RESUMO
The relation between abnormal stereotyped behaviors and abnormal focused affections (i.e., abnormally consistent preferences for specific objects, symbols, and/or physical locations) was examined in 20 children with developmental disabilities. Results indicated that (a) all children who exhibited abnormal focused affections exhibited stereotypies; (b) abnormal focused affections could be studied reliably in individuals with developmental disabilities through the use of direct time-sampling observations, naturalistic observations, and informant reports; and (c) developmental age was significantly related to the frequency of (and the number of different) stereotyped behaviors and the frequency of nonstereotyped (i.e., developmentally appropriate) behaviors exhibited across the sample. Results also provide preliminary support for the notion of a general stereotyped behavioral repertoire in individuals with developmental disabilities.
Assuntos
Afeto , Deficiência Intelectual , Comportamento Estereotipado , Adolescente , Fatores Etários , Criança , Feminino , Humanos , MasculinoRESUMO
A number of transition metal ions with a wide distribution in biological systems, e.g., Cu2+, Co2+ and Zn2+, are shown to affect markedly the chemical properties of melanins formed by the tyrosinase-catalysed oxidation of dopa. Acid decarboxylation and permanganate degradation provide evidence that melanins prepared in the presence of metal ions contain a high content of carboxyl groups arising from the incorporation of 5,6-dihydroxyindole-2-carboxylic acid (DICA) into the pigment polymer. Naturally occurring melanins from cephalopod ink and B16 mouse melanoma were found to be much more similar to melanins prepared in the presence of metal ions than to standard melanins prepared in the absence of metal ions. These results suggest that the presence of carboxylated indole units in natural melanins is probably due to the intervention in the biochemical pathway of metal ions which, as recently shown, catalyse the formation of DICA versus 5,6-dihydroxyindole in the rearrangement of dopachrome.
Assuntos
Catecol Oxidase/metabolismo , Melaninas/biossíntese , Metais/farmacologia , Monofenol Mono-Oxigenase/metabolismo , Animais , Cobalto/farmacologia , Cobre/farmacologia , Levodopa/metabolismo , Melaninas/isolamento & purificação , Moluscos , Níquel/farmacologia , Octopodiformes , Zinco/farmacologiaRESUMO
13C-NMR spectroscopy of pheomelanin biopolymers, prepared from isotopically enriched precursors, has been developed as a tool for structure elucidation of melanins. By employing large pulse-widths and short cycle time, only the signals originating from labeled carbons are observed in the high-resolution spectra of these polymers.
