Robotic injection of zebrafish embryos for high-throughput screening in disease models

The increasing use of zebrafish larvae for biomedical research applications is resulting in versatile models for a variety of human diseases. These models exploit the optical transparency of zebrafish larvae and the availability of a large genetic tool box. Here we present detailed protocols for the robotic injection of zebrafish embryos at very high accuracy with a speed of up to 2000 embryos per hour. These protocols are benchmarked for several applications: (1) the injection of DNA for obtaining transgenic animals, (2) the injection of antisense morpholinos that can be used for gene knock-down, (3) the injection of microbes for studying infectious disease, and (4) the injection of human cancer cells as a model for tumor progression. We show examples of how the injected embryos can be screened at high-throughput level using fluorescence analysis. Our methods open up new avenues for the use of zebrafish larvae for large compound screens in the search for new medicines

Development of an auditory test battery for young children: a pilot study.

Contains fulltext : 58228.pdf (publisher's version ) (Closed access)This article describes the development and results of a pilot study with a recently developed auditory test battery for 4-6-year-old Dutch children. The test battery consisted of a sustained auditory attention (SAA) test, a dichotic words (DW) test, a binaural masking-level difference (BMLD) test, an auditory word discrimination (AWD) test, a gap detection (GD) test and a test of phonemic awareness, the Lindamood Auditory Conceptualization (LAC) test. Our results show that this test battery can be administered successfully to children aged 4 years and older. Most tests showed a clear effect of chronological age; the strongest age effects were found for the DW test and the LAC test. The BMLD test was the only test for which no significant age effect was found in this group of children. A small, but significant right-ear advantage was found on the DW test, for the 4- and the 6-year-olds. Correlations between subtests were in general rather high, suggesting that several tests in this test battery may be tapping into similar auditory abilities

Assessment of auditory processing in 6-year-old language-impaired children.

Contains fulltext : 63068.pdf (publisher's version ) (Closed access)The performance of a group of twenty 6-year-old children with specific language impairment (SLI) on several behavioural auditory tests was compared to that of a group of twenty age-matched control children. The auditory test battery used in this study consisted of the following tests: a speech-in-noise test, a filtered speech test, a binaural fusion test, a frequency pattern test, a duration pattern test, a temporal integration test, an auditory word discrimination test, an auditory synthesis test, an auditory closure test and a number recall test. Our results show that the SLI children obtained scores on almost all tests that were significantly lower than those of the control group. Many of the basic auditory processing measures in our test battery correlated significantly with receptive and language scores, suggesting a (causal) relationship between auditory processing and language proficiency. Results from discriminant function analyses do not warrant deleting one or more tests from the test battery yet (with the exception of the auditory synthesis test and the temporal integration test, for which we did not find significant group effects). At present, we are conducting experiments with older (SLI and control) children and adults to find whether the significant performance deficits of the SLI children are also found in older SLI children, and to determine the influence of maturational effects on these auditory tests

Neutron Stars and Black Holes in X-ray Binaries

Galactic accretion driven stellar X-ray sources can be divided into groups in different ways. An important division, which covers almost all known X-ray binaries, can be made according to the mass of the donor star: high-mass X-ray binaries and low-mass X-ray binaries. Another distinction (partially overlapping with the previous one) can be made on the basis of the nature of the accreting object: a strongly magnetized neutron star, a neutron star with a weak magnetic field, or a black hole. In this review I describe the properties of these different types of X-ray binaries, and discuss the mass determinations which are the basis for distinguishing accreting neutron stars from black holes.Comment: 58 pages, 15 figures. To be published in 'The Many Faces of Neutron Stars', R. Buccheri, J. van Paradijs, M.A. Alpar (Eds), Kluwer Academic Publisher