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Oligodeoxynucleotide Probes for Detecting Intact Cells

Cells can be detected, identified, and enumerated via chemiluminescence. A rapid, sensitive test using chemiluminescent oligodeoxynucleotide probes has been developed for detecting, identifying, and enumerating intact cells. The test is intended especially for use in detecting and enumerating bacteria and yeasts in potable water.

Posted in: Medical, Briefs

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Using an Ultrasonic Instrument to Size Extravascular Bubbles

Measurements could be used to guide prebreathing of oxygen to reduce the risk of decompression sickness. In an ongoing development project, microscopic bubbles in extravascular tissue in a human body will be detected by use of an enhanced version of the apparatus described in "Ultrasonic Bubble- Sizing Instrument" (MSC-22980), NASA Tech Briefs, Vol.24, No.10 (October 2000), page 62. To recapitulate: The physical basis of the instrument is the use of ultrasound to excite and measure the resonant behavior (oscillatory ex- pansion and contraction) of bubbles. The resonant behavior is a function of the bubble diameter; the instrument exploits the diameter dependence of the resonance frequency and the general nonlinearity of the ultrasonic response of bubbles to detect bubbles and potentially measure their diameters.

Posted in: Bio-Medical, Medical, Briefs

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Transplanting Retinal Cells Using Bucky Paper for Support

Bucky paper supports the cells before, during,and after surgery. A novel treatment for retinal degenerative disorders involving transplantation of cells into the eye is currently under development at NASA Ames Research Center and Stanford University School of Medicine. The technique uses bucky paper as a support material for retinal pigment epithelial (RPE) cells, iris pigment epithelial (IPE) cells, and/or stem cells. This technology is envisioned as a treatment for age-related macular degeneration, which is the leading cause of blindness in persons over age 65 in Western nations. Additionally, patients with other retinal degenerative disorders, such as retinitis pigmentosa, may be treated by this strategy. Bucky paper is a mesh of carbon nanotubes (CNTs), as shown in Figure 1, that can be made from any of the commercial sources of CNTs. Bucky paper is biocompatible and capable of supporting the growth of biological cells. Because bucky paper is highly porous, nutrients, oxygen, carbon dioxide, and waste can readily diffuse through it. The thickness, density, and porosity of bucky paper can be tailored in manufacturing. For transplantation of cells into the retina, bucky paper serves simultaneously as a substrate for cell growth and as a barrier for new blood vessel formation, which can be a problem in the exudative type of macular degeneration. Bucky paper is easily handled during surgical implantation into the eye. Through appropriate choice of manufacturing processes,bucky paper can be made relatively rigid yet able to conform to the retina when the bucky paper is implanted. Bucky paper offers a distinct a vantage over other materials that have been investigated for retinal cell transplantation — lens capsule and Descemet's membrane — which are difficult to handle during surgery because they are flimsy and do not stay flat. In preparation for implantation, the selected cells are first cultured onto a piece of bucky paper.

Posted in: Medical, Briefs, TSP

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FEA Software Enables Study of Tissue Ablation Dynamics

An improved ablation device model uses a feedback loop to account for varying properties of heated or damaged tissue. Regulatory agencies such as the US FDA must examine new medical devices to ensure that they are safe and effective. Sometimes, devices work successfully despite the fact that the mechanism of how they work isn't fully understood. In these cases, the FDA performs basic research to fill in these knowledge gaps.

Posted in: Medical, Briefs

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Finite Element Analysis Used to Examine the Healing of Animal Bones

The effectiveness of using stabilization pins and external skeletal fixators was determined by FEA analysis. When a dog or cat breaks a bone, veterinarians often mend the fracture with a combination of stabilization devices called intra-medullary (IM) pins and external skeletal fixators (ESFs), a technique that is employed daily across the U.S. Research conducted at the University of Georgia under the direction of Dennis Aron, DVM, using ALGOR finite element analysis software, is helping to establish better guidelines for how these stabilization devices can best be used to promote healing of animal fractures.

Posted in: Medical, Briefs

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Multisensor Instrument for Real-Time Biological Monitoring

Multiple parameters can be measured simultaneously by use of a single compact sensor head. The figure schematically depicts an instrumentation system, called a "fiber optic-based integration system" (FOBIS), that is undergoing development to enable real-time monitoring of fluid cell cultures, bioprocess flows, and the like. The FOBIS design combines a micro flow cytometer (MFC), a microphotometer (MP), and a fluorescence-spectrum- or binding-force-measuring micro-sensor (MS) in a single instrument that is capable of measuring multiple biological parameters simultaneously or sequentially. The fiber-optic-based integration system is so named because the MFC, the MP, and the MS are integrated into a single optical system that is coupled to light sources and photometric equipment via optical fibers. The optical coupling components also include a wavelength-division multiplexer and diffractive optical elements. The FOBIS includes a laser-diode- and fiber-optic-based optical trapping subsystem ("optical tweezers") with microphotometric and micro-sensing capabilities for noninvasive confinement and optical measurement of relevant parameters of a single cell or other particle.

Posted in: Bio-Medical, Medical, Briefs, TSP

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Spore-Forming Bacteria That Resist Sterilization

A report presents a phenotypic and genotypic characterization of a bacterial species that has been found to be of the genus Bacillus and has been tentatively named B. odysseensis because it was isolated from surfaces of the Mars Odyssey spacecraft as part of continuing research on techniques for sterilizing spacecraft to prevent contamination of remote planets by terrestrial species. B. odysseensis is a Gram-positive, facultatively anaerobic, rod-shaped bacterium that forms round spores. The exosporium has been conjectured to play a role in the elevated resistance to sterilization. Research on the exosporium is proposed as a path toward improved means of sterilization, medical treatment, and prevention of biofouling.

Posted in: Medical, Briefs, TSP

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