CC Lec Finals

Galactosemia

a congenital deficiency of one of the three enzymes involve in galactose metabolism

Galactosemia (2)`

cause by failure to thrive syndrome in infants?

1. Galactose-1-phosphate uridyl transferase (most common deficiency)

2. Galactokinase (GALK)

3. uridine diphosphate galactose-4-epimerase

(GALE)

Three enzyme are involved in this disorder?

Galactose-1-phosphate into glucose

What does Galactose-1- phosphate uridyl transferase convert?

Elevated blood and urine galactose

Laboratory Features of Galactosemia

○ Jaundice

○ Hepatomegaly

○ easy bruisability

○ Hypotonia

○ Galactosuria

○ E.coli sepsis

○ cataract

○ sensory neural deafness

Clinical Features of Galactosemia

Erythrocyte Galactose-1-phosphate uridyl transferase activity

Diagnostic test of Galactosemia

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Method used for Galactosemia

EDTA whole blood

Specimen for Galactosemia

Essential Fructosuria

autosomal recessive disorder characterized by fructokinase deficiency

fructose to fructose-1-phosphate

Fructokinase catalyzes the conversion of?

Fructosuria

Diagnostic indicator for Essential fructosuria

Hereditary Fructose Intolerance

a defect of fructose-1-6-biphosphate aldolase B activity in the liver, kidney, and intestine

• dihydroxyacetone phosphate

• glyceraldehydes-3-phosphate

• glyceraldehydes

Hereditary Fructose Intolerance is the inability to convert fructose -1- phosphate and fructose 1-6 biphosphate into what?

both hepatic glycogenolysis and gluconeogenesis, hence inducing hypoglycemia, and results in depletion of adenosine triphosphate

Accumulation of fructose-1-phosphate inhibits what?

Irritability, lethargy, seizures and hepatomegaly

Clinical features of Hereditary Fructose Intolerance

Fructose-1,6-biphosphate (FBP)

a defect in fructose-1,6-biphosphate which fails hepatic glucose generation by gluconeogenic precursors such as lactate and glycerol

Fructose-1,6-biphosphate

It is a key enzyme in gluconeogenesis

impaired formation of glucose from all gluconeogenic precursors, including dietary fructose, leading to fasting hypoglycaemia, ketosis and acidosis. Inheritance is autosomal recessive.

A deficiency of FBP results in an?

Glycogen Storage Disease (GSD)

An inherited autosomal recessive trait; a consequence of inherited deficiencies of enzymes that control the synthesis or breakdown of glycogen

An abnormal quality and quantity is found in the disorder

Types I, III, IV, VI, IX and 0

GSD causes liver damage such as?

Types V and VII

GSD causes muscular defect such as?

Muscle cramps, exercise intolerance, fatigue and weakness

Signs of liver glycogenesis?

Von-Gierke disease

the most common GSD it is associated with hyperlipedemia

Deficiencies of LDH, PK, phosphoglycerate kinase and mutase

What are the other GSD?

Intraveneous Galactose tolerance test — is used in the diagnosis of of type 1 GSD (glucose

levels)

The method used for GSD?

Serial blood specimen are collection are collected for 2 hours at 15 minute intervals

What is the procedure for the diagnosis of of type 1 GSD (Intraveneous Galactose tolerance test)?

Ia (Von Gierke)

Glucose-6-phosphatase

Ib

Glucose-6-phosphatase Translocase

II (Pompe)

1,4 Glucosidase

IIIa (Cori-Forbes)

De brancher or Amylo 1, 6 Glucosidase deficiency liver and muscle

IIIb

De brancher liver

IV (Andersen)

Brancher/Branding enzyme Deficiency

V (Mc. Ardle)

Muscle phosphorylase

VI (Hers)

Liver Phosphorylase / Phosphorylase kinase

VII (Tarui)

Muscle Fructokinase

VIII

Adenyl Kinase

IXa

Phosphorylase kinase (liver)

IXb

Phosphorylase (liver and muscle)

X

Cyclic AMP–dependent kinase

XI (Fanconi-Bickel)

Glucose Transporter 2

0

Glycogen Synthase

300 mg/dL

Ketones is recommended when plasma glucose reach what level?

1:1

normal ratio of B- hydroxybutyric acid to acetoacetic acid

defect in the metabolism of carbohydrate

An increase in serum acetone is indicative of what?

freshly collected urine (important in individuals with type 1 DM)

Specimen for ketone

Gerdhart’s ferric chloride test

Reacts only with acetoacetate

Nitroprusside test

10x more sensitive to acetoacetate

Acetest tablets

Detects acetoacetate and acetone (lesser degree)

Ketostix

Detects acetoacetic acid better than acetone

Ketosie assay

Detect B-hydroxybutyrate – not widely used

Lipids

commonly referred to as fats and composed mostly of carbon –hydrogen bonds. They are insoluble in blood and water but soluble in organic solvents

Lipoproteins

special transport mechanism of lipids for circulation in the blood

atherosclerosis

common disorder that occurs when fat, cholesterol and other substances build up in the walls of arteries and form hard structures called plaques. It is a pathogenic process that is the underlying cause of the common cardiovascular disorders of 

1. Myocardial infarction 

2. Cerebrovascular disease 

3. Peripheral vascular disease

MAJOR LIPIDS IN PLASMA

Arrange according to abundance

• Phospholipids

• Cholesterol

• Triglycerides

• Fatty acid

• Fat soluble vitamins (ADEK)

PHOSPHOLIPIDS

• also known as conjugated lipids

• It is the most abundant lipid derived from phosphatidic acid

liver and intestine

Where did phospholipids originate?

the conjugation of two fatty acid and a phosphorylated glycerol

Phospholipids are produce from?

150 -380 mg/dL

Reference Value of Phospholipids

FORMS OF PHOSPHOLIPID

• Lecithin / Posphatidylcholine – 70% 

• Sphingomyelin – 20%

• Cephaline – 10%

  • Phosphatidyl ethanolamine

  • Phosphatridyl serine

  • Lysolecithin + Inositol phosphatide

Sphingomyelin

the only phospholipid  in the membrane that is not derived from glycerol but from an amino alcohol called sphingosine

It is essential component of cell membrane (RBC and nerve sheet)

Nieman-Pick Disease (lipid storage disorder)

Sphingomyelin accumulates in the liver and spleen of patients suffering from?

3-hydroxy-5,6-cholestene

Cholesterol is also known as?

Cholesterol

unsaturated steroid alcohol containing four rings with single C-H side chain tail similar tor fatty acid

5 years

Cholesterol is measured in all adults starting age 20 years at least once in every?

< 200 mg/dL (desirable level)

Reference value of Cholesterol

200-239

Borderline for cholesterol

> 240 mg/dL

High cholesterol

0.026

conversion factor for cholesterol from mg/dL to mmol/L

Major Steroids

progestins, glucocorticoids, mineralocorticoids, androgens and estrogens

7-dehydrocholesterol

A small amount of cholesterol after first being converted to _________________, can also be transformed to vitamin D3 in the skin irradiation from sunlight

Cholesterol Ester (CE) – 70%

• NATURAL LIPID

• It is the cholesterol bound to fatty acid (hydrophobic form)

• It is the inactive form of cholesterol with protective properties and stored in cells

microsomal enzyme acyl–CoA cholesterol acyltransferase (ACAT)

Excess cholesterol is re-esterified by?

Lecithin –cholesterol Acyl tranferase (LCAT)

• It catalyzes the esterification of cholesterol (HDL) by promoting the transfer of fatty acids from lecithin to cholesterol which results in the formation of lysolecithin and cholesterol ester

• It enables HDL to accumulate cholesterol ester

Apo-1

Activator of LCAT

Unesterified free Cholesterol – 30%

• It is the active form of cholesterol with cytotoxic property

  • It is produced via lysosomal hydrolysis and becomes available for membrane, hormone  and bile acid synthesis

Cholesterol Esterification

The process of esterification is a “detoxification” step to reduce the accumulation of free cholesterol  through the action of acyltranferase enzymes

2mg/dL /year between 45-65 years old

Serum Total Cholesterol increases in what level?

Petroleum ether

What is added to the step methods to extract unesterified cholesterol and the same will be measured by Lieberman-Burchardt reagent?

Cholestadienyl Monosulfonic acid  (green end color)

Lieberman – Burchardt reaction end product

Cholesdienyl Disulfonic acid ( red end color)

Salkowski Reaction end product

One-step Method

1. Colorimetry

2. Pearson, Stern, and Mac Gavack

Two-step Method

1. Extraction, Colorimetry

2. Bloors

Three-step Method

1. Saponification, Extraction, Colorimetry

2. Abell – Kendal

Fourth-step Method

1. recipitation, Saponification, Extraction, Colorimetry

2. (PiSEC)Schoenheimer Sperry1.Parekh and jung

Lierberman- Burchardt

colorimetry reagent

Petroleum ether

saponification/extraction reagent

Alcoholic potassium hydroxide

saponification reagent

Digitonin

precipitation reagent

• Glacial acetic acid

• Acetic anhydride 

• Concentrated H2SO4

COLOR DEVELOPER  MIXTURE

(Liebermann –Burchardt reagent)

ENZYMATIC METHOD

• measure total cholesterol in serum and plasma

• Chromogen /colorimetric reagent: Phenol + 4-aminoantipyrine

Cholesteryl Ester Hydrolase

Cholesterol Esters -> free cholesterol + fatty acids

Cholesterol Oxidase

• Reacts with free cholesterol only

• Routine method

  • Most common method

Low Total Cholesterol

Elevated levels of ascorbic acid leads to?

5mg/dL

Bilirubin exceeding __________ decreases total cholesterol by 5% to 15%

ABELL, LEVY AND BRODIE METHOD

Formerly Reference method for cholesterol

Hexane; green

Extraction: it uses _______ instead  of petroleum ether

Colorimetry: Liebermann –Burchardt reagent

End color?

ISOTOPE DILUTION MASS SPECTROMETRY

the highest order method for serum cholesterol developed

It is the GOLD STANDARD method for cholesterol

Gas chromatography-IDMS

new reference method for cholesterol

INCREASE CHOLESTEROL  LEVELS

1. Hyperlipoproteinemia types II, III, V

2. Biliary cirrhosis

3. Nephrotic syndrome

4. Poorly controlled Diabetes mellitus

5. Alcoholism 

6. Primary hypothyroidism