검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 123

        84.
        2012.06 구독 인증기관 무료, 개인회원 유료
        Iron is an essential trace element for normal functions of the body. Restriction of iron availability directly limits erythropoiesis. The objective of this experiment was to compare the bioavailability of iron nanoparticles (Fe-NPs) with iron-microparticles (Fe-MPs) in anemic mice. There were four experimental groups, including the normal control group, iron-deficiency anemia (IDA) group, Fe-NPs group, and Fe-MPs group. Animals in the normal group fed on an adequate iron-containing diet (45 ppm Fe). Meanwhile, animals in the other three groups fed on a low Fe diet (4.5 ppm Fe) for seven weeks. Double deionized water was supplied as drinking water ad libitum. After feeding for three weeks with the low Fe diet, animals in the Fe-NPs and Fe-MPs groups received oral administration of Fe-NPs or Fe-MPs at a daily dose of 40 mg/kg for four weeks. The IDA group showed markedly decreased red blood cell (RBC) count, hematocrit (Hct), and hemoglobin (Hb) values compared with the normal group throughout the experimental periods. Treatments with Fe-NPs or Fe-MPs for four weeks resulted in restoration of the decreased RBC count and hematological values similar to normal values. The Fe-NPs group showed faster restoration in values than Fe-MPs with passage of time. The iron contents of the upper small intestine in the Fe-NPs and Fe-MPs groups were higher than in the normal group at weeks 2 and 4. Treatment with Fe-NPs and Fe-MPs resulted in a significant increase in hepatic iron contents and lipid peroxidation, compared with the IDA group with passage of time. The iron contents in liver and ferritin deposits in spleen were identified in the Fe-NPs and Fe-MPs groups, similar to the normal group. These results indicate that oral administration of both Fe-NPs and Fe-MPs can result in recovery from anemia and Fe-NPs is more absorbable and available in the body than Fe-MPs.
        4,600원
        85.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hemorrhagic Escherichia coli (E. coli) is one of the most important agent of diarrhea in piglet. The aim of this study was to investigate the characteristics of virulence genes and genetic diversity in hemorrhagic E. coli isolated from piglets with diarrhea. Among 122 hemorrhagic E. coli, 62 isolates carried single toxin gene like heat-stable toxin (ST), heatlabile toxin (LT), verotoxin 1 (VT1), verotoxin 2 (VT2), spa and eae. The most prevalent toxin gene carried by isolates was ST gene (23 isolates), while the most common association was ST/LT (14 isolates) and ST/LT/VT2 (13 isolates). In pulsed field gel electrophoresis, isolates were not classified as one cluster by epidemiological information including isolated area, isolated year and possessed toxins.
        3,000원
        86.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Both iron-deficient and zinc-sufficient diets have been known to be associated with a decreased risk of colon cancer. We investigated that effect of dietary zinc on the formation of colonic aberrant crypt foci (ACF) induced by azoxymethane (AOM) followed by dextran sodium sulfate in iron-deficient mice. Five-week old ICR mice were acclimated for 1 week and fed on iron-deficient diet (4.50 ppm iron) with three different zinc levels (0.01, 0.1, and 1.0 ppm) for 12 weeks. The total number of aberrant crypt (AC) and ACF was measured in the colonic mucosa after methylene blue staining. The total ACF numbers of low Zn (LZn), medium Zn (MZn) and high Zn (HZn) diet groups were 10.00 ± 2.67, 8.78 ± 3.12, and 7.96 ± 2.44, respectively and there were no significant differences among the groups. However, the total AC numbers of HZn (27.07 ± 3.88) and MZn (26.39 ± 5.59) diet groups were significantly low compared to LZn (22.57 ± 5.09) diet group (p<0.01). Cytosolic SOD activity was the highest in LZn diet group. But thiobarbituric acid-reactive substances level in liver was also the highest in LZn diet group compared to other groups. There is no difference in cell proliferation in mucous membrane among the groups, while apoptotic positive cells were increased in the HZn diet group. The high zinc diet exhibited decreased β-catenin-stained areas on the mucous membrane of colon compared to the LZn or MZn diet group. These findings indicate that dietary zinc might exert a modulating effect on development of ACF/AC in the mice with iron-deficient status.
        4,200원
        87.
        2012.03 구독 인증기관 무료, 개인회원 유료
        Iron nanoparticles (Fe-NPs) have recently been used for cancer diagnosis and therapy for imaging contrast and drug delivery. However, no study on nutritional bioavailability of Fe-NPs in the body has been reported. Ascorbic acid (AA) is known to aid in absorption of iron in the stomach by reducing Fe (III) to Fe (II). In this study, we investigated the bioavailability of Fe-NPs with AA in iron-deficiency-anemic mice in comparison with non-nano iron particles. Iron-deficient anemia was induced by feeding an iron-deficient diet (4.5 mg Fe/kg) and ocular bleeding from retro-orbital venous plexus for four weeks. Normal control mice were given a normal diet (45 mg Fe/ kg). After induction of anemia in mice, anemic mice received daily oral administration of Fe (40 mg/kg B.W.) + AA (5 g/kg B.W) and Fe-NPs (40 mg/kg B.W) + AA (5 g/kg B.W). After sacrifice, liver and spleen tissues were observed by haematoxylin & eosin stain. Amount of trace iron in liver and upper small intestine was investigated using an inductively coupled plasma-atomic emission spectrometer. Red blood cells (RBC), hematocrit (Hct), hemoglobin (Hb), and total iron binding capacity were also measured. The concentrations of iron in the Fe-NPs + AA group were significantly higher in liver and in upper small intestine than that in the Fe + AA group. The values of RBC, Hct, and Hb in the Fe-NPs + AA group were more rapidly increased to normal values compared with the Fe + AA group with increasing time. These results suggest that Fe-NPs in the presence of AA may be more bioavailable than non-nano Fe in Fe-deficient anemic mice.
        4,200원
        88.
        2011.06 구독 인증기관 무료, 개인회원 유료
        The current study was conducted in order to investigate promotional effects of herbal extracts on hair growth in an animal model of mice. There were four experimental groups, including distilled water (DW) as a negative control (NC), 3% minoxidil (MXD) as a positive control (PC), 50% ethanol (EtOH) as a vehicle control (VC), and herbal extract (HE) as the experimental treatment (E). The HE was extracted with ethanol from plants, including Gardenia, Mentha arvensis, Rosemary, and Lavender. Six-week-old C57BL/6 male mice were shaved with an electric clipper and the test materials were topically treated with 0.2 ml per mouse daily for three weeks. Photographic evaluation of hair re-growth was performed weekly during a period of three weeks. The number of mast cells was counted on the dorsal skin section of mice. The enzymes, alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (γ-GT), were determined using a biochemical autoanalyzer. No clinical signs were observed in any of the experimental groups. As a result of photometric analysis, topical application of HE to dorsal skin for two weeks resulted in significantly faster acceleration of hair regrowth, compared with that of the NC or VC group (P<0.05). The PC and E groups showed a significant decrease in mast cell population, compared to the NC group. Activities of ALP and γ-GT were significantly increased in the PC and E groups, compared to the NC or VC group (P<0.05). Taken together, these results suggest that the herbal extract may have hair-growth promoting activity equal to that of MXD.
        4,000원
        90.
        2011.03 구독 인증기관 무료, 개인회원 유료
        To investigate the effect of carnosine on exhaustive exercise, swimming tests were conducted weekly with loads corresponding to 5% of body weight attached to the tails of mice, and the swimming time to exhaustion was measured. Eighty male ICR mice were divided into four groups, to which carnosine was administered at doses of 0 (control), 10, 50, and 250 mg/kg/day, respectively, for a period of four weeks. At the end of swimming exercise challenges, serum biochemistry, oxidative stress enzyme activity, and antioxidant enzyme activity in tissues were determined. Treatment with 250 mg/kg carnosine resulted in a significant increase in swimming times to exhaustion, compared to the control group in the first (P<0.01) and third week (P<0.05). Significantly lower serum lactate levels were observed after the swimming exercise in the carnosine-treated groups (10 and 250 mg/kg), compared with the control (P<0.01). Malondialdehyde levels in the liver (10 and 50 mg/kg carnosine treated groups) and skeletal muscle (250 mg/kg carnosine treated group) were significantly lower, compared with the control (P<0.05). Significantly lower protein carbonyl levels in skeletal muscle were observed in the 50 and 250 mg/kg carnosine treated groups, compared with the control (P<0.01). Superoxide dismutase and glutathione peroxidase activities in skeletal muscle did not differ significantly among the groups. These results indicate that carnosine may improve swimming exercise capacity by attenuating production of lactate and reducing oxidative stress in mice.
        4,300원
        91.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 azoxymethane (AOM)과 dextran sodium sulfate (DSS)로 유도된 대장 발암과정에 대한 셀레늄의 방어 효과를 조사하였다. 셀레늄 결핍(0.02 ppm Se), 정상(0.1 ppm Se), 과다(0.5 ppm Se)사료를 12주간 식이로 급여하여 혈액검사와 대장암 발생의 초기단계인 aberrant crypt foci (ACF)수를 측정했으며, 암 발생율을 조사하였다. ICP-AES 를 사용하여 간의 셀레늄 농도를 측정하였으며, 또한 셀레늄포함 항산화효소인 glutathione peroxidase (GPx) 활성을 알아보았다. 또한 TUNEL assay와 PCNA, β-catenin에 대한 면역조직 염색을 수행하였다. ACF 수 및 종양 발생률에 있어서, 셀레늄과다사료를 급여한 군이 정상셀레늄사료를 급여한 군보다 낮았으며, 셀레늄결핍사료를 급여한 군은 오히려 ACF 수 및 종양 발생률이 높았다. GPx 활성은 셀레늄의 섭취가 과다한 군에서 높게 나타났으며, 이 때, TUNEL 에서 apoptotic positive cell이 증가하는 것을 확인했다. 또 한 셀레늄의 섭취가 과다한 군에서 PCNA와 β-catenin의 발현이 감소됨을 볼 수 있었다. 본 마우스 모델실험에서 셀레늄은 여러 기전에 의해 대장암 발생을 억제할 수 있을 것으로 사료된다.
        4,000원
        92.
        2010.05 구독 인증기관·개인회원 무료
        An expression of adult wing form in reaction to rearing density during nymphal stage was investigated in the brown planthopper, Nilaparvata lugens. Under mass rearing condition, the S-BPH and the 2007-BPH population predominantly showed a short-winged, brachypterous, form and a long-winged, macropterous, form, respectively. At rearing density of less than 5 nymphs in the 2007-BPH, 90% of females showed brachypterous form, but all males became macropterous form. The ratio of macropterous form in the 2007-BPH males decreased by 75% in 10 to 15 rearing density, but increased by more than 95% again at 20 to 30 rearing density. In the case of the 2007-BPH females, the ratio of macropterous form gradually grew from 31% at 10 nymphal density to 92% at 20 nymphal density. All females originated from the S-BPH showed brachypterous form, regardless of nymphal density. The ratio of macropterous males in the S-BPH rapidly went down from 74% at 1 nymphal density to 10% at 10 nymphal density. At 20 nymphal rearing density, all males of the S-BPH showed brachypterous form. On the other hand, other brachypterous (OJ67-BPH) and macropterous (2006-BPH) population produced similar results with above the two populations at 1 nymphal rearing density. In summary, these results demonstrate that wing form dimorphism in N. lugens is largely influenced by nymphal density and the wing form at a specific density (low or high) can be different by sex or N. lugens populations.
        94.
        2008.06 구독 인증기관 무료, 개인회원 유료
        Phytic acid (PA) is a naturallu occurring polyphosphorylated carbohydrate that is present in substantial amounts in almost all plants and mammalian cells. Recently PA has received much attention for its role in anticancer activity. We investigated the preventive effect of PA on the formation of colonic aberrant crypt foci (ACF), a preneoplastic lesion, induced by azoxymethane (AOM). After acclimation for one week, six-week old male ICR mice were fed on the AIN-93G purified diet and PA (0.5% or 2% PA in water) for 8 weeks. The animals were treated with azoxymethane (AOM, 10 mg/kg b.w.) three times (0, 1, and 2 weeks) to induce colonic aberrant crypt foci (ACF). After sacrifice, the total numbers of aberrant crypts (AC) and ACF in colonic mucosa were counted after staining with methylene blue. Blood and serum were analyzed with a blood cell differential counter and an automatic serum analyzer. AOM treatment without PA induced the total numbers of 85.7 ± 12.9 and 115.2 ± 19.9, respectively. PA at the dose of 2% AC/colon by PA at the dose of 0.5% were 73.4 ± 12.9 and 115.2 ± 19.9, respectively. PA at the dose of 2% significantly decreased the ACF and AC numbers to 56.5 ± 14.6 and 95.4 ± 17.2, respectively (p<0.01). PA at the doses of 0.5 and 2% decreased the numbers of ACF and AC/colon in a dose-dependent manner. Although some parameters in blood counts and serum chemistry were changed compared with the control, no specific toxicity was found. Theses findings suggest that phytic acid can be a chemopreventive agent for colon carcinogenesis resulting from inhibition of the development of ACF in ICR mice.
        4,000원
        100.
        1993.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We calculated the solar monopole abundance limit by comparing the observed solar neutrino flux and the calculation of non-fusion solar neutrino flux produced by Rubakov process in the solar core. We included the produced meson's enhancement effects by the surrounding ions in the solar core. We find that the monopole number N M < 1.9 × 10 20 ( 1 m b / σ 0 ) , where σ 0 is the characteristic proton decay cross section of Rubakov process. This is similar or stronger than strong limits obtained from neutron star's luminosity.
        3,000원
        1 2 3 4 5