Neutrophil activation is the most important initial immune defense against invading microbes in newborn infants. The reduced neutrophil migration and uncontrolled regulation of reactive oxygen species (ROS) production observed in neonates, could result in a diminished infectious response or in tissue damage. The aims were to study neutrophil chemotactic response towards IL-8 and fMLP in term neonates; to examine neutrophil receptor expression involved in adhesion, migration, phagocytosis and complement after stimulation with IL-8 and fMLP in term neonates; and to investigate neutrophil production of ROS, induced by PMA and E.coli, after preincubation with IL-8 and fMLP in term and preterm newborn infants. Comparisons were made to neutrophils from healthy adults. Chemotaxis was distinguished from randomly migrating neutrophils, and the neutrophil migration distance and the number of migrating neutrophils per distance was evaluated. Neutrophils were labeled with antibodies to cell surface antigens (CD11b, CD18, CD65, CD15S, CD162, CD44, CD35, CD88, CD181, CD182 and CD64) after stimulation with IL-8 and fMLP. After preincubation of neutrophils with fMLP or IL-8 and stimulation with PMA or E.coli, respiratory burst was detected. The same analyses were also made in preterm infants (median 25+3weeks GA; range 23+0–29+2) within 3 days postnatal age. Neutrophils from neonates exhibited different migratory and receptor responses to IL-8 and fMLP, with a diminished response towards IL-8 in term newborn infants in terms of reduced chemotaxis and modulation of receptors involved in adhesion, chemotaxis, complement and phagocytosis as compared to adults. fMLP reduced PMA- and E.coli-induced respiratory burst in neutrophils from term neonates and adults. The reduced respiratory burst by fMLP may be a mechanism for reducing the detrimental effects of uncontrolled inflammation. Although a similar burst reduction was observed in preterm infants born >25 weeks GA with fMLP, a diminished neutrophil respiratory burst modulation in very preterm infants cannot be excluded and requires further studies at different gestational and postnatal ages.

Jealousy is understood as a system of physiological, behavioral, and emotional responses, yet few studies have examined these aspects of jealousy simultaneously in infants. Further, jealousy paradigms have not been examined as a potential stressor in infancy and thus typical cortisol reactivity and regulation patterns in response to jealousy paradigms have not been observed. In addition, the contribution of attachment security to infant expressions of jealousy has been vastly understudied. The present study seeks to fill the current gaps in the infant jealousy literature by investigating quantitative and qualitative changes in infant jealousy across the first two years of life. Data was collected longitudinally and mother- infant dyads were asked to participate when infants were 12- months and 24-months of age. Associations between behavioral jealousy responses, baseline EEG activity, stress reactivity and attachment security were examined. Differences in approach behaviors and behavioral arousal were found across conditions and were consistent with previous studies (Hart & Carrington, 2002; Mize & Jones, 2012). Findings relating to EEG activity pointed to a relationship between left EEG asymmetry and global approach behaviors across time. Cortisol reactivity was found to be associated with attachment security but reactive cortisol concentrations compared to baseline cortisol concentrations do not indicate that the paradigm was an effective stressor. Attachment security was found to be associated with proximity behaviors in 12- month olds but not 24-month olds. Finally, a linear regression revealed that attachment security, EEG asymmetry, and cortisol reactivity at 12-months are significant predictors of behavioral jealousy responses at 24-months. Changes in behavioral and physiological measures across time indicate that jealousy continues to develop during the second year of life but may have different underlying processes than the processes that contribute to jealousy expression in 12-month-olds. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

The Hispanic birthweight paradox, whereby Hispanic women exhibit a comparable or lower risk of bearing a low birthweight infant than their white counterparts despite relative socioeconomic disadvantage, has been observed across a number of research studies. However, the majority of evidence for the paradox has focused on Hispanics in aggregate form or on populations with primarily Mexican ancestry and has relied largely on outcome measures with important methodological shortcomings. Furthermore, studies have identified the variation of birthweight risk among Hispanics by nativity, maternal education and neighborhood composition, but the evidence has been scarce and inconsistent. The overall goal of this dissertation was to investigate the Hispanic health paradox with relation to measures of birthweight and infant size in births to women residing in New York City aged 20 years and older, using birth records for years 2003 through 2007 collected by the Office of Vital Statistics of the New York City Department of Health and Mental Hygiene (N=460,881). The main outcomes of interest in this study were mean birthweight, low birthweight (LBW, defined as < 2500 grams versus ≥ 2500 grams) and small for gestational age (SGA, calculated as the 10th percentile for birthweight at each week of gestational age and by sex). Multilevel logistic models with random effects were used to estimate odds ratios for the association between race/ethnicity and measures of birthweight and infant size, while controlling for individual-level and contextual factors and accounting for the correlation between observations within the same neighborhood. Analyses were conducted with Hispanics as an aggregate group as well as with race/ethnic-nativity subgroups. In addition, effect measure modification by maternal education and by neighborhood proportion of Hispanic population (NPHP) were examined. This research confirmed the Hispanic paradox in SGA analyses for Hispanics overall and for both U.S.-born and foreign-born Hispanics, but not in analyses with LBW or with mean birthweight. As compared to white women, black women exhibited 50% greater risk (OR:1.50;95%CI:1.45,1.55) and Hispanic women comparable risk (OR:1.03;95%CI:1.00,1.06) of having an SGA infant, in a fully adjusted model. With regard to LBW, the risk was more than double for black women (OR:2.25;95%CI:2.16,2.35) and close to 50% greater for Hispanic women (OR:1.46;95%CI:1.40,1.53) as compared to that of their white counterparts. In addition, the mean birthweight of infants born to Hispanic women was significantly lower compared to those born to white women. Furthermore, the relationship between race/ethnicity and all three measures of birthweight and infant size varied by maternal nativity status (p<0.0001), with infants of foreign-born women experiencing more favorable outcomes relative to their U.S.-born counterparts. The paradox with SGA was also apparent across most Hispanic race/ethnicity-nativity subgroups, The odds were greatest among black and Puerto Rican women overall (OR:1.52;95%CI:1.47,1.57 and OR:1.17;95%CI:1.13,1.22, respectively) and lowest among Mexican and South American women overall, (OR:0.91;95%CI:0.87,0.95 and OR:0.85;95%CI:0.80,0.89) as compared to white women in a fully adjusted model. The odds of SGA for infants born to Dominicans, Central Americans and Cubans in the fully adjusted model were similar to those born to whites. In addition, SGA varied by maternal nativity status (p<0.0001), with more favorable SGA odds observed among infants of most foreign-born women, as compared to whites. The exception was U.S.-born Puerto Ricans who consistently exhibited elevated risk of SGA relative to whites. The association of race/ethnicity-nativity with SGA varied by maternal educational attainment (p<0.0001), but the influence varied by subgroup. The observed advantage of foreign birth was stronger among less educated women of all Hispanic subgroups other than Puerto Ricans and Cubans. Similarly, the variation of SGA risk by neighborhood proportion of Hispanic population (NPHP) differed across subgroups (p<0.0001). NPHP did not appear to influence the association between race/ethnicity-nativity and SGA in a consistent pattern, but among black women and US-born Puerto Rican women greater NPHP was associated with a higher risk of SGA. Findings from this study underscore the importance of using SGA an accurate measure of infant size and of conducting analyses disaggregating race/ethnicity and nativity subgroups. Future research should focus on factors that contribute to the resilience of Hispanic subgroups in the face of adverse economic circumstances, such as the role of social support networks and acculturation. Greater understanding of the salubrious circumstances that lower the risk of adverse birth outcomes has major public health benefits, especially for a wide-ranging population of mothers, Hispanic and non-Hispanic, and their infants.

Thesis (M. A. (Clinical Psychology)) -- University of Limpopo, 2003 / Refer to document

Le propos de ce travail de thèse est d’examiner le développement de la formation de catégories de visages, par l’étude des préférences visuelles des nourrissons dans la première année de vie. Nous avons cherché à préciser les mécanismes de formation des préférences visuelles en les intégrant dans le cadre théorique développé par Valentine (1991), le face-space. Nous avons proposé de lier ces préférences à la manière dont l’expérience perceptive des nourrissons avec différentes catégories de visages va structurer l’espace de représentation des visages. De manière générale, nous avons postulé que les nourrissons présenteront des préférences pour les visages proches de la tendance centrale (i.e., prototype) du face-space. Nous avons mis en évidence une tendance des nourrissons de 0 à 6 mois à présenter un biais pour des visages d’adultes par rapport à des visages de nourrissons (Etudes 1 et 2), les premiers correspondant à une catégorie de visages prépondérante de l’environnement des nourrissons, là où les seconds correspondent à une catégorie de visages peu rencontrée. Ce biais pour la familiarité s’est avéré disparaitre à 9 et 12 mois (Etude 3). Ces préférences liées à la familiarité pourraient être liées à une forme de fausse reconnaissance du visage des proches des nourrissons, issue de la surreprésentation de ces visages dans le quotidien des nourrissons. Ce pattern de préférences n’a en revanche pas été retrouvé lorsque des nourrissons de 3 à 12 mois ont été confrontés à des visages d’enfants ou de nourrissons (Etudes 4 et 5), les résultats montrant plutôt une préférence pour les visages les moins familiers, relativement à l’expérience des nourrissons. Nous avons ensuite étudié les capacités de catégorisation de nourrissons de 9 et 12 mois pour des visages de différentes catégories d’âges, i.e., adulte, enfant, nourrisson (Etude 6). Les nourrissons de 12 mois ont formé des catégories discrètes des visages d’adulte et de nourrissons d’une part, et d’enfants et de nourrissons d’autre part. Les nourrissons de 9 mois en revanche ont montré un pattern plus asymétrique en ce qu’ils ont formé une représentation des visages d’enfants excluant un nouveau visage de nourrisson, et une représentation des visages de nourrissons incluant un nouveau visage d’enfant. Les nourrissons ayant tous une expérience de la crèche, donc des visages de nourrissons, cette asymétrie pourrait être liée à une influence de la connaissance de cette catégorie de visage. Dans une dernière étude (Etude 7) nous avons cherché à montrer plus directement le lien entre préférences visuelles et proximité par rapport au prototype, chez des nourrissons humains de 12 mois et des nourrissons macaques de 3 mois (Macaca mulatta). La mise en évidence de préférences liées à la distance par rapport au prototype chez ces deux populations suggère la présence d’un mécanisme commun aux deux espèces conduisant à la formation de préférences visuelles pour les visages. / The purpose of this work is to examine of the development of face category formation using infants’ visual preferences. We investigated the mechanisms leading to differential face preferences by integrating them in the theoretical framework developed by Valentine (1991), the face-space. We proposed that the way perceptual experience shape the structure of the face-space is a determinant of infants’ face preferences. We postulated that faces close to the central tendency of the face-space (i.e., prototype) will be preferred. We first reported a bias to look more toward adult faces than infant faces from birth to 6 month of age (Studies 1 and 2). Adult faces correspond to a frequently encountered category while infant faces represent a less frequently encountered category. We also showed a downturn of this familiarity bias as infants grow older (Study 3). The preferences showed by younger infants might be linked to a form of false recognition of the caregivers’ faces, due to the massive exposure to these faces. This pattern of preferences was not found in 3-to 12-month-olds presented with child and infant faces (Studies 4 and 5). Conversely, infants showed a tendency to prefer the less familiar faces, depending on their perceptual experience. We then studied 9- and 12-month-olds’ abilities to form categories of faces differing by age, i.e., adult, child, and infant faces, (Study 6). Twelve-month-olds formed discrete categories of adult and infant faces in one hand, and of child and infants faces on the other hand. Nine month-olds showed an asymmetric pattern of behavior, forming categories of child faces that exclude a new infant face, and categories of infant faces that include a new child face. All these infants being exposed to infant faces via nursery, the asymmetry might stem from the influence of the knowledge of this category of faces. In the last study (Study 7), we tried to provide more direct evidences of the link between face preferences and the distance from the prototype in two different populations: 12-month-old human infants, and 3-month-old macaque infants (Macaca mulatta). Preferences for faces close to the prototype in both species suggest a common mechanism leading to face preferences.

Abstract not available

Thesis (Ph. D.)--University of Missouri--Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 202-211). Also available on the Internet.

The present study provides information about the relationships between parental reactions to their children‘s expression of negative emotions at 8 months, parent-infant attachment at 12 and 15 months and parental reactions to children‘s negative emotional expressions at 24 months, and as well as the extent to which all of these variables predict children‘s emotional expressivity as toddlers at 24 months, after controlling for infant emotional reactivity. Analyses showed that parental responses to infant negative emotions, insecure attachment and parental responses to toddlers‘ negative emotions as well as infant emotional reactivity all made independent contributions to predicting toddler negative (vs. positive) affect. Only insecure infant-parent attachment, not parental socialization or infant emotional reactivity, predicted toddler flat (vs. expressive) affect. The inclusion of fathers in this study is important not only to clarify how mothers and fathers differ in socializing their children‘s negative emotions, but also to have a more complete study of how emotional expressivity develops. Analyses conducted separately by parent gender revealed differences in the relationship between parental socialization, attachment and emotional expressivity across mothers and fathers, indicating that researchers should continue to include fathers in studies of socialization of emotional expressivity. / text

A sustainable primary prevention strategy for infant iron deficiency anemia (IDA) was implemented and evaluated in a community with at-risk infants in northern Quebec, Canada. Communication strategies were used to promote iron-rich complementary food rather than iron-fortified formula, which can interfere with breastfeeding practice. This food-based approach has been successfully implemented in developing countries, but has not been applied in an industrialized country setting. / Mass media (i.e., radio dialogues, key messages, print material, point-of-purchase grocery store display) and interpersonal (i.e., homemade baby food cooking activity) communication strategies were developed in collaboration with community members and implemented in partnership with an existing community program. Reach and exposure of the strategies were measured using a questionnaire administered to a post-intervention sample (n = 45). Sales of promoted iron-rich infant food were examined pre- and post-intervention period. A repeat cross-sectional design was used for the impact evaluation. Two groups of mothers with infants, aged 7-10 months at Time 1 (n = 32) and Time 2 (n = 22) were interviewed. Outcome variables were infants' total iron and complementary food iron intakes measured by two 24-hour recalls. Secular trends in infants' hemoglobin values and milk type consumption were examined in the study community and two comparison communities. / Multiple communication channels increased awareness of IDA and influenced self-reported use of iron-rich infant food. Iron-rich infant food sales increased from pre- to post-intervention (p < 0.05). Complementary food intake iron increased between Time 1 (3.2 +/- 0.8 mg) and Time 2 (4.4 +/- 1.1 mg) (p < 0.05). The proportion of infants with anemia (hemoglobin < 110 g/L) significantly decreased from the period before (37.2%) to during (14.3%) the intervention (p < 0.05). No significant difference was found for this variable within the comparison communities. The proportion of infants receiving iron-fortified formula in the study community did not differ between Time 1 and Time 2, but increased from Time 1 (55%) to Time 2 (73%) (p < 0.05) in the comparison communities, indicating an erosion of breastfeeding practice. / These results suggest the effectiveness of communication strategies to improve infant iron nutrition in a community with good access to iron-rich infant food. The potential for this strategy in other communities warrants further investigation.

The objectives of this research were to determine the prevalence of anemia, and identify risk factors for anemia, in 9-month-old Cree infants living in northern Quebec. The prevalence of anemia (hemoglobin <110 g/L) was 25--32%, depending on the study sample. Iron deficiency was present in 28.2% of infants who could be classified and 14.4% had iron deficiency anemia. Fewer than 2% of infants had low birth weight (<2500 g) so most infants should have been born with adequate iron stores. One cause of anemia that was identified was a diet that was low in iron. Only 15.1% of infants were reported by guardians to eat meat daily and 28.5% were reported to never eat meat. Infants who were breastfed or cow's milk fed did not obtain sufficient iron for effective erythropoiesis. Compared with formula that was predominantly iron fortified, the odds ratio (OR) for anemia was 7.9 (95% CI 3.4--18.2) for breast milk and 5.0 (95% CI 2.0--12.7) for cow's milk. When milk type was controlled for, weight gain since birth was significantly associated with microcytic erythrocytes (OR comparing the highest tertile of weight gain to the lowest tertile 2.9, 95% CI 1.2--6.6). This indicates that fast-growing infants were not meeting their iron needs for growth. Another risk factor for anemia that was identified was common childhood infections. The prevalence of anemia among infants reported as recently unwell with an infection was higher than among infants reported as recently well (31.1% vs. 19.0%, chi2 = 4.27, p = 0.039). The prevalence of elevated blood lead was 2.7% and is not a major public health problem. No evidence for vitamin A deficiency was found. Serum retinol was positively associated with all iron status indicators. Cree infants who were given supplements containing vitamin A had a lower prevalence of anemia (hemoglobin <105 g/L) (10.8% vs 23.2%, chi2 = 5.97, p = 0.015). These results suggest a role for vitamin A in iron metabolism. To prevent anemia in aboriginal i