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Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 145 records · Page 8Linked to original sources
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↗
PubMed1993

Conversion of flosequinan to the sulphone metabolite in subcellular fractions of human liver, in-vitro.

Flosequinan was metabolized in a NADPH-dependent reaction, by S-oxidation to its principal metabolite, the sulphone. Most of the sulphone metabolite was formed within 20 min and reached a plateau by 60 min, following incubations of flosequinan (31, 61 or 122 microM) with the microsomal fraction. Flosequinan was metabolized mainly by the microsomal fraction. The S-oxidation of flosequinan in incubations containing mitochondrial and cytosolic fractions was 13 and 5%, respectively, of that detected in the microsomal fraction. The route of metabolism of flosequinan in-vitro correlates closely with that previously observed in-vivo. This model could be useful for studying the potential effects of other drugs on flosequinan metabolism in-vitro.

Adult↗
PubMed1993

Rapid, automated separation of specific bacteria from lake water and sewage by flow cytometry and cell sorting.

The use of fluorescence-activated flow cytometric cell sorting to obtain highly enriched populations of viable target bacteria was investigated. Preliminary studies employed mixtures of Staphylococcus aureus and Escherichia coli. Cells of S. aureus, when mixed in different proportions with E. coli, could be selectively recovered at a purity in excess of 90%. This was possible even when S. aureus composed only approximately 0.4% of the total cells. Cell sorting was also tested for the ability to recover E. coli from natural lake water populations and sewage. The environmental samples were challenged with fluorescently labelled antibodies specific for E. coli prior to cell sorting. Final sample purities of greater than 70% were routinely achieved, as determined by CFU. Populations of E. coli released into environmental samples were recovered at greater than 90% purity. The use of flow cytometry and cell sorting to detect and recover viable target bacteria present at levels of less than 1% within an indigenous microflora was also demonstrated.

Antibodies, Bacterial↗
PubMed1993

p53 expression in oat and non-oat small cell lung carcinomas: correlations with proliferating cell nuclear antigen.

AIMS: To investigate the immunohistochemical expression of p53 protein in small cell lung carcinoma (SCLC), comparing it with that in non-small cell carcinoma (NSCLC); and to evaluate the correlation between p53 and proliferating cell nuclear antigen (PCNA) expression as well as between p53 and PCNA expression and survival. METHODS: Paraffin wax embedded tissues from 61 cases of primary lung carcinoma were stained for p53 protein and PCNA using the monoclonal antibodies 1801 and PC-10, respectively, in a standard avidin-biotin immunoperoxidase method. RESULTS: Of the 61 lung carcinomas 35 (57%) were positive for p53 (range 1% to 90%). Ninety percent of the non-oat SCLC contained positive cells and the labelling index (LI) was significantly higher than that of the oat SCLC (p < 0.001). SLCC also displayed a higher p53 LI than NSCLC (p < 0.01); no difference was found between squamous carcinoma, adenocarcinoma, and oat cell carcinoma. A p53 LI of greater than 1% tended to be associated with nodal metastases (p < 0.05), and p53 expression in node positive tumours as well as in oat cell carcinomas was indicative of poorer survival (p < 0.01 and p < 0.1, respectively). A p53 Li of greater than 60% was a negative prognostic factor in non-oat SCLC (p < 0.05). PCNA LI was highest in non-oat SCLC and lowest in NSCLC; oat cell carcinomas had a mean LI intermediate between NSCLC and non-oat SCLC (NSCLC v oat cell carcinoma p < 0.05 and oat cell v non-oat cell carcinomas p < 0.01). A PCNA LI was not correlated with nodal metastases or survival, but there was a significant positive correlation between PCNA LI and p53 LI (rs = 0.484, p < 0.001). CONCLUSIONS: p53 and PCNA expression differ substantially among the various types of lung carcinomas. Substantial differences were also found between oat and non-oat types of SCLC, indicating that SCLC is heterogeneous as far as proliferation rate and altered p53 expression is concerned. p53 seems to be of some prognostic value. The relation between PCNA and p53 expression indicates that the PCNA gene is slightly upregulated by p53.

Antigens, Neoplasm↗
PubMed1993

Deaths and necropsies in a thoracic unit.

BACKGROUND: There is concern about the decrease in the number of requests for necropsies, so a study was undertaken to assess current clinical practice. METHOD: A prospective study was made of all deaths occurring under the care of five chest physicians and three thoracic surgeons at East Birmingham Hospital from 1 April to 30 June 1989. RESULTS: A necropsy was sought in 34 of 58 deaths (59%) and was performed in 22 instances (38%). Major unexpected findings which would have affected clinical management were noted in three patients (14%). The mean delay in reporting results of histological examinations was 146 days (range 41-260 days). As the result of an increase in pathology technical staff levels and alteration in the practice of processing histological data, there was a substantial improvement during the corresponding period in 1990 (mean reduction 58 days, 95% confidence limits 39-77 days). Apart from patients with histologically proved carcinoma, there was no consistent pattern for requests for necropsies. CONCLUSIONS: Necropsies continue to reveal diagnoses which were not suspected while the patient was alive. Although the number of requests made by clinical staff for necropsies is reasonable, the reasons for the requests are not consistent. Guidelines are suggested to improve the number of successful requests and to maximise the information obtained from them.

Autopsy↗
PubMed1993

The long-term prevention of tobacco use among junior high school students: classroom and telephone interventions.

OBJECTIVES: The purpose of this study was to implement and evaluate the effectiveness of a long-term tobacco use prevention program for junior high school students that used college undergraduate change agents and telephone boosters. METHODS: A psychosocial intervention combining refusal skills training, contingency management, and other tobacco use prevention methodologies such as telephone and mail boosters was implemented in 11 junior high schools in San Diego County, California. Eleven other junior high schools served as controls. Of the 2668 participants, 57% were White/non-Hispanic, 24% were Hispanic, and 19% were of other racial/ethnic groups. College undergraduates served as change agents for both the classroom and booster interventions, the latter of which was delivered in the third (ninth-grade) year of the program. RESULTS: At the end of the third year, the prevalence of tobacco use within the past month was 14.2% among the intervention students and 22.5% among the controls, yielding an odds ratio of 0.71 for analysis at the school level. CONCLUSIONS: Both college undergraduate change agents and direct one-to-one telephone interventions appear to provide cost-effective tobacco-related behavior modification.

Adolescent↗