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Biomedical subjects

J L Titus

Publications and source records attributed to J L Titus.

At least 55 records · Page 3Linked to original sources
PubMed1981

Porcine heterograft valve replacement in carcinoid heart disease.

A 53-year-old man with a pancreatic carcinoid tumor and liver metastases had the carcinoid syndrome with involvement of the tricuspid valve by carcinoid plaque. The mitral valve was involved by unrelated myxomatous degeneration (floppy valve). Each valve was replaced by a Hancock glutaraldehyde-prepared porcine heterograft prosthesis. When the patient died of complications of the tumor 8 months postoperatively, both valves had clinically normal function. Nevertheless, the carcinoid plaque, which was present in all four cardiac chambers and almost completely covered the endocardial surfaces of both atria, extended onto both prostheses. This eventually might have interfered with prosthetic valve function.

Bioprosthesis↗
PubMed1978

Vectorcardiographic identification of myocardial scar: a discriminative study with automatically processed vectorcardiographic information.

A multivariate discriminative procedure for the vectorcardiographic identification of ischemic myocardial scarring was performed utilizing data from 1,162 vectorcardiograms (VCGs) obtained in clinically normal subjects and 90 VCGs obtained from patients proved at autopsy to have ischemic myocardial scars. The VCGs from patients with myocardial scars were divided into two groups, a design group of 50 cases and an evaluation group of 40 cases. The best vectorcardiographic variables to discriminate the clinically normal group from the design group with scars were identified by stepwise linear discrimination. Sixteen vectorcardiographic variables were then used for discriminative analysis. This analysis correctly identified myocardial scars in 45 of the 50 VCGs in the design group (sensitivity 90%); among the 1,162 VCGs from clinically normal subjects, 32 were misidentified as myocardial scar (specificity 97.2). The sensitivity of these defining criteria was then tested in the 40 cases of myocardial scar in the evaluation group and found to be reproducible; 34 of the 40 cases of this group (85.0%) were correctly identified as having a myocardial scar. The multivariate discriminative criteria developed in this study had greater sensitivity and specificity than standard methods usually employed in electrocardiography and vectorcardiography. The criteria defined need to be evaluated in a large series that includes instances of cardiac pathology of nonischemic nature.

Adolescent↗
PubMed1978

Myocardial abscesses.

A review of postmortem materials from two teaching hospitals, accumulated in a 14-year period (1962--1975), disclosed 63 patients with myocardial abscesses among 12,359 autopsies, an incidence of 0.5%. All 63 patients had multi-focal myocardial abscesses; the lesions were grossly discernible in six patients. Coexisting infective endocarditis was present in approximately 20% (12) of the 63 patients with myocardial abscesses. Candida and Staphylococcus aureus were most common organisms responsible for the abscesses. Candida was identified in 23 patients (37%) by histologic examination of the heart sections, and 11 of these also had antemortem blood cultures positive for Candida. Staphylococcus aureus was cultured from the antemortem blood of 22 patients, two of whom also showed candidal organisms in the heart at necropsy. Eighty-one per cent (51) of 63 patients had abscesses in one or more extracardiac organs. It appeared that most of the myocardial abscesses had resulted from disseminated sepsis. Surgical conditions, malignancy and alcoholic hepatic disease were the most frequent primary conditions in patients with myocardial abscesses.

Abscess↗
PubMed1977

Biosynthesis of type I and III collagens by cultured smooth muscle cells from human aorta.

The synthesis of collagen by human aortic smooth muscle cells was studied after incubating the cells with [3H]proline and [3H]glycine for 48 hr. The culture medium and cells were lyophilized and then digested with cyanogen bromide (CNBr) in 70% (wt/vol) formic acid. The resultant peptides were subjected to ion exchange chromatography on CM-cellulose and gel filtration on agarose. On the basis of the molar ratios of the alpha1(I)-CB8 and alpha1(III)-CB8 peptides of the alpha1(I) and alpha1(III) chains, approximately one quarter of the collagen synthesized by these cells was identified as type III and three quarters as type I. These data indicate that the smooth muscle can synthesize at least two types of collagen found in the arterial wall.

Aorta↗
PubMed1977

Cardiac rhabdomyoma simulating mitral atresia.

Clinical, catheterization, and pathologic findings were recorded in a newborn infant with tuberous sclerosis and multiple cardiac rhabdomyomas that produced a clinical picture simulating mitral atresia and the hypoplastic left-heart syndrome. The clinical picture was due to a left atrial tumor that completely obstructed the mitral valvular orifice. Even if the diagnosis of left atrial tumor had been made, successful surgical correction was unlikely because of left ventricular rhabdomyomas, which produced severe subvalvular aortic stenosis and did not appear to be resectable. This case demonstrates the possibility that a hamartoma, such as a rhabdomyoma, occasionally can mimic the hypoplastic left-heart syndrome.

Abnormalities, Multiple↗
PubMed1977

Nonbacterial thrombotic endocarditis (NBTE) and disseminated intravascular coagulation (DIC): autopsy study of 36 patients.

A pathogenetic relationship between nonbacterial thrombotic endocarditis (NBTE) and disseminated intravascular coagulation (DIC) was sought by reviewing autopsies from a recent 12-year period. Of 4,783 autopsies, 36 patients were found to have NBTE. The histopathologic diagnosis of DIC in patients with NBTE was dependent on the observation of thrombi in vasa recta and central glomerular capillaries of the kidneys and in sinusoids, arterioles, capillaries, venules, and medium-sized veins of the major viscera. Morphologic evidence of DIC was found in 18 (50%) of the 36 patients with NBTE. In addition, venous and arterial thromboses were found in 13 patients (36%) and pulmonary thromboembolism in 17 (47%). These findings support the view that NBTE and DIC may be pathogenetically related and result from a hypercoagulable state.

Adult↗
PubMed1976

Clinically unsuspected disseminated intravascular coagulation (DIC): an autopsy survey.

In a review of 768 consecutive autopsies, 21 (2.7%) clinically unsuspected cases of disseminated intravascular coagulation (DIC) syndrome were diagnosed by histologic examination. DIC was diagnosed by the presence of fibrin thrombi in arterioles, capillaries, venules, and medium-sized veins. Fibrin thrombi were found, in the descending order of frequency, in the brain, heart, lungs, kidneys, adrenals, spleen and liver. Most patients had multiple visceral involvement, with three showing fibrin thrombi in as many as ten organs. The density of fibrin thrombi was greatest in the spleen, followed by kidneys, liver, lungs, adrenals, brain, and heart. A review of clinical data showed that infections were the most common underlying conditions in 13 cases, including nine with positive bacterial cultures from blood or cerebrospinal fluid, or both. The results suggest that, despite increasing clinical recognition of DIC, a great number of patients remain unsuspected of having the DIC syndrome prior to postmortem examination.

Adolescent↗
PubMed1976

Stenotic semilunar valve in persistent truncus arteriosus.

The clinical, hemodynamic, and pathologic findings in two newborn infants with persistent truncus arteriosus and stenosis of the truncal valve are described. In one case the anatomic features of the basic condition were classic, with a dysplastic semilunar valve which was mainly stenotic and also incompetent, while in the other the truncus arteriosus arose exclusively from the right ventricle and was almost exclusively stenotic. A ventricular septal defect was the only outlet for the left ventricle. In this case, mitral stenosis was also present and associated with a left-to-right shunt at the atrial level.

Aortic Valve Stenosis↗
PubMed1975

Juvenile temporal arteritis. Biopsy study of four cases.

Two young adults (aged 21 and 22 years) and two children (aged 7 and 8 years) complained of an unsightly, soft, painless unilateral nodule in the temporal region, ranging from 0.5 to 1.5 cm in diameter, clinically diagnosed as lipoma, sebaceous cyst, or dermoid cyst. In each instance, the patient had no evidence of systemic disease or history of trauma, and the nodule was excised for cosmetic reasons. Histologic examination of the lesions showed non-giant-cell granulomatous inflammation of the temporal arteries with intimal proliferation and microaneurysmal disruption of the media. Whether the lesions represent a juvenile form of temporal arteritis, an unusual form of localized polyarteritis nodosa, or Kimura disease (subcutaneous angiolymphoid hyperplasia with eosinophilia) remains conjectural.

Adult↗
PubMed1975

Time course and zonal variations of ischemia-induced myocardial cationic electrolyte derangements.

Myocardial cationic electrolytes were determined at regular time intervals up to 24 hours after coronary artery ligation in the dog. Replicate electrolyte ratios were computed for different areas of the heart at each time interval. For purposes of statistical analysis, ratios from two border areas and four areas remote from the infarct were pooled as values for ZONE B and ZONE N, respectively, and compared with those from the infarct proper, ZONE I. Ischemia-induced tissue Mg++/Ca++ changes paralleled those of K+/Na+ with respect to time course and zonal variations. In ZONE I, both K+/Na+ and Mg++/Ca++ fell precipitously during the first hour, and the falls became more gradual thereafter, approac hing those of extracellular fluid at 24 hours. Changes in ZONE B, which appeared normal histologically, followed a similar downward trend but differed in magnitude from those in ZONE I (P smaller than 0.01). Changes in ZONE N were small but did not always overlap values in sham-operated dogs. It was concluded that lowered tissue K+/Na+ and Mg++/Ca++ were sensitive, but not specific, indices of myocardial ishemia, and multiple samplings of ionic ratios were essential for proper interpretation of ischemia-induced myocardial electrolyte derangements.

Animals↗
PubMed1975

Motion of the tricuspid valve annulus in anesthetized intact dogs.

Phasic variations in the size, position, and geometry of the tricuspid valve annulus during the cardiac cycle were studied in five normal anethetized dogs 2-6 weeks after 8-11 lead beads had been sutured on the endocardial surface of the valve ring during cardiopulmonary bypass. Field-by-field measurements from biplane videoangiograms were used to assess changes in valve ring size and shape during control hemodynamic conditions and during increased heart rates. In addition, the percutaneous production of a complete atrioventricular block in two dogs enabled us to observe the effect of isolated atrial contractions on the valve annulus. During normal sinus rhythm, progressive narrowing of the annulus during atrial and ventricular contractions reduced its area by 20-39% of the maximal valve circumference during diastole; approximately two-thirds of the total ring narrowing was associated with atrial systole. These findings suggest that one of the functions of atrial contraction is the reduction in size of the atrioventricular valve orifices prior to the onset of ventricular systole.

Anesthesia, General↗
PubMed1975

Macroscopic enzyme-mapping verification of large, homogeneous, experimental myocardial infarcts of predictable size and location in dogs.

Difficulty is frequently experienced in producing a large homogeneous myocardial infarct in the dog heart because of the extensive network of coronary anastomoses. This problem may be overcome by combining the ligation of the left anterior descending coronary artery with agar injection into the distal coronary vasculature to obliterate anastomotic channels. All infarcts produced in this manner occupied a constant area in the anterior wall of the left ventricle. From our results in 25 dogs, the individual infarct averaged 12.3 Gm. in weight (range 9.4 to 13.5), representing 25 to 30 per cent of the total left ventricular muscle mass. The homogeneity of the infarct was verified by a simple, macroscopic enzyme-mapping technique based on the inability of the ischemic (dehydrogenase-deficient) myocardium to reduce triphenyl tetrazolium chloride and by detailed histologic studies. Apart from providing ample raw material for comprehensive morphologic, chemical, histochemical, and radioisotopic analyses, a large myocardial infarct also serves as a useful experimental model for various physiological and hemodynamic studies of cardiogenic shock and left ventricular akinesis.

Agar↗
PubMed1975

Anatomy and histology of aorta of White Carneau pigeon.

On the basis of anatomical and histologic studies, four distinct zones of the aorta of the atherosclerosis-prone White Carneau pigeon were defined. From its origin to about 1 cm. above the level of the celiac artery (the elastic zone), the aorta had a media composed of alternating lamellae of smooth muscle cells and fibroblasts with elastic plates between them. Distal to the elastic zone was the transitional zone, which was about 1 cm. long and ended at the level of the celiac artery. At this level there was an intimal cushion of longitudinally arranged smooth muscle cells that was present at birth but increased in thickness with age; an occasional lymphocyte-like cell was also present in the cushion. Typically, the atherosclerotic lesion originated in the smooth muscle cell cushion. In the transitional zone the media had an elastic architecture in the lateral third, the remainder being predominantly muscular. The segment of aorta from the celiac artery to the ischiadic arteries (hybrid zone) had a hybrid architecture with a thick muscular anterior wall and a thin elastic posterior wall. The structure distal to the ischiadic arteries was purely muscular (muscular zone). The presence of intimal smooth muscle cells in the transitional zone at birth, in the precise location where the "classic" atherosclerotic lesion develops months later, suggests that atherosclerosis develops within preexisting smooth muscle cell cushions which apparently represent a normal histologic feature of this area.

Age Factors↗