Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Biomedical Engineering”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1998

Engineering smooth muscle tissue with a predefined structure.

Nonwoven meshes of polyglycolic acid (PGA) fibers are attractive synthetic extracellular matrices (ECMs) for tissue engineering and have been used to engineer many types of tissues. However, these synthetic ECMs lack structural stability and often cannot maintain their original structure during tissue development. This makes it difficult to design an engineered tissue with a predefined configuration and dimensions. In this study, we investigated the ability of PGA fiber-based matrices bonded at their fiber crosspoints with a secondary polymer, poly-L-lactic acid (PLLA), to resist cellular contractile forces and maintain their predefined structure during the process of smooth muscle (SM) tissue development in vitro. Physically bonded PGA matrices exhibited a 10- to 35-fold increase in the compressive modulus over unbonded PGA matrices, depending on the mass of PLLA utilized to bond the PGA matrices. In addition, the bonded PGA matrices degraded much more slowly than the unbonded matrices. The PLLA bonding of PGA matrices had no effect on the ability of cells to adhere to the matrices. After 7 weeks in culture, the bonded matrices maintained 101 +/- 4% of their initial volume and an approximate original shape while the unbonded matrices contracted to 5 +/- 1% of their initial volume with an extreme change in their shape. At this time the bonded PGA matrices had a high cellularity, with smooth muscle cells (SMCs) and ECM proteins produced by these cells (e.g., elastin) filling the pores between PGA fibers. This study demonstrated that physically bonded PGA fiber-based matrices allow the maintenance of the configuration and dimensions of the original matrices and the development of a new tissue in a predefined three-dimensional structure. This approach may be useful for engineering a variety of tissues of various structures and shapes, and our study demonstrates the importance of matching both the initial mechanical properties and the degradation rate of a matrix to the specific tissue one is engineering.

Animals↗
PubMed2002

A general method for determining the contribution of split pathways in metabolite production in the yeast Saccharomyces cerevisiae.

We describe a simple method using (13)C labeling and NMR spectroscopy to determine the flux contributions of alternative pathways in Saccharomyces cerevisiae that produce the same metabolite with identical labeling patterns. Cells were incubated with a (13)C-labeled precursor for one of the branches, and the absolute enrichment of the product and its metabolic precursor(s) was quantified. The ratio of the absolute enrichment of the product to that of its precursor reflects the contribution of the pathway. The method was applied to the biosynthesis of glycine in yeast, which can occur from threonine via threonine aldolase or from serine via serine hydroxymethyltransferase. [2-(13)C]Aspartate and [2-(13)C]serine were used as labeled precursors for the threonine aldolase and serine hydroxymethyltransferase pathways, respectively. The data show that in cells possessing both pathways, the serine hydroxymethyltransferase pathway contributes 65-75% of the total glycine production. In comparison with other approaches, this method provides an inexpensive, flexible alternative to determining the flux contributions of split pathways under controlled conditions and should have wide applicability in the metabolic engineering of microorganisms.

Amino Acids↗
PubMed2006

Carbon nanotube applications for tissue engineering.

As the field of tissue engineering advances, new tools for better monitoring and evaluating of engineered tissues along with new biomaterials to direct tissue growth are needed. Carbon nanotubes may be an important tissue engineering material for improved tracking of cells, sensing of microenvironments, delivering of transfection agents, and scaffolding for incorporating with the host's body. Using carbon nanotubes for optical, magnetic resonance and radiotracer contrast agents would provide better means of evaluating tissue formation. In addition, monitoring and altering intra and intercellular processes would be useful for design of better engineered tissues. Carbon nanotubes can also be incorporated into scaffolds providing structural reinforcement as well as imparting novel properties such as electrical conductivity into the scaffolds may aid in directing cell growth. Potential cytotoxic effects associated with carbon nanotubes may be mitigated by chemically functionalizing the surface. Overall, carbon nanotubes may play an integral role as unique biomaterial for creating and monitoring engineered tissue.

Animals↗
PubMed1994

Biosensors.

Advances in biosensor technology over the past year have included developments in metalized electrodes, mediated electrochemistry, direct electron transfer, impedance measurement, optical immunosensors, optodes, biomimicry, piezoelectric biosensors, enzyme thermistors, in vivo biosensors, surface characterization, organic-phase biosensors and tissue-based biosensors. Increasingly, molecular biology and engineering are being used in sensor design.

Biomedical Engineering↗
PubMedDate not supplied

Two-dimensional orientational response of smooth muscle cells to cyclic stretching.

It was hypothesized that an orientated cellular tissue for incorporation into vital, functioning hybrid artificial organs can be prepared by periodically applying mechanical stresses on a hybrid tissue. Therefore, the effect of cyclic stretching on the two-dimensional (2-D) orientation response of arterial smooth muscle cells (SMCs) was studied. Smooth muscle cells derived from bovine aortas were seeded onto transparent elastomeric membranes made of polyurethane, and subjected to periodical stretching with various amplitudes from 5-20% at frequencies of 15 to 120 RPM for up to 24 hours. Phase-contrast microscopic views of SMCs were time-lapse video recorded. The orientation angle to the direction of stretching (OA) and cellular longitudinal length (CLL) of individual cells were analyzed by a computerized image processor. After several hours, SMCs subjected to the stress exhibited orientation responses perpendicular to the direction of stretching, evidenced by a significant increase in OA. The responses were more rapid under operating conditions with higher amplitudes and frequencies of stretching. Meanwhile, little significant change in CLL was observed. These findings indicate that an applied mechanical stress induces a significant orientation response, without morphologic alteration of SMCs. The mechanically induced orientation response provides a fundamental basis for more structured hybrid organs and tissue engineering.

Animals↗
PubMedDate not supplied

Analysis & recommendations for a medical engineering department.

A multi-disciplinary task force convened to examine present and future program needs of the Medical Engineering Department at the North Carolina Memorial Hospital, University of North Carolina School of Medicine. The committee recommended changes that would reduce technician turnover, improve continuing education, increase salaries, improve services for patient care and allow the hospital to comply with the requirements of the Joint Commission on the Accreditation of Hospitals. An important by-product of this study approach led to improved communications and work relations with all departments that receive services from the Medical Engineering Department.

Biomedical Engineering↗
PubMedDate not supplied

In vitro engineering of cartilage.

Because adult human cartilage shows poor capacity for repair and regeneration, innovative solutions are required for congenital and acquired degenerative cartilage lesions. Acquired lesions occur in young and old alike, the former being more at risk for sports-related injuries and the latter for age-related degenerative changes. Because cartilage is a relatively simple tissue with respect to its cellular homogeneity and avascularity, it has been a model for research of in vitro engineered tissues. Progress has been slow and obstructed on several levels. The adult chondrocyte has limited capacity for proliferation and has both catabolic and anabolic functions. These metabolic features must be controlled in order for engineered tissue to endure. Use of three-dimensional scaffolds can be combined with regulatory factors (cytokine, extracellular matrix [ECM], and mechanical) to optimize conditions for in vitro engineered cartilage. Cross-disciplinary interactions are likely to accelerate progress and to mediate application of advances made in other fields for consistently successful in vitro engineering of cartilage for all clinical needs.

Adult↗
PubMed1976

Microprocessors in health care: panacea or more effervescent technology?

The impact of microprocessors on medical instrumentation is explored, with particular reference to their role within a health care system that has finite resources. The authors present two examples of microprocessor use from their own experience and attempt to highlight both the merits and the disadvantages of the use of such technology by the hospital medical engineer.

Analog-Digital Conversion↗
PubMed2006

[Cell culture, tissue engineering and regenerative medicine. Part I].

Tissue engineering is an interdisciplinary field that applies the principles and methods of engineering and the cell culture toward the development of biomaterials that restore, maintain or improve tissue function. The amalgamation of engineering and medicine has interested many scientists for at last two hundred years. What was the goal of cell culture? First, for progress in life sciences achievement and subsequent for virology and toxicology development. In vitro studies are done because of many problems with carrying out animal experiments. In this work the authors present the attempts of physicians, anatomopathologists, embryologists and biologists which contributed to fast development of new area in medicine--tissue engineering.

Animals↗
PubMed1991

Implementing a ventricular assist device program. A partnership between nursing and clinical engineering.

VAD programs continue to expand as research evolves and this treatment modality becomes more available. Implementation of these programs requires a strong commitment to team development, collaboration, and ongoing education. We believe that the partnership between nursing and clinical engineering captures these key aspects. This alliance facilitates learning and professional growth and supports overall program goals. Beyond VAD programs, medical and technologic advances will continue to have an impact on the critical care environment, increasing the complexity of patient care. Our successful partnership has set the stage for essential collaboration between nursing and clinical engineering in the future.

Biomedical Engineering↗