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1.
The ability to correct prominent nasolabial folds has remained a consistent weakness in facial rejuvenation surgery. Cadaveric studies were performed to evaluate differential properties of the superficial musculoaponeurotic system (SMAS) unit. We have found that the medial portion of the SMAS unit has a much more scattered, irregular collagen architecture and exhibits greater distensibility. Based on the regional differences in the physical properties and architecture of the SMAS, a face lift procedure is described in which the medial portion of the SMAS is resuspended, combined with aggressive temporal skin takeout in a pants-over-vest fashion. The procedure has been performed by the senior author in 89 patients. It is often combined with the "central" suspension and has provided more predictable results in this surgeon's hands.  相似文献   

2.
Although there are a multitude of techniques currently used for performing face lifts, there is no general agreement as to which, if any, of these techniques is most effective. There may never be a definitive answer to this issue because of the highly subjective nature of aesthetics, variability among surgeons, differences in patient anatomy, and specific patient desires. In an attempt to evaluate face lift techniques objectively, this study compares the rate of patients undergoing a tuck procedure after traditional SMAS (superficial musculoaponeurotic system) rhytidectomy to that of patients after deep plane rhytidectomy. A retrospective chart review was performed on all patients who underwent a tuck procedure following a face lift by the senior author (Kamer) between July of 1990 and January of 1997. There were 634 patients who electively underwent either a SMAS or deep plane type of rhytidectomy during the 6.5-year period; 48 patients subsequently underwent tuck operations, and adequate information was available on 44 patients. Of these, 43 were women and the average age was 57 years. The overall tuck rate from July of 1990 to January of 1997 was 7.5 percent. The tuck rate following SMAS rhytidectomy was 11.4 percent, and that following deep plane rhytidectomy was 3.3 percent. Therefore, a tuck was required 71 percent less frequently after a deep plane lift than after a SMAS lift. This was found to be a statistically significant difference with a p value of .0001 (Fisher's exact test, 2-tail). If the assumption is made that the need for a tuck procedure implies a less than optimal face lift, then the data of this study suggest that the deep plane technique is more effective than the SMAS technique.  相似文献   

3.
4.
The major histological characteristic of sun-damaged skin is the accumulation of an elastotic material that appears to replace collagen. This elastotic material consists primarily of elastin and histological studies suggest a large loss of collagen in the dermis of chronically sun-damaged skin. In this study, we examine the content and distribution of collagen and procollagen in sun-damaged human skin. The total collagen content of sun-damaged skin was 20% less than nonsolar-exposed skin (524 micrograms collagen per mg total protein in sun-damaged skin and 667 micrograms collagen per mg total protein in nonsolar-exposed skin). In addition, there was a 40% decrease in the content of intact amino propeptide moiety of type III procollagen in sun-damaged skin (0.68 U per 50 mg wet weight) as compared to nonsolar-exposed skin (1.12 U per 50 mg wet weight). The data suggest that this change in collagen content is due to increased degradation. The distribution of collagen in sun-damaged skin was examined by indirect immunofluorescence. Mild digestion of sun-damaged skin with elastase removed the elastin and revealed the presence of collagen in the elastotic material. Therefore, the elastin appears to mask the presence of collagen fibers in the dermis of sun-damaged skin.  相似文献   

5.
The ligament supporting the leading edge of birds' wings is a connective tissue structure with unusual morphologic and elastic features. Its center section is made of a highly extensible composite of elastin and collagen fibers and its two end sections of nearly inextensible pure collagen; these are joined end-to-end in short interdigitating junctions. Substantial forces are transmitted through the junctions showing that collagen and elastin are mechanically connected. The junctions and elastic segment are sufficiently strong that when the intact ligament is maximally strained, the point of failure is commonly in the collagenous segments or their attachments to the tissues of origin or insertion. Here we outline the morphology and describe static force-length properties of this ligament.  相似文献   

6.
BACKGROUND: Parotidectomies sometimes leave a conspicuous soft-tissue defect in the dorsal part of the cheek. METHODS: The authors present a modification of the standard technique of parotidectomy which is reserved for the surgical management of benign parotid tumors. The incision of the skin follows the guidelines for standard subcutaneous rhytidectomy with a modification according to the Redon incision. They use flaps of the subcutaneous musculoaponeurotic system (SMAS), which they fold or rotate in order to fill the soft-tissue defect following parotidectomy. The preparation of the skin and the SMAS in layers from the lateral to the medial aspect of the cheek does not affect the blood supply which comes from medially running vessels. RESULTS: Forty patients have been operated on using these modifications of the standard technique. A postoperative follow-up of more than one year could be controlled in 31 cases. Thirty patients showed an inconspicuous dorsal region of the cheek without a soft-tissue defect compared to the other side. They did not wish a secondary operation for an aesthetic improvement except two scar revisions. CONCLUSION: To date this surgical concept has proved its worth.  相似文献   

7.
Adhesion of cells to the extracellular matrix is mediated by structural glycoproteins such as fibronectin and laminin, and also elastonectin, whose role is to ensure binding of elastin fibers to cells. Interactions between elastin fibers and human skin fibroblasts cultured in a Rose chamber were investigated by using cinemicrography to observe elastin fiber attachment, detachment, and displacement over a five-day period. Elastin fiber displacement over the cell layer resulted in aggregation, which was measured using morphometry. The total number of isolated elastin fibers or aggregates decreased between 1 h and 8 h and remained stable thereafter. During the same time interval, significant decreases occurred in the numbers of isolated fibers and small aggregates (perimeter < 0.268 mm; surface area < 894 microns 2), whereas larger aggregates were formed. After 15 hours of interaction, none of the aggregates had a perimeter greater than 0.536 mm, consistent with an increase in aggregate compacting. These data demonstrate that elastin-cell interactions do not occur at random. These interactions may play a pivotal role in morphogenesis and in maintaining the integrity of elastic tissues such as the arterial wall, lungs, and skin.  相似文献   

8.
Nine white pigs weighing about 15 kg were divided into three groups: rapid expansion group (REG), conventional expansion group (CEG) and control group (CON). Expansion was carried out under monitoring of interal pressure of the expander and blood flow of the skin over the expander. After completion of expansion, hemodynamic, physical, histologic and ultrastructure changes of the expanded skin were measured and recorded. The study showed: (1) The immediate retraction ratios of skin of three groups were 41.37%, 20.82% and 10.01%, respectively (P < 0.01). (2) The thickness of the epidermis of the three groups was not statistically different, though the dermis of the expanded skin was thinner than that of the control (P < 0.01). (3) The density of collagen in the dermis of the three groups was 80.57 +/- 5.47, 79.49 +/- 6.31 and 82.72 +/- 2.69, respectively; the density of elastin of the three groups was 2.88 +/- 1.24, 2.77 +/- 0.74 and 2.56 +/- 0.63, respectively (P < 0.05). We concluded that the delay phenomenon of the expanded flap depends mainly on the intensity of expansion. The immediate retraction ratio of the rapidly expanded skin was greater than that of conventionally expanded skin. Rapid expansion also results in tissue hypertrophy but does not cause destruction of collagen. With proper calculating the size of the defect and estimating immediate skin retraction, rapid expansion is feasible in clinical applications.  相似文献   

9.
Chronically sun-exposed or photodamaged human skin is characterized by a number of clinical features, including wrinkles. However, little is known about the molecular mechanisms that underlie these features. We investigated the hypothesis that the mechanism of wrinkle formation may involve loss of anchoring fibrils, composed mainly of collagen VII, which are important in maintaining dermal-epidermal junction integrity. Ten volunteers with moderate to severe photodamage of dorsal forearm skin were recruited to the study. Using immunohistochemistry, transmission electron microscopy and in situ hybridization, we compared collagen VII protein and mRNA content of photodamaged forearm skin with that of sun-protected hip and upper inner arm skin from the same subjects. Numbers of anchoring fibrils per linear microns of basement membrane (mean +/- SEM) were significantly lower in photodamaged skin (1.79 +/- 0.10) as compared with sun-protected hip (2.28 +/- 0.11) and upper inner arm skin (2.21 +/- 0.10) (P < 0.01), and similarly keratinocyte expression of collagen VII mRNA, quantitated as number of positively stained keratinocytes per high power field, was significantly reduced in photodamaged skin (6.3 +/- 2.5) as compared with sun-protected hip (20.0 +/- 5.6) and upper inner arm skin (17.7 +/- 4.9) (P < 0.001). Semiquantitative assessment of immunohistochemical staining for collagen VII showed a non-significant reduction in photodamaged skin as compared with sun-protected skin. We propose that reduced content of collagen VII in photodamaged skin contributes to wrinkle formation by weakening the bond between the dermis and epidermis.  相似文献   

10.
Aging in the midface area is seen with ptosis of the malar tissues, hollowing of the infraorbital area, deepening of the nasolabial and mandibular labial folds, and increased jowling. Some of these aging changes are usually not corrected by a standard SMAS face lift. An endoscope-dependent technique was created specifically to address the midface area. The midface tissues are elevated and released in a subperiosteal manner and then suspended to a higher position after endoscopic dissection of the temporal area. The tissues are repositioned to a higher position on the malar area with softening of the nasolabial fold, decreased jowls, and recreation of the desired youthful fullness in the malar and infraorbital area. This procedure can be combined easily with other facial procedures such as rhytidectomy, neck lift, temple lift, and laser resurfacing when indicated. More than 200 procedures have been completed in the last 22 months. This report presents the surgical technique with early follow-up results.  相似文献   

11.
In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha1(I), alpha1(III) and transforming growth factor (TGF)-beta1 mRNA were investigated in six desmoid tumors; five derived from familial adenomatous polyposis patients and one from a sporadic case. The proportion of collagen production to total protein production was determined by 3H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC). The proportion of collagen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitatively, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro-alpha1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha1(III) collagen mRNA was more abundant in some of the desmoid tumors than the normal skin fibroblastic cell lines. Tumor growth factor-beta1 mRNA, which is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent. These results demonstrate the increased formation of collagen and elastin in desmoid tumors in vitro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta1 may be involved in increased fibrogenesis by desmoid tumors.  相似文献   

12.
PURPOSE: Quantify objectively the normative distribution and the percentage of smooth muscle fibers in the corpus cavernosum of human fetuses with 24 weeks post-conception (WPC) of gestational age. MATERIAL AND METHODS: We studied 7 penises taken from 7 fresh human fetuses. We analyzed 5 randomized sections from each penis and in every section we analyzed 3 fields, totaling 15 fields per penis and 105 fields for the final results. Immunohistological staining for the smooth muscle fibers was used to accentuate the differences between the intracavernous structures (smooth muscle fibers and collagen fibers). The fields studied were digitized with a final magnification of 450X and a computerized analysis of the smooth muscle fibers was performed with image analyzer software. The percentage of smooth muscle fibers per standard square area was estimated and the mean value was used for each penis. RESULTS: The distribution of smooth muscle fibers in the corpus cavernosum of human fetuses with 24 WPC of gestational age ranged from 17.52% to 27.76% of the total area. The mean value was 22.72% and the standard deviation was 3.56. CONCLUSIONS: Our results show that the percentage of smooth muscle cells in corpus cavernosum of human fetuses with 24 WPC of gestational age is significantly smaller when compared with the data available for adult cadavers.  相似文献   

13.
Hyperhomocysteinemia is a risk factor for arterial diseases, and the deterioration of the arterial elastic structures is one of the possible mechanisms underlying this epidemiological association. The aim of this paper is to quantitatively characterize such structural alterations and to explore their causes in a previous model of dietary induced mild hyperhomocysteinemia in minipigs. After four months, both a morphodensitometrical analysis of the elastic structure and a biochemical analysis of elastin and elastase activities were performed on the infrarenal abdominal aorta (IRAA) and the proximal left interventricular coronary artery (LIVCA) of control (C), hyperhomocysteinemic (H) and captopril-hydrochlorothiazide (Cp-Htz, 25 + 12.5 mg/d)-treated (H+/-Cp) minipigs (n = 8/group). Hyperhomocysteinemia was found to induce an increase in parietal elastolytic metalloproteinase activities. It resulted in opening and enlargement of fenestrae through the medial elastic laminae and in a decrease in medial elastin content (p < 10(-3)), expressed as well as volume density (%) as weight concentration (microg elastin/mg dry tissue). The thickness of the media and its basic lamellar organization was unchanged. The reduction in volume density was more dramatic in LIVCA (H: 4.7 +/- 0.9 vs C: 8.8 +/- 2.4), where it was evenly distributed within the media, than in IRAA (H: 6.7 +/- 1.1 vs C: 9.3 +/- 1.2), where the deep medial layers were less affected. Cp-Htz partly prevented the hyperhomocysteinemia-induced reduction of the medial elastin content in LIVCA (5.7 +/- 1.2) and IRAA (7.9 +/- 1.4). This effect, occurring in the subintimal layers of the media in both arteries but not in the deeper layers, resulted in a less beneficial effect in LIVCA than in IRAA. This result parallels the moderate beneficial therapeutic effect of ACE inhibitors against coronary atherosclerosis in humans. This paper reports for the first time a quantitative analysis of the arterial site-dependent deterioration of the elastic structure caused by mild hyperhomocysteinemia and the involvement of metalloproteinases in this process. These results confirm that the plaque-independent damage to elastic structure previously described in hyperhomocysteinemic-atherosclerotic minipigs was mainly due to homocysteine. This highlights that the metalloproteinase-related elastolysis and the subsequent structural deterioration is one of the major events underlying the epidemiological association between mild hyperhomocysteinemia and arterial diseases.  相似文献   

14.
OBJECTIVE: To investigate whether the thickness of the layers of the carotid artery (externa, media, and intima) are affected by menopause and its treatment with hormone replacement therapy (HRT). METHODS: One hundred twenty-nine postmenopausal women were recruited sequentially and classified into three groups. Forty-six were taking oral HRT, 32 had estradiol implants, and 51 had never taken HRT. The three layers of the externa wall of the carotid artery were identified and measured by high-resolution ultrasound. RESULTS: Women with implants had thicker carotid artery wall measurements (0.84 +/- 0.26 mm) than the other groups. The media (0.32 +/- 0.11 mm) was significantly thicker in the implant group. This layer has a high connective tissue component, including collagen type I, collagen type III, and elastin fibers. The intima layer was thinner (0.25 +/- 0.09 mm) in the oral HRT group compared with controls (0.29 +/- 0.1 mm). A statistically significant higher intima-media ratio (1.17 +/- 0.05) was calculated for the control group, compared with both the oral HRT (0.92 +/- 0.04) and implant groups (0.94 +/- 0.03). CONCLUSION: Our findings suggest that HRT given to postmenopausal women influences differentially the layers of the carotid artery. Hormones seem to encourage thickening of the layers with the highest connective tissue component (externa and media) and to delay thickening of the atheromatous intima layer. These effects on the vascular system may be partly responsible for the cardioprotection attributed to HRT.  相似文献   

15.
BACKGROUND: A quantitative study of dermal and arterial elastic fibers as a function of age was carried out by computerized image analysis. OBJECTIVE: We investigated whether any parallelism can be established between the morphometric parameters of elastic fibers from the skin and the temporal artery in elderly subjects. METHODS: we quantitated the skin elastic fibers of the reticular dermis and the elastic fibers of the temporal artery using a specific staining procedure followed by automated image analysis in 16 subjects of age range 63-87 years. RESULTS: There was a good correlation between the area fraction occupied by the elastic fibers in the unexposed skin (inner part of the upper arm) and aging (r = 0.669, p < 0.01). The area fraction occupied by elastic fibers in unexposed skin was correlated with the area fraction occupied by elastic fibers in the deep part of the temporal artery (r = 0.498, p < 0.05). Actinic elastosis affected both tissues, but there was no correlation between the amount of elastotic material in the exposed skin and the area fraction of elastic fibers in the superficial part of the temporal artery. CONCLUSION: We provided evidence that in sun-protected tissues the area fraction occupied by elastic fibers in dermis and deep part of the temporal artery showed a significant correlation. We proposed that skin biopsies were a valuable diagnostic tool for predicting arterial wall abnormalities of elastic fibers.  相似文献   

16.
The aim of this study was the histochemical, immunohistochemical and ultrastructural analysis of reparative fibrillogenesis in experimental lesions of Achilles' tendon. Subtotal tenotomy of Achilles' tendon was performed in twenty Wistar rats. The scar tissue was analysed 2, 4, 7, 14, 21, 30, 45 and 60 days post-operatively. Histochemical, (resorcin-fuchsin, aldehyde-fuchsin, iron haematoxylin and Fullmer and Lillie's methods) immunohistochemical (antibody against collagen I, II and elastin) and ultrastructural analyses were performed. Three phases in the healing process were distinguished: 1) inflammatory, 2) proliferative, and 3) remodelling phase. The inflammatory phase was characterised by haematoma, fibrin deposition, inflammatory cells, fibroblasts, beginning of collagen fibrillogenesis (200-400 A ? fibrils) and oxytalan fibrils. The proliferative phase was characterised by angiogenesis and fibroblast proliferation. Collagen fibres displayed a random arrangement and had a diameter of 400-600 A. Immature elastic fibres reached maximum tissutal concentration. In the remodelling phase, hypocellularity, normal vascularisation, tendon crimps, collagen fibres (800-1,000 A ?), elastic fibres with increased elastin deposition and reduction in oxytalan fibres were observed. In the course of the healing process collagen and elastic fibre fibrillogenesis exhibited consistent quantitative and qualitative variations (i.e. differences in the type and diameter of fibrils). The present study suggests that, together with other matrix macromolecules, also elastic fibres (oxytalan, elaunin and mature) are synthesised in significantly higher amounts during reparative fibrillogenesis and play a role in cell-matrix interaction.  相似文献   

17.
BACKGROUND: Clinical improvement in photodamaged skin after carbon dioxide (CO2) laser resurfacing is thought to result in part from thermal collagen shrinkage. The presence of such collagen has not been unequivocally demonstrated. To identify and characterize the morphological features of collagen after CO2 laser exposure, we irradiated ex vivo human facial skin and bovine calcaneus tendon with microsecond domain pulsed CO2 laser energy and examined specimens for histopathological and ultrastructural changes in collagen. OBSERVATIONS: In dermis and tendon, 3 zones of collagen structure were apparent on electron microscopy. The first, most superficial zone demonstrated loss of collagen structure. The second zone consisted of admixed normal collagen fibers and thickened collagen fibers. Zone 3 consisted of normal-appearing collagen fibers. CONCLUSIONS: Ultrastructural examination of irradiated collagen revealed distinct morphological zones of denatured collagen fibers. Partially denatured fibers had an increased diameter consistent with lineal shrinkage. Zonal distinction was undetectable by light microscopy. Ultrastructurally, the zones of denatured collagen located above the normal fibers correlated with the zone of altered material seen on light microscopy. These findings suggest that collagen fiber shrinkage does occur after pulsed CO2 laser irradiation and that this phenomenon contributed, at least in part, to the immediate tissue contraction observed clinically.  相似文献   

18.
OBJECTIVES: To evaluate the Rossavik growth model for predicting birth weight in a Dutch population and to evaluate growth cessation near term. STUDY DESIGN: Birth weight was predicted at various ages between 38 and 42 weeks, menstrual age (MA), and at birth age in 50 normal infants using two sets of ultrasound measurements obtained before 28 weeks, MA. Predicted birth weights were compared to actual weights. The mean percentage difference was used as a measure of systematic error and the standard deviation as a measure of random error. Linear regression analysis was used to evaluate the relationship between percentage differences and birth age. To evaluate the individual growth potential, the Growth Potential Realization Index for weight (GPRIWT) was determined for each fetus. RESULTS: The predictions at 39 and 39.15 weeks, MA, were accurate without systematic error and with a random error of +/-9.3%. Prediction at 38 weeks showed a statistical underestimation (mean +/- SD = -5.8% +/- 8.8), and statistical overestimations were found for predictions after 39.15 weeks and at birth age. A relationship between percentage differences and birth age was not found for predictions between 39.15 and 40 weeks, MA. These findings indicate that growth cessation occurred at 39.15 weeks, MA. Using birth weights predicted at 39.15 weeks, MA, GPRIWT were calculated. The mean GPRIWT value was not significantly different from 100% (p > 0.05), and individual GPRIWT values ranged from 84% to 114%. CONCLUSIONS: The Rossavik growth model can be used to predict birth weight in a Dutch population. However, growth cessation near term appears to occur later than previously reported in other populations.  相似文献   

19.
BACKGROUND: Plastic surgery literature reports the use of the superficial musculoaponeurotic system (SMAS) in reconstruction after parotidectomies to prevent the complications of Frey's Syndrome and fistula formation. However, there is scant information in the dermatologic literature regarding the use of the SMAS when closing Mohs defects overlying the parotid gland. OBJECTIVE: Our purpose is to introduce to the dermatologic surgery literature the need for plication of the SMAS prior to closure of the overlying tissues when repairing surgical defects which invade the integrity of the parotid gland. METHODS: We describe a patient with a large basal cell carcinoma located in the right preauricular region. Using text and photographs, we detail our closure of this large defect which invaded the parotid gland. RESULTS: Closure of the SMAS over the parotid gland before suturing the overlying tissues provided our patient with an excellent functional and cosmetic result, without the formation of a fistula, sialocele, or Frey's Syndrome. CONCLUSION: We propose that the essential first step in the ideal closure of surgical wounds which penetrate the parotid gland involves the isolation and plication of the SMAS. This will create a barrier to the accumulation of parotid secretions which, in turn, may lead to the development of a sialocele and fistula formation. Such a barrier will also prevent the formation of Frey's Syndrome. Furthermore, plication of the SMAS serves to improve cosmesis by contributing soft tissue bulk to the wound and avoiding a concave deformity.  相似文献   

20.
When burn injuries to the skin are extensive, delays in wound closure contribute to multiple organ failure because the availability of donor sites does not allow early and permanent coverage of excised wounds. From 1991 to 1996, 30 patients with a mean burn size of 78% total body surface area (65% full-thickness) underwent skin grafting with autologous cultured epidermis (AEC) performed in the labs of Genzyme Tissue Repair Company. Twenty three were adults and seven children under 15 (mean age 29, range 2.5 to 70); 27 suffered inhalation injury; 3 presented with multiple trauma and 2 with blast injury. As soon as possible wound beds were excised and temporarily covered with allografts or with sandwich or meshed autografts; the mean surface covered with autografts was 28 +/- 12%. Keratinocytes grafts were applied to a mean of 37 +/- 16.5%, an average of 210 grafts of 25 to 30 cm2. Three patients died respectively at day 67, 81 and 90. At time of gaze backing removal, the mean percentage of culture engraftment was 69% (range 25 to 95); this engraftment was higher for children (74%) and very bad above 60 (25%). The mean length of hospitalisation was 114 +/- 30 days. The definitive coverage by AEC was evaluated through the percentage of secondary autografted area: 10 +/- 9.5% (range 0 to 46). The average cost by patient was 98,500$ or 16$ by cm2 of culture. The weakness of epithelialisation makes essential a dermal support to the keratinocytes cultures, allodermis is now currently used, perhaps the new skin substitutes will give the ideal missing piece.  相似文献   

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