PURPOSE: Prostate-specific antigen(PSA) is believed to be the most useful tumor marker available for prostate cancer. Our intension was to establish the normal pattern of PSA changes with age and initial PSA to provide baseline data from which disease progression might be detected. MATERIALS AND METHODS: Patients, who received serum PSA screening test more than twice, between January 1997 and December 2005, at the health center of Asan Medical Center, were selected for this investigation. The PSA levels of 27,439 adult males, aged between 20 and 79 years, with no known prostate disease, were determined using the Tandem-R PSA assay (Hybritech). The PSA values were determined at the baseline and after 1 to 8 years. To estimate the increase in the level of serum PSA according to age, a one-way ANOVA test was carried out. Every change in an individual's PSA level was compiled to plot curves of the PSA according to the initial age and initial PSA. The PSA doubling times were also calculated with different PSA values at different ages. RESULTS: The mean PSA levels according to age steadily increased, and were directly correlated with age(p<0.001). These increases were greater for those in their fifties and most severe after their sixties. The future PSA and doubling time of an individual can be predicted based on his age and known history of PSA. CONCLUSIONS: The model indicates the expected rises in the PSA level in relation to age and the PSA doubling times in healthy Korean men. This will provide baseline data from which disease progression might be detected.
Adult ; Chungcheongnam-do ; Disease Progression ; Humans ; Korea ; Male ; Mass Screening ; Prostate ; Prostate-Specific Antigen* ; Prostatic Neoplasms

BACKGROUND: Hemoglobin A1c (HbA1c) is considered a marker useful for the follow-up and diagnosis of diabetes and implies the importance of reliable assay methods that are traceable to a reference method. We evaluated analytical performance of a new high-performance liquid chromatography system for the HbA1c assay: D-100 from Bio-Rad Laboratories (USA). METHODS: We evaluated precision, linearity, and carry-over of D-100, according to the Clinical and Laboratory Standards Institute's guidelines. Comparative analysis of D-100 with Integra 800 (Roche Diagnostics, Germany) and Capillarys 3 (Sebia, France) was conducted. Additionally, we evaluated the throughput of the three instruments. RESULTS: Precision of low- and high-concentration controls in D-100 showed a CV of less than 1%. The linearity was excellent (R²=0.999) in the range of 3.51-18.7%, and carry-over was not observed. HbA1c results of D-100 (n=144) showed good correlation with those of Integra 800 (r=0.993) and Capillarys 3 (r=0.996). The % bias between D-100 and Integra 800 or Capillarys 3 was within the allowable range at all 3 medical decision levels (5.7%, 6.5%, and 10.0%). Elapsed time in the analysis of the first sample by D-100 was shorter than that of Integra 800 (2.4 vs. 11.1 minutes), but subsequent samples took more time (0.8 vs. 0.3 minutes per sample). CONCLUSIONS: D-100 showed reliable analytical performance with good precision and linearity, minimal carry-over, and acceptable comparative characteristics relative to other instruments. D-100 is expected to be useful for clinical measurements of HbA1c for diabetes diagnosis and theranostics.
Bias (Epidemiology) ; Chromatography, Liquid ; Diagnosis ; Follow-Up Studies ; Methods ; Theranostic Nanomedicine

PURPOSE: To assess the impact of physical characteristics on the incidence of varicoceles. Although previous reports have alluded to the fact that taller individuals may have a higher incidence of varicoceles, this has not been systematically studied. We hypothesized that physical characteristics such as height and weight could have a significant impact on the incidence of varicoceles. MATERIALS AND METHODS: We retrospectively reviewed charts of 145 patients who presented for evaluation of varicocele between 2000~2005. Each patients' age, symptoms, height, weight and body mass index (BMI) were recorded. Independent t-tests were performed to determine whether a correlation existed between presence of a varicocele and height, weight, or BMI. Moreover, we selected 90 patients whose varicocele was detected by pain and performed the same analysis in order to exclude selection bias. Additionally, we compared varicocele grade with height, weight and BMI by one-way ANOVA test. RESULTS: Our analysis showed that there was no association between height and the presence of a varicocele. However, the weight of the patient and the incidence of varicocele approached significance with greater weight associated with a lower incidence of varicoceles. There was also an association between BMI and the presence of varicoceles but the correlation did not depended on varicocele grade. CONCLUSIONS: Although previous reports have alluded to a higher incidence of varicoceles in taller patients, the current study found no correlation between height and the presence of a varicocele. Increased weight, however, was associated with a significantly lower incidence of varicoceles. Varicocele grade was not correlated with any factor. This study demonstrates that height is not a consideration when evaluating the infertile male, whereas weight may affect the ability to diagnose the varicocele.
Body Height ; Body Mass Index ; Humans ; Incidence ; Male ; Retrospective Studies ; Selection Bias ; Varicocele*

Background: Blastocystis is a genus of intestinal, anaerobic protozoan parasites that can be isolated from humans, animals, and the environment. We aimed to determine the distribution of Blastocystis and subtypes (STs) using stool samples obtained from healthy volunteers at collection centers in South Korea. Methods: A total of 478 stool samples from volunteers were collected at five collection centers throughout South Korea. The presence of Blastocystis was determined using PCR based on the small subunit (SSU) rRNA gene, and Blastocystis STs were confirmed through sequencing of the SSU rRNA gene. Results: Molecular analysis revealed the presence of Blastocystis in 27 (5.6%) of the enrolled participants. Two STs were identified: ST3 (66.7%) and ST1 (33.3%). The positive rates of Blastocystis varied by geographical region, ranging from 1.2%–12.0%. ST3 was the predominant subtype in all centers except one, where only ST1 was isolated. Phylogenic analysis showed clustering based on ST, but no significant differences were found among the regions. There was no association between Blastocystis colonization and either age or sex of the participants. Conclusions The results of this multicenter study demonstrated colonization by Blastocystis, mainly ST3, in the gastrointestinal tracts of asymptomatic individuals in South Korea.

Background: There has been a marked increase in the mortality rate associated with Clostridioides difficile infection (CDI) globally since 2003, with the emergence of binary toxinproducing ribotype 027 strains. However, the molecular epidemiology of C. difficile shows regional differences and ribotype 027 is not common in Korea. In this study, the risk factors for severe CDI were evaluated, while considering the region-specific molecular epidemiology. Methods: A retrospective case-control study was performed. Cases (n = 149) included patients with severe CDI or severe complicated CDI. Controls (n = 155) consisted of patients with nonsevere CDI. Results: Advanced age (odds ratio [OR] = 1.017, P = 0.0358), a history of chemotherapy (OR = 2.695, P = 0.0464), and ribotype 002 (OR = 3.406, P = 0.0231) were statistically significant factors associated with severe CDI in a multivariate analysis. Conclusion Ribotype 002 was found to be a significant risk factor for severe CDI in this study.Therefore, the surveillance of C. difficile ribotypes is recommended to monitor the spread of high-risk clones.

Background: The incidence of community-associated (CA) Clostridioides difficile infection (CDI) has increased in Korea. In this study, we evaluated CA-CDI risk factors in terms of clinical features and ribotype considering its region-specific molecular epidemiology. Methods: A retrospective case-control study was performed on two groups of CDI patients:127 subjects with CA-CDI and 265 subjects with healthcare-associated (HA)-CDI. Risk factors for CA-CDI were evaluated in terms of clinical and microbiological features such as toxin type and ribotype. Results: A comparison of the two groups of CDI patients revealed that inflammatory bowel disease, diarrhea, abdominal pain, and fever were more closely associated with CA-CDI. The toxin types and ribotypes of C. difficile were similar between the two groups. After adjusting for variables, no risk factors were identified for CA-CDI compared with HA-CDI. Conclusion Specific risk factors for CA-CDI were not identified in this study.

Background: Intestinal protozoa are potential diarrhea-causing pathogens and monitored worldwide. The Korea Centers for Disease Control and Prevention has also been monitoring intestinal protozoa causing diarrhea for many years. Recently, the overall protozoa detection rate has decreased to less than 1%, but whether protozoa infection causing diarrhea has declined or is being underestimated has not been studied. This study aimed to investigate the molecular epidemiology of intestinal protozoan pathogens in stool samples collected from multiple Korean centers. Methods: Stool samples were collected from five university hospitals and a commercial laboratory. Direct smear and trichrome staining were performed on all samples. The presence of Cryptosporidium parvum, Giardia lamblia, Entamoeba histolytica, Cyclospora cayetanensis, Dientamoeba fragilis, and Blastocystis hominis were detected using Allplex™ Gastrointestinal Parasite Assays (Seegene Inc., Korea). Microsporidia species and Kudoa septempunctata were detected using PowerChek™ Microsporidia Multiplex and Kudoa Real-time PCR kits (Kogene Biotech, Korea), respectively. Results: The collected samples included 279 diarrheal and 51 non-diarrheal samples. Among the 279 diarrheal samples, nine samples [B. hominis (n=7), C. parvum (n=1), and Microporidia species (n=1)] were positive, but there were no positive samples for K. septempunctata. We could not detect any protozoa by direct smear and trichrome staining. Among the 51 nondiarrheal samples, 10 (19.6%) samples were positive for B. hominis, but no other protozoa were observed Conclusion This multicenter study showed that the detection rate of intestinal protozoa is currently low in diarrheal samples from Korea. However, B. hominis was frequently detected in non-diarrheal samples, indicating their low pathogenicity.

Methods: A total of 889 non-duplicated clinical isolates were included in this study. The results of ASTA MicroIDSys were compared with those of Bruker Biotyper; 16S rRNA sequencing was performed for the species for which results obtained using the two systems did not match. The sequences of rpoB, hisA, and/or recA for the clinical isolates of Acinetobacter species, Klebsiella species, and Burkholderia cepacia complex were analyzed and used as reference identifications. Results: The concordance rates for bacterial identification using ASTA MicroIDSys and Bruker Biotyper were 100% at the genus level and 98.3% at the species level for isolates belonging to the order Enterobacterales. Similarly, the concordance rates at the genus and species levels were 98.8% and 91.0% for glucose non-fermenting bacilli, 100% and 100% for gram-positive cocci, and 98.9% and 98.9% for other isolates, respectively. ASTA MicroIDSys was expected to correctly identify 97.9% of the 108,251 isolates identified in our clinical microbiology laboratory over the past 5 years. Conclusion ASTA MicroIDSys showed excellent performance in bacterial identification for most of the clinically relevant species. Further extension of the database could improve the identification accuracy of ASTA MicroIDSys.

No abstract available.
Herbaspirillum ; Pneumonia ; Sepsis