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Old 08-12-2010
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Biochemistry Daibetic Ketoacidosis

A 45-year-old man with a history of poorly controlled diabetes mellitus is admitted to the intensive care unit because of severe hyperglycemia. The man has had increased thirst, urination throughout the morning, with episodes of nausea and vomiting and general weakness. He appears ill. His temperature is 37.2C (99.0F), pulse is 115/min, respirations are 25/min, and blood pressure is 138/68 mm Hg. Physical examination shows dry skin and dry mucous membranes and his breath smells like nail polish remover. Arterial blood gas studies show:
Arterial CO2: 29 mmHg
Arterial pH: 7.34
Arterial HCO3-: 15 mEq/L
Which of the following measurements is most likely to be decreased in this patient?
A. Plasma acetone
B. Plasma catecholamines
C. Plasma glucagon
D. Ratio of acetoacetate to β-hydroxybutyrate
E. Ratio of β-hydroxybutyrate to acetoacetate
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Old 08-12-2010
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D. Ratio of acetoacetate to β-hydroxybutyrate...
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Old 08-12-2010
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Show Teeth BioChem.. When will it Be oVer!

Quote:
Originally Posted by good_boy_1234 View Post
A 45-year-old man with a history of poorly controlled diabetes mellitus is admitted to the intensive care unit because of severe hyperglycemia. The man has had increased thirst, urination throughout the morning, with episodes of nausea and vomiting and general weakness. He appears ill. His temperature is 37.2C (99.0F), pulse is 115/min, respirations are 25/min, and blood pressure is 138/68 mm Hg. Physical examination shows dry skin and dry mucous membranes and his breath smells like nail polish remover. Arterial blood gas studies show:
Arterial CO2: 29 mmHg
Arterial pH: 7.34
Arterial HCO3-: 15 mEq/L
Which of the following measurements is most likely to be decreased in this patient?
A. Plasma acetone
B. Plasma catecholamines
C. Plasma glucagon
D. Ratio of acetoacetate to β-hydroxybutyrate
E. Ratio of β-hydroxybutyrate to acetoacetate

Answer-------> D.

The question above is asking you about Ketone Body Metabolism. Ketone Body formation is normal function within Hepatic tissue of the Human body. Approx 90 min following a meal the Liver will begin producing ketones. The levels are normally undetectable because Both the Muscle and Renal Cortex use them very quickly.

Ketone Metabolism Basics:

During Fasting conditions the liver will use Fatty Acids for Version:1.0 StartHTML:0000000105 EndHTML:0000005999 StartFragment:0000001435 EndFragment:0000005963 D.

The question above is asking you about Ketone Body Metabolism. Ketone Body formation is normal function within Hepatic tissue of the Human body. Approx 90 min following a meal the Liver will begin producing ketones. The levels are normally undetectable because Both the Muscle and Renal Cortex sequester them.

Ketone Metabolism Basics: (Under Normal Fasting Conditions)

The liver is sequestering Fatty Acids for Beta Oxidation to yield lots of Acetyl Coa. The Acetyl Coa is converted to HMG Coa by the Enzyme HmgCoA Synthase. Next HMG- CoA is converted to Acetoacetate (KETONE) by HMG-CoA Lyase. The Acetoacetate is both directly released into the blood and also converted by NADH to b-hydroxybutyrate (KETONE). Both Actoacetate and b-hydroxybutyrate are released into the blood in approx EQUAL quanities with Acetone as a Minor By product (nail polish smell).

I think of Acetoactate as the (ACTIVE) Ketone which can be readily picked up and utilized by tissues. Conversely b-hydroxybutyrate requires another conversion before tissues can use it, which may cause it to Persist in the blood LONGER than Acteoacetate and therefore I think of b-hydroxybutyrate as the (LESS ACTIVE) Ketone.
During Diabetic ketoacidosis there is huge amounts of both Acetoacetate and Β-hydroxybutyrate being released into the blood. Eventually the tissues will become saturated and there will be no more uptake of either of these metabolites. However there is a very distinct change in the ratio of Acetoacetate and b-hydroxybutyrate , in that more Acetoacetate(ACTIVE) is taken up by tissues than the b-hydroxybutyrate (LESS ACTIVE) because Acetoacetate does not need that extra conversion step… Therefore there will be more b-hydroxybutyrate than Acetoacetate in the blood.
There are quite a few details I left out, but I think this is the bare minimum of what you need to understand to answer this question. If anyone sees any gross errors please point them out.. GOOD LUCK

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Last edited by Jones_WILLY; 08-12-2010 at 12:04 PM. Reason: Double Paste
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