Electrolytes: Magnesium

Question 1

Methodologies
1. ______________ (________ and _________)
-a naphthol sulfonic acid derivative
-uses ________________________
-Mg+ + Calgamite –> ____________ (_________ nm)
-__________________ - masks effect of calcium
-t_________________ - masks effect of iron

2. Formazan dye (_________)
   -Mg2+ + Dye + Colored Complex _______nm)
3. _________________________ (__________, ___________)
   -Mg2+ + Chromogen –> Colored Complex
4. ____________/_______________ Yellow, _____________Yellow
   -Mg + Titan Yellow –> ______________ colloidal ppt
   -_______________________ –> to increase sensitivity
5. _________________________
   -Mg + 8-hydroxy-5-quinoline sulfonic acid –> Fluorescence (380-410 nm)
6. __________________________________
   -reference method for magnesium
7. ___________________________

Answer 1

1. Calgamite (Hitachi and Synchron)
   - polyvinylpyrrolidone
   - Reddish violet (520-532 nm)
   -strontium chelate
   -triethanolamine
2. Formazan dye (Vitros)
   -660nm
3. Methylthymol blue (Dimension, DuPont aca)
4. Titan Yellow/Dry Lake Method/Clayton Yellow/Thiazole Yellow
   -Red Lake colloidal ppt
   -polyvinyl alcohol
5. Fluorometric Method
   -Fluorescence (380-410 nm)
6. Atomic Absorption Spectrophotometry
7. Ion-selective electro

Question 2

Magnesium
-_________ most abundant _______
-_______ most abundant______________
-_____ (Bone), ____ (muscle, soft tissues), _____ (Blood)
-majority is stored in _______ in complex pf calcium and phosphate
-an enzyme activator in ___________________
-3 forms in serum:
* Ionized (_______)
* Protein bound (_____)
* Complexed (_____)

Answer 2

4th most abundant cation
2nd most abundant intracellular cation
53%, 46%, <1%
bone
ATPase ion pumps
60-70%
30%
5%

Question 3

Functions of Magnesium
* Important in maintaining structures of ______, ________, and __________
* Synthesis of _________ and ______
* Cofactor for___________, _____________, _________, and _________
* Contributor to _______ structure
* For ________________ and_______________
* ____________ to enzymatic reactions

Answer 3

DNA, RNA, ribosomes
proteins and lipds
phosphatase, kinase, phosphorylase, enolase
bone
muscle contraction and herth rhythm
activator

Question 4

Regulation of Magnesium
* ___________________________
-increases renal reabsorption of magnesium
-enhances intestinal reabsorption of magnesium

• ______________________________
  -increases renal excretion of magnesium

Answer 4

PTH
Aldosterone and Thyroxine

Question 5

Specimen Considerations and Patient Preparation
* ____________, _________________, _____________
* ________, _______, ________ - should not be used
* No to hemolysis -________________ (Mg is ___x greater in RBC)
* 24-hour Urine - acidified with _____ to avoid precipitation

Answer 5

serum, lithium heparinized plasma, 24-hr urine
oxalate, EDTA, citrate
false increase - 20x
HCl

Question 6

Values to Remember
* Reference Value: ________________
* Conversion Factor: mEq/L to mmol/L = ____

Answer 6

0.63-1.0 mmol/L
0.5