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At least 757 records · Page 42Linked to original sources
PubMed1987

Congenital dyserythropoietic anaemia type II (HEMPAS): characterization of aberrant intracellular organelles by immunogold electron microscopy.

Erythrocytes are reticulocytes obtained from peripheral blood of a congenital dyserythropoietic anaemia type II patient were examined by immunoelectron microscopy using anti-band 3 and anti-glycophorin A antibodies. Vacuoles which have membranous structures inside were stained heavily by these antibodies, indicating the presence of band 3 and glycophorin A in these vacuoles. Empty vacuoles which open to the cell surface and those present in cytoplasm were also stained by these antibodies at the inside of the wall. These observations suggest that the vacuoles are functioning for trapping and discarding the defective plasma membranes. On the other hand, small vesicles and ferritin-loaded vacuoles were not stained by these antibodies. In these experiments, peripheral cisternae and most of the intracellular membranous structures at blebs and clefts were not stained by the antibodies. Therefore, they are probably part of the endoplasmic reticulum or are derived from intracellular organelles but not from the plasma membranes.

Anemia, Dyserythropoietic, Congenital↗
PubMed1987

Preparation of the mammalian organ of Corti for scanning electron microscopy.

The effect of various standard tissue preparation procedures for scanning microscopy on the morphology of the mammalian organ of Corti has been examined. Comparison was made of (i) different fixatives: glutaraldehyde (GA) alone, osmium (Os) alone, GA and Os together and GA followed by Os; (ii) freeze-drying (FD) versus critical point-drying (CPD); (iii) ligand binding of osmium with thiocarbohydrazide (TOTO procedure) versus sputter coating to provide a conductive coat. Results were assessed in terms of known structural parameters in fresh tissue. It is shown: (i) that double fixation, either GA, Os together or GA followed by Os, consistently produced less tissue distortion than either fixative alone, (ii) that FD produced less shrinkage of the tissue than CPD, and (iii) that the TOTO procedure appeared to rigidify the tissue and enhanced preservation of the morphology.

Animals↗
PubMed1988

Freeze-fracture of 3T3 cells for high-resolution scanning electron microscopy.

Triton-extracted, freeze-fractured 3T3 cells have been examined in the Hitachi S-900 field-emission SEM, after light platinum coating, at low beam voltage to evaluate the performance of the microscope under these conditions. For unstained material fixed in glutaraldehyde alone, high-resolution images can be obtained, at accelerating voltages of 1.5-5kV, after rotary deposition of platinum to an average thickness of 1.5-3 nm. Comparisons are made between these results and those of studies by TEM of deep-etch replicas of similar material previously published.

Cell Nucleus↗
PubMed1980

Scanning and transmission electron microscopy of material adherent to intrauterine contraceptive devices.

The material adherent to intrauterine contraceptive devices (IUCDs) has been studied by transmission and by scanning microscopy coupled with X-ray microprobe analysis. Inert (Lippes Loop D, Saf-T-Coil and Dalkon shield) and medicated (Copper 7 and Progestasert) IUCDs were removed for examination from uteri immediately after hysterectomy. The cellular material identified on the surface of all inert IUCDs consisted mainly of macrophages with some polymorphonuclear leucocytes, erythrocytes, a few platelets and fibrin fibres. Polymorphonuclear leucocytes were the principle cells on the copper devices. Larger numbers of cells were evident on the inert arms than on the active part of the Progestasert device. All the devices examined exhibited varying amounts of surface calcium deposition. The IUCDs which had been in utero for longer periods showed the greatest amount of calcium deposition. Although a less rapid calcium deposition appeared to occur on the Progestasert device, this deposition may influence the release of medications from IUCDs which are retained in utero for longer periods than one year.

Calcium↗
PubMed1987

Scanning electron microscopy of early microbial colonization of human enamel and root surfaces in vivo.

This study describes the pattern of microbial colonization in six dental students, who carried test pieces of enamel and root surface in intraoral acrylic appliances for 4, 8, 12, 24, and 48 h, respectively. Oral hygiene was discontinued during the experimental periods. The results showed that oral microorganisms colonized enamel and root surfaces individually. The pattern of colonization mimicked the surface structure of the tooth; on enamel surfaces the first bacteria appeared in pits and surface irregularities followed by proliferation along the perikymata, while on root surfaces bacterial colonization was characterized by a haphazard distribution. Within the initial 24-h period root surfaces were more heavily colonized than were enamel surfaces. This pattern was characteristic irrespective of differences in the intra- and interindividual rates of bacterial coverage. It is concluded that early microbial colonization in vivo is determined by the surface structure of the tooth. Consequently, natural tooth surfaces should not be replaced by artificial surfaces in structural studies of microbial deposits in the oral cavity.

Adult↗
PubMed1988

Transmission and scanning electron microscopy and freeze-fracture replication of normal human melanocytes and human melanoma cells in tissue culture.

Basic LM, TEM, SEM, and FFR appearances of a pure line of normal human melanocytes derived from foreskin, and a human melanoma line, in cell culture are described. Normal melanocyte cultures exhibit side by side, cells of widely different melanogenic activities--possible clones--and melanosomes of bizarre shape and internal structure are frequent. Aggregates of melanosomes, with or without associated amorphous material, and with no discernible limiting membrane are present within many cells, and occasional simple specialised contacts occur between apposed cells. On replicas of plasma membrane of normal melanocytes, particle densities and diameters on P and E fracture faces were within the ranges for cells in general, and equivalent data for the melanoma cells were not significantly different. Similarly, there was no difference in density of distribution or diameter of nuclear pores between the normal and the tumoural cells.

Cell Line↗