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Abstract Background Camptothecin (CPT) has recently attracted increasing attention as a promising anticancer agent for a variety of tumors. But the clinical application is largely hampered by its extreme water insolubility and unpredictable side effect. It is essential to establish an efficient and safe protocol for the administration of CPT versus melanoma. Methods Camptothecin was encapsulated with N-trimethyl chitosan (CPT-TMC) through microprecipitation and sonication. Its inhibition effect on B16-F10 cell proliferation and induction of apoptosis was evaluated by MTT assay and flow cytometric analysis in vitro. The anti-tumor activity of CPT-TMC was evaluated in C57BL/6 mice bearing B16-F10 melanoma. Tumor volume, tumor weight and survival time were recorded. Assessment of apoptotic cells within tumor tissue was performed by TUNEL assay. Antiangiogenesis and antiproliferation effects of CPT-TMC in vivo were conducted via CD31 and PCNA immunohistochemistry, respectively. Results CPT-TMC efficiently inhibited B16-F10 cells proliferation and increased apoptosis in vitro. Experiment group showed significant inhibition compared with free CPT-treated group (81.3% vs. 56.9%) in the growth of B16-F10 melanoma xenografts and prolonged the survival time of the treated mice (P < 0.05). Decreased cell proliferation, increased tumor apoptosis as well as a reduction in angiogenesis were observed. Conclusions Our data suggest that N-trimethyl chitosan-encapsulated camptothecin is superior to free CPT by overcoming its insolubility and finally raises the potential of its application in melanoma therapy.

The pure γ-Ca 2SiO 4 (γ-C 2S) phase was prepared at 1623 K of calcining temperature, 10 h of holding time and furnace cooling. The β-C 2S phase was obtained through γ-C 2S conversion with the following calcination system which was adopted at 1473 K of calcining temperature, 1 h of holding time and then water-cooling. The conversion rate of γ-C 2S was studied by the Rietveld quantitative laboratory X-ray powder diffraction supported by synchrotron X-ray diffraction images. The refinement results show that the final conversion rate of γ-C 2S is higher than 92%. The absolute error of the γ-C 2S conversion rate between two Rietveld refinements (sample with or without α-Al 2O 3) is 3.6%, which shows that the Rietveld quantitative X-ray diffraction analysis is an appropriate and accurate method to quantify the γ-C 2S conversion rate. [ABSTRACT FROM AUTHOR]

Chromophoric dissolved organic matter (CDOM) represents the fraction of the dissolved organic pool which absorbs light in the visible as well as UV ranges. It could affect the color of the waters. It is necessary to study it during in research on ecosystem, remote sensing of the water color and the cycle of carbon in waters. CDOM can fluoresce when excited, so fluorescence spectrum has been used to study its origin, distribution, and change. In the present article the fluorescence spectrophotometer was used to study the relation between the fluorescence intensity, spectrum area and the concentration of CDOM. When the concentration of CDOM is low (less than 75 mg x L(-1)), there is a better linear relationship (r2 > 0.98) between the fluorescence intensity, the spectrum area and the concentration of CDOM. Meanwhile good linear relations were found between the fluorescence intensity and spectrum area, which showed the same changeable trend of the fluorescence intensity and spectrum area with the concentration change of CDOM. A method was established to quantify the concentration of CDOM in water from different source using the linear relationship between the spectrum area and the concentration. It suits the complicated constituent analysis of CDOM and could really and accurately show the concentration of CDOM in natural water.

The determination of aconitine in biological samples by using TLC, HPLC and animal tests is described. TLC is simple, easy to manipulate and highly sensitive. The minimum detection limit was 0.3 microgram, so it can be used as a preliminary screening method. While detecting by HPLC, the characteristic UV-absorption spectrum of aconitine and animal tests were used as the qualitative methods. The characteristic UV absorption wavelengths were (228 +/- 2) nm and (275 +/- 2) nm. The linear range of calibration curve was 2 mg/L-50 mg/L. The coefficient of variation was 0.9996. It is suitable for applications in forensic field.