MELAS syndrome(mitochondrial myopathy encephalophathy with lactic acidosis and stroke-like episodes),as one of the most common diseases in mitochondrial encephalomyopathies,is characterized by highly variable manifestations.So,more and more people come to realize the importance of molecular basis of MELAS.This review took the commonest mtDNA point mutation(A3243G) for example to overview its molecular biological mechanism,test strategy and recent progress of study on MELAS syndrome.

There is a long history of Toad venom in the treatment of cancer in China.Bufalin,extracted from Toad venom,is one of the biologically active compounds of anticancer.We elaborate the molecular mechanism of bufalin on anticancer activity from several aspects such as inducing cell apoptosis and differentiation,inhibitting cell proliferation and angiogenesis,enhancing the sensitivity of chemotherapeutics,which can provide the basis for in-depth study of Toad venom and its development and clinical medication.

OBJECTIVE To investigate the resistance to ?-lactam antibiotics and meropenem of non-ESBLs-producing Escherichia coli isolates.METHODS Non-ESBLs producers of E.coli isolates were detected by CLSI phenotypic confirmatory test,and susceptibility of these isolates to ?-lactam antibiotics and meropenem was tested by agar dilution method.RESULTS The resistance rate of these isolates to ampicillin,cefazolin and cefoxime was more than 60% and that to cefoperazone-sulbactam,cefmetazole and cefepime was 19.2%,23.8% and 31.8%,respectively,but most were susceptible to cefotaxime,ceftazidime,and meropenem.CONCLUSIONS The most isolates of non-ESBLs-producing E.coli are resistant to ampicillin and to the first and second generation cephalosporins,but they are susceptible to meropenem and the third generation cephalosporins.

Objective The ‘Spider Track Map (Fuwai)’is an innovative tool for comprehensive evaluation of scientific research performance.It was developed jointly by the Science & Research de partment and Medical Research & Biometrics Center in Fuwai Hospital.This tool aims to evaluate the development of scientific performances in 3 consecutive years of targeted departments,which will be considered to assess the technological competitiveness of each department.Methods The key variables were the number of projects,funding,awards,publications and patents during the last three years.After standardization,the weighted sum of those variables was calculated.Then the ‘Spider Track Map (Fuwai) ’ could be generated and the evaluation conclusion would be obtained after stratification.Results The ‘Spider Track Map (Fuwai)’ method had been used to evaluate the scientific research performance in 2015.The excellent research departments had been successfully elected and rewarded.Conclusions Beside the excellent department election,the method can also identify different feature of performance including improved,retrogressive,high efficiency or no changes.This multidimensional tool provides the reference to administrators for scientific commendation and reward and also the guid ing and alerting for specific department.

Objective To investigate the adhesion levels in uropathogenic Escherichia coli with various degree of drug resistance.Methods One hundred strains of Escherichia coli isolated from urine specimen were collected from patients admitted to 4 Grade A tertiary hospitals in Tianjin during March 2012 to October 2015.Escherichia coli were divided into drug sensitive group and drug resistant group by drug sensitivity tests with 50 strains in each group.The expressions of fimH,fimA,fimB genes of type I fimbriae and papA,papB,papC,papGII genes of P fimbriae were detected by polymerase chain reaction(PCR)and real-time fluorescence quantitative RCR (RT-PCR),respectively.Adhesion ability of type I fimbriae and P fimbriae were tested by yeast cell adhesion test and erythrocyte agglutination test.Chi square test and t(Z) test were used to analyze the data.Results The positive rate of papGII in drug resistant group (42.0%) was significantly higher than that in the drug sensitive group (16.0%)(χ2 =8.208,P <0.05),while there were no significant differences in the positive rates of fimH,fimA,fimB,papA,papB and papC genes between two groups(all P >0.05).The expression levels of fimH,fimB and papC genes in the sensitive group were higher than those in the resistant group(Z =3.427,t =5.182 and 8.120,all P <0.05).The adhesion ability of strains carrying type I fimbriae in sensitive group was stronger than that of resistant group (χ2 =5.769,P <0.05).Conclusions The decline in adhesion ability of type I fimbriae in drug resistant E.coli strains is possibly associated with the adaptive cost of bacteria,the transcription and deficiency of other genes encoded by fim and pap gene cluster will also affect the adhesion function of type I pili and type P pili.

Objective To investigate the effect of intrathecal nerve growth factor (NGF) on lidocaineinduced neurotoxicity to the spinal cord in rats.Methods Thirty healthy male Sprague-Dawley rats,aged 8-10 weeks,weighing 250-300 g,were randomly divided into 5 groups (n =6 each) using a random number table:control group (group C),sham operation group (group S),lidocaine-induced neurotoxicity group (group L),normal saline group (group NS) and NGF group (group NGF).A catheter was inserted at L4.5 interspace into the epidural space in S,L,NS,and NGF groups.One day after surgery,20％ lidocaine 20 μl was injected intrathecally.At 24 h after lidocaine injection,normal saline 20 μl and NGF 10 μg (20 μd) were injected intrathecally in NS and NGF groups,respectively,once a day for 7 consecutive days.The tail flick latency (TFL) to a thermal nociceptive stimulus was measured on 1,3,5 and 7 days after lidocaine injection.The animals were sacrificed after the behavioral test was completed at 7 days after lidocaine injection,and the lumbar segments of the spinal cord were removed to detect the neuronal apoptosis (using flow cytometry) and caspase-3 mRNA expression (by RT-PCR).Results Compared with group C,the TFL was significantly prolonged at 1-7 days after lidocaine injection in L and NS groups and at 1-5 days after lidocaine injection in group NGF,the apoptosis rate was increased in L,NS and NGF groups,and caspase-3 mRNA expression was up-regulated in L and NS groups,and no significant change was found in the parameters mentioned above in group S.Compared with group L,the TFL was significantly shortened at 5 and 7 days after lidocaine injection,the apoptosis rate was decreased,and caspase3 mRNA expression was down-regulated in NGF group,and no significant change was found in the parameters mentioned above in group NS.Conclusion Intrathecal NGF can reduce lidocaine-induced neurotoxicity to the spinal cord in rats and inhibition of caspase-3 mRNA expression is involved in the mechanism.

OBJECTIVE: To prepare ethacridine lactate solution and to evaluate its quality.METHODS: The solution was prepared with ethacridine lactate as principal components and sterilized by steam sterilization.HPLC method was used for the determination of ethacridine.Calesil ODS column was used with mobile phase consisted of methanol-acetonitrile-0.05% sodium laurysulfonate (pH=3.0,20 ∶ 20 ∶ 60) at detection wavelength of 270 nm.The column temperature was set at 30 ℃ and injection volume was 10 ?L.The effect of sterilization on the content of preparation was determined.RESULTS: The preparation assumed as yellow transparent solution.The linear range of ethacridine was 5～50 ?g?mL-1(r=0.999 9) with an average recovery of 101.47% (RSD=1.32%,n=9).The content of ethacridine in the solution was not changed after sterilization.CONCLUSION: The quality of prepared ethacridine lactate solution is up to the standard.

Object To compare the contents of chlorogenic acid in the different processed crude drugs of Lonicera fulvotomentosa Hsu et S.C. Cheng. Methods The contents of chlorogenic acid were deter mined by HPLC. Chromatographic conditions included Hypersil C 18 column and the mobile phase consisting of a mixture of acetonitrile 0 4% phosphoric acid (13∶87). Chlorogenic acid was detected at 327 nm wavelength. Results The contents of chlorogenic acid were 0 54%, 0 81%, 0 57% in the sun cured flower bud, white bloom, gold flower in L. fulvotomentosa and 2 14%, 1 65%, 2 04% in the steaming sun cured crude drugs, respectively. Conclusion The contents of chlorogenic acid in the steaming sun cured crude drugs are higher than those in the sun cured crude drugs.

Objective To compare radiation dose and image quality between prospective electrocardiograph(ECG)-triggered axial seau and retrospective ECG-gated helical scan in coronary 64-slice CT angiography(CTA).Methods Seventy-seven consecutive patients[group A.Average body mass index (BMI):24.6,heart rate＜70 bpm]underwent 64-slice CTA using prospective ECG-triggered axial scan protocol(120 kV,mA tailored to BMI).For each patient,the simulated radiation dose using retrospective ECG-gated scan protocol without ECG-driven X-ray current modulation technology was calculated and recorded at sanle kV and mA.Retrospective ECG-gated scan protocol was performed on 30 consecutive patients in another group(group B.Average BMI:23.9,heart rate＜70 bpm).The image quality was blindly evaluated between group A and B(paired t-test was used and P＜0.05 as a significant difference).Results There Was a significant difference(t=18.50,P＜0.01)between radiation dose of group A (3.37 mSv)and that of group B(18.13 mSv),decreased by 81.4%.The image quality of group A could fulfill clinical diagnostic needs.The average radiation dose of using simulated helical scan without optimization was 17.29 mSv,which wag similar to that of group B(18.13 mSv)(t=0.87,P＞0.05).Condusion Prospective ECG-triggered axial scan in 64-slice coronary CTA Call significantly reduce radiation exposure and the image quality can fulfill clinical diagnostic needs.

Objective To evaluate the effect of spectral CT monochromatic imaging on the detection of hepatic tumors. Methods Forty-two patients with hepatic tumors (14 patients with hepatocellular carcinoma, 12 patients with metastatic tumor, 16 patients with hemangioma) underwent CT spectral imaging. During arterial phase, portal phase and venous phase, 140 kVp polychromatic images and 70 keV monochromatic images were obtained. Paired-sample t tests were used to compare the image quality score,liver noise and tumor-to-liver contrast-to-noise ratio (CNR) between the two image data sets. The detection rates of various tumors during each phase were compared. Results The image quality scores of various tumors during three phases were (4. 30 ± 0. 25) and (3.63 ± 0. 22) averagely for the 70 keV and 140 kVp images. The liver noises were (8. 82 ± 0. 82) and ( 10. 66 ± 1.10) , and the CNRs were 5.39 and 3. 89,respectively. The image quality score, the liver noise and the CNR of 70 keV images were significantly greater than those of 140 kVp images (P ＜0. 05 ). The detection rates of various tumors during each phase were higher with 70 keV images (78％-100％) than with 140 kVp images (65％-96％), except the hepatic metastatic tumors and the hepatic hemangiomas during the arterial phase. The detection rate was more increased for the small lesions less than 1 cm (57％-100％ vs. 14％-91％ ). Conclusion By substantially improving the image quality and increasing the tumor-to-liver conspicuity, the 70 keV monochromatic imaging of spectral CT improves the detection of hepatic tumors and is more sensitive for the detection of small lesions.