Mark Evans

Publications (2)5.33 Total impact

• Source

  Available from: Claire Turner

  Article: Breath acetone concentration decreases with blood glucose concentration in type I diabetes mellitus patients during hypoglycaemic clamps.

  Claire Turner, Christopher Walton, Shu Hoashi, Mark Evans
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  ABSTRACT: Conventional wisdom is that breath acetone may be markedly elevated in type 1 diabetes, but that this only occurs during poor blood glucose control and/or intercurrent illness. In contrast, little is known about breath acetone at more representative everyday blood glucose levels in diabetes. We used selected ion flow tube mass spectrometry to monitor the breath of eight patients with type 1 diabetes mellitus during 'insulin clamp' studies in which insulin and glucose were infused into patients to lower blood glucose levels in steps from normal values into the low glucose (hypoglycaemic) range. The concentration of acetone in breath and the blood sugar concentration of the patients were monitored at each blood glucose concentration. The blood glucose level at the start of the study was typically about 6 mM L(-1), whereas the breath acetone concentration at this blood glucose level was unexpectedly variable, ranging from 1 part-per-million to 21 ppm, in contrast to what was previously believed, i.e. that type 1 diabetes mellitus is characterized by high acetone levels. In all eight patients, the breath acetone declined linearly with blood glucose concentration.
  Journal of Breath Research 12/2009; 3(4):046004. · 2.54 Impact Factor
• Source

  Available from: Claire Turner

  Article: An exploratory comparative study of volatile compounds in exhaled breath and emitted by skin using selected ion flow tube mass spectrometry.

  Claire Turner, Bhavin Parekh, Christopher Walton, Patrik Spanel, David Smith, Mark Evans
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  ABSTRACT: Selected ion flow tube mass spectrometry (SIFT-MS) has been used to carry out a pilot parallel study on five volunteers to determine changes occurring in several trace compounds present in exhaled breath and emitted from skin into a collection bag surrounding part of the arm, before and after ingesting 75 g of glucose in the fasting state. SIFT-MS enabled real-time quantification of ammonia, methanol, ethanol, propanol, formaldehyde, acetaldehyde, isoprene and acetone. Following glucose ingestion, blood glucose and trace compound levels were measured every 30 min for 2 h. All the above compounds, except formaldehyde, were detected at the expected levels in exhaled breath of all volunteers; all the above compounds, except isoprene, were detected in the collection bag. Ammonia, methanol and ethanol were present at lower levels in the bag than in the breath. The aldehydes were present at higher levels in the bag than in breath. The blood glucose increased to a peak about 1 h post-ingestion, but this change was not obviously correlated with temporal changes in any of the compounds in breath or emitted by skin, except for acetone. The decrease in breath acetone was closely mirrored by skin-emitted acetone in three volunteers. Breath and skin acetone also clearly change with blood glucose and further work may ultimately enable inferences to be drawn of the blood glucose concentration from skin or breath measurements in type 1 diabetes.
  Rapid Communications in Mass Spectrometry 02/2008; 22(4):526-32. · 2.79 Impact Factor