No abstract available.

OBJECTIVE: Among various methods developed to quantitatively explore electroencephalograms (EEG), we focused on a wavelet method that was known to yield robust results under nonstationary conditions. The aim of this study was thus to introduce the wavelet method and demonstrate its potential use in clinical sleep studies. METHOD: This study involved artificial EEG specifically designed to validate the wavelet method. The method was performed to obtain time-dependent spectral power and phase angles of the signal. Synchrony of multichannel EEG was analyzed by an order parameter of the instantaneous phase. The standard methods, such as Fourier transformation and coherence, were also performed and compared with the wavelet method. The method was further validated with clinical EEG and ERP samples available as pilot studies at academic sleep centers. RESULT: The time-frequency plot and phase synchrony level obtained by the wavelet method clearly showed dynamic changes in the EEG waveforms artificially fabricated. When applied to clinical samples, the method successfully detected changes in spectral power across the sleep onset period and identified differences between the target and background ERP. CONCLUSION: Our results suggest that the wavelet method could be an alternative and/or complementary tool to the conventional Fourier method in quantifying and identifying EEG and ERP biomarkers robustly, especially when the signals were nonstationary in a short time scale (1-100 seconds).
Biomarkers ; Electroencephalography ; Fourier Analysis ; Pilot Projects

Sleep is an essential process maintaining the life cycle of the human. In parallel with physiological, cognitive, subjective, and behavioral changes that take place during the sleep, there are remarkable changes in the electroencephalogram (EEG) that reflect the underlying electro-physiological activity of the brain. However, analyzing EEG and relating the results to clinical observations is often very hard due to the complexity and a huge data amount. In this article, I introduce several linear and non-linear tools, developed to analyze a huge time series data in many scientific researches, and apply them to EEG to characterize various sleep states. In particular, the spectral analysis, detrended fluctuation analysis (DFA), and synchrony analysis are administered to EEG recorded during nocturnal polysomnography (NPSG) processes and daytime multiple sleep latency tests (MSLT). I report that 1) sleep stages could be differentiated by the spectral analysis and the DFA; 2) the gradual transition from Wake to Sleep during the sleep onset could be illustrated by the spectral analysis and the DFA; 3) electrophysiological properties of narcolepsy could be characterized by the DFA; 4) hypnic jerks (sleep starts) could be quantified by the synchrony analysis.
Brain ; Electroencephalography ; Humans ; Hypogonadism ; Life Cycle Stages ; Mitochondrial Diseases ; Narcolepsy ; Ophthalmoplegia ; Polysomnography ; Sleep Stages

No abstract available.
Genetics* ; Hyperaldosteronism*

No Abstract Available.
Retinal Detachment* ; Retinal Perforations* ; Retinaldehyde*

No abstract available.
Ischemia* ; Lower Extremity*

BACKGROUND: Therapeutic drug monitoring (TDM) has been shown to be effective in minimizing the risk for toxicity and maximizing the efficacy of the drugs. The application of pharmacokinetics principles to indiviualization and optimization of dosage is necessary. We evolved interpretative report system of digoxin determination in a view of individual's pharmacokinetics. The alto of the present study is to validate the effectiveness of the interpretative report system in digoxin therapeutic monitoring service. METHODS: We reviewed 125 inpatients of two groups. 4 group, before interpretative reporting, had 86 inpatients from February 1996 to March 1996. B group included 39 inpatients from September 1996 to October 1996 after the practice of the sytem. Digoxin concentrations were measured in serum by TDxFlex (Abbott Laboratories, U.S.A.). Each patient's digoxin pharmacokinetics was determined by using the Abbott-base Pharmacokinetics system (Abbott Laboratories, U.S.A.) . The interpretation for the assayed digoxin level, the recommendation of maintenance dosage and the simulation graph with predicted serum levels were included in the report. The effectiveness of the reporting system was evaluated by comparing the appropriateness of digoxin level measurement between both groups. RESULTS: It revealed that appropriate measurements of digoxin level were 59.5 % of the tests in A group and 77.1% of those in B group (p=0.006). Evaluation of serum digoxin concentrations stratified by digoxin concentration showed also significant difference among the percentage of tests in each concentration range between both groups (p=0.011). CONCLUSIONS: Interpretative report system for the assayed results caused to increase in the appropriateness of digoxin measurement. The report system with some improvement which is achieved through the active approach to physician helps us use TDM effectively. The system can be applied to the other TDM drugs.
Digoxin ; Drug Monitoring* ; Humans ; Inpatients ; Pharmacokinetics

BACKGROUND: Therapeutic drug monitoring (TDM) has been shown to be effective in minimizing the risk for toxicity and maximizing the efficacy of the drugs. The application of pharmacokinetics principles to indiviualization and optimization of dosage is necessary. We evolved interpretative report system of digoxin determination in a view of individual's pharmacokinetics. The alto of the present study is to validate the effectiveness of the interpretative report system in digoxin therapeutic monitoring service. METHODS: We reviewed 125 inpatients of two groups. 4 group, before interpretative reporting, had 86 inpatients from February 1996 to March 1996. B group included 39 inpatients from September 1996 to October 1996 after the practice of the sytem. Digoxin concentrations were measured in serum by TDxFlex (Abbott Laboratories, U.S.A.). Each patient's digoxin pharmacokinetics was determined by using the Abbott-base Pharmacokinetics system (Abbott Laboratories, U.S.A.) . The interpretation for the assayed digoxin level, the recommendation of maintenance dosage and the simulation graph with predicted serum levels were included in the report. The effectiveness of the reporting system was evaluated by comparing the appropriateness of digoxin level measurement between both groups. RESULTS: It revealed that appropriate measurements of digoxin level were 59.5 % of the tests in A group and 77.1% of those in B group (p=0.006). Evaluation of serum digoxin concentrations stratified by digoxin concentration showed also significant difference among the percentage of tests in each concentration range between both groups (p=0.011). CONCLUSIONS: Interpretative report system for the assayed results caused to increase in the appropriateness of digoxin measurement. The report system with some improvement which is achieved through the active approach to physician helps us use TDM effectively. The system can be applied to the other TDM drugs.
Digoxin ; Drug Monitoring* ; Humans ; Inpatients ; Pharmacokinetics

BACKGROUND: Methylmalonic aciduria can be caused by inherited defects in the methylmalonyl-CoA mutase enzyme, Inherited defects in the metabolism of vitamin Bl2 and acquired or inherited vitamin Bl2 deficiency. Quantitation of urinary methylmalonic acid (MMA) is very useful In diagnosis of methylmalonic acidemia and cobalamin deficiency. We evaluated a quantitation method of urinary MMA and determined reference values. METHODS: The method involved stable isotope dilution gas chromatographymass spectrometry (GC-MS) with (methyl 2H3)-MMA as the internal standard. We determined the detection limit, linearity and periodic variations of the assay. Urinary MMA levels were measured in 70 individuals of ages newborn to 58 years with no metabolic disorders. RESULTS: The lower limit of detection calculated from blank runs (mean+/-3SD) was 2.62nmo1/m1. One control urine tramp)e analyzed 23 times within 3 weeks game results of 7.83+/-1.09 (mean+/-SD, CV=13.8%) nmol/mL. The linearity at four different concentrations of MMA was acceptable (R2=0.9992). The concentration of urinary MMA in 70 individuals was 2.33+/-2.19 mmol/mol creatinine (mean+/-SD). Age related reference values which decreased with age were also reported (p=1.23x10-9). CONCLUSIONS: The described method is sensitive, specific and noninvasive, which is considered the gold standard method for measuring MMA. The method could be used as a screening test for cobalamin deficiency and inherited methyl malonic acidemia. On the basis of the narrow range of normal concentration, it is expected that the method would readily detect mild cobalamin deficiency.
Chromatography, Gas* ; Creatinine ; Diagnosis ; Gas Chromatography-Mass Spectrometry* ; Humans ; Infant, Newborn ; Limit of Detection ; Mass Screening ; Metabolism ; Methylmalonic Acid* ; Methylmalonyl-CoA Mutase ; Reference Values ; Spectrum Analysis ; Vitamin B 12 ; Vitamins

PURPOSE: Recently, two tests are commercially available for the identification of latent tuberculosis infection (LTBI): tuberculin skin test (TST) and interferon-gamma release assay (IGRA). Due to its false positiveness, TST tends to be preferred by IGRA until now. In our study, we simultaneously performed both TST and QuantiFERON(R)-TB Gold In-Tube (QFT-GIT) and compared their results. METHODS: TST and QFT-GIT were done for the diagnosis of LTBI among children who visited pediatric out-patient clinic at St. Vincent's Hospital, The Catholic University of Korea from February of 2007 to May of 2008. The study group was stratified into two groups in terms of whether there was intrafamilial contact or not. RESULTS: Out of total 35 children, 29 were tuberculosis (TB)-exposed cases and the remainders were diagnosed as clinical pulmonary TB. Among these 29 children, TST was positive 38.9% (7/18) for the intrafamilial and 45.5% (5/11) for the non-intrafamilial, and at the same time, the result for QFT-GIT was positive 5.6% (1/18) and 9.1% (1/11), respectively which implies that TST was more sensitive than QFT-GIT. Among 29 TB-exposed cases, 26 initially went through TST and QFT-GIT together on their first visit to out-patient clinic, and 15 continued the follow-up tests. Out of total 41 cases collected, the agreement (known as kappa value) was 0.063 which was relatively low. Including 6 cases with pulmonary TB who were all positive for TST and only 5 being positive for QFT-GIT, the final kappa value was 0.334. CONCLUSION: In our study, the agreement for TST and QFT-GIT was low, and the majorities were almost the cases of positive TST. In current situation with lacking a gold standard test and limited data on children to adolescents, this result is quite alarming that the recent trend tends to replace TST by QFT-GIT when diagnosing LTBI.
Adolescent ; Child ; Follow-Up Studies ; Humans ; Interferon-gamma Release Tests ; Korea ; Latent Tuberculosis ; Outpatients ; Skin ; Skin Tests ; Tuberculin ; Tuberculosis