ; drug effects ; metabolism ; Endothelium, Vascular ; drug effects ; metabolism ; Femoral Artery ; drug effects ; physiology ; Genistein ; pharmacology ; In Vitro Techniques ; Male ; Nitric Oxide ; metabolism ; Rabbits ; Vasodilation ; drug effects

The effects of genistein (GST) on intracellular calcium concentration ([Ca(2+)](i)) were investigated in guinea pig ventricular myocytes. [Ca(2+)](i) was detected by confocal microscopy and represented by relative fluorescent intensity (FI-F(0)) /FI(0), %). The results showed that GST (10-40 micromol/L) reduced [Ca(2+)](i) in normal Tyrode's solution, Ca(2+)-free Tyrode's solution and normal Tyrode's solution containing 3 mmol/L EGTA in a concentration-dependent manner. The effects of GST on [Ca(2+)](i) in normal Tyrode's solution were partially inhibited by pretreatment with sodium orthovanadate, a potent inhibitor of protein tyrosine phosphatase, or L-type Ca(2+) channel agonist Bay K8644. GST also markedly inhibited the ryanodine-induced [Ca(2+)](i) responses in Ca(2+)-free Tyrode's solution. When Ca(2+) waves were produced by increasing extracellular Ca(2+) concentration from 1 to 10 mmol/L, GST (40 micromol/L) could block the propagating waves of elevated [Ca(2+)](i), and reduce the velocity and duration of propagating waves. These results suggest that GST may reduce the [Ca(2+)](i) in isolated guinea pig ventricular myocytes. The inhibition of voltage-dependent Ca(2+) channel, tyrosine kinase inhibition, and alleviation of Ca(2+) release from SR are possibly involved in the GST effect.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester ; pharmacology ; Animals ; Calcium ; metabolism ; Calcium Channel Blockers ; pharmacology ; Calcium Channels, L-Type ; Genistein ; pharmacology ; Guinea Pigs ; Heart Ventricles ; Male ; Microscopy, Confocal ; Myocytes, Cardiac ; cytology ; metabolism ; ultrastructure ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; Sarcoplasmic Reticulum ; metabolism ; Vanadates ; pharmacology

AIMTo study the effect of taurine (Tau) on rabbit cardiomyocyte apoptosis during ischemia/reperfusion (I/R) injury.

METHODSRabbit heart I/R injury was induced by occluding the left anterior descending coronary artery for 45 min and reperfusion for 180 min. taurine (200 mg/kg) was intravenously injected 5 min before heart ischemia. Cardiomyocyte apoptosis was measured by using terminal deoxynucleotidyl transferase--mediated dUTP nick end labeling method (TUNEL), flow cytometry (FCM) and DNA agarose gel electrophoresis.

RESULTSDNA ladder pattern of DNA in myocardium was revealed by agarose gel electrophoresis in I/R group while was not found in Tau + I/R group. Apoptotic cardiomyocytes were sparse within ischemic myocardium at risk in Tau + I/ R group as compared with that in I/R group (TUNEL stain). Apoptosis rate in ischemic myocardium from I/R and Tau + I/R groups detected by flow cytometry was 17.66% +/- 1.54% and 4.86% +/- 1.23%, respectively. Fas and Bax protein expressions in ischemic myocardium of I/R group were higher than that in nonischemic myocardium group (P < 0.01), Bcl-2/Bax ratio in I/R group was lower than that in nonischemic myocardium (P < 0.01); while in Tau + I/R group, Fas and Bax protein expressions were lower than that in I/R group (P < 0.01), the Bcl-2/Bax ratio was higher than that in I/R group (P < 0.01).

CONCLUSIONTaurine reduced apoptosis of myocytes in I/R rabbit heart; its mechanism may involve Fas, Bax and Bcl-2 proteins expression.

Animals ; Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Male ; Myocardial Ischemia ; metabolism ; pathology ; Myocytes, Cardiac ; cytology ; drug effects ; Rabbits ; Reperfusion Injury ; metabolism ; pathology ; Taurine ; pharmacology

OBJECTIVETo investigate the effects of human cytomegalovirus (HCMV) on the proliferation of duct epithelial cells of human salivary gland (HSG).

METHODSThe expression of proliferating cell nuclear antigen (PCNA) and p53 were studied in 11 cases of parotid cytomegalic inclusive disease (PCID) using immunohistochemical staining method. The effects of human cytomegalovirus (HCMV) on the proliferation of HSG were investigated by MTT method in vitro. The expression of PCNA in HSG infected by HCMV was examined using immunocytochemical staining and Western blotting.

RESULTSPCNA was expressed weakly in most of megalic inclusion cells which were positive for HCMV, while all the megalic inclusion cells were p53 negative in all 11 cases of PCID. HCMV inhibited proliferation of HSG in vitro in a time dependent and dose dependent manner. Down-regulation of PCNA was shown in infected cells.

CONCLUSIONHCMV inhibits proliferation of HSG and down-regulation of PCNA may be an expression of the inhibition.

Cell Division ; Cells, Cultured ; Cytomegalovirus ; genetics ; pathogenicity ; physiology ; Cytomegalovirus Infections ; genetics ; pathology ; Down-Regulation ; Epithelial Cells ; pathology ; Female ; Humans ; Male ; Parotid Gland ; pathology ; virology ; Proliferating Cell Nuclear Antigen ; analysis ; Salivary Ducts ; pathology ; virology ; Tumor Suppressor Protein p53 ; analysis

AIMTo observe the effects of adenosine on intracellular calcium concentration ([Ca2+]i) level in guinea pig ventricular myocytes and to define the possible mechanisms involved.

METHODSThe effects of adenosine on [Ca2+]i were investigated in guinea pig ventricular myocytes. [Ca2+]i was detected by laser confocal microscopy and represented by relative fluorescent intensity ((FI-FI0)/FI0, %, FIo: control, FI: administration of drugs).

RESULTS(1) Adenosine (10, 50, 100 micromol/L) reduced [Ca2+]i of ventricular myocytes in both normal Tyrode's solution and Ca(2+) -free Tyrode's solution in a concentration-dependent manner. (2) Tyrode's solution containing 30 mmol/L KCl (high K+ Tyrode's solution) induced [Ca2+]i elevation in ventricular myocytes, while adenosine (10, 50, 100 micromol/L) markedly inhibited the increase in [Ca2+]i induced by KCl. (3) Pretreatment with DPCPX (1 micromol/L) significantly reduced the effects of adenosine (100 micromol/L) in high K+ Tyrode's solution. The effects of adenosine (100 micromol/L) on [Ca2+]i in high K+ Tyrode's solution were also partially attenuated by pretreatment with L-NAME (1 mmol/L). (4) Adenosine (100 micromol/L) markedly inhibited the low concentration of ryanodine-induced [Ca2+]i increase in Ca(2+) -free Tyrode's solution. (5) When the propagating waves of elevated [Ca2+]i (Ca2+ waves) were produced by increasing extracellular Ca2+ concentration from 1 mmol/L to 10 mmol/L, adenosine (100 micromol/L) could block the propagating waves of elevated [Ca2+]i, reduce the frequency and duration of propagating waves, and reduce [Ca2+]i as well.

CONCLUSIONAdenosine may reduce the [Ca2+]i in isolated guinea pig ventricular myocytes via inhibiting Ca2+ influx and alleviating Ca2+ release from sarcoplasmic reticulum(SR). The reduction of Ca2+ influx might be due to the inhibition of voltage-dependent Ca2+ channel via adenosine A1 receptor, and NO might be involved in this process.

Adenosine ; pharmacology ; Animals ; Calcium ; metabolism ; Cells, Cultured ; Guinea Pigs ; Heart Ventricles ; cytology ; Myocytes, Cardiac ; drug effects ; metabolism

Adult ; Bile Ducts, Intrahepatic ; abnormalities ; Cholestasis, Intrahepatic ; diagnosis ; etiology ; therapy ; Female ; Humans

This paper was aimed to study the effect of genistein (GST) on L-type calcium current (I(Ca,L)) in isolated guinea pig ventricular myocytes using whole cell patch-clamp recording technique. The results are as follows. (1) GST (10, 50, 100 micromol/L) reduced the voltage-activated peak amplitude of I(Ca,L) in a concentration-dependent manner. Daidzein (100 micromol/L), a structural analogue of GST which has little or no inhibitory effect on tyrosine kinase, produced no effect over the same concentration range on I(Ca,L) (n=5, P>0.05). (2) GST up- shifted the current-voltage (I-V) curve, but the characteristics of I-V relationship were not significantly altered, and the maximal activation voltage of I(Ca,L) was not different from that of control. GST did not affect the activation kinetics of I(Ca,L). (3) GST markedly shifted the steady-state inactivation curve of I(Ca,L) to the left, and accelerated the voltage-dependent steady-state inactivation of I(Ca,L). V(0.5) value was -28.6 +/-0.6 mV in the control and -32.8 +/-1.1 mV in the presence of GST. The kappa values were 5.8 +/-0.5 mV and 6.5 +/-0.9 mV, respectively (n=6, P<0.05). (4) GST markedly shifted the curve of time-dependent recovery of I(Ca,L) from the steady-state inactivation to the right, and slowed down the recovery of I(Ca,L) from inactivation (n=7, P<0.01). (5) Sodium orthovanadate (1 mmol/L), a potent inhibitor of tyrosine phosphatase, significantly inhibited GST-induced inhibition (n=6, P<0.01). From the results obtained it is concluded that genistein inhibits I(Ca,L) and acts on the inactivated state of L-type calcium channel. This inhibitory effect of GST involves protein tyrosine kinase inhibition in guinea pig ventricular myocytes.
Animals ; Calcium Channel Blockers ; pharmacology ; Calcium Channels, L-Type ; drug effects ; Genistein ; pharmacology ; Guinea Pigs ; Heart Ventricles ; cytology ; Male ; Myocytes, Cardiac ; cytology ; drug effects ; Patch-Clamp Techniques ; Protein-Tyrosine Kinases ; antagonists & inhibitors

The effect of limb ischemic preconditioning (LIP) on ischemia-reperfused myocardium was examined in the urethane-anesthetized rats to determine whether LIP produces cardioprotection and to observe the roles of adenosine and neural reflex in this effect. The area at risk (AR) and infarct area (IA) were determined using Evans blue and nitro-blue tetrazolium staining respectively. Infarct size (IS) was defined as 100xIA/AR (%). The results obtained are as follows: (1) During 30 min myocardial ischemia and subsequent 120 min reperfusion, the myocardial infarct size occupied 51.48+/-0.82% of the area at risk. (2) LIP significantly reduced the myocardial infarct size to 35.14+/-0.88% (p<0.01 ), indicating the cardioprotective effect of such an intervention. (3) Femoral nerve section (FNS) completely abolished the cardioprotection afforded by LIP. (4) Intrafemoral artery injection of adenosine (10 nmol/kg) produced a similar effect to that of LIP, reducing the myocardial infarct size to 37.28+/-1.68%, while intrafemoral vein injection of the same dose of adenosine showed no effect. (5) Pretreatment with a selective adenosine A(1) receptor antagonist 8-cyclopentyl-1,diproylxanthine (DPCPX ) (32 nmol/kg) partially abolished the cardioprotection of LIP on myocardium. Taken together, it is concluded that LIP reduces infarct size following myocardial ischemia-reperfusion, and that the locally released adenosine and thereby the activated relevant neural pathway play an important role in the cardioprotection provided by LIP.
Adenosine ; metabolism ; Animals ; Extremities ; blood supply ; Ischemic Preconditioning ; Male ; Myocardial Infarction ; pathology ; prevention & control ; Myocardial Reperfusion Injury ; pathology ; prevention & control ; Rats ; Rats, Sprague-Dawley

The effects of local injection of genistein on femoral, renal, and mesenteric vascular beds were investigated respectively by constant flow perfusion method in 72 anaesthetized rats. The results are as follows: (1) genistein (0.4, 0.8, 1.2 mg/kg) decreased the perfusion pressure (PP) of femoral vascular bed in a dose-dependent manner. The effect of genistein (0.8 mg/kg) was partially inhibited by L-NAME, or by sodium orthovanadate (50 microg/kg), a potent inhibitor of protein tyrosine phosphatase; (2) genistein also decreased the PP of renal vascular bed in a dose-dependent manner and the effect of genistein was completely inhibited by pretreatment with sodium orthovanadate, but unaffected by L-NAME; and (3) genistein decreased the PP of mesenteric vascular bed in a dose-dependent manner, an effect which was partially inhibited by sodium orthovanadate, but unaffected by L-NAME. From the results obtained, it is concluded that genistein can decrease the vascular tone in the femoral, renal, and mesenteric vascular beds with the underlying mechanism that involves tyrosine kinase inhibition, while in femoral arterial beds, it also involves NO release.
Animals ; Genistein ; pharmacology ; Hindlimb ; blood supply ; Kidney ; blood supply ; Male ; Mesentery ; blood supply ; Perfusion ; Protein Kinase Inhibitors ; pharmacology ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley ; Vasodilation ; drug effects