Development of the Transdermal Potential of Human Skin

Abstract

ABSTRACT. The development of the transdermal electrical potential (TDP) with postnatal age was studied in neonates born at gestational ages of 25 to 42 wk. The TDP of neonates born at less than 28 wk gestational age was of similar magnitude over the whole skin surface when measured in the first 5 d of life (mean value -5.4 mV; skin surface negative with respect to s.c. tissues). The TDP increased progressively with increasing gestational and postnatal age. The rate of increase of the TDP with postmenstrual age was not accelerated in neonates born prematurely. TDP values of infants born at term were lower than those of adults, but the sites of high and low TDP were similar in both term infants and adults. (Pediatr Res 29: 78-81, 1991) Abbreviations TDP, transdermal electrical potential An electrical potential difference exists across many epithelia. It results from the balance of active transport of ions across the epithelium and the permeability of the epithelium to the passive diffusion of ions along the electrochemical gradients produced by the active transport processes. The magnitude of the potential is dependent on the structure and function of the epithelium and may be altered in disease states, as in cystic fibrosis, where epithelial cells have decreased passive permeability to chloride ions. This causes decreased reabsorption of chloride from sweat, resulting in increased negativity of the transdermal potential and abnormally high sweat chloride concentration.In adult humans, the TDP is generated largely in the sweat glands. Its magnitude depends on the activity and density of distribution of the glands, the hydration of the epidermis, and the integrity and permeability of the living cell layers of the epidermis (1). All of these factors are altered in premature infants.We studied the evolution of the TDP in premature infants compared to that of term infants and of adults. SUBJECTS A N D METHODSThe TDP was measured in three groups of subjects over a 3-month period. from the dorsum of the hand, the flexor and extensor aspects of the forearm, the chest and the back (when the baby was able to be turned safely), the dorsum of the foot, and the middle of the plantar surface of the foot.The results were grouped into 5-d periods of postnatal age. When more than one set of observations was collected during one time period from one individual, only the result nearest the median day of the time period was considered. This resulted in analysis of 86 sets of observations from 49 premature infants.All infants required i.v. cannulas for their medical management. Thirty-three (67.3%) of the 49 infants had respiratory distress syndrome.Group 2. Nine sets of observations from nine term infants aged 0-5 d were analyzed. Each set of observations consisted of TDP measurements from 30 skin sites, which were obtained while the infants were asleep.All of the infants were asymptomatic at the time of observation but were receiving antibiotics through peripheral i.v. cannulas for suspected perinatal infection. No pathogens we...

Effective use of transdermal drug delivery in children

“…The appearance and cellular differentiation of the eccrine system is the same in term and pre-term infants; however most >36 weeks GA infants can sweat in response to environmental stimulus on their first day of life whereas pre-term (< 36 weeks GA) cannot [5,7]. Transdermal electrical potential measurements also suggest that sweat glands are immature in infants of less than 24 wk GA, skin resistance increases with GA and appears to mature around 36 weeks GA [52]. Sebaceous glands, which provide most of the lipids for the vernix caseosa, are visible by the 18 th week of gestation but remain hypertrophic for some weeks after birth as a result of maternal hormone exposure [5,7,10].…”

Εφίδρωση Και Υπεριδρωσία Παλαμών

“…Μία επιπλέον ένδειξη πως ένα σημαντικό μέρος της εκδήλωσης της εφίδρωσης των π-π μπορεί να είναι αποτέλεσμα λειτουργικής μάθησης προέρχεται από το γεγονός πως τα νεογέννητα δεν ιδρώνουν "συγκινησιακά" μέχρι το δεύτερο μήνα ή και αργότερα, αν και ενεργοί ιδρωτοποιοί αδένες υπάρχουν στην παλάμη τους από την πρώτη μέρα της ζωής τους (Verbow and Baxter 1974, Harpin and Rutter 1982, Mackay et al 1991.…”