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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aggregates of tubular arrays associated with cysternae of endoplasmic reticulum were observed in untreated primary American form Burkitt's lymphoma. The tumor occurred in a white female child who died with severe central nervous system (CNS) involvement. Although the significance of the tubular structures and the mechanism by which they are formed remains unknown, the predilection of these structures for lymphoid and reticuloendothelial cells and their frequent association with either viral or suspected viral conditions cannot be overlooked. However, it is possible that the tubular structures may reflect an increased production of antibody protein in response to a viral antigen.
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PMID:Cytoplasmic tubular arrays in cells of American Burkitt's type lymphoma. 17 97

The electron microscopic examination of 13 biopsy specimens of livers that contained metastatic carcinoma revealed degenerative alterations of the mitochondria, cystic dilatation of the endoplasmic reticulum, increased amounts of osmiophilic material, some in various stages of autophagocytosis, and lipid vacuoles within the hepatocytes. In ten of 13 cases, the hepatocytes demonstrated mitochondrial paracrystalline inclusions. The observation of the latter structures in edematous hepatocytes containing phospholipid-rich osmiophilic deposits tends to confirm the experimental hypothesis that paracrystalline inclusions are caused by the precipitation of unmasked phospholipids. The spectrum of ultrastructural findings suggests hypoxia and impaired lipid metabolism of the hepatic tissue as a result of congestion and bile stasis caused by the tumor nodules.
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PMID:Ultrastructural alterations in livers with metastasis. 17 65

The ultrastructural configuration of the cells in one case of pregnancy luteoma was studied by conventional electron microscopy. The fine structure of these cells conforms closely to that of steroid hormone producing cells in other human organs, such as the adrenal cortex, testicular interstitium, and corpus luteum, particularly in terms of the presence of abundant smooth endoplasmic reticulum, dispersed Golgi apparatus, and tubular cristae in the mitochondria. Similarities were noted between the pregnancy luteoma cells and, as described by other authors, the luteinized granulosa and theca cells of the human corpus luteum and the cells of spontaneous mouse luteoma. There was a more pronounced resemblance to the granulosa cells of the corpus lutemum than to the luteinized theca cells or the mouse luteoma cells but with considerable overlap among all of them. Distinctive features, not previously described, were noted in the pregnancy luteoma cells in the form of deep cytoplasmic invaginations of the cell membrane closed by tight junctions, and peculiar pleated sinuous membranous arrays within the cytoplasm. The significance of these structures is not known. In addition mesenchymal cells of ambiguous differentiation were noted in the stroma of the tumor, suggesting that the stimulus to luteinized cell proliferation may transcend the specific ovarian mesenchymal cells and may also be exerted on the supporting stroma. On the basis of previous reports concerning the biochemical and biosynthetic patterns of sex steroid hormone production by these tumors, it is concluded that although the latter recapitulate the endocrine functions of the normal ovarian stroma rather than those of the corpus luteum, the cytoarchitecture of these tumors covers a much broader spectrum of differentiation, which may come to resemble closely although not exclusively that of luteinized granulosa cells.
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PMID:Luteoma of pregnancy: ultrastructural features. 17 51

A multilaminar alteration of endoplasmic reticulum (ER) has been observed in tumor cells of eight patients with Hodgkin's disease and a patient with histiocytic lymphoma. These multilaminar structures are more numerous in dividing cells and thus appear to arise primarily during mitosis. The stacked membranes in the multilaminar structures possibly result from abnormal sticking of organelle membranes, as evidenced in this study of adherence of ER to other elements of ER, nuclear envelope, mitochondria, or lipid droplets. Multilaminar ER was identified in all mitotic tumor cells, a rare mitotic plasma cell, and numerous interphase Hodgkin cells. The paucity of multilaminar ER in normal mitotic cells and its virtual absence for normal interphase cells suggest that this structure represents a pathological alteration in tumor cells from patients with Hodgkin's disease and histiocytic lymphoma. The multilaminar defect of ER is associated with other atypical features of ER in Hodgkin tumor cells, including the excessive length and curving of ER profiles, the collapse of the ER cisternae, and the overall sparsity of this organelle. Other abnormalities observed in mitotic Hodgkin tumor cells include the presence of disorganized microtubules, large cytoplasmic vacuoles, and abnormally clumped chromosomal material and the persistence throughout mitosis of bodies suggestive of nucleoli and of the nuclear bodies of interphase cells.
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PMID:Multilaminar endoplasmic reticulum and abnormal mitosis in Hodgkin tumor cells. 17 30

Electron microscopic examination on three lines of transplantable reticulum cell sarcomas, induced spontaneously in the mesenteric lymph nodes of inbred strain ACI rats, proved the presence of intracisternal A particles in all the three tumor lines. The doughnut-shaped particles measured 50 to 70 nm and were seen to bud from the membranes of rough-surfaced endoplasmic reticulum. Frequency of appearance of these particles varied with the tumor line.
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PMID:Intracisternal A particles in transplantable reticulum cell sarcoma of rats. 17 61

Smooth and rough endoplasmic reticulum from rat liver and hepatomas exhibited endogenous protein kinase activity independent of adenosine 3':5'-monophosphate. The phosphorylation of smooth membranes by this process was consistently higher than that of rough membranes. When histone was added along with the smooth endoplasmic reticulum, cyclic AMP stimulated protein phosphorylation. Analysis of membrane-phosphorylated proteins by gel electrophoresis showed 5 major phosphorylated bands with estimated molecular weights of 155 000, 62 000, 50 000, 46 000 and 43 000, whereas major bands having estimated molecular weights of 62 000, 50 000 and 43 000 were found in membranes of the smooth endoplasmic reticulum of the Morris hepatoma 5123 C. Since previous studies in this and other laboratories have demonstrated the similarity of the protein components of membranes of the endoplasmic reticulum of normal liver and hepatoma, our findings indicate an inability of the protein kinase of hepatoma intracellular membranes to phosphorylate protein species that are found in membranes of both liver and the neoplasm.
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PMID:Protein phosphorylation of the smooth and rough endoplasmic reticulum in normal and neoplastic liver of the rat. 18 Dec 47

We induced pancreatic adenocarcinomas in Long-Evans rats by placing crystals, 2-3 mg, of 7,12-dimethylbenz[a]anthracene (DMBA) in a 2- to 3-mm incision in the "head" of the pancreas approximately 1 cm from the duodenum. The incisions were closed with one or two silk sutures. The animals were killed 4-10 months after DMBA implantation, and nodules were removed and routinely prepared for light and/or electron microscopic study. Histologic organization varied from normal, through areas of tubule-like structures, to sheets of pleomorphic tumor cells. Electron microscopic study of tumor cells revealed large electron-lucent nuclei that frequently had irregular outlines and prominent nucleoli. The predominant feature of the cytoplasm was abundant rough endoplasmic reticulum. Zymogen granules were rare. Adjacent cells sometimes were jointed by an apical junctional complex to form a lumen into which projected irregular microvilli. A basal lamina sometimes occurred at the bases of the tumor cells. The fine structural similarity of these tumor cells to acinar cells was noted.
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PMID:Fine structure of pancreatic adenocarcinoma induced in rats by 7,12-dimethylbenz(a)anthracene. 18 82

Two cases of infantile carcinoma of the pancreas were diagnosed as pancreatoblastoma based on the morphogenesis of the tumors. These encapsulated tumors adhered to the head of the pancreas and to the descending portion of the duodenum. Histologic examination revealed an organoid structure made up of cords or nodules of squamoid cells with elongated nuclei arranged in a parallel fasciculating pattern (squamoid corpuscles), surrounding tubular structures of columnar epithelial cells and intermediate light cell masses with little differentiation. Electron microscopy revealed zymogen-like granules and well developed granular endoplasmic reticulum in the cytoplasm. There were no detectable islet cells in tumor tissue. Both of these tumors could be derived from the ventral pancreas and be isolated by the lack of communication with the duct of Wirsung. As the duct of Santorini was patent, extirpation of these organoid tumors would not influence secretion of pancreatic juice. Considering the favorable prognosis after extirpation of these tumors, they should be differentiated from the usual adenocarcinoma of the pancreas occurring in adults.
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PMID:Morphogenesis of pancreatoblastoma, infantile carcinoma of the pancreas: report of two cases. 18 39

Daily sc injections of 8 mg N6, O2'-dibutyryl 3',5'-cyclic AMP (DBcAMP) beginning 1 day after tumor implantation significantly increased the growth rate of R32230AC rat mammary adenocarcinomas, which nearly doubled in in situ volume by day 40 compared to similarly implanted tumors in saline-injected controls. Weights of excised tumors, intact, drained, and dried all increased approximately 80%, which suggested that the increase in tumor size was not due to accumulation of secreted fluid or tissue water. Injections of 17beta-estradiol valerate (0.1 mg/wk) from day 1 or of DBcAMP from day 22 resulted in insignificant changes in growth--28% and 35% increases in tumor volume and a 5% decrease and an 18% increase, respectively, in drained wet weight. Electron microscopic examination revealed that estrogen and DBcAMP caused differentiation of the tumor cells into two different states: Estrogen-treated tumors resembled lactating mammary glands; they contained large lipid droplets, organized rough endoplasmic reticulum, and vesicles containing electron dense granules resembling protein. DBcAMP-treated tumor cells were marked by a proliferation of the Golgi complex and numerous vesicles containing fine granular material.
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PMID:Enhancement of R3230AC rat mammary tumor growth and cellular differentiation by dibutyryl cyclic adenosine monophosphate. 19 Apr 20

An adrenocortical adenoma associated with adrenogenital syndrome in a two-year-old boy was investigated light and electron microscopically. Urinary 17-ketosteroid excretion was considerably elevated and unresponsive to dexamethasone administration. The level returned to normal after surgical removal of the tumour. Adenomatous cells display striking cellular and nuclear pleomorphism. Megalocytes with huge nuclei and nucleoli frequently occur. Deep cytoplasmic indentations cause nuclear pseudoinclusions and bizarre shape of the nuclei. True nuclear inclusions are also seen, as well as nuclear fragmentation. Cytoplasmic organelles show striking morphological alterations. Mitochondria with lamellar and tubular cristae are transformed into round or ovoid organelles of vesicular type. Their internal compartment is reduced, matrix material increases relatively, and mitochondrial inclusion bodies develop. Mitochondrial inclusions are identified as corresponding to fuchsinophil (siderophil or argyrophil) granules seen in the light microscope. Their staining properties indicate their glycoprotein nature. Vesicular profiles of smooth endoplasmic reticulum predominate and stacks of rough endoplasmic reticulum are transformed into tubules and vesicles. In Golgi regions, only vesicular elements are enriched. Lipid droplets are scarce. It was not possible to demonstrate histochemically catalase activity in microbodies. Dense bodies only occur in small, undifferentiated tumour cells. Multivesicular bodies, autophagosomes and residual bodies are rare. Lipofuscin is absent. Tumour cells are thought to derive from a population of undifferentiated cells ("germinative tumour cells"). Their morphological features and organelle equipment during a hypothetical course of differentiation and following dedifferentiation is described and discussed with respect to exceeding androgen synthesis.
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PMID:Fine structure of a virilizing adrenocortical adenoma. 19 90


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