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Biomedical subjects

N Richman

Publications and source records attributed to N Richman.

36 records · Page 2Linked to original sources
PubMed1978

Behavior, language, and development in three-year-old children.

An epidemiological study of 3-year-old children showed there to be a marked association between behavior problems and language delay. Behavior problems were present in 14% of a random sample of 705 children, whereas 59% of 22 children with language delay had such problems. Data obtained from a battery of developmental tests were analyzed to examine the differences between children with behavior problems, matched controls, and children with language delay. It was found that children with behavior problems scored significantly lower on these tests, particularly those concerned with language. There were no significant differences in test scores between children with language delay only and those with combined behavior problems and language delay.

Child Behavior↗
PubMed1977

Behaviour problems in pre-school children: family and social factors.

In a group of 99 three-year-old children with behaviour problems identified in an epidemiological survey, family and social factors were compared with those in a group of controls. Behaviour problems were significantly associated with a strained marital relationship between parents, with social stresses and with type of housing. There was a high rate of maternal depression in both problem and control groups. The interaction between a behaviour problem in a young child, maternal mental health and social factors is discussed.

Child Behavior Disorders↗
PubMed1976

The prevalence of language delay in a population of three-year-old children and its association with general retardation.

Using a simple assessment of language and a behaviour screening questionnaire, a one-in-four random sample of a total population of three-year-olds was screened for the presence of language delay and behaviour problems. A full psycho-developmental assessment was carried out in children with suspected language delay or a behaviour problem, and in a group of control children, and the sensitivity and specificity of the language screening-test was examined. The results showed the importance of investigating language delay in relation to nonverbal abilities. Of those children with a language age less than two-thirds of their chronological age, 37 per cent also had similarly delayed non-verbal mental abilities. 50 per cent of the children with a language age of less than 30 months were generally retarded in their non-verbal abilities. The estimated prevalence of delayed language development is 31 per 1000, of specific language delay 5-7per 1000, and of severe retardation 4-2 per 1000. Boys were most likely than girls to have language and general developmental delay.

Age Factors↗
PubMed1975

Some characteristics of and structural requirements for the interaction of 24,25-dihydrofusidic acid with ribosome - elongation factor g Complexes.

Fusidic acid inhibits polypeptide chain elongation by binding to the ribosome - elongation factor-G - GDP complex and thereby preventing its dissociation. The experiments reported here quantitate the interaction of the antibiotic [3H]-24,25-dihydrofusidic acid, an active analog of fusidic acid, with the ribosome - elongation factor-G - GDP comples. All components of the complex are essential for [3H]-24,25-dihydrofusidic acid binding. The stoichiometry of the interaction is ca. 1:1, and the Ka apparent, as determined by equilibrium dialysis, is 2.6 times 10-6 M-minus 1. It is further shown that GTP and GDP are equally effective in forming complexes to which the antibiotic may bind, whereas GMP and beta,gamma-methyleneguanosine triphosphate will not form complexes to which the antibiotic may bind. In order to examine the structural basis of the mode of antibiotic action shown by fusidic acid, we have considered two activities of 21 structural analogs of this antibiotic: ability to bind to the aforementioned ternary complex and ability to stabilize this complex. The comparative binding capability of the analogs were extablished through competition experiments with [3H]-24,25-dihydrofusidic acid. The data obtained from these experiments can be summarized as follows. (1) The C17-20 double bond of fusidic acid appears to be critical for both binding and complex stabilization activities. (2) A carboxyl group in the vicinity of the C20 carbon is also essential for both activities. (3) Modifications of other functional groups in the molecule can lead to significantly decreased stabilization of the ternary ribosome complex and/or ability to compete with [3H]-24,25-dihydrofusidic acid for binding to the complex, but do not demonstrate absolute structural requirements for either activity.

Binding Sites↗
PubMed1972

Ribosomes cannot interact simultaneously with elongation factors EF Tu and EF G.

Prior binding of EF G and GDP to 70S ribosomes from Escherichia coli prevents the subsequent binding of aminoacyl-tRNA, mediated by EF Tu. However, the interaction of EF Tu.GTP.aminoacyl-tRNA with the 30S subunit, which results in aminoacyl-tRNA binding without GTP hydrolysis, appears to be unaffected by EF G, GDP, and fusidic acid. We conclude that elongation factors Tu and G cannot interact simultaneously with the ribosome. The simplest interpretation of these and earlier data is that EF G and EF Tu interact with the same, or overlapping, 50S ribosomal sites in the course of GTP hydrolysis associated with translocation and aminoacyl-tRNA binding, respectively. In any event, these factors must alternate in binding to the ribosome in the course of each elongation cycle.

Escherichia coli↗
PubMedDate not supplied

Outcome of behaviour problems in the preschool setting.

A sample of 2-4-year-old children attending four local authority day nurseries and 10 nursery school classes was screened for the presence of behaviour problems using the Preschool Behaviour Checklist which is completed by nursery staff. The screening was repeated 20 months later on 79% (300) and 66% (109) of the original nursery school and day nursery samples respectively. Initially, 11% of the former and 35% of the latter were rated as showing significant difficulties. Problems persisted in 10% of the original nursery school and 58% of the original day nursery children. The appearance of new cases did not differ significantly between the two groups. Factors associated with persistence and with development of problems are discussed.

Child Behavior Disorders↗