Biomedical subjects
Publications and source records attributed to D L Stoner.
We report the development of a prototype database that "maps" microbial diversity in the context of the geochemical and geological environment and geographic location. When it is fully implemented, scientists will be able to conduct database searches, construct maps containing the information of interest, download files, and enter data over the Internet.
A fluorescence-labeled wheat germ agglutinin staining technique (R. K. Sizemore et al., Appl. Environ. Microbiol. 56:2245-2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure.
Microbial communities in water from Baltimore Harbor and from the mainstem of Chesapeake Bay were examined for sensitivity to mercuric chloride, monomethyl mercury, stannic chloride, and tributyltin chloride. Acute toxicity was determined by measuring the effects of [3H]thymidine incorporation, [14C]glutamate incorporation and respiration, and viability as compared with those of controls. Minimum inhibitory concentrations were low for all metals (monomethyl mercury, less than 0.05 microgram liter-1; mercuric chloride, less than 1 microgram liter-1; tributyltin chloride, less than 5 micrograms liter-1) except stannic chloride (5 mg liter-1). In some cases, mercuric chloride and monomethyl mercury were equally toxic at comparable concentrations. The Chesapeake Bay community appeared to be slightly more sensitive to metal stress than the Baltimore Harbor community, but this was not true for all treatments or assays. For culturable bacteria the opposite result was found. Thymidine incorporation and glutamate metabolism were much more sensitive indicators of metal toxicity than was viability. To our knowledge, this is the first use of the thymidine incorporation method for ecotoxicology studies. We found it the easiest and fastest of the three methods; it is at least equal in sensitivity to metabolic measurements, and it likely measures the effects on greater portion of the natural community.
The supportive properties of polyurethane foam wheelchair cushions change significantly during the first hours of use. Thus, cushions which initially appear to optimally distribute the patient's weight may not do so after a break-in period. To solve this problem, a cushion prestressing protocol has been devised which breaks-in the foam cushion prior to determination of the patient's pressure distribution. It was found that the useful life of these cushions is adversely affected by heavy static loading and high temperatures, and if allowed to rest, polyurethane foam cushions recover a portion of their original load-bearing properties.
A preliminary model was prepared for the development of superficial burns which can result from the interaction of faulty defibrillator and other electrical operating room equipment. A thermal model previously used to predict retinal coagulation was adapted to give temperature rise history of the skin. Skin resistance is assumed to decrease rapidly due to the instability of a small volume near the surface. Heating due to dissipation of the defibrillator capacitor energy in this skin volume is shown to be high enough to cause burns. A sensitivity analysis is included to isolate the dominant input parameters. Recommendations are made for future research.
The attachment of various types of electronic instrumentation to a patient can lead to hazardous interactions. Component malfunction in a single piece of equipment connected to a patient may be totally innocuous. However, the same fault occurring in an identical piece of equipment functioning as one component in a network of monitoring and electrosurgical equipment can result in severe burns or even electrocution. This paper describes interaction between a defective defibrillator paddle and an electrosurgical unit. Burns and ventricular fibrillation resulting from this malfunction and interaction are described in detail and the electrical circuits are analyzed.
A case is presented and electrochemical theory is discussed in a situation in which a battery was produced between two dissimilar metals in a Finochietto rib spreader. The problem developed in the thorax of a patient undergoing transthoracic cervical sympathectomy and resection of the first rib. Caution is advised in the use of dissimilar metals in patients undergoing surgery.
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In the past, the only acceptable method for protecting hospital patients against the hazards of macroshock and microshock was equipotential grounding: a system whereby potential differences between conductive surfaces are minimized, and ground loops are eliminated, through use of a network of grounding conductors connected in a tree-branch configuration to a common reference point. Experience at a major medical facility involving attempts to create and maintain an equipotential grounding system has proven this method to be costly, impractical, and potentially hazardous. Recent improvements in the input circuitry of medical instrumentation and the rapid disappearance of explosive anesthetics from many hospital inventories now make it possible to suggest an alternative approach to electrical safety: the insulated environment.
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Explore the source record for details and available documents.