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Objective Lung cancer is one of the malignant tumors with greatest morbidity and mortality around the world. The keys to targeted therapy are discovery of lung cancer biomarkers to facilitate improvement of survival and quality of life for the patients with lung cancer. Translationally controlled tumor protein (TCTP) is one of the most overexpressed proteins in human lung cancer cells by comparison to the normal cells, suggesting that it might be a good biomarker for lung cancer. Materials and methods In the present study, the targeted efficacy of dihydroartemisinin (DHA) on TCTP expression in the A549 lung cancer cell model was explored. Results and conclusions DHA could inhibit A549 lung cancer cell proliferation, and simultaneously up-regulate the expression of TCTP mRNA, but down-regulate its protein expression in A549 cells. In addition, it promoted TCTP protein secretion. Therefore, TCTP might be used as a potential biomarker and therapeutic target for non-small cell lung cancers.

The phenomenon of hydrate freeze-plugging is very widespread in Jilin oilfield M gas field exploitation. Freeze-plugging tends to occur in winter, mainly including ground pipeline, wellhead and wellbore freeze-plugging, etc, which affects the normal production of gas well, also has restricted the gas reservoir development and will cause huge economic losses. In order to prevent the freeze-plugging occurred in gas well, methyl alcohol is used to inject into single well at the rate of 600 to 3080 L/day. The field condition shows that the result of injecting methanol is not obvious, besides, the toxicity of methanol and its high cost already cannot satisfy the oilfield actual demand. Therefore, we need to research and develop new hydrate inhibitors with low cost and high efficiency to solve the problem of freeze-plugging.

This paper presents a new method to identify coherent generator groups in power system based on projection pursuit. Projection pursuit algorithm is introduced to model wide-area measured time series and analyses high-dimensional data in low-dimensional subspace. It could seek and extract key projection vectors reflecting generator coherent features and identify the coherency of generators according to projection directions of generators. The presented technique could realize real-time identification of coherent generators, in which grouping is based on measured data avoiding the impact of model parameters. It proves that the composition of principal components has corresponding relationship with system oscillation mode. Finally, China Southern Power Grid is used as testing system to verify the feasibility and effectiveness of the method.

After the casing broken, under the action of internal and external pressure, the sidewall rock surrounding the fracture occurred damage and fragmentation and entered into the wellbore by the fracture, accumulation in the borehole. Due to the different sizes of rock mass damage fragmentation, formulation program for milling and sandwashing in workover was largely affected, the paper was started from velocity of elastic longitudinal wave, based on probability theory and the application of fractal geometry theory, a new calculation method of rock fractal dimension was established. The traditional theory of rock mass damage fragment distribution was enriched. The rock mass damage fragment distribution was more easily and more efficiently forecasted. And the reference frame of parameter design for casing-damaged well work over was provided, and guiding site-operation was quickly and effectively constructed.

Although astragaloside IV, a saponin isolated from Astragalus membranaceus, has been shown to protect the myocardium against ischemia/reperfusion injury, its effect on the status of sarcoplasmic reticulum (SR) Ca2+ transport in the injured myocardium remains largely unknown. In this study, we investigated whether in cultured cardiomyocytes subjected to hypoxia and reoxygenation (H/R) administration of astragaloside IV during H/R attenuates the myocardial cell injury and prevents changes in Ca2+ handling activities and gene expression of SR Ca2+ pump. Cultured cardiomyocytes from neonatal rats were exposed to 6 h of hypoxia followed by 3 h of reoxygenation. Myocyte injury was determined by the release of cardiac troponin I in supernatant. Astragaloside IV significantly inhibited cardiac troponin I release after H/R in a dose-dependent manner. The diastolic [Ca2+]i measured with Fura-2/AM was significantly increased after reoxygenation. Astragaloside IV prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by H/R. Furthermore, the observed depressions in SR Ca2+-ATPase activity as well as the mRNA and protein expression of SR Ca2+-ATPase in hypoxic-reoxygenated cardiomyocytes were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV in H/R-induced injury may be related to normalization of SR Ca2+ pump expression and, thus, may prevent the depression in SR Ca2+ handling.

Accumulating evidence suggests an important role of the calcineurin signaling pathway in mediating the development of cardiac hypertrophy. It has also been reported that angiotensin-converting enzyme inhibitors (ACEIs) regressed cardiac hypertrophy in some animal and human models. In this study, we investigated the possible role of calcineurin in the regression of cardiac hypertrophy induced by the ACEI perindopril in rats with renovascular hypertension. The effect of the calcineurin inhibitor cyclosporine A (CsA) was also studied. Starting from 2 months after a two-kidney one-clip (2K1C) procedure, the rats that had developed progressive left ventricular (LV) hypertrophy were daily administered perindopril (1 mg/kg per day) or CsA (20 mg/kg per day) until 3 months. At the end of either treatment, the LV gravimetric, morphometric and histological measurements revealed the regression of LV hypertrophy; and the enzymatic assay, Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) showed that both calcineurin activity and the calcineurin protein and mRNA expression levels were significantly decreased compared with untreated 2K1C rats, but that LV systolic performance was unchanged by either treatment. These data suggest that the cardiac hypertrophy regression induced by the ACEI perindopril is likely mediated, at least in part, through inhibition of the calcineurin signaling pathway.

Dysregulation of intracellular Ca2+ homeostasis plays an important role in mediating myocardial injury. We tested the hypothesis that treatment with trimetazidine (TMZ) would improve intracellular Ca2+ handling in myocardial injury of rats. The control group received saline only (10 ml kg(-1) day(-1), i.p.) for 7 days. In a second group, isoprenaline (ISO; 5 mg kg(-1) day(-1), s.c.) was administered to rats for 2 days to induce an acute injury of the myocardium. In a third group, treatment with TMZ (10 mg kg(-1) day(-1), i.p.) was initiated 1 day before ISO administration and continued for 7 days (n = 7 rats in each group). Histopathological evaluation showed that TMZ prevented ISO-induced myocardial damage. TMZ preserved the ATP levels and decreased the maleic dialdehyde (MDA) content in the hearts compared with ISO-treated rats. The diastolic [Ca2+]i measured by loading with fura-2 AM in isolated cardiomyocytes was increased significantly in ISO-treated rats compared to the control animals. TMZ prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by ISO administration. The reduction in sarcoplasmic reticulum (SR) Ca2+ content in the heart cells and in cardiac SR Ca2+-ATPase activity in ISO-treated rats was abolished by TMZ, although there were no differences in SR Ca2+-ATPase protein levels between the control, ISO and ISO + 7 mz-treated rats. In addition, TMZ prevented the reduction in sarcolemmal L-type Ca2+ current density in the heart cells induced by ISO treatment. These results demonstrate that the treatment of rats with TMZ inhibited the increase of diastolic [Ca2+]i and prevented the decrease of SR Ca2+ content, SR Ca2+-ATPase activity and L-type Ca2+ current density in cardiomyocytes in ISO-mediated myocardial injury of rats. These changes in Ca2+ handling could help to explain the favourable action of TMZ in myocardial injury.

We have extracted and roughly purified astragalosides (AS) from Astragalus membranaceus, a natural herb used as a traditional Chinese medicine, regarded to have pharmacodynamic benefits of protecting injured myocardium. We hypothesized that the astragalosides might exert beneficial effect in myocardial lesion by preserving both energy metabolism and Ca2+homeostasis. Sprague-Dauley (SD) rats were injected with isoproterenol (ISO) subcutaneous (s.c.) at a dose of 5 mg/kg/day consecutively for two days as models and were treated with astragalosides and trimetazidine intraperitoneally (i.p.) respectively, at a dose of 5 mg/kg/day one day prior to isoproterenol for 8 days. The histological changes were alleviated in isoproterenol-injected SD rats treated with astragalosides. Compared with isoproterenol-injected rats, the concentration of myocardial intracellular [ Ca2+] i was decreased, L-type Ca2+current density and sarcoplasmic reticulum (SR) Ca2+load were recovered, the concentration of myocardial ATP was increased and phosphocreatine (PCr) was decreased in rats treated with astragalosides. In conclusion, the efficacious treatment of astragalosides for myocardial injury might be through regulating intracellular Ca2+homeostasis and energy metabolism.

In the aorta of the spontaneously hypertensive rat (SHR), endothelium-dependent contractions are enhanced by inhibitors of NO synthase and scavengers of NO, but not by methylene blue, an inhibitor of guanylyl cyclase, suggesting that the endothelium-derived contracting factor (EDCF) interacts chemically with NO and is inactivated by the latter. However, in view of the relative lack of specificity of methylene blue this hypothesis was re-examined. Acetylcholine-induced endothelium-dependent contractions of isolated rings of SHR aorta were significantly and similarly potentiated by two NOS inhibitors, by two structurally different NO scavengers, by two inhibitors of guanylate cyclase ODQ and NS2028, but to a lesser extent by methylene blue. The contraction of the isolated rat trachea in response to methacholine and the contraction of the rat aorta in response to both 8-isoprostane and KCl were inhibited significantly by methylene blue. Methylene blue binds to the M3 muscarinic receptor subtype but not to the TP receptor. Therefore, methylene blue is an antagonist of the M3 muscarinic receptor subtype, involved in the release of EDCF, and a non-specific inhibitor of TP receptor-mediated contractions, the receptor involved in the action of EDCF. These inhibitory effects of methylene blue are likely to counteract the effect of the inhibition of soluble guanylate cyclase. These results rule out the hypothesis according to which NO would chemically inactivate EDCF.

Objective: To compare the therapeutic effects of Astragaloside and Perindopril on myocardial sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) activity and the SERCA type 2 mRNA level in Coxsack-ievirus B3 (CVB3)-infected cardiomyocytes.Methods: Cultured cardiomyocytes of rats were divided into normal, model, Astragaloside and Perindopril groups. The model, Astragaloside and Perindopril groups were infected with CVB3. Meanwhile, the Astragaloside and the Perindopril groups were treated with Astragaloside (10 μg/ml) and Perindopril (1.3 μg/ml) respectively. Cytopathic effect (CPE), cardiac troponin I (cTnI), the SERCA activity and mRNA level of the SERCA type 2 were observed after 96 hours.Results: The CPE and cTnI of model group were significantly higher than those of normal, Astragaloside and Perindopril groups (P 0.05).Conclusion: Astragaloside and Perindopril were able to reverse the down-regulations of cardiac SERCA activity and mRNA expression caused by virus infection to alleviate the cardiomyocyte injury.

Multiple transforming growth factor-beta (TGF-beta) responsive elements have been identified within the 5'-flanking region of the plasminogen activator inhibitor type-1 (PAI-1) gene. This study was designed to characterize the major TGF-beta responsive element (-804 to -546). DNA footprint assays showed that the region of protein contact (-726 to -703) did not include consensus sequences for any known transacting factors. The results of UV cross-linking and Southwestern blot experiments showed that a protein of M(r) 100,000 specifically binds to the TGF-beta responsive element and that this protein undergoes post-transcriptional activation within 5 min after stimulation of Hep G2 cells by TGF-beta resulting in a marked increase in affinity for the target DNA sequence. These results show that stimulation of Hep G2 cells with TGF-beta increases the affinity of a novel 100-kDa protein for the major TGF-beta responsive element within the PAI-1 gene.

The effects of amylin and insulin on the phosphorylation of glycogen synthase and phosphorylase were investigated using rat diaphragms incubated with 32Pi. Muscles were incubated with insulin (200 nM) or amylin (200 nM) for 30 min before extracts were prepared. The 32P contents of the enzymes were determined after immunoprecipitation and SDS-polyacrylamide gel electrophoresis. Amylin increased both the activity ratio (-AMP/+AMP) and the 32P content of phosphorylase by approximately 2-fold. Insulin alone was without significant effect on phosphorylase, but insulin blocked the effect of amylin on increasing the phosphorylation of phosphorylase. Insulin increased the glycogen synthase activity ratio (low glucose-6-P/high glucose-6-P) by approximately 80%. Amylin decreased this ratio from 0.14 to 0.08 and increased the phosphorylation of synthase by approximately 40%. To investigate changes in phosphorylation of different sites in the synthase, the enzyme was subjected to exhaustive proteolysis with trypsin, and 32P-labeled fragments were separated by reverse phase high performance liquid chromatography. Insulin decreased the 32P contents of sites 3(a+b+c) and 2(a+b), which appears to account for the increase in synthase activity. Amylin increased phosphorylation of sites 1a, 1b, and 3(a+b+c), but not sites 2(a+b). With insulin plus amylin, phosphorylation of none of the sites was significantly changed. The results indicate that the effects of amylin on glycogen synthase must involve more than activation of cAMP-dependent protein kinase, as this kinase phosphorylates site 2 and does not phosphorylate sites 3(a+b+c).

To assess the parameters of cardiac structure and function of male Balb/c mice by the echocardiography.A total of 27 male Balb/c mice (from five to seven week old) were examined with a 13-MHz transthoracic linear-array transducer, hearts were removed from mice anesthetized with Nembutal, and the left ventricular (LV) mass were weighed.Complete 2-dimensional echocardiography for cardiac structure and function were obtained. Hemodynamic parameters were recorded. A correlation existed between LV weight (x) and echocardiographic LV mass (y) with the 2D) guided M-mode method: y = 1.15x + 3.26, (r = 0.80).Echocardiography appears to be a promising approach for noninvasively assessing LV mass and function in mice.

The protein encoded by adenomatous polyposis coli (APC) gene participates in the signaling transduction pathway. Substantial studies have revealed that hypermethylation of APC gene promoter is closely related to the pathogenesis and development of cancer. This study was to develop a real-time quantitative methylation specific PCR (real-time QMSP) method, and detect the methylation of APC gene promoter in plasma of lung cancer patients.Genomic DNA with methylated APC gene promoter was extracted from the lung cancer cell line NCI-H460 using phenol-chloroform and quantified by spectrophotometric measurements. DNA was added into 200 microL plasma samples of healthy volunteers to make 10-fold serial dilutions. Circulating DNA from simulated plasma samples, 78 lung cancer patients, 31 patients with benign lung diseases and 23 health controls was extracted using magnetic beads and modified by bisulfite. The concentration of cell-free methylated APC gene promoter in the plasma samples was quantified by the external reference method with the standard curve constructed using simulated plasma.The linear range of the real-time QMSP assay was 1.5x10(2)-1.5x10(5) copies/ mL and its lowest detectability was 1.5x10(2) copies per milliliter plasma. Of 78 lung cancer patients, positive methylation of the APC gene promoter was detected in tumor tissues of 40 cases. Among the 40 lung cancer patients, positive methylation of the APC gene promoter was found in the plasma of 19 patients (47.5%). The concentrations of methylated APC promoter in the 19 lung cancer patients ranged from 1.67x10(2) to 6.78x10(3) copies/mL, with a median concentration of 1.67x10(3) copies/mL. No positive methylation of the APC gene promoter was detected in the plasma of 38 lung cancer patients without APC gene methylation in tissues, 31 benign lung diseases and 23 healthy controls.The newly developed real-time QMSP method allows the quantitative measurement of APC gene promoter methylation in plasma. Hypermethylation of the APC gene promoter in plasma is a potential diagnostic marker for lung cancer diagnosis.

Introduction. Recently, calcineurin has been shown to induce cardiac hypertrophy. Mitogen-activated protein kinases (MAPK), including the extracellular-signal regulated kinases (ERK), the c-Jun NH2-terminal kinases (JNK) and the p38 MAPK (p38), have also been shown to be important in the transduction of trophic signals. The objective of this study was to investigate possible cross-talk between calcineurin and MAPK pathways in controlling renovascular hypertension-induced cardiac hypertrophy. Methods. Renovascular hypertension was induced by the two kidney-one clip method. The left ventricular weight (LVW) and the ratio of LVW to tibial length were measured to assay the degree of cardiac hypertrophy. Calcineurin activity and MAPK mRNA expression were measured. Results. In the left ventricle of rats with renovascular hypertension, calcineurin activity and JNK mRNA expression were increased while cardiac hypertrophy developed. Treatment with the calcineurin blocker ciclosporin A induced calcineurin inhibition and regression of cardiac hypertrophy with an improvement of cardiac diastolic function. The treatment also resulted in down-regulation of JNK mRNA expression, but the mRNA expressions of ERK and p38 were unchanged. Conclusions. There is cross-talk between the calcineurin and JNK pathway in controlling renovascular hypertension-induced cardiac hypertrophy. Inhibition of the calcineurin and JNK pathways may be the basis of reversal of cardiac hypertrophy by calcineurin blockers.

Hypermethylation of CpG islands in adenomatous polyposis coli (APC) gene has been detected in a variety of human tumors, which is involved in the pathogenesis of these tumors. In previous research, we detected APC promoter methylation in 47% lung tumor tissues. This study was to analyze the effect of APC promoter methylation on the gene transcription in 3 lung cancer cell lines.The methylation status of APC promoter 1A in lung adenocarcinoma cell line SPCA1, small cell lung cancer cell line NCI-H446, and big cell lung cancer cell line NCI-H460 was detected by methylation-specific polymerase chain reaction (MSP) and microarray methylated cord blood DNA served as positive control, and unmethylated cord blood DNA served as negative control. The expression of APC was examined by real-time quantitative polymerase chain reaction (PCR) with Sybr-Green I staining. After treatment of 1, 5, 10, 15 micromol/L DNA methyltransferase inhibitor 5-aza-2-deoxycytidine (5-aza-dC), the expression of APC in NCI-H460 cells was detected by real-time PCR.APC promoter 1A was methylated in NCI-H460 cells, and unmethylated in NCI-H446 and SPC-A1 cells. Hypermethylation was detected in all 5 CpG islands (687, 707, 714, 719, 726) of APC promoter 1A in NCI-H460 cells. The expression of APC in NCI-H460 cells was decreased by 26.04% of that in NCI-H446 cells and by 32.36% of that in SPCA1 cells. After treatment of 1, 5, 10, 15 micromol/L 5-aza-dC, the expression of APC promoter 1A in NCI-H460 cells was enhanced by 4.59, 5.78, 9.58, 5.98 folds, respectively.APC gene is hypermethylated in HCI-H460 cells, and its transcription coud be activated by 5-aza-dC.

Although astragaloside IV, a saponin isolated from Astragalus membranaceus, has been shown to protect the myocardium against ischemia/reperfusion injury, its effect on the status of sarcoplasmic reticulum (SR) Ca2+ transport in the injured myocardium remains largely unknown. In this study, we investigated whether in cultured cardiomyocytes subjected to hypoxia and reoxygenation (H/R) administration of astragaloside IV during H/R attenuates the myocardial cell injury and prevents changes in Ca2+ handling activities and gene expression of SR Ca2+ pump. Cultured cardiomyocytes from neonatal rats were exposed to 6 h of hypoxia followed by 3 h of reoxygenation. Myocyte injury was determined by the release of cardiac troponin I in supernatant. Astragaloside IV significantly inhibited cardiac troponin I release after H/R in a dose-dependent manner. The diastolic [Ca2+]i measured with Fura-2/AM was significantly increased after reoxygenation. Astragaloside IV prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by H/R. Furthermore, the observed depressions in SR Ca2+-ATPase activity as well as the mRNA and protein expression of SR Ca2+-ATPase in hypoxic-reoxygenated cardiomyocytes were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV in H/R-induced injury may be related to normalization of SR Ca2+ pump expression and, thus, may prevent the depression in SR Ca2+ handling.

The cardiovascular pre-participation screening proposal for young competitive athletes has the potential to save young lives. This study aimed to identify individuals at risk for potentially lethal cardiovascular diseases in athletes before competition. Between June 2005 and July 2005, 351 (170 male and 181 female) elite Chinese athletes from 21 sports were profiled. The 12-lead electrocardiogram and echocardiography were employed to evaluate cardiovascular diseases. The vast majority had no definitive evidence of cardiovascular disease. However, abnormal ECGs were identified in 16 athletes (4.5%), including 4 with distinctly abnormal and 12 with mildly abnormal patterns. Only 13 athletes (3.7%) had echocardiographic evidence of relatively mild valve regurgitation that had not been previously suspected. In three athletes with relatively mild ventricular septal hypertrophy (13-14 mm), it was not possible to discern with absolute certainty whether the wall thickening was a manifestation of hypertrophic cardiomyopathy or secondary to athletic conditioning ("athlete heart"). This screening protocol identified no athletes with definite evidence of hypertrophic cardiomyopathy, Marfan's syndrome or other cardiovascular diseases that convey a significant potential risk for sudden death or disease progression during athletic activity. This is largely due to the relative low prevalence of conditions resulting in sudden cardiac death in young athletes and high false positive/negative rates in the tests used as part of the screening process (due to a large overlap between cardiovascular changes due to pathology and those due to intense training).

Dysregulation of intracellular Ca2+ homeostasis plays an important role in mediating myocardial injury. We tested the hypothesis that treatment with trimetazidine (TMZ) would improve intracellular Ca2+ handling in myocardial injury of rats. The control group received saline only (10 ml kg(-1) day(-1), i.p.) for 7 days. In a second group, isoprenaline (ISO; 5 mg kg(-1) day(-1), s.c.) was administered to rats for 2 days to induce an acute injury of the myocardium. In a third group, treatment with TMZ (10 mg kg(-1) day(-1), i.p.) was initiated 1 day before ISO administration and continued for 7 days (n = 7 rats in each group). Histopathological evaluation showed that TMZ prevented ISO-induced myocardial damage. TMZ preserved the ATP levels and decreased the maleic dialdehyde (MDA) content in the hearts compared with ISO-treated rats. The diastolic [Ca2+]i measured by loading with fura-2 AM in isolated cardiomyocytes was increased significantly in ISO-treated rats compared to the control animals. TMZ prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by ISO administration. The reduction in sarcoplasmic reticulum (SR) Ca2+ content in the heart cells and in cardiac SR Ca2+-ATPase activity in ISO-treated rats was abolished by TMZ, although there were no differences in SR Ca2+-ATPase protein levels between the control, ISO and ISO + 7 mz-treated rats. In addition, TMZ prevented the reduction in sarcolemmal L-type Ca2+ current density in the heart cells induced by ISO treatment. These results demonstrate that the treatment of rats with TMZ inhibited the increase of diastolic [Ca2+]i and prevented the decrease of SR Ca2+ content, SR Ca2+-ATPase activity and L-type Ca2+ current density in cardiomyocytes in ISO-mediated myocardial injury of rats. These changes in Ca2+ handling could help to explain the favourable action of TMZ in myocardial injury.

Astragalosides were the main active components from a native Chinese herb Astragalus membranaceus. Recent studies have shown that Astragalosides have a protective effect on myocardial injury in rats. The present study was designed to investigate the effect of Astragalosides on intracellular calcium overload and sarcoplasmic reticulum calcium load (SR Ca 2+ load) in cultured cardiac myocytes from neonatal rats. Astragalosides (100 μg/ml) were incubated in the presence of isoproterenol (ISO) (10-5 M) for 72 hours in cardiomyocytes. Metoprorol (10-6 M), a β1-selective antagonist, was cultured in the same condition as Astragalosides. The result showed that intracellular calcium concentration ([ Ca 2+] i ) and SR Ca 2+ load increased in ISO-treated cardiac myocytes as compared to control (P2+] i and SR Ca 2+ load. Metoprolol also inhibited those increase. The mRNA expression and activity of sarcoplasmic reticulum Ca 2+ ATPase (SERCA) were enhanced following ISO treatment in cardiac myocytes, and these increases were inhibited by Astragalosides or metoprolol (P2+] i and SR Ca 2+ load, enhancing free radical removal and decreasing lipid peroxidation in ISO-treated cardiomyocytes, which might account for their protective effect on myocardial injury.

The present study was designed to determine whether or not an increase in endothelial intracellular concentration of calcium ([Ca2+]i) evokes endothelium-dependent contractions in the aorta from normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Acetylcholine, adenosine triphosphate (ATP) and the calcium ionophore, A 23187, produced endothelium-dependent relaxations in isolated aortic rings of both WKY and SHR. These relaxations in response to the three agonists were significantly smaller in the SHR when compared with the WKY. Endothelium-dependent contractions to acetylcholine, ATP and A 23187 were observed only in the aorta isolated from the SHR. In the presence of NG-nitro-L-arginine, an NO synthase inhibitor, the endothelium-dependent contractions in response to acetylcholine, ATP and A 23187 were potentiated significantly in the aorta SHR and were unmasked in that of WKY. However, the contractions were still significantly greater in SHR than in WKY. These contractions were abolished by indomethacin and valeryl salicylate (two cyclo-oxygenase inhibitors) as well as by S 18886 (a TP-receptor antagonist), indicating that the endothelium-dependent contraction produced by the three agonists share the same characteristics. The results of the present study indicate that the release/generation of endothelium-derived contracting factor, requires an increase in endothelial [Ca2+]i.

To investigate the changes of cardiac calcium handling proteins and endothelin system in dilated cardiomyopathy (DCM) rats and the effects of perindopril and bisoprolol on the remodeling ventricles.DCM rats were employed using a 2-kidney, 1-clip hypertensive and diabetic model. Some of the DCM rats were treated with perindopril and bisoprolol for 3 months, respectively. The ratio of left ventricular weight to body weight (LVW/BW), mRNA expressions of calcium handling proteins and endothelin receptors were determined. The alterations of maximum binding capacity (Bmax) and equilibrium dissociation constant (KD) values of cardiac endothelin receptors (ETR) and its subtypes were detected.Compared with those of normal control, blood pressure, and LVW/BW in the DCM rats were elevated. Sarcoplasmic reticulum calcium pump (SERCA) mRNA expression and SERCA activity decreased in the left ventricle. The ETR Bmax decreased, especially the endothelin receptor A. Endothelin converting enzyme activity and expression were elevated, and mRNA expressions of beta1-adrenoreceptor and inositol-3-phosphate receptor in some hearts increased as well. The administration of perindopril and bisoprolol could reverse myocardial hypertrophy and restore the imbalance of calcium handling proteins and endothelin system.The disorder of calcium handling proteins and endothelin system existed in the hearts of DCM rats. Treatment of perindopril and bisoprolol could reverse myocardial hypertrophy and changes in DCM rats.

The present study was to investigate the mRNA, protein expression and the activity of calcineurin in the hypertrophic heart, and to determine the effect of calcineurin inhibitor--cyclosporine A (CsA) on the regression of cardiac hypertrophy in renovascular hypertensive rats. Renovascular hypertension was induced by two kidney-one clip methods. Two months after the operation, cardiac hypertrophy was determined by histological analysis performed in some rats (2K1C-2M), then the rats were subdivided into 2 groups: (1) 3-month old two kidney-one clip group (2K1C-3M) with rats receiving 0.9% NaCl per day for one month, and (2) CsA-treated group with rats treated with CsA for one month. Sham-operated rats were used as control. The ratio of the left ventricular weight to tibial length (LVW/TL), the area of cardiac myocyte, mRNA and protein expression and the activity of calcineurin were determined. Both the LVW/TL and the cardiomyocyte area were significantly larger in 2K1C-2M and 2K1C-3M rats than in age-matched sham-operated rats. Treatment with CsA significantly attenuated the increase in the LVW/TL as well as the cardiomyocyte area. The mRNA, protein expression and the activity of calcineurin were significantly higher in 2K1C-2M and 2K1C-3M rats than those in the age-matched sham-operated rats, while the elevation of mRNA, protein expression and activity of calcineurin were significantly suppressed in the CsA-treated rats. In conclusion, calcineurin plays a role in the progression of cardiac hypertrophy in renovascular hypertensive rats. The inhibition of calcineurin can reverse cardiac hypertrophy.

This study was designed to determine the effect of pteridines, R- and S-tetrahydrobiopterin, sepiapterin, and dihydrobiopterin on endothelium-dependent contractions to acetylcholine in isolated aortas from spontaneously hypertensive rat and normotensive Wistar-Kyoto rat. The noncumulative addition of redox-active pteridines R- and S-tetrahydrobiopterin (but not the oxidized analogues sepiapterin and dihydrobiopterin) produced a concentration-dependent transient contraction in isolated aortic rings from both normotensive and hypertensive rats. R- and S-tetrahydrobiopterin (but not sepiapterin or dihydrobiopterin) potentiated the endothelium-dependent contractions to acetylcholine but only in aortas from hypertensive rats and in the presence of N G -nitro- l -arginine. In these aortas, the generation of oxygen-derived free radicals by the combination of xanthine plus xanthine oxidase also potentiated the endothelium-dependent contractions to acetylcholine. The presence of R-tetrahydrobiopterin did not alter the characteristics of the endothelium-dependent contractions because they were inhibited by valeryl salicylate, an inhibitor of cyclooxygenase-1, by S18886, a TP-receptor antagonist or by Tiron, a cell permeable superoxide anion scavenger. However, the contractions to acetylcholine, which are unaffected by the combination of superoxide dismutase and catalase, become significantly inhibited by these two scavengers in the presence of R-tetrahydrobiopterin. In the presence of N G -nitro- l -arginine, R-tetrahydrobiopterin did not affect the contractions to phenylephrine, U 46619, or to oxygen-derived free radicals generated by xanthine plus xanthine oxidase. These results indicate that the production of superoxide by the autoxidation of tetrahydrobiopterin selectively enhances endothelium-dependent contractions in the spontaneously hypertensive rat when nitric oxide synthase is inhibited.

A modified bioassay system was designed to demonstrate the diffusible nature of endothelium-derived contracting factor(s) released by acetylcholine in the aorta of spontaneously hypertensive rat. In “sandwich”-like layered preparation, isometric tension was recorded from a bioassay strip (without endothelium) in the presence of N G -nitro- l -arginine and tetrahydrobiopterin to selectively potentiate endothelium-dependent contractions. A donor strip (with or without endothelium) was stitched on the bioassay tissue so that it did not directly contribute to the recorded contractions. Acetylcholine induced contractions that occurred only when the donor strip was with endothelium. Superoxide dismutase did not affect but catalase and the combination of superoxide dismutase plus catalase significantly decreased the endothelium-dependent contraction. The contractions in the layered preparations were abolished when the donor strip with endothelium was treated previously with valeryl salicylate, an irreversible cyclooxygenase-1 inhibitor, but remained unaffected when the bioassay strip was treated with the compound. Previous treatment of the bioassay strip alone with S 18886 abolished the contractile response, whereas treatment of the donor strip with endothelium by the selective TP receptor antagonist only produced a moderate inhibition. These results indicate that in the aorta of spontaneously hypertensive rats, endothelium-dependent contractions to acetylcholine involve a diffusible substance(s) released by the endothelium. The production of this contracting factor(s) requires the activation of endothelial cyclooxygenase-1, and its action the activation of TP receptors on the vascular smooth muscle cells.

The B creatine kinase gene is regulated by an array of positive and negative cis-elements in the 5′-flanking DNA that function in both muscle and nonmuscle cells. In C2C myogenic cells M and B creatine kinase mRNAs are coordinately up-regulated in the early stages of myogenesis and then undergo distinct regulatory programs. The B creatine kinase gene is down-regulated in the late stages of myogenesis as M creatine kinase becomes the predominant species in mature myotubes. Sequences between −92 and +80 of the B creatine kinase gene confer a regulated pattern of expression to chimeric plasmids that closely resembles the time course of expression of the endogenous B creatine kinase gene in C2C cells undergoing differentiation. We show that sequences within the first exon of the B creatine kinase gene are important for the developmental regulation of the gene in C2C cells and that these sequences bind a nuclear protein that shows a similar tissue-specific distribution and developmentally regulated expression to that of the endogenous B creatine kinase gene.

Objective: To investigate the effects on myocardial injury and sarcoplasmic reticulum (SR) Ca2+ - ATPase of viral myocarditis mice treated with Astragaloside (AS) and Astragalus Injection (AI).Methods: Viral myocarditis model was created by intraperitoneal inoculation with coxsackievirus B3m (CVB3m ) solution and were divided into model, AS, AI and normal control groups. The mortality, myocardial pathological changes, serum cardiac troponin I (cTnl) and the activity of myocardial Sarco/Endoplasmic Ca2+-ATPase (SER-CA) were observed.Results: The mortality of model was higher than that of the normal control (P = 0. 0042), AS and AI (P

We have investigated the effects of insulin on the phosphorylation of glycogen phosphorylase in skeletal muscle. Rat epitrochlearis muscles were incubated in vitro with 32Pi to label cellular phosphoproteins, before being treated with hormones. Phosphorylase, phosphorylase kinase, and glycogen synthase were immunoprecipitated under conditions that prevented changes in their phosphorylation states. Based on measurements of the activity ratio (-AMP/+AMP) and the 32P content of phosphorylase, 4-8% of the phosphorylase in untreated muscles appeared to be phosphorylated. Epinephrine promoted increases of approximately 4-fold in the 32P content and activity ratio. Neither these effects nor the epinephrine-stimulated increases in phosphorylation of glycogen synthase and phosphorylase kinase were attenuated by insulin. However, insulin at physiological concentrations rapidly decreased the 32P content of phosphorylase in muscles incubated without epinephrine. Results from peptide mapping experiments indicate that phosphorylase was phosphorylated at a single site in both control and insulin on phosphorylase represented a decrease in 32P of approximately 50%. By comparison, the 32P content of glycogen synthase and the beta subunit of phosphorylase kinase were decreased by only 20 and 16%, respectively; the 32P content of the kinase alpha subunit was not affected by insulin. The results provide direct evidence that insulin decreases the amount of phosphate in phosphorylase and phosphorylase kinase. These findings have important implications with respect to both the regulation of glycogen metabolism in skeletal muscle and the mechanism of insulin action.

The effects of endotoxin administration on glycolytic and tricarboxylic acid cycle intermediates in dog livers were studied. Changes in metabolite concentrations were expressed graphically as percentages of controls using "crossover" plots in order to identify transitory rate-controlling steps. The results show that endotoxin administration increased glycolytic flux through pyruvate kinase, inhibited gluconeogenic flux through phosphoenolpyruvate carboxykinase, decreased glycogen storage, shifted cytosolic and mitochondrial redox state from a relatively oxidized to a more reduced state, decreased the extra- and intramitochondrial malate-aspartate and glutamate-alpha-ketoglutarate shuttle activities, depleted ATP, ADP, and NADP concentrations, and decreased energy charge. Based on these data, it is concluded that pyruvate kinase plays the major role in the control of glycolysis, while phosphoenolpyruvate carboxykinase is the major controlling step for the regulation of gluconeogenesis in dog livers during endotoxic shock. In addition, the major factor in the regulation of metabolic pathways that produce and utilize high-energy phosphates in the livers was impaired in endotoxic shock.