Polydopamine–polyethylene glycol–albumin antifouling coatings on multiple substrates

Polydopamine–PEG coatings on different substrates: effects of PDA layer properties on PEG grafting and anti-biofouling properties.

Real-Space Imaging of the Tailored Plasmons in Twisted Bilayer Graphene

We report a systematic plasmonic study of twisted bilayer graphene (TBLG)-two graphene layers stacked with a twist angle. Through real-space nanoimaging of TBLG single crystals with a wide distribution of twist angles, we find that TBLG supports confined infrared plasmons that are sensitively dependent on the twist angle. At small twist angles, TBLG has a plasmon wavelength comparable to that of single-layer graphene. At larger twist angles, the plasmon wavelength of TBLG increases significantly with apparently lower damping. Further analysis and modeling indicate that the observed twist-angle dependence of TBLG plasmons in the Dirac linear regime is mainly due to the Fermi-velocity renormalization, a direct consequence of interlayer electronic coupling. Our work unveils the tailored plasmonic characteristics of TBLG and deepens our understanding of the intriguing nano-optical physics in novel van der Waals coupled two-dimensional materials.

Imaging the Localized Plasmon Resonance Modes in Graphene Nanoribbons

We report a nanoinfrared (IR) imaging study of the localized plasmon resonance modes of graphene nanoribbons (GNRs) using a scattering-type scanning near-field optical microscope (s-SNOM). By comparing the imaging data of GNRs that are aligned parallel and perpendicular to the in-plane component of the excitation laser field, we observed symmetric and asymmetric plasmonic interference fringes, respectively. Theoretical analysis indicates that the asymmetric fringes are formed due to the interplay between the localized surface plasmon resonance (SPR) mode excited by the GNRs and the propagative surface plasmon polariton (SPP) mode launched by the s-SNOM tip. With rigorous simulations, we reproduce the observed fringe patterns and address quantitatively the role of the s-SNOM tip on both the SPR and SPP modes. Furthermore, we have seen real-space signatures of both the dipole and higher-order SPR modes by varying the ribbon width.

Isolation, identification and fibrolytic characteristics of rumen fungi grown with indigenous methanogen from yaks (Bos grunniens) grazing on the Qinghai-Tibetan Plateau

AIM

To obtain co-cultures of anaerobic fungi and their indigenously associated methanogens from the rumen of yaks grazing on the Qinghai-Tibetan Plateau and investigate their morphology features and ability to degrade lignocellulose.

METHODS AND RESULTS

Twenty fungus-methanogen co-cultures were obtained by Hungate roll-tube technique. The fungi were identified as Orpinomyces, Neocallimastix and Piromyces genera based on the morphological characteristics and internal transcribed spacer 1 sequences analysis. All methanogens were identified as Methanobrevibacter sp. by 16S rRNA gene sequencing. There were four types of co-cultures: Neocallimastix with Methanobrevibacter ruminantium, Orpinomyces with M. ruminantium, Orpinomyces with Methanobrevibacter millerae and Piromyces with M. ruminantium among 20 co-cultures. In vitro studies with wheat straw as substrate showed that the Neocallimastix with M. ruminantium co-cultures and Piromyces with M. ruminantium co-cultures exhibited higher xylanase, filter paper cellulase (FPase), ferulic acid esterase, acetyl esterase activities, in vitro dry matter digestibility, gas, CH4 , acetate production, ferulic acid and p-coumaric acid releases. The Neocallimastix frontalis Yak16 with M. ruminantium co-culture presented the strongest lignocellulose degradation ability among 20 co-cultures.

CONCLUSIONS

Twenty fungus-methanogen co-cultures were obtained from the rumen of grazing yaks. The N. frontalis with M. ruminantium co-cultures were highly effective combination for developing a fermentative system that bioconverts lignocellulose to high activity fibre-degrading enzyme, CH4 and acetate.

SIGNIFICANCE AND IMPACT OF THE STUDY

The N. frontalis with M. ruminantium co-cultures from yaks grazing on the Qinghai-Tibetan Plateau present great potential in lignocellulose biodegradation industry.

[Management of early bronchopleural fistula after pneumonectomy]

OBJECTIVE

To investigate the management of early bronchopleural fistula(BPF) within one month after pneumonectomy.

METHODS

A total of 30 cases developed BPF within one month after pneumonectomy in recent 30 years were reviewed from First Hospital of Jilin University. All patients were treated by reoperation, closed drainage with or without open thoracic window, or endobronchial glue.

RESULTS

Seventeen patients were returned to the operating room for reclosure of BPF, one patients died of BPF and 16 reoperations were successful.Twelve cases were treated by closed drainage with or without followed open thoracic window. In 6 patients who were managed by closed drainage alone, 2 cases died of BPF and 4 bronchopleural fistulas closed spontaneously. In 6 patients treated with closed drainage and later with open thoracic window, one case died of BPF. One patient successfully underwent endoscopic glue to close BPF with injection three times.

CONCLUSION

Within one month postoperatively, BPF without established empyema with pus should be reoperated if the patient had enough cardiopulmonary reserve and could there fore tolerate reoperation. Contamination of pleural space is not the contraindication to reoperation. Reclosure via original thoracotomy and repair the fistula with pedicled intercostal muscle flap are convenient and efficient. Drainage with or without followed open thoracic window is appropriate for the patients with limited cardiopulmonary reserve, impaired general condition, secondary to empyema with pus, early recurred cancer, or some small fistulas.

Direct molecular typing of Bordetella pertussis from nasopharyngeal specimens in China in 2012-2013

Data on the molecular epidemiology of Bordetella pertussis are limited in developing countries where whole-cell pertussis vaccines (WCVs) have been used. The aim of this study was to determine the genotypes of circulating B. pertussis in China by direct molecular typing of clinical specimens. DNA extracts of 122 nasopharyngeal swabs (NPs) positive for B. pertussis by polymerase chain reaction (PCR) (targeting IS481 and ptx-Pr) from 2012 to 2013 were used for typing using the multiple-locus variable number tandem repeat analysis (MLVA) and also by PCR-based multilocus sequence typing (MLST) of B. pertussis virulence genes (ptxP, prn, and fim3). One hundred and eight DNA extracts (89 %) generated a complete MLVA type (MT). Among the 18 MTs obtained, MT55 (52 %) and MT104 (13 %) were the most common. MT27, which is linked to the ptxP3 allele and is prevalent in many developed countries using acellular pertussis vaccines (ACVs), was only found in 7 (6 %) DNA extracts. Eighty-seven DNA extracts (71 %) produced a complete multiantigen sequence typing (MAST) type. Of them, 77 (89 %) had the ptxP1/prn1/fim3-1 allele profile. Four DNA extracts (5 %) had the ptxP3/prn2/fim3-2 profile and 3 (4 %) had the ptxP3/prn1/fim3-2 allele profile. These seven DNA extracts also harbored MT27. Our result shows that B. pertussis circulating in China was different from those found in countries where ACVs have been in use, supporting the notion that selection pressure induced by WCVs and ACVs on the bacterial population differs.

PAR1-stimulated platelet releasate promotes angiogenic activities of endothelial progenitor cells more potently than PAR4-stimulated platelet releasate

BACKGROUND

Endothelial progenitor cells (EPCs) are important for endothelial regeneration and angiogenesis. Thrombin protease-activated receptor 1 (PAR1) PAR1 and PAR4 stimulation induces selective release of platelet proangiogenic and antiangiogenic regulators.

OBJECTIVE

To investigate if PAR1-stimulated platelet releasate (PAR1-PR) and PAR4-PR regulate angiogenic properties of EPCs in different manners.

METHODS AND RESULTS

EPCs were generated from peripheral mononuclear cell culture. Washed platelets (2 × 10(9) mL(-1)) were stimulated by PAR1-activating peptide (PAR1-AP; 10 μmol L(-1)) or PAR4-AP (100 μmol L(-1)) to prepare PAR1-PR and PAR4-PR, respectively. PAR1-PR or PAR4-PR had little influence on EPC proliferation. EPC migration experiments using a modified Boyden chamber showed that both platelet releasates facilitated EPC migration. As for in vitro tube formation on Matrigel, PAR1-PR and PAR4-PR similarly enhanced capillary-like network formation of EPCs in the complete EPC medium containing 10% FBS and a cocktail of growth factors, while PAR1-PR more profoundly increased EPC tube formation in basal culture medium supplemented with only 0.5% FBS than did PAR4-PR. The latter was confirmed in the murine angiogenesis model of subcutaneous Matrigel implantation. Moreover, blockade of vascular endothelial growth factor, stromal cell-derived factor 1α, or matrix metalloproteinases attenuated EPC migration and tube formation, suggesting a cooperation of these factors in the enhancements.

CONCLUSIONS

PAR1-PR enhances vasculogenesis more potently than PAR4-PR, and the enhancements require a cooperation of multiple platelet-derived angiogenic regulators.

Novel NPHS1 splice site mutations in a Chinese child with congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS) is defined as heavy proteinuria or nephrotic syndrome occurring before 3 months of age. It is characterized by early onset and progresses to end-stage renal disease. Recently, several genes associated with CNS have been identified, including NPHS1 and NPHS2. Mutations in the NPHS1 gene have been identified in patients with CNS in Finland with relatively high frequency. Thus far, only a few case reports about CNS have described an NPHS1 mutation in China. In this study, mutational analyses of NPHS1 and NPHS2 were performed in a Chinese child with CNS. Mutations were analyzed in all exons and exon/intron boundaries of NPHS1 and NPHS2 in the patient and his parents as well as in 50 unrelated controls using polymerase chain reaction and direct sequencing techniques. No mutations were detected in NPHS2. A novel splice site mutation (IVS11+1G>A) within intron 11 and a missense mutation within exon 8 (c.928G>A) in the NPHS1 gene were detected in the child. The child's mother had normal urinalysis and a c.928G>A (D310N) heterozygous mutation, and his father had normal urinalysis and IVS11+1G>A. These were not identified in the 50 unrelated controls. The novel splice site mutation of IVS11+1G>A and a missense mutation at c.928G>A in NPHS1 were found to cause CNS in this Chinese child.

Monocytic myeloid-derived suppressor cells accumulate in renal transplant patients and mediate CD4(+) Foxp3(+) Treg expansion

Myeloid-derived suppressor cells (MDSC) are negative regulators of the immune response and are in part responsible for the inhibition of the T cell-mediated immune responses. While MDSC have been demonstrated to participate in the induction of prolonged allograft survival in animal models of transplantation, little is known about their immune regulatory function in human transplant recipients. Here, we report that two subsets of human MDSC expressing CD11b(+), CD33(+) and HLA-DR(-) develop in renal patients posttransplantation. We found that CD14(+) expressing monocytic MDSC isolated from transplant recipients were highly efficient in suppressing the proliferation of CD4(+) T cells in mixed leukocyte reactions. In addition, we observed that CD11b(+) CD33(+) HLA-DR(-) MDSC are capable of expanding Treg in vitro, and their accumulation overtime after transplantation linearly correlated with an increase in Treg in vivo. This is the first study to link the presence of MDSC with the emergence of Treg in vivo in transplant recipients, and to define the subpopulation of MDSC derived from transplant recipients responsible for generation of Treg. Further studies are necessary to determine the alloimmune regulatory function of MDSC in human transplant recipients.

Functionalized mesoporous silica particles for application in drug delivery system

In these years, ordered mesoporous silica materials have shown promising applications in drug delivery system as drug carriers. These carriers with stable mesoporous structure, large surface area, good biocompatibility and tailored size of mesopores exhibit significant property of higher drug loading. However, silica-based mesoporous materials cannot control the release of the loaded drug without modifications. In this paper, we review the recent research work discussing functionalization of mesoporous materials by various components and methods for application in drug delivery systems. All the examples show that these functionalized mesoporous silica-based systems have great potential for a variety of drug delivery applications, specifically in the fields of the drug targeted and controlled delivery systems.

Potential role of soluble B7-H3 in liver immunopathogenesis during chronic HBV infection

Immune-mediated mechanisms have been implicated in liver pathogenesis and subsequent progression in hepatitis B virus (HBV) infection. Costimulatory molecules, the important regulators of immune responses, participate in the regulation of liver pathology in HBV infection. However, the role of B7-H3 (CD276, a new member of B7 family) in this process has not been investigated. In this study, we detected abundant soluble B7-H3 (sB7-H3) in the plasma of patients with chronic HBV infections. The increase of the plasma B7-H3 was associated with the progression of liver cirrhosis and accompanied by decreased expression of B7-H3 on hepatocytes. The identification analysis suggests that the plasma B7-H3 might be derived from the membrane-bound B7-H3 on hepatocytes. A functional study showed that immobilized (4Ig) B7-H3Ig fusion protein could inhibit TCR-induced proliferation and IFN-γ secretion of T cells, which could be partially blocked by soluble B7-H3flag fusion protein. These results suggest that the reduced expression of B7-H3 in the livers might temper the inhibition of T-cell responses mediated by B7-H3 expressed on hepatocytes and thus promote the hepatic inflammation and hepatitis progression in the chronic HBV-infected patients.

Immune reconstitution following rabbit antithymocyte globulin

Depletional induction therapies are routinely used to prevent acute rejection and improve transplant outcome. The effects of depleting agents on T-cell subsets and subsequent T-cell reconstitution are incompletely defined. We used flow cytometry to examine the effects of rabbit antithymocyte globulin (rATG) on the peripheral T-cell repertoire of pediatric and adult renal transplant recipients. We found that while rATG effectively depleted CD45RA+CD27+ naïve and CD45RO+CD27+ central memory CD4+ T cells, it had little effect on CD45RO+CD27- CD4+ effector memory or CD45RA+CD31-, CD45RO+CD27+ and CD45RO+CD27- CD8+ T cell subsets. When we performed a kinetic analysis of CD31+ recent thymic emigrants and CD45RA+/RO+ T cells, we found evidence for both thymopoiesis and homeostatic proliferation contributing to immune reconstitution. We additionally examined the impact of rATG on peripheral CD4+Foxp3+ T cells. We found that in adults, administration of rATG-induced peripheral expansion and new thymic emigration of T cells with a Treg phenotype, while CD4+Foxp3+ T cells of thymic origin predominated in children, providing the first evidence that rATG induces Treg in vivo. Collectively our data indicate that rATG alters the balance of regulatory to memory effector T cells posttransplant, providing an explanation for how it positively impacts transplant outcome.

Prioritisation of associations between protein domains and complex diseases using domain-domain interaction networks

It is of vital importance to find genetic variants that underlie human complex diseases and locate genes that are responsible for these diseases. Since proteins are typically composed of several structural domains, it is reasonable to assume that harmful genetic variants may alter structures of protein domains, affect functions of proteins and eventually cause disorders. With this understanding, the authors explore the possibility of recovering associations between protein domains and complex diseases. The authors define associations between protein domains and disease families on the basis of associations between non-synonymous single nucleotide polymorphisms (nsSNPs) and complex diseases, similarities between diseases, and relations between proteins and domains. Based on a domain-domain interaction network, the authors propose a 'guilt-by-proximity' principle to rank candidate domains according to their average distance to a set of seed domains in the domain-domain interaction network. The authors validate the method through large-scale cross-validation experiments on simulated linkage intervals, random controls and the whole genome. Results show that areas under receiver operating characteristic curves (AUC scores) can be as high as 77.90%, and the mean rank ratios can be as low as 21.82%. The authors further offer a freely accessible web interface for a genome-wide landscape of associations between domains and disease families.

Regulation of chondrocyte differentiation by ADAMTS-12 metalloproteinase depends on its enzymatic activity

ADAMTS-12, a metalloproteinase that belongs to ADAMTS family, is strongly upregulated during chondrogenesis and demonstrates prominent expression in the growth plate chondrocytes. ADAMTS-12 potently inhibits chondrocyte differentiation, as revealed by altered expression of both early and later genes critical for chondrogenesis. In addition, ADAMTS-12-mediated inhibition of chondrogenesis depends on its enzymatic activity, since its point mutant lacking enzymatic activity completely loses this activity. Furthermore, the C-terminal four thrombospondin motifs known to bind COMP substrate is necessary for its full proteolytic activity and inhibition of chondrocyte differentiation. Mechanism studies demonstrate that ADAMTS-12 induces PTHrP, whereas it inhibits IHH during chondrogenesis. Furthermore, PTHrP induces ADAMTS-12 and ADAMTS-12 is hardly detectable in PTHrP-/-growth plate chondrocytes. Importantly, knocking down ADAMTS-12 mRNA levels or blocking ADAMTS-12 activity almost abolishes the PTHrP-mediated inhibition of type X collagen expression. Collectively, these findings demonstrate that ADAMTS-12, a downstream molecule of PTHrP signaling, is a novel regulator of chondrogenesis.

Inhibition of ADAMTS-7 and ADAMTS-12 degradation of cartilage oligomeric matrix protein by alpha-2-macroglobulin

OBJECTIVE

As we previously reported, ADAMTS-7 and ADAMTS-12, two members of ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family, degrade cartilage oligomeric matrix protein (COMP) in vitro and are significantly induced in the cartilage and synovium of arthritic patients [Liu CJ, Kong W, Ilalov K, Yu S, Xu K, Prazak L, et al. ADAMTS-7: a metalloproteinase that directly binds to and degrades cartilage oligomeric matrix protein. FASEB J 2006;20(7):988-90; Liu CJ, Kong W, Xu K, Luan Y, Ilalov K, Sehgal B, et al. ADAMTS-12 associates with and degrades cartilage oligomeric matrix protein. J Biol Chem 2006;281(23):15800-8]. The purpose of this study was to determine (1) whether cleavage activity of ADAMTS-7 and ADAMTS-12 of COMP are associated with COMP degradation in osteoarthritis (OA); (2) whether alpha-2-macroglobulin (a(2)M) is a novel substrate for ADAMTS-7 and ADAMTS-12; and (3) whether a(2)M inhibits ADAMTS-7 or ADAMTS-12 cleavage of COMP.

METHODS

An in vitro digestion assay was used to examine the degradation of COMP by ADAMTS-7 and ADAMTS-12 in the cartilage of OA patients; in cartilage explants incubated with tumor necrosis factor-alpha (TNF-alpha) or interleukin-1-beta (IL-1beta) with or without blocking antibodies; and in human chondrocytes treated with specific small interfering RNA (siRNA) to knockdown ADAMTS-7 or/and ADAMTS-12. Digestion of a(2)M by ADAMTS-7 and ADAMTS-12 in vitro and the inhibition of ADAMTS-7 or ADAMTS-12-mediated digestion of COMP by a(2)M were also analyzed.

RESULTS

The molecular mass of the COMP fragments produced by either ADAMTS-7 or ADAMTS-12 were similar to those observed in OA patients. Specific blocking antibodies against ADAMTS-7 and ADAMTS-12 dramatically inhibited TNF-alpha- or IL-1beta-induced COMP degradation in the cultured cartilage explants. The suppression of ADAMTS-7 or ADAMTS-12 expression by siRNA silencing in the human chondrocytes also prevented TNF-alpha- or IL-1beta-induced COMP degradation. Both ADAMTS-7 and ADAMTS-12 were able to cleave a(2)M, giving rise to 180- and 105-kDa cleavage products, respectively. Furthermore, a(2)M inhibited both ADAMTS-7- and ADAMTS-12-mediated COMP degradation in a concentration (or dose)-dependent manner.

CONCLUSION

Our observations demonstrate the importance of COMP degradation by ADAMTS-7 and ADAMTS-12 in vivo. Furthermore, a(2)M is a novel substrate for ADAMTS-7 and ADAMTS-12. More significantly, a(2)M represents the first endogenous inhibitor of ADAMTS-7 and ADAMTS-12.

Transient binding and dissipation in cross-linked actin networks

In contrast with entangled actin solutions, transiently cross-linked actin networks can provide highly elastic properties while still allowing for local rearrangements in the microstructure-on biological relevant time scales. Here, we show that thermal unbinding of transient cross-links entails local stress relaxation and energy dissipation in an intermediate elasticity dominated frequency regime. We quantify the viscoelastic response of an isotropically cross-linked actin network by experimentally tuning the off rate of the transiently cross-linking molecules, their density, and the solvent viscosity. We reproduce the measured frequency response by a semiphenomenological model that is predicated on microscopic unbinding events.

The relationship between endothelial dysfunction and oxidative stress in diabetes and prediabetes

OBJECTIVE

Diabetes mellitus is associated with endothelial dysfunction and oxidative stress (OS). The aim of the present study was to determine whether increased OS and impaired endothelial function, are present in early states of diabetes, such as impaired glucose tolerance (IGT) and impaired fasting glucose (IFG).

METHODS

Brachial artery flow-mediated dilatation (FMD) and nitrate-induced dilatation were measured in 133 subjects with carbohydrate abnormalities (45 IGT, 44 IFG and 44 Type 2 diabetes mellitus) and in 46 subjects with normal glucose tolerance (NGT). Waist circumference, body mass index, blood pressure and fasting lipid profiles were obtained, and glucose and insulin values in response to a 75-g oral glucose load were also measured. Plasma malondialdehyde (MDA) and superoxide dismutase (SOD) activity were determined.

RESULTS

Patients with diabetes and prediabetes had a higher plasma MDA concentration, but a lower plasma SOD activity than the NGT group (p = 0.006) and SOD activity was positively associated with FMD (p = 0.039). FMD were significantly reduced in the groups of subjects with abnormal carbohydrate metabolism compared with the NGT group (p = 0.035). Among the subjects with diabetes and prediabetes, FMD showed a negative correlation with fasting glucose and/or plasma glucose level at 120 min after oral glucose tolerance test (p = 0.028).

CONCLUSIONS

The results showed that endothelial dysfunction and increased OS were present in subjects with IGT and IFG, indicating endothelial damage in these stages.

Model-based methods for identifying periodically expressed genes based on time course microarray gene expression data

MOTIVATION

The expressions of many genes associated with certain periodic biological and cell cycle processes such as circadian rhythm regulation are known to be rhythmic. Identification of the genes whose time course expressions are synchronized to certain periodic biological process may help to elucidate the molecular basis of many diseases, and these gene products may in turn represent drug targets relevant to those diseases.

RESULTS

We propose in this paper a statistical framework based on a shape-invariant model together with a false discovery rate (FDR) procedure for identifying periodically expressed genes based on microarray time-course gene expression data and a set of known periodically expressed guide genes. We applied the proposed methods to the alpha-factor, cdc15 and cdc28 synchronized yeast cell cycle data sets and identified a total of 1010 cell-cycle-regulated genes at a FDR of 0.5% in at least one of the three data sets analyzed, including 89 (86%) of 104 known periodic transcripts. We also identified 344 and 201 circadian rhythmic genes in vivo in mouse heart and liver tissues with FDR of 10 and 2.5%, respectively. Our results also indicate that the shape-invariant model fits the data well and provides estimate of the common shape function and the relative phases for these periodically regulated genes.

Quantitative determination of nitrendipine and its metabolite dehydronitrendipine in human plasma using liquid chromatography-tandem mass spectrometry

A sensitive and high-throughput LC-MS-MS method was developed for simultaneous determination of nitrendipine (NIT) and its major metabolite, dehydronitrendipine (DNIT) in human plasma using nifedipine as the internal standard. Plasma samples were prepared based on a simple liquid-liquid extraction. The extracted samples were analyzed on a Zorbax SB C(18) column interfaced with a triple quadrupole tandem mass spectrometer. Positive atmospheric pressure chemical ionization was employed as the ionization source. The analytes were detected by use of selected reaction monitoring mode. Standard curves were linear (r > or = 0.995) over the concentration range of 0.4-40 ng/mL for NIT and 0.2-20 ng/mL for DNIT. The intra- and inter-run precision was measured to be below 8.5% for NIT and DNIT. The inter-run accuracy was less than 4% for the analytes. The overall extraction recoveries of NIT and DNIT were determined to be about 75% and 78% on average, respectively. The chromatographic run time was approximately 3 min. More than 120 samples could be assayed daily with this method, including sample preparation, data acquisition and processing. The method developed was successfully used to investigate plasma concentrations of NIT and DNIT in a pharmacokinetic study of volunteers who received NIT orally.