Yongkuk Kim

Actin disruption agents induce phosphorylation of histone H2AX in human breast adenocarcinoma MCF-7 cells

Modified actin dynamics are a unique feature of transformed cancer cells and thereby promising targets for cancer chemotherapy. While latrunculin B (LB) and pectenotoxin-2 (PTX-2), both derived from natural sources, inhibit actin polymerization, jasplakinolide (JSP) prevents actin depolymerization. The purpose of this study was to examine the detailed molecular action of actin disruption inducing apoptosis via double strand breaks (DSBs). Actin disruption induced phosphorylation of H2AX, a well known DSB marker leading to G2 arrest and consequently resulted in apoptosis on MCF-7 cancer cells. Cells impaired by actin disruption activated Erk (extracellular signal-related kinase) and p53 protein was involved in DNA damage responses, but did not change the levels of p21Cip1/WAF1 protein in MCF-7 cells. To overcome the DSBs by actin disruption, MCF-7 cells set the repair system through the homologous recombination (HR) pathway. These results indicate that actin is involved in the signaling inducing DSBs and HR repair as well as G2 cell cycle arrest in human cancer. Therefore, the results suggest that actin disruption might be a potential candidate for developing anti-cancer therapies in human breast cancer.

Optimal Control Strategy of Plasmodium vivax Malaria Transmission in Korea

Objective To investigate the optimal control strategy for Plasmodium vivax malaria transmission in Korea. Methods A Plasmodium vivax malaria transmission model with optimal control terms using a deterministic system of differential equations is presented, and analyzed mathematically and numerically. Results If the cost of reducing the reproduction rate of the mosquito population is more than that of prevention measures to minimize mosquito-human contacts, the control of mosquito-human contacts needs to be taken for a longer time, comparing the other situations. More knowledge about the actual effectiveness and costs of control intervention measures would give more realistic control strategies. Conclusion Mathematical model and numerical simulations suggest that the use of mosquito-reduction strategies is more effective than personal protection in some cases but not always.

Mathematical Modeling of Vibrio vulnificus Infection in Korea and the Influence of Global Warming

Objectives To investigate the possible link between Vibrio vulnificus population size in seawater and water temperature. Methods We collected incidence and water temperature data in coastal regions of Korea and constructed a mathematical model that consisted of three classes; susceptible fish, infected fish available to humans, and infected humans. Results We developed a mathematical model to connect V. vulnificus incidence with water temperature using estimated bacterial population sizes and actual coastal water temperatures. Conclusion Increased V. vulnificus population sizes in marine environments may increase the risk of infection in people who eat at coastal restaurants in Korea. Furthermore, we estimated the near-future number of infected patients using our model, which will help to establish a public-health policy to reduce the disease burden.

A note on obesity as epidemic in Korea.

Objective To analyze the incidence of obesity in adults aged 19–59 years in Korea and predict its trend in the future. Methods We considered a two-compartmental deterministic mathematical model Susceptible-Infected-Susceptible (SIS), a system of difference equations, to predict the evolution of obesity in the population and to propose strategies to reduce its incidence. Results The prevention strategy on normal-weight individuals produced a greater improvement than that produced by treatment strategies. Conclusions Mathematical model sensitivity analysis suggests that obesity prevention strategies are more effective than obesity treatment strategies in controlling the increase of adult obesity in Korea.

Connected Sums of 4-Manifolds as Codimension-k Fibrators

The main result provides mild conditions under which a closed, orientable, PL 4-manifold

Light-induced hydrogen and oxygen generation from water

N = N_1\,\#\,N_2

A model for the transmission dynamics of Orientia tsutsugamushi among its natural reservoirs

with

The effect of public health interventions on the spread of influenza among cities

\pi_1(N_e)

Actin disruption inhibits hypoxia inducible factor-1α expression via inactivity of Mdm2-mediated p70S6K

residually finite (

Optimal Implementation of Intervention to Control the Self-harm Epidemic.

e=1,2