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Biomedical subjects

R Logan

Publications and source records attributed to R Logan.

At least 37 records · Page 2Linked to original sources
PubMed1996

Variability in risk of gastrointestinal complications with individual non-steroidal anti-inflammatory drugs: results of a collaborative meta-analysis.

OBJECTIVE: To compare the relative risks of serious gastrointestinal complications reported with individual non-steroidal anti-inflammatory drugs. DESIGN: Systematic review of controlled epidemiological studies that found a relation between use of the drugs and admission to hospital for haemorrhage or perforation. SETTING: Hospital and community based case-control and cohort studies. MAIN OUTCOME MEASURES: (a) Estimated relative risks of gastrointestinal complications with use of individual drugs, exposure to ibuprofen being used as reference; (b) a ranking that best summarised the sequence of relative risks observed in the studies. RESULTS: 12 studies met the inclusion criteria. 11 provided comparative data on ibuprofen and other drugs. Ibuprofen ranked lowest or equal lowest for risk in 10 of the 11 studies. Pooled relative risks calculated with exposure to ibuprofen used as reference were all significantly greater than 1.0 (interval of point estimates 1.6 to 9.2). Overall, ibuprofen was associated with the lowest relative risk, followed by diclofenac. Azapropazone, tolmetin, ketoprofen, and piroxicam ranked highest for risk and indomethacin, naproxen, sulindac, and aspirin occupied intermediate positions. Higher doses of ibuprofen were associated with relative risks similar to those with naproxen and indomethacin. CONCLUSIONS: The low risk of serious gastrointestinal complications with ibuprofen seems to be attributable mainly to the low doses of the drug used in clinical practice. In higher doses ibuprofen is associated with a similar risk to other non-steroidal anti-inflammatory drugs. Use of low risk drugs in low dosage as first line treatment would substantially reduce the morbidity and mortality due to serious gastrointestinal toxicity from these drugs.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Incidence of inflammatory bowel disease across Europe: is there a difference between north and south? Results of the European Collaborative Study on Inflammatory Bowel Disease (EC-IBD).

BACKGROUND: It has been suggested that the incidence of inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is three or more times higher in northern than in southern Europe. The aim of this EC funded study was to investigate this apparent variation by ascertaining the incidence of IBD across Europe. METHODS: For the period 1 October 1991 to 30 September 1993 all new patients diagnosed with IBD were prospectively identified in 20 European centres according to a standard protocol for case ascertainment and definition. FINDINGS: Altogether 2201 patients aged 15 years or more were identified, of whom 1379 were diagnosed as UC (including proctitis), 706 as CD, and 116 as indeterminate. The overall incidence per 100,000 at ages 15-64 years (standardised for age and sex) of UC was 10.4 (95% confidence interval (95% CI) 7.6 to 13.1) and that of CD was 5.6 (95% CI 2.8 to 8.3). Rates of UC in northern centres were 40% higher than those in the south (rate ratio (RR) = 1.4 (95% CI 1.2 to 1.5)) and for CD they were 80% higher (RR = 1.8 (95% CI 1.5 to 2.1)). For UC the highest reported incidence was in Iceland (24.5, 95% CI 17.4 to 31.5) and for CD, Maastricht (The Netherlands; 9.2, 95% CI 6.5 to 11.8) and Amiens (north west France; 9.2, 95% CI 6.3 to 12.2). The lowest incidence of UC was in Almada (southern Portugal) (1.6, 95% CI 0.0 to 3.2) and of CD in Ioannina (north west Greece) (0.9, 95% CI 0.0 to 2.2). An unexpected finding was a difference in the age specific incidence of UC in men and women with the incidence in women but not men declining with age. INTERPRETATION: The higher overall incidence rates in northern centres did not seem to be explained by differences in tobacco consumption or education. Nevertheless, the magnitude of the observed excess for both conditions is less than expected on the basis of previous studies. This may reflect recent increases in the incidence of IBD in southern Europe whereas those in the north may have stabilised.

Adolescent↗
PubMed1995

Prophylactic aspirin and risk of peptic ulcer bleeding.

OBJECTIVE: To determine the risks of hospitalisation for bleeding peptic ulcer with the current prophylactic aspirin regimens of 300 mg daily or less. DESIGN: A case-control study with hospital and community controls. SETTING: Hospitals in Glasgow, Newcastle, Nottingham, Oxford, and Portsmouth. SUBJECTS: 1121 patients with gastric or duodenal ulcer bleeding matched with hospital and community controls. RESULTS: 144 (12.8%) cases had been regular users of aspirin (taken at least five days a week for at least the previous month) compared with 101 (9.0%) hospital and 77 (7.8%) community controls. Odds ratios were raised for all doses of aspirin taken, whether compared with hospital or community controls (compared with combined controls: 75 mg, 2.3 (95% confidence interval 1.2 to 4.4); 150 mg, 3.2 (1.7 to 6.5); 300 mg, 3.9 (2.5 to 6.3)). Results were not explained by confounding influences of age, sex, prior ulcer history or dyspepsia, or concurrent non-aspirin non-steroidal anti-inflammatory drug use. Risks seemed particularly high in patients who took non-aspirin non-steroidal anti-inflammatory drugs concurrently. CONCLUSION: No conventionally used prophylactic aspirin regimen seems free of the risk of peptic ulcer complications.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Tissue ablation by a free-electron laser tuned to the amide II band.

Efforts to ablate soft tissue with conventional lasers have been limited by collateral damage and by concern over potential photochemical effects. Motivated by the thermal-confinement model, past infrared investigations targeted the OH-stretch mode of water with fast pulses from lasers emitting near 3,000 nm (refs 1, 7-9). What does a free-electron laser offer for the investigation of tissue ablation? Operating at non-photochemical single-photon energies, these infrared sources can produce trains of picosecond pulses tunable to the vibrational modes of proteins, lipids and/or water. We report here that targeting free-electron laser radiation to the amide II band of proteins leads to tissue ablation characterized by minimal collateral damage while maintaining a substantial ablation rate. To account for these observations we propose a novel ablation mechanism based on compromising tissue through resonant denaturation of structural proteins.

Amides↗
PubMed1994

Prognostic factors in upper gastrointestinal bleeding.

In this study we examined factors of possible prognostic value about outcome in a consecutive series of 2217 patients with hematemesis and melena. Death occurred in 189 (8.5%) patients, and 243 (11%) patients experienced rebleeding. Death was significantly associated with rebleeding, age over 60 years, and the finding of blood in the stomach at endoscopy. Rebleeding was significantly associated with melena, identification of a gastric or duodenal ulcer, endoscopic stigmata of hemorrhage such as blood, clot, and active bleeding, and the finding of shock at admission. However, female gender, previous history of ulceration, or indigestion of ulcerogenic drugs, especially nonsteroidal antiinflammatory drugs, were poor predictors of either death or rebleeding. We conclude that the identification of patients at a high risk could contribute to improved management of patients with gastrointestinal bleeding, including early therapeutic intervention.

Aged↗
PubMed1992

Plasmid cloning vectors for the conjugal transfer of DNA from Escherichia coli to Streptomyces spp.

We have constructed cloning vectors for the conjugal transfer of DNA from Escherichia coli to Streptomyces spp. All vectors contain the 760-bp oriT fragment from the IncP plasmid, RK2. Transfer functions need to be supplied in trans by the E. coli donor strain. We have incorporated into these vectors selectable antibiotic-resistance markers (AmR, ThR, SpR) that function in Streptomyces spp. and other features that should allow for: (i) integration via homologous recombination between cloned DNA and the Streptomyces spp. chromosome, (ii) autonomous replication, or (iii) site-specific integration at the bacteriophage phi C31 attachment site. Shuttle cosmids for constructing genomic libraries and bacteriophage P1 cloning vector capable of accepting approx. 100-kb fragments are also described. A simple mating procedure has been developed for the conjugal transfer of these vectors from E. coli to Streptomyces spp. that involves plating of the donor strain and either germinated spores or mycelial fragments of the recipient strain. We have shown that several of these vectors can be introduced into Streptomyces fradiae, a strain that is notoriously difficult to transform by PEG-mediated protoplast transformation.

Bacteriophages↗
PubMed1990

Rising mortality from cryptogenic fibrosing alveolitis.

OBJECTIVE: To determine the pattern of mortality ascribed to cryptogenic fibrosing alveolitis and to identify factors that might be important in the aetiology of the disease; and to assess the validity of death certification of the disease. DESIGN: A retrospective examination of mortality ascribed to cryptogenic fibrosing alveolitis in England and Wales between 1979 and 1988 with analysis, by multiple logistic regression, of independent effects of age, sex, region of residence, and social class as indicated by occupation on data for 1979-87; also a retrospective review of hospital records of patients certified as having died of cryptogenic fibrosing alveolitis in Nottingham and of the certified cause of death of patients known to have had the disease. MAIN OUTCOME MEASURES: Time trends in mortality nationally; effects on mortality of age, sex, and region of residence; validity of death certification in Nottingham. RESULTS: The annual number of deaths ascribed to cryptogenic fibrosing alveolitis doubled from 336 in 1979 to 702 in 1988, the increase occurring mainly at ages over 65. Mortality standardised for age for both sexes likewise increased steadily over the period. Deaths due to cryptogenic fibrosing alveolitis were commoner in men (odds ratio 2.24, 95% confidence interval 2.11 to 2.33) and increased substantially with age, being 7.84 (7.24 to 8.49) times higher in subjects aged much greater than 75 than those aged 45-64. Odds ratios of death due to cryptogenic fibrosing alveolitis adjusted for age and sex were increased in the traditionally industrialised central areas of England and Wales (p less than 0.02, maximum odds ratio between regions 1.25), but no significant increase in odds of death was found for manual occupations. Of 23 people whose deaths were registered in Nottingham as having been due to cryptogenic fibrosing alveolitis, 19 were ascertained from clinical records to have had the disease. Only 17 of 45 patients known to have had cryptogenic fibrosing alveolitis in life were recorded as having died from the disease. CONCLUSIONS: The diagnostic accuracy of death certification of cryptogenic fibrosing alveolitis is high, but the number of deaths recorded as being due to the disease may underestimate the number of patients dying with the disease by up to half. Mortality due to the disease is increasing, and the male predominance and regional differences in mortality suggest that environmental factors are important in its aetiology.

Adolescent↗
PubMed1988

Patient and spouse responses to education early after myocardial infarction.

The impact of a post myocardial infarction education programme was assessed by comparing the increase in knowledge of patients and spouses about CHD in two hospitals, one (A) with and the other (B) without such a programme. Subjects completed the same two questionnaires twice, once within 4 days of admission and again within 16 days of leaving hospital. Q1 contained 83 questions about CHD and Q2, consisted of seven questions of immediate practical relevance to their convalescence. When the two hospitals were compared the only significant changes were observed in the responses of spouses and patients from hospital A. Spouses in A increased their scores on Q1 by a mean of 7.13% (p 0.001) in contrast to a fall of 2.01% in B. The mean increase in scores on Q2 for patients in A was 19.3% (p 0.001). It is concluded that an education programme increases the knowledge of patients and spouses but that their learning ability differs. Whilst it is suggested that spouses are included in patient education it appears likely that their educational needs may differ from those of the patient.

Adult↗
PubMed1987

Newborn granulosa cell tumor of the testis.

We describe a male newborn who presented with a nodular mass in the right testicle. The alpha-fetoprotein level was greater than 450 ng. per ml. Scrotal ultrasound showed a multicystic "swiss-cheese"-appearing mass replacing most of the testicle, which suggested a teratoma. An operation was postponed until the physiological jaundice subsided. At orchiectomy a juvenile granulosa cell tumor of the testis was removed.

Granulosa Cell Tumor↗
PubMed1987

Biosynthetic studies on antibiotic A47934.

A47934, a peptide antibiotic produced by Streptomyces toyocaensis, belongs to the glycopeptide class of compounds which includes ristocetin and vancomycin. Incorporation studies with radioisotope-labeled substrates indicated that tyrosine, p-hydroxyphenylglycine, p-hydroxyphenylglyoxylate, acetate, and sulfate were efficiently incorporated into A47934. This is consistent with the reported biosynthesis of other glycopeptide antibiotics. Prototrophic mutants blocked in antibiotic biosynthesis were isolated at a low frequency (0.4%) after mutagenesis. Secretor-convertor pairings of the 36 mutants obtained demonstrated that they belonged to three classes: two groups of secretor-convertor pairs and a larger group of mutants that did not make antibiotic under any condition tested. Neither the secretor-convertor studies not supplementation of the cultures with putative biosynthetic intermediates was useful in identifying the location of the biosynthetic blocks. All studies to determine the timing of the sulfate addition step in the biosynthesis indicated that the sulfate is added prior to the formation of intermediates that possess antimicrobial activity.

Anti-Bacterial Agents↗
PubMed1986

Rising frequency of ulcer perforation in elderly people in the United Kingdom.

Peptic ulcer admission rates were known to be declining in England and Wales in younger men and women at least until 1977, but rates in elderly men were stable and rates in older women were increasing. Analysis of the most recently available data shows that these trends have continued in England and Wales and similar trends are seen in the elderly populations in Scotland. Reasons for the increasing susceptibility of elderly people, particularly older women, to peptic ulceration are not clear. However, altered smoking habits seem unlikely to explain the change, whereas increased use of non-steroidal anti-inflammatory drugs may account for part of it.

Adolescent↗