• Title/Summary/Keyword: aggregation formation

Search Result 270, Processing Time 0.028 seconds

Ginsenosides-mediated Vascular Relaxation and Its Molecular Mechanisms (진세노사이드의 혈관확장작용과 분자기전)

  • Kim, Nak-Doo
    • Journal of Ginseng Research
    • /
    • v.32 no.2
    • /
    • pp.89-98
    • /
    • 2008
  • There are increasing evidences in the literatures on the potential role of ginsenosides in treating cardiovascular diseases. In this article, current information about ginsenosides-mediated vascular relaxation are reviewed. From the published studies using isolated organs, cell culture systems and animal models, ginsenosides are shown to relax blood vessels and improve blood flow through diverse mechanisms, including nitric oxide release by activating eNOS phosphorylation via PI3K/Akt and/or ERK1/2 pathways in endothelial cells, induction of inducible nitric oxide synthase through activation of NF-${\kappa}$B, reducing the intracelluar Ca$^{2+}$ levels by activating Ca$^{2+}$-activated K$^{+}$ channels in vascular smooth muscle cells and reducing platelet aggregation by decreasing thromboxane A$_2$ formation and intracelluar Ca$^{2+}$in platelets. In addition, the relevant clinical trials regarding the effects of ginsenosides on the cardiovascular disease are summarized, particulary focusing on managing hypertension and improving thrombotic disorders. Finally, antagonistic effects of ginsenosides on the prostaglandin H$_2$ receptor and scavenging effects on the generation of oxygen-derived free radicals in spontaneously hypertensive rats (SHR) are discussed.

A Phenomenological Study on Micellization and Solubilization (Micelle 형성에 관한 현상학적 고찰)

  • Myung Soo Kim
    • Journal of the Korean Chemical Society
    • /
    • v.33 no.5
    • /
    • pp.459-467
    • /
    • 1989
  • When the sufactants are dissolved in water, they associate to form micelles and solubilize oil inside the micelle to form swollen micelles. Although spherical aggregates like micelles and swollen micelles occupy the same regions in the phase diagram of water-oil-surfactant systems, they are treated in different viewpoint for the formation of such aggregates. Hence a unified thermodynamic formalism for the formation of such structure is presented in this study. In all cases, the to ideal solution theory is applied for dilute system and the energy of formation is expressed as the sum of hydrophobic interaction energy and surface energy due to surfactant film. From the model, critical micelle concentration (CMC), average aggregation number, and solubilization ratio are predicted and compared with the known experimental observation.

  • PDF

Inhibitory effects of isoscopoletin on thrombus formation via regulation of cyclic nucleotides in collagen-induced platelets

  • Lee, Dong-Ha
    • Journal of Applied Biological Chemistry
    • /
    • v.63 no.3
    • /
    • pp.235-241
    • /
    • 2020
  • An essential component of the hemostatic process during vascular damage is platelet activation. However, many cardiovascular diseases, such as atherosclerosis, thrombosis, and myocardial infarction, can develop due to excessive platelet activation. Isoscopoletin, found primarily in plant roots of the genus Artemisia or Scopolia, has been studied to demonstrate potential pharmacological effects on Alzheimer's disease and anticancer, but its mechanisms and role in relation to thrombus formation and platelet aggregation have not yet been discovered. This research investigated the effect of isoscopoletin on collagen-induced human platelet activation. As a result, isoscopoletin strongly increased cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels in a concentration-dependent manner. In addition, isoscopoletin greatly phosphorylated inositol 1,4,5-triphosphate receptor (IP3R) and vasodilator-stimulated phosphoprotein (VASP), known substrates of cAMP-dependent kinase and cGMP dependent kinase. Phosphorylation of IP3R by isoscopoletin induced Ca2+ inhibition from the dense tubular system Ca2+ channels, and VASP phosphorylation was involved in fibrinogen binding inhibition by inactivating αIIb/β3 in the platelet membrane. Isoscopoletin finally reduced thrombin-induced fibrin clot production and finally reduced thrombus formation. Therefore, this research suggests that isoscopoletin has strong antiplatelet effects and is likely to be helpful for thrombotic diseases involving platelets by acting as a prophylactic and therapeutic agent.

The Formation of Rope- and Pebbles-Type Aggregation from the Micro-End-to-End and -Side-by-Side Aggregates in Poly(L-proline) Solutions

  • 김현돈
    • Bulletin of the Korean Chemical Society
    • /
    • v.18 no.9
    • /
    • pp.929-933
    • /
    • 1997
  • Morphological studies in the micro-end-to-end (m-E-E) and micro-side-by-side (m-S-S) aggregations were conducted by using of scanning electron microscope (SEM) for the samples precipitated by heating of the end-products of the transition of FormⅡ (left-handed helix, three peptides per turn, 31) Form Ⅰ (right-handed helix, 3.3 peptides per turn, 103) in poly(L-proline) (PLP) in acetic acid(water)-propanol (1:9 v/v) solvent. The observed morphology for the solide state shows a rope (or super helical) type and pebbles type aggregate for the (m-E-E) and (m-S-S) aggregate respectively. The viscosities were also measured during the heat-precipitation in order to elucidate the process of formation of the rope- and pebbles-type aggregates. The result for the (m-E-E) aggregations exhibit two steps, i.e., at first, the viscosity increases with time (step 1), thereafter it decrease until attain the last value (step 2). But the (m-S-S) aggregations show only one step in the decreases in viscosity. On the bases of all experimental results it is possible to propose a reasonable mechanism for the formation of the two types of aggregates of the (m-E-E) and (m-S-S).

Thymol Rich Thymbra capitata Essential Oil Inhibits Quorum Sensing, Virulence and Biofilm Formation of Beta Lactamase Producing Pseudomonas aeruginosa

  • Qaralleh, Haitham
    • Natural Product Sciences
    • /
    • v.25 no.2
    • /
    • pp.172-180
    • /
    • 2019
  • Infections with Pseudomonas aeruginosa are difficult to treat not only because it is often associated with multidrug-resistant infections but also it is able to form biofilm. The aim of this study was to evaluate the antibiofilm and anti-Quorum Sensing (QS) activities of Thymbra capitata essential oils (EOs) against Beta Lactamase (BL) producing P. aeruginosa and the reference strain P. aeruginosa 10145. GC/MS analysis showed that thymol (23.25%) is the most dominant compound in T. capitata EOs. The MICs of T. capitata EOs against P. aeruginosa (BL) and P. aeruginosa 10145 were 1.11%. At sub MIC (0.041, 0.014 and 0.0046%), the EOs of T. capitata remarkably inhibited the biofilm formation of both strains tested and complete inhibition of the biofilm formation was reported at 0.041%. The EOs of T. capitata were found to inhibit the swarming motility, aggregation ability and hydrophobic ability of P. aeruginosa (BL) and P. aeruginosa 10145. Interestingly, the EOs of T. capitata reduce the production of three secreted virulence factors that regulated by QS system including pyocyanin, rhamnolipids and LasA protease. The potent antibiofilm and anti-QS activities of T. capitata EOs can propose it as a new antibacterial agent to control pseudomonas infections.

A PHASE CONTRAST MICROSCOPIC STUDY OF THE EFFECT OF PHENOL ON UNFIXED ODONTOBLAST (PHENOL이 미고정(未固定) 조상아세포(造象牙細胞)에 미치는 영향(影響)에 관(關)한 위상차현미경적(位相差顯微鏡的) 연구(硏究))

  • Hong, Kyoung-Taik
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.17 no.1
    • /
    • pp.47-59
    • /
    • 1979
  • In order to study the morphologic changes of the unfixed odontoblasts suspended in phenol solution of several different concentrations, the author carried out the extraction of lower incisor of S-D strain rats to collect the odontoblasts, and the cells obtained were suspended immediately in saline solution. After observing the odontoblasts in fresh state, the saline solution was substituted with 0.125%, 0.25% 0.5%, 1% and 2% diluted phenol solutions. The morphologic changes were examined with phase contrast microscope at intervals of 10, 30, and 60 minutes. The results were as follows: 1. In saline solution the odontoblast showed cytoplasmic swelling, slender cytoplasmic process, thick rim nuclear membrane with increased dark contrast, and prominent nucleoli and chromatin granules with lapse of time intervals. In accordance with time intervals, blisters appeared in the supranuclear zone and increased its size and moved outward of the cytoplasmic membrane resulting detachment from the cell membrane. The phase dark cytoplasmic granules were increased in its dark contrast and in its size. 2. In 0.125% and 0.25% phenol solution, the odontoblasts and its nucleus shrunk immeidately and its contrast of cellular components was increased. With the lapse of time, the phase-dark granules in cytoplasm were aggregated, and several blisters were formed in and out of the cells. The outline of cytoplasmic membrane was also obscured. 3. In 0.5% phenol solution, the necleus shrunk at once, but soon after it revealed karyolysis accompanying dark contrast of neclear components such as nuclear membrane, nucleoli, and chromatin granules. On the contrary, the cytoplasmic granules showed aggregation and increased dark contrast, small and large blisters were formed in and out of the odontblasts and the outline of cytoplasmic membrane became obscured. 4. In 1% phenol solution, it showed shrinkage of odontblasts and its nuclei with thick rim nuclear membrane, aggregation of chromatin granules and occasional karyorrhexis. The dark contrast of cytoplasmic granules was increased and aggregated each other. But the blister formation could not be found. 5. In 2% phenol solution, it showed the shrinkage of odontoblasts and pyknotic nuclei with increased dark contrast of nucleoli and chromatin granules. The number of cytoplasmic granules was decreased by aggregation. But the blister formation could not be found as in 1% phenol solution.

  • PDF

Suppression of Autophagy and Activation of Glycogen Synthase Kinase 3beta Facilitate the Aggregate Formation of Tau

  • Kim, Song-In;Lee, Won-Ki;Kang, Sang-Soo;Lee, Sue-Young;Jeong, Myeong-Ja;Lee, Hee-Jae;Kim, Sung-Soo;Johnson, Gall V.W.;Chun, Wan-Joo
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.15 no.2
    • /
    • pp.107-114
    • /
    • 2011
  • Neurofibrillary tangle (NFT) is a characteristic hallmark of Alzheimer's disease. GSK3β has been reported to play a major role in the NFT formation of tau. Dysfunction of autophagy might facilitate the aggregate formation of tau. The present study examined the role of GSK3${\beta}$-mediated phosphorylation of tau species on their autophagic degradation. We transfected wild type tau (T4), caspase-3-cleaved tau at Asp421 (T4C3), or pseudophosphorylated tau at Ser396/Ser404 (T4-2EC) in the presence of active or enzyme-inactive GSK3${\beta}$. Trehalose and 3-methyladenine (3-MA) were used to enhance or inhibit autophagic activity, respectively. All tau species showed increased accumulation with 3-MA treatment whereas reduced with trehalose, indicating that tau undergoes autophagic degradation. However, T4C3 and T4-2EC showed abundant formation of oligomers than T4. Active GSK3${\beta}$ in the presence of 3-MA resulted in significantly increased formation of insoluble tau aggregates. These results indicate that GSK3${\beta}$-mediated phosphorylation and compromised autophagic activity significantly contribute to tau aggregation.

Study on Role of Platelet Aggregation in Cerebrovascular Disease (뇌졸중증(腦卒中症)에 있어서 혈소판(血少板) 응집( 凝集)의 역할에 관한 연구(硏究))

  • Hong, Ki-Whan;Lee, Won-Suk
    • The Korean Journal of Pharmacology
    • /
    • v.18 no.2
    • /
    • pp.15-25
    • /
    • 1982
  • It was undertake to investigate the factors involved in the micro thrombus formation in the plasma from the patients with cerebrovascular disease(CVD) and the in vitro actions of sodium nitroprusside on the platelet aggregate formation. 1) The microthrombus formation in the plasma from CVD was significantly enhanced, in comparison with that from the healthy volunteers. 2) Both lipid peroxide and cathepsin D in the plasma from CVD were higher than those levels from the healthy volunteers. 3) Whereas the platelets from healthy individuals showed less aggregation activity in response to ADP in the second phase those from CVD revealed the enhanced aggregating response to ADP. 4) When the bovine basilar artery, rabbit aorta and human umbilical artery were pretreated with $K^+-free$ PSS, ouabain, 13-hydroperoxylinoleic acid(13-HPLA) and cadmium they markedly enhanced the platelet aggregability respectively. 5) Platelet aggregation induced by $K^+-free$ PSS-treated bovine basilar artery was decreased by sodium nitroprusside in a dose-dependent manner, but not by either hydralazine. 6) Both dibutyryl cyclic AMP and 8-bromo cyclic GMP had the inhibitory action on the platelet aggregation. However, the latter had more prominent action than former. The antiaggregating effect by sodium nitroprusside was antagonized by pretreatment with methylene blue, but not by hemoglobin. These results provide the evidences for the therapeutic use of sodium nitroprusside in the emergency of cerebrovascular disease and in remains the further study of the clinical therapy with it.

  • PDF

Effect of Organic Material Treatments on Soil Aggregate Formation in Reclaimed Tidelands (유기물 처리가 간척지 토양의 입단형성에 끼치는 영향)

  • Son, Jae-Gwon;Cho, Jae-Young
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.42 no.3
    • /
    • pp.201-206
    • /
    • 2009
  • It is generally accepted that organic materials are a significant factor on the soil aggregation formation but little information exists on how the formation and stabilization of aggregates in reclaimed tidelands. In this work, the effects of organic materials on the soil aggregate formation in reclaimed tidelands were determined. The soil was treated with 5 cm-size chopped fresh italian ryegrass residues (fresh organic material), commercial livestock compost with swine manure and sawdust (by product fertilizer), and fresh organic material + by product fertilizer (1 : 1 w/w) after ploughing at 20 cm soil depth. The three organic materials applied $2,000kg\;10a^{-1}$ every year. Water stable aggregate was estimated by wet-sieving method. Three years after the beginning of the experiment, water stable aggregate rate and MWD (mean weight diameter) were higher fresh organic material treatment than two other treatments. For improvement of physical property and structure of soil in reclaimed tidelands, fresh organic material treatment was more suitable than two other treatments.

Growth and Characteristics of Monodispersed Spherical Silica Particles by Sol-Gel Method (졸-겔 법에 의한 단분산 구형 실리카 입자의 성장과 특성에 관한 연구)

  • 윤호성;박형상
    • Proceedings of the Korea Association of Crystal Growth Conference
    • /
    • 1997.10a
    • /
    • pp.13-19
    • /
    • 1997
  • From the formation of the monodispersed silica particle which is a valuable for the industry by Sol-Gel process, the effects of the parameters participated in the process, the growth mechanism and the characteristics of silica particles for each rection conditions are investigated. To investigate about the formation of final silica particles, the suspension which performs the polymerization is reacted with molybdic acid, and the evolutions of TEOS and silica particle size are investigated in the reaction time ? 새 the characteristics of molybdic acid with the suspension. From the results, a constant number of silica particle is formed at early reaction stage. Silica particles grow through the aggregation of smaller particles and nucleation is rate-limiting step for the growth of particles. In the conditions of this study, spherical silica particles are formed, [NH$_3$] and [$H_2O$] concentration increase the particle size but particle size decrease with [$H_2O$] concentration which is a certain above region. Average particle sizes are 187.4~483.3 nm and standard deviations in the average particle size are 1.7~2.9% with each experimental condition. From the BET results, specific surface area is 5.5~23.4 $m^2$/g and these values decrease with increase size. The average pore size is 50~70$\AA$.

  • PDF