BACKGROUND: Down syndrome (DS) affects approximately 1 per 650-1000 live births and is the most common known genetic cause of intellectual disability. A highly significant change in the survival of people with DS has occurred during the last two generations, with life expectancy estimates increasing from 12 to nearly 60 years of age. SUBJECTS AND METHODS: Detailed information on 1332 people in Western Australia with DS was abstracted from a specialist statewide database for the period 1953-2000 and electronically linked with three other state or national health and mortality data sources and the state Birth Defects Registry. RESULTS: Over the last 25 years the percentage of women over 35 years giving birth increased from 4.8 to 18.6%, accompanied by an increase in the overall prevalence of DS from 1.1 to 2.9 per 1000 births. Four life stages of DS were identified: prenatal, childhood and early adulthood, adulthood, and senescence. Although pneumonia, or other types of respiratory infections, was the most common cause of death across the entire lifespan, ranging from 23% of deaths in adulthood to 40% in senescence, each life stage exhibited a particular profile of comorbidities. Congenital heart defects were common causes in childhood (13%) and adulthood (23%), whereas in senescence coronary artery disease (10%) and cardiac, renal, and respiratory failure (9%) were leading causes of mortality. CONCLUSIONS: A major re-appraisal in attitudes towards DS is required to ensure that the medical and social needs of people with the disorder are adequately met across their entire lifespan. In particular, specific recognition of the comorbidities that can arise at different ages is needed, accompanied by the provision of appropriate levels of care and management. (+info)
Standardized assessment of cognitive functioning during development and aging using an automated touchscreen battery.
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This study examined the effects of age, gender and education on subjects spanning nine decades on a new cognitive battery of 12 tests. One thousand and seven participants between 6 and 82 completed the battery under standardized conditions using an automated, computerized touchscreen. Sensitive indicators of change were obtained on measures of attention and working memory, learning and memory retrieval, and language, visuospatial function, sensori-motor and executive function. Improvement tended to occur through to the third and fourth decade of life, followed by gradual decrement and/or stabilized performance thereafter. Gender differences were obtained on measures of sustained attention, verbal learning and memory, visuospatial processing and dexterity. Years of education in adults was reflected in performance on measures of verbal function. Overall, the test battery provided sensitive indicators on a range of cognitive functions suitable for the assessment of abnormal cognition, the evaluation of treatment effects and for longitudinal case management. (+info)
Relationships of age at menarche and menopause, and reproductive year with mortality from cardiovascular disease in Japanese postmenopausal women: the JACC study.
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BACKGROUND: Early menopause is associated with increased risk of coronary heart disease in Caucasian women. However, this association has not been examined in Asian women. METHODS: We conducted a 10-year cohort study of 37,965 Japanese post-menopausal women aged 40-79 years in the Japan Collaborative Cohort (JACC) Study. Causes of death were determined based on the International Classification of Disease. RESULTS: There were 487 mortality of stroke and 178 mortality of coronary heart disease. Late menarche or early menopause, or shorter duration of reproductive period was not associated with risk of mortality from coronary heart disease. However, compared with women with age at menarche < or =13 years, those with age at menarche > or =17 years tended to have increased risk of mortality from stroke: the multivariable hazard ratio was 1.32 (95% confidence interval [CI]: 0.93-1.87, p = 0.10). Compared with women with age at menopause of > or =49 years, those with age at menopause of <49 years tended to have increased risk of coronary heart disease among women aged 40-64 years; the multivariable hazard ratio was 1.85 (95% CI: 0.92-3.73, p = 0.08). CONCLUSIONS: The possible association between early menopause and coronary heart disease among middle-aged women was consistent with the result of observational studies for Caucasian women, and can be explained by a protective effect of endogenous estrogen on the development of atherosclerosis. (+info)
Human development IV: the living cell has information-directed self-organisation.
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In this paper, restricted to describe the ontogenesis of the cell, we discuss the processing of DNA through RNA to proteins and argue that this process is not able to transfer the information necessary to organize the proteins in the cell, but only to transfer the information necessary to form the shape of the proteins. We shortly describe the structure of the information carrying field recruited by the cells that we think is responsible for building the organelles and other cellular structures. We use the cells superior control of its cytoskeleton as an example of how the cell is using an informational field giving the positional information guiding all the local chemical processes behind the cell movement. We describe the information-directed self-organization in cells and argue that this can explain the ontogenesis of the cell. We also suggest the existence of an undiscovered phenomenon behind the information transmitting cell interactions. We conclude that during evolution the cell has developed into an information-guided self-organizing structure. The mystery we want to solve is: what is the mechanical cause and nature of biological information? (+info)
The roles of cilia in developmental disorders and disease.
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Cilia are highly conserved organelles that have diverse motility and sensory functions. Recent discoveries have revealed that cilia also have crucial roles in cell signaling pathways and in maintaining cellular homeostasis. As such, defects in cilia formation or function have profound effects on the development of body pattern and the physiology of multiple organ systems. By categorizing syndromes that are due to cilia dysfunction in humans and from studies in vertebrate model organisms, molecular pathways that intersect with cilia formation and function have come to light. Here, we summarize an emerging view that in order to understand some complex developmental pathways and disease etiologies, one must consider the molecular functions performed by cilia. (+info)
The development of area discrimination and its implications for number representation in infancy.
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This paper investigates the ability of infants to attend to continuous stimulus variables and how this capacity relates to the representation of number. We examined the change in area needed by 6-month-old infants to detect a difference in the size of a single element (Elmo face). Infants successfully discriminated a 1:4, 1:3 and 1:2 change in the area of the Elmo face but failed to discriminate a 2:3 change. In addition, the novelty preference was linearly related to the ratio difference between the novel and familiar area. Results suggest that Weber's Law holds for area discriminations in infancy and also reveal that at 6 months of age infants are equally sensitive to number, time and area. (+info)
Human development V: biochemistry unable to explain the emergence of biological form (morphogenesis) and therefore a new principle as source of biological information is needed.
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Today's biomedicine builds on the conviction that biochemistry can explain the creation of the body, its anatomy and physiology. Unfortunately there are still deep mysteries strangely "fighting back" when we try to define and understand the organism and its creation in the ontogenesis as emerging from biochemistry. In analysing this from a theoretical perspective using a mathematical model focusing on the noise in complex chemical systems we argue that evolving biological structure cannot in principle be a product of chemistry. In this paper we go through the chemical gradient model and argue that this is not able to explain the ontogenesis. We discuss the used gradients as information carriers in chemical self-organizing systems and argue that by use of the "Turing structures" we are only able to modelling the mostly simple biological systems. The bio-chemical model is only able to model simple organization but not to explain the complexity of biological phenomena. We conclude that we seemingly have presented a formal proof (a NO-GO theorem) that the self-organizing chemical systems that are using chemical gradients are not able to explain complex biological matters as the ontogenesis. We need a fundamentally new, information-carrying principle to understand biological information and biological order. (+info)
Life-span development of visual working memory: when is feature binding difficult?
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We asked whether the ability to keep in working memory the binding between a visual object and its spatial location changes with development across the life span more than memory for item information. Paired arrays of colored squares were identical or differed in the color of one square, and in the latter case, the changed color was unique on that trial (item change) or was duplicated elsewhere in the array (color-location binding change). Children (8-10 and 11-12 years old) and older adults (65-85 years old) showed deficits relative to young adults. These were only partly simulated by dividing attention in young adults. The older adults had an additional deficiency, specifically in binding information, which was evident only when item- and binding-change trials were mixed together. In that situation, the older adults often overlooked the more subtle, binding-type changes. Some working memory processes related to binding undergo life-span development in an inverted-U shape, whereas other, bias- and salience-related processes that influence the use of binding information seem to develop monotonically. (+info)