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Biomedical subjects

S Jones

Publications and source records attributed to S Jones.

At least 37 records · Page 2Linked to original sources
PubMed2005

Interaction between inorganic nutrients and organic matter in controlling coral reef communities in Glovers Reef Belize.

We studied the responses of algae, corals, and small fish to elevated inorganic fertilizer, organic matter, and their combination over a 49-day summer period in cages that simulated the coral reef in the remote Glovers reef atoll, Belize. The addition of organic matter reduced while fertilization had no effect on the numbers of herbivorous damsel and parrotfishes. All measures of algal biomass were influenced by fertilization. The combined inorganic and organic enrichment produced the highest algal biomass, which is most likely due to the combined effect of higher nutrients and lower herbivory. The cover of turf and total algae were influenced by all treatments and their interactions and most strongly and positively influenced by fertilization followed by organic matter and the combination of organic matter and inorganic fertilizer. The inorganic and combined treatments were both dominated by two turf algae, Enteromorpha prolifera and Digenia simplex, while the nonfertilized treatments were dominated by brown frondose algae Lobophora variegata, Padina sanctae, and Dictyota cervicornis. The organic matter treatment had greater cover of P. sanctae and D. cervicornis than the untreated control, which was dominated by Lobophora variegata, also the dominant algae on the nearby patch reefs. Crustose corallines grew slowly ( approximately 2.5 mm/49 days) and were not influenced by the treatments when grown on vertical surfaces but decreased on horizontal coral plates in the combined organic matter and fertilization treatment. No mortality occurred for the two coral species that were added to the cages. Porites furcata darkened in the fertilized cages while there was a mix of paling and darkening for a small amount of the coral tissue of Diploria labyrinthiformes. Inorganic fertilization stimulates small filamentous turf algae and Symbiodinium living in coral but inhibits brown frondose algae. Organic matter inhibits small herbivorous fish, L. variegata, and encrusting coralline algae when growing on horizontal surfaces.

Analysis of Variance↗
PubMed2005

L-carnitine and exercise tolerance in medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency: a pilot study.

Skeletal muscle function may be impaired in patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, but the value of L-carnitine in their long-term management is not clear. This study was designed as a pilot to examine the effects of L-carnitine on exercise tolerance in patients with MCAD deficiency. Four clinically asymoptomatic MCAD-deficient patients, aged 8 to 20 years, were studied. Incremental ramp exercise tests were carried out before and after 4 weeks' treatment with oral L-carnitine (100 mg/kg per day). During exercise without L-carnitine supplementation, plasma carnitine concentrations fell, associated with an increased excretion of urinary acylcarnitines, notably acetylcarnitine, hexanoylcarnitine and octanoylcarnitine. L-carnitine treatment prevented this fall in plasma carnitine and resulted in greater increases in excretion of acylcarnitines. All four patients showed biologically significant improvement in peak oxygen uptake (peak VO2, 18-32% improvement), VO2 at a heart rate of 170 beats/min (15-23% improvement), VO2 at anaerobic threshold (27-42% improvement), and/or oxygen pulse (10-32% improvement). Exercise tolerance in MCAD-deficient patients may be improved by short-term L-carnitine supplementation. This may be the direct result of improved intramitochondrial homeostasis induced by L-carnitine in removing accumulating acyl moieties.

3-Hydroxybutyric Acid↗
PubMed2005

MutYH (MYH) and colorectal cancer.

MAP (MutYH-associated polyposis) is a recently described colorectal adenoma and carcinoma predisposition syndrome that is associated with biallelic-inherited mutations of the human MutY homologue gene, MutYH. MutYH is often also termed MYH. MAP tumours display a mutational signature of somatic guanine-to-thymine transversion mutations in the adenomatous polyposis coli and K-ras genes, reflecting the normal role of MutYH in the base excision repair of adenines misincorporated opposite 7,8-dihydro-8-oxoguanine, a prevalent and stable product of oxidative damage to DNA. However, the full genetic pathway of MAP tumorigenesis has not been elucidated.

Adenomatous Polyposis Coli↗
PubMed2005

Looking at the future and seeing the past: the challenge of the middle years of parenting a child with intellectual disabilities.

BACKGROUND: This paper seeks to understand and conceptualize the experience of mothers of adolescents with intellectual disabilities (IDs) at a time in their lives which others have characterized as 'mid-life' or the 'middle years of parenting'. The concerns of the paper are the lifecourse concerns in mothers' own lives and with biographical elements of becoming and being such a parent. METHODS: Qualitative interviews were conducted with mothers of adolescents with IDs. The average age of mothers was 48 years. Typically parents were interviewed on two to three occasions. RESULTS: The data suggest that despite the difficulties they faced, these parents had constructed a 'life-as-ordinary' in the early phase of their parental careers. They saw themselves as 'ordinary mothers'. However, the social content and events of the middle years of parenting prompt a realization that their lives and, for some, their sense of 'self', are undergoing considerable change. Mothers are forced to look over their lives to find the meaning and significance of these events. For some, there is biographical reinforcement. For others, there is only disruption. DISCUSSION: The overall picture of these years is one of considerable changes and challenges, and underlines the need for a focus on the lifecourse concerns of parents as well as their children. The implications of the data for further research and service development are discussed in the context of identity theory.

Adaptation, Psychological↗
PubMed2005

Prevalence of, and risk factors for, hepatitis C virus infection among recent initiates to injecting in London and Glasgow: cross sectional analysis.

Our aim was to compare the prevalence of antibody to hepatitis C virus (anti-HCV) among recently initiated injecting drug users (IDUs) in London and Glasgow, and to identify risk factors which could explain differences in prevalence between the cities. Complementary studies of community recruited IDUs who had initiated injection drug use since 1996 were conducted during 2001-2002. Data on HCV risk behaviours were gathered using structured questionnaires with identical core questions and respondents were asked to provide an oral fluid specimen which was tested anonymously for anti-HCV but was linked to the questionnaire. Sensitivities of the anti-HCV assays for oral fluid were 92-96%. Prevalence of anti-HCV was 35% (122/354) in London and 57% (207/366) in Glasgow (P < 0.001). Multifactorially, factors significantly associated with raised odds of anti-HCV positivity were increasing length of injecting career, daily injection, polydrug use, having had a needlestick injury, and having served a prison sentence. In addition lower odds of anti-HCV positivity were associated with non-injection use of crack cocaine and recruitment from drug agencies. After adjustment for these factors, the increased odds of anti-HCV associated with being a Glasgow IDU were diminished but remained significant. HCV continues to be transmitted among the IDU population of both cities at high rates despite the availability of syringe exchange and methadone maintenance. Effectiveness of harm reduction interventions may be compromised by inadequate coverage and failure to reduce sufficiently the frequency of sharing different types of injecting equipment, as well as the high background prevalence of HCV, and its high infectivity. Comprehensive action is urgently required to reduce the incidence of HCV among injectors.

Adult↗
PubMed2005

Effect of E. coli Nissle 1917 on post-inflammatory visceral sensory function in a rat model.

OBJECTIVE: Visceral hyperalgesia (VH) plays a key role for the manifestation of functional gastrointestinal (GI) disorders. In a subgroup of patients, the initial manifestation is preceded by GI inflammation. Recent studies have demonstrated an improvement of inflammation and symptoms during treatment with Escherichia coli Nissle 1917 (EcN). AIM: We aimed to characterize the effects of EcN on visceral sensitivity in a rat model of post-inflammatory VH. METHODS: Male Lewis rats underwent colorectal instillation of trinitrobenzenesulphonic acid (TNBS) plus an equal amount of ethanol (test group) or physiological saline solution (control group). After 28, 35 and 42 days, standardized colorectal distensions were performed and the visceromotor reflex (VMR) of abdominal wall muscles was quantified by electromyographic recording. From day 28 onwards, EcN was administered in drinking water. RESULTS: After TNBS, a significant increase of VMR was observed compared with saline controls over all study days. Administration of EcN reduced the TNBS-induced hyperalgesia [EcN: 863+/-125 microV vs placebo: 1258+/-157 microV (P<0.05)] at day 35, while there were no significant alterations at any other study day. CONCLUSION: The EcN administration caused a significant reduction of VH. Whether EcN might play a role in the treatment of post-infectious functional bowel disorders remains to be investigated in further studies.

Animals↗
PubMed2005

Complications and mortality following stoma formation.

INTRODUCTION: As stoma formation is thought to be declining, we performed a study to evaluate the rate of stoma formation and the impact on stoma complication rates, together with risk factors for complications. PATIENTS AND METHODS: Stoma incidence, individual complications and mortality rates were retrieved from a stoma nurse database of 345 stomas created over an 8-year period. RESULTS: Stoma formation increased over the study period, although the incidence of complications declined. Stoma complications were more frequently seen in emergency surgery. A significant association between stoma complications and mortality was identified. CONCLUSIONS: Age of patient, urgency of surgery and diagnosis were associated with high levels of morbidity and mortality. Stomas are often formed in frail patients unsuitable for anastomosis formation, which may explain the high mortality in ostomy patients.

Adolescent↗
PubMed2005

Monitoring Escherichia coli O157:H7 in inoculated and naturally colonized feedlot cattle and their environment.

On-farm methods of monitoring Escherichia coli O157:H7 were assessed in 30 experimentally inoculated steers housed in four pens over a 12-week period and in 202,878 naturally colonized feedlot cattle housed in 1,160 pens on four commercial Alberta feedlots over a 1-year period. In the challenge study, yearling steers were experimentally inoculated with 10(10) CFU of a four-strain mixture of nalidixic acid-resistant E. coli O157:H7. After inoculation, shedding of E. coli O157:H7 was monitored weekly by collecting rectal fecal samples (FEC), oral swabs (ORL), pooled fecal pats (PAT), manila ropes (ROP) orally accessed for 4 h, feed samples, water, and water bowl interface. Collection of FEC from all animals per pen provided superior isolation (P < 0.01) of E. coli O157:H7 compared with other methods, although labor and animal restraint requirements for fecal sample collection were high. When one sample was collected per pen of animals, E. coli O157:H7 was more likely to be detected from the ROP than from the FEC, PAT, or ORL (P < 0.001). In the commercial feedlot study, samples were limited to ROP and PAT, and E. coli O157:H7 was isolated in 18.8% of PAT and 6.8% of ROP samples. However, for animals that had been resident in the feedlot pen for at least 1 month, isolation of E. coli O157:H7 from ROP was not different from that from PAT (P = 0.35). Pens of animals on feed for <30 days were six times more likely to shed E. coli O157:H7 than were animals on feed for >30 days. However, change in diet did not affect shedding of the organism (P > 0.23) provided that animals had acclimated to the feedlot for 1 month or longer. Findings from this study indicate the importance of introduction of mitigation strategies early in the feeding period to reduce transference and the degree to which E. coli O157:H7 is shed into the environment.

Alberta↗
PubMed2004

Positive, site-specific associations between bone mineral status, fitness, and time spent at high-impact activities in 16- to 18-year-old boys.

The incidence of hip and forearm fracture in elderly men in the United Kingdom is a public health issue, but there is limited knowledge on lifestyle factors affecting male bone health. The aim of this cross-sectional study was to evaluate the relationships between whole body and regional bone mineral status and self-reported participation time in no-, low-, moderate-, and high-impact activities and fitness measurements in 16- to 18-year-old boys. One hundred twenty-eight boys underwent absorptiometry (DXA) measurements (Hologic QDR 1000W) of bone mineral content (BMC), bone area (BA), and bone mineral density (BMD) at the whole body, hip, spine, and forearm. They also completed the EPIC (European Prospective Investigation of Cancer) physical activity questionnaire, which allowed categorization of activities according to impact and aerobic intensity. Fitness and strength were assessed in each subject using estimated VO2 max, grip strength, and back strength. Significant positive relationships were found between BMC, BA, and BMD and the fitness and strength measurements and participation time in high-impact sports at most skeletal sites. The relationships were further examined after adjustment of BMC for height, weight, and bone area, thereby minimizing the influence of body and bone size on these relationships. VO2 max was a significant positive determinant of size-adjusted BMC at the whole body, the ultradistal and one-third radius, and all the hip sites, except the trochanter. Size-adjusted BMC at the forearm sites and trochanter was significantly positively associated with grip strength. Size-adjusted BMC at the whole body and all the hip sites was significantly positively associated with time spent at high-impact activities. Differences in size-adjusted BMC across thirds of time spent at high-impact activities were also examined. Boys in the highest third of high-impact activity had significantly greater size-adjusted whole body BMC and total hip BMC compared to subjects in the lowest third [+3.4 (1.2)% for whole body and +8.5 (2.2)% for hip, both P = 0.001]. Boys in the highest third of high-impact activity spent most activity time jogging, playing tennis, football and rugby, basketball, and exercising with weights. Back strength and lean mass were significantly greater in subjects in the highest third compared to those in the middle (P = 0.02) and lowest third (P = 0.03). No significant differences were found between subjects in each third of high-impact activity for potential confounders including TV viewing, calcium intake, body fat, and height. These findings indicate that participation of male adolescents in a range of high-impact activities for 1 h or more a day is associated with greater bone size and mineral content, especially at the hip.

Adolescent↗
PubMed2004

Increased frequency of the k-ras G12C mutation in MYH polyposis colorectal adenomas.

Colorectal tumours from MYH polyposis patients display an excess of somatic G : C --> T : A transversions in the adenomatous polyposis coli gene. Here, we identify k-ras mutations in nine out of 54 (16.7%) MYH polyposis tumours. Their presence was associated with increased dysplasia and tubulovillous morphology (P=0.005). G : C --> T : A transversions in k-ras were significantly more frequent in MYH polyposis adenomas than in sporadic or familial adenomatous polyposis-associated tumours (P<or=0.002), and all resulted in a glycine-to-cysteine substitution at codon 12.

Adenoma↗
PubMed2004

Expression and characterisation of recombinant oligomeric envelope glycoproteins derived from primary isolates of HIV-1.

The production, purification and characterisation of recombinant gp140 oligomeric envelope glycoproteins derived from six primary isolates of HIV-1 (covering clades A, B, C, D, F and O) are described. Using a Chinese hamster ovary cell expression system, expression levels of between 0.1 and 1 mg/l cell-conditioned culture media were obtained, and purified to >95% by affinity chromatography. A, B, D, F and O clade gp 140s were found to be multimeric, bind to a panel of defined env-specific monoclonal antibodies and interact with CD4 and CXCR4, demonstrating correct folding. Their immunogenicity was confirmed by the generation of high-titre anti-gp140 antibodies in rabbits. The C clade gp140 was incorrectly folded and poorly antigenic. Despite the presence of an unmodified gp120/41 cleavage site, only the B clade gp140 showed significant processing to gp120 and gp41. Each gp140 has a specific pattern of oligomerisation, and varies in its resistance to reducing agents and salt concentration. The binding of gp140 to soluble and cell-surface CD4 and CXCR4 is related to the degree of oligomerisation. The C1 and C5 regions, CD4 binding domain and the epitope defined by the 2G12 monoclonal antibody were well exposed, but the C-terminal region of the extracellular domain of gp41 appears to be occluded by oligomerisation. These reagents have potential as immunogens for use in vaccine development.

Animals↗
PubMed2004

Improving the standard of operation notes in orthopaedic and trauma surgery: the value of a proforma.

Comprehensive documentation of surgical procedures is an essential component of good medical practice, but the standard of operation notes in orthopaedic and trauma surgery has been notoriously poor. The value of proformas in the production of high standard operation notes has been demonstrated in various surgical specialities. We have compared the standard of documentation of operation notes before and after the introduction of a proforma and report a significant improvement (P < 0.001) with the proforma. In addition, the results from a neighbouring hospital where a similar proforma was in use show a sustained standard of documentation 5 years after it was first used.

England↗
PubMed2004

Prevention of percutaneous endoscopic gastrostomy site infections caused by methicillin-resistant Staphylococcus aureus.

Percutaneous endoscopic gastrostomy (PEG) is widely used to maintain enteral nutrition in patients who are unable to swallow. Peristomal wound infection is the most common complication of this procedure. In a hospital endemic for methicillin-resistant Staphylococcus aureus (MRSA), MRSA can be the most common organism associated with these infections. We have evaluated a strategy consisting of screening, skin decontamination and glycopeptide prophylaxis for preventing PEG-site infections. None of the 34 patients who received the decontamination protocol and glycopeptide prophylaxis (Group A) developed PEG-site infections within one month of surveillance. Two patients were infected with MRSA after that period. One of seven patients who received the decontamination protocol alone (Group B) was infected within the period of surveillance, while another patient was infected after that period. Both were infected with MRSA. None of nine patients who received glycopeptide prophylaxis alone (Group C) were infected. The results suggest that the strategy of screening, decontamination and glycopeptide prophylaxis is effective in the prevention of PEG-site infections with MRSA. Further trials are necessary to confirm these findings.

Aged↗
PubMed2004

Rectal prolapse in autistic children.

Rectal prolapse in children is not uncommon, but surgery is rarely indicated. In mentally challenged adults and children, rectal prolapse occurs more frequently than in the general population and often requires surgical intervention in the second to third decade of life. The authors describe 3 children with autism and mental retardation who presented with rectal prolapse at an earlier age than would be anticipated with mental retardation alone. All 3 children required surgical intervention.

Age of Onset↗
PubMed2004

The impact of beliefs about mental health problems and coping on outcome in schizophrenia.

BACKGROUND: Using the theoretical framework of the Self Regulation Model (SRM), many studies have demonstrated that beliefs individuals hold about their physical health problems are important in predicting health outcomes. This study tested the SRM in the context of a mental health problem, schizophrenia. METHOD: One hundred and twenty-four people with a diagnosis of schizophrenia were assessed on measures of symptom severity, beliefs about their mental health problems, coping and appraisal of outcome at two time points, 6 months apart. RESULTS: Using multivariate analyses and controlling for severity of symptoms, beliefs about mental health were found to be significant predictors of outcome. Beliefs about greater negative consequences were the strongest and most consistent predictors of a poorer outcome in both cross-sectional and longitudinal analyses. CONCLUSIONS: These results suggest that the SRM is a promising model for mental health problems and may highlight important areas for development in clinical, and especially psychosocial interventions.

Adaptation, Psychological↗