Seung-Wan Son

Ethanol extract of Astragali Radix and Salviae Miltiorrhizae Radix, Myelophil, exerts anti-amnesic effect in a mouse model of scopolamine-induced memory deficits.

ETHNOPHARMACOLOGICAL RELEVANCE Myelophil, a combination of extracts taken from Astragali Radix and Salviae Miltiorrhizae Radix, is a traditional Chinese medicine used for the treatment of chronic fatigue-associated disorders. Here we examined the ability of Myelophil to alleviate memory impairment in a mouse model. We aimed to investigate whether Myelophil has the pharmacological effects on memory deficits associated with brain dysfunctions using an animal model. MATERIALS AND METHODS Ten week-old male C57BL/6N mice were pretreated with Myelophil (50, 100, or 200 mg/kg), or tacrine (10 mg/kg) for 7 days, and then intraperitoneally injected with scopolamine (1 mg/kg). Memory-related behaviors were evaluated using the Morris water maze for 5 days. Levels of biomarkers of oxidative stress, antioxidant activity, acetylcholinesterase (AChE) activity, and extracellular signal-regulated kinase (ERK) were measured in brain tissues. RESULTS Scopolamine treatment increased the escape latency time and shortened time spent in the target quadrant; these effects were ameliorated by pretreatment with Myelophil. Scopolamine-induced changes in reactive oxygen species (ROS), malondialehyde (MDA), and AChE activity were significantly attenuated in mice pretreated with Myelophil. Recovery of antioxidant capacities, including total glutathione (GSH) content, and the activities of GSH-reductase, GSH-S-transferase, and catalase was also evident in Myelophil-treated mice. The strongest effects were seen for ERK and muscarinic acetylcholine receptor 1 (mAChR1) at both the protein and gene expression levels, with significant amelioration of expression levels in the Myelophil pretreatment group. CONCLUSIONS These results suggest that Myelophil confers anti-amnesic properties in a mouse model of memory impairment, driven in part by the modulation of cholinergic activity.

Aqueous extract of Artemisia iwayomogi Kitamura attenuates cholestatic liver fibrosis in a rat model of bile duct ligation

Cholestatic liver fibrosis, characterized by excessive accumulation of extracellular matrix (ECM) proteins, is associated with bile acid-induced oxidative stress and lipid peroxidation. We evaluated the therapeutic or protective effect of an aqueous extract of Artemisia iwayomogi Kitamura (WAI) in a rat bile duct ligation (BDL)-induced hepatic fibrogenesis model. After BDL, rats were treated once daily with 25 or 50 mg/kg of WAI for 2weeks. The serum bilirubin, aspartate transaminase, alanine transaminase, malondialdehyde, and liver hydroxyproline levels were drastically increased in the BDL group. WAI administration significantly reduced these markers and restored BDL-induced depletion of glutathione content and glutathione peroxidase activity. Cholestatic liver injury and collagen deposition were markedly attenuated by WAI treatment, and these changes were paralleled by significantly suppressed gene and protein expression of fibrogenic factors, including hepatic alphasmooth muscle actin, platelet-derived growth factor, and transforming growth factor β. Our data suggest that WAI may have antifibrotic properties via both improvement of antioxidant activities and inhibition of ECM protein production in the rat model of BDL.

Artemisia capillaris extract protects against bile duct ligation-induced liver fibrosis in rats

Artemisia capillaris has been widely used as a traditional herbal medicine in the treatment of liver diseases. However, no previous study has investigated whether A. capillaries alone is effective in treating pathological conditions associated with cholestatic liver injury. In the present study, we evaluated the anti-hepatofibrotic effects of A. capillaris (aqueous extract, WAC) in a bile duct ligation (BDL)-induced cholestatic fibrosis model. After BDL, rats were given WAC (25 or 50 mg/kg) or urosodeoxycholic acid (UDCA, 25 mg/kg) orally for 2 weeks (once per day). The serum cholestatic markers, malondialdehyde, and liver hydroxyproline levels were drastically increased in the BDL group, while administering WAC significantly reduced these alterations. Administering WAC also restored the BDL-induced depletion of glutathione content and glutathione peroxidase activity. Cholestatic liver injury and collagen deposition were markedly attenuated by WAC treatment, and these changes were paralleled by the significantly suppressed expression of fibrogenic factors, including hepatic alpha-smooth muscle actin (α-SMA), platelet-derived growth factor (PDGF), and transforming growth factor beta (TGF-β). The beneficial effects of WAC administration are associated with antifibrotic properties via both upregulation of antioxidant activities and downregulation of ECM protein production in the rat BDL model.

Myelophil ameliorates brain oxidative stress in mice subjected to restraint stress.

We evaluated the pharmacological effects of Myelophil, a 30% ethanol extract of a mix of Astragali Radix and Salviae Radix, on oxidative stress-induced brain damage in mice caused by restraint stress. C57BL/6 male mice (eight weeks old) underwent daily oral administration of distilled water, Myelophil (25, 50, or 100mg/kg), or ascorbic acid (100mg/kg) 1h before induction of restraint stress, which involved 3h of immobilization per day for 21days. Nitric oxide levels, lipid peroxidation, activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione redox system enzymes), and concentrations of adrenaline, corticosterone, and interferon-γ, were measured in brain tissues and/or sera. Restraint stress-induced increases in nitric oxide levels (serum and brain tissues) and lipid peroxidation (brain tissues) were significantly attenuated by Myelophil treatment. Restraint stress moderately lowered total antioxidant capacity, catalase activity, glutathione content, and the activities of glutathione reductase, glutathione peroxidase, and glutathione S-transferase; all these responses were reversed by Myelophil. Myelophil significantly attenuated the elevated serum concentrations of adrenaline and corticosterone and restored serum and brain interferon-γ levels. Moreover, Myelophil normalized expression of the genes encoding monoamine oxidase A, catechol-O-methyltransferase, and phenylethanolamine N-methyltransferase, which was up-regulated by restraint stress in brain tissues. These results suggest that Myelophil has pharmacological properties protects brain tissues against stress-associated oxidative stress damage, perhaps in part through regulation of stress hormones.

Myelophil attenuates brain oxidative damage by modulating the hypothalamus-pituitary-adrenal (HPA) axis in a chronic cold-stress mouse model

ETHNOPHARMACOLOGICAL RELEVANCE Myelophil is composed of Astragali Radix and Salviae Miltiorrhizae Radix, according to the long traditional pharmacological practices, and it has been used for patients with chronic fatigue-associated symptoms including concentration problem or memory loss. AIM OF THE STUDY This study aimed to evaluate the clinical relevance of Myelophil on brain oxidative damage using a chronic cold stress mice model. MATERIAL AND METHODS Balb/c mice were subjected to cold stress (4°C for 4h) six times per week for 2 weeks with or without oral administration of Myelophil (50, 100, or 200mg/kg), or ascorbic acid (50mg/kg). RESULTS Chronic cold stress induced histopathological hippocampal apoptosis with drastically increased serum levels of total reactive oxygen species and nitric oxide, as well as brain lipid peroxidation levels, protein carbonyl, and caspase-3/7 activity. These alterations were significantly ameliorated by Myelophil treatment. Myelophil administration significantly recovered the depleted glutathione and its enzymes, superoxide dismutase activity, and catalase protein and gene expression levels. Serum levels of corticosterone, dopamine, and adrenaline were notably altered by chronic cold stress but were significantly ameliorated by Myelophil treatment. Myelophil also normalized alterations in tumor necrosis factor-α, interleukin (IL)-1β, and IL-10 gene expression and protein levels. Chronic cold stress up-regulated gene expression levels of phenylethanolamine N-methyltransferase and monoamine oxidase-B, and glucocorticoid receptors in the hypothalamus and hippocampus, respectively, whereas Myelophil treatment completely normalized these levels. CONCLUSIONS These results suggest that Myelophil has potent pharmaceutical effects against chronic cold-stress-induced brain damage by relieving oxidative stress and inflammation and regulating stress hormones in mice.

Testosterone depletion increases the susceptibility of brain tissue to oxidative damage in a restraint stress mouse model.

Among sex hormones, estrogen is particularly well known to act as neuroprotective agent. Unlike estrogen, testosterone has not been well investigated in regard to its effects on the brain, especially under psychological stress. To investigate the role of testosterone in oxidative brain injuries under psychological stress, we adapted an orchiectomy and restraint stress model. BALB/c mice were subjected to either an orchiectomy or sham operation. After allowing 15 days for recovery, mice were re‐divided into four groups according to exposure of restraint stress: sham, sham plus stress, orchiectomy, and orchiectomy plus stress. Serum testosterone was undetectable in orchiectomized groups and restraint‐induced stress significantly reduced testosterone levels in sham plus stress group. The serum levels of corticosterone and adrenaline were notably elevated by restraint stress, and these elevated hormones were markedly augmented by orchiectomy. Two oxidative stressors and biomarkers for lipid and protein peroxidation were significantly increased in the cerebral cortex and hippocampus by restraint stress, while the reverse pattern was observed in antioxidant enzymes. These results were supported by histopathological findings, with 4‐hydroxynonenal staining for oxidative injury and Fluoro‐Jade B staining showing the degenerating neurons. The aforementioned patterns of oxidative injury were accelerated by orchiectomy. These findings strongly suggest the conclusion that testosterone exerts a protective effect against oxidative brain damage, especially under stressed conditions.

Fabrication and characterization of metal-semiconductor field-effect-transistor-type quantum devices

Quantum dot transistors and nanowire transistors are fabricated from a metal-semiconductor field-effect-transistor-type wafer and are characterized at low temperatures. Clear single-electron tunneling and various quantum effects, such as transport through excited states and negative differential resistance, are observed in our wire device. Our data suggest that the potential fluctuation of the heavily doped GaAs layer has a much larger characteristic length than interimpurity spacing, and that this is due to the low ionization rate (approximately 10%) of the dopant atoms at 4.2 K.Quantum dot transistors and nanowire transistors are fabricated from a metal-semiconductor field-effect-transistor-type wafer and are characterized at low temperatures. Clear single-electron tunneling and various quantum effects, such as transport through excited states and negative differential resistance, are observed in our wire device. Our data suggest that the potential fluctuation of the heavily doped GaAs layer has a much larger characteristic length than interimpurity spacing, and that this is due to the low ionization rate (approximately 10%) of the dopant atoms at 4.2 K.

Anti-melanoma activity of Cynanchi atrati Radix is mediated by regulation of NF-kappa B activity and pro-apoptotic proteins.

ETHNOPHARMACOLOGICAL RELEVANCE Cynanchi atrati Radix has been traditionally prescribed for patients with inflammatory fever or chronic tumoral disorders. Melanoma is one of the most devastating cancer types, in which overexpression of nuclear factor kappa B (NF-κB) enables the cancer to survive without apoptosis. To identify a potential anti-melanoma candidate, we evaluated the apoptotic activity of an ethanol extract of Cynanchi atrati Radix (CAE) on melanoma and its underlying mechanisms. MATERIALS AND METHODS Sixty C57BL/6N mice with melanoma were orally administrated CAE (100 or 200mg/kg) or distilled water for 10 days. Survival, tumor weight and volume were monitored and measured. Intratumoral apoptotic change was measured using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. To confirm the pro-apoptotic activity of CAE (10, 50 or 100μg/mL) compared to positive drug (10μg/mL of IKK-2 inhibitor IV), cell proliferation, caspase-3/7 activity, flow cytometric analysis, TUNEL and DAPI staining, immunoblotting and gene expression analyses for apoptosis-associated genes were conducted using B16F10 cell line. RESULTS CAE administration remarkably improved survivability with a significant reduction in tumor weight (p<0.01) and volume (p<0.01), as well as increased apoptotic bodies in melanoma tissue. The CAE treatment significantly inhibited proliferation of B16F10 cells (p<0.001), but increased caspase-3/7 activity (p<0.01 or 0.001) and apoptotic population. The CAE partially blocked nuclear translocation of NF-κB but activated the p53-associated apoptotic pathway. CONCLUSION These results indicate that the CAE has anti-melanoma potential, and the underlying mechanisms involve inhibition of the activities of NF-κB and its target proteins as well as promoting the activities of pro-apoptotic proteins.

Radio frequency electrical pulse characterization of defect states in a GaAs/AlGaAs narrow channel field effect transistor

We report electrical pulse-and-probe characterization of trap states in a GaAs/AlGaAs narrow channel field effect transistor (NCFET) up to the frequency (f) of 3 GHz. From our measured data and quantitative modeling of trap dynamics, we successfully obtain the characteristic frequency of surface traps (∼1.4 and ∼100 kHz) and that of bulk deep levels (∼10 MHz). We find that these frequencies are consistent with the results of earlier studies on larger devices. The measured data also shows the intrinsic cutoff frequency of the device (∼500 MHz), which is consistent with the transconductance and the gate capacitance of the device. Our technique can be applied to other 1D material whose capacitance is small and conventional probing technique is not efficient.

A transmission-type radio-frequency single-electron transistor (RF-SET) with an in-plane-gate SET (IPG-SET)

1 Dept. of Information & Control Eng. and Graduate School of Bio-Environment & Information Technology, Hankyong National University, 67 Seokjeong, Anseong, Kyeonggi-do 456-749, Korea Phone: +82-31-670-5293 E-mail: ysyu@hknu.ac.kr 2 Dept. of Electronics & Computer Engineering, Korea University, 136-701 Korea 3 Institute of Quantum Information Processing and Systems, University of Seoul, 130-743 Korea