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Biomedical subjects

S Dollberg

Publications and source records attributed to S Dollberg.

At least 19 recordsLinked to original sources
PubMed1999

Effect of pulsed dexamethasone therapy on tolerance of intravenously administered lipids in extremely low birth weight infants.

We investigated the effect of dexamethasone on parenteral lipid tolerance in 7-day-old extremely low birth weight infants (n = 28) in a randomized, double-blind trial. Serum triglycerides were measured before and after 3 days of dexamethasone or placebo treatment. Infants treated with dexamethasone responded with higher triglyceride concentrations and greater sensitivity to incremental increases in the intravenous lipid dose.

Dexamethasone↗
PubMed1999

Nucleated red blood cells in infants of smoking mothers.

OBJECTIVE: To evaluate whether the absolute nucleated red blood cell (RBC) count is elevated in term, appropriate for gestational age (AGA) infants born to smoking women. METHODS: We compared absolute nucleated RBC counts taken during the first 12 hours of life in two groups of term, vaginally delivered, AGA infants, one group born to mothers who smoked during pregnancy (n = 30) and the other born to mothers who did not smoke (n = 30). We excluded infants of women with diabetes, hypertension, or alcohol or drug abuse, and infants with heart rate abnormalities, hemolysis, blood loss, or chromosomal anomalies. RESULTS: There were no differences between the groups in birth weight, gestational age, maternal age, gravidity, parity, maternal analgesia during labor, 1- and 5-minute Apgar scores, corrected white blood cell counts, lymphocyte counts, or hematocrits. The median absolute nucleated RBC count in infants of smoking mothers was 0.5 x 10(9)/L (range 0 to 5.0) versus 0.0005 x 10(9)/L (range 0 to 0.6) in nonsmoking controls (P < .002). Regression analysis that included Apgar scores, gestational age, and number of cigarettes smoked per day showed a significant correlation of absolute nucleated RBC count only with the number of cigarettes smoked per day (P < .001). CONCLUSION: At birth, term AGA infants born to smoking mothers have increased circulating absolute nucleated RBC counts compared with controls. The absolute nucleated RBC count in newborns correlates with the number of cigarettes smoked during pregnancy.

Adult↗
PubMed1998

Changes in skin blood flow over the foot with warming of the contralateral heel.

Vasospasm in one leg is a common complication of umbilical artery catheterization in preterm infants. It is a common practice to wrap the contralateral leg in a warm washcloth. The rationale for this intervention is to induce reflex vasodilatation of the affected extremity, thereby avoiding the necessity to remove or replace the catheter. This study tested the hypothesis that heating the contralateral extremity in preterm infants would increase peripheral blood flow to the contralateral foot. Ten stable preterm infants who had had no umbilical catheter inserted for at least 2 weeks were studied. Skin perfusion was measured using the laser Doppler method in the distal leg after heating of the opposite foot to 40.5 degrees C. Blood flow to the skin of the contralateral foot was measured before and after warming the ipsilateral one. The skin blood flow measured with and without heat application to the contralateral foot was not significantly different. Direct heat does not induce contralateral reflex vasodilatation in the foot of preterm infants.

Catheterization↗
PubMed1997

Nitric oxide synthase activity in umbilical and placental vascular tissue of gestational diabetic pregnancies.

OBJECTIVE: Nitric oxide (NO) synthase activity in the fetal-placental vasculature of gestational diabetic pregnancies was compared to non-diabetic controls. METHODS: Placentae were collected from non-diabetic deliveries (n = 5) and from patients with gestational diabetes (n = 8). Umbilical cord and chorionic plate arteries and veins and stem villous vessels were quickly dissected out, cleaned of contaminating tissue, snap frozen in liquid nitrogen and stored at -80 degrees C. NO synthase activity was measured in the homogenate of these vessels by the arginine to citrulline conversion assay using 5 microM 3H-L-arginine with 1 mM NADPH, 100 microM free calcium, 50 units/ml calmodulin, 10 microM tetrahydrobiopterin and 2 microM flavin adenine dinucleotide with 45-min incubation at 27 degrees C. Enzyme activity was expressed as picomoles of 3H-L-citrulline formed per milligram of protein per minute. RESULTS: No significant differences in NO synthase activity were found between non-diabetic and gestational diabetics for umbilical cord artery (0.58 +/- 0.22 vs. 0.19 +/- 0.06), cord vein (0.39 +/- 0.21 vs. 0.07 +/- 0.03), chorionic plate artery (0.32 +/- 0.14 vs. 0.26 +/- 0.19) or vein (0.41 +/- 0.15 vs. 0.22 +/- 0.06), respectively (mean +/- SEM). Significantly greater activity was found in stem villous vessels of non-diabetic placentae (5.64 +/- 2.0) compared to those of gestational diabetic placentae (0.48 +/- 0.19; p < 0.01). CONCLUSION: The reduced blood flow and increased vascular resistance observed in diabetic pregnancies may be due to decreased NO synthesis and activity in the stem villous vessels which are the major determinants of resistance in the fetal-placental vasculature.

Diabetes, Gestational↗
PubMed1995

Effect of different phototherapy lights on incubator characteristics and dynamics under three modes of servocontrol.

Phototherapy is one of the most common therapeutic interventions in modern neonatal medicine. Analysis of physiological responses to phototherapy requires understanding the physical effects of incident light under different modes of environmental control. In this study, we tested the effect of initiation of phototherapy under laboratory conditions in a convective incubator maintained in three clinically used servocontrol modes. Under conditions of air servocontrol, the initiation of phototherapy resulted in an abrupt sustained increase in the surface temperature of an infant simulator (a blackened aluminum disc). In contrast, when the surface (skin) temperature was the controlled variable, there was a profound drop in the incubator air temperature. An algorithm that simultaneously controlled both the skin and the air temperatures showed intermediate effects. Under conditions of skin servocontrol, fluctuations in air and environmental temperatures were observed for a period of 3 hours before steady state was reached. These findings are most clearly demonstrated using phase plane plotting techniques. We conclude that wide, abrupt, and sustained changes in the thermal environment of an incubator occur after phototherapy is initiated. Such changes must be anticipated in physiological studies using phototherapy.

Algorithms↗
PubMed1995

Urinary nitrite and nitrate concentrations in patients with idiopathic persistent pulmonary hypertension of the newborn and effect of extracorporeal membrane oxygenation.

Persistent pulmonary hypertension of the newborn (PPHN) often requires extracorporeal membrane oxygenation (ECMO), during which time pulmonary vascular resistance gradually declines. Nitric oxide (NO) is a recently recognized pulmonary vasodilator, but its role in PPHN is unknown. We tested the hypothesis that the concentrations of the urinary metabolites of NO, i.e. nitrite and nitrate, are reduced in patients with PPHN and increase during ECMO as the PPHN resolves. Eight newborn infants with PPHN on ECMO were studied. Daily urinary concentrations of nitrite/nitrate were measured. We found that mean urinary concentrations of nitrite/nitrate were lower in patients with PPHN than in 47 controls without pulmonary disease (p < 0.005). Urinary nitrite/nitrate concentration showed an initial increase after initiation of ECMO. However, a decrease to concentrations still lower than controls occurred on the day before decannulation. We conclude that intrinsic NO production is significantly lower in patients with PPHN than in controls but increases with oxygenation. We speculate that decreased urinary NO metabolite concentrations imply a role for NO deficiency in the pathogenesis of PPHN.

Extracorporeal Membrane Oxygenation↗
PubMed1994

Are multiple cesarean sections safe?

To assess the maternal and neonatal risk associated with high-order cesarean sections, a case-control study was carried out in two university affiliated maternity wards. The outcome of 154 pregnancies of women undergoing cesarean section for the 4th time or more was compared with 148 women sectioned for the 2nd or 3rd time and 132 women of similar age and parity after spontaneous birth. The main outcome measures were maternal operative and postoperative morbidity and neonatal prematurity and its complications, Apgar scores, and the need for intensive care. Women undergoing multiple (> or = 4) cesarean sections had significantly more intra-abdominal adhesions (P < 0.0001) than women sectioned for the 2nd or 3rd time. However, the time interval from incision to delivery and the total duration of operation were similar. The postoperative course was not adversely affected by multiple cesarean sections. A high incidence (16.2%) of preterm cesarean deliveries was noted in the study group. This was due to non-elective repeat cesarean delivery rather than to poor timing of scheduled cesarean sections. The significantly increased (P < 0.05) need for neonatal intensive care was explained by the higher occurrence of prematurity. Low Apgar scores (< or = 7) at 1 and 5 min were significantly (P < 0.01) related to multiple cesarean sections, even after controlling for the effect of gestational age. We conclude that multiple cesarean sections pose little risk for the mother, but may be associated with increased neonatal risk, attributed mainly to preterm non-elective cesarean sections.

Adult↗
PubMed1994

Effect of insulated skin probes to increase skin-to-environmental temperature gradients of preterm infants cared for in convective incubators.

Thermal support systems for premature infants that are based on skin servocontrol depend on accurate measurement of skin surface temperature. We examined prospectively the effect of probe insulation to alter measured skin temperature in 10 preterm infants. The use of insulated probes resulted in significant alteration in incubator servocontrol, with lower incubator air temperatures and higher skin-to-environment temperature gradients.

Equipment Design↗
PubMed1993

A noninvasive transcutaneous alternative to rectal thermometry for continuous measurement of core temperature in the piglet.

Deep body temperature is an important and accepted index of health status in newborn infants. There are no easily used accurate methods for continuous deep body temperature measurements. Oral and tympanic membrane temperatures correlate well with rectal temperature but are not easily adapted to continuous measurement. We devised a noninvasive transcutaneous temperature sensor for continuous deep body temperature measurement that relies on the principle that, under steady state conditions, the temperature at the thermally insulated surface of a warm body, i.e. a zero heat loss surface, will be in equilibrium with the warmest part of the body. We used a standard clinical temperature probe placed between the skin and the mattress and attached to the skin with a foam adhesive disk. We used standard skin temperature probe attachment disks, which are also designed to provide thermal insulation to the skin temperature probe. We tested the hypothesis that this transcutaneous temperature would track body temperature as indicated by rectal temperature. In six anesthetized (pentobarbital) newborn piglets (1600 +/- 200 g) placed on their abdomen in a convectively warmed infant incubator, we measured continuously the following temperatures for 5 h: transcutaneous over lower and upper abdomen, brown fat, rectal, and descending aorta. To examine the influence of environment, we varied the incubator air temperature between 32 degrees and 36 degrees C. Both transcutaneous temperatures tracked the rectal temperature, within 0.2 degree C for transcutaneous over lower abdomen and within 0.3 degree C for transcutaneous over upper abdomen.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1992

The prevalence of valvular regurgitation in children with structurally normal hearts: a color Doppler echocardiographic study.

To determine the prevalence of valvular regurgitation in children (from birth to 14 years old) with structurally normal hearts, the records of 1360 consecutive patients referred for echocardiographic and Doppler examination were analyzed. A total of 461 (33.9%) patients were found to have structurally normal hearts. Flow patterns across the four valves were examined by pulsed, continuous-wave, and color Doppler imaging techniques. Regurgitation was detected in 124 (26.9%). Pulmonic regurgitation was most commonly found and was detected in 101 (21.9%) patients, tricuspid regurgitation in 29 (6.3%), and mitral regurgitation in 11 (2.4%). Aortic regurgitation was not found. Regurgitation of one valve occurred in 106 (23.0%) patients and of two valves in 18 (3.9%) patients. No patient had regurgitation of more than two valves. The prevalence of pulmonic regurgitation increased significantly with age (p less than 0.0001), whereas the prevalence of mitral, tricuspid, and bivalvular regurgitation did not change with age. Valvular regurgitation was trivial or mild in 87% of patients. Thus mild valvular regurgitation is commonly found in children with structurally normal hearts.

Adolescent↗
PubMed1992

Eicosanoids in hypoxic insult to neonatal rabbit bowel.

Eicosanoids, derivatives of arachidonic acid, play a role in several inflammatory diseases of the bowel. To determine whether prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and leukotriene C4D4E4 (LTC4D4E4), have a role in hypoxic insult to the intestine, we examined the levels of these mediators in a hypoxic neonatal rabbit model. One group of animals underwent hypoxic insult postnatally, the second group did not undergo hypoxia and served as a control. The levels of PGE2, LTB4, and LTC4D4E4 were determined by radioimmunoassay. PGE2 in the hypoxic group was 1,779 +/- 142 pg/mg protein (mean +/- SD) as opposed to 2,380 +/- 197 pg/mg protein in the control group (p less than 0.02). LTB4 level was 5,446 +/- 3,492 pg/mg protein in the hypoxic rabbits and 3,362 +/- 2,570 pg/mg protein in the control group (p less than 0.03). There was no statistically significant difference in the level of LTC4D4E4 between the two groups. Our study shows that hypoxia shifts the arachidonic acid metabolism toward enhanced lipoxygenase activity with a resultant increase in LTB4 levels and a concomitant decrease in cyclooxygenase activity with reduced PGE2 levels in the bowel. The shift in the balance between these eicosanoids may play a role in the pathogenesis of ischemic-hypoxic bowel diseases by enhancing the inflammatory response in the intestine, and simultaneously, diminishing cytoprotection.

Animals↗
PubMed1992

A 2-year prospective study of very low birthweight infants.

A prospective 2-year follow-up study was carried out on 68 of the 69 surviving very low birthweight (VLBW) infants (< 1,501 g) born in Bikur Holim Hospital in the years 1985-87. The aims were a) to determine the incidence of major disability, and b) to compare the 2-year outcome of VLBW infants without major disability with that of a control group of full-term small-for-gestational-age infants, using the Mental Development Index (MDI) of the Bayley Scales. Mean birthweight of the VLBW infants was 1,234 +/- 216 g and mean gestational age was 30.7 +/- 2.4 weeks. Their neonatal mortality during the study period was 29.8%. Major disability was diagnosed in 11/68 infants (16%). At age 2 years there was no significant difference between the mean MDI of the VLBW infants without major disability (97.7 +/- 19.5) and that of the controls (99.7 +/- 17.0). These data, representing the outcome of VLBW infants from a community-based hospital with neonatal intensive care facilities, are comparable in incidence of major disability with data of large tertiary centers. Cognitive ability of VLBW infants without major disability at age 2 years was equivalent to that of their full-term peers.

Analysis of Variance↗
PubMed1992

Is cord blood erythropoietin a marker of intrapartum hypoxia?

A sensitive assay was used to compare the biological activity of cord serum erythropoietin in two groups of infants born with or without labor-induced hypoxia. The mean cord serum erythropoietin activity in 161 infants delivered after vaginal labor was 116 +/- 36 mU/mL, and was indistinguishable from that observed in 23 infants delivered by preplanned, elective cesarean section, 114 +/- 12 mU/mL (P = .75). The bioassay measured effective erythropoietin activity, including the contribution of potentiators in serum. These results indicate that duration and intensity of labor are insufficient to cause a significant increase in effective erythropoietin activity.

Cesarean Section↗