Ldh Flashcards

1
Q

Major tissue source of LDH

A

Heart
Erythrocytes
Liver
Kidney

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2
Q

LDH is found in small amount in

A

Smooth muscle
Brain
Lungs

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3
Q

Elevated surem levels of LDH id observed in (?)

A

Myocardial infarction
Liver disease
Renal disease
Certain forms of anemia
Malignant diseases
Progressive muscle dystrophy

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4
Q

Lactate and pyruvate offers a number of advantages such as

A

Better reagent stability
Elemintaion of pre-incubation in the procedure
Rate of reaction being linear to a wide range
Less contamination of NAD with inhibiting products

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5
Q

Catalyzes the oxidation of lactate to pyruvate in the presence of NAD

A

Lactate dehydrogenase

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6
Q

Wavelength of LDH

A

340 nm

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7
Q

Forward reaction pH of LDH

A

8.3 - 8.9

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8
Q

Reverse reaction pH of LDH

A

7.1 - 7.4

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9
Q

Advantages of reverse reaction

A

Small volume
Short incubation time

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10
Q

Disadvantages of reverse reaction

A

Prone to substrate exhaustion
Loss of linearity

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11
Q

LDH does not act on (?) and only (?) acts as the coenzyme

A

D-lactate
NAD

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12
Q

In lactate dehydrogenase reaction, the (?) formed will proceed to the (?) pathway for generation of energy

A

Pyruvate
Embden-meyerhoff pathway

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13
Q

With the oxidation of lactate to pyruvate, pyruvate and NADH are formed

A

Colorimetric method based on Wacker

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14
Q

In the Colorimetric method based on wacker, a mixture of (1) and (2) reacts with NADH to produce (3) colored compound

A

1 Phenazine methosulfate
2 nitroblue tetrazolium
3 Blue

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15
Q

conversion of pyruvate to lactate by LDH with the presence of NADH

A

Wroblewski and La due
pH 7.4 - 7.8

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16
Q

The rate of reverse reaction in wrobleski and la due is (?) times faster than forward reaction allowing (advantages)

A

three
smaller volume samples and Shorter reaction time

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17
Q

Methods for separation and quantitation of LDH isoenzyme

A

1 Electrophoresis
2 Column chromatography
3 Immuno-inhibition
4 Babson’s method
5 Kaplan and Berger
6 using alpha-hydroxybutyrate as a substrate

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18
Q

Separates isoenzyme based on their anodal rate of migration in an electrophoretic field

A

Electrophoresis

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19
Q

(LDH Isoenzyme)
Migrates the fastest in electrophoresis

A

LDH1

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20
Q

(LDH Isoenzyme)
Migrates the lowest in electrophoresis

A

LDH6

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21
Q

In electrophoresis, an LDH bound to immunoglobulin such as IgA and IgG migrate between (?)

A

LDH3 and LDH4

22
Q

Method employed for isolation of LDH1 and LDH2 for screening of AMI

A

Column chromatography

23
Q

Isoenzymes being isolated during the screening of AMI in column chromatography

A

LDH1 and LDH2

24
Q

Method used for the isolation of LDH1 (only)

A

Immuno-inhibition

25
Q

Only isoenzyme that does not contain the M subunit of LDH

A

LDH1

26
Q

Measures the ratio of LDH1 and LDH5

A

Babson’s method

27
Q

Inhibits the LDH1 in Babson’s method

A

M-lactate

28
Q

Inhibits the LDH5 in Babson’s method

A

M-lactate-1 M urea

29
Q

Involves the determination of LDH1 using the rate of heat production in a batch type of colorimeter

A

Kaplan and Berger

30
Q

In alpha-hydroxybutyrate, the (?) subunit has greater affinity than the other subunit

A

H

31
Q

Acute myocardial infarction
Rise: ?
Peak: ?
Elevated for: ?

A

R: within 12-24h
P: 48 - 72h
Ef: 10 days

32
Q

Highest concentration of LDH is observe in (conditions/disease)

A

Pernicious anemia
Megaloblastic anemia

33
Q

Increased LDH concentration is also observe in (conditions)

A

Cardiac, hepatic, skeletal muscle and renal disease

34
Q

The Subunits of LDH

A

H and M subunits

35
Q

Reagent composition of LDH

A

L-lithium lactate
Buffer (pH 9.0)

36
Q

LDH isoenzyme observe when patients is near death

A

LDH6

37
Q

LDH is determined by:
Mean abs difference/ min x (?)

A

6592

38
Q

What is the:
1 Number of absorbance readings in LDH?
2 trend of absorbance?

A

1 three
2 increasing

39
Q

Expected values: (30°C)
Males: (?)
Females: (?)

A

M: 50 - 166 U/L
F: 60 - 132 U/L

40
Q

Expected values: (37°C)
Males: (?)
Females: (?)

A

M: 80 - 285 U/L (37°C
F: 103 - 227 U/L (37°C)

41
Q

Linearity of LDH

A

800 U/L

42
Q

Preferred specimen

A

Fresh unhemolyzed serum

43
Q

Frozen samples show decreased activity of isoenzyme (?)

A

LD-4 and LD-5

44
Q

Inhibits LDH assay (Additives)

A

Heparin
Citrate
Oxalate

45
Q

Type of serum samples that require a serum blank

A

Icteric and lipemic samples

46
Q

Most heat stable LDH isoenzyme

A

LDH2

47
Q

Fastest LDH isoenzyme (anodal)

A

LDH1

48
Q

Most labile LDH isoenzyme

A

LDH5

49
Q

Intermediate LDH isoenzyme in terms of electrophoretic mobility

A

LDH3

50
Q

Most predominant LDH isoenzyme in the serum

A

LDH2