ABSTRACT
A sensitive analytical method based on reversed microemulsion electrokinetic chromatography ( MEEKC) combined with on_line preconcentration technique was developed for the determination of polycyclic aromatic hydrocarbons ( PAHs ) in cosmetics. For six lipophilic PAHs analytes which are difficult to be separated under conventional conditions, three stacking techniques including large volume sample stacking ( LVSS) , dynamic pH junction and sweeping ( LVSS_DypH_sweep ) were combined to realize the efficient preconcentration and separation. Under the optimum conditions, including the microemulsion buffer with the composition of 2. 4%(w/w)SDS_0. 6% (w/w) octane_6. 6% (w/w)n_butyl alcohol_20 mmol/L NaH2PO4 ( pH 2 . 2 ) , HCB injection time of 20 s ( 16 kPa ) and sample injection time of 80 s ( 16 kPa ) , good enrichment effect was reached with the enrichment factors ranged from 25 to 80 , and the PAHs were analyzed successfully within 27 min. The developed method was used to analyze the PAHs in cosmetics. The recoveries ranged from 90 . 6% to 95 . 9%. The RSD values ( n=5 ) were less than 5 . 1%.
ABSTRACT
AIM To examined the effect of bFGF on the calcium influx in outer hair cells (OHCs) and its antagonistical effects with streptomycin. The aim of the study is to explore the mechanism of acute ototoxicity of streptomycin and antagonism of bFGF. METHODSE The OHCs of guinea pig were isolated using an enzyme machine methods and loaded with 10 ?mol?L -1 Fluo 3/AM for 30 min at 37℃,then cultured 60 min at room temperature. Individual Fluo 3 loaded OHCs were examined with a confocal microscope (ACAS Ultima, USA) using a 20? objective lens and linear scan mean. The fluorescent images, collected every 5 sec for 300 s, were stored in a computer. The fluorescent intensity of the images were analyzed by the software cooperated with the confocal microscope, and a function curve showing the change trend of fluorescent intensity with time was obtained. RESULTS The OHCs [Ca 2+ ] i hold steady within the process of normal extracellular liquid perfusion. OHCs [Ca 2+ ] i increased when perfused 100 mmol?L -1 high potassium media(10/11) and normal media containing 1 nmol?L -1 bFGF(9/9), but the OHCs [Ca 2+ ] i don't changes in high potassium free calcium media(7/7) and free calcium media containing 1 nmol?L -1 bFGF(8/8). After treated by 1 mmol?L -1 streptomycin, the OHCs [Ca 2+ ] i increased 0/12, 4/8 respectively when perfused high potassium media and bFGF media. And after treated by 1 nmol?L -1 bFGF, high potassium media make OHCs [Ca 2+ ] i increased more obviously and keeping longer time. After treated by 1 mmol?L -1 streptomycin, respectively, 0 1,1 and 10 nmol?L -1 bFGF make 4/11,6/9 and 12/12 OHCs [Ca 2+ ] i increasing when perfused high potassium media. CONCLUSION High potassium media and bFGF perfusion can result in increasing of OHCs [Ca 2+ ] i ,and OHCs [Ca 2+ ] i increase rooted in the calicum influx, there is synergic effects between high potassium and bFGF. The streptomycin can block the process of calcium influx induced by high potassium media and the block effects can be antagonized by bFGF, and the antagonistical effects have bFGF concentration dependence.
ABSTRACT
To evaluate the effect of bFGF on the calcium influx in SGCs and its antagonistical effect on streptomycin. The SGCs of guinea pig were isolated using an enzyme machine methods and loaded with 10?mol/L Fluo 3/AM for 30 min at 37℃,then cultured 60min at room temperature. Individual Fluo 3 loaded SGCs were examined with a confocal microscope (ACAS Ultima, USA) using a 20 x objective lens and linear scan mean.The level of SGCs[Ca 2+ ] i was steady within the process of normal extracellular liquid perfusion. SGCs[Ca 2+ ] i was increased when SGCs were perfused with 150mmol/L high potassium media(10/10) and normal media containing 1nmol/L bFGF(8/9), but the level of SGCs[Ca 2+ ] i did not change in high potassium free calcium media(9/9) and free calcium media containing 1nmol/L bFGF(10/11). After the treatment with 1 mmol/L streptomycin, the level of SGCs[Ca 2+ ] i was increased 1/11 and 5/12, respectively, when perfused high potassium media and bFGF media. And after being treated with 1nmol/L bFGF, high potassium media, SGCs[Ca 2+ ] i was increased more obviously and persisted for a longer time. After being treated with 1 mmol/L streptomycin, 0 1nmol/L, 1nmol/L and 10nmol/L bFGF, respectively, and 14/14 the level of SGCs[Ca 2+ ] i was increased 5/11, 9/12, and 14/14 when perfused high potassium media. High potassium media and bFGF perfusion could result in an increase of SGCs[Ca 2+ ] i ,and SGCs[Ca 2+ ] i increase was the result of calcium influx, and there was a synergic effect between high potassium and bFGF. Streptomycin could block the process of calcium influx induced by high potassium media, the blocking effect could be antagonized by bFGF, and the antagonistic effect was bFGF concentration dependent.