The value of daily platelet counts for predicting dengue shock syndrome: Results from a prospective observational study of 2301 Vietnamese children with dengue.

Background Dengue is the most important mosquito-borne viral infection to affect humans. Although it usually manifests as a self-limited febrile illness, complications may occur as the fever subsides. A systemic vascular leak syndrome that sometimes progresses to life-threatening hypovolaemic shock is the most serious complication seen in children, typically accompanied by haemoconcentration and thrombocytopenia. Robust evidence on risk factors, especially features present early in the illness course, for progression to dengue shock syndrome (DSS) is lacking. Moreover, the potential value of incorporating serial haematocrit and platelet measurements in prediction models has never been assessed. Methodology/Principal findings We analyzed data from a prospective observational study of Vietnamese children aged 5±15 years admitted with clinically suspected dengue to the Hospital for Tropical Diseases in Ho Chi Minh City between 2001 and 2009. The analysis population comprised all children with laboratory-confirmed dengue enrolled between days 1±4 of illness. Logistic regression was the main statistical model for all univariate and multivariable analyses. The prognostic value of daily haematocrit levels and platelet counts were assessed using graphs and separate regression models fitted on each day of illness. Among the 2301 children included in the analysis, 143 (6%) progressed to DSS. Significant baseline risk factors for DSS included a history of vomiting, higher temperature, a palpable liver, and a lower platelet count. Prediction models that included serial daily platelet counts demonstrated better ability to discriminate patients who developed DSS from others, than models based on enrolment information only. However inclusion of daily haematocrit values did not improve prediction of DSS. Conclusions/Significance Daily monitoring of platelet counts is important to help identify patients at high risk of DSS. Development of dynamic prediction models that incorporate signs, symptoms, and daily laboratory measurements, could improve DSS prediction and thereby reduce the burden on health services in endemic areas.</p

Antioxidant and cytotoxic activity of lichens collected from Bidoup Nui Ba National Park, Vietnam

[[abstract]]Lichens were some of the earliest colonizers of terrestrial habitats on Earth. They represent a unique symbiont between fungi (mycobionts) and algae and/or cyanobacteria (photobionts). Lichens have been used as a cure for diabetes, coughs, pulmonary tuberculosis, wound healing, and dermatological diseases. The aim of this study is to investigate the in vitro antioxidant and cytotoxic activities of methanol lichen extracts. Fourteen lichen species from Bidoup Nui Ba National Park were identified according to their morphology and anatomical and chemical characteristics. The antioxidant activity of the methanol lichen extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay. The results showed that, of the lichens tested, L5 had the highest free radical activity with 50% inhibitory concentration (IC50) of 59.9 ± 4.65 mg mL−1. The methanol extract of L5 also showed the highest total flavonoid and polyphenol contents. In a cytotoxic assay, it was observed that the methanol extract of U38.1 exhibited high cytotoxic effect against MCF-7 cells, with IC50 of 34.27 ± 1.25 mg mL−1. The tested lichen extracts were also found to have slight cytotoxic effect on fibroblasts at screening concentration of 100 µg mL−1. All of the extracts were found to possess different cytotoxic activities against MO-91 cells, with IC50 values ranging from 10.50 ± 1.56 to over 50 mg mL−1. All of the extracts except U38.1 induced normal peripheral blood mononuclear cell (PBMC) proliferation, especially after 48 h of treatment at 25 µg/mL.[[notice]]補正完