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Te-Chung Lee

Publications and source records attributed to Te-Chung Lee.

3 recordsLinked to original sources
PubMed2005

Adenoviral gene transfer of FGF-5 to hibernating myocardium improves function and stimulates myocytes to hypertrophy and reenter the cell cycle.

Fibroblast growth factors (FGFs) have diverse actions on the myocardium but the importance of stimulating angiogenesis versus direct effects of FGFs on cardiac myocytes is unclear. We used intracoronary injection of a replication-deficient adenoviral construct overexpressing FGF-5 (AdvFGF-5) to improve flow and function in swine with hibernating myocardium. Two-weeks after AdvFGF-5 (n=8), wall-thickening increased from 2.4+/-0.04 to 4.7+/-0.7 mm in hibernating LAD regions (P<0.05) whereas remote wall-thickening was unchanged (6.7+/-0.4 to 5.8+/-0.5 mm). This was associated with small increases in resting flow to dysfunctional myocardium, but flow during adenosine was unchanged (LAD 1.45+/-0.27 versus 1.46+/-0.23 mL/min per g and remote 4.84+/-0.23 versus 4.71+/-0.47 mL/min per g, P=NS). Unexpectedly, animals receiving AdvFGF-5 demonstrated a 29% increase in LV mass over the 2-week period (P<0.05 versus untreated animals with hibernating myocardium and normal shams). Histological analysis confirmed profound myocyte cellular hypertrophy in AdvFGF-5 treated myocardium (19.9+/-0.32 versus 15.2+/-0.92 microm in untreated, P<0.001). Myocytes in the proliferative phase of the cell cycle (Ki-67 staining) increased 7-fold after AdvFGF-5 (2,904+/-405 versus 409+/-233 per 10(6) myocyte nuclei in untreated, P<0.05). Myocyte nuclei in the mitotic phase (phosphorylated histone H3 staining) also increased after AdvFGF-5 (127+/-24 versus 35+/-13 per 10(6) myocyte nuclei in untreated, P<0.05). Thus, rather than angiogenesis, stimulation of hypertrophy and reentry of a small number of myocytes into the mitotic phase of the cell cycle are responsible for the effects of AdvFGF-5 on function. Although additional mechanisms may contribute to the improvement in wall-thickening, overexpression of AdvFGF-5 may afford a way to restore function in hibernating myocardium and ameliorate heart failure in chronic ischemic cardiomyopathy.

Adenoviridae↗
PubMed2004

Changes in NMDA receptor expression in auditory cortex after learning.

Extensive practice on auditory learning tasks dramatically alters the functional organization and response properties of neurons in the auditory cortex. The cellular mechanisms responsible for this auditory learning-induced cortical plasticity are unclear; however, changes in synaptic function involving NMDA receptors have been strongly implicated. To test this hypothesis, we measured the change in gene expression of NMDA receptors and associated proteins in the auditory cortex of adult rats trained to perform an auditory identification task. NMDA receptor 2A and 2B gene expression in auditory cortex decreased significantly as auditory discrimination improved whereas expression of Arc, an immediate early gene involved in memory stabilization, increased. These results suggest that changes in NMDA receptors 2A and 2B and Arc enhance synaptic plasticity, thereby facilitating experience-dependent cortical remodeling and auditory learning.

Adaptation, Physiological↗