Biomedical subjects
Publications and source records attributed to R Stafford.
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An outbreak of pseudomembranous colitis in an intensive care unit is described. This resulted in environmental contamination by Clostridium difficile. The outbreak could be traced to one patient who received several antibiotics over the preceding three months. A search was conducted for asymptomatic carriers among patient and staff but none were found. Aquisition of C. difficile from inanimate environmental sources was the most probable means of transmission of the organism. Its persistence in the hospital environment for several weeks, most likely as spores, suggests that patients who develop pseudomembranous colitis should be isolated, especially in areas of high antibiotic usage.
The detection of DNA-damaging agents by repair-deficient bacterial assays is based on the differential inhibition of growth of repair-proficient and repair-deficient bacterial pairs. The various methodologies used are described and recommendations are made for their improved use. In a survey of the literature through April 1979, 91 of 276 papers evaluated contained usable data, resulting in an analysis of 611 compounds that had been assayed in 1 or more of 55 pairs of repair-proficient and repair-deficient strains. The results indicate that (1) a liquid suspension assay is more sensitive than a spot (diffusion) test. In a review of the Escherichia coli polA assay, 45 compounds that gave "No Test" in the spot test were clearly positive or negative in the liquid suspension assay. (2) Of the 21 compounds analyzed by the E. coli polA assay and by other E. coli repair-deficient strains (e.g., rec, uvr, hcr, and exr derivatives of WP2 and AB1157), 10 were in complete agreement in all strains except uvrA strains. This indicates that strains other than polA+/polA- are useful for detecting DNA-damaging agents. However, in selecting strains for use in these assays, care should be taken to consider repair pathway specificity for particular compounds. (3) There was a 78% correspondence between results obtained with E. coli polA and Bacillus subtilis (H17/M45, 17A/45T) rec assay and between E. coli polA and Proteus mirabilis. (4) In a comparison of test results with carcinogenicity data, 44 of 71 (62%) carcinogenic compounds assayed by the polA system were positive, 10 (14%) were negative, and 17 (24%) gave No Test or doubtful results. 7 carcinogens were assayed by other E. coli strains and all were positive. 56 carcinogens were assayed in B. subtilis: 24 (43%) were positive, 9 (16%) were negative, and 23 (41%) gave No Test or doubtful results. Of the 7 carcinogens assayed in P. mirabilis, 6 (86%) were positive and 1 (14%) was negative. (5) The results were analyzed with respect to chemical classes. E. coli polA detected the highest percentage of hydroxylamines and alkyl epoxides. The B. subtilis rec assay detected the highest percentage of nitrosamines and sulfur and nitrogen oxides. It is concluded that some of these test systems are effective tools for the detection of DNA-damaging and potentially carcinogenic compounds, especially if the assay is done in liquid suspension and if more than 1 pair of tester strains is used. Advantages and disadvantages of the assay are discussed and suggestions are made for improvements in the system.
A retrospective chart review of 500 leukemia patients was carried out to analyze the role of oral pathoses in the presentation of leukemia and to determine those factors which affect the frequency of oral involvement during the initial clinical phases of the disease. The data indicate that oral pathoses were frequent signs or symptoms in patients with undiagnosed acute leukemia but were less prevalent in patients with undiagnosed chronic leukemia. Neither age nor sex appeared to be a significant factor affecting oral involvement. Oral signs of thrombocytopenia were the most prevalent complaint of patients seeking diagnosis for their leukemia because of an oral problem, and they were also most frequently responsible for oral problems found at initial physical examination. Head and neck lymphadenopathy was also a frequent presenting sign or symptom. Dentists were responsible for initiating the diagnosis of leukemia in a significant number of patients with acute nonlymphoblastic leukemia.
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In an era of healthcare reform, escalating costs, and constant change, methods of care delivery that will produce satisfactory patient outcomes while maintaining or reducing the cost of care must be developed. In an effort to meet this goal, Community General Hospital of Thomasville, North Carolina, implemented the Patient-Focused Care Delivery Model. This article explains the planning, implementation, and evaluation phases of this project. Positive and negative aspects of the change also are discussed.