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Biomedical subjects

P Cross

Publications and source records attributed to P Cross.

At least 19 recordsLinked to original sources
PubMed2006

Accelerated partial breast irradiation using interstitial high dose rate iridium brachytherapy: Early Australian experience and review of the literature.

Summary Accelerated partial breast irradiation (APBI) is an evolving new technique of adjuvant irradiation in selected women with early-stage breast cancer. We developed a pilot programme of APBI in 2000 and report end results in seven patients followed for a mean of 42.7 months (range 29-55 months). Good to excellent cosmesis and no loco-regional relapse or systemic metastases have occurred. The literature related to APBI is reviewed.

Aged↗
PubMed2005

Pro-poor strategies for urban water supply and sanitation services delivery in Africa.

Water utilities in Africa find it increasingly difficult to provide adequate services to the needy areas: their core business operations are often stagnant, compounded by a dramatic rise in peri-urban and poor settlements. To address these challenges, the Water and Sanitation Program Africa has designed a work program to disseminate the best practice in pro-poor service development and to help utilities and municipal authorities to develop roadmaps to the MDGs for their service areas. Activities will primarily be directed at: (i) helping utilities and municipal authorities to include pro-poor objectives in their reform; and, (ii) working jointly with local partners, CBOs and NGOs, and SSPs to develop strategies and actions specifically targeting informal settlements. WSP-AF will focus on utilities that are engaged in reform or planning to do so. This program builds on support developed for Water Utility Partnership (WUP#5). Key entry points for pro-poor strategies: (i) pro-poor tariffs and financing mechanisms for service improvement, (ii) institutional arrangements to improve services to the urban poor, (iii) pro-poor transaction design (including regulation and monitoring), (iv) advocacy and communications regarding the urban poor, and (v) consumer voice and civil society engagement.

Africa↗
PubMed2004

The role of human papillomavirus type 16 and the fragile histidine triad gene in the outcome of cervical neoplastic lesions.

The presence of high-risk human papillomavirus, loss of heterozygosity on chromosome 3p and fragile histidine triad gene expression were assessed as potential markers of cancer and CIN progression in 83 cervical cancers and 74 cervical intraepithelial neoplasia grade 1 lesions. Human papillomavirus type 16 was an indicator of vascular involvement in cancers. Loss of heterozygosity, especially in the fragile histidine triad gene intron 5, was an indicator of high-grade tumours, greater tumour depth and lymph node involvement. Abnormal fragile histidine triad gene expression was more frequent in cervical intraepithelial neoplasia grade 1 lesions with increased risk of disease progression.

Acid Anhydride Hydrolases↗
PubMed2003

A consensus development approach to define national research priorities in bone metastases: proceedings from NCIC CTG workshop.

AIMS: A 1-day workshop was conducted to gather interested Canadian radiation oncologists to identify priority research questions that could be answered through clinical trials under the auspices of the National Cancer Institute of Canada--Clinical Trials Group (NCIC-CTG) Symptom Control committee. MATERIALS AND METHODS: In preparation for the workshop, a survey of Canadian radiation oncologists resulted in four research areas in symptom control, including radiation-induced mucosal reactions, fatigue, radiotherapy for brain metastases and radiotherapy for bone metastases. The first half of the workshop consisted of plenary sessions where the research setting and perspective was defined for each area. This was followed by deliberations by a subgroup of researchers with special interest in the topic area. The bone-metastases subgroup deliberated the clinical context, the scientific merits and the required methodology of research questions related to the role of radiotherapy in early treatment of bone metastases, the role of re-irradiation, the role of systemic radiotherapy and patient selection for different fractionation schedules. A list of prioritised clinical studies was proposed. RESULTS: The question of single vs multi-fraction re-irradiation for symptomatic bone metastases was identified as most pertinent to the Canadian radiation oncologists present. A multi-centre, international intergroup study is undergoing protocol development. Other study concepts, such as an alternative dose-schedule of 17 Gy/2 fractions/1 week for intermediate-prognosis patients, and early referral for radiation oncologist assessment of early or mildly symptomatic bone metastases for good-prognosis patients, require further methodological development before a clinical trial can be proposed. CONCLUSION: An NCIC-CTG workshop provided an update on current evidence-based knowledge in palliative radiotherapy for bone metastases. New trial concepts were discussed among practitioners and clinical investigators to promote dialogue and collaboration. The proposal of an international intergroup randomised trial of single vs multiple fraction re-irradiation for painful bone metastases received the most support among participants.

Bone Neoplasms↗
PubMed2003

Treatment of localized prostate cancer using a combination of high dose rate Iridium-192 brachytherapy and external beam irradiation: initial Australian experience.

Combination high dose rate brachytherapy (HDRB) and external beam radiation therapy is technically and clinically feasible as definitive treatment for localized prostate cancer. We report the first large Australian experience using this technique of radiation dose escalation in 82 patients with intermediate- and high-risk disease. With a median follow up of 3 years (156 weeks), complications were low and overall prostate-specific antigen progression-free survival was 91% using the American Society for Therapeutic Radiology and Oncology consensus definition. The delivery of hypofractionated radiation through the HDRB component shortens overall treatment time and is both biologically and logistically advantageous. As a radiation boost strategy, HDRB is easy to learn and could be introduced into most facilities with brachytherapy capability.

Adenocarcinoma↗
PubMed2002

An investigation into the source of low energy scattered radiation of significance in film dosimetry.

The nature of the background optical density on films exposed to orthovoltage x-rays and electron beams has been studied for correction purposes. A higher than expected background value can be demonstrated by comparing the film scanned beam profile with water phantom ionisation scans of the same beam. A range of 3-5% increased background in the penumbral tail, with energy dependence, has been shown experimentally. Testing the assumption that this increased background is due to Cerenkov radiation produced in the film, Filmstrips were interleaved in a solid water equivalent phantom and exposed to 300kV orthovoltage x-ray beams and 5MeV to 12MeV electron beams. The film stacks were made up of single or multiple bare filmstrips, multiple filmstrips interleaved with black paper, and multiple filmstrips interleaved with overhead transparency sheet. The experimental result demonstrated that visible light was not significantly responsible for an enhanced film optical density, but rather that this was due to scattered radiation, with a complex low energy spectrum, arising from the film silver halide emulsion or base. An improved background correction technique is developed which incorporates this unexpected background value as an added component in the correction applied to the measured optical density. The resulting profiles exhibit improved agreement between film and ionization chamber measurements in the penumbra and tail regions.

Artifacts↗
PubMed2002

Measurement of the neutron and gamma doses accumulated during commercial jet flights from sydney to several major destinations in the northern and southern hemispheres.

As recommended by the ICRP, the European Union (EU) agreed to abide by mandatory monitoring of radiation doses to crew during civil aviation flights operated by the airlines of the EU member states. A large number of measured and theoretically predicted values for the in-flight radiation doses of northern hemisphere flight routes are available. On the other hand very few data have been published for the southern hemisphere. This paper will present the results of Australian domestic and intemational return flight routes originating from Sydney. The paper also presents results of trans-hemisphere air traffic routes. Neutron and gamma doses were measured using superheated bubble dosemeters and semiconductor detectors respectively. Based on our measurements a method is suggested whereby aircrew may share their personal radiation burden by flight crew hemisphere exchange.

Aerospace Medicine↗
PubMed2002

Relative thermoluminescence efficiency of TLD-600 and TLD-700 dosemeters irradiated with 59.8 MeV per nucleon krypton-86 ions.

A batch of LiF thermoluminescence dosemeters (TLDs), each containing five TLD-600 and TLD-700 thermoluminescence dosemeter chips, was irradiated with 59.85 MeV per nucleon 86Kr20+ ions from the K1200 superconducting cyclotron at the National Superconducting Cyclotron Laboratory (NSCL). Michigan State University, USA. The average linear energy transfer of the accelerated 86Kr ions and the resulting dose imparted to the TLD chips were calculated to be 3343 keV.microm(-1) per ion and 1.68 Gy respectively. A similar batch of TLD chips was irradiated with 1.3 MeV gamma rays from a 60Co source to 1.0 Gy. The TLD chips were evaluated at a ramp heating rate of 10 degrees C.s(-1) to 400 degrees C using a hot-finger type TLD reader. The thermoluminescence efficiency of the TLD-600 and TLD-700 dosemeters, relative to 60Co gamma rays was calculated to be 0.0025 and 0.0027 respectively

Fluorides↗
PubMed2001

Incidence of AD in African-Americans, Caribbean Hispanics, and Caucasians in northern Manhattan.

OBJECTIVE: To compare the incidence rates for AD among elderly African-American, Caribbean Hispanic, and white individuals and to determine whether coincident cerebrovascular disease contributes to the inconsistency in reported differences among ethnic groups. METHODS: This was a population-based, longitudinal study over a 7-year period in the Washington Heights and Inwood communities of New York City. Annual incidence rates for AD were calculated and compared by ethnic group, and cumulative incidence adjusted for differences in education, diabetes, cardiovascular risk factors, and stroke was calculated. RESULTS: The age-specific incidence rate for probable and possible AD was 1.3% (95% CI, 0.8 to 1.7) per person-year between the ages of 65 and 74 years, 4.0% (95% CI, 3.2 to 4.8) per person-year between ages 75 and 84 years, and 7.9% (95% CI, 5.5 to 10.5) per person-year for ages 85 and older. Compared to white individuals, the cumulative incidence of AD to age 90 years was increased twofold among African-American and Caribbean Hispanic individuals. Adjustment for differences in number of years of education, illiteracy, or a history of stroke, hypertension, heart disease, or diabetes did not change the disproportionate risks among the three ethnic groups. CONCLUSION: The incidence rate for AD was significantly higher among African-American and Caribbean Hispanic elderly individuals compared white individuals. The presence of clinically apparent cardiovascular or cerebrovascular disease did not contribute to the increased risk of disease. Because the proportion of African-American and Caribbean Hispanic individuals reaching ages 65 and older in the United States is increasing more rapidly than the proportion of white individuals, it is imperative that this disparity in health among the elderly be understood.

Aged↗
PubMed2001

Process of and problems in changing a birth defects registry reporting system.

BACKGROUND: The New York State (NYS) Department of Health (DOH) Congenital Malformations Registry (CMR), which began operations in 1982, was developed after the Love Canal crisis. New York hospitals are mandated to report children under age 2 years in whom a congenital anomaly is diagnosed. The CMR has tried to maintain a quality birth defects registry by using identifiers; narrative for defects; and completeness and accuracy, balanced with timeliness. In recent years, the existence of the registry has been questioned, and the NYS DOH evaluated the CMR to streamline it and to reduce the reporting burden on the hospitals. METHODS: Because NYS hospitals were already required to submit hospital discharge data through the Statewide Planning and Research Cooperative System (SPARCS), the CMR used this system as an alternative method for reporting. RESULTS: The evaluation indicated that the CMR, SPARCS, and hospital systems needed to be modified. Modifications needed to maintain registry quality were the most difficult. CMR staff worked closely with hospital personnel on all modifications so they would understand the reasons for the modifications. The changes were more global than originally anticipated, involving large national software vendors. CONCLUSIONS: The transition is ongoing. Additional work will be needed to verify data quality. Some of the modification will affect national software vendors and may be useful for other birth defects registries.

Congenital Abnormalities↗
PubMed2001

Cervical cytology EQA--the Northern experience.

The experience of the Northern region using the 1995 draft National Gynaecological Cervical Cytology External Quality Assurance (EQA) Scheme is given. Over three rounds, 390 staff reporting Cervical Cytology took part, and using a cumulative non-numeric marking scheme, five participants were deemed "unacceptable" at the end of three rounds. A total of 3450 responses were given to the 40 test slides used, with an overall false-positive rate of 5.9% and a false-negative rate of 1.4%. Grading was assessed for pathologists, and many appeared to perform badly by accumulating discrepancies for non-clinically-significant grading differences. The problems of slide selection/staining and grading consistency/accuracy are highlighted. This EQA scheme serves its dual function of education and identifying poor performance. It must be seen as a viable EQA scheme, although other options must be considered, given advances in technology.

False Negative Reactions↗
PubMed2001

A framework for improving the quality of health information on the world-wide-web and bettering public (e-)health: the MedCERTAIN approach.

There has been considerable debate about the variable quality of health information on the world-wide-web and its impact on public health. While central authorities to regulate, control, censor, or centrally approve information, in-formation providers or websites are neither realistic nor desirable, public health professionals are interested in making systems available that direct patient streams to the best available information sources. National governments and medical societies have also recognized their responsibility to help users to identify "good quality" information sources. But what constitutes good quality, and how can such a system be implemented in a decentralized and democratic manner? This paper presents a model which combines aspects of consumer education, encouragement of best practices among information providers, self-labeling and external evaluations. The model is currently being implemented and evaluated in the MedCERTAIN project, funded by the European Union under the Action Plan for Safer Use of the Internet. The aim is to develop a technical and organisational infrastructure for a pilot system that allows consumers to access metainformation about web-sites and health information providers, including disclosure information from health providers and opinions of external evaluators. The paper explains the general conceptual framework of the model and presents preliminary experiences including results from an expert consensus meeting, where the framework was discussed.

Databases as Topic↗
PubMed2001

A metadata vocabulary for self- and third-party labeling of health web-sites: Health Information Disclosure, Description and Evaluation Language (HIDDEL).

We describe HIDDEL (Health Information Disclosure, Description and Evaluation Language), formerly known as medPICS (platform for Internet content selection in medicine), a metadata vocabulary designed to enhance transparency, trust and quality of health information on the web. The vocabulary may be used (1) by webmasters to self-describe their contents and policies; (2) by infomediaries (e.g. Healthfinder, NHS Direct/NeLH), e.g. third party evaluators, rating or portal services, to annotate other websites; (3) and by users, to describe their preferences. As an XML application it conforms to the W3C's RDF Specification. The metadata vocabulary is primarily intended to enable descriptions of whole health websites or health information providers. The vocabulary is designed to provide a computer-readable electronic "label" of a health website, telling users who is behind the website, how the website is sponsored, what the con-tent, aim and target audience is, how the information was compiled, what risks the service bears, or what people say about the resource. Client-software can "read" this label automatically, compare it to the user s own set of preferences and needs, and alert and advise users.

Information Services↗
PubMed2000

A clinical review of borderline glandular cells on cervical cytology.

OBJECTIVE: To review the diagnoses and diagnostic pathway of women presenting with borderline glandular cells on cervical cytology. To outline the basis of clinical approach of these women. DESIGN: Retrospective review. POPULATION: Forty-three women referred to the hospital department over a 32-month period. METHODS: Review of the casenotes for the demographic data, previous cervical cytology and/or histology report, indication for the smear resulting in borderline glandular cells, colposcopic findings, diagnostic and/or treatment procedures, final diagnosis and current status. RESULTS: The average age was 36.7 years. Twenty-four women (56%) had clinically significant lesions: seven women (16%) presented with cancers, of which one was endometrial in origin, and 17 (40%) with intraepithelial neoplasia (CIN and cervical glandular intraepithelial neoplasia (CGIN)). Sixty-seven percent of all clinically significant lesions were of squamous origin. Thirty-seven had histological diagnosis, while six went on to cytological surveillance. Colposcopy was the most significant predictor for clinically significant lesions (P < 0.05). Punch biopsies and loop excisions were diagnostic when based on abnormal colposcopic findings. Brush cytology was appropriate follow up for asymptomatic, premenopausal women with no colposcopic abnormality. In addition, endometrial sampling was recommended in the peri- and postmenopausal women. CONCLUSION: Borderline glandular cells have a high incidence of clinically significant lesions. Immediate referral for colposcopy and assessment is strongly recommended in women with two borderline glandular smears to avoid delays in potential cancer diagnosis.

Adult↗
PubMed2000

Dexamethasone for the prophylaxis of radiation-induced emesis: a National Cancer Institute of Canada Clinical Trials Group phase III study.

PURPOSE: To investigate the efficacy of dexamethasone as a prophylactic antiemetic for patients receiving fractionated radiotherapy to the upper abdomen in a randomized controlled trial. PATIENTS AND METHODS: One hundred fifty-four patients planned to receive fractionated radiotherapy to fields involving the upper abdomen (minimum total dose, 20 Gy; minimum number of fractions, five) were randomized to receive prophylactic dexamethasone (2 mg orally three times a day [tid], starting in the morning of first treatment and continuing until after their fifth treatment) or placebo. The primary end point of the study was the proportion of patients free from emesis during the study period. Secondary end points included a quality-of-life assessment using the core questionnaire of the European Organization for Research and Treatment of Cancer and side effects of dexamethasone therapy in this population of patients. RESULTS: Fifty-four (70%) out of 75 patients receiving dexamethasone had complete protection versus 37 (49%) out of 75 patients on placebo (P = .025). Most emetic episodes occurred during the initial phase of treatment. Although there was no difference in global quality of life between the two sets of patients, patients receiving dexamethasone had less nausea and vomiting and less loss of appetite but more insomnia. CONCLUSION: Dexamethasone 2 mg tid seems to be an effective prophylactic antiemetic in this situation. Side effects were acceptable, but there seemed to be no overall effect on global quality of life.

Abdomen↗