• BMB Reports
• /
• 제56권12호
• /
• pp.669-674
• /
• 2023

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to various clinical symptoms including anemia. Lipocalin-2 has various biological functions, including defense against bacterial infections through iron sequestration, and it serves as a biomarker for kidney injury. In a human protein array, we observed increased lipocalin-2 expression due to parental SARS-CoV-2 infection in the Calu-3 human lung cancer cell line. The secretion of lipocalin-2 was also elevated in response to parental SARS-CoV-2 infection, and the SARS-CoV-2 Alpha, Beta, and Delta variants similarly induced this phenomenon. In a Calu-3 implanted mouse xenograft model, parental SARSCoV-2 and Delta variant induced lipocalin-2 expression and secretion. Additionally, the iron concentration increased in the Calu-3 tumor tissues and decreased in the serum due to infection. In conclusion, SARS-CoV-2 infection induces the production and secretion of lipocalin-2, potentially resulting in a decrease in iron concentration in serum. Because the concentration of iron ions in the blood is associated with anemia, this phenomenon could contribute to developing anemia in COVID-19 patients.

• Journal of Veterinary Science
• /
• 제23권3호
• /
• pp.41.1-41.15
• /
• 2022

Background: Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium. Objectives: This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue. Methods: We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis. Results: The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × 10⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses. Conclusions: This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.

• 한국입자에어로졸학회지
• /
• 제16권4호
• /
• pp.73-94
• /
• 2020

Particulate infectious sources, including infectious viruses, can float in the air, causing airborne infections. To prevent indoor airborne infection, dilution control by ventilation and indoor air cleaners are frequently used. In this study, the risk of airborne infection by the operation of these two techniques was evaluated. In case of dilution control by ventilation, a high efficiency air filter was embedded at the inlet of supply air. In this study, infectious source reduction devices such as indoor air cleaner include all kinds of mechanical-filters, UV-photo catalysts and air ionizers through which air flow is forced by fans. Two mathematical models for influenza virus were applied in an infant care room where infants and young children are active, and the risk reduction efficiency was compared. As a result, in the case of individually operating the ventilator or the infectious source reduction device, the airborne infection risk reduction efficiencies were 55.2~61.2% and 53.8~59.9%, respectively. When both facilities were operated, it was found that the risk of airborne infection was reduced about 72.2~76.8%. Therefore, simultaneous operation of ventilation equipment and infectious source reduction device is the most effective method for safe environment that minimizes the risk of airborne infection of respiratory infectious diseases. In the case of a space where sufficient ventilation operation is difficult, it was found that the operation of an infectious source reduction device is important to prevent the spread of infectious diseases. This study is meaningful in that it provides an academic basis for strategies for preventing airborne infection of respiratory infectious diseases.

• 한국산학기술학회논문지
• /
• 제16권4호
• /
• pp.2647-2655
• /
• 2015

본 연구는 보건 계열 대학생을 대상으로 감염관리 시뮬레이션 교육에서 직소모형 협동학습을 적용한 후 감염관리 인식도, 내적동기, 학습만족도의 차이를 통해 프로그램의 효과를 평가하는데 목적이 있다. 연구 참여자는 J시에 소재한 D대학의 보건계열 2학년 학생으로 실험군 27명과 대조군 27명이다. 두군간의 동질성을 평가하기 위해 사전검사로 감염관리 인식도와 내적동기, 학습만족도에 대해 조사하였으며 두군간에는 유의한 차이가 없었다. 실험군을 대상으로 직소모형을 응용한 협동학습, 시뮬레이션 실습, 디브리핑으로 구성된 프로그램을 1회 3시간씩 1주에 2회로 총 12시간을 실시하였고 대조군에게는 전통적인 강의와 시뮬레이션 실습, 디브리핑을 실시하였다. 2주간의 교육 후 연구 대상자 모두에게 감염관리 인식도, 내적동기, 학습만족도를 조사하였다. 연구 결과 감염관리 시뮬레이션 교육에서 직소모형을 적용한 실험군에서 감염관리 인식도와 학습만족도에서 통계적으로 유의하게 향상되었다. 본 연구결과를 바탕으로 다양한 교과목의 보건계열 시뮬레이션 교육에서 직소모형을 적용한 협동학습이 이루어져 효과적인 수업이 이루어지는데 적극적으로 활용될 것을 기대한다.

• Journal of applied mathematics & informatics
• /
• 제33권5_6호
• /
• pp.559-578
• /
• 2015

Human Immune Deficiency Virus (or simply HIV) induces a persistent infection that leads to AIDS causing death in almost every infected individual. As HIV affects the immune system directly by attacking the CD4+ T cells, to exterminate the infection, the natural immune system produces virus-specific cytotoxic T lymphocytes(CTLs) that kills the infected CD4+ T cells. The reduced CD4+ T cell count produce reduced amount of cytokines to stimulate the production of CTLs to fight the invaders that weakens the body immunity succeeding to AIDS. In this paper, we introduce a mathematical model with discrete time-delay to represent this cell dynamics between CD4+ T cells and the CTLs under HIV infection. A modified functional form has been considered to describe the infection mechanism. Characteristics of the system are studied through mathematical analysis. Numerical simulations are carried out to illustrate the analytical findings.

• 대한의용생체공학회:의공학회지
• /
• 제15권3호
• /
• pp.295-304
• /
• 1994

This paper describes some preliminary attempts to formulate simple mathematical models of the transmission dynamics of HIV infection in homosexual communities. In conjunction with a survey of the available epidemiological data on HIV infection and the incidence of AIDS, the model is used to assess how various processes influence the course of the initial epidemic following the introduction of the virus. Models of the early stages of viral spread provide crude methods for estimating the basic reproductive rate of the virus, given a knowledge of the incubation period of AIDS and the initial doubling time of the epidemic. More complex models are formulated to assess the influence of heterogeneity in sexual activity. This latter factor is shown to have a major effect on the predicted pattern of the epidemic.

• Parasites, Hosts and Diseases
• /
• 제45권2호
• /
• pp.103-109
• /
• 2007

Leishmania tropica and L. major are etiologic agents of human cutaneous leishmaniasis. Delayed type hypersensitivity (DTH) is an immunologic response that has been frequently used as a correlate for protection against or sensitization to leishmania antigen. In BALB/c mice, L. tropica infection results in non-ulcerating disease, whereas L. major infection results in destructive lesions. In order to clarify the immunologic mechanisms of these 2 different outcomes, we compared the ability of these 2 leishmania species in induction of DTH response in this murine model. BALB/c mice were infected with L. major or L. tropica, and disease evolution and DTH responses were determined. The results show that the primary L. major infection can exacerbate the secondary L. major infection and is associated with DTH response. Higher doses of the primary L. major infection result in more disease exacerbation of the secondary L. major infection as well as higher DTH response. L. tropica infection induces lower DTH responses than L. major. We have previously reported that the primary L. tropica infection induces partial protection against the secondary L. major infection in BALB/c mice. Induction of lower DTH response by L. tropica suggests that the protection induced against L. major by prior L. tropica infection may be due to suppression of DTH response.

• Journal of the Korean Statistical Society
• /
• 제36권1호
• /
• pp.129-148
• /
• 2007

Frailty estimates from the proportional hazards frailty model often lead us to conjecture the heterogeneity in frailty such that the variance of the frailty varies over different covariate groups (e.g. male group versus female group). For such systematic heterogeneity in frailty, we consider a regression model for the variance components in the proportional hazards frailty model, denoted by the MLFM. However, in many cases, the observed data do not show any statistically significant preference between the homogeneous frailty model and the heterogeneous frailty model. In this paper, we propose a Bayesian model averaging procedure with the reversible jump Markov chain Monte Carlo which selects the appropriate model automatically. The resulting regression coefficient estimate ignores the model uncertainty from the frailty distribution in view of Bayesian model averaging (Hoeting et al., 1999). Finally, the proposed model and the estimation procedure are illustrated through the analysis of the kidney infection data in McGilchrist and Aisbett (1991) and a simulation study is implemented.

• Journal of applied mathematics & informatics
• /
• 제7권3호
• /
• pp.925-940
• /
• 2000

The spatial spread of a disease in an SIRS epidemic model with immunity imparted by subclinical infection on a population has been considered. The incidence rate of infection and the rate of immunization are both of nonlinear type. The dynamics of the infectious disease and its endemicity in local and global sense have been investigated.

• Journal of applied mathematics & informatics
• /
• 제28권5_6호
• /
• pp.1089-1099
• /
• 2010

An SIR epidemic model with pulse vaccination and time delay describing infection period is investigated. The global attractiveness of the infection-free periodic solution is discussed, and sufficient condition is obtained for the permanence of the system. Our results indicate that a large vaccination rate or a short period of pulsing leads to the eradication of the disease.