scholarly journals THE FORMATION OF THE PRIMARY ENVELOPE DURING OOCYTE DIFFERENTIATION IN TELEOSTS

1967 ◽  
Vol 35 (1) ◽  
pp. 193-212 ◽  
Author(s):  
Everett Anderson
Keyword(s):  
Electron Microscopy ◽  
Amorphous Material ◽  
Light And Electron Microscopy ◽  
Stage Iv ◽  
Stage I ◽  
Dense Layer ◽  
Granular Component ◽  
Hippocampus Erectus ◽  
Oocyte Differentiation

The differentiation of the primary envelope of oocytes of the seahorse (Hippocampus erectus) and the pipefish (Syngnathus fuscus) has been investigated by techniques of light- and electron microscopy. The developing oocytes have been divided into four stages according to size. Oogonia are designated as stage I; stages II and III are oocytes; stage IV represents mature eggs. The primary envelope which is produced by the oocyte is initially a tripartite structure; for convenience of description, the portions are referred to as zones 1, 2, and 3, respectively. Zone 1 first appears as a homogeneous substance at approximately the middle of the long axis of each microvillus. Zone 2 is immediately beneath zone 1 and consists of an extremely electron-opaque granular component. Zone 3 is subjacent to zone 2; it is the largest and most complex of the three. Zone 3 consists of an amorphous material organized in a reticular-like network. Staining procedures indicate that the envelope is composed of a glycoprotein. Just before the oocyte matures there is a structural alteration in zones 2 and 3. Zone 2 becomes a compact, dense layer and zone 3 becomes multilaminate. Subsequent to these changes, zone 1 degenerates. The classification of egg envelopes is discussed, and comparisons are made between the primary envelope of the teleosts investigated and the primary envelopes of other species.

Electron Microscopy of Carcinomas of the Lung

1974 ◽  
Vol 32 ◽  
pp. 16-17
Author(s):  
B. Mackay ◽  
M. Mandavia ◽  
J. M. Lukeman ◽  
C. F. Mountain
Keyword(s):  
Electron Microscopy ◽  
Poor Prognosis ◽  
Light And Electron Microscopy ◽  
Malignant Neoplasm ◽  
Therapeutic Modalities ◽  
The Poor ◽  
Diagnosis And Classification ◽  
Methods Of Treatment ◽  
Insight Into

Carcinoma of the lung is the most common malignant neoplasm in males and the incidence continues to rise. The inadequacy of current methods of treatment is reflected in the poor prognosis: only 5% of patients survive for more than five years following diagnosis.In order to assess the effectiveness of new therapeutic modalities, accurate pathologic diagnosis is essential, and it is recognized that a proportion of these tumors can not be accurately classified by light microscopy alone. We have now studied over one hundred lung carcinomas with correlated light and electron microscopy, and our findings indicate that electron microscopy can be an invaluable aid in the diagnosis and classification of the tumors. Study of the fine structure of the tumor cells can provide the basis for a more precise classification than is currently used in clinical studies, and additionally give insight into problems of histogenesis.

Morphology and occurrence of two epibiotic marine gomphonemoid diatoms in China

Nova Hedwigia ◽  
2020 ◽  
Vol 111 (3) ◽  
pp. 271-285
Author(s):  
Lang Li ◽  
Chang-Ping Chen ◽  
Jia-Wei Zhang ◽  
Jun-Rong Liang ◽  
Ya-Hui Gao
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
First Record ◽  
South Yellow Sea ◽  
Epiphytic Diatoms ◽  
Original Species ◽  
The South Yellow Sea ◽  
Basic Features ◽  
Species Descriptions

Gomphonemoid diatoms exist in both freshwater and marine environment, but marine gomphonemoid taxa are morphologically different from Gomphonema. Although the marine gomphonemoid group has been expanded with many new taxa in recent years, only the genus Gomphonemopsis was described from Chinese seas. The present study reports on species diversity and classification of marine epiphytic diatoms on seaweeds and epizoic diatoms on animals collected from several stations in the South Yellow Sea and East China Sea. Two marine gomphonemoid diatoms, Pseudogomphonema kamtschaticum and Gomphoseptatum aestuarii, were observed and identified by light and electron microscopy, representing the first record in China of these two species and genera. Our observations matched the basic features of original species descriptions. Except that we observed in P. kamtschaticum showed various areolae shapes (e. g., slit-like, "I"-like, "C"-like and circular), and ornamented macroareolae with small warts were observed in G. aestuarii. Both P. kamtschaticum and G. aestuarii were epiphytic on the seaweed Sargassum hor neri, and P. kamtschaticum was found as epizoic on an ophiuroid species of the Ophiura genus. Therefore, we have increased the records of and knowledge about marine gomphonemoid diatoms to three genera with four species in China, including Gomphonemopsis.

Fertilization in the white chiton, Stenosemus albus, with implications for its phylogenetic position

2008 ◽  
Vol 86 (9) ◽  
pp. 1024-1030 ◽  
Author(s):  
J. Buckland-Nicks ◽  
C. Schander
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Direct Access ◽  
Phylogenetic Position ◽  
Dense Layer ◽  
Egg Membrane ◽  
Key Characters

Gamete structure and fertilization biology of the white chiton, Stenosemus albus (L., 1767), were studied with light and electron microscopy. Sperm structure was found to be similar to other Chitonina, but acrosomes are homogeneous in this species, like those of Chaetopleura apiculata (Say in Conrad, 1834). The egg of S. albus is covered by long spines with hooked tips. The bases of spines are perforated along their perimeters by a series of pores that provide sperm with direct access to the vitelline layer. This feature appears to be plesiomorphic and characterizes also Chaetopleura but not most Chitonina, which have a continuous dense layer overlying the hull. Beneath the vitelline layer, the egg membrane is formed into a series of cups with raised edges elaborated into microvilli that coincide with the bases of hull spines. Free-spawned sperm of S. albus were able to find the egg and penetrate a pore in the hull within 20 s. Evidence presented here, and previously, indicates that S. albus shares a number of key characters in common with Callochitonidae, which is a basal family within Chitonida. Taken together, the evidence suggests that Stenosemus belongs to a basal taxon within Chitonina, outside the Ischnochitoninae, in which it is currently placed.

The Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

Ultrastructure of mesotheliomas

1984 ◽  
Vol 42 ◽  
pp. 98-101
Author(s):  
Irving Dardick
Keyword(s):  
Electron Microscopy ◽  
Latent Period ◽  
Spindle Cell ◽  
Spindle Cell Sarcoma ◽  
Metastatic Adenocarcinoma ◽  
Cell Sarcoma ◽  
Cytological Features ◽  
Industrial Use ◽  
Degree Of Differentiation

With the extensive industrial use of asbestos in this century and the long latent period (20-50 years) between exposure and tumor presentation, the incidence of malignant mesothelioma is now increasing. Thus, surgical pathologists are more frequently faced with the dilemma of differentiating mesothelioma from metastatic adenocarcinoma and spindle-cell sarcoma involving serosal surfaces. Electron microscopy is amodality useful in clarifying this problem.In utilizing ultrastructural features in the diagnosis of mesothelioma, it is essential to appreciate that the classification of this tumor reflects a variety of morphologic forms of differing biologic behavior (Table 1). Furthermore, with the variable histology and degree of differentiation in mesotheliomas it might be expected that the ultrastructure of such tumors also reflects a range of cytological features. Such is the case.

Control of Autogenous Vein Grafts Prior to Reimplantation, By Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 106-107
Author(s):  
John H. L. Watson ◽  
John L. Swedo ◽  
M. Vrandecic
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Physiological Saline ◽  
Experimental Conditions ◽  
Vein Grafts ◽  
Arterial Blood ◽  
Saphenous Veins ◽  
Autogenous Vein ◽  
Control Of Parameters ◽  
Post Implantation

The ambient temperature and the nature of the storage fluids may well have significant effects upon the post-implantation behavior of venus autografts. A first step in the investigation of such effects is reported here. Experimental conditions have been set which approximate actual operating room procedures. Saphenous veins from dogs have been used as models in the experiments. After removal from the dogs the veins were kept for two hours under four different experimental conditions, viz at either 4°C or 23°C in either physiological saline or whole canine arterial blood. At the end of the two hours they were prepared for light and electron microscopy. Since no obvious changes or damage could be seen in the veins by light microscopy, even with the advantage of tissue specific stains, it was essential that the control of parameters for successful grafts be set by electron microscopy.

Ultrastructure of two neoplasms in culture compared with original biopsies

1984 ◽  
Vol 42 ◽  
pp. 50-51
Author(s):  
Joseph M. Harb ◽  
James T. Casper ◽  
Vlcki Piaskowski
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Biopsy Specimen ◽  
Cultured Cells ◽  
Light And Electron Microscopy ◽  
Human Tumor ◽  
Soft Agar ◽  
Human Tumor Cells ◽  
Morphological Distinction ◽  
Tumor Types

The application of tissue culture and the newer methodologies of direct cloning and colony formation of human tumor cells in soft agar hold promise as valuable modalities for a variety of diagnostic studies, which include morphological distinction between tumor types by electron microscopy (EM). We present here two cases in which cells in culture expressed distinct morphological features not apparent in the original biopsy specimen. Evaluation of the original biopsies by light and electron microscopy indicated both neoplasms to be undifferentiated sarcomas. Colonies of cells propagated in soft agar displayed features of rhabdomyoblasts in one case, and cultured cells of the second biopsy expressed features of Ewing's sarcoma.

The Effect of Vitamin A on the Intermittent Nitrogen Dioxide Gas Exposure in Hamsters

1976 ◽  
Vol 34 ◽  
pp. 176-177
Author(s):  
J.C.S. Kim ◽  
M.G. Jourden ◽  
E.S. Carlisle
Keyword(s):  
Electron Microscopy ◽  
Vitamin A ◽  
Nitrogen Dioxide ◽  
Chronic Exposure ◽  
Light And Electron Microscopy ◽  
Specific Effect ◽  
Deficient Diet ◽  
Intermittent Exposure ◽  
Hypovitaminosis A ◽  
Gas Exposure

Chronic exposure to nitrogen dioxide in rodents has shown that injury reaches a maximum after 24 hours, and a reparative adaptive phase follows (1). Damage occurring in the terminal bronchioles and proximal portions of the alveolar ducts in rats has been extensively studied by both light and electron microscopy (1).The present study was undertaken to compare the response of lung tissue to intermittent exposure to 10 ppm of nitrogen dioxide gas for 4 hours per week, while the hamsters were on a vitamin A deficient diet. Ultrastructural observations made from lung tissues obtained from non-gas exposed, hypovitaminosis A animals and gas exposed animals fed a regular commercially prepared diet have been compared to elucidate the specific effect of vitamin A on nitrogen dioxide gas exposure. The interaction occurring between vitamin A and nitrogen dioxide gas has not previously been investigated.

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