L-Arginine Supplementation Improves Vascular Endothelial Dysfunction Induced by High-Fat Diet in Rats Exposed to Hypoxia.

INTRODUCTION: Our previous study showed that high-fat diet inhibited the increase in nitric oxide and endothelial nitric oxide synthase expression in the aortic endothelium of rats exposed to hypoxia, and hypoxia plus a high-fat diet led to earlier and more severe vascular endothelial dysfunction (VED) than hypoxia alone. The purpose of the present study was to investigate the effects of L-arginine on high-fat diet-induced VED of rats in hypoxia. METHODS: Forty male Sprague-Dawley rats were randomly divided into 4 groups and treated with hypoxia (H group), hypoxia plus high-fat diet (H+HFD group), hypoxia plus L-arginine (H+L-Arg group), and hypoxia plus high-fat diet and L-arginine (H+HFD+L-Arg group) for 1 wk. Hypoxia was simulated in a hypobaric chamber with an altitude of 5000 m. Aortic morphology and endothelium-dependent vasorelaxation were used to assess VED. RESULTS: High-fat diet impaired vascular remodeling and reduced endothelium-dependent vasodilator response to acetylcholine in rats exposed to hypoxia, secondary to dysregulation of the nitric oxide pathway. L-arginine supplementation significantly increased plasma nitrates and nitrites and endothelial nitric oxide synthase mRNA levels and improved ultrastructural changes in aortic endothelium and endothelium-dependent vasodilator response. CONCLUSIONS: L-arginine prevents aortic ultrastructural changes and reverses VED induced by high-fat diet in rats exposed to hypoxia, which may have implications for VED induced by high-fat diet in high altitude dwellers.

Direct filtration for the treatment of the coagulated domestic sewage using flat-sheet ceramic membranes.

Direct membrane filtration (DMF) is considered as a promising technology for municipal wastewater treatment. We utilized an innovative application of flat-sheet ceramic membranes (FSCM) for DMF for the rapid treatment of domestic sewage. Coagulation was applied before FSCM filtration to increase the pollutant removal and to mitigate membrane fouling. This coagulation-FSCM filtration can significantly reduce the pollutant load on the downstream treatment and concentrate organics and nutrients into sludge to facilitate resource recovery. Using polyaluminum chloride (PACl) based FSCM filtration, approximately 90.0% of the chemical oxygen demand (COD) and 99.0% of the phosphorus (P) were removed from the sewage influent and retained in the concentrated sludge, with less than 25.0 mg/L COD left in the effluent. Long-term operation of the PACl-based FSCM filtration stably maintained a high flux of 41.7 L/m2-h (LMH, or 1.0 m/d). The fouled membranes were cleaned chemically every 3-5 d, and the membrane permeability could almost be completely recovered using chemical backwash for only 10 min with a diluted acidic, alkaline, chlorine or H2O2 solution. The novel FSCM process will fundamentally advance wastewater treatment technology. It can be readily modularized and installed as simple add-on units to upgrade and retrofit existing wastewater treatment systems.

Crocin Exhibits Antitumor Effects on Human Leukemia HL-60 Cells In Vitro and In Vivo.

Crocin is a carotenoid of the saffron extract that exhibits antitumor activity against many human tumors. However, the effects of crocin on HL-60 cells in vivo have not been evaluated. This study aimed to examine the effects of crocin on HL-60 cells in vitro and in vivo and investigate the underlying mechanisms. HL-60 cells were treated by crocin, and cell proliferation, apoptosis, and cell cycle profiles were examined by MTT assay, AO/EB staining, and flow cytometry, respectively. Furthermore, HL-60 cells were xenografted into nude mice and treated by crocin, the tumor weight and size were calculated, and the expression of Bcl-2 and Bax in xenografts was detected by immunohistochemical staining. The results showed that crocin (0.625-5 mg/mL) inhibited HL-60 cell proliferation and induced apoptosis and cell cycle arrest at G0/G1 phase, in a concentration and time-dependent manner. In addition, crocin (6.25, 25 mg/kg) inhibited the tumor weight and size of HL-60 xenografts in nude mice, inhibited Bcl-2 expression, and increased Bax expression in xenografts. In summary, crocin inhibits the proliferation and tumorigenicity of HL-60 cells, which may be mediated by the induction of apoptosis and cell cycle arrest and the regulation of Bcl-2 and Bax expression.

[Proliferative inhibition and apoptotic induction effects of crocin on human leukemia HL-60 cells and their mechanisms].

This study was to investigate the proliferative inhibition and apoptosis of human leukemia HL-60 cells induced by crocin and their possible mechanisms. The cell viability was tested by cell counting. The morphology of HL-60 cells was observed by fluorescence microscopy. The MTT assay was used to evaluate the inhibitory effect of crocin on the growth of HL-60 cells. Flow cytometry was used to measure the cell cycle. RT-PCR was used to detect bcl-2 and bax expression. The results indicated that the growth of HL-60 cells was inhibited remarkably in the dose and time dependent way. When the crocin concentration was higher than 5 mg/ml, the percentage of apoptotic HL-60 cells was not increased, on the contrary this percentage decreased, the cells manifested necrosis. Flow cytometry profiles revealed that cells were blocked in G0/G1 phase, the cell proliferation was inhibited obviously at 5 mg/ml. RT-PCR detection revealed that the expression of bcl-2 was down-regulated strikingly and bax was up-regulated. It is concluded that the crocin can inhibit the proliferation of HL-60 cells effectively, and block cells in G0/G1 phase. The mechanisms by which crocin induced apoptosis in HL-60 cells may be related to the inhibition of bcl-2 and activation of bax.

Phenolic acids analysis in ligusticum chuanxiong using HPLC.

A reversed-phase high-performance liquid chromatographic method with diode array UV detection is developed for the determination of five kinds of phenolic acids common in herbal medicines. Based on this method, ferulic acid and caffeic acid are found to be two main phenolic acids in Chuanxiong (one of the important crude drugs in traditional Chinese medicine). More important, ferulic acid is found to exist in free form, and caffeic acid--a previously unreported component--is found to exist in esterified or insoluble-bound form.