Biomedical subjects

Huiling Duan

Publications and source records attributed to Huiling Duan.

4 recordsLinked to original sources

PubMed2005

[Electrocardiograph beat pattern recognition].

It is very important to recognize arrhythmia in clinical electrocardiography (ECG) analysis. The fundamental of beat pattern recognition is presented in this paper. Various prevalent methods for arrhythmia recognitiion are categorized and summarized, based on which the advantages and disadvantages among the methods are compared, and the main problems are discussed in depth. At last, the development trend of arrhythmia recognition technology is pointed out.

Algorithms↗

PubMed2003

Age-related dendritic and spine changes in corticocortically projecting neurons in macaque monkeys.

Alterations in neuronal morphology occur in primate cerebral cortex during normal aging, vary depending on the neuronal type, region and cortical layer, and have been related to memory and cognitive impairment. We analyzed how such changes affect a specific subpopulation of cortical neurons forming long corticocortical projections from the superior temporal cortex to prefrontal area 46. These neurons were identified by retrograde transport in young and old macaque monkeys. Dendritic arbors of retrogradely labeled neurons were visualized in brain slices by intracellular injection of Lucifer Yellow, and reconstructed three-dimensionally using computer-assisted morphometry. Total dendritic length, numbers of segments, numbers of spines, and spine density were analyzed in layer III pyramidal neurons forming the projection considered. Sholl analysis was used to determine potential age-related changes in dendritic complexity. We observed statistically significant age-related decreases in spine numbers and density on both apical and basal dendritic arbors in these projection neurons. On apical dendrites, changes in spine numbers occurred mainly on the proximal dendrites but spine density decreased uniformly among the different branch orders. On basal dendrites, spine numbers and density decreased preferentially on distal branches. Regressive dendritic changes were observed only in one particular portion of the apical dendrites, with the general dendritic morphology and extent otherwise unaffected by aging. In view of the fact that there is no neuronal loss in neocortex and hippocampus in old macaque monkeys, it is possible that the memory and cognitive decline known to occur in these animals is related to rather subtle changes in the morphological and molecular integrity of neurons subserving identifiable neocortical association circuits that play a critical role in cognition.

Aging↗

PubMed2002

Age-related changes in GluR2 and NMDAR1 glutamate receptor subunit protein immunoreactivity in corticocortically projecting neurons in macaque and patas monkeys.

A distinct subpopulation of neurons forming long corticocortical projections in the association neocortex is highly vulnerable to the degenerative process in Alzheimer's disease. However, the degree to which age-related molecular and morphologic alterations of identifiable neuronal populations reflects early cellular degeneration leading to functional deficits has not yet been fully investigated in the aging brain. We performed an immunohistochemical analysis of neurons forming short and long corticocortical projections in young and old monkeys using antibodies to the GluR2 and NMDAR1 glutamate receptor subunit proteins. Projection neurons differed in their expression of these receptor subunits, as GluR2 was less prevalent than NMDAR1 among retrogradely labeled neurons. Long and short corticocortical pathways in old animals demonstrated a considerable decrease in the proportions of projection neurons containing GluR2 and NMDAR1, an observation that was particularly consistent in the case of GluR2. No age-related differences were observed in distribution of neurofilament protein in either type of projection neurons. These data suggest that cortical neurons furnishing long and short corticocortical projections display consistent neurochemical changes during aging and that a differential decrease in cellular expression of glutamate receptor subunit proteins occurs. The fact that in aging these neurons have lower levels of GluR2 than in young individuals, but comparatively higher levels of NMDAR1 than GluR2, may render them prone to calcium-mediated excitotoxicity, which in humans may be related to the selective vulnerability of such neurons during the course of Alzheimer's disease. Also, it is apparent that age-related neuronal changes are quite subtle and involve subcellular components of the cortical circuits rather than major morphologic alterations.

Aging↗

PubMed2002

Morphological alterations in neurons forming corticocortical projections in the neocortex of aged Patas monkeys.

Recent studies indicate that the cognitive processes mediated by the prefrontal cortex, such as working memory, are impaired during normal aging. These disturbances in cortical function may be a consequence of abnormalities in neocortical circuits, even though the numbers of cortical neurons are preserved in normal aging. We performed retrograde tract-tracing of cortical projections connecting the temporal cortex to the prefrontal cortex in combination with dye-filling and three-dimensional neuronal reconstructions in aged patas monkeys. Age-related changes affected the apparent complexity of the apical dendrites of projection neurons and caused a significant loss of dendritic spines at all levels of their dendritic trees. These results indicate that normal aging is accompanied by neuronal changes that are quite subtle, and possibly involves discrete cellular components of certain cortical neurons selectively rather than inducing major alterations such as cell death.

Aging↗