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Objective: To analyze the clinicopathologic characteristics of gastroenteropancreatic neuroendocrine neoplasm(GEP-NET) and explore the prognostic factors for patients with GEP-NET., Methods: Retrospectively reviews were conducted for the charts of 68 patients diagnosed pathologically with GEP-NET and treated at Sichuan Cancer Hospital during January 2001 to June 2012. The information of prognostic factors was retrieved and analyzed. Kaplan-Meier method was used to estimate survival rates and plot patient survival curves of patients at different levels of predictive factors. The association between clinicopathologic characteristic and prognosis in GEP-NET patients was assessed with Log-rank test. Meanwhile Cox proportional hazard model was used to select independent risk factors of patient survival., Results: Stomach (20/68,29.41%) and cardia (16/68,23.53%) were mostly involved. Frequent tumor sites for males were stomach and cardia (34/52,65.38%) while the most common site was intestinal canal for female (12/16) . Ages of disease onset were different significantly among patient groups of different sites (P = 0.023). The average age of intestinal NET was the highest while gastric NET had the lowest. During a median follow-up duration of 49 (3-120)months, there were 37 deaths (54.41%), including 30 from postoperative relapses. Postoperative survival time ranged from 4-115 months. The mean survival periods were (46 ± 7) months respectively. The 1, 3, and 5-year survival rates were 65.1%, 41.5% and 28.7% respectively. Univariate analyses showed that the risk factors of survival time were patient age over 60 years, tumor size > 2 cm, T2-4 stage of tumor, vascular invasion, lymph node metastasis, distant metastasis, positive surgical margin and pathological grades of neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinoma (MANEC). Multivariate analysis indicated independent risk factors were tumor size > 2 cm and pathological grades of NEC and MANEC., Conclusions: GEP-NET may occur at multiple sites of digestive system and lack specific clinical manifestations. Tumor size, distant metastasis and pathological grades were independent prognostic factors for GEP-NET patients.

Objective: To detect the changes of heat shock protein(HSP) expression in human hepatocellular carcinoma HepG2 cells after treated by quercetin through a proteomics strategy termed SILAC (stable isotope labeling by amino acids in cell culture)-MS (mass spectrometry)., Methods: HepG2 cells cultured in d3-labeled DMEM medium were passaged for more than ten generations to reach an enough high labeling ratio. MTT assay was used to assess the inhibitory effect of quercetin on proliferation of HepG2 cells. In SILAC, total protein was extracted from control HepG2 cells and those treated by 50 µmol/L quercetin for 48 h, and then mixed to a 1:1 ratio. After in-gel digestion and idenfication by LC-MS/MS analysis, quantification informations of changed proteins were acquired by searching on Mascot 2.0 program (MatrixScience Ltd., London) against SWISS-PROT protein database. To ensure a high confidence level for identification, those peptides with Mascot scores below the threshold value were excluded from analysis and not included in the list of quantified proteins (P < 0.01). Protein abundance was calculated as ratios of the peak intensity of the fragment ions from the labeled versus the unlabeled peptides. RT-PCR was uesd to verify the reliability of HSPs changes by quercetin treatment from the SILAC-MS results., Results: After passaged for ten generations, the d3-labeling ratio was above 95%. MTT showed that quercetin inhibited the proliferation of HepG2 cells obviously, with a IC(50) close to 50 µmol/L, and in a dose-dependent and time-dependent manner. The MS showed that the expression of almost all heat shock family proteins was down-regulated a lot. The expression of HSP90 exposed to quercetin for 48 h was decreased to 49.3% of the normal HepG2 cells, and the expression of HSP70 was decreased to 43.6% of the normal Hep G2 cells. Quantitation information showed that the expression of HSP90α, HSP76, HSP60 and HSP27 was declined to 59.3%, 44.2%, 51.3% and 62.6%, respectively. Those results demonstrated that the quantification for changed protiens by SILAC-MS was correct., Conclusions: Quercetin can exert a significant inhibitory effect on whole expression of heat shock proteins in HepG2 cells. We suppose this maybe one of the pathways through which quercetin plays an important anti-tumor role. SILAC-MS is a reliale technique and can be used to quantify the changes of whole protein spectrum in HepG2 cells before and after treatment with some exogeneous factors.

Objective: To explore the feasibility of using enriched bone marrow (BM) compound with fibrin glue (FG) in repairing old radial bone defect., Methods: Totally 36 New Zealand rabbits were equally randomized into three groups: simple FG group, BM+FG group, and enriched BM+FG group. A 1.5-cm segmental bone defect was made at the left radial in each animal. After one month, the defect was implanted with the engineered bone. Before implantation, a compound of enriched BM with FG underwent electron microscopy, long-term culture, and bacteriological culture. Four, 8, and 12 weeks after operations, the osteogenetic effect was evaluated using X-ray observation, HE staining, or Van Gieson staining, and a semi-quantitative analysis was performed., Results: Electron microscopy showed enriched BM were compatible well with FG. No bacterial contamination or oncogenicity was observed after long-term culture. X-ray showed the repair effectiveness was significantly higher in BM+FG group and enriched BM+FG group than in simple FG group. Eight and 12 weeks after surgery, the Yang scores were significantly higher in enriched BM+FG group than in BM+FG group [(9.348±0.364évs.(7.984±0.229éìF=40.167ìP=0.001; (12.664±0.388)vs. (10.584±0.836é, F=20.3647ìP=0.004]. In addition, the Yang's scores at bone defects in BM+FG group and enriched BM+FG group were higher at the 12(th) week than in the 8(th) week. (F=36.004ìP=0.001; F=155.141ìP=0.000; respectively)The bone defects were repaired at varied degrees were histologically observed in BM+FG group and enriched BM+FG group during the observations., Conclusion: Implantation of BM+FG or enriched BM+FG are effective in repairing old radial bone defects, while simple FG shows not such effect.

Objective: To investigate the preparation method of polystyrene core-poly (acrylamide-acrylic acid) shell fluorescent microspheres., Methods: The polystyrene core-poly (acrylamide-acrylic acid) shell (P-(St-co-AAM)) fluorescent microspheres were prepared using fluorescent microspheres as the core and acrylamide/acrylic as polymerization monomer. Reaction conditions affecting the morphology of core-shell structure including feeding mode, initiator, cross linker, pH, concentration and swelling were studied., Result: Fluorescent microscopy showed that the relatively uniform particle sizes were distributed in a range of 7-8 μm. Fourier transform infra-red spectroscopy (FT-IR) proved the existence of poly (acrylamide-acrylic acid) shell and amide group on the surface. The optimal conditions for seeding polymerization: azobisisobutyronitrile was used as the initiator in the absence of cross linker, after a 40 h swelling treatment by using alcohol with the appropriate reaction temperature (70 degree), reaction time (3 h) and pH(6-7). The average dispersion and stability were 25.14 % and 90.21%, respectively. The fluorescein release percentage was kept stable at approximately 30% after 40 h., Conclusion: The fluorescent microspheres prepared by this method have core-shell structure and satisfactory fluorescence properties with good dispersion and stability.

Objective: To investigate the effects of interleukin-1beta (IL-1beta) on intercellular adhesion molecule-1 (ICAM-1) expression on A549 cell and underlying signal transduction pathways., Methods: A549 cells were pre-incubated with SC-514 [nuclear factor-KappaB (NF-KappaB) inhibitor (IKappaB) kinase-2 (IKK-2) inhibitor] and/or pre-treated with 1 microg/L IL-1beta. The phosphorylated IKappaBalpha (pIKappaBalpha) and degradation of IKappaBalpha were determined by Western blotting with specific antibody at 5, 10, 30 and 60 minutes. Laser scanning confocal microscope (LSCM) was used to examine the nuclear translocation of p65 at 30 minutes after stimulation. The DNA binding activity of p65 in nuclear extracts was detected at 1 hour following IL-1beta treatment. Chromatin immunoprecipitation (ChIP) assays combined with polymerase chain reaction (PCR) were used to evaluate interaction between p65 and ICAM-1 promoter site DNA at 1 hour after stimulation. The expression of ICAM-1 mRNA was assessed by reverse transcription (RT)-PCR at 4 hours, and the ICAM-1 expression on A549 cell surface was measured by enzyme linked immunosorbent assay (ELISA) at 24 hours after IL-1beta was added., Results: IL-1beta induced rapid pIKappaBalpha augmentation and its subsequent degradation. LSCM graphs showed that IL-1beta stimulated the translocation of p65 from the cytosol to the nucleus. IL-1beta significantly increased the DNA binding ability of p65 (P<0.01) in cell nuclear extracts. ChIP-PCR suggested that both acetylated histone 4 and p65 were recruited to ICAM-1 promoter. IL-1beta significantly augmented ICAM-1 mRNA level at 4 hours and expression of ICAM-1 on A549 cell surface at 24 hours (both P<0.01). The IKK-2 inhibitor, SC-514, inhibited IL-1beta induced IKappaBalpha protein activity, blocked p65 nuclear translocation, caused a significant reduction in IL-1beta induced DNA binding activity for p65 and ICAM-1 mRNA expression, and suppressed ICAM-1 expression on A549 cell surface (all P<0.01)., Conclusion: These results suggest that the activation of NF-KappaB mediates IL-1beta induced ICAM-1 expression in A549 cells.

Objective: To determine the associations between the polymorphisms of N372H in BRCA2 gene and 135G/C in RAD51 gene and breast cancers., Methods: The allele and genotype frequencies of N372H in BRCA2 gene and 135G/C in RAD51 gene were analyzed with denaturing high performance liquid chromatography (DHPLC) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 71 women with breast cancers and 85 normal, women., Results: The women with breast cancers had higher frequencies of genotype HH of the N372H locus in BRCA2 gene than the normal women. No statistical difference in the polymorphic distribution of 135G/C in RAD51 gene was observed between the two groups of women., Conclusion: The genotype HH of the N372H locus in BRCA2 is associated with breast cancers, which might be a genetic risk factor for breast cancers in Chinese populations.

Objective: What is the best suitable position for neonates who were weaned from mechanical ventilation has not been identified. This study aimed to evaluate the effect of the supine and prone positions on oxygenation in neonates within 6 hrs after weaning from mechanical ventilation., Methods: Sixty neonates who were weaned from mechanical ventilation were randomly given prone or supine position (n=30 each). They all received oxygen inspiration and SPO2 was maintained in a normal range by adjusting the oxygen flow rate (FiO2). Blood PaO2 and PaCO2 levels were measured 1 and 6 hrs after weaning and then the alveolodouble ended arrowarterial oxygen partial pressure difference (A-aDO2), respiratory index and oxygenation index were calculated., Results: Mean FiO2 used in the prone position group was significantly lower than that in the supine position group 1 and 6 hrs after weaning (P<0.01). The value of A-aDO2 in the prone position group 1 hr (171.06+/-86.55 vs 253.62+/-71.56; P<0.01) and 6 hrs after weaning (105.85+/-78.18 vs 208.48+/-86.80; P<0.01) were significantly lower than that in the supine position group. The respiratory index in the prone position group 1 and 6 hrs after weaning (2.16+/-1.24 and 1.35+/-1.11) was also reduced compared to 3.74+/-1.68 and 3.65+/-1.28 in the supine position group (P<0.01). In contrast, PaO2 in the prone position group 1 hr (88.70+/-32.65 vs 73.43+/-17.68; P<0.01) and 6 hrs (84.10+/-13.95 vs 70.20+/-20.27; P<0.01) after weaning was significantly higher than that in the supine position group. The oxygenation index in the prone position group 1 and 6 hrs after weaning (213.49+/-88.96 and 275.23+/-108.83) increased significantly compared to 141.54+/-43.25 and 160.62+/-63.03 in the supine position (P<0.01)., Conclusions: The prone position is better than the supine position for the improvement of oxygenation within 6 hrs after weaning from mechanical ventilation in neonates.

Human immunodeficiency virus (HIV) is a retrovirus, belongs to Lentiviridae family. As long as viral genetic material entering into host cytoplasm, double-strand DNAs synthesis occurs which is catalyzed by reverse transcriptase (RT) with viral plus-strand RNA as template. This reverse transcription is a key link of HIV-1 life cycle and an important target for anti-HIV drug development. The process of reverse transcription can be divided into several steps: formation of minus-strand strong-stop DNA; the first translocation; initiation of plus-strand DNA synthesis; and, the second translocation and the completion of both strands. These steps can be detected individually by using polymerase chain reaction (PCR) according to the amplified products on the region of R/U5, U3, U5/PBS and the sequence between LTR and Gag. In this review, we summarize the principle for detecting stages of HIV-1 reverse transcription by using PCR.

Background & Objective: Morphine sulfate controlled-released tablet and morphine hydrochloride sustained-released tablet are preferred medicines for treating moderate-severe cancer pain. There are some differences between the two medicines in their efficacy, metabolism and adverse events. This study was to compare the efficacy and toxicities between morphine sulfate controlled-released tablet and morphine hydrochloride sustained-released tablet in treating moderate-severe cancer pain., Methods: A total of 121 patients with moderate-severe cancer pain were randomized into two groups: 61 were treated with morphine sulfate controlled-released tablet and 60 were treated with morphine hydrochloride sustained-released tablet. Analgesic efficacy and toxicities of the two medicines were observed., Results: Of the 61 patients treated with morphine sulfate controlled-released tablet, 12 had moderate pain, 49 had severe pain; the total response rate was 91.80%. Of the 60 patients treated with morphine hydrochloride sustained-released tablet, 13 had moderate pain, 47 had severe pain; the total response rate was 91.67%. There was no significant difference in the efficacy between the two medicines. Digestive system adverse events, including nausea, vomiting and constipation, were more common in morphine hydrochloride sustained-released tablet group than in morphine sulfate controlled-released tablet group (66.66% vs. 34.43%, P<0.05)., Conclusions: Both morphine sulfate controlled-released tablet and morphine hydrochloride sustained-released tablet are safety in treating moderate-severe cancer pain and the toxicities are tolerable. We recommend to take morphine sulfate controlled-released tablet for older patients and the patients with digestive disorders.

Background & Objective: Various potassium channels are known to be involved in proliferation of many malignant cell lines. This study was to explore the role of voltage-gated potassium channels in proliferation of human cervical carcinoma cells through observing the effects of tetraethylammonium (TEA) on proliferation and outward potassium currents in human cervical carcinoma cell line SiHa., Methods: SiHa cells were treated with TEA. The effect of TEA on proliferation of SiHa cells was assessed by MTT assay. Cell apoptosis and cell cycle were detected by flow cytometry with Hoechst 33258 staining. The outward potassium currents were recorded by patch clamp technique., Results: TEA inhibited the proliferation of SiHa cells in dose-and time-dependent manners, and induced cell apoptosis. The cell cycle was arrested at G0/G1 phase after treatment with TEA. Exposure of SiHa cells to 10 mmol/L TEA reduced the peak outward potassium currents significantly from (260+/-12) pA to (58+/-6) pA (P<0.01)., Conclusions: Voltage-gated potassium channels play an important role in regulating proliferation of cervical carcinoma SiHa cells. Blocking voltage-gated potassium channels could inhibit proliferation of SiHa cells.

Objective: To evaluate the clinical value of (99)Tc(m)-sandostatin receptors imaging ((99)Tc(m)-sandostatin) in detection of lung tumors in comparison with fludeoxyglucose F18 dual head coincidence imaging ((18)F-FDG DHC)., Methods: Fifty-six consecutive patients (40 men, 16 women; mean age: 62 years, range 35 - 80 years) with pulmonary neoplasm were referred for evaluation. All underwent sandostatin scintigraphy using hybrid SPECT/CT. (18)F-FDG DHC imaging was also performed in 23 patients using the same camera. The tumor uptake of (99)Tc(m)-sandostatin and (18)F-FDG DHC were measured respectively and expressed as the ratio of T/Nr and T/Nm. Final clinical diagnosis was confirmed by histopathological study., Results: Out of 56 cases, 46 were confirmed to be malignant and 10 benign. The sensitivity, specificity and accuracy of (99)Tc(m)-sandostatin in diagnosis of lung cancer were 95.7%, 90.0%, 94.6%, respectively. The positive predictive value (PPR) was 97.8%, and the negative predictive value (NPR) was 81.8%. In the 23 patients underwent both methods, the sensitivity, specificity and accuracy of (18)F-FDG DHC were 100%, 60.0%, 82.6%, respectively; the PPR was 76.5%, and the NPR 100%. Out of 13 patients with malignant neoplasms, 6 patients had regional lymph node metastasis, and all of 10 abnormal lymph nodules showed high uptake of FDG, while (99)Tc(m)-sandostatin imaging only 2 regional metastasized lymph nodes in one patient. T/N(r) and T/N(m) were 3.15 +/- 1.30, and 10.61 +/- 4.35 respectively. There was no relationship between sandostatin uptake and glucose metabolism., Conclusion: (99)Tc(m)-sandostatin scintigraphy is a promising noninvasive imaging technique for detection of the primary tumor of lung cancer but of limited value in the detection of lymph node metastasis.

Aim: To observe the effects of ouabain on vascular smooth muscle (VSM) of the guinea pig and its interactions with Ca2+ and norepinephrine (NE)., Methods: Using isolated thoracic aortic ring of the guinea pig, the degrees of contractile activity of drugs were recorded., Results: Ouabain showed a direct contractile effect in a concentration-dependent manner on thoracic aortic ring of guinea pig. Ouabain shifted the NE dose-response curve to the left without changing in the maxium response. Ouabain shifted the CaCl2 dose-response curve to the left and upward, increased the maximum response to Ca2+; In Ca(2+)-free medium, the ouabain induced contraction was abolished, an increase in extracellular Ca2+ restored the response; nifedipine and verapamil abolished the ouabain induced contraction., Conclusion: The ouabain induced contraction is mainly dependent on the extracellular Ca2+ concentration, independent on the presence of endothelia of aorta, suggesting that Ca2+ antagonist may treat the hypertension induced by ouabain. Ouabain, NE and CaCl2 have synergetic contractile effects, suggesting that the synergetic contractile effects of ouabain and NE may contribute to the generation and development of hypertension.

Objective: To evaluate the effects of Rbl on action potentials and force of contraction in guinea pig ventricular papillary muscles., Method: The ventricular papillary muscles of guinea pig were isolated regularly and immersed with Tyrode, s solution. The effects of Rbl (purified saponins of panaxnotoginseng) on the action potentials (AP), the slow action potentials and the force of contraction (FC) of the muscles were studied. The AP and FC were measured synchronously., Result: Rbl shortened the duration of AP, including APD2O and APD90, and reduced the FC(n = 5, P < 0.01), but didn't affect the rest potential (RP), the amplitude of action potential (APA), overshot (OS) and maximal upstrok velocity (Vmax). Rbl also decreased the APA of slow action potential, but quinidine had no such effects., Conclusion: Rbl may be a channel blocker.

Aim: To study modulation of protein kinase A (PKA) and protein kinase C (PKC) on the delayed rectifier potassium current (Ik)in guinea pig ventricular myocytes., Methods: The delayed rectifier potassium current was recorded by using whole cell arrangement of the patch-clamp procedure., Results: cAMP 150 micromol/L increased intracellularly Ik and Ik,tail(pA/pF) from 13.7 +/- 2.1 and 6.1 +/- 0.1 to 18.5 +/- 3.3 and 6.4 +/- 2.1 (P < 0.01, n=6). Ik and Ik,tail(pA/pF) were augmented by 8-CPT-cAMP 150 micromol/L extracellularly from 11.4 +/- 1.8 and 5.3 +/- 0.6 to 17.9 +/- 4.0 and 6.2 +/- 1.3. The half-maximal voltage of activation of Ik was shifted from + 23.3 mV to 18.7 mV by cAMP. Phorbol 12-myristate 13-acetate(PMA, 10.0 micromol/L) applied intracellularly caused an enhance effect on Ik, with increasing Ik and Ik,tail(pA/pF) from 12.9 +/- 1.8 and 5.0 +/- 1.7 to 23.7 +/- 2.8 and 7.5 +/- 1.1. With shifting position potential of depolarization, effect of PMA on Ik was gradually augmented. PMA resulted in shifting the slop of activation curve from +15.3 mV to +25.6 mV, with only a small effect on the half-maximal voltage of activation of Ik., Conclusion: Ik was increased by both PKA and PKC, with different characteristics of regulation.

Aim: To investigate the effect of 4-aminopyridine (4-AP) on ion channels of myocytes., Methods: L-type calcium channel and sodium channel currents were recorded in guinea pig single ventricular myocyte using whole-cell patch-clamp techniques., Results: 4-AP, 0.1, 0.5 and 1.0 mmol.L-1 were shown to inhibit L-type calcium channel currents (ICa, L) and sodium channel currents (INa) concentration-dependently. The percentage of inhibition were (11.6 +/- 1.7)%, (37.5 +/- 8.3)% and (54.5 +/- 6.9)% (P < 0.01) respectively for ICa, L, and (22.1 +/- 14.3)% (P < 0.05), (39.4 +/- 8.8)% and (62.3 +/- 6.8)% (P < 0.01) respectively for INa. 4-AP 0.5 mmol.L-1 shifted the I-V curves of ICa, L and INa upwardly., Conclusion: 4-AP blocked L-type calcium channel and sodium channels in guinea-pig ventricular myocytes concentration-dependently.

Aim: The L-Type calcium currents were investigated in normal, hypertrophied and amiloride-treated rat ventricular myocytes so as to clarify the possible cause of the action potential lengthening that has been reported in thyroxine-induced hypertrophy. The interactions between agents such as thyroxine, Ang II and phenylephrine which induced hypertrophy with amiloride on the calcium current were analyzed., Methods: Myocardial hypertrophy was induced by i.p. L-thyroxine in rats. The cell length, cell width and cell area were measured by image analysis technique. For recording ICaL, the whole cell patch clamp technique was used. Potassium currents were suppressed by replacing K+ ions with Cs+ ions in intracellular media, and sodium current was blocked by 50 mumol.L-1 tetrodotoxin., Results: The Ca2+ current was found to be larger in hypertrophied cells (783pA) than in normal cells (433pA) and in amiloride-treated cells (429pA). However, no significant difference was observed in current density (6.54, 8.33, 5.74 pA/pF) in normal, hypertrophied and amiloride-treated cells. ICa displayed the same voltage dependence in three cell types. The potential giving 50% of activation (V1/2) moved towards more negative and the slope of activation curve was smaller in hypertrophied cells than in normal cells and amiloride cells. When expressed as percentages, the maximal increases in ICa were obtained with 1 mumol.L-1 Ang II and 100 mumol.L-1 phenylephrine in normal cells (+45.5% and +81.8%). Thyroxine 100 mumol.L-1 showed no effect on ICa. After giving amiloride, Ang II and phenylephrine did not increase the amplitude of ICa., Conclusion: At the dose of 0.5 mg.kg-1.d-1, amiloride (p.o.) was shown to prevent the amplitude of ICa from increasing and to be effective against increases of amplitude of ICa by Ang II and phenylephrine.

Standard microelectrode technique and the whole-cell clamp technique were used to investigate the effects of tetrandrine and rotundine on the action potential of rabbit sinus node dominant pacemaker cell and calcium currents of ventricular myocytes from guinea-pig. The results indicate that: tetrandrine 1-200 mumol.L-1 and rotundine 3-300 mumol.L-1 decreased the action potential amplitude(APA), the maximal upstroke velocity (Vmax), spontaneous depolarizing velocity of phase 4(SP4) and prolonged the sinus circle length(SCL) in a dose-dependent manner. Tetrandrine 0.1 mumol.L-1 in combination with rotundine 0.3 mumol.L-1 was shown to effectively reduce the ICa of ventricular myotytes from guinea-pig, the rate of inhibition is 19.6%. The results suggest that the two drugs have a good synergistic effect on inhibiting calcium current. These results might also put forward a valuable theoretic base for using the two drugs together in treating patients.

The effects of benzyltetrahydropalmatine (BTHP) on delayed rectified K+ currents (Ik) expressed in Xenopus oocytes and Ik of toad (Bufo bufo gargarizans) oocytes were studied. The Ik expressed in Xenopus oocytes was measured after microinjection of mRNA isolated from carp fish (C anratus L.) brains with double -microelectrode voltage clamp technique. The maximum and mean value of Ik expressed in Xenopus oocytes were 600 nA and 360 +/- 104 nA, respectively. BTHP reduced the current amplitude of Ik expressed in Xenopus oocytes in 10-1000 mumol.L-1 dose-dependently, EC50 was 29 mumol.L-1. Also, the reduction of Ik of toad oocytes was 9.1%, 29.1%, 54.7% and 68.6% by BTHP 10, 30, 100 and 1000 mumol.L-1, respectively, EC50 was 33 mumol.L-1. The results showed that BTHP possesses an inhibitory effect on Ik, the main ion mechanism of antiarrhythmic action of BTHP.

The present study indicates that iv tetrandrine may transiently decrease blood pressure, while other hemodynamic parameters such as LVP, +/- dp/dtmax, LVEDP, HR and CO may not be significantly altered. During coronary occlusion three of five dogs developed ventricular fibrillation (VF) and died in the control group, i.e. incidences of VF and mortality were 60%. While tetrandrine (Tet) appeared to reduce the severity of ischemic injury. It may alleviate arrhythmia and prevent VF and death in four of the five dogs. Tet also attenuated Ca2+ accumulation in myocardial cell, reduced melondialdehyde (MDA) production in ischemic myocardial and decreased CPK release in comparison with the control. It appears that Tet may have significant protective effects against ischemia induced cardiac damage in anesthetized dogs.

Standard microelectrode and two-microelectrodes voltage clamp techniques were used to study the effects of linesinine (Lien), an alkaloid extracted from the green seed embryo of Nelumbo nucifera Gaertn, on slow action potentials (AP) and slow inward current (Isi). Lien 10-100 mumol/L was shown to concentration-dependently decrease the action potential amplitude (APA), the maximal velocity of phase 0 depolarization (Vmax) and prolong the sinus cycle length (SCL) of slow AP in isolated sinoatrial node (SAN) pacemaker cells of rabbits. On both slow APs of rabbit SAN cells and guinea pig papillary muscles partly depolarized by high K+, Bay K 8644 0.03 mumol/L markedly increased the APA and Vmax, which were obviously antagonized by Lien 10 mumol/L. Moreover, Lien 1-100 mumol/L was found to inhibit the Isi of canine cardiac Purkinje fiber in concentration-dependent manner. Lien 3 and 100 mumol/L reduced the peak value of Isi by 14% and 88% respectively. The results suggest that Lien possesses calcium antagonistic effects.

In isolated rat portal vein, benzyltetrahydrophalmatine (BTHP) 0.3-100 mumol.L-1 dose-dependently increased the spontaneous mechanical activity. However, BTHP 300 mumol.L-1 showed an inhibitory effect on the spontaneous contraction. BTHP 200 mumol.L-1 reversed positive staircase phenomenon to negative ones in left atrium of guinea pig and inhibited the amplitude and Vmax and shortened the action potential duration (APD50) of the slow action potentials induced by high K+ (24 mmol.L-1) in guinea pig papillary muscles. BTHP reduced also the contractile force in papillary muscles of guinea pig. These results suggest that BTHP possesses calcium antagonistic effect in high concentration.

Standard microelectrode and two-microelectrode voltage clamp techniques were used to study the effects of benzyltetrahydropalmatine (BTHP) on action potentials of isolated myocardium and transmembrane K+ and Ca2+ currents in Purkinje fibers. The effect of BTHP 3-100 mumol/L consisted of prolongation of the action potential duration and reduction of delayed rectifier current (Ik) in concentration-dependent manner. At concentration above 200 mumol/L, the contractile force of the isolated myocardium was depressed and in voltage clamp experiments the slow inward current (Isi) was reduced. These results suggest that the inhibition of Ik induced by BTHP was in relation to its anti-arrhythmic action.

Standard microelectrode techniques were used to study the effects of benzyltetrahydropalmatine (BTHP) on ouabain-induced delayed after depolarization (DAD) and triggered activity in isolated guinea pig papillary muscles. The results indicate that ouabain-induced DAD and triggered activity were abolished by BTHP 100 mumols/L. In anesthetized rabbit ECG heart rates were reduced in a dose-dependent manner from its control value of 288 +/- 14 to 261 +/- 14 (5 mg/kg) and 226 +/- 36 bpm (BTHP 10 mg/kg). P-R interval was prolonged. In His-bundle electrogram, H-V interval and V duration were not affected, but A-H interval was prolonged from 41 +/- 3 to 45 +/- 5 ms.

The mechanism of antiarrhythmic action and the electrophysiologic effects of 7-bromoethoxybenzene-tetrahydroptamine (EBP) have been studied using conventional microelectrode technique. The effect of EBP on the membrane ISi and I(X) currents were investigated in the canine cardiac purkinje fibres using the double microelectrode voltage clamp methods. EBP was shown to increase the duration of action potential at 20 and 90% of repolarization of isolated guinea pig papillary muscles. However, the amplitude of action potential, the resting potential and the overshoot and maximum rate of 0 phase depolarization (Vmax) remained unchanged. The membrane potential was held at 40 mV and command potential at -15 mV, 0.3 Hz 500 ms. After 10 min of perfusion of EBP 30 mumol/L, the slow inward current (ISi) was reduced markedly. When the holding potential was held at -20 mV, and the command potential at +10 mV, EBP (10-100 mumol/L) exerted a depressed effect on the delayed (outward) rectifier current (I(X)) in a dose-dependent manner. It may be concluded that the antiarrhythmic effects of EBP is mainly related to decrease the automaticity and prolong the duration of action potential at 20-90% of repolarization of isolated guinea pig papillary muscles.

The changes of monophasic action potential (MAP) in ischemic and reperfused feline ventricle in situ were studied. When the feline coronary artery was ligated the MAPD50 was found to be markedly shortened, the T wave and S-T segment were elevated evidently. Within seconds of releasing the coronary occlusion ventricular fibrillation and death occurred in all animals. Intravenous injection of BTHP markedly prolonged the MAPD50 and MAPD90 and reduced the heart rate, while no influence on T wave and S-T segment were observed. After occlusion of the coronary artery, the T wave and S-T segment only increased slightly and the MAPD50 recovered to its control level. During reperfusion the occurrence of ventricular fibrillation was significantly reduced. In contrast, prazosin, verapamil and propranolol did not show significant effect on changes of MAP, but BTHP and Pra, Ver and Pro all showed protective effect on feline ischemic and reperfused myocardia by ligation and reperfusion of the coronary artery with decrease of the number of arrhythmia, ventricular fibrillation and death. The order of antiarrhythmic action of these agents was BTHP = Pra greater than Ver greater than Pro. The total incidence of ventricular fibrillation reduced from the control values of 100% in ischemia/reperfusion heart to 0% (BTHP and Pra), 20% (Ver) and 40% (Pro).