为明确杨树对氮沉降和增水的响应机制,采用2因素(氮和水添加)随机区组设计,设置4个施氮水平(0、5、10和15 g N·m^(-2)·a^(-1))以及3个水分水平(自然降水、自然降水增加50%和增加100%),测定杨树幼苗不同器官(叶、枝、茎、粗根...为明确杨树对氮沉降和增水的响应机制,采用2因素(氮和水添加)随机区组设计,设置4个施氮水平(0、5、10和15 g N·m^(-2)·a^(-1))以及3个水分水平(自然降水、自然降水增加50%和增加100%),测定杨树幼苗不同器官(叶、枝、茎、粗根和细根)中C、N、P含量,分析各器官元素间的关系。结果表明:随施氮量增加,粗根和细根N含量和N∶P及细根P含量增加,粗根和细根C∶N及细根C∶P下降。随降水增加,叶和细根C含量下降,茎和粗根C含量保持稳定,粗根N∶P上升。施氮与增水对杨树幼苗化学计量具有交互作用。自然降水下,随施氮量增加,枝、茎、粗根和细根C含量、叶、枝和茎N含量和P含量变化不显著;增水50%处理下,随施氮量增加,叶、枝和细根C含量、各器官N含量及叶、茎和粗根P含量增加;增水100%处理下,随施氮量增加,叶、茎和粗根C和P含量变化不显著。相同元素(C、N、P)在杨树幼苗不同器官中具有较高的正相关关系,N与P含量在叶和细根中呈显著正相关。因此,自然降水下,施氮只影响杨树幼苗地下部分N、P分配;降水增加50%下,施氮促进了各器官C、N、P分配;而降水增加100%减弱了氮添加的影响。展开更多
Since 1963,when the first human liver transplantation(LT)was performed by Thomas Starzl,the world has witnessed 50 years of development in surgical techniques,immunosuppression,organ allocation,donor selection,and the...Since 1963,when the first human liver transplantation(LT)was performed by Thomas Starzl,the world has witnessed 50 years of development in surgical techniques,immunosuppression,organ allocation,donor selection,and the indications and contraindications for LT.This has led to the mainstream,wellestablished procedure that has saved innumerable lives worldwide.Today,there are hundreds of liver transplant centres in over 80 countries.This review aims to describe the main aspects of LT regarding the progressive changes that have occurred over the years.We herein review historical aspects since the first experimental studies and the first attempts at human transplantation.We also provide an overview of immunosuppressive agents and their potential side effects,the evolution of the indications and contraindications of LT,the evolution of survival according to different time periods,and the evolution of methods of organ allocation.展开更多
Liver transplant for hepatitis B virus(HBV) currently yields excellent outcomes: it allows to rescue patients with an HBV-related advanced liver disease, resulting in a demographical modification of the waiting list f...Liver transplant for hepatitis B virus(HBV) currently yields excellent outcomes: it allows to rescue patients with an HBV-related advanced liver disease, resulting in a demographical modification of the waiting list for liver transplant. In an age of patient-tailored treatments, in liver transplantation as well the aim is to offer the best suitable graft to the patient who can benefit from it, also expanding the criteria for organ acceptance and allocation. With the intent of developing strategies to increase the donor pool, we set-up a multicenter study involving 3 Liver Transplant Centers in Italy: patients undergoing liver transplantation between March 03, 2004, and May 21, 2010, were retrospectively evaluated. 1408 patients underwent liver transplantation during the study period, 28(2%) received the graft from hepatitis B surface antigen positive(HBs Ag)-positive deceased donors. The average follow-up after liver transplantation was 63.7 mo [range: 0.1-119.4; SD ± 35.8]. None Primary nonfunction, re-liver transplantation, early or late hepatic artery thrombosis occurred. The 1-, 3-and 5-year graft and patient survival resulted of 85.7%, 82.1%, 78.4%. Our results suggest that the use of HBs Agpositive donors liver grafts is feasible, since HBV can be controlled without affecting graft stability. However, the selection of grafts and the postoperative antiviral therapy should be managed appropriately.展开更多
文摘为明确杨树对氮沉降和增水的响应机制,采用2因素(氮和水添加)随机区组设计,设置4个施氮水平(0、5、10和15 g N·m^(-2)·a^(-1))以及3个水分水平(自然降水、自然降水增加50%和增加100%),测定杨树幼苗不同器官(叶、枝、茎、粗根和细根)中C、N、P含量,分析各器官元素间的关系。结果表明:随施氮量增加,粗根和细根N含量和N∶P及细根P含量增加,粗根和细根C∶N及细根C∶P下降。随降水增加,叶和细根C含量下降,茎和粗根C含量保持稳定,粗根N∶P上升。施氮与增水对杨树幼苗化学计量具有交互作用。自然降水下,随施氮量增加,枝、茎、粗根和细根C含量、叶、枝和茎N含量和P含量变化不显著;增水50%处理下,随施氮量增加,叶、枝和细根C含量、各器官N含量及叶、茎和粗根P含量增加;增水100%处理下,随施氮量增加,叶、茎和粗根C和P含量变化不显著。相同元素(C、N、P)在杨树幼苗不同器官中具有较高的正相关关系,N与P含量在叶和细根中呈显著正相关。因此,自然降水下,施氮只影响杨树幼苗地下部分N、P分配;降水增加50%下,施氮促进了各器官C、N、P分配;而降水增加100%减弱了氮添加的影响。
文摘Since 1963,when the first human liver transplantation(LT)was performed by Thomas Starzl,the world has witnessed 50 years of development in surgical techniques,immunosuppression,organ allocation,donor selection,and the indications and contraindications for LT.This has led to the mainstream,wellestablished procedure that has saved innumerable lives worldwide.Today,there are hundreds of liver transplant centres in over 80 countries.This review aims to describe the main aspects of LT regarding the progressive changes that have occurred over the years.We herein review historical aspects since the first experimental studies and the first attempts at human transplantation.We also provide an overview of immunosuppressive agents and their potential side effects,the evolution of the indications and contraindications of LT,the evolution of survival according to different time periods,and the evolution of methods of organ allocation.
文摘Liver transplant for hepatitis B virus(HBV) currently yields excellent outcomes: it allows to rescue patients with an HBV-related advanced liver disease, resulting in a demographical modification of the waiting list for liver transplant. In an age of patient-tailored treatments, in liver transplantation as well the aim is to offer the best suitable graft to the patient who can benefit from it, also expanding the criteria for organ acceptance and allocation. With the intent of developing strategies to increase the donor pool, we set-up a multicenter study involving 3 Liver Transplant Centers in Italy: patients undergoing liver transplantation between March 03, 2004, and May 21, 2010, were retrospectively evaluated. 1408 patients underwent liver transplantation during the study period, 28(2%) received the graft from hepatitis B surface antigen positive(HBs Ag)-positive deceased donors. The average follow-up after liver transplantation was 63.7 mo [range: 0.1-119.4; SD ± 35.8]. None Primary nonfunction, re-liver transplantation, early or late hepatic artery thrombosis occurred. The 1-, 3-and 5-year graft and patient survival resulted of 85.7%, 82.1%, 78.4%. Our results suggest that the use of HBs Agpositive donors liver grafts is feasible, since HBV can be controlled without affecting graft stability. However, the selection of grafts and the postoperative antiviral therapy should be managed appropriately.
