Objective:Using T2-weighted imaging(T2WI),diffusion-weighted imaging(DWI),pulsed gradient spin echo(PGSE)multiparametric magnetic resonance imaging combined with various histopathological techniques to observe the effects of reperfusion after different times of cerebral ischemia(CIRI)on the cytotoxic edema of brain tis-sues in rats.This provides a solid foundation for the establishment of ischemic stroke models and clinical diagnosis and treatment.Methods:Healthy adult male Sprague Dawley rats were randomly allocated to four groups:the sham-opera-ted(Sham)group,the ischaemia 60 min reperfusion(IR-60 min)group,the IR-120 min group,and the IR-180 min group.CIRI rat model was prepared by modified Zea Longa method.Laser doppler flowmetry combined with hematoxy-lin-eosin(HE)staining was employed to identify the model.Multiparametric magnetic resonance imaging,combined with water content of brain,immunofluorescence staining of aquaporin-4(AQP4),and Western Blot were performed to observe cytotoxic edema of brain tissues and tumour necrosis factor alpha(TNF-α),interleukin 1β(IL-1β)in brain tissue of rats in each group.Results:HE staining and determination of brain tissue water content prove that as ischemia time prolongs,the degree of cerebral cortex edema on the ischemic side increases.The T2WI results showed that the injury in the IR-60 min group began to affect the cerebral cortex,the injury in the IR-120 min group had completely affected the cerebral cortex,and the injury in the IR-180 min group was the most severe(P＜0.05),with a significant shift of the midline of the brain towards the opposite side.The relative apparent diffusion coefficient and water exchange time of the cerebral cortex on the ischemic side of the rats were found to be significantly lower than those of the sham group,with an declining trend(P＜0.05).Additionally,the values of cell membrane permeability of the cerebral cor-tex on the ischemic side of the rats were observed to be significantly higher than those of the sham group in all groups(P＜0.05).The expression of AQP4,IL-1 β and TNF-α in the cerebral cortex of ischemic side was significantly higher than that in the sham group,and showed an upward trend(P＜0.05).Conclusion:Reperfusion following 60,120 and,180 minutes of middle cerebral artery ischemia in rats can result in brain damage.Prolongation of ischemia time has been shown to exacerbate the toxic edema of brain cells and brain damage.Ischemia of 120 minutes reperfusion has been identified as the optimal modeling time for ischemic stroke.Multiparametric MRI can be utilized to monitor the mi-crostructural changes of brain tissue in rats following CIRI in vivo,providing a foundation for the visualization of early clinical diagnosis and treatment.

Objective:Using T2-weighted imaging(T2WI),diffusion-weighted imaging(DWI),pulsed gradient spin echo(PGSE)multiparametric magnetic resonance imaging combined with various histopathological techniques to observe the effects of reperfusion after different times of cerebral ischemia(CIRI)on the cytotoxic edema of brain tis-sues in rats.This provides a solid foundation for the establishment of ischemic stroke models and clinical diagnosis and treatment.Methods:Healthy adult male Sprague Dawley rats were randomly allocated to four groups:the sham-opera-ted(Sham)group,the ischaemia 60 min reperfusion(IR-60 min)group,the IR-120 min group,and the IR-180 min group.CIRI rat model was prepared by modified Zea Longa method.Laser doppler flowmetry combined with hematoxy-lin-eosin(HE)staining was employed to identify the model.Multiparametric magnetic resonance imaging,combined with water content of brain,immunofluorescence staining of aquaporin-4(AQP4),and Western Blot were performed to observe cytotoxic edema of brain tissues and tumour necrosis factor alpha(TNF-α),interleukin 1β(IL-1β)in brain tissue of rats in each group.Results:HE staining and determination of brain tissue water content prove that as ischemia time prolongs,the degree of cerebral cortex edema on the ischemic side increases.The T2WI results showed that the injury in the IR-60 min group began to affect the cerebral cortex,the injury in the IR-120 min group had completely affected the cerebral cortex,and the injury in the IR-180 min group was the most severe(P＜0.05),with a significant shift of the midline of the brain towards the opposite side.The relative apparent diffusion coefficient and water exchange time of the cerebral cortex on the ischemic side of the rats were found to be significantly lower than those of the sham group,with an declining trend(P＜0.05).Additionally,the values of cell membrane permeability of the cerebral cor-tex on the ischemic side of the rats were observed to be significantly higher than those of the sham group in all groups(P＜0.05).The expression of AQP4,IL-1 β and TNF-α in the cerebral cortex of ischemic side was significantly higher than that in the sham group,and showed an upward trend(P＜0.05).Conclusion:Reperfusion following 60,120 and,180 minutes of middle cerebral artery ischemia in rats can result in brain damage.Prolongation of ischemia time has been shown to exacerbate the toxic edema of brain cells and brain damage.Ischemia of 120 minutes reperfusion has been identified as the optimal modeling time for ischemic stroke.Multiparametric MRI can be utilized to monitor the mi-crostructural changes of brain tissue in rats following CIRI in vivo,providing a foundation for the visualization of early clinical diagnosis and treatment.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the outbreak of coronavirus disease 2019 in Wuhan City, China. The SARS-CoV-2 is genetically similar to the coronavirus derived from bat. The SARS-CoV-2, the SARS-CoV and the Middle East respiratory syndrome coronavirus (MERS-CoV) all belong to beta coronavirus. Since the outbreak of the coronavirus disease 2019, effective antiviral drugs have become a hot issue in the world. Very little about SARS-CoV-2 is known and there is no precedent for treatment. The National Health Commission has repeatedly revised the diagnosis and treatment guide for the coronavirus disease 2019. The latest guide is "New Coronary Virus-Infected Pneumonia Diagnosis and Treatment Plan (Seventh Trial Version)"(short for Seventh Version of Diagnosis and Treatment Plan). But the use of antiviral drugs is still on trial and no rigorous clinical trials data is available. Hot anti-SARS-CoV-2 drugs include interferon α, ribavirin, lopinavir/ritonavir, chloroquine phosphate, abidol, as well as hydroxychloroquine sulfate and remdesivir. But the later 2 drugs aren't mentioned in the Seventh Version of Diagnosis and Treatment Plan.
Antiviral Agents ; therapeutic use ; Betacoronavirus ; China ; Coronavirus Infections ; drug therapy ; Humans ; Pandemics ; Pneumonia, Viral ; drug therapy ; Practice Guidelines as Topic

Embryonic stem cell (ESC) is a kind of stem cell with self-renewal capability and developmental luripotency,which is at the early stage of embryonic development,and it is the original cell of various kinds of tissue and organ.Under certain conditions,ESCs can maintain an undifferentiated state,long-term surviving and infinite breeding state in vitro.The research of tberapeutic effect of ESCs in animal disease model,especially in ouse,has made great progress.On the basis of this research,researchers attempt to use ESCs for the clinical therapy of various diseases,and investigate the feasibility and security of this kind of therapy.Currently ESCs have been used in the therapy of diabetes mellitus,Parkinson's disease and cardiovascular injury.Even though many problems of technique and ethics should be done,we believe that ESC therapy will be a promising method and used in linical practice if we make clear the mechanism of ESC directional differentiation,establish an optimal culture system,and solve the problem of oncogenicity.