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Biomedical subjects

P L Lowry

Publications and source records attributed to P L Lowry.

5 recordsLinked to original sources
PubMed1985

Skeletal alterations in ovariectomized rats.

Female Sprague Dawley rats were subjected to either bilateral ovariectomy or sham surgery. Tetracycline derivatives were administered to each rat on two separate occasions to label sites of bone formation. All rats were sacrificed at 5 weeks postovariectomy and their proximal tibiae were processed undecalcified for quantitative bone histomorphometry. A twofold decrease in trabecular bone volume was noted in the proximal tibial metaphysis of ovariectomized rats. This bone loss was associated with elevated histomorphometric indices of bone resorption and formation. Ovariectomy increased osteoclast surface and numbers as well as osteoblast surface and numbers. Elevations in calcification rate and fractional trabecular bone surface with double tetracycline labels also suggest that bone formation was stimulated in ovariectomized rats. In addition, ovariectomized rats exhibited a greater rate of longitudinal bone growth relative to sham-operated control rats. These histomorphometric data indicate that ovariectomy induces marked bone loss and accelerated skeletal metabolism in rats.

Animals↗
PubMed1979

Quantitative fit-test method for powered air-purifying respirators.

The fit-test method for powered air-purifying respirators described here allowed quantitative determination of the leakage of PAPRs that offered PFs ranging from 50 to greater than 10,000. Five types of PAPRs were tested on 10 subjects selected from a test panel representing a wide range of facial sizes. PAPRs tested provided all subjects with PFs of 1000 or greater when operated with the blowers on, while PFs observed with the blower off, for two tight-fitting facepieces, ranged between 50 and 100. The exercises used in these test procedures are believed to be typical of movements made by persons wearing respiratory protective equipment and performing light work. Studies of PFs obtained by workers wearing respiratory protective equipment in industry would be necessary to establish how well the developed laboratory test methods predict the level of protection offered to workers wearing the equipment.

Female↗
PubMed1978

Comparison of a sodium chloride aerosol filter test method to silica-dust and silica-mist filter test methods.

A LASL-developed sodium chloride aerosol filter penetration test has been compared to the silica-dust and silica-mist tests used by NIOSH for respirator approval testing. Filter discs were made from two types of resin impregnated electrostatic felt filter materials and tested at LASL for resistance to air flow and sodium chloride aerosol penetration. Sets of these filters were sent to four respirator manufacturing companies, where silica-dust and silica-mist penetration tests were performed. One set of filters was sent to NIOSH Division of Physical Sciences and Engineering in Cincinnati where sodium chloride aerosol penetration tests were performed by NIOSH personnel.

Aerosols↗
PubMed1977

Performance of single-use respirators.

Six models of single-use dust respirators were evaluated for NaCl aerosol leakage while being worn by human test subjects. The respirators were evaluated for their ability to fit a wide range of facial sizes, for changes in efficiency after storage in a humid atmosphere; and for consistency of protection when worn for a six-hour work shift. Results indicate that only two of the six models tested provided a protection factor of 5 to all members of a 10 person test panel. Storage in a humid atmosphere had no detectable effect on five of the models, while one showed a decrease in the level of protection offered. Throughout a 6 hour work shift, four of the six models provided a consistent level of protection, while two showed variations in the level of protection offered.

Air Pollutants, Occupational↗