Complete Human and Rat Ex Vivo Spermatogenesis from Fresh or Frozen Testicular Tissue.

Until now, complete ex vivo spermatogenesis has been reported only in the mouse. In this species, the duration of spermatogenesis is 35 days, whereas it is 54 days in the rat and 74 days in humans. We performed long-term (until 60 days) cultures of fresh or frozen rat or human seminiferous tubule segments in a bioreactor made of a hollow cylinder of chitosan hydrogel.

[Semen cryopreservation in adolescent with cancer: at which age can it be proposed?].

The increased incidence of tumors in children and adolescents (Lacour, 2010), as well as therapeutic advances in recent decades, have led to an increase of fertility disorders in young adult cancer survivors. In pubescent boys, the use of cryopreserved sperm and assisted reproductive technology (ART) is a validated preventive option. Currently, there is no consensus on the age at which the semen cryoconservation has to be proposed.

Ceramide and its transport protein (CERT) contribute to deterioration of mitochondrial structure and function in aging oocytes.

In women as well as in mice, oocytes exhibit decreased developmental potential (oocyte quality) with advanced age. Our current data implicate alterations in the levels of oocyte ceramide and associated changes in mitochondrial function and structure as being prominent elements contributing to reduced oocyte quality. Both ROS levels and ATP content were significantly reduced in aged oocytes.

Genetic variance modifies apoptosis susceptibility in mature oocytes via alterations in DNA repair capacity and mitochondrial ultrastructure.

Although the identification of specific genes that regulate apoptosis has been a topic of intense study, little is known of the role that background genetic variance plays in modulating cell death. Using germ cells from inbred mouse strains, we found that apoptosis in mature (metaphase II) oocytes is affected by genetic background through at least two different mechanisms. The first, manifested in AKR/J mice, results in genomic instability.

Molecular requirements for doxorubicin-mediated death in murine oocytes.

We previously published evidence that oocytes exposed to doxorubicin (DXR), a widely used chemotherapeutic agent, rapidly undergo morphological and biochemical changes via discrete effector signaling pathways consistent with the occurrence of apoptosis. In this report, we elucidated the molecular requirements for actions of this drug in oocytes. Our results indicate that within 1 h of exposure DXR causes rapid DNA damage, and commits the oocyte to cytoplasmic fragmentation by the fourth hour, followed by delayed oocyte activation and execution of cytoplasmic fragmentation.

Epigenetic marks at BRCA1 and p53 coding sequences in early human embryogenesis.

In the vertebrate genome, methylation of deoxycytosine residues of CpGs dinucleotide has been associated with transcriptional silencing of genes, parental imprinting, X-inactivation and chromatin remodelling. In human somatic tissues, the 5' end of the BRCA1 CpG island is methylated, whereas this region is unmethylated in mature germ cells and early embryos. In gametes, as in somatic tissues, the CpG sites in the coding region are methylated.

Comparison of two blastocyst culture systems: coculture on Vero cells and sequential media.

Objective: To compare two blastocyst culture systems: culture on Vero cells and sequential media in the same time period.

Design: Retrospective study.

Setting: Institutional practice assisted reproductive technology center.