Hydrogen peroxide induces apoptosis in human hepatoma cells and alters cell redox status.

Direct exposure of human hepatoma cell line SMMC-7721 to hydrogen peroxide (H2O2) can induce apoptosis. Apoptosis induced by H2O2 was inhibited by cycloheximide, actinomycin D, 3-aminobenzamide, EGTA or Zn2+. H2O2 can increase the level of intracellular Ca2+, downregulate GSH levels, slightly induce lipid peroxidation, and lead to change in the ratio of reduced ion components to oxidized ion components of cells. Analysis of flow cytometry indicates that H2O2 decreases the level of Bcl-2. The data indicate that H2O2-induced apoptosis requires new mRNA and protein syntheses; H2O2 can activate Ca2+/Mg2+-dependent endonuclease leading to internucleosomal DNA fragmentation and activation of poly (ADP-ribose) polymerase interfering with the energy metabolism of the cell. The H2O2 downregulation of GSH may be more important for apoptosis than H2O2 induction of lipid peroxidation, and the H2O2 induced changes in redox status of the cell may be among the original events which lead up to other biochemical changes.

[Quantitative stereologic analysis of metabolize dynamic of protein and DNA during somatic embryogensis in Lycium barbarum L].

The protein and DNA content in somatic embryos of Lycium barbarum L were analysed using quantitative stereologicai procedure formed from Cell Morphometry. The photos were transformed into digital images by the Sharp JX-610 scanner. Then the quantity of protein and DNA was count applying digital images processing software. By the result we discuss the relationship between changes in protein and DNA metabolize dynamic and somatic embryogensis.

[Effects of modulation of abscisic acid during somatic embryogenesis in Lycium barbarum L].

Using Enzyme Linked Immunosorbent Assay (ELISA) method, we determined the ABA contents of different stages in somatic embryogenesis. The results showed that endogenous ABA contents increased to maximum value twice during somatic embryogenesis. After first maximum value of ABA contents embryogenic cells were observed in callus, and simultaneously, there was a specific protein of somatic embryogenesis investigated by SDS-PAGE. This protein accumulates preferentially in embryogenic callus but not in transferred callus. So it is suggested that ABA could promote the expression of specific genes and the synthesis of embryogenic protein during somatic embryogenesis in Lycium barbarum L. and ABA play an important role in globular stage as well. In addition, treatment of non-embryogenic activity callus with 4 mumol/L exogenous ABA could stimulate somatic embryogenesis. And the ABA function mechanism in relation to somatic embryogenesis was discussed.

[Analysis of penbutolol and its metabolites in human body fluid by gas chromatography--mass spectrometry].

A method for the detection and identification of penbutolol and its metabolites in human body fluid by using gas chromatography-mass spectrometry was established. The urine was extracted with diethyl ether-isopropanol and the plasma was extracted with Sep-Pak column. After TMS derivatization the sample was analyzed with GC-MSD. Six metabolites of penbutolol were found in urine sample. The recovery was 90.83% for urine and 85.88% for plasma. The detection limit of penbutolol was 5 pg.

[Separation and identification of stimulants and their metabolites].

Forty-one stimulant drugs banned by the International Olympic Committee were studied after they were administered to human volunteers. The parent drugs and their metabolites in free or conjugated forms in human urine collected within 24 hours after administration of the drugs were extracted, separated and identified. The separation was performed on a capillary gas chromatograph with nitrogen-phosphorous detector, while the identification was achieved on a capillary gas chromatograph with mass-selective detector. The extract was injected into the gas chromatograph both directly and after derivatization with trifluoroacetic anhydride (TFAA) or N-methyl-N-trimethylsilyl trifluoroacetamide (MSTFA) as well as TFAA and MSTFA combined. The conjugated metabolites were studied after acid hydrolysis of the extract and then selectively derivatized as above. The results are summarized in 4 tables in the text.

[The identification of ephedrine and its analogues in urine by gas chromatography].

A sensitive and reliable method of analysis for ephedrine and its analogues was established by using GC and GC-MS. The columns used for both GC and GC-MS were HP-5, and the carrier gas was helium. NPD was used as the detector for GC. The urine sample was extracted with ether and submitted to GC. If positive, it was then submitted to GC-MS to identify its structure. The detection limits for ephedrine and its analogues are lower than 200 ng/ml urine. The recoveries are above 80%.

[Study on metabolism of phenmetrazine-like drugs and their metabolites].

We have studied the metabolism of phenmetrazine, phendimetrazine and morazone, and their metabolites in urine. A sensitive, specific method using GC/NPD was applied to the determination of the rate of excretion of the drugs quantitatively, diphenylamina being used as the internal standard. The ether extract was derivatized with TFAA reagent, the metabolites and their TFA derivatives were identified by GC/NPD and GC/MSD methods. Norephedrine, cathine, ephedrine and pseudoephedrine in small amount were identified.