Scanning electron microscopy of plasma etched implant specimens

Following surface etching of previously processed plastic embedded specimens containing hard and soft tissues and implanted biomaterials with oxygen plasma, the fine structure of the tissues can be examined by scanning electron microscopy. One micrometer plastic orientation sections (with the implant removed in processing) and 110 microns histological sections (with the implant in situ) were examined. Direct comparison can be made between the scanning and histological observations. An examination in situ of oral tissues next to the biomaterial was also made, care being taken to minimize damage to the specimen. The fine structure of intracellular organelles was examined in detail. The method allows consecutive gathering of histological and ultrastructural data from the same plastic embedded specimen.     

Scanning electron microscopy of Penicillium conidia

The morphology of conidia in 211 species and 12 varieties belonging to the genus Penicillium Link ex Gray have been studied and compared.According to surface ornamentation, conidia have been classified into six groups: A, smooth-walled (7% of the species); B, delicately roughened (13%); C, warty (28%); D, echinate (10%); E, striate with low irregular ridges (36%); and F, striate with scarce high ridges or bars (6%). Whereas the first two groups are closely related in both shape and average size, a gradual reduction was observed in size and in the length/width (l/w) ratio in the remaining groups. Echinate conidia were globose, having the largest average size. Only four species produced conidia not surpassing 2 m in diameter. Maximum length observed was 8 m, and most elongated conidia had a l/w ratio of 3.5. Forty per cent of the species studied had globose conidia.Conidia of the monoverticillate species were generally smaller, more globose and frequently with ridges. In the Asymmetrica, the conidia were generally larger, and showed ridges in comparatively few species. Conidia of the Symmetrica, which were frequently striate with ridges, presented the most elongated forms. The largest average size was found in the conidia of the Polyverticillata which were generally warty. Finally, we have considered the variations in surface ornamentation of conidia during the evolution of the genus Penicillium and drawn attention to their possible relationship with certain habitats and ways of conidial dispersion.     

Scanning electron microscopy of barley protoplasts

Summary Scanning electron micrographs of barley protoplasts were compared using various preparatory techniques. Numerous features were observed which turned out to be artifactual characteristics of the processing procedure used in collecting and dehydrating the samples. The most successful technique gave protoplasts which presumably maintained their natural structural integrity, as judged by retention of sphericity and absence of holes in the plasma membrane. The relative numbers of fragmented protoplasts and cellular organelles was also greatly reduced.     

Scanning electron microscopy of vaginal colonization

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.     

Scanning electron microscopy of experimental adiaspiromycosis

Adiaspiromycotic granulomas of mice experimentally inoculated with fungusEmmonsia crescens Emmons et Jellison 1960 were examined by scanning electron microscopy. Their morphology, surface structures, and germinating adiaspores isolated from granulomas are described.     

Scanning electron microscopy of the chick embryo

Internal anatomical features of developing chick embryos can be examined using the scanning electron microscope in embryos that have been sectioned at varying levels. Standard paraffin sectioning techniques are used. After removal of paraffin, embryos are dried by the critical point method and examined. The resulting scanning electron micrographs have proved to be exceptionally useful in teaching anatomy of embryos.     

Scanning electron microscopy of primary membrane bone

Summary The organization and the development of primary bone were studied in a number of newborn or foetal mammals. Specimens were derived from long bones, calvaria and mandibles. The surface of the mineral component was exposed by treatment with an organic solvent (hot 1,2 ethane diamine or cold sodium hypochlorite solution) and in the case of some internal surfaces (endosteal surfaces of long bone shafts, endocranial aspects of calvaria and the lining of the dental groove or crypts of mandibles) some success was achieved in dissecting the soft tissues from the bone matrix surface. These surface were studied by scanning electron microscopy. Ground sections of similar material were studied by microradiography.Primary membrane bone was found to be most different from adult lamellar bone on rapidly growing (periosteal) surfaces and in the following respects. 1) Mineralization of both the ground substance and collagen occured close to the mineralizing front, so that a higher level was reached rapidly and without a maturation phase. 2) The mineral clusters at the mineralizing front did not reflect the collagen fibre distribution. 3) The collagen fibre bundles at the matrix surface, at least at internal surfaces, were irregular in size and random in orientation.Mineralizing fronts intermediate in character between those of rapidly forming, periosteal primary bone and adult lamellar bone were found on the uncommon internal forming surfaces and in the walls of vascular channels.Most internal surfaces were resorbing. There was a wide range in the size of the resorption lacunae — the many which were only as large as the osteocyte lacunae exposed by the resorption process may have been caused by uninucleated cells.This work has been supported by a grant from the Medical Research Council. The Stereoscan scannning electron microscope was provided by the Science Research Council, and the microradiographic equipment by Mr. R. V. Ely and the Ely-Webster trust. We would like to thank Mr. P. S. Reynolds, Miss A. J. Sutton and Mr. P. F. Farmer for technical and photographic assistance and Mrs. Jeanne Mills for secretarial assistance.     

Scanning electron microscopy of vaginal colonization.

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.