Workplace Inhalation Exposure to Engineered Nanomaterials: Detection, Measurement, and Assessment

2014 ◽  
pp. 97-116
2020 ◽  
Vol 21 (19) ◽  
pp. 7310
Author(s):  
Dorothy J. You ◽  
James C. Bonner

Engineered nanomaterials (ENMs) are products of the emerging nanotechnology industry and many different types of ENMs have been shown to cause chronic inflammation in the lungs of rodents after inhalation exposure, suggesting a risk to human health. Due to the increasing demand and use of ENMs in a variety of products, a careful evaluation of the risks to human health is urgently needed. An assessment of the immunotoxicity of ENMs should consider susceptibility factors including sex, pre-existing diseases, deficiency of specific genes encoding proteins involved in the innate or adaptive immune response, and co-exposures to other chemicals. This review will address evidence from experimental animal models that highlights some important issues of susceptibility to chronic lung inflammation and systemic immune dysfunction after pulmonary exposure to ENMs.


Author(s):  
D.R. Mattie ◽  
C.J. Hixson

Dimethylmethylphosphonate (DMMP) is a simple organophosphate used industrially as a flame retardant and to lower viscosity in polyester and epoxy resins. The military considered the use of DMMP as a nerve gas simulant. Since military use of DMMP involved exposure by inhalation, there was a need for a subchronic inhalation exposure to DMMP to fully investigate its toxic potential.Male Fischer-344 rats were exposed to 25 ppm or 250 ppm DMMP vapor on a continuous basis for 90 days. An equal number of control rats were sham-exposed. Following the 90-day continuous exposure period, 15 male rats were sacrificed from each group. Two rats from each group had the left kidney perfused for electron microscopic examination. The kidneys were perfused from a height of 150 cm water with 1% glutaraldehyde in Sorensen's 0.1M phosphate buffer pH 7.2. An additional kidney was taken from a rat in each group and fixed by immersion in 2.5% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer pH 7.4. A portion of the 9 kidneys collected for electron microscopy were processed into Epon 812. Thin sections, stained with uranyl acetate and lead citrate, were examined with a JEOL 100B Transmission Electron Microscope. Microvilli height was measured on photographs of the cells of proximal tubules. This data, along with morphologic features of the cells, allows the proximal convoluted tubules (PCT) to be identified as being S1, S2, or S3 segment PCT.


Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  

Exposure of rhesus monkeys (Macaca mulatta) to marijuana via inhalation or to intravenous delta-9-tetrahydrocannabinol (THC), reportedly caused ultrastructural evidence of increased synaptic width. Chronic marijuana smoke in a single rhesus monkey examined after a six month withdrawal time caused ultrastructure changes in the septal, hippocampal and amygdala regions; the synaptic cleft was widened, electron opaque material was found in the cleft and in the pre- and postsynaptic regions, with some clumping of the synaptic vesicles. The objective of our study was to assess neuropathological alterations produced by chronic inhalation of marijuana smoke.Nineteen male rhesus monkeys, 3-5 years of age and weighing 3-8 kg, were divided into four treatment groups: a) sham control, b) placebo smoke (7 days/ week) c) low dose marijuana (2 times/week with 5 days/week sham) and d) high dose marijuana (7 times/week). A smoke exposure consisted of smoke from one cigarette (2.6% THC) burned down to 10 mm butt length. Smoke was administered via smoke generator (ADL II, Arthur D. Little, Inc. Cambridge, MA) and nose-mouth only masks (local production) equipped with one-way valves.


Author(s):  
Raymond F. Genovese ◽  
◽  
Sara J. Shippee ◽  
Jessica Bonnell ◽  
Bernard J. Benton ◽  
...  

2002 ◽  
Author(s):  
T. Goldsmith ◽  
D. Frazer ◽  
W. McKinney ◽  
W. Jones

Author(s):  
М. S. Saypullaev ◽  
А. U. Koychuev ◽  
Т. B. Mirzoeva

The successful conduct of disinfection measures largely depends on the availability of veterinary practice a highly efficient, environmentally safe disinfectants. In this regard, finding new highly efficient disinfectant remains relevant. Studies found that the "Polied" (OOO "Razvitie XXI Vek, Russia) can be attributed to the highly efficient and environmentally friendly means. Solutions "Polied" have a high disinfectant activity against smooth and rough surfaces in the laboratory against gram-positive, gram-negative bacteria, mycobacteria and spores of microorganisms. Studies have established that solutions should be "Polied" obezzarajivatmi E. coli (EA 1257) concentrations of 0.1% on smooth surfaces and Staphylococcus aureus concentration of 0.05% in 1 hour from the calculation of 0.25-0.3 litres/m2. Disinfection of rough test surfaces against Escherichia coli and Staphylococcus aureus occurred after treatment with 0,3% solution of 3-hour exposure, at a rate of 0.5 l/m2. It was also found that 1.0% solution "Polied" fully obezzarazhivatel test the surface of mycobacteria (PCs-5) and at double the 0.6% concentration for 24 hours. Disinfection of rough test surfaces contaminated with spores of B. cereus (PCs 96) was achieved with a 4.0% solution at twice the irrigation rate of 0.5 l/m2 at an exposure of 24 hours. Toxicity solutions of the drug "Polied" refer to "moderate" threat (hazard class 3) and low-hazard substances (4 hazard class) when applied to the skin, mucous membranes of the eyes, and inhalation exposure on the respiratory system.


Sign in / Sign up

Export Citation Format

Share Document