• 전자공학회논문지D
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• 제35D권5호
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• pp.80-86
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• 1998

Material characterizations were performed for In$_{0.53}Ga_{0.47}As/In$_{0.52}Al_{0.48}$/As MQWs grown on InP substrates by low-temperature modlecular beam epitaxy. MQW samples were grwon at different temperatures of 200.deg.C, 300.deg. C and 500.deg. C, and doped with 10$^{18}$ cm$^{3}$ Be. High resolution x-ray diffraction measurement showed the change in crystal qualities according to growth temperature. Hall measurement showed the changes in carrier concentrations and mobilities for different growth temperatures. The optical properties of MQW samples were investigated with photoluminescence and fourier-transform infrared spectroscopy measurements.

• Toxicological Research
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• 제18권3호
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• pp.259-265
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• 2002

Resveratrol, a phytoalexin found in grapes, berries, and peanuts, is one of the most promising agents for cancer prevention. Recent studies show that the antitumor activity of resveratrol occurs through p53-mediated apoptosis. This study demonstrated the mechanism that resveratrol induced apoptosis in human osteosarcoma Saos-2 cells lacking p53. Treatment of osteosarcoma Saos-2 cells with resveratrol resulted in decrease of cell viability, which was revealed as apoptosis characterized by activation of caspase-3 protease as well as cleavage of poly(ADP-ribose) polymerase (PARP) with change of mitochondrial membrane potential transition. These results suggest that resveratrol may be potentially useful to treat osteosarcoma via activation of caspase protease and mitochondrial dysfunction.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1617-1620
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• 2012

Background: Gold nanoparticles have recently been investigated with respect to biocompatibility according to their interactions with cells. The purpose of this study was to examine cytotoxicity and apoptosis induction by well-characterized gold nanoparticles in human breast epithelial MCF-7 cells. Methods: Apoptosis was assessed by TUNEL, cytotoxicity by MTT assay and caspase 3, 9, p53, Bax and Bcl expression by real-time PCR assays. Results: Gold nanoparticles at up to $200\;{\mu}g/mL$ for 24 hours exerted concentration-dependent cytotoxicity and significant upregulation of mRNA expression of p53, bax, caspase-3 & caspase-9, whereas expression of antiapoptotic bcl-2 was down-regulated. Conclusion: To the best of our knowledge this is the first report showing that gold nanoparticles induce apoptosis in MCF-7cells via p53, bax/bcl-2 and caspase pathways.

• 대한의생명과학회지
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• 제18권4호
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• pp.420-427
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• 2012

Sprague-Dawley (SD) rats were orally administered with NG-nitro-L-arginine methyl ester (L-NAME), which inhibits or blocks the production of nitric oxide from L-arginine in vascular endothelial cells and vessel tissue. We examined the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and confirms the apoptosis induced by the suppressed nitric oxide activity in the kidney. This study was performed to investigate correlation between the activities of nitric oxide and apoptosis by immunohistochemical changes of apoptotic control proteins with regulated chronic inhibition of nitric oxide. In the kidney from L-NAME-treated group, immunohistochemical reaction to the antigens of apoptosis inhibiting proteins such as bcl-2 and bcl-xL, exhibited a time-dependent reduction. The expression of apoptosis-inhibiting proteins such as bax and p53 increased expression in proportion to the duration of treatment. The most sensitive apoptosis regulating proteins to L-NAME were p53 in stimulation and bcl-2 in inhibition, respectively.

• Molecular & Cellular Toxicology
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• 제4권4호
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• pp.311-317
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• 2008

Zebrafish were exposed to commercial silver nanoparticles (${\sim}$10-20 nm) at 0.4 and 4 ppm during cadual fin regeneration. The silver was in the $Ag^+$ ionic form. Fin regeneration was slow in the group exposed to the lower concentration. The cadual fin, gill, and muscle were assayed after 48 hours and subjected to histological analysis. In all tissues sampled, fish exposed to nanoparticles exhibited infiltration, large mitochondria with empty matrices, and accumulation of nano-sized silver in blood vessels. The results suggested mitochondrial damage and induction of inflammation. Microarray analysis of RNA from young zebrafish (52 hours post-fertilization) that were exposed to nanometer-sized silver particles, showed alteration in expression of the p53 gene pathway related to apoptosis. Gene expression changes in the nanoparticle-treated zebrafish led to phenotypic changes, reflecting increased apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8397-8403
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• 2016

Background: Breast cancer (BCa) is the most common malignancy in Mexican women. A set of histopathological markers has been established to guide BCa diagnosis, prognosis and treatment. Nevertheless, in only a few Mexican health services, such as that of the Secretariat of National Defense (SEDENA for its acronym in Spanish), are these markers commonly employed for assessing BCa. The aim of this study was to explore the association of Ki67, TP53, HER2/neu, estrogenic receptors (ERs) and progesterone receptors (PRs) with BCa risk factors. Materials and Methods: Clinical histories provided background patient information. Immunohistochemical (IHC) analysis was conducted on 48 tissue samples from women diagnosed with BCa and treated with radical mastectomy. The Chi square test or Fisher exact test together with the Pearson and Spearman correlation were applied. Results: On average, patients were $58{\pm}10.4$ years old. It was most common to find invasive ductal carcinoma (95.8%), histological grade 3 (45.8%), with a poor Nottingham Prognostic Index (NPI; 80.4%). ERs and PRs were associated with smoking and alcohol consumption, metastasis at diagnosis and Ki67 expression (p<0.05). PR+ was also related to urea and ER+ (p<0.05). Ki67 was associated with TP53 and elevated triglycerides (p<0.05), and HER2/neu with ER+, the number of pregnancies and tumor size (p<0.05). TP53 was also associated with a poor NPI (p<0.05) and CD34 with smoking (p<0.05). The triple negative status (ER-/PR-/HER2/neu-) was related to smoking, alcohol consumption, exposure to biomass, number of pregnancies, metastasis and a poor NPI (p<0.05). Moreover, the luminal B subty was associated with histological type (p=0.007), tumor size (p=0.03) and high cholesterol (p=0.02). Conclusions: Ki67, TP53, HER2/neu, ER and PR proved to be related to several clinical and pathological factors. Hence, it is crucial to determine this IHC profile in women at risk for BCa. Certain associations require further study to understand physiological/biochemical/molecular processes.

• Molecules and Cells
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• 제43권10호
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• pp.889-897
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• 2020

K-RAS is frequently mutated in human lung adenocarcinomas (ADCs), and the p53 pathway plays a central role in cellular defense against oncogenic K-RAS mutation. However, in mouse lung cancer models, oncogenic K-Ras mutation alone can induce ADCs without p53 mutation, and loss of p53 does not have a significant impact on early K-Ras-induced lung tumorigenesis. These results raise the question of how K-Ras-activated cells evade oncogene surveillance mechanisms and develop into lung ADCs. RUNX3 plays a key role at the restriction (R)-point, which governs multiple tumor suppressor pathways including the p14^ARF-p53 pathway. In this study, we found that K-Ras activation in a very limited number of cells, alone or in combination with p53 inactivation, failed to induce any pathologic lesions for up to 1 year. By contrast, when Runx3 was inactivated and K-Ras was activated by the same targeting method, lung ADCs and other tumors were rapidly induced. In a urethane-induced mouse lung tumor model that recapitulates the features of K-RAS-driven human lung tumors, Runx3 was inactivated in both adenomas (ADs) and ADCs, whereas K-Ras was activated only in ADCs. Together, these results demonstrate that the R-point-associated oncogene surveillance mechanism is abrogated by Runx3 inactivation in AD cells and these cells cannot defend against K-Ras activation, resulting in the transition from AD to ADC. Therefore, K-Ras-activated lung epithelial cells do not evade oncogene surveillance mechanisms; instead, they are selected if they occur in AD cells in which Runx3 has been inactivated.

• 한국식품영양과학회지
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• 제20권6호
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• pp.621-628
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• 1991

Heat-stable enterotoxin(ST) from enterotoxigenic E. coli eKT-53($ST^{+}\;LT^{-}$, transformant from isolate KM-7) that was produced in succinate salts medium. The culture supernatant(crude ST) was purifed by mulitpled steps and investigated some characterization of the ST. The heatstability of purified ST activity was completely lost by treating at $100^{\circ}C$ for 30minutes. ST activity was lost by treatment at pH 1 and 12 conditions, while the activity was not reduced by treatment at pH 2~10, and then the ${\alpha}-amylase$ and pepsin was not decreased activity but disulfide reducing agnets was lost the activity. The molecular weight of the purified ST was approximately 4,200, the isoelectric point was about 4.0.

• 대한수학회보
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• 제53권1호
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• pp.303-323
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• 2016

For a canonical threefold X, it is known that $p_n$ does not vanish for a sufficiently large n, where $p_n=h^0(X,\mathcal{O}_X(nK_X))$. We have shown that $p_n$ does not vanish for at least one n in {6, 8, 10}. Assuming an additional condition $p_2{\geq}1$ or $p_3{\geq}1$, we have shown that $p_{12}{\geq}2$ and $p_n{\geq}2$ for $n{\geq}14$ with one possible exceptional case. We have also found some inequalities between ${\chi}(\mathcal{O}_X)$ and $K^3_X$.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2000년도 제30회 학술심포지엄
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• pp.39-43
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• 2000

HBV는 인체에 감염하여 간염, 간경변 및 간암을 유발하는 hepadnaviruses의 일종으로써 임상적으로 매우 중요한 바이러스이다. 그러나 이 바이러스에 의한 간암(HCC)의 발생 메커니즘은 아직 불확실하다. 최근에는 HBV의 X 단백질(HBx)이 간암 발생에 중요한 역할을 수행하는 것으로 보고되고 있다. HBx 단백질은 전사 활성인자(transcriptional activator)로써 숙주세포의 유전자발현에 영향을 미치어 세포증식 및 분화에 영향을 줄 수 있다. 본 연구에서는 HBx 단백질이 NIH 3T3 cell의 증식 및 형질전환에 미치는 영향을 조사하였다. HBx 단백질을 발현하는 세포주는 정상세포에 비하여 증식 속도가 2배 정도 빠르며, soft agar assay 결과에 의하면 대조군과 비교하여 더 많은 수의 colony를 형성하였다. 또한, 이들 HBx 발현 세포들은 접촉 저해 능력을 상실하여 HBx가 세포 형질 전환 능력을 가짐을 알수 있다 또한 HBx 발현 세포주에 있어서 p21의 RNA 및 protein수준이 정상세포에 비하여 낮으므로 HBx에 의한 증식 촉진 및 세포 형질 전환이 p21을 매개하여 이루어 짐을 알 수 있었다. HBx에 의한 p21 유전자의 발현 감소는 p21의 전사 수준에서 이루어지며 이는 p53-비의존적 경로에 의하여 이루어졌다.