• Title/Summary/Keyword: Epidemiological

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Application of Giemsa stain for easy detection of Trichinella spiralis muscle larvae

  • Ramirez-Melgar, Carmen;Gomez-Priego, Alberto;De-La-Rosa, Jorge-Luis
    • Parasites, Hosts and Diseases
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    • v.45 no.1 s.141
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    • pp.65-68
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    • 2007
  • The application of Giemsa technique to stain compressed diaphragm samples obtained from rodents experimentally infected with Trichinella spiralis is described. Diaphragm samples from rats heavily infected with 20 muscle larvae per gram of body weight(20 ML/gbw) were cut into several pieces and stained with Giemsa; on the other hand, whole diaphragms from slightly infected mice(1 ML/gbw) were also stained with Giemsa. Besides, muscle samples were also stained with Giemsa. Observation at 10 $\times$ magnification revealed that both ML and nurse cells(NC) look as bluish structures clearly contrasting with the pinkish color of the non-infected muscle fibers. NC in the diaphragms of mice could be easily observed at naked eye as blue points contrasting with the pink surrounding areas formed by the non-infected muscle fibers. Among NC observed in the diaphragms of rats infected with 20 ML/gbw, 4.4% was multiple infection. These findings were confirmed in sectioned and hematoxylin-eosin stained specimens. This data could be usefulness for a rapid diagnosis of trichinellosis in post-mortem mammals without magnification procedures.

Methyl Isocyanate and Carcinogenesis: Bridgeable Gaps in Scientific Knowledge

  • Senthilkumar, Chinnu Sugavanam;Sah, Nand Kishore;Ganesh, Narayanan
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2429-2435
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    • 2012
  • Methyl isocyanate may have a role in cancer etiology, although the link is unclear. There is evidence in the literature that it can induce cancer in animals but the carcinogenic potency is weak. Pheochromocytoma of adrenal medulla and acinar cell tumors of pancreas have been observed in methyl isocyanate exposed animals. Conversely, emerging data from population-based epidemiological studies are contradictory since there is no evidence of such cancers in methyl isocyanate exposed humans. Recently, we reported a high prevalence of breast and lung cancers in such a population in Bhopal. In vitro findings appearing in the latest scientific literature suggest that genomic instability is caused by methyl isocyanate analogs in lung, colon, kidney, ovary epithelial cells, and that hepatocytes may undergo oncogenic transformation, have obvious implications. The conflicting information prompted us to present this update over the last three decades on methyl isocyanate-induced cancers after an extensive literature search using PubMed. While the pertinent literature remains limited, with a scarcity of strong laboratory analyses and field-epidemiological investigations, our succinct review of animal and human epidemiological data including in vitro evidences, should hopefully provide more insight to researchers, toxicologists, and public health professionals concerned with validation of the carcinogenicity of methyl isocyanate in humans.

An epidemiological study on the malaria for residents in Kangwha-Gun(1999) (경기 강화지역 주민에 대한 말라리아의 역학적 특성에 관한 연구(1999년))

  • 김경호;조남규;고종명;김용희
    • Korean Journal of Veterinary Service
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    • v.23 no.1
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    • pp.9-17
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    • 2000
  • Epidemic malaria is prevalent in the demilitarized zone and the northern area of Kyonggi province in Korea. Malaria has broken out in Gangwha-Gun since 1997 due to geographical condition. The results obtained from an epidemiological surveillance for the malaria that happened in 1999 were as follows ; Anopheles sinensis collected in UV-light traps in the barn in Wolgogri and Dangsanri of Songhaemyon showed the distribution of 27,156 of 49,280 figures, corresponding to 55.1%, between July and August. The numbers of patients with malaria were 48(32.4%) in July, 36(24.3%) in August, and 38(25.7%) in September with a prevalence with the ages of the twenties to the seventies. Of a total 154 patients, the male were 86(58.1%) and the female were 68(41.8%). The annual parasite index(API) were 6.44, 5.89 and 4.45 in Songhaemyon, Yangsamyon and Kyodongmyon, respectively. A high infection rate was found Particularly in the areas within 2km from the Han river. By the immunofluorescence assays(IFA), 26 cases were positive with an antibody titers of $\geq$ 1 : 32, of 220 residents in Songhaemyon and 336 ones with a potential case and contacted with the patients. By the blood test, there was no significance in alkaline phosphatase, alanine aminotransferase, total cholesterol, glucose, hemoglobin, hematocrit, white blood cell, red blood cell, and platelet between residents with an antibody titers of $\geq$ 1 : 32 and < 1 : 32 in Songhaemyon.

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Epidemiological Trend of Japanese Encephalitis in Korea (우리나라 일본뇌염유행(日本腦炎流行)의 추이(趨移) -과거(過去) 20년간(年間)을 중심(中心)으로-)

  • Lee, Chu-Won;Oh, Dae-Kyu
    • Journal of Preventive Medicine and Public Health
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    • v.20 no.1 s.21
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    • pp.137-146
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    • 1987
  • The following facts have been identified as a result of epidemiological trend and characteristic of Japanese Encephalitis in Korea for the last 20 years. First: The Epidemiological period which was ten-year and three-year in the past has been disappeared following the start of immunization program at 1970. Second: The Incidence rate was much higher in the south and West areas than northeast area of Korea. City and Province with the highest incidence rate was Chungcheong Nam Province and Cholla Buk Province. Third: Regardless of scope of prevalence, the main season that 90 percent of total incidence occurrs in one month from mid-August through mid-September. Fourth: The number of case by age was that 80 percent of total patients is children aged $3{\sim}15$. Recently there is an increase in the number of patients who are elderly people. Fifth: The study on the ecological conditions of mosquito including wintering and effectiveness of immunization for Japanese Encephalitis and duration on antibody should be done. Sixth: There has been no case of Japanese Encephalitis for the last three years since 1984 mainly due to disinfecting to eradicate mosquitos, immunization for vulnerable group of people aged $3{\sim}15$, individual precaution not to be bitten by mosquito, improvement of environment sanitation. While there has been no case of Japanese Encephalitis during last three years, there is possibility that Japanese Encephalitis becomes prevalent again anytime since its virus has been isolated continuously from the natural reservoirs.

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Epidemiology and challenges on the Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak in Korea, 2015 (2015년 한국의 중동호흡기증후군 유행 역학과 정책 과제)

  • Lee, Moo-Sik
    • Korean Journal of Health Education and Promotion
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    • v.32 no.3
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    • pp.1-9
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    • 2015
  • Objectives: The purpose of this article was to assess epidemiological characteristics and recommendations for strengthening national response and preparedness after MERS-CoV outbreak in Korea, 2015. Methods: The author reviewed epidemiological reports and policy recommendations on MERS-CoV outbreak in Korea, 2015. Results: There was no evidence that genetical difference between the MERS viruses in the Republic of Korea and recent viruses in the Middle East. From the index case to last laboratory-confirmed case, there were 186 laboratory-confirmed cases that included 36 deaths(19.4%), all of whom appear epidemiologically linked to the index cases or subsequent secondary, tertiary, and quaternary cases. This outbreak spread to hospitals through nosocomial transmission. At least, three large clusters were investigated. However, there was at least one case of community transmission of MERS-CoV. Several factors had contributed to the MERS outbreak in Korea, 2015 that including epidemiological characteristics, and infrastructure of national healthcare system for preventing and controlling emerging infectious diseases. Conclusions: It is very important that to share experiences and identify underlying causes of this outbreak for prevention and control of emerging infectious disease in the future; including epidemiology, clinical features, and public health response and preparedness.

Linear Mixed Models in Genetic Epidemiological Studies and Applications (선형혼합모형의 역할 및 활용사례: 유전역학 분석을 중심으로)

  • Lim, Jeongmin;Won, Sungho
    • The Korean Journal of Applied Statistics
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    • v.28 no.2
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    • pp.295-308
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    • 2015
  • We have experienced a substantial improvement in and cost-drop for genotyping that enables genetic epidemiological studies with large-scale genetic data. Genome-wide association studies have identified more than ten thousand causal variants. Many statistical methods based on linear mixed models have been developed for various goals such as estimating heritability and identifying disease susceptibility locus. Empirical results also repeatedly stress the importance of linear mixed models. Therefore, we review the statistical methods related with to linear mixed models and illustrate the meaning of their estimates.

The Linear No-Threshold Model in Epidemiological Studies: An Example of Radiation Exposure (역학연구에서의 비역치선형모델: 방사선 노출 사례)

  • Won Jin Lee
    • Journal of Environmental Health Sciences
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    • v.50 no.4
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    • pp.229-236
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    • 2024
  • The linear no-threshold (LNT) model is an assumption that explains the dose-response relationship for health risks, allowing for linear extrapolation from high doses to low doses without a threshold. The selection of an appropriate model for low-dose risk evaluation is a critical component in the risk assessment process for hazardous agents. This paper reviews the LNT model in light of epidemiological evidence from major international consortia studying ionizing radiation. From a scientific perspective, substantial evidence supporting the LNT model has been observed in epidemiological studies of low-dose ionizing radiation exposure, although some findings suggest non-linear dose relationships for certain cancer sites and variations across populations. From a practical standpoint, the LNT remains the most useful model for radiation protection purposes, with no alternative dose-response relationship proving more appropriate. It is important to note that the LNT model does not directly reflect the magnitude of risk at the population level, and this distinction should be clearly communicated to the public. While applying the LNT model as the principal basis for radiation protection, continuous research into various dose-response relationships is crucial for advancing our understanding.