Publications by authors named "Aeran Kim"

20 Publications

  • Page 1 of 1

Development of a compact X-band linear accelerator system mounted on an O-arm rotating gantry for radiation therapy.

Rev Sci Instrum 2021 Feb;92(2):024103

Electro-Medical Device Research Center, Korea Electrotechnology Research Institute, Ansan 15588, South Korea.

A compact X-band linear accelerator (LINAC) system equipped with a small and lightweight magnetron was constructed to develop a high-precision image-guided radiotherapy system. The developed LINAC system was installed in an O-ring gantry where cone-beam computed tomography (CBCT) was embedded. When the O-arm gantry is rotated, an x-ray beam is stably generated, which resulted from the stable transmission of radio frequency power into the X-band LINAC system. Quality assurance (QA) tests, including mechanical and dosimetry checks, were carried out to ensure safety and operation performance according to the American Association of Physicists in Medicine's TG-51, 142, an international standard protocol established by accredited institutions. In addition, delivery QA of the radiotherapy planning system was conducted to verify intensity-modulated radiotherapy techniques. Therefore, it was demonstrated that the developed X-band LINAC system mounted on the O-arm gantry proved to be valid and reliable for potential use in CBCT image-guided radiation therapy.
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http://dx.doi.org/10.1063/5.0030271DOI Listing
February 2021

Verification of lithium formate monohydrate in 3D-printed container for electron paramagnetic resonance dosimetry in radiotherapy.

Australas Phys Eng Sci Med 2019 Sep 13;42(3):811-818. Epub 2019 Aug 13.

Advanced Institute for Radiation Fusion Medical Technology, College of Medicine, The Catholic University of Korea, Annex B1 222 Banpo Road (Catholic University Seoul St. Mary's Hospital), Seocho-gu, Seoul, Korea.

The nondestructive dosimetry achieved with electron paramagnetic resonance (EPR) dosimetry facilitates repetitive recording by the same dosimeter to increase the reliability of data. In precedent studies, solid paraffin was needed as a binder material to make the lithium formate monohydrate (LFM) EPR dosimeter stable and nonfragile; however, its use complicates dosimetry. This study proposes a newly designed pure LFM EPR dosimeter created by inserting LFM into a 3D-printed container. Dosimetric characteristics of the LFM EPR dosimeter and container, such as reproducibility, linearity, energy dependence, and angular dependence, were evaluated and verified through a radiation therapy planning system (RTPS). The LFM EPR dosimeters were irradiated using a clinical linear accelerator. The EPR spectra of the dosimeters were acquired using a Bruker EMX EPR spectrometer. Through this study, it was confirmed that there is no tendency in the EPR response of the container based on irradiation dose or radiation energy. The results show that the LFM EPR dosimeters have a highly sensitive dose response with good linearity. The energy dependence across each photon and electron energy range seems to be negligible. Based on these results, LFM powder in a 3D-printed container is a suitable option for dosimetry of radiotherapy. Furthermore, the LFM EPR dosimeter has considerable potential for in vivo dosimetry and small-field dosimetry via additional experiments, owing to its small effective volume and highly sensitive dose response compared with a conventional dosimeter.
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http://dx.doi.org/10.1007/s13246-019-00786-xDOI Listing
September 2019

MERS transmission and risk factors: a systematic review.

BMC Public Health 2018 05 2;18(1):574. Epub 2018 May 2.

Herbal Medicine Research Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea.

Background: Since Middle East respiratory syndrome (MERS) infection was first reported in 2012, many studies have analysed its transmissibility and severity. However, the methodology and results of these studies have varied, and there has been no systematic review of MERS. This study reviews the characteristics and associated risk factors of MERS.

Method: We searched international (PubMed, ScienceDirect, Cochrane) and Korean databases (DBpia, KISS) for English- or Korean-language articles using the terms "MERS" and "Middle East respiratory syndrome". Only human studies with > 20 participants were analysed to exclude studies with low representation. Epidemiologic studies with information on transmissibility and severity of MERS as well as studies containing MERS risk factors were included.

Result: A total of 59 studies were included. Most studies from Saudi Arabia reported higher mortality (22-69.2%) than those from South Korea (20.4%). While the R value in Saudi Arabia was < 1 in all but one study, in South Korea, the R value was 2.5-8.09 in the early stage and decreased to < 1 in the later stage. The incubation period was 4.5-5.2 days in Saudi Arabia and 6-7.8 days in South Korea. Duration from onset was 4-10 days to confirmation, 2.9-5.3 days to hospitalization, 11-17 days to death, and 14-20 days to discharge. Older age and concomitant disease were the most common factors related to MERS infection, severity, and mortality.

Conclusion: The transmissibility and severity of MERS differed by outbreak region and patient characteristics. Further studies assessing the risk of MERS should consider these factors.
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http://dx.doi.org/10.1186/s12889-018-5484-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5930778PMC
May 2018

The Effect of Dongeui Qigong for Prehypertension and Mild Essential Hypertension.

Evid Based Complement Alternat Med 2017 19;2017:4274538. Epub 2017 Oct 19.

Department of Internal Medicine, Dongeui Oriental Hospital of Dongeui University, Busan, Republic of Korea.

Although several previous studies have reported the effect of qigong on lowering blood pressure, rigorous trials are lacking. Studies evaluating the effect of qigong on prehypertension are also scarce. This study aimed to assess the effect of qigong on prehypertension and mild hypertension. Participants with prehypertension or mild hypertension were randomized to the Dongeui qigong group or a nontreated control group. In the qigong group, Dongeui qigong was administered 5 times/week for 12 weeks. The control group did not receive any intervention for blood pressure control. Fifty-two participants were included in this study. Even though diastolic blood pressure was significantly reduced in the qigong group after 8 weeks ( = 0.04) compared to baseline, the difference in change in blood pressure between the qigong and control groups was not significant. There were no significant differences in quality of life between the qigong and control groups. Dongeui qigong is not significantly effective in pre/mild hypertension compared with controls. This result could be due to a lack of effect of qigong or caused by other factors, such as the type of qigong, target symptoms, inappropriate sample size, and compliance of participants. . This trial is registered with KCT0001397 (Clinical Research Information Service).
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http://dx.doi.org/10.1155/2017/4274538DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5671714PMC
October 2017

Capsular serotypes, virulence-associated genes and antimicrobial susceptibility of Streptococcus suis isolates from pigs in Korea.

J Vet Med Sci 2017 Apr 1;79(4):780-787. Epub 2017 Mar 1.

Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon, 39660, Korea.

Streptococcus suis is an important pig pathogen with potential for human transmission. The serotype distributions and phenotypic characteristics vary over time and among regions; however, little is known about the characteristics of S. suis isolates in Korea. In this study, 240 S. suis isolates collected from pigs in Korea in 2009-2010 were serotyped by coagglutination tests, subsequently screened for three virulence-associated genes (mrp, epf and sly) and tested for antimicrobial susceptibility. As for 80 isolates, the serotypes of which were relevant to human infections, clonal complexes (CCs) were further identified by PCR. Serotype 3 was the most prevalent (15.8%), followed by serotype 2 (15.0%), with geographical variation for each serotype. Overall, 55.4% of the isolates carried mrp, whereas only 3.8% carried epf. CC25 was the most prevalent (41.3%) and was related to serotypes 2 and 9. The isolates showed higher susceptibility to ampicillin (93.4%) and ceftiofur (90.8%) than to the other antimicrobial agents tested. The highest resistance rate was observed to tetracycline (98.0%), followed by erythromycin (88.8%). In addition, the resistance to certain antimicrobials was significantly associated, in part, with virulence-associated genes or serotypes. Therefore, continuous characterization of S. suis is essential for the benefit of veterinary and human medicine.
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http://dx.doi.org/10.1292/jvms.16-0514DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5402202PMC
April 2017

Characterization of Salmonella enterica Serovar 4,[5],12:i:- Isolates from Korean Food Animals.

Foodborne Pathog Dis 2015 Sep 20;12(9):766-9. Epub 2015 Jul 20.

1 Animal and Plant Quarantine Agency , Anyang-si, Gyeonggi-do, Korea.

Salmonella enterica subspecies enterica serovar 4,[5],12:i:-, a monophasic variant of Salmonella Typhimurium, has emerged as one of the most common serotypes related to human salmonellosis. In this study, the 22 isolates of S. 4,[5],12:i:- from food animals were identified by a specific multiplex polymerase chain reaction between 2009 and 2012. The isolation rate of S. 4,[5],12:i:- accounted for 1.7% (22/1271) of Salmonella spp. isolates from food animal origins: more specifically, 7.6% (18/235) from pigs and 0.6% (4/686) from chickens. The predominant S. 4,[5],12:i:- isolates in Korea belonged to phage type DT193 (12/22) with ampicillin-streptomycin-sulfonamide-tetracycline (ASSuT) resistance pattern (9/22). The XbaI-pulsed-field gel electrophoresis (PFGE) analysis revealed 11 different pulsotypes, and the major X-1 pattern was shared by 8 isolates. The isolates belonging to pattern X-1 were further subdivided into three BlnI-PFGE patterns and four variable-number tandem-repeat analysis (MLVA) allele combinations. The combining of MLVA and PFGE data could be valuable in characterizing highly clonal strains and discriminating their epidemiological relationship.
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http://dx.doi.org/10.1089/fpd.2015.1947DOI Listing
September 2015

Preparation and Characteristics of SiO Coated Carbon Nanotubes with High Surface Area.

Nanomaterials (Basel) 2012 Jun 18;2(2):206-216. Epub 2012 Jun 18.

Fuel Cell Research Center, Korea Institute of Energy Research, Daejeon 305-343, Korea.

An easy method to synthesize SiO coated carbon nanotubes (SiO-CNT) through thermal decomposition of polycarbomethylsilane adsorbed on the surface of CNTs is reported. Physical properties of SiO-CNT samples depending on various Si contents and synthesis conditions are examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen isotherm, scanning electron microscope (SEM), and transmission electron microscope (TEM). Morphology of the SiO-CNT appears to be perfectly identical to that of the pristine CNT. It is confirmed that SiO is formed in a thin layer of approximately 1 nm thickness over the surface of CNTs. The specific surface area is significantly increased by the coating, because thin layer of SiO is highly porous. The surface properties such as porosity and thickness of SiO layers are found to be controlled by SiO contents and heat treatment conditions. The preparation method in this study is to provide useful nano-hybrid composite materials with multi-functional surface properties.
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http://dx.doi.org/10.3390/nano2020206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5327897PMC
June 2012

Detection and characterization of aparmycin-resistant Escherichia coli from humans in Korea.

Microb Drug Resist 2011 Dec 9;17(4):563-6. Epub 2011 Sep 9.

National Veterinary Research and Quarantine Service, Anyang, Republic of Korea.

To investigate apramycin resistance in humans in Korea, a total of 138 human Escherichia coli strains confirmed as gentamicin-resistant were collected from Korean Culture Collection Antimicrobial-Resistant Microbes. Apramycin resistance (minimum inhibitory concentrations ≥1,024 μg/ml) was observed in 16 (11.6%) of the 138 gentamicin-resistant E. coli (GREC) strains. Among the seven different kinds of aminoglycoside resistance genes tested, only four kinds were detected in the apramycin-resistant GREC strains: aac (3)-II, aac (3)-III, aac (3)-IV, and armA. The aac (3)-IV gene was found in all apramycin-resistant GREC strains, whereas aac(3)-II, aac(3)-III, and armA genes were detected in 8 (50.0%), 6 (37.5%), and 1 (6.3%) GREC strains resistant to apramycin, respectively. Of 16 apramycin-resistant GREC strains, transfer of apramycin resistance was observed in seven (43.8%), and co-transfer of resistance to other antimicrobials along with apramycin resistance was also found in four strains (25.0%) by broth mating. The results of this study suggest that more prudential use of apramycin in animals is needed.
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http://dx.doi.org/10.1089/mdr.2011.0052DOI Listing
December 2011

Prevalence and mechanisms of quinolone resistance among selected nontyphoid Salmonella isolated from food animals and humans in Korea.

Foodborne Pathog Dis 2011 Nov 30;8(11):1199-206. Epub 2011 Aug 30.

Division of Bacteriology, National Veterinary Research and Quarantine Service, Anyang, Gyeonggi-do, Republic of Korea.

The aim of this study was to investigate the prevalence and mechanism of quinolone resistance among selected nontyphoid Salmonella (NTS) isolates. A total of 1279 NTS isolated from food animals (n=692) and humans (n=587) between 1995 and 2009 were investigated by serotyping, antimicrobial susceptibility testing, screening for plasmid-mediated quinolone resistance (PMQR) genes qnr, aac(6')-Ib-cr, and qepA and mutations in the quinolone resistance-determining region (QRDR) of gyrA and parC by PCR, and DNA sequencing. Three hundred thirty (47.7%) of 692 animal isolates and 177 (30.2%) of 587 human isolates were resistant to nalidixic acid. Most animal (94.8%, 313/330) and human (99.4%, 176/177) NTS exhibited decreased ciprofloxacin susceptibility (minimum inhibitory concentration [MIC]: 0.125-2 mg/L). None of them carried qnr or qepA gene. However, aac(6')-Ib was identified in six animal isolates, of which four carried aac(6')-Ib-cr gene. Based on antimicrobial resistance profile, year of isolation, MIC for quinolones and fluoroquinolones, and isolation frequency of serotype, 114 animal and 83 human isolates were tested for QRDR mutations. All contained a single mutation within the QRDR of gyrA at either codon 87 or 83, and 41 of them contained an additional mutation in parC. The most prevalent mutation was Asp87-Tyr (n=107), followed by Asp87-Gly (n=28), Asp87-Asn (n=26), Ser83-Tyr (n=22), and Ser83-Phe (n=14). Point mutations in parC were observed outside the QRDR, which included 40 isolates with Thr57-Ser substitution and 1 Salmonella Typhimurium with a novel Glu51-Lys substitution. In conclusion, a point mutation within the QRDR of gyrA was primarily responsible for quinolone resistance and reduced susceptibility to fluoroquinolones in NTS in Korea. To our knowledge, this is the first report of occurrence of aac(6')-Ib-cr gene among NTS in Korea. The spread of NTS carrying aac(6')-Ib-cr is of serious concern and should be carefully monitored.
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http://dx.doi.org/10.1089/fpd.2011.0899DOI Listing
November 2011

Antimicrobial susceptibility testing of two Lawsonia intracellularis isolates associated with proliferative hemorrhagic enteropathy and porcine intestinal adenomatosis in South Korea.

Antimicrob Agents Chemother 2011 Sep 20;55(9):4451-3. Epub 2011 Jun 20.

Foreign Animal Disease Division, National Veterinary Research and Quarantine Service, Anyang-ro 175, Anyang-si 430-824, Republic of Korea.

This study represents the first published data on antimicrobial susceptibility of Asian isolates of Lawsonia intracellularis. We assessed MICs of 16 antimicrobials for two isolates of L. intracellularis recovered from diseased pigs in South Korea, one from a finisher pig with acute proliferative hemorrhagic enteropathy in 2002 and the other from a grower pig with porcine intestinal adenomatosis in 2010. Tylosin and tilmicosin were found to be the most active against L. intracellularis both intracellularly (MICs, 0.25 to 0.5 μg/ml and 0.125 μg/ml, respectively) and extracellularly (MICs, 0.25 to 0.5 μg/ml and 1 μg/ml, respectively).
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http://dx.doi.org/10.1128/AAC.00408-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165349PMC
September 2011

Differential identification of Salmonella enterica subsp. enterica serovar Gallinarum biovars Gallinarum and Pullorum based on polymorphic regions of glgC and speC genes.

Vet Microbiol 2011 Jan 1;147(1-2):181-5. Epub 2010 Jun 1.

National Veterinary Research & Quarantine Service, Ministry for Food, Agriculture, Forestry and Fisheries, Anyang, Gyeonggi, Republic of Korea.

Salmonella enterica subsp. enterica serovar Gallinarum biovars Gallinarum and Pullorum cause fowl typhoid and pullorum disease in avian species, respectively, and have been of considerable economic importance to the poultry industry in parts of the world. The definitive diagnosis of these diseases can be made only by isolation and identification of the causative agent. However, rapid identification of biovars Gallinarum and Pullorum is not easily feasible due to their common antigenic structure and genomic sequence similarity. We developed a duplex polymerase chain reaction (PCR) assay to identify and discriminate between strains of biovars Gallinarum and Pullorum. Duplex PCR primers were designed to target polymorphic regions of glgC and speC genes showing multiple mutations in the sequenced S. enterica subsp. enterica serovar Gallinarum 287/91 genome and were applied to the specific identification of biovars Gallinarum and Pullorum. Boiled lysates of 131 reference and field strains of Salmonella and other related Gram-negative bacteria were tested to validate the duplex PCR assay. All strains of biovars Gallinarum (n=53) and Pullorum (n=21) tested were correctly identified based on this assay (100% sensitivity) while the other strains (n=57) were PCR negative (100% specificity). These results demonstrate that a highly accurate biovar-specific duplex PCR assay can be performed for the rapid identification and discrimination of biovars Gallinarum and Pullorum from field isolates.
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http://dx.doi.org/10.1016/j.vetmic.2010.05.039DOI Listing
January 2011

Characterization of antimicrobial resistance of recent Salmonella enterica serovar Gallinarum isolates from chickens in South Korea.

Avian Pathol 2010 Jun;39(3):201-5

National Veterinary Research and Quarantine Service, Anyang, Gyeonggi, South Korea.

Salmonella enterica serovar Gallinarum isolates (n=105) from chickens in South Korea between 2002 and 2007 were tested for antimicrobial susceptibility by determining minimum inhibitory concentrations of 16 antimicrobials, and their predominant resistance profiles were genetically characterized. Most isolates (99/105; 94.3%) were resistant to nalidixic acid and resistant/intermediately resistant to fluoroquinolones, and 63.8% (67/105) of the isolates were resistant to three or more antimicrobials. Forty-two quinolone-resistant isolates, of which the quinolone resistance-determining regions of the gyrA genes were sequenced, contained a substitution of a Ser to a Phe or Tyr at position 83 (71.4%), or a substitution of an Asp to an Asn, Gly, or Tyr at position 87 (28.6%). Fifty-seven sulphamethoxazole-resistant isolates were tested for the presence of class 1 integrons by polymerase chain reaction, and their resistance gene cassettes were analysed by sequencing. Three different class 1 integrons containing the resistance-gene insert aadA (52.6%; n=30), aadB (12.3%; n=7), or aadB-aadA (12.3%; n=7) were identified. Most isolates harbouring the integron containing aadB-aadA displayed resistance to all three aminoglycosides tested and also showed increased resistance to fluoroquinolones. These findings suggest that fluoroquinolone resistance may be epidemiologically linked to multiple aminoglycoside resistance.
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http://dx.doi.org/10.1080/03079451003767261DOI Listing
June 2010

Antibiotic resistance patterns and detection of blaDHA-1 in Salmonella species isolates from chicken farms in South Korea.

Appl Environ Microbiol 2010 Jul 4;76(14):4760-4. Epub 2010 Jun 4.

Department of Infectious Diseases, Seoul National University, San 56-1, Kwanak-Ku, Seoul, South Korea.

Fifteen nonrepetitive ampicillin-resistant Salmonella spp. were identified among 91 Salmonella sp. isolates during nationwide surveillance of Salmonella in waste from 131 chicken farms during 2006 and 2007. Additional phenotyping and genetic characterization of these 15 isolates by using indicator cephalosporins demonstrated that resistance to ampicillin and reduced susceptibility to cefoxitin in three isolates was caused by TEM-1 and DHA-1 beta-lactamases. Plasmid profiling and Southern blot analysis of these three DHA-1-positive Salmonella serovar Indiana isolates and previously reported unrelated clinical isolates of DHA-1-positive Salmonella serovar Montevideo, Klebsiella pneumoniae, and Escherichia coli from humans and swine indicated the involvement of the large-size plasmid. Restriction enzyme digestion of the plasmids from the transconjugants showed variable restriction patterns except for the two Salmonella serovar Indiana isolates identified in this study. To the best of our knowledge, this is the first report of the presence of the DHA-1 gene among Salmonella spp. of animal origin.
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http://dx.doi.org/10.1128/AEM.02536-09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901715PMC
July 2010

Moxibustion for treating menopausal hot flashes: a randomized clinical trial.

Menopause 2009 Jul-Aug;16(4):660-5

Department of Medical Research, Korea Institute of Oriental Medicine, Daejeon, South Korea.

Objective: A hot flash is a general postmenopausal symptom experienced by approximately 75% of climacteric women. Women often turn to complementary and alternative medicines to relieve hot flashes. Moxibustion is one such medication. The aim of this study was to evaluate the effect of moxibustion on hot flashes in perimenopausal and postmenopausal women.

Methods: Fifty-one participants were randomly assigned into three groups, namely, moxibustion 1, moxibustion 2, and waiting list (control). The moxibustion groups received 14 sessions of moxibustion treatment for 4 weeks at acupuncture points. Our protocol was supported by evidence from clinical experts (Moxa 1) or published literature (Moxa 2), and we followed all participants for an additional 2 weeks after the end of the study. Our primary outcome measures were frequency and severity of hot flashes. Secondary outcome parameters included quality of life (Menopausal-Specific Quality of Life Scale) and Menopause Rating Scale.

Results: Fifty-one women participated in our study. By week 4, the difference in severity and frequency of hot flashes had become statistically significant between the treatment groups and the control participants. In addition, there was a statistically significant difference in Menopausal-Specific Quality of Life Scale scores between treatment group 2 and the other groups.

Conclusions: Our results suggest that moxibustion reduces both the frequency and severity of menopausal hot flashes as compared with those in control participants. We would recommend further studies with larger samples and possibly including placebo controls.
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http://dx.doi.org/10.1097/gme.0b013e318198cdf7DOI Listing
October 2009

Highly pathogenic avian influenza virus (H5N1) in domestic poultry and relationship with migratory birds, South Korea.

Emerg Infect Dis 2008 Mar;14(3):487-90

Ministry of Agriculture and Forestry, Anyang, South Korea.

During the 2006-2007 winter season in South Korea, several outbreaks of highly pathogenic avian influenza virus (H5N1) were confirmed among domestic poultry and in migratory bird habitats. Phylogenetic analysis showed that all isolates were closely related and that all belong to the A/bar-headed goose/Qinghai/5/2005-like lineage rather than the A/chicken/Korea/ES/2003-like lineage.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2570817PMC
http://dx.doi.org/10.3201/eid1403.070767DOI Listing
March 2008

Dissemination and tracking of Salmonella spp. in integrated broiler operation.

J Vet Sci 2007 Jun;8(2):155-61

National Veterinary Research and Quarantine Service, Ministry of Agriculture & Forestry, Anyang 430-824, Korea.

Controlling Salmonella in integrated broiler operation is complicated because there are numerous potential sources of Salmonella contamination, including chicks, feed, rodents, wild poultry operations, and the processing plant. The objective of this study was to investigate the distribution of Salmonella through all phases of two integrated broiler operations and to determine the key areas related to the control of all known sources of infection. Two different Salmonella serotypes were observed at integrated broiler chicken company A. S. enteritidis, the predominant company A isolate, was consistently found in the breeder farm, hatcheries, broiler farms, and chicken slaughterhouse. At company B, a total of six different serotypes, S. heidelberg, S. senftenberg, S. enteritidis, S. blockley, S. gallinarum, and S. virchow, were detected. Although S. heidelberg was not found in the broiler farms, it was consistently found in the breeder farm, hatcheries, and chicken slaughterhouse. In addition, S. enteritidis was found in the hatcheries, broiler farm, and chicken slaughterhouse. In order to obtain the genetic clonality, 22 S. enteritidis isolates were digested with XbaI and analyzed by pulsed-field gel electrohporesis (PFGE). A difference in the PFGE pattern was found to be related to the origin of the integrated broiler operation. These data support the critical need to control Salmonella in breeder farms and hatcheries, and demonstrate important points related to the control of infection in large-scale poultry operations of Korea.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872714PMC
http://dx.doi.org/10.4142/jvs.2007.8.2.155DOI Listing
June 2007

Enhancement of receptor-operated cation current and TRPC6 expression in arterial smooth muscle cells of deoxycorticosterone acetate-salt hypertensive rats.

J Hypertens 2007 Apr;25(4):809-17

Artificial Muscle Research Center, Departments of Physiology, College of Medicine, Konkuk University, Choongju, Korea.

Objectives: In deoxycorticosterone acetate (DOCA)-salt hypertensive rats, altered reactivity of blood vessels to vasoactive agonists is frequently associated with an elevation in blood pressure. Canonical transient receptor potential (TRPC) channels are believed to encode receptor-operated cation channels (ROC), the activation of which is involved in smooth muscle depolarization and vasoconstriction. The aims of the present study were to investigate whether the ROC current is increased in DOCA-hypertensive rats and determine whether aldosterone directly enhances the expression of TRPC.

Methods: The nystatin-perforated patch-clamp technique was used for the recording of receptor-stimulated ion currents in mesenteric arterial smooth muscle cells, which were enzymatically dispersed from sham-operated and DOCA-salt hypertensive rats. Expressions of TRPCs were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and by Western blot analysis.

Results: Receptor-stimulated currents activated by 5-hydroxytryptamine (serotonin) and norepinephrine were increased significantly in the mesenteric arterial smooth muscle cells of DOCA-salt hypertensive rats compared to sham-operated rats. Ion-substitution experiments revealed that the enhanced currents were cation currents (ROC currents). Enhanced expression of TRPC6 in mesenteric arteries from DOCA-salt hypertensive rats was demonstrated by real-time RT-PCR. Up-regulation of TRPC6 by aldosterone treatment in vitro was also observed in A7r5 cells by RT-PCR and in western blots.

Conclusion: These results suggest that aldosterone enhances TRPC6 expression and ROC currents in vascular smooth muscle cells, and that this may in turn contribute to altered vascular reactivity and to hypertension.
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http://dx.doi.org/10.1097/HJH.0b013e3280148312DOI Listing
April 2007

Serotonin depolarizes the membrane potential in rat mesenteric artery myocytes by decreasing voltage-gated K+ currents.

Biochem Biophys Res Commun 2006 Aug 28;347(2):468-76. Epub 2006 Jun 28.

Artificial Muscle Research Center, College of Medicine, Konkuk University 322 Danwol-dong, Choongju 380-701, Republic of Korea.

We hypothesized that voltage-gated K+ (Kv) currents regulate the resting membrane potential (Em), and that serotonin (5-HT) causes Em depolarization by reducing Kv currents in rat mesenteric artery smooth muscle cells (MASMCs). The resting Em was about -40 mV in the nystatin-perforated patch configuration, and the inhibition of Kv currents by 4-aminopyridine caused marked Em depolarization. The inhibition of Ca2+-activated K+ (KCa) currents had no effect on Em. 5-HT (1 microM) depolarized Em by approximately 11 mV and reduced the Kv currents to approximately 63% of the control at -20 mV. Similar 5-HT effects were observed with the conventional whole-cell configuration with a weak Ca2+ buffer in the pipette solution, but not with a strong Ca2+ buffer. In the presence of tetraethylammonium (1mM), 5-HT caused Em depolarization similar to the control condition. These results indicate that the resting Em is largely under the regulation of Kv currents in rat MASMCs, and that 5-HT depolarizes Em by reducing Kv currents in a [Ca2+]i-dependent manner.
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http://dx.doi.org/10.1016/j.bbrc.2006.06.116DOI Listing
August 2006

Ligusticum wallichi-induced vasorelaxation mediated by mitogen-activated protein kinase in rat aortic smooth muscle.

J Ethnopharmacol 2004 Feb;90(2-3):397-401

Department of Physiology, College of Medicine, Konkuk University, Danwol-dong 322, Chungju, Choong-Buk 380-701, South Korea.

Traditional herbal medicines have been widely used for the treatment of cardiovascular disorders in oriental countries. To determine the effects of Ch1LW, a chloroform extract of Ligusticum wallichi, on the vascular system, we studied changes in rat aortic smooth muscle in terms of magnitude of contraction and the activity of mitogen-activated protein kinases (MAPKs). Ch1LW inhibited the muscle contraction induced by norepinephrine (NE) in aortic strips. Ch1LW also abolished Ca2+-independent contraction evoked by 12-deoxyphorbol 13-isobutyrate in Ca2+-free medium containing 1 mM EGTA. Furthermore, western blotting analysis using phosphorylated MAPK antibodies showed that NE increased the activity of both extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK, which were inhibited by PD98059 and SB203580, blockers of ERK1/2 and p38 MAPK, respectively. Furthermore, treatment with Ch1LW significantly abolished NE-mediated activation of ERK1/2, whereas the activity of p38 MAPK was not affected by the extract. These results suggest that Ch1LW induces vasorelaxation in rat aortic smooth muscle, which may be mediated by the inhibition of ERK1/2 pathway, but not p38 MAPK.
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http://dx.doi.org/10.1016/j.jep.2003.11.003DOI Listing
February 2004

Direct block by bisindolylmaleimide of the voltage-dependent K+ currents of rat mesenteric arterial smooth muscle.

Eur J Pharmacol 2004 Jan;483(2-3):117-26

Department of Physiology, College of Medicine, Konkuk University, 322 Danwol-dong, Choongju 380-701, South Korea.

We investigated the effect of bisindolylmaleimide (I), a widely used protein kinase C (PKC) inhibitor, on the voltage-dependent K(+) (Kv) currents of rat mesenteric arterial smooth muscle cells using the whole-cell patch-clamp technique. Bisindolylmaleimide (I) reversibly and dose-dependently inhibited the Kv currents with an apparent K(d) value of 0.23+/-0.001 microM. The blockade was apparently through the acceleration of the decay rate of the Kv currents. The apparent rate constants of association and dissociation for bisindolylmaleimide (I) were 17.9+/-1.6 microM(-1) s(-1) and 4.1+/-1.5 s(-1), respectively. The inhibition of Kv current by bisindolylmaleimide (I) was steeply voltage-dependent between -30 and 0 mV (voltage range of channel activation). Bisindolylmaleimide (I) had no effect on the steady-state activation and inactivation of the Kv currents. Applications of trains of pulses at 1 or 2 Hz lead to a progressive increase in the bisindolylmaleimide (I)-blockade, and the recovery from bisindolylmaleimide (I)-block at -80 mV exhibited a time constant of 577.2+/-52.7 ms. Bisindolylmaleimide (V), an inactive analogue of bisindolylmaleimide (I), similarly inhibited the Kv currents with an apparent K(d) value of 1.48+/-0.004 microM, but other PKC inhibitor chelerythrine little affected the Kv currents. These results suggest that bisindolylmaleimide (I) directly inhibits the Kv currents of rat mesenteric arterial smooth muscle cells independently of PKC inhibition, in a state-, voltage-, time- and use-dependent manner.
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http://dx.doi.org/10.1016/j.ejphar.2003.10.028DOI Listing
January 2004
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