Histological evaluation of skin reconstruction using artificial dermis

In vitro evaluation of immunobiological activity of simple mannolipids

Immunomodulation, cytotoxicity and anti-cancer activity of selected amphiphilic non-ionic (thio)alkyl α-D-mannosides (with aglycone of C6-C12) were investigated in vitro in human cervix epitheloid carcinoma cell line HeLa, murine melanoma cancer cells B16, murine lymphocytic leukemia cell line L1210, murine fibroblast cell line NIH 3 T3 and murine macrophage cell line RAW 264.7. Toxicological studies revealed structure-dependent immunobiological effectivity based on a tight interaction with relevant cells. The results demonstrated diverse immunomodulation of macrophage cell-line RAW264.7 proliferation and production of Th1 and Th2 cytokines, and induction of pro-inflammatory interleukins IL-1α, TNFα, IL-6, IL-12 and IL-17 and anti-inflammatory IL-10 following (thio)alkyl α-D-mannosides 24 and 48 h exposure. Direct application of alkyl mannosides MOC10 and MOC12 and their thio analogues MSC10 and MSC12 in reconstructed human EpiDerm™ and MOC12 and MSC12 in EpiOcular™ model assays for dermal and ocular irritation together with quantification of human proinflammatory cytokines IL-1α, TNFα, IL-6 and IL-8 culture media release was used to ascertain toxicological safety.

Immunobiological efficacy and immunotoxicity of novel synthetically prepared fluoroquinolone ethyl 6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylate

The present study examined the cytotoxicity, anti-cancer reactivity, and immunomodulatory properties of new synthetically prepared fluoroquinolone derivative 6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylate (6FN) in vitro. The cytotoxicity/toxicity studies (concentrations in the range 1-100μM) are focused on the cervical cancer cells HeLa, murine melanoma cancer cells B16, non-cancer fibroblast NIH-3T3 cells and reconstructed human epidermis tissues EpiDerm™. The significant growth inhibition of cancer cells HeLa and B16 was detected. The cytotoxicity was mediated via apoptosis-associated with activation of caspase-9 and -3. After 72h of treatment, the two highest 6FN concentrations (100 and 50μM) induced toxic effect on epidermis tissue EpiDerm™, even the structural changes in tissue were observed with concentration of 100μM. The effective induction of RAW 264.7 macrophages cell-release of pro- and anti-inflammatory T_H1, T_H2 and T_H17 cytokines, with anti-cancer and/or anti-infection activities, respectively, has been revealed even following low-dose exposition.

Collagen Hydrogel Scaffold and Fibroblast Growth Factor-2 Accelerate Periodontal Healing of Class II Furcation Defects in Dog

OBJECTIVE

Collagen hydrogel scaffold exhibits bio-safe properties and facilitates periodontal wound healing. However, regenerated tissue volume is insufficient. Fibroblast growth factor-2 (FGF2) up-regulates cell behaviors and subsequent wound healing. We evaluated whether periodontal wound healing is promoted by application of collagen hydrogel scaffold in combination with FGF2 in furcation defects in beagle dogs.

METHODS

Collagen hydrogel was fabricated from bovine type I collagen with an ascorbate-copper ion cross-linking system. Collagen hydrogel was mingled with FGF2 and injected into sponge-form collagen. Subsequently, FGF2 (50 µg)/collagen hydrogel scaffold and collagen hydrogel scaffold alone were implanted into class II furcation defects in dogs. In addition, no implantation was performed as a control. Histometric parameters were assessed at 10 days and 4 weeks after surgery.

RESULT

FGF2 application to scaffold promoted considerable cell and tissue ingrowth containing numerous cells and blood vessel-like structure at day 10. At 4 weeks, reconstruction of alveolar bone was stimulated by implantation of scaffold loaded with FGF2. Furthermore, periodontal attachment, consisting of cementum-like tissue, periodontal ligament-like tissue and Sharpey's fibers, was also repaired, indicating that FGF2-loaded scaffold guided self-assembly and then re-established the function of periodontal organs. Aberrant healing, such as ankylosis and root resorption, was not observed.

CONCLUSION

FGF2-loaded collagen hydrogel scaffold possessed excellent biocompatibility and strongly promoted periodontal tissue engineering, including periodontal attachment re-organization.

Atelocollagen Sponge and Recombinant Basic Fibroblast Growth Factor Combination Therapy for Resistant Wounds with Deep Cavities

Recent advances in bioengineering have introduced materials that enhance wound healing. Even with such new tools, some deep ulcers surrounded by avascular tissues, including bone, tendon, and fascia, are resistant to various therapies and easily form deep cavities with loss of subcutaneous tissue. Atelocollagen sponges have been used as an artificial dermis to cover full-thickness skin defects. Topical recombinant human basic fibroblast growth factor has been introduced as a growth factor to induce fibroblast proliferation in skin ulcers. We applied these materials in combination in two patients with deep resistant wounds: one with a cavity reaching the mediastinum through a divided sternum and one with deep necrotic wounds caused by electric burns. These wounds did not respond to the topical basic fibroblast growth factor alone. In contrast, the combination therapy closed the wounds rapidly without further surgical treatment. This combination therapy is a potent treatment for resistant wounds with deep cavities.

Evaluation of EpiDerm full thickness-300 (EFT-300) as an in vitro model for skin irritation: studies on aliphatic hydrocarbons

The aim of this study was to understand the skin irritation effects of saturated aliphatic hydrocarbons (HCs), C9-C16, found jet fuels using in vitro 3-dimensional EpiDerm full thickness-300 (EFT-300) skin cultures. The EFT-300 cultures were treated with 2.5microl of HCs and the culture medium and skin samples were collected at 24 and 48h to measure the release of various inflammatory biomarkers (IL-1alpha, IL-6 and IL-8). To validate the in vitro results, in vivo skin irritation studies were carried out in hairless rats by measuring trans epidermal water loss (TEWL) and erythema following un-occlusive dermal exposure of HCs for 72h. The MTT tissue viability assay results with the EFT-300 tissue show that 2.5microl/tissue ( approximately 4.1microl/cm(2)) of the HCs did not induce any significant changes in the tissue viability for exposure times up to 48h of exposure. Microscopic observation of the EFT-300 cross-sections indicated that there were no obvious changes in the tissue morphology of the samples at 24h, but after 48h of exposure, tridecane, tetradecane and hexadecane produced a slight thickening and disruption of stratum corneum. Dermal exposures of C12-C16 HCs for 24h significantly increased the expression of IL-1alpha in the skin as well as in the culture medium. Similarly, dermal exposure of all HCs for 24h significantly increased the expression of interleukin-6 (IL-6) and IL-8 in the skin as well as in the culture medium in proportion to the HC chain length. As the exposure time increased to 48h, IL-6 concentrations increased 2-fold compared to the IL-6 values at 24h. The in vivo skin irritation data also showed that both TEWL and erythema scores increased with increased HCs chain length (C9-C16). In conclusion, the EFT-300 showed that the skin irritation profile of HCs was in the order of C9C10C11C12<C13 approximately C14 approximately C16 and that the tissue was an excellent in vitro model to predict in vivo irritation and to understand the structural activity relationship of HCs.

Bioimaging assessment and effect of skin wound healing using bone-marrow-derived mesenchymal stromal cells with the artificial dermis in diabetic rats

We investigate the relationship between the fate and healing effect of transplanted mesenchymal stromal cells (MSCs) in a rat diabetic skin wound model. Rats are treated with streptozotocin to induce diabetic conditions. A full-thickness skin defect is surgically made on the head of diabetic rats, and covered with an artificial dermis impregnated with either bone marrow cells (BMCs) or bone-marrow-derived MSCs from firefly luciferase (luc) transgenic (Tg) rats. Wound healing is evaluated using planimetry and immunohistochemistry, and the fate of transplanted MSCs is determined using in-vivo luminescent imaging. The diabetic wound treated with MSCs-impregnated artificial dermis is significantly smaller than that treated with artificial dermis alone at 1 week postoperation. Photons of luc+ MSCs are detected at the transplanted site during healing (3 weeks), whereas those of luc+ MSCs are depleted only after 1 week postimplantation. Immunohistochemistry at the healing site treated with MSCs demonstrates that CD31+ vessels increase with expression of vascular endothelial growth factor, suggesting that MSCs accelerate angiogenesis. These findings suggest that transplanted MSCs could be retained at wound sites during the healing process in a diabetic rat model, and subsequently promote wound healing through angiogenesis.

The use of artificial dermis for surgical defects in the treatment of oral premalignant lesions

BACKGROUND

This study investigated the application of an artificial dermis as a substitute for split-thickness skin graft in an oral mucosal defect after excision of a premalignant lesion.

METHODS

We examined a total of 125 sites repaired with artificial dermis in 84 patients. Forty-one of 84 patients had two different defects and 43 had a single defect. Of 84 patients, there were 52 oral leukoplakia and 32 oral submucous fibrosis.

RESULTS

Most patients chewed betel nuts (97.6%). Most of the premalignant lesions were located in the buccal mucosa (94%). The overall success rate was 100% without any or partial graft loss. The minor wound oozing occurred in three grafts (2.4%). No patient had an immunologic reaction or experienced with significant pain.

CONCLUSIONS

Therefore, an artificial dermis may be an alterative to a split-thickness skin graft for patients with oral mucosal defects after removal of premalignant lesions.

Wound healing effect of acellular artificial dermis containing extracellular matrix secreted by human skin fibroblasts

In this study, an acellular artificial dermis, composed of human collagen and glycosaminoglycan (GAG) secreted by cultured human fibroblasts on a bovine collagen sponge, was developed. Much of the newly secreted extracellular matrix (ECM) remained after the cell removal process. The main theme of this study focused on the matrix, rather than the viable cell components of the skin, as the major dermal deficit in the wound. Both the acellular artificial and bioartificial dermises, containing viable cells with ECM, were significantly less soluble than the collagen sponge, and the relative GAG content in the bioartificial and acellular artificial dermises was approximately 115-120% of the chondroitin-6-sulfate (CS) content found in the collagen sponge. In the group receiving the collagen sponge, the wound area gradually decreased to approximately 10% of its original area, while in the groups receiving the bioartificial and acellular artificial dermises, the wound area also gradually decreased to approximately 60 and 50%, respectively, of the original size over the 5 weeks after grafting. Both the bioartificial and acellular artificial dermises formed thicker, denser collagen fibers; more new blood vessel formation was observed in both cases. The basement membrane of the regenerated epidermal-dermal junction was thicker and more linear in the acellular artificial dermis graft than in the collagen sponge graft. In conclusion, the wound healing effects of acellular artificial dermis are no less than those of the bioartificial dermis, and much better than the collagen sponge graft with respect to wound contraction, angiogenesis, collagen formation, and basement membrane repair.

Basic fibroblast growth factor in an artificial dermis promotes apoptosis and inhibits expression of ?-smooth muscle actin, leading to reduction of wound contraction

To clarify the mechanisms underlying declines in wound contraction caused by basic fibroblast growth factor (bFGF) and the role of autologous fibroblasts in modulating wound healing, we have examined the expression of alpha-smooth muscle actin (alpha-SMA) and apoptosis in a model of wound healing using collagen sponges with and without bFGF (1 microg) and/or fibroblasts (1 x 10(6) cells/cm(2)) applied to experimentally produced full-thickness skin wounds in rats (n=10 for each group). At 7 days postoperatively, wounds filled with a fibroblast-seeded collagen sponge (fibroblast-seeded group) displayed a greater area of collagen sponge and a smaller area of fibroblasts compared with control wounds filled with collagen sponge alone (control group). Therefore, seeding of fibroblasts in the dermal substitute might retard degradation of the collagen sponge, inhibiting fibroblast infiltration into the substitute. By day 14, wounds filled with bFGF-treated collagen sponge without fibroblast seeding (bFGF group) displayed decreased alpha-SMA expression and significantly increased apoptosis compared with other wounds. Double staining revealed that apoptosis in alpha-SMA-positive fibroblastic cells was significantly increased in the bFGF group, suggesting that bFGF treatment is a potent stimulator of myofibroblast apoptosis. Furthermore, morphometric analysis demonstrated the significant decrease in the level of wound contraction and the degree of mature collagen bundle formation in the bFGF group by day 42. The bFGF group also showed increased bFGF expression in macrophages by day 28. These results suggest that bFGF administration to an artificial dermis promotes apoptosis of alpha-SMA-positive fibroblastic cells and inhibits alpha-SMA expression in the treated wound, thus reducing wound contraction.

In vitro and in vivo comparison of dermal irritancy of jet fuel exposure using EpiDerm (EPI-200) cultured human skin and hairless rats

The purpose of this study was to evaluate an in vitro EpiDerm human skin model (EPI-200) to study the irritation potential of jet fuels (JP-8 and JP-8+100). Parallel in vivo studies on hairless rats on the dermal irritancy of jet fuels were also conducted. Cytokines are an important part of an irritation and inflammatory cascade, which are expressed in upon dermal exposures of irritant chemicals even when there are no obvious visible marks of irritation on the skin. We have chosen two primary cytokines (IL-1alpha and TNF-1alpha) as markers of irritation response of jet fuels. Initially, the EPI-200 was treated with different quantities of JP-8 and JP-8+100 to determine quantities which did not cause significant cytotoxicity, as monitored using the MTT assay and paraffin embedded histological cross-sections. Volumes of 2.5-50 microl/tissue (approximately 4.0-78 microl/cm2) of JP-8 and JP-8+100 showed a dose dependent loss of tissue viability and morphological alterations of the tissue. At a quantity of 1.25 microl/tissue (approximately 2.0 microl/cm2), no significant change in tissue viability or morphology was observed for exposure time extending to 48 h. Nonetheless, this dose induced significant increase in IL-1alpha and TNF-alpha release versus non-treated controls after 24 and 48 h. In addition, IL-1alpha release for JP-8+100 was significantly higher than that observed for JP-8, but TNF-alpha release after 48 h exposure to these two jet fuels was the same. These findings parallel in vivo studies on hairless rats, which indicated higher irritation levels due to JP-8+100 versus JP-8. In vivo, transepidermal water loss (TEWL) and IL-1alpha expression levels followed the order JP-8+100 > JP-8 > control. Further, in vivo TNF-alpha levels for JP-8 and JP-8+100 were also elevated but not significantly different from one another. In aggregate, these findings indicate that EPI-200 tissue model can be utilized as an alternative to the use of animals in evaluating dermal irritation.

Effect of methyl substitution of benzene on the percutaneous absorption and skin irritation in hairless rats

The permeation rate and skin retention of benzene and methylbenzenes were assessed in vitro using hairless rat skin. The effects of unocclusive dermal exposures of these chemicals (15 microl every 2h for 8h a day for 4 days) on the transepidermal water loss (TEWL), erythema and skin histopathology were measured in CD hairless rats. The expression of IL-1 alpha and TNF-alpha in the skin and blood were measured at the end of dermal exposures. The flux of benzene was about 1.5-, 2.5- and 80-fold higher than toluene, xylene and tetramethyl benzene isomers (TMB), respectively, and the values were inversely correlated with molecular weight (r(2)=0.7455) and logoctanol-water partition coefficient (r(2)=0.7831). The retention of chemicals in stratum corneum (SC) was in the order of TMB>xylene>toluene approximately benzene. The TEWL and erythema data demonstrated that the irritation was in the following order: TMB>xylene>benzene. The histo-pathological examination showed that xylene and TMB induced granulocyte infiltration, swelling of the epidermis, and extensive disruption and damage of stratum corneum. Likewise, the expression of IL-1 alpha in the blood and TNF-alpha in the skin after dermal exposures was higher for TMB followed by xylene and benzene compared to control. In conclusion, the aromatic hydrocarbon chemicals induced cumulative irritation upon low-level repeat exposures for a 4-day period and the irritation increased with the number of methyl groups of benzene. The affinity of the chemical to SC and their gradual accumulation in the skin in the present study is the reason for the differences in the skin irritation profiles of different aromatic chemicals. Our ultimate goal is to develop a biologically based model that connects skin retention of chemical to the skin irritation response. The findings of the present study will be helpful in understanding the role of these chemicals in the jet fuel and various petroleum based fuels in inducing skin irritation response.

Bone marrow-impregnated collagen matrix for wound healing: experimental evaluation in a microcirculatory model of angiogenesis, and clinical experience

OBJECTIVES

This study aims to investigate the effect of collagen matrix impregnated with bone marrow on wound healing angiogenesis in an effective microcirculatory model and to describe our clinical experience.

METHODS

We used a skinfold chamber of original design which visualises microcirculation following wound creation on the dorsal skin of the mouse to establish an in vivo experimental model to estimate angiogenesis. Animals were divided into two groups: a bone marrow group (n = 6) in which bone marrow-impregnated collagen matrix was applied to the wound; and a control group (n = 7), in which collagen immersed in saline was applied, and functional capillary density was quantified during the repair process.

RESULTS

The increase rate in functional capillary density during wound healing significantly increased in the bone marrow group on days 3, 5 and 7 after creation of the wound but no significant difference was detected on day 10. A patient with a chronic leg ulcer that had not responded to conventional therapy for 1 year was treated with autogenous bone marrow-impregnated collagen matrix and successful wound closure was obtained.

CONCLUSION

The present study suggested that collagen matrix impregnated with bone marrow significantly promoted the repair process, especially in the early stage. The features of the treatment, including the possible use of a patient's own cells, simple method, immediate application without any processing procedure and preservation of the inclusive potentiality of bone marrow suspension, offer significant advantages in terms of the anticipated routine clinical use.

Clinical evaluation of a new bilayer artificial dermis for repair of oral mucosal defects: report of two cases

Free mucosal grafts or split-thickness skin grafts have been used in patients undergoing repair procedures for oral mucosal defects. Conventional methods require the creation of second surgical wounds for use as donor sites. We applied two bilayers of artificial dermis to repair a buccal mucosal defect in one case and vestibular extension in another case. After removal of the sutures, no infection, pain, or hemorrhage developed in these patients. The results of granulation and epithelialization were good. Satisfactory appearance and function were achieved in both cases. Therefore, bilayer artificial dermis may be recommended for the repair of oral mucosal defects.

A method for correcting an inverted nipple with an artificial dermis

Various methods have been reported to correct an inverted nipple. Although a satisfactory outcome has been reported with most techniques, each method carries a drawback inherent in the technique itself, including complicated operative technique, sensory disturbance of the nipple, marked scarring of the nipple areola and other donor regions, destruction of breast function, and incomplete correction. This report describes a simple method for correcting an inverted nipple. It incorporates a new concept of using artificial dermis for tissue augmentation and is performed without sacrificing any donor site and complex design. It was applied to four nipples in two nulliparous cases. For all four corrected inverted nipples, good results were obtained, and there have been no complications. There were no deformities of the nipples or the areolas after this procedure, and the surgical scars were inconspicuous.

Regenerative Surgery for Sacral Pressure Ulcers Using Collagen Matrix Substitute Dermis (Artificial Dermis)

Collagen matrix substitute dermis, or artificial dermis, has recently been developed to induce angiogenesis and fibroplasia in deep, poorly vascularized tissue defects, and its use is desirable as a means of achieving effective treatment with less invasion. However, it is difficult to apply collagen matrix to pressure ulcers, because they are usually accompanied by infection with discharge of excessive amounts of exudate or pus and generally exposed to external forces that prevent graft fixation. To overcome these difficulties, the authors demonstrated a novel procedure to exclude unfavorable exudate and external forces. The procedure resulted in successful fixation of the artificial dermis and induction of regeneration in poorly vascularized defects in every case. The histologic findings provided supporting evidence that collagen matrix acts as a scaffold for reconstruction of nearly normal vascular structures coursing perpendicularly in the upper layer of normal dermis.

Mucosal reconstruction using an artificial dermis after KTP laser surgery

OBJECTIVE

The aim of the present study is to assess the clinical effectiveness of the artificial dermis.

BACKGROUND DATA

We have previously observed prolonged postoperative pain and bleeding in patients receiving potassium titanyl phosphate (KTP) laser surgery for oral mucosal diseases.

MATERIALS AND METHODS

The artificial dermis was placed on the wound and fixed to the surrounding oral mucosa by silk suturing. The silicon sheet of the artificial dermis and the sutures were removed on the seventh postoperative day. Postoperative bleeding from the oral mucosa, duration of postoperative pain, and the period required for healing were all assessed clinically. The results were compared to those in a group of similar cases which were treated without the artificial dermis. In this retrospective review, we considered 20 cases of tongue lesion treated by KTP laser (10 leukoplakias, nine squamous cell carcinomas, and one metastatic renal cell carcinoma to the tongue), nine of which were followed by application of an artificial dermis to prevent postoperative pain and bleeding, and 11 of which were not.

RESULTS

No postoperative bleeding was observed in the group of cases treated with an artificial dermis, although it was observed in 45.5% in the group of cases treated without an artificial dermis. There was a statistical difference between these two groups (p < 0.03).

CONCLUSION

It was concluded that use of artificial dermis prevented postoperative bleeding.

Effects of collagen matrix containing transforming growth factor (TGF)-beta(1) on wound contraction

We evaluated the effectiveness of transforming growth factor (TGF)-beta(1) on wound contraction, both alone and in combination with collagen matrix, using an in vivo delayed wound healing type model. To clarify the mechanisms involved in the effectiveness of TGF-beta(1), we also used a fibroblast-populated collagen gel contraction in vitro model. Although we found that TGF-beta(1) significantly accelerated contraction of the fibroblast-populated collagen gel in vitro, we demonstrated that both collagen matrix alone and 1.0 microg of TGF-beta(1) alone significantly inhibited wound contraction in the in vivo model. In addition, the combination of TGF-beta(1) and collagen matrix was much more effective than TGF-beta(1) alone, a finding which was supported by histopathological examination. Wounds treated with collagen matrix containing TGF-beta(1) showed horizontal rearrangement of collagen fibers in the dermal part as well as evidence of active fibroblast proliferation, which was not observed in the scar regions of controls. These results show that the application of TGF-beta(1) treated collagen matrix is effective for preventing contraction producing so called "neodermis" in treating a delayed healing type model and may be highly beneficial for treating chronic wounds.

Analysis of the vascularity of an atelocollagen sponge substitute dermis in the human

Atelocollagen sponge had been developed as a new beneficial dermal substitute. However, histologic studies of the vascularity of an atelocollagen sponge substitute dermis in humans are very rare. The purpose of this study was to determine the distribution of blood vessels in an artificial dermis made of atelocollagen affixed to human tissue. The artificial dermis was used in 21 cases and at 23 sites, and biopsies were performed. The samples were stained with anti-human blood type A, B, and H monoclonal antibodies. Angiogenesis in the upper layer of the artificial dermis was recognizable within 14 days after affixing the artificial dermis. We concluded that a skin graft taken 14 days after affixing the artificial dermis would be successful, even though the granulation tissue formation might not be completed and the color would most likely remain white. The lower layer of the angiogenesis spread in a horizontal direction like an expanded network of blood vessels, while the middle and upper layers of angiogenesis spread perpendicularly to form upward growth when two cases were examined in various spots. The data suggested that the sponge construction of artificial dermis not only became a scaffold for the invasion of collagen, but it also facilitated construction of near normal dermis with regard to the construction of blood vessels.

Effects of a collagen matrix containing prostaglandin E(1) on wound contraction

In this study, we evaluated the effectiveness of prostaglandin (PG) E(1) in inhibiting wound contraction, both alone and in combination with collagen matrix, using a in vivo full thickness skin defect model. To clarify the mechanisms involved in this inhibition we also used a fibroblast-populated collagen gel contraction in vitro model. We demonstrated that collagen matrix alone significantly inhibited wound contraction PG E(1) alone did not. Interestingly, their combination was much more effective than either collagen matrix or PG E(1) alone, a finding which was also supported by histopathological examination. Wounds treated with collagen matrix, but not control wounds, showed horizontal rearrangement of collagen fibers in the dermal part as well as evidence of active fibroblast proliferation which was not observed in scar regions surrounded by normal dermis. With the fibroblast-populated collagen gel contraction in vitro model, we found that PG E(1) significantly inhibited contraction at a high dose. It was concluded that collagen matrix combined with PG E(1) is effective for preventing contracture producing so called neodermis than collagen matrix alone, which remains one of the most challenging problems in treating full thickness type wounds.

Articulatory function in patients who have undergone glossectomy with use of an artificial graft membrane

OBJECTIVE

The purpose of this study was to investigate, by assessing speech intelligibility, the long-term usefulness of an artificial bilayer membrane as a mucosal substitute after glossectomy.

STUDY DESIGN

Artificial membranes were grafted in 8 patients with intraoral defects after glossectomy. Five patients served as a control group and received only standard closure by suture after glossectomy. Speech intelligibility was evaluated by means of a standardized Japanese speech intelligibility test 6 months or more after the operation.

RESULTS

The postoperative courses of all 13 patients were uneventful. Intelligibility scores of those who received grafts were better than those of the control group in the overall score, the glossal sounds score, and the rear portion sounds score.

CONCLUSION

The artificial membrane was useful for the glossectomy as a long-term mucosal substitute, as well as for the short-term.

Effects of a collagen matrix containing basic fibroblast growth factor on wound contraction

We evaluated the effectiveness of basic fibroblast growth factor (bFGF) in inhibiting wound contraction, both alone and in combination with collagen matrix, using a simulated in vivo delayed healing type model. We also studied the mechanisms involved in this inhibition in in vitro experiments using fibroblast populated collagen gels. As a result, we were able to demonstrate that both collagen matrix and bFGF significantly inhibited wound contraction; especially, bFGF acted in a dose-dependent fashion. Interestingly, their combination was much more effective than either collagen matrix or bFGF alone, a finding that was supported by the histopathological data. Wounds treated with collagen matrix, but not control wounds, showed horizontal rearrangement of collagen fibers in dermis as well as evidence of fibroblast proliferation, which was not observed in scar regions surrounded by normal dermis. Using fibroblast-populated collagen gel contraction as an in vitro model, we found that bFGF significantly inhibited contraction. Taking all these results together, it was concluded that collagen matrix is useful not only as a carrier of cytokines such as bFGF, but also for the quick closure of chronic wounds, thereby preventing contracture, which remains one of the most challenging problems in treating this type of wound. Application of bFGF-treated collagen matrix to chronic wounds such as decubitus, and diabetic and leg ulcers may prove to be highly beneficial in clinical practice.

The use of a new bilayer artificial dermis for vestibular extension

In this study we evaluated the usefulness of a new bilayer artificial dermis (TERUDERMIS; Terumo Corporation, Japan) for vestibular extension. It is composed of a collagen sponge with the silicone layer which is sloughed off as the mucous membrane heals. We have used it for vestibular extension in 50 patients. The material was effective in nearly all patients in promoting haemostasis, relieving pain, inducing granulation, promoting rapid epithelialization, and preventing contracture. There were no side-effects. The greatest problem with such materials in the past has been contracture at the vestibular extension area. However, we found that the degree of contracture was similar to that seen with autogenous mucosa or free skin graft. Our results indicate that the material might be useful for vestibular extension.