Efficacy and Safety of Combined Bedaquiline and Delamanid Use among Patients with Multidrug-Resistant Tuberculosis in Beijing,China

Objectives The combined use of bedaquiline and delamanid(BDQ-DLM)is limited by an increased risk of prolonging the QTc interval.We retrospectively evaluated patients who received DLM/BDQcontaining regimens at a TB-specialized hospital.We aimed to present clinical efficacy and safety data for Chinese patients.Methods This case-control study included patients with multidrug-resistant tuberculosis(MDR-TB)treated with BDQ alone or BDQ plus DLM.Results A total of 96 patients were included in this analysis:64 in the BDQ group and 32 in the BDQ+DLM group.Among the 96 patients with positive sputum culture at the initiation of BDQ alone or BDQ combined with DLM,46 patients(71.9%)in the BDQ group and 29(90.6%)in the BDQ-DLM group achieved sputum culture conversion during treatment.The rate of sputum culture conversion did not differ between the two groups.The time to sputum culture conversion was significantly shorter in the BDQ-DLM group than in the BDQ group.The most frequent adverse event was QTc interval prolongation;however,the frequency of adverse events did not differ between the groups.Conclusion In conclusion,our results demonstrate that the combined use of BDQ and DLM is efficacious and tolerable in Chinese patients infected with MDR-TB.Patients in the BDQ-DLM group achieved sputum culture conversion sooner than those in the BDQ group.

Apatinib reduces liver cancer cell multidrug resistance by modulating NF-κB signaling pathway

Objectives:This investigation aimed to elucidate the inhibitory impact of apatinib on the multidrug resistance of liver cancer both in vivo and in vitro.Methods:To establish a Hep3B/5-Fu resistant cell line,5-Fu concentrations were gradually increased in the culture media.Hep3B/5-Fu cells drug resistance and its alleviation by apatinib were confirmed via flow cytometry and Cell Counting Kit 8(CCK8)test.Further,Nuclear factor kappa B(NF-κB)siRNA was transfected into Hep3B/5-Fu cells to assess alterations in the expression of multidrug resistance(MDR)-related genes and proteins.Nude mice were injected with Hep3B/5-Fu cells to establish subcutaneous xenograft tumors and then categorized into 8 treatment groups.The treatments included oxaliplatin,5-Fu,and apatinib.In the tumor tissues,the expression of MDRrelated genes was elucidated via qRT-PCR,immunohistochemistry,and Western blot analyses.Results:The apatinibtreated mice indicated slower tumor growth with smaller size compared to the control group.Both the in vivo and in vitro investigations revealed that the apatinib-treated groups had reduced expression of MDR genes GST-pi,LRP,MDR1,and p-p65.Conclusions:Apatinib effectively suppresses MDR in human hepatic cancer cells by modulating the expression of genes related to MDR,potentially by suppressing the NF-κB signaling pathway.

Diarrheal Diseases: A Review on Gastroenteritis Bacteria Global Burden and Alternative Control of Multidrug-Resistant Strains

Diarrheal diseases represent a significant and pervasive health challenge for humanity. The aetiology of diarrheal diseases is typically associated with the presence of enteropathogens, including viruses, bacteria and parasites. The implementation of preventive measures, including the maintenance of good food hygiene, effective water sanitation, and the development of rotavirus vaccines, has resulted in a notable reduction in the prevalence of the disease. However, the emergence of bacterial multidrug resistance due to the past or present inappropriate use of antibiotics has rendered bacterial infections a significant challenge. The objective of this review is threefold: firstly, to provide an overview of diarrheal diseases associated with bacteria;secondly, to offer a concise analysis of bacterial multidrug resistance on a global scale;and thirdly, to present the potential of filamentous fungi as an alternative solution to the challenge posed by multidrug-resistant strains. Campylobacter spp. is the most dangerous bacteria, followed by Shigella spp. and Vibrio cholerae in all age groups combined. However, Shigella spp. was the deadliest in children under five years of age and, together with E. coli, are the most antibiotic-resistant bacteria. With their highly developed secondary metabolism, fungi are a reservoir of natural bioactive compounds.

Identification of FDA-Approved Drugs as Modulators of Multidrug Resistance Protein 2 (MRP2/ABCC2) Expression Levels in MRP2-Overexpressing Cells: Preliminary Data

Multidrug Resistance Protein 2 (MRP2) is an ATP-dependent transmembrane protein that plays a pivotal role in the efflux of a wide variety of physiological substrates across the plasma membrane. Several studies have shown that MRP2 can significantly affect the absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles of many therapeutic drugs and chemicals found in the environment and diet. This transporter can also efflux newly developed anticancer agents that target specific signaling pathways and are major clinical markers associated with multidrug resistance (MDR) of several types of cancers. MDR remains a major limitation to the advancement of the combinatorial chemotherapy regimen in cancer treatment. In addition to anticancer agents, MRP2 reduces the efficacy of various drug classes such as antivirals, antimalarials, and antibiotics. The unique role of MRP2 and its contribution to MDR makes it essential to profile drug-transporter interactions for all new and promising drugs. Thus, this current research seeks to identify modulators of MRP2 protein expression levels using cell-based assays. A unique recently approved FDA library (372 drugs) was screened using a high-throughput In-Cell ELISA assay to determine the effect of these therapeutic agents on protein expression levels of MRP2. A total of 49 FDA drugs altered MRP2 protein expression levels by more than 50% representing 13.17% of the compounds screened. Among the identified hits, thirty-nine (39) drugs increased protein expression levels whereas 10 drugs lowered protein expression levels of MRP2 after drug treatment. Our findings from this initial drug screening showed that modulators of MRP2 peregrinate multiple drug families and signify the importance of profiling drug interactions with this transporter. Data from this study provides essential information to improve combinatorial drug therapy and precision medicine as well as reduce the drug toxicity of various cancer chemotherapies.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Multidrug dissolvable microneedle patch for the treatment of recurrent oral ulcer

Recurrent oral ulcer is a painful oral mucosal disorder that affects 20%of the world’s population.The lack of a radical cure due to its unknown underlying cause calls for innovative symptomatic treatments.This work reports a hyaluronic acid-based dissolvablemicroneedle patch(ROUMNpatch,short for recurrent oral ulcer microneedle)loaded with dexamethasone acetate,vitamin C and tetracaine hydrochloride for the treatment of recurrent oral ulcers.The ROUMN patch shows enhancement in both the anti-inflammatory effect elicited by dexamethasone and the pro-proliferation effect of vitamin C.In vitro experiments show that ROUMN has a higher efficiency in suppressing lipopolysaccharide(LPS)-induced interleukin-6(IL-6)expression than dexamethasone alone.Cell proliferation and migrationwere also significantly promoted byROUMNcompared to vitamin C alone.The healing-promoting effect of ROUMN was also verified in vivo using an acetic acid-cauterized oral ulcer model in rats.ROUMN as a treatment accelerated the healing process of oral ulcers,shortening the total healing time to 5 days compared with the 7 days required by treatment using watermelon frost,a commonly used over-the-counter(OTC)drug for oral ulcers.The rapid dissolution of the hyaluronic acid-based microneedles and the superior healing-promoting effect of the drug combination could lead to a broad application prospect of the ROUMN patch in the treatment of recurrent oral ulcers.

Genotyping Characteristics of Human Fecal Escherichia coli and Their Association with Multidrug Resistance in Miyun District, Beijing

Objective To explore the genotyping characteristics of human fecal Escherichia coli(E. coli) and the relationships between antibiotic resistance genes(ARGs) and multidrug resistance(MDR) of E. coli in Miyun District, Beijing, an area with high incidence of infectious diarrheal cases but no related data.Methods Over a period of 3 years, 94 E. coli strains were isolated from fecal samples collected from Miyun District Hospital, a surveillance hospital of the National Pathogen Identification Network. The antibiotic susceptibility of the isolates was determined by the broth microdilution method. ARGs,multilocus sequence typing(MLST), and polymorphism trees were analyzed using whole-genome sequencing data(WGS).Results This study revealed that 68.09% of the isolates had MDR, prevalent and distributed in different clades, with a relatively high rate and low pathogenicity. There was no difference in MDR between the diarrheal(49/70) and healthy groups(15/24).Conclusion We developed a random forest(RF) prediction model of TEM.1 + baeR + mphA + mphB +QnrS1 + AAC.3-IId to identify MDR status, highlighting its potential for early resistance identification. The causes of MDR are likely mobile units transmitting the ARGs. In the future, we will continue to strengthen the monitoring of ARGs and MDR, and increase the number of strains to further verify the accuracy of the MDR markers.

Meta‑analysis of influencing factors associating with treatment outcome of multidrug resistant tuberculosis

Objective:To systematically review the influencing factors of the treatment outcome of multidrug-resistant pulmonary tuberculosis and provide reference for the prevention and treatment of multidrug-resistant pulmonary tuberculosis.Method:Case control studies on the factors influencing the treatment outcome of multidrug-resistant pulmonary tuberculosis in Chinese databases(CNKI,VIP,Wanfang,Sinomed)and English databases(Pubmed,Web of science,Medline,Embase,Scopus)were searched and collected by computer.The search period was from the establishment of the database to January 2023.After screening and quality evaluation,RevMan5.4 was used for meta-analysis.Result:Totally 18 articles were ultimately included,with a sample size of 7328 people.The results showed that retreatment,complications,adverse reactions,and gender were related to the treatment outcome of multidrug-resistant pulmonary tuberculosis.The OR values and 95%CI of each factor were 0.22(0.17-0.29),0.38(0.32-0.46),0.27(0.17-0.44),and 0.43(0.33-0.56),respectively.Conclusion:Complications,retreatment,adverse reactions,and male gender are effective risk factors for the treatment outcome of multidrug-resistant pulmonary tuberculosis.In clinical practice,more targeted measures are needed for different types of patients.Due to the limitations of the number of studies,the above conclusions require more research to support them.

Sensorineural Hearing Loss in Multidrug-Resistant Tuberculosis Patients in Kinshasa (Democratic Republic of Congo): Prospective Cohort Study of Therapeutic Regimen with Aminoglycoside versus Bedaquiline

Context: Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem in developing countries such as the Democratic Republic of Congo (DRC), which continues to face the emergence of MDR-TB cases. Because of the ototoxic effects of AGs, the World Health Organization (WHO) has recommended the introduction of the bedaquiline regimen. However, very few data are available regarding the susceptibility of bedaquiline to induce hearing loss, hence the present study set out to compare the AG-based regimen and the bedaquiline-based regimen in the occurrence of hearing loss in MDR-TB patients. Methods: This is a prospective multicenter cohort study that included 335 MDR-TB patients, performed in Kinshasa (DRC) during the period from January 2020 to January 2021. Sociodemographic, clinical, biological and audiometric data were analyzed using Stata 17. Repeated-measures analysis of variance was used to compare changes in the degree of hearing loss over time between the two groups of patients on AG and bedaquiline regimens. The double-difference method was estimated using regression with fixed-effects. A p value < 0.05 was considered the threshold for statistical significance. Results: The degree of hearing loss was similar between the two groups at the first month [AGs (28 dB) vs BDQ (30 dB);p = 0.298]. At six months, the mean degree of hearing loss was significantly greater in the aminoglycoside regimen group [AGs (60.5 dB) vs BDQ (44 dB);p < 0.001]. The double difference was significant, with a greater increase in hearing loss in the AGs group (diff-in-diff 18.3;p < 0.001). After adjustment for age and serum albumin, the group receiving the AG-based regimen had a 2-point greater worsening than those with bedaquiline at the sixth month (diff-in-diff 19.8;p Conclusion: Hearing loss is frequent with both treatment regimens, but more marked with the Aminoglycoside-based regimen. Thus, bedaquiline should also benefit for audiometric monitoring in future MDR-TB patients.

Determinants of the Sensorineural Hearing Loss in Patients with Multidrug-Resistant Tuberculosis in Kinshasa (Democratic Republic of the Congo): A Prospective Cohort Study

Background: The onset of the hearing loss is a major challenge during the treatment of multidrug-resistant tuberculosis (MDR-TB). Aminoglycoside-based regimens, to a lesser extent based on bedaquiline, induce ototoxic sensorineural hearing loss. Research on risk factors is essential to enable high-risk individuals to benefit from preventive measures in settings with limited resources. Objective: This study aimed to assess the determinants of the hearing loss in patients with MDR-TB. Methods: This prospective multicenter cohort study included 337 patients with MDR-TB. It was performed in Kinshasa (Democratic Republic of the Congo) between January 2020 and January 2021. Sociodemographic, clinical, biological, therapeutic, and audiometric data were exported and analyzed using Stata 17 and MedCalc. The fixed-effect linear regression panel model was used to assess the degree of the hearing loss over time according to the following covariates: therapeutic regimen (aminoglycosides, bedaquiline, or alternate), stage of chronic kidney disease (CKD), age at inclusion, body mass index, serum albumin level, HIV status, alcohol intake, hypertension, and hemoglobin level. The Hausman test was used to select between fixed- and random-effect estimators. The threshold for statistical significance was set at p Result: A total of 236 patients (70%) received an aminoglycoside-based regimen, 61 (18%) received a bedaquiline-based regimen, and 40 (12%) received aminoglycosides relayed by bedaquiline. The frequency of the hearing loss increased from 62% to 96.3% within six months for all therapeutic regimens. The Hearing loss worsened, with moderate (72.4%) and profound (16%) deafness being predominant. An Exposure to the treatment for more than one month (β coeff: 27.695, Se: 0.793, p β coeff: 6.102, Se: 1.779, p β coeff: 5.610, Se: 1.682, p = 0.001), and an eGFR β coeff: 6.730, Se: 2.70, p = 0.013) were the independent risk factors associated with the hearing loss in patients with MDR-TB. Conclusions: The Hearing loss was more prevalent and worsened during the treatment of the patients with MDR-TB. An Exposure for more than one month, AG-based regimens, advanced age, hypoalbuminemia, and CKD have emerged as the main determinants of the worsening of the hearing loss.

Influence of efflux pump inhibitors on the multidrug resistance of Helicobacter pylori

AIM:To evaluate the effect of efflux pump inhibitors (EPIs) on multidrug resistance of Helicobacter pylori (H. pylori).METHODS: H. pylori strains were isolated and cultured on Brucella agar plates with 10% sheep's blood. The multidrug resistant (MDR) H. pylori were obtained with the inducer chloramphenicol by repeated doubling of the concentration until no colony was seen, then the susceptibilities of the MDR strains and their parents to 9 antibiotics were assessed with agar dilution tests. The present study included periods before and after the advent of the EPIs, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), reserpine and pantoprazole), and the minimum inhibitory concentrations (MICs) were determined accordingly. In the same way, the effects of 5 proton pump inhibitors (PPIs), used in treatment of H. pylori infection, on MICs of antibiotics were evaluated.RESULTS: Four strains of MDR H. pylori were induced successfully, and the antibiotic susceptibilities of MDR strains were partly restored by CCCP and pantoprazole, but there was little effect of reserpine. Rabeprazole was the most effective of the 5 PPIs which could decrease the MICs of antibiotics for MDR H. pylori significantly.CONCLUSION: In vitro, some EPIs can strengthen the activities of different antibiotics which are the putative substrates of the efflux pump system in H. pylori.

Survey of Multidrug Resistance and Class I Integron Prevalence in Chicken-derived Salmonella

[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells,

Structure-activity Relationship of Phenothiazines for Inhibition of Protein Kinase C and Reversal of Multidrug Resistance

Studies on structure-activity relationship of phenothiazines (PTZs) forinhibition of protein kinase C (PKC) and reversal of multidrug resistance (MDR) has been made invitro. The results showed that the order of potency of reversal effect of PTZs on MDR is as follows:2-COC_3 H_7 > 2-CF_3 > 2-COCH_3 > H. The type of piperazinyl substitution also significantlyaffected potency against MDR. The results show the order: CH_3 > COOC_2 H_5 > C_2 H_4 OH. Inaddition, PKC plays a marked role in diverse cellular process including MDR. Some derivatives of PTZwas tested for inhibition of PKC, of which PTZ11 showed the highest inhibitory effect of MDR andPKC, implying a potential reversal agent of MDR for tumor therapy in the future. We also tried toexplore the possible binding model of PTZs to PKC. Our molecular-modeling study preliminarilysuggests how these PTZs bind to PKC and provides a structural basis for the design of high affinityPKC-modulator. The infor-mation may be used in the rational design of more effective drugs.

Using ^(99m)Tc-MIBI to Evaluate the Effects of Chemosensitizer on P-glycoprotein in Multidrug-resistant Carcinoma Cells

To establish a method to evaluate the effects of chemosensitizer onP-glycoprotein using ^(99m)Tc-MIBI, and observe the changes of ^(99m)Tc-MIBI uptake kinetics andP-glycoprotein levels after using verapamil in MDR human breast cells MCF-7/Adr. Methods: MDR breastcarcinoma cells, MCF-7/Adr, were incubated and different protocols were performed. Protocol Ⅰ: achemosensitizer, verapamil (10 μmol/L), was added into cell culture medium, while in control group,the same volume of DMEM was given. Cells were harvested after 2 h incubation with ^(99m)Tc-MIBI.Protocol Ⅱ: Verapamil (10 μmol/L) was added into cell culture medium and incubated for 20 min, 40min, 60 min, 80 min, 8 h, 24 h, 48 h and 72 h respectively. Cells were harvested after 2 hincubation with ^(99m)Tc-MIBI. The radioactivity of the cells was measured and P-glycoproteinexpression levels were determined with immunohistochemical stain. Results: Protocol Ⅰ: After 2hincubation with verapamil the cellular uptake of ^(99m)Tc-MIBI was remarkably higher than controlgroup (t=2.33, P 【 0.05), but there was no difference in P-glycoprotein expression levels betweentwo groups (P 】 0.05). Protocol Ⅱ: In verapamil group, ^(99m)Tc-MIBI uptake was increased withincubation time prolonging (F=58.2, P 【 0.05). When verapamil incubation time surpassed 8 h the^(99m)Tc-MIBI uptake negatively correlated to the P-glycoprotein expression levels (r=-0.73, P 【0.01). However, when incubation time was less than 80 min, there was no correlation between^(99m)Tc-MIBI accumulation and P-glycoprotein levels (r=0.16, P 】 0.05). Conclusion: ^(99m)Tc-MIBImay be used to evaluate the qualitative as well as quantitative change of P-glycoprotein expressionlevels induced by the chemosensitizer, verapamil.

Reversal of Multidrug Resistance by Neferine in Adriamycin Resistant Human Breast Cancer Cell Line MCF-7/ADM

Objective: To study the reversal effect of neferine on adriamycin (ADM) resistant human breast cancer cell line MCF-7/ADM. Methods: The cytotoxic effect of Nef or ADM was determined by 3-[4, 5-dimethylthiazol-2.-yl], 5-diphenyl tetraxolium bromid (MTT) assay. Apoptosis and the expression of P-glycoprotein (P-gp) were detected by flow cytometry (FCM). The intracellular ADM concentration was measured by HPLC. Results: Nef at 1, 5, 10 mol/L decreased the IC50 of ADM to MCF-7/ADM from 11.63 g/mL to 4.59, 2.44, 0.27 g/mL respectively. MCF-7/ADM could resist the apoptosis induced by ADM while Nef (1-10 mol/L) could augment ADR-mediated apoptosis. Nef (10 mol/L) increased the accumulation of ADM up to 2.88 fold in MCF-7/ADM but not in sensitive cells MCF-7/S and reduced the expression of P-gp in MCF-7/ADM cells. Conclusion: Nef can circumvent multidrug resistance (MDR) of MCF-7/ADM cells and the mechanism was associated with the increase of intracellular accumulation of ADM and the reduced expression of P-gp in MCF-7/ADM cells.

EXPRESSION AND CLINICAL SIGNIFICANCE OF MULTIDRUG RESISTANCE GENE AND MULTIDRUG RESISTANCE-ASSOCIATEDPROTEIN GENE IN ACUTE LEUKEMIA

Objective: To evaluate the expression and clinical significance of multidrug resistance gene (mdr1) and multidrug resistance-associated protein (MRP) gene in acute leukemia. Methods: The expression of mdr1 and MRP assay in 55 patients with acute leukemia (AL) by reverse transcription polymerase chain reaction (RT-PCR). Results: The mdr1 and MRP gene expression levels in the relapsed AL and the blastic plastic phases of CML were significantly higher than those in the newly diagnostic AL and controls. The mdr1 and MRP gene expression levels in the clinical drug-resistant group were significantly higher than those in the non-drug-resistant group. The complete remission (CR) rate in patients with high mdr1 expression (14.3%) was significantly lower than that with low mdr1 expression (57.5%); similarly the CR rate in patients with high MRP level was also lower than that with low MRP level. Using both high expression of mdr1 and MRP gene as the indicator for evaluating multidrug resistance (MDR), the positive predictive value and accuracy increased in comparison with single gene high expression. Conclusion: Elevated level of mdr1 or MRP gene expression might be unfavorable prognostic factors for AL patient and may be used as an important index for predicting drug-resistance and relapse in AL patient. Measuring both mdr1 and MRP gene expression would increase accuracy and sensibility of evaluating MDR in acute leukemia.

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.

Antimicrobial peptides: new hope in the war against multidrug resistance

The discovery of antibiotics marked a golden age in the revolution of human medicine. However,decades later, bacterial infections remain a global healthcare threat, and a return to the pre-antibiotic era seems inevitable if stringent measures are not adopted to curb the rapid emergence and spread of multidrug resistance and the indiscriminate use of antibiotics. In hospital settings, multidrug resistant(MDR) pathogens, including carbapenem-resistant Pseudomonas aeruginosa, vancomycin-resistant enterococci(VRE), methicillin-resistant Staphylococcus aureus(MRSA), and extendedspectrum β-lactamases(ESBL) bearing Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae are amongst the most problematic due to the paucity of treatment options,increased hospital stay, and exorbitant medical costs. Antimicrobial peptides(AMPs) provide an excellent potential strategy for combating these threats. Compared to empirical antibiotics, they show low tendency to select for resistance, rapid killing action, broad-spectrum activity, and extraordinary clinical efficacy against several MDR strains. Therefore, this review highlights multidrug resistance among nosocomial bacterial pathogens and its implications and reiterates the importance of AMPs as next-generation antibiotics for combating MDR superbugs.

Inhibitory effects of emodin, baicalin, schizandrin and berberine on hef A gene: Treatment of Helicobacter pylori-induced multidrug resistance

AIM: To investigate the inhibitory effects of emodin, baicalin, etc.on the hefA gene of multidrug resistance(MDR) in Helicobacter pylori(H.pylori).METHODS: The double dilution method was used to screen MDR H.pylori strains and determine the minimum inhibitory concentrations(MICs) of emodin, baicalin, schizandrin, berberine, clarithromycin, metronidazole, tetracycline, amoxicillin and levofloxacin against H.pylori strains.After the screened MDR stains were treated with emodin, baicalin, schizandrin or berberine at a 1/2 MIC concentration for 48 h, changes in MICs of amoxicillin, tetracycline, levofloxacin, metronidazole and clarithromycin were determined.MDR strains with reduced MICs of amoxicillin were selected to detect the hefA mR NA expression by realtime quantitative PCR.RESULTS: A total of four MDR H.pylori strains were screened.Treatment with emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some strains, decreased by 1 to 2 times, but did not significantly change the MICs of clarithromycin, levofloxacin, and metronidazole against MDR strains.In the majority of strains with reduced MICs of amoxicillin, hef A m RNA expression was decreased; one-way ANOVA(SPSS 12.0) used for comparative analysis, P < 0.05.CONCLUSION: Emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some H.pylori strains, possibly by mechanisms associated with decreasing hefA mR NA expression.