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

An ultrastructural dopa reaction, with glutaraldehyde--formaldehyde prefixation, was carried out on ten specimens of malignant melanoma showing a wide variation in melanosomal morphology. All tumours, but only a minority of tumour cells, contained reaction product. In all tumours the reaction product was distributed similarly in the Golgi apparatus and Golgi associated endoplasmic reticulum (GERL). However, differences were noted in its deposition in melanosomes. Whereas vacuolar and lamellar profiles sometimes contained reaction product, it was not seen in normal, granular and abortive melanosomes. Tumour cells without melanosomes were also seen to contain reaction product.
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PMID:Human malignant melanoma. Melanosomal polymorphism and the ultrastructural dopa reaction. 63 44

Two types of testicular tumor were evident in cyprinid fishes collected from Lake Ontario. Both types of tumors appeared to be of Sertoli cell origin. One contained predominantly Sertoli cells with little or no lipid content and germinal cells in only small numbers. The second contained large numbers of spermatogonia together with Sertoli cells that contained large amounts of lipid and smooth endoplasmic reticulum. Small, apparently inactive Leydig cells were present in both types of tumors and also in testes of fish not bearing gonadal tumors.
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PMID:Structure of normal testis and testicular tumors in cyprinids from Lake Ontario. 68 7

Four cases of spontaneous adenocarcinoma of the canine exocrine pancreas were studied by thin section and freeze-fracture electron microscopy. The neoplastic cells in all 4 cases were of acinar origin and showed many alterations of cytoarchitecture compared with normal acinar cells. In the neoplastic cells, zymogen granules varied in number and appearance and contained an abnormal secretory product characterized by 24-nm-thick microtubules. The nuclear volume and surface area and the nuclear cytoplasmic ratio were increased; although the nuclear pore density per nuclear surface area was significantly decreased, there was no change in the nuclear pore density per nuclear volume. There was a decrease in number and size of gap junctions; focal proliferation, fragmentation, and discontinuation of the tight junctions were also noted. The basal lamina (BL) of the neoplastic cells was discontinuous. The tumor microvasculature often appeared as sinusoids and had sparse discontinuous BL. Finally, the endothelium in both tumor and normal tissue contained "tubulo-reticular inclusions" (TRI) which simulated distemper virus and were located in the rough endoplasmic reticulum (RER) and the perinuclear cisternae.
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PMID:An ultrastructural study of acinic cell carcinomas of the canine pancreas. 69 3

The prominent finding on electron microscopy of an unusual spongy variant of medulloblastoma was the marked distention of a well-developed smooth endoplasmic reticulum of the tumor cells. To the authors' knowledge, this fine structural feature has not been described previously in this tumor.
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PMID:Fine structure of an unusual spongy variant of medulloblastoma. 70 49

The light and electron microscopic features of a so-called chordoid sarcoma arising in the area of the gastrocolic ligament are described and illustrated. Despite the tumor's histologic resemblance to chordoma, the ultrastructural markers are those of chondroid rather than chordoid neoplasms. These are well-developed, vesciular granular endoplasmic reticulum, intracytoplasmic glycogen, lipid bodies, and a collagen-poor extracellular matrix with electron-dense granules, presumably representing chondroitin sulfate. Similar submicroscopic alterations have been observed in extraskeletal myxoid chondrosarcomas. Because of the distinctive morphologic appearance of this peculiar lesion, the term "myxoid chondrosarcoma with chordoid features" is suggested to reconcile histologic and ultrastructural features and histogenesis.
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PMID:Extraskeletal myxoid chondrosarcoma with "chordoid" features (chordoid sarcoma). 70 36

Pituitary adenomas composed of oncocytes are rare. We report a young female with an atypical oncocytic tumor of the pituitary. The histology was unusual because the oncocytic cells--in addition to an abundance of abnormal mitochondria--contained a conspicuous smooth endoplasmic reticulum. The tumor grew invasively and the patient developed adrenal hypercorticism.
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PMID:Pituitary oncocytic tumor with Cushing's disease. 70 33

The specific activity of 17beta-hydroxysteroid dehydrogenase was measured in normal human myometrium, and in leiomyoma specimens obtained from the same tumor-bearing uterus. In all cases the normal tissue showed greater conversion of estradiol-17beta into estrone than the neoplastic tissues. In normal myometrium of fertile women, the specific enzyme activity depended on the phase of the menstrual cycle, the highest values of 17beta-hydroxysteroid dehydrogenase activity being found in the early secretory phase. To determine the intracellular distribution of the 17beta-hydroxysteroid dehydrogenase, purified microsomes, mitochondria, nuclei and cytosol fractions were prepared. The purity of each fraction was monitored by marker enzymes. It was found that the enzyme was mainly located in mitochondria and microsomes. Furthermore it was demonstrated that the microsomal enzyme was bound tightly to the membranes of the endoplasmic reticulum, while the mitochondrial 17beta-hydroxysteroid dehydrogenase was mainly associated with the outer membranes of the organelle. Kinetic parameters (Km-values, coenzyme requirements, temperature and pH-optima) of the cytoplasmic, nuclear, mitochondrial and microsomal enzyme of normal and neoplastic tissue were compared.
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PMID:In vitro conversion of estradiol-17beta into estrone in normal human myometrium and leiomyoma. 71 40

Six solitary (localized) pleural mesotheliomas were studied by light and electron microscopy. All the lesions were benign and were composed mainly of fibrous tissue of variable cellularity with or without cystic spaces lined by round cells. The lining cells of the cysts and the adjoining round plump cells were interpreted as true neoplastic cells of the fibroblast type. Results of light- and electron-microscopic study of human mesothelial cells and fetal mesothelial cells of rats were compared. The cytoplasmic organelles of the tumor cells were generally scanty, though rough endoplasmic reticulum, sparse mitochondria, intracellular bundles of fibrils, and numerous polysomes were seen. Some tumor cells had junctional apparatus and basement membrane and showed interdigitation of the plasma membrane. These cells lined the cystic spaces irregularly and also proliferated into the surrounding fibrous tissue, where they assumed a spindle shape and resembled fibroblasts. Ultrastructurally, the tumor cells were similar to mesothelial and stromal cells of fetal rat pleura. We speculated that the solitary (localized) mesotheliomas were probably derived from coelomic epithelium and that tumor cells remained undifferentiated or revealed minimal differentiation toward mesothelial cells.
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PMID:Solitary (localized) pleural mesothelioma. A light- and electron-microscopic study. 73 11

A null cell fraction was isolated from human peripheral blood by Ficoll density gradient centrifugation followed by removal of mononuclear phagocytes, passage through Ig-antiIg columns and sedimentation of E-rosette forming T cells. In contrast to the T cell fraction in the Null cell population exhibited cytotoxic activity against antibody-sensitized human melanoma target cells (ADCC reaction). This activity could be attributed to a low affinity Fc-receptor bearing cells present in the Null cell preparation. At the ultrastructural level in 2 h ADCC reaction most tumor cells were surrounded by up to 10 lymphoid cells which showed narrow junctions with parallel plasma membranes and local evaginations of lymphoid cells into recessus of the target melanoma cells. The mononuclear cell type found in close contact with the antibody-sensitized target cells had the following morphological criteria: 8 to 10 mu diameter, irregular nucleus, discrete rough endoplasmic reticulum, isolated ribosomes, cytoplasmic organelles concentrated under a ruffling membrane in the contact area with the tumor cell.
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PMID:Human peripheral Nullymphocytes: ultrastructural aspects of the "K" cell effect against a melanoma target cell. 73 73

A case of a primary intracranial embryonal carcinoma, the first with ultrastructural study, is reported. The tumor was associated with precocious puberty in a 6 1/2-year-old female. Characteristic embryoid bodies were present. At the ultrastructural level three cell types were noted: undifferentiated, differentiated, and intermediate types. The undifferentiated showed scanty cytoplasmic organelles and numerous free polysomes, while the differentiated cells contained well-developed mitochondria, Golgi apparatus, rough endoplasmic reticulum, and some contained secretory granules. The intermediate cells possessed dilated and irregularly-shaped mitochondria but still retained large numbers of free polysomes. The authors suggest that intracranial germ cell tumors be named in conformity with germ cell tumors in other sites, and that terms such as "ectopic pinealoma" and "atypical teratoma of the pineal" be used no longer.
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PMID:Case report and ultrastructural study of intracranial embryonal carcinoma. 74 54


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