Over the years, several tools have been proposed to measure oral behaviours (OB). Recently, a smartphone-based application for ecological momentary assessment (EMA) has been introduced to collect real-time data on waking-time OB. The aim of this study was to compare the self-reported frequency of OB by means of a standardised questionnaire with that recorded with a smartphone-based application for EMA.
View Article and Find Full Text PDFThe prognostic interaction between chronic kidney disease (CKD) and cognitive impairment is still to be elucidated. We investigated the potential interaction of overall cognitive impairment or defective constructional praxis and CKD in predicting 1-year mortality among 646 older patients discharged from hospital. The estimated glomerular filtration rate (eGFR) was calculated using the Berlin Initiative Study (BIS) equation.
View Article and Find Full Text PDFBackground: The relationship between the estimated glomerular filtration rate (eGFR) and cognitive impairment may change as a function of the equation used. We aimed at investigating the association between four different eGFR equations and cognitive impairment among older hospitalized patients.
Methods: Our series consisted of 795 older patients consecutively admitted to 7 geriatric and internal medicine acute care wards.
Objective: We aimed at summarizing current evidence about mechanisms for potentially harmful effects of Proton Pump Inhibitors (PPIs).
Methods: A Pubmed search was performed, and 207 studies concerning the relationship between use of PPIs and cardiovascular diseases, kidney impairment, nutritional disorders, fractures, infections, functional decline, and mortality were selected and reviewed.
Results: PPIs may cause potentially harmful effects by several mechanisms, including endothelial dysfunction, hypomagnesemia, drug interactions, reduced absorption of selected nutrients, increased gastric microbiota and small intestine bacterial overgrowth, reduced immune response, tubular-interstitial inflammation, increased bone turnover, accumulation of amyloid in the brain.
Dolichol, an end product of the mevalonate pathway, has been proposed as a biomarker of aging, but its biological role, not to mention its catabolism, has not been fully understood. UV-B radiation was used to induce oxidative stress in isolated rat hepatocytes by the collagenase method. Effects on dolichol, phospholipid-bound polyunsaturated fatty acids (PL-PUFA) and known lipid soluble antioxidants [coenzyme Q (CoQ) and α-tocopherol] were studied.
View Article and Find Full Text PDFThere is an emerging interest in small natural molecules for their potential therapeutic use in neurodegenerative disorders like Alzheimer's disease (AD). Ferulic acid (FA), an antioxidant phenolic compound present in fruit and vegetables, has been proposed as an inhibitor of beta amyloid (Aβ) pathological aggregation. Using fluorescence and Fourier transform infrared spectroscopy, electrophoresis techniques, chromatographic analysis, and confocal microscopy, we investigated the effects of FA in the early stages of Aβ fibrillogenesis in vitro.
View Article and Find Full Text PDFIntrinsic fluorescence of peptides and proteins is extensively used to monitor their specific interactions with several natural and synthetic molecules known to have wide-ranging beneficial or detrimental effects on health. A consequence of these interactions would be a significant decrease of the fluorescence emission intensity of Tyrosine (Tyr) and/or Tryptophan (Trp) residues in the protein due to structural rearrangements of proteic microenvironment. However fluorescence quenching can be also caused by "trivial" artefacts.
View Article and Find Full Text PDFBackground: Current research has indicated that small natural compounds could interfere with β-amyloid fibril growth and have the ability to disassemble preformed folded structures. Ferulic acid (FA), which possesses both hydrophilic and hydrophobic moieties and binds to peptides/proteins, is a potential candidate against amyloidogenesis. The molecular mechanisms connected to this action have not been elucidated in detail yet.
View Article and Find Full Text PDFWe have determined the secondary structure of 1-40 β-amyloid peptides by Fourier-transform infrared spectroscopy (FTIR) and characterized the peptide photophysical properties before and after self-assembly by using intrinsic tyrosine steady-state and time-resolved fluorescence. All measurements were performed in the presence and absence of hypericin (Hyp), an exogenous natural polycyclic pigment that has been shown to inhibit fibril formation and has also been used as a fluorescent probe. We monitored the time course of the aggregation process measuring 405 nm light diffusion at 90° and used thioflavin T to reveal the presence of fibrils.
View Article and Find Full Text PDFThe conformational changes of the bovine lens protein "alpha-crystallin" have been investigated in the presence of the photosensitizer Rose Bengal (RB), in the dark as well as after visible light irradiation. Absorption and fluorescence emission spectra of RB [5 x 10(-6) M] and Fourier transform-IR spectra of alpha-crystallin [5 mg mL(-1)] were significantly altered upon RB alpha-crystallin complex formation. RB was found to bind to alpha-crystallin in a molecular pocket characterized by a low polarity, with Trp most likely involved in this interaction.
View Article and Find Full Text PDFWe present new femtosecond transient-absorption and picosecond fluorescence experiments performed on OBIP, the oxyblepharismin-binding protein believed to trigger the photophobic response of the ciliate Blepharisma japonicum. The formerly identified heterogeneity of the sample is confirmed and rationalized in terms of two independent populations, called rOBIP and nrOBIP. The rOBIP population undergoes a fast photocycle restoring the initial ground state in less than 500 ps.
View Article and Find Full Text PDFWe have performed an in vitro study to investigate the molecular basis of the aggregation kinetic of 1-40 beta-amyloid peptides (Abeta and the possibility of affecting this aggregation process using an exogenous natural polycyclic pigment, hypericin (Hyp). The effect of Hyp on the self-assembly process at different times of the aggregation kinetic has been investigated utilizing a chaperon-like molecule, alpha-crystallin. Circular dichroism and fluorescence results suggest that Hyp can associate to precursors of the mature fibrils and perturb the aggregation process through intermolecular interactions with the Abeta peptides.
View Article and Find Full Text PDFPhotochem Photobiol Sci
July 2008
The interaction of blepharismin (BP) and oxyblepharismin (OxyBP) with bovine alpha-crystallin (BAC) has been studied both by steady-state and femtosecond spectroscopy, with the aim of assessing the possible phototoxicity of these compounds toward the eye tissues. We showed that these pigments form with BAC potentially harmful ground-state complexes, the dissociation constants of which have been estimated to be 6 +/- 2 micromol L(-1) for OxyBP and 9 +/- 4 micromol L(-1) for BP. Irradiation with steady-state visible light of solutions of blepharismins in the presence of BAC proved to induce a quenching of both the pigment and the intrinsic protein fluorescences.
View Article and Find Full Text PDFTarget analysis is performed on previously published transient absorption spectra of the 200-kDa oxyblepharismin-binding protein (OBIP) thought to trigger the photophobic response of the ciliate Blepharisma japonicum. The OBIP sample is considered as heterogeneous and made of two distinct classes of chromophore-protein complexes. A so-called nonreactive class is seen to be comparable to free oxyblepharismin in organic solution.
View Article and Find Full Text PDFBlepharisma japonicum is a ciliated protozoan exhibiting a strong step-up photophobic response upon illumination. The photoreceptor chromophores responsible for this response have been identified to be hypericin-like chromophores (blepharismin and oxyblepharismin), complexed to a 200 kDa non-water-soluble protein. The present work opens up new perspectives on the primary phototransduction steps of B.
View Article and Find Full Text PDFCircular dichroism (CD) was used to study the structure of oxyblepharismin (OxyBP), the photoreceptor chromophore for the photophobic response of the blue form of Blepharisma japonicum. Both the chromophore associated to its native protein and the free chromophore in ethanol solution were investigated. CD spectra in the far-UV range indicate that OxyBP induces a slight increase in the alpha-helix content of the protein matrix.
View Article and Find Full Text PDFThe DPC offers many benefits for learners, teachers and developers involved in creation of teaching materials in photobiology. Modifications and additions can be made relatively easily. Anonymous peer review of modules, allowing them to be cited as peer reviewed publications, is likely to encourage new submissions.
View Article and Find Full Text PDFDolichol, the polyisoprenoid lipid found in all eukaryotic cells and suggested to represent a biomarker of aging, is inserted into cell membranes, also in tissues exposed to light such as the skin. A general question about its physiological role is whether dolichol may play the role of a natural barrier for the noxious components of solar radiation. In order to clarify this point, we established that dolichol is a component of human sebum and we performed an " in vitro " study of the effects of UV radiation on the spectral properties of dolichol in isopropanol.
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