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Biomedical subjects

N Saunders

Publications and source records attributed to N Saunders.

At least 37 records · Page 2Linked to original sources
PubMed1997

Rapid identification by specific PCR of coagulase-negative staphylococcal species important in hospital infection.

Polymerase chain reaction (PCR) identification assays were designed for eight major species of coagulase-negative staphylococci (CNS) on the basis of three variable regions found in the 16S rRNA gene. The PCR assays were tested with 41 staphylococcal strains representing the diversity of staphylococci defined by classical biotyping schemes. Each PCR result was compared with species-specific polymorphism in and around the 16S rRNA gene (i.e., 16S ribotype) and the phenotypic identification of the strain in a miniaturised biochemical test gallery (bioMerieux ATB 32 Staph). Twenty-six of the 41 strains were identified by PCR as belonging to one of the eight species for which primers had been designed and none of the remaining strains was misidentified. For 22 of the 26 strains there was complete agreement between the PCR identification, 16S ribotype and ATB identification. For the remaining four strains there was agreement between PCR identification and 16S ribotype. Two National Collection of Type Culture strains were re-assigned to different species and 10 previously unassigned strains were formally speciated for the first time. These PCR assays are suitable for rapid and definitive speciation of CNS.

Bacterial Typing Techniques↗
PubMed1997

Comparison of oral bambuterol and terbutaline in elderly patients with chronic reversible airflow obstruction.

Bambuterol, a carbamate prodrug of terbutaline, is the first once-daily oral beta 2-agonist. The effect/side effect ratio of bambuterol oral solution was compared with terbutaline mixture in elderly patients with chronic reversible obstructive airways disease. The study was of a double-blind, crossover, randomized design and consisted of a 4-7-day run-in period followed by four consecutive treatment periods each of 2 weeks. The treatments were bambuterol solution 20 mg nocte (B20), 10 mg nocte (B10), terbutaline mixture 3 mg t.i.d., (T), and placebo solution (P). Patients measured daily peak expiratory flow rate (PEFR), asthma symptoms, use of inhaled beta 2-agonist, and tremor. Of 84 patients, 66 completed all periods. Mean age was 67 years (60-90), basal FEV1 1.49 L, and reversibility of FEV1 30%. Ninety-four percent of the patients used inhaled/oral steroids in constant dosage. All treatments were significantly more effective than placebo. B20 resulted in higher morning PEFR than T (306 +/- 2.9 L/min vs. 297 +/- 2.9 L/min), while B10 gave equivalent results to T. No differences were seen in the use of inhaled beta 2-agonist. Less shortness of breath was experienced during the night with B20 and during the day with B10 compared with placebo. Both B20 and T produced more tremor than B10 and P. In elderly patients with chronic reversible airways obstruction once-daily bambuterol (10-20 mg) has a better effect/side effect ratio than 3 mg terbutaline thrice daily.

Administration, Oral↗
PubMed1996

Regeneration of immature mammalian spinal cord after injury.

In this review we describe the growth of regenerating fibres through lesions in immature mammalian spinal cord. In newborn opossums and foetal rats, repair occurs rapidly and reliably without antibodies, implants or bridges of undamaged spinal cord. In the neonatal opossum one can compare recovery from lesions made to the CNS at various stages of development in the animal and in culture. As the CNS matures, the capacity for regeneration ceases abruptly. In particular, the extracellular matrix and molecules associated with glia have been shown to play a role in promoting and inhibiting regeneration. Major problems concern the precision with which regenerating axons become reconnected to their targets, and the specificity needed for recovery of function.

Animals↗
PubMed1996

Interferon-gamma as a regulator of squamous differentiation.

Interferon-gamma (IFN-gamma) is a potent immunomodulatory molecule. Recent studies demonstrate that IFN-gamma can induce growth arrest and differentiation in epithelial cells. The signalling pathways controlling growth and differentiation in epithelial cells appears to be different to those regulating immune functions in non-epithelial cells and appear to impact on key cell cycle regulatory genes such as cdk1 and E2F1. In addition, studies with IFN-gamma have highlighted the complexity of the signalling pathways regulating the expression of differentiation markers in squamous differentiating epithelia. Given the actions of IFN-gamma upon epithelial cell growth and differentiation it should be considered a potential regulator of both immune and epithelial cell targets in various inflammatory pathologies such as psoriasis.

Adjuvants, Immunologic↗
PubMed1996

DNA insertion sequences and the molecular epidemiology of Salmonella and Mycobacterium.

The general characteristics and genetics of insertion sequence (IS) elements are well-established. For Escherichia coli IS elements, mechanisms of transposition and mutation are known and their recombinogenic role in the bacterial genome has been investigated. Population models relate the distribution of these IS elements to autoregulation of their transposition. IS200, the smallest known element, is confined to the salmonellae and several lineages of E. coli. It exhibits atypical molecular features. The population dynamics of IS200 make it a particularly effective marker of chromosomal genotype in many Salmonella serovars. Molecular epidemiological typing with IS200 has been developed for important serovars in groups D1, C1, C2 and B. Findings for S. Enteritidis, S. Panama, S. Infantis, S. Typhimurium, S. Heidelberg, S. Paratyphi B and S. Java are reviewed. Of the 12 IS elements found in mycobacteria, IS6110, found in Mycobacterium tuberculosis and M. bovis, exhibits the greatest potential for molecular epidemiological applications. Although M. tuberculosis is a single serogroup, and its genome is otherwise highly homogeneous, strains are highly polymorphic with respect to copy number and location of IS6110. A standard IS6110 typing method has been established, together with novel PCR-based approaches to IS6110 fingerprinting.

Animals↗
PubMed1995

Helicobacter pylori, gastroduodenal disease, and recurrent abdominal pain in children.

OBJECTIVE: To assess the evidence for a cause-and-effect relationship between Helicobacter pylori infection and antral gastritis, peptic ulcer disease, and recurrent abdominal pain in children. DATA SOURCES: A MEDLINE search from January 1983 through July 1994 was used to identify pertinent English-language publications. Current Contents and selected specialty journals were searched manually. Editorials, reviews, case reports, abstracts, and letters to the editor were excluded. STUDY SELECTION: All studies in children (ie, 0 to 18 years) were included. DATA EXTRACTION: Hill's criteria for causal inference were used to determine the strength of the evidence for a causal relationship. DATA SYNTHESIS: In total, 45 studies (case series, cross-sectional surveys, and treatment trials) were retrieved. The rate ratio of antral gastritis in children with H pylori infection (compared with uninfected children) ranged from 1.9 to 71.0 (median, 4.6). The prevalence of H pylori infection in children with duodenal ulcer was high (range, 33% to 100%; median, 92%) compared with children with gastric ulcer (range, 11% to 75%; median, 25%). Prevalence rates of infection in children with recurrent abdominal pain were inconsistent (range, 0% to 81%; median, 22%), with lower rates in children meeting Apley's criteria (range, 0% to 9%; median, 6%). CONCLUSIONS: There is strong evidence for an association between H pylori infection and antral gastritis and duodenal ulcer disease in children; however, data from randomized, double-blind, placebo-controlled treatment trials are required. There is weak evidence for an association with gastric ulcer and weak or no evidence for an association with recurrent abdominal pain.

Abdominal Pain↗
PubMed1995

The spectrum of hepatitis C antibody positive disease in a teaching hospital.

OBJECTIVE: To survey clinical associations of a positive hepatitis C virus antibody (HCV-antibody) test. DESIGN: Retrospective analysis of all positive HCV-antibody tests reported by a Virology Department. SETTING: A complex secondary and tertiary care teaching hospital. PATIENTS: 144 confirmed cases with HCV-antibody in serum, identified from approximately 2,500 clinical specimens tested. RESULTS: Over 99% of positive tests were in the following groups: liver dysfunction; multiply transfused individuals; intravenous drug abusers; patients with bleeding disorders; and renal replacement therapy. Amongst the patients with liver disease--the only group in which a known epidemiological association was not the indication for testing--over 25% of patients had no risk factor identifiable, representing 7.5% of the total group of HCV-antibody positive patients. CONCLUSION: Selective HCV-antibody testing in a U.K. hospital population reveals a substantial population of positive patients, and risk factors for hepatitis C are not always present.

Adolescent↗
PubMed1994

A model system for the study of antigen secretion by adult Schistosoma mansoni in vivo.

Schistosoma mansoni (6 weeks old) were surgically transferred from donor C57BI/6 mice to the hepatic portal veins of naive recipients of the same inbred strain. Between 70% and 100% of the parasites were alive 15 days later, and egg deposition was observed after transfer of worm pairs. The physiological status of the parasites was monitored by measuring the levels of a schistosome gut antigen, circulating anodic antigen (CAA), in the serum of the recipients. When only male worms were transferred, serum CAA levels increased slowly to a peak 9 days later, which was followed by a rapid decline. When worm pairs were transferred, there was an early peak in serum CAA levels followed by a gradual decline, but these levels were always higher than those recorded after male-only transfer; in two mice the pattern was similar to that observed following receipt of male worms. More CAA and eggs were produced after transfer of paired versus separated worms. It was concluded that although worm pairs can be successfully transferred, their physiological status may be sub-optimal. In contrast, male worms survive consistently well, and their transfer to a naive recipient provides a convenient model with which to study the release of antigens by schistosomes in vivo.

Animals↗
PubMed1994

Effects of antiplatelet therapy with indobufen or aspirin-dipyridamole on graft patency one year after coronary artery bypass grafting.

Saphenous vein coronary artery bypass graft patency can be increased by antiplatelet therapy. Aspirin plus dipyridamole are effective but are associated with tolerability problems. Indobufen is a possible alternative antiplatelet agent that may be better tolerated. A prospective, randomized, double-blind, parallel-group study was undertaken to compare the efficacy and safety of indobufen 200 mg twice daily with aspirin 300 mg thrice daily plus dipyridamole 75 mg thrice daily in preventing occlusion of autologous saphenous vein coronary artery bypass grafts. A total of 803 patients were randomized in the study, of whom 552 had a follow-up coronary angiogram approximately 1 year after operation. All anastomoses were patent in 56% of indobufen-treated patients and 59% of aspirin-dipyridamole recipients (p = 0.384). The percentage of all anastomoses patent was 82% in the indobufen group and 83% in the aspirin-dipyridamole group (p = 0.297). Mean postoperative blood loss was significantly less in the indobufen group (p = 0.043). Patients who received indobufen also had significantly fewer adverse events considered to be treatment-related compared with aspirin-dipyridamole recipients (p = 0.02). At the doses tested indobufen was as effective as aspirin plus dipyridamole in preventing occlusion of saphenous vein grafts and was better tolerated. Because indobufen was associated with less postoperative blood loss it may be used before operation in coronary artery bypass grafting.

Adolescent↗
PubMed1992

Sleep disordered breathing and cognitive function in a retirement village population.

Sleep disordered breathing (SDB) may be associated with cognitive dysfunction in non-demented elderly people. A random sample of 96 retirement village residents were given both neuropsychological assessment and overnight sleep monitoring with a portable microprocessor based system (Vitalog PMS-8). Respiratory disturbance index (RDI) was calculated as the number of apnoeas and hypopnoeas per hour of sleep. RDI was not associated with 'memory', 'verbal', and 'motor' factors identified from the analysis of cognitive tests, but was associated with the 'cerebral efficiency' factor (R2 = 0.21, p less than 0.0001). Seventy-three subjects had repeat neuropsychological tests, median time to follow-up being 17 months. Baseline RDI did not predict changes in scores on the two factors identified from the second analysis. We conclude that mild to moderate disturbance of breathing during sleep is not associated with cognitive dysfunction in non-demented subjects.

Activities of Daily Living↗
PubMed1992

The prognostic value of fetal ultrasonography before induction of labour.

OBJECTIVE: To investigate whether ultrasound examination of the fetus and amniotic fluid before induction of labour can provide useful prognostic information about the course of labour and mode of delivery. DESIGN: A prospective observational study. SETTING: The delivery suite of St Mary's Hospital, London. SUBJECTS: 101 women undergoing induction of labour. MEASURED VARIABLES: Biparietal diameter, head circumference, abdominal circumference, occipital position, amniotic fluid volume and umbilical artery Doppler velocimetry waveforms. MAIN OUTCOME MEASURES: The outcome of labour was assessed in terms of the induction delivery interval, the mode of delivery and the incidence of abnormal cardiotocograms in labour. RESULTS: Seven women were delivered by emergency caesarean section early in the first stage of labour because of a significant abnormality of the fetal heart trace and these pregnancies were characterized by small fetal abdominal circumference measurements. Marked oligohydramnios was also noted in five of these seven subjects. Small or average size babies who were surrounded by an adequate volume of amniotic fluid tended to be born spontaneously, whereas the majority of operative deliveries for failure to progress in labour were associated with fetal abdominal circumference measurements > or = 340 mm. The mean Bishop score of women before labour who delivered spontaneously was not significantly different from the scores of women who had a forceps delivery or caesarean section. Abnormal cord Doppler waveforms were observed in only one instance. CONCLUSIONS: In women undergoing induction of labour, the measurement by ultrasonography of two variables (fetal abdominal circumference and amniotic fluid volume) may allow the prospective identification of pregnancies at increased risk of fetal distress or dystocia. If these findings can be replicated in early spontaneous labour than more rational utilization of resources may be possible in hospital based obstetric practice.

Amniotic Fluid↗
PubMed1991

Can we abandon Naegele's rule?

A pregnant woman may become anxious if she has not delivered by the date given to her by her physician. Much anxiety would be alleviated if a range of dates (38-42 weeks) was substituted for a specific date of delivery.

Anxiety↗