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Biomedical subjects

A Leviton

Publications and source records attributed to A Leviton.

At least 127 records · Page 7Linked to original sources
PubMed1988

Hemorrhage, phenobarbital, and fluctuating cerebral blood flow velocity in the neonate.

Fifty-one sequential intubated babies with birth weights of less than 1,751 were evaluated by serial Doppler ultrasound during the first three days of life. These babies were part of a phenobarbital prophylaxis trial cohort study. Subependymal-intraventricular hemorrhage developed in 17 of the babies. Infants with subependymal-intraventricular hemorrhage, whether or not they received pancuronium or phenobarbital, had coefficients of variation comparable to those of babies without hemorrhage. Coefficient of variation values of the right were comparable to values obtained from the left anterior cerebral artery complex and did not appear to be consistently altered by the presence of subependymal-intraventricular hemorrhage. Coefficient of variation values appeared to be consistently greatest on day 1 and lowest on day 2. In addition, the values overall increased as the number of waves used to determine the coefficient of variation enlarged from five to 20. This phenomena, however, was not seen among pancuronium recipients and suggests that movement artifact may be a determinant of coefficient of variation values. We conclude that, when the best 20 waves are chosen to evaluate the coefficient of variation, no association exists between coefficient of variation values and development of subependymal-intraventricular hemorrhage or administration of phenobarbital.

Blood Flow Velocity↗
PubMed1988

Arterial blood gas derangements associated with death and intracranial hemorrhage in premature babies.

We evaluated to what extent acidosis and alkalosis and their respiratory and metabolic components during the first 12 hours of life occurred prior to early neonatal death and postnatal intracranial hemorrhage among 206 low birth weight, intubated premature babies participating in a clinical trial of phenobarbital prophylaxis for intracranial hemorrhage. Time-weighted indices included the time each baby spent with abnormal values of pH, PaCO2 and HCO3-. Babies whose birth weight was less than 1 kg suffered adversities associated with prolonged pH less than 7.35. Heavier birth weight babies were at increased risk of adversity if their pH fell below 7.2. Babies who were not severely acidotic initially, but became so within hours, were at prominently increased risk of death and hemorrhage. Babies who had a mild increase of PaCO2 between 45 and 60 mmHg were less likely to develop germinal matrix hemorrhage than their peers who had more severe hypercapnia. A time-weighted measure of metabolic deficit correlated with death, but not with hemorrhage. Prolonged exposure to pH greater than 7.55 was associated with reduced risk of subependymal/intraventricular hemorrhage and death, especially in babies below 1 kg birth weight. We conclude that acidosis is an antecedent of intracranial hemorrhage in low birth weight premature babies, that duration of exposure might convey important risk information, and that birth weight is a correlate of vulnerability to some pH disturbances.

Acidosis↗
PubMed1988

Caffeine consumption and the risk of reproductive hazards.

Recent reports on the relationship between caffeine consumption by pregnant women and their infants' risk of miscarriage, low birth weight, preterm delivery and congenital malformations were reviewed. The evidence continues to support the view that moderate consumption of caffeine by pregnant women does not adversely affect their fetuses.

Abnormalities, Drug-Induced↗
PubMed1988

Bilirubin, intraventricular hemorrhage, and phenobarbital in very low birth weight babies.

The relationships among serum bilirubin concentration on days 5 and 7, birth weight, the presence of intraventricular hemorrhage, and the receipt of phenobarbital were examined in a group of 232 newborns weighing less than 1,751 g who were intubated, mechanically ventilated by 12 hours after birth, and whose parents had given permission for a randomized trial of phenobarbital prophylaxis of intraventricular hemorrhage. The ratio of serum bilirubin concentration to birth weight (the bilirubin divided by birth weight index [BBI]) was used to examine the impact of 25 variables on a clinical guideline for therapy of hyperbilirubinemia in newborn infants. A linear regression model was used; the most powerful covariate was a birth weight less than 1.0 kg. The only other variable that reduced the BBI was phenobarbital receipt. The presence of intraventricular hemorrhage and ecchymoses had a significant influence increasing the BBI.

Bilirubin↗
PubMed1987

Longitudinal analyses of prenatal and postnatal lead exposure and early cognitive development.

In a prospective cohort study of 249 children from birth to two years of age, we assessed the relation between prenatal and postnatal lead exposure and early cognitive development. On the basis of lead levels in umbilical-cord blood, children were assigned to one of three prenatal-exposure groups: low (less than 3 micrograms per deciliter), medium (6 to 7 micrograms per deciliter), or high (greater than or equal to 10 micrograms per deciliter). Development was assessed semiannually, beginning at the age of six months, with use of the Mental Development Index of the Bayley Scales of Infant Development (mean +/- SD, 100 +/- 16). Capillary-blood samples obtained at the same times provided measures of postnatal lead exposure. Regression methods for longitudinal data were used to evaluate the association between infants' lead levels and their development scores after adjustment for potential confounders. At all ages, infants in the high-prenatal-exposure group scored lower than infants in the other two groups. The estimated difference between the overall performance of the low-exposure and high-exposure groups was 4.8 points (95 percent confidence interval, 2.3 to 7.3). Between the medium- and high-exposure groups, the estimated difference was 3.8 points (95 percent confidence interval, 1.3 to 6.3). Scores were not related to infants' postnatal blood lead levels. It appears that the fetus may be adversely affected at blood lead concentrations well below 25 micrograms per deciliter, the level currently defined by the Centers for Disease Control as the highest acceptable level for young children.

Child Development↗
PubMed1987

Migraine and other diseases in women of reproductive age. The influence of smoking on observed associations.

From among the pregnant women in the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, we identified 508 who had migraine, and 3192 who had no history of migraine, of taking headache medication during the previous 12 months, and of headaches during the pregnancy. Migraineurs smoked more heavily and had a longer smoking history than their headache-free peers. Among migraineurs, smokers were not more likely to consume analgesics than nonsmokers. Regardless of smoking classification, more migraineurs consumed tranquilizers, amphetamines, and sleeping pills than headache-free women. Among smokers only, migraine was associated with heart disease, thrombosis/phlebitis, asthma, peptic ulcer, and pneumonia. In nonsmokers, migraine was associated with drug sensitivity and other allergies.

Adolescent↗
PubMed1987

Respiratory complications in low-birth-weight infants who received phenobarbital.

We compared the ventilatory requirements of 127 infants who received phenobarbital for five days with those of 111 infants who received placebo. All infants were intubated, weighted less than 1750 g at birth, and survived the first ten days of life. Those infants who received phenobarbital did not require ventilatory assistance for more days than did placebo receivers. However, a pneumothorax or pulmonary interstitial emphysema was more likely to develop in infants who received phenobarbital than in infants who received placebo, even when adjustment was made for the presence of subependymal-intraventricular hemorrhage. We believe this is the first report of this relationship and recommend additional studies to test the hypothesis that phenobarbital contributes to the occurrence/recognition of pneumothorax or pulmonary interstitial emphysema in very-low-birth-weight infants if phenobarbital continues to be used routinely as prophylaxis or treatment.

Cerebral Hemorrhage↗
PubMed1987

The prophylactic clinical trial as a epidemiologic resource.

We encourage investigators to use data collected in a clinical trial of a prophylactic agent or procedure to study the epidemiology of the disease or event the prophylactic was meant to prevent. Making additional use of previously collected data is economically attractive. Problems can arise, however, if the sample is not representative of the universe of all people at risk of the disorder, the data set is not adequate to the task, or the prophylactic and/or its correlates influence the risk of the disorder. Investigators should consider modifying data collection procedures in future prophylactic trials so that they are suitable for an epidemiologic study. They and readers of their reports, however, are advised to be cautious in drawing inferences from epidemiologic studies extracted from prophylactic trials.

Clinical Trials as Topic↗
PubMed1987

Pregnancy hypertension, blood pressure during labor, and blood lead levels.

Pregnancy hypertension, blood pressure during labor, and the umbilical cord blood lead concentration were assessed in 3851 women for whom additional demographic, medical, and personal information was available. Lead levels correlated with both systolic (Pearson r = 0.081, p = 0.0001) and diastolic (r = 0.051, p = 0.002) blood pressures during labor. The incidence of pregnancy hypertension increased with lead level. Multivariate models of pregnancy hypertension and systolic blood pressure as a function of maternal age, parity, hematocrit, ponderal index, race, and diabetes were improved by including lead as a predictor variable. At these observed levels of exposure (mean blood lead, 6.9 +/- 3.3 [SD] micrograms/dl), lead appears to have a small but demonstrable association with pregnancy hypertension and blood pressure at the time of delivery, but not with preeclampsia.

Adult↗
PubMed1986

Occurrence of elevated protoporphyrin levels in relation to lead burden in infants.

Simultaneous blood lead (PbB), erythrocyte protoporphyrin (EP), and hematocrit measurements were made semiannually in 232 normal infants from 6 to 24 months of age. The PbB averaged 7 (SD = 5) and ranged from 0 to 64 micrograms/dl. The incidence of elevated EP, a marker for deranged heme synthesis, was unrelated to PbB at levels below 15 micrograms/dl but was fourfold greater among the infants with PbB above 15 micrograms/dl. This relationship persisted even after eliminating the 31 (4%) anemic (hematocrit less than 33%) samples. The confounding effects of iron deficiency are discussed.

Child, Preschool↗
PubMed1986

Do learning handicaps and headache cluster?

Children who are brought to medical attention because of frequently recurring or disabling headaches appear to have an increased prevalence of learning handicaps. Some of this increase might reflect Berkson's principle--the selection bias of an overrepresentation of patients with two disorders. Consideration is given to five models that show a relationship between learning handicap and headache. Two of the models are dismissed as too simple. Studies are needed to determine whether learning handicap and headache are indeed associated, and, if so, how. Clinicians are advised not to wait until these studies have been completed before implementing therapeutic programs that might prove helpful to those children with both headache and learning handicap.

Child↗
PubMed1986

In-home versus clinic-based services for the developmentally disabled child: who is the primary client--parent or child?

This paper analyzes two different approaches to service delivery, in-home and clinic-based, in order to assist planners and clinicians in utilizing the merits of both systems most effectively. The two systems are compared and contrasted along the following variables: team process, identified client, pace of treatment, and degree of coverage. Using these variables as a guideline, this paper proposes that the degree to which the family's priorities are similar or dissimilar to the priorities of the organization determines the degree of effectiveness of home-based or clinic-based services. This proposal is discussed and case histories illustrating this premise are presented.

Ambulatory Care Facilities↗
PubMed1986

Childhood brain tumors and paternal occupation in the aerospace industry.

Data from a case-control study of childhood brain tumors were analyzed to examine the possibility that paternal occupation in the aerospace industry is related to the development of a brain tumor in offspring. Parents of 51 children with brain tumors diagnosed in western Washington State during 1978-81 were interviewed, and their responses were compared to those of parents of 142 children selected at random from this population. Among all children, proportions of case and control fathers who had ever been employed in the aerospace industry were nearly identical [relative risk (RR) = 0.94; 95% confidence interval (CI) = 0.40-2.19]. Employment in the aerospace industry during the period from 1 year prior to birth to the time of diagnosis and any employment in the manufacturing part of the industry were not associated with increased risk. However, stratification by age at diagnosis revealed an increased risk associated with father's ever-employment in the industry (RR = 2.10; 95% CI = 0.79-5.60) for children under 10 years old. A corresponding decreased risk (RR = 0.12; 95% CI = 0.01-1.08) was found for children over 10 years old. Because of the relatively small number of cases with a positive paternal occupational history, interpretations of the difference in the direction of the association according to age at diagnosis must remain tentative ones.

Adolescent↗
PubMed1986

Neonatal intracranial hemorrhage and phenobarbital.

We enrolled 280 intubated babies with birth weights of less than 1,751 g in a double-blind randomized prospective clinical trial to evaluate whether phenobarbital influences the likelihood of developing subependymal-intraventricular-intraparenchymal hemorrhage. Phenobarbital was associated with an increased risk of developing any subependymal-intraventricular-intraparenchymal hemorrhage and was not associated with a diminished risk of either severe hemorrhage or germinal matrix hemorrhage. This increased risk was apparent even after we considered the influence of phenobarbital levels, timing of phenobarbital administrations, institutional differences, quality of ultrasound scans, gestational age- and birth weight-specific effects, ascertainment bias, and other possible confounders of phenobarbital administration.

Cerebral Hemorrhage↗
PubMed1986

Correlates of low-level lead exposure in urban children at 2 years of age.

The blood lead levels of a large number of US preschool children approach the value regarded as the upper limit of normal. To reduce the number of children whose levels increase into the range thought to be toxic, the antecedents and correlates of levels in the 0- to 25-micrograms/dL range must be identified. In a large longitudinal study of middle and upper-middle class children living in metropolitan Boston, we evaluated how well five sets of variables predicted children's blood lead levels at 2 years of age: environmental lead sources, mouthing activity, home environment/care giving, prior developmental status, and sociodemographic characteristics. A series of bivariate and multivariate analyses indicated that only environmental lead sources and, to a lesser extent, mouthing activity accounted for significant portions of the variance in blood lead levels. Environmental lead sources were not significantly related to the home environment/care-giving variables or to sociodemographic characteristics. The most promising approach for achieving community-wide reductions in children's blood lead levels is reduction in the amount of lead in the proximate environment.

Analysis of Variance↗