Methotrexate combined with methylprednisolone for the recovery of motor function and differential gene expression in rats with spinal cord injury

Methylprednisolone is a commonly used drug for the treatment of spinal cord injury, but high doses of methylprednisolone can increase the incidence of infectious diseases. Methotrexate has anti-inflammatory activity and immunosuppressive effects, and can reduce in- flammation after spinal cord injury. To analyze gene expression changes and the molecular mechanism of methotrexate combined with methylprednisolone in the treatment of spinal cord injury, a rat model of spinal cord contusion was prepared using the PinPointTM preci- sion cortical impactor technique. Rats were injected with methylprednisolone 30 mg/kg 30 minutes after injury, and then subcutaneously injected with 0.3 mg/kg methotrexate 1 day after injury, once a day, for 2 weeks. TreadScan gait analysis found that at 4 and 8 weeks after injury, methotrexate combined with methylprednisolone significantly improved hind limb swing time, stride time, minimum longitudinal deviation, instant speed, footprint area and regularity index. Solexa high-throughput sequencing was used to analyze differential gene ex- pression. Compared with methylprednisolone alone, differential expression of 316 genes was detected in injured spinal cord treated with methotrexate and methylprednisolone. The 275 up-regulated genes were mainly related to nerve recovery, anti-oxidative, anti-inflammatory and anti-apoptotic functions, while 41 down-regulated genes were mainly related to proinflammatory and pro-apoptotic functions. These results indicate that methotrexate combined with methylprednisolone exhibited better effects on inhibiting the activity of inflammatory cytokines and enhancing antioxidant and anti-apoptotic effects and thereby produced stronger neuroprotective effects than methotrexate alone. The 316 differentially expressed genes play an important role in the above processes.

Activation of Toll-like receptors signaling in non-small cell lung cancer cell line induced by tumor-associated macrophages

Background： Inflammation is often linked with the progress and poor outcome of lung cancer. The understanding of the relationship between tumor-associated macrophages （TAMs） and lung cancer cells involves in the underlying mechanism of inflammatory cytokine production. Toll-like receptors （TLRs） are engaged in promoting the production of pro-inflammatory cytokines and play an important role in tumor immunology. Methods： To investigate the mechanisms by which TAMs influence the production of pro-inflammatory cytoldnes in lung cancer cells, we established an in vitro coculture system using TAMs and human non- small cell lung cancer （NSCLC） cell line SPC-A1. Levels of interleukin （IL）-113, IL-6 and IL-8 in SPC-A1 were evaluated by RT-PCR and cytometric bead array assay after being cocultured with TAMs. Expression changes of TLRs and TLRs signaling pathway proteins in SPC-Al were further confirmed by RT-PCR and western blot. The level changes of IL-1β, IL-6 and IL-8 in SPC-Al were also detected after the stimulation of TLRs agonists. Results： We found that the phenotype markers of TAMs were highly expressed after stimulating human monocyte cell line THP-1 by phorbol-12-myristate-β-acetate （PMA）. Higher mRNA and supernate secretion levels of IL-1β, IL-6 and IL-8 were detected in SPC-A1 after being eocultured with TAMs. We also found that TLR1, TLR6 and TLR7 were up-regulated in SPC-A1 in the coculture system with TAMs. Meanwhile, TLRs signaling pathway proteins were also significantly activated. Moreover, pre-treatment with agonist ligands for TLR1, TLR6 and TLR7 could dramatically promote inductions of IL-1β, IL-6 and IL-8. Conclusions： These findings demonstrated that TAMs may enhance IL-1β, IL-6 and IL-8 expressions via TLRs signaling pathway. We conclude that TAMs contribute to maintain the inflammation microenvironment and ultimately promote the development and progression of lung cancer.

Characterization of integrons and novel cassette arrays in bacteria from clinical isloates in China,2000-2014

Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays ofintegrons （including class 1, 2, 3 and atypical class 1 integron） from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria （94.1%, 7,364/7,822） while only 5.9% strains were Gram- positive bacteria. Class 1 integrons were detected in 54.2% （3956/7295） Gram-negative strains, aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA 17-aadA5 were detected in 426 Gram- negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.

Prevalence and trends of aminoglycoside resistance in Shigella worldwide, 1999-2010

Shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in Shigella is an emerging problem. Understanding changing resistance patterns is important in determining appropriate antibiotic treatments. This meta-analysis systematically evaluated aminoglycoside resistance in Shigella. A systematic review was constructed based on MEDLINE and EMBASE databases. Randomeffect models or fixed-effect models were used based on P value considering the possibility of heterogeneity between studies for meta-analysis. Data manipulation and statistical analyses were performed using software STATA 11.0. By means of meta-analysis, we found a lower resistance to three kinds of aminoglycosides in the Europe-America areas during the 12 year study period than that of the Asia-Africa areas. Kanamycin resistance was observed to be the most common drug resistance among Shigella isolates with a prevalence of 6.88% （95%CI： 6.36%-7.43%）. Comparison of data from Europe-America and Asia-Africa areas revealed that Shigella flexneri resistance was greater than the resistance calculated for Shigella sonnei. Importantly, Shigella sonnei has played a significant role in aminoglycoside-resistance in recent years. Similarly, data showed that resistance to these drugs in children was higher than the corresponding data of adults. In conclusion, aminoglycoside-resistant Shigella is not an unusual phenomenon worldwide. Distribution in Shigella resistance differs sharply based on geographic areas, periods of time and subtypes. The results from the present study highlight the need for con- tinuous surveillance of resistance and control of antibiotic usage.

Clinical application of simultaneous detection of cystatin C,cathepsin S,and IL-1 in classification of coronary artery disease

Cystatin C,cathepsin S,and IL-1 are three important biomarkers of atherosclerosis.Previous studies emphasized the relationship between individual biomarkers in coronary artery disease（CAD） patients and severity of atherosclerostic lesions of the coronary arteries,while combined cystatin C,cathepsin S,and IL-1 have not been reported for clinical classification of CAD.We aimed to establish a link between cystatin C,cathepsin S,IL-1 and CAD in this cohort study.Totally 112 subjects were enrolled and divided into the stable angina pectoris group,the unstable angina pectoris group and the acute myocardial infarction（AMI） groups,and 50 healthy adults served as controls.The levels of the three biomarkers were detected by ELISA.The results showed that serum level of cystatin C（mg/L） was higher in CAD patients compared with those in the healthy controls（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：1.27±0.18 vs.1.09±0.19 vs.0.91±0.05 vs.0.78±0.07,all P〈0.01）.Cathepsin S（ng/mL） was also significantly different among the groups（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：67.30±8.36 vs.56.90±7.16 vs.49.8±2.72 vs.67.30±8.36,all P〈0.01）.IL-1（pg/mL） was significantly different among the groups as well（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：2.96±0.57 vs.2.46±0.24 vs.2.28±0.09 vs.2.02±0.13,all P〈0.01）.Spearman＇s correlation test revealed positive correlation between cystatin C,cathepsin S,IL-1 and Gensini score（r=0.451,0.491,0.397,respectively）.It is suggested that simultaneous detection of cystatin C,cathepsin S,and IL-1 in serum may be useful in clinical classification and assessment of severity of CAD.

Efficient degradation of aqueous dichloromethane by an enhanced microbial electrolysis cell:Degradation kinetics,microbial community and metabolic mechanisms

Dichloromethane(DCM)has been listed as a toxic and harmful water pollutant,and its re moval needs attention.Microbial electrolysis cells(MECs)are viewed as a promising alterna tive for pollutant removal,which can be strengthened from two aspects:microbial inocula tion and acclimation.In this study,the MEC for DCM degradation was inoculated with the ac tive sludge enhanced by Methylobacterium rhodesianum H13(strain H13)and then acclimated in the form of a microbial fuel cell(MFC).Both the introduction of strain H13 and the initi ation in MFC form significantly promoted DCM degradation.The degradation kinetics were fitted by the Haldane model,with V_(max),K_(h),K_(i)and v_(max)values of 103.2 mg/L/hr,97.8 mg/L268.3 mg/L and 44.7 mg/L/hr/cm^(2),respectively.The cyclic voltammogram implies that DCM redox reactions became easier with the setup of MEC,and the electrochemical impedance spectrogram shows that the acclimated and enriched microbes reduced the charge transfe resistance from the electrode to the electrolyte.In the biofilm,the dominant genera shifted from Geobacter to Hyphomicrobium in acclimation stages.Moreover,Methylobacterium played an increasingly important role.DCM metabolism mainly occurred through the hydrolytic glutathione S-transferase pathway,given that the gene dcmA was identified rather than the dhlA and P450/MO.The exogenous electrons facilitated the reduction of GSSG,directly o indirectly accelerating the GSH-catalyzed dehalogenation.This study provides support fo the construction of an efficient and stable MEC for DCM removal in water environment.

Femtosecond laser trapping dynamics of two-photon absorbing hollow-core nanoparticles

We investigate femtosecond laser trapping dynamics of two-photon absorbing hollow-core nanoparticles with different volume fractions and two-photon absorption(TPA)coefficients.Numerical simulations show that the hollow-core particles with low and high-volume fractions can easily be trapped and bounced by the tightly focused Gaussian laser pulses,respectively.Further studies show that the hollow-core particles with and without TPA can be identified,because the TPA effect enhances the radiation force,and subsequently the longitudinal force destabilizes the trap by pushing the particle away from the focal point.The results may find direct applications in particle sorting and characterizing the TPA coefficient of single nanoparticles.

Reconfigurable nested photonic topological loops

Photonic structures with topological edge states and resonance loops are both important in optical communication systems,but they are usually two separate structures.In order to obtain a photonic system combining properties from both,we design multiple-layer nested photonic topological structures.The nested topological loops not only have topological protection immune to structural disorder and defects,but also possess both the properties of unidirectional propagation and loop resonance.Through mode analysis and simulations,we find that the transport can form diverse circulation loops.Each loop has its own resonance frequencies and can be solely excited in the nested layered structure through choosing its resonance frequencies.As a result,this work shows great application prospects in the area of reconfigurable photonic circuits.

Introduction of graphene oxide-supported multilayer-quantum dots nanofilm into multiplex lateral flow immunoassay:A rapid and ultrasensitive point-of-care testing technique for multiple respiratory viruses

A lateral flow immunoassay(LFA)biosensor that allows the sensitive and accurate identification of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and other common respiratory viruses remains highly desired in the face of the coronavirus disease 2019 pandemic.Here,we propose a multiplex LFA method for the on-site,rapid,and highly sensitive screening of multiple respiratory viruses,using a multilayered film-likefluorescent tag as the performance enhancement and signal amplification tool.This film-like three-dimensional(3D)tag was prepared through the layer-by-layer assembly of highly photostable CdSe@ZnS-COOH quantum dots(QDs)onto the surfaces of monolayer graphene oxide nanosheets,which can provide larger reaction interfaces and specific active surface areas,higher QD loads,and better luminescence and dispersibility than traditional spherical fluorescent microspheres for LFA applications.The constructedfluorescent LFA biosensor can simultaneously and sensitively quantify SARS-CoV-2,influenza A virus,and human adenovirus with low detection limits(8 pg/mL,488 copies/mL,and 471 copies/mL),short assay time(15 min),good reproducibility,and high accuracy.Moreover,our proposed assay has great potential for the early diagnosis of respiratory virus infections given its robustness when validated in real saliva samples.

Optical forces of focused femtosecond laserpulses on nonlinear optical Rayleigh particles

The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the dependence of the optical forces on the magnitudes and signs of the refractive nonlinearities. It is found that the self-focusing effect enhances the trapping ability, whereas the self-defocusing effect leads to the splitting of the potential well at the focal plane and destabilizes the optical trap. Our results show good agreement with the reported experimental observations and provide theoretical support for capturing nonlinear optical particles.

Optically induced rotation of Rayleigh particles by arbitrary photonic spin

Optical trapping techniques hold great interest for their advantages that enable direct handling of nanoparticles. In this work, we study the optical trapping effects of a diffraction-limited focal field possessing an arbitrary photonic spin and propose a convenient method to manipulate the movement behavior of the trapped nanoparticles. In order to achieve controllable spin axis orientation and ellipticity of the tightly focused beam in three dimensions, an efficient method to analytically calculate and experimentally generate complex optical fields at the pupil plane of a high numerical aperture lens is developed. By numerically calculating the optical forces and torques of Rayleigh particles with spherical/ellipsoidal shape, we demonstrate that the interactions between the tunable photonic spin and nanoparticles lead to not only 3D trapping but also precise control of the nanoparticles' movements in terms of stable orientation, rotational orientation, and rotation frequency. This versatile trapping method may open up new avenues for optical trapping and their applications in various scientific fields.

Force measurement goes to femto-Newton sensitivity of single microscopic particle

Highly sensitive force measurements of a single microscopic particle with femto-Newton sensitivity have remained elusive owing to the existence of fundamental thermal noise.Now,researchers have proposed an optically controlled hydrodynamic manipulation method,which can measure the weak force of a single microscopic particle with femto-Newton sensitivity.

Identification and separation of local and nonlocal optical nonlinear refraction effects: theory and experiment

Understanding the nonlinear optical effect of novel materials plays a crucial role in the fields of photonics and optoelectronics.Herein,we theoretically and experimentally investigate the simultaneous presence of third-order locally refractive nonlinearity and thermally induced nonlocal nonlinearity saturation.We present analytical expressions for the closed-aperture Z-scan trace and the number of spatial self-phase modulation(SSPM)rings,which allows one to unambiguously and conveniently separate the contributions of local and nonlocal nonlinear refraction in the case that both effects occur simultaneously.As a test,we study both the local and thermally induced nonlocal nonlinear refraction in fullerene/toluene solution by performing continuous-wave Z-scan and SSPM measurements at two different wavelengths.This work enriches the understanding of the physical mechanism of the optical nonlinear refraction effect in solution dispersions of nanomaterials,which can be exploited for nonlinear photonic devices.