• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7603-7609
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• 2014

Glutathione is a thiol compound that plays an important role in the antioxidant defense system of the cell and its deficiency leads to an increased susceptibility to oxidative stress and, thus, progression of many disease states including head and neck cancer. In the present study, alterations of glutathione levels were investigated in study cohort of 500 samples (cohort 1 containing 200 head and neck cancer blood samples along with 200 healthy controls and cohort II with 50 head and neck squamous cell carcinoma tissue samples along with 50 control tissues) by high performance liquid chromatography. The results indicated that mean blood glutathione levels were significantly reduced in head and neck cancer patients (p<0.001) compared to respective controls. In contrast, the levels of glutathione total (p<0.05) and glutathione reduced (p<0.05) were significantly elevated in head and neck squamous cell carcinoma tissues compared to the adjacent cancer-free control tissues. In addition to this, pearson correlation performed to correlate different tissue glutathione levels (GSH) with clinical/pathological parameters demonstrated a significant negative correlation between pT-stage and GSH level ($r=-0.263^{**}$; p<0.01), C-stage and GSH level ($r=-0.335^{**}$; p<0.01), grade and GSH ($r=-0.329^{**}$; p<0.01) and grade versus redox index ($r=-0.213^{**}$; p<0.01) in HNSCC tissues. Our study suggests that dysregulation of glutathione levels in head and neck cancer has the potential to predict metastasis, and may serve as a prognostic marker.

• Korean Medical Education Review
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• v.25 no.2
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• pp.84-101
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• 2023

Longitudinal data can provide important evidence with the potential to stimulate innovation and affect policies in medical education and can serve as a driving force for further developments in medical education through evidence-based decisions. Tracking and observing cohorts of students and graduates using longitudinal data can be a way to link the past, present, and future of medical education. This study reviewed practical methods and technical, administrative, and ethical considerations for the establishment and operation of a longitudinal database and presented examples of longitudinal databases. Cohort study design methods and previous examples of research using longitudinal databases to explore major topics in medical education were also reviewed. The implications of this study are as follows: (1) a systematic design process is required to establish longitudinal data, and each university should engage in ongoing deliberation about this issue; (2) efforts are needed to alleviate "survey fatigue" among respondents and reduce the administrative burden of those conducting data collection and analysis; (3) it is necessary to regularly review issues of personal information protection, data security, and ethics regarding the survey respondents; and (4) a system should be established that integrates and manages a longitudinal database of medical education at the national level. The hope is that establishing longitudinal data and cohorts at individual medical schools will not be a temporary phenomenon, but rather that they will be well utilized at the national level to innovate and implement ongoing changes in medical education.

• Journal of Preventive Medicine and Public Health
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• v.57 no.1
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• pp.55-64
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• 2024

Objectives: This study investigated the prevalence and characteristics of comorbid conditions in patients exposed to ionizing radiation and those who were involved in the Soviet-Afghan war. Methods: This study analyzed the frequency and spectrum of morbidity and comorbidity in patients over a long-term period (30-35 years) following exposure to ionizing radiation at the Semipalatinsk nuclear test site or the Chornobyl nuclear power plant, and among participants of the Soviet-Afghan war. A cohort study, both prospective and retrospective, was conducted on 675 patients who underwent comprehensive examinations. Results: Numerical data were analyzed using the Statistica 6 program. The results are presented as the mean±standard deviation, median, and interquartile range (25-75th percentiles). The statistical significance of between-group differences was assessed using the Student t-test and Pearson chi-square test. A p-value of less than 0.05 was considered statistically significant. We found a high prevalence of cardiovascular diseases, including hypertension (55.0%) and cardiac ischemia (32.9%); these rates exceeded the average for this age group in the general population. Conclusions: The cumulative impact of causal occupational, environmental, and ultra-high stress factors in the combat zone in participants of the Soviet-Afghan war, along with common conventional factors, contributed to the formation of a specific comorbidity structure. This necessitates a rational approach to identifying early predictors of cardiovascular events and central nervous system disorders, as well as pathognomonic clinical symptoms in this patient cohort. It also underscores the importance of selecting suitable methods and strategies for implementing treatment and prevention measures.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.3
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• pp.88-98
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• 2002

The multilayer perceptron (MLP) has several advantages against other pattern recognition methods, and is expected to be used as the learning and recognizing speakers of speaker verification system. But because of the low learning speed of the error backpropagation (EBP) algorithm that is used for the MLP learning, the MLP learning requires considerable time. Because the speaker verification system must provide verification services just after a speaker's enrollment, it is required to solve the problem. So, this paper tries to make short of time required to enroll speakers with the MLP based speaker verification system, using the method of improving the EBP learning speed and the method of reducing background speakers which adopts the cohort speakers method from the existing speaker verification.

• Childhood Kidney Diseases
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• v.27 no.2
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• pp.111-116
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• 2023

Purpose: This article was to investigate the association between urinary tract infections (UTIs) and high weight status in infancy. Methods: We conducted a nationwide matched cohort study from January 2018 to December 2020 using data from the Korean National Health Insurance System and the Korean National Health Screening Program for Infants and Children. We analyzed the association between UTI diagnosis codes and high weight status (which was defined as being in the 90th percentile or higher of weight-for-age). Results: We found that 22.8% of infants with UTIs exhibited high weight status, compared to 20.0% of non-UTI infants (P<0.001). Per our multivariable analyses, the adjusted odds ratio for high weight status was 1.09 (95% confidence interval, 1.06-1.13). Conclusions: UTI in the first 12 months of life was associated with a weight-for-age percentile of ≥90. Our findings corroborate those of previous single-center studies and emphasize the importance of careful monitoring for this at-risk group.

• Journal of Preventive Medicine and Public Health
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• v.33 no.1
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• pp.76-82
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• 2000

Objectives : We attempted to assess He accuracy of ICD codes for cerebrovascular diseases in medical insurance claims (ICMIC) and to investigate the reasons for error. This study was designed as a preliminary study to establish a nationwide surveillance system. Methods : A total of 626 patients with medical insurance claims who indicated a diagnosis of cerebrovascular diseases during the period from 1993 to 1997 was selected from the Korea Medical Insurance Corporation cohort (KMIC cohort: 115,600 persons). The KMIC cohort was 10% of those insured who had taken health examinations in 1990 and 1992 consecutively. The registered medical record administrators were trained in the survey technique and gathered data from March to May 1999. The definition of cerebrovascular diseases in this study included cases which met ore of two criteria (Minnesota, WHO) or 'definite stroke' in CT/MRI finding. We questioned the medical record administrators to explain the error if the final diagnoses were not coded as stroke. Results : The accuracy rate of the ICMIC was 83.0% (425 cases) Medical records were not available for 8.2% (51 cases) due to the closing of hospitals, the absence of a computer system or omission of medical record, etc. Sixty-three cases (10.0%) were classified as impossible to interpret due to insufficient records in 'major clinical symptoms' or 'neurological deficits'. The most common reason was 'to meet review criteria of medical insurance benefits (52.9%)'. The department where errors in the ICMIC occurred most frequently was the department for medical insurance claims in the hospital. Conclusion : The accuracy rate of the ICMIC was 83.0%.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.571-573
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• 2004

Speaker verification systems based on multilayer perceptrons (MLPs) have good prospects in reliability and flexibility required as a successful authentication system. However, the poor learning speed of the error backpropagation (EBP) which is representative learning method of MLPs is the major defect to be complemented to achieve real-time user enrollments. In this paper, we implement an MLP-based speaker verification system and apply the existing two methods of the omitting patterns in instant learning (OIL) and the discriminative cohort speakers (DCS) to approach real-time enrollment. An evaluation of the system on a Korean speech database demonstrates the feasibility of the system as a speaker verification system of high performance.

• Korea journal of population studies
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• v.29 no.2
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• pp.53-88
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• 2006

The major aim of this paper is to develop a hypothetical set of age-specific fertility rates which are logically derived and reasonably accurate in the projection of future population. The first procedure is to select a generalized log-gamma distribution model, which includes Coale-McNeil nuptiality model, in order to estimate and project a set of age-specific fertility rates by birth cohort and birth order. The second is to apply the log-gamma model with an empirical adjustment to the actual data to estimate and project the future fertility rates for relatively young birth cohorts who did not complete their reproductive career. This study reconstructs or translates a set of cohort age-specific fertility rates into a set of period age-specific fertility rates which must be hypothesized in order to establish the broader framework of future population projection. For example, the fertility at age 20 in the year of 2020 is the fertility at age 20 for the cohort born in 1990, while the fertility at age 21 in the year of 2020 is the fertility at 21 for the cohort born in 1989. In turn, once a set of age-specific fertility rates for the cohorts who were born up to the year of 2010, it is possible for one to establish an hypothetical set of period age-specific fertility rates which will be needed to project the future population until the year of 2055. The difference in the hypothetical system of age-specific fertility rates between this study and the 2005 special population projection comes from the fact that the fertility estimation/projection model used in this study was skillfully exploited to reflect better actual trend of fertility decline caused by rise in marriage age and increasing proportion of those who remain single until their end of reproduction. In this regard, this paper argues that the set of age-specific fertility rates derived from this study is more logical and reasonably accurate than the set of those used for the 2005 special projection. In the population projection, however, the fundamental issue of the hypothetical setting of age-specific fertility rates in relation to the fertility estimation/projection model is about how skillfully one can handle the period effects. It is not easy for one to completely cope with the problem of period effects except for the a minor period adjustment based on recent actual data, along with the given framework of a cohort-based fertility estimation/projection model.

• Journal of Chest Surgery
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• v.54 no.2
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• pp.88-98
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• 2021

Background: This study aimed to develop a new risk prediction model for operative mortality in a Korean cohort undergoing heart valve surgery using the Korea Heart Valve Surgery Registry (KHVSR) database. Methods: We analyzed data from 4,742 patients registered in the KHVSR who underwent heart valve surgery at 9 institutions between 2017 and 2018. A risk prediction model was developed for operative mortality, defined as death within 30 days after surgery or during the same hospitalization. A statistical model was generated with a scoring system by multiple logistic regression analyses. The performance of the model was evaluated by its discrimination and calibration abilities. Results: Operative mortality occurred in 142 patients. The final regression models identified 13 risk variables. The risk prediction model showed good discrimination, with a c-statistic of 0.805 and calibration with Hosmer-Lemeshow goodness-of-fit p-value of 0.630. The risk scores ranged from -1 to 15, and were associated with an increase in predicted mortality. The predicted mortality across the risk scores ranged from 0.3% to 80.6%. Conclusion: This risk prediction model using a scoring system specific to heart valve surgery was developed from the KHVSR database. The risk prediction model showed that operative mortality could be predicted well in a Korean cohort.

• Journal of Korean Medicine Rehabilitation
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• v.27 no.3
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• pp.117-124
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• 2017

Objectives Collaboration medicine means cooperate with western medicine and traditional korean medicine to treat the one disease. In Korea, Interest in collaboration medicine is increasing, But the number of studies is scare. Therefore we will conduct collaboration medicine study for the low back pain. Methods This study composes prospective cohort registry study. If the patients who need collaboration medicine by doctor come, we will ask regist this study. And patient select collaboration treatment group and single treatment group. Total 120 patients will recruit from collaboration pilot project hospitals. Each group patient will observed 4 weeks. Telephone research will conducted after 1 month from the last follow up. During the treatment, patients are treated usual treatment type of each medicine. Primary outcome is NRS and secondary outcomes are EQ-5D and ODI. We will analyze difference of 1 week and 4 week outcome result. Conclusions This study is the first large sample size study effect of collaboration medicine in Korea for low back pain. We check present collaboration system and improve collaboration system. Aim of this study is to find the effectiveness collaboration medicine for low back pain in the real condition. And we expect this pilot study will provide the clinical collaboration information and basis.