Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A rare, distinctive neoplasm occurring in the soft tissue of the extremities and resembling chordoma has been recently described and variously termed "chordoid sarcoma," "chordoid tumor," and "parachordoma." An example of this tumor occurring in the flank is presented. The tumor lacks the ultrastructural features associated with chordomas. Moreover, the tumor appears to be elaborating an abundant matrix of sulfated acid mucopolysaccharide interspersed with collagen fibers in varying stages of maturation. These features suggest that the tumor is exhibiting chondroid, rather than chordoid, differentiation. Previous reports of extraskeletal myxoid chondrosarcoma bear a striking light microscopic and electron microscopic similarity to the "chordoid sarcoma," suggesting that the latter is a variant of extraskeletal myxoid chondrosarcoma.
 ...
PMID:Ultrastructure of the so-called "chordoid sarcoma". Evidence supporting cartilagenous differentiation. 12 78

Synthetic aromatic analogs of retinoic acid were administered i.p. and p.o. to Fischer F344 rats bearing a transplantable chondrosarcoma. 35CO4 incorporation into glycosaminoglycans were compared for neoplastic and normal cartilage explants after removal from animals given various analogs. There was a direct relationship between [35S]glycosaminoglycan synthesis by chondrosarcoma chondrocytes and inhibition of tumor growth. The degree of inhibition of [35S]glycosaminoglycan synthesis in the neoplastic cartilage was dependent on the dose of the retinoid administered. At 20-mg/kg/day doses of retinoid for 4 weeks, 35SO4 incorporated into glycosaminoglycan by treated tumor explants was reduced as much as 95%. There was no reduction of [35S] glycosaminoglycan produced in normal costal cartilage of the same animals. Retinoid treatment of 20-mg/kg/day doses for 4 weeks resulted in a 75% reduction in glycosaminoglycan per mg of chondrosarcoma; there was no reduction in costal cartilage glycosaminoglycan. Retinoid (10- to 20-mg/kg/day doses) elevated collagen levels per mg of chondrosarcoma but had no effect on costal cartilage collagen. Combined in vitro and in vivo studies showed that retinoid administration modified neoplastic chondrocyte function but had no measurable effect on normal chondrocyte function.
 ...
PMID:Effect of aromatic retinoids on rat chondrosarcoma glycosaminoglycan biosynthesis. 13 54

Several benign and malignant tumors of bone and cartilage were examined by means of type-specific collagen antibodies in connection with indirect immunofluorescence technique in order to determine wether there is a positive correlation between cell morphology and gene expression as refered to the synthesis of tissue- or cell-specific collagen. In general benign bone and cartilage tumors show the collagen type corresponding to the original maternal tissue. In malignant osteogenic tumors a strong positive correlation was found between morphologic differentiation of osteosarcoma cells and tissue specific collagen synthesarcomas. Unrelated to the grade of differentiation and the type of malignant tumor, collagen type III could be demonstrated in all tumors investigated, occurring rather from vascular stroma than from the tumor cell itself.
 ...
PMID:Immunhistochemical demonstration of different collagen types in the normal epiphyseal plate and in benign and malignant tumors of bone and cartilage. 14 52

Two cases of aggressive fibromatosis of the thyroid gland region were studied by histological, immunhistological and electron-microscopic methods. Contractile cells can be found in all tissue preparations using human serum containing antibodies to smooth muscle, especially in the periphery of the tumor. These cells have the characteristics of myofibroblasts by electron microscopy. The central areas of the tumor are composed of hyalin thickened bundles of collagen fibres with few cellular elements. The myofibroblast is thus considered to be the characteristic cell type of the tumor, and the pathogenesis and histogenesis of the lesion are discussed.
 ...
PMID:[Fibromatosis of the thyroid gland region. An electron-microscopic and enzyme-histochemical study (author's transl)]. 14 58

A capillary hemangioblastoma from the vermis of a 21-year-old man with von Hippel-Lindau's disease was successfully maintained in organ culture systems on Millipore filter platforms and gelatin sponge foam matrices up to 48 days. Three cell types--endothelial cells, pericytes, and stromal cells--identified by their fine structural features and their architectural relationships to vascular lumens and to the extracellular space were recognized in the original tumor. By light microscopy the explants showed, in the late stages, increased lipid droplets in the stromal cells and perivascular hyaline thickening. By electron microscopy, endothelial cells, pericytes, and stromal cells remained distinguishable as cell types. However, the stromal cells demonstrated, in addition to an increase of their normal complement of microfilaments and lipid droplets, features that were more characteristic of the two other cell types, i.e. micropinocytotic vesicles and the formation of zonula occludens junctions and hemidesmosomes. Basement membranes also became more apparent around the stromal cells. With increasing time in vitro, there was a striking increase in mature collagen fibers in the extracellular space. The roles of the different cell types in capillary hemangioblastoma and the histogenesis of the stromal cells are discussed in light of these observations. It is concluded that the capillary hemangioblastoma consists of multiple cell lines--endothelial cells, pericytes, stromal cells and, occasionally, hematopoietic cells--all of which are neoplastic and replicate in parallel with one another. Stromal cells may be regarded as an aberrant monopotential cell type which shares with the endothelial cell and pericyte a common mesenchymal, presumably angiogenic, ancestry, and may, on occasion, display morphological features, such as increased basement membrane formation and the formation of zonula occludens junctions, which recall its angiogenic lineage. However, interconvertibility between endothelial cells and stromal cells does not appear to occur in vivo or in vitro.
 ...
PMID:Cerebellar capillary hemangioblastoma: its histogenesis studied by organ culture and electron microscopy. 16 32

A sensitive assay system, optimally supplemented with tritiated protocollagen substrate and cofactors, is described which is suitable for determining the peptidyl proline hydroxylase (PPH) content of a wide spectrum of rat tissues. In most tissues, less than 50 percent of the total activity was soluble; the particulate portion of the activity (concentrated in the mitochondrial and microsomal fractions) was doubled by pretreatment with Triton X-100. Among normal adult tissues, lung had the highest total PPH activity (2.4 times that of liver) and small intestine had the lowest (25 percent that of liver). In brain and lactating mammary gland, the activity was similar to that in skin (60 percent of that in liver). Fetal tissues contained 3 to 8 times more PPH than the corresponding adult tissues, and a much lower portion of the total activity was soluble. In four tissues studied in detail (lung, liver, kidney, and brain), the total PPH declined rapidly during the last few days of gestation; brain attained its low adult value before term, whereas the other three tissues continued to decrease in the course of postnatal development. An injection of cortisol to fetal rats enhanced the decline of PPH in lung, liver, and skull. These experiments suggest that during normal differentiation the decline in collagen synthesis is initiated by fetal glucocorticoid secretion which is maximal on the 19th gestational day. PPH activity appears to be a sensitive indicator of neoplastic growth. In renal, mammary, muscle, and hepatic tumors, the PPH activities were 4 to 10 times higher than in the cognate adult tissue. Even in well-differentiated, slowgrowing tumors, the activity was considerably higher than in any normal, mature, or immature tissue, with the exception of the skull and lung of the 19-day-old fetus.
 ...
PMID:Peptidyl proline hydroxylase in adult, developing, and neoplastic rat tissues. 16 93

The ultrastructural findings in a case of odontogenic myxoma are described. The main cell type was characterized by several cytoplasmic processes, intracytoplasmic fibrils, numerous glycogen particles, and salient Golgi complexes. A few mitochondria and a scarce endoplasmic reticulum was noted. The matrix consisted of numerous granules with fibrillar projections, collagen bundles, and smaller fibers. The over-all ultrastructural features of this tumor were similar to those described in the human cardiac myxoma and in Wharton's jelly and could be clearly differentiated from the fine structural characteristics of other connective tissue tumors.
 ...
PMID:Ultrastructure of an odontogenic myxoma. 16 99

The various stages of divergent neuroepithelial differentiation were studied in the solid transplants of a transplantable mouse testicular teratoma (OTT-6050) maintained in both ascitic and solid forms. They included: a) areas of undifferentiated medullary epithelium corresponding to the rare human medulloepithelioma; b) areas of neuroblastic differentiation corresponding to neuroblastoma, with more mature neuronal differentiation corresponding to ganglioneuroma or, when mixed with glial elements, to ganglioglioma; and c) more mature neuroglial areas resembling astrocytoma, oligodendroglioma or ependymoma, as well as more primitive areas corresponding to ependymoblastoma. In tissue culture using collagen-coated coverslips, astrocytic differentiation was found in the outgrowth zone after 15 days, confirmed by immunofluorescence with antibodies to an astroglia-specific protein. In organ culture systems, glial components, including ependymal structures, were preserved in tumor explants, and astrocytic differentiation, as expressed by glial fiber formation, was increased after 4 to 6 weeks in vitro. No neuronal differentiation was demonstrable, however. The neuroepithelial component of this experimental teratoma may provide a model for the study of neoplastic neuroepithelial differentiation.
 ...
PMID:An experimental mouse testicular teratoma as a model for neuroepithelial neoplasia and differentiation. I. Light microscopic and tissue and organ culture observations. 16 76

Summary--Tumor invasion requires the breadkdown of the main structural protein, collagen. A series of fourteen epidermoid carcinomas of the larynx and oral cavity produced a collagen dissolving enzyme in vitro as demonstrated by the breakdown of 14C-labeled collagen. Oral cavity tumors showed greater activity than laryngeal carcinomas while both sites were more active than uninvolved mucosa from the same patients. Tumor associated collagenase activity, in common with previously described collagenases, can only be demonstrated in vitro and requires protein synthesis. Maximum tumor collagenase occurred at 24 hours in vitro and then declined as compared with the maximum collagenase at 72 hours in vitro produced by oral cavity mucosa. The 14 patients in our series were ranked in order of the collagenase activity of their tumors. At 18 months after the diagnosis, four of the six patients with the most active tumors were dead of cancer and one patient was alive with persistent cancer. High collagenase activity may be a factor in the clinical aggressiveness of epidermoid carcinomas of the head and neck.
 ...
PMID:Collagenase activity in epidermoid carcinoma of the oral cavity and larynx. 16 14

An organ culture method suitable for the maintenance of viable human breast cancer for at least 14 days has been described. This method was applied to a total of 94 breast cancer specimens. It allowed good survival of "soft" tumors of various histological types, with loose connective stroma even in hormone-free medium. In contrast, "scirrhous" cancers showed poor survival in hormone-free medium; viable cells were maintained only at the very periphery of the explants. Supplementation of the medium with insulin (10 mug/ml), ovine prolactin (5 mug/ml), and hydrocortisone (1 mug/ml) in various combinations seemed to induce enlargement of viable cancer cells and moderate loosening of the stroma in some cases. However, it did not improve the survival of central tumor cords in scirrhous explants. Further supplementation of the medium with 17 beta-estradiol (minimum effective dose, 0.1 to 10 ng/ml), although it did not affect soft tumors, markedly improved survival of the cancer cells of scirrhous tumors throughout the whole explants, with evidence of collagen digestion around the neoplastic cells. This was observed in 18 of 20 scirrhous cancers subjected to this treatment. Estradiol need not be present during the whole culture period; the results at 14 days were identical in explants treated with estradiol for the first 7 days only or for the entire period. Addition of purified collagenase during the first 24 or 48 hr of culture resulted in complete dissolution of the collage. After such treatment, culture under the usual conditions resulted in excellent survival of the explants without improvement from hormone supplementation; thus, while estradiol was necessary when collagen was present, it was not longer required after collagen digestion. It can be concluded that breast cancer cells in organ culture are only slightly, or not at all, hormone dependent for survival, provided that they are not restrained by a dense collagen barrier. The estrogen-induced changes allowing survival inside the scirrhous explants strongly suggest the presence of an estrogen-dependent collagenolytic enzyme system in the collagen-rich breast cancers. This system could represent an important component of the hormone dependency of human breast cancer growth.
 ...
PMID:Estradiol-dependent collagenolytic enzyme activity in long-term organ culture of human breast cancer. 16 44


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>