Publications by authors named "Donald Palmer"

Background: Qualitative research on child sexual abuse (CSA) in youth serving organizations (YSOs) indicates that powerful, high-status persons are better able to abuse children, because they have a superior capacity to obtain the acquiescence and overcome the resistance of children to their abusive advances, evade detection of their abusive behavior, and escape accountability for their detected abuse.

Objective: We conduct quantitative empirical analyses designed to confirm the presumption that powerful, high-status persons are better able to abuse children in YSOs.

Setting: We analyzed 85 episodes of CSA linked to Boys and Girls Clubs (BGCs) affiliated with the Boys and Girls Clubs of America, identified by a Hearst Connecticut reporting team.

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Article Synopsis
  • Globally, while people are living longer, many experience a decline in health due to age-related diseases, highlighting the need for better classification systems to address these issues.
  • A consensus meeting with 150 experts established criteria for identifying ageing-related pathologies, requiring a 70% agreement for approval among participants.
  • The agreed criteria focus on conditions that progress with age, contribute to functional decline, and are backed by human studies, setting a foundation for future classification and staging efforts.
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Background: Child sexual abuse (CSA) remains an ongoing threat to the wellbeing of children who might be victimized, to the liberty of individuals who might engage in abusive behavior, and to the reputations and livelihood of organizations in which abuse might occur. In the U.S.

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The relationship between patterns of early growth and age-associated diseases such as type 2 diabetes and cardiovascular disease is well established. There is also strong evidence from both human and animal studies that early environmental factors such as maternal nutrition may influence lifespan. Interestingly, more recent studies have demonstrated that nutritional programming in early life effects immunity, such that altered lifespan can also lead to programmed changes in immune function.

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Interleukin-7 (IL-7) and its receptor (IL-7R) are essential for T cell development in the thymus, and changes in the IL-7/IL-7R pathway have been implicated in age-associated thymic involution which results in a reduction of naïve T cell output. The aim of this study was to investigate the relationship between IL7 and IL7R genetic variation and thymic output in dogs. No single nucleotide polymorphisms (SNPs) were identified in the canine IL7 gene, but a number were present in the canine IL7R gene.

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Immunosenescence is the gradual deterioration in immune system function associated with ageing. This decline is partly due to involution of the thymus, which leads to a reduction in the output of naive T cells into the circulating lymphocyte pool. Expansion of existing naive and memory T cell populations, to compensate for the reduction in thymic output, can lead to reduced diversity in the T cell repertoire with increasing age, resulting in impairment of immune responses to novel antigenic challenges, such as during infection and vaccination.

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This article draws on a report prepared for the Australian Royal Commission into Institutional Responses to Child Sexual Abuse (Palmer et al., 2016) to develop a more comprehensive analysis of the role that organizational culture plays in child sexual abuse in institutional contexts, where institutional contexts are taken to be formal organizations that include children among their members (referred to here as "youth-serving organizations"). We begin by integrating five strains of theory and research on organizational culture from organizational sociology and management theory into a unified framework for analysis.

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The age associated decline in immune function is preceded in mammals by a reduction in thymic output. Furthermore, there is increasing evidence of a link between immune competence and lifespan. One approach to determining thymic output is to quantify signal joint T cell receptor excision circles (sj-TRECs), a method which has been developed and used in several mammalian species.

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Environmental factors such as nutrition during early life can influence long-term health, a concept termed developmental programming. Initial research was focused towards the effects on metabolic health but more recent studies have demonstrated effects on parameters such as lifespan and immunity. In this study we report that maternal protein restriction during lactation in mice, that is known to prolong lifespan, slows aging of the central and peripheral immune systems.

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The precise mechanisms responsible for immunosenescence still remain to be determined, however, considering the evidence that disruption of the organization of primary and secondary lymphoid organs results in immunodeficiency, we propose that this could be involved in the decline of immune responses with age. Therefore, we investigated the integrity of the splenic microarchitecture in mice of increasing age and its reorganization following immune challenge in young and old mice. Several differences in the anatomy of the spleen with age in both the immune and stromal cells were observed.

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The thymic natural regulatory T cell (Treg) compartment of NOD mice is unusual in having reduced TCR diversity despite normal cellularity. In this study, we show that this phenotype is attributable to perturbations in early and late stages of thymocyte development and is controlled, at least in part, by the NOD Idd9 region on chromosome 4. Progression from double negative 1 to double negative 2 stage thymocytes in NOD mice is inefficient; however, this defect is compensated by increased proliferation of natural Tregs (nTregs) within the single positive CD4 thymocyte compartment, accounting for recovery of cellularity accompanied by loss of TCR diversity.

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Age-related regression of the thymus is associated with a decline in naïve T cell output. This is thought to contribute to the reduction in T cell diversity seen in older individuals and linked with increased susceptibility to infection, autoimmune disease, and cancer. Thymic involution is one of the most dramatic and ubiquitous changes seen in the aging immune system, but the mechanisms which underlying this process are poorly understood.

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The major function of the immune system is to provide protection against pathogens, in order to prevent infections and potential death. However, with increasing age the immune system undergoes alterations culminating in a progressive deterioration in the ability to respond to infection and vaccination. The precise mechanisms associated with immunosenescence have not been fully elucidated although extensive analyses have suggested that intrinsic defects within immune cells are potentially involved.

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Objective: Chronological age is a powerful epidemiologic risk factor for osteoarthritis (OA), a multifactorial disease that is characterized by articular cartilage (AC) degradation. It is unclear from a molecular perspective how aging interacts with OA to produce this risk to AC integrity. To address this key question, we used in vivo time-course analysis of OA development and murine interstrain variability in natural susceptibility to OA to examine changes in non-OA-prone CBA mice versus OA-prone STR/Ort mice, which develop disease that bears significant histologic resemblance to human OA.

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Age-related regression of the thymus is associated with a decline in naïve T cell output which is thought to contribute to the reduction in T cell diversity in older individuals that is partially responsible for an increase in susceptibility and severity of infections, cancers and autoimmune diseases. Thymic involution is one of the most dramatic and ubiquitous changes in the ageing immune system, but the precise regulators remain anonymous. However, a picture is emerging, implicating extrinsic and intrinsic factors that may contribute towards age-associated thymic involution.

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The function of lymphoid organs and immune cells is often modulated by hormones, steroids and neuropeptides produced by the neuroendocrine and immune systems. The thymus intrinsically produces these factors and a comparative analysis of the expression of neuropeptides in the thymus of different species would highlight the evolutionary importance of neuroendocrine interaction in T cell development. In this review, we highlight the evidence which describes the intrathymic expression and function of various neuropeptides and their receptors, in particular somatostatin, substance P, vasointestinal polypeptide, calcitonin gene-related peptide and neuropeptide Y, in mammals (human, rodent) and non-mammals (avian, amphibian and teleost), and conclude that neuropeptides play a conserved role in vertebrate thymocyte development.

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Regression of the thymus is a key feature of immunosenescence, which coincides with a decrease in T cell output and contributes to the restriction of the T cell repertoire in the elderly, leading to increased susceptibility to illness and disease. However, the mechanisms involved in thymic involution are still not fully known. Although, it is often believed that thymic involution occurs during the onset of puberty, increasing data suggests alterations to the thymus happen much earlier in life.

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Human natural killer (NK) cells subsets are phenotypically characterized by their lack of CD3 and low/high expression of CD56. This study revealed an age-associated increase in the ratio of CD3(-)CD56(dim) to CD3(-)CD56(bright) NK cells, whereas distinct expression patterns of CD2, CD16, CD57, and the C-type lectin family members killer cell lectin-like receptor -D1 (CD94) and -G1 (KLRG1), were noted on both these NK and the CD3(+)CD56(+) T cell subsets; moreover, CD94 and KLRG1 expression were significantly reduced with age. Although the proportion of CD3(-)CD56(bright) NK cells vs CD3(-)CD56(dim) cells decreased with age, the percentage of CD3(-)CD56(bright) cells expressing IFN-gamma after activation significantly increased, potentially representing compensatory augmentation of cytokine production to maintain the important immunoregulatory role of these cells in older individuals.

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Butyrophilin (BTN) genes encode a set of related proteins. Studies in mice have shown that one of these, BTN1A1, is required for milk lipid secretion in lactation, whereas butyrophilin-like 2 is a coinhibitor of T cell activation. To understand these disparate roles of BTNs, we first compared the expression and functions of mouse Btn1a1 and Btn2a2.

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T cells are an integral part of a functional immune system with the majority being produced in the thymus. Of all the changes related to immunosenescence, regression of the thymus is considered one of the most universally recognised alterations. Despite the reduction of thymic size, there is evidence to suggest that T cell output is still present into old age, albeit much diminished; leading to the assumption that thymocyte development is normal.

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Nutrition and growth rate during early life can influence later health and lifespan. We have demonstrated previously that low birthweight, resulting from maternal protein restriction during pregnancy followed by catch-up growth in rodents, was associated with shortened lifespan, whereas protein restriction and slow growth during lactation increased lifespan. The underlying mechanisms by which these differences arise are unknown.

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There is an accumulating body of evidence that a decline in immune function with age is common to most if not all vertebrates. For instance, age-associated thymic involution seems to occur in all species that possess a thymus, indicating that this process is evolutionary ancient and conserved. The precise mechanisms regulating immunosenescence remain to be resolved, but much of what we do know is consistent with modern evolutionary theory.

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T-cell development is characterised by a complex series of events in the thymus, which results in the development of self-restricted immunocompetent lymphocytes. We have previously reported the expression of neuropeptides in the thymus of various species, highlighting the evolutionary importance of neuroendocrine interactions in thymocyte development. Despite the many physiological and functional similarities in their immune systems, no study has addressed the importance of neuropeptides and thymic hormones in T-cell development in Xenopus.

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The thymus is crucial for T-cell output and the age-associated involution of this organ, is thought to have a major impact in the decline in immunity that is seen in later life. The mechanism that underlines thymic involution is not known, however, we have evidence to suggest that this is may be due to changes in the thymic microenvironment. To further test this hypothesis, we quantified the in situ changes to markers that identify cortical and medullary thymic epithelial cells.

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Age-associated thymic involution is one of the most dramatic and ubiquitous changes in the immune system, although the precise mechanisms involved still remain obscured. Several hypotheses have been proposed incorporating extrinsic and intrinsic factors, however, changes in the thymic microenvironment itself is one of the least investigated. We therefore decided to undertake a detailed histological examination of the aging thymus in order to elucidate possible mechanisms of thymic atrophy.

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