• The Korean Journal of Nuclear Medicine
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• 제29권1호
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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.

• The Korean Journal of Nuclear Medicine
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• 제30권1호
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• pp.112-117
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• 1996

Objective: Standard stress/rest Tc-99m MIBI and T1-201 myocardial perfusion study have some limitations such as stress/rest image overlap for Tc-99m-MIBI, low energy for T1-201 and long period of study time for two separate studies. Separate acquisition rest T1-201/stress Tc-99m MIBI dual isotope study is a potentially efficient myocardial perfusion imaging protocol that combines the high resolution of Tc-99m for stress perfusion assessment and T1-201 for viability assessment. This study assessed the usefulness and diagnostic accuracy for this new approach. Methods: We tried to evaluate sensitivity and specificity of dual isotope separate acquisition protocol in 67 patients. Immediately after resting T1-201 SPECT data was acquired, dipyridamole stress Tc-99m MIBI myocardial perfusion study was performed. Visual analysis was carried out qualitatively with 0 to 3 scoring system for 17 segments of left ventricle in the reconstructed horizontal long axis and short axis slices. Results: Total study was completed within 3 hours. In angiographic correlation, dual isotope SPECT demonstrated high sensitivity(85%) and in a small group of patients, high specificity was also observed (100%). Conclusion: Combined thallium-201/stress Tc-99m MIBI SPECT displayed similiar diagnostic accuracy to protocol using stress/rest Tc-99m MIBI SPECT. This protocol was completed in shorter period than the previous protocols and therefore enhance laboratory throughput and patients convenience.

• The Korean Journal of Nuclear Medicine
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• 제28권3호
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• pp.317-325
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• 1994

The accuracy of dipyridamole stress/rest $^{99m}Tc$-MIBI myocardial imaging for detection of ischemia depends on reproducible image interpretation. To evaluate the reproducibility of visual assessment, agreement in interpretation among two independent observers, blind-ed to clinical data, was evaluated in SPECT images of 131 patients (94 males, 38 females; mean age $58{\pm}7yr$) with suspected coronary artery disease who underwent both dipyridamole stress/rest $^{99m}Tc$-MIBI myocardial SPECT and coronary angiography. The left ventricle was divided into twenty-nine segments in stress and rest SPECT images and each segment was visually graded according to a five-point scale (segmental score : 0=normal, 1=equivocal, 2=mild decrease, 3=severe decrease and 4=absent uptake). Overall concordance of segmental scoring between the two observers was 80%. The Pear-son's correlation coefficient (r) of the segmental scores for stress and rest images were 0.67 and 0.65, respectively, while the difference in score between the two images showed a correlation of 0.45 (all p<0.001). Agreement between two observers in final SPECT diagnosis as absence or presence of disease was 93%. The degree of agreement in segmental scoring showed no difference between patients with or without agreement as to the presence of disease. Therefore it appeared that cases with inconcordant diagnosis between the 2 observers were mainly due to a difference in individual threshold for interpretating the significance of a particular decreased uptake area rather than to a difference in perceiving the degree of the hypoactivity Thus, establishment of individual optimum thresholds in visual interpretation of myocardial SPECT may be helpful to improve reproducibility and accuracy of scan diagnosis.

• The Korean Journal of Nuclear Medicine
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• 제37권3호
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• pp.178-189
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• 2003

Purpose: Cellular uptakes of $^{99m}Tc-sestamibi(MIBI)\;and\;\;^{99m}Tc-tetrofosmin$ into cancer cell lines expressing multidrug resistance(MDR) were investigated and compared. The effects of verapamil and cyclosporin A, well-known multidrug resistant reversing agents, on cellular uptakes of both tracers were also compared. Materials and Methods: Doxorubicin-resistant HCT15/CL02 human colorectal cell and doxorubicin-resistant K562(Adr) and vincristine-resistant K562(Vcr) human leukemic cells were studied. RT-PCR analysis was used for the detection of mdr1 mRNA expression. MDR-reversal effects with verapamil and cyclosporine A were evaluated at different drug concentrations after incubation with MIBI and tetrofosmin for 1, 15, 30, 45 and 60 min, using single-cell suspensions at $1{\times}10^6cells/ml$ incubated at $37^{\circ}C$. Radioactivity in supernatants and pellets were measured with gamma well counter. Results: The cellular uptakes of MIBI and tetrofosmin in K562(Adr) and K562(Vcr) were lower than those of parental K562 cell. In HCT15/CL02 cells and K562(Adr) cells, there were no significant difference in cellular uptakes of both tracers, but cellular uptake of MIBI was higher than that of tetrofosmin in K562(Vcr) cells. Coincubation with verapamil resulted in a increase In cellular uptakes of MIBI and tetrofosmin. Verapamil increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 11.9- and 6.8-fold, by K562(Adr) cell by 14.3- and 8-fold and by K562(Vcr) cell by 7- and 5.7-fold in maximum, respectively. Cyciosporin A increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 10- and 2.4-fold, by K562(Adr) cell by 44- and 13-fold and by K562(Vcr) cell by 18.8- and 11.8-fold in maximum, respectively Conclusion: Taking together, MIBI and tetrofosmin are considered as suitable radiopharmaceuticals for defecting multidrug resistance. However, MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators. Since cellular uptakes of both tracers might differ in different cell types, further experiments regarding differences in cellular uptakes between cell types should be explored.

• The Korean Journal of Nuclear Medicine
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• 제30권4호
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• pp.493-501
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• 1996

To assess contribution of T1-201 rest-24 hour delay redistribution in detection of viable myocardium, we studied the predictive value of this redistribution in 17 patients who peformed rest-24 hour delay perfusion SPECT before bypass surgery. Regional wall motion was compared with gated SPECT in 10 patients and echocardiography in 7 patients before and after bypass surgery. Rest and 24 hour delayed uptakes were scored from 0 (normal perfusion) to 3 (defect). In rest SPECT, 56 segments showed perfusion decrease. Thirty four segments(61%) improved after surgery and were defined as viable Nineteen(34%) segments had more uptake of T1-201 at 24 hour delay, and the other 37 segments did not. In 81%(25/31) of segments with mildly decreased perfusion, wall motion after bypass surgery improved, 57% (8/14) of segments with severely decreased perfusion improved, and 9%(1/11) of segments with defects improved. In 14 among 19 segments which had more T1-201 uptakes at 24 hour delay, wall motion was improved(positive predictive value of redistribution: 74%). 20 among 37 segments which had persistent decreases in rest-24 hour redistribution improved and 17 did not(negative predictive value: 46%). Segments having severe perfusion decrease or defects showed improved wall motion after surgery in 64%(7/11), if it had redistribution at delay. Segments with either mildly decreased uptake in resting or rest-delayed redistribution showed improved wall motion in 76%(32/42). Among the 14 segments which showed improvement in wall motion, 10 had partial reversibility in stress-rest images and the other 4 had persistent perfusion defects in stress-rest images. These 4 segments were found viable only with rest-24 hour delayed perfusion SPECT. We concluded that rest T1-201 uptake or redistribution at 24 hour delay should be referred as an evidence to warrant postoperative improvement of abnormal wall motion and we could predict myocardial viability with preoperative rest-24 hour delay perfusion SPECT in the segments with rest perfusion decreases.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제54권1호
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• pp.45-54
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• 2009

This experiment was conducted to clarify the effects of source and sink related characteristics on grain weight increase and grain nitrogen accumulation in rice. Source was modified by leaf removing treatment with no sink modification in 2002 and sink and source were modified at the same time by different sowing dates, N fertilization rates, row spacings, and thinning treatments at heading in 2007. Grain weight (GW) and grain assimilates produced by photosynthesis during grain-filling ($GW_P$) increased with the increase of source, while the grain assimilates retranslocated from leaf and stem ($GW_T$) decreased. Among the source-related characters, shoot dry weight were most closely related with GW. GW was dependant on $GW_P$ rather than on $GW_T$. Grain nitrogen content (GN) and grain nitrogen absorbed from soil during grain-filling ($GN_S$) increased with the increase of source, while the grain nitrogen retranslocated from leaf and stem ($GN_T$) decreased. Shoot nitrogen content among the source-related characters was related most closely with GN. The contribution of $GN_T$ to GN was relatively large although GN depended more largely on $GN_S$ than $GN_T$. In addition, GN was supplied firstly from $GN_S$ or from $GN_S$ and $GN_T$ at the same time.

• Journal of fish pathology
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• 제18권1호
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• pp.67-80
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• 2005

Phosphoinositide-specific phospholipase $C\delta$ $PLC\delta$) plays an important role in many cellular responses and is involved in the production of second messenger. The present study was conducted to obtain the biochemical characteristics of the expressed recombinant $PLC\delta$ in E. coli cloned from Misgurnus mizolepis and partially purified $PLC\delta$ enzymes from liver tissues of M. mizolepis (wild ML-$PLC\delta$). The ML $PLC\delta$ gene was cloned and expressed under the previous report (Kim et al., 2004), and purified the recombinant protein by successive chromatography using $Ni^{2+}$-NTA affinity column and gel iltration FPLC column. The wild ML-$PLC\delta$ protein was solublized with 2 M KCI and purified by successive chromatography on open heparin-Sephagel and analytical TSKgel heparin-5PW. Both the recombinant and wild ML-$PLC\delta$ form of protein showed a concentration-dependent PLC activity to phosphatidylinositol 4,5-bis-phosphate (PIP$_2$) or phosphatidylinositol (PI). Its activity was absolutely $Ca^{2+}$- dependant, which was similar to mammalian $PLC\delta$ isozymes. Maximal PI-hydrolytic activations of recombinant and wild ML- TEX>$PLC\delta$ was at pH 7.0 and pH 7.5, respectively. In addition, the enzymatic activities of recombinant and wild ML-$PLC\delta$ were increased in concentration-dependent manner by detergent, such as sodium deoxycholate SDC), phosphatidylethanolamine (PE) and phosphatidylcholine (PC). The activities decreased in contrast by a polyamine, such as spermine. Western blotting showed that several types of $PLC\delta$ isozymes exist in various organs. Taken together our results, it suggested that the biochemical characteristics of ML-$PLC\delta$ are similar with those of mammalian $PLC\delta1$ and ${\delta}3$ isozymes.

• Journal of The Korean Society of Grassland and Forage Science
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• 제22권2호
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• pp.123-130
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• 2002

A field experiment was carried out to determine the effect of application level of animal manure on the nitrate nitrogen concentration, sugar content and animal intake of forage sorghum $\times$ sudangrass hybrid (Sorghum bicolor (L.) Moench, cv. Pionee. 988) in 1995. The application amount of animal manure were 50, 100 and 150MT in cattle manure, 20, 40 and 80MT in swine manure, and 10, 20 and 40MT/ha in poultry manure. Non-application plot(control) was involved. The nitrate nitrogen concentration was increased with increasing of application level of animal manure(P<0.05). Average nitrate nitrogen concentration was 397, 512, and 609mg/kg at low, medium and high application level of animal manure. The nitrate nitrogen concentration by plant height was 438mg/kg at 50~60m of plant height, 454mg at 100~120cm, and 418mg at 200~220cm. The nitrate nitrogen concentration of stems was 376mg, and significantly higher than that(135mg) of leaves(P<0.05) regardless of animal manure type, and lower parts of stems and leaves were significantly higher than those of upper parts of plants(P<0.05). Average nitrate nitrogen concentration of leaves was 151mg at lower, and 58mg at upper parts of plants, and the concentration of stems was 357mg at lower, 511mg at middle, and 610mg at upper parts of plants. The sugar contents of sorghum $\times$ sudangrass hybrid was decreased with increasing of application level of animal manure(P<0.05). Average sugar content was 4.9, 4.4, and 4.3。 at low, medium and high application level of animal manure. The sugar content by plant height was 3.9。 at 50~60 and 100~120cm of plant height, and 6.1。 at 200~220cm of plant height. Animal intake of sorghum $\times$ sudangrass hybrid was decreased greatly with increasing of application level of animal manure. Average intake was 73.9, 55.7, and 52.3% at low, medium and high application level of animal manure. The intake by animal manure type was 73.7% in cattle, 59.7% in swine and 62.5% in poultry manure.

• Journal of The Korean Society of Grassland and Forage Science
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• 제22권2호
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• pp.131-136
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• 2002

A field experiment was carried out to compare the nitrate nitrogen concentration, sugar content and animal intake of low $sorghum{\times}sudangrass$ hybrids (Sorghum bicolor (L.) Moench) grown under application of animal manure in 1995. The application amount of animal manure were 40MT in cattle manure, and 30MT/ha in swine and poultry manure. The four NLCF's recommended hybrids used in this study were Pioneer 988, TE-Haygrazer and NC+ 855 (heading type), and Jumbo(headless type). The nitrate nitrogen concentration of forage was 365mg/kg at 50~60cm of plant height, 501mg at 100~120cm, and 502mg at 200~220cm, regardless of animal manure type and cultivar. The nitrate nitrogen concentration of NC+ 855 and P 988 was 519 and 526mg, respectively, and were higher than that(317mg) of Jumbo(P<0.05). The nitrate nioogen concentration of stems was 376mg, and significantly higher than that(135mg) of leaves(P<0.05) regardless of cultivar, and lower parts of stems and leaves were higher than those of upper parts of plants. The sugar contents of four $sorghum{\times}sudangrass$ hybrids were ranged between 3.1 and $3.7^{\circ}$ in cattle manure, 2.9 and $3.3^{\circ}$ in swine manure, and 2.8 and $4.9^{\circ}$ in poultry manure. The sugar content of NC+ 855 was the highest as $3.9^{\circ}$, p 988 was second as $3.4^{\circ}$, and then TE-Haygrazer and Jumbo were lower as $3.2^{\circ}$ and $2.9^{\circ}$, respectively. Animal intake of sorghum ${\times}$ sudangrass hybrids P 988 and NC+ 855 were slightly higher than those of Jumbo and TE-Haygrazer grown under application of cattle manure. Also the average intake of P 988 was a little higher than that of Jumbo. However, there were no significant differences of forage intake among few recommended $sorghum{\times}sudangrass$ hybrids.

• Journal of The Korean Society of Grassland and Forage Science
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• 제29권4호
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• pp.307-312
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity of induced annual legumes at paddy field of Cheonan and Naju from 2004 to 2006. Chinese milk vetch (wild type), crimson clover (C.V. Linkarus), forage pea (C.V. Austrian pea), hairy vetch (C.V. Oregon commen) were used in this study. At the Naju region, the earliest flowering on 2nd may was found in Chinese milk vetch, while the latest on 18th May in forage pea. Fresh, dry matter (DM) and crude protein (CP) yields of crimson clover were highest as 28,870, 6,986 and 943 kg/ha, respectively. but the yield of chinese milk vetch was low by 9,885, 1,749 and 338 kg/ha. At the Cheonan region, the most fast flowering date variety was Chinese milk vetch, hairy vetch was very late as 19th May. Fresh, DM and CP yields of hairy vetch were highest as 7,916, 1,141 and 113 kg/ha, respectively. but the yield of chinese milk vetch showed the lowest by 270, 42 and 8 kg/ha. The CP content of annual legumes was 14.3%. chinese milk vetch showed the highest CP content by 19.3% and hairy vetch showed the lowest content by 9.9%. The present data showed that the productivity was closely dependent on winter hardness, in conclusion, crimson clover at Naju and hairy vetch at Cheonan region was suggested to be the most proper species as winter crop after rice harvest on paddy field when considered the winter hardiness.