Latch assembly of a keeper structure and a latch structure has a frame a frame recess, a guide pin received in said frame recess for oscillating rotation, the guide pin having a handle tab for rotating the guide pin and a dog projecting from said guide pin. 1, afford in vivo islet protection following a 2-day course of intense treatment in autoimmune diabetes-prone, non-obese diabetic mice, a widely used model of Type 1 diabetes, which resulted in a diabetes-free state for one year without apparent toxicity and the need to use insulin. Entrained air and impurities may be displaced from the passages by the flow of molten metal and vented or entrapped by a biscuit.