• Parasites, Hosts and Diseases
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• 제44권3호
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• pp.209-219
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• 2006

Toxoplasma gondii has been shown to result in life-threatening encephalitis in immunocompromised patients after reactivation of dormant parasites. In order to obtain information on immune responses related to this phenomenon, BALB/c mice were infected with 25 cysts of the 76K strain of T. gondii, then, treated orally with dexamethasone (Toxo/Dexa-treated group) in order to reactivate the chronic toxoplasmosis. None of the T. gondii-infected mice died during the experimental periods, whereas the Toxo/Dexa-treated mice evidenced a significant attenuation of survival periods. Toxoplasma-specific IgG2a, IgA and IgM titers in sera were significantly depressed in the Toxo/Dexa-treated mice; however, the IgG1 sera titers were similar to those seen in the Toxoplasma-infected mice. The percentages of CD4+ and $CD8\alpha+$ T cells in the Toxo/Dexa-treated mice were significantly reduced 2 weeks after dexamethasone treatment. $IFN-\gamma$ and IL-10 production levels in the Toxo/Dexa-treated mice were depressed significantly, whereas IL-4 production was increased temporarily. The expression levels of the Toxoplasma-specific P30 and B1 genes were found to have been increased in the Toxo/Dexa-treated mice in comparison with the Toxoplasma-infected mice. Collectively, the findings of this study demonstrate that reactivation of murine toxoplasmosis as the result of dexamethasone treatment induced a depression in Th1 immune responses, whereas Th2 immune responses were not significantly influenced.

• Parasites, Hosts and Diseases
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• 제41권3호
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• pp.147-154
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• 2003

Toxoplasma gondii tachyzoites were isolated from the blood of an ocular patient, and have been successfully passaged in the laboratory, for over a year, by peritoneal inoculation in mice. The isolated parasite was designated the Korean Isolate-1 (KI-1) and its characteristics were compared with those of the RH strain, a well-known virulent strain originating from a child who suffered from encephalitis. The morphology, pathogenicity, infectivity and cell culture characteristics of the KI-1 were similar to those of the RH strain. Both RH and KI-1 antigens were detected by an anti-T gondii monoclonal antibody (mAb), Tg563, against the major surface protein SAG1 (30 kDa), whereas no reaction was observed against an anti-Neospora caninum mAb, 12B4. The KI-1 was confirmed as an isolate of T. gondii. A long-term laboratory maintenance and characterization of a local T gondii isolate is reported for the first time in the Republic of Korea.

• Parasites, Hosts and Diseases
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• 제40권1호
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• pp.17-24
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• 2002

We have cloned a cDNA encoding a cysteine proteinase of the Acanthamoeba healui OC-3A strain isolated from the brain of a granulomatous amoebic encephalitis patient. A DNA probe for an A. healui cDNA library screening was amplified by PCR using degenerate oligonucleotide primers designed on the basis of conserved amino acids franking the active sites of cysteine and asparagine residues that are conserved in the eukaryotic cysteine proteinases. Cysteine proteinase gene of A. healui (AhCPI) was composed of 330 amino acids with signal sequence, a proposed pro-domain and a predicted active site made up of the catalytic residues, $Cys^{25},{\;}His^{159},{\;}and{\;}Asn^{175}$. Deduced amino acid sequence analysis indicates that AhCPI belong to ERFNIN subfamily of C 1 peptidases. By Northern blot analysis. no direct correlation was observed between AhCPI mRNA expression and virulence of Acanthamoeba, but the gene was expressed at higher level in amoebae isolated from soil than amoeba from clinical samples. These findings raise the possibility that AhCPI protein may play a role in protein metabolism and digestion of phagocytosed bacteria or host tissue debris rather than in invasion of amoebae into host tissue.

• Parasites, Hosts and Diseases
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• 제54권4호
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• pp.447-453
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• 2016

Acanthamoeba, a free-living amoeba, is widely distributed in the environment, water sources, soil, dust, and air. It can cause keratitis in contact lens wearers with poor hygiene and also fatal granulomatous amebic encephalitis (GAE) in immunocompromised hosts. The aim of this study was to gain some insights into the distribution and genotypes of the potentially pathogenic species of Acanthamoeba present in water sources in north of Iran. Total 43 Acanthamoeba species were isolated from 77 water samples taken from different water sources within the Mazandaran province in Northern Iran (Sari city and suburbs). Isolates were identified based on cyst and trophozoite morphological characteristics as well genetics. PCR fragments corresponding to the small-subunit 18S rRNA gene were sequenced for 20 of 43 positive isolates. The results revealed that 83.3% of sequenced isolates belonged to the T4 genotype and the rest belonged to the T2 genotype. Our results indicated that Acanthamoeba is widely distributed in Sari city. As the incidence in Iran of amoebic keratitis has increased in recent years, the exact estimation of the prevalence of this amoeba and its predominant genotype may play a crucial role in prevention of the disease. Sari city has several rivers, seashores, and natural recreational amenities, which attract visitors during the year. This is the first report of Acanthamoeba genotypes from water sources in Sari city, Mazandaran province of Iran, and the results suggest that more attention is needed to protect the visiting population and immunocompromised individuals.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2009년도 정기총회 및 국제심포지엄
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• pp.228-239
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• 2009

The observations on climate change show a clear increase in the temperature of the Earth's surface and the oceans, a reduction in the land snow cover, and melting of the sea ice and glaciers. The effects of climate change are likely to include more variable weather, heat waves, increased mean temperature, rains, flooding and droughts. The threat of climate change and global warming on human and animal health is now recognized as a global issue. This presentation is described an overview of the latest scientific knowledge on the impact of climate change on zoonotic diseases. Climate strongly affects agriculture and livestock production and influences animal diseases, vectors and pathogens, and their habitat. Global warming are likely to change the temporal and geographical distribution of infectious diseases, including those that are vector-borne such as West Nile fever, Rift Valley fever, Japanese encephalitis, bluetongue, malaria and visceral leishmaniasis, and other diarrheal diseases. The distribution and prevalence of vector-borne diseases may be the most significant effect of climate change. The impact of climate change on the emergence and re-emergence of animal diseases has been confirmed by a majority of countries. Emerging zoonotic diseases are increasingly recognized as a global and regional issue with potential serious human health and economic impacts and their current upward trends are likely to continue. Coordinated international responses are therefore essential across veterinary and human health sectors, regions and countries to control and prevent emerging zoonoses. A new early warning and alert systems is developing and introducing for enhancing surveillance and response to zoonotic diseases. And international networks that include public health, research, medical and veterinary laboratories working with zoonotic pathogens should be established and strengthened. Facing this challenging future, the long-term strategies for zoonotic diseases that may be affected by climate change is need for better prevention and control measures in susceptible livestock, wildlife and vectors in Korea. In conclusion, strengthening global, regional and national early warning systems is extremely important, as are coordinated research programmes and subsequent prevention and control measures, and need for the global surveillance network essential for early detection of zoonotic diseases.

• 대한미생물학회지
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• 제12권1호
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• pp.51-56
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• 1977

자세한 원인은 잘 모르나 1969년 이후 한국의 일본뇌염 발생율은 과거에 비하여 현저하게 감소되었다. 따라서 본 연구는 최근 한국 자연계에 있어서의 한국인의 일본뇌염 바이러스에 대한 감염빈도를 알아보고저 실시된 실험이다. 검사물은 1975년 1월부터 동년 12월까지 성모병원에 래원한 환자의 일반 검사용혈청(총 1,204명중 남자 574명, 여자 630명)을 대상으로 하여 일본뇌염 바이러스에 대한 혈구응집저지(Clarke & Casals법) 항체의 분포를 조사한 실험결과이다. 1. 총 1,204명을 검사한 바 10배 이상의 일본뇌염바이러스에 대한 항체보유율은 57.6%이고, 이중 남자가 58.1%이고 여자는 57.1%였다. 2. 월별 항체보유율은 10월이 91.2%로 가장 높았고 12월이 32.9%로 낮았다. 기타는 그 중간이었다. 3. 연령별 항체보유율은 대체로 연령이 증가함에 따라 항체보유율이 높았다. 본 실험에서 한국인에게 나타난 일본뇌염에 대한 항체의 보유율은 아직도 많은 사람들이 일본뇌염 바이러스에 대한 계속 불현성감염을 받고 있다는 사설을 알 수 있었다.

• 대한의생명과학회지
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• 제21권1호
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• pp.9-14
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• 2015

Mouse hepatitis virus (MHV) is a major pathogen in laboratory mice that usually leads to fatal diseases, such as hepatitis, multiple sclerosis, encephalitis, and respiratory disease. MHV has a high infection rate, and it needs to be detected as soon as possible to prevent its spread to other facilities. However, MHV detection by enzyme-linked immunosorbent assay (ELISA) often gives false positives; thus, it is very important that the results are confirmed as true positives in the early infection stage or distinguished as false positives with more accurate, reliable methods. Under microbiological screening, MHV ELISA-positive mice were found in four GFP-tagging transgenic mice. To verify the detection of the MHV antigen directly, reverse transcription polymerase chain reaction (RT-PCR) was performed, and the mice were determined to be MHV negative. Additional serum antibody-based screening was conducted with three different ELISA kits, and multiplexed fluorometric immunoassay (MFIA) was performed to confirm their accuracy/sensitivity. In brief, the ELISA kit for A59 nucleocapsid protein (MHV-A59N) revealed MHV ELISA positivity, while other ELISA kits (MHV-S lysate and MHV-JHM lysate) demonstrated MHV negativity. In MFIA, only the test for the recombinant A59 nucleocapsid antigen was MHV positive, which was consistent with the ELISA results. These results suggest that the ELISA kit with the recombinant A59 nucleocapsid antigen might induce non-specific MHV ELISA positivity and that confirmation is therefore essential.

• 생물정신의학
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• 제21권2호
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• pp.37-48
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• 2014

Besides from medical data, the patients who were previously called as attention disorder, mental instability, moral imbeciles, or moral defectives, can also be identified by exploring literatures and historical figures. In the past, as we can notice from the titles, they were recognized as a 'moral defect group'. And rather than treating them, separation from the society was the main solution. After the endemic encephalitis from 1917 to late 1920s, however, many survivors suffered from behavioral problems similar to those of the previous 'moral defect group' and studies on the relationship between brain damage and behavior problems were started henceforth. After being known as the 'minimal brain dysfunction', it was developed into the current attention-deficit/hyperactivity disorder. While the disease concept changed and developed over time, after numerous trials and errors, treatment medication starting from central nervous system stimulants such as amphetamine and methylphenidate is used for treatment in children and adult patients with ADHD, and most recently non-stimulants such as atomoxetine has become the one of the first line treatment options. Although we went through a thorough verification process of the safety and efficacy of the medication by contemplating the historical development process, we believe that adjustment is needed for remaining concerns on medication abuse and slight differences in disease paradigm and therapeutic philosophy depending on cultures.

• Clinical and Experimental Pediatrics
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• 제54권1호
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• pp.11-16
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• 2011

Purpose: Enterovirus 71, one of the enteroviruses that are responsible for both hand-foot-and-mouth disease and herpangina, can cause neural injury. During periods of endemic spread of hand-foot-andmouth disease caused by enterovirus 71, CNS infections are also frequently diagnosed and may lead to increased complications from neural injury, as well as death. We present the results of our epidemiologic research on the clinical manifestations of children with CNS infections caused by enterovirus 71. Methods: The study group consisted of 42 patients admitted for CNS infection by enterovirus 71 between April 2009 and October 2009 at the Department of Pediatrics of 5 major hospitals affiliated with the Catholic University of Korea. We retrospectively reviewed initial symptoms and laboratory findings on admission, the specimen from which enterovirus 71 was isolated, fever duration, admission period, treatment and progress, and complications. We compared aseptic meningitis patients with encephalitis patients. Results: Of the 42 patients (23 men, 19 women), hand-foot-and-mouth disease was most prevalent (n=39), followed by herpangina (n=3), upon initial clinical diagnosis. Among the 42 patients, 15 (35.7%) were classified as severe, while 27 (64.3%) were classified as mild. Factors such as age, fever duration, presence of seizure, and use of intravenous immunoglobulin (IVIG) were statistically different between the 2 groups. Conclusion: Our results indicate that patients with severe infection caused by enterovirus 71 tended to be less than 3 years old, presented with at least 3 days of fever as well as seizure activity, and received IVIG treatment.

• 동의생리병리학회지
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• 제22권1호
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• pp.96-99
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• 2008

Toxoplasma gondiiis a widespread apicomplexan parasite which is able to infect virtually all warm-blooded vertebrates. Twenty-two percent of the U.S. population is infected, but severe disease in adults is mainly limited to immunosuppressed patients. In patients with acquired immunodeficiency syndrome(AIDS), T. gondii causes a life-threatening opportunistic infection, with Toxoplasma encephalitis as its most severe manifestations. T. gondii is also known to cause congenital infection and is among the pathogens with the highest incidence of complications in pregnancies. Despite its clinical importance, only very few therapeutic drugs against T. gondii are available, all of which target the rapidly dividing tachyzoites, leaving the dormant encysted bradyzoite stage unaffected. We searched 15 traditional medicines that have anti-inflammatory effect from dongyibogam and Traditional Chinese medicine. In vitro studies were performed with HeLa cell cultures, with quantification of Toxoplasma growth by a cell proliferation assay. The result of experiment shows the selectivity of Citrus unshiu Markovich is 6.0. This is higher than sulfadiazine (selectivity was 1.63). For in vivo studies, mice were acutely infected intraperitoneally with $10^5$ tachyzoites of the virulent RH strain and then treated per orally for 4 days from 6 hours postinfection. Efficacy was assessed by sequential determination of parasite burdens in peritoneal cavity. In vivo, Citrus unshiu Markoviche inhibited Toxoplasma growth at a concentration of 10㎎/㎏ of body weight per day, the inhibition ratio was estimated to be 64.01%.