摘要:

AbstractFor fundamental reasons, fluorescence microscopes are more limited in axial, as opposed to transverse, resolution. By giving the excitation field a particular axial structure, this limitation can be partially alleviated, as in confocal scanning or two‐photon scanning, or even in optical sectioning microscopy in cases where the object occupies only a small part of the field of view. Standing‐wave fluorescence microscopy (SWFM) is a direct imaging method in which the specimen is excited by a 3‐D field of planar interference fringes oriented parallel to the object focal plane of the microscope. By shifting the position of the nodal planes of this field relative to the specimen, structures that are normally obscured under uniform excitation become resolved. We demonstrate that, in very thin biological specimens, thisoptical subsectioningincreases axial resolution by an order of magnitude, to 0.04 μm. In comparison to confocal scanning, SWFM resolves fine axial structure with more than 10‐fold greater speed, and with similarly‐reduced photobleaching. We also discuss the more general case of excitation field synthesis (EFS), in which standing wave fields differing in node spacing can be overlapped or time‐multiplexed in the specimen so that the average field is non‐periodic and peaked at the object focal plane. A transfer function model is given to show that for weakly‐refractive specimens of arbitrary thickness, such as single cells or cell monolayers, EFS should lead to a fivefold improvement in

ISSN:0966-9051    

DOI:10.1002/1361-6374(199312)1:4<187::AID-BIO1>3.0.CO;2-P

出版商:IOP Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA method is presented which allows accurate automatic quantification of the protective effect of drugs in cardiomyocytes. Isolated myocytes, obtained by enzymatic digestion of heart tissue by collagenase, are kept in petri dishes which can be mounted on a microscope table. Test compounds are added to the medium. Light intensity settings and focus positions are automatically adjusted, and a number of consecutive images is acquired by scanning the stage with stepper motors, capturing frames, and storing the (pre‐)images on disk. After applying a pathological stimulus to the cells, cardiomyocytes display an irreversible hypercontracture from rod‐ to round‐shaped cells. The same fields (post‐images) are captured again and also stored. After image segmentation and labeling, corresponding cells in the pre‐ and post‐images are measured and classified into ‘rod‐’ and ‘round‐shaped’ groups. Finally, the protection factor is calculated as the percentage of cells remaining rod‐shaped after the stimulus (survival fraction). This value is printed together with a composite image of the selected cells before and after aggression for archiving and quality control. The protection factors are evaluated to select promising cardioprotective drugs. Protection values are incorporated into a database for pharmacological information retrieval, and can be further used for determining structu

ISSN:0966-9051    

DOI:10.1002/1361-6374(199312)1:4<197::AID-BIO2>3.0.CO;2-L

出版商:IOP Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractDeconvolution techniques are often used in the processing of optical section data. In this paper, we examine whether this approach is appropriate. We propose criteria that an ideal filter should meet. We find a filter meeting our criteria for the microscopy of incoherently illuminated samples and examine its performance on simulated data.

ISSN:0966-9051    

DOI:10.1002/1361-6374(199312)1:4<207::AID-BIO3>3.0.CO;2-O

出版商:IOP Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractDiffraction by a well ordered striated muscle fibre is discussed using both rigorous numerical methods and approximate analytic formulae. It is shown that many previous predictions can be reproduced in a simple manner using ideas developed in the area of volume holography. Concepts such as optical ‘thickness’ and ‘thinness’ can be used to decide the diffraction regime of the muscle (Bragg/Thick, Intermediate, or Raman‐Nath/Thin). Appropriate approximate models can then be derived to predict the resulting diffraction efficiencies and phases. Coherent images, produced using the scatter function formalism, are presented for three types of mus

ISSN:0966-9051    

DOI:10.1002/1361-6374(199312)1:4<214::AID-BIO4>3.0.CO;2-T

出版商:IOP Publishing Ltd    

年代:1993

数据来源: WILEY