[Modulation of drug-metabolizing enzymes and transporters under hypoxia environment].

Drug metabolism is significantly affected under hypoxia environment with changes of pharmacokinetics, expression and function of drug-metabolizing enzymes and transporters. Studies have shown that hypoxia increases the release of a series of inflammatory cytokines which can modulate drug metabolism. Besides, both hypoxia inducible factor 1α (HIF-1α) and microRNA-mediated pathways play a role in regulating drug metabolism. This article reviewed the impact and single-factor modulating mechanisms of drug metabolism under hypoxia, and put forward the speculation and prospects of multi-factor modulating mechanisms.

[Detection of plasma and urine furosemide based on online enrichment and restricted- access media coupled with high-performance liquid chromatography].

OBJECTIVE: To establish a method based on restricted access media-high performance liquid chromatography for direct online sample injection and detection of plasma and urine furosemide in rats. METHODS: The column of restricted access media was used as the pre-treatment column and a C18 column as the analytical column. The mobile phase of the pre- treatment column was water-methanol (95:5, V/V) with a volume percentage of formic acid of 0.1%. The mobile phase of the analytical column was methanol-water (65:35, V/V) for plasma and methanol-water (55:45, V/V) for urine samples, all containing a volume percentage of formic acid of 0.1% with a flow rate of 1 ml/min. The detection wavelength was 274 nm and the column temperature was maintained at 25 degrees celsius. RESULTS: The calibration curve showed an excellent linear relationship in rat plasma furosemide concentration range of 0.1-3.2 µg/ml (r=0.9995) and in urine concentration range of 0.5-32 µg/ml (r=0.9991). The average recoveries of furosemide at 3 spiked levels ranged from 101.82% to 113.36% for plasma and from 98.75% to 112.27% for urine samples. The detection showed good intra- and inter-day assay precisions and accuracies with the relative standard deviations all below 5%. The pharmacokinetic parameters AUC(0→24) was 6.265 g/(ml·h) with a t(1/2) of 2.447 h and a C(Max) of 1.414 g/ml. The mean cumulative excretory rate of furosemide in the urine of rats over 24 h was 32.50%-39.08%. CONCLUSION: Detection of furosemide in plasma and urine samples using restricted access media-high performance liquid chromatography is simple and efficient and allows direct online injection of the samples.

[Isolation and identification of nine iridoid glycosides from Lamiophlomis rotata by HPLC combining PDA and MS].

OBJECTIVE: To establish a rapid chromatographic method to separate the iridoid glycosides from Lamioplomis rotata, and to identify the target compounds with PDA and MS. METHODS: Methanol-water gradient elution was used to separate and analyze the target compounds. The fluid fractions were gathered according to the chromatogram and dried with the nitrogen airflow. The mass fractions of the target compounds were determined with RP-HPLC and the structures were identified with PDA and MS. RESULTS: The purity of some compounds exceeded 90% and these 9 compounds were identified as iridoid glycosides, which were Phlorigidoside C (1), Schismoside (2), Sesamoside (3), Shanzhiside methylester (4), 6-O-Acetyl shanzhiside methylester (5), Phloyoside II (6), Penstemoside (7), Loganin (8) and 8-O-Acetyl shanzhiside methylester (9). CONCLUSION: The method is simple and practicable with high efficiency. It can be used to qualitative and quantitative analysis of the 9 iridoid glycosides in Lamiphlomis rotata and its preparations.

Study on detection of mutation DNA fragment in gastric cancer by restriction endonuclease fingerprinting with capillary electrophoresis.

The DNA fragment detection focusing technique has further enhanced the sensitivity and information of DNA targets. The DNA fragment detection method was established by capillary electrophoresis with laser-induced fluorescence detection and restriction endonuclease chromatographic fingerprinting (CE-LIF-REF) in our experiment. The silica capillary column was coated with short linear polyarclarylamide (SLPA) using nongel sieving technology. The excision product of various restricted enzymes of DNA fragments was obtained by REF with the molecular biology software Primer Premier 5. The PBR322/BsuRI DNA marker was used to establish the optimization method. The markers were focused electrophoretically and detected by CE-LIF. The results demonstrate that the CE-LIF-REF with SLPA can improve separation, sensitivity and speed of analysis. This technique may be applied to analysis of the excision product of various restricted enzymes of prokaryotic plasmid (pIRES2), eukaryote plasmid (pcDNA3.1) and the PCR product of codon 248 region of gastric cancer tissue. The results suggest that this method could very sensitively separate the excision products of various restricted enzymes at a much better resolution than the traditional agarose electrophoresis.

[Effects on the pharmacokinetics of furosemide after acute exposure to high altitude at 4010 meters in rats].

The paper is to report the pharmacokinetics of furosemide in rats living at plain area and high altitude. After intragastric administration of furosemide (2.87 mg x kg(-1)), serial blood samples (0.5 mL) were collected by retro-orbital puncture at 0, 20 min, 40 min, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 h, samples were determined by LC-MS/MS, and plasma concentration-time data were analyzed by DAS 2.0 software to get the related pharmacokinetic parameters. The main pharmacokinetic parameters: area under curve (AUC), mean residence time (MRT), the biological half-life (t1/2) and the peak concentration (C(max)) of furosemide, were significantly increased at high altitude, the time to reach peak concentration (t(max)) and clearance (CL) was significantly decreased. This study found significant changes on the pharmacokinetics of furosemide under the special environment of high altitude. This finding may provide some references for clinical rational application of furosemide at high altitude.