Hanes Michael C, Weinzweig Jeffrey, Kuzon William M, Panter Kip E, Buchman Steven R, Faulkner John A, Yu Deborah, Cederna Paul S, Larkin Lisa M
Ann Arbor, Mich.; Burlington, Mass.; and Logan, Utah From the Section of Plastic Surgery, Division of Geriatric Medicine, and Institute of Gerontology, University of Michigan; Department of Plastic Surgery, Lahey Clinic; and the Poisonous Plant Research Laboratory, USDA Agricultural Research Service.
Plast Reconstr Surg. 2007 May;119(6):1685-1694. doi: 10.1097/01.prs.0000258832.84261.37.
Analysis of the composition of muscle fibers constituent to a cleft palate could provide significant insight into the cause of velopharyngeal inadequacy. The authors hypothesized that levator veli palatini muscle dysfunction inherent to cleft palates could affect the timing and outcome of cleft palate repair.
Single, permeabilized muscle fibers from levator veli palatini muscles of three normal (n = 19 fibers) and three chemically induced congenital cleft palates (n = 21 fibers) of 14-month-old goats were isolated, and contractile properties were evaluated. The maximum isometric force and rate constants of tension redevelopment (ktr) were measured, and the specific force and normalized power were calculated for each fiber.
The ktr measures indicate that cleft fibers are predominantly fast-fatigable; normal fibers are slow fatigue-resistant: after a 10-minute isometric contraction, fibers from cleft palates had a loss of force 16 percent greater than that from normal palates (p = 0.0001). The cross-sectional areas of the fibers from cleft palates (2750 +/- 209 microm2) were greater (p = 0.05) than those from normal palates (2226 +/- 143 microm2). Specific forces did not differ between the two groups. Maximum normalized power of fibers from cleft palates (11.05 +/- 1.82 W/l) was greater (p = 0.0001) than fibers from normal palates (1.60 +/- 0.12 W/l).
There are clear physiologic differences in single muscle fibers from cleft palates and normal palates: cleft palate fibers are physiologically fast, have greater fatigability, and have greater power production. Detection of functional and/or fiber type differences in muscles of cleft palates may provide preoperative identification of a patient's susceptibility to velopharyngeal inadequacy and permit early surgical intervention to correct this clinical condition.
分析腭裂相关肌肉纤维的组成，可能为腭咽闭合不全的病因提供重要见解。作者推测，腭裂固有的腭帆提肌功能障碍可能会影响腭裂修复的时机和效果。
从14月龄山羊的三块正常腭帆提肌（n = 19根纤维）和三块化学诱导的先天性腭裂腭帆提肌（n = 21根纤维）中分离出单个的、通透的肌肉纤维，并评估其收缩特性。测量最大等长力和张力再发展速率常数（ktr），并计算每根纤维的比力和归一化功率。
ktr测量结果表明，腭裂纤维主要是快速易疲劳型；正常纤维是慢速抗疲劳型：在10分钟等长收缩后，腭裂纤维的力量损失比正常腭纤维大16%（p = 0.0001）。腭裂纤维的横截面积（2750 +/- 209平方微米）大于正常腭纤维（2226 +/- 143平方微米）（p = 0.05）。两组之间的比力没有差异。腭裂纤维的最大归一化功率（11.05 +/- 1.82瓦/升）大于正常腭纤维（1.60 +/- 0.12瓦/升）（p = 0.0001）。
腭裂和正常腭的单根肌肉纤维存在明显的生理差异：腭裂纤维在生理上是快速型的，具有更大的易疲劳性和更大的功率产生。检测腭裂肌肉中的功能和/或纤维类型差异，可能有助于术前识别患者发生腭咽闭合不全的易感性，并允许早期进行手术干预以纠正这种临床状况。
