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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 3955-3961 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A dynamic force distance control for scanning near-field optical microscopy (SNOM) based on a quartz tuning fork as piezoelectric force sensor is introduced. In contrast to a similar design for shear-force feedback, the tuning fork is aligned in such a way that forces perpendicular to the surface are detected. Various near-field probes can be attached to the end of the tuning fork and serve as force sensing tip. The high force sensitivity is demonstrated for two different near-field probes by imaging the topography of organic samples. The tetrahedral tip, an apertureless high-resolution near-field probe used up to now mainly with tunnel current distance control, is for the first time successfully combined with a force distance control for SNOM. A similar distance control was used in conjunction with an only few millimeters short aluminum-coated tapered fiber tip as near-field probe. The suitability of this design for near-field optical fluorescence imaging is demonstrated. Furthermore, the dynamic force distance control with a fiber tip was applied to a soft biological sample under water. The force sensitivity turned out to be sufficiently high to reveal corrugations in the order of 1 nm. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 3868-3870 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The compositional analyses of InxGa1−x/GaAs (001) island structures grown by molecular beam epitaxy at a substrate temperature of 560 °C with nominal In contents of x=60% and 100% are presented on the basis of high resolution transmission electron microscopy micrographs. The linear dependence of the lattice parameter on the In content (Vegard's law) is exploited to quantitatively derive composition profiles on an atomic scale by measuring local lattice parameters and displacements. The relaxation of the thin transmission electron microscopy specimen is taken into account by the accurate thickness determination using the quantitative analysis of the information from transmission electron micrographs procedure. The final evaluation step consists of finite element modeling with the appropriate sample geometry, where the In distribution is chosen to obtain the best fit between experimental and simulated displacements. The observed In content is significantly smaller than the nominal In concentration which is due to segregation of In and diffusion of Ga from the GaAs buffer into the island during the growth. The measured mean In concentration of the islands with a nominal In content of 60% (100%) is 24% (45%). © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 53 (1998), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Pillar cells are important to maintain the structural integrity of the fish gills. This study describes a new monoclonal antibody (mab 25) which detects a complex tubular structure of rainbow trout Oncorhynchus mykiss gill pillar cells. This mab was selected and established after immunization of mice with density gradient separated trout mononuclear cells. In primary screening using a cell enzyme-linked immunoabsorbant assay (ELISA) the corresponding hybridoma supernatant reacted with viable and fixed trout leukocytes. In immunofluorescence analysis mab 25 showed a distinct reaction with a prominent snow chain like tubular structure in pillar cells. It consists of seven to 11 concave turned tubuli of about 5 μm length forming a circle of about 7 μm. Reactivity of mab 25 with fibrous structures was observed in cryostat sections of gill, pseudobranchia, spleen, striated muscle and heart muscle. mab 25 recognized a protein with a molecular weight of about 58 kDa as determined by radioimmunoprecipitation. This structure appears to be related to elements which have been described as membrane enclosed collagen columns by electronmicroscopic analysis and is reminiscent of patterns labelled with anti-human cytokeratin antibodies. mab 25 may be an important tool to study the impact of environmental and physiological conditions on the structural integrity of this complex structure in trout gill pillar cells.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 36 (1997), S. 355-355 
    ISSN: 1436-6215
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1433-0385
    Keywords: Key words: Breast carcinoma ; Magnetic resonance mammography ; Breast preservation ; Impact on ; Schlüsselwörter: Mammacarcinom ; Magnetresonanzmammographie ; brusterhaltende Operation ; Einfluß auf das operative Vorgehen.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Einleitung: In einer prospektiven Studie wurden der diagnostische Stellenwert sowie der Einfluß der Magnetresonanzmammographie (MRM) auf das operative Vorgehen bei Patientinnen (n = 125) geprüft, bei denen aufgrund der klinischen, sonographischen oder mammographischen Untersuchung der Verdacht auf ein Mammacarcinom bestand. Diese Patientinnen wurden zusätzlich einer bilateralen MRM zugeführt. Besonderes Interesse bestand hinsichtlich der Erkennung multifocaler, multizentrischer und kontralateraler Läsionen. Methode: Nach kompletter operativer Entfernung aller diagnostizierten Läsionen erfolgte die Ermittlung von Sensitivität und Spezifität der diagnostischen Methoden sowie einer Korrelation zwischen den apparativen und den histologischen Befunden. Ergebnisse: Bei 112 Patientinnen lagen vollständige Daten für die Auswertung vor: Allein mit Hilfe der konventionellen Verfahren wurden 91 Malignome entdeckt; dabei betrug die Sensitivität/Spezifität für die klinische Untersuchung 73 % bzw. 67 %, für die Mammasonographie 58 % bzw. 86 % und für die Röntgenmammographie 89 % bzw. 20 %. In diesem vorselektionierten Patientinnenkollektiv (Prävalenz 81,25 %) wurden durch die MRM die bereits durch konventionelle Verfahren entdeckten Läsionen mit einer Sensitivität von 96,7 % und einer Spezifität von 19 % bestätigt. Darüber hinaus wurden durch die MRM 46 weitere suspekte Läsionen diagnostiziert. Es fanden sich histologisch 28 maligne (25 ipsilaterale multifocale oder multizentrische Läsionen, 3 kontralaterale Carcinome) und 18 benigne Tumoren. Die Rate falsch-positiver MRM-Befunde lag bei 18 %. Aufgrund der MRM-Befunde wurde in 14,3 % der Fälle anstatt des ursprünglich geplanten brusterhaltenden Verfahrens eine Mastektomie durchgeführt. Schlußfolgerung: Anhand unserer Untersuchungsergebnisse ist die MRM das Verfahren der Wahl in der Differentialdiagnose diskrepanter Befunde von Mammographie und Sonographie und stellt die sensitivste Methode zum Ausschluß einer Multifocalität oder Multizentrizität dar. In unserem Patientinnenkollektiv beeinflußten die Befunde der MRM die Planung des operativen Vorgehens erheblich. Für den sinnvollen Einsatz der Methode sind ein hoher technischer Standard sowie eine hohe Qualifikation des Untersuchers und eine enge interdisziplinäre Kooperation zwischen Radiologen, Pathologen und Chirurgen Voraussetzung.
    Notes: Summary. Introduction: In a prospective study the diagnostic validity of magnetic resonance mammography (MRM) as well as its impact on the choice of the operative procedure in the treatment of breast cancer was examined. In 125 patients who were suspected of having breast cancer by clinical examination, ultrasound, and X-ray mammography, additional bilateral MRM was performed. Of special interest was the diagnostic potential of MRM with regard to multifocal, multicentric and contralateral lesions. Methods: After a complete resection all lesions diagnosed by the various conventional methods were examined pathohistologically. In 112 patients, complete data were available to calculate the sensitivity and the specificity of each method as well as to correlate its results with the pathohistological findings. Results: In 91 cases, a breast carcinoma was diagnosed by conventional methods, with a sensitivity/specificity of 73 %/67 % for clinical examination, of 58 %/86 % for ultrasound, and of 89 %/20 % for X-ray mammography. In this preselected series of patients with a prevalence of 81.25 % the diagnosis established by the various methods was confirmed by MRM with sensitivity of 96.7 % and specificity of 19 %. Forty-six additional suspicious lesions were found only by MRM, of which 28 were malignant (25 multifocal or multicentric and 3 contralateral carcinomas), and 18 benign. The rate of false-positive MRM results was 18 %. Due to the MRM findings, the therapeutic procedure was changed from breast preservation to mastectomy in 14.3 %. Conclusion: Not only for the differential diagnosis of discrepant findings between X-ray mammography and ultrasound, but especially for the diagnosis of multifocal or multicentric lesions, MRM seems to be the method of choice. Consequently, MRM plays an important role in planning the operative procedure in breast cancer patients, especially in the context of breast preservation. To ensure optimal use of this new diagnostic tool high technical standards, proper expertise on the part of the examining radiologist, and effective cooperation among the involved disciplines (radiology, pathology, surgery) must be guaranteed.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1289
    Keywords: Schlüsselwörter Lebertumoren ; Therapie ; Lebertumoren ; benigne ; Hämangiom ; Leber ; Fokal noduläre Hyperplasie ; Leber ; Leberadenom ; Präkanzerose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zum Thema Durch Sonographie, Farb-Doppler-Technik, Computer- und Magnetresonanztomographie sowie szintigraphische Methoden gelingt in aller Regel eine gute Differenzierung der häufigsten benignen Lebertumoren. Ergänzt wird diese natürlich durch klinische und humorale Untersuchung unter Einschluß von Tumormarkern, um die Verdachtsdiagnose maligne oder benigne zu untermauern. Die Biopsie sollte weitgehend vermieden werden, da die meistens sichere Diagnostik eindeutig nichtmaligner Strukturen durch die genannten Verfahren möglich ist und malignitätsverdächtige Strukturen ohnehin eine Operation notwendig machen, sofern der Zustand des Patienten dies erlaubt. In dieser Arbeit werden nur die benignen soliden Lebertumoren behandelt, nicht die (poly-)zystischen, parasitär zystischen Lebererkrankungen und Abszesse.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1084
    Keywords: Key words: Carcinoma of the breast ; MR imaging ; Prognostic factors ; Histopathology ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The objective of this study was to evaluate the prognostic value of contrast-enhanced MR mammography in patients with breast cancer. A total of 190 patients with breast cancer (37 noninvasive carcinomas, 153 invasive carcinomas) underwent dynamic contrast-enhanced MR mammography preoperatively. Using 1.5-T unit, T1-weighted sequences (2D FLASH) were obtained repeatedly one time before and five times after IV administration of 0.1 mmol gadopentetate-dimeglumine per kilogram body weight. The findings on MR imaging were correlated with histopathologically defined prognostic factors (histological type, tumor size, tumor grading, metastasis in lymph nodes). In addition, immunohistochemically defined prognostic factors (c-erbB-1,c-erbB-2, p53, Ki-67) were correlated with the signal increase on MR mammogram in 40 patients. There was no significant correlation between the findings on MR mammography and the histopathological type of carcinoma, the grading, and the lymphonodular status. Noninvasive carcinomas showed a higher rate of moderate (38 %) or low (27 %) enhancement on MR imaging than invasive carcinomas (6 and 3 %). The results on MR mammography and the results of immunohistochemical stainings did not correlate significantly. Noninvasive carcinomas showed significantly lower enhancement than invasive carcinomas. However, the signal behavior of contrast-enhanced MR mammography is not related to established histopathological prognostic parameters as subtyping, grading, nodal status, and the expression of certain oncogenes/tumor suppressor genes.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 37 (1997), S. 692-701 
    ISSN: 1432-2102
    Keywords: Key words Carcinoma of breast • Contrast-enhanced MR imaging of breast • MR imaging-guided intervention • Preoperative localization • Percutaneous biopsy • MR imaging-compatible needle equipment ; Schlüsselwörter Mammakarzinom • Dynamische MR Mammographie • MRT-gestützte Intervention • Pröoperative Lokalisation • Perkutane Biopsie • MRT-kompatible Punktionsmaterialien
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Suspekte Herdbefunde in der dynamischen MR Mammographie, die mit anderen bildgebenden Verfahren nicht darstellbar sind, könnnen durch MRT-gestützte Interventionen weitergehend bioptisch abgeklärt oder präoperativ markiert werden. Die vorliegende Arbeit gibt einen Überblick über die Möglichkeiten sowie Vor- und Nachteile der von verschiedenen Arbeitsgruppen verwendeten Punktionsvorrichtungen. Weiterhin wird die Palette der derzeit zur Verügung stehenden Punktions- und Markierungsmaterialien präsentiert. Hinsichtlich der suszeptibilitätsbedingten Signalveränderungen kommen hierbei insbesondere der Nadelangulierung und der Sequenzwahl eine entscheidende Bedeutung zu. Zusätzlich zur Illustration repräsentativer Kasuistiken wird das Procedere bei speziellen Problemfällen (Multizentrischer Tumornachweis, bilateraler Tumornachweis) diskutiert. Hinsichtlich der Dokumentation der kompletten Herdentfernung nach MRT-gestützter präoperativer Markierung hat sich die Kontrolluntersuchung innerhalb der ersten postoperativen Woche als sinnvoll erwiesen. In der eigenen Abteilung wurden bisher 174 MRT-gestützte Interventionen durchgeführt. Hierbei ergaben sich bei 36 perkutanen Biopsien zytologisch bzw. histologisch in 67 % der Fälle gutartige und in 25 % der Fälle bösartige Veränderungen. Bei 3 Patienten war das Biopsat insuffizient. Bei 136 MRT-gestützten präoperativen Lokalisationen ergab die histologische Aufarbeitung des Präparates in 51 % einen benignen und in 49 % einen malignen Befund. In 3 Fällen wurde die suspekte Läsion durch den Chirurgen primär nicht entfernt. MRT-gestützte Interventionen der Mamma werden an der Universität Göttingen inzwischen routinemäßig durchgeführt.
    Notes: Summary If suspicious lesions found with MR imaging cannot be visualized by either mammography or ultrasound, MR imaging – based guidance systems are needed to guide needle biopsy or to allow localization of the lesion before surgery. The authors give an overview of the advantages and disadvantages of biopsy devices presented by different working groups. Furthermore, MR-compatible needle equipment for interventions of the breast is demonstrated. The angulation of the needle and the type of sequence are the most important factors for signal loss due to susceptibility. The strategy in special problem cases (multicentricity, bilateral lesions) is discussed. Control MR imaging within the first week after open biopsy is the best way to document the complete excision of a suspicious hypervascularized lesion after MR-guided wire localization. At our institute, percutaneous biopsy (36 interventions) revealed benign findings in 67 % and malignant lesions in 25 % of cases. Three biopsies were insufficient. Histology after MR-guided wire localization (136 interventions) showed benign findings in 51 % and malignancy in 49 % of cases. The suspicious lesion was missed by the surgeion in three cases. We perform MR-guided interventions of the breast routinely in indicated cases.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1041
    Keywords: Key words Fluoroquinolones ; Topical application ; Aque-ous humor penetration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: A prospective study was undertaken to determine the transcorneal penetration of three topically applied fluoroquinolones into aqueous humour. Methods: Two hundred and twenty-four patients undergoing cataract extraction received 0.3% ciprofloxacin, norfloxacin or ofloxacin eye drops by two different administration modes with different frequencies and intervals of application. At the beginning of cataract extraction (0.5–3 h after the last drop), 50–100 μl aqueous fluid was aspirated from the anterior chamber and immediately stored at −80 °C. Antibiotic concentrations were measured using high-performance liquid chromatography. Results: Generally, topical ofloxacin and ciprofloxacin yielded aqueous humour levels higher than topical norfloxacin. The highest concentrations of all tested fluoroquinolones were measured after using an application mode, in which one drop was given every 15 min between 0600 hours and 0800 hours, prior to operation. When applied by this mode, ciprofloxacin achieved a mean aqueous level of 0.380 (±0.328) μg · ml−1 (range 0.033–1.388 μg · ml−1), norfloxacin 0.182 (0.118) μg · ml−1 (range 0.038–0.480 μg · ml−1) and ofloxacin 0.564 (0.372) μg · ml−1 (range 0.064–1.455 μg · ml−1). These mean concentrations were above the minimum inhibitory concentration (MIC90), concentrations required for inhibition of 90% of pathogen strains in vitro of gram-negative bacteria, such as Proteus mirabilis and Escherichia coli. Therapeutic values above the MIC90 of Staphylococcus epidermidis, the pathogen causing eye infections most frequently, were reached by 67.5% of patients after ofloxacin and by 41% after ciprofloxacin, but never after norfloxacin treatment. Conclusion: Of the currently available topical fluoroquinolones, ofloxacin achieved the highest aqueous humour concentration. This fluoroquinolone may be an useful ophthalmic agent for topical antibacterial management, but it does not seem to be prophylactically effective against Streptococcus pneumoniae or Pseudomonas aeruginosa.
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