Objective To observe the value of deep learning image reconstruction(DLIR)algorithm in brain CT perfusion(CTP)using a protocol of 70 kVp and 40 ml contrast agent dose.Methods Totally 105 patients with suspected acute ischemic stroke(AIS)were prospectively enrolled and randomly divided into 3 groups,who underwent standard dose CTP scanning with 80 kVp and 150 mA combined with reconstruction as adaptive statistic iterative reconstruction V(ASIR-V)at 50％level(CN group,n=35),low dose(LD)scanning with 70 kVp and 100 mA combined with DLIR reconstruction at the highest level(DLIR-H)(LD group,n=35),or ultra-low dose(ULD)scanning with 70 kVp and 70 mA combined with DLIR-H reconstruction(ULD group,n=35).Radiation doses were compared among 3 groups.CT values and standard deviations(SDCT)of ROI of gray matter and white matter in the frontal,parietal and temporal lobes were measured.Signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)between gray and white matter were calculated and compared among groups.Then pseudo-color images of cerebral blood volume(CBV),cerebral blood flow(CBF),mean transit time(MTT)and time to maximum of the tissue residual function(Tmax)were generated.The imaging quality of CTP pseudo-color images was evaluated,and the compatibility of the subjective scores within every kind of CTP pseudo-color images were assessed using Kappa test.Quantitative perfusion parameters were measured and compared among groups.Results Compared with CN group,both LD and ULD groups demonstrated significantly reduced volume CT dose index(CTDIvol),dose-length product(DLP)and effective dose(ED)(all adjusted P＜0.05).In ULD group,SDCT of white matter in frontal,parietal and temporal lobes were higher than those in CN group,and SDCT of white matter in parietal lobe was also higher than that in LD group(all adjusted P＜0.05).No significant difference of SDCT of gray matter was observed among groups(all P＞0.05).SNR of white matter in parietal and temporal lobes in both LD and ULD groups were lower than those in CN group(all P＜0.05),while no significant difference of SNR of white matter in frontal lobe,nor of gray matter in frontal,parietal and temporal lobes was found among groups(all P＞0.05).CNR of gray and white matter in the frontal,parietal and temporal lobes were not significantly different among groups(all P＞0.05).High consistency of inter-observer subjective scores of CBV maps,CBF maps and Tmax maps(Kappa of 0.623,0.644 and 0.638,respectively)were noticed,which of MTT maps had moderate consistency(Kappa=0.560).No significant difference of intra-obsever subjective scores of CTP pseudo-color images was found among groups(all P＞0.05).CBV,CBF,MTT and Tmax values of gray and white matter in frontal,parietal and temporal lobes were not significantly different among groups(all P＞0.05).Conclusion DLIR algorithm applicated in low radiation dose and reduced contrast agent dosage might ensure imaging quality.

Aim To investigate the effect of exosomes derived from bone marrod-derived mesenchymal stem cells(BMSCs)on dexamethasone-induced C2C12 muscular canal atrophy.Methods(1)C57BL/6J mouse bone marrow mesenchymal stem cells were isola-ted and cultured by whole bone marrow adhesion meth-od.(2)Extraction and identification of BMSCs EXOs were performed.(3)Myogenic differentiation of C2C12 cells was carried out.(4)The successfully differentia-ted myotubes were divided into the control group(cul-tured in 2％equine serum medium for 48 h),dexam-ethasone group(dexamethasone,DEX,10 μmol·L-1 concentration of DEX interfered with myotubes for 48 h),and exosomes group(exosomes,EXOs,interfered with myotubes for 48 h),exosome inhibitor group(exo-somes extracted from BMSCs after 10 μm GW4869 in-tervention,interfered with myotubes for 48 h).48 h later,the morphology and diameter of muscle tubes were observed and measured by microscope.Cell via-bility of each group was detected by CCK-8 method.The expression levels of atrogin-1 and MuRF-1,myo-genic differentiation antigen(MYOD)in each group were detected by Western blot.Results BMSCs were long spusiform,and BMSCS-EXOS showed a circular bilayer structure under transmission electron microsco-py,with a diameter of about 200 nm.CD9,CD63 and CD81 were highly expressed.Compared with the con-trol group,cell activity in DEX group decreased(P＜0.01),diameter of myotubes decreased(P＜0.01),expressions of atrogin-1(P＜0.05)and MuRF-1(P＜0.01)were significantly up-regulated,and expression of MYOD(P＜0.01)was significantly down-regula-ted.Compared with the DEX group,cell activity in the BMSCs-EXOs group increased(P＜0.01),diameter of myotubes increased(P＜0.01),expressions of atrogin-1(P＜0.05)and MuRF-1(P＜0.01)were signifi-cantly down-regulated,and expression of MYOD(P＜0.01)was up-regulated.Compared with the BMSCs-EXOs group,cell activity of the BMSCs-EXOs(GW4869)group decreased(P＜0.05),diameter of myotubes decreased(P＜0.01),expressions of atrog-in-1(P＜0.05)and MuRF-1(P＜0.05)were up-regulated,and expression of MYOD(P＜0.01)was down-regulated.Conclusion Bone marrow mesen-chymal stem cell-derived exosomes(BM-MSCs-EXOs)inhibit dexamethasone-induced C2C12 muscle tube at-rophy.

Aim To study whether intravenous injec-tion of miR-129-3p mimetic(agomir)can resist bone loss caused by hind limb disuse,and to provide new i-deas for preventing bone loss in microgravity environ-ment.Methods Forty-eight C57BL/6J male mice were randomly divided into the control group(CON),tail suspension model group(TS),tail suspension+miR-129-3p agomir administration group(miRNA)and tail suspension+miR-129-3p negative sequence agomir control group(NC).The miRNA group was given 4 mg·kg-1 miR-129-3p agomir by intravenous injection into the medial canthus twice a week.The NC agomir group were consistent with those in the miR-129-3p agomir group,and the CON and TS groups were given only equal volumes of normal saline.After four weeks,all mice were sacrificed and samples were collected.Micro-CT scan of femur,three-point femur bending test,serum bone metabolism index detection,oxidative stress index detection and osteogenesis-related protein expression analysis in bone tissue were per-formed.Results After four weeks,the number of tra-becular bone in the TS group was significantly re-duced,and Tb.BMD,Tb.Th,Tb.N,Tb.BS/TV and Tb.BV/TV were significantly lower than those in the CON group(P＜0.01).While Tb.Sp TS group was significantly higher than the CON group(P＜0.05),the maximum load and flexural strength of the femur significantly decreased(P＜0.01),the content of ser-um bone formation index PINP was significantly lower than that of the CON group(P＜0.01),and the con-tent of bone resorption index CTX-I was significantly higher than that of the CON group(P＜0.01),the content of serum oxidative damage indexes 8-iso-PGF2α and 8-OHdG significantly increased(P＜0.01),and the expression of osteogenesis-related pro-teins in bone tissue markedly decreased(P＜0.01).However,the increase or decrease of all indexes in miRNA group was significantly lower than that in TS group.Conclusions miR-129-3p mimetic can signifi-cantly reduce bone loss caused by hind limb disuse.This experiment provides a new idea and method for preventing bone loss in microgravity environment.

Aim To evaluate the ameliorative effects of different ratios of Renshen-Huangjing(RH) on SPS-induced PTSD-like behaviors in mice,and to investi-gate the action mechanism using bioinformatics analysis and experimental studies.Methods The aqueous ex-tract was extracted in four ratios of RH in a total weight of 60 g,i.e.1∶0(RH1),2∶1(RH2),1∶2(RH3),and 0∶1(RH4).The extraction rates of Rg1,Rb1,and polysaccharides from different ratios of RH were then detected using UPLC-UV method.The SPS model was established,and RH1,RH2,RH3 and RH4(400 mg·kg-1)were administered by intragas-tric gavage for 14 day,followed by behavioral tests to e-valuate the PTSD-like behaviors.The serum CORT,IL-1β and IL-10 were determined by ELISA.The possible targets of action were analyzed using bioinformatics.The expression levels of Calpain-1,PSD95,BDNF and GluN2B in the hippocampus were detected by Western blot.Results The SPS model induced PTSD-like be-haviors in mice.Serum levels of CORT and IL-1β in-creased and level of IL-10 decreased in SPS model.After treatment with different ratios of RHs,RH2 showed the best therapeutic effect,which was manifes-ted in the suppression of PTSD-like behaviors,the re-duction of CORT and IL-1β levels,and the promotion of IL-10 levels;160 overlapping targets might explain the therapeutic effects of RH on PTSD,and these tar-gets were enriched in inhibiting synaptic damage,exer-ting antioxidant properties and suppressing neuroin-flammation,respectively.RH2 prevented the SPS-in-duced decrease in the expression of Calpain-1,PSD95,BDNF and the elevation of GluN2B.Molecular docking showed strong binding of Rg1 and Rb1 to Calpain-1,PSD95,and BDNF,respectively.Conclusions The a-queous extract of RH in a 2∶1 ratio can more effec-tively prevent SPS-induced PTSD-like behaviors,and its effect may be related to targets such as Calpain-1,PSD95,BDNF and GluN2B.

Objective To observe the value of deep learning image reconstruction(DLIR)algorithm in brain CT perfusion(CTP)using a protocol of 70 kVp and 40 ml contrast agent dose.Methods Totally 105 patients with suspected acute ischemic stroke(AIS)were prospectively enrolled and randomly divided into 3 groups,who underwent standard dose CTP scanning with 80 kVp and 150 mA combined with reconstruction as adaptive statistic iterative reconstruction V(ASIR-V)at 50％level(CN group,n=35),low dose(LD)scanning with 70 kVp and 100 mA combined with DLIR reconstruction at the highest level(DLIR-H)(LD group,n=35),or ultra-low dose(ULD)scanning with 70 kVp and 70 mA combined with DLIR-H reconstruction(ULD group,n=35).Radiation doses were compared among 3 groups.CT values and standard deviations(SDCT)of ROI of gray matter and white matter in the frontal,parietal and temporal lobes were measured.Signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)between gray and white matter were calculated and compared among groups.Then pseudo-color images of cerebral blood volume(CBV),cerebral blood flow(CBF),mean transit time(MTT)and time to maximum of the tissue residual function(Tmax)were generated.The imaging quality of CTP pseudo-color images was evaluated,and the compatibility of the subjective scores within every kind of CTP pseudo-color images were assessed using Kappa test.Quantitative perfusion parameters were measured and compared among groups.Results Compared with CN group,both LD and ULD groups demonstrated significantly reduced volume CT dose index(CTDIvol),dose-length product(DLP)and effective dose(ED)(all adjusted P＜0.05).In ULD group,SDCT of white matter in frontal,parietal and temporal lobes were higher than those in CN group,and SDCT of white matter in parietal lobe was also higher than that in LD group(all adjusted P＜0.05).No significant difference of SDCT of gray matter was observed among groups(all P＞0.05).SNR of white matter in parietal and temporal lobes in both LD and ULD groups were lower than those in CN group(all P＜0.05),while no significant difference of SNR of white matter in frontal lobe,nor of gray matter in frontal,parietal and temporal lobes was found among groups(all P＞0.05).CNR of gray and white matter in the frontal,parietal and temporal lobes were not significantly different among groups(all P＞0.05).High consistency of inter-observer subjective scores of CBV maps,CBF maps and Tmax maps(Kappa of 0.623,0.644 and 0.638,respectively)were noticed,which of MTT maps had moderate consistency(Kappa=0.560).No significant difference of intra-obsever subjective scores of CTP pseudo-color images was found among groups(all P＞0.05).CBV,CBF,MTT and Tmax values of gray and white matter in frontal,parietal and temporal lobes were not significantly different among groups(all P＞0.05).Conclusion DLIR algorithm applicated in low radiation dose and reduced contrast agent dosage might ensure imaging quality.

Aim To evaluate the ameliorative effects of different ratios of Renshen-Huangjing(RH) on SPS-induced PTSD-like behaviors in mice,and to investi-gate the action mechanism using bioinformatics analysis and experimental studies.Methods The aqueous ex-tract was extracted in four ratios of RH in a total weight of 60 g,i.e.1∶0(RH1),2∶1(RH2),1∶2(RH3),and 0∶1(RH4).The extraction rates of Rg1,Rb1,and polysaccharides from different ratios of RH were then detected using UPLC-UV method.The SPS model was established,and RH1,RH2,RH3 and RH4(400 mg·kg-1)were administered by intragas-tric gavage for 14 day,followed by behavioral tests to e-valuate the PTSD-like behaviors.The serum CORT,IL-1β and IL-10 were determined by ELISA.The possible targets of action were analyzed using bioinformatics.The expression levels of Calpain-1,PSD95,BDNF and GluN2B in the hippocampus were detected by Western blot.Results The SPS model induced PTSD-like be-haviors in mice.Serum levels of CORT and IL-1β in-creased and level of IL-10 decreased in SPS model.After treatment with different ratios of RHs,RH2 showed the best therapeutic effect,which was manifes-ted in the suppression of PTSD-like behaviors,the re-duction of CORT and IL-1β levels,and the promotion of IL-10 levels;160 overlapping targets might explain the therapeutic effects of RH on PTSD,and these tar-gets were enriched in inhibiting synaptic damage,exer-ting antioxidant properties and suppressing neuroin-flammation,respectively.RH2 prevented the SPS-in-duced decrease in the expression of Calpain-1,PSD95,BDNF and the elevation of GluN2B.Molecular docking showed strong binding of Rg1 and Rb1 to Calpain-1,PSD95,and BDNF,respectively.Conclusions The a-queous extract of RH in a 2∶1 ratio can more effec-tively prevent SPS-induced PTSD-like behaviors,and its effect may be related to targets such as Calpain-1,PSD95,BDNF and GluN2B.

Aim To investigate the effect of exosomes derived from bone marrod-derived mesenchymal stem cells(BMSCs)on dexamethasone-induced C2C12 muscular canal atrophy.Methods(1)C57BL/6J mouse bone marrow mesenchymal stem cells were isola-ted and cultured by whole bone marrow adhesion meth-od.(2)Extraction and identification of BMSCs EXOs were performed.(3)Myogenic differentiation of C2C12 cells was carried out.(4)The successfully differentia-ted myotubes were divided into the control group(cul-tured in 2％equine serum medium for 48 h),dexam-ethasone group(dexamethasone,DEX,10 μmol·L-1 concentration of DEX interfered with myotubes for 48 h),and exosomes group(exosomes,EXOs,interfered with myotubes for 48 h),exosome inhibitor group(exo-somes extracted from BMSCs after 10 μm GW4869 in-tervention,interfered with myotubes for 48 h).48 h later,the morphology and diameter of muscle tubes were observed and measured by microscope.Cell via-bility of each group was detected by CCK-8 method.The expression levels of atrogin-1 and MuRF-1,myo-genic differentiation antigen(MYOD)in each group were detected by Western blot.Results BMSCs were long spusiform,and BMSCS-EXOS showed a circular bilayer structure under transmission electron microsco-py,with a diameter of about 200 nm.CD9,CD63 and CD81 were highly expressed.Compared with the con-trol group,cell activity in DEX group decreased(P＜0.01),diameter of myotubes decreased(P＜0.01),expressions of atrogin-1(P＜0.05)and MuRF-1(P＜0.01)were significantly up-regulated,and expression of MYOD(P＜0.01)was significantly down-regula-ted.Compared with the DEX group,cell activity in the BMSCs-EXOs group increased(P＜0.01),diameter of myotubes increased(P＜0.01),expressions of atrogin-1(P＜0.05)and MuRF-1(P＜0.01)were signifi-cantly down-regulated,and expression of MYOD(P＜0.01)was up-regulated.Compared with the BMSCs-EXOs group,cell activity of the BMSCs-EXOs(GW4869)group decreased(P＜0.05),diameter of myotubes decreased(P＜0.01),expressions of atrog-in-1(P＜0.05)and MuRF-1(P＜0.05)were up-regulated,and expression of MYOD(P＜0.01)was down-regulated.Conclusion Bone marrow mesen-chymal stem cell-derived exosomes(BM-MSCs-EXOs)inhibit dexamethasone-induced C2C12 muscle tube at-rophy.

Aim To study whether intravenous injec-tion of miR-129-3p mimetic(agomir)can resist bone loss caused by hind limb disuse,and to provide new i-deas for preventing bone loss in microgravity environ-ment.Methods Forty-eight C57BL/6J male mice were randomly divided into the control group(CON),tail suspension model group(TS),tail suspension+miR-129-3p agomir administration group(miRNA)and tail suspension+miR-129-3p negative sequence agomir control group(NC).The miRNA group was given 4 mg·kg-1 miR-129-3p agomir by intravenous injection into the medial canthus twice a week.The NC agomir group were consistent with those in the miR-129-3p agomir group,and the CON and TS groups were given only equal volumes of normal saline.After four weeks,all mice were sacrificed and samples were collected.Micro-CT scan of femur,three-point femur bending test,serum bone metabolism index detection,oxidative stress index detection and osteogenesis-related protein expression analysis in bone tissue were per-formed.Results After four weeks,the number of tra-becular bone in the TS group was significantly re-duced,and Tb.BMD,Tb.Th,Tb.N,Tb.BS/TV and Tb.BV/TV were significantly lower than those in the CON group(P＜0.01).While Tb.Sp TS group was significantly higher than the CON group(P＜0.05),the maximum load and flexural strength of the femur significantly decreased(P＜0.01),the content of ser-um bone formation index PINP was significantly lower than that of the CON group(P＜0.01),and the con-tent of bone resorption index CTX-I was significantly higher than that of the CON group(P＜0.01),the content of serum oxidative damage indexes 8-iso-PGF2α and 8-OHdG significantly increased(P＜0.01),and the expression of osteogenesis-related pro-teins in bone tissue markedly decreased(P＜0.01).However,the increase or decrease of all indexes in miRNA group was significantly lower than that in TS group.Conclusions miR-129-3p mimetic can signifi-cantly reduce bone loss caused by hind limb disuse.This experiment provides a new idea and method for preventing bone loss in microgravity environment.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective:To analyze the utilization of pre-exposure prophylaxis (PrEP) service against HIV and related factors in young men who have sex with men (MSM) in Hangzhou.Methods:A cross-sectional study design was used in this questionnaire survey in young MSM recurited through local MSM social organization in Hangzhou from September 2022 to March 2023. The estimated sample size was 242. The information about the social-demographic characteristics, behavioral characteristics, utilization of the post exposure prophylaxis (PEP) service, awareness and utilization of PrEP service of the young MSM were collected. Logistic regression model was used to analyze the related factors of the PrEP utilization.Results:A total of 273 young MSM aged 16- 24 years were surveyed in the study. A total for 20.1% (55/273) of them had used PrEP service. Multivariate logistic regression analysis showed that the factors related to PrEP service utilization included age 16-20 years (a OR=3.03, 95% CI:1.12-8.20), education level of senior high school or below (a OR=2.83, 95% CI:1.09-7.35), full-time/part-time work (a OR=3.25, 95% CI: 1.26-8.38), homosexual activity in the past 6 months (a OR=6.71, 95% CI:1.84-24.55), inquiring medical staff about PrEP (a OR=4.71, 95% CI:1.99-11.13) and PEP service use (a OR=6.09, 95% CI:2.69-13.81). Conclusions:The utilization rate of PrEP service was low in young MSM in Hangzhou. It is necessary to strengthen the health education about PrEP and improve the undertanding of PrEP and service capability of medical staff to promote the utilization of PrEP service in young MSM.