• BMB Reports
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• 제43권9호
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• pp.584-592
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• 2010

Tetrahydrobiopterin (BH4) is a multifunctional cofactor of aromatic amino acid hydroxylases and nitric oxide synthase (NOS) as well as an intracellular antioxidant in animals. Through regulation of NOS activity BH4 plays a pivotal role not only in a variety of normal cellular functions but also in the pathogenesis of cardiovascular and neurodegenerative diseases, which develop under oxidative stress conditions. It appears that a balanced interplay between BH4 and NOS is crucial for cellular fate. If cellular BH4 homeostasis maintained by BH4 synthesis and regeneration fails to cope with increased oxidative stress, NOS is uncoupled to generate superoxide rather than NO and, in turn, exacerbates impaired BH4 homeostasis, thereby leading to cell death. The fundamental biochemical events involved in the BH4-NOS interplay are essentially the same, as revealed in mammalian endothelial, cardiac, and neuronal cells. This review summarizes information on the cellular BH4 homeostasis in mammals, focusing on its regulation under normal and oxidative stress conditions.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
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• pp.72.2-72.2
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• 2006

• Biomaterials and Biomechanics in Bioengineering
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• 제5권1호
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• pp.51-64
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• 2020

In this study, the mathematical model that describes blood cell development in the bone marrow (i.e., hematopoiesis) has been studied via the Homotopy Perturbation Method (HPM). The results from the present work compared very well with the numerical solutions from published literature. This work has shown that the HPM is viable for solving delay differential equations born from hematopoiesis problem. The influence of the proliferating cells loss rate, time delay rate and the phase re-entry rate on the population densities of both the proliferating and resting cells were also determined through the underlined procedure.

• Journal of Animal Science and Technology
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• 제57권4호
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• pp.16.1-16.7
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• 2015

A well-characterized sperm specific protein of the Member of immunoglobulin superfamily, IZUMO1, has crucial role in fertilization by mediating sperm binding to the egg plasma membrane in the mouse. However little is known about IZUMO1 in bovine. Here, we describe the molecular cloning and expression analysis of bovine IZUMO1 (bIZUMO1). RT-PCR and Western blot analysis of the bovine tissues indicated that bIZUMO1 was specifically expressed in the testis and sperm, Furthermore, the result of our biotinylation assay from ejaculated bovine sperm strongly suggest the assumption that bIZUMO1 is localized on the cell surface. These data imply the potential role of bovine IZUMO1 in mammalian fertilization.

• Animal cells and systems
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• 제4권3호
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• pp.195-200
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• 2000

In this article I discuss the main results of our research in space biology from the simple early investigations with human Iymphocytes in the early eighties until the projects in tissue engineering of the next decade on the international space station ISS. The discovery that T Iymphocyte activation is nearly totally depressed in vitro in 0g conditions showed that mammalian single cells are sensitive to the gravitational environment. Such finding had important implications in basic research, medicine and biotechnology. Low gravity can be used as a tool to investigate complicated and still obscure biological process from a new perspective not available to earth-bound laboratories. Low gravity may also favor certain bioprocesses involving the growth of tissues and thus lead to commercial and medical applications. However, shortage of crew time and of other resources, lack of sophisticated instrumentation, safety constraints pose serious limits to biological endeavors in space laboratories.

• The Korean Journal of Physiology and Pharmacology
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• 제5권6호
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• pp.479-485
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• 2001

The existence of opioid receptors in mammalian cerebellum except human, has not been clearly understood. In the present study, we found that NPY was inducible by morphine in the mouse cerebellar granular and Purkinje cell layers. We performed in situ RT-PCR and immunohistochemistry to characterize the NPY expression. The increase of NPY gene expression by morphine (30 mg/kg, i.p.) was inhibited by pretreatment with not only naloxone (100 mg/kg, i.p.) but also a noncompetitive NMDA antagonist, MK-801 (0.3 mg/kg, i.p.). The competitive NMDA antagonist, AP-5 (0.9 mg/kg, i.p.) slightly attenuated the increased NPY expression by morphine. Also, the finding similar to morphine was shown by NMDA (70 mg/kg, i.p.) treatment. Our results indicate that NPY was inducible by morphine and this might reflect activation of NMDA receptors in granule cells that relay mossy fiber inputs to Purkinje cells via parallel fibers.

• KSBB Journal
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• 제8권1호
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• pp.28-35
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• 1993

The serum free medium was developed and used for the suspension culture of mammalian cells. Although there were the problems of the longer lag time and the smaller maximum cell concentration achievable, the higher specific productivity as well as other advantages of the serum free medium can make it a more realistic alternative. The existence of a staggering period in glucose concentration vs. time profile in the batch culture can be a practical indicating signal for performing fed batch culture. The concentration dependence of the effects of the additives in the serum free medium as well as its economic feasibility was also tested.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2003년도 한국생물과학협회 학술발표대회
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• pp.161.2-161
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• 2003

No Abstract, See Full Text

• 약학회지
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• 제43권5호
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• pp.614-622
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• 1999

The standard operation procedure of mouse lymphoma L5178Y $tk^{+/-}-3.7.2C$ gene mutation assay (MOLY) has been regarded as a sensitive in vitro mammalian cell gene mutation assay that is capable of detecting clastogens as well as mutagens. Using MOLY, one of natural sweetner, stevioside (5mg/ml) and its aglycon, steviol ($340{\;}\mu\textrm{g}/ml$) were evaluated the mutagenicity. Stevioside and steviol did not induce mutagenicity in MOLY. On the other hand, stevioside (250mg/kg, B.W.) and steviol (200mg/kg, B.W.) were also evaluated their ability to induce micronuclei in regenerating hepatocytes and bone marrow cells of ddY mice. From these results, stevioside and steviol did not induce any mutagenic effect both MOLY and in vivo micronucleus test.

• Molecules and Cells
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• 제41권5호
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• pp.373-380
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• 2018

Synapses and neural circuits form with exquisite specificity during brain development to allow the precise and appropriate flow of neural information. Although this property of synapses and neural circuits has been extensively investigated for more than a century, molecular mechanisms underlying this property are only recently being unveiled. Recent studies highlight several classes of cell-surface proteins as organizing hubs in building structural and functional architectures of specific synapses and neural circuits. In the present minireview, we discuss recent findings on various synapse organizers that confer the distinct properties of specific synapse types and neural circuit architectures in mammalian brains, with a particular focus on the hippocampus and cerebellum.