Importance of a healthy environment.
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Air Pollutants↗
Biomedical subjects
A Walker
Publications and source records attributed to A Walker.
Teaching junior doctors practical procedures.
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Clinical Competence↗
Oral contraceptives, androgens, and the sexuality of young women: I. A comparison of sexual experience, sexual attitudes, and gender role in oral contraceptive users and nonusers.
Female undergraduates (108) volunteered for a study of hormones and sexuality, 55 of whom were oral contraceptive (OC) users. In this paper, OC users and nonusers are compared on measures of sexual attitudes and behavior, use of erotic fantasy, and gender role. In the second paper, the effects of OC on androgen levels and the relationship between androgens and behavioral measures within each group are reported. OC users were more likely to have a current sexual partner and less likely to be virgins. The two groups did not differ in frequency of masturbation or use of erotic fantasies. OC users reported less restrictive sexual morality and more interest in erotic images. These differences persisted when women without current partners were excluded. Among those in active sexual relationships, OC users reported more frequent sexual intercourse, higher psychosexual motivation and enjoyment, and were more positive in their evaluation of their partners than OC nonusers.
Adult↗
Oral contraceptives, androgens, and the sexuality of young women: II. The role of androgens.
The relationships between plasma free testosterone (FT) and measures of sexual attitude, sexual behavior, and gender role behavior were assessed in 55 oral contraceptive-using and 53 nonusing female undergraduates. Plasma FT and other measures of androgenicity were substantially lower in the oral contraceptive (OC) group. Correlations between FT and certain behavioral and attitudinal measures were found in the OC users but not the nonusers. In the OC users, FT was positively associated with frequency of sexual intercourse but not with frequency of masturbation. It was negatively associated with restrictive sexual morality. Correlations between FT and measures of gender role behavior were negligible, and FT was unrelated to proceptivity, homosexual interest, or the use of sexual fantasy. The occurrence of some predicted correlations among pill-using women but not the nonusers requires explanation, particularly in view of the substantially lower levels of FT in the pill-using group. It is suggested that androgen-behavior relationships in women are easily obscured by psychosocial influences and in this sample of young women such influences may have been more powerful among those not using OCs. Such psychosocial influences are likely to differ at different stages of women's life cycles. The importance of controlling for such influences in any study of hormone-sexual behavior relationships in women is emphasized, and the need for prospective studies of women before and after starting on steroidal contraception is recognized.
Adult↗
Participation and screening programmes for colorectal cancer: more would be better?
In clinical terms, a screening compliance rate of 100% may be deemed optimal in that the number of abnormalities detected is thereby maximized. This paper explores optimum compliance rates from the cost-effectiveness point of view by modelling the individual's decision to participate in the screening programme. Using data derived from contemporary colorectal screening trials, it assesses the compliance and cost effects of utilizing differing methods of screening invitation, and explores the incremental cost and benefits associated with compliance enhancement techniques. Given the estimated costs and benefits, attempts to attain higher levels of compliance would appear justifiable.
Attitude to Health↗
The cost of screening for colorectal cancer.
STUDY OBJECTIVE: The aim was to make projections of the likely costs and yield resulting from the implementation of a faecal occult blood screening programme for colorectal cancer. DESIGN: Cost and clinical data were derived from the MRC colorectal screening trial currently in progress in Nottingham, UK. SETTING: The above data were used as the basis for modelling the likely implications were the trial to be reproduced as a screening programme within a "typical" family practitioner committee area. MAIN RESULTS: For an average family practitioner committee area with a target population of 75,000 subjects aged 50-74 years, the initial screening round might be expected to detect 85 cancers at a total cost of approximately 250,000 pounds. This represents a cost per cancer detected of 2700 pounds and a cost per person screened of approximately 5 pounds. For subsequent screening rounds, total costs might be expected to fall although average costs are likely to remain approximately constant. CONCLUSIONS: The model is successful in generating "order of magnitude" estimates for the costs of implementation of a screening programme for colorectal cancer. As benefit estimates are not yet available, however, no cost-effectiveness analysis can be undertaken at this stage. In general, sensitivity analyses reveal that programme costs are more sensitive to changes in clinical variables, especially detection and compliance rates, than they are to variations in the costs of resource inputs. A screening programme with a more elaborate protocol than that currently employed in the Nottingham trial will entail considerable cost increases.
Colonic Neoplasms↗
Quantitative assessment of a new dental imaging system.
The "Radiovisiography" dental imaging unit (Trophy UK Ltd) is a digital system using an intensifying screen and charge-coupled device in an intra-oral sensor. This paper presents a description of the system and an assessment of the original model in terms of patient dose (relative to film systems), resolution (limiting resolution and modulation transfer function), distortion and image noise (amplitude). The system does offer the possibility of reduced patient exposure and minimal distortion, although resolution and latitude are inferior to standard dental film.
Humans↗
Influence of protein nutrition on the response of growing lambs to exogenous bovine growth hormone.
Interactions between protein supply and the anabolic response to exogenous bovine (b) GH have been examined in two experiments using 28-35 kg lambs sustained entirely by intragastric infusion of volatile fatty acids (700 kJ/kg W 0.75 per day) into the rumen and the casein (600 mg (low protein; LP) or 1200 mg (high protein; HP)/kg W 0.75 per day) into the abomasum. Sheep received continuous i.v. infusions of bGH for 6 days in experiment 1 and for 18 days in experiment 2. Nitrogen balances were determined daily throughout both experiments and blood samples, from indwelling catheters, were assayed for GH, insulin-like growth factor-I (IGF-I), insulin and glucose. Infusion of bGH increased plasma GH concentration by five- to sixfold in all animals. There was an increase in N retention in both HP and LP animals over the first 2-3 days of GH administration. HP animals sustained higher N retentions (31%; P less than 0.05) throughout the GH administration but LP animals did not. In contrast, plasma IGF-I concentrations increased progressively over the first 72 to 96 h of GH administration in all sheep and thereafter remained significantly (P less than 0.05) elevated until termination of the GH infusion. In lambs which received both HP and LP infusion in experiment 1 the increase in IGF-I and LP infusions in experiment 1 the increase in IGF-I concentration by day 6 of GH administration was significantly (P less than 0.05) greater when they received the higher protein intake.(ABSTRACT TRUNCATED AT 250 WORDS)
Animal Nutritional Physiological Phenomena↗
Autocrine growth factors and solid tumor malignancy.
The ability of malignant cells to escape the constraint that normally regulate cell growth and differentiation has been a primary focus of attention for investigators of cancer cell biology. An outcome of this attention has been the discovery that the protein products of oncogenes play a role in the activation of growth signal pathways. A second outcome, possibly related to abnormal oncogene expression, has been the discovery that malignant cells frequently show an ability to regulate their own growth by the release of autocrine growth modulatory substances. Most important, the growth of certain malignant cell types has been shown to depend on autocrine growth circuits. A malignant tumor whose continued growth depends on the release of an autocrine growth factor may be vulnerable to treatment with specific receptor antagonists or immunoneutralizing antibodies designed to break the autocrine circuit. Information is rapidly emerging concerning autocrine growth factors in selected human solid tissue malignancy.
Cytokines↗
Tale of two hospitals.
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Costs and Cost Analysis↗
Modelling soil productivity and pollution.
Predictive models of soil and plant processes should be of much benefit both in developing and developed countries. They can assist in enabling agronomic practices to be better adjusted for differences in conditions; in avoiding disasters that can accompany change in land use; in minimizing waste and environmental pollution, and in modifying and implementing legislation. These views are discussed in the light of recent advances. Particular attention is drawn to (i) the excellent relationships linking average national yields, nutrient uptakes, etc. to single factors such as average fertilizer application; (ii) equations for predicting the behaviour of added chemicals and water in soil that have been obtained by rigorous deduction from physical and chemical laws; (iii) the discovery of semi-empirical, but nevertheless widely applicable quantitative relations for key soil and plant processes, and (iv) the formulation and use of computer models for field situations. There is a pressing need to find ways of presenting the outcome of this work so that it can be more widely applied in practice.
Agriculture↗
AIDS funding falls.
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Acquired Immunodeficiency Syndrome↗
Survival of the older patient compared with the younger patient with Hodgkin's disease. Influence of histologic type, staging, and treatment.
Age as an independent risk factor for survival of Hodgkin's disease (HD) was investigated using data for the 6345 patients in the American College of Surgeons, Patterns of Care Study. Patients were divided into those 15 to 34 years of age, and those older than 50 years. Older patients had higher rates of advanced stage and B symptoms (e.g., Stage IVB, 19.7% compared with 7.7%) and significantly higher rates of poor prognosis histologic types, odds ratio (OR) = 3.7. The older population with clinical stage (CS) I and II disease was also less likely to have received any of the selected staging procedures, bone marrow biopsy, lymphogram, or laparotomy (OR = 4.48). The two populations were equivalently understaged when CS was compared with pathologic stage (PS). In each category the older patients were more likely to have received no therapy; for PS I and II disease the OR for older patients compared with the younger patient was 2.14. When stratified by PS, B symptom status, histologic type, and treatment the older patients continued to show poorer 5-year survival by the life-table method. The authors' hypothesis--that older patients equivalently staged and treated would have no significant difference in long-term survival--was not substantiated by the data. However, in the analyses in which corrections for the known risk factors were made, the difference in survival was not as great as that in the crude, unstratified data. This study, as well as other recent studies utilizing smaller numbers of patients, finds age an independent predictor of poorer survival in HD patients.
Adolescent↗
Radiovisiography: an initial evaluation.
An initial evaluation of the latest dental radiographic imaging system, radiovisiography, is reported. Despite limitations in its possible clinical applications and problems inherent within the system design, radiovisiography has been found to be a rapid imaging system capable of producing clinically acceptable periapical images. It is suggested that this system may be of particular value in endodontics and in its present form should be considered as an adjunct rather than as a replacement for conventional intra-oral film. Further studies are now required into recent system modifications which are described.
Adolescent↗
Birthweight percentiles for aborigines?
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Birth Weight↗
Genetic diversity of Plasmodium falciparum shows geographical variation.
Sixty Plasmodium falciparum isolates, 20 each from Thailand, Zimbabwe, and Brazil, were characterized for 20 variant genetic markers, including the enzymes glucose phosphate isomerase, adenosine deaminase and peptidase, 11 other proteins detected by 2-dimensional electrophoresis (2D-PAGE), 2 merozoite surface antigens (MSA-1 and MSA-2), one exported antigen (Exp-1), and sensitivity to the drugs chloroquine, pyrimethamine, and mefloquine. The study examines the extent of diversity between individual isolates and the differences in the frequency of certain variants of the markers between the 3 countries. The principal conclusions to be drawn from the study are that there is extensive polymorphism in many of the genetically determined characters of this parasite, multiple infections with greater than 1 genetically distinct parasite are common, and there are geographical variations in the frequencies with which variant forms of certain markers occur.
Alleles↗