Testicular germ cell transplantation into the seminiferous tubules is at present the only way to induce spermatogenesis from a given source of spermatogonial stem cells. Here we show an alternative method that harnesses the self-organizing ability of testicular somatic cells. The testicular cells of embryonic or neonatal mice or rats and of newborn pigs were dissociated into single cells. Each of them reorganized into a tubular structure following implantation into the subcutis of immunodeficient mice. When mouse germline stem (GS) cells derived from spermatogonial stem cells and expanded in culture were intermingled with testicular cells of rodents, they were integrated in the reconstituted tubules and differentiated beyond meiosis into spermatids. Normal offspring were produced by the microinjection of those spermatids into oocytes. This method could be applicable to various mammalian species and useful for producing functional gametes from GS cells in a xenoectopic environment.

Objectives: To describe and to validate a novel patient-specific virtual-reality based simulator for laparoscopic surgery. Methods: Three surgeons carried out 13 preoperative simulations at Yokohama City University Hospital, Yokohama, Kanagawa, Japan, from 2011 to 2012. The procedures included seven nephrectomies, four partial nephrectomies and two pyeloplasties. We evaluated whether the anatomies reproduced by the simulator matched those encountered during the actual operations. Furthermore, the surgeons were asked to use visual analog scales (from 1 to 5; higher scores are better) to evaluate the anatomical integrity and utility of the simulations, and their intraoperative confidence during the subsequent surgical procedures. Results: The simulator reproduced the patients' anatomies almost perfectly. Only a few minor mistakes were identified. Regarding the surgeons' evaluations of the system, the mean scores for the anatomical integrity and utility of the simulations, and the surgeons' intraoperative confidence were 3.4, 4.2 and 4.1, respectively. In all 13 cases, the surgeons were able to carry out preoperative training with ease, and they stated that the simulator was useful for producing preoperative images. Conclusions: A patient-specific simulator for laparoscopic renal surgery has been successfully developed. This system correctly reproduces anatomical structures, and it seems to be a useful preoperative training tool.