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Ren T, Byun SH. High-rate Gamma Spectrometry Using a LaBr3(Ce) Scintillator with a Fast Pulse Shaping. Health Phys 2024; 126:268-271. [PMID: 38526244 DOI: 10.1097/hp.0000000000001785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
ABSTRACT The performance of a LaBr3(Ce) gamma spectrometer at high count rates was investigated up to an input count rate of 1.3 Mcps. In order to make its pulse processing faster, a preamplifier provided by the detector manufacturer was eliminated, and the signal from the photomultiplier tube was fed directly to a digital pulse processing system. To accomplish both fast pulse processing and good energy resolution, the pulse-shaping parameters were optimized at a low count rate of 1.5 kcps, and then measurements were carried out at various count rates. Input count rates ranging from 1.5 kcps to 21 kcps were produced using a set of 137Cs resin sources, while higher rates between 45 kcps and 1.3 Mcps were produced using a 1.2-GBq 137Cs source. The spectrometer showed an excellent performance for the input rate up to 150 kcps, while the dead time increased rapidly for the input rates above 150 kcps. The system dead time has been improved greatly by eliminating the preamplifier.
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Sun R, Atanackovic J, Hanu AR, Cheng X, Byun SH. Optimization and characterization of a coincidence beta-ray spectrometer. Appl Radiat Isot 2024; 204:111144. [PMID: 38104472 DOI: 10.1016/j.apradiso.2023.111144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 11/22/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
Aimed at beta spectrometry and dosimetry for mixed beta-gamma fields, a Si-plastic scintillator coincidence beta-ray spectrometer has been developed. The spectrometer collects pure beta-ray spectra by rejecting the gamma-ray detection events through coincidence. Both pulse height and arrival time of each detection event were recorded in list mode by a compact digital processing system. Spectral measurements were carried out using mixed beta-gamma fields from 90Sr/90Y and 137Cs sources for various beta and gamma count rates to evaluate the system performance. Coincidence beta spectra were collected for four fixed beta count rates (7.3-241 cps) from 90Sr/90Y while the gamma count rate from 137Cs was varied from 500 to 8000 cps. The coincidence beta spectrum was stable and unperturbed by the gamma detection events for most measurements while notable perturbation was observed in the low energy region when the beta to gamma count ratio is very low.
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Affiliation(s)
- Ruoyu Sun
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4L8, Canada.
| | - Jovica Atanackovic
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4L8, Canada; Ontario Power Generation, Whitby, L1N 9E3, Canada
| | - Andrei R Hanu
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4L8, Canada; Bruce Power, Tiverton, N0G 2T0, Canada
| | - Xingzhi Cheng
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4L8, Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4L8, Canada
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Singh R, Byun SH. A comprehensive Monte Carlo simulation of the neutron response of multi-element microdosimetric detectors based on THick Gas Electron Multiplier. Radiat Prot Dosimetry 2023; 199:1958-1962. [PMID: 37819298 DOI: 10.1093/rpd/ncad013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 10/28/2022] [Accepted: 01/02/2023] [Indexed: 10/13/2023]
Abstract
We present comprehensive Monte Carlo simulations for the neutron response of the multi-element microdosimetric detector based on THick Gas Electron Multiplier (THGEM). Simulations were carried out using the MCNP6.2 code to calculate the deposited energy spectrum in the gaseous sensitive volumes for three different configurations, 7 × 3, 19 × 5, 37 × 7 that occupy a cylindrical volume of 5-cm diameter by 5-cm length. The energy response was computed from 10 keV to 2 MeV. The response variation was investigated between sensitive volumes as well as between layers. The simulated energy response showed a good agreement against the evaluated fluence-to-kerma conversion coefficients in the energy region 10-100 keV, whereas discrepancies were observed in the region above 250 keV. The angular response simulations showed a variation of less than 10%.
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Affiliation(s)
- R Singh
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - S H Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4L8, Canada
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Atanackovic J, Hanu AR, Byun SH. Eye lens dosimetry in Canadian CANDU nuclear power plants based on operational dosimetric quantities H p(10) and H p(0.07). Appl Radiat Isot 2021; 177:109902. [PMID: 34481317 DOI: 10.1016/j.apradiso.2021.109902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/29/2021] [Accepted: 08/13/2021] [Indexed: 11/18/2022]
Abstract
In this article, we present a methodology for performing eye lens dosimetry in CANDU nuclear power plants using an existing and highly accurate Harshaw 4-element TLD-700 dosemeter. This dosemeter, which has been specially designed for Ontario Power Generation (OPG) and Bruce Power (BP), measures the deep and shallow personal dose equivalent quantities Hp(10) and Hp(0.07), respectively. Using these measured personal dose equivalent quantities and applying a beta-ray strength scaling factor to the Hp(0.07) measurement in particular, we have developed an algorithm that can be used to calculate the dose to the lens of the eye in mixed beta-gamma fields. This scaling factor has been developed and is primarily based on results obtained from extensive collaborative study, performed by Ontario Power Generation (OPG), Bruce Power (BP) and McMaster University, through Candu Owners Group (COG) support (Bohra et al., 2021; Laranjeiro et al., 2020). Furthermore, scaling factor F, also includes effects of protective glass eyewear and results from Whole body dosimetry intercomparison exercises. The algorithm to calculate eye lens dose at CANDU power plants has been developed, based on this scaling factor and operational dosimetric quantities Hp(10) and Hp(0.07).
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Affiliation(s)
- J Atanackovic
- Ontario Power Generation, Whitby, ON, L1N 9E3, Canada; McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada.
| | - A R Hanu
- Bruce Power, Tiverton, ON, N0G 2T0, Canada; McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
| | - S H Byun
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
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Kim E, Cho MR, Byun SH, A Lim J, Chae S, Choi WK, Kim I, Kim J. Sympathetic predominance before tourniquet deflation is associated with a reduction in arterial blood pressure after tourniquet deflation during total knee arthroplasty. Physiol Res 2021; 70:401-412. [PMID: 33982581 DOI: 10.33549/physiolres.934639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
High dependency of arterial blood pressure (ABP) on enhanced sympathetic activity, which maintains vascular tone, leads to hypotension after hemodynamic insults that blunt the sympathetic activity. Therefore, we hypothesized that sympathovagal balance before tourniquet deflation (TD) determines the extent of a reduction in ABP after TD during total knee arthroplasty (TKA). Fifty-four hypertensive female patients undergoing TKA under spinal anesthesia were analyzed. The sympathovagal balance [low-to-high frequency ratio of heart rate variability (LF/HF)] before TD was defined as (LF/HF during 5 min before TD-preanesthetic LF/HF)/preanesthetic LF/HF (%). An increase in its value represents a shift in sympathovagal balance toward sympathetic predominance. The percent change in the mean ABP (MAP) after TD was defined as (minimum MAP during 10 min after TD-averaged MAP during 5 min before TD)/averaged MAP during 5 min before TD (%). Simple linear regression was performed to assess the correlation between the sympathovagal balance before TD and change in MAP after TD. The correlation was also assessed by multiple linear regression controlling for age, duration of tourniquet inflation, and spinal anesthesia-induced hypotension. Thirty-two minutes (on average) after tourniquet inflation, the MAP was decreased by 12.1 (-3.0 to 47.9) % [mean (range)] upon TD (P<0.001). The sympathovagal balance before TD was negatively proportional to the change in MAP after TD in both simple and multiple linear regression models (R2=0.323 and 0.340, P<0.001). A shift in sympathovagal balance toward sympathetic predominance before TD is associated with a decrease in ABP after TD.
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Affiliation(s)
- E Kim
- Department of Anesthesiology and Pain Medicine, Daegu Catholic University Medical Center, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea.
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Bohra F, Atanackovic J, Byun SH, Hanu AR, Laranjeiro A. Quantification of pure beta spectra in mixed beta gamma fields as part of eye lens dosimetry at CANDU power plants. Appl Radiat Isot 2021; 174:109746. [PMID: 33930726 DOI: 10.1016/j.apradiso.2021.109746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 11/26/2022]
Abstract
To address the issue of eye lens dosimetry in nuclear industry, we initiated the project to quantify the beta and gamma-ray source term in CANDU power plants and to convert this source term into dosimetric quantities of interest, such as eye lens dose and personal dose equivalents Hp(10), Hp(0.07). This way, the eye lens dose can be compared with dosimetric operational quantities to evaluate whether independent dosimetry is required for eye lens protection, or present dosimetry is adequate.
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Affiliation(s)
- F Bohra
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
| | - J Atanackovic
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada; Ontario Power Generation, Whitby, ON, L1N 9E3, Canada.
| | - S H Byun
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
| | - A R Hanu
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada; Bruce Power, Tiverton, ON, N0G 2T0, Canada
| | - A Laranjeiro
- McMaster University, Department of Physics and Astronomy, Hamilton, ON, L8S 4L8, Canada
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Fernando C, Byun SH, Shi X, Seymour CB, Mothersill CE. Isolation of the effects of alpha-related components from total effects of radium at low doses. Int J Radiat Biol 2021; 98:1168-1175. [PMID: 33332185 DOI: 10.1080/09553002.2020.1866226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE Radium is the most common source of alpha radiation exposure to humans and non-human species in the environment but the dosimetry is complicated by the decay chain which involves gamma exposure due to radon daughters. This paper seeks to determine the separate contributions of alpha and gamma doses to the total dose and total direct and non-targeted effect in a fish and a human cell line. MATERIALS AND METHODS This study aimed to isolate the effect of alpha particles following exposure to low doses of radium in cells, and their progeny which received no further exposure. This was initially done by comparing the survival values of a human keratinocyte cell line (HaCaT) and an embryonic Chinook salmon cell line (CHSE-214) exposed to gamma radiation, from survival of the same cell lines exposed to mixed alpha and gamma radiation through exposure to Ra-226 and its decay products. A Monte Carlo simulation was later performed to determine the contributions of radium decay products including radon daughters. RESULTS The human cell line showed increased radioresistance when exposed to low doses of alpha particles. In contrast the fish cell line, which demonstrated radioresistance to low dose gamma radiation, showed increased lethality when exposed to low doses of alpha particles. Significant and complex levels of non-targeted effects were induced in progeny of irradiated cells. The simulation showed that gamma and beta decay products did not contribute significant dose and the highest beta dose was below the threshold for inducing non-targeted effects. CONCLUSIONS The results confirm the need to consider the dose-response relationship when developing radiation weighting factors for low dose exposures, as well as the need to be aware of possible cell line and species differences.
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Affiliation(s)
- Chandula Fernando
- Radiation Sciences Graduate Program, McMaster University, Hamilton, Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, Canada
| | - Xiaopei Shi
- Department of Biology, McMaster University, Hamilton, Canada
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, Canada
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Laranjeiro AS, Bohra F, Byun SH, Atanackovic J, Hanu AR. CHARACTERIZATION OF A LANTHANUM BROMIDE DETECTOR FOR EYE LENS DOSIMETRY AT THE CANDU NUCLEAR POWER PLANTS BASED ON DIRECT MEASUREMENTS OF THE GAMMA-RAY SPECTRA. Radiat Prot Dosimetry 2020; 192:309-320. [PMID: 33320200 DOI: 10.1093/rpd/ncaa186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 09/27/2020] [Accepted: 10/18/2020] [Indexed: 06/12/2023]
Abstract
Gamma-ray spectra were measured using a LaBr$_{3}$(Ce) spectrometer during the outage periods, aiming at quantifying the gamma source term of radiation workers' exposure, at the CANDU nuclear power reactors, for the purposes of eye lens dosimetry. The spectra were measured inside the boiler rooms, of the Bruce Power and Ontario Power Generation (OPG) CANDU nuclear power plants, where workers are exposed to relatively high dose rates radiation fields during the maintenance work. Prior to measurements at the CANDU reactors, the pulse shaping parameters of the gamma spectrometer were optimised for high rates gamma fields, up to an input rates of 120 kcps, in order to accomplish a high output rate with a reasonable energy resolution. In parallel, the response of the LaBr$_{3}$(Ce) detector was characterized by experiments and Monte Carlo simulations. The gamma spectra measured at the CANDU reactors were reported in terms of the gamma-ray fluence rate spectrum. In all measured data, $^{60}$Co and $^{95}$Nb were main contributors of the gamma fields. The measured spectra have been used to calculate the dosimetric quantities of interest: personal dose equivalents H$_{p}$(10) and H$_{p}$(0.07) and eye lens absorbed dose.
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Affiliation(s)
- A S Laranjeiro
- Department of Physics and Astronomy, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - F Bohra
- Department of Physics and Astronomy, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - S H Byun
- Department of Physics and Astronomy, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
| | - J Atanackovic
- Department of Physics and Astronomy, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
- Ontario Power Generation, 1549 Victoria St E, Whitby, ON, L1N 9E3, Canada
| | - A R Hanu
- Department of Physics and Astronomy, McMaster University, 1280 Main St W, Hamilton, ON, L8S 4L8, Canada
- Bruce Power, 177 Tie Rd, Tiverton, ON, N0G 2T0, Canada
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Hancock S, Vo NTK, Goncharova RI, Seymour CB, Byun SH, Mothersill CE. One-Decade-Spanning transgenerational effects of historic radiation dose in wild populations of bank voles exposed to radioactive contamination following the chernobyl nuclear disaster. Environ Res 2020; 180:108816. [PMID: 31627157 DOI: 10.1016/j.envres.2019.108816] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
The concept of historic radiation doses associated with accidental radioactive releases and their role in leading to radiation-induced non-targeted effects on affected wild animals are currently being evaluated. Previous research studying Fukushima butterfly, Chernobyl bird and fruit fly populations shows that the effects are transgenerational, underlined by the principles of genomic instability, and varied from one species to another. To further expand on the responses of and their sensitivity in different taxonomically distinct groups, the present study sought to reconstruct historic radiation doses and delineate their effects on bank voles (Clethrionomys glareolus) found within a 400-km radius of the Chernobyl Nuclear Power Plant meltdown site. Historic dose reconstruction from the whole-body dose rates for the bank vole samples for their parental generation at the time of radioactive release was performed. Relationships between the historic doses and cytogenetic aberrations and embryonic lethality were examined via graphical presentations. Results suggest that genomic instability develops at the historic dose range of 20-51 mGy while a radioadaptive response develops at the historic dose range of 51-356 mGy. The Linear No-Threshold (LNT) relationship was absent at historic doses of lower than 356 mGy at all generations. However, LNT was apparent when the very high historic dose of 10.28 Gy in one sampling year was factored into the dose response curve for the bank vole generation 21-22. It is worth being reminded that natural mutation accumulation and other environmental stressors outside the realm of dose effects could contribute to the observed effects in a multiple-stressor environment. Nevertheless, the consistent development of genomic instability and radio-adaptive response across generations and sampling sites unearths the utmost fundamental radiobiological principle of transgenerational non-targeted effects. As a result, it calls for better attention and regulation from global governing bodies of environmental health protection.
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Affiliation(s)
- Samuel Hancock
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Nguyen T K Vo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Roza I Goncharova
- Institute of Genetics and Cytology, National Academy of Sciences, Minsk, Belarus
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
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Abstract
In a search to optimize neutron long counter design for overall efficiency and flat energy response, Monte Carlo simulations were carried out for a variety of detector design parameters using the Monte Carlo N-Particle Extended code. Based on the standard long counter design by McTaggart, moderator diameter, moderator back length, and longitudinal hole diameter were sequentially varied, and the sensitivity of each parameter to the long counter response was systematically analyzed. For each design, simulations were done in the neutron energy range of 1 keV to 10 MeV. From the simulation results, it turned out that out of the three moderator parameters, the moderator diameter is most sensitive for optimizing the long counter response. As the last design parameter, the effect of the central slow-neutron counter was investigated, which showed a significant difference in the response. The investigation of each design parameter gave clear insight on its effect on the long counter response and enabled one to determine the optimum condition.
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Affiliation(s)
- R J Park
- Radiation Sciences Graduate Program, McMaster University
| | - S H Byun
- Radiation Sciences Graduate Program, McMaster University
- Department of Physics and Astronomy, McMaster University
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Kim E, Choi DL, Jung JY, Byun SH, Kim JD, Jwa EK, Kim TY, Kim DH, Kim JH. Shift in Sympathovagal Balance Toward Parasympathetic Predominance Is Associated With Attenuation of Portal Hyperperfusion in Cirrhotic Recipients Undergoing Living Donor Liver Transplant. Transplant Proc 2019; 51:1511-1515. [PMID: 31155184 DOI: 10.1016/j.transproceed.2019.01.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/28/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND The autonomic innervation to a liver graft remains lost up to 1 year after liver transplant. Therefore, we investigated the effects of recipients' autonomic nervous activity on the extent of portal hyperperfusion of a partial liver graft in the absence of the autonomic innervation. METHODS A total of 31 cirrhotic recipients undergoing right lobe living donor liver transplant were analyzed. Following a 10-minute absence of surgical stimulation after hepatic artery and bile duct reconstruction, the electrocardiogram and blood pressure waveforms were recorded for 5 minutes. Low-frequency (LF) and high-frequency (HF) powers and their ratio (LF/HF) were calculated using fast Fourier transform from the electrocardiogram waveform. A decrease in LF/HF represents a shift in sympathovagal balance toward parasympathetic predominance. Then, portal venous (PVF) and hepatic arterial (HAF) blood flows were measured in mL/min per 100 g of liver weight using spectral Doppler ultrasonography. A decrease in their ratio (PVF/HAF) represents attenuation of portal hyperperfusion. RESULTS The medians of the PVF and HAF were 349 and 27 mL/min/100 g liver weight with interquartile ranges of 272 to 617 mL/min/100 g liver weight and 22 to 41 mL/min/100 g liver weight, respectively, yielding a median of the PVF/HAF of 13.7 (interquartile range, 8.5-21.3). The median of LF/HF was 0.67 (interquartile range, 0.16-1.45). With a reduction in LF/HF, PVF/HAF decreased according to an S-curve regression model between them (PVF/HAF=e2.743+-0.031LF/HF,adjustedR2=0.129,P=0.027). CONCLUSION A shift in sympathovagal balance toward parasympathetic predominance is associated with attenuation of portal hyperperfusion in a partial liver graft.
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Affiliation(s)
- E Kim
- Department of Anesthesiology and Pain Medicine, Hanyang University Medical Center, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - D L Choi
- Division of Hepatobiliary Pancreas Surgery and Abdominal Organ Transplantation, Department of Surgery, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - J Y Jung
- Department of Anesthesiology and Pain Medicine, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - S H Byun
- Department of Anesthesiology and Pain Medicine, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - J D Kim
- Division of Hepatobiliary Pancreas Surgery and Abdominal Organ Transplantation, Department of Surgery, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - E K Jwa
- Division of Hepatobiliary Pancreas Surgery and Abdominal Organ Transplantation, Department of Surgery, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - T Y Kim
- Division of Acute Care Surgery, Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - D H Kim
- Department of Anesthesiology and Pain Medicine, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea
| | - J H Kim
- Department of Anesthesiology and Pain Medicine, School of Medicine, Daegu Catholic University, Daegu, Republic of Korea.
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Hancock S, Vo NTK, Byun SH, Zainullin VG, Seymour CB, Mothersill C. Effects of historic radiation dose on the frequency of sex-linked recessive lethals in Drosophila populations following the Chernobyl nuclear accident. Environ Res 2019; 172:333-337. [PMID: 30825683 DOI: 10.1016/j.envres.2019.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
Contrary to the effects of high doses of radiation, the effects of low doses of radiation are still being investigated. Low doses and their non-targeted effects in particular are of special interest for researchers. The accident that occurred at the Chernobyl Nuclear Power Plant (NPP) gives researchers the opportunity to view these effects outside of a laboratory environment. For this paper, the relationship between low historic radiation doses and the persistent genetic damage observed in populations of fruit flies (Drosophila melanogaster) around the Chernobyl NPP over 3 years will be investigated. Data from Zainullin et al. (1992) on the frequency of sex-linked recessive lethals (SLRLs) in D. melanogaster around the Chernobyl NPP. To calculate the absorbed historic external dose, a method based on the Gaussian plume model was used to find the external dose from both plume shine and ground shine. The dose attributed to the ground shine dose made a greater contribution to the overall absorbed external historic radiation dose than the plume shine dose. For earlier generations of Drosophila living in the radioactive contaminated sites, the SLRL frequencies appeared to correlate with the dose in a linear no-threshold relationship. The later descendent generations appeared to have developed a radio-adaptive-like response. This work contributes to the understanding of historic dose effects on wildlife health following the accidental release of high mount of radioactive materials into the environment.
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Affiliation(s)
- Samuel Hancock
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Nguyen T K Vo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Vladimir G Zainullin
- Department of Radioecology, Institute of Biology of Komi Science Centre, Ural Division of the Russian Academy of Science, Syktyvkar, Russia
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Carmel Mothersill
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.
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Oh S, Jang JH, Kim HJ, Seo NS, Byun SH, Kim SW, Kim DS. Long-term Follow-up of Complicated Crown Fracture With Fragment Reattachment: Two Case Reports. Oper Dent 2019; 44:574-580. [PMID: 30702408 DOI: 10.2341/18-201-t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Two cases of complicated crown fracture of the maxillary incisors were restored using the fragment reattachment technique. Root canal treatment was performed, and the fractured fragment was bonded to the tooth structure using a dentin adhesive system and a flowable composite resin, followed by the insertion of a fiber post using dual-cured resin cement. Reattached fragments have shown reliable prognosis without inflammatory signs around bonded junctions after long-term follow-up.
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Hancock S, Vo NTK, Omar-Nazir L, Batlle JVI, Otaki JM, Hiyama A, Byun SH, Seymour CB, Mothersill C. Transgenerational effects of historic radiation dose in pale grass blue butterflies around Fukushima following the Fukushima Dai-ichi Nuclear Power Plant meltdown accident. Environ Res 2019; 168:230-240. [PMID: 30321736 DOI: 10.1016/j.envres.2018.09.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/27/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
Low dose radiation effects have been investigated in Chernobyl for many years but there is uncertainty about initial doses received by many animal species. However, the Fukushima Dai-ichi Nuclear Power Plant accident opens an opportunity to study the effects of the initial low historic dose on directly exposed species and their progeny during a time where the contaminating radionuclides are decaying. In this paper, it is proposed that historic acute exposure and its resulting non-targeted effects (NTEs) may be partially involved in the high mortality/abnormality rates seen across generations of pale grass blue butterflies (Zizeeria maha) around Fukushima. Data from Hiyama et al. (2012) on the morphological abnormality frequencies in Z. maha collected around Fukushima and their progeny were used in this paper. Two dose reconstruction methods based on the Gaussian plume model were used to determine the external absorbed dose to the first exposed generation from both ground shine and plume shine. One method involved the use of the dose rate recorded at the time of collection and only took Cs-137 into account. The other involved using release rates and atmospheric conditions to determine the doses and considered Cs-137 and Cs-134. The reconstructed doses were plotted against the mortality rates and abnormality frequencies across generations. The mortality rates of the progeny from irradiated progenitors increased linearly with the increasing historic radiation doses reconstructed using both Cs-137 and Cs-134 sources. Additionally, a higher level of morphological abnormalities was observed in progeny than in the progenitors. The mean abnormality frequencies also increased throughout generations. As these results are a sign of NTEs being involved, it can be suggested that increasing mutation levels across generations may result, in part, from NTEs induced by the initial low dose received by the first exposed generation. However, continual accumulation of mutations over generations in their natural contaminated habitats remains a likely contributor into the observed outcome.
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Affiliation(s)
- Samuel Hancock
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Nguyen T K Vo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Laila Omar-Nazir
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | | | - Joji M Otaki
- The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Senbaru, Nishihara, Okinawa 903-0123, Japan
| | - Atsuki Hiyama
- Laboratory of Conservation Ecology, Department of Integrated Science and Engineering for Sustainable Society, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Soo Hyun Byun
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Carmel Mothersill
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.
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15
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Darvish-Molla S, Prestwich WV, Byun SH. Development of an advanced two-dimensional microdosimetric detector based on THick Gas Electron Multipliers. Med Phys 2018; 45:1241-1254. [DOI: 10.1002/mp.12750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/24/2017] [Accepted: 12/09/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Sahar Darvish-Molla
- Department of Physics and Astronomy (Medical Physics); McMaster University; Hamilton ON Canada
- Radiation Sciences Graduate program; McMaster University; Hamilton ON Canada
| | - William V. Prestwich
- Department of Physics and Astronomy (Medical Physics); McMaster University; Hamilton ON Canada
- Radiation Sciences Graduate program; McMaster University; Hamilton ON Canada
| | - Soo Hyun Byun
- Department of Physics and Astronomy (Medical Physics); McMaster University; Hamilton ON Canada
- Radiation Sciences Graduate program; McMaster University; Hamilton ON Canada
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16
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Hanu AR, Barberiz J, Bonneville D, Byun SH, Chen L, Ciambella C, Dao E, Deshpande V, Garnett R, Hunter SD, Jhirad A, Johnston EM, Kordic M, Kurnell M, Lopera L, McFadden M, Melnichuk A, Nguyen J, Otto A, Scott R, Wagner DL, Wiendels M. NEUDOSE: A CubeSat Mission for Dosimetry of Charged Particles and Neutrons in Low-Earth Orbit. Radiat Res 2016; 187:42-49. [PMID: 28001909 DOI: 10.1667/rr14491.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
During space missions, astronauts are exposed to a stream of energetic and highly ionizing radiation particles that can suppress immune system function, increase cancer risks and even induce acute radiation syndrome if the exposure is large enough. As human exploration goals shift from missions in low-Earth orbit (LEO) to long-duration interplanetary missions, radiation protection remains one of the key technological issues that must be resolved. In this work, we introduce the NEUtron DOSimetry & Exploration (NEUDOSE) CubeSat mission, which will provide new measurements of dose and space radiation quality factors to improve the accuracy of cancer risk projections for current and future space missions. The primary objective of the NEUDOSE CubeSat is to map the in situ lineal energy spectra produced by charged particles and neutrons in LEO where most of the preparatory activities for future interplanetary missions are currently taking place. To perform these measurements, the NEUDOSE CubeSat is equipped with the Charged & Neutral Particle Tissue Equivalent Proportional Counter (CNP-TEPC), an advanced radiation monitoring instrument that uses active coincidence techniques to separate the interactions of charged particles and neutrons in real time. The NEUDOSE CubeSat, currently under development at McMaster University, provides a modern approach to test the CNP-TEPC instrument directly in the unique environment of outer space while simultaneously collecting new georeferenced lineal energy spectra of the radiation environment in LEO.
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Affiliation(s)
- A R Hanu
- a NASA Goddard Space Flight Center, Greenbelt, Maryland 20771
| | - J Barberiz
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - D Bonneville
- c Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - S H Byun
- d Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - L Chen
- c Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - C Ciambella
- f Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - E Dao
- d Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - V Deshpande
- e Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - R Garnett
- d Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - S D Hunter
- a NASA Goddard Space Flight Center, Greenbelt, Maryland 20771
| | - A Jhirad
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - E M Johnston
- d Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - M Kordic
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - M Kurnell
- c Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - L Lopera
- f Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - M McFadden
- d Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - A Melnichuk
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - J Nguyen
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - A Otto
- e Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - R Scott
- e Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - D L Wagner
- c Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - M Wiendels
- Department of bElectrical and Computer Engineering, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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Darvish-Molla S, Prestwich WV, Byun SH. COMPREHENSIVE RADIATION DOSE MEASUREMENTS AND MONTE CARLO SIMULATION FOR THE 7Li(p,n) ACCELERATOR NEUTRON FIELD. Radiat Prot Dosimetry 2016; 171:421-430. [PMID: 26464524 DOI: 10.1093/rpd/ncv428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 08/13/2015] [Accepted: 09/11/2015] [Indexed: 06/05/2023]
Abstract
In order to investigate the radiation dose dependence on the incident proton energy, neutron and gamma-ray doses were measured using a tissue-equivalent proportional counter in the proton energy range of 1.95-2.50 MeV for the McMaster 7Li(p,n) neutron facility. Microdosimetric spectra were collected, and absorbed doses were determined at various positions inside the irradiation cavity, along the lateral axis and outside the shield to find out the spatial distributions of neutron and gamma-ray doses for each proton energy. In parallel with the absorbed dose measurements, MCNP Monte Carlo simulations were carried out and neutron fluence spectra were computed at various positions, which enabled determination of the neutron weighting factors. It was found that neutrons make a substantially dominant contribution to the total equivalent dose for most proton energies and positions. The effective dose for a human subject increased from 0.058 to 1.306 μSv μA-1 min-1 with the increase of proton energy from 1.95 to 2.5 MeV. It is expected that the reported data will be useful for 7Li(p,n) accelerator neutron users.
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Affiliation(s)
- S Darvish-Molla
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - W V Prestwich
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - S H Byun
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada L8S 4K1
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18
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Mohseni HK, Cowan D, Chettle DR, Priest ND, Atanackovic J, Byun SH, Prestwich WV. In vivo neutron activation study of the short-term kinetic behaviour of sodium and chlorine in the human hand. Physiol Meas 2016; 37:N76-N83. [PMID: 27710928 DOI: 10.1088/0967-3334/37/11/n76] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The time-dependent behaviour of sodium and chlorine was studied as a spinoff from a study of aluminum in the hand of subjects suffering from Alzheimer's disease and a control group, involving 15 Alzheimer's and 16 control subjects with an age range of 63-89 years. This was achieved using the in vivo neutron activation analysis system developed at McMaster University for the non-invasive measurement of aluminum, where a subject's hand is placed in a beam of accelerator-based thermalized neutrons, which activates elements by neutron capture. Following irradiation, the subject's hand is placed in a detection system comprising 9 NaI(Tl) detectors arranged in a 4π geometry to measure activated elements. The redistribution half-lives of the activation products 24Na and 38Cl from the hand were determined after correction for the physical half-life, by means of sequential analysis of the residual activity in the hand. The kinetic behaviours of sodium and chlorine were best characterized by an exponential function corresponding to the rapidly exchangeable pool. The mean redistribution half-lives from the hand for sodium and chlorine in the control subjects were 40.5 ± 17.4 min and 24.2 ± 8.5 min, respectively. For Alzheimer's disease subjects the mean redistribution half-lives were 58.2 ± 36.1 min for sodium and 33.6 ± 16.7 min for chlorine. There was no significant difference in chlorine and sodium redistribution half-lives between the Alzheimer's disease and control group subjects. These results are promising, given that the irradiation and counting protocol were optimized for the aluminum study, rendering them suboptimal for analyzing other elements and their rate of change with time. Further improvements include optimizing the irradiation protocol, longer counting times, and measuring the activity in the un-irradiated hand in various time intervals following irradiation.
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Affiliation(s)
- H K Mohseni
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada
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19
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Mohseni HK, Cowan D, Chettle DR, Milić AP, Priest N, Matysiak W, Atanackovic J, Byun SH, Prestwich WV. A Pilot Study Measuring Aluminum in Bone in Alzheimer’s Disease and control Subjects Using in vivo Neutron Activation Analysis. J Alzheimers Dis 2016; 53:933-42. [DOI: 10.3233/jad-160194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Hedieh K. Mohseni
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada
| | - David Cowan
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - David R. Chettle
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada
| | | | - Nicholas Priest
- Canadian Nuclear Laboratories, Chalk River Laboratories, ON, Canada
| | - Witold Matysiak
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| | | | - Soo Hyun Byun
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada
| | - William V. Prestwich
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, ON, Canada
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20
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Mohseni HK, Matysiak W, Chettle DR, Byun SH, Priest N, Atanackovic J, Prestwich WV. Optimization of data analysis for the in vivo neutron activation analysis of aluminum in bone. Appl Radiat Isot 2016; 116:34-40. [PMID: 27474904 DOI: 10.1016/j.apradiso.2016.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/03/2016] [Accepted: 07/07/2016] [Indexed: 11/16/2022]
Abstract
An existing system at McMaster University has been used for the in vivo measurement of aluminum in human bone. Precise and detailed analysis approaches are necessary to determine the aluminum concentration because of the low levels of aluminum found in the bone and the challenges associated with its detection. Phantoms resembling the composition of the human hand with varying concentrations of aluminum were made for testing the system prior to the application to human studies. A spectral decomposition model and a photopeak fitting model involving the inverse-variance weighted mean and a time-dependent analysis were explored to analyze the results and determine the model with the best performance and lowest minimum detection limit. The results showed that the spectral decomposition and the photopeak fitting model with the inverse-variance weighted mean both provided better results compared to the other methods tested. The spectral decomposition method resulted in a marginally lower detection limit (5μg Al/g Ca) compared to the inverse-variance weighted mean (5.2μg Al/g Ca), rendering both equally applicable to human measurements.
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Affiliation(s)
- H K Mohseni
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Canada.
| | - W Matysiak
- University of Florida Proton Therapy Institute, Jacksonville, FL, USA
| | - D R Chettle
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Canada
| | - S H Byun
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Canada
| | - N Priest
- Canadian Nuclear Laboratories, Chalk River Laboratories, Ontario, Canada
| | | | - W V Prestwich
- Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, Canada
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21
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Tahir SNA, Chettle DR, Byun SH, Prestwich WV. Feasibility of measuring selenium in humans usingin vivoneutron activation analysis. Physiol Meas 2015; 36:2217-30. [DOI: 10.1088/0967-3334/36/11/2217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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22
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Kim SK, Chung JH, Park HJ, Kang SW, Lim DJ, Byun SH, Baek DG, Ko HY, Lew BL, Baik HH, Sim WY. Polymorphisms in the promoter regions of the CXCL1 and CXCL2 genes contribute to increased risk of alopecia areata in the Korean population. Genet Mol Res 2015; 14:9667-74. [PMID: 26345899 DOI: 10.4238/2015.august.14.29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Alopecia areata (AA) is a common disease, which causes hair loss in humans. AA has a genetically complex inheritance. This study investigated the possible correlations between single nucleotide polymorphisms (SNPs) in the promoter regions of the chemokine (C-X-C motif) ligand 1 (melanoma growth stimulating activity, alpha) (CXCL1) and chemokine (C-X-C motif) ligand 2 (CXCL2) genes and the development of AA in the Korean population. Two hundred and thirty-five AA patients and 240 control subjects were recruited. The specific SNPs occurring in the promoter regions of the CXCL1 and CXCL2 genes (rs3117604, -429C/T and rs3806792, -264T/C, respectively) were genotyped. All data obtained was evaluated using the SNPStats, SPSS 18.0, and the Haploview v.4.2 software platforms. The Odd's ratios (OR), 95% confidence intervals (CI), and P values were calculated using multiple logistic regression models. Analyses of the genetic sequences obtained revealed a significant correlation between the two SNPs and the development of AA (rs3117604, P = 0.0009 in co-dominant model 1, P = 0.01 in co-dominant model 2, P = 0.004 in the dominant model, P = 0.005 in the log-additive model, P = 0.012 in allele distribution; rs3806792, P = 0.036 in co-dominant model 2, P = 0.0046 in the log-additive model). The TT and CC haplotypes were also observed to show a significant association with increased risk of AA (TT haplotype, P = 0.0018; CC haplotype, P = 0.0349). Our data suggests that the CXCL1 and CXCL2 genes may be associated with AA susceptibility.
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Affiliation(s)
- S K Kim
- Kohwang Medical Research Institute, College of Medicine, Seoul, Republic of Korea
| | - J-H Chung
- Kohwang Medical Research Institute, College of Medicine, Seoul, Republic of Korea
| | - H J Park
- Kohwang Medical Research Institute, College of Medicine, Seoul, Republic of Korea
| | - S W Kang
- Kohwang Medical Research Institute, College of Medicine, Seoul, Republic of Korea
| | - D-J Lim
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul, Republic of Korea
| | - S H Byun
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul, Republic of Korea
| | - D G Baek
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul, Republic of Korea
| | - H Y Ko
- Department of Biochemistry and Molecular Biology, College of Medicine, Seoul, Republic of Korea
| | - B-L Lew
- Department of Dermatology, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
| | - H H Baik
- Department of Dermatology, Kyung Hee University, College of Medicine, Seoul, Republic of Korea
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Bhatia C, Byun SH, Chettle DR, Inskip MJ, Prestwich WV. A neutron activation technique for manganese measurements in humans. J Trace Elem Med Biol 2015; 31:204-8. [PMID: 25169978 DOI: 10.1016/j.jtemb.2014.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 07/15/2014] [Accepted: 07/28/2014] [Indexed: 11/21/2022]
Abstract
Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Studies show that Mn metabolism is similar to that of iron, therefore, increased Mn levels in humans could interfere with the absorption of dietary iron leading to anemia. Also, excess exposure to Mn dust, leads to nervous system disorders similar to Parkinson's disease. Higher exposure to Mn is essentially related to industrial pollution. Thus, there is a benefit in developing a clean non-invasive technique for monitoring such increased levels of Mn in order to understand the risk of disease and development of appropriate treatments. To this end, the feasibility of Mn measurements with their minimum detection limits (MDL) has been reported earlier from the McMaster group. This work presents improvement to Mn assessment using an upgraded system and optimized times of irradiation and counting for induced gamma activity of Mn. The technique utilizes the high proton current Tandetron accelerator producing neutrons via the (7)Li(p,n)(7)Be reaction at McMaster University and an array of nine NaI (Tl) detectors in a 4 π geometry for delayed counting of gamma rays. The neutron irradiation of a set of phantoms was performed with protocols having different proton energy, current and time of irradiation. The improved MDLs estimated using the upgraded set up and constrained timings are reported as 0.67 μgMn/gCa for 2.3 MeV protons and 0.71 μgMn/gCa for 2.0 MeV protons. These are a factor of about 2.3 times better than previous measurements done at McMaster University using the in vivo set-up. Also, because of lower dose-equivalent and a relatively close MDL, the combination of: 2.0 MeV; 300 μA; 3 min protocol is recommended as compared to 2.3 MeV; 400 μA; 45 s protocol for further measurements of Mn in vivo.
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Affiliation(s)
- C Bhatia
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada.
| | - S H Byun
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - D R Chettle
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - M J Inskip
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - W V Prestwich
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
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24
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Ahmad SB, McNeill FE, Byun SH, Prestwich WV, Mothersill C, Seymour C, Armstrong A, Fernandez C. Ultra-Violet Light Emission from HPV-G Cells Irradiated with Low Let Radiation From (90)Y; Consequences for Radiation Induced Bystander Effects. Dose Response 2013; 11:498-516. [PMID: 24298227 DOI: 10.2203/dose-response.12-048.ahmad] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
In this study, we aimed to establish the emission of UV photons when HPV-G cells and associated materials (such as the cell substrate and cell growth media) are exposed to low LET radiation. The potential role of UV photons in the secondary triggering of biological processes led us to hypothesize that the emission and absorption of photons at this wavelength explain some radiation induced "bystander effects" that have previously been thought to be chemically mediated. Cells were plated in Petri-dishes of two different sizes, having different thicknesses of polystyrene (PS) substrate, and were exposed to β-radiation from (90)Y produced by the McMaster Nuclear Reactor. UV measurements were performed using a single photon counting system employing an interference-type filter for selection of a narrow wavelength range, 340±5 nm, of photons. Exposure of the cell substrates (which were made of polystyrene) determined that UV photons were being emitted as a consequence of β particle irradiation of the Petri-dishes. For a tightly collimated β-particle beam exposure, we observed 167 photons in the detector per unit μCi in the shielded source for a 1.76 mm thick substrate and 158 photons/μCi for a 0.878 mm thick substrate. A unit μCi source activity was equivalent to an exposure to the substrate of 18 β-particles/cm(2) in this case. The presence of cells and medium in a Petri-dish was found to significantly increase (up to a maximum of 250%) the measured number of photons in a narrow band of wavelengths of 340±5 nm (i.e. UVA) as compared to the signal from an empty control Petri-dish. When coloured growth medium was added to the cells, it reduced the measured count rate, while the addition of transparent medium in equal volume increased the count rate, compared to cells alone. We attribute this to the fact that emission, scattering and absorption of light by cells and media are all variables in the experiment. Under collimated irradiation conditions, it was observed that increasing cell density in medium of fixed volume resulted in a decrease in the observed light output. This followed a roughly exponential decline. We suggest that this may be due to increased scattering at the cell boundary and absorption of the UV in the cells. We conclude that we have measured UVA emitted by cells, cell medium and cell substrates as a consequence of their irradiation by low LET β-particle radiation. We suggest that these secondary UV photons could lead to effects in non-targetted cells. Some effects that had previously been attributed to a chemically mediated "bystander effect" may in fact be due to secondary UV emission. Some radiation bystander effect studies may require re-interpretation as this phenomenon of UV emission is further investigated.
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Affiliation(s)
- Syed Bilal Ahmad
- Medical Physics and Applied Radiation Sciences, McMaster University; Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences
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25
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Chamberlain M, Gräfe JL, Byun SH, Chettle DR, Egden LM, Orchard GM, Webber CE, McNeill FE. The feasibility ofin vivoquantification of bone-fluorine in humans by delayed neutron activation analysis: a pilot study. Physiol Meas 2012; 33:243-57. [DOI: 10.1088/0967-3334/33/2/243] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Liu Z, Prestwich WV, Stewart RD, Byun SH, Mothersill CE, McNeill FE, Seymour CB. Effective Target Size for the Induction of Bystander Effects in Medium Transfer Experiments. Radiat Res 2007; 168:627-30. [DOI: 10.1667/rr1014.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 06/27/2007] [Indexed: 11/03/2022]
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27
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Byun SH, Pejović-Milić A, McMaster S, Matysiak W, Liu Z, Watters LM, Prestwich WV, McNeill FE, Chettle DR. Dosimetric characterization of the irradiation cavity for accelerator-basedin vivoneutron activation analysis. Phys Med Biol 2007; 52:1693-703. [PMID: 17455391 DOI: 10.1088/0031-9155/52/6/010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A neutron irradiation cavity for in vivo activation analysis has been characterized to estimate its dosimetric specifications. The cavity is defined to confine irradiation to the hand and modifies the neutron spectrum produced by a low energy accelerator neutron source to optimize activation per dose. Neutron and gamma-ray dose rates were measured with the microdosimetric technique using a tissue-equivalent proportional counter at the hand irradiation site and inside the hand access hole. For the outside of the cavity, a spherical neutron dose equivalent meter and a Farmer dosemeter were employed instead due to the low intensity of the radiation field. The maximum dose equivalent rate at the outside of the cavity was 2.94 microSv/100 microA min, which is lower by a factor of 1/2260 than the dose rate at the hand irradiation position. The local dose contributions from a hand, an arm and the rest of a body to the effective dose rate were estimated to be 1.73, 0.782 and 2.94 microSv/100 microA min, respectively. For the standard irradiation protocol of the in vivo hand activation, 300 microA min, an effective dose of 16.3 microSv would be delivered.
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Affiliation(s)
- S H Byun
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Liu Z, Mothersill CE, McNeill FE, Lyng FM, Byun SH, Seymour CB, Prestwich WV. A Dose Threshold for a Medium Transfer Bystander Effect for a Human Skin Cell Line. Radiat Res 2006; 166:19-23. [PMID: 16808607 DOI: 10.1667/rr3580.1] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The existence of radiation-induced bystander effects mediated by diffusible factors is now accepted, but the mechanisms and precise behavior at low doses remain unclear. We exposed cells to gamma-ray doses in the range 0.04 mGy-5 Gy, harvested the culture medium, and transferred it to unirradiated reporter cells. Calcium fluxes and clonogenic survival were measured in the recipients. We show evidence for a dose threshold around 2 mGy for the human skin cell line used with a suggestion of increased survival below that dose. Similar experiments using direct gamma irradiation showed no reduction in survival until the dose exceeded 7 mGy. Preliminary data for neutrons where the gamma-ray dose was kept below the bystander threshold do not show a significant bystander effect in the dose range 1-33 mGy. A lack of a bystander response with neutrons occurred at around 1 Gy, where significant cell killing from direct irradiation was observed. The result may have implications for understanding the role of bystander effects at low doses.
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Affiliation(s)
- Zhengfeng Liu
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada L8S 4K1.
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Kim HS, Byun SH, Lee BM. Effects of chemical carcinogens and physicochemical factors on the UV spectrophotometric determination of DNA. J Toxicol Environ Health A 2005; 68:2081-95. [PMID: 16326425 DOI: 10.1080/15287390500182503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The ultraviolet (UV) absorbance ratio of 260/280 nm has been used as an indicator of DNA purity. However, the A260/A280 ratio may be beyond the normal range (1.8-1.9) due to physicochemical alterations produced by pH and temperature, and carcinogenic chemical modification. When the pH of the DNA solution buffer increased from 3 to 11, the A260/A280 ratio changed significantly from 1.5 to 2.2 in mixtures of DNA bases [A:T:C:G = 28.5:28.5: 21.5:21.5, i.e., (A + T)/(all four bases) = 57%, expressed as mole percent], of deoxyribonucleosides (adenosine:thymidine:cytidine:guanosine= 28.5:28.5:21.5:21.5, as mole percent), or of deoxyribonucleotides (dAMP:dTMP:dGMP:dCMP = 28.5:28.5:21.5:21.5, as mole percent) examined. The A260/A280 ratio increased with RNA contamination and exceeded 1.9 when RNA concentration was >30%, as mole percent. In contrast, the A260/A280 ratio was linearly reduced by increasing the protein concentration. Phenol (>0.02%) contamination also reduced the A260/A280 ratio to below 1.8. Benzo[a]pyrene diol epoxide (BPDE), a reactive carcinogen metabolite of benzo[a]pyrene (BaP), decreased the A260/A280 ratio correlated with the degree to which it modified the DNA. These results suggest that the UV A260/A280 ratio is significantly affected by pH and the presence of contaminating species of macromolecules and chemicals.
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Affiliation(s)
- Hyung Sik Kim
- Laboratory of Molecular Toxicology, College of Pharmacy, Pusan National University, Jangjun-dong, Gumjung-ku, Pusan, South Korea
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Grinyer J, Byun SH, Chettle DR. In vivo prompt gamma neutron activation analysis of cadmium in the kidney and liver. Appl Radiat Isot 2005; 63:475-9. [PMID: 15994089 DOI: 10.1016/j.apradiso.2005.05.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 03/28/2005] [Accepted: 05/24/2005] [Indexed: 11/27/2022]
Abstract
An existing McMaster University in vivo prompt gamma neutron activation analysis system has been improved in order to reduce the cadmium detection limit in the kidney and liver. The detection limit for the kidney was found to be 1.7 mg, a greater than factor of 2 improvement over the previous results obtained at McMaster. The liver detection limit was determined to be 3.3 ppm. The corresponding skin dose for these measurements was only 0.5 mSv. The effect of kidney position on the detection limit also was examined. Figures of merit were calculated in order to compare the performance of the current system to others.
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Affiliation(s)
- J Grinyer
- Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., Canada.
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Pejović-Milić A, Byun SH, Comsa DC, McNeill FE, Prestwich WV, Chettle DR. In vivo measurement of bone aluminium: Recent developments. J Inorg Biochem 2005; 99:1899-903. [PMID: 16043224 DOI: 10.1016/j.jinorgbio.2005.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 06/09/2005] [Accepted: 06/09/2005] [Indexed: 10/25/2022]
Abstract
A biomarker of aluminium accumulation in the human body can play a valuable role in determining health effects of chronic aluminium exposure, complementing other human and environmental monitoring data. In vivo neutron activation provides such a non-invasive biomarker. To date, the best in vivo neutron activation system used thermalised neutrons from a nuclear reactor at Brookhaven National Laboratory, which suffered only slightly from interference from other elements, primarily phosphorus, and from the disadvantage of restricted accessibility. At McMaster, we use a nuclear reaction on an accelerator to select neutron energy, which eliminates the interferences. Spectral decomposition analysis improved sensitivity. A new 4pi detection system also enhanced sensitivity. Together these improvements yield a minimum detection limit of 0.24 mgAl in a hand, slightly better than at Brookhaven and equivalent to "normal" levels. Further improvements should result from a new irradiation cavity and from using a higher proton current on the accelerator to shorten irradiation times. The system is now ready for pilot human studies.
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Comsa DC, Prestwich WV, McNeill FE, Byun SH. Application of spectral decomposition analysis to in vivo quantification of aluminum by neutron activation analysis. Appl Radiat Isot 2004; 61:1353-60. [PMID: 15388133 DOI: 10.1016/j.apradiso.2004.03.062] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Revised: 10/28/2003] [Accepted: 03/15/2004] [Indexed: 10/26/2022]
Abstract
The toxic effects of aluminum are cumulative and result in painful forms of renal osteodystrophy, most notably adynamic bone disease and osteomalacia, but also other forms of disease. The Trace Element Group at McMaster University has developed an accelerator-based in vivo procedure for detecting aluminum body burden by neutron activation analysis (NAA). Further refining of the method was necessary for increasing its sensitivity. In this context, the present study proposes an improved algorithm for data analysis, based on spectral decomposition. A new minimum detectable limit (MDL) of (0.7+/-0.1)mg Al was reached for a local dose of (20+/-1)mSv. The study also addresses the feasibility of a new data acquisition technique, the electronic rejection of the coincident events detected by a NaI(Tl) system. It is expected that the application of this technique, together with spectral decomposition analysis, would provide an acceptable MDL for the method to be valuable in a clinical setting.
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Affiliation(s)
- D C Comsa
- Medical Physics and Applied Radiation Sciences Unit, McMaster University, 1280 Main St. W Hamilton, Ont., Canada, L8S 4K1.
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Sun GM, Kim IJ, Byun SH, Choi H, Kang C. Measurement of the Prompt k 0-factors for the Strong Non-1/v Absorbers relative to Cl. J NUCL SCI TECHNOL 2002. [DOI: 10.1080/00223131.2002.10875191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Lim K, Song HJ, Byun SH, Yun KA, Son MY, Park JI, Kweon GR, Yoon WH, Hwang BD. TATA element-binding protein is important to epidermal growth factor-dependent induction of H2B histone gene expression in primary hepatocytes from rat. Biochem Mol Biol Int 1998; 45:575-82. [PMID: 9679659 DOI: 10.1080/15216549800202972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Epidermal growth factor (EGF) is a potent mitogen for rat hepatocytes and mammalian histone synthesis is functionally and temporally coupled to DNA replication. To gain an insight on the role of EGF in the regulation of H2B histone gene expression in primary hepatocyte cultures, the binding patterns of nuclear proteins to various elements in the H2B histone gene upstream region have been investigated. EGF induced H2B histone mRNA with maximal stimulation reached at 36 hours. The induction of H2B histone mRNA was dependent on the concentration of EGF and almost reduced by actinomycin-D pretreatment. In DNase I footprinting analysis, one nuclear factor (TATA element-binding protein, TBP) bound at -20 bp (TATA element) in either the absence or presence of EGF. One DNA-protein complex was formed by DNA mobility shift assay when TATA element was incubated with nuclear extract prepared from EGF-free hepatocytes, and the amount of TBP was increased after EGF treatment. These results suggest that TBP may be correlated with transcriptional regulation of H2B histone gene by EGF in primary hepatocytes.
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Affiliation(s)
- K Lim
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon, Korea
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Abstract
Gastric adenocarcinoma is the most prevalent cancer in South Korea, and Helicobacter pylori (H. pylori) infection is also common. This study was performed to examine the association between H. pylori infection and gastric cancer, taking into account various other factors. To investigate the association between gastric adenocarcinoma and H. pylori infection, determined by urease-positive reaction in the CLO test, a total of 175 paired specimens (175 tumor and 175 tissues adjacent to tumor) of stomach cancer patients and a total of 113 control specimens were obtained. The positive H. pylori infection rates were 78.9% (138/175) among the patients in specimens of tumor or tissues adjacent to the tumor and 41.6% (47/113) among controls in the CLO test. A positive correlation between H. pylori infection and gastric cancer was observed (age-adjusted odds ratio, 7.0; MH chi2=34.5 with P<0.0005). These data suggest that stomach cancer patients in Korea have high infection rates of H. pylori regardless of site specificity, and this infection might be causally associated with stomach cancer.
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Affiliation(s)
- B M Lee
- Division of Toxicology, College of Pharmacy, Sung Kyun Kwan University, Suwon, Korea
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Abstract
The myocyte enhancer factor 2 (MEF2) gene family, which belongs to the MADS [MCM1, agamous, deficiens, serum response factor (SRF)] superfamily, is thought to play an important role in differentiation of myocytes, including cardiomyocytes. To better understand the mouse Mef2 gene family, the mouse Mef2b gene, which was found to be expressed in undifferentiated embryonal cells, was characterized. The Mef2b gene was found to be more than 30 kb in length, consisting of 11 exons. Eight exons correspond to coding regions and the remaining 3 exons for the 5' part are alternatively used. Two internal exons are subject to alternative splicing, resulting in production of four subtypes of mouse MEF2B peptides. Fluorescence in situ hybridization (FISH) and inter-specific backcross analysis identified the Mef2b gene locus. Mef2b gene was expressed in heart or skeletal muscle of early mouse embryo, but not in those of adult mouse. Functionally, mouse MEF2B did not exhibit DNA binding with the MEF2 consensus element in vitro, but did cause transcriptional activation of the MEF2 element, although it was less effective than human MEF2B. Based on these results, mouse MEF2B seems to have a unique character, distinct from other MEF2 family members.
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Affiliation(s)
- T Morisaki
- Department of Bioscience, National Cardiovascular Center Research Institute, Suita, Osaka.
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Terai Y, Fujii I, Byun SH, Nakajima O, Hakamatsuka T, Ebizuka Y, Sankawa U. Cloning of chalcone-flavanone isomerase cDNA from Pueraria lobata and its overexpression in Escherichia coli. Protein Expr Purif 1996; 8:183-90. [PMID: 8812858 DOI: 10.1006/prep.1996.0091] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chalcone-flavanone isomerase (CHI) cDNA was isolated from Pueraria lobata by combination of cDNA library screening using Phaseolus vulgaris CHI cDNA as a probe and polymerase chain reaction techniques. Analysis of nucleotide sequence of the cloned cDNA revealed a 675-bp open reading frame encoding a 225-amino-acid polypeptide with a molecular weight of 23,803 Da. The CHI cDNA coding region was cloned into pET-3d expression vector and successfully overexpressed in Escherichia coli cells as active CHI enzyme. The recombinant CHI was then purified to apparent homogeneity by DEAE-cellulose column chromatography. Replacement of Cys-119 with Ala was carried out by site-directed mutagenesis and the result that the mutant CHI showed CHI enzyme activity confirmed that Cys-119 is not involved in the CHI catalytic active site.
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Affiliation(s)
- Y Terai
- Faculty of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113, Japan
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Lim K, Yoon SJ, Lee MS, Byun SH, Kweon GR, Kwak ST, Hwang BD. Glucocorticoid regulation of androgen binding protein expression in primary Sertoli cell cultures from rats. Biochem Biophys Res Commun 1996; 218:490-4. [PMID: 8561783 DOI: 10.1006/bbrc.1996.0087] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glucocorticoids are known to inhibit testicular function, and its receptor is also localized in the Sertoli cells. To evaluate possible role of glucocorticoid in Sertoli cells, the effects of dexamethasone on the expression of androgen binding protein (ABP) have been investigated in primary Sertoli cell cultures. Dexamethasone increased ABP mRNA levels, with maximal stimulation reached at 36 hr. The induction of ABP mRNA was dependent on the low concentration (10(-8) and 10(-7) M) of dexamethasone but gradually reduced in the cells treated with high concentration (10(-6) and 10(-5) M). Dexamethasone-induced ABP mRNA level was no change in the cells after addition of cycloheximide but almost reduced by actinomycin-D pretreatment. Steady-state levels of ABP mRNA gradually increased in the Sertoli cells prepared from 14- and 21-days of age corresponding to rat puberty, and ABP mRNA was induced by dexamethasone. These results suggest that ABP gene is transcriptionally regulated by dexamethasone in primary Sertoli cell cultures.
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Affiliation(s)
- K Lim
- Department of Biochemistry, School of Medicine, Chungnam National University, Daejeon, Korea
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Hidaka K, Morisaki T, Byun SH, Hashido K, Toyama K, Mukai T. The MEF2B homologue differentially expressed in mouse embryonal carcinoma cells. Biochem Biophys Res Commun 1995; 213:555-60. [PMID: 7646512 DOI: 10.1006/bbrc.1995.2167] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The MEF2 gene family encodes a MADS-box transcription factor which regulates expression of many muscle-specific genes. We examined the expression of the MEF2 genes in mouse embryonal carcinoma P19 cells before and after in vitro muscle differentiation induced by dimethyl sulfoxide (DMSO). At least three different MADS/MEF2 domains (MEF2A, 2B and 2D) were isolated from P19 cells with the MOPAC technique (mixed oligonucleotides primed amplification of cDNA). Although two of the MADS/MEF2 domain sequences were identical to those of human MEF2A and MEF2D, another domain sequence was similar but not identical to that of human MEF2B. While the transcription of MEF2A and MEF2D was up-regulated during differentiation of P19 cells, the MEF2B homologue was abundantly transcribed in undifferentiated P19, F9 and ES cells and down-regulated in adult heart, skeletal muscle or brain, suggesting that the murine MEF2B homologue might have a function distinct from other members of the MEF2 gene family in embryogenesis and development.
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Affiliation(s)
- K Hidaka
- Department of Bioscience, National Cardiovascular Center Research Institute, Osaka, Japan
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