Final Exam Flashcards
(184 cards)
1
Q
Acute Coronary Syndrome
A
sudden cardiac disorder which is irreversible
varies from angina, unstable angina, myocardial infarction
2
Q
Acute Myocardial Infarction
A
acute obstruction of blood circulation (ischemia) to a region of the heart muscle, resulting in myocardial injury and necrosis (>1 cm)
3
Q
this results in shortage of oxygen required for cell metabolism
A
ischemia
4
Q
most common cause of AMI
A
atherosclerosis
- plaque develops in the wall of the artery
- plaque builds up
- plaque ruptures
- clot forms around rupture = blocking blood flow =lack of O2 and nutrients to myocardium = cell death
5
Q
Troponin T
A
binds to tropomyosin and thin filament anchor of troponin complex
- found in cardiac muscle and regenerating skeletal muscle
6
Q
Troponin C
A
binds Ca2+ to produce conformational change in troponin I subunit
- found in cardiac and striated skeletal muscle
7
Q
Troponin I
A
binds to actin ONLY in cardiac muscle
- key regulator of cardiac muscle contraction/relaxation
8
Q
actin
A
involved in muscle contraction
9
Q
tropomyosin
A
regulate actin function
10
Q
_____ & ______ are considered cardiac-specific targets in diagnostic tests for cardiac muscle damage
A
only cTn I and cTn T
- troponin I and T
11
Q
when myocardial cells die, this is releaed
A
cardiac troponin cTn
12
Q
depending on the type of MI, cTn levels reach their maximum between…
A
6 hours and 3 days and then start to decline
13
Q
symptoms of AMI in men
A
- chest discomfort or pressure
- central chest pain -> arms, neck and/or jaw
- shortness of breath, coughing/wheezing
- unexplained fatigue, anxiety
- less common = light-headed/dizzy, nausea/vomiting, sweating
14
Q
symptoms of AMI in women
A
more non-chest pain symptoms
- mild discomfort in chest/achy or heavy feeling in the chest
- upper body discomfort
- feeling of bad indigestion, nausea
- shortness of breath
- extreme fatigue, sweating
- light-headed/dizzy, fainting
15
Q
roles of hs-cTn
A
- allows more rapid diagnosis and treatment of AMI
- potential use in assessing risk of CV events in the general population
- population reference ranges may allow differential diagnosis of AMI in biological males and females
16
Q
CK-MB and MB (myoglobin)
A
- past cTnI and cTnT assays
- CK-MB = measurable for the same or later time than troponin; less sensitive (smaller elevation) than troponin N w/ 48 hr; not specific to cardiac damage
- MB = measurable for a much shorter period than troponin; less sensitive (much smaller elevation) than troponin; not specific to cardiac damage
17
Q
symptoms of <3 failure
A
- difficult breathing
- dry, hacking cough
- swollen ankles, legs, abdomen
- rapid weight gain
- dizziness, fatigue, weakness
- decreased ability to exercise
- rapid or irregular heart beat
- increased need to urinate at night
- stomach bloating
- lack of appetite or nausea
18
Q
what is <3 failure?
A
- heart is weakened/damaged and cannot pump blood effectively during increased activity or stress
19
Q
reduces blood pressure and cardiac output
A
BNP (brain natriuretic peptide)
20
Q
left ventricle wall stress
A
release of Pro-BNP and its de novo synthesis
21
Q
where is NT-proBNP cleaved to its active form?
A
in peripheral circulation
22
Q
what does BNP do?
A
interacts with natriuretic peptide receptor A
- natriuresis/diuresis
- peripheral vasodilation
- inhibition of RAAS
- inhibition of sympathetic nervous system
23
Q
blood BNP correlates with…
A
severity of congestive heart failure
24
Q
BNP can be elevated in other conditions (besides CHF)
A
- valvular heart disease
- atrial fibrillation
- myocarditis
- acute coronary syndrome
- cardiac surgery
- congenital heart disease
- advancing age
- pulmonary hypertension
- sleep apnea
- critical illness
- sepsis
- burns
- renal failure
25
factors affecting test results in a BNP & NT-proBNP immunoassay
- heterophile Abs
- biotin interference (supplements!)
- ALP-related signal interference
- patient's comorbidities
- administered meds
26
should we measure BNP or NT-proBNP
- both have similar sensitivity and excellent specificity for CHF
- both have excellent precision
- values are BOT interchangeable (no conversion factor)
- both tests affected by: kidney function, age, sex
- in-vitro stability (NT-proBNP stable without additives in whole blood for 72 hrs); both stable during freeze/thaw process
27
multi-focal chronic vascular disease that underlies the cause of CV disorders
atherosclerosis
- heart: coronary heart disease (heart attack)
- brain: cerebrovascular disease (stroke)
- periphery: peripheral vascular disease (amputation)
28
this is characterized by fibro-inflammatory lipid plaque in arteries (occurs only in arteries)
atherosclerosis
- reduces blood vessel elasticity
- reduces blood flow
- can rupture, travel, and lodge in smaller blood vessels and block blood flow
29
major form of fat in nature
triglycerides
30
triglycerides
- storage form of fatty acids
- fatty acids used for E production & synthesis of phospholipids, cholesterols, esters, etc.
- fatty acid structures = saturated vs. cis-unsaturated vs. trans-unsaturated
31
phospholipids
two fatty acid chains and a phosphorous-containing group are attached to the glycerol backbone
- for cell signalling
- structures = membranes, lipoproteins
32
cholesterol
interlocking hydrocarbon rings from a steroid
- structures = membranes, lipoproteins
- steroid precursor of = bile acids (solubilize for digestion)
- steroid hormones (androgens, estrogens, progesterone, adrenocortical hormones)
33
core and coat of lipoproteins
coat: phospholipid, unesterified cholesterol, apoproteins
core: triglycerides and cholesterol esters
34
apoproteins
- top of lipoprotein structure
- activate enzymes involved in lipid metabolism
- maintain structural integrity of lipid-protein complex
- deliver lipids to cells upon recgonition by cell surface receptors
35
exogenous pathway of lipoprotein metabolism
CM; metrabolism of lipoproteins produced by intestine form dietary lipids
36
endogenous pathway of lipoproteins
VLDL, IDL, LDL
- metabolism of lipoproteins produced by the liver
- delivery of lipids to tissues forward lipid transport (FLT)
37
reverse cholesterol transport lipoprotein metabolism
HDL
| - removal of free cholesterol from peripheral tissues
38
these protect against CHD
HDLs
- remove cholesterol from periphery to liver
- antioxidant properties, inhibit platelet activation
- increase HDL by 1% decreases coronary risks by 2-3%
- increase HDL with decrease LDL leads to stabilization of plaque and eventual regression
39
Xanthomas
- deposition of lipid in skin, eyes
| - common symptoms of hyperlidemias
40
Apoprotein measurements
immunoassay
- turbidimetry, nephelometry
- ELISA (apo-A, apo-B)
41
most accurate way to measure HDL
ultracentrifugation
42
chemical preparation for HDL cholesterol for ultracentrifugation
- routine method
| - use polyanion/divalent cation (heparin/Mg 2+)
43
measuring indirect LDL cholesterol
- Friedwald formula
- assumes all cholesterol is VLDL, LDL, and HDL
- CM usually low in fasting subjects
- IDL and VLDL usually insignificant cntributors to toal cholesterol
- [LDL cholesterol] = [total chol] - [HDL chol] - TG/2.2
note: non-fasting speciman may have CM when TG> 4.0 mmol/L = ? presence of CM or CM remnants
44
direct LDL cholesterol
- newer methods precipitat VLDL, IDL, and HDL with polyvalent Abs to apo-A & apo-E
> LDL almost exclusively apo-B100
- may be less accurate if TG is very high; small dense LDL are present
45
non-HDL cholesterol
- new alternate target, like apo-B, to LDL-C in canadian lipid guidelines
- sum of all cholesterol transported in atherogenic lipoproteins, regardless of [TG]
- high predictive value of CV risk
- non-HDL-C = [total chol] - [HDL chol]
46
high sensitivity C-reactive protein
- acute phase reactant
- positively correlated with risk of future CHD events
- strong preictor of: IM, stroke, peripheral vascular disease, sudden cardiac death
47
Removes and breaks down triglycerides from chylomicrons
lipoprotein lipase
48
abetalipoprotenemia
no beta lipoprotein synthesis
49
hypoalphaproteinemia
defective apoA1 synthesis
50
hypoalphaproteinemia
defective apoA1 catabolism
51
medical diagnostic testing performed outside the cinical lab, in close proximity t where the patient is receiving care
point of care testing (POCT)
52
POCT has the potential to... (in hospital setting)
1. speed up diagnosis and timely management
2. reduce iatrognic anemia
3. reduce short- and long-term complications
4. reduce overall length of stay
5. improve workflow and resource utilization
53
POCT has the potential to... (in community setting)
1. speed up diagnosis and timely management
2. increase compliance with treatment requirements
3. promote healthier lifestyle choices
4. improve long-term outcomes
5. reduce the number of clinic visits
54
limitations of POCT
- limited test menu
- usually (but not always) the more expensive option or patient testing
- often (but not always) results are less accurate
- sometimes appears decetively simple
- harder to enforce compliance with regulations
- hidden costs
- may require clinical workflow modifictions to be an effective solution
55
theoretical plates
effective number of times a chemical distributes between the mobile and stationary phas as it moves through the system
56
great way to imrove the separation of peaks in a sample
increasing column length
57
approaches to imrprove resolution
1. increase column efficiency: reduce width at peak baseline
2. increase column selectivity: increase peak separation
3. increase degree of column retention by increasing tR using a mobile phase thast is a weaker solven for analyte of interest
58
void time (tM)
time to elute non-retained molecules
59
T or F. the carrier gas in gas chromatography does not interact with volatile samples
T!
| low density inert gasL usually nitrogen, helium, argon, hydrogen
60
gas chromatography sample separation is based on
differences in vapour pressure and interactions with the stationary phase
61
gas chromatography retention time depends on
- support SA
- pore size (if using polymer kind of support)
- functional groups
62
what is sample derivization?
for gas chromatography
| - if samples are not sufficiently volatile or thermally unstable = often modify polar groups
63
what is headspace analysis?
analyze the vapour above the sample if they have non-volatile saple
64
what is headspace analysis?
analyze the vapour above the sample if they have non-volatile samples
65
sample derivization methods
- replace active H with trimethylsilyl group (TMS)
- alkylation by addition of a methyl ester
- acylation to produce an acetate derivative
66
interactions in GC when they have similar polarity
interactions increase at the same temperature!
| - polar sample and polar liquid = increase in tR
67
high temperatures in GC
short tR but poor separation
| - temperature gradients giv the best separation (account for bp and polarity)
68
carrier gas flow rate for GC
- high flow rate decreases interaction of components with stationary phase
=> reduces retention time
=> poor separation of sample components
- optimal flow rate ensures reroducible tR
69
T or F. peak broadening is inversely proportional to flow rate
T! peaks broaden (molecule travelling in all directions; increase in tR) with decreased flow rate
70
what is gas-liquid chromatography column bleed?
liquid coating on support eventually leaves column!
| => noisy/high background signaldetected; decreased chemical retention
71
how to minimize column bleed?
minimize by using a bonded stationary phase instea (chemically-bonded to support)
-> bonded-phase GC
- polysiloxane: amount and typ of sid-chains (R gorups) affedcting chemical tR
72
before use, any column or GC must be ...
thermally conditioned
| - heat at various temps to remove volatile contaminants => unstable baselines
73
isothermal
- GC
- constant temp over time
- faster for samples with less variety of chemicals with different volatlities
74
varied temp over time (vs. isothermal in GC)
programmed
- weak interactions (low bp) elute first
- strongest interactions (highest bp) elute last
- sharper peaks in less time
75
the _____ of mobile phase in liquid chromatography is used to adjust retention time
composition
- strong mobile phase: leads to weak analyte on the stationary phase; analyte prefers mobile phase
- weak mobile phase: leads to highest retention of analyte on the stationary phase; analyte prefers stationary phase
76
ion-exchange chromatography
ions separated by adsorption to solid support with fixed charges at surface
depends on:
- pH
- type of competing ion
- type of fixed charge on the stationary phase
- density of fixed charge on the support
77
size exclusion chromatgraphy
- stationary phase based on physical differences not chemical
- mobile phase has no weak or strong phase; determined by analyte solubility and stability, support and column
78
porous with inert surface and range if pore sizes similar to analytes of interest; cross-linked dextran or agarose, polyacrylamide gel, modified silica or glass beads
size exclusion chromatography
79
this chromatography is used to identify intact complexes: lipoproteins, Ag-Ab complexes
SEC
80
affinity chromatography separaton by retention of analytes based on...
selective reversible biologically related interactions
| - Ag-Ab, enzyme-substrate, enzyme-inhibitor
81
ths type of cromatography has two different mobile phases to accomplish separation; one soid support
affinity chromatography
82
method of choice for most routine searation and analysis methods
HPLC (high [perfermonace liquid chromatography)
83
this uses more efficient psupports than original LC methods
HPLC
- narrower peak
- better separation
- lower limits of detection
84
this has to be "sparged"
HPLC solvent reservoir; to remove dissolved air bc it interferes w detector response
85
sample injector
reproducible, no carry-over, range of volumes
86
isocratic elution
same mobile phase throughout
87
gradient elution
mobile phase composition is varied overtime to control separation
- achieved through solvent programming
- start with weak mobile phase (allow weak retention to interact)
- profress to stronger mobile phase (elute chemicals with moderate/high retention)
88
glycation of Hb
- glucose enters RBC and naturally binds or glycates HbA1
| - this increases neg charge and changes in Hb size
89
this is measured for effectie monitoring of long-term glucose control in individuals with diabetes mellitus
% HbA1c
90
screening method for detection and preliminary identification of hemoglobinopathies
HPLC or capillary electrophoresis
91
accurate mass
experimentally determined mass
| - value obtained from mass spec m/z ratio
92
molecular mass
calculated mass of a compound based on the weighted average of the masses of all isotypes of the elements present; AKA average mass
93
the calculated mass based in the accuratre masses of the most abundant stable isotopes of the elements present
monoisotopic mass
94
the nearest integer value of the monoisotopic mass
nominal mass
95
components of mass spec
inlet system, ion source, mass analyzer, detector, data system
96
a plot of the intensities of the ions as a function of their m/z values
mass spectrum
97
this relies on adjusting RF and DC voltages to allow ions to pass through based on m/z
quadrupole
98
the principle is based on speed of ions relative to their mass; lighter ions are accelerated to a higher velocity than heavier ions
time of flight
99
ability of mass spec to detect an ion; how small an amount can be analyzed
sensitivity
100
measure of the ability of analyzer to separate ions with different m/z values + how sharply defined are the peaks, how separated are they from each other?
mass resolution
101
determines the abundance of the ions of different m/z after they have been separated by the mass analyzer
ion detector
102
ion detector characteristics
- low or no noise
- high stability
- simultaneous detection
- wide mass-range response
- mass-independent response
- fast response
- short recovery time
- high saturation level
103
what is a tandem mass spec?
2 mass analyzers (in space)
| - tandem in time = one mass analyzer ONLY
104
characteristics of a single mass analyzer
- see all m/z in a scan
- look for unknowns
- BUT high potential for overlapping m/z
- BUT poor specificity
105
characteristics of a tandem mass analyzer
- choose a specific target m/z
- fragments in collision cell and scans fragment ions
- good specificity due to fragmentation
**can generate structural info**
106
this is a chemical propert of proteins
absorb UV light
107
UV absorption at 280 nm
aromatic rings in amino acids
| - direct spec
108
disadvantages of direct spec
- depends on amino acid composition
| - uric acid and bilirubin interfere at 280 nm
109
UV absorption at 200-225 nm
- wavelength max for peptide bonds
- 10-30 x higher absorptivity than 280 nm
- disadvantages = interference at <220 nm
- remove rea (low MW)
110
this test is for serum test protein only
biuret test
111
disadvantage of biuret test
- cannot measure low protein levels so not useful for CSF or urine samples
112
Lowry or BCA
- for serum, CSF, and urine total protein
- modifications to Biuret method (to be more sensitive to lower conctns)
- most versatility for detecting different sample types
113
dye-binding
- based on chemical charge
- anionic dyes bind to cationic group of basic amino acids (histidine, arginine, lysine) & free AA terminal groups
- for urine, CSF total protein
114
turbidity & nephelometry
- chemical precipitation
- use trichoroacetic acid (TCA) or sulfosalicylic acid (SSA) to precipitate protein to prepare an insoluble protein suspension
- more sensitive than dye-binding
- for urine total protein
115
turbidimetry
- measures reduction of light which passes through cuvet
- transmitted at 180 degree angle
- detection limit is 20-30 microgram/mL
116
nephelometry
- measures scattered light
- at right angle (90 degrees) or forward angle
- detection limit is ~10 microgram/mL
- better than turbidimetry bc no interference from scattered light
117
reduced total protein (4)
- inadequate protein intake: malabsorption, malnutrition
- inadequate synthesis: chronic liver disease
- protein loss: nephrotic syndrome, diarrhea, severe burn
- dilution (IV line); artificial way to lose protein
118
elevated total protein (2)
- decreased blood volume: dehydration (FIRST thing u think about; proteins are not truly high, just seems this way bc lower blood volume)
- increased protein production: multiple myeloma, lupus, rheumatoid arthritis, other collagen diseases, chronic infections, sarcoidosis
119
bisalbuminemia
- genetic variant
- hereditary mutation
- no associated pathology
- fast and slow variants
120
causes of hypoalbulinemia
- malnutrition, inflammation
- liver, kidney, and GI disease
- pregnancy
121
what is albumin?
- negative acute-phase protein
- maintains oncotic pressure
- carrier protein
122
most abundant protein in serum
albumin
| - anionic protein
123
total serum protein = ?
albumin + serum globulins + other serum proteins
124
how to measure specific proteins
- immunoprecipitation (aggregation of immune complexes; Ag:Ab)
- ex: haptoglobin, transferrin, alpha1antitrypsin, complement
- specific proteins in sample combine with their specific Abs in the reagent = insoluble complexes
- aggregates increase turbidity and light scattering is proportional to [protein]
125
measuring total albumin
- ~60% of serum protein
- binds anionic dye bromocresol green or purple dye
- read within 30 s because not specific
126
how do enzymes accelerate a chemical rxn?
by lowering the activation E required for the reaction to occur to form P
127
where regulator molecules can bind on an enzyme
allosteric site; unlike the active site, not all enzymes have this
128
T or F. enzymes alter the final rxn equilibrium
F! they don't
129
this describes the relationship between velocity of enzyme reaction and [S]
Michaelis-Mentn (M-M)
| V = Vmax [S] / Km + [S]
130
What is Km?
[S] at 1/2 Vmax
- describes E affinity for S
- M-M constant specific for E and S
131
What is Vmax?
maximum rxn velocity
132
[S] must be __ Km to ensure detection of maximal E activity
>20x Km
133
what does low Km mean?
high affinity of enzyme for S!
134
factors affecting rate of ALL enzyme reactions (potential sources of assay error)
- substrate concentration
- enzyme concentration
- pH
- temperature
135
1st order kinetics
- V proportional to [S]
- enzyme readily binds at low [S]
- velocity proportional to [S]
- if [S] <20x Km, S depletes and enzyme rxn velocity decreases (linearity falls off)
- enzyme activity underestimated
- dependent on [S]
136
0 order kinetics
- V proportional to [E]
- no further addition of S will increase enzyme activity
- [S] > 20 Km ensures max rxn rate
- detect max E activity, independent of [S]
137
effect of enzyme concentration at fixed [S]
- at low [E], reaction rate (v) is proportional to [E]
| - if [E] > [S], rxn velocity will become non-linear, results will be invalid
138
Quality management system ensures: (5)
- correct sample collected from correct patient using correct methods
- specimens/samples transported properly to correct location
- correct test performed on correct sample
- ensure only valid results are reported (QC to assess test performance)
- results are reported in a timely manner
139
how is test interpretation done in a clinical diagnostic lab?
by comparing the patient result with the relevant set of reference values, known as a "Reference Range" or "Reference Interval" or "Reference Values"
140
diagnostic performance of a lab is measured by
- diagnostic sensitivity
| - diagnostic specifcity
141
diagnostic performance of a lab depends on:
- reference interval selection
| - degree of separation between healthy and diseased populations
142
range (interval) of values of a physiological measurement in a defined population of individuals
reference range/interval
143
when is AST ordered?
to detect liver damage/distinguish damafe to liver vs other tissues
144
when is ALT ordered?
to screen for liver damage (parenchymal cells)
145
clinical significance of increased serum AST
```
- viral hepatitis (100x when acute)
> AST rises before sign and symptoms appear
- cirrhosis (due to alcohol)
- myocardial infarct
- muscular dystrophy
- strenuous exercise, drugs
- NOT EXCLUSIVE TO LIVER DAMAGE
```
146
phosphatases
ALP and 5'-NT
147
when is ALP ordered?
to screen or monitor treatment of liver or bone disorder
148
clinical significance of increased ALP
- bone disease: Paget's disease, rickets, osteosarcoma, etc.
- hepatobiliary dsease: hepatitis; extrahepatic biliary tract obstruction
- placental ALP, Regan isoE, Nagao isoE (tumors)
149
when is 5'-NT ordered?
suspected biliary obstruction
150
clnical significance of increased 5'-NT
- diagnostic for biliary obstructive jaundice (cholestasis); persists longer than ALP
- destruction of liver cells
> higher with viral hepatitis > alcoholic liver disease, liver cirrhosis
> liver tumor
> use of liver-damaging drugs
151
GGT assay
gamma-glutamyl-p-nitroanalide + glycyglycine
152
when is GGT ordered?
- to differentiate between bone or liver cause of increased ALP
- to detect liver disease and/or alcohol abuse
153
clinical significance of increased GGT
- hepatobiliary disease
> biliary tract obstruction (Increase 5-30 x)
> choleostasis, pancreatitis, neoplasms
> hepatitis
- drugs that induce microsomal enzymes
> warfarin, phenobarbitol, phenytoin, rifampicin
> alcohollll: remains increased even after 3-4 weeks abstinence
154
T or F. GGT is more sensitive and persists longer than other enzymes
T!
| - also, GGT assays differentiates source of increased ALP
155
phosphatases
```
can transfer (R2-O-PO3)
or hydrolyse (making a PO4, ROH) a phosphate gorup
```
156
If you have too much product accumulating, can cause _________ of a rxn
inhibition
- ALP inhibited by phosphate
- adenosine inhibits 5'NT if AMP + H2O
157
Glutathione
involved in tissue building and repair, making chemicals and proteins needed in the body, and in immune system function.
158
Amylase
- digestion of starch to glucse, maltose, dextrins
- only alpha -1,4 linkage (glycosidic bond)
- acinar cells (pancreas and salivary glands)
- isoenzymes P & S
- low MW so appears in urine
159
when is AMS (amylase ordered?)
to monitor/diagnose pancreatic disease
160
increase in AMS
- acute pancreatitis (increase >10X is diagnostic but also with non-pancreatic tumors)
- magnitude of increase not correlated with severuty
- urine AMS is more frequently elevated
> reches higher levels and persists longer
160
increase in AMS
- acute pancreatitis (increase >10X is diagnostic but also with non-pancreatic tumors)
- magnitude of increase not correlated with severuty
- urine AMS is more frequently elevated
> reches higher levels and persists longer
161
T or F. 20% of patientrs with acute pancreatitis have normal AMS activity
T!
162
AMS has good _____ but poor _______
good sensitivity but poor specificity
163
why is it difficult to diagnose increase AMS when less than 10X?
could be due to:
- renal fdailure
- diabetic ketoacidosis
- GI disorders or obstruction
- viral infection (mumps, AIDS)
- acute alcoholism
- drugs
164
progressive decrease in AMS
- chronic pancreatitis
- cells destroyed
> alcoholism, trauma, obstruction, CF
165
hydrolysis of dietary triglycerdes at 1 and 3 positions
lipase (LIP)
166
where are LIPs located
pancreas 100x > other tissues
| - isoenzymes L1 and L2
167
this inhibits LPS
Hb (avoid hemolysis in Lipase assays)
168
when is lipase ordered?
to monitor or diagnose pancreatic disease
169
increase in LIP significance
- acute pancreatitis
> more specific than AMS (stays high longer)
> differentiates increase serum AMS
- following biliary tract endoscopy
- morphine
170
decrease in LIP significance
- permanent change to pancreatic cells
- risk of developing diabetes
- risk inability to digest fats (greasy stool)
- progressive disease => irreversible damage => death
171
trypsinogen immunoassay
- ImmunoReactive Trypsin (RT)
| - blood, serum, plasma
172
trypsin catalytic assay
- synthetic peptide substrates
| - stool, duodenal fluid
173
when is trypsin ordered?
to screen for cystic fibrosis and pancreatic insufficiency
174
clinical significance of decreased trypsin
- decrease stool = CF
| - decrease plasma IRT = pancreatic insufficiency, diabetes
175
clinical significance of increased trypsin
increased plasma IRT
- acute pancreatitis
- neonates with CF
- chronic renal failure
176
acetylcholinesterase
- true cholinesterase (I)
- hydrolyzes acetylcholine to terminate depolarization of post-synaptic muscle cell
- RBC, lung, spleen, nerves, brain gray matter
177
Pseudocholinesterase
- CHE, (II), serum or butyryl cholinesterase
- unknown role, synthesized in liver
- liver, plasma, pancreas, heart, brain white matter
- genetic variants = decrease activity against choline esters; clinicall useful
178
when is cholinesterase ordered?
to detect exposure to pesticides or inherited CHE deficiency; test liver function
179
significance of decased CHE activity
- insecticide poisoning
- atypical CHE variant = fails to destroy muscle relaxant (succinylcholine) used in surgery = prolonges paralysis of resp muscle
- reduced liver synthetic capacity = acute hepatitis, adv. cirrhosis and cancer
180
creatine kinase
- energy storage in muscle
| - brain, heart, striated muscle (very low in liver and RBC)
181
why must we protect the SH groups of CK active site?
CK inactivated by heat, sunlight, increase in pH
182
when is CK ordered?
to detect muscle damage
183
increase CK significance
- muscular dystrophy or MD (CK-3); Duchenne's MD (CK-2, CK-3)
- damage to blood-brain barrier (CK-1)
- acute MI (NOT SPECIFIC)
