Mitotic Delay in More Mature Erythroblasts of the Dog, Induced in Vivo by Sublethal Doses of X-Rays

1964 ◽  
Vol 21 (3) ◽  
pp. 413 ◽  
Author(s):  
N. Odartchenko ◽  
H. Cottier ◽  
L. E. Feinendegen ◽  
V. P. Bond
Keyword(s):  
X Rays ◽  
Mitotic Delay ◽  
Sublethal Doses

scholarly journals Radiosensitization of Prostate Cancers In Vitro and In Vivo to Erbium-filtered Orthovoltage X-rays Using Actively Targeted Gold Nanoparticles

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Allison M. Khoo ◽  
Sang Hyun Cho ◽  
Francisco J. Reynoso ◽  
Maureen Aliru ◽  
Kathryn Aziz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
X Rays ◽  
Prostate Cancers

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

scholarly journals In Vivo Usability Test of Vascular Intervention Robotic System Controlled by Two Types of Master Devices

2021 ◽  
Vol 11 (12) ◽  
pp. 5453
Author(s):  
Hwa-Seob Song ◽  
Jae-Hong Woo ◽  
Jong-Yun Won ◽  
Byung-Ju Yi
Keyword(s):  
Radiation Exposure ◽  
Animal Experiments ◽  
X Rays ◽  
Physical Damage ◽  
Vascular Intervention ◽  
Task Load ◽  
Usability Test ◽  
Usability Tests ◽  
System Usability Scale

Conventional vascular intervention (VI) procedures are typically performed manually under exposure to X-rays, whereby several problems are presented that need to be addressed owing to the patients and doctors being exposed to large amounts of radiation. In such cases, employing radiation protection units is not a long-term solution to avoid physical damage. Therefore, to overcome these issues, we propose a robotic VI system in this study. Moreover, we compare the extent of radiation exposure in the case of the conventional manual VI procedure with that in the case of the robotic procedure. The radiation exposure is then analyzed from the perspective of the doctor. Subsequently, the results of usability tests for two proposed master devices are presented in terms of the NASA task load index (NASA-TLX) and the system usability scale (SUS) score. To verify the effectiveness of the robotic VI system, animal experiments are conducted using a pig model. Among the two types of master devices tested with the proposed robotic VI system, the ergonomically designed 2-degree-of-freedom master device is found to be more effective than the joystick-type device in terms of the usability test scores. Hence, the proposed robotic VI procedure is shown to be advantageous in terms of reducing radiation exposure and improving usability.

scholarly journals THE EFFECTS OF ROENTGEN RAYS ON CELL-VIRUS ASSOCIATIONS

1943 ◽  
Vol 78 (4) ◽  
pp. 285-304 ◽  
Author(s):  
William F. Friedewald ◽  
Rubert S. Anderson
Keyword(s):  
X Rays ◽  
Pathological Changes ◽  
Cellular Division ◽  
Papilloma Virus ◽  
X Ray ◽  
Crude Extracts ◽  
Domestic Rabbits ◽  
Roentgen Rays

The virus-induced papillomas of cottontail as well as domestic rabbits regress completely within a few weeks when exposed to 5,000 r of x-ray irradiation. The x-rays do not immediately kill the papilloma cells, but lead to death by inhibiting cellular division and producing pathological changes in the cells which then continue to differentiate. The virus associated with the growths, however, not only persists in undiminished amount during regression, but often an increased yield of it can be obtained on extraction. The fibroma virus in crude extracts or in vivo is inactivated by far less irradiation than the papilloma virus. 10,000 r destroys 90 per cent or more of the infectivity of the fibroma virus, whereas at least 100,000 r is required to inactivate 50 per cent of the papilloma virus in extracts containing about the same amount of protein. No variant of the papilloma virus or fibroma virus has been encountered as a result of the irradiation.

scholarly journals A brain-penetrant microtubule-targeting agent that disrupts hallmarks of glioma tumorigenesis

2020 ◽  
Author(s):  
Eric A Horne ◽  
Philippe Diaz ◽  
Patrick J Cimino ◽  
Erik Jung ◽  
Cong Xu ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Mouse Model ◽  
Immunofluorescence Analysis ◽  
In Vivo Antitumor Activity ◽  
Microtubule Targeting Agents ◽  
Mitotic Delay ◽  
Tumor Mouse Model ◽  
In Vivo Testing ◽  
New Chemical Entity

Abstract Background Glioma is sensitive to microtubule-targeting agents (MTAs), but most MTAs do not cross the blood brain barrier (BBB). To address this limitation, we developed the new chemical entity, ST-401, a brain-penetrant MTA. Methods Synthesis of ST-401. Measures of MT assembly and dynamics. Cell proliferation and viability of patient-derived (PD) glioma in culture. Measure of tumor microtube (TM) parameters using immunofluorescence analysis and machine learning-based workflow. Pharmacokinetics (PK) and experimental toxicity in mice. In vivo antitumor activity in the RCAS/tv-a PDGFB-driven glioma (PDGFB-glioma) mouse model. Results We discovered that ST-401 disrupts microtubule (MT) function through gentle and reverisible reduction in MT assembly that triggers mitotic delay and cell death in interphase. ST-401 inhibits the formation of TMs, MT-rich structures that connect glioma to a network that promotes resistance to DNA damage. PK analysis of ST-401 in mice shows brain penetration reaching antitumor concentrations, and in vivo testing of ST-401 in a xenograft flank tumor mouse model demonstrates significant antitumor activity and no over toxicity in mice. In the PDGFB-glioma mouse model, ST-401 enhances the therapeutic efficacies of temozolomide (TMZ) and radiation therapy (RT). Conclusion Our study identifies hallmarks of glioma tumorigenesis that are sensitive to MTAs and reports ST-401 as a promising chemical scaffold to develop brain-penetrant MTAs.

scholarly journals Bystander Effect between Zebrafish Embryos in Vivo Induced by High-Dose X-rays

2013 ◽  
Vol 47 (12) ◽  
pp. 6368-6376 ◽  
Author(s):  
V. W. Y. Choi ◽  
C. Y. P. Ng ◽  
A. Kobayashi ◽  
T. Konishi ◽  
N. Suya ◽  
...  
Keyword(s):  
Bystander Effect ◽  
High Dose ◽  
Zebrafish Embryos ◽  
X Rays

scholarly journals A hydroxyapatite phantom material for the calibration of in vivo x-ray fluorescence systems of bone strontium and lead quantification

2021 ◽  
Author(s):  
Eric Da Silva
Keyword(s):  
Monte Carlo ◽  
Soft Tissue ◽  
Monte Carlo Simulations ◽  
Calibration Procedure ◽  
X Rays ◽  
X Ray ◽  
Total Phosphate Concentration ◽  
High Concentrations ◽  
Phantom Material

A hydroxyaptite [HAp; Ca5(PO4)3OH] phantom material was developed with the goal of improving the calibration protocol of the 125I-induced in vivo X-ray fluorescence (IVXRF) system of bone strontium quantification with further application to other IVXRF bone metal quantification systems, particulary those associated with bone lead quantification. It was found that calcium can be prepared pure of inherent contamination from strontium (and other elements) through a hydroxide precipitation producing pure Ca(OH)2, thereby, allowing for the production of a blank phantom which has not been available previously. The pure Ca(OH)2 can then be used for the preparation of pure CaHPO4 ⋅ 2H2O. A solid state pure HAp phantom can then be prepared by reaction of Ca(OH)2 and CaHPO4 ⋅ 2H2O mixed as to produce a Ca/P mole ratio of 1.67, that in HAp and the mineral phase of bone, in the presence of a setting solution prepared as to raise the total phosphate concentration of the solution by increasing the solubility CaHPO4 ⋅ 2H2O and thereby precipitating HAp. The procedure can only be used to prepare phantoms in which doping with the analyte does not disturb the Ca/P ratio substantially. In cases in which phantoms are to be prepared with high concentrations of strontium, the cement mixture can be modified as to introduce strontium in the form of Sr(OH)2 ⋅ 8H2O as to maintain a (Ca + Sr)/P ratio of 1.67. It was found by both X-ray diffraction spectrometry and Raman spectroscopy studies that strontium substitutes for calcium as in bone when preparing phantoms by this route. The necessity for the blank bone phantoms was assessed through the first blank bone phantom measurement and Monte Carlo simulations. It was found that for the 125I-induced IVXRF system of bone strontium quantification, the source, 125I brachytherapy seeds may be contributing coherently and incoherently scattered zirconium X-rays to the measured spectra, thereby requiring the use of the blank bone phantom as a means of improving the overall quantification methodology. Monte Carlo simulations were employed to evaluate any improvement by the introduction of HAp phantoms into the coherent normalization-based calibration procedure. It was found that HAp phantoms remove the need for a coherent conversion factor (CCF) thereby potentially increasing accuracy of the quantification. Further, it was found that in order for soft tissue attenuation corrections to be possible using spectroscopic information alone, HAp along with a suitable soft tissue surrogate material need to be employed. The HAp phantom material was used for the evaluations of portable X-ray analyzer systems for their potential for IVXRF quantification of lead and strontium with a focus on a comparison between tungsten, silver and rhodium target systems. Silver and rhodium target X-ray tube systems were found to be comparable for this quantification.

Cytogenetic Damage of Human Lymphocytes in Humanized Mice Exposed to Neutrons and X Rays 24 h After Exposure

2021 ◽  
Vol 161 (6-7) ◽  
pp. 352-361
Author(s):  
Qi Wang ◽  
Younghyun Lee ◽  
Monica Pujol-Canadell ◽  
Jay R. Perrier ◽  
Lubomir Smilenov ◽  
...  
Keyword(s):  
Dna Damage ◽  
Radiation Exposure ◽  
Human Lymphocytes ◽  
Absorbed Dose ◽  
Chromosome 1 ◽  
X Rays ◽  
Chromosomal Dna ◽  
Humanized Mouse Model ◽  
Significant Difference

Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.

scholarly journals CHARACTERIZATION OF A CR51-LABELED ENDOTOXIN AND ITS IDENTIFICATION IN PLASMA AND URINE AFTER PARENTERAL ADMINISTRATION

1963 ◽  
Vol 117 (4) ◽  
pp. 561-571 ◽  
Author(s):  
Louis Chedid ◽  
Robert C. Skarnes ◽  
Monique Parant
Keyword(s):  
Intravenous Administration ◽  
Sublethal Dose ◽  
Plasma Samples ◽  
Agar Diffusion ◽  
Degraded Material ◽  
Sublethal Doses ◽  
Heavy Fractions ◽  
Urine Specimens

The incubation of endotoxin with Na2Cr51O4 yielded a product which was well labeled. That the label was fixed on the endotoxin itself was shown by autoradiography on specific lines of precipitation formed in agar. Ultracentrifugation at 40,000 RPM sedimented 80 per cent of the total weight of the starting Boivin preparation. Agar diffusion patterns with subsequent autoradiographs demonstrated that the chromium tag was associated only with the heavy fractions of the pellet. The supernatant contained precipitable, but unlabeled endotoxin. Toxicity measurements showed that more than 99 per cent of the total toxicity resided in the pellet fractions. The chromate-tagged endotoxin was specifically identified in plasma samples taken up to 6 hours after intravenous administration of LD50 or sublethal doses. The endotoxin was not totally detoxified in vivo since plasma collected 6 hours after the injection of even the sublethal dose was toxic when assayed in adrenalectomized mice. The endotoxin was specifically identified in urine specimens but it was no longer toxic or radioactive. Agar diffusion experiments indicated that only degraded material was present.

Sign in / Sign up

Export Citation Format

Share Document