919 resultados para Life-span


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Clinical and experimental observations suggest that platelet function deteriorates quickly with cell age. However, efforts to define age-dependent alterations have detected only modest biochemical changes occurring late in the cell life span. In this report, we demonstrate two significant alterations of the collagen response occurring during in vivo aging of canine platelets: a progressive increase in the EC50 for collagen types I, III and V and the emergence of a population of aged platelets which are refractory to collagen. Experiments with convulxin, a specific agonist for the collagen receptor glycoprotein VI (GPVI), also demonstrate an age-dependent decline in activation and the appearance of a non-reactive, aged population as observed with native collagens. Our studies indicate that canine platelets have two distinct binding levels for FITC-labeled convulxin and that the higher binding level disappears upon cell aging. During these studies one dog (#428) was identified whose platelets not only failed to demonstrate an age-dependent decrease in convulxin reactivity but also maintained a high convulxin-binding ability throughout their otherwise normal life span. Transfusion of biotinylated platelets from control dogs into dog #428 showed that the expected changes in collagen response and GPVI function did not occur in the transfused platelets. These observations demonstrate that the canine platelet response towards collagen is strongly dependent upon cell-age and suggest that this functional decline is at least partly due to an extrinsic-mediated alteration, possibly proteolytic, of GPVI.

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In the resolution of inflammatory responses, neutrophils rapidly undergo apoptosis. We describe a new proapoptotic pathway in which cathepsin D directly activates caspase-8. Cathepsin D is released from azurophilic granules in neutrophils in a caspase-independent but reactive oxygen species-dependent manner. Under inflammatory conditions, the translocation of cathepsin D in the cytosol is blocked. Pharmacological or genetic inhibition of cathepsin D resulted in delayed caspase activation and reduced neutrophil apoptosis. Cathepsin D deficiency or lack of its translocation in the cytosol prolongs innate immune responses in experimental bacterial infection and in septic shock. Thus, we identified a new function of azurophilic granules that is in addition to their role in bacterial defense mechanisms: to regulate the life span of neutrophils and, therefore, the duration of innate immune responses through the release of cathepsin D.

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Irreversible, nonenzymatic glycation of the haemoglobin A beta chain leads to the formation of haemoglobin A1c (HbA1c), a stable minor haemoglobin component with enhanced electrophoretic mobility. The rate of formation of HbA1c is directly proportional to the ambient glucose concentration. HbA1c is commonly used to assess long-term blood glucose control in patients with diabetes mellitus, because the HbA1c value has been shown to predict the risk for the development of many of the chronic complications in diabetes. There are currently four principal glycohaemoglobin assay techniques (ion-exchange chromatography, electrophoresis, affinity chromatography and immunoassays) and over 20 methods that measure different glycated products. The ranges indicating good and poor glycaemic control can vary markedly between different assays. At the moment values differ between methodologies and even between different laboratories using the same methodology. Optimal use of HbA1c testing requires standardisation. There is progress towards international standardisation and improved precision of HbA1c which will lead to all assays reporting results in a standardised way. Clinicians ordering HbA1c testing for their patients should be aware of the type of assay method used, the reference interval, potential assay interferences (e.g. haemoglobinopathies, chronic alcohol ingestion, carbamylation products in uraemia) and assay performance. And they should know that a variety of factors have been shown to directly influence HbA1c values, e.g. iron deficiency anaemia, chronic renal failure and shortened red blood cell life span.

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BACKGROUND: Many studies confirm that noncompliance or poor compliance is one of the great problems in health care as it results in waste of resources and funds. METHODS: This overview includes literature on heart, liver, and kidney transplants with emphasis on heart transplantation in adult and pediatric transplant patients and addresses the following variables as potential predictors of postoperative compliance problems: demographic variables (age, marital status, gender) psychological variables (anxiety, denial) psychiatric disorders (major depression, anxiety, and personality disorders), poor social support, pretransplant noncompliance, obesity, substance abuse, and health-related variables (distance from transplant center, indication for transplantation, required pretransplant assist device). Relevant studies on these topics that were conducted up to 1999 are included and discussed in this overview. The most important results are presented in tables. RESULTS: Unfortunately, there has not been any systematic and comprehensive review of the literature on predictors of noncompliance in organ transplant patients so far. With organ transplantation noncompliance impairs both life quality and life span as it is a major risk factor for graft rejection episodes and is responsible for up to 25% of deaths after the initial recovery period. Therefore, it might be assumed that well-informed transplant patients are a highly motivated group whose compliance is just as high. This is not the case. However, even when graft loss means loss of life as in heart or liver transplantation, noncompliance occurs. To best select potential organ recipients, it would be ideal if patients who are very likely to show noncompliant behavior could be identified already before being transplanted. CONCLUSION: The literature overview shows the necessity of preoperative psychosocial screening regarding predictors for posttransplant noncompliance.

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The contribution of basophils in allergic disease and other Th2-type immune responses depends on their persistence at sites of inflammation, but the ligands and molecular pathways supporting basophil survival are largely unknown. The comparison of rates of apoptosis and of the expression of antiapoptotic proteins in different human granulocyte types revealed that basophils have a considerably longer spontaneous life span than neutrophils and eosinophils consistent with high levels of constitutive Bcl-2 expression. Interleukin-3 (IL-3) is the only ligand that efficiently protects basophils from apoptosis as evidenced by screening a large number of stimuli. IL-3 up-regulates the expression of the antiapoptotic proteins cIAP2, Mcl-1, and Bcl-X(L) and induces a rapid and sustained de novo expression of the serine/threonine kinase Pim1 that closely correlates with cytokine-enhanced survival. Inhibitor studies and protein transduction of primary basophils using wild-type and kinase-dead Pim1-Tat fusion-proteins demonstrate the functional importance of Pim1 induction in the IL-3-enhanced survival. Our data further indicate that the antiapoptotic Pim1-mediated pathway operates independently of PI3-kinase but involves the activation of p38 MAPK. The induction of Pim1 leading to PI3-kinase-independent survival as described here for basophils may also be a relevant antiapoptotic mechanism in other terminally differentiated leukocyte types.

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If the profession of social work is to have a future we must know where it came from, and the series of portraits of our pioneers is one of the paths into the origins of that profession. I feel grateful to the publishers for this online-journal and also honoured to be asked to continue the series on pioneers in social work. I gladly comply because, in connection with my research on Alice Salomon and other social workers who were expelled from Germany and other Nazi-occupied territories (Wieler1989 and 1995) I had the pleasure and privilege of meeting and interviewing Walter Friedländer shortly before he passed away. It is years ago that I visited him in his home among stacks of books and piles of papers. My memories are vivid. I still see his sparkling eyes and hear his soft voice with a very heavy German accent. I was most impressed by his memory of historical events and people which, it seemed, only a large hard-drive could retain these days. Now, I wish I had asked more questions but instead, we will have to rely largely on primary and secondary literature and box upon box of archival materials. I draw heavily on the comprehensive German and Jewish Intellectual Emigré Collection (http://library.albany.edu/speccoll/findaids/ger003.htm) which consists of nearly 50 cubic feet and another collection of the German Central Institute („Deutsches Zentralinstitut für Soziale Fragen-DZI“) in Berlin (www.dzi.de). Some of the more current archival materials were lost in a flood, and much of Friedländer’s early memorabilia up to 1933 was lost in Germany. There are also internet resources with widely differing information. I hope that I will not have overlooked too much in order to do justice to this remarkable pioneer and colleague. In order to appreciate and pay tribute to Walter Friedländer and his contributions we will have to reconsider the historical and international context of more than the 93 years of his life span: the German Monarchy, the Weimar Republic, Nazi-Fascism, Swiss, French and American exile and numerous visits to other countries.

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Background: Basophils constitute a rare leukocyte population known for their effector functions in inflammation and allergy, as well as more recently described immunoregulatory roles. Besides their low frequency, functional analysis of basophils is hindered by a short life span, inefficient ex vivo differentiation protocols, and lack of suitable cell models. A method to produce large quantities of basophils in vitro would facilitate basophil research and constitute a sought-after tool for diagnostic and drug testing purposes. Methods: A method is described to massively expand bone marrow–derived basophils in vitro. Myeloid progenitors are conditionally immortalized using Hoxb8 in the presence of interleukin-3 (IL-3) and outgrowing cell lines selected for their potential to differentiate into basophils upon shutdown of Hoxb8 expression. Results: IL-3-dependent, conditional Hoxb8-immortalized progenitor cell lines can be expanded and maintained in culture for prolonged periods. Upon shutdown of Hoxb8 expression, near-unlimited numbers of mature functional basophils can be differentiated in vitro within six days. The cells are end-differentiated and short-lived and express basophil-specific surface markers and proteases. Upon IgE- as well as C5a-mediated activation, differentiated basophils release granule enzymes and histamine and secrete Th2-type cytokines (IL-4, IL-13) and leukotriene C4. IL-3-deprivation induces apoptosis correlating with upregulation of the BH3-only proteins BCL-2-interacting mediator of cell death (BIM) and p53 upregulated modulator of apoptosis (PUMA) and downregulation of proviral integration site for Moloney murine leukemia virus 1 kinase (PIM-1). Conclusion: A novel method is presented to generate quantitative amounts of mouse basophils in vitro, which moreover allows genetic manipulation of conditionally immortalized progenitors. This approach may represent a useful alternative method to isolating primary basophils.

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RecA in Escherichia coli and it's homologue, ScRad51 in Saccharomyces cerevisiae, play important roles in recombinational repair. ScRad51 homologues have been discovered in a wide range of organisms including Schizosaccharomyces pombe, lily, chicken, mouse and human. To date there is no direct evidence to describe that mouse Rad51(MmRad51) is involved in DNA double-strand break repair. In order to elucidate the role of MmRad51 in vivo, it was mutated by the embryonic stem (ES) cell/gene targeting technology in mice. The mutant embryos arrested in development shortly after implantation. There was a decrease in cell proliferation followed by programmed cell death, and trophectoderm-derived cells were sensitive to $\gamma$-radiation. Severe chromosome loss was observed in most mitotically dividing cells. The mutant embryos lived longer and developed further in a p53 mutant background; however, double-mutant embryonic fibroblasts failed to proliferate in tissue culture, reflecting the embryos limited life span. Based on these data, MmRad51 repairs DNA damage induced by $\gamma$-radiation, is needed to maintain euplody, and plays an important role in proliferating cells.^ Ku is a heterodimer of 70 and 80 kDs subunit, which binds to DNA ends and other altered DNA structures such as hairpins, nicks, and gaps. In addition, Ku is required for DNA-PK activity through a direct association. Although the biochemical properties of Ku and DNA-PKcs have been characterized in cells, their physiological functions are not clear. In order to understand the function of Ku in vivo, we generated mice homozygous for a mutation of the Ku80 gene. Ku80-deficient mice, like scid mice, showed severe immunodeficiency due to a impairment of V(D)J recombination. Mutant mice were semiviable and runted, cells derived from mutant embryos displayed hypersensitivity to $\gamma$-radiation, a decreased growth rate, a slow entry into S phase, altered colony size distributions, and a short life span. Based on these results, mutant cells and mice appeared to prematurely age. ^

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Background Research results from large, national population-based studies investigating gender differences in weight dissatisfaction and disordered eating across the adult life span are still limited. Gender is a significant factor in relation to weight dissatisfaction and disordered eating. However, the reasons for gender differences in these conditions are still poorly understood. The aim of this study was to examine gender differences in weight dissatisfaction and disordered eating in the general Swiss adult population and to identify gender-specific risk factors. Methods The study population consisted of 18156 Swiss adults who completed the population-based Swiss Health Survey 2007. Self-reported weight dissatisfaction, disordered eating and associated risk factors were assessed. In order to examine whether determinants of weight dissatisfaction and disordered eating (dieting to lose weight, binge eating, and irregular eating) differ in men and women, multivariate logistic regressions were applied separately for women and men. Results Although more men than women were overweight, more women than men reported weight dissatisfaction. Weight category, smoking status, education, and physical activity were significantly associated with weight dissatisfaction in men and women. In women, nationality and age were also significant factors. Gender-specific risk factors such as physical activity or weight category were identified for specific disordered eating behaviours. Conclusions The results suggest that gender specific associations between predictors and disordered eating behaviour should be considered in the development of effective prevention programs against disordered eating.

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The p62/SQSTM1 adapter protein has an important role in the regulation of several key signaling pathways and helps transport ubiquitinated proteins to the autophagosomes and proteasome for degradation. Here, we investigate the regulation and roles of p62/SQSTM1 during acute myeloid leukemia (AML) cell maturation into granulocytes. Levels of p62/SQSTM1 mRNA and protein were both significantly increased during all-trans retinoic acid (ATRA)-induced differentiation of AML cells through a mechanism that depends on NF-κB activation. We show that this response constitutes a survival mechanism that prolongs the life span of mature AML cells and mitigates the effects of accumulation of aggregated proteins that occurs during granulocytic differentiation. Interestingly, ATRA-induced p62/SQSTM1 upregulation was impaired in maturation-resistant AML cells but was reactivated when differentiation was restored in these cells. Primary blast cells of AML patients and CD34(+) progenitors exhibited significantly lower p62/SQSTM1 mRNA levels than did mature granulocytes from healthy donors. Our results demonstrate that p62/SQSTM1 expression is upregulated in mature compared with immature myeloid cells and reveal a pro-survival function of the NF-κB/SQSTM1 signaling axis during granulocytic differentiation of AML cells. These findings may help our understanding of neutrophil/granulocyte development and will guide the development of novel therapeutic strategies for refractory and relapsed AML patients with previous exposure to ATRA.

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Loss can be seen as a normative life event; nevertheless for most individuals, the experience of the loss of a loved one is extremely stressful. The grief reaction is universal but shaped by cultural norms and individual expectations; grief may also become a serious health problem. The aim of this article is to review the consequences of grief as well as explanations and treatment of complicated grief disorder. Five areas are identified to be of importance to clinicians and researchers: (1) grief reactions, (2) models of grief, (3) bereavement across the life span, (4) diagnostic criteria, and (5) treatment for complicated grief.

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Data from two large longitudinal studies were used to analyze reciprocal relations between self-esteem and depressive symptoms across the adult life span. Study 1 included 1,685 participants aged 18 to 96 years assessed 4 times over a 9-year period. Study 2 included 2,479 participants aged 18 to 88 years assessed 3 times over a 4-year period. In both studies, cross-lagged regression analyses indicated that low self-esteem predicted subsequent depressive symptoms, but depressive symptoms did not predict subsequent levels of self-esteem. This pattern of results replicated across all age groups, for both affective–cognitive and somatic symptoms of depression, and after controlling for content overlap between the self-esteem and depression scales. The results suggest that low self-esteem operates as a risk factor for depressive symptoms at all phases of the adult life span.

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The authors examined the development of self-esteem from young adulthood to old age. Data came from the Americans’ Changing Lives study, which includes 4 assessments across a 16-year period of a nationally representative sample of 3,617 individuals aged 25 years to 104 years. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the adult life span, increasing during young and middle adulthood, reaching a peak at about age 60 years, and then declining in old age. No cohort differences in the self-esteem trajectory were found. Women had lower self-esteem than did men in young adulthood, but their trajectories converged in old age. Whites and Blacks had similar trajectories in young and middle adulthood, but the self-esteem of Blacks declined more sharply in old age than did the self-esteem of Whites. More educated individuals had higher self-esteem than did less educated individuals, but their trajectories were similar. Moreover, the results suggested that changes in socioeconomic status and physical health account for the decline in self-esteem that occurs in old age.

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Spirituality is a travelling concept among different disciplines. As for psychology, spirituality has long been a neglected topic – especially in the academic context. However, during the last dec-ade there has been an increase of theoretical and empirical work, mainly emerging from positive and life-span developmental psychology. This research focuses spirituality either as an element of well-being or as predictor of well-being and health (e.g. as a coping strategy), or finally as an outcome after dealing with critical life events (i.e. spiritual growth). This knowledge has an impact on spiritual care – and vice-versa spiritual care – as a growing inter- and transdisciplinary field – has an impact on clinical psychological practice.

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Childhood traumatic events may lead to long-lasting psychological effects and contribute to the development of complex posttraumatic sequelae. These might be captured by the diagnostic concept of complex posttraumatic stress disorder (CPTSD) as an alternative to classic posttraumatic stress disorder (PTSD). CPTSD comprises a further set of symptoms in addition to those of PTSD, namely, changes in affect, self, and interpersonal relationships. Previous empirical research on CPTSD has focused on middle-aged adults but not on older adults. Moreover, predictor models of CPTSD are still rare. The current study investigated the association between traumatic events in childhood and complex posttraumatic stress symptoms in older adults. The mediation of this association by 2 social-interpersonal factors (social acknowledgment as a survivor and dysfunctional disclosure) was investigated. These 2 factors focus on the perception of acknowledgment by others and either the inability to disclose traumatic experiences or the ability to do so only with negative emotional reactions. A total of 116 older individuals (age range = 59–98 years) who had experienced childhood traumatic events completed standardized self-report questionnaires indexing childhood trauma, complex trauma sequelae, social acknowledgment, and dysfunctional disclosure of trauma. The results showed that traumatic events during childhood were associated with later posttraumatic stress symptoms but with classic rather than complex symptoms. Social acknowledgment and dysfunctional disclosure partially mediated this relationship. These findings suggest that childhood traumatic stress impacts individuals across the life span and may be associated with particular adverse psychopathological consequences.