Biology of Disease

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CASE STUDY 14.1

Jim, a 52- year-old man, has suffered from angina over the

past 18 months. He has also been suffering from lethargy,

constipation and loss of concentration. His serum speci-

men was analyzed and yielded the following results (refer-

ence ranges are given in parentheses).

TSH >100 mU dm–3 (0.35 – 4.1 mU dm–3)

Cholesterol 12.8 mmol dm–3(<5.2 mmol dm–3)

Triacylglycerols 1.4 mmol dm–3(0.5 – 0.9 mmol dm–3)

Question

Explain these results.

CASE STUDY 14.2

Ted is a 60-year-old accountant with a past history of

myocardial infarction. He was admitted to the hospital

about 3 h after developing acute chest pain, fainting with

a heavy fall. The results for his ECG were equivocal. His

serum enzymes were measured on admission and after

24 and 48 h and give the following activities:

Enzyme admission 24 h 48 h reference range

CK 1160 570 190 <90 U dm–3

AST 90 45 25 <37 U dm–3

Question

Has Ted suffered a myocardial infarction?

CASE STUDY 14.3

Roger, a 37-year-old bank manager, has corneal arcus and

xanthomata. He had normal blood pressure and weight

and is a nonsmoker. However, he had family history of

myocardial infarction, as his father died following one at

the age of 40. A blood specimen was taken and analyzed

for its lipid content (reference ranges are given in paren-

theses).

Cholesterol 16.8 mmol dm–3 (<5.2 mmol dm–3)

Triacylglycerols 2.1 mmol dm–3 (0.4–1.8 mmol dm–3)

LDL Cholesterol 14.2 mmol dm–3 (<3.6 mmol dm–3)

HDL Cholesterol 1.3 mmol dm–3 (>1.2 mmol dm–3)

Questions

(a) How do you account for this abnormal lipid profile?

(b) How should Roger be treated?

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14.18 Summary

The cardiovascular system comprises the heart and the blood vessels that

supply the organs and tissues of the body with, for example oxygen and

nutrients, and remove CO 2 and other wastes. The heart pumps blood through

the pulmonary circulation that oxygenates the blood, and the systemic

circulation around the rest of the body. The heart pumps nonstop for millions

of beats during a person’s lifetime. However, there are a number of conditions

that can cause serious clinical problems. These can be investigated by listening

to the heart sounds using a stethoscope, by measuring its electrical activities

by an ECG, as well as studying its function by echocardiography. The rhythm

of the heart beat may be faulty and this may require correction, including the

insertion of an artificial pacemaker. The valves may function inappropriately

due to calcification or other diseases and may need to be replaced. Clinical

problems are also associated with blood vessels. These may become partially

or completely blocked because of atherosclerosis. When this happens to the

coronary arteries, bypass surgery with a grafted blood vessel may be required.

Atherosclerosis, caused by high levels of cholesterol in the blood, leads to