Search tips
Search criteria

Results 1-25 (147)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
more »
1.  Increased Expression of Cathelicidin by Direct Activation of Protease-Activated Receptor 2: Possible Implications on the Pathogenesis of Rosacea 
Yonsei Medical Journal  2014;55(6):1648-1655.
Recent findings of increased cathelicidin protein and its proteolytic fragments in rosacea suggest a pathogenic role for cathelicidin in this disease. The relationship between cathelicidin and protease-activated receptor 2 (PAR-2) is therefore of interest, as PAR-2, expressed principally in keratinocytes, regulates pro-inflammatory cytokine expression in the skin. The purpose of this study was to determine the relationship between expression of PAR-2 and cathelicidin in rosacea and to test the effect of direct PAR-2 activation on cathelicidin expression in keratinocytes.
Materials and Methods
Samples from 40 patients with clinicopathologic diagnosis of rosacea and facial skin tissue samples from 20 patients with no specific findings or milium without inflammation were retrieved. Intensities of immunohistochemical staining for PAR-2 and cathelicidin were compared between normal and rosacea-affected skin tissues. Additionally, correlations between PAR-2 and cathelicidin staining intensities within rosacea patients were analyzed. In cultured keratinocytes, changes in PAR-2, cathelicidin, and vascular endothelial growth factor (VEGF) mRNA and protein were analyzed after treatment with PAR-2 activating peptide (AP).
Cathelicidin expression was significantly higher in rosacea skin tissues than in normal tissues (p<0.001), while PAR-2 expression was not significantly higher in rosacea tissues than in normal skin tissues. A positive correlation between PAR-2 and cathelicidin within rosacea samples was observed (R=0.330, p=0.037). After treatment of PAR-2 AP, both mRNA and protein levels for PAR-2, cathelicidin, and VEGF significantly increased in cultured keratinocytes, compared with PAR-2 control peptide treatment.
PAR-2 may participate in the pathogenesis of rosacea through activation of cathelicidin LL-37, a mediator of innate immune responses in the skin.
PMCID: PMC4205707  PMID: 25323904
Cathelicidin; LL-37; PAR-2; rosacea; VEGF
2.  Nanomolar concentration of alpha-synuclein enhances dopaminergic neuronal survival via Akt pathway 
Neural Regeneration Research  2013;8(35):3269-3274.
Although alpha-synuclein is generally thought to have a pathological role in Parkinson's disease, accumulative evidence exists that alpha-synuclein has a neuroprotective effect. The aim of this study was to evaluate the effect of extracellular alpha-synuclein on dopaminergic cell survival. We assessed cell viability using the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltertazolium bromide (MTT) assay both in undifferentiated SH-SY5Y (SHSY) cells and neuronally-differentiated SH-SY5Y (ndSHSY) cells after 24 hour treatment with monomeric alpha-synuclein at various concentrations (0 [control], 50, 100 nmol/L, 1 μmol/L). To determine whether cell viability assessed by MTT assay was affected by cell proliferation, 5-bromo-2’-deoxyuridine (BrdU) incorporation assay was performed. Level of both Akt and phosphorylated Akt was measured using western blot method in ndSHSY cells with or without 24 hour alpha-synuclein treatment. Cell viability was increased in ndSHSY cells at the nanomolar concentration of alpha-synuclein, but not in SHSY cells. Proportion of BrdU-positive ndSHSY cells was decreased in alpha-synuclein-treated group compared with control group. Level of phosphorylated Akt in alpha-synuclein-treated group was higher compared with the control group. Our study shows that extracellular alpha-synuclein at nanomolar concentration benefits dopaminergic cell survival via Akt pathway.
PMCID: PMC4145947  PMID: 25206648
neural regeneration; alpha-synuclein; neuronal survival; nanomolar; extracellular; phosphorylated Akt; SH-SY5Y cell; neuronal differentiation; proliferation; dopaminergic; 5-bromo-2’-deoxyuridine; grants-supported paper; neuroregeneration
4.  Accuracy of the epidural catheter position during the lumbar approach in infants and children: a comparison among L2-3, L3-4, and L4-5 approaches 
Korean Journal of Anesthesiology  2010;58(5):458-463.
The aim of this study was to compare the accuracy of the position of the epidural catheter inserted from three different lumbar intervertebral spaces, L2-3, L3-4, and L4-5, in infants and children.
Seventy-five children were randomly allocated to 3 groups according to the epidural catheter insertion site (L2-3, L3-4, and L4-5). The epidural catheter tip was identified using 50% diluted Iohexol and fluoroscopy. The incidence of correct position was compared among the groups and between infants and children.
The incidence of correct position was significantly higher in the L2-3 group as compared to the L3-4 and L4-5 groups (P = 0.023 and P = 0.046 respectively). The incidence of correct position was higher in infants compared to children (P = 0.017).
The L2-3 intervertebral space is preferable during epidural catheter insertion in children older than 1 year, but a low lumbar level should be considered in infants because they have a higher risk of neural damage.
PMCID: PMC2881521  PMID: 20532054
Epidural analgesia; Pediatrics; Urologic surgery
5.  Interrupted aortic arch diagnosed with loss of femoral pulse in a patient undergoing patent ductus arteriosus ligation -A case report- 
Korean Journal of Anesthesiology  2010;58(5):477-479.
A 12-year-old boy with ventricular septal defect and patent ductus arteriosus was presented to the operating room. Upon clamping the patent ductus arteriosus, the femoral arterial pressure curve was lost; however, it returned upon unclamping. Upon further dissection, an interrupted aortic arch was found between the left subclavian artery and patent ductus arteriosus. The surgery was discontinued for further evaluation.
PMCID: PMC2881524  PMID: 20532057
Blood pressure; Femoral artery; Patent ductus arteriosus
6.  Involvement of lymphocytes in dextran sulfate sodium-induced experimental colitis 
AIM: To investigate the roles of lymphocytes in the development of dextran sulfate sodium-induced colitis.
METHODS: Using various doses of dextran sulfate sodium (DSS), we induced colitis in wild-type B6 control and Rag-1 knockout (H-2b haplotype) mice, and evaluated the colitis in terms of symptomatic and histologic parameters, such as weight loss, survival, severity of diarrhea, shortage of colon length and histological changes. Symptomatic parameters were checked daily and histological changes were scored.
RESULTS: Although development of colitis in Rag-1 knockout mice treated with high dose (5%) of DSS was comparable to that in B6 control mice, colitis progression was much more tolerable in Rag-1 knockout mice compared to than in B6 mice treated with low dose (1.5%) DSS. Symptomatic parameters as well as histopathologic changes were improved in Rag-1 knockout mice.
CONCLUSION: These results indicate that the presence of lymphocytes contributes to colitis progression at low dose of DSS stimulation. Lymphocytes may play roles as an aggravating factor in DSS-induced colitis.
PMCID: PMC4066043  PMID: 16482634
Dextran sulfate sodium; Colitis; Lymphocyte; Rag-1; Knockout
7.  Perioperative and postoperative morbidity after sacrocolpopexy according to age in Korean women 
This study aimed to compare perioperative and postoperative morbidity of older and younger women undergoing sacrocolpopexy (SCP).
A retrospective study included 271 patients who underwent laparotomic SCP for symptomatic pelvic organ prolapse from November 2008 to June 2013 at our institution. By the review of medical records, perioperative and postoperative data including the length of the surgery, estimated blood loss, blood transfusion, the length of hospital stay, wound complications and febrile morbidity were collected. In addition, cardiovascular, pulmonary, gastrointestinal, genitourinary, or neurological adverse events were retrieved. The need for an indwelling urinary catheter or performance of clean intermittent self-catheterization, mesh erosion rate and the number of days required for each were included in the postoperative outcomes. For the outcome variable analyzed in this study, the patients was dichomotized into women aged 65 and older and those younger than 65.
One hundred and thirty-five (49.8%) patients were younger than 65 and 136 (50.2%) were aged 65 and older. Older women had higher body mass index, vaginal parity and prior surgery for hysterectomy than younger women (P<0.05). And older women had higher baseline comorbidities, such as hypertension, diabetes, cardiac disease (P<0.05), and their American society of Anesthesiologist class was higher (P<0.001). In the perioperative and postoperative complication, older group showed no differences in most of the operation-related complication rates, but gastrointestinal complication rate. Also, mesh erosion rate was not found to be significantly different between the two groups at the last visit.
Older women undergoing laparotomic SCP have similar perioperative and postoperative morbidities as younger women, suggesting surgeons can counsel older and younger women similarly in terms of operative risks.
PMCID: PMC4303754  PMID: 25629020
Age; Morbidity; Sacrocolpopexy
8.  A study of structural foot deformity in stroke patients 
[Purpose] The aim of this study was to evaluate the structural deformity of the foot joint on the affected side in hemiplegic patients to examine factors that affect this kind of structural deformity. [Subjects and Methods] Thirty-one hemiplegic patients and 32 normal adults participated. The foot posture index (FPI) was used to examine the shape of the foot, the modified Ashworth scale test was used to examine the degree of ankle joint rigidity, the navicular drop test was used to investigate the degree of navicular change, and the resting calcaneal stance position test was used to identify location change of the heel bone. [Results] The FPIs of the paretic side of the hemiplegic patients, the non-paretic side of the hemiplegic patients, and normal participants were −0.25 ± 2.1, 1.74 ± 2.3, and 2.12 ± 3.4 respectively. [Conclusion] Our findings indicated that in stroke-related hemiplegic patients, the more severe the spasticity, the more supinated the foot. Further, the smaller the degree of change in the navicular height of hemiplegic patients is, the more supinated the paretic side foot is. Additionally, a greater change in the location of the calcaneus was associated with greater supination of the overall foot.
PMCID: PMC4305560  PMID: 25642071
Foot posture index; Hemiplegic foot; Foot deformity
9.  Adrenergic signaling controls RGK-dependent trafficking of cardiac voltage-gated L-type Ca2+ channels through PKD1 
Circulation research  2011;110(1):59-70.
The Rad-Gem/Kir-related family (RGKs) consists of small GTP-binding proteins that strongly inhibit the activity of voltage-gated calcium channels. Among RGKs, Rem1 is strongly and specifically expressed in cardiac tissue. However, the physiological role and regulation of RGKs, and Rem1 in particular, are largely unknown.
To determine if Rem1 function is physiologically regulated by adrenergic signaling, and thus, impacts voltage-gated L-type calcium channel (VLCC) activity in the heart.
Methods and Results
We found that activation of protein kinase D1 (PKD1), a protein kinase downstream of α1-adrenergic signaling, leads to direct phosphorylation of Rem1, at Ser18. This results in an increase of the channel activity and plasma membrane expression, observed by using a combination of electrophysiology, live cell confocal microscopy and immunohistochemistry in heterologous expression system and neonatal cardiomyocytes. In addition, we show that stimulation of α1-adrenergic receptor-PKD1-Rem1 signaling increases transverse-tubule (T-tubule) VLCC expression that results in increases L-type Ca2+ current density in adult ventricular myocytes.
α1-adrenergic stimulation releases Rem1 inhibition of VLCCs through direct phosphorylation of Rem1 at Ser18 by PKD1, resulting in an increase of the channel activity and T-tubule expression. Our results uncover a novel molecular regulatory mechanism of VLCC trafficking and function in the heart, and provide the first demonstration of physiological regulation of RGK function.
PMCID: PMC4232192  PMID: 22076634
Cav1.2; phenylephrine; adrenoceptor; patch clamp
10.  The cytological and molecular role of DOMAINS REARRANGED METHYLTRANSFERASE3 in RNA-dependent DNA methylation of Arabidopsis thaliana 
BMC Research Notes  2014;7(1):721.
Plants have evolved a unique epigenetic process to target DNA cytosine methylation: RNA-directed DNA methylation (RdDM). During RdDM, small RNAs (smRNAs) guide methylation of homologous DNA loci. In Arabidopsis thaliana, the de novo DNA methyltransferase that ultimately methylates cytosines guided by smRNAs in all sequence contexts is DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2). Recent reports have shown that DRM2 requires the catalytic mutated paralog DRM3 to exert its function through a still largely unknown process. To shed light on how DRM3 affects RdDM, we have further characterized its role at the molecular and cytological levels.
Although DRM3 is not required for RdDM loci transcriptional silencing, it specifically affects loci’s DNA methylation. Interestingly, DRM3 and DRM2 regulate the DNA methylation in a subset of loci differently.
Fluorescence In Situ Hybridization and immunolocalization analyses showed that DRM3 is not required for the large-scale nuclear organization of heterochromatin during interphase, with the notable exception of the 45S ribosomal RNA loci. DRM3 localizes exclusively to the nucleus and is enriched in a round-shaped domain located in the nucleolar periphery, in which it colocalizes with components of the RdDM pathway.
Our analyses reinforce the previously proposed chaperone role of DRM3 in RdDM. Overall, our work further demonstrates that DRM3 most likely functions exclusively with DRM2 in RdDM and not with other A. thaliana DNA methyltransferases. However, DRM3’s regulation of DNA methylation is likely target- or chromatin context-dependent. DRM3 hypothetically acts in RdDM either upstream of DRM2, or in a parallel step.
Electronic supplementary material
The online version of this article (doi:10.1186/1756-0500-7-721) contains supplementary material, which is available to authorized users.
PMCID: PMC4209038  PMID: 25316414
Small RNAs; DNA methylation; DRM3; Nuclear localization; Interphase organization
11.  Could clinical experience during clerkship enhance students’ clinical performance? 
BMC Medical Education  2014;14(1):209.
Medical students learn and practice various clinical skills during clinical clerkship. Patient encounters are important for developing clinical thinking, communication skills, and professional attitude. We investigated whether the amount of clinical experience during clerkship correlated with students’ clinical competency and students’ perception of effectiveness of their clerkship on it.
Fourth year medical students undertook the Objective Structured Clinical Examinations (OSCE) in August 2012. Students provided the number of patients for whom they took medical histories or performed physical examinations during clerkship and provided feedback as to whether or not the clinical clerkship was helpful in preparing OSCE. The correlation between the OSCE score and number of patients was analyzed.
One hundred thirty students completed the questionnaire (86.6%). OSCE scores correlated with the total number of patients encountered for physical examinations (correlation coefficient, 0.274; p = 0.0105). Cumulative 3-year GPAs were positively correlated with OSCE scores (correlation coefficient, 0.330; p = 0.0001). Most (92.3%) answered that their clinical clerkship was helpful in preparing them for the OSCE; however, only 20% felt that their clinical clerkship was most helpful. Others felt that role playing (38.46%) or the guide book (33.84%) was most helpful.
The amount of clinical experience during the students’ clerkship had a small but positive relationship with students’ clinical performance. Further research to elucidate the influence of clinical experience on clinical competency is needed.
Electronic supplementary material
The online version of this article (doi:10.1186/1472-6920-14-209) contains supplementary material, which is available to authorized users.
PMCID: PMC4190391  PMID: 25273978
Objective structured clinical examination; Clinical clerkship; Medical education; Clinical competency
12.  The Sequestosome 1/p62 Attenuates Cytokine Gene Expression in Activated Macrophages by Inhibiting IFN Regulatory Factor 8 and TNF Receptor-Associated Factor 6/NF-κB Activity1 
Sequestosome 1/p62 (p62) is a scaffold/adaptor protein with multiple functions implicated for neuronal and bone diseases. It carries a ubiquitin binding domain through which it mediates proteasome-dependent proteolysis. In addition, p62 is reported to regulate NF-κB activity in some cells. To date, however, the role of p62 in innate immunity has not been fully elucidated. In this study, we report that IFN-γ plus TLR signaling stimulates late expression of p62 in murine macrophages. Overexpression of p62 inhibited expression of multiple cytokines, IL-12p40, TNF-α, IL-1β, IL-6, and IFN-β, whereas p62 underexpression by small hairpin RNA markedly elevated their expression, indicating that p62 is a broad negative regulator of cytokine expression in stimulated macrophages. We show that p62 interacts with IFN regulatory factor 8 and Ro52, the transcription factor and ubiquitin E3 ligase that are important for IL-12p40 expression. This interaction, detectable at a late stage in stimulated macrophages, led to increased polyubiquitination and destabilization of IFN regulatory factor 8. We also show that upon macrophage stimulation, p62 binds to TNFR-associated factor 6, another E3 ligase important for NF-κB activation, but later this interaction was replaced by the recruitment of the deubiquitinating enzyme, cylindromatosis, an inhibitor of NF-κB activity. Recruitment of cylindromatosis coincided with reduced TNFR-associated factor 6 autoubiquitination and lower NF-κB activation. Our results indicate that p62 orchestrates orderly regulation of ubiquitin modification processes in macrophages to ensure attenuation of cytokine transcription postactivation. Together, p62 may provide a mechanism by which to control excessive inflammatory responses after macrophage activation.
PMCID: PMC4151355  PMID: 19201866
13.  Evaluation of the genotoxicity of ginseng leaf extract UG0712 
Laboratory Animal Research  2014;30(3):104-111.
Although ginseng (genus Panax) leaf extract contains high concentrations of bioactive constituents, its effects have been reported in few preclinical studies, and information regarding its toxicity is not sufficient to allow for its clinical use. We evaluated the genotoxicity of UG0712, which is a powdered extract of ginseng leaves. UG0712 did not increase the number of revertant colonies in 4 histidine auxotrophic strains of Salmonella typhimurium (TA100, TA1535, TA98, and TA1537) or in a tryptophan auxotrophic strain of Escherichia coli (WP2uvrA(pKM101)) at any concentration evaluated, either in the absence or presence of the metabolic activation system. There was no significant increase in the number of metaphase cells with structural or numerical aberrations in the UG0712-treated groups compared to the concurrent vehicle control at any dose, regardless of the presence of the metabolic activation system. Oral administration of the extract at doses up to 2,000 mg/kg in male mice did not increase the frequency of micronucleated polychromatic erythrocytes in the bone marrow, and did not result in any significant clinical signs, body weight loss, gross findings, or mortality. These results suggest that UG0712 does not act as a mutagenic or genotoxic material at the concentrations evaluated.
PMCID: PMC4188829  PMID: 25324871
UG0712; ginseng leaf extract; bacterial reverse mutation; chromosome aberration; micronucleus
14.  Tracking Intravenous Adipose-Derived Mesenchymal Stem Cells in a Model of Elastase-Induced Emphysema 
Mesenchymal stem cells (MSCs) obtained from bone marrow or adipose tissue can successfully repair emphysematous animal lungs, which is a characteristic of chronic obstructive pulmonary disease. Here, we describe the cellular distribution of MSCs that were intravenously injected into mice with elastase-induced emphysema. The distributions were also compared to the distributions in control mice without emphysema.
We used fluorescence optical imaging with quantum dots (QDs) to track intravenously injected MSCs. In addition, we used a human Alu sequence-based real-time polymerase chain reaction method to assess the lungs, liver, kidney, and spleen in mice with elastase-induced emphysema and control mice at 1, 4, 24, 72, and 168 hours after MSCs injection.
The injected MSCs were detected with QD fluorescence at 1- and 4-hour postinjection, and the human Alu sequence was detected at 1-, 4- and 24-hour postinjection in control mice (lungs only). Injected MSCs remained more in mice with elastase-induced emphysema at 1, 4, and 24 hours after MSCs injection than the control lungs without emphysema.
In conclusion, our results show that injected MSCs were observed at 1 and 4 hours post injection and more MSCs remain in lungs with emphysema.
PMCID: PMC4192309  PMID: 25309606
Mesenchymal Stromal Cells; Emphysema; Cell Tracking; Injections, Intravenous
15.  The Role and Regulatory Mechanism of 14-3-3 Sigma in Human Breast Cancer 
Journal of Breast Cancer  2014;17(3):207-218.
14-3-3 sigma (σ) is considered to be an important tumor suppressor and decreased expression of the same has been reported in many malignant tumors by hypermethylation at its promoter or ubiquitin-mediated proteolysis by estrogen-responsive ring finger protein (Efp). In this study, we investigated the significance of 14-3-3 σ expression in human breast cancer and its regulatory mechanism.
Efp was silenced using small interfering RNA (siRNA) in the MCF-7 breast cancer cell line in order to examine its influence on the level of 14-3-3 σ protein. The methylation status of the 14-3-3 σ promoter was also evaluated by methylation-specific polymerase chain reaction (PCR). The expression of Efp and 14-3-3 σ in 220 human breast carcinoma tissues was assessed by immunohistochemistry. Other clinicopathological parameters were also evaluated.
Silencing Efp in the MCF-7 breast cancer cell line resulted in increased expression of 14-3-3 σ. The Efp-positive human breast cancers were more frequently 14-3-3 σ-negative (60.5% vs. 39.5%). Hypermethylation of 14-3-3 σ was common (64.9%) and had an inverse association with 14-3-3 σ positivity (p=0.072). Positive 14-3-3 σ expression was significantly correlated with poor prognosis: disease-free survival (p=0.008) and disease-specific survival (p=0.009).
Our data suggests that in human breast cancer, the regulation of 14-3-3 σ may involve two mechanisms: ubiquitin-mediated proteolysis by Efp and downregulation by hypermethylation. However, the inactivation of 14-3-3 σ is probably achieved mainly by hypermethylation. Interestingly, 14-3-3 σ turned out to be a very significant poor prognostic indicator, which is in contrast to its previously known function as a tumor suppressor, suggesting a different role of 14-3-3 σ in breast cancer.
PMCID: PMC4197350  PMID: 25320618
Breast neoplasms; Estrogen-responsive finger protein; Methylation; SFN protein
16.  Various Upper Endoscopic Findings of Acute Esophageal Thermal Injury Induced by Diverse Food: A Case Series 
Clinical Endoscopy  2014;47(5):447-451.
Esophageal thermal injury caused by food has been reported to occur mostly after drinking hot liquid food, and is known to produce alternating white and red linear mucosal bands. In addition, thermal injury caused by ingestion of hot solid foods is documented to be a cause of esophageal ulcers or pseudomembranes. From January 2006 to August 2012, five patients with suspected esophageal thermal injury underwent esophagogastroduodenoscopy with biopsy. A "candy-cane" appearance was observed in one case, pseudomembrane was observed in two cases, an esophageal ulcer was observed in one case, and a friable and edematous mucosa was noted in one case. We believe that the endoscopic findings of esophageal thermal injury depend on the following factors: causative materials, amount of food consumed, exposure period, and time to endoscopy after the incident. Therefore, physicians who encounter patients with suspected esophageal thermal injury should carefully take the patient's history considering these factors.
PMCID: PMC4198563  PMID: 25325006
Esophageal thermal injury; Endoscopy, digestive system; Candy-cane appearance
17.  Fabrication of high-quality single-crystal Cu thin films using radio-frequency sputtering 
Scientific Reports  2014;4:6230.
Copper (Cu) thin films have been widely used as electrodes and interconnection wires in integrated electronic circuits, and more recently as substrates for the synthesis of graphene. However, the ultra-high vacuum processes required for high-quality Cu film fabrication, such as molecular beam epitaxy (MBE), restricts mass production with low cost. In this work, we demonstrated high-quality Cu thin films using a single-crystal Cu target and radio-frequency (RF) sputtering technique; the resulting film quality was comparable to that produced using MBE, even under unfavorable conditions for pure Cu film growth. The Cu thin film was epitaxially grown on an Al2O3 (sapphire) (0001) substrate, and had high crystalline orientation along the (111) direction. Despite the 10−3 Pa vacuum conditions, the resulting thin film was oxygen free due to the high chemical stability of the sputtered specimen from a single-crystal target; moreover, the deposited film had >5× higher adhesion force than that produced using a polycrystalline target. This fabrication method enabled Cu films to be obtained using a simple, manufacturing-friendly process on a large-area substrate, making our findings relevant for industrial applications.
PMCID: PMC4148649  PMID: 25169804
18.  Enhancement of the killing effect of low-temperature plasma on Streptococcus mutans by combined treatment with gold nanoparticles 
Recently, non-thermal atmospheric pressure plasma sources have been used for biomedical applications such as sterilization, cancer treatment, blood coagulation, and wound healing. Gold nanoparticles (gNPs) have unique optical properties and are useful for biomedical applications. Although low-temperature plasma has been shown to be effective in killing oral bacteria on agar plates, its bactericidal effect is negligible on the tooth surface. Therefore, we used 30-nm gNPs to enhance the killing effect of low-temperature plasma on human teeth.
We tested the sterilizing effect of low-temperature plasma on Streptococcus mutans (S. mutans) strains. The survival rate was assessed by bacterial viability stains and colony-forming unit counts. Low-temperature plasma treatment alone was effective in killing S. mutans on slide glasses, as shown by the 5-log decrease in viability. However, plasma treatment of bacteria spotted onto tooth surface exhibited a 3-log reduction in viability. After gNPs were added to S. mutans, plasma treatment caused a 5-log reduction in viability, while gNPs alone did not show any bactericidal effect. The morphological changes in S. mutans caused by plasma treatment were examined by transmission electron microscopy, which showed that plasma treatment only perforated the cell walls, while the combination treatment with plasma and gold nanoparticles caused significant cell rupture, causing loss of intracellular components from many cells.
This study demonstrates that low-temperature plasma treatment is effective in killing S. mutans and that its killing effect is further enhanced when used in combination with gNPs.
PMCID: PMC4237858  PMID: 25104171
Gold nanoparticle; Low-temperature plasma; Streptococcus mutans; Sterilization; Oral care
19.  Cancer Cell Growth Inhibitory Effect of Bee Venom via Increase of Death Receptor 3 Expression and Inactivation of NF-kappa B in NSCLC Cells 
Toxins  2014;6(8):2210-2228.
Our previous findings have demonstrated that bee venom (BV) has anti-cancer activity in several cancer cells. However, the effects of BV on lung cancer cell growth have not been reported. Cell viability was determined with trypan blue uptake, soft agar formation as well as DAPI and TUNEL assay. Cell death related protein expression was determined with Western blotting. An EMSA was used for nuclear factor kappaB (NF-κB) activity assay. BV (1–5 μg/mL) inhibited growth of lung cancer cells by induction of apoptosis in a dose dependent manner in lung cancer cell lines A549 and NCI-H460. Consistent with apoptotic cell death, expression of DR3 and DR6 was significantly increased. However, deletion of DRs by small interfering RNA significantly reversed BV induced cell growth inhibitory effects. Expression of pro-apoptotic proteins (caspase-3 and Bax) was concomitantly increased, but the NF-κB activity and expression of Bcl-2 were inhibited. A combination treatment of tumor necrosis factor (TNF)-like weak inducer of apoptosis, TNF-related apoptosis-inducing ligand, docetaxel and cisplatin, with BV synergistically inhibited both A549 and NCI-H460 lung cancer cell growth with further down regulation of NF-κB activity. These results show that BV induces apoptotic cell death in lung cancer cells through the enhancement of DR3 expression and inhibition of NF-κB pathway.
PMCID: PMC4147578  PMID: 25068924
bee venom; apoptosis; death receptors; NF-κB
20.  Non-canonical Autophagy Promotes the Visual Cycle 
Cell  2013;154(2):365-376.
Phagocytosis and degradation of photoreceptor outer segments (POS) by the retinal pigment epithelium (RPE) is fundamental to vision. Autophagy is also responsible for bulk degradation of cellular components but its role in POS degradation is not well understood. We report that the morning burst of RPE phagocytosis coincided with the enzymatic conversion of autophagy protein LC3 to its lipidated form. LC3 then associated with single membrane phagosomes containing engulfed POS in an Atg5 dependent manner that required Beclin1 but not the autophagy pre-initiation complex. The importance of this process was verified in mice with Atg5-deficient RPE cells that showed evidence of disrupted lysosomal processing. These mice also exhibited decreased photoreceptor responses to light stimuli and decreased chromophore levels that were restored with exogenous retinoid supplementation. These results establish that the interplay of phagocytosis and autophagy within the RPE are required for both POS degradation and the maintenance of retinoid levels to support vision.
PMCID: PMC3744125  PMID: 23870125
21.  USP8 is a novel target for overcoming gefitinib-resistance in lung cancer 
Common treatment modalities for non-small cell lung cancer (NSCLC) involve the epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) like gefitinib and erlotinib. However, the vast majority of treated patients acquire resistance to EGFR-TKIs, due in large part to secondary mutations in EGFR or amplification of the MET gene. Our purpose was to test ubiquitin-specific peptidase 8 (USP8) as a potential therapeutic target for gefitinib-resistant and -sensitive non-small cell lung cancer (NSCLC).
Testing the effect of knockdown of USP8 and use of a synthetic USP8 inhibitor to selectively kill gefitinib-resistant (or -sensitive) NSCLCs with little effect on normal cells in cell culture and a xenograft mouse model.
Knockdown of ubiquitin-specific peptidase 8 (USP8) selectively kills gefitinib-resistant NSCLCs, while having little toxicity toward normal cells. Genetic silencing of USP8 led to the down-regulation of several receptor tyrosine kinases (RTKs), including EGFR, ERBB2, ERBB3, and MET. We also determined that a synthetic USP8 inhibitor markedly decreased the viability of gefitinib-resistant and -sensitive NSCLC cells by decreasing RTK expression, while having no effect on normal cells. Moreover, treatment with a USP8 inhibitor led to significant reductions in tumor size in a mouse xenograft model using gefitinib-resistant and -sensitive NSCLC cells.
Our results demonstrate for the first time that the inhibition of USP8 activity or reduction in USP8 expression can selectively kill NSCLC cells. We propose USP8 as a potential therapeutic target for gefitinib-resistant and -sensitive NSCLC cells.
PMCID: PMC3891300  PMID: 23748694
USP8; selective killing; gefitinib-resistance; lung cancer; receptor tyrosine kinases
22.  Molecular Regulation of Sexual Preference Revealed by Genetic Studies of 5-HT in the Brain of Male Mice 
Nature  2011;472(7341):95-99.
To whom should a male directs his mating? While it is a critical social interaction, little is known about molecular and cellular mechanisms controlling mammalian sexual preference. Here we report that the neurotransmitter 5-HT is required for male sexual preference. Male mice lacking central serotonergic neurons lost sexual preference but were not generally defective in olfaction. A role for 5-hydroxytryptamine (5-HT) was demonstrated by the phenotype of mice unable to synthesize 5-HT in the brain when lacking tryptophan hydroxylase 2 (Tph2). 5-hydroxytryptophan (5-HTP) injection rescued the phenotype of adult Tph2 knockout mice within 35 minutes. These results indicate that 5-HT and serotonergic neurons in the adult brain regulate mammalian sexual preference.
PMCID: PMC4094133  PMID: 21441904
23.  Genotoxicity evaluation of Guibi-Tang extract using an in vitro bacterial reverse mutation assay, chromosome aberration assay, and in vivo micronucleus test 
Guibi-Tang is a traditional herbal prescription made from 12 different herbs that is used in the treatment of amnesia and poor memory.
In the present study, we evaluated the acute oral toxicity and genotoxic potential of Guibi-Tang water extract (GBT) at doses up to 2000 μg/plate an using a bacterial reverse mutation test (Ames test) with Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537, and Escherichia coli strain WP2uvrA. Acute toxicity and genotoxic potential were measured in the presence and absence of an exogenous source of metabolic activation, in an in vitro chromosome aberration assay with Chinese hamster lung (CHL) cells, and in an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Food and Drug Administration. An acute oral toxicity test of GBT was performed in Sprague Dawley rats. The Ames test showed that GBT did not induce gene mutations in S. typhimurium or in E. coli in the presence or absence of S9 activation.
GBT did not significantly increase the number of structural aberrations in CHL cells with or without S9 activation. The oral administration of GBT at a dose of up to 2000 mg/kg caused no significant increase in the number of micronucleated polychromatic erythrocytes or in the mean ratio of polychromatic to total erythrocytes.
However, as we did not identify the components of GBT responsible for these effects, other assays are needed to confirm its genotoxicity.
PMCID: PMC4094639  PMID: 24985139
Guibi-tang; Ames test; Chromosome aberration assay; Micronucleus; Genotoxic
24.  Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm) 
Toxicological Research  2014;30(2):121-130.
The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.
PMCID: PMC4112063  PMID: 25071922
Edible insect; Genotoxicity; Repeated dose toxicity; Tenebrio molitor larvae
25.  Significant gastrointestinal morbidity after sacrocolpopexy: The incidence and risk factors 
Obstetrics & Gynecology Science  2014;57(4):304-309.
This study aimed to quantify the risk of significant gastrointestinal (GI) morbidity after sacrocolpopexy (SCP), and to identify related risk factors.
A retrospective study was performed of 258 patients who underwent laparotomic SCP for symptomatic pelvic organ prolapse (POP) from November 2008 to August 2013. By the review of medical records, the frequency of significant GI morbidity that resulted in a prolonged initial hospitalization, readmission, or reoperation was assessed. Thereafter, risk factors for significant GI morbidity were assessed using univariate and multivariate analyses.
Ten patients (3.9%) were identified as having significant GI morbidity; nine (3.5%) had a prolonged initial hospital stay or were readmitted for the medical treatment of postoperative ileus and 1 (0.4%) underwent reoperation for small bowel obstruction. The occurrence of significant GI morbidity was significantly associated with patient's age and prior laparotomy. By multivariable logistic regression analysis, age (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.01-1.27; P=0.03) and prior laparotomy (OR, 6.82; 95% CI, 1.37-34.07; P=0.02) were found as independent risk factors for significant GI morbidity.
One in 25 (3.9%) women after SCP experiences significant GI morbidity. Particularly, women with older age and prior laparotomy have a higher risk for significant GI morbidity. This data will aid preoperative counseling for Korean POP patients undergoing SCP.
PMCID: PMC4124092  PMID: 25105104
Gastrointestinal morbidity; Pelvic organ prolapse; Prior laparotomy; Risk factors; Sacrocolpopexy

Results 1-25 (147)