Carbohydrates Flashcards
The simplest carbohydrate
Glycol aldehyde
Most common nunreducing sugar
Sucrose
Pancreas
Exocrine:
Endocrine:
Enzymes (AMS, LPS)
Hormones (Insulin, glucagon, somatostatin)
Hyperglycemic Hormones “GAG CHET”
Glucagon
ACTH
GH
Cortisol
Human Placental Lactogen
Epinephrine
Thyroxine
Hyperglycemia (≥126 mg/dL)
Electrolyte Imbalance:
Increased:
Decreased:
Potassium
Sodium, Bicarbonate
Hypoglycemia
= Symptoms
= Diagnostic
50-55 mg/dL
≤50 mg/dL
Whipple’s triad (Hypoglycemia)
Low blood glucose concentration
Typical symptoms
Symptoms alleviated by glucose administration
Ratio of BHA to AA in severe DM (Normal = 1:1)
6:1
IDDM
Type 1 DM
Juvenile Onset
Type 1 DM
Brittle
Type 1 DM
Ketosis-prone
Type 1 DM
80-90% reduction of beta-cells
Symptomatic Type 1 DM
HLA-DR3 and DR4
Type 1 DM
(+) Glutamic acid decarboxylase (GAD65)
Type 1 DM
(+) Insulin autoantibodies
Type 1 DM
(+) Microalbuminuria: 50-200 mg/24 hours = Diabetic nephropathy
Type 1 DM
(-) C-peptide
Type 1 DM
Complications of Type I DM
Microvascular disorders:
Nephropathy Neuropathy Retinopathy
NIDDM
Type 2
Adult type/Maturity Onset
Type 2
Stable
Type 2
Ketosis-resistant
Type 2
Receptor-deficient
Type 2
Insulin resistance: relative insulin deficiency
Type 2
Strong genetic predisposition
Type 2
Geneticist’s nightmare
Type 2
If untreated > glucose: >500 mg/dL > nonketotic hyperosmolar coma
Type 2
Screening: 1hr GCT (50g) – bet. 24 and 28 weeks of gestation
Gestational DM
Confirmatory: 3-hr GTT (100g)
Gestational DM
Infants: at risk for respiratory distress syndrome, hypocalcemia, hyperbilirubinemia
Gestational DM
After giving birth, evaluate 6-12 weeks postpartum
Gestational DM
Converts to DM w/in 10 years in 30-40% of cases
Gestational DM
OGTT (GDM)
FBS =
1-Hr =
2-Hr =
3-Hr =
GDM =
≥95 mg/dL
≥ 180 mg/dL
≥ 155 mg/dL
≥ 140 mg/dL
2 plasma values of the above glucose levels are exceeded
Impaired fasting glucose (Pre-diabetes)
FBS =
Impaired glucose tolerance FBS =
100-125 mg/dL
<126 mg/dL 2-Hr OGTT = 140-199 mg/dL
FBS
WB = [?] ower than in serum or plasma
VB = [?] lower than capillary and arterial blood
15%
7 mg/dL
60-70% of the plasma glucose
CSF glucose
Same with plasma glucose
Peritoneal fluid glucose
Plasma glucose increases w/ age
Fasting:
Postprandial:
Glucose challenge:
2 mg/dL/decade
4 mg/dL/decade
8-13 mg/dL/decade
Separate serum/plasma from the cells
w/in 1 hour (Preferably w/in 30 mins)
Glycolysis at room temperature
5-7%/hr
Glycolysis at refrigerated temperature
1-2 mg%/hr
Cupric Cuprous Cuprous oxide
Copper reduction methods
Cuprous ions + phosphomolybdate phosphomolybdenum blue
Folin Wu
Cuprous ions + arsenomolybdate arsenomolybdenum blue
Nelson-Somogyi
Cuprous ions + neocuproine Cuprous-neocuproine complex (yellow)
Neocuproine method
Reducing substances in blood and urine
Benedict’s method
Ferricyanide —(Glucose)–> Ferrocyanide (Yellow) (Colorless)
Alkaline Ferric Reduction method (Hagedorn-Jensen)
Schiff’s base
Ortho-toluidine (Dubowski method)
Measures beta-D-glucose (65%)
Glucose oxidase
Converts alpha-D-glucose (35%) to beta-D-glucose (65%)
Mutarotase
Absorbance at 340nm
NADH/NADPH
Consumption of oxygen on an oxygen-sensing electrode
Polarographic glucose oxidase
GLUCOSE: Most specific method
Hexokinase method
GLUCOSE: Reference method
Hexokinase method
Uses G-6-PD
Hexokinase method
Most specific enzyme rgt for glucose testing
G-6-PD
Interfering substances (Glucose oxidase)
False-decreased
Bilirubin
Uric acid
Ascorbate
Major interfering substance in hexokinase method (false-decreased)
Hemolysis (>0.5 g/dL Hgb)
Cellular strip ; Strip w/ glucose oxidase, peroxidase and chromogen
Dextrostics
OGTT
(Single dose) = most common
(Double dose)
Drink the glucose load within
Janney-Isaacson method
Exton Rose
5 mins
For patients with gastrointestinal disorders (malabsorption)
IVGTT
Glucose: 0.5 g/kg body weight
IVGTT
Given w/in 3 mins
IVGTT
1st blood collection: after 5 mins of IV glucose
IVGTT
Ambulatory
OGTT
Fasting: 8-14 hours
OGTT
Unrestricted diet of 150g CHO/day for 3 days
OGTT
Do not smoke or drink alcohol
OGTT
Glucose load
= adult (WHO std)
= pregnant
= children
75 g
100 g
1.75 g glucose/kg BW
2-3 months
HbA1c
Glucose = beta-chain of
HbA1
= 35 mg/dL increase in plasma glucose
1% increase in HbA1c
HbA1c
= prolonged hyperglycemia
= cutoff
18-20%
7%
HbA1c Specimen:
EDTA whole blood
HbA1c Test:
Affinity chromatography (preferred)
High HbA1c
IDA and older RBCs
Low HbA1c
RBC lifespan disorders
2-3 weeks
Fructosamine (Glycosylated albumin/ plasma protein ketoamine)
Useful for patients w/ hemolytic anemias and Hgb variants
Fructosamine (Glycosylated albumin/ plasma protein ketoamine)
Not used in cases of low albumin
Fructosamine (Glycosylated albumin/ plasma protein ketoamine)
Fructosamine (Glycosylated albumin/ plasma protein ketoamine) Specimen:
Serum
Congenital deficiency of 1 of 3 enzymes in galactose metabolism
Galactosemia
Galactose-1-phosphate uridyl transferase (most common) Galactokinase
Uridine diphosphate galactose-4-epimerase
Galactosemia
Autosomal recessive
Essential fructosuria
Glycogen Storage Disease
Fructokinase deficiency
Essential fructosuria
Defective fructose-1,6-biphosphate aldolase B activity
Hereditary fructose intolerance
Failure of hepatic glucose generation by gluconeogenic precursors such as lactate and glycerol
Fructose-1,6-biphosphate deficiency
Defective glycogen metabolism
Glycogen Storage Disease
Glycogen Storage Disease Test:
IVGTT (Type I GSD)
Glucose-6-Phosphatase deficiency (most common worldwide)
Ia = Von Gierke
Alpha-1,4-glucosidase deficiency (most common in the Philippines)
II = Pompe
Debrancher enzyme deficiency
III = Cori Forbes
Brancher enzyme deficiency
IV = Andersen
Muscle phosphorylase deficiency
V = McArdle
Liver phosphorylase deficiency
VI = Hers
Phosphofructokinase deficiency
VII = Tarui
Glucose transporter 2 deficiency
XII = Fanconi-Bickel
CSF glucose: Collect blood glucose at least [?] before the lumbar puncture (Because of the lag in CSF glucose equilibrium time)
60 mins (to 2 hrs)
Normal CSF : serum glucose ratio
< 0.5
Formed during conversion of pro-insulin to insulin
C-peptide
Normal C-peptide : insulin ratio
5:1 to 15:1
Differentiate pancreatic insufficiency from malabsorption (low blood or urine xylose)
D-xylose absorption test
Acetoacetate
Gerhardt’s ferric chloride test
10x more sensitive to acetoacetate than to acetone
Nitroprusside test
Acetoacetate and acetone
Acetest tablets
Detects acetoacetate better than acetone
Ketostix
Detects beta-hydroxybutyrate but not widely used
KetoSite assay
RBS =
<140 mg/dL
FBS =
70-100 mg/dL
HbA1c =
3-6%
Fructosamine =
205-285 μmol/L
2-Hr PPBS =
<140 mg/dL
GTT:
30 mins =
1-Hr =
2-Hr =
3-Hr =
30-60 mg/dL above fasting
20-50 mg/dL above fasting
5-15 mg/dL above fasting
fasting level or below
O2 consumption α glucose concentration
Polarographic glucose oxidase