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Flashcards in Chemistry Deck (46)
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1

What is the function of cystatin C

Measure GFR
*Endogenous substances used to determine GFR are urea nitrogen, creatinine and cystatin C

2

Pt has low serum cholinesterase level--what is next step in workup?

Test if cholinesterase can be inhibited by dubicaine
**In hereditary hypocholinesterasemia, cholinesterase will not be inhibited by dubicaine

3

Most common drug to cause drug-induced lupus?

procainamide

4

Which lipid tests are invalid if patient is not fasting?

triglycerides and calculated LDL

5

Where is DHEA-S produced?

adrenals

6

What type of bilirubin is water insoluble and bound to albumin in blood?

Unconjugated (indirect)

7

What type of bilirubin is water soluble?

conjugated (direct)

8

4 diagnostic criteria for DM

HbA1c >6.5%
FPG >126
OGTT 2 hr >= 200 (75g ora glucose load)
Random plasma glucose >=200

9

Which patients have macro CK type 1?

healthy elderly women

10

Which patients have mitochondrial CK (macro-ck type 2)?

advanced malignancy

11

What does prealbumin bind in the serum?

thyroxine (aka transthyretin)
retinol binding protein: vitamin A complex

12

Causes of pseudo M-spike on SPEP?

Fibrinogen (incompletely clotted sample
hemoglobin (hemolyzed sample)
elevated CRP
elevated transferrin (beta area)
Medicaitons (antibiotics, radiocontrast agents)
Serum tumor markers (e.g. CA 19-9)

13

Define type 1 cryoglobulin

monoclonal immune globulin associated with MM or waldenstrom

14

Define type 2 cryoglobulin

mixture of monoclonal IgM and polyclonal IgG; IgM has rheumatoid factor activity (anti-IgG)
-most common type

15

Define type 3 cyroglobulin

mix of two polyclonal Ig's, typically IgG and IgM; IgM has rheumatoid factor activity

16

What is the most common cause of mixed cryoglobulinemia (type 2+3)

HCV
Sx include leukocytoclastic vasculitis, arthralgia, LAD hepatosplenomegaly, anemia, sensorineural hearing deficits, MPGN type II

17

what medical conditions can cause pseudohyponatremia?

hypertriglyceridemia
hypercholesterolemia
hyperproteinemia
(due to decreased water content of plasma)

18

What cancers can secrete PTHrp?

SCC lung, head and neck, skin ,cervix and esophagus
breast ca
T cell lymphoma

19

What forms of PTH are biologically active?

intact PTH
N-terminal PTH
-rapidly cleared from blood T1/2=5 mins

20

What is cause of increased BUN/creatinine ratio?

normal 10:1, if greater than 20:1 prerenal azotemia (due to hypoperfusion)

21

Most common cause of false pos b-hCG

heterophile antibodies

22

Quad screen showing low AFP, low uE, raised hCG and raised DIA

Trisomy 21 (Downs)

23

Quad screen showing low AFP, hCG and uE

Trisomy 18 (edwards)

24

Quad screen showing elevated AFP, normal hCG and low uE

NTD

25

What is metabolite of serotonin (5-HT) that is produced by carcinoids?

5 hydroxyindoleacetic acid (5-HIAA)
excreted in urine

26

What do foregut carcinoids produce?

histamine, catecholamines, 5 hydroxytryptophan (5-HTP)

27

What do midgut carcinoids produce?

serotonin only

28

What do hindgut carcinoids produce?

usually nothing! non-secretory

29

VMA is a metabolite of what

norepi-->normetanephrine-->vanillylmandelic acid (VMA)
epi-->metanephrine-->VMA

30

What two metabolites are elevated in neuroblastoma?

VMA and HVA (homovanillic acid; final breakdown product of dopamine)