92 research outputs found
Comparison of radiationless decay processes in osmium and platinum porphyrins
No full textTwo Osmium porphyrin complexes were investigated by picosecond laser spectroscop
The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans
No full textPurpose
To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content.
Methods
Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF and plasma was analysed with reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry detection (LCMS). Antioxidant capacity was estimated using the Trolox equivalent antioxidant capacity (TEAC) and polyphenol content using Folin–Ciocalteu colorimetric methods [gallic acid equivalents (GAE)] and betalain content spectrophotometrically.
Results
TEAC was 11.4 ± 0.2 mmol/L for BTJ and 3.4 ± 0.4 μmol/g for BF. Both BTJ and BF contained a number of polyphenols (1606.9 ± 151 mg/GAE/L and 1.67 ± 0.1 mg/GAE/g, respectively), betacyanins (68.2 ± 0.4 mg/betanin equivalents/L and 19.6 ± 0.6 mg/betanin equivalents/100 g, respectively) and betaxanthins (41.7 ± 0.7 mg/indicaxanthin equivalents/L and 7.5 ± 0.2 mg/indicaxanthin equivalents/100 g, respectively). Despite high betanin contents in both BTJ (~194 mg) and BF (~66 mg), betanin could not be detected in the plasma at any time point post-ingestion. Plasma NOx was elevated above baseline for 8 h after consuming BTJ and 5 h after BF (P < 0.05).
Conclusions
These data reveal that BTJ and BF are rich in phytonutrients and may provide a useful means of increasing plasma NOx bioavailability. However, betanin, the major betalain in beetroot, showed poor bioavailability in plasma
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An exploration of sequence specific DNA-duplex/pyrene interactions for intercalated and surface-associated pyrene species. Technical progress report
No full textThe use of both short (5-atom) and long (12-atom) covalent linking chains to attach, respectively, a pyrenesulfonate or a pyrenebutyrate moiety to a central region of a DNA duplex allows construction of DNA-duplex/pyrene assemblies of two types. Long linking chains permit pyrene to intercalate within the DNA duplex, while the short chains constrain pyrene to remain in the outer-surface region of the major-groove of the duplex. Electrochemical data suggest that reductive electron-transfer (ET) quenching of photoexcited pyrene (pyrene*) labels will be most exothermic for guanosine than for the other three DNA nucleosides and that oxidative ET quenching of pyrene* will be most exothermic for thymidine than for the other three DNA nucleosides. The study combines two effects, (1) differential DNA/pyrene geometries in covalent assemblies with different length linking chains and (2) differential ET quenching reactivities among the DNA nucleotides to explore sequence specific and duplex/pyrene association specific effects on DNA-base ionization reactions. This report describes progress in synthesizing target pyrene-labeled nucleosides and oligonucleotides, in commissioning our fluorescence lifetime measurement system, and in the photochemical behavior of pyrene-labeled nucleosides, single strands of DNA, and duplexes of DNA
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An exploration of sequence specific DNA-duplex/pyrene interactions for intercalated and surface-associated pyrene species. Final report, May 1, 1993--December 31, 1996
No full textThe broad objective of this DOE sponsored work on photoinduced electron transfer (ET) within covalently modified DNA was to learn about the rates of Et among various DNA bases and commonly used organic electron donor (D) and acceptor (A) molecules. This hypothesis driven, multidisciplinary project combined skills in modified nucleic acid synthesis and in continuous and time-resolved optical spectroscopies. Covalently modified DNA chemistry as investigated in this program had two specific long term goals. The first was to use experimental and theoretical insights into the mechanisms of electron transfer (ET) reactions to design supramolecular assemblies of redox-active chromophores that function as efficient vectorial ET engines. The second was to construct oligonucleotide probes for real-time monitoring of intracellular processes involving DNA and RNA such as m-RNA expression and translocation. This research project laid the groundwork for studying ET reactions within DNA duplexes by examining the photophysics of uridine nucleosides which are covalently labeled at the 5-position with 1-pyrenyl chromophores
Absorption and excretion of elderberry (Sambucus nigra L.) anthocyanins in healthy humans
No full textPharmacokinetic variables of several dietary anthocyanins (potent natural antioxidants) following consumption of elderberry (Sambucus nigra L.) extract were evaluated in urine and plasma of six healthy volunteers. They were given a single oral dose of either 30 ml (278 mg total anthocyanins) or 200 ml (1852 mg total anthocyanins) of a commercially available elderberry extract. Within 7 h, the fraction of orally administered total anthocyanins (calculated as the sum of cyanidin-3-sambubioside and cyanidin-3-glucoside) excreted unchanged was 0.39% and 0.27% following ingestion of 30 and 200 ml, respectively. The elimination half-life of total anthocyanins was slightly lower following the consumption of 278 mg (1.85 h) than that after the consumption of 1852 mg (2.57 h). The renal clearance (median) of total anthocyanins was 196 and 169 ml/min, respectively. The peak and average systemic exposure to the major elderberry anthocyanidin glycosides in plasma as well as their renal excretion exhibited approximate dose-proportional characteristics within the administered range. The low dose-normalized area under the concentration-time curve (AUC) and the fraction of orally administered anthocyanins recovered unchanged in urine indicate a low bioavailability of these compounds
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Laser studies of radiationless decay mechanisms in Os/sup 2 +///sup 3 +/ polypyridine complexes
No full textThe lowest energy excited states in Os(II) polypyridine complexes are of a metal-to-ligand charge transfer (MLCT) type and live for 10 to 40 ..mu..s at 4.2/sup 0/K. The long wavelength absorptions in the visible region of the spectrum in Os(III) polypyridine complexes arise from ligand-to-metal charge transfer (LMCT) transitions and do not produce detectable luminescence. This suggests that these LMCT states are very short lived. Results of picosecond absorption studies on the lifetimes the LMCT states in OsL/sub 3//sup 3 +/ complexes (L = 2,2'-bipyridine(bpy) or 1,10-phenanthroline(phen)) as functions of temperature and isotopic substitution are reported. The LMCT lifetimes at low temperature are contrasted with the low temperature lifetimes of the MLCT states of OsL/sub 3//sup 2 +/ complexes and both are examined from the perspective of a coarse-grained radiationless decay theory developed by Englman, R. and Jortner, J. (Molec. Phys. 1970, 18, 145). The agreement between experiment and theory suggests the following: (1) Englman and Jortner's theory of radiationless decay is useful for inorganic as well as organic systems; (2) mid-frequency (1300 to 1600 cm/sup -1/) vibrations are the important energy accepting modes for radiationless decay of the charge transfer excited states of OsL/sub 3//sup 2 +///sup 3 +/ complexes and; (3) the 10/sup 5/-10/sup 6/ difference in lifetimes between the MLCT states of OsL/sub 3//sup 2 +/ complexes and the LMCT states of OsL/sub 3//sup 3 +/ complexes is largely due to the difference in their energy gaps
Pharmacokinetics of anthocyanidin-3-glycosides following consumption of Hibiscus sabdariffa L. extract
No full textPharmacokinetic parameters of several dietary anthocyanins following consumption of Hibiscus sabdariffa L. extract were determined in 6 healthy volunteers. Subjects were given a single oral dose of 150 mL of Hibiscus sabdariffa L. extract yielding 62.6 mg of cyanidin-3-sambubioside, 81.6 mg of delphindin-3-sambubioside, and 147.4 mg of total anthocyanins (calculated as cyanidin equivalents). Within 7 hours, the urinary excretion of cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins (ie, the sum of all quantifiable anthocyanidin glycosides) was 0.016%, 0.021%, and 0.018% of the administered doses, respectively. Maximum excretion rates were determined at 1.5 to 2.0 hours after intake. The dose-normalized plasma area under the curve estimates were 0.076, 0.032, and 0.050 ng•h/mL/mg for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The dose-normalized Cmax estimates were 0.036, 0.015, and 0.023 ng/mL/mg in the same sequence. They were reached each at 1.5 hours (median) after intake. The geometric means of t1/2 were 2.18, 3.34, and 2.63 hours for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The urinary excretion of intact anthocyanins was fast and appeared to be monoexponential. To evaluate the contribution of anthocyanins to the health-protecting effects of Hibiscus sabdariffa L. extract, it will be necessary to perform further studies on both the intact glycosides and their in vivo metab-olites or conjugates in human plasma and urine
T-SP1: a novel serine protease-like protein predominantly expressed in testis
No full textHere, we describe a novel member in the group of membrane-anchored chymotrypsin (S1)-like serine proteases, namely testis serine protease 1 (T-SP1), as it is principally expressed in testis tissue. The human T-SP1 gene encompasses 28.7 kb on the short arm of chromosome 8 and consists of seven exons. Rapid amplification of cDNA ends ( RACE) experiments revealed that due to alternative splicing three different variants (T-SP1/1, -2, -3) are detectable in testis tissue displaying pronounced heterogeneity at their 3'-end. T-SP1/1 consists of an 18 amino acid signal peptide and of a 49 amino acid propeptide. The following domain with the catalytic triad of His(108), Asp(156), and Ser(250) shares sequence identities of 42% and 40% with the blood coagulation factor XI and plasma kallikrein, respectively. Only T-SP1/1 contains a hydrophobic part at the C-terminus, which provides the basis for cell membrane anchoring. Using a newly generated polyclonal anti-T-SP1 antibody, expression of the T-SP1 protein was found in the Leydig and Sertoli cells of the testis and in the epithelial cells of the ductuli efferentes. Notably, T-SP1 protein was also detectable in prostate cancer and in some ovarian cancer tissues, indicating tumor-related synthesis of T-SP1 beyond testis tissue
The function and origin of the CD4+ T cell in the classical Hodgkin lymphoma microenvironment
No full textPhDClassical Hodgkin lymphoma (CHL) is a germinal centre B cell malignancy where the bulk of the tumour comprises a non-clonal immune infiltrate enriched for CD4+ T cells. The role of these cells in the pathophysiology of CHL is poorly understood. Biomarkers predictive of clinical outcome in CHL are limited. This thesis examines microenvironment biomarkers with the goal of identifying the 10-20% of patients who are not cured by conventional therapy, and also investigates the function of the CD4+ T cell in CHL.
The prognostic power of FOXP3, a marker of regulatory T cells, CD68, a macrophage marker and CD20, a B cell marker, is validated in a new patient cohort and for the first time CD68 and FOXP3 are combined in a statistically robust scoring system. The data presented challenge the assumption that the microenvironment is Th2-polarised or senescent and demonstrates relative over-expression of T-BET, a Th1 marker and under-expression of PD1, a marker of senescence/exhaustion, with little evidence for Th2 marker expression. A cytokine-enriched in vitro culture system was developed demonstrating superior proliferation and longevity of CHL-derived T cells compared to non-malignant tissue-derived controls. These cells sustain expression of markers associated with proliferation and longevity (e.g. CD27, CD28) and remain functional (express cytokines) for many weeks. A panel of CD4+ T cell-specific markers was determined capable of differentiating CHL-derived from non-malignant or non-Hodgkin lymphoma-derived CD4+ T cells, in which markers of central memory (CD62L and CCR7) and early activation (CD69) are over-represented and markers of senescence (CD57 and PD1) are under-represented. Cytokine profiles were found to resemble Th1 (expression of IL2, IFN- and TNF expression) rather than Th2 (IL4, IL13, IL21, IL10 and IL6) responses.
The data presented confirm a new prognostic biomarker signature and show a Th1 rather than Th2-dominated microenvironment enriched for cytokine-secreting functional effector CD4+ T cells and long-lived, proliferative cells resembling central memory cells rather than hypoproliferative, anergic, non-functional T cells
Induced carotenoid accumulation in Dunaliella salina and Tetraselmis suecica by plant hormones and UV-C radiation
No full textCarotenoids prevent different degenerative diseases and improve human health. Microalgae are commercially exploited for carotenoids, including astaxanthin and β-carotene. Two commercially important microalgae, Dunaliella salina and Tetraselmis suecica, were treated with plant hormones salicylic acid (SA) and methyl jasmonate (MJ), or by UV-C radiation (T. suecica only) and a combination thereof. Significant increases in total carotenoids were found for D. salina and T. suecica after treatment with MJ (10 μmol/L) and SA (70–250 μmol/L), respectively. T. suecica also had significant increases in total carotenoids following UV-C radiation compared to control cultures. Among the carotenoids, lutein was the highest induced carotenoid. A combination of these two treatments also showed a significant increase in total carotenoids and lutein for T. suecica, when compared to controls. Plant hormones and UV-C radiation may be useful tools for increasing carotenoid accumulation in green microalgae although the responses are species- and dose-specific and should be trialed in medium to large scale to explore commercial production
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