EXPERIMENTAL AND MATHEMATICAL MODELING OF THE IRON OXIDE NANOPARTICLE PULMONARY RETENTION AT LONG-TERM LOW-LEVEL INHALATION EXPOSURE

2017 ◽  
pp. 12-21
Author(s):  
M. P. Sutunkova ◽  
B. A. Katsnelson ◽  
L. I. Privalova ◽  
V. B. Gurvich ◽  
L. K. Konysheva ◽  
...  
Keyword(s):  
Inhalation Exposure ◽  
Iron Oxide Nanoparticle ◽  
Free Fluid ◽  
Compartment System ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Inhaled Nanoparticles ◽  
Electron Paramagnetic

Airborne Fe2O3 nanoparticles (NPs) with the mean diameter of 14±4 nm produced at spark ablation from 99.99% pure iron rods were fed into a «nose-only» exposure tower for rats exposed for 4 h a day, 5 days a week during 3, 6 or 10 months at a mean concentration of 1.14±0.01 mg/m3. Nanoparticles filtered out of the air exhausted from the exposure tower proved insoluble in de-ionized water but gradually dissolved in the cell free fluid supernatant produced by broncho-alveolar lavage and in the sterile bovine blood serum. The Fe2O3 content in lungs was measured by the Electron Paramagnetic Resonance (EPR) spectroscopy. NP retention in lungs and in brain was visualized with the Transmission Electron Microscopy (TEM). It was found a relatively low but significant pulmonary accumulation of Fe2O3, gradually increasing with time but tending to attain an equilibrium level. Besides, TEM-images showed nanoparticles retention within alveolocytes and the myelin sheaths of brain fibers associated with their ultrastructural damage. A multi compartment system model was developed and identified which describes toxicokinetics of inhaled nanoparticles after their deposition in the lower airways as a process controlled by their (a) high ability to penetrate through the alveolar membrane; (b) active endocytosis; (c) in vivo dissolution. However, in this particular study, dissolution-depending mechanisms proved to be dominant due to the rather high solubility of the finest Fe2O3-NPs in biological milieux.

Measurement of oxygen partial pressure, its control during hypoxia and hyperoxia, and its effect upon light emission in a bioluminescent elaterid larva

1999 ◽  
Vol 202 (19) ◽  
pp. 2631-2638 ◽  
Author(s):  
G.S. Timmins ◽  
C.A. Penatti ◽  
E.J. Bechara ◽  
H.M. Swartz
Keyword(s):  
Partial Pressure ◽  
Light Emission ◽  
Threshold Value ◽  
Respiratory Physiology ◽  
Paramagnetic Resonance ◽  
Epr Oximetry ◽  
Electron Paramagnetic ◽  
Long Term Measurement

This study investigates the respiratory physiology of bioluminescent larvae of Pyrearinus termitilluminans in relation to their tolerance to hypoxia and hyperoxia and to the supply of oxygen for bioluminescence. The partial pressure of oxygen (P(O2)) was measured within the bioluminescent prothorax by in vivo electron paramagnetic resonance (EPR) oximetry following acclimation of larvae to hypoxic, normoxic and hyperoxic (normobaric) atmospheres and during periods of bioluminescence (during normoxia). The P(O2) in the prothorax during exposure to an external P(O2) of 15.2, 160 and 760 mmHg was 10.3+/−2.6, 134+/−0.9 and 725+/−73 mmHg respectively (mean +/− s.d., N=5; 1 mmHg=0.1333 kPa). Oxygen supply to the larvae via gas exchange through the spiracles, measured by determining the rate of water loss, was also studied in the above atmospheres and was found not to be dependent upon P(O2). The data indicated that there is little to no active control of extracellular tissue P(O2) within the prothorax of these larvae. The reduction in prothorax P(O2) observed during either attack-response-provoked bioluminescence or sustained feeding-related bioluminescence in a normoxic atmosphere was variable, but fell within the range 10–25 mmHg. The effect of hypoxic atmospheres on bioluminescence was measured to estimate the intracellular P(O2) within the photocytes of the prothorax. Above a threshold value of 50–80 mmHg, bioluminescence was unaffected by P(O2). Below this threshold, an approximately linear relationship between P(O2) and bioluminescence was observed. Taken together with the extracellular P(O2) measurements, this suggests that control of P(O2) within the photocyte may occur. This work establishes that EPR oximetry is a valuable technique for long-term measurement of tissue P(O2) in insects and can provide valuable insights into their respiratory physiology. It also raises questions regarding the hypothesis that bioluminescence can have a significant antioxidative effect by reduction of prothorax P(O2)through oxygen consumption.

ДИНИТРОЗИЛЬНЫЕ КОМПЛЕКСЫ ЖЕЛЕЗА C ТИОЛСОДЕРЖАЩИМИ ЛИГАНДАМИ ПРЕДСТАВЛЕНЫ В ЖИВЫХ ОРГАНИЗМАХ В ОСНОВНОМ ИХ БИЯДЕРНОЙ ФОРМОЙ

2020 ◽  
Vol 65 (6) ◽  
pp. 1142-1153
Author(s):  
В.Д. Микоян ◽  
◽  
Е.Н. Бургова ◽  
Р.Р. Бородулин ◽  
А.Ф. Ванин ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Sodium Nitrite ◽  
Iron Complexes ◽  
Paramagnetic Resonance ◽  
First Case ◽  
Dinitrosyl Iron ◽  
Electron Paramagnetic ◽  
Dinitrosyl Complexes

The number of mononitrosyl iron complexes with diethyldithiocarbamate, formed in the liver of mice in vivo and in vitro after intraperitoneal injection of binuclear dinitrosyl iron complexes with N-acetyl-L-cysteine or glutathione, S-nitrosoglutathione, sodium nitrite or the vasodilating drug Isoket® was assessed by electron paramagnetic resonance (EPR). The number of the said complexes, in contrast to the complexes, formed after nitrite or Isoket administration, the level of which sharply increased after treatment of liver preparations with a strong reducing agent - dithionite, did not change in the presence of dithionite. It was concluded that, in the first case, EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate in the absence and presence of dithionite appeared as a result of the reaction of NO formed from nitrite with Fe2+-dieth- yldithiocarbamate and Fe3+-diethyldithiocarbamate complexes, respectively. In the second case, mononitrosyl iron complexes with diethyldithiocarbamate appeared as a result of the transition of iron-mononitosyl fragments from ready-made iron-dinitrosyl groups of binuclear dinitrosyl complexes, which is three to four times higher than the content of the mononuclear form of these complexes in the tissue...

Evaluation of adriamycin nephropathy by an in vivo electron paramagnetic resonance

2005 ◽  
Vol 332 (2) ◽  
pp. 326-331 ◽  
Author(s):  
Takaaki Oteki ◽  
Sohji Nagase ◽  
Hidekatsu Yokoyama ◽  
Hiroaki Ohya ◽  
Takao Akatsuka ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Paramagnetic Resonance ◽  
Adriamycin Nephropathy ◽  
Electron Paramagnetic

Ge-Related Interfacial Defects in Sige Alloy Structures

1995 ◽  
Vol 405 ◽  
Author(s):  
Patricia J. Macfarlane ◽  
M. E. Zvanut ◽  
W. E. Carlos ◽  
M. E. Twigg ◽  
P. E. Thompson
Keyword(s):  
Depth Profile ◽  
Epr Spectra ◽  
Transmission Electron Micrograph ◽  
Dangling Bond ◽  
Electron Micrograph ◽  
Cross Sectional ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Interfacial Defects ◽  
Electron Paramagnetic

AbstractThis paper reports etching results supporting the identification of the SG1 center as a germanium dangling bond defect at the interface between an oxide and crystalline SiGe. The presence of this defect is significant because, like an analogous center in Si-based systems, it may alter the operation of any microelectronic or micro-optical device which incorporates an interface between SiGe and an overlying oxide. The samples examined are oxygen implanted SiGe layers in which the SG1 center is believed to occur at the interface between oxide precipitates and SiGe. Because of the center's apparent relation to the oxide precipitates distributed through layers of the sample, a depth profile assists in confirming the interfacial nature of the defect. We obtain a depth profile by comparing electron paramagnetic resonance (EPR) spectra of samples etched to decreasing thickness. EPR spectra indicate that the SG1 center decreases with depth in a manner that when correlated to a cross sectional transmission electron micrograph confirms the association with SiO2 and supports its location at the SiGe/SiO2 precipitate interface.

scholarly journals Long-term effects of carbon containing engineered nanomaterials and asbestos in the lung: one year postexposure comparisons

2014 ◽  
Vol 306 (2) ◽  
pp. L170-L182 ◽  
Author(s):  
Anna A. Shvedova ◽  
Naveena Yanamala ◽  
Elena R. Kisin ◽  
Alexey V. Tkach ◽  
Ashley R. Murray ◽  
...  
Keyword(s):  
Lung Tumor ◽  
Inhalation Exposure ◽  
Geometric Feature ◽  
Width Ratio ◽  
Long Term Effects ◽  
Genotoxic Effects ◽  
Pulmonary Exposure ◽  
Pharyngeal Aspiration

The hallmark geometric feature of single-walled carbon nanotubes (SWCNT) and carbon nanofibers (CNF), high length to width ratio, makes them similar to a hazardous agent, asbestos. Very limited data are available concerning long-term effects of pulmonary exposure to SWCNT or CNF. Here, we compared inflammatory, fibrogenic, and genotoxic effects of CNF, SWCNT, or asbestos in mice 1 yr after pharyngeal aspiration. In addition, we compared pulmonary responses to SWCNT by bolus dosing through pharyngeal aspiration and inhalation 5 h/day for 4 days, to evaluate the effect of dose rate. The aspiration studies showed that these particles can be visualized in the lung at 1 yr postexposure, whereas some translocate to lymphatics. All these particles induced chronic bronchopneumonia and lymphadenitis, accompanied by pulmonary fibrosis. CNF and asbestos were found to promote the greatest degree of inflammation, followed by SWCNT, whereas SWCNT were the most fibrogenic of these three particles. Furthermore, SWCNT induced cytogenetic alterations seen as micronuclei formation and nuclear protrusions in vivo. Importantly, inhalation exposure to SWCNT showed significantly greater inflammatory, fibrotic, and genotoxic effects than bolus pharyngeal aspiration. Finally, SWCNT and CNF, but not asbestos exposures, increased the incidence of K-ras oncogene mutations in the lung. No increased lung tumor incidence occurred after 1 yr postexposure to SWCNT, CNF, and asbestos. Overall, our data suggest that long-term pulmonary toxicity of SWCNT, CNF, and asbestos is defined, not only by their chemical composition, but also by the specific surface area and type of exposure.

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