• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.83-97
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• 1989

This study was carried out to obtain basic information necessary for aggregation and in-vitro culture of mouse embryos by treating phytohemagglutinin-p (PHA-P). The 4-, 8-cell and morula embryos were obtained from female mice of albino BALE/C, CBA and C57BL strains, those were injected 5 i.u pregenant mare serum gonadotrophin and 5 i.u human chorionic gonadotrophin to superovulation. The zona pellucidia was removed by placing the embryos in Acidic Tyrode solution containing 1.0% protease or/and 5 ug/ml PHA-P. The pairs of zona free embryos were subjected to aggregation by glassneedle in BMOC-3 containing 5 ug/ml PHA-P. The aggregation embryos were cultured in Brinster's mouse ova culture-3(BMOC-3) medium under the gas phase of 5% $CO_2$ in air $37^{\circ}C$ for 13 to 50 hours. The results obtained in this study are summarised as follows : 1. When 4-, 8-cell and morula embryos were zona-freed in acidic Tyrode solution containing 1.0% protease or/and 5 ug/ml PHA-P, and cultured in vitro to blastocysts, the 4- and 8-cell embryos showed slightly less development rates than the morula one did, and solution of 5 ug/ml PHA-P brought some higher development rate than negative control. 2. As 2, 5 or 10 ug/ml PHA-P was added to the solution to aggregate 4-, 8-cell or morula embryos, 2 ug/ml solution represented slightly lower aggregation rate than the higher levels solutions, and 4- and 8-cell embryos showed higher rates than morula one did (P<.05). 3. In respect to the development rates of aggregated embryos to morula no significant difference was found among PHA-P levels and between 4-and 8-cell embryos. With respect to those of aggregated embryos to blastocysts the different levels of PHA-P showed similar results, however, the 4- and 8-cell embryos represented higher rates than the morula one did (P<.05). 4. The mean time necessary for development of aggregated 4-, 8-cell and morula embryos to blastocysts were 38.5-40, 26-27 and 19-20hrs. Respectively in solution for aggregation. 5. The aggregation rates of embryos were 34-94%, when treated protease or/and PHA-P. Supplementation of 5 ug/ml PHA-P to the solution for aggregation showed a trend demonstrating higher aggregation rate compared to negative control, although no significance was found. However, 4- and 8-cell embryos represented significantly higher aggregation rates than the morula one did (P<.05). 6. The development rates of 4- and 8-cell embryos to morula were 52.7-84.7 and 73.8-87.2%, respectively, showing no significant difference between two cell stages. However, the aggregation rates of embryos treated with solution containing PHA-P were higher than negative control (P<.05). 7. The development rates of 4- and 8-cell and morula embryos to blastocysts were 41.7-77.7 78.7-83.0 and 0-19.2%, respectively. The rates of 4-cell embryos treated with PHA-P were significant higher than the negative control (P<.05). The 8-cell and morula embryos also showed more rates when treated PHA-P.

• Development and Reproduction
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• v.17 no.4
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• pp.409-420
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• 2013

Human serum (HS) has been reported to induce aggregation of human eyelid adipose-derived stem cells (HEACs) during high-density culture in vitro. The present study focused on the role of cell adhesion molecules and gelatinases during HS-induced aggregation of HEACs. HS-induced aggregation occurred between 9-15 days of culture. Cells aggregated by HS medium (HS-agg) showed stronger expression of ${\alpha}2$, ${\alpha}2B$, ${\alpha}X$, and CEACAM1 genes compared to non-aggregated cells in HS medium (HS-ex) or in control FBS-cultured cells. HS-agg were distinctly labeled with antibodies against ${\alpha}2$, ${\alpha}2B$, and ${\alpha}X$ proteins. Western blot results demonstrated that the two integrin proteins were greatly expressed in HS-agg compared to HS-ex and control FBS-cultured cells. Treatment of HEACs with anti-integrin ${\alpha}2$ antibody during culture in HS medium delayed aggregation formation. HS-agg exhibited strong expression of MMP1 and MMP9 compared to HS-ex or FBS-cultured cells. Conditioned media from HS-culture showed remarkable increase of MMP9 gelatinolytic activity in comparison to those from FBS-culture. However, there was no change of TIMP mRNA expression in relation to the HS-induced aggregation. Based on these results, it is suggested that integrin ${\alpha}2$, ${\alpha}2B$, and ${\alpha}X$, and MMP9 might play an important role in the HS-induced aggregation of HEACs.

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.887-893
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• 2005

The aggregability of red blood cells (RBCs) was determined by laser backscattering light analysis in a microfluidic channel. Available techniques for RBC aggregation often adopt a rotational Couette-flow using a bob-and-cup system for disaggregating RBCs, which causes the system to be complex and expensive. A disposable microfluidic channel and vibration generating mechanism were used in the proposed new detection system for RBC aggregation. Prior to measurement, RBC aggregates in a blood sample were completely disaggregated by the application of vibration-induced shear. With the present apparatus, the aggregation indexes of RBCs can be measured easily with small quantities of a blood sample. The measurements with the present aggregometer were compared with those of LORCA and the results showed a strong correlation between them. The aggregability of the defibrinogenated blood RBCs is markedly lower than that of the normal RBCs. The noble feature of this design is the vibration-induced disaggregation mechanism, which can incorporate the disposable element that holds the blood sample.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.111-116
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• 1994

This study was carried out to investigate the aggregation rate of isolated mouse 2-, 4- and 8-cell stage blastomeres in phytohemagglutinin(PHA) solution. The morphologically normal embryos were collected from the oviduct of superovulated female mouse by flushing with M2 and the zona pellucida of embryos were removed with 0.5% pronase. The blastomeres were isolated by pipetting after plunging into Ca++-Mg++free PBS for 20 min. The result showed that aggregation rate in 0.5% (84.9~93.1%) was higher than that in 1.0% PHA(76.0~82.1%). Optimal aggregation time was 60min (83.9~100.0%) when compared with 30min (78.8~87.5%). Developmental to blastocyst in recombinated blastomeres was higher under conditions of 0.5% PHA solution and 60-min aggregation than that under other conditions.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.809-814
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• 2003

${\beta}-amyloid$ ($A{\beta}$) peptides from the proteolytic processing of ${\beta}-amyloid$ precursor protein (${\beta}-APP$) aggregates in the brain to form senile plaques, and their aggregation plays a key role in pathogenesis of Alzheimer's disease (AD). To isolate an active compound that has an $A{\beta}$ aggregation-inhibitory activity, 2,000 microbial metabolite libraries were screened based on their ability to inhibit $A{\beta}$ aggregation by using both Congo red and thioflavin T assays. As a result, a water-soluble fraction of a soil microorganism, KK565, showed a potent $A{\beta}$ aggregation-inhibitory activity. The strain was identified as Streptomyces species, based on the cultural and morphological characteristics, the presence of diaminopimelic acid in the cell wall, and the sugar patterns for the whole-cell extract. In addition, the purification of active principle resulted in identifying a heat-unstable protein responsible for the $A{\beta}$ aggregation-inhibitory activity.

• Korea-Australia Rheology Journal
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• v.21 no.3
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• pp.161-173
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• 2009

This study analyzes especially drag and lift models recently developed for fluid-solid, fluid-fluid or liquid-liquid two-phase flows to understand their applicability on the computational fluid dynamics, CFD modeling of pulsatile blood flow. Virtual mass effect and the effect of red blood cells, RBCs aggregation on CFD modeling of blood flow are also shortly reviewed to recognize future tendencies in this field. Recent studies on two-phase flows are found as very useful to develop more powerful drag-lift models that reflect the effects of blood cell's shape, deformation, concentration, and aggregation.

• Journal of Ginseng Research
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• v.41 no.1
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• pp.96-102
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• 2017

Background: Korean ginseng, Panax ginseng Meyer, has been used as a traditional oriental medicine to treat illness and promote health for several thousand years. Ginsenosides are the main constituents for the pharmacological effects of P. ginseng. Since several ginsenosides, including ginsenoside (G)-Rg3 and G-Rp1, have reported antiplatelet activity, here we investigate the ability of G-Rp4 to modulate adenosine diphosphate (ADP)-induced platelet aggregation. The ginsenoside Rp4, a similar chemical structure of G-Rp1, was prepared from G-Rg1 by chemical modification. Methods: To examine the effects of G-Rp4 on platelet activation, we performed several experiments, including antiplatelet ability, the modulation of intracellular calcium concentration, and P-selectin expression. In addition, we examined the activation of integrin ${\alpha}IIb{\beta}_3$ and the phosphorylation of signaling molecules using fibrinogen binding assay and immunoblotting in rat washed platelets. Results: G-Rp4 inhibited ADP-induced platelet aggregation in a dose-dependent manner. We found that G-Rp4 decreased calcium mobilization and P-selectin expression in ADP-activated platelets. Moreover, fibrinogen binding to integrin ${\alpha}IIb{\beta}_3$ by ADP was attenuated in G-Rp4-treated platelets. G-Rp4 significantly attenuated phosphorylation of extracellular signal-regulated protein kinases 1 and 2, p38, and c-Jun N-terminal kinase, as well as protein kinase B, phosphatidylinositol 3-kinase, and phospholipase C-${\gamma}$ phosphorylations. Conclusion: G-Rp4 significantly inhibited ADP-induced platelet aggregation and this is mediated via modulating the intracellular signaling molecules. These results indicate that G-Rp4 could be a potential candidate as a therapeutic agent against platelet-related cardiovascular diseases.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.227-237
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• 2002

A numerical technique for simulating the aggregation of charged particles was presented with a Brownian dynamic simulation in the free molecular regime. The Langevin equation was used for tracking each particle making up an aggregate. A periodic boundary condition was used for calculation of the aggregation process in each cell with 500 primary particles of 16 nm in diameter. We considered the thermal force and the electrostatic force for the calculation of the particle motion. The electrostatic force on a particle in the simulation cell was considered as a sum of electrostatic forces from other particles in the original cell and its replicate cells. We assumed that the electric charges accumulated on an aggregate were located on its center of mass, and aggregates were only charged with pre-charged primary particles. The morphological shape of aggregates was described in terms of the fractal dimension. In the simulation, the fractal dimension for the uncharged aggregate was D$\_$f/ = 1.761. The fractal dimension changed slightly for the various amounts of bipolar charge. However, in case of unipolar charge, the fractal dimension decreased from 1.641 to 1.537 with the increase of the average number of charges on the particles from 0.2 to 0.3 in initial states. In the bipolar charge state, the average sizes of aggregates were larger than that of the uncharged state in the early and middle stages of aggregation process, but were almost the same as the case of the uncharged state in the final stage. On the other hand, in the unipolar charge state, the average size of aggregates and the dispersion of particle volume decreased with the increasing of the charge quantities.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.451-455
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• 2000

Gene targeting are very useful tools for the research on the gene function in vivo, mass production of foreign materials and biomedical approach of therapeutic process. But this process is very complicated and necessary highly skilled technique, because it is very different from ES cell origin, genetic background of embryo, and experimental conditions. We investigated the productivity ability of chimeric mouse after aggregation with TT2 ES cells. Increse of ES cell density caused gradual decrease in embryo development in vitro and in th $\varepsilon$ production of chimeric mice in vivo. One million ES cell density for the aggregation was very efficient to produce high percentage chimeric mice in their coat color. These results suggested that appropriate cell density plays a key role in the development and production of chimeric mice by a 8-cell aggregation method.

• BMB Reports
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• v.52 no.6
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• pp.349-359
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• 2019

After the first research declaring the generation of human induced pluripotent stem cells (hiPSCs) in 2007, several attempts have been made to model neurodegenerative disease in vitro during the past decade. Parkinson's disease (PD) is the second most common neurodegenerative disorder, which is mainly characterized by motor dysfunction. The formation of unique and filamentous inclusion bodies called Lewy bodies (LBs) is the hallmark of both PD and dementia with LBs. The key pathology in PD is generally considered to be the alpha-synuclein (${\alpha}$-syn) accumulation, although it is still controversial whether this protein aggregation is a cause or consequence of neurodegeneration. In the present work, the recently published researches which recapitulated the ${\alpha}$-syn aggregation phenomena in sporadic and familial PD hiPSC models were reviewed. Furthermore, the advantages and potentials of using patient-derived PD hiPSC with focus on ${\alpha}$-syn aggregation have been discussed.