Disorders of lipid metabolism/Questions and case studies
Questions[edit | edit source]
- Which of the following statements regarding LDL is true?
- A – participates in the supply of triacylglycerols through peripheral tissue
- B – the main component of the surface part is cholesterol esters
- C – apolipoprotein C is needed for its function
- D – this particle is removed from the circulation by receptor-mediated endocytosis
- Which of the following is not involved in esterification in centripetal cholesterol transport?
- A – lecithin-cholesterol acyltransferase (LCAT)
- B – phosphatidylcholine
- C – apolipoprotein A
- D – apolipoprotein B
- Squalene is an intermediate metabolite in the biosynthesis of:
- A – cholesterol
- B – β-hydroxybutyrate
- C – unsaturated fatty acids
- D – sphingomyelin
- E – acylcarnitine
- The following does not apply to triacylglycerol hormone-sensitive lipase:
- A – catalyzes the breakdown of triacylglycerols, which are transported in the core of VLDL particles
- B – is induced by insulin
- C – is regulated by phosphorylation and dephosphorylation
- D – is an integral part of HDL
- What results from a complete lack of apolipoprotein B-48?
- A – VLDL cannot be formed
- B – chylomicrons cannot be formed
- C – LDL particles cannot be formed
- D – cholesterol synthesis in the liver is impaired
- Fatty acids released from adipose tissue are transported by circulation:
- A – bound to albumin
- B – as triacylglycerols carried by chylomicrons
- C – as lecithin on the surface of HDL particles
- D – by no specified mechanism
- Fatty acid catabolism stimulates gluconeogenesis in all of the following ways except:
- A – by contributing to the production of NADH
- B – by providing carbons for the glucose backbone
- C – by activating pyruvate carboxylase
- D – by contributing to the production of ATP
- Fatty acids serve as an energy source for (list all):
- A – liver
- B – brain
- C – musculature
- D – red blood cells
- Which statement about HDL is correct?
- A – has an antiatherogenic effect
- B – arise in adipose tissue
- C – carry triacylglycerols in their nucleus
- D – enable centripetal transport of cholesterol
- E – in the circulation they transmit apolipoprotein E and C to chylomicrons
- The proliferation of LDL particles is more dangerous from the point of view of atherogenicity than the proliferation of chylomicrons or VLDL because:
- A – LDL particles are smaller than VLDL or chylomicrons, so they penetrate the pores of the blood capillary wall and reach the target cells, to which they deliver cholesterol.
- B – contain lecithin-cholesterol acyltransferase, which esterifies cholesterol into non-polar cholesteryl esters.
- C – are taken up by target cells by endocytosis controlled by specific receptors
- D – their increased amount in circulation stimulates the endogenous formation of cholesterol in the endothelium of vascular capillaries
- Why are VLDL particles increased in alcoholics?
- Which lipoprotein particles are increased in the absence of lipoprotein lipase?
Case reports[edit | edit source]
Patient with hypertension and ischemic heart disease[edit | edit source]
A woman, 52 years old, with hypertension (controlled by medication), ischemic heart disease was examined for a lipid profile. The findings showed an increase in LDL-cholesterol (4.62 mmol/l), a decrease in HDL-cholesterol (0.90 mmol/l) and an increase in triacylglycerols (2.85 mmol/l). Her brother had mild hypercholesterolemia, but a significant decrease in HDL-cholesterol and normotriacylglycelemia, her sister had marked triacylglycerolemia.
- What are the main risk factors for coronary heart disease?
- What adverse effect can poorly treated diabetes have on lipoprotein metabolism?
- What does oxidized LDL-particles cause?
Patient after acute myocardial infarction[edit | edit source]
A 53-year-old man who suffered an acute myocardial infarction was followed by the attending physician. Triacylglycerol level: 1.6 mmol/l, HDL-cholesterol: 0.89 mmol/l, cholesterol: 9.5 mmol/l, calculated LDL-cholesterol also significantly increased. His younger brother had a family history of "high cholesterol".
- What is the most likely form of hyperlipoproteinemia in this patient?
- What is the mechanism of the therapeutic effect of cholestyramine (bile acid sequestrant) and statins?
A patient with hyperlipidemia[edit | edit source]
In a 65-year-old man, hyperlipidemia was discovered during a routine examination: cholesterol: 8.8 mmol/l, triacylglycerols: 2.4 mmol/l. The patient had periorbital edema , dry skin and hair, there was no family history of cardiovascular disease.
- What can be the causes of combined hyperlipoproteinemia?
- What other examinations do you recommend for differential diagnosis?
Note: the thyroid disorder must be treated primarily, hyperlipoproteinemia usually resolves.
Patient with xanthomas and hypercholesterolemia[edit | edit source]
A 55-year-old, obese woman came to the general practitioner with nodules about 2 cm in diameter on her forearm. She had yellowish streaks on her palms (palmar striae).
- cholesterol: 11,9 mmol/l
- triacylglycerides: 8.7 mmol/l
- ELFO of lipoproteins: broad β fraction
- What type of hyperlipoproteinemia is it?
A 46-year-old manager on a preventive check-up[edit | edit source]
His father had a history of acute myocardial infarction at the age of 57, but he lived to be 79 years old. The patient is obese (104 kg, 175 cm), blood pressure 170/100 mmHg.
- cholesterol: 6,5 mmol/l
- triacylglycerols: 2.9 mmol/l
- HDL cholesterol: 0.84 mmol/l
- What are the health risks for this patient?
Links[edit | edit source]
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Source[edit | edit source]
- MASOPUST, Jaroslav – PRŮŠA, Richard. Patobiochemie metabolických drah. 1. edition. 1999. 182 pp. pp. 80-85. ISBN 80-238-4589-6.