Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Renal I Midterm > Lecture 3: Nitrogen Metabolism > Flashcards

Lecture 3: Nitrogen Metabolism Flashcards

1
Q

Describe how calcium oxalate, uric acid, struvite, and cystine crystals are formed?

A

Calcium Oxalate: Hyperparathyroidism (Vit D, calcium, phosphate

Struvite: UTI’s (bacterial infection

Uric acid: Gout

Cystine: Cystinuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Who is the star of nitrogen flow in maintaining the bodies nitrogen balance?

A

Glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What enzymatic rxn is first step in Nitrogen removal?

A

Oxidative deanimation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which AA is the source of carbon skeleton for the Urea cycle?

A

Aspartate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Rate-limiting step of the urea cycle?

A

Conversion of ammonia to carbamoyl phosphate via carbamoyl phosphate synthetase I and NAG activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What part of the kidney is responsible for nitrogen sequestration?

A

Proximal convoluted tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is there a double whammy effect with IEM of AA resorption?

A

Affects the transporters in both the kidney and intestine causing malabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Hartnup disease is caused by an IEM affecting transporters of?

A

Neutral AA’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cystinuria is caused by an IEM affecting transporters of?

A

Dibasic AA’s - COAL

Cystine, lysine, arginine, ornithine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the most significant AA affected by Hartnup and why; what vitamin deficiency is commonly seen?

A
  • Tryptophan
  • Is a precursor for serotonin, melatonin, and niacin (NAD)
  • Therefore niacin deficiency is also noted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When does Hartnup disease manifest and what are Sx’s?

A
  • Infancy as failure to thrive
  • Nystagmus (rapid and repetitive eye movement)
  • Photosensitivity
  • Pellagra-like dermatosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What triggers Hartnup and what usually precedes an attack?

A
  • Sunlight, fever, drugs, or emotional/physical stress

- Poor nutrition almost ALWAYS precedes an attack

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Best Tx for Hartnup?

A

Niacin repletion (Vitamin B3)

*Think about how many important rxn pathways NAD is involved in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cystinuria patients usually present with

A
  • Renal colic (abdominal pain linked to the kidney stones)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ornithine deficiency caused by cystinuria is significant why?

A

Ornithine is a necessary substrate for the Urea Cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Classical PKU is caused by a deficiency in what enzyme needed for what rxn?

A
  • Phenylalanine hydroxylase

- Needed to convert Phe –> Tyr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Deficiency in Tyrosinase leads to decreased production of and what clinical manifestation?

A
  • Melanin

- Albinism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Secondary PKU is caused by deficiency in what enzyme?

A

Tetrahydrobiopterin (THB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dx of PKU must be made before what age?

A

Before the child is 2 weeks of age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Dietary Phe restriction is usually instituted if blood Phe levels are >?

A

> 360 µmol/dL

21
Q

Some pt’s with milder forms of PKU show increased tolerance to dietary proteins and improved metabolic control when treated with what; how much?

A
  • Tetrahydrobiopterin (THB)

- 5-20 mg/kg/day

22
Q

What is the common Tx for PKU

A
  • Limit dietary protein intake

- Supplement with Tyr

23
Q

Elevated levels of Tyrosine is caused by?

A

Tyrosinemias

24
Q

Tyrosinemia Type I pt’s excrete what problematic substance; what problems does it cause?

A
  • Succinylacetone
  • Toxic to liver and kidneys
  • Interferes with TCA cycle
  • Causes Renal Tubule dysfunction
  • Inhibits biosynthesis of Heme
25
Q

Tyrosinemia Type II is defect in what enzyme; causes?

A
  • Tyrosine aminotransferase

- Photophobia ad skin lesions on palms/soles

26
Q

Tyrosinemia Type III defect in what enzyme; causes?

A
  • p-hydroxyphenylpyruvate oxidase

- Intermittent ataxia

27
Q

Tyrosinemia’s are defects in the conversion of tyrosine to?

A
  • Fumarate

- All defects at different steps in the pathway

28
Q

What is the most common tyrosinemia and what medical intervention is typically required?

A
  • Type I

- Liver transplant

29
Q

What is the go-to Tx for Type I Tyrosinemia; prevents formation of?

A
  • Nitisinone, a p-hydroxyphenylpyruvate oxidase inhibitor

- Prevents formation of fumarylacetoacetate

30
Q

Alkaptonuria is also called what disease and is due to deficiency is what enzyme; what pathway?

A
  • Black urine disease or black bone disease

- Homogentisate oxidase (enzyme in the Tyr degradation pathway)

31
Q

What is commonly seen in the IV discs of alkaptonuria patients?

A

Black pigmentation in the IV discs

32
Q

What is the toxic agent produced by disorders of the urea cycle; why is it so toxic?

A
  • NH3 (ammonia)

- Non-charged so can readily diffuse through membranes of cell

33
Q

Primary vs. secondary hyperuricemia

A

Primary: overproduction of uric acid
Secondary: under-excretion of uric acid

34
Q

What kind of foods need to be avoided with Gout?

A

Diets rich in purines (beans, spinach, lentils) along with alcohol, meat and seafood can trigger episodes

35
Q

Gout is a problem that arises from the metabolism of what?

A

Purines!

36
Q

What is the X-linked inheritance disorder (outlier) of the Urea cycle, enzyme is involved, this disorder causes what?

A
  • Orotic aciduria
  • Ornithine transcarbamoylase
  • Causes excess carbamoyl phosphate to spill out into the cytoplasm, which is then metabolized by pyrimidine synthesis pathway to orotic acid which accumulates and is excreted in urine
37
Q

Defects in what transporters result in more severe hyperammonemia; what enzyme?

A
  • Mitochondrial transporters

- Carbamoyl phosphate synthetase I

38
Q

What is carbamoyl phosphate synthetase II involved in, where is it found, stimulated/inhibited by?

A
  • First step of de novo of pyrimidine synthesis
  • Cytosolic enzyme
  • Stimulated by PPPP, inhibited by UTP
39
Q

What is the difference in orotic aciduria caused by UMP synthase deficiencies?

A
  • Is NOT accompanied by hyperammonia or reduced BUN levels
40
Q

What is carbamoyl phosphate synthetase I involved, where is it found in cell and what activates it?

A
  • Rate-limiting step of Urea Cycle
  • Found in Mitochondria
  • Activated by NAG
41
Q

What is the difference between direct and indirect bilirubin?

A
  • Indirect is unconjugated and insoluble

- Direct is conjugated and water soluble

42
Q

What is a tx for jaundice?

A

Blue fluorescent light allows photochemical conversion of bilirubin to water-soluble isomers

43
Q

Which kind of cystals/stones must be surgically removed?

A

Struvite crystals

44
Q

What is the glucose related kidney disease; sx’s?

A

Fanconi-Bickel syndrome (d-Glucose)

  • Growth retardation, rickets, hepatorenal glycogenesis, and hypo- and hyperglycemia
45
Q

What can cause severe jaundice in newborns?

A
  • Sickle cell anemia
  • Rh or type incompatibility (hemolysis)
  • Cephalohematoma (traumatic birth)
  • Higher levels of RBC’s as seen in small-for-gestational age (SGA) babies
  • Enzymatic deficiencies
46
Q

Tx of Gout with Allopurinol does what?

A

Inhibits Xanthine Oxidase (enzyme) lowering the formation of uric acid. With an increase in excretion of hypoxanthine and xanthine. Decreasing the overall synthesis of Purines.

47
Q

Gout can result from a reduction in activity of what enzyme?

A

Glucose 6-phosphatase

48
Q

Bilirubin produced in neonatal jaundice lacks which carbohydrate?

A

Glucuronate - enhances the solubility of bilirubin

Renal I Midterm (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions