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Biomedical subjects

L A Shaw

Publications and source records attributed to L A Shaw.

16 recordsLinked to original sources
PubMed2001

Children's, adolescents', and young adults' thinking about different types of disagreements.

Individuals' thinking about different types of disagreements was examined. Ninety-six participants in third grade (mean age = 8 years 9 months), seventh grade (mean age = 13 years 2 months), and college (mean age = 21 years 10 months) judged the acceptability of believing and acting on different types of beliefs with which they disagree, the attributes of the persons with whom they disagree, and the relative importance of cultural uniformity or diversity of belief. Findings indicated that participants' thinking did not simply become more tolerant with age; their thinking at all ages was constrained by both the realm over which there was disagreement and the form of the disagreement. At all ages, participants judged that some disagreements were acceptable and some unacceptable, described disagreeing others in terms of different (more or less positive) attributes, and judged that diversity of belief was important in some realms but uniformity was preferable in others.

Adolescent↗
PubMed2001

When surrogate decision-making is not straightforward. Guidelines for nurse administrators.

When ethical or pragmatic questions arise concerning surrogate decision-making, nurse administrators often are consulted, so they must be knowledgeable about current legislation as well as the surrogate decision-maker's role and ethical obligations. Case exemplars are presented in this article to facilitate the reader's awareness on how value conflicts and communication failures can complicate surrogate decision-making. Recommendations for clinical practice and research are presented.

Decision Making↗
PubMed1999

The testimony of elderly victim/witnesses and their impact on juror decisions: the importance of examining multiple stereotypes.

The goal of the current investigation was to determine how jurors may be influenced by elderly victim/witnesses. Stereotypes of elderly victim/witnesses were hypothesized to differentially impact jurors' perceptions and decisions. Participants (255 college and 229 community members who were jury-eligible) read a trial summary describing the aggravated assault of a man. The described case hinged on the victim's eyewitness identification of the defendant. The description of the victims was varied in order to examine five types of victim/witnesses: (1) a generic adult victim, described as being 31 years of age, (2) a generic elderly witness, described as being 66 years of age, (3) a 66-year-old senior citizen described to elicit the vulnerable-senior stereotype, (4) a 66-year-old grandfather, and (5) a 66-year-old statesman. Contrary to expectations, no significant differences were found between the college and community samples. Further, ratings of the victims' believability did not vary as a function of the different victim types. However, verdict differences were found for the different victim types. The proportion of guilty verdicts awarded in the statesman condition was significantly higher than those awarded when the victim was a generic adult, senior citizen, or grandfather. A significant difference was also found between the vulnerable senior citizen and the generic elderly case, with the generic elderly victim receiving a greater proportion of guilty verdicts than the vulnerable senior citizen.

Adult↗
PubMed1998

Tolerance and intolerance: children's and adolescents' judgments of dissenting beliefs, speech, persons, and conduct.

Tolerant and intolerant judgments of different types of dissent were examined. One hundred sixty participants (aged 7.3, 10.4, 13.6, and 20.1) made judgments about dissenting beliefs, speech, practices, and people engaged in those practices. Across all ages, participants were more tolerant (1) of the holding of dissenting beliefs than of their expression, (2) of the expression of beliefs than of the persons engaged in acts based on those beliefs, and (3) of the persons than of the acts. Tolerance of dissenting beliefs and speech increased with age. Although, at all ages, participants were intolerant of the practices, they were relatively more tolerant of practices grounded in cultural contexts. Participants were more tolerant of people espousing dissenting information than dissenting values. We concluded that tolerance and intolerance coexist at all ages and hinge on what individuals are asked to tolerate and on the sense in which they are asked to tolerate it.

Adolescent↗
PubMed1997

Combined administration of 5-HT2 and thromboxane A2 antagonists: effects on platelet aggregation and isolated cardiac muscle.

1. To investigate possible mechanisms underlying the ability of combined administration of a 5-hydroxytryptamine2 (5-HT2) antagonist and a thromboxane A2 antagonist to reduce reperfusion-induced arrhythmias, the effects of these drugs alone and in combination on platelet aggregation and on cardiac muscle were determined. 2. Platelet aggregation was measured in whole blood obtained from anaesthetized rats. Concentrations of 5-HT (10 microM) and the thromboxane A2 mimetic U46619 (1 microM) which did not cause aggregation themselves, enhanced the responses to ADP (0.1 microM) and to collagen (1 microgram ml-1). For example, the response of 1.0 +/- 0.5 omega to ADP alone was increased significantly to 6.4 +/- 1.0 omega by 5-HT, 15.5 +/- 2.8 omega by U46619, and 17.3 +/- 1.3 omega when U46619, 5-HT and ADP were added together. 3. In further experiments blood was obtained from rats which had received either the 5-HT2 antagonist, ICI 170,809 (1 mg kg-1), or the thromboxane A2 antagonist. ICI 192,605 (1 mg kg-1 min-1), or both in combination. When ADP was used as the primary aggregating agent, the ability of U46619 alone, or together with 5-HT, to enhance responses was reduced significantly by ICI 192,605 alone and in combination with ICI 170,809. Similar results were obtained with lower doses of ICI 170,809 (0.3 mg kg-1) and ICI 192,605 (0.3 mg kg-1 min-1). 4. When collagen was used as the primary aggregating agent ICI 170,809 (1 mg kg-1) reduced the response to 5-HT (5.0 +/- 0.8 omega versus 10.9 +/- 1.2 omega in controls), and ICI 192,605 (1 mg kg-1 min-1) reduced the response to U46619 (6.8 +/- 2.5 omega versus 11.2 +/- 2.2 omega in control). The greatest reduction of platelet aggregation was seen in blood from rats which had received both antagonists, with the response to U46619 plus 5-HT plus collagen being 2.7 +/- 0.6 omega compared to 14.2 +/- 1.7 omega in controls. In contrast, there was no significant attenuation of platelet aggregation in blood from rats which had received the lower doses of each antagonist alone. Only the combination of ICI 170,809 (0.3 mg kg-1) and ICI 192,605 (0.3 mg kg-1 min-1) reduced the response to U46619 plus 5-HT plus collagen (7.6 +/- 1.4 omega versus 15.0 +/- 0.5 omega in controls). 5. In rat isolated ventricular muscle preparations, ICI 170,809 increased the effective refractory period; e.g. from 39 +/- 4 to 86 +/- 18 ms, 10 min after adding 30 microM to left papillary muscles. ICI 192,605 did not increase the effective refractory period itself and did not alter the ability of ICI 170,809 to prolong the effective refractory period. In the presence of 100 microM ICI 192,605, ICI 170,809 (30 microM) increased the effective refractory period from 38 +/- 7 to 100 +/- 30 ms. 6. These results indicate that the previously observed antiarrhythmic activity of combined administration of the higher doses of ICI 170,809 and ICI 192,605 is unlikely to be due to direct effects on cardiac muscle but could be a consequence of reduced platelet aggregation.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1996

Suppression of reperfusion-induced arrhythmias with combined administration of 5-HT2 and thromboxane A2 antagonists.

1. The effects of the 5-HT2 antagonist, ICI 170,809 and the thromboxane A2 antagonist, ICI 192,605, given alone and in combination (n = 12 per group), were examined in anaesthetized rats. Haemodynamics and arrhythmias induced by permanent coronary artery occlusion or by reperfusion after 5 min of ischaemia were monitored. 2. In a study on reperfusion-induced arrhythmias, the only significant effect of ICI 170,809 (1 mg kg-1, i.v.) was a reduction in the number of ventricular premature beats (VPBs). ICI 192,605 (1 mg kg-1 min-1, i.v.) did not alter reperfusion-induced arrhythmias. However, in combination, when compared with controls, these drugs caused significant reductions in the incidence of ventricular tachycardia (VT), 100% to 58%; ventricular fibrillation (VF), 92% to 33%; and the mortality due to sustained VF, 67% to 17%. There was also a significant reduction in the number of VPBs following reperfusion. 3. In a second study with lower doses of drugs, ICI 170,809 (0.3 mg kg-1) and ICI 192,605 (0.3 mg kg-1 min-1) had no significant effects on reperfusion-induced arrhythmias either alone or in combination. 4. A third study examined the effects of the higher doses of the drugs on ischaemia-induced arrhythmias. Neither drug alone, nor in combination, altered the incidence of ischaemia-induced VT, VF, the mortality, or the number of VPBs. 5. These results indicate that, in contrast to the administration of either drug alone, combined administration of a 5-HT2 antagonist and a thromboxane A2 antagonist caused marked suppression of reperfusion-induced but not ischaemia-induced arrhythmias.

Animals↗
PubMed1991

Effect of aspartame-derived phenylalanine on neutral amino acid uptake in human brain: a positron emission tomography study.

The possible effects of elevation of the plasma phenylalanine level secondary to the ingestion of aspartame on brain amino acid uptake in human subjects have been investigated by means of positron emission tomography (PET). 1-[11C]Aminocyclohexanecarboxylate [( 11C]ACHC) is a poorly metabolized synthetic amino acid that crosses the blood-brain barrier by the same carrier that transports naturally occurring large neutral amino acids. Quantitative test-retest PET studies were performed on 15 individuals. Seven received two identical baseline scans, whereas eight received a baseline scan followed by a scan performed approximately 40-45 min following ingestion of an orange-flavored beverage containing 34 mg/kg of body weight of the low-calorie sweetener aspartame, a dose equivalent to the amount in 5 L of diet soft drink consumed all at once by the study subjects, weighing an average of 76 kg. The 40-45-min interval was selected to maximize the detection of possible decreases in ACHC uptake resulting from increased competition for the carrier, because the plasma phenylalanine level is known to peak at this time. We observed an 11.5% decrease in the amino acid transport rate constant K1 and a smaller decrease in the tissue distribution volume of ACHC (6%). Under conditions of normal dietary use, aspartame is thus unlikely to cause changes in brain amino acid uptake that are measurable by PET.

Amino Acids↗
PubMed1989

Sonography of the puerperal uterus.

Thirty-seven patients who delivered singleton pregnancies were followed by serial sonograms during the first 2 weeks of the puerperal period to evaluate uterine involution. Significant correlation was found between birthweight and uterine size during this period. No correlation was found between regressing uterine size and route of delivery, parity, or method of infant feeding. Variations in normal uterine, endometrial, and adnexal appearance are described as knowledge of these changes is necessary to appreciate pathologic conditions.

Female↗