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L H Allen

Publications and source records attributed to L H Allen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Examining the gender gap in nutrition: an example from rural Mexico.

Gender differences in nutrient and food intake were examined in Mexican Nutrition CRSP (Collaborative Research Support Program) infants (N = 75), preschoolers (N = 80), and school children (N = 91). No significant gender differences in dietary quality or quantity were seen for infants and preschoolers. For school children, the contribution of various foods to total energy intake (dietary quality) was also quite similar for girls and boys. Equity in dietary quality remained even under conditions of economic and demographic stress. Nevertheless, school girls consumed significantly less energy per day than boys (-300 kcal/d or 1.3 mJ/d), and less of all micronutrients examined. Gender differences in estimated basal metabolic rates of school children were slight (-20 kcal/d), and body composition and size were similar. When energy intakes were expressed as a percent of estimated requirement (calculated from age, sex and weight using WHO/FAO/UNU equations), intakes were adequate and not significantly different between girls (mean = 111%) and boys (mean = 113%). Playground observations showed girls to be less active than boys, which may reflect both cultural and biological influences. Apparently due to this lower activity, school girls consumed less energy, and may have been at much higher risk than boys of micronutrient deficiency. The lower food intakes of girls did not appear to be due to purposeful dietary discrimination, but rather to culturally patterned sex roles involving lower activity.

Basal Metabolism↗
PubMed1997

Zinc supplementation reduced morbidity, but neither zinc nor iron supplementation affected growth or body composition of Mexican preschoolers.

In rural Mexico and in many developing countries micronutrient deficiencies, growth stunting, and morbidity from infectious diseases are highly prevalent in young children. We assessed the extent to which growth stunting could be reversed and the number of infectious disease episodes reduced by zinc and/or iron supplementation. In a double-blind, randomized community trial 219 Mexican preschoolers were supplemented with either 20 mg Zn as zinc methionine, 20 mg Fe as ferrous sulfate, 20 mg Zn + 20 mg Fe, or a placebo. After 12 mo, plasma zinc increased significantly in the two zinc-treated groups, and plasma ferritin was significantly higher in the two iron-treated groups. There was no effect of treatments on growth velocity or body composition. Children in both zinc-supplemented groups had fewer episodes of disease (zinc alone, 3.9 +/- 0.3; zinc+iron, 3.7 +/- 0.4; placebo, 4.6 +/- 0.5; P < 0.03), including diarrhea (zinc alone, 0.7 +/- 0.1; zinc+iron, 0.8 +/- 0.1; placebo, 1.1 +/- 0.2; P < 0.01). Zinc and zinc+iron supplements reduced morbidity but had no effect on growth or body composition.

Body Composition↗
PubMed1997

Vitamin B-12 deficiency is very prevalent in lactating Guatemalan women and their infants at three months postpartum.

Vitamin B-12 status was evaluated in 113 Guatemalan women and their infants at 3 mo of lactation. Plasma vitamin B-12 was deficient or low in 46.7% of the mothers, and holotranscobalamin II (holo TC II) concentrations were low in 32.3%, which may indicate vitamin B-12 malabsorption. Only 9% had deficient or low plasma folate. Breast milk vitamin B-12 was low in 31%, and negatively correlated with infant urinary methylmalonic acid (UMMA, r = -0.22, P < 0.05, n = 88); UMMA was elevated in 12.2% of the infants, indicating vitamin B-12 deficiency. Mothers of the infants with elevated UMMA had significantly lower concentrations of vitamin B-12 in their breast milk compared with mothers of infants with normal UMMA concentrations (410.7 +/- 247.7 vs. 705.3 +/- 487.5 pmol/L, P = 0.05, n = 87). Mean maternal dietary intake of vitamin B-12 was significantly correlated with plasma vitamin B-12 (r = 0.20, P = 0. 05, n = 94) and was the main determinant of plasma vitamin B-12 in a linear regression model. Determinants of maternal holo TC II concentrations included dietary intake of vitamin B-12 and Giardia lamblia infection. There were no statistically significant determinants of infant UMMA concentrations. We conclude that vitamin B-12 deficiency is highly prevalent in these lactating women and is associated with depletion of the vitamin in their infants. The cause of the maternal deficiency is unknown, but malabsorption exacerbated by low dietary intake of the vitamin is a possibility.

Adult↗
PubMed1997

Pregnancy and iron deficiency: unresolved issues.

Iron deficiency and iron deficiency anemia are prevalent among pregnant women. The extent to which iron deficiency affects maternal and neonatal health is uncertain. Existing data suggest that maternal iron deficiency anemia may be associated with adverse outcomes, including preterm delivery and higher maternal mortality. Further research is needed on the maternal and neonatal benefits of iron supplementation during pregnancy.

Anemia, Iron-Deficiency↗
PubMed1996

Determinants of body size perceptions and dieting behavior in a multiethnic group of hospital staff women.

OBJECTIVE: This study was designed to identify determinants of body size perceptions and their relationship to dietary behavior in a multiethnic group of women. DESIGN: A single interview consisting of the Massara and Stunkard body image cards (1979) and questionnaires on sociocultural background, anthropometry, and dieting history were administered to volunteers from the staff of a hospital. SUBJECTS: The sample was a convenience sample of 186 women representing a range of staff positions recruited from Methodist Hospital in Brooklyn, NY; 174 completed the study. Data on 150 women are presented in this article. RESULTS: Height and weight-for-height were stronger predictors of accuracy of perceived body size than ethnicity. Tall, slight women were more likely to overestimate and short, heavy women were more likely to underestimate actual body size. Ethnicity had an interactive effect with height as taller European Americans were more likely to perceive their body size as larger than actual compared with Afro-Caribbeans and African Americans. Women with a history of dieting were more likely to overestimate their size and to view it as different from what is perceived as attractive to others. APPLICATIONS/CONCLUSIONS: Based on the results, we conclude that body size is a stronger predictor of accuracy of perceived body size than ethnicity; and dieters overestimate their body size and believe it to be heavier than their social group would prefer.

Black or African American↗
PubMed1995

A role for MARCKS, the alpha isozyme of protein kinase C and myosin I in zymosan phagocytosis by macrophages.

Myristoylated, alanine-rich C-kinase substrate (MARCKS) is a lipopolysaccharide-induced protein kinase C (PKC) substrate that has been proposed to regulate actin-membrane interactions, as well as actin structure at the membrane. We studied the distribution of MARCKS, the alpha isozyme of PKC (PKC alpha), and myosin I in lipopolysaccharide-treated peritoneal macrophages ingesting zymosan particles. MARCKS, PKC alpha, and myosin I colocalized with F-actin and talin in the cortical cytoplasm adjacent to forming phagocytic cups. After particle ingestion was completed, myosin I, F-actin, and talin were no longer enriched in the vicinity of the phagosome. By contrast, MARCKS and PKC alpha remained associated with the phagosome membrane until after acquisition of the lysosomal marker Lamp-1. Vinculin was not detected on phagosomes at any time point examined. Phagocytosis of zymosan was accompanied by rapid and sustained phosphorylation of MARCKS. Inhibitors of PKC reduced zymosan binding to the macrophage surface and blocked the focal accumulation of F-actin, talin, phosphotyrosine-containing proteins, MARCKS, and PKC alpha beneath attached particles. We propose that PKC-dependent phosphorylation is an early signal required for zymosan phagocytosis and that MARCKS and PKC alpha have a role in phagosome maturation. The colocalization of F-actin and MARCKS at the cytoplasmic face of the nascent phagosome reinforces the hypothesis that MARCKS regulates actin structure at the membrane. Our data also suggest that myosin I functions as a mechanical motor during particle uptake.

Actins↗
PubMed1995

Functional expression of the renal organic cation transporter and P-glycoprotein in Xenopus laevis oocytes.

The hypothesis that P-glycoprotein (P-gp) mediates the renal secretion of organic cations was tested by functional expression of mRNAs in the Xenopus laevis oocyte system. Efflux of 2'-deoxytubercidin (dTub), a substrate for the renal organic cation transporter (OCT) but not for P-gp, was enhanced by injection of renal mRNA but not by injection of mRNA from P-gp-overexpressing cells (MDCK cells transduced with the cDNA for human MDR1). The functional capacity of the MDCK-MDR mRNA was established by its ability to reduce the steady-state uptake of a classical P-gp substrate, vinblastine. Thus, these data indicate OCT and P-gp to be distinct entities. The Xenopus oocyte system provides a functional approach to further characterize the OCT.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Vitamin B-12 deficiency and malabsorption are highly prevalent in rural Mexican communities.

Vitamin B-12 status of rural Mexicans was evaluated in two studies, 6 y apart. In the first, a single blood sample was collected from children and adults, including pregnant and lactating women. Prevalence of deficient plasma vitamin B-12 values ranged from 19% to 41% among groups, but plasma folate status was normal in all individuals. Breast milk vitamin B-12 concentration was low in 62% of samples. The second study was conducted in 219 children aged 18-36 mo in five communities, whose prevalence of deficient and low plasma vitamin B-12 concentrations, respectively, was 8% and 33% on entry, 3% and 22% 6 mo later, and 7% and 29% 12 mo later. Prevalence of low holotranscobalamin II concentrations, indicating malabsorption of the vitamin, averaged 18-40% across the three same periods. Both vitamin B-12 status indicators differed significantly between communities. The widespread vitamin B-12 deficiency was probably caused by malabsorption, perhaps exacerbated by low dietary intake and, for young children, maternal depletion of the vitamin.

Adult↗
PubMed1995

Malnutrition and human function: a comparison of conclusions from the INCAP and nutrition CRSP studies.

The overall objective of both the Institute of Nutrition of Central America and Panama (INCAP) studies and the Nutrition Collaborative Research Support Program (CRSP) was to determine if marginal malnutrition affects human function. The conclusions from the two studies were consistent, notably that growth stunting occurs early in life and is accompanied by functional impairments. These consequences of early malnutrition persist later in life. The comparison of INCAP and Nutrition CRSP results also illustrates that the Guatemalan children were more malnourished and stunted than those in Kenya, Mexico or Egypt and that this greater degree of stunting occurs before 18 months of age. Even the Atole did not bring the average size of supplemented children in Guatemala up to those of the unsupplemented children in the CRSP populations. It is also likely that their functional potential was not realized fully by supplementation. The CRSP studies provide evidence of multiple micronutrient deficiencies associated with poor growth and function and it is probable that these associations exist in Guatemala as well. The overall conclusion is that our attention should be directed to determining the adequacy of micronutrient status in the perinatal period and to the development of approaches that prevent early growth failure.

Adolescent↗
PubMed1995

The use of Vicryl mesh (polyglactin 910) for implantation of hydroxyapatite orbital implants.

Hydroxyapatite (HA) implants currently are most commonly wrapped in donor sclera before implantation to facilitate placement within the orbit and allow attachment of the extraocular muscles. Although the risk of acquiring a transmittable disease through donor sclera is extremely low, some individuals remain concerned about receiving nonautologous material. As an alternative to sclera, autologous temporalis fascia, or autologous fascia lata, we have been wrapping HA in "Vicryl mesh" before insertion into the orbit. The Vicryl mesh-wrapped implant goes into the socket readily, allows one to easily attach the extraocular muscles, and has no risk of transmittable disease. In addition, the Vicryl mesh is readily available at most hospitals and is dissolvable.

Durapatite↗
PubMed1995

Vicryl-mesh wrap for the implantation of hydroxyapatite orbital implants: an animal model.

OBJECTIVE: To evaluate host fibrovascularization of hydroxyapatite orbital implants wrapped in sclera or in Vicryl (polyglactin 910) mesh in a rabbit model. NUMBERS: Eight adult New Zealand white rabbits that received hydroxyapatite orbital implants wrapped in homologous donor sclera (four animals) or Vicryl mesh (four animals). INTERVENTIONS: The rabbits had one eye enucleated and then received a 12-mm hydroxyapatite implant wrapped in sclera or Vicryl mesh. Magnetic resonance imaging (MRI) and bone scintigraphy were done to assess host fibrovascularization of the implant 4, 8, 12 and 20 weeks after implantation. Two animals (one in each group) were killed at each of these times, and the implant was removed for histopathological examination. MAIN OUTCOME MEASURES: Enhancement on MRI, uptake on bone scintigraphy, fibrovascularization seen on histopathological examination. RESULTS: The degree of fibrovascularization was substantial in all the specimens but appeared greater in the Vicryl-mesh-wrapped implants in the first 12 weeks after implantation on both histopathological and MRI studies. At 20 weeks these findings were similar in the two groups. A granulomatous foreign-body giant-cell reaction to both the Vicryl mesh and the implant itself was present up to 8 weeks after implantation. Bone scans showed only grade 1+ activity in all the implants. CONCLUSIONS: Host fibrovascularization in the rabbit appears to occur to a greater degree in Vicryl-mesh-wrapped hydroxyapatite implants than in those wrapped in donor sclera during the first 12 weeks after implantation. Vicryl mesh appears to be an acceptable alternative wrap for the hydroxyapatite implant, eliminating the need for donor sclera and its potential risks of transmissible diseases.

Animals↗
PubMed1994

Vitamin B12 metabolism and status during pregnancy, lactation and infancy.

This overview of vitamin B12 metabolism and requirements during the continuum of pregnancy and lactation has identified several gaps in our knowledge. More information is needed concerning the roles of the different transcobalamins during pregnancy and lactation, including their impact on placental and mammary transfer of cobalamin and their effect on intestinal absorption in the infant. Knowledge is needed about the relative importance of maternal stores and current dietary intake on fetal storage of the vitamin, and on its concentration in breast milk. Because there is some evidence that infant's urinary methylmalonic acid excretion is reduced by intakes slightly higher than the current RDA, the adequacy of the current RDA for vitamin B12 during infancy should be verified. Finally, it is possible that vitamin B12 deficiency is more common in pregnant and lactating women and their young children in developing countries than has been recognized previously, due primarily to malabsorption. It is important to confirm whether or not this is the case, in view of its potential impact on infant neurobehavioral development and the relative ease with which supplements of the vitamin could be provided.

Developing Countries↗
PubMed1994

Assessment of the impact of rising carbon dioxide and other potential climate changes on vegetation.

The projected doubling of current levels of atmospheric carbon dioxide concentration ([CO(2)]) during the next century along with increases in other radiatively active gases have led to predictions of increases in global air temperature and shifts in precipitation patterns. Additionally, stratospheric ozone depletion may result in increased ultraviolet-B (UV-B) radiation incident at the Earth's surface in some areas. Since these changes in the Earth's atmosphere may have profound effects on vegetation, the objectives of this paper are to summarize some of the recent research on plant responses to [CO(2)], temperature and UV-B radiation. Elevated [CO(2)] increases photosynthesis and usually results in increased biomass, and seed yield. The magnitude of these increases and the specific photosynthetic response depends on the plant species, and are strongly influenced by other environmental factors including temperature, light level, and the availability of water and nutrients. While elevated [CO(2)] reduces transpiration and increases photosynthetic water-use efficiency, increasing air temperature can result in greater water use, accelerated plant developmental rate, and shortened growth duration. Experiments on UV-B radiation exposure have demonstrated a wide range of photobiological responses among plants with decreases in photosynthesis and plant growth among more sensitive species. Although a few studies have addressed the interactive effects of [CO(2)] and temperature on plants, information on the effects of UV-B radiation at elevated [CO(2)] is scarce. Since [CO(2)], temperature and UV-B radiation may increase concurrently, more research is needed to determine plant responses to the interactive effects of these environmental variables.

Journal Article↗