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P Person

Publications and source records attributed to P Person.

47 records · Page 3Linked to original sources
PubMedDate not supplied

A microprocessor temperature-controlled air delivery system for dentinal hypersensitivity testing.

A new microprocessor temperature controlled air delivery system for determining cold and warm temperature thresholds of dentinal hypersensitivity has been designed and built. The temperature range of the unit is -5 degrees to + 85 degrees C. Air is delivered from a typical dental unit air syringe nozzle at a relatively gentle flow rate of 0.2 cu ft/min at operator selected temperatures, with an accuracy of +/- 0.2 degrees C. Within seconds, 1 degree to 5 degrees temperature increments or decrements are accomplished. Larger, i.e., 20 degree increments or decrements, require approximately 15 seconds. The unit can operate from standard 110 V/60 Hz or 230 V/50 Hz outlets and requires a source of compressed air at 60 psig, equivalent to that provided by dental operatory-type air compressors. This report provides a description of the unit, its operation, and data from two clinical studies in which it was used successfully to determine temperature thresholds of dentinal hypersensitivity.

Dentin Sensitivity↗
PubMedDate not supplied

Development of chick limb bud chondrocytes in cell culture: morphologic and oxidative metabolic observations.

For the purpose of describing early chondrogenic metabolic and structural events, measurements were made of oxidative and other enzymatic activities at various stages in the morphologic development of chondrocytes over a period of 18 to 20 days in continuous cell culture. Comparisons were also made between cells grown in 20% O2 and in 35% O2. These cultures exhibited rapid confluence (within 24 hours), early development of cartilaginous nodules by Day 2 to 3 and metachromatic staining of the chondrocyte matrix by Day 3 to 4. Under 35% O2, cell sheets were thicker and there was increased pleomorphism of chondrocyte and fibroblast cell types, with a relative increase of fibroblast components and reduction in chondroblasts and chondrocyte aggregates. Using the von Kossa staining procedure, calcium salt deposition was observed by Day 9. There was no apparent difference in mineralization of cultures grown under the low and high O2 tensions. Under normoxic conditions cytochrome oxidase and malate dehydrogenase (MDH) activities increased rapidly for the first three to four days and then remained essentially constant. Lactate dehydrogenase (LDH) activity increased continuously over the life of the culture. Acid phosphatase increased rapidly until about Day 13 after which it remained constant, whereas alkaline phosphatase showed a bimodal activity profile. Under hyperoxic conditions, cytochrome oxidase, MDH and alkaline phosphatase activity were significantly inhibited. LDH and acid phosphatase activities were markedly inhibited initially but with time showed a degree of recovery.

Animals↗