Machine learning for differentiation of lipid-poor adrenal adenoma and subclinical pheochromocytoma based on multiphase CT imaging radiomics.

BACKGROUND: There is a paucity of research investigating the application of machine learning techniques for distinguishing between lipid-poor adrenal adenoma (LPA) and subclinical pheochromocytoma (sPHEO) based on radiomic features extracted from non-contrast and dynamic contrast-enhanced computed tomography (CT) scans of the abdomen. METHODS: We conducted a retrospective analysis of multiphase spiral CT scans, including non-contrast, arterial, venous, and delayed phases, as well as thin- and thick-thickness images from 134 patients with surgically and pathologically confirmed. A total of 52 patients with LPA and 44 patients with sPHEO were randomly assigned to training/testing sets in a 7:3 ratio. Additionally, a validation set was comprised of 22 LPA cases and 16 sPHEO cases from two other hospitals. We used 3D Slicer and PyRadiomics to segment tumors and extract radiomic features, respectively. We then applied T-test and least absolute shrinkage and selection operator (LASSO) to select features. Six binary classifiers, including K-nearest neighbor (KNN), logistic regression (LR), decision tree (DT), random forest (RF), support vector machine (SVM), and multi-layer perceptron (MLP), were employed to differentiate LPA from sPHEO. Receiver operating characteristic (ROC) curves and area under the curve (AUC) values were compared using DeLong's method. RESULTS: All six classifiers showed good diagnostic performance for each phase and slice thickness, as well as for the entire CT data, with AUC values ranging from 0.706 to 1. Non-contrast CT densities of LPA were significantly lower than those of sPHEO (P < 0.001). However, using the optimal threshold for non-contrast CT density, sensitivity was only 0.743, specificity 0.744, and AUC 0.828. Delayed phase CT density yielded a sensitivity of 0.971, specificity of 0.641, and AUC of 0.814. In radiomics, AUC values for the testing set using non-contrast CT images were: KNN 0.919, LR 0.979, DT 0.835, RF 0.967, SVM 0.979, and MLP 0.981. In the validation set, AUC values were: KNN 0.891, LR 0.974, DT 0.891, RF 0.964, SVM 0.949, and MLP 0.979. CONCLUSIONS: The machine learning model based on CT radiomics can accurately differentiate LPA from sPHEO, even using non-contrast CT data alone, making contrast-enhanced CT unnecessary for diagnosing LPA and sPHEO.

A special healing pattern in stable metaphyseal fractures.

BACKGROUND AND PURPOSE: Metaphyseal fractures heal in a rapid fashion that is different from the bone shaft healing process. Animal studies have focused on diaphyseal fractures. We investigated the metaphyseal fracture-healing process in rabbits. ANIMALS AND METHODS: 60 rabbits (divided into 12 groups) underwent proximal tibial osteotomy, anatomical reduction, and fixation with screws. After surgery, the proximal tibiae were harvested at different time points for histology. RESULTS: No obvious osteonecrosis or bone resorption were found 2 weeks after surgery. From day 5 to week 5, woven bone or new trabeculae formed. From week 2, remodeling into lamellar bone started and reached a peak at week 6. These 3 stages overlapped. Histomorphometry showed that the structure changed as a unimodal curve. INTERPRETATION: The healing process of metaphyseal fractures appears to differ from the commonly studied healing process in diaphyseal fractures. It is rapid, and can be divided into 4 histological stages: cellular activation and differentiation, formation of woven bone, transformation of woven bone into lamellar bone, and further remodeling.

[Nerve baby-sitter in reverse end-to-side neurorrhaphy preserves the structure of denervated muscle in rats].

OBJECTIVE: To explore the protected effect of sensory baby-sitter in reverse end-to-side fashion on denervated muscle. METHODS: The tibial nerve of twelve female adult Sprague Dawley rats was transected. Six animals served as controls. In the other rats, the end of the sural nerve was connected to the side of the distal tibial nerve stump. After twelve weeks, the wet weight, cross-sectional area, motor endplate perimeter from gastrocnemius muscle were examined. RESULTS: The difference in wet weight between the experimental group and the control group was statistically significant (39.2% ± 6.8% vs. 19.5% ± 4.3%, P<0.05). Histological observation of the unprotected muscles displayed wide areas of atrophied fibers and considerable connective tissue hyperplasia, whereas the structure of the experimental rats was preserved and there was only a slight increase in connective tissue. The average cross-sectional area and motor endplate perimeter of muscle fibers were significantly larger in the experimental group than in the control group [(1 148.85 ± 547.18) µm² vs. (575.05 ± 140.51) µm², (102.84 ± 53.29) µm vs. (59.60 ± 26.71) µm, respectively]. CONCLUSION: Sensory baby-sitter in reverse end-to-side neurorrhaphy preserves the structure of denervated muscle in rats.

[Traffic injuries of pre-hospital treatment in the urban area of Beijing].

OBJECTIVE: To evaluate the current condition of urban road traffic injuries (RTIs) according to Beijing Emergency Medical Center (BEMC) from Jan. 1, 2004 to Dec. 31, 2010, analyze the social characteristics and explore the possible methods for prevention and improvement. METHODS: Using data from the Beijing Emergency Medical Center, we collected 19 550 victims who were involved in RTIs in Beijing from Jan. 1, 2004 to Dec. 31, 2010. The personal information, time of the injury event, road user type and striking vehicle type, as well as the site and severity of injury, were analyzed using Excel 2007 and SPSS 17.0 software with ANOVA of variance and Chi-squared tests. RESULTS: The annual rate of RTIs was 120.0 per 100 000 people in Beijing, and the mortality rate was about 4.97 per 100 000 people. Male victims were more than female victims (11 737 persons vs. 7 618 persons).The mean age was (72.92 ± 5.67) years. Overall, RTIs in all the age groups happened in October commonly, and were inclined to daytime, especially at noon. But different age groups had their special hour distribution features of RTIs. Traffic collisions occurred most frequently in pedestrians and cyclists (7 588,38.81%;3 790,19.39%). Majorities of victims presented with head injuries and lower-limb injuries(8 343,42.68%; 6 828,34.93%). These collisions included car striking accidents (11 490, 58.77%). And most of the older adults were classified as medium in severity (11 718, 59.94%). CONCLUSION: The prevention and treatment of RTIs, should focus on targeted prevention solutions and standardized pre-hospital rescue, according to specific population, time interval and vehicle usage.

[Generation and characterization of peripheral nerve animal model of pure motor/sensory nerve fibers].

OBJECTIVE: To generate peripheral nerve animal model of pure motor nerve fibers/pure sensory nerve fibers, and identify them. METHODS: The SPF SD rats were adopted in this study, and divided into 3 groups. In group A, we ablated L2-L4 ventral roots (VRs) to generate peripheral nerve animal model of pure sensory fibers. In group B, we ablated L2-L4 dorsal root ganglions (DRGs) to generate peripheral nerve animal model of pure motor fibers. Two time end-points were set as 2 weeks and 4 weeks. Neuron cells in lumbar spinal cords were detected by immunohistochemical staining with antibody of neuronal nuclei (NeuN). Motor neuron cells in lumbar spinal cords of pure motor fiber animal models and sensory neuron cells in lumbar spinal cords of pure sensory fiber animal models were counted respectively, and then compared to that of normal animals. Femoral nerves distal to the furcation were stained in osmium tetroxide, and then myelinated nerve fibers in the muscle branch and cutaneous branch of femoral nerve were counted respectively. RESULTS: The mean numbers of sensory neuron cells and motor neuron cells in normal lumbar spinal cords were 62.57 ± 1.02 and 29.73 ± 3.03 per 10 × 20 visual field respectively. For different end-points, the mean numbers of sensory neuron cells after ablating vental foots were 62.12 ± 1.77 (2 weeks), 62.15 ± 1.32 (4 weeks) per 10 × 20 visual field respectively; the mean numbers of motor neuron cells after ablating DRGs were 30.12 ± 0.44 (2 weeks), 30.00 ± 1.87 (4 weeks) per 10 × 20 visual field respectively. In group A, motor axons in muscle branch were degenerated as the sensory axons in muscle branch and cutaneous branch were not changed. The senory axons in femoral nerve for the two end-points were 1 558.17 ± 50.14 (2 weeks) and 1 544.00 ± 47.42 (4 weeks). In group B, sensory axons in muscle branch were degenerated as the motor axons were reserved. The motor axons in muscle branch for the two end-points were 387.67 ± 48.50 (2 weeks) and 393.50 ± 27.86 (4 weeks). There was no statistically significant difference in these mean numbers for the two end-points. The degenerating axons and myelin sheath had not been totally eliminated by the endpoint of 2 weeks. CONCLUSION: Peripheral nerve animal model of pure motor fibers can be generated by ablating L2-L4 DRGs; peripheral nerve animal model of pure sensory fibers can be generated by ablating L2-L4 ventral roots. The degenerating axons and myelin sheath have been totally eliminated by the end-point of 4 weeks. Ablating the ventral roots does not influence the survival of sensory neuron cells; and ablating the DRGs does not influence the survival of motor neuron cells.

Tris(aceto-nitrile-κN)dichlorido(tri-phenyl-phosphane-κP)ruthenium(II) aceto-nitrile monosolvate.

In the title complex, [RuCl2(CH3CN)3(C18H15P)]·CH3CN, the coordination geometry of the Ru(II) atom is distorted octa-hedral, defined by one P atom from a tri-phenyl-phosphane ligand, three N atoms from three aceto-nitrile ligands and two Cl atoms. The three acetronitile ligands linearly bind to the Ru(II) atom, with Ru-N-C angles of 172.6 (2), 179.9 (2) and 171.4 (2)°.

[Establishment and evaluation of animal model for studying the effect of traumatic brain injury on bone fracture healing].

OBJECTIVE: To establish a stable animal model for studying the effect of traumatic brain injury on bone fracture healing. METHODS: Eighty adult male Sprague-Dawley rats were randomly divided into fracture combined brain injury group (A) and simple fracture group (B). Animals of the two groups were killed 6 hours, 1 week, 2 weeks, 1 month and 2 months after trauma, respectively. Their brain histopathology changes were observed and neurological severity scores (NSS, 0 through 25 from no injury to severe injury) determined to measure the brain injury after head trauma, and fracture-healing was assessed by measuring callus volume and X ray examination at the scheduled time points after trauma. The callus volumes were compared between the groups using independent-samples t test 1 week, 2 weeks, 1 month and 2 months after trauma respectively. A value of P<0.05 was considered statistically significant. RESULTS: Ninety percent of the rats of group A presented with hemiplegia and the mortality rate was 10% (4/40) . The survived rats developed decorticated flexion deformity of the forelimbs, with behavioral depression, and lost some reflexes and muscle tone. The NSS were 10.83±1.94, 9.33±0.82, 8.17±1.17, 7.83±0.75 and 8.07±0.82 with 6 hours, 1 week, 2 weeks, 1 month and 2 months after trauma, respectively. It showed that the animals received moderate head injury, which tended to be stable from 2 weeks after trauma. Brain pathology showed that blood brain barrier was destroyed, and neurons were degenerative and necrotic at and around the trauma sites. The callus volumes(unit: mm(3)) of the two groups 1 week, 2 weeks, 1 month and 2 months after trauma were 60.03±28.05 and 32.80±11.04, 78.54±15.16 and 51.36±23.02, 93.01±10.65 and 72.38±20.38, 115.26±40.00 and 60.30±13.34, respectively. The callus volumes of the two groups 2 weeks, 1 month and 2 months after trauma were statistically and significantly different (P values were 0.036, 0.006 and 0.01 respectively), and there was no difference 1 week after trauma (P=0.065). CONCLUSION: This model is capable of producing accurately quantified brain injury. The animal model is credible, stable and reproducible, so it is an effective platform for studying the effect of traumatic brain injury on fracture.

[Clinical effect observation of biodegradable conduit small gap tublization repairing peripheral nerve injury].

OBJECTIVE: To observe the clinical effect of biodegradable conduit small gap tublization to repair peripheral nerve injury. METHODS: In the study, 30 cases of fresh peripheral nerve injury in the upper extremities were recruited. After formally informed and obtaining the consent, the recruited patients were divided into the degradable chitin conduit tublization group (experimental group: 15 cases) and traditional epineurial neurorrhaphy group (control group: 15 cases). Their nerve functional recovery conditions were clinically observed according to the standard score methods provided by SHEN Ning-jiang and British Medical Research Council. The excellent and good rates of the overall nerve functional recovery were calculated. The electrophysiologic study was carried out after 6 months. RESULTS: Of the total 30 cases, 28 were followed up, and there were 14 cases in the degradable chitin conduit tublization group and traditional epineurial neurorrhaphy group. The operation procedure was very simple, and the mean suture time [(8.0±0.8) min] was 20% shorter than that of the traditional epineurial neurorrhaphy group [(10.0±0.6) min]. All the wounds in the degradable chitin conduit tublization group healed as expected without rejection, hypersensitive reaction or anomalous draining. Electrophysiology examination results after 6 months displayed that the sensory nerves conduction velocity recovery rate was 77.37% of the normal value, and motor nerve conduction velocity recovery rate was 70.09% in the degradable chitin conduit tublization group. The sensory nerves conduction velocity recovery rate was 61.69% of the normal value, and motor nerve conduction velocity recovery rate was 56.15% in the traditional epineurial neurorrhaphy group. The exact propability methods was applied in the comparison of sensory and motor nerve conduction velocity recovery rate, and there was no statistically significant of two groups(sensory nerve conduction velocity recovery rate P=0.678;motor nerve conduction velocity recovery rate P=0.695). The combinated functional recovery excellent and good rates after repair in the degradable chitin conduit tublization group were 78.57%, while 28.57% in the traditional epineurial neurorrhaphy group. The Fisher's exact probabilistic method was applied in the comparison of combinated functional recovery excellent and good rates, and there was statistically significant of two groups(P=0.021). CONCLUSION: The operation procedure of the degradable chitin conduit tublization is very simple and the clinical recovery effect is much better than that of the traditional epineurial neurorrhaphy. The biodegradable conduit small gap tublization methods to repair peripheral nerve injury has the possibility to substitute the traditional epineurial neurorrhaphy.

MicroRNA is a potential target for therapies to improve the physiological function of skeletal muscle after trauma.

MicroRNAs can regulate the function of ion channels in many organs. Based on our previous study we propose that miR-142a-39, which is highly expressed in denervated skeletal muscle, might affect cell excitability through similar mechanisms. In this study, we overexpressed or knocked down miR-142a-3p in C2C12 cells using a lentivirus method. After 7 days of differentiation culture, whole-cell currents were recorded. The results showed that overexpression of miR-142a-3p reduced the cell membrane capacitance, increased potassium current density and decreased calcium current density. Knockdown of miR-142a-3p reduced sodium ion channel current density. The results showed that change in miR-142a-3p expression affected the ion channel currents in C2C12 cells, suggesting its possible roles in muscle cell electrophysiology. This study was approved by the Animal Ethics Committee of Peking University in July 2020 (approval No. LA2017128).

The anatomical, electrophysiological and histological observations of muscle contraction units in rabbits: a new perspective on nerve injury and regeneration.

In the conventional view a muscle is composed of intermediate structures before its further division into microscopic muscle fibers. Our experiments in mice have confirmed this intermediate structure is composed of the lamella cluster formed by motor endplates, the innervating nerve branches and the corresponding muscle fibers, which can be viewed as an independent structural and functional unit. In this study, we verified the presence of these muscle construction units in rabbits. The results showed that the muscular branch of the femoral nerve sent out 4-6 nerve branches into the quadriceps and the tibial nerve sent out 4-7 nerve branches into the gastrocnemius. When each nerve branch of the femoral nerve was stimulated from the most lateral to the medial, the contraction of the lateral muscle, intermediate muscle and medial muscle of the quadriceps could be induced by electrically stimulating at least one nerve branch. When stimulating each nerve branch of the tibial nerve from the lateral to the medial, the muscle contraction of the lateral muscle 1, lateral muscle 2, lateral muscle 3 and medial muscle of the gastrocnemius could be induced by electrically stimulating at least one nerve branch. Electrical stimulation of each nerve branch resulted in different electromyographical waves recorded in different muscle subgroups. Hematoxylin-eosin staining showed most of the nerve branches around the neuromuscular junctions consisted of one individual neural tract, a few consisted of two or more neural tracts. The muscles of the lower limb in the rabbit can be subdivided into different muscle subgroups, each innervated by different nerve branches, thereby allowing much more complex muscle activities than traditionally stated. Together, the nerve branches and the innervated muscle subgroups can be viewed as an independent structural and functional unit. This study was approved by the Animal Ethics Committee of Peking University People's Hospital (approval No. 2019PHE027) on October 20, 2019.

Effects of delayed repair of peripheral nerve injury on the spatial distribution of motor endplates in target muscle.

Motor endplates (MEPs) are important sites of information exchange between motor neurons and skeletal muscle, and are distributed in an organized pattern of lamellae in the muscle. Delayed repair of peripheral nerve injury typically results in unsatisfactory functional recovery because of MEP degeneration. In this study, the mouse tibial nerve was transected and repaired with a biodegradable chitin conduit, immediately following or 1 or 3 months after the injury. Fluorescent α-bungarotoxin was injected to label MEPs. Tissue optical clearing combined with light-sheet microscopy revealed that MEPs were distributed in an organized pattern of lamellae in skeletal muscle after delayed repair for 1 and 3 months. However, the total number of MEPs, the number of MEPs per lamellar cluster, and the maturation of single MEPs in gastrocnemius muscle gradually decreased with increasing denervation time. These findings suggest that delayed repair can restore the spatial distribution of MEPs, but it has an adverse effect on the homogeneity of MEPs in the lamellar clusters and the total number of MEPs in the target muscle. The study procedures were approved by the Animal Ethics Committee of the Peking University People's Hospital (approval No. 2019PHC015) on April 8, 2019.

Portion of a nerve trunk can be used as a donor nerve to reconstruct the injured nerve and donor site simultaneously.

This study aims to estimate the effects of using a portion of a nerve trunk to repair itself and the injured nerve simultaneously. Proximal 1/2 median nerve served as donor nerve to repair the distal 1/2 median and whole ulnar nerve. Four months postoperation, the number of myelinated axons and nerve conduction velocities of the distal half median and ulnar nerve were (2033 ± 135 and 24.6 ± 5.3 m/s) and (1138 ± 228 and 30.3 ± 7.2 m/s). It suggests that using a portion of a nearby nerve truck to reconstruct itself and the injured nerve simultaneously is a practical method for severe peripheral nerve injury.

Can "dor to dor+rec neurorrhaphy" by biodegradable chitin conduit be a new method for peripheral nerve injury?

This study aims to estimate the effects of using one donor nerve to repair the injured nerve and itself simultaneously by biodegradable chitin conduit. Proximal median nerve served as donor nerve to repair the distal median and whole ulnar nerve. Four months postoperation, the number of myelinated axons and nerve conduction velocities of the distal median and ulnar nerve were (2085 ± 215 and 24.4 ± 5.9 m/s), and (1193 ± 102 and 30.7 ± 11.2 m/s). Recovery of the tetanic muscle forces of the reinvervated muscles were also observed. It suggests that Dor to Dor+Rec neurorrhaphy is a practical method for severe peripheral nerve injury.

[Small-gap bridging technology for peripheral nerve injury repair and the new sleeve material].

The peripheral nerve injury is a common injury in clinical practice. For centuries, traditional epineurial and perineurial suture techniques have been used to repair nerve transection after peripheral nerve injuries. As there are several types of nerve fibers in neural stump, accurate and effective regeneration of the fibers is limited. The outcome of repairing nerve injury has little improvement till now. Meanwhile , the selective regeneration of peripheral nerve fibers has been gradually confirmed by researchers. The limitation of traditional epineurial and perineurial suture techniques and the phenomenon of selective regeneration of nerve fibers had inspired us with the creative idea: the small-gap bridging suture techniques, which might take the place of the conventional epineurial and perineurial suture methods. We had made a series of detailed studies about this new method, devised a simple and reliable suture method and established an animal model of small-gap bridging suture technique. By observing peripheral nerve regeneration effect of nerve suture with small gap bridging by different gap lengths, we found that the optimal gap was between 1 to 3 mm, developed an artificial conduit with good biocompatibility and gradually applied this new conduit to mammals and primate animal experiments and clinical trials. All the studies obtained reliable results, which confirmed that the small-gap bridging suture was suitable to replace the traditional epineurium suture repairing the peripheral nerve injury. In 2010, this series of research gained the First Prize of Outstanding Scientific Achievement Award by the Ministry of Education.

[Neurofilament immune fluorescence staining: a new method for observing the morphology of the motor endplate].

OBJECTIVE: To investigate the effect of neurofilament (NF) immune fluorescence staining on observing morphology of the motor endplate. METHODS: Six SPF rats were used and their bilateral soleus muscles harvested under anesthesia. Then the samples were fixed with polyphosphate formaldehyde, and made frozen sections. Finally the neurofilament immunofluorescence staining was performed. The morphology of the motor endplate was observed under fluorescence microscope and laser scanning confocal fluorescence microscope. RESULTS: The claw-shape motor endplate was seen clearly under the fluorescent microscope and laser scanning confocal fluorescence microscope, and the images observed used to reconstruct the three-dimensional structure of motor endplate. CONCLUSION: Neurofilament immune fluorescence staining is a useful method for the morphology study of the motor endplate.

Identification of four differentially expressed genes associated with acute and chronic spinal cord injury based on bioinformatics data.

Complex pathological changes occur during the development of spinal cord injury (SCI), and determining the underlying molecular events that occur during SCI is necessary for the development of promising molecular targets and therapeutic strategies. This study was designed to explore differentially expressed genes (DEGs) associated with the acute and chronic stages of SCI using bioinformatics analysis. Gene expression profiles (GSE45006, GSE93249, and GSE45550) were downloaded from the Gene Expression Omnibus database. SCI-associated DEGs from rat samples were identified, and Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed. In addition, a protein-protein interaction network was constructed. Approximately 66 DEGs were identified in GSE45550 between 3-14 days after SCI, whereas 2418 DEGs were identified in GSE45006 1-56 days after SCI. Moreover, 1263, 195, and 75 overlapping DEGs were identified between these two expression profiles, 3, 7/8, and 14 days after SCI, respectively. Additionally, 16 overlapping DEGs were obtained in GSE45006 1-14 days after SCI, including Pank1, Hn1, Tmem150c, Rgd1309676, Lpl, Mdh1, Nnt, Loc100912219, Large1, Baiap2, Slc24a2, Fundc2, Mrps14, Slc16a7, Obfc1, and Alpk3. Importantly, 3882 overlapping DEGs were identified in GSE93249 1-6 months after SCI, including 3316 protein-coding genes and 567 long non-coding RNA genes. A comparative analysis between GSE93249 and GSE45006 resulted in the enrichment of 1135 overlapping DEGs. The significant functions of these 1135 genes were correlated with the response to the immune effector process, the innate immune response, and cytokine production. Moreover, the biological processes and KEGG pathways of the overlapping DEGs were significantly enriched in immune system-related pathways, osteoclast differentiation, the nuclear factor-κB signaling pathway, and the chemokine signaling pathway. Finally, an analysis of the overlapping DEGs associated with both acute and chronic SCI, assessed using the expression profiles GSE93249 and GSE45006, identified four overlapping DEGs: Slc16a7, Alpk3, Lpl and Nnt. These findings may be useful for revealing the biological processes associated with SCI and the development of targeted intervention strategies.

Temporal changes in the spinal cord transcriptome after peripheral nerve injury.

Peripheral nerve injury may trigger changes in mRNA levels in the spinal cord. Finding key mRNAs is important for improving repair after nerve injury. This study aimed to investigate changes in mRNAs in the spinal cord following sciatic nerve injury by transcriptomic analysis. The left sciatic nerve denervation model was established in C57BL/6 mice. The left L4-6 spinal cord segment was obtained at 0, 1, 2, 4 and 8 weeks after severing the sciatic nerve. mRNA expression profiles were generated by RNA sequencing. The sequencing results of spinal cord mRNA at 1, 2, 4, and 8 weeks after severing the sciatic nerve were compared with those at 0 weeks by bioinformatic analysis. We identified 1915 differentially expressed mRNAs in the spinal cord, of which 4, 1909, and 2 were differentially expressed at 1, 4, and 8 weeks after sciatic nerve injury, respectively. Sequencing results indicated that the number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve injury. These mRNAs were associated with the cellular response to lipid, ATP metabolism, energy coupled proton transmembrane transport, nuclear transcription factor complex, vacuolar proton-transporting V-type ATPase complex, inner mitochondrial membrane protein complex, tau protein binding, NADH dehydrogenase activity and hydrogen ion transmembrane transporter activity. Of these mRNAs, Sgk1, Neurturin and Gpnmb took part in cell growth and development. Pathway analysis showed that these mRNAs were mainly involved in aldosterone-regulated sodium reabsorption, oxidative phosphorylation and collecting duct acid secretion. Functional assessment indicated that these mRNAs were associated with inflammation and cell morphology development. Our findings show that the number and type of spinal cord mRNAs involved in changes at different time points after peripheral nerve injury were different. The number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve injury. These results provide reference data for finding new targets for the treatment of peripheral nerve injury, and for further gene therapy studies of peripheral nerve injury and repair. The study procedures were approved by the Ethics Committee of the Peking University People's Hospital (approval No. 2017PHC004) on March 5, 2017.

Intraoperative single administration of neutrophil peptide 1 accelerates the early functional recovery of peripheral nerves after crush injury.

Neutrophil peptide 1 belongs to a family of peptides involved in innate immunity. Continuous intramuscular injection of neutrophil peptide 1 can promote the regeneration of peripheral nerves, but clinical application in this manner is not convenient. To this end, the effects of a single intraoperative administration of neutrophil peptide 1 on peripheral nerve regeneration were experimentally observed. A rat model of sciatic nerve crush injury was established using the clamp method. After model establishment, a normal saline group and a neutrophil peptide 1 group were injected with a single dose of normal saline or 10 µg/mL neutrophil peptide 1, respectively. A sham group, without sciatic nerve crush was also prepared as a control. Sciatic nerve function tests, neuroelectrophysiological tests, and hematoxylin-eosin staining showed that the nerve conduction velocity, sciatic functional index, and tibialis anterior muscle fiber cross-sectional area were better in the neutrophil peptide 1 group than in the normal saline group at 4 weeks after surgery. At 4 and 8 weeks after surgery, there were no differences in the wet weight of the tibialis anterior muscle between the neutrophil peptide 1 and saline groups. Histological staining of the sciatic nerve showed no significant differences in the number of myelinated nerve fibers or the axon cross-sectional area between the neutrophil peptide 1 and normal saline groups. The above data confirmed that a single dose of neutrophil peptide 1 during surgery can promote the recovery of neurological function 4 weeks after sciatic nerve injury. All the experiments were approved by the Medical Ethics Committee of Peking University People's Hospital, China (approval No. 2015-50) on December 9, 2015.

[Amplification effects in nerve regeneration after different segment injury: experiment with rabbit median nerve].

OBJECTIVE: To investigate the impact of different section injury on the median nerve during peripheral nerve regeneration. METHODS: 18 New-Zealand rabbits were divided into 3 groups. We took the proximal, intermediate and distal nerve segment as donor nerve, the restore ratio of the number of donator fibers to recipient fibers is 1:4. We took the corresponding right side nerve as control, the restore ratio of the number of donator fibers to recipient fibers is 1:1. We then observed the general condition of regenerated nerve, counted the number of regenerated fibers, measured its conduction of velocity and wet weights of musculus flexor digitorum sublimis 3 months after operation. RESULTS: The numbers of recipient fiber of 3 different groups were as follows: group I: 1747 +/- 375, group I: 1785 +/- 442, group III: 1863 +/- 321; Control goup I: 2234 +/- 364, control group II: 2319 +/- 237, control group III: 2346 +/- 308. The results of conduction of velocity were: group I: 19.5 m/s, group II: 19.9 m/s, group III: 21.3 m/s; Control group I: 57.1 +/- 3.7 m/s, control group I: 56.4 +/- 2.5 m/s, control group III: 56.8 +/- 2.3 m/s. The results of wet weights of musculus flexor digitorum sublines were as follows: group I: 1.7247 +/- 0.0891 g, group II:1.7239 +/- 0.0903 g, group III: 1.7253 +/- 0.0798 g. Control group I: 2.0448 +/- 0.1013 g, control group II: 2.0433 +/- 0.0861 g, control group III: 2.0456 +/- 0.0947 g. CONCLUSION: The amplification phenomenon exist in every group, the amplified ratio augment according to the distance of the site from neuron, but the conduction of velocity is decreased gradually . The wet weights of musculus flexor digitorum sublines has no significant difference between 3 groups.

Repair of long segmental ulnar nerve defects in rats by several different kinds of nerve transposition.

Multiple regeneration of axonal buds has been shown to exist during the repair of peripheral nerve injury, which confirms a certain repair potential of the injured peripheral nerve. Therefore, a systematic nerve transposition repair technique has been proposed to treat severe peripheral nerve injury. During nerve transposition repair, the regenerated nerve fibers of motor neurons in the anterior horn of the spinal cord can effectively grow into the repaired distal nerve and target muscle tissues, which is conducive to the recovery of motor function. The aim of this study was to explore regeneration and nerve functional recovery after repairing a long-segment peripheral nerve defect by transposition of different donor nerves. A long-segment (2 mm) ulnar nerve defect in Sprague-Dawley rats was repaired by transposition of the musculocutaneous nerve, medial pectoral nerve, muscular branches of the radial nerve and anterior interosseous nerve (pronator quadratus muscle branch). In situ repair of the ulnar nerve was considered as a control. Three months later, wrist flexion function, nerve regeneration and innervation muscle recovery in rats were assessed using neuroelectrophysiological testing, osmic acid staining and hematoxylin-eosin staining, respectively. Our findings indicate that repair of a long-segment ulnar nerve defect with different donor nerve transpositions can reinnervate axonal function of motor neurons in the anterior horn of spinal cord and restore the function of affected limbs to a certain extent.