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Biomedical subjects

R S Nelson

Publications and source records attributed to R S Nelson.

108 records · Page 6Linked to original sources

A controlled endoscopic study comparing the toxic effects of sulindac, naproxen, aspirin, and placebo on the gastric mucosa of health volunteers.

Sixty volunteers were endoscopically evaluated to compare gastric mucosal injury following oral administration of sulindac, naproxen, aspirin, or placebo for two consecutive seven-day periods. A single-blind technique was utilized wherein the endoscopist was unaware which drug each volunteer had received. The following dosages were employed for the two study periods: sulindac, 150 and 200 mg, b.i.d., naproxen, 250 and 375 mg, b.i.d., and aspirin, 650 and 975 mg, q.i.d. The only subject who developed a frank ulcer with mucosal bleeding was in the sulindac group, however volunteers taking sulindac demonstrated statistically less significant mucosal injury on endoscopic examination than those receiving naproxen or aspirin.

Adult↗

Characterization of the masked strain of tobacco mosaic virus: identification of the region responsible for symptom attenuation by analysis of an infectious cDNA clone.

A strain of tobacco mosaic virus (TMV) that produces mild (attenuated) symptoms on tobacco plants has been molecularly cloned to identify the region of the genome responsible for symptom attenuation. A full-length cDNA clone whose transcripts produce the parental disease phenotype on both systemic and hypersensitive host plants has been constructed. This infectious clone was sequenced, and 55 base changes relative to the published sequence of common TMV (strain U1) were identified. These changes resulted in 12 amino acid alterations in the open reading frames encoding the 126/183-kDa and 30-kDa movement proteins; two of these changes were determined not to be responsible for the attenuated phenotype. Exchange of restriction fragments between the infectious mild strain cDNA and an infectious U1 strain cDNA indicated that the determinants involved in symptom attenuation reside in the open reading frame encoding the 126/183-kDa proteins of TMV; these proteins are involved in viral replication.

Base Sequence↗

An evaluation of a fluorescent screen-isocon camera system for x-ray imaging in radiology.

A large field format imaging system which utilizes a flat fluorescent screen rather than the traditional image intensifier as the primary x-ray detector is discussed in this paper. A low light level image isocon camera is optically coupled to a rare-earth screen. An overview of the isocon camera and its return beam mode of operation is included. Theoretical limitations to this approach to real time radiographic imaging are discussed in terms of system efficiency and signal-to-noise ratio (SNR) requirements. The viability of this concept for radiographic imaging is considered with respect to the image intensifier-camera unit. The merits of employing a CsI:Na screen as the primary detector and an isocon tube with an improved SNR are presented as potential areas for further investigation.

Evaluation Studies as Topic↗

A double-blind randomized placebo controlled gastroscopic study to compare the effects of indomethacin capsules and indomethacin suppositories on the gastric mucosa of human volunteers.

Forty-five normal volunteers were divided into 3 equal groups, each receiving indomethacin or placebo once daily in he evening as a capsule or suppository for 10 days. The dose of indomethacin was 50 mg for the first 5 days and 100 mg for the second 5 days. Endoscopic evaluation of the gastric mucosa was carried out on days 1, 6 and 11. It was found that indomethacin capsules caused significantly more gastric irritation than indomethacin suppositories (p less than .01) or placebo (p less than .0001). No significant difference was found in the incidence of gastric injury observed in the indomethacin suppository and placebo groups.

Administration, Oral↗