Biological significance of recombination-activating gene 1, RAG1 in optic nerve neuropathy

Development of oligodendrocytes in rat corpus callosum was described as a sequential change in cytoplasmic density which progressed from light to medium to dark (1). In rat optic nerve, changes in cytoplasmic density were not observed, but significant changes in morphology occurred just prior to and during myelination (2). In our study, the ultrastructural development of oligodendrocytes was studied in newborn, 5-, 10-, 15-, 20-day and adult frontal cortex of the golden hamster (Mesocricetus auratus).Young and adult hamster brains were perfused with paraformaldehyde-glutaraldehyde in sodium cacodylate buffer at pH 7.3 according to the method of Peters (3). Tissue samples of layer V of the frontal cortex were post-fixed in 2% osmium tetroxide, dehydrated in acetone and embedded in Epon-Araldite resin.

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Microstructural morphology of sphingolipid dispersions as investigated by freeze-fracture EM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141093 ◽

1995 ◽

Vol 53 ◽

pp. 944-945

Author(s):

Vitthal S. Kulkarni ◽

Wayne H. Anderson ◽

Rhoderick E. Brown

Keyword(s):

Acyl Chain ◽

Biological Significance ◽

Freeze Fracture ◽

Fatty Acyl ◽

Fatty Acyl Moiety ◽

Aqueous Dispersions ◽

Head Groups ◽

Lipid Species ◽

Microstructural Morphology ◽

Layer Chromatography

The biological significance of the sphingomyelins (SM) and monoglycosylated sphingolipids like galactosylceramides (GalCer) are well documented Our recent investigation showed tubular bilayers in the aqueous dispersions of N-nervonoyl GalCer [N-(24:lΔ15,cls) GalCer] (a major fatty acyl moiety of natural GalCer). To determine the influence of lipid head groups on the resulting mesophasic morphology, we investigated microstructural self-assemblies of N-nervonoyl-SM [N-(24:1 Δ15,cls) SM; the second most abundant sphingomyelin in mammalian cell membranes], 1- palmitoyl-2-nervonoyl phosphatidylcholine [PNPC] (the lipid species with the same acyl chain configuration as in N-(24: 1) GalCer) and also compared it with egg-SM by freeze-fracture EM.Procedures for synthesizing and purifying N-(24:1) GalCer, N-(24:1) SM, and PNPC have been reported . Egg-SM was purchased from Avanti Polar Lipids, Alabaster AL. All lipids were >99% pure as checked by thin layer chromatography. Lipid dispersions were prepared by hydrating dry lipid with phosphate buffer (pH 6.6) at 80-90°C (3-5 min), vigorously vortexing (1 min) and repeating this procedure for three times prior to three freeze-thaw cycles.

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Ultrastructural Localization Study of Carcinoembryonic Antigen (CEA) in Gastric Cancer: Immunoelectron Microscopic Observation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158807 ◽

1990 ◽

Vol 48 (3) ◽

pp. 252-253

Author(s):

Dong Yuming ◽

Yang Guanglin ◽

Wu Jifeng ◽

Chen Xiaolin

Keyword(s):

Gastric Cancer ◽

Intestinal Metaplasia ◽

Cancer Cells ◽

Microscopic Observation ◽

Biological Significance ◽

Ultrastructural Localization ◽

Mucinous Carcinoma ◽

Surface Glycoprotein ◽

Tubular Adenocarcinoma ◽

Pap Method

On the basis of light microscopic observation, the ultrastructural localization of CEA in gastric cancer was studied by immunoelectron microscopic technique. The distribution of CEA in gastric cancer and its biological significance and the mechanism of abnormal distribution of CEA were further discussed.Among 104 surgically resected specimens of gastric cancer with PAP method at light microscopic level, the incidence of CEA(+) was 85.58%. All of mucinous carcinoma exhibited CEA(+). In tubular adenocarcinoma the incidence of CEA(+) showed a tendency to rising with the increase of degree of differentiation. In normal epithelia and intestinal metaplasia CEA was faintly present and was found only in the luminal surface. The CEA staining patterns in cancer cells were of three types--- cytoplasmic, membranous and weak reactive type. The ultrastructural localization of CEA in 14 cases of gastric cancer was studied by immunoelectron microscopic technique.There was a little or no CEA in the microvilli of normal epithelia. In intestinal metaplasia CEA was found on the microvilli of absorptive cells and among the mucus particles of goblet cells. In gastric cancer CEA was also distributed on the lateral and basal surface or even over the entire surface of cancer cells and lost their polarity completely. Many studies had proved that the alterations in surface glycoprotein were characteristic changes of tumor cells. The antigenic determinant of CEA was glycoprotein, so the alterations of tumor-associated surface glycoprotein opened up a new way for the diagnosis of tumors.

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