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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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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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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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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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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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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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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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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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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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15
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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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16
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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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17
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Aslam, Pejović-Milić A, McNeill FE, Byun SH, Prestwich WV, Chettle DR. In vivoassessment of magnesium status in human body using accelerator-based neutron activation measurement of hands: A pilot study. Med Phys 2008; 35:608-16. [DOI: 10.1118/1.2830383] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18
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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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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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20
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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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22
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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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23
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24
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25
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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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26
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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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27
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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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28
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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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29
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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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