The Activity of Erianin and Chrysotoxine from Dendrobium chrysotoxum to Reverse Multidrug Resistance in B16/h MDR-1 Cells

The ability of two dihydrostilbene derivatives erianin and chrysotoxine from Dendrobium chrysotoxum to reverse multidrug resistant (MDR) cells was investigated using murine B16 melanoma cells transfected with the human MDR 1 gene and crossresistant to vinblastine and adriamycin (B16/h MDR 1 cells). Both of the two compounds were shown to increase the accumulation of adriamycin, the P glycoprotein (P gp) substrate, in B16/h MDR 1 transfectants.

Reversal of Adriamycin Resistance in Human Mammary Cancer Cells by Small Interfering RNA of MDR1 and MDR3 Genes

The purpose of this paper is to investigate the reversal effect of small interfering RNA （siRNA） targeting MDRI and MDR3 genes on the resistance of MCF-7/ADR cells to adriamycin. siRNA plasmid vector targeting MDRI and MDR3 genes was transfected into MCF-7/ADR cells, and then was stained with Annexin-V FITC （fluorescein isothiocyanate conjugated） to detect the early stage cell apoptosis by flow cytometry （FCM）. 50 % inhibition concentration （IC50） of adriamycin for MCF-7/ADR cells was determined by MTT method. MDRI and MDR3 mRNA was assessed by RT-PCR. Treatment of MCF-7/ADR cells with the two kinds of siRNAs resulted in a reversal of adriamycin resistance of MDR to different extents. 1） The apoptosis efficiency of MDRI and MDR3 siRNA vector after transfection was （18.21 ± 1.65） % and （9.07±2.16） % respectively （P〈0.05）, and there was significant differences in the apoptosis efficiency between pSuppressor Neo vector and the MDRIsiRNA or MDR3 siRNA vector （P〈0.01）; 2） The reversal effect of MDRIsiRNAis higher than that of MDR3 siRNA （P〈0.05）; 3 ） The expression of MDRI and MDR3 mRNA can be restrained by pSuppressor Neo MDRI and MDR3 siRNA respectively, and the reduction in the mRNA level was in a time-dependent manner （P〈0.01）. MDRI and MDR3 gene silencing can enhance intracellular adriamycin accumulation in MCF-7/ADR cells, improve sensitivity of MCF-7/ADR cells to adriamycin, and induce cell apoptosis. The reversal effect of adriamycin resistance by siRNA of MDR1 was more effective than that of MDR3.

Reversing multidrug resistance by RNA interference through the suppression of MDR1 gene in human hepatoma cells

AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.

EXPRESSION OF mdr-1 GENE IN CANCER TISSUE AND ITS ASSOCIATION WITH MORPHOLOGICAL INDEXES OF ESOPHAGEAL CARCINOMA IN ANYANG

Objective: Overexpression of mdr-1 gene is associated with multidrug resistance (MDR) and aggressive characteristics of malignance. Our purposewas to detect the levels of P-gp expression in fresh untreated esophageal carcinomas, and to correlate these levels to current prognostic indicators of morphology.Methods: Reverse transcription polymerase chain reaction (RT-PCR) was used to investigate mdr-1 gene expression of 46 samples from untreated esophageal carcinoma, and compared the positive incidences among differentiated grades, TNM stages and macroscopic types.Results: All 46 samples were pathologically squamous cell carcinoma. The positive' incidences of mdr-1 gene expression were 37% (17/46) in whole group,35% (6/17), 40% (8/20), 33% (3/9), for Ⅰ,Ⅱ and Ⅲdifferentiated grades, respectively. The expression rates of 33% (6/18), 40% (5/12), and 37% (6/16), were found in Ⅱa, Ⅱ, and Ⅲ stage of TNM, respectively. In macroscopic type view, the positive incidence was 37%(3/8) in constrictive, 33% (5/15) in fungating, 40% (6/14)in marrowlike, 33% (319) in ulcerative type. There were no statistically significant differences among each category system of morphology.Conclusion: The result, high level expression of mdr-1 gene in untreated esophageal carcinoma, suggested the poor efficacy of chemotherapy for some esophageal carcinoma patients. And we should cautiously choose cases who will receive chemotherapy. Surgery is still the best treatment for carcinoma of esophagus. Besides, the data also revealed that the expression of mdr-1 gene in untreated esophageal cancer was independent of morphologic prognostic indexes, and that there were no correlation between mdr-1 gene expression and morphological indexes.

REVERSAL EFFECTS OF MIFEPRISTONE ON MULTIDRUG RESISTANCE(MDR) IN DRUG-RESISTANT BREAST CANCER CELL LINE MCF7/ADR IN VITRO AND IN VIVO

To explore the reversal effect of mifepristone on multidrug resistance (MDR) in drug-resistant human breast cancer cell line MCF7/ADR and its mechanisms. Methods: Expression of MDR1 and MDR-associated protein(MRP) mRNA in MCF7/ADR cells was detected using reverse transcription- polymerase chain reaction(RT-PCR). Western blotting was used to assay the protein levels of P-glycoprotein (P-gp) and MRP. Intracellular rhodamine 123 retention and [3H]vincristine (VCR) accumulation were measured by flow cytometry and liquid scintillation counter, respectively. MTT reduction assay was used to determine the sensitivity of cells to the anticancer agent, adriamycin (ADR). Additionally, a MCF7/ADR cell xenograft model was established to assess the reversal effect of mifeprisone on MDR in MCF7/ADR cells in vivo. Results: Miferpristone dose-dependently down- regulated the expression of MDR1 and MRP mRNA in MCF7/ADR cells, accompanied by a significant decrease in the protein levels of P-gp and MRP. After exposure to 5, 10, and 20 mmol/L mifepristone, MCF7/ADR cells showed a 3.87-, 5.81-, and 7.40-fold increase in the accumulation of intracellular VCR(a known substrate of MRP), and a 2.14-, 4.39-, and 5.53-fold increase in the retention of intracellular rhodamine 123(an indicator of P-gp function), respectively. MTT analysis showed that the sensitivity of MCF7/ADR cells to ADR was enhanced by 7.23-, 13.62-, and 20.96-fold after incubation with mifepristone as above-mentioned doses for 96 h. In vivo, mifepristone effectively restored the chemosensitivity of MCF7/ADR cells to ADR. After 8 weeks of administration with ADR(2 mg穔g-1穌-1) alone or in combination with mifepristone(50 mg穔g-1穌-1), the growth inhibitory rate of xenografted tumors in nude mice was 8.08% and 37.25%, respectively. Conclusion: Mifepristone exerts potent reversal effects on MDR in MCF7/ADR cells in vitro and in vivo through down- regulation of MDR1/P-gp and MRP expression and inhibition of P-gp- and MRP-dependent drug efflux, thus increasing the sensitivity to anticancer drug.

基于MDR模型的喹诺酮类抗生素对蛋白核小球藻联合毒性作用评估

为考察新污染物中喹诺酮类抗生素混合物的联合毒性效应,以常见的氧氟沙星(Ofloxacin,OFXL)、环丙沙星(Ciprofloxacin,CIP)、诺氟沙星(Norfloxacin,NFXL)3种喹诺酮类抗生素为供试品,通过96 h急性毒性试验测定3种抗生素对蛋白核小球藻(Chlorella pyrenoidosa)生长抑制的单一毒性及二元和三元混合体系(共计20组)的联合毒性,通过等效线图法、浓度加和模型(CA)、独立作用模型(IA)、模型偏移率(MDR)和组合指数法评价二元和三元混合体系抗生素的相互作用类型。结果表明:①3种喹诺酮类抗生素对蛋白核小球藻在96 h均呈现明显的生长抑制,以半数效应浓度EC_(50)的负对数(pEC_(50))作为判断毒性大小的指标,毒性呈NFXL(pEC_(50)=-2.02)>CIP(pEC_(50)=-2.12)>OFXL(pEC_(50)=-2.23)的特征。②混合体系毒性相互作用类型以协同作用为主,毒性相互作用类型与混合体系组分浓度比、毒性效应区域和污染物浓度范围有关。混合体系中混合物组分浓度比最接近1∶1时,协同作用最强,毒性最大。③混合体系在低浓度范围(0%~30%)时,毒性相互作用类型以加和作用为主;在中高浓度范围(30%~100%)时,毒性相互作用随混合体系的不同而呈现出不同类型。研究显示,环境水体中喹诺酮类抗生素对蛋白核小球藻有一定的毒性效应,且抗生素二元、三元混合体系的协同毒性效应呈毒性增大的趋势。

Quantitative detection of peripheral MDR genes in breast cancer before chemotherapy and their clinical significances

Objective： To explore expressions of multidrug resistance gene （MDR） product P170 and peripheral blood MDR1 mRNA in breast cancer tissue and their clinical significances. Methods： Fluorescent quantitative RT-PCR and immunohistochemistry were used to detect peripheral blood MDR1 mRNA before chemotherapy in breast cancer tissue samples from 32 cases with P170 positive （trial group） and 11 cases with P170 negative （control group）. Results： There were 14 cases （43.75%） peripheral blood MDR1 mRNA positive and 18 cases （56.25%） negative in 32 cases P170 positive breast cancer patients, while there were 6 cases （54.55%） peripheral blood MDR1 mRNA positive and 5 cases （45.45%） negative in 11 cases P170 negative breast cancer patients; there wasn＇t a significance difference with peripheral blood MDR1 mRNA express rate in P170 positive （43.75%） group and P170 negative （54.55%） group （x2 = 0.383, P 〉 0.05）. There were 12 cases （37.50%） Her-2 positive and 20 cases （62.50%） negative in P170 positive group; there were 2 cases （18.18%） Her-2 positive and 9 cases （81.82%） negative in P170 negative group; there wasn＇t a significance difference with Her-2 positive rate in P170 positive group （37.50%） and P170 negative （18.18%） group （χ^2= 1.391, P 〉 0.05）. There were 13 cases （40.63%） ER positive and 19 cases （59.37%） negative in P170 positive group; there were 7 cases （63.64%） ER positive and 4 cases （36.36%） negative in P170 negative group; there wasn＇t a significance difference with ER positive rate in P170 positive group （40.63%） and P170 negative （63.64） group （χ^2 = 1.742, P 〉 0.05）. There were 20 cases （62.50%） PR positive and 12 cases （37.50%） negative in P170 positive group; there were 4 cases （36.36%） PR positive and 7 cases （63.64%） negative in P170 negative group; there wasn＇t a significance difference with PR positive rate in P170 positive group （62.50%） and P170 negative （36.36%） group （χ^2 = 2.267, P 〉 0.05）. There were 9 cases （28.12%） with lymphaden metastasis and 23 cases （71.88%） without lymphaden metastasis in P170 positive group; there were 5 cases （45.45%） with lymphaden metastasis and 6 cases （54.55%） without lymphaden metastasis in P170 negative group; there wasn＇t a significance difference with lymphaden metastasis rate in P170 positive group （28.12%） and P170 negative （45.45%） group （χ^2 = 1.120, P 〉 0.05）. Conclusion： 1） There were possibly MDR expressing infrequently in carcinoma tissue and peripheral blood before chemotherapy. 2） FQ-RT-PCR for detecting of peripheral blood MDR1 mRNA is special, sensitive and reliable. It can be used as new molecular biology diagnostic maker dynamic detecting peripheral blood MDR1 mRNA for regulating chemotherapy proposal and elevating chemotherapy effect.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells

In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparti- cles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDRl-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope （TEM）. MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration （IC50） ofpaclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control （P〈0.05）. MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC_50 （0.197±0.003, 0.144±0.001, 0.120±0.004） were decreased with difference being significant when compared with that in A2780/TS （0.269±0.003） cells control （P〈0.05）. It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

Prognostic significance of MDR-1 P-glycoprotein expression in breast cancer

Objective： To investigate the expression of MDR-1 P-glycoprotein（MDR-1 Pgp） in breast cancer and analyze its correlation to the biological behavior and prognosis of the disease. Methods：The expression of MDR-1 Pgp was examined in 75 cases of breast cancer patients by using three different monoclonal antibodies（JSB1, C219 and C494） with S-P immunohistochemisty. These patients were followed up for 5 years, and the correlation between MDR-1 Pgp expression, survival rate and lymph metastasis was analyzed. Results： Positive detection of MDR-1 Pgp by JSB1, C219 and C494 in 75 cases of breast cancer was 86.7%, 48% and 85.3%, respectively. MDR-1 Pgp expression was not related to ages of patients （P 〉 0.05）. JSBl-detected expression of MDR-1 Pgp was related to lymph node metastasis（P〈 0.05）; while C219 and C494 were not（P 〉 0.05）. The patients with MDR-1 Pgp expression positively detected by either two of the three antibodies, had five-year survival rate that was significantly higher than those positively detected by all the three antibodies（P 〈 0.05）. Conclusion：Three antibodies should be used simultaneously to detect MDR-1 Pgp expression in breast cancer. Positive MDR-1 Pgp expression in breast cancer detected by all the three antibodies may represent a poor prognosis; while positive MDR-1 Pgp detection by JSB1 and C494 is associated with lymph metastasis.

CONGENITAL EXPRESSION OF mdr-1 GENE IN FRESH CANCER TISSUES FROM SEVERAL HIGH-INCIDENCE NEOPLASMS WITHOUT PREOPERATIVE CHEMOTHERAPY

Objective: The purpose of the present study is to detect characteristics of primary expression of mdr 1 gene in several neoplasms which has high morbidity in clinic. Methods: 151 resected samples, which are pathologically malignant and clinically untreated before operation, were obtained from Anyang Cancer Hospital. All of them were investigated with RT PCR for the expression of mdr 1 gene and correlated each other. Besides, we evaluated the advantages of RT PCR in this study. Results: The mdr 1 gene expression rate of these 151 samples, including cancers of stomach and gastric cardia (n=51), esophagus (n=46), colorectum (n=16), breast (n=15), thyroid (n=10), lung (n=9), uterine cervix (n=4), was 33.3%, 37%, 31.3%, 13.2%, 40%, 55%, 0%, respectively. Conclusion: Compared with other methods, RT PCR for studying mdr 1 gene expression had certain advantages in simplicity, reliability, and accuracy. Overexpression of mdr 1 gene in these neoplasms suggested that cases should be distinguished before treatment according to MDR of tumor and to choose effective drugs for individual cancer patient.

Smear-Negative Multidrug-Resistant Tuberculosis a Significance Hidden Problem for MDR-TB Control: An Analysis of Real World Data

Purpose: The drug resistance pattern in tuberculosis (TB) is still under investigated. We analyzed the clinical data from the patients with smear positive TB and applied the model to predict the patients with smear-positive TB. Materials and Methods: Medical records information of 6977 cases was included from 11,950 inpatients from January 2009 to November 2013. The cases data were divided into a training set, test set and prediction set. Logistic regression analysis was applied to the training set data to establish a prediction classification model, the effect of which was then evaluated using the test set by receiver operating characteristic (ROC) analysis. The model was then applied to the prediction set to identify incidence of snMDR-TB. Results: Sixteen factors which correlate with MDR-TB-including frequency of hospitalization, province of origin, anti-TB drugs, and complications, were identified from the comparison between SP-TB and spMDR-TB. The area under the ROC curve (AUC) of the prediction model was 0.752 (sensitivity = 61.3%, specificity = 83.3%). The percentage of all inpatients with snMDR-TB (snMDR-TB/Total) was 28.7% ± 0.02%, while that of all SN-PTB with snMDR-TB (snMDR-TB/SN-PTB) was 26.5% ± 0.03%. The ratio of snMDR-TB to MDR-TB (snMDR-TB/MDR-TB) was 2.09 ± 0.33. Conclusion: snMDR-TB as an important source of MDR-TB is a significant hidden problem for MDR-TB control and can be identified by the prediction model. A kind of vicious circle with a certain delay effect exists between snMDR-TB and MDR-TB. To better control MDR-TB, it is necessary to pay greater attention to snMDR-TB, conduct further research and develop targeted therapeutic strategies.

Mechanisms Efflux Pumps of <i>Acinetobacter baumannii</i>(MDR): Increasing Resistance to Antibiotics

Acinetobacter baumannii has greatly increased its degree of resistance to become multidrug resistant (MDR) over the past 30 years and is on the red line of the most widely replicated bacteria according to World Health Organization (WHO). The efflux pumps are the main cause for the increasing antibiotic resistance of A. baumannii originated from nosocomial infection. The progressive resistance of A. baumannii even on the recent drugs (tigecycline and fosfomycin) reduces to very effective antibiotic scale. With attention focused on MDR and pan-drug-resistant (PDR) in A. baumannii multiple works on efflux pumps chemical inhibitor (NMP, PAβN, omeprazole, verapamil, reserpine, CCCP) are still in progress. Certain inhibitors from plants (Biricodar and timcodar, Falvone, Mahonia, Dalea versicolor, Lycopus europaeus, and Rosmarinus officinalis) have the capability to have such compounds according to their very significant synergistic effect with antibiotics. In this review we focused on the growth of antibiotic resistance to explain the mechanism of efflux pumps into these different super families and a comprehensive understanding of the extrusion, regulation and physiology role of drug efflux pumps in the essential development of anti-resistivity drugs. We recapitulated the evolution of the work carried out in these fields during the last years and in the course of elaboration, with the aim of increasing the chances of decreasing bacterial resistivity to antibiotics.

pH-sensitive micelles self-assembled from star-shaped TPGS copolymers with ortho ester linkages for enhanced MDR reversal and chemotherapy

TPGS approved by FDA can be used as a P-gp inhibitor to effectively reverse multi-drug resistance(MDR)and as an anticancer agent for synergistic antitumor effects.However,the comparatively high critical micelle concentration(CMC),low drug loading(DL)and poor tumor target limit its further clinical application.To overcome these drawbacks,the pH-sensitive star-shaped TPGS copolymers were successfully constructed via using pentaerythritol as the initial materials,ortho esters as the pH-triggered linkages and TPGS active-ester as the terminated MDR material.The amphiphilic star-shaped TPGS copolymers could self-assemble into free and doxorubicin(DOX)-loaded micelles at neutral aqueous solutions.The micelles exhibited the lower CMC(8.2×10^(−5) mg/ml),higher DL(10.8%)and long-term storage and circulation stability,and showed enhanced cellular uptake,apoptosis,cytotoxicity,and growth inhibition for in vitro MCF-7/ADR and/or MCF-7/ADR multicellular spheroids and in vivo MCF-7/ADR tumors via efficiently targeted drug release at tumoral intracellular pH(5.0),MDR reversal of TPGS,and synergistic effect of DOX and TPGS.Therefore,the pH-sensitive micelles self-assembled from star-shaped TPGS copolymers with ortho ester linkages are potentially useful to clinically transform for enhanced MDR cancer treatment.

Small Interfering RNA Targeting MDR1 Inhibits Ovarian Cancer Growth and Increases Efficacy of Chemotherapy in vivo

Objective： To further validate a knockdown approach for circumventing the multidrug resistance gene （MDR1）, we used small interfering RNA（siRNA） targeting MDR1 gene to inhibit the expression of MDR1 gene and P-glycoprotein（P-gp） in vivo. Methods： Ascite tumor xenografts were established by implanting human ovarian carcinoma cells SKOV3/AR intraperitoneally into the nude mice. The mice were randomized into the following three treatment groups with each group six mice respectively： Taxol, Taxol with lipofectamine and Taxol with siRNA/MDR1- lipofectamine intraperitoneal injection. The tumor growth rate and the ascite growth rate of mice were investigated. The expressions of MDR1 gene and P-gp in mice were determined by reverse transcription-polymerase chain reaction（RT-PCR） and immunohistochemistry respctively. Results： The growth of tumors and ascites in mice treated with Taxol and siRNA/MDR1- lipofectamine was significantly inhibited compared with those in mice of other groups. After 28 days＇ treatment, the average tumor weight and ascite volume decreased by 43.6% and 29.7% in the group treated with Taxol and siRNA/MDRl-lipofectamine compared with these treated with Taxol alone （P〈0.001）. The expressions of MDR1 gene and P-gp in the group treated with Taxol and siRNA/MDRl-lipofectamine were also decreased compared with those in the group treated with Taxol alone （P〈0.001）. Conclusion： Small interfering RNA targeting-MDR1 can effectively and specifically suppress the expression of MDRl（P-glycoprotein） and inhibit ovarian cancer growth in vivo.

EFFECTS OF NEOADJUVANT CHEMOTHERAPY ON MDR1 AND MRP GENE EXPRESSION IN PRIMARY BREAST CANCER

Objective: To investigate the effects of neoadjuvant chemotherapy on the expression of drug resistance genes, multidrug resistance-1 (MDR1) and multidrug resistance-associated protein (MRP), in patients with primary breast cancer. Methods: MDR1 and MRP expression were detected by semi-quantitative RT-PCR in 20 patients with primary breast cancer, before and after chemotherapy. Results: Before chemotherapy, MDR1 and MRP expression can be detected in 15 cases (75%) and 18 cases (90%) respectively. After chemotherapy, expression of MDR1 is not significantly different from that before chemotherapy, but expression of MRP is significantly different from that before chemotherapy. Conclusion: Expression of drug resistance gene MRP, but not MDR1, is enhanced in patients with primary breast cancer submitted to neoadjuvant chemotherapy.

Identification, Synthesis, Isolation and Spectral Characterization of Multidrug-Resistant Tuberculosis (MDR-TB) Related Substances

Several related substances were detected at trace level in (2R)-2,3-dihydro-2-methyl-6-nitro-2-[[4-[4-[4-(trifluoromethoxy)phenoxy]-1-piperidinyl] phenoxy] methyl]imidazo[2, 1-b]oxazole drug substance by a newly developed high-performance liquid chromatography method. All related substances were characterized rapidly but some impurities were found to be intermediates. Proposed structures were further confirmed by characterization using NMR, FT-IR, and HRMS techniques. Based on the spectroscopic data;unknown related sub-stances were characterized as 1-(Methylsulfonyl)-4-[4-(trifluoromethoxy) phenoxy]piperidine;4-{4-[4-(Tri-fluoromethoxy)-phenoxy]piperidin-1-yl}phenol and 4-{4-[4-(trifluoromethoxy)phenoxy]piperidin-1-yl}phenyl methane sulfonate;4-Bromophenyl methane sulfonate, Ethyl 3,6-dihydro-1(2H)-pyridine carboxylate, (2S)-3-(4-Bromophenoxy)-2-hydroxy-2-methylpropyl methane sulfonate, (2S)-3-(4-Bromophenoxy)-2-methylpropane-1,2-diyldimethane-sulfonate, (2S)-2-Methyl-3-(4-{4-[4-(trifluoromethoxy) phenoxy]-piperidin-1-yl} phenoxy)-propane-1,2-diyldimethane sulfonate, (S)-3-(4-Bromophenoxy)-2-methyl-propane-1,2-diol and corresponding Enantiomer, (2R)-2-[(4-Bromo-phenoxy)methyl]-2-methyloxirane and (2R)-2-[(4-bromophenoxy)methyl]-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazole. A possible mechanism for the formation of these related substances is also proposed.

MODULATION OF MDR-1 GENE IN HUMAN BREAST CANCER CELLS BY SODIUM BUTYRATE AND DMSO

Objective: To analyze the regulation effect of MDR-1 gene in human breast cancer cell by the differentiating agents, sodium butyrate and dimethyl sulfoxide. Methods: 1. A sensitive assay, RT-PCR, was used to measure the mRNA level before and after the treatment of sodium butyrate, DMSO, using β-actin as control; 2. Evaluated the effect of sodium butyrate, DMSO on MDR-1 gene expression of human breast cancer at the protein level by immunoflow cytometry; 3. P-glycoprotein function was examined after accumulation of the fluorescent drug, Phodamine-123, by flow cytometry; 4. Chemosensitivity to doxorubicin was analyzed using the MTT assay. Results: Sodium butyrate and DMSO were found to increase the MDR characteristics on MDR-1 gene, MDR-1 expression levels, P-glycoprotein function and chemosensitivity to doxorubicin. Conclusion: sodium butyrate, DMSO can modulate the MDR-1 gene at gene level, protein level, protein function level and cell level.

In Vitro Study of Ultrasound on Multidrug Resistance in MDR Human Hepatoma HepG_2 Cells

OBJECTIVE The aim of the study was to examine the reversal effects of ultrasound （US） on the MDR in HepG2/ADM, a HepG2 cell line resistant to Adriamycin （ADM）, and to study the mechanism of US action.METHODS Using the MTT assay, the effects of US on MDR in HepG2/ADR cells were studied. Before and after the treatment with 0.5 W/cm^2 low intensity ultrasound （LIUS）, the expression of the MDR-related genes, mdrl, mrp and lrp was assayed with the reverse transcriptase polymerase chain reaction （RT-PCR） and the levels of their respective protein expression determined by flow cytometry. By using confocal laser scanning microscopy （CLSM）, we examined the intracellular daunorubicin （DNR） distribution, and the effects on the cells of treatment with US or DNR.RESULTS LIUS significantly reversed MDR in HepG2/ADR cells. After treatment with LIUS at 0.5 W/cm^2, chemosensitivity to ADM and DNR increased 3.35-fold and 2.81-fold, respectively. The reversal activity by LIUS plus verapamil （VER） was stronger than with either US or VER alone. After treatment with 0.5 W/cm^2, the expression of both the MDR1 and the MRP mRNA genes began to decline （P 〈 0.01 and P 〈 0.05, respectively）; the expression of LRP showed no significant changes. Changes in the expression of the P-glycoprotein （P-gp） and MRP were similar to those of their mRNA expressions. Results of the CLSM showed that administration of US （0. 5 W/cm^2） or VER （15.7 uM） with DNR to HepGa/ADM cells showed a significant change in the distribution of DNR in the cells.CONCLUSION Our results show that LIUS can reverse MDR. The reversal effects are stronger than those of either US or VER alone, when combined with VER administration. As LIUS is noninvasive causing no toxicity, it might have potential for clinical application. The reversal mechanism needs further study.

Descriptive Epidemiology of Multidrug Resistance Tuberculosis (MDR-TB) in Bangladesh

Background: The number of reported MDR-TB cases has been increasing in recent years. Objectives: To describe the epidemiological profile of MDR-TB cases in Bangladesh. Design: This was a descriptive cross-sectional study. Settings: The study was conducted among the multi drug resistant tuberculosis patient admitted in the National Institute of Diseases of the Chest and Hospital (NIDCH) Dhaka, Bangladesh. Samples: 148 confirmed cases of MDR-TB. Materials and Methods: Hospital admitted MRD-TB cases were randomly chosen from the above mentioned hospital. Semi-structured and pretested questionnaire were introduced by researcher. Clinical and treatment data i.e. duration of TB drug intake, report of sputum, X-ray and blood test etc. were extracted from the hospital record. Results: Study found, majority of the participants (56.1%) were in the age group of 16 - 30 years. 64.2% of the study subjects were married. Majority of the participants education were whether under primary or primary level. 24.3% participant’s family member and 14.5% of neighbor were having TB. Most common comorbidity were diabetes, pulmonary infection, hearing loss, psychiatric symptoms, chest pain, joint pain etc. 63.5% respondent had high degree of AFB for sputum positivity and more than 98% had positive finding in X-ray chest. On an average ESR was low and also few cases of extremely low ESR were found. 71.6% were under twenty four months regimen. Conclusion: We can conclude that, many possible factors for MDR-TB. There is an urgent need for further study to confirm the exact factors in Bangladesh and address those immediately.

Influence of Prenatal Surveillance on Maternal and Perinatal Prognosis: A Prospective Study over 6 Months at the Maternity Ward of the Owendo University Hospital (Gabon)

Introduction: The occurrence of pregnancy in women is a risky situation. Prenatal care is necessary, which is not often the case in our context. Aim: To analyze the influence of antenatal surveillance on maternal and perinatal prognosis. Patients and Method: Preliminary longitudinal and analytical survey at the Owendo University Hospital (OHU) over 6 months. It focused on prenatal surveillance. The study population consisted of parturients who gave birth within 24 hours and we studied sociodemographic characteristics, variables related to antenatal contact, those of delivery as well as maternal and newborn outcomes. Results: 2485 deliveries were recorded and 1300 patients were retained according to the inclusion criteria. No prenatal contact (ANC0) was performed in 93 (7.15%), insufficient (ANCI) in 943 patients (72.5%), and sufficient (ANCS) in 264 patients (20.30%). Patients with low school level were significantly found when the NPC was not performed or insufficient and the same was true for the group of patients who were not employed and those who were single (p < 0.005). The caesarean section rate and perinatal mortality are high in this case. Conclusion: The quality of prenatal contact is insufficient in our context. The absence or inadequacy of the latter has a strong negative impact on maternal and perinatal morbidity and mortality.