Toxicity Assessment of 91-Day Repeated Inhalation Exposure to an Indoor School Air Mixture of PCBs

2022 ◽  
Author(s):  
Hui Wang ◽  
Andrea Adamcakova-Dodd ◽  
Hans-Joachim Lehmler ◽  
Keri C. Hornbuckle ◽  
Peter S. Thorne
Keyword(s):  
Inhalation Exposure ◽  
Toxicity Assessment

A 26-Week Toxicity Assessment of AIR001 (Sodium Nitrite) by Inhalation Exposure in Rats and by Intravenous Administration in Dogs

2014 ◽  
Vol 33 (3) ◽  
pp. 162-174 ◽  
Author(s):  
Jeffrey Tepper ◽  
Ricardo Ochoa ◽  
Peter Rix ◽  
Gary Elliott ◽  
Niel Hoglen ◽  
...  
Keyword(s):  
Sodium Nitrite ◽  
Inhalation Exposure ◽  
Health Benefit ◽  
Toxicity Assessment ◽  
Potential Health ◽  
Potential Health Benefit ◽  
Margin Of Safety ◽  
Pulmonary Arterial ◽  
Exposure Levels ◽  
Adequate Margin

Historically, nitrogen oxides (NOx) in food, drinking water, as well as in the atmosphere have been believed to be associated with adverse health consequences. More recently, NOx have been implicated in normal homeostatic regulation, and exogenous administration has been associated with health benefits. One such potential health benefit is the prospect that inhaled nitrite will lower pulmonary blood pressure (BP) in patients with pulmonary arterial hypertension (PAH), a disease with poor prognosis due to the lack of effective treatment. To characterize potential chronic toxicity associated with inhaled AIR001 (sodium nitrite) for use in the treatment of PAH, 26-week exposures to AIR001 were carried out by inhalation administration in rats and by intravenous infusion in dogs. The studies revealed that methemoglobinemia was the primary adverse effect in both species. Methemoglobin levels less than 40% were well tolerated in both species, while levels greater than 50% methemoglobin caused death in some rats. Additionally, a decrease in systemic BP was also observed with inhaled AIR001 exposure in dogs. These acute secondary and exaggerated pharmacological effects occurred daily throughout the 26-week treatment period. Chronic exposure did not alter the magnitude of either methemoglobinemia or hypotension or result in additional toxicity or compensatory responses. Based on the exposure levels that produced these pharmacodynamic responses in animals, relative to those measured in early clinical studies, it appears that an adequate margin of safety exists to support the continued clinical development of inhaled AIR001.

Toxic effects of inhaled DMMP on the kidneys of Fischer-344 rats

1987 ◽  
Vol 45 ◽  
pp. 880-881
Author(s):  
D.R. Mattie ◽  
C.J. Hixson
Keyword(s):  
Left Kidney ◽  
Inhalation Exposure ◽  
Electron Microscopic Examination ◽  
Exposure Period ◽  
Male Rats ◽  
Continuous Exposure ◽  
Fischer 344 Rats ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Fischer 344

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.

Evaluation of hippocampus in rhesus monkeys after chronic (1-year) inhalation exposure to marijuana: I. Electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 398-399
Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Rhesus Monkeys ◽  
Low Dose ◽  
Inhalation Exposure ◽  
Synaptic Cleft ◽  
High Dose ◽  
Withdrawal Time ◽  
Treatment Groups ◽  
Ultrastructural Evidence ◽  
Male Rhesus

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.

Evaluating Performance Effects of Low-Level Inhalation Exposure to Nerve Agents in Rats

2004 ◽  
Author(s):  
Raymond F. Genovese ◽  
◽  
Sara J. Shippee ◽  
Jessica Bonnell ◽  
Bernard J. Benton ◽  
...  
Keyword(s):  
Inhalation Exposure ◽  
Nerve Agents ◽  
Low Level ◽  
Performance Effects

217. Design and Operation of a Popcorn Butter Flavoring Inhalation Exposure System

2002 ◽  
Author(s):  
T. Goldsmith ◽  
D. Frazer ◽  
W. McKinney ◽  
W. Jones
Keyword(s):  
Inhalation Exposure ◽  
Exposure System

Effect of carbofuran on quantitative and qualitative alterations in haemolymph of larva of Oryctes rhinoceros L. (Coleoptera: Scarabaeidae)

ENTOMON ◽  
2020 ◽  
Vol 44 (4) ◽  
pp. 293-300
Author(s):  
V.S. Salini
Keyword(s):  
Oral Route ◽  
Toxicity Assessment ◽  
Haematological Parameters ◽  
Oryctes Rhinoceros ◽  
Total Haemocyte Count ◽  
Differential Haemocyte Count ◽  
Third Instar Larvae

Investigation to evaluate the toxicity of carbofuran pesticides on haematological parameters of third instar larvae of Oryctes rhinoceros L. Indicated alterations in total haemocyte count and differential haemocyte count for toxicity assessment. Various doses of carbofuran (0.05g, 0.010g and 0.015 g) applied on insect through oral route and its impact after 24 hours of its application revealed that various doses of carbofuran exert specific alterations in both total and differential haemocytes of insect haemolymph.

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