Objectives: Enlarged perivascular spaces in the basal ganglia (BG-EPVS) share common vascular risk factors with atherosclerosis. However, little is known about the relationship between steno-occlusive middle cerebral artery (MCA) and BG-EPVS. In this cross-sectional study, we aimed to test the hypothesis that severe MCA stenosis or occlusion is associated with increased MRI-visible BG-EPVS. Methods: We retrospectively reviewed 112 patients with a steno-occlusive MCA from Fujian Medical University Union Hospital between January 2014 and December 2018. We rated BG-EPVS, white matter hyperintensities (WMH), and lacunes as markers of cerebral small vessel disease (CSVD) on magnetic resonance image (MRI). The severity of steno-occlusive MCA was assessed by computed tomography angiography (CTA) and was classified into moderate (50-69%), severe (70-99%), and occlusion (100%). We evaluated the association of steno-occlusive MCA for >10 BG-EPVS using logistic regression model adjusted for age, gender, hypertension, MR-visible WMH, and lacunes. We also compared the number of BG-EPVS between the affected side and unaffected side in patients with only unilateral steno-occlusive MCA. Results: In multivariable logistic regression analysis, age (OR = 1.07, 95%CI: 1.03-1.13, p = 0.003), hypertension (OR = 2.77, 95%CI: 1.02-7.51, p = 0.046), severe MCA stenosis (OR = 3.65, 95%CI: 1.12-11.87, p = 0.032), or occlusion (OR = 3.67, 95%CI: 1.20-11.27, p = 0.023) were significantly associated with >10 BG-EPVS. The number of BG-EPVS in the affected side was higher than the unaffected side in patients with severe MCA stenosis (12 [9-14] vs. 8 [6-11], p = 0.001) or occlusion (11 [7-14] vs. 8 [5-11], p = 0.028). Conclusions: BG-EPVS were more prevalent in patients with severe MCA atherosclerosis. Our findings suggest a biological link between severe steno-occlusive MCA and increased BG-EPVS. These results need confirmation in prospective studies.

Background Patients with cardiovascular comorbidities are at high risk of poor outcome from COVID-19. However, how the burden (number) of vascular risk factors influences the risk of severe COVID-19 disease remains unresolved. Our aim was to investigate the association of severe COVID-19 illness with vascular risk factor burden. Methods We included 164 (61.8 ± 13.6 years) patients with COVID-19 in this retrospective study. We compared the difference in clinical characteristics, laboratory findings and chest computed tomography (CT) findings between patients with severe and non-severe COVID-19 illness. We evaluated the association between the number of vascular risk factors and the development of severe COVID-19 disease, using a Cox regression model. Results Sixteen (9.8%) patients had no vascular risk factors; 38 (23.2%) had 1; 58 (35.4%) had 2; 34 (20.7%) had 3; and 18 (10.9%) had ≥4 risk factors. Twenty-nine patients (17.7%) experienced severe COVID-19 disease with a median (14 [7–27] days) duration between onset to developing severe COVID-19 disease, an event rate of 4.47 per 1000-patient days (95%CI 3.10–6.43). Kaplan-Meier curves showed a gradual increase in the risk of severe COVID-19 illness (log-rank P < 0.001) stratified by the number of vascular risk factors. After adjustment for age, sex, and comorbidities as potential confounders, vascular risk factor burden remained associated with an increasing risk of severe COVID-19 illness. Conclusions Patients with increasing vascular risk factor burden have an increasing risk of severe COVID-19 disease, and this population might benefit from specific COVID-19 prevention (e.g., self-isolation) and early hospital treatment measures.

Objective To investigate the effects of adipose-derived stem cell(ADSC) on the Neurocan expression in rat with cerebral ischemia. Methods 54 clean class adult male Sprague-Dawley rats were selected and randomly divided into the sham operation group,model group(middle cerebral arterial embolism) and ADSC group(ADSC transplantation after middle cere-bral arterial embolism),18 cases in each group. The middle cerebral arterial embolism model adopted the modified Zea-Longa line embolism method. Before ADSC transplantation,diamidino-2-phenylindole (DAPI) labeling was performed. The ADSC group was injected with ADSC(1×106 cells) by lateral ventricle on 1 d after successful model establishment. Rats were sacrificed for taking the brain on postoperative 7,14,28 d and the Neurocan protein expression was detected by using the immunofluorescence and Western blot. Results The Neurocan expression of the brain tissues on postoperative 7 ,14 d in the model group was significantly increased and showed the sheet irregular distribution,which was decreased on 28 d,but still higher than that in the sham operation group,the differences were statistically significant(P<0.05). The Neurocan expression of the brain tissues on postoperative 7,14 d in the ADSC group was significantly decreased,moreover which continued to 28 d and showed the statistical difference compared with the model group(P<0.05). Conclusion The ADSC transplantation can decrease the Neurocan expression in the brain ischemic tissues and reduce the scar generation ,which provides the enabling environment for late nerve axons maturity and function estab-lishment,and can promote the restoration of neural function.

BACKGROUND: Transplantation with bone marrow-derived mesenchymal stem cells (BMSCs) improves the survival of neurons and axonal outgrowth after stroke remains undetermined. Here, we investigated whether PI3K/AKT signaling pathway is involved in these therapeutic effects of BMSCs. METHODOLOGY/PRINCIPAL FINDINGS: (1) BMSCs and cortical neurons were derived from Sprague-Dawley rats. The injured neurons were induced by Oxygen-Glucose Deprivation (OGD), and then were respectively co-cultured for 48 hours with BMSCs at different densities (5×10(3), 5×10(5)/ml) in transwell co-culture system. The average length of axon and expression of GAP-43 were examined to assess the effect of BMSCs on axonal outgrowth after the damage of neurons induced by OGD. (2) The injured neurons were cultured with a conditioned medium (CM) of BMSCs cultured for 24 hours in neurobasal medium. During the process, we further identified whether PI3K/AKT signaling pathway is involved through the adjunction of LY294002 (a specific phosphatidylinositide-3-kinase (PI3K) inhibitor). Two hours later, the expression of pAKT (phosphorylated AKT) and AKT were analyzed by Western blotting. The length of axons, the expression of GAP-43 and the survival of neurons were measured at 48 hours. RESULTS: Both BMSCs and CM from BMSCs inreased the axonal length and GAP-43 expression in OGD-injured cortical neurons. There was no difference between the effects of BMSCs of 5×10(5)/ml and of 5×10(3)/ml on axonal outgrowth. Expression of pAKT enhanced significantly at 2 hours and the neuron survival increased at 48 hours after the injured neurons cultured with the CM, respectively. These effects of CM were prevented by inhibitor LY294002. CONCLUSIONS/SIGNIFICANCE: BMSCs promote axonal outgrowth and the survival of neurons against the damage from OGD in vitro by the paracrine effects through PI3K/AKT signaling pathway.

Objective To observe the effects on and the possible mechanism of early exercise training underlying the mobilization of circulating endothelial progenitor cells in patients with acute ischemic stroke.Methods One hundred and twenty patients with acute ischemic stroke were randomized into two groups:an early exercise group (treated with exercise training,n =60) and a control group(no exercise training,n =60).Meanwhile,each group was divided into two different age groups (50-68 years group of 32 cases,＞ 68 years group of 28 cases in exercise group;50-68 years group of 29 cases,＞ 68 years of 31 cases in control group).The amount of circulating endothelial progenitor cells in peripheral blood was accounted by flow cytometry (FCM),while the level of vascular endothelial cell growth factor (VEGF) in blood serum was examined by enzyme-linked immunoassay (ELISA).National Institutes of Health Stroke Scale (NIHSS),Fugl-Meyer Assessment (FMA) and modified Barthel index (MBI) were used to evaluate the patients at 1st day and 14th day after exercise.Results The amount of circulating progenitor cells after 14 days of exercise training in exercise group (from 27.93 ± 6.08/ml to 457.49 ± 73.02/ml)is higher than in control group(from 28.29 ± 5.93/ml to 81.87 ± 9.92/ml) (P ＜ 0.01).Compared with the control group,the level of VEGF at 14th day of exercise group is significantly higher (P ＜ 0.01).The score of NIHSS,FMA,MBI were not significantly different between exercise group and control group (P ＜ 0.01).However,the score of NIHSS was decrease in both exercise group and control group after treatment.Furthermore,the amount of circulating progenitor cells was not significantly different between the age groups either in exercise group or control group (P ＞ 0.05).Conclusion Early Exercise training may promote the mobilization of the circulating progenitor cells,which might be related to the increase of VEGF.The mobilization of the EPCs has no effect on the early neurological function after acute ischemic stroke.Age is not associated with the amount of circulating endothelial progenitor cells.

AIM:To investigate the effects of adipose-derived stem cell (ADSC) transplanting on the outgrowth of neuronal axons and the expressions of GFAP, Neuritin, NF-200 in the brain post focal cerebral ischemia in rats.METHODS:54 male adult Sprague-Dawley rats were randomly divided into 3 groups: sham-operated group, middle cerebral artery occlusion (MCAO) group and MCAO+ADSC-treated group (n=18 in each group). A permenant focal cerebal ischemia model was established using modified Longa's method ADSC was labeled by DAPI before the transplantation. One day after MCAO, 30 μL of cell suspension containing 1×10(6); cells were injected into the lateral ventricle of MCAO+ADSC-treated group. At 7 d, 14 d and 28 d after MCAO, the expressions of GFAP, Neuritin and NF-200 were detected in ischemic region by Western blot and Immunofluorescence analysis.RESULTS:DAPI staining positive cells were observed around the cerebral infarcted area in the ADSC group. The expressions of Neuritin, NF200 were higher, but GFAP was lower than that of the MCAO group at 7 d, 14 d and 28 d (P<0.05).CONCLUSION:The transplantation of ADSC can induce regeneration and repairment of impaired neuronal axons in rat brain after cerebral ischemia, partly by inhibiting the expression of GFAP and enhancing the expressions of Neuritin, NF-200 in the brain.

BACKGROUND:This study was performed to determine whether injury induced by cerebral ischemia could be further improved by transplantation with bone marrow-derived mesenchymal stem cells (MSCs) modified by Survivin (SVV).METHODS:MSCs derived from bone marrow of male Sprague-Dawley rats were infected by the self-inactive lentiviral vector GCFU carrying green fluorescent protein (GFP) gene and SVV recombinant vector (GCFU-SVV). In vitro, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected in infected MSCs supernatants under hypoxic conditions by ELSIA. In vivo, experiments consisted of three groups, one receiving intravenous injection of 500 μl of phosphate-buffered saline (PBS) without cells (control group) and two groups administered the same volume solution with either three million GFP-MSCs (group GFP) or SVV/GFP-MSCs (group SVV). All animals were submitted to 2-hour middle cerebral artery occlusion (MCAO) and then reperfusion. Differentiation and survival of the transplanted MSCs were determined by confocal microscope. Western blot was used to detect the expression of VEGF and bFGF in ischemic tissue. A 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to assess the infarct volume. Evaluation of neurological function was performed using a modified Neurological Severity Score (mNSS).RESULTS:In vitro, modification with SVV further increased secretion of VEGF and bFGF under hypoxic condition. In vivo, only very few transplantated cells co-expressed GFP and NeuN. The survival transplanted cells in the group SVV was 1.3-fold at 4 days after transplantation and 3.4-fold higher at 14 days after transplantation, respectively, when compared with group GFP. Expression of VEGF and bFGF in the ischemic tissue were further up-regulated by modification with SVV. Moreover, modification with SVV further reduced the cerebral infarct volume by 5.2% at 4 days after stroke and improved post-stroke neurological function at 14 days after transplantation.CONCLUSION:Modification with SVV could further enhance the therapeutic effects of MSCs possibly through improving the MSCs survival capacity and up-regulating the expression of protective cytokines in the ischemic tissue.

OBJECTIVE To investigate the effects of the transplantation of adipose-derived stem cells (ADSC) on the expression of Notch1-Dll4 signaling pathway in brains of rats with focal cerebral ischemia. METHODS Sixty-five male adult Sprague-Dawley rats were randomly divided into 4 groups: sham-operated group, MCAO (occlusion of middle cerebral artery) group, ADSC-treated group and ADSC & DAPT-treated group. A permanent model of focal cerebral ischemia was established by modified Zea-Longa's method. At 24 hours post-MCAO, 1×10(6) DAPT-labeled ADSC were injected into the lateral ventricle of rats in the ADSC-treated group and the same dose of ADSC with DAPT (γ secretase inhibitor, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester) to the rats in the ADSC & DAPT-treated group. Rats are sacrificed at 4, 7, 14 and 28 d post-MCAO. The amount of microvessels was quantified. And the levels of Notch1, Dll4 and Hes1 were detected by Western blot and immunohistochemistry. RESULTS The density of microvessels significantly increased in the ADSC group (13.93 ± 0.50, 17.90 ± 0.62, 20.78 ± 0.80, 17.28 ± 1.65) versus the MCAO group (7.03 ± 0.22, 10.83 ± 0.63, 16.35 ± 0.54, 13.80 ± 2.38) (P < 0.05) and the ADSC + DAPT group (5.73 ± 0.30, 7.58 ± 0.52, 7.65 ± 0.45, 6.48 ± 1.47) (P < 0.05). And compared with the MCAO group (1.29 ± 0.07, 2.13 ± 0.21, 1.92 ± 0.03) and the ADSC + DAPT group (1.162 ± 0.099, 1.684 ± 0.180, 1.041 ± 0.040), the expressions of Notch1, Dll4 and Hes1 proteins were significantly up-regulated at 14d in the ADSC group (2.52 ± 0.22, 4.52 ± 0.36, 2.62 ± 0.05) (P < 0.05). CONCLUSION The transplantation of ADSC can improve angiogenesis by up-regulating the post-MCAO expression of Notch1-Dll4 signaling pathway in rats.

We have critically examined the kinetics of latex film formation using an atomic force microscope to obtain corrugation height data as a function of time, temperature, molecular weight, particle size, etc. The results show that the film forming process obeys viscoelastic time/temperature superposition principles, thus indicating a direct relationship between the kinetics of film formation and rheological properties. Film formation kinetics are examined under 'wet' and 'dry' conditions, with film formation occurring almost ten-times faster under wet conditions than dry. This proves for the latex system examined that capillary pressure from the water meniscus is the dominant driving stress for film formation. Past theories for latex film formation are reviewed, and problems and deficiencies are noted. A new theory for film formation from a dry latex system is presented, which is based on the use of the Boltzmann Superposition Principle to relate the changing stress and strain fields as the latex particles deform. The predictions of theory and the experimental data show excellent agreement over nearly four decades of time.

In this second paper of a series dealing with the film-forming behavior of latex systems, we show the relationship between the kinetics of film formation and rheological properties. The kinetics of film formation were followed using atomic force microscopy (AFM), with results that showed the kinetics obeyed time/temperature superposition principles, with the same time/temperature shifts used to superimpose rheological data. This demonstrates a direct relationship between film formation kinetics and rheological properties. A new theory based upon these observations is presented, in which the Boltzmann superposition principle and a time-dependent compliance function J(t) are used to relate the time-dependent biaxial strain psi(t) to the time-dependent driving stress sigma(t). The compliance function J(t) of the latex polymer was obtained by transformation of the master stress relaxation function G(t), which in turn was obtained from time/temperature superposition of experimental stress relaxation data. A comparison of theoretical predictions and experimental data for the kinetics of film formation shows good agreement over the 4 decades of time followed experimentally. The agreement is believed to be within the accuracy of the transformation of G(t) to J(t).

We discuss mechanisms that have been proposed for film formation from latex systems and point out that major problems exist, in that the relative role played by the water/air, the polymer/air, and the polymerwater interfacial tensions in promoting film formation has not been established. Even the relative role played by ''plasticization'' of latex polymers by water has remained as an unanswered question. In order to clarify this problem, we have investigated the rate of film formation of ''wet'' and ''dry'' latex systems by atomic force microscopy. The role of the water surface tension (in creating a ''capillary pressure'') was clearly revealed by forming a ''wet'' latex system through condensation of water into the interstitial space of initially dry latex particles. Poly(iso-butyl methacrylate) (PiBMA) was used as the model latex because of its appropriate glass transition temperature, T-g similar to 65 degrees C, and its hydrophobic character. The rate of film formation (at 70 degrees C) was found to be approximately 10-times faster under ''wet'' conditions than when ''dry''. Separate experiments showed that T-g of PiBMA was unaffected by water, and hence plasticization was not a factor in the enhanced rate. These results clearly show in this system that the dominant factor in promoting film formation was the water surface tension and resulting negative capillary pressure. Furthermore, it is shown that the capillary pressure in wet systems can be of sufficient magnitude to explain the observed deformation of the latex particles at 50 degrees C, i.e., 15 degrees C below T-g. Capillary pressures and forces increase with decreasing amounts of water in the interstitial regions of spherical particles, and capillary pressures can reach very high values with seemingly insignificant amounts of water. The equilibrium between the amount of interstitial water and the relative humidity of the atmospheric water is shown, and it indicates that even with low relative humidities the capillary pressures can still be quite large. We maintain that capillary pressure typically is the dominant driving ''force'' for film formation. These results are in contrast to the conclusions of others.

We raise a question concerning the ability of the atomic force microscope (AFM) to image neighboring atoms of condensed structures. Atomic-scale images produced by the AFM typically show features which do not correspond to the presumed atomic-scale structure; i.e., the symmetry and/or the spacing between ''atoms'' in the image is incorrect. We then discuss the nature and interpretation of atomic-scale imaging by the AFM.