【Abstract】ObjectiveTo establish adriamycin (ADM) resistant pancreatic cancer cell line SW1990/ADM and to investigate its drug resistance mechanism.MethodsADM-resistant pancreatic cancer cell line SW1990/ADM was obtained by culture of pancreatic cancer cell line SW1990 in vitro with intermittently increasing the concentration of ADM in the culture medium for ten months. After two months of drug free culture, its biological characteristics, drug sensitivity as well as the expression and function of multidrug resistant gene 1 (mdr1) were detected, respectively. ResultsCompared with the parental cell line, SW1990/ADM showed great changes in biological characteristics and developed a cross resistance to various chemotherapy drugs. The drug resistance indexes of cell line SW1990/ADM to ADM, mitomycin, fluorouracil and gemcitabine were 49.60, 7.25, 3.80 and 1.25, respectively. The level of mdr1 mRNA expression in cell line SW1990/ADM was much higher than that of the parental cell line（P＜0.01). ConclusionWe have established adriamycin resistant pancreatic cancer cell line SW1990/ADM with multidrug resistance phenotype, its multidrug resistance is positively relevant to the expression of mdr1.
Objective To observe the effect of resveratrol on multidrug resistance (MDR) in human retinoblastoma cells treated. Methods RB cells in logarithmic growth phase were divided into experimental group and control group. RB cells in experimental group were cultured with different concentrations of resveratrol (6.25, 12.50, 25.00, 50.00, 100.00 mu;mol/L) for 24 and 48 hours. The proliferation (absorbance value) was assayed using methyl thiazolyl tetrazolium (MTT). RB cells were cultured with 50.00 mu;mol/L resveratrol for 48 hours. The expressions of MDR-1, cyclooxygenase-2 (COX-2)、multidrug resistance-associated protein-1 (MRP-1), glutathione-S-transferases-pi; (GST-pi;) were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The RB cells of the control group were cultured with 0.5% dimethyl sulfoxide. Results Compared with the control group, the absorbance value decreased in experimental groups (6.25, 12.50, 25.00, 50.00 mu;mol/L) in a dose dependent manner (F=4.782，P＜0.05). The difference of absorbance value between 50.00 and 100.00 mu;mol/L experimental groups was not significant (F=6.351,P＞0.05). Compared with the control group, the mRNA (t=9.170, 5.758, 4.152, 4.638) and protein (t=3.848, 5.955, 4.541, 3.514) expression levels of MDR-1, MRP1, COX-2, and GST-pi; decreased in the experimental group (P＜0.05). Conclusion Resveratrol can down-regulate the expression of MDR in RB cells.
Objective To explore the clinical epidemiological characteristics of the lung infection after orthotopical liver transplantation. Methods The clinical data included infection morbidity, mortality, infectious times and relative factors, clinical manifestations, the bacterial strains and distributions of the pathogens, the bacterial resistances of the 53 liver transplantation recipients from 2003.3～2006.12 were summarized and analyzed retrospectively. Results Among 53 recipients, 33 developed lung infectious and 6 died .The mobidity was 62.3% and mortality was 18.2%, with a OR of 1.0. Lung infection predominantly occurred in the first month, especially in the first week after transplantation.There were many factors related to lung infections.Various pathogens, especially Klebsialla, Escherichia Coli and Staphylococus Hominis were isolated from sputum, airway suction drainages and throat swabs. Most of the G- bacteria were sensitive to aminoglycosides,β lactam and lactamase compounds and carbapenems while G+ bacteria were sensitive only to glycopeptides. All the bacteria were resistant to quinolones, β lactams of third and forth generation. Conclusions After liver transplantation, the morbidity and mortality of the lung infections are high.The infections develope at earlier stage, manifest nontypical clinical features.Many factors are revealed to be relevant to the lung infections,meanwhile, various drug-resistant pathogen strains are isolated.
Objective To establish a xenograft model of hydroxycamptothecine (HCPT)-resistant human gastric cancer cell line (SGC-7901/HCPT) in nude mice and study its biological characteristics. Methods The SGC-7901 and SGC-7901/ HCPT cells were cultured in vitro. The cell suspension was injected subcutaneously into the nude mice. When the subcutaneous carcinoma was 1.0 cm in diameter, it was cut off and divided into pieces of 0.1-0.2 cm in diameter． Then the small pieces of tumor were re-transplanted subcutaneously into the second generation nude mice until the fourth generation. The morphological feature, ultramicro-structure, and growth characteristics of the fourth generation transplanted tumor were examined. The drug resistance was measured by methyl thiazolyl tetrazolium (MTT) assay. Results The transplanted tumor in nude mice was round or oval, and many blood vessels were on its surface. Under the light microscope, the sizes of SGC-7901 transplanted tumor cells were similar, and sizes of cell nuclei were also similar; Meanwhile, the morphous of SGC-7901/HCPT transplanted tumor cells were irregular and in disorder, and the size of the cell nuclei was different from each other. Under the electron microscope, the mitochondria and endoplasmic reticulum of SGC-7901 transplanted tumor cells were nearly normal and no swelling in cell nuclei; Meanwhile the cell nuclei of SGC-7901/HCPT transplanted tumor cells were lightly swelled, a the mitochondria and endoplasmic reticulum were obviously swelled. By MTT assay, compared with SGC-7901 transplanted tumor cells, the resistance index of SGC-7901/HCPT transplanted tumor cells was 9.02±0.78 in HCPT, and resistance index to Adriamycin， Mitomycin C, 5-fluorouracil, and Etoposide was 1.24±0.09, 1.31±0.17, 0.96±0.12, and 1.07±0.16, respectively. Conclusions A transplanted tumor model of SGC-7901/HCPT in nude mice is established successfully， and showing stable drug resistance to HCPT and no cross-resistance to other chemotherapeutics, which can be used for further experiments.
Objective To investigate the initial drug resistance of Mycobacterium tuberculosis ( M.tuberculosis) in patients with culture positive pulmonary tuberculosis. Methods 1184 patients who hospitalized in Shandong Provincial Chest Hospital with culture positive pulmonary tuberculosis were enrolled. The absolute density method was used to assess the drug resistance of M. tuberculosis. Results M.tuberculosis were sensitive to all anti-tuberculosis drugs in 834 cases( 70. 44% ) , and resistant in 350 cases( 29. 56% ) , in which initial resistance and secondary resistance accounted for 44. 86% ( 157/350) and 55. 14% ( 193 /350) respectively. In 157 cases with initial resistance, 53 cases ( 33. 8% ) were mono-drug resistant tuberculosis( MonoDR-TB) , of which 38 cases were resistance to Streptomycin( 24. 2% ) ; 72 cases( 45. 9% ) were polydrug-resistant tuberculosis ( PDR-TB) ; 20 cases ( 12. 7% ) were multidrug-resistant tuberculosis ( MDR-TB) ; 12 cases ( 7. 6% ) were extensively drug resistant tuberculosis ( XDR-TB) . There was no totally drug-resistant tuberculosis ( TDR-TB) . Conclusions The initial drug resistance of M.tuberculosis in patients with pulmonary tuberculosis is still serious. Unified management of TB control programs and full supervision of chemotherapy are very imperative.
ObjectiveTo provide the evidence for diagnosis and treatment of the complication by describing the distribution and drug sensitivity of pathogens in patients with prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA). MethodsBetween January 2003 and June 2013,65 cases (65 knees) with PJI after primary TKA were treated.There were 28 males and 37 females with an average age of 63.2 years (range,37-80 years).The median interval between PJI and primary TKA was 2.8 years (range,2 weeks to 11 years),including 29 left knees and 36 right knees.Prosthesis loosening could be found in 27 cases by X-ray examination.The average value of C-reactive protein and erythrocyte sedimentation rate was 37.4 mg/L (range,12.5-197.0 mg/L) and 63.2 mm/1 h (range,29.3-73.8 mm/1 h) respectively.Preoperative and intraoperative synovial fluid as well as intraoperative tissue samples should be submitted for aerobic and anaerobic culture.The four types of infections were made according to the Tsukayama et al.classification standards. ResultsThe patients were all diagnosed as having PJI.There were 5(7.69%) type I infections,4(6.15%) type ⅡA,8(12.31%) type ⅡB,3(4.62%) type Ⅲ,and 45(69.23%) type IV according to the Tsukayama et al.classification standard.Bacterial culture results were negative in 12 cases and positive in 53 cases,the main pathogen was Gram-positive cocci (39/53).The most common organism identified was Coagulase-negative Staphylococcus (24/53) followed by Staphylococcus Aureus (12/53).Resistant bacterium accounted for 61.11%(22/36) of Staphylococcus.These bacterium were all sensitive to vancomycin,linezolid,meropenem,and fluconazole;and highly resistant to erythrocin,penicillin,and cefoxitin.The main pathogenic bacteria of Coagulase-negative Staphylococcus and Staphylococcus aureus had highest resistant rate to penicillin. ConclusionGram-positive cocci is the main pathogen in patients with PJI after primary TKA,which is highly resistant to penicillin and macrolides.Antibiotic treatment of this complication should be based on the result of drug sensitivity test,vancomycin and linezolid may be used before the result of drug sensitivity test.It is important to pay attention to rare and multiple resistant bacteria.
Objective To summarize the roles of tumor initiating cells （TICs） and epithelial-mesenchymal transition （EMT） in tumor metastasis and drug resistance. Methods Domestic and international publications online which involving TICs，EMT，and its roles in tumor metastasis and drug resistance in recent years were reviewed. Results TICs were self-renewal cells and had the ability to give rise to more differentiated cell types，and played an important role in tumor metastasis and drug resistance. Various markers had been used to identify TICs，such as CD133，CD44，and so on. EMT was the process by which epithelial cells losed polarity and detach from the epithelial sheet， and acquired a motile mesenchymal phenotype，usually observed in embryo development and wound healing. It also could promote tumor progression and metastasis，and may also be responsible for the ability of tumors to evade the body’s immune response. EMT may be the reasons of TICs that drived tumor metastasis and recurrence. TICs or EMT as a target for treatments may effectively prevent tumor recurrence and improve patient’s survival. Conclusions EMT is probably the mechanism that TICs promote tumor metastasis and drug resistance. More effective target therapies for cancer may be found if we know more about TICs and EMT.
0bjective To compare the effect of closed airway management system and open suction system on distribution and drug susceptibility of pathogenic bacteria in lower respiratory tract of mechanical ventilated patients.Methods Fifty-nine cases in ICU who received mechanical ventilation for more than 48 h from May 2006 to Dec 2006 were randomly divided into two groups.Group A(29 patients)received closed—tracheal suction and Group B(30 patients)received open-tracheal suction.Quantitative bacteriological culture and sensitivity of antibacterial drugs were conducted on lower respiratory tract secretion samples.Results In group A，a total of 91 strains were isolated，in which a single pathogen infection(41.4％)was the most frequent，followed by mixed infection of two pathogens(34.5％)and three or more pathogens(24.1％).In group B，a total of 141 strains were isolated，in which three or more pathogen infection(53.33％)was the most frequent，followed by two pathogen infection(30％)and a single pathogen infection(16.7％ ).Pathogen distribution between the two groups was not significantly different(Pgt;0.05).Drug susceptibility test did not show significant difference in main pathogens between the two groups(Pgt;0.05).Conclusions Closed airway management system can reduce the infection or colonization of mixed pathogens，but can not change the distribution and drug susceptibility of pathogens.
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.
ObjectiveTo investigate the condensate pollution in the pipeline of severe pneumonia patients undergoing mechanical ventilation.MethodsFrom January 2017 to January 2019, 120 patients with severe pneumonia treated by mechanical ventilation in our hospital were collected continuously. The lower respiratory tract secretions were collected for bacteriological examination. At the same time, the condensed water in the ventilator exhaust pipe was collected for bacteriological examination at 4, 8, 12, 16, 20 and 24 hours after tracheal intubation and mechanical ventilation. The bacterial contamination in the condensed water at different time points was analyzed and separated from the lower respiratory tract. The consistency of bacteria in secretion and drug resistance analysis of bacterial contamination in condensate water were carried out.ResultsOf the 120 patients with severe pneumonia after mechanical ventilation, isolates were cultured in the lower respiratory tract secretions of 102 patients. One strain was cultured in 88 cases, two strains were cultured in 10 cases, and three strains were cultured in 4 cases. The isolates were mainly Gram-negative bacteria (57.5%) and Gram-positive bacteria (42.5%). The most common isolates were Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter baumannii. The contamination rate of condensate water was 5.0% at 4 hours, 37.5% at 8 hours, 60.0% at 12 hours, 76.7% at 16 hours, 95.0% at 20 hours, and 100.0% at 24 hours, respectively. The bacterial contamination rate in condensate water at different time points was statistically significant (P=0.000). The pollution rate at 4 hours was significantly lower than that at 8 hours (P=0.000). Gram-negative bacteria accounted for 57.5% and Gram-positive bacteria accounted for 42.5%. The most common isolates were Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. The consistency of bacteria in lower respiratory tract and condensate water was 83.3% in severe pneumonia patients undergoing mechanical ventilation. The overall resistance of Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus aureus was higher, but the resistance to imipenem/cilastatin was lower.ConclusionsThe bacterial contamination in the condensate of patients with severe pneumonia during mechanical ventilation is serious. The pollution rate is low within 4 hours. It is consistent with the bacterial contamination in lower respiratory tract and the bacterial resistance is high.