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Bioengineering organs using small intestinal submucosa scaffolds: in vivo tissue-engineering technology.

Tissue engineering is a promising field of research that has the potential to revolutionize urinary bladder reconstruction. Currently, two techniques for the induction of bladder regeneration are being researched. The first, the in vivo technique, involves the use of a biodegradable scaffold that the host bladder can use to remodel and regenerate. This technique takes advantage of the cell's natural ability to heal or regenerate itself back to a normal state. The second technology, the in vitro technique, involves establishment of primary cell cultures from the host's native bladder. These cells are seeded on a biodegradable scaffold to create a composite graft that is then transplanted back into the host for continuation of the regeneration process. Clearly, both techniques have advantages and disadvantages, and both will have some role in future urinary reconstruction. To date, the most successful results utilizing in vivo techniques have been with small intestinal submucosa (SIS). In this article, we discuss in vivo tissue engineering technology and the preclinical studies that have been performed utilizing SIS for urinary tract regeneration.

Animals↗

Achieving the promise of clinical engineering.

Clinical engineering has failed to make the impact expected of it in the early 1970's. This failure has occurred because clinical engineering has not matured as any discipline must to achieve professional status. It does not embody a clearly understood set of capabilities. It is not based on a well-defined body of knowledge. It does not have a professional society directly representing it. This condition can be remedied by the establishment of a professional society for clinical engineering that can educate consumers about the capabilities of clinical engineers, guide providers in designing clinical engineering curricula, and promote increased involvement of clinical engineers in all high-technology areas of hospitals and in the decision-making process at their institutions.

Biomedical Engineering↗

Evaluation of alarm systems for medical equipment.

The provision of automatic alarm systems on medical equipment is generally designed to supplement the user's ability to monitor a variety of device and patient variables simultaneously. The potential value of such systems in improving the safety and efficacy of medical care is accompanied by the potential for false reliance on or other misuse of the alarm systems. Therefore the alarm provisions become an important aspect of clinical engineering assessment of equipment with respect to selection, user training, hazard analysis, and the provision of effective and appropriate preventive maintenance programs.

Biomedical Engineering↗

Am empirical study of selected cost measures of clinical engineering service effectiveness.

The growing demand for more and better healthcare service greatly expands the role of medical equipment in providing health services more effectively. The purpose of introducing clinical engineering programs in hospitals was to improve the effectiveness of healthcare institutions' utilization and management of medical technology. Over the last decade, the role of clinical engineering has grown in importance as a component of hospitals and the healthcare delivery system. Hospital administrators currently put a strong emphasis on cost effectiveness of clinical engineering services, to reduce the cost of acquisition and maintenance of equipment. Unfortunately, the lack of a commonly accepted definition of cost effectiveness has resulted in a certain amount of confusion over how the performance of clinical engineering services can or should be measured. The results presented in this paper should assist hospital administrators and clinical engineering program managers to establish a common understanding of what "cost effectiveness" means and how it can be achieved.

Biomedical Engineering↗

Skeletal volume enhancement: implants and osteotomies.

PURPOSE OF REVIEW: Facial plastic surgeons are concerned with improving or restoring function and form. Most surgeons perform primarily soft tissue procedures, which alone are often sufficient. However, deficiencies in the underlying craniomaxillofacial skeleton must also be addressed. Facial skeletal augmentation remains an essential aspect of cosmetic and reconstructive surgery. This article reviews the basic alloplastic biomaterials available for facial volume enhancement, discusses the zygomatic sandwich osteotomy for malar augmentation, and describes recent applications of distraction osteogenesis in the craniomaxillofacial region. An update in tissue engineering and computer modeling is also provided. RECENT FINDINGS: High-porosity expanded polytetrafluoroethylene has been developed to provide a softer feel with less shrinkage and migration because of better biointegration and cellular ingrowth. Long-term results with porous polyethylene have demonstrated superior biocompatibility and minimal complications. Hydroxyapatite cement has been associated with an immunoguided delayed inflammatory reaction that leads to thinning of the overlying skin and exposure of the implant.Applications of distraction osteogenesis are rapidly expanding and include deformities of the mandible, midface, and cranium. There has been a trend toward the use of internal hardware, and internal devices are being developed to deliver a greater degree of vector control. Biodegradable devices have been developed to eliminate the second surgical procedure necessary for hardware removal. In the future, successful tissue engineering could eliminate many of the drawbacks associated with implants and osteotomies. The ability to stimulate stem cells to generate autogenous bone has been demonstrated in the laboratory. A novel application of computer technology that integrates laser surface scanning and digitizing with computer-aided design and manufacturing to produce facial prostheses has been described. SUMMARY: An abundance of alternatives exist for skeletal volume enhancement including alloplastic implants, standard osteotomies, and distraction osteogenesis. The surgeon must evaluate the pros and cons of each technique in the context of each individual patient to determine the most appropriate option. Technologic advances in biomaterials, distraction hardware, computer modeling, and tissue engineering will continue to supply the surgeon's repertoire with improved methods to augment and restore the craniomaxillofacial skeleton.

Absorbable Implants↗

Keeping up with...new roles in health care: the clinical engineer.

Most managers are well aware of the costs related to purchasing, installing and maintaining sophisticated medical instrumentation. Can these costs be reduced by hiring an in-house clinical engineer? The authors consider a number of alternatives in addressing this one area of soaring medical costs.

Biomedical Engineering↗

Re-engineering the process of medical imaging physics and technology education and training.

The extensive availability of digital technology provides an opportunity for enhancing both the effectiveness and efficiency of virtually all functions in the process of medical imaging physics and technology education and training. This includes degree granting academic programs within institutions and a wide spectrum of continuing education lifelong learning activities. Full achievement of the advantages of technology-enhanced education (e-learning, etc.) requires an analysis of specific educational activities with respect to desired outcomes and learning objectives. This is followed by the development of strategies and resources that are based on established educational principles. The impact of contemporary technology comes from its ability to place learners into enriched learning environments. The full advantage of a re-engineered and implemented educational process involves changing attitudes and functions of learning facilitators (teachers) and resource allocation and sharing both within and among institutions.

Biomedical Engineering↗

Tissue engineering of biphasic joint cartilage transplants.

In isolated posttraumatic or idiopathic joint defects the chondral layers and adjacent subchondral spongy bone are usually destructed. For regeneration we suggest the in vitro formation of a cartilage-coated biomaterial carriers (biphases) in order to fill the correspondingjoint defects. In this study Biocoral, a natural coralline material made of calcium carbonate, and calcite, a synthetic calcium carbonate, were used as supports for the cultivation of bovine chondrocytes in a three-dimensional polymer fleece. The cell-polymer-structure was affixed to the biomaterial with a fibrin-cell-solution. The artificial cartilage formed a new matrix and fused with the underlying biomaterial. The results indicate a promising technical approach to anchor tissue engineered cartilage in joint defects.

Animals↗

Development of a three-dimensional transmigration assay for testing cell--polymer interactions for tissue engineering applications.

The ability of synthetic or natural scaffolds to support invasion of cells from surrounding tissue is a key parameter for tissue engineering (TE). In this study, the migration of fibroblasts, chondrocytes, and osteoblasts into biodegradable polymer scaffolds was evaluated using a novel, three-dimensional (3-D) transmigration assay. This assay is based on a cell-populated contracted collagen lattice with a biodegradable polymer scaffold implanted at the center of the collagen gel. Cell migration into the scaffolds was assessed both quantitatively and qualitatively following various time lengths in culture using image analysis. Chondrocytes, incorporated within the collagen lattice, migrated into polymer scaffolds, when cultured both statically or in a rotating bioreactor. However, the bioreactor cultures resulted in a significantly greater cell invasion as compared to static cultures. There was a cell density-dependent osteoblast migration from collagen lattice into polymer scaffold, when tested in the transmigration assay. In addition, polymer scaffolds, treated with or without recombinant human platelet-derived growth factor (rh-PDGF-BB) were evaluated for fibroblast migration. The presence of rh-PDGF-BB resulted in significantly greater fibroblast invasion as compared to untreated scaffolds. Our studies suggest that the transmigration model provides a rapid system for testing cell invasion of potential scaffolds for tissue engineering applications.

Becaplermin↗

Engineering challenges in the development of an encapsulated cell system for treatment of type 1 diabetes.

Implantation of glucose-responsive, insulin-secreting cells is promising in providing a treatment for type I diabetes, which is more effective, less invasive, and potentially less costly than conventional insulin injections. However, in spite of promising results with animal studies, a clinical product or therapeutic procedure based on encapsulated cells does not yet exist. This is because a number of barriers remain to be addressed, which include a source of functional cells, a stable, biocompatible membrane offering immune protection to the implant, a construct architecture ensuring cell viability and construct function, and the engineering of immune acceptance of the construct post-implantation. This article reviews these barriers and the current state-of-the-art, with special emphasis on the engineering challenges involved, and discusses possible ways to tackle the complex problems currently preventing this approach from reaching clinical practice.

Alginates↗

Scaffold precoating with human autologous extracellular matrix for improved cell attachment in cardiovascular tissue engineering.

Cell attachment to a scaffold is a precondition for the development of bioengineered valves and vascular substitutes. This attachment is generally facilitated by the use of precoating factors, but some can cause toxic or immunologic side effects. Autologous extracellular matrix (ECM) is used as a precoating factor in our study. Ascending aortic tissue was cultured to obtain human myofibroblasts. Autologous ECM was extracted from the same aortic tissue. Poly(glycolic acid) (PGA) scaffolds were precoated with autologous ECM, human serum, or poly-L-lysine; the control group was pretreated with phosphate buffered saline (PBS). Myofibroblasts were seeded onto each scaffold, and the cell attachment was assayed and compared. Compared with the control group, precoating with human serum, poly-L-lysine, and ECM increased number of attached cells by 24%, 53%, and 48%, respectively. Differences between precoating groups were significant (p < 0.01), except for ECM versus poly-L-lysine. Scanning electron microscopy also demonstrated the high degree of cell attachment to the PGA fibers on scaffolds precoated with ECM and poly-L-lysine. Precoating polymeric scaffold with autologous human extracellular matrix is a very effective method of improving cell attachment in cardiovascular tissue engineering without the potential risk of immunologic reactions.

Aorta↗

Skills required for clinical engineering practice: results of a survey.

In order to provide information to individuals conducting or planning educational programs in clinical engineering, a survey of skills required for practice in this field was carried out. A total of 127 responses from university-based (44) and practicing (83) clinical engineers were received. The results were tabulated separately for these two groups. The survey form was divided into two parts: basic skills and clinical engineering skills. The responses indicated an emphasis on medical instrumentation, basic life science (physiology and anatomy) information, and organizational and quipment control skills.

Biomedical Engineering↗

Emerging problems in clinical engineering education.

Following an analysis of the differences between Clinical Engineering educational programs and classical engineering education, emerging difficulties in Clinical Engineering education are examined. A shortage of Clinical Engineers is projected along with a possible impact on the nation's hospitals in the next decade. Solutions for these difficulties are proposed.

Biomedical Engineering↗

DRGs and prospective payment: an introduction to the issues facing clinical engineering programs.

DRGs--these letters, spoken as frequently as they now are, may sound familiar and perhaps even sinister. They have rapidly become the driving force of the health care system. Medicare is the largest purchaser of health care and has engineered a financing program based upon DRGs. Since other insurers are joining the program, the health care industry, along with its suppliers and clients, will never again be treated as it was in the past. As participants in the system, our work and our careers will also be changed. Yet, as with any change, there will be opportunities to acquire knowledge, to grow professionally, and to contribute to society. If hospitals are to provide quality care in a cost-effective and efficient manner, it will be both because of and in spite of technology. The appropriate selection, use, and maintenance of technology is an intrinsic part of the system. The clinical engineer's role will be to contribute technical and managerial expertise in support of the institution--in other words, in the management of technology.

Biomedical Engineering↗

Quantitative ultrasound can assess the regeneration process of tissue-engineered cartilage using a complex between adherent bone marrow cells and a three-dimensional scaffold.

Articular cartilage (hyaline cartilage) defects resulting from traumatic injury or degenerative joint disease do not repair themselves spontaneously. Therefore, such defects may require novel regenerative strategies to restore biologically and biomechanically functional tissue. Recently, tissue engineering using a complex of cells and scaffold has emerged as a new approach for repairing cartilage defects and restoring cartilage function. With the advent of this new technology, accurate methods for evaluating articular cartilage have become important. In particular, in vivo evaluation is essential for determining the best treatment. However, without a biopsy, which causes damage, articular cartilage cannot be accurately evaluated in a clinical context. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the cartilage are measured by introducing an ultrasonic probe during arthroscopy of the knee joint. The purpose of the current study was to determine the efficacy of this ultrasound system for evaluating tissue-engineered cartilage in an experimental model involving implantation of a cell/scaffold complex into rabbit knee joint defects. Ultrasonic echoes from the articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the percentage maximum magnitude (the maximum magnitude of the measurement area of the operated knee divided by that of the intact cartilage of the opposite, nonoperated knee; %MM) was used as a quantitative index of cartilage regeneration. Using this index, the tissue-engineered cartilage was examined to elucidate the relations between ultrasonic analysis and biochemical and histological analyses. The %MM increased over the time course of the implant and all the hyaline-like cartilage samples from the histological findings had a high %MM. Correlations were observed between the %MM and the semiquantitative histologic grading scale scores from the histological findings. In the biochemical findings, the chondroitin sulfate content increased over the time course of the implant, whereas the hydroxyproline content remained constant. The chondroitin sulfate content showed a similarity to the results of the %MM values. Ultrasonic measurements were found to predict the regeneration process of the tissue-engineered cartilage as a minimally invasive method. Therefore, ultrasonic evaluation using a wavelet map can support the evaluation of tissue-engineered cartilage using cell/scaffold complexes.

Animals↗

Chemical engineering in medicine in North America.

An examination has been made of the involvement of chemical engineers in medicine in North America. Fields of Study and subjects of research are briefly given in tabular form and the general statistical picture of chemical engineering in medicine discussed. Further details of the workers and references to their published work can be obtained from the author if required.

Biomedical Engineering↗

Assembling medical devices: the essential steps for success.

Designers of complex medical devices face many challenges in taking a product from prototype to mass production. There are numerous obstacles that can bring a project to a standstill and at the same time take it considerably over budget. This article will examine some of the engineering issues related to medical device assembly, such as the management of the project, choice of component and assembly system suppliers, and quality.

Biomedical Engineering↗