CARBOHYDRATES Flashcards
Hydrates of aldehyde or ketone derivatices based on the location of the CO functional group
Carbohydrates
Simplest Carbohydrate (CHO)
Glycol Adlehyde
Only carbohydrate to be directly used for energy or stored as glycogen
Glucose
The ___ is completely dependent on blood glucose for energy produce
2/3 of glucose utilization in adults occurs in CNS
Brain
Glucose metabolism generates ___ as intermediate products
Pyruvic Acid
Lactic Acid
Acetylcoenzyme A
Product of complete oxidation of glucose
CO2
H2O
ATP
Reducing substances/ sugars
Glucose
Maltose
Fructose
Lactose
Galactose
Most common nonreducing sugar
Sucrose
Nonreducing sugars do not contain what?
Active ketone or aldehyde group
Both an endocrine and exocrine organ in the control of carbohydrate metabolism
Pancreas
Why is pancreas an endocrine gland?
It secretes hormones:
Insulin
Glucagon
Somatostatin
Why is pancreas an exocrine gland?
It produces and secretes Amylase
breakdown of ingested complex carbohydrates
Primary hormone responsible for the entry of glucose
Insulin
Where is Insulin synthesized in the pancreas
Beta cells
Normally released whn glucose levels are high
Insulin
Only hormone that decreases glucose levels
also called as a Hypoglycemic agent
Insulin
Insulin Promotes what
Glycogenesis
Lipogenesis
Glycolysis
Glucose to Gylcogen
Glycogenesis
Glucose to Fatty Acid
Lipogenesis
Glucose to Pyruvate or Lactate to Energy
Glycolysis
Glycogen to Glucose
Glycogenolysis
Glucose-6-phosphate from non-carbohydrate sources
Gluconeogenesis
Fats to Energy
Lipolysis
Primary hormone responsible for increasing glucose
(Hyperglycemic agent)
Glucagon
What cell synthesizes Glucagon
Alpha cells of Islets of Langerhans in the Pancreas
Other hormones that tend to increase glucose concentration:
5
- Cortisol & Corticosteroids
- Catecholamines
- Growth Hormone
- Thyroid Hormone
- Adrenocorticotropic hormone (ACTH)
Produced by delta cells of the islets of Langerhans of the pancreas
Somatostatin
Somatostatin function
Primarily inhibits the action of insulin, growth hormone and glucagon
Increase in blood glucose concentration
Toxic to beta cell function and impairs insulin secretion
Hyperglycemia
FBS level of a Hyperglycemic patient
(> /= 126 mg/dL)
Laboratory findings in Hyperglycemia
- Inc glucose in plasma & urine
- Inc urine specific gravity
- Ketonuria & Ketonemia
- Dec blood & urine pH (Acidosis)
- Electrolyte imbalance (Dec Na, Inc K, Dec HCO3)
Which type of DM patients are more likely to produce ketones?
Type 1 Diabetes Mellitus patients
Results from an imbalance between glucose utilization & production
Decreased glucose levels
Hypoglycemia
- Low blood glucose concentration
- Typical symptoms
- Symptoms alleviated by glucose administration
Whipple’s triad
Group of metabolic disorders characterized by hyperglycemia resulting from defects in insulin secretion, insulin receptors, or both
Diabetes Mellitus
Fasting plasma glucose concentration result that are diagnostic of DM
Greater than or Equal to 126 mg/dL
(On more than one testing)
Fasting plasma glucose concentration result that are diagnostic of DM
Greater than or Equal to 126 mg/dL
(On more than one testing)
When plasma glucose levels exceeds 180 mg/dL with normal renal function
Glucosuria
Other name for Type 1 Diabetes Mellitus
- Insulin-Dependent Diabetes Mellitus (IDDM)
- Juvenile Onset Diabetes Mellitus
- Brittle Diabetes
- Ketosis-Prone Diabetes
Result of a cellular-mediated autoimmune destruction of the Beta cells of the pancreas
Type 1 DM
Type 1 Diabetic Individuals have ___ due to loss of pancreatic beta cells
Insulinopenia
Absolute Insulin Deficiency
Signs & Symptoms
T1DM
- Polyuria
- Polydipsia
- Polyphagia
Other name for Type Type 2 Diabetes Mellitus
- Non-Insulin Dependent Diabetes Mellitus
- Adult Type/ Maturity Onset Diabetes Mellitus
- Stable Diabetes
- Ketosis-Resistant Diabetes
- Receptor-Deficient Diabetes Mellitus
Due to an individual’s resistance to insulin
Insulin deficiency
Type 2 DM
Type 2 DM is associated with strong ___ predisposition & not related to an autoimmune disease
Genetic
Characterized by impaired ability to metabolize carbohydrate, usually caused by a deficiency of insulin, metabolic or hormonal changes
Gestational Diabetes Mellitus
Screening for Gestational DM should be performed between?
24 and 28 weeks of gestation
Revised Diagnostic Criteria for GDM?
1. FBS
2. 1-hour OGTT
3. 2-hour OGTT
- > /= 92 mg/dL
- > /= 180 mg/dL
- > /= 153 mg/dL
Infants born to diabetic mothers are at increased risk for
Respiratory distress syndrome
Hypocalcemia
Hyperbilirubinemia
Standard clinical specimen
Venous plasma glucose
Fasting glucose in whole blood is ___ than in serum or plasma
15% LOWER
At Room temp, glycolysis decreases glucose by ____ in normal uncentrifuged coagulated blood
7 mg/dL/hour
Reaction of Cupric Ions to Cuprous ions forming Cuprous oxide in hot alkaline solution by glucose
Alkaline Copper Reduction Method
End result: Phosphomolybdic Acid or Phosphomolybdenum Blue
Folin Wu Method
End Product:
Arsenomolybdic Acid or
Arsenomolybdenum Blue
Nelson Somogyi Method
End Product:
Cuprous-Neocuproine Complex
Yellow or Yellow-Orange
Neocuproine Method
Used for detection & quantification of reducing substances in body fluids
Stabilizing agent: Citrate/ Tartrate
Benedict’s Method
Modification of Folin Wu
Involves reduction of a yellow ferricyanide to colorless ferricyanide
Inverse Colorimetry
Hagedorn Jensen
Alkaline Ferric Reduction Method
Uses Glacial HAC
End: Glycosylamine + Schiff’s Base
Dubowski Method
Ortho-toluidine
Measures the B-D glucose
Also meausres CSF & Urine glucose
Enzymatic Method
Glucose Oxidase Method
Uses enzymes:
Glucose Oxidase & Peroxidase
H2O2 is measured
Saifer Gernstenfield Method
Colorimetric Glucose Oxidase Method
Uses enzymes:
Glucose Oxidase & Peroxidase
H2O2 is measured
Saifer Gernstenfield Method
Colorimetric Glucose Oxidase Method
Measures the rate of Oxygen Consumption which is PROPORTIONAL to Glucose Concentration
Polarographic Glucose Oxidase
What enzymes are used in Polarographic Glucose Oxidase?
- Glucose Oxidase
- Catalase
- Molybdate
Most specific glucose method, also the reference method
Hexokinase Method
Enzymes used in Hexokinase Method
- Hexokinase
- Glucose-6-phoshate dehydrogenase
Not affected by presence of ascorbic acid or uric acid
Hexokinase method
Glucose is reduced to produce a chromophore that is measured spectrophotometrically
Glucose Dehydrogenase Method
Amount of NADH generated is ___ to the glucose concentration
proportional
Added to shorten the time necessary to reach equilibrium
Mutarotase
Glucose Testing in Urine
Clinitest tablets
Most commonly used method of OGTT
Janney-Isaacson Method
Single dose method
Most commonly used method of OGTT
Janney-Isaacson Method
Single dose method
Used for DM patients with gastrointestinal disorders
Intravenous Glucose Tolerance Test
Criteria for FPG
1. Non-Diabetic
2. Impaired PG
3. DM
- < 100 mg/dL
- 100-125 mg/dL
- > =126 mg/dL
Categories of OGTT
1. Normal
2. Impaired GTT
3. DM
- <140 mg/dL
- 140-199 mg/dL
- > =200 mg/dL
Diagnostic Criteria for Diabetes Mellitus
1. RBS
2. FBS
3. 2-HR
4. HbA1c
- > =200 mg/dL
- > = 126 mg/dL
- > =200 mg/dL
- > = 6.5%
Also known as Glycated Hemoglobin
Glycosylated Hemoglobin
HbA1c
What hemoglobin is irreversibly glycosylated at one or both N-terminal valines of the B-chains
Hemoglobin A
Significance of HbA1c
Reliable method in monitoring long-term glucose control
HbA1c reflects average blood glucose level over the previous ___
2-4 months
HbA1c is not suitable for patients with:
because they have low HbA1c
Shortened RBC lifespan
HbA1c is falsely increased in:
Older RBCs & Patients with IDA
For every 1% change in HbA1c value, ___ is added to plasma glucose
35 mg/dL
Normal HbA1c
< 5.7%
Increased risk HbA1c
5.7% - 6.4%
HbA1c
DM
(>= 6.5%)
Also known as Glycosylated or Glycated Albumin
Plasma Protein Ketoamine
Fructosamine
Fructosamine
reflection of short term glucose control (3-6 wks)
Fructosamine is used for monitoring diabetic individuals with:
Chronic Hemolytic Anmeia
Hemoglobin variants (Hb C or Hb S)
Decreased RBC lifespan
Congenital deficiency of one of 3 enzymes involved in galactose metabolism
Caused by failure to thrive syndrome in infants
Galactosemia
3 Enzymes involved in Galactosemia
- galactose-1-phoshphate uridyl transferase (GALT)
- galactokinase (GALK)
- uridine diphosphate galactose-4-epimerase (GALE)
Most common enzyme deficiency in Galactosemia
Galactose-1-phosphate uridyl transferase (GALT)
Autosomal recessive disorder characterized by Fructokinase deficiency
Essential Fructosuria
Fructokinase catalyzes conversion of?
Fructose to Fructose-1-phosphate
Defect of fructose 1,6-biphosphate aldolase B activity in liver, kidney and intestine
Inability to convert fructose-1-phosphate and fructose-1,6-biphosphate into dihydroxyacetone phosphate, glyceraldehydes
Hereditary Fructose Intolerance
Defect in Fructose-1,6-biphosphate results in failure of hepatic glucose generation of:
Gluconeogenic precursors such as:
Lactate & Glycerol
Inherited Autosomal Recessive trait
Inherited deficiencies of enzymes that control the synthesis or breakdown of glycogen
Glycogen Storage Disease
Most common GSD
Associated with Hyperlipidemia
Von Gierke
Type 1a
No Glucose-6-Phosphatase
Type 1B
G6P translocase
Type II
Pompe
1,4 Glucosidase
Type IIIa
Cori Forbes
De brancher
Liver & Muscle
Type IIIa
Cori Forbes
De brancher
Liver & Muscle
Type IIIb
De brancer
Liver
Type IIIb
De brancer
Liver
Type IV
Andersen
Brancher
Type V
McArdle
Muscle Phosphorylase
Type VI
Hers
Liver Phosphorylase
Type VII
Tarui
Phosphofructokinase
Type VIII
Adenyl kinase
Type IXa
Phosphorylase kinase
Type IXb
Phosphorylase
liver & muscle
Type X
Cyclic AMP-dependent kinase
Type XI
Fanconi-Bickel
Glucose transporter-2
40 to 60% of the blood plasma glucose level
CSF Glucose
Markedly decreased CSF glucose & increased WBC count
Bacterial Meningitis
Reference Value
Child
60-80 mg/dL
Reference Value
Adult
40-70 mg/dL
Formed during conversion of pro-insulin to insulin
Reliable indicators for pancreatic and insulin secretion
C-Peptide Test
Reference Value
C-peptide Test
0.90 - 4.3 ng/mL
Normal ratio of B-hydroxybutyrate & acetoacetic acid is
1:1
Ratio is greatly increased in
Diabetic Ketoacidosis
Reacts only with Acetoacetate
Gerhardt’s ferric chloride test
10x more sensitive to acetoacetate
Nitroprusside test
Detects acetoacetate & acetone in lesser degree
Acetest tablets
Detects acetoacetate better than acetone
Ketostix
Detects B-hydroxybutyrate
KetoSite assay