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Biomedical subjects

J P Shenai

Publications and source records attributed to J P Shenai.

At least 19 recordsLinked to original sources
PubMed2006

Equations describing percentiles for birth weight, head circumference, and length of preterm infants.

OBJECTIVE: To describe growth of prematurely born infants and create a growth chart adequate to assess growth of infants with less than 29 completed weeks of gestation. STUDY DESIGN: Birth weight, head circumference and length measurements of 7,425 liveborn preterm infants from 1985 to 1997 were retrieved from a longitudinal database maintained by the neonatology division. The 3rd, 5th, 10th, 15th, 25th, 50th, 75th, 85th, 90th, 95th and 97th percentiles of each measurement were determined and used for mathematical modeling. RESULTS: Birth weight was described with an exponential function while head circumference and length were described with linear functions. A preterm growth chart for the 10th, 50th and 90th percentiles for birth weight, weight growth, head circumference and length was generated. CONCLUSION: The mathematical models of growth provide smooth representations of the percentiles across gestational ages.

Anthropometry↗
PubMed2001

Postnatal dexamethasone treatment and retinopathy of prematurity in very-low-birth-weight neonates.

Whether postnatal dexamethasone treatment for bronchopulmonary dysplasia (BPD) increases the risk of retinopathy of prematurity (ROP) in very-low-birth-weight (VLBW) neonates is uncertain. We performed a retrospective cohort study to determine the association between dexamethasone administered postnatally and the development of ROP in VLBW (< or = 1,250 g birth weight, < or = 32 weeks' gestational age at birth) neonates. The incidence of severe ROP (stage 2 or higher) was 26% among 72 infants who received no dexamethasone postnatally, 61% among 23 infants who received a low cumulative dexamethasone dose (< or = 1.8 mg/kg body weight), and 85% among 20 infants who received a high cumulative dexamethasone dose (> 1.8 mg/kg body weight). However, after adjustment for confounding covariates of prematurity and severity of lung disease by logistic regression analysis, we found no independent association between postnatal dexamethasone treatment and the incidence of severe ROP.

Birth Weight↗
PubMed2000

Vitamin A status and postnatal dexamethasone treatment in bronchopulmonary dysplasia.

OBJECTIVE: Vitamin A (retinol) plays an important role in epithelial regeneration during recovery from lung injury in bronchopulmonary dysplasia (BPD). Dexamethasone is used in the postnatal treatment of very low birth weight (VLBW) neonates with BPD. To test the hypothesis that the vitamin A status is critical for the beneficial pulmonary response to dexamethasone, we performed a prospective cohort study in which we characterized the changes in plasma concentrations of vitamin A and retinol-binding protein (RBP) in response to dexamethasone, and correlated these changes with the pulmonary outcome. METHODS: VLBW neonates (birth weight <1350 g, gestational age <31 weeks, postnatal age >10 days), who had presumptive diagnosis of severe BPD and need for high ventilatory support (fraction of inspired oxygen >/=.6, mean airway pressure >/=7 cm H(2)O), were treated with a seven-day course of dexamethasone (.5 mg/kg/d x 2 days,.25 mg/kg/d x 2 days,.1 mg/kg/d x 3 days). Plasma concentrations of vitamin A and RBP were determined sequentially at baseline, and during and after dexamethasone treatment. Pulmonary response to dexamethasone was graded daily using a composite ventilation score. The changes in plasma vitamin A and RBP concentrations were compared between infants with a positive (beneficial) pulmonary response to dexamethasone and those with a negative response. RESULTS: Among 23 infants studied, 13 showed a positive pulmonary response to dexamethasone, as indicated by successful weaning from supplemental oxygen and mechanical ventilation, whereas 10 showed a negative response. A significant, yet short-term, increase in plasma concentrations of both vitamin A and RBP was observed in most infants treated with dexamethasone. The plasma vitamin A and RBP responses to dexamethasone tended to be higher in infants with a positive pulmonary response than in those with a negative response. Accounting for gender, a vitamin A response with each 10.0 microg/dL increment in plasma vitamin A concentration was associated with a 60% increase in the odds favoring a positive pulmonary response to dexamethasone. CONCLUSION: Postnatal dexamethasone treatment in VLBW neonates with BPD induces a significant, yet short-term, increase in plasma concentrations of both vitamin A and RBP. This increase probably results from endogenous mobilization of vitamin A from the liver. Our data suggest that the beneficial pulmonary response to dexamethasone in infants with BPD is influenced, at least in part, by the vitamin A status, and that gender plays a role in this response.vitamin A, dexamethasone, bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1995

Vitamin A status and airway infection in mechanically ventilated very-low-birth-weight neonates.

Vitamin A (retinol) plays an important role in immunity. Respiratory and enteral infections in children are associated with low serum vitamin A concentrations that improve during recovery. To test the hypothesis that airway infection in very-low-birth-weight (VLBW) neonates likewise may be associated with a change in vitamin A status, we examined 20 VLBW neonates (selection criteria: birth weight 700-1300 g, gestational age 26-30 weeks, need for supplemental oxygen and mechanical ventilation for > 72 hr after birth) who were enrolled in the control group of a randomized clinical trial of vitamin A supplementation reported earlier. We studied changes in weekly measurements of plasma concentrations of vitamin A and retinol-binding protein (RBP) during 4 weeks following enrollment in the trial (postnatal day 4) and compared changes between periods with and without airway infections. Seventeen infants had 22 episodes of documented airway infection. Staphylococcus epidermidis was the predominant organism. Plasma vitamin A concentrations decreased during 19 out of 22. With airway infection (mean change: -4.1 to -18.6 micrograms/dL), while they increased during 37 out of 58 periods without airway infection (mean change: -0.2 to +5.8 micrograms/dl; P < 0.001). The mean (+/- SD) plasma vitamin A concentrations before, during, 1 week after, and 2 weeks after an episode of airway infection were 20.9 +/- 8.3, 9.7 +/- 4.1, 12.8 +/- 8.9, and 16.2 +/- 7.2 micrograms/dL, respectively. The mean value during airway infection was significantly lower than those before and two weeks after airway infection (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1995

Sequential evaluation of plasma retinol-binding protein response to vitamin A administration in very-low-birth-weight neonates.

Vitamin A (retinol) deficiency is associated with impaired healing from lung injury in very-low-birth-weight (VLBW) neonates susceptible to bronchopulmonary dysplasia (BPD). Vitamin A supplementation from birth may ameliorate this adverse outcome. We hypothesized that plasma retinol-binding protein (RBP) response to vitamin A administration, which provides a dynamic measure to vitamin A status, might be useful for early recognition of vitamin A deficiency in VLBW neonates at risk for BPD. We prospectively studied 20 VLBW neonates (inclusion criteria: birth weight < 1300 g, gestational age < 30 weeks, need for supplemental oxygen and mechanical ventilation for > 24 h after birth) who were eligible to receive vitamin A supplementation. In addition to sequential assessment of vitamin A status, we measured plasma RBP just before and 3 and 6 h after an intramuscular injection of vitamin A (2000 IU/kg retinyl palmitate) on Postnatal Days 1, 7, 15, 21, 29, and 43. The percentage increase in plasma RBP (delta-RBP) was calculated. A high plasma delta-RBP value ( > 8%) is indicative of vitamin A deficiency. Based on pulmonary outcome, the infants were divided into two groups: BPD (n = 12) and No BPD (n = 8). Mean vitamin A intake ranged from 1414 to 2114 IU/kg/day and did not differ between infant groups. Mean plasma vitamin A concentration increased from baseline levels on Postnatal Day 1 to levels within the desired range of 1.05-2.10 mumol/liter (30.0-60.0 micrograms/dl) during supplementation period in both infant groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchopulmonary Dysplasia↗
PubMed1994

Intramuscular versus enteral vitamin A supplementation in very low birth weight neonates.

We conducted a randomized trial in very low birth weight neonates (n = 51) to determine whether vitamin A supplementation by enteral administration would increase plasma vitamin A concentrations to the same degree as by intramuscular administration. Mean plasma vitamin A concentrations were significantly higher in the intramuscular-administration group than in the enteral-administration group by postnatal day 7; this effect persisted throughout the remainder of the trial. At the dosage used in this trial, vitamin A supplementation by the enteral route is not as effective as that by the intramuscular route in very low birth weight neonates.

Enteral Nutrition↗
PubMed1994

Effect of maternal dexamethasone treatment on fetal lung vitamin A stores in the perinatal rat.

Vitamin A (retinol) is essential for normal differentiation of developing respiratory epithelium. Significant vitamin A storage occurs in the fetal lung near term (gestational day 21) in the perinatal rat, and the developing lung may be dependent on these local vitamin A stores during growth and differentiation. The growth and differentiation of fetal lungs can be enhanced by maternal treatment with glucocorticosteroids. We conducted this study in rats to determine the effect of maternal dexamethasone treatment on the lung stores of vitamin A in the offspring. Vitamin A-sufficient pregnant rats were given by intraperitoneal injection a single dose of either dexamethasone (300 micrograms) or 0.9% saline solution on gestational day 16. High performance liquid chromatography was used to measure concentrations of vitamin A and its esters, retinyl palmitate and stearate, in fetal and neonatal lungs and livers at times ranging from gestational day 19 through 21, and from postnatal day 1 through 7. The concentrations of vitamin A esters in the lungs of fetuses and newborn pups of the dexamethasone-treated animals were significantly lower than those of the control group in all determinations, the values ranging between 22 and 50% of controls. In contrast, the concentrations of vitamin A esters in the livers did not differ significantly between study groups. We conclude that a prompt, sustained, and selective decrease in the fetal lung stores of vitamin A appears to occur following maternal antenatal dexamethasone treatment. This decrease in the fetal lung vitamin A stores might be due to increased utilization of vitamin A associated with enhanced differentiation of the fetal lung induced by maternal dexamethasone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Neonatal transport. Outreach educational program.

Neonatal transport is an integral part of a regionalized system of perinatal health care delivery. An effective outreach educational program promotes early identification of high-risk neonates, consultation, communication, and referral. The education offered in several formats also promotes optimal pretransport and intratransport stabilization of referred neonates. This improved stabilization may favorably influence the overall neonatal outcome. The impact of education in the region can be determined by a systematic review of referral patterns, standard of care during stabilization, and neonatal outcome. An organized outreach educational effort is therefore an essential aspect of any neonatal transport program.

Documentation↗
PubMed1991

A successful decade of regionalized perinatal care in Tennessee: the neonatal experience.

We hypothesized that successful implementation of regionalized perinatal care would result in early identification and antenatal referral of high-risk neonates, and also improved stabilization before and during transport of those transferred postnatally. We conducted a retrospective study of demographic characteristics and transport outcome in two defined groups of neonates transported to regional perinatal centers in Tennessee, one group (n = 218) from the first year of regionalization (1975), and a second group (n = 261) from the 12th year (1986). The percentage of outborn infants decreased, from 50% of all admissions in 1975 to 22% in 1986 (P = .005). Likewise, the percentage of low-birthweight neonates transported after birth decreased, from 59% of all transports to 32% (P = .002). The frequency of stabilization measures performed before and during transport increased between study years (intravenous line placement: 12% to 58%, P = .0001; assisted ventilation: 10% to 33%, P = .001). The incidence of complications during transport decreased between study years (cyanosis: 25% to 8%, P = .0001; hypothermia: 30% to 3%, P = .0001; acidemia: 33% to 13%, P = .011). Both transport-related mortality and neonatal mortality decreased between study years (2.8% to 0.8%, P = .043; 17% to 7%, P = .0001, respectively). We conclude that regionalization during its first decade has been successful in improving perinatal care in Tennessee as indicated by favorable changes in referral patterns and improved outcome of transported neonates.

Humans↗
PubMed1990

Plasma retinol-binding protein response to vitamin A administration in infants susceptible to bronchopulmonary dysplasia.

We hypothesized that changes in plasma retinol-binding protein (RBP) concentration in response to vitamin A administration might be useful for evaluating vitamin A status of very low birth weight infants susceptible to bronchopulmonary dysplasia. We prospectively studied 24 consecutively admitted neonates (birth weight less than 1350 gm, gestational age less than 31 weeks, ventilator dependent for greater than 24 hours after birth), who were eligible to receive 2000 IU supplemental vitamin A by intramuscular injection on postnatal day 1 and on alternate days thereafter for 28 days. In addition to serial assessment of vitamin A status, we measured plasma RBP just before and 1, 3, and 6 hours after an intramuscular injection of vitamin A (2000 IU/kg retinyl palmitate) on days 1 and 28. The percent increase in plasma RBP (delta-RBP) was high (mean +/- SD: 61 +/- 37%) and plasma vitamin A and RBP values were low on day 1, indicative of vitamin A deficiency. Supplemental vitamin A improved vitamin A status of all infants as shown by low delta-RBP (mean +/- SD: 8 +/- 9%) and normal plasma vitamin A and RBP values on day 28. Bronchopulmonary dysplasia was diagnosed in 12 of 24 infants. Infants with bronchopulmonary dysplasia had a higher mean (+/- SD) delta-RBP on day 28 than those without bronchopulmonary dysplasia (13 +/- 10% vs 3 +/- 3%, p less than 0.01), indicative of persistence of low vitamin A status in infants with lung disease despite supplementation. We conclude that the plasma RBP response to vitamin A is a useful indicator of vitamin A status in very low birth weight infants. Although vitamin A supplementation at the dosage used in this study normalizes conventional plasma indexes of vitamin A in very low birth weight infants, the plasma RBP response to vitamin A may continue to reflect persistence of low vitamin A status in the more immature infants with significant lung disease. We suggest that the plasma RBP response to vitamin A may be a useful functional test in such infants.

Bronchopulmonary Dysplasia↗
PubMed1990

Vitamin A storage in lungs during perinatal development in the rat.

We examined the ontogeny of vitamin A storage in fetal and neonatal lungs during perinatal development in the rat. High-performance liquid chromatography was used to measure concentrations of vitamin A and its esters, retinyl palmitate and stearate, in various fetal and neonatal tissues at times ranging from gestational day 14 through 21, and from postnatal day 1 through 21. The data show that significant vitamin A storage occurs in the fetal lung during the latter one-third of prenatal life. Depletion of these stores that begins before birth and continues into the early postnatal period suggests that the developing lung may be dependent on these local vitamin A stores during active growth and differentiation. The utilization of vitamin A stores in the developing lung appears to be independent of the liver stores of vitamin A.

Animals↗
PubMed1990

Effect of maternal vitamin-A administration on fetal lung vitamin-A stores in the perinatal rat.

Vitamin A (retinol) is essential for normal differentiation and integrity of developing respiratory epithelium and its deficiency has been linked to an increased susceptibility to lung injury. Because significant vitamin-A storage occurs in the fetal lung near term in the perinatal rat, prematurely born animals deprived of adequate stores in their lungs may be susceptible to the adverse effects of vitamin-A deficiency. It would be desirable if lung vitamin-A stores could be augmented with maternal administration, but the feasibility of this strategy has not been reported. We therefore conducted this study in rats to determine whether maternal administration of vitamin A could increase the lung stores of vitamin A in the offspring. Vitamin-A-sufficient pregnant rats were given a single dose of either vitamin A (50,000 IU retinyl palmitate) or 0.9% saline solution on gestational day 16 (term = 21 days) by the intragastric route. High-performance liquid chromatography was used to measure concentrations of vitamin A and its esters in fetal and neonatal lungs and livers at times ranging from gestational day 17 through 21, and from postnatal day 1 through 14. The concentrations of vitamin-A esters in the lungs of fetuses and newborn pups of the vitamin-A-treated animals were significantly (1.7- to 7.1-fold) higher than those of the control group. This increase in the lung vitamin-A ester concentrations was seen within 24 h of maternal administration and persisted throughout the 14-day postnatal period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Clinical trial of vitamin A supplementation in infants susceptible to bronchopulmonary dysplasia.

We conducted a randomized, double-blind, controlled trial to determine whether vitamin A supplementation from early postnatal life could reduce the morbidity associated with bronchopulmonary dysplasia in very low birth weight (VLBW) neonates. Forty VLBW neonates (700 to 1300 g birth weight, 26 to 30 weeks gestational age), who were oxygen dependent and required mechanical ventilation for at least 72 hours after birth, were given by the intramuscular route either supplemental vitamin A (retinyl palmitate 2000 IU) or 0.9% saline solution on postnatal day 4 and every other day thereafter for a total of 14 injections over 28 days. The study groups were comparable in gestational maturity, clinical characteristics, initial lung disease, and vitamin A status at entry into the trial. Vitamin A administration resulted in significantly higher mean plasma concentrations of vitamin A and retinol-binding protein in treated infants compared with controls. Bronchopulmonary dysplasia was diagnosed in nine of 20 infants given vitamin A supplement and in 17 of 20 control infants (P less than 0.008). Four of 19 infants in the vitamin A group and 11 of 20 in the control group required mechanical ventilation on study day 28 (P less than 0.029). The need for supplemental oxygen, mechanical ventilation, and intensive care was reduced in infants given vitamin A supplement compared with controls. Airway infection and retinopathy of prematurity were less frequent in the vitamin A group. We conclude that vitamin A supplementation at the dosage used in this trial in VLBW neonates not only improves their vitamin A status but also appears to promote regenerative healing from lung injury, as evidenced by a decrease in the morbidity associated with bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1985

Vitamin A status of neonates with bronchopulmonary dysplasia.

We prospectively assessed and compared the vitamin A status of two groups of preterm neonates (less than 1500 g birth weight, less than 32 wk gestation), one who developed clinical and radiographic evidence of bronchopulmonary dysplasia (BPD) (n = 10), and the other (control) who developed no significant lung disease (n = 8). The infants with BPD in this study required prolonged mechanical ventilation and supplemental O2 therapy, and had a higher incidence of cardiorespiratory complications when compared to controls. Their mean plasma vitamin A concentrations were significantly lower than those of controls at four sampling times in the 1st postnatal month. In contrast to the controls, infants with BPD showed a substantial decline in their plasma vitamin A concentrations from the initial values, and a high percentage of individual values of plasma vitamin A concentration in these infants were less than 10 micrograms/dl during the 8-wk postnatal period of observation. Delayed establishment of gastrointestinal feeding and a lower vitamin A intake in these infants relative to controls may have accounted for this decline. Our data show that preterm neonates who develop BPD have suboptimal plasma vitamin A concentrations for extended periods of time postnatally. We speculate that the necrotizing bronchiolitis and squamous metaplasia of conducting airways associated with vitamin A deficiency could influence the orderly repair of lung injury in susceptible neonates who are mechanically ventilated and could contribute to the pathophysiology of BPD in these infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchopulmonary Dysplasia↗
PubMed1985

Liver vitamin A reserves of very low birth weight neonates.

This study assessed the liver vitamin A concentrations at birth in a group of very low birth weight neonates (n = 25) (less than 1500 g birth weight, less than 32 wk gestation), dying within 24 h of birth, prior to possible changes in vitamin A status induced by postnatal intervention. Serum concentrations of vitamin A and retinol-binding protein were also measured in 16 of these neonates. The mean (+/- SD) liver vitamin A concentration was 30.0 +/- 12.9 micrograms/g (range 2.0-49.0 micrograms/g). The mean (+/- SD) serum vitamin A concentration was 13.0 +/- 4.7 micrograms/dl (range 6.7-22.8 micrograms/dl). The mean (+/- SD) serum retinol-binding protein concentration was 2.2 +/- 0.8 mg/dl (range 1.5-4.8 mg/dl). Liver vitamin A, serum vitamin A, and serum retinol-binding protein concentrations did not correlate significantly with gestational age or birth weight. Linear regression analysis did not show a significant correlation between liver vitamin A, and serum vitamin A or retinol-binding protein concentrations. This study provides reference values for vitamin A concentrations at birth in very low birth weight neonates, which may be helpful in future studies designed to evaluate postnatal changes in the vitamin A status of these high-risk neonates.

Female↗