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Biomedical subjects

R Grieve

Publications and source records attributed to R Grieve.

30 records · Page 2Linked to original sources
PubMed1992

Errors in young children's decisions about traffic gaps: experiments with roadside simulations.

Young children's vulnerability as pedestrians has often been attributed to deficiencies in their decision making about vehicle approach times. Some studies have found a preponderance of risky decisions below the age of eight years. In contrast, studies using a closer simulation of road crossing, known as the pretend road, have found a preponderance of overcautious decisions in young children: traffic gaps of adequate size were frequently rejected (missed opportunities). However, the pretend road has potentially distorting characteristics which may account for this divergent pattern of findings. The experiments reported below show that new simulations that eradicate distortions nevertheless validate the pattern of results produced with the pretend road. Differences between adults and young children were pronounced for missed opportunities, but not for risky decisions. Subsidiary analyses suggest that the risky decisions of the youngest children may have arisen through lapses in attention, rather than deficits in timing. These findings run contrary to the view that attributes young children's pedestrian vulnerability to perceptuo-motor deficiency.

Acceleration↗
PubMed1991

Development and dynamics of regional specialization within the syncytial epidermis of the rat tapeworm, Hymenolepis diminuta.

The epidermis of the tapeworm Hymenolepis diminuta is a highly organized syncytium, composed of an outer layer of continuous cytoplasm, or ectocytoplasm, and an inner layer of nucleated cell bodies, or perikarya. The perikarya are in direct cytoplasmic continuity with the ectocytoplasm via narrow plasmalemma-bound bridges called internuncial process. Although distinct structural and functional differences are apparent between ectocytoplasm and perikarya, all of the perikarya along the body of the cestode are morphologically similar, as are all regions of ectocytoplasm. However, immunocytochemically distinct subpopulations of perikarya and regionally defined areas of ectocytoplasm were identified along the tapeworm strobila by the use of monoclonal antibodies raised against a preparation of isolated tegument. The different types of perikarya and the regionally specialized areas of ectocytoplasm were organized in a topographically precise manner along the body of the parasite. Examination of labeling patterns after colchicine treatment suggests that different types of perikarya are specialized for biosynthesis of specific tegumental molecules and for turnover or recycling of tegumental material. Furthermore, it appears that a 52 kDa polypeptide synthesized by one population of perikarya is transported through the syncytium and ultimately resorbed by a different population of tegumental perikarya. These data suggest that the syncytial epidermis of parasitic platyhelminthes exhibits a more complex organization of function than previously appreciated.

Animals↗
PubMed1982

Mentally retarded children's abilities in the process of comparison.

Mentally retarded children were asked to make various types of comparisons between sets and subsets of objects. Results showed that they succeeded when the comparison involved numerically unequal subsets of objects within the same set. When sets, or subsets, were numerically equal, the children clearly failed; instead of rejecting both alternatives in the comparison question, they selected one. With other comparisons, within and between sets and subsets of objects, the children guessed at an answer, and there was a tendency to answer in accordance with the most recently uttered part of the comparison question. These results indicate that although retarded children are thoroughly acquainted with certain aspects of language and its use in the process of comparison, other important aspects have yet to be learned.

Adolescent↗
PubMed1978

Social and attentional aspects of echolalia in highly echolalic mentally retarded persons.

Echolalia was examined in a sample of highly echolalic mentally retarded individuals. When presented with a standard set of questions, under conditions differing in appropriateness for exchange of discourse (e.g., questions presented with examiner and patient face-to-face vs. questions presented with the examiner's face averted vs. questions addressed towards another person sitting silently beside the patient), subjects' frequency of echolalia varied. Besides showing considerable sensitivity to aspects of discourse exchange, subjects exhibited some limited capacity for processing linguistic information.

Adolescent↗
PubMedDate not supplied

Economic evaluation for hepatitis C.

This paper describes the methods used in economic evaluation and illustrates the challenges of assessing the cost-effectiveness of new interventions in Hepatitis C (HCV), where the impact of interventions needs to be assessed over the patient's lifetime. This paper provides an example of an economic evaluation in HCV using a model estimating the cost-effectiveness of combination therapy (CMB) for patients with mild HCV. The preliminary results from the model suggested that for 1000 cases with mild disease CMB lead to 55 fewer deaths from liver disease compared to no treatment, an average gain of 1.2 life years. Although CMB lead to additional costs of 14,882 EURO's, the cost-effectiveness ratio was 8,490 EURO's per Quality Adjusted Life Year (QALY), which suggests the intervention is relatively cost-effective. The sensitivity analysis showed that the cost-effectiveness ratio was sensitive to the effectiveness of the intervention, and the progression rates between mild disease and cirrhosis. A large UK study is collecting data on the effectiveness of CMB for patients with mild disease, and the costs and quality of life for patients at different stages of HCV. These data will be used to improve the projections of the model. In general, economic evaluations can provide information to help decide where priorities lie both in HCV, and other disease areas.

Cost-Benefit Analysis↗