Effectiveness of a Real-Time Ventilation Feedback Device for Guiding Adequate Minute Ventilation: A Manikin Simulation Study.

Background and objectives: It is often challenging even for skilled rescuers to provide adequate positive pressure ventilation consistently. This study aimed to investigate the effectiveness of a newly developed real-time ventilation feedback device (RTVFD) that estimates tidal volume (TV) and ventilation interval (VI) in real time. Materials and methods: We conducted a randomised, crossover, manikin simulation study. A total of 26 medical providers were randomly assigned to the RTVFD-assisted ventilation (RAV) first group (n = 13) and the non-assisted ventilation (NV) first group (n = 13). Participants provided ventilation using adult and paediatric bag valves (BVs) for 2 min each. After a washout period, the simulation was repeated by exchanging the participants' groups. Results: The primary outcome was optimal TV in the RAV and NV groups using adult and paediatric BVs. A secondary outcome was optimal VI in the RAV and NV groups using adult and paediatric BVs. The proportions of optimal TV values were higher for the RAVs when using both adult and paediatric BVs (adult BV: 47.29% vs. 18.46%, p < 0.001; paediatric BV: 89.51% vs. 72.66%, p < 0.001) than for the NVs. The proportions of optimal VI were significantly higher in RAVs when using both adult and paediatric BVs than that in NVs (adult BV: 95.64% vs. 50.20%, p < 0.001; paediatric BV: 95.83% vs. 57.14%, p < 0.001). Additionally, we found that with paediatric BVs, the simulation had a higher OR for both optimal TV (13.26; 95% CI, 9.96-17.65; p < 0.001) and VI (1.32; 1.08-1.62, p = 0.007), regardless of RTVFD use. Conclusion: Real-time feedback using RTVFD significantly improves the TV and VI in both adult and paediatric BVs in a manikin simulation study.

Expansion of Shiga Toxin-Producing Escherichia coli by Use of Bovine Antibiotic Growth Promoters.

Antibiotics are routinely used in food-producing animals to promote growth and prevent infectious diseases. We investigated the effects of bovine antibiotic growth promoters (bAGPs) on the propagation and spread of Shiga toxin (Stx)-encoding phages in Escherichia coli. Co-culture of E. coli O157:H7 and other E. coli isolated from cattle in the presence of sublethal concentrations of bAGPs significantly increased the emergence of non-O157, Stx-producing E. coli by triggering the SOS response system in E. coli O157:H7. The most substantial mediation of Stx phage transmission was induced by oxytetracyline and chlortetracycline, which are commonly used in agriculture. bAGPs may therefore contribute to the expansion of pathogenic Stx-producing E. coli.

Novel adjuvant strategy to potentiate bacitracin against MDR MRSA.

OBJECTIVES: Bacitracin is an antimicrobial peptide that is frequently used as an active ingredient in antimicrobial ointments. However, bacitracin resistance is highly prevalent in community-associated MRSA (CA-MRSA) strains and significantly compromises the effectiveness of existing antimicrobial ointments. In this study, we aimed to develop novel adjuvants to enhance the antimicrobial activity of bacitracin by using alkyl gallates. METHODS: The growth of MRSA USA300, the predominant CA-MRSA strain in the USA, was determined in the presence of bacitracin and alkyl gallates at various concentrations. The viability of USA300 and MDR clinical isolates of MRSA was measured after exposure to various combinations of bacitracin and alkyl gallates. RESULTS: Whereas 100 U/mL bacitracin did not inhibit USA300, 1 U/mL bacitracin in combination with as low as 2 mg/L octyl gallate (OG) and 8 mg/L dodecyl gallate (DG), respectively, completely inhibited the growth of USA300. Among the tested alkyl gallates, OG most significantly enhanced the bactericidal activity of bacitracin. For example, 10(-3) U/mL bacitracin with 5 mg/L OG effectively killed USA300, which is an ∼200 000-fold decrease in the MBC of bacitracin for USA300. Furthermore, bacitracin/OG combinations demonstrated similar levels of antimicrobial activity against human clinical isolates of MRSA resistant to multiple antibiotics of clinical importance. CONCLUSIONS: Some alkyl gallates, particularly OG, significantly increased the antimicrobial activity of bacitracin against MDR MRSA.

Brain inositol is a novel stimulator for promoting Cryptococcus penetration of the blood-brain barrier.

Cryptococcus neoformans is the most common cause of fungal meningitis, with high mortality and morbidity. The reason for the frequent occurrence of Cryptococcus infection in the central nervous system (CNS) is poorly understood. The facts that human and animal brains contain abundant inositol and that Cryptococcus has a sophisticated system for the acquisition of inositol from the environment suggests that host inositol utilization may contribute to the development of cryptococcal meningitis. In this study, we found that inositol plays an important role in Cryptococcus traversal across the blood-brain barrier (BBB) both in an in vitro human BBB model and in in vivo animal models. The capacity of inositol to stimulate BBB crossing was dependent upon fungal inositol transporters, indicated by a 70% reduction in transmigration efficiency in mutant strains lacking two major inositol transporters, Itr1a and Itr3c. Upregulation of genes involved in the inositol catabolic pathway was evident in a microarray analysis following inositol treatment. In addition, inositol increased the production of hyaluronic acid in Cryptococcus cells, which is a ligand known to binding host CD44 receptor for their invasion. These studies suggest an inositol-dependent Cryptococcus traversal of the BBB, and support our hypothesis that utilization of host-derived inositol by Cryptococcus contributes to CNS infection.

Assessment of polychlorinated naphthalenes in Korean foods: Levels, profiles, and dietary intake.

Concerns about dioxin-like compounds have increased; however, the monitoring of polychlorinated naphthalenes (PCNs) in food and the assessment of dietary intake remain limited. In this study, various foods were collected from Korean markets and analyzed for PCNs. Fishery products exhibited the highest mean concentration (48.0 pg/g ww) and toxic equivalent (TEQ) (0.0185 pg-TEQ/g ww). Agricultural products were the largest contributors (35.7%) to the total dietary intake of PCNTEQ, followed by livestock products (33.6%), fishery products (20.2%), and processed foods (10.5%). The mean intake of PCNTEQ for the Korean population was 0.901 pg-TEQ/day for males and 0.601 pg-TEQ/day for females. Generally, males and younger groups had higher daily intakes of PCNTEQ, but they did not exceed the tolerable weekly intakes. Nonetheless, it is important to manage potential health risks associated with PCNs and other dioxin-like compounds by identifying major food items contributing to PCN exposure and considering age and gender differences.

Cryptococcus neoformans activates RhoGTPase proteins followed by protein kinase C, focal adhesion kinase, and ezrin to promote traversal across the blood-brain barrier.

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningoencephalitis. Previous studies have demonstrated that Cryptococcus binding and invasion of human brain microvascular endothelial cells (HBMEC) is a prerequisite for transmigration across the blood-brain barrier. However, the molecular mechanism involved in the cryptococcal blood-brain barrier traversal is poorly understood. In this study we examined the signaling events in HBMEC during interaction with C. neoformans. Analysis with inhibitors revealed that cryptococcal association, invasion, and transmigration require host actin cytoskeleton rearrangement. Rho pulldown assays revealed that Cryptococcus induces activation of three members of RhoGTPases, e.g. RhoA, Rac1, and Cdc42, and their activations are required for cryptococcal transmigration across the HBMEC monolayer. Western blot analysis showed that Cryptococcus also induces phosphorylation of focal adhesion kinase (FAK), ezrin, and protein kinase C α (PKCα), all of which are involved in the rearrangement of host actin cytoskeleton. Down-regulation of FAK, ezrin, or PKCα by shRNA knockdown, dominant-negative transfection, or inhibitors significantly reduces cryptococcal ability to traverse the HBMEC monolayer, indicating their positive role in cryptococcal transmigration. In addition, activation of RhoGTPases is the upstream event for phosphorylation of FAK, ezrin, and PKCα during C. neoformans-HBMEC interaction. Taken together, our findings demonstrate that C. neoformans activates RhoGTPases and subsequently FAK, ezrin, and PKCα to promote their traversal across the HBMEC monolayer, which is the critical step for cryptococcal brain infection and development of meningitis.

Characterization of BNT2, an intrinsically curved DNA of Escherichia coli O157:H7.

The gene regulation by intrinsically curved DNA is one way for bacterial sensing of and response to environmental changes. Previously, we showed that the genetic element BNT2 upstream of the ecf (eae-positive conserved fragment) operon in the Escherichia coli O157:H7 virulence plasmid (pO157) has characteristics typical of intrinsically curved DNA, including the presence of multi-homopolymeric adenine:thymine tracts (AT tracts) and electrophoretic anomaly at 4 degrees C. Here we report that a local intrinsic curvature induced by the two phased AT tracts within the unusual promoter sequence of BNT2 played a major role for its temperature-dependent promoter activity. The base substitution of the AT tract in the spacer DNA between the -35 and the unusual -10 regions of the BNT2 promoter with non-AT tract sequence reduced intrinsic curvature slightly at 4 degrees C, but greatly affected its transcriptional activity. This implies that such a local intrinsic curvature within the unusual promoter of BNT2 is important for thermoregulation of the ecf operon.

Omics-based analysis of the luxS mutation in a clinical isolate of Escherichia coli O157:H7 in Korea.

The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:H7. A non-polar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the DeltaluxS mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally-defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxis-related genes (flhD; fliA, C, D, S, Z; cheA, Y, and Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.

Short-chain chlorinated paraffins in various foods from Republic of Korea: Levels, congener patterns, and human dietary exposure.

Short-chain chlorinated paraffin (SCCP) concentrations in 419 food samples (from 59 species) from Republic of Korea were determined. The SCCP concentrations and lipid contents in whole foods positively correlated and the highest SCCP concentration (891 ng/g wet weight) was observed in fats and oils. The SCCP concentrations were higher in benthic fish/shellfish and demersal fish than other fish and shellfish. The SCCP concentrations were higher in duck meat and eggs than meat and eggs of other species. The chlorine-based congener group patterns were related to the lipid contents of the foods. SCCPs in eggs (high lipid content) were dominated by more-chlorinated SCCPs (particularly Cl8-SCCPs, which contributed 43% of the total) but SCCPs in seaweed (low lipid content) were dominated by less-chlorinated SCCPs (particularly Cl6-SCCPs, which contributed 46%). Dietary SCCP intakes were calculated using the median SCCP concentrations and estimated 888 and 781 ng/kg/d for male and female Korean adults, respectively. The predominant contributing foods to SCCP dietary exposure differed according to sex and age. Dairy products contributed most (about 50%) for infants/children (1-5 y old), but meat and dairy products contributed most for adult males and females, respectively. Grain contributed most for ≥65 y old.

Atmospheric pressure chemical ionization and fragmentation of aminomonosaccharides in H2O and D2O.

Aminomonosaccharides (glucosamine, galactosamine, and mannosamine) in H2O and D2O were ionized by atmospheric pressure chemical ionization (APCI) and their fragmentation patterns were investigated to identify them. All the aminomonosaccharides showed the same fragment ions but their relative ion intensities were different. Major product ions generated in H2O were [M + H]+, [M + H - H2O]+, and [2M + H - 3H2O]+, while in D2O were [M(D6) + D]+, [M(D6) + D - D2O]+, and [2M(D6) + D - D2O - 2HDO]+. At a high fragmentor voltage above 120 V, the relative ion intensities of the major product ions showed different trends according to the aminomonosaccharides. For the use of H2O as solvent and eluent, the order of the ion intensity ratio of [M + H - H2O]+/[2M + H - 3H2O]+ was galactosamine > mannosamine > glucosamine. When using D2O as solvent and eluent, the order of the ion intensity ratios of [M(D6) + D - D2O]+/[MD6 + D]+ and [2M(D6) + D - D2O - 2HDO]+/[M(D6) + D]+ was mannosamine > galactosamine > glucosamine. It was found that glucosamine, galactosamine, and mannosamine could be distinguished by the specific trends of the major product ion ratios in H2O and D2O.

Detection of cytolethal distending toxin and other virulence characteristics of enteropathogenic Escherichia coli isolates from diarrheal patients in Republic of Korea.

Cytolethal distending toxins (CDTs) represent an emerging family of newly described bacterial products that are produced by a number of pathogens. The genes encoding these toxins have been identified as a cluster of three adjacent genes, cdtA, cdtB, and cdtC, plus 5 cdt genetic variants, designated as cdt-I, cdt-II, cdt-III, cdt-IV, and cdt- V, have been identified to date. In this study, a general multiplex PCR system designed to detect Escherichia coli cdts was applied to investigate the presence of cdt genes among isolates. As a result, among 366 E. coli strains, 2.7% were found to carry the cdtB gene. In addition, the use of type-specific primers revealed the presence of cdt-I, cdtIV, and cdt-V types of the cdt gene, yet no cdt-II or cdt- III strains. The presence of other virulence genes (stx1, stx2, eae, bfp, espA, espB, and espD) was also investigated using a PCR assay. Among the 10 cdtB gene-positive strains, 8 were identified as CDT-producing typical enteropathogenic E. coli (EPEC) strains (eae(+), bfp(+)), whereas 2 were identified as CDT-producing atypical EPEC strains (eae(+), bfp(-)). When comparing the cytotoxic activity of the CDT-producing typical and atypical EPEC strains, the CDT-producing atypical EPEC strains appeared to be less toxic than the CDT-producing typical EPEC strains.

Assessment of selected chlorinated and brominated flame retardants in human plasma samples among co-residing family members.

Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs) were measured in 414 human plasma samples, (169 from children, 167 from mothers, and 78 from fathers), collected from 200 families between 2014 and 2016. The median concentration of ∑PBDEs (sum of BDE-47, -99, -100, -153 and -183) was 13.2 ng/g lipid for child, 9.03 ng/g lipid for mother and 12.7 ng/g lipid for father, respectively. Among the hexachloronorbornene-based flame retardants, Dec 602 was the most frequently detected chemical. Significant and positive correlations between the concentrations of PBDE congeners as well as between Dec 602 and Dec 603 were observed. Concentrations of PBDE congeners also showed significant and positive correlations in paired samples from family members (child-mother-father), while Dec 602 was the only hexachloronorbornene-based flame retardant whose concentrations correlated between family members, and only in mother-father paired samples. This is the largest study to date focusing on measuring and correlating HRFs in children and their parents living in the same household. The results convey important information on human exposure to measured HFRs, which can help researchers and regulators more clearly understand the influence of diet and the home environment.

Polychlorinated naphthalenes (PCNs) in seafood: Estimation of dietary intake in Korean population.

Polychlorinated naphthalenes (PCNs) were measured in 33 seafood species including fish, mollusks and crustaceans purchased from local markets in five Korean cities between 2012 and 2013. Five samples were collected from each species for the measurements. Thirty-seven PCN congeners from tetra-CN to octa-CN were measured. Octa-CN (octachloronaphthalene) was not detected in any of the samples. Tetra-CN and penta-CN were the predominant homologues of PCNs in seafood samples with PCN 51 and PCN 52/60 being the most abundant congeners in the samples. Total PCNs concentrations and their corresponding dioxin-like toxic equivalent (TEQ) values ranged from non-detection (ND) to 110pg/g on a wet weight (ww) basis and from ND to 0.14pg-TEQ/g ww, respectively. The estimated daily intake of total PCNs based on an absolute content and TEQ potency were estimated for the Koreans to be 570pg/day and 0.44pg-TEQ/day, respectively. However, the estimated TEQ value of PCNs intake from seafood, represented only a small fraction (3.0%) of the total TEQ intake from consumption of seafood in Korean population. This is the first report to exhibit the presence of PCNs in seafood samples collected from local markets in Korea and their intake by general population.

Levels of polybrominated diphenyl ethers in the Korean metropolitan population are declining: A trend from 2001 to 2013.

Polybrominated diphenyl ethers (PBDEs) have been banned or voluntarily withdrawn from commerce worldwide. Declining levels of PBDEs in humans have been reported elsewhere, but not in Korea. We monitored 7 individual PBDE congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) in 103 human serum samples collected in 2006. The arithmetic mean and median values for the sum of the 7 PBDEs (∑PBDEs) were 7.13 and 6.70 ng/g lipid, respectively. In addition, 6 pooled human serum samples collected in 2006, 2007, 2009, 2011, 2012, and 2013 were analyzed. A decrease in PBDE levels was observed, as reflected by the median value of ∑PBDEs from 5.98 in 2006 to 2.98 ng/g lipid in 2013 as well as in the pooled samples. The levels of individual congeners also decreased but at different declining rates. Based on these results and previously reported data, a definite decline in PBDE levels in the Korean metropolitan population could be observed from 2001 to 2013, providing the first evidence in Korea of the same decline observed elsewhere in the world. Environ Toxicol Chem 2018;37:2323-2330. © 2018 SETAC.

Dopamine transporter SPECT of a liver cirrhotic with atypical parkinsonism.

High level of exposure to manganese (Mn) can cause a clinically and pathophysiologically distinct syndrome from idiopathic Parkinson's disease (PD). We describe the clinical features and results of [123I]-fluoropropyl (FP)-CIT SPECT of a liver cirrhotic with atypical parkinsonism. The patient developed atypical parkinsonian features associated with elevated blood Mn from hepatic dysfunction. [123I]-FP-CIT brain SPECT images of dopamine transporter (DAT) demonstrated overall normal range of DAT uptake in the striatum although there were scattered small hypodense regions. The globus pallidum had increased signal on T1-weighted magnetic resonance imaging (MRI). All these findings are compatible with those of manganism, and are remarkably different from that in PD.

Human exposure to HBCD and TBBPA via indoor dust in Korea: Estimation of external exposure and body burden.

Human exposure to brominated flame retardants (BFRs) such as hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) mainly occurs through diet and dust ingestion. In this study, the BFR concentrations in 124 vacuum dust samples of six categories of indoor environments (homes, offices, kindergartens, cars, schools, and public indoor environments) and 32 surface dust samples were investigated. The median ΣHBCD concentrations ranged from 106.30ngg-1 in home dust to 496.13ngg-1 in office dust. The TBBPA concentrations in indoor dust (from 78.87 to 463.81ngg-1) were among the highest compared to other countries because of the high market demand for this flame retardant in Korea. The TBBPA concentrations in surface dust of living rooms were significantly higher (p<0.05) than sleeping rooms, due to the presence of more electrical equipment in living rooms. The estimated daily intakes (EDI) of ΣHBCD and TBBPA (dust+diet) for toddlers were 6.18ngkg-1bwd-1 and 2.54ngkg-1bwd-1, respectively. In general, the ΣHBCD estimated body burden of Korean adults showed good agreement with the reported ΣHBCD median concentrations in their sera. Since the developmental health effect of exposure to HBCD was categorized as "high hazard" by the US Environmental Protection Agency, the estimated high body burden of ΣHBCD in Korean toddlers (7.91ngg-1 lw) warns us of possible adverse effects on the development of essential systems in their bodies.

Surveillance of bacterial pathogens associated with acute diarrheal disease in the Republic of Korea during one year, 2003.

An epidemiological survey of human enterobacterial infections was conducted to determine the prevalence of enteropathogens in the Republic of Korea during one year, 2003. We tested for infectious diseases in 26,992 stool samples obtained from people who visited clinics located in six big cities and six rural provinces. From these samples, we isolated 1,291 cases of enteritis bacterial infection (4.8%). In the urban areas, 821 cases of bacterial infection (6.4%) were identified and, in the rural areas, 479 bacterial strains (3.3%) were isolated. Seasonal patterns were seen for diarrhea associated with S. aureus, E. coli and V. parahaemolyticus, while Salmonella and Shigella infections showed slight seasonal variation. We found that S. aureus and Salmonella were more frequently isolated from children and the elderly; however, the prevalence of E. coli, V. parahaemolyticus, and Shigella were similar in different age groups. Routine monitoring of these infections is considered a worthwhile means by which to elucidate their epidemiology and modes of transmission and ultimately to control them more effectively. Continuous laboratory-based surveillance for findings of enteritis bacterial infection should be emphasized in the prevention of these infections.

Occurrence of Dechlorane compounds and polybrominated diphenyl ethers (PBDEs) in the Korean general population.

Dechlorane compounds, including Dechlorane Plus (DP), mirex, and Dechlorane (Dec) 602, 603 and 604, were measured in 61 serum samples collected from a Korean urban area (Seoul) in 2013. Dechlorane Plus and Dec 602 were dominant in most samples, whereas Dec 604 was not detected in any samples. The median value of DP was 0.75 ng/g lipid, which was comparable with the levels observed in Europe and Canada, but lower than that observed in China. Statistically significant correlations among Dechlorane compounds were observed. The median anti-isomer fractional abundance (fanti) was 0.74, and a negative correlation between fanti and the DP concentration in serum samples was observed. Polybrominated diphenyl ethers (PBDEs) were also measured for comparison with Dechlorane compounds, and BDE-153 was found the most abundant congener with a median value of 1.43 ng/g lipid. A time trend of Dechlorane compounds was investigated in 7 pooled serum samples to cover the period from 2006 to 2013. A distinct trend of Dechlorane compounds was not observed, while PBDEs steadily decreased with time.

Estimated dietary intake and risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls from fish consumption in the Korean general population.

We analyzed 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (DL-PCBs) in samples from various fish species available at food markets in nine Korean cities. The estimated dietary intake of these chemicals was calculated from the raw concentrations of PCDD/Fs and DL-PCBs in each sample and from the food consumption of the Korean general population, and a comparison was made with the provisional tolerable monthly intake (PTMI). The average daily dietary exposure and the 95th percentile of intake of PCDD/Fs and DL-PCBs were 0.21 and 0.49 pg WHO05-toxic equivalents (TEQ) kg(-1) body weight d(-1) representing 5.27% and 12.26%, respectively, of the Korean tolerable daily intake (TDI). We applied the monthly fish consumption limits to the evaluation of improved risk assessment and concluded that unlimited consumption of most fish species does not contribute to the elevated cancer risk. This investigation was the first such large-scale study in Korea, and incorporated 37 species, including a species of whale, and 480 samples. The major aims of this study were to demonstrate the health risks associated with fish intake and to ensure food safety through total analysis of PCDD/Fs and DL-PCBs using gas chromatography/high-resolution mass spectrometry (GC-HRMS).

Analysis of the sacroiliac joint vacuum phenomenon in paediatric patients.

OBJECTIVE: To assess the incidence of the sacroiliac joint vacuum phenomenon (SIJ VP) in paediatric patients and the relationship between the presence of VP and clinical factors such as age, sex and body mass index (BMI). METHODS: We retrospectively reviewed clinical data and imaging findings of 60 patients who underwent abdominopelvic CT (AP CT) between January and June 2015. Patients were divided into VP group and non-VP group based on the presence/absence of VP, and the groups were compared. In addition, other degenerative changes in the SIJ were recorded. RESULTS: The SIJ VP was detected in 19 (31.6%) patients. There were no significant differences in sex distribution between VP and non-VP groups (p = 0.781). The age of the VP group was significantly higher than that of the non-VP group (p < 0.001). After adjusting the BMI for age, there was no significant association between high BMI and the presence of SIJ VP (p = 0.326). Other degenerative changes were not noted in any of the patients. CONCLUSION: The SIJ VP is not an uncommon finding in paediatric patients. The prevalence of SIJ VP in paediatric patients is similar to its prevalence in adults. The SIJ VP is related to patient age, but not to sex or BMI in children and young adolescents. Advances in knowledge: AP CT can provide information about the SIJ, if it is required to assess the SIJ in paediatric patients.