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Clinical Chem II spring > Porphyrins and Hgb > Flashcards

Porphyrins and Hgb Flashcards

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1
Q

Describe porphyrins
shape?
compromised of?
joined by?

A

cyclic structures compromised of 4 pyrole rings joined by methine bridges

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2
Q

chelation of ferrous iron

A

to protoporphyrin ring, creates heme

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3
Q

Heme

A

binds oxygen, is a prothestetic group

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4
Q

Porphyrias

A

disorders that result from distrubance in heme synthesis

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5
Q

Hgb molecules

A

bind/deliver/release oxygen

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6
Q

Hgbopathies

A

qualitative defects

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7
Q

Thalassemia

A

quantitative defects

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8
Q

Porphyrins
chemical intermediate in…
pigments called?

iron is chlated into?

excess?

A

Chemical intermediate in synth of hgb/mygb/respiratory pirgments called cytochromes

iron is chelated into porph ring

excess compounds

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9
Q

Porphyrionogens
reduced…
intermediates in…

what happens w exposure to air?

A

reduced compounds that are intermidiate in synth of heme

oxidized on exposure to air in porphyrins

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10
Q

Isomers
how many for every porphyrin compound?

what types occur naturally?

A

4 isomers for every porphyrin compound

type I and III naturally occur

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11
Q

Whats special about type III isomer?

A

only one to form heme

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12
Q

T/F in some disorders the non functional type I isomer may be found in excess body fluids and tissues

A

true

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13
Q

Porphyrin properties
photo……due to….
color due to?

aqueous sol varies with…..

A

photoactive due to conjugation w tetrapyrole ring

dark red color due to strong absorbance (600-650nm)

aqueous sol varies w # of carboxylic acid present in substance

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14
Q

Uroporphyrin (Uro)

A

8 carb groups, most soluble in H20 excreted renally

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15
Q

Coprophyrin (Copro)
how many carb groups
solubility?
in?

A

4 carb groups, interm sol

blood and urine/feces

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16
Q

porphyrin groups with 2 carbs
influences?

A

least soluble

influences type of specimen selected to measure

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17
Q

Synthesis of heme
all cells contain..
primary sites?

A

all cells contain hemoproteins and can synth heme

BM/Liver primary site

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18
Q

how many molecules of heme is produced from 8 molecules of Alpha ALA?

A

one molecule of heme produced

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19
Q

What synthetic rxn require energy?

A

First and last three (in mitochrondria) others in cytosol

negative feedback mechanism

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20
Q

Control rate of heme
where?
through regulation of?

increase in pool of hepatic heme?

decreased heme?

A

in liver

through regulation of ALAS

increase in pool of hepatic heme decrease ALAS pool

ALAS production increase decreases heme

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21
Q

In bone marrow what controls rate of heme synthesis?

A

erythrocytes and other enzymes in pathway

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22
Q

Disorders of bio heme synthesis
most are?

A

most auto dominannt with 50% reduction in activity or affected enzymes

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23
Q

Enzyme defects
excess accum….

A

excessive accumulation/excretion of intermediate compounds that produce symptoms

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24
Q

Neuopsychiatric symptoms

A

abdominal pain, nausea, constipation

excess in early precursors in oath of heme synth (ALA/PBG)

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25
Porph symptoms hint (a/a)
ADP/AIP
26
Cutaneous symptoms: p/b/f excess.... c/p/e/x increased fragility of light exposure in? burning of light exposed skin in? due to ?
sympt photosensitivity, blisters, facial hair excess porphyrin intermediates CEP,PCT,EPP,XLPP increased fragility of light exposure in CEP/PCT burning of light exposed skin in EPP/XLPP due to absorption of light of porhyrins
27
Neurocutaneous symptoms excess... h/v
excess precursors/intermediates HCP/VP
28
Acute porphyrias causes what kind of attacks? neruophyciatirc? neurocutaneous? most common?
neurological/serious acute attacks ADP/AIP - neurophychiatric HCP/VP - neurocutaneous AID - most common acute porphy, 80% asymptomatic
29
Non acute present as chronic (cutaneous) c/p/e/x most common? extreme photosensitivity
CEP,PCT,EPP,XLPP PCT most common CEP - extreme photosensitivty
30
Secondary Porphyious increased excretion of? caused by? examples that cause excess excretion/ inhereited?
increased excretion of urinary porphyrins caused by another disorder/toxin interferring w heme formation liver disease/lead posioning excess urinary porph excretion inherited disorder of bilirubin met
31
Acute porphyria testing determin what in urine? if positive?
Determin PBG in urine if positive - ID ALP, differentiate AIP/VP/MCP
32
Cutaneous porphyria testing measured in? increased excretion of porph pattern diagnostic for? .....in plasma and whole blood?
measure porh in random/timed urine increasse excretion of porph pattern in diagnostic for PCT/CEP EPP/XLPP is plasma and whole blod
33
Analytical methods wat H chrom Fec
watson-schwartz assay HPLC Chromotographic Fecal HPLC/flourecnese
34
Specimen requirements
protected from light unpreserved urine 4 degrees - 48 hr neg 20 for weeks fecal frozen 20 degrees whole blood EDTA protect from light 4 degrees
35
Hgb
oxy transport to tissues/CO2 back to lungs carried to all tissues of body by erythroctes major buffer systom of body
36
Hgb shape
spherical molecule 2 major parts, central oxy non protein molecule 2 glob chains, Alpha and beta
37
Majority of adults have what Hgb
Hgb A and A1 two alpha two beta Hgb A2 <3% (two alpha two delta) Hgb F (2 alpha 2 gamma)
38
Neonate hgb
Hgb F 2 alpha two gamma main hgb during fetal life and 60% of hgb at birth
39
Hgbopathies defined
defect in structures
40
Thalassemias defined
defect in rate and quant of production decreased or absent chains alpha and beta micro/hypo autodom hetero
41
what chromosome are Alpha genes? all others?
a genes on chrom 16 others 11
42
T/F in most people, the alpha gene is duplicated A1/A2 indentical alpha genes in Hgb A,A2 and F
ture
43
non alpha genes subject to ?
delta, beta, gamma subject to non homologous cross over fused/hybrid chains
44
hgb lepore : what type of chains Hgb kenya: chains?
delta beta chains kenya: gamma beta chains
45
Hgbopathies divided into groups based on?
based on genetics, 4 groups AA subsitutions AA deletions Elongated chains/frameshift (constant spring) Fused/hybrid chains
46
Most abnormalities are?
amino acid subsittutions 2/3 hgbopathies affect Beta chains
47
More on thalassemia absent/deminished?
absent/deminished synth of polypeptide chains alpha thal: no alpha chains ...etc
48
Synth and degradation of heme synth occurs in? normally requires synth in? glob synth in what supply?
hgb synth occures in immature rbcs/bone marrow norm synth requires synth in mitochonrida (heme) glob synth in cytoplasm iron supply
49
Intravascular vs extravascular
I: blood vessles E: cells/liver
50
Hgb S
most common in US sickle cell HbAS black/african population solubility test HGB S IS BETWEEN A AND A2
51
Hgb C
west africa/ghana target cells/crystals cellulose electrophor moves w Hgb A2 negative tube sol
52
Hgb SC
most common mixed hgb B-s/B chains no normal B chains to produce A tube sol postive
53
Hgb E Hgb D
asian microcytes somewhat unstable D: given to varient similar to S that is tube negative, homozygous rare, found in india
54
Thal minor
hetero, asymptom, iron deficiencies
55
Thal Major
lethal before birth, complications
56
Alpha thal chromosome? hydrops fetalis? hgb M? silent carriers? A thal trait?
chrom 16 4 genes hydrops fetalis: alpha chain absense, hgb barts Hgb M: mod heme anemia Silent carriers: missing 1 gene A thal trait: two gene deletion
57
Beta thal caused by? homozgous -.....causes? Hetero? B+ B0
caused by mutations homozygous - major - cooley anemia, crippling in childhood, bone deformities hetero - minor B+ reduced chains - most common severe B0 absent chains - dec hgb anemia
58
tube Solubility test fasle neg? false pos?
screen for sickle cells sickling hgb means you cant read through the tube (looks turbid) false neg due to transfusions/hgb F false pos: whole blood vs packed rbcs
59
Cellulose acetate
alkaline buffer electro mobility: AFSC universal screening for newborn hgb op
60
Other tests
citric agar, Hgb A2 quant, acid elution, Hgb F quant
61
DNA
increase sensititivy and specificity higher cost prental diagn of thal major
62
Myoglobin
skeletal/caridac muscle damage to muscles increase serum urine myoglobin rapid renal clearance - increase conc = renal failure can cause reaction like rhabdo/mI/Muscle dystrophy

Clinical Chem II spring (16 decks)

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