Solvents

Question 1

Solvent

Answer 1

-any liquid that will solvate (dissolve) a solute
-low molecular weight organic compounds that are liquid
Properties:
-lipophilic
-lack of a charge
-natural or xenobiotics
-route of exposure=inhalation, ingestion, skin

Question 2

Ethanol effects on the brain

Answer 2

• readily moves into membranes, changing their fluidity
• GABA receptors agonist
  
  • damping neuronal signalling (sedative)
• antagonist for excitatory NMDA receptors
• release of dopamine and serotonin

Question 3

Alcohol and liver disease

Answer 3

• fatty liver=more than 5% fat deposits in liver cells
• cirrhosis=necrosis and fibrosis of liver cells
• induces CYP2E1, enhancing metabolism of other toxicants

Question 4

Fetal Alcohol syndrome

Answer 4

• severity depends on genetic background, ethanol exposure, nutritional status of mother
• causes learning disabilities, low birth weight, difficulty understanding consequences of actions, depression, OCD, physical disabilities, skeletal abnormalities

Question 5

Cause of FAS

Answer 5

• ROS
• inhibition of NMDA receptors=neuronal necrosis
• alteration of genes/proteins

Question 6

Effects of Ethanol

Answer 6

• Group 1 carcinogen
• Acetaldehyde metabolite=weak mutagen and carcinogen
• Solvent for carcinogens, enhancing their absorption
• Congeners (additives) influence carcinogenicity
• immune function suppressed
• absorption of nutrients are reduced by alcohol
• smoking and alcohol carcinogenesis is synergistic

Question 7

Effects of Methanol

Answer 7

• metabolized to carbon dioxide
• last reaction is slowest, levels of formate increase in the blood
• formate affect oxidative phosphorylation, production of ROS and leading to apoptosis
• poisoning causes blurred vision or blindness

Question 8

Benzene

Answer 8

• produced naturally
• exposure increases risk of acute myelogenous leukaemia (blood cancer)
• reduces the numbers of red and white blood cells and platelets produced by bone marrow
• metabolically activated by CYP2E1
• benzoquinones the ultimate toxic metabolites forming adducts to proteins and DNA

Question 9

toluene

Answer 9

• solvent used in paints, lacquers, thinners, glues
• absorbed through lungs
• accumulates in brain and adipose tissues
• causes tiredness, confusion, weakness, drunken-type actions, memory loss, nausea, loss of appetite, hearing and colour vision loss

Question 10

generalized solvent encephalopathy

Answer 10

• inhalation is inebriating (drunk feeling)
• interact with GABA, NMDA and serotonin receptors
• addiction and abuse
• teratogen (affect developing fetus)

Question 11

carbon tetrachloride

Answer 11

• xenobiotic
• solvent
• classic liver toxin-forms free radicles that acutely damage liver cell components
• ubiquitous in ambient air

Question 12

tetrachloroethylene

Answer 12

• liver toxicity:metabolized by a CYP to PERC oxide, triggering the multiplication of peroxisomes and generation of ROS
• kidney toxicity: damage kidney cells, decrease renal activity
• induce cancer in kidney cells
• association with esophageal cancers

Question 13

Anti-freeze or ethylene glycol

Answer 13

• exposure route: ingestion
• suicide attempts or substitute for ethanol
• acute poisoning: period of inebriation, cardiopulmonary stage (fast heart beat, pulmonary edema, and cardiac failure), kidney toxicity

Question 14

Ground water contamination by solvents

Answer 14

• aquifers
• benzene, toluene, ethylbenzene and tolulene
• use chlorine as a disinfectant
• produces chloroform
• levels of solvent are well below any potential toxic levels

Question 15

fracking

Answer 15

• obtain hydrocarbons from earth
• water, sand, and a mixture of chemicals are pumped into the ground to access oils and natural gas
• release methane
• benzene, xylene, chloroacetic acid

Question 16

volatile organics

Answer 16

• become gases or vapours
• indoor environments: indoor environments, video display units (toluene, styrene, cresol), photocopiers
• new car smell, air fresheners, perfumes and colognes