• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.715-717
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• 2016

Conventional drug carriers such as liposomes, nanoparticles, polymer micelles, polymeric conjugate and lipid microemulsion for cancer chemotherapy shield normal tissues from toxic drugs to treat cancer cells in tumors. However, inaccurate tumor targeting uncontrolled drug release from the carriers and unwanted accumulation in healthy sites can limit treatment efficacy with current conventional drug carriers with insufficient concentrations of drugs in the tumors and unexpected side effects as a result. In this research, we examined the use of sickle red blood cells as a new drug carrier with novel tumor targeting and controlled release properties. Sickle red blood cells show natural tumor preferential accumulation without any manipulation and controlled drug release is possible using a hemolysis method with photosensitizers.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.1-6
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• 2019

Human mesenchymal stem cells (hMSC) are multipotent stromal cells that have great potential to differentiate into a variety of cell types such as osteocytes, chondrocytes, and myocytes. Although there have been many studies on their clinical availability, little is known about how intracellular signals can be modulated by topographic features of the extracellular matrix (ECM). In this study, we investigated whether and how microwavy-patterned extracellular matrix (ECM) could affect the signaling activity of focal adhesion kinase (FAK), a key cellular adhesion protein. The fluorescence resonance energy transfer (FRET)-based FAK biosensor-transfected cells are incubated on microwavy-patterned surfaces and then platelet derived growth factor (PDGF) are treated to trigger FAK signals, followed by monitoring through live-cell FRET imaging in real time. As a result, we report that PDGF-induced FAK was highly activated in cells cultured on microwavy-patterned surface with L or M type, while inhibited by H type-patterned surface. In further studies, PDGF-induced FAK signals are regulated by functional support of actin filaments, microtubules, myosin-related proteins, suggesting that PDGF-induced FAK signals in hMSC upon microwavy surfaces are dependent on cytoskeleton (CSK)-actomyosin networks. Thus, our findings not only provide new insight on molecular mechanisms on how FAK signals can be regulated by distinct topographical cues of the ECM, but also may offer advantages in potential applications for regenerative medicine and tissue engineering.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.474-476
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• 2021

Glioblastoma is the most common brain malignancies arising from glial cells. Early diagnosis and treatment plan establishment are important, and cancer is diagnosed mainly through T1CE imaging through injection of a contrast agent. However, the risk of injection of gadolinium-based contrast agents is increasing recently. Region segmentation that marks cancer regions in medical images plays a key role in CAD systems, and deep neural network models for synthesizing new images are also being studied. In this study, we propose a model that simultaneously learns the generation of T1CE images and segmentation of cancer regions. The performance of the proposed model is evaluated using similarity measurements including mean square error and peak signal-to-noise ratio, and shows average result values of 21 and 39 dB.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.179-181
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• 2023

본 논문에서는 GAN 기반의 영상 생성 방법론을 이용해 delayed PET 영상을 생성하는 연구를 수행하였다. PET은 양전자를 방출하는 방사성 동위원소를 표지한 방사성의약품의 체내 분포를 시각화함으로서 암 세포 진단에 이용되는 의료영상 기법이다. 하지만 PET의 스캔 과정에서 방사성의약품이 체내에 분포하는 데에 걸리는 시간이 오래 걸린다는 문제점이 존재한다. 따라서 본 연구에서는 방사성의약품이 충분히 분포되지 않은 상태에서 얻은 PET 영상을 통해 목표로 하는 충분히 시간이 지난 후에 얻은 PET 영상을 생성하는 모델을 GAN (generative adversarial network)에 기반한 image-to-image translation(I2I)를 통해 수행했다. 특히, 생성 전후의 영상 간의 영상 쌍을 고려한 paired I2I인 Pix2pix와 이를 고려하지 않은 unpaired I2I인 CycleGAN 두 가지의 방법론을 비교하였다. 연구 결과, Pix2pix에 기반해 생성한 delayed PET 영상이 CycleGAN을 통해 생성한 영상에 비해 영상 품질이 좋음을 확인했으며, 또한 실제 획득한 ground-truth delayed PET 영상과의 유사도 또한 더 높음을 확인할 수 있었다. 결과적으로, 딥러닝에 기반해 early PET을 통해 delayed PET을 생성할 수 있었으며, paired I2I를 적용할 경우 보다 높은 성능을 기대할 수 있었다. 이를 통해 PET 영상 획득 과정에서 방사성의약품의 체내 분포에 소요되는 시간을 딥러닝 모델을 통해 줄여 PET 이미징 과정의 시간적 비용을 절감하는 데에 크게 기여할 수 있을 것으로 기대된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2395-2400
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• 2016

Conventional drug carriers such as liposomes, nanoparticles, polymer micelles, polymeric conjugate and lipid microemulsion for cancer chemotherapy shield normal tissues from toxic drugs to treat cancer cells in tumors. However, inaccurate tumor targeting uncontrolled drug release from the carriers and unwanted accumulation in healthy sites can limit treatment efficacy with current conventional drug carriers with insufficient concentrations of drugs in the tumors and unexpected side effects as a result. Sickle red blood cells show natural tumor preferential accumulation without any manipulation due to the adhesive interaction between molecular receptors on the membrane surface and counter-receptor on endothelial cells. In addition, structural changes of microvascular in tumor sites enhances polymerization of sickle red blood cells. In this research, we examined the use of sickle red blood cells as a new drug carrier with novel tumor targeting and controlled release properties to quantify its therapeutic effects.

• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1033-1052
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• 2021

Bladder cancer is a relatively common cancer type, with a high recurrence rate, that can be often encountered in the imaging study. Accurate diagnosis and staging have a significant impact on determining treatment and evaluating prognosis. Bladder cancer has been evaluated by transurethral resection of bladder tumor for clinical staging and treatment, but it is often understaged when compared with final pathologic result by radical cystectomy. If the location, size, presence of muscle invasion, lymph node metastasis, distant metastasis, and presence of upper urinary tract cancer can be accurately diagnosed and evaluated in an imaging study, it can be treated and managed more appropriately. For an accurate diagnosis, radiologists who evaluate the images must be aware of the characteristics of bladder cancer as well as its types, imaging techniques, and limitations of imaging studies. Recent developments in MRI with functional imaging have improved the quality of bladder imaging and the evaluation of cancer. In addition, the Vesical Imaging Reporting and Data System was published to objectively assess the possibility for muscle invasion of cancer. Radiologists need to know the types of bladder cancer treatment and how to evaluate the changes after treatment. In this article, the characteristics of bladder urothelial carcinoma, various imaging studies, and findings are reviewed.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.1-17
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• 2020

Three-dimensional microscopic approaches in histopathology display multiplex properties that present puzzling questions for specimens as related to their comprehensive volumetric information. This information includes spatial distribution of molecules, three-dimensional co-localization, structural formation and whole data set that cannot be determined by two-dimensional section slides due to the inevitable loss of spatial information. Advancement of optical instruments such as two-photon microscopy and high performance objectives with motorized correction collars have narrowed the gap between optical theories and the actual reality of deep tissue imaging. However, the benefits gained by a prolonged working distance, two-photon laser and optimized beam alignment are inevitably diminished because of the light scattering phenomenon that is deeply related to the refractive index mismatch between each cellular component and the surrounding medium. From the first approaches with simple crude refractive index matching techniques to the recent cutting-edge integrated tissue clearing methods, an achievement of transparency without morphological denaturation and eradication of natural and fixation-induced nonspecific autofluorescence out of real signal are key factors to determine the perfection of tissue clearing and the immunofluorescent staining for high contrast images. When performing integrated laboratory workflow of tissue for processing frozen and formalin-fixed tissues, clear lipid-exchanged acrylamide-hybridized rigid imaging/immunostaining/in situ hybridization-compatible tissue hydrogel (CLARITY), an equipment-based tissue clearing method, is compatible with routine procedures in a histopathology laboratory.