• Title/Summary/Keyword: Induced current

Search Result 2,684, Processing Time 0.03 seconds

Control of $Ca^{2+}$- Influx by $Ca^{2+}$/Calmodulin Dependent Protein Kinase II in the Activation of Mouse Eggs

  • Yoon, Sook-Young;Kang, Da-Won;Bae, In-Ha
    • Development and Reproduction
    • /
    • v.15 no.1
    • /
    • pp.31-39
    • /
    • 2011
  • Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

Experimental Analysis of Vibration Transfer Characteristics of an Elevated Railroad Station (철도 선하역사 진동 전달 특성의 실험적 분석)

  • Choi, Sanghyun;Yoo, Yong;Kim, Jinho;Kwon, Segon
    • Journal of the Society of Disaster Information
    • /
    • v.11 no.1
    • /
    • pp.89-96
    • /
    • 2015
  • To reduce noise inside an elevated railroad station, the vibration of the station structure should be lowered, and to establish more effective anti-vibration measures it is required that, reflecting the track-bridge-structure interaction, the transfer characteristics of vibration induced by a train is well identified. In this paper, the current status of domestic railroad stations is classified, and the vibration transfer characteristics is analyzed via measurement data from representative elevated stations. From the analysis results on the measurement data, in transferring vibration from the track to the structure, remarkable vibration reduction in higher frequency range is observed, and, in some stations, amplified response characteristics in lower frequency range is identified. Also, for stations with floating track system or TPS type, relatively greater reduction in transferred vibration is observed.

A Study on the Recycling Package Design (재활용 포장디자인의 연구 - 마케팅을 중심으로 -)

  • 재활용
    • Archives of design research
    • /
    • v.21
    • /
    • pp.139-147
    • /
    • 1997
  • The concept of package in these day is getting changing with fluctuation of living and management circumstance. The is due to society trancefiguration and change of economic structure and induced to appear small paxkage. These package trend to covert from the class management to total management system and these system made a promotion to development current industry. In these day, with the development of industry and the progress of the life , the package is performing the first faculty such as perservation of manufacture, convenience of keeping and loading in , expedition of sale and additionally the role of package in modern economy is significant for the essen tial element of enterprise prosperity by improving its shape color and materials. It is readilly appearent to anyone in the recycling field that stable markets for collected materials are vitals to any successful program. The recycling movement has increased in popularity throughout the any country: however, it has brought with it a market for them. This attitute also prevails in the political arena where atates or municipalities who are committed to recycling major portion of the solid waste stream are asking these same question regarding the disposition of thte recycled material.

  • PDF

Cryopreservation of Chrysanthemum morifolium cv. 'White ND' Shoot Tips using Encapsulation-Dehydration-Vitrification Method (캡슐화-탈수화-유리화에 의한 국화 품종 '화이트 엔디' 신초의 초저온 동결보존)

  • Jeon, Su Min;Kim, Chang Kil
    • Current Research on Agriculture and Life Sciences
    • /
    • v.32 no.2
    • /
    • pp.99-103
    • /
    • 2014
  • This study investigated the effects of cryopreserving Chrysanthemum morifolium cv. 'White ND' shoot tips for eliminating viroids. As a result, smaller shoot tips (2-3 LP, 1mm) showed a better survival and regrowth than larger shoot tips (4-5 LP, 1.5mm). The most effective vitrification solution for survival and regrowth was PVS3, which induced a high survival rate after 60 minutes of incubation. For a high efficiency, the best pre-treatment condition for vitrification was incubation in 88 mM sucrose for 24 h, 0.3M sucrose for 16 h, 0.5 M sucrose for 6 h, and 0.7 M sucrose for 3 h, in a descending order. The ploidy levels were the same in the mother plants and following cryopreservation, which confirmed the absence of any gene mutation.

Blockade of Kv1.5 by paroxetine, an antidepressant drug

  • Lee, Hyang Mi;Hahn, Sang June;Choi, Bok Hee
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.20 no.1
    • /
    • pp.75-82
    • /
    • 2016
  • Paroxetine, a selective serotonin reuptake inhibitor (SSRI), has been reported to have an effect on several ion channels including human ether-a-go-go-related gene in a SSRI-independent manner. These results suggest that paroxetine may cause side effects on cardiac system. In this study, we investigated the effect of paroxetine on Kv1.5, which is one of cardiac ion channels. The action of paroxetine on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Paroxetine reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an $IC_{50}$ value and a Hill coefficient of $4.11{\mu}M$ and 0.98, respectively. Paroxetine accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance ${\delta}$ of 0.32. The binding ($k_{+1}$) and unbinding ($k_{-1}$) rate constants for paroxetine-induced block of Kv1.5 were $4.9{\mu}M^{-1}s^{-1}$ and $16.1s^{-1}$, respectively. The theoretical $K_D$ value derived by $k_{-1}/k_{+1}$ yielded $3.3{\mu}M$. Paroxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of paroxetine, were superimposed. Inhibition of Kv1.5 by paroxetine was use-dependent. The present results suggest that paroxetine acts on Kv1.5 currents as an open-channel blocker.

The effect of μ-opioid receptor activation on GABAergic neurons in the spinal dorsal horn

  • Kim, Yoo Rim;Shim, Hyun Geun;Kim, Chang-Eop;Kim, Sang Jeong
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.22 no.4
    • /
    • pp.419-425
    • /
    • 2018
  • The superficial dorsal horn of the spinal cord plays an important role in pain transmission and opioid activity. Several studies have demonstrated that opioids modulate pain transmission, and the activation of ${\mu}$-opioid receptors (MORs) by opioids contributes to analgesic effects in the spinal cord. However, the effect of the activation of MORs on GABAergic interneurons and the contribution to the analgesic effect are much less clear. In this study, using transgenic mice, which allow the identification of GABAergic interneurons, we investigated how the activation of MORs affects the excitability of GABAergic interneurons and synaptic transmission between primary nociceptive afferent and GABAergic interneurons. We found that a selective ${\mu}$-opioid agonist, [$D-Ala^2$, $NMe-Phe^4$, Gly-ol]-enkephanlin (DAMGO), induced an outward current mediated by $K^+$ channels in GABAergic interneurons. In addition, DAMGO reduced the amplitude of evoked excitatory postsynaptic currents (EPSCs) of GABAergic interneurons which receive monosynaptic inputs from primary nociceptive C fibers. Taken together, we found that DAMGO reduced the excitability of GABAergic interneurons and synaptic transmission between primary nociceptive C fibers and GABAergic interneurons. These results suggest one possibility that suppression of GABAergic interneurons by DMAGO may reduce the inhibition on secondary GABAergic interneurons, which increase the inhibition of the secondary GABAergic interneurons to excitatory neurons in the spinal dorsal horn. In this circumstance, the sum of excitation of the entire spinal network will control the pain transmission.

Chemical Shift Artifact Correction in MREIT

  • Minhas, Atul S.;Kim, Young-Tae;Jeong, Woo-Chul;Kim, Hyung-Joong;Lee, Soo-Yeol;Woo, Eung-Je
    • Journal of Biomedical Engineering Research
    • /
    • v.30 no.6
    • /
    • pp.461-468
    • /
    • 2009
  • Magnetic resonance electrical impedance tomography (MREIT) enables us to perform high-resolution conductivity imaging of an electrically conducting object. Injecting low-frequency current through a pair of surface electrodes, we measure an induced magnetic flux density using an MRI scanner and this requires a sophisticated MR phase imaging method. Applying a conductivity image reconstruction algorithm to measured magnetic flux density data subject to multiple injection currents, we can produce multi-slice cross-sectional conductivity images. When there exists a local region of fat, the well-known chemical shift phenomenon produces misalignments of pixels in MR images. This may result in artifacts in magnetic flux density image and consequently in conductivity image. In this paper, we investigate chemical shift artifact correction in MREIT based on the well-known three-point Dixon technique. The major difference is in the fact that we must focus on the phase image in MREIT. Using three Dixon data sets, we explain how to calculate a magnetic flux density image without chemical shift artifact. We test the correction method through imaging experiments of a cheese phantom and postmortem canine head. Experimental results clearly show that the method effectively eliminates artifacts related with the chemical shift phenomenon in a reconstructed conductivity image.

Indications, Outcomes, and Complications of Pedicled Propeller Perforator Flaps for Upper Body Defects: A Systematic Review

  • Lazzeri, Davide;Huemer, Georg M.;Nicoli, Fabio;Larcher, Lorenz;Dashti, Talal;Grassetti, Luca;Li, Qingfeng;Zhang, Yixin;Spinelli, Giuseppe;Agostini, Tommaso
    • Archives of Plastic Surgery
    • /
    • v.40 no.1
    • /
    • pp.44-50
    • /
    • 2013
  • Background The aim of this investigation was to systematically review the current literature to provide the best data for indications, outcomes, survival, and complication rates of pedicled propeller perforator flaps for upper body defects. Methods A comprehensive literature review for articles published from January 1991 to December 2011 was performed using the PubMed, Medline, and Cochrane Databases. Articles without available full-text, single case reports or papers with excessive missing data were excluded. Papers reporting pedicle-perforator (propeller) flaps used for lower extremity reconstruction were excluded from meta-analysis. Results From the initial 1,736 studies our search yielded, 343 studies qualified for the second stage of selection. Of 117 full-text reports screened, 41 studies, met the definitive inclusion and exclusion criteria. Of the selected 41 articles, 26 were case series, original papers or retrospective reviews and were included, whereas 15 were case report papers and therefore were excluded. Two hundred ninety-five propeller flaps were reported to have been used in a total of 283 patients. Indications include repair of trauma-induced injuries, post-trauma revision surgery, cancer resection, chronic infection, pressure sores, and chronic ulcers with a major complication rate (3.3%) comparable to that of free flaps. No specific exclusion criteria for the procedure were presented in the studies reviewed. Conclusions Pedicled propeller flaps are a versatile and safe reconstructive option that are easy and quick to raise and that provide unlimited clinical solutions because of the theoretical possibility of harvesting them based on any perforator chosen among those classified in the body.

Recent Molecular Studies of Marek's Disease Virus and Control Approaches for Increasing Virulence (마렉병 바이러스의 분자적 병리기전과 증가하는 병원성에 대한 제어 방안)

  • Jang, H.K.;Park, Y.M.;Cha, S.Y.;Kwon, J.T.
    • Korean Journal of Poultry Science
    • /
    • v.34 no.1
    • /
    • pp.57-76
    • /
    • 2007
  • Marek's disease (MD) is caused by a ubiquitous, lymphotropic alphaherpesvirus, MD virus (MDV). MD has been a major concern in the poultry industry due to the emergence of increasingly virulent strains over the last few decades that were isolated in the face of comprehensive vaccination. MD is characterized by a variety of clinical signs, amongst them neurological symptoms, chronic wasting, and most notably the development of multiple lymphomas that manifest as solid tumors in the viscera and musculature. Much work has been devoted to study MD-induced oncogenesis and genes involved in this process. Among the many genes encoded by MDV, a number have recently been shown to affect the development of tumors in chickens, one protein directly causing transformation of cells (Meq) and another being involved in maintaining transformed cells (vTR). Other MDV gene products modulate and are involved in early lytic in vivo replication, thereby increasing the chance of transformation occurring. In this review, specific genes encoded by MDV that are involved in the initiation and/or maintenance of transformation were briefly summarized, and limits of current vaccination and new control strategies against MD, particularly how modem molecular biological methods may be used to improve strategies to combat the disease in the future, were discussed.

Skin Permeability of piroxicam Gel by Phonophoretic Transdermal Drug Delivery (음파영동 경피약물수송에 의한 Piroxicam Gel의 경피투과)

  • Choi Suk-Joo;Oh Myung-Hwa;Kim Tae-Youl
    • The Journal of Korean Physical Therapy
    • /
    • v.14 no.4
    • /
    • pp.147-162
    • /
    • 2002
  • Transdermal permeation enhancer has been used to increased skin absorption. External control of drug release and skin absorption can also be achieved by iontophoresis or phonophoresis. However, because several problems with iontophoresis are that it has a risk to skin damage because of the change of pH and the increase of current density in applying it and that it can be applied only in the form of water solution, This study is to enhance drug permeation via skin following application of ultrasound. For this goal, in gel containing piroxicam, the degree of skin permeation in vitro and anti-inflammatory effect in in vivo were investigated. Permeation study using hairless mouse skin was performed at 37 $^{\circ}C$ using buffer saline as the receptor solution. The amount of piroxicam were quantified using a HPLC system consisting of solvent delivery system. Following adoption of ultrasound 1 MHZ, it showed relatively high permeation rate where it was compared with non treated by ultrasound. The influence of duty cycle having an effect on skin permeation rate was slight higher in the case of using pulsed mode. Skin permeation increase attended by intensity of ultrasound, the permeation of trice was accelerated at 2.0 W/$cm^{2}$ than 1.0 W/$cm^{2}$. The skin permeation of piroxicam was substantially influenced by ultrasound. Anti-inflammatory effects were determined using carrageenan-induced paw swelling method in SD rat. Paw swelling tests showed that pulsed phonophoresis group was more effective than control group and only gel application group. The conclusion of phonophoresis was found to improve significantly the skin permeation in vitro and the anti-inflammatory effect in vivo.

  • PDF