Astrocytes: biology and pathology

Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS. Astrocytes respond to all forms of CNS insults through a process referred to as reactive astrogliosis, which has become a pathological hallmark of CNS structural lesions. Substantial progress has been made recently in determining functions and mechanisms of reactive astrogliosis and in identifying roles of astrocytes in CNS disorders and pathologies. A vast molecular arsenal at the disposal of reactive astrocytes is being defined. Transgenic mouse models are dissecting specific aspects of reactive astrocytosis and glial scar formation in vivo. Astrocyte involvement in specific clinicopathological entities is being defined. It is now clear that reactive astrogliosis is not a simple all-or-none phenomenon but is a finely gradated continuum of changes that occur in context-dependent manners regulated by specific signaling events. These changes range from reversible alterations in gene expression and cell hypertrophy with preservation of cellular domains and tissue structure, to long-lasting scar formation with rearrangement of tissue structure. Increasing evidence points towards the potential of reactive astrogliosis to play either primary or contributing roles in CNS disorders via loss of normal astrocyte functions or gain of abnormal effects. This article reviews (1) astrocyte functions in healthy CNS, (2) mechanisms and functions of reactive astrogliosis and glial scar formation, and (3) ways in which reactive astrocytes may cause or contribute to specific CNS disorders and lesions

Development of Functional Symptoms in Children Exposed to Traumatic Events

This chapter will review the typical symptoms occurring in children after stressful traumatic exposures. Unlike other chapters in this book, no specific organ system is the most likely focus of functional symptoms in this setting. Psychological distress may exacerbate symptoms of physical illness and injury associated with the traumatic events, may be expressed as almost any seemingly unrelated symptom, may intensify the age appropriate fears typical of any child, or may predominantly be exhibited behaviorally. In most nonsevere cases, the impact is self-limited and the individual’s functioning will be back to normal within days or weeks. We will suggest simple behavioral and environmental interventions intended to help relieve children’s distress. However, when large populations are affected and individuals suffer severe loss such as in a mass casualty disaster, the scale of events requires community-wide efforts to meet the needs of children and their families. The fact that some children are more psychosocially vulnerable than others will be discussed. The chapter will conclude by highlighting warning signs warranting professional mental health care

The downward spiral of mental disorders and educational attainment: a systematic review on early school leaving.

BACKGROUND: Most psychiatric disorders present symptom patterns that cause severe impairment on the emotional, cognitive and social level. Thus, adolescents who suffer from a mental disorder risk finding themselves in a downward spiral caused by the reciprocal association of psychological symptoms and negative school experiences that may culminate in early school leaving. In addition to previous collective work that mainly focused on school refusing behaviour among children and was presented as an expert's opinion, the following systematic review fills the knowledge gap by providing a structured overview of the bidirectional association between mental health and secondary school dropout based on a sound methodology and with a particular focus on mediating factors. METHODS: Four electronic databases were searched from January 1990 until June 2014. Selected references were assessed for study details, main results, mediating factors and methodological limitations. Standardized risk of bias assessment was conducted. RESULTS: Mood and anxiety disorders seemed to have a less consequential direct effect on early school leaving than substance use and disruptive behaviour disorders. The association between externalizing disorders and educational attainment was even stronger when the disorder occurred early in life. On the other hand, internalizing disorders were reported to develop as a consequence of school dropout. Only few studies had addressed gender differences, with discrepant results. Socio-economic background, academic achievement and family support were identified as significant mediating factors of the association between mental disorders and subsequent educational attainment. CONCLUSIONS: Findings suggested a strong association between mental health and education, in both directions. However, most studies focused on mediating factors that could not be targeted by intervention programs

Maternal and child predictors of low-income children's educational attainment

Much research has investigated maternal and child predictors of educational attainment. This longitudinal study builds on past research by examining how everyday mother-child conversations about decision-making in early adolescence predict adolescents' decisions to drop out of high school, terminate their education with a high school degree, or complete high school and enroll in tertiary education. Forty-four mothers' use of emotionally enabling speech and willingness to allow their 7th grade children (25 girls; 19 boys) to select their friends predicted children's later decisions about educational attainment in high school. In contrast, children's reported intrinsic motivation, receptive vocabulary scores, and mothers' education did not predict children's educational attainment. These findings underscore the importance of going beyond status variables such as maternal education, to incorporate measures of parent-child interaction in predicting adolescents' educational trajectories. © 2007 Elsevier Inc. All rights reserved