Utilizing the atrioventricular and semilunar valves as ultrasonic landmarks, a simple reproducible technic is described for the ultrasonic evaluation of the heart and its great vessels in the normal neonate. The importance of the clinical application of this method is discussed.
Echocardiographic studies were performed on 240 normal newborns. Qualitative assessment was made of the interrelationships of the pulmonary, aortic, tricuspid, and mitral valves, and of interventricular septal motion. Quantitative norms were obtained for the following parameters: amplitude of motion of anterior leaflets of tricuspid and mitral valves, anteroposterior diameter of the ventricular and left atrial cavities, thickness of ventricular walls and interventricular septum, outside diameter of aortic and pulmonary roots, and interaortic and interpulmonary cusp distances.
The natriuretic peptides (NP) are a group of structurally similar but genetically distinct peptides with many favorable physiological properties that have emerged as important candidates for development of diagnostic tools and therapeutic agents in cardiovascular diseases. The NP family includes atrial natriuretic peptide (ANP, 28AA), urodilatin (INN: Ularitide, 32 AA), B-type natriuretic peptide (BNP, 32AA), C-type natriuretic peptide (CNP, 22AA), and D-type natriuretic peptide (DNP, 38AA). They share common features and exhibit tissue distribution of gene expression as well as functional and pharmacological characteristics. The primary sites of synthesis of the NP are the heart and brain; additional extra cardiac and extra cranial sites include intestine and kidney. Membrane-bound guanyl cyclase-coupled NP receptors (NPR) (A- and B- types) are generally implicated in mediating NP effects via the production of cyclic GMP as the intracellular messenger. NPR-C lacking the guanyl cyclase domain may influence the target cell function through inhibitory guanine nucleotide (Gi) protein, and they likely also act as clearance receptors for circulating peptides. NPs are identified as regulatory diuretic-natriuretic substances responsible for salt and water homeostasis and as hormones lowering blood pressure. This review discusses the essential biochemistry, physiological properties of NP and their manifold functional implications in cardiovascular medicine.
The natriuretic peptides (NP) appear to be functional by midgestation, respond to volume stimuli, and regulate blood pressure and salt and water balance in the developing embryo. In addition, the NP may help regulate the blood supply to the fetus, acting as vasodilators in the placental vasculature. Peaks of ANP and BNP expression during gestation coincide with significant events in cardiac organogenesis, suggesting a role for NP in the formation of the heart. Levels of atrial natriuretic peptide (ANP) are higher in the fetal circulation than in adults, and fetal ventricles express higher levels of ANP and B-type natriuretic peptide (BNP) than adult ventricles. In this comprehensive review we have discussed the role NP during development of the fetal heart and circulation and in various cardiovascular diseases of neonatal and pediatric age group.
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