Part 2: Descriptive Toxicology: Environmental, Clinical, Nonclinical, and Forensic Investigations

Question 1

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

Answer 1

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

Question 2

Exposure to ethylene glycol monomethyl ether (EGME) and/or one of its metabolites, methoxyacetic acid (MAA), will induce testicular damage in rats by primarily affecting what cell types?
A. Leydig cell
B. Cowper’s gland
C. Sertoli cell
D. myoepithelial peritubular cell

Answer 2

Answer: C
Explanation and Reference:
Mechanistic studies have shown the Sertoli cell to be affected which disrupts spermatocyte maturation. C&D 8th, pp. 1078-1079

Question 3

What organ systems are classic targets of acute and chronic carbon disulfide exposure?
A. upper and lower respiratory system
B. skeletal and cardiac muscle
C. central and peripheral nervous system
D. vascular and lymphatic system

Answer 3

Answer: C
Explanation and Reference:
Exposure to CS2 (dithiocarbonic anhydride) affects a number of organ systems. The effects are prominent in central and periphernal nervous, system, retina, and as an atherogenic agent. Classic lesions of CS2 exposure are found in both the peripheral and central nervous systems. There is evidence that CS2 also modifies low density lipoprotein and enhances arterial fatty deposits.
Surprisingly, the respiratory system is not a target for CS2. C&D 8th, p. 1086-1087.

Question 4

4. The Local Lymph Node Assay (LLNA) is an internationally approved method to detect what pathogenic response?
   A. induction of carcinogenesis by a chemical applied to the skin
   B. elicitation of sensitivity to a chemical applied to the skin
   C. elicitation of carcinogenesis by a chemical applied intratracheally
   D. induction of allergic contact dermatiti

Answer 4

Answer: D
Explanation and Reference:
The LLNA is a refinement of the classic GP-MAX and Buehler assys for allergic contact dermatitis. Whereas the classsic assays measure both induction and elicitation of skin sensitization, the LLNA only measures induction, resulting in a shorter assay. The LLNA is now the recommended method for determining allergic contact dermatitis potential of chemicals. Hayes 6th, pp. 1100-1102.

Question 5

5. Acetaminophen hepatotoxicity requires what intermediate step?
   A. the toxicity does not depend on metabolism of acetaminophen
   B. interaction with sodium nitrosulfate
   C. binding to cellular macromolecules
   D. inhibition by ethanol co-administratio

Answer 5

Answer: C
Explanation and Reference:
The toxic metabolite of acetaminophen binds to glutathione; when cellular glutathione is depleted, the metabolite binds to cellular macromolecules, particularly proteins. C&D, 8th, pp. 651.

Question 6

Several inhibitors of cyclooxygenase-2 (COX-2) have been removed from the market due to what potential type of toxicity?
A. hepatic
B. neurologic
C. cardiovascular
D. rena

Answer 6

Answer: C
Explanation and Reference:
These compounds may cause hypertension which elevates the risk of heart attack and stroke. C&D, 8th, pp. 819-824.

Question 7

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. aminophyllin

Answer 7

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

Question 8

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 8

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

Question 9

Organic solvents are a group of compounds that have what characteristics?
A. low vapor pressure at room temperature
B. high molecular weight side chains including -OH groups
C. cannot be absorbed across the skin in significant amounts
D. common effects on the central nervous system

Answer 9

Answer: D
Explanation and Reference:
CNS effects are common to solvents. C&D 8th, pp. 1031-1036.

Question 10

The “Elixir Sulfanilamide” tragedy, resulted in the passage of the Copeland Bill in 1938 due to what environmental effects?
A. diethylene glycol induced acute kidney failure
B. ethanol induced liver toxicity and blindness
C. diethylene glycol induced acute liver failure
D. polyethylene glycol induced renal failure

Answer 10

Answer: A
Explanation and Reference:
The drug was found to be more soluble in diethylene glycol and sold as that formulation, but diethylene glycol caused acute renal failure in several patients. C&D 9th, p. 12

Question 11

Acute poisoning by malathion is recognized by what group of effects?
A. acute renal failure followed by lacrimation and defecation
B. burning and discoloration of the mucous membranes
C. salivation, lacrimation, headache, and dizziness
D. pulmonary fluid accumulation and respiratory failure

Answer 11

Answer: C
Explanation and Reference:
Malathion is an OP with symptoms as described in C&D 8th, p. 941, Table 22-9

Question 12

For most systemically administered drugs, what measure is used to convert the animal dose to a human equivalent dose (HED)?
A. mg/m2
B. Cmax
C. AUC
D. mg/kg

Answer 12

Answer: A
Explanation and Reference:
mg/m2 is the recommended conversion, the other values should be adjusted depending on toxicity observed in animal studies. FDA Guidance (2010) M3(R2), Table 3

Question 13

Organophosphates and carbamates exhibit which characteristics?
A. they act by a common mechanism, but arise from two distinctively different chemical classes
B. they do not undergo extensive biotransformation in most species
C. their binding to the acetylcholinesterase is irreversible except in rare instances
D. they were first developed as warfare agents during World War

Answer 13

Answer: A
Explanation and Reference:
Organophosphates and carbamates both inhibit acetylcholinesterase. C&D 8th, pp. 939-947

Question 14

Based on your knowledge of toxicology, what is the general line of treatment for scombrotoxicosis?
A. induced emesis with apomorphine
B. intramuscular injection of cortisone
C. intravenous injection of sodium nitrite
D. enteral or parenteral administration of antihistamine

Answer 14

Answer: D
Explanation and Reference:
Histidine occurs naturally in many fish, and at temperatures above 60°F on air contact it is converted to the biogenic amine histamine via the enzyme histidine decarboxylase produced by enteric bacteria. Histamine is not destroyed by normal cooking temperatures, so even people eating properly cooked fish can be affected. Hayes 6th, pp. 662-663

Question 15

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

Answer 15

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

Question 16

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 16

Answer: B
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 17

What is the basis for the use of ethanol as an antidote for accidental oral methanol poisoning?
A. it binds with methanol and increases urinary excretion
B. it competitively inhibits the metabolism of methanol
C. it increases metabolism of methanol to formaldehyde
D. it chemically alters methanol to formate

Answer 17

Answer: B
Explanation and Reference:
Inhibits alcohol dehydrogenase blocking the formation of formic acid. Folate is also given to enhance efficiency of formate oxidation. C&D 7th, pp 1012-1014; C&D 8th, p. 1073

Question 18

What is the recommended treatment for methanol intoxication?
A. intravenous hemoperfusion
B. forced diuresis with emetic.
C. inhibition of alcohol dehydrogenase by 4-methylpyrazole (fomepizole)
D. inhibition of aldehyde dehydrogenase by disulfiram

Answer 18

Answer: C
Explanation and Reference:
Metabolic blockade by ethanol or 4-methylpryazole is first line treatment. Sodium bicarbonate by i.v can by used to correct metabolic acidosis and folate can be used to enhance formate excretion. C&D 8th p. 1073.

Question 19

What is the most effective treatment for mammalian organophosphate (OP) toxicity?
A. atropine
B. diazepam
C. 2-PAM
D. epinephrine

Answer 19

Answer: A
Explanation and Reference:
As a muscarinic receptor antagonist, atropine prevents the action of accumulating acetylcholine on cholinergic receptors. The administration of pralidoxime (2-PAM) early after OP exposure can help prevent acetylcholinesterase aging. Diazepam may be used for relieving anxiety, muscle fasciculations, and convulsions. C&D 7th, p.891; C&D 8th p. 941.

Question 20

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 20

Answer: A
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 21

In the field of epidemiology, what parameter is defined as the risk difference between exposed and unexposed groups, divided by the risk in the exposed group?
A. attributable risk
B. relative risk
C. proportional mortality ratio
D. absolute risk

Answer 21

Answer: A
Explanation and Reference:
Absolute risk is more a concept than a calculation and revolves around the question whether a specific disease among an exposed group is greater than the absolute risk of that same disease in an unexposed group. Relative risk (RR) is the ratio of incidence rates in two different groups (e.g., exposed versus unexposed). The proportional mortality ratio (PMR) is not to be confused with RR or absolute risk. This is the number of deaths within a population due to a specific disease or cause divided by the total number of deaths in the population during a time period such as a year. The correct answer (A) is attributable risk where rate ratios and rate differences are based on exposure status. The attributable risk gives a better indication of causality than the other indices. Hayes 6th, p 535.

Question 22

What are the classic clinical features of the anticholinergic toxidrome?
A. mydriasis, hyperalert, increased pulse, increased blood pressure
B. miosis, decreased pulse, altered mental status
C. miosis, decreased level of consciousness, decreased pulse, no change in blood pressure
D. mydriasis, altered mental status, increased pulse, no change in blood pressure

Answer 22

Answer: D
Explanation and Reference:
Anticholinergic syndrome is produced by the inhibition of cholinergic neurotransmission at muscarinic receptor sites. Signs include ileus, urine retention, tachycardia, hypertension, confusion, fever, dry skin, mydriasis. A number of plant exposures can produce this syndrome through the action of natural constituents such as atropine and scopolomine. Hayes 6th, p. 961.

Question 23

What is the first step in treating a suspected poisoning victim?
A. submission of blood and urine for immediate analysis
B. administration of the antidote
C. prevention of further toxin absorption
D. stabilization of the patient

Answer 23

Answer: D
Explanation and Reference:
First step is almost always stabilization of the patient (breathing, pulse, etc.). C&D 9th, p. 1533

Question 24

What is a major limitation of epidemiology studies?
A. exposure conditions are unrealistic
B. exposure is not well-defined or controlled
C. effects are measured in humans
D. interactive effects among individual chemicals cannot be measured

Answer 24

Answer: B
Explanation and Reference:
Exposure is often not well defined and controlled in epidemiological studies especially environmental. C&D 9th, p. 136

Question 25

25. Data from standard toxicology studies conducted with pharmaceuticals are evaluated for signs of immunotoxic potential. According to ICH S8, what is evidence of immunotoxic potential? A. alterations in immune system organ weights and/or histology B. decreased incidence of infections C. hematological changes such as erythrocytopenia/erythrocytosis D. mild thymic atrophy accompanied by decreased food consumption and a significant decrease in body weight gain

Answer 25

Answer: A Explanation and Reference: Changes in the hematology panel would not suggest mild changes in the immune system; therefore, it would be a very insensitive high-level index of immunotoxicity. Similarly, mild thymic atrophy could be caused by many things including stress. In animals showing decreased food consumption and body weight, thymic atrophy would be a common finding and not indicative of immunotoxicity. Finally an increased incidence of infections would suggest immunocompromise; however, a decreased incidence of infections has little meaning in a preclinical safety study. The correct answer (B), changes in immune system organ weights and histology, would be routinely measured in a preclinical study and would require further immune system testing. ICH S8 Harmonized Tripartite Guideline Immunotoxicity Studies for Human Pharmaceuticals S8, 15 September 2005, Section 2.1.1 page 3.

Question 26

26. A 16-year-old harvester was brought to the emergency room after working for 2 days in rain-soaked tobacco fields. He complained of vomiting, weakness, dizziness, headache, and dyspnea. His vital signs were a heart rate of 120 beats/minute, blood pressure A. organophosphates B. pyrethrin C. nicotine D. paraquat

Answer 26

Answer: C Explanation and Reference: Green tobacco sickness (GTS) is an illness resulting from dermal exposure to dissolved nicotine from wet tobacco leaves; it is characterized by nausea, vomiting, weakness, and dizziness and sometimes fluctuations in blood pressure or heart rate Green Leaf Tobacco Sickness. C&D 9th, p. 858

Question 27

27. Repeated occupational exposure to toluene diisocyanates are a common cause of what condition? A. fibrotic lung disease B. asthma C. hemangiosarcoma D. peripheral neuropathy

Answer 27

Answer: B Explanation and Reference: Some individuals develop an allergic reaction to toluene diisocyanates following inhalation exposure. Re-exposure to the chemical can cause severe asthma symptoms that can be immediate or delayed for an hour or more. However this usually happens in the workplace and the general public is not expected to be exposed to such levels. Long-term inhalation exposure can also cause lung damage. C&D 9th, p. 689-690

Question 28

28. What prospective epidemiological study design assesses development of disease in a population of known exposure? A. cross-sectional B. case-control C. cohort D. cross-over

Answer 28

Answer: C Explanation and Reference: Case Control - two source populations; assumption that non-cases are representative of the source population of cases; Correct Answer: Cohort uses exposed and non-exposed populations; Cross over - longitudinal study in which subjects receive a sequence of different treatments (or exposures); Cross-sectional - where only ONE set of observations is collected for every unit in the study, at a certain point in time, disregarding the length of time of the study as a whole; C&D 9th, pp. 136-137

Question 29

29. What is the "prevalence" of a disease? A. the incidence rate B. the number of cases at a specified moment of time C. the rate at which new cases develop D. the cure rate

Answer 29

Answer: B Explanation and Reference: Prevalence is what is observed at a single point in chronological or biological time. Hayes 6th, p. 531

Question 30

30. What type of epidemiological study is used to compare disease prevalence or health status between groups of workers classified according to job titles, work site, or exposure status in present time? A. case-control B. cross-sectional C. retrospective cohort D. prospective cohort

Answer 30

Answer: B Explanation and Reference: Cohort studies are always prospective and report out incidence. Case-control studies are retrospective and report out fractional percent of disease vs non-disease subjects. Only the cross- sectional study design reports out prevalence- where only ONE set of observations is collected for every unit in the study, at a certain point in time, disregarding the length of time of the study as a whole. C&D 8th, p. 131.

Question 31

31. An individual has taken an overdose of atropine. What is the appropriate treatment/antidote? A. methyl-atropine, another competitive acetylcholine antagonist B. nicotine, a nicotinic antagonist C. physostigmine, an acetylcholinesterase inhibitor D. succinylcholine, a nicotine antagonist

Answer 31

Answer: C Explanation and Reference: Physostigmine, given as an atropine antidote by slow intravenous injection of 1 to 4 mg (0.5 to 1.0 mg in children), rapidly abolishes delirium and coma caused by large doses of atropine. Since physostigmine is rapidly destroyed, the patient may again lapse into coma after one to two hours, and repeated doses may be required. Artificial respiration with oxygen may be necessary. Ice bags and alcohol sponges help to reduce fever, especially in children. C&D 9th, p. 1064

Question 32

32. What is the most frequently encountered xenobiotic among emergency toxicology cases? A. ethanol B. methamphetamine C. painkillers D. heroine

Answer 32

Answer: A Explanation and Reference: Nearly 88,000 people die annually in the United States as a direct or indirect exposure to alcohol. C&D 9th, p. 1525

Question 33

33. What testicular tumor is a frequently occurring endocrine tumor in rodent chronic toxicity/carcinogenicity studies (i.e., observed at a background incidence in the F344 rat of 70-90%)? A. granulosa cell tumor B. dendritic cell tumor C. Leydig cell tumor D. Sertoli cell tumor

Answer 33

Answer: C Explanation and Reference: Control F344 rats have an extremely high spontaneous incidence of Leydig cell tumors. Therefore, these tumors are believed to be irrelevant to men. C&D, 8th ed., pp. 1055-1056.

Question 34

34. What is a common observation in rodent models when thyroid hormone homeostasis is disrupted? A. increased incidence of thyroid tumors B. disruption in body temperature maintenance C. reductions in overall animal body weight D. Due to reserve capacity of the thyroid, hormone disruption does not result in observable toxicity.

Answer 34

Answer: A Explanation and Reference: A reduction of thyroid hormone concentrations and increased thyroid-stimulating hormones have shown to induce neoplasia in the rodent thyroid. C&D 8th, pp. 412-413.

Question 35

35. Delayed Type Hypersensitivity is associated with what characteristic? A. chemical presentation to Langerhans cells B. absence of inflammation C. clonal expansion of B cells D. cell-mediated response

Answer 35

Answer: D Explanation and Reference: Delayed Type Hypersensitivity (DTH) is cell, not antibody mediated. C&D 9th, p. 1038-1040

Question 36

36. What would produce a level of great concern for the development of human cancer, based on preclinical laboratory and animal data? A. toxicity associated tumors B. not genotoxic C. a finding of tumor site concordance between species D. single species effect

Answer 36

Answer: C Explanation and Reference: Examples shows a weight of evidence approach between species to extrapolate to humans. C&D 9th, p. 478

Question 37

37. Different cell populations of the mammalian testes exhibit different thresholds of sensitivity to different toxicants. What region/cell type in the testes is generally considered to be the most sensitive to chemical insult? A. rete testis B. germ cells C. the seminiferous epithelium D. Leydig cells

Answer 37

Answer: B Explanation and Reference: Germ cells are typically the most sensitive. C&D 8th,pp. 874-878.

Question 38

38. Where is inhibin, a regulator of FSH production and a biomarker for male reproductive damage, secreted/produced from? A. Leydig cells B. spermatogonia C. Sertoli cells D. epididymides

Answer 38

Answer: C Explanation and Reference: Inhibin is produced by Sertoli cells in the seminiferous tubules, not in the spermatogonia or epididymides. Leydig cells are the sites of testosterone biosynthesis. Hayes 6th, p. 1621.

Question 39

39. What is the fate of very water-soluble gases in the respiratory system? A. trapped by bronchiolar mucus and removed by the mucociliary escalator B. transported directly to the deep lung and absorbed into the general circulation C. absorbed into the systemic circulation through the capillaries of the nose D. transported directly to the deep lung where they react chemically with Type II pneumocytes

Answer 39

Answer: A Explanation and Reference: Highly water-soluble gases are filtered through the nasal turbinates and are efficiencly absorpbed from that site. Such gas species rarely make it to the respiratory sections of lung. C&D 8th, p. 692

Question 40

40. What common characteristic is shared by all four types of hypersensitivity responses? A. involves formation of specific immunoglobulin molecules B. requires prior exposure to an antigen C. involves activation of mast cells in respiratory bronchioles D. are cell-mediated responses that are delayed

Answer 40

Answer: B Explanation and Reference: One characteristic common to all four types of hypersensitivity reactions is the necessity of prior exposure leading to sensitization in order to eliciti a reaction upon subsequent challenge. C&D 9th edition, page 646

Question 41

41. What pair of immune-mediated hypersensitivity reactions to chemicals is the most frequently reported in humans? A. Type I and Type III B. Type IV and Type I C. Type II and Type IV D. Type III and Type IV

Answer 41

Answer: B Explanation and Reference: Mostly manifested as contact and respiratory sensitization, respectively. C&D 9th, p. 660

Question 42

42. Which ocular structure is most often affected following systemic long-term or high dose use of corticosteroids in humans? A. cornea B. lens C. retina D. iris

Answer 42

Answer: B Explanation and Reference: Long-term systemic use of corticosteriouds is implicated in cataracts. C&D 9th edition, page 880

Question 43

43. Exposure of rats to a naphthalene-derived pesticide resulted in a loss of circulating erythrocytes that was accompanied by reticulocytosis and hemoglobinuria. No pathological changes were observed in the bone marrow; however, spleens were found to be enla A. anemia due to iron deficiency B. mechanical (march) hemoglobinuria C. aplastic anemia D. non-immune hemolytic anemia

Answer 43

Answer: D Explanation and Reference: The data in this case suggest mature red blood cell destruction, possibly caused by xenobiotic production of reactive oxygen species (explaining the decreased reduced glutathione). The reticuloytosis suggests that the bone marrow is intact and producing new red cells, so iron-deficient and aplastic anemias are ruled out. There is no history of mechanical stress. A chemically induced, non-immune hemolytic anemia is the most likely diagnosis given the history and clinical data. C&D 9th, p. 602-603

Question 44

44. Most inhaled particles with a mean aerodynamic diameter of 1 micron are deposited in what respiratory region? A. alveoli B. nasopharyngeal region C. bronchioles D. bifurcations of major bronchi

Answer 44

Answer: A Explanation and Reference: Particles of ~1 μm are typically deposited in the alveolar region. C&D 9th, p. 795

Question 45

45. What is the primary factor that determines the region of the respiratory tract where a particle or an aerosol will be deposited? A. size of the particle B. chemical composition of the particle C. particle shape D. respiratory rate

Answer 45

Answer: A Explanation and Reference: The efficiency of particle deposition in various regions of the respiratory tract depends mainly on particle size. C&D 9th, p. 803

Question 46

Type III hypersensitivity reactions are mediated by what combination of immunoglobulin or cell type? A. IgG and antigen B. IgE and macrophages C. T lymphocytes and macrophages D. IgE and mast cells

Answer 46

Answer: A Explanation and Reference: Type III Hypersensitivity involve the IgG against soluble antigen in the serum. C&D 9th, p. 647

Question 47

47. What ocular structure is the target of chronic, high-dose tamoxifen therapy? A. cornea B. lens C. retina D. conjunctiva

Answer 47

Answer: C Explanation and Reference: Tamoxifen, a nonsteroidal antiestrogenic drug that competes with estrogen for its receptor sites and used for treatment of metastatic breast carcinoma, causes retinopathy following chronic high-dose therapy. C&D, 9th ed. p. 892

Question 48

48. What toxico-pathological feature characterizes hepatic steatosis? A. accumulation of smooth endoplasmic reticulum in hepatocytes B. accumulation of lipids in hepatocytes C. hepatocyte nuclear lysis D. retention of bilirubin

Answer 48

Answer: B Explanation and Reference: Steatosis or "fatty liver" is the accumulation of lipids, primarily triglycerides, within the hepatocytes. Hayes, 6th ed., pp. 1447-1448; C&D 9th pp. 727-728.

Question 49

49. What toxic food contaminant is a major by-product of cooking at high-temperatures? A. heterocyclic amine B. botulinum toxin C. fumonisin D. trichothecene

Answer 49

Answer: A Explanation and Reference: Heterocyclic amines are formed as a result of high-temperature cooking of foods high in proteins and carbohydrates. C&D 9th, p1350

Question 50

50. The presence of melamine as an adulterant in infant formula and pet food was associated with mortalities in human infants and pets in the mid-2000s. What was the mechanism of action underlying melamine-related toxicity? A. acute hepatic toxicity B. acute cardiac toxicity C. blockade of mitochondrial oxidative phosphorylation D. formation of crystaline precipitates in renal tubules

Answer 50

Answer: D Explanation and Reference: Melamine often in combination with cyanuric acid has been associated with renal failure in children and companion animals. The mechanism of toxicity is crystal formation in the tubules and bladder. The source of melamine was its illegal addition to increase nitrogen content in order deceive test inspections for protein content. Torres and Bobst, Toxicological Risk Assessment for Beginners, p. 23.

Question 51

51. Ethanol, retinoids, valproic acid, and the angiotensin converting enzyme (ACE) inhibitors share what common toxicological characteristic? A. cause liver toxicity B. have central nervous system effects C. are human developmental toxicants D. lower blood pressure

Answer 51

Answer: C Explanation and Reference: These are known to cause craniofacial malformations, heart and limb malformations oligohydramnios, fetal growth retardation, pulmonary hypoplasia, joint contractures, hypocalvaria, neonatal renal failure, hypotension, and death. C&D 9th, p. 550, 551,

Question 52

52. What adverse effect related to low level exposure to lead in blood is of greatest public health concern ? A. anemia B. proximal tubular nephropathy in the elderly C. cognitive delays and behavioral changes in children D. encephalopathy

Answer 52

Answer: C Explanation and Reference: Neurological changes in the developing brain are the most sensitive and greatest concern from lead exposure. C&D 9th, p 863

Question 53

53. John really enjoys grapefruit juice and consumes several large glasses per day. He recently started taking a new medication and has begun to experience severe muscle aches. Lab tests have revealed elevated creatine kinase and alanine aminotransferase le A. acetaminophen B. atorvastatin C. naproxen D. cyclosporine

Answer 53

Answer: B Explanation and Reference: Components in grapefruit juice inhibit intestinal CYP3A4 which blocks the metabolism of statins such as atorvastatin. C&D 9th, p 290-291, 307-310

Question 54

54. Why might epidemiological data be considered to be preferable for dose-response modeling in certain cases? A. by using biomarkers, the doses associated with effects can be more precisely defined, thereby avoiding the need for external dose estimation B. it is possible to model dose-response relationships directly in humans, thereby avoiding concern for species differences C. the impact of exposure over a lifetime can be more easily examined than in a multiyear laboratory animal study D. the causal relationship between dose and response can be easily established

Answer 54

Answer: B Explanation and Reference: Epidemiology studies do monitor dose-response relationships in humans by directly evaluating human data on exposure and incidence. Confounding factors such as life style, multiple exposures and robust exposure estimates impact the outcome. C&D 9th, p 136

Question 55

55. Two contractors hired by a health club to refinish the racquetball court floors were using a varnish stripper to remove the old finish. They were found dead on the court after the management requested they seal the air vents due to patron complaints about A. myocardial sensitization due to the use of n-hexane B. narcosis and chemical hypoxia from the use of methylene chloride C. central nervous system depression from carbon disulfide exposure D. pulmonary edema from the use of methyl n-butyl ketone

Answer 55

Answer: B Explanation and Reference: Metabolism of methylene chloride releases carbon monoxide resulting in carboxyhemoglobin and tissue hypoxia. C&D 7th, p. 1003

Question 56

56. Cutaneous paresthesia is the primary adverse effect from occupational exposure to what pesticide? A. deltamethrin B. parathion C. carbaryl D. dichlorodiphenyltrichloroethane (DDT)

Answer 56

Answer: A Explanation and Reference: Metabolism of methylene chloride releases carbon monoxide resulting in carboxyhemoglobin and tissue hypoxia. C&D 9th, 1191