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Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 127 records · Page 7Linked to original sources
PubMed1994

Survival of Staphylococcus aureus in lakewater monitored by flow cytometry.

The ability of flow cytometry to detect and enumerate viable bacteria during survival in a lakewater microcosm was assessed using Staphylococcus aureus as a model organism. Counts of colony-forming units (c.f.u.) on nutrient agar were not significantly different from those obtained by flow cytometric detection of rhodamine 123 stained bacteria and there was no evidence for a viable but nonculturable state using these methods. However c.f.u. were significantly lower when estimated using mannitol salts agar compared with nutrient agar. S. aureus was also enumerated immunofluorescently after staining with FITC-IgG. There was no significant difference between the population estimated immunofluorescently and by acridine orange direct counting, and unlike estimations of viability, only slight reductions in total cell numbers were observed. Changes in the protein and nucleic acid content of S. aureus during survival were also measured by flow cytometry to investigate any potential heterogeneity arising within the starved population. Flow cytometric determinations were found to correlate significantly with their respective chemical determinations. These results demonstrate the ability of flow cytometry to detect viable bacteria during starvation and to study changes in macromolecular content. They also illustrate the importance of using appropriate methods for the detection of viable bacteria in environmental samples.

Bacterial Proteins↗
PubMed1994

Continuous culture studies on the synthesis of capsular polysaccharide by Klebsiella pneumoniae K1.

The synthesis of capsular polysaccharide by Klebsiella pneumoniae K1 was investigated in a minimal salts medium by continuous culture. The organism produced larger amounts of polysaccharide under nitrogen-limited conditions than under carbon-limited conditions. The synthesis of polysaccharide was dependent not only on the availability of excess carbon, but also on growth rate. The rate of polysaccharide synthesis was greatest at low dilutions, low temperature (30 degrees C) and at neutral pH. Prolonged growth in nitrogen-limited culture resulted in the development of non-mucoid variants, possibly due to a selective growth advantage over mucoid cells. The non-mucoid isolate was more susceptible to some bacteriophages, possibly due to the reduction nor absence of capsular polysaccharide.

Bacteriological Techniques↗
PubMed1994

Protease production by Streptomyces thermovulgaris grown on rapemeal-derived media.

A range of actinomycete species was tested for their ability to grow on particulate and particle-free rapeseed meal-derived media. Streptomycetes grew on both types of medium and produced a number of extracellular enzymes. Highest activities of protease were produced by Streptomyces thermovulgaris and reflected the high available protein content of rapemeal. Enzyme production and growth were analysed in fermentor-grown batch cultures of S. thermovulgaris using the particle-free rapemeal broth termed medium B. Growth was biphasic and the majority of the protease was produced during the second slower phase. Analysis of the protease as azocaseinase activity revealed a high degree of thermostability in the presence of calcium such that approximately 20% of the activity remained after incubation at 70 degrees C for 24 h. Gel filtration suggested that S. thermovulgaris synthesized more than one kind of protease and this was confirmed by using specific peptide substrates and inhibitors which revealed the presence of distinct serine and metallo-type enzymes.

Brassica↗
PubMed1994

The influence of ciprofloxacin on the pharmacokinetics and pharmacodynamics of a single dose of temazepam in the young and elderly.

The effect of pretreatment with a 4-day course of ciprofloxacin (500 mg twice daily) on the pharmacokinetics and pharmacodynamics of a single oral dose of temazepam (10 mg) was investigated in 12 healthy young and nine elderly patient volunteers in a crossover design study. Temazepam clearance was lower in the elderly than in the young, but this difference was not statistically significant. Ciprofloxacin had no significant effect on temazepam pharmacokinetics or pharmacodynamics in either age group.

Administration, Oral↗
PubMed1994

Seasonal variation in the necropsy incidence of massive pulmonary embolism.

AIMS: To investigate the seasonal incidence of massive pulmonary embolism at necropsy. METHODS: Massive pulmonary embolism was defined as a recent thromboembolus occluding the pulmonary trunk or one or both main pulmonary arteries and constituting the main cause of death. A total of 4289 necropsies carried out at East Birmingham Hospital from 1979 to 1988 was reviewed. The number of subjects with massive pulmonary embolism was noted and the accumulated percentage for each calendar month was calculated. RESULTS: Massive pulmonary embolism was found in 13.02% of necropsies carried out in April; in September and October the percentage rose to 14.29 and 14.19, respectively, after falling to 8.04 and 7.80 in June and July. In January and February the incidence fell again to about 9%. CONCLUSIONS: The incidence of massive pulmonary embolism at East Birmingham Hospital is highest in the spring and autumn. Investigation of the seasonal incidence in arctic and tropical areas would be of interest.

Autopsy↗
PubMed1994

Diagnosing and managing unstable angina. Agency for Health Care Policy and Research.

This Quick Reference Guide for Clinicians contains recommendations on the care of patients with unstable angina based on a combination of evidence obtained through extensive literature reviews and consensus among members of an expert panel. Principal conclusions include the following. (1) Many patients suspected of having unstable angina can be discharged home after adequate initial evaluation. (2) Further outpatient evaluation may be scheduled for up to 72 hours after initial presentation for patients with clinical symptoms of unstable angina judged at initial evaluation to be at low risk for complications. (3) Patients with acute ischemic heart disease judged to be at intermediate or high risk of complications should be hospitalized for careful monitoring of their clinical course. (4) Intravenous thrombolytic therapy should not be administered to patients without evidence of ST segment elevation and acute myocardial infarction. (5) Assessment of prognosis by noninvasive testing often aids selection of appropriate therapy. (6) Coronary angiography is appropriate for patients judged to be at high risk for cardiac complications or death based on their clinical course or results of noninvasive testing. (7) Coronary artery bypass surgery should be recommended for almost all patients with left main disease and many patients with three-vessel disease, especially those with left ventricular dysfunction. (8) The discharge care plan should include continued monitoring of symptoms; appropriate drug therapy, including aspirin; risk-factor modification; and counseling.

Ambulatory Care↗
PubMed1994

Improved gas chromatography/mass spectrometry analysis of barbiturates in urine using centrifuge-based solid-phase extraction, methylation, with d5-pentobarbital as internal standard.

Effective solid-phase extraction, derivatization, and GC/MS procedures are developed for the simultaneous determinations of butalbital, amobarbital, pentobarbital, and secobarbital, using a deuterated pentobarbital (d5-pentobarbital) as the internal standard. Buffered (pH 7) urine samples were extracted with Bond Elute Certify II cartridge. Iodomethane/tetramethylammonium hydroxide in dimethylsulfoxide was used for methylation, while a HP 5970 MSD equipped with a 13 m J & W DB-5 column (5% phenyl polysiloxane phase) and the Thru-Put Target software package were used for GC/MS analysis and data processing. This protocol was found to be superior, in both chromatographic performance characteristics and quantitation results, over a liquid-liquid extraction procedure without derivatization using hexobarbital as the internal standard. Extraction recoveries observed from control samples containing four barbiturates range from 80% to 90%. Good one-point calibration data are obtained for all four barbiturates in the 50 to 3200 ng/mL range. Interestingly, the one-point calibration data for pentobarbital are inferior to the other three barbiturates--due to interference from the internal standard (d5-pentobarbital). The calibration data of pentobarbital are best described by a hyperbolic curve regression model. Precision data (% CV) for GC/MS analysis, over-all procedure, and day-to-day performance are approximately 2.0%, 6.0%, and 8.0%, respectively. With the use of a 2 mL sample size, the attainable detection limit is approximately 20 ng/mL.

Amobarbital↗
PubMed1994

Hypertension in pregnancy.

Hypertension, which is the most common complication of pregnancy, is a leading cause of both maternal and perinatal morbidity. Advances in research related to hypertensive disorders in pregnancy have facilitated a better general understanding of the pathophysiologic processes associated with this disease. Strategies of prevention, early diagnosis, and newer treatments have contributed to a more favorable outcome for mothers and their babies. The exact cause of preeclampsia remains elusive; however, recent investigations suggest that endothelial cell injury due to free radical-mediated lipid peroxidation may be the initiator of the pathophysiologic events of preeclampsia. Future challenges in this area should include efforts to elucidate mechanisms involved in free radical cell-mediated vascular disturbances and antioxidant defenses.

Chronic Disease↗
PubMed1993

Comparison of prescribing unit with index including both age and sex in assessing general practice prescribing costs.

OBJECTIVE: To examine and compare the prescribing unit and a new prescribing index adjusting for age and sex in assessing general practice prescribing. DESIGN: Analysis of all prescriptions issued by two practices in one year. Use of data to derive a prescribing index adjusting for age and sex. Comparison of effect of prescribing unit and new index on relation between 80 practices' prescribing data and family health services authority average. SETTING: Newcastle and Gateshead Family Health Services Authorities. Two urban practices with eight doctors and combined list size of 16,300 patients. MAIN OUTCOME MEASURES: Cost and number of prescriptions issued to each age and sex group. Effect of index on relation between practice data and family health services authority average. RESULTS: The number of items prescribed and total costs rose with age. Although total costs were greater for women than for men, individual items cost more for men aged 25-84. Comparison of data adjusted by the prescribing unit and the new index with authority averages produced no significant differences except in a few practices with skewed age-sex demography. Results with the two indexes differed by over 5% in 34% (27/80) of practices for costs and in 14% (11/80) for items prescribed. CONCLUSIONS: The age and sex profile of a practice does not explain interpractice variation in prescribing patterns. Other unidentified factors need to be considered.

Adolescent↗
PubMed1993

Screen detected high blood pressure under 40: a general practice population followed up for 21 years.

OBJECTIVE: To assess hypertension detected under 40 in a general practice population. DESIGN: Prospective case-control study. SETTING AND SUBJECTS: Former coal mining community in south Wales. Systematic case finding for hypertension and associated risk factors applied to a mean total population of 1945 from age 20 on a five year cycle through 21 years. Mean population aged 20-39, 227 men and 213 women. Case criteria: age < 40 and mean systolic pressure > or = 160 mm Hg or diastolic pressure > or = 100 mm Hg. Age and sex matched controls randomly sampled from the same population. MAIN OUTCOME MEASURES: Mean initial pressures and pressures at follow up in 1989 or preceding death, and all cardiovascular events. RESULTS: 25 men and 16 women met criteria. Estimated five yearly inceptions were 26/1000 for men and 18/1000 for women. Male group mean initial blood pressure was 164/110 mm Hg for cases, falling to 148/89 mm Hg at follow up. Five male cases died at mean age 47.8, compared with two controls at 49.5. Female group mean initial pressure was 172/107 mm Hg for cases, falling to 145/86 mm Hg at follow up. One female case died aged 50, no controls. 10 male cases had non-fatal cardiovascular events at mean age 40.2, compared with two controls at mean age 50.5. Four female cases had non-fatal events at mean age 47.2, compared with one control aged 58. Male differences were statistically significant. CONCLUSIONS: Hypertension under 40 is dangerous, commoner in men than women, rarely secondary to classic causes, and may be controlled in general practice on a whole community basis.

Adult↗
PubMed1993

The influence of steady-state ciprofloxacin on the pharmacokinetics and pharmacodynamics of a single dose of diazepam in healthy volunteers.

The effects of pretreatment with a seven day course of ciprofloxacin on pharmacokinetics and pharmacodynamics of an intravenous (5 mg) dose of diazepam were investigated in a group of 12 healthy volunteers in a double-blind placebo-controlled crossover study. Ciprofloxacin pretreatment significantly reduced diazepam CL (without ciprofloxacin: 19.5 ml.h-1 kg-1; with ciprofloxacin: 12.3 ml.h-1 kg-1). Diazepam t1/2 was also prolonged (without ciprofloxacin: 36.7 h; with ciprofloxacin: 71.1 h), but volume of distribution was unaltered (without ciprofloxacin: 1.1 l.kg-1; with ciprofloxacin: 1.1 l.kg-1). However, no significant changes were detected in psychometric tests of digit symbol substitution, tapping rate and short memory, as well as levels of concentration, vigilance and tension measured by visual analogue scales.

Adult↗
PubMed1993

A model of measured percussive mechanical trauma and its effects on skin.

In this study, the role of mechanical trauma to skin in industrial dermatitis is considered. The percussive component of mechanical trauma to skin is investigated by modelling it, using an oscillating device which can supply a range of percussive trauma doses. The instrument is electronically controlled, and contains sensors which monitor the force and displacement throughout each impact. From this information, a value proportional to the dose delivered to the skin is calculated and used, rather than the driving power of the percussor. The rate of dose is also controlled. In this study, doses were delivered at a frequency of 7 Hz. Eight volunteers were given regimens of percussive trauma at regular intervals over a 5-day period. Half the group received a dose of 4 mJ/cm2 per impact, the other half received double this dose. The skin response was evaluated using non-invasive measurements of transepidermal water loss, skin thickness, and erythema. The results demonstrate that erythema, skin thickness and transepidermal water loss are all increased after mechanical challenge--erythema and water loss by amounts dependent upon the trauma dose applied. The transepidermal water loss results indicate that for the subjects used in our study, there was a trauma threshold reached after a cumulative dose of greater than 250 J/cm2.

Dermatitis, Occupational↗