• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.8 s.173
• /
• pp.57-63
• /
• 2005

Development of a locomotive mechanism fer the capsule type endoscopes will largely enhance the ability to diagnose disease of digestive organs. In connection with it, most of researches have focused on an installable locomotive mechanism in the capsule. In this paper, it is introduced that the movement of a capsule type endoscope in digestive organ can be manipulated by magnetic force produced outside human body. Since the magnetic force is provided by permanent magnets, no additional power supply to the capsule is required. Using a robotic manipulator for locating the external magnet, the capsule motion control system can cover the whole human digestive organs. This study is particularly concentrated on dither motion effect to improve the mobility of capsule type endoscope. It was experimentally found out that the friction coefficient between the capsule and digestive organ can be remarkably reduced by superposing yawing or rolling dither motion on the translatory motion. In this paper, the experimental results obtained with the direction, amplitude and frequency of sinusoidal dither motion changed is reported.

• Toxicological Research
• /
• v.31 no.2
• /
• pp.137-149
• /
• 2015

Human hepatocytes, with complete hepatic metabolizing enzymes, transporters and cofactors, represent the gold standard for in vitro evaluation of drug metabolism, drug-drug interactions, and hepatotoxicity. Successful cryopreservation of human hepatocytes enables this experimental system to be used routinely. The use of human hepatocytes to evaluate two major adverse drug properties: drug-drug interactions and hepatotoxicity, are summarized in this review. The application of human hepatocytes in metabolism-based drug-drug interaction includes metabolite profiling, pathway identification, P450 inhibition, P450 induction, and uptake and efflux transporter inhibition. The application of human hepatocytes in toxicity evaluation includes in vitro hepatotoxicity and metabolism-based drug toxicity determination. A novel system, the Integrated Discrete Multiple Organ Co-culture (IdMOC) which allows the evaluation of nonhepatic toxicity in the presence of hepatic metabolism, is described.

• Molecules and Cells
• /
• v.41 no.2
• /
• pp.83-92
• /
• 2018

The biological significance and deregulation of the Hippo pathway during organ growth and tumorigenesis have received a surge of interest in the past decade. The Hippo pathway core kinases, MST1/2 and LATS1/2, are tumor suppressors that inhibit the oncogenic nuclear function of YAP/TAZ and TEAD. In addition to earlier studies that highlight the role of Hippo pathway in organ size control, cell proliferation, and tumor development, recent evidence demonstrates its critical role in cancer stem cell biology, including EMT, drug resistance, and self-renewal. Here we provide a brief overview of the regulatory mechanisms of the Hippo pathway, its role in cancer stem cell biology, and promising therapeutic interventions.

• Journal of Chest Surgery
• /
• v.55 no.4
• /
• pp.319-324
• /
• 2022

Although organ transplants have become quite common, combined heart-lung transplantation (CHLTx) is unfamiliar at most institutions. While the remarkable rate of development in treatment options, such as drugs and mechanical circulatory support, have reduced the need for CHLTx, it remains the sole treatment option for a subset of patients with end-stage cardiopulmonary failure. For many cardiothoracic surgeons, CHLTx is not technically new or difficult, but it does pose challenges due to its low frequency and relative complexity. Thus, this review aims to describe the CHLTx technique in technical detail using the existing literature.

• BMB Reports
• /
• v.55 no.5
• /
• pp.213-219
• /
• 2022

The blood-brain barrier (BBB) is an interface between cerebral blood and the brain parenchyma. As a gate keeper, BBB regulates passage of nutrients and exogeneous compounds. Owing to this highly selective barrier, many drugs targeting brain diseases are not likely to pass through the BBB. Thus, a large amount of time and cost have been paid for the development of BBB targeted therapeutics. However, many drugs validated in in vitro models and animal models have failed in clinical trials primarily due to the lack of an appropriate BBB model. Human BBB has a unique cellular architecture. Different physiologies between human and animal BBB hinder the prediction of drug responses. Therefore, a more physiologically relevant alternative BBB model needs to be developed. In this review, we summarize major features of human BBB and current BBB models and describe organ-on-chip models for BBB modeling and their applications in neurological complications.

• Electronics and Telecommunications Trends
• /
• v.38 no.1
• /
• pp.46-54
• /
• 2023

The announcement of the US Environmental Protection Agency that it will stop conducting or funding experimental studies on mammals by 2035 should prioritize ongoing efforts to develop and use alternative toxicity screening methods to animal testing. Toxicity screening is likely to be further developed considering the combination of human-induced pluripotent-stem-cell-derived organ-on-a-chip and multielectrode array (MEA) technologies. We briefly review the current status of MEA technology and MEA-based neuropharmacological drug screening using various cellular model systems. Highlighting the coronavirus disease pandemic, we shortly comment on the importance of early prediction of toxicity by applying artificial intelligence to the development of rapid screening methods.

• Clinical and Experimental Reproductive Medicine
• /
• v.39 no.4
• /
• pp.144-152
• /
• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• BMB Reports
• /
• v.52 no.8
• /
• pp.526-531
• /
• 2019

The vertebrate body plan is accomplished by left-right asymmetric organ development and the heart is a representative asymmetric internal organ which jogs to the left-side. Kupffer's vesicle (KV) is a spherical left-right organizer during zebrafish embryogenesis and is derived from a cluster of dorsal forerunner cells (DFCs). Cadherin1 is required for collective migration of a DFC cluster and failure of DFC collective migration by Cadherin1 decrement causes KV malformation which results in defective heart laterality. Recently, loss of function mutation of A-kinase anchoring protein 12 (AKAP12) is reported as a high-risk gene in congenital heart disease patients. In this study, we demonstrated the role of $akap12{\beta}$ in asymmetric heart development. The $akap12{\beta}$, one of the akap12 isoforms, was expressed in DFCs which give rise to KV and $akap12{\beta}$-deficient zebrafish embryos showed defective heart laterality due to the fragmentation of DFC clusters which resulted in KV malformation. DFC-specific loss of $akap12{\beta}$ also led to defective heart laterality as a consequence of the failure of collective migration by cadherin1 reduction. Exogenous $akap12{\beta}$ mRNA not only restored the defective heart laterality but also increased cadherin1 expression in $akap12{\beta}$ morphant zebrafish embryos. Taken together, these findings provide the first experimental evidence that $akap12{\beta}$ regulates heart laterality via cadherin1.

• Journal of Radiation Protection and Research
• /
• v.26 no.3
• /
• pp.249-253
• /
• 2001

Neutron dose assessment in criticality accidents using Whole Body Counter (WBC) was proved to be an effective method as rapid neutron dose estimation at the JCO criticality accident in Tokai-mura. The 1.36MeV gamma-ray of $^{24}Na$ in a body can be detected easily by a germanium detector. The Minimum Detectable Activity (MDA) of $^{24}Na$ is approximately 50Bq for 10miniute measurement by the germanium-type whole body counter at JNC Tokai Works. Neutron energy spectra at the typical shielding conditions in criticality accidents were calculated and the conversion factor, whole body activity-to-organ mass weighted neutron absorbed dose, corresponding to each condition were determined. The conversion factor for uncollied fission spectrum is 7.7 $[(Bq^{24}Na/g^{23}Na)/mGy]$.

• Genomics & Informatics
• /
• v.17 no.3
• /
• pp.24.1-24.8
• /
• 2019

Early environmental exposure is recognized as a key factor for long-term health based on the Developmental Origins of Health and Disease hypothesis. It considers that early-life nutrition is now being recognized as a major contributor that may permanently program change of organ structure and function toward the development of diseases, in which epigenetic mechanisms are involved. Recent researches indicate early-life environmental factors modulate the microbiome development and the microbiome might be mediate diet-epigenetic interaction. This review aims to define which nutrients involve microbiome development during the critical window of susceptibility to disease, and how microbiome modulation regulates epigenetic changes and influences human health and future prevention strategies.