• Progress in Medical Physics
• /
• v.20 no.4
• /
• pp.216-224
• /
• 2009

$^{131}I$ is a radiological isotope being used widely for treatment of cancer as emitting gamma-ray and it is also applied to estimate the function of thyroid for its accumulation in thyroid. However, $^{131}I$ is more difficult to quantitate comapred to $^{99m}Tc$, because $^{131}I$ has multiple energy gamma-ray emissions compared to $^{99m}Tc$ which is a mono energetic gamma-ray source. Especially, scattered ray and septal penetration resulted by high energy gamma ray have a bad influence upon nuclear medicine image. The purpose of this study was to estimate scatter components depending on the different source locations within a phantom using Monte Carlo simulation (GATE). The simulation results were validated by comparing with the results of real experiments. Dual-head gamma camera (ECAM, Chicago, Illinois Siemens) with high energy, general-purpose, and parallel hole collimators (hole radius: 0.17 cm, septal thickness: 0.2 cm, length: 5.08 cm) was used in this experiment. The NaI crystal is $44.5{\times}59.1\;cm$ in height and width and 0.95 cm in thickness. The diameter and height of PMMA phantom were 16 cm and 15 cm, respectively. The images were acquired at 5 different locations of $^{131}I$ point source within the phantom and the images of $^{99m}Tc$ were also acquired for comparison purpose with low energy source. The simulation results indicated that the scattering was influenced by the location of source within a phantom. The scattering effects showed the same tendency in both simulation and actual experiment, and the results showed that the simulation was very adequate for further studies. The results supported that the simulation techniques may be used to generalize the scattering effects as a function of a point source location within a phantom.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.1
• /
• pp.38-44
• /
• 2005

In addition to the variation in nitrate accumulation of vegetables due to environmental conditions, there is also a distinct genetic variation. The variation of nitrate accumulation in some cultivars of lettuce and spinach commonly cultivated in Korea was investigated. Ten cultivars for both lettuce and spinach were grown in plastic containers filled with a 1:1 mixture of perlite and vermiculite with application of Hoagland No. 2 nutrient solution of high nitrate content (17.3 mM N) in a greenhouse condition. Plants were harvested four weeks after transplanting four-leaf stage seedlings. Plant growth was measured by fresh and dry matter of shoot, and contents of nitrate and other inorganic ions and organic solutes including sugar, amino acids and organic acids were measured. Large and significant genotypical variations in the nitrate content of the plants were found for both lettuce and spinach, and high negative correlations between nitrate content and fresh or dry weight were found in lettuce and spinach. Variation in nitrate accumulation of lettuce and spinach cultivars was not directly related to the differences in contents of organic and inorganic solutes, and this result indicates that photosynthesis and osmotic regulation are not directly related with the nitrate accumulation. Considering the correlations between nitrate content and plant growth of this study, it can be simply suggested that different cultivars of lettuce and spinach have their own inherited growth and physiological characteristics and also optimum nitrogen level required for the growth. Therefore when available nitrogen in root media is higher than the optimum level required for the inherited growth potential, some of the excess nitrate supplied can be accumulated in plants.

• Korean Journal of Animal Reproduction
• /
• v.24 no.2
• /
• pp.125-142
• /
• 2000

13). Analysis of a purified preparation of eCG revealed that its $\beta$ -subunit consists of 149 amino acids, which was confirmed by the molecular cloning of its cDNA. There seem to be at least four to six, or even as many as 11, O-glycosylation sites on the extended C-tenninal region of the eCG $\beta$-subunit. Interestingly, eCG is a unique member of this family, as it appear to be a single molecule that possesses both LH- and FSH-like activities. Using the cDNA prepared from mRNA extracted from equine placental and pituitary tissues, we cloned the cDNA of eCG $\alpha$- and $\beta$ -subunits and eFSH $\beta$ -subunit. The mRNA expression of each subunit seems to be independently regulated, which may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. Thus, eCG is a distinct molecule from the view points of its biological function and glycoresidue structures. Recombinant eCGs including the mutants which lack oligosaccharides will be useful tools for analyzing the structure-function relationships of gonadotropins in the horse as well as other species. Similar experiments will also clarify the proposed structure and biological functions for the glycoprotein hormones. These experimental are now possible, and hopefully a resolution of the existing controversy will be forthcoming in the near future.

• The Korean Journal of Pharmacology
• /
• v.28 no.1
• /
• pp.61-74
• /
• 1992

Influence of the blockade of the three major pressor systems-sympathetic nervous system (SNS), renin-angiotensin system (RAS) and vasopressin system-on the pressor responsiveness to norepinephrine (NE), angiotensin II (AII), and vasopressin (VP) as well as on basal blood pressure (BP) levels was investigated in urethane-anesthetized rabbits. To block the SNS and RAS, chlorisondamine (CS) and pirenzepine (PZ), sympathetic ganglionic blockers, and enalapril (ENAL), an inhibitor of angiotensin converting enzyme, respectively were used. And for suppressing the VP system bremazocine (BREM), a kappa opiate receptor agonist shown to suppress plasma levels of VP, was employed. Each of CS (0.4 mg/kg), ENAL (2 mg/kg), and BREM (0.25 mg/kg) produced almost same levels of steady hypotensive state. The hypotensive effect of BREM was significantly attenuated by desmopressin, a synthetic VP-like analogue, suggesting the hypotension being at least in part due to suppression of plasma levels of VP. CS, ENAL and BREM elicited further fall of the BP which had been lowered by ENAL or BREM, CS or BREM, and CS or ENAL, respectively. The hypotension produced by both CS and PZ together with either of ENAL or BREM was more marked than that produced by the three drugs other than CS. CS potentiated the pressor response not only to NE but to AII and VP. The pressor effect of AII was increased by ENAL and BREM, too. The pressor response to VP was also enhanced by BREM. Blockade of ${\alpha}-adrenergic$ receptors with phentolamine or phenoxybenzamine potentiated the pressor response to AII and that to VP. The results on basal BP levels indicate that the three major pressor systems are all participating in control of BP, but SNS has the greatest potential for supporting BP. The finding that blockade of one of the pressor systems induced enhanced pressor responsiveness to the pressor hormone of that particular system as well as to the pressor hormone(s) of the other systems(s) provides evidence for important interactions among the three major pressor systems.

• KSBB Journal
• /
• v.22 no.5
• /
• pp.288-296
• /
• 2007

Monascus pilosus (KCCM 60160) in submerged culture was optimized based on culture medium and fermentation conditions. Monacolin-K (Iovastatin), one of the cholesterol lowing-agent which was produced by Monascus pilosus may maintain a healthy lipid level by inhibiting the biosynthesis of cholesterol. Plackett-Burman design and response surface method were employed to study the culture medium for the desirable monacolin-K production. As a result of experimental designs, optimized production medium components and concentrations (g/L) were determined on soluble starch 96, malt extract 44.5, beef extract 30.23, yeast extract 15, $(NH_4)_2SO_4$ 4.03, $Na_2HPO_4{\cdot}12H_2O$ 0.5, L-Histidine 3.0, $KHSO_4$ 1.0, respectively. Monacolin-K production was improved about 3 times in comparison with shake flask fermentation of the basic production medium. The effect of agitation speed (300, 350, 400 and 450 rpm) on the monacolin-K production were also observed in a batch fermenter. Maximum monacolin-K production with the basic production medium was 68 mg/L when agitation speed was 500 rpm. And it was found that all spherical pellets (average diameter of $1.0{\sim}1.5mm$) were dominant during fermentation. Based on the results, the maximum production of 185 mg/L of monacolin-K with the optimized production medium was obtained at pH (controlled) 6.5, agitation rate 400 rpm, aeration rate 1 vvm, and inoculum size 3%.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.1
• /
• pp.15-24
• /
• 2003

The purpose of this study is to investigate the sterilization effect of Er:YAG laser against the intraoral acid producing bacterium, S. mutans, by irradiating the culture solution containing S. mutans KCTC 3065 with Er:YAG laser having a $650{\mu}m$ diameter beam through the non-contact method. We obtained the following results after examining the temperature changes of the culture solution, numbers of bacterial colonies, and acid-producing ability and attaching ability on teeth by measuring the amount of extracellular polysaccharide produced by S. mutans. The number of bacterial colony was decreased in $10{\mu}l$ culture solution irradiated with laser in overall compared to the control solution. The number decreased as the irradiation intensity and pulse repetition rate were larger and as the exposure time was increased. However, it did not change significantly in $100{\mu}l$ culture solution compared to the control solution. Although the acid-producing ability of S. mutans was inhibited for a certain duration after laser irradiation in 10r1 bacterial culture solution, it did not change in $100{\mu}m$ solution compared with the control solution. The amount of extracellular polysaccharide synthesized by S. mutans was partially decreased through laser irradiation in $10{\mu}m$ culture solution but did not change in $100{\mu}m$ culture solution. Based on these findings, we concluded that Er:YAG laser has an sterilization effect on S. mutans in which we presume that the mechanism is through the heat effect rather than the mechanical effect from development of ultrasound.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.11
• /
• pp.1415-1421
• /
• 2008

Preventive effects of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), an active compound in Korean cabbage kimchi with anti-atherogenic effects, on the accumulation of lipids in the vital organs of $apoE^{(-/-)}$ mice fed atherogenic diet (AD) were studied. Each group of 10 mice was fed AD for 8 weeks with intraperitoneal injection of either HDMPPA (1 mg HDMPPA/100 g BW/day) or phosphate buffered saline as a vehicle. The organs used for this study were liver, kidney, spleen, lung, testis, and brain. Total cholesterol (TC) concentration of lung was the highest followed by spleen and brain. TC level for the liver was the lowest. In contrast to the results of TC, triglyceride (TG) concentration in the liver was the highest followed by kidney and testis. $ApoE^{(-/-)}$ mice did not have any problem uptaking chylomicron remnant by the liver which carries an extra TG after delivering it to the adipose tissue. HDMPPA retarded TC and TG accumulations in the vital organs. Thiobarbituric acid reactive substances (TBARS) in the brain and spleen were the highest and that in the testis were the lowest. Poly-unsaturated fatty acids in the brain and activated peroxisome in the spleen might be responsible for high TBARS levels in these organs. The greatest antioxidant effect of HDMPPA against lipid peroxidation was observed in the spleen, showing 21.47% decrease. The most noticeable effect of HDMPPA was observed in glutathione (GSH) level. GSH levels of six organs in the HDMPPA group were significantly higher than those of the control group. GSH-peroxidase activity was negatively related to GSH level of the organs except liver and spleen. In conclusion, HDMPPA from Korean cabbage kimchi inhibits the lipid accumulation as well as increases the antioxidant status in the vital organs of $apoE^{(-/-)}$ mice fed an atherogenic diet.

• Journal of Mushroom
• /
• v.11 no.2
• /
• pp.99-106
• /
• 2013

This study was initiated to investigate the skin whitening activities of methanol extracts from fruiting bodies of I. obliquus. The total polyphenols and flavonoids contents of I. obliquus methanol extracts were 31.85 mg/g and 28.33 mg/g, respectively. The methanol extract of the mushroom treated on B16/F10 melanoma and NIH3T3 cell lines did not show cytotoxic activity. 2,2-diphenyl-1-picrylhydrazyl(DPPH) free radical scavenging activity and chelating activity on ferrous ions of I. obliquus methanol extract were lower than those of positive control, tocopherol and BHT. The tyrosinase and L-DOPA inhibitory activities of the extract were lower than those of positive control, kojic acid and ascorbic acid. The tyrosinase and melanin synthesis inhibitory activities of the melanoma cells treated with the extract were comparable with positive control, arbutin. The experimental results suggested that methanol extract of I. obliquus contained inhibitory activities of tyrosinase and melanin synthesis in the B16/F10 melanoma cells by dose dependent manner. High ultra-violet absorption spectra in the range of 280-350 nm showed that I. obliquus extract could protect skin from UV radiation damage. Therefore, fruiting bodies of I. obliquus can be used for developing skin whitening, anti-UV and skin care agents.

• Journal of Dairy Science and Biotechnology
• /
• v.34 no.1
• /
• pp.21-35
• /
• 2016

Recently, there has been a rapid increase in the sale and purchase of an array of organic products. In particular, organic milk has grown in popularity. This growth could lead to expensive, premium retail prices for various organic cow's milk products. In fact, most consumers believe that (1) dairy farming to produce organic milk is beneficial for human health and (2) organic milk products are made without the use of various antibiotics, synthetic chemicals, genetic modification, extra hormones, and so on. Several factors, including breed, diet, and stage of lactation, are known to influence the composition of milk. Therefore, this review (1) presents a research outline to compare organic and conventional milk and (2) provides a summary of individual elements that affect the composition of milk.

• Journal of Life Science
• /
• v.27 no.11
• /
• pp.1245-1255
• /
• 2017

Most cancer cells produce ATP predominantly through glycolysis instead of through mitochondrial oxidative phosphorylation, even in the presence of oxygen. The phenomenon is termed the Warburg effect, or the glycolytic switch, and it is thought to increase the availability of biosynthetic precursors for cell proliferation. EMTs have critical roles in the initiation of the invasion and metastasis of cancer cells. The glycolytic switch and EMT are important for tumor development and progression; however, their correlation with tumor progression is largely unknown. The Snail transcription factor is a major factor involved in EMT. The Snail expression is regulated by distal-less homeobox 2 (Dlx-2), a homeodomain transcription factor that is involved in embryonic and tumor development. The Dlx-2/Snail cascade is involved in Wnt-induced EMTs and the glycolytic switch. This study showed that in response to Wnt signaling, the Dlx-2/Snail cascade induces the expression of PFKFB2, which is a glycolytic enzyme that synthesizes and degrades fructose 2, 6-bisphosphate (F2,6BP). It also showed that PFKFB2 shRNA prevents Wnt-induced EMTs in the breast-tumor cell line MCF-7. The prevention indicated that glycolysis is linked to Wnt-induced EMT. Additionally, this study showed PFKFB2 shRNA suppresses in vivo tumor metastasis and growth. Finally, it showed the PFKFB2 expression is higher in breast, colon and ovarian cancer tissues than in matched normal tissues regardless of the cancers' stages. The results demonstrated that PFKFB2 is an important regulator of EMTs and metastases induced by the Wnt, Dlx-2 and Snail factors.