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Limb loss experience is a type of body illusion characterized by the sensation of a missing limb or body part. We aimed to investigate the brain areas involved in this unusual somatosensory experience evoked by electric cortical stimulation with stereo-electroencephalography electrodes. We retrospectively reviewed the data of patients with medical intractable epilepsy, from October 2015 to December 2020, who underwent stereo-electroencephalography implantation and electric cortical stimulation in order to locate the epileptogenic zone and obtain a functional map. We included patients who reported experiences of limb loss during the process of electric cortical stimulation for functional mapping. Three patients reported experiences of limb loss in the process of electric cortical stimulation. Limb loss experience (including the right hand, right upper limb and right side of the body) occurred when the cortex of the left posterior insula, posterior dorsal cingulate and parietal operculum were stimulated. Limb loss experience can be evoked by electric cortical stimulation of the posterior insula, parietal operculum, and posterior cingulate cortex, and provides additional evidence that these cortices play a role in the integration of body sensory perception.

To compare the immunosuppressive effects of maternal and fetal placental mesenchymal stem cells (mPMSCs and fPMSCs, respectively) on the rejection of allogenic skin transplants in mice, and further to investigate the mechanism underlying this suppression.The mPMSCs and fPMSCs were isolated from human term placentas. The expressions of cell surface markers were detected by flow cytometry. Cell proliferation capacity was characterized by MTT colorimetric assay. CD200 protein expressed on fPMSCs was neutralized with streaming monoclonal antibodies, and mPMSCs were infected with adenovirus expression vector carrying CD200 cDNA. For skin transplantation, 60 C57BL/6 mice were randomly divided into 6 groups as skin transplant recipients, and ICR mice served as skin donors. After establishment of the allogenic skin transplants, recipient mice of the 6 groups were intravenous injected respectively with PBS, mPMSCs, fPMSCs, fPMSCs combined with anti-CD200 antibodies, mPMSCs with CD200 expressing vectors, and mPMSCs with empty vectors. The conditions and survival time of the skin grafts were inspected daily, and the expressions of interleukin 17 (IL-17), interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and interleukin 12 (IL-12) in blood and spleen were measured at the end of the study by ELISA and reverse transcription PCR.The majority (70%) of fPMSCs were detected CD200 positive, while only a minor fraction (about 2%) of CD-200 positive cells were seen in mPMSCs. In the allogenic skin graft mice, the graft survival time in both mPMSCs- and fPMSCs-treated groups were significantly longer than that in PBS group [(5.6±1.17) days], while the fPMSCs group [(10.6±1.43) days] was more dominant than mPMSCs group [(7.7±1.42) days]. Neutralizing anti-CD200 antibody reduced the graft survival [(8.2±1.14) days] of the fPMSCs group to the level of that in mPMSCs group, while enforced expression of CD200 increased the graft survival [(10.7±1.34) days] of the mPMSCs group to the level of the fPMSCs group. The empty vector-transfected mPMSCs showed a similar effect on graft survival [(7.8±1.32) days] as that in mPMSCs group, longer than PBS group but shorter than fPMSCs and mPMSCs combined with CD200 groups. Comparing with PBS group, the expressions of IL-17, IFN-γ and TNF-α were significantly reduced in mPMSCs and fPMSCs groups. The reduction of these cytokine expressions in the fPMSCs group was neutralized when anti-CD200 antibody was applied, while this reduction in the mPMSCs-treated mice was further enhanced when the mPMSCs were enforced to express CD200.The immunosuppressive effect of fPMSCs on the rejection of allogenic skin transplantation was higher than that of mPMSCs, and this difference was partially contributed by CD200 signaling pathway. The mechanism of this suppression may mediate the inhibition of IL-17, IFN-γ, TNF-α and IL-12 expressions. The fPMSCs may be a suitable choice for immunosuppression on skin transplantation.

Introduction Therapeutic potentials of mesenchymal stem cells (MSCs) from different sources have been evaluated in pre-clinical and clinical settings. Although MSCs from different sources share MSC-specific characteristics and functions, inconsistent or controversial results of pre-clinical and clinical applications of such cells are frequently reported. This may be partially due to the fact that MSCs isolated from different origins may differentially express some functions not typical for MSCs, and hence have different therapeutic potentials. The aim of this study is to investigate the differences in human placental MSCs (P-MSCs) of fetal and maternal origins in the aspects of clinical importance. Methods P-MSCs of fetal and maternal origins isolated from normal term placentas were characterized for their typical phenotype as well as their expression of receptors and growth factors of clinic interests. P-MSCs that preferentially express hepatocyte growth factor (HGF) and CD200 were evaluated for their therapeutic potentials in models of angiogenesis and allogeneic skin transplantation, in comparison with their HGF and CD200 negative partners. Results Although all P-MSCs express typical MSC phenotype, fetal but not maternal P-MSCs express high levels of CD200 and HGF. Compared with HGF and CD200 negative P-MSCs, HGF and CD200 positive cells demonstrated significantly high potentials in promoting angiogenesis in vitro and increasing immunosuppressive function in vivo. These therapeutic potentials were at least in part due to their differences in HGF and CD200 expression, respectively. Conclusions We conclude that MSC origins may have significant impact on the therapeutic potentials of such cells, and should be taken into consideration in clinical applications.