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Biomedical subjects

G W Moore

Publications and source records attributed to G W Moore.

At least 91 records · Page 5Linked to original sources
PubMed1986

The association of floppy mitral valve with disjunction of the mitral annulus fibrosus.

Floppy mitral valve is usually attributed to connective-tissue degeneration. However, we have observed several instances in which both a floppy mitral valve and an abnormal mitral annulus fibrosus were present at autopsy. To study this association, we examined 900 hearts (after postmortem arteriography and fixation in distention) from autopsies of adults at The Johns Hopkins Hospital. Twenty-five (3 percent) of the hearts had a morphologically typical floppy mitral valve; in 23 of them (92 percent), the mitral annulus fibrosus showed disjunction--i.e., a separation between the atrial wall-mitral valve junction and the left ventricular attachment. In 42 other hearts (5 percent), which were from significantly younger patients (mean age [+/- SE], 60 +/- 2 years vs. 68 +/- 3; P less than 0.05), there was mitral annulus disjunction but no floppy mitral valve. Two hearts had a floppy mitral valve but no disjunction of the annulus; both of them had old infarcts of the papillary muscle. Our results show that floppy mitral valve is significantly associated with disjunction of the mitral annulus fibrosus (P less than 0.001). We suggest that floppy mitral valve develops from hypermobility of the valve apparatus, and that it is usually secondary to disjunction of the mitral annulus fibrosus, an anatomic variation in the morphology of the annulus.

Age Factors↗
PubMed1986

Development of aortic and mitral valve continuity in the human embryonic heart.

The anatomic relationship of the aortic and mitral valves is a useful landmark in assessing congenital heart malformations. The atrioventricular and semilunar valve regions originate in widely separated parts of the early embryonic heart tube, and the process by which the normal fibrous continuity between the aortic and mitral valves is acquired has not been clearly defined. The development of the aortic and mitral valve relationship was studied in normal human embryos in the Carnegie Embryological Collection, and specimens of Carnegie stages 13, 15, 17, 19, and 23, prepared as serial histologic sections cut in the sagittal plane, were selected for reconstruction. In stage 13, the atrioventricular valve area is separated from the semilunar valve area by the large bend between the atrioventricular and outflow-tract components of the single lumen heart tube created by the left interventricular sulcus. In stages 15 and 17, the aortic valve rotates into a position near the atrioventricular valves with development of four chambers and a double circulation. In stage 19, there is fusion of aortic and mitral endocardial cushion material along the endocardial surface of the interventricular flange, and this relationship is maintained in subsequent stages. Determination of three-dimensional Cartesian coordinates of the midpoints of valve positions shows that, while there is growth of intervalvular distances up to stage 17, the aortic to mitral distance is essentially unchanged thereafter. During the period studied, the left ventricle increases in length over threefold. The relative lack of growth in the saddle-shaped fold between the atrioventricular and outflow tract components of the heart, contrasting with the rapid growth of the outwardly convex components of most of the atrial and ventricular walls, may be attributed to the different mechanical properties of the two configurations. It is postulated that the pathogenesis of congenital heart malformations, which characteristically have failure of development of aortic and mitral valve continuity, may involve abnormalities of rotation of the aortic region or malpositioning of the fold in the heart tube.

Aortic Valve↗
PubMed1986

Development of the atrioventricular valve region in the human embryo.

Severe cardiac malformations may involve the atrioventricular valve region, but the sequence of embryonic development of this important area has been little studied. In particular, the basis of atrioventricular muscular discontinuity, except at the conduction system, has remained unexplained. To examine this question, serial histologic sections of human embryos from the Carnegie Embryological Collection and from the Hopkins Pathology Collection were studied and six embryos were reconstructed. The atrioventricular sulcus can be identified in Carnegie stage 10 as an indentation or crease on the right side separating the heart tube from the umbilical vein. By stage 12 the sulcus has deepened and rotated anteriorly as the atria appear and the heart tube elongates rapidly within the confining pericardial space. Selective accumulation of cardiac jelly on the endocardial aspect of the constriction of the heart tube produced by the atrioventricular sulcus is pronounced by stage 14. By stage 16 the separation of the atrioventricular orifice into right and left components is well advanced, and by stage 18 the septation of the atria and ventricles is largely complete. The muscular connection between the atria and the ventricles becomes interrupted around most of the artioventricular sulcus, except for the His bundle, during the latter part of the embryonic period. The topography of the original sulcus assumes a catenoidal or saddle-shaped configuration, i.e., convex in one plane and concave in the perpendicular plane. The tension and pressure relationships in such a structure would favor cardiac jelly accumulation and the eventual disintegration of lines of myocyte connections passing across the groove. The preservation of the His bundle connection is explained by the failure of the sulcus to completely encircle the heart.

Heart↗
PubMed1986

Rotation of the junction of the outflow tract and great arteries in the embryonic human heart.

The factors which give rise to the normal relationship between the great arteries and their respective ventricles are unknown. The developmental anatomy of this region was studied by using frontal, sagittal, or transverse serial histologic sections of 17 normal human embryos of Carnegie stages 15-19 from the Carnegie Embryological Collection. Distances and angles between major anatomic landmarks were determined by using computer reconstructions of the serially sectioned embryos, three-dimensional analytic geometry, and Euclidean distance formulas. The findings show that between stages 15 and 19 there is a marked rotation of the axis of the semilunar valves: frontal 121 degrees counterclockwise, sagittal 196 degrees counterclockwise, and transverse 240 degrees clockwise. Simultaneously the great arteries lengthen at a faster rate than the rest of the heart; and there is also an increase in the caliber and wall thickness of the great arteries. These results suggest that the changing rate of growth between the great arteries and the heart is necessary to align the great arteries, the semilunar valves, and the muscular outflow tract septum appropriately with respect to the interventricular septum. Reductions in the rate of growth of the great arteries relative to the heart could, by causing changes in the rotation of great arteries and outflow tract septum, have a role in the pathogenesis of cardiovascular malformations such as tetralogy of Fallot and transposition of the great arteries.

Arteries↗
PubMed1986

Ventricular inversion and tricuspid atresia (VITA complex): long survival without surgical treatment.

Five patients with ventricular inversion, corrected transposition of the great arteries, and atresia of the left-sided atrioventricular (tricuspid) valve have been observed. Three patients died in infancy, two had large interatrial communications, one with an early stage of arterial-type hypertensive pulmonary vascular disease, and the third patient had a very small interatrial communication and severe cyanosis. The other two patients survived into adulthood; both had small interatrial communications, and one had severe venous-type hypertensive pulmonary vascular disease. The longer survival of the two patients is attributed to a balance between resistance and blood flow in the pulmonary circulation influenced by the size of the interatrial communication.

Adolescent↗
PubMed1986

Token swap test of significance for serial medical data bases.

Established tests of statistical significance are based upon the concept that observed data are drawn randomly from a larger, perhaps infinite source population. The significance value, p, is the probability that the observations are drawn from a source population satisfying the null hypothesis; if p is small enough (less than 5 percent, 1 percent, etc.), then the null hypothesis is rejected. Serial medical data bases, such as a hospital clinic intake or autopsy case accessions, often do not have an identifiable source population from which they are randomly drawn. In an effort to make a reasonable interpretation of these less-than-ideal data, this report introduces a "token swap" test of significance, in which the usual paradigm of repeated drawing from a source population is replaced by a paradigm or misclassification within the observed data themselves. The token swap test consists of rearranging the data into a balanced distribution, and determining the disparity between the observed and the balanced distribution of data. In a two-by-two contingency table, patients are represented as "tokens" distributed into four "cells." Significance is determined by the proportion of "token swaps" that are able to transform the balanced table into the observed table. The token swap test was applied to three series of autopsy observations, and gave results roughly comparable to the corresponding (two-tail) chi-square and one-tail Fisher exact tests. The token swap test of significance may be a useful alternative to classic statistical tests when the limiting assumptions of a retrospective, serial medical data base are present.

Computer-Assisted Instruction↗
PubMed1986

Automated translation of German to English medical text.

The feasibility of automated translation of scientific and medical documents remains controversial. This report describes a minicomputer-based German-to-English translation system (TRANSOFT) that employs word order rearrangement followed by word-for-word translation and disambiguation based on context. This translation system was applied to a computer-readable version of Adler's Knochenkrankheiten (Bone Diseases), which contains 118,604 words, with 10,216 distinct words in 7,211 sentences averaging 16.4 words each. The translation required 2,791 word rearrangement formulas, 78 percent of which were first used in the first half of the document. There were 2,392 occurrences of 12 potentially ambiguous terms, of which only 18 (0.8 percent) were not resolvable from the immediate context. As foreign language medical documents become increasingly available in computer-readable form through computerized typesetting, electronic publishing, and improved optical character recognition equipment, automated translation systems may provide a rapid and inexpensive means of obtaining draft translations.

Computers↗
PubMed1986

Multilingual translation techniques in the analysis of narrative medical text.

The feasibility of computer translation of scientific and medical documents is controversial. This report describes a minicomputer-based translation system (TRANSOFT) that employs word order rearrangement followed by word-for-word translation and resolution of ambiguities based on context. This translation system was applied to an entire medical textbook written in German and to short medical texts written in French, Italian, Spanish and Turkish. Results suggest the versatility of TRANSOFT for narrowly defined translation problems. As foreign language medical documents and medical records become increasingly available in computer readable form through word processing, computerized typesetting and hospital information systems, computer translation methods may provide a rapid and inexpensive means of obtaining draft translations.

Computers↗
PubMed1986

Temporal arteritis. A clinicopathologic study.

Clinical and laboratory findings of 237 consecutive patients who had 250 temporal artery biopsies performed at the Wilmer Institute during a 15-year period were reviewed. Biopsies were reviewed independently on three separate occasions by four observers who, unaware of the clinical history, made one of the following histopathologic diagnoses: active arteritis, healed arteritis, arteriosclerosis, atherosclerosis, normal, or other. Biopsies were reviewed a fourth time by the observers together to establish a consensus diagnosis. The frequency of intraobserver disagreement in biopsy interpretation ranged from 4.4 to 25.6% of cases. The frequency with which observers disagreed with the consensus diagnosis (interobserver variation) ranged from 4.3 to 13.5% of cases. Pre-biopsy steroid therapy for seven to eight weeks or longer was associated with loss of the histopathologic features of active arteritis. We recommend biopsies for all patients with known contraindications to steroid therapy. In addition, multivariant regression analysis suggests that certain patients can be selected who are likely to have positive biopsies. For some patients, the clinical diagnosis of temporal arteritis can be based on the clinical signs and symptoms and their response to a therapeutic trial of steroids.

Aged↗
PubMed1986

Metastatic behavior of rhabdomyosarcoma.

Embryonal and alveolar rhabdomyosarcoma probably have the same histogenesis, yet alveolar rhabdomyosarcoma has a considerably worse prognosis and is generally less responsive to treatment. The metastatic behavior of rhabdomyosarcoma in 22 autopsied subjects was analyzed with respect to the histologic subtypes of the tumors to determine whether the more aggressive behavior of alveolar rhabdomyosarcoma was related to greater tumor burden and/or more widely disseminated metastases. Subjects with embryonal rhabdomyosarcoma tended to survive longer and had greater numbers of metastatic sites at autopsy compared to subjects with alveolar rhabdomyosarcoma, but these differences were not statistically significant. In addition, there were no significant differences in the overall distribution of metastases between embryonal and alveolar rhabdomyosarcoma. The most frequent sites of metastases from both types of tumor were soft tissues (73%), serosal surfaces (64%), lymph nodes (64%), lungs (55%), and bone marrow (50%). The findings suggest that the metastatic behavior of rhabdomyosarcoma does not vary as a function of length of survival, mode of therapy, or histologic subtype. We propose that factors such as stage of disease at presentation and location of the primary tumor, rather than histologic subtype, are probably the most important variables governing the therapeutic responsiveness of rhabdomyosarcoma.

Adolescent↗
PubMed1986

Infarct expansion: pathologic analysis of 204 patients with a single myocardial infarct.

The reasons for the marked variability in expansion of myocardial infarcts are unknown. To examine this question, the hearts in 204 patients with a single myocardial infarct, autopsied at The Johns Hopkins Hospital and studied after coronary arteriography and fixation in distension, were reviewed. There were 58 (28%) hearts with marked infarct expansion, 34 (17%) with moderate expansion and 112 (55%) with no or minimal expansion. The degree of expansion was greater in larger, more transmural infarcts (p less than 0.001). Infarcts with greater expansion had significantly more endocardial thrombus (p less than 0.001) and endocardial fibroelastosis (p less than 0.01). Larger heart weight and degree of left ventricular hypertrophy had a significant negative correlation with infarct expansion (p less than 0.05). A markedly greater degree of expansion was noted in the 101 infarcts (50%) caused by lesions in the distribution of the left anterior descending coronary artery as compared with the 57 infarcts (28%) secondary to right coronary lesions and the 46 infarcts (23%) in the distribution of the left circumflex coronary artery (p less than 0.001). The results show that expansion is associated with large infarcts but is less marked in hearts with ventricular hypertrophy. Expansion occurs predominantly in infarcts in the left anterior descending coronary artery distribution, that is, regions of the left ventricular myocardium with the greatest curvature. These results suggest that the degree to which an infarct expands may be influenced by the preinfarction thickness of the ventricular wall.

Adult↗
PubMed1986

Arterial-venous relationships in the human left ventricular myocardium: anatomic basis for countercurrent regulation of blood flow.

The mechanism by which myocardial blood flow varies in response to metabolic demand is obscure. One hypothesis is a countercurrent regulation of arterial caliber by diffusible substances carried in venous blood. To study the anatomic basis for blood flow regulation, we performed combined arterial and venous injections in 20 human hearts and studied left ventricular intramyocardial vessels with radiography, 100 micron thick sections, and reconstructions of serial histologic sections. Penetrating arteries lie in interstitial spaces and are closely related to accompanying veins. These interstitial veins partially surround and are indented by branch arteries. A second system of veins lies within muscle fascicles between interstitial spaces and is not related to arteries. The isolated veins have collateral connections with interstitial veins and join them in the subepicardium. This vascular anatomy could allow arterial caliber to be regulated by diffusible substances carried in the interstitial veins. Arterial dilatation might prolong this effect by partial obstruction of interstitial veins, with the isolated venous system providing an alternative pathway for venous drainage and washout. The study shows that a vascular arrangement is present in human left ventricular myocardium that could provide a countercurrent regulation of blood flow with diffusible substances carried in venous blood.

Coronary Angiography↗
PubMed1986

Continuum of the thickness of surviving myocardial wall with single myocardial infarcts.

The pathologic correlate of the clinical terms subendocardial and transmural applied to myocardial infarcts is uncertain. To examine this question, we reviewed the morphology of 204 hearts with single myocardial infarcts studied at autopsy after coronary arteriography and fixation in distention. The thickness of surviving myocardium with the infarct (S) and the thickness of the adjacent noninfarcted myocardium (A) were measured microscopically and expressed as a ratio. The S:A ratios ranged from 0.00 to 0.83. Necrosis of the entire wall (S:A ratio = 0.00) was seen in 37 (18%) cases. Distribution of the remaining cases by 10% intervals of wall necrosis (ie, from 0.00 less than S:A ratio less than or equal to 0.10 through 0.90 less than S:A ratio less than or equal to 1.00) were present in 27, 33, 31, 24, 25, 12, 8, 6, 1, and 0 cases, respectively. A lower S:A ratio was correlated with infarct size, infarct expansion, infarct rupture, proximal location of the coronary artery lesion causing the infarct, recency of the infarct, and degree of endocardial mural thrombus. A higher S:A ratio was correlated with the degree of left ventricular hypertrophy. No correlation was observed between S:A ratio and several measures of coronary artery disease. Multivariate regression analysis showed that infarct expansion, infarct age, and rupture were distinct predictors of infarct thickness. The study shows that thickness of myocardium surviving with an infarct forms a continuum; there is no evidence of separate populations that would correspond to infarcts of transmural or subendocardial extent.

Adult↗
PubMed1986

Respiratory epithelial cell necrosis is the earliest lesion of hyaline membrane disease of the newborn.

The pathogenesis of hyaline membrane disease of the newborn remains controversial. In an attempt to identify early morphologic lesions of hyaline membrane disease, the authors reviewed the histologic sections of lung of all infants that survived for 12 hours or less and all stillborns on which autopsies had been performed at the Johns Hopkins Hospital between 1975 and 1983. Subjects showing more than trivial autolysis or with major congenital malformations were excluded from the study. Among the 70 live births included in this study, 10 (14%) surviving for 7-12 hours had typical hyaline membranes, which are composed of predominantly necrotic epithelial cells. Nine (13%) subjects surviving for 1-10 hours had hyaline membranes plus intraairway necrotic epithelial cell clumps, and 15 (21%) subjects surviving for 10 seconds to 4 hours had only intraairway necrotic epithelial cell clumps. Among the 44 stillborns, 3 (7%) had intraairway necrotic epithelial cell clumps, and 1 of them given resuscitation had hyaline membranes in addition. The results suggest that the initial lesion of hyaline membrane disease of the newborn is necrosis of respiratory epithelial cells, and that this process may begin before birth.

Autopsy↗