143 research outputs found

    Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    Get PDF
    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0?? to 45?? and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness.open211

    Neuroinflammation and Neurodegeneration in Adult Rat Brain from Binge Ethanol Exposure: Abrogation by Docosahexaenoic Acid

    Get PDF
    Evidence that brain edema and aquaporin-4 (AQP4) water channels have roles in experimental binge ethanol-induced neurodegeneration has stimulated interest in swelling/edema-linked neuroinflammatory pathways leading to oxidative stress. We report here that neurotoxic binge ethanol exposure produces comparable significant effects in vivo and in vitro on adult rat brain levels of AQP4 as well as neuroinflammation-linked enzymes: key phospholipase A2 (PLA2) family members and poly (ADP-ribose) polymerase-1 (PARP-1). In adult male rats, repetitive ethanol intoxication (3 gavages/d for 4 d, ∼ 9 g/kg/d, achieving blood ethanol levels ∼ 375 mg/dl; Majchrowicz model) significantly increased AQP4, Ca+2-dependent PLA2 GIVA (cPLA2), phospho-cPLA2 GIVA (p-cPLA2), secretory PLA2 GIIA (sPLA2) and PARP-1 in regions incurring extensive neurodegeneration in this model--hippocampus, entorhinal cortex, and olfactory bulb--but not in two regions typically lacking neurodamage, frontal cortex and cerebellum. Also, ethanol reduced hippocampal Ca+2-independent PLA2 GVIA (iPLA2) levels and increased brain oxidative stress footprints (4-hydroxynonenal-adducted proteins). For in vitro studies, organotypic cultures of rat hippocampal-entorhinocortical slices of adult age (∼ 60 d) were ethanol-binged (100 mM or ∼ 450 mg/dl) for 4 d, which augments AQP4 and causes neurodegeneration (Collins et al. 2013). Reproducing the in vivo results, cPLA2, p-cPLA2, sPLA2 and PARP-1 were significantly elevated while iPLA2 was decreased. Furthermore, supplementation with docosahexaenoic acid (DHA; 22:6n-3), known to quell AQP4 and neurodegeneration in ethanol-treated slices, blocked PARP-1 and PLA2 changes while counteracting endogenous DHA reduction and increases in oxidative stress footprints (3-nitrotyrosinated proteins). Notably, the PARP-1 inhibitor PJ-34 suppressed binge ethanol-dependent neurodegeneration, indicating PARP upstream involvement. The results with corresponding models support involvement of AQP4- and PLA2-associated neuroinflammatory pro-oxidative pathways in the neurodamage, with potential regulation by PARP-1 as well. Furthermore, DHA emerges as an effective inhibitor of these binge ethanol-dependent neuroinflammatory pathways as well as associated neurodegeneration in adult-age brain

    Efficacy and Long-Term Follow Up of Combination Therapy with Interferon Alpha and Ribavirin for Chronic Hepatitis C in Korea

    Get PDF
    Combination therapy with interferon alpha (IFN-α) and ribavirin for 24 or 48 weeks according to HCV genotype has improved the overall sustained virological response (SVR) rates to approximately 40%. The aim of this study was to investigate the long-term efficacy of combination therapy with IFN-α and ribavirin for chronic hepatitis C in Koreans. One hundred thirty-eight patients with chronic hepatitis C who received this combination therapy between 1995 and 2003 were analyzed retrospectively. All patients were treated with IFN-α 3-6 million units three times weekly in combination with 900-1200 mg/day of ribavirin for 24 weeks. The overall SVR rate was 41.3%. Patients were followed up for a median of 41 months (range, 12-105 months) after completion of therapy. In all of the SVR patients (57 patients), SVR was conserved during the follow-up period. None of the patients progressed to decompensated liver disease or hepatocellular carcinoma (HCC). However, 5 of the 81 non-SVR patients (6.2%) progressed to decompensated liver disease or HCC. In conclusion, combination therapy with IFN-α and ribavirin shows good long-term efficacy in patients with chronic hepatitis C in Korea, one of the highest endemic areas of hepatitis B virus (HBV) infection

    Comparison of Operative Mortality and Complications between Bronchoplastic Lobectomy and Pneumonectomy in Lung Cancer Patients

    Get PDF
    Bronchoplastic lobectomy is a lung-saving procedure indicated for central tumors, for which the alternative is pneumonectomy. We compared operative mortality and complications between bronchoplastic lobectomy and pneumonectomy in lung cancer patients. From March 1993 through December 2005, 1,461 patients were surgically resected for non-small cell lung cancer, including 73 who underwent bronchoplastic lobectomy and 258 who underwent pneumonectomy. Bronchoplastic lobectomy was performed on any lesion that could be completely resected by this technique, whereas pneumonectomy was only performed on lesions that could not be removed by bronchoplastic lobectomy. Operative deaths occurred in 1 of 73 (1.4%) bronchoplastic lobectomy and 26 of 258 (10.1%) pneumonectomy patients (p=0.014). Major complications occurred in 16 of 73 (21.9%) bronchoplastic lobectomy and 58 of 258 (22.5%) pneumonectomy patients (p=1.0). Bronchoplastic lobectomy has a lower risk of operative mortality than pneumonectomy. Although the complication rates were similar, bronchoplastic lobectomy was associated with improved postoperative cardiopulmonary status and a low prevalence of fatal complications after bronchial anastomosis. These findings indicate that bronchoplastic lobectomy is a valuable alternative to pneumonectomy for anatomically appropriate patients, regardless of underlying cardiopulmonary function

    Comparison of Rifaximin and Lactulose for the Treatment of Hepatic Encephalopathy: A Prospective Randomized Study

    Get PDF
    Rifaximin has been reported to be effective for the treatment of hepatic encephalopathy (HE) in Europe. However, it is unknown whether Rifaximin is effective for the treatment of HE in Koreans, therefore we conducted a open-label prospective randomized study to evaluate the efficacy of rifaximin versus lactulose in Korean patients. Fifty-four patients with liver cirrhosis and hepatic encephalopathy were enrolled. Thirty-two patients were randomized to receive rifaximin and 22 to receive lactulose both over a 7-day periods. Before and at the end of treatment, gradation of blood ammonia, flapping tremor, mental status, number connection test (NCT) were performed and estimation of HE indexes determined. Both rifaximin and lactulose were effective in the majority of patients (84.4% and 95.4%, respectively, p=0.315). Blood NH3, flapping tremor, mental status, and NCT was significantly improved by rifaximin and lactulose, and the posttreatment levels of these measures were similar for the rifaximin and lactulose-treated groups, as was the HE index (rifaximin group (10.0→4.2, p=0.000); lactulose group (11.3→5.0, p=0.000)). One patient treated with rifaximin complained of abdominal pain, which was easily controlled. There was no episode of renal function impairment in either treatment group. Rifaximin proved to be as safe and as effective as lactulose for the treatment of Korean patients with hepatic encephalopathy

    A Case of Stenotic Change from Gastric Candidiasis Managed with Temporary Stent Insertion

    Get PDF
    Invasive gastric Candida infection in patient with co-morbidity can cause stenotic change if it is developed at anatomically narrowing portion, such as distal antrum, pylorus, or duodenal bulb. However, proper management of benign stenosis by diffuse gastric Candidasis is still under controversy and palliative bypass surgery has several shortcomings because high risk operative group may be included in this case. Palliative placement of self-expandable metallic stent has been settled as a standard management of malignant gastric pyloric obstruction and it is expected to be applied in benign stenotic lesions due to its gradual dilation effect. We described a case of stenosis by diffuse gastric Candidasis at anastomosis of subtotal gastrectomy, which was managed by temporary placement of self-expandable metallic stent

    Self-reported Smoking and Urinary Cotinine Levels among Pregnant Women in Korea and Factors Associated with Smoking during Pregnancy

    Get PDF
    This study examined urinary cotinine levels and self-reported smoking among pregnant women in Korea and the factors associated with smoking during pregnancy. The subjects were selected from pregnant women who visited 30 randomly sampled obstetric clinics and prenatal care hospitals in Korea in 2006. Smoking status was determined by self-reporting and urinary cotinine measurement. A total of 1,090 self-administered questionnaires and 1,057 urine samples were analyzed. The percentage of smoking revealed by self-reporting was 0.55% (95% confidence interval [CI], 0.11-0.99) and that revealed by urinary cotinine measurement (>100 ng/mL) was 3.03% (95% CI, 1.99-4.06). The kappa coefficient of agreement between self-reported smoking status and urinary cotinine measurement was 0.20 (95% CI, 0.03-0.37). Multiple logistic regression analysis revealed that early gestational period, low educational level, and being married to a smoker were significant risk factors for smoking during pregnancy. Smoking among pregnant women in Korea is not negligible, and those who are concerned to maternal and child health should be aware of this possibility among pregnant women in countries with similar cultural background

    Efficient production of d-lactate from methane in a lactate-tolerant strain of Methylomonas sp. DH-1 generated by adaptive laboratory evolution

    Get PDF
    Background Methane, a main component of natural gas and biogas, has gained much attention as an abundant and low-cost carbon source. Methanotrophs, which can use methane as a sole carbon and energy source, are promising hosts to produce value-added chemicals from methane, but their metabolic engineering is still challenging. In previous attempts to produce lactic acid (LA) from methane, LA production levels were limited in part due to LA toxicity. We solved this problem by generating an LA-tolerant strain, which also contributes to understanding novel LA tolerance mechanisms. Results In this study, we engineered a methanotroph strain Methylomonas sp. DH-1 to produce d-lactic acid (d-LA) from methane. LA toxicity is one of the limiting factors for high-level production of LA. Therefore, we first performed adaptive laboratory evolution of Methylomonas sp. DH-1, generating an LA-tolerant strain JHM80. Genome sequencing of JHM80 revealed the causal gene watR, encoding a LysR-type transcription factor, whose overexpression due to a 2-bp (TT) deletion in the promoter region is partly responsible for the LA tolerance of JHM80. Overexpression of the watR gene in wild-type strain also led to an increase in LA tolerance. When d form-specific lactate dehydrogenase gene from Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 was introduced into the genome while deleting the glgA gene encoding glycogen synthase, JHM80 produced about 7.5-fold higher level of d-LA from methane than wild type, suggesting that LA tolerance is a critical limiting factor for LA production in this host. d-LA production was further enhanced by optimization of the medium, resulting in a titer of 1.19 g/L and a yield of 0.245 g/g CH4. Conclusions JHM80, an LA-tolerant strain of Methylomonas sp. DH-1, generated by adaptive laboratory evolution was effective in LA production from methane. Characterization of the mutated genes in JHM80 revealed that overexpression of the watR gene, encoding a LysR-type transcription factor, is responsible for LA tolerance. By introducing a heterologous lactate dehydrogenase gene into the genome of JHM80 strain while deleting the glgA gene, high d-LA production titer and yield were achieved from methane.This work was supported by C1 Gas Refnery Program through the National Research Foundation of Korean (NRF) funded by the Ministry of Science and ICT (2016M3D3A01913245)

    Elucidation of Akkermansia muciniphila Probiotic Traits Driven by Mucin Depletion

    Get PDF
    Akkermansia muciniphila is widely considered a next-generation beneficial microbe. This bacterium resides in the mucus layer of its host and regulates intestinal homeostasis and intestinal barrier integrity by affecting host signaling pathways. However, it remains unknown how the expression of genes encoding extracellular proteins is regulated in response to dynamic mucosal environments. In this study, we elucidated the effect of mucin on the gene expression and probiotic traits of A. muciniphila. Transcriptome analysis showed that the genes encoding most mucin-degrading enzymes were significantly upregulated in the presence of mucin. By contrast, most genes involved in glycolysis and energy metabolic pathways were upregulated under mucin-depleted conditions. Interestingly, the absence of mucin resulted in the upregulation of 79 genes encoding secreted protein candidates, including Amuc-1100 as well as members of major protein secretion systems. These transcript level changes were consistent with the fact that administration of A. muciniphila grown under mucin-depleted conditions to high-fat diet-induced diabetic mice reduced obesity and improved intestinal barrier integrity more efficiently than administration of A. muciniphila grown under mucin-containing conditions. In conclusion, mucin content in the growth medium plays a critical role in the improvement by A. muciniphila of high-fat diet-induced obesity, intestinal inflammation, and compromised intestinal barrier integrity related to a decrease in goblet cell density. Our findings suggest the depletion of animal-derived mucin in growth medium as a novel principle for the development of A. muciniphila for human therapeutics

    Hepatitis B Viral Surface Mutations in Patients with Adefovir Resistant Chronic Hepatitis B with A181T/V Polymerase Mutations

    Get PDF
    The hepatitis B virus (HBV) polymerase gene has overlapping reading frames with surface genes, which allows to alter the amino acid codon of the surface genes. In adefovir (ADV) treated chronic hepatitis B patients carrying rtA181T/rtA181V mutations, overlap with surface gene mutations such as sW172stop/sL173F has been reported. However, the clinical consequences of such surface mutations have not been determined. The aim of this study was to determine the surface gene sequence in ADV-resistant patients carrying the A181T/V mutation and to describe the clinical significance. Of the 22 patients included in this study, 13 were ADV-resistant with rtA181T/V mutations (polymerase mutation group, Group P) and nine were antiviral treatment-naïve (control group, Group C). The Pre-S1 gene mutation, V60A, was detected in 11 patients (Group P=8, Group C=3). A start codon mutation in the Pre-S2 gene was found in five patients (Group P=3, Group C=2). An S gene mutation, sA184V, was found in nine patients, all of whom were in group P. Although sW172stop and sL173F mutations were detected, reduced HBsAg titer was not observed. Further study of these mutations and their clinical implications are needed
    corecore