Chemistry SOLO 2

Clinical Chemistry SOLO 2

Glycolysis

metabolism of glucose molecule to pyruvate or lactate for production of energy

gluconeogenesis

formation of glucose-6-phosphate from noncarbohydrate sources

glycogenolysis

breakdown of glycogen to glucose for use as energy

glycogenesis

conversion of glucose to glycogen for storage

lipogenesis

conversion of carbohydrates to fatty acids

lipolysis

decomposition of fat

What hormone is A?

stomatostatin

What hormone is B?

glucagon

What hormone is D?

Insulin

What hormone is C?

Epinephrine

Type 1 diabetes

beta cell destruction leading to absolute insulin deficiency and development of autoantibodies

Type 2 diabetes

insulin resistance with an insulin secretory defect due to progressive loss of adequate beta cell insulin secretion (relative insulin deficiency)

other diabetes

• monogenic diabetes syndromes

• neonatal and maturity onset

• diseases of the exocrine pancreas

• drug or chemical induced

gestational diabetes

glucose intolerance during pregnancy diagnosed in the second or third trimester of pregnancy

lab findings of hyperglycemia

• decreased/absent insulin

• increased glucose in plasma/urine

• increased urine specific gravity

• increased serum and urine osmolality

• ketones in serum and urine

• decreased blood/urine pH

• electrolyte imbalance

HbA1c diabetes diagnostic criteria

>/= 6.5%

Fasting plasma glucose diabetes diagnostic criteria

>/= 126 mg/dL

2h/random plasma glucose diabetes diagnostic criteria

>/= 200 mg/dL

Oral glucose tolerance test normal

2h pg </= 140 mg/dL

Oral glucose tolerance test impaired

2h pg = 140-199 mg/dL

Oral glucose tolerance test diabetes

2h pg >/= 200 mg/dL

Level 1 hypoglycemia

• glucose alert value

• <70mg/dL

Level two hypoglycemia

• clinically significant hypoglycemia

• <54 mg/dL

Level 3 hypoglycemia

• severe hypoglycemia

• no specific glucose threshold

• associated with severe cognitive impairment

methods of glucose measurment

• glucose oxidase

• hexokinase

• clinitest

Methods of glycosylated hemoglobin measurement

• affinity chromatography

• cation-exchange chromatography

• latex immunoagglutination inhibition

• high performance liquid chromatography

• electrophoresis

Nondiabetic patient reference value for glucose, plasma or serum fasting

70-99 mg/dL

Nondiabetic patient reference value for HbA1c

4.0-5.6

Nondiabetic patient reference value for microalbumin in urine

<25 mg/g creatinine

autoantibody markers for type 1 diabetes

• islet cell cytoplasmic autoantibodies

• glutamic acid decarboxylase autoantibodies

• insulinoma-associated-2 autoantibodies

• insulin autoantibodies

• zinc transporter 8

Microvascular diabetes complications

• diabetic retinopathy

• diabetic nephropathy

• neuropathy

macrovascular diabetes complications

• cardiac

• cerebral

• peripheral large vessels

monosaccharides

• termed aldoses or ketoses

• glucose

• galactose

• fructose

disaccharides

• composed of two monosaccharides

• maltose

• lactose

• sucrose

polysaccharides

large numbers of monosaccharides linked together

Starch

• major carbohydrate storage in plants

• composed of amyloses and amylopectins that contain glucose residues

glycogen

• major carbohydrate storage in animal

• a heavily branched polysaccharide containing many glucose residues

• most abundant in the liver and skeletal muscle

insulin

• a protein produced and secreted by the beta cells of the islets of langerhans in the pancreas

• decreases blood glucose by stimulating the uptake of glucose into fat and muscle and stimulated glycolysis

• promotes conversion of glucose into glycogen or fat for storage

• inhibits glucose production by the liver

• stimulated protein synthesis and inhibits protien breakdown

glucagon

• protein hormone secreted by the alpha cells of the pancreas that increases blood glucose through glycogenolysis and gluconeogenesis in the liver

• increases lipolysis and enhances ketogenesis

• levels increased during stree and exercise and in hypoglycemic episodes

epineprhine

• catecholamine secreted by the adrenal gland that stimulates glucagon secretion and inhibits insulin secretion

• increased production in physical or emotional stress and in pheochromocytomas

growth hormone

• secreted by the anterior pituitary gland

• stimulates gluconeogenesis

• enhances lipolysis

• opposes insulin stimulated glucose uptake

cortisol

• “stress hormone”

• stimulates gluconeogenesis

thyroxine

• increases the rate of intestinal glucose absorption

• stimulates glycogenolysis and gluocneogenesis

somatostatin

inhibits secretion of insulin, glucagon, and growth hormone

ketones

produced when the body doesn’t have enough carbohydrates for clls to burn for energy and it burns fat instead

ketones examples

• acetone

• Beta-hydroxybutyrate

• acetoacetic acid

Normally long chain fattty acids are:

• taken up by the liver

• re-esterified to triglycerides

• stored in the liver or incorporated in VLDL

• returned to plasma

Ketone bodies may form due to:

• decreased availability of carbohydrates

• decreased use of carbohydrates

diabetic ketoacidosis

• complication from T1DM

• without enough insulin, the body can’t use sugar properly for energy

• this prompts the release of hormones that break down fat as fuel, which produces acidic ketones

• excess ketones build up in the blood and eventually “spill over” into the urine

hyperosmolar nonketotic coma

• characterized by hyperglycemia, extreme dehydration, hyperosmolar plasma, and altered conciousness

• complications: coma, seizures, death

• most often occur in T2DM in the setting of physiological stress, which increases hormones that favor elevated glucose hormones

• hyperglycemia → fluid shift from cells to blood→ increased urine output→ dehydration

Whipple’s triad

• symptoms are known or likely to be caused by hypoglycemia

• low glucose is measured when symptoms occur

• relief of symptoms occurs when glucose is increased to normal