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The objective of our study was to develop a small 1.5-T MRI system for neonatal imaging that can be installed in the neonatal ICU (NICU) and to evaluate its performance in 15 neonates.A 1.5-T MR system designed for orthopedic use was adapted for neonatal imaging. Modifications included raising and leveling the magnet, construction of a patient table, and integration of imaging electronics from a high-performance adult-sized scanner. The system was used to perform MR examinations of the brain, abdomen, and chest in 15 medically stable neonates using standard clinical protocols. The scanning time was limited to 60 minutes. The MR examinations were performed without administering sedation to the patients. ECG, heart rate, oxygen saturation, and temperature were monitored continuously throughout the examination. The images were evaluated by two pediatric radiologists for overall study quality, motion artifact, spatial resolution, signal-to-noise ratio, and contrast.All 15 neonates were successfully imaged without sedation. No adverse MRI-related events were noted. In total, 19 brain and seven abdominal examinations were performed. Six chest and two cardiac examinations were also obtained. Gross (versus physiologic) subject motion proved to be the most influential factor in determining overall study and image quality. High-quality diagnostic images were obtained at each anatomic location.The customized neonatal MRI system provides state-of-the-art MRI capabilities in the NICU.

Neonatal skin hydration decreases rapidly postnatally and then increases, indicating adaptive changes in stratum corneum water handling properties. Transition from high to low humidity at birth may initiate filaggrin proteolysis to free amino acids. Neonatal skin with vernix caseosa retained is more hydrated than skin with vernix removed. This study examines the potential roles of free amino acids and vernix in postnatal adaptation of infant stratum corneum in vivo. Specifically, the ontogeny of free amino acid generation in neonatal stratum corneum and the role of vernix caseosa in postnatal adaptation were examined using high performance liquid chromatography. Free amino acids were quantified for infant skin samples collected at (i) birth and 1 month and (ii) birth and 24 hours after vernix caseosa retention or removal and compared to neonatal foreskin, vernix caseosa, and adult stratum corneum using t-tests, analysis of variance, or univariate procedures. Free amino acids were extremely low at birth, significantly higher 1 month later but lower than in adults. Vernix caseosa retention led to significantly higher free amino acids 24 hours after birth compared to infants with vernix caseosa removed, and it paralleled the higher stratum corneum hydration of vernix caseosa-retained skin. Vernix caseosa contained free amino acids, with glutamic acid and histidine levels higher than in infants. Free amino acids in vernix caseosa-retained skin appear to originate from vernix caseosa. Free amino acids were lower in neonatal foreskin than adult forearm stratum corneum. Arginine was higher than citrulline at birth, but levels were comparable in older infants. The free amino acid increase at 1 month may be initiated by the humidity transition at birth and supports results in animals. The findings have implications for infant skin care practices.

To characterize vernix caseosa in newborn infants with respect to factors that influence vernix distribution on the skin surface, vernix effects on thermal stability, skin hydration, acid mantle development, and vernix antioxidant properties. Vernix distribution was determined for 430 infants. Thermal stability was assessed in parallel groups following vernix retention (n=66) and removal (n=64). The effects of vernix retention on skin hydration, pH, erythema, and dryness/scaling were determined. Samples were analyzed for vitamin E before and after UV exposure. Vernix distribution depended upon gestational age, delivery mode, gender, race, and meconium exposure. Retention had no effect on axillary temperatures. Skin hydration was significantly higher for vernix-retained skin. Skin pH and erythema were significantly lower with retention. Vitamin E levels were decreased by ultraviolet radiation. Vernix is a naturally occurring barrier cream with multiple salubrious effects, which support its retention on the skin surface at birth.

Background/Aims: Premature infants lack the vernix caseosa, have an incompetent stratum corneum (SC) barrier and are predisposed to infection. Use of topical agents to improve barrier function has had mixed outcomes. The aim was to determine the effect of vernix versus common barrier creams on the rate and quality of the epidermal barrier repair following controlled wounding. Methods: Minor wounds were created with (1) laser ablation in the minipig and (2) tape stripping of mother’s volar skin as a model for premature skin. Native vernix was applied to the mother’s tape-stripped skin. Treatments were no occlusion (NO), vernix and a petrolatum-based cream (PBC) in the pig, and NO, vernix, PBC, an oil-in-water cream (OWC), a semipermeable film (SP) and full occlusion (FO) in adults. Results: Outcomes for both trials were barrier recovery and skin hydration (moisture accumulation rate, MAT), initial hydration, erythema and dryness in adults. Vernix and PBC produced greater barrier repair than NO in the pig. SP produced greater recovery than NO and FO in adults. Vernix yielded greater recovery than FO and was similar to PBC, OWC and NO. Vernix had a directionally higher MAT than OWC and directionally higher initial hydration than NO. Conclusions: The findings suggest that vernix-based topical creams would be effective for the treatment of epidermal wounds and show promise to augment SC repair and maturation in infants.

The skin forms a critical structural boundary and a perceptual interface for the organism, yet the definition "healthy skin" is surprisingly difficult to describe. The present study's goal was to generate a technical definition of healthy infant skin by quantifying specific biophysical parameters before and after bathing in infants and correlating such parameters to a perceptual maternal evaluation. Fifty-two healthy infants, 3-6 months old, were evaluated before and after freshwater bathing. Diapered skin had a higher transepidermal water loss (TEWL), surface hydration, moisture accumulation rate (MAT), and friction than nondiapered skin before the bath (p < 0.01). Bathing dramatically altered the biophysical properties at both skin sites, with decreased MAT and lower friction, indicating a drier skin surface (p < 0.01). Visual redness and dryness decreased after bathing (p < 0.01). Blinded grading of optical images showed a significant preference for the skin after bathing (p < 0.01). This study provides the first quantitative technical definition of healthy infant skin with positive correlation to perceptual assessment by independent observers (mothers). The findings support the hypothesis that water binding properties of the stratum corneum are altered by occlusion (diapering) and that bathing introduces acute changes in stratum corneum water interactions, leading to a drier skin surface and a preferred skin appearance.

pp. 13–22 Natural moisturizing factor (NMF) is essential for appropriate stratum corneum hydration, barrier homeostasis, desquamation, and plasticity. It is formed from filaggrin proteolysis to small, hygroscopic molecules including amino acids. We hypothesized that common lipid extraction and soaking in water would alter the level of NMF in the upper stratum corneum (SC) and its biophysical properties. A novel method of measuring and quantifying the amino acid components of NMF is presented. Adhesive tapes were used to collect samples of the SC and were extracted with 6 mM perchloric acid for analysis by reverse-phase high-performance liquid chromatography (HPLC).The HPLC results were standardized to the amount of protein removed by the tapes. An increase in NMF was found with increased SC depth. Also, the combination of extraction and soaking was found to increase NMF loss relative to control or to extraction or soaking alone. Our results indicate that common skin care practices significantly influence the water binding materials in the upper SC. The findings have implications for the evaluation and formulation of skin care products.

pp. 23–29 The detrimental effects of prolonged water exposure on skin are well known. Information on the effects of short-term exposure, e.g. during bathing, showering, and hand washing, on Natural moisturizing factors (NMF) levels is limited. In an attempt to isolate the effects of soaking on the NMF, a time course for skin sample collection was devised in which adhesive tapes were applied 0.5 and 4 h after soaking of the treated arm. Significant decreases in NMF levels, quantified by high-performance liquid chromatography analysis of serial tape strips, were observed 0.5 h after soaking, with a replacement of NMF occurring by the four-hour mark. This replacement corresponds to a parallel rebound in skin pH also observed at these times. Stratum corneum (SC) hydration values, measured instrumentally as the rate of moisture accumulation (MAT), however, were depressed 0.5 h post-soaking and remained low 4 h later. In addition, significant increases in skin pH were observed during the immediate post-soak period. These findings suggest that short-term exposure to water alone produces significant changes in the SC.