Ultrasonically Induced Changes in Synapses

1981 ◽  
Vol 39 ◽  
pp. 492-493
Author(s):  
M. J. Borrelli
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carotid Arteries ◽  
Functional Changes ◽  
Transmission Electron ◽  
The Common ◽  
Induced Changes ◽  
Common Carotid Arteries ◽  
The Brain ◽  
Tissue Ultrastructure

It had previously been demonstrated that controlled ultrasonic exposures of the mammalian central nervous system (CNS) produced reversible nerve potential suppression and irreversible limb paralysis. These functional effects appeared immediately after the exposures,but no abnormal morphology was detected with the light microscope for at least 10 min, and not all exposures resulting in functional changes produced observable altered morphology. It was therefore speculated that ultrasound produced its initial effects within the tissue ultrastructure,and that some post-exposure time was required before any changes attained dimensions observable with light microscopy.Ultrasonically exposed CNS tissue has recently been examined with transmission electron microscopy and induced changes have been observed within 30 sec after the exposure. Adult female cats were anesthetized and placed in a stereotaxic unit. The animals were prepared for ultrasonic exposure of the brain as described by W. Fry and the common carotid arteries were cannulated.

An ultrastructural study of reproduction in the parthenogenetic metacercariae of Cercaria margaritensis Ching, 1982 (Digenea: Gymnophallidae)

Parasitology ◽  
2003 ◽  
Vol 126 (3) ◽  
pp. 261-271 ◽  
Author(s):  
S. W. B. IRWIN ◽  
K. V. GALAKTIONOV ◽  
I. I. MALKOVA ◽  
D. H. SAVILLE ◽  
S. M. FITZPATRICK
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Embryo Development ◽  
Ultrastructural Study ◽  
Definitive Host ◽  
Parent Body ◽  
Common Eider ◽  
Somateria Mollissima ◽  
Transmission Electron ◽  
The Common

The parthenogenetic metacercarial stages of the gymnophallid trematode Cercaria margaritensis are found in the extrapallial cavity of the subtidal prosobranch mollusc Margarites helicinus. The primary metacercariae (M1) produce second-generation metacercariae (M2) which become independent and give rise to M3 metacercariae which are infective to the definitive host, the common eider (Somateria mollissima). This study used transmission electron microscopy to follow the development of M2 inside M1 organisms and M3 inside M2 organisms. The process is similar in both cases with embryos developing from individual cells from the parent body walls. In each case the brood sac was divided into brood chambers by multilaminated cells and both M2 and M3 embryos developed inside embryonic membranes that originated from specialized blastomeres. The tegument of M2 and M3 embryos developed in a similar manner underneath the embryonic membrane. Both the multilaminated cells and the embryonic membranes possessed features that indicated that they are involved in transport of nutrients. It is suggested that the continuous nature of M2 and M3 embryo development may well be similar to that postulated for ancestral digeneans.

Blood Supply and Function of the Tegmentum Vasculosum (Stria Vascularis) of the Duckling Cochlea

1999 ◽  
Vol 5 (S2) ◽  
pp. 1194-1195
Author(s):  
F.E. Hossler
Keyword(s):  
Electron Microscopy ◽  
Blood Supply ◽  
Carotid Arteries ◽  
Stria Vascularis ◽  
Light And Electron Microscopy ◽  
Corrosion Casting ◽  
The Common ◽  
And Function ◽  
Tegmentum Vasculosum ◽  
Common Carotid Arteries

On the basis of ultrastructural, biochemical, cytochemical, and electro-physiological evidence, the stria vascularis, a highly vascular epithelium of the mammalian cochlea, has been implicated as one site of endolymph synthesis. It would seem natural to suspect that its highly developed counterpart in the avian cochlea, the tegmentum vasculosum (TV), might have a similar function. This study utilizes routine light and electron microscopy, biochemistry, cytochemistry, and vascular corrosion casting to describe the structure and blood supply to the (TV) in the duckling and provide evidence for its involvement in endolymph synthesis.Four to 16 week-old ducklings (Anas platyrhyncos)were anesthetized and anticoagulated and perfused via the common carotid arteries with buffered, 2% glutaraldehyde for routine light microscopy or transmission or scanning electron microscopy, or with Mercox resin for vascular corrosion casting. Casts were macerated in 5% KOH and warm water to remove tissue, cleaned in formic acid and water, dried by lyophilization, mounted on stubs and viewed at 10-20 kv by SEM.

scholarly journals Dark Neurons of the Sensorimotor Cortex of White Rats after Acute Incomplete Ischemia in Terms of Artifacts Fixation and Neuroglial Relationships

2021 ◽  
Vol 10 (2) ◽  
pp. 9-22
Author(s):  
D. B. Avdeev ◽  
S. S. Stepanov ◽  
A. V. Gorbunova ◽  
A. Yu. Shoronova ◽  
L. M. Makar'eva ◽  
...  
Keyword(s):  
Sensorimotor Cortex ◽  
Carotid Arteries ◽  
Number Density ◽  
Dark Neurons ◽  
White Rats ◽  
The Common ◽  
Layer V ◽  
Common Carotid Arteries ◽  
The Brain ◽  
Incomplete Ischemia

The aimof research was to study morphofunctional signs of the sensorimotor "dark neurons" formation in the cerebrum of sexually mature white rats under normal conditions and in 40 minutesafter the common carotid arteries (CCA) occlusion.Material and methods.Acute ischemia was simulated in white Wistar rats by a 40-min CCA occlusion. The brain was fixed by immersion and perfusion methods. A comparative morphometric assessment of cyto-and gliocytoarchitectonics of the neocortex was carried out under normal conditions (n = 6), 1 (n = 6), 3 (n= 6), and in 7 days (n = 6) after the common carotid arteries (CCA) occlusion. The Nissl staining, hematoxylin and eosin staining, immunohistochemical typing NSE, MAP-2, HSP-70, p38, CASP3, GFAP and AIF1 were applied. The numerical density of normochromic and hyperchromic (dark) pyramidal neurons, oligodendrocytes, microgliocytes, and the relative area of edema –swelling zones were determined. Statistical hypotheses were tested by nonparametric methods using Statistica 8.0 software.Results.The method of the brain fixation significantly influenced the content of the artifact dark neurons,which are similar in morphology and tinctorial properties to degeneratively altered dark neurons. The appearance of reversibly and irreversibly degeneratively altered dark neurons in the sensorimotor cortex after the CCA occlusion was accompanied by an increase in the relative area of edema  –swelling zones (control  –5.4%, 1st day  –17.6%). The maximum content of degeneratively altered dark neurons (53%) was found in layer V in 7 days after ischemia. According to the findings of immunohistochemical typing NSE, MAP-2, HSP-70, p38, CASP3, the specific proteins of the most degeneratively altered dark neurons were retained, ensuring their restoration and the neural network functioning. The total number density of sensorimotor neurons decreased by 26.4% (p =0.001) in layer III, and by 18.5% in layer V (Mann –Whitney U Test; p = 0.01) in 7 days after the intervention. The revealed changes were of a diffuse focal character. In the zones of degeneratively altered dark neurons accumulation, the content of astrocytes, microgliocytes and oligodendrocytes increased. The neuro-astroglial index (control  –1.62) increased to 2.72 in 3 days after the CCA occlusion. The peak in the number density of microgliocyte s was noted in 1 day, and the oligodendrocytes in 7 days after acute incomplete ischemia (Mann –Whitney U Test; p0.001).Conclusion.After a 40-minute common carotid arteries occlusion, dark neurons were detected in layers III and V of the sensorimotor cortex with underlying hydropic dystrophy; their cytomorphological pro perties indicated the dynamics of their in vivo degenerative changes. Restoration of degeneratively altered dark neurons was accompanied  by  an  increase  in  the  number  of  satellite  oligodendrocytes,  astrocytes  and  microgliocytes. The  revealed changes were considered as one of the variants of reversible changes in neurons in response to moderate ischemic damage.

scholarly journals Protective effect of human umbilical cord mesenchymal stem cell-derived exosomes on rat retinal neurons in hyperglycemia through the brain-derived neurotrophic factor/TrkB pathway

2021 ◽  
Vol 14 (11) ◽  
pp. 1683-1689
Author(s):  
Xiang Gao ◽  
◽  
Xiao-Tian Zhang ◽  
Song Chen ◽  
◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Umbilical Cord ◽  
Neurotrophic Factor ◽  
Human Umbilical Cord ◽  
Retinal Neurons ◽  
Transmission Electron ◽  
The Brain

AIM: To explore whether human umbilical cord mesenchymal stem cell (hUCMSC)-derived exosomes (hUCMSC-Exos) protect rat retinal neurons in high-glucose (HG) conditions by activating the brain-derived neurotrophic factor (BDNF)-TrkB pathway. METHODS: hUCMSC-Exos were collected with differential ultracentrifugation methods and observed by transmission electron microscopy. Enzyme-linked immunosorbent assays (ELISAs) was used to quantify BDNF in hUCMSC-Exos, and Western blot was used to identify surface markers of hUCMSC-Exos. Rat retinal neurons were divided into 4 groups. Furthermore, cell viability, cell apoptosis, and TrkB protein expression were measured in retinal neurons. RESULTS: hUCMSCs and isolated hUCMSC-Exos were successfully cultured. All hUCMSC-Exos showed a diameter of 30 to 150 nm and had a phospholipid bimolecular membrane structure, as observed by transmission electron microscopy. ELISA showed the BDNF concentration of hUCMSCs-Exos was 2483.16±281.75. hUCMSCs-Exos effectively reduced the apoptosis of retinal neuron rate and improved neuron survival rate, meanwhile, the results of immunofluorescence verified the fluorescence intensity of TrKB in neurons increased. And all above effects were reduced by treated hUCMSCs-Exos with BDNF inhibitors. hUCMSC-Exos effectively reduced the apoptosis rate of retinal neurons by activating the BDNF-TrkB pathway in a HG environment. CONCLUSION: In the HG environment, hUCMSC-Exos could carry BDNF into rat retinal neurons, inhibiting neuronal apoptosis by activating the BDNF-TrkB pathway.

scholarly journals Rabies-Like Inclusions in Dogs

1989 ◽  
Vol 1 (4) ◽  
pp. 333-338 ◽  
Author(s):  
Jerome C. Nietfeld ◽  
Pauline M. Rakich ◽  
David E. Tyler ◽  
Rudy W. Bauer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rabies Virus ◽  
Inclusion Bodies ◽  
Fluorescent Antibody ◽  
Immunoperoxidase Staining ◽  
Immunoperoxidase Method ◽  
Transmission Electron ◽  
The Brain ◽  
Brain Tissues

Inclusion bodies, indistinguishable from rabies inclusion bodies (Negri bodies), were found in the brains of 8 nonrabid dogs. The inclusions were compared to Negri bodies present in neurons of rabies-positive animals and examined for the presence of rabies virus by a combination of immunoperoxidase staining (7 cases), fluorescent antibody (FA) staining (1 case), and transmission electron microscopy (4 cases). Positive immunoperoxidase staining for rabies was obtained in brain tissues from FA rabies-positive animals. All brain tissues from the 7 dogs stained by the immunoperoxidase method and the brain from the 1 dog stained by the FA method were negative for rabies. Rabies virus was not found in inclusion-containing neurons in the cases examined by transmission electron microscopy. These results emphasize the importance of FA testing and mouse inoculation for the diagnosis of rabies.

Some Recent Results on the 3C-SiC Structural Defects

2010 ◽  
Vol 159 ◽  
pp. 39-48 ◽  
Author(s):  
Maya Marinova ◽  
Alkyoni Mantzari ◽  
Efstathios K. Polychroniadis
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Layer Growth ◽  
Structural Defects ◽  
Vapour Transport ◽  
Transmission Electron ◽  
Continuous Feed ◽  
The Common

This work presents some recent results on the 3C-SiC structural defects, studied by Transmission Electron Microscopy (TEM). The samples studied were grown in several laboratories, using different methods. Commonly used methods for growth are Sublimation Epitaxy (SE), Physical Vapour Transport (PVT), Continuous Feed Physical Vapour Transport (CF-PVT), Chemical Vapour Deposition (CVD), and Liquid Phase Epitaxy (LPE). In all these methods, for both bulk and epitaxial layer growth, substrates from other polytypes are exploited like the common hexagonal polytypes 4H- and 6H-SiC or 3C-SiC seeds both in (111) and (100) orientation.

scholarly journals Correlative Light and Transmission Electron Microscopy Showed Details of Mitophagy by Mitochondria Quality Control in Propionic Acid Treated SH-SY5Y Cell

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4336
Author(s):  
Minkyo Jung ◽  
Hyosun Choi ◽  
Jaekwang Kim ◽  
Ji Young Mun
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Propionic Acid ◽  
Hippocampal Neurons ◽  
Acid Treatment ◽  
Light And Electron Microscopy ◽  
Quality Monitoring ◽  
Selective Autophagy ◽  
Transmission Electron ◽  
The Brain

Propionic acid is a metabolite of the microbiome and can be transported to the brain. Previous data show that propionic acid changes mitochondrial biogenesis in SH-SY5Y cells and induces abnormal autophagy in primary hippocampal neurons. Maintaining mitochondrial function is key to homeostasis in neuronal cells, and mitophagy is the selective autophagy involved in regulating mitochondrial quality. Monitoring mitophagy though light microscopy or conventional transmission electron microscopy separately is insufficient because phases of mitophagy, including autophagosome and autolysosome in nano-resolution, are critical for studies of function. Therefore, we used correlative light and electron microscopy to investigate mitochondrial quality in SH-SY5Y cells after propionic acid treatment to use the advantages of both techniques. We showed, with this approach, that propionic acid induces mitophagy associated with mitochondrial quality.

Electron Diffraction and TEM Studies of Y1Ba2Cu3O7−x

1987 ◽  
Vol 99 ◽  
Author(s):  
R. Pérez ◽  
J. G. Pérez-Ramírez ◽  
M. Avalos ◽  
J. Reyes ◽  
L. Martinez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Optical Microscopy ◽  
Image Contrast ◽  
Zone Axis ◽  
Twin Boundaries ◽  
Boundary Area ◽  
Transmission Electron ◽  
The Common

ABSTRACTOptical microscopy and transmission electron microscopy show that most of the crystalline grains in Y1Ba2Cu3O7−x superconducting specimens have large number of twins. These bands of different image contrast have similar microdiffraction patterns. However the diffraction conditions are different and correspond to different tilts of the crystalline grains along one of the zone axis. HREM images of these twin boundaries indicate that the boundary area has appreciable dimensions and both matrix and twin crystals show the existence of a superstructure with double of the common periodicity obtained under [001] diffraction conditions.

scholarly journals A flat embedding method for transmission electron microscopy reveals an unknown mechanism of tetracycline

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Michaela Wenzel ◽  
Marien P. Dekker ◽  
Biwen Wang ◽  
Maroeska J. Burggraaf ◽  
Wilbert Bitter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Large Scale ◽  
Embedding Method ◽  
Peripheral Membrane Proteins ◽  
Transmission Electron ◽  
Cell Sample ◽  
Flat Embedding ◽  
Induced Changes ◽  
Membrane Deformations

AbstractTransmission electron microscopy of cell sample sections is a popular technique in microbiology. Currently, ultrathin sectioning is done on resin-embedded cell pellets, which consumes milli- to deciliters of culture and results in sections of randomly orientated cells. This is problematic for rod-shaped bacteria and often precludes large-scale quantification of morphological phenotypes due to the lack of sufficient numbers of longitudinally cut cells. Here we report a flat embedding method that enables observation of thousands of longitudinally cut cells per single section and only requires microliter culture volumes. We successfully applied this technique to Bacillus subtilis, Escherichia coli, Mycobacterium bovis, and Acholeplasma laidlawii. To assess the potential of the technique to quantify morphological phenotypes, we monitored antibiotic-induced changes in B. subtilis cells. Surprisingly, we found that the ribosome inhibitor tetracycline causes membrane deformations. Further investigations showed that tetracycline disturbs membrane organization and localization of the peripheral membrane proteins MinD, MinC, and MreB. These observations are not the result of ribosome inhibition but constitute a secondary antibacterial activity of tetracycline that so far has defied discovery.

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