• Radiation Oncology Journal
• /
• 제34권4호
• /
• pp.239-249
• /
• 2016

Tumor hypoxia, a common feature occurring in nearly all human solid tumors is a major contributing factor for failures of anticancer therapies. Because ionizing radiation depends heavily on the presence of molecular oxygen to produce cytotoxic effect, the negative impact of tumor hypoxia had long been recognized. In this review, we will highlight some of the past attempts to overcome tumor hypoxia including hypoxic radiosensitizers and hypoxia-selective cytotoxin. Although they were (still are) a very clever idea, they lacked clinical efficacy largely because of 'reoxygenation' phenomenon occurring in the conventional low dose hyperfractionation radiotherapy prevented proper activation of these compounds. Recent meta-analysis and imaging studies do however indicate that there may be a significant clinical benefit in lowering the locoregional failures by using these compounds. Latest technological advancement in radiotherapy has allowed to deliver high doses of radiation conformally to the tumor volume. Although this technology has brought superb clinical responses for many types of cancer, recent modeling studies have predicted that tumor hypoxia is even more serious because 'reoxygenation' is low thereby leaving a large portion of hypoxic tumor cells behind. Wouldn't it be then reasonable to combine hypoxic radiosensitizers and/or hypoxia-selective cytotoxin with the latest radiotherapy? We will provide some preclinical and clinical evidence to support this idea hoping to revamp an enthusiasm for hypoxic radiosensitizers or hypoxia-selective cytotoxins as an adjunct therapy for radiotherapy.

• 한국자원식물학회지
• /
• 제26권3호
• /
• pp.403-409
• /
• 2013

This study has assessed the anti-oxidative activities and cytotoxic effects of Lithospermum erythrorhizon ethanol extract and measured the effects of tyrosinase inhibition activities with a goal of estimating the usage of the medicinal plant as an ingredient of cosmetics. First, to perform a basic test on the extract, pH and UV-spectrum were measured. According to the measurement, the extract had control functions at pH 5.5, and maximum absorbance occurred at 530nm. In particular, DPPH (1-1-diphenyl-2-picryl-hydrazyl)-inhibiting activity (IC50) and polyphenol content were 149.81 ${\mu}g/mL$ and $51.28{\pm}2.52$ mg/mL respectively. In addition, as extract concentration increased, tyrosinase inhibition activities improved as well. In raw 264.7 cell-based MTT assay, cell survival rates were 98% at 1000 ppm and 153% at 100 ppm. Therefore, it's been confirmed that there is almost no cytotoxin. According to the test results above, it appears that the Lithospermum erythrorhizon ethanol extract would be effective in anti-oxidation and application as a cosmetic ingredient.

• Journal of Microbiology and Biotechnology
• /
• 제13권5호
• /
• pp.666-672
• /
• 2003

Vacuolar degeneration of the gastric epithelial cells is a characteristic feature of the derangement of mucosa where Helicobacter pylori colonizes, and H. pylori vacuolating cytotoxin (VacA) has been suggested to playa key role in it. To elucidate the VacA-involved degenerative mechanism, VacA was purified, and its impact on degeneration of HeLa cells was determined. In the presence of ammonium chloride, cell vacuolation by VacA was dose-and time-dependent, however, no detectable degeneration of the cells was observed with the VacA concentration tested. A further increase of vacuolation was shown in cells pre-treated with diethyl pyrocarbonate (DEPC) , and this resulted in a change of the cell morphology to become spherical. Similar phenomena were also observed when HeLa cells were co-cultivated with intact H. pylori cells. It was remarkable to note that the degree of growth inhibition was proportional to the increase in vacuole formation, suggesting that the vacuolation rate would be critical for cell degeneration. Surprisingly, although VacA was itself inhibited by DEPC, its uptake was markedly increased by this agent, similar to that found in cells with Nabutyrate. These data indicate that the cell's tolerance of VacA transport may be critical for vacuolar degeneration and may be changeable during H. pylori inhabitation.

• Journal of Microbiology
• /
• 제38권1호
• /
• pp.1-7
• /
• 2000

Eight strains of Aeromonas hydrophila isolated from diseased trout in Korea were characterized and compared with an American type strain by various methods including biochemical and physiological tests, PCR, randomly amplified polymorphic DNA (RAPD), plasmid profiling, and gel electrophoresis of total, membrane, and extracellular proteins. Virulence factors such as surface array proteins, cytotoxin, hemolysin, haemagglutinin, and protease were also investigated. The Korean strains showed heterogeneity in Iysine decarboxylase production, utilization of various carbon sources, and production of acetoin. Five strains had the same profiles of total and membrane proteins. Six strains haemagglutinated with trout red blood cells (RBCs) which was inhibited by fucose, galactose, and mannose, except for No. 1 where haemagglutination was inhibited by only galactose and mannose, but not by fucose. Four isolates haemagglutinated with human RBCs which was inhibited by fucose and mannose yet not by galactose. The type strain haemagglutinated only with trout RBCs which was inhibited by fucose, galactose, and mannose. Every isolate secreted protease, hemolysin, cytotoxin, and siderophore, but no enterotoxin. Results showed that the Korean isolates, except for No.7, had very different biochemical and molecular characteristics from those of the American type strain.

• 생약학회지
• /
• 제33권1호통권128호
• /
• pp.13-17
• /
• 2002

Helicobacter pylori infection is associated with type B gastritis, peptic ulcer, and gastric cancer. The vacuolation of cells induced by H. pylori is thought to be essential for the initiation and maintenance of gastric infection. The roles of H. pylori cytotoxin, urease, and ammonia in the vacuolation of HeLa cells were determined. Ammonium chloride augmented the neutral red uptake induced by H. pylori toxin. Acetohydroxamic acid (AHA) failed to block the neutral red uptake induced by H. pylori toxin. Leweifang significantly prevented the vacuolation of HeLa cells induced by H. pylori toxin or H. pylori toxin and ammonium chloride. Further investigation is required to determine the mechanisms of Leweifang for the inhibition of vacuole formation of eukaryotic cells in response to the H. pylori toxin.

• 한국식품영양학회지
• /
• 제28권1호
• /
• pp.60-65
• /
• 2015

버섯은 우리나라에서 식용으로 널리 이용되고 있는 식품으로 많은 연구들에서 다양한 생리활성 효과에 대한 연구가 활발하게 이루어지고 있다. 본 연구는 다양한 버섯 중에서 최근 많이 이용되고 있는 느타리버섯 추출물을 이용하여 항산화 활성 및 세포 독성 효과를 확인하고자 하였다. 연구결과, 느타리버섯의 총 폴리페놀 함량과 플라보노이드 함량은 각각 $30.2{\pm}0.7mg%$와 $20.4{\pm}0.6mg%$로 나타났다. 0.625, 1.25, 2.5, 5 mg/mL 농도에서의 DPPH radical 소거능은 0.625의 농도에서 $4.5{\pm}0.1%$, 1.25의 농도에서 $11.0{\pm}0.4%$, 2.5 mg/mL 농도에서 $23.2{\pm}0.1%$, 5.0 mg/mL 농도에서 $44.1{\pm}0.6%$의 결과를 보였다. 환원력은 5 mg/mL의 농도에서 $1.648{\pm}0.047$로 가장 높은 환원력을 보여주어 시료의 농도가 증가할수록 흡광도 값도 증가하여 높은 환원력을 나타내었다. 느타리버섯 물 추출물의 인간 정상 신장세포 HEK293을 이용한 정상세포에 대한 세포 독성을 측정한 결과에서는 느타리버섯 물 추출물 80.5%의 생존력을 나타내어 독성이 없는 것으로 보였다. 한편, 이들 버섯 추출물의 암세포 성장 억제에 미치는 영향을 검색한 간암세포 생육 저해능의 결과는 최고 5 mg/mL의 농도에서 $70.0{\pm}5.3%$의 세포 생존력을 나타내어, 암세포 성장에는 영향을 미치지 못하는 것으로 사료된다.

• 한국식품위생안전성학회:학술대회논문집
• /
• 한국식품위생안전성학회 2001년도 The Asia-Pacific Conference on Reproductive Biology and Environmental Sciences
• /
• pp.162-162
• /
• 2001

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.228.1-228.1
• /
• 2002

Hypoxia in solid tumors is known to contribute to intrinsic chemoresistance. Tirapazamine(TPZ). a hypoxia-selective cytotoxin. showed synergism with radiation or cytotoxic agents. Paclitaxel(PTX) is a highly active anti-cancer agent against Non small cell lung cancer(NSCLC), however. due to poor penetration into central hypoxic region of tumor tissue. combination with TPZ has been suggested to enhance its efficacy. (omitted)

• 한국식품위생안전성학회:학술대회논문집
• /
• 한국식품위생안전성학회 2001년도 The Asia-Pacific Conference on Reproductive Biology and Environmental Sciences
• /
• pp.170-170
• /
• 2001

• Nutrition Research and Practice
• /
• 제11권1호
• /
• pp.11-16
• /
• 2017

BACKGROUND/OBJECTIVES: Helicobacter pylori (H. pylori) colonization of the stomach mucosa and duodenum is the major cause of acute and chronic gastroduodenal pathology in humans. Efforts to find effective anti-bacterial strategies against H. pylori for the non-antibiotic control of H. pylori infection are urgently required. In this study, we used whey to prepare glycomacropeptide (GMP), from which sialic acid (G-SA) was enzymatically isolated. We investigated the anti-bacterial effects of G-SA against H. pylori in vitro and in an H. pylori-infected murine model. MATERIALS/METHODS: The anti-bacterial activity of G-SA was measured in vitro using the macrodilution method, and interleukin-8 (IL-8) production was measured in H. pylori and AGS cell co-cultures by ELISA. For in vivo study, G-SA 5 g/kg body weight (bw)/day and H. pylori were administered to mice three times over one week. After one week, G-SA 5 g/kg bw/day alone was administered every day for one week. Tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), IL-$1{\beta}$, IL-6, and IL-10 levels were measured by ELISA to determine the anti-inflammatory effects of G-SA. In addition, real-time PCR was performed to measure the genetic expression of cytotoxin-associated gene A (cagA). RESULTS: G-SA inhibited the growth of H. pylori and suppressed IL-8 production in H. pylori and in AGS cell co-cultures in vitro. In the in vivo assay, administration of G-SA reduced levels of IL-$1{\beta}$ and IL-6 pro-inflammatory cytokines whereas IL-10 level increased. Also, G-SA suppressed the expression of cagA in the stomach of H. pylori-infected mice. CONCLUSION: G-SA possesses anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect in an experimental H. pylori-infected murine model. G-SA has potential as an alternative to antibiotics for the prevention of H. pylori infection and H. pylori-induced gastric disease prevention.