Palladium-catalyzed aerobic regio- and stereo-selective olefination reactions of phenols and acrylates via direct dehydrogenative C(sp2)-O cross-coupling.

An efficient olefination protocol for the oxidative dehydrogenation of phenols and acrylates has been achieved using a palladium catalyst and O2 as the sole oxidant. This reaction exhibits high regio- and stereo-selectivity (E-isomers) with moderate to excellent isolated yields and a wide substrate scope (32 examples) including ethyl vinyl ketone and endofolliculina.

Effects of endothelin-1 on hepatic stellate cell proliferation, collagen synthesis and secretion, intracellular free calcium concentration.

AIM: To explore the effects of endothelin-1(ET-1) on hepatic stellate cells (HSCs) DNA uptake, DNA synthesis, collagen synthesis and secretion, inward whole-cell calcium concentration ([Ca2+]i) as well as the blocking effect of verapamil on ET-1-stimulated release of inward calcium (Ca2+) of HSC in vitro. METHODS: Rat hepatic stellate cells (HSCs) were isolated and cultivated. 3H-TdR and 3H-proline incorporation used for testing DNA uptake and synthesis, collagen synthesis and secretion of HSCs cultured in vitro; Fluorescent calcium indicator Fura-2/AM was used to measure [Ca2+]i inward HSCs. RESULTS: ET-1 at the concentration of 5X10(-8) mol/L, caused significant increase both in HSC DNA synthesis (2,247+/-344 cpm, P<0.05) and DNA uptake (P<0.05) when compared with the control group. ET-1 could also increase collagen synthesis (P<0.05 vs control group) and collagen secretion (P<0.05 vs control group). Besides, inward HSC [Ca2+]i reached a peak concentration (422+/-98 mol/L, P<0.001) at 2 min and then went down slowly to 165+/-51 mol/L (P<0.01) at 25 min from resting state (39+/-4 mol/L) after treated with ET-1. Verapamil (5 mol/L) blocked ET-1-activated [Ca2+]i inward HSCs compared with control group (P<0.05). Fura-2/AM loaded HSC was suspended in no Ca2+ buffer containing 1 mol/L EGTA, 5 min later, 10(-8) mol/L of ET-1 was added, [Ca2+]i inward HSCs rose from resting state to peak 399+/-123 mol/L, then began to come down by the time of 20 min. It could also raise [Ca2+]i inward HSCs even without Ca2+ in extracellular fluid, and had a remarkable dose-effect relationship(P<0.05). Meanwhile, verapamil could restrain the action of ET-1(P<0.05). CONCLUSION: Actions of ET-1 on collagen metabolism of HSCs may depend on the transportation of inward whole-cell calcium.

Clinical evaluation of four one-week triple therapy regimens in eradicating Helicobacter pylori infection.

AIM: To evaluate clinical efficacy of four one-week triple therapies in eradicating Helicobacter pylori infection. METHODS: In this clinical trial, 132 patients with duodenal ulcer and chronic gastritis were randomly divided into four groups, and received treatment with OAC (omeprazole 20 mg + amoxicillin 1 000 mg + clarithromycin 250 mg), OFC (omeprazole 20 mg + furazolidone 100 mg + clarithromycin 250 mg), OFA (omeprazole 20 mg + furazolidone 100 mg + amoxicillin 1 000 mg) and OMC (omeprazole 20 mg + metronidazole 200 mg + clarithromycin 250 mg), respectively. Each drug was taken twice daily for one week. The (13)C urea breath test was carried out 4-8 weeks after treatment to determine the success of H pylori eradication. RESULTS: A total of 127 patients completed the treatment. The eradication rate for H pylori infection was 90.3%, 90.9%, 70.9% and 65.6%, respectively in OAC, OFC OMC and OFA groups. CONCLUSION: A high eradication rate can be achieved with one-week OAC or OFC triple therapy. Thus, one-week triple therapies with OAC and OFC are recommended for Chinese patients with duodenal ulcers and chronic gastritis.