Dosimetry of cell-monolayers in multiwell plat

2009 ◽  
Vol 48 (03) ◽  
pp. 120-126 ◽  
Author(s):  
M. Andreeff ◽  
L. Oehme ◽  
J. Kotzerke ◽  
R. Freudenberg
Keyword(s):  
Dose Distribution ◽  
Absorbed Dose ◽  
High Energy ◽  
X Rays ◽  
Sphere Model ◽  
Cell Monolayers ◽  
Calculated Dose ◽  
The Mean ◽  
The Impact

Summary Aim: Irradiation of cells in-vitro with unsealed radionuclides is often carried out in cylindrical multi-well-plates. For calculation of the absorbed dose using the sphere model is common. This model assumes a spherical distribution of activity. However, by physical aspects a dose reduction in the peripheral area of the activity volume is expected and predicted especially for high-energy beta-emitting radionuclides. The impact on cellular dosimetry shall be depicted in this paper. Methods: The dose-distribution inside a multi-well-plate was calculated by convolving the dose distribution around a point source with a given activity. This was performed for the radionuclides I-131, Re-188 and Y-90 in wells of different sizes. For comparison the sphere dose was also calculated. Results: Depending on the beta-energy differences up to 40% between the mean calculated dose and the mean sphere dose were found, whereby calculated dose was always lower than the sphere model prediction. Furthermore a fall-off was calculated for the bottom-dose compared to dose in the centre. An analytical expression was revealed for the bottom-dose with respect to the filling level for three different wells. Conclusion: The shape of geometry and the influence on dose distribution must be considered especially at in-vitro exposure with low energy and short range beta-emitting radionuclides. There could be a great impact for exact dose estimation, which is especially necessary to know for comparison of different irradiation experiments (e.g. different radionuclides, various irradiation geometries or comparison with x-rays).

scholarly journals Track Structure Study for Energy Dependency of Electrons and X-rays on DNA Double-Strand Break Induction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yoshie Yachi ◽  
Yuji Yoshii ◽  
Yusuke Matsuya ◽  
Ryosuke Mori ◽  
Joma Oikawa ◽  
...  
Keyword(s):  
Biological Effects ◽  
Absorbed Dose ◽  
Strand Break ◽  
Double Strand Break ◽  
Weighting Factor ◽  
Energy Concentration ◽  
X Rays ◽  
Dna Double Strand Break ◽  
The Impact

AbstractRadiation weighting factor wR for photons and electrons has been defined as unity independently of the energy of the particles. However, the biological effects depend on the incident energies according to in vitro experimental data. In this study, we have quantified the energy concentration along electron tracks in terms of dose-mean lineal energy (yD) on chromosome (micro-meter) and DNA (nano-meter) order scales by Monte Carlo simulations, and evaluated the impact of photon energies on DNA double-strand break (DNA-DSB) induction from an experimental study of irradiated cells. Our simulation result shows that the yD values for diagnostic X-rays (60–250 kVp) are higher than that for therapeutic X-rays (linac 6 MV), which agrees well with the tissue equivalent proportional counter (TEPC) measurements. The relation between the yD values and the numbers of γ-H2AX foci for various photon energy spectra suggests that low energy X-rays induce DNA-DSB more efficiently than higher energy X-rays even at the same absorbed dose (e.g., 1.0 Gy). The relative biological effectiveness based on DNA-DSBs number (RBEDSB) is proportionally enhanced as the yD value increases, demonstrating that the biological impact of the photon irradiation depends on energy concentration along radiation tracks of electrons produced in the bio-tissues. Ultimately, our study implies that the value of wR for photons varies depending on their energies.

scholarly journals SAT-434 Phenotype and Genotype Analysis of Patients with Resistance to Thyroid Hormone β: A Single-Center Experience

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Karn Wejaphikul ◽  
Prapai Dejkhamron ◽  
Stefan Groeneweg ◽  
W Edward Visser ◽  
Kevalee Unachak ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mutation Analysis ◽  
Novel Mutation ◽  
Family Members ◽  
Antithyroid Drugs ◽  
Thyroid Function Tests ◽  
Resistance To Thyroid Hormone ◽  
The Mean ◽  
The Impact

Abstract Introduction Resistance to thyroid hormone β (RTHβ) is caused by mutations in THRB, the gene that encodes thyroid hormone receptor β. The clinical phenotype is variable and may include goiter, tachycardia, and learning disability with or without hyperactive behavior. The biochemical hallmark of RTHβ is elevated T4 and T3 with non-suppressed TSH concentrations. We here describe the phenotype and genotype of three Thai patients diagnosed with RTHβ in a pediatric referral center. Patients had previously been misdiagnosed and inappropriately treated with antithyroid drugs (ATDs). Methods Clinical features and thyroid function tests (TFTs) of three unrelated RTHβ patients were retrospectively reviewed. Genomic DNA of the RTHβ patients and affected family members was amplified for exon 7-10 of the THRB gene and sequenced to identify mutation by Sanger sequencing. The impact of the p.L341V novel mutation on the affinity for T3 and T3-induced transcriptional activity was previously determined in vitro. Results Three female patients were diagnosed with RTHβ. All of them had been misdiagnosed with hyperthyroidism and treated with ATDs prior to referral. The mean age at diagnosis was 8 years. The main presenting symptoms were diffuse goiter and tachycardia. The mean duration of ATD treatment was 3 years. During the treatment, patients had fluctuating thyroid hormone and increased TSH levels. An older sister and mother of one patient also had similar TFTs abnormalities, for which the mother had undergone a subtotal thyroidectomy. RTHβ was diagnosed based on the high FT3 and FT4 with normal (non-suppressed) TSH concentrations and confirmed by mutation analysis. Anti-thyroid peroxidase, anti-thyroglobulin, and TSH receptor antibody (TRAb) were negative, excluding autoimmune thyroid disease. Heterozygous missense mutations of the THRB gene were identified in all patients and affected family members. Two mutations had been previously reported (p.R243W and p.L456F), and one mutation was novel (p.L341V). In vitro studies confirmed an important role of Leu341 in T3 binding of the TRβ and functional impairment of the p.L341V novel mutation and were reported separately. According to available literature, only nine Thai RTHβ patients (in three families) carrying three different mutations (p.G251V, p.M313T, and p.A317T) had been previously reported. Goiter was the most common clinical finding, and almost all patients had a history of receiving unnecessary treatment with ATDs. Conclusion We report a series of RTHβ patients carrying THRB gene mutations, including one novel mutation (p.L341V). Clinicians should be alert that RTHβ can be found in patients with goiter and tachycardia. Elevated T4 and T3 with non-suppressed TSH concentration is the main diagnostic clue for this disease. Mutation analysis allows definitive diagnosis of RTHβ and may help to avoid potential misdiagnosis and improper treatment.

Impact Deposition of Radon Progeny (218Po ,214Po and 210Po) on the Surface of Human Blood: In Vitro Study

2011 ◽  
Vol 110-116 ◽  
pp. 2004-2009 ◽  
Author(s):  
Asaad Hamid Ismail ◽  
Mohamad S. Jaafar
Keyword(s):  
Human Blood ◽  
Radon Concentration ◽  
Absorbed Dose ◽  
Blood Component ◽  
Good Efficiency ◽  
Present Design ◽  
Human Blood Samples ◽  
The Impact ◽  
Exposure Technique

This work presented new irradiation technique to estimate the impact of radon's progeny deposition on the human blood surface on some blood diseases, using CR-39Nuclear Track Detectors (NTDs). The results show that the present design has good efficiency and the loss rate of radon concentration was a little. Amount of the loss of radon concentration during the process of mixing blood component did not affect on the efficiency of exposure technique. Therefore, method of mixing blood component process was successful. As well as, human blood exposure to radon gas (2210±5.1Bq/m3) make thrombocytopenia, and no effect on red blood cell. And rate of radon absorbed dose into the human blood samples is high at 20 minutes.

Radiation detection materials for quality assurance and dose distribution assessment of small fields of high-energy X-rays

2020 ◽  
Vol 15 (04) ◽  
pp. P04001-P04001
Author(s):  
Sung Jin Noh ◽  
HyoJin Kim ◽  
Hyun Kim ◽  
Jeung kee Kim ◽  
Chi-Woong Mun ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Dose Distribution ◽  
Radiation Detection ◽  
High Energy ◽  
X Rays ◽  
Small Fields

scholarly journals Novel Organic Material Induced by Electron Beam Irradiation for Medical Application

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 306 ◽  
Author(s):  
Adrian Barylski ◽  
Krzysztof Aniołek ◽  
Andrzej S. Swinarew ◽  
Sławomir Kaptacz ◽  
Jadwiga Gabor ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Absorbed Dose ◽  
Medical Application ◽  
High Energy ◽  
Polymer Chains ◽  
Degree Of Crystallinity ◽  
Beam Irradiation ◽  
The Impact ◽  
The Degree Of Crystallinity

This study analyzed the effects of irradiation of polytetrafluoroethylene (PTFE) containing 40% of bronze using an electron beam with energy of 10 MeV. Dosages from 26 to156 kGy (2.6–15.6 Mrad) were used. The impact of a high-energy electron beam on the thermal, spectrophotometric, mechanical, and tribological properties was determined, and the results were compared with those obtained for pure PTFE. Thermal properties studies showed that such irradiation caused changes in melting temperature Tm and crystallization temperature Tc, an increase in crystallization heat ∆Hc, and a large increase in crystallinity χc proportional to the absorbed dose for both polymers. The addition of bronze decreased the degree of crystallinity of PTFE by twofold. Infrared spectroscopy (FTIR) studies confirmed that the main phenomenon associated with electron beam irradiation was the photodegradation of the polymer chains for both PTFE containing bronze and pure PTFE. This had a direct effect on the increase in the degree of crystallinity observed in DSC studies. The use of a bronze additive could lead to energy dissipation over the additive particles. An increase in hardness H and Young’s modulus E was also observed. The addition of bronze and the irradiation with an electron beam improved of the operational properties of PTFE.

scholarly journals Development and Qualification of a Pharmacodynamic Model for the Pronounced Inoculum Effect of Ceftazidime against Pseudomonas aeruginosa

2008 ◽  
Vol 53 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Jürgen B. Bulitta ◽  
Neang S. Ly ◽  
Jenny C. Yang ◽  
Alan Forrest ◽  
William J. Jusko ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Predictive Performance ◽  
Pkpd Model ◽  
Infection Models ◽  
The Mean ◽  
Inoculum Effect ◽  
Successful Replication ◽  
Time Kill ◽  
The Impact

ABSTRACT Evidence is mounting in support of the inoculum effect (i.e., slow killing at large initial inocula [CFUo]) for numerous antimicrobials against a variety of pathogens. Our objectives were to (i) determine the impact of the CFUo of Pseudomonas aeruginosa on ceftazidime activity and (ii) to develop and validate a pharmacokinetic/pharmacodynamic (PKPD) mathematical model accommodating a range of CFUo. Time-kill experiments using ceftazidime at seven concentrations up to 128 mg/liter (MIC, 2 mg/liter) were performed in duplicate against P. aeruginosa PAO1 at five CFUo from 105 to 109 CFU/ml. Samples were collected over 24 h and fit by candidate models in NONMEM VI and S-ADAPT 1.55 (all data were comodeled). External model qualification integrated data from eight previously published studies. Ceftazidime displayed approximately 3 to 4 log10 CFU/ml net killing at 106.2 CFUo and concentrations of 4 mg/liter (or higher), less than 1.6 log10 CFU/ml killing at 107.3 CFUo, and no killing at 108.0 CFUo for concentrations up to 128 mg/liter. The proposed mechanism-based model successfully described the inoculum effect and the concentration-independent lag time of killing. The mean generation time was 28.3 min. The effect of an autolysin was assumed to inhibit successful replication. Ceftazidime concentrations of 0.294 mg/liter stimulated the autolysin effect by 50%. The model was predictive in the internal cross-validation and had excellent in silico predictive performance for published studies of P. aeruginosa ATCC 27853 for various CFUo. The proposed PKPD model successfully described and predicted the pronounced inoculum effect of ceftazidime in vitro and integrated data from eight literature studies to support translation from time-kill experiments to in vitro infection models.

Energy-Shunting Hip Padding System Attenuates Femoral Impact Force in a Simulated Fall

1995 ◽  
Vol 117 (4) ◽  
pp. 409-413 ◽  
Author(s):  
S. N. Robinovitch ◽  
W. C. Hayes ◽  
T. A. McMahon
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Impact Force ◽  
The Elderly ◽  
Impact Behavior ◽  
Human Female ◽  
Female Pelvis ◽  
The Mean ◽  
The Impact

Recent studies suggest that hip padding systems reduce the incidence of hip fractures during falls. However, no data exist on the force attenuating capacity of hip pads under realistic fall impact conditions, and thus it is difficult to compare the protective merit of various pad designs. Our goal is to design a comfortable hip padding system which reduces femoral impact force in a fall below the mean force required to fracture the elderly cadaveric femur. In pursuit of this objective, we designed and constructed a hip pad testing system consisting of an impact pendulum and surrogate human pelvis. We then developed a hip pad containing a shear-thickening material which allows for shunting of the impact energy away from the femur and into the surrounding soft tissue. Finally, we conducted experiments to assess whether the surrogate pelvis accurately represents the impact behavior of the human female pelvis in a fall, and to determine whether our energy-shunting pad attenuates femoral impact force in a fall more effectively than seven available padding systems. We found the surrogate pelvis accurately represented the human female pelvis in regional variation in soft tissue stiffness, total effective stiffness and damping, and impact force attenuation provided by trochanteric soft tissues. We also found that our padding system attenuated femoral impact force by 65 percent, thereby providing two times the force attenuation of the next best system. Moreover, the energy-shunting pad was the only system capable of lowering femoral impact force well below the mean force required to fracture the elderly femur in a fall loading configuration. These results suggest that the force attenuating potential of hip pads which focus on shunting energy away from the femur is superior to those which rely on absorbing energy in the pad material. While these in-vitro results are encouraging, carefully designed prospective clinical trials will be necessary to determine the efficacy of these approaches to hip fracture prevention.

scholarly journals Vitrification of Human In-Vitro Matured Oocytes: Effects on Mitochondrial Ultrastructure and Oxygen Consumption

2019 ◽  
Vol 01 (03) ◽  
pp. 131-135
Author(s):  
Shubiao Han ◽  
Wei Han ◽  
Xiaodong Zhang ◽  
Junxia Liu ◽  
Guoning Huang
Keyword(s):  
Oxygen Consumption ◽  
Formation Rate ◽  
Control Group ◽  
Mitochondrial Morphology ◽  
Blastocyst Development ◽  
Dynamic Changes ◽  
The Mean ◽  
The Impact ◽  
Normal Fertilization

Background: This study was conducted to evaluate the impact of vitrification on mitochondrial of human IVM oocytes. Methods: A total of 401 immature oocytes were obtained from ovarian stimulated cycles, which were randomly divided into fresh and vitrification groups after IVM. According to the cultured time after thawing, the vitrification groups were divided into 0 hours (0 h), 2 hours (2 h), or 4 hours (4 h) subgroups. Mitochondrial morphology and oxygen consumption were compared among the four groups. After fertilization by ICSI, normal fertilization, cleaved embryos, and blastocyst formation rate were also calculated. Results: The mean gray value of mitochondria structure was significantly decreased in 0 h and 2 h groups when compared to control group (0.48 ± 0.09, 0.50 ± 0.36 vs. 0.61 ± 0.12, respectively; P [Formula: see text] 0.05), and recovered (0.61 ± 0.24 vs. 0.61 ± 0.12, P [Formula: see text] 0.05) in 4 h group. In addition, oxygen consumption was also significantly decreased in 0 h and 2 h groups compared to fresh (2.91 ± 0.77 fmol/s, 3.26 ± 1.34 fmol/s vs. 3.96 ± 1.44 fmol/s, respectively; P [Formula: see text] 0.05), and recovered after 4 h culture (3.96 ± 1.44 fmol/s vs. 4.41 ± 1.38 fmol/s, respectively; P [Formula: see text] 0.05). The percentage of normal fertilization and cleaved embryos were no differences among the four groups, however, blastocyst development rate was significantly lower in 0 h group. Conclusion: These results indicate that during the vitrification process, the oxygen consumption and mitochondrial structure of oocytes may undergo temporary dynamic changes, but appear to recover by 4 hours.

A comparison of absorbed dose standards for high-energy X-rays

1993 ◽  
Vol 38 (12) ◽  
pp. 1937-1955 ◽  
Author(s):  
K R Shortt ◽  
C K Ross ◽  
M Schneider ◽  
K Hohlfeld ◽  
M Roos ◽  
...  
Keyword(s):  
Absorbed Dose ◽  
High Energy ◽  
X Rays

184 EFFECTS OF X-RAY ELECTROMAGNETIC RADIATION ON BOVINE OOCYTE DEVELOPMENT

2010 ◽  
Vol 22 (1) ◽  
pp. 250
Author(s):  
W. E. Snyder ◽  
J. T. Aaltonen ◽  
H. D. Sigal ◽  
N. M. Loskutoff
Keyword(s):  
Electromagnetic Radiation ◽  
High Energy ◽  
X Rays ◽  
Embryo Production ◽  
Chi Square ◽  
X Ray ◽  
Chi Square Test ◽  
Bovine Oocytes ◽  
Experimental Group

This study examined the effects of X-rays on bovine oocytes used for in vitro embryo production. In recent years, airport security has become more stringent and the use of X-ray screening may be required for all items, which could be problematic when transporting oocytes. Ionizing radiation such as X-rays are high-energy particles that can penetrate into the nucleus of a cell and cause single and double-strand breaks in the DNA chain. Oocytes exposed to X-ray radiation may have DNA damage affecting maturation, fertilization, and embryonic development. Bovine ovaries obtained from a local abattoir were used to collect immature oocytes by follicular aspiration. The oocytes were divided into a control group and an experimental group then placed in maturation medium. The oocytes in the experimental group were placed in a hospital X-ray machine with a single exposure of 100 mA, 120 kVp for 0.3 s. This exposure challenged the oocytes with a comparable, calculated amount of mrems equivalent to a single screening from an airport X-ray machine (30 mrems). After X-ray exposure, the experimental group was cultured with the control at 37°C and 5% CO2. After 18 h, cryopreserved bovine sperm were thawed and processed using BoviPure (Nidacon International, Mölndal, Sweden) density gradient centrifugation and the oocytes were inseminated with 1 × 106 sperm in fertilization medium at 37°C and 5% CO2. After 24 h, both groups were transferred to 50-μL droplets of G1 medium (Vitrolife, Göteborg, Sweden) at 37°C and 6% CO2 and both were transferred into G2 medium after 72 h. Development of the oocytes was scored after an additional 72 h. Results were based on 2 criteria: the percent cleaved (presumptive fertilization) and the percent cleaved that developed to morula and blastocyst stages. The results indicated no significant difference in the percentages of oocytes cleaving after insemination for the control and experimental groups (P = 0.403, chi-square test). However, there was a significant increase (P = 0.037, chi-square test) in the percentages of morulae and blastocysts developing in the control (non-irradiated) v. experimental (X-rayed) groups. The outcome of this study cautions on the potential damage caused to bovine oocytes used for embryo production in vitro when exposed to X-ray electromagnetic radiation during routine air transport screening operations. Table 1.

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