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At least 37 records · Page 2Linked to original sources
PubMed1989

Skin reactions to irritants assessed by non-invasive bioengineering methods.

Pathophysiological components of irritant contact dermatitis caused by 3 chemically-different irritants were investigated. 20 healthy volunteers were patch tested with sodium lauryl sulphate, nonanoic acid and hydrochloric acid on the flexor side of the upper arm. The skin response was evaluated after 24, 48 and 96 h by visual scoring and measured by the following bioengineering methods: transepidermal water loss measurement, electrical conductance for measurement of skin hydration, laser Doppler flowmetry for measurement of cutaneous blood flow and 20 MHz ultrasound A-scan for measurement of skin thickness. In spite of homogeneous inflammatory responses, significant differences in the severity of the injury to the skin barrier function caused by the different irritants were found. Also significant differences between irritants were found in the time course of development of maximum irritant reactions. Bioengineering methods indicating inflammatory responses (measurement of blood flow and skin thickness) were helpful in quantifying the irritant response in general, while bioengineering methods indicating epidermal damage (measurement of TEWL and electrical conductance) were helpful in classifying the individual irritants.

Adult↗
PubMed2002

The National Institute of Biomedical Imaging and Bioengineering: history, status, and potential impact.

This paper describes the history, current status, and objectives and potential impact of the new National Institute of Biomedical Imaging and Bioengineering (NIBIB). Three of the authors (Hendee, Chien, and Maynard) have been involved over several years in the effort to raise the identity of biomedical imaging and bioengineering at the National Institutes of Health. The fourth author (Dean) is the Acting Director of the newly formed NIBIB. These individuals have an extensive collective knowledge of the events that led to formation of the NIBIB, and are intimately involved in shaping its objectives and implementation strategy. This special report provides a historical record of activities leading to establishment of the NIBIB, and an accounting of present and potential advances in biomedical engineering and imaging that will be facilitated and enhanced by NIBIB. The National Institute of Biomedical Imaging and Bioengineering represents a "coming of age" of biomedical engineering and imaging, and offers great potential to expand the research frontiers of these disciplines to unparalleled heights.

Academies and Institutes↗
PubMed2002

Bioengineering of therapeutic aerosols.

The new field of therapeutic aerosol bioengineering (TAB), driven primarily by the medical need for inhaled insulin, is now expanding to address medical needs ranging from respiratory to systemic diseases, including asthma, growth deficiency, and pain. Bioengineering of therapeutic aerosols involves a level of aerosol particle design absent in traditional therapeutic aerosols, which are created by conventionally spraying a liquid solution or suspension of drug or milling and mixing a dry drug form into respirable particles. Bioengineered particles may be created in liquid form from devices specially designed to create an unusually fine size distribution, possibly with special purity properties, or solid particles that possess a mixture of drug and excipient, with designed shape, size, porosity, and drug release characteristics. Such aerosols have enabled several high-visibility clinical programs of inhaled insulin, as well as earlier-stage programs involving inhaled morphine, growth hormone, beta-interferon, alpha-1-antitrypsin, and several asthma drugs. The design of these aerosols, limited by partial knowledge of the lungs' physiological environment, and driven largely at this stage by market forces, relies on a mixture of new and old science, pharmaceutical science intuition, and a degree of biological-impact empiricism that speaks to the importance of an increased level of academic involvement.

Administration, Inhalation↗
PubMedDate not supplied

Bioengineering at the University of Strathclyde.

Bioengineering is, of course, no longer regarded as 'new'. Many groups exist in many centres in the UK and worldwide. The writer considers himself particularly fortunate in having been involved since 1960 in bioengineering research, teaching and development following a very satisfying period as a lecturer in mechanics for engineering students. On hindsight, the most important feature has been the pleasure of association with a succession of talented, intelligent and strongly motivated academic colleagues and students devoted to research and development in the field of bioengineering.

Biomedical Engineering↗
PubMedDate not supplied

Bioengineering: the advent of metabiology (part II).

The ability to modify or replace organs or functions and to intervene in the transmission of hereditary characteristics is a fundamental turning point in the development of living organisms and of bioengineering. The theoretical potential of metabiology--the intervention from the outside on functions, organs and sub-organs through artificial organs as well as genetic engineering-- is briefly reviewed. Specific goals are proposed and engineering capabilities needed to achieve them are assessed. The impact on engineering and bioengineering of metabiology is examined and some fundamental issues of public policy concerning metabiology and bioengineering are proposed. (Part I of this paper was published in the July-Sept. 1981 issue of the Journal of Clinical Engineering.).

Artificial Organs↗
PubMed1988

Bioengineered human growth hormone supports limb regeneration in the hypophysectomized newt Notophthalmus viridescens.

It is well documented that growth hormone (GH) replacement therapy will restore normal limb regeneration to hypophysectomized adult newts. However, it is also known that the GH preparations used in previous reports were contaminated by other pituitary hormones shown to support regeneration when administered free of GH. The recent availability of bioengineered human GH was studied for its ability to restore the regenerative capacity to hypophysectomized newts. Five days posthypophysectomy adult newts were subject to forelimb amputation distal to the elbow. Animals were divided into three groups (n greater than 20). Each received one of three GH preparations: pituitary-derived bovine GH, pituitary-derived human GH, or bioengineered human GH. GH was administered via intraperitoneal injection (0.029 IU/50 microliters) on alternate days for either the first 5 days (total of 3 injections) or for 35 days (total of 18 injections). Pituitary-intact and hypophysectomized control newts were subjected to forelimb amputation and injected with hormone diluent. All newts that received GH demonstrated normal limb regeneration to the early digitiform stage by 35 days postamputation. None of the hypophysectomized control newts showed any evidence of regeneration. We conclude that GH alone can restore the ability to undergo normal limb regeneration to hypophysectomized newts.

Amputation, Surgical↗
PubMed1999

Strategies for bioengineering the development and metabolism of glandular tissues in plants.

Glandular tissues in plants produce a wide variety of commercially important chemicals. We review specific model systems that can be exploited for bioengineering the development and metabolism of these specialized structures, and the economic considerations that must be satisfied to permit commercially viable bioengineering approaches to specific chemicals and that constrain the choice of production systems.

Biotechnology↗
PubMed2002

Human chronic wounds treated with bioengineered skin: histologic evidence of host-graft interactions.

Bioengineered skin is being used to successfully treat a variety of wounds. Randomized controlled clinical trials have shown that a living bilayered skin construct (BSC), consisting of human neonatal keratinocytes and fibroblasts in a collagen matrix, was able to accelerate complete closure of both venous and diabetic ulcers. BSC was particularly effective in difficult-to-heal wounds of long duration. In patients treated with BSC, no obvious signs of gross clinical rejection were observed. Testing of these treated patients showed no BSC-specific immune response and no immune response to bovine collagen or alloantigens expressed on keratinocytes and fibroblasts. However, very little is known about the histologic changes that occur after BSC has been placed on human wounds. We report our preliminary histologic observations in this uncontrolled study of a cohort of 11 patients with 14 wounds treated with BSC in whom biopsy specimens of the grafted sites were obtained at least 2 weeks after application of the construct. The etiology of these ulcers varied from arterial or venous disease to an extensively and poorly healing burn wound. Histologically, thickening of the grafted bioengineered skin was seen in all samples where residual BSC could be identified. Mucin deposition was noted in the dermal layer of the wounds and BSC in 13 of the 14 specimens examined. Unexpectedly, and in spite of good clinical outcome, 4 of the 14 specimens exhibited a foreign body-like granulomatous response. There was no history of prior exposure to BSC in the 4 patients who had a granulomatous response. These early histologic observations suggest that stimulatory interactions develop between BSC and the wound. The consistently found deposition of mucin may point to a fetal pattern of wound repair associated with the neonatal cells in BSC.

Aged↗
PubMedDate not supplied

Bioengineering education, 1986--Part I.

This paper, as Part I of a continuing series in Bioengineering Education, reviews eighteen various college level programs in the Western United States. Two-year, four-year, and graduate programs are discussed, but an evaluation or comparison is not made. Rather, the intent of this paper is to illustrate, by region, the variety and breadth of Bioengineering Education available today in the U.S. and Canada. Each school is listed separately; contact information and the types of degrees granted are included. The requirements of each school are also presented.

Biomedical Engineering↗
PubMedDate not supplied

Bioengineering education, 1986--Part IV.

This paper describes college-level Bioengineering programs located in the states of Indiana, Michigan, and Ohio. Seventeen schools are represented, including two-year, four-year undergraduate, and graduate programs. As the fourth part of the Journal's series on Bioengineering Education, the intent of this paper is not to evaluate each program, but to briefly describe the breadth of biomedical and related engineering programs available today.

Biomedical Engineering↗
PubMedDate not supplied

Bioengineering education, 1986--Part V.

As Part V of the Journal's series on Bioengineering Education in the U.S., this paper describes college-level programs in the states of Connecticut, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont. Each program is concerned with the broad areas of science and engineering that work together to solve medical problems. The purpose of this series is not to evaluate each program, but to illustrate the breadth of Bioengineering and related programs available today.

Biomedical Engineering↗
PubMedDate not supplied

Bioengineering education in Canada, 1988.

As a companion article to the Journal of Clinical Engineering's series on Bioengineering Education in the United States, this paper describes the biomedical engineering and biomedical engineering technology programs in Canada. The purpose of the article is not to evaluate each program, but to illustrate the breadth of bioengineering and related programs available today in this country. While biomedical engineering technology programs are offered at the college level, the Canadian philosophy toward biomedical engineering is slightly different from that found in the United States: in Canada, biomedical engineering is offered only at the graduate level to qualified applicants with a previous degree in engineering, science, medicine, or dentistry.

Biomedical Engineering↗
PubMed1995

Blood-contacting biomaterials: bioengineering viewpoints.

The investigation of blood-contacting biomaterials is an important challenge and is relevant for an improvement in the clinical application of biomaterials. With the purpose of improved clinical treatment, bioengineering viewpoints of blood-contacting biomaterials cover the material options and selection, the utilization of materials, the development of materials with better properties, and processing characteristics, and the design of relevant evaluation procedures. The bioengineering objective remains that of achieving an enhanced understanding of the relationship between a biomaterial and the biological response.

Biocompatible Materials↗
PubMed1998

Proper statistical analysis of transepidermal water loss (TEWL) measurements in bioengineering studies.

In irritancy studies, measurement of transepidermal water loss (TEWL) is a widely used technique to assess barrier function. Using inappropriate statistical methods, however, leads to loss of information and misinterpretation of results. In this paper, we discuss some problems and pitfalls when using a suitable statistical technique for most designs in bioengineering studies, analysis of variance (ANOVA): multiple comparisons, choice of sample size and violation of statistical assumptions. For clarification of these points, a practical example will be given. Using the proposed adequate statistical methods correctly will, although accompanied by increased complexity, increase the efficiency of bioengineering studies.

Analysis of Variance↗
PubMed2002

The National Institute of Biomedical Imaging and Bioengineering: history, status, and potential impact.

In December 2000, President Clinton signed legislation establishing the National Institute of Biomedical Imaging and Bioengineering (NIBIB). This action was the result of a multidecade effort of the biomedical imaging and engineering communities to gain increased recognition for biomedical imaging and engineering research within the National Institutes of Health and to enhance the impact of these disciplines on the health and well-being of people worldwide. Beginning in January 2001, several activities were initiated to form NIBIB into a real asset for researchers in biomedical imaging and engineering. These activities reflect a recognition that research in biomedical imaging and bioengineering has the potential of positively influencing research in many other biomedical disciplines, as well as directly affecting the welfare of people everywhere. This potential impact is discussed in this report, together with the history and present status of the formation of NIBIB.

Academies and Institutes↗
PubMed1999

Biomedical device design discovery team approach to teaching physiology to undergraduate bioengineering students.

Teaching effectiveness is enhanced by generating student enthusiasm, by using active learning techniques, and by convincing students of the value of acquiring knowledge in the area of study. We have employed a technique to teach physiology to bioengineering students that couples students' enthusiasm for their chosen field, bioengineering, with an active learning process in which students are asked to design a biomedical device to enhance, replace, or create a new cellular or organ system function. Each assignment is designed with specific constraints that serve to direct students' attention to specific areas of study and that require students to create original designs. Preventing students from using existing designs spurred student invention and enthusiasm for the projects. Students were divided into groups or "design discovery teams" as might be done in a biomedical device industry setting. Students then researched the physiological issues that would need to be addressed to produce an acceptable design. Groups met with faculty to brainstorm and to obtain approval for their general design concepts before proceeding. Students then presented their designs to the instructors in a structured, written outline form and to the class as a 10-minute oral presentation. Grades were based on the outline, oral presentation, and peer evaluations (group members anonymously rated contributions of other members of their team). We believe that this approach succeeded in generating enthusiasm for learning physiology by allowing the students to think creatively in their chosen field of study and that it has resulted in students developing a more thorough understanding of difficult physiological concepts than would have been achieved with a traditional didactic lecture approach.

Animals↗
PubMedDate not supplied

Assessment of 'dry skin': current bioengineering methods and test designs.

Dry skin is a frequent problem in dermatology and a sign of dysfunction of the epidermis, especially of the stratum corneum as the morphological equivalent of the skin barrier. It may occur as an individual disposition or as the leading symptom of atopic dermatitis or ichthyosis. Besides the visual examination of the skin, various bioengineering methods have been developed to assess the different pathological and adaptive changes in the skin. In addition to the assessment of skin humidity, barrier function and desquamation, the quantification of skin surface topography and the mechanical properties of skin are suitable methods to characterize a dry skin condition. For clinical assessment of moisturizing products and emollients the parameters of investigation have to be defined and integrated in an adapted study design depending on the composition and content of the active agent in the test product. Newly developed cosmetic products have to be investigated for safety and efficacy. Modern bioengineering methods are suitable to fulfill these challenges.

Animals↗
PubMed2003

Improved left ventricular aneurysm repair with bioengineered vascular smooth muscle grafts.

BACKGROUND: Recurrent ventricular dilatation can occur after surgical repair of a left ventricular (LV) aneurysm. Use of an autologous bioengineered muscle graft to replace resected scar tissue may prevent recurrent dilatation and improve cardiac function. METHODS: Vascular smooth muscle cells (SMCs, 5 x 10(6) cells) from rat aortas were seeded onto synthetic PCLA (sponge polymer of epsilon-caprolactone-co-L-lactide reinforced with knitted poly-L-lactide fabric) patches and cultured for 2 weeks to allow tissue formation. Syngenic rats underwent proximal left coronary artery ligation to create a transmural myocardial scar. Four weeks after coronary ligation, cell-seeded patches (n=15) or unseeded patches (n=12) were used for a modified endoventricular circular patch plasty (EVCPP) repair of the infarct area. Ligated controls (n=14) and nonligated normal rats (n=10) had sham surgeries without EVCPP. Cardiac function was assessed by echocardiography and isolated Langendorff heart perfusion. Graft histology and morphology was also assessed. RESULTS: After 8 weeks in vivo, seeded patches were thicker (P<0.05) and smaller in area (P<0.003) than unseeded patches. Only seeded patches had prominent elastic tissue formation (P<0.001) in association with SMCs. LV systolic function by echocardiography was improved in the seeded group compared with both unseeded (P<0.002) and control groups (P<0.0001). LV volumes in both patch repair groups were comparable but were significantly smaller (P<0.05) than controls. LV distensibility tended toward improvement in the seeded group as compared with unseeded hearts, but the difference did not achieve statistical significance (P=0.06). CONCLUSIONS: Surgical repair with muscle-cell seeded grafts reduced abnormal chamber distensibility and improved LV function after myocardial infarction as compared with unseeded grafts. Bioengineered muscle grafts may be superior to synthetic materials for the surgical repair of LV scar.

Animals↗