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  • 1
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 259-259 
    ISSN: 0730-2312
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Two methods have emerged for measuring the DNA content of paraffin-embedded tissue using image cytometry: (1) analysis of thin sections, and (2) analysis of nuclei extracted from thick sections. These methods were evaluated using 31 breast tumors for which paraffin-embedded material was available. Cases selected represented 11 diploid, 11 tetraploid, and 9 aneuploid tumors. Results generated using image cytometry methods were compared with those obtained using flow cytometry. For thin sections, the tissue correction feature of the CAS 200 Image Cytometer was used to estimate the DNA content of whole nuclei from measurements made on sectioned nuclei. DNA histograms were generated from tissue sections cut at the same microtome setting (5 μm) before and after software corrections of 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, and 7.5 μm. A comparison of flow cytometry and thin-section image analysis in the absence of tissue correction showed 90% concordance for diploid, 27% concordance for tetraploid, and 77% concordance for aneuploid tumors. The ploidy estimated on thin sections by at least one of the correction values was discordant in 72% of diploid, 91% of tetraploid, and 78% of aneuploid tumors. For cell nuclei extracted from paraffin, excellent agreement was found between flow and image cytometry (r = 0.933). It was concluded that in most cases, cell nuclei extracted from paraffin are preferable to tissue sections for ploidy analysis of breast tumors using image cytometry.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 81-88 
    ISSN: 0730-2312
    Schlagwort(e): Breast fine needle aspiration ; cytopathology ; ductal carcinoma in situ ; HER-2 ; lobular carcinoma in situ ; ploidy analysis ; proliferation markers ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Fine needle aspiration (FNA) of the breast is a well-tolerated procedure used to evaluate palpable breast masses, has a reported mean specificity of 99%, and a reported sensitivity of 70-99%. The false positive rate varies from 0-0.4% in most larger series, with a reported false negative rate ranging from 0.7-22%; however, higher false negative rates have been reported in tumors under 2 cm in diameter. The FNA technique uses a fine, 20 gauge or less, needle and is not associated with a significant risk of tumor growing out the needle tract.FNA cytology is not effectively used if a breast mass cannot be palpated or distinguished from fibrous tissue within the breast. The procedure can be applied to nonpalpable masses detected by mammography by employing stereotactic techniques. The cytologic samples obtained from FNA can be used to distinguish atypical ductal hyperplasia from in situ or invasive ductal carcinoma; however, cytologic criteria to effectively distinguish ductal carcinoma in situ (DCIS) from invasive adenocarcinoma are not definitive in many cases, and are dependent on variables related to the type of intraductal tumor, the size and character of the cell groups, and the presence of single or disaggregated tumor cells. Employing current cytologic criteria, lobular carcinoma in situ (LCIS) may be distinguished from invasive lobular carcinoma in some cases; however, the individual LCIS cells are not morphologically distinct from lobular carcinoma cells. Atypical lobular hyperplasia has cellular features essentially the same as those seen in LCIS.Needle biopsy (NB) employs larger needles of 14-16 guage. Stereotactic guidance for NB can be augmented with cytopathology by preceding the biopsy with FNA, and/or by collecting the cellular sample available when washing the needle after the tissue sample is removed. These needle biopsy washings are often highly cellular and are complementary to the tissue diagnosis.FNA samples or NBs, if adequately cellular, are applicable for DNA analysis by static image analysis (flow cytometry). Flow cytometry is of limited practical value where cellularity or tumor representation is poor because morphologic confirmation cannot be established. These samples can also be used to calculate tumor proliferative fraction, employing Ki-67 antigen. Quantitation of nuclear organizer (AgNOR) regions and expression of HER-2/neu and p53 proteins can be accomplished in these samples; estrogen and progesterone receptors can also be detected and quantitated.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 135-144 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Redundancy in the simplest form of a two-dimensional TLM network is identified and a method of eliminating it is described. Results obtained using the non-redundant algorithm are compared with those derived from the standard, redundant algorithm. The non-redundant approach is extended to deal with non-uniform elemental capacitance; a cylindrical geometry is taken as an example of this. The scope for and benefits of rendering TLM diffusion models non-redundant are discussed.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 0197-8462
    Schlagwort(e): skin ; mouse ; tumor promotion ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Physik
    Notizen: This paper describes preliminary findings on the influence of 60-Hz (2-mT) magnetic fields on tumor promotion and co-promotion in the skins of mice. The effect of magnetic fields on natural killer (NK) cell activity in spleen and blood was also examined. Groups of 32 juvenile female mice were exposed to the magnetic field as described in part I. The dorsal skin of all animals was treated with a subthreshold dose of the carcinogen 7, 12-dimethylbenz(a)anthracene (DMBA). One week after the treatment, two groups were sham exposed (group A) or field exposed at 2 mT (group B) 6 h/day for 21 weeks, to test whether the field would act as a tumor promoter. No tumors developed in these two groups of mice. To test whether the magnetic field would modify tumor development by directly affecting tumor growth or by suppressing immune surveillance, two additional groups of mice were treated weekly with the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) and then either sham exposed (group C) or field exposed (group D). The time to appearance of tumors was shorter (but not statistically so) in the group exposed to magnetic fields and TPA. Some differences in NK cell activity and spleen size were observed between the sham- and field-exposed groups.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    BioEssays 15 (1993), S. 499-505 
    ISSN: 0265-9247
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Recent work has shown that segmentation underlies the patterning of the vertebrate hindbrain and its neural crest derivatives. Several genes have been identified with segment-restricted expression, and evidence is now emerging regarding their function and regulatory relationships. The expression patterns of Hox genes and the phenotype of null mutants indicate roles in specifying segment identity. A zinc finger gene Krox-20 is a segment-specific regulator of Hox expression, and it seems probable that retinoic acid receptors also regulate Hox genes in the hindbrain. The receptor tyrosine kinase gene Sek may mediate cell-cell interactions that lead to segmentation. These studies provide a starting point for understanding the molecular basis of segmental patterning in the hindbrain.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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