PubMed Health⌕ Search

Biomedical subjects

J Weeks

Publications and source records attributed to J Weeks.

At least 19 recordsLinked to original sources
PubMed1996

Economic analyses in health care: an introduction to the methodology with an emphasis on radiation therapy.

Payers are increasingly interested in knowing whether they are receiving value for the dollars they spend on health care. Because economic analysis will be used as a means of evaluating radiation therapy, it is important that radiation oncologists understand the basic methodology employed in such analyses. This review article describes the four basic types of economic analyses: cost minimization, cost effectiveness, cost utility, and cost benefit. Specification of alternative therapies, choice of perspective of the analysis, measurements of costs and benefits, and the role of discounting and sensitivity analyses are discussed. Published economic analyses that pertain directly to treatment with radiation therapy are reviewed. Finally, we close with a brief discussion of the potential areas for future economic outcomes research in radiation oncology.

Cost-Benefit Analysis↗
PubMed1996

Lack of evidence of nosocomial cross-infection by Burkholderia cepacia among Danish cystic fibrosis patients.

Burkholderia cepacia isolates from nine of the ten Danish cystic fibrosis (CF) patients known between 1975 and the present day to carry this organism were investigated. Eight distinct genotypes were found with polymerase chain reaction ribotyping and pulsed-field gel electrophoresis. The results indicate that there is little patient-to-patient cross-infection with Burkholderia cepacia within the Danish CF population, even though the majority of patients attend the same CF clinic on a regular basis.

Burkholderia Infections↗
PubMed1996

Comparative effects of propofol, pentobarbital, and isoflurane on cerebral blood flow and blood volume.

While intravenous and volatile anesthetics have widely differing effects on cerebral blood flow (CBF), clinical studies suggest that the relative differences in their effects on intracranial pressure (ICP) may be smaller. Because acute changes in ICP are determined primarily by changes in cerebral blood volume (CBV), we compared the impact of propofol, pentobarbital, and isoflurane on CBF and CBV in rats. Equipotent doses of the three agents were determined by tail-clamp studies. Animals were then anesthetized with propofol (20 mg/kg load, 38 mg.kg-1.h-1 infusion), pentobarbital (30 mg/kg load, 20 mg.kg-1.h-1 infusion), or isoflurane 1.6-1.8%. Two hours later, CBF and CBV were measured using 3H-nicotine as a CBF tracer, and 14C-dextran and 99mTc-labeled red cells as markers for cerebral plasma and red blood cell volumes (CPV and CRBCV), respectively. Total CBV was the sum of CPV and CRBCV. CBF was 2.0-2.6 times greater with isoflurane than with propofol or pentobarbital (137 vs. 67 and 52 ml.100 g-1.min-1, respectively). By contrast, while CBV was greater in the isoflurane group than in either the propofol or pentobarbital groups, the magnitude of the intergroup differences were much smaller (propofol = 2.49 +/- 0.28 ml/100 g; pentobarbital = 2.27 +/- 0.15 ml/100 g; isoflurane = 2.77 +/- 0.24 ml/100 g, mean +/- SD). These results suggest that the simple measurement of CBF may not adequately describe the cerebrovascular effects of an anesthetic, at least with respect to predicting the magnitude of the agents likely effects on ICP.

Adjuvants, Anesthesia↗
PubMed1996

Leukemia following low-dose total body irradiation and chemotherapy for non-Hodgkin's lymphoma.

PURPOSE: Low-dose total body irradiation (TBI) is used to treat non-Hodgkin's lymphoma (NHL) and several other malignancies. Large volumes of bone marrow and other tissue receive considerable exposure, but few studies have quantified late carcinogenic sequelae. PATIENTS AND METHODS: A cohort of 61 2-year survivors of NHL treated initially with low-dose TBI was monitored for second cancer occurrence. Data on primary and subsequent therapy were collected, and cumulative dose of radiation to active bone marrow (ABM) (median, 5.2 Gy) was reconstructed. RESULTS: Thirteen second primary cancers occurred. Four patients developed acute nonlymphocytic leukemia (ANLL), which represents a relative risk (RR) of 117 (95% confidence interval [CI], 31.5 to 300) compared with population rates. A fifth patient was diagnosed with myelodysplastic syndrome (MDS). All five patients with secondary hematologic malignancies subsequently received salvage treatment, with either alkylating agents alone (n = 1) or combined modality therapy (CMT) (n = 4). Overall, eight solid tumors were observed (RR = 2.0; 95% CI, 0.9 to 4.0). The 15-year cumulative risks of all second cancers and secondary ANLL were 37% and 17%, respectively. CONCLUSIONS: Despite the small number of subjects, a considerable risk of leukemia was observed among patients treated with low-dose TBI in combination with CMT including alkylating agents. Based on these results, approximately eight to nine excess ANLLs might be expected to occur among 100 NHL patients treated with low-dose TBI and salvage treatment and followed-up for 15 years.

Adolescent↗
PubMed1996

The respiratory effects of reduction of mite allergen in the bedrooms of asthmatic children--a double-blind controlled trial.

BACKGROUND: Inhalation of house dust mite (HDM) allergen may provoke attacks of asthma. OBJECTIVE: We investigated whether a double-blind placebo-controlled community-based study aimed at reducing the HDM allergens in the bedrooms of HDM sensitive asthmatic children using the best methods available would prove beneficial to the children's health. METHODS: The children (mean age 9.9 years, 34 boys) were recruited by a questionnaire submitted to 7386 families in a geographically-defined area of the UK. Subjects were chosen to take part in the double-blind placebo-controlled trial if they were asthmatic, skin sensitive to mites, and had mite allergen in their mattresses. Seventy children were randomly allocated to groups. In the active group, the children's bedrooms were treated with an acaricide (Acarosan) and the mattresses, pillows and duvets were encased in exclusion covers. The control group received placebo treatments. RESULTS: Forty-nine complete data sets were obtained. Applying bedding covers and Acarosan led to a median reduction of 480 ng (100%) in mite allergen on the mattress vs 215 ng (53%) reduction in placebo-treated group by 6 weeks. No evidence was found that the acaricide reduced mite allergen level. A change in bronchial reactivity to histamine was observed in the children after 6 weeks. This was not associated with any change in thrice-daily records of peak expiratory flow rate. By 24 weeks, the actively-treated children had improved forced expiratory volume in 1s (FEV1) and fewer required bronchodilator therapy or reported asthmatic symptoms than did the controls. CONCLUSIONS: The results suggest that mite removal procedures may modestly improve mite-sensitive asthmatics and could perhaps be of value in exceptionally mite-sensitive and/or highly mite-exposed individuals whose response to the attempted removal should be measured.

Allergens↗
PubMed1996

Taking quality of life into account in health economic analyses.

Cost-utility analysis is the most commonly used approach to incorporating quality-of-life considerations into economic analyses in health care. This type of analysis produces a ratio of the incremental cost of one intervention over another to the incremental benefit produced, measured in quality-adjusted life years. To be suitable for use in calculating quality-adjusted survival, quality of life must be measured in the form of a utility. Direct utility assessment techniques are grounded in decision analytic theory and are conceptually complex and impractical for use in the clinical trial setting. Alternatives include global rating scale items with appropriate "transformations" and health state classification indices. The first cancer trials to collect economic data and utilities from patients using these techniques are now under way. These trials will serve to answer not only biological questions, but also health policy questions about whether the additional cost of the more expensive therapy is justified by the benefit it produces in both length and quality of life.

Clinical Trials as Topic↗
PubMed1996

Outcomes research studies.

The outcomes movement has its roots in studies conducted in the 1970s and '80s, which showed that there was substantial geographic variability in medical practice in the United States and that such variability was driven by nonmedical factors. Outcomes management has several key components: the development and implementation of guidelines; measurement, pooling, and dissemination of clinical and outcomes data; and refinement of guidelines based on analysis of those data. Cancer has lagged behind many other areas of medicine in pursuing outcomes research and management. The National Comprehensive Cancer Network (NCCN) has made a commitment to perform outcomes research within its member institutions and has begun to pool and analyze selected patterns of care and outcomes data. The network's ultimate goal is the creation of a uniform outcomes measurement system to monitor guideline compliance.

Humans↗
PubMed1995

Umbilical artery occlusion and fetoplacental thromboembolism.

BACKGROUND: To our knowledge, fetoplacental thromboembolism has been described only in autopsy specimens. We report the antepartum diagnosis of an umbilical artery occlusion and neonatal diagnosis of an aortic thrombus and placental emboli. CASE: A gravida at 31 weeks' gestation was referred for evaluation of decreased fetal movement and an enlarged fetal bladder. A two-vessel umbilical cord with a collapsed, echogenic third vessel was noted, whereas views of a normal three-vessel cord were available from an examination 5 weeks earlier. A positive oxytocin contraction test prompted delivery. Neonatal color flow Doppler imaging demonstrated an aortic thrombus below the renal arteries and above the bifurcation. Gross and microscopic study of the placenta demonstrated necrosis of the collapsed umbilical artery and numerous placental emboli. The aortic thrombus resolved gradually, and the infant went home on the 39th day of life. CONCLUSION: Umbilical artery occlusion can be diagnosed ultrasonographically and may be a sign of fetoplacental thromboembolism. Assessment of fetal oxygenation status by biophysical profile or contraction stress test may be helpful in the evaluation of umbilical artery occlusion.

Abortion, Threatened↗
PubMed1995

Characterisation of Burkholderia cepacia from cystic fibrosis patients living in Wales by PCR ribotyping.

Polymerase chain reaction (PCR) ribotyping detects differences in the intergenic spacer between the 16S and 23SrRNA genes. This method was applied to Burkholderia cepacia isolates from 16 Welsh cystic fibrosis (CF) patients attending three different clinics. Amplification of the intergenic spacer followed by an additional digestion step with TaqI restriction endonuclease identified seven distinct electrophoretic patterns among the patient isolates. Each of the seven patterns was distinct from that of the so called "epidemic strain" commonly isolated from patients attending clinics elsewhere in the UK. Two environmental isolates from the hospital clinics and four NCTC reference strains gave different patterns. The simplicity of the method lends itself to use in a general microbiological laboratory.

Base Sequence↗
PubMed1995

A combined approach to reduce mite allergen in the bedroom.

BACKGROUND: Asthma is a common chronic disease of childhood. House dust mite (HDM) are known to be a major source of allergen affecting atopic asthmatics. No single control method has been demonstrated to consistently reduce asthma. OBJECTIVE: We investigated the effect of a combination of two methods of HDM allergen control on HDM allergen content in the bedding and carpets of asthmatic children. METHODS: This was a double-blind placebo-controlled trial treating the bedrooms of 56 mite-sensitive asthmatic children. The carpet and the mattress, duvet and pillows (bedding) in the bedroom of children of the active group were treated with the acaricide Acarosan (benzyl benzoate). The bedding was then encased in vapour permeable waterproof fabric (Intervent--cotton coated with polyurethane) for 24 weeks. The carpet and bedding of the control group were treated with placebo and the bedding encased in cotton covers for 24 weeks. Dust samples were collected from all these items in a standard manner at regular intervals and Der p I content analysed. RESULTS: The group with active treatment had a median reduction of 480 ng (100%) in mite allergen from the mattress vs 215 ng (53%) reduction in placebo-treated group by 6 weeks. The Der p I content of the active group's bedding was always less than the placebo group after treatment (P < 0.01). The acaricide applied to the carpets or inside the mattress covers was ineffective in reducing allergen content. CONCLUSION: This study confirms the effectiveness of encasing covers in reducing the mite allergen exposure but indicates there is no further advantage in applying acaricide simultaneously.

Allergens↗
PubMed1995

Measurement of utilities and quality-adjusted survival.

Quality-adjusted survival as a measure of the effectiveness of medical interventions captures the tradeoffs between length and quality of life that are often involved in choosing between alternative treatment strategies. Until recently, the utilities needed to calculate quality-adjusted survival were generally estimated by experts; however, there is growing interest in collection of empiric utility data in the clinical trial and clinical practice settings. The classic approaches to direct utility assessment are difficult to administer and have questionable psychometric properties. Health state classification indices offer a promising alternative approach that relies on patients as the source of information regarding the health-related quality of life impact of a given health state while providing utility estimates suitable for guiding treatment and resource allocation decisions.

Humans↗
PubMed1994

Educational interventions and the use of parenteral nutrition.

The Georgetown Total Parenteral Nutrition Forum generated consensus statements about the need for nutrition support. The main concern is that the excessive use of parenteral nutritional is both dangerous and expensive. We performed confidential audits using these criteria before and after educational interventions. The incidence of doubtful usage decreased from 29% (8/28) in mid-1991 to 3% (1/30) in mid-1992 (Fisher Exact Probability = 0.01): A post-audit review one year later in mid-1993 revealed an incidence of doubtful usage of 0% (0/19). It is concluded that the consensus document from the Georgetown Parenteral Nutrition Forum is a useful tool for deriving usage guidelines, educating staff and performing criterion audits. In this way, it is possible to generate cost savings and improve the quality of care.

Australia↗
PubMed1993

Mapping mutations in genes encoding the two large subunits of Drosophila RNA polymerase II defines domains essential for basic transcription functions and for proper expression of developmental genes.

We have mapped a number of mutations at the DNA sequence level in genes encoding the largest (RpII215) and second-largest (RpII140) subunits of Drosophila melanogaster RNA polymerase II. Using polymerase chain reaction (PCR) amplification and single-strand conformation polymorphism (SSCP) analysis, we detected 12 mutations from 14 mutant alleles (86%) as mobility shifts in nondenaturing gel electrophoresis, thus localizing the mutations to the corresponding PCR fragments of about 350 bp. We then determined the mutations at the DNA sequence level by directly subcloning the PCR fragments and sequencing them. The five mapped RpII140 mutations clustered in a C-terminal portion of the second-largest subunit, indicating the functional importance of this region of the subunit. The RpII215 mutations were distributed more broadly, although six of eight clustered in a central region of the subunit. One notable mutation that we localized to this region was the alpha-amanitin-resistant mutation RpII215C4, which also affects RNA chain elongation in vitro. RpII215C4 mapped to a position near the sites of corresponding mutations in mouse and in Caenorhabditis elegans genes, reinforcing the idea that this region is involved in amatoxin binding and transcript elongation. We also mapped mutations in both RpII215 and RpII140 that cause a developmental defect known as the Ubx effect. The clustering of these mutations in each gene suggests that they define functional domains in each subunit whose alteration induces the mutant phenotype.

Amino Acid Sequence↗
PubMed1990

Quality of life in cancer patients: clinical considerations and perspectives.

Maintaining "quality of life" for a cancer patient is analogous to caring for the "whole" patient. Such care should include integration of multispecialty services, on-going patient education, attention to supportive care, and efforts to achieve organ preservation. Also to be taken into account are such factors as the extraordinarily heterogeneous backgrounds of cancer patients, the degree of involvement of the patient's family, and the financial implications of cancer and its treatment. These considerations require the primary physician and the rest of the care team to individualize their approach to each patient. All medical personnel must also realize that effective, honest communication may improve quality of life, even in those patients whose medical conditions are the poorest.

Attitude to Health↗