AIM: To study the changes of K + channels of outer hair cells in guinea pig cochlea with streptomycin ototoxicity. METHODS: Auditory brainstem responses (ABR) and whole-cell patch clamp techniques were used.RESULTS: (1) The body weight of guinea pigs with streptomycin ototoxicity decreased significantly; (2) The ABR threshold markedly increased in streptomycin group (Ⅱ,Ⅲ);(3)The number of dissociated outer hair cells of guinea pigs (Ⅱ,Ⅲ) was lower than that of control (Ⅰ); (4) Streptomycin decreased the Ca 2+ -sensitive K + currents and delayed outward K + currents distinctly; (5) There was no significant difference of K + currents between Ⅰ and Ⅱ/Ⅲ. CONCLUSION: These results suggest that the inhibition of K + channels is the basis of streptomycin ototoxicity, but not the direct reason for cell death.

Objective To observe the effect of tetraethylplyrazine(TMP) on outward K~+ channel of outer hair cells in guinea pig cochlea.Methods 60 guinea pigs were divided into 6 groups randomly in the experiment.Auditory brainstem response was used to monitor the change of ABR thresholds and patch clamp techniques to observe the effect of TMP on outward K~+ channel.Results TMP decreased the elevated ABR threshold caused by streptomycin. The TMP increased the amplitudes of calcium sensitive potassium channels (I_ K(Ca) ) and delayed outward potassium channels (IK) of outer hair cells of guinea pig cochlea.Conclusion The study indicates that TMP may act as a protective agent against ototoxicity of streptomycin. The amplitudes of I_ K(Ca) and IK of outer hair cells are increased by the TMP,suggesting the possible mechanisms of reducing ototoxicity.

AIM To analyze the mechanism of the adriamycin induced cardiomyopathy. METHODS The patch clamp technique in the whole cell recording was used to study the effect of adriamycin on L type calcium channel current( I Ca L ) in the isolated cardiomyocyte of the guinea pig. RESULTS The current voltage( I U ) curveshowed the bell shape in the control and in 0 1 mmol?L -1 adriamycin. Their peak potentials were about +10 mV. The amlitude of peak calcium current increased from (-0 93?0 05) nA to (-1 31?0 08) nA( P

Objective To investigate the change of CNP (C-natriuretic peptides) in patients with PCOS (polycystic ovary syndrome) undergoing in vitro fertilization-embryo transfer (IVF-ET) with GnRH-α longprotocol for controll ovarian hyper-stimulation(COH).Methods From March 2012 to September 2014,22cases patients with PCOS undergoing IVF-ET in the Reproductive Medical Center of the Center Hospital of JiangMen were selected as study group(Group 1),and 32 cases patients with normal ovarian reserve,the age younger than 35,and the number of oocytes retrieved more than 6 at the same period were selected as control group(Group 2).The level of serum CNP and estradiol(E2) on the day of human chorionic gonadotropin (HCG) and retrieving oocytes,the level of CNP and E2 in follicular fluid were analyzed.In additional,the levels of CNP and E2 in follicular fluid of different fertility and embryo quality were compared.Results (1) CNP and E2 on the day of HCG were significantly higher than that on the day of retrieving oocytes (CNPof Group 1:(107.21±78.55) μg/L vs.(73.01±55.99) μg/L,CNP of Group 2:(69.16±32.39) μg/L vs.(44.11±27.23) μg/L;E2 of group 1:(5231.38±1489.00) ng/L vs.(1985.52±662.54) ng/L,E2 of Group 2:(3678.45±969.57) ng/L vs.(1567.71±493.93) ng/L;t =2.968,2.752,8.147,14.567;P＜0.05).CNP and E2 on the day of retrieving oocytes and E2 on the day of HCG of Group 1 were higher than that of Group 2(t=2.866,2.227,2.173;P＜0.05).CNP in follicular fluid in Group 1 was higher than that in Group 2,but E2 of in follicular fluid in Group 1 was lower than that in Group 2 (t =2.244,-2.650;P＜0.05).(2) In Group 1,CNP and E2 in follicular fluid of normal fertility were lower than that of unnormal fertility,and E2 in follicular fluid of unnormal fertility were higher than that of no-fertility,and there were significant differences(t =-6.117,-2.374,2.760;P＜0.05).(3) In Group 2,only E2 in follicular fluid of unnormal fertility were higher than that of no-fertility,and there was significant difference(t=2.658,P＜0.05).(4) In 2 groups,CNP in follicular fluid of high-quality embryo were lower than that of non-high-quality embryo,and there was significant difference (t =-2.910,-2.029;P＜0.05).CNP in follicular fluid of non-high-quality embryo in Group 1 were higher than that in Group 2,but E2 in follicular fluid of non-high-quality embryo in Group 2 were higher than that in Group 1,and there were significant differences (t =2.141,-2.009;P ＜ 0.05).Conclusion There are differences in the change of CNP in the patients with PCOS and non-PCOS,and there are some deficiencies of the first meiosis in the patients with PCOS.

Objective:To research the correlation between the cobamamide photodegradation products in the visible light area at different wavelengths and the photodegradation rate intensity. Methods:The 40-minute illumination experiment was conducted for co-bamamide reference solution respectively at the wavelength of 400 nm,450 nm,500 nm,550 nm,600 nm,650 nm and 700 nm under the illumination of 50 Lx,100 Lx,200 Lx,300 Lx,400 Lx and 500 Lx,respectively. An HPLC method was used to detect the cobam-amide content after the irradiation, the contents and proportions of hydroxocobalamin and adenosine (two photodegradation products) were calculated and the two photodegradation products were confirmed by mass spectrum. Results:The main photodegradation products of cobamamide (impurity 1,adenosine and hydroxocobalamin) had the similar photodegradation tendency. Within the scope of 50 Lx-200 Lx,the illumination intensity affected the concentration ratio of hydroxocobalamin and adenosine obviously. Within the scope of 200 Lx-500 Lx,the illumination intensity showed smaller effect. Under the different wavelengths and photodegradation rate intensity, the content of hydroxocobalamin was higher than that of adenosine under the same experimental condition.Conclusion:This paper re-searched the cobamamide photodegradation products in the optimum dark condition. The method is accurate and reliable,which can be used for the control of photodegradation related substances of cobamamide.

Objective To screen the most suitable medium for Brucella drug susceptibility test, and observe the resistance of human derived Brucella to different antibiotics. Methods Totally 180 strains of Brucella isolated from 25 provinces (municipalities, autonomous regions) in recent years were taken as observation objects. Mueller-Hinton ( MH ) agar , MH blood agar and Brinell agar were used to carried out the drug susceptibility test in vitro, and to compare the results of drug susceptibility test of different medium; the most suitable Brucella drug susceptibility test medium was used to detect the resistance of human derived Brucella to Doxycycline, Rifampicin, Streptomycin, Levofloxacin, Moxifloxacin, Ceftriaxone sodium, Co-trimoxazole and Amoxicillin/Clavulanic acid by K-B drug sensitive paper, and to observe the formation of antibacterial ring around the drug sensitive paper. Results The growth of Brucella on the MH agar and MH blood agar were slower than that on the Brinell agar, and the antibacterial rings were not obvious. All the 180 strains of Brucella were sensitive to seven antibiotics such as Doxycycline, Rifampicin, Streptomycin, Levofloxacin, Moxifloxacin, Ceftriaxone sodium, and Amoxicillin/Clavulanic acid; and 70 strains of Brucella were resistant to Co-trimoxazole, accounting for 39％ (70/180); Brucella strains resistant to Co-trimoxazole were found in 21 provinces. Conclusions Brinell agar is the most suitable medium for Brucella susceptibility test. The human derived Brucella is resistant to Co-trimoxazole; the resistant strains are distributed in 21 provinces ( municipalities , autonomous regions ) . It is recommended that relevant departm ents of the province ( municipalities , autonomous regions ) carry out epidemiological investigations on the resistance of Brucella, and strengthen the monitoring of drug resistance in clinical drugs of brucellosis patients.

Objective: To analyze the status of domestic surgical treatment of synchronous peritoneal carcinomatosis from colorectal cancer in China. Methods: Clinicopathological data of patients who underwent surgery from October 2003 to October 2018 in 16 domestic medical centers was retrospectively analyzed. Excel database was created which covered 77 fields of 7 parts: baseline information of patients, laboratory tests, imaging tests, chemoradiotherapy information, intra-operative findings, postoperative pathology and follow-up data. The Wilcoxon rank-sum test was used for comparison of the measurement data between groups. The χ² test was used for comparison of the categorical data between groups. The survival curve was calculated by the Kaplan-Meier method. Results: Of the 1 003 patients, there were 575 male and 428 female patients with the age of (58.5±14.1) years (range: 18 to 92 years). In a total of 920 patients, the carcinoma of sigmoid colon was performed in 292 cases (31.8%) with the highest ratio. The proportion of patients with liver metastasis and lung metastasis were 27.9% (219/784) and 8.3% (64/769). Preoperative detection of carcino-embryonic antigen level was the most common method in China (87.74%, 880/1 003), and the positive rate was 64.5% (568/880). The correct rate of preoperative imaging tests was 40.7% (280/688). The ratio of peritoneal carcinomatosis index (PCI) scores between 0 and 10 was the highest (59.6%, 170/285). Two hundred and sixty-two (27.0%) patients were performed by totally laparoscopic operation in 971 patients. The resection of primary tumor was performed in 588 of the 817 patients (72.0%). In a total of 457 cases, 253 (55.4%) patients were performed cytoreduction which group scored completeness of cytoreduction (CCR) 0. The postoperative hyperthermic intraperitoneal chemotherapy was implemented in 70 of the 334 cases (21.0%). Among 1 003 cases, 562 cases (56.03%) had complete follow-up data and the median overall survival was 15 months. The primary tumor resection and the CCR scores were affected by the PCI scores. The patients underwent primary tumor resection (187/205 vs. 26/80, χ²=105.085, P=0.000) and the patients were performed cytoreduction which scored CCR 0 or CCR 1 (162/204 vs. 8/78, Z=-10.465, P=0.000) had significant difference between the groups of PCI<20 and ≥20. There was a close correlation between the surgical method and the CCR scores (Z=-3.246,P=0.001).When the maximum degree of tumor reduction was planned, most surgeons would choose laparotomy. The overall survival time was longer in patients with primary tumor resection (P=0.000). The median survival time was 18.6 months in the group of primary tumor resection. Conclusions It is difficult to diagnose the synchronous peritoneal carcinomatosis from colorectal cancer before the operation. Primary tumor resection has an obvious effect to prolong the survival time. It is necessary to standardize the treatment of peritoneal metastasis.