• 제목/요약/키워드: $T_2$ contrast

검색결과 1,031건 처리시간 0.028초

Effects of Gonadotropin-Releasing Hormone on in vitro Gonadotropin Release in Testosterone-Treated Immature Rainbow Trout

  • Kim, Dae-Jung;Kim, Yi-Cheong;Aida, Katsumi
    • Animal cells and systems
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    • 제13권4호
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    • pp.429-437
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    • 2009
  • The control mechanism of gonadotropin-releasing hormone (GnRH) on gonadotropin (GTH) release was studied using cultured pituitary cell or cultured whole pituitary obtained from Testosterone (T) treated and control immature rainbow trout. The release of FSH was not changed by salmon type GnRH (sGnRH), chiken-II type (cGnRH-II), GnRH analogue ([des-$Gly^{10}D-Ala^6$] GnRH ethylamide) and GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) in cultured pituitary cells of T-treated and control fish. Indeed, FSH release was not also altered by sGnRH in cultured whole pituitary. All tested drugs had no effect on the release of LH in both culture systems of control fish. The levels of LH, in contrast, such as the pituitary content, basal release and responsiveness to GnRH were increased by T administration in both culture systems. In addition, the release of LH in response to sGnRH or cGnRH-II induced in a dose-dependent manner from cultured pituitary cells of T-treated fish, but which is not significantly different between in both GnRH at the concentration examined. Indeed, LH release was also increased by sGnRH in cultured whole pituitary of T-treated fish. GnRH antagonist suppressed the release of LH by sGnRH ($10^{-8}\;M$) and GnRH analogue ($10^{-8}\;M$) stimulation in a dose-dependent manner from cultured pituitary cells of T-treated fish, and which were totally inhibited by $10^{-7}\;M$ GnRH antagonist. These results indicate that the sensitivity of pituitary cells to GnRH is elevated probably through the T treatment, and that GnRH is involved in the regulation of LH release. GnRH-stimulated LH release is inhibited by GnRH antagonist in a dose-dependent manner. The effects of gonadal steroids on FSH levels are less clear.

Effect of labiolingual inclination of a maxillary central incisor and surrounding alveolar bone loss on periodontal stress: A finite element analysis

  • Choi, Sung-Hwan;Kim, Young-Hoon;Lee, Kee-Joon;Hwang, Chung-Ju
    • 대한치과교정학회지
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    • 제46권3호
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    • pp.155-162
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    • 2016
  • Objective: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force ($M_t/F$) in controlled tipping and consequent stresses on the periodontal ligament (PDL). Methods: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations ($5^{\circ}$, $10^{\circ}$, $15^{\circ}$, and $20^{\circ}$) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The $M_t/F$ necessary for controlled tipping ($M_t/F_{cont}$) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. Results: As labial inclination increased, $M_t/F_{cont}$ and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in $M_t/F_{cont}$ and the length of the moment arm. When $M_t/F$ was near $M_t/F_{cont}$, increases in Mt/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. Conclusions: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.

Interaction of Cu(II)-meso-tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4) with Native and Synthetic Polynucleotides Probed by Polarized Spectroscopy

  • Lee, Mi-Jin;Lee, Gil-Jun;Lee, Dong-Jin;Kim, Seog-K.;Kim, Jong-Moon
    • Bulletin of the Korean Chemical Society
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    • 제26권11호
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    • pp.1728-1734
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    • 2005
  • The interactions of Cu(II)-meso-Tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4), respectively referred to as o-, m- and p-CuTMPyP, and DNA, poly$[d(A-T)_2]$ and poly$[d(G-C)_2]$ were investigated by circular and linear dichroism (CD and LD). In the o-CuTMPyP case, in which the rotation of the pyridinium ring is prevented, the shape of the CD spectrum when associated to DNA and poly$[d(A-T)_2]$ resembles and is characterized by a positive band at a low drug to DNA concentration ratio (R ratio) and is bisignate at a high R ratio. The former CD spectrum shape has been attributed to porphyrin that is bound monomerically outside of DNA while the latter can be attributed to those that are stacked. When o-CuTMPyP is bound to poly$[d(G-C)_2]$, the excitonic CD appeared at a relatively high R ratio. In contrast, a characteristic negative CD band in the Soret region was apparent for both m- and p-CuTMPyP when bound to DNA and poly$[d(G-C)_2]$ at the low R ratios, indicating that the porphyrin molecule intercalates. However, the DNA is bent near the intercalation site and the plane of the porphyrin molecule tilts relative to the DNA helix axis, as judged by the magnitude of the reduced LD. Various stacking patterns were identified by the shape of the CD spectrum for m- and p-CuTMPyP when bound to poly$[d(A-T)_2]$. Three species for the former complex and two for the latter complex were found which may reflect the extent of the stacking.

보양환오탕에 의한 비특이적 세포독성 T 세포 활성 증강 (Promotion of Nonspecific Cytotoxic T Lymphocyte Activity by Bo-yang-hwan-oh-tang)

  • 하종천;김영현;우원홍;남상윤
    • 생약학회지
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    • 제32권3호통권126호
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    • pp.226-232
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    • 2001
  • To explore the possible cancer therapeutic application of "Bo-yang-hwan-oh-tang" (BH), a herbal medicinal recipe used for improvement of blood stasis, we have examined its direct cytotoxicity against tumor cell, and induction of cytotoxic activity of lymphocytes. Water extract of BH alone did not exhibit direct cytotoxicity to Yac-1 target cells even with high concentrations (10 mg/ml). By exposure for 3 days, BH did not induce any nonspecific cytotoxic activity of mouse spleen cells, either, when assessed in a 4 hr $^{51}Cr-release$ assay. However, when BH was added during CD3 stimulation of non-adherent spleen cells, non-specific CTL activity was markedly promoted in a dose dependent manner. In contrast, BH did not alter activated NK cell activity following IL-2 stimulation. These data suggest that BH does not induce but upregulates non-specific CTL effecter function and that activated NK cell does not respond to BH. For elucidation of the mechanism underlying this function of BH, time kinetic study for IL-2 production using ELISA was undertaken. IL-2 production following CD3 stimulation was significantly augmented and higher level of IL-2 is sustained over 3 days in the culture medium by BH treatment. Moreover, addition of exogenous IL-2 during CD3 stimulation resulted in a similar level of cytotoxicity between control and BH-treated culture. These data indicate that the BH-mediated upregulation of non-specific CTL activity is contributed by augmentation of IL-2 production. Our data imply the possible application of BH for combination therapy of cancer with non-specific activator.

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Measurement of Apparent Diffusion Coefficient Values from Diffusion-Weighted MRI: A Comparison of Manual and Semiautomatic Segmentation Methods

  • Kim, Seong Ho;Choi, Seung Hong;Yoon, Tae Jin;Kim, Tae Min;Lee, Se-Hoon;Park, Chul-Kee;Kim, Ji-Hoon;Sohn, Chul-Ho;Park, Sung-Hye;Kim, Il Han
    • Investigative Magnetic Resonance Imaging
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    • 제19권2호
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    • pp.88-98
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    • 2015
  • Purpose: To compare the interobserver and intraobserver reliability of mean apparent diffusion coefficient (ADC) values using contrast-enhanced (CE) T1 weighted image (WI) and T2WI as structural images between manual and semiautomatic segmentation methods. Materials and Methods: Between January 2011 and May 2013, 28 patients who underwent brain MR with diffusion weighted image (DWI) and were pathologically confirmed as having glioblastoma participated in our study. The ADC values were measured twice in manual and semiautomatic segmentation methods using CE-T1WI and T2WI as structural images to obtain interobserver and intraobserver reliability. Moreover, intraobserver reliabilities of the different segmentation methods were assessed after subgrouping of the patients based on the MR findings. Results: Interobserver and intraobserver reliabilities were high in both manual and semiautomatic segmentation methods on CE-T1WI-based evaluation, while interobserver reliability on T2WI-based evaluation was not high enough to be used in a clinical context. The intraobserver reliability was particularly lower with the T2WI-based semiautomatic segmentation method in the subgroups with involved $lobes{\leq}2$, with partially demarcated tumor borders, poorly demarcated inner margins of the necrotic portion, and with perilesional edema. Conclusion: Both the manual and semiautomatic segmentation methods on CE-T1WI-based evaluation were clinically acceptable in the measurement of mean ADC values with high interobserver and intraobserver reliabilities.

자기공명 담관췌장초영술에서 음성 경구 조영제로 사용한 초상자성 산화철 제재의 유용성 (Usefulness of Superparamagnetic Iron Oxide (SPIO) as a Negative Oral Contrast Agent in MR Cholangiopancreatography)

  • 이정민;송원규;이종덕
    • Investigative Magnetic Resonance Imaging
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    • 제5권1호
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    • pp.49-56
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    • 2001
  • 목적 자기공명 담관췌장조영술(MR Cholangiopancreatography, 이하 MRCP)에서 음성 경구 조영제로 사용한 초상자성 산화철 (Superparamagnetic iron oxide, SPIO) 제제의 유용성을 영상 질의 향상 효과를 통하여 알아보고자 하였다. 대상 및 방법: 임상소견, 이학적 검사 및 초음파 검사에서 담도와 췌장질환이 의심되었던 48명의 환자와 자원자 6명을 대상으로 하였다 음성 경구 조영제로 사용한 SPIO 제재의 적정 농도의 선택을 위해 정주용 SPIO제재 0.5ml, 0.75m1, 1 ml, 1.5 ml 및 2ml을 500m1 물에 희석시켜 가상 실험을 통하여 72강조영상에서 물의 신호강도가 완전히 소실되는 최소농도를 산출하였다. MRCP영상은 1.57를 이용하여 지방억제 HASTE (half-courier acquisition single-shot turbo spin echo) 와 터보스핀에코(Turbo spin echo) 기법을 이용하여 얻었다. 조영 후 영상은 음성 경구 조영제 300m1를 경구 섭취하고 10분 후에 얻었고, 조영 전 후 영상을 최대 신호 투영법으로 재구성하였다. 영상 분석은 조영 전 영상에 비교하여 위 십이지장내의 액체의 고신호강도에 따른 총수담판 및 췌관의 묘출의 방해 정도 및 진단의 향상 정도를 두 명의 방사선과 의사가 합의하여 정성적으로 분석하였다. 결과: 가상 실험에서, 22.4 ugFe/ml 농도의 혼합액 (Feridex I ml 용액을 자유수 500m1에 희석하여 만든 농도)에서의 신호강도 소실 백분율의 증가가 가장 현저한 변화를 보였다. 영상분석에서는, 조영 후 영상이 조영 전 영상에 비해 영상의 질이 향상되었다. 또한 환자의 25% (12/48)에서 조영 전 영상에 비하여 더 정화한 진단을 가능하게 하였다. 결론. MRCP영상 획득 시 음성 경구 조명제로서 사용된 초상자성 산화철 (SPIO) 제재는 영상질의 향상시켜 담도 및 췌장질환을 평가하는데 유용할 것으로 사료된다.

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한국산 Zeolite의 필터첨가제로서의 흡착효과에 관하여 (A Study on the Adsorption Effect of Korean zeolite "Clinoptilolite" as Cigarette Cavity Filter Additive.)

  • 양광규;송치현;김찬호
    • 한국연초학회지
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    • 제2권1호
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    • pp.8-16
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    • 1980
  • Zeolite의 일종인 clinoptilolite를 담배필터 첨가제로 활용하는 연구를 하였다. 입자크기 30 $\pm$ 5 A.S.T.M. mesh의 clinoptilolite와 charcoal 1 : 1 (V/V)로 혼합하여 삼중필터의 cavity부분에 충진했을 때, 1. Cellulose acetate필터에 비하여 nicotine 35%, T.P..M.22%를 감소시켰으며, 2. Gas phase중 n-amyl alcohol등 aliphatic compound와 furan등 cyclic compound를 cellulose acetate filter에 비하여 60$\pm$ 5%를 감소시켰다. 3. Charcoal의 removal efficiency는 40-50% clinoptilolite의 10-20%에 비하여 큰 값이였지만 charcoal은 분자량이 큰 aromatic compound의 removal efficiency가 50$\pm$5%로서 aliphatic compound의 removal efficiency 40: 5%보다 큰 값이였음에 비하여 clinoptilolite는 alcohol과 ketone계열의 분자갹이 작은 화합물의 removal efficiency가 15-20%로 cyclic compounds의 removal efficiency 10-15%에 비하여 보다 큰 값이었다. 이 두물질의 gas phase성분의 흡착기능은 상호 보완적임을 알 수 있었다.

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Predicting lipoabdominoplasty complications with infrared thermography: a delta-R analysis

  • Resende, Patricia Rodrigues;Brioschi, Marcos Leal;Meneck, Franciele De;Neves, Eduardo Borba;Teixeira, Manoel Jacobsen
    • Archives of Plastic Surgery
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    • 제48권5호
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    • pp.553-558
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    • 2021
  • The diagnosis of the main complications resulting from lipoabdominoplasty has not yet been standardized. Infrared thermal imaging has been used to assess possible complications, such as necrosis and changes in micro- and macro-circulation, based on perforator mapping techniques, among others. The objective of this study was to present two clinical cases involving thermal imaging monitoring of the healing process of lipoabdominoplasty in the immediate postoperative evaluation and its preliminary results. Infrared thermography was performed 24 hours after the operation and on postoperative days 5, 25, and 27. In clinical case 1, it was found that the delta-R (∆TR)-defined as the difference in minimum temperature between the highest and lowest points in the SA3 region (caution suction area) following the classification established by Matarasso-was 0.4℃ at 24 hours after surgery and decreased to 0.1℃ on a postoperative day 5. There were no complications in this case. In contrast, in clinical case 2, the ∆TR was 1.7℃ at 24 hours after surgery (upon hospital discharge) and remained high, at 2.2℃, on postoperative day 5. A higher ∆TR was found in the second patient, who developed necrosis of the surgical wound. The ∆TR thermal index may be a new tool for predicting possible complications, complementing the clinical evaluation and therapeutic decision-making.

Fibroscan과 비교를 통한 T1 MR Relaxometry를 이용한 간섬유화의 정량적 평가 (Quantitative Evaluation of Liver Fibrosis on T1 Relaxometry in Comparison with Fibroscan)

  • 심병학;허숙희;신상수;조성범;정용연
    • 대한영상의학회지
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    • 제81권2호
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    • pp.365-378
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    • 2020
  • 목적 본 연구는 gadoxetic acid 조영증강 간 자기공명영상에서 T1 이완시간이 만성간질환을 가진 환자에서 간섬유화의 발견과 병기설정에 유용한지 알아보고자 한다. 대상과 방법 국소간병변이 의심되는 103명 환자들이 간 자기공명영상과 Fibroscan을 시행하였다. Fibroscan은 간섬유화의 정도를 분류하는 참조표준검사로 사용되었다. T1 이완시간은 조영제 주입 전(preT1)과 주입 20분 후(postT1), 그리고 이들 간의 T1 이완시간 감소율(rrT1)을 3 테슬라 자기공명영상의 횡단 3D VIBE 시퀀스 하에 측정하였다. Receiver operating characteristic (이하 ROC) 분석을 통해 간섬유화 병기설정을 위한 최적의 cut-off 값이 결정되었다. 결과 METAVIR score (F0-F4)에 따른 간섬유화 병기가 증가함에 따라, preT1과 postT1은 증가하였고, rrT1은 감소하였다. PreT1의 F2와 F3 사이(F2, 836.0 ± 74.7 ms; F3, 888.6 ± 77.5 ms, p < 0.05), postT1의 F3와 F4 사이(F3, 309.0 ± 80.2 ms; F4, 406.6 ± 147.7 ms, p < 0.05), 그리고 rrT1의 F3와 F4사이(F3, 65.4 ± 7.7%; F4 57.3 ± 11.4%, p < 0.05)에서 통계적 유의미한 차이를 보였다. ROC 분석은 preT1과 postT1의 병용검사가 간섬유화 병기설정에 있어 가장 유용한 검사라는 것을 보여준다. 결론 preT1과 postT1은 간섬유화 병기가 증가함에 따라 증가하며, T1 mapping이 gadoxetic acid 조영증강 간 자기공명영상에서 간섬유화 병기설정에 있어 유용한 보조적 시퀀스로 사용될 수 있다.

Cross-interaction Constants in the Nucleophilic Reactions of Carbonyl Compounds Involving a Tetrahedral Intermediate

  • Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • 제15권11호
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    • pp.985-990
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    • 1994
  • Cross-interaction constants, ${\rho}^e_{XY}$, ${\rho}_{YZ}$ and ${\rho}_{XZ}$ are defined using observed rate constant, k_N=(k_1/k_{-1})k_2=Kk_2$, for the stepwise carbonyl addition reactions involving the rate-limiting breakdown of a tetrahedral intermediate $(T^{\pm})$. Abundant experimental evidence in the literature enables us to determine signs for the three constants for such mechanism, ${\rho}^e_{XY}$>0, ${\rho}_{YZ}$<0 and ${\rho}_{XZ}$0. These are in contrast to those for the concerted $S_N2$ mechanism, ${\rho}_{XY}$<0, ${\rho}_{YZ}$>0 and ${\rho}_{XZ}$, and provide useful mechanistic criteria. In the light of these criteria, mechanisms of some nucleophilic reactions of carbonyl compounds are re-examined.