Neuroprotective effects of ultrasound-guided nerve growth factor injections after sciatic nerve injury

Nerve growth factor（NGF） plays an important role in promoting neuroregeneration after peripheral nerve injury. However, its effects are limited by its short half-life; it is therefore important to identify an effective mode of administration. High-frequency ultrasound（HFU） is increasingly used in the clinic for high-resolution visualization of tissues, and has been proposed as a method for identifying and evaluating peripheral nerve damage after injury. In addition, HFU is widely used for guiding needle placement when administering drugs to a specific site. We hypothesized that HFU guiding would optimize the neuroprotective effects of NGF on sciatic nerve injury in the rabbit. We performed behavioral, ultrasound, electrophysiological, histological, and immunohistochemical evaluation of HFU-guided NGF injections administered immediately after injury, or 14 days later, and compared this mode of administration with intramuscular NGF injections. Across all assessments, HFU-guided NGF injections gave consistently better outcomes than intramuscular NGF injections administered immediately or 14 days after injury, with immediate treatment also yielding better structural and functional results than when the treatment was delayed by 14 days. Our findings indicate that NGF should be administered as early as possible after peripheral nerve injury, and highlight the striking neuroprotective effects of HFU-guided NGF injections on peripheral nerve injury compared with intramuscular administration.

The study on the mechanical characteristics of articular cartilage in simulated microgravity

The microgravity environment of a long-term space flight may induce acute changes in an astronaut＇s musculo-skeletal systems. This study explores the effects of simulated microgravity on the mechanical characteristics of articular cartilage. Six rats underwent tail suspension for 14 days and six additional rats were kept under normal earth gravity as controls. Swelling strains were measured using high-frequency ultrasound in all cartilage samples subject to osmotic loading. Site-specific swelling strain data were used in a triphasic theoretical model of cartilage swelling to determine the uniaxial modulus of the cartilage solid matrix. No severe surface irregularities were found in the cartilage samples obtained from the control or tail-suspended groups. For the tail-suspended group, the thickness of the cartilage at a specified site, as determined by ultrasound echo, showed a minor decrease. The uniaxial modulus of articular cartilage at the specified site decreased significantly, from （6.31 ± 3.37） MPa to （5.05 ± 2.98）MPa （p 〈 0.05）. The histology- stained image of a cartilage sample also showed a reduced number of chondrocytes and decreased degree of matrix staining. These results demonstrated that the 14 d simulated microgravity induced significant effects on the mechanical characteristics of articular cartilage. This study is the first attempt to explore the effects of simulated microgravity on the mechanical characteristics of articular cartilage using an osmotic loading method and a triphasic model. The conclusions may provide reference information for manned space flights and a better understanding of the effects of microgravity on the skeletal system.

A novel tissue engineered nerve graft constructed with autologous vein and nerve microtissue repairs a longsegment sciatic nerve defect

Veins are easy to obtain,have low immunogenicity,and induce a relatively weak inflammatory response.Therefore,veins have the potential to be used as conduits for nerve regeneration.However,because of the presence of venous valves and the great elasticity of the venous wall,the vein is not conducive to nerve regeneration.In this study,a novel tissue engineered nerve graft was constructed by combining normal dissected nerve microtissue with an autologous vein graft for repairing 10-mm peripheral nerve defects in rats.Compared with rats given the vein graft alone,rats given the tissue engineered nerve graft had an improved sciatic static index,and a higher amplitude and shorter latency of compound muscle action potentials.Furthermore,rats implanted with the microtissue graft had a higher density and thickness of myelinated nerve fibers and reduced gastrocnemius muscle atrophy compared with rats implanted with the vein alone.However,the tissue engineered nerve graft had a lower ability to repair the defect than autogenous nerve transplantation.In summary,although the tissue engineered nerve graft constructed with autologous vein and nerve microtissue is not as effective as autologous nerve transplantation for repairing long-segment sciatic nerve defects,it may nonetheless have therapeutic potential for the clinical repair of long sciatic nerve defects.This study was approved by the Experimental Animal Ethics Committee of Chinese PLA General Hospital(approval No.2016-x9-07)on September 7,2016.

Influence of mobile education on joint function and quality of life in patients after total hip arthroplasty

Objective：To explore the influence of applying educational animated film as continuous post-discharge rehabilitation guidance for patients after total hip arthroplasty（THA）.Methods：Sixty patients discharged after THA were randomly divided into two groups.Traditional methods,such as distributing manuals of rehabilitation guidance on THA and phone call follow-ups,were adopted in the control group,whereas educational animated film was used as continuous rehabilitation guidance after discharge in the experimental group.Differences in recovery of hip joint function,accuracy of functional exercise,mastery of rehabilitation knowledge and quality of life between the two groups were compared.Results：The experimental group had superior performance on all indicators compared to the control group（P〈0.05）.Conclusions：The use of educational animated film as continuous post-discharge rehabilitation guidance in patients after THA achieved better effects than traditional education methods.

A method of measuring the [α/Fe] ratios from the spectra of the LAMOST survey

The [α/Fe] ratios in stars are good tracers to probe the formation history of stellar populations and the chemical evolution of the Galaxy. The spectroscopic survey of LAMOST provides a good opportunity to determine [α/Fe] of millions of stars in the Galaxy. We present a method of measuring the [α/Fe]ratios from LAMOST spectra using the template-matching technique of the LSP3 pipeline. We use three test samples of stars selected from the ELODIE and MILES libraries, as well as the LEGUE survey to validate our method. Based on the test results, we conclude that our method is valid for measuring [α/Fe]from low-resolution spectra acquired by the LAMOST survey. Within the range of the stellar parameters Teff= [5000, 7500] K, log g = [1.0, 5.0] dex and [Fe/H]= [onsistent with values derived from high-resolution spectra,-1.5, ＋0.5] dex, our [α/Fe] measurements are c and the accuracy of our [α/Fe] measurements from LAMOST spectra is better than 0.1 dex with spectral signal-to-noise higher than 20.

pH-dependent corrosion initiation behavior induced by inclusions of low alloy steel in simulated marine environments

The initial pitting corrosion behavior triggered by inclusions in S420 low alloy steel in acidic artificial seawater(ASW)and weak-alkaline ASW was characterized.The geometric data of the corrosion pits formed in the ASW with different pH were calculated.The pH of the ASW has an obvious influence on the pit shape.The pits in acidic ASW exhibit a funnel shape,while those in weak-alkaline ASW present a cone shape with a larger pit volume.The reason for the difference in the morphology and size of the corrosion pits induced by inclusion is that it is easier to trigger micro-galvanic corrosion in different structures and different areas of the pits in the acidic environment.