Yong-Wha Lee

The effects of green tea ingestion over four weeks on atherosclerotic markers

Background: The objective of this study was to evaluate the effects of green tea ingestion over four weeks on atherosclerotic biological markers. Methods: After a one-week baseline period, 12 healthy male volunteers aged 28-42 years drank 600 mL of green tea dailyfor four weeks. Lipid profile, oxidized low-density lipoprotein (ox-LDL), total antioxidant capacity (TAC), C-reactive protein (CRP) and soluble cell adhesion molecules were measured at baseline and after two and four weeks ingestion of green tea. Results: There was no significantchange in the concentrations of lipid profile, TAC, CRP, soluble intercellular adhesion molecule-1 (sICAM-1), or soluble E-selectin after ingestion of green tea. The levels of ox-LDL and soluble vascular cell adhesion molecule-1 (sVCAM-1) were significantly decreased after four weeks of green tea ingestion (Wilcoxon signed rank test, P=0.006). Conclusions: The results of this study suggest an in vivo anti-oxidative effect for green tea and an influence of green tea on atherosclerotic biological markers. The effect of green tea seen on ox-LDL and sVCAM-1provides a potential mechanism for the cardiovascular benefits of regular ingestion of green tea.

Molecular screening of the TSH receptor (TSHR) and thyroid peroxidase (TPO) genes in Korean patients with nonsyndromic congenital hypothyroidism

Objective  To investigate thyroid‐stimulating hormone receptor (TSHR) and thyroid peroxidase (TPO) mutations in Korean patients with primary congenital hypothyroidism (CH).

Simultaneous Screening of 177 Drugs of Abuse in Urine Using Ultra-performance Liquid Chromatography with Tandem Mass Spectrometry in Drug-intoxicated Patients

Objective The demand for rapid and broad clinical toxicology screening methods to identify drugs of abuse and medicinal drugs is increasing steadily. Liquid chromatography-tandem mass spectrometry (LC-TMS) is increasingly used to screen for drugs of abuse and to identify a wide range of drugs and metabolites in clinical samples. We revised a high-throughput and rapid ultra-performance (UP) LC-TMS method for simultaneous screening of 177 of the most prevalent medicinal drugs and drugs of abuse in urine and validated the quality of performance using system suitability mixture (SSM) and quality control (QC) materials. Methods We assessed the limits of detection (LOD) using high concentrations of the test substances. The method was applied to 473 urine samples obtained from patients intoxicated with drugs who visited the emergency center. Results The retention time, peak area, and total ion chromatogram of the SSM and QC materials were within the acceptance criteria of the pre-defined acceptance interval. The LODs were <62 ng/ml for 12 commonly encountered drugs. In total, 418 patients (88.4%) tested positive for one or more medicinal drugs or drugs of abuse. Twenty-eight drugs were detected over ten times; the most commonly detected were zolpidem, ephedrine, paracetamol, and chlorpheniramine. Conclusion The UPLC-TMS method provided excellent performance for simultaneous screening of a large number of the drugs of abuse in urine samples. We conclude that this robust technique is useful for screening for a large number of drugs and for rapid screening of the most commonly encountered substances in emergency cases.

Molecular genetics of citrullinemia types I and II.

Over the past decade, the ASS1 and SLC25A13 genes, which are responsible for citrullinemia types I and II, have been identified, and numerous mutations in these genes have been reported. The clinical manifestations of citrullinemia are quite heterogeneous, and most studies have reported mutations in a small number of patients from a few families. Comprehensive integration of previous knowledge is important to understand the mutation spectrum and effect of the mutations on clinical manifestations. Therefore, we reviewed the English literature on mutations in the ASS and SLC25A13 genes, and their genotype-phenotype correlations to provide valuable insights into the molecular genetic background of citrullinemia types I and II.

Comparison between ultra‑performance liquid chromatography with tandem mass spectrometry and a chemiluminescence immunoassay in the determination of cyclosporin A and tacrolimus levels in whole blood

Regular immunosuppressant drug monitoring is important for maintaining the drug concentrations of organ recipients within the therapeutic range. The standardized liquid chromatography-tandem mass spectrometry (LC-TMS) technique has been used for the accurate analysis of immunosuppressive drugs. In the present study, the performance of the recently developed high-throughput, rapid ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-TMS) method was validated for the simultaneous measurement of cyclosporin A and tacrolimus in whole blood. The method of measuring cyclosporin A and tacrolimus using UPLC-TMS was established and the precision, limit of detection (LOD), limit of quantitation (LOQ) and matrix effect were validated. In addition, the performance of UPLC-TMS was compared with that of a chemiluminescence immunoassay (CLIA) in >3,400 clinical specimens. The UPLC-TMS revealed a within-run and between-run precision of <8% and showed a bias of <5%. The LOD and LOQ were 2.0 and 2.5 ng/ml for cyclosporin A, and 0.3 and 0.4 ng/ml for tacrolimus, respectively. Interference from the matrix was not observed. The CLIA measurements of cyclosporin A and tacrolimus showed correlations corresponding with the formulae: Concentration(CLIA) = 1.18 × UPLC-TMS – 5.85; [95% CI: proportional, 1.16–1.19; constant, −6.86–(−4.81)] and Concentration(CLIA) = 1.14 × UPLC-TMS – 0.38; [(95% CI: proportional, 1.13–1.14; constant, −0.35–(−0.43)], respectively. The majority of results were higher for the immunoassay than for the UPLC-TMS. The newly developed rapid UPLC-TMS method was suitable for use with a large therapeutic concentration range of the analyzed immunosuppressive drugs. Sample preparation was simple and it was possible to detect several immunosuppressants simultaneously, thus significantly lowering the cost of analysis. In conclusion, this method may contribute to improved accuracy and may be preferred to immunoassays for the routine clinical measurement of immunosuppressive drug concentrations in whole blood.

Identification of a Novel Splicing Mutation in the ARSA Gene in a Patient with Late-infantile Form of Metachromatic Leukodystrophy

Metachromatic leukodystrophy (MLD; MIM 250100), a severe neurodegenerative disorder inherited as an autosomal recessive trait, is caused by mutations in the arylsulfatase A (ARSA) gene. Although several germ line ARSA mutations have been identified in patients with MLD of various ethnic backgrounds elsewhere in the world, no genetically confirmed cases of MLD have been reported in Korea. Recently, we identified a mutation in the ARSA gene of a Korean male with MLD. A male infant with late-infantile form of MLD had been admitted to our hospital for further examination. His neuromuscular symptoms, which included inability to walk at the age of 12 months, gradually worsened, even after allograft bone marrow transplantation; he died at the age of 9 yr. His elder brother had also been diagnosed with MLD. To confirm the presence of a genetic abnormality, all the coding exons of the ARSA gene and the flanking introns were amplified by PCR. A molecular analysis of the ARSA gene revealed both a novel heterozygous splicing mutation (c.1101+1G>T) in intron 6 and a heterozygous missense mutation in exon 2 (c.296G>A; Gly99Asp). The patients elder brother who had MLD is believed to have had the same mutation, which may be correlated with a rapidly deteriorating clinical course. This study identified a novel mutation in the ARSA gene, related to a late-infantile form of MLD with a lethal clinical course and suggested that molecular diagnosis of patients may be useful in early diagnosis and for deciding intervention measures for their family members.

Discrepancy of interleukin-6 levels between end-stage renal disease patients and patients with acute-phase response with increased lipoprotein(a) concentrations.

Though the concentration of serum lipoprotein(a) [Lp(a)] is mostly determined by genetic factors, secondary factors such as acute‐phase response (APR) and end‐stage renal disease (ESRD) also contribute to its increase. Lp(a) is known to be one of the acute‐phase reactants and interleukin‐6 (IL‐6) is the key cytokine in the hepatic synthesis of acute‐phase proteins. The serum concentrations of Lp(a) and IL‐6 were measured in patients with APR and in patients with ESRD to investigate the relationship between Lp(a) and IL‐6. A total of 180 patients were selected for the study: 60 patients were normal controls, 60 were patients with renal disease who had been on hemodialysis for more than 6 months [C‐reactive protein (CRP)<4.0 mg/L], and 60 were APR patients who had a erythrocyte sedimentation rate (ESR) of over 50 mm/h. The three groups were age‐ and sex matched. The serum concentrations of Lp(a) and IL‐6 were measured by ELISA. The serum concentrations of Lp(a) [median (interquartile range)] in normal controls, ESRD patients, and APR patients were 0.222 (0.103–0.364) g/L, 0.511 (0.308–0.755) g/L, and 0.546 (0.234–0.747) g/L, respectively; those of IL‐6 were 1.0 (0.7–1.3) pg/mL, 2.1 (1.4–3.3) pg/mL, and 26.2 (15.2–35.6) pg/mL. The concentration of IL‐6, which increases Lp(a) synthesis, was much lower in ESRD patients than in APR patients (p<0.001). However, there were no significant differences in Lp(a) concentration between the two groups (p=0.88). In APR patients, the increase in Lp(a) synthesis seems to play a significant role in the increase in blood Lp(a), but there might be different mechanisms that regulate the increment of serum Lp(a) concentrations in ESRD patients other than synthesis of Lp(a).

The Association between Intraocular Pressure and Predictors of Coronary Heart Disease Risk in Koreans

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.

Peptide nucleic acid clamp polymerase chain reaction reveals a deletion mutation of the BRAF gene in papillary thyroid carcinoma: A case report

The BRAF point mutation is the most common genetic event in papillary thyroid carcinoma (PTC), occurring in 29–69% of such tumors. The V600E mutation accounts for up to 95% of all BRAF mutations. Therefore, the majority of diagnostic assays have been developed to detect only the V600E mutation of the BRAF gene. A peptide nucleic-acid (PNA)-clamp quantitative polymerase chain reaction (qPCR) was developed to detect the V600E mutation and other mutations in the BRAF gene. In this study, a 3-bp deletion mutation (c.1799_ 1801delTGA) was detected in a subject with a PTC by PNA clamp qPCR, in contrast with the results of allele-specific (AS)-PCR. The mutant allele was not detected by AS-PCR, but was detected using PNA-clamp PCR. The atypical 3-bp deletion mutation (c.1799_1801delTGA) was identified by confirmatory PCR combined with sequencing. The conversion of codons 600 (GTG) and 601 (AAA) into a single codon (GAA) resulted in the insertion of a glutamic acid residue into the activation segment of the B-raf protein (p.V600_K601delinsE). In cases where PTC is highly suspected but no mutation is detected by AS-PCR specific for V600E, PNA clamp qPCR, which is complementary to other sequencing methods, should be performed in order to detect other mutations in the BRAF gene.

Clinical and genetic analysis in a patient with primary renal glucosuria: Identification of a novel mutation in the SLC5A2 gene

Primary renal glucosuria (PRG; OMIM #233100) is characterized by persistent glucosuria due to a reduction in the renal tubular reabsorption of glucose in the presence of a normal concentration of serum glucose and the absence of any other impairment of tubular function. The SLC5A2 gene is the causative gene, which codes for the low-affinity sodium/glucose co-transporter SGLT2. In the present study, the case of a patient with PRG associated with a novel mutation of the SLC5A2 gene is reported. The patient visited hospital for the evaluation of glucosuria in the absence of hyperglycemia, a condition that had been present for >20 years. The patient showed a fasting blood sugar level of 104 mg/dl, a 2-h postprandial sugar level of 101 mg/dl, a sodium level of 144 mmol/l, a potassium level of 3.7 mmol/l and a chloride level of 106 mmol/l in serum. Urine chemistry revealed that the amount of glucose excreted was 10.8 g/1.73 m2/24 h; however, the levels of the other parameters were unremarkable. Polymerase chain reaction (PCR) sequencing analysis of the SLC5A2 gene from the patient revealed a novel 1 bp deletion mutation, which altered the coding sequence of exon 10 in the transmembrane domain (c.1162delG; Ala388ProfsX48), suggesting an autosomal dominant inheritance pattern. This study identified a novel mutation in the SLC5A2 gene related to a benign clinical characteristic and suggests that the molecular diagnosis of the SLC5A2 gene may be useful for diagnosing renal glucosuria in patients and for deciding intervention measures for their family members.