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Biomedical subjects

Alan Leviton

Publications and source records attributed to Alan Leviton.

27 records · Page 2Linked to original sources
PubMed2003

Antenatal mycoplasma infection, the fetal inflammatory response and cerebral white matter damage in very-low-birthweight infants.

We address the question as to whether Ureaplasma urealyticum or Mycoplasma hominis, cultured from the placenta of very-low-birthweight (VLBW) infants, are associated with an increased risk of (a) fetal vasculitis and (b) ultrasonographic cerebral white matter echolucency. The sample consisted of 464 VLBW infants for whom (i) the surface of the chorion was cultured for U. urealyticum and M. hominis; (ii) the placenta was examined histologically; and (iii) a cranial ultrasound scan was obtained close to days 1, 7 or 21. Infants with echolucency were compared with controls in univariable and stratified analyses and in multivariable logistic regressions. Fifty-three per cent of placentas from infants with fetal vasculitis harboured U. urealyticum compared with 18% of controls (P </= 0.001). M. hominis was present in 14% of cases of fetal vasculitis and in 2% of controls (P </= 0.001). Among cases of echolucency, 22% had U. urealyticum compared with 30% of controls (P = 0.33), whereas 17% of these cases and 5% of controls had M. hominis (P = 0.08). Our findings support the hypothesis that U. urealyticum in the placenta of VLBW infants contributes to the fetal inflammatory response without contributing to white matter damage. Our finding that M. hominis in the placenta was associated with a not quite significant threefold risk increase for echolucency deserves further investigation.

Brain↗
PubMed2003

Prolonged latency after preterm premature rupture of membranes: an evaluation of histologic condition and intracranial ultrasonic abnormality in the neonate born at <28 weeks of gestation.

OBJECTIVE: The purpose of this study was to evaluate whether infants who were delivered at <28 weeks of gestation after prolonged latency in pregnancies that were complicated by preterm premature rupture of membranes are at increased risk of histologic chorioamnionitis and intracranial ultrasound abnormalities. STUDY DESIGN: A retrospective cohort analysis of 430 singleton infants born at <28 weeks of gestation in five hospitals (January 1991 through December 1993) with at least one of three protocol cranial scans read by a consensus committee and with placental pathologic evidence. Outcome variables were placental (histologic chorioamnionitis, fetal vasculitis) and neonatal (intraventricular hemorrhage, echolucencies, ventriculomegaly). Latency was divided into five intervals, and outcomes in the longer four intervals were compared with those in infants who were delivered at <1 hour after membrane rupture. Each outcome-latency relationship was evaluated in a logistic model that was controlled for confounders. RESULTS: Odds ratios and CIs for each latency interval that was controlled for confounders that included gestational age, maternal race, antenatal steroid and antibiotic administration, and delivery mode show a statistically significant increase in the risk of histologic chorioamnionitis and fetal vasculitis. Models for intraventricular hemorrhage, ventriculomegaly, and echolucencies failed to demonstrate significant differences with increasing latency. CONCLUSIONS: Ascending transcervical infection after preterm premature rupture of membranes is documented by the increasing odds ratios of placental inflammation. The odds of ultrasonically detectable brain abnormalities, however, did not increase with increasing latency.

Adult↗
PubMed2002

Clinical and survival covariates of eight classes of childhood supratentorial neuroglial tumors.

BACKGROUND: In the current study, the authors investigated clinical, surgical, and histologic characteristics (covariates) and their interactions in eight previously identified classes of childhood supratentorial neuroglial tumors. The classes resulted from 5 factor score profiles on 703 supratentorial neuroglial tumors in the Childhood Brain Tumor Consortium database. METHODS: The Cox proportional models were used to identify class survival covariates. RESULTS: Age was found to be a survival covariate only in Class 1, in which older age increased the 5-year survival rate 73% from the first year (0.49) to the tenth year (0.85). A greater amount of tumor removed improved survival in Classes 2 and 4 only. Rosenthal fibers improved survival in Class 2 and overrode the negative effects of high Proliferative factor scores and pleomorphic nuclei. Survival for Class 3 children with high Proliferative factor scores improved from 0.60 to 0.95 as the Spongy factor scores increased. Survival in Class 4 increased from 0.17 to 0.39 with total tumor removal. Irregular nuclei and glomeruloid capillaries improved survival in Class 5 patients. Class 6 survival improved with low cell density. Macrocysts in tumors in Classes 1 and 5 were found to improve survival. CONCLUSIONS: As a result of the current study, the authors conclude that survival covariates differ with tumor class and may modify prognosis considerably.

Astrocytoma↗
PubMed2002

Perinatal infection, fetal inflammatory response, white matter damage, and cognitive limitations in children born preterm.

Only sparse information is available about a possible association between antenatal infection outside the brain and subsequent cognitive limitations among preterm infants. Based on published studies, we provide a theoretical schema that links them via the fetal inflammatory response and neonatal white matter damage. We conclude that the relationship between antenatal infection and cognitive limitations deserves much further attention by researchers interested in the prevention of this undesirable outcome of prematurity.

Acute-Phase Reaction↗
PubMed2002

Methodologic issues in epidemiologic studies of congenital microcephaly.

In this methodological paper, we explore a number of issues that pose problems for those who seek the antecedents of congenital microcephaly. We pay particular attention to three concerns: Who is a case? How should cases be classified? To whom should cases be compared?

Epidemiologic Methods↗
PubMed2002

Systemic hypotension and white-matter damage in preterm infants.

This study was designed to test the hypothesis that systemic hypotension during the first postnatal week increases the risk of ultrasonographic echolucency in the white matter of preterm infants (< or = 28 weeks' gestation) while adjusting for confounders. From a study base of 1607 very-low-birthweight neonates (500 to 1500 g), a subsample of 243 preterm infants (122 females; < or = 28 weeks' gestation) was selected for echolucency and data collection prospectively for the entire first postnatal week. Data analyses were performed separately for the first 24 hours of life, for the interval from the end of the first 24 hours to the end of the fourth postnatal day, and for days 5, 6, and 7. Systemic hypotension was defined as the mean arterial blood pressure in the lowest quartile for the infant's week of gestational age. Protocol cranial ultrasounds were those obtained closest to days 1, 7, and 21. A committee of sonologists classified the infants as having either echolucency (echolucency group) or not (control group). Systemic hypotension during the first week of life appeared to be associated with echolucency in univariable analyses but the association did not persist after adjustment for potential confounders. Detailed summaries of 13 previous studies, the majority of which did not show an association between systemic hypotension and white-matter damage, are presented. In sum, these results do not support the hypothesis that systemic hypotension contributes to echolucency among preterm infants.

Brain↗
PubMed2002

Risk of cranial ultrasound abnormalities in very-low-birth-weight infants conceived with assisted reproductive techniques.

OBJECTIVE: To evaluate risks of cranial ultrasound abnormalities among very-low-birth-weight (VLBW) infants conceived with fertility therapy (ovulation induction only or with assisted reproductive techniques [ART]) and of multiple gestation pregnancies. STUDY DESIGN: The incidences of cranial ultrasound abnormalities in 1473 VLBW infants conceived with and without fertility therapy and born of multiple versus singleton pregnancies were compared, using logistic regression models. RESULTS: Infants conceived with ART were less likely to have intraventricular hemorrhage (IVH). Twins and triplets had risks of cranial ultrasound abnormalities similar to those of singletons. Twins and triplets conceived with ART were at lower risk of IVH. CONCLUSION: VLBW infants conceived with ART do not appear to be at increased risk of cranial ultrasound abnormalities. Likewise, twins and triplets were not at increased risk of these abnormalities.

Brain Damage, Chronic↗
PubMed2002

Chorioamnionitis, mechanical ventilation, and postnatal sepsis as modulators of chronic lung disease in preterm infants.

OBJECTIVE: This case-control study of chronic lung disease (CLD) evaluated the hypothesis that chorioamnionitis promotes CLD and interacts with other risk factors for CLD, including mechanical ventilation and postnatal infection. STUDY DESIGN: We identified a population of 193 infants who met our case criteria for CLD whose birth weights were 7 days and culture-documented sepsis. In multivariable analyses, infants were at greatest risk for CLD when they had exposure to both chorioamnionitis and either mechanical ventilation >7 days (odds ratio, 3.2; 95% confidence interval, 0.9-11) or postnatal infection (odds ratio, 2.9; 95% confidence interval, 1.1-7.4). CONCLUSIONS: We conclude that prolonged mechanical ventilation or postnatal infection increases the risk of CLD among surviving preterm infants and that these 2 factors interact with antenatal infection to further increase the risk of CLD.

Case-Control Studies↗