Predators can impact prey via predation or risk effects, which can initiate trophic cascades. Given widespread population declines of apex predators, understanding and predicting the associated ecological consequences is a priority. When predation risk is relatively unpredictable or uncontrollable by prey, the loss of predators is hypothesized to release prey from stress; however, there are few tests of this hypothesis in the wild.
View Article and Find Full Text PDFThe phase III RV144 human immunodeficiency virus (HIV) vaccine trial conducted in Thailand remains the only study to show efficacy in decreasing the HIV acquisition risk. In Thailand, circulating recombinant forms of HIV clade A/E (CRF01_AE) predominate; in such viruses, originates from clade E (HIV-E). We constructed a simian-human immunodeficiency virus (SHIV) chimera carrying isolated from an RV144 placebo recipient in the SHIV-1157ipd3N4 backbone.
View Article and Find Full Text PDFPigment Cell Res
October 2002
Aloesin, [2-acetonyl-8-beta-d-glucopyranosyl-7-hydroxy-5-methylchromone], a compound isolated from the Aloe plant, is shown in these studies to modulate melanogenesis via competitive inhibition of tyrosinase. Aloesin inhibits purified tyrosinase enzyme and specifically inhibits melanin production in vitro. Enzyme kinetics studies using normal human melanocyte cell lysates and cell-based melanin production demonstrated that aloesin is a competitive inhibitor of tyrosinase from mushroom, human and murine sources.
View Article and Find Full Text PDFJ Chromatogr B Biomed Sci Appl
January 2001
The measurement of androgen steroids has been utilized as a clinical indicator of adrenal function, androgen abuse, and as a prediction of general health or biological aging. An improved high-performance liquid chromatography-ion trap mass spectroscopic method with sonic spray ionization (SSI) technology for the quantification of individual urinary 17-ketosteroid sulfates and glucuronides was developed and validated. Sample preparation was simplified using a C18 cartridge followed by direct injection onto a reversed-phase HPLC column.
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