Histological development of the epidermis was studied on skin samples from 169 infants (gestation 24–40 weeks, age up to 1 year). Gestation markedly influenced epidermal development. Before 30 weeks, the epidermis is thin, has few cell layers and a poorly formed stratum corneum, but by 34 weeks it has largely matured. Postnatal influence on epidermal development is marked in the preterm infant, so that histologically the epidermis of the most immature infant resembles that of a term infant by 2 weeks of age. These changes in histology exactly parallel the development of the barrier properties of newborn skin.
Susceptibility to geometrical visual illusions has been tested in a number of non-human animal species, providing important information about how these species perceive their environment. Considering their active role in human lives, visual illusion susceptibility was tested in domestic dogs (Canis familiaris). Using a two-choice simultaneous discrimination paradigm, eight dogs were trained to indicate which of two presented circles appeared largest. These circles were then embedded in three different illusory displays; a classical display of the Ebbinghaus-Titchener illusion; an illusory contour version of the Ebbinghaus-Titchener illusion; and the classical display of the Delboeuf illusion. Significant results were observed in both the classical and illusory contour versions of the Ebbinghaus-Titchener illusion, but not the Delboeuf illusion. However, this susceptibility was reversed from what is typically seen in humans and most mammals. Dogs consistently indicated that the target circle typically appearing larger in humans appeared smaller to them, and that the target circle typically appearing smaller in humans, appeared larger to them. We speculate that these results are best explained by assimilation theory rather than other visual cognitive theories explaining susceptibility to this illusion in humans. In this context, we argue that our findings appear to reflect higher-order conceptual processing in dogs that cannot be explained by accounts restricted to low-level mechanisms of early visual processing.
Aims-To examine a number of simple clinical features and investigations in children with a non-blanching rash to see which predict meningococcal infection. Methods-A total of 233 infants and children up to 15 years of age presenting with a non-blanching rash were studied over a period of 12 months. Clinical features and laboratory investigations were recorded at presentation. The ability of each to predict meningococcal infection was examined. Results-Eleven per cent had proven meningococcal infection. Children with meningococcal infection were more likely to be ill, pyrexial (>38.5°C), have purpura, and a capillary refill time of more than two seconds than non-meningococcal children. Five children with meningococcal disease had an axillary temperature below 37.5°C. No child with a rash confined to the distribution of the superior vena cava had meningococcal infection. Investigations were less helpful, although children with meningococcal infection were more likely to have an abnormal neutrophil count and a prolonged international normalised ratio. No child with a C reactive protein of less than 6 mg/l had meningococcal infection. Conclusions-Most children with meningococcal infection are ill, have a purpuric rash, a fever, and delayed capillary refill. They should be admitted to hospital and treated without delay. Children with a non-blanching rash confined to the distribution of the superior vena cava are very unlikely to have meningococcal infection. Measurement of C reactive protein may be helpful-no child with a normal value had meningococcal infection. Lack of fever at the time of assessment does not exclude meningococcal disease. (Arch Dis Child 2001;85:218-222)
The skin of the extremely preterm infant is structurally and functionally immature at birth, although there is rapid postnatal maturation. The consequences of this immaturity are a high transepidermal water loss (leading to hypothermia and difficulty in fluid balance) accidental percutaneous absorption and toxicity, and skin trauma (leading to infection). Neonatologists must be aware of these and take measures to limit them.Key words Preterm infant 9 Newborn skin 9 Transepidermal water loss 9 Skin damage Abbreviations TEWL transepidermal water loss
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