Age identity, self-rated health, and life satisfaction among older adults in Dakar, Senegal

The objectives of this quantitative study were to (1) ascertain to what extent older adults aged 50 and above feel and desire to be younger than their age, and classify themselves as young versus old; (2) compare these patterns with those found among other cross-cultural populations; and (3) assess the extent to which self-rated health and life satisfaction predict age identities. This study was carried out on a sample of 500 dwellers of the Senegalese capital aged 50 and older. This sample was constructed using the quota method to strive for representativeness. Most of the respondents wanted to be younger than their chronological age (51.8 %), but only 27.8 % felt younger than they were. Moreover, 80 % of the sample claimed to be old. Self-rated health predicted felt age and the feeling of being old. Furthermore, the less-satisfied Dakar residents were with their life, the younger they wanted to be. We first discuss our results in a comparative perspective focused on how orientations toward individualism and collectivism could be related to age identity, and on demographic characteristics of the Senegalese population—where life expectancy is 59.3 years old. We then analyze the relevance of age identity dimensions as indicators of successful aging in Dakar.     

Chronic exposure to low concentrations of strontium 90 affects bone physiology but not the hematopoietic system in mice

The aim of this work was to delineate the effects of chronic ingestion of strontium 90 (⁹⁰Sr) at low concentrations on the hematopoiesis and the bone physiology. A mouse model was used for that purpose. Parent animals ingested water containing 20 kBq l^?1 of ⁹⁰Sr two weeks before mating. Offspring were then continuously contaminated with ⁹⁰Sr through placental transfer during fetal life, through lactation after birth and through drinking water after weaning. At various ages between birth and 20 weeks, animals were tested for hematopoietic parameters such as blood cell counts, colony forming cells in spleen and bone marrow and cytokine concentrations in the plasma. However, we did not find any modification in ⁹⁰Sr ingesting animals as compared with control animals. By contrast, the analysis of bone physiology showed a modification of gene expression towards bone resorption. This was confirmed by an increase in C‐telopeptide of collagen in the plasma of ⁹⁰Sr ingesting animals as compared with control animals. This modification in bone metabolism was not linked to a modification of the phosphocalcic homeostasis, as measured by calcium, phosphorus, vitamin D and parathyroid hormone in the blood. Overall these results suggest that the chronic ingestion of ⁹⁰Sr at low concentration in the long term may induce modifications in bone metabolism but not in hematopoiesis. Copyright © 2012 John Wiley & Sons, Ltd.     

Distinct surrogate markers for protection against Plasmodium falciparum infection and clinical malaria identified in a Senegalese community after radical drug cure

Plasmodium falciparum expresses many antigens, which elicit various immune responses in exposed individuals, but no simple surrogate marker for protection has yet been developed. In this prospective survey, we looked for immune responses predictive of protection at various stages of progression from parasite inoculation to onset of disease. We studied 110 Senegalese volunteers from an area in which malaria is mesoendemic after they had received eradication therapy. We evaluated 4 protection-related outcomes (reappearance of parasitemia, duration of asymptomatic carriage, time to first clinical episode, and incidence of clinical episodes) in terms of levels of immunoglobulin G (IgG) against 3 crude parasite extracts and 5 conserved antigens during a 5-month period. Kaplan-Meier estimates and age-adjusted regression models showed these 4 outcomes to be associated with different patterns of IgG response to PfEMP3-cl5 (derived from P. falciparum erythrocyte membrane protein 3), PfEB200, MSP-1(19) (derived from merozoite surface protein-1), [NANP]10, infected red blood cell membrane, and merozoite and schizont extracts. It should, therefore, be possible to develop surrogate markers for each end point on the basis of IgG response to a limited number of conserved antigens.     

Differential vesicular distribution and trafficking of MMP‐2, MMP‐9, and their inhibitors in astrocytes

Astrocytes play an active role in the central nervous system and are critically involved in astrogliosis, a homotypic response of these cells to disease, injury, and associated neuroinflammation. Among the numerous molecules involved in these processes are the matrix metalloproteinases (MMPs), a family of zinc‐dependent endopeptidases, secreted or membrane‐bound, that regulate by proteolytic cleavage the extracellular matrix, cytokines, chemokines, cell adhesion molecules, and plasma membrane receptors. MMP activity is tightly regulated by the tissue inhibitors of MMPs (TIMPs), a family of secreted multifunctional proteins. Astrogliosis in vivo and astrocyte reactivity induced in vitro by proinflammatory cues are associated with modulation of expression and/or activity of members of the MMP/TIMP system. However, nothing is known concerning the intracellular distribution and secretory pathways of MMPs and TIMPs in astrocytes. Using a combination of cell biology, biochemistry, fluorescence and electron microscopy approaches, we investigated in cultured reactive astrocytes the intracellular distribution, transport, and secretion of MMP‐2, MMP‐9, TIMP‐1, and TIMP‐2. MMP‐2 and MMP‐9 demonstrate nuclear localization, differential intracellular vesicular distribution relative to the myosin V and kinesin molecular motors, and LAMP‐2‐labeled lysosomal compartment, and we show vesicular secretion for MMP‐2, MMP‐9, and their inhibitors. Our results suggest that these proteinases and their inhibitors use different pathways for trafficking and secretion for distinct astrocytic functions. © 2009 Wiley‐Liss, Inc.