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Objective:To investigate epithelial-mesenchymal transition and to explore the effects of mitochondrial dysfunction and increased expression of TGF-β1 pathway on epithelial-mesenchymal transition (EMT) in pancreatic adenocarcinoma after X-ray irradiation.Methods:Split-dose irradiations of total 40 Gy (2 Gy × 20 and 4 Gy × 10) of 6 MV X-rays were performed on PATU1 988 t cells. The migration of the cells were examined through transwell filter chambers. Real-time PCR was adopted to detect the expression of EMT-related factors E-cadherin, Vimentin, N-cadherin, and MMPs (MMP2 and MMP9), critical subunits of mitochondrial complex I, and TGF-β1. The expression of EMT-related factors and content of TGF-β1 was detected after carbonylcyanide-m-chlorophenylhydrazone(CCCP) treatment. Meanwhile, the migration potential of pancreatic cells was detected after small interfering RNA (siRNA) knockdown of the expression of TGF-β1.Results:After irradiation, the migration capacities of the cancer cells increased ( t=21.90, 35.64, P<0.05). The expression of N-cadherin ( t=4.42, 4.77, P<0.05), Vimentin ( t=4.57, 3.02, P<0.05), MMP2 ( t=7.27, 26.08, P<0.05), and MMP9 ( t=13.26, 7.29, P<0.05) all increased, while the expression of E-cadherin deceased ( t=8.37, 6.77, P<0.05). The expression of TGF-β1 ( t=90.49, 35.17, P<0.05) increased. The expression of TGF-β1 decreased with small interfering RNA, which paralleled the inhibition of the epithelial-mesenchymal transition and migration ( t=38.66, 11.54, P<0.05). Mitochondrial dysfunction was reflected by the decline in the membrane potential ( t=6.94, 29.71, P<0.05) and complex-related subunits. The expression of TGF-β1 ( t=47.93, P<0.05) and EMT-related factors further increased after mitochondrial function was destroyed ( t=16.51, P<0.05). Conclusions:Radiation-induced mitochondrial dysfunction can increase the expression of TGF-β1, which promotes epithelial-mesenchymal transition, and result in the migration of pancreatic cancer cell line.
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The incidence rate of biliary tract cancer is increasing year by year. Systemic therapy is the most important treatment for patients with advanced or unresectable biliary tract cancer. Gemcitabine combined with cisplatin is still the standard first-line chemotherapy, while gemcitabine combined with TS-1 and gemcitabine combined with nab-paclitaxel are also the first-line treatment options. Studies have confirmed that immunotherapy as a back-line treatment has a significant advantage in survival, and the disease control rate of nivolumab is 61% and the median overall survival is more than 1 year. In addition, targeted drugs targeting FGFR2, IDH1/2, HER-2 and other major driving genes of biliary tract cancer also show good antitumor activity, and become research hotspots in the treatment of advanced biliary tract cancer. Summarizing the research progress of systematic chemotherapy, immunotherapy and molecular targeted therapy for advanced biliary tract cancer can provide help for clinical practice.
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Objective:To investigate the mechanism underlying the inhibiting effect of low-glucose combined with palmitic acid on human colon cancer cells and its influence on the radiosensitivity.Methods:Under the treatment of low-glucose, palmitic acid and low-glucose combined with palmitic acid, the treatment condition that significantly inhibited the proliferation of SW480 was screened by CCK-8 assay. The reactive oxygen species (ROS) level, mitochondrial membrane potential and apoptosis rate were detected by flow cytometry. The changes in the radiosensitivity were detected by immunofluorescence-based γ-H 2AX quantification and colony formation assay. The protein expression level was detected by Western blot. Results:Compared with the control group, the condition of low-glucose combined with 120μmol/L palmitic acid significantly inhibited the proliferation of SW480 cells ( P<0.01). The expression levels of CPT1a, PFKFB3 and PKM were significantly up-regulated, the expression levels of NDUFV1, NDUFV2 and NDUFS1 were remarkably down-regulated, the ROS level was significantly increased and the ATP level was considerably reduced in the cells under metabolic stress (all P<0.01). After irradiation, the number of γ-H 2AX foci was significantly increased ( P<0.05), and the D 0 value was significantly reduced ( P<0.01), the ROS level was considerably increased ( P<0.001), the apoptosis rate was significantly increased ( P<0.001) and the expression level of γ-H 2AX protein was remarkably up-regulated ( P<0.01) in the low-glucose combined with 120μmol/L palmitic acid group. Pretreatment with NAC could reverse the changes of ROS, apoptosis and γ-H 2AX protein expression. Conclusions:The combination of low-glucose and palmitic acid can induce metabolic stress in SW480 cells, inhibit tumor proliferation and increase the radiosensitization when combined with radiotherapy by inducing the generation of ROS and DNA damage.
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Background:Malnutrition is common in patients with cancer, whichadversely affectsthesurvival and quality of life ofcancer patients.However, there is no national data on the prevalence of malnutrition inChinese cancer patients. Thisstudy aims to evaluate the prevalenceof malnutrition and quality of life(QOL)ofChinese patients with localregional, recurrentor metastatic cancer,to address the prognostic value of nutritional status and QOLon the survival of cancer patients in China and to validate the patient-generated subjective global assessment (PG-SGA) questionnaire in Chinese cancer patients.Methods:Thisisanobservational,multi-centered,and hospital-based prospective cohort study.We aimed to recruit 50,000 cancer patients (age 18and above)overan 8-year period.Data collection will occur within 48hrafter patientsare admitted to hospital, 30-days after hospital admission, and the follow-up will be conducted1-8years after enrolment. The primary outcomeisoverall survival, and secondaryoutcomes arelength of hospital stay and hospital costs. Factors measured are demographic characteristics, tumor characteristics, anthropometry measurements,hematological measurement, body composition, PG-SGAscores,Karnofsky performance status scores,and QLQ C30 scores. This protocol wasapproved by local ethical committees of all the participant hospitals.Conclusions: This multi-centered, large-scale, long-time follow-up prospective study will help diagnose malnutrition in cancer patients in China, and identify the related risk factors associated with the negative outcomes. The anticipated results will highlight the need for a truly scientific appraisal of nutrition therapy, and help to improve outcomes among cancer patients in China.Trial Registration: The trial has been registered with the Chinese Clinical Trial Registry, ChiCTR1800020329. Registered on 19 December 2018
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Objective:To investigate the expression of Pyruvate dehydrogenase kinase 1(PDK1), phosphorylated Pyruvate dehydrogenase (p-PDH) and Pyruvate kinase isozyme type M2 (PKM2) based on Warburg effect pathway in cervical cancer tissues, and explore the roles of these molecules on prognosis and recurrence after postoperative radiation.Methods:The expressions of PDK1, p-PDH and PKM2 in primary tissues of 102 patients with cervical cancer were detected by immunohistochemistry, including 63 patients receiving postoperative radiation. The expression of the three molecules on prognosis and the efficacy of postoperative radiation on cervical cancer were analyzed separately and corporately.The level of mRNA were verified by using the 300 patients from GEO database. Kaplan-Meier method and COX proportional hazards regression model were used for univariate and multivariate analysis.Results:High expression of PDK1 and all the three indicators (PDK1 high/p-PDH high/PKM2 high) were positively correlated with pelvic lymphnode metastasis ( χ2=10.890, 7.407, P<0.05). PDK1 high/p-PDH high/PKM2 high, Federation International of Gynecology and Obstetrics (FIGO) staging, pelvic lymph node metastasis and postoperative radiation could affect the overall survival (OS) and disease-free survival (DFS) ( P<0.05). Multivariate analysis showed that PDK1 high /PDH high/PKM2 high, FIGO staging and postoperative radiation were the independent prognosis factors for OS and DFS( P<0.05). The verification result of the GEO dataset showed that PDK1 high/PDH high/PKM2 high was the risk factor for DFS( P<0.05). Pathological type, pelvic lymph node metastasis and PDK1 high/p-PDH high/PKM2 high could affect the DFS of those patients with postoperative radiation ( P<0.05). In addition, the multivariate analysis showed that pathological type and PDK1 high /p-PDH high/PKM2 high were the independent prognosis factors for DFS( P<0.05). Conclusions:The patients of PDK1 high /p-PDH high/PKM2 high phenotype have poor prognosis and DFS with postoperative radiation, which may be a high-risk group with poor prognosis and high recurrence rate after postoperative radiotherapy of stageⅠ-Ⅱ B cervical cancer.This study provides a novel strategy for stratified treatment of cervical cancer.
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Objective@#To investigate the relationship between systemic inflammatory markers such as neutrophil/lymphocyte ratio (NLR) and C-reactive protein/albumin ratio (CAR), and lymph node metastasis in patients with cN0 gastric cancer. To establish a nomogram model to predict the risk of lymph node metastasis in patients with cN0 gastric cancer.@*Methods@#The preoperative systemic inflammatory markers and clinical data of 134 patients with cN0 gastric cancer were retrospectively analyzed, and these markers of patients with negative (pN0) or positive (pN+ ) lymph node metastasis in postoperative pathological diagnosis were compared. The receiver operating characteristic (ROC) curve was used to evaluate the predictive effect of preoperative systemic inflammatory markers on lymph node metastasis. The influencing factors for lymph node metastasis were assessed by univariate analysis and multivariate logistic regression analysis. A nomogram subsequently established by R software was validated by Bootstrap resampling as internal validation.@*Results@#Compared with pN0 group, NE (P=0.022), CRP (P<0.001), NLR (P<0.001), PLR (P=0.003) and CAR (P<0.001) were higher, LY (P=0.003) and Alb (P=0.042) were lower in pN+ group. ROC curve analysis showed that the area under the curve (AUC) of postoperative pathological lymph node metastasis in patients with cN0 gastric cancer diagnosed by NLR, PLR and CAR were 0.687, 0.651 and 0.694, respectively, and the best cutoff values were 2.12, 113.59 and 0.02, respectively. The corresponding sensitivity and specificity were 62.9% and 72.2%, 77.4% and 48.6%, 74.2% and 58.3%, respectively. Univariate analysis showed that tumor size, depth of invasion, NLR, PLR and CAR were associated with lymph node metastasis in cN0 gastric cancer patients (all P<0.05). Multivariate analysis showed that depth of invasion, NLR and CAR were independent influencing factors of lymph node metastasis in patients with cN0 gastric cancer. OR were 8.084, 3.540 and 3.092, respectively (all P<0.05). The C-index of the nomogram model was 0.847 (95% CI: 0.782-0.915). The predicting calibration curve was properly fit with the ideal curve in calibration chart.@*Conclusion@#Combination of NLR and CAR to establish a nomogram model has a good consistency and can accurately predict the risk of lymph node metastasis in patients with cN0 gastric cancer.
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Objective To analyze the clinical efficacy and prognosis of stereotactic body radiation therapy (SBRT) for pulmonary oligometastases.Methods Medical records of 104 patients with SBRT for pulmonary oligometastases in our hospital between 2012 and 2018 were retrospectively reviewed.SBRT was performed by intensity modulated radiation therapy (IMRT) technique before December 2015,and by helical tomotherapy (HT) technique in others.The local control (LC),progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method.Cox-regression was used for univariate analyses and multivariate analyses.The radiotherapy-related adverse events were evaluated by NCICTCAE V4.0.Results The 1-,2-and 3-year LC rates were 86.6％,75.9％ and 72.3％,respectively.The 1-,2-and 3-year PFS rates were 40.9％,28.4％ and 22.1％,respectively.The 1-,2-and 3-year OS rates were 75.9％,53.2％ and 43.53％,respectively.The median OS time was 26.6 months.Multivariate analyses showed that the pathologic type of primary tumor,the volume of lung oligometastases and the carcino-embryonic antigen (CEA) level before SBRT were the independent prognostic factors of LC (x2 =28.66,P＜0.05).The way of tumor progression after SBRT was the independent prognostic factor of OS (x2=40.01,P＜0.05).Meanwhile,there were no significant differences in the LC and OS between HTSBRT and IMRT-SBRT.Radiation pneumonitis was the major adverse event of SBRT (n =25,24.04％).Less than 7％ patients experienced grade 2 and above radiation pneumonitis.Conclusions SBRT shows high local control rates and tolerable adverse events in the treatment of pulmonary oligometastases.There were no significant differences in the clinical efficacy and adverse events between HT-SBRT and IMRT-SBRT,which means they are all suitable for clinical application.
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Objective To investigate the expression of microrchidia 2(MORC2) in glioblastoma patients and to evaluate its prognostic value of MORC2 expression combined with IDH1 mutation status for chemoradiotherapy efficacy and new molecular subtype.Methods The expression level of MORC2 in 45 glioblastoma tissues was measured by immunohistochemical staining and its correlation with clinicopathological characteristics and clinical prognosis after chemoradiotherapy was analyzed.Further more,the prognostic values of the expression of MORC2 combined with the status of IDH1 were assessed in a glioblastoma CGGA mRNA dataset.Results High expression of MORC2 was observed in 76％ of glioblastoma patients,which was negatively correlated with overall survival (HR=2.928,95％CI:1.582-5.418,P=0.002;recurrence-free survival (HR=2.204,95％CI:1.186-4.095,P=0.022).Moreover,according to the prognosis value of MORC2 expression and IDH1 mutation status,glioblastoma patients were divided into 3 molecular subtypes.Patients with the subtype of IDH1mt/MORC2low obtained the best clinical prognosis with a median survival of 22 months (95％CI:13.98-30.02),whereas those with the subtype of IDH1wt/MORC2high obtained the worst clinical prognosis with a median survival of 5.63 months (95％CI:3.92-7.34,HR=4.15,95％CI:3.92-7.34,P=0.002).Among IDH1wt glioblastoma patients,MORC2high patients had worse clinical prognosis compared with MORC2low counterparts,prompting that IDH1wt/ MORC2high glioblastoma tissues yielded higher capability of DNA injury repairing and resistance to chemoradiotherapy.Conclusions The high expression of MORC2 can be used as a potential indicator of poor prognosis of glioblastoma patients after chemoradiotherapy.IDH 1 mutation status combined with MORC2 expression can establish a novel molecular subtyping,which provide evidence for stratified therapy for glioblastoma patients.
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Rectal cancer is one of the most common malignant tumor in our country,among them with highest incidence of low rectal cancer.With the further study on the biological behavior of rectal cancer and the development of diagnostic and therapeutic techniques,gastrointestinal oncologists have proposed a new treatment strategy-local resection and wait-and-see.This strategy can better preserve anal function and improve the quality of life of patients without losing the good tumor control of the traditional standard treatment model.
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Objective The objective of this study was to provide a way to assess the nutritional status of patients and to afford targeted nutritional supports during the radiotherapy on the basis of the laboratory parameters related to nutrition and chest muscle size in lung cancer patients at the different time.Methods The laboratory parameters were obtained in a cohort of 160 lung cancer patients who received thoracic radiotherapy in our department from March 2012 to November 2015.Fourteen patients who had complete chest CT scan images during radiotherapy were selected to evaluate chest muscles volume.The Chest muscles and its volume were delineated and calculated by CT scan images.Results The levels of(Hemoglobin)HGB,lymphocyte,total protein and albumin were decreased in different degrees during and after radiotherapy,which had the positive correlation with the number and doses of radiotherapy(P0.05).Conclusion Cancer patients were prone to suffer from malnutrition during radiotherapy.The intake of energy and protein was less than the requirements.We should always take the nutritional status of patients into account and provide targeted nutritional support to improve treatment tolerance and quality of life of patients during radiotherapy.
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Objective To evaluate the clinical efficacy and prognostic factors of stereotactic body radiotherapy(SBRT)for pulmonary oligometastases,and to further explore the patients most suitable for SBRT. Methods From 2012 to 2105,51 patients with 76 oligometastatic lung tumors were treated with SBRT.In those patients,27 had primary lung tumors and the others had extrapulmonary tumors. Seven patients had squamous cell carcinoma,thirty-five had adenocarcinoma, and the rest had other types of cancer. The patients received radiotherapy at a dose of 50 Gy in five fractions or 60 Gy in three fractions. Survival analysis was made by the Kaplan-Meier method. A multivariate analysis was made by the Cox model. Results The 1-and 2-year local control rates were 86%(65/76)and 80%(61/76),respectively. The 1-and 2-year overall survival(OS)rates were 80%(41/51)and 55%(28/51),respectively. The median survival time was 30(2-57)months,while the median progression-free survival time was 8(1-32)months. Twenty-one patients had grade 1 radiation pneumonitis(RP),while one patient had grade 2 RP. The multivariate analysis revealed that no more than 2 oligometastatic lung tumors,progression-free interval(PFI), and a performance score(PS)no higher than 1 were independent factors for OS(all P<0.05). Conclusions SBRT is effective and safe for treating pulmonary oligometastases. The number of oligometastatic lung tumors,PFI,and PS are independent prognostic factors for OS. Suitable patients and the appropriate timing of treatment are key to the efficacy of SBRT.
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Objective To divide computed tomography (CT) values into different ranges and investigate the influence of CT value division on dose calculation, and to propose a method to combine magnetic resonance imaging (MRI) with assigned CT values.Methods Ten CT images each were collected from patients with head and neck, chest, and pelvic tumors.Random sampling was performed for the CT values of main tissues or organs at the three parts, and then the mean CT value of each tissue or organ was calculated to divide the CT values into different ranges.A virtual phantom was built in the Varian Eclipse treatment planning system, and for the prescribed dose of 100 cGy, the machine output was recorded at different CT values.The influence of different CT value ranges on dose calculation was analyzed.The treatment plans of intensity-modulated radiotherapy were selected from 5 cervical cancer patients, and new CT values were assigned to the planning target volume (PTV) and organs at risk to obtain new CT images.The plans were transferred to the new CT images and compared with the results on the original CT images in terms of dosimetric parameters.Results After dividing the CT values into different ranges and verifying the results in dose calculation, the CT values corresponding to different human tissues or organs were-100 to 100 HU.The influence of CT value variation on dose calculation was within 3%.In the same treatment plan, there were small differences in dosimetric parameters between new CT images and original CT images.Dmax, Dmean, D98%, D95%, D5%, and D2% of PTV were all below 3%, and Dmax and Dmean of the bladder, rectum, small intestine, femoral head, and bone marrow were below 2%.Conclusions The influence of CT value division on dose calculation in the treatment planning for pelvic tumors is acceptable, so it can be used in combination with MRI.
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Objective To investigate the effect ot ionizing radiation (IR) on the expressions of HMGB1 in the radiation-sensitive and radiation-resistant human cervical cancer cells and to analysis the role of HMGB1 in the regulation of radiosensitivity.Methods Human cervical cancer cells HeLa and its radioresistant strain HeLaR cells were irradiated with different doses of X-rays.The cells were collected at different time points after irradiation.The expressions of protein and mRNA of HMGB1 were detected by Western blot and real-time quantitative PCR.Results At the protein level,the expression of HMGB1 in HeLaR cells was significantly reduced at 6-36 h after 2,5 and 10 Gy X-ray irradiation (t =3.574-9.754,P ＜0.05),and then it was recovered to the control level at 48 h after IR.On the contrary,the expression of HMGB1 in HeLa cells was significantly increased at 6,12,48 h after 2 Gy IR (t =3.945-4.864,P＜0.05),at 6,36,48hafter5 GyIR (t=-2.875-3.295,P＜0.05),and at 36,48 h after 10 Gy IR (t =-4.480,-4.517,P ＜ 0.05).At mRNA level,the trend of HMGB1 expression alteration was consistent with that of protein expression.Conclusions The changes of HMGB1 expression can be differently induced by X-rays in the human cervical cancer radiation-sensitivity cells and radiation-resistant cells.HMGB1 may be involved in the radioresistance of human cervical cancer.
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Mitochondrial DNA (mtDNA) is more susceptible to oxidative damage and has a higher mutation rate compared with nuclear DNA due to the absence of protective histone proteins and imperfect repair system.Somatic alterations in mtDNA have been proposed to contribute to initiation and progression of human cancer in previous researches.However,the role of these mtDNA alterations in gastric cancer progression remains unclear.Point mutations and mtDNA content alterations are the two most common mtDNA alterations that result in mitochondrial dysfunction in gastric cancers.Identifing somatic mtDNA alterations in gastric cancers as well as their association with the clinicopathological parameters of gastric cancer,and exploring the causative factors of the somatic mtDNA alterations in cancer progression have been a new direction of gastric cancer research in recent years.
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Objective To investigate the radiosensitization effects of the combination treatment of clioquinol (CQ) and zinc on human cervical cell line HeLa in vitro.Methods Cells were divided into the 4 groups:controls,drug,radiation,and combined drug and radiation group.Cytotoxic effect of CQ and zinc on cell viability was determined by CCK-8 assay.Radiosensitization effect of CQ and zinc on HeLa cells was detected by colongenic assay,and the single-hit multi-target model was used to stimulate the doseresponse curve of survival and to calculate radiosensitization parameters.The cell cycle and apoptosis of HeLa cells were analyzed with flow cytometry.Luciferase reporter assay was used to study NF-κB activity of HeLa cells.Results The combination of CQ and zinc inhibited cell growth in a dose-dependent manner (F =188.00,P ＜ 0.01).The mean lethal dose was 3.16 and 2.04 Gy for radiation group and combined drug and radiation group,respectively,and hence the SER was 1.55.Compared with the radiation group,the ratio of G2-phase cells in the combined drug and radiation group decreased(t =10.39,P ＜ 0.05),the apoptosis rate increased at 24 h post-irradiation (t =5.64,P ＜ 0.01),and the NF-κB activity decreased (t =21.42,P ＜ 0.05).Compared to the control group,the NF-κB activity increased in the radiation group(t=6.23,P＜0.05),but decreased in the drug group(t =12.48,P＜0.05).Conclusions The combination of CQ and zinc could increase the radiosensitivity of HeLa cells by decreasing the ratio of G2-phase cells,increasing apoptosis and the inhibiting of NF-κB activity.
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Ubiquitin-proteasome pathway is one of the primary pathway in intracellular protein degrada-tion,therefore the ubiquitin conjugating enzyme D3(UbE2D3)which involved in the ubiquitin mineralization process can affect the biological effects accordingly to affect some protein and nucleic acid content and activity. The function that participate in modification and degradation of some cancer factors is vital in tumor cells,and followed by tumor biological behavior changing. Researches show that UbE2D3 correlates with human telomer-ase reverse transcriptase( hTERT),radiation sensitivity,aggressive,etc in breast cancer.
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As one of the treatment options for early stage NSCLC,stereotactic body radiation therapy (SBRT)is mainly applied to the inoperable patients.Compared with small doses of traditional fractionated radi-ation treatment,SBRT are taken a single high dose of radiation.A large body of experience has been accumula-ted over the years and the mathematical model to describe survival in high dose range typically used in SBRT and the best dose of segmentation model were focused on,but there has not yet reached a consensus.Studies show that SBRT has certain advantages in local control ratio and adverse reaction compared with traditional radiotherapy,which can be used in operable patients in the future.
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Objective To explore the feasibility of using the modified continuous balloon dilatation substituting the traditional membrane-covered stent in the treatment of benign esophageal stenosis in children.Methods A retrospective analysis of the clinical data of 25 cases with esophageal stenosis from January,2012 to February,2014 was conducted.Preoperative esophageal stenosis was confirmed by angiography,and the expansion of the stenosis segment was examined after 2-4 weeks postoperatively.According to the age and the location of the esophageal stricture,25 cases were classified into two groups.Twelve cases of group A without obvious contraindications were treated by continuous balloon dilatation,while 13 cases of group B with age of less than 3 years or upper esophageal stenosis,retrievable stent implantation was performed.All cases were followed up from 6 months to 2 years.Clinical symptoms,swallowing fluency and the degree of esophageal stricture were followed up at 1,3,and 6 months postoperatively,and the effect of treatment was evaluated.Results Two groups of patients were successfully treated,and the stents were removed successfully after 2-4 weeks.The average diameter of the stenosiswas significantly increased after treatment,swallowing was improved obviously,with no perforation,hematemesis and melena and other serious complications.The balloon moved down happened in one case,which was adjusted under perspective observation.One case in group A underwent colonic interposition for esophageal replacement because of recurrence of restenosis.The balloon dilatation was effective in 10 cases.In Group B,5 patients had stent migration or displacement,3 cases had recurrent esophageal stricture,and the treatment was effective in 5 cases.There was significant difference in complications between the group A and B (x2=5.23,P＜0.05).Conelusions Continuous balloon dilatation is a simple,effective procedure with fewer complications in the treatment of children with benign esophageal stenosis.In addition to stenting,it may be another ideal choice for benign esophageal stenosis in children.
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Triple negative breast cancer (TNBC) is a special subgroup of breast cancer with more aggressive biological behavior and clinicopathological characteristics,and the therapy of TNBC has always been the research difficulty and hot spot.Currently,surgery and adjuvant radiotherapy are still the main method in local treatment,amd the research of traditional chemotherapy and targeted therapy have been made some progress.Meanwhile,new drugs continuously appear in recent years.
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Objective To establish the mitochondrial DNA depleted cell line (ρ0 cells) of lung cancer cell A549 and to observe the radiosensitivity difference between ρ0 cells and normal A549 cells (ρ + cells).Methods The ρ0 cells were depleted of mitochondrial DNA by culturing chronically in the presence of low concentration of ethidium bromide (EB),and then the cell model was confined.Radiosensitivity of both ρ0 cells and ρ + cells was detected using the cologenic formation assay.After 6 MV X-ray irradiation in vitro,cell cycle distribution and reactive oxygen species (ROS) level were analyzed by flow cytometry and fluorescence microplate reader,respectively.Results A ρ0 cell line was successfully established and had a lower radiosensitivity than ρ + cells (t =12.57,P ＜ 0.01).After irradiation with a dose of 8 Gy,compared to ρ+ cells,ρ0 cells showed prolonged G2 arrest with less cells in G2 (t =6.82,P ＜ 0.01) and had lower increase of ROS level (t =14.51,P ＜ 0.01).Conclusions ρ0 cells have a lower radiosensitivity than ρ + cells,in which the reduction of ROS production and the prolongation of G2 arrest post-irradiation may be involved.