Objective To explore the related factors of postoperative nutritional risk in elderly patients with proximal femoral nail anti rotation(PFNA)internal fixation and establish a prediction model of malnutrition.Methods A total of 574 elderly patients who underwent PFNA internal fixation in the First Medical Center of Chinese PLA General Hospital from January 2021 to June 2024 were included and divided into malnutrition group(n=389)and good nutrition group(n=185).The differences in 39 indicators in aspects of physiological,psychological,social,economic,environmental and medical fields were compared between the 2 groups.Logistic analysis was used to screen the nutritional risk factors,and then a nomogram model was constructed based on these factors.Results Advanced age,lower BMI,higher postoperative Self-Rating Anxiety Scale(SAS)score,less exercise before fracture,being farmers,higher economic pressure,lower preoperative albumin,preprotein and hemoglobin,and lower Barthel index before fracture were independent risk factors for nutritional risk in patients undergoing PFNA internal fixation(P＜0.05).The nomogram prediction model based on the above factors had an AUC value of 0.995(95％CI:0.987～1.000)in predicting the risk of malnutrition in these patients.When the threshold probability＞0.02,this model could be clinically beneficial in predicting the risk of postoperative malnutrition in patients after PFNA internal fixation.Conclusion Our nutritional risk prediction model based on age,BMI,economic pressure,pre-fracture exercise and preoperative albumin and other indicators is constructed for the elderly patients after PFNA internal fixation,and the model has high accuracy and clinical application value.

Objective:To explore the relationship between the morphology of the carotid siphon, its related risk factors, and cerebral blood flow perfusion in patients with arteriosclerotic cerebral small vessel disease (aCSVD), and provide imaging evidence for the etiology of aCSVD.Methods:A total of 130 aCSVD patients hospitalized in the Department of Neurology of the First People′s Hospital of Hefei from March 2022 to June 2024, all of whom underwent multimodal imaging assessments, were enrolled. The baseline data were collected, and the morphology of the carotid siphon was visually evaluated using post-processing of head and neck computed tomography angiography (CTA), which was categorized into U-type ( n=63), C-type ( n=32), and V-type ( n=35). Calcification degree was semi-quantitatively assessed based on transverse CTA images. Cerebral perfusion was measured using magnetic resonance arterial spin labeling. The relationship between different siphon segment morphologies, calcification degrees, their risk factors, and cerebral blood flow perfusion was analyzed using analysis of variance and multinomial Logistic regression. Results:Univariate analysis of the 3 siphon types showed significant differences in low-density lipoprotein cholesterol [U-type (2.44±0.84) mmol/L,V-type (2.21±0.57) mmol/L, C-type (2.89±1.07) mmol/L, F=5.578, P=0.005], calcification degree [Among the 63 cases in the U-type group, 19 cases (30.15%) had mild calcification, 20 cases (31.75%) had moderate calcification, and 24 cases (38.10%) had severe calcification; among the 35 cases in the V-type group, 20 cases (57.14%) had mild calcification, 10 cases (28.57%) had moderate calcification, and 5 cases (14.29%) had severe calcification; among the 32 cases in the C-type group, 12 cases (37.50%) had mild calcification, 14 cases (43.75%) had moderate calcification, and 6 cases (18.75%) had severe calcification; χ2=13.092, P=0.011], and total aCSVD load [modified aCSVD load score: U-type 4.00(1.00, 4.00),V-type 3.00(1.00, 4.00),C-type 2.00(2.00, 4.00), H=9.997, P=0.007]. Multivariate Logistic regression revealed that patients with U-shaped siphons had a significantly higher overall aCSVD load than those with C-shaped siphons, with a regression coefficient of 0.728, and a statistically significant difference ( OR=2.070 ,95% CI 1.026-4.178, P=0.042). Additionally, total brain and white matter cerebral blood flow were decreased in patients with U-type siphons compared to those with C-type and V-type, primarily involving bilateral superior frontal gyri, left orbital frontal gyrus, and left straight gyrus regions (false discovery rate correction, P<0.05). Conclusions:The imaging manifestations of aCSVD are closely related to the shape of the internal carotid artery siphon.The U type siphon is more likely to lead to hemodynamic changes, resulting in decreased global and regional cerebral blood flow, and demonstrating a higher overall burden of aCSVD, which has certain clinical reference value for assessing the etiology of aCSVD.

Objective To investigate the predictive value of serum lipoprotein-associated phospholipase A2(Lp-PLA2)and homocysteine(Hcy)combined with white matter hyperintensities(WMH)for cognitive impairment in patients with cerebral small vessel disease(CSVD).Methods A total of 240 patients with CSVD were selected.According to the Montreal Cognitive Assessment(MoCA)scale,all subjects were divided into the non-cognitive impairment group(MoCA≥26 points,120 cases)and the cognitive impairment group(MoCA＜26 points,120 cases).Paraventricular white matter high signal(PWMHs)and deep white matter high signal(DWMHs)were scored by Fazekas scale.The sum of the two parts was the total score,and the severity of DWMHs was graded by the score.The basic information,serum Lp-PLA2,Hcy level and severity of WMH were compared between the two groups.Logistic regression was applied to analyze influencing factors of cognitive impairment in CSVD patients.The predictive value of serum level of Lp-PLA2 and Hcy and WMH for cognitive impairment in CSVD patients was analyzed by receiver operating characteristic(ROC)curve.Results Compared with the non-cognitive impairment group,patients of the cognitive impairment group were older,had higher serum levels of Lp-PLA2 and Hcy,and had more severe of WMH(P＜0.05).Results of Logistic regression analysis showed that serum Lp-PLA2,Hcy levels and severity of WMH were influencing factors for cognitive impairment of patients with CSVD(P＜0.05).The results of ROC curve analysis showed that the area under the curve of serum Lp-PLA2,Hcy level combined with severity of WMH predicting cognitive impairment in patents with CSVD was 0.812,the sensitivity was 81.7%and the specificity was 71.7%(P＜0.05).Conclusion Patients with cognitive impairment caused by CSVD have higher serum levels of Lp-PLA2 and Hcy,and more severe WMH.The combination of the three has a relatively high predictive value for cognitive impairment in patents with CSVD.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective To investigate the predictive value of serum lipoprotein-associated phospholipase A2(Lp-PLA2)and homocysteine(Hcy)combined with white matter hyperintensities(WMH)for cognitive impairment in patients with cerebral small vessel disease(CSVD).Methods A total of 240 patients with CSVD were selected.According to the Montreal Cognitive Assessment(MoCA)scale,all subjects were divided into the non-cognitive impairment group(MoCA≥26 points,120 cases)and the cognitive impairment group(MoCA＜26 points,120 cases).Paraventricular white matter high signal(PWMHs)and deep white matter high signal(DWMHs)were scored by Fazekas scale.The sum of the two parts was the total score,and the severity of DWMHs was graded by the score.The basic information,serum Lp-PLA2,Hcy level and severity of WMH were compared between the two groups.Logistic regression was applied to analyze influencing factors of cognitive impairment in CSVD patients.The predictive value of serum level of Lp-PLA2 and Hcy and WMH for cognitive impairment in CSVD patients was analyzed by receiver operating characteristic(ROC)curve.Results Compared with the non-cognitive impairment group,patients of the cognitive impairment group were older,had higher serum levels of Lp-PLA2 and Hcy,and had more severe of WMH(P＜0.05).Results of Logistic regression analysis showed that serum Lp-PLA2,Hcy levels and severity of WMH were influencing factors for cognitive impairment of patients with CSVD(P＜0.05).The results of ROC curve analysis showed that the area under the curve of serum Lp-PLA2,Hcy level combined with severity of WMH predicting cognitive impairment in patents with CSVD was 0.812,the sensitivity was 81.7%and the specificity was 71.7%(P＜0.05).Conclusion Patients with cognitive impairment caused by CSVD have higher serum levels of Lp-PLA2 and Hcy,and more severe WMH.The combination of the three has a relatively high predictive value for cognitive impairment in patents with CSVD.

Objective:To explore the relationship between the morphology of the carotid siphon, its related risk factors, and cerebral blood flow perfusion in patients with arteriosclerotic cerebral small vessel disease (aCSVD), and provide imaging evidence for the etiology of aCSVD.Methods:A total of 130 aCSVD patients hospitalized in the Department of Neurology of the First People′s Hospital of Hefei from March 2022 to June 2024, all of whom underwent multimodal imaging assessments, were enrolled. The baseline data were collected, and the morphology of the carotid siphon was visually evaluated using post-processing of head and neck computed tomography angiography (CTA), which was categorized into U-type ( n=63), C-type ( n=32), and V-type ( n=35). Calcification degree was semi-quantitatively assessed based on transverse CTA images. Cerebral perfusion was measured using magnetic resonance arterial spin labeling. The relationship between different siphon segment morphologies, calcification degrees, their risk factors, and cerebral blood flow perfusion was analyzed using analysis of variance and multinomial Logistic regression. Results:Univariate analysis of the 3 siphon types showed significant differences in low-density lipoprotein cholesterol [U-type (2.44±0.84) mmol/L,V-type (2.21±0.57) mmol/L, C-type (2.89±1.07) mmol/L, F=5.578, P=0.005], calcification degree [Among the 63 cases in the U-type group, 19 cases (30.15%) had mild calcification, 20 cases (31.75%) had moderate calcification, and 24 cases (38.10%) had severe calcification; among the 35 cases in the V-type group, 20 cases (57.14%) had mild calcification, 10 cases (28.57%) had moderate calcification, and 5 cases (14.29%) had severe calcification; among the 32 cases in the C-type group, 12 cases (37.50%) had mild calcification, 14 cases (43.75%) had moderate calcification, and 6 cases (18.75%) had severe calcification; χ2=13.092, P=0.011], and total aCSVD load [modified aCSVD load score: U-type 4.00(1.00, 4.00),V-type 3.00(1.00, 4.00),C-type 2.00(2.00, 4.00), H=9.997, P=0.007]. Multivariate Logistic regression revealed that patients with U-shaped siphons had a significantly higher overall aCSVD load than those with C-shaped siphons, with a regression coefficient of 0.728, and a statistically significant difference ( OR=2.070 ,95% CI 1.026-4.178, P=0.042). Additionally, total brain and white matter cerebral blood flow were decreased in patients with U-type siphons compared to those with C-type and V-type, primarily involving bilateral superior frontal gyri, left orbital frontal gyrus, and left straight gyrus regions (false discovery rate correction, P<0.05). Conclusions:The imaging manifestations of aCSVD are closely related to the shape of the internal carotid artery siphon.The U type siphon is more likely to lead to hemodynamic changes, resulting in decreased global and regional cerebral blood flow, and demonstrating a higher overall burden of aCSVD, which has certain clinical reference value for assessing the etiology of aCSVD.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Aim To explore the mechanism of oxiracetam promoting neurogenesis and migration in rats with cer-ebral infarction through stromal cell-derived factor-1α(SDF-1α)/C-X-C chemokine receptor 4(CXCR4)pathway.Methods 100 SD rats were randomly divided into control group,cerebral ischemia(CI)group,oxiracetam(200 mg/kg)group,and oxiracetam(200 mg/kg)+AMD3100(5 mg/kg)group,with 25 rats in each group.Electrocoagulation was used to create rat model of local permanent cerebral infarction.After 1,7 and 14 days of modeling,neurological deficits were scored,TTC staining was used to detect the volume of cerebral infarction,Nissl staining was used to detect cell surviv-al in the infarcted area,Western blot was used to detect SDF-1α and CXCR4 protein levels in ischemic zone.After 1～7 days of modeling,BrdU(50 mg/kg)was continuously injected intraperitoneally.After 14 days,immunofluorescence double staining was used to detect the number of BrdU+Nestin+and BrdU+DCX+cells in the SVZ region.5 days before modeling,retroviruses carrying GFP were injected into the SVZ region.After 14 days,immunofluorescence double stai-ning was used to detect the number of GFP+DCX+,GFP+MAP-2+and GFP+GFAP+cells in infarction area.C17.2 cells were divided into control group,oxygen-glucose deprivation(OGD)group,oxiracetam(final concentration:200 mg/L)group,and oxiracetam(final concentration:200 mg/L)+AMD3100(final concentration:100 μmol/L)group.OGD was used to create cell CI model.After 12 hours,immunofluorescence double staining was used to detect the number of Br-dU+/Nestin+and BrdU+/MAP-2+cells,Transwell experiment was used to detect cell migration,Western blot was used to detect SDF-1α and CXCR4 protein levels in cell culture supernatant.Results Animal experiment results showed:compared with control group,mNSS score in CI group was increased,cerebral infarction volume was increased,the number of surviving cells in infarcted area was decreased,SDF-1α and CXCR4 protein levels were increased,the number of GFP+DCX+,GFP+MAP-2+and GFP+GFAP+cells in SVZ region were increased(P＜0.05);compared with CI group,mNSS score in oxiracetam group was decreased,cerebral infarction volume was decreased,the number of surviving cells in infarc-ted area was increased,SDF-1α and CXCR4 protein levels were increased,the number of GFP+DCX+,GFP+MAP-2+and GFP+GFAP+cells in SVZ region were increased,the number of GFP+DCX+,GFP+MAP-2+and GFP+GFAP+cells in in-farcted area were increased(P＜0.05);compared with oxiracetam group,mNSS score in oxiracetam+AMD3100 group was increased,cerebral infarction volume was increased,the number of surviving cells in infarcted area was decreased,CXCR4 protein level was decreased,the number of GFP+DCX+,GFP+MAP-2+and GFP+GFAP+cells in the SVZ region were de-creased(P＜0.05).Cell experiment results showed:compared with control group,the number of BrdU+/Nestin+and Br-dU+/MAP-2+cells in OGD group were increased,the number of cell migration,SDF-1α and CXCR4 protein levels in cell culture supernatant were increased(P＜0.05);compared with OGD group,the number of BrdU+/Nestin+and BrdU+/MAP-2+cells in oxiracetam group were increased,the number of cell migration,SDF-1α and CXCR4 protein levels in cell culture supernatant were increased(P＜0.05);compared with oxiracetam group,the number of BrdU+/Nestin+and BrdU+/MAP-2+cells in oxiracetam+AMD3100 group were decreased,the number of cell migration,CXCR4 protein level in cell culture supernatant were decreased(P＜0.05).Conclusion Oxiracetam may promote the migration of neural stem cells from the SVZ region to the ischemic zone,promoting neurogenesis and functional recovery in rats with cerebral infarction by activating SDF-1α/CXCR4 pathway.