Assessing infant exposure to persistent organic pollutants via dietary intake in Australia

Persistent organic pollutants (POPs) including polybrominated diphenyl ethers (PBDEs); organochlorine pesticides (OCPs); and polychlorinated biphenyls (PCBs) persist in the environment, bioaccumulate, and pose a risk of causing adverse human health effects. Typically, exposure assessments undertaken by modeling existing intake data underestimate the concentrations of these chemicals in infants. This study aimed to determine concentrations of POPs in infant foods, assess exposure via dietary intake and compare this to historical exposure. Fruit purees, meat and vegetables, dairy desserts, cereals and jelly foods (n = 33) purchased in 2013 in Brisbane, Australia were analyzed. For OCPs and PCBs, concentrations ranged up to 95 pg/g fw and for PBDEs up to 32 pg/g fw with most analytes below the limit of detection. Daily intake is dependent on type and quantity of foods consumed. Consumption of a 140 g meal would result in intake ranging from 0 to 4.2 ng/day, 4.4 ng/day and 13.3 ng/day, for OCPs, PBDEs and PCBs, respectively. PBDEs were detected in 3/33 samples, OCPs in 9/33 samples and PCBs in 13/33 samples. Results from this study indicate exposure for infants via dietary (in contrast to dust and breast milk) intake in Australia contribute only a minor component to total exposure.

Persistent organic pollutants in matched breast milk and infant faeces samples

Assessing blood concentration of persistent organic pollutants (POPs) in infants is difficult due to the ethical and practical difficulties in obtaining sufficient quantities of blood. To determine whether measuring POPs in faeces might reflect blood concentration during infancy, we measured the concentrations of a range of POPs (i.e. polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs)) in a pilot study using matched breast milk and infant faecal samples obtained from ten mother-child pairs. All infants were breast fed, with 8 of them also receiving solid food at the time of faecal sampling. In this small dataset faecal concentrations (range 0.01-41ngg-1 lipid) are strongly associated with milk concentrations (range 0.02-230ngg-1 lipid). Associations with other factors generally could not be detected in this dataset, with the exception of a small effect of age or growth. Different sources (external or internal) of exposure appeared to directly influence faecal concentrations of different chemicals based on different inter-individual variability in the faeces-to-milk concentration ratio Rfm. Overall, the matrix of faeces as an external measure of internal exposure in infants looks promising for some chemicals and is worth assessing further in larger datasets.

Epithelial sodium channel in airway epithelium of the newborn infant : Implications for postnatal pulmonary adaptation

The aim of the present thesis was to study the role of the epithelial sodium channel (ENaC) in clearance of fetal lung fluid in the newborn infant by measurement of airway epithelial expression of ENaC, of nasal transepithelial potential difference (N-PD), and of lung compliance (LC). In addition, the effect of postnatal dexamethasone on airway epithelial ENaC expression was measured in preterm infants with bronchopulmonary dysplasia (BPD). The patient population was formed of selected term newborn infants born in the Department of Obstetrics (Studies II-IV) and selected preterm newborn infants treated in the neonatal intensive care unit of the Hospital for Children and Adolescents (Studies I and IV) of the Helsinki University Central Hospital in Finland. A small population of preterm infants suffering from BPD was included in Study I. Studies I, III, and IV included airway epithelial measurement of ENaC and in Studies II and III, measurement of N-PD and LC. In Study I, ENaC expression analyses were performed in the Research Institute of the Hospital for Sick Children in Toronto, Ontario, Canada. In the following studies, analyses were performed in the Scientific Laboratory of the Hospital for Children and Adolescents. N-PD and LC measurements were performed at bedside in these hospitals. In term newborn infants, the percentage of amiloride-sensitive N-PD, a surrogate for ENaC activity, measured during the first 4 postnatal hours correlates positively with LC measured 1 to 2 days postnatally. Preterm infants with BPD had, after a therapeutic dose of dexamethasone, higher airway epithelial ENaC expression than before treatment. These patients were subsequently weaned from mechanical ventilation, probably as a result of the clearance of extra fluid from the alveolar spaces. In addition, we found that in preterm infants ENaC expression increases with gestational age (GA). In preterm infants, ENaC expression in the airway epithelium was lower than in term newborn infants. During the early postnatal period in those born both preterm and term airway epithelial βENaC expression decreased significantly. Term newborn infants delivered vaginally had a significantly smaller airway epithelial expression of αENaC after the first postnatal day than did those delivered by cesarean section. The functional studies showed no difference in N-PD between infants delivered vaginally and by cesarean section. We therefore conclude that the low airway epithelial expression of ENaC in the preterm infant and the correlation of N-PD with LC in the term infant indicate a role for ENaC in the pathogenesis of perinatal pulmonary adaptation and neonatal respiratory distress. Because dexamethasone raised ENaC expression in preterm infants with BPD, and infants were subsequently weaned from ventilator therapy, we suggest that studies on the treatment of respiratory distress in the preterm infant should include the induction of ENaC activity.

Matrix proteinases in lung injury in the preterm infant

During inflammation, excess production and release of matrix proteinases, including matrix metalloproteinases (MMPs) and serine proteinases, may result in dysregulated extracellular proteolysis leading to development of tissue damage. Pulmonary inflammation may play an important role in the pathogenesis of lung injury in the preterm infant. The aims of this study were to evaluate involvement of MMPs and serine proteinase trypsin in acute and chronic lung injury in preterm infants and to study the role of these enzymes in acute lung injury by means of an animal model of hyperoxic lung injury. Molecular forms and levels of MMP-2, -8, and -9, and their specific inhibitor, tissue inhibitor of metalloproteinases (TIMP)-2, as well as trypsin were studied in tracheal aspirate fluid (TAF) samples collected from preterm infants with respiratory distress. Expression and distribution of trypsin-2 and proteinase-activated receptor 2 (PAR2) was examined in autopsy lung specimens from fetuses, from preterm infants with respiratory distress syndrome (RDS) or bronchopulmonary dysplasia (BPD), and from newborn infants without lung injury. We detected higher MMP-8 and trypsin-2 and lower TIMP-2 in TAF from preterm infants with more severe acute respiratory distress. Infants subsequently developing BPD had higher levels of MMP-8 and trypsin-2 early postnatally than did those who survived without this chronic lung injury. Immunohistochemically, trypsin-2 was mainly detectable in bronchial epithelium, but also in alveolar epithelium, and its expression was strongest in prolonged RDS. Since trypsin-2 is potent activator of PAR2, a G-protein coupled receptor involved in inflammation, we studied PAR2 expression in the lung. PAR2 co-localized with trypsin-2 in bronchoalveolar epithelium and its expression was significantly higher in bronchoalveolar epithelium in preterm infants with prolonged RDS than in newborn controls. In the experimental study, rats were exposed to >95% oxygen for 24, 48, and 60 hours, or room air. At 48 hours of hyperoxia, MMP-8 and trypsin levels sharply increased in bronchoalveolar lavage fluid, and expression of trypsin appeared in alveolar epithelium, and MMP-8 predominantly in macrophages. In conclusion, high pulmonary MMP-8 and trypsin-2 early postnatally are associated with severity of acute lung injury and subsequent development of BPD in preterm infants. In the injured preterm lung, trypsin-2 co-localizes with PAR2 in bronchoalveolar epithelium, suggesting that PAR2 activated by high levels of trypsin-2 is involved in lung inflammation associated with development of BPD. Marked increase in MMP-8 and trypsin early in the course of experimental hyperoxic lung injury suggests that these enzymes play a role in the pathogenesis of acute lung injury. Further exploration of the roles of trypsin and MMP-8 in lung injury may offer new targets for therapeutic intervention.

Mother-Infant Antibodies to Pneumococcal Polysaccharides and Proteins : Transfer and Persistence of Maternal Antibodies and Development of Vaccine-Induced and Naturally Acquired Antibodies in Infants

Symptomless nasopharyngeal carriage of Streptococcus pneumoniae (pneumococcus) is very common in young children. Occasionally the carriage proceeds into mild mucosal diseases, such as sinusitis or acute otitis media, or into serious life-threatening diseases, such as pneumonia, sepsis or meningitis. Each year, up to one million children less than five years of age worldwide die of invasive pneumococcal diseases (IPD). Especially in the low-income countries IPD is a leading health problem in infants; 75% of all IPD cases occur before one year of age. This stresses the need of increased protection against pneumococcus in infancy. Anti-pneumococcal antibodies form an important component in the defence against pneumococcal infection. Maternal immunisation and early infant immunisation are two possible ways by which potentially protective antibody concentrations against pneumococci could be achieved in early infancy. The aim of this thesis is to increase the knowledge of antibody mediated protection against pneumococcal disease in infants and young children. We investigated the transfer of maternal anti-pneumococcal antibodies from Filipino mothers to their infants, the persistence of the transferred antibodies in the infants, the immunogenicity of the 23-valent pneumococcal polysaccharide vaccine (PPV) in infants and the response of the children to a second dose of PPV at three years of age. We also investigated the development of antibodies to pneumococcal protein antigens in relation to culture-confirmed pneumococcal carriage in infants. Serum samples were collected from the mothers, the umbilical cords and from the infants at young age as well as at three years of age. The samples were used to determine the antibody concentrations to pneumococcal serotypes 1, 5, 6B, 14, 18C and 19F, as well as to the pneumococcal proteins PspA, PsaA, Ply, PspC, PhtD, PhtDC and LytC by the enzyme immunoassay. The findings of the present study confirm previously obtained results and add to the global knowledge of responses to PPV in young children. Immunising pregnant women with PPV provides the infants with increased concentrations of pneumococcal polysaccharide antibodies. Of the six serotypes examined, serotypes 1 and 5 were immunogenic already in infants. At three years of age, the children responded well to the second dose of PPV suggesting that maternal and early infant immunisations might not induce hyporesponsiveness to polysaccharide antigens after subsequent immunisations. The anti-protein antibody findings provide useful information for the development of pneumococcal protein vaccines. All six proteins studied were immunogenic in infancy and the development of anti-protein antibodies started early in life in relation to pneumococcal carriage.

The descriptive epidemiology of congenital and acquired cryptorchidism in a UK infant cohort.

INTRODUCTION: Recent studies in other European countries suggest that the prevalence of congenital cryptorchidism continues to increase. This study aimed to explore the prevalence and natural history of congenital cryptorchidism in a UK centre. METHODS: Between October 2001 and July 2008, 784 male infants were born in the prospective Cambridge Baby Growth Study. 742 infants were examined by trained research nurses at birth; testicular position was assessed using standard techniques. Follow-up assessments were completed at ages 3, 12, 18 and 24 months in 615, 462, 393 and 326 infants, respectively. RESULTS: The prevalence of cryptorchidism at birth was 5.9% (95% CI 4.4% to 7.9%). Congenital cryptorchidism was associated with earlier gestational age (p<0.001), lower birth weight (p<0.001), birth length (p<0.001) and shorter penile length at birth (p<0.0001) compared with other infants, but normal size after age 3 months. The prevalence of cryptorchidism declined to 2.4% at 3 months, but unexpectedly rose again to 6.7% at 12 months as a result of new cases. The cumulative incidence of "acquired cryptorchidism" by age 24 months was 7.0% and these cases had shorter penile length during infancy than other infants (p = 0.003). CONCLUSIONS: The prevalence of congenital cryptorchidism was higher than earlier estimates in UK populations. Furthermore, this study for the first time describes acquired cryptorchidism or "ascending testis" as a common entity in male infants, which is possibly associated with reduced early postnatal androgen activity.

UK guidance on the initial evaluation of an infant or an adolescent with a suspected disorder of sex development

It is paramount that any child or adolescent with a suspected disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD. If there is any doubt, the case should be discussed with the regional team. In most cases, particularly in the case of the newborn, the paediatric endocrinologist within the regional DSD team acts as the first point of contact. The underlying pathophysiology of DSD and the strengths and weaknesses of the tests that can be performed should be discussed with the parents and affected young person and tests undertaken in a timely fashion. This clinician should be part of a multidisciplinary team experienced in management of DSD and should ensure that the affected person and parents are as fully informed as possible and have access to specialist psychological support. Finally, in the field of rare conditions, it is imperative that the clinician shares the experience with others through national and international clinical and research collaboration. © 2011 Blackwell Publishing Ltd.

Modeling the development of pronunciation in infant speech acquisition.

Pronunciation is an important part of speech acquisition, but little attention has been given to the mechanism or mechanisms by which it develops. Speech sound qualities, for example, have just been assumed to develop by simple imitation. In most accounts this is then assumed to be by acoustic matching, with the infant comparing his output to that of his caregiver. There are theoretical and empirical problems with both of these assumptions, and we present a computational model- Elija-that does not learn to pronounce speech sounds this way. Elija starts by exploring the sound making capabilities of his vocal apparatus. Then he uses the natural responses he gets from a caregiver to learn equivalence relations between his vocal actions and his caregiver's speech. We show that Elija progresses from a babbling stage to learning the names of objects. This demonstrates the viability of a non-imitative mechanism in learning to pronounce.

KLAIR: A virtual infant for spoken language acquisition research

Recent research into the acquisition of spoken language has stressed the importance of learning through embodied linguistic interaction with caregivers rather than through passive observation. However the necessity of interaction makes experimental work into the simulation of infant speech acquisition difficult because of the technical complexity of building real-time embodied systems. In this paper we present KLAIR: a software toolkit for building simulations of spoken language acquisition through interactions with a virtual infant. The main part of KLAIR is a sensori-motor server that supplies a client machine learning application with a virtual infant on screen that can see, hear and speak. By encapsulating the real-time complexities of audio and video processing within a server that will run on a modern PC, we hope that KLAIR will encourage and facilitate more experimental research into spoken language acquisition through interaction. Copyright © 2009 ISCA.

EARLY MOTHER-INFANT RELATIONSHIPS OF MACACA-THIBETANA AT MT-EMEI CHINA

Quantitative data on early mother-infant relationships in the Tibetan macaque was collected during the first 23 weeks of infant life in spring, 1987, at Mt. Emei, China. During the first week of life, infants spent 98.3% of their time in ventroventral contact with their mothers. This contact rapidly decreased to 33.8% by the 4th week and thereafter to 0.85% by the 23rd week. Nipple contact decreased relatively slowly from 89.7% to 62.9% within the first 4 weeks of infant life and to 19.8% by the 23rd week. Ventrolateral and ventrodorsal contact appeared by the 2nd week, mean-while, maternal restraining behavior appeared, and reached a peak by the 3rd week. The mother neither encouraged nor discouraged her infant's independence during 4-8th weeks. Maternal rejection of the infant was first observed when the infant was 11 weeks old and continued thereafter.

Male-infant-male interactions in Tibetan macaques

Event-sampling and scans were used for collecting data on male-infant-male triadic interactions, and their effects on member spacing respectively in a group of Macaca thibetana at Mt. Emei in 1989. The group was partially provisioned by human visitors in seasons other than winter, and could be observed closely. In addition, a stable linear male-hierarchy among five males existed for two years since the end of 1987, providing a good social condition for this topic. The triadic interactions were specific to the birth season, and recognized as three types being on a continuum functionally changing from passive ''agonistic buffering'' (4.8%) to active spatial cohesion, which resulted in a significant decline of intermale distances. Positive correlations were documented between the triad initiation rate and the number of females in consort with the males in the mating season (MS), and between the triad reception rate and the number of infants in proximity to the males in the MS when maternal care was significantly reduced. Thus the male's mating effort and kin/sexual selection may deeply be involved in the triad of this species. Considering that the two triad-species, M. sylvanus and M. thibetana, had different levels of paternity, but shared similar foraging conditions, and showed similar intensities of male-infant caretaking, the triad was very likely a byproduct of male-infant caretaking, which was probably shaped to compensate heavy maternal investment to young offspring in harsh conditions. Accordingly, the long-term arguments about the triad in M. sylvanus can be united to a model of the way in which ''male-infant caretaking'' hypothesis works ultimately, and ''regulating social relations'' hypothesis does proximately.

Hydrogen-Bonding Recognition-Induced Color Change of Gold Nanoparticles for Visual Detection of Melamine in Raw Milk and Infant Formula

The color change induced by triple hydrogen-bonding recognition between melamine and a cyanuric acid derivative grafted on the surface of gold nanoparticles can be used for reliable detection of melamine. Since such a color change can be readily seen by the naked eye, the method enables on-site and real-time detection of melamine in raw milk and infant formula even at a concentration as low as 2.5 ppb without the aid of any advanced instruments.