Scanning electron microscopic studies of the rat incisor odontoblastema

Summary A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts.Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at -70° C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron microscopic levels.This study was supported by the Swedish Medical Research Council and the Faculty of Odontology, University of Göteborg, Göteborg, Sweden.     

Scanning electron microscopic studies of the vasa vasorum of thoracic aortas

Using hot alkaline solution, the elastic laminae were extracted from aortas and observed with scanning electron microscopy. Vascular structures were found in the elastin layers of the tunica media in descending thoracic aortas of sheep, dogs, and pigs, and these tube-like structures were filled with elastomer which was injected through the heart of the animal in vivo. Sub-intimal microvessels were also found to be filled with the elastomer and it is concluded that vasa vasorum can exist close to the internal elastic lamina in these animals.     

Scanning electron microscopic studies of Paracoccidioides brasiliensis in the yeast phase

Scanning electron microscopy of four different Paracoccidioides brasiliensis isolates in the yeast phase revealed that mother cells generating multiple, spherically shaped buds may be firmly or tenuously associated with their progeny whereas elongated buds remain attached to the mother cell through stem-like structures and may represent early stages of hypha formation. The yeast cell surfaces were covered with a delicate network of microfibrillar components.     

Scanning electron microscopic studies on the development of the chick retina

Fixed retinae of chick embryos and chicks of the first week after hatching were fractured and examined with the scanning electron microscope. The matrix cells of the retina proliferate up to the beginning of the second week. The migrating cells are oriented in cell cords. This columnar organization prevails up to the development of the plexiform layers formed as a consequence of the outgrowth of the dendritic and axonal cell processes.Special attention was paid to the differentiation of the ganglion, bipolar and receptor cells, and the radial fibers (Müller cells).     

Scanning electron microscopic studies on the synaptic bodies in the rat retina

Summary The ultrastructure of the synaptic bodies in the outer and inner plexiform layers of the rat retina was studied with scanning and transmission electron microscopy.The synaptic bodies in the outer plexiform layer are pear-shaped and their vitreal pole invaginated by processes from nerve cells. Their surfaces are covered with extracellular material, which is partly dissolved or redistributed during the fixation and rinsing procedure. The internal structure of the synaptic bodies is described.The synaptic bodies in the inner retinal plexiform layer are more difficult to identify with the scanning electron microscope. They are polyhedronal and also covered with extracellular material.The observations are discussed. The value of the application of two different preparation and analyzing methods, i. e. the scanning and the transmission electron microscopy, is stressed.Supported by grants from the Swedish Medical Research Council (B70-12X-2543-02), Expressens prenatalforskningsfond and Riksföreningen mot Cancer (265-B69-01X).     

Scanning electron microscopic analysis of breast aspirates

Scanning electron microscopic analysis (SEM) of 50 pre-selected breast aspirates was performed after light microscopy and cytomorphological evaluation. SEM analysis of these aspirates revealed the presence of microvilli (mv), microprojections, blebs and irregular contours in malignant cells. Benign cells were regular, globular and smooth. SEM provided additional morphologic data which if used in conjunction with light microscopy can assist in reaching a correct diagnosis.     

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 studies of Centaurea L. s.s. pollen

Abstract

The purpose of this study is to analyse, by means of Scanning Electron Microscopy (SEM), the validity of the typification of the pollen of Centaurea L. s.s., carried out by Wagenitz (1955) with light microscopy and based on the exine structure and sculpturing. The pollen of six species have been analyzed: one species for every type of pollen present in Italy: C. sempervirens L., C. alpina L., C. scabiosa L., C. alba L., C. montana L., C. cyanus L.

The validity of the pollen typification suggested by Wagenitz has been confirmed also at the ultramicroscopic level. The ultrastructure and the sculturing of the sporoderm are described in detail and some discrepancies, mainly due to the different potentialities offered by the two methods, are pointed out.     

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 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 studies of Trypanosoma cruzi in the rectum of its vector Triatoma infestans

The cuticular surface of the rectum of Triatoma infestans and its colonization by a Trypanosoma cruzi strain originating from the same locality as the bugs were studied by scanning electron microscopy at different weeks post infectionem. On the basis of the cuticular folding, the rectum can be subdivided into five regions. The rectal gland has the finest structure and the region anterior to the anus the deepest folds. Try. cruzi always prefers to colonize the rectal gland, while the other regions are colonized in varying densities. Most of the flagellates are epimastigotes (long and short), except in the region at the entrance of the midgut, where trypomastigotes predominate.     

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 observations of Thelazia callipaeda from human

Four females and a male nematode isolated from 2 patients who visited eye clinics in Seoul were identified as Thelazia callipaeda and their ultrastructures were observed by scanning electron microscopy (SEM). General features of the worms were slender and attenuated at both ends. Vaginal opening was located at 0.27 mm from the anterior end, and in front of the esophago-intestinal junction. In the body cuticle transverse striations varied characteristically through the body. The number of cuticular transverse striations was 400-650/mm at head portion, 250/mm at middle portion and 300-350/mm at tail portion. The SEM observation of the mouth part of the females showed 6 cord-like cuticular thickenings in hexagonal arrangement and an amphid was observed. A lateral line, a vaginal opening, a pair of phasmids, and an anus were identified in the body portion. A pair of papillae and 6 cord-like cuticular thickenings were on the mouth part of the male. It was difficult to observe structures at the tail of the male except wrinkle-like structures. Most of the larvae isolated from the uterus of a female worm were sheathed and thus cuticular striations were not seen. Others were un-sheathed and revealed cuticular striations. The oval membrane which encysted sheathed larvae was also observed. These are the 18th and 19th record of human thelaziasis in Korea as the literature are concerned.     

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.