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E Stewart

Publications and source records attributed to E Stewart.

83 records · Page 5Linked to original sources
PubMedDate not supplied

Reaction of a chemotherapeutic agent, 6-mercaptopurine, with a direct-acting, electrophilic carcinogen, benzo[a]pyrene-7,8-diol 9,10-epoxide.

The chemotherapeutic agent 6-mercaptopurine (6-MP) has been shown to react covalently with the ultimate carcinogenic metabolite of benzo[a]pyrene, 7-r,8-t-dihydroxy-9-t,10-t-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), in aqueous solution, forming a single adduct. NMR studies of the HPLC-purified product were consistent with its identification as 10(S)-(6'-mercaptopurinyl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo[a]pyrene. Reaction kinetics were analyzed by using both HPLC separation of the products formed and a spectrophotometric assay for adduct formation. A simple model in which direct reaction between 6-MP and BPDE takes place without formation of a physical complex was found to adequately predict the dependence of product ratios on 6-MP concentration. Variations in the observed rate constant for this reaction with changes in temperature, pH, and buffer concentration were determined and compared to the effects of these variables on the observed rate constant for BPDE hydrolysis. In each case, the processes were affected quite differently, suggesting that different rate-determining steps are involved. The data suggest that the reaction mechanism involves SN2 attack of the anion of 6-MP, formed by ionization of the sulfhydryl group, on carbon 10 of BPDE, resulting in a trans-9,10 reaction product.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMedDate not supplied

Urinary catheters: selection, maintenance and nursing care.

Catheterization is often undertaken without sufficient assessment, and the high rates of bacteriuria (10-20%) occurring in catheterized patients seem to be accepted (Ward et al, 1997). This article reviews catheter selection, maintenance and nursing care, highlighting problem areas and suggesting measures that may be taken to reduce the risk factors. A problem-solving approach, based on research evidence relating to catheter care, is presented. Often there is a simple solution to a problem, but treatments based on traditions or myths appear to be the first choice in many situations. This article aims to provide nurses with the evidence base required to establish and maintain a urinary drainage system safely.

Bacteriuria↗
PubMedDate not supplied

A controlled trial of intrauterine insemination for cervical factor and male factor: a preliminary report.

In a prospective, randomized, controlled trial, we evaluated the efficacy of intrauterine insemination (IUI) in 54 couples with cervical factor (CF) infertility and in 19 couples with male factor (MF) infertility. The diagnoses were confirmed by strict criteria and all other etiologies of infertility were ruled out prior to entry. Patients served as their own controls with alternating cycles of washed sperm IUI and whole-ejaculate intracervical insemination (ICI). In 113 paired cycles (mean 2.1 pairs/patient; range 1-7 paired cycles), 13% (n = 7) of CF patients became pregnant by IUI, 7% (n = 4) by ICI, and 6% (n = 3) by intercourse after missing inseminations. Seventy-one percent of IUI pregnancies occurred in the first 2 months. In 45 paired cycles for MF patients (mean 2.4 pairs/patient; range 1-6 paired cycles), two patients conceived, both in the first IUI cycle. These data suggest that pregnancies resulting from IUI occur during early treatment cycles.

Adult↗
PubMedDate not supplied

A strategy to reduce laxative use among older people.

Institutions can be places of routine and unquestioned practice in the administration of medications. In one mixed ward of psychogeriatric patients constipation was a common problem for which laxatives were routinely given. In this particular ward, many of the patients were receiving up to five different laxatives a day either orally or rectally. Dementia and being bed or chair-bound greatly increased the risk of chronic constipation. Excessive laxative use is another cause of chronic constipation. A review of practice and a decision implement a new approach was prompted by the arrival of new ward managers. The use of laxatives was stopped almost entirely and a new dietary regime was started. This article outlines how the changes were implemented.

Aged↗