[Optimization of ultrasonic extraction conditions of safflower yellow from Carthamus tinctorius by response surface methodology].

OBJECTIVE: To investigate the optimization of extraction conditions of safflower yellow from Cartbamus tirwtorius by response surface methodology. METHODS: Experimental factors and levels were selected by one-factor test, and then according to the central composite experimental design principle, response surface'-methodology with three factors and three levels was used to establish a mathematical model to obtain the optimal extraction conditions with hydroxysafflower yellow A being the target and its extraction yield as response value. RESULTS: The optimal extraction conditions of safflower yellow were as follows: extraction temperature was 55 t, ratio of water to raw material was 16:1 and extraction time was 39 mm for three times. CONCLUSION: Under these conditions, the extraction yield of safflower yellow is 1.798%, and the relative error between the predicted value with actual value is 2.758%. The optimized method can provide reference for the efficient extraction of safflower yellow from Carthomos tinctorius

[Rapid simultaneous analysis of fluorene, carbazole, benzo[a]pyrene, and perylene by derivative-constant energy synchronous fluorescence spectroscopy].

A new method of derivative constant-energy synchronous fluorescence (CESF) spectroscopy for the simultaneous determination of fluorene, carbazole, benzo[a]pyrene and perylene was developed. The comparison and explanation of its performance are presented. The derivative CESF spectra are apparently more structured than the direct CESF. The scanning of derivative CESF is more effective than derivative constant-wavelength synchronous fluorescence spectroscopy. By using this method, real samples (tap water, seawater and airborne particulates) were determined directly and good results were obtained. The recoveries in tap water, seawater and airborne particulates were 90.0%-108.0%, 90.0%-104.0% and 90.0%-102.0% respectively.

Effects of cisplatin on telomerase activity and telomere length in BEL-7404 human hepatoma cells.

Telomerase activity was inhibited in a dose and time-dependent manner with the treatment of cisplatin for 24, 48, or 72 h in a concentration ranged from 0.8 to 50 microM in BEL-7404 human hepatoma cells. There were no changes in expression pattern of three telomerase subunits, its catalytic reverse transcriptase subunit (hTERT), its RNA component (hTR) or the associated protein subunit (TP1), after cisplatin treated for 72 h with indicated concentrations. Mean telomere lengths were decreased by the cisplatin treatment. Cell growth inhibition and cell cycle accumulation in G2/M phase were found to be correlated with telomerase inhibition in the present study, but percentages of cell apoptosis did not change markedly during the process.

In vitro Inhibition of Human Melanoma Cells by Immunotoxin Luffin B-Ng76.

Luffin B, a plan single-chain ribosome inactivating protein, was purified from seeds of Luffa cylindrica by Blue Sepharose CL-6B affinity chromatography. An immunotoxin was constructed with luffin B and Ng76, a monoclonal antibody to human melanoma cell M(21). Luffin B-Ng76 showed 4 000-fold more cytotoxic to target melanoma cells than free luffin B. The IC(50) of luffin B-Ng76 for M(21) cells and non-target HeLa cells was 2.5x10(-11) mol/L and 3.0x10(-8) mol/L, respectively. The results suggest that luffin B is a new potent immunotoxin effector.

Preparation and Use of a Monoclonal Antibodyagainst Luffin b.

Luffin b is one of the most toxic single chain plant ribosome inactivating proteins. It has been successfully used to prepare an immunotoxin against human melanoma cells. Two strains of hybridomas (1E5 and 2E1) were screened out using cell fusion technique which steadily secreted monoclonal antibodies against luffin b. These antibodies specifically reacted with luffin b. The affinity constants of 1E5 and 2E1 monoclonal antibodies were determined to be 1.1x10(9) mol(-1).L and 7.5x10(8) mol(-)1.L, by RIA,respectively. An immunoaffinity gel composed with the 1E5 monoclonal antibody and Sepharose 4B was prepared. The luffin b was successfully purified by one step immunoaffinity chromatography from the crude extract of Luffa cylindrica seeds. An immunoconjugate 1E5-HRP was also prepared and it was successfully used in Western blotting for detection of recombinant luffin b from E.coli total proteins.

Growth-inhibiting effects of taxol on human liver cancer in vitro and in nude mice.

AIM:To investigate the effects of taxol on SMMC-7721 human hepatoma and its mechanisms.METHODS:In vitro cell growth was assessed by trypan blue exclusion method. Experimental hepatoma model was established by seeding SMMC-7721 cells subcutaneously into Balb/c (nu/nu) nude mice. In vivo tumor growth was determined by measurement of tumor diameter with Vernier calipers. The syntheses of DNA, RNA and protein were analyzed by incorporation of (3)H-thymidine, (3)H-uridine and (3)H-leucine respec-tively. Using light and electron microscopes to observe the morphological changes of cells including mitosis and apoptosis.RESULTS:Taxol was effective against SMMC-7721 human hepatoma cell growth in the ranges of 2.5nmol/L-10nmol/L with mitotic arrest and apoptosis in vitro. DNA, RNA and protein syntheses in cells were also obviously suppressed by in vitro treatment of taxol for 72h. Taxol at 2.5nmol/L reduced (3)H-thymidine uptake to about 34% of the control value (P<0.05). Increasing the dose of taxol to 20nmol/L resulted in a greater decrease in (3)H-thymidine incorporation to 60% of the control value (P < 0.01). At a concentration of 20nmol/L, the (3)H-uridine and (3)H-leucine uptakes were reduced to 52% (P<0.05) and 63% (P<0.01), respectively. In vivo,taxol significantly inhibited SMMC-7721 tumor growth at 10mg/kg, i.p., once daily for 10d. A more than 90% decrease in tumor volume was observed by day 11 (P < 0.01) similarly with mitotic arrest and cell apoptosis.CONCLUSION:Taxol has a marked anticancer activity in SMMC-7721 human hepatoma both in vitro and in nude mice. Its mechanisms might be associated with mitotic arrest, subsequently, apoptosis of the hepatoma cells. No obvious toxicity was observed with in vivo administration of taxol.