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D Keene

Publications and source records attributed to D Keene.

22 records · Page 2Linked to original sources
PubMed1985

Use of a child behavior checklist in the psychosocial assessment of children with epilepsy.

Children with epilepsy are faced with many of the same psychosocial stressors as other chronically ill children, and a proper assessment is vital. The purpose of this study was to determine whether the Child Behavior Checklist of Achenbach and Edelbrock could be used as a practical and objective tool for evaluating the psychosocial needs of children with epilepsy. Thirty-eight children were randomly selected from the Neurology outpatient clinic at the Children's Hospital of Eastern Ontario. Questionnaires were completed by the mothers during their waiting period. Results demonstrated the highest risk of maladjustment was within social functioning. As children reach adolescence, adjustment problems are mostly related to school. Although as a group, our sample did not differ from norms for behavior problems, there was evidence to suggest behavioral maladjustment for individual children. The checklist appears to be a good screening tool for maladjustment that could be included as part of the pediatrician's comprehensive assessment of children with epilepsy.

Adolescent↗
PubMed1984

Studies on the spectrin-like protein from the intestinal brush border, TW 260/240, and characterization of its interaction with the cytoskeleton and actin.

The terminal web of the intestinal brush border contains a spectrin-like protein, TW 260/240 (Glenney, J. R., Jr., P. Glenney, M. Osborne, and K. Weber, 1982, Cell, 28:843-854.) that interconnects the "rootlet" ends of microvillar filament bundles in the terminal web (Hirokawa, N., R. E. Cheng, and M. Willard, 1983, Cell, 32:953-965; Glenney J. R., P. Glenney, and K. Weber, 1983, J. Cell Biol., 96:1491-1496). We have investigated further the structural properties of TW 260/240 and the interaction of this protein with actin. Salt extraction of TW 260/240 from isolated brush borders results in a loss of terminal web cross-linkers primarily from the apical zone directly beneath the plasma membrane. Morphological studies on purified TW 260/240 using the rotary shadowing technique confirm earlier results that this protein is spectrin-like and is in the tetrameric state in buffers of low ionic strength. However, examination of TW 260/240 tetramers by negative staining revealed a molecule much straighter and more uniform in diameter than rotary-shadowed molecules. At salt concentrations at (150 mM KCl) and above (300 mM KCl) the physiological range, we observed a partial dissociation of tetramers into dimers that occurred at both 0 degree and 37 degrees C. We also observed (in the presence of 75 mM KCl) a concentration-dependent self-association of TW 260/240 into sedimentable aggregates. We have studied the interaction of TW 260/240 with actin using techniques of co-sedimentation, viscometry, and both light and electron microscopy. We observed that TW 260/240 can bind and cross-link actin filaments and that this interaction is salt- and pH-dependent. Under optimum conditions (25-75 mM KCl, at pH 7.0) TW 260/240 cross-linked F-actin into long, large-diameter bundles. The filaments within these bundles were tightly packed but loosely ordered. At higher pH (7.5) such bundles were not observed, although binding and cross-linking were detectable by co-sedimentation and viscometry. At higher salt (greater than 150 mM KCl), the binding of TW 260/240 to actin was inhibited. The presence of skeletal muscle tropomyosin had no significant effect on the salt-dependent binding of TW 260/240 to F-actin.

Actins↗
PubMed1981

Supercoiled mitochondrial DNAs from plant tissue culture cells.

Supercoiled mitochondrial DNA (mtDNA) has been isolated in preparative amounts from five different plant species and compared on agarose gels. The gels reveal considerable mtDNA size heterogeneity within each species as well as substantial differences in the range and frequency of the mtDNA size classes among the different plants. The two lowest size classes of three of the plants have been extracted and their molecular weights determined. Comparison of two N. tabacum W38 culture lines has revealed significant differences in their mtDNA size classes. However, despite the totally different supercoil patterns, these two lines have almost identical restriction digests. The availability of preparative amounts of separated mtDNA size classes will make it possible to carry out a detailed analysis of plant mitochondrial genomes.

Cell Line↗