Design and application of a novel integrated electrochemical hydride generation cell for the determination of arsenic in seaweeds by atomic fluorescence spectrometry.

An integrated electrochemical hydride generation cell, mainly composed of three components (a gas liquid separator, a graphite tube cathode and a reticulate Pt wire anode), was laboratory constructed and employed for the detection of arsenic by coupling to atomic fluorescence spectrometry. This integrated cell was free of ion-exchange membrane and individual anolyte, with the virtues of low-cost, easy assembly and environmental-friendly. Using flow injection mode, the sample throughput could come to 120 h(-1) attributed to the small dimension of the cathode chamber. The operating conditions for the electrochemical hydride generation of arsenic were investigated in detail and the potential interferences from oxygen or various ions were also evaluated. Under the optimized conditions, no obvious oxygen quenching effects were observed. The limit of detection of As (III) for the sample blank solution was 0.2 ng mL(-1) (3sigma) and the relative standard deviation was 3.1% for nine consecutive measurements of 5 ng mL(-1) As (III) standard solution. The calibration curve was linear up to 100 ng mL(-1). The accuracy of the method was verified by the determination of arsenic in the reference materials GBW08517 (Laminaria Japonica Aresch) and GBW10023 (Porphyra crispata) and the developed method was successfully applied to determine trace amounts of arsenic in edible seaweeds.

Ectopic, autologous eutopic and normal endometrial stromal cells have altered expression and chemotactic activity of RANTES.

OBJECTIVE: To evaluate if the expression and chemotactic activity of RANTES are different in IL-1beta treated autologous eutopic endometrial stromal cells compared to ectopic and normal endometrium. STUDY DESIGN: Conditioned media from IL-1beta-treated ectopic, autologous eutopic and normal endometrial stromal cells were analyzed with a specific sandwich ELISA to quantify RANTES. The monocyte chemotactic activity of RANTES was assayed in a Boyden Chamber. RESULTS: RANTES expression in IL-1beta-treated autologous eutopic and normal endometrial stromal cells was significantly lower than ectopic endometrium. Autologous eutopic endometrial stromal cells showed a significant increase in RANTES expression compared to normal endometrium after IL-1beta stimulation for 60 h. The monocyte chemotactic activities of these conditioned media were highly correlated with the immunoreactive RANTES concentration. We observed significantly increased monocyte chemotactic activity in conditioned media of ectopic stromal cells compared to autologous eutopic and normal endometrium. The different chemotactic activity of RANTES between the autologous eutopic and normal endometrial stromal cells was also statistically significant. RANTES accounts for the majority (62%) of the monocyte chemotactic activity in ectopic endometrial stromal cells conditioned media and 55% of that activity in autologous eutopic endometrium. CONCLUSIONS: Although the eutopic endometric of women with and without endometriosis are histologically similar, our findings confirm that different expression and chemotactic activity of RANTES exist between autologous eutopic and normal endometrium. The altered expression of RANTES and monocyte chemotactic activity observed in ectopic, autologous eutopic and normal endometrium suggest the autologous eutopic endometrium may contribute to the pathogenesis of endometriosis.

[Influence of nuclear factor-kappaB decoy oligonucleotides on RANTES expression and monocyte chemotactic activity in stromal cells of ectopic endometrium].

OBJECTIVE: To study the inhibitory effect on the expression of regulated upon activation, normal T cell expressed and secreted (RANTES) and monocyte chemotactic activity of ectopic endometrial stromal cells by nuclear factor (NF)-kappaB decoy oligonucleotides (ODN). METHODS: The stromal cells of ectopic endometrium were divided into 3 groups. Two groups were cultured with or without 10 microg/L of interleukin (IL)-1beta. Another group was transfected with NF-kappaB decoy ODN with the aid of a lipofectamine reagent. After 4 h of transfection, 10 microg/L of IL-1beta was added to induce the stromal cells to secrete RANTES. Concentration of RANTES in the supernatant at 4, 8, 12, 24 and 36 h was measured with the sandwich enzyme linked immunosorbent assay (ELISA). U937 monocyte chemotactic activity was assayed in Boyden chambers. The specific RANTES-neutralizing monoclonal antibodies at serial doses (0.5, 1, 2, 4 and 8 mg/L) were added into IL-1beta induced medium of 24 h to detect the monocyte chemotactic activity of RANTES in supernatant. RESULTS: The concentration of RANTES secreted by stromal cells was respectively (58 +/- 10), (150 +/- 35), (360 +/- 46) and (586 +/- 42) ng/L after IL-1beta stimulation for 8, 12, 24 and 36 h, significantly higher than that of stromal cells cultured without IL-1beta. The concentrations of RANTES were respectively (86 +/- 16), (128 +/- 28) and (183 +/- 32) ng/L after IL-1beta stimulation for 12, 24 and 36 h in stromal cells transfected with NF-kappaB decoy ODN, evidently lower than that of stromal cells stimulated with IL-1beta alone. The monocyte chemotactic index of 12, 24, 36 h in conditioned medium of stromal cells transfected with NF-kappaB decoy ODN was respectively 10.3 +/- 0.9, 13.7 +/- 1.1, 18.6 +/- 1.2, which was evidently lower than that of stromal cells stimulated with IL-1beta alone. The anti-RANTES antibody at 0.5, 1, 2, 4 and 8 mg/L inhibited respectively 5%, 23%, 40%, 62% and 61% of the chemotactic activity in 12 h medium treated with IL-1beta. CONCLUSIONS: RANTES accounts for the majority of the monocyte chemotactic activity in IL-1beta induced medium of 24 h. NF-kappaB decoy ODN may influence the feed-forward inflammatory loop whereby IL-1beta from activated macrophages can lead to RANTES production by ectopic implants and further monocyte chemotaxis.

On-line sample digestion using an electromagnetic heating column for the determination of zinc and manganese in tea leaf by flame atomic absorption spectrometry.

A new on-line sample digestion system using electromagnetic induction heating technique was developed for the determination of zinc and manganese in tea leaf by flame atomic absorption spectrometry (FAAS). The homemade electromagnetic heating column (EMHC), whose effective diameter was about 1mm, was composed of a polytetrafluoroethylene (PTFE) outer tube and seven compactly packed PTFE coil-coated iron wires. The pre-digested sample solution was pumped through EMHC and then transferred directly to FAAS for determination. An analytical throughput of 72samplesh(-1) was obtained in the present system. Under optimal condition, the detection limits (3sigma) of zinc and manganese were 4.2mugL(-1) and 3.0mugL(-1), along with relative standard deviations (R.S.D.) of 3.2% and 3.6% respectively for zinc and manganese. Certified reference materials GBW 07602, GBW 07605 and GBW 08505 were analyzed to validate the proposed method, good agreement was achieved between the certified values and the obtained results.

Combined treatment of ionizing radiation with genistein on cervical cancer HeLa cells.

The anticancer agent genistein inhibits cell growth of tumor cell lines from various malignancies. In our study, we investigated the effectiveness of combined treatment of ionizing radiation (IR) with genistein on cervical HeLa cells and its possible mechanism. It was found that the inhibitory rate in cells with combined treatment was significantly higher than that of the cells treated with IR or genistein alone. After treatments of IR (4 Gy) combined with genistein (40 micromol/L), the apoptotic index of the cells was significantly increased and the cells were arrested in the G2/M phase. Survivin mRNA expression increased after IR (4 Gy), while it significantly decreased after combined treatment. These findings indicated that genistein enhanced the radiosensitivity of cervical cancer HeLa cells, and the mechanisms for this action might include increase of apoptosis, decrease of survivin expression, and prolongation of cell cycle arrest.