Shooting habits of youth recreational firearm users.

Objective: This study surveyed youth recreational firearm users (YRFUs) regarding shooting habits, reported use of hearing protection devices (HPDs), self-assessed auditory status, and attitudes about firearm noise and hearing loss.

Design: A descriptive study using a 28-item survey administered by personal interview.

Study Sample: Two-hundred and ten youth aged 10 to 17 years responded.

Developing a clinical-grade cryopreservation protocol for human testicular tissue and cells.

Recent work in preservation of female fertility as well as new information on the nature of spermatogonial stem cells has prompted an investigation into the possibility of an effective clinical-grade procedure for the cryopreservation of testicular cells and/or tissue. Clinical-grade reagents, validated equipment, and protocols consistent with cGTP/cGMP standards were used in developing a procedure suitable for the safe and effective cryopreservation of human testicular cells and tissues. These procedures were designed to be compliant with the relevant FDA regulations.

Identification and characterization of repopulating spermatogonial stem cells from the adult human testis.

Background: This study was conducted to identify and characterize repopulating spermatogonial stem cells (SSCs) in the adult human testes.

Methods: Testes biopsies from obstructive azoospermic patients and normal segments of human testicular tissue were used. Flow cytometry, real-time PCR and immunohistochemical analysis were performed.

Differentiation potential of germ line stem cells derived from the postnatal mouse ovary.

General belief in reproductive biology is that in most mammals female germ line stem cells are differentiated to primary oocytes during fetal development and oogenesis starts from a pool of primordial follicles after birth. This idea has been challenged previously by using follicle kinetics studies and demonstration of mitotically active germ cells in the postnatal mouse ovary (Johnson et al., 2004; Kerr et al.

Establishment of cell lines from mouse embryos with early embryonic lethality.

It is often difficult to determine molecular mechanisms leading to early embryonic lethality of genetically modified mice due to lack of cells for further analyses. The authors describe here establishment of mouse embryonic fibroblast (MEF) cell lines from gastrulation stage embryos. In this example, using a combination of in vivo and in vitro techniques, the authors successfully generated MEF cell lines that lack both fibronectin (FN) and focal adhesion kinase (FAK).