Development of reading proficiency in English by bilingual children and their monolingual peers

The semantic, syntactic, and graphophonic cueing techniques employed by 55 bilingual children and 39 monolingual peers when reading aloud in English were identified through miscue analysis. In contrast to earlier research in 1999 by Cline and Cozens no significant differences were found between the two groups on any of the techniques. Both bilingual and monolingual readers consistently used more graphophonic cues than syntactic or semantic cues but not significantly so. The authors discuss possible extraneous variables which may account in part for this unexpected result.

Exon 1 of the HD gene with an expanded CAG repeat is sufficient to cause a progressive neurological phenotype in transgenic mice

Huntington's disease (HD) is one of an increasing number of neurodegenerative disorders caused by a CAG/polyglutamine repeat expansion. Mice have been generated that are transgenic for the 5' end of the human HD gene carrying (CAG)115-(CAG)150 repeat expansions. In three lines, the transgene is ubiquitously expressed at both mRNA and protein level. Transgenic mice exhibit a progressive neurological phenotype that exhibits many of the features of HD, including choreiform-like movements, involuntary stereotypic movements, tremor, and epileptic seizures, as well as nonmovement disorder components. This transgenic model will greatly assist in an eventual understanding of the molecular pathology of HD and may open the way to the testing of intervention strategies.

Size and shape of rabbit skeletal muscle calsequestrin

Calsequestrin, a calcium-binding protein isolated from rabbit skeletal muscle sarcoplasmic reticulum, was subjected to physiochemical analysis using sodium dodecyl sulfate gel electrophoresis, gel filtration, sedimentation, viscosity, and circular dichroism techniques. The effects of sodium dodecyl sulfate, alkaline pH, guanidine hydrochloride, and calcium ions on the hydrodynamic properties of the protein were studied. Calsequestrin, in the absence of calcium, had a random coil conformation with an alpha-helical content of 11%. Calsequestrin bound 1.7 mg of sodium dodecyl sulfate per mg of protein resulting in an increase in the alpha-helical content to 20%. The protein was completely random coil in guanidine hydrochloride and had a molecular weight of 42,000 as determined by gel filtration in the presence of this denaturant. Sedimentation equilibrium studies showed that calsequestrin was not subjected to aggregation and had a molecular weight of 38,000. Calsequestrin had a low sedimentation coefficient (2.20 S), a high Stokes radius (45 A), and a high intrinsic viscosity (27.1 ml/g) that increased slightly to 32 ml/g in the presence of guanidine hydrochloride, all indicative of a highly extended structure. Similar studies, performed at pH 9.5, revealed that the protein was even more asymmetric at alkaline pH. Calsequestrin bound 50 mol of calcium ions per mol of protein with an affinity of 1 mM as determined by gel filtration. Calcium binding was accompanied by a change of the protein from a highly extended structure (Rs = 45 A) to a much more compact structure (Rs = 35 A).