Developmental changes in the L-arginine/nitric oxide pathway from infancy to adulthood: plasma asymmetric dimethylarginine levels decrease with age

Background: The L-arginine/nitric oxide (NO) pathway has multiple physiological functions including vasodilation, inhibition of platelet aggregation and neurotransmission. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of all known NO synthase isoforms, has adverse effects on renal and cardiovascular function in adults. It is unknown whether ADMA might also exert similar effects in younger individuals including infants. Also, reference data for important members of the L-arginine/NO family, notably ADMA and the NO metabolites, nitrite and nitrate, in infancy are lacking. Methods: In the present study, we investigated the status of the L-arginine/NO pathway in 34 healthy volunteers aged 2days to 24years by measuring the concentration of ADMA, nitrite, nitrate and L-arginine in plasma and urine using gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry methods. Results: We found that ADMA levels in plasma decreased with age (Pearson correlation coefficient r=-0.619, p<0.001). In contrast, urinary excretion of nitrate (r=0.471, p=0.036) and nitrite increased with age (r=0.484, p=0.037). Conclusions: Our study suggests that in infants ADMA biosynthesis accompanied by an inhibition of NO synthesis is higher than in adults and diminishes considerably with age. Clin Chem Lab Med 2007;45:1525-3

Elevated asymmetric dimethylarginine (ADMA) and inverse correlation between circulating ADMA and glomerular filtration rate in children with sporadic focal segmental glomerulosclerosis (FSGS)

Background. Steroid-resistant nephrotic syndromes (NS) with focal and segmental glomerulosclerosis (FSGS) can be differentiated into sporadic and syndromic forms. In sporadic NS, a circulating FSGS-factor is discussed in the pathogenesis and is thought to inhibit the synthesis of nitric oxide (NO) from l-arginine by blocking the NO synthase (NOS). Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of all types of NOS. In a previous study we did not find an elevation of ADMA in a syndromic form of FSGS, the Schimke-immuno-osseous dysplasia. Here we report for the first time data on the l-arginine/NO pathway in sporadic FSGS of childhood. Methods. Nine children (5 to 18 years of age) suffering from sporadic FSGS and age-matched healthy controls were investigated. ADMA in plasma and urine as well as l-arginine in plasma were determined by gas chromatography-tandem mass spectrometry. The NO metabolites nitrate and nitrite were measured in plasma and urine by gas chromatography-mass spectrometry (GC-MS). The ADMA metabolite dimethylamine (DMA) was measured in urine by GC-MS. Results. We found elevated plasma levels of ADMA in children suffering from sporadic FSGS compared to healthy controls (851 nmol/L versus 684 nmol/L, P = 0.008). An inverse correlation between ADMA and glomerular filtration rate (GFR) was found in sporadic FSGS (Pearson's correlation coefficient −0.784, P = 0.012). Conclusion. Our study suggests that ADMA synthesis is elevated in sporadic FSGS. This finding argues for the involvement of ADMA in the pathogenesis of this disease in childhoo

Methodology and Reductionism in the Philosophy of Mind

In contemporary philosophy of mind, the mind-body problem is often framed in terms ofthe reduction of psychology to neuroscience. In this thesis I argue that whether or notone regards such a reduction as tenable depends upon a methodological decision aboutthe importance of our naïve intuitions concerning the mind and the material world. Iclaim that standard anti-reductive argumentative strategies rest upon systematicallydeceptive and underdeveloped intuitions. As a result, we should reject these intuitionsand forms of argumentation and adopt instead a pragmatic philosophy of mind that allowsfor the principled reduction of psychology, but at the time time maintains a pluralisticmethodology

Removal of Copper from a Metal-Complex Dye by Oxidative Pretreatment and Ion Exchange

The recovery of copper from solution containing Direct Blue 80 (C.I. 24315), a common metal-complex dye, was examined using ion exchange preceded by oxidative pretreatment using ozone alone and in combination with hydrogen peroxide. The minimum ozone dosages were 0.1 and 0.2 mg dye for maximum total and breakthrough capacities, respectively. Ion exchange was performed using a strong acid cation-exchange resin. The optimal ion-exchange pH levels were 2 and from 3 to 4 for maximum total and breakthrough capacities, respectively. The data suggest that the released copper existed in dynamic equilibrium with both the exchange resin and oxidation byproducts of the organic dye molecule. Ozonation, followed by ion exchange, may be a viable method of removing copper from textile wastewaters containing copper-complex dyes. Because only minimal organic carbon is exchanged onto the ion-exchange resin, the integrated chemical oxidation and ion-exchange process has significant potential as a means to recycle or recover copper from textile wastewaters

Ozone, Hydrogen Peroxide/Ozone and UV/Ozone Treatment of Chromium- and Copper-Complex Dyes: Decolorization and Metal Release

Metal-complex azo dyes constitute a significant fraction of the dyes used in the textile industry and exhibit properties such as superior light- and wash-fastness. While effluent color is not always regulated, the textile finishing industry often decolorizes wastewater using processes including chemical oxidation. In this study, the use of ozone, hydrogen peroxide/ozone and UV/ozone oxidant systems was examined for treatment of two common metal-complex (premetalized) dyes, Acid Black 52 (chromium) and Direct Blue 80 (copper). Oxidant dosages required for decolorization of these dyes were determined. The effect of bicarbonate alkalinity on the ozonation and the hydrogen peroxide/ozone processes also was examined