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Biomedical subjects

A E Becker

Publications and source records attributed to A E Becker.

At least 253 records · Page 14Linked to original sources
PubMed1977

Histologic changes in the normal aging aorta: implications for dissecting aortic aneurysm.

The histologic changes that occur in the media of the normal aorta at various ages were studied in 100 normal aortas. These changes encompassed (1) cystic medial necrosis, defined as pooling of mucoid material; (2) elastin fragmentation, characterized by disruption of elastin lamellae; (3) fibrosis, defined as an increase in collagen at the expense of smooth muscle cells; and (4) medionecrosis, defined as areas with apparent loss of nuclei. The changes showed a striking correlation with age and may represent the normal aging process for the aorta as determined histologically. The alterations showed a close relation in onset and location within the media, suggesting a phenomenon if injury and repair caused by hemodynamic events. These findings in the normal aging aorta reveal that none of the histologic changes observed can be regarded as the specific structural alteration responsible for the development of dissecting aneurysm.

Adolescent↗
PubMed1977

Pathogenesis of dissecting aneurysm of aorta. Comparative histopathologic study of significance of medial changes.

In previous investigation of the normal aging aorta, the claimed specificity of alterations in the media in the pathogenesis of dissecting aneurysm of the aorta was challenged. The concept was promoted that these changes are nonspecific and caused by general hemodynamic events within the aorta. In this investigation the aortic media was studied in patients with a dilated ascending aorta, whose hemodynamic profile is known to be altered. The results were compared with data obtained from the study of aortas with complete or incomplete dissection and aortas from patients with Marfan's syndrome, a condition known to predispose to dissection. Only quantitative differences were found between the normal "aging" aorta and the overtly abnormal aorta. The pathogenesis of dissected aneurysm, therefore, is considered to be initiated by processes if injury and repair within the aortic wall, consequent to hemodynamic forces. The histologic features of the media previously implicated as the specific underlying defect appear to represent the morphologic substrate of this traumatizing and reparative process. This process may gradually lead to dilatation of the aorta and, according to Laplace's law, a vicious cycle may ensue that may lead to further complications. Local circumstances determine whether a dilated aorta will rupture or whether an incomplete or complete dissection will occur. The fact that the aorta in patients with Marfan's syndrome shows basically the same structural alterations supports the concept proposed. The underlying connective tissue disorder in these patients will lead to complications at an earlier age. Dissecting aneurysm therefore is part of a spectrum of lesions that have as a common denominator the process of injury and repair.

Adolescent↗
PubMed1977

Atresia of the right atrioventricular orifice.

The results are reported of a study of 83 necropsied hearts with atresia of the right atrioventricular orifice. It is emphasised that right atrial or atrioventricular orificial atresia is a better term to describe this anomaly than "tricuspid atresia". Use of the latter term can be confusing when the morphologically tricuspid valve is located beneath the left atrium. It is accepted that the definition employed may include cases in which the mitral valve may be atretic, blocking normal exit from the right atrium, but it is argued that such cases would present clinically as "tricuspid atresia" and therefore are correctly designated as right atrial orificial atresia. The results show that the majority of hearts with right atrial orificial atresia have the ventricular morphology of primitive ventricle, most with, but a few without an outlet chamber. However, in a minority of hearts an imperforate membrane interposes between the right atrium and a formed but hypoplastic right ventricle. In two of the hearts, the imperforate membrane showed features of Ebstein's malformation. The hearts could be further subdivided according to the ventriculoarterial connection. Most had normally connected arteries (66 of 83), and all but 2 also had normal relations between the arteries; in these 2 hearts there was "anatomically corrected malposition". Twelve hearts showed transposition, one had double-outlet outlet chamber, and another persistent truncus arteriosus. The remaining 3 hearts, all without outlet chamber, had by definition a double outlet connection. A segmental approach provides the best way of classifying this anomaly, and an embryological explanation is offered for the variations in anatomy observed.

Aortic Valve Stenosis↗
PubMed1977

The left ventricle in congenital isolated pulmonary valve stenosis. A morphological study.

The wall thickness of the left ventricle was measured in the hearts of 16 children and 2 adults who died of congenital pulmonary valve stenosis. A right-to-left shunt through a patent foramen ovale had existed in 12 cases and was excluded in the other 6. The thickness of the left ventricular wall and the interventricular septum was increased in the majority of hearts, especially in the older patients. There was a good correlation between wall thickness and histological appearance of the left ventricular myocardium; in 2 cases there was also evidence of left ventricular myocardial fibrosis. The coronary arteries appeared normal in all cases. A direct interaction between the ventricles was thought to be a possible mechanism.

Adolescent↗
PubMed1977

What should we call the 'crista'?

Review of published work concerning congenital cardiac anomalies reveals that at least four different structures have been described as the crista supraventricular, in addition to the structure which in the normally formed right ventricle separates pulmonary and tricuspid valves. Possibility of further confusion arises since at least two different structures have been described under the name 'septal band'. We suggest that this potentially confusing situation will be best resolved by reserving the term 'crista' for description of the muscle mass between inflow and outflow portions of the right ventricle when there are no additional outflow tract anomalies. We then suggest that at least three separate structures warrant description in hearts with outflow tract anomalies. The first separates the semilunar valves, the second separates a semilunar valve from an atrioventricular valve, and the third is an extensive septal trabeculation of the right ventricle. Our suggested terms for these structures are the infundibular septum, ventriculo-infundibular fold, and trabecula septomarginalis, respectively. However, we believe that such terms would be better decided and agreed upon within an internationally formulated 'Nomina Cardiologica', a terminology as yet lacking in congenital heart disease.

Heart↗
PubMed1977

Minor congenital variations of cusp size in tricuspid aortic valves. Possible link with isolated aortic stenosis.

Clinically isolated aortic stenosis is most commonly caused by a congenitally malformed aortic valve. Many elderly patients with isolated aortic stenosis have a tricuspid aortic valve. It has been suggested in the past that inequalities in individual cusp size could be a factor leading to the development of the stenoses in these cases. In this study the width and height of individual aortic valve cusps were measured at necropsy in 200 hearts of patients without clinical signs of aortic stenosis, though the majority of valves obtained from elderly persons showed some ageing changes. The results were compared with similar measurements in 16 hearts of patients with clinically diagnosed and necropsy proven isolated aortic stenosis. The results show that inequality in cusp size is the rule rather than the exception. Indeed, only 5 of the 200 'normal' tricuspid aortic valves had 3 cusps of identical height and width, and each of the 16 cases with isolated aortic stenosis has cusps of differing size. The results seem to contradict the aforementioned hypothesis. However, the striking similarities between isolated aortic stenosis and the ageing aortic valve, suggest that isolated tricuspid aortic stenosis is an extreme with a spectrum of ageing alterations. Inequality in cusp size, with differences in mechanical tissue stress as a consequence, could then play a role in the pathogenesis of the stenosis by accelerating the ageing process.

Adolescent↗
PubMed1977

Location and size of acute transmural myocardial infarction estimated from thallium-201 scintiscans. A clinicopathological study.

A clinicopathological study was performed in 23 patients who died from acute transmural myocardial infarction and who had been studied with thallium-201 during the acute phase. Twenty patients died within five days and three later than five days after scintigraphy. The scintigraphic location and the estimated size of infarction in vivo were correlated with postmortem findings. There was good agreement in 91% between scintigraphic and postmortem location of infarction and in 70% between the ECG and postmortem findings. The size of infarction as determined from computer-processed schematic drawings of postmortem slices of the heart correlated well with the size determined from processed schematic drawings of the scintiscans (r = 0.91 for anterior infarction, r = 0.97 for inferior infarction, r = 0.86 for anterior-inferior infarction). It is concluded that thallium-201 scintigraphy provided more precise location of infarction than the ECG and that the size of the scintigraphically abnormal area reflected the extent of necrotic myocardium.

Humans↗
PubMed1977

Congenitally complete heart block. Developmental aspects.

Three cases of congenitally complete heart block are described of hearts in which other minor congenital malformations were not in themselves severe enough to disrupt the atrioventricular conduction system. The cases fitted well into the categorization of complete heart block suggested by Lev. Two exhibited lack of communication between the atrial and conducting tissues, the other had discontinuity of the penetrating atrioventricular bundle. In an attempt to explain why this discontinuity between different segments of the conducting tissues occurs, we re-examined several series of graded human embryos. This investigation suggested that the anulus fibrosus in the normal heart is derived from sulcus tissue of the atrioventricular junction, the endocardial atrioventricular cushions playing a minor role in the separation of atria from ventricles. The relationships between the sulcus tissues and the different components of the atrioventricular junctional area are discussed in terms of an explanation both for the existence of different types of congenitally complete heart block and for persistence of Mahaim (nodo-ventricular and nodo-fascicular) fibers.

Abnormalities, Multiple↗
PubMed1977

Spontaneous rupture of bicuspid aortic valve. An unusual cause of aortic insufficiency.

This report documents the clinicopathologic correlation between pure aortic regurgitation and an exceptional form of congenitally bicuspid aortic valve. The patient was known for many years to have mild aortic insufficiency. His condition suddenly deteriorated, with signs of an aggravated aortic regurgitation. Infectious endocarditis was considered, but the diagnosis was never established. Surgery revealed an exceptional form of a bicuspid aortic valve in which the conjoined cusp had prolapsed, due to rupture of a fibrous strand which previously had anchored the free rim of the cusp to the inner wall of the aorta. There were no signs of infectious endocarditis. It is suggested that spontaneous rupture of the cord caused the sudden aggravation of aortic regurgitation.

Aortic Rupture↗
PubMed1977

Specificity of cellular and myofibrillar disorientation in hypertrophic obstructive cardiomyopathy.

The specificity of the ultrastructural myocardial abnormalities in hypertrophic obstructive cardiomyopathy (HOCM) is undetermined. We undertook a quantitative study using myocardial biopsy specimens from the subaortic area in a patient with classical HOCM and compared them with hypertrophic left ventricular myocardium from a patient suffering from rheumatic valve disease. Myofibrillar disarray and side-to-side junctions were chosen as strictly quantifiable features. The former was seen as representing intracellular disorganization; the latter was seen as criterion for intercellular disorganization. The results showed that there is no preference for these abnormalities to occur in HOCM. Indeed, intracellular abnormalities more frequently occurred in the hypertrophic myocardium the patient without HOCM. Neither intracellular nor intercellular features can be regarded as specific for HOCM, even in a quantitative sense.

Adult↗
PubMed1976

Congenitally corrected transposition of the great arteries: morphologic study of 32 cases.

The detailed anatomy of the heart is described in 32 autopsy cases of congenitally corrected transposition of the great arteries.Tis condition is defined as the combination of atrioventricular (A-V) discordance and transposition of the great arteries. Examples of primitive (single) ventricle with "inverted" (that is, left-sided in situs solitus) outlet chamber are excluded. Six hearts with A-V discordance and pulmonary atresia are described in an appendix. In 29 cases of corrected transposition the heart was in situs solitus; in 3 it was in situs inversus totalis. Only 5 of these 32 hearts had no potential for intracardiac shunting. Anomalies of the tricuspid valve (91 percent of cases), ventricular septal defect (78 percent) and pulmonary outflow tract obstruction (44 percent) occurred with sufficient frequency to be considered part of the basic malformation and are described in detail. The precise anatomy and disposition of the A-V valve tension apparatus, the coronary arteries and the conducting tissues are described with special reference to possible surgical approaches for repair of the anomalies. In two hearts with situs solitus the aortic valve was right-sided with respect to the pulmonary valve. This finding is important for both diagnosis and nomenclature.

Autopsy↗
PubMed1976

Fat distribution in the adrenal cortex as an indication of the mode of intrauterine death.

The presence of fat in the fetal zone of the adrenal cortex in the stillborn macerated fetus is indicative of the mode of intrauterine death. Three basic patterns are recognized. In the type I pattern there is only a scant amount of fat, close to the medullary zone. In the type II pattern fat is more widespread and is present in many more cells of the fetal zone. The type III pattern reflects a massive fatty change of almost all cells throughout the fetal cortical zone. Correlation of the three fat patterns with the pathology of the placenta and clinical data relevant to the etiology of intrauterine death has led to the following conclusions. The type I fat pattern is indicative of an acute mode of death, the type II pattern is indicative of a more prolonged period of intrauterine deterioration prior to death, whereas the type III pattern is indicative of a chronic mode of death. Determination of the fat patterns in the fetal zone of the adrenal cortex can be helpful when the clinician is confronted with the problem of fetal death, especially when maceration may hamper more detailed pathologic studies.

Adrenal Cortex↗
PubMed1976

The sick sinus syndrome.

Clinical and electrophysiological characteristics have been investigated in a group of 30 patients with a sick sinus syndrome. No predictable response to exercise or drugs was observed, although a poor response of the sinus rate to atropine was present. Distal conduction abnormalities were found in seven of 14 patients, in whom detailed electrophysiological measurements were made, and sinus node recovery time was abnormal in all except one. Treatment with permanent pacing not only relieved syncope and dizziness, but made drug treatment of associated tachyarrhythmias feasible. The elusive and intermittent nature of the syndrome is stressed. The pathological findings in one case are described at length.

Age Factors↗
PubMed1976

Developing cardiac rupture as initial sign of acute myocardial infarction.

Pathological data are given of 4 patients in whom the development of cardiac rupture was the initial sign of myocardial infarction. The term 'concealed cardiac rupture' is proposed for this condition. In each instance the clinical diagnosis was 'onset of infarction', whereas the necropsy suggested that the acute onset of symptoms was caused by the start of rupture. The arguments for classifying the cases as 'concealed rupture' are (1) the lack of correlation between histological and clinical dating of the infarct, (2) the observation that the tear may take considerable time before actual epicardial breakthrough occurs, and (3) the fact that a high percentage of infarcts may pass clinically unnoticed.

Aged↗