Biochem - Nutrition (Part 3: Vitamins E, K, Zinc, Ethanol metabolism, & Malnutrition) Flashcards

Pg. 96-97 in First Aid 2014 Sections include: -Vitamin E (tocopherol/tocotrienol) -Vitamin K -Zinc -Ethanol metabolism -Malnutrition

1
Q

What are 2 other names for Vitamin E?

A

Vitamin E (tocopherol/tocotrienol)

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2
Q

What is the function of Vitamin E (tocopherol/tocotrienol)?

A

Antioxidant (protects erythrocytes and membranes from free radical damage); Think: “E is for Erythrocytes”

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3
Q

With what drug in particular can Vitamin E interact, and how so?

A

Can enhance anticoagulant effects of warfarin

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4
Q

What are 4 signs/symptoms associated with Vitamin E (tocopherol/tocotrienol) deficiency?

A

(1) Hemolytic anemia (2) Acanthocytosis (3) Muscle weakness (4) Posterior column and Spinocerebellar tract demyelination

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5
Q

Compare/Contrast Vitamin E (tocopherol/tocotrienol) deficiency to Vitamin B12 deficiency.

A

Neurological presentation may appear similar to vitamin B12 deficiency, but without megaloblastic anemia, hypersegmented neutrophils, or increase serum methylmalonic acid levels

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6
Q

What is the function of Vitamin K?

A

Cofactor for the gamma-carboxylation of glutamic acid residues on various proteins required for blood clotting; Think: “K is for Koagulation”

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7
Q

What synthesizes Vitamin K?

A

Synthesized by intestinal flora

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8
Q

What are the clotting factors and/or anticoagulatory proteins for which Vitamin K is necessary?

A

Necessary for the activation of clotting factors II, VII, IX, X, and proteins C and S.

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9
Q

What drug functions as a Vitamin K antagonist?

A

Warfarin - Vitamin K antagonist

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10
Q

In what patient population does Vitamin K deficiency typically present, and why? What are 3 lab findings of significance in this presentation?

A

Neonatal hemorrhage with increased PT and increased aPTT but normal bleeding time (neonates have sterile intestines and are unable to synthesize vitamin K).

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11
Q

Besides in neonates, in what other context can Vitamin K deficiency occur?

A

Can also occur after prolonged use of board-spectrum antibiotics

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12
Q

What are the considerations/approaches for Vitamin K deficiency prevention in neonates?

A

(Vitamin K) Not in breast milk; Neonates are given vitamin K injection at birth to prevent bleeding diathesis

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13
Q

What are important functions of Zinc?

A

Essential for activity of 100+ enzymes. Important in the formation of zinc fingers (transcription factor motif).

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14
Q

What are 6 signs/symptoms associated with Zinc deficiency?

A

(1) Delayed wound healing (2) Hypogonadism (3) Decreased adult hair (axillary, facial, pubic) (4) Dysgeusia (5) Anosmia (6) Acrodermatitis enteropathica

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15
Q

To what condition may Zinc deficiency predispose patients?

A

May predispose to alcoholic cirrhosis

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16
Q

Draw out the major reactions of ethanol metabolism, including its locations.

A

See p. 97 in First Aid 2014 for reactions at the top of the page

17
Q

What is the limiting reagent in ethanol metabolism?

A

NAD+ is the limiting reagent.

18
Q

By what kinetics does alcohol dehydrogenase operate?

A

Alcohol dehydrogenase operates via zero-order kinetics

19
Q

What molecular change does ethanol metabolism cause in the liver? What are 3 effects of this change related to chronic alcoholism? What is the end result of these effects? What additional effects does this molecular change have?

A

Ethanol metabolism increase NADH/NAD+ ratio in liver, causing: (1) Pyruvate => lactate (lactic acidosis) (2) Oxaloacetate => malate (prevents gluconeogenesis => fasting hypoglycemia) (3) Glyceraldehyde-3-phosphate => Glycerol-3-phosphate (combines with fatty acids to make triglycerides => hepatosteatosis); End result is clinical picture seen in chronic alcoholism; Additionally, increased NADH/NAD+ ratio disfavors TCA production of NADH => increased utilization of acetyl-CoA for ketogenesis (=> ketoacidosis) and lipogenesis (=> hepatosteatosis)

20
Q

What is the mechanism of Fomepizole? For what is it an antidote?

A

Fomepizole - inhibits alcohol dehydrogenase and is an antidote for methanol or ethylene glycol poisoning

21
Q

What is the mechanism of Disulfiram? What biochemical effect does it have, and how does this present?

A

Disulfiram - inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to hangover symptoms)

22
Q

Draw the reaction of pyruvate breaking down in anaerobic glycolysis, including factors involved and its product.

A

See p. 97 in First Aid 2014 for visual at right

23
Q

Draw the reaction of Oxaloacetate breaking down in the TCA cycle, including factors involved and its product.

A

See p. 97 in First Aid 2014 for visual at right

24
Q

What reaction does alcohol dehydrogenase catalyze, and where? What effect does it have on NAD+/NADH?

A

Ethanol conversion to Acetaldehye in cytosol; Makes NAD+ into NADH

25
Q

What reaction does acetaldehyde dehydrogenase catalyze, and where? What effect does it have on NAD+/NADH?

A

Acetaldehyde conversion to Acetate in mitochondria; Makes NAD+ into NADH

26
Q

What are 2 types of malnutrition?

A

(1) Kwashiorkor (2) Marasmus

27
Q

What is Kwashiorkor, and what are 3 signs/symptoms that characterize it? What is its typical clinical picture?

A

Protein malnutrition resulting in (1) skin lesions, (2) edema, (3) liver malfunction (fatty change due to decrease apolipoprotein synthesis). Clinical picture is small child with swollen belly. ; Think: “Kwashiorkor results from a protein-deficient MEAL - Malnutrition, Edema, Anemia, Liver (fatty).”

28
Q

What is Marasmus, and what are 4 signs/symptoms that characterize it?

A

Total calorie malnutrition resulting in (1) tissue and (2) muscle wasting, (3) loss of subcutaneous fat, and (4) variable edema; Think: “Marasmus results in Muscle wasting”