Photosynthetic quantum efficiency in south‐eastern Amazonian trees may be already affected by climate change

Tropical forests are experiencing unprecedented high‐temperature conditions due to climate change that could limit their photosynthetic functions. We studied the high‐temperature sensitivity of photosynthesis in a rainforest site in southern Amazonia, where some of the highest temperatures and most rapid warming in the Tropics have been recorded. The quantum yield (F v /F m ) of photosystem II was measured in seven dominant tree species using leaf discs exposed to varying levels of heat stress. T 50 was calculated as the temperature at which F v /F m was half the maximum value. T 5 is defined as the breakpoint temperature, at which F v /F m decline was initiated. Leaf thermotolerance in the rapidly warming southern Amazonia was the highest recorded for forest tree species globally. T 50 and T 5 varied between species, with one mid‐storey species, Amaioua guianensis , exhibiting particularly high T 50 and T 5 values. While the T 50 values of the species sampled were several degrees above the maximum air temperatures experienced in southern Amazonia, the T 5 values of several species are now exceeded under present‐day maximum air temperatures

Pruritus: still a challenge Prurido: ainda um desafio

Pruritus is a symptom that may be associated with a wide array of diseases - skin diseases, systemic diseases or even those without a defined cause. According to its severity and evolution, it may compromise the patients' quality of life in a significant way. New therapeutic approaches, in which histamine release is not the main event, are being described for pruritus control. Therefore, taking into account the origin of the mediators of pruritus, we conducted a review of the available resources emphasizing that, although very important, anti-histamines are not the answer for every kind of pruritus.<br>Prurido é um sintoma que pode estar associado a uma gama ampla de patologias, sejam elas cutâneas, sistêmicas ou mesmo sem causa definida . Conforme sua intensidade e evolução pode comprometer de forma significativa a qualidade de vida dos pacientes. Novas abordagens terapêuticas estão sendo descritas para o controle do prurido, onde a liberação da histamina não é o fator principal. Assim, baseando-se na origem de seus mediadores, faz-se uma revisão desses recursos e ressalta-se que, embora de grande importância no arsenal terapêutico, os anti-histamínicos não são a panacéia para todos os tipos de prurido