Medical

Precision Targeting with a Tracking Adaptive Optics Scanning Laser Ophthalmoscope

Adaptive optics (AO) has become increasingly utilized in research ophthalmic diagnostic instruments since their first use nearly ten years ago. Integration of adaptive optics in scanning laser ophthalmoscopy (SLO) is a flying-spot technique whereby scattered light in images is blocked by placement of an aperture at a back conjugate focal plane. Adaptive optics systems sense perturbations in the detected wavefront and apply corrections to an optical element that flattens the wavefront and allows near diffraction-limited focus.

Posted in: Briefs, Medical, Adaptive control, Lasers, Medical equipment and supplies
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High-Resolution Anatomic and Elastographic Transrectal Ultrasound for Improved Diagnosis of Prostate Cancer

Prostate cancer screening generally uses the Pro state Spe cific Antigen (PSA) blood test, free-PSA testing, and Digital Rectal Exam ination (DRE). When the PSA is used, there exists a significant gray area in which cancers may be missed. Addition ally, DRE is practically limited to the detection of shallow (subcapsular) palpable abnormalities. Even systematic multi-core biopsy fails to detect clinically detectable cancers in up to 34% of men. Thus, there is compelling clinical interest in finding improved detection methods.

Posted in: Briefs, Medical, Diagnosis, Diseases, Physical examination, Acoustics, Test equipment and instrumentation
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Macromolecular Carriers for Nanomedicine and Nano Devices

Tailoring the surface properties of biodegradable nanospheres and microspheres for in-vivo blood-contacting applications includes defining relationships among chemical composition, processing parameters, nanosphere sizes and size distributions, and surface structure. Developments include: 1) a facile method for achieving magnetite-polylactide nanospheres that can be dispersed in aqueous media; 2) methods for functionalizing the termini of the hydrophilic brushes on the nanospheres in order to conjugate targeting moieties; 3) development of a nanosphere processing approach that yields nanospheres in the desired size range with a narrow distribution of sizes; and 4) maintainence of all of these characteristics with up to approximately 60 weight percent of magnetite incorporated into the nanospheres.

Posted in: Briefs, Medical
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Genetic Studies of Responses of Bones to Mechanical Stresses

Progress has been reported in a continuing program of molecular genetic studies of the responses of bones to mechanical stresses. Prior studies in mice and humans had provided evidence that mechanical loading stimulates bone formation and that immobilization or loss of mechanical stimulation leads to decreasing bone formation and increasing bone loss. Other prior studies in humans and mice had demonstrated that bone anabolic response differs widely among individuals subjected to the same degree of mechanical loading. The initiation of the present studies was motivated by the conjecture that variations in bone anabolic response among individuals are attributable to differences in the transcription levels of genes; that is, they are genetically controlled.

Posted in: Briefs, Medical
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Tactical Medical Coordination System

The term “tactical medical coordination system” (TacMedCS) denotes any of several prototype electronic systems for tracking patients in a scenario that may involve multiple instances of treatment by different medical personnel in different locations. The TacMedCS was conceived as a means of facilitating coordination of care of military personnel injured in combat and/or facilitating coordination of care of victims of large-scale disasters. The most advanced prototype has already been demonstrated to be effective in operations at a Navy fleet hospital.

Posted in: Briefs, Medical
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Remote Blood Pressure Waveform Sensing

This non-contact, non-invasive blood pressure apparatus continuously measures and monitors blood pressure using a laser Doppler vibrometer to create waveforms. The laser-based system may be utilized to continuously provide highly detailed information about the timing characteristics of the blood pressure waveform. The system does not require elaborate adjustments of one or more lasers and laser detectors so it may be quickly utilized. The system takes measurements from a subject when the subject is moving.

Posted in: Briefs, Medical
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NO-Generating Coats for Subcutaneous Glucose Sensors

In a research program now in progress, polymeric materials that catalyze the generation of nitric oxide (NO) at low concentrations are being developed and tested for utility as coatings on surgically implantable amperometric glucose sensors. Heretofore, efforts to develop subcutaneous sensors for real-time clinical monitoring of glucose concentrations in diabetic patients have been stymied by inflammatory/foreign-body responses to implantation of sensors. The present research program follows from an observation, made in a related prior research program, that local generation of NO at low concentrations enhances the biocompatibility of implanted sensors by reducing inflammatory responses.

Posted in: Briefs, Medical, Sensors and actuators, Nitrogen oxides, Prostheses and implants, Coatings Colorants and Finishes
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Update on Implantable Sensors for Metabolic Monitoring

Progress has been made in a continuing effort to develop surgically implantable, biocompatible electrochemical- sensor arrays for continuous measurement of concentrations of analytes that play major roles in human and animal metabolism. This development at an earlier stage was described in “Implantable Electrochemical Sensors for Metabolic Monitoring” (ARL-0017), Defense Tech Briefs, Vol. 1, No. 4 (August 2007), page 28. To recapitulate: in the electrochemical-monitoring approach followed in this development effort, cyclic voltammetry, amperometry, squarewave voltammetry, or a combination of these techniques is used to measure the rate of catalytic oxidation of glucose by the enzyme glucose oxidase (GOX) in a reaction mediated by poly[vinyl pyridine Os(bipyridine)2Cl]- co-ethylamine (POs- EA), which is an osmium-based polycationic redox polymer. To ensure biocompatibility, the GOX is entrapped in a poly(ethylene glycol) diacrylate (PEGDA) hydrogel that has previously been demonstrated to be biocompatible.

Posted in: Briefs, Medical, Architecture, Biological sciences, Prostheses and implants, Polymers
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Toward High-Performance Neural Control of Prosthetic Devices

A program of basic and applied research in neuroscience is dedicated to (1) advancing fundamental understanding of how the human brain plans and executes arm movements and (2) designing and building high-performance neural prostheses for controlling arm prostheses. The basic-research part of the program involves experiments on non-human primates by use of techniques of chronic-electrode-array electrophysiology, computational neuroscience, theoretical neuroscience, and observations of reaching behavior. The appliedresearch part of the program includes, as part of the effort to develop neural prostheses, an effort to decode (that is, to extract scientifically and prosthetically useful signals from) neural activity in real time, use the signals generated in the decoding process to move computer cursors, and utilize the knowledge thus gained to design and validate high-performance neural-prosthetic algorithms.

Posted in: Briefs, Medical, Mathematical models, Nervous system, Prostheses and implants, Biomechanics
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Progress Toward Cell-Directed Assembly of Nanostructures

During 2007, progress was made on several fronts in a research program oriented toward developing capabilities for biocompatible and biomimetic self-assembly of nanostructures that could perform desired functions as interfaces between biological and nanotechnological systems (“bio/nano” interfaces). These capabilities are expected to contribute, in turn, to development of new classes of biotic/abiotic materials and to understanding of responses of cells to diseases, injuries, stresses, and therapies. The approach followed in this research has been one of striving to understand and exploit celldirected assembly (CDA).

Posted in: Briefs, Medical, Research and development, Assembling, Biomaterials, Nanotechnology
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