• Macromolecular Research
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• v.15 no.3
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• pp.238-243
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• 2007

Nanofibers were prepared by electrospinning a solution of poly(lactic-co-glycolic acid) (PLGA) and their mean diameter was 340 nm. The PLGA nanofibers were treated with a plasma in the presence of either oxygen or ammonia gas to change their surface characteristics. The hydrophilicity of the electrospun PLGA nanofibers was significantly increased by the gas plasma treatment, as confirmed by contact angle measurements. XPS analysis demonstrated that the chemical composition of the PLGA nanofiber surface was influenced by the plasma treatment, resulting in an increase in the number of polar groups, which contributed to the enhanced surface hydrophilicity. The degradation behavior of the PLGA nanofibers was accelerated by the plasma treatment, and the adhesion and proliferation of mouse fibroblasts on the plasma-treated nanofibers were significantly enhanced. This approach to controlling the surface characteristics of nanofibers prepared from biocompatible polymers could be useful in the development of novel polymeric scaffolds for tissue engineering.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.86-93
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• 2004

Nitric oxide (NO) has emerged as an important intracellular and intercellular messenger, controlling many physiological processes and participating in the fertilization process via the autocrine and paracrine mechanisms. This study investigated whether nitric oxide synthase (NOS) inhibitior (L-NAME) and L-arginine could regulate in vitro fertilization and early embryonic development in mice. Mouse epididymal spermatozoa, oocytes, and embryos were incubated in mediums of variable conditions with and without L-NAME or L-arginine (0.5, 1, 5 and 10mM). Fertilization rate and early embryonic development were significantly inhibited by treating sperms or oocytes with L-NAME (93.8% vs 66.3%,92.1% vs 60.3%), but not with L-arginine. In contrast, fertilization rate and early embryonic development were conspicuously reduced when L-NAME or L-arginine was added to the culture media for embryos. Early embryonic development was inhibited by microinjection of L-NAME into the fertilized embryosin a dose-dependent manner, but only by high concentrations of L-arginine. These results suggest that a moderate amount of NO production is essential for fertilization and early embryo development in mice.

• Molecules and Cells
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• v.45 no.11
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• pp.820-832
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• 2022

As a potential candidate to generate an everlasting cell source to treat various diseases, embryonic stem cells are regarded as a promising therapeutic tool in the regenerative medicine field. Cohesin, a multi-functional complex that controls various cellular activities, plays roles not only in organizing chromosome dynamics but also in controlling transcriptional activities related to self-renewal and differentiation of stem cells. Here, we report a novel role of the α-kleisin subunits of cohesin (RAD21 and REC8) in the maintenance of the balance between these two stem-cell processes. By knocking down REC8, RAD21, or the non-kleisin cohesin subunit SMC3 in mouse embryonic stem cells, we show that reduction in cohesin level impairs their self-renewal. Interestingly, the transcriptomic analysis revealed that knocking down each cohesin subunit enables the differentiation of embryonic stem cells into specific lineages. Specifically, embryonic stem cells in which cohesin subunit RAD21 were knocked down differentiated into cells expressing neural alongside germline lineage markers. Thus, we conclude that cohesin appears to control the fate determination of embryonic stem cells.

• Korean Journal of Cognitive Science
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• v.11 no.2
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• pp.37-51
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• 2000

The present study compared computer users target-selection response patterns when the targets were varied in terms of their relative location and distance from the current position of the cursor. In Experiment 1, where the mouse was used as an input device, the effects of different directions and distances of simple target(small rectangle) on target-selection response were investigated. The results of Experiment 1 can be summarized as follows: (1) Overshooting was more frequent than either undershooting or correct movement and (2) this tendency was more prominent when the targets were presented in the oblique direction or in farther location from the current cursor position. (3) Although the overshooting and undershooting were more frequent in the oblique direction, the degree of deviation was larger in horizontal and vertical direction. (4) Time spent in moving the mouse rather than that spent in planning, calibrating or clicking was found to be the most critical factor in determining total response time. In Experiment 2, effects of the font size and line-height of the target on target-selection response were compared with regard to two types of input devices(keyboard vs. mouse). The results are as follows: (1) Mouse generally yielded shorter target-selection time than keyboard. but this tendency was reversed when the targets were presented in horizontal and vertical directions. (2) In general, target-selection time was the longest in the condition of font size of 10 and line-height of 100%, and the shortest in the condition of font size of 12 and line-height of 150%. (3) When keyboard was used as the input device, target-selection time was shortest in the 150% line-height condition, whereas in the mouse condition, target-selection time tended to be increased as the line-height increased. which resulted in the significant interaction effect between input device and line-height. Finally, several issues relating to human-computer interaction were discussed based on the results of the present study.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.308-319
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• 2003

Mechanical forces are known to have an effect on bone formation, maintenance and remodeling, and there is evidence that the development of the mandibular condyle in the rat or mouse is influenced by altered functional force. However, studies are lacking in molecular-biologic mechanism such as the identification of differentiation factor induced from functional force. Here a mouse model was used to investigate the functional stress-responsive gene or factors which is related to the altered force by comparing the expression genes of functional state and hypo-functional state of the mouse mandible. ICR mice were provisioned with either a soft, mushy diet (soft-diet group) or hard rat pellets (hard-diet group) beginning at weaning for the alteration of functional force and subsequently sacrificed at 89 days of age. Incisor of mice in group 1 were trimmed twice a week to reduce occlusal forces. After killing the animals, mandibular bone including condyle were collected for RNA extraction, subtractive hybridization, northern blot analysis and mRNA in-situ hybridization. The results as follows; 1. A total of 39 clones were sequenced, and 11 individual sequence types were subsequently identified by subtractive hybridization, as 28 clones were represented twice in the analyzed sets. 2. Consequently four candidate clones, FS-s (functional stress-specific)2, -5, -18, and -22 were identified and characterized by homolgy search and northern analysis. Four of these clones, FS-s2, -5, -18, and -22, were shown to be expressed differentially in the hard-diet group. 3. Histologic sections showed that osteoblastic activity along the bone trabeculae and active bone remodeling were significantly lower in soft than in hard diet animals. A soft diet seems to enable a longer period of endochondral ossification in the mandibular condyle. 4. Although the mRNAs of FS-s2, -5, -18, and -22 were expressed rarely by cells of the soft-diet group, highest expression was detected in the cells of the hard-diet group. Together with the above results, it is suggested that FS-s2, -5, -18, and -22 could act as an important factors controlling the tissue changes in response to functional stress. The exact functional significance of these findings remains to be established.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.3
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• pp.1-15
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• 2012

Objectives: The purpose of this study was to investigate the effects of Chaenomelis Fructus Herba Water Extract(CF) on the production of inflammatory mediators in RAW 264.7 cell mouse macrophages stimulated with LPS. Methods: We have not examined effect of CF on the cell viability of RAW 264.7 cell until we investigated effects of CF on LPS-induced productions of NO, Ca and various cytokines in RAW 264.7 cell. And when p-value is below 0.05, it is judged to have the significant difference statistically(P<0.05). Results: 1. CF increased the cell viability in the RAW 264.7 cell at the density of 25, 50, 100 and 200 ${\mu}g/ml$. 2. CF inhibited significantly increasing the production of NO in LPS-induced RAW 264.7 cell at the density of 25, 50, 100 and 200 ${\mu}g/ml$. 3. CF inhibited significantly increasing the production of Intracellular Ca in LPS-induced RAW 264.7 cell at the density of 25, 50, 100 and 200 ${\mu}g/ml$. 4. CF inhibited significantly the IL-2, IL-10, IL-12p70, TNF-${\alpha}$, GM-CSF, M-CSF, LIF and VEGF of the RAW 264.7 cell induced by LPS at the density of 25, 50, 100 and 200 ${\mu}g/ml$. 5. CF inhibited significantly the IL-4 at the density of 25, 50 ${\mu}g/ml$, the IL-5, IL-15 and MIG at the density of 25, 50 and 200 ${\mu}g/ml$ and IFN-${\gamma}$ at the density of 25, 100 ${\mu}g/ml$ respectively in the RAW 264.7 cell increased by LPS. Conclusions: CF inhibited significantly increasing IL-2, IL-10, IL-12p70, TNF-${\alpha}$, GM-CSF, M-CSF, LIF, VEGF, NO and Ca in LPS-induced RAW 264.7 cell at the density of more than 25 ${\mu}g/ml$ without causing the toxicity. These results signify that CF has antiinflammatory effect on controlling the over inflammatory reaction by the RAW 264.7 cell.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.1
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• pp.69-77
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• 2000

In retrieving and analyzing digital map information using mouse or key strokes, it needs several times of repeated mouse operation for designating the range of study area. In this study, we proposed a voice activated map information retrieval system for eliminating such repetitions and we realized the system on the personal computer. The system was constructed in two ways - traditional OLE(object linking embedding) method and MFC(Microsoft fundamental class) method in controlling of window display for practical use. In the system performance evaluation, the retrieval data for digital map were consisted of 68 words uttered by 3 male persons which include attribute words and control words for Susung-gu area of Taegu city in a 1:5,000 map. As the results, we obtained the average 98.02% of recognition rate through on-line tests in the office environment and the operating speed of 5.39 seconds by OLE, 10.38 seconds by MFC. These results showed the possibility for practical use of information retrieval system using speech recognition in digital map.

• Journal of Life Science
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• v.18 no.1
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• pp.114-119
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• 2008

The molecular machinery controlling cell cycle is centered around the regulation of the activity of maturation-promoting factor (MPF), a complex composed of a catalytic Cdc2 and the cyclinB regulatory subunit. Cdc2 kinase is inactivated by phosphorylation of inhibitory kinase, Wee1. It has been known that there are three different Wee1 kinases in the mammalian cell, Wee1A, Wee1B and Myt1. To investigate the regulatory mechanism of Wee1 kinases, the phosphorylation and degradation of Wee1A and Wee1B were checked in the Xenopus oocyte cell cycle. When Wee1 kinases were injected into frog oocyte, Wee1B was more stable than Wee1A. Wee1A and Wee1B kinase were phosphorylated by many kinases such as PKA and Akt. The roles of amino or carboxyl terminal in mouse Wee1A or Wee1B kinase were investigated using chimeric constructs. The degree of protein phosphorylation, degradation and cell cycle progression were different between chimeric constructs. The amino domain of Wee1A was implicated in the protein phosphorylation and degradation while amino domain of Wee1B and carboxyl domain of Wee1A were involved in the activity regulation. These results suggested that the domains of Wee1 kinase have different and significant roles in regulating the Wee1 kinases in the cell cycle progression.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.1-12
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• 2002

The periodontal ligament(PDL) is a unique tissue that is crucial for tooth function. However, little is known of the molecular mechanisms controlling PDL function. PDL-specific protein;PDLs22 had been previously identified as a novel protein isolated from cultured human PDL fibroblasts using subtraction hybridization between human gingival fibroblasts and PDL fibroblasts. The aim of this study was to examine the expression pattern and tissue localization of PDLs22 protein in embryonic and various postnatal stages of developing mouse using immunohistochemical staining. Embryos (E18) and postnatal (P1, P4, P5, P15, P18) were decapitated and the heads were fixed overnight in a freshly prepared solution of 4% paraformaldehyde. Some specimens were decalcified for $2{\sim}4$ weeks in a solution containing 10% of the disodium salt of ethylenediamine-tetraacetic acid (EDTA). Next, tissues were dehydrated, embedded in paraffin and sectioned serially at $6{\mu}m$ in thickness. Polyclonal antiserum raised against PDLs22 peptides, ISNKYLVKRQSRD, were made. The localization of PDLs22 in tissues was detected by polyclonal antibody against PDLs22 by means of immunohistochemical staining. The results were as follows; 1. Expression of PDLs22 protein was not detected in the tooth germ of bud and cap stage. 2. At the late bell stage and root formation stage, strong expression of PDLs22 protein was observed in developing tooth follicle, osteoblast-like cells, and subodontoblastic cells in the tooth pulp, but not in gingival fibroblasts, ameloblasts and odontoblasts of tooth germ 3. In erupted tooth, PDLs22 protein was intensely expressed in PDL and osteoblast-like cells of alveolar bone, but not in gingival fibroblasts, mature osteocytes and adjacent salivary glands. 4. In the developing alveolar bone and mid-palatal suture, expression of PDLs22 protein was seen in undifferentiated mesenchymal cells and osteoblast-like cells of developing mid-palatal suture, but not in mature osteocytes and chondrocytes. These results suggest that PDLs22 protein may play an important role in the differentiation of undifferentiated mesenchymal cells in the bone marrow and PDL cells, which can differentiate into multiple cell types including osteoblasts, cementoblasts, and PDL fibroblasts. However, more researches should be performed to gain a better understanding of the exact function of PDLs22 protein which related to the PDL cell differentiation.

• Molecules and Cells
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• v.37 no.10
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• pp.734-741
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• 2014

Histone modifications on major transcription factor target genes are one of the major regulatory mechanisms controlling adipogenesis. Plant homeodomain finger 2 (PHF2) is a Jumonji domain-containing protein and is known to demethylate the histone H3K9, a repressive gene marker. To better understand the function of PHF2 in adipocyte differentiation, we constructed stable PHF2 knock-down cells by using the mouse pre-adipocyte cell line 3T3-L1. When induced with adipogenic media, PHF2 knock-down cells showed reduced lipid accumulation compared to control cells. Differential expression using a cDNA microarray revealed significant reduction of metabolic pathway genes in the PHF2 knock-down cell line after differentiation. The reduced expression of major transcription factors and adipokines was confirmed with reverse transcription- quantitative polymerase chain reaction and Western blotting. We further performed co-immunoprecipitation analysis of PHF2 with four major adipogenic transcription factors, and we found that CCATT/enhancer binding protein (C/EBP)${\alpha}$ and C/EBP${\delta}$ physically interact with PHF2. In addition, PHF2 binding to target gene promoters was confirmed with a chromatin immunoprecipitation experiment. Finally, histone H3K9 methylation markers on the PHF2-binding sequences were increased in PHF2 knock-down cells after differentiation. Together, these results demonstrate that PHF2 histone demethylase controls adipogenic gene expression during differentiation.