Nutritional supplementation in Down syndrome: theoretical considerations and current status

Blood tests and use of nutritional supplements in a cohort of Brazilian children with trisomy 21

OBJECTIVE

To describe the use of nutritional supplements and blood status (hemogram, lipidogram, hepatic function, inflammatory markers, minerals, and homocysteine) in a sample of Brazilian T21 children with private health support before their first consultation with a T21 expert.

METHOD

This descriptive cross-sectional study enrolled 102 participants. Brazilian families with a T21 member under 18 years old were contacted and those that consented answered a survey regarding socio-demographics and the use of nutritional supplements and shared the blood tests that their T21 members have collected for the first consultation with a T21 expert.

RESULTS

Frequencies and percentages were used to describe the variables. The most used supplements included vitamins (A, C and D), minerals (zinc and iron), omega-3, and antioxidants (curcumin). Hypothyroidism was observed in 56.9% of the participants. Hemogram alterations (increased hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and red cell distribution width, leukopenia, and lymphocytopenia), dyslipidemia, altered hepatic and inflammatory blood markers were frequently found.

CONCLUSIONS

Nutritional supplements (mainly vitamins, minerals, omega-3 and antioxidants) are frequently used by Brazilian T21 children independently of professional counseling and/or supervision and should be a question to be raised during the clinical anamnesis since some of them may impact medical conduct. Moreover, many blood tests are altered in this population and clinicians should be aware of them in order to warrant an appropriate screening and the implementation of risk management measures as soon as possible and improve the general health of these persons.

Use of antioxidants supplementation on developmental outcomes in children with Down syndrome-A systematic review and meta-analyses

BACKGROUND

The background of this study is to evaluate the published literature on the use of antioxidants in improving developmental outcomes in children with DS.

METHODS

The systematic review included interventional studies (randomized controlled trials [RCTs] and quasi-RCTs [q-RCTs]) of children aged 0 to 18 years diagnosed with DS who received antioxidants to improve developmental outcomes. Studies were excluded if they were interventional studies with non-random allocation or lack of control group or non-interventional studies including observational studies, systematic and narrative review articles, editorials and commentaries. Studies were also excluded if data from participants with DS were included as part of a larger group of participants (e.g., children with intellectual disability) and the data could not be separated for subgroup analysis, or if outcomes did not assess developmental domains (e.g., reported biochemical markers only). The review included children with other conditions associated with developmental disability, only when data for children with DS were separately reported.

RESULTS

Eleven RCTs and q-RCTs fulfilled the eligibility criteria with 683 participants with Down syndrome ranging in age from newborns to 17 years. Nine studies did not show any statistically significant clinical benefit of using antioxidants. Three studies were included in a meta-analysis comparing changes in the effect sizes (post and pre-intervention) in Global Developmental Quotient (GDQ) between the intervention and control groups.

CONCLUSION

This review concludes that it is likely that the results are valid and suggest that the use of Antioxidant has no improvement in GDQ for children with DS. It is also unclear if any benefit exists for other developmental domains.

Antioxidants in Down Syndrome: From Preclinical Studies to Clinical Trials

There is currently no effective pharmacological therapy to improve the cognitive dysfunction of individuals with Down syndrome (DS). Due to the overexpression of several chromosome 21 genes, cellular and systemic oxidative stress (OS) is one of the most important neuropathological processes that contributes to the cognitive deficits and multiple neuronal alterations in DS. In this condition, OS is an early event that negatively affects brain development, which is also aggravated in later life stages, contributing to neurodegeneration, accelerated aging, and the development of Alzheimer's disease neuropathology. Thus, therapeutic interventions that reduce OS have been proposed as a promising strategy to avoid neurodegeneration and to improve cognition in DS patients. Several antioxidant molecules have been proven to be effective in preclinical studies; however, clinical trials have failed to show evidence of the efficacy of different antioxidants to improve cognitive deficits in individuals with DS. In this review we summarize preclinical studies of cell cultures and mouse models, as well as clinical studies in which the effect of therapies which reduce oxidative stress and mitochondrial alterations on the cognitive dysfunction associated with DS have been assessed.

A Search for Similar Patterns in Hair Trace Element and Mineral Content in Children with Down's Syndrome, Obesity, and Growth Delay

The objective of the present study was to perform comparative analysis of hair trace element and mineral levels in children with Down's syndrome, growth delay, and obesity in order to reveal common and specific patterns. Hair Zn (14, 7, and 15%), Ca (38%, 24%, and 47%), and Mg (33%, 31%, and 49%) levels in children with Down's syndrome, obesity, and growth delay were lower than the respective control values. At the same time, patients with Down's syndrome and growth delay were characterized by 27% and 21%, as well as 24% and 20% lower hair Co as well as Cu content than healthy examinees. Certain alterations were found to be disease-specific. Particularly, in Down's syndrome children, hair Cr, Fe, and V levels were significantly lower, whereas hair P content exceeded the control values. Obese children were characterized by significantly increased hair Cr content. At the same time, hair Mn and Si levels in children with growth delay were lower as compared with the controls. In regression models, all three studied diseases were considered as negative predictors of hair Cu content. Down's syndrome and growth delay, but not obesity, were inversely associated with hair Co content. Both Down's syndrome and obesity were inversely associated with hair Zn content. Based on the revealed similarities in altered hair element, content it is proposed that deficiency of essential elements may predispose Down's syndrome patients to certain syndrome comorbidities including growth delay and obesity, although further detailed studies are required.

Translational validity and implications of pharmacotherapies in preclinical models of Down syndrome

Neurodevelopmental disorders are challenging to study in the laboratory, and despite a large investment, few novel treatments have been developed in the last decade. While animal models have been valuable in elucidating disease mechanisms and in providing insights into the function of specific genes, the predictive validity of preclinical models to test potential therapies has been questioned. In the last two decades, diverse new murine models of Down syndrome (DS) have been developed and numerous studies have demonstrated neurobiological alterations that could be responsible for the cognitive and behavioral phenotypes found in this syndrome. In many cases, similar alterations were found in murine models and in individuals with DS, although several phenotypes shown in animals have yet not been confirmed in the human condition. Some of the neurobiological alterations observed in mice have been proposed to account for their changes in cognition and behavior, and have received special attention because of being putative therapeutic targets. Those include increased oxidative stress, altered neurogenesis, overexpression of the Dyrk1A gene, GABA-mediated overinhibition and Alzheimer's disease-related neurodegeneration. Subsequently, different laboratories have tested the efficacy of pharmacotherapies targeting these alterations. Unfortunately, animal models are limited in their ability to mimic the extremely complex process of human neurodevelopment and neuropathology. Therefore, the safety and efficacy identified in animal studies are not always translated to humans, and most of the drugs tested have not demonstrated any positive effect or very limited efficacy in clinical trials. Despite their limitations, though, animal trials give us extremely valuable information for developing and testing drugs for human use that cannot be obtained from molecular or cellular experiments alone. This chapter reviews some of these therapeutic approaches and discusses some reasons that could account for the discrepancy between the findings in mouse models of DS and in humans, including: (i) the incomplete resemble of the genetic alterations of available mouse models of DS and human trisomy 21, (ii) the lack of evidence that some of the phenotypic alterations found in mice (e.g., GABA-mediated overinhibition, and alterations in adult neurogenesis) are also present in DS individuals, and (iii) the inaccuracy and/or inadequacy of the methods used in clinical trials to detect changes in the cognitive and behavioral functions of people with DS. Despite the shortcomings of animal models, animal experimentation remains an invaluable tool in developing drugs. Thus, we will also discuss how to increase predictive validity of mouse models.

Glucagon-Like Peptide-1 Cleavage Product Improves Cognitive Function in a Mouse Model of Down Syndrome

Currently there is no effective therapy available for cognitive impairments in Down syndrome (DS), one of the most prevalent forms of intellectual disability in humans associated with the chromosomes 21 trisomy. Glucagon-like peptide-1 (GLP-1) is an incretin hormone that maintains glucose homeostasis by stimulating insulin secretion. Its natural cleavage product GLP-1 (9-36) lacks insulinotropic effects and has a low binding affinity for GLP-1 receptors; thus, GLP-1 (9-36) has historically been identified as an inactive metabolite. Conversely, recent work has demonstrated interesting physiological properties of GLP-1 (9-36) such as cardioprotection and neuroprotection. We have previously shown that GLP-1 (9-36) administration enhances neuronal plasticity in young WT mice and ameliorates cognitive deficits in a mouse model of Alzheimer's disease. Here, we report that systemic administration of GLP-1 (9-36) in Ts65Dn DS model mice of either sex resulted in decreased mitochondrial oxidative stress in hippocampus and improved dendritic spine morphology, increase of mature spines and reduction of immature spines. Importantly, these molecular alterations translated into functional changes in that long-term potentiation failure and cognitive impairments in TsDn65 DS model mice were rescued with GLP-1 (9-36) treatment. We also show that chronic GLP-1 (9-36) treatment did not alter glucose tolerance in either WT or DS model mice. Our findings suggest that GLP-1 (9-36) treatment may have therapeutic potential for DS and other neurodegenerative diseases associated with increased neuronal oxidative stress.

Cognitive Functioning in Children with Down Syndrome: Current Knowledge and Future Directions

Infants and children with Down syndrome (DS) can look forward toward bright futures, as individuals with DS are living healthier, more productive lives than ever due to medical advances, opportunities for early and continued intervention, and inclusive education. Despite these advances, infants and children with DS experience challenges in specific domains of cognitive functioning relative to their typically developing (TD) peers. Over the long term, individuals with DS are also more likely to develop Alzheimer's disease relative to the general population. Understanding cognitive functioning early in life may be important in charting cognitive decline over time. This chapter synthesizes the literature on cognitive functioning in infants and children with DS specific to general intelligence or IQ, language development, recall memory, and executive functioning, with additional focus on critical issues and future directions. These research findings provide important information for understanding cognitive competencies and intervention opportunities for children with DS and also serves to provide a foundation from which to plan longitudinal studies examining stability and change in cognitive functioning over time.

Pre- and post-natal melatonin administration partially regulates brain oxidative stress but does not improve cognitive or histological alterations in the Ts65Dn mouse model of Down syndrome

Melatonin administered during adulthood induces beneficial effects on cognition and neuroprotection in the Ts65Dn (TS) mouse model of Down syndrome. Here, we investigated the effects of pre- and post-natal melatonin treatment on behavioral and cognitive abnormalities and on several neuromorphological alterations (hypocellularity, neurogenesis impairment and increased oxidative stress) that appear during the early developmental stages in TS mice. Pregnant TS females were orally treated with melatonin or vehicle from the time of conception until the weaning of the offspring, and the pups continued to receive the treatment from weaning until the age of 5 months. Melatonin administered during the pre- and post-natal periods did not improve the cognitive impairment of TS mice as measured by the Morris Water maze or fear conditioning tests. Histological alterations, such as decreased proliferation (Ki67+ cells) and hippocampal hypocellularity (DAPI+ cells), which are typical in TS mice, were not prevented by melatonin. However, melatonin partially regulated brain oxidative stress by modulating the activity of the primary antioxidant enzymes (superoxide dismutase in the cortex and catalase in the cortex and hippocampus) and slightly decreasing the levels of lipid peroxidation in the hippocampus of TS mice. These results show the inability of melatonin to prevent cognitive impairment in TS mice when it is administered at pre- and post-natal stages. Additionally, our findings suggest that to induce pro-cognitive effects in TS mice during the early stages of development, in addition to attenuating oxidative stress, therapies should aim to improve other altered processes, such as hippocampal neurogenesis and/or hypocellularity.

Systemic oxidative stress in children and teenagers with Down syndrome

AIMS

The aim of this study was to evaluate the antioxidant status and oxidative stress biomarkers in the blood of children and teenagers with Down syndrome.

MAIN METHODS

The analysis of enzymatic antioxidant defenses, such as the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione transferase (GST), non-enzymatic antioxidants, such as levels of reduced glutathione (GSH), uric acid (UA) and vitamin E, as well as oxidative damage indicators, such as protein carbonyls (PC) levels and lipoperoxidation (TBARS), of DS individuals (n=20) compared to healthy controls (n=18). Except the vitamin E was measured by HPLC, all other markers were measured spectrophotometrically.

KEY FINDINGS

Antioxidant enzymes analysis showed significant increases in the SOD (47.2%), CAT (24.7%) and GR (49.6%) activities in DS subjects. No significant difference in GPx activity was detected while GST activity (61.2%) was decreased, and both responses may be consequence of the depletion of GSH (24.9%) levels. There were no significant differences in TBARS levels, while PC levels showed decreased (31.7%) levels compared to healthy controls, which may be related to the increase (16.1%) found in serum UA. Levels of vitamin E showed no significant differences between DS individuals compared to controls.

SIGNIFICANCE

The results revealed a systemic pro-oxidant status in DS individuals, evidenced by the increased activity of some important antioxidant enzymes, together with decreased GSH levels in whole blood and elevated UA levels in plasma, probably as an antioxidant compensation related to the redox imbalance in DS individuals.

Systemic oxidative stress, as measured by urinary allantoin and F(2)-isoprostanes, is not increased in Down syndrome

PURPOSE

Oxidative stress has been implicated in Down syndrome (DS) pathology. This study compares DS individuals and controls on their urinary levels of allantoin and 2,3-dinor-iPF2α-III; these biomarkers have been previously validated in a clinical model of oxidative stress.

METHODS

Urine samples were collected from 48 individuals with DS and 130 controls. Biomarkers were assayed by ultraperformance liquid chromatography-tandem mass spectrometry, normalized by urinary creatinine concentration.

RESULTS

After adjusting for age and gender, mean allantoin levels were lower among DS individuals versus controls (P = .04). The adjusted mean levels of 2,3-dinor-iPF2α-III were similar in DS individuals and controls (P = .7).

CONCLUSIONS

Our results do not support the hypothesis that DS individuals have chronic systemic oxidative stress.

α-Tocopherol suppresses lipid peroxidation and behavioral and cognitive impairments in the Ts65Dn mouse model of Down syndrome

It is widely accepted that oxidative stress is involved in the pathogenesis of Down syndrome, but the effectiveness of antioxidant treatment remains inconclusive. We tested whether chronic administration of α-tocopherol ameliorates the cognitive deficits exhibited by Ts65Dn mice, a mouse model of Down syndrome. α-Tocopherol was administered to pregnant Ts65Dn females, from the day of conception throughout the pregnancy, and to pups over their entire lifetime, from birth to the end of the behavioral testing period. Cognitive deficits were confirmed for Ts65Dn mice fed a control diet, revealing reduced anxiety or regardlessness in the elevated-plus maze task test and spatial learning deficits in the Morris water maze test. However, supplementation with α-tocopherol attenuated both cognitive impairments. In addition, we found that levels of 8-iso-prostaglandin F(2α) in brain tissue and hydroxyoctadecadienoic acid and 7-hydroxycholesterol in the plasma of Ts65Dn mice were higher than those of control mice. Supplementation with α-tocopherol decreased levels of lipid peroxidation products in Ts65Dn mice. Furthermore, we found out that α-tocopherol improved hypocellularity in the hippocampal dentate gyrus of Ts65Dn mice. These results imply that α-tocopherol supplementation from an early stage may be an effective treatment for the cognitive deficits associated with Down syndrome.

[Vitamin A deficiency and nutritional status in patients with Down's syndrome]

INTRODUCTION

Vitamin A deficiency (VAD) is a worldwide public health problem. Epidemiological studies of VAD prevalence have been conducted in individuals with chromosome load and genetic potential compared with the general population; however, there are few studies in patients with Down's syndrome (DS). The objective of this study was to determine the prevalence of VAD and analyse nutritional status in patients with DS.

METHODS

A prospective and cross-sectional study was performed, with 50 karyotypically normal (KN) individuals (10.4+/-3.7 years old) and 38 randomly selected patients with DS (8.2+/-4.1 years old). Serum retinol was determined by HPLC using the Bieri method, with an international reference standard to define VAD (serum retinol <20 microg/dL). The data were analysed using the SAS/STAT statistical program.

RESULTS

The prevalence of VAD was 18.4% in individuals with DS and 4% in KN individuals (OR: 5.42; 95% CI=0.93-40.64; p=0.02). Children with DS between two and six years old shown a significativily lower serum retinol (p=<0.05).The patients with DS also showed a significant decrease in height and weight compared to KN (p=<0.001).

CONCLUSIONS

The prevalence of VAD detected in patients with DS could be considered a public health problem. Also, the chromosome 21 trisomy represent a risk factor associated with VAD.

The 50th anniversary of the discovery of trisomy 21: the past, present, and future of research and treatment of Down syndrome

Trisomy 21 or Down syndrome is a chromosomal disorder resulting from the presence of all or part of an extra Chromosome 21. It is a common birth defect, the most frequent and most recognizable form of mental retardation, appearing in about 1 of every 700 newborns. Although the syndrome had been described thousands of years before, it was named after John Langdon Down who reported its clinical description in 1866. The suspected association of Down syndrome with a chromosomal abnormality was confirmed by Lejeune et al. in 1959. Fifty years after the discovery of the origin of Down syndrome, the term "mongolism" is still inappropriately used; persons with Down syndrome are still institutionalized. Health problems associated with that syndrome often receive no or little medical care, and many patients still die prematurely in infancy or early adulthood. Nevertheless, working against this negative reality, community-based associations have lobbied for medical care and research to support persons with Down syndrome. Different Trisomy 21 research groups have already identified candidate genes that are potentially involved in the formation of specific Down syndrome features. These advances in turn may help to develop targeted medical treatments for persons with Trisomy 21. A review on those achievements is discussed.

Vitamin supplement use among children with Down's syndrome and risk of leukaemia: a Children's Oncology Group (COG) study

Vitamin supplements have been proposed for children with Down's syndrome (DS) with claims of improving cognitive abilities, or immune or thyroid function. Several studies have shown decreased levels of zinc in this population. Because children with DS have a 50-fold increased risk of developing acute leukaemia during the first 5 years of life, we explored the relation between child vitamin and herbal supplement use and the risk of leukaemia in a case-control study. During the period 1997-2002, we enrolled 158 children with DS aged 0-18 years that were diagnosed with acute lymphoblastic leukaemia (ALL) (n = 97) or acute myeloid leukaemia (AML) (n = 61) at participating Children's Oncology Group institutions. We enrolled 173 DS children without leukaemia (controls), selected from the cases' primary care clinic and frequency-matched on age. Data were collected via telephone interviews with mothers of the index child regarding use of multivitamins, zinc, vitamin C, iron and herbal supplements, including age at first use, frequency and duration. Among controls, 57% reported regular multivitamin use (>/=3 times/week for >/=3 months) compared with 48% of ALL cases and 61% of AML cases. We found no evidence of an association between children's regular multivitamin use and ALL or AML (adjusted odds ratios [OR] = 0.94 [95% CI 0.52, 1.70] and 1.90 [0.73, 4.91] respectively). There was a suggestion of an increased risk for AML associated with regular multivitamin use during the first year of life or for an extended duration (ORs = 2.38 [0.94, 5.76] and 2.59 [1.02, 6.59] respectively). Despite being the largest study of DS-leukaemia, our sample size was small, resulting in imprecise effect estimates. Future research should include larger sample sizes as well as a full assessment of diet including vitamin supplementation to adequately examine the relation between nutritional status and childhood leukaemia.

Supplementation with antioxidants and folinic acid for children with Down's syndrome: randomised controlled trial

OBJECTIVES

To assess whether supplementation with antioxidants, folinic acid, or both improves the psychomotor and language development of children with Down's syndrome.

DESIGN

Randomised controlled trial with two by two factorial design.

SETTING

Children living in the Midlands, Greater London, and the south west of England.

PARTICIPANTS

156 infants aged under 7 months with trisomy 21.

INTERVENTION

Daily oral supplementation with antioxidants (selenium 10 mug, zinc 5 mg, vitamin A 0.9 mg, vitamin E 100 mg, and vitamin C 50 mg), folinic acid (0.1 mg), antioxidants and folinic acid combined, or placebo.

MAIN OUTCOME MEASURES

Griffiths developmental quotient and an adapted MacArthur communicative development inventory 18 months after starting supplementation; biochemical markers in blood and urine at age 12 months.

RESULTS

Children randomised to antioxidant supplements attained similar developmental outcomes to those without antioxidants (mean Griffiths developmental quotient 57.3 v 56.1; adjusted mean difference 1.2 points, 95% confidence interval -2.2 to 4.6). Comparison of children randomised to folinic acid supplements or no folinic acid also showed no significant differences in Griffiths developmental quotient (mean 57.6 v 55.9; adjusted mean difference 1.7, -1.7 to 5.1). No between group differences were seen in the mean numbers of words said or signed: for antioxidants versus none the ratio of means was 0.85 (95% confidence interval 0.6 to 1.2), and for folinic acid versus none it was 1.24 (0.87 to 1.77). No significant differences were found between any of the groups in the biochemical outcomes measured. Adjustment for potential confounders did not appreciably change the results.

CONCLUSIONS

This study provides no evidence to support the use of antioxidant or folinic acid supplements in children with Down's syndrome.

TRIAL REGISTRATION

Clinical trials NCT00378456.

Oxidative stress: A bridge between Down's syndrome and Alzheimer's disease

Besides the genetic, biochemical and neuropathological analogies between Down's syndrome (DS) and Alzheimer's disease (AD), there is ample evidence of the involvement of oxidative stress (OS) in the pathogenesis of both disorders. The present paper reviews the publications on DS and AD in the past 10 years in light of the "gene dosage" and "two-hit" hypotheses, with regard to the alterations caused by OS in both the central nervous system and the periphery, and the main pipeline of antioxidant therapeutic strategies. OS occurs decades prior to the signature pathology and manifests as lipid, protein and DNA oxidation, and mitochondrial abnormalities. In clinical settings, the assessment of OS has traditionally been hampered by the use of assays that suffer from inherent problems related to specificity and/or sensitivity, which explains some of the conflicting results presented in this work. For DS, no scientifically proven diet or drug is yet available, and AD trials have not provided a satisfactory approach for the prevention of and therapy against OS, although most of them still need evidence-based confirmation. In the future, a balanced up-regulation of endogenous antioxidants, together with multiple exogenous antioxidant supplementation, may be expected to be one of the most promising treatment methods.

Complementary and alternative therapies for Down syndrome

In their role as committed advocates, parents of children with Down syndrome have always sought alternative therapies, mainly to enhance cognitive function but also to improve their appearance. Nutritional supplements have been the most frequent type of complementary and alternative therapy used. Cell therapy, plastic surgery, hormonal therapy, and a host of other therapies such as massage therapy have been used. There is a lack of well-designed scientific studies on the use of alternative therapies in individuals with Down syndrome. Antioxidants hold theoretical promise for treatment of the cognitive, immune, malignancy, and premature aging problems associated with Down syndrome. Medications for treatment of Alzheimer's disease may also result in benefit for the population of individuals with Down syndrome.

Between ‘desperation’ and disability rights: a narrative analysis of complementary/alternative medicine use by parents for children with Down syndrome

This paper presents a narrative analysis of complementary/alternative medicine (CAM) use by parents for children with Down syndrome (DS), based on interviews conducted with thirty families. Critics often presume that CAM use for children with developmental disabilities reflects parental desperation in the face of limited biomedical options. Integrating insights from anthropological studies of CAM with narrative analyses in disability studies, we constructively complicate this interpretation in two ways. First, we suggest that the appeal of CAM may lie in its discursive consonance with the broader narrative strategies through which parents construct alternatives to conventional definitions of DS as a condition with a fixed, universal, and essentially pathological course. Second, we submit that the process of seeking and evaluating information about CAM is consonant with how parents construct their identities as 'good' parents through describing their roles as committed advocates and service coordinators for their children. In these ways, CAM can be conceptualized as a new discursive resource that parents engage in their culturally and historically specific efforts to articulate the essential human rights of their children, and to assert the moral soundness of their own parenthood. These findings provide a new conceptualization of parents' motives for choosing CAM, thereby posing new questions for further research about CAM use for developmental disabilities.

Communicating with pediatricians about complementary/alternative medicine: perspectives from parents of children with down syndrome

OBJECTIVES

Barriers to communication about complementary/alternative medicine (CAM) between parents and pediatricians are frequently documented, yet the scope of these barriers remains poorly understood. Such barriers are especially troubling when they involve children with special health needs, among whom CAM use is especially common. This pilot study of parents of children with Down syndrome (DS) used qualitative methods to explore parents' perceptions of the extent and quality of communication about CAM with pediatricians, to elicit parents' recommendations for improvement, and to formulate new research questions.

DESIGN

Semistructured interviews were conducted with parents from 30 families with children with DS. Data were audiotaped and analyzed with assistance from qualitative data analysis software.

RESULTS

Parents described how they advocated vigorously with their pediatricians about biomedical concerns such as the American Academy of Pediatrics healthcare guidelines for DS, but often avoided discussion of nonbiomedical concerns such as CAM. Many parents looked to pediatricians to initiate conversations about CAM.

DISCUSSION

Even parents who assertively advocate for biomedical concerns in their children's health care may be unlikely to disclose and discuss CAM use with their pediatricians. Attending to parents' experiences helps to illuminate the nature and scope of current communication barriers and poses new research questions for assessing and improving parent-physician collaboration about health-related issues that may be prioritized differently by parents and pediatricians.

Down's syndrome

The sequencing of chromosome 21 and the use of models of Down's syndrome in mice have allowed us to relate genes and sets of genes to the neuropathogenesis of this syndrome, and to better understand its phenotype. Research in prenatal screening and diagnosis aims to find methods to identify fetuses with Down's syndrome, and reduce or eliminate the need for amniocentesis. Other areas of active research and clinical interest include the association of Down's syndrome with coeliac disease and Alzheimer's disease, and improved median age of death. Medical management of the syndrome requires an organised approach of assessment, monitoring, prevention, and vigilance. Improvements in quality of life of individuals with Down's syndrome have resulted from improvements in medical care, identification and treatment of psychiatric disorders (such as depression, disruptive behaviour disorders, and autism), and early educational interventions with support in typical educational settings. Approaches and outcomes differ throughout the world.

Effect of overexpression of wild-type and mutant Cu/Zn-superoxide dismutases on oxidative damage and antioxidant defences: relevance to Down's syndrome and familial amyotrophic lateral sclerosis

Patients with Down's syndrome (DS) show elevated levels of copper, zinc-containing superoxide dismutase (SOD1) and appear to have increased lipid peroxidation and oxidative damage to DNA as well as elevated glutathione peroxidase activity. Increasing SOD1 levels by gene transfection in NT-2 and SK-N-MC cell lines also led to a rise in glutathione peroxidase activity, but this was nevertheless accompanied by decreased proliferation rates, increased lipid peroxidation and protein carbonyls, and a trend to a rise in 8-hydroxyguanine and protein-bound 3-nitrotyrosine. Transfection of these cell lines with DNA encoding two mutant SOD1 enzymes (G37R and G85R) associated with familial amyotrophic lateral sclerosis (FALS), produced similar, but more severe changes, i.e. even lower growth rates, higher lipid peroxidation, 3-nitrotyrosine and protein carbonyl levels, decreased GSH levels, raised GSSG levels and higher glutathione peroxidase activities. Since G85R has little SOD activity, these changes cannot be related to increased O(2)(-) scavenging. In no case was SOD2 (mitochondrial Mn-SOD) level altered. Our cellular systems reproduce many of the biochemical changes observed in patients with DS or ALS, and in transgenic mice overexpressing mutant SOD1. They also show the potentially deleterious effects of SOD1 overexpression on cellular proliferation, which may be relevant to abnormal development in DS.