Biology of Disease

also affects several neurotransmitter systems in the brain including

dopamine, GABA, glutamate, serotonin, adenosine, noradrenaline

and opioid peptides. Many drugs are metabolized, in part, by the

P-450 system and consequently there may be competition between

ethanol and other drugs, such as barbiturates, whose hydroxylation

at the smooth endoplasmic reticulum is inhibited. This increases and

prolongs their action.

6. Many cosmetics obtained outside the UK contain lead and this is
   true for surma. Children using such cosmetics often develop lead
   poisoning. Investigations should include determining the levels of lead
   in whole blood and precursors of heme in erythrocytes.


7. Removal from the mercury source is important and will ensure the
   patient’s recovery. A chelating agent such as dimercaprol may be used
   to rapidly reduce mercury in the body.

CHAPTER 13

1. (a) T

(b) F

(c) T

(d) F

(e) F

2. 
   

   (A) Granulocyte; (B) basophil

   
   


3. 
   

   A has both HbS and HbC but no HbA; B is homozygous for HbS; and D
   is an HbC heterozygote. Note the Glu to Val (HbS) means a change of
   charge from – to 0, and the Glu to Lys (HbC), a change from – to +.

   
   


4. 
   

   Fetal Hb carries oxygen perfectly well but with a somewhat higher
   affinity than HbA.

   
   


5. 
   

Index iron deficiency anemia pernicious anemia

PCV D NA or D

MCV D I

MCH D NA or D

MCHC D NA or D

6. The production of erythrocyte cell precursors has been stimulated by
   Elsa’s severe anemia. As a result, the bone marrow spaces expanded
   in all areas of the skeleton leading to the deformities. It is these within
   the spine that caused compression of the spinal cord itself and the
   pain. Local irradiation may bring immediate relief. In addition, blood
   transfusions must be given to keep the Hb at near normal levels.


7. When the lining of a blood vessel is damaged, collagen fibers are
   exposed and circulating platelets stick to them. This causes them to
   degranulate releasing serotonin and ADP and other active biological
   molecules. Serotonin causes blood vessels to constrict restricting
   blood flow until clotting takes place. Clumping of platelets is triggered
   by ADP and the clump prevents further blood loss. The blood clotting
   cascade is then initiated.


8. Simon has hemophilia A. The manifestations encountered are caused
   by bleeding into soft tissues, such as muscle or into the peritoneal

CHAPTER 13

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