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Objective: To establish the N-nitroso-bis (2 - oxopropyl) amine [N-Nitrosobis (2-oxopropyl) amine, the BOP] the inducible golden hamster pancreatic cancer model to explore the golden hamster pancreas and pancreatic MR performance . MATERIALS AND METHODS: 101 female Syrian golden hamster take random row list according to the size of body mass, were randomly divided into three groups: healthy group (group 1), 5 for normal golden hamster pancreas anatomy and MR imaging studies. The BOP treatment group (group 2), 80, were divided into 8 subgroups, subcutaneous injection of the BOP 10mg · kg-1 · W-1, respectively, for seven weeks, the establishment of BOP-induced pancreatic cancer model; NACL treatment group (group 3), 16, were divided into eight sub-groups were injected subcutaneously with normal saline control group as a model. All mice using GE 1.5T MR scanner and use the mouse dedicated animal experiments coil line cross-sectional and coronal MR imaging, scanning sequence for cross-sectional the SE T1W.SPGR T1W.FRFSE T2W coronal SPGR T1W FRFSE T2W. Will the MR data transmission to GEAW4.1 workstation. In the first group, observed: ① pancreatic morphology, size and contour; ② pancreas distribution; the adjacent relationship ③ pancreas signal characteristics: ④ pancreas. Scan after laparotomy observation, found with the MR control; plastic hose filled with water placed around in the pancreas, the abdominal organs and tissue after reduction, the second MR scan to pancreatic MR performance. Excessive anesthesia were killed by a hamster, and completely remove the pancreas for anatomical and histological study. 11 weeks after the first injection, every two weeks, to 25 weeks, Group 2 and Group 3 MR imaging. Observed on MRI: ① tumor located on the site of the pancreas; ② number of tumors; (3) tumor shape, contour; (4) measurement of tumor size and volume relationship ⑤ tumor and surrounding tissue. ⑥ tumor signal characteristics. After each MR scan immediately put to death each one subgroup laparotomy naked eye control found with MR naked eye observation record pancreatic tumor to complete remove specimens, said the quality of the tumor, measuring tumor diameter and volume; 10% formalin fixed specimens, embedded in paraffin, conventional sections, HE staining slice line histopathological diagnosis by the pathologist. BOP-induced pancreatic lesions progression into atypical ductal hyperplasia (atypical ductal hyperplasia, ATH), carcinoma in situ (carcinoma in situ, CIS), invasive carcinoma (invasive carcinoma, CA) into three categories. Results: in vivo golden hamster pancreas was pale pink coated transparent serosa, divided into clover, that leaves the stomach, spleen leaf, duodenum leaf confluence at the head of the pancreas, was the kind of clover. The five healthy golden hamster pancreas, stomach leaves, spleen leaves, duodenum leaves length were 19.60 ± 3.21mm, 22.40 ± 3.05mm and 9.40 ± 2.07mm. Duodenum leaves shortest, compared with the other two leaves, the differences were statistically significant (p = 0.000); the stomach leaves, spleen leaf long diameter difference was not statistically significant (p gt; 0.05). The the stomach leaves, spleen leaves, the duodenum leaves short diameter were 5.26 ± 0.67mm, 4.98 ± 0.47mm, 5.48 0.63mm, three difference was not statistically significant (F = 0.891, p gt; 0.05). On MRI, the spleen leaves, stomach leaves the duodenum leaves, pancreatic display in 5,4,3,4-only mice; pancreatic four showed 2 2; three ; two display one. The spleen leaves elongated, located in the spleen, stomach, left kidney between the tail of the pancreas up to the splenic hilum; stomach leaves the trailing edge is located in the stomach wall and the right edge; the duodenal lobe located antral, close to 10 duodenum, irregular shape; the trefoil structure confluence at the head of the pancreas. Uniform signal of the pancreas, we can see a clear outline. T1W on the the golden hamster normal pancreatic signal strength is lower than the liver, T2W signal intensity than liver parenchyma, with different MR signal characteristics of normal human pancreas. In all scanning sequence, the the pancreas main pancreatic duct and collateral pancreatic duct were no show. The naked eye, the second group of 18 golden hamsters found 23 of pancreatic cancer, which, one found that three pancreatic tumors, found that two in three, the rest are single. Among them, seven tumor diameter lt; 5.0 mm the 16 tumor diameter ≥ 5.0mm, the smallest tumor diameter 2.0mm, maximum tumor diameter of 17.0mm. Median tumor diameter in 6.8mm, volume median 178.7mm3, the mass median 0.32 g. Pancreatic nodules found as early as 15 weeks after 1st injection BOP. Most tumors were pink or red meat, part of the tumor to the red and white color. Part of the surface of the tumor is not structured, slightly lobulated. Cut open the tumor, visible bleeding and necrosis. Large tumor and surrounding tissue structure boundaries unclear, not easy to peel. Histopathology confirmed, 11 weeks after the first injection BOP, a subgroup of the experimental group, 5 mice found that varying degrees of pancreatic ATH; Total found 65 ATH (81.3%, 65/80). Group 2 31 of pancreatic cancer was found in 26 mice were pancreatic ductal adenocarcinoma (pancreatic ductal adenocarcinomas, PDAs), the incidence rate of 32.5% (26/80). CIS, which, as early as 13 weeks after 1st injection BOP found a total of nine mice found nine CIS (29.0%, 9/31); CA, experimental group of 17 mice as early as 19 weeks found 22 CA (71.0%, 22/31). All tumor-bearing mice were accompanied by ATH, all hamsters were not found not found ATH PDAs. Naked eye found 23 tumors, 20 to CA, the CIS; 8 failed to detect with the naked eye PDAs in two of the CA for the CIS. Visible in PDAs surrounding connective tissue hyperplasia and inflammatory cell response. The completion of the second group of 75 golden hamsters or MR scan; accumulated 210 MR scan. Accumulated in the 40 MR scan found 15 tumors in 15 mice, which, the head of the pancreas in two (2/15, 13.3%); spleen leaves seven (7/15, 46.7%); stomach leaves five (5 / 15,33.3%); the duodenum leaves 1 (1/15, 6.7%). MR naked eye tumor detection rate was 65.2% (15/23). MR measurements of tumor diameter was 7.80 ± 3.19mm, which, two tumors (2/15, 13.3%) diameter less than 5.0mm; 13 tumors (13/15, 86.7%) diameter greater than / equal to 5.0mm. MR measurements of the largest and the smallest volume were 1642.60mm3 and 15.06mm3. At the earliest time after injection of BOP 19 tumor was found in the stomach leaves a diameter of about 3.0 mm. MR measuring volume and tumor mass correlation coefficient of 0.96 (p = 0.000, n = 15). Diameter of 2 the MR found 15 tumors less than 5.0mm tumor signal uniformity, morphological rules, clear boundaries, T1WI showed low signal, T2WI showed high signal; 13 diameter greater than / equal to 5.0mm tumor performance is uneven, irregular shape, signal levels are not clear. The histological examination confirmed the MR found 15 tumors were PDAs. Conclusion: golden hamster pancreas into stomach leaves, the spleen leaves, the duodenum leaves of clover, convergence at the head of the pancreas, was clover-like. Use the mouse dedicated animal experiments coil combined cross-sectional and coronal scans, MRI can clearly show the Golden Hamster normal pancreas. 3 golden hamster normal pancreatic signal intensity lower than the liver, T2W signal intensity higher than the liver parenchyma, with different MR signal characteristics of normal human pancreas. 4 successfully established by subcutaneous injection of BOP induced golden hamster pancreatic cancer animal model. 5.BOP induced pancreatic lesions include ATH, CIS, CA, into three categories, reveals pancreatic cancer occurrence and development process. The 6.BOP induced hamster pancreatic cancer are PDAs, associated with connective tissue hyperplasia and inflammatory cell response with human pancreatic approximation. 7.MRI early detection BOP induced golden hamster pancreatic cancer, and can accurately describe the characteristics of pancreatic cancer. 8.MR measurement volume has a high correlation with the tumor mass and the precise reaction tumor volume change can be used to monitor tumor development, change. 9.MRI perhaps for pancreatic cancer treatment response monitoring and evaluation.
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