Quantification of the three-dimensional displacement of normal facial movement.

This study was undertaken to quantify 3-dimensional (3-D) facial movement in normal subjects, and to identify the individual axes in which this movement occurred. Displacement data on 42 subjects were collected and analyzed with the Expert Vision Motion Analysis System. The 3-D displacement was calculated by vectorially subtracting maximum marker movement from previously identified reference marker points. The 3-D range of normal facial movement was quantified, with the greatest displacement occurring during maximum smile. When the individual axes were examined, we found that most movement occurred in the vertical axes for the majority of expressions, followed by the anterior-posterior axis. These results may create an objective baseline from which disorders of the facial nerve, and hence, medical, surgical, and physiotherapy treatment interventions, can be analyzed in the future.

Temporalis muscle transfer for facial paralysis: a further refinement.

Facial nerve paralysis can occur due to failure of the central driving mechanism (nuclear or supranuclear pathology), failure of the conduit between the brainstem and the peripheral musculature (the facial nerve), or failure of the peripheral end organ (the neuromuscular system). Where the peripheral neuromuscular system fails, the options for dynamic reanimation include a regional muscle transfer driven by another ipsilateral cranial nerve, or a free muscle transfer driven by the contralateral facial nerve. Temporalis muscle transfer is an example of regional muscle transfer and has been used since early in the twentieth century. A further refinement, involving mobilization of the coronoid process of the mandible in continuity with the insertion of the temporalis muscle via a nasolabial fold approach, using fascial strips to re-create movement around the mouth, is presented.

Three-dimensional quantification of "still" points during normal facial movement.

This study investigated the 3-dimensional displacement of points on the face that were thought to be still during facial movement. These points are currently used to measure displacement of moving facial regions during assessment of normal facial movement and treatment interventions following facial nerve paralysis. It is, however, unknown if these places are "still" points. The Expert Vision Motion Analysis System was used to collect and analyze data on 42 normal subjects during facial movement. No point on the face was found to be still during facial expression. However, several points were present with very small movements for each individual expression. These were termed "reference" points. These small movements may be the result of system noise, physiological tremor, skin movement, or head-holder movement during facial expressions. Future studies of the displacement of the markers during facial movement in both normal subjects and patients with facial nerve paralysis may take into account the contribution of the "reference" point displacements to the overall facial movement.

The survival motor neuron protein in spinal muscular atrophy.

The 38 kDa survival motor neuron (SMN) protein is encoded by two ubiquitously expressed genes: telomeric SMN (SMN(T)) and centromeric SMN (SMN(C)). Mutations in SMN(T), but not SMN(C), cause proximal spinal muscular atrophy (SMA), an autosomal recessive disorder that results in loss of motor neurons. SMN is found in the cytoplasm and nucleus. The nuclear form is located in structures termed gems. Using a panel of anti-SMN antibodies, we demonstrate that the SMN protein is expressed from both the SMN(T) and SMN(C) genes. Western blot analysis of fibroblasts from SMA patients with various clinical severities of SMA showed a moderate reduction in the amount of SMN protein, particularly in type I (most severe) patients. Immunocytochemical analysis of SMA patient fibroblasts indicates a significant reduction in the number of gems in type I SMA patients and a correlation of the number of gems with clinical severity. This correlation to phenotype using primary fibroblasts may serve as a useful diagnostic tool in an easily accessible tissue. SMN is expressed at high levels in brain, kidney and liver, moderate levels in skeletal and cardiac muscle, and low levels in fibroblasts and lymphocytes. In SMA patients, the SMN level was moderately reduced in muscle and lymphoblasts. In contrast, SMN was expressed at high levels in spinal cord from normals and non-SMA disease controls, but was reduced 100-fold in spinal cord from type I patients. The marked reduction of SMN in type I SMA spinal cords is consistent with the features of this motor neuron disease. We suggest that disruption of SMN(T) in type I patients results in loss of SMN from motor neurons, resulting in the degeneration of these neurons.

Physical mapping at a potential X-linked retinitis pigmentosa locus (RP3) by pulsed-field gel electrophoresis.

A genetic locus (RP3) for X-linked retinitis pigmentosa (XLRP) has been assigned to Xp21 by genetic linkage studies and has been supported by two Xp21 male deletion patients with XLRP. RP3 appears to be the most centromeric of several positioned loci, including chronic granulomatous disease (CGD), McLeod phenotype (XK), and Duchenne muscular dystrophy (DMD). In one patient, BB, the X-chromosome deletion includes RP3 and extends to within the DMD locus. Using a DMD cDNA, the centromeric endpoint of this patient was cloned and used as a starting point for chromosome walking along a normal X chromosome. A single-copy probe, XH1.4, positioned near the centromeric junction but deleted in BB, was used along with a CGD cDNA probe to establish a refined long-range physical map. Both probes recognized a common SfiI fragment of 205 kb. As the CGD gene covers approximately 30-60 kb, the RP3 locus has been restricted to approximately 150-170 kb. A CpG island, potentially marking a new gene, was identified within the SfiI fragment at a position approximately 35 kb from the deletion endpoint in BB.