Ethnic differences in the myocardial and vascular reactivity to stress in normotensive girls.

Cardiovascular reactivity to stress has been proposed as a mechanism partially responsible for the increased prevalence of essential hypertension in African-Americans compared with whites. However, few studies have examined ethnic differences in cardiovascular reactivity among women. The present study evaluated potential ethnic differences in the cardiovascular reactivity to three laboratory stressors (postural change, video game challenge, forehead cold stimulation). The sample consisted of 171 normotensive girls (74 whites, 97 African-Americans) with a mean age of 11.1 +/- 2.7 years, all with positive family histories of essential hypertension. African-American girls showed higher resting diastolic blood pressures and higher resting total peripheral resistance compared with white girls. African-American girls also exhibited higher peak responses in systolic and diastolic blood pressure and total peripheral resistance and lower cardiac index responses during video game challenge and forehead cold stressor. The findings extend previous observations of ethnic differences in blood pressure reactivity to stress and indicate that concomitant increases in total peripheral resistance appear to account for the greater blood pressure reactivity in African-American girls.

Consistency of children's hemodynamic responses to laboratory stressors.

Hemodynamic responses to three standard laboratory stressors (i.e., postural change, video game, forehead cold) were evaluated in 341 children (170 males) who had a mean age of 11.2 +/- 2.6 years. Inter-task consistency was evaluated for five physiological parameters for all stressor pairings. Evidence of consistency in systolic and diastolic blood pressure, heart rate, cardiac output, and total peripheral resistance responses to all three stressors was observed. The highest and most consistent correlations across stressors were observed for cardiac output and total peripheral resistance responses. The need for clarification in the categorization of laboratory stressors used to measure reactivity is discussed.

Peak shift as a function of multiple schedules of reinforcement.

Pigeons were trained to respond to two stimuli on the wavelength continuum, 550 nm and 570 nm, each correlated with an independent schedule of reinforcement. The multiple schedule component in effect during 550 nm (S1) was always a variable-interval 1-min. During the 570-nm stimulus (S2) the second component of the schedule was either variable-interval 30-sec, 1-min, 2-min, 5-min, or extinction for different groups of birds. Generalization gradients were obtained after this training, with the following results: (1) response rate to S1 during training was related to the reinforcement frequency associated with S2; the distribution of responding during generalization testing was a function of the schedules of reinforcement used during training and the response rates they produced. Decreases in the relative frequency of reinforcement correlated with S2 resulted in increases in the distribution shift of responses away from S2 during generalization testing.

Mug shot exposure prior to lineup identification: interference, transference, and commitment effects.

The effects of viewing mug shots on subsequent identification performance are as yet unclear. Two experiments used a live staged-crime paradigm to determine if interpolated eyewitness exposure to mug shots caused interference, unconscious transference, or commitment effects influencing subsequent lineup accuracy. Experiment 1 (N = 104) tested interference effects. Similar correct decision rates were obtained for the mug shot and no mug shot groups from both perpetrator-present and absent lineups. Experiment 2 (N = 132) tested for commitment and transference effects. Results showed that the commitment group made significantly more incorrect identifications than either the control or the transference group, which had similar false-identification rates. Commitment effects present a serious threat to identification accuracy from lineups following mug shot searches.

E-mail marketing grows up: a primer for the managed care industry.

Managed care plans are jumping onto the electronic marketing bandwagon in a big way, taking advantage of not only the basic E-mail system but also expanding on that medium and developing creative vehicles to send the health plan's message. In this article, the author describes how E-mail technology is being used to hone the marketing edge in MCOs.

Promoting your environmental web site.

For just a modest investment of time and money, opportunities abound to increase site visibility on the Internet.

A preidentification questioning effect: serendipitously increasing correct rejections.

A study designed to test the effects of delay between crime and lineup on identification accuracy produced an unusually high rate of correct rejection from target-absent, simultaneous lineups (J. E. Dysart, 1999). Examining the procedures indicated that one question included in a preidentification questionnaire differed from those used previously. The question asked witnesses if they believed they would be able to correctly reject a target-absent lineup. An experiment (N = 138) was conducted to explore the impact of preidentification questions, including this new question, on witness accuracy. Results revealed that asking witnesses these questions, prior to viewing the lineup, significantly increased correct rejections of target-absent simultaneous lineups.

Eyewitness accuracy rates in sequential and simultaneous lineup presentations: a meta-analytic comparison.

Most police lineups use a simultaneous presentation technique in which eyewitnesses view all lineup members at the same time. Lindsay and Wells (R. C. L. Lindsay & G. L. Wells, 1985) devised an alternative procedure, the sequential lineup, in which witnesses view one lineup member at a time and decide whether or not that person is the perpetrator prior to viewing the next lineup member. The present work uses the technique of meta-analysis to compare the accuracy rates of these presentation styles. Twenty-three papers were located (9 published and 14 unpublished), providing 30 tests of the hypothesis and including 4,145 participants. Results showed that identification of perpetrators from target-present lineups occurs at a higher rate from simultaneous than from sequential lineups. However, this difference largely disappears when moderator variables approximating real world conditions are considered. Also, correct rejection rates were significantly higher for sequential than simultaneous lineups and this difference is maintained or increased by greater approximation to real world conditions. Implications of these findings are discussed.

Treatment of coexistent coarctation and aneurysm of the aorta with covered stent in a pediatric patient.

Intravascular stents have emerged as an effective alternative to surgery and balloon angioplasty in the treatment of native and recoarctation of aorta. Balloon angioplasty, although effective in the treatment of native coarctation of the aorta, is associated with several complications such as recoarctation, aneurysm formation, aortic dissection, and vascular injury. In this report, we present the use of a covered stent to treat a patient who developed recoarctation of the aorta with an associated aneurysm following balloon angioplasty of her native coarctation.

On the reduced intercellular adhesiveness of virally transformed BHK21 cells.

Baby hamster kidney fibroblasts (BHK21 cells) transformed by polyoma or Rous sarcoma viruses aggregate less than the untransformed parental cells when incubated in growth medium in a gyratory shaker for 18-24 h. This difference can be measured by electronic particle counting, or by filtering aggregated suspensions of 32P-labelled cells through bolting fabric. The aggregation of transformed derivatives is not enhanced by the presence, during aggregation of epsilon-amino caproic acid, an inhibitor of plasmin activation. Some lines of transformed BHK21 cells do not appear less adhesive than untransformed cells in a short-term aggregation assay, and none adheres markedly less well when seeded onto homotypic cell sheets. The decreased aggregation of transformed cells is consistent with suggestions that LETS protein is involved in intercellular adhesion of fibroblasts as well as in attachment of cells to non-cellular substrates. If so, the short-term aggregation of freshly trypsinized cells may depend on secretion of LETS from an intracellular pool.