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Radiation-induced brain injury is a neurological injury caused by radiation therapy of head and neck tumors. The pathogenesis is still unclear. It is hypothesized that immune cells play an important role in radiation-induced brain injury. The excessive activation of microglia in the central nervous system and the migration of peripheral immune cells into the brain collectively promote the incidence and development of radiation-induced brain injury. In this article, the immunological mechanism underlying the radiation-induced brain injury was reviewed.
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Objective To evaluate dose variations induced by gravity of multi-leaf collimator to provide references for clinical intensity-modulated radiotherapy.Methods Two-dimensional dose distributions in the central plane of IMRT fields were measured by use of a 2D ion chamber array.All measurements were repeated at two collimator angles (C=0 and 90°),for each of the following gantry angles:G=0 and 270°.Comparisons were made to dose distributions generated at G=0°and their differences were analyzed using gamma index analysis (3％/3 mm and 1％/1 mm).Results Under the radiation field of 10 cm×10 cm,the gamma passing rate was higher than 99％ for 3％ 3 mm anch close to 95％ for 1％/1mm Under a 3％/3mm error standard,the average matching rate for step & shoot fields was (96.46±0.33)％ and for DMLC fields was (94.67±0.54)％ at C=0°;The average matching rate for step & shoot fields was (94.59±0.47)％ and for DMLC fields was (92.60±0.52)％ at C=90°.Under a 1％/1mm error standard,the average matching rate for step & shoot fields was (89.83 ±1.06)％ and for DMLC fields was (85.84±0.57)％ at C=0°;The average matching rate for step & shoot fields was (86.91 ±1.71)％ and for DMLC fields was (83.89±0.69)％ at C=90°.Concusion MLC weight effect affects IMRT delivery dose,and DMLC fields are more sensitive to gravity than step & shoot fields.
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Objective To explore the value of an innovative teaching model which combined problem based learning (PBL) method with case based learning (CBL) method in clinical oncology Teaching.Methods 68 students were divided into the combinational teaching group (30 cases) and the LBL group (38 cases).The combinational teaching group was taught by PBL method combined with CBL method, and this dual track teaching was based on cases and problems.The traditional teaching group was taught by LBL method.The teaching effect was evaluated by students' questionnaire survey and test score.SPSS 13.0 was used to two groups to do t test for statistical analysis in test score and x2 test for degree of satisfaction.Results In the final examination, the score of non-case test of combinational teaching group was similar to that of traditional teaching group (50.30 ± 7.19 vs.52.04 ± 8.01, P=0.358).The combinational teaching group had significant improvement in case analysis test (35.76 ± 5.28 vs.31.80 ± 5.16), and the difference was statistically significant (P=-0.003).In the course of teaching satisfaction survey, the dual track teaching group, compared with the conventional teaching group, has a better effect on self study ability, communication skills, communication skills, and higher satisfaction for teaching, and more willing to continue to carry out teaching (P＜0.05).Conclusion The PBL+CBL combinational teaching model can make a great contribution to improving the teaching quality and satisfaction, and worthy of being popularized and applied.
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The inhibitory effects of Endostar in combination with radiotherapy in BALB/c nude mice model of human CNE2 nasopharyngeal carcinoma and the mechanism were investigated. In nude mice model of CNE2 nasopharyngeal carcinoma, the inhibitory rate and the sensitizing enhancement ratio (E/O) were calculated according to the tumor volumes in different groups. The expression of microvascular density (MVD) in tumor tissues was examined by using immunohistochemistry staining. The transcription of VEGF gene was detected by using RT-PCR. The inhibitory rate in Endostar+ radiotherapy group was higher than in other groups. In Endostar+radiotherapy group, the tumor volume was significantly decreased and the E/O ratio was 2.335, suggesting that Endostar could be a radiosensitizer. The expression of MVD of tumor tissues in Endostar+radiotherapy group was reduced significantly. The expression of the MVD in treatment groups was significantly different from that in control group (P<0.05). Compared to other groups, VEGF mRNA expression in Endostar+radiotherapy group was decreased remarkably. Endostar in combination with radiotherapy significantly inhibited the growth of CNE2 tumor. The combination therapy decreased the expression of VEGF, and inhibited tumor angiogenesis and proliferation. When combined with radiotherapy, Endostar acted as a radiosensitizer.
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The benefit achieved by concurrent chemoradiotherapy (CCR) and sequential chemoradiotherapy (SCR) vs radiotherapy (RT) alone for patients with stage II-IVa nasopharyngeal carcinoma (NPC) was compared. A total of 113 patients with stage II-IV a NPC were allotted into CCR group (n=38), SCR group (n=36) and RT alone group (n=39). All patients were irradiated with the same RT technique to ≥66 Gy at 2 Gy per fraction, conventional 5 fractions/week in all groups. The CCR group received concurrent chemotherapy of weekly cisplatin for 7 weeks, and the SCR group received neoadjuvant and (or) adjuvant chemotherapy. The results showed that the 3- and 5-year overall survival rate was significantly higher in CCR group than in RT alone group (92.16% vs 61.54%, 81.58% vs 51.28%, P<0.005). The median survival time was significantly longer in CCR group than in RT alone group (67.8 months vs 52.7 months, P<0.005). It was concluded that CCR could significantly improve overall survival rate, progression-free survival rate, and median survival time when compared with RT alone.
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The chronic-hypoxia-resistant gastric cancer cell line was established, and its biological characteristics were explored and compared with the parental cell line. Gastric cancer cell lines were cultured under the degressive oxygen concentration. Cell doubling time was calculated by cell counting method. Chemo-resistance ability of cells was tested by MTT assay. Irradiation tolerance of cells was evaluated by colony forming method. Cell cycle distribution was tested with flow cytometry. Invasive ability was tested by Transwell method. The expression levels of GLUT-1 and HIF-1α were detected by using Western blot. MNK45/HYP cells successfully survived under the 1% concentration of oxygen and its cell doubling time was 35.01±1.02 h, while that of MNK45 was 27.35±0.83 h (P<0.01). The percentage of MNK45/HYP cells in G(0)/G(1) stage was (58.3±6.1)%, and that of MNK45 cells was (42.2±6.0)% (P<0.05). Comparing with the parental cells MNK45, drug resistance indexes of 5-Fu, PTX, OXA, Sn38, GEM and VP16 in MNK45/HYP cells were respectively 5.3, 1.3, 3.6, 2.2, 4.8 and 4.4. Colony forming ability of MNK45/HYP cells after irradiation was also significantly higher than MNK45 cells. The invasive number of MNK45/HYP cells was 107.7±17.5, while that of MNK45 cells was 59.0±9.9. The expression levels of GLUT-1 and HIF-1α in MNK45/HYP cells were significantly higher than those in MNK45 cells. MNK45/HYP cells hold biological characteristics of hypoxia tumor with good tolerance to chronic hypoxia, and can be used for the research of solid tumor under chronic hypoxia condition.
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In order to investigate the effects of short hairpin RNA (shRNA) on the expression of Survivin, cell cycle and cell proliferation in MCF-7 cells, using a pEGFP vector which contained a U6 promoter shRNA plasmid targeted against survivin was constructed and transfected into MCF-7 cells. The change of the expression of Survivin and cell proliferation rates were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and MTT methods respectively. The change of cell cycle after transfection was analyzed by flow cytometry. The results indicated that the recombinant plasmid containing Survivin shRNA was constructed successfully, which could suppress the expression of Survivin at mRNA and protein level. The growth of MCF-7 cells was arrested in G1 phase of the cell cycle and the proliferation activity was suppressed after transfection. It was concluded that Survivin shRNA plasmid could knock down the expression of Survivin in MCF-7 cells specifically. In addition, Survivin shRNA plasmid could lead to G1 arrest and inhibit the proliferation of MCF-7 cells, which suggested that Survivin shRNA might be used as a new therapeutic method for breast cancer.
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In order to investigate the effects of short hairpin RNA (shRNA) on the expression of Survivin, cell cycle and cell proliferation in MCF-7 cells, using a pEGFP vector which contained a U6 promoter shRNA plasmid targeted against survivin was constructed and transfected into MCF-7 cells. The change of the expression of Survivin and cell proliferation rates were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and MTT methods respectively. The change of cell cycle after transfection was analyzed by flow cytometry. The results indicated that the recombinant plasmid containing Survivin shRNA was constructed successfully, which could suppress the expression of Survivin at mRNA and protein level. The growth of MCF-7 cells was arrested in G1 phase of the cell cycle and the proliferation activity was suppressed after transfection. It was concluded that Survivin shRNA plasmid could knock down the expression of Survivin in MCF-7 cells specifically. In addition, Survivin shRNA plasmid could lead to G1 arrest and inhibit the proliferation of MCF-7 cells, which suggested that Survivin shRNA might be used as a new therapeutic method for breast cancer.