Vitamins

Front 1

In the diet, vitamin A is present in 2 forms: 1) preformed vitamin A or _____, which is found in animal tissues; and 2) a groups of precursor compounds, the _____, which is synthesized by plants.

Back 1

retinol; carotenoids

Front 2

In addition to retinol, at least 2 other forms of vitamin A exist in the body: _____ and _____, both of which are synthesized from retinol.

Back 2

retinal and retinoic acid

Front 3

Certain functions such as the ability to see in dim light require only ______.

Back 3

retinal

Front 4

Distribution to extrahepatic tissues involving complexing of retinol with a specific carrier protein in the liver known as retinol-binding protein and then with a second hepatic protein, ____, upon its release from circulation.

Back 4

transthyretin (prealbumin)

Front 5

Toxicity of vitamin A occurs when liver storag and retinol-binding protein capacities are exceeded. In this situation, the vitamin is transported nonspecifically to cells where it exerts a membrano (-lytic or -genic) action.

Back 5

membranolytic

Front 6

The vitamin A in parenteral multiple-vitamin formulations, as well as in single-entity products, is usually synthetic ____ or ____ ____.

Back 6

retinol or retinyl palmitate

Front 7

At least three different physiological functions are attributed to vitamin A: ____, ____ and ____ and _____.

Back 7

vision, growth and differentiation and reproduction

Front 8

Rhodopsin is the chromophore found in the ___ (rod or cone ) cells of the retina.

Back 8

rod

Front 9

____or night blindness is the inability to see in dim light and is one of the first symptoms of vitamin A deficiency.

Back 9

Nyctalopia

Front 10

Corticosteroids ____ (increase ordecrease) the rate of vitamin A transport from the liver, resulting in elevated serum levels and depletion of reserves.

Back 10

increase

Front 11

Corticosteroids are associated with the release of retinol binding protein release from the liver and subsequent ____ (increased, decreased) plasma vitamin A levels.

Back 11

increased

Front 12

More effective utilization of vitamin A is found when adequate vitamin __ is provided, especially when vitamin A nutriture is marginal.

Back 12

vitamin E

Front 13

In the adult, the average liver vitamin A concentration is ___IU/g while the storage capacity is about 7000 IU/g.

Back 13

800

Front 14

Over ___% of the body's total vitamin A content is deposited in the liver.

Back 14

90

Front 15

In the eye, ___ is converted to the aldehyde retinal, the chromophore of the visual pigment rhodopsin.

Back 15

retinol

Front 16

Single entity parenteral vitamin A products are approved for ____(intravenous, intramuscular) injection only.

Back 16

intramuscular

Front 17

Since the degradation of circulating vitamin A-retinol-binding protein complex occurs in the ___, impaired ____function typically results in elevation of serum vitamin A.

Back 17

kidney; renal

Front 18

Vitamin A activity can be found expressed as ____, ____, _____ or ____.

Back 18

microg, USP units, IU or microg retinol equivalents

Front 19

Tissues most affected by vitamin A deprivation are those with _____ proliferation rates.

Back 19

high

Front 20

Methods for determining retinol concentration are _____, _____, and _____.

Back 20

high performane liquid chromatorgraphy, spectrophotometry and fluorometry

Front 21

When given by intramuscular injection to vitamin A deficient children, utilization of pharmacologic amounts of retinyl palmitate is better in the form of ____ ____ ____.

Back 21

water-miscible preparation

Front 22

The measure of plasma ____ ___ ___ in patients without malnutrition is thought ot be a sensitive indicator of vitamin A status

Back 22

retinol-binding protein

Front 23

Cholecalciferol (D3) can be synthesized in the skin upon exposure to ____ irradiation.

Back 23

ultraviolet

Front 24

Ergocalciferol (D2) is produced form _____ sterols and is the vitamer present in most vitamin formulations.

Back 24

plant

Front 25

Vitamin D is uniques in that it must first be activated by sequential hydroxylation reactions in the ____ and ____.

Back 25

liver and kidney

Front 26

Mobilization of calcium from bone and resorption of calcium from kidney require the presence of both _____ and _____.

Back 26

1,25 (OH)2D and parathyroid hormone

Front 27

____ or _____ disease may therefore, retard the synthesis of hydroxylated D and thuse reduce the effectiveness of the vitamin administered.

Back 27

Hepatic or renal

Front 28

Vitamin D should not be administered to patients with ____ or woth evidence of vitamin D toxicity.

Back 28

hypercalcemia

Front 29

The liver may reatine and store as much as ___ to ____ % of vitamin D

Back 29

60-80%

Front 30

Transport of vitamin D from the liver and vitamin D synthesized in the skin occurs by a vitamin D-binding protein and, to a small extent, ______.

Back 30

albumin

Front 31

Transport of vitamin D3 from the skin to the liver occurs by way of a specific vitamin D-binding protein , ____-____; agains, little or none is carried by albumin.

Back 31

alpha-globulin

Front 32

The synthesus of 1,25 (OH)2 D is controlled in part by the levels of serum _____ and ______.

Back 32

calcium and phosphorous

Front 33

Under normal conditions, more than 95% of vitamin D excreted from the body occurs by way of the _____.

Back 33

feces

Front 34

Patients on long term TPN should be monitored for the appearance of histologic and biochemical indices of ____ _____.

Back 34

bone disease

Front 35

Symptoms of vitamin D overdosage are hyperphosphatemia, _____ and _____.

Back 35

hypercalcemia, and hypercalciuria

Front 36

Metabolism of vitamin D to its active metabolites may be immpaired in the presence of _____ and _____.

Back 36

phenytoin and barbituates

Front 37

The name assigned to vitamin E was ____, from the Greek tokos meaning childbirth, and pherine meaning to bear.

Back 37

tocopherol

Front 38

Vitamin E in the diet is derived primarily from ____.

Back 38

plants

Front 39

The primary action of vitamin E is a retardant of cellular ____ oxidation and peroxidation.

Back 39

lipid

Front 40

_____, a tripeptide containing methionine, is thought to act in regenerating tocopherol molecules.

Back 40

Glutathione

Front 41

Hemolytic anemia in the neonate is aggravated by administration of ____ unless vitamin E is also administered.

Back 41

iron

Front 42

Dietary vitamin E is composed of at least ___ structurally related compounds.

Back 42

eight (8)

Front 43

By definition, 1 mg of d-alpha-tocopherol is equivalent to ___ tocopherol equivalent, which is also 1.49 IU.

Back 43

one (1)

Front 44

Humans absorb ___ to ___% of vitamin E ingested.

Back 44

25-85%

Front 45

Elimination of vitamin E from the body occurs chiefly by conversion to a water soluble lactone, esterification with glucuronic acid and excretion of the gluceronide by way of the ____.

Back 45

urine

Front 46

In general, a plasma level of ______ d-alpha tocopherol is indicative of adequate vitamin E status in children, adolescents and adults.

Back 46

0.5 mg/dL

Front 47

Absorption of vitamins A, D, and E to ____ and ____ has been documented.

Back 47

plastic bags and plastic infusion sets.

Front 48

A report of a toxic interaction between parenteral _____ and vitamin E is cause for concern.

Back 48

lipid emulsion

Front 49

Conditions that are associated with a malabsorption of _____ may induce a secondary vitamin E deficiency.

Back 49

fat

Front 50

The most important naturally occuring forms are K1, found in ____ _____ and Ks, synthesized by _____ and ______.

Back 50

green plants; animals and bacteria

Front 51

The vitamin functions as a coenzyme for the post-translational carboxylation of at least ____ clotting factors in which uncarboxylated protein precursors are converted to functional proteins containing alpha-carboxyglutamic acid residues.

Back 51

four

Front 52

A deficiency of vitamin K or abnormalities in the hepatic synthesis of clotting proteins results in prolonged _____ time.

Back 52

prothrombin

Front 53

The synthesis of four-coagulation factors--____(Factor II), ______ (factor VII), _____(factor IX) and _____(factor X) is carried out by a post-translational vitamin K dependent enzyme system.

Back 53

Prothrombin, pronconvertin, thromboplastin, Stuart factor.

Front 54

Several other vitamin K carboxyglutanyl-containing proteins that have been isolated from bone, kidney, and liver may also play a role in other areas of metabolism. They are thought to be related to ____ _____ formation and possible to synthesis of _____.

Back 54

bone crystal; phospholipids

Front 55

The degree of bioavailabilidy of ingested vitamin K from food sources is estimated at from ____ to ____ % and is, in part, dependent upon the degree of enterohepatic circulation.

Back 55

10-70%

Front 56

The rate of hepatic uptake is much faster folllowing parenteral administration of K1, as about ___% of the dose appears in teh liver within one hour.

Back 56

50

Front 57

In order to confirm the diagnosis of vitamin K deficiency, ____ time should normalize following vitamin K supplementation; if no imporvement is observed, abnormal liver function should be suspected.

Back 57

prothrombin

Front 58

Vitamin K will not counteract the anticoagulat action of _____.

Back 58

heparin

Front 59

When INRs are less than _____, when there is no bleeding and when there is no indication for rapid reversal of warfarin therapy, doses may be omitted until the INR is therapeutic with dose initiation of warfarin at a loer dose.

Back 59

6

Front 60

Hypoprothrombinemia may also result from an inability to utilize vitamin K due to _____ damage and inthis instance, supplemental vitamin K is not efficacious.

Back 60

hepatic

Front 61

Large doses of ____, a commonly used analgesic-antipyretic, willl produce an anticoagulation state that is reversed by supplemental vitamin K administration.

Back 61

salicylate

Front 62

In parenterally fed patients who do not require anticoagulant therapy, injection of vitamin K is recommended in doses of ___ to ____ mg/week.

Back 62

2-4 mg/week

Front 63

In the newborn infant, the concentrations of prothrombin and other clotting agents
fall precariously and the infant may bleed spontaneously. This is known as ______
disease of the newborn.

Back 63

hemorrhagic

Front 64

Fat emulsions may contribute ___________ amounts of vitamin K (10% - 30 microg/100mL;
20% - 60 microg/100mL).

Back 64

significant

Front 65

Toxicity from Vitamin K has been relegated primarily to cases involving the administration
of excessive amounts of __________ vitamin K analogs.

Back 65

water soluble

Front 66

_______ damage may prevent adequate synthesis of active clotting factors, despite
the presence of adequate vitamin K.xa

Back 66

Hepatic

Front 67

The active coenzyme form of thiamin is ______ ______ .

Back 67

thiamin pyrophosphate

Front 68

"Cardiac" or "___" (wet, dry) beriberi consists of an abnormal electrocardiogram with
prolonged reversal of T-waves, prolongation of the QRS interval, palpitations, gallop
rhythm, cardiomegaly with elevated venous pressure and diminished vital capacity
with dyspnea and myocardial lesions.ment

Back 68

dry

Front 69

So-called "___" (wet, dry) beriberi refers to the generalized edema that probably
results from inadequate protein intake as well as poor cardiac functioning due to thiamin
deficiency.uid=607

Back 69

wet

Front 70

Thiamin is destroyed relatively rapidly above pH _ by autoclaving and at pH 7 at
room temperature.ument

Back 70

5

Front 71

Thiamin as thiamin pyrophosphate participates as a coenzyme in __________
____________ reactions.

Back 71

oxidative decarboxylation

Front 72

An additional important TPP-requiring enzyme is _________. (This enzyme is essential
in the pentose phosphate pathway, which is the chief source of pentose sugars for the
cell and a major source of NADPH for fatty acid and other metabolic biosynthesis).r

Back 72

transketolase

Front 73

Thiamin itself is a pharmacologic _________ (antagonist, promotor) of acetylcholine
transmission.

Back 73

antagonist

Front 74

At low concentrations, thiamin is absorbed by an ______ (active, passive) process and
at high concentrations by ______ (active, passive) diffusion..

Back 74

active; passive

Front 75

In humans, the total amount of thiamin in the body is approximately __ mg.

Back 75

30

Front 76

The muscles contain approximately __ % of total body thiamin.

Back 76

50

Front 77

Approximately __ % of the thiamin in the body is present as TPP.

Back 77

80

Front 78

White blood cells contain about __ times more thiamin than erythrocytes.

Back 78

10

Front 79

The daily excretion of thiamin is in the range of 100 ìg/day with daily recommended
(Food and Nutrition Board) intakes of __ mg/1,000 kcal.

Back 79

0.5

Front 80

The most reliable method of assessing thiamin status is the measurement of whole
blood or erythrocyte ___________ activity.

Back 80

transketolase

Front 81

Patients consuming excessive _________ (substrate providing seven kcal energy per
gram) at the time TPN is started are at increased risk of developing thiamin deficiency.

Back 81

alcohol

Front 82

Deficiency of the electrolyte_____________ may lead to a decrease in tissue thiamin
levels and disturbances in thiamin function.

Back 82

magnesium

Front 83

Deficiencies of vitamins _____ and _____ may result in decreased levels of thiamin in
tissues and _____ (vitamin) deficiency may result in malabsorption of thiamin.Š

Back 83

B1 and B12; folate

Front 84

Because there is some evidence that older persons use thiamin less efficiently, it is
recommended that they maintain an intake of __________ mg/day, even if they consume
less than 2000 kcal daily.ms

Back 84

1

Front 85

The multivitamin formula should always be added after dilution of the amino acid
solution in order to minimize the contact of thiamin with the _________ preservatives in
certain undiluted amino acid solutions.

Back 85

bisulfite or metasulfite

Front 86

The commercially available parenteral thiamin compound is ________, which is
included in all parenteral multiple-vitamin formulations.

Back 86

thiamin hydrochloride

Front 87

The potency of thiamin can be assessed by a _______ procedure or a chemical ______
method.

Back 87

microbiological; flourescence

Front 88

Several __________ factors found in foods include a thermally labile factor in viscera
of fresh water fish, shellfish and tea leaves..

Back 88

antithiamin

Front 89

Riboflavin or vitamin B2, is a water-soluble compound that is converted by the body
to two important prosthetic groups: ________ _________________ and _______ _______
______________.

Back 89

flavin mononucleotide and flavin adenine dinucleotide.

Front 90

The forementioned enzymes participate in a wide variety of enzyme oxidation systems
requiring the transport of ________ leading to the formation of adenosine triphosphate.

Back 90

electrons

Front 91

Riboflavin and flavin mononucleotides are absorbed in humans by the upper
gastrointestinal tract by a _________-_________mechanism.s..

Back 91

phosphorylation-dephosphorylation

Front 92

The riboflavin transport mechanism is apparently saturable with an upper limit of
approximately __ mg.t

Back 92

25

Front 93

The largest fraction of riboflavin and flavin mononucleotide is thought to be bound
to
________, with smaller quantities of flavins bound to other plasma proteins.Š

Back 93

albumin

Front 94

Riboflavin and flavin mononucleotide are converted to_____ _________ _____________
in the tissues, where binding to specific flavoproteins occurs.

Back 94

flavin adenine dinucleotide

Front 95

The ______ is the major site of storage, containing about one-third of total body
flavins. Kidney and heart are also rich in this vitamin where 70%-90% is in the form of
flavin adenine dinucleotide. Free riboflavin constitutes less than 5% of stored flavins.m

Back 95

liver

Front 96

Flavins are excreted via the ______ of humans almost exclusively in the form of
riboflavin rather than a coenzyme derivative.

Back 96

urine

Front 97

The RDA for riboflavin is ___ mg/1,000 kcal for people of all ages.

Back 97

0.6

Front 98

Exposure of a TPN solution to ordinary lighting conditions can result in a __% fall in
riboflavin concentration within 24 hours. Wrapping the intravenous bottle in aluminum
foil can prevent the photolytic destruction.

Back 98

33

Front 99

Drugs such as chlorpromazine, a phenothiazine derivative and amitriptyline, a tricyclic,
_______ (inhibit, promote) the conversion of riboflavin to the active coenzyme form.39

Back 99

inhibit

Front 100

This ___________ (inhibition, promotion) can be reversed by increasing the riboflavin
intake.

Back 100

inhibition

Front 101

__________ (disease state) causes decreased tissue levels of flavin mononucleotide
and flavin adenine dinucleotide as well as interference with the phosphorylation of
riboflavin.___.

Back 101

hypothyroidism

Front 102

The sodium salt of _________ is the form of riboflavin present in most parenteral
products.e.

Back 102

riboflavin-5-phosphate

Front 103

Copper, zinc, iron, caffeine, theophylline, niacinamide, sodium saccharin, tryptophan,
urea, and ascorbic acid may form___________ or ___________ with riboflavin and flavin
mononucleotides.

Back 103

chelates or complexes

Front 104

The free riboflavin level in human serum appears to be influenced by____________
and is too variable to serve as a useful index of riboflavin status.

Back 104

recent dietary intakes

Front 105

Newborn infants treated by ________ for hyperbilirubinemia may exhibit evidence
of riboflavin deficiency..

Back 105

phototherapy

Front 106

Under normal circumstances, riboflavin excesses are readily metabolized and excreted
and thus pose no hazard, except possibly in the _________.

Back 106

preterm infants

Front 107

A niacin deficiency results in ________, a disease that has been virtually eliminated
from the Western world.

Back 107

pellagra

Front 108

Nicotinic acid is converted in the body to _________, an essential part of the enzyme
system concerned with hydrogen transport (oxidation in the living cell).7

Back 108

nicotinamide

Front 109

Nicotinic acid is an essential component of the coenzymes____ and_____ .

Back 109

NAD and NADP

Front 110

Nicotinic acid, but not ________, is a vasodilator and will also lower blood cholesterol
when taken in pharmacologic amounts.

Back 110

Nicotinamide

Front 111

_________ (common analgesic) has been shown to block niacin-induced flushing from
doses of 925 mg.ument

Back 111

Aspirin

Front 112

Side effects previously reported with __________, such as irregular pulse, tachycardia
and peristalsis have been obviated by the use of _________.&‹

Back 112

nicotinic acid; nicotinamide

Front 113

In humans, _________ is a precursor of niacin, although the efficiency of conversion is
widely variable among individuals.ts.

Back 113

tryptophan

Front 114

The tryptophan to niacin metabolic pathway is inhibited by ___________
(antituberculous medication).ent

Back 114

isoniazid

Front 115

High intake of _______ (amino acid) increases the need for nicotinic acid.

Back 115

leucine

Front 116

Excess leucine increases the activity of picolinate carboxylase which in turn accelerates
the degradation of __________ (amino acid).

Back 116

tryptophann

Front 117

Large doses of nicotinic acid can cause __________ (organ) toxicity.

Back 117

Liver

Front 118

Following digestion, nicotinic acid and tryptophan are absorbed into the portal
circulation and converted to _______ in the liver.

Back 118

NAD

Front 119

Although only small quantities of niacin are present in plasma, higher concentrations
are present in the erythrocytes and leucocytes as ________..

Back 119

NAD

Front 120

The best criterion for evaluating niacin status is thought to be the
_____________:______________ excretion ratio.on/xa

Back 120

2-pyridone:N'-methylnicotinamide

Front 121

Approximately __ mg tryptophan are estimated to be about 1 mg niacin.‹

Back 121

60

Front 122

The tryptophan content of most amino acid solutions is about ___%.

Back 122

0.15

Front 123

The need for niacin in stressed _______ (disease) patients appears higher than the
current recommended dose..

Back 123

oncology

Front 124

_________ (vitamin) is given to schizophrenic patients to stimulate conversion of
tryptophan to NAD.<<

Back 124

pyridoxine

Front 125

___________is the vitamer present in parenteral multiple-vitamin formulations,
whereas _________ ______is found in most single-entity injectable products.=1397

Back 125

Niacinamide; nicotinic acid

Front 126

_________ acts as a reducing agent in many biosynthetic pathways such as fatty acid
synthesis.

Back 126

NADP

Front 127

The primary urinary foms of niacinamide are _______________ and the _____________.

Back 127

N´-methylnicotinamide; 2- and 6-pyridones of N´-methylnicotinamide

Front 128

Elevations of serum __________ and ___________ (hepatic enzymes) are associated
with high doses of niacin.

Back 128

transaminase and bilirubin

Front 129

The American Medical Association/Nutrition Advisory Group guidelines do not
account for the contribution of __________ to the niacin allowance.

Back 129

tryptophan

Front 130

Vitamin C is thought to function in __________ ion transfer and to participate in the
regulation of intracellular oxidation-reduction potential...

Back 130

hydrogen

Front 131

Ascorbic acid is properly classified as a ________ since it is a ______ derivative.

Back 131

carbohydrate; hexose

Front 132

The most well-known function of ascorbic acid is that of a cofactor for prolyl and
lysyl hydroxylases in the synthesis of __________.

Back 132

collagen

Front 133

Iron mobilization from the ______ (organ), but not the _____ is impaired, in ascorbic
acid deficiency.t

Back 133

spleen; liver

Front 134

The synthesis of ____________ apparently requires ascorbic acid for the activity of the
enzyme dopamine-b-hydroxylase.a

Back 134

noradrenaline

Front 135

A principle vitamin C metabolite that should be respected in the setting of renal
failure is _____________...

Back 135

oxalate

Front 136

Ascorbic acid is involved in the synthesis of vasoactive amines by facilitating
hydroxylation of tryptophan to 5-__________________..

Back 136

hydroxytryptophan

Front 137

Ascorbic acid appears to be involved in the metabolism of ____ ____ by preventing
oxidation of _______________.

Back 137

folic acid; tetrahydrofolates

Front 138

Ascorbic acid interacts with iron and _______ and thus influences normal heme function
through the oxidation-reduction of iron and/or by regulating iron absorption and
availability in the intestine.

Back 138

copper.

Front 139

High intakes (>____ mg) are required for maximum saturation of body reserves and
elevation of serum levels > 1 mg/dL.xa

Back 139

100

Front 140

Serum ascorbic acid levels are reduced in chronic __________ diseases and in acute
and chronic infections such as tuberculosis and rheumatic fever.

Back 140

inflammatory

Front 141

Cigarette smoking lowers _______ ascorbic acid levels.

Back 141

plasma.

Front 142

The average body pool of ascorbic acid is approximately ____ mg of which 3% to 4%
is utilized daily.ent

Back 142

1500

Front 143

Pharmacokinetic studies and isotopic ascorbic acid balance studies provide evidence
that intakes of __-__ mg/day will maintain the body pool of 1,500 mg.c=1397

Back 143

40-60

Front 144

At daily intakes up to 100 mg, _______ is the major product excreted. When larger
amounts are ingested, ascorbic acid is mainly excreted intact.er.

Back 144

oxalate

Front 145

The threshold for ascorbic acid is approximately _._ mg/dL of plasma.ion

Back 145

1.4

Front 146

___ milligrams of ascorbic acid can alleviate and cure scurvy; however, very little
tissue reserves are attained with this level.__..

Back 146

Ten

Front 147

A large oral dose of _ - __ g of ascorbic acid may cause nausea or vomiting. Diarrhea
is a likely side effect of doses in this range due to its osmotic activity.ns.Š

Back 147

5 - 10.

Front 148

Amino acid solutions with a lower pH, without bisulfite and containing ________
(amino acid) have been associated with the least vitamin C degradation.

Back 148

cysteine

Front 149

__________ (antiinfectives) increase urinary excretion of vitamin C two- to three-fold.

Back 149

sulfonamides

Front 150

________ (common analgesic) increases the urinary excretion of ascorbic acid and leads to
a reduction in platelet ascorbic acid levels.

Back 150

acetylsalicylic acid

Front 151

The primary mechanism for ascorbate absorption in humans is _______ ________.

Back 151

carrier mediated

Front 152

Acceptable ascorbic acid serum levels are _________mg/dL.

Back 152

>0.20

Front 153

_________ is a likely side effect of oral doses of 5-10g ascorbate/day.

Back 153

diarrhea

Front 154

Ascorbic acid excreted in the stool will cause a flase-negative reaction for ____ ____ ____.

Back 154

occult blood loss

Front 155

Pantothenic acid functions primarily as a component of ________ _ and within the
4'-phosphopantotheine moiety of the acyl carrier protein of fatty acid synthetase..Š

Back 155

coenzyme A

Front 156

Pantothenic acid is the prosthetic group on ____ ______ ______.

Back 156

acyl carrier protein

Front 157

More than 70 enzymes are known to require _________ A or acyl carrier protein.D

Back 157

coenzyme

Front 158

According to urinary pantothenate data, the percent bioavailability of pantothenic
acid has been estimated to be about __% .

Back 158

50

Front 159

The highest percentage of pantothenic acid appears to be bound in tissue as _________
_ followed next by 4'-phosphopantotheine, with small amounts of free pantothenic acid
remaining.

Back 159

coenzyme A

Front 160

Based on data from animal studies, the _____ (organ) has the highest concentration of
pantothenic acid followed by the adrenal gland.s.

Back 160

liver

Front 161

Serum principally contains ______ (free, bound) pantothenic acid.

Back 161

free

Front 162

Pantothenic acid administered orally or by injection is rapidly excreted via _____.

Back 162

urine

Front 163

Chronic ulcerative or granulomatous colitis has been associated with reduced ______
_ activity and is postulated to result from a block in the conversion of free to bound
pantothenic acid.

Back 163

coenzyme A

Front 164

Pantothenic acid deficiency in humans has been found to lead to lowered blood
______ (substrate) levels and an increased sensitivity to ________ (hormone).

Back 164

sugar; insulin

Front 165

Patients with diabetes mellitus are reported to have _______ (elevated, reduced)
urinary pantothenic acid excretion.

Back 165

elevated

Front 166

_____ synthesis is dependent on succinyl CoA along with glycine and Vitamin B6.

Back 166

Heme

Front 167

Acyl carrier protein acts as the carrier in the synthesis of ______ ______.

Back 167

fatty acids

Front 168

The form of pantothenic acid in most parenteral multiple-vitamin preparations is
d-__________ _________.

Back 168

pantothenyl alcohol

Front 169

The major form of pantothenic acid in the urine is ____ ______ _____.

Back 169

intact pantothenic acid

Front 170

Pharmacological doses (250 mg) of pantothenic acid may result in ______, ________
(allergic reactions).

Back 170

itching, dermatitis

Front 171

The essential role of vitamin B6 in the maintenance of the functional integrity of the
brain is illustrated by the fact that all compounds implicated as _____________ are
synthesized and/or metabolized by the aid of the vitamin B6-dependent enzymatic
reactions. These include dopamine, norepinephrine, serotonin, tyramine, tryptamine,
taurine, histamine and g-aminobutyric acid.

Back 171

neurotransmitters

Front 172

_________ (amino acid) metabolism requires a number of pyridoxal-5-phosphatecatalyzed
reactions.

Back 172

Tryptophan

Front 173

When a deficiency occurs, tryptophan metabolism is altered that may result in _______
(increased, reduced) urinary xanthurenic acid, kynurenine, 3-hydroxykynurenine and
quinolinic acid; the excretion of nicotinic acid and N'-methylnicotinamide may be _______
(reduced, increased).

Back 173

Increased; reduced

Front 174

The total body pool consists of ___ to ___ mg of pyridoxine.

Back 174

16 to 25 mg

Front 175

_______ pyridoxal-5-phosphate measurement is considered by many investigators to
be a sensitive and reliable indicator of vitamin B6 nutritional status.

Back 175

plasma

Front 176

The ____ (organ) has been demonstrated to be the principal, if not the sole, organ
responsible for the formation of plasma pyridoxal-5-phosphate from either pyridoxine
or pyridoxal.

Back 176

liver

Front 177

The _____ (organ) possesses an apparently unique transport mechanism that provides
for the efflux of pyridoxal-5-phosphate into the circulation. This transport mechanism is
absent in erythrocytes and other tissues.

Back 177

liver

Front 178

pyridoxal-5-phosphate is bound principally to ________ in erythrocytes and to glycogen
phosphorylase in skeletal muscle.

Back 178

hemoglobin

Front 179

The principle storage pool for vitamin B6 in the body is _______ ____________ in
________.

Back 179

glycogen phosphorylase in the muscle

Front 180

Megadoses of pyridoxine can cause ________ _______ system toxicity.

Back 180

central nervous

Front 181

Vitamin B6 is required for the conversion of tryptophan to _______.

Back 181

niacin

Front 182

Vitamin B6 is a collective term for a group of compounds including __________,
__________ and __________.

Back 182

pyridoxine, pyridoxal, pyridoxamine

Front 183

The major coenzyme form of viatmin B6 is _______ _______.

Back 183

pyridoxal phosphate

Front 184

___________ is the major excretory product of vitamin B6
metabolism and is an indicator of ____________ status.

Back 184

Pyridoxic acid, recent or short-term

Front 185

The recommended dietary allowance for adult men and adult, nonpregnant women
is ______ and _______, respectively.

Back 185

2 mg, 1.6 mg

Front 186

Intravenous recommendations are approximately ______ the RDA for adults.

Back 186

twice

Front 187

Vitamin B12 is a water-soluble vitamin that functions as a coenzyme required for ____
synthesis as well as ______ _____ and ____ metabolism.

Back 187

DNA; amino acid; lipid

Front 188

In cyanocobalamin, the anionic (trace element)group in coordinate linkage with the
cobalt is _______.

Back 188

cyanide

Front 189

Vitamin B12 is required for the synthesis of _______ and therefore, DNA synthesis
and cell division are B12-dependent.

Back 189

thymidylate

Front 190

Patients, dentists or anesthesiologists treated with or exposed to prolonged ______
_____ anesthesia (6 days or more) can develop pancytopenia and the marrow will show
reduced cellularity with megaloblastic erythropoiesis.

Back 190

nitrous oxide

Front 191

Prolonged _______ (medication category) therapy may suppress gastric acidity and
production of pepsin thus impairing release of vitamin B12 from animal protein foods
and consequently lowering vitamin B12 levels.

Back 191

H2 antagonists

Front 192

The mechanism of vitamin B12 absorption takes place almost entirely in the ____.

Back 192

ileum

Front 193

The cobalamin entering the blood after oral ingestion appears to be bound to
________ II, which facilitates the uptake of cobalamin by a large number of tissues.

Back 193

transcobalamin

Front 194

The two coenzyme forms of cobalamins are______________ and __________.

Back 194

adenosylcobalamin and methylcobalamin

Front 195

The plasma clearance of B12 may be used to measure the ______________ filtration
rate.

Back 195

glomerular

Front 196

Once the plasma binders are saturated with vitamin B12, the free vitamin B12 in
plasma is excreted by the kidney in the same way as ________ (e.g., it is filtered by the
glomerulus and is neither excreted nor absorbed by the renal tubules).

Back 196

insulin

Front 197

B12 bioavailability (by mouth) is approximately __ % to __ %, depending on dose.

Back 197

16-28%

Front 198

Prolonged exposure to sunlight causes a loss of 10% of cyanocobalamin per ___
minute exposure.

Back 198

30

Front 199

A dietary intake of ___ μg daily can be expected to sustain average normal adults.

Back 199

one

Front 200

Vitamin B12 deficiency results in _________, _________anemia, in neurological
symptoms due to demyelination of the spinal cord and brain and the optic and
peripheral nerves and in other less specific symptoms (e.g., sore tongue, weakness).

Back 200

macrocytic, megaloblastic

Front 201

Adult _______ _______ is the most commonly acquired cause of failure to assimilate
cobalamins.

Back 201

pernicious anemia

Front 202

Being water-soluble, excess vitamin B12 is excreted in the _____, but it is not readily
removed with ________ because it highly protein-bound.

Back 202

urine; dialysis

Front 203

The most useful confirmatory diagnostic test is serum ___________ ______ as it
allows for the distinction between a folate and vitamin B12 deficiency.

Back 203

methyl malonic acid (MMA)

Front 204

The conversion of homocysteine to methionine requires _______ ___________ as the
coenzyme.

Back 204

methyl cobalamin

Front 205

Adenosylcobalamin is required by methyl malonyl CoA mutase, the enzyme that
converts _________ ___ (substrate) to __________ ____ (product).=(n

Back 205

L-methylmalonyl CoA, succinyl CoA

Front 206

The loss of vitamin B12 from the body is primarily due to loss of _______ which
contains cobalamin in the feces.

Back 206

bile

Front 207

A vitamin B12 deficiency could lead to the accumulation of both ________ (substrate)
and __________ (substrate).

Back 207

homocysteine, methylmalonyl CoA

Front 208

A deficiency of this vitamin may be associated with excessive consumption of raw
egg whites containing the biotin antagonist, ______.

Back 208

avidin

Front 209

Foodstuffs of _____ (plant, animal) origin have a greater free biotin content than
food of ______ (plant, animal) origin.

Back 209

plant; animal

Front 210

Biotin deficiency may interfere with cholesterol metabolism, as evidenced by
hypercholesterolemia in several species, including humans. Biotin is generally
incorporated in parenteral solutions in the form of __ (d,l)-biotin.

Back 210

d

Front 211

The _______ part of the human small intestine is the site of maximum biotin transport.

Back 211

proximal

Front 212

__________ is the only protein in human serum that exchanges with biotin and, thus,
could be the major carrier of biotin in plasma and, as such, functions in biotin transport.

Back 212

Biotinidase

Front 213

hanges in ______ _______, ________, _______ or _________ biotin levels may provide
evidence as to the existence of a biotin deficiency.

Back 213

whole blood, serum, plasma, urinary

Front 214

Biotin deficiency can be produced by the ingestion of large amounts of ______.
Anorexia, nausea, vomiting, glossitis, pallor, mental depression, alopecia, a dry scaly
dermatitis and an increase in serum cholesterol and bile pigments may characterize the
deficiency. Hair loss has been observed in adults on long-term TPN without added
biotin.

Back 214

avidin

Front 215

_______ consumption may be associated with low biotin levels.

Back 215

Alcohol

Front 216

Multiple carboxylase deficiencies due to inborn errors of metabolism of ________
________ and ____________ have been documented.

Back 216

holoenzyme synthetase, biotinidase

Front 217

Biotin dependent enzymes transfer ______ ________ from bicarbonate to an organic
substrate.

Back 217

carbon dioxide

Front 218

The four biotin-dependent enzymes of importance in mammalian metabolism are
_________________, ___________________, ____________________ and
_________________.

Back 218

pyruvate carboxylase, propionyl-coenzyme A carboxylase, 3-methylcrotonyl-coenyme
A carboxylase, acetyl-coenzyme A carboxylase

Front 219

Pyruvate carboxylase participates in a regulated pathway in __________________.

Back 219

gluconeogenesis

Front 220

Acetyl CoA carboxylase converts _________ to ____________ and catalyzes the
commitment and rate limiting step of fatty acid synthesis.

Back 220

acetyl CoA, malonyl CoA

Front 221

Folate is a generic term for this water-soluble B-complex vitamin which exists in
many different forms and is essential for ___-____ transfer reactions.

Back 221

one-carbon

Front 222

____________ is the formyl derivative and an active form of folic acid. It is used
clinically in circumventing the action of folate reductase inhibitors.

Back 222

Leukovorin (folinic acid, citrovorum factor)

Front 223

Approximately __% of dietary folate is estimated by the National Academy of
Sciences/National Research Council to be bioavailable.

Back 223

50%

Front 224

Up to ___% of protein-bound serum folates are associated with albumin.

Back 224

50%

Front 225

A reduction in serum folate level is an early sign in the progression of a folate
deficiency and levels less than _ ng/mL are considered low.

Back 225

3

Front 226

Reduction in red cell folate concentration precedes the development of _________
anemia, which is a late finding in the progression of folate deficiency.

Back 226

megaloblastic

Front 227

Low ______ folate levels usually precede low red cell folate levels.

Back 227

serum

Front 228

Folate supplementation in the patient with ________ anemia will result in a remission
of the hematological abnormalities, but not the neurological lesions, and as such can
mask diagnosis.

Back 228

pernicious

Front 229

Folic acid itself is not biochemically active but becomes so after it has undergone
________________.

Back 229

reduction

Front 230

Folic acid analogues (antagonists) such as methotrexate and amethopterin inhibit the
enzyme ___________ ___________.

Back 230

dihydrofolate reductase

Front 231

Methionine synthetase requires both vitamin B12 and folate and lack of either will
prevent the regeneration of ______________ and ultimately _____________ which is
required for DNA synthesis.

Back 231

tetrahydrofolate, 5,10-methylene tetrahydrofolate

Front 232

The recommended dietary allowance for adult men and nonpregnant, adult women
is _____ and ______ per day, respectively.

Back 232

200 μg, 180 μg

Front 233

Dietary folate is predominantly polyglutamyl folate which must be converted to the
____________ form by an intestinal conjugase enzyme.

Back 233

monoglutamate

Front 234

Only the _____ (levo, dextro) - rotatory form of carnitine is biologically active.

Back 234

levo

Front 235

A frequently used oral dosage is ____ mg/kg/day of L-carnitine for young children
and 1-2 grams/day of L-carnitine for older children and adults.

Back 235

100

Front 236

A frequently used intravenous dosage is __-__ mg/kg/day with a maximum dosage
of 100 mg/day.

Back 236

10-20

Front 237

Carnitine is an absolute requirement for the transport of ____ - chain fatty acids into
the mitochondrial matrix.

Back 237

long

Front 238

Carnitine ____ (is, is not) required for transport of medium-chain fatty acids in the
liver.

Back 238

is not

Front 239

Carnitine ______ (does, does not) stimulate medium-chain fatty acid oxidation in
skeletal muscles.

Back 239

does

Front 240

L-carnitine increases the _________ (oxidation, reduction) of branched-chain 2-oxoacids
derived from leucine and valine.

Back 240

oxidation

Front 241

The _________ contains the highest concentration of carnitine.

Back 241

epididymis

Front 242

Skeletal muscle and cardiac muscle also contain high concentrations of carnitine but
cannot _________ (synthesize, catabolize) carnitine.

Back 242

synthesize

Front 243

Carnitine may be used to detoxify an ____ drug or an _____ metabolite of a drug.

Back 243

acyl

Front 244

Two different nascent pools of carnitine are ________ and ____ ______ ____.

Back 244

plasma and red blood cell

Front 245

________ (liver, renal) excretion is the main excretory route for carnitine.

Back 245

Renal

Front 246

Anemia may be improved as a result of carnitine’s action on the repair of RBC
_________.

Back 246

membranes

Front 247

Carnitine delivers substrate, eliminates accumulated toxin and transports high energy
through its transport of ____________ acids across membranes.

Back 247

carboxylic