Flexible nanofilms coated with aligned piezoelectric microfibers preserve the contractility of cardiomyocytes.

The use of engineered cardiac tissue for high-throughput drug screening/toxicology assessment remains largely unexplored. Here we propose a scaffold that mimics aspects of cardiac extracellular matrix while preserving the contractility of cardiomyocytes. The scaffold is based on a poly(caprolactone) (PCL) nanofilm with magnetic properties (MNF, standing for magnetic nanofilm) coated with a layer of piezoelectric (PIEZO) microfibers of poly(vinylidene fluoride-trifluoroethylene) (MNF+PIEZO). The nanofilm creates a flexible support for cell contraction and the aligned PIEZO microfibers deposited on top of the nanofilm creates conditions for cell alignment and electrical stimulation of the seeded cells. Our results indicate that MNF+PIEZO scaffold promotes rat and human cardiac cell attachment and alignment, maintains the ratio of cell populations overtime, promotes cell-cell communication and metabolic maturation, and preserves cardiomyocyte (CM) contractility for at least 12 days. The engineered cardiac construct showed high toxicity against doxorubicin, a cardiotoxic molecule, and responded to compounds that modulate CM contraction such as epinephrine, propranolol and heptanol.

Hypertension and the risk of acute myocardial infarction in Argentina. The Argentine Factores de Riesgo Coronario en America del Sur (FRICAS) Investigators.

The relationship between a history of hypertension and the quality of its control in routine clinical practice and the risk of acute myocardial infarction was examined in a multicenter, case-control study conducted in Argentina between November 1991 and August 1994, within the framework of the FRICAS study. The cases were 939 patients with acute myocardial infarction and without a history of ischemic heart disease. The controls were 949 subjects identified in the same centers as the cases and admitted with a wide spectrum of acute disorders unrelated to known or suspected risk factors for acute myocardial infarction. The odds ratios and the 95% confidence intervals were derived from multiple logistic regression equations, including terms for age, gender, education, social status, exercise, smoking status, cholesterolemia, history of diabetes, body mass index, and family history of myocardial infarction. The quality of hypertension control was assessed with the most recent blood pressure reading reported by the subjects. Seventy-two percent of hypertensive cases and 62.6% of hypertensive controls had a history of antihypertensive therapy by self-report, when admitted to the medical center. The adjusted odds ratio for acute myocardial infarction due to hypertension was 2.58 (95% confidence interval, 2.08-3.19). The odds ratio was 2.42 (95% confidence interval, 1.88-3.11) when hypertensives reported that their greatest systolic value was below 200 mm Hg (moderate status) and 4.12 (95% confidence interval, 2.87-5.89) when it was above 200 mm Hg (severe status). When the highest diastolic blood pressure value was below 120 mm Hg (moderate status), the risk increased to 2.48 (95% confidence intervals, 1.90-3.24) and to 4.12 (95% confidence interval, 2.83-5.99) when it was above 120 mm Hg (severe status). If the most recent systolic blood pressure was less-than-or-equal140 mm Hg, the odds ratio was 2.59 (95% confidence interval, 1.96-3.41), and it was 3.42 (95% confidence interval, 2.40-4.87) when the value was >140 mm Hg. If the most recent diastolic blood pressure was less-than-or-equal90 mm Hg, the risk increased more than two fold (odds ratio=2.48; 95% confidence interval, 1.91-3.22), and if it was >90 mm Hg, it increased nearly four-fold (odds ratio=3.72; 95% confidence interval, 2.33-5.96). In smokers, the odds ratio was 2.28 in the absence of hypertension and increased to 7.51 when hypertension was present. In this Argentine population, hypertension is a strong and independent risk factor for acute myocardial infarction. In routine clinical practice, the control of blood pressure to levels below 140/90 seems to be required in order to reduce part (but not all) of the risk of acute myocardial infarction in hypertensive patients. (c) 2001 by CHF, Inc.

Case-control study of passive smoking at home and risk of acute myocardial infarction. Argentine FRICAS Investigators. Factores de Riesgo Coronario en América del Sur.

OBJECTIVES: We sought to study the relation between passive smoking at home and the risk of acute myocardial infarction (AMI). BACKGROUND: Previous epidemiologic studies have linked environmental tobacco smoke to an increased risk of coronary heart disease, but the evidence to support this view is not strong enough. To study this issue further, we analyzed the data from a case-control study conducted in Argentina between 1991 and 1994. METHODS: Case patients included 336 never-smokers with AMI. Control patients were 446 never-smokers admitted to the same network of hospitals with a wide spectrum of acute disorders unrelated to smoking or to known or suspected risk factors for AMI. Data on the smoking habits of the participants' close relatives (spouse and children) were collected by trained interviewers using a structured questionnaire. RESULTS: Compared with subjects whose relatives had never smoked, the multivariate odds ratios for passive smokers, according to the smoking status of their relatives, were 1.68 (95% confidence interval [CI] 1.20 to 2.37) for one or more relatives who smoked; 1.59 (95% CI 0.85 to 2.96) for a spouse who smoked; 1.24 (95% CI 0.61 to 2.52) for a spouse who smoked 1 to 20 cigarettes/day; 4.03 (95% CI 0.99 to 16.32) for a spouse who smoked >20 cigarettes/day; and 1.80 (95% CI 1.20 to 2.68) for one or more children who smoked. There was a significant interaction between passive smoking and hypercholesterolemia (> or = 240 mg/dl), hypertension, diabetes and family history of MI. CONCLUSIONS: In never-smokers, passive smoking at home appeared to be associated with the risk of AMI, and approximately 14% of cases in men and 18% of cases in women in this Argentinian cohort are attributable to passive smoking.