Harry S Dweck

A Noninvasive Approach to Body Composition in the Neonate: Dynamic Skinfold Measurements

Extract: Midtricipital (MT) and subscapular (SS) skinfolds were measured within 24 hr of birth in 23 normally grown mature (NG-M); 23 normally grown premature (NG-P); 6 intrauterine growth-retarded mature (IGR-M); and 7 intrauterine growth-retarded premature (IGR-P) infants. A rapid initial decrease in measured skinfold thickness (SFT) occurred after application of a Harpenden caliper, but readings stabilized by 60 s (SFT60). Measurements were recorded at 15 and 60 s. The difference between 15− and 60-s readings was expressed in percentage of the 15-s reading (percentage ΔSFT).The amount of subcutaneous fat, estimated from the SFT60 measurements, was affected by duration of gestation in the NG-M and NG-P and the IGR-M and IGR-P groups. In both NG groups, good linear correlations with birth weight (r = 0.852 at MT and 0.874 at SS, P < 0.001) and with gestational age (r = 0.842 at MT and r = 0.804 at SS, p < 0.001) were evident. Values for intrauterine growth-retarded infants deviated markedly from the mean SFT60 expected for their gestational age.Percentage ΔSFT was affected by duration of maturation but not by impaired intrauterine growth. It correlated with gestational age (r = −0.777 at MT and −0.773 at SS, P < 0.001) and with maximal postnatal weight loss (r = 0.579 at MT and 0.553 at SS, P < 0.001) in all groups and with birth weight in the premature groups only (r = −0.479 at MT and −0.520 at SS, P < 0.01). The similarity of these trends with those of direct extracellular water measurements suggested that percentage ΔSFT may be an estimate of subcutaneous interstitial water.Speculation: Changes in body composition during fetal life include fat deposition in the subcutaneous and internal body stores and a decrease in the proportion of body weight occupied by water. Intrauterine growth retardation results in lower fat stores and expansion of all body water compartments. The present data suggest that skinfold thickness recorded 60 s after caliper application and the difference between the 15-and 60-s readings provide estimates of fat stores and subcutaneous interstitial water, respectively. Caliper skinfold measurements can therefore be used for noninvasive studies of perinatal body composition and nutrition.

Effect of open-heart surgery on the body composition of infants and young children.

Summary: Body water content and distribution were determined in 16 children aged 2 wk to 28 months before and after open-heart surgery for correction of congenital cardiac defects. Operative procedures were performed using hypothermia and extracorporeal oxygenation. On the day before and the day after surgery, total body water was estimated as the antipyrine space (APS); extracellular water, as the corrected bromide space (CBS), and plasma volume, as the 10-min T-1824-albumin space. Intracellular water (ICW) was assumed to be the difference between APS and CBS; interstitial water was calculated from plasma volume and CBS. Before initiation and after completion of extracorporeal circulation, a pectoral muscle biopsy was performed, and a blood sample was obtained. Muscle total water (TW) content was determined by desiccation, extracellular water (ECW) was estimated as the corrected chloride space, and ICW was assumed to be the difference between TW and ECW. Plasma sodium, potassium, chloride, glucose, and osmolality contents were determined by routine methods. All studies were not completed in all patients.Although APS and CBS increased in eight of 11 children, mean APS (± S.E.) before and after surgery (662 ± 28.0 versus 714 ± 37.2 ml/kg) and mean CBS (335 ± 30.5 versus 358 ± 15.5 ml/kg) were not statistically different. Mean ICW changed neither in relation to body weight (328 ± 28.0 versus 355 ± 34.2 ml/kg) nor in relation to APS (ICW/APS ratio = 0.48 ± 0.040 versus 0.49 ± 0.010). Neither mean PV (54 ± 4.0 versus 56 ± 2.8 ml/kg) nor mean blood volume (92 ± 5.4 versus 90 ± 5.5 ml/kg) changed significantly. Mean interstitial water increased by 9 to 68% over preoperative values in all but one patient (238 ± 10.4 versus 305 ± 13.4 ml/kg; P < 0.01).Muscle composition was not affected by the procedure. Mean TW was 79 ± 1.3 ml/100 g before extracorporeal circulation and 78 ± 0.8 ml/100 g afterwards whereas ECW averaged 32 ± 4.4 and 36 ± 3.4 ml/100 g, and ICW averaged 48 ± 4.6 and 42 ± 2.9 ml/100 g. Mean ICW/TW ratios were 0.60 ± 0.055 and 0.54 ± 0.040 ml/100 g.Although mean plasma sodium (142 ± 3.5 versus 139 ± 2.4 mEq/liter) and potassium (3.3 ± 0.16 versus 3.6 ± 0.15 mEq/liter) concentrations did not change appreciably during extracorporeal circulation; mean plasma chloride content decreased (108 ± 2.9 versus 100 ± 2.0 mEq/liter; P < .002). Plasma glucose averaged 60 mg/dl more at completion of the procedure, increasing from a mean of 223 ± 25.6 mg/dl to a mean of 283 ± 5.3 mg/dl (P < 0.05). Plasma osmolality increased in five of eight children, but mean osmolalities were similar before and after extracorporeal circulation (301 ± 8.9 versus 303 ± 5.4 mOsm/kg).These data suggest that a childs organism does not react complacently to the invasive procedures associated with open-heart surgery. Further research into effects of these procedures and into means of minimizing undesirable homeostatic disturbances is warranted.Speculation: Body composition of adult patients has been shown to be acutely altered by open-heart surgery with hypothermia and extracorporeal circulation. Our data suggest that similar changes occur in young children who are subjected to these procedures. Because small children, especially those afflicted with major congenital defects, have limited homeostatic capabilities, the risk of these disturbances becoming life-threatening is increased. Means of minimizing them need be devised.

Umbilical artery catheters and blood flow velocities in the superior mesenteric artery: Effect of insertion, removal, aspiration, and bolus infusion

We studied whether umbilical artery catheters (UACs) affect blood flow in the superior mesenteric artery (SMA) of neonates.

Early intravenous dexamethasone (dex) for the prevention of BPD in surfactant treated babies with RDS. 1138

Early intravenous dexamethasone (dex) for the prevention of BPD in surfactant treated babies with RDS. 1138

Endothelin-1 levels in the maternal-fetal dyad.

The aim of this study was to determine the distribution of ET-1 levels in the term maternal-fetal dyad. We also compared the levels of ET-1 between umbilical vessels and assessed the effect of labor on the concentration of ET-1. The ET-1 levels were measured in plasma from 18 term maternal-infant pairs. Amniotic fluid ET-1 levels were also measured in 9 of these pregnancies. The ET-1 levels were determined by radioimmunoassay (RIA) after extraction of plasma using Sep-Pak C18 cartridges. There were no significant differences in the ET-1 levels between the umbilical artery and vein. However, there were significant differences in the umbilical artery concentration in women who labored when compared with those delivered without labor (6.0 +/- 1.1 vs. 2.7 +/- 0.7 pg/ml; t test, p = 0.022). ET-1 levels were lowest in the maternal plasma (0.9 +/- 0.2 pg/ml) and highest in the amniotic fluid (83 +/- 15 pg/ml). Assuming that elevated plasma ET-1 levels reflect increased bioactivity, the higher mean ET-1 levels in the cord vessels and in the amniotic fluid when compared to maternal levels suggest a role for ET-1 in the regulation of the fetoplacental circulation and in the constriction of blood vessels in the uterus after parturition. The higher levels of ET-1 in the umbilical artery of women who underwent labor implies that ET-1 is released as a result of the stress of labor.

Specificity of glycosaminoglycan suppression of endothelin-1 production by human umbilical vein endothelial cells.

Endothelin-1 (ET-1) is the most potent vasoconstrictor peptide found in nature. Its production is stimulated by thrombin. By inhibiting thrombin we have previously shown that heparin, a highly negatively-charged glycosaminoglycan (GAG), suppresses the production of ET-1 by cultured human umbilical vein endothelial cells (HUVEC). The purpose of our study is to determine the effect of other GAGs and related compounds on ET-1 production. The GAGs and related compounds used in the study were: chondroitin sulfate A, chondroitin sulfate B, chondroitin sulfate C, fucoidin, low molecular weight dextran sulfate, high molecular weight dextran sulfate, and hyaluronan. HUVEC were incubated for 48 hr with media containing these GAGs and related compounds and with media without GAG as control. ET-1 levels were measured by radioimmunoassay. GAGs and related molecules with higher sulfate content, heparin, chondroitin sulfate B, low and high molecular weight dextran sulfates significantly suppressed ET-1 production by HUVEC. Fucoidin also suppressed ET-1 production despite its lower sulfate content, probably because of its structural similarity to heparin. These compounds may be useful for future in vivo studies.

Release of superoxide dismutase activity from human umbilical veins by heparin.

OBJECTIVE:This study evaluated superoxide dismutase activity released from human umbilical veins incubated with different doses of heparin and examined at different time points.STUDY DESIGN:Umbilical veins of fresh cords from full term babies were incubated with 175 or 1 U/ml of heparin at one end while the other end was incubated without heparin as control. Specimens were obtained at 10 minutes and 24 hours (high-dose) or at 10 minutes and 60 minutes (low-dose). Superoxide dismutase activity was measured by the cytochrome c method. Results were analyzed using Student’s paired t test.RESULTS:A time-dependent release of superoxide dismutase activity into the buffer was observed in both heparin specimens as well as in control specimens. The difference in release in the presence of heparin was of statistical significance, compared with the controls.CONCLUSION:Because heparin is routinely used as an anticoagulant to maintain the patency of umbilical catheters, we conclude that this usage may alter a newborn’s response to oxygen free radical damage by changes in superoxide dismutase activity.

LOW MOLECULAR WEIGHT HEPARIN FRAGMENTS SUPPRESS ET-1 PRODUCTION BY HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS. † 1542

LOW MOLECULAR WEIGHT HEPARIN FRAGMENTS SUPPRESS ET-1 PRODUCTION BY HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS. † 1542

SURFACTANT PROPHYLAXIS AS IMMEDIATE BOLUS (IB) VERSUS POST-VENTILATORY ALIQUOTS (PVA): A MULTICENTER RANDOMIZED TRIAL. † 1311

SURFACTANT PROPHYLAXIS AS IMMEDIATE BOLUS (IB) VERSUS POST-VENTILATORY ALIQUOTS (PVA): A MULTICENTER RANDOMIZED TRIAL. † 1311

Survival and Mean Length of Stay (MLOS) of Tiny Premature Infants in a Regional Neonatal Intensive Care Unit (RNICU) |[dagger]| 1322

We compared the survival of 1,012 tiny premature infants of birth weight(BW) ≤ 1000 grams admitted to the Regional Neonatal Intensive Care Unit(RNICU) in three 5-year periods: 1982-86 (Period I), 1987-91 (Period II), 1992-97 (Period III) analyzed by Student t-test and χ2. Each BW group in each period had similar mean BW, number of males and proportion of SGA babies (7-10%). Table