• 제목/요약/키워드: Biological tissue

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자동제어 측정 시스템을 이용한 생체 조직의 임피던스 평가 (Evaluation of Impedance on Biological Tissues Using Automatic Control Measurement System)

  • 길상형;이무석;김상식;신동훈;이성모;김군도;이종규
    • 비파괴검사학회지
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    • 제35권4호
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    • pp.239-244
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    • 2015
  • 생체 조직은 세포 배열이나 조직 형태 등 다양한 차이에 의해 각각 고유의 전기적 특성을 가지며, 생물학적 변화가 일어나면 고유의 전기적 특성이 변한다. 본 연구는 방사선 피폭에 따른 생체 조직의 전기적 특성 변화를 측정하기 위한 선행연구로 측정 과정에서 방사선 피폭 우려가 있으므로, 실험자의 방사선 장애를 방지하기 위해 LabVIEW를 이용하여 자동제어 측정 시스템을 개발한 후 생체 조직의 특성을 평가하고자 하였다. 생체 조직의 전기적 특성 측정전 후 형태학적 변화를 관찰한 결과 조직 변화는 관찰되지 않았으며, 유사한 양상이었다. Impedance/Gain-phase analyzer로 생체 조직의 임피던스를 반복 측정한 결과 변동계수가 10% 미만으로 측정값은 재현성이 있었다. 주파수 변화에 따른 생체 조직의 전기적 특성 중에서 위상차 변화는 거의 없었으며, 조직은 저항성을 나타내었고, 임피던스 크기는 주파수에 비례하여 일정하게 감소하였다. 본 연구를 통해 생체 조직의 전기적 특성 변화를 측정할 수 있는 자동제어 시스템을 개발하였으며, 생체 조직의 전기적 특성을 이해할 수 있었다.

생체조직의 광학적 흡수계수 측정에 관한 연구 (A Study on Measurements of Optical Absorption Coefficients of Biological tissue)

  • 임현수;김남중
    • 대한의용생체공학회:의공학회지
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    • 제20권2호
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    • pp.213-220
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    • 1999
  • 본 연구는 쥐의 뇌, 심장, 간, 근육 및 근육부위의 종양조직과 인간의 뇌 조직과 뇌 종양 조직의 광학적 흡수계수를 500nm~900nm 범위의 파장에서 측정하고 비교분석하였다. 광학적 흡수계수는 물질마다 가지고 있는 고유한 성질을 나타내므로 생체조직의 광학계수를 측정하면, 생체 조직의 고유한 특성을 나타낼 수 있다. Spectrograph monometer와 PDA를 이용하여, 동결절편으로 제작한 시편에 대하여 실험하였다. 실험결과, 쥐 조직과 인체의 뇌 조직의 흡수계수는 정상적인 일반 조직과 종양 조직에서 차이가 분명하게 있음을 알 수 있었다. 정상 뇌 조직의 흡수계수는 파장이 변화함에 따라 0.1~0.2$cm^{-1}$사이의 비교적 균일한 값을 보이는데 반하여, 뇌종양 조직의 흡수계수는 파장에 따라서 크게는 약 0.4~0.5$cm^{-1}$정도의 변화가 있다. 본 실험 결과들은 다양한 조직에서의 광학계수 중에서 흡수계수를 측정함으로써, 생체조직의 흡수계수의 변화를 감지하여 질병진단의 지표로 삼을 수 있다.

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고분자 생체재료와 줄기세포를 이용한 조직공학과 재생의학의 최신 동향 (Recent Applications of Polymeric Biomaterials and Stem Cells in Tissue Engineering and Regenerative Medicine)

  • 이상진
    • 폴리머
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    • 제38권2호
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    • pp.113-128
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    • 2014
  • Tissue engineering and regenerative medicine strategies could offer new hope for patients with serious tissue injuries or end-stage organ failure. Scientists are now applying the principles of cell transplantation, material science, and engineering to create biological substitutes that can restore and maintain normal function in diseased or injured tissues/organs. Specifically, creation of engineered tissue construct requires a polymeric biomaterial scaffold that serves as a cell carrier, which would provide structural support until native tissue forms in vivo. Even though the requirements for scaffolds may be different depending on the target applications, a general function of scaffolds that need to be fulfilled is biodegradability, biological and mechanical properties, and temporal structural integrity. The scaffold's internal architecture should also enhance the permeability of nutrients and neovascularization. In addition, the stem cell field is advancing, and new discoveries in tissue engineering and regenerative medicine will lead to new therapeutic strategies. Although use of stem cells is still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous adult cells have already entered the clinic. This review discusses these tissue engineering and regenerative medicine strategies for various tissues and organs.

Functional Enhancers As Master Regulators of Tissue-Specific Gene Regulation and Cancer Development

  • Ko, Je Yeong;Oh, Sumin;Yoo, Kyung Hyun
    • Molecules and Cells
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    • 제40권3호
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    • pp.169-177
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    • 2017
  • Tissue-specific transcription is critical for normal development, and abnormalities causing undesirable gene expression may lead to diseases such as cancer. Such highly organized transcription is controlled by enhancers with specific DNA sequences recognized by transcription factors. Enhancers are associated with chromatin modifications that are distinct epigenetic features in a tissue-specific manner. Recently, super-enhancers comprising enhancer clusters co-occupied by lineage-specific factors have been identified in diverse cell types such as adipocytes, hair follicle stem cells, and mammary epithelial cells. In addition, noncoding RNAs, named eRNAs, are synthesized at super-enhancer regions before their target genes are transcribed. Many functional studies revealed that super-enhancers and eRNAs are essential for the regulation of tissue-specific gene expression. In this review, we summarize recent findings concerning enhancer function in tissue-specific gene regulation and cancer development.

Growth dynamics of the seagrass, Zostera marina in Jindong Bay on the southern coast of Korea

  • Kim, Young-Kyun;Kim, Jong-Hyeob;Kim, Seung-Hyeon;Kim, Jae-Woo;Park, Sang-Rul;Lee, Kun-Seop
    • ALGAE
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    • 제27권3호
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    • pp.215-224
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    • 2012
  • Growth dynamics of the seagrass, Zostera marina were examined at the two stations (Myungju and Dagu) in Jindong Bay on the southern coast of Korea. Eelgrass leaf productivities, underwater irradiance, water temperature, dissolved inorganic nitrogen (DIN) in water column and sediments, and tissue carbon (C) and nitrogen (N) content were monitored monthly from March 2002 to January 2004. Underwater irradiance fluctuated highly without a clear seasonal trend, whereas water temperature showed a distinct seasonal trend at both study stations. Water column DIN concentrations were usually less than $5{\mu}M$ at both study sites. Sediment pore water $NH_4{^+}$ and $NO_3{^-}+NO_2{^-}$ concentrations were higher at the Myungju site than at the Dagu site. Eelgrass leaf productivity at both study sites exhibited a distinct seasonality, increasing during spring and decreasing during summer. Seasonal variation of eelgrass productivity was not consistent with seasonal patterns of underwater irradiance, or water temperature. Eelgrass tissue C and N content at both study sites also showed significant seasonal variations. Relationships between tissue C and N content and leaf productivities exhibited usually negative correlations at both study sites. These negative correlations implied that the growth of Z. marina at the study sites was probably limited by C and N supplies during the high growth periods.

가열과 운동에 의한 생체조직내의 생리적 변화에 따른 광학적 특성의 변화에 관한 연구 (The Effects of Physiological Heating and Exercise on the Optical Properties of Biological Tissue.)

  • 임현수;허웅
    • 대한의용생체공학회:의공학회지
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    • 제14권1호
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    • pp.81-88
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    • 1993
  • This paper is the study of the reflectance of light from biological tissue for red and Infrared wavelengths and relates the acquired reflectance data to expected physiological changes within the skin and muscle layers associated with heat and exercise. The instrument was disigned to collect data from the calf muscle in human subjects with probe located at the surface of skin. Rapid data acquisition method allowed monitoring of rapid changes in reflecttance due to a stimulus. This study demonstrates that changes in O2 saturation and blood fractional volume expected within the dermis and muscle layers were asserted by examining the slopes of the plotted index for heat and exercise. The results presented in thls study support the claim that reflectance can separately discriminate between changes of blood volume and oxygenation in muscle and in skin. The data demonstrate the ability to measure consistent changes In tissue optical properties during exercise and heat.

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생체내의 초음파 감쇄계수를 측정하기 위한 초음파 신호스펙트럼 특성에 관한 연구 (A Study on Spectral Characteristics of Ultrasonic Signal for Tissue Attennation Coefficient Measurement)

  • 허웅
    • 대한의용생체공학회:의공학회지
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    • 제4권1호
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    • pp.29-36
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    • 1983
  • In this paper, center frequency down slift of ultrasonic echo signals which for the measurements of frequency dependent attenuation in the biological tissue are estimated. Center frequency down shift of echo-signals are estimated after signal spectrum analysis of whole echo-signals. In case of signal spectrums are simple, estimation of down shift frequency is very simple and in case of complicate spectrum, estimation of down shift frequency is depend on spectral shape. In case of unable to estimate, frequency dependence of medium is nonlinear(n) 1), in which upper shift of spectrums are presented. In case of unable to estimate, spectrum analysis are performed at local position. At consquence, we know that spectral dispersions are caused complicately by biological tissue layer.

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레이저 파장에서의 생체 침습적 및 비침습적 광학계수 측정 방법 (Invasive and non-invasive methods for estimating the optical properties of tissue at laser wavelengths)

  • 윤길원
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1994년도 추계학술대회
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    • pp.147-150
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    • 1994
  • To predict light propagation in biological tissues irradiated by laser, the optical properties such as absorption and scattering coefficients are required. There have been various techniques for measuring these coefficients. One method requires tissue samples, often a slab of thin tissue, is invasive. On the other hand, non-invasive method usually measures back-scattered light from a subject with no physical intervent ions. Advantages and disvantages of using different methods are investigated. A careful attention should be made in order to select the best method for a given experimental condition since, even either for invasive or non-invasive method, accuracy is subject to governing models and sample preparations.

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Tissue and Immune Responses on Implanted Nanostructured Biomaterials

  • Khang, Dong-Woo;Kang, Sang-Soo;Nam, Tae-Hyun
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2009년도 춘계학술발표대회
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    • pp.47.1-47.1
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    • 2009
  • Nanostructured biomaterials have increased those potential for utilizing in many medical applications. In this study, benefit of nanotechnology for the response with biological targets will be described in terms of size, effective surface area and surface energy (physical aspect). Also, correlations between physical and biological interactions (greater protein adsorption on nano surface roughness) will be discussed for understanding biocompatibility of nanostructured biomaterials including carbon nanotube composites and nanostructured titanium surfaces. In the application parts, various major tissue cells, such as bone, cartilage, vascular and bladder cell responses will be discussed with suggested nanomaterials. Lastly, immune responses with macrophage (adhesion and several major cytokines) on nanostructured biomaterials will be described for evasive immune response.

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인체 유래 물질의 재산권성에 대한 의료법학적 고찰 (Medicolegal Study on Human Biological Material as Property)

  • 이웅희
    • 의료법학
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    • 제10권2호
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    • pp.455-492
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    • 2009
  • (Background) Recent biotechnological breakthroughs are shedding new lights on various ethical and legal issues about human biological material. Since Rudolph Virchow, a German pathologist, had founded the medical discipline of cellular pathology, issues centering around human biological materials began to draw attention. The issues involving human biological materials were revisited with more attention along with series concerns when the human genome map was finally completed. Recently, with researches on human genes and bioengineering reaping enormous commercial values in the form of material patent, such changes require a society to reassess the present and future status of human tissue within the legal system. This in turn gave rise to a heated debate over how to protect the rights of material donors: property rule vs. no property rule. (Debate and Cases) Property rule recognizes the donors' property rights on human biological materials. Thus, donors can claim real action if there were any bleach of informed consent or a donation contract. Donors can also claim damages to the responsible party when there is an infringement of property rights. Some even uphold the concept of material patents overtaking. From the viewpoint of no property rule, human biological materials are objects separated from donors. Thus, a recipient or a third party will be held liable if there were any infringement of donor's human rights. Human biological materials should not be commercially traded and a patent based on a human biological materials research does not belong to the donor of the tissues used during the course of research. In the US, two courts, Moore v. Regents of the University of California, and Greenberg v. Miami Children's Hospital Research Institute, Inc., have already decided that research participants retain no ownership of the biological specimens they contribute to medical research. Significantly, both Moore and Greenberg cases found that the researcher had parted with all ownership rights in the tissue samples when they donated them to the institutions, even though there was no provision in the informed consent forms stating either that the participants donated their tissue or waived their rights to ownership of the tissue. These rulings were led to huge controversy over property rights on human tissues. This research supports no property rule on the ground that it can protect the human dignity and prevent humans from objectification and commercialization. Human biological materials are already parted from human bodies and should be treated differently from the engineering and researches of those materials. Donors do not retain any ownership. (Suggestions) No property rule requires a legal breakthrough in the US in terms of donors' rights protection due to the absence of punitive damages provisions. The Donor rights issue on human biological material can be addressed through prospective legislation or tax policies, price control over patent products, and wider coverage of medical insurance. (Conclusions) Amid growing awareness over commercial values of human biological materials, no property rule should be adopted in order to protect human dignity but not without revamping legal provisions. The donors' rights issue in material patents requires prospective legislation based on current uncertainties. Also should be sought are solutions in the social context and all these discussions should be based on sound medical ethics of both medical staffs and researchers.

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