Comparison of carotid atherosclerotic plaque characteristics by high-resolution black-blood MR imaging between patients with first-time and recurrent acute ischemic stroke

BACKGROUND AND PURPOSE

It has been shown that patients with a first ischemic stroke are at high risk of developing recurrent stroke due to carotid atherosclerotic plaque rupture. However, no one has defined the difference in plaques between initial and recurrent stroke. This study sought to investigate the characteristics of carotid plaque between patients with first-time and recurrent acute ischemic stroke by using MR imaging.

MATERIALS AND METHODS

Eighty-nine patients with recent acute ischemic stroke were recruited. All subjects underwent carotid high-resolution black-blood MR imaging. The index carotid arteries, defined as the arteries responsible for the ipsilateral stroke, were analyzed quantitatively and qualitatively. Carotid plaque burden and compositional features between patients with first-time and recurrent ischemic stroke were compared.

RESULTS

Of 89 recruited patients, 51 had first-time stroke and 38 had recurrent stroke. The mean WA, WT, and PWV were greater in patients with recurrent stroke than in patients with first-time stroke (all, P < .05). Compared with patients with first-time stroke, those with recurrent stroke showed significantly higher prevalence of calcification (44.7% versus 23.5%, P = .035) as well as a larger volume of LRNC (179.14 ± 254.81 mm(2) versus 71.65 ± 111.15 mm(2), P = .027). IPH or fibrous cap rupture or both were observed in 15.8% of patients with recurrent stroke and 3.9% of patients with first-time stroke.

CONCLUSIONS

Carotid plaques in patients with recurrent ischemic stroke are significantly aggravated compared with those in patients with first-time stroke, and monitoring carotid plaques in patients with initial stroke by MR imaging may be helpful for secondary stroke prevention.

Reverse line blot hybridisation screening of Pseudallescheria/Scedosporium species in patients with cystic fibrosis

The PCR-RLB (reverse line blot hybridisation) was applied as a molecular technique for the detection of members of Pseudallescheria and Scedosporium from sputum of patients with cystic fibrosis (CF). Fifty-nine sputum samples were collected from 52 CF patients, which were analysed by culture and PCR-RLB. Conventional and semi-selective culture yielded five positive samples, but the PCR-RLB hybridisation assay permitted the detection of members of Pseudallescheria/Scedosporium in 32 out of 52 patients (61.5%). In total, PCR-RLB yielded 47 positives. Pseudallescheria apiosperma was detected in 20 samples, while Pseudallescheria boydii and Pseudallescheria aurantiacum were detected in 17 and eight samples, respectively. Six samples gave a positive reaction with two distinct species-specific probes and one sample with three probes. In conclusion, the PCR-RLB assay described in this study allows the detection of Scedosporium spp. in CF sputum samples and the identification of Pseudallescheria apiosperma, P. boydii, S. aurantiacum, Scedosporium prolificans and Pseudallescheria minutispora.

Anisotropy property of CdS and PbS quantum dots encapsulated in silica film with uniformly oriented mesochannel

In this paper, hybrid film of mesoporous silica film with oriented mesochannels and semiconductor quantum dot has been prepared. Encapsulation of CdS and PbS within the oriented mesochannels leads to a regular arrangement at the macro scale. The hybrid film thus obtained showed remarkable anisotropic photoelectronic properties due to the confinement effect of the oriented mesochannels. Furthermore, due to the independence of the orientations of the mesochannels on the substrate, bilayer films containing both CdS and PbS could be prepared. This design has allowed an extension of the range of light absorption by the thin film as well as an amplification of the response to external photoelectronic effects. Such a hybrid film may prove useful in the design of anisotropic electrodes and electronic nanodevices.

Abnormal epigenetic modifications in peripheral blood mononuclear cells from patients with alopecia areata

BACKGROUND

Alopecia areata (AA) is a hair loss disease caused by T-cell-mediated autoimmune reactions against anagen-stage hair follicles. Although the exact aetiology is poorly understood, there is evidence to suggest that both genetic and environmental factors are involved in AA pathogenesis.

OBJECTIVES

To analyse DNA methylation and histone modification patterns in peripheral blood mononuclear cells (PBMCs) of patients with AA.

METHODS

PBMC samples were obtained from 25 patients with AA and 20 healthy controls. Global DNA methylcytosine levels, as well as histone acetylation and methylation levels, were measured by enzyme-linked immunosorbent assay. mRNA expression levels were determined using real-time quantitative reverse transcription-polymerase chain reaction.

RESULTS

Genomic DNA methylation in PBMCs of patients with AA was increased relative to controls. DNMT1, MBD1 and MBD4 expression levels were significantly higher in AA PBMCs than in controls, and DNMT1 transcription levels positively correlated with global DNA methylation levels in patient samples. Histone H3 acetylation was significantly increased and histone H3 lysine 4 methylation was significantly decreased in patient PBMCs compared with healthy controls. Histone H3 acetylation levels were positively correlated with AA disease severity, and with RANTES (CCL5) mRNA expression in PBMCs of patients with AA. These changes were accompanied by increased p300 (EP300), histone deacetylase 1 (HDAC1), myeloid/lymphoid or mixed lineage leukemia (MLL), SET7/9 (SETD7), G9A (EHMT2), JMJD2C (KDM4C) and JARID1A (KDM5A) expression, as well as reduced HDAC2, HDAC7, LSD1 (KDM1A), JMJD2A (KDM4A) and JMJD2B (KDM4B) expression.

CONCLUSIONS

DNA methylation and histone modification status are altered in PBMCs of patients with AA, possibly due to the deregulation of epigenetic regulatory genes. These changes may contribute to the activation of pathological immune responses in AA.

Bio-inspired hierarchical self-assembly of nanotubes into multi-dimensional and multi-scale structures

As inspired from nature's strategy to prepare collagen, herein we report a hierarchical solution self-assembly method to prepare multi-dimensional and multi-scale supra-structures from the building blocks of pristine titanate nanotubes (TNTs) around 10 nm. With the help of amylose, the nanotubes was continuously self-assembled into helically wrapped TNTs, highly aligned fibres, large bundles, 2D crystal facets and 3D core-shell hybrid crystals. The amyloses work as the glue molecules to drive and direct the hierarchical self-assembly process extending from microscopic to macroscopic scale. The whole self-assembly process as well as the self-assembly structures were carefully characterized by the combination methods of (1)H NMR, CD, Hr-SEM, AFM, Hr-TEM, SAED pattern and EDX measurements. A hierarchical self-assembly mechanism was also proposed.

Mechanical responsiveness of the endothelial cell of Schlemm's canal: scope, variability and its potential role in controlling aqueous humour outflow

Primary open-angle glaucoma is associated with elevated intraocular pressure, which in turn is believed to result from impaired outflow of aqueous humour. Aqueous humour outflow passes mainly through the trabecular meshwork (TM) and then through pores formed in the endothelium of Schlemm's canal (SC), which experiences a basal-to-apical pressure gradient. This gradient dramatically deforms the SC endothelial cell and potentially contributes to the formation of those pores. However, mechanical properties of the SC cell are poorly defined. Using optical magnetic twisting cytometry and traction force microscopy, here we characterize the mechanical properties of primary cultures of the human SC cell, and for the first time, the scope of their changes in response to pharmacological agents that are known to modulate outflow resistance. Lysophosphatidic acid, sphingosine-1-phosphate (S1P) and thrombin caused an increase in cell stiffness by up to 200 per cent, whereas in most cell strains, exposure to latrunculin A, isoproterenol, dibutryl cyclic-AMP or Y-27632 caused a decrease in cell stiffness by up to 80 per cent, highlighting that SC cells possess a remarkably wide contractile scope. Drug responses were variable across donors. S1P, for example, caused 200 per cent stiffening in one donor strain but only 20 per cent stiffening in another. Isoproterenol caused dose-dependent softening in three donor strains but little or no response in two others, a finding mirrored by changes in traction forces and consistent with the level of expression of β(2)-adrenergic receptors. Despite donor variability, those drugs that typically increase outflow resistance systematically caused cell stiffness to increase, while in most cases, those drugs that typically decrease outflow resistance caused cell stiffness to decrease. These findings establish the endothelial cell of SC as a reactive but variable mechanical component of the aqueous humour outflow pathway. Although the mechanism and locus of increased outflow resistance remain unclear, these data suggest the SC endothelial cell to be a modulator of outflow resistance.

The role of leptin receptor gene polymorphisms in determining the susceptibility and prognosis of NSCLC in Chinese patients

AIM

Although the role of genetic polymorphisms of leptin receptor (LEPR) gene in several cancers has been documented, the association between polymorphisms of LEPR gene and lung cancer remains unknown.

METHOD

We recruited 744 patients histologically diagnosed as non-small cell lung cancer (NSCLC) and 832 controls in this study. Polymorphism analysis of LEPR gene was performed by PCR-restriction fragment length polymorphisms.

RESULTS

The Arg/Arg genotype and Arg allele frequency of the Gln223Arg in LEPR gene were significantly prevalent in NSCLC subjects than in controls (P < 0.05). The odd ratio (OR) for NSCLC in Arg/Arg genotype carriers was 3.12 (95% CI: 2.25-4.56, P = 0.0023, with Gln/Gln as reference). There were no significant differences in the genotype distributions and allele frequencies of Lys109Arg and Lys656Asn in LEPR gene between NSCLC cases and controls (All P > 0.05). The Arg/Arg carriers had higher cancer grade and higher TNM stage. Kaplan-Mier curve showed the Arg/Arg carriers had a poor prognosis than those with Gln/Arg and Gln/Gln genotype carriers. Cox proportional hazards regression models showed the hazard ratio (HR) for death associated with Arg/Arg genotype was 3.43 (95% CI: 2.45-5.92, compared with Gln/Gln carriers, P = 0.002). The other two SNPs of LEPR gene did not show this trend in the evaluation of their role in determining the prognosis of NSCLC subjects.

CONCLUSION

The results suggest the polymorphisms of Gln223Arg, rather than Lys109Arg and Lys656Asn, may be used as a molecular marker for progression and prognosis of NSCLC.

Magnetic resonance lymphography at 3T: a promising noninvasive approach to characterise inguinal lymphatic vessel leakage

PURPOSE

To explore the feasibility of using 3T high-resolution MR lymphangiography to characterize inguinal lymphatic vessel leakage (LVL).

MATERIALS AND METHODS

Sixteen patients with known inguinal LVL underwent 3T MR lymphangiography and T(2)-weighted imaging. The presence or absence of inguinal LVL and the responsible lymphatic vessels were determined using the above imaging modalities and confirmed by surgical procedure. Afterwards, fifteen patients with recurring LVL following conservative treatment were referred to surgical intervention.

RESULTS

Specific inguinal LVL enhancement patterns and leaking lymphatic vessels were detected in 15 of 16 patients. Compared to the SNR of enhanced lymph nodes, that of the enhanced LVL was significantly greater (t = 7.149, p < 0.01), thereby making it possible to differentiate between LVL sites and enhancing inguinal lymph nodes. Furthermore, the steepest contrast enhancement curve slope of enhanced LVL was lower than that of enhanced lymph nodes (t = -2.860, p = 0.02). After MR diagnosis, 15 patients successfully underwent open exploration and ligation of the leaking lymphatic vessel. Clinical follow-up did not demonstrate recurrence of lymphatic fluid in the groin.

CONCLUSIONS

High-resolution MR lymphangiography combined with T(2)-weighted imaging is a promising approach to identifying specific features of lymphatic vessel leakage in the groin.

Targeted therapy of SMMC-7721 liver cancer in vitro and in vivo with carbon nanotubes based drug delivery system

A new type of drug delivery system (DDS) involved chitosan (CHI) modified single walled carbon nanotubes (SWNTs) for controllable loading/release of anti-cancer doxorubicin (DOX) was constructed. CHI was non-covalently wrapped around SWNTs, imparting water-solubility and biocompatibility to the nanotubes. Folic acid (FA) was also bounded to the outer CHI layer to realize selective killing of tumor cells. The targeting DDS could effectively kill the HCC SMMC-7721 cell lines and depress the growth of liver cancer in nude mice, showing superior pharmaceutical efficiency to free DOX. The results of the blood routine and serum biochemical parameters, combined with the histological examinations of vital organs, demonstrating that the targeting DDS had negligible in vivo toxicity. Thus, this DDS is promising for high treatment efficacy and low side effects for future cancer therapy.

Histone modifications and methyl-CpG-binding domain protein levels at the TNFSF7 (CD70) promoter in SLE CD4+ T cells

Abstract: In systemic lupus erythematosus (SLE), T lymphocytes overexpress CD70 ( TNFSF7 gene), leading to the synthesis of autoreactive IgGs. CD70 upregulation in SLE CD4+ T cells is associated with hypomethylation of TNFSF7 promoter. In this study, we explored histone modifications in the TNFSF7 promoter region in SLE CD4+ T cells, and characterized the effects of a DNA methyltransferase inhibitor (5-azaC) and a histone deacetylase inhibitor (TSA) on CD70 expression. We found that CD70 mRNA was significantly increased in active lupus CD4+ T cells, and in control cells treated with 5-azaC, TSA, or both. Histone H3 acetylation and dimethylated H3 lysine 4 (H3K4me2) levels were significantly elevated in patients with lupus, and both factors correlated positively with disease activity. MeCP2 protein levels within the TNFSF7 promoter decreased in patients with active lupus. Treatment of CD4+ T cells with 5-azaC alone significantly raised H3K4 dimethyl levels at the TNFSF7 locus. TSA treatment significantly increased H3 and H4 acetylation levels, as well as levels of H3K4 dimethylation at the TNFSF7 locus. Treatment with 5-azaC plus TSA enhanced H3 acetylation levels. These findings indicate that aberrant histone modifications within the TNFSF7 promoter may contribute to the development of lupus by increasing CD70 expression in CD4+ T cells.

Nfat1 regulates adult articular chondrocyte function through its age-dependent expression mediated by epigenetic histone methylation

The development of disease-modifying pharmacologic therapy for osteoarthritis (OA) currently faces major obstacles largely because the regulatory mechanisms for the function of adult articular chondrocytes remain unclear. We previously demonstrated that lack of Nfat1, one of the nuclear factor of activated T cells (NFAT) transcription factors, causes OA-like changes in adult mice. This study aimed to identify whether Nfat1 specifically regulates adult articular chondrocyte function and its age-dependent regulatory mechanism using both Nfat1-deficient and wild-type mice. Deletion of Nfat1 did not induce OA-like articular chondrocyte dysfunction (e.g., overexpression of proinflammatory cytokines and matrix-degrading proteinases) until the adult stage. RNAi-mediated Nfat1 knockdown caused dysfunction of wild-type adult articular chondrocytes. Nfat1 expression in wild-type articular chondrocytes was low in the embryonic but high in the adult stage. Chromatin immunoprecipitation assays demonstrated that an increase in Nfat1 expression in articular chondrocytes was associated with increased H3K4me2 (a histone modification linked to transcriptional activation), whereas a decrease in Nfat1 expression in articular chondrocytes was correlated with increased H3K9me2 (a histone modification linked to transcriptional repression). Knockdown of lysine-specific demethylase-1 (Lsd1) in embryonic articular chondrocytes upregulated Nfat1 expression concomitant with increased H3K4me2 at the Nfat1 promoter. Knockdown of Jmjc-containing histone demethylase-2a (Jhdm2a) in 6-month articular chondrocytes downregulated Nfat1 expression concomitant with increased H3K9me2 at the Nfat1 promoter. These results suggest that Nfat1 is an essential transcriptional regulator of chondrocyte homeostasis in adult articular cartilage. Age-dependent Nfat1 expression in articular chondrocytes is regulated by dynamic histone methylation, one of the epigenetic mechanisms that regulate gene transcription.

Fluorescent nanoparticles of chitosan complex for real-time monitoring drug release

New types of fluorescent nanoparticles (FNPs) were prepared through ionic self-assembly of anthracene derivative and chitosan for applications as drug delivery carriers with real-time monitoring of the process of drug release. Because of the presence of the hydrophilic groups, these FNPs showed excellent dispersion and stability in aqueous solution. The structure and properties of the FNPs were investigated by using means of (1)H NMR, FTIR, SEM, dynamic light scattering (DLS), and so on. The potential practical applications as drug delivery carriers for real-time detection of the drug release process were demonstrated using Nicardipine as a model drug. Upon loading the drug, the strong blue fluorescence of FNPs was quenched due to electron transfer and fluorescence resonance energy transfer (FRET). With release of drug in vitro, the fluorescence was recovered again. The relationship between the accumulative drug release of FNPs and the recovered fluorescence intensity has been established. Such FNPs may open up new perspectives for designing a new class of detection system for monitoring drug release.

Photosensitive nanoparticles of chitosan complex for controlled release of dye molecules

Photosensitive nanoparticles (NPs) were fabricated by employing chitosan hydrochloride (CHC) and photosensitive 4-oxo-4-(pyren-4-ylmethoxy) butanoic acid (PYBA) through ionic self-assembly. Transmission electron microscope (TEM) images showed that the average diameter of the complex NPs depended on the charge molar ratio of PYBA to CHC. The photosensitive properties of the NPs were investigated using (1)H NMR, optical photography, dynamic light scattering and TEM. As a model guest, Nile red dye was loaded in the photosensitive NPs. Under UV light or near infrared laser irradiation, the complex could be dissociated and shrank, so that loaded Nile red was released owing to the decomposition of chemical bonds in the photolabile chromophore groups. The results showed that 70% of the Nile red molecules were released from the NPs under a 1200 mW cm(-2) irradiation of UV light for 50 s. Moreover, the releasing rate of Nile red molecules could be adjusted by altering UV light intensity. Such a chitosan complex has potential applications in the design of photo-controlled guest delivery systems.