CD23 Metals

Question 1

Why is beryllium unique among metals?
A. it causes injury in skin and lung through an immune mechanism
B. it is not excreted in the urine following uptake in lymph
C. it cannot be absorbed orally
D. it is readily absorbed through the skin

Answer 1

A. it causes injury in skin and lung through an immune mechanism

Explanation and Reference:
Beryllium causes an inflammatory immune reaction. C&D 8th, pp. 989-999

Question 2

What substance is the most effective agent for treating acute mild inorganic mercury intoxication?
A. British Anti-Lewisite (BAL)
B. hydrochlorothiazide
C. intravenous glucose
D. aminophylline

Answer 2

A. British Anti-Lewisite (BAL)

Explanation and Reference:
The chelating agent BAL, also called as dimercaprol, is effective with inorganic poisoning. C&D 8th,
p. 999

Question 3

What effect is clearly indicative of exposure to nickel?
A. nephropathy
B. Menkes disease
C. contact dermatitis
D. encephalopathy

Answer 3

C. contact dermatitis

Explanation and Reference:
Nickel-induced contact dermatitis is found in 10-20% of the population. C&D 8th, p. 1000

Question 4

What primary organ system is affected after consumption of grain treated with mercurial (organic) fungicides?
A. respiratory
B. hepatic
C. renal
D. nervous

Answer 4

D. nervous

Explanation and Reference:
The nervous system is the target for organic mercury compounds. C&D 8th, p. 999.

Question 5

What characteristic clinical sign is associated with industrial exposure to vanadium pentoxide dust?
A. non-fibrotic pneumoconiosis
B. greenish-black discoloration of the tongue
C. glucosuria
D. gastroenteritis, polyneuropathy, and alopecia

Answer 5

B. greenish-black discoloration of the tongue

Explanation and Reference:
Glucosuria is a common sign of uranium-related renal toxicity; non-fibrotic pneumoconiosis is commonly assocxiated with chornic exposure to tin; gastroenteritis, polyneuropathy, and alopecia are classic signs of thallium poisoning. The blue-green discoloration of the tongue is very characteristic of Vanadium exposure in industrial settings. C&D 8th, pp. 1018-1021.

Question 6

What oxidation state of arsenic is considered to be the most toxic?
A. divalent
B. pentavelent
C. trivalent
D. hexavalent

Answer 6

C. trivalent

Explanation and Reference:
Trivalent forms of As are more toxic compared to pentavalent forms. C&D, 8th ed., 986-989.

Question 7

What is the preferred treatment of cyanide poisoning?
A. sodium nitrite
B. atropine followed by 2-PAM
C. dimercaprol and pralidoxime
D. calcium disodium edetate (EDTA)

Answer 7

A. sodium nitrite

Explanation and Reference:
Nitrite converts hemoglobin to methemoglobin which in turn competes effectively for CN with the mitochondrial cytochrome oxidase complex. Hayes 6th p. 22.

Question 8

Cadmium may accumulate in the kidney without toxic effect for what reason?
A. cadmium decreases the excretion of urinary proteins
B. cadmium binds to metallothionein and forms a metal-protein complex
C. cadmium increases renal tubular absorption of phosphate
D. cadmium produces oliguria

Answer 8

B. cadmium binds to metallothionein and forms a metal-protein complex

Explanation and Reference:
Cadmium induces metallothionine with subsequestration of cadmium as Cd-MT complex. C&D 9th p. 783`

Question 9

What is the primary mechanism of action for mercury-induced non-specific cell injury or cell death?
A. cellular mimicry and replacement of divalent zinc in metalloenzymes
B. formation of DNA adducts or DNA-protein crosslinks
C. uncoupling of mitochondrial oxidative phosphorylation
D. high-affinity binding of divalent mercury to sulfhydryl groups of proteins

Answer 9

D. high-affinity binding of divalent mercury to sulfhydryl groups of proteins

Explanation and Reference:
Oxidative stress plays a significant role in Hg toxicity. C&D 9th p. 1129

Question 10

What elements are essential nutrients?
A. iron, nickel, copper
B. zinc, copper, cobalt
C. vanadium, thallium, manganese
D. copper, beryllium, selenium

Answer 10

B. zinc, copper, cobalt

Explanation and Reference:
Cobalt, copper, iron, magnesium, manganese, molybdenum, selenium, zinc, and contraversially, trivalent chromium are essential metals. Nickel, beryllium, thallium, and vanadium are not essential nutrients. C&D 9th, pp. 1131-1140

Question 11

The ability of metallothionein to bind metallic cations is a function of its high content of what molecule?
A. methionine
B. cysteine
C. lysine
D. N-acetylcysteine

Answer 11

B. cysteine

Explanation and Reference:
Metallothioneins (MTs) include any inducible low molecular weight cytosolic protein with highly conserved cysteines and numerous cysteinyl thiol groups allowing them to bind to a diverse group of metals. Hayes 6th, p. 2095; C&D 9th p. 1111-1112.

Question 12

Contact hypersensitivity reactions are commonly associated with direct and prolonged contact with what element?
A. nickel
B. lithium
C. iron
D. lead

Answer 12

A. nickel

Explanation and Reference:
Nickel has been reported to elicit contact urticaria C&D 9th p 966-967

Question 13

Iron (Fe) is an essential mineral but overdoses result in damage to hepatocytes in which region of the liver?
A. midzonal
B. periportal
C. centrilobular
D. bile canuliculi

Answer 13

B. periportal

Explanation and Reference:
The zone 1 hepatocytes both preferentially accumulate iron and since they are closer to the oxygen- rich blood entering the sinusoid and the higher oxygen concentration faciliates lipid peroxidation.
C&D 8th, p. 650, Table 13-3