Characteristics of Norovirus Food Poisoning Outbreaks in Korea in the 2000s.

ABSTRACT: Norovirus food poisoning outbreaks in Korea (South) appeared in the 2000s and have been increasing since then. We aimed to investigate the epidemiological features of norovirus food poisoning outbreaks in Korea from 2002 to 2017, on the basis of official food poisoning statistics and publically reliable reports, and to find any associations with climate factors. Norovirus was the most common cause of food poisoning among known causative substances in Korea during the study period. More than one-third of the outbreaks occurred in group meal service facilities, including school lunch programs. A few of these facilities used groundwater contaminated with noroviruses to wash or cook food, which contributed to outbreaks. Norovirus occurrences showed strong seasonality: cold and relatively dry winter air may help norovirus to flourish. Both norovirus genotypes GI and GII that are infectious to humans were detected, with GII becoming more prevalent than GI. According to our correlation analysis in connection with climate factors, average temperatures, the highest and lowest temperatures, precipitation, the number of rain days, and humidity showed a significant negative correlation with a monthly norovirus occurrence (P < 0.05). The lowest temperature and average temperature had higher coefficients of correlation, -0.377 and -0.376, respectively. The norovirus outbreaks in Korea showed complex etiological characteristics, although more prevailed in wintertime, and are now a major public health problem. The use of groundwater in group meal service settings is a public health issue, as well as a norovirus concern; therefore, groundwater used in food service facilities and businesses should be treated for safety.

Detection of Dimethyl Methylphosphonate (DMMP) Using Polyhedral Oligomeric Silsesquioxane (POSS).

The detection and monitoring of colorless and odorless chemical warfare agents (CWAs) has become important due to the increasing threat of terrorist activities. To enhance the sensitivity and selectivity of CWAs a number of sensing materials have been developed, including the widely used polyvinylidene fluoride (PVDF). However, PVDF is limited by its low sensitivity and selectivity for many CWAs. In this study, polyhedral oligomeric silsesquioxane (POSS) was used as a sensing material for dimethyl methylphosphonate (DMMP) a simulant of sarin nerve gas. Sensitivity, selectivity, and reusability were investigated with an AT-cut 5 MHz quartz crystal microbalance. At room temperature, POSS exhibited a strong response for DMMP vapor at different concentrations from 20 ppm to 120 ppm leading to fast chemical adsorption and desorption. To investigate selectivity the volatile organic compounds (VOCs) ethanol, water, toluene, ACN, methanol, and n-hexane were tested at a fixed flow rate. Targeted VOCs showed lower responses than DMMP as measured with a quartz crystal microbalance (QCM) sensor, demonstrating the high selectivity of the method. POSS can be considered a potentially useful material for sensing nerve simulants.

Structural and Morphological Evolution for Water-resistant Organic Thermoelectrics.

We systematically investigated the effect of 2,5-bis(2-hydroxy-3-methacryloyloxypropoxy)-1,4:3,6-dianhydro-sorbitol (Iso-GMA) with different concentrations on the structural and morphological evolution of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) containing a fixed volume of dimethyl sulfoxide (DMSO) to realize water-resistant organic thermoelectric devices. As an additive, Iso-GMA is a hydrophilic and crosslinking agent that can interact with PEDOT and PSS chains by hydrogen bonding and/or dipole-dipole- or dipole-charge-interaction. The Seebeck coefficient and power factor in the film incorporating 3.0 vol% DMSO and 0.8 vol% Iso-GMA were respectively 1.82 × 102 and 1.53 × 105% higher than those of the pristine PEDOT:PSS film without additives (DMSO and Iso-GMA). These results can be attributed to the self-assembled and crosslinked fibril networks with optimized phase separation, where the film has densely-packed PEDOT and highly lamellar-stacked PSS. Also, the reduced charge carrier concentration from the structural characteristics originated in the higher thermoelectric properties. We introduced the schematic illustration to understand the chemical bonding among the components and the morphological evolution according to the Iso-GMA concentration. The increased mechanical strength by the interchain stacking degree of PEDOT and the crosslinking of Iso-GMA facilitate the film remained in a water bath for 0.5 h without physical degradation, and sustain the thermoelectric properties during 12 h in humid conditons.

A New Sling Technique in Cervical Radiculopathy Caused by Vertebral Artery Loop Compression.

BACKGROUND: A 52-year-old woman had a 20-month history of progressive radiating pain in the left arm and numbness on C7 dermatome. CASE DESCRIPTION: On physical examination, left head rotation aggravated the radiculopathic pain. For an anatomic diagnosis of the vertebral artery and nerve root, magnetic resonance angiography was performed (computed tomography angiography was not possible because of her dye allergy history). Magnetic resonance angiography showed a left vertebral artery loop entering at the C6-7 intervertebral foramen. Surgical microvascular decompression was performed by an anterior cervical approach and the loop of the artery was fixed using a sling technique. Postoperative computed tomography angiography showed that the left vertebral artery was retracted anteriorly and the C7 nerve root was decompressed in the intervertebral foramen at the left C6-7 level. CONCLUSIONS: The patient's radiculopathic symptoms were improved and especially the aggravated pain by left head rotation subsided dramatically.

Comparison of the Multidetector-row Computed Tomographic Angiography Axial and Coronal Planes' Usefulness for Detecting Thoracodorsal Artery Perforators.

BACKGROUND: During the planning of a thoracodorsal artery perforator (TDAP) free flap, preoperative multidetector-row computed tomographic (MDCT) angiography is valuable for predicting the locations of perforators. However, CT-based perforator mapping of the thoracodorsal artery is not easy because of its small diameter. Thus, we evaluated 1-mm-thick MDCT images in multiple planes to search for reliable perforators accurately. METHODS: Between July 2010 and October 2011, 19 consecutive patients (13 males, 6 females) who underwent MDCT prior to TDAP free flap operations were enrolled in this study. Patients ranged in age from 10 to 75 years (mean, 39.3 years). MDCT images were acquired at a thickness of 1 mm in the axial, coronal, and sagittal planes. RESULTS: The thoracodorsal artery perforators were detected in all 19 cases. The reliable perforators originating from the descending branch were found in 14 cases, of which 6 had transverse branches. The former were well identified in the coronal view, and the latter in the axial view. The location of the most reliable perforators on MDCT images corresponded well with the surgical findings. CONCLUSIONS: Though MDCT has been widely used in performing the abdominal perforator free flap for detecting reliable perforating vessels, it is not popular in the TDAP free flap. The results of this study suggest that multiple planes of MDCT may increase the probability of detecting the most reliable perforators, along with decreasing the probability of missing available vessels.

Absorbable plate as a perpendicular strut for acute saddle nose deformities.

BACKGROUND: Nasal pyramid fractures accompanied by saddle nose deformities are not easily corrected by closed reduction. We used an absorbable plate as a perpendicular strut to support the collapsed "keystone area" and obtained good results. METHODS: Between September 2008 and June 2011, 18 patients who had nasal pyramid fractures with saddle nose deformities underwent surgery. Pre- and postoperative facial computed tomographic images and photographs were taken to estimate outcomes. The operative technique included the mucoperichondrial dissection of the nasal septum, insertion of an absorbable plate prepared to an appropriate length to support the "keystone area", and fixation of the absorbable plate strut to the cartilaginous septum. RESULTS: Functional and esthetic outcomes were satisfactory in all patients. Eleven patients assessed the postoperative appearance of the external nose as 'markedly improved' and 7 patients as 'improved'. The 5 surgeons scored the results as a mean of 4.5 on a 5-point scale. CONCLUSIONS: The use of an absorbable plate as a perpendicular strut requires no additional procedures because the plate is gradually absorbed. The mechanical strength provided by a buttress between the "keystone area" and the maxillary crest lasts for a long time before the strut is absorbed.

A facile and simple method for the preparation of copoly(TEAMPS/VP)/silver nanocomposites for the humidity-sensing membranes.

We developed a simple method for the preparation of polyelectrolyte/silver nanocomposites, where silver nanoparticles were dispersed in a polyelectrolyte. Copoly(TEAMPS/VP)/silver (w/w=100/0, 100/1, 100/2, 100/3 and 100/4) nanocomposites were obtained by a thermal decomposition reaction of silver carbamate complex at 130 degrees C, and well-dispersed silver colloids were stabilized by copolymer of tetraethylammonium 2-acrylamido-2-methyl-1-propanesulfonate (TEAMPS) and N-vinylpyrrolidone (VP). A dark brown solution in its UV-vis absorption spectrum showed surface plasmon resonance absorption bands at 420 nm in solution. The silver precursor and the resulting polyelectrolyte/Ag nanocomposite was characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), infrared (IR), transmission electron microscopy (TEM). In addition the humidity-sensing properties using copoly(TEAMPS/VP)/Ag nanocomposite films were examined.

Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study.

OBJECTIVE: We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. MATERIALS AND METHODS: The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group ll was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. RESULTS: Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms (p < 0.001). A significant difference was also found between group III and IV for both phantoms (p < 0.001). CONCLUSION: The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body.

Antigenotoxic effects of water extract from Korean fermented soybean paste (doen-jang).

Aflatoxin B1 is a major metabolite of the toxigenic molds Aspergillus flavus and Aspergillus parasiticus. In this study, a bacterial reverse mutation assay with Salmonella Typhimurium strains TA1535, TA1537, TA98, TA100, and TA102 and an in vitro chromosome aberration test with Chinese hamster lung (CHL) cells were used to investigate the genotoxicity of water extract from Korean soybean paste (doen-jang [dwen-jahng]) and its antigenotoxic activity against aflatoxin B1. The water extract itself did not exhibit cytotoxicity or mutagenicity. The extract significantly reduced the numbers of revertants when it was added to the assay system with Salmonella Typhimurium TA100 (P < 0.05). The extract also exhibited significant inhibitory effects on chromosome aberration in CHL cells (P < 0.05). Dose-response relationships were observed between the concentration of the water extract and both its antimutagenic effect and its suppression of chromosome aberration. The results of this work indicate that water extract from Korean soybean paste could have potential as an antigenotoxic substance.

Reduction of aflatoxins by Korean soybean paste and its effect on cytotoxicity and reproductive toxicity--Part 3. Inhibitory effects of Korean soybean paste (doen-jang) on aflatoxin toxicity in laying hens and aflatoxin accumulation in their eggs.

This study was conducted to determine the effects of Korean soybean paste (doen-jang [dwen-jahng]) (at concentrations of 0.5, 1, and 5%) on the toxicity of 500 ppb of aflatoxin in the diets of 60 laying hens (Isa Brown) divided into five groups and treated from week 15 to week 67. The aflatoxin-treated hens exhibited many deleterious effects, including reduced body weight; increased relative organ weights; decreased egg production; aflatoxin accumulation in eggs; decreased serum calcium, phosphorus, and alanino amonotransferase (ALT) levels; increased serum gammaglutamil transferase and lactic dehydrogenase levels; and, most significantly, severely altered cell foci and sinusoid dilatation in the liver, relative to control hens. The feeding of 1% soybean paste to hens reduced the adverse effects of aflatoxin on body weight, relative organ weights, egg production, and aflatoxin accumulation in eggs and improved serum calcium and ALT levels and the histopathological lesions of the liver. The feeding of 5% soybean paste to hens resulted in higher levels of the same types of improvements, especially with regard to the histopathological findings for the liver. On the basis of these results, it was suggested that a diet including 5% (and in some cases only 1%) Korean soybean paste protected laying hens and their eggs from the major deleterious effects of 500 microg of aflatoxin per kg of diet and from aflatoxin accumulation. These results indicate that dietary supplementation with Korean soybean paste reduces aflatoxin toxicity in laying hens that ultimately produce human foods such as eggs and poultry.

Reduction of aflatoxins by Korean soybean paste and its effect on cytotoxicity and reproductive toxicity--part 2. Antigenotoxic effects of the methanol extract of Korean soybean paste (doen-jang) on aflatoxin B1-induced bacterial reverse mutation and chromosome aberration.

A bacterial reverse-mutation assay with Salmonella Typhimurium TA1535, TA1537, TA98, TA100, and TA102 and an in vitro chromosome aberration assay with Chinese hamster lung (CHL) cells were used to investigate the genotoxicity of the methanol extract of Korean soybean paste (doen-jang [dwen-jahng]) and its antigenotoxic activity against aflatoxin B1. The methanol extract revealed nonmutagenic potential for all of the bacterial strains tested. The extract significantly reduced the numbers of revertants per plate when it was added to the assay system with Salmonella Typhimurium TA100 (P < 0.05). The extract also exhibited significant inhibitory effects on chromosome aberration in CHL cells (P < 0.05). The findings of this work indicate that the methanol extract of Korean soybean paste could have strong potential as an antigenotoxic material.

Grain Development and Aflatoxin B1 Accumulation in Preharvest Rice Inoculated with Aspergillus parasiticus.

A rice cultivar (Japonica type), Cheong-cheong , was planted in a rice paddy in Southern Korea to examine the effects of Aspergillus parasiticus infection on the development of the grains. The grain was inoculated with the fungal inoculum at the milk stage of development. Ripening rates, 100-grain weights and aflatoxin B1 accumulation were observed at harvest. An enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining were performed to detect and confirm aflatoxin B1 in the samples. When the rice grains were inoculated with A. parasiticus the ripening rates (number of fully matured grains per total number of grains in a panicle) were not significantly different from the control samples. Examination of 100-grain weights showed no significant difference between the groups. The edible portion of inoculated grain exhibited significantly higher levels of toxins than did the rice hulls, and the embryo contained a higher proportion of toxins than the endosperm (P < 0.05). The immunohistochemical staining revealed positive findings for the embryo of inoculated grains, but not for the control embryo.