Sang-Rak Lee

Cytotoxicity of amphotericin B-incorporated polymeric micelles composed of poly(DL-lactide-co-glycolide)/dextran graft copolymer

In this study, we prepared amphotericin B (AmpB)-encapsulated polymeric micelle of poly(DL-lactideco-glycolide) (PLGA) grafted-dextran (DexLG) copolymer for the cytotoxicity test. The average particle size of AmpB-encapsulated DexLG polymeric micelles was around 30∼70 nm and their morphology showed spherical shapes. Since aggregation states of AmpB are related to intrinsic cytotoxicity, prevention of AmpB aggregation in aqueous solution will provide low cytotoxicity and increased antimicrobial activity for the infectious disease. At UV/VIS spectrum measurement, polymeric micelle prepared from methanol/water mixture (method B) showed a monomeric state of AmpB while polymeric micelle prepared from DMSO (method A) showed an aggregated state. During the hemolysis activity test, polymeric micelle from method B showed reduced hemolysis activity compared to AmpB itself and polymeric micelle from method A. These results indicated that AmpB-incorporated polymeric micelle prepared from methanol/water mixture has low cytotoxicity and favorable antimicrobial activity.

Antitumor effect of adriamycin-encapsulated nanoparticles of poly(DL-lactide-co-glycolide)-grafted dextran

In this study, we prepared adriamycin (ADR)-encapsulated core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer and evaluated its antitumor activity in vitro and in vivo. The particle size of ADR-encapsulated DexLG nanoparticles was around 50-200 nm and the morphology was spherical shapes at transmission electron microscopy (TEM) observation. Since reconstitution of lyophilized nanoparticles is essential to practical use in vivo, ADR-encapsulated DexLG nanoparticles were lyophilized and reconstituted them into deionized water. Although reconstitution process caused increase of particle size, drug release behavior of nanoparticles was not significantly changed before and after reconstitution process. The ADR-encapsulated DexLG nanoparticles were less cytotoxic than free ADR plus empty nanoparticles at in vitro, while empty DexLG nanoparticles did not significantly affect cell viability. Even if free ADR plus empty nanoparticles are most effective to inhibit tumor growth at tumor-induced animal model using CT-26 cells, ADR-encapsulated DexLG nanoparticles showed increased survivability of mice. These results indicated that ADR-encapsulated DexLG nanoparticles are promising vehicles for antitumor drug delivery.

Effect of the Climatic Condition on the Growth Characteristic of Domestic Corn Hybrids in Alpine Region

The aim of the present study was to investigate the relationship between climates, growth characteristic and yield of silage corn at Hanwoo Experiment Station, National Institute of Animal Science, Daegwallyeong in Gangwon Province located at altitude of 760 m, from 2009 to 2010. The mean minimum temperature was from seeding to harvest in 2009, in 2010, the mean maximum temperature was , , respectively. The mean temperature was in 2009 and in 2010, respectively. Duration of sunshine was 711.3 hours in 2009 and 663.8 hours in 2010, and precipitation was 893.8 mm in 2009 and 752.1 mm in 2010, respectively. In 2009, for all Kwangpyeongok, Gangdaok, Cheonganok, Cheongsaok, Pyeonganok, the early growth was good with 1.2, while in 2010 the growth for Pyeonganok was good with 1.3 comparing to others, which showed worse growth than in the previous year with 2.4~3.0. There was significant difference in the ear height between 2009 and 2010, showing mean value of 85.8 cm and 105 cm for all the species in 2009 and in 2010, respectively (p

Effects of Fiber Sources on Ruminal pH, Buffering Capacity and Digestibility in Sheep

This study was conducted to study the effect of fiber sources on ruminal pH and buffering capacity and whole digestive tract digestibility with five ruminally fistulated sheep. Evaluated fiber sources were alfalfa hay cube (AHC), corn cob (CC), com silage (CS), cotton seed hull (CSH), peanut hull (PHL), rice straw (RS), and sugarcane bagasse (SCB). Sheep were fed consecutively a diet containing each tested fiber source with a corn-based concentrate diets during each experimental period. Ruminal pH showed no difference among fiber sources except the significantly lower pH at 8h (p

Analysis of the User Requirements for Development of Integrated Livestock Excretion Management System applied with the Ubiquitous Technology

Although the livestock excretion is a significant resource in providing nutrients to the crops as it is recycled, it has been perceived as the cause of environmental pollutions for its inappropriate treatment and quality control issues. The study is aimed to develop an integrated management system for efficient management of livestock excretion using the Ubiquitous technology, and the user requirements are analyzed for development of such system. As the result of analysis on the requirements, it has been proved that such system is perceived to be necessary and the demand for several main functions can be seen as well.

A Study of Ubiquitous-based Stall Management System

It is very important, if necessary, to remotely monitor and control the body conditions and behavior of livestock as well as the environment of stall using ubiquitous ict, in order to improve the health and productivity of livestock. With the aim of developing a stall management system, this study investigated users’ needs, analyzed them to design systems, developed a web-system and an app for stall management, then applied them to a test-bed. The use of the app developed will make it easy for livestock farmers to easily monitor and control environment of stall using their smartphones and allow them to take care of stall more efficiently. (

Effects of Crude Protein Levels on Nitrogen Balance in Adult Jindo Dog

This study was conducted to determine the protein requirement level in adult Jindo dog (Korea Jindo Dog) through nitrogen balance experiments. 12 female dogs aged 36~38 weeks old (for early stage) or aged 45~49 weeks old (for late stage) were fed one of 3 diets containing 17, 19 and 21% of crude protein. Body weight of dogs were measured during the 12 days of feeding trial, and feces and urine were collected last 3 days of the trial period. In early stage of Jindo dog, average daily gain of dogs fed experimental diets containing 17, 19 and 21% of crude protein were 38.33, 16.25 and 12.71g/d, respectively. There was a significant differences between 17 and 21% of crude protein treatments (p<0.05) and calculated retained nitrogen were 0.29, 0.04 and 0.03g/kgBW .75 /d, respectively. In late stage of Jindo dog, average daily gain of dogs fed experimental diets containing 17, 19 and 21% of crude protein were 34.05, 28.71 and -28.28g/d, and calculated retained nitrogen were 0.33, 0.06 and 0.09g/kgBW .75 /d, respectively, and were significantly higher (p<0.05) in dogs fed 21% of crude protein diet than those of other dogs. In early stage and late stage of adult Jindo dog, a calculated linear regression equation for nitrogen intake (x) and nitrogen retention (y) were y = 0.7484x 1.18 (R 2 = 0.9923) and y = 0.88231x 1.0894 (R 2 = 0.9982) and the requirement of crude protein were estimated as 9.85g/kg BW .75 /d and 7.72g/kg BW .75 /d from above equation.

Effects of Protein Levels on Growth and Nitrogen Balance in Growing Jindo Dog

This study was conducted to determine the protein requirement level in growing Jindo dog through nitrogen balance experiment. Twelve female dogs aged 18～20 weeks old were allotted one of 3 dietary treatments containing 21, 23 and 25% of crude protein. Average daily gain of dogs fed experimental diets containing 21, 23 and 25% of crude protein were 65.42, 79.58 and 99.17g/d, respectively, and there was a significant difference between 21 and 25% of crude protein treatments(p