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R D Platt

Publications and source records attributed to R D Platt.

8 recordsLinked to original sources
PubMed1993

Darwinian algorithms and the Wason selection task: a factorial analysis of social contract selection task problems.

In four experiments with 760 subjects, the present study examined Cosmides' Darwinian algorithm theory of reasoning: specifically, its explanation of facilitation on the Wason selection task. The first experiment replicated Cosmides' finding of facilitation for social contract versions of the selection task, using both her multiple-problem format and a single-problem format. Experiment 2 examined performance on Cosmides' three main social contract problems while manipulating the perspective of the subject and the presence and absence of cost-benefit information. The presence of cost-benefit information improved performance in two of the three problems while the perspective manipulation had no effect. In Experiment 3, the cost-benefit effect was replicated; and performance on one of the three problems was enhanced by the presence of explicit negatives on the NOT-P and NOT-Q cards. Experiment 4 examined the role of the deontic term "must" in the facilitation observed for two of the social contract problems. The presence of "must" led to a significant improvement in performance. The results of these experiments are strongly supportive of social contract theory in that cost-benefit information is necessary for substantial facilitation to be observed in Cosmides' problems. These findings also suggest the presence of other cues that can help guide subjects to a deontic social contract interpretation when the social contract nature of the problem is not clear.

Adult↗
PubMed1990

Comparison of the inhibitory effect of polyunsaturated fatty acids on prostaglandin synthesis. II. Fibroblasts.

In a previous publication we reported that PUFAs of the n-6 and n-3 series caused significant inhibition of synthesis of both PGE2 (28.4-92.8%) and PGF2 alpha (24.4-84.0%) in the oral squamous carcinoma cell line SCC-25. In this report we describe the inhibitory effect of the same acids on PG synthesis in normal human gingival fibroblasts under the same experimental conditions. It was found that a combination of EPA + DCHA (6:4), DCHA and ALA caused significant reduction in synthesis of PGE2 (10.1-87.8%) and PGF2 alpha (14.0-54.6%) at the four dose levels studied. The rank order of potency of acids in reduction of PG synthesis was: EPA + DCHA greater than DCHA greater than EPA greater than ALA greater than LA greater than DGLA greater than GLA. The data suggest that although PUFAs are effective inhibitors of PG synthesis by gingival fibroblasts and SCC-25, the fibroblast is less susceptible to the inhibitory effect of fatty acids.

Adult↗
PubMed1988

Piroxicam versus naproxen in the treatment of acute musculoskeletal disorders in athletes.

Safe and effective therapy for acute musculoskeletal disorders would be extremely useful for competitive athletes. These injuries are common in these patients, who are usually highly motivated to return to their previous level of activity and performance. Because nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to be useful in inflammation-associated conditions such as rheumatoid arthritis and osteoarthritis, it was believed that their use in competitive athletes may be warranted. This study compared the efficacy and tolerability of two NSAIDs, piroxicam and naproxen, in these patients. The patients included 34 men and women who had acute symptoms including restrictions of movement and limitation of physical activity as a result of sprains to the ankle, acromioclavicular joint, and interphalangeal joint of the hand or acute soft-tissue injury to the shoulder, knee, or about the hip. In a double-blind, comparative, parallel manner, patients were randomly allocated to receive piroxicam 40 mg daily for two days and then 20 mg once daily, or naproxen 500 mg twice daily for two days, then 375 mg twice daily. Both drugs improved virtually all measures of physical discomfort after three and seven days of treatment (p less than 0.0001). Three days after beginning the study, the mean reduction in spontaneous pain, swelling, and tenderness was statistically superior in the piroxicam group (p less than 0.05) compared with the naproxen group. After seven days of treatment, a marginally larger reduction in swelling was associated with piroxicam (p = 0.081); however, no other statistically significant difference was seen. Although improvements in physical movement and strength were assessed, no consistent conclusion could be reached because of the small sample size; no statistically significant differences were seen between the treatment groups with respect to such improvements. Patient and investigator assessments of efficacy and tolerability were primarily excellent or good for both drugs. It was concluded that piroxicam and naproxen are effective and well-tolerated short-term treatments for acute musculoskeletal injuries in athletes.

Acute Disease↗
PubMed1987

Effect of effervescent buffered aspirin on prostaglandin synthesis by human gingival fibroblasts.

Cultured human gingival fibroblasts were incubated with 14C-arachidonic acid (AA) at 37 degrees C for 2 hours. The metabolites formed were extracted from the cell-free medium in methanol, separated and identified by thin layer chromatography, using two solvent systems that allowed resolution of cyclooxygenase and lipoxygenase products. The predominant cyclooxygenase products were PGE2 and 6-keto-PGF1 alpha. PGA2, PGF2 alpha, PGD2, 15-keto-PGE2, TXB2 were also detected in smaller amounts. No detectable radioactivity corresponding to lipoxygenase products 5-HETE, 12-HETE, and 15-HETE was found. Incubation of fibroblasts with effervescent buffered aspirin (EBA) (.02%, .04%, .06%), or sodium bicarbonate, citric acid and aspirin, individually, (in concentrations equivalent to those present in EBA) resulted in stimulation of synthesis of PGs except PGE2 which was inhibited by EBA and aspirin.

Arachidonic Acid↗
PubMed1981

Proposal for a national autopsy data bank: a potential major contribution of pathologists to the health care of the nation.

This report highlights the salient deliberations of the Anatomic Pathology Committee of the College of American Pathologists (CAP) and of its consultants and advisors in formulating a proposal for the establishment of a National Autopsy Data Bank (NADB). It has constituted the major thrust of this Committee for the past five years and is presented in considerable detail in order to familiarize the pathology community and other interested parties with the plan, which, if implemented, would enable pathologists to contribute even further to the health care of the nation while concomitantly realizing benefits both individually and collectively. In order for the proposal to culminate in an optimally functioning NADB, the support and participation of a majority of, if not all, pathologists with autopsy responsibilities would be needed. Goals, objectives, justification, and merits, background, legal considerations, pilot studies, and management plans are discussed and the singular advantages that could accrue with implementation are delineated. If achieved, it would be the first time that any medical discipline or organization would have amassed such kinds of accurate biomedical information potentially so useful to so many for so little.

Autopsy↗