• 제목/요약/키워드: Mechanistic studies

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Functional Neuroimaging of General Fluid Intelligencein Prodigies

  • Lee, Kun-Ho
    • 한국영재학회:학술대회논문집
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    • 한국영재학회 2003년도 춘계학술대회
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    • pp.137-138
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    • 2003
  • Understanding how and why people differ is a fundamental, if distant, goal of research efforts to bridge psychological and biological levels of analysis. General fluid intelligence (gF) is a major dimension of individual differences and refers to reasoning and novel problemsolving ability. A conceptual integration of evidence from cognitive (behavioral) and anatomical studies suggeststhat gF should covary with both task performance and neural activity in specific brain systems when specific cognitive demands are present, with the neural activity mediating the relation between gF and performance. Direct investigation of this possibility will be a critical step toward a mechanistic model of human intelligence. In turn, a mechanistic model might suggest ways to enhance gF through targeted behavioral or neurobiological intervent ions, We formed two different groups as subjects based on their scholarly attainments. Each group consists of 20 volunteers(aged 16-17 years, right-handed males) from the National Gifted School and a local high school respectively. To test whether individual differences in general intelligence are mediated at a neural level, we first assessed intellectual characteristics in 40 subjects using standard intelligence tests (Raven's Advanced Progressive Matrices, Wechsler Adult Intelligence Scale, Torrance Tests of Creative Thinking) administered outside of the MR scanner. We then used functional magnetic resonance imaging (fMRl) to measure task-related brain activity as participants performed three different kinds of computerized reasoning tasks that were intended to activate the relevant neural systems. To examine the difference of neural activity according to discrepancy in general intelligence, we compared the brain activity of both extreme groups (each, n=10) of the participants based on the standard intelligence test scores. In contrast to the common expectation, there was no significant difference of brain region involved in high-g tasks between both groups. Random effect analysis exhibited that lateral prefrontal, anterior cingulate and parietal cortex are associated with gF. Despite very different task contents in the three high-g-low-g contrasts, recruitment of multiple regions is markedly similar in each case, However, on the task with high 9F correlations, the Prodigy group, (intelligence rank: >99%) showed higher task-related neural activity in several brain regions. These results suggest that the relationship between gF and brain activity should be stronger under high-g conditions than low-g conditions.

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통증과 우울증의 병합 동물모델에 대한 최신 연구 동향 분석 (A Review on the Pain and Depression Comorbidity Animal Models)

  • 송지혜;국혜정;박병진;김송이;박지연
    • Korean Journal of Acupuncture
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    • 제38권2호
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    • pp.75-99
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    • 2021
  • Objectives : The purpose of this study is to analyze animal behavioral changes and related neurobiological mechanisms in recent studies using animal models with pain and depression. Methods : We conducted database search in Pubmed, NDSL, and EMBASE up to January 2021. Included studies were classified as depression-like behavior observed in pain model, pain-like behavior observed in depression model, and pain and depression comorbidity model. The results of pain- and depression-like behaviors, the changes of neurobiological mechanisms, and the treatment methods such as drugs, natural substance-derived chemicals, or acupuncture were analyzed. Results : We included 124 studies (81 studies in depression-like behavior observed in pain model, 19 studies in pain-like behavior observed in depression model, and 24 studies in pain and depression comorbidity model). Pain and depression comorbidity animal models were induced using various methods by drugs or surgery. Von frey test, a method for evaluating mechanical allodynia was the most commonly used for measuring pain-like behavior and the forced swimming test was the most commonly used for measuring depression-likes behavior. The changes of neurobiological factors, such as decrease of 5-hydroxytryptamine and increase of oxidative stress and pro-inflammation cytokines were generally changed in the frontal cortex, hippocampus, thalamus, and spinal cord in all types of models. For treating pain and depression-like behaviors, various types of drugs such as antidepressant, tranquilizer, analgesic, and natural substance-derived chemicals were used. Acupuncture treatment was used in 4 studies. Conclusions : In the future, more diverse studies on the combined model of pain and depression need to be conducted. In addition, it is necessary to establish a mechanistic basis for the development of various treatments by identifying the common mechanisms of pain and depression.

소다아미드를 포함하는 복합염기에 의한 탈할로겐화수소반응 (제1보). 트란스-1,2-디할로시클로헥산의 탈할로겐화수소 반응의 메카니즘 연구 (Dehydrohalogenation Reactions Induced by Sodamide Containing Complex Bases (I). Mechanistic Studies on Dehydrohalogenation from trans-1,2-Dihalocyclohexanes)

  • 이종건;강경태;이억석
    • 대한화학회지
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    • 제28권1호
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    • pp.20-25
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    • 1984
  • 소다아미드를 포함하는 복합염기에 의한 트란스-1,2-디할로시클로헥산으로부터의 탈할로겐화 수소반응을 연구 검토한 결과 이성질화, 중수소 동위원소 효과 및 이탈기의 원소효과 등이 모두 E2반응 메카니즘으로 반응이 진행됨을 강력히 시사하고 있다.

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A Mitochondrial Perspective of Chronic Obstructive Pulmonary Disease Pathogenesis

  • Kang, Min-Jong;Shadel, Gerald S.
    • Tuberculosis and Respiratory Diseases
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    • 제79권4호
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    • pp.207-213
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    • 2016
  • Chronic obstructive pulmonary disease (COPD) encompasses several clinical syndromes, most notably emphysema and chronic bronchitis. Most of the current treatments fail to attenuate severity and progression of the disease, thereby requiring better mechanistic understandings of pathogenesis to develop disease-modifying therapeutics. A number of theories on COPD pathogenesis have been promulgated wherein an increase in protease burden from chronic inflammation, exaggerated production of reactive oxygen species and the resulting oxidant injury, or superfluous cell death responses caused by enhanced cellular injury/damage were proposed as the culprit. These hypotheses are not mutually exclusive and together likely represent the multifaceted biological processes involved in COPD pathogenesis. Recent studies demonstrate that mitochondria are involved in innate immune signaling that plays important roles in cigarette smoke-induced inflammasome activation, pulmonary inflammation and tissue remodeling responses. These responses are reviewed herein and synthesized into a view of COPD pathogenesis whereby mitochondria play a central role.

랫트의 신장 근위곡세뇨관 현탁액을 이용한 Cephaloridine의 신장독성 평가 (Nephrotoxicity Assessment of Cephaloridine using Rat Renal Proximal Tubule Suspension)

  • 홍충만;장동덕;신동환;최진영;조재천;이문한
    • Toxicological Research
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    • 제11권1호
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    • pp.103-108
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    • 1995
  • Rat renal proximal tubule suspension was prepared from adult male Sprague Dawley rat (250-300g) by mechanical (non-enzymatical) method and evaluated as a pontential model for mechanistic studies and early screening of nephrotoxicity, using anionic antibiotics (cephaloridine). Cephaloridine (CPL) produced an increase in LDH release into media. This release results from decrease a proximal tubule cell viability and subsequently increase the permeability of cell viability and subsequently increase the permeability of cell membrane. Since loss of intracellular potassium and ATP into media is the sign of disruption of cell membrane, especially basolateral membrane (BLM), CPL induced proximal tubule cell compromise also appear be associated with BLM, maybe $Na^+-K^+$ ATPase. Also seen was significant depression in brush border membrane (BBM) ALP activity and no significantly increase in BBM GGT activities. The inhibition of typical anion, PAH accumulation (especially, CPL 5 mM) and cation, TEA (especially, 4hours incubation) were seen dose dependently. This is because of CPL accumulation in renal proximal tubule and increase of cytotoxicity.

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4차 아민이 치환된 아닐린의 고리화반응 메카니즘 및 Pyrrolo[1,2-a]benzimidazoquinone 유도체의 합성에의 응용 (Mechanistic Studies for the Cyclization of t-Amine Substituted Anilines and Their Utilization to the Synthesis of Pyrrolo[1,2-a]benzimidazoquinone Derivatives)

  • 이창희;백호진;김국진;조규욱;오경택
    • 대한화학회지
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    • 제39권5호
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    • pp.408-413
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    • 1995
  • A few t-amine substituted anilines and amides were synthesized and cyclized to pyrrolo[1,2-a]benzimidazole by heating in various solvents having different polarity. Subsequent nitration of cyclized compound followed by reduction and oxidation of resulting amine afforded quinone such as 7 in 14% yield. The formation of imidazole moiety by thermal cyclization was independent on the solvent polarity. The regiochemistry for the nitration of 4 was unambiguously determined by chemical transformation.

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Kinetics and Mechanism of Pyridinolysis of Aryl Dithiocyclopentanecarboxylates in Acetonitrile

  • Oh, Hyuck-Keun
    • Bulletin of the Korean Chemical Society
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    • 제31권8호
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    • pp.2357-2360
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    • 2010
  • Kinetic studies on the pyridinolysis of aryl dithiocyclopentanecarboxyaltes 2 were carried out at $60.0^{\circ}C$ in acetonitrile. In the aminolysis of 2, the $\beta_X$ values were 0.5 - 0.8 with anilines, and there was no breakpoint. However, in the pyridinolysis of 2, biphasic Bronsted plots were obtained, with a change in slope from a large value ($\beta_X{\cong}0.7$) to a small value ($\beta_X{\cong}0.4$) at $pK_{a}^0$ = 5.2. This was attributed to a change in the rate-limiting step from breakdown to the formation of a zwitterionic tetrahedral intermediate, $T^{\pm}$, in the reaction path, with an increase in the basicity of the pyridine nucleophile. An obvious change in the cross-interaction constant ${\rho}_{XZ}$ from a large positive ($\rho_{XZ}$ = +1.02) value to a small negative value (${\rho}_{XZ}$ = -0.17) supports the proposed mechanistic change.

Nuclear Bodies Built on Architectural Long Noncoding RNAs: Unifying Principles of Their Construction and Function

  • Chujo, Takeshi;Hirose, Tetsuro
    • Molecules and Cells
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    • 제40권12호
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    • pp.889-896
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    • 2017
  • Nuclear bodies are subnuclear, spheroidal, and membraneless compartments that concentrate specific proteins and/or RNAs. They serve as sites of biogenesis, storage, and sequestration of specific RNAs, proteins, or ribonucleoprotein complexes. Recent studies reveal that a subset of nuclear bodies in various eukaryotic organisms is constructed using architectural long noncoding RNAs (arcRNAs). Here, we describe the unifying mechanistic principles of the construction and function of these bodies, especially focusing on liquid-liquid phase separation induced by architectural molecules that form multiple weakly adhesive interactions. We also discuss three possible advantages of using arcRNAs rather than architectural proteins to build the bodies: position-specificity, rapidity, and economy in sequestering nucleic acid-binding proteins. Moreover, we introduce two recently devised methods to discover novel arcRNA-constructed bodies; one that focuses on the RNase-sensitivity of these bodies, and another that focuses on "semi-extractability" of arcRNAs.

CRISPR and Target-Specific DNA Endonucleases for Efficient DNA Knock-in in Eukaryotic Genomes

  • Lee, Seung Hwan;Kim, Sunghyun;Hur, Junho K
    • Molecules and Cells
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    • 제41권11호
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    • pp.943-952
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    • 2018
  • The discovery and mechanistic understanding of target-specific genome engineering technologies has led to extremely effective and specific genome editing in higher organisms. Target-specific genetic modification technology is expected to have a leading position in future gene therapy development, and has a ripple effect on various basic and applied studies. However, several problems remain and hinder efficient and specific editing of target genomic loci. The issues are particularly critical in precise targeted insertion of external DNA sequences into genomes. Here, we discuss some recent efforts to overcome such problems and present a perspective of future genome editing technologies.

Kinetics and Mechanism of the Pyridinolysis of Aryl Cyclobutanecarboxylates in Acetonitrile

  • koh, Han-Joong;Han, Kwang-Lae;Lee, Hai-Whang;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • 제23권5호
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    • pp.715-720
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    • 2002
  • Kinetic studies of the reaction of Z-aryl cyclobutanecarboxylates with X-pyridines in acetonitrile at $55.0^{\circ}C$ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterion ic tetrahedral intermediate, T $\pm$ . These mechanistic conclusions are drawn based on (i) the large magnitude of ${\rho}X$ and $\rhoZ$, (ⅱ) the positive sign of ${\rho}XZ$ and the larger magnitude of $\rhoXZ$ than normal SN2 processes, (ⅲ) a small positive enthalpy of activation, ${\Delta}H{\neq}$, and a large negative, ${\Delta}S{\neq}$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.