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Biomedical subjects

D W Thomas

Publications and source records attributed to D W Thomas.

At least 19 recordsLinked to original sources
PubMed2006

A randomised controlled trial of clinical outreach education to rationalise antibiotic prescribing for acute dental pain in the primary care setting.

OBJECTIVE: To assess the effect of educational outreach visits on antibiotic prescribing for acute dental pain in primary care. STUDY DESIGN: RCT. SETTING: General dental practices in four health authority areas in Wales. SUBJECTS AND METHODS: General dental practitioners were recruited to the study and randomly allocated to one of the three study groups (control group, guideline group or intervention group). Following the intervention, practitioners completed a standardised questionnaire for each patient that presented with acute dental pain. INTERVENTIONS: The control group received no intervention. The guideline group received educational material by post. The intervention group received educational material by post and an academic detailing visit by a trained pharmacist. The educational material included evidence-based guidelines on prescribing for acute dental pain and patient information leaflets. MAIN OUTCOME MEASURES: The number of antibiotic prescriptions issued to patients presenting with dental pain and the number of 'inappropriate' antibiotic prescriptions. Antibiotics were considered to be inappropriate if the patient did not have symptoms indicative of spreading infection. RESULTS: A total of 1,497 completed questionnaires were received from 23, 20 and 27 general dental practitioners in the control, guideline and intervention group respectively. Patients in the intervention group received significantly fewer antibiotic prescriptions than patients in the control group (OR (95% CI) 0.63 (0.41, 0.95)) and significantly fewer inappropriate antibiotic prescriptions (OR (95% CI) 0.33 (0.21, 0.54)). However, antibiotic and inappropriate antibiotic prescribing were not significantly different in the guideline group compared to the control group (OR (95% CI) 0.83 (0.55, 1.21) and OR (95% CI) 0.82 (0.53, 1.29) respectively). CONCLUSIONS: Strategies based upon educational outreach visits may be successfully employed to rationalise antibiotic prescribing by dental practitioners.

Adult↗
PubMed2006

Simultaneous pituitary-gonadal recrudescence in two Corsican populations of male blue tits with asynchronous breeding dates.

Animal populations living in geographically variable environments respond to different selection pressures. The adaptive character of the responses to environmental information determines the degree of synchrony of the breeding period with local optimal conditions. An example is provided by two populations of Mediterranean blue tits (Parus caeruleus) in Corsica, breeding in different habitats, with a 1-month difference in the onset of egg laying. This difference in the onset of lay is supposed to be adaptive because, although chicks from both populations are raised mostly on caterpillars, the timing of the appearance of caterpillars is earlier for populations of tits associated with deciduous oak trees than those associated with evergreen oak trees. Here, we show that, despite the difference in the timing of egg laying, males from these two populations start seasonal hypothalamo-hypophysial-testicular development at approximately the same time, in late winter. Specifically, the vernal recrudescence of brain GnRH-I perikarya and fibers, testes volume and song activity began around the same dates and proceeded at the same pace in late winter in both populations. Plasma testosterone and LH levels displayed seasonal variations that were shifted by less than 2 weeks compared to the 1-month difference in egg laying periods. We hypothesize that the strong selection pressures on these two populations to adapt the timing of their breeding seasons to their local environment may have acted mostly on the female egg laying dates, and not so much on the initiation and rate of seasonal recrudescence of the hypothalamo-hypophysial-testicular activity in males.

Adaptation, Physiological↗
PubMed2005

The effectiveness of out-of-hours dental services: II. patient satisfaction.

OBJECTIVE: To compare patients' satisfaction with four types of out-of-hours emergency dental service, including both 'walk-in' and telephone-access services. BASIC DESIGN: Postal questionnaire survey of patients who had attended weekend emergency dental services. Patient satisfaction measured using an adapted version of a questionnaire developed for assessing out-of-hours medical services. SETTING: Two health authorities in South Wales, UK. SUBJECTS: The 411 patients who saw a dentist and completed the patient satisfaction questionnaire. RESULTS: The quality of the dentist-patient encounter was similar across services, with most patients being satisfied with the dentist's attitude and manner, the explanations and advice given, and having to see an unfamiliar dentist. Satisfaction was lower, and differed more across services in relation to service accessibility and delays in getting to see a dentist out-of-hours. The walk-in services were perceived as the least accessible: around 40% said they had problems contacting a dentist when the surgery was closed (compared with 16% and 29% in the other two, telephone-access services). Only 12-14% of telephone-access patients said they would be 'happy with advice plus a reliable appointment when surgeries re-opened', whereas almost half of walk-in patients thought this. CONCLUSIONS: Despite overall satisfaction with the dentist-patient encounter, there was relative dissatisfaction with the accessibility of all services, especially the walk-in services. Out-of-hours dental services should be better designed to reflect patients' needs: the need for telephone advice as well as face-to-face consultations, and greater awareness that theoretically available services may be difficult to access unless public expectations and awareness are raised.

After-Hours Care↗
PubMed2005

The effectiveness of out-of-hours dental services: I. Pain relief and oral health outcome.

OBJECTIVE: To compare the effectiveness of four types of out-of-hours emergency dental service, including both 'walk-in' and telephone-access services. BASIC DESIGN: Questionnaire survey of patients attending weekend emergency dental services, with measurement of self-reported oral health status and dental pain (at attendance and follow-up) and retrospective judgements of change in oral health status. SETTING: Two health authorities in South Wales, UK. SUBJECTS: A total of 783 patients who completed questionnaires at attendance, and 423 who completed follow-up questionnaires. RESULTS: For patients who saw a dentist there were no consistent differences in the effectiveness of the four services, whether measured as pain relief, oral health gain or using patients' retrospective transition judgements about feeling better after their episode of emergency dental care. The proportion of patients reporting no improvement (transition judgements), either an hour after or the day after seeing the dentist, was surprisingly high (30-40% and 23-38% respectively). Although the 'rotas for all' - a telephone-access GDP-provided service for both registered and unregistered patients - achieved both the highest reductions in pain scores and the greatest improvements in dental health status between attendance and follow-up, this effect may reflect health gains due to care received after the episode of emergency dental care. CONCLUSIONS: Neither the setting where emergency dental patients are seen, nor the type of dentist who sees them, appear to have any significant effect on patient-reported health outcomes. Although further exploration of the factors that predict poor pain relief or low oral health gain is required, future research on these services should focus on the process of care and accessibility.

Adolescent↗
PubMed2005

A review of the microbiology, antibiotic usage and resistance in chronic skin wounds.

Chronic leg and foot wounds represent an increasing burden to healthcare systems as the age of the population increases. The deep dermal tissues of all chronic wounds harbour microorganisms, however, the precise interaction between microbes in the wounds and impaired healing is unknown. With regard to antibiotic therapy, there is a lack of evidence concerning its effectiveness, optimal regimens or clinical indications for treatment. Despite this lack of evidence, antibiotics are frequently a feature of the management of chronic wounds and these patients receive significantly more antibiotic prescriptions (both systemic and topical) than age and sex-matched patients. Current guidelines for antibiotic prescribing for such wounds are often based on expert opinion rather than scientific fact and may present difficulties in interpretation and implementation to the clinician. Although the increasing prevalence of antibiotic resistance is widely recognized, the relationships between antibiotic resistance, chronic wound microbiology and rationales for antibiotic therapy have yet to be determined. This review discusses the role of microbes in chronic wounds from a clinical perspective with particular focus on the occurrence of bacteria and their impact on such wounds. The evidence and role of antibiotics in the treatment of such wounds are outlined and current practice of antibiotic usage for chronic wounds in the primary care setting described. The implications of antibiotic usage with regard to antibiotic resistance are also considered.

Animals↗
PubMed2005

Langerhans cell histiocytosis in sequential discordant lymphoma.

B cell non-Hodgkin lymphoma of the follicular subtype (grade 3/3) affecting the nasopharynx and breast, and containing foci of Langerhans cell histiocytosis, was diagnosed in a 56 year old white woman who was a longstanding heavy smoker. Four years before this she had developed stage 1a mixed cellularity Hodgkin lymphoma affecting the right inguinal region, which was treated by irradiation and chemotherapy without recurrence. Review of the original Hodgkin lymphoma histology demonstrated a small focus of Langerhans cell histiocytosis. This is thought to be the first recorded case of Langerhans cell histiocytosis occurring in a sequential discordant lymphoma. Its importance is discussed.

Breast Neoplasms↗
PubMed2005

Candida albicans peritonitis in a patient with Felty's syndrome.

A 53 year old man with Felty's syndrome presented with abdominal pain and fever. He underwent a laparotomy after starting broad spectrum antibiotics. An intestinal biopsy showed skip ulcers with fungal hyphae. Peritoneal exudates grew Candida albicans. He was started on intravenous fluconazole and then switched to liposomal amphotericin to which he showed a good clinical response. After one month at home he was readmitted with candidosis and died of a myocardial infarction.

Candidiasis↗
PubMed2005

Ectopic submandibular gland presenting as a swelling in the floor of mouth.

The authors describe a patient who presented with a left sublingual swelling. Ultrasonic and sialographic investigation showed no salivary tissue in the expected left submandibular region, but a large salivary gland in the left floor of the mouth deep to the mylohyoid muscle. This is likely to represent an ectopically positioned submandibular gland.

Adult↗
PubMed2004

Extracellular matrix metabolites as potential biomarkers of disease activity in wound fluid: lessons learned from other inflammatory diseases?

The new era of pharmacogenetics has identified a potential for individuals to receive customized treatments for a variety of disease states. For such individualized treatments to fulfil their potential, it will be essential for clinicians to be able to monitor disease activity, ideally in a rapid, noninvasive fashion. The accessibility of the skin offers much potential to develop noninvasive tests of metabolic and disease activity for clinical use. Impaired human wound healing in the skin is a chronic inflammatory disorder in which the development of such tests has considerable potential, aiding clinical decision making and monitoring responses to treatment. This review article discusses how studies in other human diseases have highlighted potential biochemical markers (biomarkers) of disease activity in secreted biofluids, as aids to determining disease and metabolic activity within tissues. Using, as examples, lessons learned in the study of disease activity and prognosis of other chronic inflammatory conditions, such as osteoarthritis and periodontal disease, this review highlights the potential of dermal extracellular matrix (ECM) components (collagens, proteoglycans, hyaluronan and glycoproteins) for such uses. The limitations of currently utilized techniques and the concept that analysis of ECM components in wound fluid may represent useful biomarkers of disease activity are also discussed.

Biomarkers↗
PubMed2003

Anaerobic cocci populating the deep tissues of chronic wounds impair cellular wound healing responses in vitro.

BACKGROUND: Anaerobic cocci are estimated to be present in the deep tissues of over 50% of chronic skin wounds. While the part they play in the chronicity of these wounds is uninvestigated, anaerobic cocci have previously been shown to be involved in other chronic inflammatory human conditions. METHODS: In this study the anaerobic microflora of the deep tissues of 18 patients with refractory chronic venous leg ulcers (mean age 80.3 years; mean duration > 24 months) was characterized using strict anaerobic culture conditions. The effect of the anaerobic organisms isolated from these tissues on extracellular matrix (ECM) proteolysis and cellular wound healing responses was studied using in vitro models. RESULTS: Anaerobic organisms were present in the deep tissues of 14 of 18 wounds and were principally Peptostreptococcus spp. The effects of three Peptostreptococcus spp. isolated from these wounds (P. magnus, P. vaginalis and P. asaccharolyticus) on cellular wound healing responses were compared with those of two pathogenic organisms also isolated from these wounds (Pseudomonas aeruginosa and Citrobacter diversus). While the direct ECM proteolytic activity exhibited by the Peptostreptococcus spp. was limited, they did significantly inhibit both fibroblast and keratinocyte proliferation, but only at high concentrations. However, at lower concentrations peptostreptococcal supernatants profoundly inhibited keratinocyte wound repopulation and endothelial tubule formation. The magnitude of these effects varied between strains and they were distinct from those demonstrated by Pseudomonas aeruginosa and Citrobacter diversus. CONCLUSIONS: These studies confirm the importance of anaerobic organisms in chronic wounds and demonstrate an indirect, strain-specific mechanism by which these microorganisms may play a part in mediating the chronicity of these wounds.

Aged↗
PubMed2003

Molecular analysis of the microflora in chronic venous leg ulceration.

There is growing evidence to suggest that the resident microflora of chronic venous leg ulcers impairs cellular wound-healing responses, thereby playing an important role in maintaining the non-healing phenotype of many of these wounds. The significance of individual species of bacteria will remain unclear until it is possible to characterize fully the microflora of such lesions. The limitations and biases of culture-based microbiology are being realized and the subsequent application of molecular methods is revealing greater diversity within mixed bacterial populations than that demonstrated by culture alone. To date, this approach has been limited to a small number of systems, including the oral microflora. Here, for the first time, the comprehensive characterization of the microflora present in the tissue of a chronic venous leg ulcer is described by the comparison of 16S rDNA sequences amplified directly from the wound tissue with sequences obtained from bacteria that were isolated by culture. The molecular approach demonstrated significantly greater bacterial diversity than that revealed by culture. Furthermore, sequences were retrieved that may possibly represent novel species of bacteria. It is only by the comprehensive analysis of the wound microflora by both molecular and cultural methods that it will be possible to further our understanding of the role of bacteria in this important condition.

Acinetobacter↗
PubMed2003

'Toothache stories': a qualitative investigation of why and how people seek emergency dental care.

OBJECTIVE: To understand from the patient's perspective the types of dental problem which present at weekends, how they affect people, and the care-seeking behaviour of emergency dental patients. BASIC DESIGN: Consecutive patients attending two emergency dental clinics at weekends were interviewed prior to seeing the dentist. The audio-recorded interview transcripts were analysed using the "framework" method of applied qualitative data analysis. SETTING: A community-based and a dental hospital emergency dental clinic. SUBJECTS: 44 emergency dental patients. RESULTS: Pain was the main presenting symptom, a key domain of quality of life and the underlying cause of most other quality of life effects. However, for patients deciding what symptoms mean--crucially whether they mean they need to see a dentist urgently--a wide range of other contextual factors come into play. These go beyond the individual patient's recent and current perception of symptom intensity. They encompass past experience of similar symptoms, past care-seeking experiences, anticipated effects on quality of life, anticipated service availability, joint decision-making and lay information from family and friends, professional opinions from non-dentists, expectations concerning what work dentists should do, and what symptoms distinguish "simple toothache" from more serious problems. CONCLUSIONS: The effects of, and meanings which people attach to, acute dental symptoms are complex. Combined with poor awareness of the existence of emergency dental services it is not surprising that patients' pathways to care are correspondingly complicated. The planning of emergency dental services should be based on a broader, patient-derived understanding of the need for them.

Adolescent↗
PubMed2002

Wound healing.

Explore the source record for details and available documents.

Connective Tissue Growth Factor↗
PubMed2002

Heterogeneity within the gram-positive anaerobic cocci demonstrated by analysis of 16S-23S intergenic ribosomal RNA polymorphisms.

Peptostreptococci are gram-positive, strictly anaerobic bacteria which, although regarded as members of the commensal human microflora, are also frequently isolated from sites of clinical infection. The study of this diverse group of opportunist pathogens has been hindered by an inadequate taxonomy and the lack of a valid identification scheme. Recent re-classification of the Peptostreptococcus family into five distinct genus groups has helped to clarify the situation. However, this has been on the basis of 16S rRNA sequence determinations, which are both time-consuming and expensive. The aim of the present study was to evaluate the use of PCR-amplified ribosomal DNA spacer polymorphisms for the rapid differentiation of the currently recognised taxa within the group of anaerobic gram-positive cocci. A collection comprising 19 reference strains with representatives of each of the 15 species, two close relatives and two of the well-characterised groups, together with 38 test strains was studied. All strains were identified to species group level by phenotypic means. Amplification of the 16S-23S intergenic spacer region (ISR) with universal primers produced distinct banding patterns for all the 19 reference strains and the patterns could be differentiated easily visually. However, of the 38 test strains, less than half could be speciated from ISR analysis alone. Only five groups produced correlating banding patterns for all members tested (Peptoniphilus lacrimalis, P. ivorii, Anaerococcus octavius, Peptostreptococcus anaerobius and Micromonas micros). For other species, either the type strain differed significantly from other species members (e.g., A. hydrogenalis) or there appeared to be considerable intra-species variation (e.g., A. vaginalis). Partial 16S rRNA gene sequences for the 'trisimilis' and 'betaGAL' groups showed that both are most closely related to the Anaerococcus group. This work highlights the heterogeneous nature of a number of Peptostreptococcus species and hence the need for still further revision of the taxonomy of this important group of pathogens.

Anaerobiosis↗
PubMed2002

Design of a multiblock phantom for radiotherapy dosimetry applications.

This note describes the design of a multiblock semi-anatomic phantom, which lends itself to a variety of radiotherapy dosimetry applications, in particular, the audit of external beam treatment planning and delivery. The basic building blocks of the phantom were formed from a variety of tissue substitute materials and could be assembled in many ways to model different cross-sections through the body.

Equipment Design↗
PubMed2001

Energetic and fitness costs of mismatching resource supply and demand in seasonally breeding birds.

By advancing spring leaf flush and ensuing food availability, climatic warming results in a mismatch between the timing of peak food supply and nestling demand, shifting the optimal time for reproduction in birds. Two populations of blue tits (Parus caeruleus) that breed at different dates in similar, but spatially distinct, habitat types in Corsica and southern France provide a unique opportunity to quantify the energetic and fitness consequences when breeding is mismatched with local productivity. As food supply and demand become progressively mismatched, the increased cost of rearing young pushes the metabolic effort of adults beyond their apparent sustainable limit, drastically reducing the persistence of adults in the breeding population. We provide evidence that the economics of parental foraging and limits to sustainable metabolic effort are key selective forces underlying synchronized seasonal breeding and long-term shifts in breeding date in response to climatic change.

Adaptation, Physiological↗