Overexpression of C-terminal fragment of glutamate receptor 6 prevents neuronal injury in kainate-induced seizure via disassembly of GluR6-PSD95-MLK3 signaling module

Our previous study showed that when glutamate receptor （GluR）6 C terminus-containing peptide conjugated with the human immunodeficiency virus Tat protein （GluR6）-9c is delivered into hippocampal neurons in a brain ischemic model, the activation of mixed lineage kinase 3 （MLK3） and c-Jun NH2-terminal kinase （JNK） is inhibited via GluR6-postsynaptic density protein 95 （PSD95）. In the present study, we investigated whether the recombinant adenovirus （Ad） carrying GluR6c could suppress the assembly of the GluR6-PSD95-MLK3 signaling module and decrease neuronal cell death induced by kainate in hippocampal CA1 subregion. A seizure model in Sprague-Dawley rats was induced by intraperitoneal injections of kainate. The effect of Ad- Glur6-9c on the phosphorylation of INK, MLK3 and mitogen-activated ldnase kinase 7 （MKK7） was observed with western immunoblots and immunohistochemistry. Our findings revealed that overexpression of GluR6c inhibited the interaction of GluR6 with PSD95 and prevented the kainate-induced activation of INK, MLK3 and MKK7. Furthermore, kainate-mediated neuronal cell death was significantly suppressed by GluR6c. Taken together, GluR6 may play a pivotal role in neuronal cell death.     

Evaluation of N95 respirators,modified snorkel masks and low-cost powered air-purifying respirators: a prospective observational cohort study in healthcare workers

Disposable N95 respirator masks are the current standard for healthcare worker respiratory protection in the COVID-19 pandemic. In addition to shortages, qualitative fit testing can have low sensitivity for detecting poor fit, leading to inconsistent protection. Multiple groups have developed alternative solutions such as modified snorkel masks to overcome these limitations, but validation of these solutions has been lacking. We sought to determine if N95s and snorkel masks with attached high-efficiency filters provide consistent protection levels in healthcare workers and if the addition of positive pressure via an inexpensive powered-air purifying respirator to the snorkel mask would provide enhanced protection. Fifty-one healthcare workers who were qualitatively fitted with N95 masks underwent quantitative mask fit testing according to a simulated workplace exercise protocol. N95, snorkel masks with high-efficiency filters and snorkel masks with powered-air purifying respirators were tested. Respiratory filtration ratios were collected for each step and averaged to obtain an overall workplace protocol fit factor. Failure was defined as either an individual filtration ratio or an overall fit factor below 100. N95s and snorkel masks with high-efficiency filters failed one or more testing steps in 59% and 20% of participants, respectively, and 24% and 12% failed overall fit factors, respectively. The snorkel masks with powered-air purifying respirators had zero individual or overall failures. N95 and snorkel masks with high-efficiency filter respirators were found to provide inconsistent respiratory protection in healthcare workers.     

Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum (PCC) was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits (2.5–3.0 kg) were precontracted with phenylephrine (Phe, 10 µmol l⁻¹) and then treated with various concentrations of Cuscuta chinensis extract (1, 2, 3, 4 and 5 mg ml⁻¹). The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay (RIA). The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase (NOS) inhibitor (Nω nitro-L-arginine-methyl ester, L-NAME), a guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ), or a protein kinase A inhibitor (KT 5720) did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction (ED), which does not completely respond to sildenafil citrate.     

衰老对大鼠阴茎组织NO-cGMP通路及端粒酶活性的影响研究

目的探讨衰老对大鼠阴茎组织结构、NO(nitric oxide)-cGMP(cvclic Guanosine Monophosphate)通路及端粒酶活性的影响作用。方法本课题以不同月龄大鼠阴茎组织及培养的平滑肌细胞为研究对象,检测不同月龄大鼠阴茎组织中NO量、NOS(Nitric Oxide Synthase)活性、cGMP量、端粒酶活性及海绵体结构的变化,并比较大鼠、人阴茎组织及大鼠原代海绵体平滑肌细胞的端粒酶活性。结果(1)大鼠阴茎组织中NO量、NOS活性均先升高后降低,各月龄组间有显著差异。阴茎组织cGMP含量逐渐降低,各月龄组间差别显著；(2)随龄增加,平滑肌纤维逐渐减少,胶原纤维增多,粗大成团,窦状隙变少、变窄：(3)大鼠阴茎组织端粒酶活性以2月龄活性最高,随龄增加逐渐下降。人阴茎组织中无端粒酶活性。结论(1)衰老对大鼠阴茎组织结构、NO．cGMP通路及端粒酶活性有显著影响,提示衰老与ED关系密切；(2)大鼠阴茎组织有端粒酶活性,可作为研究细胞衰老与ED关系有关端粒酶的模型。     

西地那非治疗勃起功能障碍的有效性:中文文献的meta分析

目的评价西地那非治疗ED的有效性。方法通过中国生物医学文摘光盘(CBMdisc 2004新版)和清华同方数据库中CHKD期刊全文库检索公开发表的中文文献。凡摘要或方法中出现随机对照字样,无论有无盲法均予纳入。对纳入的试验设计特征用Jadad计分评价。以IIEF中Q3和Q4评分及IIEF总评分为疗效指标,采用RevMan4．1软件进行Meta分析。结果共有9个随机对照试验被纳入。其中6个为Jadad计分3分以上高质量试验。5个试验的IIEF Q3和Q4评分meta分析,OR=8．83,95％CI为(6．67,11．69),P<0．0001。4个高质量试验的IIEF总评分meta分析OR=13．76,95％CI为(9．50,19．92),P<0．0001。显示西地那非能够显著提高ED患者的疗效指标。结论西地那非能有效改善男性勃起功能,是一种有效治疗ED的口服药物。     

A pre-operative clinical scoring system to distinguish perforation risk with pediatric appendicitis

Importance

Appendicitis is a common, potentially serious pediatric disease. An important factor in determining management strategy [whether/when to perform appendectomy, duration of antibiotic therapy/hospitalization, etc.] and predicting outcome is distinguishing whether perforation is present.

Raising suspicion of maltreatment from burns: Derivation and validation of the BuRN-Tool

Background

10–25% of childhood burns arise from maltreatment.

高原健康人缺氧诱导因子-1α、诱导性一氧化氮合酶和一氧化氮的海拔性变化与红细胞变形能力的关系研究

目的：观察缺氧诱导因子-1α、诱导性一氧化氮合酶、一氧化氮和红细胞滤过指数在不同海拔的变化,探讨缺氧诱导因子-1α、诱导性一氧化氮合酶和一氧化氮的海拔性变化对红细胞变形能力的影响。方法：对不同海拔高度（西宁2 260m A组、刚察县3 300m B组、甘德县4 800m C组）320例健康人检测了缺氧诱导因子-1α（HIF-1α）、诱导性一氧化氮合酶（i NOS）、一氧化氮（NO）和红细胞滤过指数（EFI）。结果：随着海拔的升高,健康人HIF-1α水平和EFI上升,而i NOS和NO随之降低;甘德组HIF-1α水平（7.65±1.36）μg/L明显高于刚察组（5.39±1.02）μg/L和西宁组（4.18±1.14）μg/L（均P〈0.01）,刚察组HIF-1α水平明显高于西宁组;甘德组血清i NOS和NO（5.86±1.43）μmol/L、（38.53±4.23）μmol/L明显低于刚察组（9.44±2.13）μmol/L、（47.85±3.77）μmol/L和西宁组（12.23±2.07）μmol/L、（59.23±4.01）μmol/L（均P〈0.01）,同时刚察组i NOS和NO水平明显低于西宁组（P〈0.01）;EFI随着海拔升高而增加[西宁组：（4.67±0.49）μmol/L、刚察组：（7.05±1.51）μmol/L、甘德组：（11.45±1.78）μmol/L],各组比较有明显差异（P〈0.01）;相关分析表明：EFI与HIF-1α水平呈正相关（P〈0.01）;而与i NOS和NO呈负相关。结论：HIF-1α、i NOS和NO海拔差异性的形成在红细胞变形能力异常的病理生理机制中发挥着重要作用,而随海拔高度升高机体i NOS和NO水平的生物学特性进一步降低是导致海拔差异健康人红细胞流变形异常加重的中心环节。     

Molecular interactions of the plasma membrane calcium ATPase 2 at pre- and post-synaptic sites in rat cerebellum

The plasma membrane calcium extrusion mechanism, PMCA (plasma membrane calcium ATPase) isoform 2 is richly expressed in the brain and particularly the cerebellum. Whilst PMCA2 is known to interact with a variety of proteins to participate in important signalling events [Strehler EE, Filoteo AG, Penniston JT, Caride AJ (2007) Plasma-membrane Ca(2+) pumps: structural diversity as the basis for functional versatility. Biochem Soc Trans 35 (Pt 5):919–922], its molecular interactions in brain synapse tissue are not well understood. An initial proteomics screen and a biochemical fractionation approach identified PMCA2 and potential partners at both pre- and post-synaptic sites in synapse-enriched brain tissue from rat. Reciprocal immunoprecipitation and GST pull-down approaches confirmed that PMCA2 interacts with the post-synaptic proteins PSD95 and the NMDA glutamate receptor subunits NR1 and NR2a, via its C-terminal PDZ (PSD95/Dlg/ZO-1) binding domain. Since PSD95 is a well-known partner for the NMDA receptor this raises the exciting possibility that all three interactions occur within the same post-synaptic signalling complex. At the pre-synapse, where PMCA2 was present in the pre-synapse web, reciprocal immunoprecipitation and GST pull-down approaches identified the pre-synaptic membrane protein syntaxin-1A, a member of the SNARE complex, as a potential partner for PMCA2. Both PSD95–PMCA2 and syntaxin-1A–PMCA2 interactions were also detected in the molecular and granule cell layers of rat cerebellar sagittal slices by immunohistochemistry. These specific molecular interactions at cerebellar synapses may allow PMCA2 to closely control local calcium dynamics as part of pre- and post-synaptic signalling complexes.