Objective To explore the imaging diagnostic value of gastrointestinal stromal tumor(GIST).Methods The retrospective study on GIST proved by operation and pathology in 11 cases was done.There were pneumobarium double contrast examination in 10 cases,CT scanning in 4 cases,superior mesenteric ateriography in 2 cases and fiberoptic endoscopy in 7 cases.Results The locations of tumors at gastric were 7 cases,intestinal 2,lipper and row oseophagus to gastric cardiac in 1,respectively.The detective rate of GIST was 100%,75%,100% and 100% respectively by pneumobarium double contrast examination,CT,arteriography and fiberoptic endoscopy.Conclusion Pneumobarium double contrast examination and fiberoptic endoscopy are important methods for diagnosis of GIST.CT and arteriography can better show the location of tumors and differential diagnosis of benign and malignant of tumor.

BACKGROUNDLung cancer cell lines A549 and NCI-H446 with different radiosensitivity to ionizing radiation (IR) have different MDM2 gene expression status, which may contribute to the radioresistance of cells. The aim of this study is to use small interfering RNA (siRNA) targeting MDM2 to investigate the influence of MDM2 gene silencing on radioresponse of A549 cell.

METHODSPlasmid targeting MDM2 was constructed with pPUR/U6 vector and oligonucleotide designed according to the sequence of effective antisense oligonucleotides and principles of siRNA design. A549 cells were transfected by Lipofectamine™ 2000. MDM2 expression in A549 cells was detected by RT-PCR and Western blot. Radiation-mediated cell killing was detected by flow cytometry.

RESULTSTwo out of three siRNA plasmids were constructed successfully. siRNA transfection resulted in downregulaton of MDM2 expression of A549 cells on mRNA and protein levels. After treated with siRNA, radiation-mediated cell killing of A549 cells was significantly increased (P < 0.01).

CONCLUSIONSThe results support the hypothesis that MDM2 gene is a candidate for radioresistance in A549 cells. siRNA targeting to MDM2 can enhance the radiation-mediated cell killing of A549 cells.

Objective To investigate the changes of quantitative parameters of dynamic enhanced CT in non-small cell lung cancer before and after targeted therapy,and compare them with the traditional evaluation criteria,in order to find the parameters which can be exploited for timely,objective evaluation of the effect of targeted therapy.Methods The study included 21 patients with targeted therapy who had received dynamic enhanced CT before and after treatment.Enhancement time-density curves were obtained based on the CT values of the lesion at individual time points,and the functional indices:peak height (PH),the time to peak height (Tp),the ratio of PH of the mass to aorta (M/A) and perfusion value were calculated.The effects of the treatment on these indices were evaluated and compared with the effect of the treatment on lesion diameter. Results Twenty-one patients had 33 rechecking results. There was a statistically significant agreement between lesion diameter-based treatment evaluation and perfusion-based treatment evaluation ( U =8.761,P ＜ 0.01 ). The perfusion value decreased in patients with disease regression[before treatment:(0.28 ±0.11 ) ml · min-1 · ml-1,after targeted therapy(0.18 ±0.09) ml ·min-1 · ml-1,t =- 3.2722,P =0.0042],but increased in patients with disease progression[before treatment(0.21 ±0.08) ml · min-1 · ml-1,after targeted therapy:(0.34 ±0.11 ) ml · min-1 · ml-1,t =2.6064,P =0.0403].Conclusions On dynamic enhanced CT in non-small cell lung cancer patients after targeted therapy,perfusion value changed in the same trend as the diameter of tumor.The effectiveness of targeted therapy may be evaluated by perfusion value changes.