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R Thomson

Publications and source records attributed to R Thomson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Ages of mutations on a coalescent tree.

Using the coalescent process, DNA sequences of a sample of individuals can be used to study the phylogenetic history of the individuals. Under the infinitely-many-sites mutation model, the DNA sequence data can be summarized by the number of segregating sites (which is numerically equivalent to the number of mutations on the tree). A number of methods exist, including a recursive method presented in this paper, that obtain an estimate of the age of the most recent common ancestor (MRCA), given the number of mutations. This paper introduces a method for finding the ages of mutations, given the total number of mutations on the tree. While the result is not useful in estimating the age of a specific segregating site, it is useful in examining the underlying assumption of a relatively constant population over time. This utilization of the result is illustrated using DNA sequence data obtained from a sample of Amerindians of the Nuu-Chah-Nulth tribe.

Base Sequence↗
PubMed1998

Decision support and disease management: a logic engineering approach.

This paper describes the development and application of PROforma, a unified technology for clinical decision support and disease management. Work leading to the implementation of PROforma has been carried out in a series of projects funded by European agencies over the past 13 years. The work has been based on logic engineering, a distinct design and development methodology that combines concepts from knowledge engineering, logic programming, and software engineering. Several of the projects have used the approach to demonstrate a wide range of applications in primary and specialist care and clinical research. Concurrent academic research projects have provided a sound theoretical basis for the safety-critical elements of the methodology. The principal technical results of the work are the PROforma logic language for defining clinical processes and an associated suite of software tools for delivering applications, such as decision support and disease management procedures. The language supports four standard objects (decisions, plans, actions, and enquiries), each of which has an intuitive meaning with well-understood logical semantics. The development toolset includes a powerful visual programming environment for composing applications from these standard components, for verifying consistency and completeness of the resulting specification and for delivering stand-alone or embeddable applications. Tools and applications that have resulted from the work are described and illustrated, with examples from specialist cancer care and primary care. The results of a number of evaluation activities are included to illustrate the utility of the technology.

Decision Support Systems, Clinical↗
PubMed1998

A community survey of patients with atrial fibrillation: associated disabilities and treatment preferences.

BACKGROUND: Anticoagulants are effective in preventing stroke in those with atrial fibrillation, but most patients remain untreated. AIM: To investigate the prevalence of disability, cognitive impairment, and problems with compliance in a representative sample of the elderly with atrial fibrillation, and to determine whether they would want treatment and how they would like services to be arranged. METHOD: In a survey of a random sample of 4843 elderly subjects, those with atrial fibrillation were identified using electrocardiograms. Views on treatment were obtained using a structured interview. Disability was assessed using the Office of Population Censuses and Surveys Disability Scale and cognitive status using the Mini Mental State Examination. General practitioners were asked, via questionnaire, for their views on each subject's compliance. RESULTS: Two hundred and seven elderly people with atrial fibrillation were identified. Almost all subjects expressed a willingness to undertake treatment to prevent stroke and preferred blood testing performed outside of hospital. Disability (82.7%), cognitive impairment (25.7%), and problems with compliance (25.0%) were common, but the prevalence of these difficulties was not substantially different from the general elderly population, and in many cases they could be overcome (e.g. only 10% of subjects had problems with compliance and no-one who could help them to comply). CONCLUSIONS: Most elderly people with atrial fibrillation would accept treatment to prevent stroke. Disability, cognitive impairment, and problems with compliance may make it difficult to treat this patient group. An increase in the use of anticoagulants should be accompanied by the development of services appropriate to this frail population.

Aged↗
PubMed1997

Drug misuse services. No quick fixes.

The Department of Health's new funding formula for drug misuse services will reduce funding in districts with the highest demand for services. Some regions will receive up to four times more per reported episode of drug misuse than others. This is due, in part, to the inclusion of numbers in rented accommodation in the funding formula.

Financing, Government↗
PubMed1997

Assessment of bog-body tissue preservation by pyrolysis-gas chromatography/mass spectrometry.

Flash pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) was used to assess the quality and mechanism of protein preservation in the tissue of Iron Age bog bodies from Lindow, UK, and south-eastern Drenthe, The Netherlands. Abundant pyrolysis products of the fresh skin tissue, including 2,5-diketopiperazines of Pro-Gly, Pro-Ala, Pro-Val, Pro-Pro and Hyp, were readily assigned to specific amino acid or dipeptide moieties. Comparison of the pyrolysates of the bog-body tissues with that of modern samples revealed qualitative similarities suggesting good preservation of the collagen and non-collagenous proteins in the ancient tissues. Examination of the pyrolysates of samples of fresh calf skin, which had been treated with various vegetable tanning agents, clearly revealed markers of non-hydrolysable tannins including 1,2-benzenediol, 1,3-benzenediol and 1,2,3-benzenetriol, although chromatographic quality inevitably diminished with increasing functionalization of the compounds. Such markers were not detected in the pyrolysates of the bog-body tissues. Instead 4-isopropenylphenol, a characteristic pyrolysis product of Sphagnum moss, was detected in both solvent-extracted and base-treated samples of tissue. The presence of 4-isopropenylphenol in the pyrolysates of the bog-body tissues provides evidence that their preservation involves reactions of amino acids with sphagnum acid, and possibly other agents derived from the peat. The study constitutes the first chemical characterization of the pyrolysis products of modern and ancient collagen.

Aged↗
PubMed1997

PROforma: a general technology for clinical decision support systems.

The need for flexible and well understood knowledge representations which are capable of capturing clinical guidelines and protocols for decision support systems is widely recognised. The PROforma method for specifying clinical guidelines and protocols comprises a graphical notation for their design, and a formal knowledge representation language to enable them to be executed by a computer to support the management of medical procedures and clinical decision making. PROforma technology consists of a graphical knowledge editor for the creation of guidelines, and an enactment engine for testing and executing them. This paper provides an overview of the motivation and structure of PROforma, and illustrates its use in the development of clinical applications.

Adult↗
PubMed1997

HTLV-associated myelopathy in a cohort of HTLV-I and HTLV-II-infected blood donors. The REDS investigators.

OBJECTIVE: HTLV-I-associated myelopathy (HAM) is a slowly progressive spastic paraparesis caused by infection with human T-lymphotropic virus type I (HTLV-I). The prevalence of HAM among those infected with HTLV-I is poorly defined, and the association of a similar myelopathy with HTLV-II infection has not been confirmed. DESIGN: Cross-sectional examination of HTLV-I, HTLV-II, and control subjects from the baseline visit of a cohort study. SETTING/ SUBJECTS: Persons testing HTLV seropositive at the time of blood donation at five U.S. blood centers, their seropositive sex partners, and a matched control group of HTLV seronegative blood donors. MEASUREMENTS: HTLV-I and HTLV-II were differentiated by serology and/or polymerase chain reaction. All subjects received systematic neurologic screening examinations. RESULTS: A diagnosis of myelopathy was confirmed in four of 166 HTLV-I subjects (2.4%, 95% confidence interval 0.7%, 6.1%) and in one of 404 HTLV-II subjects (0.25%, 95% confidence interval 0.0%, 0.6%). None of the 798 controls had a similar myelopathy, although one had longstanding typical multiple sclerosis. CONCLUSIONS: Our data also suggest that HAM occurs more frequently among HTLV-I-infected subjects than reported by previous studies. The HTLV-II infected myelopathy patient identified in this cohort, together with three other case reports in the literature, implies a pathogenic role for this human retrovirus. The diagnosis of HTLV-associated myelopathy should be considered in cases of spastic paraparesis or neurogenic bladder when risk factors for HTLV-I or HTLV-II infection are present.

AIDS Serodiagnosis↗
PubMed1996

Male-to-female transmission of human T-cell lymphotropic virus types I and II: association with viral load. The Retrovirus Epidemiology Donor Study Group.

SUMMARY: Risk factors for male-to-female sexual transmission of human T-lymphotropic virus types I and II (HTLV-I/II) were investigated among HTLV-seropositive volunteer blood donors and their long-term (> or = 6 month) sex partners. Direction of transmission in concordantly seropositive pairs was assessed by analyzing risk factors for HTLV infection. Donors and their partners were also questioned regarding sexual behaviors during their relationships; HTLV antibody titers and viral load were determined for specimens from male partners. Among 31 couples in whom HTLV-infected men likely transmitted infection to their partners (11 HTLV-I and 20 HTLV-II) and 25 male-positive, female-negative couples (8 HTLV-I and 17 HTLV-II), HTLV transmitter men had been in their relationships longer (mean 225 months vs. 122 months) and had higher viral loads (geometric mean 257,549 vs. 2,945 copies/300,000 cells for HTLV-I; 5,541 vs. 118 copies/300,000 cells for HTLV-II) than non-transmitters (P = 0.018 and P = 0.001 for duration of relationship and viral load, respectively, logistic regression analysis). Transmitter men also tended to have higher antibody titers against various env and whole virus proteins than non-transmitters. The identification of high viral load and duration of relationship as risk factors provides a biologically plausible framework in which to assess risk of sexual transmission of the HTLVs.

Adult↗
PubMed1996

Clinical audit and the purchaser-provider interaction: different attitudes and expectations in the United Kingdom.

OBJECTIVES: To explore and describe the views on clinical audit of healthcare purchasers and providers, and in particular the interaction between them, and hence to help the future development of an appropriate interaction between purchasers and providers. DESIGN: Semistructured interviews. SETTING: Four purchaser and provider pairings in the former Northern Region of the National Health Service (NHS) in England. SUBJECTS: Chief executives, contracts managers, quality and audit leaders, directors of public health, consultants, general practitioners, audit support staff, and practice managers (total 42). MAIN MEASURES: Attitudes on the present state and future development of clinical audit. RESULTS: Purchasers and providers shared common views on the purpose of clinical audit, but there were important differences in their views on the level and appropriateness of involvement of health care purchasers, integration with present NHS structures and processes (including contracting and the internal market), priority setting for clinical audit, the effects of clinical audit on service development and purchasing, change in behaviour, and the sharing of information on the outcomes of clinical audit. CONCLUSIONS: There are important differences in attitudes towards, and expectations of, clinical audit between health care purchasers and providers, at least in part due to the limited contact between them on audit to date. The nature of the relation and dialogue between purchasers and providers will be critical in determining whether clinical audit meets the differing aspirations of both groups, while achieving the ultimate goal of improving the quality of patient care.

Administrative Personnel↗