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Biomedical subjects

R Thomson

Publications and source records attributed to R Thomson.

At least 19 recordsLinked to original sources
PubMed2001

A giant multiacinar macroregenerative nodule in an explanted liver.

Macroregenerative nodules (MRN) have been detected with increased incidence in explanted livers since orthotopic liver transplantation (OLTx) has become a routine treatment for end-stage liver disease. Autopsy series suggest that MRN may be more common than once thought, and several studies point to the malignant potential of these lesions. With increasing waiting times for OLTx, the propensity for these premalignant lesions to arise in cirrhotic livers has important implications for the supervision of patients on OLTx waiting lists. We present here a striking example of a MRN and review a topic that is generating considerable interest.

Adult↗
PubMed2001

A novel method for the isolation of motile bacteria using gradient culture systems.

Isolation of motile bacteria from stream water samples was achieved by using Lutrol F127 (poloxamer 407) as a gelling agent in culture media. This block copolymer has the property of repeatedly liquefying and solidifying at low and high temperatures, respectively. The ability of motile bacteria to move through liquid-state Lutrol F127 towards a higher nutrient concentration was exploited. After establishment of the nutrient gradient and inoculation, the system was cooled to liquefy the medium and kept liquid to allow motile bacteria to move. Raising the temperature allowed solidification and prevented further movement. Colonies could be easily removed. The proportion of motile isolates (determined by microscopic observation) increased from 42% in the indigenous population to 100% after isolation using the gradient system.

Bacteria↗
PubMed2001

Implementation and evaluation of local-level priority setting for stroke.

We aimed to develop and evaluate a prioritisation process to combine the evidence base with stakeholder involvement within a stroke programme for a Health Improvement Programme (HImP). Implementation involved: formation of a district stroke group (DSG); review of the evidence; survey of DSG members; survey of other key professionals; consensus within the DSG; consultation with local users of the service. Evaluation was through semi-structured interviews and documentary analysis. The process was accepted as appropriate and valuable by the majority of participants, and a district HImP implementation group allocated pound sterling 100 000 for stroke development as a result of this process. However, some felt that stroke itself had been an imposed, rather than an agreed, local priority. The priority setting process was not clear to all participants and change of personnel, particularly in the NHS trusts, led to some perceived lack of ownership. Professionals from secondary care participated, but later criticised the process when they felt that the priorities in the HImP could limit their ability to access money for other service developments. The user consultation days occurred too late to influence the 1999/2002 HImP. We have shown that it is possible to develop an approach that is broadly accepted by stakeholders and balance the evidence base with local ownership. The participation of stakeholders, clarity of procedures, local ownership and awareness of local politics are important in effective priority setting. The model developed will be of value in other settings.

Evidence-Based Medicine↗
PubMed2001

Where is the gender in gendered language?

The purpose of these studies was to examine how women and men react and accommodate to gender-preferential language in e-mail messages. In Experiment 1, participants wrote messages to two assigned "netpals." These netpals were actually one of the experimenters. For each participant, one netpal used female-preferential language and the other used male-preferential language. Analyses revealed that the netpals' language style, and not the participants' gender, predicted the language used by participants in their e-mail replies. Female and male participants used the gender-preferential language that matched the language used by their netpals. In Experiment 2, the gender labels and language styles of netpals were independently manipulated. As before, linguistic style had the greatest impact on participants' language use. These results have implications for how people think about gendered behavior, and highlight how gendered language is constructed in social interaction.

Adult↗
PubMed2001

Variability in patient preferences for participating in medical decision making: implication for the use of decision support tools.

While there is an increasing emphasis on patient empowerment and shared decision making, evidence suggests that many patients do not wish to be involved in decisions about their own care. Previous research has found patient preferences for involvement in decision making to vary with age, socioeconomic status, illness experience, and the gravity of the decision. Furthermore, there is evidence that certain patients may experience disutility from being involved in decision making about the treatment of their health problems. We discuss the implications of these findings for the use of decision support tools and the difficulties of targeting their use towards those patients most likely to benefit. We argue that patients may be ill informed about what participation in decision making actually entails and unaware of the benefits they stand to gain by articulating their preferences to their clinician. Furthermore, clinicians are not good at accurately assessing patients' preferences, while patients may have unrealistic expectations about their clinician's ability to "know what is best" for them. Further research is required to understand variations in patients' preferences for information and involvement in decision making, and the factors that influence them.

Communication↗
PubMed2001

How patients with atrial fibrillation value different health outcomes: a standard gamble study.

BACKGROUND AND PURPOSE: The assessment of any health care intervention should consider both risks and benefits and take patients' preferences about these into account. The study reported in this paper aimed to elicit patient valuations of health states relevant to assessment of the prevention of stroke by warfarin anticoagulation therapy for patients with atrial fibrillation. METHODS: A sample of patients over the age of 60 years with atrial fibrillation from three family practices in North-East England was interviewed. Their health state values were elicited using the standard gamble method for general practitioner (GP)-managed warfarin treatment, hospital-managed warfarin treatment, major bleed, mild stroke and severe stroke. RESULTS: Of 180 patients, 69 (38%) agreed to participate, of whom 57 (83%) completed interviews. Median (mean) utility values were for GP-managed warfarin treatment 0.986 (0.948), hospital-managed warfarin treatment 0.984 (0.941), major bleed 0.880 (0.841), mild stroke 0.675 (0.641) and severe stroke 0 (0.189). There was wide variation in values between patients and the distributions were highly skewed. CONCLUSIONS: The results are of value in applying decision analysis to groups of patients. They should be used with caution in reaching decisions about appropriate treatment for individual patients, but may provide a starting point for necessary further exploration of those patients' individual preferences.

Anticoagulants↗
PubMed2001

Predicting gender from electronic discourse.

There is substantial evidence of gender differences in face-to-face communication, and we suspect that similar differences are present in electronic communication. We designed three studies to examine gender-preferential language style in electronic discourse. In Expt 1, participants sent electronic messages to a designated 'netpal'. A discriminant analysis showed that it was possible to successfully classify the participants by gender with 91.4% accuracy. In Expts 2 and 3, we wanted to determine whether readers of e-mails could accurately identify author gender. We gave participants a selection of messages from Expt 1 and asked them to predict the author's gender. It was found that for 14 of the 16 messages used, the gender of author was correctly predicted. In the third experiment, six messages about gender-neutral topics were composed. Using a subset of the variables identified in Expt 1, female and male versions of each message were created. When participants were asked to rate whether a female or a male wrote these messages, their ratings differed as a function of the message version. These findings establish that people use gender-preferential language in informal electronic discourse. Furthermore, readers of these messages can use these gender-linked language differences to identify the author's gender.

Adolescent↗
PubMed2001

Medical decision support via the internet: PROforma and Solo.

This paper describes the development and application of an integrated technology to support the authoring of intelligent medical knowledge services, such as decision and guideline support, and disseminate them over the Internet. Decision support and guideline enactment are provided by the PROforma technology which is described in detail elsewhere. Solo is a communications infrastructure that supports the delivery of PROforma services over the Internet using a web browser. The PROforma-Solo technology brings together techniques from knowledge engineering and artificial intelligence with software engineering and the Internet to flexibly support decision making and patient management at the point of care. A variety of clinical applications have been implemented and are briefly described.

Artificial Intelligence↗
PubMed2000

Recent common ancestry of human Y chromosomes: evidence from DNA sequence data.

We consider a data set of DNA sequence variation at three Y chromosome genes (SMCY, DBY, and DFFRY) in a worldwide sample of human Y chromosomes. Between 53 and 70 chromosomes were fully screened for sequence variation at each locus by using the method of denaturing high-performance liquid chromatography. The sum of the lengths of the three genes is 64,120 bp. We have used these data to study the ancestral genealogy of human Y chromosomes. In particular, we focused on estimating the expected time to the most recent common ancestor and the expected ages of certain mutations with interesting geographic distributions. Although the geographic structure of the inferred haplotype tree is reminiscent of that obtained for other loci (the root is in Africa, and most of the oldest non-African lineages are Asian), the expected time to the most recent common ancestor is remarkably short, on the order of 50,000 years. Thus, although previous studies have noted that Y chromosome variation shows extreme geographic structure, we estimate that the spread of Y chromosomes out of Africa is much more recent than previously was thought. We also show that our data indicate substantial population growth in the effective number of human Y chromosomes.

Biological Evolution↗
PubMed2000

Decision analysis and guidelines for anticoagulant therapy to prevent stroke in patients with atrial fibrillation.

BACKGROUND: Clinical guidelines are needed on whether or not to use anticoagulant therapy to prevent stroke in patients with non-valvular atrial fibrillation. We did a Markov decision analysis to model decision-making with regard to warfarin treatment in patients with atrial fibrillation, and used the model to develop evaluative guidelines. METHODS: The decision analysis involved a systematic literature review supplemented by patients' estimates of the quality of life associated with different states of health, secondary analysis of stroke-registry data, and estimation of service costs; it also incorporated a sensitivity analysis. The derived guidelines were subsequently applied to a cohort of patients with atrial fibrillation. FINDINGS: We constructed decision tables for 12 age and sex groups. For most risk combinations, warfarin treatment would have decreased health-care costs and increased quality-of-life years, although the clinical decision was sensitive to patients' preferences and to the estimate of warfarin's effectiveness. 97% of women with atrial fibrillation older than 75 years, and 69% aged 65-74 would have been recommended for treatment; for men, the corresponding figures would have been 75% and 53%. With the upper quartile for the loss of quality of life associated with being on warfarin treatment (1.00), all but two of the 116 patients without contraindications would have been treated, whereas with the lower quartile (0.92), only 27 of 116 would have been treated. INTERPRETATION: Decision analysis is useful in the incorporation of complex probabilistic data into informed decision-making, the identification of factors influencing such decisions, and the subsequent development of evaluative guidelines.

Aged↗
PubMed2000

Decision analysis in evidence-based decision making.

Many real world decisions have to be made on a limited evidence base, and clinical decisions are at best problematic. We explored some of the reasons why decision making in health care is so complex, and examined how decision analytic techniques might contribute to problem structuring and to implementation of evidence-based practice. We argued that decision analysis could, to some extent, overcome complexity of decision making by a clear structuring of the problem and a formal analysis of the implications of different decisions. Decision-analytic techniques can guide the management of individual patients or can be used to address policy questions about the use of treatment for groups of patients. However, decision analysis is not without its criticisms, e.g. problems are narrowly defined, replacing judgement and dehumanizing care, neglect of process utility and lack of primary data to develop decision analytic models. The development of evidence-based guidelines is a key component of the UK Government's quality strategy led by the National Institute for Clinical Excellence (NICE). However, the guidelines approach may lead to conflict when assessments of the effectiveness of interventions for individuals (whether or not supported by a formal decision analysis) conflict with the recommendations made by NICE for cost and clinical effectiveness for aggregate groups of patients. Decision analysis may or may not help with this but if guidelines are derived from a decision analysis, then the implications of patient preferences should be made clearer. However, decision analysis-derived guidelines will make general recommendations that may not be appropriate for all individuals. Nonetheless, decision analysis does make such implications explicit and propose that the guidelines should be supported by some mechanism for determining individual patient preferences. It will now need to consider whether some of NICE resources should be directed beyond evidence-based guidelines into decision analysis-derived guidelines and into decision analytical techniques to provide support for clinical and cost effective decision making within the patient-clinician encounter.

Decision Making↗
PubMed2000

What do medical students read and why? A survey of medical students in Newcastle-upon-Tyne, England.

OBJECTIVES: There is increasing interest in the role of medical humanities within the undergraduate curriculum, but we know little about medical students' views on this or about their reading habits. Our study explored the reading habits of medical students, and their attitudes towards literature and the introduction of humanities into the curriculum. DESIGN: Self-completion questionnaire survey. SETTING: Newcastle University and Medical School. SUBJECTS: All first-, second- and third-year undergraduate medical students (384), biology students (151) and a random sample of law students (137) were sent a self-completion questionnaire to assess reading levels, attitudes towards literature and the medical humanities (medical students) and the perceived benefits of reading. RESULTS: Medical students read widely beyond their course and articulate a range of benefits from this, including: increasing awareness of life outside their experience; introspection or inspiration; emotional responses; and stimulation of an interest in reading or literature. Of the medical students, 40% (103/258) read one or more fiction books per month, but 75% (193) read fewer non-curricular books since starting university, largely because of time pressures, work, study or academic pressures and restricted access to books. A total of 77% (194) thought that medical humanities should definitely or possibly be offered in the curriculum, but of these 73% (141) thought it should be optional and 89% (172) that it should not be examined. CONCLUSIONS: Medical students read literature for a variety of very positive and valued reasons, but have found leisure reading harder to maintain since starting university. They support inclusion of the humanities in medical education, but have mixed views on how this should be done.

Attitude↗
PubMed2000

Absence of evidence of infection with divergent primate T-lymphotropic viruses in United States blood donors who have seroindeterminate HTLV test results.

BACKGROUND: Recent identification of divergent simian or primate T-lymphotropic viruses (STLVs; PTLVs) in bonobos (formerly called pygmy chimpanzees; Pan paniscus; viruses: STLVpan-p and STLVpp1664) and a baboon (Papio hamadryas; viruses: STLVph969 or PTLV-L) have raised the possibility of human infection with these viruses. Divergent PTLV-infected primate sera show p24 bands on HTLV-I Western blots (WBs). It was investigated whether infection by divergent PTLV-like viruses could explain a subset of United States blood donors who reacted on HTLV-I EIAs and had indeterminate HTLV-I WBs with p24 bands. STUDY DESIGN AND METHODS: Epidemiologic characteristics of 1889 donors with HTLV-I-indeterminate WBs were compared to those of donors with confirmed retrovirus infections (393 with HIV, 201 with HTLV-I, 513 with HTLV-II) and 1.6 million donors with nonreactive screening tests. To directly probe for infection with divergent PTLVs, 2 HTLV-I-indeterminate donors born in Africa and 269 representative non-African-born donors with p24 bands on HTLV-I WBs (previously shown to be negative for HTLV-I and -II DNA by PCR) were selected for PTLV PCR analysis. DNA from peripheral blood MNC samples was tested for a proviral tax sequence by PCR using generic primers that amplify HTLV-I, HTLV-II, and the divergent PTLVs. Amplified tax sequences were detected by Southern blot hybridization to a (32)P-labeled generic PTLV probe. PCR-positive samples could then be typed by hybridization with virus-specific internal probes that differentiate HTLV-I, HTLV-II, PTLV-L, and STLVpan-p. RESULTS: In the epidemiologic analysis, HTLV-indeterminate status was independently associated with age of at least 25 years (OR = 2.19; 95% CI, 1.93-2.49), black (OR = 3.27; 95% CI, 2.90-3.67) or Hispanic (OR = 1.82; 95% CI, 1.52-2.16) race or ethnicity, and donation at one blood center (Baltimore) (OR = 1. 30; 95% CI, 1.11-1.53). None of the 271 HTLV-I WB-indeterminate samples tested positive by generic PTLV PCR analysis. CONCLUSION: Although the epidemiologic data suggest the possibility of undiagnosed HTLV-I, HTLV-II, or a cross-reactive virus such as PTLV among older, black, and Hispanic blood donors, the PCR data do not support the presence of divergent PTLV infection among US blood donors with HTLV-I-indeterminate results.

Animals↗
PubMed2000

Identification with proteomics of novel proteins associated with the peribacteroid membrane of soybean root nodules.

Soybean peribacteroid membrane (PBM) proteins were isolated from nitrogen-fixing root nodules and subjected to N-terminal sequencing. Sequence data from 17 putative PBM proteins were obtained. Six of these proteins are homologous to proteins of known function. These include three chaperones (HSP60, BiP [HSP70], and PDI) and two proteases (a serine and a thiol protease), all of which are involved in some aspect of protein processing in plants. The PBM homologs of these proteins may play roles in protein translocation, folding, maturation, or degradation in symbiosomes. Two proteins are homologous to known, nodule-specific proteins from soybean, nodulin 53b and nodulin 26B. Although the function of these nodulins is unknown, nodulin 53b has independently been shown to be associated with the PBM. All of the eight proteins with identifiable homologs are likely to be peripheral rather than integral membrane proteins. Possible reasons for this apparent bias are discussed. The identification of homologs of HSP70 and HSP60 associated with the PBM is the first evidence that the molecular machinery for co- or post-translational import of cytoplasmic proteins is present in symbiosomes. This has important implications for the biogenesis of this unique, nitrogen-fixing organelle.

Amino Acid Sequence↗
PubMed2000

Prevalence of lower gastrointestinal symptoms and associated consultation behaviour in a British elderly population determined by face-to-face interview.

BACKGROUND: The incidence of organic lower gastrointestinal disease increases with age. However, the prevalence of lower gastrointestinal symptoms in a British elderly population is unclear, with previous epidemiological studies focusing on younger populations. Furthermore, there is little information about consultation behaviour associated with lower gastrointestinal symptoms. AIM: To determine the prevalence of lower gastrointestinal symptoms reported by randomly selected, elderly community subjects. METHODS: An age- and sex-stratified random sample of patients aged 65 years and over was drawn from a general practice register (n = 842). Those who had not refused to participate in an initial postal survey were invited to participate in a semi-structured physician interview at their own home to assess lower gastrointestinal symptomatology (n = 745). Non-participation bias and service use of all subjects were assessed from practice records. RESULTS: Five hundred and ninety-six (71%) patients were interviewed. Fifty-seven per cent of all participants had at least one lower gastrointestinal symptom. Individual symptoms and symptom complexes were common, affecting up to 32% of subjects. Only 24% of subjects with lower gastrointestinal symptoms consulted their general practitioner (GP) with such symptoms in the previous year. As few as 31% of subjects with new onset of the significant symptoms of rectal bleeding, abdominal pain, and a change in bowel habit consulted their GP. CONCLUSION: Lower gastrointestinal symptoms are common in a British elderly population and an important reason for GP consultation.

Abdominal Pain↗
PubMed1999

AIDS funding. The national lottery.

The government's funding of AIDS and HIV services in England is inequitable. Spending per patient in North Thames is four times that in Manchester. Deaths from AIDS in North Thames are significantly lower than in other parts of England.

Acquired Immunodeficiency Syndrome↗