THE USE OF THE INTERNAL PERIMETER TO COMPARE AIRWAY SIZE AND TO CALCULATE SMOOTH-MUSCLE SHORTENING
THE USE OF THE INTERNAL PERIMETER TO COMPARE AIRWAY SIZE AND TO CALCULATE SMOOTH-MUSCLE SHORTENING
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DOI：
10.1164/ajrccm/138.1.136
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发表时间：
1988-07-01
期刊：
影响因子：
--
通讯作者：
PARE, PD
中科院分区：
文献类型：
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作者：
JAMES, AL;HOGG, JC;PARE, PD
我们实验室之前的研究表明，当气道变窄时，由折叠上皮表面定义的气道内周长（Pi）保持不变。为了验证这一假设，我们用茶碱或萘酚处理切除肺叶的邻近切片，并确定这些肺切片中气道的尺寸。采用收缩气道（n=58）和松弛气道（n=55）的横切面测量上皮表面定义的Pi、管腔面积（Ai）、平滑肌层外缘定义的外周长（Pe）和外面积（Ae）。计算壁面积（WA = Ae - Ai）。收缩和放松气道的内周长频率分布无显著差异，当将壁面面积的平方根与Pi作对比时，收缩和放松气道的回归线几乎相同。计算“放松”外周长Per=[Pi2+(4.pi.WA)]0.5，并确定肌肉缩短百分比（PMS）： PMS=[(Per- pe)/Per] .times。100。我们得出结论，无论平滑肌松弛还是收缩，气道中的Pi和WA都是恒定的，Pi可以用作气道大小的标记，并且在受控条件下，可以用于计算给定气道中存在的平滑肌缩短。
Previous studies from our laboratory suggest that the internal airway perimeter (Pi) defined by the folded epithelial surface remains constant as the airways narrow. To test this hypothesis, we treated adjacent slices of resected lung lobes with either theophylline or carbachol and determined the dimensions of the airways in these lung slices. Transverse sections of contracted (n=58) and relaxed (n=55) airways were used to measure the Pi defined by the epithelial surface, lumen area (Ai), external perimeter (Pe) defined by the outer edge of the smooth muscle layer, and the external area (Ae). Wall area (WA = Ae - Ai) was calculated. The frequency distribution of internal perimeters was not significantly different for the contracted and relaxed airways, and when the square root of wall area was plotted against Pi, the regression lines for the contracted and relaxed airways were almost identical. The "relaxed" external perimeter was calculated Per=[Pi2+(4.pi.WA)]0.5 and the percentage of muscle shortening (PMS) was determined: PMS=[(Per-Pe)/Per] .times. 100. We conclude that Pi and WA are constant in airways whether the smooth muscle is relaxed or contracted and that Pi can be used as a marker of airway size and, under controlled conditions, can be used to calculate the smooth muscle shortening present in a given airway.