• The Korean Journal of Nuclear Medicine
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• v.36 no.3
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• pp.166-176
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• 2002

Purpose: The purpose of this study is to investigate the effects of visual activation and quantitative analysis of regional cerebral blood flow. Visual activation was known to increase regional cerebral blood flow in the visual cortex in occipital lobe. We evaluated that change in the distribution of $^{99m}Tc-HMPAO$ (Hexamethyl propylene amine oxime) to reflect in regional cerebral blood flow. Materials and Methods: The six volunteers were injected with 925 MBq (mean ages: 26.75 years, n=6, 3men, 3women) underwent MRI and $^{99m}Tc-HMPAO$ SPECT during a rest state with closed eyes and visual stimulated with 8 Hz LED. We delineate the legion of interest and calculated the mean count per voxel in each of the fifteen slices to quantitative analysis. The ROI to whole brain ratio and regional index was calculated pixel to pixel subtraction visual non-activation image from visual activation image and constructed brain map using a statistical parameter map (SPM99). Results: The mean regional cerebral blood flow was increased due to visual stimulation. The increase rate of the mean regional cerebral blood flow which of the activation region in primary visual cortex of occipital lobe was $32.50{\pm}5.67%$. The significant activation sites using a statistical parameter of brain constructed a rendering image and image fusion with SPECT and MRI. Conclusion: Visual activation was revealed significant increase through quantitative analysis in visual cortex. Activation region was certified in Talairach coordinate and primary visual cortex (Ba17),visual association area (Ba18,19) of Brodmann.

• Progress in Medical Physics
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• v.17 no.2
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• pp.89-95
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• 2006

The purpose of this study was to evaluate the radiation doses during CT transmission scan by changing tube voltage and tube current, and to estimate the radiation dose during our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan. Radiation doses were evaluated for Philips GEMINI 16 slices PET/CT system. Radiation dose was measured with standard CTDI head and body phantoms in a variety of CT tube voltage and tube current. A pencil ionization chamber with an active length of 100 mm and electrometer were used for radiation dose measurement. The measurement is carried out at the free-in-air, at the center, and at the periphery. The averaged absorbed dose was calculated by the weighted CTDI ($CTDI_w=1/3CTDI_{100,c}+2/3CTDI_{100,p}$) and then equivalent dose were calculated with $CTDI_w$. Specific organ dose was measured with our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan using Alderson phantom and TLDs. The TLDs used for measurements were selected for an accuracy of ${\pm}5%$ and calibrated in 10 MeV X-ray radiation field. The organ or tissue was selected by the recommendations of ICRP 60. The radiation dose during CT scan is affected by the tube voltage and the tube current. The effective dose for $^{137}Cs$ transmission scan and high qualify CT scan are 0.14 mSv and 29.49 mSv, respectively. Radiation dose during transmission scan in the PET/CT system can measure using CTDI phantom with ionization chamber and anthropomorphic phantom with TLDs. further study need to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with same image qualify.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.118-127
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• 2013

In this study, Seongbuk-dong historical & cultural resources of the surrounding landscape were analyzed by the visual characteristics of the landscape adjective analysis. Research was investigate to the relationship between visual characteristics and preferences and Research in the following way. Selected historical and cultural resources in the surrounding area are located in Seongbuk-dong 30 slices the survey was conducted. Landscape preference factors to identify the scale of 16 adjectives and then factor analysis was conducted. Lastly, Analysis of variance and regression analysis were conducted in order to determine the impact of the last image factors on visual preferences. Firstly, The results can be summarized as follows. Officer for 30 pictures appear in Seongbuk-dong in the historical and cultural resources, and distributed around the target preference for the 16 adjectives analysis yielded an average result of overall preference were analyzed and that is a 3.72 average. In these photos, VP8, VP9, VP10, VP12, VP15; 4.5 points more than one order higher. The reason is limit of altitude by the Seoul landscape plan for the historical and cultural resources around. It also judged important reason that history and Culture are in harmony with the surrounding cultural property in the conservation area. Secondly, Important factors are factor 1(aesthetic factors), factor 2(cultural factors), factor 3(physical factors) and three factors could be identified. Results of the analysis of variance and regression analysis about factors for visual preference and image shows value of psychological factor is most significant to explain for nearby history &cultural resources of Seongbuk-dong of scenery around. As a result, the state can not view historical and cultural resources for analysis will be located in a residential area near the historical and cultural resources for aesthetic factors. Third, the negative side of the argument is a residential area which is not arranged surrounding landscape maintenance of historical and cultural resources has emerged. Historical and cultural resources in harmony with the phenomena of the physical, cultural, and aesthetic characteristics of the three areas is a positive factor in the high incidence. Factors from that are expressed in this study by analyzing multi-dimensional analysis to derive a factor to be considered important in the management of historical and cultural resources, landscape around is required.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1551-1558
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• 2002

Purpose : Loss of hippocampal interneurons in dentate gyrus has been reported in patients with severe temporal lobe epilepsy and in animals treated with kainic acid(KA). Interneurons contain $Ca^{2+}$- binding protein parvalbumin(PV). The effects of kainic acid on parvalbumin-immunoreactive (PV-IR) interneurons in dentate gyrus were investigated in organotypic hippocampal slice cultures. Methods : Cultured hippocampal slices from postnatal day nine C57/BL6 mice were exposed to $10{\mu}M$ KA, and were observed at 0, 8, 24, 48, 72 hours after a one hour KA exposure. Neuronal injury was determined by morphologic changes of PV-IR interneuron in dentate gyrus. Results : Transient(1 hour) exposure of hippocampal explant cultures to KA produced marked varicosities in dendrites of PV-IR interneuron in dentate gyrus and the shaft of interbeaded dendrite is often much thinner than those in control. The presence of varicosities in dendrites was reversible with KA washout. The dendrites of KA treated explants were no longer beaded at 8, 24, 48 and 72 hours after KA exposure. The number of cells in PV-IR interneurons in dentate gyrus was decreased at 0, 8 hours after exposure. But there was no significant difference in 24, 48 and 72 hours recovery group compared with control group. Conclusion : The results suggested that loss of PV-IR interneurons in dentate gyrus is transient, and is not accompanied by PV-IR interneuronal cell death.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.383-388
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• 2010

Identification of natural compounds that can prevent the development of obesity in vivo is time consuming and expensive. We have used in vitro systems derived from pig adipose tissue to screen simple aqueous or ethanolic extracts of Korean medicinal herbs (KMH) for their anti-adipogenic potential. A total of 183 extracts were tested for their actions in lipogenesis of pig adipose tissue and differentiation of pig preadipocytes. Ethanol extracts were prepared from 72 and aqueous extracts were prepared from 111 medicinal herbs. Both an ethanolic and an aqueous extract were prepared from 65 of these. Thirteen extracts substantially altered rates of lipogenesis in vitro. The effects of KMH on lipogenesis of pig adipose tissue are as follows. Elevens reduced lipogenesis to rates that were more than 40% lower than control and four of these reduced rates of lipogenesis by more than 70%. The most potent anti-lipogenic extracts were those obtained in ethanol from Iridaceae and from Sophora flavescens AIT as well as both the aqueous and ethanolic extracts from Lysimachia vulgaris L. Two extracts, those prepared in water from Caesalpiniae lignum and from Phellodendri cortex, were found to promote rates of lipogenesis in vitro. The effects of KMH on differentiation of pig preadoipocytes are as follows. Twentyeight extracts altered the rates of differentiation of cultured porcine preadipocytes. Sixteen increased and twelve reduced the rates of differentiation of preadipocytes. Extracts prepared in ethanol from Moutan radicis cortex and from Ostericum koreanum and those prepared in water from Angelicae gigantis radix, from Inula henenium L and from Magnolia flos doubled the rate of differentiation of cultured porcine preadipocytes. Ten extracts reduced the in vitro rate of differentiation of porcine preadipocytes by more than 35%. These were the ethanolic extracts from Glycyrrizae radix, Nepetae spica and from Polygala myrtifolia and the aqueous extracts from Amaranthaceae, Asparagus cochinchinesis, Atractylodis rhizoma alba, Citrus junos TANAKA, Cyperus rotundus, Epimedium grandiflorum and from Moutan radicis cortex. Only the ethanolic extract from Polygala myrtifolia was able to both reduce lipogenesis in adipose tissue slices and retard differentiation of cultured preadipocytes. The results of our study will provide meaningful information to identify medicinal herbs which would reduce fat deposition in livestocks and humans.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.1-11
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• 1996

Since it has been reported that the depolarization-induced norepinephrine (NE) release is inhibited by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus, a large body of experimental data on the post-receptor mechanism of this process has been accumulated. But, the post-receptor mechanism of presynaptic $A_1-adenosine$ receptor on the NE release has not been clearly elucidated yet. Therefore, it was attempted to clarify the post-receptor mechanisms of the $A_1-adenosine$ receptor-mediated control of NE release in this study. Slices from rat hippocampus were equilibrated with $^3H-norepinephrine$ and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 $Vcm^{-1}$, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Adenosine, in concentrations ranging from $1{\sim}30{\mu}M$, decreased the NE release in a dose-dependent manner, without affecting the basal rate of release. The adenosine effects were significantly inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, $2{\mu}M$), a selective $A_1-receptor$ antagonist. The responses to N-ethylmaleimide (NEM, 10 & $30{\mu}M$), a SH-alkylating agent of G-protein, were characterized by increments of the evoked NE-release and the basal release, and the adenosine effects were completely abolished by NEM pretreatment. $4{\beta}-Phorbol$ 12,13-dibutyrate (PDB, $1{\mu}M$), a specific protein kinase C (PKC) activator, increased the evoked NE release, whereas polymyxin B sulfate (PMB,0.1 mg), a PKC inhibitor, decreased the release, and the adenosine effects were inhibited by these agents. Nifedipine $(1{\mu}M)$, a $Ca^{2+}-channel$ blocker of dihydropyridine analogue, did not affect the adenosine effect. Tetraethylammonium (TEA, 3 mM) increased the evoked NE release, and inhibited the adenosine effects, but glibenclamide, a ATP dependent $K^+-channel$ blocker, did not. Finally, 8-bromo cyclic AMP (100 & $300{\mu}M$), a membrane-permeable analogue of cAMP, did not alter the NE release, but adenosine effects were inhibited by pretreatment with 8br-cAMP. These results suggest that the decrement of the evoked NE-release by $A_1-adenosine$ receptor is mediated by the C-protein, which is coupled to protein kinase C, adenylate cyclase system and TEA sensitive $K^+-channel$, and that nifedipine-sensitive $Ca^{2+}-channel$ and glibenclamide-sensitive $K^+-channel$ are not involved in this process.

• Journal of Veterinary Clinics
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• v.27 no.3
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• pp.273-283
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• 2010

The objective of this study was to measure densities in various areas of the normal canine lung with computed tomography (CT) depending on influences of gravity and the degree of lung inflation and to determine optimal positions and positive end expiratory pressure of canine lung for CT scanning. In each eight normal Beagle and Shihtzu dogs, a respiratory breathhold maneuver without spontaenous breathing at different positive end expiratory pressure (PEEP) of 0 mmHg, 10 mmHg and 20 mmHg was applied with the position of right and left lateral recumbency, sternal recumbency, and dorsal recumbency and spiral-CT scans of the total lung were acquired. Slices were selected at three levels through the apex, middle and basal lung at the aortic arch, carina and just above the diaphragm and lung density was measured in the dorsal, ventral, and lateral portions of the peripheral lung field. Lung density in dependent areas was higher than in nondependent areas (p < 0.05) regardless of species, positions, anatomic locations at the PEEP of 0 mmHg and 10 mmHg. However, no significant difference of lung density was found at PEEP of 20 mmHg in both species except the dorsal recumbency in Shihtzu dogs. This density gradient in the dependent areas is strongly influenced by PEEP (p < 0.05). In the four positions on the CT gantry, the lung density at the dependent and nondependent location of the lung was greater at the aortic arch than at the base (p < 0.05). Lung density decreased on identical location according to increase of PEEP (p < 0.05). There was no significant difference between right and left lung density at sternal and dorsal recumbency and no significant difference of the dorsal, ventral, and lateral portions of lung density at the right and left recumbency under identical pressure. It is implied that during chest CT scan with 20 mmHg of positive end expiratory pressure with right or left lateral recumbency, canine lung density do not influenced by gravity or anatomic location.

• The Korean Journal of Nuclear Medicine
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• v.25 no.1
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• pp.6-16
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• 1991

Regional cerebral blood flow (rCBF) was evaluated in 12 children ranging in age from 2.7 to 10.0 yr using $^{99m}Tc-HMPAO$ SPECT. For quantitative analysis, 13 pairs of homologous regions of interest (ROIs) were created on three attenuation-corrected 18.8 mm thick transverse slices matching the cerebral cortical regions, deep gray matter, cerebellar hemisphere, and vascular territories, and the semiquantitative indices including "right to left ratio" [(mean count/voxel of homologous right ROI) / (mean count/voxel of homologous left ROI)] and "regional index"(RI) [(mean count/voxel of a ROI)/ (mean count/voxel of all ROIs of each hemisphere)] were calculated. Mean values of right to left ratios of homologous regions ranged from 0.984 to 1.028 in children under 5 yr (group 1) and from 0.982 to 1.012 in children between 5 and 10 yr (group 2), and the mean $value{\pm}2S.D.$ for each region did not exceed 11% and 12% in group 1 and group 2, respectively. There were no statistically significant differences between the RIs of the homologous right and left regions. Significant differences of RIs were found both between vascular regions (p<0.0005 for goup 1, and p=0.0001 for goup 2) and between regions of cerebral cortices (p<0.0005 for group 1, and p<0.005 for group 2) with a relatively high value in the occipital cortex and the lower values in the cerebellum and deep gray matter among the regions of cerebral cortices in both groups. There were no significant differences between the RIs of corresponding regions of group 1 and group 2, except a significantly higher value of right deep gray matter in group 2 than in group 1(p=0.0301). The RIs of the superior frontal cortex and deep gray matter showed to be positively correlated with age (superior frontal cortex; right: rs=0.5254, p=0.0814, left : rs=0.5919, p=0.0496/deep gray matter; right: rs=0.8246, p=0.0062, left: rs=0.6266, p=0.0377). The results suggest that the rCBF pattern of children approaches that of adults in an accipito-rostral direction. This time course of rCBF changes is in agreement with behavioral, neurophysiological, and anatomical alterations known to occur in the developing brain.

• The Korean Journal of Nuclear Medicine
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• v.32 no.2
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• pp.143-150
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• 1998

Purpose: T1-201 SPECT has been used in differentiating benign and malignant pulmonary lesions. While its sensitivity may be high, the specificity and predictive values are reported to be variable depending on the type of benign lung lesion. The purpose of this study was to prospectively assess the efficacy of T1-201 SPECT for differentiating benign and malignant single pulmonary lesion in a population with a high prevalence of benign pulmonary lesion, especially, tuberculosis. Materials and Methods: One-hundred thirty-three patients, having 89 malignant and 44 benign lesions(23 active tuberculosis, 5 inactive tuberculosis, 3 aspergil-loma, 3 focal pneumonia, 2 thymoma, and 8 others), were imaged using a dual-headed system at 15 minute(early) and 3 hour (delayed) following administration of 111MBq T1-201. The images were read visually and lesion-to-background ratios(L/B) were obtained from transverse tomographic slices. Retention index was expressed as [(delayed L/B- early L/B) $\div$ early L/B]. Results: 82/89(92%) and 83/89(93%) of the malignant lesions were visually positive on the early and delayed images, and 27/44(61%) and 26/44(59%) of the benign lesions were also visually positive on both images. Although a statistically significant difference was found between the mean L/B's of the malignant and benign lesions, L/B was not useful for differentiating the two due to a large overlap. There was no difference in retention indices. Conclusion: Despite of its high sensitivity, the specificity of T1-201 SPECT was unacceptably low in patients with active benign lesions. The positive and negative predictive values for lung cancer in a population with a high prevalence of the benign single pulmonary lesion was only marginal.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.41-47
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• 1995

Tc-99m-MIBI(Sestamibi) myocardial SPECT along with T1-201 tomographic imaging has demonstrated wide application and high image qualify sufficient for the diagnosis of myocardial perfusion defect, which consequently reflects regional myocardial blood flow, The qualitative values of myocardial SPECT with Tc-99m-MIBI as well as the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection(FBP) is the common standard for reconstruction rather than the complicated and time-consuming arithmetic methods. In FBP it Is known that the distribution of radioactivity in reconstructed transverse slices varies with the selected filter parameters such as cutoff frequencies and order(Butterworth case). The cutoff frequencies basically remove and decrease the true radioactive distribution and alter the pixel counts, which lead to underestimation of true counts in specific myocardial regions. In this study, we have investigated the effect of cutoff frequencies of reconstruction filter on the artifactually induced perfusion defects, which are often demonstrated near inferior and/or inferoseptal cardiac walls due to the intense hepatic uptake of Tc-99m-MIBI. A computerized method for identifying the relative degree of artifactual perfusion defect and for comparing those degrees along with the relative amount of hepatic uptake to myocardium was developed and patient images were studied to observe the quantitative degree of underestimation of myocardial perfusion, and to propose some reasonable thresh-old of cutoff frequency in the diagnosis of perfusion defect quantitatively. We concluded that from the quantitative viewpoint cutoff frequencies may be used as high as possible with the sacrifice of homogeneity of image quality, and those frequencies lower than the common 0.3 Nyquist frequency would reveal severe degradation of radio-active distribution near inferior and/or Inferoseptal myocardium when applying Butterworth or low pass filter.