Copolymerization of chitosan selectively grafted by polyethylene glycol was prepared. Chitosan was selectively grafted by monomethoxy polyethylene glycol（mPEG-OH）, which contained a hydroxyl group combining with hex...Copolymerization of chitosan selectively grafted by polyethylene glycol was prepared. Chitosan was selectively grafted by monomethoxy polyethylene glycol（mPEG-OH）, which contained a hydroxyl group combining with hexamethylene diisocyanate（HDI） to form a novel macromonomer namely monomethoxy polyethylene glycol isocyanate（mPEG-NCO） containing a isocyanate group with higher chemical activity in ethyl glyoxalate solution absolutely without water. The selective grafted copolymerization of Chitosan with mPEG-NCO was conducted under heterogeneous conditions as suspension in dimethylformamide. The hydrophilic copolymers of chitosan were prepared by condensation reaction of isocyanate group on mPEG- NCO with hydroxy groups on chitosan chains because amino groups on chitosan chains were protected by complexion formation with copper ions. The effect of reaction condition on the grafting extents was discussed. Swelling properties of mPEG-g-CS were researched. The graft copolymer mPEG-g-CS was characterized by the infrared spectra. The experimental result showed that the copper ions were very effective to protect amino groups from condensation reaction. The swelling degree in water increases with adding of grafting ratio. The maximum swelling degree was up to above 132% when the grafting ratio was about 270%. The graft copolymer can be soluble partially in pure water.展开更多
BACKGROUND: The low graft-to-recipient weight ratio(GRWR) in adult-to-adult living donor liver transplantation(LDLT) is one of the major risk factors affecting graft survival. The goal of this study was to evaluate wh...BACKGROUND: The low graft-to-recipient weight ratio(GRWR) in adult-to-adult living donor liver transplantation(LDLT) is one of the major risk factors affecting graft survival. The goal of this study was to evaluate whether the lower limit of the GRWR can be safely reduced without portal pressure modulation in right-lobe LDLT. METHODS: From 2005 to 2011, 317 consecutive patients from a single institute underwent LDLT with right-lobe grafts without portal pressure modulation. Of these, 23 had a GRWR of less than 0.7%(group A), 27 had a GRWR of ≥0.7%, 【0.8%(group B), and 267 had a GRWR of more than and equal to 0.8%(group C). Medical records, including recipient, donor, operation factors, laboratory findings and complications were reviewed retrospectively. RESULTS: The baseline demographics showed low model for end-stage liver disease score(mean 16.3±8.9) and high percentage of hepatocellular carcinoma(231 patients, 72.9%). Three groups by GRWR demonstrated similar characteristics except recipient body mass index and donor gender. For smallforsize syndrome, there were 3(13.0%) in group A, 1(3.7%) in group B, and 2 patients(0.7%) in group C(P【0.001). Hepatic artery thrombosis was more frequently observed in group A than in groups B and C(8.7% vs 3.7% vs 1.9%, P=0.047). However, among the three groups, graft survival rates at 1 year(100% vs 96.3% vs 93.6%) and 3 years(91.7% vs 73.2% vs 88.1%) were not different(P=0.539). In laboratory measurements,there was no group difference in total bilirubin and albumin. However, prothrombin time was longer in group A within postoperative 1 week and platelet count was lower in groups A and B within postoperative 1 month. CONCLUSION: A GRWR lower to 0.7% is safe and does not need to modulate portal pressure in adult-to-adult LDLT using the right-lobe in favorable conditions including low model for end-stage liver disease score.展开更多
Background: Small-for-size graft(SFSG) has emerged as one of the very contentions in adult-to-adult living donor liver transplantation(LDLT) as a certain graft size is related to recipients’ prognosis. Graftto-recipi...Background: Small-for-size graft(SFSG) has emerged as one of the very contentions in adult-to-adult living donor liver transplantation(LDLT) as a certain graft size is related to recipients’ prognosis. Graftto-recipient weight ratio(GRWR)≥0.8% was considered as a threshold to conduct LDLT. However, this also has been challenged over decades as a result of technique refinements. For a better understanding of SFSG in practice, we conducted this meta-analysis to compare the perioperative outcomes and long-term outcomes between patients adopting the grafts with a lower volume(GRWR < 0.8%, SFSG group) and sufficient volume(GRWR ≥ 0.8%, non-SFSG group) in adult-to-adult LDLT. Data sources: The studies comparing recipients adopting graft with a GRWR < 0.8% and ≥ 0.8% were searched by three authors independently in Pub Med, Web of Science, Embase, the Cochrane Library, MEDLINE and Google Scholar databases until September 2018 and data were analyzed by RevMan 5.3.5. Results: Sixteen studies with a total of 3272 subjects were included in this meta-analysis. In terms of small-for-size syndrome(SFSS), no significant difference was found in subjects enrolled after year 2010(before 2010, OR = 3.00, 95% CI: 1.69–5.35, P = 0.0002;after 2010, OR = 1.23, 95% CI: 0.79–1.90, P = 0.36;P for interaction: 0.02). There was no significant difference in operative duration, blood loss, cold ischemia time, biliary complications, acute rejection, postoperative bleeding, hospitalization time, perioperative mortality, and 1-, 3-and 5-year overall survival rates between two groups. Conclusions: This meta-analysis suggested that adopting SFSG in adult LDLT has comparable outcomes to those with non-SFSG counterparts since 2010.展开更多
为进一步改善丙烯酰胺类聚合物在水基钻井液中的应用,采用水溶液聚合法合成了一种新型水溶性AMDMC-SSS-淀粉两性离子聚合物,探索了其合成条件以及在水基钻井液中的应用。结果表明,淀粉接枝聚合物的最佳合成条件为:在一定量淀粉溶液中,...为进一步改善丙烯酰胺类聚合物在水基钻井液中的应用,采用水溶液聚合法合成了一种新型水溶性AMDMC-SSS-淀粉两性离子聚合物,探索了其合成条件以及在水基钻井液中的应用。结果表明,淀粉接枝聚合物的最佳合成条件为:在一定量淀粉溶液中,引发剂质量分数为0.6%,丙烯酰胺、苯乙烯磺酸钠以及甲基丙烯酰氧乙基三甲基氯化铵质量分数分别为10.3%,10%,7.4%,聚合反应时间为3 h时接枝率最大。在钻井液性能评价实验中,淀粉共聚物加量为0.4%时,淡水钻井液的滤失量由16.5 m L降至7.0 m L,表现出较好的降滤失作用;表观粘度由8.0 m Pa·s增加至32.0 m Pa·s,表现出较强的提粘切能力;页岩回收率由38.5%提高至67.3%,淀粉共聚物具有较好的防塌性;页岩膨胀实验中,淀粉共聚物质量分数为0.5%时,页岩的线膨胀率由22.1%降至11.6%,表现出对页岩膨胀较好的抑制性能。展开更多
基金Funded by the Program of Beijing Municipal Commission of Education
文摘Copolymerization of chitosan selectively grafted by polyethylene glycol was prepared. Chitosan was selectively grafted by monomethoxy polyethylene glycol（mPEG-OH）, which contained a hydroxyl group combining with hexamethylene diisocyanate（HDI） to form a novel macromonomer namely monomethoxy polyethylene glycol isocyanate（mPEG-NCO） containing a isocyanate group with higher chemical activity in ethyl glyoxalate solution absolutely without water. The selective grafted copolymerization of Chitosan with mPEG-NCO was conducted under heterogeneous conditions as suspension in dimethylformamide. The hydrophilic copolymers of chitosan were prepared by condensation reaction of isocyanate group on mPEG- NCO with hydroxy groups on chitosan chains because amino groups on chitosan chains were protected by complexion formation with copper ions. The effect of reaction condition on the grafting extents was discussed. Swelling properties of mPEG-g-CS were researched. The graft copolymer mPEG-g-CS was characterized by the infrared spectra. The experimental result showed that the copper ions were very effective to protect amino groups from condensation reaction. The swelling degree in water increases with adding of grafting ratio. The maximum swelling degree was up to above 132% when the grafting ratio was about 270%. The graft copolymer can be soluble partially in pure water.
文摘BACKGROUND: The low graft-to-recipient weight ratio(GRWR) in adult-to-adult living donor liver transplantation(LDLT) is one of the major risk factors affecting graft survival. The goal of this study was to evaluate whether the lower limit of the GRWR can be safely reduced without portal pressure modulation in right-lobe LDLT. METHODS: From 2005 to 2011, 317 consecutive patients from a single institute underwent LDLT with right-lobe grafts without portal pressure modulation. Of these, 23 had a GRWR of less than 0.7%(group A), 27 had a GRWR of ≥0.7%, 【0.8%(group B), and 267 had a GRWR of more than and equal to 0.8%(group C). Medical records, including recipient, donor, operation factors, laboratory findings and complications were reviewed retrospectively. RESULTS: The baseline demographics showed low model for end-stage liver disease score(mean 16.3±8.9) and high percentage of hepatocellular carcinoma(231 patients, 72.9%). Three groups by GRWR demonstrated similar characteristics except recipient body mass index and donor gender. For smallforsize syndrome, there were 3(13.0%) in group A, 1(3.7%) in group B, and 2 patients(0.7%) in group C(P【0.001). Hepatic artery thrombosis was more frequently observed in group A than in groups B and C(8.7% vs 3.7% vs 1.9%, P=0.047). However, among the three groups, graft survival rates at 1 year(100% vs 96.3% vs 93.6%) and 3 years(91.7% vs 73.2% vs 88.1%) were not different(P=0.539). In laboratory measurements,there was no group difference in total bilirubin and albumin. However, prothrombin time was longer in group A within postoperative 1 week and platelet count was lower in groups A and B within postoperative 1 month. CONCLUSION: A GRWR lower to 0.7% is safe and does not need to modulate portal pressure in adult-to-adult LDLT using the right-lobe in favorable conditions including low model for end-stage liver disease score.
文摘Background: Small-for-size graft(SFSG) has emerged as one of the very contentions in adult-to-adult living donor liver transplantation(LDLT) as a certain graft size is related to recipients’ prognosis. Graftto-recipient weight ratio(GRWR)≥0.8% was considered as a threshold to conduct LDLT. However, this also has been challenged over decades as a result of technique refinements. For a better understanding of SFSG in practice, we conducted this meta-analysis to compare the perioperative outcomes and long-term outcomes between patients adopting the grafts with a lower volume(GRWR < 0.8%, SFSG group) and sufficient volume(GRWR ≥ 0.8%, non-SFSG group) in adult-to-adult LDLT. Data sources: The studies comparing recipients adopting graft with a GRWR < 0.8% and ≥ 0.8% were searched by three authors independently in Pub Med, Web of Science, Embase, the Cochrane Library, MEDLINE and Google Scholar databases until September 2018 and data were analyzed by RevMan 5.3.5. Results: Sixteen studies with a total of 3272 subjects were included in this meta-analysis. In terms of small-for-size syndrome(SFSS), no significant difference was found in subjects enrolled after year 2010(before 2010, OR = 3.00, 95% CI: 1.69–5.35, P = 0.0002;after 2010, OR = 1.23, 95% CI: 0.79–1.90, P = 0.36;P for interaction: 0.02). There was no significant difference in operative duration, blood loss, cold ischemia time, biliary complications, acute rejection, postoperative bleeding, hospitalization time, perioperative mortality, and 1-, 3-and 5-year overall survival rates between two groups. Conclusions: This meta-analysis suggested that adopting SFSG in adult LDLT has comparable outcomes to those with non-SFSG counterparts since 2010.
文摘为进一步改善丙烯酰胺类聚合物在水基钻井液中的应用,采用水溶液聚合法合成了一种新型水溶性AMDMC-SSS-淀粉两性离子聚合物,探索了其合成条件以及在水基钻井液中的应用。结果表明,淀粉接枝聚合物的最佳合成条件为:在一定量淀粉溶液中,引发剂质量分数为0.6%,丙烯酰胺、苯乙烯磺酸钠以及甲基丙烯酰氧乙基三甲基氯化铵质量分数分别为10.3%,10%,7.4%,聚合反应时间为3 h时接枝率最大。在钻井液性能评价实验中,淀粉共聚物加量为0.4%时,淡水钻井液的滤失量由16.5 m L降至7.0 m L,表现出较好的降滤失作用;表观粘度由8.0 m Pa·s增加至32.0 m Pa·s,表现出较强的提粘切能力;页岩回收率由38.5%提高至67.3%,淀粉共聚物具有较好的防塌性;页岩膨胀实验中,淀粉共聚物质量分数为0.5%时,页岩的线膨胀率由22.1%降至11.6%,表现出对页岩膨胀较好的抑制性能。
