Human infants’ response

Later in intra-uterine life, the human infant is susceptible to early chemical prompting, but again the affector route is not known with certainty. Neonatal discrimination in favour of familiar (maternal) amniotic fluid is demonstrable, suggesting that the foetus already has active chemosensory capacities (Schaal, 1998). Smell and taste are operative in the near full-term foetus since it shows detection of about 120 mg/day maternal intake of anethole (as anise condiments) within a few days before parturition this exposure induced subsequent preferential responses by babies to anethole (Schaal et ai, 2000). The human neonate is not likely to have its organ as a fully functioning chemosensor,... 

Much as in other mammals, human females concentrate in their mammary regions features potentially related with infant-directed communication. The potential semiochemical significance of the human breast will be examined here in terms of 1) morphology and secretory activity of areolar skin glands 2) infant responses when exposed to the effluvium of their mother s breast and areolae, and to the odour of related secretions 3) volatile compounds present in pure areolar secretions as compared with those of milk 4) relations of maternal areolar gland endowment to adaptive outcomes in the infant and the mother. 

AG secretion increased inspiratory amplitude in the infants more than all stimuli, but human milk. Thus, AG cues appear to carry the same general behavioural impact as milk, indicated by the intensification of respiration, but they have distinctively higher appetitive impact than milk and sebum, as attested by oro-facial responses. Interestingly, the mode of feeding, and hence the rate of previous exposure to breast-related stimuli, did not affect the infant responses to the odour of AG secretion. 

Human breast milk is the best nutrient for preterm infants and is often delivered via gavage feeding methods before the baby s sucking skills mature. Because sufficient quantities of the mother s fresh breast milk may not be available, milk may be frozen for later consumption or be provided by donor mothers. To protect against the risk of disease transmission, donor milk is usually pasteurized. In the present study, we assessed preterm infants responses to the odours of different categories of milk that are routinely available in neonatal intensive care nurseries. 

Several studies have been conducted on calcium-fat interactions in human infants (64-70). Low synthesis of bile salts and low pancreatic lipase activity may be responsible for poorer fat utilization in infants than in adults (63,71). Fat from infant formulas may be lower than that from human milk because of the lack of a bile-stimulated lipase in the former (72). In infants, fat absorption tends to decrease with increase in fatty acid length, with lower degree of saturation, and with increase of total fat (3). Triglyceride structure may also influence fat absorption in the infant and, thus, indirectly, might also affect calcium absorption in the infant. 

Phytoestrogens can cause infertility in some animals and thus concerns have been raised over their consumption by human infants. The isoflavones found in a subterranean clover species (in Western Australia) have been identified as the agents responsible for an infertility... 

Breton ME, Quinn GE, Schueller AW. Development of electroretinogram and rod phototransduction response in human infants. Invest Ophthalmol Vis Sci 1995 36 1588-1602. 

In water, ammonia volatilizes to the atmosphere, is transformed to other nitrogenous compounds, or may be bound to materials in the water. Volatilization is highly pH-dependent, and can also depend on other factors such as temperature, wind speed, and atmospheric concentration. Transformation of ammonia in water occurs by the microbial processes of nitrification and denitrification. Nitrification yields nitrate and nitrite anions the former species can be responsible for methemoglobinemia in human infants if the contaminated water is ingested. Removal of ammonia from water can also occur by adsorption to sediments or to suspended organic material. 

However, as illustrated in Fig. 19, the magnitude of brain AChE inhibition is clearly age- and dose-dependent, and although dramatically inhibited in neonatal rats (lOmg/kg response), the adults appear to be refractory to any AChE inhibition at these same dose levels. Although these simulations illustrate the ability to scale age-dependent changes within a species, the different time scales between development in neonatal animahs and human infants create uncertainty in extrapolation across species (Ginsberg ct uL, 2004). 

Somatostatin (SRIF) inhibition of TRH-stimulated TSH secretion has been demonstrated in the neonatal rat using SR IF antiserum as early as 3 days of age (0.4 of thyroid development) (19). However no effect on basal TSH levels was observed during the first 60 days of age (19). Exogenous SR IF inhibits the TSH response to TRH In neonatal lambs (31). Finally, dopamine receptor blockade in neonatal rats had no effect on serum TSH levels during the first 6 weeks of life and no effect at birth in human infants (32,33). 

Diamond A. 1990. The development and neural bases of memory functions as indexed by the AB and delayed response tasks in human infants and infant monkeys. Ann N Y Acad Set 608 267—309. 

Secondary immunodeficiencies (9) are much more common than primary ones and frequently occur as a result of immaturity of the immune system in premature infants, immunosuppressive therapy, or surgery and trauma. Illnesses, particularly when prolonged and serious, have been associated with secondary immunodeficiencies, some of which may be reversible. Acquked immune deficiency syndrome (AIDS) (10—12) may be considered a secondary immunodeficiency disease caused by the human immunodeficiency vimses HIV-1 or HIV-2. Hitherto unknown, the disease began to spread in the United States during the latter part of the 1970s. The agent responsible for this infection has been isolated and identified as a retrovims. 

Anderson, P.W., Pichichero, M.E., Stein, E.C., Porcelli, S., Betts, R.F., Connuck, D.M., Korones, D., Insel, R.A., Zahradnik, J.M., and Eby, R. (1989) Effect of oligosaccharide chain length, exposed terminal group, and hapten loading on the antibody response of human adults and infants to vaccines consisting of Haemophilus influenzae type b capsular antigen uniterminally coupled to the diphtheria protein CRMI97./. Immunol. 142, 2464-2468. 

In the same way as volatiles from the whole breast, odorants carried in human colostrum/milk are arousing and attractive to newborns (Mizuno, Mizuno, Shino-hara and Noda 2004 Marlier and Schaal 2005). Interestingly, neonatal responsiveness to these milk cues does not seem to depend on breastfeeding experience as term-born infants exclusively fed formula (Marlier and Schaal 2005), and premature infants (Bingham et al. 2003), react to them in the same way as regularly breast-fed infants. 

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