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Biomedical subjects

A Coates

Publications and source records attributed to A Coates.

At least 19 recordsLinked to original sources
PubMed2005

Deep Impact: observations from a worldwide Earth-based campaign.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Cosmic Dust↗
PubMed2004

Solar wind-induced atmospheric erosion at Mars: first results from ASPERA-3 on Mars Express.

The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the martian topside atmosphere to solar wind plasma forcing. The low-altitude penetration of solar wind plasma and the energization of ionospheric plasma may be due to solar wind irregularities or perturbations, to magnetic anomalies at Mars, or both.

Journal Article↗
PubMed2004

Effect of Mycobacterium tuberculosis chaperonins on bronchial eosinophilia and hyper-responsiveness in a murine model of allergic inflammation.

BACKGROUND: Epidemiological evidence suggests that infection with Mycobacterium tuberculosis protects children against asthma. Several laboratories have shown that, in mouse models of allergic inflammation, administration of the whole live tuberculosis vaccine, Mycobacterium bovis bacillus Calmette-Guerin (BCG), prevents ovalbumin (OVA)-induced pulmonary eosinophilia. OBJECTIVE: The aim of this study was to characterize specific M. tuberculosis molecules that are known to modulate immune responses to see if they affected pulmonary eosinophilia and bronchial hyper-responsiveness. METHODS: C57Bl/6 mice were sensitized to OVA on days 0 and 7 and subsequently challenged with OVA on day 14 over a 3-day period. Pulmonary eosinophilia and bronchial hyper-responsiveness were measured 24 h following the last antigen challenge. In some groups, mice were pre-treated with M. tuberculosis or M. tuberculosis chaperonins (Cpns)60.1, 60.2 and 10, and the effect of this treatment on the allergic inflammatory response to aerosolized OVA was established. RESULTS: We show that M. tuberculosis Cpns inhibit allergen-induced pulmonary eosinophilia in the mouse. Of the three Cpns produced by M. tuberculosis, Cpn60.1, Cpn10 and Cpn60.2, the first two are effective in preventing eosinophilia when administered by the intra-tracheal route. Furthermore, the increase in airways sensitivity to inhaled methacholine following OVA challenge of immunized mice was suppressed following treatment with Cpn60.1. The allergic inflammatory response was also characterized by an increase in Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, which was also suppressed following treatment with Cpn60.1. CONCLUSION: These data show that bacterial Cpns can suppress eosinophil recruitment and bronchial hyper-responsiveness in a murine model of allergic inflammation.

Animals↗
PubMed2003

Cystic fibrosis presenting as kwashiorkor in a Sri Lankan infant.

Growth failure is a common presentation of patients with pancreatic insufficient cystic fibrosis. However, full blown kwashiorkor is extremely rare. Cystic fibrosis is also considered to be rare in the South Asian population. This report describes a Sri Lankan infant with cystic fibrosis who presented with clinical features of severe kwashiorkor.

Cystic Fibrosis↗
PubMed2002

First results from the International Breast Cancer Intervention Study (IBIS-I): a randomised prevention trial.

BACKGROUND: Three clinical trials on the use of tamoxifen to prevent breast cancer have reported mixed results. The overall evidence supports a reduction in the risk of breast cancer, but whether this benefit outweighs the risks and side-effects associated with tamoxifen is unclear. METHODS: We undertook a double-blind placebo-controlled randomised trial of tamoxifen, 20 mg/day for 5 years, in 7152 women aged 35-70 years, who were at increased risk of breast cancer. The primary outcome measure was the frequency of breast cancer (including ductal carcinoma in situ). Analyses were by intention to treat after exclusion of 13 women found to have breast cancer at baseline mammography. FINDINGS: After median follow-up of 50 months (IQR 32-67), 69 breast cancers had been diagnosed in 3578 women in the tamoxifen group and 101 in 3566 in the placebo group (risk reduction 32% [95% CI 8-50]; p=0.013). Age, degree of risk, and use of hormone-replacement therapy did not affect the reduction. Endometrial cancer was non-significantly increased (11 vs 5; p=0.2) and thromboembolic events were significantly increased with tamoxifen (43 vs 17; odds ratio 2.5 [1.5-4.4], p=0.001), particularly after surgery. There was a significant excess of deaths from all causes in the tamoxifen group (25 vs 11, p=0.028). INTERPRETATION: Prophylactic tamoxifen reduces the risk of breast cancer by about a third. Temporary cessation of tamoxifen should be considered and the use of appropriate antithrombotic measures is recommended during and after major surgery or periods of immobilisation. Prophylactic use of tamoxifen is contraindicated in women at high risk of thromboembolic disease. The combined evidence indicates that mortality from non-breast-cancer causes is not increased by tamoxifen. The overall risk to benefit ratio for the use of tamoxifen in prevention is still unclear, and continued follow-up of the current trials is essential.

Adult↗
PubMed2001

A snapshot of waiting times for cancer surgery provided by surgeons affiliated with regional cancer centres in Ontario.

BACKGROUND: There is evidence that delays in treatment result in increased psychosocial morbidity for patients diagnosed with cancer. We evaluated waiting times for care among cancer patients treated by surgeons affiliated with regional cancer centres in Ontario. METHODS: Dates for 5 key events related to the surgical management of a patient with cancer were collected by a convenience sample of surgeons who treat breast, gynecologic, colorectal, head and neck, thoracic and urologic cancers. The key events were initial referral, first surgical visit, main treatment decision, major surgery and receipt of postoperative pathology report. The surgeons were also asked to judge the appropriateness of the waiting times for the intervals studied and to identify factors associated with inappropriate delays. RESULTS: A total of 62 surgeons affiliated with 8 regional cancer centres participated; data were collected for 1456 patients who underwent assessment and whose surgical visit occurred between Jan. 31 and May 31, 2000. The median waiting time from referral to first visit was 11.0 days, from first visit to treatment decision 0.0 days, from treatment decision to surgery 20.0 days and from surgery to receipt of the pathology report 8.0 days. The median waiting times for the 2 summary intervals (referral to surgery and referral to receipt of the pathology report) were 37.0 and 48.0 days respectively. The waiting times varied by cancer type; for example, the median time from referral to surgery varied from 29.0 days for colorectal cancers to 64.0 days for urologic cancers. The same interval varied from 19.0 to 43.0 days by treatment centre. The waiting times did not vary substantially by patient age. The surgeons judged that 344 (37.2%) of the 925 patients with dates for the referral-to-surgery interval had inappropriately long waiting times. They indicated that contributing factors to these inappropriate waits were shortage of operating room time (in 181 cases), lack of other resources such as diagnostic tests or allied health personnel (in 156) and patient preference or circumstance (in 28) (factors were not mutually exclusive). INTERPRETATION: Many of the patients with cancer seen by surgeons affiliated with regional cancer centres in Ontario may be experiencing significant delays in the assessment and treatment of their cancer.

Aged↗
PubMed2000

Specifications for equipment used for infant pulmonary function testing. ERS/ATS Task Force on Standards for Infant Respiratory Function Testing. European Respiratory Society/ American Thoracic Society.

The aim of this position paper is to define minimal performance criteria for the separate items comprising equipment used to measure respiratory function in infants together with overall performance criteria for the assembled pieces of such equipment. These guidelines cover numerous aspects including: 1) safety, 2) documentation and maintenance of equipment, 3) physical characteristics of mechanical parts and signal transducers, and 4) data acquisition. Further, validation procedures for individual components as well as for the integrated equipment are recommended. Adherence to these guidelines should ensure that infant lung function measurements can be performed with an acceptable degree of safety, precision and reproducibility. They will also facilitate multicentre collection of data and performance of clinical investigations. Manufacturers of infant respiratory function equipment should make every effort to comply with these guidelines, which represent the current standards of paediatric health professionals in this field.

Data Collection↗
PubMed2000

Randomized phase III study of temozolomide versus dacarbazine in the treatment of patients with advanced metastatic malignant melanoma.

PURPOSE: To compare, in 305 patients with advanced metastatic melanoma, temozolomide and dacarbazine (DTIC) in terms of overall survival, progression-free survival (PFS), objective response, and safety, and to assess health-related quality of life (QOL) and pharmacokinetics of both drugs and their metabolite, 5-(3-methyltriazen-1-yl)imidazole-4-carboximide (MTIC). PATIENTS AND METHODS: Patients were randomized to receive either oral temozolomide at a starting dosage of 200 mg/m(2)/d for 5 days every 28 days or intravenous (IV) DTIC at a starting dosage of 250 mg/m(2)/d for 5 days every 21 days. RESULTS: In the intent-to-treat population, median survival time was 7.7 months for patients treated with temozolomide and 6.4 months for those treated with DTIC (hazards ratio, 1.18; 95% confidence interval [CI], 0.92 to 1.52). Median PFS time was significantly longer in the temozolomide-treated group (1.9 months) than in the DTIC-treated group (1.5 months) (P =.012; hazards ratio, 1.37; 95% CI, 1.07 to 1.75). No major difference in drug safety was observed. Temozolomide was well tolerated and produced a noncumulative, transient myelosuppression late in the 28-day cycle. The most common nonhematologic toxicities were mild to moderate nausea and vomiting, which were easily managed. Temozolomide therapy improved health-related QOL; more patients showed improvement or maintenance of physical functioning at week 12. Systemic exposure (area under the curve) to the parent drug and the active metabolite, MTIC, was higher after treatment with oral temozolomide than after IV administration of DTIC. CONCLUSION: Temozolomide demonstrates efficacy equal to that of DTIC and is an oral alternative for patients with advanced metastatic melanoma.

Adult↗
PubMed1999

Glucose-free medium in human in vitro fertilization and embryo transfer: a large-scale, prospective, randomized clinical trial.

OBJECTIVE: To determine whether excluding glucose from the culture medium used in a clinical IVF program improves human embryo quality and pregnancy rates. DESIGN: Randomized controlled trial. SETTING: Clinical assisted conception laboratory in a large teaching hospital. PATIENT(S): Seven hundred forty-one patients undergoing IVF-ET. INTERVENTION(S): Embryos were cultured from the pronucleate stage to ET in medium with glucose for patients in the control group and without glucose for patients in the trial group. MAIN OUTCOME MEASURE(S): Comparison of embryo quality and pregnancy rates between the two groups. RESULT(S): Embryo quality was enhanced with the use of glucose-free medium but pregnancy rates were similar. CONCLUSION(S): Although pregnancy rates remained similar in the two groups, a reduction in the glucose concentration of the medium used for embryo culture from the pronucleate stage to ET on day 2 or 3 is prudent.

Adult↗
PubMed1998

Quality of life assessment in the International Breast Cancer Study Group: past, present, and future.

UNLABELLED: The past: Since 1986, the IBCSG has been accruing a comprehensive longitudinal health-related quality of life (QL) database in addition to biomedical data of patients with early breast cancer who are receiving or have received adjuvant treatment. Our aim is to establish QL as a complementary outcome in randomized clinical trials and to gain new insight in biopsychosocial interactions. In regard to methodology, the IBCSG has made major contributions to the field through the development of global indicators, cross-cultural validation, impact of timing of assessments and working on practical and statistical issues relating to missing data. The present: In two large-scale clinical trials (IBCSG VI and VII) adjuvant chemotherapy (CMF) had a measurable effect on health-related QL, but contrary to expectations this effect was transient and minor compared with the effect of patients' adjustment and coping after diagnosis and surgery. THE FUTURE: In addition to the assessment of health-related QL, the IBCSG is currently developing and applying a global indicator for a patient-derived adapted utility concept in order to better assess the cost-benefit ratio of adjuvant treatment. However, the real challenge for the immediate future is the question how patients' adjustment can be fostered within primary care.

Breast Neoplasms↗
PubMed1998

International Breast Cancer Study Group trials.

The International Breast Cancer Study Group (IBCSG) was established in 1978 as the Ludwig Breast Cancer Study Group. It involved member institutions from Switzerland, Australia, New Zealand, Sweden, Italy, Slovenia, South Africa, Spain, Canada, Hong Kong and at various times from other countries. It has completed seven trials in three generations, and has a further eight trials currently open. Total accrual to December 1997 exceeds 12,000, and more than 9000 of these patients are in active follow-up. Early trials established the pattern of addressing important biological questions and adapting the randomisation to the risk group of the patient. The first two generations of trials demonstrated that combined modality chemoendocrine therapy was superior to endocrine therapy alone or no therapy in node-positive postmenopausal patients; that a single perioperative cycle improved disease-free survival (DFS) in node-negative patients, but was inferior to more prolonged therapy in node-positive patients; and that six conventionally timed cycles of CMF were as effective as seven cycles commenced in the perioperative period. Recently reported trials in node-positive patients showed that three early cycles of CMF chemotherapy added to tamoxifen in postmenopausal patients, while late reintroduction of chemotherapy appeared detrimental, particularly in patients with ER-negative tumors. In premenopausal patients six initial cycles were superior to three, especially in younger patients. Current studies in node-positive patients are addressing the role of a gap between courses of different chemotherapy, and the relative value of the anti-estrogens tamoxifen and toremifene. In node-negative premenopausal patients ovarian suppression with goserelin is being tested either instead of or added to CMF, while the value of initial CMF before tamoxifen is being tested in node-negative postmenopausal patients. For high-risk patients a triple-transplant regimen is being compared with conventional dose therapy. Planning for future trials recognises the need for rapid accrual of large numbers of similar patients, and therefore the need for inter-Group collaboration. The emergence of the Breast International Group as a consortium of European, Australasian and Canadian cooperative Groups is important to the rapid evaluation of new agents and strategies.

Antineoplastic Agents, Hormonal↗