Three-dimensional rendering of otolith growth using phase contrast synchrotron tomography.

A three-dimensional computer reconstruction of a plaice Pleuronectes platessa otolith is presented from data acquired by the Diamond Light synchrotron, beamline I12, X-ray source, a high energy (53-150 keV) source particularly well suited to the study of dense objects. The data allowed non-destructive rendering of otolith structure, and for the first time allows otolith annuli (internal ring structures) to be analysed in X-ray tomographic images.

Levels of interpopulation differentiation among different functional classes of immunologically important genes.

It has been postulated that gene function may influence the degree to which allele frequencies differ among populations. In order to evaluate this effect, genotypic data from resequencing studies of genes classified as cytokines, cytokine receptors, cell adhesion molecules, Toll-like receptors and coagulation proteins were analysed for genetic differentiation (FST) between population samples of European and African descent. FST values did not differ statistically among functional groups when all polymorphic sites were included in the analyses. However, analysis based on nonsynonymous SNPs alone suggested weak heterogeneity among functional classes (P=0.0424). Particularly high levels of differentiation were shown by individual nonsynonymous SNPs at some genes, most notably ICAM1 and some Toll-like receptors. These genes interact directly with pathogens, and may therefore have been subject to geographically localised natural selection. Such loci warrant particular attention in studies of genetic disease risk and local adaptation to environmental conditions.

Predictors of neonatal mortality in 1,500-1,999 g premature infants with respiratory failure. Basis for ECMO Therapeutic Trial.

Despite the introduction of new ventilation techniques and surfactant therapy, some premature infants still experience severe respiratory failure and either die or survive with severe bronchopulmonary dysplasia. Extracorporeal membrane oxygenation is currently not offered for preterm infants with a birth weight less than 2,000 g, mainly because of the potential high risk for intracranial hemorrhage. The aim of this study was to determine risk predictors for mortality alone and for mortality or major lung morbidity in 1,500-1,999 g premature infants with respiratory failure. We reviewed the medical records of all preterm infants (n = 459) with respiratory failure and a birth weight of 1,500-1,999 g treated at five medical centers from 1989 to 1991. Of those infants, 23 (5%) had severe respiratory failure, defined as a requirement for ventilatory support with the fraction of inspired oxygen > or = 0.8 or peak inspiratory pressure > or = 30 cmH2O for > or = 3 hr in the 1st week of life. A mortality of > or = 75% was associated with a single arterial/alveolar oxygen ratio < or = 0.04; pulmonary air leak alone or pulmonary air leak with a mean airway pressure > or = 12 cmH2O; and arterial oxygen tension < or = 50 mmHg. These risk predictors may provide a basis for the selection of patients for future clinical trials of extracorporeal membrane oxygenation in this high-risk group of 1,500-1,999 g premature infants with severe respiratory failure.

A ten-year retrospective study of pink and yellow neonatal hyaline membrane disease.

Since it was first described several years ago, yellow bilirubin staining of the pulmonary membranes in neonatal hyaline membrane disease has apparently become more common. In a retrospective study of neonatal autopsy experience, it was found that as more of the premature infants survived longer, yellow hyaline membrane disease was a more frequent finding, increasing from 7% of all newborns having hyaline membrane disease at autopsy in 1970 to 50% in 1980. In comparing 499 cases with eosinophilic hyaline membranes with 168 cases of yellow membranes, newborns with bilirubin staining of the pulmonary membranes were found to be more premature (P less than .02), had smaller autopsy weight (P less than .002), and survived longer (P less than .00001). When multiple clinical parameters were compared between a group of infants with yellow membranes and a group of infants with pink membranes who were matched for gestational age, year of birth, and length of survival, no differences were found between the two groups. No correlation was found between kernicterus and yellow staining of the pulmonary hyaline membranes in the first years of the study, but there was a strong correlation in the last 5 years, coincident with the increase in the rate of yellow hyaline membrane disease found at autopsy. The gross bilirubin staining of the brain was the secondary type of kernicterus, not toxic bilirubin encephalopathy. The observation of bilirubin staining in the lung and in the brain correlates with prolonged survival in some very small premature infants. This does not appear to be a manifestation of bilirubin toxicity, but rather a marker of prior tissue damage.

Natural Enterovirus and Fecal Coliform Contamination of Gulf Coast Oysters.

The numbers of fecal coliforms and enteroviruses present in oysters and/or their growing waters of two Mississippi reefs were determined over a 12-month period. Bacterial and viral levels reflected the classification of the waters at each location as set by the Mississippi State Board of Health in compliance with the National Shellfish Sanitation Program, but statistically significant correlations between these levels were not observed. Twelve viral isolates were found at an approved oyster harvesting location, eight of which were identified as poliovirus type 1. At the prohibited site, 146 viruses were isolated including poliovirus types 1 and 2, echovirus type 24 and several isolates which remain to be identified. The number of virus isolates from samples from each location represented approximately 35% of the number of plaques observed; however, no consistent ratio of plaque to confirmed virus was demonstrated. The results suggest that the fecal coliform levels in oyster growing waters do not reflect the level of virus contaminaton in either approved or prohibited waters.