1. The technical problems remaining for human islet allografts are selection of the optimum method of preventing islet allograft rejection based on studies in the dog, adaptation of the mass islet isolation techniques to the human pancreas, and selection of a safe and optimum site for transplantation.

2. 4) Instead of taking out the vacuum glazing after the temperature in the vacuum chamber drops down and then sealing the pumpout tubes on it, as is operated in the traditional methods, the optimum method according to the invention, after sealing the edges of the glass sheets, pumps vacuum and seals the pumpout tubes by making use of, and in the period of, the afterheat of the vacuum glazing, so as to save both energy and operation time.