摘要:

SUMMARYThe application of assumption‐free, unbiased stereological techniques for estimation of the volume‐weighted mean nuclear volume, nuclear v̄V, from vertical sections of benign and malignant nuclear aggregates in melanocytic skin tumours is described. Combining sampling of nuclei with uniform probability in a physical disector and Cavalieri's direct estimator of volume, the unbiased, number‐weighted mean nuclear volume, nuclear v̄N, of the same benign and malignant nuclear populations is also estimated. Having obtained estimates of nuclear volume in both the volume‐and number distribution of volume, a detailed investigation of nuclear size variability is possible. Benign and malignant nuclear populations show approximately the same relative variability with regard to nuclear volume, and the presented data are compatible with a simple size transformation from the smaller benign nuclei to the larger malignant nuclei. Finally, the variance in the volume distribution of nuclear volume is estimated by shape‐independent estimates of the volume‐weighted second moment of the nuclear volume, ***v̄2v, using both a manual and a computer‐assisted approach. The working procedure for the description of 3‐D size variability within benign and malignant nuclear populations can for all practical purposes be reduced to 2‐D measurement of nuclear profile areas. These new powerful stereological estimators of nuclear volume and nuclear size variability provide an attractive approach to quantitative and reproducible malignanc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03132.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYA simple approximative stereological method is proposed for obtaining the fundamental parameters of a three‐dimensional Boolean model. It uses serial sections for the determination ofN+V, the specific convexity number. This procedure was applied to two different examinations of bread, which can be very well described by Boolean model

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03133.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYA versatile program is described for a BBC‐ or IBM‐compatible microcomputer, which uses a fast Fourier transform in calculating diffraction‐limited microscopic images. The defined ‘object’ can be a diffraction grating or a discrete specimen seen in cross‐section, of arbitrary interval (or width), transmittance and retardation. Many microscopical techniques can be simulated including bright‐field, phase contrast, central and peripheral dark‐field, schlieren, apodization, fluorescence, differential interference contrast and confocal scanning. Instrumental settings which can be varied include the aperture, focus and primary spherical aberration of the objective, the coherence and obliquity of the illumination, and in phase contrast the width, transmittance and retardation of the phase plate. The Fourier transform and various other algorithms used in the progra

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03134.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYAn imbalance of potassium in cardiac muscle causes an alteration of heart function. The distribution and concentration of potassium in rat papillary heart muscle was studied using cryofixation and X‐ray microanalysis. Freeze‐dried cryosections and sections of freeze‐dried, embedded tissue were analysed. Bulk frozen specimens were freeze‐dried either in a vacuum or by a new technique using liquid propane as a cryodehydration medium. These two methods of freeze‐drying were tested for elemental retention in other specimens, with comparable results. A potassium concentration of 120 mmol/l was measured in normal myocytes of cardiac papillary muscle compared to 80 mmol/l in myocytes of animals stressed by a temperature of 45°C for 1 h. The presumed physiological significance of the findings is

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03135.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYIn this paper we suggest a new statistical method of correcting the results of hot‐line experiments for the effects of background sources and we use the new method to reassess the adequacy of three probability distributions proposed in the literature for image spread from line sources. The data are from sources labelled with125I in semi‐thin resin sections 0·4‐0·8 μm in thickness. The new method reveals that two of the models describe the empirical distributions more closely than earlier analysis had suggested, and it confirms an increasing relationship between half distance of image spread and the thickness of the source. However, it also confirms that considerable ‘inter hot‐line’ experimental variation remains, even after background correction. This suggests that multiple experiments are needed to produce reliable estimates of

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03136.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYExtended energy‐loss fine‐structure spectroscopy (EXELFS) and electron energy‐loss spectroscopy (EELS) microanalysis have been used to study the structural and chemical modifications caused by interaction with the atmosphere of small, very reactive chromium (Cr) particles whose diameters range from 150 to 1300 Å.Analysis of the data allows us to deduce that the particles consist of a Cr core with a body‐centred cubic structure and with a lattice parameter reduced by about 4% with respect to the bulk value by surface stresses (for the smallest diameter), surrounded by a Cr2O3shell of about 15

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03137.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYSperm quality has been studied using different microscopic methods. Light microscopy gives similar percentages of sperm typologies (mature, immature and aberrant) as scanning electron microscope (SEM) techniques using both normal (critical‐point drying) and simple desiccation techniques. Artefactual forms, which are easily recognizable, are not taken into account. The artefactual forms observed by the simple desiccation SEM method were spermatozoa with tails folded in a simple loop, and spermatozoa with short tails coiled at their extreme. The simple desiccation SEM method is a useful and rapid technique for the testing of porcine sperm qualit

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03138.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SUMMARYA new technique for the visualization of DNA‐containing structures in electron microscopy is described. Samples of glutaraldehyde‐fixed bone marrow from rats were subjected to alkaline hydrolysis to remove RNA and the phosphate of phospho‐proteins, followed by a combined blockage of protein carboxyl and amino groups through methylation‐acetylation. After uranyl acetate staining of epoxy‐embedded ultrathin sections, chromatin from all cell types showed a highly selective and intense electron opacity. Staining methods for DNA were also positive in semithin sections. This simple procedure could be very useful in ultrastructural cytochemistry of DNA and

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03139.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Book reviewed in this article:Stereology of Objects with Internal Structure. By Ivan Saxl.Microprobe Analysis in Medicine. Ultrastructure in Pathology Publication Series. Ed by P. Ingram, J. D. Shelburne, V. L. Roggli (Consulting Editors: J. V. Johannessen and V. E. Gould).R.M.S. Microscopy Handbook No. 18: Autoradiography: A Comprehensive Overview. By John R. J. Baker.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1991.tb03140.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY