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PubMedDate not supplied

Clinical engineering in anesthesia.

It is difficult to measure the effectiveness of a clinical engineering service for anesthesia objectively. Although the monitoring of service costs can justify the maintenance portion of a support effort, the real benefit derived from improvements in patient safety is less tangible. Ultimately, the number of anesthetic mishaps should decrease as a result of clinical engineering involvement in anesthesia. A comprehensive program has been in operation at Massachusetts General Hospital for four years. During that time, about 100,000 anesthesia procedures have been performed without a single patient injury related to malfunctioning equipment or to an operator error involving equipment. Although this fact may not have statistical significance, there is general agreement among the clinical staff that clinical engineering has contributed to the safe induction of anesthesia by fulfilling the goals and objectives described here.

Anesthesia↗
PubMed1983

Comparison of occupational hearing losses among military engineers and their civilian counterparts.

A previous study (Chandler and Fletcher, J. Aud. Res., 1983, 23, 23-32) examined group hearing loss of 209 U.S. Army engineers by comparing current with reference audiograms. The sample was categorized by military occupation specialty, age, and time on job. The present study reports comparable data for 187 civilian engineers on the same Army post exposed to essentially the same noise. These had less hearing loss than their military counterparts. Some reasons are suggested, such as attrition of the civilian workforce because of hearing problems, and a likely greater exposure of the military engineers to noises not job-related. Age was less important than time on the job. Both groups, however, exhibited significantly lower hearing levels than the industrial population of Glorig et al (Am. Acad. Ophthalmol. Otolaryngol., 1957) at the 1954 Wisconsin State Fair, possibly because both military and civilian personnel at this Army post had been for some years in an aggressive hearing conservation program.

Adolescent↗
PubMed1984

Radiographic evidence of asbestos effects in American marine engineers.

Marine engineers undergoing routine annual chest roentgenography showed an unusual prevalence of pleural abnormalities including plaques suggestive of past asbestos exposure. A pilot survey, and a subsequent comprehensive study of the films of more than 5,000 men, showed an overall prevalence of 12% with pleural abnormality (typical calcification or plaque, or diffuse thickening). Prevalence of films classifiable for pneumoconiotic small opacities was negligible--1.2% in the pilot study. Prevalences of pleural abnormality were significantly higher among men with longer union membership, after controlling for age. Older merchant ships contain substantial amounts of asbestos-containing thermal insulation. Marine engineers often remove and reapply insulation, operations known to produce high airborne fiber concentrations. These roentgenographic survey results indicate significant past asbestos exposures of ships' engineering department personnel.

Adult↗
PubMedDate not supplied

Applicability of personnel management concepts to clinical engineering practice.

Personnel management concepts are reviewed for inclusion in clinical engineering basic and continuing education curricula. The management function is evaluated from the aspect of formal and informal leadership, two-way communication, voluntary cooperation, and the direction and discipline of the clinical engineering staff. Prerequisites examined in support of these activities include an effective organizational structure, man-to-job matching, personal needs, and job satisfaction. Steps propounded for stimulating communications between the clinical engineer and his multidisciplinary clients include adjustments to his own role model and to his educational technique so as to accord more with the specific role models of his audience.

Biomedical Engineering↗
PubMed1982

International registration of clinical engineers.

This paper outlines the moves being made by the International Federation for Medical and Biological Engineering to establish an International Clinical Engineering Board. The purpose of this board is to stimulate, through the establishment of National Examining Authorities, international agreement on the minimum requirements needed for the registration or certification of professional clinical engineers.

Biomedical Engineering↗
PubMed1994

Problems in the introduction of genetically engineered microorganisms into the environment.

The use and release of genetically engineered microorganisms (GEMs) into the environment, usually the agricultural environment, is increasing exponentially. Potential applications of GEMs include crop production, pest management, degradation of environmental pollutants, mining and mineral recovery, and others. Several strategies of molecular and cellular biotechnology, such as recombinant DNA techniques, nuclear microinjection and cell fusion may be used to modify bacteria and fungi for useful purposes. The benefits expected from release of genetically engineered microorganisms, if safely applied, might be substantial in various fields. However, a safe introduction of GEMs into the environment requires full environmental and ecological risks assessment. Because of the wide scope of genetic engineering targets this review will focus on the application of GEMs potentially useful in agricultural practices (crop nutrition, pest and disease control) and ecological problems associated with the introduction of alien microorganisms into the environment.

Agriculture↗
PubMed1994

Genetically engineered in vitro systems for biotransformation studies.

In order to understand cytochrome P450-mediated metabolism of xenobiotics such as drugs and pollutants, several cell systems are genetically engineered for metabolic competence by cloning cDNAs encoding cytochrome P450 and other enzymes and by heterologous expression in bacterial, yeast, and mammalian cells. Genetically engineered cell systems are defined for the cDNA enzyme function. In conjunction with cell intrinsic properties, these genetically engineered cell systems can be used for the assessment of metabolism-dependent pharmacological and/or toxicological effects.

Animals↗
PubMed1993

Molecular engineering: applications to the clinical laboratory.

Advances in cellular and molecular biology methods have led to the molecular engineering of novel human biomolecules, some of which have been successfully applied to the documentation of clinical laboratory assays. Here I describe the use of engineered chimeric antibodies in the clinical immunology laboratory in three principal applications: (a) as reference proteins to document the specificity of clinical assay reagents, be used as reagent-grade purified antigens, and facilitate the epitope mapping of antibody reagents; (b) as calibration proteins to assign mass/volume estimates to proposed antibody standards; and (c) as interference proteins to study the effects of naturally occurring autoantibodies on the accuracy and sensitivity of current clinical assays. The model recombinant proteins used for these illustrations are chimeric antibodies with a defined V-region specificity for one of two haptens (nitrophenyl or dansyl) and C-region domains covering a spectrum of human isotypes. I also describe a panel of mutant human IgG1-4 anti-dansyl chimeric antibodies that have been genetically engineered with swapped, deleted, or point-mutated wild-type C-region exons and used as specialized reagents for mapping the epitopes to which clinically used human IgG-specific monoclonal antibodies bind. Finally, the use of a recombinant human IgG1 anti-human IgE Fc chimeric antibody to simulate human IgG anti-IgE autoantibody interference in assays of total serum IgE is investigated.

Animals↗
PubMed1996

Role of neutrophils and lymphocytes in inhibition of a mouse mammary adenocarcinoma engineered to release IL-2, IL-4, IL-7, IL-10, IFN-alpha, IFN-gamma, and TNF-alpha.

Impressive inhibition of tumor growth has been observed after transduction of cytokine genes into tumor cells. Secreted cytokines do not affect the proliferation of a tumor directly but activate a host immune reaction strong enough to overcome its oncogenic capacity. However, the reaction mechanisms activated are difficult to interpret; because these mechanisms have been derived from experiments with different tumors, comparisons are hindered. To compare the reactive mechanisms induced by each cytokine, BALB/c mice were challenged with the parental cells of the syngeneic spontaneous mammary adenocarcinoma TSA, or with TSA cells engineered to release IL2, IL4, IL7, IL10, IFN alpha, IFN gamma, and TNF alpha, and the tumor growth area was studied histologically, ultrastructurally, and immunohistochemically. These observations were integrated with data on the growth and rejection patterns of TSA cells in mice depleted of natural killer (NK) cells, granulocytes, CD4+, or CD8+ lymphocytes. The rejection of TSA-IL2 and TSA-TNF alpha cells was associated with the massive presence of neutrophils, that of TSA-IL4 and TSA-IL7 cells with neutrophils and very small areas of colliquative necrosis, and that of TSA-IFN alpha and TSA-IL10 cells with extensive areas of ischemic-coagulative necrosis and some neutrophils. TSA-IFN gamma cells displayed a delay in growth, but were not rejected. Their growth areas comprised necrotic zones of ischemic necrosis devoid of neutrophils. The selective depletion experiments demonstrated that rejection of engineered TSA cells depends on several leukocyte populations. The weight of each population varied with the secreted cytokine, although neutrophils and CD8+ lymphocytes constantly played the major role. Employment of the same tumor line engineered with the genes of different cytokines showed that each cytokine evokes a distinct reaction and that tumor inhibition results from a complex mechanism in which neutrophils and CD8+ lymphocytes and ischemic necrosis are of primary importance.

Adenocarcinoma↗
PubMed1996

Genetic engineering of Minnesota superfish.

There is a chronic need to develop growth-enhanced fish for aquaculture. To meet this need we have developed techniques for genetically engineering fish to grow larger and faster. We found that the major difficulty in genetically engineering fish is the extremely high rate of mosaicism due to the late integration of transgenes into the genome. This delay also reduces the chances of passage of the transgene through the germ line. Consequently, we have engineered new vectors and mechanisms for accelerating the rate of integration of exogenous DNA into fish chromosomes.

Animals↗
PubMed1997

Both resting and activated B lymphocytes expressing engineered peptide-Ig molecules serve as highly efficient tolerogenic vehicles in immunocompetent adult recipients.

To test the potential for genetically transferring foreign sequences into autologous cells for specific modulation of immunity, we have generated transgenic mice that express an engineered peptide-IgG construct in the peripheral B cell compartment. B cells from these mice express and can be stimulated to secrete a murine IgG1 chain grafted with residues 12-26 from bacteriophage A cI repressor protein in-frame at the heavy chain N terminus. As expected, 12-26-IgG transgenic mice are profoundly tolerant to the peptide at both the T and B cell levels. Importantly, the injection of transgenic whole spleen, purified B cells, or even bone marrow cells into normal, immunocompetent adults results in profound peptide-specific T cell tolerance, as well as partial B cell tolerance. Injection of LPS-activated peptide-Ig-expressing B cells was uniquely effective at diminishing an ongoing humoral immune response typical of both Th1 and Th2 help. Since fixed transgenic B cells were tolerogenic, this suggests that secretion of the fusion protein is not required for tolerogenicity. These results show that an engineered self Ig, as well as B lymphocytes expressing epitopes from such a fusion protein, can regulate both cellular and humoral immune responses. Moreover, these studies provide the basis for expressing foreign epitopes on engineered IgG for the induction of gene-transferred tolerogenesis in autoimmune states.

Age Factors↗
PubMed1997

Evaluation of genetically engineered herpes simplex viruses as oncolytic agents for human malignant brain tumors.

Earlier studies have shown that genetically engineered herpes simplex viruses (e.g., HSV-1) are effective in killing malignant tumor cells both in vitro and in various murine tumor models. This report focuses on a panel of five genetically engineered viral mutants of the gamma(1)34.5 gene, which was shown previously to cause reduction in viral replication and associated neurovirulence of HSV. These include R3616, which has both copies of gamma(1)34.5 deleted, R4009, which has a stop codon inserted after codon 28 in both copies of the gamma(1)34.5 gene, R849, which contains a lacZ gene inserted in place of the gamma(1)34.5, R908, which lacks 41 codons in frame after codon 72 of the gamma(1)34.5, and R939, which carries a stop codon precluding the translation of the COOH-terminal domain of the gamma(1)34.5 gene. We report the following: (a) all five mutant HSVs were avirulent in experimental animals but were cytotoxic for human tumor cells in vitro and in vivo; (b) the gamma(1)34.5- HSV replicated in human glioma cells almost as efficiently as wild-type HSV-1(F) based on replication assays, in situ hybridization for viral DNA, and expression of infected cell protein 27; (c) capacity of mutant HSVs to kill human cells derived from glioblastoma multiforme (CH-235MG, D-37MG, D-54MG, D-65MG, U-251MG, U-373MG, and SK-MG-1), anaplastic astrocytoma (Hs-683), anaplastic glioma (U-87MG and U-138MG), gliosarcoma (D-32GS), or normal human astrocytes demonstrated that glioma cells varied in their susceptibility to HSV-mediated cytotoxicity and that cultured astrocytes were two to three orders of magnitude less susceptible to killing than were malignant glia; and (d) scid mice, which received 0.5 or 5 x 10(6) plaque-forming units of R4009, either were coinoculated at the time of intracranial transplantation with 106 U251MG or D-54MG human glioma cells or received the cells intratumorally 5 days after tumor induction and experienced significant increases in median survivals, with no histopathological indication of an infectious encephalitic process. Genetically engineered gamma(1)34.5- HSV mutants appear to be a potentially safe biotherapeutic agent for experimental treatment of uniformly fatal malignant brain tumors.

Acyclovir↗
PubMed1997

The World Wide Web--a new tool for biomedical engineering education.

An ever-increasing variety of materials (text, images, videos, and sound) are available through the World Wide Web (WWW). While textbooks, which are often outdated by the time they are published, are usually limited to black and white text and images, many supplemental materials can be found on the WWW. The WWW also provides many resources for student projects. In BAE 465: Biomedical Engineering Applications, student teams developed WWW-based term projects on biomedical topics, e.g. biomaterials, MRI, and medical ultrasound. After the projects were completed and edited by the instructor, they were placed on-line for world-wide access if permission for this had been granted by the student authors. Projects from three classes have been used to form the basis for an electronic textbook which is available at http:@www.eos.ncsu.edu/bae/research/blanchard /www/465/textbook/. This electronic textbook also includes instructional objectives and sample tests for specific topic areas. Student projects have been linked to the appropriate topic areas within the electronic textbook. Links to relevant sites have been included within the electronic textbook as well as within the individual projects. Students were required to link to images and other materials they wanted to include in their project in order to avoid copyright issues. The drawback to this approach to copyright protection is that addresses can change making links unavailable. In BAE 465 and in BAE 235: Engineering Biology, the WWW has also been used to distribute instructional objectives, the syllabi and class policies, homework problems, and abbreviated lecture notes. This has made maintaining course-related material easier and has reduced the amount of paper used by both the students and the instructor. Goals for the electronic textbook include the addition of instructional simulation programs that can be run from remote sites. In the future, biomedical engineering may be taught in a virtual classroom with participation by an instructor and students from many different parts of the world.

Biomedical Engineering↗
PubMed1998

Tissue engineering and the development of Apligraf, a human skin equivalent.

In recent years, skin grafting has evolved from the initial autograft and allograft preparations to biosynthetic and tissue-engineered living skin replacements. This review details the pioneering work of numerous investigators that led to the following precursors of tissue-engineered skin replacement: cultured autologous keratinocyte grafts, cultured allogeneic keratinocyte grafts; autologous/allogeneic composites, acellular collagen matrices, and cellular matrices. It also discusses the rationale for the development of the newer products and describes the technical advances leading to the development of Apligraf, a tissue-engineered human skin product.

Biomedical Engineering↗
PubMed2025

A comprehensive review of genomic-scale genetic engineering as a strategy to improve bacterial productivity.

Bacterial genome engineering has evolved to provide increasingly precise, robust and rapid tools, driving the development and optimization of bacterial production of numerous compounds. The field has progressed from early random mutagenesis methods, labour-intensive and inefficient, to rational and multiplexed strategies enabled by advances in genomics and synthetic biology. Among these tools, CRISPR/Cas has stood out for its versatility and its ability to achieve precision levels ranging from 50% to 90%, compared to the 10-40% obtained with earlier techniques, thereby enabling remarkable improvements in bacterial productivity. Nevertheless, like its predecessors, it still demands continuous refinement to reach full maturity. In this context, the present review addresses the lack of a unified overview by summarizing historical milestones and practical applications of genomic engineering tools in bacteria. It integrates diverse approaches to provide a comprehensive perspective on the evolution and prospects of these fundamental biotechnological tools.

Bacteria↗
PubMed2000

Influence of growth factors on tissue-engineered pediatric elastic cartilage.

OBJECTIVE: To investigate the influence of growth factors on tissue-engineered pediatric human elastic cartilage relative to potential clinical application. DESIGN: Controlled study. SUBJECTS: Eleven children ranging in age from 5 to 15 years provided auricular elastic cartilage specimens measuring approximately 1 x 1 x 0.2 cm and weighing approximately 100 mg. INTERVENTIONS: Three million chondrocytes were plated into 4 groups of Ham F-12 culture medium: group 1, Ham F-12 culture medium only; no growth factors (control group); group 2, Ham F-12 culture medium and basic fibroblast growth factor; group 3, Ham F-12 culture medium and transforming growth actor beta; and group 4, Ham F-12 culture medium and a combination of both growth factors. At 3 weeks, the cells were harvested and mixed with a copolymer gel of polyethylene glycol and polypropylene oxide (Pluronic F-127). The cell solution was injected subcutaneously into athymic mice. The constructs were harvested at up to 22 weeks of in vivo culture and histologically analyzed. RESULTS: The average number of cells generated in vitro was as follows: group 1, 12 million; group 2, 40 million; group 3, 7 million; and group 4, 35 million. Group 2 in vivo gross specimens were the largest and heaviest. Histologically, the control group and the basic fibroblast growth factor group (groups 1 and 2) exhibited characteristics compatible with normal auricular cartilage; groups 3 and 4 demonstrated cellular disorganization and moderate to severe fibrous tissue infiltration. CONCLUSIONS: Basic fibroblast growth factor demonstrates the greatest positive influence on the in vitro and in vivo growth of engineered pediatric human auricular cartilage. The results suggest that basic fibroblast growth factor has the potential for clinical application in which a goal will be to generate a large volume of tissue-engineered cartilage from a small donor specimen in a short period of time and of a quality similar to native human elastic cartilage.

Adolescent↗
PubMed2000

Internal support of tissue-engineered cartilage.

BACKGROUND: Auricles previously created by tissue engineering in nude mice used a biodegradable internal scaffold to maintain the desired shape of an ear. However, the biodegradable scaffold incited a compromising inflammatory response in subsequent experiments in immunocompetent animals. OBJECTIVE: To test the hypothesis that tissue-engineered autologous cartilage can be bioincorporated with a nonreactive, permanent endoskeletal scaffold. MATERIALS AND METHODS: Auricular elastic cartilage was harvested from Yorkshire swine. The chondrocytes were isolated and suspended into a hydrogel (Pluronic F-127) at a cell concentration of 5 x 10(7) cells/mL. Nonbiodegradable endoskeletal scaffolds were formed with 1 of 5 polymers: (1) high-density polyethylene, (2) soft acrylic, (3) polymethylmethacrylate, (4) extrapurified Silastic, and (5) conventional Silastic. Three groups were studied: (1) a control group using only the 5 polymers, (2) the 5 polymers enveloped by Pluronic F-127 only, and (3) the implants coated with Pluronic F-127 seeded with chondrocytes. All constructs were implanted subdermally; implants containing cells were implanted into the same animal from which the cells had been islolated. The implants were harvested after 8 weeks of in vivo culture and histologically analyzed. RESULTS: Only implants coated by hydrogel plus cells generated healthy new cartilage. With 3 polymers (high-density polyethylene, acrylic, and extrapurified Silastic), the coverage was nearly complete by elastic cartilage, with minimal fibrocartilage and minimal to no inflammatory reaction. The Food and Drug Administration-approved conventional Silastic implants resulted in fragments of fibrous tissue mixed with elastic cartilage plus evidence of chronic inflammation. The polymethylmethacrylate implant was intermediate in the amount of cartilage formed and degree of inflammation. CONCLUSIONS: This pilot technique combining tissue-engineered autologous elastic cartilage with a permanent biocompatible endoskeleton demonstrated success in limiting the inflammatory response to the scaffold, especially to high-density polyethylene, acrylic, and extrapurified Silastic. This model facilitates the potential to generate tissue of intricate shape, such as the human ear, by internal support. Arch Otolaryngol Head Neck Surg. 2000;126:1448-1452

Animals↗
PubMed1999

Poly(alpha-hydroxyl acids)/hydroxyapatite porous composites for bone-tissue engineering. I. Preparation and morphology.

Tissue engineering has shown great promise for creating biological alternatives for implants. In this approach, scaffolding plays a pivotal role. Hydroxyapatite mimics the natural bone mineral and has shown good bone-bonding properties. This paper describes the preparation and morphologies of three-dimensional porous composites from poly(L-lactic acid) (PLLA) or poly(D,L-lactic acid-co-glycolic acid) (PLGA) solution and hydroxyapatite (HAP). A thermally induced phase separation technique was used to create the highly porous composite scaffolds for bone-tissue engineering. Freeze drying of the phase-separated polymer/HAP/solvent mixtures produced hard and tough foams with a co-continuous structure of interconnected pores and a polymer/HAP composite skeleton. The microstructure of the pores and the walls was controlled by varying the polymer concentration, HAP content, quenching temperature, polymer, and solvent utilized. The porosity increased with decreasing polymer concentration and HAP content. Foams with porosity as high as 95% were achieved. Pore sizes ranging from several microns to a few hundred microns were obtained. The composite foams showed a significant improvement in mechanical properties over pure polymer foams. They are promising scaffolds for bone-tissue engineering.

Adhesiveness↗