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D Haggerty

Publications and source records attributed to D Haggerty.

6 recordsLinked to original sources
PubMed1990

Abnormalities of carbohydrate metabolism and of OCT gene function in the Rett syndrome.

The pathogenetic basis of the Rett syndrome (RS) is unknown: an X-linked dominant, male-lethal gene defect is thought likely. We present a girl with RS who has defects both of the urea cycle and of carbohydrate metabolism resulting in fasting hypoglycaemia, post-prandial hyperlactataemia and excess urinary orotic acid excretion after alanine load. Her sister has a similar clinical picture, but less marked metabolic anomalies. The mother of these sisters has abnormal urinary orotic acid excretion; she transmitted opposite ornithine carbomoyltransferase (OCT) alleles to the two girls. Another girl with RS has similar metabolic responses to fasting and to carbohydrate load. We conclude that RS may be an aetiologically homogeneous condition, but that it includes a variable pattern of metabolic anomalies, and that the gene defect is distinct from the OCT locus.

Adolescent↗
PubMed1980

The Escherichia coli L-arabinose operon: binding sites of the regulatory proteins and a mechanism of positive and negative regulation.

The locations of DNA binding by the proteins involved with positive and negative regulation of transcription initiation of the L-arabinose operon in Escherichia coli have been determined by the DNase I protection method. Two cyclic AMP receptor protein sites were found, at positions -78 to -107 and -121 to -146, an araC protein--arabinose binding site was found at position -40 to -78, and an araC protein-fucose binding site was found at position -106 to -144. These locations, combined with in vivo data on induction of the two divergently oriented arabinose promoters, suggest the following regulatory mechanism: induction of the araBAD operon occurs when cyclic AMP receptor protein, araC protein, and RNA polymerase are all present and able to bind to DNA. Negative regulation is accomplished by the repressing form of araC protein binding to a site in the regulatory region such that it stimultaneously blocks access of cyclic AMP receptor protein to two sites on the DNA, one site of which serves each of the two promoters. Thus, from a single operator site, the negative regulator represses the two outwardly oriented ara promoters. This regulatory mechanism explains the known positive and negative regulatory properties of the ara promoters.

AraC Transcription Factor↗
PubMedDate not supplied

Age-related differences in adults' macrospatial cognitive processes.

Young and elderly adults' performance was compared on the Landmark Selection Task, designed to assess perceptual selection, and the Scrambled Route Task, designed to assess temporospatial integration. Age-related performance decrements were found on both tasks. Subjects' scores on psychometric tests hypothesized as involving some of the same processes as these experimental tasks yielded positive correlations to measures of task performance. Unexpectedly, self-estimates of wayfinding and distance estimation skills were negatively correlated to experimental task performance for elderly adults. Results were discussed in the context of declines in the effectiveness of selective attention, which is considered critical to perceptual selection, and in the proficiency of working memory, which is considered central to temporospatial integration.

Adolescent↗