Quantitation of Compounds in Wine Using (1)H NMR Spectroscopy: Description of the Method and Collaborative Study.

To examine whether NMR analysis is a suitable method for the quantitative determination of wine components, an international collaborative trial was organized to evaluate the method according to the international regulations and guidelines of the German Institute for Standardization/International Organization for Standardization, AOAC INTERNATIONAL, the International Union of Pure and Applied Chemistry, and the International Organization of Vine and Wine. Sugars such as glucose; acids such as malic, acetic, fumaric, and shikimic acids (the latter two as minor components); and sorbic acid, a preservative, were selected for the exemplary quantitative determination of substances in wine. Selection criteria for the examination of sample material included different NMR spectral signal types (singlet and multiplet), as well as the suitability of the proposed substances for manual integration at different levels of challenge (e.g., interference as a result of the necessary suppression of a water signal or the coverage of different typical wine concentration ranges for a selection of major components, minor components, and additives). To show that this method can be universally applied, NMR measurement and the method of evaluation were not strictly elucidated. Fifteen international laboratories participated in the collaborative trial and determined six parameters in 10 samples. The values, in particular the reproducibility SD (SR), were compared with the expected Horwitz SD (SH) by forming the quotient SR/SH (i.e., the HorRat value). The resulting HorRat values of most parameters were predominantly between 0.6 and 1.5, and thus of an acceptable range.

Differentiation of Organically and Conventionally Grown Tomatoes by Chemometric Analysis of Combined Data from Proton Nuclear Magnetic Resonance and Mid-infrared Spectroscopy and Stable Isotope Analysis.

Because the basic suitability of proton nuclear magnetic resonance spectroscopy ((1)H NMR) to differentiate organic versus conventional tomatoes was recently proven, the approach to optimize (1)H NMR classification models (comprising overall 205 authentic tomato samples) by including additional data of isotope ratio mass spectrometry (IRMS, δ(13)C, δ(15)N, and δ(18)O) and mid-infrared (MIR) spectroscopy was assessed. Both individual and combined analytical methods ((1)H NMR + MIR, (1)H NMR + IRMS, MIR + IRMS, and (1)H NMR + MIR + IRMS) were examined using principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and common components and specific weight analysis (ComDim). With regard to classification abilities, fused data of (1)H NMR + MIR + IRMS yielded better validation results (ranging between 95.0 and 100.0%) than individual methods ((1)H NMR, 91.3-100%; MIR, 75.6-91.7%), suggesting that the combined examination of analytical profiles enhances authentication of organically produced tomatoes.

Quantitative ¹H NMR analysis of egg yolk, alcohol, and total sugar content in egg liqueurs.

Analyzing egg liqueurs for compliance with legal requirements means several different time-consuming preparations and analytical processes. In this paper, we describe the approach to use quantitative (1)H NMR spectroscopy as an accurate alternative technique. (1)H NMR analysis comprised two different rapid sample preparations for water-soluble or nonpolar ingredients. Fifteen egg liqueurs were analyzed for alcoholic strength and content of total sugar and egg yolk (estimated by cholesterol as a marker substance) with both classical methods and quantitative (1)H NMR spectroscopy. The results of both methods showed excellent correlations for alcoholic strength (R = 0.996, p < 0.001) and content of total sugar (R = 0.989, p < 0.001) and cholesterol (R = 0.995, p < 0.001). Besides, NMR spectra revealed further information: a signal of phosphatidylcholine at about δ = 3.20 ppm served as a second marker for the egg yolk content, and characteristic signals of lactose at δ = 4.46 ppm and butyric acid at δ = 0.97 ppm indicated the use of milk products, which has to be declared for lactose-intolerant consumers.

1H NMR profiling as an approach to differentiate conventionally and organically grown tomatoes.

This study describes the approach of (1)H NMR profiling for the authentication of organically produced tomatoes (Solanum lycopersicum). Overall, 361 tomato samples of two different cultivars and four different producers were regularly analyzed during a 7 month period. The results of principal component analysis showed a significant trend for the separation between organically and conventionally produced tomatoes (p < 0.001 using the t test). Linear discriminant analysis demonstrated good discrimination between the growing regimens, and external validation showed 100% correctly classified tomato samples. Further validation studies, however, also disclosed unexpected differences between individual producers, which interfere with the aim of predicting the cultivation method, yet the results indicate significant differences between (1)H NMR spectra of organically and conventionally grown tomatoes.

Quantification of taurine in energy drinks using ¹H NMR.

The consumption of so called energy drinks is increasing, especially among adolescents. These beverages commonly contain considerable amounts of the amino sulfonic acid taurine, which is related to a magnitude of various physiological effects. The customary method to control the legal limit of taurine in energy drinks is LC-UV/vis with postcolumn derivatization using ninhydrin. In this paper we describe the quantification of taurine in energy drinks by (1)H NMR as an alternative to existing methods of quantification. Variation of pH values revealed the separation of a distinct taurine signal in (1)H NMR spectra, which was applied for integration and quantification. Quantification was performed using external calibration (R(2)>0.9999; linearity verified by Mandel's fitting test with a 95% confidence level) and PULCON. Taurine concentrations in 20 different energy drinks were analyzed by both using (1)H NMR and LC-UV/vis. The deviation between (1)H NMR and LC-UV/vis results was always below the expanded measurement uncertainty of 12.2% for the LC-UV/vis method (95% confidence level) and at worst 10.4%. Due to the high accordance to LC-UV/vis data and adequate recovery rates (ranging between 97.1% and 108.2%), (1)H NMR measurement presents a suitable method to quantify taurine in energy drinks.

[Soluble interleukin-2 and tumor necrosis factor receptor in liver cirrhosis. Relationship with clinical severity and prognosis]. / Receptores solubles de la interleucina 2 y del factor de necrosis tumoral en la cirrosis hepática de diversas etiologías. Relación con el pronóstico y la gravedad clínica.

BACKGROUND AND OBJECTIVE: The mechanism responsible for the beginning and progression of hepatic injury in liver cirrhosis of viral and alcoholic etiology are unknown currently. However, there are abnormalities in the immune system which may be implied in the pathogenesis. PATIENTS AND METHOD: The concentrations of the soluble receptor of tumor necrosis factor (sTNF-R55) and the soluble receptor of interleukin-2 (sIL-2R) in 49 cirrhotic patients were determined by enzyme-linked inmunoassay. Patients were grouped according to the etiology (33 alcoholic and 16 viral) and prognosis (Child-Pugh classification) and they were compared with the values obtained in 26 healthy non-drinkers who made up the control group. RESULTS: The concentrations of sTNF-R55 and sIL-2R were significantly higher in both groups of patients when compared with controls. We found significant differences in sTNF-R55 concentrations in viral and alcoholic but not in sIL-2R concentrations. There was a positive correlation between the concentrations of both receptors and the degrees of Child-Pugh classification, as well as with albumin, total bilirubin and alkaline phosphatase (all of them parameters related to the severity and prognosis of liver cirrhosis). CONCLUSIONS: The serum concentrations of soluble receptors of tumor necrosis factor and interleukin-2 correlate with the prognosis of liver cirrhosis independently of its etiology. This fact may reflect the stimulation of T lymphocytes, monocytes and macrophages, in liver cirrhosis.

Differential patterns of serum biomarkers of immune activation in human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis, and adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with differing patterns of immune dysfunction. Biomarkers of immune activation may correlate with perturbations of immune function associated with these diseases. We conducted a pilot cross-sectionalstudy to assess four candidate biomarkers of immune activation, beta 2-microglobulin, neopterin, tryptophan, and kynurenine levels were assayed in storedsera from asymptomatic, human T-cell leukemia virus type I (HTL V-I) seronegative (HTLV-I-) and HTLV-I-seropositive (HTLV-I+) individuals, and ATL and HAM/TSP patients previously enrolled in seroepidemiological studies in Jamaica. Mean levels of beta 2-microglobulin, neopterin, and kynurenine were significantly elevated among ATL patients compared to the other study groups. Mean tryptophan levels were signigicantly lower among ATL and HAM/TSP patients than HTLV-I- and HTLV-I+ groups. No significant differences in biomarkers were found between HTLV-I- and HTLV-I+ groups. Among HAM/TSP patients, a significant association was found between elevated neopterin levels and symptoms of less than 4 years duration. In Cox proportional hazards regression modeling, neopterin and tryptophan were found to be independent predictors of survival among ATL patients. This study demonstrates a differential pattern of biomarkers of immune activation among ATL and HAM/TSP patients compared to HTLV-I- amd HTLV-I+ individuals. Neopterin and tryptophan may be useful clinical indicators of disease severity and prognosis among HAM/TSP and ATL patients. (AU)

Cervical intraepithelial neoplasia is not associated with elevated serum neopterin levels

Neopterin, a marker of cellular immune activation, was elevated in patients who had cervical cancer in previous studies. To examine neopterin in the presence of precursors to cervical cancer (i.e. cervical intraepithelial) we measured serum levels in 185 colposcopy patients in Jamaica, a country with high cervical cancer incidence, and in 72 age-matched Jamaican women selected from a large population-based sample. We also measured serum levels of B-2 microglobulin, another commonly used marker of immune activation. Neopterin and B-2 microglobulin levels were not elevated in colposcopy patients; neither were they rel ted to severity of cervical neoplasia. In multivariable analysis, neither adjustments for detection of cervical human papillomavirus DNA by PCR nor detection of antibodies to human T-cell lymphotropic virus type 1 (a retrovirus endemic to Jamaica) altered our findings. The absence of serologically detectable increase in cellular immune activation linked to cervical intraepithelial neoplasmia does not involve susbtantial systemic immune activation. (AU)