聚(2-乙基-2-噁唑啉)-胆固醇碳酸甲酯修饰的多西紫杉醇pH-敏感胶束的构建与性质考察

目的 利用聚(2-乙基-2-噁唑啉)-胆固醇碳酸甲酯[poly(2-ethyl-2-oxazoline)-cholesteryl methyl carbonate,PEOz-CHMC,简称PC]构建多西紫杉醇(docetaxel,DOC)纳米胶束,并对其进行性质考察。方法 利用芘荧光探针法测定PC的临界胶束浓度。利用薄膜分散法制备DOC-PC胶束(DOC-PC micelles,DOC-M),对DOC-M的粒径、形态、包封率等进行表征。采用透析法考察DOC-M的药物释放,并模拟肿瘤微环境考察DOC-M的稳定性和pH敏感性。通过MTT法评价DOC-M对体外HeLa细胞的抑制作用。利用流式细胞仪定量观察胶束对HeLa细胞的摄取情况。结果 PC的临界胶束质量浓度为9.26 μg·mL^-1(4.63×10^-6mol·L^-1)。DOC-M的粒径小于130 nm,外观呈类球形,分布均匀,Zeta电位为(-7.32±0.98)mV。X-射线粉末衍射(XRD)和红外光谱(IR)结果表明,DOC被成功包封于胶束中,DOC-M的包封率为(80.55±2.44)%。体外药物释放和胎牛血清稳定性结果实验表明,DOC-M的pH敏感性和稳定性良好。细胞抑制实验结果表明,在微酸条件下DOC-M的细胞抑制作用更强。细胞摄取实验分析,DOC-M具有较低的毒性,显著地促进药物的细胞摄取。结论 DOC-M表现出良好的稳定性和pH敏感性,以及较低毒性和较好的载药能力,有望成为药物递送的良好载体。     

Crystal structure and functional mapping of human ASMT,the last enzyme of the melatonin synthesis pathway

Abstract: Melatonin is a synchronizer of many physiological processes. Abnormal melatonin signaling is associated with human disorders related to sleep, metabolism, and neurodevelopment. Here, we present the X‐ray crystal structure of human N‐acetyl serotonin methyltransferase (ASMT), the last enzyme of the melatonin biosynthesis pathway. The polypeptide chain of ASMT consists of a C‐terminal domain, which is typical of other SAM‐dependent O‐methyltransferases, and an N‐terminal domain, which intertwines several helices with another monomer to form the physiologically active dimer. Using radioenzymology, we analyzed 20 nonsynonymous variants identified through the 1000 genomes project and in patients with neuropsychiatric disorders. We found that the majority of these mutations reduced or abolished ASMT activity including one relatively frequent polymorphism in the Han Chinese population (N17K, rs17149149). Overall, we estimate that the allelic frequency of ASMT deleterious mutations ranges from 0.66% in Europe to 2.97% in Asia. Mapping of the variants on to the 3‐dimensional structure clarifies why some are harmful and provides a structural basis for understanding melatonin deficiency in humans.     

基于UPLC-Q-TOF-MS指纹图谱和分子对接技术筛选藿香正气水抗新冠病毒潜在质量标志物

目的 基于超高效液相色谱-四极杆-飞行时间串联质谱(UPLC-Q-TOF-MS)指纹图谱和分子对接技术,确定藿香正气水(Huoxiang Zhengqi Shui,HZS)抗新型冠状病毒(SARS-CoV-2)的潜在质量标志物(quality markers,Q-Marker)。方法 对27批HZS样品建立UPLC-Q-TOF-MS指纹图谱,结合化学计量学方法,筛选出HZS的差异性成分;以瑞德西韦为阳性对照,将HZS的差异性成分与SARS-CoV-2主蛋白酶(main protease,Mpro)进行分子对接,进一步确定HZS的潜在Q-Marker。结果 通过建立27批HZS样品的UPLC-Q-TOF-MS指纹图谱,标定了27种共有化合物;结合层次聚类分析(hierarchical clustering analysis,HCA)和主成分分析(principal component analysis,PCA),确定了其中14种共有化合物在27批HZS样品中具有较大的差异性,并鉴定出了橙皮苷、氧化前胡素、新比克白芷内脂、甜橙素、甘草酸、3,5,6,7,8,3'',4''-七甲氧基黄酮、桔皮素、欧前胡素、珊瑚菜素9种差异性化合物;9种差异性化合物的分子对接结果显示,橙皮苷、氧化前胡素、新比克白芷内脂、甘草酸、欧前胡素、珊瑚菜素6种化合物能与SARS-CoV-2 Mpro的活性氨基酸结合,具有抑制SARS-CoV-2 Mpro的潜能,可作为HZS的潜在Q-Marker。结论 将UPLC-Q-TOF-MS指纹图谱、化学计量学分析和分子对接技术交叉使用,确定了HZS的潜在Q-Marker,该方法为药物成分鉴定、同一类药物成分差异性分析,及其功效研究方面提供一定参考。     

Disturbance of zinc and glucose homeostasis by methyl tert-butyl ether (MTBE); evidence for type 2 diabetes

1.?The prevalence of diabetes and the other metabolic disorders has noticeably increased worldwide. A causal link between increasing risk of type 2 diabetes and exposure to environmental pollutants has been reported.

2.?We hypothesized that exposure to methyl tert-butyl ether (MTBE), an oxygenate additive to gasoline would hinder zinc and glucose homeostasis in rats.

3.?Male Sprague–Dawley rats received MTBE in drinking water for 90 days. At the end of the treatment, pancreas and blood samples were collected for biochemical and molecular examinations. Expression of four candidate genes, including Insulin1, Insulin2, MT1A, SLC30A8 by Real-Time Quantitative PCR (Q-PCR) as well as biochemical parameters, including fasting blood glucose (FBS), triglycerides (TG), cholesterol (CHO), low-density lipoprotein (LDL), high-density lipoprotein (HDL), copper (Cu²⁺) and calcium (Ca²⁺) levels as well as High-sensitive C-reactive protein were assessed as endpoints.

4.?This study suggested that MTBE exposure can be associated with disruption in zinc homeostasis and glucose tolerance.     

Protein Content and Methyl Donors in Maternal Diet Interact to Influence the Proliferation Rate and Cell Fate of Neural Stem Cells in Rat Hippocampus

Maternal diet during pregnancy and early postnatal life influences the setting up of normal physiological functions in the offspring. Epigenetic mechanisms regulate cell differentiation during embryonic development and may mediate gene/environment interactions. We showed here that high methyl donors associated with normal protein content in maternal diet increased the in vitro proliferation rate of neural stem/progenitor cells isolated from rat E19 fetuses. Gene expression on whole hippocampi at weaning confirmed this effect as evidenced by the higher expression of the Nestin and Igf2 genes, suggesting a higher amount of undifferentiated precursor cells. Additionally, protein restriction reduced the expression of the insulin receptor gene, which is essential to the action of IGFII. Inhibition of DNA methylation in neural stem/progenitor cells in vitro increased the expression of the astrocyte-specific Gfap gene and decreased the expression of the neuron-specific Dcx gene, suggesting an impact on cell differentiation. Our data suggest a complex interaction between methyl donors and protein content in maternal diet that influence the expression of major growth factors and their receptors and therefore impact the proliferation and differentiation capacities of neural stem cells, either through external hormone signals or internal genomic regulation.     

Intrathecal Prednisolone Therapy in Postoperative Arachnoiditis Following Operation of Herniated Disc

Fourteen patients with severe, chronic sciatica operated on repeatedly but without lasting success were treated by two intrathecal injections of methyl prednisolone (40 mg and 80 mg) at an interval of a few days. Significant improvement was obtained with regard to pain in many cases, but as there was no control series it is difficult to assess the results.     

Principles of studying low-level neurotoxic exposures in children: using the Seychelles Child Development Study of methyl mercury as a prototype

Epidemiological studies to determine the impact of low level toxic exposure on child development are important in guiding clinical and public health action. However, carrying out such studies and interpreting their findings presents a number of significant challenges to the investigators. First, they must find a cohort with suitable exposure, select a biomarker that will accurately determine the level of exposure and determine the endpoints that are most likely to detect subtle differences in neurodevelopment. Following that, the logistics of the study must be organised and collaboration established with the local population and health authorities. To accurately interpret the data, they must also accurately determine covariates that impact child development. After the data are collected, interpreting the findings presents a further challenge. Throughout this process, the study must adhere to fundamental epidemiological principles and clearly defined statistical approaches. This paper discusses those principles and uses the Seychelles Child Development Study to show how one epidemiological study addressed them.     

Neurometabolic profiles of the substantia nigra and striatum of MPTP‐intoxicated common marmosets: An in vivo proton MRS study at 9.4 T

Given the strong coupling between the substantia nigra (SN) and striatum (STR) in the early stage of Parkinson's disease (PD), yet only a few studies reported to date that have simultaneously investigated the neurochemistry of these two brain regions in vivo, we performed longitudinal metabolic profiling in the SN and STR of 1‐methyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐intoxicated common marmoset monkey models of PD (n = 10) by using proton MRS (¹H–MRS) at 9.4 T. T₂ relaxometry was also performed in the SN by using MRI. Data were classified into control, MPTP_2weeks, and MPTP_6‐10 weeks groups according to the treatment duration. In the SN, T₂ of the MPTP_6‐10 weeks group was lower than that of the control group (44.33 ± 1.75 versus 47.21 ± 2.47 ms, p < 0.05). The N‐acetylaspartate to total creatine ratio (NAA/tCr) and γ‐aminobutyric acid to tCr ratio (GABA/tCr) of the MPTP_6‐10 weeks group were lower than those of the control group (0.41 ± 0.04 versus 0.54 ± 0.08 (p < 0.01) and 0.19 ± 0.03 versus 0.30 ± 0.09 (p < 0.05), respectively). The glutathione to tCr ratio (GSH/tCr) was correlated with T₂ for the MPTP_6‐10 weeks group (r = 0.83, p = 0.04). In the STR, however, GABA/tCr of the MPTP_6‐10 weeks group was higher than that of the control group (0.25 ± 0.10 versus 0.16 ± 0.05, p < 0.05). These findings may be an in vivo depiction of the altered basal ganglion circuit in PD brain resulting from the degeneration of nigral dopaminergic neurons and disruption of nigrostriatal dopaminergic projections. Given the important role of non‐human primates in translational studies, our findings provide better understanding of the complicated evolution of PD.     

Alcohol exposure during development: Impact on the epigenome

Fetal alcohol spectrum disorders represent a wide range of symptoms associated with in utero alcohol exposure. Animal models of FASD have been useful in determining the specific neurological consequences of developmental alcohol exposure, but the mechanisms of those consequences are unclear. Long-lasting changes to the epigenome are proposed as a mechanism of alcohol-induced teratogenesis in the hippocampus. The current study utilized a three-trimester rodent model of FASD to examine changes to some of the enzymatic regulators of the epigenome in adolescence. Combined pre- and post-natal alcohol exposureresulted in a significant increase in DNA methyltransferase activity (DNMT), without affecting histone deacetylase activity (HDAC). Developmental alcohol exposure also caused a change in gene expression of regulators of the epigenome, in particular, DNMT1, DNMT3a, and methyl CpG binding protein 2 (MeCP2). The modifications of the activity and expression of epigenetic regulators in the hippocampus of rodents perinatally exposed to alcohol suggest that alcohol's impact on the epigenome and its regulators may be one of the underlying mechanisms of alcohol teratogenesis.