The purposes of this study were to evaluate the effects on cell growth and migration of fibroblasts derived from human dental pulp by lasers using three-dimensional (3-D) cell culture system, and to compare the results with those from conventional methods using a two-dimensional (2-D) cell culture system. After extirpation from twenty freshly extracted human third molars showing no clinical sign of caries, pulp tissues were cultured in Minimum Essential Medium using a conventional 2-D cell culture. The cells between 5 and 18 passages were used for this experiment, and collagen gel (1 mg/ml) was used for the 3-D cell culture system. The energy densities used were 0.52 and 1.04 J/cm2 for the gallium aluminum arsenide (GaA1As) diode laser emitting at 830 nm, and 0.1 and 1.0 J/cm2 for the argon (Ar)-dye laser emitting at 632 nm. After laser irradiation, cells were counted at 2, 4, 6, and 8 days, and observed at 3 days by stereomicroscopy. There was no significant difference in cell count between the control groups and the laser-irradiated groups (both lasers) on any day using the 2-D cell culture system (p > 0.01). However, there were significant differences in cell count between the control groups and the laser-irradiated groups (both lasers) at 8 days using the 3-D cell culture (p < 0.01). Cell migration appeared more accelerated by laser in 3-D cell culture than in the 2-D system. These results suggest that the 3-D cell culture system is useful for the evaluation of potential stimulative effects of lasers.

A recent hypothesis postulated that paleoclimate changes to the Southern Hemisphere westerlies were characterized by the modulation of the wintertime South Pacific Split Jet. We explore this hypothesis further through simulating changes to the ocean circulation from Split Jet modulation, contrasting them against changes associated with the wintertime Southern Annular Mode (SAM). Three responses distinguish the Split Jet from the SAM impact on ocean circulation. (i) A weaker Split Jet strengthens the South Pacific subtropical gyre, leading to stronger western boundary currents and warming of the sea surface temperatures (SSTs) surrounding New Zealand. (ii) A positive SAM leads to an increase in the Antarctic Circumpolar Current and specifically Drake Passage throughflow. And (iii) a weaker Split Jet leads to increased formation of Subantartic Mode Water, whereas a positive SAM leads to increased Antarctic Intermediate Water. Both a weaker Split Jet and positive SAM lead to increased Southern Ocean meridional overturning circulation, though it is more pronounced for the latter. However, enhanced ventilation of deep water in both cases increases atmospheric pCO2 by only 1–3 ppm, because the associated cooling and efficient nutrient utilization in the model effectively negates the venting of deep ocean carbon. Both a weaker Split Jet and positive SAM enhance oxygenation of the deep ocean and intermediate waters but diminish oxygenation of the eastern equatorial Pacific. Our results provide guidance to distinguish SAM-like changes from Split Jet-like changes in paleoceanographic records, and we discuss the case of early deglacial transition to Heinrich 1.

The effects of nanosecond pulsed Nd:YAG irradiation on crown and root dentin susceptibility to artificial de- and remineralization were investigated. Laser-induced heating and structural effects were also determined. Thirty caries-free extracted human molar teeth were used. One group of 12 teeth was bisected longitudinally, and each surface covered with acid resistant varnish, leaving 4 windows on the cut dentin surface. Using a Q-switched nanosecond pulsed Nd:YAG laser (1064 nm), one half of each tooth was irradiated at one of the following parameters: 3 mm spot size, a fluence of 1.0 J/cm2. The other half of each tooth served as (non-irradiated) control. All samples were then subjected to a 4 day, thrice daily de- and remineralization cycle. Prior to and after each demineralization, microhardness measurements were taken. After 4 days, samples were again bisected, and the other sample halves used for SEM. Microhardness in the irradiated samples did not differ significantly (p < 0.01) compared with controls; SEM results showed some laser-induced alterations on crown and root dentin surfaces. Thermometric measurements on 18 teeth at energy densities of 1.0-4.1 J/cm2 revealed intrapulpal temperature increases of approximately 2°C at a dentin thickness of 2 mm during irradiation. No consistent effect of Q-switched nanosecond pulsed Nd:YAG laser irradiation on microstructure and de- and remineralization of dentin was determined (p < 0.01). but SEM results showed some surface alterations on the irradiated samples.

We have previously reported that T cells bearing T cell receptors (TCRs) of gamma/delta type appear at a relatively early stage of primary infection with Listeria monocytogenes in mice. To characterize the early-appearing gamma/delta T cells during listeriosis, we analyzed the specificity and cytokine production of the gamma/delta T cells in the peritoneal cavity in mice inoculated intraperitoneally with a sublethal dose of L. monocytogenes. The early-appearing gamma/delta T cells, most of which were of CD4-CD8- phenotype, proliferated and secreted IFN-gamma and macrophage chemotactic factor in response to purified protein derivative from Mycobacterium tuberculosis, or recombinant 65-kD heat-shock protein derived from M. bovis but not to heat-killed Listeria. To further elucidate the potential role of the gamma/delta T cells in the host-defense mechanism against primary infection with Listeria, we examined the effects of in vivo administration of monoclonal antibodies (mAbs) against TCR-gamma/delta or TCR-alpha/beta on the bacterial eradication in mice infected with Listeria. Most of alpha/beta T cells or gamma/delta T cells were depleted in the peripheral lymphoid organs at least for 12 d after an intraperitoneal injection of 200 micrograms TCR-alpha/beta mAb or 200 micrograms TCR-gamma/delta mAb, respectively. An exaggerated bacterial multiplication was evident at the early stage of listerial infection in the gamma/delta T cells-depleted mice, whereas the alpha/beta T cell-depleted mice exhibited much the same resistance level as the control mice at this stage although the resistance was severely impaired at the late stage after listerial infection.(ABSTRACT TRUNCATED AT 250 WORDS)

In this study, sound and carious dentin slices were visualized using a fluorescence technique and confocal laser scanning microscopy (CLSM). Twenty extracted human molar teeth showing no clinical signs of caries, and thirty additional teeth with pre-existing naturally occurring dentin caries were investigated. All teeth were horizontally sectioned to approximately 200 μm thickness and in forty sound sections from ten teeth, artificial caries-like lesions were induced for 3 days. All sections were pretreated with 5.25% sodium hypochlorite, vacuum and ultrasonication for one hour, then stained with Rhodamine 123 fluorescent dye at a concentration of 10-5 M in phosphate buffer saline for 3 h. Surface and subsurface images obtained using CLSM showed dentinal tubules in sound dentin and in artificial caries-like lesions which usually appeared open. Most dentinal tubules in carious dentin appeared obturated or narrowed. Thus, non-invasive surface and subsurface imaging of dentin structures is possible and useful using confocal laser microscope techniques, without the problematic invasive preparations required for scanning electron microscopy (SEM).