Exploring the potential of laser desorption ionisation time-of-flight mass spectrometry to analyse organic capping agents on inorganic nanoparticle surfaces.

Analytical techniques are in high demand for the determination of organic capping agents on surfaces of metallic nanoparticles (NPs) such as gold (Au) and silver (Ag). In this study, the potential of laser desorption ionisation time-of-flight mass spectrometry (LDI-ToF-MS) as a technique fit for this purpose is demonstrated. First, a collection of reference spectra of most commonly used organic capping agents, including small molecules and polymers was established. Second, the robustness of the method was tested towards parameters like NP core material and NP size. In a third step, the quantitative capabilities of LDI-ToF-MS were determined. Finally, the potential to detect chemical alterations of the organic capping agent was evaluated. LDI-ToF-MS is able to detect capping agents ranging from small molecules (citric acid, tannic acid, lipoic acid) to large polymers (polyvinylpyrrolidone, branched polyethylenimine and methoxy polyethylene glycol sulfhydryl) on Au and Ag NPs based on characteristic signals for each capping agent. Small molecules showed characteristic fragment ions with low intensities, whereas polymers showed intense signals of the monomeric subunit. The NP concentration range comprises about two orders of magnitude with lowest detection limits of 5 mg/L or a capping agent concentration in the lower nM range. Changes in capping agent composition are detectable at NP concentrations in the g/L range. Thus, LDI-ToF-MS is particularly suitable for characterisation of polymer-capped NPs with high NP concentrations. This may be the case for quality control as part of the material synthesis and testing. Graphical abstract.

Clinical and molecular genetic findings in autosomal dominant OPA3-related optic neuropathy.

Leber hereditary optic neuropathy and autosomal dominant optic atrophy are the two most common inherited optic neuropathies. The latter has been associated with mutations in the OPA1 and OPA3 genes. To date, only six families with OPA3-associated dominant optic atrophy have been reported. In order to identify additional families, we performed Sanger sequencing of the OPA3 gene in 75 unrelated optic neuropathy patients. Affected individuals from two families were found to harbour the c.313C > G, p.(Gln105Glu) change in heterozygous state; this genetic defect has been previously reported in four dominant optic atrophy families. Intra- and interfamilial variability in age of onset and presenting symptoms was observed. Although dominant OPA3 mutations are typically associated with optic atrophy and cataracts, the former can be observed in isolation; we report a case with no lens opacities at age 38. Conversely, it is important to consider OPA3-related disease in individuals with bilateral infantile-onset cataracts and to assess optic nerve health in those whose vision fail to improve following lens surgery. The papillomacular bundle is primarily affected and vision is typically worse than 20/40. Notably, we describe one subject who retained normal acuities into the fifth decade of life. The condition can be associated with extraocular clinical features: two affected individuals in the present study had sensorineural hearing loss. The clinical heterogeneity observed in the individuals reported here (all having the same genetic defect in OPA3) suggests that the molecular pathology of the disorder is likely to be complex.

Leukemic priming of resting NK cells is killer Ig-like receptor independent but requires CD15-mediated CD2 ligation and natural cytotoxicity receptors.

Resting human NK cells require a two-stage activation process that we have previously described as "priming" and "triggering." NK-sensitive tumor cells provide both priming and triggering signals. NK-resistant tumors evade lysis, mostly by failure to prime; however, we recently reported a tumor cell line (CTV-1) that primes resting NK cells but fails to trigger lysis. In this article, we report two additional leukemia cell lines that prime NK cells but are resistant to lysis. Tumor-mediated NK priming is via CD2 binding to a ligand within CD15 on the tumor cell. NK-resistant RAJI cells became susceptible to NK lysis following transfection and expression of CD15. Blockade of CD15 on K562 cells or on CD15(+) RAJI cells significantly inhibited lysis, as did blockade of CD2 on resting NK cells. NK priming via CD2 induced CD16 shedding, releasing CD3ζ to the CD2, leading to its phosphorylation and the subsequent phosphorylation of linker for activation of T cells and STAT-5 and synthesis of IFN-γ. Blockade of C-type lectin receptors significantly suppressed the tumor-mediated priming of NK cells, whereas blockade of Ig-superfamily-like receptors had no effect at the NK-priming stage. Tumor priming of resting NK cells was irrespective of HLA expression, and blockade of HLA-killer Ig-like receptor interactions did not influence the incidence or degree of priming. However, CD15-CD2 interactions were critical for NK priming and were required, even in the absence of HLA-mediated NK inhibition. Tumor-mediated priming led to a sustained primed state, and the activated NK cells retained the ability to lyse NK-resistant tumors, even after cryopreservation.

Associations of ARMS2 and NR3C2 genes polymorphisms with central serous chorioretinopathy in a Greek population.

BACKGROUND: Central serous chorioretinopathy (CSCR) is characterized by serous detachment of the central neurosensory retina and it is one of the most common retinal disorders. Various genetic polymorphisms have been associated with CSCR development. METHODS: The aim of our study was to investigate the potential association between ARMS2 (rs10490924) and NR3C2 (rs2070951 and rs5522) genes polymorphisms and CSCR development in a well defined Greek cohort for the first time in literature. We enrolled, in our case-control study, 48 CSCR patients and 137 controls. The ARMS2 (rs10490924) and NR3C2 (rs2070951 and rs5522) genes polymorphisms were analyzed using Polymerase Chain Reaction (PCR) assays. RESULTS: In our study, we found significant associations between ARMS2rs10490924 and NR3C2rs2070951 single nucleotide polymorphisms and CSCR development. Specifically, the GTrs10490924 genotype frequency of the ARMS2 gene was found to be significantly associated with risk of CSCR and T allele of rs10490924ARMS2 gene was also found to increase risk for CSCR. The genotype frequency GC and CC of rs2070951NR3C2 gene were observed more frequently in CSCR patients than controls and C allele of rs2070951NR3C2 gene was also observed more frequently in CSCR patients than controls. Rs5522 of NR3C2 gene polymorphism was not found to be significantly associated with CSCR. CONCLUSION: Our findings showed, for the first time in a Greek population, that SNPs in the ARMS2 and NR3C2 genes are significantly associated with risk of CSCR. The results of this study support the involvement of extracellular matrix (ARMS2 gene) and mineralocorticoid receptor (MR) in the pathogenesis of CSCR.

The Genetic Background of Central Serous Chorioretinopathy: A Review on Central Serous Chorioretinopathy Genes.

Central serous chorioretinopathy is characterized by neurosensory detachment of the central retina secondary to fluid leakage through the retinal pigment epithelium. Though it has an incidence of 9,9 per 100.000 in men and 1,7 per 100.000 in women, it is the fourth most common retinal disorder. Central serous chorioretinopathy patients present with blurred vision, central scotoma, metamorphopsia, micropsia and mild color discrimination. It is usually a self-limited disorder with nearly none or minimal visual impairment but in some patients the disease persists and may cause severe visual impairment. Central serous chorioretinopathy pathophysiology is not well understood. Choroid, retinal pigment epithelium and hormonal pathways seem to play important roles in central serous chorioretinopathy pathophysiology. Also, familial cases of the disease indicate that there is a genetic background. The identification of certain disease genes could lead to the development of better diagnostic and therapeutic approaches for central serous chorioretinopathy patients.

Micro magnetofluidics: droplet manipulation of double emulsions based on paramagnetic ionic liquids.

The ability to control and manipulate discrete fluid droplets by magnetic fields offers new opportunities in microfluidics. A surfactant-free and easy to realize technique for the continuous generation of double emulsion droplets, composed of an organic solvent and a paramagnetic ionic liquid, is applied. The inner phase of the emulsion droplet consists of imidazolium-based ionic liquids with either iron, manganese, nickel or dysprosium containing anions which provide paramagnetic behaviour. The double emulsion droplets are dispersed in a continuous phase of FC-40. All substances - the organic phase, the paramagnetic ionic liquid and the continuous phase -are immiscible. The magnetic properties of ionic liquids allow, through the influence of external magnetic fields, the manipulation of individual emulsion droplets such as capture and release, rotation and distortion. Arrays of magnets allow a coalescence of emulsion droplets and their subsequent mixing by flowing through an alternating permanent magnetic field. In addition, the double emulsion droplets can be split and reunified, or continuously separated into their original phases.

Effect of a fixed brimonidine-timolol combination on intraocular pressure after phacoemulsification.

PURPOSE: To evaluate the effect of a fixed combination of brimonidine-timolol on intraocular pressure (IOP) after phacoemulsification cataract surgery. SETTING: Department of Ophthalmology, Patras University Hospital, Patras, Greece. DESIGN: Prospective randomized comparative case series. METHODS: Patients scheduled for phacoemulsification were randomly assigned to 1 of 2 groups. The treatment group received 1 drop of brimonidine-timolol fixed combination immediately after surgery, and the control group received no treatment. The IOP was measured preoperatively and 6, 12, and 24 hours postoperatively. RESULTS: The treatment group comprised 28 eyes and the control group, 30 eyes. The mean IOP increased by 0.14 mm Hg ± 3.88 (SD) (P = .88) in the treatment group and increased by 2.8 ± 5.01 mm Hg (P = .007) in the control group. Twelve hours after surgery, the mean IOP decreased by -0.57 ± 3.82 mm Hg (P = .49) in the treatment group and increased by 2.20 ± 4.56 mm Hg (P = .009) in the control group. Twenty-four hours after surgery, the mean IOP decreased by -1.57 ± 2.30 mm Hg (P=.012) in the treatment group and increased by 0.86 ± 4.21 mm Hg (P = .175) in the control group. The mean IOP change between the 2 study groups 6, 12, and 24 hours postoperatively was statistically significantly different (P = .015, P = .006, and P = .003; respectively). CONCLUSION: The fixed brimonidine-timolol combination effectively reduced IOP 6, 12, and 24 hours after phacoemulsification cataract surgery.

Antibodies to peripheral nerve myelin proteins in chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired disorder of the peripheral nervous system with a probable auto-immune pathogenesis. The nature of the responsible autoantigens is unclear in most patients. We used the Western immunoblot technique to seek antibodies to peripheral nerve protein antigens. Sera from eight of 32 (25%) CIDP patients, 12 of 37 (32%) Guillain-Barré syndrome (GBS) patients, zero of 30 (0%) chronic idiopathic axonal polyneuropathy patients and two of 39 (5%) healthy control subjects contained anti-peripheral nerve protein antibodies. The frequency of such antibodies was significantly greater in both CIDP (p = 0.04) and GBS (p = 0.003) patients than in normal control subjects. For CIDP patients, there were non-significant trends for antibodies to be more common in females and in those who responded to treatment with either intravenous immunoglobulin or plasma exchange. The commonest antibodies were directed against a band at 28 kDa, resembling that labelled by a monoclonal antibody against myelin protein zero (P0). Six CIDP and seven GBS patients' sera reacted with this band. These results support the view that antibodies to myelin proteins, and especially P0, are present in the serum of some patients with CIDP and GBS.

Inhibition of intravascular thrombosis in murine endotoxemia by targeted expression of hirudin and tissue factor pathway inhibitor analogs to activated endothelium.

We have generated transgenic mice expressing the leech anticoagulant hirudin and human tissue factor pathway inhibitor tethered to the cell surface by fusion with fragments of human CD4 and P-selectin. Expression of the transgenes is under the control of the CD31 (platelet endothelial cell adhesion molecule [PECAM]) promoter, limiting expression to endothelial cells, monocytes, and platelets. In addition, the P-selectin sequence directs expression to secretory granules. Functional cell surface expression only occurs when the cells are activated. In a mouse model of systemic lipopolysaccharide (LPS)-induced endotoxemia, we show that expression of either anticoagulant on activated endothelium inhibits the widespread intravascular thrombosis, thrombocytopenia, and consumptive coagulopathy associated with endotoxemia. Importantly, non- LPS-treated transgenic mice had normal baseline bleeding times. We speculate that targeted delivery of anticoagulants to the endothelium may be a strategy worth pursuing in clinical sepsis to improve efficacy of systemic anticoagulation while minimizing potential hemorrhagic side effects.