Orally mediated sources of calming in 1- to 3-day-old human infants.

In this study, the calming effects of sucrose in 1–3-day-olds was evaluated. Sucrose (0.5 ml, 14% weight/volume) reduced crying relative to water. Infants who received 0.2, 0.6, or 1.0 ml of sucrose cried much less than infants who sucked a pacifier for 2.6, 10, or 14 min. Sucrose infused through a pacifier reduced crying more effectively than did water through a pacifier. These differences support the idea of two separate functional calming systems in human newborns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensorimotor and motivational determinants of hand-mouth coordination in 1-3-day-old human infants.

Hand-mouth coordination was studied in 1–3-day-old human infants by delivering 0.2 ml of sterile 12% sucrose solution intraorally once every 2 min. Sucrose was extraordinarily calming and caused sustained hand-in-mouth contact. The calm state persisted well beyond sucrose termination. Hand-in-mouth behavior, however, stopped upon sucrose termination, demonstrating stimulus control over this integrated behavior. In subsequent studies we demonstrated that hand-in-mouth behavior was not attributable to calming per se. Moreover, hand activity could be prevented by placing a pacifier in the mouth. This demonstrates that the behavior was under intraoral somesthetic control and was not necessarily the expression of a motor pattern triggered by the sweet taste. These findings are interpreted within the contexts of sucrose (a) calming through an endogenous opioid system and (b) activating suckling-feeding mechanisms, causing the expression of integrated hand, mouth, and head motor patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lymphocyte phenotyping in infants: maturation of lymphocyte subpopulations and the effects of HIV infection

Oxygen administration is one of the most important therapeutic interventions for a child with severe acute lower respiratory tract infection (ALRI). Inexpensive and efficient methods of oxygen administration are highly desirable in hospitals in developing countries. The objectives of this study were to compare the frequency and nature of complications when nasopharyngeal catheters or nasal prongs are used to deliver oxygen. One hundred and twenty-one children between the ages of 2 weeks and 5 years with hypoxia due to ALRI were randomized to receive oxygen via a catheter (61 children) or via nasal prongs (60 children). The two groups were similar in terms of diagnoses, clinical severity, oxygen saturation on admission and case fatality rates. There was no difference in the incidence of hypoxaemic episodes between the two groups. The oxygen flow rates required on the day of admission for adequate oxygenation (SaO2 > 90%) ranged from 0.8 litres per minute to 1.2 litres per minute. The required oxygen flow rate decreased during the course of treatment. Mucus production was more of a problem in the catheter group, and nasal blockage, intolerance of the method of oxygen administration and nursing effort were generally higher amongst the catheter group, but none of these differences was significant. Ulceration or bleeding of the nose was significantly more common in the catheter group (19.7% vs 6.7%, p < 0.05). Abdominal distension and nasal perforation were not seen in either group. This study suggests that nasal prongs are safer, more comfortable and require less nursing expertise than nasopharyngeal catheters for administration of oxygen to children.     

Heart rate variability in 1-day-old infants born at 4330 m altitude

BACKGROUND: Rates of low-birth-weight (LBW) infants are similar between Latina and white women, an epidemiologic paradox. However, few studies have analyzed the relationship between ethnicity, Latino subgroup, confounding variables, and LBW. METHODS: We analyzed 395070 singleton livebirths to Latina and non-Latina white women in California during 1992. Multivariate logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the risks due to Latino ethnicity and Latino subgroup for very LBW (VLBW, 500-1499 g) and moderately LBW (MLBW, 1500-2499 g) outcomes. RESULTS: Latina and white women had similar unadjusted rates of VLBW (0.7% vs. 0.6%) and MLBW infants (3.7% vs. 3.4%). After adjusting for maternal age, education, birthplace, marital status, parity, tobacco use, use of prenatal care, infant sex, and gestational age, there was no difference in the odds of VLBW infants between Latina and white women (OR, 0.93 [95% CI, 0.81-1.071). Latina women had minimally elevated odds of MLBW infants (OR, 1.06 [95% CI, 1.01-1.11]) compared with white women. By Latino subgroup, there was no difference in the adjusted odds of VLBW infants among Central and South American, Cuban, Mexican, Puerto Rican, and white women. The adjusted odds of MLBW infants were elevated among Central and South American (OR, 1.14 [95% CI, 1.05-1.25]) and Puerto Rican women (OR, 1.41 [95% CI, 1.12-1.78]), relative to white women. CONCLUSIONS: The epidemiologic paradox of LBW in Latinos is valid. New conceptual models are needed to identify Latina women who are at risk for adverse pregnancy outcomes.     

Lymphocyte markers in newborn infants

Purified peripheral blood lymphocytes from 20 newborn infants and 12 adults have been studied for the presence of surface markers. Adults and infants did not differ in the percentage of sheep RBC-binding cells (means 58-65%) or in Ig-bearing cells measured by the mixed antiglobulin reaction (means 7.2-11.6%). However, newborn infants had a significantly lower percentage of lymphocytes binding Fc of IgG (mean 10.4%) as compared to adults (mean 17.2%). No overall correlation between plasma Ig levels and Ig-bearing lymphocytes was found but a single infant with increased plasma IgA also showed the highest level of Ig-bearing lymphocytes among all infants.     

Lymphocyte subpopulations in the mammary gland of the goat

Mammary glands of pregnant, lactating and resting goats were studied by immunohistochemistry for lymphocyte subpopulations using a panel of monoclonal antibodies. All T lymphocyte subpopulations that may have a role in the immune response, CD2+, CD4+, CD8+ and gamma delta T cells and subsets, were present in the mammary gland and were noted to increase in number progressively during pregnancy, decrease significantly during lactation, and then moderately increase during the resting period. CD4+ cells, the predominant cell type in the mammary gland, were located mainly in the connective tissue, whereas CD2+, CD8+ and TcR1-N24+ cells were predominant in the intraepithelial areas. TcR1-N6+ cells were detected almost exclusively during pregnancy, being localized mainly in the connective tissue. Their proportion decreased markedly following parturition. Very few WC1-N3+ and -N4+ cells were detected in the mammary gland. It is suggested that the majority of gamma delta T lymphocytes in the mammary gland of the goat are CD2+ CD8+ WCl-, a distinctive subset from that of the WCl+ subset in peripheral blood.     

Differential effects of sucrose, fructose, glucose, and lactose on crying in 1- to 3-day-old human infants: Qualitative and quantitative considerations.

Assessed the potency of different sugars as calming agents in human infants. Five 0.1-ml aliquots of 0.51M sucrose, fructose, glucose, or lactose were presented to 1- to 3-day-old infants who were crying spontaneously. Sucrose and fructose were equally effective calming agents, glucose slightly less so. Lactose, the milk sugar, was not at all effective and did not reduce crying any more than did water. In fact, some babies cried more when given lactose. A 2nd experiment established quantitative, dose-response functions for sucrose as a calming agent: 0.17M, 0.42M, and 0.51M sucrose reduced crying equally effectively. Moreover, crying reduction was not differentially affected by the volume of ingested sucrose, because 0.2 ml of 0.34M sucrose was as effective as 0.6 or 1.0 ml of 0.34M sucrose. Results suggest that sucrose calms in a stepwise manner with a flat suprathreshold function and that the calming basis of milk must be sought in components other than its sugar. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How do 4-day-old infants categorize multisyllabic utterances?

Three experiments, using the high-amplitude sucking procedure, tested whether 4-day-old infants discriminate multisyllabic utterances on the basis of number of syllables or number of phonemes. Exp 1 showed that infants discriminate 2 large sets of phonetically variable utterances composed of 2- vs 3-CV (consonant–vowel) syllables. Exp 2 was run to assess whether infants discriminated the 2 sets on the basis of duration differences between the 2- and 3-CV stimuli. Results indicate that reducing the duration differences does not affect infants' discrimination. Finally, Exp 3 investigated whether infants discriminate 4- vs 6-phoneme bisyllabic utterances. The results provide no evidence that infants are sensitive to such a change in number of phonemic constituents. Although not decisive, these results appear to be congruent with the hypothesis that infants perceptually structure complex speech inputs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lymphocyte activation gene-3 (LAG-3) expression and IFN-gamma production are variably coregulated in different human T lymphocyte subpopulations

We evaluated the relationship between cytokine profile and the expression of the lymphocyte activation gene-3 (LAG-3) in both T cell clones and polyclonal T cell lines; LAG-3 is a CD4-like protein whose expression is reportedly restricted to Th1/0 cells and dependent upon IFN-gamma. We found that, while LAG-3 was expressed only by CD4+ T cell clones producing IFN-gamma, most CD8+ clones producing IL-4 but not IFN-gamma (i.e., with a T cytotoxic-2-like profile) were LAG-3+. The intensity of LAG-3 expression by CD8+ clones correlated with the amount of released IFN-gamma, suggesting that this cytokine is not required for expression but rather for the up-regulation of LAG-3. Flow cytometric analyses of polyclonal T cell lines confirmed that LAG-3 could be expressed by both CD4+ and CD8+ cells that did not contain cytoplasmic IFN-gamma. In these cell lines, large proportions of CD4+ and CD8+ cells coexpressed LAG-3 and CD30, a putative marker of Th2-like cells. Overall, our data do not support the earlier suggestion that LAG-3 and CD30 are selective markers of T cells with type-1 and type-2 cytokine profiles, respectively.     

Free amino acids and peptides in the muscles of 1- and 2-day-old cadavers

High-voltage electrophoresis and the analytic procedure combination of high-voltage electrophoresis--paper chromatography were used for the analysis of protein-free extracts of muscle tissue in one-- to two--day old corpses. The protein-free extracts from both types of tissue specimen were found to contain also peptides in addition to free amino acids. The amino acids composition of isolated fractions is not mutually comparable. There were also differences as regards peptides. In the two--day corpse a new peptide appeared in the acid part and disappeared in the weak base part. The changes suggest that not only proteolysis but also peptidolysis are in progress on the second post-mortem day.     

Self-stimulation in 7- and 10-day-old rats.

It has been shown that the infant rat exhibits learned behaviors characteristic of the adult. With a modified self-stimulation paradigm, the present study explored whether 7- and 10-day-old Long-Evans rat pups could learn a discriminated operant to obtain direct electrical stimulation in neural sites that support self-stimulation in adults. By nudging 1 of 2 response manipulanda, at 2 ages (7 and 10 days) and temperatures (22 and 35°C), Ss self-stimulated with electrodes implanted in a variety of forebrain sites, including the prefrontal cortex, bed nucleus of the stria terminalis, medial nucleus of the amygdala, and the medial forebrain bundle. The only temperature-sensitive site might be the nucleus accumbens, which was positive only at the higher temperature in 10-day-olds. Results indicate that several forebrain sites demonstrate rewarding properties of stimulation in the preweanling rat pup. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for infant-directed singing in 2-day-old hearing infants of deaf parents.

L. J. Trainor (1996) reported preferences for infant-directed versus infant-absent singing in English in 4–7-month-old hearing infants of English-speaking hearing parents. In this experiment, the author tested preferences for infant-directed singing versus adult-directed singing in 15 two-day-old hearing infants of deaf parents for a Japanese and an English play song. Using a modified visual-fixation-based auditory-preference procedure, the author found that infants looked longer at a visual stimulus when looking produced infant-directed singing as opposed to adult-directed singing. These results suggest that infants prefer infant-directed singing over adult-directed singing and that the preference is present from birth and is not dependent on any specific prenatal or postnatal experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lymphocyte subpopulations of workers in a plant producing plastic materials (preliminary study)

Lymphocyte subpopulations were studied in 31 men working in a plant producing plastic materials in relation with control groups of similar age and smoking habit. 8 workers (group A) were exposed to solvents (mainly methylethylketone and dimethylformamide), 8 men (group B) to dust containing particles of calcium carbonate, polyvinylchloride, phtalates, unsaturated oils, paraffin wax, iron oxides, titanium bioxides, barium, zinc and lead and 15 men (group C), working in the same department as group B, were studied after a period of 16 months during which lead chromate was employed in the preparation of colors. The lymphocyte subpopulations were normal in group A, while in B there was a significant increase of HLA-DR + cells (monocytes, B and activated T lymphocytes). In group C, T helper/inducer lymphocytes (mainly CD4(+)-CD45RO- "virgin" lymphocytes), CD19+ B lymphocytes, CD3-HLADR+ and CD3-CD25+ (activated B lymphocytes and monocytes) were significantly reduced without changes of serum IgM, IgG and IgA. Highly significant correlation was found between B lymphocytes (reduced in the workers about 40%) and CD4(+)-CD45R0+ "memory" lymphocytes (reduced about 20%). Moreover, blood lead (correlated with urinary chromium) showed a highly significant negative correlation with the B lymphocytes. This study demonstrates that combined exposure to toxic agents produces specific modifications in the lymphocyte subsets without changes in immunoglobulins and confirms the results of previous researches showing that the exposure to lead or chromate induces reduction of lymphocytes in the peripheral blood.     

Smooth pursuit in 1- to 4-month-old human infants

The ability of human infants < or = 4 months of age to pursue objects smoothly with their eyes was assessed by presenting small target spots moving with hold-ramp-hold trajectories at ramp velocities of 4-32 deg/sec. Infants as young as 1 month old followed such target motions with a combination of smooth-pursuit and saccadic eye movements interrupted occasionally by periods when the eyes remained stationary. The slowest targets produced variable performance, but targets moving 8-32 deg/sec produced consistent pursuit behavior, even in the youngest infants. By the fourth month, eye-movement latency decreased and smooth-pursuit gain and the percentage of smooth pursuit per trial increased for all target velocities, though these measures had not yet reached adult levels.     

Arterial oxygen saturation profiles in healthy preterm infants

AIM: To construct a reference range of SpO2 values in healthy preterm infants using a simple data logging device. METHODS: Thirty three healthy preterm infants were monitored for a continuous period of 4 hours at rest using an Ohmeda Biox 3700 E Pulse Oximeter and an electronic data logger (Rustrack Ranger). Stored data were downloaded and saved as individual files on a personal computer. RESULTS: The study group median and 5th and 95th percentiles were used to construct a cumulative frequency curve of time against SpO2 value, representing the normal reference range of SpO2 profiles in healthy preterm infants. CONCLUSION: Comparison of an infant's SpO2 profile against this curve may be more helpful in guiding supplemental oxygen treatment in that individual than a figure for a mean SPO2 and its standard deviation.     

Mechanisms of gastroesophageal reflux in healthy premature infants

A seroprevalence study for poliomyelitis was carried out on a sample of sera from a serum bank used for a vitamin A study. Vaccination coverage was satisfactory (80% or more) in five of nine provinces, although a prevalence of antibody to polio of 80% or more was found in all provinces. Serologic immunity (i.e., the prevalence of neutralizing antibodies) exceeded vaccination coverage, suggesting secondary spread of vaccine virus. However, whether or not water was supplied through a piped system was not associated with secondary spread of vaccine virus to nonvaccinated children. Seroprevalence studies are a valuable adjunct to acute flaccid paralysis surveillance, which is the standard surveillance instrument for the poliomyelitis eradication initiative. The use of available and suitable serum banks for seroprevalence investigations is a relatively cheap monitoring option that can yield very valuable information for the eradication initiative.     

Event-specific expectations of 2- and 3-month-old infants.

The Visual Expectation Paradigm (M. M. Haith et al, 1988) was modified to assess the role that picture content plays in the spatiotemporal expectations of 2- and 3-mo-old infants. Infants watched pictures of 700-msec duration that appeared in left–right alternation with a 1,000-msec interstimulus interval. The same picture occurred repeatedly on one side, in alternation with an unpredictable picture on the other side. Across 3 studies, the unchanging picture, rather than engendering habituation, produced higher levels of anticipation and speeded reactions. Thus, infants used the stable picture-content information to facilitate formation of expectations about when and where pictures would appear. Although 2-mo-olds were consistently slower than 3-mo-olds, their reaction times (RTs) benefited more from predictability than did the RTs of older infants. The percentage of anticipatory fixations did not differ between the 2 age groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object permanence in 3?- and 4?-month-old infants.

These experiments tested object permanence in 3-12- and 4-12-month-old infants. The method used in the experiments was similar to that used by Baillargeon, Spelke, and Wasserman (1985). The infants were habituated to a solid screen that rotated back and forth through a 180° arc, in the manner of a drawbridge. Following habituation, a box was placed behind the screen and the infants were shown two test events. In one (possible event), the screen rotated until it reached the occluded box; in the other (impossible event), the screen rotated through a full 180° arc, as though the box were no longer behind it. The 4-12-month-olds, and the 3-12-month-olds who were fast habituators, looked reliably longer at the impossible than at the possible event, suggesting that they understood that (a) the box continued to exist after it was occluded by the screen and (b) the screen could not rotate through the space occupied by the occluded box. Control experiments conducted without the box supported this interpretation. The results of these experiments call into serious question Piaget's (1954) claims about the age at which object permanence emerges and about the processes responsible for its emergence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Plasma cortisol responses after intramuscular corticotropin 1-24 in healthy men

Intravenous infusion of corticotropin 1-24 (ACTH 1-24) followed by a plasma cortisol measurement after 60 minutes of less than 20 microg/dL indicates clinically important glucocorticoid deficiency. In this study, we evaluated the morning plasma cortisol response to an intramuscular (IM) injection of ACTH 1-24 (250 microg) in 64 healthy men. Plasma cortisol increased significantly 30 and 60 minutes after IM ACTH 1-24 (P < .0001). In most subjects, a maximal response was obtained at 60 minutes. The cortisol response correlated positively with the morning basal cortisol concentration. The lowest cortisol peak and the lowest increment observed after IM ACTH 1-24 were, respectively, 12.6 and 3.5 microg/dL after 30 minutes and 16.3 and 5.3 microg/dL after 60 minutes. We conclude that a plasma cortisol level less than 16.0 microg/dL 60 minutes after IM ACTH 1-24 can be used as an index of glucocorticoid deficiency.