The importance of word-initial phonology: error patterns in prolonged naming efforts by aphasic patients.

Whether multiple conscious efforts at word search bring a subject closer to an elusive word and to eventual successful retrieval remains a subject of debate. Previous work with normal participants has shown that multiple attempts eventuating in correct retrieval are not usually associated with a systematic progression toward target word phonology in the intervening attempts. In this study we analyzed the naming errors produced by 30 aphasic patients who had received the Boston Naming Test. The analyses were designed to elucidate the characteristics of responses that led to eventual success. Our data showed that among aphasics, as with normal subjects, the presence of target-initial phonology in the subject's first response was the most important predictor of correct retrieval. Moreover, progression towards target phonology in the course of multiple attempts was unrelated to eventual correct retrieval.

Accurate and efficient cleavage of the human insulin proreceptor by the human proprotein-processing protease furin. Characterization and kinetic parameters using the purified, secreted soluble protease expressed by a recombinant baculovirus.

Maturation of the insulin proreceptor in a late Golgi compartment requires cleavage at an Arg-Lys-Arg-Arg processing site, suggesting involvement of furin, a transmembrane serine protease of the Kex2 family of processing enzymes. A genetically engineered secreted, soluble form of human furin (ss-furin), expressed by infection of insect cells with a recombinant baculovirus, was purified to near homogeneity. ss-Furin exhibited rapid and efficient cleavage of both isoforms of the human insulin proreceptor in solubilized extracts of cultured mammalian cells expressing preproreceptor cDNA. Proreceptor cleavage occurred at the physiological processing site as judged by the effects of mutations in this site on cleavage by purified ss-furin. Moreover, purified ss-furin exhibited specificity for proreceptor cleavage identical to that of the endogenous insulin proreceptor-processing enzyme. Furin thus displays the properties expected of an insulin proreceptor-processing enzyme in that it (i) cleaves the proreceptor efficiently and at the correct site; (ii) exhibits the same specificity in processing variant proreceptors as the endogenous enzyme; (iii) appears to be localized in the correct secretory compartment; and (iv) has the same broad pattern of tissue distribution as the insulin proreceptor.

Mothers' lexicon of internal state words in speech to children with Down syndrome and to nonhandicapped children at mealtime.

This study examines internal state words in mothers' speech to children with Down syndrome, and the relation between the use of internal state words and the children's levels of social-adaptive, communicative, and linguistic functioning. Results indicate qualitative differences in mothers' use of internal state words to children with children Down syndrome, compared with a sample of maternal speech to nonhandicapped children who were matched on the Vineland scales for their level of adaptive functioning. Differences include use of fewer internal state words overall to children with Down syndrome, and different kinds of internal state words: more words referring to physiological states, and fewer words referring either to affect or to cognition. In general, child Mean Length of Utterance (MLU) was associated with the pattern of inner state words used by mothers, whereas no associations were found between children's social-adaptive competence and maternal input. Even when controlling for child MLU, there were, however, some qualitative differences in the inner state lexicons used to children with Down syndrome. Results suggest that speech to children with Down syndrome that is calibrated to their MLU may underestimate their competence in domains other than grammar.

Narrative strategies of aphasic and normal-speaking subjects.

A Picture Story Test for eliciting narrative speech was administered to five patients in each of the subgroups of Broca's and Wernicke's aphasic subjects and matched controls. While Wernicke's subjects and normal-speaking subjects did not differ significantly total output, the proportion of significant target lexemes was four times as great for normal-speaking subjects as for Wernicke's aphasic subjects. Broca's aphasic subjects, in spite of their telegraphic output, also had a smaller proportion of target lexemes than normal speakers. The proportion of nouns to verbs was elevated in the speech of Broca's asphasic subjects and depressed in the speech of Wernicke's aphasic subjects. Grammatical complexity was reduced in Wernicke's aphasic subjects, who used simple concatenation much more often than normal-speaking subjects. The Picture Story Test is suggeted as a clinically useful technique.