Efficient simulation of intensity profile of light through subpixel-matched lenticular lens array for two- and four-view auto-stereoscopic liquid-crystal display.

Both an analytical formula and an efficient numerical method for simulation of the accumulated intensity profile of light that is refracted through a lenticular lens array placed on top of a liquid-crystal display (LCD) are presented. The influence due to light refracted through adjacent lens is examined in the two-view and four-view systems. Our simulation results are in good agreement with those obtained by a piece of commercial software, ASAP, but our method is much more efficient. This proposed method allows one to adjust the design parameters and carry out simulation for the performance of a subpixel-matched auto-stereoscopic LCD more efficiently and easily.

Mouse salivary glands and human beta-defensin-2 as a study model for antimicrobial gene therapy: technical considerations.

Transduction of salivary glands with antimicrobial peptide genes has great potential for oral infection control. Our ultimate goal is to introduce antimicrobial peptide genes into salivary glands that secrete these peptides into saliva to control bacterial/fungal infection in the oral cavity. However, an animal study model to test this potential has not been established. Therefore, we determined to test (i) whether the potent antimicrobial peptide human beta-defensin-2 (hBD-2) can be overexpressed in saliva after transduction of salivary glands and (ii) whether oral fungal infection can be developed in a NOD/SCID murine model. Lentiviral vector SIN18cPPTRhMLV bearing hBD-2 cDNA was introduced into SCID mouse submandibular glands via cannulation. Reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry or enzyme-linked immunosorbent assay (ELISA) were performed to detect hBD-2 expression in glands or in saliva. Candida albicans 613p was inoculated orally into SCID mice to establish oral candidiasis. Whilst expression of hBD-2 was detected in mouse salivary glands by RT-PCR and immunohistochemistry 1 day or 1 week following delivery of lentivirus, hBD-2 was not detected in saliva. There was recoverable C. albicans from the oral cavity and gastrointestinal tract 4 days to 4 weeks after infection, but there was no establishment of observable oral candidiasis in SCID mice under a stereomicroscope. Our data indicate that lentiviral vectors transduce mouse salivary glands, but not at a sufficient level to allow hBD-2 detection in saliva. Other vectors for gene transduction and additional treatment of SCID mice to establish oral candidiasis are needed in order to utilise mouse salivary glands to test antimicrobial gene therapy.

[Construction of eukaryotic expression clone for human amelogenin].

OBJECTIVE: To construct-the eukaryotic expression clone for human amelogenin. METHODS: Total RNA was isolated from human fetal tooth buds. RT-PCR was used to amplify the amelogenin encoding region, and the amplified fragment for human amelogenin was inserted into eukaryotic expression vector PcDNA 3.1. The positive clones were selected and analyzed by restriction endonuclease mapping and DNA sequencing. RESULTS: 570 bp fragment was produced by RT-PCR; it was of the same size as expected based on human ameloginin mRNA encoding area length. The sequence of the inserted fragment from the recombinant clone PcDNA 3.1-AMG was consistent with that of AMELX from GenBank with one mismatch on 485 from G to C, without affecting the amino acid sequence. CONCLUSION: The eukaryotic expression clone PcDNA 3.1-AMG was successfully constructed with the properly inserted DNA sequence encoding mature human amelogenin.

Analysis of the interchannel response in a MEMS 1 x N(2) wavelength-selective switch.

A theoretical model based on Fourier optics and the power-coupling overlap integral is built to investigate the interchannel response in a micro-electro-mechanical systems 1xN(2) wavelength-selective switch. The simulation results demonstrate that the interchannel response depends significantly on the output port location and the radius of curvature of the micromirrors. For the output originally aligned with the input along the dispersion direction, it is possible to achieve interchannel-response suppression by rotating the two-dimensional (2D) collimator array by a slight angle, e.g., 20 degrees. Experimental results under different conditions are also shown.

Capacity of human beta-defensin expression in gene-transduced and cytokine-induced cells.

The purpose of this study was to determine the capacity of cells transduced with human beta-defensins (HBDs) to express antimicrobial peptides, since sufficient expression level is required for effective antimicrobial activity. Retroviral vector pBabeNeo and lentiviral vector SIN18cPPTRhMLV (SIN18) carrying HBDs were utilized to transduce non-HBD-expressing cells such as fibroblasts or HBD-producing oral epithelial cells. We found that HBD-3 gene transfer to fibroblasts was possible not via retrovirus but by direct vector transfection. SIN18 had high transduction efficiencies (80.9-99.9%) and transduced cells expressed higher amounts of HBD-2 than those by pBabeNeo. Primary human gingival epithelial cells (HGECs) expressed greater amounts of HBD-2 than primary fibroblasts after lentiviral transduction. Additionally, HBD-2 secretion from transduced HGECs cells was further increased when stimulated with IL-1 or TNFalpha. Our data indicate that while HBD-2 expression is limited in primary fibroblasts, its expression in HGECs may be maximized by gene transduction plus cytokine induction.

Human ß-defensin-2 gene transduction of dental pulp cells: A model for pulp antimicrobial gene therapy.

The objective of this study was to determine whether cells from human pulp can be transduced to express the antimicrobial peptide--human ß-defensin-2 (HBD-2). Primary human pulp cells and gingival fibroblasts from normal tissue, as well as two mouse cell lines (NIH 3T3 and AT-84) and a human cell line SCC-9 were transduced with a retroviral vector carrying HBD-2 cDNA. ELISA and Northern blot analyses were performed to detect HBD-2 expression by these transduced cells. Antimicrobail assays using recombinant HBD-2 were performed on two caries-associated bacteria Streptococcus mutnas and Lactobacillus acidophilus. The results showed that transduced pulp cells secreted 62.4 ± 27.2 ng/3 days of HBD-2, which was comparable to that by NIH 3T3 (78.0 ± 14.1 ng/4 days), and higher than those by gingival fibroblasts (17.9 ± 7.9 ng/3 days), AT-84 (2.6 ± 1.0 ng/3 days), and SCC-9 (47.6 ± 9.9 ng/3 days). Northern blot analysis showed that the levels of HBD-2 mRNA expression correlated with their protein secretion levels. There was approximately 50% reduction of growth when S. mutans and L. acidophilus were exposed to HBD-2 at 1 µM. Pulp cells appear to be suitable for HBD-2 transduction using retroviral vectors, suggesting a potential for use in controlling pulpal infections.