CC Carbohydrate

CARBOHYDRATES

These are hydrates of aldehyde or ketone derivatives based on the location of the CO functional group.

monosaccharides, disaccharides, oligosaccharides, polysaccharides

Carbohyrdrates example

Glycol aldehyde

simplest carbohydrate (CHO).

Glucose

the only carbohydrate to be directly used for energy

Glycogen

glucose is stored as ______

muscle

Glucose does not accumulate in the ______

2/3

The brain is completely dependent on blood glucose for energy production –____ of glucose utilization in resting adults occurs in the central nervous system (CNS).

pyruvic acid, lactic acid and acetyl coenzyme A

Glucose metabolism generates ________ as intermediate products.

carbon dioxide, water and adenosine triphosphate

The complete oxidation of glucose yields

Sucrose

most common nonreducing sugar

ketone or aldehyde

Nonreducing sugar do not contain an active _______ group

PANCREAS

It is both an endocrine and exocrine organ in the control of carbohydrate metabolism.

insulin, glucagon and somatostatin

PANCREAS is an endocrine gland, it secretes the hormones’ _______ from different cells residing in the islets of Langerhans in the pancreas.

amylase

PANCREAS is an exocrine gland; it produces and secretes an ______ responsible for the breakdown of ingested complex carbohydrates.

Insulin

It is the primary hormone responsible for the entry of glucose into the cell.

It is normally released when glucose levels are high.

It is the only hormone that decreases glucose levels – hypoglycemic agent

It is stored from sources such as liver, fat and muscle.

It has a reciprocal relationship with glucagon.

It enhances membrane permeability to cells in the liver, muscle, and adipose tissue.

Serum measurements may be falsely low in the presence of hemolysis. An insulin-degrading enzyme found in red blood cells as well as in other tissues is responsible for this problem.

B-cells of islets of Langerhans

Insulin is synthesized by the ___________ in the pancreas

glycogenesis, lipogenesis and glycolysis

Insulin promotes

Glucagon

It is the primary hormone responsible for increasing glucose – hyperglycemic agent.

It enhances catabolic functions during fasting periods; promotes glycogenolysis

α-cells of the islets of Langerhans

Glucagon is synthesized by the _______ in the pancreas.

stress and fasting states

Glucagon is released during

25-50 pg/mL

Fasting plasma glucagon concentrations is normally

Cortisol and corticosteroids (Glucocorticoids)

These are secreted by the cells of the zona fasciculata and zona reticularis of the adrenal cortex.

They decreased intestinal entry of glucose into the cell.

They promote gluconeogenesis and lipolysis.

Catecholamines

These are released from the chromaffin cells of the adrenal medulla

They inhibit insulin secretion and promotes glycogenolysis and lipolysis.

Growth hormone (Somatotrophic)

It is secreted by the anterior pituitary gland.

It decreases entry of glucose into the cell.

It promotes glycogenolysis and glycolysis.

Thyroid hormones

It promotes glycogenolysis, gluconeogenesis and intestinal absorption of glucose.

Adrenocorticotrophic hormone (ACTH)

It stimulates release of cortisol from the adrenal cortex.

It promotes glycogenolysis and gluconeogenesis.

Somatostatin

It is also synthesized in the paraventricular and arcuate nuclei of the hypothalamus (a neuroendocrine hormone).

It primarily inhibits the action of insulin, growth hormone and glucagon.

delta cells of the islets of Langerhans

Somatostatin is produced by the _______ of the pancreas.

Hyperglycemia

It is an increase in blood glucose concentration.

It is toxic to beta cell function and impairs insulin secretion.

Causes: stress, severe infection, dehydration or pregnancy, pancreatectomy, hemochromatosis, insulin deficiency or abnormal insulin receptor.

≥ 126 mg/dl

Hyperglycemia FBS level

Hypoglycemia

It results from an imbalance between glucose utilization and production.

It involves decreased glucose levels and can have many causes.

The warning signs and symptoms are related to central nervous system.

Whipple’s triad

A diagnosis of hypoglycemia should not be made unless a patient meets the criteria of _______ – low blood glucose concentration, typical symptoms and symptoms alleviated by glucose administration.

5-hour glucose tolerance test

Diagnostic test for Hypoglycemia

65mg/dL to 70mg/dL

glucagon and other glycemic hormones are released into the circulation

≤ 60mg/dL

strongly suggest hypoglycemia

50mg/dL to 55mg/dL

observable symptoms of hypoglycemia appear

Diabetes Mellitus

It is a group of metabolic disorders characterized by hyperglycemia resulting from defects in insulin secretion, insulin receptors or both.

≥ 126 mg/dL

Fasting plasma glucose concentrations _____ on more than one testing are diagnostic of DM.

180 mg/dL (9.99 mmol/L)

Glucosuria occurs when the plasma glucose level exceeds ________ with normal renal function.

6:1

• In severe DM, the ratio of B-hydroxybutyrate to acetoacetate is _____

insulin

The entire process of ketosis can be reversed by ____ administration.

Insulin Dependent Diabetes Mellitus (IDDM)
Juvenile Onset Diabetes Mellitus Brittle Diabetes
Ketosis-Prone Diabetes

TYPE 1 DIABETES MELLITUS is Formerly known as

TYPE 1 DIABETES MELLITUS

It is a result of cellular-mediated autoimmune destruction of the B-cells of the pancreas.

Diabetic individuals have insulinopenia (absolute insulin deficiency) due to loss of pancreatic B-cells, and depend on insulin to sustain life and prevent ketosis.

Signs and symptoms: polyuria, polydipsia, polyphagia, rapid weight loss, hyperventilation, mental confusion and possible loss of consciousness.

Complications: microvascular disorders – nephropathy, neuropathy and retinopathy

80-90%

______ reduction in the volume of the B-cell is required to induce symptomatic type 1 DM – it is only after most of the beta cells are destroyed that hyperglycemia develops.

6

There is genetic association between type 1 DM and HLA DR3 and DR4 – the major locus is the major histocompatibility complex on chromosome number _.

IAA, GAD65

____ are more common in young children who develop type 1 diabetes, whereas _____ is more common in adults.

Idiopathic Type 1 DM

It is a form of type 1 diabetes that has no known etiology; it is strongly inherited; it does not have B-cell autoantibodies and have episodic requirements for insulin replacement.

Non-Insulin Dependent Diabetes Mellitus

Adult Type/Maturity Onset Diabetes Mellitus

Stable Diabetes

Ketosis-Resistant Diabetes

Receptor-Deficient Diabetes Mellitus

TYPE 2 DIABETES MELLITUS

TYPE 2 DIABETES MELLITUS

It is characterized by hyperglycemia due to an individual’s resistance to insulin; there is relative insulin deficiency.

It is associated with strong genetic predisposition and not related to an autoimmune disease.

It has been described as a geneticist’s nightmare.

The individuals are at risk of developing macrovascular and microvascular complications.

Risk factors: obesity, family history, advanced age, hypertension, lack of exercise, GDM, impaired glucose metabolism

3

It is recommended that adults ages 45 and older be screened for diabetes every ___ years, but screening should be performed earlier and more frequently if the individual is at high risk.

GESTATIONAL DIABETES MELLITUS (GDM)

It is a disorder characterized by impaired ability to metabolize carbohydrate usually caused by a deficiency of insulin, metabolic or hormonal changes.

It occurs during pregnancy and disappears after delivery but, in some cases, returned years later.

It is a type of glucose intolerance with onset or first recognition during pregnancy (diabetic women who become pregnant are not included in this category).

24 and 28

GESTATIONAL DIABETES MELLITUS (GDM) Screening should be performed between _____ weeks of gestation.

2-hour OGTT, 75g

The screening and diagnosis of GDM is by the performance of a _____ using ___ glucose load.

6 to 12

After giving birth, women with GDM should be evaluated ____ weeks postpartum.

≥ 92 mg/dL

Revised Diagnostic Criteria for GDM:

FBS

≥ 180 mg/dL

Revised Diagnostic Criteria for GDM:

1-hour GTT

≥ 153 mg/dL

Revised Diagnostic Criteria for GDM:

2-hour OGTT

10

GDM converts to DM within ____ years in 30% - 40% of cases.

venous plasma glucose

The standard clinical specimen for glucose methodologies is _______.

Fasting glucose in whole blood is ___ lower than in serum or plasma.

7 mg/dL

Venous blood glucose is ____ lower than capillary blood due to tissue metabolism; capillary blood glucose is same with arterial blood glucose.

30

A serum specimen is appropriate for glucose analysis if serum is separated from the cells within __ minutes, but if serum is in contact with cells for longer than 30 minutes, a preservative such as sodium fluoride that inhibits glycolysis should be added.

60%

CSF glucose concentrations should be approximately ___ of the plasma concentrations.

Peritoneal

______ fluid glucose is same with plasma glucose.

2 mg/dL /decade

Plasma glucose levels increase with age – fasting, _____; postprandial, ______; glucose challenge, 8 – 13 mg/dL/decade.

4 mg/dL/decade

Plasma glucose levels increase with age – fasting, _____; postprandial, _______; glucose challenge, 8 – 13 mg/dL/decade.

8 – 13 mg/dL/decade

Plasma glucose levels increase with age – fasting, 2 mg/dL /decade; postprandial, 4 mg/dL/decade; glucose challenge, ______ .

7 mg/dL/hour

At room temperature (20-25˚C), glycolysis decreases glucose by _____ in normal uncentrifuged coagulated blood.

2 mg/dL/hour

At refrigerated temperature (4˚C), glucose is metabolized at the rate of about _______ .

90 minutes

In serum specimens without bacterial contamination or leukocytosis, results remain clinically acceptable even after a delay of up to ______ before separation of serum and cells.

Alkaline Copper Reduction Method

Principle: Reduction of cupric ions to cuprous ions forming cuprous oxide in hot alkaline solution by glucose.

Benedict’s Method (Modification of Folin-Wu)

It is used for the detection and quantitation of reducing substances in body fluids like blood and urine.

Citrate or tartrate

Benedict’s Method (Modification of Folin-Wu) stabilizing agent

Alkaline Ferric Reduction Method (Hagedorn Jensen)

It involves reduction of a yellow ferricyanide to a colorless ferrocyanide by glucose (Inverse Colorimetry)

ENZYMATIC METHODS

Acts on glucose but not on other sugars and not on other reducing substances.

Glucose Oxidase Method

It measures the B-D glucose.

It also measures CSF and urine glucose

Polarographic Glucose Oxidase

It measures rate of oxygen consumption which is proportional to glucose concentration.

Glucose oxidase in the reagent catalyzes the oxidation of glucose by oxygen under first order conditions, forming hydrogen peroxide.

The enzymatic conversion of glucose is quantitated by the consumption of oxygen on an oxygen-sensing electrode.

The hydrogen peroxide is prevented from re-forming oxygen by adding molybdate, iodide, catalase and ethanol.

Hexokinase Method

It is the most specific glucose method; reference method.

Plasma collected using heparin, EDTA, fluoride, oxalate or citrate may be used for this test.

Other samples: urine, CSF and serous fluids

increased

The presence of bleach in the glucose oxidase method can cause false _____ of glucose.

ascorbic acid or uric acid

Hexokinase method is not affected by the presence of

Glucose Dehydrogenase Method

In this method, glucose is reduced to produce a chromophore that is measured spectrophotometrically or an electrical current.

The amount of NADH generated is proportional to the glucose concentration.

It provides results in close agreement with hexokinase procedures.

Mutarotase is also added to shorten the time necessary to reach equilibrium.

NADH

Glucose Dehydrogenase Method

The amount of _____ generated is proportional to the glucose concentration.

Mutarotase

Glucose Dehydrogenase Method

_______ is also added to shorten the time necessary to reach equilibrium

Dextrostics (Cellular Strip)

It is important in establishing correct insulin amount for next dose.

It is effective in reducing the rate of development of diabetic complications

Whole blood capillary glucose values obtained with point-of-care devices are useful for the detection of hyperglycemia and hypoglycemia in individuals with diabetes, and help to monitor and direct therapy, but should not be used to diagnose diabetes or hypoglycemic disorders.

≥ 140 mg/dL

An individual with a capillary glucose of _____ (7.8 mmol/L), should be rescreened with a fasting plasma glucose, HbA1c, or OGTT using venous samples.

Interstitial Glucose Measuring Device

It is used for continuous monitoring of glucose levels in people with diabetes.

It utilizes electrochemical methods to automatically and frequently measure glucose levels in the interstitial fluid of dermis or subcutaneous fat tissue, and require repeated calibration to plasma or whole blood glucose levels.

The results of this test provide information about glucose patterns over hours to days.

This glucose “trend analysis” can reveal useful findings for modifying treatment, such as unsuspected nocturnal hypoglycemia or postprandial hyperglycemia.

This device used for glucose measurements is only supplemental – may supplement but cannot replace conventional home blood glucose monitoring.

Interstitial glucose is in slow (5 – 30 minute) equilibrium with capillary blood glucose and therefore is not equal to blood glucose, except in stable systems.

RBS (Random Blood Sugar)

It is requested during insulin shock and hyperglycemic ketonic coma.

FBS

It is a measure of overall glucose homeostasis.

Requirement: NPO (Non-Per Orem) at least 8 hours before the test.

2-Hour PPBS (2-Hour Post Prandial Blood Sugar)

measures how well the body metabolizes glucose.

GTT

It is the multiple blood sugar test.

It is used to determine how well the metabolizes glucose over a required period of time, same with 2-HPPBS.

It should be performed to diagnose gestational diabetes.

It is not generally recommended for routine clinical use in the diagnosis of diabetes.

Janney-Isaacson Method (Single Dose Method)

Oral Glucose Tolerance Test (OGTT)
most common

Intravenous Glucose Tolerance Test (IVGTT)

It is used for Dm patients with gastrointestinal disorders.

Fasting blood sample is also required.

Glucose load: 0.5 g of glucose/kg body weight (given within 3 minutes) administered intravenously

The second blood collection is after 5 minutes of IV glucose.

30 mins

30 – 60 mg/dL above fasting

1-hour

20 – 50 mg/dL above fasting

2-hour

5 – 25 mg/dL above fasting

3-hour

fasting level or below

8 to 14 hours

Fasting for OGTT

75 g

WHO standard glucose load for OGTT

1.75 of glucose/kg body weight

OGTT glucose load for children

Non-Diabetic (Prediabetes)