Modifying Antibody DNA for Site-Specific Binding

Humanized antibody plasmid DNA was modified to allow the distance between the Fc fragment and antigen binding sites of immunoglobulin G (IgG) antibodies to be studied. Specific variable heavy (VH) and variable light (VL) genes were inserted into heavy and light chain plasmids so that dye molecules can be easily attached to the expressed protein, and further inspection of antibody structure and function can be conducted via single molecule Förster resonance energy transfer (FRET). First, VH and VL genes were inserted into humanized antibody plasmids through the technique of ligation. The ligation product was then transformed into Escherichia coli cells, allowing the success of the ligation reaction to be determined by methods of agarose gel electrophoresis and sequencing of the plasmid DNA

Effect of Base Curve Radius of Therapeutic Lenses on Epithelial Healing after Laser-Assisted Subepithelial Keratectomy

PURPOSE: To determine the effect of the base curve radius (BCR) of therapeutic soft contact lens (T-lens) on epithelial healing after laser-assisted subepithelial keratectomy (LASEK). METHODS: Ninety-two eyes in 47 patients with myopia were prospectively evaluated after LASEK. All the patients wore T-lenses with the BCR (R1) randomly chosen after LASEK. The T-lenses were removed after complete healing of the epithelial wounds. We calculated an estimated BCR (R2) from postoperative topography using a diopter conversion table. The patients were divided into two groups according to the differences between the BCR (R1) and the estimated BCR (R2). The flat fitting group was R1 > R2 (Group A), and the steep fitting group was R1R2) had 53 eyes, and Group B (R1<R2) had 39 eyes. Group A showed a shorter epithelial healing time than Group B (5.8+/-1.7 days vs. 6.7+/-2.1 days, p=0.04). CONCLUSIONS: The flat fitting group showed a shorter epithelial healing time than the steep fitting group after LASEK

Structural design of contact lens-based drug delivery systems; in vitro and in vivo studies of ocular triggering mechanisms

This study identifies and investigates the potential use of in-eye trigger mechanisms to supplement the widely available information on release of ophthalmic drugs from contact lenses under passive release conditions. Ophthalmic dyes and surrogates have been successfully employed to investigate how these factors can be drawn together to make a successful system. The storage of a drug-containing lens in a pH lower than that of the ocular environment can be used to establish an equilibrium that favours retention of the drug in the lens prior to ocular insertion. Although release under passive conditions does not result in complete dye elution, the use of mechanical agitation techniques which mimic the eyelid blink action in conjunction with ocular tear chemistry promotes further release. In this way differentiation between passive and triggered in vitro release characteristics can be established. Investigation of the role of individual tear proteins revealed significant differences in their ability to alter the equilibrium between matrix-held and eluate-held dye or drug. These individual experiments were then investigated in vivo using ophthalmic dyes. Complete elution was found to be achievable in-eye; this demonstrated the importance of that fraction of the drug retained under passive conditions and the triggering effect of in-eye conditions on the release process. Understanding both the structure-property relationship between drug and material and in-eye trigger mechanisms, using ophthalmic dyes as a surrogate, provides the basis of knowledge necessary to design ocular drug delivery vehicles for in-eye release in a controllable manner