Doxifluridine versus Tegafur/Gimeracil/Oteracil (S-1) as adjuvant chemotherapy for patients with gastric cancer after gastrectomy: A propensity score-matched analysis.

INTRODUCTION: Doxifluridine (DF), an oral 5-FU prodrug, has been used for various solid cancers due to its efficacy and low toxicity. We aim to evaluate the effect of DF as adjuvant monotherapy in advanced gastric cancer. METHODS: We retrospectively reviewed the clinical data of 263 patients with advanced gastric cancer who underwent curative gastrectomy between January 2010 and December 2013 at our institute. Since previous randomized control trials have confirmed the efficacy of S-1 as adjuvant chemotherapy in advanced gastric cancer, we analyzed the oncologic effect and patient compliance of the DF group compared to the S-1 group. After propensity score matching, 48 patients were included in each group. RESULTS: There was no significant difference in 5-year overall survival (OS) and 5-year disease-free survival (DFS) between DF and S-1 groups (5-year OS; 77.1% vs 75.0%; p = 0.729, 5-year DFS; 76.6% vs 73.9%; p = 0.748). The completion rates of the DF and S-1 groups were 60.4% and 72.9%, respectively (p = 0.194). The mean relative dose intensity of the DF and S-1 groups were 76.2% and 84.2%, respectively (p = 0.195). After multivariate analysis, the chemotherapy regimen was not a risk factor for OS and DFS, whereas relative dose intensity and pathologic stage were independent prognostic factors. CONCLUSION: There was no significant difference in the oncologic effect and patient compliance between DF and S-1 groups. DF could be an alternative option for adjuvant chemotherapy in advanced gastric cancer. In addition, we confirmed that relative dose intensity is an important independent prognostic factor for survival.

A novel statistical-dynamical method for a seasonal forecast of particular matter in South Korea.

Societal concerns about air quality in East Asia are still growing despite country-level efforts to reduce air pollution emissions. In coping with this growing concern, the government and the public demand a longer­lead forecast of air quality to ensure sufficient response time until society prepares for countermeasures such as a temporary reduction of specific emission sources. Here we propose a novel method that produces skillful seasonal forecasting of wintertime (December to February) PM10 concentration over South Korea. The method is based on the idea that climate condition and air quality have co-variability in the seasonal time scales and that the state-of-art seasonal prediction model will benefit air quality forecasting. More specifically, a linear regression model is constructed to link observed winter PM10 concentration and climate variables where the predicted climate variables were furnished from NCEP CFSv2 forecast initialized during autumn. In this case, climate variables were selected as predictors of the model because they are not only physically related to air quality but also 'predictable' in CFS hindcast. Through analysis of retrospective forecasts of 20 winters for the period 2001-2020, we found this model shows statistically significant skill for the seasonal forecast of wintertime PM10 concentration.

Dual Electrorheological and Magnetorheological Behaviors of Poly(N-methyl aniline) Coated ZnFe2O4 Composite Particles.

Magnetic/conducting polymeric hybrid core-shell typed zinc ferrite (ZnFe2O4)/poly(N-methyl aniline) (PMA) particles were fabricated and adopted as electrorheological (ER) and magnetorheological (MR) fluids, and their rheological properties were examined. Solvo-thermally synthesized ZnFe2O4 was coated with a conducting PMA through chemical oxidation polymerization. The size, shape, and chemical composition of the final core-shell shaped particles were scrutinized by scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy. The crystal faces of the particles before and after coating with PMA were analyzed by X-ray diffraction. The ZnFe2O4/PMA products were suspended in silicone oil to investigate the rheological response to electro- or magnetic stimuli using a rotating rheometer. The shear stresses were analyzed using the CCJ equation. The dynamic yield stress curve was suitable for the conductivity mechanism with a slope of 1.5. When magnetic fields of various intensities were applied, the flow curve was analyzed using the Hershel-Bulkley equation, and the yield stresses had a slope of 1.5. Optical microscopy further showed that the particles dispersed in insulating medium form chain structures under electric and magnetic fields. Via this core-shell fabrication process, not only spherical conducting particles were obtained but also their dual ER and MR responses were demonstrated for their wide potential applications.

Binodal, wireless epidermal electronic systems with in-sensor analytics for neonatal intensive care.

Existing vital sign monitoring systems in the neonatal intensive care unit (NICU) require multiple wires connected to rigid sensors with strongly adherent interfaces to the skin. We introduce a pair of ultrathin, soft, skin-like electronic devices whose coordinated, wireless operation reproduces the functionality of these traditional technologies but bypasses their intrinsic limitations. The enabling advances in engineering science include designs that support wireless, battery-free operation; real-time, in-sensor data analytics; time-synchronized, continuous data streaming; soft mechanics and gentle adhesive interfaces to the skin; and compatibility with visual inspection and with medical imaging techniques used in the NICU. Preliminary studies on neonates admitted to operating NICUs demonstrate performance comparable to the most advanced clinical-standard monitoring systems.

Three-Dimensional Silicon Electronic Systems Fabricated by Compressive Buckling Process.

Recently developed approaches in deterministic assembly allow for controlled, geometric transformation of two-dimensional structures into complex, engineered three-dimensional layouts. Attractive features include applicability to wide ranging layout designs and dimensions along with the capacity to integrate planar thin film materials and device layouts. The work reported here establishes further capabilities for directly embedding high-performance electronic devices into the resultant 3D constructs based on silicon nanomembranes (Si NMs) as the active materials in custom devices or microscale components released from commercial wafer sources. Systematic experimental studies and theoretical analysis illustrate the key ideas through varied 3D architectures, from interconnected bridges and coils to extended chiral structures, each of which embed n-channel Si NM MOSFETs (nMOS), Si NM diodes, and p-channel silicon MOSFETs (pMOS). Examples in stretchable/deformable systems highlight additional features of these platforms. These strategies are immediately applicable to other wide-ranging classes of materials and device technologies that can be rendered in two-dimensional layouts, from systems for energy storage, to photovoltaics, optoelectronics, and others.

Risk assessment principle for engineered nanotechnology in food and drug.

While the ability to develop nanomaterials and incorporate them into products is advancing rapidly worldwide, understanding of the potential health safety effects of nanomaterials has proceeded at a much slower pace. Since 2008, Korea Food and Drug Administration (KFDA) started an investigation to prepare "Strategic Action Plan" to evaluate safety and nano risk management associated with foods, drugs, medical devices and cosmetics using nano-scale materials. Although there are some studies related to potential risk of nanomaterials, physical-chemical characterization of nanomaterials is not clear yet and these do not offer enough information due to their limitations. Their uncertainties make it impossible to determine whether nanomaterials are actually hazardous to human. According to the above mention, we have some problems to conduct the human exposure risk assessment currently. On the other hand, uncertainty about safety may lead to polarized public debate and to businesses unwillingness for further nanotechnology investigation. Therefore, the criteria and methods to assess possible adverse effects of nanomaterials have been vigorously taken into consideration by many international organizations: the World Health Organization, the Organization for Economic and Commercial Development and the European Commission. The object of this study was to develop risk assessment principles for safety management of future nanoproducts and also to identify areas of research to strengthen risk assessment for nanomaterials. The research roadmaps which were proposed in this study will be helpful to fill up the current gaps in knowledge relevant nano risk assessment.

Heavy metal risk management: case analysis.

To prepare measures for practical policy utilization and the control of heavy metals, hazard control related institutions by country, present states of control by country, and present states of control by heavy metals were examined. Hazard control cases by heavy metals in various countries were compared and analyzed. In certain countries (e.g., the U.S., the U.K., and Japan), hazardous substances found in foods (e.g., arsenic, lead, cadmium, and mercury) are controlled. In addition, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) recommends calculating the provisional tolerable weekly intake (PTWI) of individual heavy metals instead of the acceptable daily intake (ADI) to compare their pollution levels considering their toxicity accumulated in the human body. In Korea, exposure assessments have been conducted, and in other countries, hazardous substances are controlled by various governing bodies. As such, in Korea and other countries, diverse food heavy metal monitoring and human body exposure assessments are conducted, and reducing measures are prepared accordingly. To reduce the danger of hazardous substances, many countries provide leaflets and guidelines, develop hazardous heavy metal intake recommendations, and take necessary actions. Hazard control case analyses can assist in securing consumer safety by establishing systematic and reliable hazard control methods.

Lead, cadmium and mercury levels in the 2010 Korean diet.

This study analysed the level of contamination of harmful heavy metals in 3820 food samples available in Korea in 2010. A total of 119 types of samples were collected, including corns, vegetables, fruits, fishes, mollusks, shellfish, crustaceans, seaweed, bean products, meats and eggs from seven major cities. These samples were analysed using ICP-MS after pre-treatment with a microwave-digestion system. Results of lead, cadmium and mercury analyses were compared with the standard specifications of Korea Food Standards Codex. As a result, high levels of Pb, Cd and Hg were detected in "cockle," "dried-squid" and "shark-meat." Acceptable intake for consumers was checked using provisional tolerable weekly intake values. Such results will be utilised as data on the exposure of human body through foods. In addition, satisfactory results were obtained through purchase and analysis of National Institute of Science and Technology-certified reference materials to obtain reliability on analysis results.

Single-step extraction followed by LC for determination of (fluoro)quinolone drug residues in muscle, eggs, and milk.

In this study, a simplified method for the extraction and determination of seven fluoroquinolone residues (danofloxacin, difloxacin, enrofloxacin, marbofloxacin, orbifloxacin, ofloxacin, and sarafloxacin) and three quinolones (oxolinic acid, flumequine, and nalidixic acid), in porcine muscle, table eggs, and commercial whole milk, which required no cleanup step, was devised. This procedure involves the extraction of analytes from the samples via liquid-phase extraction, and the subsequent quantitative determination was accomplished via LC-fluorescence detection. Analyte separation was successfully conducted on an XBridge-C(18) column, with a linear gradient mobile phase composed of acetonitrile and 0.01 M oxalic acid buffer at pH=3.5. The one-step liquid-liquid extraction method evidenced good selectivity, precision (RSDs=0.26-15.07%), and recovery of the extractable analytes, ranging from 61.12 to 115.93% in matrices. The LOQs ranged from 0.3 to 25 microg/kg. A survey of ten samples purchased from local markets was conducted, and none of the samples harbored fluoroquinolone residues. This method is an improvement over existing methodologies, since no additional cleanup was necessary.

Establishment of the korean tolerable daily intake of bisphenol a based on risk assessments by an expert committee.

Recently, reproductive and neurobehavioral effects of bisphenol A (BPA) have been documented, and thus a review was requested for BPA management direction by the government. Therefore, this study was performed to establish a Korean tolerable daily intake (TDI) for BPA. An expert committee, consisting of specialists in fields such as toxicology, medicine, pharmacology, and statistics, was asked to evaluate BPA health based guidance values (HbGVs) . Although many toxicological studies were reviewed to select a point of departure (POD) for TDI, rat and mouse reproductive studies by Tyl et al. (2002, 2006) , which were performed according to GLP standards and OECD guidelines, were selected. This POD was the lowest value determined from the most sensitive toxicological test. The POD, a NOAEL of 5 mg/kg bw/day, was selected based on its systemic toxicity as critical effects. An uncertainty factor of 100 including interspecies and intraspecies differences was applied to calculate the TDI. According to the evaluation results, a TDI of BPA for Korean was suggested at 0.05 mg/kg bw/day. In addition, the BPA exposure level based on food consumption by the Korean population was estimated as 1.509 µg/kg bw/day, and the HI was evaluated at 0.03 when the TDI of 0.05 mg/kg bw/day was applied. This HI value of 0.03 indicated that hazardous effects would not be expected from BPA oral exposures. Although highly uncertain, further studies on low dose neurobehavioral effects of BPA should be performed. In addition, it is recommended that the 'as low as reasonably achievable' (ALARA) principle be applied for BPA exposure from food packaging materials in newborn infants and children.

Simultaneous determination of pyrethroids from pesticide residues in porcine muscle and pasteurized milk using GC.

The principal goal of this work was to develop an efficient method for the simultaneous determination of four pyrethroid (PYR) insecticides, cyfluthrin, cyhalothrin, cypermethrin, and deltamethrin, in porcine muscle and pasteurized milk using liquid-liquid extraction (LLE). Sample extraction was carried out with and without additional column cleanup procedures, and the final determination was made using GC with electron-capture detector (ECD). The pesticide identity was confirmed using GC-MS in the SIM mode. Since there were minor differences between the extraction procedures, extraction without the additional cleanup procedure was used throughout the work. The method was validated by fortifying blank samples with half, two, and four times the maximum residue limit (MRL) of each PYR. The average recoveries (n = 6) ranged from 83.5 to 99.2% and 82.9 to 109% in porcine muscle and pasteurized milk, respectively. The repeatability of measurements expressed as RSDs, was in the range of 1.7-11.9 and 1.5-10.3% in porcine muscle and pasteurized milk, respectively. The LODs ranged from 3.3 to 9 and 3 to 8.1 ppm, whereas the LOQs ranged from 10 to 27.4 and 9 to 24.6 ppm, in porcine muscle and pasteurized milk, respectively. The applicability of the method was demonstrated by analyzing real samples collected from major cities in the Republic of Korea. No residues of the selected pesticides were detected in any of the samples.

Monitoring of fluoroquinolone residual levels in chicken eggs by microbiological assay and confirmation by liquid chromatography.

The primary objective of this study was to develop a simple, rapid, and efficient method for the simultaneous determination of four fluoroquinolone residues, ciprofloxacin (CFX), danofloxacin (DFX), enrofloxacin (EFX) and norfloxacin (NFX), in chicken eggs. The samples were first monitored by microbiological assay using Escherichia coli as the reference organism, and were then quantified using HPLC with a fluorescence detector. Egg samples were extracted by the liquid-phase extraction process, and the analytes were analyzed via an ODS column using a mixture of acetonitrile and 0.4% phosphoric acid-0.4% triethylamine (15: 85, v/v) as a mobile phase (pH=2) without purification. The calibration curves were linear (r2>or=0.999) over a concentration range of 0.1-1.0 microg/mL. The majority of the mean recoveries at four different fortification levels, 0.1, 0.2, 0.5 and 1.0 ppm, ranged from 73.7+/-7.2% to 87.1+/-12.7%, and the repeatability (as the relative standard deviation) from three repetitive determinations of recovery was between 1.03 and 18.83%. The calculated limit of quantitation (LOQ) was 9 ppb for CFX, EFX and NFX and 0.6 ppb for DFX. Both the bioassay and HPLC methods were applied to 120 total egg samples collected from the six major cities in the Republic of Korea. The bioassay, showed that two samples were positive (i.e contained inhibiting substances). On the other hand, the results of HPLC only identified and quantified the residues of enrofloxacin (from 0.43 to 1.02 ppm) in three samples out of 120. We concluded that the bioassay can be used as a routine screening method for the presence of fluoroquinolones in chicken eggs, which can be confirmed and quantified using LC.

[The long-term follow-up results after steroid treatment in patients with autoimmune chronic pancreatitis].

BACKGROUND/AIMS: Autoimmune chronic pancreatitis (AIP) is a clinically attractive entity because of its dramatic response to steroid therapy. But the long-term results after steroid therapy have not been reported yet in Korea. The purpose of this study was to assess the long-term results and prognosis after steroid therapy in patients with AIP. METHODS: We retrospectively analyzed the clinical, radiologic, and laboratory features and evaluated clinical outcomes in 19 patients with AIP who have been treated with oral corticosteroid. All patients were initially treated with prednisolone (30-40 mg/d) for 1 or 2 months. After the confirmation of clinical improvement in radiologic imaging and laboratory findings, the daily dose of prednisolone was then gradually tapered by 5-10 mg per month to the maintenance dose (2.5-7.5 mg/d). RESULTS: All the patients showed normalization or marked improvement in symptoms, laboratory and imaging findings after steroid therapy. There were 4 cases (21%) of recurrence during the mean follow-up period of 27 months. All the patients with recurrence responded to oral steroid again. Among the 10 patients with diabetes mellitus, seven patients were able to stop or reduce the medication for diabetes after completion of steroid therapy. The biliary stents were additionally inserted in 10 patients who showed distal common bile duct stricture and obstructive jaundice. The accompanying autoimmune diseases were also improved with oral corticosteroid. CONCLUSIONS: Steroid therapy is very effective for AIP and is also effective in the cases of recurrence. A definitive protocol of steroid therapy for AIP should be established in the future.