Search PubMed⌕ Search

Biomedical subjects

S Y Ho

Publications and source records attributed to S Y Ho.

At least 289 records · Page 16Linked to original sources
PubMed1985

Influence of high dietary iron as ferrous carbonate and ferrous sulfate on iron metabolism in young calves.

Twelve intact male Holstein calves averaging 90 kg and 12 wk of age were fed one of three dietary treatments for 28 d. The diets were A) control, B) control plus 1000 ppm iron as ferrous carbonate, and C) control plus 1000 ppm iron as ferrous sulfate monohydrate. Calves were dosed orally on d 15 of the treatment period with 1 mCi of iron-59. Neither source of added iron had a significant effect on weight gains, feed consumption, hemoglobin, packed cell volume, serum total iron, serum total iron-binding capacity, unbound iron-binding capacity, serum copper, tissue copper, fecal dry matter, or a consistent effect on fecal pH. The ferrous carbonate had no significant effect on stable zinc or stable iron in any tissue studied. Calves fed ferrous sulfate had higher average stable iron in most tissues and significantly more in the small intestine. Tissue zinc was lower in spleen and pancreas of ferrous sulfate-fed calves. Both sources of added iron sharply reduced iron-59 in serum, whole blood, and body tissues. The reduction was substantially greater in calves fed the ferrous sulfate iron. Iron in ferrous sulfate had a higher biological availability than that in the ferrous carbonate; however, bioavailability of the ferrous carbonate iron appeared to be substantial and considerably more than that noted in previous studies in which a different source of ferrous carbonate was used. The maximum safe level of dietary iron is materially influenced by the source of iron with a higher tolerance indicated for ferrous carbonated than ferrous sulfate monohydrate.

Animal Feed↗
PubMed1984

Atrioventricular septal defect with intact atrial and ventricular septal structures.

A heart with an atrioventricular septal defect is characterized by absence of the atrioventricular muscular and membranous septa, a common atrioventricular junction, an unwedged position of the aortic valve annulus and disproportionate inlet--outlet dimensions of the ventricular septum. The clinical and post-mortem findings are described of a case which had intact atrial and ventricular septa but had all the other anatomical hallmarks of atrioventricular septal defect. The problems in clinical diagnosis may be overcome by cross-sectional echocardiography.

Cardiomegaly↗
PubMed1984

The surgical significance of the atrial branches of the coronary arteries.

The great number of open heart operations now performed via the right atrium, makes knowledge of the arrangement of the atrial arteries, particularly the sinus node artery, every important for the surgeon. Although studied by anatomists, little attention has been paid to the surgical significance of these arteries. We have therefore examined the distribution of the right atrial arteries and the course of the sinus node artery in 50 normal adult hearts by classic dissection following, in 30 cases, postmortem angiographic studies. Two major arteries of the right atrium were found to be nearly constant. The anterior artery was present in 96% of the cases and supplied the sinus node artery in 32 cases. Of most surgical significance was the lateral artery found in 90% of the cases. This lateral artery was the principal artery to the free atrial wall and in one case gave rise to the sinus node artery. The well-established preponderance of origin of the sinus node artery from the right coronary system (66%) as opposed to the left (30%) was confirmed. Infrequently, a double supply (4%) was seen. Variability was found in the course of the nodal artery relative to the cavoatrial junction - precaval (58%), retrocaval (36%) or encircling (6%).

Adult↗
PubMed1984

Malalignment of the interventricular septum with atrioventricular septal defect: its implications concerning conduction tissue disposition.

Malalignment of the interatrial and interventricular septal structures is rarely seen associated with atrioventricular septal defects. Such malalignment gives rise to an anomalous disposition of the conduction tissue specifically in regard to the siting of the atrioventricular node. Recognition of this abnormality prior to (or at) surgery is important if post-operative rhythm problems are to be avoided.

Abnormalities, Multiple↗
PubMed1984

Endocardial fibroelastosis and hypoplasia of the left ventricle in neonates without significant aortic stenosis.

Endocardial fibroelastosis in neonates with hypoplasia of the left ventricle is usually associated with severe aortic stenosis or atresia. In this study three hearts were examined, in which severe hypoplasia of the left ventricular cavity with myocardial hypertrophy and endocardial fibroelastosis were associated with small but non-stenotic subaortic outflow tracts and aortic valves. These features were contrasted with those of neonatal left heart hypoplasia in aortic stenosis and atresia. The index cases were examples of the very rare contracted form of endocardial fibroelastosis.

Aortic Valve↗
PubMed1984

Effects of high but nontoxic dietary manganese and iron on their metabolism by calves.

Sixteen male Holstein calves were fed one of four diets for 18 days in an experiment consisting of 0 and 1000 ppm supplemental manganese and 0 and 1000 ppm added iron as manganese carbonate and ferrous carbonate. The control diet contained 55 ppm manganese and 220 ppm iron. All calves were dosed orally 48 h prior to sacrifice with 500 muCi of manganese-54. Small intestinal iron was less in calves fed a high manganese diet, a possible interaction of these two elements at the absorption site. Feeding a high manganese diet tended to decrease iron (total) concentrations in liver and pancreas. When the high manganese diet was supplemented with additional iron, antagonistic effects of manganese on iron were eliminated. Neither iron nor manganese concentrations in tissues were affected by an increase of dietary iron. Manganese-54 content of tissue was reduced by the high manganese diet but was not affected by dietary iron. Total manganese and iron in feces fairly closely reflected dietary intake of each element with no evidence of interaction. Calves fed the high iron diet excreted less manganese-54 in their feces over 2 days. Total iron in blood serum was not affected significantly by the dietary treatments.

Animals↗
PubMed1984

Double-inlet ventricle: morphologic analysis and surgical implications in 32 cases.

We analyzed, using a sequential segmental approach, 32 cases of double-inlet ventricle to assess the feasibility of surgical "correction" by either ventricular septation or a modified Fontan procedure. Twenty-two hearts had two atrioventricular valves, connected to a left ventricle in 19, a right ventricle in two, and a solitary indeterminate ventricle in one. Septation was possible in only 13. In contrast, the Fontan procedure seemed feasible in 20. The remaining 10 specimens had double inlet via a common valve to the left ventricle in two, the right ventricle in six, and an indeterminate ventricle in two. Seven of these had right atrial isomerism. Ventricular septation was not considered a possibility in these hearts. The Fontan procedure combined with atrial septation was a possibility in seven cases. From the morphologic stance, although the modified Fontan procedure seemed suitable in most cases, a significant number of hearts with two atrioventricular valves were suitable for ventricular septation.

Endocardial Cushion Defects↗
PubMed1984

The surgical anatomy of hearts with no direct communication between the right atrium and the ventricular mass--so-called tricuspid atresia.

Seventy-six hearts were studied having no direct communication between the right atrium and the ventricular mass. The different cardiac chamber combinations producing so-called "tricuspid atresia" were considered. The nature of the atrioventricular valve atresia, the morphology of the ventricular mass, the size and position of the interventricular communication, the ventriculoarterial connection, and the presence of subarterial outflow tract obstruction were all analyzed. The majority of cases were of the "classical" type, i.e., absent right atrioventricular connection with the left atrium connected to the left ventricle. In another group there was absence of the right atrioventricular connection but the left atrium drained into the morphologically right ventricle, which was left-sided. In a third group both atrial chambers connected with the ventricular mass but some structure, an imperforate valve or muscular partition, completely blocked the flow pathway through the right side of the heart. All the hearts described are candidates for the Fontan procedure with either an atrioventricular or an atriopulmonary conduit. The surgical options would not be affected by the observed variability at the atrioventricular junction but would be dictated by the feasibility of incorporating the subpulmonary ventricle within the pulmonary circulation.

Heart Atria↗
PubMed1983

Double-inlet left ventricle with rudimentary right ventricle and ventriculoarterial concordance.

Seven hearts were studied that had in common the segmental combination of double-inlet left ventricle, rudimetary right ventricle and ventriculoarterial concordance. The prototype of these hearts has been described as the "Holmes heart" or "single ventricle type A1." Five of the hearts had 2 atrio-ventricular valves; in 1 of these the right valve was minimally straddling. The other 2 had a common valve. In 6 of the hearts the rudimentary right ventricle was obliquely situated on the anterior surface of the dominant left ventricle. The trabecular component was anterior and right-sided with the outlet components and pulmonary trunk in left-sided position. In the final case, both trabecular and outlet components of the rudimentary right ventricle were left-sided. Conduction tissue studies were performed in 2 hearts. In 1, the connecting atrioventricular node and bundle were in anomalous anterolateral position, as expected in double-inlet left ventricle. In the other, a ring-like, posterior, nonbranching bundle connected the regular node in the atrial septum to the branching bundle positioned on the anterior interventricular septum. The anatomic findings are related to the likely modes of presentation and differential diagnosis while the conduction tissue findings are discussed in the light of options for surgical repair. Thus, the term "single ventricle" is best avoided when describing hearts that unequivocally possess 2 ventricular chambers.

Heart Conduction System↗
PubMed1983

Aortopulmonary septal defect coexisting with ventricular septal defect and pulmonary atresia.

Three patients are described in whom an aortopulmonary septal defect (aortopulmonary window) coexisted with a ventricular septal defect and pulmonary atresia. One patient had mild and another, moderate aortic regurgitation. In addition, one patient had a sinus of Valsalva aortic aneurysm, while another had a single coronary artery arising from the pulmonary trunk. One patient underwent surgical correction in infancy; the other two, in early adult life. In all three patients, surgical correction involved closure of the aortopulmonary window, closure of the ventricular septal defect, and placement of a valved conduit between the right ventricle and the distal pulmonary trunk. One patient died 3 weeks postoperatively due to secondary hemorrhage where the conduit had been sutured to the right ventricle. The other two patients are alive and well 3 1/2 years and 6 months after surgery, respectively. The presence of aortopulmonary window permits normal development of the pulmonary arteries in the presence of the coexisting pulmonary atresia; in the three patients described, the absence of pulmonary vascular disease made total surgical repair feasible for this combination of defects.

Adult↗
PubMed1983

Interrupted aortic arch--anatomical features of surgical significance.

Analysis of 26 autopsy specimens with interruption of the aortic arch has led to a clearer understanding of the vital importance of associated cardiovascular abnormalities. In all cases there was an associated patent ductus arteriosus "supporting" the distal systemic circulation. "Proximal" septal defects, 22 ventricular septal defects and 3 aorto-pulmonary windows, were found in all but one specimen. The infundibular component of the ventricular septum was displaced posteriorly and leftward in 9 hearts resulting in significant left ventricular outflow obstruction in 8. In one specimen the infundibular septum was displaced anteriorly giving the effect of a "Fallot type" obstruction to the right ventricular outflow tract. Abnormal ventriculo-arterial connections were found in 7 hearts; 2 with discordant connection, 2 with double outlet, and 3 with single outlet of the heart. In 6 specimens there was an aberrant origin of the right subclavian from the distal aorta passing behind the esophagus to the right side. Various other arterial abnormalities were identified including a truncus arteriosus with separate but "transposed" origins of the pulmonary arteries. In short, in these hearts there were no examples of the rare situation where aortic arch interruption exists in isolation. This study therefore makes it very clear that a detailed understanding of associated anatomical abnormalities must accompany any attempt at surgical correction. Certainly in many of these cases management of the associated lesion will present more of a challenge than the difficult problem of dealing with the interrupted arch itself.

Abnormalities, Multiple↗
PubMed1983

Anatomical basis of cross sectional echocardiography.

Ten hearts were cut in planes to simulate echocardiographic cuts which may be taken to visualise the anatomy of the cardiac chambers and great arteries. The various myocardial wall segments were named from these sections by referring to their position in the reconstituted heart. The sections were studied in their correct anatomical position. In this way they provide a reference for appropriate orientation of echocardiographic images.

Echocardiography↗
PubMed1983

The surgical anatomy of the conduction tissues.

On the basis of our collective experience we have reviewed the disposition of the cardiac conduction tissues as they might be observed by the surgeon in both normal and abnormal hearts. The sinus node lies subepicardially in the terminal sulcus; because of its variable blood supply the entire superior cavoatrial junction is a potential danger area. There are no morphologically discrete tracts extending through the atrial tissues between sinus and atrioventricular nodes. The atrioventricular node, the atrial extent of the atrioventricular conduction axis, is contained exclusively within the triangle of Koch. The axis penetrates through the central fibrous body and branches on the muscular ventricular septum immediately beneath the interventricular component of the membranous septum. The landmarks to these structures are described as they might be seen through the right atrium, left atrium, and aorta. Consideration is then given to the surgical anatomy of the abnormal muscular atrioventricular connections that underscore the ventricular pre-excitation syndromes. Finally, rules are developed whereby the disposition of the conduction tissues can be predicted with accuracy in congenitally malformed hearts, in the settings of both normal and abnormal chamber connections. The most important variables in this respect are alignment between the atrial and ventricular septal structures and the pattern of ventricular architecture present.

Atrioventricular Node↗
PubMed1983

Aneurysm of the coronary sinus.

Two patients, an adult and a baby, with an aneurysm of the coronary sinus are described. This unusual anomaly was detected in the baby during angiographic investigations for congenital heart disease. The aneurysm was an unexpected postmortem finding in the adult. Although the adult died suddenly, there was no evidence that this could be linked to the presence of the aneurysm.

Adult↗