Aim To observe the effect of three steroidal saponins on the M-cholinoceptor density of cultured rat myocardiac cells. Methods The time course of M-cholinoceptor density was observed and diosgenin (DIO),timosaponin aglycone (ZMS,S-configuration) and XMS,a stereoisomeric compound of ZMS in C-25 methyl group,R-configuration) were added to the culture medium from the 12th day of culture at three final concentration of 10~(-7),10~(-6) and 10~(-5) mol?L~(-1),and the M-cholinoceptor density was measured on the 16th day with radioligand binding assay. Results The density of M-cholinoceptor increased gradually at the beginning of culture,reached a plateau at 4～10 days,and then dropped gradually. On the 16th day of culture,the M-cholinoceptor density was about 60% of the plateau value.The up-regulation effect of ZMS on the density of cultured rat myocardiac cells on the 16 th day was only significant at a final concentration of 10~(-5) mol?L~(-1). On the contrary,XMS was effective even when its final concentration was as low as 10~(-7) mol?L~(-1). DIO showed no effect on the M-cholinoceptor density at any of its three concentration. Conclusion The above results indicate that XMS with lower concentration showed similar effect on the M-cholinoceptor density of cultured mylcardiac cells as that of ZMS with more higher concentration.

Objective To investigate the effects of aging on the brain stem speech encoding in spontaneous post-menopause women.Methods There were twenty post-menopause women with normal hearing for test and twenty ovariectomized women with normal hearing for contrast.Speech-evoked auditory brainstem response (speech-ABR) was used.The speech syllable /da/ as stimulus sound was transmitted to right ear by the insert earphones in speech-ABR test.Results Response waves of speech-ABR in ovariectomized women were similar to those in post-menopause women, which contained the onset response (peak V and A), the transition (peak C), the frequency following responses (peak D, E and F) and the offset response (peak O).The characteristics of speech-ABR's peak latency and magnitude were similar between the two groups.Except that the bilateral ovariectomized women had a shorter latency of waves O for the transient response (P<0.01), the larger amplitude of peak F for the periodic portion than post-menopause women (P<0.05).No significant differences were found in the amplitude the latency of the other waves, and V/A slope between bilateral ovariectomized women (0.21±0.10 μV /ms)and post-menopause women (-0.20±0.09 μV/ms) was similar and had no statistical significance (P>0.05).After the combination of ovariectomized women and post-menopause women, the age of these subjects was positively correlated with the latency of O wave (P<0.05).Others had no correlation with age in the amplitude and latency of the waves of speech-ABR.Conclusion Aging does not affect on brain stem speech encoding in spontaneous post-menopause women.

Objective: To investigate an effect on speech recognition after bilateral cochlear implants(CI) simultaneously. Methods: Nine subjects who underwent bilateral CI operation simultaneously in Peking Union Hospital in 2007 were assigned as bilateral group, another 9 subjects with unilateral CI were chosen as unilateral group according to the age, gender, duration of deafness. Hearing threshold, speech recognition of phrases, disyllabic words, single word in quiet and noise environment were calculated, respectively. Three different sound source positions were set up to simulate the three effects of binaural hearing (head shadow, binaural redundancy and binaural squelch) in noise environment. The speech signal intensity was 70 dBSPL, the signal to noise ratio (SNR) was 0 dB, + 4 dB, + 8 dB, and the speech recognition of phrases were examined in bilateral CI group. All the data was analyzed by SPSS 19.0 software. Results: In quiet environment, the average aid-hearing threshold was significantly reduced as (7.2±3.0)dB in bilateral CI group compared to unilateral CI group(P<0.05). However, the speech recognition of phrases, disyllabic words, and single word in quiet and noise environment did not show significant differences between bilateral CI and unilateral CI groups (P>0.05). In the testing under noise environment, the speech recognition of bilateral CI group was significantly higher than that of unilateral CI group (P<0.05). In the estimation of noise environment (SNR=+ 8), the phrase test and speech recognition of head shadow model in bilateral groups were significantly better than that of unilateral group (P<0.01). Further, bilateral CI group showed statistical significances in binaural redundancy and binaural squelch models(P<0.01), there was statistically significant were also found difference between two groups (P<0.01); Bilateral CI group did not reveal significant difference compared with unbilateral CI group in binaural squelch model(P>0.05). Under different signal-to-noise ratio (SNR=+ 8, + 4) noise environment, all the three given models in bilateral CI group show higher signal-to-noise ratio, higher speech recognition rate (Independent-Samples t test, P<0.01). In addition, head shadow model presented negative influences on speech recognition rate compared with binaural redundancy and binaural squelch model by SNR(P<0.05). SNR influences on binaural redundancy and binaural squelch model were almost identical, F=0.371, P=0.549. Conclusion The subjects who underwent simultaneous bilateral cochlear implantation could significantly reduce aid-hearing threshold, and greatly improve the speech recognition of phrases, disyllabic words, and single word under noise environment.