TRPC1 regulates fMLP-stimulated migration and chemotaxis of neutrophil granulocytes.

Neutrophils form the first line of defense of the innate immune system and are rapidly recruited by chemotactic signals to sites of inflammation. Understanding the mechanisms of neutrophil chemotaxis is therefore of great interest for the potential development of new immunoregulatory therapies. It has been shown that members of the transient receptor potential (TRP) family of cation channels are involved in both cell migration and chemotaxis. In this study, we demonstrate that TRPC1 channels play an important role in fMLP mediated chemotaxis and migration of murine neutrophils. The knock-out of TRPC1 channels leads to an impaired migration, transmigration and chemotaxis of the neutrophils. In contrast, Ca²âº influx but not store release after activation of the TRPC1(-/-) neutrophils with fMLP is strongly enhanced. We show that the enhanced Ca²âº influx in the TRPC1(-/-) neutrophils is associated with a steepened front to rear gradient of the intracellular Ca²âº concentration with higher levels at the cell rear. Taken together, this paper highlights a distinct role of TRPC1 in neutrophil migration and chemotaxis. We propose that TRPC1 controls the activity of further Ca²âº influx channels and thus regulates the maintenance of intracellular Ca²âº gradients which are critical for cell migration. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

A review of the efficacy, safety and tolerability of Lacrycon® eye drops for the treatment of dry eye syndrome.

Lacrycon® is a preservative-free hypotonic artificial tear for the treatment of dry eye syndrome containing hyaluronic acid, carbomer, and glycerol. Lacrycon has been used for many years; this is the first comprehensive review of clinical efficacy and tolerability. Eight clinical studies (1992-2013) were reviewed. Comparators included phosphate-buffered saline (Phase I) and active controls (Phase II: Lacrisol™; Phase III: Gel-larmes™, Lacrisol, Hyalistil®, Vismed®, or the currently prescribed tear substitute). Administration schedules varied from 3 to 8 instillations per day for 7 to 84 days, and evaluation timepoints varied between studies. Pre-corneal retention of Lacrycon was 22% better than phosphate-buffered saline in terms of AUC (P=0.048). Patients' evaluation of efficacy was better for Lacrycon than Gel-larmes on Day 15 and 45 (P<0.05) and similar on Day 90 (P>0.05); there was no difference (P>0.05) versus Hyalistil (Day 30) or Vismed (Day 35 and 85). Functional tests were either in favor of Lacrycon (P<0.05) (fluorescein test [versus Gel-larmes/Lacrisol/Hyalistil], tear break-up time [TBUT] and rose Bengal test, Schirmer I test, and tear meniscus [versus Lacrisol]), or there was no difference between treatments (P>0.05) (fluorescein test [versus Vismed], TBUT and rose Bengal test [versus Gel-larmes], Schirmer I test [versus Gel-larmes/Lacrisol/Hyalistil/VisMed], tear meniscus [versus Lacrisol/Hyalistil], Oxford Grading Score, OSDI, van Bijsterveld score, and conjunctival hyperemia [versus Vismed]). Lacrycon was better tolerated than most comparators and had a similar safety profile to Vismed. No comparison showed favored the comparator over Lacrycon. These good efficacy, tolerability and safety data support the use of Lacrycon in dry eye syndrome.

Inverse gas chromatography for natural fibre characterisation: Identification of the critical parameters to determine the Brunauer-Emmett-Teller specific surface area.

Inverse gas chromatography (IGC) is an alternative technique to determine the specific surface area of natural fibres. Natural fibres have a complex surface chemistry and unique microstructure that challenge the current capabilities to perform surface characterisation. This study investigated the influence of multiple parameters on the measured Brunauer-Emmett-Teller (BET) specific surface area for samples of flax, kenaf and BioMid(®) cellulose fibres using IGC. The BET surface area of kenaf and flax differed with 0.51m(2)g(-1) and 1.35m(2)g(-1) respectively, the former being similar to the cellulose fibres (0.54m(2)g(-1)). The data was calculated under conditions where the BET equation showed good linearity (R(2)⩾0.995). Repeatability was excellent so that two runs sufficed to obtain representative BET surface area values. The findings showed the choice of solvent was important for all specimens to avoid any misleading data comparison due to molecular orientation effects that impact the adsorbent-adsorbate interactions. The higher surface area of the flax sample, and its higher variability, was correlated with a higher surface roughness observed under optical microscopy. Packing the chromatography column with long or chopped fibres produced results that were statistically insignificant.

Utility of isotachophoresis-capillary zone electrophoresis, mass spectrometry and high-performance size-exclusion chromatography for monitoring of interleukin-6 dimer formation.

The utility of isotachophoresis-capillary zone electrophoresis (ITP-CZE) and high-performance size-exclusion chromatography (HPSEC) was investigated for determination of dimeric and monomeric recombinant human interleukin-6 (rhIL-6). Using ITP-CZE heterogeneity of dimeric rhIL-6 could be revealed resolving two peaks in the electropherograms, while with HPSEC dimeric rhIL-6 eluted as one homogeneous fraction. Both protein forms were monitored during incubation of monomeric rhIL-6 at different pH and temperature. The selectivity of counterflow ITP-CZE in conjunction with the low concentration determination limits enabled reanalysis of HPSEC fractions for identification of the dimer in the electropherograms. Both ITP-CZE and HPSEC were shown to be suitable to monitor the dimerization of rhIL-6, similar monomer-to-dimer peak area ratios were obtained throughout the incubation. Dimer formation kinetics increased with decreasing pH and with increasing temperature, it was entirely suppressed at neutral pH and room temperature. In contrast to HPSEC, ITP-CZE enabled separation of further still unidentified artifacts apparently formed during incubation of rhIL-6. CZE analysis in conjunction with electrospray ionization mass spectrometry revealed the non-covalent binding character of the dimeric rhIL-6 complex and facilitated interpretation of the electropherograms.

Low-loss submicrometer silicon-on-insulator rib waveguides and corner mirrors.

Rib microwaveguides are demonstrated on silicon-on-insulator substrates with Si film thickness of either 380 or 200 nm and a width of 1 microm. Corner mirrors that allow compact 90 degrees turns between two perpendicular waveguides are characterized. Measured propagation losses are approximately 0.4 dB/cm and approximately 0.5 dB/cm for 380-nm and 200-nm Si film, respectively, and mirror losses are approximately 1 dB. This allows the development of applications such as optical interconnects in integrated circuits over propagation distances larger than several centimeters.

Interplay of intrinsic and environmental effects on the magnetic properties of free radicals issuing from H-atom addition to cytosine.

Possible radical reaction products issuing from H-atom addition to cytosine have been characterized and analyzed by means of a comprehensive quantum mechanical approach including density functional computations (B3LYP), together with simulation of the solvent by the polarizable continuum model (PCM), and averaging of spectroscopic properties over the most important vibrational motions. The hyperfine couplings of the semirigid 5,6-dihydrocytos-6yl radical computed at the optimized geometry are in good agreement with their experimental counterparts. On the other hand, vibrational averaging is mandatory for obtaining an effectively planar structure for the 5,6-dihydrocytos-5yl radical with the consequent equivalence of beta-hydrogens. Finally, only proper consideration of environmental effects restores the agreement between computed and experimental couplings for the base anion protonated at N3.