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Objective:To investigate the physicochemical and biological properties of different magnesium modified calcium phosphate bone cements.Methods:The different magnesium modified calcium phosphate bone cements were divided into magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate groups, each of which was added with different magnesium agents in the proportion of 0%, 1%, 3% and 5% of the total weight of calcium phosphate bone cements. The initial and final setting time, injectability, anti-collapse performance and compressive strength of different magnesium modified calcium phosphate bone cements were tested. Furthermore, the screened bone cement extracts were used to culture with third generation osteoblasts. Bioactivity assays were performed using the Cell Proliferation and Toxicity Assay Kit (CCK-8). Alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining were performed on osteoblasts to observe the osteogenic activity of magnesium malate modified calcium phosphate bone cements.Results:The addition of different proportions of different magnesium agents led to the shortening of the initial and final setting time of modified calcium phosphate bone cements. Moreover, the final setting time of 5% magnesium malate modified calcium phosphate bone cements was the shortest (<40 minutes), which was significantly shorter compared with other magnesium agents in the same proportion (all P<0.05). With the addition of different magnesium agents in different proportions, the injectability of bone cements was gradually increased, and the injectability of 5% magnesium malate calcium phosphate bone cements reached the highest for (87.3±1.9)%, which was significantly increased compared with other magnesium agents in the same proportion (all P<0.05). The anti-collapse performance of bone cements was decreased with the addition of different magnesium agents in different proportions. Magnesium citrate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements could not resist the flushing of deionized water. In particular, magnesium malate modified calcium phosphate bone cements had the best anti-collapse performance, with the maximum weight loss rate for only (9.8±2.3)% after 30 minutes of deionized water flushing, which was better than the rest of the groups (all P<0.05). The compressive strength of magnesium lactate and magnesium phosphate modified calcium phosphate bone cements showed a decrease compared with original calcium phosphate bone cements, while the compressive strength of magnesium citrate and magnesium malate modified calcium phosphate bone cements was significantly increased compared with original calcium phosphate bone cements, of which 3% magnesium malate modified calcium phosphate bone cements had the greatest compressive strength of (6.2±0.2)MPa, significantly higher than the rest of the groups (all P<0.05). The sieve test yielded magnesium malate modified calcium phosphate bone cement, which had a weight loss of (27.0±0.9)% at 35 days in vitro. The release of magnesium ions was increased with increasing magnesium malate dose in the in vitro environment of magnesium malate modified calcium phosphate bone cements in different ratios. A stable magnesium ion release was achieved within 35 days.Also, the pro-proliferative and osteogenic effects of modified calcium phosphate bone cements on osteoblasts were more obvious with increase of magnesium malate dose. For 5% magnesium malate modified calcium phosphate bone cements, the cell number, ALP staining area ratio and calcium nodule area ratio were significantly increased compared with the groups in the proportion of 0% and 1% magnesium malate (all P<0.05). Conclusions:Among magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements, magnesium malate modified calcium phosphate bone cements have relatively suitable setting time, excellent anti-collapse performance and mechanical strength. Meanwhile, 5% magnesium malate modified calcium phosphate bone cements have better biological activity among different ratios of magnesium malate modified calcium phosphate bone cements, suggesting a potential value for clinical application.
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PurposeGas is rarely studied or reported to be used as a contrast agent of stomach MRI examination because it might lead to susceptibility artifacts, the purpose of this study is to evaluate the application value of gas as a contrast agent of stomach MRI examination.Materials and Methods Sixty patients who were supposed to have upper abdominal MRI examination were enrolled, all patients were given intramuscular injection of 654-2, gas from oral ingestion of aerogenic powder was used as contrast agent, MRI examinations were then executed and images quality of MRI were analyzed and classified. Results All 60 patients felt it acceptable for the taste of aerogenic powder, only 5 cases felt uncomfortable during swallowing; no adverse reactions were observed in all the 60 cases. Excellent gas contrast medium filling of the stomach cavity were confirmed with CT scanning in 57 cases (95%). Gas acted as a negative contrast agent in the stomach cavity with good continuity and uniform signal; and the proximal part of the stomach and duodenum was well displayed. There were 21 cases (35.0%) classified as grade 0 about their image quality; 25 cases (41.7%) as grade 1; 6 cases (10.0%) as grade 2; 8 cases (13.3%) as grade 3, with total 52 cases (86.7%) with image quality which could meet the requirement of clinical diagnosis. Cases of grade 0-2 showed coronary T2WI images with vivid stomach contour and clear stomach wall with no artifacts; axial FS-T2WI images with few artifacts, relative clear stomach contour and good display of stomach wall; less artifact could be found in axial TIWI image with good display of stomach wall; axial T2WI images showed more artifacts and gastric wall was displayed not clear enough. Cases classified as grade 3 showed coronal T2WI, FS-T2WI, T1WI and T2WI axial images with significant artifacts, vague outline, distortions or ghosting of the contour of stomach and tumor.Conclusion As contrast agent for gastric MRI examination, gas is safe, homogeneously distributed with stable signal characteristic and is easy for patients to tolerate.
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Objective The gross appearance and histopathology as well a s the treatment of early colorectal carcinoma were investigated. Methods The clinical documents and histopathology of 105 cases(106 lesions) with early color ectal carcinoma detected by colonoscopy and proved pathologically after operatio n in past 16 years were retrospectively reviewed and analysed. Results 91.5％ of the early colorectal carcinoma were located distal to the sigmoid.The macro scopic type of these lesions under colonoscopy was classified as Ip type in 34 l esions,Ips type in 13,Is type in 26,Ⅱ a type in 11,Ⅱ a＋Ⅱ c type in 22(in whi ch 21 lesions are Sm carcinoma).Lymph node involvement was observed in 3 cases o f the 25 with Sm carcinoma (accounting for 12％ ).13 lesions(in 12 cases)were re moved under the colonoscopy,local recurrence was found in one case of Sm carcino ma during the follow up period and treated with radical operation.93 lesions(in 93 cases)were treated by local resection or radical surgery. Conclusions Most of the carcinomas withⅡ a＋Ⅱ c type were sm carcinoma.Histopathologically mos t of Sm carcinomas were poorly or moderately differentiated adenocarcinomas.Lymp h node involvement only appeared in Sm carcinoma.Radical operation should be per formed in the following conditions (1)the macroscopic type isⅡ a＋Ⅱ c type,(2) the histopathologic type is poorly differentiated adenocarcinoma,(3)involvement of submucosa or lymph node metastasis
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Objective To investigate the features of pit patterns by magnifying endoscopy on neo-plastic colorectal polyps. Methods The materials consisted of 129 polyps in 108 patients. Dye-assisted magnifying endoscopies were used to ascertain the pit patterns of polyps. Results Of 129 polyps, 106 were diagnosed pathologically as neoplastic lesions(adenomas and carcinomas) , in which 10 demonstratedⅡpit pattern with only mild to moderate atypia and no severe atypia; 73 ⅢL pit pattern; 1Ⅲs pit pattern; 7 Ⅳ pit pattern and 15 Ⅴ pit patterns which includes malignant change in 10 cases, and severe atypia in 5 cases. Ten lesions all demonstrated Ⅴ pit pattern were found to be carcinoma (7 mucosal and 2 submucosal and 1 advanced carcinomas). Of 7 mucosal carcinomas,6 showed ⅤA pit pattern,1 , Ⅴ N pit pattern; 2 submuco-sal carcinomas all showed VN pit pattern; 1 advanced carcinoma showed ⅤN pit pattern. Ten lateral sprea-ding tumors were also investigated, their pit patterns under magnifying endoscopy were Ⅲ LⅥor V pit pat-tern among them one case with malignant change. Conclusion The images of pit pattern obtained by magnif-ying endoscopy were essentially concordance to those provided by stereomicroscopy. The differentiation of tu-morous lesion or non-tumorous lesion can be fairly performed under the observation of pit patterns; it gives an important practical significance in diagnosing tumorous lesions.