Search PubMed⌕ Search

Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 163 records · Page 9Linked to original sources
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↗
PubMed1991

Oscillating activity of a calcium-activated K+ channel in normal and cancerous mammary cells in culture.

Calcium-activated potassium channels were the channels most frequently observed in primary cultured normal mammary cell and in the established mammary tumor cell, MMT060562. In both cells, single-channel and whole-cell clamp recordings sometimes showed slow oscillations of the Ca2(+)-gated K+ current. The characteristics of the Ca2(+)-activated K+ channels in normal and cancerous mammary cells were quite similar. The slope conductances changed from 8 to 70 pS depending on the mode of recording and the ionic composition in the patch electrode. The open probability of this channel increased between 0.1 to 1 microM of the intracellular Ca2+, but it was independent of the membrane potential. Charybdotoxin reduced the activity of the Ca2(+)-activated K+ channel and the oscillation of the membrane current, but apamin had no apparent effect. The application of tetraethylammonium (TEA) from outside and BaCl2 from inside of the cell diminished the activity of the channel. The properties of this channel were different from those of both the large conductance (BK or MAXI K) and small conductance (SK) type Ca2(+)-activated K+ channels.

Animals↗
PubMed1991

Correlation of donor nutritional status with sinusoidal lining cell viability and liver function in the rat.

We have demonstrated that the sinusoidal lining cell injury sustained by rat liver allografts during hypothermic storage is a critical determinant of graft viability. The present study was designed to examine the effect of donor nutritional status on hepatic microcirculation and graft function. Rat livers from four nutritional groups (group I, fasted; group II, fed; group III, intraperitoneal glucose; and group IV, fed plus intraperitoneal glucose) were excised and stored for 24 hr in Marshall's isotonic citrate solution. Then the livers were perfused under anoxic conditions with trypan blue. The percentage of nonviable SLC in each group was 26.7 +/- 8.1, 24.9 +/- 7.9, 17.6 +/- 6.9, and 5.9 +/- 1.9 in groups I, II, III, and IV respectively; i.e., there was a significant improvement in SLC viability with nutritional repletion in group IV. Electron microscopy was performed on livers from groups I and IV following 30-hr preservation in University of Wisconsin solution and after 16-hr preservation in Marshall's isotonic citrate solution. Biopsies were taken at the end of storage and after 1 hr of reperfusion at 37 degrees C. At the end of preservation group IV livers contained glycogen and had much more normal liver ultrastructure than group I livers. After reperfusion there was partial recovery of normal SLC morphology in both groups and depletion of glycogen in group IV. Liver function was studied on the isolated perfused rat liver system at 37 degrees C following 30-hr storage in UW solution. Transaminase release into the perfusate was significantly lower in nutritionally repleted livers than in livers from fasted animals. A significant reduction in perfusate platelet count occurred only in livers from fasted animals. The results show that nutritional repletion can reduce the injury of cold preservation to both hepatocytes and endothelial cells and improve liver function in the postpreservation period.

Alanine Transaminase↗
PubMed1991

The effects of temperature, pH and growth rate on secondary metabolism in Streptomyces thermoviolaceus grown in a chemostat.

Streptomyces thermoviolaceus was grown in a chemostat under conditions of glutamate limitation. The effects of growth rate on production of the antibiotic granaticin, extracellular protein and protease activity as components of secondary metabolism were studied at 37, 45 and 50 degrees C. The amount of each secondary metabolite synthesized was highly dependent on growth rate and temperature. Granaticin yields were highest at growth rates of 0.1 to 0.15 h-1 at 37 degrees C, 0.175 h-1 at 45 degrees C and 0.045 h-1 at 50 degrees C. Protease activity of culture supernatants responded to low nutrient concentration and/or low growth rate. Measurements of extracellular protein revealed complex changes in amount which were dependent on growth rate and temperature. At 45 degrees C and a growth rate of 0.15 h-1, biomass yield was highest between pH 5.5 to 6.5 whereas granaticin synthesis was low at pH 5.5 and rose to highest values at between pH 6.5 and 7.5.

Antibiotics, Antineoplastic↗
PubMed1991

Survival of a plasmid-bearing strain of Bacillus subtilis introduced into compost.

Survival of Bacillus subtilis strain 168 containing plasmid pAB224, which carries a gene for tetracycline resistance, was studied in mushroom compost under mesophilic and thermophilic conditions. Stable populations of B. subtilis were maintained as spores in both sterile and fresh mushroom compost incubated at 37 degrees C. At 65 degrees C, the introduced B. subtilis populations declined during incubation but spores were still detectable after 28 d. Survival at the higher temperature was greater in fresh than in sterile compost. There was no apparent loss of plasmid pAB224 or plasmid-determined phenotype from the introduced B. subtilis population at either incubation temperature. The frequency of tetracycline resistance in the indigenous Bacillus population was very low (10(-5), but some tetracycline-resistant isolates contained plasmid DNA. Four plasmid DNA profiles were found associated with five Bacillus phenotypes, and some evidence for homology with pAB224 was found. However, pAB224 was found to be a suitable marker for release studies because it was easily recovered, readily distinguished from indigenous plasmids on agarose gels, and was maintained in compost-grown B. subtilis 168 in the absence of any selective pressure.

Bacillus subtilis↗
PubMed1991

Hospital prescribing and usage of hypnotics and anxiolytics.

In-patient prescribing and usage of hypnotic and anxiolytic drugs were surveyed in a teaching hospital for 4 to 6 weeks. Twenty-one percent of admissions were prescribed these drugs which were predominantly benzodiazepines. Few patients (1.6%) were discharged with such prescriptions and subsequent usage in the community was similar to that before admission to hospital (6.1% and 6.4% respectively). In-patient consumption increased with patient age and both prescriptions and consumption were greater in women than men.

Anti-Anxiety Agents↗
PubMed1991

Lack of effect of flosequinan on the pharmacokinetics of theophylline.

The pharmacokinetics of theophylline (240 mg) p.o. were studied before and after the administration of oral flosequinan for 14 days in 21 healthy volunteers using a randomised cross-over design. Comparisons of Cmax, tmax, AUC, CL of theophylline and urinary recovery of the parent drug and metabolites showed that flosequinan had no significant effect on the disposition of theophylline.

Administration, Oral↗
PubMed1991

Haemophagocytic syndrome.

Two fatal cases of haemophagocytic syndrome diagnosed on the basis of autopsy findings at the Queen Elizabeth Hospital, Barbados, are presented. They were both young patients, a male 20 years of age and a female 28 years of age, with common clinical features of severe constitutional symptoms, pharyngeal haemorrhages, pancytopenia, and fever. The female patient had elevated titres to herpes simplex virus indicative of recent infection as well as postmortem evidence of overwhelming mixed bacteria sepsis. In both cases, histopathological studies showed lymphoid depletion and histiocytes displaying haemophagocytosis.

Adult↗
PubMed1991

Enzymatic digestion, solid-phase extraction, and gas chromatography/mass spectrometry of derivatized intact oxazepam in urine.

Enzymatic digestion with beta-glucuronidase (EC 3.2.1.31) was used to release intact oxazepam from urine samples containing the d5-analog internal standard. The resulting specimens were extracted with Du Pont PREP Type W cartridge (processed by a PREP Automated Sample Processor), Bond Elut Certify, and J.T. Baker "spe" columns for comparison of the columns' extraction recovery and overall effectiveness. Methyl iodide/tetrahexylammonium hydrogen sulfate and N,O-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (10 g/L) were used for the methylation and trimethylsilylation studies. We used a Hewlett-Packard HP 5790 mass-selective detector equipped with a 13-m J & W DB-5 column (5% phenyl polysiloxane phase) for gas chromatography/mass spectroscopy (GC/MS) analysis and the Thru-Put Target software package for data processing. After several exploratory experiments, we adopted the Du Pont PREP system methylation procedure because of its effective recovery, the superior stability of the derivatization product, the possibility of incorporating a clean-up step, and the potential for high throughput. The extraction recovery from a set of control samples was 87%. Coefficients of variation obtained for six replicates of GC/MS analysis and for the overall procedure were 1% and 3%, respectively. Excellent linearity was established in the 50-8000 micrograms/L concentration range studied. With the use of 3-mL samples, a 20-microL final reconstitution volume, oxazepam at 50 micrograms/L was easily detected under the adopted operation conditions.

Benzodiazepines↗