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Query: UMLS:C1261473 (sarcoma)
 25,952 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The v-vis gene encodes p28sis, the transforming protein of simian sarcoma virus. This gene resulted from a fusion of the env gene of simian sarcoma-associated virus and the woolly monkey gene for the B chain of platelet-derived growth factor (PDGF). Previous work has shown that the v-sis gene product undergoes signal sequence cleavage, glycosylation, dimerization, and proteolytic processing to yield a secreted form of the protein. It transport across the endoplasmic reticulum is blocked by the introduction of a charged amino acid residue within the signal sequence, the protein does not dimerize, is not secreted, and is no longer transforming as assayed by focus-forming ability in NIH 3T3 cells. Instead, this mutant protein localizes to the nucleus as demonstrated by both indirect immunofluorescence and cell fractionation. Using a series of deletion mutations, we delimited an amino acid sequence within this protein which is responsible for nuclear localization. This region is completely conserved in the predicted human c-sis protein, although it lies outside of regions required for transformation by the v-sis gene product. This nuclear transport signal is contained within amino acid residues 237 to 255, RVTIRTVRVRRPPKGKHRK. An amino acid sequence containing these residues is capable of directing cytoplasmic v-sis mutant proteins to the nucleus. This sequence is also capable of directing less efficient nuclear transport of a normally cytoplasmic protein, pyruvate kinase. Pulse-chase experiments indicate that the half-lives of nuclear and cytoplasmic v-sis mutant proteins are approximately 35 min. Using the heat-inducible hsp70 promoter from Drosophila melanogaster, we showed that the nuclear v-sis protein accumulates in the nucleus within 30 min of induction. The identification of a nuclear transport signal in the v-sis gene product raises interesting questions regarding the possibility of some function for PDGF or PDGF-related molecules in the nucleus.
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PMID:Identification of a signal for nuclear targeting in platelet-derived-growth-factor-related molecules. 331 80

Sixty-six percent of rats immunized with laminin isolated from a mouse Engelbreth-Holm-Swarm (EHS) sarcoma developed moderate lesions in the testis characterized by multiple foci of seminiferous tubules with different degrees of sloughing of the germinal epithelium or atrophy intermingled with normal histological areas. Interstitial mononuclear cell infiltrates were seen in the epididymis. By electron microscopy, pathological changes in the basement membranes of the seminiferous tubules, such as splitting and focal thickenings of knob-like projections toward the epithelium, were observed. Moreover, Sertoli cell cytoplasm showed dilated smooth endoplasmic reticulum and large vacuoles. By electron microscopy with the immunoperoxidase technique, staining for in vivo-bound rat IgG was detected along the walls of the seminiferous tubules as a bright linear immunofluorescence and as a dense reaction product on the basal lamina. High titers of circulating antilaminin antibodies were detected by ELISA in all the rats immunized with laminin. As revealed by the skin test, a delayed type hypersensitivity reaction to laminin was observed in these rats.
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PMID:Testis lesions and cellular and humoral immune responses induced in rats by immunization with laminin. 332 74

A skeletal myxoid chondrosarcoma of the femur was examined by light and electron microscopy. Light microscopic features were characteristic for myxoid chondrosarcoma or "chordoid sarcoma." Electron microscopy disclosed crystalline arrays of microtubules within dilated rough endoplasmic reticulum, a feature previously described in extraskeletal myxoid chondrosarcomas. Tumors with the histologic characteristics of extraskeletal myxoid chondrosarcoma ("chordoid sarcoma") occurring in bone have been rarely reported. We describe herein such a tumor and document the existence of distinct microtubules within the endoplasmic reticulum.
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PMID:Skeletal myxoid chondrosarcoma with microtubular aggregates within rough endoplasmic reticulum. 333 20

The role of extracellular matrix as a determinant of intestinal cell maturation was explored by growing a normal, but immature, rat small intestinal cell line (IEC-6) on basement membrane extract from Engelbreth-Holm-Swarm (EHS) sarcoma cells (ECM). Grown on plastic or glass, these cells are relatively immature and proliferate rapidly. In contrast, cells on ECM attached more rapidly, stopped proliferating, and rapidly organized into multicellular complex structures. Ultrastructurally, cells grown on ECM displayed significantly more mitochondria, rough endoplasmic reticulum, apical microvilli, and complex golgi apparatus, consistent with greater maturity and synthetic activity. By indirect immunofluorescence, sucrase, alkaline phosphatase, and cellular apolipoprotein B were present in cells grown on ECM only. In contrast to cells grown on glass, these cells also demonstrated Na-dependent glucose absorption, a function unique to mature villus cells (7). We conclude that the basement membrane may be a key determinant of intestinal epithelial cell maturation. The development of a mature villuslike intestinal cell in vitro may have wide application for future studies of induction and regulation of intestinal maturation and function.
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PMID:Differentiation of rat small intestinal epithelial cells by extracellular matrix. 334 2

A recurrent mammary sarcoma from an 11-year-old, female domestic cat was studied by light and electron microscopy and immunohistochemistry. The tumor consisted of interlacing bands of spindle cells with elongated blunt-ended nuclei and variable amounts of stroma. Multinucleated tumor giant cells and mitoses were common. Ultrastructurally, tumor cells had abundant rough endoplasmic reticulum with dilated cisternae, a prominent Golgi complex, frequent mitochondria, bundles of intracytoplasmic filaments with focal densities, and discontinuous basal lamina-like material and cell junctions. These findings suggest that myofibroblast-like cells were the predominant type of tumor cell. Failure to demonstrate immunoreactivity for cytokeratins attested to the non-epithelial origin of these neoplastic cells. Uniform immunoreactivity with anti-vimentin antibodies and specific labelling of some tumor cells with antiserum to actin are compatible with an origin of this tumor from modified fibroblasts (i.e., myofibroblast-like cells). Tumors composed largely of myofibroblasts may be unique and warrant separate classification from other types of fibroblastic tumors in animals.
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PMID:Feline mammary sarcoma composed of cells resembling myofibroblasts. 396 79

The present study is based on electron microscopical examinations of 15 conventional chondrosarcomas, 1 clear cell chondrosarcoma, 3 mesenchymal chondrosarcomas, 2 so-called chordoid sarcomas (extraskeletal myxoid chondrosarcoma), 4 sacrococcygeal chordomas, 2 ecchordoses and 1 neoplasm of tibia with features of a true peripheral chordoma (parachordoma). The neoplastic cells from various types of chondrosarcoma shared a number of features with nonneoplastic chondrocytes as e.g. a well-developed rough endoplasmic reticulum and microvillous cytoplasmic processes. In clear-cell chondrosarcoma, glycogen accumulation in the tumour cells was a prominent feature. The cells of mesenchymal chondrosarcoma usually showed the characteristics of immature mesenchymal cells. In contrast, chordomas commonly contained physaliferous cells with two types of vacuoles in their cytoplasm. The first type can be most adequately characterized as intracytoplasmic pseudoinclusions of intercellular substance, whereas the other type, glycogen-containing, single membrane-bound vacuoles most probably correspond to autophagosomes (cytolysosomes). Only vacuoles of the first type were recorded in the so-called chordoid sarcoma. They were also seen in chondrosarcomas. In contrast, both types of vacuoles were identified in the above-mentioned tibial tumour which, in addition, showed even other cytological characteristics of chordoma. The findings presented here have demonstrated distinct structural relationships between chordoid sarcoma and chondrogenic tumours. On the other hand, our observation of the uncommon tibial neoplasm indicates the possibility that tumours identical with chordoma may occur at sites other than the axial skeleton.
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PMID:A comparative ultrastructural study of chondrosarcoma, chordoid sarcoma, chordoma and chordoma periphericum. 400 Oct 32

Extra-hepatic Walker sarcoma 256 produced a marked decrease (approximately 60%) in the levels of cytochrome P-450 and NADP-cytochrome P-450 reductase in rat liver endoplasmic reticulum, and a lesser decrease (approximately 20%) of cytochrome b5 and NADH-cytochrome b5 reductase. Polychlorinated biphenyls induced the synthesis of these cytochromes and reductases to approximately the same extent both in normal and tumor-bearing rats. The double-label technique was used to demonstrate that the synthesis of cytochromes P-450 and b5 was reduced in the liver of tumor-bearing rats. The turnover of P-450 was not affected by the tumor, whereas cytochrome b5 turnover was decreased. It is proposed that Walker sarcoma 256 mainly affects the transcription of cytochromes P-450 and b5 through a toxohormone, and that a regulatory mechanism coordinates the level of each cytochrome and its respective reductase.
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PMID:Effect of extra-hepatic Walker sarcoma 256 on the synthesis and degradation of liver cytochromes P-450 and b5. 642 47

Three infants presented with multiple nodular tumors of the omentum and mesentery characterized histologically by plump mesenchymal cells in a myxoid, well-vascularized stroma. Electron microscopy of one tumor revealed reticulated inclusions in dilated cisterna of endoplasmic reticulum. Diagnoses by the original pathologist, or by consultants from referral centers in the United States included liposarcoma, primitive sarcoma, possible leiomyosarcoma, and fibromatosis, but the subsequent evolution of the patients questions the validity of such diagnoses. Two patients received what was deemed ineffective therapy, yet survived with no evidence of disease for over a decade of close follow-up. Another patient received no therapy other than the initial surgery, and has been well for more than a year. Infantile lesions may show deceptive features of immaturity and high cellularity that are apt to be confused with a true malignancy. Omentalmesenteric "myxoid" lesions are probably hamartomatous in origin.
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PMID:Omental-mesenteric myxoid hamartomas. Infantile lesions simulating malignant tumors. 662 50

Clinicopathological ultrastructural, and immunohistochemical findings of a new case of IgG1 heavy chain disease are reported in detail. The abnormal protein lacks the VH and CH1 region with sequence starting at 225 residue. The main pathologic feature was plasmacytic tumor of the lymph nodes with B-cell immunoblastic sarcoma patterns. Neoplastic diffusion to other organs was also present. Plasmacytic neoplastic cells have also been found in the bone marrow. The ultrastructure of the noeplastic cells was characterized by more or less abundant plasmacytic-like endoplasmic reticulum with very frequent peculiar whorled configurations. Immunohistochemical methods revealed the abnormal protein production by neoplastic cells in different stages of differentiation. From this case and from the data of the literature it is concluded that the gamma HCD is due to a neoplastic proliferation of lymphoplasmacytic cells whereas the reticulum cells are never involved.
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PMID:G1 heavy chain disease: clinicopathological, ultrastructural and immunochemical study of a new case. 676 44

A mass in the axilla of a 47-year-old woman was biopsied and resected. The mass was composed of a loosely distributed population of spindle cells that were immunoreactive for smooth-muscle actin. Ultrastructurally, the cells possessed abundant endoplasmic reticulum, and some contained peripheral smooth muscle myofilaments, establishing that they were myofibroblasts. Mitotic activity was sparse, there was no cytologic atypia, and by flow cytometry the tumor was diploid with a low S phase. A diagnosis of myofibroblastoma was favored, although the possibility of a low-grade sarcoma could not be excluded. There has not been any indication of recurrence over a 4-month period of follow-up.
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PMID:Myofibroblastoma of the axilla. 757 Oct 83


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