Anastomosis of bypass grafts using a low-powered CO2 laser.

The purpose of this study was to evaluate the feasibility of using a low-powered CO2 laser to perform end-to-side anastomoses of bypass grafts. The internal jugular veins of 13 domestic swine were removed and used as grafts to bypass their ligated carotid arteries. Each end of the vein graft was apposed to the artery with four to six temporary stay sutures, and a waveguide delivery CO2 laser with a power density of 900 mW/mm2 was used to perform the anastomoses, after which the sutures were removed. The animals were sacrificed postoperatively at five time intervals: 2 to 4 hours, 5 days, 1 month, 3 months, and 5 months. Of the 10 anastomoses studied at 2 to 4 hours, 70% were fully patent, none thrombosed, and 30% disrupted. Of the 16 anastomoses studied between 5 days and 5 months postoperatively, 88% were patent, 12% thrombosed, and none disrupted. None of the animals developed aneurysms at any stage of this investigation. Histologic analysis of acute studies revealed thermal damage such as charring of tissue, unraveling of the collagen fibrils, and the formation of microvacuoles. Within 3 months, the anastomotic sites showed localized healing with intimal fibromuscular proliferation and dense fibrous tissue. Good apposition of tissue was found to be of great importance in achieving patency of vessels in this procedure.

Microcystic adenoma (serous cystadenoma) of the pancreas. A study of 14 cases with immunohistochemical and electron-microscopic correlation.

Microcystic adenoma (serous cystadenoma) of the pancreas (MA) is an unusual benign tumor of uncertain histogenesis. We have studied 14 cases of MA from 11 women and three men. The average age at diagnosis was 64 years. Six tumors were discovered incidentally. Tumors varied from 2.5 to 12 cm in greatest dimension and all were multicystic; eight tumors were located in the pancreatic head, two in the body, and three in the tail. Each tumor was composed of variably sized cysts lined by simple cuboidal or flattened, focally glycogen-rich epithelium. The stroma was variably collagenized and showed highly vascularized, delicate to broad fibrous septae, which focally contained dystrophic calcification, cholesterol clefts, and hemosiderin. Immunohistochemical studies were performed on eight cases to determine the cell of origin. Epithelial membrane antigen and a low-molecular-weight keratin, detected by monoclonal antibodies PKK1 or AE1/AE3, were diffusely seen in tumor cells of all cases. Tumor cells were uniformly negative for carcinoembryonic antigen, chromogranin, insulin, glucagon, somatostatin, vasoactive intestinal peptide, pancreatic polypeptide, and a low-molecular-weight keratin detected by monoclonal antibody PKK2. Tumor cell antigen reactivity most resembled that seen in normal centroacinar and ductal cells. Electron microscopy of seven cases showed primitive tumor cells with irregularly spaced, short, blunt microvilli, luminal occluding junctions and belt desmosomes, bundles of filaments including dense bodies in both apical and basal cell cytoplasm, sparse organelles, and variable but often pronounced amounts of glycogen. These ultrastructural features most closely resembled the normal pancreatic centroacinar cell. Based on both immunohistochemical and ultrastructural features described above, we conclude that the centroacinar cell is the cell of origin of MA.

Chloroquine-induced cardiomyopathy.

Biventricular hypertrophy and failure developed in two patients during treatment of systemic lupus erythematosus with chloroquine phosphate. In both patients, morphologic analysis of the myocardium, obtained by a right ventricular endomyocardial biopsy in one patient and at autopsy in the other, revealed accumulations of electron-dense concentric and parallel lamellae and curvilinear bodies within cardiac myocytes. These deposits were similar to those reported in chloroquine-induced skeletal myopathy and were considered to represent evidence of chloroquine-induced cardiotoxicity rather than a cardiovascular manifestation of the underlying disease. Clinical awareness and an endomyocardial biopsy specimen are necessary for the appropriate diagnosis of chloroquine-induced cardiomyopathy.

Rare primary sarcomas of the heart.

Three patients with primary malignant cardiac neoplasms are described. All tumors were intracavitary myxomatous masses of the left atrium. Preoperative clinical diagnostic techniques did not indicate malignancy, but suggested mitral stenosis, cor triatriatum, and cardiac myxoma. Grossly, the tumors were sessile rather than pedunculated, and they invaded the underlying structures. Microscopically, although the tumors resembled benign cardiac myxomas, they exhibited mitotic activity and areas of necroses. Ultrastructural examination revealed a spectrum of differentiated mesenchymal cells that lacked the maturation features of cardiac myxoma cells. These gross, microscopic, and ultrastructural features, which suggested the tumors' malignant potential, should help in the early recognition and management of similar tumors.

Sarcomatous type of malignant mesothelioma.

Thirteen malignant mesotheliomas of a sarcomatous type were studied by light microscopy and ten were studied by electron microscopy. The histologic patterns varied from tumor to tumor, often resembling other soft tissue sarcomas. Electron microscopic observation showed most of the tumors to be composed of primitive cells. Despite their mesenchymal character, many tumors contained foci of rudimentary epithelial differentiation. It is concluded that both histologic types of malignant mesothelioma, the epithelial as well as the sarcomatous, originate from the same precursor cell at various points of its differentiation and reflect the range of maturation from the mesenchymal reserve cell to the epithelial mesothelial cell.

Multilocular cystic leiomyoma of the kidney.

A large, multilocular cystic mass from the kidney of a 26-year-old woman was examined by light microscopy and transmission electron microscopy. Ultrastructurally the cysts were shown to be lined by smooth muscle cells, giving evidence that the cysts originated in smooth muscle. Thus the tumor is considered to be a multilocular cystic leiomyoma, an apparently unique renal tumor.

Calcification in chronically-implanted blood pumps: experimental results and review of the literature.

Blood compatibility is a major objective in the development of long-term, implantable circulatory assist (left ventricular assist devices) and replacement (total artificial heart) devices. An important problem in experimental studies in animals has been the propensity for calcification to occur at the blood/material interface. Presented is a summary of our experience (27 studies) with blood pump calcification and a review of the current literature regarding this complication.

Persistent atrial paralysis: Case report with light microscopy and ultrastructural analyses.

Persistent atrial paralysis in a patient with complete heart block and mild mitral insufficiency is presented. Left atrial specimens obtained during implantation of a permanent cardiac pulse generator showed evidence of hypertrophy and fibrosis; subcellular degenerative changes ranged from near normal to irreversible, thus suggesting that atrial paralysis may be due to the replacement of normal atrial muscle with nonfunctional fibrous tissue.

Ultrastructural analysis of human penile corpus cavernosum. Its significance in tumescence and detumescence.

The erectile tissue from 15 normal and impotent male patients was studied by electron microscopy to determine if any ultrastructural features could contribute to the basic understanding of the physiology of penile erection and detumescence. It was found that the endothelium lining the cavernous lacunae contained both contractile elements and Weibel-Palade bodies which have a possible role in vasoconstriction. Within the trabeculae of the cavernous body there was an abundance of elastin as well as oxytalan and elaunin fibers around bundles of smooth muscle. With these elements affording an anchorage system for contraction of smooth muscles within the trabeculae, an alternate contraction of smooth muscles and endothelium could account for the erectile and detumescent states.

Ultrastructure of endometrial stromal foam cells.

An endometrium with cystic-glandular hyperplasia contained large foam cells in the stroma. The majority had ultrastructural characteristics of endometrial stromal cells, although a few were interpreted as macrophages. Endometrial stromal cells that appeared normal by light microscopy contained varying quantities of lipid on ultrastructural examination, and differed from the predominate type of foam cell only by having less cytoplasmic volume and maintaining an elongated shape. Cells intermediate in size and shape between normal stromal cells and foam cells further substantiated the origin of most of the foam cells from endometrial stroma.

A method for enumeration ot T and B lymphocytes in tissues.

A method for the identification of T and B lymphocytes in tissue specimens is described. A sonication technique results in viable relatively pure lymphocyte populations which are easily classified by their surface markers. This readily reproducible method can become a standard laboratory procedure in the evaluation of disease states which require such information related to the classification of lymphocyte cell origin.

ULTRASTRUCTURAL ANALYSES OF STONE HEART SYNDROME AT ONSET AND SIX DAYS LATER FOLLOWING TOTAL SUPPORT OF THE CIRCULATION WITH A PARTIAL ARTIFICIAL HEART OR LEFT VENTRICULAR ASSIST DEVICE (ALVAD).

Ischemic myocardial contracture developed in a 21-year-old man following aortic and mitral valve replacement. The patient's circulation was supported totally for 6 days with an abdominal left ventricular assist device (ALVAD). Cardiac allografting was then undertaken. Samples of myocardium taken at the original operation and 6 days later at transplantation were analyzed ultrastructurally. At the onset of ischemic cortracture, left ventricular abnormalities included hypercontraction of myofibrils, loss of normal A-band and Z-band patterns, mitochondrial swelling with fusion of cristae, interfibrillar edema and glycogen depletion. Capillaries demonstrated swelling of endothelial cells and basement membrane disruption. Six days later, ultrastructural morphology showed further degeneration. The myofibrils remained hypercontracted, but were more fragmented. Degenerative changes in mitochondria were more advanced and calcium deposition in cristae was present. No glycogen was seen. The right ventricular myocardium exhibited significantly fewer ultrastructural abnormalities. The principal right ventricular changes were endothelial swelling and basement membrane disruption. Glycogen granules were present. Ischemic contracture affects the left ventricle more than the right, and the morphology becomes more abnormal with time. To our knowledge, this is the first instance wherein morphologic progressions of the ultrastructural alterations of ischemic contracture have been documented.