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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 2466-2474 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A scanning near-field optical microscope equipped with an Al-coated glass fiber tip for operation in a He cryostat is described. The instrument is designed for fluorescence detection of nanoscopic particles (single dye molecules and nanocrystallites), and allows optical imaging and spectroscopy of surfaces or thin objects with subwavelength spatial resolution at low temperatures. A shear-force control loop keeps the probing fiber tip aperture at a constant distance, i.e., a few nanometers away from the sample. The shear-force method results in a vertical stability of better than 2 nm. For light collection and confocal imaging, a transmission objective with a high numerical aperture is operated inside the cryostat. For rapid sample inspection, and in cases where no high lateral resolution or topographic imaging is necessary, the instrument can also be used without a tip as a low-temperature conventional or confocal microscope, due to the large scan range of an improved scanner. Details and characteristics of the experimental setup as well as first results are presented. First shear-force images of test patterns taken at low temperatures down to T=22 K, as well as near-field optical fluorescence images of low concentrated sulforhodamine molecules dispersed in a thin polymer film at T=75 K and room temperature, are shown. With this instrument, confocal images of CdS nanocrystallites were taken at 20 K. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 468 (1986), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 211 (1971), S. 595-616 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Impulscytophotometrie (Dittrich u. Göhde, 1969a, b) ermöglicht es, sehr genaue Mengenverteilungen (Histogramme) wichtiger Zellinhaltstoffe mit Meßraten von 1000 Zellen pro Sekunde zu ermitteln. Histogramme des DNS- und Proteingehaltes etc. lassen sich innerhalb von Sekunden bis zu wenigen Minuten gewinnen bei einer Meßgenauigkeit, die die der herkömmlichen Cytophotometer noch übertrifft. Nach geeigneter Fluorochromierung liefert die Impulscytophotometrie von Zellen des Cervical- und Vaginaismears ein- und zweiparametrige Histogramme des DNS- und Proteingehaltes. Auf eine besonders einfache Fluorochromierungs-methode der DNS von Cervical- und Vaginalzellen mit Ethidiumbromide (EB) wird hingewiesen ebenso wie auf Besonderheiten der Gewinnung und Vorbereitung des Abstrichmaterials für die Impulscytophotometrie. Seit langer Zeit wird die Frage diskutiert, ob und in welchem Umfang die Cytophotometrie der Cervical- und Vaginalsmear-Diagnostik nutzbar gemacht werden kann. Wegen ihrer großen Schnelligkeit und ihrer großen Genauigkeit ist die Impulscytophotometrie dazu angetan, diese Diskussion neu zu beleben. An über 1300 unverdächtigen Fällen wurden EB- und Feulgen-Fluorescenz-Histogramme der Cervical- und Vaginalsmearzellen impulscytophotometrisch bestimmt. Dabei zeigten sich einige auffällige Besonderheiten, u.a. das Auftreten cyclusabhängiger Nebengipfel und von kleinen Signalen, die auf das Vorhandensein von Zelltrümmern hinweisen. 4c-Zellen sind relativ selten. Die genaue Kenntnis dieser Besonderheiten des unverdächtigen Smears ist für die Beurteilung krebsverdächtiger Smears unerläßlich. Am Beispiel eines charakteristischen DNS-Histogramms bei histologisch gesichertem Carcinoma colli uteri wird auf die natürlichen Grenzen bei der Interpretation einparametriger Histogramme und auf die Möglichkeiten eingegangen, diese Grenzen durch Einführung weiterer Parameter zu überschreiten.
    Notes: Summary By the new ultra rapid method of “Impulscytophotometrie” the automatic measurement of DNA stained by fluorescent dyes became possible. The rate of measurement is more than 1000 cells per second. Cell suspension flows through a relatively large measuring area parallel to the optical axis of the microscopic objectiv. After digestion of the cellplasma of cells from cervical and vaginal smears and staining of the isolated nuclei with ethidium bromide it is possible to measure the DNA constituents. Cells with appropriate staining by fluorescent dyes emit a fluorescent light signal which is proportional to the amount of the stained compound. The light signals are amplified by photoelectrical devices and classified in a multichannel analyser. The automatically recorded DNA histograms reveal details about the proliferation kinetic of the cells, as well as of the occurrence of aneuploid and higher ploid cells. Tumourcells are having a relatively high proliferation activity. In more than 1300 unsuspect cases histograms of cervical and vaginal smear cells were performed and characteristic findings described. Furthermore shows a histogram of smear from a female patient with a carcinoma of the cervix a greater part of G2- and S-phase cells. These irregularities of tumour cell populations can be detected by the “Impulscytophotometrie”. The aim of our investigations has been to find out a basis for the automation of prescreening of vaginal and cervical smears. Further clinical work has to be done before the method works sufficiently as a prescreening method.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1434-0879
    Keywords: Proliferation of renal cell carcinoma ; Flow cytometry ; BrdUrd-labelling ; S-phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After testing the BrdUrd technique on experimental tumour cell lines, we applied the technique to human renal cell carcinoma in vitro. We compared the results with the data acquired after FCM analysis and 3H-thymidine treatment. In contrast to BrdUrd the 3H-thymidine uptake seemed to be limited in suspended cells. FCM data represented the DNA distribution of cells. BrdUrd labelling on the other hand detected DNA synthesizing cells. Only both methods in parallel were able to discriminate between proliferating cells and resting cells with an S-phase equivalent DNA content.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 239 (1971), S. 377-389 
    ISSN: 1432-069X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Impulscytophotometrie ermittelte bei 8 Hauttumoren einen höheren Anteil von Zellkernen mit erhöhtem DNS-Gehalt als bei Kontrollgeweben (Vollhaut, Lymphknoten und Zengenschleimhaut). Die DNS-Histogramme, welche jeweils 50000–200000 Zellkerne repräsentieren, korrespondierten in wesentlichen Einzelheiten den klinischen und histologischen Befund. Das neuartige Meßverfahren der Impulscytophotometrie erlaubt bei großer Genauigkeit jeder einzelnen Messung wegen der hohen Geschwindigkeit des Meßablaufs Untersuchungen an einer Vielzahl von Tumoren in kürzester Zeit.
    Notes: Summary In eight samples of skin tumours a greater number of nuclei with an increased DNA content as compared to controls (normal skin, lymph nodes and periglottis) were found by pulse cytophotometry. DNA histograms—each histogram representing 50.000–200.000 nuclei—are predominantly in good correlation with the clinical and histological findings. With the new method of pulse cytophotometry it is possible to obatin DNA histograms of a great number of tumours in a short time with a high degree of accuracy.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 61 (1979), S. 249-254 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Methods are given for the preparation and staining of human spermatozoa for flow cytometric DNA measurements. Using agents for the reductive cleavage of disulfide crosslinks and suitable proteolytic enzymes and effective decondensation of the sperm chromatin and a DNA-proportional uptake of fluorochromes is achieved. Thus reliable and precise measurements of the relative DNA content of human spermatozoa are possible and the two subpopulations of haploid spermatozoa can be distinguished according to the difference in their DNA content.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 49 (1971), S. 1090-1092 
    ISSN: 1432-1440
    Keywords: Pulse cytophotometry ; DNA-content ; cell kinetics ; leukemia ; virus infection ; Impulscytophotometrie ; DNS-Gehalt ; Zellkinetik ; Leukämie ; Virusinfekt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der Impulscytophotometrie bietet sich jetzt eine Methode für die hämatologische Diagnostik, die innerhalb von wenigen Minuten Daten über die Proliferationskinetik, im besonderen über den Anteil der G1-Phasezellen, S-Phasezellen und (G2+M)-Phasezellen an der Gesamtpopulation sowie über aneuploide Stammzellinien schnell und genau liefert.
    Notes: Summary The “impulse cytophotometry” contributes considerably to the haematological diagnosis, producing within a few minutes data about the proliferation kinetics. Quick and correct assessment of G1-phase cells, S-phase cells and (G2+M)-phase cells as well as data on aneuploid cell stemlines is thus facilitated.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1335
    Keywords: Key words DNA/protein flow cytometry ; Bronchial washing fluid ; Cytology ; Early diagnosis ; Lung cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study was performed to improve early lung cancer diagnosis in bronchial washing fluid, thereby increasing the diagnostic sensitivity of bronchoscopy by means of high-resolution flow cytometry (FC). We combined dual-parameter DNA/protein FC and conventional cytology in bronchial washing fluid samples from 112 patients with neoplastic and non-neoplastic lung diseases and found 43% of histologically confirmed tumor cases to be cytologically positive; 63% of the tumor samples were aneuploid, 52% of the aneuploid cases were cytologically positive and 48% were negative. In the negative cases, FC was an independent diagnostic factor. In 32% of the cases, FC also failed to detect abnormalities. However, the combination of both techniques increased the sensitivity in detecting neoplastic cells to 73%. Furthermore, simultaneous DNA/protein analysis allowed the recognition of aneuploid cell lines not detectable by single DNA measurement. Identification of aneuploid subpopulations by dual-parameter analysis in cytologically negative one-parameter FC “diploid” samples assumes an important diagnostic value. Dual-parameter DNA/protein FC is a valuable technique that increases the diagnostic yield of bronchoscopy with no risk for the patient and a low additional cost.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 252 (1970), S. 328-330 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mit Hilfe der Impulscytophotometrie (Impulsfluorimetrie) lassen sich neben 1-parametrigen Histogrammen durch simultane Messung zweier unterschiedlicher Zellinhaltsstoffe auch 2-parametrige Histogramme automatisch gewinnen. Dies wird für die DNS- und Proteinsynthese anhand der Wirkung des Cytostaticums VELBE auf Populationen von Ehrlich-Ascites-Tumorzellen demonstriert. VELBE hemmt den Ablauf der Mitosen, blockiert aber in cytostatisch bereits deutlich wirksamen Konzentrationen die DNS-Synthese keineswegs vollständig, so daß durch Endomitose vermehrt tetraploide Zellen auftreten. Auch die Proteinsynthese der Zellen wird außerhalb der Mitose durch VELBE offenbar nicht primär gehemmt.
    Notes: Abstract By the method of impulse cytophotometry (impulse fluorometry) not only histograms of one-parameter but also those of two-parameters can be obtained automatically by simultaneous measurement of two different cell substances. This is demonstrated for DNA and protein content per cell in populations of Ehrlich ascites tumour cells in vivo after treatment with vincaleucoblastine sulphate (VELBE). VELBE inhibits the mitosis. However, in low concentrations which may have a pronounced cytostatic effect VELBE will not stop completely the DNA synthesis, and therefore by endomitosis more tetraploid cells can appear. Evidently, in low concentrations and beyond the mitosis VELBE does not primarily inhibit the synthesis of cell proteins.
    Type of Medium: Electronic Resource
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