Non-chimerism and chimerism pseudo dicentric Y chromosome: two case reports about azoospermia and cytogenetic/molecular genetic analysis in the Chinese population.

OBJECTIVE: To report the cytogenetic and molecular genetic analysis of the first two cases of non-chimerism and chimerism karyotype in Chinese male patients who suffer from azoospermia, which may be caused by pseudo dicentric Y chromosomes. DESIGN: Case study. SETTING: Academic reproductive medicine center. PATIENTS: Two male patients with azoospermia, carrying pseudo dicentric Y chromosome. INTERVENTIONS: Review the records of inquiry, testicular biopsy, pathological examination, semen routine examination, endocrine evaluation, cytogenetic chromosomal analysis, and FISH detection of peripheral blood to evaluate Y chromosome deletion. MAIN OUTCOME MEASURES: To investigate the possible association among pseudo dicentric Y, chimeric status and azoospermia. RESULTS: Two patients were both diagnosed with azoospermia by a variety of andrology inspections. Further chromosomal analysis and FISH indicated their pseudo dicentric Y chromosome and different chimerism status. PCR confirmed simultaneous deletions of AZFb and AZFc regions in the Y chromosome of both patients. CONCLUSIONS: Pseudodicentric Y chromosome affecting the long arm may lead to a male phenotype by duplicating the sex-determining region of Y chromosome (SRY) fragment and chimeric status may further impact patient's hormone levels, which obstruct spermatogenesis. However, the deletion of the azoospermia factor (AZF) is likely the key factor that causes azoospermia.

Tissue factor and thrombomodulin expression on endothelial cell-seeded collagen modules for tissue engineering.

The creation of functional tissue engineering constructs to repair or replace diseased tissues requires a well-formed vasculature network within the construct and the endothelial cells lining that vascular bed must display a nonthrombogenic phenotype. A new approach to tissue engineering involves the assembly of smaller components (modules fabricated at the hundred micron scale) into larger constructs. The modules, collagen gel containing the particular tissue cell of interest, are covered with endothelial cells prior to assembly so that the interconnected channels that are formed are lined with endothelial cells, creating a mimic of a vascular network. Here, we confirmed (using confocal microscopy primarily) that the human umbilical vein endothelial cells, seeded on collagen gel modules without a second embedded cell and without flow, bore the molecular markers of low thrombogenicity. Two days, after seeding on the modules, endothelial cells displayed the typical cobblestone morphology, formed tight cell-cell junctions and covered the whole module surface. Immunofluorescence staining showed that at both 2 days and 7 days after seeding, only a few cells expressed tissue factor while this number was dramatically increased after TNFalpha stimulation. On the other hand, thrombomodulin was expressed by the majority of seeded cells and expression was reduced after TNFalpha stimulation.