OZONE EFFECT ON RESPIRATORY TRACT MUCUS AND PERMEABILITY

在健康受试者中，呼吸道膜将被放射性标记 使用不溶性氧化铁颗粒或可溶性DTPN颗粒来 分别通过以下方法测量粘液清除或膜通透性 使用伽马相机成像的非侵入性技术。急性呼吸窘迫综合征的影响 而连续暴露在0.2或0.4ppm水平的臭氧的时间将是 评估过了。目前，肺机械治疗的阈值浓度 变化和主观不适在0.3至0.4ppm之间。这些 研究将在以下三个层面提供有关臭氧影响的新信息 年被确定为损伤焦点的呼吸道 动物模型：1)气管和大支气管；2)小支气管和 3)远端细支气管和近端肺泡管； 肺泡。这些技术对中央呼吸道的改变很敏感。 外周肺粘液转运速度与粘液纤毛功能 以及基底部、肺中部和肺组织内溶质吸收的变化。 肺尖区。急性和再暴露期的结果 臭氧将支持或挑战关于气管和支气管壁 粘液和/或呼吸道通透性是导致 暴露在臭氧中的人立即产生的机械变化，以及 随后滞留与同时发生的这些更改 再次暴露在臭氧中。粘膜功能的测量可能会超过 机械性能标准指数在识别中的敏感性 低水平臭氧暴露下的组织损伤(低于0.2ppm)，因此 要求重新评估人类体内的臭氧阈值水平。现在 调查仅限于健康的受试者(非吸烟者) 臭氧暴露期间的间歇轻度运动，但未来的研究将 包括肺部疾病组。一旦粘液膜效应 确定的，与作用机制和改善有关的研究 臭氧效应是可以引发的。

In healthy subjects the respiratory tract membranes will be radio-labeled with either insoluble iron oxide particles or soluble DTPN particles to measure mucus clearance or membrane permeability, respectively, by non-invasive techniques using gamma camera imaging. The influence of acute and consecutive exposure periods to ozone at 0.2 or 0.4 ppm levels will be assessed. Presently, the threshold concentration for lung mechanical changes and subjective discomfort is between 0.3 and 0.4 ppm. These studies will provide new information on ozone effects at three levels of the respiratory tract which have been identified as foci of injury in animal models: 1) Trachea and large bronchi; 2) Small bronchi and bronchioles; and 3) Distal Bronchioles and proximal alveolar ducts and alveoli. The techniques are sensitive to alterations in central airway velocities of mucus transport and mucociliary function of peripheral lung airways, and to changes in solute absorption within basal, mid-lung and apical lung regions. The results of acute and re-exposure periods with ozone will either support or challenge the hypotheses that tracheobronchial mucus and/or respiratory tract permeability are contributing factors for the immediate mechanical changes induced in man exposed to ozone, and the subsequent detention of these changes that occurs co-incident with re-exposure to ozone. Measurements of mucus membrane function may surpass the sensitivity of standard indices of mechanical function in identifying tissue damage at low levels of ozone exposure (less than 0.2 ppm), and thus require re-evaluation of the ozone threshold level in man. The present investigation is confined to healthy subjects (non-smokers) who will have intervals of light exercise during ozone exposures, but future studies will include pulmonary disease groups. Once mucus membrane effects have been determined, studies related to mechanisms of action and amelioration of ozone effects can be initiated.