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Biomedical subjects

P L Stewart

Publications and source records attributed to P L Stewart.

8 recordsLinked to original sources
PubMed1991

Image reconstruction reveals the complex molecular organization of adenovirus.

The three-dimensional structure of adenovirus has been determined by image reconstruction from cryo-electron micrographs. Comparison with the high resolution X-ray crystal structure of hexon, the major capsid protein, enabled an unusually detailed interpretation of the density map and confirmed the validity of the reconstruction. The hexon packing in the capsid shows more extensive intermolecular interfaces between facets than previously proposed. The reconstruction provides the first three-dimensional visualization of the vertex proteins, including the penton base and its associated protruding fiber. Three minor capsid proteins that stabilize and modulate capsomer interactions are revealed. One of these components stabilizes the group-of-nine hexons in the center of each facet and the other two bridge hexons in adjacent facets. The strategic positions of these proteins highlight the importance of cementing proteins in stabilizing a complex assembly.

Adenoviruses, Human↗
PubMed1989

Instant slides of radiographs for lectures.

High quality slides of radiographs may be made with a simple, fast, and inexpensive technique using Kodak Rapid Process Copy film. Lecture presentations may include a slide of a pertinent plain radiograph, computed tomography (CT) scan, or magnetic resonance imaging (MRI). Although these slides may be made with a 35 mm SLR camera and flash or with a 35 mm SLR camera and a lighted viewbox, an alternative method is available that is easy to perform, inexpensive, and can produce quality slides in as little as 30 minutes.

Audiovisual Aids↗
PubMed1987

The toxicity of phomopsin for sheep.

Pure phomopsin was administered to young Merino x Border Leicester wethers by single subcutaneous (SC) and by single and multiple intraruminal (IR) injection. The toxicity after IR injection was influenced by the size of individual doses and the time over which the total dose was given. At high levels of ingestion the toxicity of phomopsin may be limited by absorption rates; with low daily doses the capacity to repair liver damage may be sufficient to prevent cumulative effects. By SC injection a single dose of 10 micrograms/kg approximated the LD50. By IR injection the overall clinical, biochemical and histological responses closest to these of this SC dose resulted from a single dose of 1,000 micrograms/kg. The same total dose administered at daily rates of 50 or 200 micrograms/kg was more toxic and killed all sheep. A single dose of 500 micrograms/kg caused significant liver damage, but no deaths. Single doses of 125 and 250 micrograms/kg and repeated daily doses of 12.5 micrograms/kg over 16 weeks caused no detectable tissue damage. Inappetence was the most sensitive indicator of phomopsin toxicity. About 10% of the sheep differed substantially from the rest of the flock in their susceptibility to phomopsin poisoning.

Administration, Oral↗
PubMed1978

A survey of obstetrician-gynecologists' abortion attitudes and performances.

Attitudes toward general and repeat abortion are examined in a probability sample of board certified obstetrician-gynecologists in three Mid-Atlantic states. A mail-back questionnaire yielded seventy per cent response rate. A typology of abortion attitudes was developed by combining scores on two Guttman scales, one general acceptance and one repeat abortion acceptance scale. This resulted in six types varying from conservative to liberal. Personal and work setting characteristics were examined as correlates of abortion attitude. Personal characteristics are correlated; work setting characteristics are not. Obstetrician-gynecologists; abortion attitudes and performances are related.

Abortion, Legal↗
PubMed1975

Method development and subsequent survey analysis of biological tissues for platinum, lead, and manganese content.

An emission spectrochemical method is described for the determination of trace quantities of platinum, lead, and manganese in biological tissues. Total energy burns in an argon-oxygen atmosphere are employed. Sample preparation, conditions of analysis, and preparation of standards are discussed. The precision of the method is consistently better than +/- 15%, and comparative analyses indicate comparable accuracies. Data obtained for experimental rat tissues and for selected autopsy tissues are presented.

Animals↗