Arsenic

Question 1

what are a few uses for arsenic today

Answer 1

pesticides, herbicides, metal production, leukemia drug

Question 2

where is arsenic found

Answer 2

naturally or can contaminate water and fish

Question 3

what are 2 common forms of arsenic

Answer 3

trivalent (arsenite) and pentavalent (arsenate) forms

Question 4

what happens to arsenate in the body

Answer 4

arsenate reductase turns it into arsenite

Question 5

what happens to arsenite in the body

Answer 5

arsenite methyltransferase (AS3MT) turns it into MMA5+

Question 6

what happens to MMA5+ in the body

Answer 6

arsenite methyltransferase (AS3MT) turns it into MMA3+

Question 7

what happens to MMA3+ in the body

Answer 7

arsenite methyltransferase (AS3MT) turns it into DMA5+

Question 8

what happens to DMA5+ in the body

Answer 8

arsenite methyltransferase (AS3MT) turns it into DMA3+

Question 9

what happens to DMA3+ in the body

Answer 9

arsenite methyltransferase (AS3MT) turns it into TMAO

Question 10

what is the order of compounds in arsenic breakdown (7)

Answer 10

arsenate
arsenite
MMA5+
MMA3+
DMA5+
DMA3+
TMAO

Question 11

what is the order of toxicity of these compounds

arsenate
arsenite
MMA5+
MMA3+
DMA5+

Answer 11

MMA3+
 >>
arsenite
>
arsenate
>
MMA5+ = DMA5+

Question 12

is TMAO toxic

Answer 12

no

Question 13

is MMA5+ or MMA3+ more toxic

Answer 13

MMA3+ much more toxic

Question 14

is arsenite or arsenate more toxic

Answer 14

arsenite

Question 15

how is inorganic arsenic absorbed best + %

Answer 15

through GI 80-90%

Question 16

how is inorganic arsenic absorbed inneficiently + %

Answer 16

through skin, but you can still get toxicity

Question 17

what are 3 ways you can absorb arsenic

Answer 17

GI skin and inhalation

Question 18

what type of arsenic is best absorbed via inhalation

Answer 18

arsene, trivalent arsenic oxide

Question 19

where does arsenic concentrate

Answer 19

hair and fingernails

Question 20

how much arsenic ingestion is fatal

Answer 20

70-180mg

Question 21

what are symptoms of acute poisoning of arsenic (6)

Answer 21

fever, anorexia, hepatomegaly, cardiac arrhythmia, GI damage, sensory loss

Question 22

what can acute poisoning of arsenic damage

Answer 22

mucous membranes of GI tract

Question 23

what happens to sensory system with acute arsenic + how long

Answer 23

sensory loss 1-2 weeks after initial exposure but often reversible

Question 24

what is a major target for chronic arsenic exposure

Answer 24

skin

Question 25

what happens to skin with chronic arsenic exposure

Answer 25

pigmentation changes, hyperkeratosis, alopecia

Question 26

what blood things happen with chronic arsenic exposure

Answer 26

bone marrow suppression, anemia

Question 27

what happens to nerves with chronic arsenic exposure

Answer 27

symmetrical sensorimotor polyneuropathy (tingling and loss of sensation)

Question 28

what is the classic symptom of chronic arsenic exposure

Answer 28

symmetrical sensorimotor polyneuropathy

Question 29

what kind of cancers happen with chronic arsenic exposure

Answer 29

skin lung liver GI

Question 30

what is the main mechanism of trivalent As toxicity

Answer 30

highly reactive with protein sulfhydryl groups

Question 31

how does trivalent As react highly with protein sulfhydryl groups

Answer 31

interferes with pyruvate dehydrogenase complex so then acetylCoA formation is inhibited

Question 32

what happens once trivalent As interferes with pyruvate dehydrogenase complex

Answer 32

acetylCoA formation from pyruvate is inhibited

Question 33

what happens once trivalent As interrupts oxidative phosphorylation (2)

Answer 33

less ATP is formed so then ROS production

Question 34

what happens with pentavalent forms of As (general)

Answer 34

it replaces phosphate

Question 35

what is arsenolysis

Answer 35

arsenic ions replace phosphate in high energy compounds, so instead of ATP fomring you get ADP-arsenate

Question 36

what happens with ATP levels in arsenolysis + result

Answer 36

they decrease, leading to cell death

Question 37

how many enzymes can arsenic inhibit

Answer 37

over 200 diff ones

Question 38

what kind of cell death does arsenic cause

Answer 38

induce MPT to cause apoptosis or necrosis

Question 39

how does arsenic cause cancer + which type of arsenic mostly

Answer 39

trivalent species, alters DNA methylation and repair, chromosomal abnormalities

Question 40

what do you use for cute arsenic poisoning

Answer 40

penicillamine or DMSA to chelate arsenic and promote renal excretion

Question 41

what do you do for chronic arsenic poisoning

Answer 41

reduce exposure, maybe DMPS may help symptoms

Question 42

does chelation help symptoms of chronic arsenic exposure

Answer 42

no evidence that it will