Chemical pathology

Question 1

Define the term “acute phase protein”.

Answer 1

A protein whose serum concentration is either increased or decreased as a result of
inflammation.

Question 2

. List five acute phase proteins. For each protein, state the direction of change occurring
during inflammation. (10 X ½ = 5 marks)

Answer 2

a. Any 5 of below:
i. Albumin decreased
ii. Transferrin decreased
iii. Complement increased
iv. C-reactive protein increased

Question 3

. List four mechanisms / hormones which enhance osteoclast activation in tumour-induced
hypercalcaemia

Answer 3

Elevated parathyroid hormone
c. Elevated parathyroid hormone related peptide
d. Syndecan production
e. Increased Alpha 1 hydroxylase activity (therefore increased activated vitamin D)
f. Increased glucocorticorticoids
g. IL-1 and IL-6
h. TNF alpha

Question 4

List two markers of bone resorption.

Answer 4

Collagen type 01 telopeptides
hydroxyproline
Pyridinium crosslinks
Acid phosphatase

Question 5

List two markers for bone formation.

Answer 5

BAP
alkaline phosphatase
Collagen type 01 propeptides
Osteocalcin

Question 6

State one mechanism for the hypercalcaemia associated with certain malignancies

Answer 6

PTHrP; RANKL; Vit D activation; etc.

Question 7

4. Name a biochemical marker of:
   a. Increased osteoblastic activity. (½ mark)
   b. Increased osteoclastic activity. (½ mark)

Answer 7

1. Serum alkaline phosphatase (ALP)
2. Urine deoxypyridinoline (DPD) cross-links

Question 8

25. Name two clinical symptoms for each of the following:
    a. Hypocalcaemia. (1 mark)
    b. Hypercalcaemia (1 mark)

Answer 8

1. Tetany, carpopedal spasm, stridor, convulsion
2. Abdominal pain, polyuria, kidney stones, mental confusion

Question 9

26. State two mechanisms whereby malignant tumours can give rise to hypercalcaemia. (2 marks)

Answer 9

1. Direct invasion of bone, liberating Ca and Pi from hydroxyapatite
2. Remotely, via secretion of PTH related peptide (PTHrP)

Question 10

Explain how oestrogen deficiency can give rise to osteoporosis.

Answer 10

Oestrogen induces osteoblasts to produce osteoprotegerin (OPG), a decoy receptor which prevents
RANK ligand on osteoblasts interacting with its receptor, RANK on osteoclasts. This prevents
bone resorption and osteoporosis in the long term.

Question 11

Explain the two mechanisms underlying the bone changes associated with chronic renal
failure.

Answer 11

High PiFGF23inhibits vit D activationdecreased CaPTHbone resorption
(5)
b. Chronic acidosis  bone demineralisation (1)