Biomedical subjects

Agnes S Chan

Publications and source records attributed to Agnes S Chan.

22 records · Page 2Linked to original sources

PubMed2003

Recent development of cognitive and neuropsychological assessment in Asian countries.

There is a growing trend of research in neuropsychological assessment in Asia: The mean number of published studies increased from 1.8 in the 1980s to 16.0 in 2 recent years. About 40% of the studies reviewed concerned test development or adaptation, with the latter greatly outnumbering the former. To facilitate the test selection for clinical use, 36 clinical measures were evaluated based on some statistical criteria. The results showed that only 8 neuropsychological tests (5 Chinese, 2 Korean, and 1 Japanese) met the criteria. Given that Asian and Western populations differ on certain cognitive processes, future development of neuropsychological assessment measures in Asia should move from the adaptation of Western tests toward the construction of original tests with better ecological validity.

Adolescent↗

PubMed2003

Conceptual organization in Alzheimer's dementia.

Although episodic memory impairment is usually the earliest feature of Alzheimer's Disease (AD), semantic memory deficits often occur during the course of the disease. The present study is the first to examine the conceptual organization of semantic memory with Chinese AD patients in Hong Kong. In the attempt to minimize the effects of the level of formal education, our procedure involved pictorial sorting tasks similar to the ones used in developmental literature on preschool children. The first condition involved a triadic comparison in which subjects were instructed to find one out of two choice objects which was most related to the target object. This condition was followed by the second condition that involved more specific instructions asking the subjects to find the taxonomic, thematic and shape associate of the target object. Results indicated that AD patients as compared to the controls tended to use more perceptual cues in categorization. The tendency to use perceptual cues for categorization was found to increase with the severity of dementia. These results were discussed in light of the hypothesized structural alteration of semantic networks in AD.

Aged↗

PubMed2002

Identification of a novel gene NCRMS on chromosome 12q21 with differential expression between rhabdomyosarcoma subtypes.

Rhabdomyosarcoma (RMS) is a malignant soft tissue tumor showing varying degrees of skeletal muscle differentiation. Two major histologic subtypes exist, alveolar and embryonal, each with associated molecular genetic changes. We have used Representational Difference Analysis (RDA) to compare gene expression between the two RMS subtypes and have identified the novel gene NCRMS (non-coding RNA in RMS) that has increased expression in the alveolar subtype relative to the embryonal subtype. Multiple alternatively spliced forms of NCRMS were identified through library screening, RACE, and comparison to human expressed sequence tags (ESTs). Northern blot analysis indicated the transcript size to be 1.25 kb in alveolar RMS. There was no sequence homology to any of the known genes in GenBank, but extensive homology to ESTs from various species. Comparison to human genomic sequences identified at least 11 exons mapping to chromosomal region 12q21. Differential expression of NCRMS was noted between various tumor types. Since NCRMS RNA possesses limited potential for protein coding, yet with conserved sequences between different species, it is likely that NCRMS is a functional non-coding RNA. Known genes in its proximity include myogenic regulators Myf5 and Myf6, growth factor Igf1, and another potential differentially expressed gene (ATP2B1) in RMS isolated by RDA.

Alanine Racemase↗

PubMed2002

Cognitive and neuropathologic correlates of Stroop Color-Word Test performance in Alzheimer's disease.

The Stroop Color-Word Test (SCWT; C. Golden, 1978) was examined in 59 patients with probable Alzheimer's disease (AD) and in 51 demographically comparable normal control (NC) participants. AD patients produced significantly larger Stroop interference effects than NC participants, and level of dementia severity significantly influenced SCWT performance. Principal-components analyses demonstrated a dissociation in the factor structure of the Stroop trials between NC participants and AD patients, suggesting that disruption of semantic knowledge and speeded verbal processing in AD may be a major contributor to impairment on the incongruent trial. Results of clinicopathologic correlations in an autopsy-confirmed AD subgroup further suggest the invocation of a broad network of integrated cortical regions and executive and language processes underlying successful SCWT performance.

Aged↗