• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.350-355
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• 2004

Sulforhodamine B (SRB) assay is a rapid, sensitive, and inexpensive method for measuring cell proliferation and chemosensitivity. However, the lactate dehydrogenase (LDH) release assay is generally used to measure cytototoxicity of infectious microorganisms against host cells. In this study, we investigated the possibility of applying the SRB assay to determine cytotoxicity for infectious microorganisms, and compared the results with those obtained by the LDH release assay. We used Vibrio vulnificus as a model of infectious microorganisms. The SRB assay showed that V vulnificus strongly induced cytotoxic activity against human intestinal cells, Caco-2 and INT-407 cells. The degree of cytotoxicity closely correlated with infection time and number ratios of V. vulnificus to intestinal cells (MOI, multiplicity of infection). Furthermore, cytotoxicity values obtained by SRB assay correlated well with results obtained by the LDH release assay, and both assays gave a linear response with respect to MOI Heat-inactivation of V. vulnificus for 35 min at $60^{\circ}C$ did not induce cytotoxic activity, indicating that viability of V. vulnificus is crucial for cytotoxic activity against intestinal cells. Although both assays are suitable as cytotoxicity endpoints, the SRB assay is recommended for measuring cytotoxicity of infectious microorganisms against host cells because of its significantly lower cost and more stable endpoint than the LDH release assay.

• 대한인간공학회지
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• 제17권1호
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• pp.115-123
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• 1998

We study the ski wear which are compared at the materials and the designes and their human physiological and phychological response during exercise in a cold and air-conditioned enviroments. Five men exercises in the experiment room with four types of ski-wears : two of one-piece and two of two-piece : two of special material and two of a normal material, respectively. We keep the environment at $-5^{\circ}C$ and speed of 3.6 mile/hr during the measurement of 13 points, which is a mean model of the Muju ski-resort at January 1996. We conclude the followings : 1. The ski-wear with special materials have higher than the normal type at mean skin temperature and rectal temperature. 2. Changes of temperature withing the clothes during the exercise is small, but the humidity within the clothes abruptly increases because of the weight loss. 3. Type A ski-wear with the special material has $295.5g/m^2hr$ weight loss, which is higher, and type D ski-wear is smaller 4. The special material shows comfortable in the thermal sensation. 5. In the design aspect of the ski-wears, the two-piece type ski-wear shows higher skin temperature and temperature & humidity within the clothes than the one-piece type due to the effect of the multiplicity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.515-522
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• 2001

A simplified method is presented for the computation of eigenvalue and eigenvector derivatives associated with repeated eigenvalues. In the proposed method, adjacent eigenvectors and orthonormal conditions are used to compose an algebraic equation whose order is (n+m)x(n+m), where n is the number of coordinates and m is the number of multiplicity of the repeated eigenvalue. One algebraic equation developed can be computed eigenvalue and eigenvector derivatives simultaneously. Since the coefficient matrix of the proposed equation is symmetric and based on N-space, this method is very efficient compared to previous methods. Moreover the numerical stability of the method is guaranteed because the coefficient matrix of the proposed equation is non-singular, This method can be consistently applied to both structural systems with structural design parameters and mechanical systems with lumped design parameters. To verify the effectiveness of the proposed method, the finite element model of the cantilever beam and a 5-DOF mechanical system in the case of a non-proportionally damped system are considered as numerical examples. The design parameter of the cantilever beam is its width, and that of the 5-DOF mechanical system is a spring.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.721-726
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• 2004

A simplified method for the computation of first second and higher order derivatives of eigenvalues and eigenvectors derivatives associated with repeated eigenvalues is presented. Adjacent eigenvectors and orthonormal conditions are used to compose an algebraic equation whose order is (n+m)x(n+m), where n is the number of coordinates and m is the number of multiplicity of the repeated eigenvalues. The algebraic equation developed can be used to compute derivatives of both eigenvalues and eigenvectors simultaneously. Since the coefficient matrix in the proposed algebraic equation is non-singular, symmetric and based on N-space it is numerically stable and very efficient compared to previous methods. This method can be consistently applied to structural systems with structural design parameters and mechanical systems with lumped design parameters. To verify the effectiveness of the proposed method, the finite element model of the cantilever beam is considered.

• 한국식품영양과학회지
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• 제41권4호
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• pp.462-470
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• 2012

본 연구의 결과, TPA 종양촉진 시작과 함께 실험식이를 급여하였을 때, 장뇌삼은 대조군과 인삼군보다 낮은 피부종양발생수를 나타내었으며 종양발생률에서도 대조군과 인삼군에 비해 장뇌삼군에서 종양의 발생이 지연되는 것으로 나타났다. 반면, DMBA 종양개시 한 달 전부터 실험 종료 시까지 실험식이를 급여하였을 때는 대조군과 장뇌삼군에 비해 인삼군의 종양발생수가 감소된 것으로 나타나 인삼은 암 예방효능이 장뇌삼보다 더 높은 것으로 나타났다. 장뇌삼과 인삼은 마우스 피부암이 아닌 다른 상피세포성 암에 대해서도 각각 이러한 효능을 보일 것인지에 대해서 후속연구가 요구되며 또한 앞으로 인삼과 장뇌삼의 유효성분을 발굴하고 이를 더욱 효과적으로 섭취할 수 있는 방법이 개발되어야 할 것으로 생각된다. 아울러 질적으로 우수한 우리나라 장뇌삼과 인삼이 건강기능식품으로서 뿐만 아니라 암 예방과 암치료에 사용될 수 있는 대체의약품으로 개발되기 위해서는 실질적인 임상치료 연구와 더불어 보다 구체적인 과학적 기능 규명연구가 필요하다고 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4435-4440
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• 2013

Aloe vera gel supercritical $CO_2$ extract (AVGE) has been shown to contain five phytosterols, reduce visceral fat accumulation, and influence the metabolism of glucose and lipids in animal model experiments. Recent epidemiologic studies have shown that obesity is an established risk factor for several cancers including colorectal cancer. Therefore, we examined the effects of AVGE on intestinal polyp formation in Apc-deficient Min mice fed a high-fat diet. Male Min mice were divided into normal diet (ND), high fat diet (HFD), low dose AVGE (HFD+LAVGE) and high dose AVGE (HFD+HAVGE) groups. The ND group received AIN-93G diet and the latter 3 groups were given modified high-fat AIN-93G diet (HFD) for 7 weeks. AVGE was suspended in 0.5% carboxymethyl cellulose (CMC) and administered orally to mice in HFD+LAVGE and HFD+HAVGE groups every day (except on Sunday) for 7 weeks at a dose of 3.75 and 12.5 mg/kg body weight, respectively. ND and HFD groups received 0.5% CMC alone. Between weeks 4 and 7, body weights in the HFD and HFD+LAVGE groups were reduced more than those in the ND group. However, body weights were not reduced in the HFD+HAVGE group. Mice were sacrificed at the end of the experiment and their intestines were scored for polyps. No significant differences were observed in either the incidence and multiplicity of intestinal polyps (${\geq}0.5$ mm in a diameter) among the three groups fed HFD. However, when intestinal polyps were categorized by their size into 0.5-1.4, 1.5-2.4, or ${\geq}2.5$ mm, the incidence and multiplicity of large polyps (${\geq}2.5$ mm) in the intestine in the HFD+HAVGE group were significantly lower than those in the HFD group. We measured plasma lipid (triglycerides and total cholesterol) and adipocytokine [interleukin-6 and high molecular weight (HMW) adiponectin] levels as possible indicators of mechanisms of inhibition. The results showed that HMW adiponectin levels in the HFD group were significantly lower than those in the ND group. However, the levels in the HFD+HAVGE group were significantly higher than those in the HFD group. These results indicate that HAVGE reduced large-sized intestinal polyps and ameliorated reduction in plasma HMW adiponectin levels in Min mice fed HFD.

• 한국산림과학회지
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• 제100권1호
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• pp.70-78
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• 2011

본 연구에서는 국내 과거 산불 자료를 기초로 하여 계절별 산불 발생 확률 시뮬레이션 모델을 개발하였다. 산불 발생 확률 모델은 산불 발생 사건의 시간적 분포가 과거 자료와 부합해야 하므로, 세 단계를 거쳐 생성하였다. 먼저, 산불 기간 중의 산불 발생 일은 베르누이 분포에서 임의로 추출하여 일일 단위로 산불의 발생 여부를 결정하였다. 다음 단계로, 산불이 발생하면 기하학적 다중 분포에서 임으로 추출하여 그 날 하루 중에 발생하는 산불의 수를 결정하였다. 마지막 단계로, 각 산불의 발화 시간은 포아송 분포를 가정하여 하루 중 산불 발생이 가능한 시간중 임의로 추출하여 결정하였다. 산불 발생의 확률적 분포는 과거 산불 발생 자료를 바탕으로 추정하였다. 확률 분포에 대한 중요 계수 값을 구하기 위해 최우도추정법을 이용하였다. 개발된 확률 시뮬레이션 모델에 의해 생성된 일련의 산불 발생 사건들은 과거 산불 통계 자료와 비교할 때 발생 주기 분포, 산불간의 시간 간격, 연간 일어나는 산불 총 건수에서 통계적으로 부합하는 것으로 나타났다. 본 연구의 결과는 향후 산불 관련 자원 활용 및 진화 계획 수립 시에 중요한 보조 자료로 활용될 것으로 기대된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5331-5339
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• 2013

Colorectal cancer is one of the leading causes of cancer death, both in men and women. This study investigated the effects of Amorphophallus campanulatus tuber methanolic extract (ACME) on aberrant crypt foci (ACF) formation, colonic cell proliferation, lipid peroxidative damage and the antioxidant status in a long term preclinical model of 1, 2-dimethylhydrazine (DMH) induced colon carcinogenesis in rats. Male Wistar rats were divided into six groups, viz., group I rats served as controls; group II rats treated as drug controls receiving 250 mg/kg body weight of ACME orally; group III rats received DMH (20 mg/kg body weight) subcutaneously once a week for the first 15 weeks; groups IV, V and VI rats received ACME along with DMH during the initiation, post-initiation stages and the entire period of the study, respectively. All the rats were sacrificed at the end of 30 weeks and the intestinal and colonic tissues from different groups were subjected to biochemical and histological studies. Administration of DMH resulted in significant ($p{\leq}0.05$) intestinal and colonic lipid peroxidation (MDA) and reduction of antioxidants such as catalase, glutathione peroxidase, glutathione reductase, glutathione-Stransferase and reduced glutathione. Whereas the supplementation of ACME significantly ($p{\leq}0.05$) improved the intestinal and colonic MDA and reduced glutathione levels and the activities of antioxidant enzymes in DMH intoxicated rats. ACME administration also significantly suppressed the formation and multiplicity of ACF. In addition, the DMH administered rats showed amplified expression of PCNA in the colon and decreased expression of this proliferative marker was clearly noted with initiation, post-initiation and entire period of ACME treatment regimens. These results indicate that ACME could exert a significant chemopreventive effect on colon carcinogenesis induced by DMH.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1115-1118
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• 2012

Diallyl sulfide (DAS), a flavoring compound derived from garlic, is considered to have cancer chemopreventive potential in experimental animals and humans. This study was designated to examine possible chemopreventive effects of DAS on colon carcinogenesis using genetically engineered transgenic $Apc^{Min/+}$ mice, a well-established animal model for familial adenomatous polyposis (FAP) and sporadic colorectal cancer. Male C57BL/6J-$Apc^{Min/+}$ mice were divided into three groups. Animals of group 1 were placed on the basal diet (AIN-76A) as non-treated controls. Animals of groups 2 and 3 were given DAS-containing diets (in doses of 100 and 300 ppm, respectively). All mice were sacrificed at the end of week 10 of the experiment. Histopathological investigation revealed that the incidence of colonic polyps was decreased dose-dependently by 19% (13/16) in group 2 and by 32% (13/20) in group 3 compared to the 100% incidence (10/10) in group 1. The multiplicity of colonic polyps per mouse was also slightly decreased by DAS treatment ($1.88{\pm}0.35$ in group 2 and $1.63{\pm}0.36$ in group 3) compared to $2.00{\pm}0.39$ in group 1. On the other hand, there were no significant differences in the numbers of total polyps per mouse in the small intestine between the groups. Taken together, we suggest that DAS may exert promising inhibitory effects on colon carcinogenesis in the transgenic $Apc^{Min/+}$ mice.

• 대한수의학회지
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• 제54권3호
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• pp.171-177
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• 2014

Garlic and mugwort have long been used in traditional medicine to prevent various diseases. Several in vitro studies have reported protective efficacies of garlic and mugwort in cases of gastric cancer. In the present study, we investigated the cancer preventive effects of garlic and mugwort mixture extract (GME) in a Helicobacter (H.) pylori-associated gastric carcinogenesis mouse model. To induce gastric cancer, C57BL/6 mice were treated with N-methyl-N-nitrosourea and H. pylori. Various concentrations of GME (0, 100, 500, and 1,000 ppm) were then fed to the mice for 38 weeks, after which the tumor tissues were examined for histopathology, mucin histochemistry and ${\beta}$-catenin. The incidence of gastric tumors was significantly lower in the highest dose GME-treated mice (46.7%) than control mice (85.7%) (p < 0.05). The multiplicity and size of tumors were also significantly reduced by GME feeding in a dose-dependent manner (p < 0.01). Furthermore, GME suppressed the H. pylori-associated chronic inflammation measured by histologic grading of H. pylori density, chronic gastritis, glandular atrophy and intestinal metaplasia in non-tumorous gastric mucosae. Our data suggest that GME suppresses gastric tumorigenesis via suppression of H. pylori-associated chronic inflammation.