[Preparation of porous boron nitride-doped polypyrrole-2,3,3-trimethylindole solid-phase microextraction coating for polycyclic aromatic hydrocarbon detection].

Most polycyclic aromatic hydrocarbons (PAHs), which are persistent organic pollutants, have strong carcinogenicity, teratogenicity, and mutagenicity, and pose serious threats to the ecological environment and human health. Owing to the complexity of the matrix and low PAH content of environmental samples, separating and enriching PAHs in environmental samples is necessary prior to their detection. Solid-phase microextraction (SPME) technology is commonly used to detect PAHs owing to its advantages of simple operation, online connection with other instruments, low solvent usage, and integrability of sampling separation, enrichment, and desorption. The extraction coating is the core of this technology, and the type and thickness of the coating are important factors affecting the sensitivity and accuracy of the analysis. Common commercial extraction coatings include polydimethylsiloxane and quartz fiber; however, these materials have a number of disadvantages, such as poor thermal stability and high cost. Several methods, including electrochemical, sol-gel, molecular imprinting, and other coating methods, have been developed to prepare SPME coatings. Electrochemical methods have attracted considerable attention because of their simplicity, short duration, and high coating stability. In the development of an electrochemical method, the selection of the conductive polymer is of particular importance. Polypyrroles (Ppy) are easily synthesized and have numerous advantages, such as good conductivity and stable chemical properties. Thus, their use as a substrate material for SPME coatings is beneficial for improving the overall stability of the coating. Copolymerization with other polymers can enhance the adsorption performance of such coatings via synergistic effects. When doped with inorganic materials with high thermal stability, the composite coating can exhibit high temperature resistance. In this study, a porous boron nitride-doped Ppy-2,3,3-trimethylindole (Ppy/P2,3,3-TMe@In/BN) composite was prepared as a new SPME copolymer coating to detect three PAHs: naphthalene (NAP), acenaphthene (ANY), and fluorene (FLU). Scanning electron microscopy, thermal stability analysis, Fourier transform infrared spectroscopy, and other techniques were used to characterize the Ppy/P2,3,3-TMe@In/BN composite coating. The results showed that the coating featured a large number of porous and wrinkled dendritic structures, which increased the specific surface area of the composite coating and enabled the extensive enrichment of the three PAHs. When the sample inlet temperature of the chromatograph is 320 ℃, the chromatographic baseline of the coating is basically stable. Compared with commercial coatings, the prepared coating had better thermal stability. The coating formed stable intermolecular forces with the three PAHs owing to its numerous carbon-carbon double bonds (C=C), hydrogen bonds, and other structures, thereby achieving excellent enrichment of the target analytes. Compared with Ppy, Ppy/PIn, Ppy/P2,3,3-TMe@In, Ppy/BN, and polydimethylsiloxane (PDMS) coatings, the prepared Ppy/P2,3,3-TMe@In/BN composite coating exhibited better extraction effects for the three PAHs. The Ppy/P2,3,3-TMe@In/BN composite coating was polymerized on the surface of a stainless-steel wire by cyclic voltammetry and combined with gas chromatography-hydrogen flame ionization detection (GC-FID) to optimize the conditions influencing the extraction and separation of the three PAHs, thereby establishing a highly sensitive analytical method for detecting NAP, ANY, and FLU. This method had low limits of detection (LODs) of 10.6-14.5 ng/L (S/N=3) and high stability. The SPME-GC-FID method was used to detect the three PAHs in two environmental water samples, and a small amount of ANY (1.39 µg/L) was detected in one water sample. Satisfactory recoveries (82.5%-113.9%) were obtained when both water samples were spiked with the three PAHs at three levels. The experimental results indicate that the established analytical method can detect the three PAHs in environmental water samples.

The value of vestibular graviceptive pathway evaluation in the diagnosis of unilateral peripheral vestibular dysfunction.

BACKGROUND: Evaluation of vestibular graviceptive pathway (VGP) in patients with unilateral peripheral vestibular dysfunction (UPVD) has received increasing attention from researchers. The study aimed to investigate the value of VGP evaluation in the diagnosis of UPVD. METHODS: Ninety-five UPVD patients were divided into attack and remission phase groups. VGP evaluation-related indicators, including subjective visual vertical (SVV), subjective visual horizontal (SVH), head tilt, ocular torsion (OT), and skew deviation (SD), were measured, and their correlations with cochleovestibular function test results were analyzed. The possible etiologies of contralesional VGP (c-VGP) were analyzed. RESULTS: Positive rates of SVV, SVH, OT, and SD were significantly higher, and the degrees of SVV, SVH, and OT were significantly greater in the attack phase group than the remission phase group. The sides with abnormal VGP evaluation results were correlated with the sides with hearing loss, abnormal caloric, and video head impulse test (vHIT) results. A total of 14 patients showed c-VGP, and possible etiologies included contralateral benign paroxysmal positional vertigo (n = 4), bilateral hearing loss (n = 8), bilateral vHIT gain reduction (n = 1), autoimmune diseases (n = 6), vascular risk factors (n = 6), lacunar infarction (n = 3), and endolymphatic hydrops (n = 3). CONCLUSIONS: Alterations in SVV, SVH, OT, and SD were noted in UPVD patients in different phases, which are presumed to be related to dynamic vestibular compensation; correlations between VGP evaluation results and cochleovestibular function test results indicate that VGP evaluation may be helpful for the diagnosis of the side affected in UPVD; the presence of c-VGP may be related to bilateral labyrinth lesions or endolymphatic hydrops on the affected side; and the involvement of autoimmune mechanisms also deserves attention.

[Somatic Mutations of Acquired Aplastic Anemia].

Aplastic anemia (AA) and myelodysplastic syndrome (MDS) are clonal diseases with hemopoietic stem cell (HSC) abnormalities,which are sometimes difficult to be distinguished from each other.The development of molecular detection techniques has facilitated our understanding of the molecular pathogenesis of the two diseases.This article reviewed the somatic mutation (SM) and cytogenetic changes of AA,and analyzed their molecular relationship with MDS and their roles in disease transformation.The most common somatic change in AA is the loss of PIGA and HLA alleles,which,along with trisomy 8 and del(13q),is related to the immune pathogenesis of AA.Among the 5 most common mutations in AA,PIGA and BCOR/BCORL1 mutations are related to a good prognosis,while DNMT3A and ASXL1 mutations are likely associated with clonal evolution and a poor prognosis.The risk factors for secondary MDS after AA include SM and cytogenetic changes such as del(7q) associated with poor prognosis,prolonged disease duration after diagnosis,onset age of AA,and leukocyte telomere attrition.Although role of SM in disease progression remains unclear because of its dynamic change and unknown significance,prognostic assessment based on the monitoring of SM and clinical features may guide the treatment.

[Evaluation of the Efficacy of Cyclosporin A Combined with Recombined Human Erythropoietin in the Treatment of Patients with Chronic Aplastic Anemia].

Objective To compare the efficacy and safety of cyclosporin A(CsA)and CsA combined with recombined human erythropoietin(rhEPO)in the treatment of patients with chronic aplastic anemia(CAA).Methods Data of 79 patients with CAA treated at Department of Hematology,PUMC Hospital between January 2016 and June 2018 were collected for retrospective analysis.Forty-five patients were treated with CsA+rhEPO,and the other 34 patients with CsA alone.All the enrolled patients were treated for at least 1.5-2.0 years and followed for at least 1.0 year.The efficacy,side effects,long-term outcomes were compared between the two groups,and factors that may influence the efficacy were analyzed.Results The patients treated with CsA+rhEPO included 14 males and 31 females,with a median age of 43(19,73)years old.The median treatment duration of CsA and rhEPO was 26(12,38)and 4(3,6)months,respectively,and the median followed-up time was 24(12,42)months.The patients treated with CsA alone included 16 males and 18 females,with a median age of 36(16,85)years old.The median CsA treatment duration was 24(12,40)months and the median follow-up time was 25(12,40)months.There was no statistical difference in baseline characteristics between the two groups(all P>0.05).After 6 months of treatment,CsA+rhEPO group had higher overall response(OR)rate(55.6% vs. 31.3%;χ 2=4.456,P=0.040)and partial response(PR)rate(53.3% vs. 25.0%;χ2=6.181,P=0.019)than CsA group,and the complete response(CR)rate showed no statistical difference between the two groups(2.2% vs. 6.3%;χ2=0.810,P=0.567).The CR,PR,and OR rates showed no statistical difference between the two groups after 3 and 12 months of treatment and at the end of follow-up(all P>0.05).Similarly,the hemoglobin level at the sixth month of treatment with CsA+rhEPO was higher than that with CsA alone [(102.6±24.0)g/L vs.(90.3±29.1)g/L;t=2.017,P=0.047].However,it showed no significant difference between the two groups at other time points(all P>0.05).The side effects,including an increase in serum creatinine,slight increase in bilirubin,increase in aminotransferase,mild to moderate gingival hyperplasia,gastrointestinal reaction,and muscular fibrillation,had no significant differences between the two groups(all P>0.05),except that 11.1%(5/45)patients in the CsA+rhEPO group reported soreness at the injection site.The two groups showed similar rates of clonal revolution during the follow-up period and no death.No clinical factor was found for prediction of the efficacy of CsA+rhEPO. Conclusion CsA+rhEPO has higher OR rate and hemoglobin level than CsA alone at the sixth month of treatment,and it has similar side effects compared with CsA alone.

Rac1 conditional deletion attenuates retinal ganglion cell apoptosis by accelerating autophagic flux in a mouse model of chronic ocular hypertension.

Autophagy has a fundamental role in maintaining cell homeostasis. Although autophagy has been implicated in glaucomatous pathology, how it regulates retinal ganglion cell (RGC) injury is largely unknown. In the present work, we found that biphasic autophagy in RGCs occurred in a mouse model of chronic ocular hypertension (COH), accompanied by activation of Rac1, a member of the Rho family. Rac1 conditional knockout (Rac1 cKO) in RGCs attenuated RGC apoptosis, in addition to blocking the increase in the number of autophagosomes and the expression of autophagy-related proteins (Beclin1, LC3-II/I, and p62) in COH retinas. Electron micrograph and double immunostaining of LAMP1 and LC3B showed that Rac1 cKO accelerated autolysosome fusion in RGC axons of COH mice. Inhibiting the first autophagic peak with 3-methyladenine or Atg13 siRNA reduced RGC apoptosis, whereas inhibiting the second autophagic peak with 3-MA or blocking autophagic flux by chloroquine increased RGC apoptosis. Furthermore, Rac1 cKO reduced the number of autophagosomes and apoptotic RGCs induced by rapamycin injected intravitreally, which suggests that Rac1 negatively regulates mTOR activity. Moreover, Rac1 deletion decreased Bak expression and did not interfere with the interaction of Beclin1 and Bcl-2 or Bak in COH retinas. In conclusion, autophagy promotes RGC apoptosis in the early stages of glaucoma and results in autophagic cell death in later stages. Rac1 deletion alleviates RGC damage by regulating the cross talk between autophagy and apoptosis through mTOR/Beclin1-Bak. Interfering with the Rac1/mTOR signaling pathway may provide a new strategy for treating glaucoma.

EphrinB/EphB forward signaling in Müller cells causes apoptosis of retinal ganglion cells by increasing tumor necrosis factor alpha production in rat experimental glaucomatous model.

It was previously shown that EphB/ephrinB reverse signaling in retinal ganglion cells (RGCs) is activated and involved in RGC apoptosis in a rat chronic ocular hypertension (COH) model. In the present work, we first show that ephrinB/EphB forward signaling was activated in COH retinas, and RGC apoptosis in COH retinas was reduced by PP2, an inhibitor of ephrinB/EphB forward signaling. We further demonstrate that treatment of cultured Müller cells with ephrinB1-Fc, an EphB1 activator, or intravitreal injection of ephrinB1-Fc in normal rats induced an increase in phosphorylated EphB levels in these cells, indicating the activation of ephrinB/EphB forward signaling, similar to those in COH retinas. The ephrinB1-Fc treatment did not induce Müller cell gliosis, as evidenced by unchanged GFAP expression, but significantly up-regulated mRNA and protein levels of tumor necrosis factor-α (TNF-α) in Müller cells, thereby promoting RGC apoptosis. Production of TNF-α induced by the activation of ephrinB/EphB forward signaling was mediated by the NR2B subunit of NMDA receptors, which was followed by a distinct PI3K/Akt/NF-κB signaling pathway, as pharmacological interference of each step of this pathway caused a reduction of TNF-α production, thus attenuating RGC apoptosis. Functional analysis of forward and reverse signaling in such a unique system, in which ephrin and Eph exist respectively in a glial element and a neuronal element, is of theoretical importance. Moreover, our results also raise a possibility that suppression of ephrinB/EphB forward signaling may be a new strategy for ameliorating RGC apoptosis in glaucoma.

Ghrelin Attenuates Retinal Neuronal Autophagy and Apoptosis in an Experimental Rat Glaucoma Model.

Purpose: Ghrelin, a natural ligand for the growth hormone secretagogue receptor type 1a (GHSR-1a), may protect retinal neurons against glaucomatous injury. We therefore characterized the underlying mechanism of the ghrelin/GHSR-1a-mediated neuroprotection with a rat chronic intraocular hypertension (COH) model. Methods: The rat COH model was produced by blocking episcleral veins. A combination of immunohistochemistry, Western blot, TUNEL assay, and retrograde labeling of retinal ganglion cells (RGCs) was used. Results: Elevation of intraocular pressure induced a significant increase in ghrelin and GHSR-1a expression in retinal cells, including RGCs and Müller cells. Western blot confirmed that the protein levels of ghrelin exhibited a transient upregulation at week 2 after surgery (G2w), while the GHSR-1a protein levels were maintained at high levels from G2w to G4w. In COH retinas, the ratio of LC3-II/LC-I and beclin1, two autophagy-related proteins, were increased from G1w to G4w, and the cleavage product of caspase3, an apoptotic executioner, was detected from G2w to G4w. Intraperitoneal injection of ghrelin significantly increased the number of surviving RGCs; inhibited the changes of LC3-II/LC-I, beclin1, and the cleavage products of caspase3; and reduced the number of TUNEL-positive cells in COH retinas. Ghrelin treatment also reversed the decreased levels of p-Akt and p-mTOR, upregulated GHSR-1a protein levels, and attenuated glial fibrillary acidic protein levels in COH retinas. Conclusions: All these results suggest that ghrelin may provide neuroprotective effect in COH retinas through activating ghrelin/GHSR-1a system, which was mediated by inhibiting retinal autophagy, ganglion cell apoptosis, and Müller cell gliosis.

[Effect of Three Typical Disinfection Byproducts on Bacterial Antibiotic Resistance].

The effect of typical disinfection byproducts (DBPs) on bacterial antibiotic resistance was investigated in this study. chlorodibromomethane (CDBM), iodoacetic acid (IAA) and chloral hydrate (CH) were selected, which belong to trihalomethanes (THMs), haloacetic acids (HAAs) and aldehydes, respectively. After exposure to the selected DBPs, the resistance change of the tested strains to antibiotics was determined. As a result, all of the three DBPs induced Pseudomonas aeruginosa PAO1 to gain increased resistance to the five antibiotics tested, and the DBPs ranked as IAA > CH > CDBM according to their enhancement effects. Multidrug resistance could also be enhanced by treatment with IAA. The same result was observed in Escherichia coli K12, suggesting that the effect of DBPs on antibiotic resistance was a common phenomenon. The mechanism was probably that DBPs stimulated oxidative stress, which induced mutagenesis. And the antibiotic resistance mutation frequency could be increased along with mutagenesis. This study revealed that the acquisition of bacterial antibiotic resistance might be related to DBPs in drinking water systems. Besides the genotoxicological risks, the epidemiological risks of DBPs should not be overlooked.

[Using flow cytometry to explore the changes of Sphingomonas sp. GY2B bacterial surface characteristics in the process of degrading phenanthrene].

The first step of biodegradation is the contact of microorganism and pollutants, in order to examine the influence of phenanthrene on Sphingomonas sp. GY2B's surface properties during its degrading process, the bacteria was cultivated at different conditions, and detected by flow cytometry combined with fluorescent dyes for its surface changes. The results indicated that, the membrane structure had been certainly damaged during the degrading process, leading to an increased membrane permeability. Moreover, the destruction of bacteria membrane integrity became more serious with a higher pollutant concentration. At the concentration of 300 mg x L(-1), the ratio of stained bacterial cells/unstained cells was 12.44 after cultured for 60 h, while at 100 mg x L(-1) and 1.2 mg x L(-1), the ratios were 1.95 and 1.11, respectively. The results of fourier transform infrared (FT-IR) absorbance spectroscopy detection, the discrimination of death, injured and intact cells, and Zeta potential detection further verified the bacterial cell surface permeability changes. Flow cytometry combined with fluorescent dye propidium iodide was used to monitor the changes of bacterial membrane integrity on single-cell level which exhibited a good potential for exploring the changes of bacterial surface properties during the degrading progress and more deeply for investigating the degradation mechanism.