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Michael Evans

Publications and source records attributed to Michael Evans.

12 recordsLinked to original sources
PubMed2005

The safety and usefulness of high-dose-rate endoluminal brachytherapy as a boost in the treatment of patients with esophageal cancer with external beam radiation with or without chemotherapy.

PURPOSE: This study reports the results of a single-institution experience with high-dose-rate brachytherapy (HDRBT) used as a boost in the treatment of esophageal cancer with external beam radiation therapy (ERT) with or without chemotherapy. METHODS AND MATERIALS: Patients without evidence of metastatic disease were identified. HDRBT was given before ERT with a dose of 20 Gy in 5 fractions. Patients with a Karnofsky performance of more than 70 received treatment with 50 Gy in 25 fractions and concurrent 5-fluorouracil and cis-platinum during Weeks 1 and 5, whereas patients with a Karnofsky performance of less than 70 were treated with radiation therapy alone with 35 Gy in 14 fractions. RESULTS: Fifty-three patients received HDRBT treatment with combined ERT and chemotherapy and 17 patients with ERT alone. The incidence of acute bone marrow toxicity was 55% Grade 2 and 15% Grade 3, and 85% of patients had Grade 2 esophagitis. With a median follow-up time of 26 months, the median survival was 21 months; the 2-year local recurrence was 25%, and the 5-year survival rate was 28%. CONCLUSION: HDRBT is safe and beneficial for local control in the radical treatment of patients with esophageal cancer.

Adenocarcinoma↗
PubMed2005

Gene-environment interaction effects on the development of immune responses in the 1st year of life.

Asthma is a common disease that results from both genetic and environmental risk factors. Children attending day care in the 1st year of life have lower risks for developing asthma, although the mechanism for this "day care" effect is largely unknown. We investigated the interactions between day care exposure in the 1st 6 mo of life and genotypes for 72 polymorphisms at 45 candidate loci and their effects on cytokine response profiles and on the development of atopic phenotypes in the 1st year of life in the Childhood Onset of Asthma (COAST) cohort of children. Six interactions (at four polymorphisms in three loci) with "day care" that had an effect on early-life immune phenotypes were significant at P<.001. The estimated false-discovery rate was 33%, indicating that an estimated four P values correspond to true associations. Moreover, the "day care" effect at some loci was accounted for by the increased number of viral infections among COAST children attending day care, whereas interactions at other loci were independent of the number of viral infections, indicating the presence of additional risk factors associated with day care environment. This study identified significant gene-environment interactions influencing the early patterning of the immune system and the subsequent development of asthma and highlights the importance of considering environmental risk factors in genetic analyses.

Asthma↗
PubMed2005

Anthroposophic vs. conventional therapy of acute respiratory and ear infections: a prospective outcomes study.

CONTEXT: Acute respiratory and ear symptoms are frequently treated with antibiotics. Anthroposophic treatment of these symptoms relies primarily on anthroposophic medications. OBJECTIVE: To compare anthroposophic treatment to conventional treatment of acute respiratory and ear symptoms regarding clinical outcome, medication use and safety, and patient satisfaction. DESIGN: Prospective, non-randomised comparison of outcomes in patients self-selected to anthroposophic or conventional therapy under real-world conditions. SETTING: 29 primary care practices in Austria, Germany, Netherlands, UK, and USA. PARTICIPANTS AND THERAPY: 1016 consecutive outpatients aged > or = 1 month, consulting an anthroposophic (n = 715 A-patients) or conventional physician (n = 301 C-patients) with a chief complaint of acute (< or = 7 days) sore throat, ear pain, sinus pain, runny nose or cough. Patients were treated according to the physician's discretion. PRIMARY OUTCOME: Patients' self-report of treatment outcome (complete recovery/major improvement/slight to moderate improvement/no change/deterioration) at Day 14. RESULTS: Most common chief complaints were cough (39.9% of A-patients vs. 33.9% of C-patients, p = 0.0772), sore throat (26.3% vs. 23.3%, p=0.3436), and ear pain (20.0% vs. 18.9%, p=0.7302). Baseline chief complaint severity was severe or very severe in 60.5% of A-patients and 53.3% of C-patients (p=0.0444), mean severity (0-4) of complaint-related symptoms was 1.3 +/- 0.7 vs. 1.2 +/- 0.6 (p=0.5197). During the 28-day follow-up antibiotics were prescribed to 5.5% of A-patients and 33.6% of C-patients (p<0.0001), anthroposophic medicines were prescribed to all A-patients and no C-patient. OUTCOMES: Improvement within 24 hours occurred in 30.9% (221/715) of A-patients and 16.6% (50/301) of C-patients (p<0.0001), improvement within 3 days in 73.1% and 57.1% (p<0.0001). At Day 7 complete recovery or major improvement was reported by 77.1% of A-patients and 66.1% of C-patients (p=0.0004), at Day 14 by 89.7% and 84.4% (p=0.0198). Complete recovery rates at Day 7 were 30.5% and 23.3% (p<0.0001); at Day 14 they were 64.2% and 49.5% (p<0.0001). 69.9% of A-patients and 60.5% of C-patients were very satisfied with their physician (p=0.0043); 95.7% and 83.4% would choose the same therapy again for their chief complaint (p<0.0001). After adjustment for country, gender, age, chief complaint, duration of complaint, previous episode of complaint within last year, and baseline symptom severity, odds ratios favoured the A-group for all these outcomes. Adverse drug reactions were reported in 2.7% of A-patients and 6.0% of C-patients (p=0.0157). CONCLUSION: Compared to conventional treatment, anthroposophic treatment of primary care patients with acute respiratory and ear symptoms had more favourable outcomes, lower antibiotic prescription rates, less adverse drug reactions, and higher patient satisfaction.

Acute Disease↗
PubMed2005

High-dose-rate endorectal brachytherapy in the treatment of locally advanced rectal carcinoma: technical aspects.

PURPOSE: In this era of new radiation technologies and tumor imaging, a high-dose-rate endorectal brachytherapy has been developed and tested in a phase I/II study of advanced rectal tumors. In this article, we report technical aspects of the treatment modality. METHODS AND MATERIALS: Forty-nine patients underwent staging with endoscopic endorectal ultrasound, and the tumor dimensions were determined with MRI of the pelvis. Patients with resectable rectal cancer (staged T2, T3, or early T4) were treated with preoperative high-dose-rate endorectal brachytherapy followed by surgery 6-8 weeks later. Under direct rectoscopy, radio-opaque clips were used to mark the tumor margins. The treatment planning was done with the use of a CT simulator, and the treatment was delivered using a flexible endorectal applicator with eight catheters arranged around the circumference of the applicator and a high-dose-rate brachytherapy remote afterloading system with an Iridium-192 source. Isodose distributions were generated by the Plato planning system (Nucletron B.V., Veenendaal, The Netherlands) and digitally reconstructed radiographs were used as references for daily treatment. A tumor dose of 26 Gy in four fractions was prescribed, and intramesorectal deposits were documented on the magnetic resonance images. RESULTS: Forty-nine patients received planned treatment, and all but 2 patients underwent planned surgery. The pathology specimens showed a complete macroscopic response in 64% of the patients and tumor downstaging in 67% of the patients. CONCLUSIONS: Advances in tumor imaging and 3D treatment planning systems allow for better tumor mapping and dose planning. The use of a multichannel flexible endorectal applicator leads to tumor downstaging before surgery in patients with resectable locally advanced rectal carcinomas. The technique used in our center was practical and validated by this study.

Brachytherapy↗
PubMed2005

Absorbed dose to water reference dosimetry using solid phantoms in the context of absorbed-dose protocols.

For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Such a framework is useful when there is a desire to put dose measurements using solid phantoms on an absolute basis. Putting solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We introduce a phantom dose conversion factor that converts a measurement made in a solid phantom and analyzed using an absorbed dose calibration protocol into absorbed dose to water under reference conditions. We provide techniques to measure and calculate the dose transfer from solid phantom to water. For an Exradin A12 ionization chamber, we measured and calculated the phantom dose conversion factor for six Solid Water phantoms and for a single Lucite phantom for photon energies between 60Co and 18 MV photons. For Solid Water of certified grade, the difference between measured and calculated factors varied between 0.0% and 0.7% with the average dose conversion factor being low by 0.4% compared with the calculation whereas for Lucite, the agreement was within 0.2% for the one phantom examined. The composition of commercial plastic phantoms and their homogeneity may not always be reproducible and consistent with assumed composition. By comparing measured and calculated phantom conversion factors, our work provides methods to verify the consistency of a given plastic for the purpose of clinical reference dosimetry.

Algorithms↗
PubMed2005

Flu shot.

Explore the source record for details and available documents.

Adolescent↗
PubMed2004

Using administrative data to measure ambulatory mental health service provision in primary care.

OBJECTIVE: We sought to determine the accuracy of administrative data for identifying mental health service provision in primary care. STUDY DESIGN: This was a chart abstraction study measuring agreement between billing data and clinical data on the binary variable "mental health visit." Data were collected from the charts and billing records of 5 academic family practice clinics in Toronto, Ontario (1999 to 2000). Billing claims (n = 952) were selected from the billings for all visits by a stratified random sampling technique. A blinded data abstractor reviewed the clinical charts and assigned diagnostic codes for each patient visit associated with the selected claims. Any visit with at least 1 abstracted mental health diagnostic code was defined as a mental health visit. The test characteristics of 4 administrative measures of mental health service provision, based on different combinations of billing codes, were calculated. RESULTS: The accuracy of the administrative data was 86.8% when compared with clinical data. The sensitivity of the 4 administrative measures ranged from 22.3% to 80.7%. The specificity ranged from 97.0% to 99.5%. CONCLUSIONS: This is the first study to establish the performance of administrative data in measuring mental health service provision in a primary care setting. In our setting, broadly defined administrative measures of mental health have excellent specificity and adequate sensitivity for exploring and understanding mental health service utilization.

Adult↗
PubMed2003

Cassini imaging of Jupiter's atmosphere, satellites, and rings.

The Cassini Imaging Science Subsystem acquired about 26,000 images of the Jupiter system as the spacecraft encountered the giant planet en route to Saturn. We report findings on Jupiter's zonal winds, convective storms, low-latitude upper troposphere, polar stratosphere, and northern aurora. We also describe previously unseen emissions arising from Io and Europa in eclipse, a giant volcanic plume over Io's north pole, disk-resolved images of the satellite Himalia, circumstantial evidence for a causal relation between the satellites Metis and Adrastea and the main jovian ring, and information on the nature of the ring particles.

Journal Article↗
PubMed2003

Touch sensitivity in plants: be aware or beware.

A recent paper shows that touch sensing and gravity sensing interact to guide roots around obstacles. Upon encountering an object, the touch stimulus induces curvature behind the root tip and partially suppresses the gravity response, enabling the root to navigate around the obstacle while maintaining contact with it. These findings raise questions regarding the nature of touch sensing in roots, the location of the sensors, and the manner in which these sensory systems interact to accomplish obstacle avoidance.

Arabidopsis↗
PubMed2002

The impact of empirical management of acute cystitis on unnecessary antibiotic use.

BACKGROUND: Guidelines for the management of acute cystitis support empirical antibiotic treatment; however, up to half of symptomatic women have negative urine cultures. OBJECTIVE: To determine whether empirical treatment leads to unnecessary antibiotic prescriptions in women with symptoms of acute cystitis. METHODS: A cohort of 231 women (defined as females aged 16 years and older) presenting to family physicians' offices with symptoms of cystitis underwent a standardized clinical assessment, urine dip testing, and culture. Recommendations for urine testing and antibiotic treatment under 3 empirical strategies were compared with observed physician management and a logistic regression model for the outcomes of antibiotic prescriptions, urine culture testing, and unnecessary antibiotics, defined as a prescription where the subsequent urine culture was negative. RESULTS: There were 123 positive urine cultures (53.3%). Physicians prescribed antibiotics to 186 women (80.9%), of whom 74 (39.8%) were culture negative. Unnecessary antibiotic use was similar for 2 guidelines recommending empirical antibiotic treatment without testing for pyuria (41.4% and 40.6%). Treating women with classic cystitis symptoms and pyuria would have decreased unnecessary antibiotic use (26.2%; P =.02) but resulted in fewer women with confirmed urinary tract infection receiving immediate antibiotics (66.4% vs 91.8% usual care; P<.001). A derived prediction model incorporating testing for pyuria and nitrites would also have reduced unnecessary antibiotic use (27.5%; P =.03), but more women with confirmed urinary tract infection would have received immediate antibiotics (81.3%; P =.01). CONCLUSIONS: Empirical antibiotic treatment of acute cystitis in women without testing for pyuria promotes unnecessary antibiotic use. A simple decision rule provides for prompt treatment of infected women while reducing antibiotic overuse and unnecessary urine testing.

Acute Disease↗