Prevalence of disability in a composite ≥75 year-old population in Spain: A screening survey based on the International Classification of Functioning

<p>Abstract</p> <p>Background</p> <p>The prevalence and predictors of functional status and disability of elderly people have been studied in several European countries including Spain. However, there has been no population-based study incorporating the International Classification of Functioning, Disability and Health (ICF) framework as the basis for assessing disability. The present study reports prevalence rates for mild, moderate, and severe/extreme disability by the domains of activities and participation of the ICF.</p> <p>Methods</p> <p>Nine populations surveyed in previous prevalence studies contributed probabilistic and geographically defined samples in June 2005. The study sample was composed of 503 subjects aged ≥75 years. We implemented a two-phase screening design using the MMSE and the World Health Organization-Disability Assessment Schedule 2^ndedition (WHO-DAS II, 12 items) as cognitive and disability screening tools, respectively. Participants scoring within the positive range of the disability screening were administered the full WHO-DAS II (36 items; score range: 0-100) assessing the following areas: Understanding and communication, Getting along with people, Life activities, Getting around, Participation in society, and Self-care. Each disability area assessed by WHO-DAS II (36 items) was reported according to the ICF severity ranges (No problem, 0-4; Mild disability, 5-24; Moderate disability, 25-49; Severe/Extreme disability, 50-100).</p> <p>Results</p> <p>The age-adjusted disability prevalence figures were: 39.17 ± 2.18%, 15.31 ± 1.61%, and 10.14 ± 1.35% for mild, moderate, and severe/extreme disability, respectively. Severe and extreme disability prevalence in mobility and life activities was three times higher than the average, and highest among women. Sex variations were minimal, although life activities for women of 85 years and over had more severe/extreme disability as compared to men (OR = 5.15 95% CI 3.19-8.32).</p> <p>Conclusions</p> <p>Disability is highly prevalent among the Spanish elderly. Sex- and age-specific variations of disability are associated with particular disability domains.</p

Investigation of Human Albumin-Induced Circular Dichroism in Dansylglycine

Induced circular dichroism (ICD), or induced chirality, is a phenomenon caused by the fixation of an achiral substance inside a chiral microenvironment, such as the hydrophobic cavities in proteins. Dansylglycine belongs to a class of dansylated amino acids, which are largely used as fluorescent probes for the characterization of the binding sites in albumin. Here, we investigated the ICD in dansylglycine provoked by its binding to human serum albumin (HSA). We found that the complexation of HSA with dansylglycine resulted in the appearance of an ICD band centred at 346 nm. Using this ICD signal and site-specific ligands of HSA, we confirmed that dansylglycine is a site II ligand. The intensity of the ICD signal was dependent on the temperature and revealed that the complexation between the protein and the ligand was reversible. The induced chirality of dansylglycine was susceptive to the alteration caused by the oxidation of the protein. A comparison was made between hypochlorous acid (HOCl) and hypobromous acid (HOBr), and revealed that site II in the protein is more susceptible to alteration provoked by the latter oxidant. These findings suggest the relevance of the aromatic amino acids in the site II, since HOBr is a more efficient oxidant of these residues in proteins than HOCl. The three-dimensional structure of HSA is pH-dependent, and different conformations have been characterised. We found that HSA in its basic form at pH 9.0, which causes the protein to be less rigid, lost the capacity to bind dansylglycine. At pH 3.5, HSA retained almost all of its capacity for binding to dansylglycine. Since the structure of HSA at pH 3.5 is expanded, separating the domain IIIA from the rest of the molecule, we concluded that this separation did not alter its binding capacity to dansylglycine.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Induced ellipticity as a function of dansylglycine concentration.

<p>The mixtures consisted of 15 µM HSA and increasing concentration of DG, as indicated. The results are the average and SD of experiments performed in triplicate.</p

Temperature-induced denaturation of HSA and its effect on ICD of dansylglycine.

<p>(<b>a</b>) Denaturation curve of HSA. The temperature was increased at 1°C/min, equilibrated at the target temperature for 2 min before each measurement and reversed following the same protocol; (<b>b</b>) DG was added before denaturation and the ICD spectrum measured at 25°C; (<b>c</b>) DG was added after denaturation and the ICD spectrum measured at 25°C.</p

Quenching of the intrinsic fluorescence of HSA by dansylglycine and determination of binding constant.

<p>(<b>a</b>) Emission spectra of HSA (5 µM; λ_ex = 295 nm) in the presence of dansylglycine (DG; 0–35 µM). (<b>b</b>) Stern-Volmer plots at different temperatures. (<b>c</b>) Non-linear fitting for determination of the binding constant (Ka). <b>(Table)</b> Stern-Volmer and binding constants at different temperatures. The results are the average and SD of experiments performed in triplicate.</p

Effect of pH on HSA-induced chirality in dansylglycine.

<p>(<b>a</b>) HSA (30 µM) was incubated at various pHs. (<b>b</b>) CD spectra after addition of 30 µM dansylglycine. (<b>c</b>) Absorbance spectra after addition of 30 µM dansylglycine. (<b>d</b>) Absorbance spectra of 30 µM dansylglycine alone.</p

Displacement of dansylglycine (DG) from HSA by site I and II ligands: circular dichroism studies.

<p>The mixtures consisted of 30 µM HSA, 30 µM DG, and 30 µM of naproxen (NX), ibuprofen (IB), phenylbutazone (PB), or warfarin (WF).</p

Temperature-dependent reversibility of ICD in dansylglycine.

<p>The mixtures consisted of 30 µM HSA and 30 µM DG. (<b>a</b>) The temperature was increased from 20°C to 45°C and (<b>b</b>) returned to 20°C at a rate of 0.5°C/min.</p

HSA-Induced ellipticity in dansylglycine.

<p>(<b>a</b>) Near-UV-CD and (<b>b</b>) UV-Vis spectra of dansylglycine in the presence or absence of HSA. The mixtures consisted of 30 µM HSA and 30 µM DG.</p

Effect of oxidation on HSA-induced chirality.

<p>The mixtures consisted of 30 µM HSA and (<b>a</b>) 600 µM or (<b>b</b>) 1200 µM of the oxidants. Dansylglycine (30 µM) was added after oxidation.</p