ObjectiveTo establish a novel rapid detection method based on PCR-single-strand-conformational polymorphism (PCR-SSCP) to determine mutation of streptomycin-resistance associated rpsL and rrs genes in isolates of Mycobacterium tuberculosis (MTB).MethodsStreptomycin-resistance of 112 MTB isolates was detected using the routine drug susceptibility test,and a special PCR-SSCP assay was established.The mutations of rpsL and rrs genes in streptomycin-resistant MTB isolates were detected by PCR-SSCP and PCR direct sequencing (PCR-DS) ; the results from two techniques were compared.Results All isolates had both rpsL and rrs genes.Fifty-two isolates (46.4％) were streptomycin susceptible,in which only 1 isolate showed abnormal PCR-SSCP fragments from rrs gene,and the specificity of PCR-SSCP was 98.1％ (51/52).Sixty isolates (53.6％) were streptomycin-resistant,in which 46 (76.6％) and 11 ( 18.3％ ) isolates presented the abnormal PCR-SSCP fragments of rpsL and rrs gene,respectively.One streptomycin-resistant isolate showed abnormal PCR-SSCP fragments from both rpsL and rrs genes.The sensitivity of PCR-SSCP was 93.3％ (56/60).ConclusionThe PCR-SSCP that established in this study is a specific and sensitive method for rapid detection of the streptomycin-resistance associated mutations in rpsL and rrs genes of MTB.

Objective To analyze and compare the mutations in two different regions of the katG gene and study the relevance of Mycobacterium tuberculosis isoniazid-resistance and mutations in two different regions of the katG gene. Methods Fifty-three INH-resistant Mycobacterium tuberculosis strains isolated in cultures of sputum samples obtained from Zhejiang province were analyzed. PCR was used to amplify two regions of the katG gene (GenBank accession no. U06258) region 1 (from codon 1 to codon 150) and region 2 ( from codon 227 to codon 470) which were then sequenced in order to identify mutations. Results Three strains resistant to INH did not contain mutations in either region. Fourteen strains carried mutations in region 1. Among them 5 strains barbered deletions, and showed high-level resistance to isoniazid. Five strains had mutations only in region 1. Region 2 carried multiple point mutations, especially at codon 315, and there were S315 N ( AGC→AAC ) substitution in 18 of those cases. The frequency of mutations in the katG S315 of high-level INH-resistance isolates ( 84. 4%, 27/32) was significantly higher than those of low-level INH-resistance isolates( 15.6%, 5/32 ), there was statistically significant difference (x2 = 30. 25, P ＜ 0. 01 ).katG S315 mutations in high-level INH-resistance frequency (84. 4%, 27/32) was significantly higher than the other mutations of katG gene of high-level INH-resistance frequency (27. 7%, 5/18 ), there was significant difference (x2 = 16.02, P ＜ 0. 01 ). The analysis of region 2 allowed INH resistance to be diagnosed in 84. 9% of the strains. Five strains had mutations only in region 1 ,which allowed the proportion of INH-resistant strains identified to be increased to 94. 3%. Conclusions The number of mutations at codon 315 was high. Mutation type and location closely related with drug resistance and the analysis of region 1 resulted in a 9. 4% increase in the rate at which mutations were identified.

Ophthalmic microsurgery has its own characteristics: high precision , complicated operation , and long learning curve.It is important for young ophthalmologists to master the basic operation skills through standardized and systematic training during graduate studies .The teaching method , integrating theoretical teaching , animal operation and simulative ophthalmic surgery training , have important meanings in promoting the post-graduate students to master the practical and correct ophthalmic microsurgery technique . The aim of this study was to introduce the curriculum design and practice , and to evaluate the model through the examination scores .

Objective To observe the effect of small-interfering RNA(siRNA) targeting c-Met,the receptor of hepatocyte growth factor(HGF),on the proliferation of human lens epithelial cells(LECs).Methods siRNA was transferred into LECs cultured in vitro by HiperFect Transfection Reagent.Real-Time PCR was applied to observe the expression of c-Met mRNA in LECs after gene transfer,and MTT assay was used to detect the proliferation of LECs induced by HGF.Results The expression of c-Met mRNA in LECs was significantly decreased in the experimental group,compared to that in the controls(P<0.01).Proliferation of LECs induced by HGF was inhibited,compared with the single HGF stimulated group(P<0.01).Conclusion The RNA interference targeting c-Met can effectively inhibit the expression of c-Met mRNA,and the proliferation of LECs induced by HGF.

Objective To evaluate the effect of sevoflurane preconditioning on the expression of metabotropic glutamate receptor type Ⅱ( mGluRⅡ) during focal cerebral ischemia-reperfusion ( I∕R) in rats. Methods Forty-eight clean-grade healthy male Sprague-Dawley rats were divided into 3 groups (n＝16 each) using a random number table method: sham operation group ( group S), cerebral I∕R group (group I∕R) and sevoflurane preconditioning group (group Sev). Rats were anesthetized with 10% chloral hydrate 3 ml∕kg. Focal cerebral I∕R was produced by occlusion of the right middle cerebral artery for 2 h fol-lowed by 24 h reperfusion. In group Sev, 2. 7% sevoflurane was inhaled for 1 h and 24 h later focal cerebral I∕R was produced. At 24 h after reperfusion, neurological deficit was scored, the cerebral infarct size was determined by TTC staining, the cell apoptosis in ischemic penumbra was observed by TUNEL, IκB-α ex-pression was detected by Western blot, and mGluRⅡexpression was determined by immunofluorescent stai-ning. The apoptosis rate was calculated. Results Compared with group S, the neurological deficit score, cerebral infarct size and apoptosis rate were significantly increased, the expression of mGluRⅡwas up-regu-lated, and the expression of IκB-α was down-regulated in I∕R and Sev groups ( P＜0. 05). Compared with group I∕R, the neurological deficit score, cerebral infarct size and apoptosis rate were significantly de-creased, the expression of mGluRⅡwas down-regulated, and the expression of IκB-α was up-regulated in group Sev (P＜0. 05). Conclusion Sevoflurane preconditioning reduces focal cerebral I∕R injury through inhibiting the expression of mGluRⅡ in rats.