摘要:

SUMMARYThe accurate estimation of stereological parameters defined on anisotropic structures is a long‐standing problem. In this paper we seek to estimate the capillary length densityJvin skeletal muscle tissue. A well‐known model for directional anisotropy in space, namely the ‘spherical normal’ or ‘Fisher axial distribution’ model, is found to fit the relevant data satisfactorily. Based on this model, a short‐cut estimation method is proposed and illustrated with a numerical example. This method essentially consists in taking the ratio of mean capillary profile counts, as obtained from transversal and longitudinal sections of the muscle tissue, and making use of a table or a graph given in the paper to estimateJv.The conditions under which the methods are applicableandpracticable are discussed in detail. Apart from an accurate estimation ofJv, an important feature of our method is the possibility of quantifying the degree of anisotropy by a coefficientK(called theconcentration parameterof the Fisher axial distribution), which enjoys both a biological significance and a sound stat

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04240.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYThis paper provides additional experimental evidence that biological variation between individuals is likely to be the major factor influencing the overall precision and efficiency of nested sampling schemes for morphometric analysis of thin sections.Four distinct experimental systems (two based on nervous tissue and two on epithelia) have been investigated. Morphometric estimates were obtained from measurements made on micrographs generated by sampling tissues at several levels. Sources of sampling variation were isolated so that the contributions to overall variance made by inter‐animal differences could be evaluated.In each case, biological variation was the cardinal component of total observed variance between animals. Relative contributions ranged from 53% to 78%. Examining more animals would be the most efficient way of reducing the variance of the group mean in these sampling design

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04241.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYAdult male mice were exposed for periods of up to 7 days at atmospheric pressures of either 72 or 52 kPa (540 or 390 mm mercury). Changes in body weights, spleen weights and red and white splenic pulp weights were compared with those in normoxic controls.Contrary to expectation, spleen weights and amounts of red pulp were greater (in terms of experimental‐control differences) in the animals kept at 72 kPa, suggesting that at 52 kPa loss of overall fitness reduced the adaptive erythropoietic response. However, in view of the fact that increased erythropoiesis has disadvantages as well as advantages, the lesser response at the lower pressure may not be wholly disadvantageous.Coefficients of variation of the spleen variables examined showed a tendency to decrease in the animals at 72 kPa, but rose markedly at 52 kPa. This finding was interpreted as indicating that at 72 kPa spleen and red pulp changes are adaptive, but at 52 kPa they indicate an overall relative failure of adaptive mechanisms, with consequent reduced somatic fitnes

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04242.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYImmersion refractometry is based on matching the refractive index of the medium to that of the cytoplasm of the cell, in which case the latter will have minimum contrast in the phase contrast microscope and will practically disappear. The cytoplasm is then said to be at the match point with the medium. Since the refractive index of a solution is related to its concentration by the formulan ‐ no=αC, the values for the refractive indices can be expressed in terms of the concentration of solids (g/100 ml) which in fact has been done throughout this work. The properties of a suitable immersion medium, its preparation and interpretation of numerical results have been discussed. Refractometric measurements were carried out on fungal hyphae and spores. The solid concentration in hyphae varies according to their age, physiological state and function. In general the highest values are found at sites of physiological activity, such as growth and reproduction, and may range from 11% to 30% of solid concentration. The solid concentration of mature, resting spores was found to be in the range of 45–54%, with the exception of a powdery mildew spores in which the concentration of solids was 30–32%.The germination of spores is preceded by a fall in the concentration of solids, and subsequent swelling before the emergence of the germ tube. When the solid concentration in pregerminating spore has fallen to about 20–30%, metabolic activity can take place and germination c

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04243.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYMany of the difficulties of staining plastic embedded tissues for light and electron microscopy derive from physical exclusion of hydrophilic staining reagents by hydrophobic embedding media. Structures which stain most intensely with hydrophilic reagents usually contain less hydrophobic plastic than do non‐staining structures. Such incomplete infiltration is apparently caused by exclusion of viscous, hydrophobic monomers by physically dense and/or well hydrated tissue elements. In keeping with this, generalized staining of tissues embedded in hydrophobic media does occur when hydrophobic reagents are used. Staining of plastic‐free structures with single hydrophilic reagents or with sequences of such reagents, is, however, largely rate‐controlled.The surprising similarity of hydrophilic and hydrophobic plastic embedding media is discussed.Limits of this simple model are explored, with a consideration of the roles of fixative and of monomer‐tissue re

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04244.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe exocrine pancreas and the parotid salivary gland have been widely used as models for studying the synthesis, intracellular transport and discharge of exportable proteins. This article briefly reviews quantitative morphological (stereological) studies which have been made of these glands and assesses their contribution to our understanding of the secretory process. A general stereological profile of these glands is presented and the way in which their morphology changes during development is outlined. Detailed consideration is given to the granule population of the cells, particularly the way in which granules are formed and discharged as a result of secretory stimuli. The membrane content of secretory cells and membrane dynamics during the secretory cycle are also examined. Throughout, the emphasis is placed on the interpretation of stereological data rather than on the methods themselves.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04245.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYThis review surveys some of the current approaches to the characterization of microscopical images using commercially available image analysers. The role of image pre‐processing and segmentation is considered, together with the characterization of images by optical density, as well as size and shape.The newer analysers are capable of investigating relationships between grey‐levels in small areas of the image (‘texture‐analysis’); some of the descriptive approaches in this latter field are briefly

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04246.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYA model of lymphatic metastasis of cancer has been established by injecting tumour cells into the rat footpad and examining the draining popliteal lymph node. The node can probably destroy only a few tumour cells; thereafter metastasis is progressive and lethal. The tumour cells penetrate the lymphatic endothelium, in the footpad either by moving singly between intact endothelial cells, by destroying the endothelium, or by passing in clumps between the endothelial cells. Tumour cells may then be obtained from the lymph by cannulation of the lymphatic trunk. These experiments pose the question: is local lymphatic chemotherapy useful in treating lymphatic metastasis?

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04247.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYThe preparation of a comprehensive set of gelatin‐glycerol‐salt standards for quantitation of diffusible ions in ultrathin cryosectioned tissue is described. This set of standards serves two basic functions. The first is to calibrate the X‐ray analytical system so that peak‐to‐continuum ratios obtained from test specimens may be converted to elemental concentrations. The second is to provide a known set of elemental concentrations which can be used to check the performance of the preparative and analytical steps involved in thin section biological X‐ray microanalysis. The application of these standards and techniques for cryoultramicrotomy and analysis of myocardial tissue also i

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04248.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SUMMARYA simple light‐microscopic method for the examination of fine details on cell surfaces is described. When cell specimens on platinum‐coated glass or plastic surfaces are stained with3,3′‐diaminobenzidine tetrahydrochloride and hydrogen peroxide, fine cytoplasmic processes that cannot be detected using conventional staining techniques for the light microscope are revealed. It is suggested the new technique be applied instead of the scanning electron microscope when the limited resolution of the light microscope is suf

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1983.tb04249.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY