Role of sphingosine 1-phosphate receptor type 1 in lymphocyte egress from secondary lymphoid tissues and thymus

Circulation of mature lymphocytes between blood and secondary lymphoid tissues plays a central role in the immune system. Homing of lymphocytes from blood into secondary lymphoid tissues beyond high endothelial venules is highly dependent on the interaction between the chemokines CCL19, CCL21, CXCL12, and CXCL13, and their receptors CCR7, CXCR4 and CXCR5. However, the molecular mechanism（s） of lymphocyte egress from secondary lymphoid tissues to lymph remained unclear. We have found a new class of immunomodulator, FTY720 by chemical modification of vegetative wasp-derived natural product, ISP-I （myriocin）. FTY720 has been shown to be highly effective in experimental allograft and autoimmune disease models. A striking feature of FTY720 is the induction of a marked decrease in peripheral blood lymphocytes at doses that show immunomodulating activity in these models. The reduction of circulating lymphocytes by FTY720 is caused by sequestration of lymphocytes into secondary lymphoid tissues and thymus. FTY720 is rapidly converted to （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] by sphingosine kinase 2 in vivo. （S）-FTY720-P acting as a potent agonist of S1P receptor type 1 （S1P1）, induces long-term down-regulation of S1P1 on lymphocytes, and thereby inhibits the migration of lymphocytes toward S1P. Thus, it is presumed that FTY720-induced lymphocyte sequestration is due to the inhibition of S1P/S1P1-dependent lymphocyte egress from secondary lymphoid tissues and thymus by its active metabolite （S）-FTY720-P. Throughout the analysis of the mechanism of action of FTY720, it is clarified that S1P/S1P1 interaction plays an important role for lymphocyte egress from secondary lymphoid tissues and thymus.     

Heart＇omicsin＇AGEing （HOMAGE）：design,research objectives and characteristics of the common database

Heart failure is common in older people and its prevalence is increasing.The Heart ＇omics＇ in AGEing（HOMAGE） project aims to provide a biomarker approach that will improve the early diagnosis of heart failure.A large clinical database,based on（1） prospective population studies or（2） cross-sectional,prospective studies or randomized controlled trials（RCTs） of patients at risk for or with overt cardiovascular disease will be constructed to determine most promising ＇omics＇-based biomarkers to identify the risk of developing heart failure and/or comorbidities.Population studies,patient cohorts and RCTs are eligible for inclusion in the common database,if they received ethical approval to obtain and share data and have baseline information on cardiovascular risk factors.Currently,the HOMAGE database includes 43,065 subjects,from 20 studies in eight European countries,including healthy subjects from three population studies in France,Belgium and Italy（n = 7,124）,patients with heart failure（n = 4,312） from four cohorts in the UK,Spain and Switzerland and patients at high risk for cardiovascular disease（n = 31,629） in 13 cohorts.It is anticipated that more partners will join the consortium and enlarge the pooled data.This large merged database will be a useful resource with which to identify candidate biomarkers that play a role in the mechanism underlying the onset and progression of heart failure.     

FTY720, sphingosine 1-phosphate receptor modulator, ameliorates experimental autoimmune encephalomyelitis by inhibition of T cell infiltration

FTY720, a sphingosine 1-phosphate receptor modulator, induces a marked decrease in the number of peripheral blood lymphocytes and exerts immunomodulating activity in various experimental allograft and autoimmune disease models. In this study, we evaluated the effect of FTY720 and its active metabolite, （S）-enantiomer of FTY720-phosphate [（S）-FTY720-P] on experimental autoimmune encephalomyelitis （EAE） in rats and mice. Prophylactic administration of FTY720 at 0.1 to 1 mg/kg almost completely prevented the development of EAE, and therapeutic treatment with FTY720 significantly inhibited the progression of EAE and EAE-associated histological change in the spinal cords of LEW rats induced by immunization with myelin basic protein. Consistent with rat EAE, the development of proteolipid protein-induced EAE in SJL/J mice was almost completely prevented and infiltration of CD4^＋ T cells into spinal cord was decreased by prophylactic treatment with FTY720 and （S）-FTY720-P. When FTY720 or （S）-FTY720-P was given after establishment of EAE in SJL/J mice, the relapse of EAE was markedly inhibited as compared with interferon-β, and the area of demyelination and the infiltration of CD4^＋ T cells were decreased in spinal cords of EAE mice. Similar therapeutic effect by FTY720 was obtained in myelin oligodendrocyte glycoprotein-induced EAE in C57BL/6 mice. These results indicate that FTY720 exhibits not only a prophylactic but also a therapeutic effect on EAE in rats and mice, and that the effect of FTY720 on EAE appears to be due to a reduction of the infiltration of myelin antigen-specific CD4^＋ T cells into the inflammation site. Cellular ＆ Molecular Immunology. 2005;2（6）：439-448.     

Nigerian Population Research on Environment,Gene and Health （NIPREGH）-objectives and protocol

Sub-Saharan Africa is currently undergoing an epidemiological transition from a disease burden largely attributable to communicable diseases to that resulting from a combination of both communicable and chronic non-communicable diseases.Data on chronic disease incidence,lifestyle,environmental and genetic risk factors are sparse in this region.This report aimed at providing relevant information in respect to risk factors that increase blood pressure and lead to development of intermediate cardiovascular phenotypes.We presented the rationale,objectives and key methodological features of the Nigerian Population Research on Environment,Gene and Health（NIPREGH） study.The challenges encountered in carrying out population study in this part of the world and the approaches at surmounting them were also presented.The preliminary data as at 20 November 2013 showed that out of the 205 individuals invited starting from early April 2013,160（72 women） consented and were enrolled;giving a response rate of 78%.Participants＇ age ranged from 18 to 80 years,with a mean（SD） of 39.8（12.4） years and they were of 34 different ethnic groups spread over 24 states out of the 36 states that constitute Nigeria.The mean（SD） of office and home blood pressures were 113.0（15.2） mm Hg systolic,73.5（12.5） mm Hg diastolic and 117.3（15.0） mm Hg systolic,and 76.0（9.6） mm Hg diastolic,respectively.Forty-three（26.8%） participants were hypertensive and 8（5.0%） were diabetic.In addition to having the unique potential of recruiting a cohort that is a true representative of the entire Nigerian population,NIPREGH is feasible and the objectives realisable.     

Quality control and evaluation of human immunodeficiency virus antibody assays used for screening donated blood in China

During 2004, a total of 124 batches of HIV antibody ELISAs from domestic and overseas manufacturers, comprising approximately 60 million tests, were tested for quality and released for screening blood in China. The inter- and intra-batch variation, specificity, and sensitivity were evaluated using a laboratory panel and clinical samples. The inter-batch variation was less than 15% and only 2 of 12 assays had intra-batch variation of less than 20% for 4 dilutions of a control specimen. 257 samples confirmed positive for HIV antibody and 4826 negative samples from different regions in China were used to evaluate the sensitivity and specificity of the assays. The results showed that the sensitivity is in the range from 93.7% to 100% for assays sampled directly from the manufacturers, and 91. 4%-99. 6% for those retrieved from the consumers; the specificity was in the range from 97.88% to 99.97% . The testing environment may vary in different regions of China. Therefore, manufacturers should provide robust assays to satisfy the requirements of these diverse environments, and especially reduce the intra-assay variation and improve the stability of the kits.     

Production and secretion of biologically active human epidermal growth factor in Yarrowia lipolytica

The gene encoding human epidermal growth factor (hEGF) was expressed as a fusion protein with the leader peptide and pro I region of alkaline extracellular protease in the yeast Yarrowia lipolytica. hEGF was purified from culture supernatant by reverse-phase chromatography and analysed by Western-blot hybridisations. The biologically active hEGF in the purified sample was assayed using the radioreceptor assay and estimated to be 100 μg/l. However, the level of expression was found to be substantially low compared to the levels of homologous protein, alkaline extracellular protease (AEP), possibly due to degradation by secreted acid protease(s). A novel and sensitive bioassay was developed to determine the biological activity of hEGF produced at low levels and is based on the effect produced by hEGF in the regenerating tails of the wall lizard. Intramuscular injections of culture supernatant from the recombinant yeast and the standard hEGF led to a drastic reduction in tail regeneration confirming the biological activity of the recombinant hEGF. Received: 15 August / 19 September 1997     

Influence of ozone on the rheological and electrical properties of stored human blood

Blood stored in a blood bank undergoes a series of chemical changes and storage lesions.The purpose of this study was to assess the effect of ozone on the rheological and electrical properties of stored human blood.Venous blood samples,obtained from three healthy humans,were treated with different concentrations of ozone(30,50,70 and 80 μg/mL) for three weeks in vitro.Ozone was generated from portable medical-grade oxygen using electrical corona arc discharge.The ultraviolet-visible absorption of hemoglobin in the wavelength of 300-700 nm showed that ozone in this range did not interact with iron ions and it was not toxic below the concentration of 80 μg/mL.The changes of blood viscosity were also measured.The electrical conductivity and permittivity,in the frequency range from 5 to 50 MHz,were measured in the control and treated samples subjected to different concentrations of ozone at different stored periods.The results showed that the conductivity and permittivity measurements may serve as a useful indicator in the quality assessment of blood samples stored in the blood bank.     

Research on the Construction of Tissue Engineering Scaffolds by Alginate-hyaluronic Acid with Different Characteristics

This research uses alginate and hyaluronic acid as the main component to prepare support, then explores the possibilities as a tissue engineering scaffold. Firstly, prepare HA with various average molecular weight and alginate with different viscosity, mix them up at a certain proportion and make it into a AlgCa2 ＋-HA composite scaffold with a film-forming method. This article discusses the feasibility of this scaffold used in tissue engineering field according to the consequence of moisture content testing, mechanical analysis, and scanning electron microscopy analysis. The structure and properties of AlgCa2 ＋-HA composite scaffold are closely related to some factors such as average molecular weight of hyaluronic acid, hyaluronic acid concentration, alginate viscosity, cross-linking agents and processing technology. The AlgCa2＋-HA composite material, which is at different proportions and adding different cross-linking agent,has some certain characteristics： moisture content ranging from 50% to 95%, tensile strength between 2.69 N/mm2 and 4.299 N/mm2, and elongation at break is about 58% to 160%. The prepared AlgCa2＋-HA composite scaffolds can be used as tissue engineering scaffolds resulting from its high moisture content, good mechanical properties and ideal pore structure.     

Study on Different Modification Methods of Collagen for Tissue Engineering

Because of the excellent biocompatibility and its specific amino sequences, collagen is an ideal biomedical material for tissue engineering applications. But collagen is usually lack of mechanical strength to form a rigid 3-D matrix and lack of ability to resist collagenase. In order to be a tissue engineering scaffold, collagen must strengthen its structures by modifying with chemical crosslinkers. Chemical crosslinkers used for modif- ying collagen fibers include glutaraldehyde （GA）, epoxy compounds （PC） and carbodiim- ides （EDC）. The aim of this study is to choose the best chemical crosslinker from the three reagents. In terms of the resistance to collagenase degradation, chemical cross-link- ing with PC provided the best protection; in terms of the mechanical characterization, chemical cross-linking with GA provided the best;and in terms of the biocompatibility, chemical cross-linking with EDC provided the best. There is not a reagent which has all merits for collagen crosslinking, so we should select the crosslinking reagent as the demands of use ask.     

Expression,Purification and Characterization of C-FADD

FADD is an important proapoptotic adaptor in death receptor-induced apoptosis. Recently, FADD has been found to participate in a variety of non-apoptotic processes, such as development, cell cycle progression and survival. Its non-apoptotic activities were regulated by the phosphorylated status of the serine residue located at the C-terminal region, a domain distinct from the proapoptotic function related DED and DD domains. However, due to the difficulties in expression and crystallization of natural FADD, by far the molecuiar structures of all FADD variants did not contain the C-terminal region. To elucidate the structure-function relationship of C-terminal region, we need to obtain a FADD variant that containing C-terminal region. In this study, mouse FADD （80-205） containing DD domain and C-terminal region, designated as C-FADD, was expressed in E. coli with His-tag at the N-terminus and purified by Ni^2＋ affinity chromatography. The purified protein existed as a homogenous monomer in glutaraldehyde cross-linking analysis and exhibited a typical a-helix spectrum in CD （circular dichroism） assay. In vitro His-tag pull-down assay demonstrated that the purified C-FADD possessed the CK Ia-binding activity which was important for its non-apoptotic function.     

Biocompatibility of fully biodegradable polylactic acid and its copolymers: Present and future applications北大核心

BACKGROUND: Polylactic acid and its copolymers have been widely used in biomedical fields because of their good biocompatibility and biodegradability, which have become a hotspot in the research of biomaterials. OBJECTIVE: To review the biocompatibility of fully degradable polylactic acid and its copolymers. METHODS: A computer-based online retrieval of PubMed and CNKI was performed to search relevant papers published from 2006 to 2016, with the key words of " polylactide, polylactic acid, copolymer, biodegradability, biocompatibility, animal” in English and Chinese, respectively. RESULTS AND CONCLUSION: Polylactic acid and its copolymers as polyester compounds are approved by the US Food and Drug Administration for use in the biomedical field because of their good biocompatibility mainly as drug delivery carriers and temporary implants. Moreover, their side effects in clinical application have attracted attentions. Polylactide copolymers can cause some adverse reactions when used in drug delivery systems, orthopedic and skin care, and other clinical medical fields. These copolymers are deemed to have no impact on the central nervous system, eyes, cardiovessels and other tissues and organs. They also have no virtually genotoxic and carcinogenic effects. Currently, the polylactide copolymer implant mainly results in local reactions in the surrounding tissues, and no systemic reactions have been found. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Expression of IL-10 and TNF-α in Rats with Cerebral Infarction after Transplantation with Mesenchymal Stem Cells

We investigated the effects of bone marrow-derived mesenchymal stem cells （MSCs） transplantation on the recovery of neurological functions in rat＇s MCAO （middle cerebral artery occlusion） model and its mechanism. MSCs were isolated from bone marrow of male Sprague Dawley （SD） rats. Female adult SD rats were randomly assigned into 4 groups： sham-operated group, MCAO group, vehicle group and MCAO ＋ MSCs-treated group. MSCs were injected into the lateral ventricle of rats in the MSCs-treated group and the same volume of PBS was given to the vehicle group. The expressions of IL-10 and TNF-α were assayed by RT-PCR and ELISA detections at day 1 and 4 after MCAO. The infarction volume was measured by TTC-staining. All rats underwent behavioral tests before, as well as 1, 4, and 14 days after MCAO. MSCs significantly improved functional recovery compared with the control at day 14 after transplantation. Compared with the MCAO group and the vehicle group, the expression of IL-10 mRNA and its protein level in the MSCs group significantly upregulated. However, the expression of TNF-α at day 4 after MCAO in the MSCs group significantly decreased compared with that of the MCAO group and the vehicle group. As a result, transplantation with MSCs significantly decreased infarct volume at day 1 and 4. This study strongly suggested transplantation with MSCs could reduce neuronal injury post focal cerebral ischemia in rats partly by regulating the expressions of IL-10 and TNF-α in the brain.     

Investigation of NAD（P） H Fluorescence Decay in Living Cardiomyocytes with Spectrally-resolved Fluorescence Lifetime Spectroscopy

Objective：To study the mitochondrial redox state in experimental animals to sensitively detect early signs of mitochondrial function in pathophysiologieal conditions, such as isehemia. Methods： Fluorescence of nieotinamide adenine dinucleotide （phosphate） , or NAD（P）H, the principal electron donor in mitochondrial respiration responsible for vital ATP supply of cardiomyocytes, is studied for non-invasive fluorescent probing of the mitochondrial function. Examination of NAD （P）H fluorescence in living cardiomyocytes following excitation by UV-pulsed laser diode and detection by spectrally-resolved time-correlated single photon counting （TCSPC） , is based on the simultaneous measurement of the fluorescence spectra and lifetime. Results ： The dynamic characteristics of NAD （P） H fluorescence decay in living rat cardiomyocytes show that at least a 3-exponential decay model, with 0.4 - 0.7 ns, 1.2 - 1.9 ns and 8.0 - 13.0 ns lifetimes, is necessary to describe cardiomyocyte autofluorescenee （AF）. Decay-associated spectra （DSA） revealed the presence of 4 spectrally-distinct populations of NADH molecules in eardiomyocytes with spectral maximum at 470 nm for short-lifetime pool for the first time, and emission peaks at 450 nm, 470 nm and 490 nm for intermediate and long-lifetime pools. Increased mitochondrial NADH content ratio by ketone bodies enhanced the AF intensity, without the significant change in fluorescent lifetimes. Rotenone, the inhibitor of Complex I of the mitochondrial respiratory chain, increased AF and shortened the average fluorescence lifetime. Dinitrophenol （DNP）, an uncoupling agent of the mitochondrial oxidative phosphorylation, lowered AF,broadened the spectral shoulder at 520 nm and increased the average lifetime. These effects, comparable to the changes in the concentration and in the rate of dehydrogenation of NADH in vitro, were also examined under ischemia-mimetic conditions. Conclusion： Our findings anticipate a contribution of both conformational NADH changes and energy transfer from NADH to lipoamide dehydrogenase （LipDH）-bound flavins, to explain observed fluorescence kinetics. Presented spectrally resolved fluorescence lifetime approach provides promising new tool for analysis of mitochondrial NAD （P） H in living cardiomyocytes, and hence for investigation of energy metabolism and mitoehondrial dysfunction at a cellular level.     

Hyaluronic acid-based composite hydrogel in cartilage injury caused by osteoarthritis: Application and mechanism北大核心

BACKGROUND: Hyaluronic acid is a natural polysaccharide and a common glycosaminoglycan in human body. It has the highest concentration in eyes and joints. It is made into hydrogels because of its biocompatibility, degradability, and low immunogenicity, and is widely used in tissue engineering. OBJECTIVE: To introduce the characteristics of various hyaluronic acid composite hydrogels and their application in the repair of cartilage damage caused by osteoarthritis. METHODS: CNKI and Wanfang databases were searched with the key words of “hyaluronic acid, hydrogel, cartilage repair, osteoarthritis” in Chinese. PubMed and Web of Science databases were searched with the key words of “hyaluronic acid, hydrogel, cartilage repair, osteoarthritis” in English. The articles published from January 1995 to July 2020 were searched and further analyzed and summarized. RESULTS AND CONCLUSION: The excellent biological properties of hyaluronic acid hydrogel have made it widely studied in the cartilage repair of osteoarthritis, especially through the combination of biological factors, natural materials, synthetic materials, 3D printing technology, polypeptides, mechanical stimulation, etc., which improved the performance of hyaluronic acid hydrogel and promoted its application in cartilage tissue engineering. Although hyaluronic acid composite hydrogels have been studied more, with the comprehensive development of chemistry, materials, physics, biology and other disciplines in the future, a deeper understanding of the degradation mechanism of hyaluronic acid hydrogels and an exploration of the cartilage damage mechanism in osteoarthritis, the hyaluronic acid composite hydrogel is expected to be designed with high efficiency, no side effects and more suitable for cartilage tissue engineering. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

More than a Single Genome： How Alike are Your Cells？

As hard as it may be to believe, every human starts out as a single cell （around one two-hun- dredth of an inch in size） formed when the right sperm cell meets the ovum in the mother. The sperm and egg each carry a half-set of chromosomes, merging to create a single genome that is a combination of each parent. Since all other ceils from the body are duplicates and clones of this one （with the ex- ception of other egg or sperm cells）, it is common sense that these cells would share a genome, but it appears that common sense is wrong. As we get better at reading and examining human DNA, it is becoming more clear that each of our cells has its own more personal genome, different from the rest of the body. This phenomenon of multiple distinct geneotypes that come from a single cell is called ＂mosaicism＂. We often associate genetic changes and mutations with cancer or disease, but this isnJt always the case. Due to regular wear and tear, as well as specific re-shuffling of the DNA during replication, our cells produce and change their genomes constantly,     

The complete genomic sequence analysis of genotype 4 human astrovirus HASTVgz01 strain in Guangzhou

To analyze the genomic molecular structure and genotype of human astrovirus isolated from infant in Guangzhou of China, the primers were designed based on the genomic sequence of astrovirus from the GenBank and the target sequence were amplified by RT-PCR. Then the PCR-products were cloned to T vector and sequenced. The genomic nucleotide sequences were analyzed by the programs CLUSTAL W and DNASTAR. It was found that the full genomic length of HASTVgz01 strain was 6721 bp and the ORFs were 6558 bp. The 5' and 3' UTR were 82 and 81 nucleotides. The genome included 3 open reading frames (ORFs): ORF1a, ORF1b and ORF2. The 5'-terminal ORF1a started at nucleotide 83 and extended to nucleotide 2845. ORFlb (nt 2785 to nt 4332) overlaped ORFla by 61 nucleotides. The 3'-terminal ORF2 began at nucleotide 4325 and terminated at nucleotide 6640. ORF2 had 2316 nucleotides. Compared with other astrovirus sequences in GenBank, the homology of the amino acid sequence of ORF2 of HASTVgz01 strain with that of serotype 4 was 93% . Homology with other serotypes ranged from 61% to 70% . The complete nucleotide sequence of astrovirus HASTVgz01 strain isolated from Guangzhou in China was 6721 bp in length, GenBank accession NO. DQ344027. Comparing the ORF2 of astrovirus HASTVgz01 with the known sequences of types 1-8 the highest homology was serotype 4 (93%). Comparative sequence analysis of the HASTVgz01 ORF2 with the reported human astrovirus sequences revealed that the isolated astrovirus belongs to genotype (serotype) 4.     

AZ31镁合金材料植入物在兔股骨髁内的降解：Micro-CT评价

BACKGROUND: Magnesium can be degraded voluntarily in vivo, so a second surgery is avoided. However, its alloys have not been widely used in the clinical orthopedics because there is a lack of accurate and reliable methods to assess its degradation in vivo. OBJECTIVE: To explore the degradation of micro-arc-oxidized AZ31 magnesium alloy in the femoral condyle of rabbits based on micro-CT images and relative data. METHODS: Forty micro-arc-oxidized AZ31 magnesium alloys were implanted into the right femoral condyle of 40 New Zealand rabbits. Then 10 right femoral condyles were removed at 5, 10, 15 and 20 weeks after surgery, respectively, to quantitatively analyze and evaluate the degradation of AZ31 magnesium alloys by micro-CT images and relative data. RESULTS AND CONCLUSION: The surface of AZ31 alloys was corroded progressively with dark color and distorted appearance at 5-20 weeks post implantation. Micro-CT images showed that in the first 5 weeks, the degradation was inactive, and at the 10th week, it turned active; at the 15th week, the corrosion pits were obviously increased in number, and the corrosion area and corrosion speed were enlarged and fastened, respectively. Up to the 20th week, the alloy surfaces were full of corrosion pits besides roughness and discontinuity. Relevant data analysis showed that the volume fraction of magnesium alloy was 98.6%, 97.1% and 86.4% at the 5th, 10th and 20th weeks after implantation, respectively, and it had a significant decrease from the 10th to 15th week and from the 15th to 20th week (P < 0.05). Within 15-20 weeks, the volume fraction of magnesium alloy was decreased by 6.5% that was the maximum volume reduction per unit cycle. With the progress of corrosion, the surface continuously became rough and vague, and its surface area was enlarged; the ratio of surface area to volume continuously increased, and there was a significant difference at 15 and 20 weeks (P < 0.05). Because of the increasing number of corrosion pits, the cross-sectional radius decreased, which was reflected by the trabecular thickness decreasing from 1.00 to 0.87 mm. From the view of the slope of curve, the trabecular thickness decreased most rapidly at 10-15 weeks. The mineral density of magnesium alloy continuously decreased from 649.302 to 356.445 mg/cm3 during the whole experiment period (P < 0.05). In addition, the micro-CT image density decreased from 679.710 to 644.947 mg/cm3, but there was no significant difference. To conclude, the degradation speed is peaked at 10-20 weeks after implantation, and the content of magnesium alloys decrease with degradation, but the magnesium density has no significant change. 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程