Objective To investigate the combination effect of cetuximab and irradiation on colorectal carcinoma CL187 cell line and underlying molecular mechanism.Methods CL187 cells with or without cetuximab treatment were irradiated by 0,4 and 8 Gy X-rays,then cell death percentage was determined by MTT 24 and 48 h post-irradiation.Clone forming assay was used to evaluate the cell reproliferation ability.Cell cycle distribution,apoptosis,and necrosis were analyzed by flow cytometry.Western blot was used to detect the protein expressions of DNA-PKcs,Ku70 and Ku80.Results The cetuximab enhanced the percentage of radiation-induced cell death,while descreased the cloning formation capacity and increased radiosenvtivity (t =-6.14、-6.53,P ＜0.05).The SER of cetuximab on CL187 cell line approached to 1.38.In addition,cetuximab also increased radiation-induced G0/G1 phase arrest (t=-4.64,P＜0.05) and the percentage of apoptosis and necrosis (t=-9.16,P ＜0.05),but it descreased the expression levels of DNA-PKcs,Ku70 and Ku80 proteins.Conclusions The cetuximab treatment might enhance the inhibitory effect of irradiation on colorectal carcinoma CL187 cell line by influencing cell cycle distribution,cell apoptosis,and the expression of DNA repair proteins.

Objective To investigate the effect and underlying mechanism of single,fractioned and continuous low dose rate radiation on CL187 colorectal cancer cell line.Methods CL187 cells were exposed to 6 MV X-rays at a high dose rate of 4 Gy/min and 125Ⅰ seed at a low dose rate of 2.77 cGy/h with three groups:single dose radiation group (SDR),fractioned dose radiation group (FDR) by 2 Gy/f,and continuous low dose rate radiation group (CLDR).The radiation doses were 0,2,4 and 8 Gy.Total cell number and cell viability were determined by trypan blue.Clone forming assay was used to evaluate the cell proliferation ability.The percentage of apoptosis cells was analyzed by flow cytometry.Western blot was used to detect the protein expression levels of PHLPP2,PTEN and Bax.Results Compared with SDR and FDR groups,the total cell number and survival fraction of CLDR group decreased.The relative biological effect (RBE) for 125Ⅰ seeds compared with 6 MV X-rays was 1.41.The percentage of apoptosis cells of CLDR group was significantly increased (t =-15.08,-11.99,P ＜ 0.05).The expression level of Bax increased in CLDR group,while no obvious changes were observed on PHLPP2 and PTEN among three groups.Conclusions The expression level of PHLPP2 increaseS in SDR,FDR and CLDR group,while it seems that it was not influenced by dose rate.The expression level of Bax increased in three groups,while more colorectal CL187 cells in CLDR group may be killed due to the increase of Bax expression.

Objective To investigate the effect of C225 on DNA repair and molecular pathways in CL187 colorectal cancer cells after irradiated by 125Ⅰ radioactive seeds.Methods In the experiment involved were four groups:control group,100 nmol/L C225 treatment group,125Ⅰ radioactive seeds continuous low-dose rate irradiation group and C225 combined with 125Ⅰ radioactive seeds continuous lowdose rate irradiation group.Cells were collected at 48 h after 4 Gy irradiation,and γH2AX foci/cell and γH2AX foci positive cells were counted with immunofluorescence.At the same time,DNA repair proteins were detected by Western blot.Cells were lyzed immediately after 4 Gy irradiation,and changs in EGFR downstream signaling molecules were detected by Western blot.Results Compared with 125Ⅰ seeds irradiated cells,cells treated with C225 and 125Ⅰ seeds irradiation showed more γH2AX foci per cell (t =8.0,P =0.05),and more γH2AX foci positive cells (t =6.8,P ＜ 0.05) and less expression of Ku70 (t =6.6,P ＜ 0.05) and DNA-PKcs (t =5.6,P ＜ 0.05).Combined with 125Ⅰ-CLDR irradiation,C225 reduced cellular EGFR level(t =4.9,P ＜0.05) and inhibited the activation of Akt(t =5.5,P ＜0.05).Conclusions In the condition of 125Ⅰ seeds irradiation,C225 reduced the expression of Ku70 and DNA-PKcs,inhibited the activation of Akt and attenuated the DNA damage repair capacity in CL187 colorectal cancer cells.

Objective To summarize the efficacy and the feasibility of 125I seed implantation for recurrence cervical lymph node of head and neck tumor after radiotherapy or radiotherapy plus neck dissection. Methods Thirty-six patients with the recurrence cervical lymphnode of head and neck tumor after radiotherapy (17 patients) or radiotherapy plus neck dissection (19 patients) were treated with 125I seed implantation guided by ultrasound or CT under local anesthesia. The median number of seeds was 27( range from 3 to 78 ). Postoperative quality evaluation were routinely obtained for all patients. The actuarial D90 ranged from 90-160 Gy (median, 130 Gy). Results The follow-up rate was 100%. The number of the patients who were followed up over 1-and 2-year were 11 and 3. The overall response rate was 81%. The 1-and 2-year over local control rates, over survival rates were 69% and 35%, 50% and 22%, respectively.The 1-and 2-year local control rates in patients with recurrence node after radiotherapy plus neck dissection were 72% and 54%, while those were 67% and 50% in patients with recurrence node after radiotherapy,respectively (χ2=00,P=0.965). The 1-and 2-year survival rates in two groups were 48%, 13% , and 51%, 39%, respectively (χ2=0.17, P=0.676). Conclusions 125I seed implantation is a safe,minimal invasive with low morbidity and high efficacy salvage treatment method for cervical lymph node recurrence of head and neck tumor after radiotherapy with or without neck dissection.

Objective To investigate the inhibition effect of continuous low dose rate radiation by 125Ⅰ radioactive seeds on Hep-2 cells and the corresponding mechanisms.Methods Hep-2 cells were divided into three groups,control group,single dose radiation group with high dose rate form X-rays (SDR) and continuous low dose rate radiation by 125Ⅰ seeds group (125Ⅰ-CLDR).After exposure to SDR and 125Ⅰ-CLDR,colony formation assay was used to determine the radiosensitivity and RBE,trypan blue exclusion assay was used to determine cell proliferation,and flow cytometry was used to detect cell apoptosis and cell cycle arrest.Results The radiosensitivity of Hep-2 cells to 125Ⅰ-CLDR was higher than that to SDR.The RBE of 125Ⅰ-CLDR versus SDR was approximately 1.61.The α/β ratio of 125Ⅰ-CLDR group was higher than that of SDR group.Both SDR and 125Ⅰ-CLDR inhibited cell proliferation (t =30.9,40.7,P＜0.05),in which 125Ⅰ-CLDR was stronger than SDR (t =9.8,P＜0.05).In addition,the incidences of apoptosis and G2/M arrest induced by125Ⅰ-CLDR were also stronger than those induced by SDR (t =5.8,19.8,P ＜ 0.05).Conclusions 125Ⅰ-CLDR generates more serious inhibition effects than SDR on reducing cellular DNA repair capacity,inducing cell apoptosis and G2/M arrest and inhibiting proliferation of Hep-2 cells.

Background Studies have determined that nucleotide binding oligomerization domain 2 (NOD2) plays a key role in innate immune response.However,whether NOD2 participates in the nature defense of fungal keratitis is unclear.Objective This study was to investigate the expression and significance of NOD2 on cornea in the initial of Aspergillus fumigatus keratitis (AFK) in rats.Methods Seventy-two adult clean Wistar rats were randomized into the normal control group,only corneal epithelial scraped group and AFK model group,and the AFK models were established by incubating Aspergillus fumigatus to cornea after corneal epithelium was scraped.All the operations were performed in the right eyes of rats.Reverse transcription PCR (RT-PCR) was carried out to detect the expression of NOD2 mRNA in corneal epithelium 4,8,16,24 hours after operation.Twenty-four hours after operation,the expression of NOD2 protein in rat corneas was examined by immunochemistry and immnunofluorescence technology.Also,the rat corneas were obtained for regular histopathological examination.The use and care of the animals complied with Institutional Animal Care and Use Committee Guidebook by NIH.Results All the models were made successfully.RT-PCR revealed that a fewer NOD2 mRNA were expressed on cornea in the normal control group,but the expressing levels of NOD2 mRNA were increased in the only corneal epithelial scraped group and AFK model group.Compared with only corneal epithelial scraped group,the elevated values of NOD2 mRNA expression in the AFK model group were statistically significant at 4,8,16 and 24 hours after operation (t =-0.409,-0.439,-0.534,-0.618,all at P=0.000).The histopathological examination displayed that the cornel tissue had intact structure in the normal control group,and partly corneal epithelial deficiency,slight corneal swelling and fewer neutrophil granulocytes were seen in the only corneal epithelial scraped group.However,corneal ulcer,severe corneal edema and a lot of neutrophil granulocytes were exhibited in the AFK model group.Immunochemistry and immnunofluorescence staining evidenced that weaker expression of NOD2 was visualized in the corneal epithelial and endothelial layers,and obviously enhanced staining was seen in the AFK model group.The expressing levels (absorbancy) were 0.045 ± 0.005,0.050 ± 0.005 and 0.092 ± 0.006 in the normal control group,only corneal epithelial scraped group and AFK model group,respectively,showing a significant increase in the AFK model group compared with the only corneal epithelial scraped group (t =0.042,P =0.000).Conclusions Expression of NOD2 is upregulated in the corneas with AFK,suggesting that NOD2 participates the natural defense in the initial of fungal keratitis.NOD2 may play an important role in the process of anti-fungal innate immune response in cornea.

Objective To investigate the effect of cetuximab (C225) on the radiosensitivity of colorectal cancer cells CL187 and underlying mechanism.Methods Cell survival was detected by colony forming assay.The levels of apoptosis and cell cycle distribution were determined by flow cytometer.The mitotic ratio was measured by Wright' s-Giemsa mixed coloring method.The protein levels of Bax and Bcl2 were detected by Western blot.Results The sensitizing enhancement ratio of C225 was approximately 1.4.C225 treatment and 125I seed radiation induced G1 cell cycle arrest individually.C225 increased the radiation-induced apoptosis (t =6.6,P ＜ 0.05) and cellular Bax/Bcl-2 ratio (t =9.4,P ＜ 0.05),but did not increase radiation-induced G1 arrest.In addition,there was no difference in mitotic index among different groups.Conclusions C225 sensitizes CL187 to 125I seed irradiation,which might be related with increase of radiation-induced apoptosis.

Objective To determine the maximum tolerated dose ( MTD) and dose?limiting toxicity ( DLT) of weekly PTX and DDP concurrent postoperative radiotherapy in Chinese women with high?and intermediate?risk early cervical cancer. Methods Women with high risks postoperative cervical carcinoma, ECOG≤2 were eligible. Pelvis RT (6/10 MV X?ray,3DCRT 40 Gy/20f,para?metrial boost 10?20 Gy/5?10f) was followed by 2?4f brachytherapy applications ( 192 Ir,5 Gy/f) . Concurrent weekly chemotherapy was started at DDP 20 mg/m2 and PTX 10 mg/m2 weekly,and escalated in three?patient cohorts according to 3+3 methods. Results 25 patients were enrolled and treated over seven doses levels until dose?limiting toxicity (DLT) was reached. Median age was 48 years (range,34?66).All of patients finished RT in 7 weeks. Grade 3,4 non?hematologic toxicities were diarrhea and observed in two patients (4 cycles,DLT) at level 7.Grade 3,4 hematologic,principally leukopenia and neutropenia,and occurs late cycles. One grade 4 leukopenia and neutropenia was observed at dose level 6 but not seen in three additional patients. No one was delayed treatment time by concurrent chemotherapy.22 patients finished 6 cycles. Median follow?up is 59. 5 months. Three patients have died of cancer metastasis and recurrence. One patient has died of respiratory failure. Conclusions Combination PTX and DDP administered concurrently with pelvic EBRT can be safely administered at the MTD of DDP 35 mg/m2 and PTX 30 mg/m2 weekly for six cycles in Chinese women with postoperative cervical cancer.

Background The rapid diagnosis can win more treating opportunities for patients with fungal keratitis.Even though the fungal culture is the gold standard for the diagnosis of fungal keratitis,it is difficult in early diagnosis due to the long duration of cultivation and false-negative rate.Objective This trial was to explore the clinical value in the rapid diagnosis of fungal keratitis by the combination of corneal scraping with laser scanning confocal microscopy.Methods Corneal scraping and laser scanning confocal microscopy were separately performed in 167 eyes of 167 patients with fungal keratitis.All the eyes were examined by the slit lamp,followed by laser scanning confocal microscope,and then the 10％ KOH corneal smear was examined under the optical microscope.Results The positive rate of diagnosis was 75％ (125/167) by corneal scraping,and that by laser scanning confocal microscopy was 91％ (152/167).The positive rate of examining outcome was significantly higher in laser scanning confocal microscopy than that of corneal scraping (x2 =14.88,P =0.00).The positive results were 114 cases and negative results were 4 cases by two methods,with the concordance rate 70.7％ (118/167).The hyphae or spore were seen in 32 cases by laser scanning confocal microscopy in 42 negative cases by corneal scraping,and in 15 negative cases by confocal laser scanning microscopy,11 positive outcomes were offered by corneal scraping.Conclusions The combined application of corneal scraping with confocal laser scanning microscopy can improve and speed up the diagnosis positive rate of fungal keratitis.

Objective:To investigate the accuracy and feasibility of 3D-printing individualized template-guided and CT-guided 192Ir interstitial brachytherapy in the central recurrent gynecologic tumors by comparing pre-plan and intraoperative physical dosimetric parameters. Methods:This study involved 38 patients with central recurrent gynecologic tumors who underwent 3D printing individual template (3D-PIT)-assisted and CT-guided 192Ir interstitial brachytherapy in the Department of Radiation Oncology of the Peking University Third Hospital from Jan 2018 to Dec 2019.The prescription doses for the target tumor areas were 10-36 Gy to be delivered at 5-6 Gy/fraction for 2-6 fractions.The pre-plan and intraoperative dosimetric parameters were compared, including the minimum prescription doses delivered to 90% and 100% of target volume( D90, D100)and the mean percentage of volume receiving 100% of the prescription doses ( V100). Meanwhile, the doses delivered to 2 cm 3 ( D2 cm 3) of organs at risk (bladders, rectums, and colons) were analyzed.The quality parameters of the brachytherapy were studied, including conformity index (CI), homogeneity index (HI), and external index (EI) of the target volume.Perioperative complications were also observed. Results:A total of 194 treatments were included.During the treatment, 5-13 (median 6) needles were inserted, with a prescription dose of 5-6 Gy per fraction.There were no statistical differences between pre-plan and intraoperative D90, D100, V100, CI, HI, and EI as well as the D2 cm 3 of bladders and colons at risk ( P>0.05). In contrast, for the D2 cm 3 of rectums, the intraoperative dose was slightly higher than the pre-plan dose, showing a statistical difference ( t=-0.335, P=0.027). Conclusions:The 3D-PIT-assisted and CT-guided 192Ir interstitial brachytherapy at a high dose rate is accurate and feasible in the treatment of recurrent gynecologic tumors, meeting the pre-plan dose requirement.