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Biomedical subjects

J Bryant

Publications and source records attributed to J Bryant.

At least 37 records · Page 2Linked to original sources
PubMed2001

Modifications of microvascular filtration capacity in human limbs by training and electrical stimulation.

This study investigated whether an increase in microvascular surface area as a result of endurance training, which increases human skeletal muscle capillarity, would translate to greater capacity for fluid filtration compared with strength training, which does not affect capillary supply. Values for filtration capacity, Kf, derived from the slope of calf volume change, Jv, measured by venous occlusion plethysmography, against cuff pressure during a protocol of small cumulative pressure steps, were significantly higher in endurance athletes (5.78 +/- 0.88 mL min(-1) 100 mL(-1) mmHg(-1) x 10(-3), P < 0.05) than controls (3.38 +/- 0.32 mL min(-1) 100 mL(-1) mmHg(-1) x 10(-3) whereas strength-trained athletes had values similar to control (4.08 +/- 0.56 mL min(-1) 100 mL(-1) mmHg(-1) x 10(-3), ns), suggesting that surface area is important. However, when sedentary subjects underwent either a 4-week unilateral dynamic plantarflexion training programme (70% peak power, 20 min day(-1), 5 days week(-1) or a calf muscle electrical stimulation programme (8 Hz, 3 x 20 min day(-1), 5 days week(-1), neither of which caused limb blood flow to alter after training nor would be expected to increase capillarity, only the stimulation group showed a significant increase in Kf (6.68 +/- 0.62 mL min(-1) 100 mL(-1) mmHg(-1) x 10(-3) post-training vs. 3.38 +/- 0.38 pre-training, P < 0.05). This may be because stimulation enhances perfusion preferentially to glycolytic fibres, or maintains high levels of vascular endothelial growth factor (VEGF) or changes lymph clearance.

Adaptation, Physiological↗
PubMed2001

Studies of the microstructure of polymer-modified bitumen emulsions using confocal laser scanning microscopy.

Polymer-modified bitumen emulsions present a safer and more environmentally friendly binder for enhancing the properties of roads. Cationic bitumen emulsion binders containing polymer latex were investigated using confocal laser scanning microscopy. The latex was incorporated into the bitumen emulsion by using four different addition methods and all emulsions were processed with a conventional colloid mill. The emulsion binder films were studied after evaporation of the emulsion aqueous phase. We show how the microstructure and distribution of the polymer varies within the bitumen binder depending on latex addition method, and that the microstructure of the binder remains intact when exposed to elevated temperature. It was found that a distinctly fine dispersion of polymer results when the polymer is blended into the bitumen before the emulsifying process (a monophase emulsion). In contrast, bi-phase emulsion binders produced by either post-adding the latex to the bitumen emulsion, or by adding the latex into the emulsifier solution phase before processing, or by comilling the latex with the bitumen, water and emulsifier all resulted in a network formation of bitumen particles surrounded by a continuous polymer film. The use of emulsified binders appears to result in a more evenly distributed polymer network compared to the use of hot polymer-modified binders, and they therefore have greater potential for consistent binder cohesion strength, stone retention and therefore improved pavement performance.

Journal Article↗
PubMed2001

Adjuvant therapy for very young women with breast cancer: need for tailored treatments.

Breast cancer rarely occurs in women below the age of 35 years. Data from various sources indicate that diagnosis at such an age is associated with a dire prognosis mainly because of a more aggressive presentation. Although the effect of chemotherapy for premenopausal patients is substantial, recent evidence on 2233 patients suggested that very young women with endocrine-responsive tumors had a statistically significantly higher risk of relapse than older premenopausal patients with such tumors. In contrast, results for younger and older premenopausal patients were similar if their tumors were classified as endocrine nonresponsive. Information from studies on 7631 patients who were treated with chemotherapy alone in trials of three major U.S. cooperative groups showed a similar interaction between the effect of age and steroid hormone receptor status of the primary tumor. Better treatments for very young patients are required and may involve ovarian function suppression in addition to other endocrine agents in patients with endocrine responsive tumors and a more precise investigation of chemotherapy and its timing, duration, and intensity in those with endocrine nonresponsive tumors. Very young women with this disease are faced with personal, family, professional, and quality-of-life issues, which further complicate the phase of treatment decision making. The development of more effective therapies for younger patients requires tailored treatment investigations and cannot rely on information predominantly contributed from older premenopausal women.

Adult↗
PubMed2001

Duration of adjuvant tamoxifen therapy.

The benefit of using adjuvant tamoxifen to treat breast cancer has been firmly established for patients with estrogen receptor (ER)-positive tumors, regardless of age, lymph node status, or menopausal status. Uncertainty remains, however, regarding the optimal duration of tamoxifen therapy. We reviewed the findings of randomized clinical trials that directly compared alternative treatment durations. Trials comparing short-term adjuvant treatment with tamoxifen (i.e., 1-3 years) with treatments having durations of about 5 years consistently have demonstrated additional benefits stemming from the longer therapy. Trials testing 5 years of treatment with longer durations have, in the aggregate, suggested no additional benefit for the patient. Nevertheless, the number of recurrences reported to date in these trials is not large, and the results of the individual trials are heterogeneous. Furthermore, as a result of tamoxifen's "carryover" effect, duration trials require considerable follow-up before definitive results can be established. Until more definitive data become available, adjuvant treatment with tamoxifen should be limited to 5 years outside the clinical trials setting. Continued accrual of ER-positive patients to ongoing tamoxifen duration trials, including the Adjuvant Tamoxifen Treatment Offer More (aTTom) and Adjuvant Tamoxifen Longer Against Shorter (ATLAS) trials, is appropriate. Alternatively, patients who remain disease free after 5 years of tamoxifen therapy should be encouraged to participate in trials testing crossover to other hormonal interventions, including selective ER modulators or aromatase inhibitors.

Antineoplastic Agents, Hormonal↗
PubMed2001

Preoperative chemotherapy in patients with operable breast cancer: nine-year results from National Surgical Adjuvant Breast and Bowel Project B-18.

National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-18 was initiated in 1988 to determine whether four cycles of doxorubicin/cyclophosphamide given preoperatively improve survival and disease-free survival (DFS) when compared with the same chemotherapy given postoperatively. Secondary aims included the evaluation of preoperative chemotherapy in downstaging the primary breast tumor and involved axillary lymph nodes, the comparison of lumpectomy rates and rates of ipsilateral breast tumor recurrence (IBTR) in the two treatment groups, and the assessment of the correlation between primary tumor response and outcome. Initially published findings were based on a follow-up of 5 years; this report updates results through 9 years of follow-up. There continue to be no statistically significant overall differences in survival or DFS between the two treatment groups. Survival at 9 years is 70% in the postoperative group and 69% in the preoperative group (P =.80). DFS is 53% in postoperative patients and 55% in preoperative patients (P =.50). A statistically significant correlation persists between primary tumor response and outcome, and this correlation has become statistically stronger with longer follow-up. Patients assigned to preoperative chemotherapy received notably more lumpectomies than postoperative patients, especially among patients with tumors greater than 5 cm at study entry. Although the rate of IBTR was slightly higher in the preoperative group (10.7% versus 7.6%), this difference was not statistically significant. Marginally statistically significant treatment-by-age interactions appear to be emerging for survival and DFS, suggesting that younger patients may benefit from preoperative therapy, whereas the reverse may be true for older patients.

Aged↗
PubMed2001

Systematic review of immunomodulatory drugs for the treatment of people with multiple sclerosis: Is there good quality evidence on effectiveness and cost?

OBJECTIVE: To review the clinical effectiveness and costs of a range of disease modifying drugs in multiple sclerosis. Drugs included are azathioprine, cladribine, cyclophosphamide, intravenous immunoglobulin, methotrexate, and mitoxantrone. METHODS: Electronic databases and bibliographies of related papers were searched for randomised controlled trials (RCTs) and systematic reviews, and experts and pharmaceutical companies were contacted for further information. Inclusion and quality criteria were assessed, data extraction undertaken by one reviewer and checked by a second reviewer, with discrepancies being resolved through discussion. Costs were obtained and cost-effectiveness papers sought. RESULTS: Seventeen studies met the inclusion criteria for the review. Evidence for the clinical effectiveness of the drugs showed some reductions in relapse rates and/or progression to disability for people with MS, although benefits may be lessened by wide ranging side effects. Annual drug costs/patient are estimated to range from 60 pounds to 10200 pounds. No cost effectiveness studies were found. CONCLUSION: Evidence for the effectiveness of these drugs in multiple sclerosis is problematic because there are few good quality trials for each drug. Trials often have methodological limitations and use different treatment regimes, patient groups, and outcome measures. Well conducted trials using outcome measures with clinical significance for groups of patients with different types of multiple sclerosis and long term follow up are needed if the evidence base of treatment for the disease is to be improved.

Adjuvants, Immunologic↗
PubMed2001

Use of drug sellers by old people in northeast Thailand.

The paper describes an exploratory study of the use of private drug sellers by people age 60 and over in three districts in northeast Thailand. The survey paid special attention to problems of under-reporting, and found that respondents visited drug sellers two or three times a month--a much higher frequency than usually reported. The typical reason for visiting a drug seller was to obtain one or two days' worth of modern medicines to treat the symptoms of non-acute conditions. The paper discusses ways to improve on current survey methods for studying private drug sellers.

Aged↗
PubMed2001

Immunomodulatory drugs for multiple sclerosis: a systematic review of clinical and cost effectiveness.

Uncertainties about the clinical and cost effectiveness of immunomodulatory drugs for multiple sclerosis (MS), as well as concerns about funding treatment, continue to influence their use. The National Institute for Clinical Excellence (NICE) in England and Wales has been appraising the evidence on the clinical and cost effectiveness of IFN-beta and glatiramer to provide guidance to the NHS. It has proved a difficult task. This paper is an update of our systematic review which assesses the evidence on the clinical and cost effectiveness of a range of immunomodulatory drugs for MS, including azathioprine, IFN-beta, cladribine, cyclophosphamide, glatiramer, intravenous immunoglobulin (IVIg), methotrexate and mitoxantrone. Searches of electronic databases (such as Medline, Embase and the Cochrane Library) and bibliographies of related papers, as well as consultation with experts, for systematic reviews of randomised controlled trials (RCTs) and direct reports of RCTs revealed 26 studies of clinical effectiveness and eight economic evaluations that met the criteria for inclusion. The quality of the evidence was often poor, affected by methodological limitations. Evidence on the clinical effectiveness of immunomodulatory drugs showed some clinical effect, with reductions in relapse rates and/or progression to disability for people with MS. However, benefits from these drugs may be lessened by side effects. Assessment of cost effectiveness was limited to IFN-beta and glatiramer, showing that any benefit from these drugs was achieved at very high cost. The inadequacies in the evidence of clinical and cost effectiveness on some immunomodulatory drugs for the treatment of people with MS necessitate further rigorous RCTs and comparative economic evaluations of different alternatives.

Azathioprine↗
PubMed2001

Clinical and cost-effectiveness of donepezil, rivastigmine and galantamine for Alzheimer's disease: a rapid and systematic review.

BACKGROUND: Alzheimer's disease is the most common cause of dementia and is characterised by an insidious onset and slow deterioration. The estimated prevalence of Alzheimer's disease for a standard health authority (500,000 people) is about 3330. Current service involves a wide range of agencies, and drug therapy for some patients. OBJECTIVES: To provide a rapid and systematic review of the clinical effectiveness and cost-effectiveness of donepezil, rivastigmine and galantamine in the symptomatic treatment of people suffering from Alzheimer's disease. METHODS: A systematic review of the literature was undertaken. METHODS - DATA SOURCES: Searches were made of electronic databases, including MEDLINE, EMBASE, The Cochrane Library, Database of Abstracts of Reviews of Effectiveness, NHS Economic Evaluation Database, National Research Register, Science Citation Index, BIOSIS, EconLit, MRC Trials database, Early Warning System, Current Controlled Trials, TOXLINE, Index of Scientific and Technical Proceedings, and Getting Easier Access to Reviews. All sources were searched over the period covered by the databases up to March/July 2000. Bibliographies of related papers were assessed for relevant studies and experts were contacted for advice and peer review, and to identify additional published and unpublished references. Manufacturer submissions to the National Institute for Clinical Excellence (NICE) were reviewed. METHODS - STUDY SELECTION: Studies were included if they fulfilled the following criteria: (1) INTERVENTION: donepezil, rivastigmine or galantamine used to treat Alzheimer's disease. (2) PARTICIPANTS: people diagnosed with Alzheimer's disease who meet the criteria for treatment with donepezil, rivastigmine and galantamine. (3) OUTCOMES: measures assessing changes in cognition, function, behaviour and mood, quality of life (including studies assessing carer well-being and carer-input), and time to institutionalisation. (4) DESIGN: systematic reviews of randomised controlled trials (RCTs) and RCTs comparing donepezil, rivastigmine or galantamine with placebo or each other or non-drug comparators were included in the review of effectiveness. Economic studies of donepezil, rivastigmine or galantamine used to treat Alzheimer's disease that included a comparator (or placebo) and both the costs and consequence (outcomes) of treatment were included in the review of cost-effectiveness. Studies in non-English language, and abstracts and conference poster presentations of systematic reviews, RCTs and economic evaluations were excluded. Two reviewers identified studies by independently screening study titles and abstracts, and then by examining the full text of selected studies to decide inclusion. METHODS - DATA EXTRACTION AND QUALITY ASSESSMENT: Data extraction and quality assessment were undertaken by one reviewer and checked by a second reviewer, with any disagreements resolved through discussion. The quality of RCTs was assessed using the Jadad scale and the quality of systematic reviews was assessed using criteria developed by the NHS Centre for Reviews and Dissemination. The quality of economic evaluation studies was assessed by their internal validity (i.e. the methods used) using a standard checklist, and external validity (i.e. the generalisability of the economic study to the population of interest) using a series of relevant questions. METHODS - DATA SYNTHESIS: The clinical effectiveness and cost-effectiveness of donepezil, rivastigmine and galantamine were synthesised through a narrative review with full tabulation of results of all included studies. In the economic evaluation, the reviewers assessed whether adjustments could be made to existing models to reflect the current situation in England and Wales. RESULTS - CLINICAL EFFECTIVENESS: (1) Donepezil--three systematic reviews and five RCTs (plus four studies from industry (unpublished data, submitted as commercial in confidence)) were found. Results suggest that donepezil is beneficial when assessed using global and cognitive outcome measures. (2) Rivastigmine--three systematic reviews and five RCTs (plus two studies from industry (unpublished data, submitted as commercial in confidence)) were found. Results suggest that rivastigmine is beneficial in terms of global outcome measures. (3) Galantamine--one systematic review and three RCTs (plus three studies from industry (unpublished data, submitted as commercial in confidence)) were found. Results suggest that galantamine is beneficial in terms of global, cognitive and functional scales. RESULTS - SUMMARY OF BENEFITS: It is difficult to quantify benefits from the evidence available in the literature. Statistically significant improvements in tests such as ADAS-cog (Alzheimer's Disease Assessment Scale cognitive subscale) may not be reflected in changes in daily life. (ABSTRACT TRUNCATED)

Alzheimer Disease↗
PubMed2001

Contamination of beef chucks with Escherichia coli during carcass breaking.

Samples were obtained by swabbing the whole of the chuck portion on each of the first 500 sides that entered a beef carcass breaking process and the whole of the outer surface of each of the chuck primal cuts that were prepared from those portions. Swabs obtained from groups of 10 sides or cuts that entered or emerged from the process consecutively were combined, and the coliforms and Escherichia coli recovered from each group were enumerated. Coliforms and E. coli were recovered only sporadically from groups of sides at log total numbers of 4.0 and 3.5 log CFU/500 sides, respectively. Coliforms were recovered from three and E. coli from none of the first six groups of cuts. Coliforms and E. coli were recovered from all subsequent groups of cuts, initially at log numbers mostly <3 log CFU/10 cuts, but ultimately at log numbers mostly >3 log CFU/10 cuts. The log total numbers of coliforms and E. coli recovered from cuts were >6.0 and 5.5 log CFU/500 cuts, respectively. After the breaking of about 600 sides, samples were obtained by swabbing a table onto which the part of the side that included the chuck portion was deposited after it was cut from the hanging side, and the belt that was used for conveying chucks. The numbers of coliforms and E. coli recovered from the table and conveyor belt were comparable with the numbers recovered from sides and cuts, respectively. Those findings show that most of the coliforms and E. coli recovered from the cuts were not present on carcass sides but that they originated largely from the cut conveying equipment.

Abattoirs↗
PubMed2001

A survey to identify the clinical coding and classification systems currently in use across Europe.

INTRODUCTION: This is a survey to identify what clinical coding systems are currently in use across the European Union, and the states seeking membership to it. We sought to identify what systems are currently used and to what extent they were subject to local adaptation. BACKGROUND: Clinical coding should facilitate identifying key medical events in a computerised medical record, and aggregating information across groups of records. The emerging new driver is as the enabler of the life-long computerised medical record. A prerequisite for this level of functionality is the transfer of information between different computer systems. This transfer can be facilitated either by working on the interoperability problems between disparate systems or by harmonising the underlying data. This paper examines the extent to which the latter has occurred across Europe. METHOD: Literature and Internet search. Requests for information via electronic mail to pan-European mailing lists of health informatics professionals. RESULTS: Coding systems are now a de facto part of health information systems across Europe. There are relatively few coding systems in existence across Europe. ICD9 and ICD 10, ICPC and Read were the most established. However the local adaptation of these classification systems either on a by country or by computer software manufacturer basis; significantly reduces the ability for the meaning coded with patients computer records to be easily transferred from one medical record system to another. CONCLUSIONS: There is no longer any debate as to whether a coding or classification system should be used. Convergence of different classifications systems should be encouraged. Countries and computer manufacturers within the EU should be encouraged to stop making local modifications to coding and classification systems, as this practice risks significantly slowing progress towards easy transfer of records between computer systems.

Classification↗
PubMed2001

Physical activity and exercise for women with mobility impairments.

Decisions regarding exercise or physical activity for women with mobility impairments are more complex than those made by other women and by people without mobility limitations. The epidemiologic caveat that being active improves health and well-being generally is applicable, but on the individual level there will be exceptions. For many mobility-limiting conditions, there has been a paucity of research that includes women and even less that focuses specifically on women. Although there is beginning to be evidence that this is changing, there are many unaddressed needs and opportunities for future study.

Attitude to Health↗
PubMed2000

HER2 and choice of adjuvant chemotherapy for invasive breast cancer: National Surgical Adjuvant Breast and Bowel Project Protocol B-15.

BACKGROUND: Recent retrospective analyses have suggested that breast cancer patients whose tumors overexpress HER2 derive preferential benefit from treatment with anthracyclines such as doxorubicin. This has led some clinicians to propose that HER2 should be used as a predictive marker in choosing between anthracycline-based regimens and combination chemotherapy with cyclophosphamide, methotrexate, and 5-fluorouracil (CMF). We evaluated this recommendation in a retrospective study of National Surgical Adjuvant Breast and Bowel Project Protocol B-15, in which patients received a combination of doxorubicin and cyclophosphamide (AC), CMF, or AC followed by CMF. We hypothesized that AC would be superior to CMF only in the HER2-positive patients. METHODS: Immunohistochemical detection of HER2 was performed on tumor sections from 2034 of 2295 eligible patients. We used statistical analysis to evaluate the interaction between the efficacy of the assigned treatments and HER2 overexpression. All statistical tests were two-sided. RESULTS: Tumor sections from 599 patients (29%) stained positive for HER2. AC was superior to CMF in HER2-positive patients only, although differences in outcomes did not reach statistical significance. In the HER2-positive cohort, relative risks of failure (i.e., after AC treatment as compared with CMF treatment) were 0.84 for disease-free survival (DFS) (95% confidence interval [CI] = 0.65--1.07; P =.15), 0.82 for survival (95% CI = 0.63--1.06; P =.14), and 0.80 for recurrence-free survival (RFS) (95% CI = 0.62--1.04; P =.10). Tests for interaction between treatment and HER2 status were suggestive but not statistically significant (P =.19 for DFS, P =.11 for survival, and P =.08 for RFS). CONCLUSIONS: These results, together with overview results indicating minor overall superiority for anthracycline-based regimens relative to CMF, indicate a preference for the AC regimen in patients with HER2-positive tumors. Both AC and CMF regimens may be considered for patients with HER2-negative tumors.

Adult↗
PubMed2000

Development of intermediate-grade (mantle cell) and low-grade (small lymphocytic and marginal zone) human non-Hodgkin's lymphomas xenotransplanted in severe combined immunodeficiency mouse models.

We have used severe combined immunodeficiency (SCID) (c.b.-17, ICR/SCID) mice to develop xenotransplantation (XT) models for human intermediate-and-low-grade non-Hodgkin's lymphomas (NHL). In the past, SCID mice have provided a variety of useful XT models for human hematopoietic neoplasms that primarily involve the acute leukemias and some nonhematopoietic tumors, but only rare reports exist on use of the SCID mouse model in the study of primary tumor cells from NHL. Intermediate-grade and low-grade NHL are the most common lymphomas seen in adults. There is no effective therapy for those types of NHL, and they have not been established in an animal model to date. The lack of an animal model has hampered studies that can evaluate the disease process in vivo as well as the definition of therapeutic parameters involved in treatment. We report in this study that primary patient samples of NHL ( intermediate grade and low grade) have been successfully established in SCID mice after XT. NHL include intermediate-grade (mantle cell lymphoma) and low-grade (eg, small lymphocytic lymphoma/chronic lymphocytic lymphoma and marginal zone lymphoma) forms. Studies have been directed toward creating appropriate conditions for the optimal grafting of these NHL in SCID mice so that the disease process in humans could be accurately simulated. These studies indicate that development of XT-human lymphoma cells in SCID mice appear to be linked to their biologic and/or clinical behavior, transplanted lymphoma cell number, and age, as well as to the natural killer cell status of the SCID mouse recipients. Evidence has also shown that NHL cells can exhibit homing or trafficking patterns in SCID recipients that resemble those observed in patients with gastrointestinal lymphomatous involvement (particularly that of mantle cell lymphoma). Our studies also indicate that artefactual influences, such as the outgrowth of Epstein-Barr virus-associated lymphoblastoid lesions, are rare occurrences in the human NHL/SCID models that we have established.

Adult↗
PubMed2000

Phase 1, randomized, double-blind trial of 7-allyl-8-oxoguanosine (loxoribine) in advanced cancer.

Guanine ribonucleosides substituted at the 8 position of the guanine ring are a unique class of immunomodulators, the lead compound of which is 7-allyl-8-oxoguanosine (loxoribine). We conducted a double-blind randomized phase I study to evaluate the safety, pharmacokinetics, and immunologic effects of single ascending doses of loxoribine in patients with advanced cancer. Twenty-four patients were treated in three dose tiers of 8 patients each, utilizing a unique statistical design, so that within each group, patients were randomized in blocks of 4 to receive loxoribine initially and then placebo 4 weeks later--a sequence that was reversed in the remaining 4 patients. In 23 courses of loxoribine and 20 courses of placebo, toxicity was mild and infrequent at all dose tiers (1 mg/kg, 5 mg/kg and 10 mg/kg. Both antibody-dependent cellular cytotoxicity and lymphokine-activated killer cytotoxicity were transiently depressed following loxoribine administration at all doses. Loxoribine is safe at doses up to 10 mg/kg in patients with advanced cancer, and produces modest immunologic effects. Further testing, particularly in conjunction with other immunologic agents, is warranted.

Adjuvants, Immunologic↗