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Biomedical subjects

R V Lucas

Publications and source records attributed to R V Lucas.

At least 19 recordsLinked to original sources
PubMed1996

Causes of sudden unexpected cardiac death in the first two decades of life.

Sudden, unexpected cardiac death in the age group 1 to 21 years usually is due to myocarditis, hypertrophic cardiomyopathy, aortic valvar stenosis, and coronary arterial abnormalities. The hearts of 70 patients <21 years of age who died suddenly were reviewed. Twenty patients were <1 year of age and 50 were 1 to 21 years old. The cardiac findings were compared with those in 68 age-matched controls with known cardiac disease who did not die suddenly. Significant cardiac abnormalities were present in 13 (65%) of the 20 infants; 10 (50%) had anomalies of the aortic origin of the coronary arteries. Among the 50 older patients, cardiac abnormalities were found in 40 (80%), among whom coronary arterial anomalies existed in 12 (24%). Anomalies of aortic origin more frequently involved the left main than the right coronary artery in both groups.

Adolescent↗
PubMed1990

Anisodamine increases blood flow to the retina-choroid and protects retinal and pancreatic cells against lipid peroxidation.

This study investigated the effect of anisodamine (2 and 5 mg/kg i.v.) on ocular and systemic blood flow distribution in awake lambs using the radioactive microsphere technique. In separate in vitro studies, the effects of anisodamine (at final concentrations of 0.01 to 2.5 mg/ml) were determined on arachidonic acid, alloxan and ultraviolet radiation-induced lipid peroxidation of isolated retinal cells from rabbits and on alloxan-induced lipid peroxidation of hamster pancreatic islet beta cells. Malondialdehyde production was used as an index of lipid peroxidation and measured by the thiobarbituric acid method. Anisodamine preferentially increased blood flow and oxygen delivery to the retina-choroid and iris-ciliary body of the eye by 50-100%. Anisodamine significantly attenuated lipid peroxidation in retinal cells induced by ultraviolet radiation, alloxan and arachidonic acid by 17-50% and protected pancreatic beta cells against alloxan-induced lipid peroxidation. These properties may, in part, account for the beneficial effect of anisodamine in certain patients with diabetes.

Alloxan↗
PubMed1989

Comparison of types of pulmonary stenosis with the state of the ventricular septum in complete transposition of the great arteries.

The pulmonary valve and left ventricular outflow tract of 214 hearts with d-transposition of the great arteries (d-TGA) were visually inspected (126 of 214 with intact ventricular septum and 88 of 214 with ventricular septal defect [VSD]). Pulmonary stenosis (PS), either valvular, subvalvular, or in combination, was present in 26 cases and was found to be more common in the presence of a VSD (20.5%) than intact ventricular septum (6.3%). PS occurred more commonly in the presence of a supracristal VSD than an infracristal VSD (70%, 7 of 10 vs 15%, 10 of 66). Further, infracristal or supracristal VSDs were associated with different types of pulmonary obstruction. In seven of ten cases with infracristal VSD and PS, the stenosis was caused by an anomaly of an atrioventricular valve. In six of seven cases with supracristal VSD and PS, the latter was caused by membranous encirclement of the left ventricular outflow tract.

Cardiomyopathy, Hypertrophic↗
PubMed1988

Gross and histologic anatomy of total anomalous pulmonary venous connections.

Among 49 heart specimens with total anomalous pulmonary venous connection (TAPVC), obstruction to pulmonary venous flow was present in all 13 cases with TAPVC below the diaphragm and in 53% of 36 cases with TAPVC above the diaphragm. Obstruction was produced by extrinsic pressures on the vein, intrinsic narrowing of the vein, or both. The histology of the narrowed veins was extremely variable, ranging from atrophy of the vein wall to hypertrophy of intima, media-adventitia, or both. Balloon dilation of narrowed veins was performed in 3 cases, without clinical or anatomic evidence of success.

Brachiocephalic Veins↗
PubMed1988

Formulary management at a tertiary-care facility: P&T committee interview.

Managing a formulary at a large tertiary-care center like the University of Minnesota Hospital and Clinic, demands a controlled, yet flexible system, Russell Lucas, MD, chairman of the P & T Committee, and Paul Abramowitz, PharmD, secretary of the P & T Committee tell Hospital Formulary in an exclusive interview. Because of their responsibility and commitment in educating the house officers who prescribe within their hospital, establishing P & T Committee guidelines and programs that are educational and nonconfrontational is critical. Discussed in this interview are the evolution of various subcommittees and adhoc groups (when greater expertise than that available on the P & T Committee was needed), the continuous development of educational programs, and the institution's policies on nonformulary drug requests and drug restrictions. Drs. Lucas and Abramowitz also comment on how HMOs, which account for nearly 50% of the health care provided in the area, may affect drug therapy practices within the University.

Drug Utilization↗
PubMed1987

Anatomic features of congenital pulmonary valvar stenosis.

A total of 31 specimens of hearts with congenital pulmonary valvar stenosis were studied. To define the anatomy of the normal pulmonary valve, 210 specimens of hearts considered to have a normal pulmonary valve were also reviewed. On the basis of gross morphology of the valve leaflets and annulus, the stenotic valves were subgrouped into domed, unicommissural, bicuspid, tricuspid, hypoplastic annulus, and dysplastic. The valve leaflets in all subgroups were thickened. The thickness varied in degree, but involved the entire length of the leaflet. Microscopically, the thickness in most cases was due to an increase in myxomatous tissue. In a few cases, the elastic and collagen components of the leaflet were increased. The valve annulus was abnormal in most cases. The abnormalities included replacement of the fibrous backbone of the annulus by myxomatous tissue and partial or complete absence of the annulus. The impact on valvar anatomy by direct surgical valvotomy (14 patients) and closed Brock valvotomy (two patients) was reviewed. Precise knowledge of pulmonary valve anatomy is an aid to successful balloon pulmonary valvuloplasty.

Adolescent↗
PubMed1987

Pulmonary arterial aneurysm. A pathologic study of five cases.

Five cases are described in which noninflammatory pulmonary arterial aneurysmal disease existed. In each case, severe pulmonary hypertension had been present. In one (woman, age 50 years), the pulmonary hypertension was of the primary type, while in each of the others, congenital heart disease was an underlying condition (atrial septal defect in three cases; each woman, age range 35 to 56 years) and complete transposition in the remaining case (boy, age ten). In one case with atrial septal defect, saccular aneurysm involving each major pulmonary arterial branch was considered to have resulted from atherosclerotic disease. In each of the remaining cases, cystic medial necrosis was present, and the aneurysmal disease was the result of laceration of a major pulmonary arterial segment. In one of the cases with atrial septal defect, the laceration was recent and extended through the full thickness of the pulmonary trunk in a circumferential manner. In the remaining three cases, lacerations were usually old and had not extended through the full thickness of the involved arterial segments. Saccular aneurysm formation (usually multiple) had resulted from weakness of the wall as a result of laceration and retraction of tissue.

Adult↗
PubMed1986

Scimitar syndrome in neonates: report of four cases and review of the literature.

Four neonates with scimitar syndrome are presented. Three of the cases had congenital cardiovascular abnormalities not usually regarded as part of the scimitar syndrome, namely, ventricular septal defect, abnormalities of the aortic arch, and abnormal relationship of the pulmonary arteries and bronchi. Review of the literature indicates that among subjects of all ages the incidence of additional congenital heart disease is 24%; in patients within the pediatric age group the incidence is about 36% and is highest (75%) among those subjects having diagnostic studies while neonates.

Bronchi↗
PubMed1986

Persistent truncus arteriosus: pathologic anatomy in 54 cases.

Fifty-four specimens of heart with persistent truncus arteriosus (PTA) were reviewed anatomically. According to the Collett-Edwards classification there were 28 examples of type I and 26 type II. The sex distribution was equal. The number of the truncal cusps ranged from one to four (42% tricuspid, 30% bicuspid, 24% quadricuspid, and 4% unicommissural). A unicommissural truncal valve has not been previously reported. In 72% of cases, the truncal valve leaflets were thickened or dysplastic. Two valves were stenotic. The truncus arteriosus originated from both ventricles equally in 42% of the cases, predominantly from the right ventricle in 42%, and predominantly from the left ventricle in 16% of the cases. In unoperated cases of PTA originating predominantly from the right ventricle, it appeared to us that usual operative correction might result in left ventricular outflow obstruction. Variations in coronary arterial origins and patterns were present in nearly half of the cases. A single coronary artery was observed in ten cases (18.5%). Stenosis of the ostium of one coronary artery was seen in each of four cases (7%). High posterior origin of the left coronary artery was observed in ten cases (18.5%). Among the associated cardiovascular anomalies, the most common were right aortic arch (36%) and interruption of the aortic arch (11%). Three cases with the latter condition exhibited crossed pulmonary arteries. Isolated cases with tricuspid atresia, vascular sling (left pulmonary artery arising from right pulmonary artery), and persistent common atrioventricular canal were encountered.

Adolescent↗
PubMed1986

Predictive value of lung biopsy in ventricular septal defect: long-term follow-up.

Although the Heath-Edwards classification has been used for more than 25 years to evaluate pulmonary vascular changes, its potential to predict the long-term course after successful ventricular septal defect closure has not been proved. Operative lung biopsy slides obtained at the time of closure from 57 infants and children who had been among the first survivors (between 1954 and 1960) of such surgery were graded in blinded fashion according to the Heath-Edwards classification system, and the resultant biopsy grade of each was compared with the eventual long-term outcome of each child. In 53 (93%) of the 57 cases, the Heath-Edwards system correlated well with long-term clinical or hemodynamic status of the patient. Grade IV changes were predictive of a usually fatal outcome, while grade I and II changes were generally benign. Death from pulmonary vascular disease occurred, however, in four children whose operative lung biopsy had been classified as either grade I or II, indicating that the focal nature of the higher Heath-Edwards grades, or human error, must be considered when this classification system is employed.

Adolescent↗
PubMed1986

Myoglobin facilitated oxygen diffusion maintains mechanical function of mammalian cardiac muscle.

Myoglobin, an intracellular iron containing protein that binds oxygen reversibly, has been shown in model systems to facilitate the diffusion of oxygen and thereby maintain the mechanical function of exercising canine skeletal muscle and of hypoxic benthic fish hearts. Since no such role has yet been established for mammalian cardiac muscle small diameter (less than or equal to 0.70 mm) isolated kitten papillary muscles were stimulated at 24 X min-1 under isometric conditions in a physiological bath maintained at 30 degrees C with an oxygen tension of approximately equal to 450 mm Hg (59.8 kPa) to obtain a level of oxygenation just adequate to meet the metabolic needs of the muscles, as confirmed experimentally. Myoglobin was inactivated by adding 2 X 10(-3) mol X litre-1 sodium nitrite to the bath to abolish the facilitated diffusion of oxygen in the presence or absence of glycolytic blockade by 10(-4) mol X litre-1 sodium iodoacetate. This resulted in a 22(8)% (with blockade) or 10(3)% (without blockade) decrease (p less than 0.05) in the maximal rate of relaxation (-dT/dtmax) of the papillary muscles. Since the depression in mechanical function was reversible by increasing the bath oxygen tension to approximately equal to 600 mm Hg (79.8 kPa) it is concluded that the myoglobin facilitated diffusion of oxygen plays a role in maintaining the mechanical function of mammalian cardiac muscle under normal conditions. Furthermore, the maximal rate of relaxation of cardiac muscle is a sensitive indicator of the presence of hypoxia.

Animals↗
PubMed1985

Transcatheter closure of patent ductus arteriosus in piglets.

To better determine the risks of transcatheter closure of a patent ductus arteriosus (PDA), a model of PDA was made in newborn piglets by using 5- to 7-mm angioplasty catheters to dilate the probe PDA. This maneuver resulted in a permanent PDA in most piglets. Four to 6 weeks later PDA closure was attempted using the Rashkind PDA occluder. Twelve such procedures were attempted, using clean but nonsterile technique. Nine of 12 PDAs were successfully closed. Two failures were the result of inability to successfully traverse the PDA. This problem was solved by using a long sheath to position the device properly. Four complications occurred, all related to device release: left pulmonary artery embolization in 1 case, femoral artery embolization in 1, torn pulmonic valve cusp in 1 and lodgment of a prosthesis on a pulmonic valve cusp. Two successfully implanted devices were infected at necropsy. This study demonstrates the value of a piglet model in testing transcatheter PDA occlusion devices, the importance of sterile technique in such procedures, the hazards of device retrieval through the right heart and the feasibility of transcatheter PDA closure.

Angioplasty, Balloon↗
PubMed1985

Morphologic changes in the pulmonary arteries after percutaneous balloon angioplasty for pulmonary arterial stenosis.

The pathologic appearance of pulmonary arteries subjected to balloon dilation was studied in four subjects with stenosis of pulmonary arteries. Nine vessels were dilated. Successful dilation in seven vessels was accompanied by intimal disruption and tearing of the media. In one vessel, at the site of a previous surgical procedure, dilation could not be accomplished. Histologically, this vessel was encased by reactive fibrous tissue, which may have precluded successful dilation. In one case, simultaneous rupture of the dilating balloon and the left pulmonary artery occurred. Morphologic examination could not adequately explain the cause of vessel rupture. Among the six vessels successfully dilated and studied 4 to 14 months after the dilation, the postdilation luminal diamter had been maintained. Tears in the intima and media as seen histologically had been filled in by scar tissue. In one artery a dilated segment distal to a residual obstruction revealed marked intimal proliferation.

Angioplasty, Balloon↗
PubMed1985

Ventricular trabeculations in the chick embryo heart and their contribution to ventricular and muscular septal development.

Sixty-two chick embryo hearts were studied at incremental stages of development (Hamburger-Hamilton stages 16 to 39) by scanning electron microscopy following 3% glutaraldehyde fixation and critical point drying. Early in cardiac development, the primitive ventricle becomes homogeneously trabeculated with highly organized sheets of myocytes lined by endocardial cells, with the trabeculae generally oriented in the dorsoventral direction. Coalescence of these trabecular sheets begins at stage 26, initially at the area of the bulboventricular flange, and later proceeding caudally toward the floor of the ventricle. The fusion process is finished by stage 30, resulting in a muscular ventricular septum that has now divided the primitive ventricle into right and left ventricles. Further growth of the ventricular septum is by continued fusion of the adjoining trabecular sheets. Remnants of the apposing trabecular sheets are found in the solidified muscular septum in the form of endocardial channels. We suggest that persistent patency of these channels results in muscular ventricular septal defects.

Animals↗
PubMed1984

Dilation angioplasty of congenital or operative narrowings of venous channels.

Balloon dilation angioplasty was attempted in 10 infants and children with severe congenital or operative "venous" obstructions. In five children the obstructions were "vena caval" and followed repair for transposition of the great vessels (four patients) or orthotopic liver transplantation (one patient). In the four patients with fixed vena caval or baffle obstructions, balloon angioplasty was successful in relieving the obstruction, decreasing the average gradient (16.0 to 4.5 mm Hg), and increasing the average diameter (3.0 to 8.9 mm) of the obstructed site. One child died 1 week later from an unrelated cerebral hemorrhage; the three survivors have had persistent clinical and angiographic improvement. The fifth child had severe systolic narrowing of the superior baffle limb caused by marked tricuspid regurgitation, which ballooned the superior limb of the baffle against the atrial roof. Angioplasty was unsuccessful in relieving this type of obstruction, which resolved with tricuspid valve replacement. Of the five infants with obstructed pulmonary veins, three had congenitally narrowed vessels associated with total anomalous pulmonary venous connection, one had acquired stenosis, and one had postoperative obstruction after repair of a mixed type of total anomalous pulmonary venous connection. Dilation was unsuccessful in all five patients, but for different reasons: in the congenitally narrowed veins, the waist in the balloon could not be eliminated, even with high dilating pressures; in the infant with acquired stenosis, the vein stretched but did not tear at low dilating pressures; and in the postoperative obstruction, angioplasty increased the diameter of the obstruction but did not increase flow to the affected lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1983

Isolated cleft mitral valve: a variety of congenital mitral regurgitation identified by 2-dimensional echocardiography.

Nine children with isolated cleft mitral valve, aged 1 day to 12 years, were studied. The electrocardiogram showed a normal QRS axis in 5 subjects. Cardiac catheterization was performed in 4 patients and demonstrated severe mitral insufficiency in 3 but failed to clearly demonstrate a cleft mitral valve or gooseneck deformity. The mitral cleft was confirmed at operation in 2 patients. Two-dimensional echocardiography demonstrated a cleft dividing the anterior mitral leaflet into 2 portions in each patient. The mitral anulus was normally positioned and the atrioventricular septum present. Atrial and ventricular septa were intact. Features similar to anatomic studies such as accessory chordae and thickening of the edges of the cleft with increasing age were also seen. Two-dimensional echocardiography is the only method available to reliably diagnose isolated cleft of the mitral valve.

Cardiac Catheterization↗