RESUMO
Worldwide coffee production is threatened by climate change, which highlights the importance of heat tolerance studies. Here we tested the hypothesis that photosynthetic heat tolerance in coffee varieties changes according to acclimation to distinct light conditions. Furthermore, we tested if heat tolerance is associated with the habitat of origin of the coffee species. We evaluated heat tolerance using chlorophyll fluorescence in varieties of Coffea arabica (Mundo Novo and Catuai Amarelo) and C. canephora (Conilon) grown in a common garden under two conditions: high (HS) and low (LS) sunlight. Leaf traits associated with leaf cooling were evaluated in plants grown in LS and HS and associations of heat tolerance with these traits were determined. The varieties tested had high photosynthetic heat tolerance, with temperatures above 54 °C leading to a 50% reduction in Fv /Fm (T50 ). The heat tolerance of each Coffea variety was unaffected by growth in distinct light conditions. Leaves of plants grown in LS were larger and had a lower fraction of the leaf area occupied by stomata (nast ). Heat tolerance was positively associated with leaf size and negatively with nast . C. canephora exhibited higher heat tolerance than C. arabica. The limited plasticity of heat tolerance in response to acclimation under distinct light conditions contradicts the prediction that plants acclimated to HS would have higher photosynthetic heat tolerance than those acclimated to LS. Our results on heat tolerance among Coffea species/varieties in HS and LS indicate the possibility of selection of varieties for better acclimation to ongoing climate changes.
Assuntos
Coffea , Termotolerância , Coffea/fisiologia , Café , Fotossíntese/fisiologia , Aclimatação/fisiologiaRESUMO
UNLABELLED: Ex situ hepatic transection (ESHT) has allowed transplantation of younger and smaller patients than whole liver grafts. Liver transection is a technical challenge due to the prolonged back table time, possible graft lesions, and increased surgical bleeding from the cut surface. We compare the outcomes of whole versus transected liver grafts in pediatric liver transplantation. METHODS: We retrospectively studied 41 pediatric patients who underwent 42 consecutive liver transplants (1 retransplant) from cadaveric donors. The study included all patients <18 years old who were transplanted at our institution from December 2001 to September 2009. Patients were distributed into 2 groups: whole organ (WO; n = 20) and transected liver grafts (TLG; n = 21). The ESHT grafts included 17 splits and 5 reduced size livers. We evaluated the age, weight, blood component transfusions, 1-year survival, laboratory tests at 2nd and 7th days postoperatively, surgical complications, reoperations, rejection episodes, cold ischemia time, biliary reconstruction type, and donor laboratory tests. Data were analyzed using Fisher and Student's t-tests. RESULTS: The mean age was 115 months (range, 7 months to 17.6 years) in the WO group and 43.3 months (range, 5 months to 16.25 years) in the TLG group (P = .0003). Mean weight was 19.8 kg (range, 5.8-67) and 9.7 Kg (range, 5.2-57) in the WO and TLG groups, respectively (P = .0079). Red blood cell transfusion was higher in the TLG group (P = .0479). Laboratory tests showed no difference between the 2 groups considering hepatic lesions or function markers. One-year patient survivals were 90% and 85.8% among the WO and LTG, respectively (P = .588). The overall 1-year survival rate was 88.8%. CONCLUSION: ESHT allowed smaller and younger children to be transplanted. There was an increased necessity of red blood cell transfusions after hepatic transection. There was no impact on liver function or 1-year patient or graft survival after ESHT.
Assuntos
Transplante de Fígado/estatística & dados numéricos , Adolescente , Transfusão de Componentes Sanguíneos , Perda Sanguínea Cirúrgica , Cadáver , Criança , Pré-Escolar , Contagem de Eritrócitos , Vesícula Biliar/cirurgia , Rejeição de Enxerto/epidemiologia , Hematócrito , Hepatectomia , Humanos , Lactente , Período Intraoperatório , Testes de Função Hepática , Transplante de Fígado/imunologia , Transplante de Fígado/mortalidade , Contagem de Plaquetas , Período Pós-Operatório , Procedimentos de Cirurgia Plástica , Reoperação , Estudos Retrospectivos , Análise de Sobrevida , Doadores de TecidosRESUMO
O objetivo deste trabalho foi preparar, em condiçöes adequadas, o fármaco (DTPA) marcado com isótopo radioativo para estudos de cinrilografia renal. Além de avaliar a funçäo renal, este fármaco permite diagnosticar, precocemente, alteraçöes que indicam rejeiçäo de tecido, em casos de transplante de rins. Inicialmente, foram realizados experimentos com camundongos para investigar a distribuiçäo biológica do radiofármaco. Os resultados mostraram que, alguns minutos após a administraçäo, os rins apresentavam uma captaçäo de radioatividade. Estes dados e os resultados dos testes de esterilidade, apirogenicidade e pureza radioquímica confirmaram a qualidade do radiofármaco, permitindo o seu emprego em cintilografias de pacientes com comprometimento renal