Objective To review the application advancements of ATP-binding cassette (ABC) transporter in medical research.Methods Relevant literatures about the applications of ABC families in medical research were reviewed. Results ABC families mainly took roles in transporting substances across cell membrane. Some of them were useful for the prediction of drug resistance and the prognosis of malignant tumors. Others were target s for molecular researches. Their expressions or mutations might be related with the occurrence of diseases. Conclusion ABC families are very important in the diagnosis and therapy for diseases. Thus they are very promising tools for future medical research.
ObjectiveTo construct the recombinant adenovirus vector carrying antisense multidrug resistanceassociated protein (MRP) and transfect the human drugresistant hepatocellular carcinoma cell line(SMMC7721/ADM). MethodsThe fragment of MRP gene encoding 5′region was cloned reversely into the shuttle plasmid pAdTrackCMV, with the resultant plasmid and the backbone plasmid pAdEasy1,the homologous recombination took place in the bacteria and the recombinant adenoviral plasmid was generated. The adenoviruses were packaged and amplified in 293 cells. Then the cell line of SMMC7721/ADM was transfected with the resultant adenoviruses.ResultsThe recombinant adenovirus vector carrying antisense MRP was constructed successfully. The viral titer was 2.5×109 efu/ml, and more than 90% SMMC7721/ADM cells could be transfected when the multiplicity of infection（MOI） was 100. ConclusionThe recombinant adenovirus vector constructed by us could introduce the antisense MRP into the human drugresistant hepatocellular cell line effectively, which would provide experimental basis for the mechanisms and reversal methods of the multidrug resistance in human hepatocellular carcinoma.
Objective To investigate the reversal effect of antisense phosphorothioate oligonucleotide （ASOND) on human hepatoma resistant cells. Methods Human hepatoma resistant cells SMMC-7721 was transfected with synthetic antisense phosphorothioate oligonucleotide complementary to the 5′ region flanking the AUG initiation codon mediated by lipofectamine. In vitro drug sensitivity was measured by MTT assay. The expression of P-170 was determined by flow cytometry and mRNA was assessed by RT-PCR. Results ASOND inhibited the expression of mRNA and p-170 in SMMC-7721, enhanced the sensitivity of SMMC-7721 to chemotherapeutic drug. The best inhibitory effect was achived by the dose of 0.5μmol/L. Conclusion ASOND enhanced the sensitivity of SMMC-7721 to chemotherapeutic drug and reversed the multidrug resistance of SMMC-7721 partially.
ObjectiveTo establish multidrugresistance cell substrain of human hepatocellular carcinoma and to investigate its characteristics.MethodsSMMC7721 cell strain was cultured in Adriamycin(ADM). The multidrugresistance cell substrain SMMC7721/ADM was harvested after a long period of culture by gradually increasing the concentration of ADM and its characteristics were investigated. Results①The drug resistance of SMMC7721/ADM to ADM increased by 33.3 times, to Vincristine 16.8 times, to Diamminedichloroplatinum 2.8 times. ②The drug resistance cell substrain had almost the same growth velocity as its parental generation. The doubling time was 32.0 hours and 30.5 hours respectively. They had the analogous growth curves. ③The obvious difference between the drug resistance cell substrain and its parental generation was that the former’s microvilli became thick, short and scattered by scanning and transmitting electron microscopy. ④The multidrug resistance cell substrain kept the characteristics of hepatocellular carcinoma, it could be transplanted into the subcutaneous tissue of nude mice. ⑤The drug resistance of the cell substrain reduced to 28.0% and 9.2%after removal of the drug for 1 month and 2 months respectively, its drug resistance could remain stable (35.4 times) after 2 months of culture in ADM (0.04 μg/ml).ConclusionThe SMMC7721/ADM cell substrain has the stable fundamental characteristics of a drug resistance cell strain.
ObjectiveTo systematically review the efficacy and safety of ginseng preparations in improving insulin resistance (IR). MethodsWe electronically searched databases including PubMed, MEDLINE, EMbase, CNKI, VIP, WanFang Data, and CBM from inception to October 2015, to collect randomized controlled trials (RCT) about ginseng preparations for IR patients. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. Then meta-analysis was performed using RevMan 5.3 software. ResultsA total of 17 RCTs involving 1169 patients were included. The results of meta-analysis showed that treatment combined with ginseng preparations group was superior to the control group in levels of HOMA-IR (MD=-0.13, 95%CI -0.24 to -0.01, P=0.03), ISI (MD=0.72, 95%CI 0.25 to 1.19, P=0.003), FPG (MD=-0.90, 95%CI -1.27 to -0.52, P<0.00001), 2hPG (MD=-1.48, 95%CI -2.03 to -0.92, P<0.00001) and HbA1c (MD=-0.73, 95%CI -1.16 to -0.31, P=0.0008). No statistically differences between two groups were found in levels of FPI and F-CP. As for the safety, a total of 9 cases in the ginseng group occurred adverse reactions. Symptoms of adverse reactions included hypoglycemia, dizziness, nausea, blurred vision. ConclusionCurrent evidence shows that, treatment combined with ginseng preparations could improve insulin sensitivity and reduce blood glucose in IR patients with type 2 diabetes and metabolic syndrome. Due to limited quality and quantity of the included studies, the above conclusion need to be verified by more high quality studies.
ObjectiveTo investigate the distribution and drug resistance of the pathogens isolated from hospitalized pediatric patients with respiratory tract infections, and to provide guidance for empiric therapy. MethodsRespiratory tract specimens from hospitalized pediatric patients with respiratory tract infections from 2011 to 2015 were collected, and the strains were identified and the drug susceptibility was tested. ResultsA total of 1995 strains of pathogens, 1281 (64.21%) from boys and 714 (35.79%) from girls, were isolated from 6236 specimens and the detection rate was 31.99%. The mean age of the hospitalized pediatric patients was (1.22±2.05) years (ranged from 1 day to 14 years). 1393 (69.82%) pediatric patients were younger than 1 year. Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Candida albicans and Acinetobacter baumannii ranked the top five species, accounting for 29.82%, 15.09%, 13.18%, 12.73% and 5.91%, respectively. 1995 strains included gram-negative bacteria (50.93%), gram-positive bacteria (35.29%), and fungi (13.78%). The resistance rate of Staphylococcus aureus to oxacillin was 31.76%, but it was 100% sensitive to vancomycin and linezolid. The resistant rate of gram-negative bacteria to imipenem was ranged from 1.52% to 5.93%. The resistant rate of gram-negative bacteria to ceftazidime, cefepime, piperacillin tazobactam and tobramycin was less than 30.00%. ConclusionsThe infants whose age are younger than 1 year comprise the majority of the hospitalized pediatric patients with respiratory tract infections. The proportion of male is more than that of female. Staphylococcus aureus and enterobacteriaceae were the main isolated pathogens. There is difference in drug resistance between different pathogens, so antibiotics should be chosen according to the results of drug sensitivity testing.
A three-dimensional finite element model of premaxillary bone and anterior teeth was established with ANSYS 13.0. The anterior teeth were fixed with strong stainless labial archwire and lingual frame. In the horizontal loading experiments, a horizontal retraction force of 1.5 N was applied bilaterally to the segment through hooks at the same height between 7 and 21 mm from the incisal edge of central incisor; in vertical loading experiments, a vertical intrusion force of 1.5 N was applied at the midline of lingual frame with distance between 4 and 16 mm from the incisal edge of central incisor. After loading, solution was done and displacement and maximum principle stress were calculated. After horizontal loading, lingual displacement and stress in periodontal membrane (PDM) was most homogeneous when the traction force was 14 mm from the edge of central incisor; after vertical loading, intrusive displacement and stress in PDM were most homogeneous when the traction force was 12 mm from the incisal edge of central incisor. The results of this study suggested that the location of center of resistance (CRe) of six maxillary anterior teeth is about 14 mm gingivally and 12 mm lingually to incisal edge of central incisor. The location can provide evidence for theoretical and clinical study in orthodontics.
Objective To detect the characteristic of multidrug resistance gene products expressions in gastric cancer tissues, including glutathione-s-transferase π (GST-π), P-glycoprotein (P-gp), topoisomerase Ⅱ (Topo-Ⅱ), thymidylate synthase (TS), and multidrug resistance related protein (MRP), and analyze their clinical significance for the therapy of gastric cancer. Methods SP immunohistochemical stain was used to detect GST-π, P-gp, Topo-Ⅱ, TS and MRP expressions in sample of 48 gastric cancer tissues and 10 normal gastric mucosa. And their corresponding clinical data were comprehensive analyzed. Results The expressions of GST-π, P-gp, Topo-Ⅱ, TS and MRP had notable differences between the gastric cancer tissues and normal gastric mucosa (GST-π： P＜0.01； P-gp： P＜0.01； Topo-Ⅱ： P＜0.01； TS： P＜0.05； MRP： P＜0.05). Positive expression rates of GST-π, P-gp, Topo-Ⅱ, TS and MRP in gastric cancer tissues were 72.9% (35/48), 56.3% (27/48), 83.3% (40/48), 41.7% (20/48) and 39.6% (19/48), and positive expression rates of them in normal gastric mucosa were 10.0% (1/10), 0 (0/10), 0 (0/10), 0 (0/10) and 0 (0/10) corresponding. Their positive expression rates were closely relevant to the degree of differentiation (P＜0.01), but not to the patients’ sex, age, tumour site, size of tumour, invasive depth and lymph node metastasis (Pgt;0.05). Conclusions The expressions of GST-π, P-gp, Topo-Ⅱ, TS and MRP in gastric cancer tissues exist obvious heterogeneity. Their overexpression underlie the multidrug resistance of gastric cancer. The joint detection of GST-π, P-gp, Topo-Ⅱ, TS and MRP can be looked as an important symbol for guiding its chemotherapy.
The issue of bacterial drug resistance has remained unresolved, and in recent years, biomimetic nanostructured surfaces inspired by nature have garnered significant attention due to their bactericidal properties demonstrated through mechanical mechanisms. This article reviewed the main research progress in the field of nanostructured mechanical bactericidal surfaces, including various preparation methods for nanostructured surfaces with mechanical bactericidal properties, as well as the basic mechanisms and related physical models of the interaction between bacteria and nanostructured surfaces. In addition, the application of nanostructured surfaces in biomedicine was introduced. Finally, the article proposed the major challenges faced by mechanical bactericidal research and the future development direction.
This paper proposes a forced oscillation respiration resistance detector which has the characteristics of portable and friendly interface, with remote transmission function. STM32 is used to produce single frequency or complex frequency oscillation signal. In the experiments, the signal was magnified by the power amplifier to drive speaker to generate oscillates airflow into the subject's oral cavity. The analog to digital coverter of STM32 was used to measure the signals obtained by the pressure sensor and the flow sensor, and then the operation parameters were to be displayed on the TFT-LCD touch screen, and could also be transferred to the master computer. Simulated lung and volunteerism were used to verify the reliability of the detector. The test results showed that the system was reliable, and it achieved the significance in respiratory impedance detecting.