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Biomedical subjects

M Joy

Publications and source records attributed to M Joy.

At least 19 recordsLinked to original sources
PubMed2001

Rothia dentocariosa endocarditis complicated by multiple intracranial hemorrhages.

Rothia dentocariosa is a gram-positive rod found commonly as part of the normal flora of the mouth. It rarely causes clinical disease. Subacute infective endocarditis has been the most commonly reported R dentocariosa infection, and extracardiac complications occur frequently. Solitary intracranial hemorrhages have been reported in two cases. We describe the first case of infective endocarditis complicated by the sequential and unusually prolonged development of multiple new intracranial hemorrhages.

Actinomyces↗
PubMed2000

Laboratory detection of X-ray fringes with a grazing-incidence interferometer

Starting with Galileo's observations of the Solar System, improvements of an order of magnitude in either the sensitivity or resolution of astronomical instruments have always brought revolutionary discoveries. The X-ray band of the spectrum, where exotic objects can have extremely high surface brightness, is ideally suited for significant improvements in imaging, but progress has been impeded by a lack of optics of sufficiently high sensitivity and quality. Here we present an X-ray interferometer design that is practical for adaptation to astronomical observatories. Our prototype interferometer, having just under one millimetre of baseline, creates fringes at 1.25 keV with an angular resolution of 100 milliarcseconds. With a larger version in orbit it will be possible to resolve X-ray sources at 10(-7) arcseconds, three orders of magnitude better than the finest-resolution images ever achieved on the sky (in the radio part of the spectrum) and over one million times better than the current best X-ray images. With such resolutions, we can study the environments of pulsars, resolve and then model relativistic blast waves, image material falling into a black hole, watch the physical formation of astrophysical jets, and study the dynamos of stellar coronae.

Journal Article↗
PubMed2000

Results concerning the absolute stability of delayed neural networks.

We report on results concerning the global asymptotic stability (GAS) and absolute stability (ABST) of delay models of continuous-time neural networks. These results present sufficient conditions for GAS and in case the network has instantaneous signalling as well as delay signalling (for example, a delayed cellular neural network (DCNN)), are milder than previously known criteria; they apply to neural networks with a broad range of activation functions assuming neither differentiability nor strict monotonicity. We are therefore able to interpret the results as guarantees of absolute stability of the network with respect to the wide class of admissible activation functions. Furthermore, these results do not assume symmetry of the connection matrices. We also present a sufficient condition for absolute stability in the presence of nonconstant delays.

Neural Networks, Computer↗
PubMed1999

Introduction and summary of principal conclusions of the Second European Workshop in Aviation Cardiology.

Aviation is the only system of mass transportation regulated by international statute. The responsible agency is the International Civil Aviation Organization (ICAO), a safety directorate of the United Nations Organization. In 1995 almost 1-3 billion passengers were carried by the airlines of the world, the previous decade having seen a 50% growth in the number of passengers and the amount of freight carried. The total complement of professional pilots world-wide is approximately 455,000, although a significantly greater number of licence holders are involved in private or recreational flying. Approximately 11,500 large commercial transport aircraft are in service. All nations are signatories to the Chicago Convention of 1944, which, with its Annexes, forms the legal basis for an international agreement on aviation safety. Chapter six of Annex I contains the 'International Standards and Recommended Practices' (ISARPs) for the medical licensing of personnel which have been adopted and revised from time to time by the ICAO. The standards are interpreted by the relevant chapter in the Manual of Civil Aviation Medicine, first published in 1974 and last revised 18 years ago. Its status is only advisory, and it is currently being rewritten. As a part of the European harmonization process, the Joint Airworthiness Authorities directorate (now the Joint Aviation Authorities (JAA)) was set up as a supranational European body to agree explicit standards for the 29 signatory nations, and to regulate all aspects of certification. The new medical standard, which is complementary to that of the ICAO, is due to be promulgated in July 1999 whilst the cardiological standard, which has already undergone comprehensive revision, has yet to be agreed. Hafner has reviewed the JAA process in this supplement.

Accidents, Aviation↗
PubMed1998

Death in the home: the doctor's responsibility.

The role physicians assume when patients die at home is nebulous and ill defined. Beyond the traditional function of providing comfort and condolence to family members, the physician's duties are directed toward how our society deals with the bureaucratic and legal aspects of death. Statistics are maintained regarding the numbers of deaths in municipalities and states and the causes of death, and those numbers are used by individuals and organizations for a multitude of legal, medical, and political purposes. The state also has an obvious interest in uncovering and prosecuting crime. The physician has a vital part to play in providing essential medical information for those record-keeping, statistical, and legal purposes. Physicians need to be mindful of the important functions being served when they are asked to complete death certificates and to report cases and provide information to the medical examiner. As with many other physician activities, the information we provide about our patients' deaths serves a singular societal need; thus, we should view that function not as a burden but as a vital aspect of the enriching and enobling work that is uniquely ours.

Aged↗
PubMed1997

Multicenter comparative study of the efficacy and safety of sotalol in the prophylactic treatment of patients with paroxysmal supraventricular tachyarrhythmias.

We performed a randomized, double-blind, placebo-controled, parallel-group comparison study of the efficacy and safety of sotalol in the prophylaxis of paroxysmal supraventricular tachyarrhythmias (PSVTs) (including paroxysmal atrial fibrillation and paroxysmal reentrant SVTs). The frequency of PSVT episodes while not receiving drug therapy was monitored during a baseline phase, the length of which depended on the frequency of PSVT events. In the double-blind phase, the duration of which depended on the baseline frequency of episodes of PSVT, patients received placebo, sotalol 80 mg twice daily, or sotalol 160 mg twice daily. PSVT events were documented by electrocardiogram and diary. The time to recurrence of PSVT was significantly less compared with placebo when receiving sotalol 80 mg (p = 0.018) and sotalol 160 mg (p = 0.0009). On subanalysis, sotalol was shown to be effective in the prophylaxis of both paroxysmal atrial fibrillation and paroxysmal reentrant arrhythmias. Sotalol was well tolerated, with no deaths, proarrhythmia, or cardiac failure. Because of adverse effects, drug therapy was discontinued in six patients.

Adult↗
PubMed1992

Need for invasive cardiological assessment and intervention: a ten year review.

The uptake of invasive cardiological investigation and cardiopulmonary bypass procedures by the North West Surrey Health District was audited over the years 1979-88. Growth was almost continuous throughout the ten year period. The need within the district each year for coronary angiography seemed to be between 111 and 171 and for surgical revascularisation of the myocardium between 63 and 96 procedures; the first figure is the mean of the second quinquennial period (1984-88) and the second figure the total for 1988. After correction for the standardised mortality ratio and catchment area, the national requirement should lie between 690 and 1070 coronary angiograms and 390 and 600 coronary artery bypass graft operations per million population each year. There is a further national requirement for 70 valvar heart operations and 30 miscellaneous procedures per million population each year. Owing to delays in the provision of services, 20 patients died of a cardiovascular cause while they were on the waiting list for investigation or surgery. In the United Kingdom the annual target to be achieved by 1990 was 300 coronary artery bypass procedures per million population.

Adult↗