Human brain imaging of nicotinic acetylcholine α4β2* receptors using [18F]Nifene: Selectivity,functional activity,toxicity, aging effects,gender effects,and extrathalamic pathways

Nicotinic acetylcholinergic receptors (nAChR's) have been implicated in several brain disorders, including addiction, Parkinson's disease, Alzheimer's disease and schizophrenia. Here we report in vitro selectivity and functional properties, toxicity in rats, in vivo evaluation in humans, and comparison across species of [¹⁸F]Nifene, a fast acting PET imaging agent for α4β2* nAChRs. Nifene had subnanomolar affinities for hα2β2 (0.34 nM), hα3β2 (0.80 nM) and hα4β2 (0.83 nM) nAChR but weaker (27–219 nM) for hβ4 nAChR subtypes and 169 nM for hα7 nAChR. In functional assays, Nifene (100 μM) exhibited 14% agonist and >50% antagonist characteristics. In 14‐day acute toxicity in rats, the maximum tolerated dose (MTD) and the no observed adverse effect level (NOAEL) were estimated to exceed 40 μg/kg/day (278 μg/m²/day). In human PET studies, [¹⁸F]Nifene (185 MBq; <0.10 μg) was well tolerated with no adverse effects. Distribution volume ratios (DVR) of [¹⁸F]Nifene in white matter thalamic radiations were ～1.6 (anterior) and ～1.5 (superior longitudinal fasciculus). Habenula known to contain α3β2 nAChR exhibited low levels of [¹⁸F]Nifene binding while the red nucleus with α2β2 nAChR had DVR ～1.6–1.7. Females had higher [¹⁸F]Nifene binding in all brain regions, with thalamus showing >15% than males. No significant aging effect was observed in [¹⁸F]Nifene binding over 5 decades. In all species (mice, rats, monkeys, and humans) thalamus showed highest [¹⁸F]Nifene binding with reference region ratios >2 compared to extrathalamic regions. Our findings suggest that [¹⁸F]Nifene PET may be used to study α4β2* nAChRs in various CNS disorders and for translational research.     

Association of serum albumin to globulin ratio with outcomes in acute ischemic stroke

Background

Serum albumin to globulin ratio (A/G) has been widely used as a representative biomarker for assessing inflammation and nutrition status. However, in patients with acute ischemic stroke (AIS), the predictive value of serum A/G has rarely been reported. We aimed to evaluate whether serum A/G is associated with prognosis in stroke.

Methods

We analyzed data from the Third China National Stroke Registry. The patients were categorized into quartile groups according to the serum A/G at admission. Clinical outcomes included poor functional outcomes (modified Rankin Scale [mRS] score of 3–6 or 2–6) and all-cause mortality at 3 months and1 year. Multivariable logistic regressions and Cox proportional hazards regressions were used to evaluate the association of serum A/G with the risk of poor functional outcomes and all-cause mortality.

Results

A total of 11, 298 patients were included in this study. After adjustment for confounding factors, patients in the highest serum A/G quartile had a lower proportion of mRS score 2–6 (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.76–1.00) and mRS score 3–6 (OR, 0.87; 95% CI, 0.73–1.03) at 3 months follow-up. At 1 year follow-up, there was a significant association between higher serum A/G and mRS score 3–6 (OR, 0.68; 95% CI, 0.57–0.81). We also found that the highest serum A/G was related to decreased risk of all-cause mortality (hazard ratio [HR], 0.58; 95% CI, 0.36–0.94) at 3 months follow-up. Similar results were found at 1-year follow-up.

Conclusions

Lower serum A/G levels were associated with poor functional outcomes and all-cause mortality at 3 months and 1-year follow-up in patients with acute ischemic stroke.     

COVID-19 knowledge,risk perception,and information sources among Chinese population

BACKGROUNDMeasures for effective control of the coronavirus disease 2019 (COVID-19) pandemic include identifying the causal organisms, applying appropriate therapies, and developing vaccines, as well as improving understanding among the general public.AIMTo evaluate the knowledge, awareness, perception, and response of the general public to COVID-19 in China.METHODSA detailed questionnaire comprising 47 questions designed in both English and Chinese was developed. The survey was conducted via WeChat, a multipurpose messaging, social media, and mobile payment app that is widely used by the Chinese population. In total, 1006 participants responded, and most of them were from different provinces of mainland China.RESULTSOverall, this comprehensive survey revealed that the general public in China is highly aware of the basic information concerning COVID-19 and its precautions. Interestingly, more respondents (99.3%) were aware of the term severe acute respiratory syndrome (SARS) than COVID-19 (97.2%) and Middle East respiratory syndrome (MERS) (73.4%). Among them, 2.4%, 1.6%, and 0.9% said that they or their family members or friends were affected by COVID-19, SARS, and MERS, respectively. The majority of the respondents (91.2%) indicated that knowledge about COVID-19 was received mainly from WeChat, followed by TV (89%), friends (76.1%), and QQ (a Chinese instant messaging software service) (57.7%).CONCLUSIONThe general public in China is highly aware of COVID-19 and the necessary precautions. Unexpectedly, 2.8% of the participants were unaware of the current epidemic. The remaining information gaps highlight the necessity of further enhancing awareness and preparedness.     

Mycobacterium tuberculosis DNA gyrase: interaction with quinolones and correlation with antimycobacterial drug activity

Genome studies suggest that DNA gyrase is the sole type II topoisomerase and likely the unique target of quinolones in Mycobacterium tuberculosis. Despite the emerging importance of quinolones in the treatment of mycobacterial disease, the slow growth and high pathogenicity of M. tuberculosis have precluded direct purification of its gyrase and detailed analysis of quinolone action. To address these issues, we separately overexpressed the M. tuberculosis DNA gyrase GyrA and GyrB subunits as His-tagged proteins in Escherichia coli from pET plasmids carrying gyrA and gyrB genes. The soluble 97-kDa GyrA and 72-kDa GyrB subunits were purified by nickel chelate chromatography and shown to reconstitute an ATP-dependent DNA supercoiling activity. The drug concentration that inhibited DNA supercoiling by 50% (IC(50)) was measured for 22 different quinolones, and values ranged from 2 to 3 microg/ml (sparfloxacin, sitafloxacin, clinafloxacin, and gatifloxacin) to >1,000 microg/ml (pipemidic acid and nalidixic acid). By comparison, MICs measured against M. tuberculosis ranged from 0.12 microg/ml (for gatifloxacin) to 128 microg/ml (both pipemidic acid and nalidixic acid) and correlated well with the gyrase IC(50)s (R(2) = 0.9). Quinolones promoted gyrase-mediated cleavage of plasmid pBR322 DNA due to stabilization of the cleavage complex, which is thought to be the lethal lesion. Surprisingly, the measured concentrations of drug inducing 50% plasmid linearization correlated less well with the MICs (R(2) = 0.7). These findings suggest that the DNA supercoiling inhibition assay may be a useful screening test in identifying quinolones with promising activity against M. tuberculosis. The quinolone structure-activity relationship demonstrated here shows that C-8, the C-7 ring, the C-6 fluorine, and the N-1 cyclopropyl substituents are desirable structural features in targeting M. tuberculosis gyrase.     

Effect of morphine on deep dorsal horn projection neurons depends on spinal GABAergic and glycinergic tone: implications for reduced opioid effect in neuropathic pain

The mu opioid agonist morphine has distinct effects on spinal dorsal horn neurons in the superficial and deep laminae. However, it is not clear if the inhibitory effect of morphine on dorsal horn projection neurons is secondary to its potentiating effect on inhibitory interneurons. In this study, we tested the hypothesis that removal of GABAergic and glycinergic inhibitory inputs attenuates the effect of morphine on dorsal horn projection neurons and the reduced spinal GABAergic tone contributes to attenuated morphine effect in neuropathic pain. Single-unit activity of deep dorsal horn projection neurons was recorded in anesthetized normal/sham controls and L(5) and L(6) spinal nerve-ligated rats. Spinal application of 10 microM morphine significantly inhibited the evoked responses of dorsal horn neurons in both normal/sham controls, and this effect was abolished by the specific mu opioid antagonist. However, the effect of morphine on dorsal horn projection neurons was significantly reduced in nerve-injured rats. Furthermore, topical application of the GABA(A) receptor antagonist bicuculline (20 microM) almost abolished the effect of morphine in normal/sham control rats but did not significantly attenuate the morphine effect in nerve-injured rats. On the other hand, the glycine receptor antagonist strychnine (4 microM) significantly decreased the effect of morphine in both nerve-injured and control animals. These data suggest that the inhibitory effect of opioids on dorsal horn projection neurons depends on GABAergic and glycinergic inputs. Furthermore, reduced GABAergic tone probably contributes to diminished analgesic effect of opioids in neuropathic pain.     

手术器械基础包优化配置与成本控制

[目的]在充分满足手术需求的前提下优化配置手术器械基础包,控制成本支出。[方法]观察我院需要手术器械基础包的手术1 000例,统计、分析各种器械在术中的使用数量,然后删减包内器械,得出优化器械基础包;将常见手术200例随机分为试验组和对照组,试验组使用优化配置后的手术器械基础包,对照组使用传统的手术器械基础包,比较两组手术医生对手术器械的供求满意度、手术时间及所用基础包的器械购置成本、再生处理成本。[结果]两组器械基础包在手术时间和医生满意度方面比较差异有统计学意义（P〈0.05）,优化配置后的手术器械基础包器械配置成本降低了56.20%,再生处理成本较优化前明显降低（P〈0.05）。[结论]对手术器械基础包进行优化配置,能在满足医生对手术器械需求的同时,降低成本支出。     

蛛网膜下腔出血临床与数字减影血管造影术分析(附23例报告)

目的 分析自发性蛛网膜下腔出血（ＳＡＨ）的临床与数字减影血管造影术（ＤＳＡ）的特点。方法 回顾性分析２３例ＳＡＨ患者症状、病因、预后及ＤＳＡ检查。结果 头痛、呕吐、脑膜刺激征阳性是ＳＡＨ主要症状。经ＤＳＡ发现,２３种中２０例有脑动脉瘤,２例为多发;共计２２个动脉瘤,２１个位于Ｗｉｌｌｉｓ环,１４个位于前交通动脉。９例行手术治疗,５例行介入治疗,７例内科保守治疗,除２例死亡外,２１例均痊愈。接受ＣＳ     

Cardiomyocytes can be generated from marrow stromal cells in vitro

We have isolated a cardiomyogenic cell line (CMG) from murine bone marrow stromal cells. Stromal cells were immortalized, treated with 5-azacytidine, and spontaneously beating cells were repeatedly screened. The cells showed a fibroblast-like morphology, but the morphology changed after 5-azacytidine treatment in approximately 30% of the cells; they connected with adjoining cells after one week, formed myotube-like structures, began spontaneously beating after two weeks, and beat synchronously after three weeks. They expressed atrial natriuretic peptide and brain natriuretic peptide and were stained with anti-myosin, anti-desmin, and anti-actinin antibodies. Electron microscopy revealed a cardiomyocyte-like ultrastructure, including typical sarcomeres, a centrally positioned nucleus, and atrial granules. These cells had several types of action potentials, such as sinus node-like and ventricular cell-like action potentials. All cells had a long action potential duration or plateau, a relatively shallow resting membrane potential, and a pacemaker-like late diastolic slow depolarization. Analysis of the isoform of contractile protein genes, such as myosin heavy chain, myosin light chain, and alpha-actin, indicated that their muscle phenotype was similar to that of fetal ventricular cardiomyocytes. These cells expressed Nkx2.5/Csx, GATA4, TEF-1, and MEF-2C mRNA before 5-azacytidine treatment and expressed MEF-2A and MEF-2D after treatment. This new cell line provides a powerful model for the study of cardiomyocyte differentiation.