Biomedical subjects
Publications and source records attributed to W Sumner.
A funnel-shaped shield of 1 to 2 cm diameter at the mouth of a needle cap is shown to be effective at decreasing the number of accidental misses occurring in a recapping trial. An argument is made for recapping needles and incorporating new needle cap designs in a revision of the CDC guideline on needle disposal.
Hospital employees are at risk for numerous possible complications of accidental needlesticks. The mechanisms of such accidents suggest that many are preventable. This article presents a simple but novel revision of the needlecap which facilitates resheathing of a used needle. With routine use the hospital environment could be made safer for virtually all employees at almost no additional cost. Ultimate hospital savings could be significant through prevention of injury.
We have sequenced the 480 base pair (bp) repeating unit of the 5S RNA genes of the Dipteran fly Calliphora erythrocephala and compared this sequence to the three known 5S RNA gene sequences from the Dipteran Genus Drosophila (1,2). A striking series of five perfectly conserved homologies identically positioned within the 5' flanks of all four Dipteran 5S RNA coding regions has thus been identified. The spacing (12-13 bp) between all of these homologies is typical of A form rather than B form DNA. Given that the eukaryotic 5S RNA gene specific initiation factor TFIIIA (3) is a DNA unwinding protein (4), a role for these Dipteran 5' flank homologies in initiation site selection on 5S RNA genes transiently unwound for transcription is suggested. One of the Dipteran homology blocks is highly conserved in sequence and position in all but one of the eukaryotic 5S RNA gene sequences known to date (17/18 genes). Its sequence (consensus: TATAAG) and position (average center: -26 bp) are highly reminiscent of the polymerase II gene 'TATA' box (5).
Anthramycin can form a stable complex with DNA which does not dissociate upon repeated ethanol precipitations. The complex forms in less than one hour at pH 5.5. Bound anthramycin seems to be located in the minor groove of the DNA helix in the anthramycin DNA complex, since methylation of adenosine residues at N-3 by dimethylsulfate is reduced. The anthramycin-DNA complex is resistant to digestion by an excess of a number of restriction enzymes. Anthramycin can be removed from DNA by incubation at acid pH. The released DNA can then be cleaved by restriction enzymes. Anthramycin-DNA complexes can be acted upon by T4 polynucleotide ligase to form longer DNA molecules. The ability of anthramycin to form a stable but reversible complex which is not cleaved by restriction enzymes but can engage in joining reactions may allow a wider variety of DNA fragments to be more readily constructed in vitro.
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OBJECTIVE: To describe smokers' participation in cigarette continuity programs and the prevalence and structure of cooperative teams of smokers. METHODS: Cross-sectional survey of smoking histories and continuity-program participation by individuals and their family members in a convenience sample of 176 current smokers at the University of Kentucky Chandler Medical Center, Lexington. Fisher exact test or chi2 tests were used to compare proportions. RESULTS: One of 3 smokers collected coupons for a continuity program. Three quarters of the collectors redeemed their own coupons, and one quarter gave coupons to another collector. Coupon collectors reported an average team size of more than 2 members. One fifth of collectors were teammates with another generation of family members, and one quarter of collectors aged 24 to 35 years were teammates with their children. Smokers were often aware of their relatives' coupon-collecting habits. CONCLUSIONS: Continuity programs have been a popular means of reinforcing smoking, especially within families and groups of friends. Continuity programs are novel in encouraging smoking and brand loyalty between generations. Continuity-program participants need to be aware of the risk of promoting smoking initiation by their children. Health advocates could use similar strategies to promote smoking cessation and prevention within families and other social groups.
CONTEXT: Time preference (how preference for an outcome changes depending on when the outcome occurs) affects clinical decisions, but little is known about determinants of time preferences in clinical settings. OBJECTIVES: To determine whether information about mean population time preferences for specific health states can be easily assessed, whether mean time preferences are constant across different diseases, and whether under certain circumstances substantial fractions of the patient population make choices that are consistent with a negative time preference. DESIGN: Self-administered survey. SETTING: Family physician waiting rooms in four states. PATIENTS: A convenience sample of 169 adults. INTERVENTION: Subjects were presented five clinical vignettes. For each vignette the subject chose between interventions maximizing a present and a future health outcome. The options for individual vignettes varied among the patients so that a distribution of responses was obtained across the population of patients. MAIN OUTCOME MEASURE: Logistic regression was used to estimate the mean preference for each vignette, which was translated into an implicit discount rate for this group of patients. RESULTS: There were marked differences in time preferences for future health outcomes based on the five vignettes, ranging from a negative to a high positive (116%) discount rate. CONCLUSIONS: The study provides empirical evidence that time preferences for future health outcomes may vary substantially among disease conditions. This is likely because the vignettes evoked different rationales for time preferences. Time preference is a critical element in patient decision making and cost-effectiveness research, and more work is necessary to improve our understanding of patient preferences for future health outcomes.
OBJECTIVE: The objective of this study was to determine rheumatoid arthritis (RA) patients' preferences for validated health state scenarios depicting glucocorticoid adverse events, predictors of these preferences, and psychometric properties of different preference techniques in this population. METHODS: Preferences were elicited by rating scale and time trade-off methods. Time trade-offs included trading current health for either time spent alive in an adverse health state for chronic conditions (time trade-off) or time spent in a sleeplike state for acute conditions (sleep trade-off). RESULTS: A total of 107 subjects with long-standing RA participated in the preference interviews. Mean preference values (rating scale/trade-off) were lowest for serious fracture adverse events, including hip fracture requiring a nursing home stay (0.55+/-0.22/0.76+/-0.36) and vertebral fracture with chronic pain (0.59+/-0.23/0.67+/-0.35), and highest for cataracts (0.84 + 0.17/0.96 0.09) and wrist fracture (0.82+/-0.18/0.81+/-0.29). Rating scales had a stronger correlation (r= 0.88) with physician ranking of scenarios than trade-off methods (r = 0.31). All methods were feasible and demonstrated good reliability, while rating scale method showed better construct validity than trade-off techniques. CONCLUSION: Relative to their current health, RA patients assigned low preference values to many glucocorticoid adverse events, particularly those associated with chronic fracture outcomes. Results varied with the preference measure used, indicating that methodological attributes of preference determinations must be considered in clinical decision making.
BACKGROUND: Health outcome utility assessments generally assume procedural invariance. Preference reversals violating procedural invariance occur in economic scenarios when the assessment process shifts from a choice to a fill-in-the-blank task. PURPOSE: To determine if similar reversals occur in utility assessments. METHODS: One hundred thirty-six volunteer subjects completed 6 preference assessments of 4 personal health scenarios. Patients responded to otherwise identical tasks using either choice or fill-in-the-blank processes in a randomized crossover design. The authors determined the percentage of subjects preferring, or inferred to prefer, a given choice. RESULTS: Preference reversals occurred in all assessment scenarios. CONCLUSIONS: These preference reversals are a potential source of confusion for utility assessment and informed consent. They could be manipulated to achieve ends other than the best interest of patients. Anchoring or the prominence hypothesis may explain these findings.
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BACKGROUND: The American Board of Family Practice is developing a computer-based recertification process. An optimal implementation requires a formal model of family medicine, which will become the basis for a knowledge base. DESIGN: The proposed model of family medicine contains six entities: Population, Record, Agents of Change, Health States, Findings, and Courses of Action. The model illustrates 15 important relations between entities. For instance: Health States Lead to Health States, and Findings Associate with Health States. These two relations describe natural history, manifestations of disease, and the effects of medical interventions and risk factors. Because time is such an important aspect of primary care, nearly all numeric data are represented as graphs of possible values over time, called Patterns, which include details about periodicity. Patterns and other aspects of the model provide a means of describing covariance between observations, such as the influence of height on weight. RESULTS: The model reflects many family practice activities and suggests some formal descriptions of family practice. For instance, diagnostic activities focus largely on classifying early or short segments of Patterns in Findings. Most medical interventions attempt to alter either the probability distributions in a Lead-to relation or the impact of a Finding. CONCLUSION: The proposed model of family medicine could find uses in many applications, including computer-based tests, medical records, reference systems, and decision support tools.