Validation of a method for collection and assay of pentane in the exhaled breath of the horse

The application of exhaled breath gas and exhaled breath condensate analysis in the investigation of the lower respiratory tract in veterinary medicine: A review

The analysis of biomarkers in exhaled breath (EB) and exhaled breath condensate (EBC) may allow non-invasive and repeatable assessment of respiratory health and disease in mammals. Compared to human medicine, however, research data from EB and EBC analysis in veterinary medicine are limited and more patient variables influencing concentrations of EB/EBC analytes may be present. In addition, variations in methodologies between studies may influence results. A comparison of the approaches used in veterinary research by different groups may aid in the identification of potentially reliable and repeatable biomarkers suitable for further investigation. To date, changes in acid-base status and increased concentrations of inflammatory mediators have been the main findings in studies of pulmonary disease states in animals. Whilst these biomarkers are unlikely to represent specific and sensitive diagnostic parameters, they do have potential application in monitoring disease progression and treatment response.

The oxidant/antioxidant equilibrium in horses

Since "free radical research" started in 1954, understanding the role of oxidants and antioxidants in physiological and pathological conditions has increased continuously. Oxidants are essentially generated by metabolic enzymes, inflammatory cells and mitochondrial electron leakage; they are indispensable for the cellular redox regulation and may, under certain conditions, have a pro-inflammatory stimulatory role. Endogenous and exogenous antioxidants counterbalance the oxidative processes and so maintain the oxidant/antioxidant equilibrium. Excessive oxidant generation or antioxidant insufficiency can lead to oxidative stress. The aims of this review are: (1) to provide an insight into the concept of the oxidant/antioxidant equilibrium by briefly introducing the oxidant and the antioxidant systems; (2) to describe how the oxidant/antioxidant equilibrium or oxidative stress can be evaluated in horses, and (3) to summarise current knowledge about oxidative stress in equine medicine and equine exercise physiology.

Current and future uses of breath analysis as a diagnostic tool

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.