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PubMed1993

The laryngeal mask airway: tool for airway management.

The laryngeal mask airway (LMA) is possibly the most significant recent advance in airway management. Designed to be passed into the hypopharynx without a laryngoscope, the LMA was conceived after bioengineering principles were applied to postmortem specimens of the adult larynx. The LMA has gained widespread, worldwide popularity and was approved for use in the United States in 1992. Sound knowledge of this device is important for all health care workers involved in airway management because it may become a standard item of resuscitation equipment when intubation is difficult. Nurses in the PACU may also be involved in management of anesthetized patients who still have an LMA in place. This article acquaints the reader with the LMA; reviews its design, uses, and limitations; and details some of the controversies related to its use in the PACU. Policies about the LMA need to be defined by PACU nurses and anesthesiologists according to the best information available and the particular requirements of the individual PACU.

Humans↗
PubMed1995

NIH consensus conference. Cochlear implants in adults and children.

OBJECTIVE: To provide clinicians and other health care providers with a current consensus on the benefits, limitations, and technical and safety issues that need to be considered in the use of cochlear implants. PARTICIPANTS: A nonfederal, nonadvocate, 14-member consensus panel representing the fields of otolaryngology, audiology, speech-language pathology, pediatrics, psychology, and education, and including a public representative. In addition, 24 experts in auditory anatomy and physiology, otolaryngology, audiology, aural rehabilitation, education, speech-language pathology, and bioengineering presented data to the consensus panel and a conference audience of 650. EVIDENCE: The literature was searched through MEDLINE and an extensive bibliography of references was provided to the panel and the conference audience. Experts prepared abstracts with relevant citations from the literature. Scientific evidence was given precedence over clinical anecdotal experience. CONSENSUS: The panel, answering predefined consensus questions, developed its conclusions based on the scientific evidence presented in open forum and the scientific literature. CONSENSUS STATEMENT: The panel composed a draft statement that was read in its entirety and circulated to the experts and the audience for comment. Thereafter, the panel resolved conflicting recommendations and released a revised statement at the end of the conference. The panel finalized the revisions within a few weeks after the conference. CONCLUSIONS: Cochlear implantation improves communication ability in most adults with severe-to-profound deafness and frequently leads to positive psychological and social benefits as well. Currently, children at least 2 years old and adults with profound deafness are candidates for implantation. Cochlear implant candidacy should be extended to adults with severe hearing impairment and open-set sentence discrimination that is less than or equal to 30% in the best-aided condition. Access to optimal education and (re)habilitation services is important for adults and is critical for children to maximize the benefits available from cochlear implantation.

Adult↗
PubMedDate not supplied

Cochlear implants in adults and children.

OBJECTIVE: To provide clinicians and other health care providers with a current consensus on the benefits, limitations, and technical and safety issues that need to be considered in the use of cochlear implants. PARTICIPANTS: A non-Federal, nonadvocate, 14-member consensus panel representing the fields of otolaryngology, audiology, speech-language pathology, pediatrics, psychology, and education and including a public representative. In addition, 24 experts in auditory anatomy and physiology, otolaryngology, audiology, aural rehabilitation, education, speech-language pathology, and bioengineering presented data to the consensus panel and a conference audience of 650. EVIDENCE: The literature was searched through Medline and an extensive bibliography of references was provided to the panel and the conference audience. Experts prepared abstracts with relevant citations from the literature. Scientific evidence was given precedence over clinical anecdotal experience. CONSENSUS: The panel, answering predefined consensus questions, developed its conclusions based on the scientific evidence presented in open forum and the scientific literature. CONSENSUS STATEMENT: The panel composed a draft statement that was read in its entirety and circulated to the experts and the audience for comment. Thereafter, the panel resolved conflicting recommendations and released a revised statement at the end of the conference. The panel finalized the revisions within a few weeks after the conference. CONCLUSIONS: Cochlear implantation improves communication ability in most adults with severe to profound deafness and frequently leads to positive psychological and social benefits as well. Currently, children at least 2 years old and adults with profound deafness are candidates for implantation. Cochlear implant candidacy should be extended to adults with severe hearing impairment and open-set sentence discrimination that is less than or equal to 30 percent in the best aided condition. Access to optimal education and (re)habilitation services is important for adults and is critical for children to maximize the benefits available from cochlear implantation.

Adult↗
PubMed1996

Computerized patient record for a department of respiratory rehabilitation.

A computerized patient record (CPR) system plays an essential support role in the efficient functioning of the clinical and research services of a medical centre. We report the experience gained in developing a CPR for the Respiratory Rehabilitation Department (RRD) of the Tradate Medical Center of the Salvatore Maugeri Foundation, with specific reference to Out-patient (OP) and In-patient (IP) Units. The CPR was developed locally under the guidance of the Bioengineering Department. Several items implemented and strategies adopted are described and grouped in relation to broader objectives, such as the improvement of health-care quality, the enhancement of personnel productivity and reduction in costs, the support of clinical and health service research and the accommodation of future developments. In particular, we describe the design and implementation of anamnestic, physical and admission data collection, specifically orientated to respiratory diseases. Daily use of the CPR in the OP and IP units and its potential outcome for research and management support are also studied in detail. On the basis of our experience (1,251 out-patient examinations, 650 in-patient clinical admission cards), the computerized patient record seems a useful way of providing better health-care and a more comprehensive coverage of the rehabilitation process of patients in a Respiratory Rehabilitation Department.

Delivery of Health Care↗
PubMed1996

Differential irritant skin responses to topical retinoic acid and sodium lauryl sulphate: alone and in crossover design.

Topically applied all-trans retinoic acid (RA) is often associated with skin irritation. A detailed quantification of RA-induced functional changes in stratum corneum is, however, still limited. Using non-invasive bioengineering techniques of measurements of transepidermal water loss (TEWL), stratum corneum hydration and cutaneous blood flow (CBF), we quantified the irritant effects of 0.05% and 0.1% RA in ethanol on normal skin compared with 1% sodium lauryl sulphate (SLS) in water as a model irritant in a 24-h occlusive patch-test assay. Additionally, in order to document data possibly related to the mechanism of action, skin responses to both compounds applied in tandem was also investigated over 18 days. The extent of the irritant response to 0.05 and 0.1% RA, respectively, were similar, implying analogous irritation potency. While RA caused more intense scaling than SLS, other skin responses to RA were significantly weaker than those due to SLS. An increase in TEWL, on day 7, in RA-exposed sites indicates a secondary delayed impairment of the stratum corneum (SC) barrier. In a tandem-design assay, pretreatment with RA appeared to reduce the irritant effects of SLS on SC hydration and CBF. In contrast, pre-exposure to SLS showed a synergestic response in erythema, scaling and TEWL. Our results demonstrate that RA, like SLS, is capable of impairing SC water barrier function, which may be responsible, in part, for the irritation associated with its topical use. However, the distinctive biological responses to these compounds suggest a different mode of action of RA and SLS. In addition, the precise reason for the unique results observed in the tandem-design assays is not clear.

Administration, Topical↗
PubMed1996

Identification of foot-and-mouth disease virus-free regions by use of a standardized enzyme-linked immunoelectrotransfer blot assay.

OBJECTIVE: To assess the potential of a highly sensitive enzyme-linked immunoelectrotransfer blot (EITB) assay to monitor persistent foot-and-mouth disease (FMD) viral activity in a livestock population. DESIGN: Cattle sera were obtained in Uruguay in 1992, 2 years after the last outbreaks of FMD. Prevalence of antibodies, as assessed by the EITB assay and by the conventional immunodiffusion in agarose gel method (virus infection-associated antigen [VIAA] test), was correlated with occurrence of FMD. SAMPLE POPULATION: A total of 2,194 serum samples were acquired from animals at different farms and were separated according to age: animals < and > 2 years old. PROCEDURE: Specific antibodies to replicating virus were detected by use of the EITB assay that utilizes a set of 5 bioengineered nonstructural antigens as serologic probes. RESULTS: EITB-positive reaction was restricted to sera from cattle in areas with the last outbreaks of FMD during 1989-1990, and to animals > 2 years old. All cattle sera from regions that were free of clinical FMD since (or prior to) 1989 were EITB negative. In contrast, use of the VIAA test yielded a rather homogeneous distribution of positive results when regions without FMD during the last 4 years preceding sample collection were compared with those affected during 1989-1990. VIAA test-positive reaction was also found in sera from animals born after the last FMD outbreak. CONCLUSIONS: The EITB assay proved to be a sensitive, specific, safe, rapid, and economic tool for monitoring the progress of FMD eradication programs, mainly because it eliminated false-positive results form the VIAA test.

Animals↗
PubMed1995

Ex vivo expansion of human peripheral blood progenitors.

Culture of human hematopoietic progenitors on a large scale could lead to several clinical applications within the near future, including the production of differentiated and functional cells, the increase in the number of early progenitors, especially stem cells, with such use as gene transfer, or the improvement of grafts used to limit the hematological toxicity associated with high-dose chemotherapy. In this case, one can still distinguish different objectives: improvement of grafts that contain low numbers of progenitors because of prior chemotherapies or because of marrow involvement for example, and qualitative changes in the graft content that would allow to envision the disappearance, or the further reduction, in the duration of absolute neutropenia that follows delivery of high dose chemotherapy ("nadir rescue"), despite substitution of mobilized blood cells to marrow cells and the in vivo use of hematopoietic growth factors. Additional advantages may be related to tumor purging in autologous expanded cells, and to the change in the ratio between hematopoietic progenitors and immunocompetent cells in allogeneic expanded populations. Therefore it appears that in vitro expansion currently raises two types of questions: the first ones are related to the definition of clinical or biological endpoints to be achieved, the second ones are related to "bioengineering", and deal with the efficiency and safety of progenitor cell cultures to be used for clinical applications. We here present preliminary results preparing future pilot clinical studies with ex vivo cultured human hematopoietic cells.

Antigens, CD↗
PubMed1996

Functional analyses of the stratum corneum in scars. Sequential studies after injury and comparison among keloids, hypertrophic scars, and atrophic scars.

OBJECTIVE: To characterize the functional properties of the stratum corneum (SC) of various scars. DESIGN: A prospective cohort study. SETTING: University hospital medical center. PATIENTS: Thirty-two consecutive patients surgically treated for various skin diseases and 26 consecutive patients with hypertrophic scars or keloids. MAIN OUTCOME MEASURES: Noninvasive bioengineering measurements of functional properties of the SC, such as transepidermal water loss (TEWL), high-frequency conductance, and SC turnover time. RESULTS: The SC barrier function assessed by TEWL was found to be a better parameter for the functional evaluation of scars than the hydration state of the skin surface measured by high-frequency conductometry. In general, the SC on the scars of deeper wounds in the dermis took longer to normalize functionally than the SC on the scars of superficial wounds, especially on the high compared with the abdomen. Thus, elevated levels of TEWL observed on scars at the donor sites of split-thickness grafts normalized between 200 and 400 days in contrast to fewer than 50 days for those of subepidermal erosions. Both TEWL and high-frequency conductance remained high in hypertrophic scars and keloids, and the SC involved showed a faster turnover time than that of adjacent normal skin. CONCLUSIONS: Scars, a proliferative change of the dermis, can be objectively evaluated according to functional abnormalities of the SC, because the dermis has a close relationship with the epidermis and with the SC. The functional characteristics of the SC of fresh scars and those of hypertrophic scars and keloids resemble those of retinoid-treated skin, rather than those found in epidermal hyperproliferative conditions such as psoriasis and dermatitis.

Abdomen↗
PubMed1997

[Gene-directed biologically active substances (antisense oligonucleotides and their derivatives)].

Results of studies carried out over the last eight years under the Russian State Scientific and Technical Program "New Methods in Bioengineering" are reviewed. New addressing constructions formed by a tandem of two or more oligonucleotides on a target nucleic acid are described. The reactivity of the tandem is enhanced due to the stabilization of some components, either by attachment of polyaromatic systems (method of effectors) or by the formation of a reaction center, which occurs when the components of the active center draw together into a tandem. Reagents which are oligonucleotide derivatives are also described, in particular a derivative of the antibiotic bleomycin, which is capable of catalytic cleavage of the target. Evidence is presented that oligonucleotides interact with the proteins of cells and living organisms, including the receptor proteins discovered in the course of this research, the T-helper CD4 receptor, immunoglobulins, and some growth factors.

Base Sequence↗
PubMedDate not supplied

Food biotechnology's challenge to cultural integrity and individual consent.

Consumer response to genetically altered foods has been mixed in the United States. While transgenic crops have entered the food supply with little comment, other foods, such as the bioengineered tomato, have caused considerable controversy. Objections to genetically engineered food are varied, ranging from the religious to the aesthetic. One need not endorse these concerns to conclude that food biotechnology violates procedural protections of consumer sovereignty and religious liberty. Consumer sovereignty, a principle especially valued in this country, requires that information be made available so each individual or group may make food choices based on their own values. And as yet, there is no policy provision for informing consumers about the degree to which food has been genetically engineered.

Animals↗
PubMed1976

Mathematics and the surgeon.

The surgeon uses elementary mathematics just as much as any other educated layman. In his professional life, however, much of the knowledge and skill on which he relies has had a mathematical strand in its development, possibly woven into the supporting disciplines such as physics, chemistry, biology, and bioengineering. The valves and limitations of mathematical models are examined briefly in the general medical field and particularly in relation to the surgeon. Arithmetic and statistics are usually regarded as the most immediately useful parts of mathematics. Examples are cited, however, of medical postgraduate work which uses other highly advanced mathematical techniques. The place of mathematics in postgraduate and postexperience teaching courses is touched on. The role of a mathematical consultant in the medical team is discussed.

Computers↗
PubMed1998

Living skin equivalents and their application in wound healing.

Living skin equivalents are the combination of the bioengineering and tissue-transplantation sciences. Their uses have applications in aiding wound healing for ulcerations caused by thermal injury, diabetic neuropathy, venous hypertension, and pressure. Products can be divided into keratinocyte sheets, dermal replacements, or composite material. Past and current studies give the Food and Drug Administration and health care providers valuable data relating to these products' efficacy in the wound healing arena.

Cells, Cultured↗
PubMed1997

[Soluble TNF-alpha receptors].

Soluble cytokine receptors are more general phenomena and play a wider physiological role in the regulation of the immune system than previously recognized. Soluble TNF receptors--sTNF-Rp55 and sTNF-Rp75 by ability to bind to free TNF-alpha might play a regulatory role in a variety of normal and abnormal reactions mediated by TNF-alpha. Increase of sTNF-Rs levels have been observed in the serum of patients with a different diseases. Measurement of soluble TNF receptors concentrations seems to be a significant indicator in prognostic estimation of some diseases. Additionally, bioengineered soluble receptors may prove useful as specific cytokine-inhibiting therapeutic agents.

Humans↗
PubMed1998

[Pharma-clinics. Doping with erythropoietin or the misuse of therapeutic advances].

Sport performance depends on the capacity of oxygen transport to the exercising skeletal muscles. Performance may be increased thanks to an haematocrit augmentation, either by training in high altitude, using blood transfusions, or injecting erythropoietin (Epo). Since the synthesis of Epo by bioengineering, doping with recombinant human Epo has become popular in sports in general, and in cycling in particular. This new kind of doping might have been responsible for several sudden deaths in young athletes, essentially in racing cyclists. Until now, such a doping is hardly to be detected. However, it should deserve careful consideration from both public health authorities and sports communities in order to stop what could become a real plague.

Altitude↗
PubMed1998

Identification of the in vivo topically applied "human-identical" ceramides included in negatively charged liposomes.

Among the different classes of human epidermal lipids, Ceramides are definitely one of the most important and studied class judging from the significant amount of scientific information accumulated over the years, specially after being established its crucial role in skin physiology and pathophysiology. However, a clear demonstration of its usefulness resulting from the regular use of these substances included in topical formulations, either in a therapeutical or in a cosmetological perspective have not been entirely achieved. Many difficulties are normally present, from its origin to formulation and protocol design, and to the experimental demonstration of the relative efficacy of these compounds. In the present paper, the authors developed a systematic approach to the problem, using "human-identical" ceramides included into negatively charged liposomes, which were topically applied in a normalised panel of human healthy volunteers. Biological analysis were conducted with non-invasive methodologies by means of bioengineered reference methods (Epidermal capacitance, Evaporimetry; Light Transmission Profilometry; and High Resolution Ultrasonography). The experimental methodologies included the study of acute effects as well as the study of the effects resulting from continuous repeated application of formulations, basically expressed in terms of epidermal water content and skin surface profile. Additionally, an eventual protective "barrier" reinforcement resulting from ceramide application was also assessed by means of a SLS (5% solution) challenge-test. This systematic although preliminary approach indicated that these compounds do have a considerable impact on human skin physiology, justifying further research to clarify their potential use in human cutaneous health.

Adult↗
PubMed2005

Formation of a nucleus pulposus-cartilage endplate construct in vitro.

Intervertebral disc (IVD) degeneration is a common problem and treatment options for persistent symptomatic disease are limited. Tissue engineering is being explored for its ability to reconstitute the functional components of the IVD. The purpose of this study was to determine whether it was possible to form in vitro a triphasic construct consisting of nucleus pulposus (NP), cartilage endplate (CEP), and a porous calcium polyphosphate (CPP) bone substitute. Bovine articular chondrocytes were placed on the top surface of a porous CPP construct and allowed to form cartilage in vitro. Nucleus pulposus cells were then placed onto the in vitro-formed hyaline cartilage. At 24 h scanning electron microscopy demonstrated that the NP cells maintained their rounded morphology, similar to NP cells placed directly on porous CPP. At 8 weeks histological examination of the triphasic constructs by light microscopy showed that a continuous layer of NP tissue had formed and was fused to the underlying cartilage tissue, which itself was integrated with the porous CPP. The incorporation of the cartilage layer was beneficial to the construct by improving tissue attachment to the CPP, as demonstrated by increased peak load and increased energy required for failure during shear loading when compared to a biphasic construct composed of nucleus pulposus-bone substitute only. This study demonstrates that it is possible to generate a multi-component construct with the incorporation of a CEP-like layer resulting in improved bone substitute-to-IVD tissue interface characteristics.

Animals↗
PubMed2006

Repair of osteochondral defects with biphasic cartilage-calcium polyphosphate constructs in a sheep model.

There has been interest in developing novel biological treatments to repair focal cartilage defects. We have developed a method of forming biphasic constructs ("osteochondral"-type plug) in vitro consisting of cartilaginous tissue, formed on and anchored to the intended articulation surface of a porous ceramic substrate. The purpose of this study was to evaluate the biochemical and biomechanical properties and morphology of in vitro-formed biphasic constructs 3 and 9 months after implantation into 4mm diameter full thickness osteochondral defects in the trochlear groove of sheep stifles. The implants withstood loading in vivo up to 9 months with evidence of fusion to adjacent native cartilage and fixation by bone ingrowth into the ceramic substrate. The cartilage layer was eroded from those implants that were proud to the joint surface. Control implants (ceramic only) had fibrous tissue on the articulating surface after implantation for 3-4 months. Neither the cellularity nor proteoglycan content of the implanted cartilage, when it remained, changed significantly between 3 and 9 months and the collagen content increased slightly. The elastic equilibrium modulus of the cartilage improved with time with the greatest improvement (10-fold) occurring early during the first 3-4 months after implantation. This study suggests that biphasic constructs may be suitable to repair joint defects as the implants were maintained up to 9 months in sheep. Importantly the mechanical properties of the implanted cartilage improved significantly after implantation suggesting that cartilage can mature in vivo after implantation. The results indicate that further study of this treatment approach is warranted to attempt to overcome the technical surgical difficulties identified in this study.

Animals↗