Complement Permeability in Bio-Artificial Endocrine Pancreas Using a Diffusion Chamber

Immunoisolation is a potentially important approach to transplanting islets without any immunosuppressive therapy. This study was designed to investigate whether complement penetrates into the diffusion chamber that we developed for a bioartificial endocrine pancreas (Bio-AEP). The results showed that within 12–24 h, when a Nuclepore membrane (Nuclepore Corp., California) was the sole barrier, complement permeated 100%. However, the Nuclepore membrane used together with a mixed matrix prevented complement penetration. Also, the complement become inactivated during penetration through both the mixed matrix and the Nuclepore membrane with a pore size of 0.1 μm. In conclusion, immunoisolation of cells by a mixed matrix and a Nuclepore membrane of 0.1 μm pore size is a particularly effective method for transplanting xenogeneic cells. Thus, the clinical application of our Bio-AEP shows promise for long-term xenotransplantation without an immunosuppressant.

A PRECONCENTRATION TECHNIQUE FOR WATER ANALYSIS BY PIXE

The enrichment procedure of heavy metals ( Fe 3+, Co 2+, and Hg 2+) in water was examined in conjunction with in-air PIXE. The preconcentration step consisted of adsorption of dibenzyldithiocarbamate complexes of the metal ions onto dibenzylidene-D-sorbitol gels. The colloidal gels in solutions were then collected on a nuclepore membrane for direct irradiation by proton beams in a system of vertical beam type in-air PIXE. The amounts of the chemicals used in the enrichment were minimized to prepare thin target specimens with the homogeneous composition. The metal-recovery in the preconcentration step was confirmed to be quantitative in a wide range of the concentrations. The reproducibility and detection limit were shown and discussed for the present setup of PIXE analysis in our laboratory.

Astragalus Membranaceus Stimulates Human Sperm Motility In Vitro

Poor sperm motility is an important cause of male infertility. In an attempt to identify Chinese medicinal herbs that might improve human sperm motility in vitro, we screened water extracts of 18 herbs with a trans-membrane migration method which measured the percentage of sperm that moved across the 5 micron pores of a Nuclepore membrane from a semen-drug mixture into phosphate buffered saline during 2 hours incubation. Astragalus membranaceus was the only herb that showed a significant stimulatory effect. At 10 mg/ml, it increased the motility of sperm in semen to 146.6 ± 22.6 % of control. It also increased the motility of washed sperm to 138.2 ± 13.8% of control. Purification of the active component(s) from this herb as well as its application in assisted reproduction technology await further investigation.