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Biomedical subjects

S Riley

Publications and source records attributed to S Riley.

At least 19 recordsLinked to original sources
PubMed2006

Seroprevalence of IgG antibodies to SARS-coronavirus in asymptomatic or subclinical population groups.

We systematically reviewed the current understanding of human population immunity against SARS-CoV in different groups, settings and geography. Our meta-analysis, which included all identified studies except those on wild animal handlers, yielded an overall seroprevalence of 0.10% [95% confidence interval (CI) 0.02-0.18]. Health-care workers and others who had close contact with SARS patients had a slightly higher degree of seroconversion (0.23%, 95% CI 0.02-0.45) compared to healthy blood donors, others from the general community or non-SARS patients recruited from the health-care setting (0.16%, 95% CI 0-0.37). When analysed by the two broad classes of testing procedures, it is clear that serial confirmatory test protocols resulted in a much lower estimate (0.050%, 95% CI 0-0.15) than single test protocols (0.20%, 95% CI 0.06-0.34). Potential epidemiological and laboratory pitfalls are also discussed as they may give rise to false or inconsistent results in measuring the seroprevalence of IgG antibodies to SARS-CoV.

Antibody Formation↗
PubMed2006

Butyrate modulates TGF-beta1 generation and function: potential renal benefit for Acacia(sen) SUPERGUM (gum arabic)?

Anecdotal evidence suggests that high fibre supplementation of dietary intake may have health benefits in renal disease related to alterations in circulating levels of short-chain fatty acids. The aim of the study was to examine the hypothesis that dietary manipulation may increase serum butyrate and thus have potential beneficial effects in renal disease. We examined the effect of dietary supplementation with a gum arabic sample of standardized molecular characteristics, Acacia(sen) SUPERGUM EM2 (SUPERGUM), on systemic levels of butyrate in normal human subjects. In an in vitro study, we also examined the potential role of butyrate in modifying the generation of the profibrotic cytokine transforming growth factor-beta (TGF-beta1) by renal epithelial cells. Following 8 weeks of dietary supplementation with 25 g/day of SUPERGUM, there was a two-fold increase in serum butyrate (n=7, P=0.03). In vitro work demonstrated that exposure of renal epithelial cells to elevated concentrations of butyrate suppressed both basal and stimulated TGF-beta1 synthesis. The action of butyrate was mediated by suppression of the extracellular signal-regulated kinase/mitogen-activated protein kinase signalling pathway. In addition, butyrate exposures reduced the response of renal epithelial cells to TGF-beta1 as assessed by luciferase activity of a TGF-beta-responsive reporter construct. Attenuation of TGF-beta1 signalling was associated with reduced phosphorylation of Smad 3 and decreased trafficking of TGF-beta1 receptors into signalling, non-lipid raft-associated membrane fractions. In conclusion, the data demonstrate that dietary supplementation with SUPERGU increased serum butyrate, which at least in vitro has beneficial effects on renal pro-fibrotic cytokine generation.

Butyrates↗
PubMed2005

Radiosurgery planning supported by the GEMSS grid.

GEMSS (Grid Enabled Medical Simulation Services IST-2001-37153) is an EU project funded to provide a test bed for Grid-enabled health applications. Its purpose is evaluation of Grid computing in the health sector. The health context imposes particular constraints on Grid infrastructure design, and it is this that has driven the feature set of the middleware. In addition to security, the time critical nature of health applications is accommodated by a Quality of Service component, and support for a well defined business model is also included. This paper documents experience of a GEMSS compliant radiosurgery application running within the Medical Physics department at the Royal Hallamshire Hospital in the UK. An outline of the Grid-enabled RAPT radiosurgery application is presented and preliminary experience of its use in the hospital environment is reported. The performance of the software is compared against GammaPlan (an industry standard) and advantages/disadvantages are highlighted. The RAPT software relies on features of the GEMSS middleware that are integral to the success of this application, and together they provide a glimpse of an enabling technology that can impact upon patient management in the 21st century.

Decision Support Systems, Clinical↗
PubMed2004

Strategic options for sustainable water management at new developments: the application of a simulation model to explore potential water savings.

Research on appropriate technologies and infrastructures to support water reuse has progressed rapidly over recent decades and there are now a wide range of source--treatment--reuse options for planners to choose from. Although the economics of water reuse schemes favours application to new developments rather than retrofit projects, there are few studies which have sought to address strategic option selection issues for large developments. The potential advantages of using treatment and reuse systems in new developments require an understanding of the relationships between a wide variety of social, environmental, technological, and operational factors. The operational effectiveness and economic efficiency of specific technology choices will vary as a function of network configuration, wastewater characteristics, how different technologies respond to dynamic loading (variability of feed strength and flow) and potential spiking, as well as equipment reliability, climate and household behaviour. Using a commercially available software package, the study reports the design and implementation of a low resolution simulation tool to explore sustainable water management options for a live case study site in the south of England (a peri-urban development of 4,500 new homes) with particular reference to opportunities for rainwater harvesting, and water reuse.

Climate↗
PubMed2003

Differentiated chondrocytes for cartilage tissue engineering.

Trauma to the articular cartilage surface of the joint represents a challenging clinical problem due to the very limited ability of this tissue to self-repair. Moreover, repair techniques such as microfracture, which introduce cells into the joint, have unpredictable clinical outcomes as they produce a fibrocartilage tissue that degenerates with time. Alternative treatments include tissue reconstruction with autograft and allograft tissue. However, these procedures are restricted by the availability of suitable donor tissue. These limitations have been the driving force behind the emerging field of articular cartilage tissue engineering. This paper will highlight and contrast the key challenges associated with the tissue engineering of this neo-tissue using differentiated adult cells. The various components of the tissue engineering process will be described including the choice of donor cell/tissue type and the selection of scaffolds that guide the formation of tissue. The ability of the tissue engineered implants to stimulate the repair of defects in vivo will also be discussed. Tissue engineering approaches may, in the future, provide an ideal alternative to the current surgical treatments for cartilage repair.

Adult↗
PubMed2001

Mirror, mirror on the wall, who is the ugliest of them all? The psychopathology of mirror gazing in body dysmorphic disorder.

UNLABELLED: Patients with Body Dysmorphic Disorder (BDD) may spend many hours in front of a mirror but little is known about the psychopathology or the factors that maintain the behaviour. A self-report mirror gazing questionnaire was used to elicit beliefs and behaviours in front of a mirror. Two groups were compared, which consisted of 55 controls and 52 BDD patients. RESULTS: Prior to gazing, BDD patients are driven by the hope that they will look different; the desire to know exactly how they look; a belief that they will feel worse if they resist gazing and the desire to camouflage themselves. They were more likely to focus their attention on an internal impression or feeling (rather than their external reflection in the mirror) and on specific parts of their appearance. They were also more likely to practise showing the best face to pull in public or to use "mental cosmetic surgery" to change their body image than controls. BDD patients invariably felt worse after mirror gazing and were more likely to use ambiguous surfaces such as the backs of CDs or cutlery for a reflection. CONCLUSION: Mirror gazing in BDD consists of a series of complex safety behaviours. It does not follow a simple model of anxiety reduction that occurs in the compulsive checking of obsessive-compulsive disorder. The implications for treatment are discussed.

Adult↗
PubMed2001

Association of prolonged hyperglycemia with glomerular hypertrophy and renal basement membrane thickening in the Goto Kakizaki model of non-insulin-dependent diabetes mellitus.

The aim of the current study was to characterize the effects of prolonged hyperglycemia on renal structure and function using a model of non-insulin-dependent diabetes mellitus: the Goto Kakizaki (GK) rat, which does not have confounding variables, such as hyperlipidemia, obesity, or elevated blood pressure. The data show that hyperglycemia in this model was not associated with the development of significant proteinuria, but it was associated with the development of definitive age-dependent renal structural changes. These changes consisted of thickening of glomerular basement membrane at 35 weeks and tubular basement membrane. This thickening was accompanied by marked glomerular hypertrophy resulting from a parallel increase in total capillary luminal volume and mesangial volume, but fractional capillary and mesangial volumes remained unchanged. There was evidence of podocyte injury, as assessed by de novo expression of desmin. In contrast, there was no evidence of mesangial cell activation, as assessed by their de novo expression of alpha-SMA. Interstitial monocyte/macrophage influx increased significantly in GK rats at 12 weeks compared with Wistar controls. Glomerular macrophage infiltration was elevated significantly in 35-week GK rats. The structural changes described in the GK rat are similar to those described in prolonged non-insulin-dependent diabetes mellitus patients who have not developed overt renal disease. This model allows us to investigate further the mechanisms involved in the pathogenesis of the consequences of prolonged hyperglycemia.

Aging↗
PubMed2000

Photoencapsulation of chondrocytes in poly(ethylene oxide)-based semi-interpenetrating networks.

A photopolymerizing hydrogel system provides an efficient method to encapsulate cells. The present work describes the in vitro analysis of bovine and ovine chondrocytes encapsulated in a poly(ethylene oxide)-dimethacrylate and poly(ethylene glycol) semi-interpenetrating network using a photopolymerization process. One day after encapsulation, (3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenyl-2H-tetrazolium bromide) (MTT) and light microscopy showed chondrocyte survival and a dispersed cell population composed of ovoid and elongated cells. Biochemical analysis demonstrated proteoglycan and collagen contents that increased over 2 weeks of static incubation. Cell content of the gels initially decreased and stabilized. Biomechanical analysis demonstrated the presence of a functional extracellular matrix with equilibrium moduli, dynamic stiffness, and streaming potentials that increased with time. These findings suggest the feasibility of photoencapsulation for tissue engineering and drug delivery purposes.

Animals↗
PubMed2000

Mortality and morbidity after hip fracture: can evidence based clinical pathways make a difference?

OBJECTIVE: To evaluate whether evidence based clinical pathways for acute management of hip fracture have an effect on patient care, short term mortality, or residential status. METHODS: Observational cohort study comparing management, as determined by medical record review, and outcomes, as determined by telephone followup 4 months post-fracture, before (n = 455) and after (n = 481) clinical pathway implementation within pathway hospitals as well as between patients admitted to hospitals with (n = 2) and without (n = 4) pathways. RESULTS: Mean age was 82 years, 80% were women and 30% were admitted from nursing homes. Significant improvement in best practice as recommended by evidence based clinical guidelines was evident in pathway hospitals for most components of care. However, compliance was variable and nonpathway hospitals performed better for some (use of spinal anesthesia, avoidance of urinary catheters). After adjusting for potential confounders, no difference was found in 4 month mortality between the pathway (17.6%) and non-pathway (16.8%) patients (OR 0.8, 95% CI 0.5-1.5). There was a nonsignificant reduction in median acute care hospital length of stay of 1 day (p = 0.200) for non-nursing home patients and a significant reduction of 1 day (p = 0.038) for nursing home patients in the pathway hospitals. There was a nonsignificant decrease in admission rates for new patients to nursing homes in pathway hospitals (18.5%) compared to non-pathway hospitals (24.3%) (OR 0.5, 95% CI 0.3-1.1). CONCLUSION: Clinical pathways were associated with increased use of evidence based best practice, some reduction in acute hospital length of stay, but no significant effect on 4 month mortality or residential status. Their development and maintenance were resource intensive and further work on the implementation of evidence based guidelines is needed to determine whether they can influence patient outcomes.

Aged↗
PubMed1999

Endocarditis caused by group A beta-hemolytic Streptococcus in an infant: case report and review.

Acute bacterial endocarditis in the absence of underlying heart disease is rare. We report the occurrence of endocarditis caused by group A beta-hemolytic Streptococcus (GABHS), following varicella, in a 5-month-old child without heart disease. In addition to this child, seven other children with endocarditis caused by GABHS have been reported since 1966, six of whom did not have preexisting heart disease. In one of these children, GABHS endocarditis was preceded by varicella. These cases indicate that GABHS is capable of causing endocarditis in the absence of heart disease, and they provide further evidence that varicella is an important risk factor for invasive GABHS infections.

Endocarditis, Bacterial↗
PubMed1999

Consumer perceptions of involuntary outpatient commitment.

This study examined beliefs about the provisions of outpatient commitment and their effects among 306 people with severe and persistent mental illness who were awaiting a period of outpatient commitment. More than 80 percent of the respondents perceived that the court order for outpatient commitment required them to keep their appointments at the mental health center and to take medication as prescribed. More than three-quarters believed that the outpatient commitment order made it more likely that people would keep their mental health appointments, take their medication, and stay out of the hospital.

Adult↗
PubMed1998

Induction of chromosome aberrations in peripheral blood lymphocytes after short time inhalation of nitric oxide.

INTRODUCTION: inhalation of nitric oxide (INO) leads to vasodilation of pulmonary vasculature in ventilated regions of the lung. The clinical use of INO, although not formally approved as a drug, is widespread. NO may rapidly form nitrogen dioxide (NO2) in an oxygen containing gas mixture. NO2 has been shown to induce chromosome aberrations and mutations in both animal and bacterial test systems. We investigated whether a 2-h exposure to NO would increase frequencies of cells with chromosome aberrations in peripheral blood lymphocytes of human volunteers. METHODS: 10 volunteers were exposed to inhaled NO 40 parts per million (ppm) for 2 h. Pre- and post-exposure blood samples were analysed. RESULTS: no statistically significant differences (p</=0.05) in chromosome aberrations were observed between pre- and post-exposure samples. CONCLUSION: no detectable increase of chromosome aberrations in human peripheral blood lymphocytes after 2 h of NO-inhalation 40 ppm was found.

Administration, Inhalation↗
PubMed1998

Role of acid and salivary epidermal growth factor in gastric mucosal adaptation to naproxen in man.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) frequently damage the gastrointestinal tract, but with continued administration this usually resolves by a process of adaptation. There is evidence that the acute injury can be reduced by acid suppression, and animal models have shown that salivary epidermal growth factor (EGF) is an important factor in gastric mucosal adaptation. We therefore wanted to assess the effect of acid suppression and salivary EGF output during naproxen-induced acute gastric injury and subsequent adaptation. METHODS: Healthy subjects were given a 14-day course of naproxen with different regimens of ranitidine and placebo. Before and on three occasions during treatment subjects provided a salivary sample for EGF and underwent gastroscopy to assess gastric damage. RESULTS: Similar gastric damage occurred after 24 h in all groups and resolved in most subjects. Base-line salivary EGF output was similar in all groups but increased in the placebo/ranitidine group on day 3 and in the ranitidine group on day 9. CONCLUSIONS: Acid suppression with ranitidine did not prevent acute gastric injury. Adaptation may be associated with an increase in salivary EGF output.

Adaptation, Physiological↗
PubMed1998

The usefulness of a structured questionnaire in the assessment of symptomatic gastroesophageal reflux disease.

BACKGROUND: The diagnosis of gastroesophageal reflux disease (GERD) rests primarily on recognition of symptom patterns that are classical for reflux disease, but little attention has been paid to the use of a formal questionnaire for identifying such symptom patterns. METHODS: A self-administered questionnaire was developed which has seven items that focus on the nature of the symptoms and the precipitating, exacerbating, and relieving factors. The diagnostic validity of the questionnaire was tested against endoscopy and 24-h pH monitoring. A further evaluation was undertaken in patients with symptoms suggestive of GERD and in patients with non-ulcer dyspepsia, to identify factors that might predict symptom relief during treatment with omeprazole. RESULTS: When endoscopic esophageal mucosal breaks and 24-h pH data were used as criteria for the diagnosis of GERD, the questionnaire had a sensitivity of 92% but a very low specificity of 19%. Symptom relief during treatment with omeprazole was predicted by the presence of heartburn, described as 'a burning feeling rising from the stomach or lower chest up towards the neck' (P = 0.004), and 'relief from antacids' (P = 0.02). In non-ulcer dyspepsia a positive response to omeprazole was confined to the subgroup of patients who identified their main discomfort as heartburn as described above. CONCLUSION: The present questionnaire using descriptive language usefully identified heartburn in patients presenting with upper abdominal symptoms, and this symptom predicted symptom resolution during treatment with omeprazole.

Anti-Ulcer Agents↗
PubMed1998

Gastro-oesophageal reflux disease in primary care: an international study of different treatment strategies with omeprazole. International GORD Study Group.

OBJECTIVE: To assess the efficacy of omeprazole in patients presenting with troublesome reflux symptoms. DESIGN: Randomized, double-blind, parallel-group, placebo-controlled comparison. SETTING: Primary care. SUBJECTS: Patients were recruited using a symptom-based questionnaire for diagnosis of gastro-oesophageal reflux disease. INTERVENTIONS: After endoscopy, patients without endoscopic oesophagitis were randomized to omeprazole 20 mg (Ome20), omeprazole 10 mg (Ome10) or placebo once daily for 4 weeks (n = 261) and those with oesophagitis (except circumferential/ulcerative) were randomized to receive either Ome20 or Ome10 once daily for 4 weeks (n = 277). Patients not symptom-free at 4 weeks received open treatment with Ome20 once daily for a further 4 weeks. Those symptom-free at 4-8 weeks were followed up for 6 months off treatment, to see whether their symptoms recurred. MAIN OUTCOME MEASURE: Complete upper GI symptom relief during week 4 on Ome20 or Ome10 in patients with or without endoscopic oesophagitis. RESULTS: Forty one percent of all patients on Ome20 and 35% on Ome10 reported complete relief from upper GI symptoms during week 4, whilst 73% of the patients on Ome20 and 62% on Ome10 obtained sufficient control. Complete relief during week 4 was reported by 19% of endoscopy-negative patients on placebo, and sufficient control by 35%. Endoscopic healing at 4 weeks occurred in 76% of oesophagitis patients on Ome20 and in 56% on Ome10. After 6 months off treatment, 90% of patients with oesophagitis and 75% of endoscopy-negative patients reported symptomatic relapse. CONCLUSION: Both 10 mg and 20 mg of omeprazole gave effective relief of symptoms, although 20 mg gave superior healing in patients with oesophagitis. After cessation of treatment, symptomatic relapse was rapid and frequent in both endoscopy-positive and endoscopy-negative patients.

Adolescent↗
PubMed1997

Industrial Genotoxicology Group collaborative trial to investigate cell cycle parameters in human lymphocyte cytogenetics studies.

Human lymphocyte cultures have been used for many years for assessing the in vitro clastogenic potential of test substances. In these assays the harvest time should be based on the cell cycle time in order to ensure that cells are sampled at an appropriate time for the detection of clastogenic effects. The sources of variation in the cell cycle time in routine cytogenetic assays have not been well studied. Consequently 13 laboratories, all members of the Industrial Genotoxicology Group, participated in a collaborative study to measure the variation in cell cycle time in cultured human peripheral blood lymphocytes under various conditions. The study was performed in two phases, spaced 6 months apart. The average generation time (AGT) was measured by the incorporation of bromodeoxyuridine. Very similar AGTs were found in the presence and absence of S9 mix. The mean AGT (mean of four donors) in each laboratory varied from 11.2 to 17.1 h, indicating there is significant variability in cell cycle times of human peripheral blood lymphocytes between laboratories. There was greater variation between laboratories than within laboratories. A comparison of AGT values at 72 h performed in experiments at least 6 months apart indicated good reproducibility in most laboratories. The study indicates that a 24 h post-treatment harvest may result in the analysis of very few first division cells unless very significant cell cycle delay is induced by the test substance. It was also found that a post-harvest time equivalent to 1.5 cell cycles will result in an approximately equal mixture of first and second division cells and therefore should by suitable for assessing both the induction of chromosome aberrations and polyploidy.

Animals↗