Modelling consultation rates in infancy: influence of maternal and infant characteristics, feeding type and consultation history

BACKGROUND

Severity of illness, sociodemographic factors, and breastfeeding have been identified as predictors of consultation rates in infants, and prescriptions for antibiotics have been found to increase future consultation rates in older children. The Baby Check trial (1996-1998) provided detailed information about consultations for 935 babies during their first 6 months.

AIMS

To investigate potential predictors of consultation rates in babies.

DESIGN OF STUDY

A 6-month cohort study of newborn babies originally enrolled into a randomised controlled trial. Maternal and infant characteristics were collected from hospital discharge records. Primary care consultation data for each baby were collected by case note review.

SETTING

Thirteen general practices in Glasgow.

METHOD

Multilevel models were used to analyse the number of consultations for each baby during its first 26 weeks, dependent upon the baby's age, the calendar month, maternal and infant characteristics, and previous consultations.

RESULTS

The strongest predictors of consultation rates were previous consultations, particularly during the preceding week. Breastfed babies and those with older mothers consulted less often. A multilevel model was better than a fixed effects model, with considerable variation in consultation rates between babies.

CONCLUSION

Infants' consultation rates over time can be analysed using multilevel models, if details of primary care consultations are available. These models can incorporate the effects of fixed variables and those that change during the follow-up period. Our findings add to previous research linking breastfeeding with reduced morbidity in infancy, and for that reason breastfeeding should continue to be promoted in primary care.

A comparison of the sleep-wake patterns of cosleeping and solitary-sleeping infants

This study examined whether 3-15, month-old cosleeping infants displayed differences in time spent in active versus quiet sleep, and in the number/duration of nighttime awakenings when compared with solitary-sleeping infants; and also whether they spent the majority of the night sleeping face-to-face, as previously reported. Nine cosleeping and nine solitary-sleeping infants were matched on age, gender, ethnicity, maternal age, and family SES. Video recordings of nighttime sleep yielded percentage of time in active sleep, quiet sleep, and awake, number of wakenings, and the percentage of time cosleeping infants and mothers spent face-to-face. Across age, cosleeping infants had more awakenings per night mean 5.8(1.50) versus 3.2(1.95); t = 3.16, p = .006). The percent of the nighttime spent awake did not differ between groups, suggesting that cosleeping infants had shorter awakenings. Cosleeping infants spent 40% of the night face-to-face with their mothers.

Too much or too little: neonatal ocular misalignment frequency can predict later abnormality

BACKGROUND

214 orthoptists' infants have been followed for up to 15 years, relating neonatal misalignment (NMs) and first convergence onset to later childhood ocular abnormalities. NMs are shown in a companion paper to reflect the onset of first convergence, but if frequent or absent may predict a higher risk of refractive error and esodeviation.

METHODS

In a prospective postal survey, orthoptist mothers observed their own infants during the first months of life and regularly reported ocular behaviour and alignment, visual development, and any subsequent ocular abnormalities.

RESULTS

Later strabismus and refractive error were less common in infants who showed NMs occasionally compared with those who never or frequently did. There was a significant linear trend for fewer ocular abnormalities to be found in children with more frequent NMs (p<0.001). Hypermetropes were later to show first convergence than emmetropes or myopes (p = 0.006)

CONCLUSIONS

NMs usually reflect an emerging and normally developing vergence system. This study suggests that delayed onset of convergence (and lack of NMs) is associated with later defects, especially hyperopia. Possible causal relations are discussed.

Neonatal ocular misalignments reflect vergence development but rarely become esotropia

BACKGROUND

214 orthoptists' infants have been followed for up to 15 years, relating neonatal misalignment (NMs) behaviour to onset of convergence and 20 Delta base out prism response, and also to later childhood ocular abnormalities.

METHODS

In a prospective postal survey, orthoptist mothers observed their own infants during the first months of life and regularly reported ocular behaviour and alignment, visual development, and any subsequent ocular abnormalities.

RESULTS

Results confirm previously reported characteristics of NMs. Infants who were misaligned more frequently were misaligned for longer periods (p <0.01) and were later to achieve constant alignment (p <0.001) but were earlier to attempt first convergence (p = 0.03). Maximum NM frequency was usually found at or before the onset of first convergence (p = 0.0002).

CONCLUSIONS

NMs occur in the first 2 months of life and usually reflect a normally developing vergence system. They appear to represent early attempts at convergence to near targets. Emerging infantile esotropia is indistinguishable from frequent NMs before 2 months.

Population pharmacokinetics of intramuscular gentamicin administered to young infants with suspected severe sepsis in Kenya

AIMS

To determine the population pharmacokinetics of intramuscular (i.m.) gentamicin in African infants with suspected severe sepsis.

METHODS

Samples were withdrawn 1 h after a single i.m. injection of 8 mg x kg(-1) gentamicin and the next morning prior to any further dosing. Concentration-time data were analysed with the population pharmacokinetic package NONMEM. Data were fitted using a one-compartment model with a log-normal model for interindividual variability and an additive residual error model. The influence of a range of clinical characteristics was tested on the pharmacokinetics of intramuscular gentamicin and the effect of incorporating interindividual variability on bioavailability was examined.

RESULTS

The data set comprised 107 patients and 203 concentrations. Peak concentrations ranged from 3.0 mg x L(-1) to 19.8 mg x L(-1) (median 10.6 mg x L(-1)) and 'next day' samples from 0.3 mg x L(-1) to 6.2 mg x L(-1). The best models were clearance/bioavailability (CL) (L x h(-1)) = 0.0913 x weight (kg) x (age (days) + 1)/11)0.130 and volume of distribution/bioavailability (V) = 2.02 x (1 + 0.277 x (weight -3)). Therefore, an infant with the median weight of 3 kg and age 10 days would have a predicted CL of 0.274 L x h(-1) and V of 2.02 L. Interindividual variability in CL was 40% and in V was 42%. This model required a term for covariance between CL and V. When variability in bioavailability was introduced as an alternative model, interindividual variability in CL was 22%, in V 18% and in relative bioavailability 36%.

CONCLUSIONS

Intramuscular administration of 8 mg x kg(-1) gentamicin daily to infants gives mean 1 h peak concentration of 10.6 mg x L(-1) and a trough concentration of less than 2 mg x L(-1). Wide variability in the peak concentration may reflect variable absorption rate or bioavailability.

Use of benzimidazoles in children younger than 24 months for the treatment of soil-transmitted helminthiasis

Considerable experience and limited quantitative evidence indicate that infections with the soil-transmitted helminths Ascaris lumbricoides and Trichuris trichiura usually start to become established in children aged 12 months and older. Since children living in countries where the infections are endemic are at risk of morbidity, even those as young as 12 months may need to be considered for inclusion in public health programmes designed to reduce morbidity by means of regular anthelminthic chemotherapy. This situation raises the question as to whether such young children should be given anthelminthic drugs. Systems for the absorption, distribution, metabolism and elimination of drugs do not fully develop until children are in their second year of life. Current knowledge, however, reveals that the incidence of side effects linked to benzimidazole drugs in young children is likely to be the same as in older children. Accordingly, we conclude that albendazole and mebendazole may be used to treat children as young as 12 months if local circumstances show that relief from ascariasis and trichuriasis is justified.

Early postnatal development of sensory gating

Sensory gating represents the nervous system's ability to inhibit responding to irrelevant environmental stimuli. In order to characterize the early development of acoustic sensory gating, suppression of auditory evoked potential component P1 (i.e. P50) in response to paired clicks was measured during REM sleep in healthy infants (1-4 months) that were without genetic risk for disrupted sensory gating function (i.e. having a relative with schizophrenia). As a group, the subjects exhibited significant response suppression. A correlation between increasing age and stronger response suppression was uncovered, even within this restricted age range. Parallel changes in sleep physiology could not be ruled out as the explanation for this change. Nevertheless, these results demonstrate that the neural circuits underlying sensory gating are functional very early in postnatal development.

Human immunoglobulin M memory B cells controlling Streptococcus pneumoniae infections are generated in the spleen

Splenectomized and asplenic patients have a high incidence of infections by encapsulated bacteria and do not respond to polysaccharide vaccines. To understand whether the absence of the spleen is associated with a defined B cell defect, we analyzed B cell subsets in the peripheral blood. We found that a population of B cells known as immunoglobulin (Ig)M memory is lacking in patients without spleen. The absence of IgM memory B cells correlates with an impaired immune response to encapsulated bacteria not only in splenectomized patients, but also in individuals with an intact spleen. We show that the physiological and transient predisposition to pneumococcal infections of young children (0-2 yr) is associated with the lack of circulating IgM memory B cells and of serum antipolysaccharide IgM. We also demonstrate that IgM memory B cells are undetectable in a fraction of patients with common variable immunodeficiency, who have recurrent and invasive infections by encapsulated bacteria. IgM memory B cells, therefore, require the spleen for their generation and/or survival and are responsible for the protection against encapsulated bacteria.

Emmetropisation following preterm birth

BACKGROUND/AIMS

Even in the absence of retinopathy of prematurity (ROP), premature birth signals increased risk for abnormal refractive development. The present study examined the relation between clinical risk factors and refractive development among preterm infants without ROP.

METHODS

Cycloplegic refraction was measured at birth, term, 6, 12, and 48 months corrected age in a cohort of 59 preterm infants. Detailed perinatal history and cranial ultrasound data were collected. 40 full term (plus or minus 2 weeks) subjects were tested at birth, 6, and 12 months old.

RESULTS

Myopia and anisometropia were associated with prematurity (p<0.05). More variation in astigmatic axis was found among preterm infants (p<0.05) and a trend for more astigmatism (p<0.1). Emmetropisation occurred in the preterm infants so that at term age they did not differ from the fullterm group in astigmatism or anisometropia. However, preterm infants remained more myopic (less hyperopic) than the fullterm group at term (p<0.05) and those infants born <1500 g remained more anisometropic than their peers until 6 months (p<0.05). Infants with abnormal cranial ultrasound were at risk for higher hyperopia (p<0.05). Other clinical risk factors were not associated with differences in refractive development. At 4 years of age 19% of the preterm group had clinically significant refractive errors.

CONCLUSION

Preterm infants without ROP had high rates of refractive error. The early emmetropisation process differed from that of the fullterm group but neither clinical risk factors nor measures of early refractive error were predictive of refractive outcome at 4 years.

Aberrant composition of gut microbiota of allergic infants: a target of bifidobacterial therapy at weaning?

BACKGROUND

Recent data have outlined a relationship between the composition of the intestinal microflora and allergic inflammation, and demonstrated the competence of probiotics in downregulation of such inflammation.

AIMS

Our aims were to characterise the relationship between gut microbes and the extent of allergic sensitisation and to assess whether the efficacy of bifidobacterial supplementation in the treatment of allergy could relate to modulation of the intestinal microbiota.

METHODS

This randomised study included 21 infants with early onset atopic eczema of whom eight were intolerant (highly sensitised group (HSG)) and 13 tolerant (sensitised group (SG)) to extensively hydrolysed whey formula (EHF). In the SG, six were weaned to EHF without (placebo group (PG)) and seven to EHF with Bifidobacterium lactis Bb-12 supplementation (bifidobacteria treated group (BbG)). The faecal microflora of infants in the HSG was analysed only before weaning whereas in the SG the faecal microflora was analysed both before and after weaning.

RESULTS

Infants in the HSG had greater numbers of lactobacilli/enterococci than those in the SG. Serum total IgE concentration correlated directly with Escherichia coli counts in all infants and with bacteroides counts in the HSG, indicating that the presence of these bacteria is associated with the extent of atopic sensitisation. The effect of supplementation was characterised as a decrease in the numbers of Escherichia coli and protection against an increase in bacteroides numbers during weaning.

CONCLUSIONS

These data indicate that bifidobacterial supplementation appears to modify the gut microbiota in a manner that may alleviate allergic inflammation. Further studies are needed to confirm this conclusion.

Suppression of autologous peripheral blood mononuclear cell proliferation by alveolar macrophages from young infants

Maintenance of lung homeostasis involves a complex interaction between T lymphocytes and alveolar macrophages (AM), in which AM suppress pulmonary T cell proliferation to antigenic stimuli. To assess whether AM-mediated suppression is attenuated in healthy young infants, AM and peripheral blood mononuclear cells (PBMC) were sampled prior to elective surgery. Children were divided into <4 months of age (Group I) and >4 months (Group II). Autologous PBMC and AM were co-cultured in vitro with phytohaemaglutinin (PHA) at AM : PBMC ratios ranging from 2:1 to 1 : 5. Methyl-tritiated thymidine was added after 48 h and uptake determined at 72 h. Percentage suppression or enhancement of PBMC proliferation by AM was determined relative to proliferation of PBMC with PHA. To determine the role of soluble factors of suppression, cell-free supernatants from paediatric AM and PBMC co-cultures were added to PHA-stimulated adult PBMC. The median age was 3 months for Group I (n = 9) and 7 years 2 months (n = 13) for Group II. Percentage suppression of PBMC proliferation was attenuated in Group I (versus Group II) at AM : PBMC ratios of 2:1 (median 78 versus 92, P< 0 x 05) and 1 : 1 (45 versus 87, P< 0 x 01). Cell-free supernatants from Groups I and II suppressed proliferation of adult PBMC, but there was no difference in suppression between the age groups. We conclude that suppression of autologous PHA-stimulated PBMC proliferation by AM is attenuated in young infants, and this immaturity is not explained by reduced release of soluble factors.

The importance of rapid auditory processing abilities to early language development: evidence from converging methodologies

The ability to process two or more rapidly presented, successive, auditory stimuli is believed to underlie successful language acquisition. Likewise, deficits in rapid auditory processing of both verbal and nonverbal stimuli are characteristic of individuals with developmental language disorders such as Specific Language Impairment. Auditory processing abilities are well developed in infancy, and thus such deficits should be detectable in infants. In the studies presented here, converging methodologies are used to examine such abilities in infants with and without a family history of language disorder. Behavioral measures, including assessments of infant information processing, and an EEG/event-related potential (ERP) paradigm are used concurrently. Results suggest that rapid auditory processing skills differ as a function of family history and are predictive of later language outcome. Further, these paradigms may prove to be sensitive tools for identifying children with poor processing skills in infancy and thus at a higher risk for developing a language disorder.

Protein binding predictions in infants

Plasma binding protein levels are lower in the newborn than in the adult and gradually increase with age. At birth, human serum albumin (HSA) concentrations are close to adult levels (75%-80%), while alpha 1-acid glycoprotein (AAG) is initially half the adult concentration. As a result, the extent of drug binding to HSA is closer to that of the adult than are those drugs bound largely to AAG. A model that incorporates the fraction unbound in adults and the ratio of the binding protein concentration between infants and adults successfully predicted the fraction unbound in infants and children.

Decline of CD3-positive T-cell counts by 6 months of age is associated with rapid disease progression in HIV-1--infected infants

Because HIV-1 infected infants with rapid progression (RP) of disease might benefit from early and intense antiretroviral therapy, the identification of predictive factors of RP becomes extremely important. Currently, the best predictive factors of RP in HIV-1 infected children are HIV-1 RNA levels and CD4-positive T-cell counts. A decrease in CD3-positive T-cell count has been identified as a predictive factor of AIDS development in HIV-1 infected adults. Our objective was to evaluate decreased number of CD3-positive T-cells as a predictive factor of RP in infants. Peripheral blood lymphocytes from HIV-1 infected infants (up to 6 months of age) were analyzed for an association of lymphocyte subsets with RP, which was defined as the occurrence of AIDS or death before 18 months of age. In infants with RP (n = 32), CD3-positive T-cell counts were 3093 cells/microL at <1 month of age, 3092 cells/microL at 1 to 3 months, and 2062 cells/microL at 3 to 6 months. Non-RP infants (n = 49) maintained their CD3-positive T-cells counts at approximately 4000 cells/microL for at least 6 months of life. CD3-positive and CD4-positive T-cell counts were significantly associated with RP. Our results suggest that a decreased CD3-positive T-cell count may be used to predict RP in HIV-1 infected infants (RR = 2.16, P =.001).

Gender-related plasma levels of progesterone, interleukin-8 and interleukin-10 during and after cardiopulmonary bypass in infants and children

BACKGROUND

It is known that proinflammatory and anti-inflammatory cytokines are released during and after cardiopulmonary bypass (CPB) in infants and children. Sex steroids are known to have immunomodulatory functions, and release of the anti-inflammatory cytokine IL-10 is stimulated by progesterone in vitro. The purpose of the present study was to investigate the plasma levels of progesterone, IL-8 (proinflammatory cytokine) and IL-10, and to relate them to sex and postoperative morbidity.

METHOD

Eighteen infants and children (eight female) undergoing CPB were prospectively studied. Plasma levels of progesterone, IL-8 and IL-10 were determined before and 10 min after the start of CPB, and immediately after CPB; and 6 h, 24 h, 3 days and 7 days postoperatively. Organ dysfunction was identified on the basis of arbitrarily defined criteria.

RESULTS

After CPB, all patients showed significant increases in plasma levels of progesterone, IL-8 and IL-10. Plasma levels of IL-10 were significantly higher in female patients, except for during the immediate postoperative period. According to the criteria used, six out of 10 male patients, but none of the female patients developed multiple organ dysfunction (MOD).

CONCLUSION

The present study shows that CPB induces a significant and marked increase in plasma levels of progesterone in infants and children. Studies of administration of progesterone-blocking substances to male and female animals may help to elucidate the roles of sex and progesterone in the setting of CBP.

Adverse outcome of infants with metastatic neuroblastoma, MYCN amplification and/or bone lesions: results of the French society of pediatric oncology

To assess the relevance of MYCN amplification and bone lesions in stage 4 neuroblastoma (NB) in infants aged <1 year, 51 infants with stage 4 NB were enrolled. Three groups of patients were defined according to the type of metastases and the resectability of the primary tumour. Group I comprised 21 infants with radiologically detectable bone lesions, Group II 22 patients with an unresectable primary tumour and Group III eight patients with only metaiodobenzylguanidine (MIBG) skeletal uptake. MYCN oncogene content was assayed in 47/51 tumours and found to be amplified in 17 (37%). The 5-year event-free survival (EFS) rate of these 51 infants was 64.1% (+/- 7.1%). In a univariate analysis, bone lesions, MYCN amplification, urinary vanillylmandelic/homovanillic acid ratio and serum ferritin levels adversely influenced outcome. In the multivariate analysis, radiologically detectable bone lesions were the most powerful unfavourable prognostic indicator: the EFS rate was 27.2% for these infants compared to 90% for infants without bone lesions (P<0.0001). Our data emphasize the poor prognosis of infants affected by stage 4 NB with bone lesions, especially when associated with MYCN amplification. Given the poor results in this group whatever the treatment, new therapeutic approaches need to be investigated in the future.

Femoral vein size in newborns and infants: preliminary investigation

BACKGROUND

The femoral vein is an important site for central venous access in newborns and infants. The objectives of this study are to determine whether age or weight can be used clinically to predict the size of the femoral vein in newborns and infants, and to compare the size of the vein in each individual in both the supine and reverse Trendelenburg positions.

RESULTS

Analysis was done in 24 euvolemic individuals, each studied in both the supine and reverse Trendelenburg positions. Twelve of these individuals were newborns and 12 were infants. We used two-factor analysis of variance to explore differences between groups and multiple linear regression analysis to estimate the strength of the relationship between variables. In the infant group, there was a correlation between femoral vein diameter and weight. There was no correlation between weight and vessel size in newborns. In both the newborn and infant groups, vessel diameter increased with subjects in the reverse Trendelenburg position (P < 0.01).

CONCLUSION

Weight is predictive of femoral vein diameter in infants, but not in newborns. In infants, weight might serve as a more sensitive index for estimating size of the femoral vein in order to determine accurately the size of intravascular catheter appropriate for cannulation. The diameter of the femoral vein increases in the reverse Trendelenburg position compared with that in the supine position in both newborns and infants. A large prospective study is required to validate these findings.

Population pharmacokinetics of enterally administered cisapride in young infants with gastro-oesophageal reflux disease

AIMS

To investigate the pharmacokinetics of enterally administered cisapride suspension in young infants being treated for gastro-oesophageal reflux disease.

METHODS

Plasma cisapride concentrations in 49 subjects (weight: 825-5010 g; n=108 samples, median two per patient; concentration: 14.8-170 ng ml-1 ) were fitted to a one-compartment model with first-order absorption and elimination in the NONMEM program using a logarithmic transformation of the observed and predicted concentrations. Fitting was achieved using the first order conditional estimation (FOCE) method with interaction between the interpatient and intrapatient variabilities. The interpatient variance of clearance (CL/F ) and volume of distribution (V /F ) and their covariance were estimated using an exponential error model. Intrapatient (residual) variance was estimated using an additive model.

RESULTS

The clearance of cisapride was shown to be linearly related to current body weight, slope: 0.538. The typical population values of CL/F, V /F and Ka (absorption rate constant) were 0.538 l h-1 kg-1, 21.9 l, and 2.58 h-1, respectively. The population coefficients of variation (CV%) for CL/F and V/F were 34.4% and 84.3%, respectively. The squared coefficient of correlation between random effects for CL/F and V /F was 0.45. The intrapatient variance was 0.15. V /F and Ka were not influenced significantly by any patient characteristic.

CONCLUSIONS

Cisapride pharmacokinetics in infants with reflux disease were satisfactorily described by a one-compartment model. Current weight should be taken into account when calculating maintenance cisapride doses in these infants.

An approach for dose finding of drugs in infants: sedation by midazolam studied using the continual reassessment method

AIMS

No drug has been demonstrated to provide simultaneously appropriate sedation, safety and lack of disturbance of the measured parameters during cardiac catheterization in infants. The objective of this study was to estimate the dose of midazolam, administered rectally, that would provide a 90% probability of adequate sedation in infants during cardiac catheterization. A sedation score > or =4 (six-point scale) 30 to 60 min after dosing was rated as a success.

METHODS

A double-blind, continual reassessment method using a Bayesian approach has been used. Sixteen infants were administered a single midazolam dose, within a 0.1 to 0.6 mg kg(-1) dose range.

RESULTS

Consecutive failures led to allocation of the highest dose to 15 out of 16 patients. The final estimated probability of failure of the 0.6 mg kg(-1) dose was 81% (95% CI: 78.5 to 84%). The time to reach a score > or =4 was longer than expected and the median duration-time at score > or =4 was shorter (15 min) than expected.

CONCLUSIONS

Delayed absorption and low rectal bioavailability may explain these data. Higher doses or different routes of administration may lead to the expected sedation, but the safety of doses higher than 0.6 mg kg(-1) administered rectally has not been evaluated. The therapeutic strategy for sedation of this category of infants in the hospital has now been changed based on the present results in that rectal midazolam has been abandoned in this indication.

[Epidemiology of community-acquired pneumonia in children. Current data]

Viruses, particularly syncitial respiratory virus, are the main aetiology of community-acquired lower respiratory tract infections in infants, while bacterial agents are more frequently responsible in children older than 3 years. Antimicrobial therapy must take into account the development of reduced susceptibility of penicillin to strains of Streptoccocus pneumoniae and Haemophilus influenzae with beta-lactamase, and high frequency of Mycoplasma pneumoniae and Chlamydia pneumoniae infections. Although the mortality rate has remained low in France, the morbidity appeared to increase in recent years.

Age Changes in Interlimb Coupling and the Development of Bimanual Coordination

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni- versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 3 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as they anticipate mirror manipulations of the object less. The frequency of bimanual reaching increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.

Deferred Imitation Across Changes in Context and Object: Memory and Generalization in 14-Month-Old Infants

The influence of changes in context and object characteristics on deferred imitation was assessed in 14-month-old infants. In Experiment 1, infants in the imitation group saw an adult demonstrate target acts on miniature objects in an unusual context (an orange polka-dot tent). When later presented with larger objects in a normal laboratory room, these infants performed significantly more target acts than did controls. In Experiment 2, three groups of infants were tested. Infants in an imitation(no change) group saw an adult demonstrate target acts and were subsequently tested in the same room using the same objects as the adult. Infants in the imitation (context + object size & color change) group followed the same procedure, but both the context and two salient featural characteristics of the objects (size and color) were changed between encoding and the recall test of deferred imitation. Control infants did not see the target demonstrations. Results showed that the combined changes in context and object features led to a significant decrease in imitative performance. Nonetheless, in comparison to the controls, infants exhibited significant recall as indexed by deferred imitation. The results show that imitation generalizes across changes in object size, object color, and test context. The implications for theories of memory and representational development are discussed.

Weight gain in captive chimpanzee infants: Comparisons by sex, rearing, and colony

Weight gain has been monitored for 13 years in a mixed longitudinal study of captive chimpanzee growth and development. This report presents results of a comparative analysis of weight relative to age in 175 animals during the first 24 months in four sex/rearing groups (hand-reared females, hand-reared males, mother-reared females, and mother-reared males) from three colonies with different physical, nutritional, and social environments (Primate Foundation of Arizona, University of Texas M.D. Anderson Cancer Center Department of Veterinary Resources, Bastrop, TX, and White Sands Research Center, Alamagordo, NM). The Lowess method is used to generate fits of weight vs. age for each group and colony, with which individual animals at these and other colonies may be compared for assessment of developmental status. Comparisons of the curves, using the jackknife approach, show that there are significant differences between the curves, indicating that rearing and environmental parameters may be factors in weight gain rate and must be considered in such an assessment. Rearing effects may be the dominant of these factors in weight gain. © 1996 Wiley-Liss, Inc.

ACTH does not control neonatal seizures induced by administration of exogenous corticotropin-releasing hormone

ACTH has been used extensively for treatment of massive infantile spasms (MIS) and other intractable seizures. The mechanisms by which ACTH exerts anticonvulsant effects are unknown. ACTH is a neuropeptide with both endocrine and neuromodulatory properties; its efficacy against MIS could derive from intrinsic anticonvulsant properties or from hormonal effects, either directly or through glucocorticoids. We tested ACTH activity against exogenous corticotropin-releasing hormone (CRH)-induced seizures in the infant rat model. CRH was administered into the cerebral ventricles of 85 infant rats aged 5-13 days. ACTH was used either 20-60 min before CRH administration or "chronically" (pretreatment with four doses of ACTH every 6 h, before CRH administration). In a separate group of rat pups, we measured plasma corticosterone to ascertain ACTH availability. Administration of CRH, an age-specific endogenous convulsant, resulted in a prolonged series of seizures after 2- to 55-min latency. There was no difference in latency between controls (9.5 +/- 1.2 min) and ACTH-treated rats (12.4 +/- 2.8 min for combined acute and chronic groups). CRH-induced seizure duration (88.2 +/- 9 vs. 74.7 +/- 9.4 min) and severity of seizures was also unchanged by ACTH treatment. ACTH reached the circulation and caused significant increase in plasma glucocorticoids. ACTH does not block the convulsant action of exogenous CRH in infant rats. An alternative mechanism for the anticonvulsant effect of ACTH may be suppression of synthesis and secretion of an endogenous convulsant, i.e., CRH.

Stereoselective disposition of ibuprofen enantiomers in infants

The pharmacokinetics of the enantiomers of ibuprofen were investigated after oral administration of a single 7.6 +/- 0.3 mg kg-1 dose of the racemate in 11 infants. Mean (+/- s.d.) half-lives were 1.6 +/- 0.5 h for S(+) and 1.5 +/- 0.5 h for R(-) and mean (+/- s.d.) AUC values were 31.5 +/- 14.3 mg l-1 h for S(+) and 36.6 +/- 13.8 mg l-1 h for R(-). Since plasma concentrations of the active S(+)-isomer were lower than those reported in adults, a higher dosage might be required in infants.

Office screening for urinary tract infections in infancy

A retrospective report of the experience of nine years of simplified office screening for infantile urinary tract infection (UTI) is compared with the more invasive and stringent methodology widely considered necessary. Urine samples were obtained from 1313 infants of two years or less. In 27 of these infants UTI was diagnosed and the data analysed from 24 cases. Nine infants were completely asymptomatic, while the rest had non-specific symptoms. Radiological investigations were carried out in all the infants with UTI. Urine samples were obtained without any specific precleansing of the perineum, and the criteria for diagnosing UTI were two consecutive positive cultures. The results were statistically similar to studies in which there was pre-cleansing, and in which the criteria were three consecutive positive cultures.

Respiratory emergencies in infants and young children

Emergencies involving the respiratory tract are not uncommonly encountered in infants and young children. The spectrum of disorders causing respiratory distress varies from self-limited disorders such as bronchiolitis to potentially life-threatening conditions such as acute epiglottitis. This article outlines the clinical manifestations of some of the common respiratory emergencies presenting in infants (beyond the neonatal period) and young children, as well as strategies for management.

Controversies on feeding babies: a critical review

THERE ARE SIX CHIEF CONTROVERSIES RELATING TO INFANT NUTRITION: breast- vs. bottle feeding; the age to start solids; the need for supplemental iron, fluorides, or vitamins; sterilization of formulas; food allergies; and the relationship of infant feeding to subsequent coronary heart disease. This article discusses these controversies and reviews the evidence on both sides of each question.

Imitation, Objects, Tools, and the Rudiments of Language in Human Ontogeny

Human beings are imitative generalists. We can immediately imitate a wide range of behaviors with great facility, whether they be vocal maneuvers, body postures, or actions on objects. The ontogeny of this skill has been an enduring question in developmental psychology. Classical theory holds that the ability to imitate facial gestures is a milestone that is passed at about one year. Before this time infants are thought to lack the perceptual-cognitive sophistication necessary to match a gesture they can see with one they cannot see themselves perform. A second developmental milestone is the capacity for deferred imitation, i.e. imitation of an absent model. This is said to emerge at about 18 months, in close synchrony with other higher-order activities such as object permanence and tool use, as part of a general cognitive shift from a purely sensory-motor level of functioning to one that allows language. Research suggests that the imitative capacity of young infants has been underestimated. Human infants are capable of imitating facial gestures at birth, with infants less than one day old manifesting this skill. Moreover recent experiments have established deferred imitation well before the predicted age of 18 months. Studies discussed here show that 9-month-olds can duplicate acts after a delay of 24 hours, and that 14-month-olds can retain and duplicate as many as five actions over a 1-week delay. These new findings re-raise questions about the relation between nonverbal cognitive development and language development: What aspects, if any, of these two domains are linked? A hypothesis is delineated that predicts certain very specific relations between particular cognitive and semantic achievements during the one-word stage, and data are reported supporting this hypothesis. Specifically, relations are reported between: (a) the development of object permanence and the use of words encoding disappearance, (b) means-ends understanding (as manifest in tool use) and words encoding success and failure, and (c) categorization behavior and the onset of the naming explosion. This research on human ontogeny suggests close and highly specific links between aspects of early language and thought.

The use of skinfold measurements to judge obesity during the early phase of Prader-Labhart-Willi syndrome

We report the first prospective longitudinal study of dietary intake, weight, height, and skinfold measurements during the early phase of four Prader-Labhart-Willi syndrome (PLWS) individuals (two males and two females). Although caloric intake ranged from 80 to 90 percent of recommended daily allowance during our study of the four PLWS infants, obesity still occurred. Our findings suggest that the onset of obesity in PLWS individuals occurs earlier than previously thought in spite of reduced caloric intake. The infants in our study reached the obese range judged by skinfold measurements greater than the 85th centile at an early age and before they were considered heavy based on weight for height criterion. We propose that skinfold measurements should be obtained on all individuals with PLWS and obesity judged by this criterion.

Otitis media in "water babies"

To examine the clinical impression that the incidence of otitis media in infant swimmers ("water babies") is higher than that in non-swimmers, we reviewed the records and interviewed the parents of 186 children under the age of four and one-half years seen in a suburban family practice. Sixty-five% (46/71) of swimmers as compared to 50% (58/115) of non-swimmers had been diagnosed as having at least one episode of otitis media. Although this difference was not statistically significant (p=0.055), this pilot study encouraged us to pursue further the possible association between otitis media and early-childhood swimming classes.

Audiometry in young children

The author of this article reviews various techniques in the auditory assessment of infants and young children. The success of these tests depends on the overall functioning of the child, and not on chronological age alone. Any significant deviation from the normal auditory behaviour should raise suspicion of possible auditory impairment. Diagnostic audiology involves more than mere testing of the peripheral auditory mechanism in isolation. It necessitates investigation of possible neurological impairment, mental retardation, emotional disturbance, and hearing loss. Early diagnosis is facilitiated by the battery of auditory tests comprising behavioural, impedance audiometry and auditory brain-stem response audiometry. Interpretation of test findings must be carefully assessed in the light of other pertinent information.

Management of diarrhea in infants and children

Diarrhea affecting infants and children is an important primary-care problem. Most winter infections are caused by rotavirus, but newer viral, bacterial and protozoan pathogens have been discovered. Fluid and electrolyte therapy is the mainstay of therapy. Antiemetic, antibiotic and antidiarrheal medications can usually be avoided. Commercial clear fluid products have been reformulated to allow effective rehydration and maintenance of hydration, thus avoiding hospitalization or use of intravenous therapy. Patients are quickly advanced to nutrient feedings using breast milk or formula. There is strong evidence that Canadian physicians should use these protocols which work as well in North America as in the countries of the developing world.

A Critical Look at the Family Physician's Role in Preventing Childhood Injuries

Childhood injuries stand as the most common causes of death among Canadian children. Physician advice and advocacy of appropriate legislation, parent education and legislative action could reduce this toll. There is a role for family physicians in the important process of providing a safer environment for our children.

Common dermatoses of infancy

Within the pediatric population of their practices, family physicians frequently encounter infants with skin rashes. This article discusses several of the more common rashes of infancy: atopic dermatitis, cradle cap, diaper dermatitis and miliaria. Etiology, clinical picture and possible approaches to treatment are presented.

Restrain infants, secure kids: a community program to teach parents to buckle up their children

In 1981, the Council on Road Trauma developed an education program for the Hamilton-Wentworth area of Ontario, aimed at groups responsible for patient care and/or education. The program's purpose was to increase use of infants' car restraints. A questionnaire was developed to collect data from women hospitalized at the birth of a baby. The women were questioned about their education on car restraints and whether they had a car seat for the new baby. Of the 723 who completed questionnaires, 90% reported having a car seat. Eighty-three percent of those who attended prenatal classes received information about car safety from their prenatal teachers. Only 18% of the mothers reported that physicians discussed car safety. Judging from the survey results, all prenatal education programs, physicians providing prenatal and pediatric care, and public health nurses should give parents information about all aspects of infant safety.

Epidemiology of respiratory syncytial virus infection among infants and children in Chicago

From January 1, 1967 to December 1971, the temporal pattern of respiratory syncytial virus infection was investigated in infants and children younger than 18 months hospitalized for acute lower respiratory tract disease. Of 4696 infants and children with acute lower respiratory tract disease admitted to the Cook County Hospital, 2530 were tested for virus infection by virus isolation or serologic procedures or both. Overall, respiratory syncytial virus infections were detected in 12% and parainfluenza 3 virus in 10.8% of individuals tested. Other respiratory viruses were less commonly identified. Respiratory syncytial virus epidemics occurred annually and were temporally synchronous with the peak periods of respiratory disease admissions. Only during epidemics of respiratory syncytial virus did admission for respiratory tract disease usually reach 40 patients or more weekly. The peak months of respiratory syncytial virus epidemics were December 1966, January 1968, February-March 1969, April 1970 and January 1971. Epidemics lasted about 17 weeks. No similar annual epidemic pattern was seen with the other myxoviruses.