Course Assessment – Autumn 2007

Short Answer Questions.

Answer all questions.

Time allowed 1 hour.

A maximum of 10 marks will be awarded for each question

1. The transmittance of a solution of NADH at 340nm is 45%.  What is the absorbance of a 1 in 10 dilution of this solution?
2. List  the porphyrias that may present with acute attacks.
3. Name the enzyme that catalyses the rate limiting step of haem          synthesis and the product.
4. A radioisotope has a half life of 20 days.  What percentage of the initial activity is remaining after 10 days and 7 weeks?
5. A Family Doctor telephones for advice about results on a 24 year          old woman with anorexia nervosa. Serum results were:-

• • Sodium          141 mmol/L
  • Potassium     4.3 mmol/L
  • Urea       4.0 mmol/L
  • Creatinine          78 umol/L
  • Urate            37 umol/L  (149-446)
  • Bilirubin        2 umol/L
  • ALP                      73 IU/L (38-126)
  • ALT                 66 IU/L (<56)
  • Iron          6 umol/L
  • Transferrin      4.0 g/L
  • Transferrin saturation   6%
  • TSH                                      2.5 mU/L (0.5 – 4.2)
  • FT4          9.3 pmol/L  (10.8-19.3)
  • FT3          3.1 pmol/L  (3.5 -6.5)

What would you tell him?

1. A diabetic with a 24 hour creatinine clearance of 25mL/min and a serum creatinine of 180 umol/L was found to have an albumin excretion of 25 ug/min.  If the 24 hour urine has a volume of 2000 mL calculate the albumin/creatinine ratio in mg/mmol.
2. An endomysial antibody assay has been reported to have a diagnostic sensitivity of 88% and a diagnostic specificity of 97% for coeliac disease.  What is the probability that a positive result truly indicates coeliac disease in a group of subjects whose pre-test probability of coeliac disease is 1 in 1500?
3. List 5 ways in which Sickle cell disease may present clinically in       adults.
4. What is the pH of a 0.1 M aqueous solution of an acid of pKa = 4.756 in water at 25^oC?  State any assumptions you make.
5. A Family Doctor telephones you to ask advice about a 53 year old woman with hypertension, truncal obesity and abdominal striae.   What diagnosis is most likely and what first line test(s) would you suggest to investigate this potential diagnosis?
6. Calculate the approximate osmolality of an iv solution of dextrose saline containing 3% w/v glucose and 0.5% w/v sodium chloride

This post is tagged 2007, exams, Short Answers