The presence and activation of phenoloxidase in the blood of Ciona intestinalis and other ascidians was investigated in vitro. In C. intestinalis, phenoloxidase was found to exist in the cells as a proenzyme and to be activated by proteases. The microbial carbohydrates, LPS or laminarin, also enhanced enzyme activity but a similar effect was not achieved with other sugars. Calcium was not essential for enzyme activity and no enzyme suppression was seen at high calcium concentrations. Prophenoloxidase activation by LPS was further found to be dose related and inhibited by PTU and tropolone. Since benzamidine and STI reduced phenoloxidase activity in cell lysate supernatants, activation may involve other factors, possibly a serine protease. Lastly, as phenoloxidase activity was detected in the blood cells (usually the morula cells) of eight other ascidian species, it appears that it is widely distributed in the blood of this group of invertebrates.

Animals↗

PubMedDate not supplied

Dimensional accuracy of two denture base processing methods.

The mucosal surfaces of maxillary complete dentures processed using the SR-Ivocap injection technique and the Lucitone heat-polymerized compression molding technique were compared to a metal master impression to determine if one method of denture processing produced a more accurate denture base. Comparisons were made before and after polishing the prepared bases to determine if changes occur as a result of this procedure. The dental comparator, described by Rupp and others in 1957, was used to compare selected points on the palatal surface of the denture bases. No statistical differences were found in the accuracy of the denture bases processed using either of the two techniques.

Dental Casting Technique↗

PubMedDate not supplied

The influence of teeth on denture base processing accuracy.

The Michigan Computer Graphics Coordinate Measuring System was used to determine the influence of denture teeth on the accuracy of processed denture bases. Three different processing methods--compression molding, injection pressing, and vacuum-assisted resin pouring--were used. The presence of denture teeth was determined to affect the accuracy of the processed denture bases of all three techniques. For denture bases without teeth, the compression-molding technique demonstrated significant differences in accuracy; however, no significant differences were found in the injection-pressed or resin-poured denture bases.

Computer Graphics↗