Efficient cryopreservation of testicular tissue: effect of age, sample state, and concentration of cryoprotectant.

Objective: To study the effect of age and sample state on cryopreservation of testicular tissue, evaluate toxicity of commonly used cryoprotectants (CPs), and determine their optimal concentration for use.

Design: Prospective experimental study.

Setting: Academic research unit.

Very small embryonic-like stem cells with maximum regenerative potential get discarded during cord blood banking and bone marrow processing for autologous stem cell therapy.

Very small embryonic-like stem cells (VSELs) are possibly lost during cord blood banking and bone marrow (BM) processing for autologus stem cell therapy mainly because of their small size. The present study was conducted on human umbilical cord blood (UCB, n=6) and discarded red blood cells (RBC) fraction obtained after separation of mononuclear cells from human BM (n=6), to test this hypothesis. The results show that VSELs, which are pluripotent stem cells with maximum regenerative potential, settle along with the RBCs during Ficoll-Hypaque density separation.

Newer insights into premeiotic development of germ cells in adult human testis using Oct-4 as a stem cell marker.

The transcription factor octamer-binding transforming factor 4 (Oct-4) is central to the gene regulatory network responsible for self-renewal, pluripotency, and lineage commitment in embryonic stem (ES) cells and induced pluripotent stem cells (PSCs). This study was undertaken to evaluate differential localization and expression of two major transcripts of Oct-4, viz. Oct-4A and Oct-4B, in adult human testis.