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Biomedical subjects

W Bray

Publications and source records attributed to W Bray.

8 recordsLinked to original sources
PubMed1998

The period gene controls courtship song cycles in Drosophila melanogaster.

We developed a technique that assists in objective identification of pulse and sine components in the Drosophila melanogaster courtship song. The song was recorded digitally and subjected to wavelet analysis, which decomposed the signal into a series of bands of decreasing frequency in which acoustic power appeared as a function of time. This time-frequency analysis expresses characteristic 'fingerprints' of the pulses, which appear in all frequency bands, and characteristic 'fingerprints' of the sine song, which appear only in the band containing its frequency. Means of the interpulse intervals (IPIs) for each second of 10-min recordings of song in which pulse singing occurred constituted an irregularly sampled time series, intractable to common spectral analysis techniques. Therefore, we took the discrete Fourier transform of this series, which retained all the spectral information in the Fourier coefficients, and used the inverse Fourier transform of these coefficients to yield a new series that was regularly spaced, with an estimate of IPI for each second in the interval. We observed an IPI period of 67.9 s in wild type, 31.1 s in per0, 45.9 s in pers, and 72.0 s in perL. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1997

How cancer gene testing can benefit patients.

A revolution has taken place in the past few decades in our understanding of the genetic origins of human cancer. In particular, genes implicated in inherited susceptibility to forms of cancer are increasingly being identified and their mutations characterized. Many of these genes are also involved in sporadic tumours of the same type, as well as additional tumour types. Understanding of these genes will therefore affect an even greater number of patients.

Bioethics↗
PubMed1995

Effect of transpulmonary pressure on airway closure in immature and mature rabbits.

The transpulmonary pressures (Ptp values) at which airway closure occurred during maximal stimulation with methacholine were compared in 10 mature and 9 immature rabbit lungs by using an alveolar capsule technique to assess airway closure. After maximal constriction, airway opening and alveolar capsule pressures were recorded during small volume oscillations as Ptp was lowered from 12 to 4 cmH2O. At each Ptp, the proportion of alveolar capsules indicating airway closure was greater for the immature than for the mature lungs (P < 0.025). At Ptp of 4 cmH2O, only 20% of alveolar capsules indicated airway closure in the mature lungs in contrast to 85% indicating closure in the immature lungs (P < 0.001). The in vitro sensitivity of tracheal smooth muscle to acetylcholine and histamine was greater in tissues from immature than from mature rabbits. We conclude that the more frequent airway closure observed in immature rabbits could reflect maturational differences in the structure of the bronchi or lung parenchyma or differences in the coupling between the parenchyma and the airways.

Acetylcholine↗
PubMed1984

Excess ventilation with oxygen-powered resuscitators.

Massive subcutaneous emphysema developed in three patients following ventilation with an oxygen-powered, positive pressure resuscitator used by an urban emergency medical service. A faulty valve regulator was identified as the source of the problem. Following this discovery, an extensive field test of all oxygen-powered resuscitators used by the emergency service was carried out. Sixty resuscitators were tested, 15 of which (25%) were found to be deficient on at least one of the test criteria. It is strongly recommended that all personnel using these devices be trained to recognize equipment malfunction and that periodic performance evaluations be carried out on all such equipment. The results of this field test, and other performance tests done previously, raise questions about the use of positive pressure resuscitators in the emergency setting.

Aged↗