The circadian variation of cardiovascular stress levels and reactivity: relationship to individual differences in morningness/eveningness.

Two studies assessed the circadian variation of cardiovascular responses to stress in healthy and coronary artery disease (CAD) populations. In within-subjects designs, stressors were administered to healthy male subjects and male CAD patients both in the morning and afternoon, and subjects were classified as either morning or evening types using the Morningness-Eveningness Questionnaire (Horne & Ostberg, 1976, International Journal of Chronobiology, 4, 97-110). No consistent circadian variation in blood pressure or heart rate responses was observed in the aggregate sample of either healthy subjects or CAD patients.

Mental stress as a trigger of myocardial ischemia and infarction.

Recent research on the effects of behavioral activities on myocardial ischemia in coronary artery disease patients has provided a pathophysiologic model for understanding the mechanisms by which mental stress can trigger clinical cardiovascular events. This article reviews epidemiologic research implicating psychosocial stress as an acute trigger of myocardial infarction in patients with pre-existing coronary artery disease, and evidence for the pathophysiologic effects of acute mental stress in individuals with pre-existing coronary artery disease. Via its actions on the central and autonomic nervous systems, stress can produce a cascade of physiologic responses in vulnerable individuals that may lead to myocardial ischemia, ventricular fibrillation, plaque rupture, or coronary thrombosis.

Circadian variation of ambulatory myocardial ischemia. Triggering by daily activities and evidence for an endogenous circadian component.

Background: The morning peak in myocardial ischemia has been related to diurnal variations in physical and mental activities and to postural changes upon awakening. This study assesses (1) the effects of exogenous activity triggers at different times of the day and (2) the contribution of an endogenous (ie, activity- and posture-independent) circadian vulnerability for ambulatory ischemia.

Methods And Results: Sixty-three stable coronary artery disease patients underwent ambulatory ECG monitoring and completed a structured diary assessing physical and mental activities.

The impact of disease severity on the informed consent process in clinical research.

Purpose: To assess the efficacy of informed consent in subjects differing in disease severity, ranging from those with immediately life-threatening disease to healthy volunteers.

Subjects And Methods: A total of 127 subjects, enrolled in four types of clinical research protocols, were tested. Subjects completed questionnaires before entry into the protocol, within 24 hours of signing the primary protocol's consent document, and 4 to 6 weeks after entry.

Triggers of myocardial ischemia during daily life in patients with coronary artery disease: physical and mental activities, anger and smoking.

Objectives: This study assessed the potency of physical and mental activities and emotions (anger and anxiety) and smoking and other substance use as proximate triggers of ischemia in patients with coronary artery disease during daily life.

Background: Myocardial ischemia occurs during a wide variety of activities in patients with coronary artery disease, but frequency and relative potency of physical and mental activities, smoking and use of caffeine and alcohol as triggers of ischemia during daily life have not been established.

Methods: Patients (n = 63) with coronary artery disease and evidence of out-of-hospital ischemia kept a validated structured diary of physical and mental activities and psychologic states while undergoing ambulatory electrocardiographic monitoring for 24 to 48 h.

First-trimester Down syndrome screening: free beta-human chorionic gonadotropin and pregnancy-associated plasma protein A.

Objective: Our purpose was to determine the feasibility of a first-trimester Down syndrome screening protocol including free beta-human chorionic gonadotropin and pregnancy-associated plasma protein A.

Study Design: First-trimester maternal blood samples from 22 Down syndrome and 483 control cases were assayed for free beta-human chorionic gonadotropin and pregnancy-associated plasma protein A by enzyme-linked immunosorbent assay procedures. False-positive and detection rates were determined on the basis of Down syndrome risks calculated from the levels of biochemical markers and maternal age.

Prenatal maternal dried blood screening with alpha-fetoprotein and free beta-human chorionic gonadotropin for open neural tube defect and Down syndrome.

Objective: Our purpose was to evaluate second-trimester prenatal screening for open neural tube defects and Down syndrome by use of dried blood specimen collection and transport.

Study Design: A prospective study of 7497 dried blood specimens from patients <35 years old was performed. Specimens were assayed for maternal blood alpha-fetoprotein and free beta-human chorionic gonadotropin.

Molecular analysis of neurotransmitter transport into secretory vesicles.

Molecular cloning of the transport proteins involved in packaging monoamines and ACh into secretory vesicles has implicated their activity in neural degeneration as well as signaling. Future studies will explore further the mechanism of active transport, its regulation, and the membrane trafficking of the proteins with the long-term goal of understanding how the regulation of transmitter release and, in particular, quantal size influences information processing and behavior. In addition, the bioenergetics of vesicular GABA and glutamate transport suggests that the proteins responsible for these activities may belong to a distinct gene family.

A molecular analysis of vesicular amine transport.

To package classical neurotransmitters into vesicles so that their release can be regulated by activity, neuronal cells express a set of specific vesicular transport proteins. We have used selection in MPP+ to clone the cDNAs encoding two vesicular monoamine transporters, the first members of this novel gene family that now also includes the vesicular transporter for acetylcholine. The sequences show similarity to several bacterial antibiotic resistance proteins, further supporting a role in detoxification and possibly Parkinson's disease.

Enhanced twin pregnancy detection within an open neural tube defect and Down syndrome screening protocol using free-beta hCG and AFP.

We have applied our multimarker approach of maternal serum alpha-fetoprotein (AFP) and free-beta human chorionic gonadotropin (hCG) for Down syndrome screening to multiple gestations to assess its efficacy for improved detection of twin and triplet pregnancies. This study matched 225 cases of twin pregnancy and 39 cases of triplet pregnancy each with ten singleton pregnancies based on gestational week, race, time to receive sample, time of year of sample, and geographical area. The ratios of the MOM for each group at the tenth, 50th, and 90th percentiles were compared by the Wilcoxon test.

Prothrombotic effects of environmental stress: changes in platelet function, hematocrit, and total plasma protein.

Mental stress can affect a range of variables relevant to hemostasis and thrombosis. However, research has not clarified whether these effects occur as part of a generalized sympathoadrenal response or whether stress-induced increases in catecholamines and blood pressure have selective and independent effects on hematologic variables. This study assessed the effects of mental and cold pressor stress on platelet activation, hematocrit, and total plasma protein and the relationship of these changes to sympathoadrenal and hemodynamic mechanisms.

Time course and mechanisms of decreased plasma volume during acute psychological stress and postural change in humans.

In this study, we examined the effects of psychological stress on calculated plasma volume, the relationship of these changes to changes in hematologic and hemodynamic factors, and the time course of plasma volume changes. Plasma volume changes were assessed using mass densitometry techniques, which measured changes in blood and plasma density. Hematologic and hemodynamic variables were assessed in 40 healthy men and women during a mental arithmetic (math) or benign reading task and during postural change (standing).

The treatment of non-HIV-related conditions in newborns at risk for HIV: a survey of neonatologists.

Objectives: The purpose of this study was to examine attitudes of neonatologists about treatment of conditions unrelated to the human immunodeficiency virus (HIV) for critically ill newborns at risk for HIV.

Methods: Questionnaires were mailed to the 1508 members of the Section on Perinatal Medicine of the American Academy of Pediatrics; 63% completed the survey (n = 951). The survey included structured questions about treatment for hypothetical cases and open-ended questions eliciting reasons for decisions.

Mental stress-induced ischemia in the laboratory and ambulatory ischemia during daily life. Association and hemodynamic features.

Background: The purpose of this study was to determine the correspondence of mental stress-induced ischemia in the laboratory with ambulatory ischemia and to assess the relationship between hemodynamic responses to mental stress and the occurrence of ischemia. Although exercise testing is usually used to elicit myocardial ischemia, ischemia during daily life usually occurs at relatively low heart rates and in the absence of strenuous physical exercise. Mental stress has been shown to trigger ischemic events in the laboratory at lower heart rates but at blood pressures comparable to exercise.

Defensive hostility: relationship to multiple markers of cardiac ischemia in patients with coronary disease.

Three studies assessed whether the combined traits of hostility and defensiveness identify a group of hostile individuals with functionally severe coronary artery disease (CAD). CAD patients completed the Cook-Medley Hostility Inventory (Ho) and the Marlowe-Crowne Social Desirability Scale (MC). Patients were classified into 4 groups: defensive hostile (DH: high Ho, high MC), low hostile (LH: low Ho, low MC), high hostile (HH: high Ho, low MC), and defensive (Def: low Ho, high MC).

Induction of silent myocardial ischemia with mental stress testing: relation to the triggers of ischemia during daily life activities and to ischemic functional severity.

Objectives: This study examined the relations among the triggers of ischemia during the activities of daily life, mental stress-induced ischemia in the laboratory and functional severity of ischemia on exercise testing.

Background: Myocardial ischemia is readily induced with exercise testing, but most episodes of ischemia in daily life occur during relatively sedentary activities. Although mental and emotional arousal are known to trigger myocardial ischemia, mental stress testing induces ischemia in only approximately 50% of patients with active coronary disease.

Triggers of angina and ST-segment depression in ambulatory patients with coronary artery disease: evidence for an uncoupling of angina and ischemia.

This study evaluated daily-life physical and mental triggers of painful and painless myocardial ischemia and of anginal pain in patients with coronary artery disease (CAD) by using ambulatory electrocardiographic monitoring and a structured diary. Eighty-five percent of ambulant ischemic episodes occurred without chest pain; 66% of anginal pain reports were made in the absence of ischemic ST-segment depression. Chest pain reports in the absence of ischemia could not be attributed to "borderline" ST-segment changes.

Effects of acute mental stress on serum lipids: mediating effects of plasma volume.

The present study assessed the acute effects of mental stress (mental arithmetic) on serum cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C), and the extent to which stress-induced changes are attributable to decreases in plasma volume. Total cholesterol, triglycerides, HDL-C, and LDL-C were assessed in 18 healthy men (35 +/- 7 years) during a resting baseline (30 minutes), challenging mental arithmetic (math; 10 minutes), and recovery (30 minutes). Five additional subjects served as controls receiving no stress intervention.

Chromosomal rearrangement segregating with adrenoleukodystrophy: associated changes in color vision.

A patient from a large kindred with adrenoleukodystrophy showed profound disturbance of color ordering, color matching, increment thresholds, and luminosity. Except for color matching, his performance was similar to blue-cone "monochromacy," an X chromosome-linked recessive retinal dystrophy in which color vision is dichromatic, mediated by the visual pigments of rods and short-wave-sensitive cones. Color matching, however, indicated that an abnormal rudimentary visual pigment was also present.

Stability of intact chorionic gonadotropin (hCG) in serum, liquid whole blood, and dried whole-blood filter-paper spots: impact on screening for Down syndrome by measurement of free beta-hCG subunit.

The use of multiple maternal serum biochemical markers in screening for Down syndrome is gaining worldwide acceptance. We sought to study the impact of the potential instability of intact human chorionic gonadotropin (hCG) on free beta-hCG subunit, a marker that has recently been used successfully in such screening. We found that, in practice, any changes in free beta-hCG due to the instability of intact hCG do not inhibit the effectiveness of free beta-hCG as a marker for Down syndrome.

Automated physical activity monitoring: validation and comparison with physiological and self-report measures.

Physical activity can be assessed via self-report, via physiological measures such as heart rate and oxygen uptake, or via automated monitor. An electronic accelerometer-based physical activity device (Actigraph) has been reported as an improvement over other activity measurement techniques in terms of utility and accuracy. Four studies provide systematic validation and reliability testing for this device and comparisons with other techniques for assessing daily activities.

Hostility and myocardial ischemia in coronary artery disease patients: evaluation by gender and ischemic index.

Two studies assess relationships of hostility to extent and severity of exercise-induced cardiac ischemia and daily life ischemia in patients with coronary artery disease (CAD). CAD patients (N = 80) who underwent exercise tomographic thallium testing to assess myocardial perfusion completed the Cook-Medley Hostility Inventory (Ho). A Composite Hostility (Chost) score obtained from the Ho scale was also used.

Mental stress and myocardial ischemia. Correlates and potential interventions.

In past years, indirect evidence has suggested a link between mental stress and coronary artery disease. Recent research in coronary artery disease patients has confirmed the observation that mental stress is a potent trigger of myocardial ischemia in both the laboratory and the field. The pathophysiologic effects of mental stress appear to operate via alterations in both myocardial oxygen demand and supply.