Resveratrol protects SH-SY5Y neuroblastoma cells from apoptosis induced by dopamine

Dopamine (DA) is an oxidant that may contribute to the degeneration of dopaminergic neurons. The present study demonstrates that DA-induced cytotoxicity in human-derived neurotypic cells, SH-SY5Y, is prevented by resveratrol, one of the major antioxidative constituents found in the skin of grapes. SH-SY5Y cells, a neuroblastoma cell line, treated with DA at 300 and 500 micrometer for 24 h underwent apoptotic death as determined by characteristic morphological features, including nuclear condensation, and loss of mitochondrial membrane potential (MMP). Flow cytometric analysis using Annexin V showed that DA can induce significant and severe apoptosis. Exposure to resveratrol (5 micrometer) for 1 h prior to the DA treatment attenuated DA-induced cytotoxicity, and rescued the loss of MMP. To investigate the apoptotic signaling pathways relevant to the restoration of DA-induced apoptosis by resveratrol, we carried out quantitative analysis of Bcl-2, caspase-3, and cleaved poly ADP-ribose polymerase (PARP) by immunoblot analysis. Resveratrol pretreatment led to a decrease in cleavage of PARP, an increase in the Bcl-2 protein, and activation of caspase-3. These results suggest that DA may be a potential oxidant of neuronal cells at biologically relevant concentrations. Resveratrol may protect SH-SY5Y cells against this cytotoxicity, reducing intracellular oxidative stress through canonical signal pathways of apoptosis and may be of biological importance in the prevention of a dopaminergic neurodegenerative disorder such as Parkinson disease.

Nucleotide Sequence and Phylogenetic Analysis of M and L Segment of Soochong Virus

Hantaan virus (HTNV) and Seoul virus (SEOV) have mainly been known as the cause of hemorrhagic fever with renal syndrome (HFRS) in Korea since HTNV has been isolated from Korean field mouse, Apodemus agrarius in 1976 and SEOV has been isolated from Rattus norvegicus in 1980. Soochong virus-1, -2, -3, -4 (SOOVs) were isolated from lung tissues of four Apodemus peninsulae captured on August 1997 at Mt. Gyebang in Hongcheon-gun, Mt. Gachil, Inje-gun, Gangwon Province, and in September 1998 at Mt. Deogyu, Muju-gun, Jeollabuk Province. Apodemus peninsulae is the second-most dominant field rodent species found throughout Korea. To determine phylogenetic analysis of SOOVs, we entirely identified nucleotide sequences of M and L segments. The length of M segment was 3,615 bp and L segment was 6,533 bp. SOOVs were diverged from HTNV by 22.7~23.3% and SEOV by 36.3~37.2%, in M segment. In addition, L segment was diverged from HTNV by 21.8~22.0% and SEOV by 30.3~30.5%. SOOVs sequence compared with Amur virus (AMRV) in M segment showed that SOOVs were different with AMRV about 14.6~16.2% in nucleotide sequences. Neighbor-joining phylogenetic analysis based on entire sequences of the M and L segment indicated that the SOOVs sequences present a separate lineage with HTNV, SEOV and AMRV. SOOVs constituted an individual cluster on the phylogenetic tree and they composed a phylogenic lineage separately. According to these data, SOOVs could be classified as a new hantavirus.

Retraction: Nucleotide Sequence and Phylogenetic Analysis of M and L Segment of Soochong Virus

No abstract available.

Epidemiology and Clinical Significance of Bacteriuria Caused by Vancomycin-Resistant Enterococci

BACKGROUND: Vancomycin-resistant enterococci (VRE) have been important pathogen of nosocomial infections and isolated most commonly from urine specimens. However, the clinical significance of VRE bacteriuria remains unknown. The objectives of this study are to describe the frequency, related factors and outcomes of VRE bacteriuria, and to compare epidemiologic data and outcomes between the subgroups: symptomatic urinary tract infection (UTI), asymptomatic bacteriuria, and colonization. MATERIALS AND METHODS: For patients with urine culture positive for VRE between August 1, 2002 and June 30, 2005, we collected clinical data and performed a retrospective analysis. According to Centers for Disease Control and Prevention (CDC), patients were classified as symptomatic UTI, asymptomatic bacteriuria, colonization and undetermined. RESULTS: Total 144 episodes (2.88%), in 58 patients, of 5,008 urine specimens were positive for VRE during the study period. Frequency of antimicrobial exposure history, especially 3rd generation cephalosporin, indwelling urinary catheter, and ICU stay at the time of culture was high in patients with VRE bacteriuria. In VRE bacteriuria, symptomatic UTI was only 24.5%. Instead the majority of the patients (71.4%) was colonized in urine with VRE or had asymptomatic bacteriuria. In comparison between symptomatic UTI group and combined group of asymptomatic bacteriuria and colonization, most demographic data and clinical features including hospital day and mortality had no significant difference except one, male sex. CONCLUSION: Most patients with VRE bacteriuria were classified as asymptomatic bacteriuria and colonization and only one-fourth of patients with VRE bacteriuria require antibiotic therapy. Therefore, clinicians should decide to initiate antibiotic therapy after consideration of clinical significance of VRE bacteriuria.

Epidemiology and Clinical Significance of Bacteriuria Caused by Vancomycin-Resistant Enterococci

BACKGROUND: Vancomycin-resistant enterococci (VRE) have been important pathogen of nosocomial infections and isolated most commonly from urine specimens. However, the clinical significance of VRE bacteriuria remains unknown. The objectives of this study are to describe the frequency, related factors and outcomes of VRE bacteriuria, and to compare epidemiologic data and outcomes between the subgroups: symptomatic urinary tract infection (UTI), asymptomatic bacteriuria, and colonization. MATERIALS AND METHODS: For patients with urine culture positive for VRE between August 1, 2002 and June 30, 2005, we collected clinical data and performed a retrospective analysis. According to Centers for Disease Control and Prevention (CDC), patients were classified as symptomatic UTI, asymptomatic bacteriuria, colonization and undetermined. RESULTS: Total 144 episodes (2.88%), in 58 patients, of 5,008 urine specimens were positive for VRE during the study period. Frequency of antimicrobial exposure history, especially 3rd generation cephalosporin, indwelling urinary catheter, and ICU stay at the time of culture was high in patients with VRE bacteriuria. In VRE bacteriuria, symptomatic UTI was only 24.5%. Instead the majority of the patients (71.4%) was colonized in urine with VRE or had asymptomatic bacteriuria. In comparison between symptomatic UTI group and combined group of asymptomatic bacteriuria and colonization, most demographic data and clinical features including hospital day and mortality had no significant difference except one, male sex. CONCLUSION: Most patients with VRE bacteriuria were classified as asymptomatic bacteriuria and colonization and only one-fourth of patients with VRE bacteriuria require antibiotic therapy. Therefore, clinicians should decide to initiate antibiotic therapy after consideration of clinical significance of VRE bacteriuria.

In vivo characterization of the integrin beta3 as a receptor for Hantaan virus cellular entry

Binding of viruses to cell surface molecules is an essential step in viral infection. In vitro studies suggested that the alpha v beta3 integrin receptor is the epithelial cell receptor for Hantaan virus (HTNV). Whether beta3 is in vivo the only or central cellular receptor for HTNV infection is not known. To investigate the role of beta3 integrin for cellular entry of HTNV, we established an HTNV infection model in newborn murine pups. Infected pups died at an average age of 14.2 +/- 1.1 days with high levels of viral antigen detected in their brain, lung, and kidney. Pre-injection of blocking monoclonal antibodies (mAb) specific for either beta3 or av prolonged survival significantly to a maximal average survival of 19.7 +/- 1.5 days (P<0.01) and 18.4 +/- 0.9 days (P<0.01), respectively. XT-199, a chemical blocker of the alpha v beta3 receptor also prolonged survival to 19.5 +/- 1.3 days (P<0.01). In contrast to these receptor blockades, anti-HTNV antibody was not only able to prolong survival, but 20% of infected pups achieved long-term survival. An anti-murine beta1 antibody comparatively prolonged survival (19.0 +/- 1.2 days), suggesting that HTNV infection is partly mediated through integrin beta1 receptors as well as through beta3 receptors in vivo. Our data demonstrate that the beta3 receptor is important for HTNV infection in vivo, but also suggest that HTNV may utilize additional receptors beyond beta3 for cellular entry within an organism.

Serological Characterization of Soochong and Muju Virus as New Serotype of Hantavirus

Apodemus agrarius, which accounts for three-fourths of the wild rodents, mainly inhabits in cultivated fields of Korea. Apodemus peninsulae and Eothenomys regulus are the second and third dominant species, respectively. Soochong virus (SOOV) from A. peninsulae and Puumala-related Muju virus (MUJV) from E. regulus were isolated in 1997 and 1998 in Korea, respectively. But serological characterizations of SOOV and MUJV were not identified clearly. Thus, in order to determine the serotypic classification, simultaneous cross-indirect immunofluorescent antibody (IFA) assay and cross-plaque reduction neutralization (PRN) test against four different hantaviruses were conducted with sera from 17 A. agrarius, 19 A. peninsulae, and 8 E. regulus strains. IFA titers of sera from A. agrarius and A. peninsulae were the highest to Hantaan virus (HTNV) and SOOV, respectively. However, most sera showed similar IFA titers to Seoul virus (SEOV). Therefore it was difficult to do serotyping using the sera from A. agrarius and A. peninsulae by IFA. In case of sera of E. regulus, IFA titers to Puumala virus (PUUV) were higher than HTNV, SOOV and SEOV. Cross-PRN result of A. agrarius to HTNV, SOOV, SEOV and PUUV was 6,890, 5,120, 110 and 30, respectively. In case of A. peninsulae, the mean PRN titer was the highest to SOOV (1:6,820) and those to HTNV, SEOV and PUUV were 1,580, 100 and 30, respectively. The mean PRN titers of E. regulus to HTNV, SOOV, SEOV and PUUV were 70, 10, 80 and 640. SOOV and MUJV could be distinguished from HTNV and SEOV by cross-PRNT. These results demonstrate that SOOV and MUJV could be classified as new serotype of hantavirus.

Molecular Genetic Characterization of Clinical Isolates of Streptococcus pyogenes / 대한진단검사의학회지

BACKGROUND: Group A streptococcus (Streptococcus pyogenes) is the most common cause of bacterial pharyngitis and an important cause of a variety of suppurative and nonsuppurative diseases. The molecular genetic analysis of group A streptococci in clinical isolates is rarely reported in Korea. In this study, molecular genetic analysis using serotyping and emm sequence analysis, testing the presence of the SpeA and SpeB gene, and the determination of an antimicrobial resistance pattern were investigated. METHODS: Sixty nine strains of S. pyogenes from clinical isolates in Korea during 1999-2002 were examined by T agglutination, serum opacity reaction, and emm sequence analysis. Also investigated were antimicrobial susceptibility and the frequency of SpeA and SpeB genes. RESULTS: The antibiotic resistance rates for S. pyogenes isolates were shown at 28.9% of erythromycin, 14.2% of ampicillin, 9.5% of chloramphenicol, and 6.3% of levofloxacin. However, all strains were susceptible to penicillin, vancomycin, and teicoplanin. By T agglutination typing, forty-one (59.4%) among sixty-nine isolates were identified as T28 (13%), T6 (13%), T1 (10%), T12 (8.7%), T4 (4%), T5/27/44 (4%), T3/B3264 (2.9%), T11/12 (1.4%), and TB3264 (1.4%). Thirty-five (50.7%) among sixty nine isolates were positive in serum opacity reaction. The SpeB gene showed positive in all strains but the SpeA gene in eleven (15.9%) strains. By emm gene sequence analysis, forty-seven (68.1%) CONCLUSIONS: Our data showed that antimicrobial resistance of clinical isolates to erythromycin were higher than those reported from the United States and Europe, and emm genotyping could be used for a reliable and efficient typing method.

Effects of Mumps Virus Nucleocapsid Protein on the Viral Replication and Apoptosis in VeroE6 Cells

Apoptosis, as a part of the natural defense mechanisms that protect against viral infection, plays a vital role in the pathogenic mechanisms. It also plays a key role in the pathogenesis of diseases including many viral diseases. Mechanisms of virus-induced apoptosis are not completely understood because of the complexity of the underlying biochemical cascades and all of the participating host factors. Mumps virus belongs to the genus Rubulavirus in the family Paramyxoviridae. It contains single stranded RNA genome with negative polarity. It was observed that mumps virus induced apoptosis in VeroE6 cells, and adsorption and penetration of mumps virus to cell membrane alone were not sufficient for the induction of cell death. When mumps virus was superinfected onto nucleocapsid protein (NP) expressing VeroE6 cells, cell viability and facterial titer were maintained until 13 and 12 day, respectively. The levels of p53, Bax, and Bcl-2 were increased in NP-expressing VeroE6 cells, and the increase in Bax, and Bcl-2 was outstanding. It was observed that NP protein did not directly affect the efficiency of the infection of mumps virus in NP-expressing VeroE6 cells. The levels of p53, and Bax were decreased in both mock-infected VeroE6 cells and NP-expressing VeroE6 cells infected with mumps virus. However, the Bcl-2 level was little affected by the virus infection.

Production and Characterization of Monoclonal Antibodies to Mumps Virus Isolated in Korea

Classical mumps patients develop bilateral or less commonly unilateral parotitis. Mumps virus belongs to the genus Rubulavirus in the family Paramyxoviridae. It contains single stranded RNA genome with negative polarity. To characterize the antigenicity of mumps virus isolated in Korea, nineteen hybridoma cell lines producing monoclonal antibodies to mumps virus were established by fusion of Sp2/0-Ag14 mouse myeloma cells with spleen cells of mice immunized with mumps virus strain 98-40. The specificity of these monoclonal antibodies was established by immunofluorescence microscopy and immunoblotting analysis. Fifteen out of nineteen hybridoma cell lines secreted IgG monoclonal antibodies (MAbs) against mumps virus, and the remaining four secreted IgM. The isotypes of thirteen clones of 19 MAbs were IgG1, two were IgG2a, and four were IgM. Eight MAbs reacted with a 68 kDa nucleocapsid protein, six MAbs reacted with a 46 kDa phosphoprotein, and five MAbs reacted with a 42 kDa matrix protein.

Epidemilogical Study on Orientia tsutsugamushi Infection of Wild Rodents in Korea

This study was carried out to determine the seropositivity for Orientia tsutsugamushi infection among wild rodents captured in farms and mountains of Korea. A total 965 wild rodents of 7 species and 48 Crocidura laciura were captured in farms and mountains of 6 province during 1997~2000 in Korea. Serological evidence for O. tsutsugamushi infection was obtained using O. tsutsugamushi antigens by indirect immunofluorescent antibody technique (IFA). Four hundred eighty four Apodemus agrariusus, 246 Apodemus peninsulae, 179 Eothenomys regulus, 44 Microtus fortis, 6 Micromys minutus, 5 Mus musculus, and 1 Cricetula triton were captured in Gyeonggi, Gangwon, Chungnam, Gyeongbuk, Gyeongnam, and Jeonbuk province. Among them, 59 (12.2%) A. agrariusus, 22 (8.9%) A. peninsulae, 12 (6.7%) E. regulus, 5 (11.4%) M. fortis and 1 (16.7%) M. minutus were IF antibody positive against O. tsutsugamushi Gilliam or Karp strain.

Seroepidemiologic Analysis of Acute Febrile Illness in Korea during 1997~1998

Hemorrhagic fever with renal syndrome (HFRS), scrub typhus, murine typhus and leptospirosis have been the principal acute febrile diseases in Korea for many years. To evaluate the seroepidemiologic patterns of the acute febrile illness, sera collected from 4,503 patients in 1997~1998 were examined for antibodies against Hantaan virus, Orientia tsutsugamushi and Rickettsia typhi by indirect immunofluorescent antibody technique (IFA) and macroscopic agglutination test for Leptospira interogans. Seropositive cases for Orientia tsutsugamushi, Rickettsia typhi, Leptospira interogans and Hantaan virus were 261 (12.4%), 242 (11.5%), 11 (0.5%), and 250 (11.9%) in 1997, and 415 (17.3%), 273 (11.4%), 16 (0.7%), and 357 (14.9%) in 1998, respectively. Male was affected more frequently by HFRS and leptospirosis while scrub typhus was more prevalent in female. Old age group was more susceptible to the acute febrile diseases. Most positive cases were occurred during October and November for scrub typhus, and during November and December for HFRS. These results showed similar patterns with previous epidemiological data obtained during recent several years, except the single scrub typhus epidemic in 1998, and implied that no significant changes occurred in ecologic system for acute febrile diseases in Korea.

Seroprevalence and Phylogenetic Analysis of Orientia tsutsugamushi from Apodemus peninsulae in Korea

To investigate the seroprevalence of the Orientia tsutsugamushi infection of Apodemus peninsulae and genomic variations in O. tsutsugamushi isolates, 246 A. peninsulae were trapped in 14 mountainous areas approximately 500 meter above sea level in Korea during the period of 1997 and 2000. Seropositive rate of O. tsutsugamushi among A. peninsulae was 31.8% in Kyunggi, 8.2% in Chunbuk and 7.1% in Kangwon provinces by microimmunofluorescent test. The 56 kDa protein gene was amplified by PCR in the spleens of seropositive A. peninsulae. Two amplicons from seropositive A. peninsulae were sequenced and their phylogeny was analysed on the basis of sequence homology. The 56 kDa genes of A. peninsulae 98-12 strain and A. peninsulae 98-16 strain showed 98.7% nucleotide homology and 96.6% amino acid similarity. A. peninsulae 98-12 and A. peninsulae 98-16 strain were related to Kuroki, Boryong and Karp strains showing 93.3~92.2%, and 87.1~84.6% homologies in nucleotide and amino acids levels, respectively. In the phylogenetic analysis, A. peninsulae 98-12 and A. peninsulae 98-16 strain formed a distinct group with Boryong, Kuroki and Nishino strains and were clearly distinguished from other genetic groups. The results suggest that A. peninsulae might be an important reservoir of O. tsutsugamushi in Korea.

Seropositive rate of Orientia tsutsugamushi in Tamias sibiricus from Korea

Among wild chipmunks, Tamias sibiricus, captured in Kyunggi and Kangwon province in Korea, 1997, seropositivity for Orientia tsutsugamushi was determined. Serological test for Orientia tsutsugamushi infection was performed using indirect immunofluorescent antibody technique (IFA). Of 243 wild chipmunks, 61 against Gilliam strain and 64 against Karp strain of Orientia tsutsugamushi were IFA positive. Seropositivity against Gilliam strain was shown 33.3% in Kyunggi and 23.5% in Kangwon province, and against Karp strain was shown 33.3% and 25.4%, respectively.

Isolation of Apodemus peninsulae-borne Hantavirus and Cimparison of Molecular Biological Characteristics

Two distinct hantaviruses have been isolated from Apodemus agrarius in 1976 and Rattus norvegicus in 1980 in Korea. Since our serosurveys conducted in 1994, a genetically distinct hantavirus from Apodemus peninsulae has been investigated. To isolate hantavirus from A. peninsulae captured in Korea, the lung homogenate of seropositive A. peninsulae inoculted Vero E6 cells. Viral antigen was detected in a progressively higher percentage of cells with subsequent passage after 80 days postinoculation. The new isolate from seropositive Apodemus peninsulae was designated Suchong virus after Suchong valley located in northeastern region of South Korea. Comparing with hantaan virus 76-118 strain, Suchong virus-1, 2, 3 and 4 showed the similarity of 71.0~91.8% at nucleotide and 90.9~94.8% at amino acid sequences in 231 nucleotides region of M segment, and the similarity of 75.1~81.0% at nucleotide and 97.5~100% at amino acid sequences in 237 nucleotides of S segment.

Sequence Analysis of Rubella Viruses Isolated in Korean and Expression of Rubella Specific Gene

During the recent epidemic period (1995~1996), seven strains of rubella virus were isolated in Korea. To analyze phylogenetic relationship between seven Korean strains and rubella virus strains from other different geographical areas, structural genes (E1, E2 and C) of Korean strains were enzymatically amplified and automatically sequenced. The sequence similarities of the E1, E2 and C genes of the cosmopolitan types were 95.8~98.1%, 92.6~99.2% and 96.4~99.3% based on 1,441, 122 and 139 nucleotides and 96.9~98.5%, 90~100% and 97.8~100% based on 480, 40 and 46 amino acids compared to the sequences of strain RA27/3, respectively. In contrast, the sequence similarities of the E1, E2 and C genes of the Asian types were 91.5~92.1%, 83.6~88.5% and 91.4% based on nucleotides ad 96.9~97.7%, 85.5% and 97.8% based on amino acids compared to the sequences of strain RA27/3. respectively. However, immunodominent epitopes of the E1 gene of the cosmopolitan and Asian types were well conserved, and the growth patterns in cell culture and immunofluorescent antibody titers in cross-reaction test showed no differences between two different types. In phylogenetic analysis based on nucleotide sequences of each gene regions, the comopolitan and Asian types formed tow distinct phylogenetic lineages. These data showed two distinct genotypes of rubella viruses cocirculated in Korea, but no significant differences in the antigenicity of two different rubella virus strains were found.

Chronic Chlamydia pneumoniae Infection as a Risk Factor for Acute Myocardial Infarction in Korea

BACKGROUND AND OBJECTIVES: To evaluate the association between chronic infection with Chlamydia pneumoniae, as measured by Immunoglobulin G and A, and acute myocardial infarction (AMI) in Korea. MATERIALS AND METHODS: A total of 136 patients [normal control 65 cases (male:female 27:8, mean age 55.1+/-11.7 years), AMI 71 cases (male:female 54:17, mean age 58.9+/-12.7 years)] had immunoglobulin G, A, and M antibody titers measured against Chlamydia pneumoniae by microimmunoflorescence assay and had coronary angiography performed. We investigated the incidence of major adverse cardiac events (MACE) at 6 month follow-up. Controls were defined as patients with no significant stenosis on coronary angiography. RESULTS: 1) AMI patients were more likely to be male (76.1: 41.5%) and smokers (67.6: 16.9%) compared with the controls. >2) In AMI patients, there was a weak correlation with IgG and IgA antibody titers (r=0.39, p=0.001).> 3) After adjusting for gender and smoking status, IgG and IgA antibody titers were similar between two groups.> 4) Increased IgG and IgA titers did not affect the MACE during follow-up. CONCLUSION: Chronic Chlamydia pneumoniae infection detected by immunoglobulin assay is not significantly associated with AMI. Further studies, such as polymerase chain reaction, immunocytochemistry, or culture of the atheromatous plaques, are needed to better define the association.

Establishment of a Screenig Test System for Early Diagnosis of Hepatocellular Carcinoma in High-Risk Patients and the Evaluation of Its Effectiveness / 대한암학회지

PURPOSE: To evaluate the effectiveness of clinic-based screening program for early detection of hepatocellular carcinoma (HCC) and to assess the risk factors of HCC in Korea. MATERIALS AND METHODS: The data of 14,259 patients who had ultrasonography (US) due to chronic liver diseases were collected into a data base program from 1990 to 1998. RESULTS: A total of 4,339 patients were enrolled who had repeated US. 237 patients were diagnosed as HCC during follow-up (mean 33 months). The tumor size detected by screening within a 6-months interval was significantly smaller than that of a longer interval (2.7 cm vs 3.9 cm, P<0.01). The smaller the tumor was at detection, the longer the survival time was. Only 29.9% of HCC patients had an elevated serum alpha-fetoprotein (alphaFP) level above 400 ng/ml. Multivariate analysis showed liver cirrhosis, chronic hepatitis B or C and old age over 40 years to be significantly associated with an increased risk of HCC. CONCLUSION: The US screening within a 6-months interval is beneficial to high-risk patients over 40 years old through the early detection of HCC and prolonged survival. According to the risk factors, the necessity for screening test and proper interval should be reconsidered.

Molecular Epidemiology of Korean Strains of Hepatitis A Virus / 대한간학회지

BACKGROUND/AIMS: Studies of genotypes and changes in nucleotide and amino acid sequences of hepatitis A virus (HAV) may provide valuable information on the epidemiological aspects of a particular region. In Korea the prevalence of anti-HAV in the 1 - 20 year age group declined from 60% in 1980 to 9% in 1995. As a result this age group has a high risk of HAV infection. Actually over 1,500 cases of clinically overt hepatitis A occurred in 1998 while few cases of clinical hepatitis A had been reported until the early 1990s. The aims of this study are to determine the genotypes of HAV which have been circulating in Korea and to define the phylogenetic relationships of geographically defined isolates. METHOD: From 1994 - 1998 a total of 18 serum specimens was obtained from patients in Korea with sporadic form acute hepatitis A. The HAV nucleic acid from serum specimens was subjected to genomic sequence analysis following viral RNA extraction, reverse transcription and amplification of the cDNA by PCR. DNA sequencing was performed in both directions of each PCR product. RESULTS: All isolates clustered within the subgenotype IA irrespective of the geographic locations and timing of the clinical hepatitis. Among 18 Korean isolates, 9 isolates had 2 amino acid sequence changes and 2 isolates had 1 amino acid sequence change. These changes in the amino acid sequences are unique and have never been reported in HAV subgenotype IA. CONCLUSIONS: All isolated HAV had genotype (IA). Eleven of 18 isolates had unique changes in amino acid sequences. These data indicate that the endemic HAV has been circulating in Korea over a long period of time.

Prevalence of Leptospira interrogans in Wild Rodents in Korea

Leptospirosis has been known as endemic disease in Korea since 1984. Wild rodent, mostly Apodemus agrarius, has been known as an important source of leptospiral infection especially in rainy circumstances in harvest reason of rural area. The infection rates of Leptospira interrogans in field rodents, Apodemus agrarius, was investigated by culture and PCR detection of leptospiral DNA, and compared with previous data. Furthermore, the serogroup and serovar were investigated. Two hundred twenty two Apodemus agrarius were captured during October to December 1996. Spirohaetes were isolated from 22 (9.9%) and leptospiral DNA was detected in an additional six rodents (12.6%). Subsequent cross-agglutinin absorption test, monoclonal antibody reactivity classified 21 cultures among 22 isolates as Leptospira interrogans serogroup Icterohemorrhagiae serovar lai. The above data did not differ from previous survey in 1984 to 1987. There was no significant change of Leptospira interrogans infection in field rodents in Korea.