BACKGROUND: The development of cartilage tissue engineering provides novel ideas for treatment of articular cartilage defects and implements construction of tissue-engineered cartilage in vivo.OBJECTIVE: To investigate the feasibility of constructing tissue-engineered osteochondral composite through bone marrow stem cells(BMSCs) cultured on the poly(lactide-co-glycolic acid) (PLGA), which was modified with collagen and cellular growth factors.METHODS: PLGA was made by phase separation technique, composited with collagen Ⅱ, basic fibroblast growth factor, and transforming growth factor-β1. The BMSCs of passage 3 were cultured on the above scaffolds. Thirty-six SD rats were randomly divided into experimental, control, and blank groups. These three groups received implantation of BMSCs composited with growth factors and collagen-PLGA, implantation of BMSCs composited with collagen-PLGA, and implantation of collagen-PLGA into the muscle, respectively. At 4, 8, and 12 weeks after surgery, cell directional differentiation and growth were examined by gross observation, hematoxylin-eosin staining, toluidine blue staining, collagen Ⅱ staining, and scanning electron microscope.RESULTS AND CONCLUSION: Gross observation showed that there were many chondroid tissues in the experimental group and fibrous tissues in the control and black groups. Stainings and electron microscope revealed that many chondroblasts and a few osteoclasts appeared in the composite of the experimental group. Toluidine blue and collagen Ⅱ stainings were positive in the experimental group and negative in the control and blank groups. These findings demonstrate that PLGA modified with collagen had a good cellular compatibility. BMSCs cultured on PLGA, which was modified with collagen and cellular growth factors, can construct the tissue-angineered osteochondral composite in rats.

BACKGROUND: Though there were many experiments addressing repairing osteochondral defects before, faulty restoration occurred at coupling interfaces. OBJECTIVE: To investigate the feasibility of repairing of osteochondral composite defects in rabbit knees with animal-origin osteochondral scaffold combined with bone marrow mesenchymal stem cells (BMSCs)/chondrocytes.METHODS: New Zealand white rabbits were randomly divided into the experimental, control and blank groups and prepared for unilateral knee joint osteochondral defects. Animal-origin osteochondral scaffold combined with BMSCs/chondrocytes, animal-origin osteochondral scaffold and no material was implanted to repair the defects in the experimental, control and blank groups, respectively. Healing condition was evaluated by gross observation, hematoxylin-eosin staining, and toluidine blue staining at 4, 8, and 12 weeks after operation. RESULTS AND CONCLUSION: At 12 weeks after operation, gross observation showed the defects were repaired completely without local depression and the regenerated tissues were fused with surrounding tissues in the experimental group. Hematoxylin-eosin staining and toluidine blue staining revealed that there were many new hyaline cartilages in the cartilage defects in which columnar cells were lined well and cartilage lacuna was obviously, also, there were many bony tissues in the bone defects. The regeneration cartilage, the underlying subchondral bone and host bone were coupled completely. The toluidine blue positive rate and histologic scores of the experimental group were superior to those of the control and blank groups (P < 0.05). It is demonstrated that animal-origin osteochondral scaffold combined with BMSCs/chondrocytes is an ideal method to repair defects between cartilage and the underlying subchondral bone.

Objective:To measure the change in Young′s modulus of the biceps brachii during passive stretching and to assess the potential of shear wave elastography (SWE) as an auxiliary quantitative technique for assessing muscle tone.Methods:Forty-nine stroke survivors and 30 healthy subjects were evaluated using the modified Ashworth scale (MAS). According to their MAS scores they were divided into a healthy group, a healthy elbow group, an MAS class-0 group, an MAS class-1 group, an MAS class-1 + group and an MAS class-2 group. During passive extension of the subjects′ elbows, shear wave elastography was used to image the biceps brachii. Six points of the elbow were selected to record the instantaneous Young′s modulus ( EX) and calculate its change during the movement (Δ E). Those data were correlated with the MAS scores and compared among the groups. Results:Persons with higher MAS scores tended to have a higher Young′s modulus of the biceps brachii, and the modulus was likely to increase more with increases in the angle of elbow extension. From half of the range of motion to full extension there were significant differences in EX and Δ E between MAS class-0 and class-1 groups, as well as between the class-0 and class-1 + groups. There were, however, no significant differences between MAS class-1 and MAS class-1 + . Conclusions:MAS scores can usefully predict biceps brachii stiffness during passive elbow flexion. Shear wave elastography can quantify that stiffness and also muscle tone.

Under the combination of postgraduate education and standardized medical residents training, via exploring current situation, we put forward the limitations of routine rotation training, disconnection of theory and practice, inefficient of scientific ability. We arouse a new model by improving teaching model, enriching teaching content, optimizing teaching method, making better arrangement of rotations and cultivating scientific ability to provide references for enhancing the ability of clinical thinking, practice, scientific research and communication.

Objective:To explore the application effects of the mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice" in the teaching of spinal surgery.Methods:A total of 64 eight-year program clinical medical students who practiced in Peking Union Medical College Hospital in 2021 were taken as research objects and randomly divided into experimental group ( n=33) and control group ( n=31). The experimental group received the new teaching mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice", and the control group received regular teaching mode. At the end of teaching, the teaching effects were evaluated from several aspects, including the scores of theoretical examinations, anatomical marks identification tests, and anonymous questionnaires. SPSS 22.0 software was used for paired t-test and two independent-samples t-test. Results:The theoretical test scores [(51.25±6.99) points] and anatomical structure identification scores [(37.56±1.83) points] of the experimental group were higher than those of the control group [(42.46±6.13) points and (30.37±3.46) points], and the differences were statistically significant ( P<0.001). The effective recovery rate of the questionnaire was 100%. The results of the questionnaire showed that the experimental group was significantly higher than the control group in terms of teaching attractiveness, attention, learning interest, learning efficiency, anatomical identification ability, problem-finding and problem-solving ability and overall teaching method satisfaction ( P<0.05). Conclusion:The teaching mode of "Multidisciplinary integration, Doctors & patients co-teaching, Simulated practice" can effectively improve students' theoretical knowledge, learning interest, learning efficiency, operation proficiency and problem-finding and problem-solving ability, which is worth promoting.

Objective:To observe the clearance strategies of hemiplegic stroke survivors with foot drop.Methods:Thirty hemiplegic stroke survivors with foot drop formed the observation group and 30 healthy counterparts constituted the control group. A three-dimensional motion capture system was used to observe and compare the minimum toe clearance (MTC) and its variability between the two groups to draw the motion trajectory of the toe in the swing phase of their gaits. The gait parameters were correlated with the toe clearance.Results:The average MTC of the observation group subjects on both the hemiplegic and non-hemiplegic side (12.01±3.36 and 22.38±5.51mm) was significantly smaller than the control group′s averages. The variability of their MTCs on both sides was also significantly greater. Clearance on the hemiplegic side was significantly less and its variability was significantly greater. Among the observation group, MTC on the hemiplegic side was positively correlated with walking speed, step length, swing phase percentage, maximum angle of hip extension, maximum angle of knee flexion, maximum angle of ankle dorsiflexion, and the range of motion of the knee and ankle joints.Conclusions:Hemiplegic stroke survivors with foot drop walk unstably with little toe clearance. It is necessary to intervene at the hip, knee and ankle to improve their obstacle clearance.

To observe the migration of human amniotic mesenchymal stem cells (hAMSCs) labeled with PKH26 in the endometrium of rats intrauterine adhesion. hAMSCs were isolated, identified and labeled with PKH26 to detect the biological characteristics of the cells. Rat intrauterine adhesion models were established using mechanical and infective method and PKH26-labeled hAMSCs were transplanted through the tail vein. The distribution of PKH26 labeled hAMSCs in the endometrium of rats were observed with the fluorescence confocal microscope. The results showed that PKH26 stain had no significant effect on cell activity, cycle, apoptosis and so on. PKH26-labeled positive cells were mainly distributed in injured endometrium of rats. It shows that the PKH26 labeling technique is a safe and effective method for tracing the human amniotic mesenchymal stem cells in the treatment of intrauterine adhesions.

In this study, we explored the neural mechanism underlying impaired stereopsis and possible functional plasticity after strabismus surgery. We enrolled 18 stereo-deficient patients with intermittent exotropia before and after surgery, along with 18 healthy controls. Functional magnetic resonance imaging data were collected when participants viewed three-dimensional stimuli. Compared with controls, preoperative patients showed hypoactivation in higher-level dorsal (visual and parietal) areas and ventral visual areas. Pre- and postoperative activation did not significantly differ in patients overall; patients with improved stereopsis showed stronger postoperative activation than preoperative activation in the right V3A and left intraparietal sulcus. Worse stereopsis and fusional control were correlated with preoperative hypoactivation, suggesting that cortical deficits along the two streams might reflect impaired stereopsis in intermittent exotropia. The correlation between improved stereopsis and activation in the right V3A after surgery indicates that functional plasticity may underlie the improvement of stereopsis. Thus, additional postoperative strategies are needed to promote functional plasticity and enhance the recovery of stereopsis.
Humans ; Exotropia/surgery* ; Depth Perception/physiology* ; Strabismus/surgery* ; Oculomotor Muscles/surgery*

Aging associated cognitive decline has been linked to dampened neural stem/progenitor cells (NSC/NPCs) activities manifested by decreased proliferation, reduced propensity to produce neurons, and increased differentiation into astrocytes. While gene transcription changes objectively reveal molecular alterations of cells undergoing various biological processes, the search for molecular mechanisms underlying aging of NSC/NPCs has been confronted by the enormous heterogeneity in cellular compositions of the brain and the complex cellular microenvironment where NSC/NPCs reside. Moreover, brain NSC/NPCs themselves are not a homogenous population, making it even more difficult to uncover NSC/NPC sub-type specific aging mechanisms. Here, using both population-based and single cell transcriptome analyses of young and aged mouse forebrain ependymal and subependymal regions and comprehensive "big-data" processing, we report that NSC/NPCs reside in a rather inflammatory environment in aged brain, which likely contributes to the differentiation bias towards astrocytes versus neurons. Moreover, single cell transcriptome analyses revealed that different aged NSC/NPC subpopulations, while all have reduced cell proliferation, use different gene transcription programs to regulate age-dependent decline in cell cycle. Interestingly, changes in cell proliferation capacity are not influenced by inflammatory cytokines, but likely result from cell intrinsic mechanisms. The Erk/Mapk pathway appears to be critically involved in regulating age-dependent changes in the capacity for NSC/NPCs to undergo clonal expansion. Together this study is the first example of using population and single cell based transcriptome analyses to unveil the molecular interplay between different NSC/NPCs and their microenvironment in the context of the aging brain.
Aging ; genetics ; Animals ; Astrocytes ; cytology ; metabolism ; Brain ; cytology ; metabolism ; Cell Differentiation ; genetics ; Cell Division ; genetics ; Cell Proliferation ; genetics ; Gene Expression Regulation ; genetics ; Mice ; Neural Stem Cells ; metabolism ; Single-Cell Analysis ; Stem Cells ; cytology ; metabolism ; Transcriptome ; genetics

The mammalian brain is heterogeneous, containing billions of neurons and trillions of synapses forming various neural circuitries, through which sense, movement, thought, and emotion arise. The cellular heterogeneity of the brain has made it difficult to study the molecular logic of neural circuitry wiring, pruning, activation, and plasticity, until recently, transcriptome analyses with single cell resolution makes decoding of gene regulatory networks underlying aforementioned circuitry properties possible. Here we report success in performing both electrophysiological and whole-genome transcriptome analyses on single human neurons in culture. Using Weighted Gene Coexpression Network Analyses (WGCNA), we identified gene clusters highly correlated with neuronal maturation judged by electrophysiological characteristics. A tight link between neuronal maturation and genes involved in ubiquitination and mitochondrial function was revealed. Moreover, we identified a list of candidate genes, which could potentially serve as biomarkers for neuronal maturation. Coupled electrophysiological recording and single cell transcriptome analysis will serve as powerful tools in the future to unveil molecular logics for neural circuitry functions.
Antigens, Differentiation ; biosynthesis ; Electrophysiological Phenomena ; physiology ; Gene Expression Regulation ; physiology ; Genome-Wide Association Study ; Human Embryonic Stem Cells ; cytology ; metabolism ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; Multigene Family ; physiology ; Neurons ; cytology ; metabolism ; Transcriptome ; physiology