Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Circulation ; 133(4): 398-408, 2016 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-26671979

RESUMO

BACKGROUND: Several distributions of country-specific blood pressure (BP) percentiles by sex, age, and height for children and adolescents have been established worldwide. However, there are no globally unified BP references for defining elevated BP in children and adolescents, which limits international comparisons of the prevalence of pediatric elevated BP. We aimed to establish international BP references for children and adolescents by using 7 nationally representative data sets (China, India, Iran, Korea, Poland, Tunisia, and the United States). METHODS AND RESULTS: Data on BP for 52 636 nonoverweight children and adolescents aged 6 to 19 years were obtained from 7 large nationally representative cross-sectional surveys in China, India, Iran, Korea, Poland, Tunisia, and the United States. BP values were obtained with certified mercury sphygmomanometers in all 7 countries by using standard procedures for BP measurement. Smoothed BP percentiles (50th, 90th, 95th, and 99th) by age and height were estimated by using the Generalized Additive Model for Location Scale and Shape model. BP values were similar between males and females until the age of 13 years and were higher in males than females thereafter. In comparison with the BP levels of the 90th and 95th percentiles of the US Fourth Report at median height, systolic BP of the corresponding percentiles of these international references was lower, whereas diastolic BP was similar. CONCLUSIONS: These international BP references will be a useful tool for international comparison of the prevalence of elevated BP in children and adolescents and may help to identify hypertensive youths in diverse populations.


Assuntos
Determinação da Pressão Arterial/normas , Pressão Sanguínea/fisiologia , Internacionalidade , Adolescente , Determinação da Pressão Arterial/métodos , Estatura/fisiologia , Peso Corporal/fisiologia , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Valores de Referência
2.
J Pediatr ; 164(6): 1358-62.e2, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24655536

RESUMO

OBJECTIVES: To develop reference percentile curves in Indian children for waist circumference (WC), and to provide a cutoff of WC percentile to identify children at risk for metabolic syndrome (MS). STUDY DESIGN: A multicenter, cross-sectional study was performed in 5 major Indian cities. Height, weight, and blood pressure (BP) were measured in 10,842 children (6065 boys). Elevated BP was defined as either systolic BP or diastolic BP >95th percentile. WC was measured with the child standing using a stretch-resistant tape. Sex-specific reference percentiles were computed using the LMS method which constructs reference percentiles adjusted for skewness. To determine optimal cutoffs for WC percentiles, a validation sample of 208 children was assessed for MS risk factors (ie, anthropometry, BP, blood lipids), and receiver operating characteristic (ROC) curve analysis was performed. RESULTS: Age- and sex-specific WC percentiles (5th, 10th, 15th, 25th, 50th, 75th, 85th, 90th, and 95th) are presented. WC values increased with age in both the boys and the girls. The median WC at age >15 years was greater in boys compared with girls. ROC analysis suggested the 70th percentile as a cutoff for MS risk (sensitivity, 0.84 in boys and 0.82 in girls; specificity, 0.85 in both boys and girls; area under the ROC curve, 0.88 in boys and 0.92 in girls). CONCLUSION: Age- and sex-specific reference curves for WC for Indian children and cutoff values of 70th WC percentile for screening for MS risk are provided.


Assuntos
Síndrome Metabólica/diagnóstico , Obesidade/diagnóstico , Circunferência da Cintura , Adolescente , Fatores Etários , Determinação da Pressão Arterial , Estatura , Índice de Massa Corporal , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Índia , Masculino , Síndrome Metabólica/prevenção & controle , Obesidade/prevenção & controle , Valor Preditivo dos Testes , Curva ROC , Padrões de Referência , Reprodutibilidade dos Testes , Medição de Risco , Fatores Sexuais
3.
J Diet Suppl ; 16(4): 390-400, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29958027

RESUMO

Hyperglycemia results in the overproduction of free oxygen radicals that impair the endogenous antioxidant defenses. A randomized controlled trial was conducted to compare the effect of 3 months of antioxidant supplementation in the form of foods rich in micronutrients with pharmacological supplement on total antioxidant status of Indian children with type 1 diabetes. Ninety children with diabetes (mean age 11.5 ± 3.6 yrs, 37 boys) were randomly allocated to three groups: Group 1 (n = 31) = DM controls; Group 2 (n = 30) = multimicronutrient syrup; and Group 3 (n = 29) = dietary supplements (nine snack recipes rich in micronutrients). They received intervention for 3 months. Healthy controls were enrolled from local schools. Fasting blood was tested for total antioxidant status (TAS) and glycosylated hemoglobin (HbA1C). Children with diabetes had lower TAS (0.70 ± 0.2 vs. 1 ± 0.24 mmol/l, p = .0001) compared to healthy controls. Anthropometric and biochemical parameters were similar at baseline for all groups of diabetic children. Group 1 showed significant deterioration in TAS at endline (0.72 ± 0.16 vs. 0.60 ± 0.17 mmol/l, p = .008). Increase in TAS recorded in Group 2 was from 0.66 ± 0.21 to 0.70 ± 0.16 mmol/l and in Group 3 was from 0.68 to 0.73 mmol/l. There was a significant difference between Group 1 and Group 3 for percentage change in TAS (-13% vs. 16%, p = .035). Postsupplementation there was an increase in TAS values in children with diabetes, but they were still lower than in healthy controls. Indian diabetic children have compromised antioxidant status, which may be improved by incorporation of multimicronutrient-rich recipes in their diets.


Assuntos
Antioxidantes/administração & dosagem , Antioxidantes/análise , Diabetes Mellitus Tipo 1/sangue , Adolescente , Glicemia/análise , Índice de Massa Corporal , Criança , Diabetes Mellitus Tipo 1/tratamento farmacológico , Dieta , Suplementos Nutricionais , Jejum , Feminino , Hemoglobinas Glicadas/análise , Humanos , Masculino , Micronutrientes/administração & dosagem
4.
Indian Pediatr ; 56(1): 23-28, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30806356

RESUMO

OBJECTIVE: To assess height velocity and develop height velocity percentiles in 5-17-year-old Indian children; and to study the magnitude and age at peak height velocity. DESIGN: Mixed longitudinal study. SETTING: Private schools at Pune and Delhi. PARTICIPANTS/PATIENTS: 2949 children (1681 boys) belonging to affluent class aged 5-17 years (1473-Pune, 1476-Delhi). METHODS: Annual height and weight measurements from 2007 to 2013. Total 13214 height velocity measurements (7724 on boys). OUTCOME MEASURES: Height velocity percentiles (3rd, 10th, 25th, 50th, 75th, 90th and 97th) constructed using LMS chart maker. RESULTS: Age- and gender-specific height velocity percentiles were generated. Median height velocity in girls decreased from 5 to 8 years, increased to a peak of 6.6 cm at 10.5 years and then declined to 0.3 cm at 17.5 years. In boys, median height velocity reduced till 10.5, increased to a peak of 6.8 cms at 13.5 years and then declined to 1cm by 18 years. CONCLUSIONS: Height velocity percentiles in 5-17-year-old urban Indian children were constructed.


Assuntos
Estatura/fisiologia , Desenvolvimento Infantil/fisiologia , Gráficos de Crescimento , Adolescente , Peso Corporal/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Índia/epidemiologia , Estudos Longitudinais , Masculino
5.
Hypertens Res ; 42(6): 845-851, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30587855

RESUMO

Pediatric blood pressure (BP) reference tables are generally based on sex, age, and height and tend to be cumbersome to use in routine clinical practice. In this study, we aimed to develop a new, height-specific simple BP table according to the international child BP reference table based on sex, age and height and to evaluate its performance using international data. We validated the simple table in a derivation cohort that included 58,899 children and adolescents aged 6-17 years from surveys in 7 countries (China, India, Iran, Korea, Poland, Tunisia, and the United States) and in a validation cohort that included 70,072 participants from three other surveys (China, Poland and Seychelles). The BP cutoff values for the simple table were calculated for eight height categories for both the 90th ("elevated BP") and 95th ("high BP") percentiles of BP. The simple table had a high performance to predict high BP compared to the reference table, with high values (boys/girls) of area under the curve (0.94/0.91), sensitivity (88.5%/82.9%), specificity (99.3%/99.7%), positive predictive values (93.9%/97.3%), and negative predictive values (98.5%/97.8%) in the pooled data from 10 studies. The simple table performed similarly well for predicting elevated BP. A simple table based on height only predicts elevated BP and high BP in children and adolescents nearly as well as the international table based on sex, age, and height. This has important implications for simplifying the detection of pediatric high BP in clinical practice.


Assuntos
Pressão Sanguínea , Hipertensão/diagnóstico , Adolescente , Fatores Etários , Área Sob a Curva , Estatura , Criança , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Masculino , Programas de Rastreamento , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores Sexuais
6.
Indian Pediatr ; 54(11): 919-924, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28849765

RESUMO

OBJECTIVE: To validate body composition measurements by Bioelectric Impedance Analysis (BIA) against Dual-Energy X-ray Absorptiometry (DXA) as the reference method in healthy children and adolescents. DESIGN: Cross-sectional. SETTING: Schools in and around Pune city, India. PARTICIPANTS: A random sample of 210 (114 boys, 96 girls) apparently healthy Indian children and adolescents (5-18 y). METHODS: Weight, height, Tanner stage (TS) were recorded. Body composition measures: fat-free mass (FFM), fat mass (FM), lean mass (LM), bone mineral content (BMC) and body fat percentage (%BF) were assessed by BIA and DXA on a single day. Agreement between the methods was estimated by Pearson's correlation, and Bland and Altman analysis. MAIN OUTCOME MEASURES: %BF, FM, FFM, LM, BMC. RESULTS: BIA underestimated %BF by 6.7 (3.7)% as compared to DXA. Mean FFM, BMC and LM by BIA were significantly higher than by DXA (P<0.001). These differences remained similar after adjusting for age, BMI and TS. Mean differences between FFM (-2.32 (1.39) kg), BMC (-0.18 (0.15) kg), and LM (-2.15 (1.34) kg) by DXA and BIA were significant (P<0.01). Correlations between BIA and DXA were 0.92 for %BF, 0.96 for LM and 0.98 for FFM and BMC. Both the methods were similar in identifying normal and overfat children as per their respective cut-offs. CONCLUSION: BIA and DXA techniques are not interchangeable for assessment of body composition. However, BIA may be used in the field/clinical setting preferably with ethnicity specific references.


Assuntos
Absorciometria de Fóton/métodos , Absorciometria de Fóton/normas , Tecido Adiposo/diagnóstico por imagem , Composição Corporal/fisiologia , Água Corporal/diagnóstico por imagem , Impedância Elétrica/uso terapêutico , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Índia/epidemiologia , Masculino
7.
Indian Pediatr ; 54(12): 1005-1011, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-28952454

RESUMO

OBJECTIVE: To create gender-specific percentile curves for percent body fat (%BF) by Bio electrical Impedance Analysis (BIA) for screening adiposity and risk of hypertension in Indian children and generate reference curves for percent fat-free mass (%FFM), muscle mass (%LM) and bone mineral content (BMC) by using bioelectrical impedance. DESIGN: Secondary analysis of data from previous multicenter cross-sectional studies. SETTING: Private schools from five regions of India. PARTICIPANTS: A random sample of 3850 healthy school children (2067 boys) (5-17 yr) from private schools in five major Indian cities. METHODS: Anthropometry, blood pressure (BP) and body composition were measured by bioelectrical impedance. Reference curves were generated by the LMS method. MAIN OUTCOME MEASURES: %BF, %FFM, %LM, BMC and BP. RESULTS: Median %BF increased by 6% from 5 to 13 years of age and declined (around 2%) up to 17 years in boys. In girls, %BF increased by 8% from 5 to 14 years and thereafter declined by 3%. Based upon the risk of hypertension, the new cut-offs of 75th and 85th percentile of %BF were proposed for detecting over fatness and excess fatness in children. Median %FFM was 90% at 5 yrs and decreased till 12 years, and then showed a slight increase to 84% at 17 yrs in boys. In girls, it was 86% at 5 yrs and decreased till 15 yrs, and plateaued at 71.8% at 17 yrs. CONCLUSIONS: Reference curves for percent body fat for Indian children would be useful to screen children for health risk in clinical set up.


Assuntos
Povo Asiático/estatística & dados numéricos , Composição Corporal/fisiologia , Adolescente , Antropometria , Pressão Sanguínea , Criança , Estudos Transversais , Impedância Elétrica , Feminino , Humanos , Índia/epidemiologia , Masculino , Exame Físico/normas , Valores de Referência , Estudantes/estatística & dados numéricos
8.
Indian Pediatr ; 53(1): 39-41, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26840670

RESUMO

OBJECTIVE: To compare lipid parameters between diabetics and controls and to study association between metabolic control and lipid profile. METHODS: Lipid profile and HbA1c were measured (n=80, 39 boys) in diabetic children [age 10.7(3.4) y] and 54 controls, tests repeated after 1 year (in 45 diabetics). RESULTS: Diabetic children had higher mean (SD) LDL-C [95.3(27.7) vs 84.5(26.4) mg/dL], lower HDL-C [48.2 (13.1) vs 53.1(11.9) mg/dl]. Moderate physical activity (P=0.014) protected against high LDL-C levels. HbA1c (P=0.00) predicted total and LDL-C levels. At 1year, 63% showed reduced LDL-C with improving HbA1c; 72% showed increased LDL-C with deteriorated HbA1c. CONCLUSION: Improving metabolic control is cardinal to reduce cardiometabolic risk; physical activity is beneficial.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 1 , Lipídeos/sangue , Adolescente , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/epidemiologia , Estudos de Casos e Controles , Criança , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 1/metabolismo , Feminino , Seguimentos , Humanos , Masculino , Atividade Motora , Fatores de Risco
9.
Indian Pediatr ; 53(11): 990-992, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27889727

RESUMO

OBJECTIVE: To study longitudinal growth in children with type 1 diabetes mellitus. METHODS: Anthropometry, disease duration, insulin regimens and HbA1C recorded from patients with diabetes enrolled in a specialty clinic. RESULTS: 160 children (75 boys; mean (SD) age 9.4 (3.3) y) were enrolled. 35% children had low (<25th centile) height velocity. Disease duration and HbA1C affected height velocity (adjusted for puberty). Children on basal-bolus had higher height velocity Z scores than those on a split mix regimen [(0.5(1.6) vs. -0.3(1.4), P<0.05)]. Children diagnosed before 5 years of age had lowest height velocity. Of the children who reached final height, 53% remained below target height. CONCLUSION: Children with type 1 diabetes mellitus have lower height velocity compared to healthy children; those diagnosed at younger age were at higher risk for growth failure.


Assuntos
Estatura/fisiologia , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 1/fisiopatologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Índia/epidemiologia , Estudos Longitudinais , Masculino
10.
Bone ; 82: 16-20, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25956533

RESUMO

OBJECTIVE: Low bone mineral density has been reported in children and adolescents with type 1 diabetes (T1DM). The aims of this cross-sectional study were to study growth, serum IGF1 concentrations and bone health parameters assessed by Dual Energy X-ray Absorptiometry (DXA). METHODS: Height was measured and converted to Z scores (HAZ). Serum IGF1 concentrations were measured (ELISA) in a subset. Bone mineral content for total body (less head) (TBBMC) and lumbar spine was measured (n=170, 77 boys, 6-16years old) and converted to Z scores using local normative data. RESULT: Mean age was 11.1±3.8years, disease duration was 2.2±2.5years and HbA1C was 10.1±1.8%. Diabetic children were shorter than reference population (HAZ -0.6±1.1); Z scores for height and total body bone area (TBBA) for height were <-2SD in 12% & 6% respectively. Serum IGF1 Z scores were lower amongst group with longer disease duration (-1.58±1.3 vs -2.63±0.7; P=0.037). Disease duration (ß=-0.180, P=0.000) and metabolic control (HbA1C; ß=-0.096, P=0.042) were negative predictors of HAZ and TBBA for height Z in younger children. Using the Molgaard approach, children with longer disease duration had lower HAZ (-0.31±0.92 vs -1.28±1.11; P=0.000; "short bones") and TBBA for height Z scores (0.12±1.62 vs -0.53±0.94; P=0.044; "slender bones"). Older children (tanner stages 4 and 5) had lower BMC and BA as compared to reference population possibly due to delayed growth spurt. CONCLUSION: Longer duration of diabetes was associated with shorter and slender but appropriately mineralized bones. Small and slender bones in diabetic children may increase risk of fragility fractures in the future. This article is part of a Special Issue entitled "Bone and diabetes".


Assuntos
Estatura/fisiologia , Densidade Óssea/fisiologia , Diabetes Mellitus Tipo 1/diagnóstico por imagem , Diabetes Mellitus Tipo 1/epidemiologia , Absorciometria de Fóton , Adolescente , Criança , Estudos Transversais , Feminino , Humanos , Índia/epidemiologia , Masculino
11.
Hypertension ; 68(3): 614-20, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27432869

RESUMO

The identification of elevated blood pressure (BP) in children and adolescents relies on complex percentile tables. The present study compares the performance of 11 simplified methods for assessing elevated or high BP in children and adolescents using individual-level data from 7 countries. Data on BP were available for a total of 58 899 children and adolescents aged 6 to 17 years from 7 national surveys in China, India, Iran, Korea, Poland, Tunisia, and the United States. Performance of the simplified methods for screening elevated or high BP was assessed with receiver operating characteristic curve (area under the curve), sensitivity, specificity, positive predictive value, and negative predictive value. When pooling individual data from the 7 countries, all 11 simplified methods performed well in screening high BP, with high area under the curve values (0.84-0.98), high sensitivity (0.69-1.00), high specificity (0.87-1.00), and high negative predictive values (≥0.98). However, positive predictive value was low for most simplified methods, but reached ≈0.90 for each of the 3 methods, including sex- and age-specific BP references (at the 95th percentile of height), the formula for BP references (at the 95th percentile of height), and the simplified method relying on a child's absolute height. These findings were found independently of sex, age, and geographical location. Similar results were found for simplified methods for screening elevated BP. In conclusion, all 11 simplified methods performed well for identifying high or elevated BP in children and adolescents, but 3 methods performed best and may be most useful for screening purposes.


Assuntos
Determinação da Pressão Arterial/métodos , Saúde da Criança , Hipertensão/diagnóstico , Programas de Rastreamento/métodos , Adolescente , Fatores Etários , Criança , Estudos Transversais , Bases de Dados Factuais , Feminino , Humanos , Hipertensão/epidemiologia , Masculino , Monitorização Fisiológica/métodos , Medição de Risco , Análise e Desempenho de Tarefas
12.
Asia Pac J Clin Nutr ; 24(1): 73-82, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25740745

RESUMO

INTRODUCTION: Diet plays a crucial role for maintaining normal growth and development while optimizing glycemic control in children with diabetes. Dietary restrictions, in a diabetic child's diet may lead to micronutrient deficiencies. OBJECTIVES: To examine dietary nutritional deficiencies of Asian Indian children with Type 1 diabetes mellitus and develop micronutrient-rich recipes suitable for them. METHODS: Anthropometry, diet (3-day recall) of 70 children with diabetes (24 boys) was recorded. Daily nutrient intakes and nutrient content of recipes were estimated using CDIET version 2.0. RESULTS: Mean intake amongst children for energy was 79% of Indian Recommended Dietary Allowance (RDA), protein was 105% RDA, but fat intakes were high (143% RDA). Mean intakes of riboflavin, ß carotene, zinc, iron were less than 50%, and thiamin and calcium were around 60% RDA suggesting a possible multiple micronutrient deficiency. Based on popularly consumed snacks, 20 healthy recipes were devised that can be incorporated in children's diet. Mean energy content of new recipes was similar to routine snacks (281±28 kcal/100 g vs 306±27 kcal/100 g cooked weight). However, the mean vitamin and mineral content of new recipes was significantly higher (p<0.01). There was a five-fold increase in total mineral content (zinc, calcium and iron) and twofold increase in total vitamin content (ß carotene, vitamin C, vitamin B-1, B-2, and B-3) in new recipes compared with the routine snacks. CONCLUSION: Multiple dietary micronutrient deficiencies are observed in diabetic children. Addition of newly developed recipes in their everyday diet may help to enhance micronutrient intakes without increasing their energy load.


Assuntos
Diabetes Mellitus Tipo 1/dietoterapia , Dieta , Comportamento Alimentar , Micronutrientes/administração & dosagem , Adolescente , Criança , Culinária , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Ingestão de Energia , Feminino , Humanos , Índia , Masculino , Micronutrientes/deficiência , Minerais/administração & dosagem , Estado Nutricional , Recomendações Nutricionais , Vitaminas/administração & dosagem
13.
Indian J Endocrinol Metab ; 17(6): 1057-60, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24381884

RESUMO

BACKGROUND AND OBJECTIVES: Growth parameters are important indicators of a child's overall health, and they are influenced by factors like blood glucose control in diabetic children. Data on growth parameters of Indian diabetic children is scarce. This retrospective, cross-sectional, case control study was conducted at diabetes clinic for children at a tertiary care center at Pune, to study growth parameters of diabetic children in comparison with age-gender matched healthy controls and evaluate effect of different insulin regimes and age at diagnosis of diabetes on growth. MATERIALS AND METHODS: ONE TWENTY FIVE DIABETIC CHILDREN (BOYS: 50) and age gender matched healthy controls were enrolled. All subjects underwent anthropometric measurements (standing height and weight). Mean height (HAZ), weight (WAZ) and body mass index (BAZ) for age Z scores were calculated. Diabetes control was evaluated by measuring glycosylated hemoglobin (HbA1C). Statistical analysis was done by SPSS version 12. RESULTS: Mean age of diabetic children and age gender matched controls was 9.7 ± 4.4 years. Diabetic children were shorter (128.3 ± 24.3 cm vs. 133.6 ± 24.7 cm) and lighter (29.2 kg ± 15.3 vs. 31.3 ± 15.4 kg). HAZ (-1.1 ± 1.2 vs. -0.2 ± 0.8) and WAZ (-1.2 ± 1.3 vs. -0.7 ± 1.3) were significantly lower in diabetic children (P < 0.05). Children on both insulin regimes (intensive and conventional) were shorter than controls (HAZ-intensive -1.0 ± 1.0, conventional -1.3 ± 1.3, control -0.2 ± 0.8, P < 0.05). HAZ of children who were diagnosed at <3 years of age was the least (-1.6 ± 1) amongst all diabetic children while those diagnosed after puberty (>14 years) were comparable to healthy controls. CONCLUSIONS: Growth was compromised in diabetic children in comparison to controls. Children diagnosed at younger age need more attention to optimize growth.

15.
Biomacromolecules ; 7(12): 3327-35, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17154460

RESUMO

This paper presents the formation of a novel biomimetic interface consisting of an electrolessly deposited gold film overlaid with a tethered bilayer lipid membrane (tBLM). Self-assembly of colloidal gold particles was used to create an electrolessly deposited gold film on a glass slide. The properties of the film were characterized using field-effect scanning electron microscopy, energy dispersive spectroscopy, and atomic force microscopy. Bilayer lipid membranes were then tethered to the gold film by first depositing an inner molecular leaflet using a mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[3-(2-pyridyldithio)propionate], 1,2-di-O-phytanyl-sn-glycero-3-phosphoethanolamine (DPGP), and cystamine in ethanol onto a freshly prepared electrolessly deposited gold surface. The outer leaflet was then formed by the fusion of liposomes made from DPGP or 1,2-dioleoyl-sn-glycero-3-phosphocholine on the inner leaflet. To provide functionality, two membrane biomolecules were also incorporated into the tBLMs: the ionophore valinomycin and a segment of neuropathy target esterase containing the esterase domain. Electrochemical impedance spectroscopy, UV/visible spectroscopy, and fluorescence recovery after pattern photobleaching were used to characterize the resulting biomimetic interfaces and confirm the biomolecule activity of the membrane. Microcontact printing was used to form arrays of electrolessly deposited gold patterns on glass slides. Subsequent deposition of lipids yielded arrays of tBLMs. This approach can be extended to form functional biomimetic interfaces on a wide range of inexpensive materials, including plastics. Potential applications include high-throughput screening of drugs and chemicals that interact with cell membranes and for probing, and possibly controlling, interactions between living cells and synthetic membranes. In addition, the gold electrode provides the possibility of electrochemical applications, including biocatalysis, bio-fuel cells, and biosensors.


Assuntos
Eletrônica/métodos , Ouro , Bicamadas Lipídicas/química , Fosfolipídeos/química , Coloides , Eletroquímica/métodos , Microscopia Eletrônica de Varredura , Modelos Moleculares , Conformação Molecular , Soluções
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA