Functional Profiling of Human MeCP2 by Automated Data Comparison Analysis and Computerized Expression Pathway Modeling / 대한의료정보학회지

OBJECTIVES: Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous epigenetic factor that represses gene expression by modifying chromatin. Mutations in the MeCP2 gene cause Rett syndrome, a progressive neurodevelopmental disorder. Recent studies also have shown that MeCP2 plays a role in carcinogenesis. Specifically, functional ablation of MeCP2 suppresses cell growth and leads to the proliferation of cancer cells. However, MeCP2's function in adult tissues remains poorly understood. We utilized a weight matrix-based comparison software to identify transcription factor binding site (TFBS) of MeCP2-regulated genes, which were recognized by cDNA microarray analysis. METHODS: MeCP2 expression was silenced using annealed siRNA in HEK293 cells, and then a cDNA microarray analysis was performed. Functional analysis was carried out, and transcriptional levels in target genes regulated by MeCP2 were investigated. TFBS analysis was done within genes selected by the cDNA microarray analysis, using a weight matrix-based program and the TRANSFAC 6.0 database. RESULTS: Among the differentially expressed genes with a change in expression greater than two-fold, 189 genes were up-regulated and 91 genes were down-regulated. Genes related to apoptosis and cell proliferation (JUN, FOSL2, CYR61, SKIL, ATF3, BMABI, BMPR2, RERE, and FALZ) were highly up-regulated. Genes with anti-apoptotic and anti-proliferative functions (HNRPA0, HIS1, and FOXC1) were down-regulated. Using TFBS analysis within putative promoters of novel candidate target genes of MeCP2, disease-related transcription factors were identified. CONCLUSIONS: The present results provide insights into the new target genes regulated by MeCP2 under epigenetic control. This information will be valuable for further studies aimed at clarifying the pathogenesis of Rett syndrome and neoplastic diseases.

Functional Profiling of Human MeCP2 by Automated Data Comparison Analysis and Computerized Expression Pathway Modeling / 대한의료정보학회지

OBJECTIVES: Methyl-CpG binding protein 2 (MeCP2) is a ubiquitous epigenetic factor that represses gene expression by modifying chromatin. Mutations in the MeCP2 gene cause Rett syndrome, a progressive neurodevelopmental disorder. Recent studies also have shown that MeCP2 plays a role in carcinogenesis. Specifically, functional ablation of MeCP2 suppresses cell growth and leads to the proliferation of cancer cells. However, MeCP2's function in adult tissues remains poorly understood. We utilized a weight matrix-based comparison software to identify transcription factor binding site (TFBS) of MeCP2-regulated genes, which were recognized by cDNA microarray analysis. METHODS: MeCP2 expression was silenced using annealed siRNA in HEK293 cells, and then a cDNA microarray analysis was performed. Functional analysis was carried out, and transcriptional levels in target genes regulated by MeCP2 were investigated. TFBS analysis was done within genes selected by the cDNA microarray analysis, using a weight matrix-based program and the TRANSFAC 6.0 database. RESULTS: Among the differentially expressed genes with a change in expression greater than two-fold, 189 genes were up-regulated and 91 genes were down-regulated. Genes related to apoptosis and cell proliferation (JUN, FOSL2, CYR61, SKIL, ATF3, BMABI, BMPR2, RERE, and FALZ) were highly up-regulated. Genes with anti-apoptotic and anti-proliferative functions (HNRPA0, HIS1, and FOXC1) were down-regulated. Using TFBS analysis within putative promoters of novel candidate target genes of MeCP2, disease-related transcription factors were identified. CONCLUSIONS: The present results provide insights into the new target genes regulated by MeCP2 under epigenetic control. This information will be valuable for further studies aimed at clarifying the pathogenesis of Rett syndrome and neoplastic diseases.

Acute Effects of Capsaicin on Proopioimelanocortin mRNA Levels in the Arcuate Nucleus of Sprague-Dawley Rats

OBJECTIVE: Capsaicin, a noxious stimulant and main component of the hot flavor of red peppers, has an analgesic effect when administered to humans. We investigated the expression of proopioimelanocortin (POMC) mRNA in the arcuate nucleus of Sprague-Dawley (SD) rats after administering capsaicin, hypothesizing that administering capsaicin activates the central opioid system. METHODS: SD rats were divided randomly into two groups; one group received a saline injection and the other received a capsaicin injection. The POMC mRNA level in the arcuate nucleus of the hypothalamus was measured by the reverse transcription-polymerase chain reaction at 0, 20, 40, 60, and 120 minutes after capsaicin administration. RESULTS: Capsaicin administration resulted in a significantly increased POMC mRNA level, compared to that in saline-treated rats at the 20-minute time point (t=-4.445, p=0.001). However, no significant group differences were observed at other times (t=-1.886, p=0.089; t= -0.973, p=0.353; t=-2.193, p=0.053 for 40, 60, and 120 minutes, respectively). CONCLUSION: The analgesic effect of capsaicin might be associated with increased activity of the cerebral opioid system. This finding suggests that capsaicin acted for nociception and analgesia and could affect alcohol-intake behavior, which might further imply that a food culture could affect drinking behavior.

COCAW: A Genome-wide Pattern Search System for Designing Microbial Probes

A few bioinformatics tools have been used to find out conserved regions as probes. We have developed a system based on a heuristic method with web interfaces to find out conserved regions against microbial genomes. The system runs in real time by using relative entropy in limited narrow regions and detecting similar regions between pair regions with local alignment. The system could be useful to find out conserved regions as genome-wide scale.

A Study of the Reliability and Validity of the Korean Version of the Penn Alcohol Craving Scale for Alcohol-Dependent Patients

OBJECTIVE: The Penn Alcohol Craving Scale (PACS) is a stronger predictor of subsequent drinking and relapse of alcohol dependence that can be administered more quickly and easily than other craving scales. The goal of this study was to develop the Korean version of the Penn Alcohol Craving Scale (PACS-K). METHODS: To examine the psychometric properties of the PACS-K, responses were chosen from 80 patients admitted to a treatment facility for alcohol dependence. RESULTS: The PACS-K possesses good psychometric properties, as assessed by Cronbach's alpha estimates (Cronbach's alpha=0.91). The test-retest reliability of the PACS-K showed high correlation (p<0.01) when the retest interval was 1 day. When the validity of the PACS-K was investigated using correlation analysis with two other craving scales (the Obsessive Compulsive Drinking Scale (OCDS) and the Visual Analogue Scale (VAS), high correlations were obtained between total PACS scores and total OCDS scores, and between total PACS scores and VAS scores (p<0.01, respectively). CONCLUSION: The PACS-K is a reliable and valid measure of alcohol cravings, and it could be useful for predicting which individuals are at risk for subsequent relapse.

The Study on Reliability and Validity of Korean Alcohol Urge Questionnaire(AUQ-K) for Alcohol Dependence

OBJECTIVES: The Alcohol Urge Questionnaire(AUQ) has been used in alcohol dependence treatment and research. The goal of this study is to develop of the Korean Alcohol Urge Questionnaire(AUQ-K). METHODS: To examine the AUQ-K's psychometric properties, responses from 104 patients admitted in alcohol dependence treatment facility were investigated. RESULTS: The internal consistency of the 8-item AUQ-K, measured by coefficient alpha, was high(Cronbach's alpha =0.78). AUQ-K scores showed significant correlation when the retest interval was 1 day(p<0.01). The AUQ-K's validity was investigated using correlational analyses with two other craving scales[the Obsessive Compulsive Drinking Scale(OCDS) and the Visual Analogue Scale(VAS)]. The high correlations were obtained between total AUQ-K scores and total OCDS scores, and between total AUQ-K scores and the VAS scores(p<0.01, respectively). CONCLUSION: The AUQ-K is a reliable and valid short scale for measurement of self-reported alcohol craving. This scale may offer significant advantages over existing single-item measures of alcohol craving in the fields of alcohol dependence treatment and research.

Mutations of CAPN3 in Korean Patients with Limb-Girdle Muscular Dystrophy

The limb-girdle muscular dystrophy type 2A (LGMD2A) is a recessively inherited disease caused by a mutation of the calpain 3 gene (CAPN3), and is considered one of the most prevalent subtypes of limb-girdle muscular dystrophy (LGMD). In this study, we aimed to identify CAPN3 mutations and to characterize the phenotype of Korean patients with LGMD2A. Among 35 patients with LGMD, four patients, who showed calpain 3 deficiency on western blot analysis, were analyzed in this study. Total RNA extracted from frozen muscle tissue was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using six primer pairs covering all coding sequences of CAPN3, and direct sequencing was performed. Clinical and pathological features of the patients were also reviewed. We found four different mutations in five alleles from three patients. Of the pathogenic mutations identified, two were novel (c.2125T>C and c.2355-2357delTTC), and the others had been reported elsewhere (c.440G>C, c.1076C>T). All patients showed a high CK level with predominant proximal leg weakness, and the onset was in their childhood except for one patient. Among two novel CAPN3 mutations, one was a missense mutation (c.2125T>C [p.709Ser>Pro]), and the other was a small in-frame deletion causing omission of a single amino acid (c.2355-2357delTTC [p.786delPhe]). The clinical features of our patients were generally compatible with the characteristics of LGMD2A patients described in the previous studies.

Change of the Expression of Human Telomerase Reverse Transcriptase mRNA and Human Telomerase RNA after Cisplatin and 5-Fluorouracil Exposure in Head and Neck Squamous Cell Carcinoma Cell Lines

Telomerase activity appears to be associated with cell immortalization and malignant progression. Understanding how telomerase activity is regulated in vivo is important not only for understanding the molecular biology of telomerase but also for the potential clinical application of anticancer drugs. This study evaluated telomerase activity and quantified the expression of human telomerase reverse transcriptase (hTERT) mRNA and human telomerase RNA (hTR) using a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method before and after the exposure of cisplatin and 5-fluorouracil (5-FU) in two head and neck squamous cell carcinoma (HNSCC) cell lines. Two human HNSCC cell lines (PNUH-12 and SNU-899) were studied. Cell cytotoxicity, the change of telomerase activity, and hTERT mRNA and hTR expression by 5-FU and cisplatin exposure were assessed by MTT assay, TRAP assay, and real-time RT-PCR, respectively. In two cell lines, after cisplatin exposure, the telomerase activity and hTERT mRNA expression decreased, but hTR expression in- creased according to the concentration of drug. However, in both cell lines, the telomerase activity and hTR did not show any significant change after 5-FU treatment, but the expression of hTERT mRNA decreased. These results suggest that there may be other important regulating mechanism except hTERT mRNA as the regulation factor of telomerase activity in HNSCC cell lines.

A Study on Relapse Predictors in Korean Alcohol-Dependent Patients: A 24 Weeks Follow up Study

OBJECTIVES: The aim of this prospective study is to investigate predictors estimating relapse in Korean alcohol-dependent patients using variables like alcohol history, drinking craving, treatment motivation and insight. METHODS: Alcohol dependent patients(N=48) who completed questionnaires about sociodemographic variables and drinking history, Timeline Follow-Back(TLFB), Obsessive-Compulsive Drinking Scale(OCSD), Alcohol Urge Questionnaire(AUQ), Pennsylvania Alcohol Craving Scale(PACS), University of Rhode Island Change Assessment(URICA), Hanil Alcohol Insight Scale(HAIS) were followed-up for 24weeks. Subjects who drank heavily(5 standard drinking or more/day) or were not followed up anymore were classified as the relapse group. We used logistic regression analysis with backward elimination of SPSS PC+11.5 to investigate relapse estimate predictors. RESULTS: Average drinking amount per drinking day for last 1 year and HAIS score were predictors of relapse in alcohol-dependent patients. CONCLUSIONS: Our findings suggest that therapist should give more attention to alcohol-dependent patients who had more drinks per drinking day for last 1 year and had lower insight level.

Diagnostic mutational analysis of MECP2 in Korean patients with Rett syndrome

Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder affecting 1 per 10,000- 15,000 female births worldwide. The disease-causing gene has been identified as MECP2 (methyl- CpG-binding protein 2). In this study, we performed diagnostic mutational analysis of the MECP2 gene in RTT patients. Four exons and a putative promoter of the MECP2 gene were analyzed from the peripheral blood of 43 Korean patients with Rett syndrome by PCR-RFLP and direct sequencing. Mutations were detected in the MECP2 gene in approximately 60.5% of patients (26 cases/43 cases). The mutations consisted of 14 different types, including 9 missense mutations, 4 nonsense mutations and 1 frameshift mutation. Of these, three mutations (G161E, T311M, p385fsX409) were newly identified and were determined to be disease-causing mutations by PCR- RFLP and direct sequencing analysis. Most of the mutations were located within MBD (42.3%) and TRD (50%). T158M, R270X, and R306C mutations were identified at a high frequency. Additionally, an intronic SNP (IVS3+23C>G) was newly identified in three of the patients. IVS3+23C>G may be a disease-related and Korea-specific SNP for RTT. L100V and A201V are apparently disease-causing mutations in Korean RTT, contrary to previous studies. Disease-causing mutations and polymorphisms are important tools for diagnosing RTT in Koreans. The experimental procedures used in this study should be considered for clinical molecular biologic diagnosis.

Mutations and Polymorphims of MECP2 Gene in Rett Syndrome / 대한산부인과학회지

OBJECTIVE: Rett syndrome (RTT) is a severe progressive neurodevelopmental disorder affecting primarily females by mutations in MECP2 gene. The aim of this study was to compare the pattern of mutations in MECP2 gene in Korean RTT with worldwide reports. METHODS: Six girls clinically diagnosed as RTT from April 2001 to March 2003 were recruited. Diagnosis was made according to the diagnostic criteria recommended by Rett Syndrome Diagnostic Criteria Work Group in 1988. Molecular analysis of MECP2 gene was done and compared with worldwide reports. RESULTS: Three of six RTT had mutations in TRD domain of exon 4 in MECP2 gene. Two of these mutations were nonsense mutaions which were previously reported by others, however, one case was a novel mutation with 44 bp deletion which causes frameshift and premature termination of translation at codon 409. Two single nucleotide polymorphism (SNP) was detected in the exon 1 and exon 4. Since the SNP in exon 1 has not been reported by others, it may be a Korean-specific SNP. Because of the size of cases in this study, the genotype-phenotype relationship could not be assessed. CONCLUSION: The results of this study shows the common types of point mutations as well as a novel type of deletion in MECP2 gene in RTT.

A Case of R122H Mutation of Cationic Trypsinogen Gene in a Pediatric Patient with Hereditary Pancreatitis Complicated by Pseudocyst and Hemosuccus Pancreaticus / 대한소화기학회지

Hereditary pancreatitis is a rare autosomal dominant inherited disease with 80% penetration rate. The disease is characterized by recurrent episodes of pancreatitis often beginning in childhood, positive family history with at least two other affected members and no known precipitating factors. Most forms of hereditary pancreatitis are caused by one of two commoner mutations, R122H in exon 3 and N29I in exon 2 of the cationic trypsinogen (CT) (PRSS1) gene, located on chromosome 7. These genetic defects are speculated to cause excessive trypsin activity or to prevent inactivation of prematurely activated trypsin, resulting in pancreatitis. We performed mutation analysis of a Korean family with two members having clinically suspicious hereditary pancreatitis. We analyzed the CT gene in DNA samples extracted from peripheral blood of five family members. First of all, polymerase chain reaction and restriction enzyme digestion were performed in exon 3 of the CT gene. And then DNA products were purified and sequenced. We found out that three members of the family, the mother and two daughters, had a R122H mutation of the CT gene. We report the first family of hereditary pancreatitis associated with the CT gene mutation, an arginine to histidine amino acid substitution at residue 122, in Korea.

Gender Differences in Alcohol Metabolizing Hepatic Enzyme Genotypes in Korean Patients with Alcohol Dependence / 신경정신의학

OBJECTIVES: There are a number of preceding epidemiological studies reporting gender differences in the genetic etiology of alcohol dependence. The author investigated gender difference in the frequencies of ADH2 and ALDH2 genoypes between the patients with alcohol dependence and normal control. METHODS: The subjects were 141 alcohol dependent patients (104 males, 37 females) and 138 normal control (79 males, 59 females). The frequencies of 1/1 and 1/2+2/2 (2+ afterward) genotypes for ADH2 and ALDH2 were investigated in male and female between alcohol dependence and normal control group. DNA was extracted from WBC in peripheral venous blood and PCR-RFLP method was used out for genotyping. RESULTS: First, the frequency of ADH2 1/1 genotype was significantly higher in alcohol dependent patients than normal control in both genders. Second, while there was no gender difference in the frequency of ADH2 1/1 genotype in normal controls, in the patient group however, the frequency was significantly higher in females than males. Third, in male subjects with alcohol dependence, the frequency of ALDH2 1/1 genotype was significantly higher than in male normal control subjects. On the other hand, in female subjects with alcohol dependence, the frequency of ALDH2 2+ genotype was significantly higher than in female normal control subjects. CONCLUSION: These results suggest that while the risk of alcohol dependence is predominantly affected by ALDH2 1/1 genotype in male, the female ADH2 1/1 genotype is mainly associated with the risk of alcohol dependence. This means that there are gender differences in the genetic etiology of alcohol dependence.

Isolation of Nontuberculous Mycobacteria by DNA Probe and Clinical Characteristics of Patients with NTM Pulmonary Disease / 결핵및호흡기질환

BACKGROUND: Nontuberculous mycobacterial (NTM) infections are increasingly being recognized as a cause of chronic pulmonary disease. This study describes the prevalence of NTM species from clinical specimens and the clinical characteristics of NTM pulmonary disease. MATERIAL AND METHODS: The NTM isolated from March 2003 to December 2003 at the Kosin Medical Center were identified using an oligonucleotide chip containing the internal transcribed space (ITS) sequence. The medical records of the patients with the NTM isolates, who fulfilled the 1997 ATS diagnostic criteria for NTM pulmonary disease, were analyzed, retrospectively. RESULTS: Twenty four species (24.2%) of NTM were isolated from 99 cultured AFB specimens. M. avium complex (MAC) (13 isolates), M. szulgai (3), M. kansasii (2), M. malmoense (2), M. abscessus (1), M. chelonae (1), M. scrofulaceum (1), and unclassified (1). Of the 23 patients with isolated NTM, 11 patients were found to be compatible with a NTM pulmonary infection according to the ATS criteria; MAC was found in 6 cases (54.5%), M. szulgai in 2 cases (18.2%), and M. abscessus, M. szulgai, M. kansasii and M. malmoense in 1 case each (9.1%). Ten patients (91%) were male and the median age at diagnosis was 61 years. In the pre-existing diseases, malignant disease was found in 6 cases including 5 patients with lung cancer, and history of old pulmonary tuberculosis was identified in 4 cases. The radiological patterns showed lung destruction lung in 3 cases, a cavitary mass in 3 cases, a nodular pattern in 2 cases, and reticulonodular, consolidation and a bronchiectasis pattern were in 1 case each. CONCLUSION: Various types of NTM pulmonary diseases were`found in a tertiary hospital at Busan, Korea. The NTM pulmonary diseases were caused by MAC, M. szugai, M. kansasii, M. malmoense, M. abscessus, M. chelonae, and M. scrofulaceum in the order of frequency.

Association between Clozapine-Induced Weight Gain and Serotonin 5-HT2C Receptor Gene Polymorphism in Patients with Schizophrenia / 대한정신약물학회지

OBJECTIVE: Weight gain is one of the troublesome adverse reaction to clozapine treatment. This problem can lead to poor adherence to treatment. Clozapine-induced weight gain may be associated with genetic predisposition. Recent studies have shown that a polymorphism of the promoter region of the serotonin 5-HT2C receptor gene is associated with antipsychotic-induced weight gain. This study is to investigate the association of clozapine-induced weight gain with -759C/T polymorphism of serotonin 5-HT2C receptor promoter gene in schizophrenic patients. METHODS: Fifty three patients with schizophrenia were included in this study. The subjects were divided into two groups according to body weight change between the start and 10 weeks of clozapine. The cutoff level of weight change is 5% increase of initial body weight. Genotypes of -759C/T polymorphism were identified from AciI-digested fragments of two-primer products amplified by polymerase chain reaction corresponding to -885 to -634 of the serotonin 5-HT2C receptor gene promoter region on chromosome X. RESULTS: There were no differences of baseline variables between patient groups with and without weight gain. 4 of 32 male patients and 6 of 21 female patients had -759T allele, respectively. The authors found that patients with -759T allele had tendency to show less weight gain than those without this allele. CONCLUSION: These findings suggest that clozapine- induced weight gain may be associated with genetic predisposition in schizophrenic patients.

Detection of YMDD Motif Mutants by Oligonucleotide Chips in Lamivudine-Untreated Patients with Chronic Hepatitis B Virus Infection

Lamivudine, a nucleoside analogue, has been used widely as an effective antiviral agent for the treatment of patients with chronic hepatitis B virus (HBV) infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine occurs very frequently after long term therapy. We developed an oligonucleotide chip for the detection of YMDD motif mutants resistant to lamivudine and investigated the prevalence of the mutants in patients with chronic HBV infection who had not been treated by lamivudine before. Forty patients who had not been treated with lamivudine were included in this study. Serum samples were tested by the oligonucleotide chips designed for detection of wild-type YMDD motif, M552V and M552I. Samples were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. M552I mutants were detected by the oligonucleotide chips in 7.5% (3/40) of chronic HBV infected patients (2 chronic hepatitis and 1 cirrhosis). The results were in accordance with those of RFLP. YMDD motif mutants occur as natural genome variabilities in patients with chronic HBV infection who had not been treated with lamivudine before. Oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of mutants resistant to antiviral therapy in chronic HBV infection.

The Change of Telomerase Activity by Cisplatin and 5-FU in Head and Neck Cancer Cell Lines / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Telomerase activity appears to be associated with cell immortalisation and malignant progres-sion. Telomerase activity has been found in the majority of human tumours, but not in most somatic cells or tissues. We studied the change in the telomerase activity by cisplatin and 5-fluorouracil (5-FU) in head and neck cancer cell lines. SUBJECTS AND METHODS: Three different human head and neck cancer cell lines (PNUH-12, SNU-899, HEp-2) were studied. Cell cytotoxi-city and change of telomerase activity by 5-FU and cisplatin treatment were assessed by MTT and TRAP assays. RESULTS: The telomerase activity was detected in the head and neck cancer cell lines. After the cisplatin treatment, the telomerase activity was decreased in a concentration-dependent manner. However, after 5-FU treatment, the telomerase activity showed a slight decrease or no change at the concentration similar to that of cisplatin in the inhibition of tumor growth. CONCLUSION: Our results can explain one of the reasons why cisplatin is more effective than 5-FU in the chemotherapy of head and neck cancer.

Direct Detection of Clostridium difficile Toxin B Gene by Nested PCR in Human Stool Specimens / 대한임상미생물학회지

BACKGROUND: Clostridium difficile is the major cause of antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC). The aim of this study was to develop the nested PCR assay for direct detection of toxigenic C. difficile in stool specimens and to evaluate the usefulness of the method. METHODS: Specificity of newly designed primers are tested with 36 reference strains of intestinal flora. Lower detection limit of nested PCR for B toxin gene in C. difficile was determined using 10-fold serial dilutions of C. difficile ATCC 9689. One hundred and two clinical stool samples were cultured for detection of C. difficile on cycloserine-cefoxitin- fructose agar and the PCR assay for detection of toxin B gene in C. difficile isolates was performed. Nested PCR assay for direct detection of toxin B gene in clinical samples was also performed. RESULTS: Nested PCR assay showed negative amplification results in intestinal floras except C. difficile ATCC 9689. Lower detection limit of nested PCR for toxin B gene was 10 4 CFU/mL. Sensitivity of nested PCR assay compared to culture method was 100% (29/29), and the specificity was 68% (50/73). CONCLUSION: Nested PCR assay showed high sensitivity in direct detection of toxin B gene in C. difficile isolates even after administration of metronidazole, so the assay could be used in initial diagnosis and follow-up tests of AAD and PMC.

Natural YMDD Motif Mutations of HBV Polymerase in the Chronic Hepatitis B Virus Infected Patients / 대한간학회지

BACKGROUND/AIMS: Lamivudine, a nucleoside analogue has been widely used as an effective antiviral agent for the treatment of patients with chronic hepatitis B infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine very frequently occurs after long-term use of lamivudine. It is well known that the mutation is selected by the lamivudine. We hypothesized that a few mutant strains of YMDD motif are present as quasispacies before the lamivudine treatment, are selected by the treatment, and breakthrough during treatment. We investigated the prevalence of the YMDD motif mutants in patients with chronic hepatitis B infection who had not been treated by antiviral agents before. METHODS: The study included the serums of 40 patients with chronic heptitis B infection, which stored at -70 degrees C. Thirty-four patients had chronic hepatitis and 6 patients had cirrhosis. Thirty-one patients were diagnosed by liver biopsy. The average age and range were 29 years and 13-57 years respectively. None had taken any antiviral agents before. To detect YMDD mutants, YVDD (M552V), and YIDD (M552I), we used direct sequencing and the restriction fragment length polymorphism (RFLP) method. RESULTS: The YMDD mutant was detected by RFLP method in 7.5% (3/40) of the patients with chronic hepatitis B infection, in two patients with chronic hepatitis and one with cirrhosis. All were YMDD+ YIDD mutants. CONCLUSIONS: The YMDD motif mutation occurs spontaneously without antiviral therapy in patients with chronic hepatitis B infection.

Association of Functional microOpioid Receptor Genotypes with Alcohol Dependence in Koreans / 신경정신의학

OBJECTIVES: Previous studies have shown that the endogenous opioid system, which plays an important role in drinking behavior, might be related to the genetic etiology of alcohol dependence. And a recent study reported that the affinity of micro opioid receptor, which is closely related to the endogenous opioid system activity, is affected by the genotype of micro opioid receptor gene (OPRM1) A118G. The present study examined the association of the genotype of OPRM1 A118G with alcohol dependence in Koreans. METHODS: The author studied the genotype of OPRM1 A118G in 112 Korean patients with alcohol dependence and 140 healthy Korean control subjects. RESULTS: 1) A statistically significant increase in A/G or G/G genotype of OPRM1 A118G was observed in patients with alcohol dependence (67.0%) compared to the controls (51.4%). 2) Among patients with alcohol dependence, no significant difference in OPRM1 A118G polymorphism was observed relative to the age at which drinking started, the age of onset of alcohol-related problems, the age of first admission to psychiatric hospital for alcohol-related problems, the family history of alcohol dependence in the first-degree relatives or of severe alcohol withdrawal symptoms. But the frequency of A/G or G/G genotypes of OPRM1 A118G was significantly higher in those who drank 17 days or more per month in the previous year (80.8%) than in those with fewer days of drinking (56.5%). CONCLUSION: These results suggest that A/G or G/G genotypes of micro opioid receptor gene A118G are important genetic factors in the etiology of alcohol dependence.