Biomedical subjects

K Stevenson

Publications and source records attributed to K Stevenson.

At least 19 recordsLinked to original sources

PubMed2005

Genetic diversity of Mycobacterium avium subspecies paratuberculosis isolates from goats detected by pulsed-field gel electrophoresis.

Paratuberculosis in goats occurs worldwide causing considerable economic losses mainly due to reduced milk production. Nowadays, there is still relatively little knowledge about the epidemiology of this disease in goats, and only a few epidemiological studies have been carried out in goats naturally infected with Mycobacterium avium subspecies paratuberculosis (M. a. paratuberculosis). The objective of this study was to characterize forty four clinical caprine isolates of M. a. paratuberculosis by different molecular techniques (pulsed-field gel electrophoresis [PFGE], restriction fragment length polymorphism analysis coupled with hybridization to IS900, and IS1311 polymerase chain reaction-restriction enzyme analysis) to determine the most useful technique for molecular typing of caprine isolates, as well as to disclose the genetic variation amongst caprine isolates and the relationship with strains isolated from other animal species. PFGE was found to be the most discriminative technique identifying a total of 13 'multiplex' PFGE profiles, ten of which were novel profiles found only in caprine isolates to date. All isolates were genotyped as Type II strains, except two isolates that resembled the intermediate group referred as Type III.

Animals↗

PubMed2005

Heart failure with preserved left ventricular systolic function: a hospital cohort study.

OBJECTIVE: To investigate how patients with heart failure with preserved left ventricular systolic function (LVSF) compare with patients with reduced LVSF. DESIGN: Cohort study. SETTING: Urban university hospital. PATIENTS: 528 index emergency admissions with heart failure during the year 2000. Information on LVSF and follow up was available for 445 (84%) of these patients. RESULTS: 130 (29%) patients had preserved LVSF (defined as an ejection fraction > 40%). The median follow up was 814 days (range 632-978 days). The average (SD) age was 72 (13) years. Women accounted for 62% and 45% of patients with preserved and reduced LVSF, respectively (p = 0.001). Patients with preserved LVSF (compared with those with reduced LVSF) had a higher prevalence of left ventricular hypertrophy (56% v 29%) and aortic valve disease (mean gradient > 20 mm Hg; 31% v 9%). Fewer patients with preserved LVSF received an angiotensin converting enzyme inhibitor (65% v 78%, p = 0.008) or spironolactone (12% v 21%, p = 0.027). Anaemia tended to occur more often in patients with preserved LVSF than in those with reduced LVSF (43% v 33% for women, p = 0.12; 59% v 49% for men, p = 0.22). There was a similarly high prevalence of significant renal dysfunction in both groups (estimated glomerular filtration rate < 60 ml/min/1.73 m2 in 68% with preserved and 64% with reduced LVSF, p = 0.40). Mortality was similar in both groups (preserved versus reduced 51 (39%) v 132 (42%), p = 0.51). Compared with patients with reduced LVSF, patients with preserved LVSF tended to have a lower risk of death or hospital admission for heart failure (56 (42%) v 165 (53%), p = 0.072) but a similar rate of death or readmission for any reason. CONCLUSION: Patients with preserved LVSF had more co-morbid problems than those with reduced LVSF; however, prognosis was similar for both groups.

Aged↗

PubMed2003

Mycobacterial interspersed repetitive units (MIRU) differentiate Mycobacterium avium subspecies paratuberculosis from other species of the Mycobacterium avium complex.

Mycobacterial interspersed repetitive units (MIRU) comprise short tandem repeat structures found at multiple loci throughout the Mycobacterium tuberculosis genome and have been used for typing these pathogens. We have identified MIRU at 18 conserved loci throughout the common portions of the Mycobacterium avium subspecies paratuberculosis (MAP) and M. avium subspecies avium (MAA) genomes. Six of these loci were found to differ between MAA and MAP in the number of tandem repeat motifs occurring at each MIRU locus. Locus specific PCR at 4 of these loci segregated MAP into two major groups, which could be differentiated from ovine-pigmented strains of MAP and the MAP vaccine strain 316F. The same PCR differentiated MAA into five MIRU profiles. PCR at either MIRU locus 1 or MIRU locus 4 distinguished between MAP and all other M. avium complex (MAC) tested. PCR at both loci 1 and 4 also distinguished MAP from Mycobacterium intracellulare. MIRU typing may provide an additional simple and rapid procedure for the differentiation between MAP and other MAC.

Amino Acid Sequence↗

PubMed2003

The potential role of wild rabbits Oryctolagus cuniculus in the epidemiology of paratuberculosis in domestic ruminants.

Mycobacterium avium subspecies paratuberculosis, the organism responsible for paratuberculosis in cattle and sheep has been found in wild rabbits (Oryctolagus cuniculus) in the east of Scotland. Few studies have investigated either the level of faecal contamination by rabbits on farms, or the potential infectivity of rabbit excreta. The rate of rabbit faecal contamination deposited and the numbers encountered were estimated for 21 fields on 4 farms with a paratuberculosis problem. 7357 +/- 2571 S.E.M. rabbit faecal pellets were deposited per hectare per day and up to 81,000 pellets/ha ('standing crop') were encountered in October/November 1998. Where access to rabbits was restricted, the standing crop of faeces encountered fell to 22,000 pellets/ha. The prevalence of infection with M. a. paratuberculosis was assessed for 83 rabbits from the four farms. M. a. paratuberculosis was isolated from rabbits on all farms with an overall prevalence of 17%. Out of 17 rabbits from which urine was available, M. a. paratuberculosis was isolated from two--the first reported isolation from urine in wild rabbits. The mean number of colony-forming units per gram of infected rabbit faeces was 7.6 x 10(5) +/- 5.2 x 10(5). A relative estimate of the input of M. a. paratuberculosis onto pasture, at the stocking levels found on the four farms, showed that sheep and cattle potentially contributed 4 and 125 times more organisms/ha per day respectively than rabbits. However, rabbits could still contribute millions of M. a. paratuberculosis organisms per ha per day. Existing rabbit control measures on farms may be inadequate in reducing the risk of transmission to livestock.

Animals↗

PubMed2003

Analysis of multidrug-resistant Mycobacterium bovis from three clinical samples from Scotland.

OBJECTIVE: To determine whether multidrug-resistant (MDR) strains of Mycobacterium bovis isolated from patients in Scotland were genotypically related. DESIGN: Genotypes of MDR strains were determined using three molecular fingerprinting techniques: pulsed-field gel electrophoresis (PFGE), spoligotyping and restriction fragment length polymorphism (RFLP). PFGE profiles were also obtained for all medical and veterinary isolates occurring in Scotland in 1997-1998. RESULTS: MDR strains showed individual Dra I PFGE profiles. Case III/98 had a profile represented in both veterinary and medical populations, Case I/94 had a profile observed in medical but not veterinary isolates, and Case II/98 had a profile unique to this study. Afl II PFGE discriminated the resistant strains. Spoligotyping grouped Cases I/94 and II/98 (ST-134). Case III/98 had a spoligotype ST-140, which is commonly observed in veterinary isolates. Similarly, DRr-RFLP analysis grouped cases I/94 and II/98, whereas Case III/98 had a common veterinary profile. DRX(PGRS) RFLP gave three unique profiles. CONCLUSION: Three resistant strains were discriminated by PFGE and DRX(PGRS) RFLP, indicating that the three strains are not related in an epidemiologically relevant time scale. However, Cases I/94 and II/98 were more closely linked by spoligotyping and DRr-RFLP data. PFGE and DRr-RFLP linked Case III/98 profiles to the most common veterinary isolate.

Animals↗

PubMed2002

Meeting patient expectations of care: the major determinant of satisfaction with out-of-hours primary medical care?

BACKGROUND: Client or consumer expectation is considered to influence their satisfaction with the service provided, but its importance has not been quantified in health care. OBJECTIVE: The aim of this study was to determine the effect of "patient expectations of care" on satisfaction with care provided by out-of-hours services. METHODS: We surveyed 3457 patients who requested out-of-hours care from five practices, two general practice out-of-hours co-operatives and a deputizing service in an English health authority during late 1997. The independent variables were: the service providing the care (service type), where out-of-hours care was given (location of care) and whether the care met the patient's expectations. The independent variable was overall patient satisfaction with out-of-hours care. RESULTS: Patients who received the care they hoped for (their idealized expectation was met) were more satisfied than those who did not. Patients who attended centres were more satisfied with the care received than those who had had home visits. Patients were more satisfied if they received care from the co-operative which did not employ assistants than from the deputizing service. Idealized expectation (care which was hoped for) match, location of care and service type explained 34, 2 and 4% of the variance, respectively. Age, sex, ethnicity, access to a car, normative/comparative expectation (care which was expected) and whether patients expected and received telephone advice, a home visit or domiciliary care, and the delay between request for care and care provision were not independently associated with satisfaction. CONCLUSIONS: Meeting or failing to meet the care patients hoped for is an important predictor of patient satisfaction with out-of-hours care. Purchasers and providers of out-of-hours care should consider whether and how patient expectation of service can be managed. This may reduce patient dissatisfaction with the service they provide. These findings also have important implications for the design of studies which use patient satisfaction as an outcome variable.

Adult↗

PubMed2002

The importance of the location of fluorodeoxyglucose uptake in periprosthetic infection in painful hip prostheses.

Ten per cent of patients with hip replacement will eventually complain of significant pain after surgery, often requiring a revision arthroplasty. The majority of these patients experience aseptic loosening rather than infection. Despite significant advances made in diagnostic imaging, distinguishing infection from aseptic loosening remains a significant challenge. Imaging using fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to have excellent sensitivity in detecting infections associated with hip prostheses. However, in some studies, a high rate of false positive results has been reported, especially when increased tracer uptake adjacent to the prosthesis (which is not surrounded by bone) is used as the sole criterion for diagnosing infection. The objective of this investigation was to determine the optimal criteria for diagnosing periprosthetic infection, thereby avoiding false positive results in this setting. A total of 41 total hip arthroplasties from 32 patients and for whom complete clinical follow-up was available were included in this analysis. The location and intensity of FDG uptake were determined for each scan. Final diagnosis was made by microbiology, histopathology, surgical findings and clinical follow-up. Patients who did not undergo surgery were followed up to at least 9 months. Twelve patients were proven eventually to have periprosthetic infection. Images from 11 of these patients displayed increased tracer uptake along the interface between bone and prosthesis. The intensity of the increased tracer uptake varied from mild to moderate, with standardized uptake values less than 2. In contrast, images from uninfected, loose hip prostheses revealed very intense uptake around the head or neck of the prosthesis with standardized uptake values as high as 7. It is concluded that the intensity of increased FDG uptake is less important than the location of increased FDG uptake when FDG PET is used to diagnose periprosthetic infection in patients with hip arthroplasty. Using increased uptake as the sole criterion for diagnosing infection will result in false positive results in this setting.

Adult↗

PubMed2001

Qualitative study of pilot payment aimed at increasing general practitioners' antismoking advice to smokers.

OBJECTIVES: To elicit general practitioners' and practice nurses' accounts of changes in their clinical practice or practice organisation made to claim a pilot health promotion payment. To describe attitudes towards the piloted and previous health promotion payments. DESIGN: Qualitative, semistructured interview study. SETTING: 13 general practices in Leicester. PARTICIPANTS: 18 general practitioners and 13 practice nurses. RESULTS: Health professionals did not report substantially changing their clinical practice to claim the new payments and made only minimal changes in practice organisation. The new health promotion payment did not overcome general practitioners' resistance towards raising the issue of smoking when they felt that doing so could cause confrontation with patients. General practitioners who made the largest number of claims altered the way in which they recorded patients' smoking status rather than raising the topic of smoking more frequently with patients. PARTICIPANTS had strong negative views on the new payment, feeling it would also be viewed negatively by patients. They were, however, more positive about health promotion payments that rewarded "extra" effort-for example, setting up practice based smoking cessation clinics. CONCLUSIONS: General practitioners and practice nurses were negative about a new health promotion payment, despite agreeing to pilot it. Health promotion payments do not automatically generate effective health promotion activity, and policymakers should consider careful piloting and evaluation of future changes in health promotion payments.

Attitude of Health Personnel↗

PubMed2001

Isolation and diagnostic potential of ISMav2, a novel insertion sequence-like element from Mycobacterium avium subspecies paratuberculosis.

A novel Mycobacterium avium ssp. paratuberculosis (M. paratuberculosis) specific insertion sequence has been identified by representational difference analysis and designated as ISMav2. ISMav2 has no similarity to known mycobacterial IS elements but shows more than 50% identity to a non-composite transposon of Streptomyces coelicolor at the DNA and protein level. ISMav2 is present in at least three copies on the genome as assessed by Southern blot analysis and its potential value as a diagnostic tool was confirmed by PCR analyses on 79 M. paratuberculosis field isolates, nine M. avium ssp. avium isolates, and the reference strains of nine other mycobacterial species.

Base Sequence↗

PubMed2001

Improved preparation of high molecular weight DNA for pulsed-field gel electrophoresis from mycobacteria.

Molecular typing is now widely used to aid and supplement conventional epidemiological studies of mycobacterial diseases. Pulsed-field gel electrophoresis (PFGE), in which the entire genome can be represented as a distinct pattern of DNA restriction fragments, is a particularly powerful tool in epidemiology for the determination of clonal identity of bacteria providing information for understanding and controlling the spread of disease. Application of PFGE to the study of mycobacterial diseases has been limited because isolation of high-quality genomic DNA from mycobacterial sources has proved problematic. Here we report a simple, highly effective method for the preparation of high molecular weight DNA from a range of mycobacterial species. Cultures are continuously stirred and are homogeneous. This enables accurate quantification. The presence of detergent in buffers keeps the cells in suspension throughout preparation enabling efficient lysis. In addition, it is compatible with heat-inactivation of pathogenic mycobacteria and all of the preparation procedures can be carried out with a category III facility. This standardised method of preparation of DNA from mycobacteria means that PFGE should now be evaluated as a method for typing these organisms and it may be particularly important as a means of typing less well-characterised mycobacteria for which other techniques are not available.

Calibration↗

PubMed2001

Natural paratuberculosis infection in rabbits in Scotland.

Natural paratuberculosis infection of rabbits (Oryctolagus cuniculus) was recently diagnosed in Scotland, and an investigation into the pathology of the disease in wild rabbits is reported in this paper. Evidence of Mycobacterium avium subsp. paratuberculosis (M.a. paratuberculosis) infection was detected in 22% of 110 rabbits; the organism was cultured from 17 of 110 rabbits, and histopathological lesions consistent with M.a. paratuberculosis infection were noted in 18 of 98 rabbits examined. No macroscopical lesions suggestive of M.a. paratuberculosis infection were observed. The histopathological lesions were either severe or mild. Severe lesions consisted of extensive macrophage granulomata and numerous giant cells, with many intracellular acid-fast bacteria in the small intestine. For the examination of formalin-fixed, paraffin wax-embedded tissues, neither immunohistochemistry nor the polymerase chain reaction was as sensitive a method of diagnosis as histopathology.

Animals↗

PubMed2001

Features of primary health care teams associated with successful quality improvement of diabetes care: a qualitative study.

BACKGROUND: In quality improvement activities such as audit, some general practices succeed in improving care and some do not. With audit of care likely to be one of the major tools in clinical governance, it would be helpful to establish what features of primary health care teams are associated with successful audit in general practice. OBJECTIVE: The aim of the present study was to identify those features of primary health care teams that were associated with successful quality improvement during systematic audit of diabetes care. METHOD: Semi-structured tape-recorded interviews were carried out with lead GPs and practice nurses in 18 general practices in Leicestershire that had the opportunity to improve their care and had completed two data collections in a multipractice audit of diabetes care. The interviewees were asked to describe their practice's approach to audit and the transcripts were coded for common features and judged for strength of feeling by blinded independent raters. Features common to practices that had, and those that had not, managed to improve diabetes care were identified. RESULTS: Six features were identified reliably in the transcripts by blinded independent raters. Four were significantly associated with the successful improvement of care. Success was more likely in teams in which: the GP or nurse felt personally involved in the audit; they perceived their teamwork as good; they had recognized the need for systematic plans to address obstacles to quality improvement; and their teams had a positive attitude to continued monitoring of care. A positive attitude to audit and a personal interest in the disease were not associated with improvement in care. CONCLUSIONS: Success in improving diabetes care is associated with certain organizational features of primary health care teams. Experimental studies are required to determine whether the development of teamwork enables practice teams to identify and overcome systematically the obstacles to improved quality of patient care that face them.

Diabetes Mellitus↗

PubMed2001

Pregnancy following fertilization of zona-free, coronal cell intact human ova: Case Report.

A pregnancy by intracytoplasmic sperm injection (ICSI) of a couple whose oocytes were recovered without a zona pellucida is reported. Previous IVF/ICSI cycles indicated all oocytes had either very thin or no zona pellucida at the time of cumulus removal prior to ICSI. As a result, many ova were very fragile and lysed upon handling. In the latest attempt, six ova were recovered. After coronal cell dissection of two ova where both lacked a zona pellucida and one lysed, it was elected to attempt to inject the remaining four ova without removal of their coronal cells. The zona pellucida was not visible through the cell layer and the position of the polar body in three ova was speculative. Two embryos possessed normal pronuclei on day 1, and displayed six blastomeres prior to transfer on day 3. During preparation for transfer, sufficient coronal cells fell away to confirm both embryos lacked a zona pellucida. Pregnancy was confirmed by ultrasound observation of a fetal heart 4 weeks later. This report documents that where the zona pellucida is absent, the coronal cells provide sufficient support to maintain blastomere interaction and embryo viability and the zona pellucida is not essential for early embryo development and pregnancy.

Adult↗

PubMed2001

Endovascular management of a basilar artery false aneurysm secondary to endoscopic third ventriculostomy: case report.

OBJECTIVE AND IMPORTANCE: Third ventriculostomy for the management of noncommunicating hydrocephalus is a commonly performed procedure with a 5% complication rate. One of the known complications is basilar artery injury. CLINICAL PRESENTATION: We report a case of basilar artery injury, intraventricular hemorrhage, and false aneurysm formation in a 30-month-old boy after third ventricle floor fenestration. INTERVENTION: The false aneurysm was managed with endovascular trapping by use of Guglielmi detachable coils without morbidity. CONCLUSION: Endovascular therapy can be used successfully to manage vascular injury after third ventriculostomy.

Aneurysm, False↗

PubMed2001

Paratuberculosis infection of nonruminant wildlife in Scotland.

Recent reports of natural paratuberculosis (or Johne's disease) in rabbits, foxes, and stoats has focused debate on the presence and importance of wildlife reservoirs in the epidemiology of this disease. This paper describes an extensive study investigating 18 nonruminant wildlife species for evidence of paratuberculosis. Using both culture and histopathological analysis, fox, stoat, weasel, crow, rook, jackdaw, rat, wood mouse, hare, and badger were found to harbor Mycobacterium avium subsp. paratuberculosis, the causative organism of paratuberculosis, suggesting that the epidemiology of this disease is more complex than previously realized.

Animals↗

PubMed2001

Experimental paratuberculosis in calves following inoculation with a rabbit isolate of Mycobacterium avium subsp. paratuberculosis.

The role of wildlife species in the epidemiology of paratuberculosis has been the subject of increased research efforts following the discovery of natural paratuberculosis in free-living rabbits from farms in east Scotland. This paper describes the experimental inoculation of young calves with an isolate of Mycobacterium avium subsp. paratuberculosis recovered from a free-living rabbit. After a 6-month incubation period, all eight calves inoculated with the rabbit isolate had developed histopathological and/or microbiological evidence of M. avium subsp. paratuberculosis infection. Similar results were obtained from a group of calves infected with a bovine isolate of M. avium subsp. paratuberculosis. The virulence of the rabbit isolate for calves demonstrated in this study suggests that rabbits are capable of passing paratuberculosis to domestic ruminants and that wildlife reservoirs of M. avium subsp. paratuberculosis should therefore be considered when formulating control plans for the disease.

Animals↗

PubMed2000

Modulation of gammadelta T cells and CD1 in Mycobacterium avium subsp. paratuberculosis infection.

M.a. paratuberculosis is the causal agent of paratuberculosis (Johne's disease). Recent work has suggested that gammadelta T cells may play an important role in the early immunological response to mycobacterial diseases, and that CD1 may act as a non-classical MHC molecule in antigen presentation to these gammadelta T cells. Experimental infection of neonatal lambs with M.a. paratuberculosis was used to investigate the changes in gammadelta T cells and CD1 molecules in the gut associated lymphoid tissue 4 weeks after inoculation. Immunohistochemistry was used to label the gammadelta lymphocytes and CD1 molecules. An increase in the number of gammadelta T cells was noted in both the jejunal and ileal Peyer's patches in the gut of infected lambs, but no statistically significant change was found in the mesenteric lymph nodes. There were no obvious changes in the CD1 molecules in any tissue. This work suggests that gammadelta T cells may play a role in the initial immunological events of paratuberculosis infection.

Animals↗

PubMed2000

Thrombin induces IL-6 but not TNFalpha secretion by mouse mast cells: threshold-level thrombin receptor and very low level FcepsilonRI signaling synergistically enhance IL-6 secretion.

Mast cells become activated in multiple diseases wherein thrombin generation is often clinically apparent, but the effect of thrombin on cytokine release by mast cells remains unexplored. Thus, we examined IL-6 and TNFalpha release by thrombin-challenged mast cells. Thrombin and the protease-activated receptor (PAR)-1 peptide TRAP(14) induced these cells to secrete IL-6 in a dose-dependent fashion. Mast cells secreted > or =2800 pg IL-6/10(6) cells over 24 h, but only low levels of serotonin and no significant TNFalpha. Furthermore, at near-background levels of allergen, threshold doses of alpha-thrombin synergistically enhanced the IL-6 response (by up to 100-fold), but high-dose costimulation led to a simple additive response. Both the PI(3)- and sphingosine-kinase signaling pathways contributed importantly to the thrombin response. Our data thus clearly demonstrate that low-level thrombin and FcepsilonRI signaling can synergize to augment mast cell IL-6 responses, and that thrombin also differentially induces cytokine secretion by mast cells.

Animals↗