Adipose-derived stem cells-conditioned medium improved osteogenic differentiation of induced pluripotent stem cells when grown on polycaprolactone nanofibers

Considering that the common osteogenic growth factors cannot be transplanted with stem cells to the patients, many studies are underway to find a replacement for these factors. Recently, it has been determined that mesenchymal stem cell (MSC)-derived conditioned medium (CM) contains effective factors in the bone formation process. In the current study, the synergistic effect of adipose-derived MSC’s CM, and polycaprolactone (PCL) scaffold was investigated on the osteogenic differentiation potential of human induced pluripotent stem cells (iPSCs). After scaffold fabrication by electrospinning and characterization by scanning electron microscopy, iPSCs proliferation in the presence of CM, PCL, and both was evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide. Then, iPSCs osteogenic differentiation was investigated while cultured on tissue culture plate and PCL under CM compared with the osteogenic medium using alizarin red staining, calcium content, alkaline phosphatase activity and gene and protein expression analysis. Proliferation rate of the iPSCs was increased while cultured under CM and its effect was synergistically enhanced by culture on PCL. Evaluation of the osteogenic markers was showed CM alone could induce osteogenic differentiation into the iPSCs and this potential was significantly increased while combined with PCL nanofibrous scaffold. According to the results, it was demonstrated that CM has an osteogenic induction property almost the same of the common osteogenic medium and it can also be used potentially with stem cells when transplant to the patients. CM can also help by prolonging cell survival at the site of the defect as well as accelerating healing process.     

Benefits of stimulus congruency for multisensory facilitation of visual learning

Background

Studies of perceptual learning have largely focused on unisensory stimuli. However, multisensory interactions are ubiquitous in perception, even at early processing stages, and thus can potentially play a role in learning. Here, we examine the effect of auditory-visual congruency on visual learning.

Methodology/Principle Findings

Subjects were trained over five days on a visual motion coherence detection task with either congruent audiovisual, or incongruent audiovisual stimuli. Comparing performance on visual-only trials, we find that training with congruent audiovisual stimuli produces significantly better learning than training with incongruent audiovisual stimuli or with only visual stimuli.

Conclusions/Significance

This advantage from stimulus congruency during training suggests that the benefits of multisensory training may result from audiovisual interactions at a perceptual rather than cognitive level.     

Mesosomal structures and antimicrobial activity induced by hemin oxidation or porphyrin photodynamic sensitization inStaphylococci

The porphyrin-dependent inactivation ofStaphyloccocus aureus and the induction of mesosomal structures are described. The antimicrobial activity of different photoactivated porphyrins was compared with the dark cytotoxic effect of hemin. Deuteroporphyrin, protoporphyrin, hematoporphyrin, and hematoporphyrin derivative (Hpd) markedly reduced cell growth upon irradiation with light. Photofrin II, the polymerized fraction of Hpd, and other synthetic porphyrins had no effect on staphylococcal growth. Hemin immediately inhibited cell viability in the dark and induced the development of an irregular cell wall, analyzed by scanning electron microscopy (SEM). Inside the cytoplasm a multivesicular mesosome was formed near the septum, as detected by transmission electron microscopy (TEM). The mesosomal volume and its frequency in the cells was increased in a time-dependent manner. The mesosome appearance was not related to fixation by glutaraldehyde or to post-fixation by osmium tetroxide. Glycosyl moieties stained by ruthenium red revealed the formation of membrane-like structures in the mesosome. It is concluded that oxygen-dependent reactions potentiated by porphyrins may induce disturbances in the synthesis of staphylococcal membrane and cell wall, revealed as mesosomes.