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Biomedical subjects

J Galvin

Publications and source records attributed to J Galvin.

33 records · Page 2Linked to original sources
PubMed1991

Three-dimensional photon treatment planning for Hodgkin's disease.

A multi-institutional study was undertaken using computerized planning systems to develop three-dimensional (3-D) radiotherapy plans for Hodgkin's disease (H.D.). Two patients, the first afflicted with bulky stage II disease and another one with early stage I H.D., were studied. Three main categories of plan were produced for each patient: a) a traditional plan which modelled a conventional mantle treatment on the 3-D system, b) a 3-D standard plan where anterior and posterior fields were designed to cover 3-D target volumes, and c) a 3-D unconstrained plan where innovational techniques were employed. Three-dimensional planning provides information about the dose distribution throughout the large volume irradiated in patients with H.D. that is not available with conventional mantle planning. The use of 3-D techniques resulted in improved tumor coverage, but by allowing for uncertainties such as motion, the doses to normal tissues tended to be higher. The use of unorthodox beam arrangements introduced added complexities, and further increased the lung doses. The most even dose distributions were obtained by incorporating compensating filters into anterior fields. Clinicians showed wide variations in their assessment of the plans, possible reasons for which are addressed in this paper. In addition, calculated probabilities from models of tumor control and normal tissue damage are also presented.

Hodgkin Disease↗
PubMed1991

Three-dimensional treatment planning for lung cancer.

The experience of four institutions involved in a three-dimensional treatment planning contract (NCI) for lung cancer is described. It was found that three-dimensional treatment planning has a significant potential for optimization of treatment plans for radiotherapy of lung cancer both for tumor coverage and sparing of critical normal tissues within the complex anatomy of the human thorax. Evaluation tools, such as dose-volume histograms, and three-dimensional isodose displays, such as multiple plane views, surface dose displays, etc., were found to be extremely valuable in evaluation and comparison of these complex plans. It is anticipated that with further developments in three-dimensional simulation and treatment delivery systems, major progress towards uncomplicated local regional control of lung cancer may be forthcoming.

Humans↗
PubMed1988

Effects of awake tidal breathing, swallowing, nasal breathing, oral breathing and the Müller and Valsalva maneuvers on the dimensions of the upper airway. Evaluation by ultrafast computerized tomography.

Determinations of the size and dynamics of the upper airway during respiration are important in individuals with sleep-related breathing disorders. Ultrafast computerized tomography can acquire eight 8-mm axial-slice thicknesses of the upper airway in 224 ms. If this sequence is acquired every 0.7 second over an entire respiratory cycle and played back in movie mode, the dynamic changes in the airway's size can be evaluated and measured. This report defines the size of the upper airway during normal tidal breathing and describes the changes that occur with swallowing, isolated nasal breathing, and isolated oral breathing and with the Müller and Valsalva maneuvers.

Adult↗
PubMedDate not supplied

Lipid profile, haemostatic variables and angiographically-defined coronary artery disease: a cross-sectional study in an Irish population.

More than 300 risk factors for coronary artery disease (CAD) have been described. There are important geographical and racial differences in both the prevalence of CAD and of potential risk factors. The purpose of this study was to determine the relationship between both the presence and extent of angiographically defined CAD in an Irish population and a spectrum of clinical risk factors, lipid profile and haemostatic variables. On univariate analysis, age, male gender, history of smoking, history of hypertension, total cholesterol, triglycerides, LDL, Cholesterol, the LDL:HDL ratio, apoprotein B-100 and the apoprotein B-100: A-II ratio were associated with the presence of CAD. However, in multivariate analysis only age, male gender, a history of smoking and the apoprotein B-100: A-II ratio remained significantly associated with the presence of CAD. These same risk factors and apoprotein B-100 were significantly associated with the extent of CAD on multivariate analysis. In addition, apoprotein B-100 levels appeared to be associated with disease extent. When all significant variables associated with the presence or extent of CAD were analysed together in a multivariate model, they only accounted for 28% of the variability in the distribution of CAD. Thus, advancing age, male gender, cigarette smoking and apoprotein B-100 appear to be important correlates of the presence and extent of CAD in this selected population. However, in individual patients most of the variability in the distribution of occlusive CAD remains unexplained.

Adult↗
PubMedDate not supplied

Keeping possum.

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

Antiarrhythmic drug therapy in patients with renal failure, liver failure, and congestive heart failure.

Commonly prescribed antiarrhythmic agents--and several recently developed agents--are reviewed with respect to their use in patients with renal failure, hepatic failure, and congestive heart failure. Because removal of electrophysiologically active agents from the systemic circulation in most cases depends on either renal elimination, hepatic metabolism, or both, patients with preexisting kidney or liver disease may be at increased risk of treatment-related drug toxicity, including proarrhythmia. These susceptibilities should be anticipated, with drug selection and/or dosage modified accordingly. Patients with left ventricular dysfunction and heart failure also are at increased risk of treatment-related complications, including proarrhythmia and hemodynamic intolerance. In addition, the metabolism of antiarrhythmic drugs may be impaired in these patients. Preference should be given to drugs with a proven safety profile, such as amiodarone, in patients with heart failure.

Anti-Arrhythmia Agents↗
PubMedDate not supplied

Initial experience with percutaneous balloon mitral commissurotomy.

Percutaneous Transvenous Mitral Commissurotomy (PTMC) is an alternative to surgical mitral valvuloplasty for treatment of selected patients with rheumatic mitral stenosis. We report our initial experience with the technique in 10 patients. The procedure was successful in all patients. There were no major complications. Mitral valve area increased from a mean (+/- SD) of 0.95 +/- 0.2 to 2.18 +/- 0.8 cm2. Transmitral pressure gradient fell from 12 +/- 8 to 4 +/- 5 mmHg while New York Heart Association functional class improved by 1 grade or more in all patients. PTMC is a safe and cost effective alternative to surgical mitral valvotomy in appropriately selected cases.

Aged↗
PubMedDate not supplied

Risks of long-term oral anticoagulation in a non-trial medical environment.

Randomised controlled trials have shown that anticoagulation with warfarin reduces the risk of stroke in patients with atrial fibrillation by two thirds. However there is concern as to whether the rate of anticoagulant-related haemorrhage seen in these trials would be reproduced in a non-trial setting. Four hundred and ten consecutive patients attending a special anticoagulation clinic over one year were asked to complete a questionnaire concerning their warfarin treatment. The total number of years on warfarin was 2870. Of the 410 patients, 59 (14%) admitted to 88 bleeding episodes while on warfarin. Of these bleeding problems, 36/88 (41%) required admission to hospital or to casualty for treatment and 52/88 (59%) required only a lowering or temporary cessation of warfarin therapy. The calculated annual non-fatal bleeding rate of 3% in this survey is identical to that reported from the Copenhagen AFASAK trial. Similarly the 1.3% annual rate of major bleeding requiring attendance at hospital is identical to that in the Stroke Prevention in Non-Rheumatic Atrial Fibrillation trial. The results of this study suggest that oral anticoagulation is as safe in an ordinary medical setting as in a closely supervised trial setting.

Anticoagulants↗