Diapause as escape strategy to exposure to toxicants: response of Brachionus calyciforus to arsenic

Invertebrate organisms commonly respond to environmental fluctuation by entering diapause. Production of diapause in monogonont rotifers involves a previous switch from asexual to partial sexual reproduction. Although zooplankton have been used in ecotoxicological assays, often their true vulnerability to toxicants is underestimated by not incorporating the sexual phase. We experimentally analyzed traits involved in sexual reproduction and diapause in the cyclically parthenogenetic freshwater rotifer, Brachionus calyciflorus, exposed to arsenic, a metalloid naturally found in high concentrations in desert zones, focusing on the effectiveness of diapause as an escape response in the face of an adverse condition. Addition of sublethal concentrations of arsenic modified the pattern of diapause observed in the rotifer: investment in diapause with arsenic addition peaked earlier and higher than in non-toxicant conditions, which suggests that sexual investment could be enhanced in highly stressed environmental conditions by increased responsiveness to stimulation. Nevertheless, eggs produced in large amount with arsenic, were mostly low quality, and healthy-looking eggs had lower hatching success, therefore it is unclear whether this pattern is optimum in an environment with arsenic, or if rather arsenic presence in water bodies disturbs the optimal allocation of offspring entering diapause. We observed high accumulation of arsenic in organisms exposed to constant concentration after several generations, which suggests that arsenic may be accumulated transgenerationally. The sexual phase in rotifers may be more sensitive to environmental conditions than the asexual one, therefore diapause attributes should be considered in ecotoxicological assessment because of its ecological and evolutionary implications on lakes biodiversity

Violência contra a criança: indicadores dermatológicos e diagnósticos diferenciais Child abuse: skin markers and differential diagnosis

As denúncias de abuso contra a criança têm sido frequentes e configuram grave problema de saúde pública. O tema é desconfortável para muitos médicos, seja pelo treinamento insuficiente, seja pelo desconhecimento das dimensões do problema. Uma das formas mais comuns de violência contra a criança é o abuso físico. Como órgão mais exposto e extenso, a pele é o alvo mais sujeito aos maustratos. Equimoses e queimaduras são os sinais mais visíveis. Médicos (pediatras, clínicos-gerais e dermatologistas) costumam ser os primeiros profissionais a observar e reconhecer sinais de lesões não acidentais ou intencionais. Os dermatologistas podem auxiliar na distinção entre lesões traumáticas intencionais, acidentais e doenças cutâneas que mimetizam maus-tratos<br>Reports of child abuse have increased significantly. The matter makes most physicians uncomfortable for two reasons: a) Little guidance or no training in recognizing the problem; b - Not understanding its true dimension. The most common form of child violence is physical abuse. The skin is the largest and frequently the most traumatized organ. Bruises and burns are the most visible signs. Physicians (pediatricians, general practitioners and dermatologists) are the first professionals to observe and recognize the signs of intentional injury. Dermatologists particularly, can help distinguish intentional injury from accidental, or from skin diseases that mimic maltreatmen