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Biomedical subjects

A Burrows

Publications and source records attributed to A Burrows.

At least 19 recordsLinked to original sources
PubMed2000

Supernova explosions in the Universe.

During the lifetime of our Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen we breathe, the iron in our cars, the calcium in our bones and the silicon in the rocks beneath our feet. These exploding stars also influence the birth of new stars and are the source of the energetic cosmic rays that irradiate us on the Earth. The prodigious amount of energy (approximately 10(51), or approximately 2.5 x 10(28) megatonnes of TNT equivalent) and momentum associated with each supernova may even have helped to shape galaxies as they formed in the early Universe. Supernovae are now being used to measure the geometry of the Universe, and have recently been implicated in the decades-old mystery of the origin of the gamma-ray bursts. Together with major conceptual advances in our theoretical understanding of supernovae, these developments have made supernovae the centre of attention in astrophysics.

Astronomical Phenomena↗
PubMed1999

Comparison of intradermal testing and serum testing for allergen-specific IgE using monoclonal IgE antibodies in 84 atopic dogs.

OBJECTIVE: To compare an ELISA measuring serum allergen-specific IgE with intradermal skin testing in canine atopic dermatitis. PROCEDURE: Eighty-four dogs with the clinical diagnosis of atopic dermatitis underwent intradermal skin testing and serum testing for allergen-specific IgE. Tests were performed in a blinded fashion. Positive reactions were compared and the sensitivity and specificity of the serum test (using intradermal skin test as the standard) were determined overall and for individual allergen groups (grass pollens, weed pollens, tree pollens, house dust mites and fleas). RESULTS: The sensitivity of the ELISA overall was 90.4%. Evaluating the individual allergen groups, the sensitivity for dust mite hypersensitivity was 95.1%, for fleas 85.4%, for tree pollens 84.3%, for grass pollens 95.1% and for weed pollens 96.4%. The specificity was 91.6% overall, for dust mites 96.3%, for fleas 92.7%, for tree pollens 95.2%, for grass pollens 94% and for weed pollens 80.7%. CONCLUSION: The evaluated ELISA seemed reliable for the diagnosis of atopy in practice and can be recommended as a screening test prior to intradermal skin testing or for use in dogs when immunotherapy is not a therapeutic option.

Animals↗
PubMed1997

The PACE program.

Explore the source record for details and available documents.

Health Expenditures↗
PubMed1996

Atmospheric, evolutionary, and spectral models of the brown dwarf Gliese 229 B.

Theoretical spectra and evolutionary models that span the giant planet-brown dwarf continuum have been computed based on the recent discovery of the brown dwarf Gliese 229 B. A flux enhancement in the 4- to 5-micrometer wavelength window is a universal feature from jovian planets to brown dwarfs. Model results confirm the existence of methane and water in the spectrum of Gliese 229 B and indicate that its mass is 30 to 55 jovian masses. Although these calculations focus on Gliese 229 B, they are also meant to guide future searches for extrasolar giant planets and brown dwarfs.

Astronomical Phenomena↗
PubMed1996

Regression pattern of beta human chorionic gonadotrophin in blood after chemotherapy for gestational trophoblastic neoplasia.

Although beta human chorionic gonadotrophin (beta-HCG) is a clinically-useful tumour marker in gestational trophoblastic neoplasia, there is limited information on how serum beta HCG regresses in molar pregnancy and choriocarcinoma during chemotherapy. The study included 41 patients who had been treated by single- and multidrug regimens, and decay curves for regression of beta HCG in the circulation in these patients were fitted to the data. Thirty-three patients achieved a biochemical remission ('cured') by first-line chemotherapy; this gave an overall efficacy rate of 80%. The beta HCG decay curves convey useful information of the chemosensitivity of the tumour, and may assist in determining the time required for treatment and earlier change in treatment for the chemoresistant tumour.

Adolescent↗
PubMed1995

Open-loop and closed-loop postural control mechanisms in Parkinson's disease: increased mediolateral activity during quiet standing.

Stabilogram-diffusion analysis was used to gain insights into how idiopathic Parkinson's disease (IPD) affects the postural control mechanisms involved in maintaining erect stance. Twenty-two subjects with IPD and twenty-four healthy elderly subjects were studied under eyes-open, quiet-standing conditions. The postural control mechanisms in the parkinsonian subjects, compared to the healthy elderly, were characterized by an increase in the effective stochastic activity in the mediolateral direction. Mediolateral posturographic measures were also associated with a history of falls and poor performance on clinical measures of balance. It is hypothesized that the increase in mediolateral activity in subjects with IPD may reflect an attempt to maintain potentially stabilizing movements during quiet standing in the face of impaired movement in the anteroposterior direction. This study supports the notion that mediolateral instability is an important posturographic marker of functional balance impairment in the elderly.

Aged↗
PubMed1995

Age-related changes in open-loop and closed-loop postural control mechanisms.

In an earlier posturographic investigation (Collins and De Luca 1993) it was proposed that open-loop and closed-loop control mechanisms are involved in the regulation of undisturbed, upright stance. In this study, stabilogram-diffusion analysis was used to examine how the natural aging process affects the operational characteristics of these control mechanisms. Stabilogram-diffusion analysis leads to the extraction of repeatable center-of-pressure (COP) parameters that can be directly related to the steady-state behavior and functional interaction of the neuromuscular mechanisms underlying the maintenance of erect posture. Twenty-five healthy young males (aged 19-30 years) and twenty-five elderly males (aged 71-80 years) who were free of major gait and postural disorders were included in the study. An instrumented force platform was used to measure the time-varying displacements of the COP under each subject's feet during quiet standing. The COP trajectories were analyzed as one-dimensional and two-dimensional random walks, according to stabilogram-diffusion analysis. Using this technique, it was demonstrated cross-sectionally that healthy aging is associated with significant changes in the 'quasi-static' dynamics of the postural control system. (It was also shown that more traditional posturographic analyses, i.e., summary statistics, were not sensitive enough to detect these age-related differences.) It was found that the steady-state behavior of the open-loop postural control mechanisms in the elderly is more positively correlated and therefore perhaps more unstable, i.e., the output of the overall system has a greater tendency to move or drift away from a relative equilibrium point over the short term. In contrast with this result, it was also found that the steady-state behavior of the closed-loop postural control mechanisms in the elderly is more negatively correlated and therefore perhaps more stable, i.e., over the longer term, there is an increased probability that movements away from a relative equilibrium point will be offset by corrective adjustments back towards the equilibrium position. In addition, it was demonstrated that the elderly utilize open-loop control schemes for longer time intervals and correspondingly larger COP displacements during periods of undisturbed stance. This result suggests that in the elderly there is a greater delay, on average, before closed-loop feedback mechanisms are called into play. Finally, it was shown that there is an increased heterogeneity of postural control abilities in healthy older adults.

Adult↗
PubMed1995

The amniotic fluid embolism syndrome: 10 years' experience at a major teaching hospital.

A review of the syndrome of amniotic fluid embolism (AFE) was carried out over a 10 year period, 1984-1993, at the Royal Women's Hospital, Brisbane. There were 9 patients with AFE, of whom 2 died--this gave an incidence of fatal AFE of 3.37 per 100,000 pregnancies at the hospital, in comparison with an incidence of 1.03 per 100,000 pregnancies over a 27-year period in Australia. The study revealed no identifiable risk factors in the characteristics of the patient or her baby, labour and delivery. Three of the patients did not undergo labour and in 4 of the 6 who did, the duration was less than 12 hours. The AFE syndrome could present before, during or after delivery; the common features were shock and respiratory distress, with coagulopathy occurring in 5 patients. Current views of predisposing factors, pathogenesis, diagnosis and management are discussed.

Adult↗
PubMed1993

Choroid plexus cysts in the fetal brain.

Choroid plexus cysts may be detected in the fetal choroid plexus on routine second trimester ultrasound scanning. The presence of these cysts is associated with trisomy 18 (Edward syndrome) in 3.47% of cases and with trisomy 21 (Down syndrome) in 0.46% of cases. The cysts themselves almost always disappear by 23 weeks and are thought to be a normal developmental variant. The world literature experience would indicate that the size of the choroid plexus cyst and the presence of bilateral cysts has no bearing on the magnitude of risk of chromosomal abnormality; 76% of babies with trisomy 18 also have other dysmorphic features which may be detectable by ultrasound. It is strongly advised that genetic counselling be undertaken and amniocentesis be considered when choroid plexus cysts are identified in the fetus.

Adult↗