The approach of stem cell transplantation to treat different types of diseases has been becoming a hot issue in the field of regenerative medicine.Potentially, bone marrow mesenchymal stem cells (BMMSCs) possess strong proliferation and multi-di-rection differentiation ability .Under special certain kind of induction circumstances , BMMSCs can trans-differentiate into myocardial cells, osteoblasts, fat cells, neurons, endothelial cells.It is difficult that how to obtain enough BMMSCs for basic and clinical studies using BMMSCs treating diseases .Currently , there are many methods of in vitro proliferation of BMMSCs with advantages and disadvan -tages.In this paper, an overview of BMMSCs proliferation strategy in vitro is provided .

[Abstract ] Objective Liver cirrhosis modeling with carbon tetrachloride (CCL4) may be influenced by many factors, such as drug concentration and dosing methods.In this article, we explored the influences of different concentrations and different dosing methods and time of CCL4 on the induction of liver cirrhosis in rats. Methods We constructed rat models of liver cirrhosis with different con-centrations of CCL4(30%and 50%), using different dosing methods (subcutaneous injection, intraperitoneal injection, and intragastric administration) , and for different lengths of dosing time (8 wk, 10 wk, and 12 wk) .We collected blood and liver tissues from the rats at different time points for HE and MTC staining, biochemical and histomorphological scores based on the Scoring Model for Liver Cirrho-sis Disease (SLCD, expressed by R) and the Laennec Fibrosis Scoring System (LFSS, expressed by L), and analysis of the results by 3 ×2 ×3 factorial experiment design. Results The R value was lower in the intraperitoneal injection than in the subcutaneous injection and intragastric administration groups, and so was it in the 50% than in the 30%CCL4 group, decreasing with the extending of dosing time, with statistically significant differences in the main effects ( P<0.05) as well as a remarkable correlation among drug concentrations, dosing methods, and dosing time (P<0.05).The L value was higher in the intraperitoneal injection than in the subcutaneous injection and intra-gastric administration groups, and so was it in the 50% than in the 30% CCL4 group and in the 12 wk than in the 10 wk and 8 wk groups, with statistically significant differences in the main effects ( P<0.05) but no remarkable correlation among drug concentrations, dosing methods, and dosing time ( P>0.05) .The death rate showed an increasing trend in the intraperitoneal injection, subcutaneous injection and intragastric administration of 30% CCL4 (25.33%, 37.78%, and 38.37%) and 50% CCL4 (42.97%, 47.85%, and 51.88%), higher in the 50%than in the 30%CCL4 .However, no significant differences were found in the survival curves among differ-ent dosing methods or between different drug concentrations (P>0.05). Conclusion Intraperitoneal injection was better than subcu-taneous injection and intragastric administration of CCL4 in inducing liver cirrhosis, and the three dosing methods all showed progressively improved efficiency of modeling with the increase of drug concentration and dosing time.

Digital intraoral scanning is a hot topic in the field of oral digital technology.In recent years,digital intra-oral scanning has gradually become the mainstream technology in orthodontics,prosthodontics,and implant dentistry.The precision of digital intraoral scanning and the accuracy and stitching of data collection are the keys to the success of the impression.However,the operators are less familiar with the intraoral scanning characteristics,imaging process-ing,operator scanning method,oral tissue specificity of the scanned object,and restoration design.Thus far,no unified standard and consensus on digital intraoral scanning technology has been achieved at home or abroad.To deal with the problems encountered in oral scanning and improve the quality of digital scanning,we collected common expert opin-ions and sought to expound the causes of scanning errors and countermeasures by summarizing the existing evidence.We also describe the scanning strategies under different oral impression requirements.The expert consensus is that due to various factors affecting the accuracy of digital intraoral scanning and the reproducibility of scanned images,adopting the correct scanning trajectory can shorten clinical operation time and improve scanning accuracy.The scanning trajec-tories mainly include the E-shaped,segmented,and S-shaped methods.When performing fixed denture restoration,it is recommended to first scan the abutment and adjacent teeth.When performing fixed denture restoration,it is recommend-ed to scan the abutment and adjacent teeth first.Then the cavity in the abutment area is excavated.Lastly,the cavity gap was scanned after completing the abutment preparation.This method not only meets clinical needs but also achieves the most reliable accuracy.When performing full denture restoration in edentulous jaws,setting markers on the mucosal tissue at the bottom of the alveolar ridge,simultaneously capturing images of the vestibular area,using different types of scanning paths such as Z-shaped,S-shaped,buccal-palatal and palatal-buccal pathways,segmented scanning of dental arches,and other strategies can reduce scanning errors and improve image stitching and overlap.For implant restora-tion,when a single crown restoration is supported by implants and a small span upper structure restoration,it is recom-mended to first pre-scan the required dental arch.Then the cavity in the abutment area is excavated.Lastly,scanning the cavity gap after installing the implant scanning rod.When repairing a bone level implant crown,an improved indi-rect scanning method can be used.The scanning process includes three steps:First,the temporary restoration,adjacent teeth,and gingival tissue in the mouth are scanned;second,the entire dental arch is scanned after installing a standard scanning rod on the implant;and third,the temporary restoration outside the mouth is scanned to obtain the three-di-mensional shape of the gingival contour of the implant neck,thereby increasing the stability of soft tissue scanning around the implant and improving scanning restoration.For dental implant fixed bridge repair with missing teeth,the mobility of the mucosa increases the difficulty of scanning,making it difficult for scanners to distinguish scanning rods of the same shape and size,which can easily cause image stacking errors.Higher accuracy of digital implant impres-sions can be achieved by changing the geometric shape of the scanning rods to change the optical curvature radius.The consensus confirms that as the range of scanned dental arches and the number of data concatenations increases,the scanning accuracy decreases accordingly,especially when performing full mouth implant restoration impressions.The difficulty of image stitching processing can easily be increased by the presence of unstable and uneven mucosal mor-phology inside the mouth and the lack of relatively obvious and fixed reference objects,which results in insufficient ac-curacy.When designing restorations of this type,it is advisable to carefully choose digital intraoral scanning methods to obtain model data.It is not recommended to use digital impressions when there are more than five missing teeth.