• Progress in Medical Physics
• /
• v.11 no.1
• /
• pp.73-83
• /
• 2000

In this study, we investigate the effects of poor shimming on quantitative measurement of ratios of metabolite levels by proton magnetic resonance spectroscopy ($^1$H MRS). Coefficient of variation (COV) of metabolite ratios for point resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) spectra was evaluated from a phantom containing in vivo levels of metabolites using a conventional whole body 1.5T MR system and conventional acquisition and analysis protocol. A statistical P-value was also calculated from a linear regression for relationship of metabolite ratios. N-acetylaspartate (NAA)/ creatine (Cr) and NAA/ choline (Cho) had low COV values for the long and short TE spectra (29.1 and 27.5%; 23.8 and 12.6 %), whereas Cho/Cr and Cr/Cho had high COV values (50.0 and 68.6 %; 27.5 and 29.3 %). A linear relationship between NAA/Cr and Cho/Cr, and between NAA/Cho and Cr/Cho revealed the statistical significance in the long and short TE spectra, respectively (P < 0.0001 and P < 0.0001; P = 0.015 and P = 0.005). There was no significant relationship between Cho/NAA and Cr/NAA in the measurement (P = 0.159; P = 0.910). The present study suggested that NAA/Cr and NAA/Cho could be useful for data with poor shimming in $^1$H MR spectroscopy. In conclusion, statistical significance of metabolite ratios indicated that the Cr and Cho levels could be interpreted as a significant alteration factor in the long and short TE spectra, and then should be used with care to provide precise metabolite quantification.

• Korean Journal of Microbiology
• /
• v.16 no.1
• /
• pp.16-20
• /
• 1978

Of the eight single acids, only the tyrosine induced the pigmentation. By dint of tracer works of labelled tyrosine with wild type and two mutants, 82% of carboxyl-tyrosine was incroporated, into the primary cellular metabolite and 19% of this was inverted to the red pigment. And 11% was incorporated into the red pigment directly.

• The Korean Journal of Nuclear Medicine
• /
• v.38 no.4
• /
• pp.325-329
• /
• 2004

Purpose: Usefulness of mouse liver S9 fraction was evaluated for the measurement of the metabolites in the in vitro metabolism study of $^{18}F$-labeled radiotracers. Materials and Methods: Mouse liver S9 fraction was isolated at au early step in the course of microsome preparation. The in vitro metabolism studies were tarried out by incubating a mixture containing the radiotracer, S9 fraction and NADPH at $37^{\ciirc}C$, and an aliquot of the mixture was analyzed at the indicated time points by radio-TLC. Metabolic defluorination was further confirmed by the incubation with calcium phosphate, a bone mimic. Results: The radiotracer $[^{18}F]1$ underwent metabolic defluorination within 15 min, which was consistent with the results of the in vivo method and the in vitro method using microsome. Radiotracer $[^{18}F]2$ was metabolized to three metabolites including $4-[^{18}F]fluorobenzoic$ acid within 60 min. It is likely that the one of these metabolites at the origin of radio-TLC was identical with the one that obtained from the in vivo and in vitro (microsome) method. Compared with the in vitro method using microsome, the method using S9 fraction gave a similar pattern of the metabolites but with a different ratio, which can be explained by the presence of cytosol in the S9 fraction. Conclusion: These results suggest that the findings of the in vitro metabolism studies using S9 fraction can reflect the in vivo metabolism of novel radiotracers in the liver. Moreover, this method can be used as a tool to determine metabolic defluorination along with calcium phosphate absorption method.

• Investigative Magnetic Resonance Imaging
• /
• v.2 no.1
• /
• pp.89-95
• /
• 1998

Purpose : To investigate the phosphorus metabolic abnormalities in skeletal muscle of patients with mitochondrial myopathy using in vivo $^{31}P$ magnetic resonance spectroscopy(MRS). Materials and Methods : Patients with mitochondrial myopathy(N=10) and normal control subjects (N=10) participated. All in vivo $^{31}P$ MRS examinations were performed on 1.5T whole-body MRI/MRS system by using an image selected in vivo spectroscopy (ISIS) pulse sequence that provided a $4{\times}4{\times}4{\;}cm^{3}$ volume of interest (VOI) in the right thigh muscle tissue. Peak areas for each phophorus methabolite were measured using a Marquart algorithm. Results : The specific features in patients with mitochondrial myopathy were a significant increase of Pi/PCr ratio (p=0.003) and a significant decrease of ATP/PCr ratio (p=0.004) as compared with normal controls. In particular, the ${\beta}-ATP/PCr$ ratio between controls and patients with mitochondrial myopathy was predominantly altered. Conclusions : In vivo $^{31}P$ MRS may be a useful modality in the clinical evaluation of patients with mitochondrial myopathy based on ATP/PCr and Pi/PCr ratios in skeletal muscle tissue and provides a valuable information in further understanding disorders of muscle metabolism.

• Progress in Medical Physics
• /
• v.7 no.1
• /
• pp.37-52
• /
• 1996

Image-guided localized, water-suppressed in vivo $^1$H MR spectroscopic studies were performed on the patients with brain tumors, acute cerebral infarction and schizophrenia, and dogs. GE Signa 1.5 T whole-body MRI/MRS system using STEAM pulse sequence was used. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. In vivo $^1$H MR spectra in brain neoplastic tissues revealed the changes of signal intensities of N-acetylaspartate (NAA), choline (Cho) and lactate (Lac) resonances. The present results suggest that the observed metabolite alterations from localized, water-suppressed in vivo $^1$H MR spectroscopy can be useful as an index of brain tumors, cerebral infarction and schizophrenia, and provide good quality metabolic information of cerebral tissue in the field of thanato-chronology.

• Journal of Korean Society of Forest Science
• /
• v.100 no.3
• /
• pp.367-373
• /
• 2011

The demand for Japanese larch (Larix kaempferi) seeds has increased in Korea but their supply has been limited due to sporadic natural seed production. To enhance seed production, stem girdling was applied to 42-yearold Japanese larches, resulting in remarkable enhancement of strobilus production in terms of the rate of strobilusbearing tree and the number of strobilus per tree. Metabolic alterations in the girdled and the control trees were interrogated through GC/MS analysis. In the girdled tree, the contents of 14 individual metabolites including polar and non-polar compounds were significantly increased compared to the control. In the cambium and phloem tissues of girdled trees, the contents of pimaric acid, phosphoric acid, sucrose, and two different unknown compounds were enhanced, while the levels of malic acid, inositol, two different disaccharide, 11-trans-Octadecenoic acid and 4 different unknown compounds were decreased compared to the control. The girdled trees showed to be contained significantly higher amount of total nitrogen in the cambium and phloem tissues than that of control trees. Although the role of individual metabolites on enhanced strobilus production remains unclear, the approach presented in this study might provide useful information in elucidating metabolic network modulation induced by girdling and will be further applied for enhanced strobilus production in Japanese larch trees.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.2
• /
• pp.94-99
• /
• 2000

Purpose : With the use of localized, water-suppressed in vivo $^1H$ magnetic resonance spectroscopy (MRS), we evaluated the proton metabolic alterations in patients with chronic alcoholism and healthy normal controls. Material and Methods : Patients with chronic alcoholism (N = 10) and normal control subjects (N = 10) underwent MRS examinations using a stimulated echo acquisition mode (STEAM) pulse sequence with $2{\times}2{\times}2{\;}\textrm{cm}^3$ volume of interest (VOI) in the left cerebellum and basal ganglia. Proton metabolite ratios relative to creative (Cr) were obtained using a Marquart algorithm. Results : The specific feature in patients with chronic alcoholism was a significant decrease of N-acetylaspartate (NAA)/Cr ratio in the left cerebellum, compared with normal controls. No clear correlation of other metabolite ratios such as choline (Cho)/Cr and inositols (Ins)/Cr was established. Conclusion : Our preliminary study suggests that the reduction of NAA/Cr ratio may indicate neuronal loss in patients with chronic alcoholism. Thus, in vivo 1H MRS may be a useful modality in the clinical evaluation of patients with chronic alcoholism based on the proton metabolite ratios.

• Korean journal of applied entomology
• /
• v.50 no.3
• /
• pp.171-178
• /
• 2011

Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late instar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names "Bt-Plus" can be developed into potent biopesticides to increase the efficacy of Bt.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.5
• /
• pp.64-71
• /
• 2018

The purpose of this study is to investigate the characteristics of the substrate of dairy wastewater through aerobic biodegradation and to use the results as the basic data for the efficient treatment of dairy wastewater. The SCODcr of the part of the matter that consisted of readily biodegradable organics (Ss) was 84.2%, which is higher than those of seafood processing wastewater (75.8~77.9%) and pigpen wastewater (58.2%). The proportion of non-biodegradable organics (SI) ranged from 5.6% to 6.4%, and the proportion of inert organics (SIi) generated by microbial metabolism ranged from 3.6 to 3.7%. The content coefficient (YI) of the non-biodegradable dissolved organic matter was in the range of 0.092 to 0.099, and the generation coefficient (Yp) of the inert substance produced by the microbial metabolism was in the range of 0.039 to 0.040. The analysis results of the organic component coefficient showed that approximately 91.0% of the dissolved organic matter of the dairy wastewater was biodegradable, and approximately 92.5% of the dissolved organic matter was the Ss component. Furthermore, the proportion of biodegradable organic matter in the total organic matter (TCODcr) was 89.3%. The proportions of non-biodegradable organics (SI) and non-biodegradable suspended organics (XI) were 3.0% and 7.7%, respectively, which are lower than those in similar wastewater. This means that the milk processing wastewater has a high aerobic biodegradability.

• Journal of The Korean Association For Science Education
• /
• v.23 no.6
• /
• pp.627-633
• /
• 2003

This study is to investigate the level and connection of learning concepts related to metabolism presented in life science textbooks developed according to the national common basic curriculum. One kind of elementary school, and three kinds of middle school and high school science textbooks were analysed. The gross number of concepts related to metabolism was 42 in elementary, 149 in middle and 126 in high school science textbooks. The number of concepts was much more different by school than by publisher. Ratio of the number of concrete versus formal concepts decreased gradationally by grade, but the number of learning concepts increased radically by grade. Thus, it is implied that science learning concepts are presented considering the number of concepts as well as cognitive level of learner, and unit and content are constructed on the connection among them in developing science curriculum and textbooks.