Preparation of quadri-subtype influenza virus-like particles using bovine immunodeficiency virus gag protein.

Influenza VLPs comprised of hemagglutinin (HA), neuraminidase (NA), and matrix (M1) proteins have been previously used for immunological and virological studies. Here we demonstrated that influenza VLPs can be made in Sf9 cells by using the bovine immunodeficiency virus gag (Bgag) protein in place of M1. We showed that Bgag can be used to prepare VLPs for several influenza subtypes including H1N1 and H10N8. Furthermore, by using Bgag, we prepared quadri-subtype VLPs, which co-expressed within the VLP the four HA subtypes derived from avian-origin H5N1, H7N9, H9N2 and H10N8 viruses. VLPs showed hemagglutination and neuraminidase activities and reacted with specific antisera. The content and co-localization of each HA subtype within the quadri-subtype VLP were evaluated. Electron microscopy showed that Bgag-based VLPs resembled influenza virions with the diameter of 150-200nm. This is the first report of quadri-subtype design for influenza VLP and the use of Bgag for influenza VLP preparation.

Effect of repeated refrigerant spray applications using various carriers on pulpal temperature change.

This study sought to determine how repeated applications of a refrigerant spray on various cotton carriers affected the change in pulpal temperature. A thermocouple was placed at the roof of the pulp chamber of a human maxillary canine and connected to a thermometer logging at one-second intervals while the root was immersed in a water bath at 37 degrees C. Four different carrier types were used: large cotton pellets, small cotton pellets, cotton-tip applicators, and cotton rolls. Each carrier was sprayed with 1,1,1,2-tetrafluoroethane and placed on the crown for five seconds. Pulpal temperature change was recorded after each five second application of the same carrier to the tooth until a total of six consecutive sprays and applications of the carrier were applied. Each carrier group consisted of 10 performances of the six sets of readings (n = 10). The difference between baseline and the low temperature reading was calculated to determine the temperature change (in degrees C) in the pulp chamber per application. When the refrigerant spray was used, the large cotton pellet carrier generally produced the largest decrease in pulpal temperature at each repeated application compared to the other types of carriers. However, the same large cotton pellet should not be sprayed with the refrigerant more than two times before it is replaced.

Microtomographic porosity determination in alginate mixed with various methods.

PURPOSE: Mechanical spatulation of alginate impression materials reportedly produces fewer voids and superior casts than hand mixing. Two current methods of alginate mechanical preparation are a vacuum mixer Vac-U-Vestor, (Whip Mix Corp, Louisville, KY) and a semiautomated method that involves hand spatulation in a rotating bowl Alginator II (Cadco, Oxnard, CA). A new alginate-mixing machine has been introduced, TurboMax (Dentsply Raintree Essex, Sarasota, FL), with a centrifugal-spinning action that reportedly incorporates the alginate powder into the water more efficiently. The purpose of this study was to determine the number, percent, and volume distribution of porosities in alginate mixed with three mechanical-mixing methods using a nondestructive, microtomographic analysis method. MATERIALS AND METHODS: Alginate was mixed by each of the three mechanical methods per respective manufacturer's guidelines, with the set alginate analyzed using a microtomography unit and proprietary software. A mean and standard deviation was determined per group and analyzed with Kruskal-Wallis ANOVA/Mann-Whitney tests. RESULTS: Significant differences (p < 0.001) were found between groups per each of the three testing parameters (number, percent, volume distribution of porosities). The vacuum mixer produced significantly less percent porosity and number of porosities than the centrifugal mixer and semiautomated hand mixer. Both the vacuum mixer and centrifugal mixer produced porosities of significantly smaller volume than the semiautomated hand mixer. CONCLUSION: Of the three mechanical mixing methods, the vacuum mixer had the best performance overall in reducing the number, percent, and volume of porosities in the mixed alginate.