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Biomedical subjects

P C Myers

Publications and source records attributed to P C Myers.

9 recordsLinked to original sources
PubMed2001

Endophthalmitis in the western Sydney region: a case-control study.

BACKGROUND: A retrospective case-control study was conducted to investigate risk factors for endophthalmitis following routine intraocular surgery. METHODS: A review was performed of consecutive cases of endophthalmitis from three teaching hospitals in the western Sydney region and matched controls from the same institutions between 1996 and 1998. RESULTS: There were 31 cases and 66 controls. Eighty procedures were phacoemulsification, 15 conventional extracapsular cataract extraction, and two were penetrating keratoplasties. Of the 80 patients who had phacoemulsification surgery, 50 had a clear corneal incision, and 26 had a scleral incision (four were unknown). Logistic regression showed an increased risk of endophthalmitis with surgical complications (P = 0.002) and clear cornea temporal incisions (P = 0.007). Risk of endophthalmitis was reduced with use of subconjunctival injections (P = 0.008). The yield for the Gram stain was 47% and for culture was 67%. Anterior chamber tap in addition to vitreous biopsy alone did not increase the yield for microorganism (P = 0.78). Mean visual acuity on presentation was hand movement with 13 patients (50%) showing visual improvement following intravitreal injections of antibiotics (P = 0.003). Visual prognosis did not correlate with presenting visual acuity but appeared to be better in those who grew Staphylococcus epidermidis or were culture negative. CONCLUSIONS: Although this study is unable to draw definite conclusions regarding risk of endophthalmitis in clear corneal temporal cataract surgery, sufficient data suggest the importance of incision type and location. Surgical complication is an important risk factor for endophthalmitis. Use of subconjunctival antibiotic injections at the conclusion of the procedure is recommended.

Aged↗
PubMed1997

A nurse practitioner as the first point of contact for urgent medical problems in a general practice setting.

OBJECTIVES: The aim of this study was to examine the suitability of nurse practitioners for assessing and managing urgent clinical problems presenting in primary care. METHODS: Patients registered at a suburban group practice presenting with acute medical problems were offered the choice of seeing a GP or a nurse practitioner. The outcomes of 1000 consultations were analysed by recording the repeat consultation rate, the prescription-issue rate and the rate of referral to secondary care, as well as investigating patient satisfaction and the number of dysfunctional consultations and misdiagnoses. RESULTS: Patients reported a high level of satisfaction with nurse practitioner consultations, and there were no recorded instances of medical sequelae due to poor diagnosis or mismanagement. Nurse and doctors saw patients with similar age and sex distributions, but the results suggested that there was a significant difference between the morbidity of problems seen. There was also a difference in the outcomes of repeat consultation rate and the prescription issue rate, although there was little difference in the rate of referral for secondary care. CONCLUSION: As patients expressed a high level of satisfaction with the nurse practitioner, this suggests that given the choice, patients in primary care can safely and effectively 'self triage' themselves between GPs and nurse practitioners.

Family Practice↗
PubMed1987

Carotid intraplaque hemorrhage: the significance of neovascularity.

Renewed interest in the neovascularity of atherosclerotic plaques has followed the work of Imparato et al., which confirmed the importance of carotid intraplaque hemorrhage in the production of symptomatic extracranial vascular disease. We have studied the detailed histology of 91 carotid atheromatous plaques with particular regard to hemorrhage and neovascularity and have confirmed the findings of earlier investigators while observing degenerative changes (not previously reported) in these new vessels. The possible role of systemic hypertension in intraplaque hemorrhage and the acceleration of the atherosclerotic process is discussed.

Arteriosclerosis↗
PubMed1980

Microwave thermography in the detection of breast cancer.

Microwave thermography, a method of sensing subcutaneous temperatures, was used in a breast cancer detection study of about 5,000 female patients. The data were taken at wavelengths of 9.1 and 23 cm. Microwave thermography at 23 cm has true-positive and true-negative detection rates of 0.8 and 0.6, respectively, comparable to those of infrared thermography (0.7) and inferior to those of xeromammography (0.9). However, a potential advantage results if microwave and infrared thermography are used together for screening, and if mammography is used only for follow-up on those patients who were positive on either the microwave or the infrared thermograms. It is then possible to obtain true-positive and true-negative detection rates of 0.9 and 0.9, respectively, while only half the number of patients need be subjected to x-rays.

Breast Neoplasms↗
PubMed1979

Microwave thermography: principles, methods and clinical applications.

We review the physical principles, method of operation, measurement limitations, and potential medical applications of microwave thermography. We present detailed results of a study of breast cancer detection at 1.3 and 3.3 GHz, including the dependence of detection rates on microwave frequency, time, tumor depth, and tumor size. At 1.3 GHz, microwave thermography detects breast cancer as well as infrared thermography (true-positive rate = 0.76 when true-negative rate = 0.63). When the two methods are combined, the true-positive rate increases by about 0.1 over that of either method alone.

Breast Neoplasms↗
PubMed1975

Subcutaneous temperatures: a method of noninvasive sensing.

A new method of noninvasive sensing of the subsurface temperature distribution in human and animal tissue is described. Thermal radiation emitted from subsurface depths of several centimeters can be detected with microwave receivers. Temperature sensitivity of order 0.1 degree C and spatial resolution of approximately 1 by 2 centimeters have been obtained. Measurements demonstrating the technique, with feline and human tissue, are reported. A potential medical application is the detection of subsurface thermal anomalies such as malignant tumors and regions of vascular insufficiency.

Animals↗
PubMed1975

Microwave thermography: a method of detecting subsurface thermal patterns.

A discussion has been given of the principles and techniques of microwave thermography. The method is analogous to infrared thermography in that it detects thermal radiation emitted by the body. It differs in that it is sensitive to temperatures several centimeters beneath the skin surface and has coarser spatial resolution. Results are shown of successful attempts to detect subsurface thermal gradients in feline and human tissue. Planned clinical evaluation is described.

Animals↗