scholarly journals Shedding Light on the Dark Side of the Microglia

ASN NEURO ◽  
2020 ◽  
Vol 12 ◽  
pp. 175909142092533 ◽  
Author(s):  
Marie-Kim St-Pierre ◽  
Eva Šimončičová ◽  
Eszter Bögi ◽  
Marie-Ève Tremblay
Keyword(s):  
Current Knowledge ◽  
Postmortem Brain ◽  
Dark Side ◽  
Ultrastructural Changes ◽  
Molecular Profile ◽  
Homogeneous Population ◽  
Transmission Electron ◽  
Schizophrenic Patients ◽  
The Central Nervous System ◽  
Multiple Species

Microglia, the resident immune cells of the central nervous system, are not a homogeneous population; their morphology, molecular profile, and even their ultrastructure greatly vary from one cell to another. Recent advances in the field of neuroimmunology have helped to demystify the enigma that currently surrounds microglial heterogeneity. Indeed, numerous microglial subtypes have been discovered such as the disease-associated microglia, neurodegenerative phenotype, and Cd11c-positive developmental population. Another subtype is the dark microglia (DM), a population defined by its ultrastructural changes associated with cellular stress. Since their first characterization using transmission electron microscopy, they have been identified in numerous disease conditions, from mouse models of Alzheimer’s disease, schizophrenia, fractalkine signaling deficiency to chronic stress, just to name a few. A recent study also identified the presence of cells with a similar ultrastructure to the DM in postmortem brain samples from schizophrenic patients, underlining the importance of understanding the function of these cells. In this minireview, we aim to summarize the current knowledge on the DM, from their initial ultrastructural characterization to their documentation in various pathological contexts across multiple species. We will also highlight the current limitations surrounding the study of these cells and the future that awaits the DM.

scholarly journals MeHg Causes Ultrastructural Changes in Mitochondria and Autophagy in the Spinal Cord Cells of Chicken Embryo

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Fabiana F. Ferreira ◽  
Evelise M. Nazari ◽  
Yara M. R. Müller
Keyword(s):  
Spinal Cord ◽  
Mitochondrial Dynamics ◽  
Ultrastructural Changes ◽  
In Ovo ◽  
Cytoplasmic Inclusions ◽  
Autophagic Vacuoles ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Mantle Layer ◽  
The Central Nervous System

Methylmercury (MeHg) is a known neurodevelopmental toxicant, which causes changes in various structures of the central nervous system (CNS). However, ultrastructural studies of its effects on the developing CNS are still scarce. Here, we investigated the effect of MeHg on the ultrastructure of the cells in spinal cord layers. Chicken embryos at E3 were treated in ovo with 0.1 μg MeHg/50 μL saline solution and analyzed at E10. Then, we used transmission electron microscopy (TEM) to identify possible damage caused by MeHg to the structures and organelles of the spinal cord cells. After MeHg treatment, we observed, in the spinal cord mantle layer, a significant number of altered mitochondria with external membrane disruptions, crest disorganization, swelling in the mitochondrial matrix, and vacuole formation between the internal and external mitochondrial membranes. We also observed dilations in the Golgi complex and endoplasmic reticulum cisterns and the appearance of myelin-like cytoplasmic inclusions. We observed no difference in the total mitochondria number between the control and MeHg-treated groups. However, the MeHg-treated embryos showed an increased number of altered mitochondria and a decreased number of mitochondrial fusion profiles. Additionally, unusual mitochondrial shapes were found in MeHg-treated embryos as well as autophagic vacuoles similar to mitophagic profiles. In addition, we observed autophagic vacuoles with amorphous, homogeneous, and electron-dense contents, similar to the autophagy. Our results showed, for the first time, the neurotoxic effect of MeHg on the ultrastructure of the developing spinal cord. Using TEM we demonstrate that changes in the endomembrane system, mitochondrial damage, disturbance in mitochondrial dynamics, and increase in mitophagy were caused by MeHg exposure.

Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

1982 ◽  
Vol 40 ◽  
pp. 204-204
Author(s):  
D. M. DePace
Keyword(s):  
Blood Vessels ◽  
Superior Cervical Ganglion ◽  
Peripheral Nerves ◽  
Time Schedule ◽  
Transmission Electron ◽  
Cervical Ganglion ◽  
The Central Nervous System ◽  
Cervical Ganglia ◽  
Capillary Circulation ◽  
And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

Ultrastructural changes in murine lymphoma cells exposed to ultraviolet-A radiation

1991 ◽  
Vol 49 ◽  
pp. 104-105
Author(s):  
Delma P. Thomas ◽  
Dianne E. Godar
Keyword(s):  
Medical Devices ◽  
Blood Cells ◽  
White Blood Cells ◽  
Consumer Products ◽  
Ultrastructural Changes ◽  
Ultraviolet A ◽  
Uv Spectrum ◽  
Lymphoma Cells ◽  
Murine Lymphoma ◽  
Transmission Electron

Ultraviolet radiation (UVR) from all three waveband regions of the UV spectrum, UVA (320-400 nm), UVB (290-320 nm), and UVC (200-290 nm), can be emitted by some medical devices and consumer products. Sunlamps can expose the blood to a considerable amount of UVR, particularly UVA and/or UVB. The percent transmission of each waveband through the epidermis to the dermis, which contains blood, increases in the order of increasing wavelength: UVC (10%) < UVB (20%) < UVA (30%). To investigate the effects of UVR on white blood cells, we chose transmission electron microscopy to examine the ultrastructure changes in L5178Y-R murine lymphoma cells.

Morphologic alteration in the muscles of patients with hypokalemic periodic paralysis or myopathy

1990 ◽  
Vol 48 (3) ◽  
pp. 222-223
Author(s):  
T. Shimizu ◽  
Y. Muranaka ◽  
I. Ohta ◽  
N. Honda
Keyword(s):  
Clinical Manifestations ◽  
Quadriceps Muscle ◽  
Honeycomb Structure ◽  
Periodic Paralysis ◽  
Ultrastructural Changes ◽  
Hypokalemic Periodic Paralysis ◽  
Electron Microscopic ◽  
Tubular Aggregates ◽  
Hypokalemic Myopathy ◽  
Transmission Electron

There have been many reports on ultrastructural alterations in muscles of hypokalemic periodic paralysis (hpp) and hypokalemic myopathy(hm). It is stressed in those reports that tubular structures such as tubular aggregates are usually to be found in hpp as a characteristic feature, but not in hm. We analyzed the histological differences between hpp and hm, comparing their clinical manifestations and morphologic changes in muscles. Materials analyzed were biopsied muscles from 18 patients which showed muscular symptoms due to hypokalemia. The muscle specimens were obtained by means of biopsy from quadriceps muscle and fixed with 2% glutaraldehyde (pH 7.4) and analyzed by ordinary method and modified Golgimethod. The ultrathin section were examined in JEOL 200CX transmission electron microscopy.Electron microscopic examinations disclosed dilated t-system and terminal cistern of sarcoplasmic reticulum (SR)(Fig 1), and an unique structure like “sixad” was occasionally observed in some specimens (Fig 2). Tubular aggregates (Fig 3) and honeycomb structure (Fig 4) were also common characteristic structures in all cases. These ultrastructural changes were common in both the hypokalemic periodic paralysis and the hypokalemic myopathy, regardless of the time of biopsy or the duration of hypokalemia suffered.

Hepatocyte ultrastructural alterations in perimetastatic areas

1996 ◽  
Vol 54 ◽  
pp. 768-769
Author(s):  
H. J. Finol ◽  
M. E. Correa ◽  
L.A. Sosa ◽  
A. Márquez ◽  
N.L. Díaz
Keyword(s):  
Malignant Tumor ◽  
Malignant Tumors ◽  
Surrounding Tissue ◽  
Ultrastructural Changes ◽  
Pancreas Carcinoma ◽  
Duct Carcinoma ◽  
Tissue Samples ◽  
Primary Malignant Tumor ◽  
Transmission Electron ◽  
Remote Sites

In classical oncological literature two mechanisms for tissue aggression in patients with cancer have been described. The first is the progressive invasion, infiltration and destruction of tissues surrounding primary malignant tumor or their metastases; the other includes alterations produced in remote sites that are not directly affected by any focus of disease, the so called paraneoplastic phenomenon. The non-invaded tissue which surrounds a primary malignant tumor or its metastases has been usually considered a normal tissue . In this work we describe the ultrastructural changes observed in hepatocytes located next to metastases from diverse malignant tumors.Hepatic biopsies were obtained surgically in patients with different malignant tumors which metatastized in liver. Biopsies included tumor mass, the zone of macroscopic contact between the tumor and the surrounding tissue, and the tissue adjacent to the tumor but outside the macroscopic area of infiltration. The patients (n = 5), 36–75 years old, presented different tumors including rhabdomyosarcoma, leiomyosarcoma, pancreas carcinoma, biliar duct carcinoma and colon carcinoma. Tissue samples were processed with routine techniques for transmission electron microscopy and observed in a Hitachi H-500 electron microscope.

scholarly journals Plant Species of Sub-Family Valerianaceae—A Review on Its Effect on the Central Nervous System

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 846
Author(s):  
Gitishree Das ◽  
Han-Seung Shin ◽  
Rosa Tundis ◽  
Sandra Gonçalves ◽  
Ourlad Alzeus G. Tantengco ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Plant Species ◽  
Current Knowledge ◽  
Biological Properties ◽  
In Vivo Studies ◽  
Food Species ◽  
The Central Nervous System ◽  
Preclinical And Clinical Studies

Valerianaceae, the sub-family of Caprifoliaceae, contains more than 300 species of annual and perennial herbs, worldwide distributed. Several species are used for their biological properties while some are used as food. Species from the genus Valeriana have been used for their antispasmodic, relaxing, and sedative properties, which have been mainly attributed to the presence of valepotriates, borneol derivatives, and isovalerenic acid. Among this genus, the most common and employed species is Valerianaofficinalis. Although valerian has been traditionally used as a mild sedative, research results are still controversial regarding the role of the different active compounds, the herbal preparations, and the dosage used. The present review is designed to summarize and critically describe the current knowledge on the different plant species belonging to Valerianaceae, their phytochemicals, their uses in the treatment of different diseases with particular emphasis on the effects on the central nervous system. The available information on this sub-family was collected from scientific databases up until year 2020. The following electronic databases were used: PubMed, Scopus, Sci Finder, Web of Science, Science Direct, NCBI, and Google Scholar. The search terms used for this review included Valerianaceae, Valeriana, Centranthus, Fedia, Patrinia, Nardostachys, Plectritis, and Valerianella, phytochemical composition, in vivo studies, Central Nervous System, neuroprotective, antidepressant, antinociceptive, anxiolytic, anxiety, preclinical and clinical studies.

Pulmonary Endothelial Cell Modifications after Storage in Solid-Organ Preservation Solutions

1995 ◽  
Vol 23 (3) ◽  
pp. 200-206 ◽  
Author(s):  
P Carbognani ◽  
L Spaggiari ◽  
M Rusca ◽  
L Cattelani ◽  
P Solli ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Organ Preservation ◽  
Ultrastructural Changes ◽  
Osmic Acid ◽  
Solid Organ ◽  
Ringer Lactate ◽  
University Of Wisconsin ◽  
Transmission Electron ◽  
Grading Scale

During lung preservation, the vascular endothelium is probably the first site of damage and these lesions are considered the main limiting factor in solid-organ preservation. In the present study, the ultrastructural changes in the endothelial cells of human pulmonary artery hypothermically stored (at 4 °C) for 6 and 12 h in Euro-Collins, University of Wisconsin and Ringer-lactate solutions were compared. The arteries obtained from three patients who underwent pneumonectomy were divided into 20 segments and preserved in the three solutions mentioned. The specimens, which were fixed in osmic acid, were examined using transmission electron microscopy. Transmission electron microscopy indicated that the cells stored in the University of Wisconsin solution either for 6 or 12 h were the best preserved, while the most severely damaged cells were those stored in Euro-Collins solution, even after just 6 h. The cells stored in Ringer-lactate showed an intermediate level of damage. The data from an ultrastructural grading scale, which quantified the damage to the cytoplasm, mitochondria and nucleus, were in broad agreement with the general transmission electron microscopy observations. Analysis of variance of the grading scale data showed that there were statistically significant differences between the groups after both 6 and 12 h storage ( P < 0.05).

scholarly journals Pollen, Tapetum, and Orbicule Development inColletia paradoxaandDiscaria americana(Rhamnaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Gotelli ◽  
B. Galati ◽  
D. Medan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
The Family ◽  
Tapetal Cells ◽  
Grain Formation

Tapetum, orbicule, and pollen grain ontogeny inColletia paradoxaandDiscaria americanawere studied with transmission electron microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells and related to orbicule and pollen grain formation are described. The proorbicules have the appearance of lipid globule, and their formation is related to the endoplasmic reticulum of rough type (ERr). This is the first report on the presence of orbicules in the family Rhamnaceae. Pollen grains are shed at the bicellular stage.

scholarly journals Lipid Transport and Metabolism at the Blood-Brain Interface: Implications in Health and Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Fabien Pifferi ◽  
Benoit Laurent ◽  
Mélanie Plourde
Keyword(s):  
Fatty Acids ◽  
Neurodegenerative Diseases ◽  
Current Knowledge ◽  
Lipid Transport ◽  
Omega 3 ◽  
Blood Brain ◽  
Brain Interface ◽  
The Central Nervous System ◽  
Health And Disease ◽  
The Brain

Many prospective studies have shown that a diet enriched in omega-3 polyunsaturated fatty acids (n-3 PUFAs) can improve cognitive function during normal aging and prevent the development of neurocognitive diseases. However, researchers have not elucidated how n-3 PUFAs are transferred from the blood to the brain or how they relate to cognitive scores. Transport into and out of the central nervous system depends on two main sets of barriers: the blood-brain barrier (BBB) between peripheral blood and brain tissue and the blood-cerebrospinal fluid (CSF) barrier (BCSFB) between the blood and the CSF. In this review, the current knowledge of how lipids cross these barriers to reach the CNS is presented and discussed. Implications of these processes in health and disease, particularly during aging and neurodegenerative diseases, are also addressed. An assessment provided here is that the current knowledge of how lipids cross these barriers in humans is limited, which hence potentially restrains our capacity to intervene in and prevent neurodegenerative diseases.

scholarly journals Latency- and Defense-Related Ultrastructural Characteristics of Apple Fruit Tissues Infected with Botryosphaeria dothidea

2001 ◽  
Vol 91 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Ki Woo Kim ◽  
Eun Woo Park ◽  
Young Ho Kim ◽  
Kyung-Ku Ahn ◽  
Pan Gi Kim ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fungal Growth ◽  
Apple Fruit ◽  
White Rot ◽  
Ultrastructural Changes ◽  
Disease Development ◽  
Botryosphaeria Dothidea ◽  
Transmission Electron ◽  
Thin Electron ◽  
Apple Fruits

Apple fruit tissues infected with Botryosphaeria dothidea were examined by transmission electron microscopy using susceptible cv. Fuji and resistant cv. Jonathan. Immature (green) and mature (red) fruits of cv. Fuji with restricted or expanding lesions were also examined to reveal subcellular characteristics related with latent and restricted disease development. In infected susceptible mature fruits, cytoplasmic degeneration and organelle disruption commonly occurred, accompanying cell wall dissolution around invading hyphae. Cell wall dissolution around invading hyphae in subepidermis was rare in immature, red halo-symptomed cv. Fuji and resistant cv. Jonathan fruits. In infected immature fruits of cv. Fuji, presumably at the latent state of disease development, cellular degeneration was less severe, and invading hyphae contained prominent microbody-lipid globule complexes or the deposition of thin electron-dense outer layer around cell wall of intercellular hyphae. Both mature fruits with red halos and resistant apple fruits formed cell wall protuberances at the outside of cell walls. In addition, electron-dense extramural layers were formed in the resistant apple fruits. Aberrant hyphal structures such as intrahyphal hyphae were found only in resistant fruit tissues, indicating the physiologically altered fungal growth. These ultrastructural changes of host tissues and fungal hyphae may reflect the pathogenesis of apple white rot under varying conditions of apple fruits.

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