Which one of the following is not a recognized feature of methaemoglobinaemia?
Correct Answer D:
Normal pO2 but decreased oxygen saturation is characteristic of methaemoglobinaemia.
Methaemoglobinaemia:
Methaemoglobinaemia describes haemoglobin which has been oxidized from Fe2+ to Fe3+. This is normally regulated by NADH methaemoglobin reductase, which transfers electrons from NADH to methaemoglobin resulting in the reduction of methaemoglobin to haemoglobin. There is tissue hypoxia as Fe3+ cannot bind oxygen, and hence the oxidation dissociation curve is moved to the left.
Congenital causes:
Acquired causes:
Features: '
Management:
A study is designed to compare the calcium levels of males and females who developed inflammatory bowel disease in childhood.
Which one of the following statistical tests is it most appropriate to use?
As the data is parametric and compares two independent sample from the same population an unpaired t-test is the most appropriate test to use.
Significance tests: types:
The type of significance test used depends on whether the data is parametric (something which can be measured, usually normally distributed) or non-parametric.
Parametric tests:
Non-parametric tests:
Paired data refers to data obtained from a single group of patients, e.g. Measurement before and after an intervention. Unpaired data comes from two different groups of patients, e.g. Comparing response to different interventions in two groups.
Which one of the following is not a recognized cause of hypocalcaemia?
Correct Answer B:
Hypocalcaemia: causes and management:
The clinical history combined with parathyroid hormone levels will reveal the cause of hypocalcaemia in the majority of cases.
Causes:
A 47-year-old man is seen in the respiratory clinic. He has been referred due to progressive shortness of breath. A CT scan showed emphysematous changes in the lungs. As he has never smoked alpha 1-antitrypsin levels were ordered and reported to be 10% of normal.
What is the most likely genotype of this patient?
Correct Answer A:
Alpha-1 antitrypsin deficiency:
Alpha-1 antitrypsin (A1AT) deficiency is a common inherited condition caused by a lack of a protease inhibitor (Pi) normally produced by the liver. The role of A1AT is to protect cells from enzymes such as neutrophil elastase.
Genetics:
Features:
Investigations:
*Trusted sources are split on which is a more accurate description.
The nitric oxide receptor is an example of a:
Correct Answer C:
The nitric oxide receptor is a soluble, intracellular guanylate cyclase.
Nitric oxide:
Previously known as endothelium derived relaxation factor, nitric oxide (NO) has emerged as a molecule which is integral to many physiological and pathological processes. It is formed from L arginine and oxygen by nitric oxide synthetase (NOS). An inducible form of NOS has been shown to be present in macrophages. Nitric oxide has a very short half-life (seconds), being inactivated by oxygen free radicals.
Effects:
Clinical relevance:
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