Clinical Correlates 8 Products from Amino Acids Flashcards Preview

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Flashcards in Clinical Correlates 8 Products from Amino Acids Deck (19):
1

The amount of creatinine excreted per day depends on _____ and kidney function and is constant at about 15 mmol for the average person. In cases of kidney failure, creatinine rises, as does the ____ __.

body muscle mass
blood urea nitrogen (BUN)

2

___ is the drug that is commonly ingested at an overdose level. Glutathione plays a major role in detoxifying this potential hepatotoxic and lethal agent. As stores of GSH dwindle, the patient moves from malaise and vomiting to jaundice, ___ ____, and finally death. _____ (NAC) is a medication that replenishes levels of GSH during acetaminophen toxicity.

Acetaminophen
gastrointestinal bleeding, encephalopathy
N-Acetylcysteine

3

Numerous pharmacologic agents known as ___ (i.e., nitroglycerine, nitroprusside, and isosorbide dinitrate) release NO once they are in the bloodstream and are used in the control of blood pressure in select patients.

nitrates

4

GABA promotes ____ ___ by promoting entry of chloride into the neuron. Numerous pharmacologic agents (i.e., benzodiazepines, topiramate, lamotrigine, and tiagabine) ___ GABA activity in the treatment of seizures and other hyperspastic disorders.

neuron inhibition
stimulate

5

Histidine binds to __ receptors in the stomach, stimulating the release of gastric acid. Pharmacologic blockers of H1 receptors are used in the treatment of gastric reflux. H2 receptors are located on basophils and stimulate their degranulation during the allergic response. H2 receptor blockers are used to treat ___ conditions.

H1
allergic

6

Serotonin is an important stimulatory neurotransmitter involved in mood. Selective serotonin reuptake inhibitors (SSRIs) promote serotonin’s actions and are first-line agents in the treatment of ___.

depression

7

___ ___ overproduce the neurotransmitter serotonin, with the accumulation of the primary metabolite 5-hydroxyindole acetic acid (5-HIAA). When these tumors metastasize to the liver, they cause ___ ___, which is characterized by diarrhea, flushing, wheezing, and cardiac valve damage.

Carcinoid tumors
carcinoid syndrome

8

Agents used in the treatment of hyperthyroidism (i.e., Graves disease), such as ____ and methimazole, inhibit the___of tyrosine residues as
well as the coupling reaction.

propylthiouracil
iodination

9

Albinism results from a defect in the conversion of ___ to melanin, with partial or full absence of this pigment in the hair, skin, or eye. The disorder results from a deficiency of the enzyme ___ (which converts tyrosine to melanin) or in defects in tyrosine transport. Lack of melanin increases the risk for developing skin cancer.

tyrosine
tyrosinase

10

In __ disease, dopamine levels are decreased because of a deficiency in conversion of dopa to dopamine. The common characteristics are tremors, difficulty initiating voluntary movement, a masked face with a staring expression, and a shuffling gait. Infantile forms of the disease have been found to be due to defects in __ __

Parkinson
tyrosine hydroxylase.

11

Inhibition of MAO and ___ are both approaches in the treatment of neuropsychiatric disorders such as depression and Parkinson disease.

catecholamine O-methyltransferase (COMT)

12

Patients with pheochromocytomas overproduce adrenally synthesized catecholamines and have increased levels of ___; urinary levels of VMA are used to diagnose these tumors.

vanillylmandelic acid (VMA)

13

__ is a structural analog of folic acid that inhibits dihydrofolate reductase. It functions primarily by inhibiting purine synthesis and, therefore, slows down cell proliferation as in __ or autoimmune diseases like rheumatoid arthritis.

Methotrexate
cancer

14

___ is a folate analog that binds specifically to bacterial dihydrofolate reductase. It is a potent antibacterial compound often used in conjunction with
sulfonamides, which also inhibit the same pathway in bacteria.

Trimethoprim

15

Spina bifida and anencephaly, the most common neural tube defects, are reduced by supplementation with folic acid before conception and during the___trimester of pregnancy.

first

16

1. A 56-year-old man with long-standing, poorly controlled diabetes visits his primary care physician for a follow-up after a recent hospitalization. The patient experienced an episode of acute renal failure while in the hospital, and his creatinine level rose to 3.4 (normal, 0.7 to 1.5). Creatinine, a marker of kidney function, is
produced from which of the following precursors?
(A) Glutamine, aspartic acid, and CO2
(B) Glutamine, cysteine, and glycine
(C) Serine and palmityl CoA
(D) Glycine and succinyl CoA
(E) Glycine, arginine, and SAM

E. Creatinine is formed from the cyclization of creatine phosphate, which is formed from glycine, arginine, and SAM. Glutamine, aspartic acid, and CO2 are involved in the
synthesis of purines and pyrimidines. Glutamine, cysteine, and glycine form the antioxidant molecule glutathione. Serine and palmityl CoA form sphingosine. Glycine and succinyl CoA are the precursors to the formation of heme.

17

2. A 75-year-old man experiences severe chest pain radiating down his left arm. He calls 911 and is transferred to the emergency room where an electrocardiogram indicates that he had a myocardial infarction. Serum levels of cardiac creatine kinase are found to be elevated. What is the biologic role of the product of this
enzyme?
(A) An intracellular antioxidant
(B) A storage form of high-energy phosphate
(C) An inhibitory neurotransmitter
(D) Stimulates the release of hydrochloric acid from the stomach
(E) A bactericidal product produced by macrophages

B. Cardiac creatine kinase phosphorylates creatine to form creatine phosphate, a source of high-energy phosphate in muscle cells. Glutathione functions as an intracellular antioxidant. GABA is an example of an inhibitory neurotransmitter. Histamine, which is derived from histidine, stimulates the release of hydrochloric acid from the stomach. Nitric oxide is one of the bactericidal substances (free radicals) produced by macrophages.

18

3. A couple of African American descent gives birth to a boy after an otherwise uneventful pregnancy. The child is exceptionally fairskinned and has almost white hair. Further examination reveals red pupils. A postnatal
screen is likely to confirm the deficiency of which of the following enzymes in the child?
(A) Peroxidase
(B) Inducible nitric oxide synthase (iNOS)
(C) Glutathione reductase
(D) Tyrosinase
(E) Phenylalanine hydroxylase

D. Albinism results from a defect in the melanocyte isozyme of tyrosinase, which is required for the conversion of tyrosine to dihydroxyphenylalanine, on the pathway to melanin. Peroxidase is important in the formation of thyroid hormone. Glutathione reductase is an NADPH-requiring enzyme involved in regenerating oxidized glutathione. Phenylalanine hydroxylase converts phenylalanine to tyrosine; the absence of this enzyme leads to phenylketonuria.

19

4. A 40-year-old woman complains of decreased energy, significant weight gain, and cold intolerance. She is seen by her family physician, who has laboratory tests done that indicate she has a decreased level of thyroid
hormone. Which of the following amino acids is iodinated in mature thyroid hormone?
(A) Serine
(B) Threonine
(C) Tryptophan
(D) Tyrosine
(E) Phenylalanine

D. Thyroid hormone is an iodinated molecule produced by several complex reactions in the follicular cells of the thyroid and the colloid. Certain tyrosine residues are iodinated in the precursor protein thyroglobulin. The side chains of serine, threonine, tryptophan, or phenylalanine
are not substrates for iodination in thyroglobulin.