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1.
Int J Part Ther ; 11: 100006, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38757081

RESUMEN

Purpose: In breast cancer, improved treatment approaches that reduce injury to lung tissue and early diagnosis and intervention for lung toxicity are increasingly important in survivorship. The aims of this study are to (1) compare lung tissue radiographic changes in women treated with conventional photon radiation therapy and those treated with proton therapy (PT), (2) assess the volume of lung irradiated to 5 Gy (V5) and 20 Gy (V20) by treatment modality, and (3) quantify the effects of V5, V20, time, and smoking history on the severity of tissue radiographic changes. Patients and Methods: A prospective observational study of female breast cancer patients was conducted to monitor postradiation subclinical lung tissue radiographic changes. Repeated follow-up x-ray computed tomography scans were acquired through 2 years after treatment. In-house software was used to quantify an internally normalized measure of pulmonary tissue density change over time from the computed tomography scans, emphasizing the 6- and 12-month time points. Results: Compared with photon therapy, PT was associated with significantly lower lung V5 and V20. Lung V20 (but not V5) correlated significantly with increased subclinical lung tissue radiographic changes 6 months after treatment, and neither correlated with lung effects at 12 months. Significant lung tissue density changes were present in photon therapy patients at 6 and 12 months but not in PT patients. Significant lung tissue density change persisted at 12 months in ever-smokers but not in never-smokers. Conclusion: Patients treated with PT had significantly lower radiation exposure to the lungs and less statistically significant tissue density change, suggesting decreased injury and/or improved recovery compared to photon therapy. These findings motivate additional studies in larger, randomized, and more diverse cohorts to further investigate the contributions of treatment modality and smoking regarding the short- and long-term radiographic effects of radiation on lung tissue.

2.
Radiat Res ; 202(1): 70-79, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38661544

RESUMEN

Optimal triage biodosimetry would include risk stratification within minutes, and it would provide useful triage despite heterogeneous dosimetry, cytokine therapy, mixed radiation quality, race, and age. For regulatory approval, the U.S. Food and Drug Administration (FDA) Biodosimetry Guidance requires suitability for purpose and a validated species-independent mechanism. Circulating cell-free DNA (cfDNA) concentration assays may provide such triage information. To test this hypothesis, cfDNA concentrations were measured in unprocessed monkey plasma using a branched DNA (bDNA) technique with a laboratory developed test. The cfDNA levels, along with hematopoietic parameters, were measured over a 7-day period in Rhesus macaques receiving total body radiation doses ranging from 1 to 6.5 Gy. Low-dose irradiation (0-2 Gy) was easily distinguished from high-dose whole-body exposures (5.5 and 6.5 Gy). Fold changes in cfDNA in the monkey model were comparable to those measured in a bone marrow transplant patient receiving a supralethal radiation dose, suggesting that the lethal threshold of cfDNA concentrations may be similar across species. Average cfDNA levels were 50 ± 40 ng/mL [±1 standard deviation (SD)] pre-irradiation, 120 ± 13 ng/mL at 1 Gy; 242 ± 71 ng/mL at 2 Gy; 607 ± 54 at 5.5 Gy; and 1585 ± 351 at 6.5 Gy (±1 SD). There was an exponential increase in cfDNA concentration with radiation dose. Comparison of the monkey model with the mouse model and the Guskova model, developed using Chernobyl responder data, further demonstrated correlation across species, supporting a similar mechanism of action. The test is available commercially in a Clinical Laboratory Improvement Amendments (CLIA) ready form in the U.S. and the European Union. The remaining challenges include developing methods for further simplification of specimen processing and assay evaluation, as well as more accurate calibration of the triage category with cfDNA concentration cutoffs.


Asunto(s)
Ácidos Nucleicos Libres de Células , Macaca mulatta , Triaje , Animales , Ácidos Nucleicos Libres de Células/sangre , Triaje/métodos , Humanos , Masculino , Ratones , Relación Dosis-Respuesta en la Radiación , Radiometría/métodos , Irradiación Corporal Total
5.
Radiat Prot Dosimetry ; 199(14): 1450-1459, 2023 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-37721059

RESUMEN

Extremely high dose rate radiation delivery (FLASH) for cancer treatment has been shown to produce less damage to normal tissues while having the same radiotoxic effect on tumor tissue (referred to as the FLASH effect). Research on the FLASH effect has two very pertinent implications for the field of biodosimetry: (1) FLASH is a good model to simulate delivery of prompt radiation from the initial moments after detonating a nuclear weapon and (2) the FLASH effect elucidates how dose rate impacts the biological mechanisms that underlie most types of biological biodosimetry. The impact of dose rate will likely differ for different types of biodosimetry, depending on the specific underlying mechanisms. The greatest impact of FLASH effects is likely to occur for assays based on biological responses to radiation damage, but the consequences of differential effects of dose rates on the accuracy of dose estimates has not been taken into account.


Asunto(s)
Bioensayo , Armas Nucleares
6.
Radiat Prot Dosimetry ; 199(14): 1539-1550, 2023 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-37721065

RESUMEN

Following large-scale radiation events, an overwhelming number of people will potentially need mitigators or treatment for radiation-induced injuries. This necessitates having methods to triage people based on their dose and its likely distribution, so life-saving treatment is directed only to people who can benefit from such care. Using estimates of victims following an improvised nuclear device striking a major city, we illustrate a two-tier approach to triage. At the second tier, after first removing most who would not benefit from care, biodosimetry should provide accurate dose estimates and determine whether the dose was heterogeneous. We illustrate the value of using in vivo electron paramagnetic resonance nail biodosimetry to rapidly assess dose and determine its heterogeneity using independent measurements of nails from the hands and feet. Having previously established its feasibility, we review the benefits and challenges of potential improvements of this method that would make it particularly suitable for tier 2 triage. Improvements, guided by a user-centered approach to design and development, include expanding its capability to make simultaneous, independent measurements and improving its precision and universality.


Asunto(s)
Uñas , Traumatismos por Radiación , Humanos , Triaje , Espectroscopía de Resonancia por Spin del Electrón , Mano
7.
Physiol Rep ; 10(7): e15241, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35388988

RESUMEN

Although full-length fibroblast growth factor 7 (FGF7) blocks cyclophosphamide-induced urothelial apoptosis in mice, limitations include high production costs because of its large size. We previously identified a small peptide derived from FGF2 that mitigated acute radiation syndrome as well as full-length FGF2. Based on the sequence of the FGF2 peptide, we synthesized a corresponding 19 amino acid FGF7 peptide (FGF7p). Our objectives were to determine if systemic FGF7p triggered the downstream targets and protected against cyclophosphamide bladder injury similar to full-length FGF7. We administered FGF7p or vehicle subcutaneously (SQ) to mice subjected to no injury or intraperitoneal (IP) cyclophosphamide and harvested bladders 1 day after injury. We then performed hematoxylin and eosin, TUNEL and immunofluorescence (IF) staining. In uninjured mice, a 20 mg/kg threshold FGF7p dose induced expression of phosphorylated (activated) FRS2α (pFRS2α), and pAKT in urothelium (consistent with cytoprotective effects of FGF7). We then gave FGF7p (20 mg/kg) or vehicle at 72 and 48 h prior to cyclophosphamide. One day after injury, TUNEL staining revealed many more apoptotic urothelial cells with vehicle treatment versus FGF7p treatment. IF for pAKT and readouts of two anti-apoptotic AKT targets (BAD and mTORC1) revealed minimal staining with vehicle treatment, but strong urothelial expression for all markers with FGF7p treatment. In conclusion, FGF7p appears to block bladder urothelial apoptosis via AKT and its targets, similar to FGF7. FGF7p is much more inexpensive to make and has a longer shelf life and higher purity than FGF7.


Asunto(s)
Vejiga Urinaria , Urotelio , Animales , Ciclofosfamida/farmacología , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Factor 7 de Crecimiento de Fibroblastos/farmacología , Ratones , Péptidos/farmacología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Vejiga Urinaria/metabolismo , Urotelio/metabolismo
8.
Int J Part Ther ; 8(3): 28-35, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35127973

RESUMEN

BACKGROUND: After radiation therapy (RT), circulating plasma cell-free DNA (cfDNA) released in response to RT damage to tissue can be measured within hours. We examined for a correlation between cfDNA measured during the first week of therapy and early and late gastrointestinal (GI) and genitourinary (GU) toxicity. MATERIAL AND METHODS: Patients were eligible for enrollment if they planned to receive proton or photon RT for nonmetastatic prostate cancer in the setting of an intact prostate or after prostatectomy. Blood was collected before treatment and on sequential treatment days for the first full week of therapy. Toxicity assessments were performed at baseline, weekly during RT, and 6 months and 12 months after RT. Data were analyzed to examine correlations among patient-reported GI and GU toxicities. RESULTS: Fifty-four patients were evaluable for this study. Four (7%) and 3 (6%) patients experienced acute and late grade 2 GI toxicity, respectively. Twenty-two (41%) and 18 (35%) patients experienced acute and late grade 2 GU toxicity, respectively. No patients developed grade 3 or higher toxicity. Grade 2 acute GI toxicity, but not grade 2 acute GU toxicity, was significantly correlated with pre-RT cfDNA levels and on all days 1, 2, 3, 4, and 5 of RT (P < .005). Grade 2 late GI toxicity, but not GU toxicity, was significantly correlated with pre-RT cfDNA levels (P = .021). CONCLUSIONS: Based on this preliminary study, cfDNA levels can potentially predict the subset of patients destined to develop GI toxicity during prostate cancer treatment. Given that the toxicity profiles of the various fractionations and modalities are highly similar, the data support the expectation that cfDNA could provide a biological estimate to complement the dose-volume histogram. A test of this hypothesis is under evaluation in a National Cancer Institute-funded multi-institutional study.

11.
Int J Part Ther ; 7(2): 21-30, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33274254

RESUMEN

PURPOSE: The RadTox assay measures circulating cell-free DNA released in response to radiotherapy (RT)-induced tissue damage. The primary objectives for this clinical trial were to determine whether cell-free DNA numbers measured by the RadTox assay are (1) correlated with body integral dose, (2) lower with proton RT compared with photon RT, and (3) higher with larger prostate cancer RT fields. PATIENTS AND METHODS: Patients planned to receive proton or photon RT for nonmetastatic prostate cancer in the setting of an intact prostate or postprostatectomy were eligible for the trial. Plasma was collected pre-RT and at 5 additional daily collection points beginning 24 hours after the initiation of RT. Data from 54 evaluable patients were analyzed to examine any correlations among RadTox scores with body-integral dose, RT modality (photon versus proton), and RT field size (prostate or prostate bed versus whole pelvis). RESULTS: Body integral dose was significantly associated with the peak post-RT RadTox score (P = .04). Patients who received photon RT had a significant increase in peak post-RT RadTox score (P = .04), average post-RT RadTox score (P = .04), and day-2 RadTox score (all minus the pre-RT values for each patient) as compared with patients who received proton RT. Field size was not significantly associated with RadTox score. CONCLUSION: RadTox is correlated with body integral dose and correctly predicts which patients receive proton versus photon RT. Data collection remains ongoing for patient-reported RT toxicity outcomes to determine whether RadTox scores are correlated with toxicity.

12.
Health Phys ; 119(1): 72-82, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32175928

RESUMEN

An effective medical response to a large-scale radiation event requires prompt and effective initial triage so that appropriate care can be provided to individuals with significant risk for severe acute radiation injury. Arguably, it would be advantageous to use injury rather than radiation dose for the initial assessment; i.e., use bioassays of biological damage. Such assays would be based on changes in intrinsic biological response elements; e.g., up- or down-regulation of genes, proteins, metabolites, blood cell counts, chromosomal aberrations, micronuclei, micro-RNA, cytokines, or transcriptomes. Using a framework to evaluate the feasibility of biodosimetry for triaging up to a million people in less than a week following a major radiation event, Part 1 analyzes the logistical feasibility and clinical needs for ensuring that biomarkers of organ-specific injury could be effectively used in this context. We conclude that the decision to use biomarkers of organ-specific injury would greatly benefit by first having independent knowledge of whether the person's exposure was heterogeneous and, if so, what was the dose distribution (to determine which organs were exposed to high doses). In Part 2, we describe how these two essential needs for prior information (heterogeneity and dose distribution) could be obtained by using in vivo nail dosimetry. This novel physical biodosimetry method can also meet the needs for initial triage, providing non-invasive, point-of-care measurements made by non-experts with immediate dose estimates for four separate anatomical sites. Additionally, it uniquely provides immediate information as to whether the exposure was homogeneous and, if not, it can estimate the dose distribution. We conclude that combining the capability of methods such as in vivo EPR nail dosimetry with bioassays to predict organ-specific damage would allow effective use of medical resources to save lives.


Asunto(s)
Biomarcadores/análisis , Traumatismos por Radiación/diagnóstico , Medición de Riesgo/métodos , Triaje/métodos , Bioensayo , Recuento de Células Sanguíneas/métodos , Aberraciones Cromosómicas/efectos de la radiación , Regulación de la Expresión Génica/efectos de la radiación , Humanos , Metaboloma/efectos de la radiación , Sistemas de Atención de Punto , Dosis de Radiación , Exposición a la Radiación/efectos adversos , Radiometría
13.
Thorac Cancer ; 10(7): 1605-1611, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31228354

RESUMEN

BACKGROUND: Radiation-induced tumor immunity (RITI) influences primary tumor growth and development of metastases in preclinical cancer models with conventional radiotherapy. Antigen-specific immune responses have also been shown for prostate cancer treated with radiotherapy. We examined whether RITI can be induced in patients with non-small cell lung cancer (NSCLC) following proton radiotherapy. METHODS: Pre- and post-radiotherapy plasma samples from 26 patients with nonmetastatic NSCLC who received radiotherapy between 2010 and 2012 were evaluated by western blotting for IgG and IgM bands to assess RITI response to tumor antigens from lung cancer cell lines. Statistical analysis was used to evaluate any correlation among IgG or IgM and clinical outcomes. RESULTS: Twenty-one patients received proton therapy at 2 GyRBE/fraction (n = 17) or 6-12 Gy/fraction (n = 4); five received photon therapy at 2-2.5 GyRBE/fraction. Compared with the pretreatment baseline, new IgG or IgM binding was detected in 27% and 50% of patients, respectively. New IgG bands were detected in the 25-37 kD, 50-75 kD, and 75-100 kD ranges. New IgM bands were detected in the 20-25 kD, 25-37 kD, 37-50 kD, 50-75 kD, and 75-100 kD ranges. There was no difference in IgG and/or IgM RITI response in patients treated with photons versus protons, or in patients who received SBRT compared to standard fractionation (P > 0.05). There was no difference in overall survival, metastasis-free survival, or local control based on IgG and/or IgM RITI response (P > 0.05). CONCLUSION: RITI can be induced in patients with NSCLC through upregulated IgG and/or IgM. RITI response was not associated with proton versus photon therapy or with clinical outcomes in this small cohort and should be examined in a larger cohort in future studies.


Asunto(s)
Anticuerpos Antineoplásicos/inmunología , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Inmunoglobulina G/metabolismo , Inmunoglobulina M/metabolismo , Neoplasias Pulmonares/radioterapia , Terapia de Protones/efectos adversos , Células A549 , Anciano , Anciano de 80 o más Años , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Línea Celular Tumoral , Fraccionamiento de la Dosis de Radiación , Femenino , Humanos , Neoplasias Pulmonares/inmunología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Análisis de Supervivencia , Resultado del Tratamiento
14.
Eur J Pharm Biopharm ; 135: 83-93, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30582960

RESUMEN

Fibroblast growth factor peptide (FGF-P) is a polypeptide analog of FGF-2 that could be a potential mitigation and treatment agent for radiation syndromes. Prior to conducting preclinical pharmacokinetics, we developed and validated the LC-MS/MS bioanalytical method for determination of FGF-P in rat plasma for the first time. FGF-P was extracted from rat plasma using the protein precipitation technique followed liquid-liquid extraction using dichloromethane as a solvent. The mobile phases consisted of two components: (a) 0.1% formic acid in water; and (b) acetonitrile: 0.1% formic acid in water (95:5) under gradient elution. The validated method was also successfully applied to a pharmacokinetic study of FGF-P (10 mg/kg, intravenous) in Wistar rats. The method proved to be specific, accurate, precise, and linear over the concentration range of 2-500 ng/mL with coefficient of determination greater than 0.99 in all validation batches. The within-run and between-run accuracy was 87.97-115.00% with a precision of less than 14%. The mean recoveries ranged from 88.14% to 101.73%. The stability of the compound in plasma samples was proven under various storage conditions. After intravenous administration of FGF-P (10 mg/kg) the C0 was 70.4 µg/mL and the AUC was 86.2 µg*min/mL.


Asunto(s)
Cromatografía Liquida/métodos , Factor 2 de Crecimiento de Fibroblastos/farmacocinética , Fragmentos de Péptidos/farmacocinética , Espectrometría de Masas en Tándem/métodos , Administración Intravenosa , Animales , Área Bajo la Curva , Estabilidad de Medicamentos , Almacenaje de Medicamentos , Factor 2 de Crecimiento de Fibroblastos/administración & dosificación , Extracción Líquido-Líquido , Fragmentos de Péptidos/administración & dosificación , Ratas , Ratas Wistar , Reproducibilidad de los Resultados
15.
Health Phys ; 115(1): 140-150, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29787440

RESUMEN

Instrumentation and application methodologies for rapidly and accurately estimating individual ionizing radiation dose are needed for on-site triage in a radiological/nuclear event. One such methodology is an in vivo X-band, electron paramagnetic resonance, physically based dosimetry method to directly measure the radiation-induced signal in fingernails. The primary components under development are key instrument features, such as resonators with unique geometries that allow for large sampling volumes but limit radiation-induced signal measurements to the nail plate, and methodological approaches for addressing interfering signals in the nail and for calibrating dose from radiation-induced signal measurements. One resonator development highlighted here is a surface resonator array designed to reduce signal detection losses due to the soft tissues underlying the nail plate. Several surface resonator array geometries, along with ergonomic features to stabilize fingernail placement, have been tested in tissue-equivalent nail models and in vivo nail measurements of healthy volunteers using simulated radiation-induced signals in their fingernails. These studies demonstrated radiation-induced signal detection sensitivities and quantitation limits approaching the clinically relevant range of ≤ 10 Gy. Studies of the capabilities of the current instrument suggest that a reduction in the variability in radiation-induced signal measurements can be obtained with refinements to the surface resonator array and ergonomic features of the human interface to the instrument. Additional studies are required before the quantitative limits of the assay can be determined for triage decisions in a field application of dosimetry. These include expanded in vivo nail studies and associated ex vivo nail studies to provide informed approaches to accommodate for a potential interfering native signal in the nails when calculating the radiation-induced signal from the nail plate spectral measurements and to provide a method for calibrating dose estimates from the radiation-induced signal measurements based on quantifying experiments in patients undergoing total-body irradiation or total-skin electron therapy.


Asunto(s)
Bioensayo/métodos , Espectroscopía de Resonancia por Spin del Electrón/métodos , Mecanotransducción Celular/efectos de la radiación , Uñas/química , Radiometría/métodos , Triaje/normas , Humanos , Uñas/efectos de la radiación , Dosis de Radiación
16.
Int J Radiat Biol ; 93(12): 1334-1342, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29063809

RESUMEN

PURPOSE: To investigate the late effects of thoracic region irradiation (TRI) on mouse body weight. MATERIALS AND METHODS: Female C57BL/6 mice were divided into nonirradiated, 5 Gy total body irradiation, 9 Gy sub-total body irradiation, and 12.5 Gy thoracic region irradiation (TRI) groups. Changes in mouse weight were monitored every other week at similar time points for 12 months. The anatomical characteristics of abdominal visceral fat distribution were recorded, and mitochondrial DNA copy number in the hearts and livers and lipid metabolic signaling in the liver were analyzed. Data were analyzed by one-way analysis of variance and a student's t-test. RESULTS: TRI led to a significant increase (p < .001) in body weight that was dependent on time and individuals [42.1% of mice were overweight (50% increase in body weight) 4 months post-TRI and 100% of mice were overweight at 10 months post-TRI]. Gross anatomical features of abdominal visceral fat distribution and storage in radiation-induced overweight/severely overweight mice were similar to those of high fat diet-induced overweight/severely overweight mice. The mitochondrial genome of heart and liver tissues from overweight/severely overweight mice had significantly (p < .05) decreased functional mitochondrial DNA copy number (ratios decreased from 1 to 0.71 or 0.49, respectively) and significantly (p < .05) increased mitochondrial DNA mutations (ratios increased from 1 to 3.21 or 1.83, respectively). CPT1 and IRS2 lipid metabolic signaling was significantly (p < .05-.01) decreased for both mRNA (fold decrease from 1 to 0.60 or 0.55, respectively) and protein (fold decrease from 1 to 0.62 or 0.19, respectively). CONCLUSIONS: TRI can cause mice to gain weight. These findings indicate that TRI can result in lipid metabolic abnormalities and provide a model to study the factors that result in these abnormalities.


Asunto(s)
Rayos gamma/efectos adversos , Obesidad/etiología , Tórax/efectos de la radiación , Animales , Peso Corporal/efectos de la radiación , Progresión de la Enfermedad , Femenino , Genoma Mitocondrial/efectos de la radiación , Metabolismo de los Lípidos/efectos de la radiación , Ratones , Ratones Endogámicos C57BL , Obesidad/genética , Obesidad/metabolismo , Obesidad/fisiopatología
17.
Radiat Prot Dosimetry ; 172(1-3): 112-120, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27522053

RESUMEN

Exposure of finger- and toe-nails to ionizing radiation generates an Electron Paramagnetic Resonance (EPR) signal whose intensity is dose dependent and stable at room temperature for several days. The dependency of the radiation-induced signal (RIS) on the received dose may be used as the basis for retrospective dosimetry of an individual's fortuitous exposure to ionizing radiation. Two radiation-induced signals, a quasi-stable (RIS2) and stable signal (RIS5), have been identified in nails irradiated up to a dose of 50 Gy. Using X-band EPR, both RIS signals exhibit a singlet line shape with a line width around 1.0 mT and an apparent g-value of 2.0044. In this work, we seek information on the exact chemical nature of the radiation-induced free radicals underlying the signal. This knowledge may provide insights into the reason for the discrepancy in the stabilities of the two RIS signals and help develop strategies for stabilizing the radicals in nails or devising methods for restoring the radicals after decay. In this work an analysis of high field (94 GHz and 240 GHz) EPR spectra of the RIS using quantum chemical calculations, the oxidation-reduction properties and the pH dependence of the signal intensities are used to show that spectroscopic and chemical properties of the RIS are consistent with a semiquinone-type radical underlying the RIS. It has been suggested that semiquinone radicals formed on trace amounts of melanin in nails are the basis for the RIS signals. However, based on the quantum chemical calculations and chemical properties of the RIS, it is likely that the radicals underlying this signal are generated from the radiolysis of L-3,4-dihydroxyphenylalanine (DOPA) amino acids in the keratin proteins. These DOPA amino acids are likely formed from the exogenous oxidation of tyrosine in keratin by the oxygen from the air prior to irradiation. We show that these DOPA amino acids can work as radical traps, capturing the highly reactive and unstable sulfur-based radicals and/or alkyl radicals generated during the radiation event and are converted to the more stable o-semiquinone anion-radicals. From this understanding of the oxidation-reduction properties of the RIS, it may be possible to regenerate the unstable RIS2 following its decay through treatment of nail clippings. However, the treatment used to recover the RIS2 also has the ability to recover an interfering, mechanically-induced signal (MIS) formed when the nail is clipped. Therefore, to use the recovered (regenerated) RIS2 to increase the detection limits and precision of the RIS measurements and, therefore, the dose estimates calculated from the RIS signal amplitudes, will require the application of methods to differentiate the RIS2 from the recovered MIS signal.


Asunto(s)
Bioensayo/métodos , Espectroscopía de Resonancia por Spin del Electrón/métodos , Modelos Biológicos , Modelos Químicos , Uñas/química , Uñas/efectos de la radiación , Monitoreo de Radiación/métodos , Biomarcadores/análisis , Simulación por Computador , Humanos , Teoría Cuántica , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
18.
Radiat Prot Dosimetry ; 172(1-3): 121-126, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27412507

RESUMEN

A new resonator for X-band in vivo EPR nail dosimetry, the dielectric-backed aperture resonator (DAR), is developed based on rectangular TE102 geometry. This novel geometry for surface spectroscopy improves at least a factor of 20 compared to a traditional non-backed aperture resonator. Such an increase in EPR sensitivity is achieved by using a non-resonant dielectric slab, placed on the aperture inside the cavity. The dielectric slab provides an increased magnetic field at the aperture and sample, while minimizing sensitive aperture resonance conditions. This work also introduces a DAR semi-spherical (SS)-TE011 geometry. The SS-TE011 geometry is attractive due to having twice the incident magnetic field at the aperture for a fixed input power. It has been shown that DAR provides sufficient sensitivity to make biologically relevant measurements both in vitro and in vivo Although in vivo tests have shown some effects of physiological motions that suggest the necessity of a more robust finger holder, equivalent dosimetry sensitivity of approximately 1.4 Gy has been demonstrated.


Asunto(s)
Bioensayo/instrumentación , Espectroscopía de Resonancia por Spin del Electrón/instrumentación , Uñas/química , Uñas/efectos de la radiación , Radiometría/instrumentación , Transductores , Impedancia Eléctrica , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Microondas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
19.
Bioorg Med Chem ; 24(18): 4263-4271, 2016 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-27448774

RESUMEN

In an effort to develop new drug candidates with enhanced anticancer activity, our team synthesized and assessed the cytotoxicity of a series of novel xanthone derivatives with two longer 3,6-disubstituted amine carbonyl methoxy side chains on either benzene ring in selected human cancer cell lines. An MTT assay revealed that a set of compounds with lower IC50 values than the positive control, 5-FU, exhibited greater anticancer effects. The most potent derivative (XD8) exhibited anticancer activity in MDA-MB-231, PC-3, A549, AsPC-1, and HCT116 cells lines with IC50 values of 8.06, 6.18, 4.59, 4.76, and 6.09µM, respectively. Cell cycle analysis and apoptosis activation suggested that the mechanism of action of these derivatives includes cell cycle regulation and apoptosis induction.


Asunto(s)
Antineoplásicos/farmacología , Xantonas/farmacología , Antineoplásicos/síntesis química , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Puntos de Control de la Fase G1 del Ciclo Celular/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Humanos , Relación Estructura-Actividad , Xantonas/síntesis química
20.
Health Phys ; 111(2): 169-82, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27356061

RESUMEN

The aim of this paper is to delineate characteristics of biodosimetry most suitable for assessing individuals who have potentially been exposed to significant radiation from a nuclear device explosion when the primary population targeted by the explosion and needing rapid assessment for triage is civilians vs. deployed military personnel. The authors first carry out a systematic analysis of the requirements for biodosimetry to meet the military's needs to assess deployed troops in a warfare situation, which include accomplishing the military mission. Then the military's special capabilities to respond and carry out biodosimetry for deployed troops in warfare are compared and contrasted systematically, in contrast to those available to respond and conduct biodosimetry for civilians who have been targeted by terrorists, for example. Then the effectiveness of different biodosimetry methods to address military vs. civilian needs and capabilities in these scenarios was compared and, using five representative types of biodosimetry with sufficient published data to be useful for the simulations, the number of individuals are estimated who could be assessed by military vs. civilian responders within the timeframe needed for triage decisions. Analyses based on these scenarios indicate that, in comparison to responses for a civilian population, a wartime military response for deployed troops has both more complex requirements for and greater capabilities to use different types of biodosimetry to evaluate radiation exposure in a very short timeframe after the exposure occurs. Greater complexity for the deployed military is based on factors such as a greater likelihood of partial or whole body exposure, conditions that include exposure to neutrons, and a greater likelihood of combined injury. These simulations showed, for both the military and civilian response, that a very fast rate of initiating the processing (24,000 d) is needed to have at least some methods capable of completing the assessment of 50,000 people within a 2- or 6-d timeframe following exposure. This in turn suggests a very high capacity (i.e., laboratories, devices, supplies and expertise) would be necessary to achieve these rates. These simulations also demonstrated the practical importance of the military's superior capacity to minimize time to transport samples to offsite facilities and use the results to carry out triage quickly. Assuming sufficient resources and the fastest daily rate to initiate processing victims, the military scenario revealed that two biodosimetry methods could achieve the necessary throughput to triage 50,000 victims in 2 d (i.e., the timeframe needed for injured victims), and all five achieved the targeted throughput within 6 d. In contrast, simulations based on the civilian scenario revealed that no method could process 50,000 people in 2 d and only two could succeed within 6 d.


Asunto(s)
Bioensayo/métodos , Personal Militar , Evaluación de Necesidades , Exposición a la Radiación/análisis , Traumatismos por Radiación/prevención & control , Monitoreo de Radiación/métodos , Defensa Civil/métodos , Incidentes con Víctimas en Masa , Medicina Militar/métodos , Guerra Nuclear , Traumatismos por Radiación/diagnóstico , Liberación de Radiactividad Peligrosa , Terrorismo , Triaje/métodos , Guerra
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