Iron-Stimulated N(2) Fixation and Growth in Natural and Cultured Populations of the Planktonic Marine Cyanobacteria Trichodesmium spp

In light of recent proposals that iron (Fe) availability may play an important role in controlling oceanic primary production and nutrient flux, its regulatory impact on N(2) fixation and production dynamics was investigated in the widespread and biogeochemically important diazotrophic, planktonic cyanobacteria Trichodesmium spp. Fe additions, as FeCl(3) and EDTA-chelated FeCl(3), enhanced N(2) fixation (nitrogenase activity), photosynthesis (CO(2) fixation), and growth (chlorophyll a production) in both naturally occurring and cultured (on unenriched oligotrophic seawater) Trichodesmium populations. Maximum enhancement of these processes occurred under FeEDTA-amended conditions. On occasions, EDTA alone led to enhancement. No evidence for previously proposed molybdenum or phosphorus limitation was found. Our findings geographically extend support for Fe limitation of N(2) fixation and primary production to tropical and subtropical oligotrophic ocean waters often characterized by Trichodesmium blooms.

The Treg/Th17 imbalance in patients with idiopathic dilated cardiomyopathy

To assess whether Treg/Th17 balance was broken in patients with idiopathic dilated cardiomyopathy (DCM). We studied 25 patients who were diagnosed as idiopathic DCM (18 men and seven women, mean age 35.6 +/- 5.2) and 25 normal persons (18 men and seven women, mean age 33.8 +/- 4.9). Then, we detected Treg/Th17 functions on different levels including cell frequencies, related cytokine secretion and key transcription factors in patients with idiopathic DCM and controls. The results demonstrated that patients with idiopathic DCM revealed significant increase in peripheral Th17 number, Th17-related cytokines (IL-17, IL-6, IL-23) and transcription factor (RORgammat) levels and obvious decrease in Treg number, Treg-related cytokines (TGF-beta1 and IL-10) and transcription factor (Foxp3) levels when compared to normal persons. Results indicated that Treg/Th17 functional imbalance existed in patients with idiopathic DCM, suggesting a potential role for Treg/Th17 imbalance in the development of idiopathic DCM.

The genetics of NOD-like receptors in Crohn's disease

The first Crohn's disease (CD) susceptibility gene identified was CARD15, which is a member of the emerging NOD-like receptor (NLR) family. These function as intracellular cystosolic pattern recognition receptors (PRRs) and play a central role in the innate immune response. We studied other members of the NLR family using a gene-wide haplotype tagging approach in a well-characterised collection of 547 CD patients and 465 controls. Four single nucleotide polymorphisms (SNPs) in NLRP3 had P values < 0.05 and are in high linkage disequilibrium (LD) with each other (r(2) > 0.90 for all four SNPs). rs4925648 and rs10925019 were the most strongly associated with CD susceptibility (P = 0.001, odds ratio (OR) 1.62, 95% CI 1.2-2.18; and P = 6.5 x 10(-4), OR 1.65, 95% CI 1.23-2.19, respectively). rs1363758 located in NLRP11 was associated with CD susceptibility [P = 0.002 (1.64, 1.19-2.25)], which was weakly confirmed in an independent case-cohort collection on joint analysis [P = 0.05, (1.28, 1-1.64)]. On sub-phenotype analysis, an interesting association between NLRP1 and skin extra-intestinal manifestations and colonic, inflammatory CD was identified. None of these results was replicated in the Wellcome Trust Case Control Consortium study and therefore need replication in a further large cohort.

The allogeneic but not syngeneic dendritic cells effectively generated regulatory T cells from total CD4+ population without exogenous cytokines

Dendritic cells (DC) play a critical role in both the expansion of natural regulatory T cells (nTreg) and conversion of induced Treg (iTreg) from their precursors. In the present study, we evaluated the potential of DC to generate Treg from total CD4(+) population which contains both nTreg and the precursors, and found that allogeneic (allo-DC) but not syngeneic DC (syn-DC) could effectively generated Foxp3(+) Treg from total CD4(+) population in the absence of exogenous cytokines. Compared with freshly purified CD4(+) T cells, allo-DC-stimulated CD4(+) T cells showed increased percentage of CD4(+)CD25(+)Foxp3(+) Treg by 5-7-folds while syn-DC-stimulated CD4(+) T cells did not. Furthermore, we demonstrated that the significant amounts of endogenous IL-2 and TGF-beta, at least partially, contributed to the expansion of nTreg and conversion of iTreg in this cocultural system, respectively. Importantly, similar to nTreg, these allo-DC-generated Treg were capable of suppressing T cell response in vitro. Thus, our research provides a novel and efficient strategy for generation of Treg from total CD4(+) population.

Hepatitis B virus protein preS2 potentially promotes HCC development via its transcriptional activation of hTERT

BACKGROUNDS AND AIMS

Telomerase is significantly reactivated in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). Our previous studies showed that the transactivation unit of HBV surface (S) gene, preS2, could upregulate human telomerase reverse transcriptase (hTERT) expression and telomerase activity of HepG2 cells. Here, we aim to explore the functions, and the underlying mechanisms, of this preS2-mediated hTERT upregulation during HCC development.

METHODS

An antisense blocking assay was performed on HBV-integrated HepG2.2.15 cells. The expression of hTERT was examined in clinical samples to test the role of the preS2-mediated hTERT upregulation in HCC development in vivo. In order to explore the mechanisms of preS2-mediated hTERT upregulation, co-transfection, reporter assays and electrophoretic mobility shift assays (EMSA) were performed.

RESULTS

Blocking preS2 expression reduced hTERT expression, telomerase activity, cell proliferation and tumorigenicity of HepG2.2.15. A region located between -349 and -329 bp upstream of the transcription initiation site of hTERT was identified as responsible for the preS2-mediated effect. preS2 interacted with the preS2-responsible region (PRR) and activated the hTERT promoter. Importantly, hTERT was also highly expressed in preS2-positive human HCC samples. All these findings strongly suggest that preS2 may promote HCC development via hTERT activation.

CONCLUSIONS

HBV protein preS2 upregulates hTERT via the PRR element in promoting HCC development.

Microstructure, nickel suppression and mechanical characteristics of electropolished and photoelectrocatalytically oxidized biomedical nickel titanium shape memory alloy

A new surface modification protocol encompassing an electropolishing pretreatment (EP) and subsequent photoelectrocatalytic oxidation (PEO) has been developed to improve the surface properties of biomedical nickel titanium (NiTi) shape memory alloy (SMA). Electropolishing is a good way to improve the resistance to localized breakdown of NiTi SMA whereas PEO offers the synergistic effects of advanced oxidation and electrochemical oxidation. Our results indicate that PEO leads to the formation of a sturdy titania film on the EP NiTi substrate. There is an Ni-free zone near the top surface and a graded interface between the titania layer and NiTi substrate, which bodes well for both biocompatibility and mechanical stability. In addition, Ni ion release from the NiTi substrate is suppressed, as confirmed by the 10-week immersion test. The modulus and hardness of the modified NiTi surface increase with larger indentation depths, finally reaching plateau values of about 69 and 3.1GPa, respectively, which are slightly higher than those of the NiTi substrate but much lower than those of a dense amorphous titania film. In comparison, after undergoing only EP, the mechanical properties of NiTi exhibit an inverse change with depth. The deformation mechanism is proposed and discussed. Our results indicate that surface modification by dual EP and PEO can notably suppress Ni ion release and improve the biocompatibility of NiTi SMA while the surface mechanical properties are not compromised, making the treated materials suitable for hard tissue replacements.

Prognostic value of different B symptoms in upper aerodigestive tract NK/T-cell lymphoma

e19544

Background: Extranodal NK/T-cell lymphoma (ENKL) is a rare disease originated from NK or toxic T cells. ENKL arising from the upper aerodigestive tract (UNKTL) is a newly recognized subtype and commonly presents with B symptoms. This study is to investigate the prognostic value of different B symptoms in UNKTL. Methods: UNKTL cases with detailed clinical, pathological and prognostic data in our center since 2001 to 2007 were retrospectively analyzed with the major study endpoint of overall survival (OS). Central pathological review was performed. Survival curves were estimated by Kaplan-Meier method and tested by Log Rank method. Statistically significant factors in univariate analysis were then included in multivariate analysis. B symptoms were defined as fever, night sweat and weight loss according to the Ann Arbor Cotswolds meeting. The predictive values of survival for each type of B symptoms were studied independently. Results: 172 cases of UNKTL with a median follow-up duration of 27.4 months were included. 45 ladies and 127 gentlemen had a median age of 43 years. 98 cases were Ann Arbor stage I, 54 were stage II and the remaining 20 cases were stage III or IV. About half of the patients present B symptoms: 82 had fever, 5 had night sweat and 6 present weight loss. Totally 18 patients had ECOG PS larger than 1. The 5-year OS rate of the whole group is 41.8%. Patients with persistent fever before treatment indicated a poor outcome in the univariate analysis (p=.033) and its prognostic value was also confirmed by the Cox regression (p=.030) whereas those of night sweat and weight loss were not (p= .960 and .824 respectively). Conclusions: B symptoms were common in UNKTL patients. Our data suggested that only fever among the three types of B symptoms was independent prognostic factor for UNKTL but it still needs further confirmation.

No significant financial relationships to disclose.

XPS and biocompatibility studies of titania film on anodized NiTi shape memory alloy

A dense titania film is fabricated in situ on NiTi shape memory alloy (SMA) by anodic oxidation in a Na(2)SO(4) electrolyte. The microstructure of the titania film and its influence on the biocompatibility of NiTi SMA are investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), hemolysis analysis, and platelet adhesion test. The results indicate that the titania film has a Ni-free zone near the surface and can effectively block the release of harmful Ni ions from the NiTi substrate in simulated body fluids. Moreover, the wettability, hemolysis resistance, and thromboresistance of the NiTi sample are improved by this anodic oxidation method.

A high-resolution coherent transition radiation diagnostic for laser-produced electron transport studies (invited)

High-resolution images of the rear-surface optical emission from high-intensity (I approximately 10(19) W/cm(2)) laser illuminated metal foils have been recorded using coherent transition radiation (CTR). CTR is generated as relativistic electrons, generated in high-intensity laser-plasma interactions, exit the target's rear surface and move into vacuum. A transition radiation diagnostic (TRD) records time-integrated images in a 24 nm bandwidth window around lambda=529 nm. The optical transmission at lambda=1053 nm, the laser wavelength, is 15 orders of magnitude lower than the transmission at the wavelength of interest, lambda=527 nm. The detector is a scientific grade charge-coupled device (CCD) camera that operates with a signal-to-noise ratio of 10(3) and has a dynamic range of 10(4). The TRD has demonstrated a spatial resolution of 1.4 microm over a 1 mm field of view, limited only by the CCD pixel size.

Application of high-intensity focused ultrasound for the treatment of vascular anomalies: an experimental study in a cockscomb model

OBJECTIVE

We investigated the efficacy and safety of high-intensity focused ultrasound (HIFU) treatment in an animal model of vascular anomalies together with the energy efficiency relationship after varying exposure times and energy levels.

MATERIALS AND METHODS

Hainanhui cockscombs were irradiated using a CZP therapeutic apparatus with an optimal focus over different time periods. The changes in cuticular tissue of the cockscombs and the vascular regions were analyzed by TTC dye, H & E staining, light microscopy, and Doppler ultrasound. The rectal temperatures, weight, water and food consumption of the cocks were also measured during the whole experiment.

RESULTS

H&E staining of the tissues and combs demonstrated similar histological findings, including vessel content, and thickness of the cuticular layers (ds). There were appreciable changes to the cockscombs after doses of 2.6 w x 200 s and 3.6 w x 120 s of HIFU exposure, with 100 % effectiveness and 0.00 % and 37.50 % irreversible damage, respectively. There were no differences with regard to water consumption, weight, rectal temperature and foraging levels monitored pre- and post-HIFU administration of the two doses.

CONCLUSIONS

HIFU exposure is effective in destroying the vascular targeted anomaly with no skin burns, bleeding, large vessel ruptures or other complications. HIFU is feasible, noninvasive and safe for the treatment of vascular anomalies, but clinical trials are necessary.

Synthesis and antifungal activity of 3-substituted thiochromanones

A series of 3-substituted thiochromanones has been prepared. Their structures were confirmed by H(1)-NMR and HRMS. All of the synthesized compounds were screened for antifungal activity against ten fungi species in vitro. The compounds 2f and 2g were more efficient than the control drug, ketoconazole.

[Hypoxia induced HIF-1 accumulation and VEGF expression in gastric epithelial mucosa cell: involvement of ERK1/2 and PI3K/Akt]

Hypoxia is a common environmental stress that influences signaling pathways and cells function, which through initiating intracellular signaling pathways and hence leading to the activation of the transcription factor hypoxia-inducible factor-1 (HIF-1). In this study, we initially confirm that hypoxia activates HIF-1alpha protein expression in a time-dependent manner with a maximum reached at 60 min in vitro and 4h in vivo in gastric mucosa epithelial cells. The expression of HIF-1alpha is correlated with the activation of HIF-1 DNA binding and transcriptional activity. Hypoxia dose not affect HIF-1alpha mRNA transcription but regulates HIF-1alpha protein expression through a translation-dependent pathway to regulate protein synthesis. Hypoxia could induce phosphorylation of Akt, MAPK (ERK), and target of p70S6K1. PI3K and MAPK inhibitor, LY294002 and U0126 could inhibit hypoxia-induced HIF-1 and VEGF expression. We also investigated the role of reactive oxygen species (ROS) involved in HIF-1 and VEGF expression Exogenous addition of H2O2 was sufficient to activate Akt and ERK, scavengers of H2O2 significantly inhibited hypoxia-induced Akt and ERK, and subsequent HIF-lax expression and transcriptional activity. In conclusion, our data suggested that hypoxia- PI3K signaling through Akt and ERK kinases regulated ROS-dependent, hypoxia- induced HIF-1 activation and VEGF expression in gastric mucosa epithelial cells.

Analysis of imazaquin in soybeans by solid-phase extraction and high-performance liquid chromatography

An analytical method for the determination imazaquin residues in soybeans was developed. The developed liquid/liquid partition and strong anion exchange solid-phase extraction procedures provide the effective cleanup, removing the greatest number of sample matrix interferences. By optimizing mobile-phase pH water/acetonitrile conditions with phosphoric acid, using a C-18 reverse-phase chromatographic column and employing ultraviolet detection, excellent peak resolution was achieved. The combined cleanup and chromatographic method steps reported herein were sensitive and reliable for determining the imazaquin residues in soybean samples. This method is characterized by recovery >88.4%, precision <6.7% CV, and sensitivity of 0.005 ppm, in agreement with directives for method validation in residue analysis. Imazaquin residues in soybeans were further confirmed by high performance liquid chromatography-mass spectrometry (LC-MS). The proposed method was successfully applied to the analysis of imazaquin residues in soybean samples grown in an experimental field after treatments of imazaquin formulation.