Water soluble selenometabolome of Cardamine violifolia.

Low molecular weight selenium containing metabolites in the leaves of the selenium hyperaccumulator Cardamine violifolia (261 mg total Se per kg d.w.) were targeted in this study. One dimensional cation exchange chromatography coupled to ICP-MS was used for purification and fractionation purposes prior to LC-Unispray-QTOF-MS analysis. The search for selenium species in full scan spectra was assisted with an automated mass defect based filtering approach. Besides selenocystathionine, selenohomocystine and its polyselenide derivative, a total number of 35 water soluble selenium metabolites other than selenolanthionine were encountered, including 30 previously unreported compounds. High occurrence of selenium containing hexoses was observed, together with the first assignment of N-glycoside derivatives of selenolanthionine. Quantification of the most abundant selenium species, selenolanthionine, was carried out with an ion pairing LC - post column isotope dilution ICP-MS setup, which revealed that this selenoamino acid accounted for 30% of the total selenium content of the leaf (78 mg (as Se) per kg d.w.).

Mapping of selenium metabolic pathway in yeast by liquid chromatography-Orbitrap mass spectrometry.

A high-resolution mass spectrometric detection method is described for the identification of key metabolites in the selenium pathway in selenium enriched yeast. Iodoacetic acid (IAA) was used as the derivatizing reagent to stabilize the selenols. Oxidized forms of selenocysteine (Se-Cys), selenohomocystine (Se-HCys), selenoglutathione (Se-GSH), seleno-γ-glutamyl-cysteine (Se-Glu-Cys), N-(2,3-dihydroxy-1-oxopropyl)-selenocysteine (Se-DOP-Cys), N-(2,3-dihydroxy-1-oxopropyl)-selenohomocysteine (Se-DOP-HCys), selenomethionine (SeMet), seleno-S-adenosyl-homocysteine (Se-AdoHcy), the conjugate of glutathione and N-(2,3-dihydroxy-1-oxopropyl)-selenocysteine (GSH-Se-DOP-Cys), and the conjugate of glutathione and N-(2,3-dihydroxy-1-oxopropyl)-selenohomocysteine (GSH-Se-DOP-HCys) were found in the selenium enriched yeast certified reference material (SELM-1). Selenols were also derivatized with a mercury tag, p-hydroxymercurybenzoate (PHMB). The selenol-PHMB complexes showed the overlapped isotopic patterns of selenium and mercury, which provided supporting information for the identification of selenols. Both methods showed good agreement (<4 ppm difference) between the theoretical masses of the target compounds and the measured masses in the yeast matrix. The method using IAA as the derivatizing reagent was used to study the response of Saccharomyces cerevisiae to three forms of selenium, Se-Met, Na(2)SeO(3) (Se(IV)), and Na(2)SeO(4)·10H(2)O (Se(VI)) (concentration of Se: 100 mg/L). The production of selenocompounds observed over a 6 h period was high in the Se-Met treated group compared to the groups treated with Se(IV) and Se(VI).

Experimental hyperhomocysteinaemia: differences in tissue metabolites between homocystine and methionine feeding in a rat model.

AIM: Hyperhomocysteinaemia, diagnosed by serum levels, is regarded as an independent risk indicator for cardiovascular events and is associated with various diseases. The pathomechanisms seem to be partly due to concentrations of homocysteine metabolites and their effect on the cellular transmethylation processes. METHODS: We compared two common models for experimental hyperhomocysteinaemia - high methionine diet and homocystine-enriched diet - regarding their effects on tissue concentrations of homocysteine metabolites. RESULTS: Both diets induced hyperhomocysteinaemia without affecting renal function or vitamine status. However, the tissue contents of homocysteine and its precursors S-adenosyl-homocysteine (SAH) and S-adenosyl-methionine exhibited major differences between both models. Transmethylation potential was elevated 1.7-fold in liver of rats fed the methionine diet, whereas it was unaltered after homocystine-enriched diet. Kidneys of rats fed the methionine diet did not show any alterations in tissue content of homocysteine and its precursors, whereas in the homocystine group homocysteine and the transmethylation inhibitor SAH were elevated from 23.1 +/- 10.4 to 78.0 +/- 26.0 nmol g(-1) and from 106 +/- 4 to 170 +/- 22 nmol g(-1) respectively. Homocysteine tissue content was elevated in the homocystine, but not in the methionine group. CONCLUSIONS: Alterations to homocysteine metabolism are distinct in both models. These findings may explain divergent results, which have been published for these models of hyperhomocysteinaemia and which have resulted in controversial discussions in the past.

2 minute non-invasive screening for cardio-vascular diseases: relative limitation of C-Reactive Protein compared with more sensitive L-Homocystine as cardio-vascular risk factors; safe and effective treatment using the selective drug uptake enhancement method.

Contrary to the present practice of measurement of cardio-vascular risk factors or inflammatory risk factors such as C-Reactive Protein (CRP) from a blood sample from the vein of one arm, by using the Bi-Digital O-Ring Test Resonance Phenomena between 2 identical substances, one can non-invasively detect the approximate location on the body of abnormally increased risk factors in just 2 minutes, by detecting the resonance with L-Homocystine, even when blood CRP failed to detect any abnormality. This is performed by projecting a 0.5 to approximately 5mW red spectral laser beam with 560-670nm wavelength, to at least 6 standard parts of the body, when one of the control risk markers placed next to the laser beam also exists in the part of the body tested. It is generally believed that CRP is increased in the presence of acute myocardial infarct, chronic rheumatoid arthritis, ulcerative colitis, metabolic abnormalities such as often detected in diabetes, inflammation and underlying infection of the cardio-vascular system, and in some cancers. However, in our study, when the clinical significance of CRP and L-Homocystine was compared, we found that CRP often was not increased when there was extensive infection of Mycobacterium Tuberculosis as well as asymptomatic infection by Cytomegalovirus, Herpes Simplex Virus Type I, Human Herpes Virus Type 6, Borrelia Burgdorferi, or Chlamydia Trachomatis in the heart (and other parts of the body), particularly when there was liver cell dysfunction such as an increase in ALT. In contrast, L-Homocystine was often increased in the presence of localized infections of the heart and other parts of the body. For screening of Cardio-Vascular diseases by this method, 0.5mg of L-Homocystine as a control marker was found to be the most sensitive and reliable, compared with most effective amount of CRP, 0.5ng, for detecting early Cardio-Vascular problems due to various localized infections. About 0.5ng of cardiac Troponin T and cardiac Troponin I were also useful for detecting early stages of heart disease but they are not as sensitive as L-Homocystine. Once the pathogenic factors were identified, the effective medication was given, and the Selective Drug Uptake Enhancement Method (originally discovered by the first author in 1990) was applied after the effective drug was administered, to selectively deliver the medication to the pathological area, while reducing drug uptake to the normal parts of the body. As a result, the therapeutic effect was markedly accelerated.

[Homocysteine and hyperhomocysteinemia]. / Homocysteina i hiperhomocysteinemia.

This paper reviews the biochemical and physiological data underlying hyperhomocysteinemia. Elevation of plasma homocysteine arises from disrupted of its metabolism (remethylation to methionine and transsulfuration to cystathionine) and is a function of a complex interaction between multiple genetic and environmental factors. Hyperhomocysteinemia, a conditions that recent epidemiological studies have shown to be associated with an increased risk of vascular diseases, may be a equal importance to hypercholesterolemia, hypertension and smoking in etiology of atherosclerosis. Based on the role of folic acid, vitamin B12 and B6 in homocysteine metabolism supplementation with these vitamins in treatment of hyperhomocysteinemia both in cardiovascular diseases and neural tube defects is reviewed.

Prevention of neural tube defects by and toxicity of L-homocysteine in cultured postimplantation rat embryos.

Mild hyperhomocysteinemia is frequently observed in mothers who gave birth to a child with a neural tube defect (NTD). In a previous study we showed L-homocysteine was embryotoxic to gestational day 10 (GD10) rat embryos in culture, however, no NTDs were observed. We therefore investigated the effect of L-homocysteine on the development of neural plate stage (GD9.5) rat embryos. Other objectives of this study were investigation into whether the embryotoxicity of L-homocysteine could be attenuated by compounds related to its metabolism and clarification of the mechanism of L-homocysteine embryotoxicity. In GD9.5 rat embryos L-homocysteine was not toxic at 1- and 2-mM concentrations. Rather at these concentrations it promoted development of the rat embryos in serum that without supplementation caused NTDs in the embryos. L-Methionine had the same preventive effect at even lower concentrations, but folinic acid (1 mM) did not improve embryonic development. N5-Methyltetrahydrofolate (5-CH3-THF) (100 microM), L-serine (6 mM), and L-methionine (6 and 12 mM) attenuated the embryotoxicity of L-homocysteine (6 mM) in GD10 rat embryos. Vitamin B12 (10 microM) completely abolished the embryotoxicity of L-homocysteine, which was shown to be mediated by catalysis of the spontaneous oxidation of L-homocysteine to the less toxic L-homocystine. In GD11 rat embryos, both L- and D-homocysteine were readily taken up when added to the culture (3 mM) and increased embryonic S-adenosylhomocysteine (SAH) levels 14- and 3-fold, respectively. This difference was shown to be caused by the stereospecific preference of SAH hydrolase. We propose the basis for L-homocysteine embryotoxicity is an inhibition of transmethylation reactions by increased embryonic SAH levels.

Homocystine, atherosclerosis and thrombosis: implications for oral contraceptive users.

PIP: Individuals with homocystinuria have been found to suffer from several types of inherited enzymatic deficiencies. Experiments indicated that vascular changes were subsequent to the metabolic effects of homocysteine derivatives in the tissues. Experimental studies in animals showed that homocysteine thiolactone, methionine, homocysteic acid, and homocystine cause fibrous arteriosclerotic plaques, arterial thrombosis or venous thrombosis with pulmonary embolism. The type which develops depends on the particular homocystine derivative, the dose, and the route of administration. The use of oral contraceptives causes similar alterations in nutrient metabolism. This fact suggests the possibility of increased risk of atherosclerosis, thrombosis, and embolism among long-term oral contraceptive users. Pyridoxine supplementation may reduce the risk. Further research is needed to assess the degree of risk involved.^ieng