Resistance mechanism of Mycoplasma hominis to quinolones in Chengdu area / 中华检验医学杂志

Objective To detect the resistance of Mycoplasma hominis to quinolones in Chengdu area,explore resistance mechanism of topoisomerase gene gyrA, gyrB, parC and parE mutations associated with drug resistance and provide epidemiological data.Methods Mycoplasma hominis was identified by 16SrRNA gene sequencing technique and antibiotic susceptibility test was carried out by broth microdilution method.Resistance genes were amplified by PCR,whereas sequence alignment was analyzed by DNAMAN software and BLAST.Results Resistance rates of Mycoplasma hominis to ciprofloxacin, levofloxacin, moxifloxacin and gatifloxacin were 92.4%(61/66),87.9%(58/66),71.2%(47/66)and 66.7%(44/66),respectively.Totally 45 strains with different susceptibility to quinolones were screened for amplification and sequencing of topoisomerase genes, of which, 31 strains resistant to moxifloxacin and gatifloxacin harbored GyrA S153L amino acid mutation, 68.9%(31/45), 41 strains resistant to ciprofloxacin and levofloxacin harbored ParC S91I amino acid mutation, 91.1%(41/45).In addition, a new amino acid substitution of ParE A463S was found in 2 high-level resistant strains.No amino acid change was found in GyrB.Conclusions Resistance of Mycoplasma hominis to quinolones is closely associated with amino acid changes caused by mutations in gyrA and parC genes.Different quinolones have different targeting roles and high level resistance is associated with multiple gene mutations.

Ki-67 and DNA topoisomerase Ⅱ a predict survival in patients with primary hepatocellular carcinoma after liver transplantation / 中华肝胆外科杂志

Objective To investigate whether Ki-67 and DNA topoisomerase Ⅱ α (Topo Ⅱ α) are effective prognostic markers in patients with primary hepatocellular carcinoma (HCC) after liver transplantation.Methods This retrospective cohort study included 105 patients with HCC who underwent liver transplantation in a single center from 2001 to 2012.The demographic features,clinicopathological data,expressions of Topo I c and Ki-67 as detected by immunohistochemistry.The long-term survival and the potential prognostic factors,together with standard histologic parameters,were analyzed by univariate and multivariate analyses.Results A positive correlation was found between Topo II α and Ki-67 levels in HCC (r ＝ 0.469,P ＜ 0.01).Multivariate analyses showed that Ki-67 was an independent prognostic risk factor of recurrencefree survival (HR ＝ 2.296,P ＜ 0.05).The 5-year overall survival rate was related to tumor size (HR ＝ 1.743,P ＜ 0.05),AFP (HR ＝ 2.291,P ＜ 0.05),histological grade (HR ＝ 0.283,P ＜ 0.01),and high expressions of Ki-67 (HR ＝ 1.977,P ＜ 0.05) and Topo Ⅱ α levels (HR ＝ 1.883,P ＜ 0.05).The KaplanMeier analysis showed that there was a significant difference in the 5-year recurrence-free survival rate (40.4％ vs.57.6％) between patients with high and low expressions of Ki-67,which were significantly lower in the high Topo Ⅱ α expression patients (13.5％ vs.63.8％) (P ＜0.01).The 5-year overall survival rates were significantly lower in the high Ki-67 expression patients (12.7％ vs.61.1％,P ＜0.01) when compared with the low Ki-67 expression patients,which were significantly lower in the high Topo Ⅱ α-and Ki-67 expression patients (10.7％ vs.54.5％,P ＜0.01) than the low Topo Ⅱ α-or Ki-67 patients.Conclusions Ki-67 was associated with recurrence and metastasis in patients with primary hepatic carcinoma after liver transplantation.High expression of both Ki-67 and Topo Ⅱ α were associated with poor prognosis in these patients.

Tyrosyl-DNA phosphodiesterases: potential targets for cancer treatment / 药学学报

DNA topoisomerases-mediated DNA damages are generated from exogenous and endogenous effects, which need to be metabolized or repaired to maintain genome stability involving in many of repair enzymes. Tyrosyl-DNA phosphodiesterase 1 (TDP1) and tyrosyl-DNA phosphodiesterase 2 (TDP2) are two DNA repair enzymes discovered recently. TDP1 and TDP2 have the ability to hydrolyze the tyrosyl-phosphodiester bond of the phenol of tyrosine with 3'-and 5'-DNA end, respectively, which are contained in the metabolites of the damaged DNA mediated by topoisomerase 1 and topoisomerase 2, respectively. The abnormal activation and expression of TDP1 or TDP2 is the important reason for cancer development. Therefore, TDP1 and TDP2 have been regarded as potential targets in cancer therapy. In this review, we discuss the rationales of their potential as targets and development of their inhibitors together with topoisomerase poisons or DNA damaging agents.

Correlation between expression of TOP2A and HER2 signaling pathway in breast cancer / 西安交通大学学报(医学版)

Objective To study the correlation of expression of DNA topoisomerase Ⅱ alpha (TOP2A)with expressions of human epidermal growth factor receptor 2 (HER2)and phosphatase and tensin homolog (PTEN)and gene mutation of phosphatidylinositol 3-kinase (PI3K)in breast cancer so as to provide reference for prognosis of the cancer and evaluation of drug efficiency.Methods This study enrolled totally 96 breast cancer patients. Tumor specimens were resected.The gene expressions of TOP2A,HER2 and PTEN were analyzed using branched DNA-liquid-chip,and PI3K gene mutation was detected by xTAG-liquid-chip.Correlations between gene expressions and gene mutation were further explored by Spearman correlation analysis so as to clarify the relationship between TOP2A and HER2 signaling pathway gene.Results Co-expression of TOP2A and HER2 was strong,and TOP2A tended to be highly expressed in the presence of high expression of HER2 (P =0.01).The expression of PTEN was not significantly correlated with the expression of TOP2A,whereas the mutation of PI3K had a positive association with the high expression of TOP2A (P =0.004).Conclusion Anthracycline drug resistance factor TOP2A may be related to the critical factors of HER2 signaling pathway,suggesting that HER2 expression and PI3K mutation may be key factors in regulation of TOP2A expression,which would provide important evidence for chemotherapeutic resistance.

New molecular biologist perspective and insight: DNA topoisomerases production by recombinant DNA technology for medical laboratory application and pharmaceutical industry

DNA topoisomerases are essential enzymes that control the topological state of DNA replication during mitosis. These enzymes are classified based on their mechanisms and physical properties. During mitosis, superhelical DNA must be unwound or relaxed by DNA topoisomerases prior to a decoding step by DNA processing enzymes, such as DNA polymerase and RNA polymerase. By blocking the reaction of resealing the breaks in the DNA ultimately can result in cellular death. Compounds that inhibit the catalytic function of these enzymes can serve as potential anticancer agents. DNA topoisomerases are found in nature and used as high quality and well-validated targets for the screening of potential anticancer agents. Our current work focuses on determining potential anticancer agents from natural resources using DNA topoisomerases as the screening targets. Large scale production of these enzymes using recombinant DNA technology in our academic laboratory is utilised to avoid dependence on expensive commercially available enzymes. The in-house produced enzymes can also be used to enhance our research in the field of molecular medicine by providing an enzyme source that can be used to screen potential anticancer agents, and for other newly developed diagnostic and medical research projects in the near future as well as a step in moving our efforts into the industrial sector.

Ciprofloxacin non-susceptible Streptococcus pyogenes due to mutations in parC gene and its homology analysis / 中华检验医学杂志

Objective To investigate the resistant mechanism of Streptococcus pyogenes to ciprofloxacin and its homology.Methods Forty-eight isolates of Streptococcus pyogenes were collected from patients diagnosed with scarflet fever in districts of Beijing in March,2012 and MIC to ciprofloxacin and other 7 common antibiotics in clinic were detected by using blood M-H agar dilution method.Thirteen isolates,which have MICs≥4 mg/L against ciprofloxacin,were detected for mutations of Fluoroquinolone resistance genes gyrA,gyrB,parC,parE.At the same time,4 isolates,with MIC ≤ 0.25 mg/L against ciprofloxacin,were used for comparison.Homology analysis of 17 isolates from different areas of Beijing was performed by using the method of pulsed field gel electrophoresis.Results Sensitive rates of Streptococcus pyogenes to levofloxacin,ampicillin and penicillin were all 100％.The resistance rates to tetracycline,erythromycin and clindamycin were 91.7％ (44/48),91.7％ (44/48) and 89.6％ (43/48),respectively.MIC50 of ciprofloxacin,levofloxacin and moxifloxacin was 2 mg/L,1 mg/L and ≤ 0.25 mg/L,respectively ; MIC90 was 4 mg/L,2 mg/L and 0.5 mg/L,respectively.Of the 48 isolates of Streptococcus pyogenes,12 isolates showed the MIC at 4 mg/L,while one isolate has a MIC against ciprofloxacin at 8 mg/L,which isolated from Chaoyang district.Analysis of sequence of chromosome mediated fluoroquinolone resistance genes in those 13 ciprofloxacin non-susceptible isolates exhibited that there were 12 isolates that harbored Ser79Phe/Tyr mutation and 10 isolates harbored Ala121Val in parC gene.It is shown that one isolate contained Ser79Phe mutation in parC gene in the occurring of Ser371Leu mutation in parE gene for the first time,but there was no marked increase in ciprofloxacin MIC (MIC =4 mg/L).There were no mutations in gyrA and gyrB genes.The PFGE results demonstrated that the 17 tested isolates could be divided into 7 clones.The clone A isolates from Chaoyang,Daxing,Fengtai,Shunyi and Shijingshan district have a MIC ≥ 4 mg/L against ciprofloxacin,which covered 69.2％ of all MIC ≥4 mg/L isolates.The clone C isolates from Huairou district were MIC ≥4 mg/L isolates.B,D,E,F and G clones isolates come from different districts.Conclusions The mutation of parC gene was the main reason that contribute to the slightly increase of ciprofloxacin MIC in Streptococcus pyogenes isolated from Beijing.The PFGE analysis showed that there was a small scale prevalence caused by the infection of Streptococcus pyogenes in some districts.

Differential in vitro activity of the DNA topoisomerase inhibitor idarubicin against Trypanosoma rangeli and Trypanosoma cruzi

In this study the effect of eight DNA topoisomerase inhibitors on the growth Trypanosoma rangeli epimastigotes in cell culture was investigated. Among the eight compounds tested, idarubicin was the only compound that displayed promising trypanocidal activity with a half-maximal growth inhibition (GI50) value in the sub-micromolar range. Fluorescence-activated cell sorting analysis showed a reduction in DNA content in T. rangeli epimastigotes when treated with idarubicin. In contrast to T. rangeli, against Trypanosoma cruzi epimastigotes idarubicin was much less effective exhibiting a GI50 value in the mid-micromolar range. This result indicates that idarubicin displays differential toxic effects in T. rangeli and T. cruzi. Compared with African trypanosomes, it seems that American trypanosomes are generally less susceptible to DNA topoisomerase inhibitors.

Study on the resistance-related genes of Shigella sonnei with decreased susceptibility to fluoroquinolones / 中华传染病杂志

Objective To investigate the resistance-related genes of Shigella sonnei with decreased susceptibility to fluoroquinolones.MethodsA total of 131 strains of Shigella sonnei were analyzed for their antimicrobial susceptibility.Mutations within the quinolone resistance determining regions (QRDR) of gyrA and parC were detected by polymerase chain reaction (PCR) and PCR products were then sequenced. Meanwhile, the plasmid-mediated quinolone resistance (PMQR) genes,qnr and aac(6')-Ib-cr were screened by PCR.ResultsResistance rates of 131 Shigella sonnei isolates to nalidixic acid,tetracycline,ampicillin and trimethoprim-sulfamethoxazole were 100.0％,93.9％,93.2％ and 92.8％,respectively.All strains were susceptible to norfloxacin,ciprofloxacin,levofloxacin,while 94％ nalidixic acid-resistant Shigella sonnei strains showed reduced susceptibilities to fluoroquinolones.All of nalidixic acid-resistant Shigella sonnei strains presented a single mutation at codon 83 (Ser→Leu) of gyrA genes,but no mutations were detected in parC gene.And PMQR genes qnr and aac (6’)-Ib-cr were not detected.Conclusions The nalidixic acid-resistant Shigella sonnei strains with reduced susceptibility to fluoroquinolones are common in the clinical practice,which may mainly due to a single mutation at codon 83 (Ser→Leu) of gyrA genes.

Antioxidant and antitopoisomerase activities in plant extracts of some Colombian flora from La Marcada Natural Regional Park

Many plants have been used to treat some diseases and infections since time immemorial, and this potential has been exploited by the pharmaceutical industry in the search of new analgesic, anticarcinogenic and antimicrobial agents, among other active agents. in order to contribute with bioprospection studies on the Colombian flora, 35 extracts from 13 plant species belonging to seven families (Apocynaceae, Cactaceae, Costaceae, Eremolepidaceae, Passifloraceae, Solanaceae and Urticaceae) were collected from La Marcada Natural Regional Park (LMNRP), Colombia. Dichloromethane, n-hexane and aqueous-methanol crude extracts were prepared and evaluated for their activity against Saccharomyces cerevisiae RS322N, R52Y and RS321 strains in the yeast mutant assay and their antioxidant capacity through the DPPH test. The dichloromethane extract from Myriocarpa stipitata (Urticaceae) showed moderate inhibitory activity against the three S. cerevisiae strains tested. The capacity of the dichloromethane extract from M. stipitata to inhibit the enzyme topoisomerase I and to cause DNA damage was inferred from these results. In the DPPH assay, the n-hexane crude extract from Costus sp. (Costaceae) showed good antioxidant activity (48%); in addition, the crude dichloromethane and aqueous-methanol extracts from Rhipsalis micrantha (Cactaceae) showed moderate antioxidant activity with percentage of 29 and 21%, respectively. Rev. Biol. Trop. 59 (3): 1089-1097. Epub 2011 September 01.

Desde tiempos inmemoriales, muchas plantas han sido usadas para el tratamiento de varias enfermedades e infecciones, este potencial ha sido explotado por la industria farmacéutica en la búsqueda de nuevos agentes analgésicos, anticancerígenos y antimicrobianos, entre otros. Consientes con esto, se evaluó la actividad de 35 extractos de 13 especies de plantas recolectadas en el Parque Regional Natural La Marcada (PRNLM, Colombia) contra las cepas mutadas de Saccharomyces cerevisiae RS322N, R52Y y RS321 en el ensayo de la levadura mutada y la capacidad antioxidante de los extractos a través del método del DPPH. El extracto crudo de diclorometano de Myriocarpa stipitata (Urticaceae) presentó actividad moderada contra las tres cepas de S. cerevisiae evaluadas. Lo cual permitió inferir la capacidad del extracto de diclorometano de esta especie para inhibir la enzima topoisomerasa I y causar daño al ADN. Además, en el ensayo del DPPH, el extracto de n-hexano crudo de Costus sp (Costaceae) mostró actividad antioxidante buena (48%), mientras que los extractos de diclorometano y acuoso metanólico crudos de Rhipsalis micrantha (Cactaceae) tuvieron actividad antioxidante moderada, con valores del 29 y 21%, respectivamente.

Expression and clinical significance of Topo Ⅱα , COX-2 in breast cancer tissues / 肿瘤研究与临床

Objective To explore the expression of Topo Ⅱα and COX-2 in breast cancer tissues and investigate their correlations to clinicopathologic feature of breast cancer. MethodsThe expression of Topo Ⅱα and COX-2 in 50 specimens of breast cancer and their normal tissues were detected by immunohistochemistry. Their correlation to clinicopathologic features of breast cancer were analyzed.ResultsThe positive rates of Topo Ⅱα were 64 % (32/50) and 22 % (11/50) and COX-2 were 68 % (34/50) , 14 %(7/50) in breast cancer and normal tissue (P＜0.05). The expression of Topo Ⅱα was correlated to degree of differentiation (P ＜0.05), not correlated to patient age, tumor size, clinical stage and lymph node metastasis(P ＞0.05). The expression of COX-2 was correlated to tumor size, degree of differentiation, clinical stage and lymph node metastasis (P ＜0.05), not correlated to patient age (P ＞0.05). Conclusion Topo Ⅱα and COX-2 expression can be used as an indicator for predicting the differentiation, infiltration and metastasis characteristics of breast cancer.

Anti-hepatoma activity of nitidine chloride and its effect on topoisomerase / 中国药理学通报

Aim To investigate the anti-tumor effect of nitidine chloride(NC)on human HepG2 hepatocellular transplanted tumor in nude mice and its effect on topoisomerase.Methods The subcutaneous transplantable tumor model of human liver cancer in nude mice was established and the anti-tumor effect of NC was calculated.The effects of NC on TopoⅠ/Ⅱ mediated-pBR322 DNA relaxation were measured by using agarose gel electrophoresis.Results NC inhibited significantly the growth of hepatoma,The inhibitory rate at the dose of 2.5,5,10 mg·kg~(-1) was 12.06%,35.63% and 60.91% respectively.At the concentration of 6.25 μmol·L~(-1),NC completely inhibited the pBR322 DNA cleavage mediated by TopoⅠ;at the concentration of 25 μmol·L~(-1),NC completely inhibited the pBR322 DNA cleavage mediated by Topo Ⅱ.Conclusion Nitidine Chloride can inhibit hepatic carcinoma growth in nude mice,The anti-tumor mechanism is probably related to the inhibitory effect on Topo.

The anti-tumor new drug:9-nitrocamptothecin / 国际外科学杂志

9-Nitrocamptothcin(9-NC)is an orally available new type camptothecinanalog with antineoplastic activity that results from inhibition of DNA topoisomerase Ⅰ.In the study we reviewed the feature of the drug,mechanism of action,update studies of preclinical and pancreas cancer clinical trial.

La ADN topoisomerasa tipo I de protozoos patógenos como Diana terapéutica de fármacos antitumorales / Type I DNA topoisomerase from protozoan pathogens as a potential target for anti-tumoral drugs

La utilización intensiva de fármacos antiparasitarios es la causa principal de la aparición de microorganismos parásitos multirresistentes en las regiones del planeta donde son precisamente endémicos. Los agentes etiológicos de las denominadas enfermedades tropicales -malaria, criptosporiodiosis, enfermedad del sueño, enfermedad de Chagas o los distintos tipos de leishmaniosis- son protozoos unicelulares sobre los que no se ha desarrollado en la actualidad ninguna vacuna eficaz y cuyo tratamiento se basa en medidas sanitarias preventivas y en el uso de medicamentos. La quimioterapia antiparasitaria actual es cara, no está ausente de efectos adversos y no supone beneficios a las empresas que la comercializan, por lo que la inversión en I & D es marginal comparada con la llevada a cabo para otros procesos patológicos de menor relevancia médica. La identificación de las ADN topoisomerasas como dianas farmacológicas se basa en los excelentes resultados obtenidos en los ensayos clínicos llevados a cabo con los derivados de la camptotecina en la terapia antitumoral. Las importantes diferencias estructurales entre las ADN topoisomerasas de tipo I de tripanosomas y leishmanias con respecto a sus homólogas de mamífero ha abierto un nuevo campo de investigación que combina las técnicas de biología molecular con la cristalización de proteínas para poder diseñar nuevos fármacos dirigidos específicamente a su inhibición. Revisamos aquí las características de estas nuevas dianas farmacológicas, así como los compuestos que en el momento están siendo utilizados para su inhibición en los agentes parasitarios que causan las principales enfermedades tropicales.

The intensive use of antiparasitic drugs is the main cause of the emergence of multiresistant parasite strains on those regions where these parasites are endemic. The aetiological agents of the so-called tropical diseases viz. malaria, cryptosporidiosis, sleeping sickness, Chagas disease or leishmaniasis, among others, are unicellular protozoan parasites with no immune-prophylactic treatment and where the chemotherapeutical treatment is still under controversy. At present, the chemotherapeutic approach to these diseases is expensive, has side or toxic effects and it does not provide economic profits to the Pharmaceuticals which then have no or scarce enthusiasm in R & D investments in this field. The identification of type I DNAtopoisomerases as promising drug targets is based on the excellent results obtained with camptothecin derivatives in anticancer therapy. The recent finding of significant structural differences between human type I DNAtopoisomerase and their counterparts in trypanosomatids has open a new field in drug discovery, the aim is to find structural insights to be targeted by new drugs. This review is an update of DNA-topoisomerases as potential chemotherapeutic targets against the most important protozoan agents of medical interest.

Cytotoxic and DNA-topoisomerase effects of lapachol amine derivatives and interactions with DNA

The cytotoxic activity of amino (3a-e), aza-1-antraquinone (4a-e) lapachol derivatives against Ehrlich carcinoma and human K562 leukemia cells was investigated. Cell viability was determined using MTT assay, after 48 (Ehrlich) or 96 h (K562) of culture, and vincristine (for K562 leukemia) and quercetin (for Ehrlich carcinoma) were used as positive controls. The results showed dose-dependent growth-inhibiting activities and that the amino derivatives were active against the assayed cells, whereas the 4a-e derivatives were not. The allylamine derivative 3a was the most active against Ehrlich carcinoma, with IC50 = 16.94 ± 1.25 muM, and against K562 leukemia, with IC50 = 14.11 ± 1.39 muM. The analogous lawsone derivative, 5a, was also active against Ehrlich carcinoma (IC50 = 23.89 ± 2.3 muM), although the 5d and 5e derivatives showed lower activity. The interaction between 3a-d and calf thymus DNA was investigated by fluorimetric titration and the results showed a hyperchromic effect indicating binding to DNA as presented of ethidium bromide, used as positive control. The inhibitory action on DNA-topoisomerase II-a was also evaluated by a relaxation assay of supercoiled DNA plasmid, and the etoposide (200 muM) was used as positive control. Significant inhibitory activities were observed for 3a-d at 200 muM and a partial inhibitory action was observed for lapachol and methoxylapachol.

p53, Heat Shock Protein 70 and Topoisomerase II Expression in Gallbladder Carcinoma

BACKGROUND: The present study was designed to investigate the expression of p53, Heat Shock Protein 70 (HSP70), and Topoisomerase (Topo) II alpha in the preneoplastic lesions and carcinomas of the gallbladder (GB) and to assess the correlation between the expression of these proteins and the clinicopathologic parameters by performing immunohistochemistry. METHODS: The immunohistochemical expressions of p53, HSP70 and Topo II alpha were evaluated in 38 gallbladder carcinomas and 3 adenomas. Fifteen CIS(s) and 8 dysplasias that were located adjacent to invasive carcinomas were also studied. RESULTS: A p53 expression was identified in 22 (57.9%) of the 38 GB carcinomas, in 9 (64.3%) of 14 CISs, and in none of the 8 dysplasias and 3 adenomas. A HSP70 expression was found in 11 (29%) of the 38 carcinomas, in 11 (78.6%) of 14 CIS(s), and in 4 (57.2%) of 7 dysplasias. A Topo II alpha expression was present in 36 (94.7%) of the 38 carcinomas, in 13 (92.9%) of 14 CIS(s), in 7 (100%) of 7 dysplasias and in 3 (100%) of 3 adenomas. p53 overexpression was related to the T stage of the primary tumor, while HSP70 and Topo II alpha were not related to any of the clinicopathologic parameters. CONCLUSION: p53 may be involved in GB carcinogenesis and in the progression of cancer. p53 may be also helpful for making the differential diagnosis between dysplasia and CIS. A further large study is needed to better elucidate the roles of HSP70 and Topo II alpha in GB carcinogenesis.

Pneumothorax as the First Clinical Manifestation of Systemic Sclerosis : A Case Report of Multiple Cystic Lung Lesions in Systemic Sclerosis / 결핵

No abstract available.

Expression of DNA Topoisomerase II-alpha as a Proliferating Marker in Urothelial Carcinoma of Urinary Bladder based on World Health Organization/International Society of Urological Pathology Consensus Classification: A Correlation with Expression of Ki-67

BACKGROUND: DNA topoisomerase II-alpha is linked with active cell proliferation in mammalian cells. The aim of this study was to examine the relationship between the expression of DNA topoisomerase II-alpha as a proliferating marker, and the expression of Ki-67 and apoptosis in urothelial carcinoma of urinary bladder based on World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification. METHODS: 73 urothelial carcinomas of the urinary bladder after transurethral resection and 25 carcinomas after radical cystectomy were investigated for histologic grading based on WHO and WHO/ISUP consensus classification. Formalin fixed, paraffin embedded tissue of 98 specimens from 73 patients were immunohistochemically stained for DNA topoisomerase II-alpha and Ki-67, and in situ TdT-mediated dUTP-biotin nick end labeling method for evaluation of apoptotic cells was performed. For each case, a DNA topoisomerase II-alpha, Ki-67, and apoptotic indices were determined. RESULTS: The histologic grades of 73 cases based on the WHO grading system were 21.9% (16 cases) in grade 1, 65.8% (48 cases) in grade 2, and 12.3% (9 cases). 5.5% (4 cases) of papillary neoplasm of low malignant potential, 47.9% (35 cases) of urothelial carcinoma of low grade, and 46.6% (34 cases) in urothelial carcinoma of high grade were reclassified using the WHO/ISUP consensus classification. Histologic grades based on two grading systems were correlated to invasion and stage (p<0.05). DNA topoisomerase II-alpha, Ki-67, and apoptotic indices were correlated to histologic grades based on two grading system and invasion. Also, the correlation of DNA topoisomerase II-alpha and Ki-67 indices, and DNA topoisomerase II-alpha and apoptotic indices were significant, respectively. CONCLUSIONS: DNA topoisomerase II-alpha appears to be an useful marker for assessing the proliferation potential of urothelial carcinoma of in the urinary bladder.

Expression of TopoⅡ gene in human bladder cancer multidrug-resistant cells / 中国癌症杂志

Purpose:To study the expression of TopoⅡ gene in multidrug resistant cells of human bladder cancer. Methods:The degree of drug resistance was detected by MTT method ;the expression of TopoⅡ gene in cell lines BIU 87/ADM and BIU 87 was detected with reverse transcriptase polymerase chain reaction. Results:The cell lines BIU 87/ADM were 56.4 times more resistant to ADM than the cell lines BIU 87;the expression of TopoⅡ gene was poorly positive in BIU 87/ADM but strongly positive in BIU 87 cells. Conclusions: The decreased expression of TopoⅡ gene in BIU 87/ADM cells might contribute to the development of multidrug resistance of human bladder cancer.

Mutations in the gyrA and parC genes of quinolone-resistant Shigella flexneri clinical isolates / 中华传染病杂志

Objective To identify the mutations of DNA gyrase gyrA and Topoisomerase Ⅳ parC genes in quinolone-resistant Shigella flexneri clinical isolates and evaluate the relevance of amino acid changes in GyrA and ParC to quinolone resistance. Methods Based on the antimicrobial susceptibility testing, 47 S.flexneri clinical isolates with different quinolone susceptibility were selected and the fragments including the quinolone resistance-determining region (QRDR) in gyrA and parC were PCR amplified and sequenced. SAS (V 8.2) software was used to analyze the correlation between quinolone resistance and changes in GyrA and ParC. Results Sense mutation(s) in gyrA and parC were commonly observed in all of 44 quinolone-resistant isolates, whereas no sense mutation was found in the 3 quinolone-susceptible ones. The most frequent mutation is at codon 83(TCG→TTG) of gyrA, which was observed in 43 quinolone-resistant isolates. The mixed model analysis indicated that the alterations in amino acid 83 of GyrA and amino acid 80 of ParC are close related to nalidixic acid resistance (P

Role of ATF on Transcriptional Regulation of DNA Topoisomerase II a Gene in HL - 60 Arrested to G2 / M and M Phase / 대한암학회지

PURPOSE: To gain insight on transcriptional repression of Topo II a in HL-60 cells arrested to G2/M and M phase, the levels of Topo IIa mRNA and the binding activity of ATF have been investigated with Northern blot hybridization and DNA mobility shift assay, respectively. MATERIALS AND METHODS: HL-60 cells were grown in RPMI 1640 medium supplemented with 10% heat-mactivated fetal bovine serum and antibiotics in a humidified 5% CO2 at 37C degree. Total RNA was prepared by a modification of the method of Karlinsey et al. Northern blot hybridization was performed by the method of Virca et al. A Xho I-Mlu I fragment of phTOP2 was used as probe for Northern blot analysis of Topo II a mRNA. DNA mobility shift assay was performed by the method of Lim et al. End labeled DNA oligomer (upper strand, 5-TCTCCGCTATGACGCCGAGTGGTG-3) for ATF binding activity was mixed with nuclear extracts in a 20 pl reaction volume containing 60 mM KC1, 12 mM HEPES, pH 7.9, 5 mM MgCl2, 0.2 mM EDTA, 0.2 mM DTT, 12% glycerol, and 2 ug of poly [dI-dC]. RESULTS: HL-60 cells were arrested at G2/M phase and M phase after taxol or nocodazole treatment. The levels of Topo II a mRNA were reduced at 24 hours after exposure with nocodazole or taxol but the unknotting activities were not changed. DNA mobility shift assay using oligonucleotide containing the ATF binding site showed that ATF binding activity was reduced after pretreatment of nododazole or taxol. CONCLUSIONS: These results suggest that the reduction of ATF binding activity may be important to transcriptional repression of Topo II a gene by nocodazole and taxol in HL- 60 cells.