Tissue engineering for the repair of peripheral nerve injury

Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.

Long-term survival trends of gastric cancer patients between 1972 and 2011 in Qidong

Background:There have been few reports on long-term survival of gastric cancer patients.This study analyzed the survival data of gastric cancer patients obtained from the population-based Qidong Cancer Registry between 1972 and 2011,providing a basis for evaluation of gastric cancer treatment and prognosis.Methods:The cumulative observed survival rate and relative survival rate of gastric cancer patients were calculated using Hakulinen's method via the SURV3.01 software,which was developed by the Finnish Cancer Registry.The date of the last follow-up for the survival status of the 15,401 registered cases was April 30,2012.Results:The 1-,5-,10-,20-,and 30-year observed survival rates were 33.82%,14.18%,10.35%,6.63%,and 4.19%,respectively,and the 1-,5-,10-,20-,and 30-year relative survival rates were 35.43%,18.13%,17.50%,21.96%,and32.84%,respectively.For males,the corresponding observed survival rates were 34.50%,14.40%,10.42%,6.46%,and4.05%,and the corresponding relative survival rates were 36.23%,18.67%,18.28%,23.73%,and 38.61%.For females,the corresponding observed survival rates were 32.62%,13.80%,10.22%,6.95%,and 4.46%,and the corresponding relative survival rates were 34.03%,17.21%,16.28%,19.70%,and 26.78%.Significant differences in relative survival rates were observed between sexes(P=0.003).For the 15-34,35-44,45-54,55-64,65-74,and 75+ age groups,the 5-year relative survival rates were 16.13%,21.77%,18.63%,12.61%,7.99%,and 2.94%,respectively,and the 10-year relative survival rates were 16.49%,22.83%,20.50%,15.97%,15.88%,and 15.73%,respectively.Remarkable improvement could be observed for the 5-,10-,and 15-year relative survival rates in Qidong beginning in the 1980 s.Conclusion:The survival outcome of registered gastric cancer cases in Qidong showed gradual progress over the past two decades.

Microglia:A Central Player in Depression

Microglia are the major immune cells in the central nervous system and play a key role in the normal function of the brain.Microglia exhibit functional diversity,and they control the inflammation in central nervous system through releasing inflammatory cytokine,clearing apoptotic cells via phagocytosis,regulating synaptic plasticity and the formation of neural network by synapse pruning.Recent studies have strongly indicated that the microglial dysfunction is associated with a variety of neuropsychiatric diseases such as depression,which have been termed as“microgliopathy”.The emergency of advanced technologies and tools has enabled us to comprehensively understand the role of microglia in physiology and pathology,and growing studies have targetted microglia to explore the treatment of neuropsychiatric diseases.Here,we describe the key progress of microglia research,and review the recent developments in the understanding of the role of microglia in physiology and etiology of depression.

Diversity patterns of cushion plants on the Qinghai-Tibet Plateau:A basic study for future conservation efforts on alpine ecosystems

The Qinghai-Tibet Plateau(QTP)is an important cushion plant hotspot.However,the distribution of cushion plants on the QTP is unknown,as are the factors that drive cushion plant distribution,limiting our understanding of the evolution of cushion species in the region.In this study,we assessed spatial patterns of total cushion plant diversity(including taxonomic and phylogenetic)over the entire QTP and compared patterns of diversity of cushion plants with different typologies(i.e.,compact vs.loose).We also examined how these patterns were related to climatic features.Our results indicate that the southern QTP hosts the highest total cushion plant richness,especially in the south-central Hengduan Mountains subregion.The total number of cushion species declines from south to north and from southeast to northwest.Compact cushion plants exhibit similar patterns as the total cushion plant richness,whereas loose cushion plants show random distribution.Cushion plant phylogenetic diversity showed a similar pattern as that of the total cushion plant richness.In addition,cushion plant phylogenetic community structure was clustered in the eastern and southwestern QTP,whereas random or overdispersed in other areas.Climatic features represented by annual energy and water trends,seasonality and extreme environmental factors,had significant effects on cushion plant diversity patterns but limited effects on the phylogenetic community structure,suggesting that climatic features indeed promote the formation of cushion plants.Because cushion plants play vital roles in alpine ecosystems,our findings not only promote our understanding of the evolution and formation of alpine cushion plant diversity but also provide an indispensable foundation for future studies on cushion plant functions and thus alpine ecosystem sustainability in the entire QTP region.

Identification and Function of Acid-sensing Ion Channels in RAW 264.7 Macrophage Cells

Activation of acid-sensing ion channels （ASICs） plays an important role in neuroinflammation. Macrophage recruitment to the sites of inflammation is an essential step in host defense. ASIC1 and ASIC3 have been reported to mediate the endocytosis and maturation of bone marrow derived macrophages. However, the expression and inflammation-related functions of ASICs in RAW 264.7 cells, another common macrophage, are still elusive. In the present study, we first demonstrated the presence of ASIC 1, ASIC2a and ASIC3 in RAW 264.7 macrophage cell line by using reverse transcriptase polymerase chain reaction （RT-PCR）, Western blotting and immunofluorescence experiments. The non-specific ASICs inhibitor amiloride and specific homomeric ASICla blocker PcTxl reduced the production of iNOS and COX-2 by LPS-induced activating RAW 264.7 cells. Furthermore, not only amiloride but also PcTxl inhibited the migration and LPS-induced apoptosis of RAW 264.7 cells. Taken together, our findings suggest that ASICs promote the inflammatory response and apoptosis of RAW 264.7 cells, and ASICs may serve as a potential novel target for immunological disease therapy.

Dimethyl sulfide,a metabolite of the marine microorganism,protects SH-SY5Y cells against 6-hydroxydopamine and MPP~＋-induced apoptosis

Dimethyl sulfide(DMS)has been historically recognized as a metabolite of the marine microorganism or a disgusting component for the smell of halitosis patients.In our recent study,DMS has been identified as a cytoprotectant that protects against oxidative-stress induced cell death and aging.We found that at near-physiological concentrations,DMS reduced reactive oxygen species(ROS)in cultured PC12 cells and alleviated oxidative stress.The radical-scavenging capacity of DMS at near-physiological concentration was equivalent to endogenous methionine(Met)-centered antioxidant defense.Methionine sulfoxidereductase A(MsrA),the key antioxidant enzyme in Met-centered defense,bound to DMS and promoted its antioxidant capacity via facilitating the reaction of DMS with ROS through a sulfonium intermediate at residues Cys72,Tyr103,Glu115,followed by the release of dimethyl sulfoxide(DMSO).MTT assay and trypan blue test indicated that supplement of DMS exhibited cytoprotection against 6-hydroxydopamine and MPP+induced cell apoptosis.Furthermore,Msr A knockdown abolished the cytoprotective effect of DMS at near-physiological concentrations.The present study reveals new insight into the potential therapeutic value of DMS in Parkinson disease.

Allelopathic potentials of surrounding vegetation on seedling establishment of alpine cushion Arenaria polytrichoides

When facilitating other species and sustaining plant community structures and biodiversity,alpine cushion plants simultaneously experience negative feedback effects from surrounding vegetation.However,the impact of surrounding vegetation on cushion dynamics remains poorly understood,particularly in terms of allelopathic potentials.To investigate the allelopathic potentials of surrounding vegetation on seedling establishment of the typical cushion plant Arenaria polytrichoides Edgew.along an elevational gradient,we extracted potential allelopathic compounds and tested their impacts on seed germination and seedling growth of A.polytrichoides.In addition,exclusion experiments using activated carbon were conducted to further elucidate these effects.Our results demonstrate that surrounding vegetation exhibits certain allelopathic potentials on A.polytrichoides seedling establishment,with variations observed based on elevation,source and concentration of allelopathy compounds,as well as growing season.Specifcally,low-elevation vegetation exerts pronounced suppression on seedling establishment.Conversely,higher-elevation vegetation generally shows no effect on seed germination but stimulates seedling growth through allelopathy mechanisms.Moreover,aboveground vegetation predominantly inhibits both seed germination and seedling growth in low-elevation communities;however,the effects of belowground vegetation depend on elevation and extract concentration levels.The identifed allelopathic potentials of surrounding vegetation signifcantly infuence the population dynamics of cushion A.polytrichoides by potentially accelerating population degeneration in lower-elevation communities while ensuring consistent population recruitment and expansion in higher-elevation communities.

Woolly and overlapping leaves dampen temperature fluctuations in reproductive organ of an alpine Himalayan forb

Aims studying the ecological significance of highly specialized morpho-logical traits evolved by alpine plants could help us to understand the adaptation and evolution of these plants under severe alpine environ-ment.We explored the adaptive significance of woolly and overlap-ping leaves for reproduction in Eriophyton wallichii,a perennial herb native to the subnival belt of the Himalaya-Hengduan mountains.Methods We examined whether the trichomes could influence the leaf wet-tability,temperature and leaf reflectance spectra in the lab.and we investigated the thermal benefits of the woolly and overlapping leaves for flowers and fruits in the field.Pollen viability and seed germination were also examined in the lab to assess whether these leaves enhance reproductive fitness.Important Findingsour results showed that dense trichomes impart good water repel-lency,absorption of solar radiation and accumulation of leaf heat.The woolly and overlapping leaves increased the interior tempera-ture of flowers and fruits to an optimal level on sunny hours,but prevented them from overheating when transient intense solar radi-ation occurs.This kept optimal temperatures in plants’reproduc-tive organs,thus promoting the development of pollen and seed in alpine environment.

Liver cancer screening in China: practices and its extended questions

Screening for liver cancer(hepatocellular carcinoma)in China started in early 1970s with the application of alpha-fetoprotein(AFP)in high-incidence regions.It has been extended to nationwide areas,emerging from the concepts of conducting screening in populations at-risk with positive hepatitis B surface antigen to the practice programs in rural and urban areas,and finally to the development of recommendations to guide medical practice for health care providers.The implementation of screening for liver cancer has resulted in earlier detection and hence the early curable treatment for patients who have gained short-or long-term survival,and even reduction in mortality rates,although these outcomes are more anecdotal than rigorously evidence-based.AFP or ultrasound examination has been considered as sensitive and specific methods for early detection but are with limitations.The combined use of these two modalities for screening populations at-risk every six months seems to have been reached consensus.The feasibility of screening for liver cancer is still debated because of differing opinions and even opposition to the choice of targeted sub-populations,the intrinsic necessity,and the contributions of the main risk factors among Western countries and China/Asian areas.Yet,the over 51%of global burden of liver cancer is in China,the solution to the early detection and treatment of liver cancer should fully consider the actual situation in China.The effectiveness of screening for liver cancer is worthy of anticipation.

Effects of Isothermal Aging on Microstructure and Mechanical Property of Low-Carbon RAFM Steel

In order to investigate the microstructure and mechanical property evolution of low-carbon reduced activation ferritic/martensitic(RAFM)steel during isothermal aging,the normalized and tempered specimens were aged at 600℃for 500,1000,and 3000 h,respectively.The microstructural evolution with aging time was analyzed,including the precipitation and growth of M23C6 and MX-type carbides as well as the formation of Laves phase.The results indicate that the coarsening of M23C6 is more obvious than that of MX with increase in aging time.During the long-term thermal exposure,the Fe2 W Laves phase precipitates adjacent to M23C6 along the prior austenite grain boundaries and packet boundaries.Lower carbon content can delay the precipitation of Laves phase compared to the steel containing higher carbon.In addition,the Laves phase precipitated along boundaries can provide the precipitation strengthening,slightly increasing the tensile strength of low-carbon RAFM steel after aging for 3000 h.

Effects of tantalum on austenitic transformation kinetics of RAFM steel

The RAFM（reduced activation ferritic/martensitic）steels containing different tantalum contents（0wt.%,0.027wt.%,0.073wt.%）were designed and cast.Differential scanning calorimetry and optical microscopy were employed to explore the influence of tantalum content on the austenitic transformation of RAFM steels.The austenitic transformation kinetics was described by aphase-transformation model.The model,involving site saturation nucleation,diffusion-controlled growth and impingement correction,was established based on the classical Johnson-Mehl-Avrami-Kolmogorov model.The phase-transformation kinetics parameters,including D_0（pre-exponential factor for diffusion）and Q_d（activation energy for diffusion）,were calculated by fitting the experimental data and the kinetic model.The results indicated that the average grain size is decreased with the increase of tantalum.The values of A_（c1） and A_（c3） （onset and finish temperature of austenitic transformation,respectively）are increased by increasing the tantalum content.The increase of tantalum caused the decrease of D_0.However,Q_d is increased with the increase of tantalum.In addition,as a carbides forming element,tantalum would reduce the carbon diffusion coefficient and slow down the austenitic transformation rate.