摘要:

SUMMARYInner shell ionization edges in the energy‐loss spectrum were used to measure the loss of gaseous elements from thin samples of nitrocellulose, polyvinyl formal, copper phthalocyanine, graphite bisulphate and sodium chloride during exposure to 80 keV electrons. The irradiation kinetics were measured for electron doses up to 104C m−2and for dose rates up to 10 mA m−2. The energy‐loss technique is discussed in relation to other methods for assessing radiation

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00288.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe usefulness of spray‐freezing for determining the sizes of sonicated vesicles of egg lecithin with various cholesterol concentrations has been demonstrated. It is found that vesicles of egg lecithin increase in average size with increasing cholesterol concentrations, in agreement with measurements obtained with other technique

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00289.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe necessity of low temperature preparative procedures for diffusible ion localization using the ion microscope has been established with rat liver as the test material. Using conventional fixation procedures, significant ion loss and redistribution were observed which exceeded the 1 μm lateral resolution of the direct imaging ion microanalyser. The compositional morphology evidenced in chemically prepared versus fast‐frozen, freeze‐dried, unfixed material was compared and evaluated in terms of ion retention, ion redistribution and morphological integrity. A mass spectral analysis of both preparations has been presented and discussed with regard to spectral interferences and elemental sensitivities. Ion images of sodium and potassium were recorded for chemically prepared liver sections and compared with the ion distributions obtained for unfixed, fast‐frozen, freeze‐dried 1 μm thick sections. The magnitude of ion loss during preparation of samples removed at different stages in the course of chemical processing was determined by atomic absorption and flame emission spectrop

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00290.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYWhen determining the number of nuclei (therefore cells) present in a known volume of tissue it is necessary to determine the overall mean caliper diameter of nuclei for each cell type studied. Most previous methods for determining the mean caliper diameters (D̄) of cell nuclei were strongly dependent upon assumptions of the shape of the particles in question (Greeleyet al., 1978). A computer program has now been designed to calculate D̄ from three‐dimensional reconstructions of nuclei in a manner that is independent of all shape assumptions. The D̄s of ten capillary endothelial cell nuclei from normal rat lungs have been determined by this shape‐independent method. The resulting overall mean caliper diameter for this group of ten nuclei varied only slightly from that previously estimated for them by a method which assumes them to be triaxial ellipsoids. In a similar comparison, the D̄s for ten normal human lung endothelial cell nuclei were determined by both methods. The overall mean caliper diameter determined by the shape‐independent method was 10% larger than that estimated by the shape‐dependent method. This suggests that human lung endothelial nuclei vary significantly from the shape assumption (triaxial ellipsoid) employed in the shape‐dependent method, and the shape‐independent method was considered to yield a more accurate m

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00291.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYAn exact method of preparation of soft biological specimens for electron microscopic analysis of surface fine structures is described. It allows routine preparations of fragile specimens for SEM and TEM imaging modes. With this procedure physical preparation parameters such as mechanical loads on the specimen surface or changes of temperature are controlled. The wet specimens are premounted in cheap disposable BEEM‐containers or glass boats and are constantly kept under liquid in a closed system. The exchange of preparation media is performed continuously and, if necessary, over gradients. For comparative investigations with different EM‐modes, at each step of the procedure parts of the specimens may be removed for individual processing. Conventionally prepared critical‐point dried specimens are compared to those processed by the exchange technique and preservation of surface fine structures is demonstrated. Shadow‐casted clathrin cages and stereo‐replicas of virus infected cell cultures are shown in TEM preparations. For SEM, coverslip cell cultures and isolated glomerulus basement membranes are prepared and an additional flat embedding for TEM ultrathin sections is dem

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00292.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThis examination represents the first scanning electron microscopic study of a proteocephalid tapeworm,Proteocephalus ambloplitis, and it also serves as the first comparative study between the adult and larval stages of a tapeworm.Proteocephalus ambloplitishas numerous microtrichs whose densities and diameters differ greatly from those of cyclophyllidean and pseudophyllidean tapeworms previously examined.Proteocephalus ambloplitisalso has an external apical organ and a subcuticular organ.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00293.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYMany histochemical procedures, in an attempt to be as variable‐free as possible, often require such a quantity of incubation solution that there is a resulting waste of expensive chemical substrates, coupling salts, antigens, etc. More economic procedures are justifiably ignored in histochemical studies because of their uncontrollable variables. However, the variables associated with one such economic procedure (the drop method) can now be eliminated by utilizing the closed‐chambered incubator described in this paper. Slides containing tissue sections incubated in this apparatus need only 1 ml of incubation medium per slide to achieve a similar reaction product as tissue sections emersed in Coplin jars of medium. This incubator incorporates a water‐bath circulator to heat and circulate water below a shelf containing the tissue sections. Within 0·5 h, the entire incubating chamber is saturated with a 310 K water vapour. The water vapour eliminates the primary variable of the drop method incubation, evaporation of the medium. This paper describes the construction of the incubator, its evaluation, the savings obtained from one simple histochemical procedure and its applicability in enzyme and the immunoperoxidase histochemical tech

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00294.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA procedure for electron microscope autoradiography of red blood cell ghosts or their outer membrane leaflets is described: sheep erythrocytes, attached to positively charged mica, were either lysed and air‐dried, or freeze‐fractured ‘by hand’ and freeze‐dried. This was followed by shadowing and carbon replication; coating with photographic emulsion; exposure in darkness at 277 K; developing and fixation; carbon coating; floating off the mica and mounting on grids. Erythrocytes iodinated with125I using the lactoperoxidase reaction were used as a test object. The efficiency of the procedure was found to be between 3·4

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00295.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYAn easily constructed heating stage has been designed for a Cambridge Scientific Instruments' Stereoscan Scanning Electron Microscope. This heating stage is capable of reaching temperatures of at least 1273 K. The stage is a simple design which can easily be built from non‐magnetic stainless steel and a natural stone consisting mainly of pyrophyllite. All heat shielding is made from these materials without the need for any liquid coolant surrounding the stage. The use of this heating stage as an instrument for the study of morphological changes during heating processes up to 1273 K is described briefl

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00296.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYPhosphorus‐containing standards for use during quantitative electron probe X‐ray microanalysis of ultrathin tissue sections can be quickly and simply prepared using organo‐phosphorus compounds which are soluble in Spurr's epoxy resin mixture. Trials of five such compounds (one solid, the rest liquid) are desc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb00297.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY