Both beta(2)- and beta(1)-adrenergic receptors mediate hastened relaxation and phosphorylation of phospholamban and troponin I in ventricular myocardium of fallot infants, consistent with selective coupling of beta(2)-adrenergic receptors to G(s)-protein

Background-In adult human heart, both beta(1)- and beta(2)-adrenergic receptors mediate hastening of relaxation; however, it is unknown whether this also occurs in infant heart. We compared the effects of stimulation of beta(1)- and beta(2)-adrenergic receptors on relaxation and phosphorylation of phospholamban and troponin I in ventricle obtained from infants with tetralogy of Fallot. Methods and Results-Myocardium dissected from the right ventricular outflow tract of 27 infants (age range 2-1/2 to 35 months) with tetralogy of Fallot was set up to contract 60 times per minute. Selective stimulation of beta(1)-adrenergic receptors with (-)-norepinephrine (NE) and beta(2)-adrenergic receptors with (-)-epinephrine (EPI) evoked phosphorylation of phospholamban (at serine-16 and threonine-17) and troponin I and caused concentration-dependent increases in contractile force (-log EC50 [mol/L] NE 5.5+/-0.1, n=12; -EPI 5.6+/-0.1, n=13 patients), hastening of the time to reach peak force (-log EC50 [mol/L] NE 5.8+/--0.2; EPI 5.8+/-0.2) and 50% relaxation (-log EC50 [mol/L] NE 5.7+/-0.2: EPI 5.8+/-0.1), Ventricular membranes from Fallot infants, labeled with (-)-[I-125]-cyanopindolol, revealed a greater percentage of beta(1)- (71%) than beta(2)-adrenergic receptors (29%). Binding of (-)-epinephrine to beta(2)-receptors underwent greater GTP shifts than binding of (-)-norepinephrine to beta(1)-receptors. Conclusions-Despite their low density, beta(2)-adrenergic receptors are nearly as effective as beta(1)-adrenergic receptors of infant Fallot ventricle in enhancing contraction, relaxation, and phosphorylation of phospholamban and troponin I, consistent with selective coupling to G(s)-protein.

Association of Streptococcus mutans Infection and Oral Developmental Nodules in Pre-dentate Infants

Since dental caries may present soon after tooth eruption, we hypothesized that colonization of Streptococcus mutans can occur in the predentate stages. In this study, we examined S. mutans colonization and its association with oral developmental nodules (Bohn's nodules) in 60 pre-term and 128 full-term, three-month-old infants. Overall, S. mutans was cultured from 30% (56/188) of the infants, and oral developmental nodules were noted in 55% (103/188). Compared with the pre-term, full-term infants showed a higher prevalence of S. mutans (34% vs. 20%, p < 0.02) as well as developmental nodules (61% vs. 42%, p < 0.05). In both groups, S. mutans was positively associated with numbers of developmental nodules in a dose-response relationship (p < 0,001), and with maternal salivary levels of the bacteria (p = 0.03). The permanence of S. mutans infection was confirmed by repeat saliva sampling at 6 months of age. Our results thus showed that many infants have already acquired S. mutans at 3 months of age, prior to tooth eruption.

Oral Colonization of Streptococcus mutans in Six-month-old Predentate Infants

We hypothesize that S. mutans colonization occurs more frequently in pre-term children due to their relative immaturity. In this study of 172 predentate, six-month-old infants, we found that 50% of pre-term and 60% of full-term children harbored S. mutans. The colonization was confirmed by repeat sampling. Although there were minor differences, factors associated with S. mutans infection in pre-term and full-term infants were generally similar. In both groups, increased frequency of sugar was ranked the most important factor (p < 0.001), followed by breast-feeding (p < 0.001), and habits which allowed saliva transfer from mother to infant (p < 0.01). By contrast, non-colonization of S. mutans was associated with multiple courses of antibiotics (p < 0.001). Compared with pre-term children, there were higher percentages of full-term who had night feedings and consumed sugar during sleep times. Mothers with infected infants had S. mutans levels > 5 x 10(5) CFU/mL saliva (p < 0.001), poorer oral hygiene,, more periodontal disease, and lower socio-economic status (P < 0.02) and snacked frequently (p < 0.001), compared with mothers with non-infected infants.

Childhood neglect and cognitive development in extremely low birth weight infants: A prospective study

Objective. To examine the relationship between child maltreatment and cognitive development in extremely low birth weight infants, adjusting for perinatal and parental risk factors. Methods. A total of 352 infants with birth weight of

Immunoglobulins in saliva of preterm and full-term infants. A longitudinal study from 0-18 months of age

The aim of this longitudinal study was to determine salivary levels of total IgA, IgG and IgM in 84 preterm and 214 full-term infants, from birth to 18 months of age. Unstimulated whole saliva was collected from each infant at birth, and subsequently at 3-monthly intervals. Immunoglobulin levels were estimated using an ELISA technique. At birth, IgA was detected in 147/214 (69%) full-term infants but only 47/84 (56%) preterm infants (P