• The Korean Journal of Physiology and Pharmacology
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• 제3권5호
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• pp.529-538
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• 1999

This study was undertaken to examine the effect of ethanol on $Na^+ -dependent$ phosphate $(Na^+-P_i)$ uptake in opossum kidney (OK) cells, an established renal proximal tubular cell line. Ethanol inhibited ^Na^+-dependent$ component of phosphate uptake in a dose-dependent manner with $I_{50}$ of 8.4%, but it did not affect $Na^+-independent$ component. Similarly, ethanol inhibited $Na^+-dependent$ uptakes of glucose and amino acids (AIB, glycine, alanine, and leucine). Microsomal $Na^+-K^+-ATPase$ activity was not significantly altered when cells were treated with 8% ethanol. Kinetic analysis showed that ethanol increased $K_m$ without a change in $V_{max}$ of $Na^+-P_i$ uptake. Inhibitory effect of n-alcohols on $Na^+-P_i$ uptake was dependent on the length of the hydrocarbon chain, and it resulted from the binding of one molecule of alcohol, as indicated by the Hill coefficient (n) of 0.8-1.04. Catalase significantly prevented the inhibition, but superoxide dismutase and hydroxyl radical scavengers did not alter the ethanol effect. A potent antioxidant DPPD and iron chelators did not prevent the inhibition. Pyrazole, an inhibitor of alcohol dehydrogenase, did not attenuate ethanol-induced inhibition of $Na^+-P_i$ uptake, but it prevented ethanol-induced cell death. These results suggest that ethanol may inhibit $Na^+-P_i$ uptake through a direct action on the carrier protein, although the transport system is affected by alterations in the lipid environment of the membrane.

• 대한임상검사과학회지
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• 제41권2호
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• pp.83-92
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• 2009

This study was undertaken to examine the effect of oxidants on membrane transport function in renal epithelial cells. Hydrogen peroxide ($H_2O_2$) was used as a model oxidant and the membrane transport function was evaluated by measuring $Na^+$-dependent phosphate ($Na^+$-Pi) uptake in opossum kidney (OK) cells. $H_2O_2$ inhibited $Na^+$-Pi uptake in a dose-dependent manner. The oxidant also caused loss of cell viability in a dose-dependent fashion. However, the extent of inhibition of the uptake was larger than that in cell viability. $H_2O_2$ inhibited $Na^+$-dependent uptake without any effect on $Na^+$-independent uptake. $H_2O_2$-induced inhibition of $Na^+$-Pi uptake was prevented completely by catalase, dimethylthiourea, and deferoxamine, suggesting involvement of hydroxyl radical generated by an iron-dependent mechanism. In contrast, antioxidants Trolox, N,N'-diphenyl-p-phenylenediamine, and butylated hydroxyanisole did not affect the $H_2O_2$ inhibition. Kinetic analysis indicated that $H_2O_2$ decreased Vmax of $Na^+$-Pi uptake with no change in the Km value. Phosphonoformic acid binding assay did not show any difference between control and $H_2O_2$-treated cells. $H_2O_2$ also did not cause degradation of $Na^+$-Pi transporter protein. Reduction in $Na^+$-Pi uptake by $H_2O_2$ was associated with ATP depletion and direct inhibition of $Na^+$-$K^+$-ATPase activity. These results indicate that the effect of $H_2O_2$ on membrane transport function in OK cells is associated with reduction in functional $Na^+$-pump activity. In addition, the inhibitory effect of $H_2O_2$ was not associated with lipid peroxidation.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8095-8099
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• 2014

Background: Worldwide, over half a million women died of breast cancer in 2011 alone. Mammography screening is associated with a reduction of 20 to 35% in breast cancer mortality. The aim of this study was to determine the awareness and practice of mammography screening and predictors of its uptake in Malaysian women attending a primary care clinic. Materials and Methods: A cross-sectional study was carried out among women aged 40 to 74 years attending a primary care clinic in Selangor, Malaysia. An assisted structured questionnaire included questions on socio-demography, source of information and level of knowledge. An adapted version of the revised Champion Health Belief Model Scale plus other associated factors for mammography screening up-take were also included as part of the questionnaire. Predictors for mammography screening uptake were only determined in those who were aware about mammography screening. Significant predictors were determined by logistic regression. Results: 447 women were recruited for this study; 99.1% of them (n: 411) were aware about breast cancer. Only 50.1% (n: 206) had knowledge about mammography screening. Prevalence of clinical breast-examination (CBE) was 23.3% (n: 104) and mammography screening up-take was 13.2% (n: 59). The predictors for the latter were those who have had clinical breast-examination (aOR=17.58, 95%CI: 7.68-39.82) and those aged between 50 to 59 years (aOR=3.94, 95%CI: 1.61-9.66) as well as those aged 60 years and above (aOR=6.91, 95%CI: 2.28-20.94). Good knowledge and positive beliefs about mammography screening were not associated with mammography screening uptake. Conclusions: Half of our Malaysian women were aware about mammography screening. However, the uptake of mammography was low. Previous CBE and older age were significant predictors of mammography screening uptake. Increasing CBE services may increase compliance with guidelines.

• 한국환경농학회지
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• 제21권1호
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• pp.69-73
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• 2002

질산태 질소의 일중 농도 변화와 단기간의 저온 처리가 질산태 질소의 흡수 및 농도에 미치는 영향을 살펴보고자 상추 (Lactuca sativa L.)를 공시 작물로 하여 온실에서 수경 재배하였다. 질산태 질소의 농도는 엽신에 비하여 주맥에서 일중 지속적으로 2배 이상 높았으며, 질산태 질소의 일중 변화는 14:00까지 지속적으로 감소하여 최저치 (8.7 mg-N/GDW)를 나타낸 후 다시 증가하였다. 질산태 질소의 일중 흡수량은 11:00$\sim$17:00에 평균 4.8 mg-N/GDW-Root/hr로 최대치를 나타내었다. 단기간의 저온 처리는 엽의 질산태 질소의 농도를 14$\sim$18%, 질산태 질소의 흡수량을 50$\sim$55%를 감소시켰다. 이러한 결과는 수확 전 단기간의 저온처리가 상추 잎의 질산태 질소함량을 낮출 수 있는 방법으로 응용될 수 있음을 보여준다.

• 한국토양비료학회지
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• 제48권3호
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• pp.205-212
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• 2015

Farmers with forage barley (Hordeum vulgare L.)-rice (Oryza sativa L.) cropping system at reclaimed tidal lands burn crop residues to facilitate seedbed preparation or remove them for feed stock. This study was conducted to investigate the effect of rice straw amendment and N fertilization on soil properties and N uptake of rice under forage barely-rice cropping system at reclaimed tidal paddy field. Rice straw was applied at the rates of 0, 2.5 and $5.0ton\;ha^{-1}$ and N was fertilized at 0, 100, 200 and $400kg\;ha^{-1}$. Although there was no significant difference in the growth and yield of rice, fresh and dry weight of forage barely increased with increasing the amount of rice straw. The amount of N uptake of rice at harvesting stage was $65.8-69.2kg\;ha^{-1}$ by the amount of rice straw amendment, but there were no significant differences among rice straw amendment levels. After harvesting the rice, the soil salinity decreased with rice straw amendment compared to the control. After forage barely and rice cultivation, soil organic matter contents increased to $2.6-2.8g\;kg^{-1}$ and $3.2-3.5g\;kg^{-1}$, respectively. The amount of N uptake of rice at harvesting stage increased up to $82kg\;ha^{-1}$ in $400kg\;ha^{-1}$ N applied plots which were $37.8kg\;ha^{-1}$ higher than the control. Nitrogen fertilization decreased N recovery efficiency. The highest yield of rice was observed at $244kg\;ha^{-1}$ N fertilization level, but the optimum N level was estimated at $168kg\;ha^{-1}$ in order to keep the protein content of rice under 6.5%. Further researches on N uptake and application of organic matter according to soil salinity will be necessary to increase N use efficiency at reclaimed tidal paddy field.

• 한국작물학회지
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• 제53권1호
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• pp.50-57
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• 2008

월동 후 녹비용 호밀에 시용한 질소가 콩의 질소고정 및 흡수에 미치는 효과를 보기 위하여, 2004년 온실 및 2005년 포장에서 포트시험을 통해 시비질소량별 토양, 호밀 및 콩의 질소회수율을 조사하였다. 1. 2004년 온실폿트 시험에서는 호밀에 시용한 질소비료 량이 증가할수록 호밀지상부가 토양에서보다 질소비료로부터 질소를 흡수하는 비율이 증가하였다. 호밀이 없는 조건에서는 논흙이 밭흙보다 콩의 건물 중 및 질소흡수량이 현저히 증가하였는데, 지력이 높았던 논흙에서는 밭흙에 비해 콩이 질소고정 유래 질소의 비율이 상대적으로 낮아지고 토양유래 질소의 비율이 높았다. 2. 밭흙에서 무녹비와 대비하였을 때 호밀녹비 이용 시의 콩 시비질소회수율은 낮았지만 토양의 시비질소회수율(질소유기화)이 높아 전체회수율은 높았으며, 또 호밀녹비 이용시 콩의 시비질소회수율은 호밀에 대한 질소시용량이 많을수록 증가하였다. 3. 2004년 온실포트 실험에서의 콩의 근류고정유래의 질소비율은 약 $92{\sim}95%$로 2005년 포장포트에서의 $82{\sim}84%$보다 약 10% 정도 높았으며, 콩의 근류고정유래 질소량 및 질소량 분획 추정에서는 2년 모두 Difference method와 $^{15}N$ method간 차이를 보이지 않았다.

• Journal of Pharmaceutical Investigation
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• 제38권4호
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• pp.255-259
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• 2008

The present study aimed to investigate the in-vitro characteristics of N4-amino acid derivatives of cytarabine for the oral delivery of cytarabine. After the synthesis of L-Ile-cytarabine, L-Leu-cytarabine and L-Arg-cytarabine, the gastrointestinal stability of each prodrug was examined using artificial gastric juice and intestinal fluids. The cellular uptake characteristics of prodrugs were also examined in Caco-2 cells. While L-Ile-cytarabine and L-Leu-cytarabine appeared to be stable in all the tested biological media during 4-hr incubation, L-Arg-cytarabine was rapidly disappeared within 5 min. Accordingly, the cellular uptake of L-Ile-cytarabine and L-Leu-cytarabine was significantly higher than that of its parent drug, cytarabine in Caco-2 cells but the cellular uptake of L-Arg-cytarabine was similar to that from its parent drug. The cellular uptake of L-Ile-cytarabine and L-Leu-cytarabine appeared to be saturable as drug concentration increased from 0.4 to 4 mM. Collectively, L-Ile-cytarabine and L-Leu-cytarabine could be promising candidates to improve the oral absorption of cytarabine via a saturable transport pathway.

• ALGAE
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• 제25권1호
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• pp.17-26
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• 2010

The effects of salinity on various ecophysiological parameters of Ulva pertusa such as growth, nutrient uptake, photosynthetic performance and internal nutrient composition were tested. U. pertusa was collected from an eelgrass bed in a semi-protected embayment on the southwest coast of Korea. Under salinity regimes from 5 to 40 psu, the specific growth rates $(\mu)$ of U. pertusa ranged from 0.019 to $0.032\;d^{-1}$. Maximum growth rate was observed at 20 psu, and minimum at 40 psu. This species showed various uptake rates for nitrate and phosphate. Nutrient uptake was noticeably higher at intermediate salinity levels, and lower at both extremes. Salinity significantly influenced chlorophyll-$\alpha$ content and effective quantum yield. Tissue nitrogen content ranged from 1.5 to 2.9% N (dry weight), whereas tissue phosphorus ranged from 0.1 to 0.14% P (dry weight). The N : P ratio in the tissue of U. pertusa was considerably higher, ranging from 30 to 50. Increased growth at lower salinity suggests that the initial growth rate of U. pertusa is greater during the rainy season (i.e., late spring and early summer) than any other season during the year. The appearance of an Ulva bloom in eelgrass beds may be triggered by salinity more than by other environmental factors such as light and temperature.

• 한국환경과학회지
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• 제4권5호
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• pp.141-141
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• 1995

The waste biomass of Sacchromyces uvarum, used in fermentation industries to produce ethanol, were studied for their ability to absorb various heavy metal ions. Heavy metal ions studied in this research were Cd, Co, Cr, Cu, Ni and Pb. The order of the sorption capacity was Pb>Cu>Co=Cr=Cd>Ni. The living Sacchromyces uvarum exhibited higher metal-uptake capacity than the dead Sacchromyces uvarum. After we compare the uptake capacity of the Sacchromyces uvarum for individual metal ions with for a mixture of them, the following was observed: in the mixed heavy metal solution the uptake capacity was decreased than the one heavy metal solution. The selective uptake was observed when all . the heavy metal ions were dissolved in a mixed solution. The adsorption isotherm modelling was decribed with the Langmuir and Freundlich model. The results were in good agreement with the Langmuir model.

• 한국작물학회지
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• 제49권1호
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• pp.1-6
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• 2004

N fertilizer required by rice could be reduced greatly in the rice-barley double cropping system than in the rice single cropping system. This study was conducted to investigate how much of the N fertilizer during the early stage of rice in the rice-barley double cropping system, could be saved compared to that in the rice single cropping system. This experiment was carried out at the paddy field of the National Crop Experiment Station in Suwon, Korea during three years from 1999 to 2001. Amounts of soil mineral nitrogen (SMN) and SPAD values of rice leaf during rice growing season in the rice-barley double cropping system were higher than those in the rice single cropping system under the same amount of N application during two years. Yield and N uptakes of rice at harvesting time were also higher in the rice-barley double cropping system than in the rice single cropping system during two years. Yield and N uptake of rice in the rice single cropping system were decreased when basal N fertilizer was omitted, but those reductions were not found by either omitting basal N fertilizer or omitting N fertilizer at tillering stage in the rice-barley double cropping system during 2000 and 2001. But yield and N uptakes of rice were decreased by 70 kg/10a and 2kgN/10a by the omission of both N application at basal and tillering stages in the rice-barley double cropping system in 2002. It was concluded that N fertilizer as much as tillering N fertilizer could be saved in the rice-barley double cropping system.