ABSTRACT
Platelet-derived growth factor (PDGF) was initially described for its mitogenic activity on smooth muscle cells, fibroblast, and glial cells. The biological activities of PDGF include stimulation of mitogenesis, differentiation, wound healing, inflammation, and tumor formation. The localization of platelet-derived growth factor-alpha Receptor (PDGF-alpha R) in central nervous system was commonly restricted to oligodendrocyte progenitors during late embryonic and postnatal development. However, several studies recently demonstrated that postnatal neurons could also synthesize PDGF-alpha R in rodents. In the present study, to analyze the distributional pattern of PDGF-alpha R during postnatal development of the canine CNS, we used immunohistochemical method on sections of canine brain tissue. We found that neurons of various CNS regions, including cerebral cortex, striatum, diencephalon, nuclei of brain stem, cerebellum, spinal cord, exhibited the immunoreactivity to PDGF-alpha R as early as postnatal day 0. Generally PDGF-alpha R immunoreactivity was well localized in the dendrites and axons of neuron during the postnatal day 14 and postnatal day 28, and then showed diminished pattern. But neuronal immunoreactivity to PDGF-alpha R were maintained postnatal 6 month. These results suggest that the localization of PDGF-alpha R in postnatal developing neurons supports the several roles of PDGF for neurons including maturation and survival.
Subject(s)
Axons , Brain , Brain Stem , Central Nervous System , Cerebellum , Cerebral Cortex , Dendrites , Diencephalon , Fibroblasts , Immunohistochemistry , Inflammation , Myocytes, Smooth Muscle , Neuroglia , Neurons , Oligodendroglia , Platelet-Derived Growth Factor , Rodentia , Spinal Cord , Wound HealingABSTRACT
For the evaluation of exercise induced R wave amplitude changes in lead V5 (big up tri, openR) and multiple leads(summation operatorR), we studied 20 normal subjects and 21 ischemic heart disease patients with positive exercise test. All underwent submaximal, multiple leads multistage treadmill exercise testing. 14 to 20 normal subjects(70%) there were decreased R wave amplitude in multiple leads on treadmill exercise testing. 16 of 21 patients(76%) there were increased R wave amplitude on treadmill exercise testing. In normal group, R wave amplitude between rest and exercise was significantly decreased in lead V5 and multiple leads. In patients grous, R wave amplitude between rest and exercise was significantly increased in lead V5 and multiple leads. It is suggested exercise induced R wave amplitude changes probably enhance the diagnostic reliability by ST segment changes on treadmill exercise testing.