• Korean journal of applied entomology
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• v.52 no.1
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• pp.35-43
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• 2013

All tested Korean populations of the diamondback moth, Plutella xylostella, are known to be resistant especially against pyrethroid insecticides by mutation in its molecular target, para-sodium channel. Moreover, P. xylostella is able to develop resistance against most commercial insecticides. This study was performed to develop an efficient control technique against P. xylostella by a combined treatment of an endoparasitoid wasp, Cotesia plutellae, and a microbial insecticide, Bacillus thuringiensis. To investigate any parasitism preference of C. plutellae against susceptible and resistant P. xylostella, five different populations of P. xylostella were compared in insecticide susceptibilities and parasitism by C. plutellae. These five P. xylostella populations showed a significant variation against three commercial insecticides including pyrethroid, organophosphate, neonicotinoid, and insect growth regulator. However, there were no significant differences among five P. xylostella populations in their parasitic rates by C. plutellae. Moreover, parasitized larvae of P. xylostella showed significantly higher susceptibility to B. thuringiensis. As an immunosuppressive agent, viral ankyrin genes (vankyrins) encoded in C. plutellae were transiently expressed in nonparasitized larvae. Expression of vankyrins significantly enhanced the efficacy of B. thuringiensis against the third instar larvae of P. xylostella. Thus an immunosuppression induced by C. plutellae enhanced the insecticidal efficacy of B. thuringiensis. These results suggest that a combined treatment of C. plutellae and B. thuringiensis may effectively control the insecticide-resistant populations of P. xylostella.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.167-173
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• 2021

Sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an insect pest with sucking mouth part and globally attacks diverse crops and vegetables. Since first reported in 1998, it is now widely spread in many regions in Korea. Due to insecticide resistance, it is necessary for optimal control of the whiteflies to select effective insecticides with precise insecticide resistance monitoring. In this study, B. tabaci individuals were collected from 12 regions in 7 provinces of Korea from June to September in 2020. Using these field populations, insecticide resistance levels were monitored using a residual contact bioassay along with molecular markers. Bioassay results revealed that B. tabaci possessed high levels of resistance to five insecticides exhibiting different modes of action: dinotefuran, spinosad, emamectin benzoate, chlorfenapyr, and bifenthrin. In addition, quantitative sequencing in target sites of organophosphate and pyrethroid insecticides revealed that point mutations reached to saturated or near-saturated levels across the country. This suggests that insecticide resistance management is required for effective control of B. tabaci populations in Korea.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.284-288
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• 2010

A series of experiments was carried out for selecting insecticides and determining proper spraying time to control pea weevil (Bruchus pisorum Linnaeus) in Jeonnam area. In the field trial two times spray with diazinon, carbaryl, imidacloprid, spinosad, etofenprox, clorpyrifos-methyl showed good control effect and threetimes spray showed the better control effect. The second spray (spraying on 10th of May) took the major role of insecticide effectiveness expression for controlling pea weevil. Further trial for selecting insecticides among organophosphates to control pea weevil in lab was conducted and every organophosphate insecticide tested was very effective to pea weevil even at the concentration of one forth of its recommending concentration.

• Journal of The Korean Society of Clinical Toxicology
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• v.5 no.1
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• pp.8-14
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• 2007

Purpose: Organophosphorus insecticides tend to be regarded as a homogeneous single entity. We aimed to determine whether organophosphate poisoning differs by subgroups in clinical features and severity. Methods: We retrospectively reviewed medical records of all patients with acute organophophorus poisoning from January 1998 to December 2006. We investigated clinical features, Glasgow coma scale (GCS), laboratory findings, QTc intervals, management, and outcomes. Results: A total of 109 patients were included. The dimethoxy group experienced significantly longer times than the diethoxy group for ventilation duration (0.6 day vs. 0.2 day, p=0.006), ICU duration (2.0 day vs. 0.8 day, p=0.037), and total admission duration (2.8 day vs. 0.9 day, p=0.008), except in cases of dichlorvos poisoning. Also, the GCS of the dimethoxy group (except with dichlorvos) was significantly lower than for the diethoxy group (dimethoxy, $11.2{\pm}5.2$ vs. diethoxy, $13.8{\pm}2.4$, p= 0.021). QTc intervals for the dimethoxy group (except with dichlorvos) tended to be somewhat greater than for the diethoxy group (dimethoxy, $452.9{\pm}16.1\;msec$ vs. diethoxy, $429.6{\pm}40.9\;msec$). There were 65 patients with dichlorvos ingestion, and 2 of these patients (3%) died. Conclusion: When compared to the diethoxy group, the dimethoxy group of organophosphates (with the exception of dichlorvos) were associated with poorer prognostic value for indicators such as GCS, QTc interval, requirement for intubation, ICU duration, and total admission duration. Within the dimethoxy group, patients with dichlorvos poisoning had relatively better prognoses than for the other dimethoxy group organophosphates studied.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.941-952
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• 2023

The metabolites of agrichemicals, such as organophosphorus pesticides, are known to be more hazardous than their parent pesticides. 3,5,6-trichloro-2-pyridinol (TCP) is a major degradation product of chlorpyrifos, one of the organophosphate insecticides widely used in agriculture. In vivo or in vitro exposure to chlorpyrifos has been known to interfere with male reproductive functions, leading to reduced fertility in mammals. Therefore, this study was performed to examine the changes in the fertilization competence of boar spermatozoa exposed to TCP. Sperm samples were subjected to varying concentrations of TCP (10, 50, 100, 200 µM) and different periods of incubation. Sperm motility, motion kinematics, viability, acrosome integrity, intracellular reactive oxygen species (ROS) production, and gene expression levels (ODf2, ZPBP2, AKAP3 and AKAP4) were evaluated after exposure of the sperm to TCP. A significant dose-dependent reduction in motility was observed in sperm samples incubated with TCP compared to the controls after both incubation periods. Sperm viability was significantly decreased in samples incubated with 50, 100, and 200 µM TCP in both incubation periods. A significantly lower percentage of normal acrosomes and gene expression levels were observed in sperm samples exposed to 50, 100, and 200 µM TCP after both incubation periods, compared to the controls. There was a significant increase in the ROS production in spermatozoa incubated with 100 - 200 µM TCP after both incubation periods. Consequently, the direct exposure of boar spermatozoa to TCP interferes with sperm functions and leads to decreased fertilization. In order to identify and address the various causes of reproductive decline, the impact of chemical metabolites needs to be discussed in depth.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.353-360
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• 2003

For the simple rapid bioassay of organophosphorus and carbamate pesticide residues, a mass-production system of acetycholinesterase (AChE, EC 3.1.1.7, MAChE) using baculovirus and insect cell culture was constructed. The cDNA for AChE was synthesized from Drosophila melanogaster in Halla Mountain, the lipid anchor tail was removed by PCR and was used for the site-directed mutagenesis of three amino acid residues (E107Y, F368L, L408F). The mutated cDNA was inserted into the baculovirus vector and expressed in insect cells. Maximum cell growth and enzyme activity were reached when the cells $(2{\times}10^6\;cell/ml)$ were infected four times at four-day-intervals. His-tag containing MAChE was purified using Ni-NTA column and used for characterization. The activity was maintained under various pHs (3-10) and temperatures $(20-50^{\circ}C)$ under experimental conditions. As an extraction solution for pesticides, methanol is more effective than ethanol. Against major organophosphate and carbamate pesticides, the MAChE showed better sensitivity than AChE and AChE from housefly (Taiwan).

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.134-140
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• 2008

The data on pesticide poisoning death toll during 2000-2005 was obtained from Korean National Statistical Office and analysed to find out any precautionary measures against pesticide poisonings. Pesticide poisoning death toll showed slightly increasing trend with year up to about 3500 in 2005. Most of the pesticide poisoning death cases were intentional self-poisoning accounting for more than 80% of total pesticide poisoning death. The pesticide most often implicated in poisoning death were paraquat dichloride, a non-selective herbicide and organophosphate/carbamate insecticides. The regional distribution of pesticide poisoning death showed urban 21.6% and rural area 78.4%. As for the occupation of the dead, agricultural, forestry and fishery workers accounted for 27.4% and non-agricultural workers was 72.6% of pesticide poisoning death. Therefore, government need to take some precautionary measures to reduce the number of pesticide poisoning cases. It is strongly recommended that pesticide regulatory authorities encourage and train the agricultural workers to use safe storage boxes and enforce strict regulation for the prevention for the prevention of highly toxic pesticides sales to non-agricultural workers.

• Journal of The Korean Society of Clinical Toxicology
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• v.17 no.1
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• pp.21-27
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• 2019

Purpose: Mortality rate in the health services research field is frequently considered as a proxy for measuring healthcare quality. We compared the mortality rate and hospitalization levels among patients with poisoning. Methods: A population-based study of hospital size and level based on the Korean health insurance and assessment service was conducted to identify the impact of hospital level on patient mortality. Results: We analyzed a total of 16,416 patients, of which 7,607 were from tertiary hospitals, 8,490 were from general hospitals, and 319 were from hospitals. The highest mortality rate of diagnosis regarding poisoning was T60.31 (other herbicides and fungicides, 16%), followed by T60.0 (organophosphate and carbamate insecticides, 12.7%). There was no statistical difference in mortality among hospital levels for gender. Among age groups, tertiary hospitals had lower mortality than general hospitals and hospitals for patients aged more than 70 years (11.9% mortality at tertiary vs 14.2% at general and 23% at hospital; p=0.003, adjusted z score=-6.9), general hospitals had lower mortality than tertiary hospitals and hospitals for patients aged 18 to 29 (0.6% at general vs 2.4% at tertiary and 3.7% at hospital; p=0.01, adjusted z score=-4.3), and hospitals had lower mortality than tertiary hospitals and general hospitals for patients between 50 and 59 years of age (0% at hospital vs 6.4% at general and 8.3% at tertiary; p=0.004). Conclusion: Overall, there was no significant difference between mortality and hospital level among poisoned patients. However, to establish an efficient treatment system for patients with poisoning, further studies will be needed to identify the role of each facility according to hospital level.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.194-215
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• 2021

Termites are important decomposers in the ecosystem. They are also economically significant structural pests. In this study, we reviewed the developments of termite control and recent research on termite management to provide information on the prevention and control of termites. In Korea, most of the damage to wooden historical buildings is caused by subterranean termites. Reticulitermes speratus kyushuensis is the main species, which is widely found throughout the country. In the early 1900s, inorganic insecticides, such as arsenic dust, were used for termite control. After the synthesis of chlorinated hydrocarbon pesticide in the 1940s, it was widely utilized and demonstrated high termite control efficacy. However, chlorinated hydrocarbon insecticides were later banned, disappearing from markets after reports emerged concerning environmental contamination and toxicity to humans. Therefore, the termite control industry sought a new termiticide; hence many pesticides were utilized for termite control. Organophosphate (1960s), carbamate (1970s), pyrethroid, and insect growth inhibitor (1980s) were newly synthesized and adopted. In the 1990s, the first commercial baits using chitin synthesis inhibitors (CSI) were developed, providing a means to eliminate an entire colony of subterranean termites around a structure. Many studies have been carried out on soil termiticides (liquid termiticides) and CSI baits to increase their efficacy, and different baits such as aboveground bait stations, fluid bait, and high-durability bait were also developed in the 2000s. In addition, the paradigm of termite control has shifted from localized treatments using soil termiticides to area-wide pest management using CSI baits to create termite-free zones and protect buildings over time. Termite infestations in wooden historical buildings in Korea have been reported since 1980, and considerable attention was drawn in the 1990s when several UNESCO world heritages such as the Jongmyo Shrine and the Janggyeong Panjeon Depositories of Haeinsa Temple were infested by subterranean termites. Since then, a survey of termite infestation in wooden architectural heritage has been conducted, and the National Research Institute of Cultural Heritage and Heritage Care Program regularly monitors those properties. Finally, we suggest termite management using primarily CSI baits, selective application of various soil treatments applied to the object, foundation soil treatment, research and development of durable termite baits, application of area-wide programs for wooden-building complexes, application of integrated termite management (ITM), and regular education for owners and managers to prevent and reduce termite damage.

• Tuberculosis and Respiratory Diseases
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• v.59 no.4
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• pp.380-388
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• 2005

Background : Acute drug intoxication has recently become an important issue in the social and clinical areas. There are various complications associated with acute drug intoxication such as pneumonia, but the process is was not fully understood. The aim of this study was to analyze our cases of pneumonia associated with acute drug intoxication and to determine the associated risk factors. Methods : Forty four cases out of 237 patients, who were acute drug intoxicated from May 2000 to Feb. 2005, were diagnosed with pneumonia at the Konyang University hospital. These cases were analyzed by a retrospective review of their medical records. Results : The incidence of pneumonia in acute drug intoxication was 18.6%. There was no gender difference in terms of the incidence, but the age group with the highest incidence was in the $5^{th}$ decade (22.5%) followed by the $7^{th}$ decade (17.9%). Most common drug of associated with pneumonia was organophosphate insecticides, and the others were herbicides. Suicidal attempts were the most common motive of intoxication. The incidence of pneumonia was increased in old age (${\beta}=0.128$, p<0.05). A drowsy or comatous mental status was an independent risk factors of pneumonia (${\beta}=-0.209$, p=0.006). A longer hospital duration was also a risk factor for pneumonia (${\beta}=0.361$, p<0.001). The intubated state, intensive care unit care and longer duration of admission correlated with the course of pneumonia in acute drug intoxicated patients (p<0.05). The culture study revealed MRSA to be most common pathogen. Conclusion : The incidence of pneumonia associated with acute drug intoxication was higher in the older aged patients, those with a decreased initial mental status and a longer hospital duration. The number of days in the intensive care unit and intubation were associated prognostic factors for pneumonia in acute drug intoxication patients.