Preparation and characterization of collagen-elastin matrices from blood vessels intended as small diameter vascular grafts.

This study describes the selective removal of cell and cell residues from small and large diameter blood vessels for the preparation of tubular collagen:elastin matrices intended for small diameter vascular prosthesis. The results showed that total or partially devitalized collagen:elastin matrices may be conveniently prepared without denaturation of the collagen:elastin matrix with a high degree of preservation of the proteins. The efficiency of cell removal and the extent collagen and elastic fiber preservation were dependent on the segment and the type of blood vessel under study, with arteries characterized by a higher susceptibility of cell removal and better preservation of the collagen-elastin matrix.

Mapping of bovine pericardium: physical and histopathologic tests.

BACKGROUND AND AIMS OF THE STUDY: This study was performed to identify the physical and histopathologic characteristics of different sections of glutaraldehyde-tanned bovine pericardium. METHODS: Ten pericardial sacs were obtained from animals aged from 18 to 36 months. Physical tests included shrinkage and mechanical resistance (rupture, elongation, tenacity index). Collagen and elastic fibers were evaluated in Gomori's trichrome-stained sections, hematoxylin and eosin, by PAS and Verhoeff's method. Studied areas were proximal to the great arteries, and the right atrial, right ventricular, left ventricular and left atrial regions. RESULTS AND CONCLUSIONS: Results showed that bovine pericardium does not have enough regional differences to identify any single region for bioprosthesis manufacture. However, histopathology showed better preservation of collagen and elastic fibers in the right ventricular region, implying that this area is more adequate as bioprosthetic material.

Pathologic findings in 74 dysfunctional Braile-Biomédica bovine pericardial heart valves recovered at reoperation, 1978 to 1990.

This report describes the morphological data obtained from 74 Braile-Biomédica bovine pericardial valves (previously named IMC bovine pericardial valve) recovered at reoperation in our institution between 1978 and 1990. This retrospective analysis allowed for a thorough evaluation of the pathologic findings after long-term implantation of the Braile-Biomédica pericardial xenograft. The major cause of valve failure was pericardial tissue calcification, causing cuspal stiffening or structural defect responsible for clinical symptoms of stenosis and/or regurgitation. Our results demonstrated calcification in 65% of the explanted bioprostheses. Calcific deposits were most extensive in the tunica fibrosa of the pericardium, more prevalent in patients less than 30 years old at the time of implantation, and in valves implanted in the mitral position. Mild to moderate degenerative changes of the native pericardium were observed. No differences between men and women could be detected. Endocarditis was the second most frequent cause of xenograft failure (16%). Cuspal tears, contrasting with previous reports on the pathological features in clinically failed pericardial valves, were relatively infrequent (6.8%). Two valves explanted (2.7%) because clinical manifestation of valvular incompetence showed marked degenerative changes of the pericardial native tissue as the only findings. These observations, very similar to those reported for porcine aortic valves, complement and give support to previously published data on the satisfactory clinical performance of the Braile-Biomédica pericardial bioprosthesis. The discrepancy between the present observations and those reported by other authors on different types of pericardial valves, reinforces the opinion that these pericardial bioprostheses should not be studied as an unified group, the results and conclusions must be specific for each one of them.

[The functional expectations of valve bioprostheses. I. Physical and histopathological tests for the use of sections of bovine pericardium]. / Expectativa funcional de biopróteses valvulares. I. Testes físicos e histopatológicos para aproveitamento de regiões de pericárdio bovino.

PURPOSE: The heterogenicity of the bovine pericardium sac regarding its elasticity, extensibility and thickness encouraged the work with the purpose to study the different areas of pericardium, mapped according to its position on the heart. METHOD: Ten bovine pericardium sacs previously selected and obtained at the slaughterhouse immediately after the animal slaughter were utilized. The pericardia were sectioned sagittally from the anterior to the posterior portion, thus obtaining two parts, right and left. Two areas were demarcated for each one of them amounting to four regions: A, B, C and D. Each of the four regions was divided into two regions: 1 and 1, amounting to 80 samples. There have been physical tests (shrinkage and mechanical resistance), histopathological studies and statistical analysis were done. RESULTS: The right ventricle area (region D) had the best utilization (21.3%), and then the left ventricle area (region B, 16.2%). The physical tests on the utilized samples showed minimum and maximum values of 0.20 and 0.40 mm for the thickness, 2.0 and 7.0 kgf for force, 1.6 and 4.2 kgf/mm2 for rupture, 18 and 36% for stretching, 15 and 65 for tenacity index and 85 and 87 degrees C for shrinkage. The region D presented histologically and more preserved, either for the collagen fibers or the elastic ones. CONCLUSION: The results of the statistical analysis proved the need to increase the sample size to certify the existence of a sectioning of the pericardium and a more adequate position of the proof body (longitudinal, transversal and oblique) when obtaining the pericardium flap to make the valve bioprosthesis.

Experimental study of a biograft as aorto-aortic "bypass".

The authors present experimental results with a bovine "mammary" artery graft with a 6 months follow-up and histological study up to 3 months (Transmission and Scanning Electron Microscopy). They report a 100% patency in the 16 dogs operated on (there were 2 controls). Grafts used were 6 cm long, had a 4 mm diameter and were implanted as aorto-aortic bypass. Dinamic evolution of the pseudo-intima is described as thickening up to the 14th day, when it is "cleaned". These facts would be related with variation in the peripheral resistance and their objectives would be narrowing or widening the graft in order to accelerate or slow the flow speed, respectively. Factors related to Poiseuille's law (diameter, length, viscosity) are mentioned as important elements for the patency rate of long lengthened, thin-diametered grafts. Also, the electrical charge of the intima and the endothelial seeding are discussed.

Dynamic cardiomyoplasty in chronic Chagas' heart disease: clinicopathological data.

We report a 44-year-old man with chronic chagasic cardiomyopathy who underwent latissimus dorsi dynamic cardiomyoplasty and died 4 months later. The clinicopathological findings are discussed, and the literature is reviewed.

[Cardiac rhabdomyomas]. / Rabdomiomas cardíacos.

Case report of cardiac rhabdomyoma in one two days old infant with important cyanosis and respiratory insufficiency with evolution to death in few hours. The radiologic feature was a great enlargement of the heart and the electrocardiographic study showed left branch block. The two-dimensional echocardiography study showed multiple intracavitary tumours in both ventricles and in the right atrium. These features were confirmed in the post-mortem study. The microscopic study of the tumors showed proliferation of the spider cells, and vacuolation with the presence glycogen. The diagnosis of cardiac rhabdomyoma was confirmed. The brain and the kidney were not studied for the diagnosis of tuberous sclerosis or kidney tumors. It is very important the early diagnosis by echocardiography, due to the possibility of surgical resection of the intracavitary tumors that cause severe obstruction to the blood flow.

[Myocarditis simulating acute myocardial infarction. A case report]. / Miocardite simulando infarto agudo do miocárdio. Relato de caso.

A six month-old infant presenting congestive heart failure and electrocardiographic features of acute myocardial infarction, including increased CK-MB levels. The echocardiographic study showed normal origin of the coronary arteries and features compatible with myocardiopathy. After good early response to conventional therapy, the patient developed severe congestive heart failure and shock, and died. In the post-mortem study, the coronary arteries were previous. Microscopic study was compatible with acute myocarditis.

Tumor of the testicle: a case of melanotic neuroectodermal tumor of infancy.

We describe an 8-month-old boy with a tumor involving the right testicle and epididymis. Anatomical and pathological examination of this tumor revealed embryological tissue and melanin granules derived from the neural crest. This is an uncommon neoplasm, which is especially rare in the testicles. The patient was free of disease after 30 months.