A nanofibrous PHBV tube with Schwann cell as artificial nerve graft contributing to Rat sciatic nerve regeneration across a 30-mm defect bridge

Abstract

A nanofibrous PHBV nerve conduit has been used to evaluate its efficiency based on the promotion of nerve regeneration in rats. The designed conduits were investigated by physical, mechanical and microscopic analyses. The conduits were implanted into a 30-mm gap in the sciatic nerves of the rats. Four months after surgery, the regenerated nerves were evaluated by macroscopic assessments and histology. This polymeric conduit had sufficiently high mechanical properties to serve as a nerve guide. The results demonstrated that in the nanofibrous graft with cells, the sciatic nerve trunk had been reconstructed with restoration of nerve continuity and formatted nerve fibers with myelination. For the grafts especially the nanofibrous conduits with cells, muscle cells of gastrocnemius on the operated side were uniform in their size and structures. This study proves the feasibility of artificial conduit with Schwann cells for nerve regeneration by bridging a longer defect in a rat model.     

microRNA-501-5p promotes cell proliferation and migration in gastric cancer by downregulating LPAR1

In spite of the achievement in treatment, the gastric cancer (GC) mortality still remains high. MicroRNAs (miRNAs) are a group of small noncoding RNAs that play a crucial part in tumor progression. In this study, we explored the expression and function of microRNA-501-5p (miR-501-5p) in GC cell lines. Quantitative real-time polymerase chain reaction assay results suggested that miR-501-5p was significantly upregulated in GC tissues and cell lines. And, the Cell Counting Kit-8 colony formation and cell migration assay results showed that the downregulation of miR-501-5p decreased GC cell proliferation and migration. Besides that, we found that GC cell cycle was arrested in G2 phase and cell apoptosis rate was increased by silencing the expression of miR-501-5p in GC cell lines using the flow cytometry. We also found that miR-501-5p could directly target lysophosphatidic acid receptor 1 (LPAR1) and negatively regulate LPAR1 expression in GC cell lines by performing dual-luciferase reporter gene assay and Western blot analysis. And, LPAR1 was significantly downregulated in GC tissues and inversely correlated with miR-501-5p expression. Furthermore, LPAR1 downregulation promoted cell proliferation and migration, which were attenuated by cotransfection of miR-501-5p inhibitor in GC cells. In conclusion, miR-501-5p can promote GC cell proliferation and migration by targeting and downregulating LPAR1. miR-501-5p/LPAR1 may become a potential therapeutic target for GC treatment.     

Prenatal diagnosis and molecular cytogenetic characterization of a de novo proximal interstitial deletion of chromosome 4p (4p15.2→p14)

We present prenatal diagnosis of de novo proximal interstitial deletion of chromosome 4p (4p15.2→p14) and molecular cytogenetic characterization of the deletion using uncultured amniocytes. We review the phenotypic abnormalities of previously reported patients with similar proximal interstitial 4p deletions, and we discuss the functions of the genes of RBPJ, CCKAR, STIM2, PCDH7 and ARAP2 that are deleted within this region.     

The telocentric tandem repeat at the p-arm is not conserved in Mus musculus subspecies

Mouse chromosomes, with the exception of the Y chromosome, are telocentric. The telomere at the p-arm is separated from the centromere by the tL1 sequence and TLC tandem repeats. A previous report showed that the TLC array was also conserved in other strains of the subgenus Mus. These results suggest that the TLC arrays promote the stable evolutionary maintenance of a telocentric karyotype in the subgenus Mus. In this study, we investigated the degree of conservation of TLC arrays among a variety of wild-derived inbred strains, all of which are descendants of wild mice captured in several areas of the world. Genomic PCR analysis indicates that the sequential order of telomere-tL1 is highly conserved in all strains, whereas tL1-TLC is not. Next, Southern blot analysis of DNAs isolated from a panel of mouse subspecies showed both Mus musculus domesticus and Mus musculus castaneus subspecies possess TLC arrays. Unexpectedly, this repeat appears to be lost in almost all Mus musculus musculus and Mus musculus molossinus subspecies, which show a clear geographic divide. These results indicate that either other unknown sequences were replaced by the TLC repeat or almost all M. m. musculus and M. m. molossinus subspecies do not have any sequence between the telomere and minor satellites. Our observation suggests that the TLC array might be evolutionarily unstable and not essential for murine chromosomal conformation. This is the first example of the subspecies-specific large genome alterations in mice.     

Conditioning of surfaces by macromolecules and its implication for the settlement of zoospores of the green alga Ulva linza

Conditioning, ie the adsorption of proteins and other macromolecules, is the first process that occurs in the natural environment once a surface is immersed in seawater, but no information is available either regarding the conditioning of surfaces by artificial seawater or whether conditioning affects data obtained from laboratory assays. A range of self-assembled monolayers (SAMs) with different chemical terminations was used to investigate the time-dependent formation of conditioning layers in commercial and self-prepared artificial seawaters. Subsequently, these results were compared with conditioning by solutions in which zoospores of the green alga Ulva linza had been swimming. Spectral ellipsometry and contact angle measurements as well as infrared reflection absorption spectroscopy (IRRAS) were used to reveal the thickness and chemical composition of the conditioning layers. The extent that surface preconditioning affected the settlement of zoospores of U. linza was also investigated. The results showed that in standard spore settlement bioassays (45–60 min), the influence of a molecular conditioning layer is likely to be small, although more substantial effects are possible at longer settlement times.