Contractile properties of single permeabilized muscle fibers from congenital cleft palates and normal palates of Spanish goats.
BACKGROUND
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Hanes
Michael C
MC
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.
Weinzweig
Jeffrey
J
Kuzon
William M
WM
Panter
Kip E
KE
Buchman
Steven R
SR
Faulkner
John A
JA
Yu
Deborah
D
Cederna
Paul S
PS
Larkin
Lisa M
LM
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002972:Cleft Palate / Q000473:pathology* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D006041:Goats; D007150:Immunohistochemistry; D007537:Isometric Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000502:physiology; D009924:Organ Culture Techniques; D010156:Palatal Muscles / Q000473:pathology* / Q000502:physiology; D011336:Probability; D011897:Random Allocation; D012016:Reference Values; D012680:Sensitivity and Specificity; D013030:Spain; D018709:Statistics, Nonparametric