Surface modification and DNA-binding assessment of nano-hydroxyapatite / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the impact of surface modification on the DNA-binding ability of nano-hydroxyapatite (nHA).</p><p><b>METHODS</b>Chemical co-precipitation-hydrothermal synthesis was utilized to prepare the nHA particles, and polyethylenimine (PEI) was used for surface modification of the nHA. Transmission electron microscopic (TEM) observation and zeta potential detection of the nHA were carried out before and after surface modification. The abilities of the nanoparticles, at different pH values and different concentrations, for DNA-binding and DNA protection against nuclease digestion were assessed before and after surface modification by electrophoresis.</p><p><b>RESULTS</b>TEM observation showed a short rod-like morphology of PEI-modified nHA with uniform particle size and good dispersion; the nHA without the modification tended to aggregate with poor dispersion. With a positive zeta potential, the PEI-modified nHA showed an obviously enhanced ability of DNA binding at different pH values and concentrations, with strong capacity to protect the DNA against Dnase I digestion. At the concentration of 250 µg/ml and a pH value of 7.0, the nHA-PEI showed an optimal efficiency of DNA-binding and DNA protection.</p><p><b>CONCLUSION</b>nHA with surface modification by PEI can serve as an effective vector for DNA binding and transfer.</p>

Predictive value of serum inhibin B levels as an indicator of the presence of testicular spermatozoa in nonobstructive azoospermia / 中华男科学杂志

<p><b>OBJECTIVE</b>To evaluate the predictive value of serum inhibin B (INH B) levels as an indicator of the presence of testicular spermatozoa in nonobstructive azoospermia.</p><p><b>METHODS</b>Forty patients with nonobstructive azoospermia (NOA), 20 patients with obstructive azoospermia (OA), and 10 fertile volunteers were involved in this study. A chemoluminescence method was used to measure the levels of FSH; Inhibin B was analysed by using sandwich enzyme-linked immuno-sorbent assay.</p><p><b>RESULTS</b>Patients with nonobstructive azoospermia has significantly higher levels of serum FSH [(21.34 +/- 12.15) IU/L] and significantly lower levels of inhibin B [(53.15 +/- 58.74) ng/L] than patients with obstructive azoospermia [FSH: (3.94 +/- 1.52) IU/L, INH B: (162.49 +/- 78.38) ng/L, P < 0.01] and fertile volunteers [FSH: (4.27 +/- 2.84) IU/L, INH B: (228.49 +/- 110.68) ng/L, P < 0.01]. Mean serum inhibin B were significantly higher in patients with nonobstructive azoospermia who had spermatozoa on TESE than in those in whom no spermatozoa was found on TESE [INHB: (90.31 +/- 72.18) ng/L vs (19.54 +/- 20.38) ng/L, r = 0.528, P < 0.01], but mean FSH levels did not have similar predictive power (P > 0.05).</p><p><b>CONCLUSION</b>Serum INH B level seems to be more accurate than serum FSH in the prediction of presence of testicular spermatozoa in patients with nonobstructive azoospermia. Serum inhibin B determination may be substitute of TESE as a diagnostic index.</p>