A randomised interventional trial of ω-3-polyunsaturated fatty acids on endothelial function and disease activity in systemic lupus erythematosus

Objective: To determine the clinical effect of dietary supplementation with low-dose ?-3-polyunsaturated fatty acids on disease activity and endothelial function in patients with systemic lupus erythematosus. Methods: A 24-week randomised double-blind placebo-controlled parallel trial of the effect of 3 g of ?-3-polyunsaturated fatty acids on 60 patients with systemic lupus erythematosus was performed. Serial measurements of disease activity using the revised Systemic Lupus Activity Measure (SLAM-R) and British Isles Lupus Assessment Group index of disease activity for systemic lupus erythematosus (BILAG), endothelial function using flow-mediated dilation (FMD) of the brachial artery, oxidative stress using platelet 8-isoprostanes and analysis of platelet membrane fatty acids were taken at baseline, 12 and 24 weeks. Results: In the fish oil group there was a significant improvement at 24 weeks in SLAM-R (from 9.4 (SD 3.0) to 6.3 (2.5), p

Psychophysical Function in Age-related Maculopathy

Age-related macular degeneration (AMD), the late stage of age-related maculopathy (ARM), is the leading cause of blind registration in developed Countries. The Visual loss in AMD occurs due to dysfunction and death of photoreceptors (rods and cones) secondary to an atrophic or a neovascular event. The psychophysical tests of vision, which depend on the functional status of the photoreceptors, may detect subtle alterations in the macula before morphological fundus changes are apparent ophthalmoscopically, and before traditional measures of visual acuity exhibit deterioration, and may be a useful tool for assessing and monitoring patients with ARM. Furthermore, worsening of these visual functions over time may reflect disease progression, and some of these, alone or iti combination with other parameters, may act as a prognostic indicator for identifying eyes at, risk for developing neovascular AMD. Lastly, psychophysical tests often correlate with subjective and relatively undefined symptoms in patients With early ARM, and may reflect limitation of daily activities for ARM patients. However, clinical studies investigating psychophysical function have largely been cross-sectional in nature, with small sample sizes, and lack consistency in terms Of the grading and classification of ARM. This article aims to comprehensively review the literature germane to psychophysical tests in ARM, and to furnish the reader with an insight into this complex area of research. (Surv Ophdialmol 54:167-210, 2009. (C) 2009 Elsevier Inc. All rights reserved.)

Platelet Redox Balance in Diabetic Patients with Hypertension improved by n-3 fatty acids

OBJECTIVE:
Patients with type 2 diabetes mellitus (T2DM) are at increased risk of developing cardiovascular disease, largely as a result of defective production of cardioprotective nitric oxide and a concomitant rise in oxidative stress. Dietary interventions that could reverse this trend would be extremely beneficial. Here we investigated whether dietary n-3 polyunsaturated fatty acid (n-3 PUFA) supplementation positively affected platelet nitroso-redox imbalance.
RESEARCH DESIGN AND METHODS:
We randomized hypertensive T2DM patients (T2DM HT; n = 22) and age-and-sex matched hypertensive study participants without diabetes (HT alone; n = 23) in a double-blind, crossover fashion to receive 8 weeks of n-3 PUFAs (1.8 g eicosapentaenoic acid and 1.5 g docosahexaenoic acid) or identical olive oil capsules (placebo), with an intervening 8-week washout period. Platelet nitrite and superoxide were measured and compared before and after treatment; 8-isoprostane was determined by ELISA and subcellular compartmentalization of the NAD(P)H oxidase subunit p47-phox examined by Western blotting.
RESULTS:
The n-3 PUFA supplementation reduced 8-isoprostane and superoxide levels in platelets from T2DM HT, but not HT alone, participants, without effect on nitrite production. This coincided with a significant decrease in p47-phox membrane localization and a similar reduction in superoxide to that achieved with apocynin. At baseline, a subcohort of T2DM HT and HT alone participants showed evidence of nitric oxide synthase (NOS)-derived superoxide production, indicating defective enzymatic activity. This was reversed significantly in T2DM HT participants after treatment, demonstrating improved NOS function.
CONCLUSIONS:
Our finding that n-3 PUFAs diminish platelet superoxide production in T2DM HT patients in vivo suggests a therapeutic role for these agents in reducing the vascular-derived oxidative stress associated with diabetes.

In vivo and in vitro function of human UDP-galactose 4 '-epimerase variants

Type III galactosemia results from reduced activity of the enzyme UDP-galactose 4'-epimerase. Five disease-associated alleles (G90E, V94M, D103G, N34S and L183P) and three artificial alleles (Y105C, N268D, and M284K) were tested for their ability to alleviate galactose-induced growth arrest in a Saccharomyces cerevisiae strain which lacks endogenous UDP-galactose 4'-epimerase. For all of these alleles, except M284K, the ability to alleviate galactose sensitivity was correlated with the UDP-galactose 4'-epimerase activity detected in cell extracts. The M284K allele, however, was able to substantially alleviate galactose sensitivity, but demonstrated near-zero activity in cell extracts. Recombinant expression of the corresponding protein in Escherichia coil resulted in a protein with reduced enzymatic activity and reduced stability towards denaturants in vitro. This lack of stability may result from the introduction of an unpaired positive charge into a bundle of three alpha-helices near the surface of the protein. The disparities between the in vivo and in vitro data for M284K-hGALE further suggest that there are additional, stabilising factors present in the cell. Taken together, these results reinforce the need for care in the interpretation of in vitro, enzymatic diagnostic tests for type III galactosemia. (C) 2011 Elsevier Masson SAS. All rights reserved.

Divergence of chemical function in the alkaline phosphatase superfamily: Structure and mechanism of the P-C bond cleaving enzyme phosphonoacetate hydrolase

Phosphonates constitute a class of natural products that mimic the properties of the more common organophosphate ester metabolite yet are not readily degraded owing to the direct linkage of the phosphorus atom to the carbon atom. Phosphonate hydrolases have evolved to allow bacteria to utilize environmental phosphonates as a source of carbon and phosphorus. The work reported in this paper examines one such enzyme, phosphonoacetate hydrolase. By using a bioinformatic approach, we circumscribed the biological range of phosphonoacetate hydrolase to a select group of bacterial species from different classes of Proteobacteria. In addition, using gene context, we identified a novel 2-aminoethylphosphonate degradation pathway in which phosphonoacetate hydrolase is a participant. The X-ray structure of phosphonoformate-bound phosphonoacetate hydrolase was determined to reveal that this enzyme is most closely related to nucleotide pyrophosphatase/diesterase, a promiscuous two-zinc ion metalloenzyme of the alkaline phosphatase enzyme superfamily. The X-ray structure and metal ion specificity tests showed that phosphonoacetate hydrolase is also a two-zinc ion metalloenzyme. By using site-directed mutagenesis and P-32-labeling strategies, the catalytic nucleophile was shown to be Thr64. A structure-guided, site-directed mutation-based inquiry of the catalytic contributions of active site residues identified Lys126 and Lys128 as the most likely candidates for stabilization of the aci-carboxylate dianion leaving group. A catalytic mechanism is proposed which combines Lys12/Lys128 leaving group stabilization with zinc ion activation of the Thr64 nucleophile and the substrate phosphoryl group.

Determination of Non-linear Damping Coefficients of bottom-hinged Oscillating Wave Surge Converters Using Numerical Free Decay Tests

Linear wave theory models are commonly applied to predict the performance of bottom-hinged oscillating wave surge converters (OWSC) in operational sea states. To account for non-linear effects, the additional input of coefficients not included in the model itself becomes necessary. In ocean engineering it is
common practice to obtain damping coefficients of floating structures from free decay tests. This paper presents results obtained from experimental tank tests and numerical computational fluid dynamics simulations of OWSC’s. Agreement between numerical and experimental methods is found to be very good, with CFD providing more data points at small amplitude rotations.
Analysis of the obtained data reveals that linear quadratic-damping, as commonly used in time domain models, is not able to accurately model the occurring damping over the whole regime of rotation amplitudes. The authors
conclude that a hyperbolic function is most suitable to express the instantaneous damping ratio over the rotation amplitude and would be the best choice to be used in coefficient based time domain models.