George J Markelonis

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Spinal cord injury (SCI) causes a permanent neurological disability, and no satisfactory treatment is currently available. After SCI, pro-nerve growth factor (proNGF) is known to play a pivotal role in apoptosis of oligodendrocytes, but the cell types producing proNGF and the signaling pathways involved in proNGF production are primarily unknown. Here, we(More)
We examined the effects of minocycline, an anti-inflammatory drug, on functional recovery following spinal cord injury (SCI). Rats received a mild, weight-drop contusion injury to the spinal cord and were treated with the vehicle or minocycline at a dose of 90 mg/kg immediately after SCI and then twice at a dose of 45 mg/kg every 12 h. Injecting minocycline(More)
Certain natural products and Asian herbal remedies have been used in Asia to attenuate neurodegenerative diseases, including senile dementia. We have examined derivatives of several natural products for potential neuroprotective activity in an in vitro test system. In the present study, we assayed a number of compounds that were isolated from Panax ginseng(More)
We evaluated the contribution of p38 mitogen-activated protein kinase and the events upstream/downstream of p38 leading to dopaminergic neuronal death. We utilized MN9D cells and primary cultures of mesencephalic neurons treated with 6-hydroxydopamine. Phosphorylation of p38 preceded apoptosis and was sustained in 6-hydroxydopamine-treated MN9D cells.(More)
We investigated the role of tumor necrosis factor (TNF)-alpha in the onset of neuronal and glial apoptosis after traumatic spinal cord crush injury in rats. A few TUNEL-positive cells were first observed within and surrounding the lesion area 4 h after injury, with the largest number observed 24-48 h after injury. Double-labeling of cells using cell(More)
Recent evidence indicates that estrogen exerts neuroprotective effects in both brain injury and neurodegenerative diseases. We examined the protective effect of estrogen on functional recovery after spinal cord injury (SCI) in rats. 17beta-estradiol (3, 100, or 300 microg/kg) was administered intravenously 1-2 h prior to injury (pre-treatment), and animals(More)
We showed previously that, after spinal cord injury (SCI), tumor necrosis factor-alpha (TNF-alpha) may serve as an external signal, initiating apoptosis in neurons and oligodendrocytes. To further characterize the apoptotic cascade initiated by TNF-alpha after SCI, we examined the expression of TNF-alpha, inducible nitric oxide (NO) synthase (iNOS), and the(More)
Although the cause of neuronal death in Parkinson's disease (PD) is mainly unknown, growing evidence suggests that both apoptotic and non-apoptotic death may occur in PD. Using primary cultures of mesencephalic dopaminergic neurons and the MN9D dopaminergic neuronal cell line, we attempted to evaluate specifically the existence of the mitochondrial(More)
We previously reported that a total methanolic extract of the underground part of Angelica gigas Nakai (Umbelliferae) (here-in-after abbreviated AG) significantly inhibited acetylcholinesterase (AChE) activity. We characterized 12 coumarin derivatives including both decursin and decursinol from extracts of AG. In this study, we evaluated the anti-amnestic(More)
We attempted to ascertain the neuroprotective effects and mechanisms of minocycline in inflammatory-mediated neurotoxicity using primary neuron/glia co-cultures treated with lipopolysaccharide (LPS). Neuronal cell death was induced by treatment with LPS for 48 h, and the cell damage was assessed using lactate dehydrogenase (LDH) assays and by counting(More)