摘要:

SUMMARYPieces of integument containing cuticle and hypodermal cells from the desert locustSchistocerca gregariawere pulse‐labelled to produce very narrow bands of radioactive chitin or resilin in the cuticle. Araldite sections of such cuticle were used as a radioactive line source to test the resolution and the possible effect of self‐absorption due to heavy metal staining of tissue‐sections in EM autoradiographs.The approximate position of the source and the half‐distance of resolution (HD) in EM autoradiographs were determined by replotting the grain‐distribution in integrated form, producing a sigmoid‐shaped curve. The values of HD, the position of the source and the total number of grains were then used to superimpose a theoretical grain‐density distribution function on the experimental grain‐distribution histograms. The results confirm the line or very narrow band nature of the radioactive chitin or resilin in the tissue‐sections used.When the source was resilin situated in the cuticle at about 1 μm from the cell‐surface, the values for HD were 130–180 nm in Ilford L4 and about 100 nm in Agfa‐Gevaert NUC 307. When the source was chitin situated just outside the cell surface, the corresponding value for HD in Ilford L4 was 85–125 nm. Possible adverse effects of electron beam damage on resolution in resilin‐containing samples are discussed.In sections with radioactive chitin at the cell surface, the total number of grains in the cell‐side of the histogram was always significantly lower than that in the cuticle‐side. This marked asymmetry in grain distribution is considered to be indicative of much greater self absorption of beta‐particles from the tritium source, in hea

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03848.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYSectioning of charcoal is extremely difficult since the knife usually shatters the section into minute fragments. In order to prevent such shattering it is necessary to both infiltrate the charcoal with a hard wax and to support the section during cutting with adhesive cellulose tape.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03849.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThis paper considers the relationship between the bulk matching of plane stacks abutting an interphase interface and the resultant matching of plane rings seen in the field‐ion image. An image contrast model is developed whereby the interfacial parameters may be deduced from field‐ion investigations and the methods of data acquisition and handling are conside

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03850.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThis paper demonstrates the use of the analytical techniques, developed in the companion paper, to determine interfacial parameters from a variety of multiphase structures. It is shown that accurate orientation relationships and the structure of unknown phases can be derived from this approach. In some cases assumptions have to be made concerning some of the interfacial parameters, but these assumptions can always be checked from the self‐consistency of the full analysi

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03851.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYA combination of enzymes have been employed to remove certain components of the adult bovine ligament sequentially. The course of this sequential enzymic dissection has been followed by scanning electron microscopy. We have been able to define the organization of elastic fibres embedded in matrix of collagen fibrils. The elastic fibres themselves appear to be made up from an amorphous core of elastin surrounded by a knitted sheath; the latter probably contains a mixture of collagen together with an unidentified protein component.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03852.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe xylem transfer cells of the wheat node have been examined in the scanning electron microscope following a preparative procedure of partial embedding in epoxy resin sufficient to prevent delicate structures from collapse during polymerization and scanning electron microscopy examination.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03853.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe maintenance and true pictorial representation of the complex cyto‐architecture of tissues is the aim of the preparatory methods for scanning electron microscopy. The procedure employed eliminates complications associated with and due to the vacuum technology necessarily employed in electron optic instruments using a scanning beam. Tissues are fixed by vascular perfusion after the administration of heparin eliminating clot formation. The infusion of Araldite in the tissues prevents the collapse and disorganization of cells due to the combined effects of dehydration, the vacuum of the scanning electron microscope and the scanning beam. The specimens are scoured with acetone and the blocks cured, this latter process ensures their permanence; the standard procedures of gold coating, stub mounting and painting the bases of specimens with a colloidal silver solution are then carried out. The method allows magnifications of the order of 10,000 diameters and an acceptable resolution of some 50 nm is obtained. Cytoarchitectural features demonstrated by the method described are borne out by transmission microscop

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03854.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYAmong the well established facts we can count that the cortex increases in volume against the thalamus as well as against the basal ganglia as we go from smaller to larger forms, and that the thickness of the cortex does not increase uniformly with the size of the brain. The details of the size of the thalamus and of the basal ganglia are not satisfactorily established. The values for the brains of whales and of man, which were measured by several individuals, but by the same technique, agree very well with each other.The number of cells in the cortex is not known with any degree of accuracy nor is the theoretical value of the grey cell coefficient well established. We advocate abandoning it, and replacing it with some measure of the number of synapses and/or the number of nerve fibres entering and leaving the cortex which can be established with greater accuracy.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03855.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe internal fine structure of extraocular muscle cells was observed with scanning electron microscopy. One micrometre Epon sections were etched with an iodine acetone solution. When adhered to carbon coated glass, such specimens may be viewed without surface coating. Such preparations provide information about the fibrillar organization of the muscle fibre, as well as its transverse tubular system and M line.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03856.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYMandibles, salivary glands, trachea, costal cartilages and kidneys of young adult, male, sibling rats were fixed in chilled, modified Lavdowsky's solution. The mandibles and blocks from the other tissues were then exposed to one of four demineralizers: Win 3000 and 20% formic acid, Greep's solution, 5% nitric acid and 10% EDTA. For comparison with demineralized tissues, a replicate set of tissues, other than mandibles, from each animal was processed without exposure to demineralizers.Paraffin sections of all tissues were stained with Alcian blue at pH 2–6 and at pH 0.5, with PAS and with Mowry's revised colloidal iron. The effect of the demineralizers on the staining intensities, tinctorial qualities, and cellular details were studied by pairwise comparison of each slide of a common tissue‐stain group with every other slide of the group. A comparison microscope was used and a numerically expressed preference ranking was obtained for each slide.Analysis of variance tests and Duncan's new multiple range tests were applied to determine the preferred demineralizers. Scoring results of the mandibles indicated that Win 3000 and 20% formic acid was either the preferred demineralizer or in each case not significantly different from the preferred one. Reliability of the findings was reduced because of inconsistencies among soft tissues not exposed to any deminerali

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03857.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY