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Stewart L, Alton H, Desai M, van Mourik I. 195 The Stewart Ultrasound Score (SUSS): a new tool for quantitative assessment of CFLD. J Cyst Fibros 2007. [DOI: 10.1016/s1569-1993(07)60178-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
BACKGROUND It has been suggested that a time-lag bias exists whereby research studies with striking results are more likely to be stopped earlier than originally planned, published quicker, or both. If time-lag bias exists, new interventions might be mistakenly assumed to be effective. OBJECTIVES To study the extent to which time to publication of a clinical trial is influenced by the significance of its result. SEARCH STRATEGY Studies were identified by searching the Cochrane Methodology Register (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to May 2005), EMBASE (1980 to May 2005), Science Citation Index (June 2005) and by handsearching journals and conference abstracts. SELECTION CRITERIA Studies were eligible if they contained analyses of any aspect of the time to publication of clinical trials and tracked the publication of a cohort of clinical trials. DATA COLLECTION AND ANALYSIS Data extraction was performed independently by two authors. Data were extracted on the median time from the date the trial started to the date of publication. Data were also extracted on source of trials under investigation; source of funding; area of health care; means by which the publication status of these trials were sought; and methodological quality of the empirical study. MAIN RESULTS Two studies with a total of 196 trials met the inclusion criteria. In both studies just over half of all trials had been published in full. Trials with positive results (i.e. statistically significant in favour of the experimental arm) were published in approximately 4 to 5 years. Trials with null or negative results (i.e. not statistically significant or statistically significant in favour of the control arm) were published after about 6 to 8 years. One study suggested that this difference could, in part, be attributed to the length of time taken to publish the results of a trial once follow up has been completed. This study showed that trials with null or negative findings took, on average, just over a year longer to be published than those with positive results. AUTHORS' CONCLUSIONS Our review shows that trials with positive results are published sooner than other trials. This has important implications for the timing of the initiation and updating of a review, especially if there is an association between the inclusion of a trial in a review and its publication status. It is of particular concern when one considers reviews containing only a small number of studies.
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Stewart L, Gibson JNA, Thomson CE. In-shoe pressure distribution in "unstable" (MBT) shoes and flat-bottomed training shoes: a comparative study. Gait Posture 2007; 25:648-51. [PMID: 16901702 DOI: 10.1016/j.gaitpost.2006.06.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 06/09/2006] [Accepted: 06/12/2006] [Indexed: 02/02/2023]
Abstract
BACKGROUND Footwear comfort in many clinical situations is dependent on the ability of the 'shoe' to redistribute plantar pressure. Offloading the metatarsal heads may be achieved by fitting an insole, but recently a new design of shoe with a curved under sole (Masai Barefoot Technology or "MBT shoe") has been advocated. The aim of this study was to directly assess the effect of such shoes on gait pattern. METHODS Normal subjects were recruited and asked to walk sequentially in (a) flat-soled training shoes and (b) midfoot bearing shoes (MBT shoe). Mean and peak pressures in four anatomically defined areas of the foot, and the total area of sole contact were measured electronically by an in-shoe system (Pedar Ltd., UK). PRINCIPAL RESULTS Standing in the Masai shoes resulted in a 21% lesser peak pressure under the midfoot and an 11% lesser peak pressure under the heel in comparison to the figures found when patients wore their training shoes. There was a 76% compensatory increase in pressure under the toes. In essence there was a significant shift in pressure towards the front of the foot.
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Covar R, Macomber B, Stewart L, Gleason M, Engelhardt K, Murphy J, Liu A, Wood S, DeMichele S, Gelfand E, Szefler S. Effect of a Novel Medical Food (NMF) on Biomarkers of Inflammation and Airway Hyperresponsiveness in Children with Mild Persistent Asthma. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.12.343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Szefler S, Covar R, Macomber B, Stewart L, Gleason M, Engelhardt K, Murphy J, Liu A, Wood S, DeMichele S, Wennberg A, Gelfand E. Safety and Tolerance of a Novel Medical Food (NMF) in Children with Mild Persistent Asthma. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2006.12.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Alhasso AA, McKinlay J, Patrick K, Stewart L. Anticholinergic drugs versus non-drug active therapies for overactive bladder syndrome in adults. Cochrane Database Syst Rev 2006:CD003193. [PMID: 17054163 DOI: 10.1002/14651858.cd003193.pub3] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Overactive Bladder Syndrome (OAB) is defined as urgency, with or without urgency incontinence, usually with frequency and nocturia. Pharmacotherapy with anticholinergic drugs is often the first line medical therapy, either alone or as an adjunct to various non-pharmacological therapies. The commonest non-pharmacologic therapies are: bladder training, pelvic floor muscle training with or without biofeedback and electric stimulation to affect detrusor muscle activity. OBJECTIVES To compare the effects of various anticholinergic drugs with various non-pharmacologic therapies for idiopathic overactive bladder syndrome in adults. SEARCH STRATEGY We searched the Cochrane Incontinence Group Specialised Register (searched 29 November 2005), The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (January 1966 to September 2004), PREMEDLINE, Dissertation Abstracts and the reference lists of relevant articles. SELECTION CRITERIA All randomised, or quasi-randomised, controlled trials of treatment with anticholinergic drugs for overactive bladder syndrome or urge urinary incontinence in adults, in which at least one management arm involved a non-drug new therapy. Trials amongst patients with neuropathic bladder dysfunction were excluded. DATA COLLECTION AND ANALYSIS Two authors evaluated the trials for appropriateness for inclusion and methodological quality. Three authors were involved in the data extraction. Data extracted was based on predetermined criteria. Data analysis was based on standard statistical approaches used in Cochrane reviews. MAIN RESULTS Thirteen trials with 1770 participants were included; all were designed as parallel groups except for one cross-over trial. Trial groups were well matched for baseline characteristics in all trials. Treatment duration was 3 to 12 weeks, with one trial carrying out a follow-up analysis at 24 weeks after starting treatment. During treatment, symptomatic improvement was more common amongst those on anticholinergic drugs compared with bladder training (RR 0.73; 95% CI 0.59 to 0.90). Combination of anticholinergics with bladder training was also associated with more improvement than bladder training alone but with wide confidence intervals (RR 0.55; 95% 0.32 to 0.93). Similarly, the limited data favoured a combination of anticholinergics with bladder training compared with anticholinergics during treatment but the difference was not statistically significant (RR for improvement 0.81; 95% CI 0.61 to 1.06). For all comparisons, there were too few data to compare symptoms after treatment had ended. Adverse effects, such as dry mouth, were reported by around a third of those taking anticholinergics. AUTHORS' CONCLUSIONS The use of anticholinergic drugs in the management of OAB is well established. During initial treatment there was more symptomatic improvement when (a) anticholinergics were compared with bladder training alone, and (b) anticholinergics combined with bladder training were compared with each modality alone. Anticholinergics have well recognised side effects, such as dry mouth. There were too few data to assess whether or not effects are sustained after stopping treatment.
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Carpenter A, Finley E, Gao Y, Lin C, Nuding A, Shaheen P, Stewart L, Sun X, Taranto M, Tilley A, Waggoner L, Xu H, Vidra RL. Ethics: Developing a Code of Ethics for Restorationists. ECOL RESTOR 2006. [DOI: 10.3368/er.24.2.105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Ainsworth SB, Humphreys R, Stewart L. The pressure is on! The danger of a broken blow off valve on a bag valve mask. Arch Dis Child Fetal Neonatal Ed 2006; 91:F233. [PMID: 16632656 PMCID: PMC2672712 DOI: 10.1136/adc.2005.076018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Stewart L, Mjaanes C, Gleason M, Covar R, Spahn J. Is Wheezing the Best Endpoint for Bronchial Challenges in Young Children? J Allergy Clin Immunol 2006. [DOI: 10.1016/j.jaci.2005.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Staker BL, Feese MD, Zembower D, Stewart L, Burgin AB. Multiple inhibitor co-crystal structures of the human topoisomerase I covalent DNA complex bound to a series of structurally diverse anti-cancer compounds. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305089518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Burdett S, Stewart L. P-705 Postoperative radiotherapy in non-small-cell lung cancer: An update of a systematic review and individual patient data meta-analysis. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)81198-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Burdett S, Auperin A, Stewart L, Pignon J. P-202 Chemotherapy in non-small cell lung cancer (NSCLC): An individual patient data meta-analysis. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80696-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Vale C, Stewart L, Tierney J. Trends in UK cancer trials: results from the UK Coordinating Committee for Cancer Research National Register of Cancer Trials. Br J Cancer 2005; 92:811-4. [PMID: 15756251 PMCID: PMC2361907 DOI: 10.1038/sj.bjc.6602425] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We aimed to study trends in the design and conduct of randomised controlled trials (RCTs) in cancer in the UK, using the UK Coordinating Committee for Cancer Research (UKCCCR) National Register of Cancer Trials (NRCT). We conducted a descriptive survey of 520 UK RCTs in cancer that were registered on the UKCCCR NRCT. All trials had been initiated between 1971 and 2000. Trials on the NRCT have been conducted in a wide variety of cancer types, but with a third in breast (22%) or lung cancer (11%). They have largely been funded by the UK public and charity sectors. Overall, there has been a sustained rise in the total numbers of patients entering UK cancer trials over time with a trend towards larger, multicentre trials, greater recruitment targets and a marked reduction in the average time taken to complete trials. Trends in the design and conduct of noncommercial cancer RCTs from 1971 to 2000 are encouraging. It will be interesting to see how they develop in light of the implementation of recent national initiatives regarding cancer clinical trials in the UK.
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Zioutas K, Andriamonje S, Arsov V, Aune S, Autiero D, Avignone FT, Barth K, Belov A, Beltrán B, Bräuninger H, Carmona JM, Cebrián S, Chesi E, Collar JI, Creswick R, Dafni T, Davenport M, Di Lella L, Eleftheriadis C, Englhauser J, Fanourakis G, Farach H, Ferrer E, Fischer H, Franz J, Friedrich P, Geralis T, Giomataris I, Gninenko S, Goloubev N, Hasinoff MD, Heinsius FH, Hoffmann DHH, Irastorza IG, Jacoby J, Kang D, Königsmann K, Kotthaus R, Krcmar M, Kousouris K, Kuster M, Lakić B, Lasseur C, Liolios A, Ljubicić A, Lutz G, Luzón G, Miller DW, Morales A, Morales J, Mutterer M, Nikolaidis A, Ortiz A, Papaevangelou T, Placci A, Raffelt G, Ruz J, Riege H, Sarsa ML, Savvidis I, Serber W, Serpico P, Semertzidis Y, Stewart L, Vieira JD, Villar J, Walckiers L, Zachariadou K. First results from the CERN axion solar telescope. PHYSICAL REVIEW LETTERS 2005; 94:121301. [PMID: 15903903 DOI: 10.1103/physrevlett.94.121301] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2004] [Indexed: 05/02/2023]
Abstract
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.
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Tavernier GOG, Fletcher GD, Francis HC, Oldham LA, Fletcher AM, Blacklock G, Stewart L, Gee I, Watson A, Frank TL, Frank P, Pickering CAC, Niven RML. Endotoxin exposure in asthmatic children and matched healthy controls: results of IPEADAM study. INDOOR AIR 2005; 15 Suppl 10:25-32. [PMID: 15926941 DOI: 10.1111/j.1600-0668.2005.00354.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
UNLABELLED Children spend increasing time indoors. Exposure to environmental factors may contribute to the development or exacerbation of the asthmatic phenotype. Inter-relationships between these factors might influence the manifestation of asthma. Endotoxin exposure has been shown to have pro-inflammatory and protective effects in different situations. We investigated the exposure to several indoor pollutants (endotoxin, Der p 1, damp, ETS, PM2.5) in asthmatic and healthy children. The children were recruited from two primary care centers according to their response to a validated questionnaire. Asthmatic children were matched for sex, age and sib-ship size with children living in asthma free households. Of 90 matched pairs, higher levels of endotoxin were found in the living room carpets, but not the bedroom carpet or mattresses of the asthma compared with the control homes (STATA analysis OR: 1.88 (1.11-3.18); P=0.018). Asthmatic children were also more likely to live as part of a single parent family, in a house where the parents self-reported the presence of damp, and where the living room had been redecorated in the 12 months prior to the sampling visits. This study suggests that endotoxin in urban homes is a risk factor for the development of asthma. Moreover, this study found that there were no statistically significant interactions between environmental factors. PRACTICAL IMPLICATIONS This study has demonstrated that the home environments of English children (4-17) with asthma and without the disease do not differ greatly. With the exception of endotoxin, the parameters examined in this study, including house dust mite allergens, nitrogen dioxide, ETS and damp are unlikely to be related to the development of asthma. Avoidance of these pollutants may not be beneficial in preventing asthma in this age group.
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Hodges RA, Falta R, Stewart L. Controlling steam flood migration using air injection wells. ACTA ACUST UNITED AC 2004. [DOI: 10.1306/eg.06250404017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Papaioannou G, Mchugh K, Alton HM, Irwin GJ, Williams HJ, Foster K, Stewart L. Picture Quiz. IMAGING 2004. [DOI: 10.1259/imaging/17532144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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94
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Stewart L. The role of ultrasound in the investigation of childhood abdominal pain. IMAGING 2004. [DOI: 10.1259/imaging/64124181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Haab F, Stewart L, Dwyer P. Darifenacin, an M3 selective receptor antagonist, is an effective and well-tolerated once-daily treatment for overactive bladder. Eur Urol 2004; 45:420-9; discussion 429. [PMID: 15041104 DOI: 10.1016/j.eururo.2004.01.008] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To evaluate the efficacy, tolerability and safety of darifenacin, a once-daily M3) selective receptor antagonist (M3 SRA), in patients with overactive bladder (OAB). METHODS This multicentre, double-blind, placebo-controlled, parallel-group study enrolled 561 patients (19-88 years; 85% female) with OAB symptoms for >6 months, and included some patients with prior exposure to antimuscarinic agents. After washout and a 2-week placebo run-in, patients were randomised (1:4:2:3) to once-daily oral darifenacin controlled-release tablets (3.75 mg [n=53], 7.5 mg [229] or 15 mg [n=115]) or matching placebo (n=164) for 12 weeks. Patients recorded daily incontinence episodes, micturition frequency, bladder capacity (mean volume voided), frequency of urgency, severity of urgency, incontinence episodes resulting in change of clothing or pads and nocturnal awakenings due to OAB using an electronic diary during weeks 2, 6 and 12 (directly preceding clinic visits). Tolerability data were evaluated from adverse event reports. RESULTS Darifenacin 7.5 mg and 15 mg had a rapid onset of effect, with significant improvement compared with placebo being seen for most parameters at the first clinic visit (week 2). This effect was sustained through week 12. At this time the number of incontinence episodes per week was reduced from baseline by 67.7% with darifenacin 7.5 mg and 72.8% with darifenacin 15 mg compared with 55.9% with placebo (p=0.010 and p=0.017, respectively, versus placebo). The 3.75 mg group (null dose arm) was included for proof of concept of dose flexibility, therefore formal sample sizing and statistical analysis were not performed for this group. Darifenacin 7.5 mg and 15 mg, respectively, were significantly superior to placebo for improvements in micturition frequency (p<0.001, p<0.001), bladder capacity (p<0.040, p<0.001), frequency of urgency (p<0.001, p=0.005), severity of urgency (p<0.001, p=0.002) and number of incontinence episodes leading to a change in clothing or pads (p<0.001, p=0.002). There was no significant reduction in nocturnal awakenings due to OAB. The most common adverse events were mild-to-moderate dry mouth and constipation. However, no patients withdrew from the study as a result of dry mouth and discontinuation related to constipation was rare (0.6% placebo versus 0.9% darifenacin). In addition, there was a low need for laxative use, with no difference between the darifenacin groups and those taking placebo. There were no reports of blurred vision and the CNS and cardiac safety profile was comparable to placebo. CONCLUSIONS Darifenacin significantly improves the major symptoms of OAB. No significant CNS (primarily M1-receptor mediated) adverse events or cardiac (primarily M2-receptor mediated) adverse events were identified in this study, as may be predicted from the M3 selective receptor profile of darifenacin.
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Jayaprakash A, Creed T, Stewart L, Colton B, Mountford R, Standen G, Probert C. Should we monitor vitamin B12 levels in patients who have had end-ileostomy for inflammatory bowel disease? Int J Colorectal Dis 2004; 19:316-8. [PMID: 14618349 DOI: 10.1007/s00384-003-0556-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/25/2003] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS We examined whether vitamin B12 levels are low following surgery in those patients who have had end-ileostomy for inflammatory bowel disease. PATIENTS AND METHODS This prospective observational study used the database of a university teaching hospital to identify patients with inflammatory bowel disease with an end-ileostomy constructed more than 30 months previously. Precise diagnosis, disease distribution and details of their surgery were collected from case notes of the 39 eligible patients (18 Crohn's disease, 17 ulcerative colitis, 4 indeterminate colitis). Mean duration since ileostomy formation was 12.53 years. Patients found to be vitamin B12 deficient underwent further investigations to ascertain the cause of their vitamin B12 deficiency (<150 ng/l). RESULTS There was no significant difference between serum vitamin B12 levels in patients with Crohn's disease and those in patients with ulcerative colitis following end ileostomy formation. Two patients (5.1%) were identified as having vitamin B12 deficiency. One of these had had a panproctocolectomy for Crohn's disease, followed by subsequent resection for ileal obstruction and ongoing small intestinal disease. The other had had colectomy for ulcerative colitis, in whom no cause other than the ileostomy was found for the vitamin B12 deficiency. There was no significant correlation between serum vitamin B12 levels and duration of ileostomy overall or in the disease subgroups. CONCLUSION We do not recommend routine screening for vitamin B12 deficiency in this group of patients unless they have undergone additional small bowel resection or have ongoing small bowel inflammation.
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Dublin N, Alhasso AA, Stewart L. Anticholinergic drugs versus other medications for overactive bladder syndrome in adults. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2004. [DOI: 10.1002/14651858.cd003190.pub2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Patrick K, Alhasso AA, Stewart L. Anticholinergic drugs versus non-drug active therapies for overactive bladder syndrome in adults. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2004. [DOI: 10.1002/14651858.cd003193.pub2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Shi L, Yao J, Stewart L, Xu Z. Brain C-FOS expression and pressor responses after I.V. or I.C.V. angiotensin in the near-term ovine fetus. Neuroscience 2004; 126:979-87. [PMID: 15207331 DOI: 10.1016/j.neuroscience.2004.04.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2004] [Indexed: 11/23/2022]
Abstract
Fetal brain c-fos and cardiovascular responses after i.v. or i.c.v. angiotensin II administrations was determined in the near-term ovine fetuses. Both routes of angiotensin II markedly increased fetal mean arterial pressure. The latency of pressor responses by i.v. angiotensin II administration was shorter than by the i.c.v. route. The increased fetal mean arterial pressure was greater and transient by the i.v. route in comparison to that caused by i.c.v. angiotensin II administration. Following the i.v. administration of angiotensin II, the fetal heart rate was significantly decreased. Associated with fetal pressor responses and bradycardia, c-fos expression induced by i.v. angiotensin II was in the paraventricular nuclei (PVN) of the hypothalamus, and the area postrema, the tractus solitarius nuclei, and the lateral parabrachial nuclei in the brain stem. After i.c.v. angiotensin II administration, fetal blood pressure was also increased in association with the intensive c-fos expression in the PVN and the hindbrain. However, fetal heart rate was not affected by the central injection of angiotensin II. These results indicate that the central pathways between the forebrain circumventricular organs and the PVN have developed, and suggest that the neural activity in the hindbrain associated with bradycardia may be linked to the baroreflex. In the face of i.c.v. angiotensin II, sympathetic activation may play a predominant role in pressor responses. Taken together, these results suggest that central and peripheral angiotensin II-induced fetal pressor responses may be mediated by separate mechanisms, and these regulatory mechanisms start to function by near-term or early.
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