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.
【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 analyze the clinical and etiological characteristics and bacterial susceptibility in patients with ventilator-associated pneumonia (VAP) in Guangzhou area.Methods A retrospective study was conducted on VAP patients in four hospital of Guangzhou from Jan 2004 to Oct 2005.Totally 157 patients were enrolled in this study，whose flora was identified and tested by Kirby Bauer disk diffusion susceptibility test.The univariate analysis method was used to analyze the prognostic parameters.Results The average onset time of VAP was 7.7 days after mechanical ventilation with a mortality rate of 38.2%.The proportion of Gram-negative bacilli，Gram-positive cocci and eumycete was 68.0%，23.4% and 8.7% respectively in 184 isolated strains.The most common pathogens were Pseudomonas aeruginosa (18.5%)，Stenotrophomonas maltophilia (14.1％)，Burkholderia cepacia (10.9%)，Staphylococcus aureus (10.3%) and Acinetobacter baumannii (8.7%).Pseudomonas aeruginosa，Stenotrophomonas maltophilia，and Acinetobacter baumannii were resistant to most common antibacterials such as cephalosporin and imipenem.18 strains oxacillin resistant Staphylococcus aureus，7 strains oxacillin resistant Staphylococcus simulans and one vancomycin resistant Staphylococcus aureus were isolated.Expect for vancomycin，teicoplanin and fusidic acid，the resistance of Gram-positive cocci were above 50% to other 9 antibacterials.Conclusions The antibiotic resistance situation of VAP in Guangzhou is very serious with high mortality.It is important to reinforce the prevention and guidance on the proper treatment of VAP.
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 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.
Objective To investigate the drug resistance and homogeneous analysis of Acinetobacter baumanii in emergency intensive care unit ( EICU) . Methods Four multidrug-resistant Acinetobacter baumannii ( MDR-Ab) strains isolated fromnosocomial inpatients fromJuly 25 to September 7 in 2009 were collected and tested for drug sensitivity and MIC determination as well. The A. baumannii isolates were typed with pulsed-field gel electrophoresis ( PFGE) to determine whether they derived fromthe same clone.Results Four isolates from nosocomial inpatients were resistant to multiple antibiotics including carbapenem. The PFGE types identified from four isolates were A and B. The A. baumannii isolates did not derived from the same clone. Conclusion The prevalence of nosocomial infection is not due to transmission of the same strains among different individuals in EICU.
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 observe the regional expression of hypoxia inducible factor-1alpha; (HIF-1alpha;) in retinoblastoma and its relationships with vascular endothelial growth factor (VEGF), Bax and Ki-67. Methods Immunohistochemical study for HIF-1alpha;, VEGF, Bax and Ki-67 was performed in 39 paraffinaceous examples of retinoblastoma. Each pathological section was divided into five regions: the surface region, the central part, the bottom part, the choroidal region and seeding tumors. The expressions, correlations and distributional differences of these factors were all invested both integrally and regionally. Results In the 39 cases of retinoblastoma, 10 cases (25.6%) were negative for HIF-1alpha;; 29 cases (74.4%) were positive for HIF-1alpha;, including 17 cases (43.6%) (+), 12 cases (30.8%) (++). Regionally, HIF-1alpha; was positive in 71.1%, 36.8%, 84.2%, 54.5% and 82.1% of the cases in the surface region, the central part, the bottom part, the choroidal region and seeding tumors, respectively, which was statistically reliable (chi;2=24.55，P＜0.001). The positive rate of VEGF, Bax and Ki-67 was 53.8%, 66.7% and 59.0%, respectively. In different regions, the positive rates of VEGF and Bax were different (chi;2=26.77, 22.79; P＜0.001), but there was no regional distinctions in the expression of Ki-67 (chi;2=0.47, P=0.976). Both the expression of VEGF and Bax had a positive correlation with that of HIF-1alpha;(rs=0.48, 0.39; P=0.002, 0.021), but there was no relationship between the expressions of Ki-67 and that of HIF-1alpha; (rs=0.09, P=0.606). Regionally, the expressions of VEGF, Bax and HIF-1alpha; shared similar distributional features: positive rates were higher in the surface region, bottom part and seeding tumors, and were lower in the central part and choroidal region, which was different from the expression of Ki-67. Conclusion The anoxic zones are more likely to be located in the marginal parts in retinoblastoma, and the expressions of VEGF and Bax had a positive correlation with that of HIF-1alpha; in different regions in retinoblastoma.
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.
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.