Time-resolved MR angiography with SENSE is effective for the diagnosis of pulmonary embolism.

Marine collagen derived from fish scales, skin, and bone has been widely investigated for application as a scaffold and carrier due to its bioactive properties, including excellent biocompatibility, low antigenicity, and high biodegradability and cell growth potential. Fish type I collagen is an effective material as a biodegradable scaffold or spacer replicating the natural extracellular matrix, which serves to spatially organize cells, providing them with environmental signals and directing site-specific cellular regulation. This study was conducted to confirm the safety of fish (tilapia) atelocollagen for use in clinical application. We performed in vitro and in vivo biological studies of medical materials to investigate the safety of fish collagen. The extract of fish collagen gel was examined to clarify its sterility. All present sterility tests concerning bacteria and viruses (including endotoxin) yielded negative results, and all evaluations of cell toxicity, sensitization, chromosomal aberrations, intracutaneous reactions, acute systemic toxicity, pyrogenic reactions, and hemolysis were negative according to the criteria of the ISO and the Ministry of Health, Labour and Welfare of Japan. The present study demonstrated that atelocollagen prepared from tilapia is a promising biomaterial for use as a scaffold in regenerative medicine.

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Retroviral transduction of four transcription factors (Oct4, Sox2, Klf4 and c-Myc) or three factors, excluding c-Myc, has been shown to initiate a reprogramming process that results in the transformation of murine fibroblasts to induced pluripotent stem (iPS) cells, and there has been a rapid increase in the number of iPS cell-based preclinical trials. In this study, the effects of these transcription factors were evaluated regarding the growth and differentiation of murine iPS cells under hypoxia. Based on the results of RT-PCR and alizarin red S staining, there were no statistical differences in the growth and differentiation of iPS cells or the induction of iPS cells to osteoblasts under hypoxia between the transcription factor groups. Furthermore, the function of hypoxia inducible factors (HIFs) in murine iPS cells under hypoxia was investigated in relation to the morphology and expression of transcription factors using RT-PCR and Western blotting. The HIF-2α knockdown group exhibited a decrease in the colony size of the iPS cells. The HIF-2α or -3α knockdown group demonstrated a statistically significant decrease in the transcription factor expression compared to that observed in the control group. These results demonstrate that HIF-2α among HIFs is the most influential candidate for the maintenance of the pluripotency of murine iPS cells.