Pharm Bone Mineral Homeostasis
(101).jpg "Pharm Bone Mineral Homeostasis - Quiz")
Pharmacology students, welcome to today’s quiz on yet another important element of your studies, where we will be discussing pharmaceuticals regarding bone mineral homeostasis. Do you know how these particular drugs work in the body? Answer the questions below and we’ll find out for sure! Good luck!
Questions and Answers
- 1.
DIRECTIONS 1-5 Match each drug affecting bone mineral homeostasis with the appropriate description (each lettered option can be selected only once): This drug can induce osteoclast apoptosis
- A.
Alendronate
- B.
Calcipotriene
- C.
Calcitonin
- D.
Calcitriol
- E.
Calcium
- F.
Cholecalciferol
- G.
Cinacalcet
- H.
Fluoride
- I.
Paricalcitol
- J.
Teriparatide
Correct Answer
A. AlendronateExplanation
Alendronate is a drug that can induce osteoclast apoptosis. This means that it can cause the death of osteoclasts, which are cells responsible for breaking down bone tissue. By inducing osteoclast apoptosis, alendronate helps to slow down bone resorption and maintain bone mineral homeostasis.Rate this question:
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- 2.
DIRECTIONS 1-5 Match each drug affecting bone mineral homeostasis with the appropriate description (each lettered option can be selected only once): This drug is a recombinant PTH 1-34
- A.
Alendronate
- B.
Calcipotriene
- C.
Calcitonin
- D.
Calcitriol
- E.
Calcium
- F.
Cholecalciferol
- G.
Cinacalcet
- H.
Fluoride
- I.
Paricalcitol
- J.
Teriparatide
Correct Answer
J. TeriparatideExplanation
Teriparatide is a recombinant PTH 1-34, meaning it is a synthetic form of parathyroid hormone that contains the first 34 amino acids of the PTH molecule. It is used to treat osteoporosis by stimulating bone formation and increasing bone mineral density.Rate this question:
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- 3.
DIRECTIONS 1-5 Match each drug affecting bone mineral homeostasis with the appropriate description (each lettered option can be selected only once): This drug activates a calcium-sensing receptor on the parathyroid glands
- A.
Alendronate
- B.
Calcipotriene
- C.
Calcitonin
- D.
Calcitriol
- E.
Calcium
- F.
Cholecalciferol
- G.
Cinacalcet
- H.
Fluoride
- I.
Paricalcitol
- J.
Teriparatide
Correct Answer
G. CinacalcetExplanation
Cinacalcet activates a calcium-sensing receptor on the parathyroid glands.Rate this question:
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- 4.
DIRECTIONS 1-5 Match each drug affecting bone mineral homeostasis with the appropriate description (each lettered option can be selected only once): This drug can inhibit the gene expression of PTH
- A.
Alendronate
- B.
Calcipotriene
- C.
Calcitonin
- D.
Calcitriol
- E.
Calcium
- F.
Cholecalciferol
- G.
Cinacalcet
- H.
Fluoride
- I.
Paricalcitol
- J.
Teriparatide
Correct Answer
D. CalcitriolExplanation
Calcitriol is the correct answer because it can inhibit the gene expression of PTH.Rate this question:
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- 5.
DIRECTIONS 1-5 Match each drug affecting bone mineral homeostasis with the appropriate description (each lettered option can be selected only once): This drug is secreted by the parafollicular cells of the thyroid gland
- A.
Alendronate
- B.
Calcipotriene
- C.
Calcitonin
- D.
Calcitriol
- E.
Calcium
- F.
Cholecalciferol
- G.
Cinacalcet
- H.
Fluoride
- I.
Paricalcitol
- J.
Teriparatide
Correct Answer
C. CalcitoninExplanation
Calcitonin is the drug that is secreted by the parafollicular cells of the thyroid gland.Rate this question:
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- 6.
Which of the following actions most likely mediates the therapeutic efficacy of calcitriol in rickets?
- A.
Stimulation of liver hydroxylation of cholecalciferol
- B.
Stimulation of renal alpha1-hydroxylase
- C.
Decreases intestinal phosphate absorption
- D.
Increased intestinal calcium absorption
- E.
Decreased renal phosphate reabsorption
Correct Answer
D. Increased intestinal calcium absorptionExplanation
Intestinal calcium absorption is potently augmented by calcitriol and this seems the main action
that mediates the therapeutic efficacy of calciferols in rickets and in osteomalacia. There is little
evidence that calcitriol directly promotes bone mineralization. Rather is the increased serum
calcium levels that indirectly promotes bone mineralization by decreasing PTH-mediated bone
resorption.
A, B, C, E) (See explanation above)Rate this question:
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- 7.
Which of the following drugs appears to facilitate new bone formation if concomitant calcium supplementation is adequate?
- A.
Phenytoin
- B.
Fluoride
- C.
Thyroxine
- D.
Leuprolide
- E.
Prednisone
Correct Answer
B. FluorideExplanation
Answer: B
If calcium supplementation is adequate, fluoride can increase bone formation and trabecular
bone volume. However the new bone appear to be structurally abnormal and is associated with
an increased incidence of fractures. For these reasons the use of fluoride in the therapy of
osteoporosis remains controversial.
A, C, D, E) All these drugs tend to decrease, not to increase, new bone formation.Rate this question:
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- 8.
A 52-year-old woman was admitted to the hospital because of tetanic muscle spasms and paresthesias following a recent thyroidectomy. Which of the following drugs given IV could rapidly reverse the patient’s symptoms?
- A.
Vitamin D
- B.
Calcitonin
- C.
Sodium phosphate
- D.
Calcium gluconate
- E.
Hydrocortisone
- F.
Alendronate
Correct Answer
D. Calcium gluconateExplanation
Answer: D
The symptoms and the history of the patient indicate that she is suffering from severe
hypocalcemia secondary to hypoparathyroidism, likely due to accidental damage of parathyroid
glands during thyroidectomy. The treatment of severe hypocalcemia can be best accomplished
with slow infusion of calcium gluconate (the preferred calcium salt for Iv therapy because it is
less irritating for veins.
A) Vitamin D can increase calcium levels but its onsets of action is too slow for an emergency
therapy
B, C, E, F) All these drug are actually contraindicated since they decrease serum calcium
levels.Rate this question:
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- 9.
A 49-year-old woman complained to her physician of occasional, severe back pain. Medical history of the patient was significant for mastectomy for breast cancer four years ago, and for an episode of severe angioedema which occurred six month ago after a prophylactic treatment with hepatitis A immune globulin. An x-ray showed diffuse osteoporosis. Which of the following drugs would be most appropriate for this patient?
- A.
Ethynil estradiol
- B.
Calcitonin
- C.
Alendronate
- D.
Sodium fluoride
- E.
Cinacalcet
- F.
Sodium phosphate
Correct Answer
C. AlendronateExplanation
Answer: C
The current options for the pharmacological therapy of osteoporosis are bisphosphonates,
SERMs, calcitonin, PTH (teriparatide) and estrogens. Bisphosphonates are first line therapy
since they preserve bone mass, can decrease vertebral and hip fractures by > 50% and have
low toxicity. Moreover in this patient:
A) Estrogens are contraindicated because of previous breast cancer.
B) Calcitonin is contraindicated because of a previous severe allergic reaction to a protein.
D) Fluoride is not approved for osteoporosis since the results of this treatment are still
controversial.
E, F) These drugs are contraindicated since they decrease serum calcium levels.Rate this question:
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- 10.
A 70-year-old woman suffering from osteoporosis and hypertension, has been treated for the last three years with raloxifene and calcium carbonate (1.5 g daily) for osteoporosis and with hydrochlorothiazide for hypertension. In spite of the therapy, a recent bone mineral density showed a significant decrease in bone mass. Which of the following would be an appropriate change in the treatment plan of this patient?
- A.
To substitute hydrochlorothiazide with propranolol
- B.
To substitute raloxifene with ethinyl-estradiol
- C.
To add calcitonin to the present regimen
- D.
To increase the daily dose of calcium carbonate
- E.
To add prednisone to the present regimen
- F.
To add alendronate to the present regimen
Correct Answer
F. To add alendronate to the present regimenExplanation
Answer: F
Bisphosphonates are first line therapy for osteoporosis, so adding alendronate to the present
regimen is a rational choice, since the therapy failed to prevent the decrease in bone mass.
A) This option is irrational. Hydrochlorotiazide is useful in osteoporosis since it decreases the
renal excretion of calcium.
B) SERMs are today preferred over estrogens for the therapy of osteoporosis since they do not
increase the risk of breast and endometrial cancer.
C) Calcitonin is less effective than bisphosphonates in the therapy of osteoporosis.
D) The dose of calcium taken by the patient is the standard dose for calcium supplementation in
postmenopausal women. It is quite unlikely that a larger dose may add additional benefit.
E) Glucocorticoid are contraindicated in osteoporosis since they increased bone reabsorption.Rate this question:
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- 11.
A 50-year-old man presented to the hospital because of increasingly severe bone pain, which is accentuated at night, headache, fatigue and decreasing auditory acuity. Pasts history of the patient was significant for gastroesophageal reflux disease presently treated with omeprazole. Physical examination revealed skull enlargement, a hobbing gait and anterolateral bowing of the legs with warmth and periosteal tenderness. A X-ray exam showed increased bone density, cortical thickening and bony enlargement. Laboratory results showed alkaline phosphatase of 230 I.U./L (normal 20-90). Which of the following drugs would be appropriate for this patient?
- A.
Calcitonin
- B.
Alendronate
- C.
Calcium carbonate
- D.
Sodium fluoride
- E.
Raloxifene
- F.
Calcitriol
Correct Answer
A. CalcitoninExplanation
Answer: A
The symptoms and signs of the patient indicate that he is most likely affected by Paget’s
disease of bone, a chronic disorder of the adult skeleton in which bone turnover is accelerated
in localized areas. Bisphosphonates are first line agents for this disease. Calcitonin an
alternative to bisphosphonates whin this drugs are contraindicated, as in the present case (see
below).
B) Bisphosphonates are relatively contraindicated in patients with gastrointestinal reflux
disease, esophagitis, gastritis and peptic ulcer.
C, D, E, F) These drugs are useless in Paget’s disease.Rate this question:
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- 12.
A 4-year-old black boy was brought to the emergency room after he fell while playing in the yard. Physical examination revealed only minor skin scratches but an x-ray exam showed 2 rib fractures, a clearly demineralized bone and widening and cupping of metaphyses with exaggerated normal concavity and irregular calcification. Pertinent laboratory values were: calcium 8.3 mg/dL, phosphate 3.2 mg/dL, and a two fold increase in alkaline phosphatase. Which of the following would be an appropriate treatment for this boy?
- A.
Cholecalciferol
- B.
Calcitonin
- C.
Fluoride
- D.
Teriparatide
- E.
Alendronate
Correct Answer
A. CholecalciferolExplanation
Answer: A
The symptoms and signs of the patient together with the lab results suggest that he is suffering
from rickets, a disease that can affect children, more often the black ones, since skin
pigmentation makes ultraviolet irradiation more difficult. Rickets is due to vitamin D deficiency
which in turn causes deficient mineralization of epiphyseal cartilages and osteoid matrix.
Vitamin D deficiency tend to cause hypocalcemia. When this occurs PTH production is
increased. Thus the serum level of calcium is restored to nearly normal by hypophosphatemia
persists and so mineralization of bone is impaired. Cholecalciferol (Vit D3) supplementation with
adequate calcium and phosphate intake is the standard therapy for rickets.
B, C, D , E) (see explanation above)Rate this question:
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- 13.
A 42-year-old man with 25-year history of type 1 diabetes presented for a control visit. His laboratory values were: glucose 190 mg/dL, calcium 11.2 mg/dL, phosphate 5.3 mg/dL, creatinine 4.9 mg/dL. An x-ray exam revealed density changes in the bones that were consistent with renal osteodystrophy. Which of the following drugs should be included in the treatment plan for this patient?
- A.
Alendronate
- B.
Calcitonin
- C.
Paricalcitol
- D.
Sodium fluoride
- E.
Sodium phosphate
Correct Answer
C. ParicalcitolExplanation
Answer: C
The high creatinine levels of the patient point out that the patient was most likely suffering from
chronic renal failure, presumably due to diabetic nephropathy (the most common cause of renal
failure in the U.S.). Chronic renal failure can cause renal osteodystrophy, a term used to
describe collectively all the skeletal changes in chronic renal disease. Renal osteodystrophy is
due to several factors which include loss of calcitriol production because the damaged kidney
cannot activate the renal alpha1-hydroxylase which converts 25(OH) D3 into calcitriol. This
contributes to secondary hyperparathyroidism (remember that calcitriol suppresses PTH gene
expression and secretion) which in turn can cause increased bone resorption. In chronic renal
failure calcitriol should be initiated as long as serum phosphate is not significantly elevated.
Paricalcitol, synthetic analog of calcitriol, is preferred when the secondary hyperparathyroidism
is pronounced, like in the present case (see the high serum calcium levels) because it may
lower PTH levels without significantly increasing serum calcium levels.
A, B, D, E) (see explanation above)Rate this question:
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- 14.
A 46-year-old man presented to the hospital with complains of muscle weakness, fatigue, constipation, nausea and polyuria. Past medical history was unremarkable. Pertinent laboratory values on admission were: calcium of 14.5 mg/dL, phosphate 2.1 mg/dL and immunoreactive parathyroid hormone level of 142 pg/mL (normal 11-54). Which of the following drugs was most likely included in the therapeutic management of the patient?
- A.
Calcitriol
- B.
Hydrochlorothiazide
- C.
Sodium fluoride
- D.
Mannitol
- E.
Calcitonin
Correct Answer
E. CalcitoninExplanation
Answer: E
The symptoms of the patient, together with the high calcium level, the low phosphorus level and
the high parathyroid hormone level are consistent with the diagnosis of primary
hyperparathyroidism. In fact PTH values are elevated in >90% of parathyroid-related causes of
hypercalcemia, undetectable or low in malignancy-related hypercalcemia, and undetectable or
normal in high-bone-turnover causes of hypercalcemia. The approach to medical treatment of
hypercalcemia varies with its severity. Mild hypercalcemia (< 12 mg/dL), can be managed by
hydration. More severe hypercalcemia (13 to 15 mg/dL) must be managed aggressively
because above that level hypercalcemia can be life-threatening and requires emergency
measures. Therefore the more severe the hypercalcemia, the greater the number of combined
therapies that should be used.
The mainstay of treatment, in patients with normal renal function, is to increase renal calcium
excretion with IV saline and furosemide, which inhibits calcium reabsorption in the thick
ascending limb of Henle. Bisphosphonates, which are long-lasting inhibitors of bone resorption,
have become drugs of choice for the antiresorptive treatment of hypercalcemia In addition
calcitonin could be given for its rapid albeit short-lived, blockade of bone resorption. An effect
on serum calcium is observed within 4-6 hours and last 6-10 hours).
A) Calcitriol is contraindicated in this case since it tends to increase serum calcium level. .
B, C) Thiazides are contraindicated since they enhance calcium reabsorption in the distal
convolute tubule. Fluoride stimulate bone formation, but the doses that cause hypocalcemia are
toxic and the drug is not used for this purpose.
D) Potassium sparing diuretics have low efficacy and are contraindicated in this case since they
tend to enhance calcium reabsorption in the distal convolute tubule areRate this question:
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- 15.
A 55-year-old woman complained to her physician of a persistent back pain of 3 days duration. A dual-energy x-ray absorptiometry showed diffuse osteoporosis of the spine and hips. The physician ordered calcium and vit D supplementation and alendronate, 10 mg daily. Which of the following actions most likely mediated the therapeutic effect of alendronate in this patient?
- A.
Stimulation of osteoblast activity
- B.
Stimulation of intestinal calcium absorption
- C.
Inhibition of renal calcium excretion
- D.
Inhibition of osteoclast activity
- E.
Inhibition of renal synthesis of calcitriol
Correct Answer
D. Inhibition of osteoclast activityExplanation
Answer: D
Bisphosphonates, like alendronate, are drugs of choice in osteoporosis. they are incorporated
into the bone matrix and inhibit the activity of osteoclasts in a dose-dependent manner. The
mechanism of this action is still not clear but is presumably related to the stimulation of
osteoclast apoptosis and/or inhibition of some steps of cholesterol biosynthetic pathway that are
important for osteoclast function.
A, B, C, E) (see explanation above)Rate this question:
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- 16.
A 63-year-old woman, suffering from osteoporosis, had been receiving alendronate, and calcium and vit D supplementation for two years, but a recent dual-energy x-ray absorptiometry showed a significant decrease in bone density. The patient history was significant for a femur fracture 8 months ago and a rib fracture one months ago. The physician decided to add teriparatide to the current therapy. Which of the following actions most likely mediated the therapeutic effect of the drug in this patient?
- A.
Stimulation of osteoblast activity
- B.
Stimulation of renal calcium excretion
- C.
Inhibition of renal phosphate excretion
- D.
Inhibition of osteoclast activity
- E.
Inhibition of renal synthesis of calcitriol
Correct Answer
A. Stimulation of osteoblast activityExplanation
Answer: A
Teriparatide is a recombinant PTH 1-34. Eve if PTH can increase both osteoblast and
osteoclast activity, the net effect of excess of PTH is an increase in bone resorption (bone
calcium, phosphate, collagen and proteins decrease). However low and intermittent doses of
PTH increases bone formation (by increasing osteoblast activity) without stimulating bone
resorption. This has lead to the recent approval of teriparatide for the treatment of osteoporosis.
The drug should be reserved should be reserved for those patients with a high risk of fracture,
like in the present case.
B, C) Actually PTH does the opposite.
D) PTH stimulates, not inhibits, osteoclast activity, but this does not occur when therapeutic
doses of teriparatide are given.
E) PTH stimulates, not inhibits, the renal synthesis of calcitriol.Rate this question:
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- 17.
A 47-year-old man presented to his physician complaining of recurring skin lesions most prominent over the scalp, extensor surfaces of elbows and knees, buttock an penis. The man also complained of increasing pain in his left hand and left hip. Physical examination showed oval erythematous plaques covered with thick, silvery, shiny scales. The distal interphalangeal joints of digits two and three of the left hand were swollen and tender. The physician told the patient the diagnosis and ordered a topical drug treatment. Which of the following drugs was most likely prescribed?
- A.
Fludrocortisone
- B.
Calcitonin
- C.
Calcipotriene
- D.
Erythromycin
- E.
Alendronate
Correct Answer
C. CalcipotrieneExplanation
Answer: C
The symptoms and signs of the patient indicate that he was most likely affected by plaque
psoriasis, a common skin disorder that affects 1-5% of the population worldwide. The disease is
diagnosed most often by clinical appearance and distribution of lesions. Arthritis develops in up
to 30% of patients, like in the present case (see the swollen and tender joints). Calcipotriene is
a topical vit D 3 analog which induces normal keratinocyte proliferation and differentiation.
Improvement of psoriasis is generally noted following two weeks of therapy, with continued
improvement for up to 8 weeks of treatment.
A) Glucocorticoids, not mineralocorticoids, are used for psoriasis.
B, D, E) (see explanation above)Rate this question:
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- 18.
A 62-year-old man was admitted to the hospital because of increasing pain in the back and left upper thigh over the past month. The patient also complained that recently he felt drowsy and tired most of the time and urinated very frequently. Past history of the patient was significant for radical prostatectomy for prostate cancer six months ago. Physical examination showed a dehydrated man less alert than normal and slow in his responses. Pertinent laboratory values on admission were: calcium 13.5 mg/L, alkaline phosphatase 204 U/L. An appropriate therapy was started which included an IV infusion of a drug. Which of the following drugs was most likely infused IV?
- A.
Sodium phosphate
- B.
Hydrochlorothiazide
- C.
Pamidronate
- D.
Mannitol
- E.
Calcitriol
- F.
Fludrocortisone
Correct Answer
C. PamidronateExplanation
Answer: C
The symptoms and signs of the patient and the elevated alkaline phosphatase indicated that he
was most likely suffering for hypercalcemia due to bone metastases of prostate cancer.
Rehydration with saline and diuresis with furosemide are the first step of the treatment of severe
hypercalcemia. Bisphosphonates like pamidronate, infused over at least 15 minutes, have been
approved for the acute treatment of hypercalcemia of malignancy.
A) IV sodium phosphate is probably the fastest way to lower serum calcium level, but it is an
hazardous procedure because of the risk involved (sudden hypocalcemia, ectopic calcification,
hypotension, acute renal failure). In light of satisfactory responses to other agents, IV sodium
phosphate cannot be recommended as a mean to treat hypercalcemia Therefore IV phosphate
should be used only after other method of treatment have failed to control hypercalcemia.
B, D, E, F) These drug s are ineffective of contraindicated in case of hypercalcemia.Rate this question:
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- 19.
A 52-year-old homeless man with a 15 year history of alcoholism was brought to the hospital by the police who found him laying on the street. Physical examination showed a disheveled, confused and cachectic man with prominent veins on a very tense abdomen. Pertinent laboratory values on admission were: calcium 5.5 mg/L, ALT 300 U/L (normal 8- 35), AST 255 U/L (normal 8-35). An x-ray disclosed diffuse demineralization of bones. An appropriate therapy was ordered. Which of the following drugs was most likely included in the therapeutic management of this patient?
- A.
Teriparatide
- B.
Cholecalciferol
- C.
Sodium fluoride
- D.
Calcitriol
- E.
Calcipotriene
Correct Answer
D. CalcitriolExplanation
Answer: D
The symptoms, the lab results and the history of the patient indicate that he was most likely
suffering from alcoholic cirrhosis. The bone demineralization and the low calcium levels suggest
that the diffuse liver disease caused an impaired synthesis of 25(OH)D with the final outcome of
osteomalacia. Calcitriol is the most effective agent for hypocalcemia in a patient with impaired
liver function since it bypass the impaired synthesis of the agent.
A) Patients with hypocalcemia have already an increased production of PTH, so teriparatide can
add very little to the therapy.
B) Vit D3 is not effective because the liver cannot provide the 25 hydroxylation.
C, E )(see explanation above)Rate this question:
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- 20.
A 56-year-old woman complained to her physician of frequent heartburn and pain in the substernal region. The woman, recently diagnosed with postmenopausal osteoporosis, started an appropriate therapy two weeks previously. Which of the following drugs most likely caused the patient’s symptoms?
- A.
Prednisone
- B.
Calcitonin
- C.
Raloxifene
- D.
Teriparatide
- E.
Alendronate
Correct Answer
E. AlendronateExplanation
Answer: E
When administered by oral route bisphosphonates (mainly alendronate)can cause frequently
esophageal and gastric irritation. Because of this patients are often instructed to take the
medication early in the morning on an empty stomach with a large glass of water and then to
stay upright for 30 minutes in order to reduce the chance of esophageal irritation.
A) Glucocorticoids can cause gastric irritation but they are contraindicated in osteoporosis.
B, C, D) These drugs are used in case of osteoporosis but their risk of esophageal and gastric irritation is very low.Rate this question:
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Oct 08, 2024Quiz Edited by
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Jun 24, 2012Quiz Created by
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