-
[show abstract]
[hide abstract]
ABSTRACT: A focal stimulus triggers neural activity that spreads to cortical regions far beyond the stimulation site, creating a so-called "cortical point spread" (CPS). Animal studies found that V1 neurons possess lateral connections with neighboring neurons that prefer similar orientations and to neurons representing visuotopic regions that are constrained by their preferred orientation axis. Although various roles in visual processing are proposed for this anatomical anisotropy of lateral connections, evidence for a corresponding "functional" anisotropy in CPS is lacking or inconsistent in animal studies and absent in humans. To explore functional anisotropy, we inspected axial constraints on CPS in human visual cortex using functional magnetic resonance imaging. We defined receptive fields (RFs) of unit gray matter volumes and delineated the spatial extents of CPS in visuotopic space. The CPS triggered by foveal stimuli exhibited coaxial anisotropy with larger spatial extents along the axis of stimulus orientation. Furthermore, the spatial extents of CPS along the coaxial direction increased with an increasing similarity of local sites to the CPS-inducing stimulus in orientation preference. From CPS driven by multifocal stimuli, the coaxially biased spread was also found in cortical regions in the periphery, albeit reduced in degree, and was invariant to a varying degree of radial relationship between stimuli and RF positions of local sites, rejecting radial bias as an origin of coaxial anisotropy. Our findings provide a bridge between the anatomical anisotropy seen in animal visual cortex and a possible network property supporting spatial contextual effects in human visual perception.
Journal of Neuroscience 01/2013; 33(3):1143-56. · 7.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Purpose: To evaluate the effect of umbilical cord serum (UCS) eye drops on corneal wound healing and haze in a mouse model of ocular chemical burn and compare with that of peripheral blood serum (PBS) eye drops or artificial tears (AT). Methods: Chemical burn of the ocular surface was induced by 1N NaOH in C57BL/6 mice. Injured mice were topically treated with 20% UCS, 20% PBS, or AT four times daily. The changes of corneal epithelial defects and degree of haze were analyzed at 6 h, 1, 2, 3, 5, and 7 days, and histological examination was performed at 3 and 7 days. The concentration of IL-1β in the cornea was measured by enzyme-linked immunosorbent assay at 7 days after treatment. Results: The UCS group showed lower epithelial defect parameters compared with the PBS group at 1 and 2 days (p < 0.05), and with the AT group from 1-5 days (p < 0.05). The haze scores were significantly lower in the UCS group than in the PBS group at 2 and 3 days (p < 0.05), and in the AT group from 2-7 days (p < 0.05). Histological examination showed better epithelial integrity and lower stromal inflammation and edema in the UCS group than the other groups. IL-1β levels were 99.71 ± 85.22 and 230.76 ± 102.67 pg/ml in the UCS and PBS groups, respectively (p = 0.03). Conclusions: UCS eye drops are more effective in improving corneal wound healing and reducing corneal haze compared with PBS eye drops and AT in experimental chemical burns.
Current eye research 10/2012; · 1.51 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We examined renal kallikrein-kinin system (KKS) apoptosis and its related signaling pathway in rat podocytes. In addition, we studied the relationship of cannabinoid receptor 1 (CB(1)R) with high glucose and BK receptors.
Cell viability was determined by an MTT assay and apoptosis by DNA fragmentation assay, while gene expression was investigated by RT-PCR. Protein expression was analyzed by Western blot analysis. A chemical inhibitor or siRNA transfection was used to inhibit B1R, B2R, and CB(1)R signaling.
High glucose (25mM) treatment decreased cell viability and increased DNA fragmentation. High glucose-induced DNA fragmentation and PARP and caspase-3 activations were blocked by both [des-Arg(10)]-HOE 140 (a B1R antagonist) and HOE 140 (a B2R antagonist). High glucose also increased Akt phosphorylation, ER stress-related protein expression, and NF-κB/I-κB phosphorylation in podocytes, which was blocked by both [des-Arg(10)]-HOE 140 and HOE 140. In addition, B1R and B2R siRNA transfections prevented high glucose-induced Akt and NF-κB activations in rat podocytes. Moreover, AM251 (a CB(1)R antagonist) treatment and CB(1)R siRNA transfection blocked the high glucose-induced stimulation of BK receptor expression, Akt activation, and NF-κB activation.
Our study suggests that hyperglycemia induces apoptosis via the stimulation of B1R and B2R expression through CB(1)R activation in rat podocytes in vitro, which is associated with the development of diabetic nephropathy.
Life sciences 07/2012; 91(19-20):895-906. · 2.56 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The short-term toxicity of PAI-N002, a mixture of Schizandra chinensis, Astragalus membranaceus, Artemisia capillaris, and Coriolus versicolor extracts (1 : 1 : 1 : 1), was evaluated in rats. This study also investigated the protective effect of PAI-N002 on liver injury induced
by the co-administration of ethanol and carbon tetrachloride (EC) in rats. PAI-N002 was virtually non-toxic to rats after
a single oral administration, with LD50 values > 5,000 mg/kg. The subacute toxicity study showed that 2-week repeated oral dose of PAI-N002 did not cause any adverse
effects on clinical signs, body weight, food consumption, ophthalmoscopy, hematology, serum biochemistry, gross findings,
and organ weights in rats given up to 1,000 mg/kg/day. When rats with EC-induced hepatotoxicity were treated with PAI-N002
at 250 mg/kg/day for 28 days, PAI-N002 treatment significantly improved EC-induced hepatic injury, as evidenced by the decline
of serum AST and ALT activities and decreased histopathological alterations. PAI-N002 also had an antioxidant benefit by decreasing
the lipid peroxidative product malondialdehyde and increasing the levels of the antioxidant glutathione and the activities
of the antioxidant enzymes catalase, superoxide dismutase, and glutathione-S-transferase. These results indicate that the
short-term treatment of rats with PAI-N002 has no harmful effects and that PAI-N002 has hepatoprotective and antioxidant properties
in EC-induced chronic liver injury in rats.
KeywordsPAI-N002-Ethanol-Carbon tetrachloride-Hepatotoxicity-Protective effect
Molecular and Cellular Toxicology 04/2012; 6(3):239-246. · 0.88 Impact Factor
-
Sok Cheon Pak,
Se-Eun Kim,
Dong-Min Oh,
Kyung Mi Shim,
Moon Jin Jeong,
Sung Chul Lim,
Seung Yeol Nah, Soo Hyun Park,
Seong Soo Kang,
Chang Jong Moon,
Jong Choon Kim,
Sung Ho Kim,
Chun Sik Bae
[show abstract]
[hide abstract]
ABSTRACT: Experimental induction of polycystic ovary (PCO) in rodent resembling some aspects of human PCO syndrome was produced using
the long-acting compound estradiol valerate (EV). Our previous study on the role of Korean red ginseng total saponins in a
steroid-induced PCO rat model demonstrated that electro-acupuncture modulates nerve growth factor (NGF) concentration in the
ovaries. In fact, the involvement of a neurogenic component in the pathology of PCO-related ovarian dysfunction is preceded
by an increase in sympathetic outflow to the ovaries. In the present study, we tested the hypothesis that Korean red ginseng
extract (KRGE) administration modulates sympathetic nerve activity in PCO-induced rats. This was done by analyzing NGF protein
and NGF mRNA expression involved in the pathophysiological process underlying steroid-induced PCO. EV injection resulted in
significantly higher ovarian NGF protein and NGF mRNA expression in PCO-induced rats compared to control rats, and PCO ovaries
were counteracted by KRGE administration with significantly lower expression of NGF protein and NGF mRNA compared to EV treated
ovaries. These results indicate that EV modulates the neurotrophic state of the ovaries, which may be a component of the pathological
process by which EV induces cyst formation and anovulation in rodents.
Archives of Pharmacal Research 04/2012; 32(3):347-352. · 1.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: : To evaluate the expression of CXCL9, -10, and -11 chemokines in the aqueous humor of patients with herpetic endotheliitis.
: Aqueous humor was collected from 26 patients with herpetic endotheliitis and 21 control subjects. The concentrations of CXCL9, -10, and -11 in the aqueous humor were measured with enzyme-linked immunosorbent assays. The correlation between chemokine levels and clinical parameters of disease severity was analyzed. Flow cytometry was performed to count CXCR3 cells and CXCR3CD4 cells in the aqueous humor.
: The concentrations of CXCL9, -10, and -11 were 429.08 ± 297.41 pg/mL, 23,102.49 ± 15,964.95 pg/mL, and 258.25 ± 103.25 pg/mL in patients with herpetic endotheliitis and 16.84 ± 16.73 pg/mL (P < 0.01), 188.45 ± 183.43 pg/mL (P < 0.01), and 7.32 ± 6.45 pg/mL (P < 0.01) in control subjects, respectively. Aqueous chemokine levels correlated significantly with keratitic precipitates and corneal edema in patients with herpetic endotheliitis. The mean percentages of CXCR3 and CXCR3CD4 cells were higher in herpetic endotheliitis patients compared with the controls.
: Expression of CXCL9, -10, and -11 chemokines and their receptor CXCR3 increases in the aqueous humor of patients with herpetic endotheliitis. Chemokine levels are associated with the clinical severity of the disease.
Cornea 02/2012; 31(11):1246-50. · 1.73 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present study investigated the protective effects of pine bark extract (PBE) against hexavalent chromium [Cr(VI)]-induced dermatotoxicity in rats. Skin reactions were evaluated by visual inspection, histopathological changes and oxidative stress parameters. Topical application of Cr(VI) produced a significant increase in the incidence and severity of erythema and edema upon visual inspection. Histopathological examination showed moderate to severe necrosis and desquamation in the epidermis and inflammation and hemorrhage in the dermis. In addition, an increased malondialdehyde (MDA) concentration, and decreased glutathione (GSH), catalase, superoxide dismutase, glutathione-S-transferase (GST) and glutathione reductase of the skin were observed in the Cr(VI) group. On the contrary, concomitant administration with PBE significantly improved Cr(VI)-induced dermatotoxicity, evidenced by a decrease in the incidence and severity of skin irritation and histopathological lesions in a dose-dependent manner. Moreover, PBE treatment reduced MDA concentrations and increased catalase and GST activities in skin tissues, indicating that concomitant administration with PBE effectively prevents Cr(VI)-induced oxidative damage in rats. The results indicate that PBE has a protective effect against Cr(VI)-induced dermatotoxicity and is useful as a protective agent against various dermal lesions induced by oxidative stress. Copyright © 2012 John Wiley & Sons, Ltd.
Phytotherapy Research 02/2012; 26(10):1534-40. · 2.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To evaluate the expression of CCR5 and its ligands CCL3, CCL4, and CCL5 in the tear film and ocular surface and their correlation with disease severity in patients with dry eye disease.
The concentrations of CCL3, CCL4, and CCL5 were measured using enzyme-linked immunosorbent assay in tear samples obtained from forty-three patients with dry eye (17 SS and 26 non-SS patients) and 20 control subjects. The correlation between chemokine levels and tear film and ocular surface parameters was analyzed. Expression of the chemokines and their receptor in the conjunctiva was evaluated using immunohistochemistry. Flow cytometry was performed to detect CCR4+CD4+, CCR5+CD4+, and CCR6+CD4+ cells in the conjunctiva.
The concentrations of CCL3, CCL4, and CCL5 were 25.3 ± 24.2, 4.65 ± 3.21, and 93.12 ± 26.31 pg/mL in control subjects, 92.33 ± 13.23, 263.13 ± 116.13, and 253.64 ± 46.29 pg/mL in patients with non-SS, and 215.56 ± 36.1, 697.85 ± 185.65, and 456.12 ± 92.82 pg/mL in patients with SS. The concentrations showed a significant increase in tears of SS patients compared with those of non-SS patients and control subjects (p < 0.05). CCL5 levels showed significant correlation with tear film break-up time, basal tear secretion, tear clearance rate, keratoepitheliopathy score, and goblet cell density (p < 0.01). Staining for the chemokines and their receptor increased in dry eye patients, especially in those with SS patients. Flow cytometry demonstrated increased numbers of CCR5+CD4+, and CCR6+CD4+ cells in dry eye patients in contrast to CCR4+CD4+ cells.
Expression of CCR5 and its ligands CCL3, CCL4, and CCL5 increase in the tear film and ocular surface of patients with dry eye syndrome, especially in those with SS. CCL5 levels correlate significantly with various tear film and ocular surface parameters.
Current eye research 01/2012; 37(1):12-7. · 1.51 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study investigated the protective effects of melatonin (MLT) against doxorubicin (DXR)-induced testicular toxicity and oxidative stress in rats. DXR was given as a single intraperitoneal dose of 10 mg kg(-1) body weight to male rats at 1 h after MLT treatment on day 6 of the study. MLT at 15 mg kg(-1) body weight was administered daily by gavage for 5 days before DXR treatment followed by an additional dose for 5 days. Sperm analysis, histopathological examination and biochemical methods were used for this investigation. DXR caused a decrease in the weight of seminal vesicles, epididymal sperm count and motility and an increase in the incidence of histopathological changes of the testis. In addition, an increased malondialdehyde (MDA) concentration and decreased glutathione content, glutathione reductase (GR), glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase activities were observed. On the contrary, MLT treatment significantly ameliorated DXR-induced testicular toxicity in rats. Moreover, MDA concentration and GR, GST and SOD activities were not affected when MLT was administered in conjunction with DXR. These results indicate that MLT had a protective effect against DXR-induced testicular toxicity and that the protective effects of MLT may be due to both the inhibition of lipid peroxidation and increased antioxidant activity.
Andrologia 12/2011; 44 Suppl 1:796-803. · 1.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Pancreatic β-cells are major cells responsible for glucose metabolism in the body. Hyperglycemia is known to be a primary factor in the induction of diabetes mellitus. Glutamate is also an excitatory neurotransmitter in diverse organs. Oxidative stress also plays a pivotal role in the development of diabetes mellitus. However, the effect of hyperglycemia in glutamate uptake in the pancreas is not clear. Furthermore, the relationship between high glucose-induced glutamate uptake and oxidative stress has not been investigated. Therefore, this study was conducted to investigate the effect of high glucose on glutamate uptake in pancreatic β-cells. In the present study, 25 mM glucose stimulated the glutamate uptake in HIT-15 cells of hamster pancreatic β-cells. The treatment of 25 mM glucose and 1 mM glutamate also decreased the cell viability in HIT-15 cells. In addition, the treatment of 25 mM glucose induced an increase of lipid peroxide formation. High glucose-induced increase of LPO formation was prevented by the treatment of antioxidants such as N-acetyl-L-cysteine and quercetin. Furthermore, high glucose-induced stimulation of glutamate uptake and decrease of cell viability were also blocked by the treatment of N-acetyl-L-cysteine and quercetin. In conclusion, high glucose stimulated glutamate uptake via oxidative stress in pancreatic β-cells.
Laboratory animal research. 12/2011; 27(4):327-31.
-
[show abstract]
[hide abstract]
ABSTRACT: It has been reported that the levels of erythropoietin are associated with diabetes mellitus. Glomerular epithelial cells, located in the renal cortex, play an important role in the regulation of kidney function and hyperglycemia-induced cell loss of glomerular epithelial cells is implicated in the onset of diabetic nephropathy. This study investigated the effect of high glucose on erythropoietin and erythropoietin receptor expression in rat glomerular epithelial cells. We found that 25 mM D-glucose, but not mannitol or L-glucose, stimulated erythropoietin mRNA and protein expression in a time dependent manner (>4 h) in rat glomerular epithelial cells. In addition, 25 mM glucose, but not mannitol or L-glucose, also increased the phosphorylation of erythropoietin receptor, suggesting a role for erythropoietin receptor phosphorylation in erythropoietin synthesis. We conclude that high glucose stimulates erythropoietin production and erythropoietin receptor phosphorylation in rat glomerular epithelial cells.
Laboratory animal research. 09/2011; 27(3):245-50.
-
[show abstract]
[hide abstract]
ABSTRACT: PuRPOSE: To investigate the severity and duration of desiccating stress-induced dry eye disease between mice with and without a genetic predisposition to spontaneous autoimmunity.
Experimental dry eye was induced in 12- to 16-week-old wild-type C57BL/6 and autoimmune NOD.B10.H2(b) mice by subcutaneous injection of scopolamine with exposure to an air draft for 10 days. Tear volume and corneal smoothness were measured at baseline, 5 and 10 days after desiccating stress, and 3, 7, 14, and 28 days after the removal of desiccating stress. Periodic acid-Schiff staining and immunohistochemistry were performed to evaluate the densities of conjunctival goblet cells and CD4(+) T cells in each group. Interleukin (IL)-1β and IL-6 concentrations in conjunctival tissues were measured by multiplex immunobead assay.
Signs of experimental dry eye were noted at 5 and 10 days after desiccating stress in both strains. After the removal of desiccating stress, in C57BL/6 mice, tear production and corneal smoothness improved at 3 and 7 days, respectively, and conjunctival goblet cells and CD4(+) T-cell densities and cytokine levels returned to baseline levels at 14 days. In contrast, in NOD.B10.H2(b) mice, none of the parameters recovered to baseline levels during a period of 28 days after the removal of desiccating stress.
After the removal of desiccating stress in experimental dry eye, tear volume and ocular surface parameters recovered within 2 weeks in C57BL/6 mice, whereas they remained unchanged in NOD mice. In contrast to autoimmune mice, experimental dry eye can be reversed after the elimination of desiccating stress in nonsusceptible mice.
Investigative ophthalmology & visual science 08/2011; 52(10):7267-73. · 3.43 Impact Factor
-
Seul Ki Lim,
Min Jung Park,
Jae Cheong Lim,
Jong Choon Kim,
Ho Jae Han,
Gye-Yeop Kim,
Benjamin F Cravatt,
Chang Hoon Woo,
Seung Jin Ma,
Kyung Cheol Yoon, Soo Hyun Park
[show abstract]
[hide abstract]
ABSTRACT: Fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of the main endocannabinoid, anandamide, and related fatty acid amides, has emerged as a regulator of endocannabinoid signaling. Retinal pigment epithelial (RPE) cells are believed to be important cells in the pathogenesis of diabetic retinopathy. However, the pathophysiology of FAAH in diabetic retinopathy has not been determined. Thus, we examined the effect of high glucose (HG) on the expression of FAAH and CB(1)R in the ARPE-19 human RPE cells. We found that HG downregulated the expression of FAAH 1 mRNA and protein in ARPE-19 cells. In contrast, it upregulated the expression of CB(1)R mRNA and protein. HG-induced internalization of CB(1)R in HEK 293 cells and ARPE-19 cells was blocked by overexpression of FAAH 1 and treatment with the CB(1)R blocker, AM 251. HG-induced generation of reactive oxygen species and lipid peroxide formation were blocked by the overexpression of FAAH 1. FAAH 1 overexpression also blocked HG-induced expression of CB(1)R in the cytosolic fraction. We also investigated whether the overexpression of FAAH 1 protected against HG-induced apoptosis. High glucose increased the Bax/Bcl-2 ratio and levels of cleaved PARP, cleaved caspase-9 and caspase-3, and reduced cell viability. HG-induced apoptotic effects were reduced by the overexpression of FAAH 1, treatment with the CB(1)R-specific antagonist AM 251 and CB(1)R siRNA transfection. In conclusion, HG-induced apoptosis in ARPE-19 cells by inducing CB(1)R expression through the downregulation of FAAH 1 expression. Our results provide evidence that CB(1)R blockade through the recovery of FAAH 1 expression may be a potential anti-diabetic therapy for the treatment of diabetic retinopathy.
Journal of Cellular Physiology 03/2011; 227(2):569-77. · 3.87 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The endocannabinoid system in animals and humans is involved in the onset of diverse diseases, including obesity and diabetic nephropathy, which is a major end-stage renal disease characterized by high glucose (HG)-induced apoptosis of mesangial cells. Endocannabinoids induce physiological and behavioral effects by activating two specific receptors, cannabinoid receptor 1 (CB(1)R) and cannabinoid receptor 2 (CB(2)R). However, the pathophysiology of CB(1)R in diabetic nephropathy has not been elucidated. We investigated the effects of HG on CB(1)R expression and its signaling pathways in primary cultured rat mesangial cells. HG significantly increased CB(1)R mRNA and protein levels in a time-dependent manner and induced CB(1)R internalization. NF-κB and cPLA(2) were involved in the HG-induced increase in CB(1)R levels. Using a CB(1)R antagonist (AM251) and CB(1) siRNA transfection, we showed that HG-induced CB(1)R is linked to apoptosis. Specifically, HG inhibited the expression of GRP78, but induced increases in endoplasmic reticulum (ER) stress proteins, including phosphorylated (p)-protein kinase-like ER-associated kinase, p-eukaryotic initiation factor 2α, p-activating transcription factor-4, and C/EBP homologous protein. In addition, HG increased the Bax/Bcl-2 ratio and increased the amounts of cleaved poly(ADP-ribose) polymerase and caspase-3. These apoptotic effects were prevented by AM251 and by the downregulation of CB(1)R expression by small interfering RNA. We propose a mechanism by which blockade of CB(1)R attenuates HG-induced apoptosis in rat mesangial cells. Our findings suggest that blockade of CB(1)R may be a potential therapy in diabetic nephropathy.
AJP Renal Physiology 02/2011; 301(1):F179-88. · 4.42 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, the Selective Multiple Acknowledgement (SMA) method, based on Multiple Acknowledgement (MA), is proposed to efficiently reduce the amount of data transmission by redesigning the transmission frame structure and taking into consideration underwater transmission characteristics. The method is suited to integrated underwater system models, as the proposed method can handle the same amount of data in a much more compact frame structure without any appreciable loss of reliability. Herein, the performance of the proposed SMA method was analyzed and compared to those of the conventional Automatic Repeat-reQuest (ARQ), Block Acknowledgement (BA), block response, and MA methods. The efficiency of the underwater sensor network, which forms a large cluster and mostly contains uplink data, is expected to be improved by the proposed method.
Sensors 01/2011; 11(12):11717-35. · 1.74 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Underwater sensor networks are emerging as a promising distributed data management system for various applications in underwater environments, despite their limited accessibility and restricted energy capacity. With the aid of recent developments in ubiquitous data computing, an increasing number of users are expected to overcome low accessibility by applying queries to underwater sensor networks. However, when multiple users send queries to an underwater sensor network in a disorganized manner, it may incur lethal energy waste and problematic network traffic. The current query management mechanisms cannot effectively deal with this matter due to their limited applicability and unrealistic assumptions. In this paper, a novel query management scheme involving query result merging is proposed for underwater sensor networks. The mechanism is based on a relational database model and is adjusted to the practical restrictions affecting underwater communication environments. Network simulations will prove that the scheme becomes more efficient with a greater number of queries and a smaller period range.
Sensors 01/2011; 11(12):11833-55. · 1.74 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Ionizing radiation suppresses neurogenesis in the mammalian brain. This in vitro study compared the detrimental effect of acute gamma-irradiation on immature hippocampal cells with mature cells. Both rat immature (0.5 day in vitro (DIV)) and mature hippocampal cells (14 DIV) were irradiated with 0-4 Gy gamma-rays. Cell viability was analyzed by using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA fragmentation study was performed by extracting intracellular DNA. Morphological features of apoptosis were characterized by 4',6-diamidine-2'-phenylindole, dihydrochloride (DAPI) staining. MTT assay revealed that the survival rate of immature hippocampal cells declined in a dose-dependent manner within the range of irradiation applied, but was not changed in mature cells. Intranucleosomal DNA fragmentation in a ladder like pattern was dose-dependently increased in immature cells, but not in mature cells. The number of apoptotic nuclei in immature cells increased significantly in a dose-dependent manner within the range of irradiation applied. Active caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) expressions in immature hippocampal cells at 6 hr after 2 Gy exposure were markedly higher than control levels. The significantly greater radiosensitivity of immature hippocampal cells than that of the mature cells, indicates that the susceptibility of such hippocampal cells depends on their maturation. In addition, gamma-irradiation may induce caspase-dependent apoptosis in immature hippocampal cells.
Journal of Veterinary Medical Science 05/2010; 72(5):605-9. · 0.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Formaldehyde (FA) is an important substance that induces sick house syndrome and diseases, such as asthma and allergies. Oxidative stress is involved in the development of respiratory disease, and diverse antioxidants may protect respiratory tract cells from apoptosis. Peroxiredoxin is a pivotal endogenous antioxidant. In the present study, FA induced death in A549 cells, a lung epithelial cell line, in a dose-dependent manner. FA also increased lipid peroxide formation (LPO) in A549 cells, suggesting a role for oxidative stress. Additionally, FA decreased peroxiredoxin 2 (Prx 2) protein levels after a 24 or 48h exposure to FA. We also examined whether the FA-induced decrease in Prx 2 was associated with apoptosis. Prx 2 overexpression protected against FA-induced cell apoptosis but not necrosis. Prx 2 overexpression blocked FA-induced increase in Bax, a pro-apoptotic molecule, and a decrease in Bcl-2, an anti-apoptotic molecule. Prx 2 overexpression also protected against FA-induced activation of some special apoptosis-associated proteins [caspase-3, caspase-9, and polypeptide poly (ADP-ribose) polymerase (PARP)]. Furthermore, we examined the signaling molecules involved in the FA-induced decrease in Prx 2 expression. The FA-induced decrease in Prx 2 and increase in cell apoptosis was restored by treatment with SB203580 [a p38 mitogen activated protein kinase (MAPK) inhibitor], but not by SP600125 [a c-jun-N-terminal kinase (JNK) inhibitor]. Also, FA-induced events were blocked by treatment with p38 siRNA, but not by scrambled siRNA. Indeed, FA increased p38 MAPK activation, suggesting a role for p38 MAPK in FA action. In conclusion, FA mediated apoptosis in lung epithelial cells by decreasing Prx 2 via p38 MAPK.
Toxicology 03/2010; 271(3):100-6. · 3.68 Impact Factor
-
Min Jung Park,
Chun Sik Bae,
Seul Ki Lim,
Dong Il Kim,
Jae Cheong Lim,
Jong Choon Kim,
Ho Jae Han,
Jae Hak Moon,
Kye Yeop Kim,
Kyung-Chul Yoon, Soo Hyun Park
[show abstract]
[hide abstract]
ABSTRACT: A lot of anti-diabetic agents using natural plants have been extensively studied. Ginsenosides are known to be used as a remedy for diabetes in Asian countries and American Societies. Diabetic nephropathy is a major complication of diabetes mellitus. Extracellular matrix in mesangial cells is mainly composed of fibronectin and the increase of fibronectin is a hallmark of diabetic nephropathy. Protopenaxadiol (PPD) is a major component of total ginseng. Thus, we examined the regulatory mechanism of PPD derivatives-induced preventive effect of fibronectin expression in mesangial cells cultivated under diabetic condition. In present study, ginsenoside Rb1 prevented the high glucose-induced increase of fibronectin expression in mesangial cells. Ginsenoside Rb2 and Rg3 also mildly inhibited it. However, ginsenoside Rc and Rd did not prevent the high glucose-induced increase of fibronectin expression in mesangial cells. In addition, ginsenoside Rb1 prevented high glucose-induced phosphorylation of p44/42 mitogen activated protein kinase (MAPK), p38 MAPK, JNK/SAPK, and Akt. These results suggest that ginsenoside Rb1 is the most powerful component of PPD derivatives. In conclusion, ginsenoside Rb1 prevented high glucose-induced increase of fibronectin expression via the inhibition of MAPK-Akt signaling cascade.
Archives of Pharmacal Research 01/2010; 33(1):151-7. · 1.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, several MAC scheduling methods applicable to an underwater environment are proposed. Besides, a new marine communication system model was proposed to improve the reliability of the proposed SBMAC method. The scheme minimizes transmission of control frames except for data transmission and various transmission methods and ACK methods can be used together. Simulation models are set indices and analysis of the underwater environment is established to conduct reliable simulations. Consequently, the performance improvement of the proposed method is verified with respect to delay time, data transmission rate, memory utilization, energy efficiency, etc.
Sensors 01/2010; 10(1):501-25. · 1.74 Impact Factor
