Biomedical subjects
Publications and source records attributed to E Pollitt.
Nucleotide sequence analysis of the 4.3 kbp BamHI-N fragment of the fowlpox virus (FPV) genome revealed that it encodes 7 proteins with homology to vaccinia virus (VV) E11L, E10R, O1L, O3L, I1L, I2L and I3L encoded proteins. No evidence of FPV homolog of VV O2L could be found.
This paper reviews three experiments on the effects of an overnight and morning fast on attention and memory processes among 9-11-y-old children. Two of the experiments focused on middle-class, well-nourished boys and girls in the United States: the third involved boys from low-income families with and without nutritional risk in Huaraz, Peru. All experiments used the same crossover design and followed similar experimental procedures to control the subjects' intakes and motor activity during the study period. The children were admitted to a research center on two different evenings, approximately 7 d apart. After arrival the children ate dinner, played table games or watched television, and went to bed. They were awakened at 0730 and, by design, were either served breakfast (approximately 2301 kJ) or not. At 1100 they took psychologic tests that assessed recall from working memory and competence in discriminating visual stimuli. At 1200 the children were discharged. The consequences of the overnight and morning fast, particularly among the children who were nutritionally at risk, included slower stimulus discrimination, increased errors, and slower memory recall. We propose that these alterations result from a state of metabolic stress in which homeostatic mechanisms work to maintain circulating glucose concentrations.
This article provides an overview of a school breakfast program implemented in 1993 in the Peruvian Andes. The program, designed by the Instituto de Investigación Nutricional in Lima and supported by the government of Peru, constitutes a clear departure from previous school feeding programs, which were heavily politicized and poorly documented. From the program's inception, nutritionists, managers, and social scientists have collaborated to produce a sound nutritional design, efficient distribution mechanisms, and effective evaluation methods. During the program's first year, controlled evaluations conducted in several Andean regions documented improved dietary intake and a significant decline in the prevalence of anemia. An educational evaluation also found improved verbal skills, higher school attendance, and lower dropout rates among recipients of the school breakfast. The results have prompted the Peruvian government to continue supporting the program, thus setting a new standard for the effective management of social expenditure in the context of economic adjustment.
In this supplement, the papers presented at the International Symposium on Breakfast and Performance in Napa, CA in 1995 are summarized and integrated with data published since that time. In particular, the focus is on issues of research design, measurements, mechanisms, potential effect modifiers (eg, age), and relevance for public policy. No definitive conclusions can be drawn from the existing data on either the long- and short-term benefits of breakfast on cognition and school learning or the mechanisms that mediate this relation. The pooled data suggest that omitting breakfast interferes with cognition and learning, an effect that is more pronounced in nutritionally at-risk children than in well-nourished children. At the very least, breakfast consumption improves school attendance and enhances the quality of the students' diets.
The title of a 1930s article asked the question, "Stupidity or Hookworm?" In this article, the authors discuss research that attempts to answer the question of whether intestinal worms--namely, hookworm, whipworm, and roundworm--harm the mental performance of their hosts. After introducing the biology and epidemiology of intestinal worms, the authors present the historical background to the problem. They review research from the 1910s through the 1990s; there is evidence that high intensities of worms can affect mental performance, but not all dewormed children show improved performance. They discuss the mechanisms of how worms might affect the mind.
Does short-term supplementary feeding during infancy and childhood have long-lasting effects? In 1986, 334 children aged 6-60 mo living on rural tea plantations in West Java, Indonesia, participated in a 3-mo randomized trial to test the effects of a dietary supplement providing approximately 1672 kJ (400 kcal) energy/d, with about the same nutrient density as local foods. We returned to the same communities in 1994 and enrolled 231 (125 supplemented, 106 control) of the original subjects in a follow-up study of the long-term effects of supplementation. We assessed these subjects by using several measures: anthropometry, iron status, information processing, Peabody Picture Vocabulary Test, word fluency, and an arithmetic test. The supplemented group showed no differences from those in the control group. However, when the analysis was limited to subjects who had received the supplement before the age of 18 mo (n = 73), the supplemented children performed better than control children on the Sternberg test of working memory (decision time intercept: probe absent, P = 0.002; probe present, P = 0.053). After considering possible confounders, we concluded that the supplementation during infancy was responsible for the difference. This finding shows that supplementation can have long-lasting effects on a specific domain if the child receives it at the appropriate stage of development.
Existing data suggest that iron deficiency anemia (IDA) is a risk factor for poor educational performance in schoolchildren. The synergistic effect of IDA in combination with other forms of malnutrition and other risk factors may affect educational performance more strongly. Thus, IDA and its effect on educational performance should be studied in the context of other risk factors.
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The data presented here come from a 20-year study conducted in a rural area of Guatemala. Data on early biological indicators, graduated parameters of social structure, and preschool cognition were combined into a risk scale and analyzed in relation to primary school grade attainment and adolescent psychoeducational test performance. Similar to empirical relations reported in industrialized countries, performance declined as the number of risk factors to which a subject was exposed increased. More important, primary education was observed to buffer the effects of early risk for a subset of subjects. Subjects at high risk who stayed in school performed significantly better than subjects with similar levels of risk who completed fewer than 4 years of primary school.
OBJECTIVE: To determine whether successful deworming for 6 months in children with high levels of Ascaris improves physical growth. SUBJECTS: Two hundred twenty-eight children (mean age, 9.7 years) in a highland Indian town in Guatemala. DESIGN: Children were randomly assigned to receive albendazole or placebo at baseline and 12 weeks. Children and field workers were both blind to the group assignment. OUTCOME MEASURES: Children's heights, weights, and mid-upper-arm circumferences were measured at baseline and 12 and 24 weeks. Fecal egg counts were taken at 0, 2, 12, 14, and 24 weeks to estimate the helminth burden (eggs per gram of feces [epg]). RESULTS: Baseline helminth prevalences were Ascaris, 91%, and Trichuris, 82%. Ascaris intensities were high: half of the children had moderate burdens (10 000 to 50 000 epg), and 25% had heavy burdens ( > 50 000 epg). Trichuris burdens were light (72% < 1000 epg). The albendazole and placebo groups did not differ at baseline in epg, age, anthropometry, or socioeconomic status. The two rounds of treatment successfully reduced the Ascaris burdens but had less effect on Trichuris. At 6 months the treatment group showed a small gain in weight (0.18 kg) compared with the placebo group but no improvement in height or mid-upper-arm circumference. CONCLUSIONS: The successful removal of ascaris in a population of school-aged children with relatively high loads may have modest effects on weight gain. Ascaris is one of the most common infections in school-aged children, but its effect on the host may be less than that of other helminths.
The study assessed the effects of supplementary feeding over 180 consecutive days on iron status of infants and toddlers at six tea plantation in West Java, Indonesia. The design used was a clinical trial: two eohorts (i.e., 12 and 18 months old children) and three treatment groups (i.e., energy + micronutrient, micronutrient alone, and placebo) per cohort. Every day except Sunday, the infants attended day-care centers. Twenty four centers and 136 infants were selected. The infants were screened for weight and length and those meeting the criteria (i.e., < -1 SD of length-for-age, and between -1 and -2 SD of weight-for-length of the NCHS reference) were included. The experimental unit was the day-care centers (DCC), where each DCC was randomly assigned to one of the three treatment. As expected, groups of energy + micronutrient and micronutrient alone of the 12 months cohort experienced a significant upward shift in hemoglobin, ferritin and TS and a downward change in FEP, while the values for the group of placebo remain about the same as at base line. In the first 6 month of treatments, the ANOVA for each iron indicator yielded significant main effects of treatment (P < 0.01) and for Hb with (P = 0.059) on 12 months cohort. On the other hand, the main effects of treatment on hemoglobin, TS, ferritin and FEP were not significant for the 18 months cohort. In the second 6 months of treatments, the only significant of the treatment effect (P < 0.01) was in serum ferritin on 18-month cohort. Under these circumstances, energy has a positive role in improving iron stores. It is likely that the equilibrium of hemoglobin and each iron indicators were reached in 6 months of treatment except ferritin still continued to increase up to 12 month. The effects of treatment on the improvement of iron status was stronger in 12 months than in 18 months.
This article reviews selectively the literature on the effects of breakfast on cognition and school performance. The focus is on studies published in refereed journals after 1978 that tested those effects on well-nourished and nutritionally at-risk children. In at-risk subjects (defined by clinical history and anthropometry), a morning and overnight fast had adverse effects on cognition, particularly the speed of information retrieval in working memory. Contradictions in the data from different studies prevent definitive conclusions on whether well-nourished children experience similar functional deficits. Nonetheless, available information suggests that brain function is sensitive to short-term variations in the availability of nutrient supplies. Moreover, well-conducted evaluations suggest that the availability of feeding programs in public schools throughout the academic year increases the probability that children will eat breakfast and improve their educational status.
The Cali Study involved the random assignment of 301 malnourished children to be exposed to one (CT1, n = 113), two (CT2, n = 64), three (CT3, n = 62) or four (CT4, n = 62) 9-mo periods of a multifocal day care-based intervention (i.e., education, health and nutrition). The ages at which the intervention was initiated for Groups CT4, CT3, CT2 and CT1 were 3.5, 4.2, 5.2 and 6.1 y, respectively. After the experimental phase, children were followed up in elementary school until they were 10.4 y old. Our secondary data analyses show that children who were exposed at an earlier age and for a longer period of time showed the highest degree (P < or = 0.05) of improvement in weight and linear growth during the pre-school period. These improvements in physical growth could no longer be detected 3 y after the termination of the intervention.
The effects of early supplementary feeding on cognition are investigated using data collected during two periods in four Guatemalan villages. The first was the Institute of Nutrition of Central America and Panama (INCAP) longitudinal study from 1969 to 1977 and the second was a cross-sectional follow-up of former participants carried out in 1988-1989. The principal objective of these studies was to assess the differential effect of two dietary supplements, Atole containing 163 kcal/682 kJ and 11.5 g protein per cup or 180 mL and Fresco containing 59 kcal/247 kJ and 0 g protein per cup, that were given to mothers, infants and young children. Performance was assessed on a battery of psychoeducational and information processing tests that were administered during adolescence. Consistent differences between groups were observed on psychoeducational tests. Subjects receiving Atole scored significantly higher on tests of knowledge, numeracy, reading and vocabulary than those given Fresco. Atole ingestion also was associated with faster reaction time in information processing tasks. In addition, there were significant interactions between type of dietary supplement and socioeconomic status (SES) of subjects. In Atole villages, there were no differences in performance between subjects in the lowest and highest SES categories. On the other hand, performance in Fresco villages was best in the highest compared with the lowest SES group. After close scrutiny of alternative hypotheses, it is concluded that dietary changes produced by supplementation provide the strongest explanation for the test performance differences observed in the follow-up between subjects exposed to Atole and those exposed to Fresco supplementation.
Most of the correlational and experimental studies that have tested the hypothesis that mild-to-moderate protein-energy malnutrition (PEM) has an adverse effect on cognitive development disregarded the potential confounder effect of micronutrients. This omission may have been a critical flaw in study design because it is now recognized that iron deficiency increases the probability of deviations in the trajectory of children's motor and mental development from a normal developmental path. This paper discusses two frequently cited studies on the effects of PEM on neurointegrative and cognitive development and proposes that neither study can discard the hypothesis that effects attributed to protein and energy deficiency are, instead, determined by iron deficiency.
The efficacy of iron supplementation for iron-deficient subjects is in no doubt. However, the assumption that iron supplementation of iron-replete subjects is harmless may not be valid. We have studied the effect of iron supplementation on growth rate in 47 iron-sufficient young children (12-18 months) in Indonesia. The children were randomly assigned either ferrous sulphate (3 mg/kg daily) or placebo every day for 4 months. Before treatment the length, weight, and arm circumference of the two groups were similar. During the 4 months of supplementation the rate of weight gain was significantly greater in the placebo group than in the iron-supplemented group (0.106 [SE 0.010] vs 0.070 [0.011] kg every 2 weeks, p = 0.02). The rates of gain in length and arm circumference did not differ significantly by treatment. There were no differences between the groups in rates of respiratory and gastrointestinal infections. These results suggest that iron supplementation of iron-replete children may retard their growth.