Neurobehavioral Effects of Cyclohexane in Rat and Human

2009 ◽  
Vol 28 (6) ◽  
pp. 488-497 ◽  
Author(s):  
J. H. C. M. Lammers ◽  
H. H. Emmen ◽  
H. Muijser ◽  
E. M. G. Hoogendijk ◽  
R. H. McKee ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Discrimination Performance ◽  
Internal Exposure ◽  
Psychomotor Speed ◽  
Significant Treatment ◽  
High Exposure ◽  
Observational Measures ◽  
Human Volunteers ◽  
Neurobehavioral Effects

The neurobehavioral effects of inhaled cyclohexane in rats and humans are investigated to define relationships between internal doses and acute central nervous system effects. Rats are exposed for 3 consecutive days at target concentrations of 0, 1.4, 8, and 28 g/m3, 8 h/d. Measurements include standardized observational measures, spontaneous motor activity assessments, and learned visual discrimination performance. Cyclohexane concentrations in blood and brain are measured to assess internal exposure. Human volunteers are exposed for 4 hours to 86 or 860 mg/m3 in 2 test sessions. Neurobehavioral effects are measured using a computerized neurobehavioral test battery. In rats, there are slight reductions in psychomotor speed in the high-exposure group but minimal central nervous system effects. In humans, there are no significant treatment-related effects at the levels tested.

Neurobehavioral Effects of Acute Exposure to Aromatic Hydrocarbons

2010 ◽  
Vol 29 (3) ◽  
pp. 277-290 ◽  
Author(s):  
Richard H. McKee ◽  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
D. E. Owen ◽  
B. M. Kulig
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
High Exposure ◽  
Molecular Weights ◽  
Trimethyl Benzene ◽  
The Central Nervous System ◽  
Exposure Levels ◽  
Alkyl Benzenes ◽  
Neurobehavioral Effects

This article reports the results of neurobehavioral tests on representative aromatic constituents, specifically C9 to C11 species. The testing evaluated effects in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. Exposures ranging from 600 to 5000 mg/m3, depending on the molecular weights of the specific aromatic constituents, produced minor, reversible effects on the central nervous system (CNS), particularly in the domains of gait and visual discrimination. There was little evidence of effects at lower exposure levels. There was some evidence of respiratory effects at 5000 mg/m3 in 1 study, and there were also minor changes in body weight and temperature. The CNS effects became less pronounced with repeated exposures, corresponding to lower concentrations in the brain of 1 representative substance, 1,2,4-trimethyl benzene (TMB). At high exposure levels, the alkyl benzenes apparently induced their own metabolism, increasing elimination rates.

scholarly journals Physiologically Based Pharmacokinetic Modeling of Cyclohexane as a Tool for Integrating Animal and Human Test Data

2009 ◽  
Vol 28 (6) ◽  
pp. 498-509 ◽  
Author(s):  
A. M. Hissink ◽  
B. M. Kulig ◽  
J. Kruse ◽  
A. P. Freidig ◽  
M. Verwei ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Pharmacokinetic Model ◽  
Physiologically Based Pharmacokinetic ◽  
Human Volunteers ◽  
Model Predictions ◽  
Physiologically Based ◽  
Exhaled Air ◽  
Effect Level ◽  
Exposure Levels

This report describes a physiologically based pharmacokinetic model for cyclohexane and its use in comparing internal doses in rats and volunteers following inhalation exposures. Parameters describing saturable metabolism of cyclohexane are measured in rats and used along with experimentally determined partition coefficients. The model is evaluated by comparing predicted blood and brain concentrations to data from studies in rats and then allometrically scaling the results to humans. Levels of cyclohexane in blood and exhaled air are measured in human volunteers and compared with model values. The model predicts that exposure of volunteers to cyclohexane at levels of 4100 mg/m3 (∼1200 ppm) will result in brain levels similar to those in rats exposed to 8000 mg/m3 (the no-effect level for acute central nervous system effects). There are no acute central nervous system effects in humans exposed to 860 mg/m3, consistent with model predictions that current occupational exposure levels for cyclohexane protect against acute central nervous system effects.

scholarly journals Toxic Effects of Mercury on the Cardiovascular and Central Nervous Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Bruna Fernandes Azevedo ◽  
Lorena Barros Furieri ◽  
Franck Maciel Peçanha ◽  
Giulia Alessandra Wiggers ◽  
Paula Frizera Vassallo ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Endothelial Function ◽  
Environmental Contamination ◽  
Human Activities ◽  
Behavioral Changes ◽  
Low Doses ◽  
High Exposure ◽  
Central Nervous Systems ◽  
The Central Nervous System

Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced.

Neurobehavioral Effects of Acute Exposure to Isoparaffinic and Cycloparaffinic Hydrocarbons

2011 ◽  
Vol 30 (6) ◽  
pp. 715-734 ◽  
Author(s):  
Richard H. McKee ◽  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
David E. Owen
Keyword(s):  
Central Nervous System ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
Occupational Exposure Limits ◽  
Exposure Limits ◽  
Discrimination Testing ◽  
Effect Level ◽  
Neurobehavioral Effects ◽  
Cns Effects

This article reports neurobehavioral tests in rats with C5-C11 isoparaffinic and cycloparaffinic hydrocarbons. Testing, conducted shortly after exposure, evaluated the effects in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. Isopentane and cyclopentane did not produce any evidence of acute central nervous system (CNS) effects at levels up to 20 000 mg/m3. A C6/C7 mixed cycloparaffinic solvent produced minor, reversible changes in latency to response in visual discrimination testing at 14 000 mg/m3; the no-effect level was 4200 mg/m3. A C8 isoparaffin produced no effects at 14 000 mg/m3, the highest level tested. A C9/C11 isoparaffinic solvent produced minor acute CNS effects at 5000 mg/m3, with 1500 mg/m3 as the no-effect level. A C10 cycloparaffinic solvent did not produce any statistically significant CNS effects at 5000 mg/m3. These studies were designed to provide data that may be useful in setting occupational exposure limits for C5-C11 isoparaffinic and cycloparaffinic hydrocarbons.

Neurobehavioral Effects of Acute Exposure to Normal (n-) Paraffins

2011 ◽  
Vol 30 (1) ◽  
pp. 47-58 ◽  
Author(s):  
J. H. C. M. Lammers ◽  
H. Muijser ◽  
D. E. Owen ◽  
B.M. Kulig ◽  
R. H. McKee
Keyword(s):  
Molecular Weight ◽  
Central Nervous System ◽  
Visual Discrimination ◽  
Discrimination Performance ◽  
Clinical Effects ◽  
Compelling Evidence ◽  
Effect Level ◽  
Neurobehavioral Effects ◽  
Cns Effects ◽  
Metabolic Induction

This article reports the results of neurobehavioral tests on C5-C10 normal paraffinic constituents (n-paraffins). Shortly after exposure, effects were evaluated in several domains including clinical effects, motor activity, functional observations, and visual discrimination performance. The representative C5 n-paraffin, n-pentane, did not produce any evidence of acute central nervous system (CNS) effects at levels up to 20 000 mg/m3. Similarly, there was no compelling evidence that n-octane (C8) produced CNS effects at 14 000 mg/m3, the highest concentration tested. n-decane (C10) produced minor, reversible acute CNS effects at 5000 mg/m3, with 1500 mg/m3 as the no-effect level. Consistent with literature data, there seemed to be a relationship between increasing molecular weight up to C10 and acute CNS effects. However, the CNS effects were reversible. Repeated exposures did not provide evidence of metabolic induction.

Neurotropic enteroviruses co-opt “fair-weather-friend” commensal gut microbiota to drive host infection and central nervous system disturbances

2019 ◽  
Vol 42 ◽  
Author(s):  
Kevin B. Clark
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Gut Bacteria ◽  
Infection Cycle ◽  
Fair Weather ◽  
Host Health ◽  
Microbe Interactions ◽  
Animal Hosts ◽  
Host Infection ◽  
Neuropsychiatric Conditions

Abstract Some neurotropic enteroviruses hijack Trojan horse/raft commensal gut bacteria to render devastating biomimicking cryptic attacks on human/animal hosts. Such virus-microbe interactions manipulate hosts’ gut-brain axes with accompanying infection-cycle-optimizing central nervous system (CNS) disturbances, including severe neurodevelopmental, neuromotor, and neuropsychiatric conditions. Co-opted bacteria thus indirectly influence host health, development, behavior, and mind as possible “fair-weather-friend” symbionts, switching from commensal to context-dependent pathogen-like strategies benefiting gut-bacteria fitness.

Sign in / Sign up

Export Citation Format

Share Document