Showing papers by "University of York published in 1999"

The unbearable automaticity of being

Abstract: What was noted by E. J. hanger (1978) remains true today: that much of contemporary psychological research is based on the assumption that people are consciously and systematically processing incoming information in order to construe and interpret their world and to plan and engage in courses of action. As did E. J. hanger, the authors question this assumption. First, they review evidence that the ability to exercise such conscious, intentional control is actually quite limited, so that most of moment-to-mom ent psychological life must occur through nonconscious means if it is to occur at all. The authors then describe the different possible mechanisms that produce automatic, environmental control over these various phenomena and review evidence establishing both the existence of these mechanisms as well as their consequences for judgments, emotions, and behavior. Three major forms of automatic self-regulation are identified: an automatic effect of perception on action, automatic goal pursuit, and a continual automatic evaluation of one's experience. From the accumulating evidence, the authors conclude that these various nonconscious mental systems perform the lion's share of the self-regulatory burden, beneficently keeping the individual grounded in his or her current environment. The strongest knowledge—that of the total unfreedom of the human will—is nonetheless the poorest in successes, for it always has the strongest opponent: human vanity. —Nietzsche, Human, All Too Human

Impact of formal continuing medical education: do conferences, workshops, rounds, and other traditional continuing education activities change physician behavior or health care outcomes?

Abstract: ContextAlthough physicians report spending a considerable amount of time in continuing medical education (CME) activities, studies have shown a sizable difference between real and ideal performance, suggesting a lack of effect of formal CME.ObjectiveTo review, collate, and interpret the effect of formal CME interventions on physician performance and health care outcomes.Data SourcesSources included searches of the complete Research and Development Resource Base in Continuing Medical Education and the Specialised Register of the Cochrane Effective Practice and Organisation of Care Group, supplemented by searches of MEDLINE from 1993 to January 1999.Study SelectionStudies were included in the analyses if they were randomized controlled trials of formal didactic and/or interactive CME interventions (conferences, courses, rounds, meetings, symposia, lectures, and other formats) in which at least 50% of the participants were practicing physicians. Fourteen of 64 studies identified met these criteria and were included in the analyses. Articles were reviewed independently by 3 of the authors.Data ExtractionDeterminations were made about the nature of the CME intervention (didactic, interactive, or mixed), its occurrence as a 1-time or sequenced event, and other information about its educational content and format. Two of 3 reviewers independently applied all inclusion/exclusion criteria. Data were then subjected to meta-analytic techniques.Data SynthesisThe 14 studies generated 17 interventions fitting our criteria. Nine generated positive changes in professional practice, and 3 of 4 interventions altered health care outcomes in 1 or more measures. In 7 studies, sufficient data were available for effect sizes to be calculated; overall, no significant effect of these educational methods was detected (standardized effect size, 0.34; 95% confidence interval [CI], −0.22 to 0.97). However, interactive and mixed educational sessions were associated with a significant effect on practice (standardized effect size, 0.67; 95% CI, 0.01-1.45).ConclusionsOur data show some evidence that interactive CME sessions that enhance participant activity and provide the opportunity to practice skills can effect change in professional practice and, on occasion, health care outcomes. Based on a small number of well-conducted trials, didactic sessions do not appear to be effective in changing physician performance.

Impact: Toward a Framework for Understanding the Ecological Effects of Invaders

Abstract: Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with large effects in order to prioritize management efforts. This paper focuses on defining, evaluating, and comparing a variety of measures of impact drawn from empirical examples and theoretical reasoning. We begin by arguing that the total impact of an invader includes three fundamental dimensions: range, abundance, and the per-capita or per-biomass effect of the invader. Then we summarize previous approaches to measuring impact at different organizational levels, and suggest some new approaches. Reviewing mathematical models of impact, we argue that theoretical studies using community assembly models could act as a basis for better empirical studies and monitoring programs, as well as provide a clearer understanding of the relationship among different types of impact. We then discuss some of the particular challenges that come from the need to prioritize invasive species in a management or policy context. We end with recommendations about how the field of invasion biology might proceed in order to build a general framework for understanding and predicting impacts. In particular, we advocate studies designed to explore the correlations among different measures: Are the results of complex multivariate methods adequately captured by simple composite metrics such as species richness? How well are impacts on native populations correlated with impacts on ecosystem functions? Are there useful bioindicators for invasion impacts? To what extent does the impact of an invasive species depend on the system in which it is measured? Three approaches would provide new insights in this line of inquiry: (1) studies that measure impacts at multiple scales and multiple levels of organization, (2) studies that synthesize currently available data on different response variables, and (3) models designed to guide empirical work and explore generalities.

Consequences of Automatic Evaluation: Immediate Behavioral Predispositions to Approach or Avoid the Stimulus:

Abstract: Research on automatic attitude activation has documented a pervasive tendency to nonconsciously classify most if not all incoming stimuli as either good or bad. Two experiments tested a functional explanation for this effect. The authors hypothesized that automatic evaluation results directly in behavioral predispositions toward the stimulus, such that positive evaluations produce immediate approach tendencies, and negative evaluations produce immediate avoidance tendencies. Participants responded to attitude object stimuli either by pushing or by pulling a lever. Consistent with the hypothesis, participants were faster to respond to negatively valenced stimuli when pushing the lever away (avoid) than when pulling it toward them (approach) but were faster to respond to positive stimuli by pulling than by pushing the lever. This pattern held even when evaluation of the stimuli was irrelevant to the participants’ conscious task. The automatic classification of stimuli as either good or bad appears to have d...

beta Blockade after myocardial infarction: systematic review and meta regression analysis.

Abstract: Objectives: To assess the effectiveness of β blockers in short term treatment for acute myocardial infarction and in longer term secondary prevention; to examine predictive factors that may influence outcome and therefore choice of drug; and to examine the clinical importance of the results in the light of current treatment. Design:Systematic review of randomised controlled trials. Setting: Randomised controlled trials. Subjects: Patients with acute or past myocardial infarction. Intervention: βBlockers compared with control. Main:outcome measures All cause mortality and non-fatal reinfarction. Results: Overall, 5477 of 54 234 patients (10.1%) randomised to β blockers or control died. We identified a 23% reduction in the odds of death in long term trials (95% confidence interval 15% to 31%), but only a 4% reduction in the odds of death in short term trials (−8% to 15%). Meta regression in long term trials did not identify a significant reduction in effectiveness in drugs with cardioselectivity but did identify a near significant trend towards decreased benefit in drugs with intrinsic sympathomimetic activity. Most evidence is available for propranolol, timolol, and metoprolol. In long term trials, the number needed to treat for 2 years to avoid a death is 42, which compares favourably with other treatments for patients with acute or past myocardial infarction. Conclusions: β Blockers are effective in long term secondary prevention after myocardial infarction, but they are underused in such cases and lead to avoidable mortality and morbidity.

Structure of the Ligand-Binding Domain of Oestrogen Receptor Beta in the Presence of a Partial Agonist and a Full Antagonist

Abstract: Oestrogens exert their physiological effects through two receptor subtypes. Here we report the three-dimensional structure of the oestrogen receptor beta isoform (ERbeta) ligand-binding domain (LBD) in the presence of the phyto-oestrogen genistein and the antagonist raloxifene. The overall structure of ERbeta-LBD is very similar to that previously reported for ERalpha. Each ligand interacts with a unique set of residues within the hormone-binding cavity and induces a distinct orientation in the AF-2 helix (H12). The bulky side chain of raloxifene protrudes from the cavity and physically prevents the alignment of H12 over the bound ligand. In contrast, genistein is completely buried within the hydrophobic core of the protein and binds in a manner similar to that observed for ER's endogenous hormone, 17beta-oestradiol. However, in the ERbeta-genistein complex, H12 does not adopt the distinctive 'agonist' position but, instead, lies in a similar orientation to that induced by ER antagonists. Such a sub-optimal alignment of the transactivation helix is consistent with genistein's partial agonist character in ERbeta and demonstrates how ER's transcriptional response to certain bound ligands is attenuated.

Communicating with calcium

Abstract: ### Calcium as a Ubiquitous Signal in Plants All living cells use a network of signal transduction pathways to conduct developmental programs, obtain nutrients, control their metabolism, and cope with their environment. A major challenge for cell biologists is to understand the “language” of

Efficient anisotropic refinement of macromolecular structures using FFT

Abstract: This paper gives the equations for the use of fast Fourier transformations in individual atomic anisotropic refinement. Restraints on bonded atoms, on the sphericity of each atom and between non-crystallographic symmetry related atoms are described. These have been implemented in the program REFMAC and its performance with several examples is analysed. All the tests show that anisotropic refinement not only reduces the R value and Rfree but also improves the fit to geometric targets, indicating that this parameterization is valuable for improving models derived from experimental data. The computer time taken is comparable to that for isotropic refinements.

Glycosaminoglycans interact selectively with chemokines and modulate receptor binding and cellular responses.

Abstract: Chemokines selectively recruit and activate a variety of cells during inflammation. Interactions between cell surface glycosaminoglycans (GAGs) and chemokines drive the formation of haptotactic or ...

Understanding Policy Transfer: A Multi-Level, Multi-Disciplinary Perspective

Abstract: At the same time that comparative and international political scientists have been confronting the problems of analysing state behaviour under conditions of uncertainty, state-centred political scientists are attempting, somewhat belatedly, to deal with the increasing complexity and uncertainty which underpins modern governance. Yet despite similar research agendas these disciplines have continued to speak past each other. This article contends that policy transfer analysis can provide a context for integrating some key concerns of these disciplines. Further, we argue that the process of policy transfer should be examined through a structure and agency approach with three dimensions: global, international and transnational levels, the macro-level and the interorganizational level. This three-dimensional model employs the notion of a policy transfer network as a middle-range level of analysis which links a particular form of policy development (policy transfer), microdecision making in organizations, macrosystems and global, transnational and international systems. It is hoped that this approach will stimulate an empirical research agenda which will illuminate important policy developments in domestic and world politics.

Dynamics of bed use in accommodating emergency admissions: stochastic simulation model

Abstract: Objective: To examine the daily bed requirements arising from the flow of emergency admissions to an acute hospital, to identify the implications of fluctuating and unpredictable demands for emergency admission for the management of hospital bed capacity, and to quantify the daily risk of insufficient capacity for patients requiring immediate admission. Design: Modelling of the dynamics of the hospital system, using a discrete-event stochastic simulation model, which reflects the relation between demand and available bed capacity. Setting: Hypothetical acute hospital in England. Subjects: Simulated emergency admissions of all types except mental disorder. Main outcome measures: The risk of having no bed available for any patient requiring immediate admission; the daily risk that there is no bed available for at least one patient requiring immediate admission; the mean bed occupancy rate. Results: Risks are discernible when average bed occupancy rates exceed about 85%, and an acute hospital can expect regular bed shortages and periodic bed crises if average bed occupancy rises to 90% or more. Conclusions: There are limits to the occupancy rates that can be achieved safely without considerable risk to patients and to the efficient delivery of emergency care. Spare bed capacity is therefore essential for the effective management of emergency admissions, and its cost should be borne by purchasers as an essential element of an acute hospital service. Key messages Acute hospitals which operate at bed occupancy levels of 90% or more face regular bed crises, with the associated risks to patients Management interventions should focus on measures with long term benefits to counteract the growth trend in demand for admission Many initiatives have only a short term effect; they briefly delay the worst effects but do not address the growing mismatch between supply and demand Evaluating management interventions year on year at a single hospital is futile—any effects are swamped by random variations

Extinction risk in the sea

Abstract: Jean Baptiste de Lamarck and Thomas Huxley, two of the foremost thinkers of the 18th and 19th centuries, believed that humanity could not cause the extinction of marine species. Their opinions reflected a widespread belief that the seas were an inexhaustible source of food and wealth of which people could barely use a fraction. Such views were given weight by the abundant fisheries of the time. Additionally, the incredible fecundity and wide distributions of marine fishes, combined with limited exploitation, provided ample justification for optimism. The ideas of Huxley and Lamarck persist to this day, despite a sea change in the scale and depth of our influence on the oceans. Marine species could be at a far greater risk of extinction than we have assumed.

Health promoting schools and health promotion in schools: two systematic reviews

Abstract: Searching The following databases were searched: ERIC (1980 to 1997), PsycINFO (1980 to 1997), MEDLINE (1966 to 1997), CINAHL (1982 to 1997), ASSIA (1980 to 1997), Sociofile (1974 to 1997), EMBASE (1980 to 1997), and the British Education Index (1980 to 1997). No time or language restrictions were applied. The following databases were searched for 'grey' literature: SIGLE (1980 to 1997), DHSS Data (1980 to 1997), and Dissertation Abstracts (1980 to 1997). The MEDLINE strategy was adapted for use with other databases. Relevant web pages were scanned, including those of the European Network of Health Promoting Schools. Reference lists of retrieved papers were examined to identify further relevant studies. Requests for unpublished data were made to individuals and organisations in the field of health promotion. Bibliographies of identified reviews were scanned for relevant studies. Search terms were listed in an appendix to the main report.

Gender Differences in Population Versus Media Body Sizes: A Comparison over Four Decades

Abstract: Mean body mass indices (BMIs, kg/m2)of North Americans aged 18 to 24 collected from 11national health surveys were compared to: Playboycenterfold models, Miss America Pageant winners,andPlaygirl models. The survey samples were representative of themix of different ethnic and racial groups in Canada andthe USA. No racial or ethnic information was availablefor either the Playboy women or the Miss America Pageant winners. Ninety percent of the Playgirlmen were white; 10%, black; 1.5%, Hispanic black; and.8%, American Samoan. From the 1950s to the present,while the body sizes of Miss America Pageant winners decreased significantly and the body sizes ofPlayboy centerfold models remained below normal bodyweight, the body sizes of Playgirl models and youngadult North American women and men increasedsignificantly. The increase in body size of Playgirl modelsappears to be due to an increase in muscularity, whereasthe increase in body size of young North American menand women is more likely due to an increase in body fat. Thus, in the 1990s, the body size andshape of the average young adult North American becameincreasingly different from the ideal being promoted bythe media. Furthermore the difference in male and female body sizes depicted by the media inthe 1990s was huge, whereas the difference between thebody sizes of 18- to 24-year-old North American womenand men was actually quite small. These discrepancies are discussed in relation to the differentsociocultural expectations for the two genders and theincreasing prevalence of body dissatisfaction reportedby both women and men.

The design of mineralised hard tissues for their mechanical functions.

Abstract: Most hard tissues have as their primary purpose to be stiff. Outside the arthropods, mineralisation of a soft organic matrix is the almost universal method of producing high stiffness. However, stiffening brings with it the undesirable mechanical result of brittleness (lack of toughness). The mineralisation of some tissues, such as bone and dentine, can be modified rather easily, in evolutionary terms, to produce the optimum mix of stiffness with bending strength (which, except at the highest mineralisations, go together) on one hand and toughness on the other hand. However, in most other tissues, such as mollusc shell, echinoderm skeleton, brachiopod shell, barnacle shell and enamel, mineralisation is almost all-or-none, and no subtle gradations seem possible. In such cases, other features, such as architecture, must be modified to produce a useful skeleton. Not only the mechanical properties of the skeletal tissue, but its cost, mass and time taken for production will, biologists tend to assume, be balanced by natural selection to produce a satisfactory result. However, such complexity makes it difficult to be sure that we understand the extent to which mineralised skeletal materials are the best possible solution to the problems facing the animals and that we are not just telling 'Just-So' stories. Furthermore, there are some skeletal materials that do not seem to make much sense at the moment, although no doubt all will become clear eventually.

Randomised controlled trial of exercise for low back pain: clinical outcomes, costs, and preferences

Abstract: Objective: To evaluate effectiveness of an exercise programme in a community setting for patients with low back pain to encourage a return to normal activities. Design: Randomised controlled trial of progressive exercise programme compared with usual primary care management. Patients9 preferences for type of management were elicited independently of randomisation. Participants: 187 patients aged 18-60 years with mechanical low back pain of 4 weeks to 6 months9 duration. Interventions: Exercise classes led by a physiotherapist that included strengthening exercises for all main muscle groups, stretching exercises, relaxation session, and brief education on back care. A cognitive-behavioural approach was used. Main outcome measures: Assessments of debilitating effects of back pain before and after intervention and at 6 months and 1 year later. Measures included Roland disability questionnaire, Aberdeen back pain scale, pain diaries, and use of healthcare services. Results: At 6 weeks after randomisation, the intervention group improved marginally more than the control group on the disability questionnaire and reported less distressing pain. At 6 months and 1 year, the intervention group showed significantly greater improvement in the disability questionnaire score (mean difference in changes 1.35, 95% confidence interval 0.13 to 2.57). At 1 year, the intervention group also showed significantly greater improvement in the Aberdeen back pain scale (4.44, 1.01 to 7.87) and reported only 378 days off work compared with 607 in the control group. The intervention group used fewer healthcare resources. Outcome was not influenced by patients9 preferences. Conclusions: The exercise class was more clinically effective than traditional general practitioner management, regardless of patient preference, and was cost effective. Key messages Patients with back pain need to return to normal activities as soon as possible but are often afraid that movement or activity may be harmful An exercise programme led by a physiotherapist in the community and based on cognitive-behavioural principles helped patients to cope better with their pain and function better even one year later Patients9 preferences for type of management did not affect outcome Patients in the intervention group tended to use fewer healthcare resources and took fewer days off work This type of exercise programme should be more widely available

The role of collagen in the declining mechanical properties of aging human cortical bone.

Abstract: The importance of the mechanical role of collagen in bone is becoming increasingly more clear as evidence mounts on the detrimental effects of altered collagen on the mechanical properties of bone. We previously examined a set of mechanical properties (material stiffness, strength, and toughness) of human femoral bone (ages 35-92) and found that a gradual deterioration in these properties occurs with age. The present study examines the collagen of the same specimens and relates the collagen properties to the mechanical ones. In the collagen we measured the concentration of stable mature crosslinks, the shrinkage temperature, and the rate of contraction during isometric heating. The changes in the concentration of mature (pyridinium and deoxypyridinium) crosslinks showed no clear relationship to age nor did they correlate with the mechanical properties. The shrinkage temperature declined with age and correlated with a bone's toughness. The maximum rate of contraction was strongly correlated with three different measures of tissue toughness, but much less to stiffness and strength. Our results reinforce speculation regarding the toughening role of collagen in bone mechanics and suggest that the fragility of aging bone may be related to collagen changes.

Traffic congestion, driver stress, and driver aggression

Abstract: Automobile drivers were interviewed over cellular telephones in high- and low-congestion conditions during a single commute. During each interview, state measures of driver stress and driver behaviors were obtained. Behavior responses were subdivided into 6 categories: aggressive, information seeking, planning, minor self-destructive, distraction, and relaxation techniques. Both state driver stress and aggression were greater in high- than in low-congestion conditions. No other behavior category differed between low and high congestion. Multiple regressions were calculated to determine predictors of state driver stress. In low congestion, time urgency predicted state driver stress, while aggression predicted driver stress in high congestion. In both conditions, a trait susceptibility toward viewing driving as stressful was predictive of state driver stress levels, further strengthening the use of the Driving Behaviour Inventory--General as a predictor of "trait" driver stress. Females and males did not differentiate on state stress or any behavior category.

Structure of the nucleotide-diphospho-sugar transferase, SpsA from Bacillus subtilis, in native and nucleotide-complexed forms.

Abstract: The enzymatic formation of glycosidic bonds may be catalyzed by the transfer of the glycosyl moiety from an activated nucleotide-diphospho-sugar donor to a specific acceptor. SpsA is a glycosyltransferase implicated in the synthesis of the spore coat of Bacillus subtilis, whose homologues include cellulose synthase and many lipopolysaccharide and bacterial O-antigen synthases. The three-dimensional crystal structure of SpsA has been determined by conventional MIR techniques at a resolution of 1.5 A. It is a two-domain protein with a nucleotide-binding domain together with an acceptor binding domain which features a disordered loop spanning the active site. The structures of SpsA in complex with both Mg-UDP and Mn-UDP have also been determined at 2.0 and 1.7 A, respectively. These complexes, together with the sequence conservation, begin to shed light on the mechanism of this ubiquitous family of inverting glycosyltransferases.

Systematic reviews of wound care management: (2). Dressings and topical agents used in the healing of chronic wounds.

Abstract: Background. Wound dressings are designed to keep the wound clean and free from contamination and also to promote wound healing, particularly in chronic wounds where there may be significant tissue loss. Objectives. This review evaluates the evidence for effectiveness and cost-effectiveness of dressings and topical preparations in pressure sores, leg ulcers and surgical wounds healing by secondary intention. Methods. Nineteen electronic databases, including MEDLINE, EMBASE, CINAHL and the Cochrane Wounds Group's specialised trials register and wound care journals were searched until October 1997. Organisations, manufacturers, researchers and healthcare professionals concerned with wound care were contacted for additional trials. The reference sections of obtained studies were also searched for further trials. Inclusion criteria: Randomised controlled trials (RCTs), published or unpublished, which assessed the effectiveness of a dressing or topical agent in the treatment of pressure sores, leg ulcers, sinuses and surgical wounds healing by secondary intention were included in the review. Where a particular dressing was not evaluated by an RCT, prospective controlled trials were included. Studies were only included if they reported either the proportion of wounds healed within a time period or the percentage or absolute change in wound area. Data extraction and synthesis: Trial data were extracted by one researcher and checked by a second. The results from each study were calculated as odds ratios and/or effect sizes and where appropriate, similar studies have been pooled in a meta-analysis. Results. Surgical wounds healing by secondary intention: Only five studies met the inclusion criteria. All the studies were of poor quality and had small sample size. One study found a statistical benefit for wet-to-dry dressings compared with topical applications of aloe vera. However, neither of these products is commonly used in the UK. Pressure sores: Twenty-eight trials evaluated 31 comparisons of treatments for the healing of pressure sores. The majority of trials were of poor quality. A single report suggested that the topical application of insulin was of significant benefit for wound healing when compared with standard nursing care. A meta-analysis of five reports comparing a hydrocolloid dressing with a traditional treatment suggested that treatment with the hydrocolloid resulted in a statistically significant improvement in the rate of pressure sore healing. Leg ulcers: Sixty studies were included that had evaluated dressings or topical agents in arterial and venous ulcers. Both mononuclear cultured cells in culture medium and topical ketanserin significantly increased healing rates compared with a control preparation in one trial of arterial leg ulcers. Collagen sponges appeared to be effective in two trials of leg ulcers but there were insufficient data to determine the significance of these results. Nine trials compared hydrocolloids with traditional dressings for venous ulcers but meta-analysis demonstrated no significant difference in the proportion of ulcers healed over the trial period. Two trials compared semi-permeable films with traditional dressings; one found a larger reduction in wound area under the film dressing but the other found no significant difference in healing rates. Two trials compared foam dressings and traditional or control therapies; one favoured the foam dressing but the other found no difference between treatments. Woven zinc oxide paste bandage was more effective than either an alginate dressing or a zinc oxide-impregnated stockinette in one trial. In two trials comparing different hydrocolloids, no significant difference in healing rates was found. Comparisons of hydrocolloids with foam dressings found no difference in effectiveness. In trials of topical agents, allopurinol and dimethyl sulfoxide improved healing in one trial compared with inert powder. Of two trials comparing hyaluronic acid with control, one found a difference in daily healing rate and the other found no difference in proportion of ulcers healed over the trial period. Four trials compared biological dressings with traditional therapies. None found statistically significant differences in results. Two trials compared dressings with topical preparations. There was no difference in the proportion of ulcers healed between patients treated with cryopreserved cultured allografts or a hydrocolloid, though the former-treated ulcers had a higher rate of epithelialisation. A collagen dressing was more effective than treatment with daily antiseptic. A comparison of buffered acidifying ointment and ointment reported there was no difference in the proportion of ulcers healed, but there was a higher rate of epithelialisation with the buffered ointment group. In another, trial there were higher healing rates when two amino acid solutions were compared with two groups treated in saline soaks. Publication bias: A funnel plot of all trials showed no evidence of publication bias. However, publication bias was indicated in a comparison of traditional and hydrocolloid dressings. Cost-effectiveness analysis: Nine trials provided data on costs of dressing materials and nursing visits. Six evaluated cost- effectiveness in pressure sore treatments and three papers reported cost- effectiveness data in leg ulcer trials. Conclusions. Implication for practice: There is little evidence to indicate which dressings or topical agents are the most effective in the treatment of chronic wounds. However, there is evidence that hydrocolloid dressings are better than wet-to-dry dressings for the treatment of pressure sores. In the treatment of venous ulcers, low adherent dressings are as effective as hydrocolloid dressings beneath compression bandaging. Recommendations for research: Research methodology could be significantly improved and commissioning groups may wish to consider the following aspects for future research. The number of patients in a trial should be based on an a priori sample size calculation. A truly objective outcome measure should be used or wound healing should be expressed as both percentage and absolute change in area. For each patient a single reference wound should be selected. Experimental groups should be comparable at baseline. Head-to-head comparisons of contemporary dressings are required and should use agents that are recommended for wounds of a similar nature. A complete and thorough description of concurrent treatments, including secondary dressings, should be given in trial reports. Assessment of outcomes should ideally be blind to treatment, or completely objective. Survival rate analysis should be adopted for all studies that assess wound healing. Studies to determine the biological mechanisms involved in wound healing are needed. Future trials should include cost-effectiveness and quality of life assessments, as well as objective measures of dressing performance. Economic evaluations should be incorporated within trials that are sufficiently large to detect appropriate economic and clinical outcomes. To prevent publication bias and ensure the inclusion of unpublished trials in systematic reviews, those involved in primary research should make their data available to those undertaking systematic reviews.

Analysis of apoptosis in the preimplantation bovine embryo using TUNEL.

Abstract: The occurrence of cell death by apoptosis was examined in blastocyst and preblastocyst stage bovine embryos. Zygotes were obtained by in vitro maturation and in vitro fertilization of oocytes from abattoir derived ovaries. Two-cell to hatched blastocyst stage embryos were stained with propidium iodide to label all nuclei and by terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP nick end-labelling (TUNEL) to label apoptotic nuclei, and were analysed by epifluorescent and confocal microscopy. Apoptosis was first observed at the 9-16-cell stage of development, decreasing at the morula stage before increasing at the blastocyst stage. Apoptotic dead cell index in day 7 blastocysts was negatively correlated with the total number of cells; the percentage of dead cells ranged from approximately 1 to 10% and occurred predominantly within the inner cell mass. In addition, apoptotic dead cell index was significantly higher (P < 0.05) in blastocysts cultured (from the two-cell stage) in the presence of 10% fetal bovine serum compared with those developed in serum-free medium. Embryos selected for early cleavage at < 29 h after fertilization and cultured together until the blastocyst stage showed a significantly lower rate of apoptosis (P < 0.01) compared with slower cleaving embryos.