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Biomedical subjects

A E Becker

Publications and source records attributed to A E Becker.

At least 199 records · Page 11Linked to original sources
PubMed1982

Myocardial disarray. A critical review.

Myocardial disarray or disorganisation is at present a contentious topic, not least because its value as a clinical marker for hypertrophic cardiomyopathy has changed considerably over the years. Initially observed as one of the features of asymmetric septal hypertrophy, disarray has since been promoted as its pathognomonic histological feature, regarded by some observers as the morphological manifestation of a genetically transmitted myocardial defect. Recently, however, it has become evident that myocardial disarray is not limited to hypertrophic cardiomyopathy, but is encountered in hearts with both congenital and acquired conditions, and is also observed in normal hearts. The specificity of disarray for hypertrophic cardiomyopathy is thus seriously questioned. Latterly, it has been suggested that disarray, judged from through-and-through sections of the ventricular midseptum is a highly specific and sensitive marker of hypertrophic cardiomyopathy when considered in quantitative rather than qualitative fashion. The present study sets out to answer the question whether disarray could be the histological expression of the normal but intricate fibre architecture of the heart, a consideration also initiated by debatable definitions of normality and abnormality of myocardial histology. Gross fibre dissections in five normal hearts showed that many sites occurred in which disarray was a natural phenomenon. In five more hearts it was found that the plane of section of a tissue block might profoundly influence the histology. In fact, tissue cubicles sampled from different faces showed a change in histology in the vast majority. Thus the diagnostic significance of myocardial disarray as a marker of hypertrophic cardiomyopathy in the clinical setting almost vanishes; a change in orientation of a tissue section may actually turn "normality" into "disarray".

Adolescent↗
PubMed1981

The internodal atrial myocardium.

The anatomical substrates of internodal conduction have long been a contentious topic. Debated first by the German Pathological Society in 1910, the consensus of established opinion for over half a century was that conduction between sinus and atrioventricular nodes occurred through plain myocardium. This was a conclusion supported by Truex in 1961. Despite his restatement of this fact in 1976, it has become fashionable to describe internodal conduction as being mediated by specialized internodal pathways. To reinvestigate this problem we studied 22 human fetal and 32 human infant hearts. In each case it was possible to cut the atrial tissues as a single block of tissue and to examine serial sections through the internodal myocardium. The sinus node, atrioventricular node, and segments of atrioventricular ring specialized tissue were recognized as specialized tissue using the light microscope in each heart. In contrast, there was nothing "special" about the myocardium between the nodes, nor was it possible to recognize tracts on the basis of either histological appearance or cellular architecture. It is concluded that, from the standpoint of light microscopy, there is no evidence whatsoever to support the purported concept of specialized anatomical substrates for internodal conduction.

Atrioventricular Node↗
PubMed1981

The Wolff-Parkinson-White syndrome and its anatomical substrates.

The anatomical substrates that underlie the clinical syndromes of preexcitation are still incompletely understood. Regarding the Wolff-Parkinson-White syndrome, there is increasing evidence that early ventricular activation is caused by accessory atrioventricular connections. These are muscular connections existing outside the specialized conduction tissue axis, which are almost always composed of working myocardial fibers. Left-sided accessory atrioventricular connections have been identified with most frequency. They occur in the presence of a well-developed fibrous annulus, thus contradicting the hypothesis that faulty development of the annulus is a necessary accompaniment. For right-sided and septal connections, this developmental concept may still hold, since there is marked variability in the formation of the right-sided annulus fibrosus. Even within these settings, however, the topography of accessory atrioventricular connections may vary considerably. Usually the accessory connection will pass on the epicardial aspect of the annulus fibrosus, particularly when left-sided. The connections are closely related to the fibrous annulus, but in other instances they may be in a superficial location. Multiple connections can occur in one heart. These anatomical features are of paramount significance for successful surgical ablation of accessory atrioventricular connections.

Heart Atria↗
PubMed1981

Ultrastructure of the normal human aortic media.

The ultrastructural organization of the adult human aortic media was studied utilizing aortic biopsies from 14 patients, ranging in age from 28 to 67, who underwent cardiac surgery. Apart from solid elastic elements the tissue spaces contained a vast amount of ill-defined thin streaks of elastin, an observation much facilitated by utilizing a selective elastin staining technique. In favorable sections, these streaks were found to be continuous

Adult↗
PubMed1981

Left ventricular fibre architecture in man.

In order to investigate the possibility of regional variation of ventricular structure, 25 normal postmortem human hearts were studied by inspection of cavity shape and subepicardial fibre orientation, by dissection, and by the histology of sections in two orthogonal planes. Ventricular architecture was complex. Inlet and outlet long axes were separated by 30 degrees in the left ventricle. In the right the corresponding figure was 90 degrees. The thickest part of the left ventricular wall was at the base. At the apex there was potential endo- and epicardial continuity. Left ventricular cavity shape departed significantly from any simple geometric figure, there being, consistently, regions of both positive and negative curvature on the diaphragmatic aspect. The presence of trabeculae caused considerable variation in wall thickness. Striking variation was found in the arrangement of subepicardial muscle fibres. Most pronounced was the contrast between the longitudinal arrangement of fibres observed on the oblique margin and the circumferential arrangement of those on the acute. On the diaphragmatic surface of the left ventricle, fibres near the crux and apex ran circumferentially while those between ran obliquely; those on the diaphragmatic surface of the right ventricle also ran circumferentially. Deeper in the myocardium the arrangement was simpler. In the mid-wall of the left ventricle fibres were circumferential, best developed towards the base and in the upper part of the septum. Near the apex of the left ventricle and in the mid-wall of the right ventricle such fibres were sparse. The subendocardial region consisted of longitudinally directed fibres forming the trabeculae and papillary muscles, while fibres deep to and between the trabeculae coursed more obliquely. These findings were confirmed by histology. Models based on uniform myocardial fibre structure cannot explain wall movement in normal subjects, and are likely to have significant limitations if used to investigated left ventricular function in disease.

Dissection↗
PubMed1981

Sudden death in a youth. A case of quadricuspid aortic valve with isolation of origin of left coronary artery.

A youth of 16 years of age died suddenly and quite unexpectedly while walking to school. The necropsy disclosed a quadricuspid aortic valve with complete isolation of the left coronary artery by an adherent aortic valve cusp. The left ventricular myocardium showed subendocardial contraction band necrosis suggesting that critical ischaemia had triggered a state of hypercontraction, in keeping with ventricular fibrillation as the immediate cause of death. The site of the anomaly in the aortic root showed dysplasia of the aortic wall and the affected valve cusp, histologically similar to the changes that characterise supravalvar aortic stenosis. The findings suggest a developmental anomaly, possibly a forme fruste of supravalvar aortic stenosis, rather than a postnatally acquired condition.

Adolescent↗
PubMed1981

Surgical anatomy of double-outlet right ventricle with situs solitus and atrioventricular concordance.

Sixty-three hearts with situs solitus, concordant atrioventricular connection, and more than half of both great arteries connected to the right ventricle have been studied to delineate their surgically important features. Specifically noted were the relationship of the arterial valves to each other and the type and position of the ventricular septal defect with special reference to the conduction tissue location. Infundibular morphology was ascertained and other congenital abnormalities were recorded. An estimate was made of the surgical options available given the various anatomic abnormalities present. The aorta was most commonly in the right posterior position but could be found anywhere in the arc extending to left anterior position. The septal defects were most frequently in subaortic position (34/65) and were usually of perimembranous type (45/65). Three hearts had two defects each and one heart had an intact ventricular septum. Identifying the type of defect was helpful in locating the conduction tissues. In addition, there were numerous associated anomalies, including 19 hearts with coronary artery malformations. Retrospective analysis of the surgical options suggested that 36% of the hearts would not have been operable during life. Approximately another third could have been corrected by use of an intraventricular tunnel from the ventricular septal defect to the aorta, and the remaining third would have needed more complex procedures. In the final analysis it was concluded that hearts with the ventriculoarterial connection of double-outlet right ventricle, though so varied as to preclude "standardization," did permit anatomic analysis and description in clear and consistent terms.

Coronary Vessels↗
PubMed1981

The importance of the apposition of the submucosal intestinal layers for primary wound healing of intestinal anastomosis.

This study was undertaken to examine the importance of the apposition of the submucosal layers in healing of the intestinal anastomosis. On 18 mongrel dogs, weighing between 8 and 15 kilograms, four anastomoses were performed on the small intestine. Two with a conventional anastomosis and two with rings of polyester-polyethyleneterephtalate, containing small Ticonal magnets. The force between the rings with the magnets varied from 0-3 newton between, respectively, 15 millimeters and zero millimeter distance. After three to four days, the rings cut through and disappeared from the anastomosis. Morphologic and microangiographic studies, undertaken at ten days, revealed that, in instances of good submucosal apposition, direct bridging of the defect in the submucosal layer was seen with rapid restoration of the villous epithelium and an undisturbed vascular pattern in the anastomotic area. This we called primary intestinal healing. In instances of bad submucosal apposition, we saw indirect bridging of the submucosal layer defect by smaller and longer strands of newly synthesized collagen tissue in the outer intestinal layers with a collateral circulation from the submucosal plexus to the arterial plexuses in these layers. In all instances, an epithelial defect still persisted at ten days. This type of wound healing we called secondary intestinal healing. The results showed that, with the magnetic rings, a significantly better apposition of the intestinal layers was achieved.

Animals↗
PubMed1980

Cardiac aneurysm complicated by Salmonella abscess. A clinicopathologic correlation in two patients.

Two patients have been documented in whom a preexisting left ventricular aneurysm became complicated by myocardial abscess. Presumptive clinical diagnoses of infected pulmonary infarction and recurrent myocardial infarction were made. In each instance the abscess was revealed at necropsy. Histologic studies suggested that the abscess had occurred through direct spread from an infectious mural endocarditis. This mechanism could be related to the nature of the inner coating, which in both instances revealed evidence of organizing thrombosis with incorporation into the wall of the aneurysms. The observations reemphasize the need to consider the possibility of an infectious cardiac complication in every patient who presents with puzzling and nondiagnostic symptoms but in whom signs of an infectious process are present.

Abscess↗