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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study demonstrates the practical advantage of using more than one technique in evaluating breast tumors. Thionin stained, frozen sections and H & E stained, paraffin-embedded, permanent sections yielded a high degree of accuracy in differentiating benign from malignant lesions. Papanicolaou stain is essential for evaluating cytologic material. Special stains, enzyme histochemistry, and examination by SEM and transmission microscopy are essential in identifying the various cellular components of mammary tumors. On the basis of these techniques, fibroadenomas were defined as tumors of stromal cells of the lobule and sclerosing adenosis as a benign proliferation of myoepithelial cells; and it was suggested that mammary cancers may arise from myoepithelial ductal epithelial, or ductular epithelial cells. The behavior of the tumor is related to its cell of origin.
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PMID:Evaluation of the different techniques utilized in diagnosing breast lesions. 5 30

Six cloned astrocytoma cell lines derived from four ethylnitrosourea-induced F-344 rat gliomas were viewed by scanning electron microscopy in vitro, and two were examined in vivo after transplantation to the intracerebral site. All clones consisted of stellate cells that were reasonably homogeneous within individual glioma lines. Cell membrane features common to all tumor lines included microvilli, blebs, ruffles, and miniridges, mainly confined to perikarya, and filopodia emanating chiefly from cell processes. One cell line demonstrated a profuse, and another cell line a moderate, degree of microvillous development and cell surface roughening, which in one tumor correlated with rapid in vitro cell doubling time. Both cell lines maintained these topographical appearances when transplanted into brain. These results extend the SEM observations of astrocytomas, particularly in cloned ethylnitrosourea-induced tumors in rats. The confirm that distinct variations in cell membrane topography do occur among tumors of this type, probably irrespective of their origin in humans or rats, and irrespective of their mode of genesis as spontaneous, chemically-induced, or virally-induced tumors.
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PMID:Scanning electron microscopy of cloned astrocytic lines derived from ethylnitrosourea-induced rat gliomas. 9 59

SEM studies on infiltration of the ascitic form of the hamster reticulum cell sarcoma HaTu 25 into the ventral body wall and through the diaphragm were performed during 6 consecutive days after intraperitoneal transplantation. The findings allow an interpretation of the course of events based on 3 main stages: 1) Contraction of mesothelial cells with partial exposure of the submesothelial stratum. 2) Preferential attachment of tumor cells to these denuded areas. 3) Advance of tumor cells within defects gradually extening from the submesothelial stratum of the musculature. These stages were more pronounced and took a more rapid course at the peritoneal side of the diaphragm than at the body wall. At the pleural side of the diaphragm the appearance of single tumor cells within widened intercellular spaces of the mesothelium was recorded prior to the onset of penetration at the peritoneal surface. The rapid migration of tumor cells through the diaphragm as well as the particularly intensive tumor infiltration into this organ is thought to be connected with the mechanism of intravasation of tumor cells into the lymphatic plexus of the diaphragm. During the whole sequence of events, HaTu 25 cells were found to have maintained their spherical configuration and characteristic surface architecture. Apparently, growth pressure is of minor or no importance in this spacial mode of tumor penetration, rather the action of proteolytic enzymes elaborated by the tumor cells has to be taken into consideration.
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PMID:Penetration of an ascitic reticulum cell sarcoma of the golden hampster into the body wall and through the diaphragm. A scanning electron microscopic (SEM) study. 12 81

The concentration of hepatic nuclear T3 receptors was measured in isolated nuclei from athyreotic mice bearing thyrotrophic tumors and intact rats with Walker 256 carcinoma. Receptor concentration was reduced in all tumor-bearing animals. The mean receptor capacity of the Walker tumor-bearing rats [0.31 +/- 0.05 (SEM) ng/mg DNA] was significantly decreased from simultaneously assayed controls (0.47 +/- 0.04 ng/mg DNA; P less than 0.01). No change in the apparent equilibrium association constant was observed. In individual rats, the magnitude of the decrease in nuclear T3 receptor concentration was highly correlated with the decrease in tumor-free body weight. Additional studies showed that the decrease in nuclear receptors was not due to delayed equilibration of added T3 with nuclear sites in vitro or to an increase in endogenous hepatic T3 concentration. The plasma concentration of total and free T4 and T3 was decreased in tumor-bearing rats. Plasma TSH concentration, however, remained unchanged. Thus, these transplantable neoplasms seem to be associated with decreased hepatic nuclear receptors and low concentrations of plasma thyroid hormones. The unchanged plasma TSH suggests that the animals remained euthyroid.
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PMID:Decreased hepatic nuclear L-triiodothyronine receptors in rats and mice bearing transplantable neoplasms. 21 7

In 47 patients (46 children and 1 adult) with unilateral and bilateral retinoblastoma, the titer of the carcinoembryonic antigen (CEA) was determined. The CEA titer of children with active retinoblastomas was 1.44 +/- 0.26 ng/ml (x +/- SEM). Those patients whose retinoblastoma was inactivated by therapy did not show a significantly lower CEA titer. In the group of children with one eye removed because of a unilateral retinoblastoma, the CEA titer was significantly (P less than 0.1) lower. The globes of 25 children were examined histologically. In those cases with invasion of the optic nerve or choroid, the CEA titer was significantly higher (P less than 0.1) as compared with those where the tumor was limited to the retina alone.
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PMID:[Carcinoembryonic antigen in retinoblastomas (author's transl)]. 30 12

Morphologic responses of neoplastic human prostate to long-term explant culture were monitored at serial intervals by LM, TEM and SEM, and compared to normal prostate. Explants were cultured at 37 degrees C in CMRL-1066 supplemented with fetal calf serum and antibiotics. At 0-time culture, normal prostate of young adult males obtained at immediate autopsy, consisted of glandular spaces and ducts lined by columnar to cuboidal secretory epithelial cells and basal cells embedded in fibromuscular stroma. Neoplastic tissue was obtained surgically by transurethral resection (TUR), and consisted of stroma widely infiltrated by well-to moderately-differentiated tumor cells arranged in variable sized, gland-like structures. Secretory activity was evident; basal cells were absent in these glands. During early periods of culture up to several weeks, secretory cells of normal prostate became necrotic. Basal cells remained viable, repopulated acinar structures and epithelialized explant surfaces. At these sites, basal cells, or their derivatives, formed a multicellular epithelium. Exaggerated intercellular spaces separated cells, and synthesis of mucus-like material was seen. Epithelial characteristics included microvilli, junctional complexes, and basal lamina. In marked contrast, tumor cells covered explant surfaces forming an irregular, disorganized layer of squamous-like cells with elongated nuclei and prominent nucleoli. Microvilli, junctional complexes, and basal lamina were poorly developed or absent. Intercellular attachments appeared tenous. Some tumor cells accumulated lipid; synthesis of mucus-like material was not seen. At later intervals of culture up to 10 weeks, synthesis of mucus-like material by basal cells, or their derivatives, declined. Surface cells of neoplastic prostate gradually became more anaplastic in appearance; cells contacted neighboring cells with pseudopodia and filopodia.
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PMID:Studies on carcinogenesis of human prostate. IV. Comparison of normal and neoplastic prostate during long-term explant culture. 52 30

The fine structure of rat gliomas induced transplacentally with a single i.p. dose of 50 mg/kg of Ethylnitrosourea has been studied by using transmission and scanning electron microscope. The subependymal matrix layers of the fetus which was affected by ENU have showed irregular and rough arrangements with expanded extracellular spaces as compared with that of control rats. The cells of subependymal layer seemed to form the microtumor. A so-called "microtumor", which was found in a 8 week old, has been composed of small round cells. The fine structures of these cells have showed the characteristics in primitive oligodendroglioma. The characteristics of the fine structure of astrocytoma cells was identified by both TEM and SEM. The fine structure of subependymal glioma cells was often pleomorphic. These gliomas contained a mixture of primitive oligodendrocytes and ependymal cells together with anaplastic glial cells. With increasing size, the glioma has become more pleomorphic with a mixture of neoplastic oligodendrocytes, astrocytes and ependymal cells, and ependymoma like cells have showed neither cilia nor junctional complex. Abnormal vascular structure in the tumor has been reconfirmed by injection replica scanning electron microscope method. The fine structure of the separated single tumor cell surface was also studied by scanning electron microscope. The differences of the cells surface between that of astrocytoma cell and oligodendroglioma cells were clearly noticed.
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PMID:[Experimental brain tumors produced transplacentally by ethylnitrosourea (IV): ultrastructure studied by using transmission and scanning electron microscope (author's transl)]. 70 10

To evaluate the biological tolerance of the human liver to prolonged warm ischemia, two groups of extensive hepatic resection for tumor were compared. Group 1 (11 patients) performed with short hepatic inflow occlusion (7 [mean] +/- 2 [SEM] minutes), and group 2 (nine patients) operated with use of complete hepatic vascular exclusion and prolonged warm liver ischemia (38 [mean] +/- 5 [SEM] minutes). Comparison of biological values, such as transaminase, bilirubin, total protein, albumin, and fibrinogen levels, the platelet count, prothrombin complex, and proaccelerin level, did not show statistically significant differences between the two groups. Therefore, the hepatic warm ischemia period may be, if needed, safely extended beyond the classical 15 minutes. It lasted 65 minutes in one case without adverse effect. These clinical observations parallel recent experimental work and should destroy the myth of the high sensitivity of the liver to warm ischemia.
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PMID:Tolerance of the human liver to prolonged normothermic ischemia. A biological study of 20 patients submitted to extensive hepatectomy. 73 77

In view of the limitations associated with the present tumor markers for prostate cancer, we have examined the potential expression of two further markers, Cathepsin-D and pS2, in human prostate and attempted to link their concentrations with the histopathology of the tissue, the PSA levels and the androgenic status of the gland. Cathepsin-D and pS2 were measured in cytosol fractions obtained from 22 patients with benign prostatic hyperplasia (BPH) and 20 patients with prostate cancer (CaP) employing immunoassays specific for these markers. The concentrations of Cathepsin-D (BPH: mean +/- SEM = 18.50 +/- 1.88 nmol/g protein; CaP = 19.75 +/- 2.49 nmol/g protein) and pS2 (BPH = 1,024.7 +/- 348.06 ng/g protein; CaP = 1,513.88 +/- 268.60 ng/g protein) were not different in the two tissue types, whereas PSA in BPH tissue (1,952.27 +/- 249.93 micrograms/g protein) was significantly higher than the measurements in CaP (583.75 +/- 104.33 micrograms/g protein). However, none of the tumor marker concentrations correlated with the degree of differentiation of the tumors, and we were unable to establish any correlation with the levels of testosterone and dihydrotestosterone in the tissue. In conclusion, although Cathepsin-D and pS2 are expressed in prostate tissue, it is doubtful whether they will have an active role in the management of prostate cancer.
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PMID:The distribution of PSA, cathepsin-D, and pS2 in BPH and cancer of the prostate. 127 46

Monoclonal antibodies (MAbs) often distribute nonuniformly in tumors. In part, that observation reflects intrinsic heterogeneity within the tumor; in part, it reflects poor penetration through tumor substance. Several years ago, we proposed the "binding site barrier" hypothesis (J.N. Weinstein, R.R. Eger, D.G. Covell, C.D.V. Black, J. Mulshine, J.A. Carrasquillo, S.M. Larson, and A.M. Keenan, Ann. NY Acad. Sci., 507: 199-210, 1987; K. Fujimori, D.C. Covell, J.E. Fletcher, and J.N. Weinstein, Cancer Res., 49: 5656-5663, 1989), the idea that antibodies (and other ligands) could be prevented from penetrating tumors by the very fact of their successful binding to target antigen. Calculations suggested that this might be a significant factor in the therapy of even microscopic nodules. The higher the affinity and the higher the antigen density, the greater the barrier. Here, we provide direct experimental evidence of such a barrier to the percolation of D3 MAb through intradermally implanted line 10 carcinoma of guinea pigs. After affinity purification using glutaraldehyde-fixed line 10 cells, the D3 had an average immunoreactivity of 88%, a binding constant of 1.6 +/- 0.3 (SEM) x 10(10) M-1, and saturation binding of 355,000 +/- 15,000 molecules/cell. Using a combination of double-label autoradiography and double-chromagen immunohistochemistry, we determined simultaneously the distribution of (a) i.v. injected D3 MAb; (b) coinjected isotype-matched control IgG (BL3); (c) D3 antigen; (d) blood vessels. The previously developed mathematical models aided in the design of these experiments. Double immunochemical staining of the tumors showed antigen-rich patches 100-800 microns across, surrounded by blood vessels. At a low MAb dose (30 micrograms), binding to antigen severely hindered penetration into antigenic patches as small as 200 microns, even at 72 h. Explanation of this finding by a physical barrier was ruled out by the observation that BL3 distributed uniformly in the same patches. At a higher dose (1000 micrograms), the binding site barrier could be partially overcome. The same general principles of micropharmacology may apply to biological ligands other than antibodies, including those secreted by genetically modified cells.
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PMID:Micropharmacology of monoclonal antibodies in solid tumors: direct experimental evidence for a binding site barrier. 132 1


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