Test 138  (Pathology)

1. Regarding the genetics of tumour:

a. the retinoblastoma gene is an oncogene

b. embryos that are homozygous for mutate 
    retinoblastoma genes can not develop to term

c. retinoblastoma is associated with bone tumour

d. bilateral retinoblastoma is often caused by somatic 
    mutation

e. p53 gene prevents neoplasia
 

Answer
a.F   b.T   c.T   d.F   e.T
The retinoblastoma gene is an anti-oncogen or tumour suppressor gene. Bilateral retinoblastoma is often caused by germline mutation. p53 gene causes the tumour cells to undergo apoptosis.

2. Macrophages

a. are derived from blood monocytes

b. have a longer life span than neutrophils

c. can harbour viable organisms

d. involves in the delayed hypersensitivity response

e. produce cytokines

Answer
a.T   b.T   c.T   d.T  e.T
Mycobacteria tuberculosis bacilli can be ingested macrophages without being killed.
They can produce interleukins and tumour necrosis factors.

3. The following are true about multinucleate giant cells:

a. they are formed by the fusion of macrophages

b. they have increased phagocytic activity compared with macrophages

c. Langerhan's cells are seen in tuberculosis

d. foreign-body giant cells have nuclei scattered throughout the cytoplasm

e. Touton giant cells have clear cytoplasm

Answera.T  b.F  c.F  d.T  e.T
Multinucleate giant cells are formed by macrophages 
which attempt to engulf the same particle simultaneously leading to fusion of the membrane. They have no phagocytic action. Langhan's cells are seen in tuberculosis whereas Langerhan's cells are antigen presenting cells found in the epidermis.
The clear cytoplasm in Touton giant cells result from ingestion of lipid.
.

4. Factors predisposing to venous thrombosis include:

a. thryombocytopenia

b. polycythaemia

c. dehydration

d. thrombophlebitis

e. paraproteinaemia

Answer
a.F   b.T  c.T  d.T   e.T
All the above conditions with the exception of thrombocytopenia increases the blood viscosity and hence risk of venous thrombosis.

5. Oxygen-dependent killing mechanisms found in neutrophils include:

a. lactoferrin

b. myeloperoxidase

c. hydrogen peroxide

d. histamine

e. lysosomal proteolysis

 
Answer
a.F   b.T  c.T  d.F   e.F
Histamine is not found in the neutrophils. Both lysosomal proteolysis and lactoferrin are oxygen-independent mechanisms.

 

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