• 제목/요약/키워드: Biomedical Engineering

검색결과 7,055건 처리시간 0.029초

Cordycepin (3'-deoxyadenosine) Has an Anti-platelet Effect by Regulating the cGMP-Associated Pathway of Human Platelet Activation

  • Cho, Hyun-Jeong;Rhee, Man-Hee;Cho, Jae-Youl;Kim, Hyeong-Soo;Ok, Woo-Jeong;Kang, Hee-Jin;Park, Hwa-Jin
    • Preventive Nutrition and Food Science
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    • 제12권3호
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    • pp.141-147
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    • 2007
  • Cordycepin (3'-deoxyadenosine), which comes from Cordyceps militaris, the Chinese medicinal fungal genus Cordyceps, is used in the treatment of various diseases such as cancer and chronic inflammation. We recently reported that cordycepin has a novel antiplatelet effect through the down regulation of $[Ca^{2+}]_{i}$ and the elevation of cGMP/cAMP production. In this study, we further investigated the effect of cordycepin on collagen-induced platelet aggregation in the presence of cGMP-dependent protein kinase (PKG)- or cAMP-dependent protein kinase (PKA)-inhibitor. PKG inhibitor Rp-8-pCPT-cGMPS potentiated the collagen-induced platelet aggregation, but PKA inhibitor Rp-8-Br-cAMPS did not. However, both Rp-8-pCPT-cGMPS and Rp-8-Br-cAMPS reduced inhibition by cordycepin of collagen-induced platelet aggregation. Moreover, cordycepin inhibited $Ca^{2+}-dependent$ phosphorylation of both 47 kDa- and 20 kDa-protein in the presence of both PKG inhibitor and PKA inhibitor. Taken altogether, these results suggest that the inhibitory effect of cordycepin on collagen-induced platelet aggregation is associated with cGMP/PKG- and cAMP/PKA-pathways, and thus cordycepin may be an efficacious intervention against platelet aggregation-mediated thrombotic disease.

해조류 유래 호흡기 질환 천식 치료제 연구 동향 (A Review of Marine Algae-derived Therapeutic Agents for Respiratory Disease Asthma)

  • 김태희;허성영;오건우;김민성;최일환;정원교
    • 한국해양바이오학회지
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    • 제12권1호
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    • pp.1-10
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    • 2020
  • Asthma is a complex inflammatory disease of the lung characterized by variable airflow obstruction, airway hyperresponsiveness, airway inflammation, and reduction of respiratory function. Its prevalence and incidence are increasing because of the effect of various environmental and lifestyle risk factors. Steroid inhalation, long-acting agonists, and other synthetic drugs are used for the treatment of this disease. However, they have some side effects and show unsatisfied result and response after treatment. Therefore, many researchers have focused on the development of natural product-related treatment for asthma to suppress the side effects and unsatisfied results. Seaweeds contain various bioactive compounds with anti-inflammatory, antibacterial, and anti-oxidant activities. Thus, we investigated the asthma treatment-related literature using marine algae via the Google scholar search engine. Consequently, the literature is rarely investigated, but is increasing steadily. The literature was performed as a comparison study with an ovalbumin-induced group or drug-treated group, and investigated the antiasthma activity of algae ethanol extract. Although many researchers have studied marine algae-derived therapeutic agents for asthma, the amount of literature is rare compared with those of herbal medicine-derived therapeutic agents. Conclusively, we suggest that many researchers should investigate and develop algae-derived therapeutic agents for asthma treatment.

DAMGO modulates two-pore domain K+ channels in the substantia gelatinosa neurons of rat spinal cord

  • Cho, Pyung Sun;Lee, Han Kyu;Lee, Sang Hoon;Im, Jay Zoon;Jung, Sung Jun
    • The Korean Journal of Physiology and Pharmacology
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    • 제20권5호
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    • pp.525-531
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    • 2016
  • The analgesic mechanism of opioids is known to decrease the excitability of substantia gelatinosa (SG) neurons receiving the synaptic inputs from primary nociceptive afferent fiber by increasing inwardly rectifying $K^+$ current. In this study, we examined whether a ${\mu}$-opioid agonist, [D-Ala2,N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO), affects the two-pore domain $K^+$ channel (K2P) current in rat SG neurons using a slice whole-cell patch clamp technique. Also we confirmed which subtypes of K2P channels were associated with DAMGO-induced currents, measuring the expression of K2P channel in whole spinal cord and SG region. DAMGO caused a robust hyperpolarization and outward current in the SG neurons, which developed almost instantaneously and did not show any time-dependent inactivation. Half of the SG neurons exhibited a linear I~V relationship of the DAMGO-induced current, whereas rest of the neurons displayed inward rectification. In SG neurons with a linear I~V relationship of DAMGO-induced current, the reversal potential was close to the $K^+$ equilibrium potentials. The mRNA expression of TWIK (tandem of pore domains in a weak inwardly rectifying $K^+$ channel) related acid-sensitive $K^+$ channel (TASK) 1 and 3 was found in the SG region and a low pH (6.4) significantly blocked the DAMGO-induced $K^+$ current. Taken together, the DAMGO-induced hyperpolarization at resting membrane potential and subsequent decrease in excitability of SG neurons can be carried by the two-pore domain $K^+$ channel (TASK1 and 3) in addition to inwardly rectifying $K^+$ channel.

SiMACS에서의 생체신호처리 및 데이터관리 (Signal Processing and Data Management in SiMACS)

  • 서재준;김중진;이수병;박승훈;우응제
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1994년도 춘계학술대회
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    • pp.57-59
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    • 1994
  • In this paper, we present the software part of the intelligent data processing unit (IDPU), which plays an important role in SiMACS. The software system processes ECG, EEG, EMG, blood pressure, respiration, temperature signals, and extracts some information about patient conditions. It displays the patient condition information and the signal data synchronously, and manages them together with other patient personal data in a network-based client/server environment. The software system is designed in an object-oriented paradigm, and implemented in C++ as a window-based application program.

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근적외선 분광법 및 확산 광 영상법의 최근 연구 동향 (Medical Applications of Near Infrared Spectroscopy and Diffuse Optical Imaging (Review))

  • 이승덕;권기운;고달권;김법민
    • 대한의용생체공학회:의공학회지
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    • 제29권2호
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    • pp.89-98
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    • 2008
  • NIRS (Near-infrared Spectroscopy) and DOI (Diffuse Optical Imaging) are relatively new, non-invasive, and non-ionizing methods that measure or image optical properties (Scattering and Absorption Coefficient) and physiological properties (Water Fraction, concentration of Oxy-, Deoxy-Hemoglobin, Cytochrome Oxidase, etc) of biological tissues. In this paper, three different types of NIRS systems, mathematical modeling, and reconstruction algorithms are described. Also, recent applications such as functional brain imaging, optical mammography, NIRS based BMI (Brain-Machine Interface), and small animal study are reviewed.

Computer Model for Fibrinogen Adsorption on Polyurethane Surface

  • Kim, Jong-Won;Shin, In-Sun;Ryu, Gyu-Ha;Lee, Kyu-Back;Han, Dong-Keun;Kim, Young-Ha;Min, Byoung-Goo
    • 대한의용생체공학회:의공학회지
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    • 제15권1호
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    • pp.51-56
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    • 1994
  • Protein adsorption on the polyurethane surface was modelled by a modified random sequential adsorption(RSA) process. In this model, polyurethane surface was modelled as a mixed domain of hydrophobic and hydrophilic parts which was implemented by a 2 dimensional $150{\times}150$ lattice in the computer. Protein adsorption was simulated using a small box which represents a particle of the protein, and polyurethane lattice by considering their hydrophobic interaction. In order to validate the model, we perfonned fibrinogen adsorption on polyurethane surface. Isotherms of the adsorbed protein were calculated and compared to the experimental data. The protein adsorption on the polyurethane surface could be well described using this computer model.

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초음파 영상용 플라스틱 기반의 팬텀제작 및 특성 분석 (Analysis of Properties and Phantom Design Based on Plastic Hardener and Softener for Ultrasonic Imaging)

  • 이균정;박동희;신태민;서종범
    • 대한의용생체공학회:의공학회지
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    • 제29권4호
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    • pp.302-306
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    • 2008
  • Plastic hardener and softener based ultrasound phantoms were made in various constitutions and their acoustic properties were measured. Speed of sound is approximately $1.4\;mm/{\mu}sec$ in all the phantoms, which is about 7% less than that of in soft tissue. Attenuation coefficient is strongly dependent on the ratio between hardener and softener. In order to achieve the tissue level attenuation (0.5 dB/cm/MHz), 60% of hardener or less is required. The synthesized phantoms can be preserved for more than 6 months without structural degradation.

Characterization of Antithrombotic Activity of Lumbrokinase immobilized Polyurethane Heart Valves in Total Artificial Heart Experiment

  • 박용두;정재승;김현정;김종원;민병구
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1997년도 춘계학술대회
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    • pp.51-54
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    • 1997
  • Lumbrokinase, potent fibrinolytic enzyme purified from earthworm, was immobilized onto the total artificial heart valves using photoreaction. This valve were implanted into the lamb for three days. After experiments, thrombus was observed in the untreated valves whereas no thrombus was observed in the lumbrokinase immobilized valves. The fibrinolytic activity and proteolytic activity of the implanted valve was examined. The fibrinolytic activity of the valve was remained after the implantation. The lumbrokinase could be a suitable fibrinolytic agents in the vascular contacting devices to reduce the thrombus.

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스마트폰 기반의 휴대용 PPG센서 개발 (Development of portable PPG sensor based on smart phone)

  • 김정한;조경래;김상윤;강성인;배성호
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2013년도 춘계학술대회
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    • pp.1009-1011
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    • 2013
  • 최근 U-헬스케어 서비스가 증가함에 따라 예방과 건강증진 등에 관심과 연구가 활발히 이루어지고 있다. 이러한 U-헬스케어에 사용되는 ECG, EMG, PPG EEG등이 스마트폰 기반의 휴대용 장비와 연동된 센서들의 연구 역시 활발히 진행 중이다. 일반적으로 PPG신호는 적외선센서를 이용하여 모세혈관의 혈중 헤모글로빈 농도 변화에 의한 맥파를 측정한다. PPG신호의 잡음을 제거하기 위해 필터를 사용하였다. 필터된 정보를 ADC하여 스마트폰으로 BlueTooth통신을 이용하여 전송한다. 최종적으로 스마트 디바이스에 PPG신호를 그린다. 제작결과 PPG아날로그 신호를 보는 것과 동일하게 스마트 디바이스에 그릴 수 있음을 보였다. 이후 PPG신호를 이용하여 혈관건강도 및 건강예방의 측정의 연구를 계속해서 한다.

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