Abstract：
Isoprene is one of the most abundant and most frequently evaluated volatile organic compounds in exhaled breath. Recently, several individuals with background levels of exhaled isoprene have been identified. Here, case study data are provided for an individual, identified from a previous study, with this low prevalence phenotype. It is hypothesized that the individual will illustrate low levels of exhaled isoprene at rest and during exercise. At rest, the subject (7.1 ppb) shows background (μ= 14.2 ± 7.0 ppb) levels of exhaled isoprene while the control group illustrates significantly higher quantities (μ= 266.2 ± 72.3 ppb) via proton transfer reaction mass spectrometry (PTR-MS). The result, background levels of isoprene at rest, is verified by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) collections with the individual showing -3.6 ppb exhaled isoprene while the room background containedμ= -4.1 ± 0.1 ppb isoprene. As isoprene has been shown previously to increase at the initiation of exercise, exercise bike experiments were performed with the individual identified with low isoprene, yielding low and invariant levels of exhaled isoprene (μ= 6.6 ± 0.1 ppb) during the exercise while control subjects illustrated an approximate 2.5-fold increase (preμ= 286.3 ± 43.8 ppb, exerciseμ= 573.0 ± 147.8 ppb) in exhaled isoprene upon exercise start. Additionally, exhaled breath bag data showed a significant decrease in isoprene (delta post/pre, p = 0.0078) of the control group following the exercise regimen. Finally, TD-GC-MS results for exhaled isoprene from the individual\'s family (mother, father, sister and maternal grandmother) illustrated that the mother and father exhibited isoprene values (28.5 ppb, 77.2 ppb) below control samples 95% confidence interval (μ= 166.8 ± 43.3 ppb) while the individual\'s sister (182.0 ppb) was within the control range. These data provide evidence for a large dynamic range in exhaled isoprene in this family. Collectively, these results provide additional data surrounding the existence of a small population of individuals with background levels of exhaled isoprene.
摘要：
异戊二烯是呼出气体中最丰富和最频繁评估的挥发性有机化合物之一。最近,已经确定了几个具有呼出异戊二烯背景水平的个体。这里,案例研究数据是为个人提供的，从以前的研究中确定，这种低患病率表型。假设个体在休息和运动期间将显示出低水平的呼出异戊二烯。在休息时,受试者(7.1ppb)显示呼出异戊二烯的背景(μ=14.2±7.0ppb)水平,而对照组通过质子转移反应质谱(PTR-MS)显示显著更高的量(μ=266.2±72.3ppb)。结果,在休息时异戊二烯的背景水平，通过热脱附气相色谱质谱（TD-GC-MS）收集来验证，其中个体显示出呼出的-3.6ppb异戊二烯，而房间背景包含μ=-4.1±0.1ppb异戊二烯。由于先前已证明异戊二烯在运动开始时会增加，对鉴定为低异戊二烯的个体进行了健身车实验，在运动过程中产生低且不变的呼出异戊二烯水平（μ=6.6±0.1ppb），而对照受试者显示出大约2.5倍的增加（前μ=286.3±43.8ppb，运动开始时呼出的异戊二烯的运动μ=573.0±147.8ppb）。此外,呼出气袋数据显示异戊二烯显著减少(δpost/pre，运动方案后，对照组的p=0.0078）。最后,来自个体家庭的呼出异戊二烯的TD-GC-MS结果(母亲，父亲,姐姐和外婆)说明母亲和父亲表现出异戊二烯值(28.5ppb，77.2ppb）低于对照样品的95％置信区间（μ=166.8±43.3ppb），而个体的姐妹（182.0ppb）在对照范围内。这些数据为该家族中呼出的异戊二烯的大动态范围提供了证据。总的来说，这些结果提供了有关存在少量呼气异戊二烯背景水平的个体的额外数据。
