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PubMed1982

Recombinant DNA technology for the preparation of subunit vaccines.

Recombinant DNA technology appears to be on the verge of producing safe and effective protein vaccines for animal and human diseases. The procedure is applicable to most viruses because their isolated surface proteins generally possess immunogenic activity. Strategies used for the preparation and cloning of the appropriate genes depend on the characteristics of the viral genomes: whether DNA or RNA; their size, strandedness, and segmentation; and whether messenger RNA are monocistronic or polycistronic. Cloned surface proteins of foot-and-mouth disease and hepatitis B viruses are being tested for possible use as practical vaccines. Two doses of the cloned foot-and-mouth disease viral protein have elicited large amounts of neutralizing antibody and have protected cattle and swine against challenge exposure with the virus. Surface proteins have also been cloned for the viruses of fowl plague, influenza, vesicular stomatitis, rabies, and herpes simplex. Cloning is in progress for surface proteins of viruses causing canine parvovirus gastroenteritis, human papillomas, infectious bovine rhinotracheitis, Rift Valley fever, and paramyxovirus diseases. In addition, advances in recombinant DNA and other facilitating technologies have rekindled interest in the chemical synthesis of polypeptide vaccines for viral diseases. The bioengineering of bacterial vaccines is also under way. Proteinaceous pili of enterotoxigenic Escherichia coli are being produced in E coli K-12 strains for use as vaccines against neonatal diarrheal diseases of livestock.

Animals↗
PubMed1983

Continuous ambulatory peritoneal dialysis in the physically disabled.

Continuous ambulatory peritoneal dialysis (CAPD) has been increasingly used as maintenance home dialysis by patients in end-stage chronic renal failure since it was first described in 1976. The procedure is hazardous in the physically disabled and blind and in non-compliant patients. This paper describes 2 patients, one with rheumatoid arthritis and the other with Volkmann's ischaemic contracture of the left forearm, who are able to carry out CAPD successfully with the aid of bioengineering.

Adolescent↗
PubMed1980

An infrared system for determining ocular position.

Bioengineering research in the Electronics Division of the Denver Research Institute has centered around the development of an ocular controlled communications device for the severely handicapped. The means for accurate determination of eye position for use in communication/control applications have been investigated by various groups for at least ten years. A highly satisfactory device for eye tracking has been developed in our laboratories and is currently undergoing clinical evaluation as part of a communications system. An infrared LED is mounted on the nose pad of an ordinary pair of eyeglass frames. This LED floods the cornea with light after reflection from the inside surface of an unground eyeglass lens in the frames. The cornea acts as a convex mirror and reflects the light (via the inside surface of the eyeglass (lens) into an image transducer mounted on the bow of the frames. The image transducer is a 32 x 32 cell (1k) dynamic RAM. Utilizing TTL scanning circuitry, the position of the eye can be determined from the address of the illuminated cell of the RAM.

Communication Devices for People with Disabilities↗
PubMed1984

Treatment of the multiply injured patient: plans for treatment and problems of major trauma.

Certain principles involved in the treatment of fractures have stood the test of time. The thrust of modern orthopaedics has been to decrease morbidity by combining these principles with developments in physiology, bioengineering, radiology, and antibiotics. The goal remains anatomic bone union without infection and normal joint and muscle function. The surgeon's mission is to achieve this goal. For the multiply injured patient, survival depends on the quality of care. Surgical orientation permits one to stabilize the fractures and restore the patient to activities of daily living. Multiple fractures set the stage for multiple organ failure, and, as we have discussed, stabilization reduces the incidence of these problems. Basically, open fractures must be stabilized with plaster, traction, or surgery. Multiple fractures need rigid stabilization, which can be achieved with various techniques without jeopardizing limb or life. A simple, comprehensive plan should be implemented when the patient arrives in the emergency room. Treatment requires an interdisciplinary approach, with the surgeon heading a team of physicians, nurses, and technicians capable of handling the complications of each organ system. Teamwork and dedication to excellence by all involved will decrease mortality and morbidity. Survival is to be anticipated. If we have restored the anatomy early, before any organ failure, we are then ready to begin rehabilitation and achieve a much finer and enduring end result for the injured patient.

Anti-Bacterial Agents↗
PubMed1983

The cardiac diagnostic unit. A new approach to patient care.

The Cardiac Diagnostic Unit at Duke University Hospital brings together multiple diagnostic services for evaluation of patients with cardiovascular disease. This Unit is a combined effort of the departments of Medicine, Radiology, Surgery, Bioengineering, and Computer Sciences. The reasons for the establishment of the Unit are discussed, along with some illustrative case studies.

Aged↗
PubMedDate not supplied

[Principles of designing ophthalmological devices for the study of operator activity].

Electronic image synthesizers and imagers with colour CRT's offer a considerable scope for the study of the visual system. However, the synthesis of optimum bioengineering systems assumes a number of requirements for ophthalmic devices should be fulfilled. Such requirements have been induced in general and particular technical principles of designing ophthalmic devices.

Color Perception Tests↗
PubMed1980

A prosthetic myocardium for repair of localized defects of the left ventricle: concept and hemodynamic feasibility.

As an approach to the treatment of patients with large but circumscribed akinetic or dyskinetic regions in the left ventricular myocardium as sequelae of acute myocardial infarction, excision of the defect and implantation of a mechanical functional equivalent of myocardium is suggested. Experimental investigation of this technique is described. Hemodynamic data from a series of dog experiments indicate that activation of the prosthetic myocardium after excision of the left ventricle is followed by improvement in various hemodynamic parametres of interest. Although substantial experimental work must be completed and difficult bioengineering problems solved, preliminary results have encouraged us to continue our investigations of the prosthetic myocardium. An imposing array of treatment methods is now available to the clinician who must deal with the sequelae of acute myocardial infarction. Selecting from pharmacologic, electrophysiologic, and surgical approaches the physician can in many instances design a treatment plan precisely tailored to the clinical problem. Large left ventricular aneurysms and their functional equivalents of ventricular dyskinesis or hypokinesis continue, however, to represent a class of problems in which established techniques have been less than satisfactory. Surgical excision with closure of the defect is regarded as effective for small aneurysms, but such procedures may so compromise cardiac output in patients with large ones as to be unacceptable. Unfortunately, it is just the latter group in which medical palliation is least likely to be effective in managing congestibe failure, angina, and other pathophysiologic manifestations. A relatively unusual approach derived from in-series techniques of mechanical assistance to the failing circulation (1) offers the theoretical possibility of a treatment tailored to the problem of a large ventricular aneurysm. Experimental investigation of this technique in the Surgical Research Laboratory at the Sinai Hospital of Detroit has progressed to the point that a report of our experiences to date may be of interest.

Animals↗
PubMed1995

Prefabricated flaps: experimental and clinical review.

Prefabricated flaps are a useful tool for the reconstructive surgeon and present a number of advantages: 1. Specific preferred tissue composites, regardless of their native vascular origin, can be transferred as free or pedicled flaps. 2. Larger flaps of specialized tissue may be transferred safely. 3. Donor-site morbidity is reduced. 4. The functional outcome for the patients may be more satisfactory. The various methods of flap prefabrication include vascular induction through stage transfer; pretransfer delay, expansion, and grafting; the use of alloplastic materials; and tissue bioengineering. We have reviewed both the experimental and clinical research on flap prefabrication, describing the theory, technique, and advantages of each method.

Animals↗
PubMed1976

Status report on instrumentation useful for craniofacial research.

This report reviews briefly State-of-the-Art of certain bioengineering instrumentation useful in craniofacial research and assessment. Brief reviews are included in the areas of Radiography, Electromyography, Intra-oral air flow/pressure, Lingual/palatal pressure, Oral-sensory perception, Visualization techniques, Acoustic processing, and Digital Computers. It should be obvious, even from this limited effort, that the variety and quality of available equipment is expanding rapidly. While it is conceded that there probably have been no abrupt or profound instrumental breakthroughs in any of the areas discussed, the sum total of the advances being made in each of the cited areas, taken collectively, are impressive. It is quite evident that both the clinical and basic researcher now have at their command great quantities of equipment of excellent intrinsic quality that are appropriate for the types of assessment and research being carried out or contemplated. These devices are at a level of sophistication not dreamed of as little as 20 years ago. It is now necessary for the scientist and practitioner to exploit this wealth of facilities and to be prepared to utilize effectively the future instrumental advances that can be expected in this area.

Cineradiography↗
PubMedDate not supplied

Limb salvage surgery: an advance in surgical technique.

"Surgery is the primary and oldest treatment for malignant musculoskeletal tumors. Until the 1970's amputation was the accepted surgical procedure for patients with malignant tumors of the extremities. Recent advances in adjuvant treatment modalities such as chemotherapy and radiotherapy, bioengineering designs of internal prosthetic devices, radiographic workups, and bone and tissue transfers provide some individuals with the option of limb-preservation" (Lewis, 1992, p. 477-478). One limb salvaging technique uses a metallic implant to replace resected tumors of the bone. It is this surgical orthopaedic advancement that is currently being used in the resection of primary malignant bone tumors of the lower extremities at Mount Sinai Hospital, Toronto, Ontario. The objectives of this paper are to review the management of musculoskeletal tumors in "skeletally mature patients", and to review a system currently being utilized at Mount Sinai Hospital which provides a surgical option for resection and reconstruction of malignant bone tumors. The role the perioperative nurse plays in providing care to patients having limb salvage surgery will also be described. All three objectives will provide insight into the challenges facing orthopaedic oncology patients who are living with cancer.

Bone Neoplasms↗
PubMed1993

[Biomaterials based on collagen].

The review deals with collagen which is an essential natural polymer for preparing of biomaterials used in different fields of medicine. Besides discussing the structure of the basic polymer, the antigenicity of collagen materials as well as the bioactive properties of the collagen implants are described. The substantial part of the paper is oriented to the bioengineering processes of the preparation of the collagen matrix and composite structures. For these the physical and chemical modification of collagen are used. The processes of the modification are shown to be important in the fixing of the structure, improving the mechanical properties and influencing and directing the resorption of collagen materials in organism. Two types of materials are subdued to a detailed discussion. One which is combined with glycosoaminoglycanes and serves as the temporary skin cover and the second type, the structure of which, in the combination with hydroxylapatite imitates bone. (Tab. 4, Ref. 22.)

Animals↗
PubMed1994

Transesophageal echocardiography.

During the past ten years, two-dimensional echocardiography has become a major tool in the assessment of cardiovascular diseases. With the advent of pulsed, continuous wave, and color flow Doppler, the field of echocardiography is now accepted as the ideal noninvasive technique for assessing left and right ventricular function; determining valvular stenosis or regurgitation; assessing pericardial disease (i.e., constrictive pericarditis, pericardial effusion); determining diastolic dysfunction; estimating pulmonary artery pressures; examining for cardiac source of emboli; and evaluating for endocarditis. During the past five years, semi-invasive applications have included intracardiac echocardiography, guiding pericardiocentesis, assisting in percutaneous mitral valvotomy, catheter placement for ablation procedures, optimizing pacemaker hemodynamics, and using contrast agents to assess myocardial viability. With the miniaturization of transducers, bioengineers have developed probes small enough to be incorporated into the tip of a flexible gastroscope, thus accelerating the development of one of the most exciting and innovative techniques in cardiology, transesophageal echocardiography.

Cardiovascular Diseases↗
PubMed1994

[The pitfalls of the clearance concept in hemodialysis].

The "clearance concept" is rigorously defined by the physicists and bioengineers. However its extension in clinical routine of dialysis therapy is not easy, but essential also to understand the rationale on which is based the currently widely used Kt/V index. The purpose of this paper is to describe the difficulties and pitfalls encountered in measuring the clearance of a substance either provided by a dialyzer or observed in a dialyzed patient. Ambiguities in the definition of clearance may account for sometimes moot estimations of the Kt/V index.

Humans↗
PubMed1993

Myopic astigmatism and simple myopia correction.

A new technique for the treatment of myopic astigmatism and simple myopia correction is described. The technique is based on bioengineering concepts previously studied by the authors that accurately and mathematically describe the transformation of an ellipsoidal surface (astigmatic eye) into a spheroidal one (nonastigmatic eye) by means of minimal cuts (keratotomies). The surgical procedure is described using selected cases to illustrate the alternatives the model can handle. The model itself is not presented because the calculations were done by computer.

Adolescent↗
PubMed1993

Biomechanics and biology of fracture repair under external fixation.

The major factors determining the mechanical milieu of a healing fracture under external fixation, and thereby the mechanism of union, are the rigidity of the selected fixation device, the fracture configuration, the accuracy of fracture reduction, and the amount of physiologic stresses dictated by functional activity and loading. Bone healing problems encountered in fractures stabilized externally merely reflect the severity of the local soft-tissue and periosteal injury and should not be attributed to the inherent features of the fixation modality. Although some surgeons have had reservations concerning the use of external fixation for fracture treatment, based mainly on concerns of pin-tract infection and fracture nonunion, much of the clinical experience and basic science research results have proven the reverse. Many of the potential benefits of external fixation, such as the change of fixation stiffness, are not yet fully appreciated. Additional research and well-organized clinical trials must be performed. Pin-tract problems can be controlled, but the surgeon using such a device must be familiar with the techniques and follow the established regimens during postoperative care. One common mistake is to assume that external fixators, especially those of the simpler unilateral configuration, are easy to use and do not require learning or mastering the surgical techniques until the time of application. Periodic examination and radiographic evaluations are also essential to adjust conditions of the fracture site. The importance of balancing the biomechanical properties and the biologic consequences of different external fixation modalities has been demonstrated. Understanding this knowledge and the techniques of application associated with external fixation is the prerequisite to successful treatment. Some of the basic biomechanical information related to external fixation and bone fracture union is still unknown. This lack should provide the impetus for surgeons, bioengineers, and medical scientists to continue collaborative basic and applied research. Furthermore, by recognizing the proper cell mediators and the physical means to stimulate these cellular elements, the bone fracture healing process may be modulated, regardless of the fixation technique. The result of such effort should provide new modalities to improve fracture management.

Animals↗
PubMed1993

Is VXIbus for your biomedical measurement problem?

This paper will review the applicability of VXIbus based instruments to the needs of the bioengineering and biomedical measurement communities. Peak signal bandwidths supported by VXIbus extend to the GHz range which is well above most biological signal requirements. Similarly, environmental compatibility specifications including electromagnetic compatibility, cooling, shock, and vibration may exceed most needs and add to unnecessary cost. Despite these potential mismatches, the instrument-on-a-card and the virtual instrument capabilities of VXIbus offer advantages over existing RS-232, IEEE488.1/.2, plug-in cards, and other "rack-and-stack" systems. Expansion and flexibility inherent in VXIbus devices make them resistant to obsolescence and easy to upgrade. Users are faced with a number of selection criteria when making instrumentation decisions. Bandwidth, power, isolation, cost, performance, software for control, and future development needs are among the issues that must be evaluated. A list of systems, devices, and suppliers is provided as part of this paper.

Biomedical Engineering↗
PubMed1993

[Reliable and new aspects of insulin therapy].

New findings concerning the dynamic of insulin secretion, insulin action and pharmacokinetics of insulin preparations have caused a complete change of insulin therapy in diabetes mellitus (basis-bolus-concept). At the same time, the discrepancy between insulin substitution and physiologic conditions becomes evident. Even the use of human insulin or the development of insulin-pens and -pumps does not influence that fact. From the beginning of insulin therapy till now the subcutaneous injection of insulin is the safest and easiest way of application. By means of modified insulins (bioengineering) the physico-chemical process of insulin resorption could be elucidated in the last 4 years. In clinical experiments the intraperitoneal and nasal insulin administration is tested extensively. In the field of the intensified insulin therapy including near normoglycemic therapeutic goals the awareness of hypoglycemia is of particular importance.

Blood Glucose↗