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H Bannasch

Publications and source records attributed to H Bannasch.

13 recordsLinked to original sources
PubMed2003

[Skin tissue engineering].

Cultivated epithelial autografts as multilayered, thin sheets represent a common standard in clinically applied tissue engineering substitutes, outnumbering all experimental alternatives. However, the unsatisfying short- and long-term results concerning mechanical stability and scarring require alternatives. The cultivation and transplantation of cultured autologous keratinocytes as a single cell suspension in a fibrin matrix, combined with allogenic skin grafting, has been investigated extensively in athymic nude mice. Wounds can be reliably reepithelialized after a cultivation period of only 14 days. Moreover, the successful combination of keratinocyte fibrin suspension and acellular dermis in an attempt to regenerate full thickness skin defects in a pig model has been demonstrated. The usefulness of subconfluently cultured keratinocytes-which can be harvested very early and are easy to handle-is enhanced by cotransplantation with decellularized dermis.

Animals↗
PubMed2003

Skin tissue engineering.

The coverage of extensive wounds with viable autologous keratinocytes remains the only option of treatment if autologous donor skin is not obtainable. There is evidence that proliferating keratinocytes, as suspended cells or as a single layer, are adequate for wound closure. Understanding keratinocyte-matrix interactions not only allows us to influence keratinocyte outgrowth, adhesion, and migration, but may also guide us to modify matrix molecules for enhancing keratinocyte take. Further approaches may include the generation of genetically manipulated keratinocytes, which allow the use of an off-the-shelf epidermal replacement. As surgeons, our goal is to help burn patients with the best quality of skin in the shortest time possible. As tissue engineers, we have not achieved the goal of a universal skin product. By continually reviewing the options and using them, we can at least use the proper material in the adequate situation. Because of the limited resources, the need for comparisons of clinical effectiveness and cost are ever more important. As anatomy and physiology of engineered skin substitutes improve, they will become more similar to native skin autografts. Improvement of skin substitutes will result from inclusion of additional cell types (eg, melanocytes) and from modifications of culture media and scaffolds. Skin-substitute materials may be able to stimulate regeneration rather than repair, and tissue-engineered skin may match the quality of split-skin autografts, our present gold standard.

Animals↗
PubMed2003

Engineering of muscle tissue.

The loss or failure of an organ or tissue is one of the most frequent, devastating, and costly problems in health care. Tissue engineering and regenerative medicine is an emerging interdisciplinary field that applies the principles of biology and engineering to the development of viable substitutes that restore, maintain, or improve the function of human tissues and organs. Tissue engineering science has provided critical new knowledge that will deepen our understanding of the phenotype of an important category of cell types-the muscle cells-and this knowledge may enable meaningful advances in musculoskeletal tissue engineering. There are two principle strategies for the replacement of impaired muscle tissues. One approach uses the application of isolated and differentiated cells (in vivo tissue engineering), using a transport matrix for the cell delivery; the other uses in vitro-designed and pre-fabricated tissue equivalents (in vitro tissue engineering). Future developments and the decision regarding which approach is more promising depend on the elucidation of the relationships among cell growth and differentiation, the three-dimensional environment, the architecture of the cells, and gene expression of the developmental process and the survival of the cells and integration in the host in in vivo experiments. As the techniques of tissue engineering become more sophisticated and as issues such as vascularization and innervation are addressed, the usefulness of these methods for reconstructive surgery may grow significantly.

Humans↗
PubMed2001

[Minimally invasive surgical therapy of gynecomastia: liposuction and exeresis technique].

INTRODUCTION: A number of techniques are available for the correction of gynecomastia. Nonscarring sparing methods are preferred, and the minimally invasive technique is to use liposuction for the gland and the fatty tissue exclusively. In this retrospective study we present our experience with a combination of liposuction and subsequent resection of the remaining gland. METHODS: Sixty-two patients (112 breasts) were surgically treated for gynecomastia from January 1996 and September 2000. From 1996 to 1997 all patients suffering from gynecomastia grade Simon I-II were treated by the method described by Rosenberg and Stark, which is exclusively suction of the fatty and glandular tissue. In a retrospective chart study a high recurrence rate was found in these patients. Subsequently we changed our technique to liposuction of the fatty tissue followed by sharp excision of the glandular tissue through the incision made for the liposuction cannula in the submammary fold. RESULTS: Suction alone was not sufficient to remove the glandular tissue; the rate of recurrence after suction was 35%. When sharp resection of the glandular tissue was carried out after the liposuction the recurrence rate dropped to under 10%. In total our complication rate was 50% including minor sequelae. The most frequent complication was unacceptable scarring of the nipple-areola complex. Hypesthesia of the nipple-areola occurred in 13.4% of the patients. CONCLUSION: The combination of liposuction and resection of the glandular tissue is a minimally invasive correction that can be used in all cases of gynecomastia grade Simon I-II.

Adult↗
PubMed2001

Fibrin glue as matrix for cultured autologous urothelial cells in urethral reconstruction.

In the present study, we have established a technique to create an artificial urethra in a rat animal model by transplantation of in vitro-expanded urothelial cells onto an in vivo-prefabricated tube formation using tissue engineering methods. Urothelial cells from isogenic rats were harvested for culture. A silicon catheter was used to induce a connective tissue capsule-tube formation underneath the abdominal skin. Two weeks later, the cultivated urothelial cells were seeded onto the lumen of this tube using fibrin glue as delivery matrix. The histomorphological and immunohistochemical studies revealed a viable multilayered urothelium, lining the inner surface of the prior formed connective tissue tube-formation 4 weeks after grafting the cells. We have shown that cultured and in vitro-expanded urothelial cells can be successfully reimplanted onto a prefabricated tube-like structure using fibrin glue as a delivery matrix and native cell expansion vehicle. The results suggest that the creation of an artificial urethra may be achieved in vivo using tissue engineering methods, showing potential for urethral reconstruction and providing autologous urothelium for reconstructive surgery in the genitourinary tract.

Animals↗
PubMed2000

[Cell transplantation in surgery--reality and prospects for tissue engineering].

Traditionally surgical repair of tissue defects and loss or failure of function has relied on mechanical means, medical (drug) treatment, autologous and allogenic transplantation, and alloplastic/synthetic devices. Tissue engineering represents a new interdisciplinary field of applied research combining engineering and biosciences together with clinical application (mainly in surgical specialities) to develop living substitutes for tissues and organs. The understanding of cell-cell interactions and chemical signalling (growth factors) and the selection of appropriate matrices (cell-matrix interaction) is the key for success. Gene therapy represents the logical combination with tissue engineering on the molecular biology level. Application of cultivated skin and cartilage has already become reality, engineering of vascularized, more complex organs remains a challenge for this century.

Cells, Cultured↗
PubMed2000

[Tissue engineering: possibilities and perspectives].

Successful tissue engineering requires intensive co-oporation between clinicians, biologists (cell culture, gene therapy), chemical engineers (biomaterials) and industrial partners. In case of wound healing tissue engineered constructs have already been applied successfully in burns and chronic wounds. In order to improve carrier and matrix function biomaterials still have to be optimized. The potential of such constructs might even be enhanced by gene therapeutical methods. The complex mammalian organism has to be considered as the gold standard and the model for perfect tissue engineering. The problem of vascularization of complex organs yet has to be solved. In general it seems to be more promising to substitute deficient components in vivo and to rely on modulating influences within the host organism rather than to create complex organs ex vivo.

Animals↗
PubMed2000

[Gene therapy perspectives in modulation of wound healing].

A variety of reasons can afflict wound healing. Current research is focussed on the acceleration of wound healing by stimulating molecular processes. Gene therapy may offer completely new ways to treat chronic wounds. Possible advantages of gene therapeutic modulation of wound healing might be a long term efficiency, systemic or local regulation of gene expression and low side-effects. Current goals comprise the improvement of transfection efficiency and specificity. In vivo applications are therefore focussed on optimized inducible or even cell-type specific promotors, as well as on improved local application techniques. Studies from our laboratory demonstrate the possibility to combine modern cell culture techniques with different types of gene transfer. This enables the simultaneous grafting of manipulated cells to the wound with the continuous delivery of specific proteins of interest. Experimentally, this lead to accelerated closure of partial and full thickness animal wounds. Clinically, gene therapy for the treatment of chronic wounds seems to be a realistic goal within the next years and might be applicable for a variety of novel indications.

Animals↗
PubMed2000

[Treatment of chronic wounds with cultured autologous keratinocytes as suspension in fibrin glue].

Cultivated keratinocytes have been used for treatment of chronic wounds. Our group developed a new application form, using a suspension of subconfluently cultivated keratinocytes in fibrin glue (keratinocyte-fibrin-glue-suspension = KFGS), which has successfully been used in burn patients. Altogether 8 patients (average: 57 yrs.) with complex chronic wounds of different origin were treated with KFGS. All wounds, which had been existing from 4 months to 14 years, showed good reepithelization. Up to now there has been observed stable wound closure for 4 years after grafting. This study demonstrates the wound healing potency of a keratinocyte-fibrin-glue-suspension also for chronic wounds. Fibrin glue seems to be both an ideal application vehicle as a biological matrix for the cultivated keratinocytes. The transplantation of cultivated autologous keratinocytes as suspension in fibrin glue is a promising way in the treatment of chronic wounds.

Adult↗
PubMed1999

[Keratinocyte transplantation and tissue engineering. New approaches in treatment of chronic wounds].

Cultured keratinocytes have been used for the treatment of extensive burns since disease lethality is reduced. Consequently, the treatment of chronic wounds with keratinocytes may be promising. Cell culture technology allows to expand keratinocytes up to 6000-fold in vitro after taking a single biopsy from patient. Today the transplantation of these in vitro cultured keratinocytes in different modifications is an established clinical treatment regimen for therapy of extensive wounds. For example, keratinocyte-fibrin-glue-suspensions, mainly consisting of proliferative epidermal basal cells, were used for the treatment of burns in experimental and clinical settings to bypass the disadvantages of conventional sheet grafts. Other approaches in tissue engineering for wound healing aim at the (epi-)dermal repair by the combination of allodermis and biomaterials, i.e. collagen-sponges and microspheres. Due to most recent efforts in keratinocyte culture techniques, developments in tissue engineering, research for novel biomaterials and gene therapy, therapy of chronic wounds may prove to be more efficient. Furthermore, from the socio-economical point of view, overall costs for treatment of chronic wounds could be reduced.

Cell Division↗
PubMedDate not supplied

Effect of ultrasonic assisted lipectomy (UAL) on breast tissue: histological findings.

As the use of ultrasound-assisted liposuction (UAL) increases, the technique grows more popular in breast surgery, especially in reduction mammaplasty and treatment of gynecomastia. The aim of our study was to investigate the effect of UAL on breast tissue using histological examinations, and analyze the effect of this technique on a cellular level. Biopsies from 10 patients undergoing ultrasonically assisted lipectomy prior to classic reduction mammaplasty were taken from the treated areas of the breast. Biopsies were fixed in formalin and embedded in paraffin. Sections were stained with hematoxilin-eosin, and analyzed for defective adipocytes, and the effects of UAL on breast tissue. Untreated breast tissue and breast tissue that had been treated only with conventional aspiration lipectomy served as controls. Sections were analyzed using light microscopy. Compared to the breast tissue treated only with conventional lipectomy, a stronger destruction of the cellular structure of adipocytes could be detected. The destruction was visible even in areas more distant from the aspiration channel. In contrast, the breast tissue was mostly intact, no signs of ultrasonic-induced cellular destruction were visible. The glandular structure was kept intact. Beside the direct mechanical destruction by the probe and the canula, no further alterations of the cellular integrity of the glandular parts were visible. In conclusion our results indicates that UAL is also a safe technique for use in breast surgery. Besides easy handling and improved modelling, the destructive effect of the ultrasound does not include the glandular breast tissue.

Breast↗
PubMedDate not supplied

Single-cell suspensions of cultured human keratinocytes in fibrin-glue reconstitute the epidermis.

To overcome common disadvantages of standard cultured epidermal sheet grafts (CEG) we have developed a new technique of transplanting cultured human keratinocytes suspended as single cells in a fibrin-glue matrix (Keratinocyte-fibrin-glue suspension-KFGS). In an athymic mouse model with reproducible standardized full thickness wounds this new technique was compared directly to CEG. Reepithelialization was similar in both groups, but reconstitution of the dermo-epidermal junction zone, as shown by electron microscopy and immunohistochemistry was significantly enhanced by the fibrin-glue suspension technique. The new KFGS technique is earlier available than sheet grafts, is able to transfer actively proliferative single keratinocytes, and simplifies the application.

Animals↗