김필한 교수

The ability to conduct high-resolution fluorescence imaging in internal organs of small animal models in situ and over time can make a significant impact in biomedical research. Toward this goal, we developed a real-time confocal and multiphoton endoscopic imaging system. Using 1-mm-diameter endoscopes based on gradient index lenses, we demonstrate video-rate multicolor multimodal imaging with cellular resolution in live mice.

Lacteals are lymphatic vessels located at the center of each intestinal villus and provide essential transport routes for lipids and other lipophilic molecules. However, it is unclear how absorbed molecules are transported through the lacteal. Here, we used reporter mice that express GFP under the control of the lymphatic-specific promoter Prox1 and a custom-built confocal microscope and performed intravital real-time visualization of the absorption and transport dynamics of fluorescence-tagged

Recognizing an individual and retrieving and updating the value information assigned to the individual are fundamental abilities for establishing social relationships. To understand the neural mechanisms underlying the association between social identity and reward value, we developed Go-NoGo social discrimination paradigms that required male subject mice to distinguish between familiar mice based on their individually unique characteristics and associate them with reward availability. We found

The number of circulating tumor cell (CTC) in the peripheral blood of cancer patients can be a valuable biomarker for cancer diagnosis and treatment monitoring. In this study, we implemented a custom-design video-rate confocal microscopy system in capable of direct visualization of fast flowing CTC at great saphenous vein (GSV) of a live animal model in vivo. Continuous acquisition of video-rate images at GSV revealed the highly dynamic time-dependent changes in the number of intravenously injec

Direct intravital imaging of an endothelial surface layer (ESL) in pulmonary microcirculation could be a valuable approach to investigate the role of a vascular endothelial barrier in various pathological conditions. Despite its importance as a marker of endothelial cell damage and impairment of the vascular system, <i>in vivo</i> visualization of ESL has remained a challenging technical issue. In this work, we implemented a pulmonary microcirculation imaging system integrated to a custom-design

Cerebral microinfarct increases the risk of dementia. But how microscopic cerebrovascular disruption affects the brain tissue in cellular-level are mostly unknown. Herein, with a longitudinal intravital imaging, we serially visualized in vivo dynamic cellular-level changes in astrocyte, pericyte and neuron as well as microvascular integrity after the induction of cerebral microinfarction for 1 month in mice. At day 2-3, it revealed a localized edema with acute astrocyte loss, neuronal death, imp

Bone marrow is a vital tissue that produces the majority of erythrocytes, thrombocytes, and immune cells. Bone marrow transplantation (BMT) has been widely performed in patients with blood disorders and cancers. However, the cellular-level behaviors of the transplanted bone marrow cells over wide-areas of the host bone marrow after the BMT are not fully understood yet. In this work, we performed a longitudinal wide-area cellular-level observation of the calvarial bone marrow after the BMT in viv

-infected skin wounds of mice and perform PDT for 15 min. InP QDs show excellent therapeutic and prophylactic efficacy in treating MDR bacterial infection. These findings show that InP QDs have great potential to serve as antibacterial agents for MDR bacterial infection treatment, as an effective and complementary alternative to conventional antibiotics.

Dental pulp is composed of nerves, blood vessels, and various types of cells and surrounded by a thick and hard enamel-dentin matrix. Due to its importance in the maintenance of tooth vitality, there have been intensive efforts to analyze the complex cellular-level organization of the dental pulp in teeth. Although conventional histologic analysis has provided microscopic images of the dental pulp, 3-dimensional (3D) cellular-level visualization of the whole dental pulp in an intact tooth has re

1%, 1hr). Some of the ITx was performed in mouse insulin 1 gene promoter-green fluorescent protein (MIP-GFP) transgenic mice and analyzed using an in vivo imaging system. After 14 days of ITx, 2-hr glucose levels on GTT in the RSV-treated group were significantly lower than those of other control groups. But the glucose status was not improved in No-ITx mice with RSV. At day 3, the percentage of Ki-67/insulin co-stained cells in islet graft was significantly increased in the RSV-ITx group. Immun

High endothelial venules (HEVs) effectively recruit circulating lymphocytes from the blood to lymph nodes. HEVs have endothelial cells (ECs) and perivascular sheaths consisting of fibroblastic reticular cells (FRCs). Yet, post-luminal lymphocyte migration steps are not well elucidated. Herein, we performed intravital imaging to investigate post-luminal T- and B-cell migration in popliteal lymph node, consisting of trans-EC migration, crawling in the perivascular channel (a narrow space between E

We demonstrate a novel approach for the measurement of pump/signal waves interaction in the Raman amplifier (RA), with the use of multiwave optical time-domain reflectometry. With the application of obtained pump-evolution profiles to algorithms based on effective length recalibration, the multichannel Raman gain can easily be predicted with excellent accuracy for the undepleted, distributed RA. As a further extension of this algorithm, an in situ semi-analytic Raman-gain design method is also d

We propose and demonstrate a novel optical supervisory system for long-haul wavelength-division-muitiplexing (WDM) transmission link including cascaded erbium-doped fiber amplifiers (EDFAs). By employing a modified optical time domain reflectometry technique with a wavelength selective bidirectional EDFA, it was possible to monitor the status of the WDM transmission link and EDFA at in-service states with negligible power penalty. Proof of the concept with a 2.5 Gb/s/spl times/eight-channel WDM