390 research outputs found

    Carbon exchange of grass in Hungary

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    Continuous measurement of net biosphere-atmosphere carbon exchange was performed in western Hungary over a managed semi-natural grassland field using the eddy covariance technique to estimate Net Ecosystem Exchange (NEE). The paper presents the measuring site and instrumentation, as well as the data processing methods applied. The measurements covered the period March 1999 to December 2000 during which, on an annual time scale, the region acted as a net CO2 sink, where NEE was -54 g C m(-2) in 1999 (data for January and February were estimated) and -232 g C m(-2) in 2000 (negative NEE represents CO2 uptake by the vegetation). The remarkable inter-annual difference may be the result of the significant climate difference between 1999 and 2000

    Development of a simultaneous analytical method for five conjugated cholesterol metabolites in urine and investigation of their performance as diagnostic markers for Niemann-Pick disease type C

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    Niemann-Pick disease type C (NPC) is an autosomal recessive disorder characterized by progressive nervous degeneration. Because of the diversity of clinical symptoms and onset age, the diagnosis of this disease is difficult. Therefore, biomarker tests have attracted significant attention for earlier diagnostics. In this study, we developed a simultaneous analysis method for five urinary conjugated cholesterol metabolites, which are potential diagnostic biomarkers for a rapid, convenient, and noninvasive chemical diagnosis, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). By the method, their urinary concentrations were quantified and the NPC diagnostic performances were evaluated. The developed LC/MS/MS method showed high accuracy and and satisfied all analytical method validation criteria. Analyzing the urine of healthy controls and patients with NPC, three of five urinary conjugated cholesterol metabolites concentrations corrected by urinary creatinine were significantly higher in the patients with NPC. As a result of receiver operating characteristics analysis, the urinary metabolites might have excellent diagnostic marker performance. 3β-sulfooxy-7β-hydroxy-5-cholenoic acid showed particularly excellent diagnostic performance with both 100% clinical sensitivity and specificity, suggesting that it is a useful NPC diagnostic marker. The urinary conjugated cholesterol metabolites exhibited high NPC diagnostic marker performance and could be used for NPC diagnosis

    Structural Determination of Lysosphingomyelin-509 and Discovery of Novel Class Lipids from Patients with Niemann–Pick Disease Type C

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    Niemann–Pick disease type C (NPC) is an autosomal recessive disorder caused by the mutation of cholesterol-transporting proteins. In addition, early treatment is important for good prognosis of this disease because of the progressive neurodegeneration. However, the diagnosis of this disease is difficult due to a variety of clinical spectrum. Lysosphingomyelin-509, which is one of the most useful biomarkers for NPC, was applied for the rapid and easy detection of NPC. The fact that its chemical structure was unknown until recently implicates the unrevealed pathophysiology and molecular mechanisms of NPC. In this study, we aimed to elucidate the structure of lysosphingomyelin-509 by various mass spectrometric techniques. As our identification strategy, we adopted analytical and organic chemistry approaches to the serum of patients with NPC. Chemical derivatization and hydrogen abstraction dissociation–tandem mass spectrometry were used for the determination of function groups and partial structure, respectively. As a result, we revealed the exact structure of lysosphingomyelin-509 as N-acylated and O-phosphocholine adducted serine. Additionally, we found that a group of metabolites with N-acyl groups were increased considerably in the serum/plasma of patients with NPC as compared to that of other groups using targeted lipidomics analysis. Our techniques were useful for the identification of lysosphingomyelin-509

    Nicotinamide benefits both mothers and pups in two contrasting mouse models of preeclampsia

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    Preeclampsia (PE), high blood pressure and protein in the urine in the last third of pregnancy, complicates about 1 in 20 human pregnancies, and it is one of the leading causes of pregnancy-related maternal deaths. The only definitive treatment, induced delivery, invariably results in premature babies. Blood pressure-lowering drugs help, but results in preventing preterm delivery and correcting the fetal growth restriction (FGR) that also occurs in PE have been disappointing. Here we show that feeding high doses of nicotinamide, a vitamin, improves the maternal condition, prolongs pregnancies, and prevents FGR in mice having PE-like conditions due to two contrasting causes. Because nicotinamide benefits both mothers and pups, it merits evaluation for preventing or treating PE in humans
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