Methacrylated gelatin and platelet-rich plasma based hydrogels promote regeneration of critical-sized bone defects.

Physiological repair of large-sized bone defects requires instructive scaffolds with appropriate mechanical properties, biocompatibility, biodegradability, vasculogenic ability and osteo-inductivity. The objective of this study was to fabricate in situ injectable hydrogels using platelet-rich plasma (PRP)-loaded gelatin methacrylate (GM) and employ them for the regeneration of large-sized bone defects. We performed various biological assays as well as assessed the mechanical properties of GM@PRP hydrogels alongside evaluating the release kinetics of growth factors (GFs) from hydrogels. The GM@PRP hydrogels manifested sufficient mechanical properties to support the filling of the tissue defects. For biofunction assay, the GM@PRP hydrogels significantly improved cell migration and angiogenesis. Especially, transcriptome RNA sequencing of human umbilical vein endothelial cells and bone marrow-derived stem cells were performed to delineate vascularization and biomineralization abilities of GM@PRP hydrogels. The GM@PRP hydrogels were subcutaneously implanted in rats for up to 4 weeks for preliminary biocompatibility followed by their transplantation into a tibial defect model for up to 8 weeks in rats. Tibial defects treated with GM@PRP hydrogels manifested significant bone regeneration as well as angiogenesis, biomineralization, and collagen deposition. Based on the biocompatibility and biological function of GM@PRP hydrogels, a new strategy is provided for the regenerative repair of large-size bone defects.

A combination of the K-L and S-P approaches for treating acetabular posterior wall factures accompanied by femoral head fractures with open reduction and internal fixation.

BACKGROUND: In clinical practice, acetabular posterior wall fracture combined with femoral head fracture is rare. However, with the increasing number of engineering and traffic accidents, such fractures, have increased significantly in recent years. This paper aims to explore the clinical efficiency of the Kocher-Langenbeck (K-L) and Smith-Petersen (S-P) combined approaches for open reduction and internal fixation (ORIF) of acetabular posterior wall fractures accompanied by femoral head fractures (Pipkin type IV fractures). METHODS: A retrospective study was conducted on 8 patients who underwent open reduction and internal fixation (ORIF) of Pipkin type IV fractures through the K-L combined with S-P approach in our hospital from January 2015 to January 2020. All 8 patients were successfully operated on without serious complications, such as important blood vessel and nerve damage, with an operation time of 143.8 ± 44.38 min and intraoperative blood loss of 225 ± 70.71 ml. Perioperative data were recorded. The Harris score was used to evaluate the clinical effect. Fracture reduction quality was evaluated according to the Matta radiological standard. The grade of ectopic ossification was evaluated by the Brooker grading method, and the stage of femoral head necrosis was evaluated by Ficat-Arlet staging. RESULTS: The Harris score increased significantly from 57.38 ± 4.779 at 3 months, to 76.13 ± 3.682 at 6 months, 88.25 ± 3.495 at 12 months, and 92.13 ± 2.232 at 36 months postoperatively. After statistical analysis, compared with the previous observation time point, the data comparison differences between the groups were statistically significant. P < 0.001, P < 0.001, P < 0.05). By the time of the latest follow-up, 6 of the 8 patients had recovered to the level of pre-injury sports capacity. In contrast, the other 2 patients remained below the level of pre-injury sports capacity. In terms of imaging evaluation, the quality of fracture reduction on radiographs was graded as excellent in 6 patients and good in 2 patients according to Matta's criteria. At the last follow-up, no heterotopic ossification or femoral head necrosis was found in of all the images. In addition, the hip joint space was normal in 6 cases, mildly narrowed in 1 case, and clearly narrowed in 1 case. CONCLUSIONS: The K-L combined with S-P approach provides effective exposure for the reduction and fixation of Pipkin type IV fractures and achieves satisfactory clinical outcomes.

Fine mapping of qPH9, a major quantitative trait locus, responsible for plant height in foxtail millet [Setaria italica (L.) P. Beauv.].

Plant height is vital for crop yield by influencing plant architecture and resistance to lodging. Although lots of quantitative trait loci (QTLs) controlling plant height had been mapped in foxtail millet, their contributions to phenotypic variation were generally small and mapping regions were relatively large, indicating the difficult application in molecular breeding using marker-assisted selection (MAS). In the present paper, a total of 23 QTLs involving in 15 traits were identified via a high-density Bin map containing 3024 Bin markers with an average distance of 0.48 cM through an F2 population. Among them, qPH9, with a large phenotypic variation explained (51.6%) related to plant height, was one of the major QTLs. Furthermore, qPH9 was repeatedly detected in multi-environments under field conditions using two new developed F2 populations from the same F1 plant, and was narrowed down to a smaller interval of 281 kb using 1024 recessive F2 individuals from the same F1 plant. Finally, we found that there was an extremely significant correlation between marker MRI1016 and plant height, and further speculated that Seita.9G088900 and Seita.9G089700 could be key candidates of qPH9. This study laid an important foundation for the cloning of qPH9 and molecular breeding of dwarf varieties via MAS. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01261-w.