Growth of rhesus monkeys during the first 54 months of life

As part of a study of the long-term effects of environmental conditions on the health and development of non-human primates, the growth of 60 rhesus monkeys (Macaca mulatta, 34 males and 26 females) was determined longitudinally with biweekly or triweekly measurements of eight body dimensions from one to 54 months of age. Our data showed similar growth to previous studies and provide additional data defining normal rhesus monkey growth under more precisely defined living conditions than were reported in previously published studies on this species.     

Ultrasonographic assessment of kidney dimensions in first six months of life

The kidney growth in children is not linear. The aim of this study was to define normal dimensions of kidneys in healthy infants during the first six months of life. A prospective ultrasonographic screening of 1870 kidneys in 935 healthy full-termed infants (476 males, 459 females) was done throughout a 5-year period. Measured kidneys were divided into six age groups according to gender and side. In the first three months of life males had both kidneys longer than same-age females (p < 0.05). In the next three-month-period the difference between sexes was not significant (p > 0.05). Left kidneys were longer than right kidneys in both sexes in the first six months of life (p < 0.01). Four nomograms with normal values of kidney lengths, according to age, sex and side were done in newborns and infants in the first 6-months of life.     

A descriptive analysis of gut microbiota composition in differentially reared infant rhesus monkeys (Macaca mulatta) across the first 6 months of life

The gastrointestinal microbiome is recognized as a critical component in host immune function, physiology, and behavior. Early life experiences that alter diet and social contact also influence these outcomes. Despite the growing number of studies in this area, no studies to date have examined the contribution of early life experiences on the gut microbiome in infants across development. Such studies are important for understanding the biological and environmental factors that contribute to optimal gut microbial colonization and subsequent health. We studied infant rhesus monkeys (Macaca mulatta) across the first 6 months of life that were pseudo‐randomly assigned to one of two different rearing conditions at birth: mother‐peer‐reared (MPR), in which infants were reared in social groups with many other adults and peers and nursed on their mothers, or nursery‐reared (NR), in which infants were reared by human caregivers, fed formula, and given daily social contact with peers. We analyzed the microbiome from rectal swabs (total N = 97; MPR = 43, NR = 54) taken on the day of birth and at postnatal Days 14, 30, 90, and 180 using 16S rRNA gene sequencing. Bacterial composition differences were evident as early as 14 days, with MPR infants exhibiting a lower abundance of Bifidobacterium and a higher abundance of Bacteroides than NR infants. The most marked differences were observed at 90 days, when Bifidobacterium, Lactobacillus, Streptococcus, Bacteroides, Clostridium, and Prevotella differed across rearing groups. By Day 180, no differences in the relative abundances of the bacteria of interest were observed. These novel findings in developing primate neonates indicate that the early social environment as well as diet influence gut microbiota composition very early in life. These results also lay the groundwork for mechanistic studies examining the effects of early experiences on gut microbiota across development with the ultimate goal of understanding the clinical significance of developmental changes.     

The laboratory diagnosis of cytomegalovirus infection in infants in the first months of life

The detection rate of IgM, specific to cytomegalovirus (CMV), in the umbilical blood was 2.0 +/- 1.8% in infants with antenatal complications in their medical history, 8.9 +/- 1.8% in hospitalized infants aged 7 days to 6 months; simultaneously, such IgM proved to be absent in healthy infants of the same age. The maximum primary detection rate of CMV-specific IgM in hospitalized infants was registered at the age of 1.5-4 months and the minimum detection rate, at the age of 6 months, as well as at the age of 1 month and younger. In sick infants aged 0-6 months CMV-specific IgM were detected, as a rule, for 2-4 weeks. 86% of infants with CMV-specific IgM detected in their blood were found to have cytomegaloviremia; in 80% of patients the virus was excreted with saliva and in 50% the virus was detected in blood plasma.     

Changes in infant segment inertias during the first three months of independent walking

Background

During infancy, rapid changes in physical growth affect the size and shape of the body segments. To understand the effects of growth on movement, it is first necessary to quantify rates of development during the acquisition of important motor milestones. The goal of this longitudinal study was to quantify the physical growth of infant body segments during the initial stages of independent walking.

Methods

Ten infants (N = 10) aged between 28 and 55 weeks at the beginning of the study were tested biweekly (every two weeks) for three months. A 13-segment mathematical model of the human body was used to estimate the inertial parameters of the infant body segments at each session. An analysis of variance was used to test for significant differences in segment masses between biweekly measures. Polynomial contrasts were used to test for linear trends in the growth data.

Results

Significant differences between biweekly measures of segment mass were found only for the head/neck (F(5,45) = 3.42, p < 0.05), upper trunk (F(5,45) = 4.04, p < 0.01), and lower trunk (F(5,45) = 3.49, p < 0.01). The lower trunk demonstrated a linear increase in mass (F(1,9) = 4.56, p < 0.05). However, the upper trunk demonstrated a quadratic trend in growth (F(1,9) = 9.13, p < 0.01), while the head/neck segment showed a cubic trend in growth (F(1,9) = 3.80, p < 0.05). Significant differences in axial segment masses were also found between subjects (F(9,45) = 5.92, p < 0.001).

Conclusion

Given that postural control proceeds in a cephalocaudal manner, the lower trunk segment would be brought under control last, in terms of the axial segments. Increases in the mass of this segment could constrain the system, thereby acting as a control parameter for the onset and development of motor patterns.

     

Plasma selenium in preterm and term infants during the first 12 months of life

The goal of the present study was to prospectively assess the plasma selenium (Se) concentrations of term and preterm infants during the first year of life in relation to gestational age and nutrition.

Blood specimens were collected from orally formula-fed preterm infants (gestational age < 32 weeks, birth weight < 1500 g): 1.) in hospital and 2.) corrected for gestational age parallel to healthy term breast and formula-fed infants at the ages of 1, 4 and 12 months. All infants were fed according to a standardized nutritional concept, solids and follow-up formula were introduced at the age of 4 months.

Plasma selenium in preterm infants in hospital was 11.7 (6.5–20.8) g/l and 11.6 (8.8–16.7) g/l at 4 weeks corrected for gestational age. At the age of 4 months plasma selenium was still significantly lower than in the other groups: Preterm infants: 17.1 (10.4–30.5) g/l; formula-fed term infants: 31.3 (24.3–47.5) g/l; breast-fed term infants: 45.6 (27.1–65.1) g/l). The levels of breast-fed infants were significantly higher than those of both formula-fed groups up until the introduction of solids.

Preterm infants had significantly low plasma selenium levels up until a postnatal age of at least 6 months. The levels were lower than those of term infants fed an identical unsupplemented infant formula during the first 4 months of life. These data support routine monitoring in hospital and selenium supplementation of preterm infants, preferably in hospital before discharge.     

Molybdenum supply of very low-birth-weight premature infants during the first months of life

This explorative study was performed to assess basic data on the Mo metabolism of premature infants. Premature (n=18, gestational age ≤32 wk, birth weight ≤1500 g) and healthy formula-fed term infants (n=14) were nourished and corrected for gestational age, identically. Plasma was collected at 3, 16, and 52 wk and 72 h balances were performed at 3 wk of age. In the premature infants, these investigations were preceded by two balance studies and an initial plasma collection. Increased Mo intake and low relative urinary excretion resulted in a retention of 4.4 (0.99–7.77) μg Mo/kg initially in premature infants (median, range). Parallel plasma concentrations were 5.5 (2.5–7.3) μg Mo/L, declining to 2.36 (0.73–3.87) μg Mo/L at 4 wk. Term infants rendered 1.49 (0.29–1.7) μg Mo/L (p<0.05), with no significant differences later. It was concluded that the supplementation of formulas for premature infants with Mo should be recinded until there is evidence for its necessity.     

Developmental trends in mother-infant interactions in Java macaques (Macaca fascicularis) during the first ten days of life

In this study on Java macaques themain characteristics of the mother-infant relationship during infants' first 10 days have been elaborated. Early mother and infant behaviour is described and early interactions between mothers and their young have been analyzed. Observations and trend analyses of early behaviours like ventro-ventral contact behaviour, being on nipple, and explorative behaviour, make it clear that Java macaque infants play an important role in the early development of mother-infant interactions. In contrast to the rhesus and the stumptailed infant, the young Java macaque appears to develop a great variety of behaviours in its first 10 days. Whereas the infant's behaviour gains in complexity and social initiative, the mother becomes increasingly more passive and self-oriented. Early mother-infant interaction can be characterized by mutual adjustment.     

Chemotherapy of Pseudomonas aeruginosa infections in children during the first three months of life]

The data on the efficacy of antibacterial drugs and their combinations in treatment of 150 three-month old infants with generalized infection due to Pseudomonas aeruginosa are presented. The clinical isolates of P. aeruginosa were found to be carriers of multiple drug resistance which markedly complicated the chemotherapy. Only combined antibacterial therapy of such infants proved to be rational. High activity of aminoglycosides, azlocillin and cefotaxime against P. aeruginosa and the synergistic action of their combinations observed in the patients permitted to recommend the use of combinations of the above drugs in the empirical chemotherapy.     

Pituitary-adrenocortical responses to the first dyadic encounters in male rhesus monkeys: effect of dominance relationship

Male rhesus monkeys unfamiliar with each other were paired in a cage, and blood samples were collected before and a few hours after pair formation. Adrenocorticotrophic hormone (ACTH) and cortisol levels in each blood sample were measured. Dominant-subordinate status was ascertained through two rank tests, the food competition test and the agonistic behavior test, which were performed immediately after pair formation. As a result, the dominance relationship was determined in seven pairs formed from five animals, and the differences in ACTH and cortisol values between the dominant and subordinate animal in these pairs were compared statistically. The day after the first encounter, a second encounter was conducted in randomly selected pairs of monkeys. In the first encounters, higher levels of both ACTH and cortisol were detected in dominant animals in comparison to subordinate animals. Changing the animal's partner altered the stress responses whenever the animal's dominant-subordinate status changed. The elevated levels of ACTH and cortisol in dominant animals disappeared on the day after the first encounter. In dominant animals, the pituitary-adrenocortical stress response reacts sharply to situational demands, whereas subordinate animals have a weaker response. This acute stress response is different from a chronic stress response. When the subordinate animal cannot escape, its hypothalamic-pituitary-adrenocortical axis appears to be suppressed.