Background & Aims Consumption of sugar is associated with obesity, type 2 diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular disease. The conversion of fructose to fat in liver (de novo lipogenesis, DNL) may be a modifiable pathogenetic pathway. We determined the effect of 9 days of isocaloric fructose restriction on DNL, liver fat, visceral fat (VAT), subcutaneous fat, and insulin kinetics in obese Latino and African American children with habitual high sugar consumption (fructose intake more than 50 g/day). Methods Children (9–18 years old; n = 41) had all meals provided for 9 days with the same energy and macronutrient composition as their standard diet, but with starch substituted for sugar, yielding a final fructose content of 4% of total kcal. Metabolic assessments were performed before and after fructose restriction. Liver fat, VAT, and subcutaneous fat were determined by magnetic resonance spectroscopy and imaging. The fractional DNL area under the curve value was measured using stable isotope tracers and gas chromatography/mass spectrometry. Insulin kinetics were calculated from oral glucose tolerance tests. Paired analyses compared change from day 0 to day 10 within each child. Results Compared with baseline, on day 10, liver fat decreased from a median of 7.2% (inter-quartile range, 2.5%–14.8%) to 3.8% (inter-quartile range, 1.7%–15.5%)(P<.001) and VAT decreased from 123 cm3 (inter-quartile range, 85–145 cm3) to 110 cm3 (inter-quartile range, 84–134 cm3) (P<.001). The DNL area under the curve decreased from 68% (inter-quartile range, 46%–83%) to 26% (inter-quartile range, 16%–37%) (P<0.001). Insulin kinetics improved (P<.001). These changes occurred irrespective of baseline liver fat. Conclusions Short-term (9 day) isocaloric fructose restriction decreased liver fat, VAT, and DNL, and improved insulin kinetics in children with obesity. These findings support efforts to reduce sugar consumption. ClinicalTrials.gov no: NCT01200043

The 1980 identification of nitric oxide (NO) as an endothelial cell-derived relaxing factor resulted in an unprecedented biomedical research of NO and established NO as one of the most important cardiovascular, nervous and immune system regulatory molecule. A reduction in endothelial cell NO levels leading to "endothelial dysfunction" has been identified as a key pathogenic event preceding the development of hypertension, metabolic syndrome, and cardiovascular disease. The reduction in endothelial NO in cardiovascular disease has been attributed to the action of oxidants that either directly react with NO or uncouple its substrate enzyme. In this report, we demonstrate that uric acid (UA), the most abundant antioxidant in plasma, reacts directly with NO in a rapid irreversible reaction resulting in the formation of 6-aminouracil and depletion of NO. We further show that this reaction occurs preferentially with NO even in the presence of oxidants peroxynitrite and hydrogen peroxide and that the reaction is at least partially blocked by glutathione. This study shows a potential mechanism by which UA may deplete NO and cause endothelial dysfunction, particularly under conditions of oxidative stress in which UA is elevated and intracellular glutathione is depleted.

Hyperuricemia is associated with hypertension, metabolic syndrome, preeclampsia, cardiovascular disease and renal disease, all conditions associated with oxidative stress. We hypothesized that uric acid, a known antioxidant, might become prooxidative following its reaction with oxidants; and, thereby contribute to the pathogenesis of these diseases. Uric acid and 1,3-15N2-uric acid were reacted with peroxynitrite in different buffers and in the presence of alcohols, antioxidants and in human plasma. The reaction products were identified using liquid chromatography-mass spectrometry (LC-MS) analyses. The reactions generate reactive intermediates that yielded triuret as their final product. We also found that the antioxidant, ascorbate, could partially prevent this reaction. Whereas triuret was preferentially generated by the reactions in aqueous buffers, when uric acid or 1,3-15N2-uric acid was reacted with peroxynitrite in the presence of alcohols, it yielded alkylated alcohols as the final product. By extension, this reaction can alkylate other biomolecules containing OH groups and others containing labile hydrogens. Triuret was also found to be elevated in the urine of subjects with preeclampsia, a pregnancy-specific hypertensive syndrome that is associated with oxidative stress, whereas very little triuret is produced in normal healthy volunteers. We conclude that under conditions of oxidative stress, uric acid can form reactive intermediates, including potential alkylating species, by reacting with peroxynitrite. These reactive intermediates could possibly explain how uric acid contributes to the pathogenesis of diseases such as the metabolic syndrome and hypertension.

Objective To determine the effects of supplemental fiber on plasma p-cresol, stool frequency, and quality of life (QoL) in chronic kidney disease (CKD) patients. Design and Setting In a 12-week single-blind study, participants were provided with control muffins and supplements (5.5 g sucrose/day) for 2 weeks, muffins containing 10 g/day pea hull fiber and control supplements for 4 weeks, and muffins with 10 g/day pea hull fiber and 15 g/day inulin as a supplement for 6 weeks. Subjects Individuals with CKD (n = 13; 6 males, 7 females; aged 65 ± 3 years; estimated glomerular filtration rate <50 mL/minute/1.732) completed the study. Main Outcome Measures Plasma p-cresol was determined by gas chromatography-mass spectrometry, stool frequency by 5-day journals, and QoL by the KDQOL-36™. Results Plasma p-cresol decreased from 7.25 ± 1.74 mg/L during week 1 to 5.82 ± 1.72 mg/L during week 12 (P < .05), and in participants with high compliance (>70% inulin intake), from 6.71 ± 1.98 mg/L to 4.22 ± 1.16 mg/L (P < .05). Total fiber intake increased from 16.6 ± 1.7 g/day during control to 26.5 ± 2.4 g/day (P < .0001) with the added pea hull and to 34.5 ± 2.2 g/day with pea hull and inulin (P < .0001). Stool frequency increased from 1.4 ± 0.2 stools/day during control to 1.9 ± 0.3 stools/day during both fiber periods (P < .05). No change in overall QoL was observed. Conclusions Supplementing the diet of CKD patients with fiber may be a dietary therapy to reduce p-cresol and improve stool frequency.

A miniaturized two-electrode electrochemical (EC) cell was developed and was coupled on-line with an electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESI-FTICR MS). Electrochemistry on-line with mass spectrometry, EC/ESI-FTICR MS, of triphenylamine (TPA), which undergoes one-electron oxidation to form a radical cation (TPA •+ ), demonstrates a significant sensitivity enhancement compared to ESI-FTICR MS. The on-line EC cell configuration with a stainless steel ES needle as the working electrode produces the highest sensitivity in EC/ESI-MS. The results provide evidence that, during the ES ionization, electrolytic reactions occur mainly in the ES tip region, as previously predicted. The results demonstrate that ESI-MS signal suppression by tetrabutylammonium perchlorate electrolyte, which can be a problem, is minimized in EC/ESI-MS. TPA •+ dimer tetraphenylbenzidine (TPB) can be detected by EC/ESI-MS, together with TPA •+ , as TPB •+ and TPB 2+ . The high mass resolving power of FTICR MS was exploited to identify TPB 2+ dication in the presence of [TPA •+ -H • ] + ions of the same m/z, from their respective isotopic distributions. The dimer dication TPB 2+ can be detected only in EC/ESI-MS.On-line combination of electrochemistry (EC) and mass spectrometry (MS), EC/MS, is an excellent tool for probing electron-transfer chemistry in solution in close to real time. 1 In most recent developments in EC/MS, several research groups have reported the use of an electrospray ionization (ESI) interface for coupling of electrochemistry to mass spectrometry. 2-10 ESI is a soft ionization method, which operates at atmospheric pressure