Evaluation of metal contamination in brackish area sediments South Korea, using receiver operation characteristic curve.

Brackish areas are where freshwater and seawater meet and possess high geographical and biological importance. However, no unified evaluation method exists for brackish sediments. Therefore, this study applies both the fresh water-sediment quality guidelines (F-SQGs) and the marine-sediment quality guidelines (M-SQGs) to evaluate metal contamination in brackish areas of Korea. The predicted reliability was examined using a receiver operation characteristic (ROC) curve. In the threshold effect level (TEL) evaluation of F-SQGs and M-SQGs, some metals (Cu, Zn, Hg, and Cd) showed significant differences according to guideline characteristics. The ROC curve showed that the predicted reliability of F-SQGs was 97.8 %, which was higher than M-SQGs (91.7 %). From the results of TEL evaluation and ROC curve prediction, F-SQGs are more suitable for the evaluation of brackish sediments in South Korea than M-SQGs.

Comparison of Indoor Air Quality in Summer and Winter According to Four-Way Cassette Fan Coil Unit Operation in a Four-Bed Ward.

This study targeted a four-bed ward with a ventilation system and a four-way cassette fan coil unit (4-way FCU) installed on the ceiling. The indoor air quality under summer and winter conditions was comparatively analyzed. The age of air was calculated by conducting tests and simulations under diverse conditions, assuming that the ventilation system and 4-way FCU were continuously operating. The use of an air cleaner and ward curtain was investigated for its impact on the air quality in the breathing zone of a patient lying on the bed, and effects of the airflow and discharge angle of the 4-way FCU were considered. Because the 4-way FCU was installed in the central part of the ceiling, where indoor air is sucked in and subsequently discharged in four directions, the age of air at each bed was found to vary depending on the airflow and discharge angle of the 4-way FCU. When the airflow and discharge angle of the 4-way FCU was fixed, the age of air at each bed appeared to be lower during winter heating than in summer cooling mode. The age of air was significantly lowered at each bed, depending on the use of the curtain and the air cleaner along with the ventilation system and 4-way FCU, and appropriate seasonal operating conditions were identified to maintain a lower age of air at each bed.

Investigation of the Optimal Operating Position of an Air Cleaner in Terms of Indoor Air Quality in a Four-Bed Hospital Ward.

The use of air cleaners indoors has increased with the increase in indoor activities driven by the COVID-19 outbreak. In this study, the indoor air quality was determined at the location of each patient's respirator in a four-bed hospital ward equipped with a ventilation system and curtains, by varying the position of one air cleaner. By operating the air cleaner alone without the ventilation system, it was confirmed that it is better to place the air cleaner close to the center of the ward, regardless of whether curtains are used. It was further identified that the farther away the air cleaner is from the center, the worse the age of air could be, compared to the case of operating it in the center. Moreover, the situation where the ventilation system and air cleaner were operated simultaneously in the hospital ward was considered. It was discovered that operating the air cleaner close to the ventilation inlets in the absence of curtains helps to improve the indoor air quality. Furthermore, it was found that the age of the air is generally low near the location where the air cleaner is operated in the presence of curtains. Selecting an optimal position for the air cleaner can improve the air quality at the location of each bed in a four-bed hospital ward.

End-of-life care practices in Korean nursing homes: A national survey.

BACKGROUND: Both globally and nationally, determinants of end-of-life care practices in nursing homes, such as laws and workforce, vary widely, resulting in a huge disparity in the quality of such practices. Despite the rapid growth in the number of nursing homes and increasing social attention being paid to end-of-life care in South Korea, little is known about these practices and how they differ because of nursing home-related regulations and nurse staffing. OBJECTIVES: To examine end-of-life care practices in nursing homes and compare them between nursing homes with 30 beds or more and those with fewer than 30 beds (the cut-point where nursing home-related regulations differ) and between nursing homes with and without registered nurses. DESIGN: A cross-sectional exploratory study using data from a national survey conducted by the National Health Insurance Service. SETTINGS: Nursing homes certified by the national long-term care insurance in South Korea. PARTICIPANTS: Nursing representatives from 836 nursing homes. METHODS: Measures of end-of-life care practices included the identification of residents' (or families') preferences for the place of death and a do-not-resuscitate order, the provision of end-of-life care on-site, and the presence of end-of-life care protocols. Descriptive statistics and logistic regression were used to compare end-of-life care practices by bed size and registered-nurse staffing. RESULTS: Of the 836 nursing homes, 85% and 84.1% identified the preference for the place of death and a do-not-resuscitate order mostly from surrogates, respectively. The most preferred places of death were nursing homes (53.3%) and hospitals (46.0%). Approximately, 72% responded that on-site end-of-life care protocols were present, and 50.8% reported providing end-of-life care on-site. Compared to nursing homes with 10-29 beds, those with 30 beds or more were more likely to identify the preference for a do-not-resuscitate order (OR 2.392, 95% CI 1.643-3.482); have in place end-of-life care protocols (OR 1.829, 95% CI 1.341-2.496); and provide end-of-life care on-site (OR 1.556, 95% CI 1.169-2.072). Compared to nursing homes without registered nurses, those with registered nurses were also more likely to identify the preference for a do-not-resuscitate order (OR 1.717, 95% CI 1.142-2.583) and provide end-of-life care on-site (OR 1.663, 95% CI 1.254-2.206). CONCLUSIONS: The findings indicate a huge disparity in end-of-life care practices in nursing homes across South Korea by bed size-based nursing-home regulations and registered-nurse staffing. Law/regulation- and policy-level changes are needed to promote robust end-of-life care in nursing homes. STUDY REGISTRATION: Not registered.

Socioeconomic Costs of Dementia Based on Utilization of Health Care and Long-Term-Care Services: A Retrospective Cohort Study.

This study examined the socioeconomic costs of dementia based on the utilization of healthcare and long-term care services in South Korea. Using 2016 data from two national insurance databases and a survey study, persons with dementia were categorized into six groups based on healthcare and long-term care services used: long-term care insurance users with home- and community-based services (n = 93,346), nursing home services (n = 69,895), and combined services (n = 16,068); and long-term care insurance non-users cared for by family at home (n = 192,713), living alone (n = 19,526), and admitted to long-term-care hospitals (n = 65,976). Their direct and indirect costs were estimated. The total socioeconomic cost of dementia was an estimated US$10.9 billion for 457,524 participants in 2016 (US$23,877 per person). Among the six groups, the annual per-person socioeconomic cost of dementia was lowest for long-term care insurance users who received home- and community-based services (US$21,391). It was highest for long-term care insurance non-users admitted to long-term care hospitals (US$26,978). Effective strategies are necessary to promote long-term care insurance with home- and community-based services to enable persons with dementia to remain in their communities as long as possible while receiving cost-efficient, quality care.

Effects of polluted and non-polluted suspended sediments on the oxygen consumption rate of olive flounder, Paralichthys olivaceus.

The potential ecological impacts of elevated suspended sediments (SS) in coastal areas due to human activities remain unclear. In particular, physiological response of benthic fish to SS exposure in polluted environment has not been documented. We determined sub-lethal toxicity of polluted and non-polluted SS to olive flounder. Test organism was exposed to varying concentrations of SS (0-4000 mg L-1) and real-time oxygen consumption rate (OCR) was measured for 12 h. The early-juvenile was sensitive to SS, particularly at >500 mg L-1, but late-juvenile was tolerant up to 4000 mg SS L-1. Metal polluted SS (HQmetal > 1) increased OCR in general, particularly at >1000 SS mg L-1. Combined effect of copper and SS exposure on fish was either synergistic or antagonistic. Overall, potential adverse effect of polluted SS on fish greatly varied at different life stage and/or by metal pollution gradients.

Newly Identified AhR-Active Compounds in the Sediments of an Industrial Area Using Effect-Directed Analysis.

Effect-directed analysis was used to identify previously unidentified aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area of Ulsan Bay, Korea. The specific objectives were to (i) investigate potent fractions of sediment extracts using the H4IIE-luc bioassay, (ii) determine the concentrations of known AhR agonists (polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs)), (iii) identify previously unreported AhR agonists in fractions by use of GC-QTOFMS, and (iv) evaluate contributions of individual compounds to overall AhR-mediated potencies, found primarily in fractions containing aromatics with log Kow 5-8. Greater concentrations of PAHs and SOs were also found in those fractions. On the basis of GC-QTOFMS and GC-MSD analyses, 16 candidates for AhR agonists were identified in extracts of sediments. Of these, seven compounds, including 1-methylchrysene, benzo[j]fluoranthene, 3-methylchrysene, 5-methylbenz[a]anthracene, 11H-benzo[b]fluorene, benzo[b]naphtho[2,3-d]furan, and benzo[b]naphtho[2,1-d]thiophene, exhibited significant AhR activity. Relative potency values of newly identified AhR agonists were found to be greater than or comparable to that of benzo[a]pyrene (BaP). The potency balance analysis showed that newly identified AhR agonists explained 0.07-16% of bioassay-derived BaP-EQs. These chemicals were widely distributed in industrial sediments; thus, it is of immediate importance to conduct studies on sources and potential effects of those chemicals.

Evaluation of residual toxicity of hypochlorite-treated water using bioluminescent microbes and microalgae: Implications for ballast water management.

Total residual oxidants (TRO) in treated ballast water can produce various disinfection by-products (DBPs) depending on local conditions, such as salinity and organic matter content in water. Because TRO and DBPs are known to be harmful to aquatic organisms and humans, ecotoxicity tests have been proposed for screening the residual toxicity before discharging treated ballast water. In the present study, we aimed to address the decay rates and toxicity changes of TRO under various conditions in salinity, initial TRO concentrations, and residence time of TRO. In addition, the toxicological sensitivities of bioluminescent bacteria Vibrio fischeri and a commonly-used microalgae Skeletonema costatum relative to the residual toxicity of TRO and six selected DBPs were determined. Decay rate of TRO concentration increased as a function of salinity and was affected by the initial concentrations of TRO. Unexpectedly, significant bioluminescence inhibition was observed for hypochlorite-treated water at < 0.1 mg L-1 TRO (expressed as Cl2), which is a lower concentration than the maximum allowable discharge concentration (MADC) to marine waters established by the International Maritime Organization (IMO). The ecotoxicological thresholds of no observed effective concentration and median effect concentration for all tested DBPs were about 3-10 times lower for V. fischeri than for S. costatum. The results indicate that bioluminescent microbes possess an ecologically-relevant sensitivity to both TRO and DBPs in ballast water. In general, bioassay using V. fischeri was potentially more effective than microalgae for screening the total toxicity of TRO and DBPs in treated ballast water, especially given that ballast water usually contains a highly variable and complex mixture of toxicants.

Potential ecotoxicological effects of elevated bicarbonate ion concentrations on marine organisms.

Recently, a novel method for carbon capture and storage has been proposed, which converts gaseous CO2 into aqueous bicarbonate ions (HCO3-), allowing it to be deposited into the ocean. This alkalinization method could be used to dispose large amounts of CO2 without acidifying seawater pH, but there is no information on the potential adverse effects of consequently elevated HCO3- concentrations on marine organisms. In this study, we evaluated the ecotoxicological effects of elevated concentrations of dissolved inorganic carbon (DIC) (max 193 mM) on 10 marine organisms. We found species-specific ecotoxicological effects of elevated DIC on marine organisms, with EC50-DIC (causing 50% inhibition) of 11-85 mM. The tentative criteria for protecting 80% of individuals of marine organisms are suggested to be pH 7.8 and 11 mM DIC, based on acidification data previously documented and alkalinization data newly obtained from this study. Overall, the results of this study are useful for providing baseline information on ecotoxicological effects of elevated DIC on marine organisms. More complementary studies are needed on the alkalinization method to determine DIC effects on seawater chemistry and marine organisms.

Rapid preparation of a noncultured skin cell suspension that promotes wound healing.

Autologous skin cell suspensions have been used for wound healing in patients with burns and against normal pigmentation in vitiligo. To separate cells and the extracellular matrix from skin tissue, most researchers use enzymatic digestion. Therefore, this process is difficult to perform during a routine surgical procedure. We aimed to prepare a suspension of noncultured autologous skin cells (NCSCs) using a tissue homogenizer as a new method instead of harsh biochemical reagents. The potential clinical applicability of NCSCs was analyzed using a nude-rat model of burn healing. After optimization of the homogenizer settings, cell viability ranged from 52 to 89%. Scanning electron microscopy showed evidence of keratinocyte-like cell morphology, and several growth factors, including epidermal growth factor and basic fibroblast growth factor, were present in the NCSCs. The rat model revealed that NCSCs accelerated skin regeneration. NCSCs could be generated using a tissue homogenizer for enhancement of wound healing in vivo. In the NCSC group of wounds, on day 7 of epithelialization, granulation was observed, whereas on day 14, there was a significant increase in skin adnexa regeneration as compared to the control group (PBS treatment; p < 0.05). This study suggests that the proposed process is rapid and does not require the use of biochemical agents. Thus, we recommend a combination of surgical treatment with the new therapy for a burn as an effective method.

Protective effects of polysaccharides from Psidium guajava leaves against oxidative stresses.

The aim of this study was to analyze antioxidant properties of a polysaccharide isolated from Psidium guajava leaves (PS-PGL) in vitro including its radical scavenging activities and protective effects against damage to cells as well as in vivo in zebrafish. The water extract of P. guajava leaves (WE-PGL) and PS-PGL showed strong radical scavenging effects in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and alkyl radical. Compared to WE-PGL, PS-PGL enhanced all scavenging activities and in particular strongly scavenged the hydroxyl radical (50% inhibitory concentration [IC50], 0.02mg/mL). In addition, PS-PGL exerted a protective effect against hydrogen peroxide-induced oxidative stress and against toxicity to Vero cells. Furthermore, in vivo experiments using zebrafish embryos indicated that treatment with hydrogen peroxide decreased the survival rate and heart-beating rate of zebrafish embryos, whereas these problems were reduced by PS-PGL treatment. Moreover, PS-PGL inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production, lipid peroxidation, and cell death. Taken together, these results suggest that PS-PGL may be useful as a beneficial antioxidant material in the food and cosmetic industries.

Arsenic speciation in water, suspended particles, and coastal organisms from the Taehwa River Estuary of South Korea.

Water, suspended particulate matter (SPM), and biota samples were collected from the Taehwa River Estuary to determine the distributions, partitioning, and bioaccumulation of arsenicals. Six forms of As were quantitated by the use of HPLC-ICP/MS. As was found mainly near urban and industrial areas, and inorganic As(V) was the predominant As form in both water and SPM. Particulate arsenicals were found at the greatest concentrations in coarse particles (>180µm), followed by medium (30-180µm) and fine (0.45-30µm) particles, in freshwater. Arsenical concentrations were similar across the three particle fractions in saltwater. Field-based distribution coefficient (Kd) values for As depended strongly on SPM, with a less robust dependence on salinity. Concentrations of As were greater in macroalgae than in marine animals, such as fishes, bivalves, crabs, shrimps, and gastropods. Overall, the results of the present study provide useful information on the behaviors and fate of arsenicals in an estuarine environment.

Comparison between cryopreserved and glycerol-preserved allografts in a partial-thickness porcine wound model.

Human skin allografts are one of the best temporary biological coverings for severely burned patients. Cryopreserved (CPA) and glycerol-preserved (GPA) allografts are the most widely used types. This study compared the allograft efficiency of both preservation methods under the same conditions. To simulate actual clinical conditions, we used a porcine wound model. In addition, we evaluated the macroscopic and microscopic scoring of graft performance for each method. Porcine cadaver skin 1 mm thick was obtained from one pig. Cryopreserved skin cell viability was 20.8 %, glycerol-preserved skin was 9.08 %, and fresh skin was 58.6 %. We made ten partial-thickness wounds each in two pigs. The take rates on day 2 were 96.23 and 82.65 % in the GPA and CPA group (both n = 9), respectively. After 1 week, the take rates of both groups were nearly equal. The removal rate at week 5 was 98.87 and 94.41 % in the GPA and CPA group, respectively. On microscopic findings at week 2, inflammation was greater in the CPA group. Other findings such as fibroblast hyperplasia and neovascularization were not significantly different between both groups. At week 5, the score of collagen fiber synthesis was 2.67 ± 0.47 and 2.33 ± 0.47 in the GPA and CPA group, respectively. The epidermal-dermal junction was 2.22 ± 0.79 and 2.00 ± 0.47 in the GPA and CPA group, respectively. These findings suggest that wound healing takes longer in the CPA group. The preservation method of allografts is not a absolute factor in the wound healing process in this wound model.

Three Different Methods in Deformity Correction of Degenerative Flat Back: A Single Surgeon's Experience with 64 Consecutive Cases.

STUDY DESIGN: Retrospective study. PURPOSE: To evaluate the radiological and clinical results of three different methods in the deformity correction of a degenerative flat back. OVERVIEW OF LITERATURE: There are no comparative studies about different procedures in the treatment of degenerative flat back. METHODS: Sixty-four patients who consecutively underwent corrective surgery for degenerative flat back were reviewed. The operations were performed by three different methods: posterior-only (group P, n=20), one-stage anterior-posterior (group AP, n=12), and two-stage anterior-posterior with iliac screw fixation (group AP-I, n=32). Medical and surgical complications were examined and radiological and clinical results were compared. RESULTS: The majority of medical and surgical complications were found in group AP (5/12) and group P (7/20). The sagittal vertical axes were within normal range immediately postoperatively in all groups, but only group AP-I showed normal sagittal alignment at the final follow-up. Postoperative lumbar lordosis was also significantly higher in group AP-I than in group P or group AP and the finding did not change through the last follow-up. The Oswestry disability index was significantly lower in groups AP and AP-I than in group P at the final follow-up. Meanwhile, the operating time was the longest in group AP-I, and total amount of blood loss was larger in group AP-I and group AP than in group P. CONCLUSIONS: Anterior-posterior correction showed better clinical results than posterior-only correction. Two-staged anterior-posterior correction with iliac screw fixation showed better radiological results than posterior-only or one-staged anterior-posterior correction. Two-staged anterior-posterior correction with iliac screw fixation also showed a lower complication rate than one-staged anterior-posterior correction.

Comparison of Gene Expression Profiles between Keratinocytes, Melanocytes and Fibroblasts.

BACKGROUND: The skin has many important functions such as protection, preservation, temperature regulation, and vitamin D synthesis. It is composed of a variety of cell types including keratinocytes, melanocytes and fibroblasts. OBJECTIVE: We attempted to compare the gene expression profiles between keratinocytes, melanocytes and fibroblast, using cDNA microarray. METHODS: Keratinocytes, melanocytes and fibroblasts were primary cultured from five foreskin specimens. Total RNAs were extracted and pooled to reduce the individual variations, and then used for cDNA microarray. RESULTS: Total 12,028 genes were selected as the reliable genes whose expression was detected in at least one of the three cell types. By comparing the relative expression levels with cutoff limitation as a fourfold change, we obtained 126 fibroblast-specific, 179 keratinocyte-specific and 173 melanocyte-specific genes, many of which are known to be characteristically expressed in each cell type. In addition, we identified many genes whose skin-specific functions have not yet been determined. CONCLUSION: Our data provide important information on which to base further investigation into the specification of skin cell types.

Expression profiling of calcium induced genes in cultured human keratinocytes.

Terminal differentiation of skin keratinocytes is a vertically directed multi-step process that is tightly controlled by the sequential expression of a variety of genes. To examine the gene expression profile in calcium-induced keratinocyte differentiation, we constructed a normalized cDNA library using mRNA isolated from these calcium-treated keratinocytes. After sequencing about 10,000 clones, we were able to obtain 4,104 independent genes. They consisted of 3,699 annotated genes and 405 expressed sequence tags (ESTs). Some were the genes involved in constituting epidermal structures and others were unknown genes that are probably associated with keratinocytes. In particular, we were able to identify genes located at the chromosome 1q21, the locus for the epidermal differentiation complex, and 19q13.1, another probable locus for epidermal differentiation-related gene clusters. One EST located at the chromosome 19q13.1 showed increased expression by calcium treatment, suggesting a novel candidate gene relevant to keratinocyte differentiation. These results demonstrate the complexity of the transcriptional profile of keratinocytes, providing important clues on which to base further investigations of the molecular events underlying keratinocyte differentiation.

Prediction and evaluation of protein-protein interaction in keratinocyte differentiation.

Terminal differentiation of skin keratinocytes is a vertically directed multi-step process that is tightly controlled by the sequential expression of a variety of genes. We previously investigated the gene expression profile and found that many of differentiation-related genes expressed in a temporally regulated manner. In this study, we attempted to find the hub-molecules and their intracellular signaling networks during keratinocyte differentiation using in silico analysis of data obtained from previous studies. We used protein-protein interaction prediction software called PSIMAP, and drew a hypothetical signaling network. We chose one candidate hub-molecule SHC1 that were predicted to link EGFR and MAPK signal, and then evaluated the protein-protein interactions experimentally. As predicted, SHC1 bound to the MEK1 in an EGF-regulated manner. Furthermore, SHC1 bound to the MEK1 and p38 MAPK in a keratinocyte differentiation dependent manner. These results demonstrate that in silico protein-protein interaction prediction system can be used to efficiently and cost-effectively select the experimental candidates.

Comparison of Selenium bioaccumulation in the clams Corbicula fluminea and Potamocorbula amurensis: a bioenergetic modeling approach.

Selenium uptake from food (assimilation efficiency) and dissolved phase (influx rate) as well as loss kinetics (efflux rate) were compared between two bivalves, Corbicula fluminea and Potamocorbula amurensis. The effects of salinity and temperature on these kinetic parameters for both clam species also were evaluated. The Asiatic clam, C. fluminea, more efficiently assimilated Se associated with algae (66-87%) than Se associated with oxic sediments (20-37%). However, no consistent difference was found between Se assimilation efficiencies from both food types (19-60%) for P. amurensis. The temperature and salinity had a minor influence on the Se assimilation from ingested food. However, the effects of temperature and salinity were more evident in the uptake from dissolved sources. The influx rate of Se(IV) increased by threefold with the increase of temperature from 5 to 21 degrees C for C. fluminea. The increase of salinity from 4 to 20 psu decreased the uptake rate constant (ku) of Se in P. amurensis from 0.011 to 0.005 L/g/h, whereas salinity change (0-8 psu) had a negligible effect on the Se influx rate of C. fluminea. The Se influx rate of P. amurensis decreased by half with the 3.5-fold increase in tissue dry weight. The rate constant of loss was greater for P. amurensis (0.029/d at 8 psu) than for C. fluminea (0.014/d at 0 psu and 0.01/d at 8 psu). A bioenergetic model suggests that dietary uptake is the dominant pathway for Se bioaccumulation in the two clams in San Francisco Bay and that interspecies differences in Se bioaccumulation can be explained by differences in food ingestion rates.

Molecular cloning and expression of human keratinocyte proline-rich protein (hKPRP), an epidermal marker isolated from calcium-induced differentiating keratinocytes.

We isolated a human gene encoding keratinocyte proline-rich protein (hKPRP). hKPRP gene is located in the region of epidermal differentiation complex on chromosome 1q21, and its approximately 2.5 kb mRNA encodes 579 amino acid protein with high proline content (18%). The mRNA level of hKPRP was markedly increased at both 7 and 14 d after treatment with 1.2 mM calcium in cultured normal human epidermal keratinocytes. In situ hybridization demonstrated that hKPRP was expressed in upper granular layer of normal epidermis with characteristic intermittent pattern. In psoriatic lesion, hKPRP expression was increased as compared with normal skin and showed continuous pattern. Immunohistochemical analysis also confirmed the expression of hKPRP at the protein level. Western blot analysis showed that hKPRP protein of approximately 70 kDa size was significantly increased by calcium in a time-dependent manner. In mouse tissue blot assays, the expression of KPRP was detected in stomach and skin tissues, and began at 17.5 embryonic days. Additionally, hKPRP expression was detected in the periderm of human fetal skin from 16 wk estimated gestational age. Together, these results suggest that hKPRP is an epidermal marker expressed in stratified squamous epithelia and has a potential role in keratinocytes differentiation.