Dianying Zhang

Bone marrow stromal cells differentiated into functional Schwann cells in injured rats sciatic nerve.

Bone marrow stromal cells (MSCs) have been shown to differentiate into various lineage cells including neural cells in vitro and in vivo. We therefore examined whether MSCs can differentiate into Schwann cells in injured peripheral nerves. After cultured in vitro, PKH-67-labeled MSCs were injected into the mechanically injured rat sciatic nerves. Three weeks after injection, immunofluorescent examinations were carried out. MSCs had been incorporated around the injured nerves and differentiated into Schwann cells. MSCs had accumulated mainly in the epineurium around the injured nerve. The incorporated cells partially expressed GFAP, S-100, and P75. These results confirmed the possibility that MSCs have the ability to differentiate into Schwann cells, and that injection of MSCs into the injured peripheral nerve would help repair damaged nerve.

Effect of Calcar Screw Use in Surgical Neck Fractures of the Proximal Humerus With Unstable Medial Support: A Biomechanical Study.

Objectives: To evaluate the effect of calcar screw use in proximal humeral fractures with unstable medial support treated with locked plates. Methods: Standard osteotomies were performed in 36 cadaveric humeri to create a surgical neck fracture proximal humeral model. For static testing, 12 pairs of humeri were divided into 4 groups: normal alignment and varus deformity groups with and without 5-mm medial deficiencies. Calcar screw function was measured in each group by axial, shear, and torsion stiffness tests. Another 6 pairs of humeri with 5-mm medial deficiencies were subjected to cyclic loading tests in the normal alignment model with and without calcar screw application. Results: Calcar screws improved rotational stability in the normal alignment (P = 0.007) and varus (P = 0.002) groups. Calcar screws improved static and cyclic axial (P = 0.004) and shear (P = 0.017) stability in the normal alignment group with medial deficiency. In specimens with normal alignment and intact medial cortex, calcar screws provided no advantage in axial (P = 0.535) or shear (P = 0.537) stiffness. Calcar screws did not provide sufficient axial (P = 0.782) or shear (P = 0.772) stability to avoid reduction loss in humeri with varus malreduction. Conclusions: In humeri with normal alignment, calcar screws can provide additional stability even when a medial deficiency exists. The use of calcar screws in humeri with varus deformity showed no biomechanical superiority.

The Experimental Study of Absorbable Chitin Conduit for Bridging Peripheral Nerve Defect with Nerve Fasciculu in Rats

To investigate the possibility of constructing artificial peripheral nerves using de-acetyl chitin conduit, the sciatic nerves defect model was built at left legs in SD rats. They were divided into 3 groups randomly: group A: nerve graft in situ (n = 12, gap distance 10 mm); group B: biological chitin conduit bridging the peripheral nerve defect (n = 12, gap distance 10 mm); group C: biological chitin conduit bridging the peripheral nerve defect with nerve fibers in conduits (n = 12, gap distance 10 mm). Electrophysiological examination, histological examination and re-myelinated axons counting were applied after 6th and 12th week after operation, respectively. Regenerated nerve fibers were seen in the distal nerve segments of all three groups. The nerve conduction velocity and the re-myelinated axons counting of group A were better than that of group C at both 6th and 12th week time points (p < 0.05). The nerve conduction velocity and the re-myelinated axons counting of group C were better than that of group B at both 6th and 12th week time points (p < 0.05). The repair effects of chitin conduit with nerve fibers in conduit bridging peripheral nerve defect (10 mm) were better than that of simple conduit bridging group, and that of group A (nerve graft group) was better than that of group C.

Effects of Hedysari Polysaccharides on Regeneration and Function Recovery Following Peripheral Nerve Injury in Rats

It has been demonstrated that aqueous extract of Radix Hedysari Prescription and modified Radix Hedysari Prescription could improve the regeneration of injured peripheral nerve. Radix Hedysari is a main component in these two formulas. We hypothesized that Hedysari polysaccharides (HPS), a main active ingredient, could also enhance peripheral nerve regeneration after nerve injury in adult animals. In the present study, we examined the effects of HPS on sciatic nerve regeneration for 6 weeks following clamping in rats (administrated orally of 2 ml HPS liquid daily, 0.25 g/ml). The results showed that HPS was able to enhance sciatic function index (SFI) value, tibial function index (TFI) value, peroneal nerve function index (PFI) value, conduction velocity, and the number of regenerated myelinated nerve fibers, suggesting the potential clinical application of HPS for the treatment of peripheral nerve injury in humans.

The Influence of Brain Injury or Peripheral Nerve Injury on Calcitonin Gene-Related Peptide Concentration Variation and Fractures Healing Process

To investigate the changes of calcitonin gene-related peptide (CGRP) in rats blood plasma, spinal anterior motorneuron, and dorsal root ganglion (DRG) after fractures combined with central or peripheral nerve injuries and its influence on fracture healing, 72 healthy adult SD rats (male or female) were divided into 4 groups (18 rats in each group): group A, simple(left) tibial fracture; group B, left tibial fracture combined with left sciatic nerve injury; group C, left tibial fracture combined with T9-11 spinal cord transection injury; group D, left tibial fracture combined with right cerebral cortex injury. Group A was the control group. The concentration of serum CGRP was measured immediately, 1w, 2w, and 4w after injury using radio immunoassay. X-ray photograph was taken at 1w, 2w, and 4w after injury to assess fracture healing. The concentration of serum CGRP in spinal anterior motorneuron and dorsal root ganglion was measured 1w, 2w, and 4w after injury. Bony callus at 2w after injury using H.E.staining was observed. 1w and 2w after injury, the fracture line was still clear on the X-ray of all groups, but 4w after injury the fracture line disappeared with complete healing except the peripheral nerve injury group. By H.E. staining, we found lesser bony callus contents in the peripheral nerve injury group than the simple fracture group at 2w after injury; irregular bone trabecula and healing defect were found in the former group. While the spinal injury group and cerebral cortex injury group represented more bony callus than the simple fracture group, increased bone trabecula and regularity, medullary cavity occluded and finally solid bony connections were found. CGRP concentration in blood plasma and spinal anterior motorneuron represented no apparent differences among all groups during each observation period. For the dorsal root ganglion group, 1w after fracture, there was no apparent difference of CGRP concentration in the peripheral nerve injury group and cerebral cortex group compared with the control group (P > 0.05), but the spinal injury group showed more CGRP than the control group (P < 0.01). 2w after injury, the peripheral nerve injury group and cerebral cortex group also showed no difference compared with the control group, but the cerebral cortex group had more CGRP contents than the peripheral nerve injury group (P < 0.05), and the spinal injury group showed more CGRP than the control group (P < 0.01). 4w after injury, the peripheral nerve group, spinal injury group, and cerebral cortex injury group all showed higher concentration of CGRP than the control group. Among the 3 groups, the spinal injury group is the highest (P < 0.01). When fracture combined with peripheral nerve injury, the healing process can be slowed down. In contrast, fracture combined with spinal injury and cerebral cortex injury will accelerate the healing process. The CGRP in dorsal root ganglion in spinal injury group and cerebral cortex injury group increased, which may have positive effects on fracture healing.

Incidence of venous thromboembolism and hemorrhage related safety studies of preoperative anticoagulation therapy in hip fracture patients undergoing surgical treatment: a case–control study

BackgroundVenous thromboembolism is a common postoperative complication following orthopedic surgeries, with morbid and potentially fatal consequences. Perioperative low-molecular-weight heparin (LMWH) therapy can reduce the incidence of venous thromboembolism, but may also increase the risk of bleeding complications. Current literature reflects the need to balance the improved efficacy of early initiating prophylaxis with increased risk of perioperative bleeding. The purpose of this study was to compare the effectiveness and hemorrhage related safety of preoperative versus postoperative LMWH therapy for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in hip fracture patients.MethodsWe retrospectively evaluated 222 patients who underwent surgical treatment at Peking University Peoples Hospital between January 2009 and December 2010. Patients were allocated to two groups, receiving either preoperative or postoperative initiation of LMWH therapy for venous thromboembolism prophylaxis. Preoperative anticoagulation therapy was initiated 1–12 days prior to surgery (133 patients), and postoperative anticoagulation therapy was initiated 12 h after completion of surgery (89 patients). The preoperative group was further subdivided into four subgroups according to the time of initiation of therapy: 1–3 days before surgery (group A, 54 patients), 4–6 days before surgery (group B, 57 patients), 7–9 days before surgery (group C, 15 patients), and 10–12 days before surgery (group D, 7 patients). Occurrences of DVT, PE, adverse drug effects, intraoperative and postoperative bleeding were recorded, along with concentrations of preoperative and postoperative hemoglobin and length of hospital stay. The above parameters were compared between groups.ResultsAmong recipients of preoperative anticoagulation therapy, two patients developed postoperative PE (1.5 %), one patient developed DVT (0.75 %). In the group receiving postoperative initiation of anticoagulation therapy, one patient each developed PE and DVT (1.1 %, 1.1 %). There was no difference in the occurrence of PE and DVT between the two groups (P>0.05, Chi-square tests). We identified the incidences of major bleeding, minor bleeding, and intraspinal hematoma after spinal anesthesia, which were 0 %/0 %, 3.76 %/3.37 %, and 0 %/0 %, respectively in preoperative and postoperative anticoagulation groups. There was no significant difference in the incidence of bleeding complications between patients receiving preoperatively initiated LMWH with patients receiving postoperatively initiated LMWH. Spinal anesthesia was administered to 168 patients, with no cases of postoperative intraspinal hematoma.ConclusionsPreoperative anticoagulation therapy with LMWH may not increase intraoperative or postoperative blood loss, or the rate of intraspinal hematoma after spinal anesthesia, but also does not significantly reduce the risk of postoperative DVT or PE, compared to postoperative initiation.

Comparison of Road Traffic Injury Characteristics between Local versus Floating Migrant Patients in a Tertiary Hospital between 2007 and 2010

Background The aim of this study is to give a description of the road traffic injuries (RTIs) characteristics of floating migrant population by comparing with those of local residents in a harbor city of China. Methods A population-based descriptive study was carried out between 2007 and 2010 with RTI patient records from the Fifth Center Hospital of Tianjin. Inpatient diagnoses of RTI patients were defined using the International Classification of Diseases, Tenth Revision (ICD-10) codes. We analyzed the demographics and general characteristics of RTI patients that were in the hospital during the four years. In order to compare the group differences between local resident patients and floating migrant patients, the distribution of their ages, diagnoses, severity of injuries, duration of inpatient stays, hospitalization cost were analyzed. Results People between the ages of 16 and 55 were the most likely to suffer RTIs. The floating migrant patients between the ages of 16 and 45 had a higher incidence of accidents, while local resident patients between 46 and 55 had a higher incidence of accidents. Compared to local resident patients, floating migrant patients were more vulnerable to open injuries and severe traffic injuries. With the severity of injuries ranked from mild to severe, floating migrant patients had lower duration of inpatient stay, but higher hospitalization costs compared to local resident patients. Conclusions Floating migrant patients had a different age distribution, severity of injuries, diseases, inpatient duration and hospitalization cost compared with local resident patients. Compared to local resident patients, floating migrants had a higher risk to RTIs and were more vulnerable to severer traffic accidents at lower ages.

Biomechanical Evaluation of a New Device for Internal Fixation of Femoral Neck Fractures

Abstract: This study aimed to compare the fixation stability of a new device (SCCAB) for femoral neck fractures and the cancellous lag screws. Standardized femoral neck osteotomies were created in seven pairs of cadaver femurs and stabilized with either SCCAB or cancellous lag screws. The specimens were subjected to incremental axial loading to 1300 N and cyclic loading at 1300 N for 104 cycles. No significant differences in downward femoral head displacement, change in the superior osteotomy gapping, and load to failure were observed between the two groups. SCCAB may be potentially useful to treat femoral neck fractures.

EGFP Expression Controlled by GFAP Promoter in Mesenchymal Cells: An Efficient Tool for Glial Lineage Selection and Transplantation

In order to demonstrate a new method to label and select enough glial cells from induced MSCs to provide cells for cell therapy, MSCs were induced with Beta-mercaptoethanol followed by retinoic acid, forskolin, basic-FGF, PDGF and heregulin. Induced MSCs were transfected with reconstructed vector pGFAP-EGFP by inserting GFAP promotor into pEGFP-N3 to substitute CMV promotor. Living cells against G418 were enriched and checked by flowcytometry. EGFP expressing cells were sorted and used for transplantation in vivo. Immunoelectronmicroscopy was accomplished using anti-EGFP to relocalize the transplanted cells. Almost all MSCs took on phenotypes of glial cells after induction, expressing S100 and GFAP. The EGFP expression rate of survived MSCs against G418 was 82.74%. Glial cells expressing EGFP accumulated mainly around the damaged nerve fibers. MSCs were relocalized by immunoelectronmicroscopy and remyelination was observed. EGFP expression controlled by GFAP promoter in mesenchymal cells was an efficient tool for glial lineage selection and transplantation. Induced MSCs can promote nerve regeneration by participating remyelination.

Evaluation of the Effects of Standard Rescue Procedure on Severe Trauma Treatment in China

Background: This study aimed to evaluate the effects of standard rescue procedure (SRP) in improving severe trauma treatments in China. Methods: This study was conducted in 12 hospitals located in geographically and industrially different cities in China. A standard procedure on severe trauma rescue was established as a general rule for staff training and patient treatment. A regional network (system) efficiently integrating prehospital rescue, emergency room treatments, and hospital specialist treatments was built under the rule for information sharing and improving severe trauma treatments. Treatment outcomes were compared between before and 1 year after the implementation of the SRP. Results: The outcomes of a total of 74,615 and 12,051 trauma cases were collected from 12 hospitals before and after the implementation of the SRP. Implementation of the SRP led to efficient cooperation and information sharing of different treatment services. The emergency response time, prehospital transit time, emergency rescue time, consultation call time, and mortality rate of patients were 24.24 ± 4.32 min, 45.69 ± 3.89 min, 6.38 ± 1.05 min, 17.53 ± 0.72 min, and 33.82% ± 3.87% (n = 441), respectively, before the implementation of the standardization and significantly reduced to 10.11 ± 3.21 min, 22.39 ± 4.32 min, 3.26 ± 0.89 min, 3.45 ± 0.45 min, and 20.49% ± 3.11%, separately (n = 495, P < 0.05) after that. Conclusions: Staff training and SRP can significantly improve the efficiency of severe trauma treatments in China.