• Journal of Preventive Medicine and Public Health
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• v.35 no.1
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• pp.65-71
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• 2002

Objective : To estimate the status of HIV infection and AIDS incidence using a back-calculation model in Korea. Methods : Back-calculation is a method for estimating the past infection rate using AIDS incidence data. The method has been useful for obtaining short-term projections of AIDS incidence and estimating previous HIV prevalence. If the density of the incubation periods is known, together with the AIDS incidence, we can estimate historical HIV infections and forecast AIDS incidence in any time period up to time t. In this paper, we estimated the number of HIV infections and AIDS incidence according to the distribution of various incubation periods Results : The cumulative numbers of HIV infection from 1991 to 1996 were $708{\sim}1,426$ in Weibull distribution and $918{\sim}1,980$ in Gamma distribution. The projected AIDS incidence in 1997 was $16{\sim}25$ in Weibull distribution and $13{\sim}26$ in Gamma distribution. Conclusions : The estimated cumulative HIV infections from 1991 to 1996 were $1.4{\sim}4.0$ times more than notified cumulative HIV infections. Additionally, the projected AIDS incidence in 1997 was less than the notified AIDS cases. The reason for this underestimation derives from the very low level of HIV prevalence in Korea, further research is required for the distribution of the incubation period of HIV infection in Korea, particularly for the effects of combination treatments.

• Journal of Preventive Medicine and Public Health
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• v.26 no.4 s.44
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• pp.541-550
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• 1993

In order to investigate psychological and behavioral characteristics of homosexuals and to present evidence that homosexuals are in danger of HIV infection in Korea, this study was done by self-administered questionnaire and then direct interview with the 28 (35%) HIV infected homosexual/bisexuals of 79 HIV infected persons reported in 1992. Homosexuals without heterosexual activity were 9 and the others were bisexuals. Sixty-five percent of respondents had a guilty conscience for their homosexual activty. Twenty (71%) were in twenties and 5 (18%) in thirties. Twelve(43%) were detected via health card checking by health office, 21% by blood donation, 18% by hospital visit, and 7% by partner notification. Motivations for homosexual activity were curiosity (36%), temptation or recommendation (14%) and compulsion (11%). Eighteen (72%) never used condom on anal sex. Nine of 26 respondents had experience for anal sex with foreigners. Fourteen (54%) of 26 respondents had history for sexually transmitted diseases. Fighty percent did not have sexual contact after HIV infection and the others usually used condom. It was confirmed that over 57% of the respondents were infected within 1 year before HIV diagnosis and over 82% within 2 years. These data suggest that HTV infection among homosexual group is rapidly spreading.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.539-542
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• 2011

Purpose: Despite the increasing number of patients with HIV (human immunodeficiency virus) infection, surgical experience with these patients remains limited in aesthetic and reconstructive surgery. The authors performed breast reconsruction with free TRAM (Transverse Rectus Abdominis Muculocutaneous) flap in HIV infected patient firstly in Korea. Methods: A 53-years-old female with HIV positive underwent delayed breast reconstruction with free TRAM flap and 6 months lateral nipple reconstruction was performed. All procedures were performed according to the HIV infection control guidelines provided by the Korea Centers for Disease Control and Prevention. Results: There were no complications such as infection, hematoma and flap loss and symmetry of breast was achieved. Conclusion: When the operation is performed in line with the guidelines of HIV infection control, breast reconstruction with free flap is possible and can obtain successful results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.594-599
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• 2016

Infection with HIV (Human immunodeficiency virus), over time, develops into acquired immunodeficiency syndrome (AIDS). The development of non-toxic and effective anti-HIV drugs is one of the most promising strategies for the treatment of AIDS. In this study, we investigated the anti-HIV-1 activity of gelatin hydrolysates from Alaska pollack skin. Gelatin hydrolysates were prepared using four enzymes (alcalase, flavourzyme, neutrase, and pronase E). Among these, the pronase E gelatin hydrolysate was found to inhibit HIV-1 infection in the human T cell-line MT4. It exhibited inhibitory activity on HIV-1_IIIB-induced cell lysis, reverse transcriptase activity, and viral p24 production at noncytotoxic concentrations. Moreover, it decreased the activation of matrix metalloproteinase-2 (MMP-2) in vitro. Because HIV infection-induced activation of MMP-2 can accelerate collagen resolution and collapse of the immune system, pronase E gelatin hydrolysate might prevent the activation of MMP-2 in cells, resulting in collagen stabilization and immune cell homeostasis consistent with anti-HIV activation. These results suggest that pronase E gelatin hydrolysate could potentially be incorporated into a novel therapeutic agent for HIV/AIDS patients.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.950-955
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• 2014

In this paper, we propose a drug treatment protocol for the three state HIV infection model that explicitly includes the concentration of healthy T cells, infected T cells, and HIV. While most of the previous methods are not able to achieve the treatment goal in the presence of modelling errors, the proposed method is designed so as to compensate for the model uncertainties. Based on the Jacobain linearization of nonlinear HIV infection model, disturbance observer(DOB) based control is employed to design the drug treatment for the HIV patients. Computer simulation is carried out for nonlinear model in order to compare the performance of the proposed method with that of the conventional technique. The simulation results show that, in the presence of parameter uncertainties, the substantial improvement in the performance can be achieved by the proposed DOB controller.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.815-822
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• 2001

The aim of this study is to estimate the seroconversion date of the human immunodeficiency virus(HIV) infection for the HIV infected patients in Korea. Data are collected from two cohorts. The first cohort is a group of "seroprevalent" patients who were seropositive and AIDS-free at entry. The other is a group of "seroincident" patients who were initially seronegative but later converted to HIV antibody-positive. The seroconversion dates of the seroincident cohort are available while those of the seroprevalent cohort are not. Estimation of seroconversion date is important because it can be used to calculate the incubation period of AIDS which is defined as the elapsed time between the HIV infection and the development of AIDS. In this paper, a Weibull regression model Is fitted for the seroincident cohort using information about the elapsed time since seroconversion and the CD4$^{+}$ cell count.The seroconversion dates for the seroprevalent cohort are imputed on the basis of the marker of maturity of HIV infection percent of CD4$^{+}$cell count.unt.

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.559-578
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• 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.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.295-304
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• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.10
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• pp.1454-1459
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• 2015

In this paper, a drug treatment protocol is proposed for an HIV infection model that explicitly includes the concentration of healthy T cells, infected T cells, and HIV. Since real parameters of HIV infection model differ from patient to patient, most drug treatment protocols are not able to achieve the treatment goal in the presence of modelling errors. Recently, based on the nonlinear robust control theory, a robust treatment protocol has been proposed that deals with parameter uncertainties. Although the developed scheme is inherently complex, it cannot be applied to the case where all parameters are unknown. In this paper, we propose a new drug treatment protocol that is much simpler than the previous one but can achieve the treatment goal even when all model parameters are unknown. The simulation results verify that the substantial improvement in the performance can be achieved by the proposed scheme.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.555-574
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• 2011

It is well known that the mathematical models provide very important information for the research of human immunodeciency virus type. However, the infection rate of almost all mathematical models is linear. The linearity shows the simple interaction between the T-cells and the viral particles. In this paper, a differential equation model of HIV infection of $CD4^+$ T-cells with Crowley-Martin function response is studied. We prove that if the basic reproduction number $R_0$ < 1, the HIV infection is cleared from the T-cell population and the disease dies out; if $R_0$ > 1, the HIV infection persists in the host. We find that the chronic disease steady state is globally asymptotically stable if $R_0$ > 1. Numerical simulations are presented to illustrate the results.