• 제목/요약/키워드: Thermal mechanism

검색결과 1,228건 처리시간 0.028초

Synergistic interaction between acetaminophen and L-carnosine improved neuropathic pain via NF-κB pathway and antioxidant properties in chronic constriction injury model

  • Owoyele, Bamidele Victor;Bakare, Ahmed Olalekan;Olaseinde, Olutayo Folajimi;Ochu, Mohammed Jelil;Yusuff, Akorede Munirdeen;Ekebafe, Favour;Fogabi, Oluwadamilare Lanre;Roi, Treister
    • The Korean Journal of Pain
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    • 제35권3호
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    • pp.271-279
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    • 2022
  • Background: Inflammation is known to underlie the pathogenesis in neuropathic pain. This study investigated the anti-inflammatory and neuroprotective mechanisms involved in antinociceptive effects of co-administration of acetaminophen and L-carnosine in chronic constriction injury (CCI)-induced peripheral neuropathy in male Wistar rats. Methods: Fifty-six male Wistar rats were randomly divided into seven experimental groups (n = 8) treated with normal saline/acetaminophen/acetaminophen + L-carnosine. CCI was used to induce neuropathic pain in rats. Hyperalgesia and allodynia were assessed using hotplate and von Frey tests, respectively. Investigation of spinal proinflammatory cytokines and antioxidant system were carried out after twenty-one days of treatment. Results: The results showed that the co-administration of acetaminophen and L-carnosine significantly (P < 0.001) increased the paw withdrawal threshold to thermal and mechanical stimuli in ligated rats compared to the ligated naïve group. There was a significant (P < 0.001) decrease in the levels of nuclear factor kappa light chain enhancer B cell inhibitor, calcium ion, interleukin-1-beta, and tumour necrotic factor-alpha in the spinal cord of the group coadministered with acetaminophen and L-carnosine compared to the ligated control group. Co-administration with acetaminophen and L-carnosine increased the antioxidant enzymatic activities and reduced the lipid peroxidation in the spinal cord. Conclusions: Co-administration of acetaminophen and L-carnosine has anti-inflammatory effects as a mechanism that mediate its antinociceptive effects in CCI-induced peripheral neuropathy in Wistar rat.

Ginsenoside compound K reduces ischemia/reperfusion-induced neuronal apoptosis by inhibiting PTP1B-mediated IRS1 tyrosine dephosphorylation

  • Jing, Fu;Liang, Yu;Qian, Yu;Nengwei, Yu;Fei, Xu;Suping, Li
    • Journal of Ginseng Research
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    • 제47권2호
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    • pp.274-282
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    • 2023
  • Background: Ginsenoside compound K (CK) stimulated activation of the PI3K-Akt signaling is one of the major mechanisms in promoting cell survival after stroke. However, the underlying mediators remain poorly understood. This study aimed to explore the docking protein of ginsenoside CK mediating the neuroprotective effects. Materials and methods: Molecular docking, surface plasmon resonance, and cellular thermal shift assay were performed to explore ginsenoside CK interacting proteins. Neuroscreen-1 cells and middle cerebral artery occlusion (MCAO) model in rats were utilized as in-vitro and in-vivo models. Results: Ginsenoside CK interacted with recombinant human PTP1B protein and impaired its tyrosine phosphatase activity. Pathway and process enrichment analysis confirmed the involvement of PTP1B and its interacting proteins in PI3K-Akt signaling pathway. PTP1B overexpression reduced the tyrosine phosphorylation of insulin receptor substrate 1 (IRS1) after oxygen-glucose deprivation/reoxygenation (OGD/R) in neuroscreen-1 cells. These regulations were confirmed in the ipsilateral ischemic hemisphere of the rat brains after MCAO/R. Ginsenoside CK treatment reversed these alterations and attenuated neuronal apoptosis. Conclusion: Ginsenoside CK binds to PTP1B with a high affinity and inhibits PTP1B-mediated IRS1 tyrosine dephosphorylation. This novel mechanism helps explain the role of ginsenoside CK in activating the neuronal protective PI3K-Akt signaling pathway after ischemia-reperfusion injury.

Involvement of the spinal γ-aminobutyric acid receptor in the analgesic effects of intrathecally injected hypertonic saline in spinal nerve-ligated rats

  • Myong-Hwan Karm;Hyun-Jung Kwon;Euiyong Shin;Honggyoon Bae;Young Ki Kim;Seong-Soo Choi
    • The Korean Journal of Pain
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    • 제36권4호
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    • pp.441-449
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    • 2023
  • Background: Hypertonic saline is used for treating chronic pain; however, clinical studies that aid in optimizing therapeutic protocols are lacking. We aimed to determine the concentration of intrathecally injected hypertonic saline at which the effect reaches its peak as well as the underlying γ-aminobutyric acid (GABA) receptor-related antinociceptive mechanism. Methods: Spinal nerve ligation (SNL; left L5 and L6) was performed to induce neuropathic pain in rats weighing 250-300 g. Experiment 1: one week after implanting the intrathecal catheter, 60 rats were assigned randomly to intrathecal injection with 0.45%, 0.9%, 2.5%, 5%, 10%, and 20% NaCl, followed by behavioral testing at baseline and after 30 minutes, 2 hours, 1 day, and 1 week to determine the minimal concentration which produced maximal analgesia. Experiment 2: after determining the optimal intrathecal hypertonic saline concentration, 60 rats were randomly divided into four groups: Sham, hypertonic saline without pretreatment, and hypertonic saline after pretreatment with one of two GABA receptor antagonists (GABAA [bicuculline], or GABAB [phaclofen]). Behavioral tests were performed at weeks 1 and 3 following each treatment. Results: Hypertonic saline at concentrations greater than 5% alleviated SNL-induced mechanical allodynia and had a significant therapeutic effect, while showing a partial time- and dose-dependent antinociceptive effect on thermal and cold hyperalgesia. However, pretreatment with GABA receptor antagonists inhibited the antinociceptive effect of 5% NaCl. Conclusions: This study indicates that the optimal concentration of hypertonic saline for controlling mechanical allodynia in neuropathic pain is 5%, and that its analgesic effect is related to GABAA and GABAB receptors.

Anti-inflammatory and Anti-nociceptive Effects of Ethyl Acetate Fraction of Lindera glauca (감태나무 에틸아세테이트 분획의 항염증 및 진통 효과)

  • Kim, Jong Soo;Kang, Bo Hye;Park, Seung Ju;Yang, Woo In;Kim, Myung Soo;Lee, Byung Soo;Cha, Dong Seok;Lee, Se Youn;Kwon, Jin;Jeon, Hoon
    • Korean Journal of Pharmacognosy
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    • 제53권1호
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    • pp.49-56
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    • 2022
  • The present study was designed to evaluate the anti-inflammatory and anti-nociceptive potential of the ethyl acetate fraction of Lindera glauca (ELG). We found that ELG significantly suppressed NO production through decreased enzyme activity and expression of iNOS in the IFN-γ/LPS-activated murine peritoneal macrophages. The treatment of ELG also down-regulated the expression of COX-2. Our western blot data revealed that inhibitory effects of ELG on these pro-inflammatory mediators were attributed to inactivation of NF-κB. In addition, ELG-fed mice showed a marked decrease in paw edema induced by subplantar injection of trypsin, suggesting in vivo anti-inflammatory potential of ELG. We further investigated the anti-nociceptive properties of ELG using thermal and chemical nociception model. We found that ELG has a strong anti-nociceptive activities in both central and peripheral mechanism. An additional combination test with naloxone revealed that opioid receptor was not involved in the ELG-mediated anti-nociception. In conclusion, ELG may possibly be used as valuable anti-inflammatory and anti-nociceptive agent for the treatment of inflammatory diseases and pains.

Tracing history of the episodic accretion process in protostars

  • Kim, Jaeyeong;Lee, Jeong-Eun;Kim, Chul-Hwan;Hsieh, Tien-Hao;Yang, Yao-Lun;Murillo, Nadia;Aikawa, Yuri;Jeong, Woong-Seob
    • The Bulletin of The Korean Astronomical Society
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    • 제46권2호
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    • pp.66.3-67
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    • 2021
  • Low-mass stars form by the gravitational collapse of dense molecular cores. Observations and theories of low-mass protostars both suggest that accretion bursts happen in timescales of ~100 years with high accretion rates, so called episodic accretion. One mechanism that triggers accretion bursts is infalling fragments from the outer disk. Such fragmentation happens when the disk is massive enough, preferentially activated during the embedded phase of star formation (Class 0 and I). Most observations and models focus on the gas structure of the protostars undergoing episodic accretion. However, the dust and ice composition are poorly understood, but crucial to the chemical evolution through thermal and energetic processing via accretion burst. During the burst phase, the surrounding material is heated up, and the chemical compositions of gas and ice in the disk and envelope are altered by sublimation of icy molecules from grain surfaces. Such alterations leave imprints in the ice composition even when the temperature returns to the pre-burst level. Thus, chemical compositions of gas and ice retain the history of past bursts. Infrared spectral observations of the Spitzer and AKARI revealed a signature caused by substantial heating, toward many embedded protostars at the quiescent phase. We present the AKARI IRC 2.5-5.0 ㎛ spectra for embedded protostars to trace down the characteristics of accretion burst across the evolutionary stages. The ice compositions obtained from the absorption features therein are used as a clock to measure the timescale after the burst event, comparing the analyses of the gas component that traced the burst frequency using the different refreeze-out timescales. We discuss ice abundances, whose chemical change has been carved in the icy mantle, during the different timescales after the burst ends.

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Analysis of Shear Behavior of Reinforced ALWAC Beam Using Interface Elements (계면요소를 이용한 경량철근콘크리트 보의 전단거동해석)

  • Rhee, Inkyu;Kim, Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제26권1A호
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    • pp.107-115
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    • 2006
  • A challenging topic was and still is the failure behavior of concrete beams without shear reinforcement. In spite of substantial experimental and theoretical efforts in the past, the mechanism of shear failure is not entirely understood. ALWAC is of importance to the current construction industry. Most of present concrete research focuses on high performance concrete, by which in meant a cost effective material that satisfies demanding performance requirements, including durability. The advantages of ALWAC are its reduced mass and improved thermal and acoustic insulation properties, while maintaining adequate strength. In spite of these advantages, its ultimate failure behavior has not been well defined for adequate design process. This paper will investigate mainly the shear behavior of reinforced ALWAC beam without web reinforcements numerically with experimental evidences.

The synthesis and formation mechanism of the fine $BaTiO_3$ powders by ultrasonic spray pyrolysis (초음파 분무 열분해법에 의한 $BaTiO_3$ 미분말의 합성 및 형성기구 규명)

  • Heo, H.B.;Shin, K.C.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • 제4권2호
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    • pp.178-189
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    • 1994
  • Fine $BaTiO_3$ powder was synthesized from the various starting solution with 0.05 M by ultrasonic spray pyrolysis method. The conditions of synthesis were fixed on flow rate was 0.5 cm/sec, low temperature furnace was $300^{\circ}C$, and high temperatures furnace was $700^{\circ}C$. The formation procedure was investigated directly by SEM with the collected particle from the each reaction step. Also, the trace of particle in reaction tube was researched theoretically. Fine $BaTiO_3$ was synthesized only in the case of nitrate aqueous solution. The synthesized $BaTiO_3$ powder was porous and spherical which was consist of primary particle at the size of 19.1 nm. The formation procedure was as follows : the particle size decreased in drying step and then increased in initial thermal decomposition step. Finally, particle size was decreased to $0.42 {mu}m$. The trace of particle in reaction tube was also theoretically simulated and discussed.

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MMPP is a novel VEGFR2 inhibitor that suppresses angiogenesis via VEGFR2/AKT/ERK/NF-κB pathway

  • Na-Yeon Kim;Hyo-Min Park;Jae-Young Park;Uijin Kim;Ha Youn Shin;Hee Pom Lee;Jin Tae Hong;Do-Young Yoon
    • BMB Reports
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    • 제57권5호
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    • pp.244-249
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    • 2024
  • Many types of cancer are associated with excessive angiogenesis. Anti-angiogenic treatment is an effective strategy for treating solid cancers. This study aimed to demonstrate the inhibitory effects of (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP) in VEGFA-induced angiogenesis. The results indicated that MMPP effectively suppressed various angiogenic processes, such as cell migration, invasion, tube formation, and sprouting of new vessels in human umbilical vein endothelial cells (HUVECs) and mouse aortic ring. The inhibitory mechanism of MMPP on angiogenesis involves targeting VEGFR2. MMPP showed high binding affinity for the VEGFR2 ATP-binding domain. Additionally, MMPP improved VEGFR2 thermal stability and inhibited VEGFR2 kinase activity, suppressing the downstream VEGFR2/AKT/ERK pathway. MMPP attenuated the activation and nuclear translocation of NF-κB, and it downregulated NF-κB target genes such as VEGFA, VEGFR2, MMP2, and MMP9. Furthermore, conditioned medium from MMPP-treated breast cancer cells effectively inhibited angiogenesis in endothelial cells. These results suggested that MMPP had great promise as a novel VEGFR2 inhibitor with potent anti-angiogenic properties for cancer treatment via VEGFR2/AKT/ERK/NF-κB signaling pathway.

Crytallization Behavior of Amorphous ${Si_{1-x}}{Ge_x)$ Films Deposited on $SiO_2$ by Molecular Beam Epitaxy(MBE) ($SiO_2$위에 MBE(Moleculat Beam Epitaxy)로 증착한 비정질 ${Si_{1-x}}{Ge_x)$박막의 결정화거동)

  • Hwang, Jang-Won;Hwang, Jang-Won;Kim, Jin-Won;Kim, Gi-Beom;Lee, Seung-Chang;Kim, Chang-Su
    • Korean Journal of Materials Research
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    • 제4권8호
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    • pp.895-905
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    • 1994
  • The solid phase crystallization behavior of undoped amorphous $Si_{1-x}Ge_{x}$ (X=O to 0.53) alloyfilms was studied by X-ray diffractometry(XRD) and transmission electron microscopy(TEM). Thefilms were deposited on thermally oxidized 5" (100) Si wafer by MBE(Mo1ecular Beam Epitaxy) at 300'C and annealed in the temperature range of $500^{\circ}C$ ~ $625^{\circ}C$. From XRD results, it was found that the thermal budget for full crystallization of the film is significantly reduced as the Ge concentration in thefilm is increased. In addition, the results also shows that pure amorphous Si film crystallizes with astrong (111) texture while the $Si_{1-x}Ge_{x}$ alloy film crystallzes with a (311) texture suggesting that the solidphase crystallization mechanism is changed by the incorporation of Ge. TEM analysis of the crystallized filmshow that the grain morphology of the pure Si is an elliptical and/or a dendrite shape with high density ofcrystalline defects in the grains while that of the $Si_{0.47}Ge_{0.53}$ alloy is more or less equiaxed shape with muchlower density of defects. From these results, we conclude that the crystallization mechanism changes fromtwin-assisted growth mode to random growth mode as the Ge cocentration is increased.ocentration is increased.

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Hydrogen and Ethanol Gas Sensing Properties of Mesoporous P-Type CuO

  • Choi, Yun-Hyuk;Han, Hyun-Soo;Shin, Sun;Shin, Seong-Sik;Hong, Kug-Sun
    • Proceedings of the Korean Vacuum Society Conference
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    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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    • pp.222-222
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    • 2012
  • Metal oxide gas sensors based on semiconductor type have attracted a great deal of attention due to their low cost, flexible production and simple usability. However, most works have been focused on n-type oxides, while the characteristics of p-type oxide gas sensors have been barely studied. An investigation on p-type oxides is very important in that the use of them makes possible the novel sensors such as p-n diode and tandem devices. Monoclinic cupric oxide (CuO) is p-type semiconductor with narrow band gap (~1.2 eV). This is composed of abundant, nontoxic elements on earth, and thus low-cost, environment-friendly devices can be realized. However, gas sensing properties of neat CuO were rarely explored and the mechanism still remains unclear. In this work, the neat CuO layers with highly ordered mesoporous structures were prepared by a template-free, one-pot solution-based method using novel ink solutions, formulated with copper formate tetrahydrate, hexylamine and ethyl cellulose. The shear viscosity of the formulated solutions was 5.79 Pa s at a shear rate of 1 s-1. The solutions were coated on SiO2/Si substrates by spin-coating (ink) and calcined for 1 h at the temperature of $200{\sim}600^{\circ}C$ in air. The surface and cross-sectional morphologies of the formed CuO layers were observed by a focused ion beam scanning electron microscopy (FIB-SEM) and porosity was determined by image analysis using simple computer-programming. XRD analysis showed phase evolutions of the layers, depending on the calcination temperature, and thermal decompositions of the neat precursor and the formulated ink were investigated by TGA and DSC. As a result, the formation of the porous structures was attributed to the vaporization of ethyl cellulose contained in the solutions. Mesoporous CuO, formed with the ink solution, consisted of grains and pores with nano-meter size. All of them were strongly dependent on calcination temperature. Sensing properties toward H2 and C2H5OH gases were examined as a function of operating temperature. High and fast responses toward H2 and C2H5OH gases were discussed in terms of crystallinity, nonstoichiometry and morphological factors such as porosity, grain size and surface-to-volume ratio. To our knowledge, the responses toward H2 and C2H5OH gases of these CuO gas sensors are comparable to previously reported values.

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