Curette fat sculpture in rhytidectomy: improving the nasolabial and labiomandibular folds

The nasolabial and labiomandibular folds develop with facial aging by an anterior caudal descent of the fat prominences of the same name. Young patients with minimal folding can be corrected by substances inserted in the fold; however, this and other techniques have failed satisfactorily to improve the folds naturally and permanently. Identification of the prominences and removal of the fat superficial to the skin by curettes have proven safe and effective and superior to fat suction. Complications include small hematomas and visible depressions in the sculpted areas. There was no nerve or skin injury. Follow-up of this technique (an improvement of a previous technique) is 3 1/2 years.     

Anatomic variations of the nasolabial fold.

The nasolabial fold varies considerably from person to person. Three main groups may be distinguished: convex, concave, and straight. It is the muscles of smiling that are directly responsible for the shape and depth of the fold, and in their absence of function, as in facial palsy, the nasolabial fold disappears. Cadavers were selected in accordance with the nasolabial fold they presented and were dissected to analyze the difference in underlying anatomy between one fold shape in one cadaver and another fold shape in another. The study demonstrates that the nasolabial fold is the result of a conflict between soft and dynamic tissues of the middle face or an interaction between the skin and fat envelope on one side and the underlying muscles on the other. The greater this conflict, the more excess there is of cheek skin and the more pronounced a nasolabial fold. The mechanism that creates the nasolabial fold and the anatomy of the fold are described in this paper.     

Restoration of the upper lip and nasolabial area by means of an intraoral approach

Superomedial repositioning of the superficial musculoaponeurotic system (SMAS) in the upper lip is accomplished by means of intraoral incisions. The procedure reestablishes the convexity of the lateral vermilion border, elevates the upper lip, and restores a more youthful appearance to the upper-lip profile. Depth of the nasolabial folds are reduced. We have performed this procedure on 14 patients. Follow-up intervals range from 6 to 20 months, averaging 14 months. All patients received concomitant rhytidectomy; usual operative time was increased by 20 minutes. Results have been rated good to excellent by patients and surgeons. There have been no recurrences of nasolabial fold deepening or upper lip depression, and there have been no complications. In selected patients, this procedure, along with rhytidectomy, may provide a more youthful appearance.     

A study of the long-term effect of malar fat repositioning in face lift surgery: short-term success but long-term failure

In 1990, the author reported on a series of 403 cases of deep plane face lifts, the first published technique describing the repositioning of the cheek fat, known as malar fat, in face lift surgery. This study examines the long-term results of 20 of the original series in an attempt to determine what areas of the rejuvenated face (specifically, the malar fat) showed long-term improvement. The results were judged by comparing the preoperative and long-term postoperative views in a half-and-half same-side hemiface photograph. The anatomy of the jawline (superficial musculoaponeurotic system [SMAS]), the nasolabial fold (malar fat), and the periorbital diameter were evaluated. The results confirmed that repositioning of the SMAS remained for longer than improvement in the nasolabial fold and that the vertical diameter of the periorbit did not change at all. The early results of malar fat repositioning shown at 1 to 2 years were successful, but the long-term results showed failure of the early improvement, manifested by recurrence of the nasolabial folds. There was, however, continuation of the improved results of the forehead lift and SMAS maneuvers of the original procedure. The conclusion is that only a direct excision will produce a permanent correction of the aging nasolabial fold.     

Subperiosteal approach as an improved concept for correction of the aging face

A harmonious facial appearance is determined by a balanced relationship among all tissues of the face. With advancing age, balance is lost among the bone, muscle, fat, and skin as progressive changes occur in their volume, shape, position, and consistency. Study of clinical cases and fresh cadaver dissections has led to better understanding of the superficial musculoaponeurotic system (SMAS) and its relationship with the facial muscles and their bony insertions. From these anatomic studies we have developed an improved concept of rhytidectomy with the subperiosteal detachment of all soft tissues from the orbit, upper maxilla, malar bone, and nose. Following this detachment, the soft tissues of the cheek, forehead, jowls, nasolabial folds, lateral canthus, and eyebrows can be lifted to reestablish their youthful relationship with the underlying skeleton. Our 4-year experience includes 105 patients. Sixty percent of these patients were admitted to the hospital and had their procedure under general anesthesia; forty percent, however, had their procedure in an outpatient setting requiring only local anesthesia (lidocaine hydrochloride 1% plus epinephrine) and intravenous sedation (midazolam, ketamine). Complications have been minimal except for temporary paralysis of the frontal nerve in seven patients; guidelines for prevention have subsequently been developed. The subperiosteal rhytidectomy is excellent and appears more natural for rejuvenation of the upper and central face, eyebrows, periorbita, external canthus, cheeks, and nasolabial fold.     

Rhytidectomy and the nasolabial fold.

I describe a technical modification in the Skoog face lift procedure that releases the deep attachments of the SMAS to the muscles of facial expression for maximal mobility of the medial cheek yet elevates the cheek flap as a composite of skin, subcutaneous tissue, and SMAS to enhance skin perfusion. My results with the procedure in 100 patients are analyzed by using functional zones of the nasolabial fold corresponding to underlying musculature and a simple grading system based on preoperative and postoperative photographs. Marked improvement in the nasolabial fold was noted in over 80 percent of patients by 6 and 12 months postoperatively. This effect seemed to last up to 4 years.     

The high-superficial musculoaponeurotic system technique in facial rejuvenation: an update

The medical charts of 267 patients who had primary high-superficial musculoaponeurotic system (SMAS) rhytidectomies were reviewed. The depth of the nasolabial fold was used as an indicator of the degree of descent of the subcutaneous cheek mass, as a guide in procedure selection, and as a method of judging the operative results. Fold depth was assigned a score of 0 to 3, with 3 being most severe. According to their preoperative fold depth, patients were operated on using one of three variants of the high-SMAS technique: sub-SMAS dissection up to the nasolabial fold, sub-SMAS dissection up to the nasolabial fold plus transnasal SMAS graft, or sub-SMAS dissection across the nasolabial fold. An independent trained observer rated the postoperative fold depth in each case from photographs taken at the 6-month follow-up visit. Of patients with fold scores of 2 or 3, 97 percent (183 of 189 patients) showed visible improvement in nasolabial crease depth after the operation.     

Evaluation of a technique designed to correct nasolabial folds.

This is a long-term follow-up of correction of nasolabial folds in conjunction with face lift that was first published in 1987. In the last 200 face lifts, nasolabial lipectomy has been carried out in 90 percent. Refinements and extensions of the procedure are also described with case illustrations.     

The nasolabial fold: an attempt at synthesis

There is now enough information on the nasolabial fold to try to synthesize it with other well-known structures, such as the dermal terminations of the facial muscles, the superficial musculoaponeurotic system, and the fat pad. Rest dynamic equilibrium is a good concept to use to understand the nasolabial fold, because the nasolabial fold is not a passive, definitive structure, but an evolutive border whose limits depend on the absence or presence of fibromuscular terminations crossing the superficial musculoaponeurotic system of the cheek. A simple photograph of two men will help illustrate the difference between the convex and the concave nasolabial fold.     

Histochemistry of glycoconjugates in the goat nasolabial skin with special reference to eccrine glands

The histochemistry of glycoconjugates in the nasolabial skin of the goat has been studied by means of a series of selected methods of light microscopy. The epidermis of the nasolabial skin was found to contain neutral and acid glycoconjugates with different saccharide residues. The secretory epithelial cells and secretory substances of the sebaceous glands contained primarily neutral glycoconjugates, whereas those of the apocrine glands involved largely strongly acidic and neutral glycoconjugates. In the epithelial cells and secretory substances of the nasolabial eccrine glands, glycoconjugates involved were characteristically strongly neutral but weakly acidic in nature. From the present results, the histophysiological significance of glycoconjugates in the particular histologic structures of the nasolabial skin has been discussed with special reference to the functions of this particular skin type in the goat.     

Correction of the nasolabial fold: extended SMAS dissection with periosteal fixation.

The nasolabial fold has defied satisfactory correction with the face lift operation. This is despite variations of the SMAS technique over the last 20 years. In this study, the nasolabial fold is shown to be part of the overall aging deformity that affects the cheek and perioral region. The key to surgical correction, not previously appreciated, is the complete release of the anterior SMAS from the zygoma and zygomaticus major muscle. This allows a dramatic mobilization of the nasolabial fold without tension. The advanced SMAS is then reattached to the zygomatic periosteum by a series of permanent sutures. Each suture, by its location and direction of lift, corrects one of the four nasolabial regions including the jowl. The relevant anatomy is reviewed and the safety of the procedure is assessed in a personal series of 135 patients. It is concluded that the two principles of this technique, i.e., complete SMAS release and reattachment to the zygoma, safely and effectively achieve a natural-appearing rejuvenation of the cheek and nasolabial fold.     

Progress in fold recognition

The prediction experiment reveals that fold recognition has become a powerful tool in structural biology. We applied our fold recognition technique to 13 target sequences. In two cases, replication terminating protein and prosequence of subtilisin, the predicted structures are very similar to the experimentally determined folds. For the first time, in a public blind test, the unknown structures of proteins have been predicted ahead of experiment to an accuracy approaching molecular detail. In two other cases the approximate folds have been predicted correctly. According to the assessors there were 12 recognizable folds among the target proteins. In our postprediction analysis we find that in 7 cases our fold recognition technique is successful. In several of the remaining cases the predicted folds have interesting features in common with the experimental results. We present our procedure, discuss the results, and comment on several fundamental and technical problems encountered in fold recognition. © 1995 Wiley-Liss, Inc.     

Fold usage on genomes and protein fold evolution

We review fold usage on completed genomes to explore protein structure evolution. The patterns of presence or absence of folds on genomes gives us insights into the relationships between folds, the age of different folds and how we have arrived at the set of folds we see today. We examine the relationships between different measures which describe protein fold usage, such as the number of copies of a fold per genome, the number of families per fold, and the number of genomes a fold occurs on. We obtained these measures of fold usage by searching for the structural domains on 157 completed genome sequences from all three kingdoms of life. In our comparisons of these measures we found that bacteria have relatively more distinct folds on their genomes than archaea. Eukaryotes were found to have many more copies of a fold on their genomes. If we separate out the different fold classes, the alpha/beta class has relatively fewer distinct folds on large genomes, more copies of a fold on bacteria and more folds occurring in all three kingdoms simultaneously. These results possibly indicate that most alpha/beta folds originated earlier than other folds. The expected power law distribution is observed for copies of a fold per genome and we found a similar distribution for the number of families per fold. However, a more complicated distribution appears for fold occurrence across genomes, which strongly depends on fold class and kingdom. We also show that there is not a clear relationship between the three measures of fold usage. A fold which occurs on many genomes does not necessarily have many copies on each genome. Similarly, folds with many copies do not necessarily have many families or vice versa.     

Composite upper lip repair with V-Y advancement flaps

In two patients, large but superficial partial-thickness resections of lateral upper lip have been repaired by composite island cutaneous flaps. Upper lip and nasolabial fold flaps, along with lateral vermilion, were advanced and closed in a V-Y manner leaving inconspicuous scars and no contour deformity.     

The midface sling: a new technique to rejuvenate the midface

In the early 1990s, the midface became the focus of facial rejuvenation, and various techniques effected elevation by plicating, or on, the midface. Recent analyses of facial aging demonstrate that selective ptosis of the midfacial tissues lateral to the nasolabial fold results in an infraorbital hollow and deepening of the nasolabial fold. Therefore, the authors propose that the midface, from the lower portion of the cheek mass, will result in superior midface positioning. Since 1996, the authors have elevated the midface in select patients by placing a sling of prosthetic (Gore-Tex) or autogenous (tendon or fascia) material through the cheek mass. The sling is secured medially to the infraorbital rim using a nonabsorbable periosteal suture or a mechanical anchor. As variable tension is applied laterally toward the superficial temporal fascia, the sling functions as a fulcrum to return the cheek mass to a more youthful anatomical position. Elevating the cheek mass in this fashion fills the infraorbital hollow and results in amelioration of deep nasolabial folds and jowling. With a mean follow-up of 18 months, 50 patients treated with the midface sling report satisfaction with the procedure. There have been no instances of nerve damage, infection, or hematoma in the midface. None of the slings have required removal and ectropion has not occurred. Because of postoperative asymmetry in one patient, additional elevation of the ipsilateral cheek mass was performed by increasing the tension on the lateral cheek portion of the midface sling. Mathematical models demonstrate the biomechanical superiority of lift through the use of multiple vectors as compared with linear pull techniques. In this fashion, the midface sling supports the cheek mass, providing rapid, simple, and secure elevation. Because of the limited subcutaneous dissection, there is a reduced risk of facial nerve damage and cutaneous vascular compromise. Unlike with other techniques, the lateral portion of the sling may be easily identified through a small incision in the temporal scalp, facilitating subsequent postoperative adjustment of the midface suspension. Furthermore, because the entire cheek mass is permanently supported with an inelastic sling, the results may last longer than those with techniques that rely on sutures to plicate or lift portions of the superficial musculoaponeurotic system.     

Quantifying the similarities within fold space

We have used GRATH, a graph-based structure comparison algorithm, to map the similarities between the different folds observed in the CATH domain structure database. Statistical analysis of the distributions of the fold similarities has allowed us to assess the significance for any similarity. Therefore we have examined whether it is best to represent folds as discrete entities or whether, in fact, a more accurate model would be a continuum wherein folds overlap via common motifs. To do this we have introduced a new statistical measure of fold similarity, termed gregariousness. For a particular fold, gregariousness measures how many other folds have a significant structural overlap with that fold, typically comprising 40% or more of the larger structure. Gregarious folds often contain commonly occurring super-secondary structural motifs, such as beta-meanders, greek keys, alpha-beta plait motifs or alpha-hairpins, which are matching similar motifs in other folds. Apart from one example, all the most gregarious folds matching 20% or more of the other folds in the database, are alpha-beta proteins. They also occur in highly populated architectural regions of fold space, adopting sandwich-like arrangements containing two or more layers of alpha-helices and beta-strands.Domains that exhibit a low gregariousness, are those that have very distinctive folds, with few common motifs or motifs that are packed in unusual arrangements. Most of the superhelices exhibit low gregariousness despite containing some commonly occurring super-secondary structural motifs. In these folds, these common motifs are combined in an unusual way and represent a small proportion of the fold (<10%). Our results suggest that fold space may be considered as continuous for some architectural arrangements (e.g. alpha-beta sandwiches), in that super-secondary motifs can be used to link neighbouring fold groups. However, in other regions of fold space much more discrete topologies are observed with little similarity between folds.     

Helix-bundle membrane protein fold templates

In the fold recognition approach to structure prediction, a sequence is tested for compatibility with an already known fold. For membrane proteins, however, few folds have been determined experimentally. Here the feasibility of computing the vast majority of likely membrane protein folds is tested. The results indicate that conformation space can be effectively sampled for small numbers of helices. The vast majority of potential monomeric membrane protein structures can be represented by about 30-folds for three helices, but increases exponentially to about 1,500,000 folds for seven helices. The generated folds could serve as templates for fold recognition or as starting points for conformational searches that are well distributed throughout conformation space.     

Recurring structural motifs in proteins with different functions

BACKGROUND: Structures that have diverged from a common ancestor often retain functional and sequence similarity, although the latter may be very reduced. Even so, the overall fold of the structure is generally highly conserved. Now however, several have been identified of proteins that have been identified that have different functions but which have converged to a similar fold. These proteins will also have low sequence identities. RESULTS: By comparing the complete structure databank against itself, using sequence and structure alignment techniques, we have been able to identify six new examples of structurally related folds that have no apparent sequence or functional similarity. These related proteins include a family of crambin-like folds and a family of ferredoxin II folds. We found that all the similarities between structures are present in small proteins and occur as motifs within the core of a larger protein. CONCLUSION: The low sequence similarity and the lack of any obvious functional relationship between proteins with similar structures suggest that the proteins have diverged from independent ancestors. The similarities may therefore be of interest for understanding the various stereochemical and physical criteria that operate to generate a favourable fold.     

Periosteal suspension of the lower eyelid and cheek following subciliary exposure of facial fractures

Following craniofacial procedures that involve stripping of the periosteum and soft tissue over the zygomatic maxillary complex, descent of soft tissue with a decrease in anterior projection over the malar area and increase in fullness in the nasolabial fold have been seen to be a problem by these authors. Simple repositioning of the soft tissues to their normal anatomic position may be used to alleviate this problem.     

Type II restriction endonuclease R.Hpy188I belongs to the GIY-YIG nuclease superfamily,but exhibits an unusual active site

Background  

Catalytic domains of Type II restriction endonucleases (REases) belong to a few unrelated three-dimensional folds. While the PD-(D/E)XK fold is most common among these enzymes, crystal structures have been also determined for single representatives of two other folds: PLD (R.BfiI) and half-pipe (R.PabI). Bioinformatics analyses supported by mutagenesis experiments suggested that some REases belong to the HNH fold (e.g. R.KpnI), and that a small group represented by R.Eco29kI belongs to the GIY-YIG fold. However, for a large fraction of REases with known sequences, the three-dimensional fold and the architecture of the active site remain unknown, mostly due to extreme sequence divergence that hampers detection of homology to enzymes with known folds.