In situ short-term responses of Amazonian understory plants to elevated CO2.

The response of plants to increasing atmospheric CO2 depends on the ecological context where the plants are found. Several experiments with elevated CO2 (eCO2) have been done worldwide, but the Amazonian forest understory has been neglected. As the central Amazon is limited by light and phosphorus, understanding how understory responds to eCO2 is important for foreseeing how the forest will function in the future. In the understory of a natural forest in the Central Amazon, we installed four open-top chambers as control replicates and another four under eCO2 (+250 ppm above ambient levels). Under eCO2, we observed increases in carbon assimilation rate (67%), maximum electron transport rate (19%), quantum yield (56%), and water use efficiency (78%). We also detected an increase in leaf area (51%) and stem diameter increment (65%). Central Amazon understory responded positively to eCO2 by increasing their ability to capture and use light and the extra primary productivity was allocated to supporting more leaf and conducting tissues. The increment in leaf area while maintaining transpiration rates suggests that the understory will increase its contribution to evapotranspiration. Therefore, this forest might be less resistant in the future to extreme drought, as no reduction in transpiration rates were detected.

Perioperative Anaphylaxis to Chlorhexidine during Surgery and Septoplasty.

Chlorhexidine is an antiseptic and disinfectant used in surgical and clinical practice since 1954 and is available in aqueous or alcoholic solutions 0.5%-4.0% and has a broad-spectrum activity. Despite their widespread use, allergic reactions with chlorhexidine are rarely reported. We describe a case of anaphylaxis with chlorhexidine during a septoplasty, turbinectomy, and maxillary sinusectomy. The patient presented with periorbital edema, hives, hypotension, and wheezing. Immediately after the diagnosis of anaphylaxis promethazine, hydrocortisone, and epinephrine were administered with immediate clinical improvement. This case highlights the importance of assessing whether there is a previous clinical history of hypersensitivity to chlorhexidine in patients who will undergo surgical procedures.