Cotinine has been widely used as an objective marker to identify current smokers. We conducted this study to address the absence of Korean studies investigating the efficacy of immunoassays and liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the detection of serum cotinine and to determine the optimal serum cotinine cut-off level for differentiating current smokers from nonsmokers.
Serum specimens were obtained from 120 subjects. They were randomly chosen to represent a broad distribution of urine cotinine levels based on a retrospective review of questionnaires and results of urine cotinine levels. We determined serum cotinine levels using the IMMULITE 2000 XPi Immunoassay System (Siemens Healthcare Diagnostics Inc., USA) and LC-MS/MS (API-4000, Applied Biosystems, USA). Correlation was analyzed between IMMULITE serum cotinine, urine cotinine, and LC-MS/MS serum cotinine levels. ROC curve was analyzed to identify the optimal IMMULITE serum cotinine cut-off level for differentiating current smokers from nonsmokers.
IMMULITE serum cotinine levels correlated with both urine cotinine and LC-MS/MS serum cotinine levels, with correlation coefficients of 0.958 and 0.986, respectively. The optimal serum cotinine cut-off level for distinguishing current smokers from nonsmokers was 13.2 ng/mL (95.7% sensitivity, 94.1% specificity) using IMMULITE.
This is the first study to investigate the use of LC-MS/MS for the measurement of serum cotinine and to determine the optimal serum cotinine cut-off level for the IMMULITE immunoassay. Our results could provide guidelines for differentiating current smokers from nonsmokers in the Korean population.
Cotinine; Cut-off; Korean; LC-MS/MS; Serum
To prevent the transmission of pathogens by endoscopes, following established reprocessing guidelines is critical. An ideal reprocessing step is simple, fast, and inexpensive. Here, we evaluated and compared the efficacy and safety of two disinfectants, a tertiary amine compound (TAC) and ortho-phthalaldehyde (OPA).
A total of 100 colonoscopes were randomly reprocessed using two same automated endoscope reprocessors, according to disinfectant. The exposure time was 10 minutes for 0.55% OPA (Cidex® OPA, Johnson & Johnson) and 5 minutes for 4% TAC (Sencron2®, Bab Gencel Pharma & Chemical Ind. Co.). Three culture samples were obtained from each colonoscope after reprocessing.
A total of nine samples were positive among the 300 culture samples. The positive culture rate was not statistically different between the two groups (4% for OPA and 2% for TAC, P=0.501). There were no incidents related to safety during the study period.
TAC was non-inferior in terms of reprocessing efficacy to OPA and was safe to use. Therefore, TAC seems to be a good alternative disinfectant with a relatively short exposure time and is also less expensive than OPA.
Colonoscopes; Cost; Disinfectants; Endoscopes
The association between serum bilirubin levels and incident chronic kidney disease (CKD) in the general population is unknown. We aimed to examine the association between serum bilirubin concentration (total, direct, and indirect) and the risk of incident CKD.
Methods and Findings
Longitudinal cohort study of 12,823 Korean male workers 30 to 59 years old without CKD or proteinuria at baseline participating in medical health checkup program in a large worksite. Study participants were followed for incident CKD from 2002 through 2011. Estimated glomerular filtration rate (eGFR) was estimated by using the CKD-EPI equation. CKD was defined as eGFR <60 mL/min per 1.73 m2. Parametric Cox models and pooled logistic regression models were used to estimate adjusted hazard ratios for incident CKD. We observed 238 incident cases of CKD during 70,515.8 person-years of follow-up. In age-adjusted models, the hazard ratios for CKD comparing quartiles 2–4 vs. quartile 1 of serum direct bilirubin were 0.93 (95% CI 0.67–1.28), 0.88 (0.60–1.27) and 0.60 (0.42–0.88), respectively. In multivariable models, the adjusted hazard ratio for CKD comparing the highest to the lowest quartile of serum direct bilirubin levels was 0.60 (95% CI 0.41–0.87; P trend = 0.01). Neither serum total nor indirect bilirubin levels were significantly associated with the incidence of CKD.
Higher serum direct bilirubin levels were significantly associated with a lower risk of developing CKD, even adjusting for a variety of cardiometabolic parameters. Further research is needed to elucidate the mechanisms underlying this association and to establish the role of serum direct bilirubin as a marker for CKD risk.
Microangiopathic hemolytic anemia (MAHA) occurs occasionally as a paraneoplastic syndrome in some solid tumors, but MAHA accompanied by signet ring cell carcinoma of an unknown origin is very rare. In this study, we present the case of an 80-yr-old man who was admitted to the hospital because of a 1-month history of lower back pain and dyspnea. He was diagnosed with MAHA on the basis of the laboratory findings that revealed anemia with schistocytes, decreased haptoglobin levels, and a negative direct Coombs' test. Bone marrow examination, which was performed because of the progression of anemia, revealed bone marrow metastases of signet ring cell carcinoma with extensive bone marrow necrosis. However, the primary origin of this signet ring cell carcinoma was not found. When the cause of progressive MAHA is unknown, the possibility of cancer-associated MAHA must be excluded by performing additional tumor workup, including the detection of tumor markers, gastric and colorectal endoscopic examinations, bone marrow examinations, and positron emission tomography-computed tomography or bone scans.
Bone marrow metastasis; Microangiopathic hemolytic anemia; Signet ring cell carcinoma
Pure red cell aplasia is characterized as a normocytic anemia associated with reticulocytopenia and the absence of erythroblasts in the bone marrow. Pure red cell aplasia can be induced by various causes such as thymoma, connective tissue disease, viral infection, lymphoma, and adverse drug reactions. There have been only a few reports of pure red cell aplasia associated with acute viral hepatitis A. In Korea, no case of pure red cell aplasia caused by acute hepatitis A has yet been reported. We recently experienced a case of acute viral hepatitis A complicated by pure red cell aplasia. The patient was successfully treated with corticosteroids. Here we report this case and review the literature.
Red-cell aplasia; Hepatitis A; Acute Kidney injury
Elevated intraocular pressure (IOP) is one of the major risk factors for glaucomatous visual field defects. Each individual systemic risk factor of coronary heart disease (CHD) is associated with elevated IOP, although no reports have argued for a correlation between the risk factors for CHD and IOP after a comprehensive or collective analysis. The National Cholesterol Education Program Adult Treatment Panel III presented the Framingham projection, which can predict the risk of CHD quantitatively. We investigated the association between IOP and the Framingham projection in 16,383 Korean subjects. The Framingham projection was applied using the indicated risk factors. The associations between the Framingham projection and IOP and the influences of the risk factors on the IOP were examined. The Framingham projection was correlated with the mean IOP in women (p<0.05). The relationship between IOP and systemic variables other than smoking was significant (p<0.05). The mean IOP was significantly higher in the high-risk CHD group than in the low-risk group based on the Framingham projection (p<0.05). Because an elevated IOP was associated with cardiovascular risk factors, subjects with a high CHD risk based on the Framingham projection need continuous monitoring for IOP to prevent glaucomatous visual field defects.
Coronary Disease; Intraocular Pressure; Koreans; Cholesterol; Low-Density Lipoprotein
The aims of this study were to estimate the incidences of BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions in childhood acute lymphoblastic leukemia (ALL), to identify new abnormalities, and to demonstrate the usefulness of interphase fluorescence in situ hybridization (FISH). We performed G-banding analysis and FISH using probes for BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions on 65 childhood ALL patients diagnosed and uniformly treated at a single hospital. Gene rearrangements were identified in 73.8% of the patients using the combination of G-banding and FISH, while the chromosomal abnormalities were identified in 49.2% using G-banding alone. Gene rearrangements were disclosed by FISH in 24 (72.7%) of 33 patients with normal karyotype or no mitotic cell in G-banding. Among the gene rearrangements detected by FISH, the most common gene rearrangement was p16 deletion (20.3%) and the incidences of others were 14.1% for TEL/AML1, 11.3% for MLL, and 1.8% for BCR/ABL translocations. Infrequent or new aberrations such as AML1 amplification, MLL deletion, ABL deletion, and TEL/AML1 fusion with AML1 deletion were also observed. We established the rough incidences of gene rearrangements in childhood ALL, found new abnormalities and demonstrated the diagnostic capability of interphase FISH to identify cryptic chromosome aberrations.
In Situ Hybridization, Fluorescence; Leukemia, Lymphocytic, Acute; Childhood; Gene Rearrangements
The identification of marker chromosomes is important for genetic counseling. However, the origin or composition can rarely be defined with conventional cytogenetic technique alone. In this study, we investigated the incidences and types of marker chromosomes in Korean patients and attempted to establish a cost-effective diagnostic approach for marker chromosomes. We reviewed the karyotypes of 2,984 patients that were requested for the cytogenetic analysis between 1997 and 2003 at the Samsung Medical Center. Ten marker chromosomes were found and identified using fluorescent in situ hybridization (FISH). Among the ten marker chromosomes, six were supernumerary marker chromosomes (SMCs) and the rest were marker chromosomes in Turner syndrome (TS). The incidence of SMCs was 2.01/1,000, slightly higher than that previously reported. Five of six SMCs were satellited marker chromosomes. Three bisatellited marker chromosomes originated from chromosome 15 and two from chromosome 22. The origin of one SMC could not be identified. All marker chromosomes in TS originated from X- or Y chromosome. The application of FISH is indispensable to identify marker chromosomes, and the appropriate selection of probes is necessary for cost-effective analysis. For analyzing satellited marker chromosomes, application of probes for chromosome 15 followed by those for chromosome 22 is recommended and in cases of TS, probes for sex chromosomes should take precedence.