toxic agents II

Question 1

what is solvent?

Answer 1

• something that is used to dissolve, dilute, or disperse materials
• has variable lipophilicity and volatility

Question 2

factor that can make solvent cause adverse effects?

there are 6 factors!

Answer 2

1. toxicity/ carcinogenicity of solvent
2. exposure route
3. amount/ rate of exposure
4. duration of exposure
5. individual susceptibility
6. interactions with other chemicals

Question 3

what is Dichloromethane?

Answer 3

• used in industries, manufacturing of drugs (solvents)
• as degreasing agents, aerosol propellants, agriculture, food preparation (decaf coffee)
• route of exposure: inhalation
• rapidly absorbed and distributed (due to its lipophilicity)

Question 4

toxicity mechanism of DCM?

Answer 4

• CO (result of biotransformation of DCM) -> increase carboxyhemoglobin -> induce hypoxia -> cause neurological dysfunctions
• formaldehyde (DCM metabolites) -> is reactive with DNA -> produce DNA ss breaks -> cause carcinogenicity

Question 5

what is benzene? the route of exposure?

Answer 5

• ex: gasoline, automobile exhaust, forest fire, cigarette
• route of exposure: inhalation

Question 6

toxicity mechanism of benzene?

Answer 6

1. benzene oxide and phenolic conjugate travel from liver to bone marrow
2. is then hydroxylated and oxidized to quinones -> will bind to DNA, RNA and protein
3. metabolites interact with target cells in bone marrow
4. form initiated and mutated target cells
5. selective proliferation of the mutated cells
6. cause leukemia (hematopoietic toxicity)

Question 7

what is radiation?

Answer 7

• energy emitted as particles/ waves
• harmful, heat energy transferred to the object
• ionizing radiation caused by unstable atoms giving off energy to reach a more stable state

Question 8

what are considered ionizing radiation?

where can it be found?

Answer 8

any types of particulate (alpha, beta, proton, neutron)/ electromagnetic waves (gamma and X-rays) that carries enough energy to ionize or remove electron from an atom
* can break atomic bonds and create charged atomic particles
can be found in:
* medical application (X-ray, CT scan, radiotherapy)
* environment exposure
* consumer products (2%)

Question 9

mechanism of radiation?

Answer 9

has potential direct effects on DNA molecules (can either):
* modify bases chemically
* breakage to one or both sugar-phosphate backbones
* break hydrogen bonds

Question 10

what are radioactive materials (radionucleotide)

Answer 10

• radioactive atom: spontaneously emit energrtic waves (radiation)
• radioactivity: atoms spontaneously disintegrates, emit both particles and energy as they transform into a different and more stable atoms

Question 11

what is radon?

Answer 11

• high exposure -> cause high risk of lung cancer and leukemia
• release alpha and beta particles in body