Toxicology III Flashcards

1
Q

T-f– most areas of USA have arsenic levels below .01mg/L. What is considered high?

A

T>1mg is high

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2
Q

What does to much arsenic come from?

A

coal combustion and non-ferrous smelting

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3
Q

What form of Arsenic is the major toxic form?>

A

AsIII[sodium arsenate is example NaAsO2]

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4
Q

What is the main use of arsenic?

A

pesticides[other includes medicine, computer chips, glassware and paints]

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5
Q

What is the main ingredient in ant poison?

A

arsenic trioxide- tasteless…use for homicides

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6
Q

What keeps the high levels of arsenic in fish at check?

A

bound to betaine and is harmless and urinated out

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7
Q

T-F- arsenic is the 3rd most common cause of heavy metal induced death in the USA?

A

False- 2nd

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8
Q

What is the major routes of arsenic uptake?

A

GI and lung

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9
Q

What is arsenic half life=

A

3 days

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10
Q

What are the normal arsenic blood levels?

A

.03-.05 micrograms per dLTotal body burden is 1-10 mg mostly in skin hair and nails

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11
Q

Where is short term accumulation of arsenic?

A

liver, kidney, heart, and lung

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12
Q

Where is the long term storage of arsenic?

A

hair, nails and skin (affinity to keratin, SULFHYDRYL GROUPS!)There is deposition in bones and teeth

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13
Q

What is the major route of arsenic excretion?

A

(sweat, hair, nails, teeth) > feces >urine

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14
Q

What is the mech of arsenic toxicity?

A

accumulates in mitoch. and inhibit mitoch enzymes w/ -SH groups

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15
Q

What are target organs of arsenic toxicity?

A

GI, Kidney, skin,CV, nervous

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16
Q

What is dimercaprol and penicillamine used for?

A

chelation therapy in arsenic toxicity

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17
Q

T-F– arsenic toxicity leads to vasoconstriction?

A

False- dilation

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18
Q

What are mouth symptoms of arsenic?

A

burning lips, garlic breath, constriction of throat.

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19
Q

Review what chronic arsenic exposure does?

A

muscle weaknessperspiration, skin pigmentation, dermatitisnumbness, burning feet soles,vasodilation, heart arrhythmiasischemic gangreneCancerreproductive tox

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20
Q

T-F 13 million live with > 10 micrograms As/L

A

True

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21
Q

Is cadmium bioaccumated?

A

yes, we take up more than we can excrete

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22
Q

Where is cadmium released from?

A

coal burning, Zn missing smelting[used in electroplating, galvanizing, NV-Cd batteries4. color pigment

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23
Q

What is the normal daily uptake of cadmium?

A

10-40 microgram / day

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24
Q

where is most of the body burden for cadmium?

A

kidneys>liver

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25
Q

what haooens in acute oral cadmium exposure?

A

nausea, vomiting, death

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26
Q

What happens in acute respiratory exposure to cadmium?

A

pneumonitis, pulmonary eema, death

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27
Q

What is the treatment for cadmium toxicity?

A

none- support lung function

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28
Q

What happens in chronic chronic lung cadmium exposure? cardiovascular? bone?

A
  1. COPD, BRONCHITIS, EMPHYSEMA2. HYPERTENSION3. PAIN, OSTEOMALACIA (Itai-itai disease japan- Ca metabolism disrupted due to damage)
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29
Q

What type of cancer doe cadmium exposure cause?

A

prostate (and lung, testes, kidney, stomach)

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30
Q

What happens to the kidneys with chronic cadmium exposure?

A

renal tubular disease, proteinuria, Fanconi’s syndrome.

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31
Q

What is the T1/2 of cadmium in humans?

A

10-30 years—> accumulate it with age

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32
Q

Do we have a biological need for lead?

A

no

33
Q

Where does most lead toxicities come from today? 2

A
  1. paint, lead dust in households2. recreation: shooting (and jewelry, stained glass, pottery, paint)
34
Q

how many US children are at risk for lead poisoning?

A

100000, blood lleve > 10 micrograms/dL

35
Q

Is lead problems worse in children?

A

yes their absorption is 41% and retention is 32% whereas adults are just a little over 5%

36
Q

Where is lead sequestered in body?

A

RBCs

37
Q

Doe lead replace Ca in hydroxyapatite in the bone more in children or adults? soft tissue?

A
  1. adults is 90% and children is 70%2. 5%adults, 30%childrne
38
Q

How is lead secreted?

A

urine, milk , fetus

39
Q

can lead pass BBB?

A

yes

40
Q

is lead readily stored, absorbed and mobilized?

A

yes

41
Q

Does led have a cumulation burden?

A

Yes

42
Q

IS there a large margin between population levels and toxicity for lead?

A

No- narrow margin

43
Q

What is t1/2 of lead in soft tissue? bone?

A
  1. 28-36 days2. 15-30 years (also a component of hair and nails as it combines with sulfhydryl groups
44
Q

Acute lead poisoning in children causes what?

A

growth retardation, behavioral and lowered IQ problems

45
Q

Whaat are the 4 keys parts of lead pathophysiology?

A
  1. binds sulfhydryl groups2. disrupts mitoch function3. disrupts Ca dependent intracellular messengers4. Inclusion bodies with a lot of lead
46
Q

why do children have higher blood levels of lead than adults?

A

less goes to bone for storage

47
Q

where does mercury naturally occur?

A

earth crust

48
Q

when is mercury released?

A

coal burning, chlorine processing, waste incineration, and metals

49
Q

What are the estimates for increased in atmospheric Hg due to humans?

A

2-3x or 1.5% per year

50
Q

Does mercury display biomagnification of aquatic ecosystems?

A

yes

51
Q

What form of mercury can bioaccumulate in fish?

A

methylmercury

52
Q

what are CNS side effects of mercury?

A

constriction of vision, hearing loss, sensory disorder, ataxia, central disequilibrium

53
Q

Does mercury damage the kidney? heart? what does it do in prenatal exposure?

A
  1. yes2. yes3. retardation, blindness, cerebral palsy like syndrome
54
Q

What is the body burden of mercury that leads to damage?

A

15-35 gwe intake 3-7 mg /day

55
Q

What is the T1/2 of methyl mercury? what does this lead to?

A

70 days and it leads to bioaccumulation.

56
Q

How many women have more mercury in blood stream than EPA considers safe?

A

8%

57
Q

Review the following recommendations on seafood for women and children

A
  1. do not eat shark, swordfish, king mackerel, or tilefish2. eat up to 12 ounces a week of seafood low in mercury- shrimp, canned light tuna, salmon, pollock, catfish, WHITE TUNA HAS MORE MERCURY THAN CANNED3. check local advisories about the safety of fish caught
58
Q

Where do we get mercury in dentistry?

A

vapors from scrap amalgam are extremely dangerous [can not be discarded as regular trash] Its safety in dental fillings use is very controversial

59
Q

What are 4 key characteristics of POPs?

A

persistent, highly toxic, evaporate and travel long distances hot to cold climates, accumulate in fatty tissue

60
Q

What is trying to eliminate POPs from our environment?

A

Stockholm convention

61
Q

What is dieldrin?

A

halogenated/cyclodiene- used against termites, textile pests, insects in agriculture

62
Q

What is chlordane?

A

halogenated/cyclodiene- used against termites, broad spectrum

63
Q

What is toxaphene?

A

halogenated/cyclodiene- applied to cotton, grains etc. and used against ticks and mites

64
Q

What are the CNS effects of cyclodiene?

A

antagonize GABA r, uncontrolled state of excitation, dizziness, headache, convulsions, jerking

65
Q

What are the GI effects of cylodienes?

A

nause, vomit, induction of liver enzymes C P450s etc

66
Q

Can cyclodienes be absorbed through intact skin? carcinogenic?

A

yesyes

67
Q

What are polychlorinated biphenyls?

A

halogenated industrial compound- used for electrical equipment, prevents overheating, used in papers, sealants, plastics

68
Q

Review the uses of PCBs?

A

capacitors, transformers, plasticizer, surface coatings, sealants CAULK, adhesive cutting oils, pesticide extenders, carbonless paper

69
Q

Where are we exposed to PCBs?

A

1.food (bioaccumulation/biomagnification)2. Air (outdoors, old buildings)

70
Q

When was production of PCBs banned in US?

A

1970

71
Q

When are new PCBs continuously produced?

A

bi products in paint (when green paint isn’t green

72
Q

What is a major PCB effect on the skin?

A

chloracne

73
Q

What are the major PCB effects on the endocrine system?

A

disruption–> anti-estrogen/androgen, disrupts thyroid hormone homeostasis, OBESITY, METABOLIC SYNDROME, T2 diabetes

74
Q

What is a chemical that causes a hormonal imbalance by out competing the body’s natural hormones?

A

endocrine disruptor[causes reproductive and preg. problems, lactation prob, neurodevelopment problems, intellectualproblems in children, etc.]

75
Q

What are PBDEs?

A

polybrominated diphenylethers– bromine flame retardantspenta, octa, deca

76
Q

Where are PBDEs used?

A

electronic equipment, polyurethane foams, hard plastics

77
Q

What country has the highest PBDE in human breast milk?

A

US then Canadafrom flame retardant use in carpets

78
Q

What are PDBEs toxic effects in humans?

A

unknownpossibly carcinogenic[long term exposure has a greater effect than short term toxicity as the build up in your body]

79
Q

How much of the body burden of a nursing mother is thought to be given to their child?

A

1/2!!!!