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Biomedical subjects

S E Barlow

Publications and source records attributed to S E Barlow.

7 recordsLinked to original sources
PubMed2005

Preparation and in situ characterization of surfaces using soft landing in a Fourier transform ion cyclotron resonance mass spectrometer.

Mass-selected peptide ions produced by electrospray ionization were deposited onto fluorinated self-assembled monolayer surfaces (FSAM) surfaces by soft landing using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially designed for studying interactions of large ions with surfaces. Analysis of the modified surface was performed in situ by combining 2-keV Cs+ secondary ion mass spectrometry with FT-ICR detection of the sputtered ions (FT-ICR-SIMS). Regardless of the initial charge state of the precursor ion, the SIMS mass spectra included singly protonated peptide ion, peptide fragment ions, and peaks characteristic of the surface in all cases. In some experiments, multiply protonated peptide ions and [M + Au]+ ions were also observed upon SIMS analysis of modified surfaces. For comparison with the in situ analysis of the modified surfaces, ex situ analysis of some of the modified surfaces was performed by 25-keV Ga+ time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The ex situ analysis demonstrated that a significant number of soft-landed peptide ions remain charged on the surface even when exposed to air for several hours after deposition. Charge retention of soft-landed ions dramatically increases the ion yields obtained during SIMS analysis and enables very sensitive detection of deposited material at less than 1% of monolayer coverage. Accumulation of charged species on the surface undergoes saturation due to coulomb repulsion between charges at close to 30% coverage. We estimated that close to 1 ng of peptide could be deposited on the spot area of 4 mm2 of the FSAM surface without reaching saturation.

Journal Article↗
PubMed2005

Preliminary psychometric evaluation of the Child Health Ratings Inventory (CHRIs) and Disease-Specific Impairment Inventory-Hematopoietic Stem Cell Transplantation (DSII-HSCT) in parents and children.

PURPOSE: To describe the initial results of the Child Health Ratings Inventory (CHRIs), 20-item generic health-related quality of life (HRQL) instrument and the 10-item disease-specific (DS) module, the Disease Specific Impairment Inventory-Hematopoietic Stem Cell Transplantation (DSII-HSCT), for children and adolescents, ages 5-18 years and their parents following HSCT. STUDY DESIGN: Using cross sectional design, 122 children with a median age of 11 years (range 5.0-18 years) completed the questionnaire (CHRIs + DSII-HSCT) with research assistance. Seventy-four parents independently completed a parallel version of the questionnaire; health care providers assigned a global clinical severity rating. RESULTS: The generic core includes four domains: physical, role, and emotional functioning, and energy. The DS module has three domains: worry, hassles, and body image. The Cronbach's alpha for parents and for older children (8 years and over) exceeded 0.70 for all generic and DS domains. While the range of alpha coefficients was lower for younger children, ages 5-7 year, only the alpha coefficient for one domain (energy) was less than 0.70. The instrument satisfactorily discriminated between clinically important groups: those early in the transplant process (< 6 months) versus those later (> 12 months) and by provider-assigned clinical severity ratings. CONCLUSION: results suggest that the CHRIs generic core and its DSII-HSCT module is a promising measure of HRQL after pediatric HSCT. Although parent and child reports were moderately correlated and revealed complementary results, the unique perspectives of both raters provide a more complete picture of HRQL. Longitudinal application is underway to further characterize the measurement properties of the CHRIs and to determine the instrument's responsiveness and sensitivity to change over time in this vulnerable population.

Adolescent↗
PubMed2000

Prevalence of abnormal serum aminotransferase values in overweight and obese adolescents.

OBJECTIVES: (1) To determine the prevalence of abnormal liver enzymes in overweight and obese adolescents and (2) to determine the relationship of alcohol ingestion and serum antioxidants to the presence of abnormal liver enzymes in overweight and obese adolescents. METHODS: Serum alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase levels were measured in 2450 children between the ages of 12 and 18 years, enrolled in the National Health and Examination Survey, cycle III (NHANES III). Obesity was defined as a body mass index >95th percentile for age and sex. Overweight was defined as a body mass index >85th percentile for age and sex. Nutritional intake was assessed by 24-hour dietary recall and food frequency questionnaires. Serum antioxidants were measured by high-pressure liquid chromatography. RESULTS: Sixty percent of adolescents with elevated ALT levels were either overweight or obese. Overall, 6% of overweight adolescents had elevated ALT levels (odds ratio: 3.4 [95% CI: 3.5-12.8]). Ten percent of obese adolescents had elevated ALT levels (odds ratio: 6.7 [95% CI: 3.5-12.8]). In addition, approximately 1% of obese adolescents demonstrated ALT levels over twice normal. Approximately 50% of of obsese adolescents who reported modest alcohol ingestion (4 times per month or more) had elevated ALT levels (odds ratio: 10.8, 95% CI: 1.5-77). Other factors associated with elevated ALT levels in overweight and obese adolescents include increased age, elevated glycolated hemoglobin, elevated triglycerides, and decreased levels of serum antioxidants-vitamin E, beta-carotene, and vitamin C. CONCLUSION: Overweight and obesity are the most common findings in adolescents with elevated ALT levels. Even modest alcohol consumption may significantly increase the likelihood of obese adolescents developing obesity-related liver disease.

Adolescent↗
PubMed1999

Health-related quality of life in pediatric bone marrow transplant survivors: according to whom?

Historically, health-related quality of life (HRQL) assessment in pediatrics, including the few validated instruments in pediatric oncology, has been based on proxy reporting, relying primarily on parental assessment. Children have been deemed incapable of providing consistent and reliable information about their level of functioning or state of well-being. Previous studies have been hampered by either limited or poor correlation among the proxy reporters, i.e., teachers, parents and physicians, and in comparisons to disease severity. Simply stated, proxy reporters have greater agreement about what the child can do vs. what the child thinks or feels. Comparisons among proxy reporters have been hindered also by a lack of parallel content in the instruments used, which may result in poorly congruent assessments simply because the instruments measure different constructs. In addition to the measurement issues, the emotional milieu of the parent, particularly the mother, has been shown to influence assessments of the child's functioning. Maternal distress, marital adjustment and health locus of control all co-vary with reports of the child's behavior. What, then, is the proxy reporter telling us about the child? We conducted a cross-sectional study of school-aged pediatric bone marrow transplant (BMT) patients at our institution to evaluate children's self-reported HRQL and functional status. We formally tested the Child Health Rating Inventories (CHRIs), a recently developed generic health-status measure, with its companion measure, the Disease Impairment Inventories-Bone Marrow Transplant (DSII-BMT). Separate questionnaires were administered to patients, parents and physicians at a scheduled outpatient visit after BMT. The questionnaires were designed to have parallel content. All responses were confidential. The psychometric properties of the CHRIs and DSII-BMT are reported elsewhere. In brief, the responses of all raters were reliable, based on measurements of internal consistency. The children's self-reported health status was correlated significantly with the physicians' disease severity rating (DSR) across all generic and disease-specific domains. In contrast, parental reports of child health status were not correlated significantly with the DSR for disease-specific problems or the child's pain. Parental ratings deviated most from the children's ratings within the dimensions of mental health and quality of life (p < 0.001). For the entire sample, parental ratings were significantly lower than the children's ratings. Within the subgroup "early after transplant (<6 months)", parental ratings were significantly lower than the children's self-reports in all categories. In the subgroup ">12 months after transplant", with the exception of mental health and quality of life, parental scores were the same as or higher than the children's ratings. Our results confirm previous studies that the parental reporting of children's health status is a complex construct and that valuable information can be elicited directly from the children. Further research is needed to substantiate these findings, particularly in longitudinal applications with adequate sample sizes.

Bone Marrow Transplantation↗
PubMed1998

Obesity evaluation and treatment: Expert Committee recommendations. The Maternal and Child Health Bureau, Health Resources and Services Administration and the Department of Health and Human Services.

OBJECTIVES: The development of recommendations for physicians, nurse practitioners, and nutritionists to guide the evaluation and treatment of overweight children and adolescents. METHODS: The Maternal and Child Health Bureau, Health Resources and Services Administration, the Department of Health and Human Services convened a committee of pediatric obesity experts to develop the recommendations. RESULTS: The Committee recommended that children with a body mass index (BMI) greater than or equal to the 85th percentile with complications of obesity or with a BMI greater than or equal to the 95th percentile, with or without complications, undergo evaluation and possible treatment. Clinicians should be aware of signs of the rare exogenous causes of obesity, including genetic syndromes, endocrinologic diseases, and psychologic disorders. They should screen for complications of obesity, including hypertension, dyslipidemias, orthopedic disorders, sleep disorders, gall bladder disease, and insulin resistance. Conditions that indicate consultation with a pediatric obesity specialist include pseudotumor cerebri, obesity-related sleep disorders, orthopedic problems, massive obesity, and obesity in children younger than 2 years of age. Recommendations for treatment evaluation included an assessment of patient and family readiness to engage in a weight-management program and a focused assessment of diet and physical activity habits. The primary goal of obesity therapy should be healthy eating and activity. The use of weight maintenance versus weight loss to achieve weight goals depends on each patient's age, baseline BMI percentile, and presence of medical complications. The Committee recommended treatment that begins early, involves the family, and institutes permanent changes in a stepwise manner. Parenting skills are the foundation for successful intervention that puts in place gradual, targeted increases in activity and targeted reductions in high-fat, high-calorie foods. Ongoing support for families after the initial weight-management program will help families maintain their new behaviors. CONCLUSIONS: These recommendations provide practical guidance to pediatric clinicians who evaluate and treat overweight children.

Adolescent↗
PubMedDate not supplied

Methodologic issues in the conduct and interpretation of pediatric effectiveness research.

Effectiveness research represents a number of methodologic challenges not shared with randomized, controlled clinical trials. This practice-based research attempts to translate clinical practices to a wide variety of different practice settings and situations and to diverse patient subgroups. However, because study designs most often used in the conduct of effectiveness research limit the ability to establish firm causal links between medical care and outcomes, it is important to address key methodologic features to generate sound, useable findings. Such features include selection of appropriate outcome measures (with a priori hypotheses linking care to the outcomes chosen), specification of appropriate primary sampling unit, specification of unit of analysis, establishment of appropriate comparison groups, and case-mix adjustment. Conduct of this type of research in pediatrics presents a number of unique methodologic concerns that either do not apply in adult medicine or are particularly acute in pediatrics. To alert policy makers and funders to the unique aspects of pediatric health services research and to provide guidance for the conduct and interpretation of pediatric effectiveness studies, we have organized and described the methodologic issues associated with the specific type of pediatric care under study (eg, specific disease-prevention, "bundled" care for chronic disease, care for problems with social etiologies, etc). We conclude with a summary of the methodologic steps that are critical to the conduct of sound effectiveness research in pediatrics.

Child↗