• BMB Reports
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• 제28권3호
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• pp.221-226
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• 1995

Dopamine mediates inhibitory responses in Helix aspersa neurons from the right parietal lobe ("F-lobe") of the circumoesophageal ganglia. The effects appeared as a dose-dependent hyperpolarization of the plasma membrane and a decrease in the occurrence of spontaneous action potentials. The average hyperpolarization with 5 ${\mu}m$ dopamine was -12 mV (${\pm}1.5$mV, S.D., n=12). Dopamine also modulated the currents 'responsible for shaping the action potentials in these neurons. When dopamine was added and action potentials were triggered by an injection of current, the initial depolarization was slowed, the amplitude and the duration of action potentials were decreased, and the after-hyperpolarization was more pronounced. The amplitude and the duration of action potential were reduced about 15 mV and about 13% by 5 ${\mu}m$ dopamine, respectively. The effects of dopamine on the resting membrane potentials and the action potentials of Helix neurons were dose-dependent in the concentration range 0.1 ${\mu}m$ to 50 ${\mu}m$. In order to show 1) that the effects of dopamine were mediated by dopamine receptors rather than by direct action on ionic channels and 2) which type of dopamine receptor might be responsible for the various effects, we assayed the ability of mammalian dopamine receptor antagonists, SCH-23390 (antagonist of D1 receptor) and spiperone (antagonist of D2 receptor), to block the dopamine-dependent changes. The D1 and D2 antagonists partially inhibited the dopamine-dependent hyperpolarization and the decrease in action potential amplitude. They both completely blocked the decrease in action potential duration and the increase in action potential after-hyperpolarization. The dopamine-induced slowdown of the depolarization in the initial phase of the action potentials was less effected by SCH-23390 and spiperone. From the results we suggest 1) that Helix F-lobe neurons may have a single type of dopamine receptor that binds both SCH-23390 and spiperone and 2) that the dopamine receptor of Helix F-lobe neurons may be homologous with and primitive to the family of mammalian dopamine receptors.

• 한국항공우주학회지
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• 제42권11호
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• pp.981-987
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• 2014

DC/DC 컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시키는 효율이 높은 전력변환기이다. DC/DC 컨버터는 MOSFET(산화물-반도체 전계 효과 트랜지스터), PWM-IC(펄스폭 변조 집적회로) 제어기, 인덕터, 콘덴서 등으로 구성되어있다. MOSFET는 스위치 기능을 수행하는데 코발트 60 ($^{60}Co$) 저준위 감마발생기를 이용한 TID 실험에서 방사선의 영향으로 문턱전압과 항복전압의 변화와 SEGR 실험에 적용된 5종류의 중이온 입자는 MOSFET의 게이트(gate)에 영향을 주어 게이트가 파괴된다. MOSFET의 TID 실험은 40 Krad 까지 수행하였으며, SEGR 실험은 제어보드를 구현한 후 LET(MeV/mg/$cm^2$)별 cross section($cm^2$)을 연구하는데 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2939-2946
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• 2015

Many of the anti-cancer agents currently used have an origin in natural sources including plants. Aloe vera is one such plant being studied extensively for its diverse health benefits, including cancer prevention. In this study, the cytotoxic potential of Aloe vera crude extract (ACE) alone or in combination with cisplatin in human breast (MCF-7) and cervical (HeLa) cancer cells was studied by cell viability assay, nuclear morphological examination and cell cycle analysis. Effects were correlated with modulation of expression of genes involved in cell cycle regulation, apoptosis and drug metabolism by RT-PCR. Exposure of cells to ACE resulted in considerable loss of cell viability in a dose- and time-dependent fashion, which was found to be mediated by through the apoptotic pathway as evidenced by changes in the nuclear morphology and the distribution of cells in the different phases of the cell cycle. Interestingly, ACE did not have any significant cytotoxicity towards normal cells, thus placing it in the category of safe chemopreventive agent. Further, the effects were correlated with the downregulation of cyclin D1, CYP 1A1, CYP 1A2 and increased expression of bax and p21 in MCF-7 and HeLa cells. In addition, low dose combination of ACE and cisplatin showed a combination index less than 1, indicating synergistic growth inhibition compared to the agents applied individually. In conclusion, these results signify that Aloe vera may be an effective anti-neoplastic agent to inhibit cancer cell growth and increase the therapeutic efficacy of conventional drugs like cispolatin. Thus promoting the development of plant-derived therapeutic agents appears warranted for novel cancer treatment strategies.

• Journal of Ginseng Research
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• 제31권1호
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• pp.34-43
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• 2007

Background: Previous research has suggested that single doses of a standardised Panax ginseng extract can decrease fasted blood-glucose levels and modulate cognitive performance in healthy young volunteers. The latter has generally been seen in terms of improved secondary memory performance. However, both the cognitive effects of chronic administration of ginseng and the potential modulation of working memory have received comparatively little research attention. Aims: The current double-blind, placebo-controlled, balanced cross-over study investigated the effects of 8-weeks administration of Korean ginseng extract (200 mg) on cognitive performance, gluco-regulatory parameters and ratings of subjective mood and 'quality of life'. Methods: 'Eighteen healthy young participants were assessed pre-dose and 3 hours post-dose on the mornings of Day 1, Day 29 and Day 57 of 8 week treatment regimens of both placebo and ginseng. A four-week placebo wash-out separated the treatment phases. Each assessment included the Cognitive Drug Research battery, computerised working memory tasks, and Bond-Lader mood scales. The WHO Quality of Life scale (WHOQOL-BREF) was completed once per visit. Gluco-regulatory parameters were assessed with assays of blood glucose, insulin and HbA1c. Results: Data from the 16 participants that completed the study showed that there were no significant, acute treatment related differences on Day 1 of treatment, or in gluco-regulatory parameters throughout the study. However, time related performance improvements were evident following chronic administration of ginseng on the '3-Back' and 'Corsi-block' computerised working memory tasks. Ginseng was also associated with an improved score on the 'social relations' subscale of the WHOQOL-100, and a significant shift on the 'calm' factor of the Bond-Lader mood scales (from calm/relaxed towards excited/tense). Conclusion: The results of the current study suggest that Korean ginseng extract can modulate working memory performance and subjective ratings of 'quality of life' and mood. Replication with a larger sample size may further elucidate the actions of this product.

• 대한한의학방제학회지
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• 제28권1호
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• pp.63-70
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• 2020

Objectives : The purpose of this study was to investigate the anti-cancer effects of 18α-Glycyrrhetinic acid (18α-GA), a hydrolyzed metabolite of glycyrrhizin, in AGS human gastric adenocarcinoma cells. Methods : We used human gastric adenocarcinoma cell line, AGS cells. We examined cell death by MTT assay and caspase 3 and 9 assay with 18α-GA. To examine the inhibitory effects of 18α-GA, sub-G1 analysis was done the AGS cells after 24 hours with 18α-GA. Also, to investigate the inhibitory mechanisms of 18α-GA, mitogen-activated protein kinase pathways and reactive oxygen species (ROS) generation were examined. Results : 1. 18α-GA inhibited the growth of AGS cells in a dose-dependent fashion. 2. Sub-G1 fractions were significantly and dose-dependently increased by 18α-GA. 3. 18α-GA increased the caspase 3 and 9 activities in AGS cells. 4. 18α-GA inhibited proliferation of AGS cells via the modulation of c‑Jun N‑terminal kinase (JNK) signaling pathways, which results in the induction of apoptosis. 5. 18α-GA enhanced ROS accumulation in AGS cells. Conclusions : Our findings provide insight into unraveling the effects of 18α-GA in human gastric adenocarcinoma cells and developing therapeutic agents against gastric cancer.

• BMB Reports
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• 제33권6호
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• pp.469-475
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• 2000

The purpose of this study was to examine the chemopreventive potential of taurine at various levels on the diethylnitrosamine (DEN)·induced hepatocarcinogenesis. Male Sprague-Dawley rats were fed on diets containing 0, 1, 2, 3% taurine or 5% ${\beta}-alanine$ for taurine depletion. Then they were treated with DEN and 2/3 partial hepatectomy. The number of placental glutathione S-transferase positive ($GST-P^+$) foci, as a preneoplastic marker in the 1 % taurine group was lower than the control diet group. However the difference was insignificant. Although taurine diets reduced the thiobarbituric acid reactive substance (TBARS) level, the number of $GST-P^+$ foci was increased in 3% taurine diet group. The 1 % taurine diet increased the glutathione (GSH) level and GST activity, however they unfortunately did not suppress the foci formation. In the 3% taurine group, the GSH level and GSH peroxidase (GPx) activity were significantly decreased. Excess taurine supplementation of the pharmaceutical dose worked against hepatic chemoprevention, which might result from modulation of GPx activity and GSH utility. On the contrary, taurine might work as an antioxidant against TBARS production as the 1 % taurine diet increased GSH level. The potency of the cancer preventive effect of taurine still remains and further studies should investigate the effect of taurine with less than 1 % levels on the prevention of hepatic cancer.

• 동의생리병리학회지
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• 제21권4호
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• pp.1017-1024
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• 2007

Thymus and activation-regulated chemokine (TARC/CCL-17), produced by keratinocytes, is a CC chemokine known to selectively Th2 type T cells via $CCR4^+$ and is implicated in the development of atopic dermatitis (AD). TARC/CCL17 expression was induced by cytokines such as tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interferon-${\gamma}$ (IFN-${\gamma}$). We recently found that the wogonin, a flavone isolated from Scutellaria baicalensis, suppressed TARC expression via heme oxygenase 1 (HO1) in human keratinocytes induced with mite antigen. However, little is known about the inhibitory mechanism of wogonin on TARC/CCL-17 expression stimulated with cytokines. To investigate the inhibitory mechanism, I determined the inhibitory effects of wogonin on the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and $I{\kappa}B{\alpha}$ phosphorylation, and also examined the activation of p38 MAP kainase in HaCaT keratinocytes stimulated with TNF-${\alpha}$ and IFN-${\gamma}$. Wogonin inhibited NF-${\kappa}B$-DNA complex, NF-${\kappa}B$ binding activity, and the phosphorylation of $I{\kappa}B{\alpha}$ in a dose dependent manner. Wogonin also inhibited the translocation of NF-${\kappa}B$ from cytosol to nucleus. Moreover, the phosphorylation of of p38 MAP kinase in the TNF-${\alpha}$ and IFN-${\gamma}$-stimulated HaCaT keratinocytes were suppressed by wogonin in a dose dependent manner. These results suggest that wogonin may inhibit cytokine-induced NF-${\kappa}B$ activation by $I{\kappa}B{\alpha}$ degradation via suppression of p38 MAP kinase signaling pathway in keratinocytes and modulation of wogonin signaling pathway may be beneficial for the treatment of AD.

• IMMUNE NETWORK
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• 제11권6호
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• pp.383-389
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• 2011

Background: EY-6 is one of the newly synthesized indoledione derivatives to induce tumor cell-specific cell death. In this study, we investigated the mechanism of immunological death induced by EY-6 at mouse colon cancer cell as well as at the normal immune cell represented by dendritic cell. Methods: C57BL/6 mouse syngeneic colon cancer cell MC38 was treated with EY-6, and analyzed by MTT for viability test, flow cytometry for confirming surface expressing molecules and ELISA for detection of cytokine secretion. Normal myeloid-dendritic cell (DC) was ex vivo cultured from bone marrow hematopoietic stem cells of C57BL/6 mice with GM-CSF and IL-4 to analyze the DC uptake of dead tumor cells and to observe the effect of EY-6 on the normal DC. Results: EY-6 killed the MC38 tumor cells in a dose dependent manner (25, 50 and $100{\mu}M$) with carleticulin induction. And EY-6 induced the secretion of IFN-${\gamma}$ but not of TNF-${\alpha}$ from the MC38 tumor cells. EY-6 did not kill the ex-vivo cultured DCs at the dose killing tumor cells and did slightly but not significantly induced the DC maturation. The OVA-specific cross-presentation ability of DC was not induced by chemical treatment (both MHC II and MHC I-restricted antigen presentation). Conclusion: Data indicate that the EY-6 induced tumor cell specific and immunological cell death by modulation of tumor cell phenotype and cytokine secretion favoring induction of specific immunity eliminating tumor cells.

• Asian-Australasian Journal of Animal Sciences
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• 제32권10호
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• pp.1548-1557
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• 2019

Objective: To investigate the effects of dietary supplementation with different levels and molecular weights of fungal ${\beta}$-glucan on productive performances, health, carcass traits and meat quality in broilers. Methods: Two hundred and ten of one-day-old chicks with equal sex were assigned to seven experimental groups in $2{\times}4$ factorial arrangement. These groups were supplemented with (0, 10, 30, and 60 ppm) of molecular weight 1-3, 1-6 ${\beta}$-glucan (low or high). High molecular weight ${\beta}$-glucan (H: 943 kDa) was obtained from Ophiocordyceps dipterigena BCC 2073, whereas H with ${\gamma}$-Irradiation treatment was performed to achieve low molecular weight ${\beta}$-glucan (L: 8 kDa). Results: There was no statistical significance in productive performances, apparent digestibility and interaction between fixed factors along 42 days of experiment (p>0.05). A higher caecal amylase activity was present in the group that received L, while there was a dramatic decrease in H and the control groups, respectively (p<0.05). The increase of supplemental dose increased caecal amylase activity (p<0.05). Immunomodulatory effects from L was revealed by the marked increase of phagocytic activity, relative weight of thymus and bursa of fabricius (p<0.05). Similarly, the additive dose at 30 ppm provided the same results, whereas the only significant difference with supplementation at 60 ppm was an increase in phagocytic activity (p<0.05). Interestingly, villi height of broilers fed L was higher than other groups (p<0.05). The treatments did not influence haematology, blood chemistry, antibody production level against vaccination, carcass traits and meat quality (p>0.05). Conclusion: The supplementation of L at 30 ppm was suggested to achieve benefits of immune modulation without adverse effects on other parameters.

• 대한통합의학회지
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• 제8권4호
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• pp.163-169
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• 2020

Purpose : This study aimed to investigate the anti-allergic effect of Persicaria perfoliata water extract (PPWE) on IgE stimulated rat basophilic leukemia (RBL-2H3) cell line. Methods : P. perfoliata (L.) H. Gross has been used in traditional medicine as an anti-allergic agent, antipyretic, and diuretic and for respiratory disorders. To analyze the anti-allergic activity of PPWE, release of β-hexosaminidase in RBL-2H3 cells was estimated by enzyme linked immunosorbant assay (ELISA). Also, the cytotoxic effect of PPWE was identified by WST assay, and nuclear factor (NF)-κB and its upstream signaling molecules were assessed by western blot analysis. Results : PPWE treatment significantly attenuated β-hexosaminidase release in a dose dependent manner without any cytotoxicity. PPWE inhibited β-hexosaminidase activity by 38.4±1.2, 36.6±0.6, 32.5±2.2 and 26.5±1.2 at 500, 250, 100, and 50 ㎍/㎖ of PPWE, respectively, compared with the control group. In addition, an analysis of the expression level of NF-κB, an inflammation transcription factor, in RBL-2H3 cells upon IgE stimulation provided reults consistent with the results of β-hexosaminidase release. The phosphorylated status of upstream signaling molecules for transcription factor, mitogen activated protein kinases (MAPKs), was also analyzed. The results showed that PPWE treatment dose-dependently inhibited phosphorylation of extracellular regulatory kinase (ERK) and c-Jun N-terminal kinase (JNK). These results show that PPWE had a strong IgE-mediated degranulation inhibitory effect on RBL-2H3 cells. Conclusion : P. perfoliata ameliorated IgE-mediated allergic reaction via the modulation of MAPK and NF-κB signaling pathway in RBL-2H3 cells. These results indicate that P. perfoliata could be a potential candidate for a treatment strategy against various allergic disorders.