Fetoscopic myelomeningocoele closure: Is the scientific evidence enough to challenge the gold standard for prenatal surgery?

Since the completion of the Management of Myelomeningocoele Study, maternal-fetal surgery for spina bifida has become a valid option for expecting parents. More recently, multiple groups are exploring a minimally invasive approach and recent outcomes have addressed many of the initial concerns with this approach. Based on a previously published framework, we attempt to delineate the developmental stage of the surgical techniques. Furthermore, we discuss the barriers of performing randomized controlled trials comparing two surgical interventions and suggest that data collection through registries is an alternative method to gather high-grade evidence.     

Early life history of tropical Anguilla leptocephali in the western Pacific Ocean

In order to examine the early life-history characteristics of tropical eels, otolith microstructure and microchemistry were examined in leptocephali of Anguilla bicolor pacifica (27.6-54.1 mm TL, n=20) and A. marmorata (22.0-47.3 mm TL, n=8) collected during a cruise in the western Pacific. A. bicolor pacifica occurred between 10°N and 15°N in the west and between 5°S and 10°N farther to the east. A. marmorata also occurred in two different latitudinal ranges in the Northern (15-16°N) and Southern Hemispheres (3-15°S) of the western Pacific. The increment widths in the otoliths of these leptocephali increased between the hatch check (0 days) and about an age of 30 days in both species, and then gradually decreased toward the otolith edge. Otolith Sr:Ca ratios showed a gradual increase from the otolith center to the edge. The ages of A. bicolor pacifica and A. marmorata leptocephali ranged from 40 to 128 days and from 38 to 99 days, respectively. Growth rates of A. bicolor pacifica and A. marmorata leptocephali ranged from 0.33 to 0.71 mm day^-1 and from 0.45 to 0.63 mm day^-1, respectively. These leptocephali had estimated growth rates that were spread out throughout most of the reported range of growth rates of the leptocephali of the temperate species, the Japanese eel and the Atlantic eels. Differences in the spatial distribution in relation to current systems, and the age and size compositions of the leptocephali of A. bicolor pacifica and A. marmorata suggested different spawning locations for these two species.     

Environmental hypoxia and haemocyanin between-individual variability in Norway lobsters Nephrops norvegicus (L.)

The extent to which exposure to environmental hypoxia (PO₂=8, 6, and 4 kPa, approximately 40%, 30%, and 20% saturation, respectively) resulted in an increase in the concentration of the respiratory pigment haemocyanin ([Hc]) in individuals of the Norway lobster Nephrops norvegicus depended crucially on the initial [Hc] as well as the intensity of the hypoxia itself. While mean [Hc] did increase with decreasing PO₂ (and the variation decreased), for individuals with relatively high initial [Hc] there was no change or even a decrease observed. The greatest hypoxia-related increases in [Hc] were observed in the individuals with the lowest initial [Hc]. Consequently the notion of an 'optimum' [Hc] for a given level of oxygenation was postulated. The changes in [Hc] recorded took place over a considerably shorter time scale (hours rather than days) than has been observed in previous studies. It was not possible to correlate environmental PO₂ and median [Hc] in the field. However, it was interesting that the [Hc] frequency distribution curve for lobsters collected from a site that had been markedly hypoxic (PO₂=8.0 kPa, approximately 40% saturation) until a few days before sampling was almost exactly the same shape (i.e. leptokurtic) and position (i.e. similar median) to that obtained when lobsters were exposed to PO₂=8.0 kPa in the laboratory. Although it would have been desirable to investigate the effect of hypoxia on the frequency distribution of a physiological trait, in this case [Hc], it was not possible due to insufficient sample size, even though the sample sizes employed were considerably larger than those normally used in physiological investigations.     

Trail and recruitment pheromones in Camponotus socius (Hymenoptera: Formicidae)

Summary. Worker ants of Camponotus socius employ multicomponent signals during group recruitment to food sources and nest emigrations. The chemical signals consist of trail orientation pheromones that originate from the hindgut. Two components that elicit trail orientation behavior were identified: (2S,4R,5S)-2,4-dimethyl-5-hexanolide and 2,3-dihydro-3,5-dihydroxy-6-methylpyran-4-one. Although both compounds release trail following behavior, in choice tests the former compound is preferred significantly. The major recruitment signal appears to be formic acid discharged from the poison gland. Compounds identified in the Dufour gland secretions do not seem to be involved in the recruitment process.     

Spray mechanism of crepidogastrine bombardier beetles (Carabidae; Crepidogastrini)

Summary.   The defensive glandular apparatus of primitive bombardier beetles of the tribe Crepidogastrini (Carabidae) is described for the first time. As exemplified by two African species (Crepidogaster ambreana and C. atrata), the apparatus conforms to the basic bombardier plan, in that the glands are bicompartmented and the secretion is quinonoid (it contains 1,4-benzoquinones and hydrocarbons), hot, and discharged audibly. In a number of morphological respects the crepidogastrine apparatus resembles that of the classical bombardiers of the tribe Brachinini (rather than that of bombardiers of the paussoid lineage), reinforcing the view, already held on taxonomic grounds, that the Crepidogastrini and Brachinini are closely related. That the Crepidogastrini may be primitive relative to Brachinini is underscored by the finding that, unlike brachinines, crepidogastrines do not pulse their secretory emissions. Moreover, they discharge their secretion as a mist, rather than forcibly in the form of jets. Received 22 May 2001; accepted 29 May 2001.