5-Nitro-2-(3-phenylpropylamino)benzoic Acid (NPPB) Stimulates Cellular ATP Release through Exocytosis of ATP-enriched Vesicles

Cells release ATP in response to physiologic stimuli. Extracellular ATP regulates a broad range of important cellular functions by activation of the purinergic receptors in the plasma membrane. The purpose of these studies was to assess the role of vesicular exocytosis in cellular ATP release. FM1-43 fluorescence was used to measure exocytosis and bioluminescence to measure ATP release in HTC rat hepatoma and Mz-Cha-1 human cholangiocarcinoma cells. Exposure to a Cl⁻ channel inhibitor 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) (50–300 μm) stimulated a 5–100-fold increase in extracellular ATP levels within minutes of the exposure. This rapid response was not a result of changes in cell viability or Cl⁻ channel activity. NPPB also potently stimulated ATP release in HEK293 cells and HEK293 cells expressing a rat P2X7 receptor indicating that P2X7 receptors are not involved in stimulation of ATP release by NPPB. In all cells studied, NPPB rapidly stimulated vesicular exocytosis that persisted many minutes after the exposure. The kinetics of NPPB-evoked exocytosis and ATP release were similar. Furthermore, the magnitudes of NPPB-evoked exocytosis and ATP release were correlated (correlation coefficient 0.77), indicating that NPPB may stimulate exocytosis of a pool of ATP-enriched vesicles. These findings provide further support for the concept that vesicular exocytosis plays an important role in cellular ATP release and suggest that NPPB can be used as a biochemical tool to specifically stimulate ATP release through exocytic mechanisms.     

Chromium and manganese levels in the scalp hair of normals and patients with breast cancer

The adverse health effects linked with chromium and manganese and the diverse cellular and molecular effects of chromium and manganese make the study of chromium and manganese carcinogenesis and toxicology very interesting and complex. Quantitative elemental analysis of scalp hair of breast cancer patients (stage III) (n=26) and controls (n=27) were used to study to find correlation and possible changes between breast cancer and healthy controls. The graphite furnace atomic absorption analysis of quantitative method was used for the determination of chromium and manganese element levels. Comparison of mean elemental contents of the breast cancer patients with controls shows a significant enhancement of chromium (p<0.05) but declining trends for manganase (p<0.05) in breast cancer patients. Changes in element content in hair can serve as a guide to opening up new vistas in the treatment of breast cancer on the basis of an overall analysis of symptoms and signs.     

Polyvinyl alcohol--trypsin as a catalyst for amino acid ester synthesis in organic media

The bovine trypsin-catalyzed synthesis of N-alpha-benzoyl-DL-arginine esters from N-benzoyl-DL-arginine were studied in various organic solvents. Trypsin was immobilized to polyvinyl alcohol (PVA) by adsorption from its aqueous solutions. Immobilized enzyme showed higher catalytic activities than free enzyme for amino acid esterification in ethanol. The yield of ester is strongly dependent upon the PVA/trypsin ratio and water content in the reaction medium. The rate and equilibrium constant of the ester formation reaction are also dependent on water content.     

The effects of aerobic exercise frequencies on liver fibrosis, α-fetoprotein and cytokeratin 19 in experimental type 2 diabetes-induced rats: an immunohistochemistry study

We investigated using immunohistochemistry the effects of frequency of aerobic exercise on liver fibrosis and measured the expression of the oval cell marker, alpha fetoprotein (AFP), and the hepatocellular carcinoma marker, CK 19, in rats with early-period induced type 2 diabetes (T2DM). Rats were divided into four groups: control sedentary rats, diabetic sedentary rats, diabetic rats with continuous exercise (30 min/day, 5 days/week) and diabetic rats with short periods of exercise (3 x 10 min/day, 5 days/week). T2DM was induced using an intraperitoneal (i.p.) injection of nicotinamide (NA) and streptozotocin (STZ). Liver samples were obtained 8 weeks after injection. Tissue sections were stained with hematoxylin and eosin, periodic acid-Schiff and Masson’s trichrome. We also used immunochemical staining for AFP, smooth muscle actin (α-SMA) and CK19. Continuous and short periods of aerobic exercise produced similar effects during the early period of liver damage in the STZ-NA model, i.e., decreased blood glucose levels and improved body weight, improved liver histology and reduced fibrosis, necrosis and steatosis; and reduced expression of AFP and α-SMA. Moderate aerobic exercise for 150 min/week appeared to reduce early liver damage in a rat model of T2DM.     

The Rates of Ca2+ Dissociation and Cross-bridge Detachment from Ventricular Myofibrils as Reported by a Fluorescent Cardiac Troponin C

The rate-limiting step of cardiac muscle relaxation has been proposed to reside in the myofilament. Both the rates of cross-bridge detachment and Ca(2+) dissociation from troponin C (TnC) have been hypothesized to rate-limit myofilament inactivation. In this study we used a fluorescent TnC to measure both the rate of Ca(2+) dissociation from TnC and the rate of cross-bridge detachment from several different species of ventricular myofibrils. The fluorescently labeled TnC was sensitive to both Ca(2+) dissociation and cross-bridge detachment at low Ca(2+) (presence of EGTA), allowing for a direct comparison between the two proposed rates of myofilament inactivation. Unlike Ca(2+) dissociation from TnC, cross-bridge detachment varied in myofibrils from different species and was rate-limited by ADP release. At subphysiological temperatures (<20 °C), the rate of Ca(2+) dissociation from TnC was faster than the rate of cross-bridge detachment in the presence of ADP. These results support the hypothesis that cross-bridge detachment rate-limits relaxation. However, Ca(2+) dissociation from TnC was not as temperature-sensitive as cross-bridge detachment. At a near physiological temperature (35 °C) and ADP, the rate of cross-bridge detachment may actually be faster than the rate of Ca(2+) dissociation. This provides evidence that there may not be a simple, single rate-limiting step of myofilament inactivation.     

Heterotrimeric G-proteins activate Cl- channels through stimulation of a cyclooxygenase-dependent pathway in a model liver cell line.

Circulating hormones produce rapid changes in the Cl(-) permeability of liver cells through activation of plasma membrane receptors coupled to heterotrimeric G-proteins. The resulting effects on intracellular pH, membrane potential, and Cl(-) content are important contributors to the overall metabolic response. Consequently, the purpose of these studies was to evaluate the mechanisms responsible for G-protein-mediated changes in membrane Cl(-) permeability using HTC hepatoma cells as a model. Using patch clamp techniques, intracellular dialysis with 0.3 mm guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) increased membrane conductance from 10 to 260 picosiemens/picofarads due to activation of Ca(2+)-dependent Cl(-) currents that were outwardly rectifying and exhibited slow activation at depolarizing potentials. These effects were mimicked by intracellular AlF(4)(-) (0.03 mm) and inhibited by pertussis toxin (PTX), consistent with current activation through Galpha(i). Studies using defined agonists and inhibitors indicate that Cl(-) channel activation by GTPgammaS occurs through an indomethacin-sensitive pathway involving sequential activation of phospholipase C, mobilization of Ca(2+) from inositol 1,4,5-trisphosphate-sensitive stores, and stimulation of phospholipase A(2) and cyclooxygenase (COX). Accordingly, the conductance responses to GTPgammaS or to intracellular Ca(2+) were inhibited by COX inhibitors. These results indicate that PTX-sensitive G-proteins regulate the Cl(-) permeability of HTC cells through Ca(2+)-dependent stimulation of COX activity. Thus, receptor-mediated activation of Galpha(i) may be essential for hormonal regulation of liver transport and metabolism through COX-dependent opening of a distinct population of plasma membrane Cl(-) channels.     

Effects of radial versus femoral artery access in patients with acute myocardial infarction: A large centre prospective registry

Aim

This study sought to assess whether radial artery access improves clinical outcomes in patients presenting with acute myocardial infarction compared with femoral artery access.

Methods

This is a single-centre, prospective observational registry of all STEMI and NSTEMI patients who underwent coronary angiography and/or primary PCI in the period January 2010 to December 2013. Primary endpoint was 30-day all-cause mortality. Choice of access was left to the discretion of the cardiologist. Differences in the risk of death at 30 days between patients undergoing transradial intervention versus transfemoral intervention was assessed on an intention-to-treat comparison.

Results

Retrospective analysis of prospectively collected data was performed in 3580 patients with an acute coronary syndrome who underwent coronary angiography, of which 1310 had radial artery access. PCI was performed in 77?% of the patients. Before propensity score matching, patients who underwent transradial intervention and those intended to undergo transfemoral approach differed significantly in intra-aortic balloon pump use (1.7?% vs. 6.7?%, p < 0.001), and Killip class (Killip 1: 10.8?% vs. 17.3?%, p < 0.001). 30-day mortality rates were 1.7?% in the transradial group and 4.6?% in the transfemoral group (p < 0.001). After matching on the propensity score, the hazard ratio for 30-day mortality in the transradial group was 0.56 (95?% CI: 0.29–1.07, p = 0.08).

Conclusion

This registry-based study showed that radial access is associated with improved outcome in patients with an acute coronary syndrome. However, this difference was no longer significant after multivariate and propensity score adjustment for differences in baseline characteristics.

     

Optimal pharmacological therapy in ST-elevation myocardial infarction—a review

Antithrombotic therapy is an essential component in the optimisation of clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. There are currently several intravenous anticoagulant drugs available for primary percutaneous coronary intervention. Dual antiplatelet therapy comprising aspirin and P2Y12 inhibitor represents the cornerstone treatment for STEMI. However, these effective treatment strategies may be associated with bleeding complications. Compared with clopidogrel, prasugrel and ticagrelor are more potent and predictable, which translates into better clinical outcomes. Therefore, these agents are the first-line treatment in primary percutaneous coronary intervention. However, patients can still experience adverse ischaemic events, which might be in part attributed to alternative pathways triggering thrombosis. In this review, we provide a critical and updated review of currently available antithrombotic therapies used in patients with STEMI undergoing primary PCI. Finding a balance that minimises both thrombotic and bleeding risk is difficult, but crucial. Further randomised trials for this optimal balance are needed.     

小花琉璃草化学成分的研究

从小花琉璃草(cynoglossum lanceolatym Forsk.)全草的石油醚提取物中分离到5个化合物,用波谱等方法鉴定为:十六碳酸甲酯(Hexadecanoic acid,methyl ester)、β-谷甾醇(β-sitosterol)、5α,豆甾烷-3,6-二酮(5α,stigmastane-3,6-dione)、6β-羟基-豆甾-4-烯-3酮(6-β-hydroxy-stigmasta-4-en-3-one)和胡萝卜甙(daucosterol)。     

The expression level of fibulin-2 in the circulating RNA (ctRNA) of epithelial tumor cells of peripheral blood and tumor tissue of patients with metastatic lung cancer

Molecular Biology Reports - The Fibulins are a recently discovered family of extracellular matrix proteins. In this study, expression levels of the fibulin-2 (FBLN2) gene and its role in the...