Objective To discuss the diagnostic value of multi-slice spiral CT 2D and 3D reconstruction for atlantoaxial occult fracture.Methods Multi-slice spiral CT scans were performed in 38 patients who were suspected of fracture but were not detected with radiography,and the images were post-processed with Vitrea workstation(including MPR,MIP,VR and SSD).The images were observed by two experienced radiologists.Results Of 38 cases,28 cases were detected having small fractures with spiral CT reconstruction.Conclusion Multi-slice spiral CT 2D and 3D reconstructions are of important value in diagnosing atlantoaxial occult fracture.

The aim of this paper is to report the synthesis of the mPEG-PCL-g-PEI copolymers as small interfering RNA (siRNA) delivery vector, and exploration of the siRNA delivery potential of mPEG-PCL-g-PEI in vitro. The diblock copolymers mPEG-PCL-OH was prepared through the ring-opening polymerization. Then, the hydroxyl terminal (-OH) of mPEG-PCL-OH was chemically converted into the carboxy (-COOH) and N-hydroxysuccinimide (NHS) in turn to prepare mPEG-PCL-NHS. The branched PEI was reacted with mPEG-PCL-NHS to synthesize the ternary copolymers mPEG-PCL-g-PEI. The structure of mPEG-PCL-g-PEI copolymers was characterized with Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The mPEG-PCL-g-PEI/siRNA nanoparticles were prepared by complex coacervation, and the nanoparticles size and zeta potential were determined, separately. The cytotoxicities of mPEG-PCL-g-PEI/siRNA nanoparticles and PEI/siRNA nanoparticles were compared through cells MTT assays in vitro. The inhibition efficiencies of firefly luciferase gene expression by mPEG-PCL-g-PEI/ siRNA nanoparticle at various N/P ratios were investigated through cell transfection in vitro. The experimental results suggested that the ternary (mPEG5k-PCL(1.2k))1.4-g-PEI(10k) copolymers were successfully synthesized. (mPEG(5k)-PCL(1.2k))1.4-g-PEI(10k) could condense siRNA into nanoparticles (50-200 nm) with positive zeta potential. MTT assay results showed that the cytotoxicity of (mPEG(5k)-PCL(1.2k))1.4-g-PEI(10k)/siRNA nanoparticles was significantly lower than that of PEI(10k)/siRNA nanoparticles (P < 0.05). The expression of firefly luciferase gene could be significantly down-regulated at a range of N/P ratio from 50 to 150 (P < 0.01), and maximally inhibited at the N/P ratio of 125. The mPEG-PCL-g-PEI polymers could delivery siRNA into cells to inhibit the expression of target gene with very low cytotoxicity, which suggested that mPEG-PCL-g-PEI could serve as a new type of siRNA delivery vector.

Doxorubicin loaded micelles were prepared by film-hydration method using stearyl sulfadiazine (SA-SD) which is pH sensitive, methoxy (polyethylene glycol)-2000-1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine (mPEG-DOPE) and transactivator of transcription (TAT) peptide conjugated PEG-DOPE. Mean diameter of the pH-sensitive micelles was about 20 nm with a (99.1 +/- 2.1) % drug entrapment efficiency at pH 7.4. Flow cytometry studies revealed that the simple TAT micelles was taken up rapidly at the same level at pH 6.8 and pH 7.4. However, the pH-sensitive micelles entered the tumor cell less at pH 7.4 and significantly increase at pH 6.8. After 1 h incubation at pH 6.8, the amount of the pH-sensitive micelles taken up by cancer cell 4T1 was almost similar to simple TAT micelles. The confocal microscopy indicated that the pH-sensitive micelles entered the 4T1 cells at pH 6.8 more than at pH 7.4. It was indicated that the pH-sensitive micelles could shield TAT peptide at normal pH 7.4 and deshield it at pH 6.8. Hence, TAT peptides lead the drug-loaded micelles into the tumor cells and killed them selectively. The pH-sensitive micelle may provide a novel strategy for design of cancer targeting drug delivery system.

Objective To study the manifestations of MR of the tumor in jugular foramen area(JFA) and its diagnostic values.Methods 13 cases of tumors confirmed by pathology in JFA were reported,and the characteristics of MR of different kinds of tumor were analysed.Results There were its own MRI manifestations of different tumors in JFA,and the localizing and qualitative diagnosis of these tumors can be accurately made by MRI.Conclusion MRI is of very important diagnostic values in detecting the tumors in JFA.

Objective To explore the surgical methods in the treatment of carotid aneurysms. Methods A retros-pective analysis was made on the operations and results in 21 cases with 24 carotid aneurysms. Of the 24 carotid aneurysms, 18 were true and 6 false aneurysms. Nineteen cases underwent various operations including emergency operation in 3 cases. Carotid shunting device was used in 3 cases during operation. Results 2 cases were re-operated because of the recurrence of aneurysm,and 17 cases had satisfactory outcome without complications.None died in this series in perioperative period. Conclusions For carotid aneurysms,the first choice of treatment is syrgery.Surgical treatment is relatively safe and effective.

Objective To establish a simple and efficient method for developing a keloid model in nude mice with human keloid-derived fibroblasts.Methods Twenty-seven female BALB/c nude mice were randomly divided into five groups with 5,5,5,8 and 4 mice in group A,B,C,D and E respectively.The mice in group A,B and C were inoculated with 0.1 ml of suspension containing human keloid-derived fibroblasts at concentrations of 1.0 × 104,3.0 × 104 and 5.0 × 104 per microliter Matrigel,respectively,at the right axillary fossa.The tumors that formed in one mouse in group C were taken out,and cut into several parts measuring 5 mm × 5 mm × 5 mm in size,which were then subcutaneously transplanted into the right axillary fossa of mice in group D.The mice in group E were subcutaneously injected with 100 μl of Matrigel and served as the control group.The formation of tumor in mice was observed by naked eyes,and the size of tumors was measured until day 30 after tumor formation in group A,B and C as well as after tumor transplantation in group D.Mice were sacrificed on day 30 after tumor formation,and histopathologic examination was performed to analyze histological features of transplanted tumors and pathological changes in visceral organs such as heart,liver,spleen,lung and kidney.Results The tumor formation rate was consistently 100％ in group A,B and C,and the time required for tumor formation was (90.20 ± 3.96),(61.00 ± 2.92) and (39.60 ± 3.20) days in group A,B and C respectively.There was a significant difference in tumor volume on the 30th day after tumor formation between group A,B and C ((288.34 ± 25.29) vs.(1 370.63 ± 105.24) vs.(1 940.98 ± 184.37) mm3,F =138.74,P ＜ 0.05).The size of implanted tumor mass in group D firstly increased,then gradually decreased,but began to continuously increase since the 14~ day,and tumor finally formed in 7 out of 8 mice.There was no evidence of tumor formation in group E.Histopathologic examination showed uniform histological manifestations,which were similar to those of human scar,in tumor tissues from mice in group A,B,C and D.Neither pathological changes nor metastases were observed in visceral organs of these mice.Conclusion Keloid-bearing nude mouse model can be established by subcutaneous inoculation with human keloidderived fibroblasts,or by subcutaneous transplantation of tumor masses of a certain size that have formed in nude mice.

Objective To summarize our preliminary experience on diagnosis and treatment of aorta pseudoaneurysms due to deceleration injury. Methods Retrospective analysis was made on 8 cases of aorta pseudoaneurysms due to deceleration injury regarding its clinical findings, imagines and surgical operations or endografting treatment. Results Diagnosis was confirmed by imaging examinations. Among two cases who refused a surgery one died and the other lost follow-up after discharge. Surgery was successful in the remaining six cases including two cases treated by open surgery and four cases by intervensive endografting. Conclusions Aorta pseudoaneurysms due to deceleration injury can be correctly diagnosed by imaging examinations. Aorta pseudoaneurysms should be treated timely since spontaneous cure is almost impossible. Traditional surgical operations is effective, however, endografting is a relatively safe, less traumatic procedure.

ObjectiveTo explore the clinical significance of arterial portography in the diagnosis an d management of prehepatic type portal hypertension(PHPHT). Met hodsBetween 2000 to 2002, all the 11 patients with PHPHT were dia gnosed by angiography and B type ultrasounography. Different operations were par formed including mesocaval shunt in 5 patients,portal-vena cava shunt in 1, splenorenal shunt in 2,and portoazygos venous disconection in 1. Two patien ts were not operated. Results Nine cases undergoing surgical operations had satisfactory outcome. Conclusions PHPHT can be correctly diagnosed by indirect portal venography which is important for the choice of operation.

Objective To explore the treatment of left renal entrapment syndrome. Methods A retrospective analysis was made on the treatment of left renal entrapment syndrome. Diagnosis was established with ultrasonography, magnetic resonance angiography ( MRA) and left renal venography. The transposition of the superior mesenteric artery(SMA) was performed in three cases, the transposition of left renal vein( LRV) in two, and the stent implantation of the LRV in 15. Results Ultrasonography showed that the flow velocity of the proximal end of the LRV at horizontal position accelerates remarkably, and the acceleration is more obvious after standing for 15 minutes; The inner diameter ratio of the broadest place to the narrowest of the LRV at horizontal position is 4. 4?1. 6, while it is 8. 1?1.7 after standing for 15 minutes. MRA illustrated the angle between the abdominal aorta and the SMA was (30?5)?, the control was (64?16)?. The average pressure difference between the LRV and the inferior vena cava (IVC) was ( 14?5) mmHg and (2. 9?1. 4) mmHg before and after stent implantation. The surgical and interventional therapy was successful in all 20 cases. Follow-up from 6 months to 6 years revealed that macroscopic hematuria and symptom disappeared in all patients. Conclusion Ultrasonography, MRA and renal venography are decisive for the establishment of final diagnosis of left renal entrapment syndrome. The stent implantation is the choice of therapy because of less invasion.

Objective To evaluate the diagnostic value of MSCT in the differentiation of thymic epithelial tumours (TET)with the maximum diameter equal or less than 3 cm.Methods A retrospective analysis of pathological and imaging data of 56 patients with pathologically confirmed TET with the maximum diameter equal or less than 3 cm was performed.According to the 2004 WHO classification,56 TETs were classified as low-risk thymomas(types A/AB/B1),high-risk thymomas (types B2/B3)and thymic carcinomas (type C).The CT manifestations of TET in each group,including shape of tumor,tumor edge (smooth or spiculate protuberance), presence of small nodule around tumor,enhancement degree,pleura invasion and fat space around tumor,were analyzed retrospectively.The differences in the CT manifestations among three types were compared using chi-square test.If the sample number was too small, Fisher 's exact test was used.Results Compared with high-risk thymomas (23 cases)and thymic carcinomas (6 cases),regular round shape was more often observed in low-risk thymomas (27 cases)(χ2 =73,P <0.001;χ2 =116,P <0.001)and the mediastinum-lung interface was more likely to bulge (χ2 = 3.41,P =0.046;χ2 =7.39,P =0.01).Blurred edge,spiculate protuberance and pleural invasion and so on were significantly more common in high-risk thymomas and thymic carcinomas (P <0.001)and they were the most common in thymic carcinomas (χ2 =11.5,P =0.009).There was a significant difference between type B2 thymomas and thymic carcinomas (χ2 =31.52, P <0.001),however there was no significant difference between type B3 thymomas and thymic carcinomas (χ2 =6.96,P =0.07). Conclusion MSCT can accurately show the shape of tumor,tumor edge,presence of small nodule around tumor,enhancement degree,pleura invasion,which can predict the histologic type of thymomas and also can provide information for preoperative diagnosis and prognosis evaluation.