The Role of Mitochondria in the Genesis of Neuroaxonal Dystrophy in the Brains of Aging Mice

Author(s):  
J.E. Johnson

Although neuroaxonal dystrophy (NAD) has been examined by light and electron microscopy for years, the nature of the components in the dystrophic axons is not well understood. The present report examines nucleus gracilis and cuneatus (the dorsal column nuclei) in the brain stem of aging mice.Mice (C57BL/6J) were sacrificed by aldehyde perfusion at ages ranging from 3 months to 23 months. Several brain areas and parts of other organs were processed for electron microscopy.At 3 months of age, very little evidence of NAD can be discerned by light microscopy. At the EM level, a few axons are found to contain dystrophic material. By 23 months of age, the entire nucleus gracilis is filled with dystrophic axons. Much less NAD is seen in nucleus cuneatus by comparison. The most recurrent pattern of NAD is an enlarged profile, in the center of which is a mass of reticulated material (reticulated portion; or RP).

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 579
Author(s):  
Fei Yang ◽  
Lingli Yang ◽  
Lanting Teng ◽  
Huimin Zhang ◽  
Ichiro Katayama

The role of Langerhans cells (LCs) in vitiligo pathogenesis remains unclear, with published studies reporting contradictory results regarding the quantity of LCs and no data on the features of LCs in vitiligo. Here, we aimed to analyze the presence, density, and morphological features of LCs in the epidermis of patients with vitiligo. Skin biopsies were stained for LCs using anti-CD1a/anti-langerin antibodies and analyzed by immunocytochemistry with light and electron microscopy. Compared with healthy controls, we detected significantly increased numbers of epidermal LCs in lesional skin from vitiligo in the progressive state. These LCs exhibited striking morphological alterations, including an elevated number of dendrites, with increased length and more branches than dendrites from controls. Ultrastructure examination via immuno-electron microscopy revealed markedly reduced Birbeck granules (BGs) and shorter BG rods in LCs from progressive vitiligo, with higher expression of langerin. Additionally, expression of S100B, the activity biomarker of vitiligo, was increased in these LCs. This work provides new insight on the cellular composition of LCs in vitiliginous skin, revealing altered morphology and increased LC numbers, with elevated S100B expression. Our data suggest LCs might play a critical role in vitiligo pathogenesis and thus may represent a novel therapeutic target for this disease.


PEDIATRICS ◽  
1984 ◽  
Vol 73 (2) ◽  
pp. 218-224
Author(s):  
S. Rousset ◽  
O. Moscovici ◽  
P. Lebon ◽  
J. P. Barbet ◽  
P. Helardot ◽  
...  

Since the outbreaks of neonatal necrotizing enterocolitis occurring in maternity hospitals of Paris and suburbs in 1979-1980, it has been possible to examine by light and electron microscopy gut specimens from ten newborns with this illness. Coronavirus-like particles, enclosed in intracytoplasmic vesicles of damaged epithelial cells of the intestinal mucosa, were observed in the small intestine, appendix, and colon. The ultrastructural study, supported by bacteriologic findings, suggests the role of coronavirus-like particles in the appearance of the lesions. Secondary proliferation of mainly anaerobic bacteria, probably responsible for pneumatosis, may aggravate the disease.


2008 ◽  
Vol 7 (3) ◽  
pp. 509-517 ◽  
Author(s):  
Jacob Lorenzo-Morales ◽  
Jarmila Kliescikova ◽  
Enrique Martinez-Carretero ◽  
Luis Miguel De Pablos ◽  
Bronislava Profotova ◽  
...  

ABSTRACT Acanthamoeba infections are difficult to treat due to often late diagnosis and the lack of effective and specific therapeutic agents. The most important reason for unsuccessful therapy seems to be the existence of a double-wall cyst stage that is highly resistant to the available treatments, causing reinfections. The major components of the Acanthamoeba cyst wall are acid-resistant proteins and cellulose. The latter has been reported to be the major component of the inner cyst wall. It has been demonstrated previously that glycogen is the main source of free glucose for the synthesis of cellulose in Acanthamoeba, partly as glycogen levels fall during the encystment process. In other lower eukaryotes (e.g., Dictyostelium discoideum), glycogen phosphorylase has been reported to be the main tool used for glycogen breakdown in order to maintain the free glucose levels during the encystment process. Therefore, it was hypothesized that the regulation of the key processes involved in the Acanthamoeba encystment may be similar to the previously reported regulation mechanisms in other lower eukaryotes. The catalytic domain of the glycogen phosphorylase was silenced using RNA interference methods, and the effect of this phenomenon was assessed by light and electron microscopy analyses, calcofluor staining, expression zymogram assays, and Northern and Western blot analyses of both small interfering RNA-treated and control cells. The present report establishes the role of glycogen phosphorylase during the encystment process of Acanthamoeba. Moreover, the obtained results demonstrate that the enzyme is required for cyst wall assembly, mainly for the formation of the cell wall inner layer.


2004 ◽  
Vol 14 (02) ◽  
pp. 453-491 ◽  
Author(s):  
EROL BAŞAR ◽  
MURAT ÖZGÖREN ◽  
SIREL KARAKAŞ ◽  
CANAN BAŞAR-EROĞLU

The present report describes the dynamic foundations of long-standing experimental work in the field of oscillatory dynamics in the human and animal brain. It aims to show the role of multiple oscillations in the integrative brain function, memory, and complex perception by a recently introduced conceptional framework: the super-synergy in the whole brain. Results of recent experiments related to the percept of the grandmother-face support our concept of super-synergy in the whole brain in order to explain manifestation of Gestalts and Memory-Stages. This report may also provide new research avenues in macrodynamics of the brain.


BIOspektrum ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 161-164
Author(s):  
Till Stephan ◽  
Peter Ilgen ◽  
Stefan Jakobs

AbstractMitochondria are essential cellular organelles, which supply eukaryotic cells with the universal energy carrier adenosine triphosphate. These organelles feature a unique double-membrane architecture, which is formed by a smooth outer membrane and a highly folded inner membrane. Harnessing super-resolution light and electron microscopy, we investigate the role of MICOS, a large mitochondrial protein complex, in determining the complex folding of the inner membrane.


Blood ◽  
1964 ◽  
Vol 23 (3) ◽  
pp. 300-320 ◽  
Author(s):  
ROBERT J. CAPONE ◽  
EVA LURIE WEINREB ◽  
GEORGE B. CHAPMAN

Abstract The development of representative myeloid elements is traced by correlated light and electron microscopy. Cytoplasmic changes during maturation of granulocytes from the myeloblast include loss of basophilia, development of the endoplasmic reticulum complex, decrease in number of mitochondria, and granule formation. The endoplasmic reticulum vesicles increase in size and number during the promyelocyte and myelocyte stages, accompanied by the appearance of non-specific and specific granules, and decrease again during the cytosomal maturation of the metamyelocyte. A reduction in number of mitochondria is noted through the metamyelocyte stage. The apparent continuity of the limiting membranes of both the granules and mitochondria with those of the cisternae of endoplasmic reticulum suggests a direct connection among cytosomal organelles. The role of the endoplasmic reticulum in granulogenesis is discussed. Maturation of the nucleus involves a loss of nucleolar differentiation by a loosening of the compact fibrillar aggregates, and progressive chromatin condensation.


1988 ◽  
Vol 25 (2) ◽  
pp. 131-137 ◽  
Author(s):  
E. Momotani ◽  
D. L. Whipple ◽  
A. B. Thiermann ◽  
N. F. Cheville

Ligated ileal loops of calves were inoculated with live and heat-killed Mycobacterium paratuberculosis and were examined by light and electron microscopy. At 5 hours after inoculation, acid-fast bacilli were in subepithelial macrophages, but not in M cells covering domes. At 20 hours, more than 50 acid-fast bacilli per cross section were in subepithelial macrophages in domes. Both living and heat-killed bacilli passed into domes. Addition of anti- M. paratuberculosis bovine scrum to the inoculum enhanced entry of bacteria into domes. By electron microscopy, intact bacilli with electron-transparent zones (peribacillary spaces) were in the supranuclear cytoplasm of M cells at 20 hours. M cells also contained vacuoles, including electron-dense material interpreted as degraded bacilli. Subepithelial and intraepithelial macrophages contained bacilli and degraded bacterial material in phagosomes. These results suggest that calf ileal M cells take up bacilli, and that subepithelial and intraepithelial macrophages secondarily accept bacilli or bacterial debris which are expelled from M cells.


2018 ◽  
Vol 14 (2) ◽  
pp. 381-387 ◽  
Author(s):  
İbrahim Unal Sert ◽  
Ozcan Kilic ◽  
Murat Akand ◽  
Lutfi Saglik ◽  
Mustafa Cihat Avunduk ◽  
...  

2013 ◽  
pp. 35-45 ◽  
Author(s):  
H.-Y. LU ◽  
L.-Z. CHEN ◽  
X.-Y. JIANG ◽  
Y. MO ◽  
Y.-H. LING ◽  
...  

We used a rat model to assess the role of nephrin, podocin, and desmin in the pathogenesis of IgA nephropathy (IgAN). A rat IgAN model was established by administration of BSA, CCl4, and lipopolysaccharide (LPS) and compared with healthy control rats. Urinary protein, urine red blood cells, and biochemical parameters were measured for 12 weeks. Renal morphology and ultrastructure were examined by light and electron microscopy. Immunofluorescence was used to assess IgA deposition in the glomeruli and to measure expression of nephrin, podocin, and desmin. Real-time quantitative PCR was used to measure expression of nephrin, podocin, and desmin mRNAs. IgAN rats developed proteinuria at week-6 and this worsened over time. Pathological changes were evident under light microscopy at week-8 and under electron microscopy at week-4. Immunofluorescence analysis showed deposition of IgA in the kidneys of IgAN rats, but not control rats. IgAN rats had increased expression of glomerular podocin, nephrin, and desmin mRNAs and proteins at week-4. The expression of nephrin, podocin and desmin proteins and the expression of podocin and desmin mRNAs preceded the increase in urinary protein. Taken together, our study of a rat model of IgAN indicates that changes in the expression and distribution of nephrin, podocin, and desmin precede and may cause foot process fusion and proteinuria.


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