• Molecules and Cells
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• v.21 no.2
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• pp.174-185
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• 2006

Toll-like receptors (TLRs) were evolved to detect invading pathogens and to induce innate immune responses in order to mount host defense mechanisms. It becomes apparent that the activation of certain TLRs is also modulated by endogenous molecules including lipid components, fatty acids. Results from epidemiological and animal studies demonstrated that saturated and polyunsaturated dietary fatty acids can differentially modify the risk of development of many chronic diseases. Inflammation is now recognized as an important underlying etiologic condition for the pathogenesis of many chronic diseases. Therefore, if the activation of TLRs and consequent inflammatory and immune responses are differentially modulated by types of lipids in vivo, this would suggest that the risk of the development of chronic inflammatory diseases and the host defense against microbial infection may be modified by the types of dietary fat consumed.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.268-272
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• 2012

Nephrotoxicity occurs when kidney-specific detoxification and excretion do not work properly due to the damage or destruction of kidney function by exogenous or endogenous toxicants. Exposure to drugs often results in toxicity in kidney which represents the major control system maintaining homeostasis of body and thus is especially susceptible to xenobiotics. Understanding the toxic mechanisms for nephrotoxicity provides useful information on the development of drugs with therapeutic benefits with reduced side effects. Mechanisms for drug-induced nephrotoxicity include changes in glomerular hemodynamics, tubular cell toxicity, inflammation, crystal nephropathy, rhabdomyolysis, and thrombotic microangiopathy. Biomarkers have been identified for the assessment of nephrotoxicity. The discovery and development of novel biomarkers that can diagnose kidney damage earlier and more accurately are needed for effective prevention of drug-induced nephrotoxicity. Although some of them fail to confer specificity and sensitivity, several promising candidates of biomarkers were recently proved for assessment of nephrotoxicity. In this review, we summarize mechanisms of drug-induced nephrotoxicity and present the list of drugs that cause nephrotoxicity and biomarkers that can be used for early assessment of nephrotoxicity.

• KDI Journal of Economic Policy
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• v.41 no.3
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• pp.1-38
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• 2019

Given capital market imperfections, an entrepreneur can alleviate financial frictions by creating a pyramidal business group in which a parent firm offers its subsidiary firm internal finance. This endogenous creation of pyramidal business groups can beget asymmetric financial frictions between business-group firms and stand-alone firms. I build a model to show that these asymmetric financial frictions can have sizable effects on resource allocation. On one hand, the financial advantage of pyramidal business groups can foster productive firms by incorporating them as subsidiaries. On the other hand, the asymmetrically large amount of external capital controlled by pyramidal business groups can be expended by unproductive business-group firms and push up the equilibrium price of capital. The model suggests that with fine investor protection or low financial frictions, the benefits of pyramidal business groups can be dominated by their costs because the probability of fostering productive subsidiaries diminishes as the efficiency of external capital markets improves, while the prevalence of pyramidal business groups is not attenuated due to their continuing asymmetric financial advantage.

• KDI Journal of Economic Policy
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• v.41 no.3
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• pp.77-96
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• 2019

This paper examines the relation between the skill premium and international trade given differences in the relative supply of skills across countries while allowing the South (developing countries) to develop its appropriate technology. Typical assumptions put forward in the literature state that either technology is exogenously given, or technical change is allowed only in the North (developed countries). I present a model of international trade with endogenous growth by allowing the South to direct its technology. The results show that more R&D is directed towards skill-augmenting technology in the North than in the South, in sectors with the same skill-intensity. Technical change induced by lowering trade costs can increase the skill premium in both the North and the South. This result can explain the empirical observation that the skill premium has increased within many developing countries after they experienced trade liberalization. Finally, the model predicts larger gains from trade compared with the model where technical change is either not allowed, or allowed only in the North.

• BMB Reports
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• v.48 no.5
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• pp.249-255
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• 2015

PTPRT/RPTPρ is the most recently isolated member of the type IIB receptor-type protein tyrosine phosphatase family and its expression is restricted to the nervous system. PTPRT plays a critical role in regulation of synaptic formation and neuronal development. When PTPRT was overexpressed in hippocampal neurons, synaptic formation and dendritic arborization were induced. On the other hand, knockdown of PTPRT decreased neuronal transmission and attenuated neuronal development. PTPRT strengthened neuronal synapses by forming homophilic trans dimers with each other and heterophilic cis complexes with neuronal adhesion molecules. Fyn tyrosine kinase regulated PTPRT activity through phosphorylation of tyrosine 912 within the membrane-proximal catalytic domain of PTPRT. Phosphorylation induced homophilic cis dimerization of PTPRT and resulted in the inhibition of phosphatase activity. BCR-Rac1 GAP and Syntaxin-binding protein were found as new endogenous substrates of PTPRT in rat brain. PTPRT induced polymerization of actin cytoskeleton that determined the morphologies of dendrites and spines by inhibiting BCR-Rac1 GAP activity. Additionally, PTPRT appeared to regulate neurotransmitter release through reinforcement of interactions between Syntaxin-binding protein and Syntaxin, a SNARE protein. In conclusion, PTPRT regulates synaptic function and neuronal development through interactions with neuronal adhesion molecules and the dephosphorylation of synaptic molecules. [BMB Reports 2015; 48(5): 249-255]

• Animal cells and systems
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• v.13 no.1
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• pp.49-57
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• 2009

For the study of the reproductive mechanism associated with the process of vitellogenesis, oocyte development and vitellogenesis during oogenesis in female Boleophthalmus pectinirostris were investigated by electron microscopic observations. The ovary consists of a pair of saccular structures with many ovarian lobules. In the early vitellogenic oocyte, the Golgi complex plays an important role leading to the formation of yolk vesicles containing carbohydrate yolks. At this time many pinocytotic vesicles containing yolk precursors are observed in the cytoplasm near the region of initial formation of the zona radiata. In the late vitellogenic oocytes, the multivesicular bodies, which are formed by modified mitochondria, are involved in the formation of the primary yolk granules. Precursors of yolk granules and multivesicular bodies develop to primary yolk globules with participation of pinocytotic vesicles. After primary yolk globules mix with each other, they develop into secondary and tertiary yolk globules. Based on these findings, vitellogenesis of B. pectinirostris occurs by way of the processes of endogenous autosynthesis and exogenous heterosynthesis. The process of autosynthesis involves the combined activity of the Golgi complex, mitochondria, and multivesicular bodies. However, the process of heterosynthesis involves pinocytotic incorporation of extraovarian precursors into the zona radiata of vitellogenic oocytes by way of the thecal cell layers and granulosa cells.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.11
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• pp.191-201
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• 2021

This article examines the role of financial development in economic growth in a number of transitional economies where the financial systems were newly established or reformed only in the early 1990s to facilitate their transition from centrally planned economies to market-based ones. Based on a dataset collected from 29 transitional economies and 5 Asian developing economies covering the period 1990-2020, an empirical endogenous growth model is specified and estimated using the generalized method of moments (GMM). Three measures of financial development are used to investigate the relative role of the banking system and stock exchange market in the process of transition and growth. The results show that the three measures of financial development are crucial determinants of economic growth in transitional economies but the link seems to be in an inverted U-shape. This suggests the existence of thresholds for different channels of the financial sector to expand to positively influence growth. When becoming too large relative to the size of the economy, the financial system would have become a factor not conducive to growth. The growth convergence hypothesis is also confirmed and the impacts of other growth determinants are overall consistent with the extant literature.

• IMMUNE NETWORK
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• v.19 no.1
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• pp.1.1-1.13
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• 2019

Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease characterized by production of autoantibodies to various nuclear antigens and overexpression of genes regulated by IFN-I called IFN signature. Genetic studies on SLE patients and mutational analyses of mouse models demonstrate crucial roles of nucleic acid (NA) sensors in development of SLE. Although NA sensors are involved in induction of antimicrobial immune responses by recognizing microbial NAs, recognition of self NAs by NA sensors induces production of autoantibodies to NAs in B cells and production of IFN-I in plasmacytoid dendritic cells. Among various NA sensors, the endosomal RNA sensor TLR7 plays an essential role in development of SLE at least in mouse models. CD72 is an inhibitory B cell co-receptor containing an immunoreceptor tyrosine-based inhibition motif (ITIM) in the cytoplasmic region and a C-type lectin like-domain (CTLD) in the extracellular region. CD72 is known to regulate development of SLE because CD72 polymorphisms associate with SLE in both human and mice and CD72^-/- mice develop relatively severe lupus-like disease. CD72 specifically recognizes the RNA-containing endogenous TLR7 ligand Sm/RNP by its extracellular CTLD, and inhibits B cell responses to Sm/RNP by ITIM-mediated signal inhibition. These findings indicate that CD72 inhibits development of SLE by suppressing TLR7-dependent B cell response to self NAs. CD72 is thus involved in discrimination of self-NAs from microbial NAs by specifically suppressing autoimmune responses to self-NAs.

• Development and Reproduction
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• v.20 no.3
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• pp.227-235
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• 2016

Ultrastructural studies on oocyte development and vitellogenesis in oocytes, and the functions of follicle cells during oogenesis and oocyte degeneration were investigated to clarifyb the reproductive mechanism on vitellogenesis of Scapharca subcrenata using electron microscope observations. In this study, vitellogenesis during oogenesis in the oocytes occured by way of autosynthesis and heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. However, the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes before the formation of the vitelline coat. In this study, follicle cells, which attached to the previtellogenic and vitellogenic oocytes, were easily found. In particular, the follicle cells were involved in the development of previtellogenic oocytes by the supply of nutrients, and vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors. Based on observations of follicle cells attached to degenerating oocytes after spawning, follicles of this species are involved in lysosomal induction of oocyte degeneration for the resorption phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves. In this study, the functions of follicle cells can accumulate reserves of lipid granules and glycogen particles for vitellogenesis from degenerating oocytes after spawning.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.71-77
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• 2012

Many of biochemical or physiological processes can be regulated by non-coding RNAs as well as coding RNAs in plants, animals and microbes. Recently, many small RNAs including microRNAs (miRNAs) and endogenous small interference RNAs (siRNAs) and long non-coding RNAs have been discovered from ubiquitous organisms including plants. Biotic and abiotic stresses are main causal agents of crop losses all over the world. Much efforts have been performed for understanding the complex mechanism of stress responses. Up to date, many of these researches have been related with the identification and investigation of stress-related proteins, showing limitation to resolve the complex mechanism. Recently, non-coding RNAs as well as coding genes have been gradually interested because of its potential roles in plant stress responses as well as other biophysical aspects. In this review, various potential roles of non-coding RNAs, especially miRNAs and siRNAs, are reviewed in relation with plant biotic and abiotic stresses.