[Advances in synthesis methods and applications of microporous organic networks for sample preparation]

Sample pretreatment is an essential step in chromatographic analysis. Solid phase extraction (SPE) is a widely used sample pretreatment method. In SPE, the quality of the adsorbent directly affects the adsorption and enrichment efficiency of the target compounds as well as the sensitivity and selectivity of the pretreatment and subsequent analysis. Therefore, the selection and development of adsorbents has become a research hotspot. Microporous organic networks (MONs) are a novel type of covalent organic materials that are synthesized by the Sonogashira reaction of aromatic alkynes and aromatic halides. These networks have the advantages of modifiable structures, large specific surface areas, high porosity, and simple synthesis methods. This paper reviews the synthesis and functional modification methods of MONs, with an emphasis on their applications in sample pretreatment. Future development trends are also prospected. In terms of synthesis, the preparation methods for MON-based materials have progressed from reflux and solvothermal synthesis to room-temperature synthesis, the conditions of which tend to be milder and more efficient. In terms of functional modification, the introduction of macromolecules and active groups (including amino, hydroxyl, and carboxylic groups) can increase the selectivity and active sites of MON-based materials. The combination of MONs with Fe3O4, SiO2, and metal organic frameworks yields core-shell-structured MONs. Furtherly, they can be calcined and etched to form porous carbon structures or hollow multilayer materials. Functionalized MONs and their composite materials have multiple interaction mechanisms (e. g., hydrogen bonding, hydrophobic, electrostatic, and π-π interactions) with various target compounds, thereby realizing their efficient extraction. MONs can be used as adsorbent materials in SPE, Solid phase microextraction, dispersed solid phase extraction, magnetic solid phase extraction, and other pretreatment methods. When combined with chromatography and chromatography-mass spectrometry, MONs achieve good adsorption effects and high sensitivity, demonstrating the application potential of these materials in sample pretreatment.

Annual review of capillary electrophoresis technology in 2021

该文为2021年毛细管电泳(capillary electrophoresis, CE)技术年度回顾。归纳总结了以“capillary electrophoresis-mass spectrometry”或“capillary isoelectric focusing”或“micellar electrokinetic chromatography”或“capillary electrophoresis”为关键词在ISI Web of Science数据库中进行主题检索(排除“capillary electrochromatography”“microchip”和“capillary monolithic column”)得到的2021年CE技术相关研究论文291篇,以及中文期刊《色谱》和《分析化学》中相关研究论文9篇。重点介绍了影响因子(IF)≥10.0的Coordination Chemistry Reviews, Angewandte Chemie-International Edition, Nature Protocols, TrAC-Trends in Analytical Chemistry, Signal Transduction and Targeted Therapy发表的7篇论文;以及影响因子5~10之间的代表性期刊Analytical Chemistry, Analytica Chimica Acta, Talanta和Food Chemistry的42篇论文;对影响因子小于5但CE技术报道较为集中的Journal of Chromatography A和Electrophoresis,国内重要的中文期刊《色谱》和《分析化学》中的代表性工作进行了概述。该文根据国际通用学术水平评价指标之一的影响因子选择期刊,结合期刊发表CE论文代表性工作进行介绍,便于读者快速了解毛细管电泳技术在过去一年的重要研究进展。

miR-431-5p Regulates Apoptosis of Cardiomyocytes After Acute Myocardial Infarction via Targeting Selenoprotein T

Acute myocardial infarction (AMI) represents the acute manifestation of coronary artery disease. In recent years, microRNAs (miRNAs) have been extensively studied in AMI. This study focused on the role of miR-431-5p in AMI and its effect on cardiomyocyte apoptosis after AMI. The expression of miR-431-5p was analyzed by quantitative real-time PCR (qRT-PCR). By interfering with miR-431-5p in hypoxia-reoxygenation (H/R)-induced HL-1 cardiomyocytes, the effect of miR-431-5p on cardiomyocyte apoptosis after AMI was examined. The interaction between miR-431-5p and selenoprotein T (SELT) mRNA was verified by dual-luciferase reporter assay. Cell apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and flow cytometry. Cell viability was examined by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay. The results of qRT-PCR showed that the expression of miR-431-5p in AMI myocardial tissues and H/R-induced HL-1 cardiomyocytes was significantly increased. After interfering with miR-431-5p, the expression of SELT in HL-1 cells was up-regulated, cell apoptosis was decreased, cell viability was increased, and lactate dehydrogenase (LDH) activity was decreased. The dual-luciferase reporter assay confirmed the targeting relationship between miR-431-5p and SELT1 3’ untranslated region (UTR). In H/R-induced HL-1 cells, the simultaneous silencing of SELT and miR-431-5p resulted in a decrease of Bcl-2 expression, an increase of Bax expression, and an increase of cleaved-caspase 3 expression compared with silencing miR-431-5p alone. Also, cell viability was decreased, while LDH activity was increased by the simultaneous silencing of SELT and miR-431-5p. Interfering miR-431-5p protected cardiomyocytes from AMI injury via restoring the expression of SELT, providing new ideas for the treatment of AMI.

Suckling calves (Bos taurus) with pica exhibit blood metabolome alterations

The aim of this study was to evaluate the changes of blood metabolomics in calves with pica, which causes serious harm to livestock. Two groups, each comprising 12 calves of approximately 3 weeks old and of similar weight were selected as subjects; Group A calves were control animals in good condition and Group B calves (pica animals) had rough hair, emaciation, flaccid forestomach, diarrhoea, and stunted development. Blood samples were collected from the tail root vein. Masslynx 4.1 software (Waters Company) was used to pre-process data, which were then analysed by principal component analysis, partial least squares discriminant analysis, and orthogonal partial least squares discriminant analysis. Twenty potential biomarkers were closely related to the occurrence of pica, viz. GDP-glucose, UDP-glucose, proline, creatine, arginine, glutamine, citrulline, urea, alanine, methionine, serine, glycerate, cysteine, spermine, spermidine, carnitine, xanthurenic acid, kynurenine, and thyroxine. Metabolic pathway analysis showed that, in calves, pica resulted in decreased antioxidant capacity; disruption of the mutual transformation between pentose and glucuronic acid; abnormal metabolism of cysteine, methionine, serine, arginine, and proline; impairment of lipid metabolism; reduced immunity; increased intestinal permeability; and elevated central nervous excitability. Calves with pica exhibit disruption of various metabolic pathways.

2Hz-Electroacupuncture Attenuates Heroin-Seeking Behaviors via Adjusts CB1-Rs and CB2-Rs Expression in Relapse-Relevant Brain Regions of Heroin Self-Administration Rats

Opiate addiction has a high rate of relapse. The accumulating evidence shows that electroacupuncture (EA) may be effective for the treatment of opiate relapse. However, the change of expression of CB1-Rs and CB2-Rs involve in 2Hz EA anti-relapse pathway is still unclear. To explore the changes of expression of CB1-Rs and CB2-Rs, heroin self-administration (SA) model rats were adopted and treated using 2Hz EA. The expressions of CB1-Rs and CB2-Rs were observed using immunohistochemistry method. The results showed that, compared with the control group, active pokes in the heroin-addicted group increased, while the active pokes decreased significantly in 2Hz EA group compared with heroin-addicted group. Correspondingly, the expression of CB1-Rs in prefrontal cortex (PFC), hippocampus (Hip), nucleus accumbens (NAc) and ventral tegmental area (VTA) all increased significantly while the expression of CB2-Rs in those relapse-relevant brain regions decreased obviously in heroin-addicted group when compared with the control group. In addition, the expression of CB1-Rs obviously decreased in the 2Hz EA group while the expression of CB2-Rs in those relapse-relevant brain regions increased significantly when compared with the heroin-addicted group. It indicated that 2Hz EA could attenuate the heroin-evoked seeking behaviors effectively. The anti-relapse effects of 2Hz EA might be related to the decrease of CB1-Rs and increase of CB2-Rs expression in relapse-relevant brain regions of heroin SA rats.

Impact of hepatitis B on mortality and specific causes of death in adults with and without HIV co-infection in NYC, 2000-2011

High rates of immigration from endemic countries contribute to the high chronic hepatitis B (HBV) prevalence in New York City (NYC) compared to the United States overall, i.e. about 1 million individuals. We describe the impact of HBV infection on mortality and specific causes of death in NYC. We matched surveillance and vital statistics mortality data collected from 2000 to 2011 by the New York City Department of Health and Mental Hygiene (DOHMH) and analysed demographics and premature deaths (i.e. whether death occurred at <65 years) in persons with and without chronic HBV or HIV infection (excluding those with hepatitis C). From 2000 to 2011, a total of 588 346 adults died in NYC. Of all decedents, 568 753 (97%) had no report of HIV or HBV, and 4346 (0·7%) had an HBV report. Of HBV-infected decedents, 1074 (25%) were HIV co-infected. Fifty-five percent of HBV mono-infected and 95% of HBV/HIV co-infected decedents died prematurely. HBV disproportionately impacts two subgroups: Chinese immigrants and HIV-infected individuals. These two subgroups are geographically clustered in different neighbourhoods of NYC. Tailoring prevention and treatment messages to each group is necessary to reduce the overall burden of HBV in NYC.

TWO-GRID METHODS FOR MAXWELL EIGENVALUE PROBLEMS

Two new two-grid algorithms are proposed for solving the Maxwell eigenvalue problem. The new methods are based on the two-grid methodology recently proposed by Xu and Zhou [Math. Comp., 70 (2001), pp. 17-25] and further developed by Hu and Cheng [Math. Comp., 80 (2011), pp. 1287-1301] for elliptic eigenvalue problems. The new two-grid schemes reduce the solution of the Maxwell eigenvalue problem on a fine grid to one linear indefinite Maxwell equation on the same fine grid and an original eigenvalue problem on a much coarser grid. The new schemes, therefore, save total computational cost. The error estimates reveals that the two-grid methods maintain asymptotically optimal accuracy, and the numerical experiments presented confirm the theoretical results.

LPS may enhance expression and release of HMGB1 in human nasal epithelial cells in vitro

Chronic rhinosinusitis with nasal polyps is a common disease with still unclear pathophysiologic mechanisms. The airway epithelial barrier has been shown to be involved in different chronic disorders, including rhinitis, nasal polyposis and asthma. High mobility group box 1 (HMGB1), a primarily nuclear protein, is involved in the induction of airway inflammation in patients with chronic rhinosinusitis, allergy, asthma and COPD. Pathogen-derived lipopolysaccharide is widely used as a trigger for inflammation. However, the molecular dialogue between LPS and HMGB1 in the delayed inflammatory processes remains to be explored, and the regulation of HMGB1 release through LPS from epithelial cells has not been extensively studied in patients with chronic rhinosinusitis and nasal polyps. The objective of the present study was to investigate the relocation of HMGB1 in LPS-induced human nasal epithelial cells in vitro. We obtained epithelial cells of nasal polyps from 10 patients requiring surgery for sinusitis at the ENT Department of the Chinese PLA General Hospital. The primary cultured human nasal epithelial (HNE) cells were stimulated with LPS. The expression and translocation of HMGB1 in intracellular and culture supernatants were determined using Western blot and immunofluorescence assay. HMGB1 protein was released in a time-dependent fashion in culture supernatants: in fact, expression of HMGB1 protein in HNE cells showed no significant changes at 0-24 h after exposure to 100 μg/ml LPS, but increased significantly at 48 and 72 hr. Immunofluorescence analysis revealed the transfer of HMGB1 from nuclei to cytoplasm in response to LPS exposure after 24 hr. These data reveal a hitherto unrecognized association between HMGB1 and LPS in human nasal epithelial cells. LPS can affect HMGB1 translocation and release, suggesting the involvement of HMGB1, through inflammatory mediators, in chronic rhinosinusitis with nasal polyps.

Interaction of fibrin with VE-cadherin and anti-inflammatory effect of fibrin-derived fragments

BACKGROUND

The interaction of the fibrin βN-domain with VE-cadherin on endothelial cells is implicated in transendothelial migration of leukocytes, and the β15-42 fragment representing part of this domain has been shown to inhibit this process. However, our previous study revealed that only a dimeric (β15-66)(2) fragment, corresponding to the full-length βN-domain and mimicking its dimeric arrangement in fibrin, bound to VE-cadherin.

OBJECTIVE

To test our hypothesis that dimerization of β15-42-containing fragments increases their affinity for VE-cadherin and ability to inhibit transendothelial migration of leukocytes.

METHODS

Interaction of β15-42-containing fragments with VE-cadherin was characterized by ELISA and surface plasmon resonance. The inhibitory effect of such fragments was tested in vitro with a leukocyte transendothelial migration assay and in vivo with mouse models of peritonitis and myocardial ischemia-reperfusion injury.

RESULTS

First, we prepared the monomeric β15-42 and β15-64 fragments and their dimeric forms, (β15-44)(2) and (β15-66)(2) , and studied their interaction with the fibrin-binding domain of VE-cadherin, VE-cad(3). The experiments revealed that both dimeric fragments bound to VE-cad(3) with high affinity, whereas the affinities of β15-42 and β15-64 were significantly lower. Next, we tested the ability of these fragments to inhibit leukocyte transmigration in vitro and infiltration into the inflamed peritoneum in vivo, and found that the inhibitory effects of the dimers on these processes were also superior. Furthermore, (β15-44)(2) significantly reduced myocardial injury induced by ischemia-reperfusion.

CONCLUSION

The results confirm our hypotheses and indicate that (β15-66)(2) and (β15-44)(2) , which exhibited much higher affinity for VE-cadherin, are highly effective in suppressing inflammation by inhibiting leukocyte transmigration.

[Mutation patterns in the RT region of hepatitis B virus P gene in patients treated with nucleoside/nucleotide analogs]

OBJECTIVE

To analyze mutation patterns in the RT region of hepatitis B virus (HBV) P gene in patients treated with nucleoside or nucleotide analogs.

METHODS

Viral DNA was extracted from 227 serum samples of chronic hepatitis B patients from September, 2005 to March, 2007. The RT region of HBV P gene was PCR-amplified and sequenced.

RESULTS

Known resistant mutations were found in 111 cases (48.9%) among 227 samples, 75 cases with clear therapy history. Novel mutations, including A222T, L229V and S256C, were also found. The incidence of multi-drug resistance in patients sequentially treated with lamivudine and adefovir was 25% (4/16), and none of the patients treated with lamivudine plus adefovir in combination shown multi-drug resistance.

CONCLUSION

The patterns of mutation is complex in nucleotide analogue treated patients. Switching to adefovir in lamivudine resistant patients may lead to multi-drug resistance. Novel mutations identified in this study need further investigation.