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Biomedical subjects

E Dickinson

Publications and source records attributed to E Dickinson.

69 records · Page 4Linked to original sources
PubMed1993

To AZT or not to AZT.

Explore the source record for details and available documents.

Emergency Medical Technicians↗
PubMed1991

Time-dependent polymerization of beta-lactoglobulin through disulphide bonds at the oil-water interface in emulsions.

Time-dependent intermolecular sulphydryl-disulphide interchange involving beta-lactoglobulin adsorbed at the oil-water interface in n-tetradecane-in-water emulsions (10 wt% oil, 0.5 wt% protein, pH 7.0) has been investigated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). While only monomers are detected in the adsorbed protein immediately after emulsion formation with pure beta-lactoglobulin, on storing the emulsion the amount of polymerized beta-lactoglobulin and the sizes of the oligomers are found to increase with time. There is no polymerization of adsorbed protein in emulsions made with pure alpha-lactalbumin after 72 h, or in emulsions made with beta-lactoglobulin in the presence of a reagent (N-ethylmaleimide) for modifying sulphydryl groups. Analysis by two-dimensional SDS-PAGE of adsorbed protein from aged emulsions made with a mixture of alpha-lactalbumin + beta-lactoglobulin shows some linking by disulphide bonds between alpha-lactalbumin and beta-lactoglobulin at the interface. Taken together with earlier time-dependent surface viscosity measurements, the results indicate the important role of free sulphydryl groups in the development of the high surface viscoelasticity of adsorbed globular proteins at the oil-water interface.

Adsorption↗
PubMed1990

Surface shear viscometry as a probe of protein-protein interactions in mixed milk protein films adsorbed at the oil-water interface.

Time-dependent surface viscosities are reported for films adsorbed from binary mixtures of the proteins alpha-lactalbumin, beta-lactoglobulin and beta-casein. The measurements were made at a planar interface between n-tetradecane and various protein solutions (10(-3) wt% of each protein, pH 7, 25 degrees C) using a Couette-type torsion-wire surface viscometer operating at very low shear-rate. Differences in behaviour between simultaneous and sequential exposure of the pairs of proteins to the interface were investigated. Some experiments were performed with chemically modified beta-lactoglobulin samples whose disulphide bonds had been cleaved and blocked. Displacement of one protein by another (e.g. alpha-lactalbumin by beta-casein) is indicated by a sudden drop in surface viscosity immediately after addition of the second protein. In systems containing beta-lactoglobulin, the long-time surface viscosity is very sensitive to the adsorption time of beta-lactoglobulin prior to addition of the second protein. Blocking the disulphide bonds in beta-lactoglobulin leads to a much faster approach to a steady-state surface viscosity. This is interpreted in terms of a much more rapid unfolding of the disordered molecules of modified beta-lactoglobulin at the oil-water interface. We conclude that surface viscosity experiments give useful and sensitive information about competitive adsorption and cooperative interactions in mixed protein films.

Caseins↗
PubMed1989

The epidemiology of HIV transmission among paid plasma donors, Mexico City, Mexico.

Screening of blood product donations for antibody to HIV began in Mexico in May 1986. From June to October 1986, the HIV cumulative seroprevalence increased from 6.3 to 9.2% in a commercial plasma collection center. Of the 281 people who donated the antibody-positive units, 62 (22.1%) had documented seroconversion during these 5 months. An epidemiologic study of 54 seropositive and 58 seronegative donors was carried out. The HIV serologic status did not change in any of these donors after repeat testing. Only 13.0% of the seropositives and 15.5% of the seronegatives had any of the known risk factors for AIDS. There was a direct relationship between frequency of plasma donation and the risk of being seropositive. A survey of employees disclosed the frequent re-use of disposable blood collection equipment. We conclude that HIV transmission had probably occurred in this plasma collection center.

Adult↗
PubMed1978

A sensitive analytical method for pyrrolizidine alkaloids. The mass spectra of retronecine derivatives.

The pyrrolizidine alkaloids in Senecio jacobaea can be hydrolyzed to the common base, retronecine, and derivatized to form the bistrifluoroacetate, bisheptafluorobutyrate, diacetate and bistrimethylsilyl ether. The analysis of the fluorinated compounds by electron capture provides sensitivity for detection of these alkaloids. The bond weakening effect in the ion formed on electron impact, between the allylic carbon and alkyl ester oxygen due to the electron withdrawing fluorinated groups of the ester, changes the driving force for fragmentation from the nitrogen alpha-cleavage reaction to a charge site migration. This yields alkyl-oxygen bond cleavage and formation of a stabilized allylic cation which is the base peak.

Chromatography, Gas↗
PubMedDate not supplied

Laxatives and faecal incontinence in long-term care.

High levels of faecal incontinence and laxative use in long-term care settings for older people are revealed in this study. Further research, together with more considered prescribing policies are needed, the authors suggest.

Activities of Daily Living↗
PubMedDate not supplied

Sequential audits of geriatric care: measuring change in structure and process and the contribution of clinical audit.

BACKGROUND: Sequential audits of care in geriatric practice can demonstrate improvement in its content and quality, and identify its strengths and weaknesses. However, there are problems in such sequential audit, particularly if it depends on data entry by lay staff rather than trained researchers. These include: changes in staff and patients from one audit to the next; having to take into account instances where the desired standards are already in place and therefore no further improvement can be shown, or where initial standards are so low that only improvement can take place. OBJECTIVES: To demonstrate methods of analysis of sequential audits in long-term care for elderly people and in geriatric day hospital practice designed to overcome these difficulties. DESIGN: Audit packages for long-term care and for care provided by geriatric day hospitals have been evaluated in each case by analysing two audit cycles carried out at eight and six month intervals respectively. METHODS: The Royal College of Physicians CARE scheme for audit of long-term care was carried out in 17 locations (nursing homes and geriatric long-stay wards) in two cycles at an interval of eight months. The Royal College of Physicians audit scheme for geriatric day hospitals was carried out in 27 day hospitals in two cycles at an interval of six months. A different method of analysis and presentation of results was devised for each of the two projects. RESULTS AND CONCLUSION: The two methods of analysis and presentation of data used to evaluate the effect of sequential audits reveal the ups and downs in the standards of care provided by the different institutions for the care of the elderly, and in the standards of care experienced by individuals resident in the same long-term institutions. Overall, sequential audits show that improvement outweighs deterioration in all domains of geriatric care, and suggest that audit contributes to this improvement.

Aged↗