BACKGROUND:Stem cel is a kind of pluripotent cels with self-replication ability, which can differentiate into various cels under certain conditions. Furthermore, stem cels are rich in a variety of growth factors, which can induce the generation of vessels and nerves, and improve the blood supply of lower limbs, thereby achieving the treatment and preventions of lower limb ischemia OBJECTIVE:To summarize and compare the recent achievements in the theory and therapeutic efficacy of stem cels from different sources in the treatment of diabetic foot. METHODS:The first and second authors retrieved PubMed, Sciencedirect and Medline databases for relevant articles published from January 2000 to January 2015. The key words were “diabetic foot, pathogenesis, stem cel therapy” in English. Initialy, 186 articles were retrieved, and finaly 44 articles were included in result analysis. RESULTS AND CONCLUSION:Stem cels can be a new choice for the treatment of diabetic foot. After stem cel therapy, corresponding symptoms have been aleviated, including the generation of new blood vessels and the reshaping of the colateral vessels, the improvement of motor nerve conduction velocity and nerve reflex, the improvement of the sense of skin pain and temperature, and pain relief. It is stil unclear whether alogeneic stem cels are safe or not, but autologous stem cels, especialy bone marrow mesenchymal stem cels, can be better able to repair damaged vessels and nerves and restore the microcirculation of blood supply. Currently, we need to do more basic and clinical researches to solve the folowing problems: to confirm the effectiveness and safety of stem cel therapy for diabetic foot; to identify whether there is a difference in the differentiation and secretory activity between stem cels in diabetic patients and ordinary people; to give ful play to the treatment of diabetic foot.

Immunosuppressants, which are commonly used for liver transplantation, mainly included calcineurin inhibitors, such as ciclosporin (CsA) and tacrolimus (FK506); glucocorticoid drugs, such as prednisone and prednisolone; cytotoxic drugs, such as azathioprine, mycophenolate mofetil and cyclophosphamide; mammalian target of rapamycin (mTOR) inhibitors, such as sirolimus and everolimus; antibody drugs, such as polyclonal or monoclonal antibodies and interleukin (IL)-2 receptor antibodies, etc. Although many categories of immunosuppressants are available, FK506 is the most commonly adopted in liver transplant recipients. However, FK506 can provoke significant adverse effects in the late stage of liver transplantation, especially severe infection and nephrotoxicity. Consequently, it is an urgent task and research hot spot to develop new immunosuppressants with strong immune tolerance and mild adverse effects in clinical practice. In this article, the research progress on immunosuppressants and the research and development status of new immunosuppressants for liver transplantation were reviewed.

Objective To summarize the MRI characteristics of fat-containing hepatocellular carcinoma (HCC).Methods The retrospective cross-sectional study was conducted.The clinicopathological data of 18 patients with fat-containing HCC who were admitted to the Eastern Hepatobiliary Surgery Hospital of the Second Military Medical University between January 2015 and April 2016 were collected.All patients underwent MRI examination.Observation indicators:(1) imaging examination;(2) pathological features;(3) treatment and follow-up.Follow-up using outpatient imaging examination was performed to detect tumor recurrence once at 1 month postoperatively and once every 3 months postoperatively up to December 2016.Measurement data with normal distribution were represented as-x±s.Results (1) Imaging examination:plain scans of MRI:of 18 patients,lesions of 9,7 and 2 patients were respectively located in left,right and caudate lobes of liver,and lesions were round-like,with a diameter of 1.6-9.0 cm.Tumors were single,and tumor thrombosis in the hepatic vein was seen in 1 patient.T2WI on fat-suppression of 15 and 3 patients showed respectively high signals and iso-signal;MRI examination showed that out-phase signal on T1WI was variously decreased than in-phase signal,showing focal or diffuse signal decreasing;lipid phase on T1WI showed diffuse distribution in 10 patients,patchy fat-containing regions were scattered within the peritumoral zone in 7 patients,and lipid of 1 patient was located in the central area.Dynamic contrast enhancement MRI showed that fast-in and fast-out,fast-in and slow-out,and slow-in and slow-out types were detected in 16,1 and 1 patients,respectively.Sixteen patients had capsule-like enhancement in delayed phase.Diffusion weighted imaging (DWI) showed high signals in 10 patients,slightly high signals in 6 patients and iso-signal in 2 patients.Apparent diffusion coefficient (ADC) value was (1.19± 0.20)×10-3 mm2/s,including (1.37±0.20) × 10-3 mm2/s in lipid-rich type,(1.17±0.13) × 10-3 mm2/s in clear cell type and (1.11±0.17)× 10-3 mm2/s in thick beam type.Of 18 patients,2 were preoperatively misdiagnosed as hepatic angiomyolipoma and 1 as hepatic adenoma.(2) Pathological features:pathological types of 18 patients with fat-containing HCC:5 and 13 patients were respectively in lipid-rich and non-lipid-rich types (4 in clear cell type and 9 in thick beam type);steatosis tumor cells,rich and translucent cytoplasms and large vacuolated lipid droplets were seen under the microscope;steatosis tumor cells were diffused or scattered within the lesions,some of which showed plaque-like performance of different sizes.Degree of microvascular invasion:grade M0,M1 and M2 were found in 12,3 (2 in thick beam type and 1 in clear cell type) and 3 (2 in thick beam type and 1 in lipid-rich type) patients,respectively.(3) Treatment and follow-up:18 patients underwent surgery and were followed up for 6-13 months,with a median time of 8 months.During the follow-up,5 patients in lipid-rich type and 4 in clear cell type had no recurrence;among 9 patients in thick beam type,1 of 4 with microvascular invasion had no recurrence,2 and 1 of 4 with microvascular invasion had respectively recurrence at 3 months postoperatively and 4 months postoperatively,and 5 without microvascular invasion had no recurrence.The lesions of 3 patients with recurrence is single,3 patients received local minimally invasive therapy and continuous follow-up.Conclusion MRI characteristics of fat-containing HCC include that decreased out-phase signal on T1WI compared with in-phase signal,high signal on DWI,low ADC value,fast-in and fast-out enhancement and capsule-like enhancement in delayed phase.

End-stage liver disease (ESLD) is a serious threat to human health, and liver transplantation is the only effective treatment. However, most of the patients died in the process of waiting for transplantation due to the shortage of liver source. With the rapid development of biological tissue enginee-ring technology, researchers have established the strategy of 'decellularized and recellularized technology’, which has deve-loped into the first choice for construction of important organs such as the liver and opened up new ideas for the treatment of ESLD. At present, scientists are working on the optimization of this technology, in order to construction a functional 'new liver’ for transplantation. The authors review the feasibility and challenges of the application of this technology and its optimization stra-tegy in the field of regenerative surgery.