Performance evaluation of the HepB Typer-Entecavir kit for detection of entecavir resistance mutations in chronic hepatitis B

BACKGROUND/AIMS: Molecular diagnostic methods have enabled the rapid diagnosis of drug-resistant mutations in hepatitis B virus (HBV) and have reduced both unnecessary therapeutic interventions and medical costs. In this study we evaluated the analytical and clinical performances of the HepB Typer-Entecavir kit (GeneMatrix, Korea) in detecting entecavir-resistance-associated mutations. METHODS: The HepB Typer-Entecavir kit was evaluated for its limit of detection, interference, cross-reactivity, and precision using HBV reference standards made by diluting high-titer viral stocks in HBV-negative human serum. The performance of the HepB Typer-Entecavir kit for detecting mutations related to entecavir resistance was compared with direct sequencing for 396 clinical samples from 108 patients. RESULTS: Using the reference standards, the detection limit of the HepB Typer-Entecavir kit was found to be as low as 500 copies/mL. No cross-reactivity was observed, and elevated levels of various interfering substances did not adversely affect its analytical performance. The precision test conducted by repetitive analysis of 2,400 replicates with reference standards at various concentrations showed 99.9% agreement (2398/2400). The overall concordance rate between the HepB Typer-Entecavir kit and direct sequencing assays in 396 clinical samples was 99.5%. CONCLUSIONS: The HepB Typer-Entecavir kit showed high reliability and precision, and comparable sensitivity and specificity for detecting mutant virus populations in reference and clinical samples in comparison with direct sequencing. Therefore, this assay would be clinically useful in the diagnosis of entecavir-resistance-associated mutations in chronic hepatitis B.

Clinical Effectiveness of Restriction Fragment Mass Polymorphism Assay for Human Papillomavirus Genotyping / 임상검사와정도관리

BACKGROUND: Human papillomavirus (HPV) infection is the main cause of cervical cancer and with the advent of genotype specific vaccines, there is increased need for accurate, broad-spectrum and high-throughput methods for HPV genotyping. A MALDI-TOF mass spectrometry (MS)-based restriction fragment mass polymorphism (RFMP) assay has proven to accurately and reliably genotype a wide variety of HPV. METHODS: We evaluated the clinical utility of the RFMP assay in HPV genotyping by testing a total of 2,689 specimens taken from liquid-based cytology, which was composed of normal cytology, atypical squamous cells of undetermined significance (ASCUS), low grade squamous intraepithelial lesion (LSIL), high grade squamous intraepithelial lesion (HSIL) and invasive squamous cervical cancer (SCC). RESULTS: Overall HPV positive rate of total specimens was 32.5% and the high-risk positivity was 16.4%. The HPV positive rates were increased as increasing severity level of cervical lesion. Predominant high-risk HPV genotypes were found as following order; 52 (18.6%), 16 (13.7%), 18 (3.8%), 58 (3.4%), 56 (2.6%) and 31 (2.5%). The high-risk HPV positivities according to cytologic diagnosis were 10.7% (238/2229), 31.7% (76/240), 50.0% (88/176), 86.0% (37/43), 100% (1/1) in normal, ASCUS, LSIL, HSIL and SCC subgroups, respectively. The concordance rate and Kappa value between sequencing and RFMP assays were 96.6% and 0.932 (95%CI: 0.908-0.956). CONCLUSIONS: The RFMP HPV genotyping assays showed high concordance with sequencing. The assay is simple, and can accurately detect and identify HPV genotypes in samples with various levels of cytological lesions. The results demonstrated that RFMP assay should be clinically suitable for HPV genotyping in laboratories.

Relationship between Internet Addiction and Anxiety, Depression, and Self Efficacy in Middle and High School Students / 신경정신의학

OBJECTIVES: Internet addiction is a newly appeared addiction phenomenon that is defined as 'difficulty in real life due to internet over-use', 'excessive time spent on the internet or replacement of genuine real relationships with superficial virtual ones' or 'weakness in self-control about internet use and if withdrawn, fallen in psychological confusion and anergic state'. The aims of this study were to estimate the prevalence of the internet addiction in Korean middle and high school students who are known to suffering from severe academic loading compared to foreign students, and to compare the demographic factors, internet-using patterns, anxiety trait, depression and internet self-efficacy and outcome expectancy between addicted group and non-addicted group. METHODS: Subjects were middle and high school students in Seoul and Cheonan city (N=1173). Self-rating questionnaire included demographic data, Korean version of Spielberger State-Trait Anxiety Inventory, Self-Rating Depression Scale(SDS), and questions for internetusing pattern, Young internet addiction scale, internet self-efficacy and outcome expectancy scale. We have received the consent form teachers and students. RESULTS: In this study, prevalence of internet addiction is 2.9%. Addicted group showed higher level of anxiety, depression, and self-efficacy acquired from internet use than those of non-addicted group. Addicted group spent much more leisure time alone, used more high-speed internet service, and thought negatively about influence of internet to real life than non-addicted group. Addicted group had higher rate of insight for internet addiction than non-addicted group. CONCLUSION: This study suggest that prevalence of internet addiction is much lower than expected, but internet addiction can worse the anxious and depressive tendency. Also this study show that internet overusing and subsequent internet addiction can have negative influences on the real life.