Biomedical subjects
Publications and source records attributed to R Peters.
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Explore the source record for details and available documents.
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Explore the source record for details and available documents.
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The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.
The immune response has largely been implicated in the pathogenesis of inflammatory bowel disease (ulcerative colitis and Crohn's disease) and immunoglobulin A nephropathy. We present a 26-year-old woman with a long past history of asymptomatic macroscopic hematuria who later developed several episodes of bloody stools and abdominal pain. A colonic biopsy disclosed ulcerative colitis and a renal biopsy was consistent with immunoglobulin A nephropathy. Immunoglobulin A nephropathy is the most common glomerulonephritis, being end-stage renal disease a rare but the most serious complication. It can be primary or secondary, but the association between both entities is unusually observed. We discuss the possible immunologic mechanisms involved and believe the initial immunologic derangement originates in the bone marrow. We suggest both conditions must be considered when either a patient with ulcerative colitis and micro- or macrohematuria or with renal involvement and a past history of diarrhea or abdominal pain presents.
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This paper discusses issues related to the development of plans to improve the effectiveness of mental health services for urban First Nations people. The discussion focuses on emerging issues related to health care reform and regionalization. While it is impossible to make specific recommendations without reference to local conditions, developing an awareness of the general issues involved will help in the process of identifying the principles and approaches needed to frame local solutions.
Comparative pharmacological and toxicological studies were carried out on animals covering the preparation d,1-oxyphedrine (myophedrine), put out in the GDR, as against the drug 1-oxyphedrine. The activity of both drugs showed no material difference. Clinical trials demonstrated good tolerance of the drug both by healthy persons and patients with its intravenous administration twice a day in amounts of 1 mg, or by mouth--3 times a day in amounts of 8--16 mg. In outpatients with anginal pains after sustained myocardial infarction and also in institutionally treated patients with myocardial infarction the activity of d,1-oxyphedrine proved to be not inferior to that of 1-oxyphedrine.
Paroxysmal supraventricular tachycardia can usually be managed without any specific therapy or with an appropriate drug program. Some patients, however, are resistant to conventional therapy. In the past decade, the electrophysiologic pathogenic mechanisms of this rhythm disorder have been elucidated, and this, coupled with progress in intracardiac instrumentation, has enabled the physician to induce specific rhythm disorders and to map them to determine an ideal, specially tailored method of treatment. As a result, the use of radiofrequency pacing and surgery are becoming increasingly important in the treatment of patients with paroxysmal supraventricular tachycardia, especially those with arrhythmias related to Wolff-Parkinson-White syndrome.