PubMed Health⌕ Search

Biomedical subjects

Richard Stephens

Publications and source records attributed to Richard Stephens.

At least 19 recordsLinked to original sources
PubMed2006

Seroprevalence of Toxoplasma gondii in pregnant women and cats in Grenada, West Indies.

Prevalence of antibodies against Toxoplasma gondii was studied in 534 pregnant women and 40 domestic cats in Grenada, West Indies. Antibodies (IgG) for T. gondii were sought in human sera by an enzyme-linked immunosorbent assay and in cat sera by using the modified agglutination test (MAT). Antibodies were found in 57 % of pregnant women. Seroprevalence increased with age; 51% of 15- to 19-yr-old women (100 total) had antibodies versus 60% of 20- to 24-yr-old women (127 total). Antibodies to T. gondii (MAT, 1:25 serum dilution) were found in 35% of cats; titers were 1:25 in 7 cats, 1:50 in 4 cats, and 1:500 in 3 cats. Epidemiological data suggested that the ingestion of food or water contaminated with oocysts was an important mode of transmission of T. gondii to women.

Adolescent↗
PubMed2006

Cost effectiveness of increasing the dose intensity of chemotherapy with granulocyte colony-stimulating factor in small-cell lung cancer: based on data from the Medical Research Council LU19 trial.

BACKGROUND: The use of granulocyte colony-stimulating factor (G-CSF) can enable dose intensification of chemotherapy in small-cell lung cancer (SCLC). However, given its acquisition cost, it is important to assess its cost effectiveness within a resource-constrained health service. OBJECTIVE: To assess the cost effectiveness, from the UK NHS perspective, of G-CSF given in addition to doxorubicin, cyclophosphamide and etoposide (ACE) versus ACE alone in the management of SCLC. METHODS: Using data from a UK Medical Research Council trial (LU19) to assess chemotherapy dose intensification in patients with previously untreated SCLC of any disease extent, a retrospective cost-effectiveness analysis was undertaken. Resource use data, including hospitalisations and non-protocol cancer treatments, were collected during the first 6-month treatment phase of the trial. Mean costs ( pound, 2003 values) of managing patients in the two arms of the trial were calculated. Mean survival duration was calculated for the two groups using patient-specific follow-up data collected in the trial. Incremental cost-effectiveness analysis was undertaken, and uncertainty in cost effectiveness was expressed using cost-effectiveness acceptability curves. RESULTS: The use of G-CSF in addition to ACE chemotherapy is more costly ( 4647 pounds) but results in longer mean survival duration (0.20 years; 0.18 years when discounted). This generates an incremental cost per additional life-year of 25,816 pounds for ACE + G-CSF therapy. The probability of the addition of G-CSF being cost effective, if decision makers are willing to pay 30,000 pounds for an additional life-year, is 0.57. Secondary analysis suggests that cost effectiveness is likely to be sensitive to assumptions about the health-related quality of life (HR-QOL) experienced by patients. CONCLUSION: Based on data collected in the LU19 trial, chemotherapy dose intensification using G-CSF in SCLC adds to health service costs but increases survival duration. Its overall cost effectiveness is likely to be finely balanced.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Sentinel nodes are identifiable in formalin-fixed specimens after surgeon-performed ex vivo sentinel lymph node mapping in colorectal cancer.

BACKGROUND: In recent years, the technique of sentinel lymph node (SLN) mapping has been applied to colorectal cancer. One aim was to ultrastage patients who were deemed node negative by routine pathologic processing but who went on to develop systemic disease. Such a group may benefit from adjuvant chemotherapy. METHODS: With fully informed consent and ethical approval, 37 patients with primary colorectal cancer and 3 patients with large adenomas were prospectively mapped. Isosulfan blue dye (1 to 2 mL) was injected around tumors within 5 to 10 minutes of resection. After gentle massage to recreate in vivo lymph flow, specimens were placed directly into formalin. During routine pathologic analysis, all nodes were bivalved, and blue-staining nodes were noted. These later underwent multilevel step sectioning with hematoxylin and eosin and cytokeratin staining. RESULTS: SLNs were found in 39 of 40 patients (98% sensitivity), with an average of 4.1 SLNs per patient (range, 1-8). In 14 of 16 (88% specificity) patients with nodal metastases on routine reporting, SLN status was in accordance. Focused examination of SLNs identified occult tumor deposits in 6 (29%) of 21 node-negative patients. No metastatic cells were found in SLNs draining the three adenomas. CONCLUSIONS: The ability to identify SLNs after formalin fixation increases the ease and applicability of SLN mapping in colorectal cancer. Furthermore, the sensitivity and specificity of this simple ex vivo method for establishing regional lymph node status were directly comparable to those in previously published reports.

Adenoma↗
PubMed2005

Economic benefits of substance abuse treatment: findings from Cuyahoga County, Ohio.

We estimated long-term economic benefits and treatment costs for a sample of substance abuse clients who received treatment in Cuyahoga County, Ohio, using health, criminal activity, and earnings data from the Persistent Effects of Treatment Studies. Clients were interviewed at baseline and 6, 12, 24, and 30 months following baseline. We find positive benefits from substance abuse treatment, almost of all of which were derived from reduced criminal activity and increased real earnings, with overall benefit-to-cost ratios ranging from 2.8 to 4.1. The reductions in costs to society were found to be persistent over the long-term, 30-month follow-up period. On average, treatment was found to be cost beneficial regardless of the number of times a client entered treatment in the baseline or follow-up periods. Clients who entered residential treatment and then step down to less intensive care showed greater treatment benefits than clients who only received residential treatment.

Adolescent↗
PubMed2005

It's good to talk: comparison of a telephone helpline and website for cancer information.

The Internet plays an important role in the information gathering process for people affected by cancer. This paper presents the results of a study comparing two sources of cancer information; a website and a telephone helpline. Data were captured on the use of one section of the UK charity CancerBACUP's website, and systematically compared to data collected from every fifth user of the charity's helpline. Subjects of enquiry for 994 telephone enquiries and 3096 web enquiries were comparable. The majority of enquiries to both services were about women and/or patients aged 50 or older. Website users were more likely than helpline users to request factual information and less likely to request information on sensitive topics. This study provides valuable information about the types of health information people seek from different sources and how the sources may complement each other.

Adult↗
PubMed2005

A randomised comparison of radical radiotherapy with or without chemotherapy for patients with non-small lung cancer: results from the Big Lung Trial.

BACKGROUND: A meta-analysis of trials comparing primary treatment with or without chemotherapy for patients with non-small cell lung cancer published in 1995 suggested a survival benefit for cisplatin-based chemotherapy in each of the primary treatment settings studied, but it included many small trials, and trials with differing eligibility criteria and chemotherapy regimens. METHODS: The Big Lung Trial was a large pragmatic trial designed to confirm the survival benefits seen in the meta-analysis, and this paper reports the findings in the radical radiotherapy setting. The trial closed before the required sample size was achieved due to slow accrual, with a total of 288 patients randomised to receive radical radiotherapy alone (146 patients) or sequential radical radiotherapy and cisplatin-based chemotherapy (142 patients). RESULTS: There was no evidence that patients allocated sequential chemotherapy and radical radiotherapy had a better survival than those allocated radical radiotherapy alone, HR 1.07 (95% CI 0.84-1.38, P=0.57), median survival 13.0 months for the sequential group and 13.2 for the radical radiotherapy alone group. In addition, exploratory analyses could not identify any subgroup that might benefit more or less from chemotherapy. CONCLUSIONS: Despite not suggesting a survival benefit for the sequential addition of chemotherapy to radical radiotherapy, possibly because of the relatively small sample size and consequently wide confidence intervals, the results can still be regarded as consistent with the meta-analysis, and other similarly designed recently published large trials. Combining all these results suggests there may be a small median survival benefit with chemotherapy of between 2 and 8 weeks.

Aged↗
PubMed2005

Neuropsychological impairment as a consequence of football (soccer) play and football heading: a preliminary analysis and report on school students (13-16 years).

Footballers run the risk of incurring mild head injury from a variety of sources, including the intentional use of the head to play the ball, known as heading. This paper presents a preliminary exploratory analysis of data collected to examine whether cumulative incidence of mild head injury, or cumulative heading frequency, are related to neuropsychological functioning in male adolescent footballers. In a quasi-experimental cross-sectional design, neuropsychological test scores of school team footballers were compared with those of similarly aged rugby players and noncontact sport players. Cumulative mild head injury incidence was estimated using self-reports, and cumulative heading was estimated using a combination of observation and self-reports. No participants had sustained a head injury within 3 months of testing. There was no relationship between head injury and neuropsychological performance, and there were no decrements in either the footballers or the rugby players in comparison with the noncontact sport players. Within the footballers, cumulative heading did not predict any of the neuropsychological test scores. These findings indicate the absence of neuropsychological impairment arising due to cumulative mild head injury incidence, or cumulative heading. Although these null findings may be reassuring to players, parents, and football organizers, we stress that they are preliminary. Further data is being collected from the same populations to provide more reliable effect estimates.

Adolescent↗
PubMed2004

Bioinformatic analysis of primary endothelial cell gene array data illustrated by the analysis of transcriptome changes in endothelial cells exposed to VEGF-A and PlGF.

We recently published a review in this journal describing the design, hybridisation and basic data processing required to use gene arrays to investigate vascular biology (Evans et al. Angiogenesis 2003; 6: 93-104). Here, we build on this review by describing a set of powerful and robust methods for the analysis and interpretation of gene array data derived from primary vascular cell cultures. First, we describe the evaluation of transcriptome heterogeneity between primary cultures derived from different individuals, and estimation of the false discovery rate introduced by this heterogeneity and by experimental noise. Then, we discuss the appropriate use of Bayesian t-tests, clustering and independent component analysis to mine the data. We illustrate these principles by analysis of a previously unpublished set of gene array data in which human umbilical vein endothelial cells (HUVEC) cultured in either rich or low-serum media were exposed to vascular endothelial growth factor (VEGF)-A165 or placental growth factor (PlGF)-1(131). We have used Affymetrix U95A gene arrays to map the effects of these factors on the HUVEC transcriptome. These experiments followed a paired design and were biologically replicated three times. In addition, one experiment was repeated using serial analysis of gene expression (SAGE). In contrast to some previous studies, we found that VEGF-A and PlGF consistently regulated only small, non-overlapping and culture media-dependant sets of HUVEC transcripts, despite causing significant cell biological changes.

Cells, Cultured↗
PubMed2004

Role of glucose in chewing gum-related facilitation of cognitive function.

This study tests the hypothesis that chewing gum leads to cognitive benefits through improved delivery of glucose to the brain, by comparing the cognitive performance effects of gum and glucose administered separately and together. Participants completed a battery of cognitive tests in a fully related 2 x 2 design, where one factor was Chewing Gum (gum vs. mint sweet) and the other factor was Glucose Co-administration (consuming a 25 g glucose drink vs. consuming water). For four tests (AVLT Immediate Recall, Digit Span, Spatial Span and Grammatical Transformation), beneficial effects of chewing and glucose were found, supporting the study hypothesis. However, on AVLT Delayed Recall, enhancement due to chewing gum was not paralleled by glucose enhancement, suggesting an alternative mechanism. The glucose delivery model is supported with respect to the cognitive domains: working memory, immediate episodic long-term memory and language-based attention and processing speed. However, some other mechanism is more likely to underlie the facilitatory effect of chewing gum on delayed episodic long-term memory.

Adolescent↗
PubMed2004

Quality of life.

Explore the source record for details and available documents.

Antineoplastic Agents↗
PubMed2004

Palliative treatment for advanced non-small cell lung cancer.

It should go without saying that all patients with advanced NSCLC are entitled to the treatment and care described in this article. It is probably also true that in many countries where these patients are often elderly and socially disadvantaged, they may have very variable access to this treatment and care. There is reasonable research evidence that both chemotherapy and palliative radiotherapy are modestly effective in controlling symptoms and prolonging life for some patients, but with significant risks of unpleasant and sometimes life-threatening toxicity. For this large and important group of patients, however, there are a large number of unanswered questions about the best regimens to use, how best to select patients so that they get the greatest benefit, how to mitigate side effects, and how best to integrate all the available treatment options. There have been significantly more trials in chemotherapy, but we must not overlook the need for research into palliative radiotherapy and other supportive care measures. There is still plenty of scope for intelligent and coordinated research.

Carcinoma, Non-Small-Cell Lung↗
PubMed2004

Neuropsychological effects of long-term low-level organophosphate exposure in orchard sprayers in England.

The health effects from prolonged low-level organophosphate exposure are unknown. We hypothesized that exposed individuals would show neuropsychological decrements when compared with unexposed individuals, and that cumulative organophosphate exposure would be correlated with neuropsychological performance. We used a quasiexperimental cross-sectional design to compare neuropsychological test scores among three groups: orchard sprayers exposed to organophosphates, and construction worker and pig farm workers who were not exposed. Relative to construction workers, orchard sprayers were significantly slower on negative statements of the syntactic reasoning test. However, we found no relationship between cumulative exposure and test response. The slower response of the orchard sprayers was apparently exposure-related, but we could not identify an underlying neurotoxic mechanism. Therefore, we are unable to conclude whether this is a specific cognitive effect, or a decrement arising on the most sensitive test employed.

Adult↗