Ultrastructural Studies of the Femoral Tendon Cells in the Freshly Molted Cockroach Nymph

Author(s):  
Martin Hagopian ◽  
David Spiro

In our electron microscopic studies of the freshly molted cockroach, Leucophaea maderae, the tendon (epidermal) cells in the nymph's femur show some characteristic features which have hitherto not been described. Within an hour of ecdysis the majority of tendon cells are attached to the cuticle and adjacent tendon cells; others are joined to the cuticle on one side and fastened to muscle on the opposite side; and some are apparently migrating free in the hemolymph. The tendon cells, whether adjacent to the cuticle or within the hemolymph, display very large numbers of microtubules and also have regions which contain rough endoplasmic reticulum and secretion granules (Fig. 1). The microtubules are oriented parallel to the myofilaments in underlying muscle cells.

Author(s):  
T. G. Merrill ◽  
B. J. Payne ◽  
A. J. Tousimis

Rats given SK&F 14336-D (9-[3-Dimethylamino propyl]-2-chloroacridane), a tranquilizing drug, developed an increased number of vacuolated lymphocytes as observed by light microscopy. Vacuoles in peripheral blood of rats and humans apparently are rare and are not usually reported in differential counts. Transforming agents such as phytohemagglutinin and pokeweed mitogen induce similar vacuoles in in vitro cultures of lymphocytes. These vacuoles have also been reported in some of the lipid-storage diseases of humans such as amaurotic familial idiocy, familial neurovisceral lipidosis, lipomucopolysaccharidosis and sphingomyelinosis. Electron microscopic studies of Tay-Sachs' disease and of chloroquine treated swine have demonstrated large numbers of “membranous cytoplasmic granules” in the cytoplasm of neurons, in addition to lymphocytes. The present study was undertaken with the purpose of characterizing the membranous inclusions and developing an experimental animal model which may be used for the study of lipid storage diseases.


Author(s):  
F. G. Zaki

Addition of lithocholic acid (LCA), a naturally occurring bile acid in mammals, to a low protein diet fed to rats induced marked inflammatory reaction in the hepatic cells followed by hydropic degeneration and ductular cell proliferation. These changes were accompanied by dilatation and hyperplasia of the common bile duct and formation of “gallstones”. All these changes were reversible when LCA was withdrawn from the low protein diet except for the hardened gallstones which persisted.Electron microscopic studies revealed marked alterations in the hepatic cells. Early changes included disorganization, fragmentation of the rough endoplasmic reticulum and detachment of its ribosomes. Free ribosomes, either singly or arranged in small clusters were frequently seen in most of the hepatic cells. Vesiculation of the smooth endoplasmic reticulum was often encountered as early as one week after the administration of LCA (Fig. 1).


Author(s):  
Sant S. Sekhon

Although there have been numerous studies concerning the morphogenetic changes accompanying the maturation of insect sperm, only a few deal with the sperm differentiation in the dragonflies. In two recent electron microscopic studies Kessel, has comprehensively treated the erlationship of microtubules to the nucleus and mid-piece structures during spermiogenesis in the dragonfly. The purpose of this study is to follow the sequential nuclear and cytoplasmic changes which accompany the differentiation of spermatogonium into a mature sperm during spermatogenesis in the dragonfly (Aeschna sp.).The dragonfly spermatogonia are characterized by large round nuclei. Loosely organized chromatin is usually unevenly distributed within the spermatogonial nuclei. The scant cytoplasm surrounding the nucleus contains mitochondria, the Golgi apparatus, elements of endoplasmic reticulum and numerous ribosomes (Fig. 1).


1977 ◽  
Vol 25 (3) ◽  
pp. 163-174 ◽  
Author(s):  
R C Spaur ◽  
G C Moriarty

The technique for using the water-soluble embedding medium glycol methacrylate has been improved for ultrastructural studies by the simplification of the method of formation of prepolymers used in embedding the tissue, by the addition of a cross-linking agent so that sections are stable in the electron beam, and by improving the softness of the blocks by the addition of a plasticizing agent. The preservation of tissue morphology has been improved by complete dehydration in glycol methacrylate monomer prior to infiltration with the prepolymer. Preservations of tissue morphology is further enhanced by complete dehydration in ethanols and embedding in the improved glycol methacrylate medium.


1962 ◽  
Vol 13 (1) ◽  
pp. 127-146 ◽  
Author(s):  
G. Adolph Ackerman

Electron microscopic studies of the bursa of Fabricius during the 15th and 16th day of embryonic development in the chick have shown the following findings in the submicroscopic structure of the cellular elements of the lympho-epithelial follicles. In the medulla, basal endodermal epithelial cells undergo mitosis and differentiation into lymphoblasts. During this transformation, there is a reduction in the amount of rough endoplasmic reticulum, an increase in the number or ribosomes, and frequently an enlargement of the Golgi complex. As lymphoblasts differentiate into medium lymphocytes there is a loss of endoplasmic reticulum, a reduction in the number of ribosomes and in the size of the Golgi complex, as well as a decrease in the number and size of mitochondria and in the size of the cell and nucleus. Cytoplasmic processes of reticular-epithelial cells extend between proliferating lymphocytic cells. Desmosomes connect stellate reticular-epithelial and basal epithelial cells but are not present in lymphocytic cells. Nuclear blebbing and vesiculation are frequently observed in the various cell forms of the developing lympho-epithelial nodules. Although lymphocytes and lymphocytopoietic activities in the cortex are sparse during this stage of embryonic development of the bursa, transitional forms between mesenchymal cells and lymphoblasts have been encountered. In addition, lymphoblasts and/or undifferentiated epithelial cells occasionally may pass through the basement membrane from the medulla into the cortical region of the developing nodule. That lymphocytes in the bursa of Fabricius originate from both endodermal and mesodermal derivatives during embryonic development appears to be consistent with both light and electron microscopic observations.


1976 ◽  
Vol 33 (11) ◽  
pp. 2551-2559 ◽  
Author(s):  
David E. Hinton ◽  
Raymond T. Jones ◽  
Roger Lee Herman

Light and electron microscopic studies were performed on tissues of hatchery-reared rainbow trout (Salmo gairdneri) having a disease of currently unknown etiology with external symptoms of severe edema which causes increased mortality rate. Comparison with unaffected trout tissues revealed loss of cellularity in glomerular tufts with a replacement of mesangial cells by connective tissue. Ultrastructural studies showed the material to be collagen and established the diagnosis of glomerular mesangial fibrosis. The glomerular lesion was associated with alterations in lining epithelium of proximal tubules and extensive debris within tubule lumens. The findings are compared to glomerular lesions in mammalian and amphibian kidney.


1998 ◽  
Vol 4 (S2) ◽  
pp. 1142-1143
Author(s):  
Elizabeth A. Richardson ◽  
Michelle Momany

The filamentous fungus Aspergillus nidulans partitions its cells by laying down septa at regularly spaced intervals in response to nuclear division. Physiological and genetic studies of the temperature-sensitive sep mutants have been especially useful in dissecting the regulation of septation. Electron microscopic studies of the sep mutants should be equally useful in dissecting the structural intermediates of septation. In preparation for ultrastructural studies of the sep mutants, we have examined septa in wild-type A. nidulans fixed by freeze substitution.Dialysis membranes were placed on rich medium plates and inoculated with A. nidulans spore suspensions. After 12 hours at 30°C, the dialysis membranes with adhering fungal hyphae were cut into square pieces measuring approximately 5mm on each side. The pieces were plunged into liquid propane and processed according to the procedures of Hoch. Serial sections were cut using a diamond knife and post stained with uranyl acetate and lead citrate.


Author(s):  
Betty G. Uzman ◽  
Marjorie Kasac

Electron microscopic studies of human tumors have been correlated by phase microscopy of ∼1μ sections with conventional histopathology. In tumor nodules from patients with fibrosarcoma (Fig. 1), malignant histiocytosis, and Hodgkin's disease (Figs. 2, 3, 4); in leukemic cells infiltrating spleen and lymph node; and in one parotid secretory cell (case of acute myeloblastic leukemia) alterations of the granular endoplasmic reticulum have been observed. These structures (indicated by arrows) resemble moth-eaten membranous bodies continuous with the encircling (Figs. 1, 2) or contiguous (Figs. 3, 4) cisternal wall. As many as five such alveolate reticular regions have been observed in a single cell.


Author(s):  
Hiroshi Saito ◽  
Goro Asano ◽  
Kaoru Aihara ◽  
Katsunari Fukushi ◽  
Minoru Yoshida ◽  
...  

This short communication is dealt with the ultrastructural changes of the chief cells in insulin stimulus in chronic gastritic condition. The bio gastro-endoscopic biopsy was obtained and pepsin activity of the gastric juice was measured in respective cases. Regular insulin of 0.15U/kg was administrated intra-muscularly and in pre-administration of insulin, 10 minutes, 20 minutes and 30 minutes after administration, biopsied specimens were subjected for electron microscopic studies.In the pre-treated chief cells, extensive development of the cysternal structures of the granular endoplasmic reticulum in basal aspect of the cytoplasm and spherical or oval shaped, light homogeneous zymogen granules in supranuclear region and especially apical aspect of the cytoplasm were featured. Moreover, other type of the chief cells as the one characterized by their fragmented and saccular dilated granular endoplasmic reticulum in basal aspect of the cytoplasm, also exist.


1978 ◽  
Vol 148 (2) ◽  
pp. 466-477 ◽  
Author(s):  
I Kushner ◽  
G Feldmann

To determine the cell of origin of C-reactive protein (CRP) and to cast light on the mechanisms leading to the acute phase response, we used an immunoenzymatic technique to visualize this protein in livers from rabbits at intervals after intramuscular injection of turpentine. CRP was detected only in hepatocytes. 8 h after turpentine injection, CRP was demonstrated in occasional periportal hepatocytes. With time, larger numbers of positive cells were detected successively in perilobular, midlobular, and centrilobular areas. On electron microscopy, CRP was detected in rough endoplasmic reticulum (RER), smooth endoplasmic reticulum (SER), and Golgi apparatus (GA). When colchicine was administered to inhibit cellular secretion of CRP, intensity of reaction and number of CRP-containing hepatocytes were substantially greater than without colchicine, but the sequence of intralobular distribution was similar. At peak serum response 38 h after turpentine injection, CRP could be demonstrated in most hepatocytes. Electron microscopic studies showed accumulation of CRP on membranes and lumina of RER, SER, GA, and in cytoplasmic vacuoles. These findings indicate that CRP is produced by progressively increasing numbers of hepatocytes after inflammatory stimulus and suggest that a mediator, acting initially in portal zones, is responsible for recruitment of cells to CRP production.


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