The ocular microenvironment has evolutionarily adapted several mechanisms of immunosuppression to minimize the induction of inflammation. Neuropeptides produced by the retinal pigment epithelial cells regulate macrophage activity. Two neuropeptides, α-melanocyte–stimulating hormone (α -MSH) and neuropeptide Y (NPY), are constitutively expressed by the retinal pigment epithelial cells. Together these two neuropeptides induce anti-inflammatory cytokine production in endotoxin-stimulated macrophages and suppress phagocytosis of unopsonized bioparticles. These neuropeptides do not suppress the phagocytosis of opsonized bioparticles; however, they do suppress phagolysosome activation or formation. In this report, we studied the possibility that α-MSH with NPY suppress phagosome maturation within macrophages using opsonized OVA-coated magnetic beads to isolate and analyze the phagosomes. The magnetic bead–containing intercellular vesicles were isolated and assayed for Rab5, Rab7, LAMP1, Iad, and OVA. The macrophages cotreated with α-MSH and NPY were suppressed in Rab7 recruitment to the phagosome with suppression in LAMP1 expression but not in Iad expression. The results demonstrated that the α-MSH/NPY cotreatment suppressed phagosome maturation. In addition, the a-MSH/NPY–cotreated macrophages were suppressed in their ability to Ag stimulate CD4+ T cell proliferation. These results imply a potential mechanism of ocular immune privilege to divert Ag processing to prevent autoreactive effector T cells from binding their target cognate Ag within the ocular microenvironment.
True hermaphroditism exists when both ovarian and testicular tissues are present in the same person. This condition is quite rare and it is particularly rare for the subject to exhibit oogenesis and effective spermatogenesis.
A computational study of the wave phenomenon and probable cavitation that occurs when a droplet interacts with a shock is presented. A volume-of-fluid method with and without a cavitation model activated is employed. The model with no cavitation is used to clarify the droplet's internal wave field. The model is benchmarked using experimental data of a 22 mm water column impacted by a shock wave at Mach 2.4. Good agreement between the computational results for a two-dimensional (2D) circular droplet and the experimental results is demonstrated. A simplified 2D, square droplet is also considered in order to highlight the effects of interface curvature on the internal waves. Comparison of the results for the square and circular drops shows that the circular geometry diffuses the initial pressure wave while focusing the reflected wave. The three-dimensional (3D) spherical droplet was then analyzed. The internal wave behavior is similar to the 2D circular drop with enhanced diffusion and focusing. Two cavitation models were then used to explore the probability that cavitation occurs for a nominal sized raindrop interacting with shock waves, Mach 1.5–5. Two cavitation models, full Rayleigh–Plesset (FRP) and Schnerr-Sauer both predicted vapor formation at the same location with the FRP always predicting slightly higher amounts of vapor. The current setting for number of nuclei ensures that the simulation is not swamped by vapor formation but is unrealistically small. Therefore, while the work demonstrates that cavitation will occur, the full nature of the cavitation along with the impulsive pressure waves it should create is not currently captured.
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