Ovid Technologies (Wolters Kluwer Health)
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Desmin Mutation Responsible for Idiopathic Dilated Cardiomyopathy
Background
—Idiopathic dilated cardiomyopathy, of which ≈20% of cases are familial (FDCM), is a primary myocardial disorder characterized by ventricular dilatation and impaired systolic function. It is a common cause of heart failure and the need for cardiac transplantation. Although 6 chromosomal loci responsible for autosomal dominant FDCM have been mapped by linkage analysis, none of these genes have been identified. By use of the candidate-gene approach, actin was identified recently as being responsible for dilated cardiomyopathy. Considerable evidence suggests desmin, a muscle-specific intermediate filament, plays a significant role in cardiac growth and development.
Methods and Results
—To determine whether a defect of desmin induces dilated cardiomyopathy, 44 probands with FDCM underwent clinical evaluation and DNA analysis. Diagnostic criteria, detected by echocardiography, consisted of ventricular dimension of ≥2.7 cm/m
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with an ejection fraction ≤50% in the absence of other potential causes. After amplification by polymerase chain reaction, the exons of the desmin gene were sequenced. A missense desmin mutation, Ile451Met, which cosegregates with FDCM without clinically evident skeletal muscle abnormalities, was identified in a 4-generation family but was not detected in 460 unrelated healthy individuals.
Conclusions
—A novel missense mutation of desmin, Ile451Met, was identified as the genetic cause of idiopathic dilated cardiomyopathy. This finding is of particular significance because this is the first mutation detected in the desmin tail domain, and the function of the desmin tail remains unknown. Because this mutation leads to a restricted cardiac phenotype in the family studied in the present report, it suggests that the tail of desmin plays an important functional role in cardiac tissue.
Ovid Technologies (Wolters Kluwer Health) - Tập 100 Số 5 - Trang 461-464 - 1999
Life and Death of Cardiac Stem Cells
Ovid Technologies (Wolters Kluwer Health) - Tập 113 Số 11 - Trang 1451-1463 - 2006
Contemporary Definitions and Classification of the Cardiomyopathies Classifications of heart muscle diseases have proved to be exceedingly complex and in many respects contradictory. Indeed, the precise language used to describe these diseases is profoundly important. A new contemporary and rigorous classification of cardiomyopathies (with definitions) is proposed here. This reference document affords an important framework and measure of clarity to this heterogeneous group of diseases. Of particular note, the present classification scheme recognizes the rapid evolution of molecular genetics in cardiology, as well as the introduction of several recently described diseases, and is unique in that it incorporates ion channelopathies as a primary cardiomyopathy.
Ovid Technologies (Wolters Kluwer Health) - Tập 113 Số 14 - Trang 1807-1816 - 2006
Clinical Approach to Genetic Cardiomyopathy in Children
Background
Cardiomyopathy (CM) remains one of the leading cardiac causes of death in children, although in the majority of cases, the cause is unknown. To have an impact on morbidity and mortality, attention must shift to etiology-specific treatments. The diagnostic evaluation of children with CM of genetic origin is complicated by the large number of rare genetic causes, the broad range of clinical presentations, and the array of specialized diagnostic tests and biochemical assays.
Methods and Results
We present a multidisciplinary diagnostic approach to pediatric CM of genetic etiology. We specify criteria for abnormal left ventricular systolic performance and structure that suggest CM based on established normal echocardiographic measurements and list other indications to consider an evaluation for CM. We provide a differential diagnosis of genetic conditions associated with CM, classified as inborn errors of metabolism, malformation syndromes, neuromuscular diseases, and familial isolated CM disorders. A diagnostic strategy is offered that is based on the clinical presentation: biochemical abnormalities, encephalopathy, dysmorphic features or multiple malformations, neuromuscular disease, apparently isolated CM, and pathological specimen findings. Adjunctive treatment measures are recommended for severely ill patients in whom a metabolic cause of CM is suspected. A protocol is provided for the evaluation of moribund patients.
Conclusions
In summary, we hope to assist pediatric cardiologists and other subspecialists in the evaluation of children with CM for a possible genetic cause using a presentation-based approach. This should increase the percentage of children with CM for whom a diagnosis can be established, with important implications for treatment, prognosis, and genetic counseling.
Ovid Technologies (Wolters Kluwer Health) - Tập 94 Số 8 - Trang 2021-2038 - 1996
Function of Cardiac Receptors Stimulation of right and left atrial receptors causes an increase in activity in sympathetic nerves [see table in the PDF file] to the sinoatrial node resulting in 1) an increase in heart rate, 2) a decrease in activity in nerves to the kidney, with an unknown effect, and 3) a diuresis caused by a blood-borne agent which is said by others to be a reduction in the concentration of antidiuretic hormone.
This exciting finding leaves us with many questions both pure and applied. One may be important to us now. Remembering that these receptors have been vividly demonstrated in the atria of man should we not ask, Are these two small chambers not more important in man than commonly appreciated?
Ovid Technologies (Wolters Kluwer Health) - Tập 48 Số 3 - Trang 463-480 - 1973
Tilt Test for Investigating a Neural Component in Hypertension Hemodynamic changes associated with diastolic hypertension were investigated using 50° head-up for 52 untreated hypertensive patients not in cardiac failure, and for 17 normotensive subjects. Normals responded to tilt with±10 mm Hg change in mean arterial pressure. Twenty-four hypertensives responded similarly; the remainder had either orthostatic hypertension (18) or orthostatic hypotension (10). During tilt, cardiac output reduction of each hypertensive group was greater than normal, but only orthostatic hypertensives responded with exaggerated increase in peripheral resistance. When supine, orthostatic hypotensives had lower cardiac indices and higher peripheral resistances than orthostatic hypertensives. When the three hypertensive groups were compared with respect to clinical features, orthostatic hypertensives had the least severe vascular disease; orthostatic hypotensives were the opposite extreme, and normal responders were intermediate. These findings suggest that neurogenic activity is highest in mild hypertension and in the more severe forms of the disease, it is least.
Ovid Technologies (Wolters Kluwer Health) - Tập 36 Số 3 - Trang 387-393 - 1967
Reflex vasodilation induced by coronary angiography in human subjects. In order to evaluate the reflex peripheral vascular effects of coronary arteriography, forearm blood flow was measured plethysmographically and forearm vascular resistance calculated before and during coronary angiography with Hypaque-M, 75%, and Renografin-76. The injection of Hypaque into the left coronary artery resulted in a forearm vasodilation which could not be duplicated by an injection of a comparable amount of contrast into the ascending aorta, three centimeters above the coronary ostia. Forearm blood flow rose from 2.95 to 5.41 ml/min/100 ml (83.4%) and forearm vascular resistance fell from 35.8 to 19.9 mm Hg/ml/min/100 ml (44.4%). Renografin injected into the left coronary artery resulted in less forearm vasodilation (21% increase in forearm blood flow and 32% decrease in forearm vascular resistance). When coronary arteriography was repeated following injection of atropine into the brachial artery, no forearm vasodilation occurred. It is suggested that in human subjects myocardial or coronary artery receptors can be activated by the intracoronary injection of iodinated contrast media which results in a forearm vasodilation.
Ovid Technologies (Wolters Kluwer Health) - Tập 53 Số 3 - Trang 490-493 - 1976
Role of the Capacitance and Resistance Vessels in Vasovagal Syncope Withdrawal of sympathetic tone to the veins resulting in peripheral pooling of blood has been suggested as an important factor contributing to the decrease in cardiac output and hence arterial pressure that occurs during vasovagal syncope. However, no measurements of venous tone during syncope have been reported. In the course of other studies on the circulatory effects of negative pressure below the iliac crests, and 80° head-up tilt, vasovagal reactions occurred in 10 subjects. Heart rate, central venous pressure, arterial pressure, forearm blood flow, forearm vascular resistance, and forearm or hand venous tone were measured. The typical vasovagal reaction could be divided into two phases. A gradual fall in arterial pressure signified the onset of phase I, during which forearm vascular resistance did not change significantly. The duration of phase I was highly variable. The onset of phase II was denoted by an abrupt fall in arterial pressure and heart rate and a decrease of 62% in forearm vascular resistance, from 36 to 14 mm Hg/ml/100 g/min. However, venoconstriction rather than venodilatation occurred in the forearm or hand veins. Since central venous pressure did not change prior to or during the onset of the reaction, it is unlikely that venodilatation occurred in other vascular beds. It is concluded that two of the major mechanisms responsible for the hypotension of vasovagal syncope initiated by orthostasis or lower body negative pressure are bradycardia and dilatation of the resistance vessels. In contrast, it appears that the venous bed, by constricting, tends to maintain filling pressure and thereby cardiac output, and thus works in an opposite direction.
Ovid Technologies (Wolters Kluwer Health) - Tập 37 Số 4 - Trang 524-533 - 1968
Gastric dilation during stimulation of cardiac sensory receptors.
Ovid Technologies (Wolters Kluwer Health) - Tập 63 Số 4 - Trang 960-964 - 1981
Abnormal Aortic Valve Development in Mice Lacking Endothelial Nitric Oxide Synthase
Background
—Endothelium-derived nitric oxide (NO) is produced by an oxidative reaction catalyzed by endothelial NO synthase (eNOS). NO plays a crucial role in controlling cell growth and apoptosis, as well as having well-characterized vasodilator and antithrombotic actions. More recently, endothelium-derived NO was shown to be involved in postdevelopmental vascular remodeling and angiogenesis, as well as in the formation of limb vasculature during embryogenesis. Therefore, we investigated the role of endothelium-derived NO during cardiovascular development using mice deficient in eNOS.
Methods and Results
—We examined the hearts of 12 mature eNOS-deficient and 26 mature wild-type mice. Five of the mature eNOS-deficient mice had a bicuspid aortic valve; none of the 26 wild-type animals exhibited identifiable valvular or cardiac abnormalities. Immunohistochemical analysis revealed prominent eNOS expression localized to the endothelium lining the valve cusps of the aorta in mature wild-type mice; expression was localized to the myocardium and endothelial cell monolayer lining the valve leaflets in the developing embryo.
Conclusions
—These results show a strong association between eNOS deficiency and the presence of a bicuspid aortic valve; they provide the first molecular insight into one of the most common types of congenital cardiac abnormality.
Ovid Technologies (Wolters Kluwer Health) - Tập 101 Số 20 - Trang 2345-2348 - 2000
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