Scanning electron microscopic study of uropathogen adherence to a plastic surface

We used a polyethylene surface to study the adherence of various urinary pathogens to a representative inert surface. The bacteria were suspended in filter-sterilized urine during this adhesion study, and differential adhesion was clearly demonstrated. Pseudomonas aeruginosa adhered most avidly and formed large microcolonies that were surrounded by an extensive amorphous matrix. Staphylococcus saprophyticus also formed microcolonies on the surface of the plastic droppers. In general, piliated strains of Escherichia coli adhered less avidly than the other organisms, but more avidly than nonpiliated strains; however, one piliated strain of E. coli adhered very poorly and behaved like a nonpiliated strain.     

Scanning electron microscopic study of hedgehog uteri

Ultrastructural studies of hedgehog uteri (Erinaceus europaeus L.) have been made using animals in anestrus, in estrus and in estrus after sojourn of a week with a male. In estrus and anestrus the uterine epithelium is homogeneous, regularly interrupted by orifices of glands. It is composed of microvillous cells only. Microvilli decrease in number and length in anestrus. A new type of cell, a ciliated cell, appears after copulation. Probable correlation of ultrastructural aspects of endometrium with hormonal situation is discussed.     

Scanning electron microscopic study of hyalin joint cartilage

Guinea pigs (pirbright white) were subjected to fixed mechanical stress in an endless-belt experiment. Shoulder, elbow, hip, and knee joints were taken and the articular cartilage was prepared for examination with the scanning electron microscope. Ultrastructural findings of cartilage surfaces were described, using different techniques for preparation and fixation. Mechanically stressed animals showed defects in their superficial 'chondrosynovial membrane' with visible fibre networks.     

Scanning electron microscopic study of vegetative mycelium of higherBasidiomycetes

The morphological character of vegetative mycelium was studied in eight species of higherBasidiomycetes by scanning electron microscopy. Morphology and variability of anastomoses, hyphal outgrowths, ornamentation and exudates, together with other irregularities in the form of hyphae are described and discussed from the point of view of their possible significance in the culture identification and taxonomic exploitation at the species level. Some of the morphological structures as observed in the scanning electron microscope are described here for the first time.     

Scanning electron microscopic study of clamp connections in higherBasidiomycetes

Clamp connections on vegetative hyphae of six species belonging to different groups of higherBasidiomycetes were studied by scanning electron microscopy. Different types of clamps, short and long, high and low, small and large, gently or abruptly curved, medallion-type and without a slit, single, coupled and in whorls, as well as clamps occurring on anastomoses were observed. No characteristic features usable for the species-specific differentiation of the vegetative mycelia of higherBasidiomycetes were found. Greater variability in the type of clamps, especially in their distribution on hyphae, found in species belonging toAphyllophorales contributes to the theory of their relative primitivism in comparison withAgaricales.     

Scanning electron microscopic study of natural killer cell-mediated cytotoxicity

The interaction between human natural killer (NK) cells and NK-susceptible target cells, as well as the mechanism involved in target cell lysis, were studied with scanning electron microscopy (SEM). Low density human peripheral blood lymphocytes, highly enriched with large granular lymphocytes (LGL), were used as effector cells, and K562-cells were used as NK-susceptible target cells. The surface features of LGL/NK cells were examined under SEM. In the area of interaction, NK/target-cell conjugates showed microvilli and/or filipodia, and extensive areas of intercellular contact. In addition, the effector cells in some NK/target-cell conjugates were polarized toward the target cell. Changes in target cell surface features included loss of microvilli, large surface blebs and the appearance of small pore-like lesions on the cell membrane. Our findings show that target cell lysis occurred by apoptosis and plasma membrane lesions analogous to those seen during complement-mediated cytotoxicity.     

Scanning electron microscopic study of spermatozoa from gossypol-treated rats

Summary Spermatozoa from the cauda epididymidis of gossypol-treated rats exhibit distinctive departures from the morphology of spermatozoa from control rats: wrinkled and disorganized cell membrane in the head and tail regions, cell membrane missing from segments of the tail midpiece and principal piece regions, malformed heads, decapitate spermatozoa, retention of a cytoplasmic droplet at variable loci along tail midpieces, and looped tails. The observations suggest that gossypol exerts its contraceptive effect during spermatocytogenesis and spermiogenesis, including the posttesticular development and maturation of spermatozoa in the epididymis.     

The cervical epithelial surface. III. Scanning electron microscopic study in atypias and invasive carcinoma in mice.

The anatomy of the epithelial surface of the uterine cervix was investigated in 31 mice with scanning electron microscope (SEM). The cervox of 20 mice was painted twice a week during five months with 3,4-benzpyrene (BP) in acetone and in 11 mice with acetone alone. Only two of the 15 acetone or BP treated animals with histologic normal epithelium showed similar structures as those described earlier for the normal cervical epithelium of untreated mice. The remaining 13 animals had regular mosaics, intermediate or cobblestone structures covered with irregular microvilli with or without long, finger-like protrusions. Irregular mosaics, intermediate or cobblestone structures were seen in atypical epithelium. In atypias Grade III and in invasive carcinoma irregular cobblestone structures with cellular overlapping were present. Atypical and invasive carcinoma were usually furnished with irregular microvilli, irregular fragmented microrugae and finger-like protrusions. The proportion of mice having anisovillosis with finger-like protrusions increased with increasing degree of epithelial severity. Since pathologic SEM changes were observed in some treated mice having normal histology the possibility was entertained that alterations at the cellular membrane level may preceed the nucleocytoplasmic changes required for the recognition of atypical epithelium in conventional histologic preparations.     

Scanning electron microscopic investigations of acute leukemia.

Twenty cases of acute lymphoblastic leukemia (ALL) in children and adults were investigated at different tissue localizations by scanning electron microscopy. ALL was divided into cases with or without strong paranuclear acid phosphatase activity. ALL showed very similar surface morphology irrespective of the type of ALL or the tissue localization. ALL is, however, strikingly different in some from other childhood leukemias and lymphomas, as well as from activated T-lymphocytes in infectious mononucleosis. The results indicate that the surface morphology of leukemic cells is a stable cytologic parameter, if certain technical prerequisits are fulfilled. Further criteria may thus be added to the panel of known cytologic, cytochemical and functional parameters.     

Scanning electron microscopic observations of polyacrylamide gels.

Structures of polyacrylamide gels have been viewed in a scanning electron microscope. Structures observed after freeze-drying of the gels have been substantiated by different experiments as the preexisting structure of the gels in their state of hydration. Parameters of content and polymerization of polyacrylamide gels have been varied to reveal their effects on the observed morphology. The structural patterns revealed by electron microscopy suggest a model of both the polymerization and the molecular-sieving properties of these gels.     

Scanning electron microscopic study of the effects of pressure on the luminal surface of the rabbit aorta.

The effects of pressure on the luminal surface of the rabbit aorta were investigated using the scanning electron microscope. The method followed was perfusion under hydrostatic pressure of a section of thoracic aorta, in vitro. The characteristic ridged pattern seen in sections fixed at zero hydrostatic pressure was to a large extent eliminated when fixation occurred at pressures equivalent to those experienced by the aorta at systole or diastole. This study suggests that the spiral ridged pattern is dependent upon the fixation pressure and may not be present in a normally functioning artery. Any attempts to characterize or interpret the appearance of the luminal arterial wall must take into account the effects of pressure.     

Scanning electron microscopic study of anamorphs of someBasidiomycetes in culture

The anamorphs in cultures ofLepista nuda (Bull.:Fr.)Cooke,Coprinus comatus (Müll.:Fr.)S.F. Gray,Fistulina hepatica Sohaeff.:Fr.,Pholiota adiposa (Fr.)Kumm. andAsterophora lycoperdoides (Bull.)S.F. Gray, an imperfect state ofNyctalis lycoperdoides (Bull.)Schroet., were studied by scanning electron microscopy. Arthroconidia were described inLepista nuda for the first time. Examination of the fine structure of dendroid forms inCoprinus comatus revealed why those structures were not propagative.     

The corpus luteum of the pig. Scanning electron microscopic study of surface features at different times of incubation

The surface ultrastructure of porcine early corpus luteum cells (days 1-3 of the luteal phase) was studied in SEM and correlated with progesterone secretion. Luteal cells were divided into 2 groups: small cells (10-20 microns) and large cells (20-30 microns) and their surface features were observed after 1, 3, and 5 h of incubation in the control medium and in a medium supplemented with prolactin (PRL). The surface morphology of control cells was characterized by numerous smooth blebs and the presence or absence of thin microvilli. Small and large cells showed a tendency to adhere to the glass during the experiment, but on the large cells the number of thin adhesive filopodia was greater. After the 1st and 3rd h of incubation with PRL the number of microvilli and numerous filopodia on the small cells increased substantially. Nodular blebs were scattered and appeared to protrude from the cell surface. Many small cells adhered to the glass by thick, layered and thin thread-like cytoplasmic processes. After the 5th h distinct smoothing of the surface of the small cells was seen. The number of microvilli seen on the PRL stimulated surface of the large cells was smaller and in some cases even entirely absent. After the 1st and 3rd h of the experiment the large cell surface was ruffled with minute folds. Numerous nodular blebs protruded from the cell surface. The number of adhesive filopodia attaching the cells to the glass decreased or vanished during the experiment. After the 5 h of incubation most of the cells had smooth surface with smooth blebs. Progesterone secretion was measured by radioimmunoassay. The cells in the medium without exogenous hormone (control) secreted relatively low levels of progesterone throughout 1-5 h of the incubation period. After addition of PRL to the medium the amount of secreted progesterone increased.     

Scanning electron microscopic study of human gallbladder mucosa in cholelithiasis

The mucosa of 17 gallbladders removed because of cholelithiasis was examined by means of transmission and scanning electron microscopy. Scanning electron micrographs revealed a mulberry-like organization of the normal human gallbladder mucosa. In acute inflammation, circumscribed ulcers were often seen; along their margins the epithelial cells were swollen and isolated from the surrounding cells. In chronic cholecystitis there was an extensive lack of epithelium on the irregularly oriented folds of the mucosa and the characteristic mulberry-like organization was preserved only in islets.     

Scanning electron microscopic studies of cilia

Summary A simple method for the preparation of ciliated epithelia for study with the scanning electron microscope is described. Ciliary groups are well preserved and it is possible to discern individual cilia and work out their numbers and orientation. Following scanning electron microscopical study some of the material was prepared for transmission electron microscopy and the ultrastructure of the tissue was found to be surprisingly well preserved. The tracheal epithelium of the rabbit, the olfactory epithelia of the goldfish and the rabbit, and the sensory epithelia in the statocyst of a cephalopod mollusc were examined with the scanning electron microscope to demonstrate the possibilities of the method. Acknowledgements. We would like to thank Professor J. Z. Young for his continued interest and support. The scanning electron microscope was purchased with a grant provided by the Science Research Council to Dr. Boyde, Mr. R. Willis helped in the initial stages of the study, Mr. G. Savage provided help with the goldfish material, Mr. S. Waterman provided much photographic assistance, and Mrs. N. Finney the secretarial assistance.     

Scanning electron microscopic surface analysis of cryoconserved skull bone after decompressive craniectomy

Bone flaps removed during decompressive craniectomy are commonly frozen at ?80 °C and stored until cranioplasty. Histological integrity and regenerative capacity have been shown for cryoconserved bone. The effects of cryoconservation on the surface structure are unknown, although these might cause mechanical instability or facilitate bacterial adhesion. This study evaluates the surface structure of cryoconserved bone by scanning electron microscopy. Five patients were identified who could not receive their autologous bone flaps after decompressive craniectomy. These redundant bone specimens were obtained after cryoconservation for 6–8 months and the outer surface was analyzed by scanning electron microscopy. We found varying surface structures which did not correlate with any variables, such as patient age, gender or duration of freezing, and probably reflect physiological interindividual variation. Pathological findings, such as microscopic crack formation, were not observed. Cryoconservation for up to 8 months does not appear to alter the surface structure of skull bone on scanning electronic microscopy.     

Reversion to bacillary forms of Serratia marcescens spheroplasts induced by carbenicillin. Scanning electron microscopic study

Bacterial cells of Serratia marcescens were easily induced to form spheroplasts in liquid medium by the addition of carbenicillin. The spheroplasts were unable to divide, but they were able to revert to the bacillary forms in liquid medium not containing carbenicillin. Four phases of the reversion sequence could be differentiated by scanning electron microscopy. (1) After 3 hr of incubation in carbenicillin-free medium, some projections arose out of the spheroplasts, and grew and elongated. (2) Their elongation resulted in a morphological change in the spheroplasts from spherical bodies to long irregular bacillary forms. (3) Further incubation caused several constricted areas in the bacillary form. (4) The long bacillary forms split along the constricted areas to become the parent bacillary forms of S. marcescens. When the long bacillary form that developed during the reversion was retreated with carbenicillin, it was immediately induced to become a spheroplast again.