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Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 163 records · Page 9Linked to original sources
PubMed1993

Evaluation of enzyme immunoassay performance characteristics--phencyclidine example.

Four reagent formulations (three provided by a manufacturer; one prepared in-house by mixing equal volumes of two commercial reagents) are used for the assay of phencyclidine (PCP) in urine samples. Performance characteristics evaluated included assay precision and sensitivity at and near the assay cutoff concentration. Data resulting from the reagent prepared in-house are better than those using then commercially available formulations, and are comparable with those obtained using the recently available new commercial formulation.

Enzyme Multiplied Immunoassay Technique↗
PubMed1992

Nitrosating activity in Escherichia coli.

Nitrosation activity was measured in Escherichia coli isolates and a range of nitrite reductase (nir) mutants. Activity was only detected in intact cells and could be inhibited by a number of treatments such as sonication and osmotic shock. Aerobically-grown cells had highest nitrosation activity compared to oxygen-limited ones. Inclusion of nitrite in growth media induced high activities of nitrite reductase and for some isolates, nitrosation. Analysis of nir mutants identified two which were unable to nitrosate. This result suggested that NADH-dependent nitrite reductase was implicated either directly or indirectly in nitrosation.

Aerobiosis↗
PubMed1992

Pharmacy beyond the dispensary: general practitioners' views.

OBJECTIVES: To ascertain general practitioners' attitudes to an extended role for community pharmacists. DESIGN: Postal questionnaire to a 1 in 6 sample of general practitioners in the Northern, West Midlands, and Oxford regions (total sample size 1087). MAIN OUTCOME MEASURES: Attitudes towards specific extended roles, pharmacist prescribing of particular drugs, the role of the pharmacist, and the relationship between the professions. RESULTS: 744 questionnaires were returned in a usable form, an overall response rate of 68.4%. Attitudes varied, from a majority in favour of pharmacists reporting adverse drug reactions to a majority against their supervising repeat prescriptions (81% and 36% in agreement respectively). A similar range of attitudes was shown to pharmacist prescribing, from 84% in agreement with their prescribing nicotine chewing gum (deregulated since the survey) to 11% agreeing to their prescribing cimetidine. About half the respondents thought general practitioners should be allowed to dispense and a third that pharmacists "should stick to dispensing." 27% agreed that pharmacists were too influenced by commercial pressures to give unbiased advice. CONCLUSIONS: Most doctors would favour an extension of the activities of community pharmacists but worry about their role in screening and counselling patients and in prescribing. Despite relationships being generally felt to be good, there may be a need for better communication and cooperation locally and for proper evaluation of initiatives to extend the role of the pharmacist.

Attitude of Health Personnel↗
PubMed1992

Rapid assessment of bacterial viability by flow cytometry.

The ability of a flow cytometer to rapidly assess microbial viability was investigated using three vital stains: rhodamine 123 (Rh123); 3,3'-dihexyloxacarbocyanine iodide [DiOC6(3)] and fluorescein diacetate (FDA). Rh123 was found to clearly differentiate viable from non-viable bacteria. The methodology for staining bacteria with this dye was optimised. Rh123 was shown to stain and discriminate several different species of viable bacteria although this was not universal. Viable cells of Bacillus subtilis were found to stain better with FDA than with Rh123. The results demonstrate the ability of flow cytometry to rapidly detect and estimate the viability of bacterial populations.

Bacterial Physiological Phenomena↗
PubMed1992

Effects of osmotic stress on mast cell vesicles of the beige mouse.

The large size of the vesicles of beige mouse peritoneal mast cells (4 microns in diameter) facilitated the direct observation of the individual osmotic behavior of vesicles. The vesicle diameter increased as much as 73% when intact cells were perfused with a 10 mM pH buffer solution; the swelling of the vesicle membranes exceeded that of the insoluble vesicle gel matrix, which resulted in the formation of a clear space between the optically dense gel matrix and the vesicle membrane. Hypertonic solutions shrank intact vesicles of lysed cells in a nonideal manner, suggesting a limit to the compressibility of the gel matrix. The nonideality at high osmotic strengths can be adequately explained as the consequence of an excluded volume and/or a three-dimensional gel-matrix spring. The observed osmotic activity of the vesicles implies that the great majority of the histamine known to be present is reversibly bound to the gel matrix. This binding allows vesicles to store a large quantity of transmitter without doing osmotic work. The large size of the vesicles also facilitated the measurement of the kinetics of release as a collection of individual fusion events. Capacitance measurements in beige mast cells revealed little difference in the kinetics of release in hypotonic, isotonic, and hypertonic solutions, thus eliminating certain classes of models based on the osmotic theory of exocytosis for mast cells.

Animals↗
PubMed1992

Identification of anatoxin-A in benthic cyanobacteria (blue-green algae) and in associated dog poisonings at Loch Insh, Scotland.

Dog deaths occurred in 1990 and 1991 after the animals drank water containing blooms of benthic cyanobacteria along the shoreline of Loch Insh, Scotland. Signs of poisoning in the affected animals and the high neurotoxicity of bloom extracts in laboratory bioassays indicated acute poisoning due to cyanobacterial neurotoxin(s). The neurotoxic blooms consisted largely of benthic Oscillatoria species which were also observed in the stomach contents of the poisoned dogs. Stomach contents were also neurotoxic in bioassays with the same signs of poisoning as the Oscillatoria blooms. The cyanobacterial alkaloid neurotoxin anatoxin-a was identified in bloom extracts and poisoned dog stomach contents by high-performance liquid chromatography and gas chromatography-mass spectrometry. A species of benthic Oscillatoria has been isolated from the neurotoxic bloom material and shown to produce anatoxin-a in laboratory culture. These findings are the first to associate anatoxin-a toxicoses with benthic, rather than planktonic, cyanobacteria. Procedures for anatoxin-a extraction and identification from the blooms and animal material are also detailed.

Animals↗
PubMed1992

Sumatriptan injection is superior to placebo in the acute treatment of migraine--with regard to both efficacy and general well-being.

The efficacy of subcutaneous injection of sumatriptan in the acute treatment of migraine was assessed in a double-blind, randomized, placebo-controlled cross-over study of 27 migraine patients. In addition, the patients were asked to give information about their well-being and subjective symptoms by means of a self-administered standardized questionnaire. A total of 22 migraine sufferers received a subcutaneous (sc) injection of 8 mg of sumatriptan and 24 received placebo. Of these patients, 19 received both treatments and thus completed the study. The primary efficacy end-point was a reduction in headache severity from severe or moderate to mild or no headache at 30, 60, 90 and 120 min. An effective response to treatment was achieved within 30 min in 63% and within 60 min in 84% of patients when treated with 8 mg sumatriptan sc, compared with 11% for placebo (p less than 0.001). Sumatriptan also provided significant relief from nausea and photophobia as compared with placebo. The proportion of patients that needed rescue medication after 120 min was significantly lower (p less than 0.001) with active treatment when compared with placebo. Sumatriptan was well tolerated and the majority of adverse events were mild and transient. The most frequent symptoms were those of malaise/fatigue or numbness. No changes in blood pressure or ECG readings were observed during the treatment. Compared with placebo, subcutaneous 8 mg sumatriptan also caused a substantial improvement in general well-being as revealed by the Minor Symptoms Evaluation Profile-acute (MSEP-acute) questionnaire.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

Sampling time for serum gentamicin levels.

A survey in 53 UK hospitals showed that 44% of clinical microbiologists recommended post-dose serum gentamicin concentrations to be measured at less than 40 min after an iv bolus dose. Serum gentamicin concentrations were measured in ten patients following bolus iv and im injections. Distribution of the drug occurred for up to 45 min following iv doses and maximum serum concentrations occurred at 45 to 60 min after im injection. The data validate current guidelines to sample at 60 min post bolus iv and im doses. Earlier sampling after iv bolus injections may result in significantly higher gentamicin concentrations, leading to potential interpretive errors of clinical significance.

Gentamicins↗
PubMed1992

The effect of pirenzepine on gastric emptying and salivary flow rate: constraints on the use of saliva paracetamol concentrations for the determination of paracetamol pharmacokinetics.

1. The effects of pirenzepine on gastric emptying, salivary flow and saliva paracetamol concentrations were investigated in healthy volunteers. 2. Pirenzepine significantly reduced the area under the saliva flow-time curves (7.29 +/- 3.30 g min-1 h without pirenzepine; 4.19 +/- 2.59 g min-1 h with pirenzepine, P less than 0.01). Pirenzepine had no significant effect on plasma paracetamol Cmax (17.5 +/- 7.8 micrograms ml-1 without pirenzepine; 12.6 +/- 7.7 micrograms ml-1 with pirenzepine), plasma tmax (0.2 h (0.2-0.8 h) without pirenzepine; (0.2 h 0.2-0.8 h) with pirenzepine) and plasma AUC(0.6 h) (32.3 +/- 7.2 micrograms ml-1 h without pirenzepine; 30.3 +/- 6.5 micrograms ml-1 h with pirenzepine). 3. Mean ratios of saliva:plasma paracetamol AUC (1.06 +/- 0.24 without pirenzepine; 1.84 +/- 0.48 with pirenzepine, P less than 0.001) and saliva:plasma paracetamol Cmax (1.7 +/- 1.0 without pirenzepine; 6.5 +/- 2.7 with pirenzepine, P less than 0.01) were significantly increased by pirenzepine pretreatment, but there was a poor correlation between the percentage change in the area under the saliva flow-time curve and the percentage change in saliva paracetamol AUC (r = 0.47, P = 0.21). 4. The findings suggest that a) pirenzepine is a more selective antagonist of the muscarinic receptors in salivary glands than those in gastric smooth muscle and b) caution is required when using saliva paracetamol concentrations to determine the pharmacokinetics of the drug in the presence of other agents which may influence salivary flow rate.

Acetaminophen↗
PubMed1992

The measurement of photodamage.

The use of non-invasive and invasive techniques for the assessment of human photodamaged skin is reviewed. Physical changes during photodamage and its treatment are best scored using a visual analogue scale rather than a short, non-equal interval scale. Epidermal thickness can be measured by histometric methods but dermal thickness can be measured non-invasively using pulsed A-scan and B-scan ultrasound techniques. These approaches are not effective in detecting any changes due to photodamage. Mechanical properties of the dermis can be determined using either a static or a dynamic test mode. The authors have used extensometry to provide a measure of the laxity of skin. Replicas of the crow's foot areas have been taken before and after tretinoin treatment, and the replicas have been inspected by optical profilometry. Reductions of blood flow in photodamaged skin have been established using laser Doppler measurements, the effect being reversed by topical tretinoin. Invasive biochemical techniques have the disadvantage that they generally require large amounts of tissue. Cytochemical techniques, however, have shown increased glucose-6-phosphate dehydrogenase activity in the granular cell layer of patients with non-melanoma skin cancer, premalignant epidermal lesions, sun-damaged epidermis and artificially irradiated skin. This technique may provide an important model for the study of photodamage. It is concluded that there is no single method available to quantify the degenerative changes associated with photodamage and the effects of tretinoin.

Adult↗
PubMed1992

Chronic transmural bronchiolitis: a non-specific lesion of small airways.

AIMS: To investigate nine patients with histological changes at open lung biopsy compatible with so-called "small airways disease"; to define these changes and distinguish them from other types of bronchiolitis; and to correlate them with clinical features, respiratory physiology, and other laboratory investigations. METHODS: The open biopsy sections and the clinical records were reviewed. RESULTS: There was chronic inflammation of the walls of centri-acinar respiratory bronchioles and peribronchiolar alveoli. Peripheral alveoli of affected acini were spared. Although lumens were narrowed and distorted, obstruction by granulation tissue plugs was not a feature. Clinical backgrounds included Hodgkin's disease, yellow nail syndrome, sicca syndrome, asthma and psoriasis. The main presenting symptoms were cough, dyspnoea and wheeze, often associated with basal crackles and basal shadowing. There was no consistent immunological or haematological abnormality. Sputum culture was negative in six patients, and a variety of organisms were cultured from three others. In most cases respiratory function tests revealed an irreversible obstructive defect (combined in some cases with a restrictive defect), gas trapping, and well preserved gas transfer. Lung volumes were normal. Bronchodilators, with steroids and azathioprine in more seriously affected patients, stabilised the disease process. CONCLUSIONS: The histological changes may be distinguished from bronchiolitis obliterans and bronchiolitis obliterans organising pneumonia by the absence of intraluminal granulation tissue plugs, and from the obliterative bronchiolitis of rheumatoid disease and diffuse peribronchiolitis on clinical grounds. Although often striking, this lesion does not represent a clinico-pathological entity, and may occur in the distal lung in association with a number of different diseases. "Small airways disease" is often used by clinicians in a functional context, and may lead to confusion. It is suggested that "chronic transmural bronchiolitis" is a more appropriate term.

Adult↗
PubMed1991

Twenty five years of case finding and audit in a socially deprived community.

OBJECTIVE: To evaluate audit and case finding (whole population care) in a community over 25 years. DESIGN: Contemporary screening for and audits of care of chronic disease and risk factors; retrospective review of computerised practice records; and comparisons of mortality and social indices with neighbouring communities. SETTING: One general practice in Glyncorrwg, West Glamorgan. SUBJECTS: 1800 people registered with the practice in 1987 and 558 people who died from 1964 to 1987, whose records had been retained. MAIN OUTCOME MEASURES: Detection of high blood pressure, smoking, airways obstruction, obesity, diabetes, and alcohol problems in adults aged 20-79; prevalence of smoking in this population and in hypertensive and diabetic groups; age standardised mortality ratios in relation to indices of social deprivation. RESULTS: In the population aged 20-79 (1207 patients) 249 (21%) had peak expiratory flow rate less than 50% of expected value or which improved by 15% or more with an inhaled beta agonist, 207 (17%) had body mass index at or over 30 kg/m2, 118 (10%) had untreated mean arterial pressures greater than 159/104 mm Hg (three readings), 80 (7%) (65 (16%) men, 15 (4%) women) had recognised alcohol problems, and 35 (3%) had diabetes. The proportion of men aged 20-64 who said they smoked fell from 61% (290/476) in 1968-70 to 36% (162/456) in 1985 whereas that of women who smoked was unchanged (43%, 187/436 v 42%, 190/448 respectively). In 116 screened hypertensive patients group mean blood pressure fell from 186/110 mm Hg before treatment to 146/84 mm Hg at 1987 audit, as did the proportion of smokers (56% v 20%), but body mass index and total cholesterol concentration showed no significant change. In 34 diabetic patients mean blood pressure and the proportion of smokers fell (171/93 mm Hg v 155/81 mm Hg; 44% v 12%). The age standardised mortality ratio in 1981-6 was lower than in a neighbouring village without a developed case finding programme (actual to expected deaths less than 65 = 21 to 22 in Glyncorrwg, 48 to 30 in control village). CONCLUSIONS: Whole population care through organised case finding and audit is feasible but only with a labour intensive approach combining accessibility, flexibility, and continuity, as well as a planned and structured approach, which requires substantial expansion of staff numbers and assiduous recording. It may reduce risks for at least some high risk groups. Despite their shortcomings the available data are consistent with the hypothesis that whole population care helps reduce mortality. Incentives in the new contract, which encourage the uncritical development of structured process, may diminish health outputs.

Adult↗