Publications by authors named "Leah J Barrett"

Describing the early life associations between infectious disease episodes and growth, cognitive development, and vaccine response in the first 2 years of life is one of the primary goals of the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study. To collect high-resolution data during a critical early period of development, field staff visit each study participant at their house twice weekly from birth to 2 years of age to collect daily reported illness and treatment data from caregivers. Detailed infectious disease histories will not only allow us to relate the overall burden of infectious disease with the primary outcomes of the study, but will also allow us to describe the ages at which infectious diseases have the greatest effect on child health.

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A seroepidemiological study was performed to determine the seroprevalence of Cryptosporidium in human immunodeficiency virus (HIV)-infected adults and local university students in the Limpopo Province, South Africa. Using a custom anti-C. parvum immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), the seroprevalence of Cryptosporidium was found to be significantly higher (75.

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Background & Aims: Prolonged episodes of acute diarrhea (ProD; duration 7-13 days) or persistent diarrhea (PD; duration ≥14 days) are important causes of undernutrition, yet the epidemiology and nutritional impact of ProD are poorly understood.

Methods: We conducted a 10-year cohort study of 414 children from a Brazilian shantytown who were followed from birth; data were collected on diarrhea, enteric pathogens, and anthropometry.

Results: During 1276 child-years of observation, we recorded 3257 diarrheal episodes.

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Background: This study evaluates the effects of retinol on intestinal barrier function, growth, total parasites, and Giardia spp infections in children in northeastern Brazil.

Subjects And Methods: The study was a double-blind, randomized placebo-controlled trial (http://clinicaltrials.gov; register no.

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Worldwide, contaminated drinking water poses a major health threat, particularly to child development. Diarrhoea represents a large part of the water-related disease burden and enteric infections have been linked to nutritional and growth shortfalls as well as long-term physical and cognitive impairment in children. Previous studies detailed the frequency of infection and the consequences for child health in a shanty town in north-east Brazil.

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Background: Intestinal cells grown in microgravity produce a three-dimensional tissue assembly, or "organoid," similar to the human intestinal mucosa, making it an ideal model for enteric infections such as cryptosporidiosis.

Methods: HCT-8 cells were grown in a reduced-gravity, low-shear, rotating-wall vessel (RWV) and were infected with Cryptosporidium parvum oocysts. Routine and electron microscopy (EM), immunolabeling with fluorescein-labeled Vicia villosa lectin and phycoerythrin-labeled monoclonal antibody to a 15-kD surface-membrane protein, and quantitative polymerase chain reaction (qPCR) using probes for 18s rRNA of C.

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Angiotensin II (ANG II) has been described in the regulation of intestinal secretion and absorption via angiotensin subtype 1 (AT(1)) and AT(2) receptors, respectively, in rats. We investigated the role that ANG II plays in the rabbit ileal-loop model of Clostridium difficile infection. Expression of AT(1), the more abundant ANG II receptor, was demonstrated in ileal loops, and an AT(1) receptor blocker, losartan, inhibited hypersecretion induced by C.

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Polymorphisms in the apolipoprotein E (APOE) have constituted the major rationale to identify potential risk groups for developing late-onset Alzheimer's disease and help to predict recovery of cognitive function after brain injury. However, the APOE impact on cognitive development in children living in poor areas of the developing world, where we have discovered profound significant associations of early childhood diarrhea (at 0-2 y) with lasting impairments of growth, cognition, and school performance, is not known. Therefore, we conducted APOE genotyping in 72 Brazilian shantytown children under active surveillance since birth, using purified DNA extracted from buccal cell samples.

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Background: Helicobacter pylori diagnosis and susceptibility profile directs the applicability of recommended treatment regimens in our setting. To our knowledge, there is no published data on the culture and local susceptibility pattern of Helicobacter pylori in the Philippines.

Methods: 52 dyspeptic adult patients undergoing endoscopy from the Outpatient Gastroenterology clinic of the University of the Philippines-Philippine General Hospital underwent multiple gastric biopsy and specimens were submitted for gram stain, culture, antimicrobial sensitivity testing, rapid urease test and histology.

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To examine the association of intestinal barrier function with vitamin A deficiency and whether supplementation of micronutrients improves intestinal function and/or linear growth, height-for-age z-score (HAZ), concentrations of serum retinol and zinc, and intestinal permeability were determined in a cross-sectional sample of 75 children in northeastern Brazil. Effects of vitamin A and supplementation of zinc on intestinal permeability and growth were also determined comparing results before and after treatment in 20 children and age-matched controls. Lactulose:mannitol (L/M) permeability ratios inversely correlated with serum retinol concentrations (r = -0.

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To examine the importance of intestinal inflammation in the diagnosis and pathogenesis of human cryptosporidiosis, stools of healthy adult volunteers before and after experimental infection were tested for fecal lactoferrin, interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha). Stool samples of Brazilian children with well-defined Cryptosporidium infection, with or without diarrhea, were also tested for IL-8 and TNF-alpha. Only one of the 14 volunteers challenged with Cryptosporidium had increased fecal lactoferrin.

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We determined age-specific Helicobacter pylori seropositivity rates of 166 children and 39 mothers in an urban shantytown in northeast Brazil. Seropositivity rates increased from 23.1% at 0 to 11 months of age to only 39.

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