35,914 research outputs found
The impact of chronic multimorbidity and disability on functioning and survival. A community-based, longitudinal study
No full textAbstract. Marengoni A, von Strauss E, Rizzuto D,
Winblad B, Fratiglioni L (Aging Research Center,
Gerontology Research Center and Karolinska Institutet,
Stockholm, Sweden, and University of Brescia
and Civili Hospital, Brescia, Italy). The impact of
chronic multimorbidity and disability on functional
decline and survival in elderly persons. A communitybased,
longitudinal study. J Intern Med 2009;
265: 288–295.
Objective. We aimed to disentangle the effect of
chronic multimorbidity and disability on 3-year functional
decline and survival in the elderly.
Design. Prospective cohort study with a mean of follow-
up of 2.8 years.
Setting. Swedish elderly persons from the Kungsholmen
Project (1987–2000).
Subjects. A total of 1099 subjects, 77–100 years old,
living in the community and institutions.
Main outcome measurements. Medical diagnoses (based
on clinical examination, drug use, medical records
and blood tests), and functional assessment (according
to Katz Index) at baseline were investigated in relation
to functional decline and death occurring during
follow-up.
Results. At baseline, 12.1% of participants had disability,
and 52.3% were affected by multimorbidity. During
follow-up, 363 persons died and 85 worsened in
functioning. The number of chronic conditions incrementally
increased the risk of functional decline [hazard
ratio (HR) increased from 1.5 in subjects with one
disease to 6.2 in persons with 4+ diseases]. However,
this was not the case for mortality, as the HR of death
was the same for people with one disease as well as 4+
diseases (HR = 2.3). Baseline disability had the highest
impact on survival, independently of number of diseases
[HR = 8.1; 95% confidence interval (CI) = 4.8–
13.7 in subjects with one disease and HR = 7.7; 95%
CI = 4.7–12.6 in those with 2+ diseases].
Conclusions. In the elderly subjects, chronic disability
rather than multimorbidity emerged as the strongest
negative prognostic factor for functionality and
survival
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Status spongiosus of rat central nervous system induced by actinomycin D
No full textThe effect on central myelin of Actinomycin D, an RNA--and, secondarily, a protein-synthesis inhibitor, has been studied by light and electron microscopy. The intracranial injection of this drug produced an extensive status spongiosus of the white matter in the cerebrum, cerebellum, brain stem and optic nerve within 48 h. The status spongiosus was due to vacuole formation within the myelin sheath and to enlargement of the extracellular space. Three types of vacuoles were observed: (a) the most common varieties formed between the inner tongue and the remainder of the myelin sheath; (b) a second variety formed by enlargement of the periaxonal space with separation of the axon from its myelin sheath, and (c) a less common type of vacuolization was due to splitting of the myelin lamellae at the interperiod line to form large intramyelinic vacuoles. Myelinic vacuoles were preceded by nuclear and cytoplasmic changes in oligodendrocytes, which included nucleolar segregation, disaggregation, and diminution in number of ribosomes. These changes were similar to those previously reported in a variety of cells exposed to Actinomycin D. It is suggested that myelin vacuoles result secondarily from the Actinomycin D inhibitory effect on oligodendroglial RNA--and protein-synthesis, rather than from a direct effect of this drug on the myelin sheath
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
T-cell cytotoxicity of human Schwann cells: TNFalpha promotes fasL-mediated apoptosis and IFN gamma perforin-mediated lysis
No full textThe ability of resident cells to induce apoptosis of invading immune cells is a major regulatory factor operating in immune-privileged tissues, including the nervous system. We investigated the cellular and molecular factors participating in modulation of immune response in peripheral nerves, focusing on two cytotoxic pathways: fas ligand (fasL) and perforin. fasL and perforin expression was found by immunochemistry on Schwann cells (Sc) in nerve biopsies from patients with chronic inflammatory demyelinating polyneuritis and on human Sc cultures. Treatment of Sc with tumor necrosis factor (TNF) alpha and interferon (IFN) gamma upregulated the expression of both molecules. In a coculture model, Sc exposed to TNFalpha or IFN gamma were able to induce both apoptotic and lytic injury of T-lymphocytes. Inactivation of fasL with the neutralizing antibody NOK-2 abolished T-cell apoptosis induced by Sc treated with TNFalpha, but not by Sc treated with IFN gamma. Conversely, T-cell lysis was significantly decreased when IFN gamma-activated Sc were treated with concanamycin A, which inhibited perforin release. At variance with T-lymphocytes, B-cells were less sensitive to cytokine-treated Sc toxicity. Thus, Sc exposed to inflammatory cytokines have the capacity of inducing selective damage of T-lymphocytes and have the potential of regulating the immune response in the peripheral nervous system
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Elevati livelli plasmatici delle forme di vitamina E e riduzione del rischio di malattia di Alzheimer in età avanzata
No full textIntroduction. This paper investigates the association between plasma levels of eight vitamin E forms and incidence of Alzheimer’s disease (AD) among oldestold individuals in a population-based setting.
Methods. A dementia-free sample of 232 subjects aged 80+ years, derived from the Kungsholmen Project, was followed-up to 6 years to detect incident AD. Plasma levels of vitamin E (a-, b-, g-, and d-tocopherol; a-, b-, g-, and d-tocotrienol) were measured at baseline. Vitamin E forms-AD association was analyzed with Cox proportional hazard model after adjustment for several potential confounders.
Results. Subjects with plasma levels of total tocopherols, total tocotrienols or total vitamin E in the highest tertile had a reduced risk of developing AD in comparison to persons in the lowest tertile. Multi-adjusted relative risk (RRs) and 95% confidence interval (CI) were 0.55 (0.32-0.94) for total tocopherols, 0.46 (0.23-0.92) for total tocotrienols, and 0.55 (0.32-0.94) for total vitamin E. When considering each vitamin E form, the risk of developing Alzheimer’s disease was reduced only in association with high plasma levels of b-tocopherol (RR: 0.62, 95% CI 0.39-0.99), whereas a-tocopherol, a- and b-tocotrienol showed only a marginally significant effect in the multiadjusted model [RR (95% CI): atocopherol: 0.72 (0.48-1.09); a-tocotrienol: 0.70 (0.44-1.11); b-tocotrienol: 0.69 (0.45-1.06)].
Discussion. High plasma levels of vitamin E are associated with a reduced risk of AD in advanced age. The neuroprotective effect of vitamin E seems to be related to the combination of different forms, rather than to a-tocopherol alone, whose efficacy in interventions against AD is currently debated
Nonlocal field correlations and dynamical Casimir-Polder forces between one excited- and two ground-state atoms
No full textThe problem of nonlocality in the dynamical three-body Casimir-Polder interaction between an initially excited and two ground-state atoms is considered. It is shown that the nonlocal spatial correlations of the field emitted by the excited atom during the initial part of its spontaneous decay may become manifest in the three-body interaction. The observability of this new phenomenon is discussed
Causality, nonlocality and three-body Casimir-Polder energy between three ground-state atoms
No full textThe problem of relativistic causality in the time-dependent three-body Casimir–Polder interaction energy between three atoms, initially in their bare ground state, is discussed. It is shown that the non-locality of the spatial correlations of the electromagnetic field emitted by the atoms during their dynamical selfdressing
may become manifest in the dynamical three-body Casimir–Polder interaction energy between the three atoms
Synapses and malnutrition: quantitative ultrastructural study of rat cerebral cortex
No full textIn a previous study we have found that synaptosomal fractions from cerebral cortex of 24-day-old rats malnourished from late gestation yielded more protein and higher enzyme activities than the controls, suggesting that presynaptic endings may be relatively "spared" during malnutrition. In order to explore further the effect of malnutrition on presynaptic endings, we have carried out a quantitative ultrastructural study of the lamina pyramidalis from the somatosensory cortex of rats identical in age and method of malnutrition to those used in the previous study. The fractional area of the cortex occupied by cell bodies was 53% larger in the malnourished animals than in the controls. This increase was due to a higher density rather than a larger size of the cell bodies. Neurons accounted for almost all the increase of cellularity while no conclusion could be reached for the glia. The fractional area occupied by neuropil was decreased by 7.4%. The fractional area of the neuropil occupied..
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