Metabonomic studies of pancreatic cancer response to radiotherapy in a mouse xenograft model using magnetic resonance spectroscopy and principal components analysis.

AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS (1)H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm(3), the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. (1)H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiation- treated pancreatic tumor tissues were compared. RESULTS: Compared with (1)H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the (1)H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.

Preparation and enantioseparation of a mixed selector chiral stationary phase derived from benzoylated tartaric acid and 1,2-diphenylethylenediamine.

L-Dibenzoyl tartaric acid was mono-esterified with benzyl alcohol, and then chlorinated with SOCl(2) to give (2S,3S)-1-(benzyloxy)-4-chloro-1,4-dioxobutane-2,3-diyl dibenzoate (Selector 1). (1R,2R)-1,2-Diphenylethylenediamine was mono-functionalized with phenyl isocyanate and phenylene diisocyanate in sequence to give (1R,2R)-1,2-diphenyl-2-(3-phenylureido)ethyl 4- isocyanatophenylurea (Selector 2). Two brush-type chiral stationary phases (CSPs) of single selector were prepared by separately immobilizing selectors 1 and 2 on aminated silica gel. Selectors 1 and 2 were simultaneously immobilized on aminated silica gel to give a mixed selector CSP. The enantioseparation ability of these CSPs was studied. The CSP of selector 1 has strongest separation ability, while the enantioseparation ability of the mixed selector CSP is relatively lower.

[PAHs in airborne particles from Tianjin in winter season].

Total suspended particles (TSP) samples from 13 stations in Tianjin were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) during 2002 winter. There was significant difference in total PAH concentration among 13 samples. TSP samples from the east Economic Development Area and mid-north districts had the highest contents of PAHs, while Dagang Oil Field had the lowest PAH content. The urban area, south district, and Jixian county had the moderate contents of PAHs. Based on the measured concentration of the PAHs, BaP equivalent (BaPeq) were derived based on Toxicity Equivalent Factors (TEFs) of the PAHs. The total BaPeq values were similar among the samples. The contribution of PAHs with five or six rings contributed 90% of the total toxicity, while they accounted for only 50% of the total concentration.