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Biomedical subjects

T A Seemayer

Publications and source records attributed to T A Seemayer.

18 recordsLinked to original sources
PubMed1979

Myxoid variant of malignant fibrous histiocytoma: ultrastructural observations.

The ultrastructural findings in 4 cases of the myxoid variant of malignant fibrous histiocytoma (MFH) are described. Although this neoplasm is characterized by a high rate of local recurrence, the overall prognosis is considerably better than the usual nonmyxoid MFH. The neoplasm is composed of an admixture of round, stellate and multinucleated giant cells within a myxoid and well-vascularized stroma. Electron microscopy demonstrated four principal cell types: a primitive mesenchymal cell, spindle cells of fibroblastic and histiocytic nature, and multinucleated giant cells. These observations complement the light microscopic features but probably are insufficient to differentiate critically this entity from other myxomatous lesions of mesenchymal soft tissue such as myxoma, pseudosarcomatous fasciitis, myxoid liposarcoma. The polymorphic cellular composition lends support to the concept that the neoplasm is probably derived from a primitive multipotent mesenchymal cell capable of structural and functional modulation toward more cytodifferentiated forms.

Diagnosis, Differential↗
PubMed1979

Myxoid liposarcoma. An electronmicroscopic study: biological and histogenetic considerations.

Ten myxoid liposarcomas (ML) were studied ultrastructurally in an attempt to determine the histogenesis of this neoplasm and structural associations which might contribute to their relatively benign clinical behavior. The findings were compared with normal and neoplastic adipose tissue. Three cell types were observed, i.e., "primitive" mesenchymal cells, intermediate cell types, and lipoblasts at various stages of development. The principle differences between the lipoblastic elements were the number and the size of intracytoplasmic fat vacuoles, the development of basement membrane-like material, micropinocytotic vesicles along the plasma membrane and the quantity and pleomorphism of mitochondria. The tumor vasculature was complex but consistently demonstrated a multilayered basal lamina. This finding has been described in neoplasms associated with a relatively good prognosis. This study demonstrates that the better differentiated lipoblasts in ML share some features with normal brown fetal fat and hibernoma. It is, thus, suggested that ML may be derived from brown adipose tissue.

Adipose Tissue, Brown↗
PubMed1979

Desmoplastic fibroma of bone. An ultrastructural study.

The ultrastructure of three cases of desmoplastic fibroma of bone is presented. The lesion is principally characterized by myofibroblasts admixed with lesser numbers of fibroblasts and primitive mesenchymal cells. Thus, the cellular composition is similar to that described in a variety of nonneoplastic proliferative processes of soft tissue. It is postulated that the myofibroblastic proliferation develops in response to unknown factors acting on marrow fibroblasts or primitive mesenchymal cells.

Adolescent↗
PubMed1979

Myofibroblasts in the stroma of invasive and metastatic carcinoma: a possible host response to neoplasia.

After observing the presence of numerous stromal myofibroblasts in scirrhous mammary carcinomas, a series of invasive and metastatic carcinomas from diverse sites was examined by electron microscopy to determine whether myofibroblasts might also be present in their stroma. Myofibroblasts were identified in each instance and were most abundant in neoplasms which were hard, sclerotic, and retracted. This finding suggests that myofibroblasts represent a component of the stromal reaction to many carcinomas and contribute to the desmoplasia and retraction which characterize many of these neoplasms. The host commands several responses to neoplasia. As a result of the expression of tumor-associated antigens, the immune system contributes lymphocytes, macrophages, and antibodies, a reflection of immunologic surveillance against neoplasia. In contrast to experimental systems tumor neoantigens are poorly expressed or even lacking in many human neoplasms; thus, the immune system may be weakly stimulated or not activated at all. Tumor neovascularization induced by a tumor-angiogenesis factor represents a second host response, possibly deleterious, for it may facilitate tumor dissemination. The stromal myofibroblast reaction to many invasive and metastatic carcinomas may constitute a third, albeit more primitive response. The density of collagen produced and contractile state of such tissue may signify an attempt by the host stroma to contain the neoplasm and impede vascular invasion. If so, myofibroblast induction may complement immune surveillance or constitute a separate mechanism of response to invasive neoplasia in man.

Carcinoma↗
PubMed1978

Renal failure secondary to angiomyolipoma. Case of Forme-Fruste tuberous sclerosis.

A fifty-four-year-old woman without the clinical features of tuberous sclerosis underwent nephrectomy at age thirty-three years for angiomyolipoma, and twenty-one years later severe renal failure developed. At necropsy the remaining kidney had extensive angiomyolipomatous involvement; not until the brain was examined was the diagnosis of tuberous sclerosis made. To date, this would appear to be the third case without clinical tuberous sclerosis in which renal involvement was the sole clinical expression of tuberous sclerosis, and the seventh reported instance of renal failure due to renal angiomyolipomatous hamartomatous transformation.

Female↗
PubMed1978

Thymic epithelial injury in graft-versus-host reactions following adrenalectomy.

In four separate experiments 140 adults A(H-2a) x C57BL/6(H-2b) F1hybrid mice were surgically adrenalectomized and divided into three experimental groups. Seventy-one additional adult F1hybrids (AXC57BL/6) which had not been adrenalectomized were divided into three similar groups. In Group 1 (GvH group), GvH reactions were induced by the injection of 50 x 106 pooled parental lymphoid cells intravenously. The second group (syngeneic group) received 50 x 106 pooled F1 hybrid lymphoid cells intravenously. The third group (uninoculated group) received no lymphoid inoculum. At regular intervals the animals were killed, autopsied, and histologically studied. Visceral alterations of GvH reaction were recorded in the thymus, lymph nodes, spleen, and liver in the GvH groups; none was present in the other groups. The thymuses in the nonadrenalectomized GvH group underwent prompt involution characterized by size reduction and cortical lymphoid cell depletion. These changes were not apparent in the GvH adrenalectomized group. Both GvH groups, however, demonstrated an effacement of the medulla, lymphocyte incursion into the medulla, lymphocyte emperipolesis of medullary epithelial cells, gradual disappearance of Hassall's corpuscles, epithelial cell injury, and an ingress of macrophages laden with nuclear and cellular debris. This study suggests that the stress and corticosteroid response which accompany a GvH reaction account for the reduction in the thymic size and cortical lymphoid cell mass. The medullary alterations, therefore, would appear to be initiated by the GvH reaction per se.

Adrenal Glands↗
PubMed1978

Bile acid conjugation in organ culture of human fetal liver.

An organ culture system for prolonged maintenance of human fetal liver has been developed and used to investigate the formation of bile acid conjugates. Multiple liver specimens were obtained from human abortuses and stillbirths ranging from 10 to 29 weeks of gestation. Within 3 hr of hysterotomy, small fragments of liver were established in organ culture. The morphological integrity of the explants was demonstrated by light and electron microscopy. Functional viability was determined by adding radiolabeled primary bile acid to the medium and assaying the taurine and glycine conjugates formed. Primary bile acid was taken up by the tissues, conjugated with taurine and glycine, and secreted into the medium at a constant rate during 10 days in vitro and in constant increments during a selected 24-hr period. The results establish that human fetal liver survives intact for periods up to 10 days in vitro. Taurine conjugates of the primary bile acids predominate throughout gestation and conjugates of cholic acid are synthesized in preference to those of chenodeoxycholic acid. Supplementation of the medium with taurine results in enhanced taurocholate formation with competitive inhibition of glycocholate synthesis, suggesting one acyl transferase system for both taurine and glycine. Finally, in medium supplemented with hydrocortisone there is a reversal of the glycine-taurine ratio seen in fetal liver.

Bile Acids and Salts↗
PubMed1977

Elastosis in benign sclerosing ductal proliferation of the female breast.

Elastosis, an abundance of elastic tissue, is commonly present in breast carcinoma. However, its diagnostic significance remaines an unsettled issue. This study documents 17 cases of elastosis occurring in a distinctive benign sclerosing ductal lesion of the female breast (Fenoglio and Lattes: Cancer 33: 691-700, 1974). Elastosis was characterized by staining reactions and, in several instances, by elastase digestion and electron microscopy. Yellow streaks and flecks may be apparent grossly and probably reflect the increased elastic tissue. Histologically, the lesion is generally stellate with central sclerosis and marked peripheral intraductal and ductular hyperplasia which is often papillary. Elastosis, which may be marked, is a constant finding and is predominantly periductal in location. It is emphasized that the gross and histologic features of the lesion may mimic carcinoma and that elastosis may be found in benign ductal lesions of the breast.

Adult↗
PubMed1977

Thymic involution in murine graft-versus-host reaction. Epithelial injury mimicking human thymic dysplasia.

Mild, moderate, and severe graft-versus-host (GVH) reactions were induced in four series of experiments in 71 CBA X A and C57BL/6 X A F1 hybrid mice. At regular intervals post-GVH reaction induction (Days 4-42), the animals were sacrificed, autopsied, and histologically studied. Visceral alterations of GVH reaction were recorded in the spleen, lymph nodes, liver, kidney, gut, and thymus. A spectrum of thymic changes was documented, ranging from obliteration of a definable cortex and medulla with loss of Hassall's corpuscles to marked involution with complete disappearance of the gland. Ultrastructural studies revealed damage to both lymphocytes and epithelial cells along with lymphocyte emperipolesis of epithelial cells, lymphocytolysis within epithelial cells, and accumulation of numerous autophagic vacuoles containing fragments of cellular debris within epithelial cells and histiocytes. The resemblance of these alterations to human thymic dysplasia as observed in primary immunodeficient conditions was striking. The theoretical implications of these studies for the pathogenesis of human congenital immunodeficiency states are considered.

Animals↗
PubMed1976

Giant cell carcinoma of the lung. A light and electron microscopic study.

Three cases of giant cell carcinoma of lung and six other lung carcinomas with large atypical cell formation were studied by both light and electron microscopy. The giant cell carcinomas showed unique light and electron microscopic features, whereas large atypical cells from other lung carcinomas usually retained some ultrastructural characteristics of their cellular origin. The giant cell carcinoma is characterized by abundant mitochondria, a concentric whorl of tonofilament-like fibrils, and aggregates of several pairs of centrioles. The "phagocytic activity" of the giant cell carcinoma is more likely attributable to the so-called tumor cell-tumor cell or leukocyte-tumor cell emperipolesis. Giant cell carcinoma of lung may originate from a primitive multipotential cell in the distal bronchiole or be associated with a squamous, glandular, or clear cell pattern. Whether in pure or mixed form, this tumor should still be considered a specific entity because of its unique light and electron microscopic features and the fulminant clinical course it follows despite rate reported exceptions.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1976

Endobronchial plasma cell granuloma (xanthomatous pseudotumor); a light and electron microscopic study.

Plasma cell granuloma (xanthomatous pseudotumor) is polymorphic at light as well as electron microscopic examination. At light microscopy the endobronchial variant of this entity was rich in plasma cells and interwoven, whorl-like, or concentrically arranged spindle cells. Foamy histiocytes and macrophages usually abundant in the intrapulmonary variant were rare. At electron microscopy particles 20 to 50 nm. in size were found at the bronchial mucosal surface but not elsewhere in the lesion. Plasma cells near the bronchial surface contained cytoplasmic fibrils, mitochondria with concentric cristae, and inclusions that bore a close resemblance to adjacent extracellular crystallized hemoglobin. Those in the center of the lesion ordinary round inclusions and none of the other changes. Spindle cells in the interlaced areas were mostly fibroblasts or myofibroblasts, whereas those whorled around capillaries resembled pericytes with basement membranes and nuxes-like intercellular junctions. Year rings like multilayered basal laminae were frequently present between the pericyte-like cells and the endothelial cells of the capillaries. The ultrastructure of plasma cell granuloma, like the histologic and clinical aspects, differs from that of sclerosing hemangioma, pseudolymphoma, and malignant plasma cell tumor affecting the lung.

Adult↗
PubMed1975

Peripheral nerve tumors involving paranasal sinuses: a case report and review of the literature.

A 45-year-old man, afflicted with von Recklinghausen's disease, with symptomatic schwannomas and plexiform neurofibromas involving the right maxillary antrum, a rare site for peripheral nerve tumors, is presented. After a literature review, 15 cases were considered adequate for a clinicopathologic study. Twelve schwannomas, 2 plexiform neurofibromas, 2 neurofibromas, and 1 probable malignant schwannoma were included. Epistaxis was common in tumors of the ethmoid sinus and nasal fossae, while pain was related to lesions of the maxillary sinus. Two benign schwannomas recurred and were cured by surgery alone. The importance of early diagnosis and thorough surgical excisions is emphasized, especially for those tumors associated with von Recklinghausen's disease. The difficulties involved in the diagnosis of primary malignant peripheral nerve tumors are discussed.

Adult↗
PubMed1975

The unique association of mammary stromal sarcoma with intraductal carcinoma.

The unique combination of clinically unsuspected stromal sarcoma and noninfiltrating intraductal mammary carcinoma is presented. This association has not been previously documented. The clinicopathologic features of cystosarcoma phyllodes and mammary stromal sarcoma are reviewed to provide background perspectives to illuminate the unusual aspects of this case.

Adult↗