Immunohistochemical analysis of orbicularis oris muscle fiber distribution at the philtrum in healthy infants.

OBJECTIVE: To characterize the fiber-type distribution of the orbicularis oris muscle at the philtrum in healthy infants by immunohistochemistry and examine the relationship between orbicularis oris and philtrum structure. METHODS: Samples of the upper lip were obtained from two infant cadavers. Serial sagittal sections were obtained at the midline of the philtral dimple, unilateral philtral ridge, and the lateral side. Three sections from each site were prepared for immunohistochemical staining using myosin heavy chain fast fiber (MHCf) and myosin heavy chain slow fiber (MHCs) antibodies to determine the ratio of fast to slow skeletal muscle fibers. RESULTS: The ratio of fast to slow muscle fibers differed significantly among the superficial orbicularis oris muscle (98.30%:1.13%), deep pars peripheralis (95.30%:3.14%), and deep pars marginalis (91.31%:5.74%), with a significantly higher percentage of slow fibers in the pars marginalis compared to pars peripheralis (P=0.002) and fast fibers in the superficial muscle compared to pars marginalis and peripheralis (both P=0.000). Similarly, the fast:slow fiber ratio differed among the superficial philtral dimple (95.88%:2.41%), superficial philtral ridge (98.52%:1.11%), and superficial midlateral philtral ridge (99.07%:0.66%), with a higher percentage of fast fibers higher on the lateral side of the superficial philtral ridge than at the philtral ridge (P=0.030) and higher at the philtral ridge than the philtral dimple (P=0.001). The fast:slow fiber ratio did not differ within the pars peripheralis at the philtral dimple (93.94%:4.19%), philtral ridge (94.49%:3.84%), and lateral philtral ridge (95.79%:2.70%) (all P>0.05). CONCLUSIONS: Philtum structure is likely determined in part by the distribution of muscle fiber types among philtral dimple, ridge, and lateral side. These differences should be considered in cleft lip repair.

Targeted gene transfer into rat facial muscles by nanosecond pulsed laser-induced stress waves.

We investigate the feasibility of using nanosecond pulsed laser-induced stress waves (LISWs) for gene transfer into rat facial muscles. LISWs are generated by irradiating a black natural rubber disk placed on the target tissue with nanosecond pulsed laser light from the second harmonics (532 nm) of a Q-switched Nd:YAG laser, which is widely used in head and neck surgery and proven to be safe. After injection of plasmid deoxyribose nucleic acid (DNA) coding for Lac Z into rat facial muscles, pulsed laser is used to irradiate the laser target on the skin surface without incision or exposure of muscles. Lac Z expression is detected by X-gal staining of excised rat facial skin and muscles. Strong Lac Z expression is observed seven days after gene transfer, and sustained for up to 14 days. Gene transfer is achieved in facial muscles several millimeters deep from the surface. Gene expression is localized to the tissue exposed to LISWs. No tissue damage from LISWs is observed. LISW is a promising nonviral target gene transfer method because of its high spatial controllability, easy applicability, and minimal invasiveness. Gene transfer using LISW to produce therapeutic proteins such as growth factors could be used to treat nerve injury and paralysis.

[A successive study of histopathological changes in unilateral facial muscle denervation].

OBJECTIVE: To observe the histopathological changes in unilateral facial muscle denervation. METHODS: Gomori trichrome stain, acridine orange (AO) fluorescence, enzyme-histochemistry and immunohistochemistry techniques were used for studying mitochondria, nuclei acid concentration, enzymatic activity and contraction protein expression of facial muscle in different denervation period. RESULTS: Mitochondrian function, enzymatic activity and contraction protein expression of facial muscle denervation increased in the first two weeks, then declined till 6 months. Myofiber's histotype began to transform in 1 month after denervation. Type-grouping was obvious in 6 month. Regeneration myofibers were also seen at this time. CONCLUSIONS: Unilateral facial muscles become atrophy after denervation. They have proliferating tendency from 2 month to 6 month. Therefore, within 1 month after denervation measures to benefit atrophy will be more effective.

Pain, allodynia, and serum serotonin level in orofacial pain of muscular origin.

AIMS: This study was conducted to investigate the serum level of serotonin (S-5-HT) in patients with temporomandibular disorders (TMD) of muscular origin, i.e., localized myalgia, and to compare it to that found in healthy individuals and patients with fibromyalgia. A second aim was to investigate the association between S-5-HT and pain parameters. METHODS: Twenty patients with localized myalgia participated in the study. Twenty age- and gender-matched healthy individuals and twenty patients with fibromyalgia served as controls. The participants were examined clinically as to the condition of the temporomandibular region and S-5-HT. RESULTS: The levels of S-5-HT did not differ significantly between the groups. However, in patients with localized myalgia there was a negative correlation between S-5-HT and tenderness of the temporomandibular muscles. CONCLUSION: The results of this study indicate that allodynia of orofacial muscles in patients with TMD is significantly related to S-5-HT concentration.

Hyaluronan localization in tissues of the mouse posterior eye wall: absence in the interphotoreceptor matrix.

The distribution of hyaluronan (HA) in the posterior eye wall from the vitreous through the sclera, with special consideration to localization in the retina and interphotoreceptor matrix (IPM), was evaluated in mouse tissues using an HA specific probe (bHABC, biotinylated hyaluronan binding complex). The vitreous body was positive for HA, as was Bruch's membrane, expansive areas within the choroid, sclera and perimysial connective tissue of extraocular muscle. No HA-staining was detected in the IPM or in any other retina layer except for the basal lamina (inner limiting membrane of the retina) which abuts the vitreous. Predigestion of sections with trypsin or chondroitinase ABC before bHABC application did not produce additional HA-staining in the retina or IPM.

Two fibromuscular transverse ligaments related to the levator palpebrae superioris: Whitnall's ligament and an intermuscular transverse ligament.

BACKGROUND: This study was performed to reinvestigate the detailed anatomy of the connective tissues related to the levator palpebrae superioris (LPS). MATERIALS AND METHODS: One hundred and twenty human orbits were prepared macroscopically or with the help of an operational microscope. Connective tissues related to the LPS were measured, removed, and prepared for histology. Different staining procedures including immunohistochemistry for alpha-smooth muscle actin were applied to analyze the quality of these tissues. RESULTS: Preparation consistently revealed two definite fibromuscular transverse ligaments related to the LPS, i.e., Whitnall's ligament (WL) and a definite intermuscular transverse ligament (ITL) underlying the LPS. The ITL exhibited a greater anterio-posterior extension than WL. In sagittal section, the ITL was observed slightly more posterior in the orbit than WL. Histologically, both ligaments consisted of collagenous fibers, elastic fibers, and smooth muscle fibers. WL was connected with the LPS by sagittal fibroelastic connecting strands. CONCLUSIONS: Two transverse ligaments of fibromuscular tissue, WL and the ITL, form a sleeve superior and inferior to the LPS. This sling is supposed to assist the LPS in its action and should be preserved at ptosis surgery.

Fetal myosin heavy chain increases in human masseter muscle during aging.

Biochemical, immunohistochemical and molecular biological methods were used to detect fetal myosin heavy chain (MyHC) in the human masseter of elderly and young subjects. Samples from the elderly subjects contained larger amounts of fetal MyHC than those of young adults. Only a very small amount of embryonic MyHC could be detected in both age groups. Embryonic and fetal MyHCs were never detected in the control adult orofacial, limb and trunk muscles. Polymerase chain reaction (PCR) analysis revealed the presence of fetal mRNA sequences in elderly and young masseter muscles. We conclude that fetal MyHC is present in the human masseter throughout the life span and that there is an increase in the relative amount of this protein with age.

Differences in myosin composition between human oro-facial, masticatory and limb muscles: enzyme-, immunohisto- and biochemical studies.

Immunohistochemistry was used to determine the myosin composition of defined fibre types of three embryologically different adult muscles, the oro-facial, masseter and limb muscles. In addition, the myosin composition in whole muscle specimens was analysed with biochemical methods. Both similarities and differences between muscles in the content of myosin heavy chains and myosin light chains were found. Nevertheless, each muscle had its own distinct identity. Our results indicated the presence of a previously undetected fast myosin heavy chain isoform in the oro-facial type II fibre population, tentatively termed 'fast F'. The masseter contained aberrant myosin isoforms, such as foetal myosin heavy chain and alpha-cardiac myosin heavy chain and unique combinations of myosin heavy chain isoforms which were not found in the limb or oro-facial muscles. The type IM and IIC fibres coexpressed slow and fast A myosin heavy chains in the oro-facial and limb muscles but slow and a fast B like myosin heavy chain in the masseter. While single oro-facial and limb muscle fibres contained one or two myosin heavy chain types, single masseter fibres coexpressed up to four different myosin heavy chain isoforms. Describing the fibres according to their expression of myosin heavy chain isozymes, up to five fibre types could be distinguished in the oro-facial and limb muscles and eight in the masseter. Oro-facial and limb muscles expressed five myosin light chains, MLC1S, MLC2S, MLC1F, MLC2F and MLC3F, and the masseter four, MLC1S, MLC2S, MLC1F, and, in addition, an embryonic myosin light chain, MLC1emb, which is usually not present in normal adult skeletal muscle. These results probably reflect the way the muscles have evolved to meet the specialized functional requirements imposed upon them and are in agreement with the previously proposed concept that jaw and limb muscles belong to two distinct allotypes.