• Journal of Nutrition and Health
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• v.35 no.2
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• pp.192-200
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• 2002

Conjugated linoleic acid (CLA) is a collective term for positional and geometric isomers of octadecadienoic acid in which the double bonds are conjugated. CLA has anticancer activity in a variety of animal cancer models, and cis-9, trans-11 (c9t11) and trans-10, cis-12(t10c12) CLA are the most predominant isomers present in the synthetic preparations utilized in these animal studies. To compare the ability of c9t11, t10c12 and an isomeric mixture of CLA to inhibit TSU-Prl cell growth, cells were incubated in a serum-free medium with various concentrations of these fatty acids. The isomeric mixture inhibited cell growth in a dose-dependent manner (1-3 $\mu$M) with a 41 $\pm$ 1% inhibition observed at 3 $\mu$M concentration after 48 hours. T10c12 also inhibited cell proliferation in a dote-dependent manner, However, the efficacy and potency of this isomer was much greater than that of the isomeric mixture with a 49 $\pm$ 2% inhibition observed at 0.3 $\mu$M concentration after 48 hours. By contrast, c9t11 slightly increased cell proliferation. To determine whether the growth-inhibiting effect of CLA is related to the changes in production of insulin-like growth factors (IGF) and IGF-binding proteins (IGFBP) by these cells, serum-free conditioned media were collected. Immunoblot analysis of conditioned media using a monoclonal anti-IGF-II antibody showed that both the isomeric mixture and t10c12 inhibited secretion of both mature 7,500 Mr and higher Mr forms of pro IGF-II, whereas c9t11 had no effect. Ligand blot analysis with 125I-IGF-II revealed the presence of two types of IGFBPs : 24,000 Mr IGFBP-4 and 30,000 Mr IGFBP-6. The production of IGFBP-4 slightly decreased at the highest concentrations of the isomeric mixture and t10c12. These results indicate that CLA inhibits human prostate cancer cell growth, an effect largely due to the action of t10c12. The growth inhibition may result, at least in part, from decreased production of IGF-II and IGFBP-4 by these cells.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.255-261
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• 2014

The generation amount of radioactive waste has been rapidly increased by increase of the usage of radioisotope source in medical field. Especially, the use of the radioactive source of I-131 with short half-life of 8.02 days used in treatment of thyroid has been increased, and all of the wastes concerned have been disposed by means of the self-disposal method. IAEA proposed criteria for clearance level of waste which depends on the individual (10 ${\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). In this study, various radioactive wastes in medical fields are collected and measured for establishing the disposal methods and procedures of radioactive wastes. In addition, comparison evaluation of decay storage period between the half-life which was calculated by attenuation curve based on real measurement and analytical half-life is considered. With comparing the theoretical half-life and the effective half life(7.72 days) which was based on the decay equation of measured data, it is resulted in the theoretical half-life is longer than effective half-life. The storage period of radioactive waste for self-disposal may be curtailed. The result of this study will be proposed as ISO standard.

• Progress in Medical Physics
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• v.25 no.1
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• pp.8-14
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• 2014

The amounts of radioactive wastes to be disposed in the medical institute have been increased due to development of radiation diagnosis and therapy rapidly. They are produced mostly by the very short lived radioisotopes such as $^{18}F$ used in PET/CT, $^{99m}Tc$, $^{123}I$, $^{125}I$ and $^{201}Tl$, etc. IAEA proposed a criteria for the clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). Radioactive wastes of $^{18}F$, $^{99m}Tc$, $^{123}I$, $^{125}I$ and $^{201}TI$ in the several types of container like Marinelli beaker, vial and plastic, were collected to measure the concentration of the waste of each nuclide in accordance with IAEA criteria. The measurement method and procedure of determining specific activity of the wastes using gamma emitters like MCA, gamma counter and beta emitters were developed. For the efficiency calibration of the detectors, CRM (certified reference material) which has the same dimension and shape was provided by Korea Research Institute of Standards and Science (KRISS). Correction factor of the radioactivity decay was calculated based on the measurement results, and the consideration of mutual relation with theoretical equation. The result of this study will be proposed as ISO standard.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1126-1133
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• 2002

Conjugated linoleic acid (CLA) is a collective term for a class of positional and geometric conjugated dienoic isomers of linoleic acid (LA) and has anti-cancer activity in experimental animals. We have previously observed that an isomeric mixture of CLA and trans-10,cis-12 (t10c12) inhibited cell growth in a dose-dependent manner whereas LA and cis-9,trans-11 (c9t11) had no effect. The present study examined whether the CLA mixture and t10c12 induce apoptotic cell death. TSU-Prl cells were incubated for three days in serum-free medium in the absence or presence of individual fatty acids, and the DNA fragmentation assay was performed. Cells treated with the CLA mixture or t10c12 produced a distinct oligonucleosomal ladder with different sizes of DNA fragments, a typical characteristic of cells undergoing apoptosis. By contrast, LA and c9t11 had no effect. Western immunoblot analysis of total lysates revealed that t10c12 reduced anti-apoptotic, 26 kDa, Bcl-2 protein levels by 49$\pm$8% compared with controls, whereas this CLA isomer did not alter pro-apoptotic,21 kDa, Bax protein levels. These results suggest that growth inhibitory effect of the t10c12 CLA isomer may, at least in part, be attributed to Increased apoptotic death in TSU-Prl cells.

• The Korean Society of Law and Medicine
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• v.23 no.2
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• pp.97-118
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• 2022

The use of diagnostic radiation in medical institutions is rapidly increasing. Accordingly, the collective effective dose is on the rise every year. Therefore, it is necessary to reduce the radiation exposure of the person undergoing the radiation examination as low as reasonably achievable. And we must establish a legal system to perform the safe management of radiation for diagnosis efficiently. In this way, I went over the problems of the Act and Subordinate Statutes regarding radiation safety management for diagnosis. As a result, the main contents are as follows. First, in the 「Medical Service Act」, there is no basis for the Safety Inspection Institute of Radiation and Radiation Exposure Measuring Institutes. And there are no provisions concerning delegation of administrative disposition. Therefore, it is necessary to secure legal justification by providing the basis for the Safety Inspection Institute of Radiation along with Radiation Exposure Measuring Institutes and the basis for administrative dispositions against these institutions in the 「Medical Service Act」. Second, the 「Rules on the Installation and Operation of Special Medical Equipment 」 should be integrated with the 「Rules on the Safety Management of Radiation Generators for Diagnostics」 to unify administrative procedures such as reporting for radiation special medical equipment for diagnosis. Third, in the case of violating the diagnostic radiation safety management standards in the 「Rules on the Safety Management of Radiation Generators for Diagnostics」, it is necessary to supplement the insufficient sanctions such as administrative disposition. Fourth, regulating diagnostic radiation and therapeutic radiation used in medical institutions with the dual legal system of the 「Medical Act」 and the 「Nuclear Safety Act」 is not efficient in the safety management of diagnostic radiation. Therefore, it is necessary to uniformly regulate diagnostic radiation and all medical radiation, including therapeutic radiation and nuclear medicine, in the 「Medical Service Act」 system.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.633-638
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• 2017

The amount of radioactive waste has been rapidly increased with development of radiation treatment in medical field. Recently, it has been a common practice to use I-131 for thyroid cancer, F-18 for PET/CT and Tc-99m for diagnosis of nuclear medicine. All the wastes concerned have been disposed of by means of the self-disposal method, for example incineration, after storage enough to decay less than clearance level. IAEA proposed criteria for clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). In this study, specific radioactivity of radioactive waste contaminated with Re-186 was measured to confirm whether it meets the clearance level. Re-186 has long half life of 3.8 days relatively and emits beta and gamma radiation, therefore it can be applied in treatment and imaging purposes. The specific radioactivity of contaminated gloves weared by radiation workers was measured by MCA(Multi-channel Analyzer) which was calibrated by reference materials in accordance with the measuring procedure. As a result, comparison evaluation of decay storage period between the half-life which was calculated by attenuation curve based on real measurement and physical half-life was considered, and it is showed that the physical half-life is longer than induced half-life. Therefore, the storage period of radioactive waste for self-disposal may be curtailed in case of application of induced half-life. The result of this study will be proposed as ISO standard.