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Effects of 20(S)-Protopanaxadiol and 20(S)-Protopanaxatriol on the Inflammatory Mediators Release from the Activated Mast Cells (20(S)-Protopanaxadiol 및 20(S)-Protopanaxatriol이 활성화된 비만세포로부터의 염증 매개체 유리에 미치는 영향)

  • Ro, Jai-Youl;Han, Yong-Nam;Choi, Kwang-Tae;Lee, Chang-Ho
    • Journal of Ginseng Research
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    • v.33 no.4
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    • pp.316-323
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    • 2009
  • Ginseng saponins have various pharmacological effects on the immune system. 20(S)-protopanaxadiol (PPD) and 20(S)-protopanaxatriol (PPT) are the species of ginseng saponin metabolites that are formed by human intestinal bacteria and detected in circulation. The effects of PPD and PPT on the inflammatory mediator release from the activated mast cells were tested. Histamine release was evaluated in activated guinea pig lung mast cells, and the secretion of interleukin-4 (IL-4), interleukin-8 (IL-8), and the tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) was assessed in an HMC-1 cell after treating it with ginseng saponin metabolites. The results are as follows. PPT, at its maximum concentration of $100\;{\mu}M$, completely abolished the secretion of IL-4 from the PMA-stimulated HMC-1 cell. It also inhibited IL-8 secretion from the same cells by about 40-50% of the PMA-treated DMSO control. PPD, at its maximum concentration of $100\;{\mu}M$, showed a tendency to induce histamine release from the guinea pig lung mast cells. It inhibited the secretion of IL-4 (by 89% of the PMA-treated DMSO control) in the PMA-stimulated HMC-1 cell, but did have a significant effect on the IL-8 release from the same cell. Both PPD and PPT showed no effects, however, on the release of TNF-${\alpha}$ from the PMA-stimulated HMC-1 cell. These results suggest that PPD and PPT are from the ginseng metabolites that are responsible for the immunomodulating activity of ginseng extracts when they are taken orally.

Amino Acid Biosynthesis and Gene Regulation in Seed (종자내 아미노산 합성 조절 유전자에 관한 연구)

  • ;;;;;Fumio Takaiwa
    • Proceedings of the Botanical Society of Korea Conference
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    • 1996.07a
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    • pp.61-74
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    • 1996
  • Human and monogastric animals can not synthesize 10 out of the 20 amino asids and therefor need to obtain these from their diet. The plant seed is a major source of dietary protein. It is particular important in their study to increase nutritional quality of the seed storage proteins. The low contents of lysine, asparagine and threonenein various cereal seeds and of cystein and methionine. In legume seeds is due to the low proportions of these amino acids in the major storage proteins, we have tried to apply the three strategies; (1) mutagenesis and selection of specific amino acid analogue resistance, (2) cloning and expression study of lysine biosynthesis related gene, (3) transfomation of lysine rich soybean glycinin gene. The 5-methyltryptophan (5MT) resistant cell lines, SAR1, SAR2 and SAR3 were selected from anther derived callus of rice (Oryza sativa L. "Sasanishiki"). Among these selected cell lines, two (SAR1 and SAR3) were able to grow stably at 200 mg/L of 5MT. Analysis of the freed amino acids in callus shows that 5MT resistant cells (SAR3) accumulated free tryptophan at least up to 50 times higher than those that of the higher than of SAS. These results indicated that the 5MT resistant cell lines are useful in studies of amino acid biosynthesis. Tr75, a rice (Oryza sativa L., var. Sasanishiki) mutant resistant to 5MT was segregated from the progenies of its initial mutant line, TR1. The 5MT resistant of TR75 was inherited in the M8 generations as a single dominant nuclear gene. The content of free amino acids in the TR75 homozygous seeds increased approximately 1.5 to 2.0 fold compared to wild-type seeds. Especially, the contents of tryptophan, phenylalanine and aspartic acid were 5.0, 5.3 and 2.7 times higher than those of wild-type seeds, respectively. The content of lysine is significantly low in rice. The lysine is synthesized by a complex pathway that is predominantly regulated by feedback inhibition of several enzymes including asparginase, aspatate kinase, dihydrodipicolinat synthase, etc. For understanding the regulation mechanism of lysine synthesis in rice, we try to clone the lysine biosynthetic metabolism related gene, DHPS and asparaginase, from rice. We have isolated a rice DHPS genomic clone which contains an ORF of 1044 nucleotides (347 amino acids, Mr. 38, 381 daltons), an intron of 587 nucleotides and 5'and 3'-flanking regions by screening of rice genomic DNA library. Deduced amino acid sequence of mature peptide domain of GDHPS clone is highly conserved in monocot and dicot plants whereas that of transit peptide domain is extremely different depending on plant specie. Southern blot analysis indicated that GDHPS is located two copy gene in rice genome. The transcripts of a rice GDHPS were expressed in leaves and roots but not detected in callus tissues. The transcription level of GDHPS is much higher in leaves indicating enormous chloroplast development than roots. Genomic DNA clones for asparaginase genes were screened from the rice genomic library by using plaque hybridization technique. Twelve different genomic clones were isolated from first and second screening, and 8 of 12 clones were analyzed by restriction patterns and identified by Southern Blotting, Restriction enzyme digestion patterns and Southern blot analysis of 8 clones show the different pattern for asparaginase gene. Genomic Southern blot analysis from rice were done. It is estimated that rice has at least 2-3 copy of asparaginase gene. One of 8 positive clones was subcloned into the pBluescript SK(+) vector, and was constructed the physical map. For transformation of lysine rich storage protein into tobacco, soybean glycinin genes are transformed into tobacco. To examine whether glycinin could be stably accumulated in endosperm tissue, the glycinin cDNA was transcriptionally fused to an endosperm-specific promotor of the rice storage protein glutelin gene and then introduced into tobacco genomic via Agrobacterium-mediated transformation. Consequently the glycinin gene was expressed in a seed-and developmentally-specific manner in transgenic tobacco seeds. Glycinin were targeted to vacuole-derived protein bodies in the endosperm tissue and highly accumulated in the matrix region of many transgenic plant (1-4% of total seed proteins). Synthesized glycinin was processed into mature form, and assembled into a hexamer in a similar manner as the glycinin in soybean seed. Modified glycinin, in which 4 contiguous methionine residues were inserted at the variable regions corresponding to the C - teminal regions of the acidic and basic polypeptides, were also found to be accumulated similarly as in the normal glycinin. There was no apparent difference in the expression level, processing and targeting to protein bodies, or accumulation level between normal and modified glycinin. glycinin.

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Toward a Social Sciences Methodology for Electronic Survey Research on the Internet or Personal Computer check (사회과학 연구에 있어 인터넷 및 상업용 통신망을 이용한 전자설문 조사방법의 활용)

  • Hong Yong-Gee;Lee Hong-Gee;Chae Su-Kyung
    • Management & Information Systems Review
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    • v.3
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    • pp.287-316
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    • 1999
  • Cyberspace permits us to more beyond traditional face-to-face, mail and telephone surveys, yet still to examine basic issues regarding the quality of data collection: sampling, questionnaire design, survey distribution, means of response, and database creation. This article address each of these issues by contrasting and comparing traditional survey methods(Paper-and-Pencil) with Internet or Personal Computer networks-mediated (Screen-and-Keyboard) survey methods also introduces researchers to this revolutionary and innovative tool and outlines a variety of practical methods for using the Internet or Personal Computer Networks. The revolution in telecommunications technology has fostered the rapid growth of the Internet all over the world. The Internet is a massive global network and comprising many national and international networks of interconnected computers. The Internet or Personal Computer Networks could be the comprehensive interactive tool that will facilitate the development of the skills. The Internet or Personal Computer Networks provides a virtual frontier to expand our access to information and to increase our knowledge and understanding of public opinion, political behavior, social trends and lifestyles through survey research. Comparable to other technological advancements, the Internet or Personal Computer Networks presents opportunities that will impact significantly on the process and quality of survey research now and in the twenty-first century. There are trade-offs between traditional and the Internet or Personal Computer Networks survey. The Internet or Personal Computer Networks is an important channel for obtaining information for target participants. The cost savings in time, efforts, and material were substantial. The use of the Internet or Personal Computer Networks survey tool will increase the quality of research environment. There are several limitations to the Internet or Personal Computer Network survey approach. It requires the researcher to be familiar with Internet navigation and E-mail, it is essential for this process. The use of Listserv and Newsgroup result in a biased sample of the population of corporate trainers. However, it is this group that participates in technology and is in the fore front of shaping the new organizations of interest, and therefore it consists of appropriate participants. If this survey method becomes popular and is too frequently used, potential respondents may become as annoyed with E-mail as the sometimes are with mail survey and junk mail. Being a member of the Listserv of Newsgroup may moderate that reaction. There is a need to determine efficient, effective ways for the researcher to strip identifiers from E-mail, so that respondents remain anonymous, while simultaneously blocking a respondent from responding to a particular survey instrument more than once. The optimum process would be on that is initiated by the researcher : simple, fast and inexpensive to administer and has credibility with respondents. This would protect the legitimacy of the sample and anonymity. Creating attractive Internet or Personal Computer Networks survey formats that build on the strengths of standardized structures but also capitalize on the dynamic and interactive capability of the medium. Without such innovations in survey design, it is difficult to imagine why potential survey respondents would use their time to answer questions. More must be done to create diverse and exciting ways of building an credibility between respondents and researchers on the Internet or Personal Computer Networks. We believe that the future of much exciting research is based in the Electronic survey research. The ability to communicate across distance, time, and national boundaries offers great possibilities for studying the ways in which technology and technological discourse are shaped. used, and disseminated ; the many recent doctoral dissertations that treat some aspect of electronic survey research testify to the increase focus on the Internet or Personal Computer Networks. Thus, scholars should begin a serious conversation about the methodological issues of conducting research In cyberspace. Of all the disciplines, Internet or Personal Computer Networks, emphasis on the relationship between technology and human communication, should take the lead in considering research in the cyberspace.

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Antimicrobial Effect of Commercially Available Mouth Rinsing Solutions and Natural Herbal Extracts on Streptococcus mutans (시판되는 구강양치액과 천연한방 추출물의 Streptococcus mutans에 대한 항균효과 비교)

  • Kim, Sung-Im;Jeong, Moon-Jin;Ahn, Yong-Soon;Kim, A-Reum;Kim, Mi-Na;Lim, Do-Seon
    • Journal of dental hygiene science
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    • v.15 no.3
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    • pp.308-317
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    • 2015
  • This study attempted to identify the possibility of natural herbal extracts as an alternative, preventive agent of caries by comparing antimicrobial activities between natural herbal extracts and mouth rinsing solutions against Streptococcus mutans. Natural herbal plants were extracted with distilled water and ethanol, respectively, to measure the minimum growth inhibitory concentration of S. mutans depending on concentration, and among which, solvents showing high antimicrobial activity were selected to compare their antibiotic effects with those of mouth rinsing solutions. Also, to determine the concentration of natural medicinal herbs that can be used safely in the oral cavity, the extracts were treated to the normal gingival fibroblast cells depending on concentration in order to determine its cytotoxicity using MTT. In terms of the minimum growth inhibition concentration, the growth inhibition of S. mutans was more excellent in the ethanol extract than in the distilled water. When the minimum growth inhibition concentration was compared, Psoralea corylifolia of natural herbal ethanol extracts, and Hexamedine (Bukwang Pharm., Korea) of mouth rinsing solutions inhibited growth of S. mutans at the lowest concentration. When the minimum bactericidal concentration was compared, P. corylifolia of natural herbal extracts, and Hexamedine and Garglin (Dong-A Pharm., Korea) of mouth rinsing solutions eliminated S. mutans at a low concentration. The human gingival fibroblast was treated with natural herbal ethanol extracts at the minimum growth inhibition concentration of 10, 39, and $78{\mu}g/ml$. As the result, no cytotoxicity was found. When this was treated at different minimum bactericidal concentrations, natural herbal ethanol extracts showed cytotoxicity except P. corylifolia.

A study on The Pulse taking diagnostics of Nan Jing 1-23 Nan (난경(難經) 1-23난중(難中) 맥학조(脈學條)에 관한 연구(硏究))

  • Kim, Bup-Jin;Park, Won-Hwan
    • The Journal of Dong Guk Oriental Medicine
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    • v.8 no.2
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    • pp.131-154
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    • 2000
  • Nan Jing(Difficult Classic), as a catechism, describes in detail and deeply the ideas in Nei Jing(Huangdi's Internal Classic). The description of Nan Jing is focused on basic theories including theories about some disease and is excellent in identification and analysis. The contents of Nan Jing are as follows: 1-23 Nan-pulse and pulse condition, 24~29 Nan-channels and collaterals, 30~47 Nan-viscera and bowels(Zang Fu organs), 48~61 Nan-disease, 62~68 Nan-acupuncture points, 69~91 Nan-acupuncture. Especially, diagnosis techniques in Nan Jing make 'Only method of cunkou pulse taking' that is a technique for feeling the pulse widely applied in these days in Oriental medicine clear. Thus, this book adjusts the theory of pulse and pulse condition given in 1~23 Nan of 'The Study of Nan Jing' in order to enhance an understanding about the theory of pulse and pulse condition. The text of 1~23 Nan about pulse lore centers on all pulse of human body interconnected each other and cunkou, both ends of the pulse, and contrasts regular pulse with irregular pulse. 1. 10 Nan describes the theory about five kinds of evils and hardness and softness, and unique pulse condition of each bowels. 2. 13 Nan explains that the relative difficulty of medical treatment is determined by the degree of balance or unbalance among three factors-colors, pulse and pulse condition, flesh shape. 3. 14 Nan divides pulse and pulse condition into slow pulse and rapid pulse, and explains separately abnormality, great loss of semen, death caused by slow pulse, and abnormality, great loss of semen, death caused by rapid pulse. 4. 15 Nan about taut pulse(弦), full pulse(鉤), floating pulse(毛), deep pulse(石脈) describes that pulse and pulse condition differs according to four seasons. Therefore, Nan Jing establishes clearly techniques of feeling the pulse in 'Only method of cunkou pulse taking(獨取寸口)' and advances the theory of Nei Jing. Futhermore, Nan Jing is more valuable in that it suggests unique theory different with Nei Jing.

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Analysis of Quorum Sensing-Related Phenotypes of Pseudomonas aeruginosa Clinical Isolates (녹농균 임상균주의 쿼럼 센싱 관련 표현형 분석)

  • Jung, Kyung-Ju;Choi, Yu-Sang;Ha, Chang-Wan;Shin, Jeong-Hwan;Lee, Joon-Hee
    • Korean Journal of Microbiology
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    • v.46 no.3
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    • pp.240-247
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    • 2010
  • Pseudomonas aeruginosa is a Gram (-) opportunistic human pathogen causing a wide variety of infections on lung, urinary tract, eyes, and burn wound sites and quorum sensing (QS), a cell density-sensing mechanism plays an essential role in Pseudomonas pathogenesis. In order to investigate the importance of QS in the Pseudomonas infections of Korean patients, we isolated 189 clinical strains of P. aeruginosa from the patients in Pusan Paik Hospital, Busan, South Korea. The QS signal production of these clinical isolates was measured by signal diffusion assay on solid media using reporter strains. While most clinical strains (79.4%) produced the QS signals as similar level as a wild type strain, PAO1 did, where LasR, the initial QS signal sensor-regulator was fully activated, a minority of them (4.2%) produced much less QS signals at the level to which LasR failed to respond. Similarly, while 72.5% of the clinical isolates produced QS signals enough to activate QscR, an another QS signal sensor-regulator, some few of them (9%) produced the QS signals at much lower level where QscR was not activated. For further analysis, we selected 74 clinical strains that were obtained from the patients under suspicion of Pseudomonas infection and investigated the total protease activity that is considered important for virulence. Interestingly, significant portion of them showed very low protease activity (44.6%) or no detectable protease activity (12.2%). When the biofilm-forming ability that is considered very important in chronic infection was examined, most isolates showed lower biofilm-forming activity than PAO1. Similarly, significant portion of clinical isolates showed reduced motility (reduced swarming activity in 51.4% and reduced twitching activity in 41.9%), or non-detectable motility (swarming-negative in 28.4% and twitching-negative in 28.4%). Our result showed that the clinical isolates that produced QS signals at the similar level to wild type could have significantly reduced activities in the protease production, biofilm formation, and motility, and some clinical isolates had unique patterns of motility, biofilm formation, and protease production that are not correlated to their QS activity.

A Study on the Reproduction Experimental of Breaking of dried stalks technique of Recorded in Oju-Yeonmunjang jeon-Sango in the late Joseon Dynasty (조선 후기 『오주연문장전산고』에 기록된 자연건조쇄경식 제섬 기술 재현 실험 연구)

  • Kong, Sanghui;Ree, Jiwon;Kim, Hajin
    • Korean Journal of Heritage: History & Science
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    • v.52 no.4
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    • pp.170-183
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    • 2019
  • Fiber scutching refers to the process of extracting fibers from plants by separating or extracting fibers from the raw materials. As the definition of the term implies, the "Fiber Scutching" is performed on plants with advanced bast fiber as the primary material processing technique performed on plant materials. Some of the most popular phosphorus plants are ramie, hemp, flax, and the paper mulberry, which have a long history of cultivation and a wide range of distribution, making them very universal as a material supporting human life and culture. This study was described in Oju-yeonmunjangjeon-sango but was designed to re-examine the method of breaking dried stalks, which is currently unused in Korea, to examine the feasibility and characteristics of the technology. As a result of sampling and experimenting with hemp bast using the method recorded in the literature, hemp fiber was actually produced. The criteria for removing the shell from the hemp stem were the degree of discoloration and drying, and only when the stalk was completely discolored to yellow could segregation of the stalk from the shell be performed. The amount of sunlight and temperature were conditions that accelerated drying. However, if exposed for a long time, it is confirmed that hemp bast will be in a suitable condition to process, regardless of the amount of sunlight and temperature. 'Breaking of dried stalks', which utilizes the physical power of 'threshing with a flail' is considered a core process of the fiber scutching technique in 'Yukjin' in Hamgyeong-do. The bark and the core of the hemp were separated by tapping, the bast was thinly split, and the shell was peeled off, making it suitable for collecting with thread. The method of collecting the fibers by applying physical power causes downing on the fibers, which is to be generally avoided in the manufacture of bast fabric woven hemp or ramie. However, Hamgyeong-do's fiber scutching method seems to have applied this principle to the method of making fragile fabrics by using it in reverse. This method is distinct from the steaming or boiling of the stalks' in Andong, Korea, and it is similar to the Western method of spinning fabrics.

A Study on Anti-Bone Resorption & Osteoporosis by Taeyoungion-Jahage Extracts

  • Bae, Hyo-Sang;Cho, Hyung-Lae;Kim, Dong-Il;Lee, Tae-Kyun;Kim, Jun-Ki;Shin, Jung-Sik
    • The Journal of Korean Obstetrics and Gynecology
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    • v.15 no.4
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    • pp.61-75
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    • 2002
  • Recombinant human $interleukin-1{\beta}$ $(rhIL-1{\beta})$ regulates several activities of the osteoblast cells derived from mouse calvarial bone explants in vitro. $rhIL-1{\beta}$ stimulated cellular proliferation and the synthesis of prostaglandin $E_2(PGE_2)$ and plasminogen activator activity in the cultured cells in a dose-dependent manner. However, the induction of osteocalcin synthesis and alkaine phosphatase activity in response to vitamine D, two characteristics of the osteoblast phenotype, were antagonized by $rhIL-1{\beta}$ over a similar dose range. This study supports the role of $IL-1{\beta}$ in the pathological modulation of bone cell metabolism, with regard to implication in the pathogenesis of osteoporosis by $IL-1{\beta}$. When the mouse calvarial bone cells were used, the bone resorption induced by $IL-1{\beta}$ was strongly inhibited by calcitonin treatment, indicating osteoclast-mediated bone resorption. On the other hand, the medicinal extracts of Taeyoungjon-Jahage (T.Y.J-J.H.G extracts) was tested for whether they could inhibit $IL-1{\beta}-induced$ $PGE_2$ production. Cell viability was not significantly affected by treatment with the indicated concentration of the extracts. The T.Y.J.-J.H.G. extracts were shown to have the inhibitory effects against the synthesis of $PGE_2$. We also examined the effect of the pretreatment with a various concentrations of the T.Y.J.-J.H.G. extracts then treated the $PGE_2-induction$ agents. Pretreatment of the T.Y.J.-J.H.G. extracts for 1 h, which by itself had little effect on cell survival, did not enhance the synthesis of $PGE_2$. Furthermore, the T.Y.J-J.H.G. extracts were shown to have the protective effects against plasminogen dependent fibrinolysis induced by the bone resorption agents of $IL-1{\beta}$. Pretreatment of the T.Y.J.-J.H.G. extracts for 1 h did not enhance the plasminogen dependent fibrinolysis. Finally, calcitonin showed the inhibitory activity the $IL-1{\beta}-stimulated$ bone resorption in the mouse calvarial bone cells having both of the osteoblast and osteoclast cells. Seemingly, pretreatment of the T.Y.J.-J.H.G. extracts for 1 h reduced the bone resorption. These results clearly indicated that calcitonin and T.Y.J.-J.H.G. extracts play key roles in inhibition of the osteoclast-mediated bone resorption.

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Effect of Conjugated Linoleic Acid on Nuclear Factor-${\kappa}B$ Activation and Tumor Necrosis Factor-${\alpha}$ Production in RAW 264.7 Cells Exposed to High Concentration of Glucose (고농도의 당에 노출된 RAW 264.7 세포에서 conjugated linoleic acid의 TNF-${\alpha}$ 생산과 NF-${\kappa}B$의 활성 효과)

  • Lee, Minji;Kang, Byeong-Teck;Kang, Ji-Houn;Yang, Mhan-Pyo
    • Journal of Veterinary Clinics
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    • v.29 no.5
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    • pp.361-367
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    • 2012
  • Diabetes-related complications in human and veterinary medicine have been shown to be associated with hyperglycemia-induced inflammation. It has been recently suggested that the onset of insulin resistance may be caused by over-production of inflammatory cytokines such as tumor necrosis factor (TNF)-${\alpha}$ from immune cells. Conjugated linoleic acid (CLA) regulates inflammatory response through modulation of TNF-${\alpha}$ expression. The objective of this study was to examine the effect of CLA on nuclear factor kappaB (NF-${\kappa}B$) p65 binding activity, inhibitory kappaB ($I{\kappa}B$)-${\alpha}$ expression, and TNF-${\alpha}$ production from high glucose-treated RAW 264.7 cells. CLA was added to RAW cells that had been previously cultured with low or high concentration of glucose. The levels of TNF-${\alpha}$ protein in the culture supernatant of RAW cells exposed to high concentrations of glucose were higher than those of cells exposed to low concentrations of glucose. The treatment with the high concentration of glucose in RAW cells increased levels of NF-${\kappa}B$ p65 binding activity and the decreased $I{\kappa}B-{\alpha}$ expression when compared with those of low glucose. The treatments in combination with CLA and glucose (low and high) glucose in RAW cells increased TNF-${\alpha}$ production when compared with that glucose alone. These treatments with CLA increased TNF-${\alpha}$ production in high glucose-treated RAW cells than those with low glucose. These treatments of CLA also showed higher NF-${\kappa}B$ p65 binding activity and lower $I{\kappa}B-{\alpha}$ expression in high glucose than those in low glucose condition. This suggests that CLA can increase NF-${\kappa}B$ p65 binding activity and TNF-${\alpha}$ production from high glucose-treated RAW 264.7 cells and is likely to promote hyperglycemia-induced inflammation.

Evaluation of the testicular toxicity caused by 2-bromopropane in rats (랫드에 있어서 2-bromopropane에 의해 유발된 정소독성의 평가)

  • Kim, Jong-choon;Lee, Hyun-sook;Yun, Hyo-in;Chung, Moon-koo
    • Korean Journal of Veterinary Research
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    • v.40 no.2
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    • pp.361-371
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    • 2000
  • It has been recently reported that 2-bromopropane (2-BP) induces male reproductive toxicity in both human and experimental animals. However, delayed effects of 2-BP on male reproductive system have not been investigated in detail. The present study was conducted to investigate the testicular toxicity of 2-BP and to determine the recovery of normal spermatogenesis in Sprague-Dawley rats. Male rats aged 5 weeks were administered 1,000mg/kg 2-BP by gavage daily for 4 weeks and sacrificed sequentially at 1, 2, 3, 4 and 12 weeks after initiation of 2-BP treatment. Testicular toxicity was evaluated qualitatively by histopathological examinations and quantitatively by reproductive organ weights, spermatid head count, and repopulation index. In the 2-BP treated rats, the body weights was significantly suppressed and the weights of testes and epididymides were also decreased in a time-dependent manner. On histopathological examination, spermatogonia in stages I-VI and preleptotene and leptotene spermatocytes in stages VII-IX were strongly depleted at 1 week of dosing. Spermatogonia were depleted extensively in all spermatogenic stages at 2 weeks. Continuing with the evolution of spermatogenic cycle, zygotene spermatocytes, pachytene spermatocytes, and round spermatids were sequentially depleted at 2, 3, and 4 weeks of dosing due to the depletion of their precursor cells. Vacuolization of Sertoli cells and spermatid retention were also observed at all time points, suggesting that 2-BP induced Sertoli cell dysfunction. At 12 weeks, after 8 weeks recovery, most of the tubules appeared severely atrophic and were lined by Sertoli cells only. Leydig cell hyperplasia in the interstitial tissue was also found. In addition, dramatic reductions in the number of spermatid heads and repopulation index were observed, indicating that 2-BP-induced testicular injury is irreversible. These results indicate that 4 weeks repeated-dose of 1,000mg/kg 2-BP results in a progressive germ cell loss due to the depletion of spermatogonia followed by long-term testicular atrophy in SD rats.

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