Theoretical analysis of mechanisms that generate the pigmentation pattern of animals

Mechanisms of animal skin pigment pattern formation have long been of interest to developmental and mathematical biologists. Although there has been a well-studied theoretical hypothesis-the reaction-diffusion system-that is able to reproduce the variety of skin patterns, a lack of molecular evidence has kept it just a hypothesis. In this review, we summarize the results of theoretical studies to date for researchers not familiar with their mathematical underpinnings, and we discuss future approaches that will more fully integrate mathematical models and experimental analyses.     

The ability of natural tolerance to be applied to allogeneic tissue: determinants and limits

Background  

Transplant rejection has been considered to occur primarily because donor antigens are not present during the development of the recipient's immune system to induce tolerance. Thus, transplantation prior to recipient immune system development (pre-immunocompetence transplants) should induce natural tolerance to the donor. Surprisingly, tolerance was often not the outcome in such 'natural tolerance models'. We explored the ability of natural tolerance to prevent immune responses to alloantigens, and the reasons for the disparate outcomes of pre-immunocompetence transplants.     

Spontaneous teratoma in a Sprague-Dawley rat

An 6-week-old male Sprague-Dawley rat which had undergone no experimental treatment died from enlargement of the abdomen. At necropsy, a spherical mass measuring about 3 X 4cm in diameter was connected to the retroperitoneal region cross to the middorsal line of the body. The tumor was composed of skin, ganglion, striated and smooth muscle, cartilage, bone, pancreas, glands, lymph node, and fibrous and adipose tissue, and diagnosed as teratoma.