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In the decade since the initial discovery and characterization of endothelin, its biology as a powerful vasoconstrictor has been dramatically demonstrated. Studies have clarified the existence of endothelin isoforms, complex mechanisms of biosynthesis, interaction with specific receptors, and pathogenic implications. We are on the brink of using endothelin antagonism as a clinical treatment for disease processes where endothelin plays an important role, including congestive heart failure and hypertension. Novel observations have been made about the unexpectedly profound contribution endothelins make to normal fetal maturation, especially in cardiac and enteric development.
STUDY OBJECTIVE - Our objective was to assess the prevalence of cardiac risk factors in a sample of urban paramedics and emergency department (ED) nurses.
METHODS - We asked 175 paramedics and ED nurses working at a busy, urban ED to complete a cardiovascular risk assessment. The survey asked subjects to report smoking history, diet, exercise habits, weight, stress levels, medication use, history of hypertension or cardiac disease, family history of cardiovascular disease (CVD), and cholesterol level (if known).
RESULTS - 129 of 175 surveys were returned (74% return rate) by 85 paramedics and 44 nurses. The percentages of paramedics and nurses at high or very high risk for cardiac disease were 48% and 41%, respectively. Forty-one percent of female respondents and 46% of male respondents were at high or very high risk. Cigarette smoking was reported in 19% of the paramedics and 14% of the nurses. The percentages of paramedics and nurses who reported hypertension were 13% and 11%, respectively. High cholesterol was reported in 31% of paramedics and 16% of nurses.
CONCLUSIONS - Forty-eight percent of paramedics and 41% of ED nurses at this center are at high or very high risk for cardiovascular disease, by self-report. Efforts should be made to better educate and intervene in this population of health-care providers in order to reduce their cardiac risk.
BACKGROUND - The increasing number of transgenic and targeted mutant mice with embryonic cardiac defects has resulted in the need for noninvasive techniques to examine cardiac structure and function in early mouse embryos. We report the first use of a novel 40-MHz ultrasound imaging system in the study of mouse cardiac development in utero.
METHODS AND RESULTS - Transabdominal scans of mouse embryos staged between 8.5 and 13.5 days of gestation (E8.5 to E13.5) were obtained in anesthetized mice. Atrial and ventricular contractions could be discerned from E9.5, and changes in cardiac morphology were observed from E9.5 to E13.5. Hyperechoic streaming patterns delineated flow through the umbilical, vitelline, and other major blood vessels. Diastolic and systolic ventricular areas were determined by planimetry of the epicardial borders, and fractional area change was measured as an index of contractile function. Significant increases in ventricular size were documented at each stage between E10.5 and E13.5, and the ability to perform serial imaging studies over 3 days of embryonic development is described. Finally, the detection of vascular cell adhesion molecule 1 (VCAM-1) homozygous null mutant embryos demonstrates the first example of noninvasive, in utero analysis of cardiac structure and function in a targeted mouse mutant.
CONCLUSIONS - We used 40-MHz echocardiography to identify key elements of the early mouse embryonic cardiovascular system and for noninvasive dimensional analysis of developing cardiac ventricles. The ability to perform serial measurements and to detect mutant embryos with cardiac defects highlights the usefulness of the technique for investigating normal and abnormal cardiovascular development.
BACKGROUND - Cardiac involvement is common in acute Lyme disease, and case reports suggest that cardiac abnormalities might also occur years after the primary infection.
OBJECTIVE - To determine the prevalence of cardiac abnormalities in persons with previously treated Lyme disease.
DESIGN - Population-based, retrospective cohort study with controls.
SETTING - Nantucket Island, Massachusetts.
PARTICIPANTS - From among 3703 adult respondents to a total-population (n = 6046) mail survey, 336 (176 case-patients and 160 controls) were randomly selected for clinical evaluation.
MEASUREMENTS - Current cardiac symptoms and major or minor abnormal electrocardiographic features, including heart rate; rhythm; axis; PR, QRS, and QT intervals; QRS structure; atrioventricular blocks; and ST-segment and T-wave changes.
RESULTS - Persons with Lyme disease (case-patients, n = 176) (mean duration from disease onset to study evaluation, 5.2 years) and persons without evidence of previous Lyme disease (controls, n = 160) did not differ significantly in their patterns of current cardiac symptoms and electrocardiographic findings, including heart rate (P > 0.2), PR interval (P = 0.15), QRS interval (P > 0.2), QT interval (P > 0.2), axis (P > 0.2), presence of arrhythmias (P > 0.2), first-degree heart block (P = 0.12), bundle-branch block (P > 0.2), and ST-segment abnormalities (P > 0.2). In multivariate analyses that adjusted for age, sex, and previous heart disease, a history of previously treated Lyme disease was not associated with either major (odds ratio, 0.78; P > 0.2) or minor (odds ratio, 1.09; P > 0.2) electrocardiographic abnormalities.
CONCLUSION - Persons with a history of previously treated Lyme disease do not have a higher prevalence of cardiac abnormalities than persons without a history of Lyme disease.
A method is presented for evaluating the amount of information a medical test provides about individual patients. Emphasis is placed on the role of a test in the evaluation of patients with a chronic disease. In this context, the yield of a test is best interpreted by analyzing the prognostic information it furnishes. Information from the history, physical examination, and routine procedures should be used in assessing the yield of a new test. As an example, the method is applied to the use of the treadmill exercise test in evaluating the prognosis of patients with suspected coronary artery disease. The treadmill test is shown to provide surprisingly little prognostic information beyond that obtained from basic clinical measurements.
Accessory atrioventricular pathways, the anatomical structures responsible for the preexcitation syndromes, may result from a developmental failure to eradicate the remnants of the atrioventricular connections present during cardiogenesis. To study whether preexcitation syndromes could also be transmitted genetically, we determined the prevalence of preexcitation in the first-degree relatives of 383 of 456 consecutive patients (84 percent) with electrophysiologically proved accessory pathways. We compared the observed prevalence of preexcitation among the 2343 first-degree relatives with the frequency reported in the general population (0.15 percent). For 13 of the 383 index patients (3.4 percent), accessory pathways were documented in one or more first-degree relatives. At least 13 of the 2343 relatives identified (0.55 percent) had preexcitation; this prevalence was significantly higher than that in the general population (P less than 0.0001). Identification of affected relatives may have been incomplete because clinical information was obtained only about symptomatic relatives. Patients with familial preexcitation have a higher incidence of multiple accessory pathways and possibly an increased risk of sudden cardiac death. Our data suggest a hereditary contribution to the development of accessory pathways in humans. The pattern of inheritance appears to be autosomal dominant.
The toxicities of chemotherapy continue to hamper dose escalation of specific chemotherapeutic agents. The impact of dose intensification upon survival will be assessed as clinical studies continue. Strategies to support chemotherapy dose intensification include BMT, use of CSFs and antiemetic drug combinations. Advances in symptom management will hopefully enhance quality of life for patients, whereas the development of chemoprotectant agents may allow specific organ toxicities to be avoided.