Biomedical subjects
Publications and source records attributed to M Mullett.
A newborn girl with ring chromosome 1 is described. The letter reports the chromosome analysis of peripheral blood lymphocytes with 46,XX,r(1)(p36.3q44) and evidence of ring instability in umbilical cord fibroblasts.
OBJECTIVE: To examine the influence of gestational age on seizures in the neonatal intensive care unit. STUDY DESIGN: A cohort of 4165 neonates admitted to a university intensive care unit between 1986 and 1995. The incidence, time of onset, and etiology of neonatal seizures in the cohort were distributed by gestational age. Logistic regression and t test were used to examine the relationship between gestational age and seizures in the neonatal intensive care unit. RESULTS: Seizures occurred in 356 (8.6%) infants. The seizure rate was parabolically related to gestational age, such that infants at 30 to 36 weeks' gestation had a 4.8% rate compared with 11.9% and 14.1% rates for infants < 30 and > 36 weeks, respectively (p < 0.001). Seizures manifested earlier in infants < 30 weeks (2.3 +/- 5.6 days of life) and > 36 weeks (3.7 +/- 8.7 days) gestational age compared with neonates 30 to 36 weeks (10.4 +/- 14.5 days) (p < 0.001). Intraventricular hemorrhage was the principal etiology underlying the higher seizure rate for infants < 30 weeks (p < 0.001). Hypoxic-ischemic encephalopathy and congenital malformations were primary factors for infants > 36 weeks (p < 0.01). Nervous system infections were evenly distributed across gestational age. CONCLUSION: Gestational age exerts a considerable influence on the incidence, onset, and etiology of neonatal seizures.
In a multicenter, double-blind, placebo-controlled trial that enrolled 215 premature infants with birth weights of 500 to 699 gm, 106 infants were treated prophylactically with a single 5 ml/kg dose of synthetic surfactant and 109 infants were given an equivalent dose of air placebo shortly after birth. In each group, 40 children survived infancy: 36 children in the air placebo group and 30 children in the synthetic surfactant group were available for follow-up. Weight, height, and head circumference measurements were similar for both groups at 1-year adjusted age. Infants who received synthetic surfactant at birth had statistically similar Bayley Scales of Infant Development scores (mental developmental index, 92 vs 83; psychomotor developmental index, 87 vs 82) compared with controls. Mild to moderate impairments in the synthetic surfactant group were 7% versus 29% in the control group; these differences were not statistically significant. The incidence of retinopathy of prematurity, the number of hospital readmissions, the need for surgery after day 28, evidence of chronic lung disease, the need for respiratory support at 1-year adjusted age, and the incidence of allergies were also not different between the two groups. However, the proportion of infants surviving without impairment was modestly higher in the synthetic surfactant group (8%, air placebo group; 23%, synthetic surfactant group). The findings from this small study indicate that infants weighing 500 to 699 gm who receive a single prophylactic dose of synthetic surfactant at birth have neurodevelopmental outcomes at least equivalent to those of infants given air placebo at 1-year follow-up.
To determine the impact of the use of synthetic surfactant on hospital resource use and charges, we analyzed the economic data from a multicenter, randomized, placebo-controlled clinical trial of synthetic surfactant in infants with neonatal respiratory distress syndrome and birth weights between 700 and 1350 gm. Two 5 ml/kg doses of a synthetic surfactant (Exosurf Neonatal) or air placebo were administered to 419 infants who were receiving mechanical ventilation and had an arterial/alveolar oxygen tension ratio < 0.22. In addition to the clinical endpoints for safety and efficacy, data were collected on length of hospital stay, days in the neonatal intensive care unit, days of mechanical ventilation, days of oxygen supplementation, and hospital charges until the infant reached 1 year adjusted age. Growth and development of infants who received synthetic surfactant therapy in the study and survived to 1 year adjusted age were equivalent to those of the survivors in the air placebo group. For 1-year survivors, synthetic surfactant reduced the average length of stay at the different levels of care needed during the hospitalization such as neonatal intensive care unit days, days of mechanical ventilation, and days of oxygen supplementation. For nonsurvivors, synthetic surfactant increased the average length of stay, especially at more intense levels of care. Total hospital charges for the initial hospitalization and through 1 year adjusted age for a hypothetic cohort of 100 infants treated with synthetic surfactant were, on average, the same as those for a comparable cohort of infants in the air placebo group. These results indicate that rescue therapy with synthetic surfactant in infants with respiratory distress syndrome and birth weights from 700 to 1350 gm can result in significantly improved survival without significant increases in hospital charges.
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Eighty-nine low-birthweight, preterm infants were enrolled in a longitudinal study to describe motor development, infantile reactions and postural responses during the first chronological year of life and to determine the relationship between these behaviors. There was a clear trend from prevalence of primitive patterns, such as the asymmetric tonic neck reflex, towards a prevalence of mature postural reactions such as the Landau, righting and protective extension reflexes. Statistical analysis suggested that a relationship exists between infantile patterns, automatic postural reactions and motor development that is similar to that accepted as normal in term infant development, when allowance is made for preterm birth. Correlations were also obtained between integration of the tonic labyrinthine response and the presence of the asymmetric tonic neck pattern at the time of hospital discharge and later achievement of motor milestones. These relationships warrant further investigation.
In an across study analysis of five multicenter, placebo-controlled trials of the synthetic surfactant, Exosurf Neonatal in infants weighing at least 700 gm, the incidence of clinical pulmonary hemorrhage was 1.9% in treated infants and 1.0% in control infants. To investigate whether a similar increase was also present histologically at postmortem examination, a blinded retrospective review of all autopsy reports from infants dying during these five trials was conducted. Pulmonary hemorrhage was present in 55% of 159 infants undergoing autopsy; the incidence was not different in infants treated with surfactant or air placebo. Birth weight was inversely related to the incidence of pulmonary hemorrhage in both groups. Pulmonary pathologic findings significantly associated with pulmonary hemorrhage included pulmonary interstitial emphysema and necrotizing laryngotracheitis in both groups. In the surfactant group, patent ductus arteriosus, intraventricular hemorrhage, and pneumothorax were significantly more frequent among those who developed pulmonary hemorrhage. In contrast to clinical diagnosis, pathologic diagnosis of pulmonary hemorrhage at autopsy was not more common in infants treated with Exosurf Neonatal.
Hypertension in the neonate is commonly related to renal disease. More specifically, renovascular hypertension in neonates is often associated with the placement of a umbilical artery catheter. Many medications, including angiotensin-converting enzyme (ACE) inhibitors, have been used in the treatment of neonatal hypertension. Captopril, an ACE inhibitor, is an oral agent that is effective in renovascular hypertension. We describe the use of intravenous enalapril, another ACE inhibitor, in successfully treating severe renovascular hypertension refractory to standard medical therapy in two term neonates.
1. Diltiazem produced a dose-dependent inhibition of contractions due to norepinephrine (NE), serotonin (5HT) and high potassium depolarization in both coronary and femoral artery rings. 2. Diltiazem was a more potent and efficacious blocker of all 3 agonists in the coronary arteries. 3. Dose response curves to NE and 5HT indicated that diltiazem produced a noncompetitive type of blockade. 4. Diltiazem blocked contractions produced by 5HT more easily than those produced by NE in both coronary and femoral artery rings. 5. That diltiazem was more potent in coronary than femoral arteries suggests a basic difference in calcium regulation in the two vessels.
OBJECTIVE: To determine whether a significant relationship exists between the presence of apnea and the number of days it takes a premature infant to attain full oral feeding. DESIGN: A two-way analysis of variance factorial design (apnea x aminophylline) was used with infants grouped according to presence or absence of apnea and whether they were receiving aminophylline. SETTING: Neonatal intensive-care and step-down nurseries of a level III teaching hospital. PATIENTS/PARTICIPANTS: Eligibility criteria for this study included gestational age of 28-34 weeks, less than 48 hours of mechanical ventilation, and absence of congenital anomalies. Infants were classified into one of four groups: Group 1 (NN) consisted of infants who had no recorded apnea and were not receiving aminophylline (n = 27); group 2 (AA) consisted of infants receiving aminophylline who continued to experience apnea during the transition time to oral feeding, (n = 20); group 3 (NA) consisted of infants receiving aminophylline who did not experience apnea during the transition time to oral feeding (n = 12); and group 4 (AN) were infants who experienced some apnea but never received aminophylline (n = 6). All 65 enrolled subjects completed the study. PROCEDURES: Review of medical records and daily nursing notes to record apnea instances and oral feeding status for each 24-hour period. MAIN OUTCOME MEASURES: The number of days between the first attempted oral feeding and full oral feeding was recorded, as well as number of apnea instances occurring during the transition time. RESULTS: An analysis of variance procedure showed that groups who did not experience apnea had a significantly (F[1, 61] = 10.19, p < .01) shorter transition time (NN = 6.6 days, NA = 5.4 days) than groups who did (AA = 11.3 days, AN = 10.3 days). Apnea was found to be correlated strongly with transition time (R = .42, p < .001). A multiple linear regression forward selection procedure showed apnea to make the greatest contribution to variance in transition time in days with a partial R2 of .18 (p < .001). CONCLUSION: Apnea appears to be a factor that influences the length of time it takes a premature infant to begin receiving full oral feedings.