DMF Week 6 SAQ

1

Which of the following statements concerning acute inflammatory exudates is not correct?


  An exudate, by definition, has a high specific gravity (> 1.020) due to its high protein content.

  A suppurative exudate would be expected to have a high neutrophil content.

  The clear fluid inside a blister caused by a burn is an example of a serous exudate.

  A fibrinous exudate would be expected to contain a large number of fibroblasts.

  A purulent exudate would be expected to have a high neutrophil content.

2

Which of the following statements concerning epithelioid macrophages is not correct?


  A collection of epithelioid macrophages is known as a granuloma.

  Epithelioid macrophages collect around foreign bodies.

  Langhans giant cells form by the fusion of epithelioid macrophages.

  Epithelioid macrophages are so-named because, like epithelial cells, they tend to line surfaces

  Circulating monocytes recruited into the tissues can be transformed into epithelioid macrophages by cytokines released from T cells.

3

Which one or more of the following statements about viruses is correct?

A: Viruses have an envelope which protects their nucleic acid from degradation.

B: The presence of a viral envelope makes the virus less suscepticle to disinfectants

C: The presence of a viral envelope makes the virus less susceptible to antibody and complement lysis

D: Viruses must bind to one or more specific receptors on the host cell in order to invade the cell, and this process can be blocked by specific antibodies.

E: Binding of the virus to its specific host cell receptor invariably leads to viral uptake by endocytosis.


  If A, B, and C, are correct.

  If A and C are correct.

  If B and D are correct.

  If D is correct

  If all are correct

4

Which one of the statements regarding measures to provide active or passive immunity of short term (2 – 3 months duration) or long term (many years duration) against infectious diseases is correct?


  Administration of antibodies derived from the blood of donors will provide long term protection against several common pathogens

  Administration of T cells derived from the blood of donors will provide long term protection against several common pathogens

  Administration of vaccines composed of live attenuated pathogens is often efficient in inducing long term protection

  Immunity induced by live attenuated vaccines induces immediate protection from infection

  Protein adhesion molecules do not generate an effective immune response

5

The Hib vaccine is a conjugated vaccine provided for use in young children whose use has resulted in a remarkable decline in childhood infection due to Haemophilus influenzae. Which one of the following statements regarding this vaccine is correct?


  Use of the vaccine has resulted in a significant decrease in influenza infection in childhood

  A conjugated vaccine is one in which multiple antigens associated with the target organism are linked together to provide an effective response

  Since this vaccine is a component vaccine, regular boosters are required throughout life.

  The Hib vaccine predominantly induces the production of IgA antibodies directed against bacterial adhesins

  A conjugated vaccine provides T cell help for polysaccharide specific B cells

6

Baby S.T. is three days old and is in the neonatal unit, having been born at 32 weeks gestation after a prolonged labour. She weighs 2.1kg. She has become irritable, is feeding poorly and has become hypoxic. A paediatrician collects blood and CSF for culture.

The organism grown from blood cultures is a Gram positive coccus, which grows on Horse Blood agar as a small beta-haemolytic colony.

On the basis of the above results, which one of the organisms listed below is a likely cause of this baby’s illness?


  Streptococcus agalactiae

  Listeria monocytogenes

  Streptococcus pneumoniae

  E. coli

  Neisseria meningitidis

7

A seven year old boy presents with symptoms suggestive of meningitis, and a lumbar puncture is performed. The Gram stain shows the presence of large numbers of Gram negative diplococci. Which one of the organisms below is the likely cause of the patient's condition?


  Neisseria meningitidis

  Streptococcus pneumoniae

  Haemophilus influenzae

  E. coli

  Listeria monocytogenes