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  • 1
    ISSN: 1432-0533
    Keywords: β-Endorphin ; Corticotropin-releasing factor ; Cushing's disease ; Nelson's syndrome ; Pituitary adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tissues from 12 human corticotropin-secreting adenomas, obtained during surgery for Cushing's disease (CD, ten cases) or Nelson's Syndrome (NS, two cases), were exclusively mechanically dispersed. Single cells and cell aggregates were plated on extracellular matrix derived from bovine corneal endothelia. Functional responses to physiological stimuli were analyzed by measuring human β-endorphin (βh-EP) immunoreactivity (IR) by radioimmunoassay in the culture medium. All adenomas responded with stimulated secretory activity to arginine vasopressin (AVP), corticotropin-releasing factor (CRF), or both. Cortisol higher than 10−8 M suppressed basal secretion and CRF- or AVP-stimulated βh-EP-IR secretion. There was no consistent difference in response of the cells when cultured in medium containing 10% fetal calf serum (FCS) or in serum-free conditions. A change of cells from serum to serum-free conditions usually resulted in 10%–50% reduction in the basal secretion level that remained stable for at least 2 weeks and, in one case (NS), 10 weeks. In cells maintained in medium supplemented with 5% serum obtained from the respective patients 40 min after adenoma removal, basal secretion was suppressed to 60% of the baseline level in a 10% FCS control. Long-term incubation with CRF (10−9 M) showed sustained stimulation of hormone secretion. No remarkable cell proliferation was observed under basal conditions or during long-term, low-dose incubation with cholera toxin (10−12 M) in two cases (CD), or CRF (10−9 M) in two cases (NS, CD). Parallel β-EP-IR and adrenocorticotropin secretion was verified in selected cases.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 47 (1979), S. 21-25 
    ISSN: 1432-0533
    Keywords: Cell kinetics ; Stathmokinetic analysis ; Glioma ; Mitostatic agent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twelve patients with gliomas received3H-thymidine intraarterially in combination with an i.v. mitostatic agent (Velban: 0.1 mg/kg or 3 mg/M2 of Vincristine) prior to tumor biopsy. The labeling index (LI) of each tumor was compared with the mitotic index divided by the elapsed time from administration of the mitostatic agent to biopsy (MI/t). Most of the malignant gliomas that had an LI of 5–15%, also yielded an MI/t value of 4–5×10−3, whereas tumors with an LI of less than 5% generally showed very slight (0.1×10−3) mitotic accumulation. Use of a mitostatic agent is suggested to differentiate the proliferative activity of various gliomas.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0533
    Keywords: Glioma ; Collagen ; Extracellular matrix ; Glycoprotein ; Mesenchyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We established and characterized five cell lines derived from human malignant gliomas (four glioblastomas multiforme and one highly anaplastic astrocytoma). All cell lines exhibited tumor cell morphology and growth kinetics, and anchorage-independent growth in soft agar. Cytogenetic analysis revealed significant aneuploidy in all five cases as well as clonal chromosomal alterations unique to each cell line. No cell line was tumorigenic in athymic mice. Two of the cell lines were sensitive to carmustine (BCNU) in monolayer and soft-agar cultures. Electron microscopy showed marked variability between cell lines in the number and structure of intracytoplasmic organelles; SF-126 formed collagen fibers in vitro. Immunohistochemical analysis of the surgical specimens showed variable expression of glial fibrillary acidic protein (GFAP) in malignant astrocytes; positive immunostaining for glycoproteins of the extracellular matrix was found predominantly in perivascular regions. In early-passage cultures, only cell line SF-295 expressed GFAP; at establishment, none of the cell lines expressed GFAF or glutamine synthetase. Fibronectin and laminin were expressed by all cell lines in early-passage culture, but expression of these glycoproteins at establishment was variable. Only SF-126 was positively identified by immunostains for procollagen III; this was also the only cell line in which DEAE-cellulose chromatography and SDS-PAGE demonstrated interstitial collagen synthesis. These well-characterized glioma-derived cell lines may now serve as useful tools with which to study the cell biology of gliomas. The synthesis of interstitial collagen by a glioma-derived cell line may suggest a derivation from vascular mesenchymal elements, either reactive or transformed, in the original heterogeneous malignant glioma, rather than from a glial precursor cell.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Meningioma ; Bromodeoxyuridine ; Cell kinetics ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ninety-six patients with intracranial meningiomas and two with hemangiopericytic variants received a 30-min intravenous infusion of bromodeoxyuridine (BrdUrd), 200 mg/m2, before tumor removal. Excised tumor specimens were stained by the indirect immunoperoxidase method to determine the BrdUrd labeling index (LI), or percentage of cells in DNA synthesis. The BrdUrd LI was 〈 1% in 63 (86.3%) of 73 nonmalignant meningiomas and 〈 1% in 20 (87%) of 23 malignant meningiomas. Of 23 malignant meningiomas 11 were recurrent tumors; 8 patients had recurrence 3 to 33 months after the study. The recurrence rate was 100% (five of five) in patients whose tumors had a BrdUrd LI 〉 5%, 44% (11 of 25) in those with a BrdUrd LI 1% to 5%, and 6.1% (4 of 66) in those with an LI 〈 1%. Thus, meningiomas with a BrdUrd LI 〉 1% may grow faster and recur more frequently. Among patients with malignant mengngiomas, the mean time to recurrence after the study was 7.5 months in those with a BrdUrd LI 〉 5% and 20.2 months for those with an LI 1% to 5%. The mean time to recurrence was 97.8 months in patients with nonmalignant meningiomas. Both hemangiopericytic variants were recurrent and showed LIs of 0.5% and 4.1%; the former tumor recurred 8 years after complete resection, while the latter recurred three times in 3.5 years. Thus, the proliferative potential of intracranial meningiomas as reflected by the BrdUrd LI appears to be a prognostic variable that can help to elucidate the biological behavior of individual meningiomas.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0533
    Keywords: Pituitary adenoma ; Monoclonal antibody Ki-67 ; Anti-DNA polymerase α monoclonal antibody ; Bromodeoxyuridine ; Nucleolar organizer regions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The growth potential of 65 pituitary adenomas was determined by histochemical analysis with Ki-67 and anti-DNA polymerase α monoclonal antibodies, bromodeoxyuridine (BrdUdR) labeling, and counts of argyrophilic nucleolar organizer regions (Ag-NORs). The mean proliferating cell indices (PCIs) determined by Ki-67 and anti-DNA polymerase α and the BrdUdR labeling index (LI) were generally very low [1.0±0.2%, 1.1±0.2%, and 0.5±0.1% (±SE), respectively]. Apart from adrenocorticotropic hormone-positive adenomas, which had significantly higher indices, there were no statistically significant differences in the indices among the other subtypes of pituitary adenomas. Recurrent tumors had higher Ki-67 and DNA polymerase α PCIs and BrdUdR LIs (3.6%, 4.2%, 1.4%) than primary tumors (0.8%, 0.8%, 0.3%; P〈0.005). The number of Ag-NORs did not correlated significantly with any of the three indices. The mean number of Ag-NORs was higher in nonfunctioning adenomas than in functioning adenomas (2.04 vs 1.66, P〈0.005); among prolactin-positive adenomas, those treated preoperatively with bromocriptine had more Ag-NORs than untreated tumors (1.75 vs 1.57, P〈0.005). These results suggest that the Ki-67 and DNA polymerase α PCIs and the BrdUdR LI predict the growth potential of individual pituitary adenomas, whereas the number of Ag-NORs appears to correlate with hormone production rather than with the proliferative potential.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0533
    Keywords: Glioblastoma ; Proliferative potential ; Bromodeoxyuridine ; Ki-67 ; Nucleolar organizer region
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To investigate intratumoral differences in indices of tumor cell proliferation, we measured the bromodeoxyuridine labeling index (BrdUrd LI), the Ki-67 protein proliferating cell indices (PCIs) determined by monoclonal antibody MIB 1 in microwave-processed paraffin sections (MIB 1 PCI) and in some eases by monoclonal antibody in frozen sections (Ki-67 PCI), and counts of argyrophilic nucleolar organizer regions (AgNORs) in 20 glioblastomas. In the most actively proliferating areas, MIB 1 and Ki-67 PCIs correlated well with the BrdUrd LI and with each other, while AgNOR counts correlated less strongly with these indices. In less active areas, the MIB 1 PCI and BrdUrd LI changed concomitantly from one area to another within a tumor except in areas of pseudopalisading with necrosis; in these areas the BrdUrd LI decreased significantly compared with neighboring tumor tissue, while the MIB 1 PCI did not. There was very little staining of gemistocytic nuclei with either anti-BrdUrd or MIB 1 monoclonal antibodies; this supports the concept that gemistocytes are mainly quiescent cells. AgNORs in all of the above-mentioned areas varied from tumor to tumor, which suggests that they may indicate some cellular activity other than proliferation. The close correlation between the BrdUrd LI and Ki-67 protein PCIs in corresponding regions of glioblastomas suggests that MIB 1 staining of microwave-processed paraffin sections can be used to evaluate the growth potential of individual glioblastomas and possibly of other gliomas as well.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0942-0940
    Keywords: Angiogenic factor bFGF ; dural AVF
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Purpose Dural arteriovenous fistulas (dAVFs) are known to be acquired disorders. Angiogenic stimulants, such as basic fibroblast growth factor (bFGF), may be involved in the evolution of this disorder. We examined the appearance and localization of bFGF, in human dAVF sinuses, versus a control using immunohistochemical techniques, to evaluate these qualitative differences. Patients and methods Four human dural sinuses from dAVF patients, and one control dural sinus were removed at surgery or autopsy and used for this study. Immunohistochemistry for bFGF was performed in all five specimens to identify its appearance and localization. Immunohistochemistry for alpha smooth muscle actin, factor VIII related antigen, and macrophage (CD-68) were done in all tissues to identify the bFGF positive cell types. Results In the control dural sinus, there was negative staining by bFGF immunohistochemistry. However, in all four sinuses of the dAVF patients, smooth muscle cells, endothelial cells, and meningeal cells were stained positively in various degrees by bFGF immunohistochemistry. Conclusion bFGF may be significant in the development of dAVFs, judging from its strong immunoreactivity in the sinuses of dAVF patients.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 18 (1968), S. 293-296 
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bericht über einen Fall, bei dem ein klinisch symptomloses Rezidiv eines chromophoben Hypophysenadenoms nachgewiesen werden konnte, weil sich ein Silberclip, der in die Tumorkapsel gesetzt worden war, nach aufwärts verlagert hatte. Die Autoren empfehlen die routinemäßige Verwendung von Silberclip als röntgenologisch sichtbare Kennmarke für alle Fälle mit Hypophysenadenom, die durch intrakranielle Operation behandelt worden sind.
    Abstract: Résumé Les auteurs rapportent un cas d'adénome chromophobe récidivant de l'hypophyse qui, bien que cliniquement asymptomatique, fut diagnostiqué par le placement vers le haut des clips d'argent placés sur la capsule de la tumeur lors de l'exérèse chirurgicale. Les clips d'argent placés sur la capsule tumorale peuvent servir de marqueurs radiographiques et leur emploi est systématiquement recommandé.
    Notes: Summary Report of a case in which a clinically asymptomatic recurrence of a chromophob pituitary adenoma was detected by the upward displacement of silver clips placed in the capsule of the tumor. The authors recommend the routine use of clips as radiographic markers for pituitary tumors treated by intracranial operation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Medicine 25 (1974), S. 83-98 
    ISSN: 0066-4219
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 7367-7371 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The time and temperature dependencies of polarization currents are investigated to higher temperatures and with greater temperature resolution than has been reported previously for zinc oxide varistors. Arrhenius plots of these transient polarization currents yield two thermal activation energies near 140 and 8 meV, which are in reasonable agreement with values reported recently, as well as an additional thermally activated level at 0.66 eV, which becomes evident in the extension of the measurements to T(approximately-greater-than)300 K. Conductance data in this higher temperature range yield the nearly identical energy of 0.68 eV for the intergranular (Schottky) barrier height. The temperature dependence of the exponent m in the power-law expression for the current-time dependence I=I0t−m was carefully examined and found to change twice from 0.5 to 1.0. The nonmonotonic behavior of m(T) can be interpreted as due to resolution of polarization currents from two different traps, each of which evolves from diffusive to dispersive transport as temperature is lowered rather than, for example, a complicated distribution of relaxation times. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
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