Search results for "Ultrastructure"
showing 10 items of 224 documents
Ultrastructural evidence for protection of the outer hair cells of the inner ear during intense noise exposure by application of the organic calcium …
1999
Outer hair cells could be protected during intense noise exposure by the application of the calcium channel blocker diltiazem given before and after noise treatment. After various experimental approaches, the ultrastructural morphology was analysed for the different animal populations in the basal part of the second turn of the cochlea, which was the most destroyed area after an acute noise trauma caused by a gun shot (sound pressure at the ear drum 156 dB, frequency maximum between 4 and 6 kHz). Compared to untreated control specimens (experimental animal group I), the outer hair cells in the basal part of the second turn of the cochlea were mostly destroyed without any diltiazem applicati…
Clinical, Microscopic and Ultrastructural Findings in a Case of Short Anagen Syndrome
2017
Short anagen syndrome is an uncommon and recently described disease characterized by many telogen hairs and short maximum hair length. We report here the case of a 3-year-old girl whose short, sparse, fine hair since birth was consistent with short anagen syndrome. X-ray microanalysis demonstrated normal composition of the main bioelements of her hairs.
The Harderian Gland of the Djungarian Hamster (<i>Phodopus sungorus</i>): Light- and Electron-Microscopical Investigations
1993
The Harderian gland of the Djungarian hamster Phodopus sungorus was investigated by light and electron microscopy in adult animals of both sexes, held under either long or short photoperiods. These glands have a tubuloalveolar structure. Epithelial cells were seen as small cylindric cells with a large, round nucleus located basally, many small vacuoles distributed throughout the cytoplasm (type I cells) or as rather broad cells with larger vacuoles (type II cells). The ratio of both cell types differed from 1:1 to 2:1 (type I:type II), regardless of the animal’s sex. In the electron microscope, abundant smooth endoplasmic reticulum of the vesicular type and rod-like or oval-shaped mitochond…
Clinical and ultrastructural observations of maturing human frontal cortex. Part I (Biopsy material of hydrocephalic infants).
1988
Three of 30 human cerebral cortex biopsies from infants treated for hydrocephalus by shunt operation are described. The descriptions include an account of their case history, the clinical methods, and the operational procedures. The biopsy specimens were studied in semithin and ultrathin sections. Attention is drawn to normal synapse formation but also to neuronal degenerative changes due to hydrocephalus.
Sex-specific reaction of liver ultrastructure in zebra fish (Brachydanio rerio) after prolonged sublethal exposure to 4-nitrophenol
1989
Abstract Morphological alterations of the liver of zebra fish ( Brachydanio rerio ) following prolonged exposure to 0.1, 1 and 5 mg · l −1 4-nitrophenol (4-NP) were investigated by means of light and electron microscopy. Based on marked sexual dimorphism in control animals, liver recactions were both sex- and dose-dependent. Whereas at 0.1 mg·1 −1 only minor changes could be revealed, there were numerous structural modifications at 1 mg·1 −1 : Whereas male fish primarily react with a proliferation of smooth endoplasmic reticulum, female fish display a high degree of fenetrastion within cisternate of the rough endoplasmic reticulum. Both sexes exhibit infiltration of macrophages and lymphocy…
Pineal 'synaptic' ribbons in sympathectomized rats.
1989
The melatonin metabolism in the mammalian pineal gland is under the clear influence of sympathetic fibers originating in the superior cervical ganglia (SCG). Previous studies suggested that also pineal ‘synaptic’ ribbons (SR) are regulated by the gland’s sympathetic innervation. To gain more insight into the mechanisms involved SR numbers were determined in adult rats which were chemically sympathectomized as newborns by injection of 6-hydroxydopamine (6-OHDA). In control animals (saline injections), a clear day/night difference in the number of SR is present. In sympathectomized animals SR are higher in number throughout the 24-hour cycle but are not significantly elevated at night. The pr…
Short- and long-term effects of vinblastine on the rat adrenal medulla
1979
The effects of a single high dose (10mg/kg) of vinblastine (vb) sulfate (“Velbe”, Lilly) on the ultrastructure, catecholamine (CA) content and activity of CA-synthesizing enzymes of the rat adrenal medulla were studied for up to 120h after intravenous injection of the drug.
Intravenous SPION-labeled adipocyte-derived stem cells targeted to the brain by magnetic attraction in a rat stroke model: An ultrastructural insight…
2021
Abstract Mesenchymal stem cell therapy after stroke is a promising option investigated in animal models and clinical trials. The intravenous route is commonly used in clinical settings guaranteeing an adequate safety profile although low yields of engraftment. In this report, rats subjected to ischemic stroke were injected with adipose-derived stem cells (ADSCs) labeled with superparamagnetic iron oxide nanoparticles (SPIONs) applying an external magnetic field in the skull to retain the cells. Although most published studies demonstrate viability of ADSCs, only a few have used ultrastructural techniques. In our study, the application of a local magnetic force resulted in a tendency for hig…
On the Ultrastructure and Function of Rhogocytes from the Pond Snail Lymnaea stagnalis
2015
Rhogocytes, also termed “pore cells”, occur as solitary or clustered cells in the connective tissue of gastropod molluscs. Rhogocytes possess an enveloping lamina of extracellular matrix and enigmatic extracellular lacunae bridged by cytoplasmic bars that form 20 nm diaphragmatic slits likely to act as a molecular sieve. Recent papers highlight the embryogenesis and ultrastructure of these cells, and their role in heavy metal detoxification. Rhogocytes are the site of hemocyanin or hemoglobin biosynthesis in gastropods. Based on electron microscopy, we recently proposed a possible pathway of hemoglobin exocytosis through the slit apparatus, and provided molecular evidence of a common phylog…
A genomic reappraisal of symbiotic function in the aphid/Buchnera symbiosis: reduced transporter sets and variable membrane organisations.
2011
International audience; Buchnera aphidicola is an obligate symbiotic bacterium that sustains the physiology of aphids by complementing their exclusive phloem sap diet. In this study, we reappraised the transport function of different Buchnera strains, from the aphids Acyrthosiphon pisum, Schizaphis graminum, Baizongia pistaciae and Cinara cedri, using the re-annotation of their transmembrane proteins coupled with an exploration of their metabolic networks. Although metabolic analyses revealed high interdependencies between the host and the bacteria, we demonstrate here that transport in Buchnera is assured by low transporter diversity, when compared to free-living bacteria, being mostly bas…