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Biomedical subjects

L E Wilson

Publications and source records attributed to L E Wilson.

27 records · Page 2Linked to original sources
PubMed1987

Line bisection by left-handed preschoolers: a phenomenon of symmetrical neglect.

When a normal dextral attempts to bisect a horizontal line placed across his/her midline, there is a tendency for the transection to be placed slightly to the left of true center, a tendency which may be a little more pronounced when the left hand is used. However, left-handed children at or younger than 5 years of age err substantially to the left with the left hand and to the right with the right hand. This symmetrical neglect of extents contralateral to the hand currently in use, which may possibly reflect relatively greater commissural immaturity in left-handers, was not seen in dextral children of comparable ages, whose performance closely followed adult patterns.

Child Development↗
PubMed1986

Isolation of a mutant LLC-PK1 cell line defective in hormonal responsiveness. A pleiotropic lesion in receptor function.

A mutant LLC-PK1 cell line, M18, was isolated after a single treatment of the parent culture with N-methyl-N'-nitro-N-nitroso-guanidine. In contrast to LLC-PK1 cells, the mutant did not exhibit production of urokinase-type plasminogen activator (uPA) in response to the hormones calcitonin and vasopressin, but produced the expected levels of uPA upon stimulation by the receptor-independent adenylate cyclase activators forskolin and cholera toxin, as well as by the phosphodiesterase inhibitor isobutylmethylxanthine and the 8-bromo analogue of adenosine cyclic monophosphate, Br8cAMP. The patterns of activation of cAMP-dependent protein kinase were identical to those of uPA induction: calcitonin and vasopressin were without effect, but the response to all other agents was normal. In similar fashion, mutant cell homogenates displayed normal activation of adenylate cyclase upon treatment with sodium fluoride, forskolin, or the non-hydrolyzable GTP analogue guanosine 5'-[beta, gamma-imino]triphosphate, but were unresponsive to calcitonin or vasopressin. The ability of M18 cells to bind radioactively labelled calcitonin and vasopressin was measured. The mutant possessed less than 4% of the normal levels of the receptor binding activity for both hormones. Somatic cell hybrids formed between M18 and LLC-PK1 cells were found to retain normal hormone binding activity and responsiveness to hormones, indicating that the defect in M18 cells was recessive. M18 was concluded most probably to contain a single mutation impairing the function of two distinct polypeptide hormone receptors.

Adenylyl Cyclases↗
PubMed1986

Leftwards error in bisecting the gap between two points: stimulus quality and hand effects.

Subjects attempted to bisect the gap between two LEDs; these differed from each other in brightness, stimulus duration, onset/offset (a) synchronies, and in continuous or flashing mode of presentation. There was a systematic bias to the left, especially with the left hand, indicating a motor contribution to this perceptual task. A brief, faint or flashing LED attracted the subjective midpoint, perhaps because of increased processing demands; indeed the general leftwards bias was attributed to a greater visuospatial processing capacity in the right hemisphere. Leftwards bias was rather greater when central fixation was maintained, indicating that hemispatial mechanisms may be more important than anatomical connectivities. The technique may be useful for understanding and treating unilateral neglect.

Attention↗
PubMed1986

Lateralized recognition of incomplete figures in a prolonged display controlled by eye movements.

A left field superiority is typically reported for processing a variety of simple and complex non-verbal and patterned visual stimuli, including pictures, though stimulus clarity, degradation and exposure duration may be a significant determinant. Clinical studies indicate deficits in the ability to recognize incomplete figures with right hemisphere damage. However when normal subjects attempted to recognize 80 series of progressively-less-incomplete common objects (each series graded in 10 steps) presented for prolonged inspection to one or other visual field via a display driven by an infrared eyemovement transducer, either field (hemisphere) proved to be equally competent. We review evidence to suggest that such "ecologically-more-valid" techniques may not in fact be intrinsically able to tap minor hemisphere function.

Dominance, Cerebral↗
PubMed1983

Effects of GABA receptor agonists on [3H] flunitrazepam binding to rat cerebellar and hippocampal membranes.

The effects of GABA agonists on [3H] flunitrazepam binding were examined in membranes from CNS areas proposed to contain different populations of benzodiazepine binding site subtypes (BZ1/BZ2). Since these effects were broadly similar in both cerebellar and hippocampal membranes, it seems unlikely that GABA receptors interacting with the proposed BZ1/BZ2 binding sites have markedly different properties. Sodium chloride clearly facilitated the potentiating effect of muscimol on [3H] flunitrazepam binding but produced a complex interaction with the effects of GABA itself and the partial agonist imidazoleacetic acid in the phosphate buffer system used.

Animals↗
PubMed1983

Head and body hemispace to left and right III: Vibrotactile stimulation and sensory and motor components.

Response latencies were measured to vibrotactile stimulation delivered to the forefingers of the left or right hands which were positioned ipsilaterally or contralaterally (across the midline) in left or right hemispace. While the two hands did not differ in speed of response, either hand performed better when located in right hemispace (experiment 1). This effect was greatly reduced, though not eliminated, with 90 degrees lateral head turn, when performance was better with stimulation and responding in right-of-head hemispace, but not right-of-body hemispace (experiment 2). When different hands received stimulation and initiated responses, and were located in either the same or opposite hemispace, right-hemispace superiority was found to be motor rather than sensory (experiment 3). These findings are discussed in the context of the true and the phenomenological midline and the clinical syndrome of hemineglect.

Adult↗