Hair follicle melanocyte cells as a renewable source of melanocytes for culture and transplantation

Objective: Advances in melanocyte culture techniques have not yet led to reliable clinical methods for treating hypopigmentation disorders. We hypothesized that melanocytes harvested from plucked hair follicles may provide a renewable source of melanocytes for the treatment of hypopigmentation. Methods: Hairs with attached cells from the follicles were plucked from Yucatan pigs and implanted in a collagen-glycosaminoglycan matrix for either immediate or delayed implantation into full-thickness excisional porcine wounds. Wounds were allowed to heal and were biopsied at 2 and 4 weeks, respectively. Results: Fully healed wounds with transplanted hair follicles showed central areas of dark pigmentation corresponding to the location of implanted hair follicles. Corresponding collagen-glycosaminoglycan matrix wounds showed no central areas of pigmentation. Conclusions: Hair follicle--derived melanocytes may potentially serve as a renewable source of pigment-producing cells for treating hypopigmentation disorders

Reinsurance and the firm value: Theory and evidence

This study examines the economics of reinsurance in the property-liability insurance industry. In particular, it examines the role of taxes in motivating the reinsurance transactions between firms. Just as leasing is used as a form of arbitrage between taxpayers on different tax schedules or facing differing marginal tax rates, reinsurance may be used as a form of tax arbitrage across insurers. In a world of certainty, this study shows that there is no gain from reinsurance trade as long as insurers choose an optimal mix of investments in taxable and tax-exempt assets; this result provides a Modigliani-Miller type irrelevancy theorem with equilibria. In a world of uncertainty, differences in the convexity of the tax claim on the firm drive the reinsurance tax arbitrage. However, other stakeholders may also have non-linear claims on the firm\u27s value, and consequently the value of their claims will be affected by reinsurance. Therefore, this study examines the effect of reinsurance on firm value. This is first shown with an expected value model of stakeholder claims, which is sufficient to reveal the tax arbitrage process. These results are confirmed and extended using a more acceptable pricing model, specifically an option pricing model. These models stated produce a set of testable hypotheses, which are then tested empirically. The test results support the tax arbitrage argument for reinsurance trade