ABSTRACT
Objective To observe auditory brainstem response evoked at different electrode positions adopting electrode slices .Methods The ABRs of 12 normal guinea pigs (24 ears)were recorded by two methods using clicks as stimulation .Active electrode was positioned at the vertex while the ground electrode at the nose .The reference e‐lectrode was placed on bilateral pinnas or mastoids .Then observe waveforms ,response thresholds (RT) ,peak la‐tencies(PL) and inter-peak latencies (IPL)of ABR .Results No significant difference were observed in the RT ,Ⅰ ,Ⅱand Ⅲ PL ,Ⅰ - Ⅲ IPL of ABR between the two methods(P>0 .05) .When stimulation was decreasing and with the reference electrode slices placed at bilateral pinnas ,waveⅡpeak was stable and discernable of ABR record‐ings across twenty -four ears of guinea pigs .The amplitude decreased more slowly than any other waves ,and dis‐appeared at the last .While reference electrode slices were placed on bilateral mastoids ,the amplitude of wave Ⅲ de‐creased more slowly than any other waves except wave Ⅳ ,and disappeared at lost .Ⅱ - Ⅲ ,Ⅲ - Ⅳ IPL became shorter .These two positions both recorded amplitude higher and PL advanced for wave Ⅳ as the stimulation de‐creased by 20 to 40 dB nHL ,and Ⅲ - Ⅳ IPL became shorter .This phenomenon was more obvious when reference electrode was placed at mastoid .Conclusion Wave Ⅱwas more stable and discernible with reference electrode placed at the bilateral pinnas .Therefore wave Ⅱ recorded by this way can be a new method to record the ABR threshold of g uinea pig s .
ABSTRACT
Objective To compare the characteristics between two kinds of 40Hz auditory evoked potentials and provide suitable index for clinical auditory test of low-frequency. Methods The potentials including 40Hz auditory event related potential of middle latency response(40Hz AERP-MLR) and 40Hz auditory event related potential of early latency response(40Hz AERP-ELR) from window and vertex were recorded in guinea pigs. Results The common characteristics of the potentials were good frequency response,easy identification and lower responsive thresholds.Amplitude of 40Hz AERP-ELR was higher and threshold was lower than 40Hz AERP-MLR,especially 0.5kHz tone burst,which was (14.15?6.06)dBnHL.In vertex,the threshold of 40Hz AERP-MLR was (43.50?9.65)dBnHL,which was higher than that in round window(P
ABSTRACT
Objective To investigate the proliferation inhibition of chlorpromazine combined with taxol on Hep-2 cells (human laryngeal carcinoma cell line) and the effects on cell cycle progression. Methods Hep-2 cells at logarithmic growth phase were divided into taxol groups(3.0,6.0 and 12.0 mg?L-1),chlorpromazine(12.0 mg?L-1) comined with taxol (4 mg?L-1)group and control group (100 mL culture fluid).MTT and flow cytometry were used to detect the proliferation inhibition rates of Hep-2 cells in various groups.Flow cytometry was also used to analyze the cell cycle progression of Hep-2 cells and apoptotic rate after administration.Results The proliferation inhibition rates in 3.0,6.0 and 12.0 mg?L-1 taxol groups were 14.0%,23.9% and 36.7%,respectively,there were significant differences between three groups(P