Isolation, structure and composition of cyst wall of Schizopyrenus russelli.
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Amino Acids↗
Biomedical subjects
A C Shipstone
Publications and source records attributed to A C Shipstone.
The ultrastructure of Entamoeba histolytica.
The ultrastructure of the trophozoite of Entamoeba histolytica cultivated in vitro on artificial media is described from electron-microscope studies made by the authors and from other published accounts. The authors point out that the description does not present a complete picture of the trophozoite of this species of amoeba since no detailed studies of the dysenteric form in infected host organs have yet been made and that nothing is known about the ultrastructure of cysts and the process of cyst formation, maturation and germination.The cytoplasm is confined by a 3-layered cytoplasmic membrane and contains many different organelles: subpellicular dark bodies, ribosomes, helical aggregates of ribosomes, osmiophilic lipoid granules, short dark tubular bodies of unknown origin and function, food vacuoles and some very small vacuoles thought to be lysosomes. Neither mitochondria nor a Golgi apparatus could be found. In the nucleus, the chromatin material is accumulated around the periphery and the nucleolus is centrally situated. The nuclear envelope is a double-layered membrane with numerous pores. Some groups of button-like particles were seen within the nucleus and it is thought that they are probably symbiotic virus-like particles.Some comparisons are made with the ultrastructure of other amoebae, both parasitic and free-living, and some further lines of study are suggested.
Entamoeba histolytica↗
Ventricular surface of rabbit hippocampus: a scanning electron microscope study.
Portions of the ependyma were obtained from the hippocampus of adult rabbits and processed for scanning electron microscopy. The major part of the ependymal surface was covered with a dense layer of cilia, some of these cilia showed bulbous preterminal enlargements. Irregularly arranged pits of variable diameter were also seen. Pes hippocampi showed fewer cilia and deeper furrows than did the remainder of the hippocampus.
Animals↗
Effect of vasectomy on the ultrastructure of epididymal epithelium in rhesus monkey.
Ultrastructural changes in the epididymal epithelium and the fate of accumulating spermatozoa were examined in the vasectomized rhesus monkey (Macaca mulatta). Accumulation of spermatozoa resulted in an increase in the diameter of the tubule and its lumen. Ultrastructure of principal cells revealed that they continue to perform both secretory and absorptive functions after vasectomy. The rough endoplasmic reticulum, Golgi complex, and mitochondria were well developed in the principal cell. Bulging of the apical portion of principal cells and membrane-bound structures in the lumen suggests an increase in apocrine secretion. An increase in the number of vesicles, vacuoles, and multivesicular bodies in the principal cells indicates an increased absorptive activity. Increased absorptive function was also evident in the apical cells. Macrophages with sperm remnants were seen in the lumen, and occasionally in the connective tissue. The principal or only mechanism of sperm disposal after vasectomy appeared to be intraluminal endocytosis by macrophages.
Animals↗
Ultrastructure of the epididymal epithelium of rhesus monkey (Macaca mulatta).
The regional fine structure of the epithelium lining the epididymis of the rhesus monkey has been investigated. Tall, prismatic principal cells constituted the major part of the epithelium. Their basal plasma lemma showed presence of caveolae and the luminal surface was studded with stereocilis. Presence of numerous desmosomes and tight junctions between adjacent principal cells suggested the existence of blood epididymis barrier. Ultrastructural evidence is presented in support of high lysosomal turnover, absorptive and secretory functions in these cells. Apocrine secretion was evident only in the principal cells of initial segment. Of the two types of basal cell, dark and pale, the latter revealed presence of lipofuscin pigment suggesting their scavenger role in the epithelium.
Animals↗
Ultrastructural changes in the principal cells of epididymis of adult rhesus monkey (Macaca mulatta) after castration and androgen replacement therapy.
The epididymal epithelium from adult castrated and androgen supplemented, castrated rhesus monkeys was examined with transmission electron microscope. Ninety days after bilateral castration the tubular diameter of all the regions of the epididymis, viz. the initial segment, caput, corpus and cauda portions of epididymis was reduced and was accompanied by a drop in cell size. There was a marked decrease in the number and size of microvilli on the luminal surface. The invaginations of apical membrane into the cell cytoplasm became less prominent. There was a reduction in the amount of smooth and rough endoplasmic reticulum, and Golgi complex. Mitochondria accumulated in the apical cytoplasm. Several vacuoles often associated with lipofuscin pigment granules were common in the cytoplasm. These findings suggest a reduction in both the absorptive and secretory functions of the principal cells. Following androgen replacement therapy for 30 days in monkeys that were castrated 60 days earlier there was a recovery of structural features in the epithelium to near normal state.
Animals↗
Epididymal basal cells in rhesus monkey (Macaca mulatta): ultrastructural changes after castration and androgen replacement therapy.
The ultrastructure of epididymal basal cells in adult castrated and castrate-androgen supplemented rhesus monkey was studied. Due to reduction in the height of the epithelium, three months after castration their number appeared to have increased. In the initial segment dark basal cells occupied more area in the epithelium and their cytoplasm showed the presence of large vacuoles. Cells that resembled dark basal cell were found at all heights of the epithelium. In all the segments, dark basal cells developed pseudopod-like structures. Pale basal cell cytoplasm was filled with lipofuscin pigment granules. Androgen replacement therapy for 30 days prior to autopsy at 90 days did not bring about any significant changes in the ultrastructure of both the types of basal cell. However, the size of the dark basal cell appeared to have decreased. The possible role of basal cells in the disposal of products accumulated in the principal cells under normal and altered endocrine conditions in discussed.
Animals↗
Ultrastructural changes in rabbit testis and epididymis following vasectomy: a long term study.
The Ultrastructural changes in testis and epididymis were studied in rabbits following 18 months of bilateral vasectomy. No fine structural changes were observed in seminiferous tubules and all stages of spermatogenesis appeared normal in most of the sample studied. Intracellular spaces in the spermatogonia cytoplasm may denote ionic deficiency. Digestion of sperms to some extent in the lumen of seminiferous tubules was denoted by the presence of round membrane bound bodies which may be remnants of digested cytoplasmic organelles and sperm parts. Cells of the epididymal epithelium showed normal characteristics. Electron dense bodies (lysosomes) were more prevalent in the supranuclear region of principal cells suggesting increased resorption capacity of caput epididymis after vasectomy. Presence of large oval bodies in the lumen needs further investigation.
Animals↗
Ultrastructural study of epidermal Langherhans cells in leprosy.
ATPase staining and ultrastructural study of skin biopsies from six patients of leprosy (2TT, 4LL) and three normal subjects was carried out to study Langherhans Cells (LC). ATPase staining showed normal counts of LCs in tuberculoid patients, while significant reduction was observed in lepromatous cases. Electron microscopy revealed morphological changes in LL cases in the form of dense matrix and indistinct cristae of mitochondria; decreased number of lysosomes and rough endoplasmic reticulum; and numerous vacuoles in cytoplasm. TT cases showed normal morphology. Possible role of Langerhans Cells in pathogenesis of leprosy is discussed.
Humans↗