未亡时间偏倚(immortal time bias)又称为保证时间偏倚(guarantee time bias),是一种特殊的选择性偏倚^([1]),广泛地存在于观察性研究和药物临床试验中。Gail^([2])分析心脏移植的研究时,首次提出了未亡时间偏倚,认为移植组生存时间的延...未亡时间偏倚(immortal time bias)又称为保证时间偏倚(guarantee time bias),是一种特殊的选择性偏倚^([1]),广泛地存在于观察性研究和药物临床试验中。Gail^([2])分析心脏移植的研究时,首次提出了未亡时间偏倚,认为移植组生存时间的延长,部分归因于未亡时间偏倚的存在。展开更多
AIM： To evaluate immunological protection of nitric ox- ide （NO） in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion （IR） injury in rat liver transplantation, METHODS： Sixty-six healthy m...AIM： To evaluate immunological protection of nitric ox- ide （NO） in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion （IR） injury in rat liver transplantation, METHODS： Sixty-six healthy male Wistar rats were randomly divided into three groups （11 donor/recipi-ent pairs）. In group 11, organ preservation solution was lactated Ringer＇s solution with heparin 10 000/μL at 4℃. In groups I and 111, the pLeservation solution added, respectively, L-arginine or Ng-L-arginine methyl ester （L-NAME） （1 mmol/L） based on group 11, and recipients were injected with L-arginine or L-NAME （50 mg/kg） in the anhepatic phase. Grafted livers in each group were stored for 6 h and implanted into recipi- ents. Five rats were used for observation of postopera- tive survival in each group. The other six rats in each group were used to obtain tissue samples, and execut- ed at 3 h and 24 h after transplantation. The levels of alanine aminotransferase （ALT）, tumor necrosis factor （TNF）-a and NO metabolites （NOx） were detected, and expression of NO synthase, TNF-α and intercellular adhesion molecule 1 （ICAM-1） was examined by tri- phosphopyridine nucleotide diaphorase histochemical and immunohistochemical staining. RESULTS： By supplementing L-arginine to strengthen the NO pathway, a high survival rate was achieved and hepatic function was improved. One-week sur- viral rate of grafted liver recipients in group I was significantly increased （28.8 4±36.6 d ys 4 4±1.7 d, P 〈 0.01） as compared with groups 11 and Ill. Serum levels of ALT in group ] were 2-7 times less than those in groups 11 and 11I （P 〈 0.01）. The cyclic guanosine monophosphate （cGMP） levels in liver tissue and NOx in group I were 3-4 times higher than those of group 11 after 3 h and 24 h reperfusion, while in group ]]], they were significantly reduced as compared with those in group ]1 （P 〈 0.01）. The levels of TNF-（z in group I were significantly lower than in group Ⅱ after 3 h and 24 h reperfusion （P 〈 0.01）, while being sig- nificantly higher in group Ⅲ than group Ⅱ （P 〈 0.01）. Histopathology revealed more severe tissue damage in graft liver and lung tissues, and a more severe in- flammatory response of the recipient after using NO synthase inhibitor, while the pathological damage to grafted liver and the recipient＇s lung tissues was signifi-cantly reduced in group I after 3 h and 24 h reperfu- sion. A small amount of constitutive NO synthase （cNOS） was expressed in liver endothelial cells after 6 h cold storage, but there was no expression of inducible NO synthase （iNOS）. Expression of cNOS was particularly significant in vascular endothelial cells and liver cells at 3 h and 24 h after reperfusion in group Ⅱ but expres- sion of iNOS and ICAM-1 was low in group I. There was diffuse strong expression of ICAM-1 and TNF-α in group Ⅱ at 3 h after reperfusion. CONCLUSION： The NO/cGMP pathway may be critical in successful organ transplantation, especially in treat- ing hepatopulmonary syndrome during cold IR injury in rat orthotopic liver transplantation.展开更多
AIM： To study the immuno-modulatory effect of resveratrol （RES） on allograft rejection after liver transplantation in rats. METHODS： Male Sprague-Dawley （SD） rats were selected as donors and male Wistar rats as ...AIM： To study the immuno-modulatory effect of resveratrol （RES） on allograft rejection after liver transplantation in rats. METHODS： Male Sprague-Dawley （SD） rats were selected as donors and male Wistar rats as recipients for a rejection model. The recipients were divided into four groups after orthotopic liver transplantation （OLTx）. In the RES A, B, and C groups, RES was given intra-peritoneally once a day （25, 50, and 100 mg/kg, respectively） after OLTx, whereas in the control group, vehicle buffer was given intra-peritoneally once a day. The survival time, serum chemistry, production of cytokines, activation of transcription factor NF-kB, and histopathologic findings were then compared among these groups. RESULTS： The mean survival time after OLTx in the RES C group was significantly longer than that in the control group （16.7＋-1.2 d ,vs9.3＋-0.6 d, P〈0.01）. On the 7th posttransplant day the serum albumin level significantly improved in the RES C group, the serum total bile acid and alanine aminotransferase （ALT） levels were significantly lower in the RES C group, the serum IL-2 and INF-y levels were significantly lower in the RES C group, and the activation of transcription factor NF-kB in peripheral blood T lymphocytes was significantly suppressed in the RES A, B, and C groups in comparison to those in the control group. On the 7^th post-transplant day, a histological examination revealed apparent difference in the severity of rejection between the RES C group and control group. CONCLUSION： RES has an immuno-suppressive property as well as protective effect on hepatocytes under allograft rejection. It might serve as a novel agent for reducing the severity of hepatic allograft rejection in rats.展开更多
AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to ...AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury. METHODS: The rats were randomized into five groups, WIT was 0,15,30,45,60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation. RESULTS: The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min. CONCLUSION: Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.展开更多
To evaluate if any association existed between the extent of hepatic necrosis in initial liver biopsies and patient survival.METHODSThirty-seven patients with fulminant liver failure, whose liver biopsy exhibited subs...To evaluate if any association existed between the extent of hepatic necrosis in initial liver biopsies and patient survival.METHODSThirty-seven patients with fulminant liver failure, whose liver biopsy exhibited substantial necrosis, were identified and included in the study. The histological and clinical data was then analyzed in order to assess the relationship between the extent of necrosis and patient survival, with and without liver transplantation. The patients were grouped based on the etiology of hepatic necrosis. Each of the etiology groups were then further stratified according to whether or not they had received a liver transplant post-index biopsy, and whether or not the patient survived.RESULTSThe core tissue length ranged from 5 to 44 mm with an average of 23 mm. Causes of necrosis included 14 autoimmune hepatitis, 10 drug induced liver injury (DILI), 9 hepatitis virus infection, and 4 unknown origin. Among them, 11 showed submassive (26%-75% of the parenchymal volume) and 26 massive (76%-100%) necrosis. Transplant-free survival was worse in patients with a higher extent of necrosis (40%, 71.4% and 100% in groups with necrosis of 76%-100%, 51%-75% and 26%-50%, respectively). Additionally, transplant-free survival rates were 66.7%, 57.1%, and 25.0% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively. Even after liver transplantation, the survival rate in patients as a result of viral hepatitis remained the lowest (80%, 100%, and 40% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively).CONCLUSIONAdequate liver biopsy with more than 75% necrosis is associated with significant transplant-free mortality that is critical in predicting survival.展开更多
Background： Endothelial and smooth muscle cells were used as seeding cells and heterogeneous acellularized matrix was used as scaffold to construct the tissue-engineered graft. Methods： A 2 weeks piglet was selected...Background： Endothelial and smooth muscle cells were used as seeding cells and heterogeneous acellularized matrix was used as scaffold to construct the tissue-engineered graft. Methods： A 2 weeks piglet was selected as a donor of seeding cells. Two-centimetre length of common carotid artery was dissected. Endothelial cells and smooth muscle cells were harvested by trypsin and collagenase digestion respectively. The isolated cells were cultured and expanded using routine cell culture technique. An adult sheep was used as a donor of acellularized matrix. The thoracic aorta was harvested and processed by a multi-step decellularizing technique to remove the original cells and preserve the elastic and collagen fibers. The cultured smooth muscle cells and endothelial cells were then seeded to the acellularized matrix and incubated in vitro for another 2 weeks. The cell seeded graft was then transplanted to the cell-donated piglet to substitute part of the native pulmonary artery. Results： The cultured cells from piglet were characterized as endothelial cells by the presence of specific antigens vWF and CD31, and smooth muscle cells by the presence of specific antigen a-actin on the cell surface respectively with immunohistochemical technique. After decellularizing processing for the thoracic aorta from sheep, all the cellular components were extracted and elastic and collagen fibers kept their original morphology and structure. The maximal load of acellular matrix was decreased and 20% lower than that of untreated thoracic aorta, but the maximal tensions between them were not different statistically and they had similar load-tension curves. Three months after transplantation, the animal was sacrificed and the graft was removed for observation. The results showed that the inner surfaces of the graft were smooth, without thrombosis and calcification. Under microscopy, a great number of growing cells could be seen and elastic and collagen fibers were abundant. Conclusion： Cultured self-derived endothelial and smooth muscle cells could be used as seeding cells and heterogeneous acellularized matrix could be used as scaffold in constructing tissue-engineered graft.展开更多
文摘未亡时间偏倚(immortal time bias)又称为保证时间偏倚(guarantee time bias),是一种特殊的选择性偏倚^([1]),广泛地存在于观察性研究和药物临床试验中。Gail^([2])分析心脏移植的研究时,首次提出了未亡时间偏倚,认为移植组生存时间的延长,部分归因于未亡时间偏倚的存在。
文摘AIM： To evaluate immunological protection of nitric ox- ide （NO） in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion （IR） injury in rat liver transplantation, METHODS： Sixty-six healthy male Wistar rats were randomly divided into three groups （11 donor/recipi-ent pairs）. In group 11, organ preservation solution was lactated Ringer＇s solution with heparin 10 000/μL at 4℃. In groups I and 111, the pLeservation solution added, respectively, L-arginine or Ng-L-arginine methyl ester （L-NAME） （1 mmol/L） based on group 11, and recipients were injected with L-arginine or L-NAME （50 mg/kg） in the anhepatic phase. Grafted livers in each group were stored for 6 h and implanted into recipi- ents. Five rats were used for observation of postopera- tive survival in each group. The other six rats in each group were used to obtain tissue samples, and execut- ed at 3 h and 24 h after transplantation. The levels of alanine aminotransferase （ALT）, tumor necrosis factor （TNF）-a and NO metabolites （NOx） were detected, and expression of NO synthase, TNF-α and intercellular adhesion molecule 1 （ICAM-1） was examined by tri- phosphopyridine nucleotide diaphorase histochemical and immunohistochemical staining. RESULTS： By supplementing L-arginine to strengthen the NO pathway, a high survival rate was achieved and hepatic function was improved. One-week sur- viral rate of grafted liver recipients in group I was significantly increased （28.8 4±36.6 d ys 4 4±1.7 d, P 〈 0.01） as compared with groups 11 and Ill. Serum levels of ALT in group ] were 2-7 times less than those in groups 11 and 11I （P 〈 0.01）. The cyclic guanosine monophosphate （cGMP） levels in liver tissue and NOx in group I were 3-4 times higher than those of group 11 after 3 h and 24 h reperfusion, while in group ]]], they were significantly reduced as compared with those in group ]1 （P 〈 0.01）. The levels of TNF-（z in group I were significantly lower than in group Ⅱ after 3 h and 24 h reperfusion （P 〈 0.01）, while being sig- nificantly higher in group Ⅲ than group Ⅱ （P 〈 0.01）. Histopathology revealed more severe tissue damage in graft liver and lung tissues, and a more severe in- flammatory response of the recipient after using NO synthase inhibitor, while the pathological damage to grafted liver and the recipient＇s lung tissues was signifi-cantly reduced in group I after 3 h and 24 h reperfu- sion. A small amount of constitutive NO synthase （cNOS） was expressed in liver endothelial cells after 6 h cold storage, but there was no expression of inducible NO synthase （iNOS）. Expression of cNOS was particularly significant in vascular endothelial cells and liver cells at 3 h and 24 h after reperfusion in group Ⅱ but expres- sion of iNOS and ICAM-1 was low in group I. There was diffuse strong expression of ICAM-1 and TNF-α in group Ⅱ at 3 h after reperfusion. CONCLUSION： The NO/cGMP pathway may be critical in successful organ transplantation, especially in treat- ing hepatopulmonary syndrome during cold IR injury in rat orthotopic liver transplantation.
文摘AIM： To study the immuno-modulatory effect of resveratrol （RES） on allograft rejection after liver transplantation in rats. METHODS： Male Sprague-Dawley （SD） rats were selected as donors and male Wistar rats as recipients for a rejection model. The recipients were divided into four groups after orthotopic liver transplantation （OLTx）. In the RES A, B, and C groups, RES was given intra-peritoneally once a day （25, 50, and 100 mg/kg, respectively） after OLTx, whereas in the control group, vehicle buffer was given intra-peritoneally once a day. The survival time, serum chemistry, production of cytokines, activation of transcription factor NF-kB, and histopathologic findings were then compared among these groups. RESULTS： The mean survival time after OLTx in the RES C group was significantly longer than that in the control group （16.7＋-1.2 d ,vs9.3＋-0.6 d, P〈0.01）. On the 7th posttransplant day the serum albumin level significantly improved in the RES C group, the serum total bile acid and alanine aminotransferase （ALT） levels were significantly lower in the RES C group, the serum IL-2 and INF-y levels were significantly lower in the RES C group, and the activation of transcription factor NF-kB in peripheral blood T lymphocytes was significantly suppressed in the RES A, B, and C groups in comparison to those in the control group. On the 7^th post-transplant day, a histological examination revealed apparent difference in the severity of rejection between the RES C group and control group. CONCLUSION： RES has an immuno-suppressive property as well as protective effect on hepatocytes under allograft rejection. It might serve as a novel agent for reducing the severity of hepatic allograft rejection in rats.
基金Supported by the Key Clinical Project of Minister of Public Health,No. 97040230 Scientific and Technological Committee of Guangdong Province, No. 99M4902G
文摘AIM:To investigate the changing patterns of glycogen and enzyme histochemical activities in rat liver graft under a different warm ischemia time (WIT) and to predict the tolerant time limitation of the liver graft to warm ischemia injury. METHODS: The rats were randomized into five groups, WIT was 0,15,30,45,60 min, respectively, and histochemical staining of liver graft specimens was observed. The recovery changes of glycogen and enzyme histochemistry activities were measured respectively 6 and 24 h following liver graft implantation. RESULTS: The activities of succinic dehydrogenase, cytochrome oxidase, apyrase (Mg++-ATPase) and content of glycogen were decreased gradually after different WIT in a time-dependent manner. The changes were significant when WIT was over 30 min. CONCLUSION: Hepatic injury is reversible within 30 min of warm ischemia injury. Glycogen and enzyme histochemistry activities of liver grafts and their recovery potency after reperfusion may serve as criteria to evaluate the quality of liver grafts.
文摘To evaluate if any association existed between the extent of hepatic necrosis in initial liver biopsies and patient survival.METHODSThirty-seven patients with fulminant liver failure, whose liver biopsy exhibited substantial necrosis, were identified and included in the study. The histological and clinical data was then analyzed in order to assess the relationship between the extent of necrosis and patient survival, with and without liver transplantation. The patients were grouped based on the etiology of hepatic necrosis. Each of the etiology groups were then further stratified according to whether or not they had received a liver transplant post-index biopsy, and whether or not the patient survived.RESULTSThe core tissue length ranged from 5 to 44 mm with an average of 23 mm. Causes of necrosis included 14 autoimmune hepatitis, 10 drug induced liver injury (DILI), 9 hepatitis virus infection, and 4 unknown origin. Among them, 11 showed submassive (26%-75% of the parenchymal volume) and 26 massive (76%-100%) necrosis. Transplant-free survival was worse in patients with a higher extent of necrosis (40%, 71.4% and 100% in groups with necrosis of 76%-100%, 51%-75% and 26%-50%, respectively). Additionally, transplant-free survival rates were 66.7%, 57.1%, and 25.0% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively. Even after liver transplantation, the survival rate in patients as a result of viral hepatitis remained the lowest (80%, 100%, and 40% in groups of autoimmune hepatitis, DILI, and viral hepatitis, respectively).CONCLUSIONAdequate liver biopsy with more than 75% necrosis is associated with significant transplant-free mortality that is critical in predicting survival.
基金Project (No. 99ZB14018) supported by the Natural Science Foun-dation of Shanghai, China
文摘Background： Endothelial and smooth muscle cells were used as seeding cells and heterogeneous acellularized matrix was used as scaffold to construct the tissue-engineered graft. Methods： A 2 weeks piglet was selected as a donor of seeding cells. Two-centimetre length of common carotid artery was dissected. Endothelial cells and smooth muscle cells were harvested by trypsin and collagenase digestion respectively. The isolated cells were cultured and expanded using routine cell culture technique. An adult sheep was used as a donor of acellularized matrix. The thoracic aorta was harvested and processed by a multi-step decellularizing technique to remove the original cells and preserve the elastic and collagen fibers. The cultured smooth muscle cells and endothelial cells were then seeded to the acellularized matrix and incubated in vitro for another 2 weeks. The cell seeded graft was then transplanted to the cell-donated piglet to substitute part of the native pulmonary artery. Results： The cultured cells from piglet were characterized as endothelial cells by the presence of specific antigens vWF and CD31, and smooth muscle cells by the presence of specific antigen a-actin on the cell surface respectively with immunohistochemical technique. After decellularizing processing for the thoracic aorta from sheep, all the cellular components were extracted and elastic and collagen fibers kept their original morphology and structure. The maximal load of acellular matrix was decreased and 20% lower than that of untreated thoracic aorta, but the maximal tensions between them were not different statistically and they had similar load-tension curves. Three months after transplantation, the animal was sacrificed and the graft was removed for observation. The results showed that the inner surfaces of the graft were smooth, without thrombosis and calcification. Under microscopy, a great number of growing cells could be seen and elastic and collagen fibers were abundant. Conclusion： Cultured self-derived endothelial and smooth muscle cells could be used as seeding cells and heterogeneous acellularized matrix could be used as scaffold in constructing tissue-engineered graft.
